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Sample records for bacterial flagellar bundling

  1. Exchange of rotor components in functioning bacterial flagellar motor

    International Nuclear Information System (INIS)

    Fukuoka, Hajime; Inoue, Yuichi; Terasawa, Shun; Takahashi, Hiroto; Ishijima, Akihiko

    2010-01-01

    The bacterial flagellar motor is a rotary motor driven by the electrochemical potential of a coupling ion. The interaction between a rotor and stator units is thought to generate torque. The overall structure of flagellar motor has been thought to be static, however, it was recently proved that stators are exchanged in a rotating motor. Understanding the dynamics of rotor components in functioning motor is important for the clarifying of working mechanism of bacterial flagellar motor. In this study, we focused on the dynamics and the turnover of rotor components in a functioning flagellar motor. Expression systems for GFP-FliN, FliM-GFP, and GFP-FliG were constructed, and each GFP-fusion was functionally incorporated into the flagellar motor. To investigate whether the rotor components are exchanged in a rotating motor, we performed fluorescence recovery after photobleaching experiments using total internal reflection fluorescence microscopy. After photobleaching, in a tethered cell producing GFP-FliN or FliM-GFP, the recovery of fluorescence at the rotational center was observed. However, in a cell producing GFP-FliG, no recovery of fluorescence was observed. The transition phase of fluorescence intensity after full or partially photobleaching allowed the turnover of FliN subunits to be calculated as 0.0007 s -1 , meaning that FliN would be exchanged in tens of minutes. These novel findings indicate that a bacterial flagellar motor is not a static structure even in functioning state. This is the first report for the exchange of rotor components in a functioning bacterial flagellar motor.

  2. Mechanics of torque generation in the bacterial flagellar motor.

    Science.gov (United States)

    Mandadapu, Kranthi K; Nirody, Jasmine A; Berry, Richard M; Oster, George

    2015-08-11

    The bacterial flagellar motor (BFM) is responsible for driving bacterial locomotion and chemotaxis, fundamental processes in pathogenesis and biofilm formation. In the BFM, torque is generated at the interface between transmembrane proteins (stators) and a rotor. It is well established that the passage of ions down a transmembrane gradient through the stator complex provides the energy for torque generation. However, the physics involved in this energy conversion remain poorly understood. Here we propose a mechanically specific model for torque generation in the BFM. In particular, we identify roles for two fundamental forces involved in torque generation: electrostatic and steric. We propose that electrostatic forces serve to position the stator, whereas steric forces comprise the actual "power stroke." Specifically, we propose that ion-induced conformational changes about a proline "hinge" residue in a stator α-helix are directly responsible for generating the power stroke. Our model predictions fit well with recent experiments on a single-stator motor. The proposed model provides a mechanical explanation for several fundamental properties of the flagellar motor, including torque-speed and speed-ion motive force relationships, backstepping, variation in step sizes, and the effects of key mutations in the stator.

  3. Bacterial flagellar capping proteins adopt diverse oligomeric states

    Energy Technology Data Exchange (ETDEWEB)

    Postel, Sandra; Deredge, Daniel; Bonsor, Daniel A.; Yu, Xiong; Diederichs, Kay; Helmsing, Saskia; Vromen, Aviv; Friedler, Assaf; Hust, Michael; Egelman, Edward H.; Beckett, Dorothy; Wintrode, Patrick L.; Sundberg, Eric J. (UV); (Braunschweig); (Maryland-MED); (Konstanz); (Maryland); (Hebrew)

    2016-09-24

    Flagella are crucial for bacterial motility and pathogenesis. The flagellar capping protein (FliD) regulates filament assembly by chaperoning and sorting flagellin (FliC) proteins after they traverse the hollow filament and exit the growing flagellum tip. In the absence of FliD, flagella are not formed, resulting in impaired motility and infectivity. Here, we report the 2.2 Å resolution X-ray crystal structure of FliD fromPseudomonas aeruginosa, the first high-resolution structure of any FliD protein from any bacterium. Using this evidence in combination with a multitude of biophysical and functional analyses, we find thatPseudomonasFliD exhibits unexpected structural similarity to other flagellar proteins at the domain level, adopts a unique hexameric oligomeric state, and depends on flexible determinants for oligomerization. Considering that the flagellin filaments on which FliD oligomers are affixed vary in protofilament number between bacteria, our results suggest that FliD oligomer stoichiometries vary across bacteria to complement their filament assemblies.

  4. Protein export through the bacterial flagellar type III export pathway.

    Science.gov (United States)

    Minamino, Tohru

    2014-08-01

    For construction of the bacterial flagellum, which is responsible for bacterial motility, the flagellar type III export apparatus utilizes both ATP and proton motive force across the cytoplasmic membrane and exports flagellar proteins from the cytoplasm to the distal end of the nascent structure. The export apparatus consists of a membrane-embedded export gate made of FlhA, FlhB, FliO, FliP, FliQ, and FliR and a water-soluble ATPase ring complex consisting of FliH, FliI, and FliJ. FlgN, FliS, and FliT act as substrate-specific chaperones that do not only protect their cognate substrates from degradation and aggregation in the cytoplasm but also efficiently transfer the substrates to the export apparatus. The ATPase ring complex facilitates the initial entry of the substrates into the narrow pore of the export gate. The export gate by itself is a proton-protein antiporter that uses the two components of proton motive force, the electric potential difference and the proton concentration difference, for different steps of the export process. A specific interaction of FlhA with FliJ located in the center of the ATPase ring complex allows the export gate to efficiently use proton motive force to drive protein export. The ATPase ring complex couples ATP binding and hydrolysis to its assembly-disassembly cycle for rapid and efficient protein export cycle. This article is part of a Special Issue entitled: Protein trafficking and secretion in bacteria. Guest Editors: Anastassios Economou and Ross Dalbey. © 2013 Elsevier B.V. All rights reserved.

  5. Impact of fluorescent protein fusions on the bacterial flagellar motor.

    Science.gov (United States)

    Heo, M; Nord, A L; Chamousset, D; van Rijn, E; Beaumont, H J E; Pedaci, F

    2017-10-03

    Fluorescent fusion proteins open a direct and unique window onto protein function. However, they also introduce the risk of perturbation of the function of the native protein. Successful applications of fluorescent fusions therefore rely on a careful assessment and minimization of the side effects, but such insight is still lacking for many applications. This is particularly relevant in the study of the internal dynamics of motor proteins, where both the chemical and mechanical reaction coordinates can be affected. Fluorescent proteins fused to the stator of the Bacterial Flagellar Motor (BFM) have previously been used to unveil the motor subunit dynamics. Here we report the effects on single motors of three fluorescent proteins fused to the stators, all of which altered BFM behavior. The torque generated by individual stators was reduced while their stoichiometry remained unaffected. MotB fusions decreased the switching frequency and induced a novel bias-dependent asymmetry in the speed in the two directions. These effects could be mitigated by inserting a linker at the fusion point. These findings provide a quantitative account of the effects of fluorescent fusions to the stator on BFM dynamics and their alleviation- new insights that advance the use of fluorescent fusions to probe the dynamics of protein complexes.

  6. Model Studies of the Dynamics of Bacterial Flagellar Motors

    Energy Technology Data Exchange (ETDEWEB)

    Bai, F; Lo, C; Berry, R; Xing, J

    2009-03-19

    The Bacterial Flagellar Motor is a rotary molecular machine that rotates the helical filaments which propel swimming bacteria. Extensive experimental and theoretical studies exist on the structure, assembly, energy input, power generation and switching mechanism of the motor. In our previous paper, we explained the general physics underneath the observed torque-speed curves with a simple two-state Fokker-Planck model. Here we further analyze this model. In this paper we show (1) the model predicts that the two components of the ion motive force can affect the motor dynamics differently, in agreement with the latest experiment by Lo et al.; (2) with explicit consideration of the stator spring, the model also explains the lack of dependence of the zero-load speed on stator number in the proton motor, recently observed by Yuan and Berg; (3) the model reproduces the stepping behavior of the motor even with the existence of the stator springs and predicts the dwelling time distribution. Predicted stepping behavior of motors with two stators is discussed, and we suggest future experimental verification.

  7. Model Studies of the Dynamics of Bacterial Flagellar Motors

    Science.gov (United States)

    Bai, Fan; Lo, Chien-Jung; Berry, Richard M.; Xing, Jianhua

    2009-01-01

    Abstract The bacterial flagellar motor is a rotary molecular machine that rotates the helical filaments that propel swimming bacteria. Extensive experimental and theoretical studies exist on the structure, assembly, energy input, power generation, and switching mechanism of the motor. In a previous article, we explained the general physics underneath the observed torque-speed curves with a simple two-state Fokker-Planck model. Here, we further analyze that model, showing that 1), the model predicts that the two components of the ion motive force can affect the motor dynamics differently, in agreement with latest experiments; 2), with explicit consideration of the stator spring, the model also explains the lack of dependence of the zero-load speed on stator number in the proton motor, as recently observed; and 3), the model reproduces the stepping behavior of the motor even with the existence of the stator springs and predicts the dwell-time distribution. The predicted stepping behavior of motors with two stators is discussed, and we suggest future experimental procedures for verification. PMID:19383460

  8. An intrinsically disordered linker controlling the formation and the stability of the bacterial flagellar hook

    OpenAIRE

    Barker, Clive S.; Meshcheryakova, Irina V.; Kostyukova, Alla S.; Freddolino, Peter L.; Samatey, Fadel A.

    2017-01-01

    Background In a macro-molecular complex, any minor change may prove detrimental. For a supra-molecular nano-machine like the bacterial flagellum, which consists of several distinct parts with specific characteristics, stability is important. During the rotation of the bacterial flagellar motor, which is located in the membrane, the flagella rotate at speeds between 200 and 2000 rpm, depending on the bacterial species. The hook substructure of the bacterial flagellum acts as a universal joint ...

  9. Hierarchical protein export mechanism of the bacterial flagellar type III protein export apparatus.

    Science.gov (United States)

    Minamino, Tohru

    2018-06-01

    The bacterial flagellum is supramolecular motility machinery consisting of the basal body, the hook and the filament. Flagellar proteins are translocated across the cytoplasmic membrane via a type III protein export apparatus, diffuse down the central channel of the growing structure and assemble at the distal end. Flagellar assembly begins with the basal body, followed by the hook and finally the filament. The completion of hook assembly is the most important morphological checkpoint of the sequential flagellar assembly process. When the hook reaches its mature length of about 55 nm in Salmonella enterica, the type III protein export apparatus switches export specificity from proteins required for the structure and assembly of the hook to those responsible for filament assembly, thereby terminating hook assembly and initiating filament assembly. Three flagellar proteins, namely FliK, FlhB and FlhA, are responsible for this substrate specificity switching. Upon completion of the switching event, interactions among FlhA, the cytoplasmic ATPase complex and flagellar type III export chaperones establish the assembly order of the filament at the hook tip. Here, we describe our current understanding of a hierarchical protein export mechanism used in flagellar type III protein export.

  10. Changes in the flagellar bundling time account for variations in swimming behavior of flagellated bacteria in viscous media

    Science.gov (United States)

    Qu, Zijie; Temel, Fatma; Henderikx, Rene; Breuer, Kenneth

    2017-11-01

    The motility of bacteria E.coli in viscous fluids has been widely studied, although conflicting results on the effect of viscosity on swimming speed abound. The swimming mode of wild-type E.coli is idealized as a run-and-tumble sequence in which periods of straight swimming at a constant speed are randomly interrupted by a tumble, defined as a sudden change of direction with a very low speed. Using a tracking microscope, we follow cells for extended time and find that the swimming behavior of a single cell can exhibit a variety of behaviors including run-and-tumble and ``slow-random-walk'' in which the cells move at relatively low speed without the characteristic run. Although the characteristic swimming speed varies between individuals and in different polymer solutions, we find that the skewness of the speed distribution is solely a function of viscosity, and uniquely determines the ratio of the average speed to the characteristic run speed. Using Resistive Force Theory and the cell-specific measured characteristic run speed, we show that differences in the swimming behavior observed in solutions of different viscosity are due to changes in the flagellar bundling time, which increases as the viscosity rises, due to lower rotation rate of the flagellar motor. National Science Foundation.

  11. Autonomously responsive pumping by a bacterial flagellar forest: A mean-field approach

    Science.gov (United States)

    Martindale, James D.; Fu, Henry C.

    2017-09-01

    This study is motivated by a microfluidic device that imparts a magnetic torque on an array of bacterial flagella. Bacterial flagella can transform their helical geometry autonomously in response to properties of the background fluid, which provides an intriguing mechanism allowing their use as an engineered element for the regulation or transport of chemicals in microscale applications. The synchronization of flagellar phase has been widely studied in biological contexts, but here we examine the synchronization of flagellar tilt, which is necessary for effective pumping. We first examine the effects of helical geometry and tilt on the pumping flows generated by a single rotating flagellum. Next, we explore a mean-field model for an array of helical flagella to understand how collective tilt arises and influences pumping. The mean-field methodology allows us to take into account possible phase differences through a time-averaging procedure and to model an infinite array of flagella. We find array separation distances, magnetic field strengths, and rotation frequencies that produce nontrivial self-consistent pumping solutions. For individual flagella, pumping is reversed when helicity or rotation is reversed; in contrast, when collective effects are included, self-consistent tilted pumping solutions become untilted nonpumping solutions when helicity or rotation is reversed.

  12. The Bacterial Flagellar Type III Export Gate Complex Is a Dual Fuel Engine That Can Use Both H+ and Na+ for Flagellar Protein Export.

    Directory of Open Access Journals (Sweden)

    Tohru Minamino

    2016-03-01

    Full Text Available The bacterial flagellar type III export apparatus utilizes ATP and proton motive force (PMF to transport flagellar proteins to the distal end of the growing flagellar structure for self-assembly. The transmembrane export gate complex is a H+-protein antiporter, of which activity is greatly augmented by an associated cytoplasmic ATPase complex. Here, we report that the export gate complex can use sodium motive force (SMF in addition to PMF across the cytoplasmic membrane to drive protein export. Protein export was considerably reduced in the absence of the ATPase complex and a pH gradient across the membrane, but Na+ increased it dramatically. Phenamil, a blocker of Na+ translocation, inhibited protein export. Overexpression of FlhA increased the intracellular Na+ concentration in the presence of 100 mM NaCl but not in its absence, suggesting that FlhA acts as a Na+ channel. In wild-type cells, however, neither Na+ nor phenamil affected protein export, indicating that the Na+ channel activity of FlhA is suppressed by the ATPase complex. We propose that the export gate by itself is a dual fuel engine that uses both PMF and SMF for protein export and that the ATPase complex switches this dual fuel engine into a PMF-driven export machinery to become much more robust against environmental changes in external pH and Na+ concentration.

  13. The Bacterial Flagellar Type III Export Gate Complex Is a Dual Fuel Engine That Can Use Both H+ and Na+ for Flagellar Protein Export.

    Science.gov (United States)

    Minamino, Tohru; Morimoto, Yusuke V; Hara, Noritaka; Aldridge, Phillip D; Namba, Keiichi

    2016-03-01

    The bacterial flagellar type III export apparatus utilizes ATP and proton motive force (PMF) to transport flagellar proteins to the distal end of the growing flagellar structure for self-assembly. The transmembrane export gate complex is a H+-protein antiporter, of which activity is greatly augmented by an associated cytoplasmic ATPase complex. Here, we report that the export gate complex can use sodium motive force (SMF) in addition to PMF across the cytoplasmic membrane to drive protein export. Protein export was considerably reduced in the absence of the ATPase complex and a pH gradient across the membrane, but Na+ increased it dramatically. Phenamil, a blocker of Na+ translocation, inhibited protein export. Overexpression of FlhA increased the intracellular Na+ concentration in the presence of 100 mM NaCl but not in its absence, suggesting that FlhA acts as a Na+ channel. In wild-type cells, however, neither Na+ nor phenamil affected protein export, indicating that the Na+ channel activity of FlhA is suppressed by the ATPase complex. We propose that the export gate by itself is a dual fuel engine that uses both PMF and SMF for protein export and that the ATPase complex switches this dual fuel engine into a PMF-driven export machinery to become much more robust against environmental changes in external pH and Na+ concentration.

  14. Assembly and stoichiometry of the core structure of the bacterial flagellar type III export gate complex.

    Science.gov (United States)

    Fukumura, Takuma; Makino, Fumiaki; Dietsche, Tobias; Kinoshita, Miki; Kato, Takayuki; Wagner, Samuel; Namba, Keiichi; Imada, Katsumi; Minamino, Tohru

    2017-08-01

    The bacterial flagellar type III export apparatus, which is required for flagellar assembly beyond the cell membranes, consists of a transmembrane export gate complex and a cytoplasmic ATPase complex. FlhA, FlhB, FliP, FliQ, and FliR form the gate complex inside the basal body MS ring, although FliO is required for efficient export gate formation in Salmonella enterica. However, it remains unknown how they form the gate complex. Here we report that FliP forms a homohexameric ring with a diameter of 10 nm. Alanine substitutions of conserved Phe-137, Phe-150, and Glu-178 residues in the periplasmic domain of FliP (FliPP) inhibited FliP6 ring formation, suppressing flagellar protein export. FliO formed a 5-nm ring structure with 3 clamp-like structures that bind to the FliP6 ring. The crystal structure of FliPP derived from Thermotoga maritia, and structure-based photo-crosslinking experiments revealed that Phe-150 and Ser-156 of FliPP are involved in the FliP-FliP interactions and that Phe-150, Arg-152, Ser-156, and Pro-158 are responsible for the FliP-FliO interactions. Overexpression of FliP restored motility of a ∆fliO mutant to the wild-type level, suggesting that the FliP6 ring is a functional unit in the export gate complex and that FliO is not part of the final gate structure. Copurification assays revealed that FlhA, FlhB, FliQ, and FliR are associated with the FliO/FliP complex. We propose that the assembly of the export gate complex begins with FliP6 ring formation with the help of the FliO scaffold, followed by FliQ, FliR, and FlhB and finally FlhA during MS ring formation.

  15. Speed of the bacterial flagellar motor near zero load depends on the number of stator units.

    Science.gov (United States)

    Nord, Ashley L; Sowa, Yoshiyuki; Steel, Bradley C; Lo, Chien-Jung; Berry, Richard M

    2017-10-31

    The bacterial flagellar motor (BFM) rotates hundreds of times per second to propel bacteria driven by an electrochemical ion gradient. The motor consists of a rotor 50 nm in diameter surrounded by up to 11 ion-conducting stator units, which exchange between motors and a membrane-bound pool. Measurements of the torque-speed relationship guide the development of models of the motor mechanism. In contrast to previous reports that speed near zero torque is independent of the number of stator units, we observe multiple speeds that we attribute to different numbers of units near zero torque in both Na + - and H + -driven motors. We measure the full torque-speed relationship of one and two H + units in Escherichia coli by selecting the number of H + units and controlling the number of Na + units in hybrid motors. These experiments confirm that speed near zero torque in H + -driven motors increases with the stator number. We also measured 75 torque-speed curves for Na + -driven chimeric motors at different ion-motive force and stator number. Torque and speed were proportional to ion-motive force and number of stator units at all loads, allowing all 77 measured torque-speed curves to be collapsed onto a single curve by simple rescaling. Published under the PNAS license.

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

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    Alessandro Pandini

    Full Text Available 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

  17. Temperature Dependences of Torque Generation and Membrane Voltage in the Bacterial Flagellar Motor

    Science.gov (United States)

    Inoue, Yuichi; Baker, Matthew A.B.; Fukuoka, Hajime; Takahashi, Hiroto; Berry, Richard M.; Ishijima, Akihiko

    2013-01-01

    In their natural habitats bacteria are frequently exposed to sudden changes in temperature that have been shown to affect their swimming. With our believed to be new methods of rapid temperature control for single-molecule microscopy, we measured here the thermal response of the Na+-driven chimeric motor expressed in Escherichia coli cells. Motor torque at low load (0.35 μm bead) increased linearly with temperature, twofold between 15°C and 40°C, and torque at high load (1.0 μm bead) was independent of temperature, as reported for the H+-driven motor. Single cell membrane voltages were measured by fluorescence imaging and these were almost constant (∼120 mV) over the same temperature range. When the motor was heated above 40°C for 1–2 min the torque at high load dropped reversibly, recovering upon cooling below 40°C. This response was repeatable over as many as 10 heating cycles. Both increases and decreases in torque showed stepwise torque changes with unitary size ∼150 pN nm, close to the torque of a single stator at room temperature (∼180 pN nm), indicating that dynamic stator dissociation occurs at high temperature, with rebinding upon cooling. Our results suggest that the temperature-dependent assembly of stators is a general feature of flagellar motors. PMID:24359752

  18. Molecular mechanism of bundle formation by the bacterial actin ParM

    Energy Technology Data Exchange (ETDEWEB)

    Popp, David, E-mail: dpopp@imcb.a-star.edu.sg [ERATO ' Actin Filament Dynamics' Project, Japan Science and Technology Corporation, c/o RIKEN Harima Institute at Spring 8, 1-1-1 Kouto, Sayo, Hyogo 679-5148 (Japan); Institute of Molecular and Cell Biology, 61 Biopolis Drive, Proteos, 138673 Singapore (Singapore); Narita, Akihiro [ERATO ' Actin Filament Dynamics' Project, Japan Science and Technology Corporation, c/o RIKEN Harima Institute at Spring 8, 1-1-1 Kouto, Sayo, Hyogo 679-5148 (Japan); Nagoya University Graduate School of Science, Structural Biology Research Center and Division of Biological Sciences, Furo-cho, Chikusa-ku, Nagoya 464-8601 (Japan); Iwasa, Mitsusada [ERATO ' Actin Filament Dynamics' Project, Japan Science and Technology Corporation, c/o RIKEN Harima Institute at Spring 8, 1-1-1 Kouto, Sayo, Hyogo 679-5148 (Japan); Maeda, Yuichiro [ERATO ' Actin Filament Dynamics' Project, Japan Science and Technology Corporation, c/o RIKEN Harima Institute at Spring 8, 1-1-1 Kouto, Sayo, Hyogo 679-5148 (Japan); Nagoya University Graduate School of Science, Structural Biology Research Center and Division of Biological Sciences, Furo-cho, Chikusa-ku, Nagoya 464-8601 (Japan); Robinson, Robert C. [Institute of Molecular and Cell Biology, 61 Biopolis Drive, Proteos, 138673 Singapore (Singapore)

    2010-01-22

    The actin homolog ParM plays a microtubule-like role in segregating DNA prior to bacterial cell division. Fluorescence and cryo-electron microscopy have shown that ParM forms filament bundles between separating DNA plasmids in vivo. Given the lack of ParM bundling proteins it remains unknown how ParM bundles form at the molecular level. Here we show using time-lapse TIRF microscopy, under in vitro molecular crowding conditions, that ParM-bundle formation consists of two distinct phases. At the onset of polymerization bundle thickness and shape are determined in the form of nuclei of short helically disordered filaments arranged in a liquid-like lattice. These nuclei then undergo an elongation phase whereby they rapidly increase in length. At steady state, ParM bundles fuse into one single large aggregate. This behavior had been predicted by theory but has not been observed for any other cytomotive biopolymer, including F-actin. We employed electron micrographs of ParM rafts, which are 2-D analogs of 3-D bundles, to identify the main molecular interfilament contacts within these suprastructures. The interface between filaments is similar for both parallel and anti-parallel orientations and the distribution of filament polarity is random within a bundle. We suggest that the interfilament interactions are not due to the interactions of specific residues but rather to long-range, counter ion mediated, electrostatic attractive forces. A randomly oriented bundle ensures that the assembly is rigid and that DNA may be captured with equal efficiency at both ends of the bundle via the ParR binding protein.

  19. Hybrid Bacterial Foraging and Particle Swarm Optimization for detecting Bundle Branch Block.

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    Kora, Padmavathi; Kalva, Sri Ramakrishna

    2015-01-01

    Abnormal cardiac beat identification is a key process in the detection of heart diseases. Our present study describes a procedure for the detection of left and right bundle branch block (LBBB and RBBB) Electrocardiogram (ECG) patterns. The electrical impulses that control the cardiac beat face difficulty in moving inside the heart. This problem is termed as bundle branch block (BBB). BBB makes it harder for the heart to pump blood effectively through the heart circulatory system. ECG feature extraction is a key process in detecting heart ailments. Our present study comes up with a hybrid method combining two heuristic optimization methods: Bacterial Forging Optimization (BFO) and Particle Swarm Optimization (PSO) for the feature selection of ECG signals. One of the major controlling forces of BFO algorithm is the chemotactic movement of a bacterium that models a test solution. The chemotaxis process of the BFO depends on random search directions which may lead to a delay in achieving the global optimum solution. The hybrid technique: Bacterial Forging-Particle Swarm Optimization (BFPSO) incorporates the concepts from BFO and PSO and it creates individuals in a new generation. This BFPSO method performs local search through the chemotactic movement of BFO and the global search over the entire search domain is accomplished by a PSO operator. The BFPSO feature values are given as the input for the Levenberg-Marquardt Neural Network classifier.

  20. The non-flagellar type III secretion system evolved from the bacterial flagellum and diversified into host-cell adapted systems.

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    Sophie S Abby

    2012-09-01

    Full Text Available Type 3 secretion systems (T3SSs are essential components of two complex bacterial machineries: the flagellum, which drives cell motility, and the non-flagellar T3SS (NF-T3SS, which delivers effectors into eukaryotic cells. Yet the origin, specialization, and diversification of these machineries remained unclear. We developed computational tools to identify homologous components of the two systems and to discriminate between them. Our analysis of >1,000 genomes identified 921 T3SSs, including 222 NF-T3SSs. Phylogenomic and comparative analyses of these systems argue that the NF-T3SS arose from an exaptation of the flagellum, i.e. the recruitment of part of the flagellum structure for the evolution of the new protein delivery function. This reconstructed chronology of the exaptation process proceeded in at least two steps. An intermediate ancestral form of NF-T3SS, whose descendants still exist in Myxococcales, lacked elements that are essential for motility and included a subset of NF-T3SS features. We argue that this ancestral version was involved in protein translocation. A second major step in the evolution of NF-T3SSs occurred via recruitment of secretins to the NF-T3SS, an event that occurred at least three times from different systems. In rhizobiales, a partial homologous gene replacement of the secretin resulted in two genes of complementary function. Acquisition of a secretin was followed by the rapid adaptation of the resulting NF-T3SSs to multiple, distinct eukaryotic cell envelopes where they became key in parasitic and mutualistic associations between prokaryotes and eukaryotes. Our work elucidates major steps of the evolutionary scenario leading to extant NF-T3SSs. It demonstrates how molecular evolution can convert one complex molecular machine into a second, equally complex machine by successive deletions, innovations, and recruitment from other molecular systems.

  1. Detection of Bundle Branch Block using Adaptive Bacterial Foraging Optimization and Neural Network

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    Padmavthi Kora

    2017-03-01

    Full Text Available The medical practitioners analyze the electrical activity of the human heart so as to predict various ailments by studying the data collected from the Electrocardiogram (ECG. A Bundle Branch Block (BBB is a type of heart disease which occurs when there is an obstruction along the pathway of an electrical impulse. This abnormality makes the heart beat irregular as there is an obstruction in the branches of heart, this results in pulses to travel slower than the usual. Our current study involved is to diagnose this heart problem using Adaptive Bacterial Foraging Optimization (ABFO Algorithm. The Data collected from MIT/BIH arrhythmia BBB database applied to an ABFO Algorithm for obtaining best(important feature from each ECG beat. These features later fed to Levenberg Marquardt Neural Network (LMNN based classifier. The results show the proposed classification using ABFO is better than some recent algorithms reported in the literature.

  2. Microscopic Analysis of Bacterial Motility at High Pressure

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    Nishiyama, Masayoshi; Sowa, Yoshiyuki

    2012-01-01

    The bacterial flagellar motor is a molecular machine that converts an ion flux to the rotation of a helical flagellar filament. Counterclockwise rotation of the filaments allows them to join in a bundle and propel the cell forward. Loss of motility can be caused by environmental factors such as temperature, pH, and solvation. Hydrostatic pressure is also a physical inhibitor of bacterial motility, but the detailed mechanism of this inhibition is still unknown. Here, we developed a high-pressure microscope that enables us to acquire high-resolution microscopic images, regardless of applied pressures. We also characterized the pressure dependence of the motility of swimming Escherichia coli cells and the rotation of single flagellar motors. The fraction and speed of swimming cells decreased with increased pressure. At 80 MPa, all cells stopped swimming and simply diffused in solution. After the release of pressure, most cells immediately recovered their initial motility. Direct observation of the motility of single flagellar motors revealed that at 80 MPa, the motors generate torque that should be sufficient to join rotating filaments in a bundle. The discrepancy in the behavior of free swimming cells and individual motors could be due to the applied pressure inhibiting the formation of rotating filament bundles that can propel the cell body in an aqueous environment. PMID:22768943

  3. Nanobody-Displaying Flagellar Nanotubes.

    Science.gov (United States)

    Klein, Ágnes; Kovács, Mátyás; Muskotál, Adél; Jankovics, Hajnalka; Tóth, Balázs; Pósfai, Mihály; Vonderviszt, Ferenc

    2018-02-26

    In this work we addressed the problem how to fabricate self-assembling tubular nanostructures displaying target recognition functionalities. Bacterial flagellar filaments, composed of thousands of flagellin subunits, were used as scaffolds to display single-domain antibodies (nanobodies) on their surface. As a representative example, an anti-GFP nanobody was successfully inserted into the middle part of flagellin replacing the hypervariable surface-exposed D3 domain. A novel procedure was developed to select appropriate linkers required for functional internal insertion. Linkers of various lengths and conformational properties were chosen from a linker database and they were randomly attached to both ends of an anti-GFP nanobody to facilitate insertion. Functional fusion constructs capable of forming filaments on the surface of flagellin-deficient host cells were selected by magnetic microparticles covered by target GFP molecules and appropriate linkers were identified. TEM studies revealed that short filaments of 2-900 nm were formed on the cell surface. ITC and fluorescent measurements demonstrated that the fusion protein exhibited high binding affinity towards GFP. Our approach allows the development of functionalized flagellar nanotubes against a variety of important target molecules offering potential applications in biosensorics and bio-nanotechnology.

  4. Reactions of chicken sera to recombinant Campylobacter jejuni flagellar proteins.

    Science.gov (United States)

    Yeh, Hung-Yueh; Hiett, Kelli L; Line, John E

    2015-03-01

    Campylobacter jejuni is a Gram-negative spiral rod bacterium and is the leading but underreported bacterial food-borne pathogen that causes human campylobacteriosis worldwide. Raw or undercooked poultry products are regarded as a major source for human infection. C. jejuni flagella have been implicated in colonization and adhesion to the mucosal surface of chicken gastrointestinal tracts. Therefore, flagellar proteins would be the excellent targets for further investigation. In this report, we used the recombinant technology to generate a battery of C. jejuni flagellar proteins, which were purified by His tag affinity chromatography and determined antigenic profiles of these recombinant flagellar proteins using sera from chickens older than 6 weeks of age. The immunoblot results demonstrate that each chicken serum reacted to various numbers of recombinant flagellar proteins. Among these recombinant proteins, chicken sera reacted predominantly to the FlgE1, FlgK, FlhF, FliG and FliY proteins. These antibody screening results provide a rationale for further evaluation of these recombinant flagellar proteins as potential vaccines for chickens to improve food safety as well as investigation of host immune response to C. jejuni.

  5. H(+) and Na(+) are involved in flagellar rotation of the spirochete Leptospira.

    Science.gov (United States)

    Islam, Md Shafiqul; Morimoto, Yusuke V; Kudo, Seishi; Nakamura, Shuichi

    2015-10-16

    Leptospira is a spirochete possessing intracellular flagella. Each Leptospira flagellar filament is linked with a flagellar motor composed of a rotor and a dozen stators. For many bacterial species, it is known that the stator functions as an ion channel and that the ion flux through the stator is coupled with flagellar rotation. The coupling ion varies depending on the species; for example, H(+) is used in Escherichia coli, and Na(+) is used in Vibrio spp. to drive a polar flagellum. Although genetic and structural studies illustrated that the Leptospira flagellar motor also contains a stator, the coupling ion for flagellar rotation remains unknown. In the present study, we analyzed the motility of Leptospira under various pH values and salt concentrations. Leptospira cells displayed motility in acidic to alkaline pH. In the presence of a protonophore, the cells completely lost motility in acidic to neutral pH but displayed extremely slow movement under alkaline conditions. This result suggests that H(+) is a major coupling ion for flagellar rotation over a wide pH range; however, we also observed that the motility of Leptospira was significantly enhanced by the addition of Na(+), though it vigorously moved even under Na(+)-free conditions. These results suggest that H(+) is preferentially used and that Na(+) is secondarily involved in flagellar rotation in Leptospira. The flexible ion selectivity in the flagellar system could be advantageous for Leptospira to survive in a wide range of environment. Copyright © 2015 Elsevier Inc. All rights reserved.

  6. H+ and Na+ are involved in flagellar rotation of the spirochete Leptospira

    International Nuclear Information System (INIS)

    Islam, Md. Shafiqul; Morimoto, Yusuke V.; Kudo, Seishi; Nakamura, Shuichi

    2015-01-01

    Leptospira is a spirochete possessing intracellular flagella. Each Leptospira flagellar filament is linked with a flagellar motor composed of a rotor and a dozen stators. For many bacterial species, it is known that the stator functions as an ion channel and that the ion flux through the stator is coupled with flagellar rotation. The coupling ion varies depending on the species; for example, H + is used in Escherichia coli, and Na + is used in Vibrio spp. to drive a polar flagellum. Although genetic and structural studies illustrated that the Leptospira flagellar motor also contains a stator, the coupling ion for flagellar rotation remains unknown. In the present study, we analyzed the motility of Leptospira under various pH values and salt concentrations. Leptospira cells displayed motility in acidic to alkaline pH. In the presence of a protonophore, the cells completely lost motility in acidic to neutral pH but displayed extremely slow movement under alkaline conditions. This result suggests that H + is a major coupling ion for flagellar rotation over a wide pH range; however, we also observed that the motility of Leptospira was significantly enhanced by the addition of Na + , though it vigorously moved even under Na + -free conditions. These results suggest that H + is preferentially used and that Na + is secondarily involved in flagellar rotation in Leptospira. The flexible ion selectivity in the flagellar system could be advantageous for Leptospira to survive in a wide range of environment. - Highlights: • This is a study on input energy for motility in the spirochete Leptospira. • Leptospira biflexa exhibited active motility in acidic to alkaline pH. • Both H + and Na + are involved in flagellar rotation in Leptospira. • H + is a primary energy source, but Na + can secondarily enhance motility.

  7. H{sup +} and Na{sup +} are involved in flagellar rotation of the spirochete Leptospira

    Energy Technology Data Exchange (ETDEWEB)

    Islam, Md. Shafiqul [Department of Applied Physics, Graduate School of Engineering, Tohoku University, 6-6-05 Aoba, Aoba-ku, Sendai, Miyagi 980-8579 (Japan); Morimoto, Yusuke V. [Quantitative Biology Center, RIKEN, 6-2-3 Furuedai, Suita, Osaka 565-0874 (Japan); Graduate School of Frontier BioSciences, Osaka University, 1-3 Yamadaoka, Suita, Osaka 565-0871 (Japan); Kudo, Seishi [Department of Applied Physics, Graduate School of Engineering, Tohoku University, 6-6-05 Aoba, Aoba-ku, Sendai, Miyagi 980-8579 (Japan); Nakamura, Shuichi, E-mail: naka@bp.apph.tohoku.ac.jp [Department of Applied Physics, Graduate School of Engineering, Tohoku University, 6-6-05 Aoba, Aoba-ku, Sendai, Miyagi 980-8579 (Japan); Graduate School of Frontier BioSciences, Osaka University, 1-3 Yamadaoka, Suita, Osaka 565-0871 (Japan)

    2015-10-16

    Leptospira is a spirochete possessing intracellular flagella. Each Leptospira flagellar filament is linked with a flagellar motor composed of a rotor and a dozen stators. For many bacterial species, it is known that the stator functions as an ion channel and that the ion flux through the stator is coupled with flagellar rotation. The coupling ion varies depending on the species; for example, H{sup +} is used in Escherichia coli, and Na{sup +} is used in Vibrio spp. to drive a polar flagellum. Although genetic and structural studies illustrated that the Leptospira flagellar motor also contains a stator, the coupling ion for flagellar rotation remains unknown. In the present study, we analyzed the motility of Leptospira under various pH values and salt concentrations. Leptospira cells displayed motility in acidic to alkaline pH. In the presence of a protonophore, the cells completely lost motility in acidic to neutral pH but displayed extremely slow movement under alkaline conditions. This result suggests that H{sup +} is a major coupling ion for flagellar rotation over a wide pH range; however, we also observed that the motility of Leptospira was significantly enhanced by the addition of Na{sup +}, though it vigorously moved even under Na{sup +}-free conditions. These results suggest that H{sup +} is preferentially used and that Na{sup +} is secondarily involved in flagellar rotation in Leptospira. The flexible ion selectivity in the flagellar system could be advantageous for Leptospira to survive in a wide range of environment. - Highlights: • This is a study on input energy for motility in the spirochete Leptospira. • Leptospira biflexa exhibited active motility in acidic to alkaline pH. • Both H{sup +} and Na{sup +} are involved in flagellar rotation in Leptospira. • H{sup +} is a primary energy source, but Na{sup +} can secondarily enhance motility.

  8. Applying torque to the Escherichia coli flagellar motor using magnetic tweezers

    NARCIS (Netherlands)

    van Oene, M.M.; Dickinson, L.E.; Cross, B.; Pedaci, F.; Lipfert, J.; Dekker, N.H.

    2017-01-01

    The bacterial flagellar motor of Escherichia coli is a nanoscale rotary engine essential for bacterial propulsion. Studies on the power output of single motors rely on the measurement of motor torque and rotation under external load. Here, we investigate the use of magnetic tweezers, which in

  9. Bundling of elastic filaments induced by hydrodynamic interactions

    Science.gov (United States)

    Man, Yi; Page, William; Poole, Robert J.; Lauga, Eric

    2017-12-01

    Peritrichous bacteria swim in viscous fluids by rotating multiple helical flagellar filaments. As the bacterium swims forward, all its flagella rotate in synchrony behind the cell in a tight helical bundle. When the bacterium changes its direction, the flagellar filaments unbundle and randomly reorient the cell for a short period of time before returning to their bundled state and resuming swimming. This rapid bundling and unbundling is, at its heart, a mechanical process whereby hydrodynamic interactions balance with elasticity to determine the time-varying deformation of the filaments. Inspired by this biophysical problem, we present in this paper what is perhaps the simplest model of bundling whereby two or more straight elastic filaments immersed in a viscous fluid rotate about their centerline, inducing rotational flows which tend to bend the filaments around each other. We derive an integrodifferential equation governing the shape of the filaments resulting from mechanical balance in a viscous fluid at low Reynolds number. We show that such equation may be evaluated asymptotically analytically in the long-wavelength limit, leading to a local partial differential equation governed by a single dimensionless bundling number. A numerical study of the dynamics predicted by the model reveals the presence of two configuration instabilities with increasing bundling numbers: first to a crossing state where filaments touch at one point and then to a bundled state where filaments wrap along each other in a helical fashion. We also consider the case of multiple filaments and the unbundling dynamics. We next provide an intuitive physical model for the crossing instability and show that it may be used to predict analytically its threshold and adapted to address the transition to a bundling state. We then use a macroscale experimental implementation of the two-filament configuration in order to validate our theoretical predictions and obtain excellent agreement. This long

  10. Flagellar glycosylation in Clostridium botulinum.

    Science.gov (United States)

    Twine, Susan M; Paul, Catherine J; Vinogradov, Evgeny; McNally, David J; Brisson, Jean-Robert; Mullen, James A; McMullin, David R; Jarrell, Harold C; Austin, John W; Kelly, John F; Logan, Susan M

    2008-09-01

    Flagellins from Clostridium botulinum were shown to be post-translationally modified with novel glycan moieties by top-down MS analysis of purified flagellin protein from strains of various toxin serotypes. Detailed analyses of flagellin from two strains of C. botulinum demonstrated that the protein is modified by a novel glycan moiety of mass 417 Da in O-linkage. Bioinformatic analysis of available C. botulinum genomes identified a flagellar glycosylation island containing homologs of genes recently identified in Campylobacter coli that have been shown to be responsible for the biosynthesis of legionaminic acid derivatives. Structural characterization of the carbohydrate moiety was completed utilizing both MS and NMR spectroscopy, and it was shown to be a novel legionaminic acid derivative, 7-acetamido-5-(N-methyl-glutam-4-yl)-amino-3,5,7,9-tetradeoxy-D-glycero-alpha-D-galacto-nonulosonic acid, (alphaLeg5GluNMe7Ac). Electron transfer dissociation MS with and without collision-activated dissociation was utilized to map seven sites of O-linked glycosylation, eliminating the need for chemical derivatization of tryptic peptides prior to analysis. Marker ions for novel glycans, as well as a unique C-terminal flagellin peptide marker ion, were identified in a top-down analysis of the intact protein. These ions have the potential for use in for rapid detection and discrimination of C. botulinum cells, indicating botulinum neurotoxin contamination. This is the first report of glycosylation of Gram-positive flagellar proteins by the 'sialic acid-like' nonulosonate sugar, legionaminic acid.

  11. Flagellar Synchronization Is a Simple Alternative to Cell Cycle Synchronization for Ciliary and Flagellar Studies.

    Science.gov (United States)

    Dutta, Soumita; Avasthi, Prachee

    2017-01-01

    The unicellular green alga Chlamydomonas reinhardtii is an ideal model organism for studies of ciliary function and assembly. In assays for biological and biochemical effects of various factors on flagellar structure and function, synchronous culture is advantageous for minimizing variability. Here, we have characterized a method in which 100% synchronization is achieved with respect to flagellar length but not with respect to the cell cycle. The method requires inducing flagellar regeneration by amputation of the entire cell population and limiting regeneration time. This results in a maximally homogeneous distribution of flagellar lengths at 3 h postamputation. We found that time-limiting new protein synthesis during flagellar synchronization limits variability in the unassembled pool of limiting flagellar protein and variability in flagellar length without affecting the range of cell volumes. We also found that long- and short-flagella mutants that regenerate normally require longer and shorter synchronization times, respectively. By minimizing flagellar length variability using a simple method requiring only hours and no changes in media, flagellar synchronization facilitates the detection of small changes in flagellar length resulting from both chemical and genetic perturbations in Chlamydomonas . This method increases our ability to probe the basic biology of ciliary size regulation and related disease etiologies. IMPORTANCE Cilia and flagella are highly conserved antenna-like organelles that found in nearly all mammalian cell types. They perform sensory and motile functions contributing to numerous physiological and developmental processes. Defects in their assembly and function are implicated in a wide range of human diseases ranging from retinal degeneration to cancer. Chlamydomonas reinhardtii is an algal model system for studying mammalian cilium formation and function. Here, we report a simple synchronization method that allows detection of small

  12. In Vitro Reconstitution of Functional Type III Protein Export and Insights into Flagellar Assembly.

    Science.gov (United States)

    Terashima, Hiroyuki; Kawamoto, Akihiro; Tatsumi, Chinatsu; Namba, Keiichi; Minamino, Tohru; Imada, Katsumi

    2018-06-26

    The type III secretion system (T3SS) forms the functional core of injectisomes, protein transporters that allow bacteria to deliver virulence factors into their hosts for infection, and flagella, which are critical for many pathogens to reach the site of infection. In spite of intensive genetic and biochemical studies, the T3SS protein export mechanism remains unclear due to the difficulty of accurate measurement of protein export in vivo Here, we developed an in vitro flagellar T3S protein transport assay system using an inverted cytoplasmic membrane vesicle (IMV) for accurate and controlled measurements of flagellar protein export. We show that the flagellar T3SS in the IMV fully retains export activity. The flagellar hook was constructed inside the lumen of the IMV by adding purified component proteins externally to the IMV solution. We reproduced the hook length control and export specificity switch in the IMV consistent with that seen in the native cell. Previous in vivo analyses showed that flagellar protein export is driven by proton motive force (PMF) and facilitated by ATP hydrolysis by FliI, a T3SS-specific ATPase. Our in vitro assay recapitulated these previous in vivo observations but furthermore clearly demonstrated that even ATP hydrolysis by FliI alone can drive flagellar protein export. Moreover, this assay showed that addition of the FliH 2 /FliI complex to the assay solution at a concentration similar to that in the cell dramatically enhanced protein export, confirming that the FliH 2 /FliI complex in the cytoplasm is important for effective protein transport. IMPORTANCE The type III secretion system (T3SS) is the functional core of the injectisome, a bacterial protein transporter used to deliver virulence proteins into host cells, and bacterial flagella, critical for many pathogens. The molecular mechanism of protein transport is still unclear due to difficulties in accurate measurements of protein transport under well-controlled conditions in

  13. Polyelectrolyte bundles

    Energy Technology Data Exchange (ETDEWEB)

    Limbach, H J; Sayar, M; Holm, C [Max-Planck-Institut fuer Polymerforschung, Ackermannweg 10, 55128 Mainz (Germany)

    2004-06-09

    Using extensive molecular dynamics simulations we study the behaviour of polyelectrolytes with hydrophobic side chains, which are known to form cylindrical micelles in aqueous solution. We investigate the stability of such bundles with respect to hydrophobicity, the strength of the electrostatic interaction and the bundle size. We show that for the parameter range relevant for sulfonated poly(para-phenylenes) (PPP) one finds a stable finite bundle size. In a more generic model we also show the influence of the length of the precursor oligomer on the stability of the bundles. We also point out that our model has close similarities to DNA solutions with added condensing agents, hinting at the possibility that the size of DNA aggregates is, under certain circumstances, thermodynamically limited.

  14. Polyelectrolyte bundles

    International Nuclear Information System (INIS)

    Limbach, H J; Sayar, M; Holm, C

    2004-01-01

    Using extensive molecular dynamics simulations we study the behaviour of polyelectrolytes with hydrophobic side chains, which are known to form cylindrical micelles in aqueous solution. We investigate the stability of such bundles with respect to hydrophobicity, the strength of the electrostatic interaction and the bundle size. We show that for the parameter range relevant for sulfonated poly(para-phenylenes) (PPP) one finds a stable finite bundle size. In a more generic model we also show the influence of the length of the precursor oligomer on the stability of the bundles. We also point out that our model has close similarities to DNA solutions with added condensing agents, hinting at the possibility that the size of DNA aggregates is, under certain circumstances, thermodynamically limited

  15. Polyelectrolyte bundles

    Science.gov (United States)

    Limbach, H. J.; Sayar, M.; Holm, C.

    2004-06-01

    Using extensive Molecular Dynamics simulations we study the behavior of polyelectrolytes with hydrophobic side chains, which are known to form cylindrical micelles in aqueous solution. We investigate the stability of such bundles with respect to hydrophobicity, the strength of the electrostatic interaction, and the bundle size. We show that for the parameter range relevant for sulfonated poly-para-phenylenes (PPP) one finds a stable finite bundle size. In a more generic model we also show the influence of the length of the precursor oligomer on the stability of the bundles. We also point out that our model has close similarities to DNA solutions with added condensing agents, hinting to the possibility that the size of DNA aggregates is under certain circumstances thermodynamically limited.

  16. Bacteria exploit a polymorphic instability of the flagellar filament to escape from traps.

    Science.gov (United States)

    Kühn, Marco J; Schmidt, Felix K; Eckhardt, Bruno; Thormann, Kai M

    2017-06-13

    Many bacterial species swim by rotating single polar helical flagella. Depending on the direction of rotation, they can swim forward or backward and change directions to move along chemical gradients but also to navigate their obstructed natural environment in soils, sediments, or mucus. When they get stuck, they naturally try to back out, but they can also resort to a radically different flagellar mode, which we discovered here. Using high-speed microscopy, we monitored the swimming behavior of the monopolarly flagellated species Shewanella putrefaciens with fluorescently labeled flagellar filaments at an agarose-glass interface. We show that, when a cell gets stuck, the polar flagellar filament executes a polymorphic change into a spiral-like form that wraps around the cell body in a spiral-like fashion and enables the cell to escape by a screw-like backward motion. Microscopy and modeling suggest that this propagation mode is triggered by an instability of the flagellum under reversal of the rotation and the applied torque. The switch is reversible and bacteria that have escaped the trap can return to their normal swimming mode by another reversal of motor direction. The screw-type flagellar arrangement enables a unique mode of propagation and, given the large number of polarly flagellated bacteria, we expect it to be a common and widespread escape or motility mode in complex and structured environments.

  17. Kinematics of flagellar swimming in Euglena gracilis: Helical trajectories and flagellar shapes.

    Science.gov (United States)

    Rossi, Massimiliano; Cicconofri, Giancarlo; Beran, Alfred; Noselli, Giovanni; DeSimone, Antonio

    2017-12-12

    The flagellar swimming of euglenids, which are propelled by a single anterior flagellum, is characterized by a generalized helical motion. The 3D nature of this swimming motion, which lacks some of the symmetries enjoyed by more common model systems, and the complex flagellar beating shapes that power it make its quantitative description challenging. In this work, we provide a quantitative, 3D, highly resolved reconstruction of the swimming trajectories and flagellar shapes of specimens of Euglena gracilis We achieved this task by using high-speed 2D image recordings taken with a conventional inverted microscope combined with a precise characterization of the helical motion of the cell body to lift the 2D data to 3D trajectories. The propulsion mechanism is discussed. Our results constitute a basis for future biophysical research on a relatively unexplored type of eukaryotic flagellar movement. Copyright © 2017 the Author(s). Published by PNAS.

  18. The pH dependence of polymerization and bundling by the essential bacterial cytoskeletal protein FtsZ.

    Directory of Open Access Journals (Sweden)

    Raúl Pacheco-Gómez

    Full Text Available There is a growing body of evidence that bacterial cell division is an intricate coordinated process of comparable complexity to that seen in eukaryotic cells. The dynamic assembly of Escherichia coli FtsZ in the presence of GTP is fundamental to its activity. FtsZ polymerization is a very attractive target for novel antibiotics given its fundamental and universal function. In this study our aim was to understand further the GTP-dependent FtsZ polymerization mechanism and our main focus is on the pH dependence of its behaviour. A key feature of this work is the use of linear dichroism (LD to follow the polymerization of FtsZ monomers into polymeric structures. LD is the differential absorption of light polarized parallel and perpendicular to an orientation direction (in this case that provided by shear flow. It thus readily distinguishes between FtsZ polymers and monomers. It also distinguishes FtsZ polymers and less well-defined aggregates, which light scattering methodologies do not. The polymerization of FtsZ over a range of pHs was studied by right-angled light scattering to probe mass of FtsZ structures, LD to probe real-time formation of linear polymeric fibres, a specially developed phosphate release assay to relate guanosine triphosphate (GTP hydrolysis to polymer formation, and electron microscopy (EM imaging of reaction products as a function of time and pH. We have found that lowering the pH from neutral to 6.5 does not change the nature of the FtsZ polymers in solution--it simply facilitates the polymerization so the fibres present are longer and more abundant. Conversely, lowering the pH to 6.0 has much the same effect as introducing divalent cations or the FtsZ-associated protein YgfE (a putative ZapA orthologue in E. coli--it stabilizes associations of protofilaments.

  19. Bio-hybrid micro/nanodevices powered by flagellar motor: challenges and strategies

    Directory of Open Access Journals (Sweden)

    Jin-Woo eKim

    2015-07-01

    Full Text Available Molecular motors, which are precision-engineered by nature, offer exciting possibilities for bio-hybrid engineered systems. They could enable real applications ranging from micro/nano fluidics, to biosensing, to medical diagnoses. This review describes the fundamental biological insights and fascinating potentials of these remarkable sensing and actuation machines, in particular bacterial flagellar motors, as well as their engineering perspectives with regard to applications in bio-engineered hybrid systems and nanobiotechnology.

  20. Inactivation of ferric uptake regulator (Fur) attenuates Helicobacter pylori J99 motility by disturbing the flagellar motor switch and autoinducer-2 production.

    Science.gov (United States)

    Lee, Ai-Yun; Kao, Cheng-Yen; Wang, Yao-Kuan; Lin, Ssu-Yuan; Lai, Tze-Ying; Sheu, Bor-Shyang; Lo, Chien-Jung; Wu, Jiunn-Jong

    2017-08-01

    Flagellar motility of Helicobacter pylori has been shown to be important for the bacteria to establish initial colonization. The ferric uptake regulator (Fur) is a global regulator that has been identified in H. pylori which is involved in the processes of iron uptake and establishing colonization. However, the role of Fur in H. pylori motility is still unclear. Motility of the wild-type, fur mutant, and fur revertant J99 were determined by a soft-agar motility assay and direct video observation. The bacterial shape and flagellar structure were evaluated by transmission electron microscopy. Single bacterial motility and flagellar switching were observed by phase-contrast microscopy. Autoinducer-2 (AI-2) production in bacterial culture supernatant was analyzed by a bioluminescence assay. The fur mutant showed impaired motility in the soft-agar assay compared with the wild-type J99 and fur revertant. The numbers and lengths of flagellar filaments on the fur mutant cells were similar to those of the wild-type and revertant cells. Phenotypic characterization showed similar swimming speed but reduction in switching rate in the fur mutant. The AI-2 production of the fur mutant was dramatically reduced compared with wild-type J99 in log-phase culture medium. These results indicate that Fur positively modulates H. pylori J99 motility through interfering with bacterial flagellar switching. © 2017 John Wiley & Sons Ltd.

  1. Slipping slender bodies and enhanced flagellar locomotion

    Science.gov (United States)

    Man, Yi; Lauga, Eric

    2017-11-01

    In the biological world, many cells exploit slender appendages to swim, include numerous species of bacteria, algae and spermatozoa. A classical method to describe the flow field around such appendages is slender-body theory (SBT), which is often used to study flagellar motility in Newtonian fluids. However, biology environments are often rheologically complex due to the presence of polymers. These polymers generically phase-separate near rigid boundaries where low-viscosity fluid layers lead to effective slip on the surface. In this talk, we present an analytical derivation of SBT in the case where the no-slip boundary condition on the appendage is replaced by a Navier slip boundary condition. Our results demonstrate in particular a systematic reduction of the resistance coefficient of the slender filaments in their tangential direction, which leads to enhanced flagellar locomotion.

  2. Flagellar motility confers epiphytic fitness advantages upon Pseudomonas syringae

    International Nuclear Information System (INIS)

    Haefele, D.M.; Lindow, S.E.

    1987-01-01

    The role of flagellar motility in determining the epiphytic fitness of an ice-nucleation-active strain of Pseudomonas syringae was examined. The loss of flagellar motility reduced the epiphytic fitness of a normally motile P. syringae strain as measured by its growth, survival, and competitive ability on bean leaf surfaces. Equal population sizes of motile parental or nonmotile mutant P. syringae strains were maintained on bean plants for at least 5 days following the inoculation of fully expanded primary leaves. However, when bean seedlings were inoculated before the primary leaves had expanded and bacterial populations on these leaves were quantified at full expansion, the population size of the nonmotile derivative strain reached only 0.9% that of either the motile parental or revertant strain. When fully expanded bean primary leaves were coinoculated with equal numbers of motile and nonmotile cells, the population size of a nonmotile derivative strain was one-third of that of the motile parental or revertant strain after 8 days. Motile and nonmotile cells were exposed in vitro and on plants to UV radiation and desiccating conditions. The motile and nonmotile strains exhibited equal resistance to both stresses in vitro. However, the population size of a nonmotile strain on leaves was less than 20% that of a motile revertant strain when sampled immediately after UV irradiation. Epiphytic populations of both motile and nonmotile P. syringae declined under desiccating conditions on plants, and after 8 days, the population size of a nonmotile strain was less than one-third that of the motile parental or revertant strain

  3. Flagellar Motility of Trypanosoma cruzi Epimastigotes

    Directory of Open Access Journals (Sweden)

    G. Ballesteros-Rodea

    2012-01-01

    Full Text Available The hemoflagellate Trypanosoma cruzi is the causative agent of American trypanosomiasis. Despite the importance of motility in the parasite life cycle, little is known about T. cruzi motility, and there is no quantitative description of its flagellar beating. Using video microscopy and quantitative vectorial analysis of epimastigote trajectories, we find a forward parasite motility defined by tip-to-base symmetrical flagellar beats. This motion is occasionally interrupted by base-to-tip highly asymmetric beats, which represent the ciliary beat of trypanosomatid flagella. The switch between flagellar and ciliary beating facilitates the parasite's reorientation, which produces a large variability of movement and trajectories that results in different distance ranges traveled by the cells. An analysis of the distance, speed, and rotational angle indicates that epimastigote movement is not completely random, and the phenomenon is highly dependent on the parasite behavior and is characterized by directed and tumbling parasite motion as well as their combination, resulting in the alternation of rectilinear and intricate motility paths.

  4. Impact of fluorescent protein fusions on the bacterial flagellar motor

    NARCIS (Netherlands)

    Heo, M.; Nord, A. L.; Chamousset, D.; van Rijn, E.; Beaumont, H.J.E.; Pedaci, F.

    2017-01-01

    Fluorescent fusion proteins open a direct and unique window onto protein function. However, they also introduce the risk of perturbation of the function of the native protein. Successful applications of fluorescent fusions therefore rely on a careful assessment and minimization of the side

  5. Tetrameric structure of the flagellar cap protein FliD from Serratia marcescens.

    Science.gov (United States)

    Cho, So Yeon; Song, Wan Seok; Hong, Ho Jeong; Lee, Geun-Shik; Kang, Seung Goo; Ko, Hyun-Jeong; Kim, Pyeung-Hyeun; Yoon, Sung-Il

    2017-07-15

    Bacterial motility is provided by the flagellum. FliD is located at the distal end of the flagellum and plays a key role in the insertion of each flagellin protein at the growing tip of the flagellar filament. Because FliD functions as an oligomer, the determination of the oligomeric state of FliD is critical to understanding the molecular mechanism of FliD-mediated flagellar growth. FliD has been shown to adopt a pentameric or a hexameric structure depending on the bacterial species. Here, we report another distinct oligomeric form of FliD based on structural and biochemical studies. The crystal structures of the D2 and D3 domains of Serratia marcescens FliD (smFliD) were determined in two crystal forms and together revealed that smFliD assembles into a tetrameric architecture that resembles a four-pointed star plate. smFliD tetramerization was also confirmed in solution by cross-linking experiments. Although smFliD oligomerizes in a head-to-tail orientation using a common primary binding interface between the D2 and D3' domains (the prime denotes the second subunit in the oligomer) similarly to other FliD orthologs, the smFliD tetramer diverges to present a unique secondary D2-D2' binding interface. Our structure-based comparative analysis of FliD suggests that bacteria have developed diverse species-specific oligomeric forms of FliD that range from tetramers to hexamers for flagellar growth. Copyright © 2017 Elsevier Inc. All rights reserved.

  6. Nonabelian bundle 2-gerbes

    OpenAIRE

    Jurco, Branislav

    2009-01-01

    We define 2-crossed module bundle 2-gerbes related to general Lie 2-crossed modules and discuss their properties. A 2-crossed module bundle 2-gerbe over a manifold is defined in terms of a so called 2-crossed module bundle gerbe, which is a crossed module bundle gerbe equipped with an extra sructure. It is shown that string structures can be described and classified using 2-crossed module bundle 2-gerbes.

  7. The Flagellar Regulon of Legionella—A Review

    Science.gov (United States)

    Appelt, Sandra; Heuner, Klaus

    2017-01-01

    The Legionella genus comprises more than 60 species. In particular, Legionella pneumophila is known to cause severe illnesses in humans. Legionellaceae are ubiquitous inhabitants of aquatic environments. Some Legionellaceae are motile and their motility is important to move around in habitats. Motility can be considered as a potential virulence factor as already shown for various human pathogens. The genes of the flagellar system, regulator and structural genes, are structured in hierarchical levels described as the flagellar regulon. Their expression is modulated by various environmental factors. For L. pneumophila it was shown that the expression of genes of the flagellar regulon is modulated by the actual growth phase and temperature. Especially, flagellated Legionella are known to express genes during the transmissive phase of growth that are involved in the expression of virulence traits. It has been demonstrated that the alternative sigma-28 factor is part of the link between virulence expression and motility. In the following review, the structure of the flagellar regulon of L. pneumophila is discussed and compared to other flagellar systems of different Legionella species. Recently, it has been described that Legionella micdadei and Legionella fallonii contain a second putative partial flagellar system. Hence, the report will focus on flagellated and non-flagellated Legionella strains, phylogenetic relationships, the role and function of the alternative sigma factor (FliA) and its anti-sigma-28 factor (FlgM). PMID:29104863

  8. Applying torque to the Escherichia coli flagellar motor using magnetic tweezers

    Science.gov (United States)

    van Oene, Maarten M.; Dickinson, Laura E.; Cross, Bronwen; Pedaci, Francesco; Lipfert, Jan; Dekker, Nynke H.

    2017-01-01

    The bacterial flagellar motor of Escherichia coli is a nanoscale rotary engine essential for bacterial propulsion. Studies on the power output of single motors rely on the measurement of motor torque and rotation under external load. Here, we investigate the use of magnetic tweezers, which in principle allow the application and active control of a calibrated load torque, to study single flagellar motors in Escherichia coli. We manipulate the external load on the motor by adjusting the magnetic field experienced by a magnetic bead linked to the motor, and we probe the motor’s response. A simple model describes the average motor speed over the entire range of applied fields. We extract the motor torque at stall and find it to be similar to the motor torque at drag-limited speed. In addition, use of the magnetic tweezers allows us to force motor rotation in both forward and backward directions. We monitor the motor’s performance before and after periods of forced rotation and observe no destructive effects on the motor. Our experiments show how magnetic tweezers can provide active and fast control of the external load while also exposing remaining challenges in calibration. Through their non-invasive character and straightforward parallelization, magnetic tweezers provide an attractive platform to study nanoscale rotary motors at the single-motor level. PMID:28266562

  9. The MogR Transcriptional Repressor Regulates Nonhierarchal Expression of Flagellar Motility Genes and Virulence in Listeria monocytogenes.

    Directory of Open Access Journals (Sweden)

    2006-04-01

    Full Text Available Flagella are surface structures critical for motility and virulence of many bacterial species. In Listeria monocytogenes, MogR tightly represses expression of flagellin (FlaA during extracellular growth at 37 degrees C and during intracellular infection. MogR is also required for full virulence in a murine model of infection. Using in vitro and in vivo infection models, we determined that the severe virulence defect of MogR-negative bacteria is due to overexpression of FlaA. Specifically, overproduction of FlaA in MogR-negative bacteria caused pleiotropic defects in bacterial division (chaining phenotype, intracellular spread, and virulence in mice. DNA binding and microarray analyses revealed that MogR represses transcription of all known flagellar motility genes by binding directly to a minimum of two TTTT-N(5-AAAA recognition sites positioned within promoter regions such that RNA polymerase binding is occluded. Analysis of MogR protein levels demonstrated that modulation of MogR repression activity confers the temperature-specificity to flagellar motility gene expression. Epistasis analysis revealed that MogR repression of transcription is antagonized in a temperature-dependent manner by the DegU response regulator and that DegU further regulates FlaA levels through a posttranscriptional mechanism. These studies provide the first known example to our knowledge of a transcriptional repressor functioning as a master regulator controlling nonhierarchal expression of flagellar motility genes.

  10. Strategic Aspects of Bundling

    International Nuclear Information System (INIS)

    Podesta, Marion

    2008-01-01

    The increase of bundle supply has become widespread in several sectors (for instance in telecommunications and energy fields). This paper review relates strategic aspects of bundling. The main purpose of this paper is to analyze profitability of bundling strategies according to the degree of competition and the characteristics of goods. Moreover, bundling can be used as price discrimination tool, screening device or entry barriers. In monopoly case bundling strategy is efficient to sort consumers in different categories in order to capture a maximum of surplus. However, when competition increases, the profitability on bundling strategies depends on correlation of consumers' reservations values. (author)

  11. Design of a Comprehensive Biochemistry and Molecular Biology Experiment: Phase Variation Caused by Recombinational Regulation of Bacterial Gene Expression

    Science.gov (United States)

    Sheng, Xiumei; Xu, Shungao; Lu, Renyun; Isaac, Dadzie; Zhang, Xueyi; Zhang, Haifang; Wang, Huifang; Qiao, Zheng; Huang, Xinxiang

    2014-01-01

    Scientific experiments are indispensable parts of Biochemistry and Molecular Biology. In this study, a comprehensive Biochemistry and Molecular Biology experiment about "Salmonella enterica" serovar Typhi Flagellar phase variation has been designed. It consisted of three parts, namely, inducement of bacterial Flagellar phase variation,…

  12. Nonlinear amplitude dynamics in flagellar beating.

    Science.gov (United States)

    Oriola, David; Gadêlha, Hermes; Casademunt, Jaume

    2017-03-01

    The physical basis of flagellar and ciliary beating is a major problem in biology which is still far from completely understood. The fundamental cytoskeleton structure of cilia and flagella is the axoneme, a cylindrical array of microtubule doublets connected by passive cross-linkers and dynein motor proteins. The complex interplay of these elements leads to the generation of self-organized bending waves. Although many mathematical models have been proposed to understand this process, few attempts have been made to assess the role of dyneins on the nonlinear nature of the axoneme. Here, we investigate the nonlinear dynamics of flagella by considering an axonemal sliding control mechanism for dynein activity. This approach unveils the nonlinear selection of the oscillation amplitudes, which are typically either missed or prescribed in mathematical models. The explicit set of nonlinear equations are derived and solved numerically. Our analysis reveals the spatio-temporal dynamics of dynein populations and flagellum shape for different regimes of motor activity, medium viscosity and flagellum elasticity. Unstable modes saturate via the coupling of dynein kinetics and flagellum shape without the need of invoking a nonlinear axonemal response. Hence, our work reveals a novel mechanism for the saturation of unstable modes in axonemal beating.

  13. Bundle Branch Block

    Science.gov (United States)

    ... known cause. Causes can include: Left bundle branch block Heart attacks (myocardial infarction) Thickened, stiffened or weakened ... myocarditis) High blood pressure (hypertension) Right bundle branch block A heart abnormality that's present at birth (congenital) — ...

  14. In situ ellipsometric study of surface immobilization of flagellar filaments

    Energy Technology Data Exchange (ETDEWEB)

    Kurunczi, S., E-mail: kurunczi@mfa.kfki.hu [Department of Photonics, Research Institute for Technical Physics and Materials Science, H-1121, Konkoly Thege Miklos ut 29-33, Budapest (Hungary); Nemeth, A.; Huelber, T. [Department of Photonics, Research Institute for Technical Physics and Materials Science, H-1121, Konkoly Thege Miklos ut 29-33, Budapest (Hungary); Kozma, P. [Department of Photonics, Research Institute for Technical Physics and Materials Science, H-1121, Konkoly Thege Miklos ut 29-33, Budapest (Hungary); Department of Nanotechnology, Research Institute of Chemical and Process Engineering, Faculty of Information Technology, University of Pannonia, Egyetem u. 10, Veszprem, H-8200 (Hungary); Petrik, P. [Department of Photonics, Research Institute for Technical Physics and Materials Science, H-1121, Konkoly Thege Miklos ut 29-33, Budapest (Hungary); Jankovics, H. [Department of Nanotechnology, Research Institute of Chemical and Process Engineering, Faculty of Information Technology, University of Pannonia, Egyetem u. 10, Veszprem, H-8200 (Hungary); Sebestyen, A. [Department of Photonics, Research Institute for Technical Physics and Materials Science, H-1121, Konkoly Thege Miklos ut 29-33, Budapest (Hungary); Department of Nanotechnology, Research Institute of Chemical and Process Engineering, Faculty of Information Technology, University of Pannonia, Egyetem u. 10, Veszprem, H-8200 (Hungary); Vonderviszt, F. [Department of Photonics, Research Institute for Technical Physics and Materials Science, H-1121, Konkoly Thege Miklos ut 29-33, Budapest (Hungary); Department of Nanotechnology, Research Institute of Chemical and Process Engineering, Faculty of Information Technology, University of Pannonia, Egyetem u. 10, Veszprem, H-8200 (Hungary); Institute of Enzymology, Karolina ut 29-33, Budapest, H-1113 (Hungary); and others

    2010-10-15

    Protein filaments composed of thousands of subunits are promising candidates as sensing elements in biosensors. In this work in situ spectroscopic ellipsometry is applied to monitor the surface immobilization of flagellar filaments. This study is the first step towards the development of layers of filamentous receptors for sensor applications. Surface activation is performed using silanization and a subsequent glutaraldehyde crosslinking. Structure of the flagellar filament layers immobilized on activated and non-activated Si wafer substrates is determined using a two-layer effective medium model that accounted for the vertical density distribution of flagellar filaments with lengths of 300-1500 nm bound to the surface. The formation of the first interface layer can be explained by the multipoint covalent attachment of the filaments, while the second layer is mainly composed of tail pinned filaments floating upwards with the free parts. As confirmed by atomic force microscopy, covalent immobilization resulted in an increased surface density compared to absorption.

  15. Polycation induced actin bundles

    OpenAIRE

    Muhlrad, Andras; Grintsevich, Elena E.; Reisler, Emil

    2011-01-01

    Three polycations, polylysine, the polyamine spermine and the polycationic protein lysozyme were used to study the formation, structure, ionic strength sensitivity and dissociation of polycation-induced actin bundles. Bundles form fast, simultaneously with the polymerization of MgATP-G-actins, upon addition of polycations to solutions of actins at low ionic strength conditions. This indicates that nuclei and/or nascent filaments bundle due to attractive, electrostatic effect of polycations an...

  16. Polycation induced actin bundles.

    Science.gov (United States)

    Muhlrad, Andras; Grintsevich, Elena E; Reisler, Emil

    2011-04-01

    Three polycations, polylysine, the polyamine spermine and the polycationic protein lysozyme were used to study the formation, structure, ionic strength sensitivity and dissociation of polycation-induced actin bundles. Bundles form fast, simultaneously with the polymerization of MgATP-G-actins, upon the addition of polycations to solutions of actins at low ionic strength conditions. This indicates that nuclei and/or nascent filaments bundle due to attractive, electrostatic effect of polycations and the neutralization of repulsive interactions of negative charges on actin. The attractive forces between the filaments are strong, as shown by the low (in nanomolar range) critical concentration of their bundling at low ionic strength. These bundles are sensitive to ionic strength and disassemble partially in 100 mM NaCl, but both the dissociation and ionic strength sensitivity can be countered by higher polycation concentrations. Cys374 residues of actin monomers residing on neighboring filaments in the bundles can be cross-linked by the short span (5.4Å) MTS-1 (1,1-methanedyl bismethanethiosulfonate) cross-linker, which indicates a tight packing of filaments in the bundles. The interfilament cross-links, which connect monomers located on oppositely oriented filaments, prevent disassembly of bundles at high ionic strength. Cofilin and the polysaccharide polyanion heparin disassemble lysozyme induced actin bundles more effectively than the polylysine-induced bundles. The actin-lysozyme bundles are pathologically significant as both proteins are found in the pulmonary airways of cystic fibrosis patients. Their bundles contribute to the formation of viscous mucus, which is the main cause of breathing difficulties and eventual death in this disorder. Copyright © 2011 Elsevier B.V. All rights reserved.

  17. Principal noncommutative torus bundles

    DEFF Research Database (Denmark)

    Echterhoff, Siegfried; Nest, Ryszard; Oyono-Oyono, Herve

    2008-01-01

    of bivariant K-theory (denoted RKK-theory) due to Kasparov. Using earlier results of Echterhoff and Williams, we shall give a complete classification of principal non-commutative torus bundles up to equivariant Morita equivalence. We then study these bundles as topological fibrations (forgetting the group...

  18. Human sperm steer with second harmonics of the flagellar beat.

    Science.gov (United States)

    Saggiorato, Guglielmo; Alvarez, Luis; Jikeli, Jan F; Kaupp, U Benjamin; Gompper, Gerhard; Elgeti, Jens

    2017-11-10

    Sperm are propelled by bending waves traveling along their flagellum. For steering in gradients of sensory cues, sperm adjust the flagellar waveform. Symmetric and asymmetric waveforms result in straight and curved swimming paths, respectively. Two mechanisms causing spatially asymmetric waveforms have been proposed: an average flagellar curvature and buckling. We image flagella of human sperm tethered with the head to a surface. The waveform is characterized by a fundamental beat frequency and its second harmonic. The superposition of harmonics breaks the beat symmetry temporally rather than spatially. As a result, sperm rotate around the tethering point. The rotation velocity is determined by the second-harmonic amplitude and phase. Stimulation with the female sex hormone progesterone enhances the second-harmonic contribution and, thereby, modulates sperm rotation. Higher beat frequency components exist in other flagellated cells; therefore, this steering mechanism might be widespread and could inspire the design of synthetic microswimmers.

  19. Vibration of fuel bundles

    International Nuclear Information System (INIS)

    Chen, S.S.

    1975-06-01

    Several mathematical models have been proposed for calculating fuel rod responses in axial flows based on a single rod consideration. The spacing between fuel rods in liquid metal fast breeder reactors is small; hence fuel rods will interact with one another due to fluid coupling. The objective of this paper is to study the coupled vibration of fuel bundles. To account for the fluid coupling, a computer code, AMASS, is developed to calculate added mass coefficients for a group of circular cylinders based on the potential flow theory. The equations of motion for rod bundles are then derived including hydrodynamic forces, drag forces, fluid pressure, gravity effect, axial tension, and damping. Based on the equations, a method of analysis is presented to study the free and forced vibrations of rod bundles. Finally, the method is applied to a typical LMFBR fuel bundle consisting of seven rods

  20. Identification and characterization of a stage specific membrane protein involved in flagellar attachment in Trypanosoma brucei.

    Directory of Open Access Journals (Sweden)

    Katherine Woods

    Full Text Available Flagellar attachment is a visibly striking morphological feature of African trypanosomes but little is known about the requirements for attachment at a molecular level. This study characterizes a previously undescribed membrane protein, FLA3, which plays an essential role in flagellar attachment in Trypanosoma brucei. FLA3 is heavily N-glycosylated, locates to the flagellar attachment zone and appears to be a bloodstream stage specific protein. Ablation of the FLA3 mRNA rapidly led to flagellar detachment and a concomitant failure of cytokinesis in the long slender bloodstream form but had no effect on the procyclic form. Flagellar detachment was obvious shortly after induction of the dsRNA and the newly synthesized flagellum was often completely detached after it emerged from the flagellar pocket. Within 12 h most cells possessed detached flagella alongside the existing attached flagellum. These results suggest that proteins involved in attachment are not shared between the new and old attachment zones. In other respects the detached flagella appear normal, they beat rapidly although directional motion was lost, and they possess an apparently normal axoneme and paraflagellar rod structure. The flagellar attachment zone appeared to be disrupted when FLA3 was depleted. Thus, while flagellar attachment is a constitutive feature of the life cycle of trypanosomes, attachment requires stage specific elements at the protein level.

  1. Second-chance signal transduction explains cooperative flagellar switching.

    Science.gov (United States)

    Zot, Henry G; Hasbun, Javier E; Minh, Nguyen Van

    2012-01-01

    The reversal of flagellar motion (switching) results from the interaction between a switch complex of the flagellar rotor and a torque-generating stationary unit, or stator (motor unit). To explain the steeply cooperative ligand-induced switching, present models propose allosteric interactions between subunits of the rotor, but do not address the possibility of a reaction that stimulates a bidirectional motor unit to reverse direction of torque. During flagellar motion, the binding of a ligand-bound switch complex at the dwell site could excite a motor unit. The probability that another switch complex of the rotor, moving according to steady-state rotation, will reach the same dwell site before that motor unit returns to ground state will be determined by the independent decay rate of the excited-state motor unit. Here, we derive an analytical expression for the energy coupling between a switch complex and a motor unit of the stator complex of a flagellum, and demonstrate that this model accounts for the cooperative switching response without the need for allosteric interactions. The analytical result can be reproduced by simulation when (1) the motion of the rotor delivers a subsequent ligand-bound switch to the excited motor unit, thereby providing the excited motor unit with a second chance to remain excited, and (2) the outputs from multiple independent motor units are constrained to a single all-or-none event. In this proposed model, a motor unit and switch complex represent the components of a mathematically defined signal transduction mechanism in which energy coupling is driven by steady-state and is regulated by stochastic ligand binding. Mathematical derivation of the model shows the analytical function to be a general form of the Hill equation (Hill AV (1910) The possible effects of the aggregation of the molecules of haemoglobin on its dissociation curves. J Physiol 40: iv-vii).

  2. Flow in rod bundles

    International Nuclear Information System (INIS)

    Hazi, G.; Mayer, G.

    2005-01-01

    For power upgrading VVER-440 reactors we need to know exactly how the temperature measured by the thermocouples is related to the average outlet temperature of the fuel assemblies. Accordingly, detailed knowledge on mixing process in the rod bundles and in the fuel assembly head have great importance. Here we study the hydrodynamics of rod bundles based on the results of direct numerical and large eddy simulation of flows in subchannels. It is shown that secondary flow and flow pulsation phenomena can be observed using both methodologies. Some consequences of these observations are briefly discussed. (author)

  3. Standard-model bundles

    CERN Document Server

    Donagi, Ron; Pantev, Tony; Waldram, Dan; Donagi, Ron; Ovrut, Burt; Pantev, Tony; Waldram, Dan

    2002-01-01

    We describe a family of genus one fibered Calabi-Yau threefolds with fundamental group ${\\mathbb Z}/2$. On each Calabi-Yau $Z$ in the family we exhibit a positive dimensional family of Mumford stable bundles whose symmetry group is the Standard Model group $SU(3)\\times SU(2)\\times U(1)$ and which have $c_{3} = 6$. We also show that for each bundle $V$ in our family, $c_{2}(Z) - c_{2}(V)$ is the class of an effective curve on $Z$. These conditions ensure that $Z$ and $V$ can be used for a phenomenologically relevant compactification of Heterotic M-theory.

  4. Irradiated fuel bundle counter

    International Nuclear Information System (INIS)

    Campbell, J.W.; Todd, J.L.

    1975-01-01

    The design of a prototype safeguards instrument for determining the number of irradiated fuel assemblies leaving an on-power refueled reactor is described. Design details include radiation detection techniques, data processing and display, unattended operation capabilities and data security methods. Development and operating history of the bundle counter is reported. (U.S.)

  5. Irradiated fuel bundle counter

    International Nuclear Information System (INIS)

    Campbell, J.W.; Todd, J.L.

    1975-01-01

    The design of a prototype safeguards instrument for determining the number of irradiated fuel assemblies leaving an on-power refueled reactor is described. Design details include radiation detection techniques, data processing and display, unattended operation capabilities and data security methods. Development and operating history of the bundle counter is reported

  6. ALUMINUM BOX BUNDLING PRESS

    Directory of Open Access Journals (Sweden)

    Iosif DUMITRESCU

    2015-05-01

    Full Text Available In municipal solid waste, aluminum is the main nonferrous metal, approximately 80- 85% of the total nonferrous metals. The income per ton gained from aluminum recuperation is 20 times higher than from glass, steel boxes or paper recuperation. The object of this paper is the design of a 300 kN press for aluminum box bundling.

  7. Kernel bundle EPDiff

    DEFF Research Database (Denmark)

    Sommer, Stefan Horst; Lauze, Francois Bernard; Nielsen, Mads

    2011-01-01

    In the LDDMM framework, optimal warps for image registration are found as end-points of critical paths for an energy functional, and the EPDiff equations describe the evolution along such paths. The Large Deformation Diffeomorphic Kernel Bundle Mapping (LDDKBM) extension of LDDMM allows scale space...

  8. An Element of Determinism in a Stochastic Flagellar Motor Switch.

    Science.gov (United States)

    Xie, Li; Altindal, Tuba; Wu, Xiao-Lun

    2015-01-01

    Marine bacterium Vibrio alginolyticus uses a single polar flagellum to navigate in an aqueous environment. Similar to Escherichia coli cells, the polar flagellar motor has two states; when the motor is counter-clockwise, the cell swims forward and when the motor is clockwise, the cell swims backward. V. alginolyticus also incorporates a direction randomization step at the start of the forward swimming interval by flicking its flagellum. To gain an understanding on how the polar flagellar motor switch is regulated, distributions of the forward Δf and backward Δb intervals are investigated herein. We found that the steady-state probability density functions, P(Δf) and P(Δb), of freely swimming bacteria are strongly peaked at a finite time, suggesting that the motor switch is not Poissonian. The short-time inhibition is sufficiently strong and long lasting, i.e., several hundred milliseconds for both intervals, which is readily observed and characterized. Treating motor reversal dynamics as a first-passage problem, which results from conformation fluctuations of the motor switch, we calculated P(Δf) and P(Δb) and found good agreement with the measurements.

  9. Flagellar-phase variation: isolation of the rh1 gene

    International Nuclear Information System (INIS)

    Silverman, M.; Zieg, J.; Simon, M.

    1979-01-01

    In Salmonella, expression of flagellar antigen alternates between two serotypes (phases) encoded by two genes, H1 and H2. The mechanism which controls the alternative expression of the H1 and H2 genes was examined by cloning these genes and the genetic elements which control their activity on hybrid vehicles in Escherichia coli. H2 gene activity was shown to be controlled by a recombinational switch located adjacent to the H2 gene. Activity of the H1 gene is thought to be repressed, when the H2 gene is expressed, by the product of another gene, rhl (repressor of H1), which is controlled coordinately with the H2 gene. In this report, we describe the construction of hybrid lambda vehicles which contain, in addition to the H2 gene, a genetic activity corresponding to rhl. Variation of flagellar antigens analogous to that observed in Salmonella was observed when E. coli strains were transduced with the hybrid lambda. By using the lambda H2rhl hybrid to program protein syntheis in uv-irradiated cells, the synthesis of a polypeptide was correlated with rhl gene product activity. We conclude that the H2 region consists of two cotranscribed genes, H2 and rhl. The expression of both gene products is regulated by the same recombinational event

  10. Impaired competence in flagellar mutants of Bacillus subtilis is connected to the regulatory network governed by DegU

    DEFF Research Database (Denmark)

    Hölscher, Theresa; Schiklang, Tina; Dragos, Anna

    2018-01-01

    The competent state is a developmentally distinct phase, in which bacteria are able to take up and integrate exogenous DNA into their genome. Bacillus subtilis is one of the naturally competent bacterial species and the domesticated laboratory strain 168 is easily transformable. In this study, we...... report a reduced transformation frequency of B. subtilis mutants lacking functional and structural flagellar components. This includes hag, the gene encoding the flagellin protein forming the filament of the flagellum. We confirm that the observed decrease of the transformation frequency is due...... a close link between motility and natural competence in B. subtilis suggesting that hindrance in motility has great impact on differentiation of this bacterium not restricted only to the transition towards sessile growth stage....

  11. Right bundle branch block

    DEFF Research Database (Denmark)

    Bussink, Barbara E; Holst, Anders Gaarsdal; Jespersen, Lasse

    2013-01-01

    AimsTo determine the prevalence, predictors of newly acquired, and the prognostic value of right bundle branch block (RBBB) and incomplete RBBB (IRBBB) on a resting 12-lead electrocardiogram in men and women from the general population.Methods and resultsWe followed 18 441 participants included...... in the Copenhagen City Heart Study examined in 1976-2003 free from previous myocardial infarction (MI), chronic heart failure, and left bundle branch block through registry linkage until 2009 for all-cause mortality and cardiovascular outcomes. The prevalence of RBBB/IRBBB was higher in men (1.4%/4.7% in men vs. 0.......5%/2.3% in women, P block was associated with significantly...

  12. Bundling harvester; Nippukorjausharvesteri

    Energy Technology Data Exchange (ETDEWEB)

    Koponen, K. [Eko-Log Oy, Kuopio (Finland)

    1996-12-31

    The staring point of the project was to design and construct, by taking the silvicultural point of view into account, a harvesting and processing system especially for energy-wood, containing manually driven bundling harvester, automatizing of the harvester, and automatized loading. The equipment forms an ideal method for entrepreneur`s-line harvesting. The target is to apply the system also for owner`s-line harvesting. The profitability of the system promotes the utilization of the system in both cases. The objectives of the project were: to construct a test equipment and prototypes for all the project stages, to carry out terrain and strain tests in order to examine the usability and durability, as well as the capacity of the machine, to test the applicability of the Eko-Log system in simultaneous harvesting of energy and pulp woods, and to start the marketing and manufacturing of the products. The basic problems of the construction of the bundling harvester have been solved using terrain-tests. The prototype machine has been shown to be operable. Loading of the bundles to form sufficiently economically transportable loads has been studied, and simultaneously, the branch-biomass has been tried to be utilized without loosing the profitability of transportation. The results have been promising, and will promote the profitable utilization of wood-energy

  13. Bundling harvester; Nippukorjausharvesteri

    Energy Technology Data Exchange (ETDEWEB)

    Koponen, K [Eko-Log Oy, Kuopio (Finland)

    1997-12-31

    The staring point of the project was to design and construct, by taking the silvicultural point of view into account, a harvesting and processing system especially for energy-wood, containing manually driven bundling harvester, automatizing of the harvester, and automatized loading. The equipment forms an ideal method for entrepreneur`s-line harvesting. The target is to apply the system also for owner`s-line harvesting. The profitability of the system promotes the utilization of the system in both cases. The objectives of the project were: to construct a test equipment and prototypes for all the project stages, to carry out terrain and strain tests in order to examine the usability and durability, as well as the capacity of the machine, to test the applicability of the Eko-Log system in simultaneous harvesting of energy and pulp woods, and to start the marketing and manufacturing of the products. The basic problems of the construction of the bundling harvester have been solved using terrain-tests. The prototype machine has been shown to be operable. Loading of the bundles to form sufficiently economically transportable loads has been studied, and simultaneously, the branch-biomass has been tried to be utilized without loosing the profitability of transportation. The results have been promising, and will promote the profitable utilization of wood-energy

  14. Rab23 is a flagellar protein in Trypanosoma brucei

    Directory of Open Access Journals (Sweden)

    Field Mark C

    2011-06-01

    Full Text Available Abstract Background Rab small GTPases are important mediators of membrane transport, and orthologues frequently retain similar locations and functions, even between highly divergent taxa. In metazoan organisms Rab23 is an important negative regulator of Sonic hedgehog signaling and is crucial for correct development and differentiation of cellular lineages by virtue of an involvement in ciliary recycling. Previously, we reported that Trypanosoma brucei Rab23 localized to the nuclear envelope 1, which is clearly inconsistent with the mammalian location and function. As T. brucei is unicellular the potential that Rab23 has no role in cell signaling was possible. Here we sought to further investigate the role(s of Rab23 in T. brucei to determine if Rab23 was an example of a Rab protein with divergent function in distinct taxa. Methods/major findings The taxonomic distribution of Rab23 was examined and compared with the presence of flagella/cilia in representative taxa. Despite evidence for considerable secondary loss, we found a clear correlation between a conventional flagellar structure and the presence of a Rab23 orthologue in the genome. By epitope-tagging, Rab23 was localized and found to be present at the flagellum throughout the cell cycle. However, RNAi knockdown did not result in a flagellar defect, suggesting that Rab23 is not required for construction or maintenance of the flagellum. Conclusions The location of Rab23 at the flagellum is conserved between mammals and trypanosomes and the Rab23 gene is restricted to flagellated organisms. These data may suggest the presence of a Rab23-mediated signaling mechanism in trypanosomes.

  15. Nonlinear instability in flagellar dynamics: a novel modulation mechanism in sperm migration?

    KAUST Repository

    Gadelha, H.; Gaffney, E. A.; Smith, D. J.; Kirkman-Brown, J. C.

    2010-01-01

    . We study the effect of geometrical nonlinearity, focusing on the spermatozoon flagellum. For a wide range of physiologically relevant parameters, the nonlinear model predicts that flagellar compression by the internal forces initiates an effective

  16. Minimum Information Loss Based Multi-kernel Learning for Flagellar Protein Recognition in Trypanosoma Brucei

    KAUST Repository

    Wang, Jim Jing-Yan; Gao, Xin

    2014-01-01

    for the purposes of both biological research and drug design. In this paper, we investigate computationally recognizing flagellar proteins in T. Brucei by pattern recognition methods. It is argued that an optimal decision function can be obtained as the difference

  17. The Atiyah bundle and connections on a principal bundle

    Indian Academy of Sciences (India)

    be the fiber bundle constructed as in (1.1) for the universal principal G-bundle. In a work in progress, we hope to show that the universal G-connection can be realized as a fiber bundle over C(EG). Turning this ... a G-invariant vector field on EG|U . In other words, we get a bijective linear map between. A(EG)(U) (the space of ...

  18. Managing bundled payments.

    Science.gov (United States)

    Draper, Andrew

    2011-04-01

    Results of Medicare's ACE demonstration project and Geisinger Health System's ProvenCare initiative provide insight into the challenges hospitals will face as bundled payment proliferates. An early analysis of these results suggests that hospitals would benefit from bringing full automation using clinical IT tools to bear in their efforts to meet these challenges. Other important factors contributing to success include board and physician leadership, organizational structure, pricing methodology for bidding, evidence-based medical practice guidelines, supply cost management, process efficiency management, proactive and aggressive case management, business development and marketing strategy, and the financial management system.

  19. Muon bundles from the Universe

    Directory of Open Access Journals (Sweden)

    Kankiewicz P.

    2018-01-01

    Full Text Available Recently the CERN ALICE experiment, in its dedicated cosmic ray run, observed muon bundles of very high multiplicities, thereby confirming similar findings from the LEP era at CERN (in the CosmoLEP project. Significant evidence for anisotropy of arrival directions of the observed high multiplicity muonic bundles is found. Estimated directionality suggests their possible extragalactic provenance. We argue that muonic bundles of highest multiplicity are produced by strangelets, hypothetical stable lumps of strange quark matter infiltrating our Universe.

  20. Infinitesimal bundles and projective relativity

    International Nuclear Information System (INIS)

    Evans, G.T.

    1973-01-01

    An intrinsic and global presentation of five-dimensional relativity theory is developed, in which special coordinate conditions are replaced by conditions of Lie invariance. The notion of an infinitesimal bundle is introduced, and the theory of connexions on principal bundles is extended to infinitesimal bundles. Global aspects of projective relativity are studied: it is shown that projective relativity can describe almost any space-time. In particular, it is not necessary to assume that the electromagnetic field have a global potential. (author)

  1. REBEKA bundle experiments

    International Nuclear Information System (INIS)

    Wiehr, K.

    1988-05-01

    This report is a summary of experimental investigations describing the fuel rod behavior in the refilling and reflooding phase of a loss-of-coolant accident of a PWR. The experiments were performed with 5x5 and 7x7 rod bundles, using indirectly electrically heated fuel rod simulators of full length with original PWR-KWU-geometry, original grid spacers and Zircaloy-4-claddings (Type Biblis B). The fuel rod simulators showed a cosine shaped axial power profile in 7 steps and continuous, respectively. The results describe the influence of the different parameters such as bundle size on the maximum coolant channel blockage, that of the cooling on the size of the circumferential strain of the cladding (azimuthal temperature distribution) a cold control rod guide thimble and the flow direction (axial temperature distribution) on the resulting coolant channel blockage. The rewetting behavior of different fuel rod simulators including ballooned and burst Zircaloy claddings is discussed as well as the influence of thermocouples on the cladding temperature history and the rewetting behavior. All results prove the coolability of a PWR in the case of a LOCA. Therefore, it can be concluded that the ECC-criteria established by licensing authorities can be fulfilled. (orig./HP) [de

  2. Nefness of adjoint bundles for ample vector bundles

    Directory of Open Access Journals (Sweden)

    Hidetoshi Maeda

    1995-11-01

    Full Text Available Let E be an ample vector bundle of rank >1 on a smooth complex projective variety X of dimension n. This paper gives a classification of pairs (X,E whose adjoint bundles K_X+det E are not nef in the case when  r=n-2.

  3. Bundle Security Protocol for ION

    Science.gov (United States)

    Burleigh, Scott C.; Birrane, Edward J.; Krupiarz, Christopher

    2011-01-01

    This software implements bundle authentication, conforming to the Delay-Tolerant Networking (DTN) Internet Draft on Bundle Security Protocol (BSP), for the Interplanetary Overlay Network (ION) implementation of DTN. This is the only implementation of BSP that is integrated with ION.

  4. CANFLEX fuel bundle impact test

    International Nuclear Information System (INIS)

    Chang, Seok Kyu; Chung, C. H.; Park, J. S.; Hong, S. D.; Kim, B. D.

    1997-08-01

    This document outlines the test results for the impact test of the CANFLEX fuel bundle. Impact test is performed to determine and verify the amount of general bundle shape distortion and defect of the pressure tube that may occur during refuelling. The test specification requires that the fuel bundles and the pressure tube retain their integrities after the impact test under the conservative conditions (10 stationary bundles with 31kg/s flow rate) considering the pressure tube creep. The refuelling simulator operating with pneumatic force and simulated shield plug were fabricated and the velocity/displacement transducer and the high speed camera were also used in this test. The characteristics of the moving bundle (velocity, displacement, impacting force) were measured and analyzed with the impact sensor and the high speed camera system. The important test procedures and measurement results were discussed as follows. 1) Test bundle measurements and the pressure tube inspections 2) Simulated shield plug, outlet flange installation and bundle loading 3) refuelling simulator, inlet flange installation and sensors, high speed camera installation 4) Perform the impact test with operating the refuelling simulator and measure the dynamic characteristics 5) Inspections of the fuel bundles and the pressure tube. (author). 8 refs., 23 tabs., 13 figs

  5. Connections on discrete fibre bundles

    International Nuclear Information System (INIS)

    Manton, N.S.; Cambridge Univ.

    1987-01-01

    A new approach to gauge fields on a discrete space-time is proposed, in which the fundamental object is a discrete version of a principal fibre bundle. If the bundle is twisted, the gauge fields are topologically non-trivial automatically. (orig.)

  6. Sasakian and Parabolic Higgs Bundles

    Science.gov (United States)

    Biswas, Indranil; Mj, Mahan

    2018-03-01

    Let M be a quasi-regular compact connected Sasakian manifold, and let N = M/ S 1 be the base projective variety. We establish an equivalence between the class of Sasakian G-Higgs bundles over M and the class of parabolic (or equivalently, ramified) G-Higgs bundles over the base N.

  7. Flagellar region 3b supports strong expression of integrated DNA and the highest chromosomal integration efficiency of the Escherichia coli flagellar regions.

    Science.gov (United States)

    Juhas, Mario; Ajioka, James W

    2015-07-01

    The Gram-negative bacterium Escherichia coli is routinely used as the chassis for a variety of biotechnology and synthetic biology applications. Identification and analysis of reliable chromosomal integration and expression target loci is crucial for E. coli engineering. Chromosomal loci differ significantly in their ability to support integration and expression of the integrated genetic circuits. In this study, we investigate E. coli K12 MG1655 flagellar regions 2 and 3b. Integration of the genetic circuit into seven and nine highly conserved genes of the flagellar regions 2 (motA, motB, flhD, flhE, cheW, cheY and cheZ) and 3b (fliE, F, G, J, K, L, M, P, R), respectively, showed significant variation in their ability to support chromosomal integration and expression of the integrated genetic circuit. While not reducing the growth of the engineered strains, the integrations into all 16 target sites led to the loss of motility. In addition to high expression, the flagellar region 3b supports the highest efficiency of integration of all E. coli K12 MG1655 flagellar regions and is therefore potentially the most suitable for the integration of synthetic genetic circuits. © 2015 The Authors. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.

  8. Twisted Vector Bundles on Pointed Nodal Curves

    Indian Academy of Sciences (India)

    Abstract. Motivated by the quest for a good compactification of the moduli space of -bundles on a nodal curve we establish a striking relationship between Abramovich's and Vistoli's twisted bundles and Gieseker vector bundles.

  9. Changes in the flagellar bundling time account for variations in swimming behavior of flagellated bacteria in viscous media

    NARCIS (Netherlands)

    Qu, Zijie; Temel, Fatma Zeynep; Henderikx, Rene; Breuer, Kenneth S.

    2018-01-01

    Although the motility of the flagellated bacteria, Escherichia coli, has been widely studied, the effect of viscosity on swimming speed remains controversial. The swimming mode of wild-type E. coli is often idealized as a run-and-tumble sequence in which periods of swimming at a constant speed are

  10. Textor bundle divertor

    International Nuclear Information System (INIS)

    Yang, T.F.; Wan, A.; Gierszewski, P.; Rapperport, E.; Montgomery, D.B.

    1982-01-01

    This report presents a preliminary bundle divertor conceptual design for installation on the TEXTOR tokamak. An advanced cascade T-shaped coil configuration is used. This divertor design has the following important characteristics: (1) the current density in the conductor is less than 6 kAmp/cm 2 , and the maximum field is less than 6 Tesla; (2) the divertor can be operated at steady-state either for copper or superconducting conductors; (3) the power consumption is about 7 MW for a normal conductor; (4) the divertor can be inserted into the existing geometry of TEXTOR; (5) the ripple on axis is only 0.3% and the mirror ratio is 2 to 4; (6) the stagnation axis is concave toward the plasma, therefore q/sub D/ is smaller, the acceptance angle is larger, and the efficiency may be better than the conventional circular coil design

  11. TEXTOR bundle divertor

    International Nuclear Information System (INIS)

    Yang, T.F.; Wan, A.; Gierszewski, P.; Rapperport, E.; Montgomery, D.B.

    1982-01-01

    This report presents a preliminary bundle divertor conceptual design for installation on the TEXTOR tokamak. An advanced cascade T-shaped coil configuration is used. This divertor design has the following important characteristics: (1) the current density in the conductor is less than 6 kAmp/cm 2 , and the maximum field is less than 6 Tesla; (2) the divertor can be operated at steady-state either for copper or superconducting conductors; (3) the power consumption is about 7 MW for a normal conductor; (4) the divertor can be inserted into the existing geometry of TEXTOR; (5) the ripple on axis is only 0.3% and the mirror ratio is 2 to 4; (6) the stagnation axis is concave toward the plasma, therefore q/sub D/ is smaller, the acceptance angle is larger, and the efficiency may be better than the conventional circular coil design

  12. Tuning bacterial hydrodynamics with magnetic fields

    Science.gov (United States)

    Pierce, C. J.; Mumper, E.; Brown, E. E.; Brangham, J. T.; Lower, B. H.; Lower, S. K.; Yang, F. Y.; Sooryakumar, R.

    2017-06-01

    Magnetotactic bacteria are a group of motile prokaryotes that synthesize chains of lipid-bound, magnetic nanoparticles called magnetosomes. This study exploits their innate magnetism to investigate previously unexplored facets of bacterial hydrodynamics at surfaces. Through use of weak, uniform, external magnetic fields and local, micromagnetic surface patterns, the relative strength of hydrodynamic, magnetic, and flagellar force components is tuned through magnetic control of the bacteria's orientation. The resulting swimming behaviors provide a means to experimentally determine hydrodynamic parameters and offer a high degree of control over large numbers of living microscopic entities. The implications of this controlled motion for studies of bacterial motility near surfaces and for micro- and nanotechnology are discussed.

  13. Chlamydomonas IFT25 is dispensable for flagellar assembly but required to export the BBSome from flagella

    Directory of Open Access Journals (Sweden)

    Bin Dong

    2017-11-01

    Full Text Available Intraflagellar transport (IFT particles are composed of polyprotein complexes IFT-A and IFT-B as well as cargo adaptors such as the BBSome. Two IFT-B subunits, IFT25 and IFT27 were found to form a heterodimer, which is essential in exporting the BBSome out of the cilium but not involved in flagellar assembly and cytokinesis in vertebrates. Controversial results were, however, recorded to show that defects in IFT, flagellar assembly and even cytokinesis were caused by IFT27 knockdown in Chlamydomonas reinhardtii. Using C. reinhardtii as a model organism, we report that depletion of IFT25 has no effect on flagellar assembly and does not affect the entry of the BBSome into the flagellum, but IFT25 depletion did impair BBSome movement out of the flagellum, clarifying the evolutionally conserved role of IFT25 in regulating the exit of the BBSome from the flagellum cross species. Interestingly, depletion of IFT25 causes dramatic reduction of IFT27 as expected, which does not cause defects in flagellar assembly and cytokinesis in C. reinhardtii. Our data thus support that Chlamydomonas IFT27, like its vertebrate homologues, is not involved in flagellar assembly and cytokinesis.

  14. Architecture of the flagellar apparatus and related structures in the type species of Peridinium, P. cinctum (Dinophyceae)

    DEFF Research Database (Denmark)

    Calado, A.C.; Hansen, Gert; Moestrup, Øjvind

    1999-01-01

    The ultrastructure of Peridinium cinctum, was examined by serial sectioning with particular emphasis on the detailed construction of the flagellar apparatus. The pusular system of P. cinctum included two sac pusules in open connection with the flagellar canals; disorganized material was found ins...

  15. Evaluating big deal journal bundles.

    Science.gov (United States)

    Bergstrom, Theodore C; Courant, Paul N; McAfee, R Preston; Williams, Michael A

    2014-07-01

    Large commercial publishers sell bundled online subscriptions to their entire list of academic journals at prices significantly lower than the sum of their á la carte prices. Bundle prices differ drastically between institutions, but they are not publicly posted. The data that we have collected enable us to compare the bundle prices charged by commercial publishers with those of nonprofit societies and to examine the types of price discrimination practiced by commercial and nonprofit journal publishers. This information is of interest to economists who study monopolist pricing, librarians interested in making efficient use of library budgets, and scholars who are interested in the availability of the work that they publish.

  16. Role of calmodulin and calcineurin in regulating flagellar motility and wave polarity in Leishmania.

    Science.gov (United States)

    Mukhopadhyay, Aakash Gautam; Dey, Chinmoy Sankar

    2017-11-01

    We have previously reported the involvement of cyclic AMP in regulating flagellar waveforms in Leishmania. Here, we investigated the roles of calcium, calmodulin, and calcineurin in flagellar motility regulation in L. donovani. Using high-speed videomicroscopy, we show that calcium-independent calmodulin and calcineurin activity is necessary for motility in Leishmania. Inhibition of calmodulin and calcineurin induced ciliary beats interrupting flagellar beating in both live (in vivo) and ATP-reactivated (in vitro) parasites. Our results indicate that signaling mediated by calmodulin and calcineurin operates antagonistically to cAMP signaling in regulating the waveforms of Leishmania flagellum. These two pathways are possibly involved in maintaining the balance between the two waveforms, essential for responding to environmental cues, survival, and infectivity.

  17. Flagellar coordination in Chlamydomonas cells held on micropipettes.

    Science.gov (United States)

    Rüffer, U; Nultsch, W

    1998-01-01

    The two flagella of Chlamydomonas are known to beat synchronously: During breaststroke beating they are generally coordinated in a bilateral way while in shock responses during undulatory beating coordination is mostly parallel [Rüffer and Nultsch, 1995: Botanica Acta 108:169-276]. Analysis of a great number of shock responses revealed that in undulatory beats also periods of bilateral coordination are found and that the coordination type may change several times during a shock response, without concomitant changes of the beat envelope and the beat period. In normal wt cells no coordination changes are found during breaststroke beating, but only short temporary asynchronies: During 2 or 3 normal beats of the cis flagellum, the trans flagellum performs 3 or 4 flat beats with a reduced beat envelope and a smaller beat period, resulting in one additional trans beat. Long periods with flat beats of the same shape and beat period are found in both flagella of the non-phototactic mutant ptx1 and in defective wt 622E cells. During these periods, the coordination is parallel, the two flagella beat alternately. A correlation between normal asynchronous trans beats and the parallel-coordinated beats in the presumably cis defective cells and also the undulatory beats is discussed. In the cis defective cells, a perpetual spontaneous change between parallel beats with small beat periods (higher beat frequency) and bilateral beats with greater beat periods (lower beat frequency) are observed and render questionable the existence of two different intrinsic beat frequencies of the two flagella cis and trans. Asynchronies occur spontaneously but may also be induced by light changes, either step-up or step-down, but not by both stimuli in turn as breaststroke flagellar photoresponses (BFPRs). Asynchronies are not involved in phototaxis. They are independent of the BFPRs, which are supposed to be the basis of phototaxis. Both types of coordination must be assumed to be regulated

  18. Left bundle-branch block

    DEFF Research Database (Denmark)

    Risum, Niels; Strauss, David; Sogaard, Peter

    2013-01-01

    The relationship between myocardial electrical activation by electrocardiogram (ECG) and mechanical contraction by echocardiography in left bundle-branch block (LBBB) has never been clearly demonstrated. New strict criteria for LBBB based on a fundamental understanding of physiology have recently...

  19. MAVEN EUV Modelled Data Bundle

    Data.gov (United States)

    National Aeronautics and Space Administration — This bundle contains solar irradiance spectra in 1-nm bins from 0-190 nm. The spectra are generated based upon the Flare Irradiance Spectra Model - Mars (FISM-M)...

  20. MAVEN SEP Calibrated Data Bundle

    Data.gov (United States)

    National Aeronautics and Space Administration — The maven.sep.calibrated Level 2 Science Data Bundle contains fully calibrated SEP data, as well as the raw count data from which they are derived, and ancillary...

  1. Bundling ecosystem services in Denmark

    DEFF Research Database (Denmark)

    Turner, Katrine Grace; Odgaard, Mette Vestergaard; Bøcher, Peder Klith

    2014-01-01

    We made a spatial analysis of 11 ecosystem services at a 10 km × 10 km grid scale covering most of Denmark. Our objective was to describe their spatial distribution and interactions and also to analyze whether they formed specific bundle types on a regional scale in the Danish cultural landscape....... We found clustered distribution patterns of ecosystem services across the country. There was a significant tendency for trade-offs between on the one hand cultural and regulating services and on the other provisioning services, and we also found the potential of regulating and cultural services...... to form synergies. We identified six distinct ecosystem service bundle types, indicating multiple interactions at a landscape level. The bundle types showed specialized areas of agricultural production, high provision of cultural services at the coasts, multifunctional mixed-use bundle types around urban...

  2. Line bundles and flat connections

    Indian Academy of Sciences (India)

    1School of Mathematics, Tata Institute of Fundamental Research, Homi Bhabha Road, .... sequence for complex analytic bundles, Appendix to Topological Methods ... Society of Japan 15 (1987) (Iwanami Shoten Publishers and Princeton ...

  3. Holomorphic bundles over elliptic manifolds

    International Nuclear Information System (INIS)

    Morgan, J.W.

    2000-01-01

    In this lecture we shall examine holomorphic bundles over compact elliptically fibered manifolds. We shall examine constructions of such bundles as well as (duality) relations between such bundles and other geometric objects, namely K3-surfaces and del Pezzo surfaces. We shall be dealing throughout with holomorphic principal bundles with structure group GC where G is a compact, simple (usually simply connected) Lie group and GC is the associated complex simple algebraic group. Of course, in the special case G = SU(n) and hence GC = SLn(C), we are considering holomorphic vector bundles with trivial determinant. In the other cases of classical groups, G SO(n) or G = Sympl(2n) we are considering holomorphic vector bundles with trivial determinant equipped with a non-degenerate symmetric, or skew symmetric pairing. In addition to these classical cases there are the finite number of exceptional groups. Amazingly enough, motivated by questions in physics, much interest centres around the group E8 and its subgroups. For these applications it does not suffice to consider only the classical groups. Thus, while often first doing the case of SU(n) or more generally of the classical groups, we shall extend our discussions to the general semi-simple group. Also, we shall spend a good deal of time considering elliptically fibered manifolds of the simplest type, namely, elliptic curves

  4. The dynamic instability in the hook/flagellum system that triggers bacterial flicks

    Science.gov (United States)

    Jabbarzadeh, Mehdi; Fu, Henry

    2017-11-01

    Dynamical bending, buckling, and polymorphic transformations of the flagellum are known to affect bacterial motility, but run-reverse-flick motility of monotrichous bacteria also involves the even more flexible hook, which connects the flagellum to the cell body. Here, we identify the dynamic buckling mechanism that produces flicks in Vibrio alginolyticus. Estimates of forces and torques on the hook from experimental observations suggest that flicks are triggered at stresses below the hook's static Euler buckling criterion. Using an accurate linearization of the Kirchoff rod model for the hook in a model of a swimming bacterium with rigid flagellum, we show that as hook stiffness decreases there is a transition from on-axis flagellar rotation with small hook deflections to flagellar precession with large deflections. When flagellum flexibility is incorporated, the precession is disrupted by significant flagellar bending - i.e., incipient flicks. The predicted onset of dynamic instabilities corresponds well with experimentally observed flick events.

  5. Bacterial flagella and Type III secretion: case studies in the evolution of complexity.

    Science.gov (United States)

    Pallen, M J; Gophna, U

    2007-01-01

    Bacterial flagella at first sight appear uniquely sophisticated in structure, so much so that they have even been considered 'irreducibly complex' by the intelligent design movement. However, a more detailed analysis reveals that these remarkable pieces of molecular machinery are the product of processes that are fully compatible with Darwinian evolution. In this chapter we present evidence for such processes, based on a review of experimental studies, molecular phylogeny and microbial genomics. Several processes have played important roles in flagellar evolution: self-assembly of simple repeating subunits, gene duplication with subsequent divergence, recruitment of elements from other systems ('molecular bricolage'), and recombination. We also discuss additional tentative new assignments of homology (FliG with MgtE, FliO with YscJ). In conclusion, rather than providing evidence of intelligent design, flagellar and non-flagellar Type III secretion systems instead provide excellent case studies in the evolution of complex systems from simpler components.

  6. Crystallization and preliminary X-ray analysis of the flagellar motor `brake' molecule YcgR with c-di-GMP from Escherichia coli.

    Science.gov (United States)

    Hou, Yanjie; Li, De Feng; Wang, Da Cheng

    2013-06-01

    In Escherichia coli and Salmonella enterica, bis-(3'-5')-cyclic dimeric guanosine monophosphate (c-di-GMP), a ubiquitous bacterial second-messenger molecule that participates in many cellular processes, can regulate flagellar motor speed and reduce cell swimming velocity by binding to the PilZ-containing protein YcgR. Here, the crystallization and preliminary X-ray crystallographic analysis of YcgR with c-di-GMP are reported. The crystals diffracted to 2.3 Å resolution and belonged to space group R3:H, with unit-cell parameters a = b = 93.96, c = 109.61 Å. The asymmetric unit appeared to contain one subunit with a Matthews coefficient of 3.21 Å(3) Da(-1). The results reported here provide a sound basis for solving the crystal structure of YcgR with c-di-GMP and revealing its structure-function relationship based on the three-dimensional structure.

  7. Minimum Information Loss Based Multi-kernel Learning for Flagellar Protein Recognition in Trypanosoma Brucei

    KAUST Repository

    Wang, Jim Jing-Yan

    2014-12-01

    Trypanosma brucei (T. Brucei) is an important pathogen agent of African trypanosomiasis. The flagellum is an essential and multifunctional organelle of T. Brucei, thus it is very important to recognize the flagellar proteins from T. Brucei proteins for the purposes of both biological research and drug design. In this paper, we investigate computationally recognizing flagellar proteins in T. Brucei by pattern recognition methods. It is argued that an optimal decision function can be obtained as the difference of probability functions of flagella protein and the non-flagellar protein for the purpose of flagella protein recognition. We propose to learn a multi-kernel classification function to approximate this optimal decision function, by minimizing the information loss of such approximation which is measured by the Kull back-Leibler (KL) divergence. An iterative multi-kernel classifier learning algorithm is developed to minimize the KL divergence for the problem of T. Brucei flagella protein recognition, experiments show its advantage over other T. Brucei flagellar protein recognition and multi-kernel learning methods. © 2014 IEEE.

  8. Self-Sustained Oscillatory Sliding Movement of Doublet Microtubules and Flagellar Bend Formation.

    Directory of Open Access Journals (Sweden)

    Sumio Ishijima

    Full Text Available It is well established that the basis for flagellar and ciliary movements is ATP-dependent sliding between adjacent doublet microtubules. However, the mechanism for converting microtubule sliding into flagellar and ciliary movements has long remained unresolved. The author has developed new sperm models that use bull spermatozoa divested of their plasma membrane and midpiece mitochondrial sheath by Triton X-100 and dithiothreitol. These models enable the observation of both the oscillatory sliding movement of activated doublet microtubules and flagellar bend formation in the presence of ATP. A long fiber of doublet microtubules extruded by synchronous sliding of the sperm flagella and a short fiber of doublet microtubules extruded by metachronal sliding exhibited spontaneous oscillatory movements and constructed a one beat cycle of flagellar bending by alternately actuating. The small sliding displacement generated by metachronal sliding formed helical bends, whereas the large displacement by synchronous sliding formed planar bends. Therefore, the resultant waveform is a half-funnel shape, which is similar to ciliary movements.

  9. Identification of flagellar motility genes in Yersinia ruckeri by transposon mutagenesis

    DEFF Research Database (Denmark)

    Evenhuis, Jason P:; LaPatra, Scott E.; Verner-Jeffreys, David W.

    2009-01-01

    Here we demonstrate that flagellar secretion is required for production of secreted lipase activity in the fish pathogen Yersinia ruckeri and that neither of these activities is necessary for virulence in rainbow trout. Our results suggest a possible mechanism for the emergence of nonmotile biotype...

  10. A novel flagellar sheath protein, FcpA, determines filament coiling, translational motility and virulence for the Leptospira spirochete.

    Science.gov (United States)

    Wunder, Elsio A; Figueira, Cláudio P; Benaroudj, Nadia; Hu, Bo; Tong, Brian A; Trajtenberg, Felipe; Liu, Jun; Reis, Mitermayer G; Charon, Nyles W; Buschiazzo, Alejandro; Picardeau, Mathieu; Ko, Albert I

    2016-08-01

    Leptospira are unique among bacteria based on their helical cell morphology with hook-shaped ends and the presence of periplasmic flagella (PF) with pronounced spontaneous supercoiling. The factors that provoke such supercoiling, as well as the role that PF coiling plays in generating the characteristic hook-end cell morphology and motility, have not been elucidated. We have now identified an abundant protein from the pathogen L. interrogans, exposed on the PF surface, and named it Flagellar-coiling protein A (FcpA). The gene encoding FcpA is highly conserved among Leptospira and was not found in other bacteria. fcpA(-) mutants, obtained from clinical isolates or by allelic exchange, had relatively straight, smaller-diameter PF, and were not able to produce translational motility. These mutants lost their ability to cause disease in the standard hamster model of leptospirosis. Complementation of fcpA restored the wild-type morphology, motility and virulence phenotypes. In summary, we identified a novel Leptospira 36-kDa protein, the main component of the spirochete's PF sheath, and a key determinant of the flagella's coiled structure. FcpA is essential for bacterial translational motility and to enable the spirochete to penetrate the host, traverse tissue barriers, disseminate to cause systemic infection and reach target organs. © 2016 John Wiley & Sons Ltd.

  11. GPU Parallel Bundle Block Adjustment

    Directory of Open Access Journals (Sweden)

    ZHENG Maoteng

    2017-09-01

    Full Text Available To deal with massive data in photogrammetry, we introduce the GPU parallel computing technology. The preconditioned conjugate gradient and inexact Newton method are also applied to decrease the iteration times while solving the normal equation. A brand new workflow of bundle adjustment is developed to utilize GPU parallel computing technology. Our method can avoid the storage and inversion of the big normal matrix, and compute the normal matrix in real time. The proposed method can not only largely decrease the memory requirement of normal matrix, but also largely improve the efficiency of bundle adjustment. It also achieves the same accuracy as the conventional method. Preliminary experiment results show that the bundle adjustment of a dataset with about 4500 images and 9 million image points can be done in only 1.5 minutes while achieving sub-pixel accuracy.

  12. Principal bundles the classical case

    CERN Document Server

    Sontz, Stephen Bruce

    2015-01-01

    This introductory graduate level text provides a relatively quick path to a special topic in classical differential geometry: principal bundles.  While the topic of principal bundles in differential geometry has become classic, even standard, material in the modern graduate mathematics curriculum, the unique approach taken in this text presents the material in a way that is intuitive for both students of mathematics and of physics. The goal of this book is to present important, modern geometric ideas in a form readily accessible to students and researchers in both the physics and mathematics communities, providing each with an understanding and appreciation of the language and ideas of the other.

  13. PDS4 Bundle Creation Governance Using BPMN

    Science.gov (United States)

    Radulescu, C.; Levoe, S. R.; Algermissen, S. S.; Rye, E. D.; Hardman, S. H.

    2015-06-01

    The AMMOS-PDS Pipeline Service (APPS) provides a Bundle Builder tool, which governs the process of creating, and ultimately generates, PDS4 bundles incrementally, as science products are being generated.

  14. Exploring Bundling Theory with Geometry

    Science.gov (United States)

    Eckalbar, John C.

    2006-01-01

    The author shows how instructors might successfully introduce students in principles and intermediate microeconomic theory classes to the topic of bundling (i.e., the selling of two or more goods as a package, rather than separately). It is surprising how much students can learn using only the tools of high school geometry. To be specific, one can…

  15. Episodic payments (bundling): PART I.

    Science.gov (United States)

    Jacofsky, D J

    2017-10-01

    Episodic, or bundled payments, is a concept now familiar to most in the healthcare arena, but the models are often misunderstood. Under a traditional fee-for-service model, each provider bills separately for their services which creates financial incentives to maximise volumes. Under a bundled payment, a single entity, often referred to as a convener (maybe the hospital, the physician group, or a third party) assumes the risk through a payer contract for all services provided within a defined episode of care, and receives a single (bundled) payment for all services provided for that episode. The time frame around the intervention is variable, but defined in advance, as are included and excluded costs. Timing of the actual payment in a bundle may either be before the episode occurs (prospective payment model), or after the end of the episode through a reconciliation (retrospective payment model). In either case, the defined costs over the defined time frame are borne by the convener. Cite this article: Bone Joint J 2017;99-B:1280-5. ©2017 The British Editorial Society of Bone & Joint Surgery.

  16. Deformation quantization of principal fibre bundles

    International Nuclear Information System (INIS)

    Weiss, S.

    2007-01-01

    Deformation quantization is an algebraic but still geometrical way to define noncommutative spacetimes. In order to investigate corresponding gauge theories on such spaces, the geometrical formulation in terms of principal fibre bundles yields the appropriate framework. In this talk I will explain what should be understood by a deformation quantization of principal fibre bundles and how associated vector bundles arise in this context. (author)

  17. Output commitment through product bundling : Experimental evidence

    NARCIS (Netherlands)

    Hinloopen, Jeroen; Mueller, Wieland; Normann, Hans-Theo

    We analyze the impact of product bundling in experimental markets. One firm has monopoly power in a first market but competes with another firm la Cournot in a second market. We compare treatments where the multi-product firm (i) always bundles, (ii) never bundles, and (iii) chooses whether to

  18. Induction of phospholipase- and flagellar synthesis in Serratia liquefaciens is controlled by expression of the flagellar master operon flhD

    DEFF Research Database (Denmark)

    Givskov, M; Eberl, L; Christiansen, Gunna

    1995-01-01

    . Expression of flagella is demonstrated to follow a growth-phase-dependent pattern. Cloning, complementation studies and DNA-sequencing analysis has identified a genetic region in Serratia liquefaciens which exhibits extensive homology to the Escherichia coli flhD flagellar master operon. Interruption...... of the chromosomal flhD operon in S. liquefaciens results in non-flagellated and phospholipase-negative cells, but the synthesis of other exoenzymes is not affected. By placing the flhD operon under the control of a foreign inducible promoter we have shown that increased transcription through the flhD operon leads...

  19. Induction of phospholipase- and flagellar synthesis in Serratia liquefaciens is controlled by expression of the flagellar master operon flhD

    DEFF Research Database (Denmark)

    Givskov, M; Eberl, L; Christiansen, Gunna

    1995-01-01

    When a liquid culture of Serratia spp. reaches the last part of the logarithmic phase of growth it induces the synthesis of several extracellular hydrolytic enzymes. In this communication we show that synthesis and secretion of the extracellular phospholipase is coupled to expression of flagella....... Expression of flagella is demonstrated to follow a growth-phase-dependent pattern. Cloning, complementation studies and DNA-sequencing analysis has identified a genetic region in Serratia liquefaciens which exhibits extensive homology to the Escherichia coli flhD flagellar master operon. Interruption...

  20. Higher order jet prolongations type gauge natural bundles over vector bundles

    Directory of Open Access Journals (Sweden)

    Jan Kurek

    2004-05-01

    Full Text Available Let $rgeq 3$ and $mgeq 2$ be natural numbers and $E$ be a vector bundle with $m$-dimensional basis. We find all gauge natural bundles ``similar" to the $r$-jet prolongation bundle $J^rE$ of $E$. We also find all gauge natural bundles ``similar" to the vector $r$-tangent bundle $(J^r_{fl}(E,R_0^*$ of $E$.

  1. Co-Higgs bundles on P^1

    OpenAIRE

    Rayan, Steven

    2010-01-01

    Co-Higgs bundles are Higgs bundles in the sense of Simpson, but with Higgs fields that take values in the tangent bundle instead of the cotangent bundle. Given a vector bundle on P^1, we find necessary and sufficient conditions on its Grothendieck splitting for it to admit a stable Higgs field. We characterize the rank-2, odd-degree moduli space as a universal elliptic curve with a globally-defined equation. For ranks r=2,3,4, we explicitly verify the conjectural Betti numbers emerging from t...

  2. The phylogeny of swimming kinematics: The environment controls flagellar waveforms in sperm motility

    Science.gov (United States)

    Guasto, Jeffrey; Burton, Lisa; Zimmer, Richard; Hosoi, Anette; Stocker, Roman

    2013-11-01

    In recent years, phylogenetic and molecular analyses have dominated the study of ecology and evolution. However, physical interactions between organisms and their environment, a fundamental determinant of organism ecology and evolution, are mediated by organism form and function, highlighting the need to understand the mechanics of basic survival strategies, including locomotion. Focusing on spermatozoa, we combined high-speed video microscopy and singular value decomposition analysis to quantitatively compare the flagellar waveforms of eight species, ranging from marine invertebrates to humans. We found striking similarities in sperm swimming kinematics between genetically dissimilar organisms, which could not be uncovered by phylogenetic analysis. The emergence of dominant waveform patterns across species are suggestive of biological optimization for flagellar locomotion and point toward environmental cues as drivers of this convergence. These results reinforce the power of quantitative kinematic analysis to understand the physical drivers of evolution and as an approach to uncover new solutions for engineering applications, such as micro-robotics.

  3. Flagellar filament bio-templated inorganic oxide materials – towards an efficient lithium battery anode

    Science.gov (United States)

    Beznosov, Sergei N.; Veluri, Pavan S.; Pyatibratov, Mikhail G.; Chatterjee, Abhijit; MacFarlane, Douglas R.; Fedorov, Oleg V.; Mitra, Sagar

    2015-01-01

    Designing a new generation of energy-intensive and sustainable electrode materials for batteries to power a variety of applications is an imperative task. The use of biomaterials as a nanosized structural template for these materials has the potential to produce hitherto unachievable structures. In this report, we have used genetically modified flagellar filaments of the extremely halophilic archaea species Halobacterium salinarum to synthesize nanostructured iron oxide composites for use as a lithium-ion battery anode. The electrode demonstrated a superior electrochemical performance compared to existing literature results, with good capacity retention of 1032 mAh g−1 after 50 cycles and with high rate capability, delivering 770 mAh g−1 at 5 A g−1 (~5 C) discharge rate. This unique flagellar filament based template has the potential to provide access to other highly structured advanced energy materials in the future. PMID:25583370

  4. Flagellar filament bio-templated inorganic oxide materials - towards an efficient lithium battery anode.

    Science.gov (United States)

    Beznosov, Sergei N; Veluri, Pavan S; Pyatibratov, Mikhail G; Chatterjee, Abhijit; MacFarlane, Douglas R; Fedorov, Oleg V; Mitra, Sagar

    2015-01-13

    Designing a new generation of energy-intensive and sustainable electrode materials for batteries to power a variety of applications is an imperative task. The use of biomaterials as a nanosized structural template for these materials has the potential to produce hitherto unachievable structures. In this report, we have used genetically modified flagellar filaments of the extremely halophilic archaea species Halobacterium salinarum to synthesize nanostructured iron oxide composites for use as a lithium-ion battery anode. The electrode demonstrated a superior electrochemical performance compared to existing literature results, with good capacity retention of 1032 mAh g(-1) after 50 cycles and with high rate capability, delivering 770 mAh g(-1) at 5 A g(-1) (~5 C) discharge rate. This unique flagellar filament based template has the potential to provide access to other highly structured advanced energy materials in the future.

  5. Flagellar apparatus and nuclear chambers of the green dinoflagellate Gymnodinium chlorophorum

    DEFF Research Database (Denmark)

    Hansen, Gert; Moestrup, Øjvind

    2005-01-01

    The green dinoflagellate Gymnodinium chlorophorum (BAH ME 100, the type culture) was reexamined with emphasis on the structure of the flagellar apparatus and nuclear envelope. Like other Gymnodinium species, G. chlorophorum possessed a nuclear fibrous connective linking the flagellar apparatus...... present in G. chlorophorum similar to those reported in Gymnodinium aureolum and Gymnodinium nolleri. In contrast to the type species of Gymnodinium, Gymnodinium fuscum, only one nuclear pore was present per chamber. The presence of a feeding tube (peduncle) suggests that G. chlorophorum is mixotrophic....... Although the fine structure of G. chlorophorum revealed its affiliation to the Gymnodinium group the above discrepancies set it apart, indicating that it might belong in a different genus....

  6. Molecular automata assembly: principles and simulation of bacterial membrane construction.

    Science.gov (United States)

    Lahoz-Beltra, R

    1997-01-01

    The motivation to understand the basic rules and principles governing molecular self-assembly may be relevant to explain in the context of molecular biology the self-organization and biological functions exhibited within cells. This paper presents a molecular automata model to simulate molecular self-assembly introducing the concept of molecular programming to simulate the biological function or operation performed by an assembled molecular state machine. The method is illustrated modelling Escherichia coli membrane construction including the assembly and operation of ATP synthase as well as the assembly of the bacterial flagellar motor. Flagellar motor operation was simulated using a different approach based on state machine definition used in virtual reality systems. The proposed methodology provides a modelling framework for simulation of biological functions performed by cellular components and other biological systems suitable to be modelled as molecular state machines.

  7. Emergence of flagellar beating from the collective behavior of individual ATP-powered dyneins

    OpenAIRE

    Namdeo, S.; Onck, P. R.

    2016-01-01

    Flagella are hair-like projections from the surface of eukaryotic cells, and they play an important role in many cellular functions, such as cell-motility. The beating of flagella is enabled by their internal architecture, the axoneme, and is powered by a dense distribution of motor proteins, dyneins. The dyneins deliver the required mechanical work through the hydrolysis of ATP. Although the dynein-ATP cycle, the axoneme microstructure, and the flagellar-beating kinematics are well studied, ...

  8. Boiling heat transfer on horizontal tube bundles

    International Nuclear Information System (INIS)

    Anon.

    1987-01-01

    Nucleate boiling heat transfer characteristics for a tube in a bundle differ from that for a single tube in a pool and this difference is known as 'tube bundle effect.' There exist two bundle effects, positive and negative. The positive bundle effect enhances heat transfer due to convective flow induced by rising bubbles generated from the lower tubes, while the negative bundle effect deteriorates heat transfer due to vapor blanketing caused by accumulation of bubbles. Staggered tube bundles tested and found that the upper tubes in bundles have higher heat transfer coefficients than the lower tubes. The effects of various parameters such as pressure, tube geometry and oil contamination on heat transfer have been examined. Some workers attempted to clarify the mechanism of occurrence of 'bundle effect' by testing tube arrangements of small scale. All reported only enhancement in heat transfer but results showed the symptom of heat transfer deterioration at higher heat fluxes. As mentioned above, it has not been clarified so far even whether the 'tube bundle effect' should serve as enhancement or deterioration of heat transfer in nucleate boiling. In this study, experiments are performed in detail by using bundles of small scale, and effects of heat flux distribution, pressure and tube location are clarified. Furthermore, some consideration on the mechanisms of occurrence of 'tube bundle effect' is made and a method for prediction of heat transfer rate is proposed

  9. Fluid structure interaction in tube bundles

    International Nuclear Information System (INIS)

    Brochard, D.; Jedrzejewski, F.; Gibert, R.J.

    1995-01-01

    A lot of industrial components contain tube bundles immersed in a fluid. The mechanical analysis of such systems requires the study of the fluid structure interaction in the tube bundle. Simplified methods, based on homogenization methods, have been developed to analyse such phenomenon and have been validated through experimental results. Generally, these methods consider only the fluid motion in a plan normal to the bundle axis. This paper will analyse, in a first part, the fluid structure interaction in a tube bundle through a 2D finite element model representing the bundle cross section. The influence of various parameters like the bundle size, and the bundle confinement will be studied. These results will be then compared with results from homogenization methods. Finally, the influence of the 3D fluid motion will be investigated, in using simplified methods. (authors). 11 refs., 12 figs., 2 tabs

  10. Development of CANFLEX fuel bundle

    International Nuclear Information System (INIS)

    Suk, Ho Chun; Hwang, Woan; Jeong, Young Hwan

    1991-12-01

    This research project is underway in cooperation with AECL to develop the CANDU advanced fuel bundle(so-called CANFLEX) which can enhance reactor safety and fuel economy in comparison with the current CANDU fuel and which can be used with natural uranium, slightly enriched uranium and other advanced fuel cycle. As the final schedule, the advanced fuel will be verified by carrying out a large scale demonstration of the bundle irradiation in a commercial CANDU reactors for 1996 and 1997, and consequently will be used in the existing and future reactors in Korea. The research activities during this year include the basic design of CANFLEX fuel with slightly enriched uranium(CANFLEX-SEU), with emphasis on the extension of fuel operation limit. Based on this basic design, CANFLEX fuel was mocked up. Out-of-pile hydraulic scoping tests were conducted with the fuel. (Author)

  11. Emergence of flagellar beating from the collective behavior of individual ATP-powered dyneins

    Science.gov (United States)

    Namdeo, S.; Onck, P. R.

    2016-10-01

    Flagella are hair-like projections from the surface of eukaryotic cells, and they play an important role in many cellular functions, such as cell-motility. The beating of flagella is enabled by their internal architecture, the axoneme, and is powered by a dense distribution of motor proteins, dyneins. The dyneins deliver the required mechanical work through the hydrolysis of ATP. Although the dynein-ATP cycle, the axoneme microstructure, and the flagellar-beating kinematics are well studied, their integration into a coherent picture of ATP-powered flagellar beating is still lacking. Here we show that a time-delayed negative-work-based switching mechanism is able to convert the individual sliding action of hundreds of dyneins into a regular overall beating pattern leading to propulsion. We developed a computational model based on a minimal representation of the axoneme consisting of two representative doublet microtubules connected by nexin links. The relative sliding of the microtubules is incorporated by modeling two groups of ATP-powered dyneins, each responsible for sliding in opposite directions. A time-delayed switching mechanism is postulated, which is key in converting the local individual sliding action of multiple dyneins into global beating. Our results demonstrate that an overall nonreciprocal beating pattern can emerge with time due to the spatial and temporal coordination of the individual dyneins. These findings provide insights in the fundamental working mechanism of axonemal dyneins and could possibly open new research directions in the field of flagellar motility.

  12. Trypanin, a component of the flagellar Dynein regulatory complex, is essential in bloodstream form African trypanosomes.

    Directory of Open Access Journals (Sweden)

    Katherine S Ralston

    2006-09-01

    Full Text Available The Trypanosoma brucei flagellum is a multifunctional organelle with critical roles in motility, cellular morphogenesis, and cell division. Although motility is thought to be important throughout the trypanosome lifecycle, most studies of flagellum structure and function have been restricted to the procyclic lifecycle stage, and our knowledge of the bloodstream form flagellum is limited. We have previously shown that trypanin functions as part of a flagellar dynein regulatory system that transmits regulatory signals from the central pair apparatus and radial spokes to axonemal dyneins. Here we investigate the requirement for this dynein regulatory system in bloodstream form trypanosomes. We demonstrate that trypanin is localized to the flagellum of bloodstream form trypanosomes, in a pattern identical to that seen in procyclic cells. Surprisingly, trypanin RNA interference is lethal in the bloodstream form. These knockdown mutants fail to initiate cytokinesis, but undergo multiple rounds of organelle replication, accumulating multiple flagella, nuclei, kinetoplasts, mitochondria, and flagellum attachment zone structures. These findings suggest that normal flagellar beat is essential in bloodstream form trypanosomes and underscore the emerging concept that there is a dichotomy between trypanosome lifecycle stages with respect to factors that contribute to cell division and cell morphogenesis. This is the first time that a defined dynein regulatory complex has been shown to be essential in any organism and implicates the dynein regulatory complex and other enzymatic regulators of flagellar motility as candidate drug targets for the treatment of African sleeping sickness.

  13. Competitive nonlinear pricing and bundling

    OpenAIRE

    Armstrong, Mark; Vickers, John

    2006-01-01

    We examine the impact of multiproduct nonlinear pricing on profit, consumer surplus and welfare in a duopoly. When consumers buy all their products from one firm (the one-stop shopping model), nonlinear pricing leads to higher profit and welfare, but often lower consumer surplus, than linear pricing. By contrast, in a unit-demand model where consumers may buy one product from one firm and another product from another firm, bundling generally acts to reduce profit and welfare and to boost cons...

  14. Signal detection by active, noisy hair bundles

    Science.gov (United States)

    O'Maoiléidigh, Dáibhid; Salvi, Joshua D.; Hudspeth, A. J.

    2018-05-01

    Vertebrate ears employ hair bundles to transduce mechanical movements into electrical signals, but their performance is limited by noise. Hair bundles are substantially more sensitive to periodic stimulation when they are mechanically active, however, than when they are passive. We developed a model of active hair-bundle mechanics that predicts the conditions under which a bundle is most sensitive to periodic stimulation. The model relies only on the existence of mechanotransduction channels and an active adaptation mechanism that recloses the channels. For a frequency-detuned stimulus, a noisy hair bundle's phase-locked response and degree of entrainment as well as its detection bandwidth are maximized when the bundle exhibits low-amplitude spontaneous oscillations. The phase-locked response and entrainment of a bundle are predicted to peak as functions of the noise level. We confirmed several of these predictions experimentally by periodically forcing hair bundles held near the onset of self-oscillation. A hair bundle's active process amplifies the stimulus preferentially over the noise, allowing the bundle to detect periodic forces less than 1 pN in amplitude. Moreover, the addition of noise can improve a bundle's ability to detect the stimulus. Although, mechanical activity has not yet been observed in mammalian hair bundles, a related model predicts that active but quiescent bundles can oscillate spontaneously when they are loaded by a sufficiently massive object such as the tectorial membrane. Overall, this work indicates that auditory systems rely on active elements, composed of hair cells and their mechanical environment, that operate on the brink of self-oscillation.

  15. Intraflagellar transport particle size scales inversely with flagellar length: revisiting the balance-point length control model.

    Science.gov (United States)

    Engel, Benjamin D; Ludington, William B; Marshall, Wallace F

    2009-10-05

    The assembly and maintenance of eukaryotic flagella are regulated by intraflagellar transport (IFT), the bidirectional traffic of IFT particles (recently renamed IFT trains) within the flagellum. We previously proposed the balance-point length control model, which predicted that the frequency of train transport should decrease as a function of flagellar length, thus modulating the length-dependent flagellar assembly rate. However, this model was challenged by the differential interference contrast microscopy observation that IFT frequency is length independent. Using total internal reflection fluorescence microscopy to quantify protein traffic during the regeneration of Chlamydomonas reinhardtii flagella, we determined that anterograde IFT trains in short flagella are composed of more kinesin-associated protein and IFT27 proteins than trains in long flagella. This length-dependent remodeling of train size is consistent with the kinetics of flagellar regeneration and supports a revised balance-point model of flagellar length control in which the size of anterograde IFT trains tunes the rate of flagellar assembly.

  16. Job Management and Task Bundling

    Science.gov (United States)

    Berkowitz, Evan; Jansen, Gustav R.; McElvain, Kenneth; Walker-Loud, André

    2018-03-01

    High Performance Computing is often performed on scarce and shared computing resources. To ensure computers are used to their full capacity, administrators often incentivize large workloads that are not possible on smaller systems. Measurements in Lattice QCD frequently do not scale to machine-size workloads. By bundling tasks together we can create large jobs suitable for gigantic partitions. We discuss METAQ and mpi_jm, software developed to dynamically group computational tasks together, that can intelligently backfill to consume idle time without substantial changes to users' current workflows or executables.

  17. Job Management and Task Bundling

    Directory of Open Access Journals (Sweden)

    Berkowitz Evan

    2018-01-01

    Full Text Available High Performance Computing is often performed on scarce and shared computing resources. To ensure computers are used to their full capacity, administrators often incentivize large workloads that are not possible on smaller systems. Measurements in Lattice QCD frequently do not scale to machine-size workloads. By bundling tasks together we can create large jobs suitable for gigantic partitions. We discuss METAQ and mpi_jm, software developed to dynamically group computational tasks together, that can intelligently backfill to consume idle time without substantial changes to users’ current workflows or executables.

  18. Fuel bundle for nuclear reactor

    International Nuclear Information System (INIS)

    Long, J.W.; Flora, B.S.; Ford, K.L.

    1977-01-01

    The invention concerns a new, simple and inexpensive system for assembling and dismantling a nuclear reactor fuel bundle. Several fuel rods are fitted in parallel rows between two retaining plates which secure the fuel rods in position and which are maintained in an assembled position by means of several stays fixed to the two end plates. The invention particularly refers to an improved apparatus for fixing the stays to the upper plate by using locking fittings secured to rotating sleeves which are applied against this plate [fr

  19. Reduction of symplectic principal R-bundles

    International Nuclear Information System (INIS)

    Lacirasella, Ignazio; Marrero, Juan Carlos; Padrón, Edith

    2012-01-01

    We describe a reduction process for symplectic principal R-bundles in the presence of a momentum map. These types of structures play an important role in the geometric formulation of non-autonomous Hamiltonian systems. We apply this procedure to the standard symplectic principal R-bundle associated with a fibration π:M→R. Moreover, we show a reduction process for non-autonomous Hamiltonian systems on symplectic principal R-bundles. We apply these reduction processes to several examples. (paper)

  20. ACM Bundles on Del Pezzo surfaces

    Directory of Open Access Journals (Sweden)

    Joan Pons-Llopis

    2009-11-01

    Full Text Available ACM rank 1 bundles on del Pezzo surfaces are classified in terms of the rational normal curves that they contain. A complete list of ACM line bundles is provided. Moreover, for any del Pezzo surface X of degree less or equal than six and for any n ≥ 2 we construct a family of dimension ≥ n − 1 of non-isomorphic simple ACM bundles of rank n on X.

  1. Bundling and mergers in energy markets

    International Nuclear Information System (INIS)

    Granier, Laurent; Podesta, Marion

    2010-01-01

    Does bundling trigger mergers in energy industries? We observe mergers between firms belonging to various energy markets, for instance between gas and electricity providers. These mergers enable firms to bundle. We consider two horizontally differentiated markets. In this framework, we show that bundling strategies in energy markets create incentives to form multi-market firms in order to supply bi-energy packages. Moreover, we find that this type of merger is detrimental to social welfare. (author)

  2. Entropy for frame bundle systems and Grassmann bundle systems induced by a diffeomorphism

    Institute of Scientific and Technical Information of China (English)

    SUN; Weniang(孙文祥)

    2002-01-01

    ALiao hyperbolic diffeomorphism has equal measure entropy and topological entropy to that ofits induced systems on frame bundles and Grassmann bundles. This solves a problem Liao posed in 1996 forLiao hyperbolic diffeomorphisms.

  3. Hydraulic characteristics of HANARO fuel bundles

    Energy Technology Data Exchange (ETDEWEB)

    Cho, S.; Chung, H. J.; Chun, S. Y.; Yang, S. K.; Chung, M. K. [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1997-12-31

    This paper presents the hydraulic characteristics measured by using LDV (Laser Doppler Velocimetry) in subchannels of HANARO, KAERI research reactor, fuel bundle. The fuel bundle consists of 18 axially finned rods with 3 spacer grids, which are arranged in cylindrical configuration. The effects of the spacer grids on the turbulent flow were investigated by the experimental results. Pressure drops for each component of the fuel bundle were measured, and the friction factors of fuel bundle and loss coefficients for the spacer grids were estimated from the measured pressure drops. Implications regarding the turbulent thermal mixing were discussed. Vibration test results measured by using laser vibrometer were presented. 9 refs., 12 figs. (Author)

  4. Hydraulic characteristics of HANARO fuel bundles

    Energy Technology Data Exchange (ETDEWEB)

    Cho, S; Chung, H J; Chun, S Y; Yang, S K; Chung, M K [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1998-12-31

    This paper presents the hydraulic characteristics measured by using LDV (Laser Doppler Velocimetry) in subchannels of HANARO, KAERI research reactor, fuel bundle. The fuel bundle consists of 18 axially finned rods with 3 spacer grids, which are arranged in cylindrical configuration. The effects of the spacer grids on the turbulent flow were investigated by the experimental results. Pressure drops for each component of the fuel bundle were measured, and the friction factors of fuel bundle and loss coefficients for the spacer grids were estimated from the measured pressure drops. Implications regarding the turbulent thermal mixing were discussed. Vibration test results measured by using laser vibrometer were presented. 9 refs., 12 figs. (Author)

  5. Cotangent bundle approach to noninertial frames

    International Nuclear Information System (INIS)

    DeFacio, B.; Retzloff, D.

    1980-01-01

    The most general possible noninertial acceleration in special relativity is formulated with differential forms in the cotangent bundle. We show that the Lie derivative plays the same role in the cotangent bundle that the covariant derivative plays in the tangent bundle. We also show that a cotangent bundle analog of Fermi--Walker transport can be based upon the, ''cotangent-geodesic'' equation, L/sub u/ω=0. This gives a generalization of the work by Kiehn on classical Hamiltonian mechanics to special relativity

  6. Polymorphism in Bacterial Flagella Suspensions

    Science.gov (United States)

    Schwenger, Walter J.

    Bacterial flagella are a type of biological polymer studied for its role in bacterial motility and the polymorphic transitions undertaken to facilitate the run and tumble behavior. The naturally rigid, helical shape of flagella gives rise to novel colloidal dynamics and material properties. This thesis studies methods in which the shape of bacterial flagella can be controlled using in vitro methods and the changes the shape of the flagella have on both single particle dynamics and bulk material properties. We observe individual flagellum in both the dilute and semidilute regimes to observe the effects of solvent condition on the shape of the filament as well as the effect the filament morphology has on reptation through a network of flagella. In addition, we present rheological measurements showing how the shape of filaments effects the bulk material properties of flagellar suspensions. We find that the individual particle dynamics in suspensions of flagella can vary with geometry from needing to reptate linearly via rotation for helical filaments to the prevention of long range diffusion for block copolymer filaments. Similarly, for bulk material properties of flagella suspensions, helical geometries show a dramatic enhancement in elasticity over straight filaments while block copolymers form an elastic gel without the aid of crosslinking agents.

  7. CANFLEX fuel bundle junction pressure drop

    International Nuclear Information System (INIS)

    Chung, H. J.; Chung, C. H.; Jun, J. S.; Hong, S. D.; Chang, S. K.; Kim, B. D.

    1996-11-01

    This report describes the junction pressure drop test results which are to used to determine the alignment angle between bundles to achieve the most probable fuel string pressure drop for randomly aligned bundles for use in the fuel string total pressure drop test. (author). 4 tabs., 17 figs

  8. Anatomic Double-bundle ACL Reconstruction

    NARCIS (Netherlands)

    Schreiber, Verena M.; van Eck, Carola F.; Fu, Freddie H.

    2010-01-01

    Rupture of the anterior cruciate ligament (ACL) is one of the most frequent forms of knee trauma. The traditional surgical treatment for ACL rupture is single-bundle reconstruction. However, during the past few years there has been a shift in interest toward double-bundle reconstruction to closely

  9. CANFLEX fuel bundle strength tests (test report)

    International Nuclear Information System (INIS)

    Chang, Seok Kyu; Chung, C. H.; Kim, B. D.

    1997-08-01

    This document outlines the test results for the strength tests of the CANFLEX fuel bundle. Strength tests are performed to determine and verify the amount of the bundle shape distortion which is against the side-stops when the bundles are refuelling. There are two cases of strength test; one is the double side-stop test which simulates the normal bundle refuelling and the other is the single side-stop test which simulates the abnormal refuelling. the strength test specification requires that the fuel bundle against the side-stop(s) simulators for this test were fabricated and the flow rates were controlled to provide the required conservative hydraulic forces. The test rig conditions of 120 deg C, 11.2 MPa were retained for 15 minutes after the flow rate was controlled during the test in two cases, respectively. The bundle loading angles of number 13- number 15 among the 15 bundles were 67.5 deg CCW and others were loaded randomly. After the tests, the bundle shapes against the side-stops were measured and inspected carefully. The important test procedures and measurements were discussed as follows. (author). 5 refs., 22 tabs., 5 figs

  10. CANFLEX fuel bundle junction pressure drop

    Energy Technology Data Exchange (ETDEWEB)

    Chung, H. J.; Chung, C. H.; Jun, J. S.; Hong, S. D.; Chang, S. K.; Kim, B. D.

    1996-11-01

    This report describes the junction pressure drop test results which are to used to determine the alignment angle between bundles to achieve the most probable fuel string pressure drop for randomly aligned bundles for use in the fuel string total pressure drop test. (author). 4 tabs., 17 figs.

  11. Output commitment through product bundling: experimental evidence

    NARCIS (Netherlands)

    Hinloopen, J.; Mueller, W.; Normann, H.T.

    2011-01-01

    We analyze the impact of product bundling in experimental markets. A firm has monopoly power in one market but faces competition by a second firm in another market. We compare treatments where the monopolist can bundle its two products to treatments where it cannot, and we contrast simultaneous and

  12. Fuel bundle movement due to reverse flow

    Energy Technology Data Exchange (ETDEWEB)

    Wahba, N N; Akalin, O [Ontario Hydro, Toronto, ON (Canada)

    1996-12-31

    When a break occurs in the inlet feeder or inlet header, the rapid depressurization will cause the channel flow to reverse forcing the string of bundles to accelerate and impact with upstream shield plug. A model has been developed to predict the bundle motion due to the channel flow reversal. The model accounts for various forces acting on the bundle. A series of five reverse flow, bundle acceleration experiments have been conducted simulating a break in the inlet feeder of a CANDU fuel channel. The model has been validated against the experiments. The predicted impact velocities are in good agreement with the measured values. It is demonstrated that the model may be successfully used in predicting bundle relocation timing following a large LOCA (loss of coolant). (author). 7 refs., 3 tabs., 11 figs.

  13. Chiral equations and fiber bundles

    International Nuclear Information System (INIS)

    Mateos, T.; Becerril, R.

    1992-01-01

    Using the hypothesis g = g (lambda i ), the chiral equations (rhog, z g -1 ), z -bar + (rhog, z -barg -1 ), z = 0 are reduced to a Killing equation of a p-dimensional space V p , being lambda i lambda i (z, z-bar) 'geodesic' parameters of V p . Supposing that g belongs to a Lie group G, one writes the corresponding Lie algebra elements (F) in terms of the Killing vectors of V p and the generators of the subalgebra of F of dimension d = dimension of the Killing space. The elements of the subalgebras belong to equivalence classes which in the respective group form a principal fiber bundle. This is used to integrate the matrix g in terms of the complex variables z and z-bar ( Author)

  14. Constructing co-Higgs bundles on CP^2

    OpenAIRE

    Rayan, Steven

    2013-01-01

    On a complex manifold, a co-Higgs bundle is a holomorphic vector bundle with an endomorphism twisted by the tangent bundle. The notion of generalized holomorphic bundle in Hitchin's generalized geometry coincides with that of co-Higgs bundle when the generalized complex manifold is ordinary complex. Schwarzenberger's rank-2 vector bundle on the projective plane, constructed from a line bundle on the double cover CP^1 \\times CP^1 \\to CP^2, is naturally a co-Higgs bundle, with the twisted endom...

  15. Nonlinear instability in flagellar dynamics: a novel modulation mechanism in sperm migration?

    KAUST Repository

    Gadelha, H.

    2010-05-12

    Throughout biology, cells and organisms use flagella and cilia to propel fluid and achieve motility. The beating of these organelles, and the corresponding ability to sense, respond to and modulate this beat is central to many processes in health and disease. While the mechanics of flagellum-fluid interaction has been the subject of extensive mathematical studies, these models have been restricted to being geometrically linear or weakly nonlinear, despite the high curvatures observed physiologically. We study the effect of geometrical nonlinearity, focusing on the spermatozoon flagellum. For a wide range of physiologically relevant parameters, the nonlinear model predicts that flagellar compression by the internal forces initiates an effective buckling behaviour, leading to a symmetry-breaking bifurcation that causes profound and complicated changes in the waveform and swimming trajectory, as well as the breakdown of the linear theory. The emergent waveform also induces curved swimming in an otherwise symmetric system, with the swimming trajectory being sensitive to head shape-no signalling or asymmetric forces are required. We conclude that nonlinear models are essential in understanding the flagellar waveform in migratory human sperm; these models will also be invaluable in understanding motile flagella and cilia in other systems.

  16. Evaluation of droplet deposition in rod bundle

    International Nuclear Information System (INIS)

    Ji, W.; Gu, C.Y.; Anglart, H.

    1997-01-01

    Deposition model for droplets in gas droplet two-phase flow in rod bundle is developed in this work using the Lagrangian method. The model is evaluated in a 9-rod bundle geometry. The deposition coefficient in the bundle geometry are compared with that in round tube. The influences of the droplet size and gas mass flow rate on deposition coefficient are investigated. Furthermore, the droplet motion is studied in more detail by dividing the bundle channel into sub-channels. The results show that the overall deposition coefficient in the bundle geometry is close to that in the round tube with the diameter equal to the bundle hydraulic diameter. The calculated deposition coefficient is found to be higher for higher gas mass flux and smaller droplets. The study in the sub-channels show that the ratio between the local deposition coefficient for a sub-channel and the averaged value for the whole bundle is close to a constant value, deviations from the mean value for all the calculated cases being within the range of ±13%. (author)

  17. Preliminary report: NIF laser bundle review

    International Nuclear Information System (INIS)

    Tietbohl, G.L.; Larson, D.W.; Erlandson, A.C.

    1995-01-01

    As requested in the guidance memo 1 , this committe determined whether there are compelling reasons to recommend a change from the NIF CDR baseline laser. The baseline bundle design based on a tradeoff between cost and technical risk, which is replicated four times to create the required 192 beams. The baseline amplifier design uses bottom loading 1x4 slab and flashlamp cassettes for amplifier maintenance and large vacuum enclosures (2.5m high x 7m wide in cross-section for each of the two spatial filters in each of the four bundles. The laser beams are arranged in two laser bays configured in a u-shape around the target area. The entire bundle review effort was performed in a very short time (six weeks) and with limited resources (15 personnel part-time). This should be compared to the effort that produced the CDR design (12 months, 50 to 100 personnel). This committee considered three alternate bundle configurations (2x2, 4x2, and 4x4 bundles), and evaluated each bundle against the baseline design using the seven requested issues in the guidance memo: Cost; schedule; performance risk; maintainability/operability; hardware failure cost exposure; activation; and design flexibility. The issues were reviewed to identify differences between each alternate bundle configuration and the baseline

  18. Ultrastructure of the harmful unarmored dinoflagellate Cochlodinium polykrikoides (Dinophyceae) with reference to the apical groove and Flagellar apparatus.

    Science.gov (United States)

    Iwataki, Mitsunori; Hansen, Gert; Moestrup, Øjvind; Matsuoka, Kazumi

    2010-01-01

    The external and internal ultrastructure of the harmful unarmored dinoflagellate Cochlodinium polykrikoides Margalef has been examined with special reference to the apical groove and three-dimensional structure of the flagellar apparatus. The apical groove is U-shaped and connected to the anterior sulcal extension on the dorsal side of the epicone. The eyespot is located dorsally and composed of two layers of globules situated within the chloroplast. A narrow invagination of the plasma membrane is associated with the eyespot. The nuclear envelope has normal nuclear pores similar to other eukaryotes but different from the Gymnodinium group with diagnostic nuclear chambers. The longitudinal and transverse basal bodies are separated by approximately 0.5-1.0 microm and interconnected directly by a striated basal body connective and indirectly by microtubular and fibrous structures. Characteristic features of the flagellar apparatus are as follows: (1) a nuclear extension projects to the R1 (longitudinal microtubular root) and is connected to the root by thin fibrous material; (2) fibrillar structures are associated with the longitudinal and transverse flagellar canal; and (3) a striated ventral connective extends toward the posterior end of the cell along the longitudinal flagellar canal. We conclude, based on both morphological and molecular evidence, that Cochlodinium is only distantly related to Gymnodinium.

  19. Bundle duct interaction studies for fuel assemblies

    International Nuclear Information System (INIS)

    Hsia, H.T.S.; Kaplan, S.

    1981-06-01

    It is known that the wire-wrapped rods and duct in an LMFBR are undergoing a gradual structural distortion from the initially uniform geometry under the combined effects of thermal expansion and irradiation induced swelling and creep. These deformations have a significant effect on flow characteristics, thus causing changes in thermal behavior such as cladding temperature and temperature distribution within a bundle. The temperature distribution may further enhance or retard irradiation induced deformation of the bundle. This report summarizes the results of the continuing effort in investigating the bundle-duct interaction, focusing on the need for the large development plant

  20. Geometry of Quantum Principal Bundles. Pt. 1

    International Nuclear Information System (INIS)

    Durdevic, M.

    1996-01-01

    A theory of principal bundles possessing quantum structure groups and classical base manifolds is presented. Structural analysis of such quantum principal bundles is performed. A differential calculus is constructed, combining differential forms on the base manifold with an appropriate differential calculus on the structure quantum group. Relations between the calculus on the group and the calculus on the bundle are investigated. A concept of (pseudo)tensoriality is formulated. The formalism of connections is developed. In particular, operators of horizontal projection, covariant derivative and curvature are constructed and analyzed. Generalizations of the first Structure Equation and of the Bianchi identity are found. Illustrative examples are presented. (orig.)

  1. Bundles of C*-categories and duality

    OpenAIRE

    Vasselli, Ezio

    2005-01-01

    We introduce the notions of multiplier C*-category and continuous bundle of C*-categories, as the categorical analogues of the corresponding C*-algebraic notions. Every symmetric tensor C*-category with conjugates is a continuous bundle of C*-categories, with base space the spectrum of the C*-algebra associated with the identity object. We classify tensor C*-categories with fibre the dual of a compact Lie group in terms of suitable principal bundles. This also provides a classification for ce...

  2. Crystallization and preliminary X-ray analysis of a C-terminal fragment of FlgJ, a putative flagellar rod cap protein from Salmonella

    International Nuclear Information System (INIS)

    Kikuchi, Yuki; Matsunami, Hideyuki; Yamane, Midori; Imada, Katsumi; Namba, Keiichi

    2008-01-01

    A C-terminal fragment of Salmonella FlgJ, FlgJ 120–316 , which has peptidoglycan-hydrolysing activity, has been overproduced, purified and crystallized and the crystals have been characterized by X-ray diffraction. The formation of the bacterial flagellar axial structure, including the filament, the hook and the rod, requires the attachment of a cap complex to the distal end of the growing structure. Because the rod penetrates the peptidoglycan (PG) layer, the rod cap complex is thought to have PG-hydrolyzing activity. FlgJ is a putative rod cap protein whose C-terminal region shows sequence similarity to known muramidases. In this study, FlgJ 120–316 , a C-terminal fragment of FlgJ which contains the muramidase region, was overproduced, purified and crystallized. Crystals were obtained by the sitting-drop vapour-diffusion technique using PEG 3350 as a crystallizing agent and belonged to the orthorhombic space group P2 1 2 1 2 1 , with unit-cell parameters a = 38.8, b = 43.9, c = 108.5 Å. Anomalous difference Patterson maps calculated from the diffraction data set of a selenomethionine-labelled crystal showed significant peaks in the Harker sections, indicating that the data were suitable for structure determination

  3. Evaluation of bundle duct interaction by out of pile compressive test of FBR bundles. FFTF type bundle

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, Kosuke; Yamamoto, Yuji; Nagamine, Tsuyoshi; Maeda, Koji [Japan Nuclear Cycle Development Inst., Oarai, Ibaraki (Japan). Oarai Engineering Center

    2000-10-01

    Bundle duct interaction (BDI) caused by expansion of fuel pin bundle becomes one of the main limiting factors for fuel life times. Then, it is important for the design of fast reactor fuel assembly to understand the BDI behavior in detail. In order to understand the BDI behavior, out of pile compressive tests were conducted for FFTF type bundle by use of X-ray CT equipment. In these compressive tests, two type bundles with different accuracy of initial wire position were conducted. The objective of this test is to evaluate the influence of the initial error from standard position of wire at the same axial position. The locations of the pins and the duct flats are analyzed from CT image data. Quantitative evaluation was performed at the CT image data and discussed the bundle deformation status under BDI condition. Following results are obtained. 1) The accuracy of initial wire position is strongly depends on the pin-to-duct contact behavior. In the case of bundle with large error from standard position, pin-to-duct contact is delayed. 2) The BDI mitigation of the bundle with small error from standard wire position is following: The elastic ovality is the dominant deformation in mild BDI condition, then the wire dispersion and pin dispersion are occurred in severe BDI condition. 3) The BDI mitigation of the bundle with large error from standard wire position is following: The elastic ovality and local bowing of pins with large error from standard wire position are occurred in mild BDI condition, then pin dispersion is occurred around pins with large error from standard wire position, finally wire dispersion is occurred in severe BDI condition. 4) The existence of pins with large error from standard wire position is effective to delay the pin-to-duct contact, but the existence of these pins is possible to contact of pin- to- pin. (author)

  4. Unique ATPase site architecture triggers cis-mediated synchronized ATP binding in heptameric AAA+-ATPase domain of flagellar regulatory protein FlrC.

    Science.gov (United States)

    Dey, Sanjay; Biswas, Maitree; Sen, Udayaditya; Dasgupta, Jhimli

    2015-04-03

    Bacterial enhancer-binding proteins (bEBPs) oligomerize through AAA(+) domains and use ATP hydrolysis-driven energy to isomerize the RNA polymerase-σ(54) complex during transcriptional initiation. Here, we describe the first structure of the central AAA(+) domain of the flagellar regulatory protein FlrC (FlrC(C)), a bEBP that controls flagellar synthesis in Vibrio cholerae. Our results showed that FlrC(C) forms heptamer both in nucleotide (Nt)-free and -bound states without ATP-dependent subunit remodeling. Unlike the bEBPs such as NtrC1 or PspF, a novel cis-mediated "all or none" ATP binding occurs in the heptameric FlrC(C), because constriction at the ATPase site, caused by loop L3 and helix α7, restricts the proximity of the trans-protomer required for Nt binding. A unique "closed to open" movement of Walker A, assisted by trans-acting "Glu switch" Glu-286, facilitates ATP binding and hydrolysis. Fluorescence quenching and ATPase assays on FlrC(C) and mutants revealed that although Arg-349 of sensor II, positioned by trans-acting Glu-286 and Tyr-290, acts as a key residue to bind and hydrolyze ATP, Arg-319 of α7 anchors ribose and controls the rate of ATP hydrolysis by retarding the expulsion of ADP. Heptameric state of FlrC(C) is restored in solution even with the transition state mimicking ADP·AlF3. Structural results and pulldown assays indicated that L3 renders an in-built geometry to L1 and L2 causing σ(54)-FlrC(C) interaction independent of Nt binding. Collectively, our results underscore a novel mechanism of ATP binding and σ(54) interaction that strives to understand the transcriptional mechanism of the bEBPs, which probably interact directly with the RNA polymerase-σ(54) complex without DNA looping. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  5. Nuclear fuel bundle disassembly and assembly tool

    International Nuclear Information System (INIS)

    Yates, J.; Long, J.W.

    1975-01-01

    A nuclear power reactor fuel bundle is described which has a plurality of tubular fuel rods disposed in parallel array between two transverse tie plates. It is secured against disassembly by one or more locking forks which engage slots in tie rods which position the transverse plates. Springs mounted on the fuel and tie rods are compressed when the bundle is assembled thereby maintaining a continual pressure against the locking forks. Force applied in opposition to the springs permits withdrawal of the locking forks so that one tie plate may be removed, giving access to the fuel rods. An assembly and disassembly tool facilitates removal of the locking forks when the bundle is to be disassembled and the placing of the forks during assembly of the bundle. (U.S.)

  6. In-pool damaged fuel bundle recovery

    International Nuclear Information System (INIS)

    Piascik, T.G.; Patenaude, R.S.

    1988-01-01

    While preparing to rerack the Oyster Creek Nuclear Generating Station, GPU Nuclear had need to move a damaged fuel bundle. This bundle had no upper tie plate and could not be moved in the normal manner. GPU Nuclear formed a small, dedicated project team to disassemble, package and move this damaged bundle. The team was composed of key personnel from GPU Nuclear Fuels Projects, OCNGS Operations and Proto-Power / Bisco, a specialty contractor who has fuel bundle reconstitution and rod consolidation experience, remote tooling, underwater video systems and experienced technicians. Proven tooling, clear procedures and a simple approach were important, but the key element was the spirit of teamwork and leadership exhibited by the people involved

  7. In-pool damaged fuel bundle recovery

    International Nuclear Information System (INIS)

    Piascik, T.G.; Patenaude, R.S.

    1988-01-01

    While preparing to rerack the Oyster Creek Nuclear Generating Station, GPU Nuclear had need to move a damaged fuel bundle. This bundle had no upper tie plate and could not be moved in the normal manner. GPU Nuclear formed a small, dedicated project team to disassemble, package, and move this damaged bundle. The team was composed of key personnel from GPU Nuclear Fuels Projects, OCNGS Operations and Proto-Power/Bisco, a specialty contractor who has fuel bundle reconstitution and rod consolidation experience, remote tooling, underwater video systems and experienced technicians. Proven tooling, clear procedures and a simple approach were important, but the key element was the spirit of teamwork and leadership exhibited by the people involved. In spite of several emergent problems which a task of this nature presents, this small, close knit utility/vendor team completed the work on schedule and within the exposure and cost budgets

  8. Multiple large filament bundles observed in Caulobacter crescentus by electron cryotomography

    DEFF Research Database (Denmark)

    Briegel, A; Dias, DP; Li, Z

    2006-01-01

    While the absence of any cytoskeleton was once recognized as a distinguishing feature of prokaryotes, it is now clear that a number of different bacterial proteins do form filaments in vivo. Despite the critical roles these proteins play in cell shape, genome segregation and cell division...... on shape and location, referred to here as 'inner curvature', 'cytoplasmic', 'polar' and 'ring-like'. In an attempt to identify at least some of the filaments, we imaged cells where crescentin and MreB filaments would not be present. The inner curvature and cytoplasmic bundles persisted, which together...... with their localization patterns, suggest that they are composed of as-yet unidentified cytoskeletal proteins. Thus bacterial filaments are frequently found as bundles, and their variety and abundance is greater than previously suspected....

  9. Group Coupons: Interpersonal Bundling on the Internet

    OpenAIRE

    Yongmin Chen; Tianle Zhang

    2012-01-01

    Sellers sometimes offer goods for sale under both a regular price and a discount for group purchase if the consumer group reaches some minimum size. This selling practice, which we term interpersonal bundling, has been popularized on the Internet by companies such as Groupon. We explain why interpersonal bundling is a profitable strategy in the presence of demand uncertainty, and how it may further boost profits by stimulating product information dissemination. Other reasons for its profitabi...

  10. A Brief Survey of Higgs Bundles

    OpenAIRE

    Zúñiga-Rojas, Ronald Alberto

    2018-01-01

    Considering a compact Riemann surface of genus greater than two, a Higgs~bundle is a pair composed of a holomorphic bundle over the Riemann surface, joint with an auxiliar vector field, so-called Higgs field. This theory started around thirty years ago, with Hitchin's work, when he reduced the self-duality equations from dimension four to dimension two, and so, studied those equations over Riemann surfaces. Hitchin baptized those fields as "Higgs fields" beacuse in the context of physics and ...

  11. Frobenius splitting of projective toric bundles

    Indian Academy of Sciences (India)

    He Xin

    2018-03-19

    Mar 19, 2018 ... Firstly it is easy to see that the image of s under the restriction map (2.5) falls in the χ-isotypical component of (Uσ , E), i.e. for all t ∈ T .... σ falls in the χ-isotypical component of (E,Uσ ). D. As mentioned in Remark 2.3, for a vector v .... The determinant of a toric bundle. LetE be a toric bundle on a toric variety X ...

  12. Dynamic behaviour of FBR fuel pin bundles

    International Nuclear Information System (INIS)

    Martin, P.H.; Van Dorsselaere, J.P.; Ravenet, A.

    1990-01-01

    A programme of shock tests on a fast neutron reactor subassembly model (SPX1 geometry) including a complete bundle of fuel pins (dummy elements) is being carried out in the BELIER test facility at Cadarache. The purpose of these tests is: to determine the distribution of dynamic forces applied to the fuel rod clads under the impact conditions encountered in a reactor during a earthquake; to reduce as much as possible the conservatism of the methods presently used for the calculation of those forces. The test programme, now being completed, consists of the following steps: impacts on the mock-up in air with an non-compact bundle (situation of the subassembly at beginning of life (BOL) with clearances within the bundle); impacts under the same conditions but with fluid (water) in the subassembly; impacts on the mock-up in air and with a compacted bundle (simulating the conditions of an end-of-life (EOL) bundle with no clearance within the bundle). The accelerations studied in these tests cover the range encountered in design calculations for the subassembly frequencies in beam mode. (author)

  13. The Lipid Raft Proteome of African Trypanosomes Contains Many Flagellar Proteins.

    Science.gov (United States)

    Sharma, Aabha I; Olson, Cheryl L; Engman, David M

    2017-08-24

    Lipid rafts are liquid-ordered membrane microdomains that form by preferential association of 3-β-hydroxysterols, sphingolipids and raft-associated proteins often having acyl modifications. We isolated lipid rafts of the protozoan parasite Trypanosoma brucei and determined the protein composition of lipid rafts in the cell. This analysis revealed a striking enrichment of flagellar proteins and several putative signaling proteins in the lipid raft proteome. Calpains and intraflagellar transport proteins, in particular, were found to be abundant in the lipid raft proteome. These findings provide additional evidence supporting the notion that the eukaryotic cilium/flagellum is a lipid raft-enriched specialized structure with high concentrations of sterols, sphingolipids and palmitoylated proteins involved in environmental sensing and cell signaling.

  14. Testing the time-of-flight model for flagellar length sensing.

    Science.gov (United States)

    Ishikawa, Hiroaki; Marshall, Wallace F

    2017-11-07

    Cilia and flagella are microtubule-based organelles that protrude from the surface of most cells, are important to the sensing of extracellular signals, and make a driving force for fluid flow. Maintenance of flagellar length requires an active transport process known as intraflagellar transport (IFT). Recent studies reveal that the amount of IFT injection negatively correlates with the length of flagella. These observations suggest that a length-dependent feedback regulates IFT. However, it is unknown how cells recognize the length of flagella and control IFT. Several theoretical models try to explain this feedback system. We focused on one of the models, the "time-of-flight" model, which measures the length of flagella on the basis of the travel time of IFT protein in the flagellar compartment. We tested the time-of-flight model using Chlamydomonas dynein mutant cells, which show slower retrograde transport speed. The amount of IFT injection in dynein mutant cells was higher than that in control cells. This observation does not support the prediction of the time-of-flight model and suggests that Chlamydomonas uses another length-control feedback system rather than that described by the time-of-flight model. © 2017 Ishikawa and Marshall. This article is distributed by The American Society for Cell Biology under license from the author(s). Two months after publication it is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License (http://creativecommons.org/licenses/by-nc-sa/3.0).

  15. Evidence for loss of a partial flagellar glycolytic pathway during trypanosomatid evolution.

    Directory of Open Access Journals (Sweden)

    Robert W B Brown

    Full Text Available Classically viewed as a cytosolic pathway, glycolysis is increasingly recognized as a metabolic pathway exhibiting surprisingly wide-ranging variations in compartmentalization within eukaryotic cells. Trypanosomatid parasites provide an extreme view of glycolytic enzyme compartmentalization as several glycolytic enzymes are found exclusively in peroxisomes. Here, we characterize Trypanosoma brucei flagellar proteins resembling glyceraldehyde-3-phosphate dehydrogenase (GAPDH and phosphoglycerate kinase (PGK: we show the latter associates with the axoneme and the former is a novel paraflagellar rod component. The paraflagellar rod is an essential extra-axonemal structure in trypanosomes and related protists, providing a platform into which metabolic activities can be built. Yet, bioinformatics interrogation and structural modelling indicate neither the trypanosome PGK-like nor the GAPDH-like protein is catalytically active. Orthologs are present in a free-living ancestor of the trypanosomatids, Bodo saltans: the PGK-like protein from B. saltans also lacks key catalytic residues, but its GAPDH-like protein is predicted to be catalytically competent. We discuss the likelihood that the trypanosome GAPDH-like and PGK-like proteins constitute molecular evidence for evolutionary loss of a flagellar glycolytic pathway, either as a consequence of niche adaptation or the re-localization of glycolytic enzymes to peroxisomes and the extensive changes to glycolytic flux regulation that accompanied this re-localization. Evidence indicating loss of localized ATP provision via glycolytic enzymes therefore provides a novel contribution to an emerging theme of hidden diversity with respect to compartmentalization of the ubiquitous glycolytic pathway in eukaryotes. A possibility that trypanosome GAPDH-like protein additionally represents a degenerate example of a moonlighting protein is also discussed.

  16. Deformations of the generalised Picard bundle

    International Nuclear Information System (INIS)

    Biswas, I.; Brambila-Paz, L.; Newstead, P.E.

    2004-08-01

    Let X be a nonsingular algebraic curve of genus g ≥ 3, and let Mξ denote the moduli space of stable vector bundles of rank n ≥ 2 and degree d with fixed determinant ξ over X such that n and d are coprime. We assume that if g = 3 then n ≥ 4 and if g = 4 then n ≥ 3, and suppose further that n 0 , d 0 are integers such that n 0 ≥ 1 and nd 0 + n 0 d > nn 0 (2g - 2). Let E be a semistable vector bundle over X of rank n 0 and degree d 0 . The generalised Picard bundle W ξ (E) is by definition the vector bundle over M ξ defined by the direct image p M ξ *(U ξ x p X * E) where U ξ is a universal vector bundle over X x M ξ . We obtain an inversion formula allowing us to recover E from W ξ (E) and show that the space of infinitesimal deformations of W ξ (E) is isomorphic to H 1 (X, End(E)). This construction gives a locally complete family of vector bundles over M ξ parametrised by the moduli space M(n 0 ,d 0 ) of stable bundles of rank n 0 and degree d 0 over X. If (n 0 ,d 0 ) = 1 and W ξ (E) is stable for all E is an element of M(n 0 ,d 0 ), the construction determines an isomorphism from M(n 0 ,d 0 ) to a connected component M 0 of a moduli space of stable sheaves over M ξ . This applies in particular when n 0 = 1, in which case M 0 is isomorphic to the Jacobian J of X as a polarised variety. The paper as a whole is a generalisation of results of Kempf and Mukai on Picard bundles over J, and is also related to a paper of Tyurin on the geometry of moduli of vector bundles. (author)

  17. NIF laser bundle review. Final report

    International Nuclear Information System (INIS)

    Tietbohl, G.L.; Larson, D.W.; Erlandson, A.C.

    1995-01-01

    We performed additional bundle review effort subsequent to the completion of the preliminary report and are revising our original recommendations. We now recommend that the NIF baseline laser bundle size be changed to the 4x2 bundle configuration. There are several 4x2 bundle configurations that could be constructed at a cost similar to that of the baseline 4x12 (from $11M more to about $11M less than the baseline; unescalated, no contingency) and provide significant system improvements. We recommend that the building cost estimates (particularly for the in-line building options) be verified by an architect/engineer (A/E) firm knowledgeable about building design. If our cost estimates of the in-line building are accurate and therefore result in a change from the baseline U-shaped building layout, the acceptability of the in-line configuration must be reviewed from an operations viewpoint. We recommend that installation, operation, and maintenance of all laser components be reviewed to better determine the necessity of aisles, which add to the building cost significantly. The need for beam expansion must also be determined since it affects the type of bundle packing that can be used and increases the minimum laser bay width. The U-turn laser architecture (if proven viable) offers a reduction in building costs since this laser design is shorter than the baseline switched design and requires a shorter laser bay

  18. CRIS-a novel cAMP-binding protein controlling spermiogenesis and the development of flagellar bending.

    Directory of Open Access Journals (Sweden)

    Anke Miriam Krähling

    Full Text Available The second messengers cAMP and cGMP activate their target proteins by binding to a conserved cyclic nucleotide-binding domain (CNBD. Here, we identify and characterize an entirely novel CNBD-containing protein called CRIS (cyclic nucleotide receptor involved in sperm function that is unrelated to any of the other members of this protein family. CRIS is exclusively expressed in sperm precursor cells. Cris-deficient male mice are either infertile due to a lack of sperm resulting from spermatogenic arrest, or subfertile due to impaired sperm motility. The motility defect is caused by altered Ca(2+ regulation of flagellar beat asymmetry, leading to a beating pattern that is reminiscent of sperm hyperactivation. Our results suggest that CRIS interacts during spermiogenesis with Ca(2+-regulated proteins that--in mature sperm--are involved in flagellar bending.

  19. Catheter Associated Urinary Tract Infection Prevention bundle

    Directory of Open Access Journals (Sweden)

    O. Zarkotou

    2017-01-01

    Full Text Available Catheter-associated urinary tract infections (CAUTI are among the most common healthcare-associated infections, and potentially lead to significant morbidity and mortality. Multifaceted infection control strategies implemented as bundles can prevent nosocomial infections associated with invasive devices such as CAUTIs. The components of the CAUTI bundle proposed herein, include appropriate indications for catheterization and recommendations for the procedures of catheter insertion and catheter maintenance and care. Avoiding unnecessary urinary catheter use is the most effective measure for their prevention. To minimize the risk of CAUTI, urinary catheters should be placed only when a clinical valid indication is documented and they should be removed as soon as possible; alternatives to catheterization should also be considered. Aseptic insertion technique, maintenance of closed drainage system and strict adherence to hand hygiene are essential for preventing CAUTI. The successful implementation of the bundle requires education and training for all healthcare professionals and evaluation of surveillance data.

  20. Development of CANDU advanced fuel bundle

    International Nuclear Information System (INIS)

    Suk, H. C.; Hwang, W.; Rhee, B. W.; Jung, S. H.; Chung, C. H.

    1992-05-01

    This research project is underway in cooperation with AECL to develop the CANDU advanced fuel bundle (so-called, CANFLEX) which can enhance reactor safety and fuel economy in comparison with the current CANDU fuel and which can be used with natural uranium, slightly enriched uranium and other advanced fuel cycle. As the final schedule, the advanced fuel will be verified by carrying out a large scale demonstration of the bundle irradiation in a commercial CANDU reactor for 1996 and 1997, and consequently will be used in the existing and future CANDU reactors in Korea. The research activities during this year include the detail design of CANFLEX fuel with natural enriched uranium (CANFLEX-NU). Based on this design, CANFLEX fuel was mocked up. Out-of-pile hydraulic scoping tests were conducted with the fuel in the CANDU Cold Test Loop to investigate the condition under which maximum pressure drop occurs and the maximum value of the bundle pressure drop. (Author)

  1. Extensive flagellar remodeling during the complex life cycle of &ITParatrypanosoma&IT, an early-branching trypanosomatid

    Czech Academy of Sciences Publication Activity Database

    Skalický, Tomáš; Dobáková, Eva; Wheeler, R. J.; Tesařová, Martina; Flegontov, P.; Jirsová, Dagmar; Votýpka, Jan; Yurchenko, V.; Ayala, F. J.; Lukeš, Julius

    2017-01-01

    Roč. 114, č. 44 (2017), s. 11757-11762 ISSN 0027-8424 R&D Projects: GA ČR(CZ) GA14-23986S; GA MŠk LL1601; GA MŠk(CZ) LM2015062 Institutional support: RVO:60077344 Keywords : trypanosomatid * evolution * flagellar remodeling * haptomonads * cytostome Subject RIV: EB - Genetics ; Molecular Biology OBOR OECD: Biology (theoretical, mathematical, thermal, cryobiology, biological rhythm), Evolutionary biology Impact factor: 9.661, year: 2016

  2. Deduction of upstream sequences of Xanthomonas campestris flagellar genes responding to transcription activation by FleQ

    International Nuclear Information System (INIS)

    Hu, R.-M.; Yang, T.-C.; Yang, S.-H.; Tseng, Y.-H.

    2005-01-01

    Xanthomonas campestris pv. campestris (Xcc), a close relative to Pseudomonas aeruginosa, is the pathogen causing black rot in cruciferous plants. In P. aeruginosa, FleQ serves as a cognate activator of σ 54 in transcription from several σ 54 -dependent promoters of flagellar genes. These P. aeruginosa promoters have been analyzed for FleQ-binding sequences; however, no consensus was deduced. Xcc, although lacks fleSR, has a fleQ homologue residing among over 40 contiguously clustered flagellar genes. A fleQ mutant, Xc17fleQ, constructed by insertional mutation is deficient in FleQ protein, non-flagellated, and immobile. Transcriptional fusion assays on six putative σ 54 -dependent promoters of the flagellar genes, fliE, fliQ, fliL, flgG, flgB, and flhF, indicated that each of them is also FleQ dependent. Each of these promoters has a sequence with weak consensus to 5'-gaaacCCgccgCcgctTt-3', immediately upstream of the predicted σ 54 -binding site, with an imperfect inverted repeat containing a GC-rich center flanked by several A and T at 5'- and 3'-ends, respectively. Replacing this region in fliE promoter with a HindIII recognition sequence abolished the transcription, indicating that this region responds to transcription activation by FleQ

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

    Science.gov (United States)

    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

  4. Immunological reactions to Salmonella FlgK and FliD flagellar proteins by broiler sera

    Science.gov (United States)

    Background: Salmonella is the leading foodborne pathogen that causes human acute bacterial gastroenteritis worldwide. Chickens are considered as one of major reservoirs of this bacterium. Because the bacterial flagellum is involved in motility, adhesion, quorum sensing and other virulence activit...

  5. Polyelectrolyte Bundles: Finite size at thermodynamic equilibrium?

    Science.gov (United States)

    Sayar, Mehmet

    2005-03-01

    Experimental observation of finite size aggregates formed by polyelectrolytes such as DNA and F-actin, as well as synthetic polymers like poly(p-phenylene), has created a lot of attention in recent years. Here, bundle formation in rigid rod-like polyelectrolytes is studied via computer simulations. For the case of hydrophobically modified polyelectrolytes finite size bundles are observed even in the presence of only monovalent counterions. Furthermore, in the absence of a hydrophobic backbone, we have also observed formation of finite size aggregates via multivalent counterion condensation. The size distribution of such aggregates and the stability is analyzed in this study.

  6. Bundled payment and enhanced recovery after surgery.

    Science.gov (United States)

    Huang, Jeffrey

    2015-01-01

    Medicare's fee-for-service (FFS) payment model may contribute to unsustainable spending growth. Payers are turning to alternative payment methods. The leading alternative payment model to the FFS problem is bundled payment. The Centers for Medicare & Medicaid Services (CMS) is taking another step to improve healthcare quality at lower cost. The CMS's Center for Medicare and Medicaid Innovation developed four models of bundled payments and 48 discrete clinical condition episodes. Many surgical care procedures are included in the 48 different clinical condition episodes.

  7. Direct His bundle pacing post AVN ablation.

    Science.gov (United States)

    Lakshmanadoss, Umashankar; Aggarwal, Ashim; Huang, David T; Daubert, James P; Shah, Abrar

    2009-08-01

    Atrioventricular nodal (AVN) ablation with concomitant pacemaker implantation is one of the strategies that reduce symptoms in patients with atrial fibrillation (AF). However, the long-term adverse effects of right ventricular (RV) apical pacing have led to the search for alternating sites of pacing. Biventricular pacing produces a significant improvement in functional capacity over RV pacing in patients undergoing AVN ablation. Another alternative site for pacing is direct His bundle to reduce the adverse outcome of RV pacing. Here, we present a case of direct His bundle pacing using steerable lead delivery system in a patient with symptomatic paroxysmal AF with concurrent AVN ablation.

  8. Genetical and functional investigation of fliC genes encoding flagellar serotype H4 in wildtype strains of Escherichia coli and in a laboratory E. coli K-12 strain expressing flagellar antigen type H48

    Directory of Open Access Journals (Sweden)

    Schaudinn Christoph

    2005-01-01

    Full Text Available Abstract Background Serotyping of O-(lipopolysaccharide and H-(flagellar antigens is a wideley used method for identification of pathogenic strains and clones of Escherichia coli. At present, 176 O- and 53 H-antigens are described for E. coli which occur in different combinations in the strains. The flagellar antigen H4 is widely present in E. coli strains of different O-serotypes and pathotypes and we have investigated the genetic relationship between H4 encoding fliC genes by PCR, nucleotide sequencing and expression studies. Results The complete nucleotide sequence of fliC genes present in E. coli reference strains U9-41 (O2:K1:H4 and P12b (O15:H17 was determined and both were found 99.3% (1043 of 1050 nucleotides identical in their coding sequence. A PCR/RFLP protocol was developed for typing of fliC-H4 strains and 88 E. coli strains reacting with H4 antiserum were investigated. Nucleotide sequencing of complete fliC genes of six E. coli strains which were selected based on serum agglutination titers, fliC-PCR genotyping and reference data revealed 96.6 to 100% identity on the amino acid level. The functional expression of flagellin encoded by fliC-H4 from strain U9-41 and from our strain P12b which is an H4 expressing variant type was investigated in the E. coli K-12 strain JM109 which encodes flagellar type H48. The fliC recombinant plasmid carrying JM109 strains reacted with both H4 and H48 specific antisera whereas JM109 reacted only with the H48 antiserum. By immunoelectron microscopy, we could show that the flagella made by the fliC-H4 recombinant plasmid carrying strain are constituted of H48 and H4 flagellins which are co-assembled into functional flagella. Conclusion The flagellar serotype H4 is encoded by closely related fliC genes present in serologically different types of E. coli strainswhich were isolated at different time periods and geographical locations. Our expression studies show for the first time, that flagellins of

  9. Bacterial meningitis

    NARCIS (Netherlands)

    Roos, Karen L.; van de Beek, Diederik

    2010-01-01

    Bacterial meningitis is a neurological emergency. Empiric antimicrobial and adjunctive therapy should be initiated as soon as a single set of blood cultures has been obtained. Clinical signs suggestive of bacterial meningitis include fever, headache, meningismus, vomiting, photophobia, and an

  10. Characteristics of CANDU fuel bundles that caused pressure tube fretting at the bundle midplane

    Energy Technology Data Exchange (ETDEWEB)

    Dennier, D; Manzer, A M [Atomic Energy of Canada Ltd., Mississauga, ON (Canada); Koehn, E [Ontario Hydro, Toronto, ON (Canada)

    1996-12-31

    Detailed measurements on new bundles, and those that caused fretting during in- and out-reactor tests, have given insight into the factors responsible for fretting at the midplane of the inlet bundle. Bottom fuel elements that were attached near radial endplate spokes and had inboard bearing pads in the rolled joint cavity produced a significant portion of the observed fret marks. These elements are influenced by several driving forces that deflect the centre bearing pads towards the pressure tube surface. The evidence suggests that slight changes in bundle design may be possible to reduce pressure tube fretting. (author). 4 refs., 3 tabs., 8 figs.

  11. Impact of bundle deformation on CHF: ASSERT-PV assessment of extended burnup Bruce B bundle G85159W

    International Nuclear Information System (INIS)

    Rao, Y.F.; Manzer, A.M.

    2005-01-01

    This paper presents a subchannel thermalhydraulic analysis of the effect on critical heat flux (CHF) of bundle deformation such as element bow and diametral creep. The bundle geometry is based on the post-irradiation examination (PIE) data of a single bundle from the Bruce B Nuclear Generating Station, Bruce B bundle G85159W, which was irradiated for more than two years in the core during reactor commissioning. The subchannel code ASSERT-PV IST is used to assess changes in CHF and dryout power due to bundle deformation, compared to the reference, undeformed bundle. (author)

  12. Fiber bundle geometry and space-time structure

    International Nuclear Information System (INIS)

    Nascimento, J.C.

    1977-01-01

    Within the framework of the geometric formulation of Gauge theories in fiber bundles, the general relation between the bundle connection (Gauge field) and the geometry of the base space is obtained. A possible Gauge theory for gravitation is presented [pt

  13. Automated negotiation and bundling of information goods

    NARCIS (Netherlands)

    Somefun, D.J.A.; Gerding, E.H.; Bohté, S.M.; Poutré, la J.A.; Faratin, P.; Parkes, D.; Rodriquez-Aguilar, J.

    2004-01-01

    In this paper, we present a novel system for selling bundles of news items. Through the system, customers bargain with the seller over the price and quality of the delivered goods. The advantage of the developed system is that it allows for a high degree of flexibility in the price, quality, and

  14. Jacobi bundles and the BFV-complex

    Czech Academy of Sciences Publication Activity Database

    Le, Hong-Van; Tortorella, A. G.; Vitagliano, L.

    2017-01-01

    Roč. 121, November (2017), s. 347-377 ISSN 0393-0440 Institutional support: RVO:67985840 Keywords : Jacobi manifold * Jacobi bundle * coisotropic submanifolds Subject RIV: BA - General Mathematics OBOR OECD: Pure mathematics Impact factor: 0.819, year: 2016 http://www.sciencedirect.com/science/article/pii/S0393044017301948

  15. Optimization of a bundle divertor for FED

    International Nuclear Information System (INIS)

    Hively, L.M.; Rothe, K.E.; Minkoff, M.

    1982-01-01

    Optimal double-T bundle divertor configurations have been obtained for the Fusion Engineering Device (FED). On-axis ripple is minimized, while satisfying a series of engineering constraints. The ensuing non-linear optimization problem is solved via a sequence of quadratic programming subproblems, using the VMCON algorithm. The resulting divertor designs are substantially improved over previous configurations

  16. Large eddy simulation of bundle turbulent flows

    International Nuclear Information System (INIS)

    Hassan, Y.A.; Barsamian, H.R.

    1995-01-01

    Large eddy simulation may be defined as simulation of a turbulent flow in which the large scale motions are explicitly resolved while the small scale motions are modeled. This results into a system of equations that require closure models. The closure models relate the effects of the small scale motions onto the large scale motions. There have been several models developed, the most popular is the Smagorinsky eddy viscosity model. A new model has recently been introduced by Lee that modified the Smagorinsky model. Using both of the above mentioned closure models, two different geometric arrangements were used in the simulation of turbulent cross flow within rigid tube bundles. An inlined array simulations was performed for a deep bundle (10,816 nodes) as well as an inlet/outlet simulation (57,600 nodes). Comparisons were made to available experimental data. Flow visualization enabled the distinction of different characteristics within the flow such as jet switching effects in the wake of the bundle flow for the inlet/outlet simulation case, as well as within tube bundles. The results indicate that the large eddy simulation technique is capable of turbulence prediction and may be used as a viable engineering tool with the careful consideration of the subgrid scale model. (author)

  17. Laughter-induced left bundle branch block.

    Science.gov (United States)

    Chow, Grant V; Desai, Dipan; Spragg, David D; Zakaria, Sammy

    2012-10-01

    We present the case of a patient with ischemic heart disease and intermittent left bundle branch block, reproducibly induced by laughter. Following treatment of ischemia with successful deployment of a drug-eluting stent, no further episodes of inducible LBBB were seen. Transient ischemia, exacerbated by elevated intrathoracic pressure during laughter, may have contributed to onset of this phenomenon. © 2012 Wiley Periodicals, Inc.

  18. Crystallographic and molecular dynamics analysis of loop motions unmasking the peptidoglycan-binding site in stator protein MotB of flagellar motor.

    Directory of Open Access Journals (Sweden)

    Cyril F Reboul

    Full Text Available BACKGROUND: The C-terminal domain of MotB (MotB-C shows high sequence similarity to outer membrane protein A and related peptidoglycan (PG-binding proteins. It is believed to anchor the power-generating MotA/MotB stator unit of the bacterial flagellar motor to the peptidoglycan layer of the cell wall. We previously reported the first crystal structure of this domain and made a puzzling observation that all conserved residues that are thought to be essential for PG recognition are buried and inaccessible in the crystal structure. In this study, we tested a hypothesis that peptidoglycan binding is preceded by, or accompanied by, some structural reorganization that exposes the key conserved residues. METHODOLOGY/PRINCIPAL FINDINGS: We determined the structure of a new crystalline form (Form B of Helicobacter pylori MotB-C. Comparisons with the existing Form A revealed conformational variations in the petal-like loops around the carbohydrate binding site near one end of the β-sheet. These variations are thought to reflect natural flexibility at this site required for insertion into the peptidoglycan mesh. In order to understand the nature of this flexibility we have performed molecular dynamics simulations of the MotB-C dimer. The results are consistent with the crystallographic data and provide evidence that the three loops move in a concerted fashion, exposing conserved MotB residues that have previously been implicated in binding of the peptide moiety of peptidoglycan. CONCLUSION/SIGNIFICANCE: Our structural analysis provides a new insight into the mechanism by which MotB inserts into the peptidoglycan mesh, thus anchoring the power-generating complex to the cell wall.

  19. Fiber bundles in non-relativistic quantum mechanics

    International Nuclear Information System (INIS)

    Moylan, P.

    1979-11-01

    The problem of describing a quantum-mechanical system with symmetry by a fiber bundle is considered. The quantization of a fiber bundle is introduced. Fiber bundles for the Kepler problem and the rotator are constructed. The fiber bundle concept provides a new model for a physical system: it provides a model for an elementary particle with extension having integral values of spin. 5 figures

  20. Interplanetary Overlay Network Bundle Protocol Implementation

    Science.gov (United States)

    Burleigh, Scott C.

    2011-01-01

    The Interplanetary Overlay Network (ION) system's BP package, an implementation of the Delay-Tolerant Networking (DTN) Bundle Protocol (BP) and supporting services, has been specifically designed to be suitable for use on deep-space robotic vehicles. Although the ION BP implementation is unique in its use of zero-copy objects for high performance, and in its use of resource-sensitive rate control, it is fully interoperable with other implementations of the BP specification (Internet RFC 5050). The ION BP implementation is built using the same software infrastructure that underlies the implementation of the CCSDS (Consultative Committee for Space Data Systems) File Delivery Protocol (CFDP) built into the flight software of Deep Impact. It is designed to minimize resource consumption, while maximizing operational robustness. For example, no dynamic allocation of system memory is required. Like all the other ION packages, ION's BP implementation is designed to port readily between Linux and Solaris (for easy development and for ground system operations) and VxWorks (for flight systems operations). The exact same source code is exercised in both environments. Initially included in the ION BP implementations are the following: libraries of functions used in constructing bundle forwarders and convergence-layer (CL) input and output adapters; a simple prototype bundle forwarder and associated CL adapters designed to run over an IPbased local area network; administrative tools for managing a simple DTN infrastructure built from these components; a background daemon process that silently destroys bundles whose time-to-live intervals have expired; a library of functions exposed to applications, enabling them to issue and receive data encapsulated in DTN bundles; and some simple applications that can be used for system checkout and benchmarking.

  1. CDKL5 regulates flagellar length and localizes to the base of the flagella in Chlamydomonas

    Science.gov (United States)

    Tam, Lai-Wa; Ranum, Paul T.; Lefebvre, Paul A.

    2013-01-01

    The length of Chlamydomonas flagella is tightly regulated. Mutations in four genes—LF1, LF2, LF3, and LF4—cause cells to assemble flagella up to three times wild-type length. LF2 and LF4 encode protein kinases. Here we describe a new gene, LF5, in which null mutations cause cells to assemble flagella of excess length. The LF5 gene encodes a protein kinase very similar in sequence to the protein kinase CDKL5. In humans, mutations in this kinase cause a severe form of juvenile epilepsy. The LF5 protein localizes to a unique location: the proximal 1 μm of the flagella. The proximal localization of the LF5 protein is lost when genes that make up the proteins in the cytoplasmic length regulatory complex (LRC)—LF1, LF2, and LF3—are mutated. In these mutants LF5p becomes localized either at the distal tip of the flagella or along the flagellar length, indicating that length regulation involves, at least in part, control of LF5p localization by the LRC. PMID:23283985

  2. Imaging of the 3D dynamics of flagellar beating in human sperm.

    Science.gov (United States)

    Silva-Villalobos, F; Pimentel, J A; Darszon, A; Corkidi, G

    2014-01-01

    The study of the mechanical and environmental factors that regulate a fundamental event such as fertilization have been subject of multiple studies. Nevertheless, the microscopical size of the spermatozoa and the high beating frequency of their flagella (up to 20 Hz) impose a series of technological challenges for the study of the mechanical factors implicated. Traditionally, due to the inherent characteristics of the rapid sperm movement, and to the technological limitations of microscopes (optical or confocal) to follow in three dimensions (3D) their movement, the analysis of their dynamics has been studied in two dimensions, when the head is confined to a surface. Flagella propel sperm and while their head can be confined to a surface, flagellar movement is not restricted to 2D, always displaying 3D components. In this work, we present a highly novel and useful tool to analyze sperm flagella dynamics in 3D. The basis of the method is a 100 Hz oscillating objective mounted on a bright field optical microscope covering a 16 microns depth space at a rate of ~ 5000 images per second. The best flagellum focused subregions were associated to their respective Z real 3D position. Unprecedented graphical results making evident the 3D movement of the flagella are shown in this work and supplemental material illustrating a 3D animation using the obtained experimental results is also included.

  3. Crystallization of FcpA from Leptospira, a novel flagellar protein that is essential for pathogenesis.

    Science.gov (United States)

    San Martin, Fabiana; Mechaly, Ariel E; Larrieux, Nicole; Wunder, Elsio A; Ko, Albert I; Picardeau, Mathieu; Trajtenberg, Felipe; Buschiazzo, Alejandro

    2017-03-01

    The protein FcpA is a unique component of the flagellar filament of spirochete bacteria belonging to the genus Leptospira. Although it plays an essential role in translational motility and pathogenicity, no structures of FcpA homologues are currently available in the PDB. Its three-dimensional structure will unveil the novel motility mechanisms that render pathogenic Leptospira particularly efficient at invading and disseminating within their hosts, causing leptospirosis in humans and animals. FcpA from L. interrogans was purified and crystallized, but despite laborious attempts no useful X ray diffraction data could be obtained. This challenge was solved by expressing a close orthologue from the related saprophytic species L. biflexa. Three different crystal forms were obtained: a primitive and a centred monoclinic form, as well as a hexagonal variant. All forms diffracted X-rays to suitable resolutions for crystallographic analyses, with the hexagonal type typically reaching the highest limits of 2.0 Å and better. A variation of the quick-soaking procedure resulted in an iodide derivative that was instrumental for single-wavelength anomalous diffraction methods.

  4. Deformation quantization with separation of variables of an endomorphism bundle

    OpenAIRE

    Karabegov, Alexander

    2013-01-01

    Given a holomorphic Hermitian vector bundle and a star-product with separation of variables on a pseudo-Kaehler manifold, we construct a star product on the sections of the endomorphism bundle of the dual bundle which also has the appropriately generalized property of separation of variables. For this star product we prove a generalization of Gammelgaard's graph-theoretic formula.

  5. Image-Based Edge Bundles : Simplified Visualization of Large Graphs

    NARCIS (Netherlands)

    Telea, A.; Ersoy, O.

    2010-01-01

    We present a new approach aimed at understanding the structure of connections in edge-bundling layouts. We combine the advantages of edge bundles with a bundle-centric simplified visual representation of a graph's structure. For this, we first compute a hierarchical edge clustering of a given graph

  6. Bundling of harvesting residues and whole-trees and the treatment of bundles; Hakkuutaehteiden ja kokopuiden niputus ja nippujen kaesittely

    Energy Technology Data Exchange (ETDEWEB)

    Kaipainen, H; Seppaenen, V; Rinne, S

    1997-12-31

    The conditions on which the bundling of the harvesting residues from spruce regeneration fellings would become profitable were studied. The calculations showed that one of the most important features was sufficient compaction of the bundle, so that the portion of the wood in the unit volume of the bundle has to be more than 40 %. The tests showed that the timber grab loader of farm tractor was insufficient for production of dense bundles. The feeding and compression device of the prototype bundler was constructed in the research and with this device the required density was obtained.The rate of compaction of the dry spruce felling residues was about 40 % and that of the fresh residues was more than 50 %. The comparison between the bundles showed that the calorific value of the fresh bundle per unit volume was nearly 30 % higher than that of the dry bundle. This means that the treatment of the bundles should be done of fresh felling residues. Drying of the bundles succeeded well, and the crushing and chipping tests showed that the processing of the bundles at the plant is possible. The treatability of the bundles was also excellent. By using the prototype, developed in the research, it was possible to produce a bundle of the fresh spruce harvesting residues, the diameter of which was about 50 cm and the length about 3 m, and the rate of compaction over 50 %. By these values the reduction target of the costs is obtainable

  7. Bundling of harvesting residues and whole-trees and the treatment of bundles; Hakkuutaehteiden ja kokopuiden niputus ja nippujen kaesittely

    Energy Technology Data Exchange (ETDEWEB)

    Kaipainen, H.; Seppaenen, V.; Rinne, S.

    1996-12-31

    The conditions on which the bundling of the harvesting residues from spruce regeneration fellings would become profitable were studied. The calculations showed that one of the most important features was sufficient compaction of the bundle, so that the portion of the wood in the unit volume of the bundle has to be more than 40 %. The tests showed that the timber grab loader of farm tractor was insufficient for production of dense bundles. The feeding and compression device of the prototype bundler was constructed in the research and with this device the required density was obtained.The rate of compaction of the dry spruce felling residues was about 40 % and that of the fresh residues was more than 50 %. The comparison between the bundles showed that the calorific value of the fresh bundle per unit volume was nearly 30 % higher than that of the dry bundle. This means that the treatment of the bundles should be done of fresh felling residues. Drying of the bundles succeeded well, and the crushing and chipping tests showed that the processing of the bundles at the plant is possible. The treatability of the bundles was also excellent. By using the prototype, developed in the research, it was possible to produce a bundle of the fresh spruce harvesting residues, the diameter of which was about 50 cm and the length about 3 m, and the rate of compaction over 50 %. By these values the reduction target of the costs is obtainable

  8. Comparison of ASSERT subchannel code with Marviken bundle data

    International Nuclear Information System (INIS)

    Tahir, A.; Carver, M.B.

    1984-04-01

    In this paper ASSERT predictions are compared with the Marviken 6-rod bundle and 36+1 rod bundle. The predictions are presented for two experiments in the 6-rod bundle and four experiments in the 36+1 rod bundle. For low inlet subcooling, the void predictions are in good agreement with the experimental data. For high inlet subcooling, however, the agreement is not as good. This is attributed to the fact that in the high inlet subcooling experiments, single phase turbulent mixing plays a more important role in determining flow conditions in the bundle

  9. Triviality and Split of Vector Bundles on Rationally Connected Varieties

    OpenAIRE

    Pan, Xuanyu

    2013-01-01

    In this paper, we give a simple proof of a triviality criterion due to I.Biswas and J.Pedro and P.Dos Santos. We also prove a vector bundle on a homogenous space is trivial if and only if the restrictions of the vector bundle to Schubert lines are trivial. Using this result and Chern classes of vector bundles, we give a general criterion of a uniform vector bundle on a homogenous space to be splitting. As an application, we prove a uniform vector bundle on classical Grassmannians and quadrics...

  10. Rod bundle burnout data and correlation comparisons

    International Nuclear Information System (INIS)

    Yoder, G.L.; Morris, D.G.; Mullins, C.B.

    1985-01-01

    Rod bundle burnout data from 30 steady-state and 3 transient tests were obtained from experiments performed in the Thermal Hydraulic Test Facility at the Oak Ridge National Laboratory. The tests covered a parameter range relevant to intact core reactor accidents ranging from large break to small break loss-ofcoolant conditions. Instrumentation within the 64-rod test section indicated that burnout occurred over an axial range within the bundle. The distance from the point where the first dry rod was detected to the point where all rods were dry was up to 60 cm in some of the tests. The burnout data should prove useful in developing new correlations for use in reactor thermalhydraulic codes. Evaluation of several existing critical heat flux correlations using the data show that three correlations, the Barnett, Bowring, and Katto correlations, perform similarly and correlate the data better than the Biasi correlation

  11. The turbulent flow in rod bundles

    International Nuclear Information System (INIS)

    Moeller, S.V.

    1989-01-01

    Experimental studies have shown that the axial and azimuthal turbulence intensities in the gap regions of rod bundles increase strongly with decreasing rod spacing; the fluctuating velocities in the axial and azimuthal directions have a quasi-periodic behaviour. To determine the origin of this phenomenon, an its characteristics as a function of the geometry and the Reynolds number, an experimental investigation was performed on the turbulent in several rod bundles with different aspect ratios (P/D, W/D). Hot-wires and microsphones were used for the measurements of velocity and wall pressure fluctuations. The data were evaluated to obtain spectra as well as auto and cross correlations. Based on the results, a phenomenological model is presented to explain this phenomenon. By means of the model, the mass exchange between neighbouring subchannels is explained [pt

  12. Reactor application of an improved bundle divertor

    International Nuclear Information System (INIS)

    Yang, T.F.; Ruck, G.W.; Lee, A.Y.; Smeltzer, G.; Prevenslik, T.

    1978-11-01

    A Bundle Divertor was chosen as the impurity control and plasma exhaust system for the beam driven Demonstration Tokamak Hybrid Reactor - DTHR. In the context of a preconceptual design study of the reactor and associated facility a bundle divertor concept was developed and integrated into the reactor system. The overall system was found feasible and scalable for reactors with intermediate torodial field strengths on axis. The important design characteristics are: the overall average current density of the divertor coils is 0.73 kA for each tesla of toroidal field on axis; the divertor windings are made from super-conducting cables supported by steel structures and are designed to be maintainable; the particle collection assembly and auxiliary cryosorption vacuum pump are dual systems designed such that they can be reactivated alterntively to allow for continuous reactor operation; and the power requirement for energizing and operating the divertor is about 5 MW

  13. On stability of Kummer surfaces' tangent bundle

    International Nuclear Information System (INIS)

    Bozhkov, Y.D.

    1988-10-01

    In this paper we propose an explicit approximation of the Kaehler-Einstein-Calabi-Yau metric on the Kummer surfaces, which are manifolds of type K3. It is constructed by gluing 16 pieces of the Eguchi-Hanson metric and 16 pieces of the Euclidean metric. Two estimates on its curvature are proved. Then we prove an estimate on the first eigenvalue of a covariant differential operator of second order. This enables us to apply Taubes' iteration procedure to obtain that there exists an anti-self-dual connection on the considered Kummer surface. In fact, it is a Hermitian-Einstein connection from which we conclude that Kummer surfaces' co-tangent bundle is stable and therefore their tangent bundle is stable too. (author). 40 refs

  14. SIKAP KONSUMEN TERHADAP PRODUK BUNDLING AGRIBISNIS

    Directory of Open Access Journals (Sweden)

    Didi Junaedi

    2017-04-01

    implementation to Dekalb brand hybrid corn and Round-up brand herbicide. By analyzes how consumer attitudes toward buying intention in this regard farmers as buyer and retailers as products services. The data used is primary data. Primary data is obtained using 2 kind of respondents are retailers and farmers. The data obtained by distributed 30 questionnaires for retailers and 110 farmers in Grobogan. The descriptive statistic employed to analyzed data by using multiple linear regressions with t test, F test and coefficient of determination. The result showed that on retailers respondents attribute the product bundling has no significant influence to consumer buying intention but consumer attitudes significantly influence the buying intention. On the farmers respondents showed that attributes of the product bundling and consumer attitudes positive and significant influence to buying intention.

  15. Tube bundle vibrations in transversal flow

    International Nuclear Information System (INIS)

    Gibert, R.J.; Sagner, M.

    1978-01-01

    This study gives important information concerning characteristic parameters about lock-in and whirling instability phenomena, in the case of tube arrays. The work is mainly an experimental one though models are also developed: 1) an equilateral pitch bundle (p=1,5 D with D=tube diameter) is tested. Tube damping (epsilon) and first eigenfrequency (f), flow velocity are explored in a large domain. Vibratory level of the tubes are measured and critical points are ploted on the fluidelastic parameters diagram. Several bundles with various usual pitches and arrangements (in line or staggered) are tested. Critical velocities are measured and the whirling instability characteristic coefficient is tabulated. A complementary experiment is made on tube rows with various pitches. This gives valuable informations concerning the look-in domain in VR and A'R diagram. Furthermore this puts in evidence the important effect of a frequency difference between two adjacent tubes on the whirling critical velocity

  16. Constrained ripple optimization of Tokamak bundle divertors

    International Nuclear Information System (INIS)

    Hively, L.M.; Rome, J.A.; Lynch, V.E.; Lyon, J.F.; Fowler, R.H.; Peng, Y-K.M.; Dory, R.A.

    1983-02-01

    Magnetic field ripple from a tokamak bundle divertor is localized to a small toroidal sector and must be treated differently from the usual (distributed) toroidal field (TF) coil ripple. Generally, in a tokamak with an unoptimized divertor design, all of the banana-trapped fast ions are quickly lost due to banana drift diffusion or to trapping between the 1/R variation in absolute value vector B ω B and local field maxima due to the divertor. A computer code has been written to optimize automatically on-axis ripple subject to these constraints, while varying up to nine design parameters. Optimum configurations have low on-axis ripple ( 0 ) are lost. However, because finite-sized TF coils have not been used in this study, the flux bundle is not expanded

  17. Fiber Bundle Model Under Heterogeneous Loading

    Science.gov (United States)

    Roy, Subhadeep; Goswami, Sanchari

    2018-03-01

    The present work deals with the behavior of fiber bundle model under heterogeneous loading condition. The model is explored both in the mean-field limit as well as with local stress concentration. In the mean field limit, the failure abruptness decreases with increasing order k of heterogeneous loading. In this limit, a brittle to quasi-brittle transition is observed at a particular strength of disorder which changes with k. On the other hand, the model is hardly affected by such heterogeneity in the limit where local stress concentration plays a crucial role. The continuous limit of the heterogeneous loading is also studied and discussed in this paper. Some of the important results related to fiber bundle model are reviewed and their responses to our new scheme of heterogeneous loading are studied in details. Our findings are universal with respect to the nature of the threshold distribution adopted to assign strength to an individual fiber.

  18. Are there intracellular Ca2+ oscillations correlated with flagellar beating in human sperm? A three vs. two-dimensional analysis.

    Science.gov (United States)

    Corkidi, G; Montoya, F; Hernández-Herrera, P; Ríos-Herrera, W A; Müller, M F; Treviño, C L; Darszon, A

    2017-09-01

    Are there intracellular Ca2+ ([Ca2+]i) oscillations correlated with flagellar beating in human sperm? The results reveal statistically significant [Ca2+]i oscillations that are correlated with the human sperm flagellar beating frequency, when measured in three-dimensions (3D). Fast [Ca2+]i oscillations that are correlated to the beating flagellar frequency of cells swimming in a restricted volume have been detected in hamster sperm. To date, such findings have not been confirmed in any other mammalian sperm species. An important question that has remained regarding these observations is whether the fast [Ca2+]i oscillations are real or might they be due to remaining defocusing effects of the Z component arising from the 3D beating of the flagella. Healthy donors whose semen samples fulfill the WHO criteria between the age of 18-28 were selected. Cells from at least six different donors were utilized for analysis. Approximately the same number of experimental and control cells were analyzed. Motile cells were obtained by the swim-up technique and were loaded with Fluo-4 (Ca2+ sensitive dye) or with Calcein (Ca2+ insensitive dye). Ni2+ was used as a non-specific plasma membrane Ca2+ channel blocker. Fluorescence data and flagella position were acquired in 3D. Each cell was recorded for up to 5.6 s within a depth of 16 microns with a high speed camera (coupled to an image intensifier) acquiring at a rate of 3000 frames per second, while an oscillating objective vibrated at 90 Hz via a piezoelectric device. From these samples, eight experimental and nine control sperm cells were analyzed in both 2D and 3D. We have implemented a new system that allows [Ca2+]i measurements of the human sperm flagellum beating in 3D. These measurements reveal statistically significant [Ca2+]i oscillations that correlate with the flagellar beating frequency. These oscillations may arise from intracellular sources and/or Ca2+ transporters, as they were insensitive to external Ni2+, a non

  19. Uncovering ecosystem service bundles through social preferences.

    Directory of Open Access Journals (Sweden)

    Berta Martín-López

    Full Text Available Ecosystem service assessments have increasingly been used to support environmental management policies, mainly based on biophysical and economic indicators. However, few studies have coped with the social-cultural dimension of ecosystem services, despite being considered a research priority. We examined how ecosystem service bundles and trade-offs emerge from diverging social preferences toward ecosystem services delivered by various types of ecosystems in Spain. We conducted 3,379 direct face-to-face questionnaires in eight different case study sites from 2007 to 2011. Overall, 90.5% of the sampled population recognized the ecosystem's capacity to deliver services. Formal studies, environmental behavior, and gender variables influenced the probability of people recognizing the ecosystem's capacity to provide services. The ecosystem services most frequently perceived by people were regulating services; of those, air purification held the greatest importance. However, statistical analysis showed that socio-cultural factors and the conservation management strategy of ecosystems (i.e., National Park, Natural Park, or a non-protected area have an effect on social preferences toward ecosystem services. Ecosystem service trade-offs and bundles were identified by analyzing social preferences through multivariate analysis (redundancy analysis and hierarchical cluster analysis. We found a clear trade-off among provisioning services (and recreational hunting versus regulating services and almost all cultural services. We identified three ecosystem service bundles associated with the conservation management strategy and the rural-urban gradient. We conclude that socio-cultural preferences toward ecosystem services can serve as a tool to identify relevant services for people, the factors underlying these social preferences, and emerging ecosystem service bundles and trade-offs.

  20. Principal bundles on the projective line

    Indian Academy of Sciences (India)

    M. Senthilkumar (Newgen Imaging) 1461 1996 Oct 15 13:05:22

    LetX be a complete nonsingular curve over the algebraic closurek ofk andGa reductive group over k. Let E → X be a principal G-bundle on X. E is said to be semistable if, for every reduction of structure group EP ⊂ E to a maximal parabolic subgroup P of G, we have degree EP (p) ≤ 0, where p is the Lie algebra of P and EP ...

  1. Spanning forests and the vector bundle Laplacian

    OpenAIRE

    Kenyon, Richard

    2011-01-01

    The classical matrix-tree theorem relates the determinant of the combinatorial Laplacian on a graph to the number of spanning trees. We generalize this result to Laplacians on one- and two-dimensional vector bundles, giving a combinatorial interpretation of their determinants in terms of so-called cycle rooted spanning forests (CRSFs). We construct natural measures on CRSFs for which the edges form a determinantal process. ¶ This theory gives a natural generalization of the spanning tre...

  2. Uncovering Ecosystem Service Bundles through Social Preferences

    Science.gov (United States)

    Martín-López, Berta; Iniesta-Arandia, Irene; García-Llorente, Marina; Palomo, Ignacio; Casado-Arzuaga, Izaskun; Amo, David García Del; Gómez-Baggethun, Erik; Oteros-Rozas, Elisa; Palacios-Agundez, Igone; Willaarts, Bárbara; González, José A.; Santos-Martín, Fernando; Onaindia, Miren; López-Santiago, Cesar; Montes, Carlos

    2012-01-01

    Ecosystem service assessments have increasingly been used to support environmental management policies, mainly based on biophysical and economic indicators. However, few studies have coped with the social-cultural dimension of ecosystem services, despite being considered a research priority. We examined how ecosystem service bundles and trade-offs emerge from diverging social preferences toward ecosystem services delivered by various types of ecosystems in Spain. We conducted 3,379 direct face-to-face questionnaires in eight different case study sites from 2007 to 2011. Overall, 90.5% of the sampled population recognized the ecosystem’s capacity to deliver services. Formal studies, environmental behavior, and gender variables influenced the probability of people recognizing the ecosystem’s capacity to provide services. The ecosystem services most frequently perceived by people were regulating services; of those, air purification held the greatest importance. However, statistical analysis showed that socio-cultural factors and the conservation management strategy of ecosystems (i.e., National Park, Natural Park, or a non-protected area) have an effect on social preferences toward ecosystem services. Ecosystem service trade-offs and bundles were identified by analyzing social preferences through multivariate analysis (redundancy analysis and hierarchical cluster analysis). We found a clear trade-off among provisioning services (and recreational hunting) versus regulating services and almost all cultural services. We identified three ecosystem service bundles associated with the conservation management strategy and the rural-urban gradient. We conclude that socio-cultural preferences toward ecosystem services can serve as a tool to identify relevant services for people, the factors underlying these social preferences, and emerging ecosystem service bundles and trade-offs. PMID:22720006

  3. Bundling harvester; Harvennuspuun automaattisen nippukorjausharvesterin kehittaeminen

    Energy Technology Data Exchange (ETDEWEB)

    Koponen, K [Eko-Log Oy, Kuopio (Finland)

    1997-12-01

    The starting point of the project was to design and construct, by taking the silvicultural point of view into account, a harvesting and processing system especially for energy-wood, containing manually driven bundling harvester, automating of the harvester, and automated loading. The equipment forms an ideal method for entrepreneur`s-line harvesting. The target is to apply the system also for owner`s-line harvesting. The profitability of the system promotes the utilisation of the system in both cases. The objectives of the project were: to construct a test equipment and prototypes for all the project stages, to carry out terrain and strain tests in order to examine the usability and durability, as well as the capacity of the machine, to test the applicability of the Eko-Log system in simultaneous harvesting of energy and pulp woods, and to start the marketing and manufacturing of the products. The basic problems of the construction of the bundling harvester have been solved using terrain-tests. The prototype machine has been shown to be operable. Loading of the bundles to form sufficiently economically transportable loads has been studied, and simultaneously, the branch-biomass has been tried to be utilised without loosing the profitability of transportation. The results have been promising, and will promote the profitable utilisation of wood-energy. (orig.)

  4. Experimental heat transfer in tube bundle

    International Nuclear Information System (INIS)

    Khattab, M.; Mariy, A.; Habib, M.

    1983-01-01

    Previous work has looked for the problem of heat transfer with flow parallel to rod bundle either by treating each rod individually as a separate channel or by treating the bundle as one unit. The present work will consider the existence of both the central and corner rods simultaneously inside the cluster itself under the same working conditions. The test section is geometrically similar to the fuel assembly of the Egyptian Research Reactor-1. The hydro-thermal performance of bundle having 16 - stainless steel tubes arranged in square array of 1.5 pitch to diameter ratio is investigated. Surface temperature and pressure distributions are determined. Average heat transfer coefficient for both central and corner tubes are correlated. Also, pressure drop and friction factor correlations are predicted. The maximum experimental range of the measured parameters are determined in the nonboiling region at 1400 Reynolds number and 3.64 W/cm 2 . It is found that the average heat transfer coefficient of the central tube is higher than that of the corner tube by 27%. Comparison with the previous work shows satisfactory agreement particularly with the circular tubes correlation - Dittus et al. - at 104 Reynolds number

  5. Characterization of a subunit of the outer dynein arm docking complex necessary for correct flagellar assembly in Leishmania donovani.

    Directory of Open Access Journals (Sweden)

    Simone Harder

    Full Text Available BACKGROUND: In order to proceed through their life cycle, Leishmania parasites switch between sandflies and mammals. The flagellated promastigote cells transmitted by the insect vector are phagocytized by macrophages within the mammalian host and convert into the amastigote stage, which possesses a rudimentary flagellum only. During an earlier proteomic study of the stage differentiation of the parasite we identified a component of the outer dynein arm docking complex, a structure of the flagellar axoneme. The 70 kDa subunit of the outer dynein arm docking complex consists of three subunits altogether and is essential for the assembly of the outer dynein arm onto the doublet microtubule of the flagella. According to the nomenclature of the well-studied Chlamydomonas reinhardtii complex we named the Leishmania protein LdDC2. METHODOLOGY/PRINCIPAL FINDINGS: This study features a characterization of the protein over the life cycle of the parasite. It is synthesized exclusively in the promastigote stage and localizes to the flagellum. Gene replacement mutants of lddc2 show reduced growth rates and diminished flagellar length. Additionally, the normally spindle-shaped promastigote parasites reveal a more spherical cell shape giving them an amastigote-like appearance. The mutants lose their motility and wiggle in place. Ultrastructural analyses reveal that the outer dynein arm is missing. Furthermore, expression of the amastigote-specific A2 gene family was detected in the deletion mutants in the absence of a stage conversion stimulus. In vitro infectivity is slightly increased in the mutant cell line compared to wild-type Leishmania donovani parasites. CONCLUSIONS/SIGNIFICANCE: Our results indicate that the correct assembly of the flagellum has a great influence on the investigated characteristics of Leishmania parasites. The lack of a single flagellar protein causes an aberrant morphology, impaired growth and altered infectiousness of the parasite.

  6. Independent evolution of neurotoxin and flagellar genetic loci in proteolytic Clostridium botulinum.

    Science.gov (United States)

    Carter, Andrew T; Paul, Catherine J; Mason, David R; Twine, Susan M; Alston, Mark J; Logan, Susan M; Austin, John W; Peck, Michael W

    2009-03-19

    Proteolytic Clostridium botulinum is the causative agent of botulism, a severe neuroparalytic illness. Given the severity of botulism, surprisingly little is known of the population structure, biology, phylogeny or evolution of C. botulinum. The recent determination of the genome sequence of C. botulinum has allowed comparative genomic indexing using a DNA microarray. Whole genome microarray analysis revealed that 63% of the coding sequences (CDSs) present in reference strain ATCC 3502 were common to all 61 widely-representative strains of proteolytic C. botulinum and the closely related C. sporogenes tested. This indicates a relatively stable genome. There was, however, evidence for recombination and genetic exchange, in particular within the neurotoxin gene and cluster (including transfer of neurotoxin genes to C. sporogenes), and the flagellar glycosylation island (FGI). These two loci appear to have evolved independently from each other, and from the remainder of the genetic complement. A number of strains were atypical; for example, while 10 out of 14 strains that formed type A1 toxin gave almost identical profiles in whole genome, neurotoxin cluster and FGI analyses, the other four strains showed divergent properties. Furthermore, a new neurotoxin sub-type (A5) has been discovered in strains from heroin-associated wound botulism cases. For the first time, differences in glycosylation profiles of the flagella could be linked to differences in the gene content of the FGI. Proteolytic C. botulinum has a stable genome backbone containing specific regions of genetic heterogeneity. These include the neurotoxin gene cluster and the FGI, each having evolved independently of each other and the remainder of the genetic complement. Analysis of these genetic components provides a high degree of discrimination of strains of proteolytic C. botulinum, and is suitable for clinical and forensic investigations of botulism outbreaks.

  7. Independent evolution of neurotoxin and flagellar genetic loci in proteolytic Clostridium botulinum

    Directory of Open Access Journals (Sweden)

    Twine Susan M

    2009-03-01

    Full Text Available Abstract Background Proteolytic Clostridium botulinum is the causative agent of botulism, a severe neuroparalytic illness. Given the severity of botulism, surprisingly little is known of the population structure, biology, phylogeny or evolution of C. botulinum. The recent determination of the genome sequence of C. botulinum has allowed comparative genomic indexing using a DNA microarray. Results Whole genome microarray analysis revealed that 63% of the coding sequences (CDSs present in reference strain ATCC 3502 were common to all 61 widely-representative strains of proteolytic C. botulinum and the closely related C. sporogenes tested. This indicates a relatively stable genome. There was, however, evidence for recombination and genetic exchange, in particular within the neurotoxin gene and cluster (including transfer of neurotoxin genes to C. sporogenes, and the flagellar glycosylation island (FGI. These two loci appear to have evolved independently from each other, and from the remainder of the genetic complement. A number of strains were atypical; for example, while 10 out of 14 strains that formed type A1 toxin gave almost identical profiles in whole genome, neurotoxin cluster and FGI analyses, the other four strains showed divergent properties. Furthermore, a new neurotoxin sub-type (A5 has been discovered in strains from heroin-associated wound botulism cases. For the first time, differences in glycosylation profiles of the flagella could be linked to differences in the gene content of the FGI. Conclusion Proteolytic C. botulinum has a stable genome backbone containing specific regions of genetic heterogeneity. These include the neurotoxin gene cluster and the FGI, each having evolved independently of each other and the remainder of the genetic complement. Analysis of these genetic components provides a high degree of discrimination of strains of proteolytic C. botulinum, and is suitable for clinical and forensic investigations of botulism

  8. Study of fuel bundle geometry on inter subchannel flow in a 19 pin wire wrapped bundle

    International Nuclear Information System (INIS)

    Naveen Raj, M.; Velusamy, D.K.

    2015-01-01

    In typical sodium cooled fast reactor (SFR) fuel pin bundle, gap between the pins is maintained by helically wound wire wrap around each pin. The presence of wire induces large inter-subchannel transverse flow, eventually promoting mixing and heat transfer. The magnitude of the transverse flow is highly dependent on the various pin-bundle dimensions. Appropriate modeling of these transverse flows in subchannel codes is necessary to predict realistic temperature distribution in pin bundle. Hence, detailed parametric study of transverse flow on pin-bundle geometric parameters has been conducted. The parameters taken for the present study are pin diameter, wire diameter, helical wire pitch and edge gap. Towards this 3-D computational fluid dynamic analysis on a structured mesh of 19 pin bundle is carried out using k-epsilon turbulence model. Periodic oscillations along the primacy flow direction were found in subchannel transverse flow and peripheral pin clad temperatures with periodicity over one pitch length. Based on parametric studies, correlations for transverse flow in central subchannels are proposed. (author)

  9. Bundled payment fails to gain a foothold In California: the experience of the IHA bundled payment demonstration.

    Science.gov (United States)

    Ridgely, M Susan; de Vries, David; Bozic, Kevin J; Hussey, Peter S

    2014-08-01

    To determine whether bundled payment could be an effective payment model for California, the Integrated Healthcare Association convened a group of stakeholders (health plans, hospitals, ambulatory surgery centers, physician organizations, and vendors) to develop, through a consensus process, the methods and means of implementing bundled payment. In spite of a high level of enthusiasm and effort, the pilot did not succeed in its goal to implement bundled payment for orthopedic procedures across multiple payers and hospital-physician partners. An evaluation of the pilot documented a number of barriers, such as administrative burden, state regulatory uncertainty, and disagreements about bundle definition and assumption of risk. Ultimately, few contracts were signed, which resulted in insufficient volume to test hypotheses about the impact of bundled payment on quality and costs. Although bundled payment failed to gain a foothold in California, the evaluation provides lessons for future bundled payment initiatives. Project HOPE—The People-to-People Health Foundation, Inc.

  10. Nanotube bundle oscillators: Carbon and boron nitride nanostructures

    International Nuclear Information System (INIS)

    Thamwattana, Ngamta; Hill, James M.

    2009-01-01

    In this paper, we investigate the oscillation of a fullerene that is moving within the centre of a bundle of nanotubes. In particular, certain fullerene-nanotube bundle oscillators, namely C 60 -carbon nanotube bundle, C 60 -boron nitride nanotube bundle, B 36 N 36 -carbon nanotube bundle and B 36 N 36 -boron nitride nanotube bundle are studied using the Lennard-Jones potential and the continuum approach which assumes a uniform distribution of atoms on the surface of each molecule. We address issues regarding the maximal suction energies of the fullerenes which lead to the generation of the maximum oscillation frequency. Since bundles are also found to comprise double-walled nanotubes, this paper also examines the oscillation of a fullerene inside a double-walled nanotube bundle. Our results show that the frequencies obtained for the oscillation within double-walled nanotube bundles are slightly higher compared to those of single-walled nanotube bundle oscillators. Our primary purpose here is to extend a number of established results for carbon to the boron nitride nanostructures.

  11. Dimensional measurement of fresh fuel bundle for CANDU reactor

    International Nuclear Information System (INIS)

    Jo, Chang Keun; Cho, Moon Sung; Suk, Ho Chun; Koo, Dae Seo; Jun, Ji Su; Jung, Jong Yeob

    2005-01-01

    This report describes the results of the dimensional measurement of fresh fuel bundles for the CANDU reactor in order to estimate the integrity of fuel bundle in two-phase flow in the CANDU-6 fuel channel. The dimensional measurements of fuel bundles are performed by using the 'CANDU Fuel In-Bay Inspection and Dimensional Measurement System', which was developed by this project. The dimensional measurements are done from February 2004 to March 2004 in the CANDU fuel storage of KNFC for the 36 fresh fuel bundles, which are produced by KNFC and are waiting for the delivery to the Wolsong-3 plant. The detail items of dimensional measurements are included fuel rod and bearing pad profiles of the outer ring in fuel bundle, diameter of fuel bundle, bowing of fuel bundle, fuel rod length, and surface profile of end plate profile. The measurement data will be compared with those of the post-irradiated bundles cooled in Wolsong-3 NPP spent fuel pool by using the same bundles and In-Bay Measurement System. So, this analysis of data will be applied for the evaluation of fuel bundle integrity in two-phase flow of the CANDU-6 fuel channel

  12. Stability of Picard bundle over moduli space of stable vector bundles ...

    Indian Academy of Sciences (India)

    Springer Verlag Heidelberg #4 2048 1996 Dec 15 10:16:45

    Since the morphism ϕ is given by the universal property of the moduli space, the pullback of the universal bundle E on X × M to X × P by the map idX × ϕ is isomorphic (up to a twist by a line bundle coming from P) to ˜E. In other words, there is an integer k such that. 0 −→ (idX × ϕ)∗E −→ W ⊠ OP (k) −→ Ox×P (k + 1) −→ 0.

  13. Bacterial prostatitis.

    Science.gov (United States)

    Gill, Bradley C; Shoskes, Daniel A

    2016-02-01

    The review provides the infectious disease community with a urologic perspective on bacterial prostatitis. Specifically, the article briefly reviews the categorization of prostatitis by type and provides a distillation of new findings published on bacterial prostatitis over the past year. It also highlights key points from the established literature. Cross-sectional prostate imaging is becoming more common and may lead to more incidental diagnoses of acute bacterial prostatitis. As drug resistance remains problematic in this condition, the reemergence of older antibiotics such as fosfomycin, has proven beneficial. With regard to chronic bacterial prostatitis, no clear clinical risk factors emerged in a large epidemiological study. However, bacterial biofilm formation has been associated with more severe cases. Surgery has a limited role in bacterial prostatitis and should be reserved for draining of a prostatic abscess or the removal of infected prostatic stones. Prostatitis remains a common and bothersome clinical condition. Antibiotic therapy remains the basis of treatment for both acute and chronic bacterial prostatitis. Further research into improving prostatitis treatment is indicated.

  14. Influence of Bundle Diameter and Attachment Point on Kinematic Behavior in Double Bundle Anterior Cruciate Ligament Reconstruction Using Computational Model

    Directory of Open Access Journals (Sweden)

    Oh Soo Kwon

    2014-01-01

    Full Text Available A protocol to choose the graft diameter attachment point of each bundle has not yet been determined since they are usually dependent on a surgeon’s preference. Therefore, the influence of bundle diameters and attachment points on the kinematics of the knee joint needs to be quantitatively analyzed. A three-dimensional knee model was reconstructed with computed tomography images of a 26-year-old man. Based on the model, models of double bundle anterior cruciate ligament (ACL reconstruction were developed. The anterior tibial translations for the anterior drawer test and the internal tibial rotation for the pivot shift test were investigated according to variation of bundle diameters and attachment points. For the model in this study, the knee kinematics after the double bundle ACL reconstruction were dependent on the attachment point and not much influenced by the bundle diameter although larger sized anterior-medial bundles provided increased stability in the knee joint. Therefore, in the clinical setting, the bundle attachment point needs to be considered prior to the bundle diameter, and the current selection method of graft diameters for both bundles appears justified.

  15. A Tannakian approach to dimensional reduction of principal bundles

    Science.gov (United States)

    Álvarez-Cónsul, Luis; Biswas, Indranil; García-Prada, Oscar

    2017-08-01

    Let P be a parabolic subgroup of a connected simply connected complex semisimple Lie group G. Given a compact Kähler manifold X, the dimensional reduction of G-equivariant holomorphic vector bundles over X × G / P was carried out in Álvarez-Cónsul and García-Prada (2003). This raises the question of dimensional reduction of holomorphic principal bundles over X × G / P. The method of Álvarez-Cónsul and García-Prada (2003) is special to vector bundles; it does not generalize to principal bundles. In this paper, we adapt to equivariant principal bundles the Tannakian approach of Nori, to describe the dimensional reduction of G-equivariant principal bundles over X × G / P, and to establish a Hitchin-Kobayashi type correspondence. In order to be able to apply the Tannakian theory, we need to assume that X is a complex projective manifold.

  16. Analytical prediction of turbulent friction factor for a rod bundle

    International Nuclear Information System (INIS)

    Bae, Jun Ho; Park, Joo Hwan

    2011-01-01

    An analytical calculation has been performed to predict the turbulent friction factor in a rod bundle. For each subchannel constituting a rod bundle, the geometry parameters are analytically derived by integrating the law of the wall over each subchannel with the consideration of a local shear stress distribution. The correlation equations for a local shear stress distribution are supplied from a numerical simulation for each subchannel. The explicit effect of a subchannel shape on the geometry parameter and the friction factor is reported. The friction factor of a corner subchannel converges to a constant value, while the friction factor of a central subchannel steadily increases with a rod distance ratio. The analysis for a rod bundle shows that the friction factor of a rod bundle is largely affected by the characteristics of each subchannel constituting a rod bundle. The present analytic calculations well predict the experimental results from the literature with rod bundles in circular, hexagonal, and square channels.

  17. Matrix remodeling between cells and cellular interactions with collagen bundle

    Science.gov (United States)

    Kim, Jihan; Sun, Bo

    When cells are surrounded by complex environment, they continuously probe and interact with it by applying cellular traction forces. As cells apply traction forces, they can sense rigidity of their local environment and remodel the matrix microstructure simultaneously. Previous study shows that single human carcinoma cell (MDA-MB-231) remodeled its surrounding extracellular matrix (ECM) and the matrix remodeling was reversible. In this study we examined the matrix microstructure between cells and cellular interaction between them using quantitative confocal microscopy. The result shows that the matrix microstructure is the most significantly remodeled between cells consisting of aligned, and densified collagen fibers (collagen bundle)., the result shows that collagen bundle is irreversible and significantly change micromechanics of ECM around the bundle. We further examined cellular interaction with collagen bundle by analyzing dynamics of actin and talin formation along with the direction of bundle. Lastly, we analyzed dynamics of cellular protrusion and migrating direction of cells along the bundle.

  18. MODULAR BUNDLE ADJUSTMENT FOR PHOTOGRAMMETRIC COMPUTATIONS

    Directory of Open Access Journals (Sweden)

    N. Börlin

    2018-05-01

    Full Text Available In this paper we investigate how the residuals in bundle adjustment can be split into a composition of simple functions. According to the chain rule, the Jacobian (linearisation of the residual can be formed as a product of the Jacobians of the individual steps. When implemented, this enables a modularisation of the computation of the bundle adjustment residuals and Jacobians where each component has limited responsibility. This enables simple replacement of components to e.g. implement different projection or rotation models by exchanging a module. The technique has previously been used to implement bundle adjustment in the open-source package DBAT (Börlin and Grussenmeyer, 2013 based on the Photogrammetric and Computer Vision interpretations of Brown (1971 lens distortion model. In this paper, we applied the technique to investigate how affine distortions can be used to model the projection of a tilt-shift lens. Two extended distortion models were implemented to test the hypothesis that the ordering of the affine and lens distortion steps can be changed to reduce the size of the residuals of a tilt-shift lens calibration. Results on synthetic data confirm that the ordering of the affine and lens distortion steps matter and is detectable by DBAT. However, when applied to a real camera calibration data set of a tilt-shift lens, no difference between the extended models was seen. This suggests that the tested hypothesis is false and that other effects need to be modelled to better explain the projection. The relatively low implementation effort that was needed to generate the models suggest that the technique can be used to investigate other novel projection models in photogrammetry, including modelling changes in the 3D geometry to better understand the tilt-shift lens.

  19. Historical dynamics in ecosystem service bundles.

    Science.gov (United States)

    Renard, Delphine; Rhemtulla, Jeanine M; Bennett, Elena M

    2015-10-27

    Managing multiple ecosystem services (ES), including addressing trade-offs between services and preventing ecological surprises, is among the most pressing areas for sustainability research. These challenges require ES research to go beyond the currently common approach of snapshot studies limited to one or two services at a single point in time. We used a spatiotemporal approach to examine changes in nine ES and their relationships from 1971 to 2006 across 131 municipalities in a mixed-use landscape in Quebec, Canada. We show how an approach that incorporates time and space can improve our understanding of ES dynamics. We found an increase in the provision of most services through time; however, provision of ES was not uniformly enhanced at all locations. Instead, each municipality specialized in providing a bundle (set of positively correlated ES) dominated by just a few services. The trajectory of bundle formation was related to changes in agricultural policy and global trends; local biophysical and socioeconomic characteristics explained the bundles' increasing spatial clustering. Relationships between services varied through time, with some provisioning and cultural services shifting from a trade-off or no relationship in 1971 to an apparent synergistic relationship by 2006. By implementing a spatiotemporal perspective on multiple services, we provide clear evidence of the dynamic nature of ES interactions and contribute to identifying processes and drivers behind these changing relationships. Our study raises questions about using snapshots of ES provision at a single point in time to build our understanding of ES relationships in complex and dynamic social-ecological systems.

  20. Hydrodynamic behavior of a bare rod bundle

    International Nuclear Information System (INIS)

    Bartzis, J.G.; Todreas, N.E.

    1977-06-01

    The temperature distribution within the rod bundle of a nuclear reactor is of major importance in nuclear reactor design. However temperature information presupposes knowledge of the hydrodynamic behavior of the coolant which is the most difficult part of the problem due to complexity of the turbulence phenomena. In the present work a 2-equation turbulence model--a strong candidate for analyzing actual three dimensional turbulent flows--has been used to predict fully developed flow of infinite bare rod bundle of various aspect ratios (P/D). The model has been modified to take into account anisotropic effects of eddy viscosity. Secondary flow calculations have been also performed although the model seems to be too rough to predict the secondary flow correctly. Heat transfer calculations have been performed to confirm the importance of anisotropic viscosity in temperature predictions. All numerical calculations for flow and heat have been performed by two computer codes based on the TEACH code. Experimental measurements of the distribution of axial velocity, turbulent axial velocity, turbulent kinetic energy and radial Reynolds stresses were performed in the developing and fully developed regions. A 2-channel Laser Doppler Anemometer working on the Reference mode with forward scattering was used to perform the measurements in a simulated interior subchannel of a triangular rod array with P/D = 1.124. Comparisons between the analytical results and the results of this experiment as well as other experimental data in rod bundle array available in literature are presented. The predictions are in good agreement with the results for the high Reynolds numbers

  1. Global properties of systems quantized via bundles

    International Nuclear Information System (INIS)

    Doebner, H.D.; Werth, J.E.

    1978-03-01

    Take a smooth manifold M and a Lie algebra action (g-ation) theta on M as the geometrical arena of a physical system moving on M with momenta given by theta. It is proposed to quantize the system with a Mackey-like method via the associated vector bundle xisub(rho) of a principal bundle xi=(P,π,M,H) with model dependent structure group H and with g-action phi on P lifted from theta on M. This (quantization) bundle xisub(rho) gives the Hilbert space equal to L 2 (xisub(rho),ω) of the system as the linear space of sections in xisub(rho) being square integrable with respect to a volume form ω on M; the usual position operators are obtained; phi leads to a vector field representation D(phisub(rho),theta) of g in an hence Hilbert space to momentum operators. So Hilbert space carries the quantum kinematics. In this quantuzation the physically important connection between geometrical properties of the system, e.g. quasi-completeness of theta and G-maximality of phisub(rho), and global properties of its quantized kinematics, e.g. skew-adjointness of the momenta and integrability of D(phisub(rho), theta) can easily be studied. The relation to Nelson's construction of a skew-adjoint non-integrable Lie algebra representation and to Palais' local G-action is discussed. Finally the results are applied to actions induced by coverings as examples of non-maximal phisub(rho) on Esub(rho) lifted from maximal theta on M which lead to direct consequences for the corresponding quantum kinematics

  2. Modular Bundle Adjustment for Photogrammetric Computations

    Science.gov (United States)

    Börlin, N.; Murtiyoso, A.; Grussenmeyer, P.; Menna, F.; Nocerino, E.

    2018-05-01

    In this paper we investigate how the residuals in bundle adjustment can be split into a composition of simple functions. According to the chain rule, the Jacobian (linearisation) of the residual can be formed as a product of the Jacobians of the individual steps. When implemented, this enables a modularisation of the computation of the bundle adjustment residuals and Jacobians where each component has limited responsibility. This enables simple replacement of components to e.g. implement different projection or rotation models by exchanging a module. The technique has previously been used to implement bundle adjustment in the open-source package DBAT (Börlin and Grussenmeyer, 2013) based on the Photogrammetric and Computer Vision interpretations of Brown (1971) lens distortion model. In this paper, we applied the technique to investigate how affine distortions can be used to model the projection of a tilt-shift lens. Two extended distortion models were implemented to test the hypothesis that the ordering of the affine and lens distortion steps can be changed to reduce the size of the residuals of a tilt-shift lens calibration. Results on synthetic data confirm that the ordering of the affine and lens distortion steps matter and is detectable by DBAT. However, when applied to a real camera calibration data set of a tilt-shift lens, no difference between the extended models was seen. This suggests that the tested hypothesis is false and that other effects need to be modelled to better explain the projection. The relatively low implementation effort that was needed to generate the models suggest that the technique can be used to investigate other novel projection models in photogrammetry, including modelling changes in the 3D geometry to better understand the tilt-shift lens.

  3. Bacterial Vaginosis

    Science.gov (United States)

    ... Archive STDs Home Page Bacterial Vaginosis (BV) Chlamydia Gonorrhea Genital Herpes Hepatitis HIV/AIDS & STDs Human Papillomavirus ( ... of getting other STDs, such as chlamydia and gonorrhea . These bacteria can sometimes cause pelvic inflammatory disease ( ...

  4. A Hodge dual for soldered bundles

    International Nuclear Information System (INIS)

    Lucas, Tiago Gribl; Pereira, J G

    2009-01-01

    In order to account for all possible contractions allowed by the presence of the solder form, a generalized Hodge dual is defined for the case of soldered bundles. Although for curvature the generalized dual coincides with the usual one, for torsion it gives a completely new dual definition. Starting from the standard form of a gauge Lagrangian for the translation group, the generalized Hodge dual yields precisely the Lagrangian of the teleparallel equivalent of general relativity, and consequently also the Einstein-Hilbert Lagrangian of general relativity

  5. Bundling Products and Services Through Modularization Strategies

    DEFF Research Database (Denmark)

    Bask, Anu; Hsuan, Juliana; Rajahonka, Mervi

    2012-01-01

    Modularity has been recognized as a powerful tool in improving the efficiency and management of product design and manufacturing. However, the integrated view on covering both, product and service modularity for product-service systems (PSS), is under researched. Therefore, in this paper our...... objective is to contribute to the PSS modularity. Thus, we describe configurations of PSSs and the bundling of products and services through modularization strategies. So far there have not been tools to analyze and determine the correct combinations of degrees of product and service modularities....

  6. SEU43 fuel bundles in CANDU 600

    International Nuclear Information System (INIS)

    Catana, Alexandru; Prodea, Iosif; Danila, Nicolae; Prisecaru, Ilie; Dupleac, Daniel

    2008-01-01

    Cernavoda Unit 1 and Unit 2 are pressure tube 650 MWe nuclear stations moderated and cooled with heavy water, of Canada design, located in Romania. Fuelling is on-power and the plant is currently fuelled with natural uranium dioxide. Fuel is encapsulated in a 37 fuel rod assembly having a specific standard geometry (STD37). In order to reduce fuel cycle costs programs were initiated in Canada, South Korea and at SCN Pitesti, Romania for design and build of a new, improved geometry fuel bundle and some fuel compositions. Among fuel compositions, which are considered, is the slightly enriched uranium (SEU) fuel (0.96 w% U-235) with an associated burn-up increase from ∼7900 MWd/tU up to ∼15000 MWd/tU. Neutron analysis showed that the Canadian-Korean fuel bundle geometry with 43 rods called SEU (SEU43) can be used in already operated reactors. A new fuel bundle resulted. Extended, comprehensive analysis must be conducted in order to assess the TH behavior of SEU43 besides the neutron, mechanical (drag force, etc) analyses. In this paper, using the sub-channel approach, main thermal-hydraulic parameters were analyzed: pressure drop; fuel, sheath and coolant temperatures; coolant density; critical heat flux. Some significant differences versus standard fuel are outlined in the paper and some conclusions are drawn. While, by using this new fuel, there are many benefits to be attained like: fuel costs reduction, spent fuel waste minimization, increase in competitiveness of nuclear power generation against other sources of generation, etc., the safety margins must be, at least, conserved. The introduction of a new fuel bundle type, different in geometry and fuel composition, requires a detailed preparation, a testing program and a series of neutron and thermal-hydraulic analysis. The results reported by this paper is part of this effort. The feasibility to increase the enrichment from 0.71% U-235 (NU) to 0.96% U-235, with an estimated burn-up increase up to 14000 MWd

  7. Vector bundles on complex projective spaces

    CERN Document Server

    Okonek, Christian; Spindler, Heinz

    1980-01-01

    This expository treatment is based on a survey given by one of the authors at the Séminaire Bourbaki in November 1978 and on a subsequent course held at the University of Göttingen. It is intended to serve as an introduction to the topical question of classification of holomorphic vector bundles on complex projective spaces, and can easily be read by students with a basic knowledge of analytic or algebraic geometry. Short supplementary sections describe more advanced topics, further results, and unsolved problems.

  8. Differential geometry bundles, connections, metrics and curvature

    CERN Document Server

    Taubes, Clifford Henry

    2011-01-01

    Bundles, connections, metrics and curvature are the 'lingua franca' of modern differential geometry and theoretical physics. This book will supply a graduate student in mathematics or theoretical physics with the fundamentals of these objects. Many of the tools used in differential topology are introduced and the basic results about differentiable manifolds, smooth maps, differential forms, vector fields, Lie groups, and Grassmanians are all presented here. Other material covered includes the basic theorems about geodesics and Jacobi fields, the classification theorem for flat connections, the

  9. Assembly mechanism for nuclear fuel bundles

    International Nuclear Information System (INIS)

    Long, J.W.; Flora, B.S.; Ford, K.L.

    1980-01-01

    The invention relates to a nuclear power reactor fuel bundle of the type wherein several rods are mounted in parallel array between two tie plates which secure the fuel rods in place and are maintained in assembled position by means of a number of tie rods secured to both of the end plates. Improved apparatus is provided for attaching the tie rods to the upper tie plate by the use of locking lugs fixed to rotatable sleeves which engage the upper tie plate. (auth)

  10. Deformation quantization with separation of variables of an endomorphism bundle

    Science.gov (United States)

    Karabegov, Alexander

    2014-01-01

    Given a holomorphic Hermitian vector bundle E and a star-product with separation of variables on a pseudo-Kähler manifold, we construct a star product on the sections of the endomorphism bundle of the dual bundle E∗ which also has the appropriately generalized property of separation of variables. For this star product we prove a generalization of Gammelgaard's graph-theoretic formula.

  11. Relativistic rotators: a quantum mechanical de Sitter bundle

    International Nuclear Information System (INIS)

    Boehm, A.

    1976-02-01

    If de Sitter fiber bundle over space time is the classical picture of hadrons then for a quantum mechanical description one has to generalize the concept of a principal fiber bundle to a bundle that contains the representation of the group of motion. This idea is related to the relativistic rotator model, and the radius of the de Sitter fiber is determined from the experimental hadron spectrum

  12. Crossed Module Bundle Gerbes; Classification, String Group and Differential Geometry

    OpenAIRE

    Jurco, Branislav

    2005-01-01

    We discuss nonabelian bundle gerbes and their differential geometry using simplicial methods. Associated to any crossed module there is a simplicial group NC, the nerve of the 1-category defined by the crossed module and its geometric realization |NC|. Equivalence classes of principal bundles with structure group |NC| are shown to be one-to-one with stable equivalence classes of what we call crossed module gerbes bundle gerbes. We can also associate to a crossed module a 2-category C'. Then t...

  13. Analytic convergence of harmonic metrics for parabolic Higgs bundles

    Science.gov (United States)

    Kim, Semin; Wilkin, Graeme

    2018-04-01

    In this paper we investigate the moduli space of parabolic Higgs bundles over a punctured Riemann surface with varying weights at the punctures. We show that the harmonic metric depends analytically on the weights and the stable Higgs bundle. This gives a Higgs bundle generalisation of a theorem of McOwen on the existence of hyperbolic cone metrics on a punctured surface within a given conformal class, and a generalisation of a theorem of Judge on the analytic parametrisation of these metrics.

  14. Early Results of Anatomic Double Bundle Anterior Cruciate Ligament Reconstruction

    OpenAIRE

    Demet Pepele

    2014-01-01

    Aim: The goal in anterior cruciate ligament reconstruction (ACLR) is to restore the normal anatomic structure and function of the knee. In the significant proportion of patients after the traditional single-bundle ACLR, complaints of instability still continue. Anatomic double bundle ACLR may provide normal kinematics in knees, much closer to the natural anatomy. The aim of this study is to clinically assess the early outcomes of our anatomical double bundle ACLR. Material and Method: In our ...

  15. Heat Transfer Analysis in Wire Bundles for Aerospace Vehicles

    Science.gov (United States)

    Rickman, S. L.; Iamello, C. J.

    2016-01-01

    Design of wiring for aerospace vehicles relies on an understanding of "ampacity" which refers to the current carrying capacity of wires, either, individually or in wire bundles. Designers rely on standards to derate allowable current flow to prevent exceedance of wire temperature limits due to resistive heat dissipation within the wires or wire bundles. These standards often add considerable margin and are based on empirical data. Commercial providers are taking an aggressive approach to wire sizing which challenges the conventional wisdom of the established standards. Thermal modelling of wire bundles may offer significant mass reduction in a system if the technique can be generalized to produce reliable temperature predictions for arbitrary bundle configurations. Thermal analysis has been applied to the problem of wire bundles wherein any or all of the wires within the bundle may carry current. Wire bundles present analytical challenges because the heat transfer path from conductors internal to the bundle is tortuous, relying on internal radiation and thermal interface conductance to move the heat from within the bundle to the external jacket where it can be carried away by convective and radiative heat transfer. The problem is further complicated by the dependence of wire electrical resistivity on temperature. Reduced heat transfer out of the bundle leads to higher conductor temperatures and, hence, increased resistive heat dissipation. Development of a generalized wire bundle thermal model is presented and compared with test data. The steady state heat balance for a single wire is derived and extended to the bundle configuration. The generalized model includes the effects of temperature varying resistance, internal radiation and thermal interface conductance, external radiation and temperature varying convective relief from the free surface. The sensitivity of the response to uncertainties in key model parameters is explored using Monte Carlo analysis.

  16. Local load-sharing fiber bundle model in higher dimensions.

    Science.gov (United States)

    Sinha, Santanu; Kjellstadli, Jonas T; Hansen, Alex

    2015-08-01

    We consider the local load-sharing fiber bundle model in one to five dimensions. Depending on the breaking threshold distribution of the fibers, there is a transition where the fracture process becomes localized. In the localized phase, the model behaves as the invasion percolation model. The difference between the local load-sharing fiber bundle model and the equal load-sharing fiber bundle model vanishes with increasing dimensionality with the characteristics of a power law.

  17. Warps, grids and curvature in triple vector bundles

    Science.gov (United States)

    Flari, Magdalini K.; Mackenzie, Kirill

    2018-06-01

    A triple vector bundle is a cube of vector bundle structures which commute in the (strict) categorical sense. A grid in a triple vector bundle is a collection of sections of each bundle structure with certain linearity properties. A grid provides two routes around each face of the triple vector bundle, and six routes from the base manifold to the total manifold; the warps measure the lack of commutativity of these routes. In this paper we first prove that the sum of the warps in a triple vector bundle is zero. The proof we give is intrinsic and, we believe, clearer than the proof using decompositions given earlier by one of us. We apply this result to the triple tangent bundle T^3M of a manifold and deduce (as earlier) the Jacobi identity. We further apply the result to the triple vector bundle T^2A for a vector bundle A using a connection in A to define a grid in T^2A . In this case the curvature emerges from the warp theorem.

  18. Experimental and numerical investigations of BWR fuel bundle inlet flow

    International Nuclear Information System (INIS)

    Hoashi, E; Morooka, S; Ishitori, T; Komita, H; Endo, T; Honda, H; Yamamoto, T; Kato, T; Kawamura, S

    2009-01-01

    We have been studying the mechanism of the flow pattern near the fuel bundle inlet of BWR using both flow visualization test and computational fluid dynamics (CFD) simulation. In the visualization test, both single- and multi-bundle test sections were used. The former test section includes only a corner orifice facing two support beams and the latter simulates 16 bundles surrounded by four beams. An observation window is set on the side of the walls imitating the support beams upstream of the orifices in both test sections. In the CFD simulation, as well as the visualization test, the single-bundle model is composed of one bundle with a corner orifice and the multi-bundle model is a 1/4 cut of the test section that includes 4 bundles with the following four orifices: a corner orifice facing the corner of the two neighboring support beams, a center orifice at the opposite side from the corner orifice, and two side orifices. Twin-vortices were observed just upstream of the corner orifice in the multi-bundle test as well as the single-bundle test. A single-vortex and a vortex filament were observed at the side orifice inlet and no vortex was observed at the center orifice. These flow patterns were also predicted in the CFD simulation using Reynolds Stress Model as a turbulent model and the results were in good agreement with the test results mentioned above. (author)

  19. Enthalpy and void distributions in subchannels of PHWR fuel bundles

    Energy Technology Data Exchange (ETDEWEB)

    Park, J W; Choi, H; Rhee, B W [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1999-12-31

    Two different types of the CANDU fuel bundles have been modeled for the ASSERT-IV code subchannel analysis. From calculated values of mixture enthalpy and void fraction distribution in the fuel bundles, it is found that net buoyancy effect is pronounced in the central region of the DUPIC fuel bundle when compared with the standard CANDU fuel bundle. It is also found that the central region of the DUPIC fuel bundle can be cooled more efficiently than that of the standard fuel bundle. From the calculated mixture enthalpy distribution at the exit of the fuel channel, it is found that the mixture enthalpy and void fraction can be highest in the peripheral region of the DUPIC fuel bundle. On the other hand, the enthalpy and the void fraction were found to be highest in the central region of the standard CANDU fuel bundle at the exit of the fuel channel. This study shows that the subchannel analysis is very useful in assessing thermal behavior of the fuel bundle that could be used in CANDU reactors. 10 refs., 4 figs., 2 tabs. (Author)

  20. Enthalpy and void distributions in subchannels of PHWR fuel bundles

    Energy Technology Data Exchange (ETDEWEB)

    Park, J. W.; Choi, H.; Rhee, B. W. [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1998-12-31

    Two different types of the CANDU fuel bundles have been modeled for the ASSERT-IV code subchannel analysis. From calculated values of mixture enthalpy and void fraction distribution in the fuel bundles, it is found that net buoyancy effect is pronounced in the central region of the DUPIC fuel bundle when compared with the standard CANDU fuel bundle. It is also found that the central region of the DUPIC fuel bundle can be cooled more efficiently than that of the standard fuel bundle. From the calculated mixture enthalpy distribution at the exit of the fuel channel, it is found that the mixture enthalpy and void fraction can be highest in the peripheral region of the DUPIC fuel bundle. On the other hand, the enthalpy and the void fraction were found to be highest in the central region of the standard CANDU fuel bundle at the exit of the fuel channel. This study shows that the subchannel analysis is very useful in assessing thermal behavior of the fuel bundle that could be used in CANDU reactors. 10 refs., 4 figs., 2 tabs. (Author)

  1. Annular burnout data from rod-bundle experiments

    International Nuclear Information System (INIS)

    Yoder, G.L.; Morris, D.G.; Mullins, C.B.

    1983-01-01

    Burnout data for annular flow in a rod bundle are presented for both transient and steady-state conditions. Tests were performed at the Oak Ridge National Laboratory in the Thermal Hydraulic Test Facility (THTF), a pressurized-water loop containing an electrically heated 64-rod bundle. The bundle configuration is typical of later generation pressurized-water reactors with 17 x 17 fuel arrays. Both axial and radial power profiles are flat. All experiments were carried out in upflow with subcooled inlet conditions, insuring accurate flow measurement. Conditions within the bundle were typical of those which could be encountered during a nuclear reactor loss-of-coolant accident

  2. The differential geometry of higher order jets and tangent bundles

    International Nuclear Information System (INIS)

    De Leon, M.; Rodrigues, P.R.

    1985-01-01

    This chapter is devoted to the study of basic geometrical notions required for the development of the main object of the text. Some facts about Jet theory are reviewed. A particular case of Jet manifolds is considered: the tangent bundle of higher order. It is shown that this jet bundle possesses in a canonical way a certain kind of geometric structure, the so called almost tangent structure of higher order, and which is a generalization of the almost tangent geometry of the tangent bundle. Another important fact examined is the extension of the notion of 'spray' to higher order tangent bundles. (Auth.)

  3. Restriction Theorem for Principal bundles in Arbitrary Characteristic

    DEFF Research Database (Denmark)

    Gurjar, Sudarshan

    2015-01-01

    The aim of this paper is to prove two basic restriction theorem for principal bundles on smooth projective varieties in arbitrary characteristic generalizing the analogues theorems of Mehta-Ramanathan for vector bundles. More precisely, let G be a reductive algebraic group over an algebraically...... closed field k and let X be a smooth, projective variety over k together with a very ample line bundle O(1). The main result of the paper is that if E is a semistable (resp. stable) principal G-bundle on X w.r.t O(1), then the restriction of E to a general, high multi-degree, complete-intersection curve...

  4. The flagellar master operon flhDC is a pleiotropic regulator involved in motility and virulence of the fish pathogen Yersinia ruckeri

    Science.gov (United States)

    Aims: To investigate the function of the master flagellar operon flhDC in the fish pathogen Yersinia ruckeri and compare the effect of flhD mutation to a naturally occurring mutation causing loss-of-motility in emergent biotype 2 (BT2) strains. Methods and Results: In this study isogenic Y. ruckeri ...

  5. Ultrastructure of the harmful unarmored dinoflagellate Cochlodinium polykrikoides (Dinophyceae) with reference to the apical groove and flagellar apparatus

    DEFF Research Database (Denmark)

    Iwataki, Mitsunori; Hansen, Gert; Moestrup, Øjvind

    2010-01-01

    The external and internal ultrastructure of the harmful unarmored dinoflagellate Cochlodinium polykrikoides Margalef has been examined with special reference to the apical groove and three-dimensional structure of the flagellar apparatus. The apical groove is U-shaped and connected to the anterior...

  6. Transcriptional Analysis of the MrpJ Network: Modulation of Diverse Virulence-Associated Genes and Direct Regulation of mrp Fimbrial and flhDC Flagellar Operons in Proteus mirabilis

    Science.gov (United States)

    Bode, Nadine J.; Debnath, Irina; Kuan, Lisa; Schulfer, Anjelique; Ty, Maureen

    2015-01-01

    The enteric bacterium Proteus mirabilis is associated with a significant number of catheter-associated urinary tract infections (UTIs). Strict regulation of the antagonistic processes of adhesion and motility, mediated by fimbriae and flagella, respectively, is essential for disease progression. Previously, the transcriptional regulator MrpJ, which is encoded by the mrp fimbrial operon, has been shown to repress both swimming and swarming motility. Here we show that MrpJ affects an array of cellular processes beyond adherence and motility. Microarray analysis found that expression of mrpJ mimicking levels observed during UTIs leads to differential expression of 217 genes related to, among other functions, bacterial virulence, type VI secretion, and metabolism. We probed the molecular mechanism of transcriptional regulation by MrpJ using transcriptional reporters and chromatin immunoprecipitation (ChIP). Binding of MrpJ to two virulence-associated target gene promoters, the promoters of the flagellar master regulator flhDC and mrp itself, appears to be affected by the condensation state of the native chromosome, although both targets share a direct MrpJ binding site proximal to the transcriptional start. Furthermore, an mrpJ deletion mutant colonized the bladders of mice at significantly lower levels in a transurethral model of infection. Additionally, we observed that mrpJ is widely conserved in a collection of recent clinical isolates. Altogether, these findings support a role of MrpJ as a global regulator of P. mirabilis virulence. PMID:25847961

  7. Molybdenum-99-producing 37-element fuel bundle neutronically and thermal-hydraulically equivalent to a standard CANDU fuel bundle

    Energy Technology Data Exchange (ETDEWEB)

    Nichita, E., E-mail: Eleodor.Nichita@uoit.ca; Haroon, J., E-mail: Jawad.Haroon@uoit.ca

    2016-10-15

    Highlights: • A 37-element fuel bundle modified for {sup 99}Mo production in CANDU reactors is presented. • The modified bundle is neutronically and thermal-hydraulically equivalent to the standard bundle. • The modified bundle satisfies all safety criteria satisfied by the standard bundle. - Abstract: {sup 99m}Tc, the most commonly used radioisotope in diagnostic nuclear medicine, results from the radioactive decay of {sup 99}Mo which is currently being produced at various research reactors around the globe. In this study, the potential use of CANDU power reactors for the production of {sup 99}Mo is investigated. A modified 37-element fuel bundle, suitable for the production of {sup 99}Mo in existing CANDU-type reactors is proposed. The new bundle is specifically designed to be neutronically and thermal-hydraulically equivalent to the standard 37-element CANDU fuel bundle in normal, steady-state operation and, at the same time, be able to produce significant quantities of {sup 99}Mo when irradiated in a CANDU reactor. The proposed bundle design uses fuel pins consisting of a depleted-uranium centre surrounded by a thin layer of low-enriched uranium. The new molybdenum-producing bundle is analyzed using the lattice transport code DRAGON and the diffusion code DONJON. The proposed design is shown to produce 4081 six-day Curies of {sup 99}Mo activity per bundle when irradiated in the peak-power channel of a CANDU core, while maintaining the necessary reactivity and power rating limits. The calculated {sup 99}Mo yield corresponds to approximately one third of the world weekly demand. A production rate of ∼3 bundles per week can meet the global demand of {sup 99}Mo.

  8. Confinement-Dependent Friction in Peptide Bundles

    Science.gov (United States)

    Erbaş, Aykut; Netz, Roland R.

    2013-01-01

    Friction within globular proteins or between adhering macromolecules crucially determines the kinetics of protein folding, the formation, and the relaxation of self-assembled molecular systems. One fundamental question is how these friction effects depend on the local environment and in particular on the presence of water. In this model study, we use fully atomistic MD simulations with explicit water to obtain friction forces as a single polyglycine peptide chain is pulled out of a bundle of k adhering parallel polyglycine peptide chains. The whole system is periodically replicated along the peptide axes, so a stationary state at prescribed mean sliding velocity V is achieved. The aggregation number is varied between k = 2 (two peptide chains adhering to each other with plenty of water present at the adhesion sites) and k = 7 (one peptide chain pulled out from a close-packed cylindrical array of six neighboring peptide chains with no water inside the bundle). The friction coefficient per hydrogen bond, extrapolated to the viscous limit of vanishing pulling velocity V → 0, exhibits an increase by five orders of magnitude when going from k = 2 to k = 7. This dramatic confinement-induced friction enhancement we argue to be due to a combination of water depletion and increased hydrogen-bond cooperativity. PMID:23528088

  9. Safety assessment for the CANFLEX-NU fuel bundles with respect to the 37-element fuel bundles

    Energy Technology Data Exchange (ETDEWEB)

    Suk, H. C.; Lim, H. S. [Korea Atomic Energy Research Institute, Taejon (Korea)

    1999-11-01

    The KAERI and AECL have jointly developed an advanced CANDU fuel, called CANFLEX-NU fuel bundle. CANFLEX 43-element bundle has some improved features of increased operating margin and enhanced safety compared to the existing 37-element bundle. Since CANFLEX fuel bundle is designed to be compatible with the CANDU-6 reactor design, the behaviour in the thermalhydraulic system will be nearly identical with 37-element bundle. But due to different element design and linear element power distribution between the two bundles, it is expected that CANFLEX fuel behaviour would be different from the behaviour of the 37-element fuel. Therefore, safety assessments on the design basis accidents which result if fuel failures are performed. For all accidents selected, it is observed that the loading of CANFLEX bundle in an existing CANDU-6 reactor would not worsen the reactor safety. It is also predicted that fission product release for CANFLEX fuel bundle generally is lower than that for 37-element bundle. 3 refs., 2 figs., 2 tabs. (Author)

  10. Real-time wavelet-based inline banknote-in-bundle counting for cut-and-bundle machines

    Science.gov (United States)

    Petker, Denis; Lohweg, Volker; Gillich, Eugen; Türke, Thomas; Willeke, Harald; Lochmüller, Jens; Schaede, Johannes

    2011-03-01

    Automatic banknote sheet cut-and-bundle machines are widely used within the scope of banknote production. Beside the cutting-and-bundling, which is a mature technology, image-processing-based quality inspection for this type of machine is attractive. We present in this work a new real-time Touchless Counting and perspective cutting blade quality insurance system, based on a Color-CCD-Camera and a dual-core Computer, for cut-and-bundle applications in banknote production. The system, which applies Wavelet-based multi-scale filtering is able to count banknotes inside a 100-bundle within 200-300 ms depending on the window size.

  11. Evaluation of Single-Bundle versus Double-Bundle PCL Reconstructions with More Than 10-Year Follow-Up

    Directory of Open Access Journals (Sweden)

    Masataka Deie

    2015-01-01

    Full Text Available Background. Posterior cruciate ligament (PCL injuries are not rare in acute knee injuries, and several recent anatomical studies of the PCL and reconstructive surgical techniques have generated improved patient results. Now, we have evaluated PCL reconstructions performed by either the single-bundle or double-bundle technique in a patient group followed up retrospectively for more than 10 years. Methods. PCL reconstructions were conducted using the single-bundle (27 cases or double-bundle (13 cases method from 1999 to 2002. The mean age at surgery was 34 years in the single-bundle group and 32 years in the double-bundle group. The mean follow-up period was 12.5 years. Patients were evaluated by Lysholm scoring, the gravity sag view, and knee arthrometry. Results. The Lysholm score after surgery was 89.1±5.6 points for the single-bundle group and 91.9±4.5 points for the double-bundle group. There was no significant difference between the methods in the side-to-side differences by gravity sag view or knee arthrometer evaluation, although several cases in both groups showed a side-to-side difference exceeding 5 mm by the latter evaluation method. Conclusions. We found no significant difference between single- and double-bundle PCL reconstructions during more than 10 years of follow-up.

  12. BACTERIAL CONSORTIUM

    Directory of Open Access Journals (Sweden)

    Payel Sarkar

    2013-01-01

    Full Text Available Petroleum aromatic hydrocarbons like benzen e, toluene, ethyl benzene and xylene, together known as BTEX, has almost the same chemical structure. These aromatic hydrocarbons are released as pollutants in th e environment. This work was taken up to develop a solvent tolerant bacterial cons ortium that could degrade BTEX compounds as they all share a common chemical structure. We have isolated almost 60 different types of bacterial strains from different petroleum contaminated sites. Of these 60 bacterial strains almost 20 microorganisms were screene d on the basis of capability to tolerate high concentration of BTEX. Ten differe nt consortia were prepared and the compatibility of the bacterial strains within the consortia was checked by gram staining and BTEX tolerance level. Four successful mi crobial consortia were selected in which all the bacterial strains concomitantly grew in presence of high concentration of BTEX (10% of toluene, 10% of benzene 5% ethyl benzene and 1% xylene. Consortium #2 showed the highest growth rate in pr esence of BTEX. Degradation of BTEX by consortium #2 was monitored for 5 days by gradual decrease in the volume of the solvents. The maximum reduction observed wa s 85% in 5 days. Gas chromatography results also reveal that could completely degrade benzene and ethyl benzene within 48 hours. Almost 90% degradation of toluene and xylene in 48 hours was exhibited by consortium #2. It could also tolerate and degrade many industrial solvents such as chloroform, DMSO, acetonitrile having a wide range of log P values (0.03–3.1. Degradation of aromatic hydrocarbon like BTEX by a solvent tolerant bacterial consortium is greatly significant as it could degrade high concentration of pollutants compared to a bacterium and also reduces the time span of degradation.

  13. Moduli of Parabolic Higgs Bundles and Atiyah Algebroids

    DEFF Research Database (Denmark)

    Logares, Marina; Martens, Johan

    2010-01-01

    In this paper we study the geometry of the moduli space of (non-strongly) parabolic Higgs bundles over a Riemann surface with marked points. We show that this space possesses a Poisson structure, extending the one on the dual of an Atiyah algebroid over the moduli space of parabolic vector bundle...

  14. Infinite Grassmannian and moduli space of G-bundles

    International Nuclear Information System (INIS)

    Kumar, S.; Ramanathan, A.

    1993-03-01

    Let C be a smooth irreducible projective curve and G a simply connected simple affine algebraic group of C. We study in this paper the relationship between the space of vacua defined in Conformal Field Theory and the space of sections of a line bundle on the moduli space of G-bundles over C. (author). 33 refs

  15. Monoubiquitination Inhibits the Actin Bundling Activity of Fascin.

    Science.gov (United States)

    Lin, Shengchen; Lu, Shuang; Mulaj, Mentor; Fang, Bin; Keeley, Tyler; Wan, Lixin; Hao, Jihui; Muschol, Martin; Sun, Jianwei; Yang, Shengyu

    2016-12-30

    Fascin is an actin bundling protein that cross-links individual actin filaments into straight, compact, and stiff bundles, which are crucial for the formation of filopodia, stereocillia, and other finger-like membrane protrusions. The dysregulation of fascin has been implicated in cancer metastasis, hearing loss, and blindness. Here we identified monoubiquitination as a novel mechanism that regulates fascin bundling activity and dynamics. The monoubiquitination sites were identified to be Lys 247 and Lys 250 , two residues located in a positive charge patch at the actin binding site 2 of fascin. Using a chemical ubiquitination method, we synthesized chemically monoubiquitinated fascin and determined the effects of monoubiquitination on fascin bundling activity and dynamics. Our data demonstrated that monoubiquitination decreased the fascin bundling EC 50 , delayed the initiation of bundle assembly, and accelerated the disassembly of existing bundles. By analyzing the electrostatic properties on the solvent-accessible surface of fascin, we proposed that monoubiquitination introduced steric hindrance to interfere with the interaction between actin filaments and the positively charged patch at actin binding site 2. We also identified Smurf1 as a E3 ligase regulating the monoubiquitination of fascin. Our findings revealed a previously unidentified regulatory mechanism for fascin, which will have important implications for the understanding of actin bundle regulation under physiological and pathological conditions. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

  16. Monoubiquitination Inhibits the Actin Bundling Activity of Fascin*

    Science.gov (United States)

    Lin, Shengchen; Lu, Shuang; Mulaj, Mentor; Fang, Bin; Keeley, Tyler; Wan, Lixin; Hao, Jihui; Muschol, Martin; Sun, Jianwei; Yang, Shengyu

    2016-01-01

    Fascin is an actin bundling protein that cross-links individual actin filaments into straight, compact, and stiff bundles, which are crucial for the formation of filopodia, stereocillia, and other finger-like membrane protrusions. The dysregulation of fascin has been implicated in cancer metastasis, hearing loss, and blindness. Here we identified monoubiquitination as a novel mechanism that regulates fascin bundling activity and dynamics. The monoubiquitination sites were identified to be Lys247 and Lys250, two residues located in a positive charge patch at the actin binding site 2 of fascin. Using a chemical ubiquitination method, we synthesized chemically monoubiquitinated fascin and determined the effects of monoubiquitination on fascin bundling activity and dynamics. Our data demonstrated that monoubiquitination decreased the fascin bundling EC50, delayed the initiation of bundle assembly, and accelerated the disassembly of existing bundles. By analyzing the electrostatic properties on the solvent-accessible surface of fascin, we proposed that monoubiquitination introduced steric hindrance to interfere with the interaction between actin filaments and the positively charged patch at actin binding site 2. We also identified Smurf1 as a E3 ligase regulating the monoubiquitination of fascin. Our findings revealed a previously unidentified regulatory mechanism for fascin, which will have important implications for the understanding of actin bundle regulation under physiological and pathological conditions. PMID:27879315

  17. An overview on rod-bundle thermal-hydraulic analyses

    International Nuclear Information System (INIS)

    Sha, W.T.

    1980-01-01

    Three methods used in rod-bundle thermal-hydraulic analysis are summarized. These methods are: (1) subchannel analysis, (2) porous medium formulation with volume porosity, surface permeability, distributed resistance and distributed heat source (sink) and, (3) bench-mark rod-bundle thermal-hydraulic analysis using a boundary-fitted coordinate system. Basic limitations and merits of each method are delineated. (orig.)

  18. Computational imaging through a fiber-optic bundle

    Science.gov (United States)

    Lodhi, Muhammad A.; Dumas, John Paul; Pierce, Mark C.; Bajwa, Waheed U.

    2017-05-01

    Compressive sensing (CS) has proven to be a viable method for reconstructing high-resolution signals using low-resolution measurements. Integrating CS principles into an optical system allows for higher-resolution imaging using lower-resolution sensor arrays. In contrast to prior works on CS-based imaging, our focus in this paper is on imaging through fiber-optic bundles, in which manufacturing constraints limit individual fiber spacing to around 2 μm. This limitation essentially renders fiber-optic bundles as low-resolution sensors with relatively few resolvable points per unit area. These fiber bundles are often used in minimally invasive medical instruments for viewing tissue at macro and microscopic levels. While the compact nature and flexibility of fiber bundles allow for excellent tissue access in-vivo, imaging through fiber bundles does not provide the fine details of tissue features that is demanded in some medical situations. Our hypothesis is that adapting existing CS principles to fiber bundle-based optical systems will overcome the resolution limitation inherent in fiber-bundle imaging. In a previous paper we examined the practical challenges involved in implementing a highly parallel version of the single-pixel camera while focusing on synthetic objects. This paper extends the same architecture for fiber-bundle imaging under incoherent illumination and addresses some practical issues associated with imaging physical objects. Additionally, we model the optical non-idealities in the system to get lower modelling errors.

  19. The behaviour of Phenix fuel pin bundle under irradiation

    International Nuclear Information System (INIS)

    Marbach, G.; Millet, P.; Blanchard, P.; Huillery, R.

    1979-07-01

    An entire Phenix sub-assembly has been mounted and sectioned after irradiation. The examination of cross-sections revealed the effects of mechanical interaction in the bundle (ovalisations and contacts between clads). According to analysis of the sodium channels, cooling of the pin bundle remained uniform. (author)

  20. Smooth Bundling of Large Streaming and Sequence Graphs

    NARCIS (Netherlands)

    Hurter, C.; Ersoy, O.; Telea, A.

    2013-01-01

    Dynamic graphs are increasingly pervasive in modern information systems. However, understanding how a graph changes in time is difficult. We present here two techniques for simplified visualization of dynamic graphs using edge bundles. The first technique uses a recent image-based graph bundling

  1. Two-categorical bundles and their classifying spaces

    DEFF Research Database (Denmark)

    Baas, Nils A.; Bökstedt, M.; Kro, T.A.

    2012-01-01

    -category is a classifying space for the associated principal 2-bundles. In the process of proving this we develop a lot of powerful machinery which may be useful in further studies of 2-categorical topology. As a corollary we get a new proof of the classification of principal bundles. A calculation based...

  2. Multi-bundle shashlik calorimeter prototypes beam-test results

    International Nuclear Information System (INIS)

    Badier, J.; Bloch, P.; Bityukov, S.; Bordalo, P.; Busson, P.; Charlot, C.; Dobrzynski, L.; Golutvin, I.; Guschin, E.; Issakov, V.; Ivanchenko, I.; Klimenko, V.; Marin, V.; Moissenz, P.; Obraztsov, V.; Ostankov, A.; Popov, V.; Puljak, I.; Ramos, S.; Seez, C.; Sergueev, S.; Soushkov, V.; Tanaka, R.; Varela, J.; Virdee, T.S.; Zaitchenko, A.; Zamiatin, N.

    1995-01-01

    The first beam-test results for two- and three-bundle shashlik tower prototypes are described. We found that the spatial resolution, the uniformity of energy response, the calorimeter reliability and hermeticity and also two showers separation are improved in multi-bundle design approach. ((orig.))

  3. Stability of Picard Bundle Over Moduli Space of Stable Vector ...

    Indian Academy of Sciences (India)

    Abstract. Answering a question of [BV] it is proved that the Picard bundle on the moduli space of stable vector bundles of rank two, on a Riemann surface of genus at least three, with fixed determinant of odd degree is stable.

  4. Tokyo Guidelines 2018: management bundles for acute cholangitis and cholecystitis

    NARCIS (Netherlands)

    Mayumi, Toshihiko; Okamoto, Kohji; Takada, Tadahiro; Strasberg, Steven M.; Solomkin, Joseph S.; Schlossberg, David; Pitt, Henry A.; Yoshida, Masahiro; Gomi, Harumi; Miura, Fumihiko; Garden, O. James; Kiriyama, Seiki; Yokoe, Masamichi; Endo, Itaru; Asbun, Horacio J.; Iwashita, Yukio; Hibi, Taizo; Umezawa, Akiko; Suzuki, Kenji; Itoi, Takao; Hata, Jiro; Han, Ho-Seong; Hwang, Tsann-Long; Dervenis, Christos; Asai, Koji; Mori, Yasuhisa; Huang, Wayne Shih-Wei; Belli, Giulio; Mukai, Shuntaro; Jagannath, Palepu; Cherqui, Daniel; Kozaka, Kazuto; Baron, Todd H.; de Santibañes, Eduardo; Higuchi, Ryota; Wada, Keita; Gouma, Dirk J.; Deziel, Daniel J.; Liau, Kui-Hin; Wakabayashi, Go; Padbury, Robert; Jonas, Eduard; Supe, Avinash Nivritti; Singh, Harjit; Gabata, Toshifumi; Chan, Angus C. W.; Lau, Wan Yee; Fan, Sheung Tat; Chen, Miin-Fu; Ker, Chen-Guo; Yoon, Yoo-Seok; Choi, In-Seok; Kim, Myung-Hwan; Yoon, Dong-Sup; Kitano, Seigo; Inomata, Masafumi; Hirata, Koichi; Inui, Kazuo; Sumiyama, Yoshinobu; Yamamoto, Masakazu

    2018-01-01

    Management bundles that define items or procedures strongly recommended in clinical practice have been used in many guidelines in recent years. Application of these bundles facilitates the adaptation of guidelines and helps improve the prognosis of target diseases. In Tokyo Guidelines 2013 (TG13),

  5. The avalanche process of the multilinear fiber bundles model

    International Nuclear Information System (INIS)

    Hao, Da-Peng; Tang, Gang; Xun, Zhi-Peng; Xia, Hui; Han, Kui

    2012-01-01

    In order to describe the smooth nonlinear constitutive behavior in the process of fracture of ductile micromechanics structures, the multilinear fiber bundle model was constructed, based on the bilinear fiber bundle model. In the multilinear fiber bundle model, the Young modulus of a fiber is assumed to decay K max times before the final failure occurs. For the large K max region, this model can describe the smooth nonlinear constitutive behavior well. By means of analytical approximation and numerical simulation, we show that the two critical parameters, i.e. the decay ratio of the Young modulus and the maximum number of decays, have substantial effects on the failure process of the bundle. From a macroscopic view, the model can provide various shapes of constitutive curves, which represent diverse kinds of tensile fracture processes. However, at the microscopic scale, the statistical properties of the model are in accord with the classical fiber bundle model. (paper)

  6. Introduction to the theory of fiber bundles and connections I

    International Nuclear Information System (INIS)

    Socolvsky, M.

    1990-01-01

    In lectures 1 and 2 we discuss basic concepts of topology and differential geometry: definition of a topological space and of Hausdorff, compact, connected and paracompact spaces; topological groups and actions of groups on spaces; differentiable manifolds, tangent vectors and 1 forms; partitions of unity and Lie groups. In lecture 3 we present the concept of a fiber bundle and discuss vector bundles and principal bundles. The concept of a connection on a smooth vector bundle is defined in lecture 4, together with the associated concepts of curvature and parallel transport; as an illustration we present the Levi-Civita connection on a Riemannian manifold. Finally, in lecture 5 we define connections on principal bundles and present examples with the Lie groups U(1) and SU(2). For reasons of space the present article only includes lectures 1, 2 and 3. Lectures 4 and 5 will be published in a forthcoming paper. (Author)

  7. Bundles over Quantum RealWeighted Projective Spaces

    Directory of Open Access Journals (Sweden)

    Tomasz Brzeziński

    2012-09-01

    Full Text Available The algebraic approach to bundles in non-commutative geometry and the definition of quantum real weighted projective spaces are reviewed. Principal U(1-bundles over quantum real weighted projective spaces are constructed. As the spaces in question fall into two separate classes, the negative or odd class that generalises quantum real projective planes and the positive or even class that generalises the quantum disc, so do the constructed principal bundles. In the negative case the principal bundle is proven to be non-trivial and associated projective modules are described. In the positive case the principal bundles turn out to be trivial, and so all the associated modules are free. It is also shown that the circle (coactions on the quantum Seifert manifold that define quantum real weighted projective spaces are almost free.

  8. Development and Assessment of a Bundle Correction Method for CHF

    International Nuclear Information System (INIS)

    Hwang, Dae Hyun; Chang, Soon Heung

    1993-01-01

    A bundle correction method, based on the conservation laws of mass, energy, and momentum in an open subchannel, is proposed for the prediction of the critical heat flux (CHF) in rod bundles from round tube CHF correlations without detailed subchannel analysis. It takes into account the effects of the enthalpy and mass velocity distributions at subchannel level using the first dericatives of CHF with respect to the independent parameters. Three different CHF correlations for tubes (Groeneveld's CHF table, Katto correlation, and Biasi correlation) have been examined with uniformly heated bundle CHF data collected from various sources. A limited number of GHE data from a non-uniformly heated rod bundle are also evaluated with the aid of Tong's F-factor. The proposed method shows satisfactory CHF predictions for rod bundles both uniform and non-uniform power distributions. (Author)

  9. Development of nuclear fuel. Development of CANDU advanced fuel bundle

    International Nuclear Information System (INIS)

    Suk, Ho Chun; Hwang, Woan; Jeong, Young Hwan; Jung, Sung Hoon

    1991-07-01

    In order to develop CANDU advanced fuel, the agreement of the joint research between KAERI and AECL was made on February 19, 1991. AECL conceptual design of CANFLEX bundle for Bruce reactors was analyzed and then the reference design and design drawing of the advanced fuel bundle with natural uranium fuel for CANDU-6 reactor were completed. The CANFLEX fuel cladding was preliminarily investigated. The fabricability of the advanced fuel bundle was investigated. The design and purchase of the machinery tools for the bundle fabrication for hydraulic scoping tests were performed. As a result of CANFLEX tube examination, the tubes were found to be meet the criteria proposed in the technical specification. The dummy bundles for hydraulic scoping tests have been fabricated by using the process and tools, where the process parameters and tools have been newly established. (Author)

  10. Superconductivity in an Inhomogeneous Bundle of Metallic and Semiconducting Nanotubes

    Directory of Open Access Journals (Sweden)

    Ilya Grigorenko

    2013-01-01

    Full Text Available Using Bogoliubov-de Gennes formalism for inhomogeneous systems, we have studied superconducting properties of a bundle of packed carbon nanotubes, making a triangular lattice in the bundle's transverse cross-section. The bundle consists of a mixture of metallic and doped semiconducting nanotubes, which have different critical transition temperatures. We investigate how a spatially averaged superconducting order parameter and the critical transition temperature depend on the fraction of the doped semiconducting carbon nanotubes in the bundle. Our simulations suggest that the superconductivity in the bundle will be suppressed when the fraction of the doped semiconducting carbon nanotubes will be less than 0.5, which is the percolation threshold for a two-dimensional triangular lattice.

  11. CFD modeling of secondary flows in fuel rod bundles

    International Nuclear Information System (INIS)

    Baglietto, Emilio; Ninokata, Hisashi

    2004-01-01

    An optimized non-linear eddy viscosity model is introduced, for calculations of detailed coolant velocity distribution in a tight lattice fuel bundle. The low Reynolds formulation has been optimized based on DNS data for channel flow. The non-linear stress-strain relationship has been modified in the coefficients to model the flow anisotropy, which causes the formation of turbulence driven secondary flows inside the bundle subchannels. Predictions of the model are first compared to experimental measurements of secondary flows in a triangularly arrayed rod bundle with p/d=1.3. Subsequently wall shear stress and velocity predictions are compared with different experimental data for a rod bundle with p/d=1.17. The model shows to be able to correctly reproduce the scale of the secondary motion, and to accurately reproduce both wall shear stress and velocity distributions inside the rod bundle subchannels. (author)

  12. Wire-wrap bundle compression-characteristics study. Phase I

    International Nuclear Information System (INIS)

    Chertock, A.J.

    1974-06-01

    An analytical computer comparison was made of the compression characteristics of proposed wire-wrap bundles. The study included analysis of 7- and 37-rod straight-start bundles (base configuration), and softened 37-rod configurations. The softened configurations analyzed were: straight-start with distributed wireless fuel rods, and the staggered wire-wrap start angles of 0 0 -30 0 -60 0 and 0 0 -45 0 -90 0 . The compression of the bundle simulates the bundle-to-channel interference at end-of-life conditions at which high differential swelling between the channel and bundle has been predicted. The computer results do not include the so-called dispersion effects. The effects of other variables such as pitch length, creep, axial variations in swelling, and degree of swelling were not studied. These analytic studies give an indication of trends only. No credence should be given to specific quantitative load or deflection results quoted in this report

  13. FliD. : Exploring the flagellar tip protein as a target against Campylobacter jejuni

    NARCIS (Netherlands)

    Freitag, C.M.|info:eu-repo/dai/nl/412516802

    2017-01-01

    Campylobacter jejuni is most common bacterial agent causing human diarrhea. Symptoms can range from mild colitis to severe bloody enteritis with abdominal cramping. Chickens represent the main reservoir of C. jejuni and contaminated meat products are an important source of human infection. In order

  14. Vision, healing brush, and fiber bundles

    Science.gov (United States)

    Georgiev, Todor

    2005-03-01

    The Healing Brush is a tool introduced for the first time in Adobe Photoshop (2002) that removes defects in images by seamless cloning (gradient domain fusion). The Healing Brush algorithms are built on a new mathematical approach that uses Fibre Bundles and Connections to model the representation of images in the visual system. Our mathematical results are derived from first principles of human vision, related to adaptation transforms of von Kries type and Retinex theory. In this paper we present the new result of Healing in arbitrary color space. In addition to supporting image repair and seamless cloning, our approach also produces the exact solution to the problem of high dynamic range compression of17 and can be applied to other image processing algorithms.

  15. Big things come in bundled packages: implications of bundled payment systems in health care reimbursement reform.

    Science.gov (United States)

    Delisle, Dennis R

    2013-01-01

    With passage of the Affordable Care Act, the ever-evolving landscape of health care braces for another shift in the reimbursement paradigm. As health care costs continue to rise, providers are pressed to deliver efficient, high-quality care at flat to minimally increasing rates. Inherent systemwide inefficiencies between payers and providers at various clinical settings pose a daunting task for enhancing collaboration and care coordination. A change from Medicare's fee-for-service reimbursement model to bundled payments offers one avenue for resolution. Pilots using such payment models have realized varying degrees of success, leading to the development and upcoming implementation of a bundled payment initiative led by the Center for Medicare and Medicaid Innovation. Delivery integration is critical to ensure high-quality care at affordable costs across the system. Providers and payers able to adapt to the newly proposed models of payment will benefit from achieving cost reductions and improved patient outcomes and realize a competitive advantage.

  16. Birefringence of single and bundled microtubules.

    Science.gov (United States)

    Oldenbourg, R; Salmon, E D; Tran, P T

    1998-01-01

    We have measured the birefringence of microtubules (MTs) and of MT-based macromolecular assemblies in vitro and in living cells by using the new Pol-Scope. A single microtubule in aqueous suspension and imaged with a numerical aperture of 1.4 had a peak retardance of 0.07 nm. The peak retardance of a small bundle increased linearly with the number of MTs in the bundle. Axonemes (prepared from sea urchin sperm) had a peak retardance 20 times higher than that of single MTs, in accordance with the nine doublets and two singlets arrangement of parallel MTs in the axoneme. Measured filament retardance decreased when the filament was defocused or the numerical aperture of the imaging system was decreased. However, the retardance "area," which we defined as the image retardance integrated along a line perpendicular to the filament axis, proved to be independent of focus and of numerical aperture. These results are in good agreement with a theory that we developed for measuring retardances with imaging optics. Our theoretical concept is based on Wiener's theory of mixed dielectrics, which is well established for nonimaging applications. We extend its use to imaging systems by considering the coherence region defined by the optical set-up. Light scattered from within that region interferes coherently in the image point. The presence of a filament in the coherence region leads to a polarization dependent scattering cross section and to a finite retardance measured in the image point. Similar to resolution measurements, the linear dimension of the coherence region for retardance measurements is on the order lambda/(2 NA), where lambda is the wavelength of light and NA is the numerical aperture of the illumination and imaging lenses.

  17. Restriction of Preferences to the Set of Consumption Bundles, In a Model with Production and Consumption Bundles

    NARCIS (Netherlands)

    Schalk, S.

    1999-01-01

    In contrast to the neo-classical theory of Arrow and Debreu, a model of a private ownership economy is presented, in which production and consumption bundles are treated separately. Each of the two types of bundles is assumed to establish a con- vex cone. Production technologies can convert

  18. Surgical anatomy of the atrioventricular conduction bundle in anomalous muscle bundle of the right ventricle with subarterial ventricular septal defect

    NARCIS (Netherlands)

    Kurosawa, H.; Becker, A. E.

    1985-01-01

    A stillborn baby girl was found to have an anomalous muscle bundle of the right ventricle, associated with a doubly committed subarterial ventricular septal defect. The latter was separated from the area of the atrioventricular conduction bundle by muscle. Serial histologic sectioning of the

  19. Interaction between the flagellar pocket collar and the hook complex via a novel microtubule-binding protein in Trypanosoma brucei.

    Directory of Open Access Journals (Sweden)

    Anna Albisetti

    2017-11-01

    Full Text Available Trypanosoma brucei belongs to a group of unicellular, flagellated parasites that are responsible for human African trypanosomiasis. An essential aspect of parasite pathogenicity is cytoskeleton remodelling, which occurs during the life cycle of the parasite and is accompanied by major changes in morphology and organelle positioning. The flagellum originates from the basal bodies and exits the cell body through the flagellar pocket (FP but remains attached to the cell body via the flagellum attachment zone (FAZ. The FP is an invagination of the pellicular membrane and is the sole site for endo- and exocytosis. The FAZ is a large complex of cytoskeletal proteins, plus an intracellular set of four specialised microtubules (MtQ that elongate from the basal bodies to the anterior end of the cell. At the distal end of the FP, an essential, intracellular, cytoskeletal structure called the flagellar pocket collar (FPC circumvents the flagellum. Overlapping the FPC is the hook complex (HC (a sub-structure of the previously named bilobe that is also essential and is thought to be involved in protein FP entry. BILBO1 is the only functionally characterised FPC protein and is necessary for FPC and FP biogenesis. Here, we used a combination of in vitro and in vivo approaches to identify and characterize a new BILBO1 partner protein-FPC4. We demonstrate that FPC4 localises to the FPC, the HC, and possibly to a proximal portion of the MtQ. We found that the C-terminal domain of FPC4 interacts with the BILBO1 N-terminal domain, and we identified the key amino acids required for this interaction. Interestingly, the FPC4 N-terminal domain was found to bind microtubules. Over-expression studies highlight the role of FPC4 in its association with the FPC, HC and FPC segregation. Our data suggest a tripartite association between the FPC, the HC and the MtQ.

  20. Cationic amino acid uptake constitutes a metabolic regulation mechanism and occurs in the flagellar pocket of Trypanosoma cruzi.

    Directory of Open Access Journals (Sweden)

    Mariana R Miranda

    Full Text Available Trypanosomatids' amino acid permeases are key proteins in parasite metabolism since they participate in the adaptation of parasites to different environments. Here, we report that TcAAP3, a member of a Trypanosoma cruzi multigene family of permeases, is a bona fide arginine transporter. Most higher eukaryotic cells incorporate cationic amino acids through a single transporter. In contrast, T. cruzi can recognize and transport cationic amino acids by mono-specific permeases since a 100-fold molar excess of lysine could not affect the arginine transport in parasites that over-express the arginine permease (TcAAP3 epimastigotes. In order to test if the permease activity regulates downstream processes of the arginine metabolism, the expression of the single T. cruzi enzyme that uses arginine as substrate, arginine kinase, was evaluated in TcAAP3 epimastigotes. In this parasite model, intracellular arginine concentration increases 4-folds and ATP level remains constant until cultures reach the stationary phase of growth, with decreases of about 6-folds in respect to the controls. Interestingly, Western Blot analysis demonstrated that arginine kinase is significantly down-regulated during the stationary phase of growth in TcAAP3 epimastigotes. This decrease could represent a compensatory mechanism for the increase in ATP consumption as a consequence of the displacement of the reaction equilibrium of arginine kinase, when the intracellular arginine concentration augments and the glucose from the medium is exhausted. Using immunofluorescence techniques we also determined that TcAAP3 and the specific lysine transporter TcAAP7 co-localize in a specialized region of the plasma membrane named flagellar pocket, staining a single locus close to the flagellar pocket collar. Taken together these data suggest that arginine transport is closely related to arginine metabolism and cell energy balance. The clinical relevance of studying trypanosomatids' permeases

  1. Two Types of Genetic Interaction Implicate the Whirligig Gene of Drosophila Melanogaster in Microtubule Organization in the Flagellar Axoneme

    Science.gov (United States)

    Green, L. L.; Wolf, N.; McDonald, K. L.; Fuller, M. T.

    1990-01-01

    The mutant nc4 allele of whirligig (3-54.4) of Drosophila melanogaster fails to complement mutations in an α-tubulin locus, α1t, mutations in a β-tubulin locus, B2t, or a mutation in the haywire locus. However, wrl fails to map to any of the known α- or β-tubulin genes. The extragenic failure to complement could indicate that the wrl product participates in structural interactions with microtubule proteins. The whirligig locus appears to be haploinsufficient for male fertility. Both a deficiency of wrl and possible loss of function alleles obtained by reverting the failure to complement between wrl(nc4) and B2t(n) are dominant male sterile in a genetic background wild type for tubulin. The dominant male sterility of the revertant alleles is suppressed if the flies are also heterozygous for B2t(n), for a deficiency of α1t, or for the hay(nc2) allele. These results suggest that it is not the absolute level of wrl gene product but its level relative to tubulin or microtubule function that is important for normal spermatogenesis. The phenotype of homozygous wrl mutants suggests that the whirligig product plays a role in postmeiotic spermatid differentiation, possibly in organizing the microtubules of the sperm flagellar axoneme. Flies homozygous for either wrl(nc4) or revertant alleles are viable and female fertile but male sterile. Premeiotic and meiotic stages of spermatogenesis appear normal. However, in post-meiotic stages, flagellar axonemes show loss of the accessory microtubule on the B-subfiber of outer doublet microtubules, outer triplet instead of outer doublet microtubules, and missing central pair microtubules. PMID:2127579

  2. Bacterial Adhesion & Blocking Bacterial Adhesion

    DEFF Research Database (Denmark)

    Vejborg, Rebecca Munk

    2008-01-01

    , which influence the transition from a planktonic lifestyle to a sessile lifestyle, have been studied. Protein conditioning film formation was found to influence bacterial adhesion and subsequent biofilm formation considerable, and an aqueous extract of fish muscle tissue was shown to significantly...... tract to the microbial flocs in waste water treatment facilities. Microbial biofilms may however also cause a wide range of industrial and medical problems, and have been implicated in a wide range of persistent infectious diseases, including implantassociated microbial infections. Bacterial adhesion...... is the first committing step in biofilm formation, and has therefore been intensely scrutinized. Much however, still remains elusive. Bacterial adhesion is a highly complex process, which is influenced by a variety of factors. In this thesis, a range of physico-chemical, molecular and environmental parameters...

  3. Bacterial meningitis

    NARCIS (Netherlands)

    Heckenberg, Sebastiaan G. B.; Brouwer, Matthijs C.; van de Beek, Diederik

    2014-01-01

    Bacterial meningitis is a neurologic emergency. Vaccination against common pathogens has decreased the burden of disease. Early diagnosis and rapid initiation of empiric antimicrobial and adjunctive therapy are vital. Therapy should be initiated as soon as blood cultures have been obtained,

  4. Bacterial lipases

    NARCIS (Netherlands)

    Jaeger, Karl-Erich; Ransac, Stéphane; Dijkstra, Bauke W.; Colson, Charles; Heuvel, Margreet van; Misset, Onno

    Many different bacterial species produce lipases which hydrolyze esters of glycerol with preferably long-chain fatty acids. They act at the interface generated by a hydrophobic lipid substrate in a hydrophilic aqueous medium. A characteristic property of lipases is called interfacial activation,

  5. Bacterial stress

    Indian Academy of Sciences (India)

    First page Back Continue Last page Graphics. Bacterial stress. Physicochemical and chemical parameters: temperature, pressure, pH, salt concentration, oxygen, irradiation. Nutritional depravation: nutrient starvation, water shortage. Toxic compounds: Antibiotics, heavy metals, toxins, mutagens. Interactions with other cells: ...

  6. Cost-effectiveness of a central venous catheter care bundle.

    Directory of Open Access Journals (Sweden)

    Kate A Halton

    Full Text Available BACKGROUND: A bundled approach to central venous catheter care is currently being promoted as an effective way of preventing catheter-related bloodstream infection (CR-BSI. Consumables used in the bundled approach are relatively inexpensive which may lead to the conclusion that the bundle is cost-effective. However, this fails to consider the nontrivial costs of the monitoring and education activities required to implement the bundle, or that alternative strategies are available to prevent CR-BSI. We evaluated the cost-effectiveness of a bundle to prevent CR-BSI in Australian intensive care patients. METHODS AND FINDINGS: A Markov decision model was used to evaluate the cost-effectiveness of the bundle relative to remaining with current practice (a non-bundled approach to catheter care and uncoated catheters, or use of antimicrobial catheters. We assumed the bundle reduced relative risk of CR-BSI to 0.34. Given uncertainty about the cost of the bundle, threshold analyses were used to determine the maximum cost at which the bundle remained cost-effective relative to the other approaches to infection control. Sensitivity analyses explored how this threshold alters under different assumptions about the economic value placed on bed-days and health benefits gained by preventing infection. If clinicians are prepared to use antimicrobial catheters, the bundle is cost-effective if national 18-month implementation costs are below $1.1 million. If antimicrobial catheters are not an option the bundle must cost less than $4.3 million. If decision makers are only interested in obtaining cash-savings for the unit, and place no economic value on either the bed-days or the health benefits gained through preventing infection, these cost thresholds are reduced by two-thirds. CONCLUSIONS: A catheter care bundle has the potential to be cost-effective in the Australian intensive care setting. Rather than anticipating cash-savings from this intervention, decision

  7. Enzymatic hydrolysis of biomimetic bacterial cellulose-hemicellulose composites.

    Science.gov (United States)

    Penttilä, Paavo A; Imai, Tomoya; Hemming, Jarl; Willför, Stefan; Sugiyama, Junji

    2018-06-15

    The production of biofuels and other chemicals from lignocellulosic biomass is limited by the inefficiency of enzymatic hydrolysis. Here a biomimetic composite material consisting of bacterial cellulose and wood-based hemicelluloses was used to study the effects of hemicelluloses on the enzymatic hydrolysis with a commercial cellulase mixture. Bacterial cellulose synthesized in the presence of hemicelluloses, especially xylan, was found to be more susceptible to enzymatic hydrolysis than hemicellulose-free bacterial cellulose. The reason for the easier hydrolysis could be related to the nanoscale structure of the substrate, particularly the packing of cellulose microfibrils into ribbons or bundles. In addition, small-angle X-ray scattering was used to show that the average nanoscale morphology of bacterial cellulose remained unchanged during the enzymatic hydrolysis. The reported easier enzymatic hydrolysis of bacterial cellulose produced in the presence of wood-based xylan offers new insights to overcome biomass recalcitrance through genetic engineering. Copyright © 2018 Elsevier Ltd. All rights reserved.

  8. Equilibrium polyelectrolyte bundles with different multivalent counterion concentrations

    Science.gov (United States)

    Sayar, Mehmet; Holm, Christian

    2010-09-01

    We present the results of molecular-dynamics simulations on the salt concentration dependence of the formation of polyelectrolyte bundles in thermodynamic equilibrium. Extending our results on salt-free systems we investigate here deficiency or excess of trivalent counterions in solution. Our results reveal that the trivalent counterion concentration significantly alters the bundle size and size distribution. The onset of bundle formation takes place at earlier Bjerrum length values with increasing trivalent counterion concentration. For the cases of 80%, 95%, and 100% charge compensation via trivalent counterions, the net charge of the bundles decreases with increasing size. We suggest that competition among two different mechanisms, counterion condensation and merger of bundles, leads to a nonmonotonic change in line-charge density with increasing Bjerrum length. The investigated case of having an abundance of trivalent counterions by 200% prohibits such a behavior. In this case, we find that the difference in effective line-charge density of different size bundles diminishes. In fact, the system displays an isoelectric point, where all bundles become charge neutral.

  9. Single-phase convective heat transfer in rod bundles

    International Nuclear Information System (INIS)

    Holloway, Mary V.; Beasley, Donald E.; Conner, Michael E.

    2008-01-01

    The convective heat transfer for turbulent flow through rod bundles representative of nuclear fuel rods used in pressurized water reactors is examined. The rod bundles consist of a square array of parallel rods that are held on a constant pitch by support grids spaced axially along the rod bundle. Split-vane pair support grids, which create swirling flow in the rod bundle, as well as disc and standard support grids are investigated. Single-phase convective heat transfer coefficients are measured for flow downstream of support grids in a rod bundle. The rods are heated using direct resistance heating, and a bulk axial flow of air is used to cool the rods in the rod bundle. Air is used as the working fluid instead of water to reduce the power required to heat the rod bundle. Results indicate heat transfer enhancement for up to 10 hydraulic diameters downstream of the support grids. A general correlation is developed to predict the heat transfer development downstream of support grids. In addition, circumferential variations in heat transfer coefficients result in hot streaks that develop on the rods downstream of split-vane pair support grids

  10. Single-phase convective heat transfer in rod bundles

    Energy Technology Data Exchange (ETDEWEB)

    Holloway, Mary V. [Mechanical Engineering Department, United States Naval Academy, 590 Holloway Rd., Annapolis, MD 21402 (United States)], E-mail: holloway@usna.edu; Beasley, Donald E. [Mechanical Engineering Department, Clemson University, Clemson, SC 29634 (United States); Conner, Michael E. [Westinghouse Nuclear Fuel, 5801 Bluff Road, Columbia, SC 29250 (United States)

    2008-04-15

    The convective heat transfer for turbulent flow through rod bundles representative of nuclear fuel rods used in pressurized water reactors is examined. The rod bundles consist of a square array of parallel rods that are held on a constant pitch by support grids spaced axially along the rod bundle. Split-vane pair support grids, which create swirling flow in the rod bundle, as well as disc and standard support grids are investigated. Single-phase convective heat transfer coefficients are measured for flow downstream of support grids in a rod bundle. The rods are heated using direct resistance heating, and a bulk axial flow of air is used to cool the rods in the rod bundle. Air is used as the working fluid instead of water to reduce the power required to heat the rod bundle. Results indicate heat transfer enhancement for up to 10 hydraulic diameters downstream of the support grids. A general correlation is developed to predict the heat transfer development downstream of support grids. In addition, circumferential variations in heat transfer coefficients result in hot streaks that develop on the rods downstream of split-vane pair support grids.

  11. Bundling Actin Filaments From Membranes: Some Novel Players

    Directory of Open Access Journals (Sweden)

    Clément eThomas

    2012-08-01

    Full Text Available Progress in live-cell imaging of the cytoskeleton has significantly extended our knowledge about the organization and dynamics of actin filaments near the plasma membrane of plant cells. Noticeably, two populations of filamentous structures can be distinguished. On the one hand, fine actin filaments which exhibit an extremely dynamic behavior basically characterized by fast polymerization and prolific severing events, a process referred to as actin stochastic dynamics. On the other hand, thick actin bundles which are composed of several filaments and which are comparatively more stable although they constantly remodel as well. There is evidence that the actin cytoskeleton plays critical roles in trafficking and signaling at both the cell cortex and organelle periphery but the exact contribution of actin bundles remains unclear. A common view is that actin bundles provide the long-distance tracks used by myosin motors to deliver their cargo to growing regions and accordingly play a particularly important role in cell polarization. However, several studies support that actin bundles are more than simple passive highways and display multiple and dynamic roles in the regulation of many processes, such as cell elongation, polar auxin transport, stomatal and chloroplast movement, and defense against pathogens. The list of identified plant actin-bundling proteins is ever expanding, supporting that plant cells shape structurally and functionally different actin bundles. Here I review the most recently characterized actin-bundling proteins, with a particular focus on those potentially relevant to membrane trafficking and/or signaling.

  12. Nucleate boiling heat transfer on horizontal tubes in bundles

    International Nuclear Information System (INIS)

    Fujital, Y.; Ohta, H.; Hidaka, S.; Nishikawa, K.

    1986-01-01

    In order to clarify the heat transfer mechanisms of the flooded type horizontal tube bundle evaporator, heat transfer characteristics of tube bundles of experimental scale which consist both of smooth and enhanced tubes were investigated in detail. The experiments of saturated nucleate boiling were performed by using Freon 113 under pressures 0.1 to 1 MPa, and the effects of various parameters, for example, bundle arrangement, heat flux, pressure on the characteristics of an individual tube are clarified. Experimental data is reproduced well by a proposed heat transfer model in which convective heat transfer coefficients due to rising bubbles are estimated as a function of their volumetric flow rate

  13. Steady state heat transfer of helium cooled cable bundles

    International Nuclear Information System (INIS)

    Khalil, A.

    1982-01-01

    In the present study nucleate and film boiling heat transfer characteristics of horizontal conductor bundles are investigated at steady state conditions. The effect of gaps between wires, number of wires, wire position, wire size and bundle orientation on the departure from nucleate boiling and transition to film boiling is studied. For gaps close to the bubble departure diameter, the critical heat flux can approach up to 90% of the single wire value. Consequently, the maximum stable current for a given bundle can be significantly increased above the single conductor value for the same cross-sectional area. (author)

  14. On the existence of n-dimensional indecomposable vector bundles

    International Nuclear Information System (INIS)

    Tan Xiaojiang.

    1991-09-01

    Let X be an arbitrary smooth irreducible complex projective curve of genus g with g ≥ 4. In this paper we extend the existence theorem of special divisors to high dimensional indecomposable vector bundles. We give a necessary and sufficient condition on the existence of n-dimensional indecomposable vector bundles E with deg(E) = d, dimH 0 (X,E) ≥ h. We also determine under what condition the set of all such vector bundles will be finite and how many elements it contains. (author). 9 refs

  15. [Bacterial vaginosis].

    Science.gov (United States)

    Romero Herrero, Daniel; Andreu Domingo, Antonia

    2016-07-01

    Bacterial vaginosis (BV) is the main cause of vaginal dysbacteriosis in the women during the reproductive age. It is an entity in which many studies have focused for years and which is still open for discussion topics. This is due to the diversity of microorganisms that cause it and therefore, its difficult treatment. Bacterial vaginosis is probably the result of vaginal colonization by complex bacterial communities, many of them non-cultivable and with interdependent metabolism where anaerobic populations most likely play an important role in its pathogenesis. The main symptoms are an increase of vaginal discharge and the unpleasant smell of it. It can lead to serious consequences for women, such as an increased risk of contracting sexually transmitted infections including human immunodeficiency virus and upper genital tract and pregnancy complications. Gram stain is the gold standard for microbiological diagnosis of BV, but can also be diagnosed using the Amsel clinical criteria. It should not be considered a sexually transmitted disease but it is highly related to sex. Recurrence is the main problem of medical treatment. Apart from BV, there are other dysbacteriosis less characterized like aerobic vaginitis of which further studies are coming slowly but are achieving more attention and consensus among specialists. Copyright © 2016 Elsevier España, S.L.U. All rights reserved.

  16. Assembly mechanism for nuclear fuel bundles

    International Nuclear Information System (INIS)

    Long, J.W.; Flora, B.S.

    1977-01-01

    A method of securing a fuel bundle to permit easy remote disassembly is described. Fuel rods are held loosely between end plates, each end of the rods fitting into holes in the end plates. At the upper end of each fuel rod there is a spring pressing against the end plate. Tie rods are used to hold the end plates together securely. The lower end of each tie rod is screwed into the lower end plate; the upper end of each tie rod is attached to the upper end plate by means of a locking assembly described in the patent. In order to remove the upper tie plate during the disassembly process, it is necessary only to depress the tie plate against the pressure of the springs surrounding the fuel rods and then to rotate each locking sleeve on the tie rods from its locked to its unlocked position. It is then possible to remove the tie plate without disassembling the locking assembly. (LL)

  17. Development of a new bundle welding technology for CANDU fuels

    International Nuclear Information System (INIS)

    Kim, Soo Sung; Lee, D. Y.; Goo, D. S.

    2010-01-01

    The new technology of welding process for fuel bundle of CANDU nuclear fuels is considered important in respect to the soundness of weldments and the improvement of the performance of nuclear fuels during the operation in reactor. The probability of leakage of the fission products is mostly apt to occur at the weldments of fuel bundles, and it is connected directly with the safety and life prediction of the nuclear reactor in operation. The fuel bundles of CANDU nuclear fuels are welded by the electrical resistance method, connecting the endplates and endcaps with fuel rods. Therefore, the purpose of this study of the 2nd year is to select the proper welding parameters and to investigate the characteristics of the full-sized samples using the projection endplates and make some prototype samples for the endplate welding of CANDU nuclear fuels. This study will be also provide the fundamental data for the new design and fabrications of CANDU nuclear fuel bundles

  18. Improved Conjugate Gradient Bundle Adjustment of Dunhuang Wall Painting Images

    Science.gov (United States)

    Hu, K.; Huang, X.; You, H.

    2017-09-01

    Bundle adjustment with additional parameters is identified as a critical step for precise orthoimage generation and 3D reconstruction of Dunhuang wall paintings. Due to the introduction of self-calibration parameters and quasi-planar constraints, the structure of coefficient matrix of the reduced normal equation is banded-bordered, making the solving process of bundle adjustment complex. In this paper, Conjugate Gradient Bundle Adjustment (CGBA) method is deduced by calculus of variations. A preconditioning method based on improved incomplete Cholesky factorization is adopt to reduce the condition number of coefficient matrix, as well as to accelerate the iteration rate of CGBA. Both theoretical analysis and experimental results comparison with conventional method indicate that, the proposed method can effectively conquer the ill-conditioned problem of normal equation and improve the calculation efficiency of bundle adjustment with additional parameters considerably, while maintaining the actual accuracy.

  19. IMPROVED CONJUGATE GRADIENT BUNDLE ADJUSTMENT OF DUNHUANG WALL PAINTING IMAGES

    Directory of Open Access Journals (Sweden)

    K. Hu

    2017-09-01

    Full Text Available Bundle adjustment with additional parameters is identified as a critical step for precise orthoimage generation and 3D reconstruction of Dunhuang wall paintings. Due to the introduction of self-calibration parameters and quasi-planar constraints, the structure of coefficient matrix of the reduced normal equation is banded-bordered, making the solving process of bundle adjustment complex. In this paper, Conjugate Gradient Bundle Adjustment (CGBA method is deduced by calculus of variations. A preconditioning method based on improved incomplete Cholesky factorization is adopt to reduce the condition number of coefficient matrix, as well as to accelerate the iteration rate of CGBA. Both theoretical analysis and experimental results comparison with conventional method indicate that, the proposed method can effectively conquer the ill-conditioned problem of normal equation and improve the calculation efficiency of bundle adjustment with additional parameters considerably, while maintaining the actual accuracy.

  20. Some applications on tangent bundle with Kaluza-Klein metric

    Directory of Open Access Journals (Sweden)

    Murat Altunbaş

    2017-01-01

    Full Text Available In this paper, differential equations of geodesics; parallelism, incompressibility and closeness conditions of the horizontal and complete lift of the vector fields are investigated with respect to Kaluza-Klein metric on tangent bundle.

  1. Topological T-duality for torus bundles with monodromy

    Science.gov (United States)

    Baraglia, David

    2015-05-01

    We give a simplified definition of topological T-duality that applies to arbitrary torus bundles. The new definition does not involve Chern classes or spectral sequences, only gerbes and morphisms between them. All the familiar topological conditions for T-duals are shown to follow. We determine necessary and sufficient conditions for existence of a T-dual in the case of affine torus bundles. This is general enough to include all principal torus bundles as well as torus bundles with arbitrary monodromy representations. We show that isomorphisms in twisted cohomology, twisted K-theory and of Courant algebroids persist in this general setting. We also give an example where twisted K-theory groups can be computed by iterating T-duality.

  2. Design and synthesis of DNA four-helix bundles

    Energy Technology Data Exchange (ETDEWEB)

    Rangnekar, Abhijit; Gothelf, Kurt V [Department of Chemistry, Centre for DNA Nanotechnology (CDNA) and Interdisciplinary Nanoscience Center (iNANO), Aarhus University, DK-8000 Aarhus C (Denmark); LaBean, Thomas H, E-mail: kvg@chem.au.dk, E-mail: thl@cs.duke.edu [Department of Chemistry, Duke University, Durham, NC 27708 (United States)

    2011-06-10

    The field of DNA nanotechnology has evolved significantly in the past decade. Researchers have succeeded in synthesizing tile-based structures and using them to form periodic lattices in one, two and three dimensions. Origami-based structures have also been used to create nanoscale structures in two and three dimensions. Design and construction of DNA bundles with fixed circumference has added a new dimension to the field. Here we report the design and synthesis of a DNA four-helix bundle. It was found to be extremely rigid and stable. When several such bundles were assembled using appropriate sticky-ends, they formed micrometre-long filaments. However, when creation of two-dimensional sheet-like arrays of the four-helix bundles was attempted, nanoscale rings were observed instead. The exact reason behind the nanoring formation is yet to be ascertained, but it provides an exciting prospect for making programmable circular nanostructures using DNA.

  3. Design and synthesis of DNA four-helix bundles

    International Nuclear Information System (INIS)

    Rangnekar, Abhijit; Gothelf, Kurt V; LaBean, Thomas H

    2011-01-01

    The field of DNA nanotechnology has evolved significantly in the past decade. Researchers have succeeded in synthesizing tile-based structures and using them to form periodic lattices in one, two and three dimensions. Origami-based structures have also been used to create nanoscale structures in two and three dimensions. Design and construction of DNA bundles with fixed circumference has added a new dimension to the field. Here we report the design and synthesis of a DNA four-helix bundle. It was found to be extremely rigid and stable. When several such bundles were assembled using appropriate sticky-ends, they formed micrometre-long filaments. However, when creation of two-dimensional sheet-like arrays of the four-helix bundles was attempted, nanoscale rings were observed instead. The exact reason behind the nanoring formation is yet to be ascertained, but it provides an exciting prospect for making programmable circular nanostructures using DNA.

  4. Introductory lectures on fibre bundles and topology for physicists

    International Nuclear Information System (INIS)

    Thomas, G.H.

    1978-05-01

    These lectures may provide useful background material for understanding gauge theories, particularly the nonperturbative effects such as instantons and monopoles. The mathematical language of topology and fibre bundles is introduced

  5. Fuel rod bundles proposed for advanced pressure tube nuclear reactors

    International Nuclear Information System (INIS)

    Prodea, Iosif; Catana, Alexandru

    2010-01-01

    The paper aims to be a general presentation for fuel bundles to be used in Advanced Pressure Tube Nuclear Reactors (APTNR). The characteristics of such a nuclear reactor resemble those of known advanced pressure tube nuclear reactors like: Advanced CANDU Reactor (ACR TM -1000, pertaining to AECL) and Indian Advanced Heavy Water Reactor (AHWR). We have also developed a fuel bundle proposal which will be referred as ASEU-43 (Advanced Slightly Enriched Uranium with 43 rods). The ASEU-43 main design along with a few neutronic and thermalhydraulic characteristics are presented in the paper versus similar ones from INR Pitesti SEU-43 and CANDU-37 standard fuel bundles. General remarks regarding the advantages of each fuel bundle and their suitability to be burned in an APTNR reactor are also revealed. (authors)

  6. On the classification of complex vector bundles of stable rank

    Indian Academy of Sciences (India)

    , the tuples of cohomology classes on a compact, complex manifold, corresponding to the Chern classes of a complex vector bundle of stable rank. This classification becomes more effective on generalized flag manifolds, where the Lie ...

  7. Introductory lectures on fibre bundles and topology for physicists

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, G.H.

    1978-05-01

    These lectures may provide useful background material for understanding gauge theories, particularly the nonperturbative effects such as instantons and monopoles. The mathematical language of topology and fibre bundles is introduced.

  8. CANFLEX fuel bundle cross-flow endurance test (test report)

    International Nuclear Information System (INIS)

    Hong, Sung Deok; Chung, C. H.; Chang, S. K.; Kim, B. D.

    1997-04-01

    As part of the normal refuelling sequence of CANDU nuclear reactor, both new and irradiated bundles can be parked in the cross-flow region of the liner tubes. This situation occurs normally for a few minutes. The fuel bundle which is subjected to the cross-flow should be capable of withstanding the consequences of cross flow for normal periods, and maintain its mechanical integrity. The cross-flow endurance test was conducted for CANFLEX bundle, latest developed nuclear fuel, at CANDU-Hot Test Loop. The test was carried out during 4 hours at the inlet cross-flow region. After the test, the bundle successfully met all acceptance criteria after the 4 hours cross-flow test. (author). 2 refs., 3 tabs

  9. Broadband and flexible acoustic focusing by metafiber bundles

    Science.gov (United States)

    Sun, Hong-Xiang; Chen, Jia-He; Ge, Yong; Yuan, Shou-Qi; Liu, Xiao-Jun

    2018-06-01

    We report a broadband and flexible acoustic focusing through metafiber bundles in air, in which each metafiber consists of eight circular and narrow rectangular cavities. The fractional bandwidth of the acoustic focusing could reach about 0.2, which arises from the eigenmodes of the metafiber structure. Besides, owing to the flexible characteristic of the metafibers, the focus position can be manipulated by bending the metafiber bundles, and the metafiber bundles could bypass rigid scatterers inside the lens structure. More interestingly, the acoustic propagation and focusing directions can be changed by using a designed right-angled direction converter fabricated by the metafibers, and a waveform converter and a focusing lens of the cylindrical acoustic source are realized based on the metafiber bundles. The proposed focusing lens has the advantages of broad bandwidth, flexible structure, and high focusing performance, showing great potentials in versatile applications.

  10. Bundles of Norms About Teen Sex and Pregnancy.

    Science.gov (United States)

    Mollborn, Stefanie; Sennott, Christie

    2015-09-01

    Teen pregnancy is a cultural battleground in struggles over morality, education, and family. At its heart are norms about teen sex, contraception, pregnancy, and abortion. Analyzing 57 interviews with college students, we found that "bundles" of related norms shaped the messages teens hear. Teens did not think their communities encouraged teen sex or pregnancy, but normative messages differed greatly, with either moral or practical rationalizations. Teens readily identified multiple norms intended to regulate teen sex, contraception, abortion, childbearing, and the sanctioning of teen parents. Beyond influencing teens' behavior, norms shaped teenagers' public portrayals and post hoc justifications of their behavior. Although norm bundles are complex to measure, participants could summarize them succinctly. These bundles and their conflicting behavioral prescriptions create space for human agency in negotiating normative pressures. The norm bundles concept has implications for teen pregnancy prevention policies and can help revitalize social norms for understanding health behaviors. © The Author(s) 2014.

  11. Reactor physics assessment of modified 37-element CANDU fuel bundles

    International Nuclear Information System (INIS)

    Pristavu, R.; Rizoiu, A.

    2016-01-01

    Reducing the central element diameter in order to improve the total flow area of CANDU fuel bundle and redistribute the power density of all remaining elements was studied in Canada and Korea when considering the effect of aging pressure tube diametral creep. The aim of this paper is to study the modified bundle behavior using the transport codes WIMS and DRAGON. In calculations, a WIMS nuclear data library on 172 energy groups was used. 2-D transport calculations were performed with WIMS and DRAGON, leading to similar results in estimated cell parameters. Additionally, 3-D DRAGON calculations were carried on in order to evaluate the local flux distribution shift, as well as the incremental cross sections for supercells containing modified CANDU bundles and reactivity devices. The overall effect of using modified fuel bundles was meaningless for both cell and supercell parameters, thus ensuring this possibility of fuel improvement for thermal-hydraulic purposes only. (authors)

  12. Simulation of finite size effects of the fiber bundle model

    Science.gov (United States)

    Hao, Da-Peng; Tang, Gang; Xun, Zhi-Peng; Xia, Hui; Han, Kui

    2018-01-01

    In theory, the macroscopic fracture of materials should correspond with the thermodynamic limit of the fiber bundle model. However, the simulation of a fiber bundle model with an infinite size is unrealistic. To study the finite size effects of the fiber bundle model, fiber bundle models of various size are simulated in detail. The effects of system size on the constitutive behavior, critical stress, maximum avalanche size, avalanche size distribution, and increased step number of external load are explored. The simulation results imply that there is no feature size or cut size for macroscopic mechanical and statistical properties of the model. The constitutive curves near the macroscopic failure for various system size can collapse well with a simple scaling relationship. Simultaneously, the introduction of a simple extrapolation method facilitates the acquisition of more accurate simulation results in a large-limit system, which is better for comparison with theoretical results.

  13. National Partnership for Maternal Safety: Consensus Bundle on Obstetric Hemorrhage.

    Science.gov (United States)

    Main, Elliott K; Goffman, Dena; Scavone, Barbara M; Low, Lisa Kane; Bingham, Debra; Fontaine, Patricia L; Gorlin, Jed B; Lagrew, David C; Levy, Barbara S

    2015-07-01

    Hemorrhage is the most frequent cause of severe maternal morbidity and preventable maternal mortality and therefore is an ideal topic for the initial national maternity patient safety bundle. These safety bundles outline critical clinical practices that should be implemented in every maternity unit. They are developed by multidisciplinary work groups of the National Partnership for Maternal Safety under the guidance of the Council on Patient Safety in Women's Health Care. The safety bundle is organized into four domains: Readiness, Recognition and Prevention, Response, and Reporting and System Learning. Although the bundle components may be adapted to meet the resources available in individual facilities, standardization within an institution is strongly encouraged. References contain sample resources and "Potential Best Practices" to assist with implementation.

  14. National Partnership for Maternal Safety Consensus Bundle on Obstetric Hemorrhage.

    Science.gov (United States)

    Main, Elliott K; Goffman, Dena; Scavone, Barbara M; Low, Lisa Kane; Bingham, Debra; Fontaine, Patricia L; Gorlin, Jed B; Lagrew, David C; Levy, Barbara S

    2015-01-01

    Hemorrhage is the most frequent cause of severe maternal morbidity and preventable maternal mortality and therefore is an ideal topic for the initial national maternity patient safety bundle. These safety bundles outline critical clinical practices that should be implemented in every maternity unit. They are developed by multidisciplinary work groups of the National Partnership for Maternal Safety under the guidance of the Council on Patient Safety in Women's Health Care. The safety bundle is organized into 4 domains: Readiness, Recognition and Prevention, Response, and Reporting and Systems Learning. Although the bundle components may be adapted to meet the resources available in individual facilities, standardization within an institution is strongly encouraged. References contain sample resources and "Potential Best Practices" to assist with implementation. © 2015 by the American College of Obstetricians and Gynecologists.

  15. CANFLEX fuel bundle cross-flow endurance test (test report)

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Sung Deok; Chung, C. H.; Chang, S. K.; Kim, B. D.

    1997-04-01

    As part of the normal refuelling sequence of CANDU nuclear reactor, both new and irradiated bundles can be parked in the cross-flow region of the liner tubes. This situation occurs normally for a few minutes. The fuel bundle which is subjected to the cross-flow should be capable of withstanding the consequences of cross flow for normal periods, and maintain its mechanical integrity. The cross-flow endurance test was conducted for CANFLEX bundle, latest developed nuclear fuel, at CANDU-Hot Test Loop. The test was carried out during 4 hours at the inlet cross-flow region. After the test, the bundle successfully met all acceptance criteria after the 4 hours cross-flow test. (author). 2 refs., 3 tabs.

  16. Interactive hypermedia training manual for spent-fuel bundle counters

    International Nuclear Information System (INIS)

    Basso, R.A.

    1990-07-01

    Spent-fuel bundle counters, developed by the Canadian Safeguards Support Program for the International Atomic Energy Agency, provide a secure and independent means of counting the number of irradiated fuel bundles discharged into the fuel storage bays at CANDU nuclear power stations. Paper manuals have been traditionally used to familiarize IAEA inspectors with the operation, maintenance and extensive reporting capabilities of the bundle counters. To further assist inspectors, an interactive training manual has been developed on an Apple Macintosh computer using hypermedia software. The manual uses interactive animation and sound, in conjunction with the traditional text and graphics, to simulate the underlying operation and logic of the bundle counters. This paper presents the key features of the interactive manual and highlights the advantages of this new technology for training

  17. Investigations with diagnostic fuel rod bundles on Rheinsberg NPP

    International Nuclear Information System (INIS)

    Krauze, F.; Rudolf, G.; Shajfler, V.; Tsimke, K.

    1982-01-01

    In 70MW pressurized water reactor of Rheinsberg NPP diagnostic fuel rod bundles have been installed: first of DK 1 type and then of DK 2 advanced type. Three rounds of measurement were run with DK 1 bundle and one with DK 2. The diagnostic bundles are equiped with various sensors for temperature, pressure, neutron flux and mechanical stress measurements as well as with special flow rate control system which allows to reach coolant boiling within the bundle. Qualitative and quantitative description of the sensors performance during reactor operation is given. The presented experimental results are connected with: 1) working capability of the measuring devices and their calibration; 2) throttling and boiling in two regimes: a) stationary and non-stationary flow rate throbgh DK during stationary reactor operation; b) various constant levels of flow rate through DK during non-stationary reactor operation regime [ru

  18. Absorber rod bundle actuator in a pressurized water nuclear reactor

    International Nuclear Information System (INIS)

    Martin, J.; Peletan, R.

    1984-01-01

    The invention concerns an absorber rod bundle actuator in a pressurized water reactor with spectral shift control. The device comprises two coaxial control bars. The inner bar is integral with the absorber rod bundle; it has an enlarged zone which acts as a proton under pressure difference across an annular seal which can be radially expanded, the pressure difference allowing to the absorber rod bundles actuating on the piston. When a pressure difference is applied, the seal expands radially by a sufficient amount to make sealing contact with the zone of larger diameter in the outer bar. The invention applies more particularly to reactors with spectral shift control using bundles of fertile rods [fr

  19. CHF prediction in rod bundles using round tube data

    Energy Technology Data Exchange (ETDEWEB)

    Souza, Wallen F.; Veloso, Maria A.F.; Pereira, Cláubia; Costa, Antonella L., E-mail: wallenfds@yahoo.com.br, E-mail: mdora@nuclear.ufmg.br [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Departamento de Engenharia Nuclear

    2017-07-01

    The present work concerns the use of 1995 CHF table for uniformly heated round tubes, developed jointly by Canadian and Russian researchers, for the prediction of critical heat fluxes in rod bundles geometries. Comparisons between measured and calculated critical heat fluxes indicate that this table could be applied to rod bundles provided that a suitable correction factor is employed. The tolerance limits associated with the departure from nucleate boiling ratio (DNBR) are evaluated by using statistical analysis. (author)

  20. On Chern ratios for surfaces with ample cotangent bundle

    Directory of Open Access Journals (Sweden)

    Denis Conduché

    2006-10-01

    Full Text Available In this paper we study the problem of density in (1, 3 for the Chern ratio of surfaces with ample cotangent bundle. In particular we prove density in (1, 2 by constructing a family of complete intersection surfaces in a product of varieties with big cotangent bundle. We also analyse the case of complete intersections in a product of curves of genus at least 2.

  1. Bundle Pricing Decisions for Fresh Products with Quality Deterioration

    OpenAIRE

    Fang, Yan; Jiang, Yiping; Han, Xingxing

    2018-01-01

    How to sell fresh products quickly to decrease the storage cost and to meet customer quality requirement is of vital importance in the food supply chain. Bundling fresh products is an efficient strategy to promote sales and reduce storage pressure of retailers. In this paper, we consider the bundle pricing decisions for homogeneous fresh products with quality deterioration. The value of fresh products with quality deterioration is approximated as an exponential function based on which custome...

  2. Design and verification of the 'GURI 01' bundle model

    International Nuclear Information System (INIS)

    Benito, G.D.

    1990-01-01

    This work presents a general description of the 'GURI 01' bundle model, designed by INVAP S.E., under international radioactive material transportation regulations, as a B(U) type bundle for international transportation up to a maximum of 350000 Ci of Co60. Moreover, the methodologies used and the results obtained from the structural evaluation of the mechanic essay and from the evaluation of the thermal behaviour under normal or accident conditions are briefly discussed. (Author) [es

  3. Fuel temperature characteristics of the 37-element and CANFLEX fuel bundle

    International Nuclear Information System (INIS)

    Bae, Jun Ho; Rho, Gyu Hong; Park, Joo Hwan

    2009-10-01

    This report describes the fuel temperature characteristics of CANFLEX fuel bundles and 37-element fuel bundles for a different burnup of fuel. The program was consisted for seeking the fuel temperature of fuel bundles of CANFLEX fuel bundles and 37-element fuel bundles by using the method in NUCIRC. Fuel temperature has an increasing pattern with the burnup of fuel for CANFLEX fuel bundles and 37-element fuel bundles. For all the case of burnup, the fuel temperature of CANFLEX fuel bundles has a lower value than that of 37-element fuel bundles. Especially, for the high power channel, the CANFLEX fuel bundles show a lower fuel temperature as much as about 75 degree, and the core averaged fuel temperature has a lower fuel temperature of about 50 degree than that of 37-element fuel bundles. The lower fuel temperature of CANFLEX fuel bundles is expected to enhance the safety by reducing the fuel temperature coefficient. Finally, for each burnup of CANFLEX fuel bundles and 37-element fuel bundles, the equation was present for predicting the fuel temperature of a bundle in terms of a coolant temperature and bundle power

  4. Bacterial mitosis

    DEFF Research Database (Denmark)

    Møller-Jensen, Jakob; Borch, Jonas; Dam, Mette

    2003-01-01

    Bacterial DNA segregation takes place in an active and ordered fashion. In the case of Escherichia coli plasmid R1, the partitioning system (par) separates paired plasmid copies and moves them to opposite cell poles. Here we address the mechanism by which the three components of the R1 par system...... act together to generate the force required for plasmid movement during segregation. ParR protein binds cooperatively to the centromeric parC DNA region, thereby forming a complex that interacts with the filament-forming actin-like ParM protein in an ATP-dependent manner, suggesting that plasmid...

  5. Filament bundle location influence on coupling losses in superconducting composites

    International Nuclear Information System (INIS)

    Ito, Daisuke; Koizumi, Misao; Hamajima, Takataro; Nakane, Fumoto.

    1983-01-01

    The ac losses in multifilamentary superconducting composites with different superconducting filament bundle positions have been measured using the magnetization method in order to reveal the relation between filament bundle position and coupling losses. Loss components depending on dB/dt in a mixed matrix superconducting composite, whose filament bundle is located in a central region surrounded by an outer stabilizing copper sheath, has been compared with another superconducting composite whose stabilizing copper is located in a central region surrounded by an outer filament bundle. In both conductors, key parameters, such as filament twistpitch, wire diameter and amount of copper stabilizer, were almost the same. Applied magnetic field is 2 Tesla with 0.05-2 Tesla/sec field change rate. Experimental results indicate that coupling losses between filaments in the composite with the filament bundle located in the central region is smaller than the composite with the filament bundle located in the outer region. A similar conclusion was reached theoretically by B. Truck. Coupling loss values obtained by the experiment show good agreement with calculated values with the equations proposed by B. Truck. It is also pointed out that a copper stabilizer, divided by the CuNi barrier into small regions, like a honeycomb, causes anomalous increasing in the copper resistivity due to Ni diffusion during heat treatment. (author)

  6. Experimental investigation of the coolability of blocked hexagonal bundles

    Energy Technology Data Exchange (ETDEWEB)

    Hózer, Zoltán, E-mail: zoltan.hozer@energia.mta.hu; Nagy, Imre; Kunstár, Mihály; Szabó, Péter; Vér, Nóra; Farkas, Róbert; Trosztel, István; Vimi, András

    2017-06-15

    Highlights: • Experiments were performed with electrically heated hexagonal fuel bundles. • Coolability of ballooned VVER-440 type bundle was confirmed up to high blockage rate. • Pellet relocation effect causes delay in the cool-down of the bundle. • The bypass line does not prevent the reflood of ballooned fuel rods. - Abstract: The CODEX-COOL experimental series was carried out in order to evaluate the effect of ballooning and pellet relocation in hexagonal bundles on the coolability of fuel rods after a LOCA event. The effects of blockage geometry, coolant flowrate, initial temperature and axial profile were investigated. The experimental results confirmed that a VVER bundle up to 80% blockage rate remains coolable after a LOCA event under design basis conditions. The ballooned section creates some obstacles for the cooling water during reflood of the bundle, but this effect causes only a short delay in the cooling down of the hot fuel rods. The accumulation of fuel pellet debris in the ballooned volume results in a local power peak, which leads to further slowing down of quench front.

  7. The Comparison Analysis of Thermalhydraulic Behavior Between A Reference 37-element Bundle and A Modified 37-element Bundle

    International Nuclear Information System (INIS)

    Ryu, Eui-Seung; You, Sung-Chang

    2014-01-01

    As pressure tube diameter creep increase, the coolant flows through some of the interior subchannels of the fuel bundle are reduced and consequently reduces the Critical Heat Flux (CHF). For this reason, Canadian Utilities have performed the project that developing the new fuel design (modified 37-element bundle) to increase critical heat flux. The modified 37-element (37M) bundle has the same overall geometry as the reference 37-element (37R) bundle that is using in the Wolsong units now but the center element diameter has been reduced from 13.06mm to 11.5mm. The reduction in center element diameter of the 37M bundle design increase the flow of center areas to improve the cooling and thus to enhance CHF. The CHF experiments with 37M bundle string simulator in un-crept and crept (3.3%, 5.1% peak creep) flow channels were completed at Stern Laboratories in 2008. A substantially large increase in dryout-power was observed for the 37M bundle compared to the 37R bundle, particularly in the 5.1% crept channel. As a result of the experiments, Ontario Power Generation (OPG) and Bruce Power (BP) have increased the operational margin with this CHF correlation and has fully refueled the 37M fuel on some units or almost done on the other units. KHNP also has performed the project to refuel the 37M bundle which is the same design with OPG and BP recently. This paper summarizes the comparison assessment of Thermalhydraulic (T/H) behavior for 37M bundle and 37R bundle with their own correlations and geometry parameters. This analysis performed with the thermal hydraulic code (NUCIRC) and the site measured data at the Wolsong Unit2. Tests to evaluate the CHF performance with the 37M fuel bundle have been conducted in 2008 using the un-crept, 3.3% crept and 5.1% crept flow channels in the CHF Test facility at Stern Laboratories. In addition pressure drop tests have been performed at the same time. The changes of geometry from 37R bundle to 37M bundle reduced the center element

  8. Curcumin Reduces the Motility of Salmonella enterica Serovar Typhimurium by Binding to the Flagella, Thereby Leading to Flagellar Fragility and Shedding

    Science.gov (United States)

    Balakrishnan, Arjun; Negi, Vidya Devi; Sakorey, Deepika; Chandra, Nagasuma

    2016-01-01

    ABSTRACT One of the important virulence properties of the pathogen is its ability to travel to a favorable environment, cross the viscous mucus barrier (intestinal barrier for enteric pathogens), and reach the epithelia to initiate pathogenesis with the help of an appendage, like flagella. Nonetheless, flagella can act as an “Achilles heel,” revealing the pathogen's presence to the host through the stimulation of innate and adaptive immune responses. We assessed whether curcumin, a dietary polyphenol, could alter the motility of Salmonella, a foodborne pathogen. It reduced the motility of Salmonella enterica serovar Typhimurium by shortening the length of the flagellar filament (from ∼8 μm to ∼5 μm) and decreasing its density (4 or 5 flagella/bacterium instead of 8 or 9 flagella/bacterium). Upon curcumin treatment, the percentage of flagellated bacteria declined from ∼84% to 59%. However, no change was detected in the expression of the flagellin gene and protein. A fluorescence binding assay demonstrated binding of curcumin to the flagellar filament. This might make the filament fragile, breaking it into smaller fragments. Computational analysis predicted the binding of curcumin, its analogues, and its degraded products to a flagellin molecule at an interface between domains D1 and D2. Site-directed mutagenesis and a fluorescence binding assay confirmed the binding of curcumin to flagellin at residues ASN120, ASP123, ASN163, SER164, ASN173, and GLN175. IMPORTANCE This work, to our knowledge the first report of its kind, examines how curcumin targets flagellar density and affects the pathogenesis of bacteria. We found that curcumin does not affect any of the flagellar synthesis genes. Instead, it binds to the flagellum and makes it fragile. It increases the torsional stress on the flagellar filament that then breaks, leaving fewer flagella around the bacteria. Flagella, which are crucial ligands for Toll-like receptor 5, are some of the most important

  9. Tuning Bacterial Hydrodynamics with Magnetic Fields: A Path to Bacterial Robotics

    Science.gov (United States)

    Pierce, Christopher; Mumper, Eric; Brangham, Jack; Wijesinghe, Hiran; Lower, Stephen; Lower, Brian; Yang, Fengyuan; Sooryakumar, Ratnasingham

    Magnetotactic Bacteria (MTB) are a group of motile prokaryotes that synthesize chains of lipid-bound, magnetic nano-particles. In this study, the innate magnetism of these flagellated swimmers is exploited to explore their hydrodynamics near confining surfaces, using the magnetic field as a tuning parameter. With weak (Gauss), uniform, external, magnetic ?elds and the field gradients arising from micro-magnetic surface patterns, the relative strength of hydrodynamic, magnetic and ?agellar force components is tuned through magnetic control of the bacteria's orientation and position. In addition to direct measurement of several hydrodynamic quantities related to the motility of individual cells, their tunable dynamics reveal a number of novel, highly controllable swimming behaviors with potential value in micro-robotics applications. Specifically, the experiments permit the MTB cells to be directed along parallel or divergent trajectories, suppress their flagellar forces through magnetic means, and induce transitions between planar, circulating trajectories and drifting, vertically oriented ``top-like'' motion. The implications of the work for fundamental hydrodynamics research as well as bacterially driven robotics applications will be discussed.

  10. SCADOP: Phenomenological modeling of dryout in nuclear fuel rod bundles

    Energy Technology Data Exchange (ETDEWEB)

    Dasgupta, Arnab, E-mail: arnie@barc.gov.in; Chandraker, D.K., E-mail: dineshkc@barc.gov.in; Vijayan, P.K., E-mail: vijayanp@barc.gov.in

    2015-11-15

    Highlights: • Phenomenological model for annular flow dryout is presented. • The model evaluates initial entrained fraction using a new methodology. • The history effect in annular flow is predicted and validated. • Rod bundle dryout is predicted using subchannel methodology. • Model is validated against experimental dryout data in tubes and rod bundles. - Abstract: Analysis and prediction of dryout is of important consequence to safety of nuclear fuel clusters of boiling water type of reactors. Traditionally, experimental correlations are used for dryout predictions. Since these correlations are based on operating parameters and do not aim to model the underlying phenomena, there has been a proliferation of the correlations, each catering to some specific bundle geometry under a specific set of operating conditions. Moreover, such experiments are extremely costly. In general, changes in tested bundle geometry for improvement in thermal-hydraulic performance would require re-experimentation. Understanding and modeling the basic processes leading to dryout in flow boiling thus has great incentive. Such a model has the ability to predict dryout in any rod bundle geometry, unlike the operating parameter based correlation approach. Thus more informed experiments can be carried out. A good model can, reduce the number of experiments required during the iterations in bundle design. In this paper, a phenomenological model as indicated above is presented. The model incorporates a new methodology to estimate the Initial Entrained Fraction (IEF), i.e., entrained fraction at the onset of annular flow. The incorporation of this new methodology is important since IEF is often assumed ad-hoc and sometimes also used as a parameter to tune the model predictions to experimental data. It is highlighted that IEF may be low under certain conditions against the general perception of a high IEF due to influence of churn flow. It is shown that the same phenomenological model is

  11. Transcriptional analysis of the MrpJ network: modulation of diverse virulence-associated genes and direct regulation of mrp fimbrial and flhDC flagellar operons in Proteus mirabilis.

    Science.gov (United States)

    Bode, Nadine J; Debnath, Irina; Kuan, Lisa; Schulfer, Anjelique; Ty, Maureen; Pearson, Melanie M

    2015-06-01

    The enteric bacterium Proteus mirabilis is associated with a significant number of catheter-associated urinary tract infections (UTIs). Strict regulation of the antagonistic processes of adhesion and motility, mediated by fimbriae and flagella, respectively, is essential for disease progression. Previously, the transcriptional regulator MrpJ, which is encoded by the mrp fimbrial operon, has been shown to repress both swimming and swarming motility. Here we show that MrpJ affects an array of cellular processes beyond adherence and motility. Microarray analysis found that expression of mrpJ mimicking levels observed during UTIs leads to differential expression of 217 genes related to, among other functions, bacterial virulence, type VI secretion, and metabolism. We probed the molecular mechanism of transcriptional regulation by MrpJ using transcriptional reporters and chromatin immunoprecipitation (ChIP). Binding of MrpJ to two virulence-associated target gene promoters, the promoters of the flagellar master regulator flhDC and mrp itself, appears to be affected by the condensation state of the native chromosome, although both targets share a direct MrpJ binding site proximal to the transcriptional start. Furthermore, an mrpJ deletion mutant colonized the bladders of mice at significantly lower levels in a transurethral model of infection. Additionally, we observed that mrpJ is widely conserved in a collection of recent clinical isolates. Altogether, these findings support a role of MrpJ as a global regulator of P. mirabilis virulence. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  12. The role of complementarity and partner brand price level in new product introduction strategy using bundle offers: A study on the quality perception of bundle components.

    OpenAIRE

    Khandeparkar, Kapil

    2014-01-01

    New products are often bundled with strong brands as an introduction strategy. This study helps to understand the scenarios which will be most beneficial to both the products in the bundle. The enhancement effect and categorisation theory is used to explain that the new product's quality perception is higher when it is bundled with a strong brand of a higher price and this effect is moderated by the complementarity of the bundled components. Also, the quality perception of the strong brand is...

  13. Bacterial Ecology

    DEFF Research Database (Denmark)

    Fenchel, Tom

    2011-01-01

    compounds these must first be undergo extracellular hydrolysis. Bacteria have a great diversity with respect to types of metabolism that far exceeds the metabolic repertoire of eukaryotic organisms. Bacteria play a fundamental role in the biosphere and certain key processes such as, for example......, the production and oxidation of methane, nitrate reduction and fixation of atmospheric nitrogen are exclusively carried out by different groups of bacteria. Some bacterial species – ‘extremophiles’ – thrive in extreme environments in which no eukaryotic organisms can survive with respect to temperature, salinity...... biogeochemical processes are carried exclusively by bacteria. * Bacteria play an important role in all types of habitats including some that cannot support eukaryotic life....

  14. Bacterial Actins.

    Science.gov (United States)

    Izoré, Thierry; van den Ent, Fusinita

    2017-01-01

    A diverse set of protein polymers, structurally related to actin filaments contributes to the organization of bacterial cells as cytomotive or cytoskeletal filaments. This chapter describes actin homologs encoded by bacterial chromosomes. MamK filaments, unique to magnetotactic bacteria, help establishing magnetic biological compasses by interacting with magnetosomes. Magnetosomes are intracellular membrane invaginations containing biomineralized crystals of iron oxide that are positioned by MamK along the long-axis of the cell. FtsA is widespread across bacteria and it is one of the earliest components of the divisome to arrive at midcell, where it anchors the cell division machinery to the membrane. FtsA binds directly to FtsZ filaments and to the membrane through its C-terminus. FtsA shows altered domain architecture when compared to the canonical actin fold. FtsA's subdomain 1C replaces subdomain 1B of other members of the actin family and is located on the opposite side of the molecule. Nevertheless, when FtsA assembles into protofilaments, the protofilament structure is preserved, as subdomain 1C replaces subdomain IB of the following subunit in a canonical actin filament. MreB has an essential role in shape-maintenance of most rod-shaped bacteria. Unusually, MreB filaments assemble from two protofilaments in a flat and antiparallel arrangement. This non-polar architecture implies that both MreB filament ends are structurally identical. MreB filaments bind directly to membranes where they interact with both cytosolic and membrane proteins, thereby forming a key component of the elongasome. MreB filaments in cells are short and dynamic, moving around the long axis of rod-shaped cells, sensing curvature of the membrane and being implicated in peptidoglycan synthesis.

  15. The Sensor Kinase GacS Negatively Regulates Flagellar Formation and Motility in a Biocontrol Bacterium, Pseudomonas chlororaphis O6

    Directory of Open Access Journals (Sweden)

    Ji Soo Kim

    2014-06-01

    Full Text Available The GacS/GacA two component system regulates various traits related to the biocontrol potential of plant-associated pseudomonads. The role of the sensor kinase, GacS, differs between strains in regulation of motility. In this study, we determined how a gacS mutation changed cell morphology and motility in Pseudomonas chlororaphis O6. The gacS mutant cells were elongated in stationary-phase compared to the wild type and the complemented gacS mutant, but cells did not differ in length in logarithmic phase. The gacS mutant had a two-fold increase in the number of flagella compared with the wild type strain; flagella number was restored to that of the wild type in the complemented gacS mutant. The more highly flagellated gacS mutant cells had greater swimming motilities than that of the wild type strain. Enhanced flagella formation in the gacS mutant correlated with increased expression of three genes, fleQ, fliQ and flhF, involved in flagellar formation. Expression of these genes in the complemented gacS mutant was similar to that of the wild type. These findings show that this root-colonizing pseudomonad adjusts flagella formation and cell morphology in stationary-phase using GacS as a major regulator.

  16. Zernike phase contrast cryo-electron tomography of sodium-driven flagellar hook-basal bodies from Vibrio alginolyticus.

    Science.gov (United States)

    Hosogi, Naoki; Shigematsu, Hideki; Terashima, Hiroyuki; Homma, Michio; Nagayama, Kuniaki

    2011-01-01

    Vibrio alginolyticus use flagella to swim. A flagellum consists of a filament, hook and basal body. The basal body is made up of a rod and several ring structures. This study investigates the structure of the T ring which is a unique component of the V. alginolyticus sodium ion-driven flagellar basal body. Using Zernike phase contrast (ZPC) cryo-electron tomography, we compared the 3D structures of purified hook-basal bodies (HBB) from a wild-type strain (KK148) and a deletion mutant lacking MotX and MotY (TH3), which are thought to form the T ring. ZPC images of HBBs had highly improved signal-to-noise ratio compared to conventional phase contrast images. We observed the outline of the HBBs from strains KK148 and TH3, and the TH3 mutant was missing its T ring. In the wild-type strain, the T ring was beneath the LP ring and seemed to form a ring shape with diameter of 32 nm. Copyright © 2010 Elsevier Inc. All rights reserved.

  17. Histones bundle F-actin filaments and affect actin structure.

    Directory of Open Access Journals (Sweden)

    Edna Blotnick

    Full Text Available Histones are small polycationic proteins complexed with DNA located in the cell nucleus. Upon apoptosis they are secreted from the cells and react with extracellular polyanionic compounds. Actin which is a polyanionic protein, is also secreted from necrotic cells and interacts with histones. We showed that both histone mixture (histone type III and the recombinant H2A histone bundles F-actin, increases the viscosity of the F-actin containing solution and polymerizes G-actin. The histone-actin bundles are relatively insensitive to increase of ionic strength, unlike other polycation, histatin, lysozyme, spermine and LL-37 induced F-actin bundles. The histone-actin bundles dissociate completely only in the presence of 300-400 mM NaCl. DNA, which competes with F-actin for histones, disassembles histone induced actin bundles. DNase1, which depolymerizes F- to G-actin, actively unbundles the H2A histone induced but slightly affects the histone mixture induced actin bundles. Cofilin decreases the amount of F-actin sedimented by low speed centrifugation, increases light scattering and viscosity of F-actin-histone mixture containing solutions and forms star like superstructures by copolymerizing G-actin with H2A histone. The results indicate that histones are tightly attached to F-actin by strong electrostatic and hydrophobic forces. Since both histones and F-actin are present in the sputum of patients with cystic fibrosis, therefore, the formation of the stable histone-actin bundles can contribute to the pathology of this disease by increasing the viscosity of the sputum. The actin-histone interaction in the nucleus might affect gene expression.

  18. Histones bundle F-actin filaments and affect actin structure.

    Science.gov (United States)

    Blotnick, Edna; Sol, Asaf; Muhlrad, Andras

    2017-01-01

    Histones are small polycationic proteins complexed with DNA located in the cell nucleus. Upon apoptosis they are secreted from the cells and react with extracellular polyanionic compounds. Actin which is a polyanionic protein, is also secreted from necrotic cells and interacts with histones. We showed that both histone mixture (histone type III) and the recombinant H2A histone bundles F-actin, increases the viscosity of the F-actin containing solution and polymerizes G-actin. The histone-actin bundles are relatively insensitive to increase of ionic strength, unlike other polycation, histatin, lysozyme, spermine and LL-37 induced F-actin bundles. The histone-actin bundles dissociate completely only in the presence of 300-400 mM NaCl. DNA, which competes with F-actin for histones, disassembles histone induced actin bundles. DNase1, which depolymerizes F- to G-actin, actively unbundles the H2A histone induced but slightly affects the histone mixture induced actin bundles. Cofilin decreases the amount of F-actin sedimented by low speed centrifugation, increases light scattering and viscosity of F-actin-histone mixture containing solutions and forms star like superstructures by copolymerizing G-actin with H2A histone. The results indicate that histones are tightly attached to F-actin by strong electrostatic and hydrophobic forces. Since both histones and F-actin are present in the sputum of patients with cystic fibrosis, therefore, the formation of the stable histone-actin bundles can contribute to the pathology of this disease by increasing the viscosity of the sputum. The actin-histone interaction in the nucleus might affect gene expression.

  19. Verification of the FBR fuel bundle-duct interaction analysis code BAMBOO by the out-of-pile bundle compression test with large diameter pins

    Science.gov (United States)

    Uwaba, Tomoyuki; Ito, Masahiro; Nemoto, Junichi; Ichikawa, Shoichi; Katsuyama, Kozo

    2014-09-01

    The BAMBOO computer code was verified by results for the out-of-pile bundle compression test with large diameter pin bundle deformation under the bundle-duct interaction (BDI) condition. The pin diameters of the examined test bundles were 8.5 mm and 10.4 mm, which are targeted as preliminary fuel pin diameters for the upgraded core of the prototype fast breeder reactor (FBR) and for demonstration and commercial FBRs studied in the FaCT project. In the bundle compression test, bundle cross-sectional views were obtained from X-ray computer tomography (CT) images and local parameters of bundle deformation such as pin-to-duct and pin-to-pin clearances were measured by CT image analyses. In the verification, calculation results of bundle deformation obtained by the BAMBOO code analyses were compared with the experimental results from the CT image analyses. The comparison showed that the BAMBOO code reasonably predicts deformation of large diameter pin bundles under the BDI condition by assuming that pin bowing and cladding oval distortion are the major deformation mechanisms, the same as in the case of small diameter pin bundles. In addition, the BAMBOO analysis results confirmed that cladding oval distortion effectively suppresses BDI in large diameter pin bundles as well as in small diameter pin bundles.

  20. Design concept and testing of an in-bundle gamma densitometer for subchannel void fraction measurements in the THTF electrically heated rod bundle

    International Nuclear Information System (INIS)

    Felde, D.K.

    1982-04-01

    A design concept is presented for an in-bundle gamma densitometer system for measurement of subchannel average fluid density and void fraction in rod or tube bundles. This report describes (1) the application of the design concept to the Thermal-Hydraulic Test Facility (THTF) electrically heated rod bundle; and (2) results from tests conducted in the THTF

  1. Evaluation of bundle duct interaction by out-of-pile compression test of FBR fuel pin bundles

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, Kosuke; Yamamoto, Yuji; Nagamine, Tsuyoshi; Maeda, Koji [Japan Nuclear Cycle Development Inst., Oarai, Ibaraki (Japan). Oarai Engineering Center

    2001-06-01

    Bundle duct interaction (BDI) caused by expansion of fuel pin bundle is a main factor to limit the fuel lifetime. Therefore, it is important for the design of fast reactor fuel assembly to understand the fuel pin deformation behavior under BDI condition. In order to understand the fuel pin deformation behavior under BDI condition, out-of-pile compression tests were conducted for FBR fuel pin bundle by use of X-ray CT equipment. In these compression tests, two kinds of fuel pin bundles were conducted. One was the fuel pin bundle with the short wire-pitch and the other was the fuel pin bundle with the short wire-pitch and large diameter claddings. The general discussions were also performed based on the results of out-of-pile compression tests obtained by use of X-ray CT equipment in the previous work. Following results were obtained. 1) The occurrence of the pin-to-duct contact depends on the wire-pitch. In the fuel pin bundle with large wire-pitch, the pin-to-duct contact occurred at the early stage of BDI. The reason of this result is due to the low bowing rigidity of the fuel pins with long wire-pitch. 2) The value of the ovalation stiffness strongly depends on the geometry of cladding (diameter, thickness) and especially on wire-pitch. This result in this work revealed that the occurrence of the pin-to-duct contact depends on the value of the ovalation stiffness. 3) The occurrence of wire dispersion and dispersive displacement of pins depends on the wire-pitch strongly. In the fuel pin bundle with the long wire-pitch, the occurrence of the above-mentioned suppression mechanism to BDI is remarkable. 4) The suppression mechanism to BDI of the fuel pin bundle with the long wire-pitch is elastic oval deformation of cladding, wire dispersion and dispersive displacement of pins. On the other hand, the elastic and plastic oval deformation of cladding is the major suppression mechanism to BDI in the fuel pin bundle with the short wire-pitch. 5) The appearance of

  2. Brachytherapy radiation doses to the neurovascular bundles

    International Nuclear Information System (INIS)

    Di Biase, Steven J.; Wallner, Kent; Tralins, Kevin; Sutlief, Steven

    2000-01-01

    Purpose: To investigate the role of radiation dose to the neurovascular bundles (NVB) in brachytherapy-related impotence. Methods and Materials: Fourteen Pd-103 or I-125 implant patients were studied. For patients treated with implant alone, the prostate and margin (clinical target volume [CTV]) received a prescription dose of 144 Gy for I-125 or 115 Gy for Pd-103. Two patients received Pd-103 (90 Gy) with 46 Gy supplemental external beam radiation (EBRT). Axial CT images were acquired 2 to 4 hours postoperatively for postimplant dosimetry. Because the NVBs cannot be visualized on CT, NVB calculation points were determined according to previously published anatomic descriptions. Bilateral NVB points were considered to lie posterior-laterally, approximately 2 mm from the prostatic capsule. NVB doses were recorded bilaterally, at 0.5-cm intervals from the prostatic base. Results: For Pd-103, the average NVB doses ranged from 150 Gy to 260 Gy, or 130% to 226% of the prescription dose. For I-125, the average NVB dose ranged from 200 Gy to 325 Gy, or 140% to 225% of the prescription dose. These was no consistent relationship between the NVB dose and the distance from the prostatic base. To examine the possible effect of minor deviations of our calculation points from the true NVB location, we performed NVB calculations at points 2 mm medial or lateral from the NVB calculation point in 8 patients. Doses at these alternate calculation points were comparable, although there was greater variability with small changes in the calculation point if sources were located outside the capsule, near the NVB calculation point. Three patients who developed early postimplant impotence had maximal NVB doses that far exceeded the average values. Conclusions: In the next few years, we hope to clarify the role of high NVB radiation doses on potency, by correlating NVB dose calculations with a large number of patients enrolled in an ongoing I-125 versus Pd-103 trial for early-stage patients

  3. Aerosol retention in the flooded steam generator bundle during SGTR

    International Nuclear Information System (INIS)

    Lind, Terttaliisa; Dehbi, Abdel; Guentay, Salih

    2011-01-01

    Research highlights: → High retention of aerosol particles in a steam generator bundle flooded with water. → Increasing particle inertia, i.e., particle size and velocity, increases retention. → Much higher retention of aerosol particles in the steam generator bundle flooded with water than in a dry bundle. → Much higher retention of aerosol particles in the steam generator bundle than in a bare pool. → Bare pool models have to be adapted to be applicable for flooded bundles. - Abstract: A steam generator tube rupture in a pressurized water reactor may cause accidental release of radioactive particles into the environment. Its specific significance is in its potential to bypass the containment thereby providing a direct pathway of the radioactivity from the primary circuit to the environment. Under certain severe accident scenarios, the steam generator bundle may be flooded with water. In addition, some severe accident management procedures are designed to minimize the release of radioactivity into the environment by flooding the defective steam generator secondary side with water when the steam generator has dried out. To extend our understanding of the particle retention phenomena in the flooded steam generator bundle, tests were conducted in the ARTIST and ARTIST II programs to determine the effect of different parameters on particle retention. The effects of particle type (spherical or agglomerate), particle size, gas mass flow rate, and the break submergence on particle retention were investigated. Results can be summarized as follows: increasing particle inertia was found to increase retention in the flooded bundle. Particle shape, i.e., agglomerate or spherical structure, did not affect retention significantly. Even with a very low submergence, 0.3 m above the tube break, significant aerosol retention took place underlining the importance of the jet-bundle interactions close to the tube break. Droplets were entrained from the water surface with

  4. An in vitro biomechanical comparison of anterior cruciate ligament reconstruction: single bundle versus anatomical double bundle techniques

    Directory of Open Access Journals (Sweden)

    Sandra Umeda Sasaki

    2008-01-01

    Full Text Available INTRODUCTION: Anterior cruciate ligament ruptures are frequent, especially in sports. Surgical reconstruction with autologous grafts is widely employed in the international literature. Controversies remain with respect to technique variations as continuous research for improvement takes place. One of these variations is the anatomical double bundle technique, which is performed instead of the conventional single bundle technique. More recently, there has been a tendency towards positioning the two bundles through double bone tunnels in the femur and tibia (anatomical reconstruction. OBJECTIVES: To compare, through biomechanical tests, the practice of anatomical double bundle anterior cruciate ligament reconstruction with a patellar graft to conventional single bundle reconstruction with the same amount of patellar graft in a paired experimental cadaver study. METHODS: Nine pairs of male cadaver knees ranging in age from 44 to 63 years were randomized into two groups: group A (single bundle and group B (anatomical reconstruction. Each knee was biomechanically tested under three conditions: intact anterior cruciate ligament, reconstructed anterior cruciate ligament, and injured anterior cruciate ligament. Maximum anterior dislocation, rigidity, and passive internal tibia rotation were recorded with knees submitted to a 100 N horizontal anterior dislocation force applied to the tibia with the knees at 30, 60 and 90 degrees of flexion. RESULTS: There were no differences between the two techniques for any of the measurements by ANOVA tests. CONCLUSION: The technique of anatomical double bundle reconstruction of the anterior cruciate ligament with bone-patellar tendon-bone graft has a similar biomechanical behavior with regard to anterior tibial dislocation, rigidity, and passive internal tibial rotation.

  5. Variable recruitment in bundles of miniature pneumatic artificial muscles.

    Science.gov (United States)

    DeLaHunt, Sylvie A; Pillsbury, Thomas E; Wereley, Norman M

    2016-09-13

    The natural compliance and force generation properties of pneumatic artificial muscles (PAMs) allow them to operate like human muscles in anthropomorphic robotic manipulators. Traditionally, manipulators use a single PAM or multiple PAMs actuated in unison in place of a human muscle. However, these standard manipulators can experience significant efficiency losses when operated outside their target performance ranges at low actuation pressures. This study considers the application of a variable recruitment control strategy to a parallel bundle of miniature PAMs as an attempt to mimic the selective recruitment of motor units in a human muscle. Bundles of miniature PAMs are experimentally characterized, their actuation behavior is modeled, and the efficiency gains and losses associated with the application of a variable recruitment control strategy are assessed. This bio-inspired control strategy allows muscle bundles to operate the fewest miniature PAMs necessary to achieve a desired performance objective, improving the muscle bundle's operating efficiency over larger ranges of force generation and displacement. The study also highlights the need for improved PAM fabrication techniques to facilitate the production of identical miniature PAMs for inclusion in muscle bundles.

  6. CANDU fuel bundle deformation modelling with COMSOL multiphysics

    International Nuclear Information System (INIS)

    Bell, J.S.; Lewis, B.J.

    2012-01-01

    Highlights: ► The deformation behaviour of a CANDU fuel bundle was modelled. ► The model has been developed on a commercial finite-element platform. ► Pellet/sheath interaction and end-plate restraint effects were considered. ► The model was benchmarked against the BOW code and a variable-load experiment. - Abstract: A model to describe deformation behaviour of a CANDU 37-element bundle has been developed under the COMSOL Multiphysics finite-element platform. Beam elements were applied to the fuel elements (composed of fuel sheaths and pellets) and endplates in order to calculate the bowing behaviour of the fuel elements. This model is important to help assess bundle-deformation phenomena, which may lead to more restrictive coolant flow through the sub-channels of the horizontally oriented bundle. The bundle model was compared to the BOW code for the occurrence of a dry-out patch, and benchmarked against an out-reactor experiment with a variable load on an outer fuel element.

  7. Fuel bundle to pressure tube fretting in Bruce and Darlington

    Energy Technology Data Exchange (ETDEWEB)

    Norsworthy, A G; Ditschun, A [Atomic Energy of Canada Ltd., Mississauga, ON (Canada)

    1996-12-31

    As the fuel channel elongates due to creep, the fuel string moves relative to the inlet until the fuel pads at the inboard end eventually separate from the spacer sleeve, and the fuel resides on the burnish mark of the pressure tube. The bundle is then supported in a fashion which contributes to increased levels of vibration. Those pads which (due to geometric variation) have contact loads with the pressure tube within a certain range, vibrate, and cause significant fretting on the burnish mark, and further along at the midplane of the bundle. Inspection of the pressure tubes in Bruce A, Bruce B, and Darlington has revealed fret damage up to 0.55 mm at the burnish mark and slightly lower than this at the inlet bundle midplane. To date, all fret marks have been dealt with successfully without the need for tube replacement, but a program of work has been initiated to understand the mechanism and reduce the fretting. Such understanding is necessary to guide future design changes to the fuel bundle, to guide future inspection programs, to guide maintenance programs, and for longer term strategic planning. This paper discusses how the understanding of fretting has evolved and outlines a current hypothesis for the mechanism of fretting. The role of bundle geometry, excitation forces, and reactor conditions are reviewed, along with options under consideration to mitigate damage. (author). 4 refs., 2 tabs., 13 figs.

  8. Revascularization of diaphyseal bone segments by vascular bundle implantation.

    Science.gov (United States)

    Nagi, O N

    2005-11-01

    Vascularized bone transfer is an effective, established treatment for avascular necrosis and atrophic or infected nonunions. However, limited donor sites and technical difficulty limit its application. Vascular bundle transplantation may provide an alternative. However, even if vascular ingrowth is presumed to occur in such situations, its extent in aiding revascularization for ultimate graft incorporation is not well understood. A rabbit tibia model was used to study and compare vascularized, segmental, diaphyseal, nonvascularized conventional, and vascular bundle-implanted grafts with a combination of angiographic, radiographic, histopathologic, and bone scanning techniques. Complete graft incorporation in conventional grafts was observed at 6 months, whereas it was 8 to 12 weeks with either of the vascularized grafts. The pattern of radionuclide uptake and the duration of graft incorporation between vascular segmental bone grafts (with intact endosteal blood supply) and vascular bundle-implanted segmental grafts were similar. A vascular bundle implanted in the recipient bone was found to anastomose extensively with the intraosseous circulation at 6 weeks. Effective revascularization of bone could be seen when a simple vascular bundle was introduced into a segment of bone deprived of its normal blood supply. This simple technique offers promise for improvement of bone graft survival in clinical circumstances.

  9. Fuel bundle to pressure tube fretting in Bruce and Darlington

    International Nuclear Information System (INIS)

    Norsworthy, A.G.; Ditschun, A.

    1995-01-01

    As the fuel channel elongates due to creep, the fuel string moves relative to the inlet until the fuel pads at the inboard end eventually separate from the spacer sleeve, and the fuel resides on the burnish mark of the pressure tube. The bundle is then supported in a fashion which contributes to increased levels of vibration. Those pads which (due to geometric variation) have contact loads with the pressure tube within a certain range, vibrate, and cause significant fretting on the burnish mark, and further along at the midplane of the bundle. Inspection of the pressure tubes in Bruce A, Bruce B, and Darlington has revealed fret damage up to 0.55 mm at the burnish mark and slightly lower than this at the inlet bundle midplane. To date, all fret marks have been dealt with successfully without the need for tube replacement, but a program of work has been initiated to understand the mechanism and reduce the fretting. Such understanding is necessary to guide future design changes to the fuel bundle, to guide future inspection programs, to guide maintenance programs, and for longer term strategic planning. This paper discusses how the understanding of fretting has evolved and outlines a current hypothesis for the mechanism of fretting. The role of bundle geometry, excitation forces, and reactor conditions are reviewed, along with options under consideration to mitigate damage. (author). 4 refs., 2 tabs., 13 figs

  10. Large bundle BWR test CORA-18: Test results

    International Nuclear Information System (INIS)

    Hagen, S.; Hofmann, P.; Noack, V.; Sepold, L.; Schanz, G.; Schumacher, G.

    1998-04-01

    The CORA out-of-pile experiments are part of the international Severe Fuel Damage (SFD) Program. They were performed to provide information on the damage progression of Light Water Reactor (LWR) fuel elements in Loss-of-coolant Accidents in the temperature range 1200 C to 2400 C. CORA-18 was the large BWR bundle test corresponding to the PWR test CORA-7. It should investigate if there exists an influence of the BWR bundle size on the fuel damage behaviour. Therefore, the standard-type BWR CORA bundle with 18 fuel rod simulators was replaced by a large bundle with two additional surrounding rows of 30 rods (48 rods total). Power input and steam flow were increased proportionally to the number of fuel rod simulators to give the same initial heat-up rate of about 1 K/s as in the smaller bundles. Emphasis was put on the initial phase of the damage progression. More information on the chemical composition of initial and intermediate interaction products and their relocation behaviour should be obtained. Therefore, power and steam input were terminated after the onset of the temperature escalation. (orig.) [de

  11. Stress generation by myosin minifilaments in actin bundles

    International Nuclear Information System (INIS)

    Dasanayake, Nilushi L; Carlsson, Anders E

    2013-01-01

    Forces and stresses generated by the action of myosin minifilaments are analyzed in idealized computer-generated actin bundles, and compared to results for isotropic actin networks. The bundles are generated as random collections of actin filaments in two dimensions with constrained orientations, crosslinked and attached to two fixed walls. Myosin minifilaments are placed on actin filament pairs and allowed to move and deform the network so that it exerts forces on the walls. The vast majority of simulation runs end with contractile minifilament stress, because minifilaments rotate into energetically stable contractile configurations. This process is aided by the bending and stretching of actin filaments, which accomodate minifilament rotation. Stresses for bundles are greater than those for isotropic networks, and antiparallel filaments generate more tension than parallel filaments. The forces transmitted by the actin network to the walls of the simulation cell often exceed the tension in the minifilament itself. (paper)

  12. Single-Phase Bundle Flows Including Macroscopic Turbulence Model

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Seung Jun; Yoon, Han Young [KAERI, Daejeon (Korea, Republic of); Yoon, Seok Jong; Cho, Hyoung Kyu [Seoul National University, Seoul (Korea, Republic of)

    2016-05-15

    To deal with various thermal hydraulic phenomena due to rapid change of fluid properties when an accident happens, securing mechanistic approaches as much as possible may reduce the uncertainty arising from improper applications of the experimental models. In this study, the turbulence mixing model, which is well defined in the subchannel analysis code such as VIPRE, COBRA, and MATRA by experiments, is replaced by a macroscopic k-e turbulence model, which represents the aspect of mathematical derivation. The performance of CUPID with macroscopic turbulence model is validated against several bundle experiments: CNEN 4x4 and PNL 7x7 rod bundle tests. In this study, the macroscopic k-e model has been validated for the application to subchannel analysis. It has been implemented in the CUPID code and validated against CNEN 4x4 and PNL 7x7 rod bundle tests. The results showed that the macroscopic k-e turbulence model can estimate the experiments properly.

  13. Betti numbers of graded modules and cohomology of vector bundles

    Science.gov (United States)

    Eisenbud, David; Schreyer, Frank-Olaf

    2009-07-01

    In the remarkable paper Graded Betti numbers of Cohen-Macaulay modules and the multiplicity conjecture, Mats Boij and Jonas Soederberg conjectured that the Betti table of a Cohen-Macaulay module over a polynomial ring is a positive linear combination of Betti tables of modules with pure resolutions. We prove a strengthened form of their conjectures. Applications include a proof of the Multiplicity Conjecture of Huneke and Srinivasan and a proof of the convexity of a fan naturally associated to the Young lattice. With the same tools we show that the cohomology table of any vector bundle on projective space is a positive rational linear combination of the cohomology tables of what we call supernatural vector bundles. Using this result we give new bounds on the slope of a vector bundle in terms of its cohomology.

  14. Symposium on Singularities, Representation of Algebras, and Vector Bundles

    CERN Document Server

    Trautmann, Günther

    1987-01-01

    It is well known that there are close relations between classes of singularities and representation theory via the McKay correspondence and between representation theory and vector bundles on projective spaces via the Bernstein-Gelfand-Gelfand construction. These relations however cannot be considered to be either completely understood or fully exploited. These proceedings document recent developments in the area. The questions and methods of representation theory have applications to singularities and to vector bundles. Representation theory itself, which had primarily developed its methods for Artinian algebras, starts to investigate algebras of higher dimension partly because of these applications. Future research in representation theory may be spurred by the classification of singularities and the highly developed theory of moduli for vector bundles. The volume contains 3 survey articles on the 3 main topics mentioned, stressing their interrelationships, as well as original research papers.

  15. Product bundling as a customer loyalty strategy; Kundenbindung durch Produktbuendel

    Energy Technology Data Exchange (ETDEWEB)

    Wolf, H.G. [Arthur Andersen Business Consulting GmbH, Duesseldorf (Germany)

    2000-12-01

    In the deregulated market in electricity, all marketers and energy-related service providers are competing not only for new customers, but also for customer loyalty. The article sets out concepts and strategies developed by a business consulting firm, for maintaing or enhancing customer loyalty in the end-use market segment, focusing on customized product bundling. A four-tier approach for product bundle development and implementation is discussed. (orig./CB) [German] Fuer Energieversorger und -dienstleister ergibt sich neben der Neukundengewinnung der strategische Zwang zur Bindung bestehender Kunden. An praktischen Ansaetzen fuer Privatkunden stehen neben Value-Added-Services und Incentives (Kundenclub, -karte) nicht zuletzt Produktbuendel (Bundles) zur Verfuegung. Zur erfolgreichen Entwicklung und Implementierung von Produktbuendeln wird ein vierphasiges Vorgehensmodell erlaeutert. (orig./CB)

  16. Implementation of Canflex bundle manufacture - from 'bench scale' to production

    International Nuclear Information System (INIS)

    Pant, A.

    1999-01-01

    Zircatec Precision Industries (ZPI) has been involved with the development of the 43 element Canflex bundle design since 1986. This development included several 'prototype' campaigns involving the manufacture of small quantities of test bundles using enriched fuel. Manufacturing and inspection methods for this fuel were developed at ZPI as the design progressed. The most recent campaign involved the production of 26 bundles of the final Canflex design for a demonstration irradiation in the Point Lepreau Generating Station. This presentation will explore issues pertaining to the introduction of a new product line from initial trial quantities to full production levels. The Canflex fuel experience and a brief review of development efforts will be used as an example. (author)

  17. Designing cooperatively folded abiotic uni- and multimolecular helix bundles

    Science.gov (United States)

    de, Soumen; Chi, Bo; Granier, Thierry; Qi, Ting; Maurizot, Victor; Huc, Ivan

    2018-01-01

    Abiotic foldamers, that is foldamers that have backbones chemically remote from peptidic and nucleotidic skeletons, may give access to shapes and functions different to those of peptides and nucleotides. However, design methodologies towards abiotic tertiary and quaternary structures are yet to be developed. Here we report rationally designed interactional patterns to guide the folding and assembly of abiotic helix bundles. Computational design facilitated the introduction of hydrogen-bonding functionalities at defined locations on the aromatic amide backbones that promote cooperative folding into helix-turn-helix motifs in organic solvents. The hydrogen-bond-directed aggregation of helices not linked by a turn unit produced several thermodynamically and kinetically stable homochiral dimeric and trimeric bundles with structures that are distinct from the designed helix-turn-helix. Relative helix orientation within the bundles may be changed from parallel to tilted on subtle solvent variations. Altogether, these results prefigure the richness and uniqueness of abiotic tertiary structure behaviour.

  18. A study on the thermal hydraulics in rod bundles

    International Nuclear Information System (INIS)

    Chung, Moon Ki; Yang, Sun Kyu

    1989-03-01

    In order to improve the thermal hydraulic characteristics of the nuclear reactor core, it is necessary to obtain better understanding of the coolant flow and the enthalpy distribution in complex rod bundle geometries. The purpose of this report is to obtain a comprehensive survey on the thermal hydraulic in rod bundles from both experimental and numerical point of view. From references on experimental study, measurement methods and results of the flow velocity and the pressure drop in the subchannels of rod bundles are expressed. The microscopic flow characteristics of the subchannels and spacer grid effect on the flow structure are described. Physical phenomena and measurement methods of the secondary flow are also described. From references on the numerical study, general numerical methods are expressed. Numerical studies on the laminar flow and turbulent flow such as 1-equation and 2-equation model are reviewed.(Author)

  19. Heat transfer in tube bundles subjected to blockages. Pt. 1

    International Nuclear Information System (INIS)

    Khattab, M.; Mariy, A.; Habib, M.

    1983-01-01

    The present work is carried out on unblocked test section bundle, half blocked, single ballooning and four ballooning blockages. The hydro-thermal performance of the bundle, (4x4) stainless steel, under each of the previous cases are studied. It is found that the existance of blockages increases the eddies and swirling flow streams. Furthermore, the average heat transfer in a bundle without blockages is superior than that with blockages. The percentage decrease of the average heat transfer coefficient with blockages depends on the position and shape of the blockage. Correlations describing average heat transfer, pressure drop and friction factor are established. All experimental tests are carried out under non-boiling region. (orig.) [de

  20. Engineering biomimetic hair bundle sensors for underwater sensing applications

    Science.gov (United States)

    Kottapalli, Ajay Giri Prakash; Asadnia, Mohsen; Karavitaki, K. Domenica; Warkiani, Majid Ebrahimi; Miao, Jianmin; Corey, David P.; Triantafyllou, Michael

    2018-05-01

    We present the fabrication of an artificial MEMS hair bundle sensor designed to approximate the structural and functional principles of the flow-sensing bundles found in fish neuromast hair cells. The sensor consists of micro-pillars of graded height connected with piezoelectric nanofiber "tip-links" and encapsulated by a hydrogel cupula-like structure. Fluid drag force actuates the hydrogel cupula and deflects the micro-pillar bundle, stretching the nanofibers and generating electric charges. These biomimetic sensors achieve an ultrahigh sensitivity of 0.286 mV/(mm/s) and an extremely low threshold detection limit of 8.24 µm/s. A complete version of this paper has been published [1].

  1. Polarization Raman spectroscopy of GaN nanorod bundles

    International Nuclear Information System (INIS)

    Tite, T.; Lee, C. J.; Chang, Y.-M.

    2010-01-01

    We performed polarization Raman spectroscopy on single wurtzite GaN nanorod bundles grown by plasma-assisted molecular beam epitaxy. The obtained Raman spectra were compared with those of GaN epilayer. The spectral difference between the GaN nanorod bundles and epilayer reveals the relaxation of Raman selection rules in these GaN nanorod bundles. The deviation of polarization-dependent Raman spectroscopy from the prediction of Raman selection rules is attributed to both the orientation of the crystal axis with respect to the polarization vectors of incident and scattered light and the structural defects in the merging boundary of GaN nanorods. The presence of high defect density induced by local strain at the merging boundary was further confirmed by transmission electron microscopy. The averaged defect interspacing was estimated to be around 3 nm based on the spatial correlation model.

  2. Velocity distribution measurement in wire-spaced fuel pin bundle

    International Nuclear Information System (INIS)

    Mizuta, Hiroshi; Ohtake, Toshihide; Uruwashi, Shinichi; Takahashi, Keiichi

    1974-01-01

    Flow distribution measurement was made in the subchannels of a pin bundle in air flow. The present paper is interim because the target of this work is the decision of temperature of the pin surface in contact with wire spacers. The wire-spaced fuel pin bundle used for the experiment consists of 37 simulated fuel pins of stainless steel tubes, 3000 mm in length and 31.6 mm in diameter, which are wound spirally with 6 mm stainless steel wire. The bundle is wrapped with a hexagonal tube, 3500 mm in length and 293 mm in flat-to-flat distance. The bundle is fixed with knock-bar at the entrance of air flow in the hexagonal tube. The pitch of pins in the bundle is 37.6 mm (P/D=1.19) and the wrapping pitch of wire is 1100 mm (H/D=34.8). A pair of arrow-type 5-hole Pitot tubes are used to measure the flow velocity and the direction of air flow in the pin bundle. The measurement of flow distribution was made with the conditions of air flow rate of 0.33 m 3 /sec, air temperature of 45 0 C, and average Reynolds number of 15100 (average air velocity of 20.6 m/sec.). It was found that circular flow existed in the down stream of wire spacers, that axial flow velocity was slower in the subchannels, which contained wire spacers, than in those not affected by the wire, and that the flow angle to the axial velocity at the boundary of subchannels was two thirds smaller than wire wrapping angle. (Tai, I.)

  3. The Analysis of SBWR Critical Power Bundle Using Cobrag Code

    Directory of Open Access Journals (Sweden)

    Yohannes Sardjono

    2013-03-01

    Full Text Available The coolant mechanism of SBWR is similar with the Dodewaard Nuclear Power Plant (NPP in the Netherlands that first went critical in 1968. The similarity of both NPP is cooled by natural convection system. These coolant concept is very related with same parameters on fuel bundle design especially fuel bundle length, core pressure drop and core flow rate as well as critical power bundle. The analysis was carried out by using COBRAG computer code. COBRAG computer code is GE Company proprietary. Basically COBRAG computer code is a tool to solve compressible three-dimensional, two fluid, three field equations for two phase flow. The three fields are the vapor field, the continuous liquid field, and the liquid drop field. This code has been applied to analyses model flow and heat transfer within the reactor core. This volume describes the finitevolume equations and the numerical solution methods used to solve these equations. This analysis of same parameters has been done i.e.; inlet sub cooling 20 BTU/lbm and 40 BTU/lbm, 1000 psi pressure and R-factor is 1.038, mass flux are 0.5 Mlb/hr.ft2, 0.75 Mlb/hr.ft2, 1.00 Mlb/hr.ft2 and 1.25 Mlb/hr.ft2. Those conditions based on history operation of some type of the cell fuel bundle line at GE Nuclear Energy. According to the results, it can be concluded that SBWR critical power bundle is 10.5 % less than current BWR critical power bundle with length reduction of 12 ft to 9 ft.

  4. Cryopreservation of sperm bundles (spermatozeugmata) from endangered livebearing goodeids.

    Science.gov (United States)

    Liu, Yue; Torres, Leticia; Tiersch, Terrence R

    2018-04-14

    More than half of fishes in the family Goodeidae are considered to be endangered, threatened, or vulnerable. Sperm cryopreservation is an effective tool for conserving genetic resources of imperiled populations, but development of protocols with livebearing fishes faces numerous challenges including the natural packaging of sperm into bundles. In this study the cryopreservation of sperm bundles (spermatozeugmata) of three goodeids species was evaluated. Sperm quality was evaluated by activation with NaCl-NaOH solution (at 300 mOsmol/kg and pH 11.8), and analysis of dissociable bundles and dissociation duration. Using Redtail Splitfin (Xenotoca eiseni) as a model, the effects of cryoprotectants (dimethyl sulfoxide, methanol, and glycerol) with different concentrations (5-15% v/v %), equilibration exposure times (1-60 min), cooling rates (5-40 °C/min), concentrations (4 × 10 4 -4 × 10 6 bundles/ml), buffers (HBSS, PBS and NaCl), and buffer osmolalities (200-400 mOsmol/kg) were investigated. After cooling and thawing, sperm bundles maintained their packed form. A specific protocol was developed (10% dimethyl sulfoxide, 20-min equilibration, 10 °C/min cooling rate, 4 × 10 6 bundles/ml, and 300 mOsmol/kg HBSS). This protocol yielded 89 ± 5% of post-thaw dissociable bundles with 209 ± 10 s of dissociation duration for X. eiseni, 96 ± 9% with 814 ± 14 s for Blackfin Goodea (Goodea atripinni), and 66 ± 2% with 726 ± 25 s for Striped Goodeid (Ataeniobius toweri). This is the first study of cryopreservation of sperm within bundles for livebearing fishes and provides a basis for establishment of germplasm repositories for goodeids and other livebearers. Copyright © 2018 Elsevier Inc. All rights reserved.

  5. Status of thermohydraulic studies of wire-wrapped bundles

    International Nuclear Information System (INIS)

    Khairallah, A.; Leteinturier, D.; Skok, J.

    1979-01-01

    A status review is presented of the work undertaken in CEA to acquire good understanding and description of the single-phase thermal-hydraulic problems in LMFBR wire-wrapped bundles. Design-type and reference-type calculational tools developed for the study of forced convection in nominal and distorted bundle geometries are briefly presented. Local hot spots and mixed convection situations are discussed in some more details. Out-of-pile and in-pile experimental programs designed in support to code development are described. (author)

  6. Fuel bundle impact velocities due to reverse flow

    International Nuclear Information System (INIS)

    Wahba, N.N.; Locke, K.E.

    1996-01-01

    If a break should occur in the inlet feeder or inlet header of a CANDU reactor, the rapid depressurization will cause the channel flow(s) to reverse. Depending on the gap between the upstream bundle and shield plug, the string of bundles will accelerate in the reverse direction and impact with the upstream shield plug. The reverse flow impact velocities have been calculated for various operating states for the Bruce NGS A reactors. The sensitivity to several analysis assumptions has been determined. (author)

  7. Laboratory manual for salt mixing test in rod bundles

    International Nuclear Information System (INIS)

    Khan, H.U.R.; Chiu, C.; Todreas, N.

    1978-10-01

    This report is a Laboratory Manual dealing with the procedure employed during Salt Tracer Experiments, which are used for evaluating the hydraulic characteristics of a rod bundle. A description of the standard equipment used is given together with details of manufacture of non-standard items i.e., probes used for detecting the salt-concentration. Details of bundle construction have not been included as they are available in the references cited. An attempt has also been made to point out potential trouble areas and procedures

  8. ASSERT and COBRA predictions of flow distribution in vertical bundles

    International Nuclear Information System (INIS)

    Tahir, A.; Carver, M.B.

    1983-01-01

    COBRA and ASSERT are subchannel codes which compute flow and enthalpy distributions in rod bundles. COBRA is a well known code, ASSERT is under development at CRNL. This paper gives a comparison of the two codes with boiling experiments in vertical seven rod bundles. ASSERT predictions of the void distribution are shown to be in good agreement with reported experimental results, while COBRA predictions are unsatisfactory. The mixing models in both COBRA and ASSERT are briefly discussed. The reasons for the failure of COBRA-IV and the success of ASSERT in simulating the experiments are highlighted

  9. Tube spacer grid for a heat-exchanger tube bundle

    International Nuclear Information System (INIS)

    Scheidl, H.

    1976-01-01

    A tube spacer grid for a heat-exchanger tube bundle is formed by an annular grid frame having a groove formed in its inner surface in which the interspaced grid bars have their ends positioned and held in interspaced relationship by short sections of tubes passed through holes axially formed in the grid frame so that the tubes are positioned between the ends of the grid bars in the grooves. The tube sections may be cut from the same tubes used to form the tube bundle. 5 claims, 3 drawing figures

  10. Cellulosic Fibers: Effect of Processing on Fiber Bundle Strength

    DEFF Research Database (Denmark)

    Thygesen, Anders; Madsen, Bo; Thomsen, Anne Belinda

    2011-01-01

    A range of differently processed cellulosic fibers from flax and hemp plants were investigated to study the relation between processing of cellulosic fibers and fiber bundle strength. The studied processing methods are applied for yarn production and include retting, scutching, carding, and cotto......A range of differently processed cellulosic fibers from flax and hemp plants were investigated to study the relation between processing of cellulosic fibers and fiber bundle strength. The studied processing methods are applied for yarn production and include retting, scutching, carding...

  11. Some Remarks on Group Bundles and C*-dynamical systems

    OpenAIRE

    Vasselli, Ezio

    2003-01-01

    We introduce the notion of fibred action of a group bundle on a C(X)-algebra. By using such a notion, a characterization in terms of induced C*-bundles is given for C*-dynamical systems such that the relative commutant of the fixed-point algebra is minimal (i.e., it is generated by the centre of the given C*-algebra and the centre of the fixed-point algebra). A class of examples in the setting of the Cuntz algebra is given, and connections with superselection structures with nontrivial centre...

  12. Some Remarks on Group Bundles and C* Dynamical Systems

    Science.gov (United States)

    Vasselli, Ezio

    2007-08-01

    We introduce the notion of fibred action of a group bundle on a C(X)-algebra. By using such a notion, a characterization in terms of induced C*-bundles is given for C*-dynamical systems such that the relative commutant of the fixed-point C*-algebra is minimal (i.e., it is generated by the centre of the given C*-algebra and the centre of the fixed-point C*-algebra). A class of examples in the setting of the Cuntz algebra is given, and connections with superselection structures with nontrivial centre are discussed.

  13. Complex Interplay between FleQ, Cyclic Diguanylate and Multiple σ Factors Coordinately Regulates Flagellar Motility and Biofilm Development in Pseudomonas putida.

    Directory of Open Access Journals (Sweden)

    Alicia Jiménez-Fernández

    Full Text Available Most bacteria alternate between a free living planktonic lifestyle and the formation of structured surface-associated communities named biofilms. The transition between these two lifestyles requires a precise and timely regulation of the factors involved in each of the stages that has been likened to a developmental process. Here we characterize the involvement of the transcriptional regulator FleQ and the second messenger cyclic diguanylate in the coordinate regulation of multiple functions related to motility and surface colonization in Pseudomonas putida. Disruption of fleQ caused strong defects in flagellar motility, biofilm formation and surface attachment, and the ability of this mutation to suppress multiple biofilm-related phenotypes associated to cyclic diguanylate overproduction suggests that FleQ mediates cyclic diguanylate signaling critical to biofilm growth. We have constructed a library containing 94 promoters potentially involved in motility and biofilm development fused to gfp and lacZ, screened this library for FleQ and cyclic diguanylate regulation, and assessed the involvement of alternative σ factors σN and FliA in the transcription of FleQ-regulated promoters. Our results suggest a dual mode of action for FleQ. Low cyclic diguanylate levels favor FleQ interaction with σN-dependent promoters to activate the flagellar cascade, encompassing the flagellar cluster and additional genes involved in cyclic diguanylate metabolism, signal transduction and gene regulation. On the other hand, characterization of the FleQ-regulated σN- and FliA-independent PlapA and PbcsD promoters revealed two disparate regulatory mechanisms leading to a similar outcome: the synthesis of biofilm matrix components in response to increased cyclic diguanylate levels.

  14. Proteomic Analysis of Intact Flagella of Procyclic Trypanosoma brucei Cells Identifies Novel Flagellar Proteins with Unique Sub-localization and Dynamics*

    Science.gov (United States)

    Subota, Ines; Julkowska, Daria; Vincensini, Laetitia; Reeg, Nele; Buisson, Johanna; Blisnick, Thierry; Huet, Diego; Perrot, Sylvie; Santi-Rocca, Julien; Duchateau, Magalie; Hourdel, Véronique; Rousselle, Jean-Claude; Cayet, Nadège; Namane, Abdelkader; Chamot-Rooke, Julia; Bastin, Philippe

    2014-01-01

    Cilia and flagella are complex organelles made of hundreds of proteins of highly variable structures and functions. Here we report the purification of intact flagella from the procyclic stage of Trypanosoma brucei using mechanical shearing. Structural preservation was confirmed by transmission electron microscopy that showed that flagella still contained typical elements such as the membrane, the axoneme, the paraflagellar rod, and the intraflagellar transport particles. It also revealed that flagella severed below the basal body, and were not contaminated by other cytoskeletal structures such as the flagellar pocket collar or the adhesion zone filament. Mass spectrometry analysis identified a total of 751 proteins with high confidence, including 88% of known flagellar components. Comparison with the cell debris fraction revealed that more than half of the flagellum markers were enriched in flagella and this enrichment criterion was taken into account to identify 212 proteins not previously reported to be associated to flagella. Nine of these were experimentally validated including a 14-3-3 protein not yet reported to be associated to flagella and eight novel proteins termed FLAM (FLAgellar Member). Remarkably, they localized to five different subdomains of the flagellum. For example, FLAM6 is restricted to the proximal half of the axoneme, no matter its length. In contrast, FLAM8 is progressively accumulating at the distal tip of growing flagella and half of it still needs to be added after cell division. A combination of RNA interference and Fluorescence Recovery After Photobleaching approaches demonstrated very different dynamics from one protein to the other, but also according to the stage of construction and the age of the flagellum. Structural proteins are added to the distal tip of the elongating flagellum and exhibit slow turnover whereas membrane proteins such as the arginine kinase show rapid turnover without a detectible polarity. PMID:24741115

  15. Proteomic analysis of intact flagella of procyclic Trypanosoma brucei cells identifies novel flagellar proteins with unique sub-localization and dynamics.

    Science.gov (United States)

    Subota, Ines; Julkowska, Daria; Vincensini, Laetitia; Reeg, Nele; Buisson, Johanna; Blisnick, Thierry; Huet, Diego; Perrot, Sylvie; Santi-Rocca, Julien; Duchateau, Magalie; Hourdel, Véronique; Rousselle, Jean-Claude; Cayet, Nadège; Namane, Abdelkader; Chamot-Rooke, Julia; Bastin, Philippe

    2014-07-01

    Cilia and flagella are complex organelles made of hundreds of proteins of highly variable structures and functions. Here we report the purification of intact flagella from the procyclic stage of Trypanosoma brucei using mechanical shearing. Structural preservation was confirmed by transmission electron microscopy that showed that flagella still contained typical elements such as the membrane, the axoneme, the paraflagellar rod, and the intraflagellar transport particles. It also revealed that flagella severed below the basal body, and were not contaminated by other cytoskeletal structures such as the flagellar pocket collar or the adhesion zone filament. Mass spectrometry analysis identified a total of 751 proteins with high confidence, including 88% of known flagellar components. Comparison with the cell debris fraction revealed that more than half of the flagellum markers were enriched in flagella and this enrichment criterion was taken into account to identify 212 proteins not previously reported to be associated to flagella. Nine of these were experimentally validated including a 14-3-3 protein not yet reported to be associated to flagella and eight novel proteins termed FLAM (FLAgellar Member). Remarkably, they localized to five different subdomains of the flagellum. For example, FLAM6 is restricted to the proximal half of the axoneme, no matter its length. In contrast, FLAM8 is progressively accumulating at the distal tip of growing flagella and half of it still needs to be added after cell division. A combination of RNA interference and Fluorescence Recovery After Photobleaching approaches demonstrated very different dynamics from one protein to the other, but also according to the stage of construction and the age of the flagellum. Structural proteins are added to the distal tip of the elongating flagellum and exhibit slow turnover whereas membrane proteins such as the arginine kinase show rapid turnover without a detectible polarity. © 2014 by The

  16. The flagellar master operon flhDC is a pleiotropic regulator involved in motility and virulence of the fish pathogen Yersinia ruckeri.

    Science.gov (United States)

    Jozwick, A K S; Graf, J; Welch, T J

    2017-03-01

    To investigate the function of the master flagellar operon flhDC in the fish pathogen Yersinia ruckeri and compare the effect of a constructed flhD mutation to a naturally occurring fliR mutation causing loss-of-motility in emergent biotype 2 (BT2) strains. Yersinia ruckeri flhD and fliR mutants were constructed in a motile strain. Both mutations caused loss-of-motility, ablation of flagellin synthesis and phospholipase secretion, similar to naturally occurring BT2 strains. Transcriptome analysis confirmed flhDC regulation of flagellar, chemotaxis and phospholipase loci as well as other genes of diverse function. The flhD mutation confers a competitive advantage within the fish host when compared with its parent strain, while this advantage was not seen with the naturally occurring fliR mutation. An intact flhD is necessary for expression of the flagellar secretion system as well as other diverse loci, consistent with a role for flhD as a pleiotropic regulator. The maintenance of the flhD locus in Y. ruckeri strains suggests its importance for aspects of Y. ruckeri biology other than virulence, since the flhD mutation conferred a competitive advantage during experimental challenge of rainbow trout. Yersinia ruckeri is the causative agent of enteric red mouth disease, an invasive septicaemia that affects farmed salmonid fish species. Disease outbreaks can cause severe economic losses in aquaculture. BT2 variants, which have independently emerged worldwide, are an increasing threat to farmed fish production. Knowledge of mechanisms involved in virulence, conserved functions and gene regulation among strains may be exploited for the development of novel disease control strategies to prevent pathogen growth or virulence phenotypes within aquaculture. Published 2016. This article is a U.S. Government work and is in the public domain in the USA.

  17. ATG24 Represses Autophagy and Differentiation and Is Essential for Homeostasy of the Flagellar Pocket in Trypanosoma brucei.

    Directory of Open Access Journals (Sweden)

    Ana Brennand

    Full Text Available We have previously identified homologs for nearly half of the approximately 30 known yeast Atg's in the genome database of the human sleeping sickness parasite Trypanosoma brucei. So far, only a few of these homologs have their role in autophagy experimentally confirmed. Among the candidates was the ortholog of Atg24 that is involved in pexophagy in yeast. In T. brucei, the peroxisome-like organelles named glycosomes harbor core metabolic processes, especially glycolysis. In the autotrophic yeast, autophagy is essential for adaptation to different nutritional environments by participating in the renewal of the peroxisome population. We hypothesized that autophagic turnover of the parasite's glycosomes plays a role in differentiation during its life cycle, which demands adaptation to different host environments and associated dramatic changes in nutritional conditions. We therefore characterized T. brucei ATG24, the T. brucei ortholog of yeast Atg24 and mammalian SNX4, and found it to have a regulatory role in autophagy and differentiation as well as endocytic trafficking. ATG24 partially localized on endocytic membranes where it was recruited via PI3-kinase III/VPS34. ATG24 silencing severely impaired receptor-mediated endocytosis of transferrin, but not adsorptive uptake of a lectin, and caused a major enlargement of the flagellar pocket. ATG24 silencing approximately doubled the number of autophagosomes, suggesting a role in repressing autophagy, and strongly accelerated differentiation, in accordance with a role of autophagy in parasite differentiation. Overexpression of the two isoforms of T. brucei ATG8 fused to GFP slowed down differentiation, possibly by a dominant-negative effect. This was overcome by ATG24 depletion, further supporting its regulatory role.

  18. Two new species of Piaroa (Arachnida: Schizomida, Hubbardiidae) from Colombia, with comments on the genus taxonomy and the flagellar setae pattern of Hubbardiinae.

    Science.gov (United States)

    Moreno-González, Jairo A; Delgado-Santa, Leonardo; De Armas, Luis F

    2014-08-14

    Two new species of the genus Piaroa Villarreal, Tourinho & Giupponi, 2008, P. escalerete sp. nov. and P. bacata sp. nov. are described from Valle del Cauca, and Cundinamarca departments, Colombia, respectively. The female flagellum is fully illustrated for a Piaroa species for the first time; the generic diagnosis is also emended and the relationships of the new species with those previously described are discussed. New characters for Piaroa species, a new nomenclature for the chitinized arch and a reinterpretation of the Hubbardiinae flagellar setae pattern are proposed. A distribution map of the known species of Piaroa is provided. 

  19. Negotiating over bundles and prices using aggregate knowledge

    NARCIS (Netherlands)

    Somefun, D.J.A.; Klos, T.B.; Poutré, la J.A.; Bauknecht, K.; Bichler, M.; Pröll, B.

    2004-01-01

    Combining two or more items and selling them as one good, a practice called bundling, can be a very effective strategy for reducing the costs of producing, marketing, and selling goods. In this paper, we consider a form of multi-issue negotiation where a shop negotiates both the contents and the

  20. Vibrations of turbine blades bundles model with rubber damping elements

    Czech Academy of Sciences Publication Activity Database

    Půst, Ladislav; Pešek, Luděk

    2014-01-01

    Roč. 21, č. 1 (2014), s. 45-52 ISSN 1802-1484 R&D Projects: GA ČR GA101/09/1166 Institutional support: RVO:61388998 Keywords : mathematical model * bundle of five blades * rubber damping elements * eigenmodes Subject RIV: BI - Acoustics http://www.engineeringmechanics.cz/obsahy.html?R=21&C=1

  1. Reminiscences Of The First His Bundle Electrography In India

    Directory of Open Access Journals (Sweden)

    Nambiar C.A

    2002-04-01

    Full Text Available Dr Onkar Narula was making a huge wave those days with his work on His Bundle Electrocardiography and Corrected Sinus Node Recovery Time. He visited us in late 1972 or early 1973,probably the latter date. Till then venous catheterizations (including pacing were done by open cut down. I remember the first time we used venous sheath through right femoral vein. Dr Bhatia was the operator and I was assisting him and Dr Savithri Srivasthava was the senior Registrar. With Dr Narula showing the way we did the first His Bundle Recording and I analysed the whole roll manually as was the method those days. We had to improvise a junction box as the recording equipment did not have a proper connecting accessory at that time. After Dr Narula left we did His Bundle recording on many more patients and undertook a study. This was published as: Effect of acute digitalization on His Bundle Intervals and Corrected Sinus Node Recovery Time in young adults.M.L.Bhatia,C.Ashokan Nambiar,S.Shrivastava and Sujoy B.Roy: Indian Heart Journal:Vol-2:1977.1The article was received for publication on 29/11/1973 as acknowledged underneath, but strangely it took a long time to come in print. I have preserved some of the cath rolls and reprint of the article.

  2. Appraising Lexical Bundles in Mathematics Classroom Discourse: Obligation and Choice

    Science.gov (United States)

    Herbel-Eisenmann, Beth; Wagner, David

    2010-01-01

    Working from a large corpus of transcripts from secondary mathematics classrooms, we identify patterns of speech that encode interpersonal positioning. We extend our analysis from a previous article (Herbel-Eisenmann, Wagner & Cortes, Educ Stud Math, 2010, in press), in which we introduced a concept from corpus linguistics--a "lexical bundle,"…

  3. The fiber bundle formalism for the quantization in curved spaces

    International Nuclear Information System (INIS)

    Wyrozumski, T.

    1989-01-01

    We set up a geometrical formulation of the canonical quantization of free Klein-Gordon field on a gravitational background. We introduce the notion of the Bogolubov bundle as the principal fiber bundle over the space of all Cauchy surfaces belonging to some fixed foliation of space-time, with the Bogolubov group as the structure group, as a tool in considering local Bogolubov transformations. Sections of the associated complex structure bundle have the meaning of attaching Hilbert spaces to Cauchy surfaces. We single out, as physical, sections defined by the equation of parallel transport on the Bogolubov bundle. The connection is then subjected to a certain nonlinear differential equation. We find a particular solution, which happens to coincide with a formula given by L.Parker for Robertson-Walker space-times. Finally, we adopt the adiabatic hypothesis as the physical input to the formalism and fix in this way a free parameter in the connection. Concluding, we comment on a possible geometrical interpretation of the regularization of stress-energy tensor and on generalizations of the formalism toward quantum gravity. 14 refs. (Author)

  4. Protecting patients’ electronic health records using enhanced active bundles

    NARCIS (Netherlands)

    Salih, R.M.; Lilien, L.T.; Ben Othmane, L.; Arriaga, R.; Matic, A.

    2012-01-01

    We propose a solution that provides protection for patients' electronic health/medical records disseminated among different authorized healthcare information systems. The solution is known as Active Bundles using a Trusted Third Party (ABTTP). It is based on the use of trusted third parties, and the

  5. Signal Integrity Analysis in Single and Bundled Carbon Nanotube Interconnects

    International Nuclear Information System (INIS)

    Majumder, M.K.; Pandya, N.D.; Kaushik, B.K.; Manhas, S.K.

    2013-01-01

    Carbon nanotube (CN T) can be considered as an emerging interconnect material in current nano scale regime. They are more promising than other interconnect materials such as Al or Cu because of their robustness to electromigration. This research paper aims to address the crosstalk-related issues (signal integrity) in interconnect lines. Different analytical models of single- (SWCNT), double- (DWCNT), and multiwalled CNTs (MWCNT) are studied to analyze the crosstalk delay at global interconnect lengths. A capacitively coupled three-line bus architecture employing CMOS driver is used for accurate estimation of crosstalk delay. Each line in bus architecture is represented with the equivalent RLC models of single and bundled SWCNT, DWCNT, and MWCNT interconnects. Crosstalk delay is observed at middle line (victim) when it switches in opposite direction with respect to the other two lines (aggressors). Using the data predicted by ITRS 2012, a comparative analysis on the basis of crosstalk delay is performed for bundled SWCNT/DWCNT and single MWCNT interconnects. It is observed that the overall crosstalk delay is improved by 40.92% and 21.37% for single MWCNT in comparison to bundled SWCNT and bundled DWCNT interconnects, respectively.

  6. Geometric Description of Fibre Bundle Surface for Birkhoff System

    International Nuclear Information System (INIS)

    Li-Mei, Cao; Hua-Fei, Sun; Zhen-Ning, Zhang

    2009-01-01

    A fibre bundle surface for the Birkhoff system is constructed. The metric and the Riemannian connection of the surface are defined and the representation of the Gaussian curvature of this surface is presented. Finally, three examples for the Birkhoff system are given to illustrate our results. (general)

  7. Self-adjointness of the Gaffney Laplacian on Vector Bundles

    Energy Technology Data Exchange (ETDEWEB)

    Bandara, Lashi, E-mail: lashi.bandara@chalmers.se [Chalmers University of Technology and University of Gothenburg, Mathematical Sciences (Sweden); Milatovic, Ognjen, E-mail: omilatov@unf.edu [University of North Florida, Department of Mathematics and Statistics (United States)

    2015-12-15

    We study the Gaffney Laplacian on a vector bundle equipped with a compatible metric and connection over a Riemannian manifold that is possibly geodesically incomplete. Under the hypothesis that the Cauchy boundary is polar, we demonstrate the self-adjointness of this Laplacian. Furthermore, we show that negligible boundary is a necessary and sufficient condition for the self-adjointness of this operator.

  8. A comprehensive in-pile test of PWR fuel bundle

    Energy Technology Data Exchange (ETDEWEB)

    Kang Rixin; Zhang Shucheng; Chen Dianshan (Academia Sinica, Beijing (China). Inst. of Atomic Energy)

    1991-02-01

    An in-pile test of PWR fuel bundle has been conducted in HWRR at IAE of China. This paper describes the structure of the test bundle (3x3-2), fabrication process and quality control of the fuel rod, irradiation conditions and the main Post Irradiation Examination (PIE) results. The test fuel bundle was irradiated under the PWR operation and water chemistry conditions with an average linear power of 381 W/cm and reached an average burnup of 25010 MWd/tU of the fuel bundle. After the test, destructive and non-destructive examination of the fuel rods was conducted at hot laboratories. The fission gas release was 10.4-23%. The ridge height of cladding was 3 to 8 {mu}m. The hydrogen content of the cladding was 80 to 140 ppm. The fuel stack height was increased by 2.9 to 3.3 mm. The relative irradiation growth was about 0.11 to 0.17% of the fuel rod length. During the irradiation test, no fuel rod failure or other abnormal phenomena had been found by the on-line fuel failure monitoring system of the test loop and water sampling analysis. The structure of the test fuel assembly was left undamaged without twist and detectable deformation. (orig.).

  9. The fibre bundle anatomy of human cruciate ligaments

    NARCIS (Netherlands)

    Mommersteeg, T. J.; Kooloos, J. G.; Blankevoort, L.; Kauer, J. M.; Huiskes, R.; Roeling, F. Q.

    1995-01-01

    The cruciate ligaments of the knee consist of numerous fascicles, groups of which comprise fibre bundles. The stabilising function of these ligaments is established by changes in the lengths and orientations of the fascicles. Understanding the function of knee ligaments thus requires an

  10. Self-adjointness of the Gaffney Laplacian on Vector Bundles

    International Nuclear Information System (INIS)

    Bandara, Lashi; Milatovic, Ognjen

    2015-01-01

    We study the Gaffney Laplacian on a vector bundle equipped with a compatible metric and connection over a Riemannian manifold that is possibly geodesically incomplete. Under the hypothesis that the Cauchy boundary is polar, we demonstrate the self-adjointness of this Laplacian. Furthermore, we show that negligible boundary is a necessary and sufficient condition for the self-adjointness of this operator

  11. Multicell slug flow heat transfer analysis of finite LMFBR bundles

    International Nuclear Information System (INIS)

    Yeung, M.K.; Wolf, L.

    1978-12-01

    An analytical two-dimensional, multi-region, multi-cell technique has been developed for the thermal analysis of LMFBR rod bundles. Local temperature fields of various unit cells were obtained for 7, 19, and 37-rod bundles of different geometries and power distributions. The validity of the technique has been verified by its excellent agreement with the THTB calculational result. By comparing the calculated fully-developed circumferential clad temperature distribution with those of the experimental measurements, an axial correction factor has been derived to account for the entrance effect for practical considerations. Moreover, the knowledge of the local temperature field of the rod bundle leads to the determination of the effective mixing lengths L/sub ij/ for adjacent subchannels of various geometries. It was shown that the implementation of the accurately determined L/sub ij/ into COBRA-IIIC calculations has fairly significant effects on intersubchannel mixing. In addition, a scheme has been proposed to couple the 2-D distributed and lumped parameter calculation by COBRA-IIIC such that the entrance effect can be implanted into the distributed parameter analysis. The technique has demonstrated its applicability for a 7-rod bundle and the results of calculation were compared to those of three-dimensional analyses and experimental measurements

  12. Product Bundling and Shared Information Goods: A Pricing Exercise

    Science.gov (United States)

    Morrison, William G.

    2016-01-01

    In this article, the author describes an exercise in which two pricing problems (product bundling and the sharing of digital information goods) can be understood using the same analytical approach. The exercise allows students to calculate the correct numerical answers with relative ease, while the teaching plan demonstrates the importance of the…

  13. Frobenius Pull Backs of Vector Bundles in Higher Dimensions

    Indian Academy of Sciences (India)

    We prove that for a smooth projective variety of arbitrary dimension and for a vector bundle over , the Harder–Narasimhan filtration of a Frobenius pull back of is a refinement of the Frobenius pull back of the Harder–Narasimhan filtration of , provided there is a lower bound on the characteristic (in terms of rank of ...

  14. Exposure Control Using Adaptive Multi-Stage Item Bundles.

    Science.gov (United States)

    Luecht, Richard M.

    This paper presents a multistage adaptive testing test development paradigm that promises to handle content balancing and other test development needs, psychometric reliability concerns, and item exposure. The bundled multistage adaptive testing (BMAT) framework is a modification of the computer-adaptive sequential testing framework introduced by…

  15. 76 FR 61365 - Bundled Payments for Care Improvement Initiative

    Science.gov (United States)

    2011-10-04

    ...] Bundled Payments for Care Improvement Initiative AGENCY: Centers for Medicare & Medicaid Services (CMS...: Letter of Intent Submission Deadline: For Model 1 of this initiative, interested organizations must...-improvement.html . Application Submission Deadline: For Model 1 of this initiative, applications must be...

  16. Moduli space of Parabolic vector bundles over hyperelliptic curves

    Indian Academy of Sciences (India)

    27

    This has been generalized for higher dimensional varieties by Maruyama ... Key words and phrases. Parabolic structure .... Let E be a vector bundle of rank r on X. Recall that a parabolic ..... Let us understand this picture geometrically. Let ω1 ...

  17. MYOCARDIAL DEFORMATION AND COMPLETE LEFT BUNDLE BRANCH BLOCK

    Directory of Open Access Journals (Sweden)

    E. N. Pavlyukova

    2015-12-01

    Full Text Available Tissue Doppler imaging is evolving as a useful echocardiographic tool for quantitative assessment of left ventricular systolic and diastolic function. Over the last 10 years, myocardial deformation imaging has become possible initially with tissue Doppler , and more recently with myocardial speckle-tracking using 2D echocardiography. Unlike simple tissue velocity measurements, deformation measurements are specific for the region of interest. Strain rate or strain measurements have been used as sensitive indicators for subclinical diseases, and it is the most widely used tool to assess mechanical dyssynchrony. Left bundle branch block is a frequent, etiologically heterogeneous, clinically hostile and diagnostically challenging entity. About 2% of patients underwent cardiac stress testing show stable or intermittent left bundle branch block. Presence of left bundle branch block is associated with a lower and slower diastolic coronary flow velocity especially during hyperemia. Stress echocardiography is the best option for the diagnosis of ischemic heart disease, albeit specificity and sensitivity reduce in patients with left bundle branch block in the territory of left anterior descending artery in presence of initial septum dyskinesia.

  18. A novel microbond bundle pullout technique to evaluate the ...

    Indian Academy of Sciences (India)

    ... pullout technique to evaluate the interfacial properties of fibre-reinforced plastic composites ... https://www.ias.ac.in/article/fulltext/boms/040/04/0737-0744. Keywords. Microbond bundle pullout test; carbon/epoxy; fibre-reinforced composites; ...

  19. Local heat transfer coefficient for turbulent flow in rod bundles

    International Nuclear Information System (INIS)

    Fernandez y Fernandez, E.; Carajilescov, P.

    1983-03-01

    The correlation of the local heat transfer coefficients in heated triangular array of rod bundles, in terms of the flow hydrodynamic parameters is presented. The analysis is made first for fluid with Prandtl numbers varying from moderated to high (Pr>0.2), and then extended to fluids with low Prandtl numbers (0.004 [pt

  20. Early Results of Anatomic Double Bundle Anterior Cruciate Ligament Reconstruction

    Directory of Open Access Journals (Sweden)

    Demet Pepele

    2014-03-01

    Full Text Available Aim: The goal in anterior cruciate ligament reconstruction (ACLR is to restore the normal anatomic structure and function of the knee. In the significant proportion of patients after the traditional single-bundle ACLR, complaints of instability still continue. Anatomic double bundle ACLR may provide normal kinematics in knees, much closer to the natural anatomy. The aim of this study is to clinically assess the early outcomes of our anatomical double bundle ACLR. Material and Method: In our clinic between June 2009 and March 2010, performed the anatomic double bundle ACLR with autogenous hamstring grafts 20 patients were evaluated prospectively with Cincinnati, IKDC and Lysholm scores and in clinically for muscle strength and with Cybex II dynamometer. Results: The mean follow-up is 17.8 months (13-21 months. Patients%u2019 scores of Cincinnati, IKDC and Lysholm were respectively, preoperative 18.1, 39.3 and 39.8, while the post-op increased to 27.2, 76.3 and 86.3. In their last check, 17 percent of the patients according to IKDC scores (85% A (excellent and B (good group and 3 patients took place as C (adequate group. The power measurements of quadriceps and hamstring muscle groups of patients who underwent surgery showed no significant difference compared with the intact knees. Discussion: Double-bundle ACL reconstruction is a satisfactory method. There is a need comparative, long-term studies in large numbers in order to determine improving clinical outcome, preventing degeneration and restoring the knee biomechanics better.

  1. Standardization of Type 2 Diabetes Outpatient Expenditure with Bundled Payment Method in China

    Directory of Open Access Journals (Sweden)

    Guo-Chao Xu

    2016-01-01

    Conclusions: We argued that it is feasible to implement bundled payment on type 2 diabetes outpatient services. Bundled payment is effective to control the increase of outpatient expenditure. Further improvements are needed for the implementation of bundled payment reimbursement standards, together with relevant policies and measures.

  2. Morphology, Growth, and Size Limit of Bacterial Cells

    Science.gov (United States)

    Jiang, Hongyuan; Sun, Sean X.

    2010-07-01

    Bacterial cells utilize a living peptidoglycan network (PG) to separate the cell interior from the surroundings. The shape of the cell is controlled by PG synthesis and cytoskeletal proteins that form bundles and filaments underneath the cell wall. The PG layer also resists turgor pressure and protects the cell from osmotic shock. We argue that mechanical influences alter the chemical equilibrium of the reversible PG assembly and determine the cell shape and cell size. Using a mechanochemical approach, we show that the cell shape can be regarded as a steady state of a growing network under the influence of turgor pressure and mechanical stress. Using simple elastic models, we predict the size of common spherical and rodlike bacteria. The influence of cytoskeletal bundles such as crescentin and MreB are discussed within the context of our model.

  3. Wave equations on a de Sitter fiber bundle. [Semiclassical wave function, bundle space, L-S coupling

    Energy Technology Data Exchange (ETDEWEB)

    Drechsler, W [Max-Planck-Institut fuer Physik und Astrophysik, Muenchen (F.R. Germany)

    1975-01-01

    A gauge theory of strong interaction is developed based on fields defined on a fiber bundle. The structural group of the bundle is taken to be the Lsub(4,1) de Sitter group. An internal variable xi, varying in the fiber over a space-time point x, is introduced as a means to describe - with the help of a semiclassical wave function psi(x,xi) defined on the bundle space - the internal structure of extended hadrons in a framework using differential geometric techniques. Three basic nonlinear wave equations for psi(x,xi) are established which are of integro-differential type. The nonlinear coupling terms in these de Sitter gauge invariant equations represent physically a generalized spin orbit coupling or a generalized spin coupling for the motion taking place in the fiber. The motivation for using a bigger space for the definition of hadronic matter wave functions as well as the implications of this geometric approach to strong interaction physics is discussed in detail, in particular with respect to the problem of hadronic constituents. The proposed fiber bundle formalism allows a dynamical description of extended structures for hadrons without implying the necessity of introducing any constituents.

  4. A Xanthomonas citri subsp citri hypothetical protein related to virulence contains a non-functional HD domain and is implicated in flagellar motility.

    Science.gov (United States)

    Vieira, F C F; Gonçalves, A M; Mendoza, E F R; Ferreira, R M; Costa, M L M; Balbuena, T S; Sebinelli, H G; Ciancaglini, P; Pizauro Junior, J M; Ferro, J A

    2017-08-31

    Citrus canker, caused by the Gram-negative bacterium Xanthomonas citri subsp citri (Xac), severely affects most economically important citrus varieties worldwide. A previous study showed that disruption of the ORF XAC1201 from the Xac 306 strain by transposon Tn5 decreased bacterium virulence in the Rangpur lime host (Citrus limonia L. Osbeck). However, little is known regarding the possible function of the hypothetical protein XAC1201 and how it affects the virulence of Xac 306. Here, we confirmed that disruption of ORF XAC1201 reduces Xac 306 virulence in two different hosts, delaying the onset of typical symptoms. In silico analysis suggested that XAC1201 interacts with the flagellar proteins FliM and FliL, known to be an important factor for virulence. In fact, motility assays revealed that the XAC1201 mutant has a significant difference in motility compared to the wild-type Xac 306. Also, a 3-D structure model revealed modified cofactor binding sites and suggested that XAC1201 has a non-functional HD domain. This hypothesis was confirmed by enzymatic assays performed in purified, XAC1201 recombinant protein expressed in Escherichia coli, which revealed no significant activities previously associated with HD domains for the tested substrates. Thus, the role of the XAC1201 protein in Xac 306 virulence seems to be related to flagellar motility, although a non-classic role for the HD domain cannot be dismissed.

  5. Cloning, purification, crystallization and preliminary X-ray studies of flagellar hook scaffolding protein FlgD from Pseudomonas aeruginosa PAO1

    International Nuclear Information System (INIS)

    Luo, Miao; Niu, Siqiang; Yin, Yibing; Huang, Ailong; Wang, Deqiang

    2009-01-01

    In order to better elucidate the functions of FlgD in flagellar hook biosynthesis, the three-dimensional structure of FlgD is being determined by X-ray crystallography. Here, the expression, purification, crystallization and preliminary crystallographic analysis of FlgD from P. aeruginosa are reported. FlgD regulates the assembly of the hook cap structure to prevent leakage of hook monomers into the medium and hook monomer polymerization and also plays a role in determination of the correct hook length, with the help of the FliK protein. In order to better elucidate the functions of FlgD in flagellar hook biosynthesis, the three-dimensional structure of FlgD is being determined by X-ray crystallography. Here, the expression, purification, crystallization and preliminary crystallographic analysis of FlgD from P. aeruginosa are reported. The crystal belonged to space group I222 and diffracted to a resolution of 2.5 Å, with unit-cell parameters a = 116.47, b = 118.71, c = 118.85 Å. The crystals are most likely to contain three molecules in the asymmetric unit, with a V M value of 2.73 Å 3 Da −1

  6. The C*-algebra of a vector bundle and fields of Cuntz algebras

    OpenAIRE

    Vasselli, Ezio

    2004-01-01

    We study the Pimsner algebra associated with the module of continuous sections of a Hilbert bundle, and prove that it is a continuous bundle of Cuntz algebras. We discuss the role of such Pimsner algebras w.r.t. the notion of inner endomorphism. Furthermore, we study bundles of Cuntz algebras carrying a global circle action, and assign to them a class in the representable KK-group of the zero-grade bundle. We compute such class for the Pimsner algebra of a vector bundle.

  7. Upper-bound fission product release assessment for large break LOCA in CANFLEX bundle reactor core

    International Nuclear Information System (INIS)

    Oh, Duk Ju; Lee, Kang Moon

    1996-07-01

    Quarter-core gap inventory assessment for CANDU-6 reactor core loaded with CANFLEX fuel bundles has been performed as one of the licensing safety analyses required for 24 natural uranium CANFLEX bundle irradiation in CANDU-6 reactor. The quarter-core gap inventory for the CANFLEX bundle core is 5 - 10 times lower than that for the standard bundle core, depending on the half-life of the isotope. The lower gap inventory of the CANFLEX bundle core is attributed to the lower linear power of the CANFLEX bundle compared with the standard bundle. However, the whole core total inventories for both the CANFLEX and standard bundle cores are nearly the same. The 6 - 8 times lower upper-bound fission product releases of the CANFLEX bundle core for large break LOCA than those of the standard bundle core imply that the loading of 24 natural uranium CANFLEX bundles would improve the predicted consequences of the postulated accident described in the Wolsung 2 safety report. 2 tabs., 6 figs., 3 refs. (Author)

  8. Quantitative study of bundle size effect on thermal conductivity of single-walled carbon nanotubes

    Science.gov (United States)

    Feng, Ya; Inoue, Taiki; An, Hua; Xiang, Rong; Chiashi, Shohei; Maruyama, Shigeo

    2018-05-01

    Compared with isolated single-walled carbon nanotubes (SWNTs), thermal conductivity is greatly impeded in SWNT bundles; however, the measurement of the bundle size effect is difficult. In this study, the number of SWNTs in a bundle was determined based on the transferred horizontally aligned SWNTs on a suspended micro-thermometer to quantitatively study the effect of the bundle size on thermal conductivity. Increasing the bundle size significantly degraded the thermal conductivity. For isolated SWNTs, thermal conductivity was approximately 5000 ± 1000 W m-1 K-1 at room temperature, three times larger than that of the four-SWNT bundle. The logarithmical deterioration of thermal conductivity resulting from the increased bundle size can be attributed to the increased scattering rate with neighboring SWNTs based on the kinetic theory.

  9. Modelling anisotropic covariance using stochastic development and sub-Riemannian frame bundle geometry

    DEFF Research Database (Denmark)

    Sommer, Stefan Horst; Svane, Anne Marie

    2017-01-01

    distributions. We discuss a factorization of the frame bundle projection map through this bundle, the natural sub-Riemannian structure of the frame bundle, the effect of holonomy, and the existence of subbundles where the Hormander condition is satisfied such that the Brownian motions have smooth transition......We discuss the geometric foundation behind the use of stochastic processes in the frame bundle of a smooth manifold to build stochastic models with applications in statistical analysis of non-linear data. The transition densities for the projection to the manifold of Brownian motions developed...... in the frame bundle lead to a family of probability distributions on the manifold. We explain how data mean and covariance can be interpreted as points in the frame bundle or, more precisely, in the bundle of symmetric positive definite 2-tensors analogously to the parameters describing Euclidean normal...

  10. An improved partial bundle method for linearly constrained minimax problems

    Directory of Open Access Journals (Sweden)

    Chunming Tang

    2016-02-01

    Full Text Available In this paper, we propose an improved partial bundle method for solving linearly constrained minimax problems. In order to reduce the number of component function evaluations, we utilize a partial cutting-planes model to substitute for the traditional one. At each iteration, only one quadratic programming subproblem needs to be solved to obtain a new trial point. An improved descent test criterion is introduced to simplify the algorithm. The method produces a sequence of feasible trial points, and ensures that the objective function is monotonically decreasing on the sequence of stability centers. Global convergence of the algorithm is established. Moreover, we utilize the subgradient aggregation strategy to control the size of the bundle and therefore overcome the difficulty of computation and storage. Finally, some preliminary numerical results show that the proposed method is effective.

  11. Pressure drop ana velocity measurements in KMRR fuel rod bundles

    International Nuclear Information System (INIS)

    Yagn, Sun Kyu; Chung, Heung June; Chung, Chang Whan; Chun, Se Young; Song, Chul Wha; Won, Soon Yeun; Chung, Moon Ki

    1990-01-01

    The detailed hydraulic characteristic measurements in subchannels of longitudinally finned rod bundles using one-component LDV(Laser Doppler Velocimeter) were performed. Time mean axial velocity, turbulent intensity, and turbulent micro scales, such as time auto-correlation, Eulerian integral and micro scale, Kolmogorov length and time scale, and Taylor micro length scale were measured. The signals from LDV are inherently more or less discontinuous. The spectra of signals having such intermittent defects can be obtained by the fast Fourier transformation (FFT) of the auto-correlation function. The turbulent crossflow mixing rate between neighboring subchannels and dominant frequencies were evaluated from the measured data. Pressure drop data were obtained for the typical 36-element and 18-element fuel rod bundles fabricated by the design requirement of KMRR fuel and for other type of fuels assembled with 6-fin rods to investigate the fin effects on the pressure drop characteristics

  12. CAT reconstruction and potting comparison of a LMFBR fuel bundle

    International Nuclear Information System (INIS)

    Betten, P.R.; Tow, D.M.

    1984-04-01

    A standard Liquid Metal Fast Breeder Reactor (LMFBR) subassembly used in the Experimental Breeder Reactor II (EBR-II) was investigated, by remote techniques, for fuel bundle distortion by both nondestructive and destructive methods, and the results from both methods were compared. The non-destructive method employed neutron tomography to reconstruct the locations of fuel elements through the use of a maximum entropy reconstruction algorithm known as MENT. The destructive method consisted of ''potting'' (a technique that embeds and permanently fixes the fuel elements in a solid matrix) the subassembly, and then cutting and polishing the individual sections. The comparison indicated that the tomography reconstruction provided good results in describing the bundle geometry and spacer-wire locations, with the overall resolution being on the order of a spacer-wire diameter. A dimensional consistency check indicated that the element and spacer-wire dimensions were accurately reproduced in the reconstruction

  13. Balanced metrics for vector bundles and polarised manifolds

    DEFF Research Database (Denmark)

    Garcia Fernandez, Mario; Ross, Julius

    2012-01-01

    leads to a Hermitian-Einstein metric on E and a constant scalar curvature Kähler metric in c_1(L). For special values of α, limits of balanced metrics are solutions of a system of coupled equations relating a Hermitian-Einstein metric on E and a Kähler metric in c1(L). For this, we compute the top two......We consider a notion of balanced metrics for triples (X, L, E) which depend on a parameter α, where X is smooth complex manifold with an ample line bundle L and E is a holomorphic vector bundle over X. For generic choice of α, we prove that the limit of a convergent sequence of balanced metrics...

  14. The design of the DUPIC spent fuel bundle counter

    International Nuclear Information System (INIS)

    Menlove, H.O.; Rinard, P.M.; Kroncke, K.E.; Lee, Y.G.

    1997-05-01

    A neutron coincidence detector had been designed to measure the amount of curium in the fuel bundles and associated process samples used in the direct use of plutonium in Canadian deuterium-uranium (CANDU) fuel cycle. All of the sample categories are highly radioactive from the fission products contained in the pressurized water reactor (PWR) spent fuel feed stock. Substantial shielding is required to protect the He-3 detectors from the intense gamma rays. The Monte Carlo neutron and photon calculational code has been used to design the counter with a uniform response profile along the length of the CANDU-type fuel bundle. Other samples, including cut PWR rods, process powder, waste, and finished rods, can be measured in the system. This report describes the performance characteristics of the counter and support electronics. 3 refs., 23 figs., 6 tabs

  15. Element bow profiles from new and irradiated CANDU fuel bundles

    International Nuclear Information System (INIS)

    Dennier, D.; Manzer, A.M.; Ryz, M.A.

    1996-01-01

    Improved methods of measuring element profiles on new CANDU fuel bundles were developed at the Sheridan Park Engineering Laboratory, and have now been applied in the hot cells at Whiteshell Laboratories. For the first time, the outer element profiles have been compared between new, out-reactor tested, and irradiated fuel elements. The comparison shows that irradiated element deformation is similar to that observed on elements in out-reactor tested bundles. In addition to the restraints applied to the element via appendages, the element profile appears to be strongly influenced by gravity and the end loads applied by local deformation of the endplate. Irradiation creep in the direction of gravity also tends to be a dominant factor. (author)

  16. Catastrophic Failure and Critical Scaling Laws of Fiber Bundle Material

    Directory of Open Access Journals (Sweden)

    Shengwang Hao

    2017-05-01

    Full Text Available This paper presents a spring-fiber bundle model used to describe the failure process induced by energy release in heterogeneous materials. The conditions that induce catastrophic failure are determined by geometric conditions and energy equilibrium. It is revealed that the relative rates of deformation of, and damage to the fiber bundle with respect to the boundary controlling displacement ε0 exhibit universal power law behavior near the catastrophic point, with a critical exponent of −1/2. The proportion of the rate of response with respect to acceleration exhibits a linear relationship with increasing displacement in the vicinity of the catastrophic point. This allows for the prediction of catastrophic failure immediately prior to failure by extrapolating the trajectory of this relationship as it asymptotes to zero. Monte Carlo simulations are completed and these two critical scaling laws are confirmed.

  17. Bundled multi-tube nozzle for a turbomachine

    Science.gov (United States)

    Lacy, Benjamin Paul; Ziminsky, Willy Steve; Johnson, Thomas Edward; Zuo, Baifang; York, William David; Uhm, Jong Ho

    2015-09-22

    A turbomachine includes a compressor, a combustor operatively connected to the compressor, an end cover mounted to the combustor, and an injection nozzle assembly operatively connected to the combustor. The injection nozzle assembly includes a cap member having a first surface that extends to a second surface. The cap member further includes a plurality of openings. A plurality of bundled mini-tube assemblies are detachably mounted in the plurality of openings in the cap member. Each of the plurality of bundled mini-tube assemblies includes a main body section having a first end section and a second end section. A fluid plenum is arranged within the main body section. A plurality of tubes extend between the first and second end sections. Each of the plurality of tubes is fluidly connected to the fluid plenum.

  18. Computing exact bundle compliance control charts via probability generating functions.

    Science.gov (United States)

    Chen, Binchao; Matis, Timothy; Benneyan, James

    2016-06-01

    Compliance to evidenced-base practices, individually and in 'bundles', remains an important focus of healthcare quality improvement for many clinical conditions. The exact probability distribution of composite bundle compliance measures used to develop corresponding control charts and other statistical tests is based on a fairly large convolution whose direct calculation can be computationally prohibitive. Various series expansions and other approximation approaches have been proposed, each with computational and accuracy tradeoffs, especially in the tails. This same probability distribution also arises in other important healthcare applications, such as for risk-adjusted outcomes and bed demand prediction, with the same computational difficulties. As an alternative, we use probability generating functions to rapidly obtain exact results and illustrate the improved accuracy and detection over other methods. Numerical testing across a wide range of applications demonstrates the computational efficiency and accuracy of this approach.

  19. The burnable poisons utilization for fissile enriched CANDU fuel bundle

    Energy Technology Data Exchange (ETDEWEB)

    Serghiuta, D; Nainer, O [Team 3 Solutions, Don Mills, ON (Canada)

    1996-12-31

    Utilization of burnable poison for the fissile enriched fueled CANDU 6 Mk1 core is investigated. The main incentives for this analysis are the reduction of void reactivity effects, the maximization of the fissile content of fresh fuel bundles, and the achievement of better power shape control, in order to preserve the power envelope of the standard 37 rod fuel bundle. The latter allows also the preservation of construction parameters of the standard core (for example: number and location of reactivity devices). It also permits the use of regular shift fueling schemes. The paper makes analyses of MOX weapons-grade plutonium and 1.2% SEU fueled CANDU 6 Mk 1 cores. (author). 6 refs., 4 tabs., 10 figs.

  20. Pressure effects on single wall carbon nanotube bundles

    International Nuclear Information System (INIS)

    Teredesai, P.V.; Sharma, S.M.; Karmakar, S.; Sikka, S.K.; Govindaraj, A.; Rao, C.N.R.

    2001-01-01

    We report high pressure Raman studies on single wall carbon nanotube bundles under hydrostatic conditions using two different pressure transmitting media, alcohol mixture and pure water. The radial and tangential modes show a blue shift when SWNT bundle is immersed in the liquids at ambient pressures. The pressure dependence of the radial modes is the same in both liquids. However, the pressure derivatives dω/dP of the tangential modes are slightly higher for the water medium. Raman results are compared with studies under non-hydrostatic conditions and with recent high-pressure X-ray studies. It is seen that the mode frequencies of the recovered sample after pressure cycling from 26 GPa are downshifted by ∝7-10 cm -1 as compared to the starting sample. (orig.)

  1. Analyses of bundle experiment data using MATRA-h

    Energy Technology Data Exchange (ETDEWEB)

    Lim, In Cheol; Chea, Hee Taek [Korea Atomic Energy Research Institute, Taejon (Korea)

    1998-06-01

    When the construction and operation license for HANARO was renewed in 1995, 25% of CHF penalty was imposed. The reason for this was that the validation work related to the CHF design calculation was not enough for the assurance of CHF margin. As a part of the works to recover this CHF penalty, MATRA-h was developed by implementing the new correlations for the heat transfer, CHF prediction, subcooled void to the MATRA-a, which is the modified version of COBRA-IV-I done by KAERI. Using MATRA-h, the subchannel analyses for the bundle experiment data were performed. The comparison of the code predictions with the experimental results, it was found that the code would give the conservative predictions as far as the CHF in the bundle geometry is concerned. (author). 12 refs., 25 figs., 16 tabs.

  2. Bohr--Sommerfeld Lagrangians of moduli spaces of Higgs bundles

    DEFF Research Database (Denmark)

    Biswas, Indranil; Gammelgaard, Niels Leth; Logares, Marina

    Let $X$ be a compact connected Riemann surface of genus at least two. Let $M_H(r,d)$ denote the moduli space of semistable Higgs bundles on $X$ of rank $r$ and degree $d$. We prove that the compact complex Bohr-Sommerfeld Lagrangians of $M_H(r,d)$ are precisely the irreducible components of the n......Let $X$ be a compact connected Riemann surface of genus at least two. Let $M_H(r,d)$ denote the moduli space of semistable Higgs bundles on $X$ of rank $r$ and degree $d$. We prove that the compact complex Bohr-Sommerfeld Lagrangians of $M_H(r,d)$ are precisely the irreducible components...

  3. Stable chains and vortex equations on complex vector bundles

    International Nuclear Information System (INIS)

    Xi Zhang

    2004-07-01

    In this paper, we study an object on almost Hermitian manifold M consisting of a finite number of J i -holomorphic vector bundles E i over M and homomorphisms φ i :E 1 →E i-1 . We call such an object a J-holomorphic chain. We then prove a Hitchin-Kobayashi correspondence relating the existence of solutions to certain chain vortex equations and an appropriate notion of stability for the corresponding chains. (author)

  4. Detection of muon bundles at large zenith angles

    International Nuclear Information System (INIS)

    Aynutdinov, V.M.; Castellina, A.; Chernov, D.V.; Ezubchenko, A.A.; Fulgione, W.; Kindin, V.V.; Kokoulin, R.P.; Kompaniets, K.G.; Konovalov, A.A.; Mannocchi, G.; Petrukhin, A.A.; Rodin, Yu. N.; Saavedra, O.; Shutenko, V.V.; Trinchero, G.; Vernetto, S.; Vonsovsky, N.N.; Yanson, E.E.; Yashin, I.I.

    1999-01-01

    The large area coordinate detector (DECOR) represents a multilayer system of plastic streamer tube chamber modules surrounding the Cherenkov water calorimeter NEVOD. Experimental data collected during the test expositions of first DECOR supermodules (8 vertical planes with 8.4 m 2 working area) have been analysed, angular and spatial reconstruction accuracies have been estimated. The procedure of the selection of events corresponding to detection of parallel tracks (muon bundles originated in the atmosphere) is discussed

  5. Detection of muon bundles at large zenith angles

    Energy Technology Data Exchange (ETDEWEB)

    Aynutdinov, V.M.; Castellina, A.; Chernov, D.V.; Ezubchenko, A.A.; Fulgione, W.; Kindin, V.V.; Kokoulin, R.P.; Kompaniets, K.G.; Konovalov, A.A.; Mannocchi, G.; Petrukhin, A.A.; Rodin, Yu. N.; Saavedra, O.; Shutenko, V.V.; Trinchero, G.; Vernetto, S.; Vonsovsky, N.N.; Yanson, E.E.; Yashin, I.I

    1999-03-01

    The large area coordinate detector (DECOR) represents a multilayer system of plastic streamer tube chamber modules surrounding the Cherenkov water calorimeter NEVOD. Experimental data collected during the test expositions of first DECOR supermodules (8 vertical planes with 8.4 m{sup 2} working area) have been analysed, angular and spatial reconstruction accuracies have been estimated. The procedure of the selection of events corresponding to detection of parallel tracks (muon bundles originated in the atmosphere) is discussed.

  6. Behavior of a bundle of fast fuel pins under irradiation

    International Nuclear Information System (INIS)

    Marbach, G.; Millet, P.; Robert, J.; Languille, A.

    1979-01-01

    In the French design of fuel elements for fast reactors, great deformation of pins can bring about interaction with the hexagonal tube through the spacer wires. The change in such bundles is described here when the diameter of the cladding increases and the outcome of this reaction (bending and ovalization of pins) is calculated with a simplified model. It is shown that the results achieved agree well with the experimental observations [fr

  7. Downflow film boiling in a rod bundle at low pressure

    International Nuclear Information System (INIS)

    Hochreiter, L.E.; Rosal, E.R.; Fayfich, R.R.

    1978-01-01

    A series of low pressure downflow film boiling heat transfer experiments were conducted in a 14-foot (4.27 m) long electrically heater rod bundle containing 336 heater rods. The resulting data was compared with the Dougall-Rohsenow dispersed flow film boiling correlation. The data was found to lie below this correlation as the quality was increased. It is believed that buoyancy effects decreased the heat transfer in downflow film boiling. (author)

  8. Thermal analysis methods for LMFBR wire wrapped bundles

    International Nuclear Information System (INIS)

    Todreas, N.E.

    1976-11-01

    A note is presented which was written to stimulate an awareness and discussion of the fundamental differences in the formulation of certain existing analysis codes for LMFBR wire wrap bundles. The contention of the note is that for those array types where data exists (one wire per pin, equal start angles), the ENERGY method results for coolant temperature under forced convection conditions provide benchmarks of reliability equal to the results of codes COBRA and TH1-3D

  9. HYDRODISSECTION FOR PRESERVATION OF NEUROVASCULAR BUNDLE DURING RADICAL PROSTATECTOMY

    Directory of Open Access Journals (Sweden)

    H. S. Gevorgyan

    2016-01-01

    Full Text Available Nerve-sparing radical prostatectomy is one of the high-tech operations in urology, and the challenge of the surgeon is not only to remove the prostate tumor, but also to provide a high quality of life. The fact that most questions devoted from patients in a conversation with the surgeon before the operation are devoted to this issue, shows the importance and relevance. At present, the diagnostic methods allow significantly more likely to detect early  prostate cancer, making finding and treatment of these patients more affordable and allows to apply this operation.Lately, it seems urgent to explore the possibility of water jet dissection in the field of urology, in particular, for nerve-sparing prostatectomy. Preservation of erectile function depends largely on the quality of separating the neurovascular bundle. Standard use of electrocautery is associated with damage to the neurovascular bundle.  When performing operations using water-jet mobilization of prostate the selective dissection of tissue is performed. This avoids injury of neurovascular bundle and further postoperative complications. The use of this technique may allow the surgeon to provide a more accurate mobilization prostate and selectively controlled intersection vessels heading to the prostate from the neurovascular bundle, reduce intraoperative blood loss,  maintaining continence, erectile function.This literature review is considered by the experience of using nerve-sparing radical prostatectomy using a water-jet dissector, estimated intraoperative parameters using this method.However, we have the lack of extensive research capabilities of this technique when performing nerve-preserving radical prostatectomy, that does not allow to make a comprehensive presentation on the benefits of this technique and its effects on erectile function and quality of urination, further study of this issue in such a difficult category of patients.

  10. On Rationality of Moduli Spaces of Vector Bundles on Real ...

    Indian Academy of Sciences (India)

    Let be a real form of a Hirzebruch surface. Let M H ( r , c 1 , c 2 ) be the moduli space of vector bundles on . Under some numerical conditions on r , c 1 and c 2 , we identify those M H ( r , c 1 , c 2 ) that are rational. Author Affiliations. Indranil Biswas1 Ronnie Sebastian2. School of Mathematics, Tata Institute of ...

  11. Real parabolic vector bundles over a real curve

    Indian Academy of Sciences (India)

    Abstract. We define real parabolic structures on real vector bundles over a real curve. Let (X,σX ) be a real curve, and let S ⊂ X be a non-empty finite subset of X such that σX (S) = S. Let N ≥ 2 be an integer. We construct an N-fold cyclic cover p : Y → X in the category of real curves, ramified precisely over each point of S, ...

  12. Impact of a VAP bundle in Belgian intensive care units.

    Science.gov (United States)

    Jadot, Laurent; Huyghens, Luc; De Jaeger, Annick; Bourgeois, Marc; Biarent, Dominique; Higuet, Adeline; de Decker, Koen; Vander Laenen, Margot; Oosterlynck, Baudewijn; Ferdinande, Patrick; Reper, Pascal; Brimioulle, Serge; Van Cromphaut, Sophie; De Clety, Stéphane Clement; Sottiaux, Thierry; Damas, Pierre

    2018-05-21

    In order to decrease the incidence of ventilator-associated pneumonia (VAP) in Belgium, a national campaign for implementing a VAP bundle involving assessment of sedation, cuff pressure control, oral care with chlorhexidine and semirecumbent position, was launched in 2011-2012. This report will document the impact of this campaign. On 1 day, once a year from 2010 till 2016, except in 2012, Belgian ICUs were questioned about their ventilated patients. For each of these, data about the application of the bundle and the possible treatment for VAP were recorded. Between 36.6 and 54.8% of the 120 Belgian ICUs participated in the successive surveys. While the characteristics of ventilated patients remained similar throughout the years, the percentage of ventilated patients and especially the duration of ventilation significantly decreased before and after the national VAP bundle campaign. Ventilator care also profoundly changed: Controlling cuff pressure, head positioning above 30° were obtained in more than 90% of cases. Oral care was more frequently performed within a day, using more concentrated solutions of chlorhexidine. Subglottic suctioning also was used but in only 24.7% of the cases in the last years. Regarding the prevalence of VAP, it significantly decreased from 28% of ventilated patients in 2010 to 10.1% in 2016 (p ≤ 0.0001). Although a causal relationship cannot be inferred from these data, the successive surveys revealed a potential impact of the VAP bundle campaign on both the respiratory care of ventilated patients and the prevalence of VAP in Belgian ICUs encouraging them to follow the guidelines.

  13. "Bundle Data" Approach at GES DISC Targeting Natural Hazards

    Science.gov (United States)

    Shie, C. L.; Shen, S.; Kempler, S. J.

    2015-12-01

    Severe natural phenomena such as hurricane, volcano, blizzard, flood and drought have the potential to cause immeasurable property damages, great socioeconomic impact, and tragic loss of human life. From searching to assessing the "Big", i.e., massive and heterogeneous scientific data (particularly, satellite and model products) in order to investigate those natural hazards, it has, however, become a daunting task for Earth scientists and applications researchers, especially during recent decades. The NASA Goddard Earth Sciences Data and Information Service Center (GES DISC) has served "Big" Earth science data, and the pertinent valuable information and services to the aforementioned users of diverse communities for years. In order to help and guide our users to online readily (i.e., with a minimum effort) acquire their requested data from our enormous resource at GES DISC for studying their targeted hazard/event, we have thus initiated a "Bundle Data" approach in 2014, first targeting the hurricane event/topic. We have recently worked on new topics such as volcano and blizzard. The "bundle data" of a specific hazard/event is basically a sophisticated integrated data package consisting of a series of proper datasets containing a group of relevant ("knowledge-based") data variables readily accessible to users via a system-prearranged table linking those data variables to the proper datasets (URLs). This online approach has been developed by utilizing a few existing data services such as Mirador as search engine; Giovanni for visualization; and OPeNDAP for data access, etc. The online "Data Cookbook" site at GES DISC is the current host for the "bundle data". We are now also planning on developing an "Automated Virtual Collection Framework" that shall eventually accommodate the "bundle data", as well as further improve our management in "Big Data".

  14. Post test investigation of the bundle test ESBU-1

    International Nuclear Information System (INIS)

    Hagen, S.; Kapulla, H.; Malauschek, H.; Wallenfels, K.P.; Buescher, B.J.

    1986-08-01

    This KfK report describes the post test investigation of bundle experiment ESBU-1. ESBU-1 was the first of two bundle tests on the temperature escalation of Zircaloy clad fuel rods. The investigation of the temperature escalation is part of the program of out-of-pile experiments performed within the frame work of the PNS - Severe Fuel Damage program. The bundle was composed of a 3x3 fuel rod array of our fuel rod simulators (control tungsten heater, UO 2 -ring pellet and Zircaloy cladding). The length was 0.4 meter. After the test the bundle was embedded in epoxy and cut by a diamant saw. The cross sections are investigated by metallographic, SEM and EMP examinations. The results of these examinations are in good agreement with the seperate effects tests investigation of the PNS SFD-Program and inpile experiments of the Power Burst Facility. The investigations show that liquid Zircaloy dissolves UO 2 by taking away the oxygen from the oxide. Depending on the overall oxygen content the (U,Zr,O)-melt forms at refreezing a) three phases (low oxygen content): metallic α-Zry(U), a uranium-rich metallic (U,Zr)alloy, and a (U,Zr)O 2 mixed oxide, or b) two phases (high oxygen content): α-Zr(O) and the (U,Zr)O 2 mixed oxide. c) In melt regions where the local oxidation was very severe, such as in steam contact, only the (U,Zr)O 2 mixed oxide is formed already at test temperature. Also ZrO 2 formed during the initial time of the test is dissolved by the melt. (orig.) [de

  15. Bundle Data Approach at GES DISC Targeting Natural Hazards

    Science.gov (United States)

    Shie, Chung-Lin; Shen, Suhung; Kempler, Steven J.

    2015-01-01

    Severe natural phenomena such as hurricane, volcano, blizzard, flood and drought have the potential to cause immeasurable property damages, great socioeconomic impact, and tragic loss of human life. From searching to assessing the Big, i.e., massive and heterogeneous scientific data (particularly, satellite and model products) in order to investigate those natural hazards, it has, however, become a daunting task for Earth scientists and applications researchers, especially during recent decades. The NASA Goddard Earth Sciences Data and Information Service Center (GES DISC) has served Big Earth science data, and the pertinent valuable information and services to the aforementioned users of diverse communities for years. In order to help and guide our users to online readily (i.e., with a minimum effort) acquire their requested data from our enormous resource at GES DISC for studying their targeted hazard event, we have thus initiated a Bundle Data approach in 2014, first targeting the hurricane event topic. We have recently worked on new topics such as volcano and blizzard. The bundle data of a specific hazard event is basically a sophisticated integrated data package consisting of a series of proper datasets containing a group of relevant (knowledge--based) data variables readily accessible to users via a system-prearranged table linking those data variables to the proper datasets (URLs). This online approach has been developed by utilizing a few existing data services such as Mirador as search engine; Giovanni for visualization; and OPeNDAP for data access, etc. The online Data Cookbook site at GES DISC is the current host for the bundle data. We are now also planning on developing an Automated Virtual Collection Framework that shall eventually accommodate the bundle data, as well as further improve our management in Big Data.

  16. Weak point property and sections of Picard bundles on a ...

    Indian Academy of Sciences (India)

    Introduction. Debarre had proved that the Jacobian J0(X0) of a smooth curve X0 satisfies the diagonal property (Corollary 2.2 of [6]) i.e., there is a vector bundle of rank equal to the dimension of J0(X0) over J0(X0) × J0(X0), having a section whose zero scheme is the diagonal of J0(X0) × J0(X0). In this note, we generalize ...

  17. Crossed products by endomorphisms, vector bundles and group duality, II

    OpenAIRE

    Vasselli, Ezio

    2004-01-01

    We study C*-algebra endomorphims which are special in a weaker sense w.r.t. the notion introduced by Doplicher and Roberts. We assign to such endomorphisms a geometrical invariant, representing a cohomological obstruction for them to be special in the usual sense. Moreover, we construct the crossed product of a C*-algebra by the action of the dual of a (nonabelian, noncompact) group of vector bundle automorphisms. These crossed products supply a class of examples for such generalized special ...

  18. Feasibility Study for Cobalt Bundle Loading to CANDU Reactor Core

    International Nuclear Information System (INIS)

    Park, Donghwan; Kim, Youngae; Kim, Sungmin

    2016-01-01

    CANDU units are generally used to produce cobalt-60 at Bruce and Point Lepreau in Canada and Embalse in Argentina. China has started production of cobalt-60 using its CANDU 6 Qinshan Phase III nuclear power plant in 2009. For cobalt-60 production, the reactor’s full complement of stainless steel adjusters is replaced with neutronically equivalent cobalt-59 adjusters, which are essentially invisible to reactor operation. With its very high neutron flux and optimized fuel burn-up, the CANDU has a very high cobalt-60 production rate in a relatively short time. This makes CANDU an excellent vehicle for bulk cobalt-60 production. Several studies have been performed to produce cobalt-60 using adjuster rod at Wolsong nuclear power plant. This study proposed new concept for producing cobalt-60 and performed the feasibility study. Bundle typed cobalt loading concept is proposed and evaluated the feasibility to fuel management without physics and system design change. The requirement to load cobalt bundle to the core was considered and several channels are nominated. The production of cobalt-60 source is very depend on the flux level and burnup directly. But the neutron absorption characteristic of cobalt bundle is too high, so optimizing design study is needed in the future

  19. Fabrication of CANFLEX bundle kit for irradiation test in NRU

    International Nuclear Information System (INIS)

    Cho, Moon Sung; Kwon, Hyuk Il; Ji, Chul Goo; Chang, Ho Il; Sim, Ki Seob; Suk, Ho Chun.

    1997-10-01

    CANFLEX bundle kit was prepared at KAERI for the fabrication of complete bundle at AECL. Completed bundle will be used for irradiation test in NRU. Provisions in the 'Quality Assurance Manual for HWR Fuel Projects,' 'Manufacturing Plan' and 'Quality Verification, Inspection and Test Plan' were implemented as appropriately for the preparation of CANFLEX kit. A set of CANFLEX kit consist of 43 fuel sheath of two different sizes with spacers, bearing pads and buttons attached, 2 pieces of end plates and 86 pieces of end caps with two different sizes. All the documents utilized as references for the fabrication such as drawings, specifications, operating instructions, QC instructions and supplier's certificates are specified in this report. Especially, suppliers' certificates and inspection reports for the purchased material as well as KAERI's inspection report are integrated as attachments to this report. Attached to this report are supplier's certificates and KAERI inspection reports for the procured materials and KAERI QC inspection reports for tubes, pads, spacers, buttons, end caps, end plates and fuel sheath. (author). 37 refs

  20. Cotangent bundles over all the Hermitian symmetric spaces

    International Nuclear Information System (INIS)

    Arai, Masato; Baba, Kurando

    2016-01-01

    We construct the N = 2 supersymmetric nonlinear sigma models on the cotangent bundles over all the compact and non-compact Hermitian symmetric spaces. In order to construct them we use the projective superspace formalism which is an N = 2 off-shell superfield formulation in four-dimensional space-time. This formalism allows us to obtain the explicit expression of N = 2 supersymmetric nonlinear sigma models on the cotangent bundles over any Hermitian symmetric spaces in terms of the N =1 superfields, once the Kähler potentials of the base manifolds are obtained. Starting with N = 1 supersymmetric Kähler nonlinear sigma models on the Hermitian symmetric spaces, we extend them into the N = 2 supersymmetric models by using the projective superspace formalism and derive the general formula for the cotangent bundles over all the compact and non-compact Hermitian symmetric spaces. We apply to the formula for the non-compact Hermitian symmetric space E 7 /E 6 × U(1) 1 . (paper)

  1. Mass Transport Through Carbon Nanotube-Polystyrene Bundles

    Science.gov (United States)

    Lin, Rongzhou; Tran, Tuan

    2016-05-01

    Carbon nanotubes have been widely used as test channels to study nanofluidic transport, which has been found to have distinctive properties compared to transport of fluids in macroscopic channels. A long-standing challenge in the study of mass transport through carbon nanotubes (CNTs) is the determination of flow enhancement. Various experimental investigations have been conducted to measure the flow rate through CNTs, mainly based on either vertically aligned CNT membranes or individual CNTs. Here, we proposed an alternative approach that can be used to quantify the mass transport through CNTs. This is a simple method relying on the use of carbon nanotube-polystyrene bundles, which are made of CNTs pulled out from a vertically aligned CNT array and glued together by polystyrene. We experimentally showed by using fluorescent tagging that the composite bundles allowed measureable and selective mass transport through CNTs. This type of composite bundle may be useful in various CNT research areas as they are simple to fabricate, less likely to form macroscopic cracks, and offer a high density of CNT pores while maintaining the aligned morphology of CNTs.

  2. Evaluating pulp stiffness from fibre bundles by ultrasound

    Science.gov (United States)

    Karppinen, Timo; Montonen, Risto; Määttänen, Marjo; Ekman, Axel; Myllys, Markko; Timonen, Jussi; Hæggström, Edward

    2012-06-01

    A non-destructive ultrasonic tester was developed to measure the stiffness of pulp bundles. The mechanical properties of pulp are important when estimating the behaviour of paper under stress. Currently available pulp tests are tedious and alter the fibres structurally and mechanically. The developed tester employs (933 ± 15) kHz tweezer-like ultrasonic transducers and time-of-flight measurement through (9.0 ± 2.5) mm long and (0.8 ± 0.1) mm thick fibre bundles kept at (19.1 ± 0.4) °C and (62 ± 1)% RH. We determined the stiffness of soft wood pulps produced by three kraft pulping modifications: standard kraft pulp, (5.2 ± 0.4) GPa, prehydrolysis kraft pulp, (4.3 ± 0.4) GPa, and alkali extracted prehydrolysis kraft pulp, (3.3 ± 0.4) GPa. Prehydrolysis and alkali extraction processes mainly lowered the hemicellulose content of the pulps, which essentially decreased the fibre-wall stiffness hence impairing the stiffness of the fibre networks. Our results indicate that the method allows ranking of pulps according to their stiffness determined from bundle-like samples taken at an early phase of the papermaking process.

  3. Local thermal-hydraulic behaviour in tight 7-rod bundles

    International Nuclear Information System (INIS)

    Cheng, X.; Yu, Y.Q.

    2009-01-01

    Advanced water-cooled reactor concepts with tight lattices have been proposed worldwide to improve the fuel utilization and the economic competitiveness. In the present work, experimental investigations were performed on thermal-hydraulic behaviour in tight hexagonal 7-rod bundles under both single-phase and two-phase conditions. Freon-12 was used as working fluid due to its convenient operating parameters. Tests were carried out under both single-phase and two-phase flow conditions. Rod surface temperatures are measured at a fixed axial elevation and in various circumferential positions. Test data with different radial power distributions are analyzed. Measured surface temperatures of unheated rods are used for the assessment of and comparison with numerical codes. In addition, numerical simulation using sub-channel analysis code MATRA and the computational fluid dynamics (CFD) code ANSYS-10 is carried out to understand the experimental data and to assess the validity of these codes in the prediction of flow and heat transfer behaviour in tight rod bundle geometries. Numerical results are compared with experimental data. A good agreement between the measured temperatures on the unheated rod surface and the CFD calculation is obtained. Both sub-channel analysis and CFD calculation indicates that the turbulent mixing in the tight rod bundle is significantly stronger than that computed with a well established correlation.

  4. Feasibility Study for Cobalt Bundle Loading to CANDU Reactor Core

    Energy Technology Data Exchange (ETDEWEB)

    Park, Donghwan; Kim, Youngae; Kim, Sungmin [KHNP Central Research Institute, Daejeon (Korea, Republic of)

    2016-10-15

    CANDU units are generally used to produce cobalt-60 at Bruce and Point Lepreau in Canada and Embalse in Argentina. China has started production of cobalt-60 using its CANDU 6 Qinshan Phase III nuclear power plant in 2009. For cobalt-60 production, the reactor’s full complement of stainless steel adjusters is replaced with neutronically equivalent cobalt-59 adjusters, which are essentially invisible to reactor operation. With its very high neutron flux and optimized fuel burn-up, the CANDU has a very high cobalt-60 production rate in a relatively short time. This makes CANDU an excellent vehicle for bulk cobalt-60 production. Several studies have been performed to produce cobalt-60 using adjuster rod at Wolsong nuclear power plant. This study proposed new concept for producing cobalt-60 and performed the feasibility study. Bundle typed cobalt loading concept is proposed and evaluated the feasibility to fuel management without physics and system design change. The requirement to load cobalt bundle to the core was considered and several channels are nominated. The production of cobalt-60 source is very depend on the flux level and burnup directly. But the neutron absorption characteristic of cobalt bundle is too high, so optimizing design study is needed in the future.

  5. Evaluation of the linear power of HANARO test fuel bundles

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Choong Sung; Seo, C. G.; Lee, B. C.; Kim, H. R

    2001-02-01

    The HANARO fuel was developed by AECL and it is configured in a bundle of rods containing uranium silicide. AECL has conducted a variety of tests using specimen in order to achieve its qualification and licensing and the highest linear power was evaluated to be 112.8kW/m. In design stage of HANARO, the best estimated maximum linear power at hot spot was found to occur in the transition core from the initial to the equilibrium and its value was 108kW/m, which exceeds 112.8kW/m if the physics uncertainty of the HANARO nuclear design model is taken into account. Consequently, the licensing body issued the conditional permit to operate HANARO and the fuel integrity at the linear power higher than 112.8kW/m was requested to be confirmed through irradiation tests by realizing its repeatability. Hereby, KAERI designed uninstrumented and instrumented test fuel bundles and conducted their burnup tests. In parallel with the tests, the nuclear design model has been revised and updated to enable us to pursue the pin-by-pin power history. This report describes the best estimated power history of the test fuel bundles using the revised model. In conclusion, HANARO fuel keeps its integrity at power condition greater than 120kW/m.

  6. Fluorescence Endoscopy in vivo based on Fiber-bundle Measurements

    Energy Technology Data Exchange (ETDEWEB)

    Zufiria, B.; Gomez-Garcia, P.; Stamatakis, K.; Vaquero, J.J.; Fresno, M.; Desco, M.; Ripoll, J.; Arranz, A.

    2016-07-01

    High-resolution imaging techniques have become important for the determination of the cellular organization that is coupled to organ function. In many cases the organ can be viewed without the need of ionizing radiation techniques in an easier way. This is the case of the gastrointestinal tract, an organ that can be directly accessed with endoscopy avoiding any invasive procedure. Here we describe the design, assembly and testing of a fluorescence high-resolution endoscope intended for the study of the cellular organization of the colon in an experimental mouse model of colon carcinoma. Access to the colon of the mouse took place using a fiber-optic bundle that redirects the light coming from a LED to produce fluorescence and detect it back through the fiber bundle. Results from in vivo and ex-vivo test using our fluorescence fiber bundle endoscope show altered tissue structure and destruction of the intestinal crypts in tumor-bearing areas compared with healthy tissue. (Author)

  7. A Guide to Bundling Small-scale CDM Projects

    International Nuclear Information System (INIS)

    Mariyappan, J.; Bhardwaj, N.; De Coninck, H.; Van der Linden, N.

    2005-07-01

    Small-scale renewable energy and energy efficiency projects that fit the development needs of many developing countries, can potentially be supported via the Clean Development Mechanism (CDM), one of the Kyoto Protocol's flexible mechanisms for tackling climate change. However, there is concern that due to high transaction costs, as well as many existing barriers, very few investments will be made in small-scale projects, which are often the most suitable development option in countries such as India. In view of this, the 'bundling' together of appropriate small-scale projects on a regional basis has been proposed as a way in which funding can be leveraged from international sources and transaction costs reduced. IT Power, IT Power India and the Energy research Centre of the Netherlands (ECN) are carrying out a 2-year project to establish the capacity within India to enable individual small scale projects to be bundled as a single CDM project. Overall objectives are to develop the necessary institutional capabilities to formulate and implement small scale CDM projects in India; to provide a guide on how to bundle small scale projects under the CDM in developing countries; and to raise the awareness of the potential for investment in small scale energy projects which can gain funding through the CDM

  8. Polymorphic transformation of helical flagella of bacteria

    Science.gov (United States)

    Lim, Sookkyung; Howard Berg Collaboration; William Ko Collaboration; Yongsam Kim Collaboration; Wanho Lee Collaboration; Charles Peskin Collaboration

    2016-11-01

    Bacteria such as E. coli swim in an aqueous environment by utilizing the rotation of flagellar motors and alternate two modes of motility, runs and tumbles. Runs are steady forward swimming driven by bundles of flagellar filaments whose motors are turning CCW; tumbles involve a reorientation of the direction of swimming triggered by motor reversals. During tumbling, the helical flagellum undergoes polymorphic transformations, which is a local change in helical pitch, helical radius, and handedness. In this work, we investigate the underlying mechanism of structural conformation and how this polymorphic transition plays a role in bacterial swimming. National Science Foundation.

  9. Compactifications of the Heterotic string with unitary bundles

    Energy Technology Data Exchange (ETDEWEB)

    Weigand, T.

    2006-05-23

    In this thesis we investigate a large new class of four-dimensional supersymmetric string vacua defined as compactifications of the E{sub 8} x E{sub 8} and the SO(32) heterotic string on smooth Calabi-Yau threefolds with unitary gauge bundles and heterotic five-branes. The first part of the thesis discusses the implementation of this idea into the E{sub 8} x E{sub 8} heterotic string. After specifying a large class of group theoretic embeddings featuring unitary bundles, we analyse the effective four-dimensional N=1 supergravity upon compactification. From the gauge invariant Kaehler potential for the moduli fields we derive a modification of the Fayet-Iliopoulos D-terms arising at one-loop in string perturbation theory. From this we conjecture a one-loop deformation of the Hermitian Yang-Mills equation and introduce the idea of {lambda}-stability as the perturbatively correct stability concept generalising the notion of Mumford stability valid at tree-level. We then proceed to a definition of SO(32) heterotic vacua with unitary gauge bundles in the presence of heterotic five-branes and find agreement of the resulting spectrum with the S-dual framework of Type I/Type IIB orientifolds. A similar analysis of the effective four-dimensional supergravity is performed. Further evidence for the proposed one-loop correction to the stability condition is found by identifying the heterotic corrections as the S-dual of the perturbative part of {pi}-stability as the correct stability concept in Type IIB theory. After reviewing the construction of holomorphic stable vector bundles on elliptically fibered Calabi-Yau manifolds via spectral covers, we provide semi-realistic examples for SO(32) heterotic vacua with Pati-Salam and MSSM-like gauge sectors. We finally discuss the construction of realistic vacua with flipped SU(5) GUT and MSSM gauge group within the E{sub 8} x E{sub 8} framework, based on the embedding of line bundles into both E{sub 8} factors. Some of the appealing

  10. Subsheaves in the tangent bundle: Integrability, stability and positivity

    International Nuclear Information System (INIS)

    Peternell, T.

    2001-01-01

    Special subsheaves E of the tangent bundle T X of a complex projective manifold X often carry important geometric information on X. The most important special properties E can have, are: integrability, maximality, positivity. Integrable subsheaves define a foliation on X and then the structure of the leaves of the foliation will be very interesting. The best situation is when the leaves are compact. Unfortunately this does not happen very often and is extremely difficult to verify. Maximality means that E is a maximal destabilising subsheaf with respect to a given polarisation; this leads to stability properties of the tangent bundle. Finally positivity means that E is an ample vector bundle or ample coherent sheaf in the sense of algebraic geometry. In the special case that E = T X , we obtain cum grano salis manifolds with positive curvature. We study stability properties of the tangent bundle of a Fano manifold X. This is deeply related to the existence problem of a Kahler-Einstein metric, but we will purely concentrate on the algebraic aspects of stability. If b2(X)= 1,then Tx is expected to be semi-stable with respect to the anti-canonical polarisation -Kx = detTx (or even stable). We explain several results which yield the conjecture for large classes of Fano manifolds. Some of the methods are of cohomological nature; some use foliations. If bz(X) 2 2, then Tx is not always semi-stable. There should be a geometric reason for this failure, namely the existence of a Fano fibration whose relative tangent sheaf destabilises Tx. In the final section we first study ample subsheaves E in Tx. There is a general conjecture which should interpolate two important, nowadays already classical, theorems of Wahl and Mori. Wahl's theorem says that if E has rank 1, then X is projective space. Mori's theorem gives the same conclusion when E = Tx. Especially Wahl's theorem is applied several times in the previous sections. Now X should be a projective space also in the

  11. HLM fuel pin bundle experiments in the CIRCE pool facility

    Energy Technology Data Exchange (ETDEWEB)

    Martelli, Daniele, E-mail: daniele.martelli@ing.unipi.it [University of Pisa, Department of Civil and Industrial Engineering, Pisa (Italy); Forgione, Nicola [University of Pisa, Department of Civil and Industrial Engineering, Pisa (Italy); Di Piazza, Ivan; Tarantino, Mariano [Italian National Agency for New Technologies, Energy and Sustainable Economic Development, C.R. ENEA Brasimone (Italy)

    2015-10-15

    Highlights: • The experimental results represent the first set of values for LBE pool facility. • Heat transfer is investigated for a 37-pin electrical bundle cooled by LBE. • Experimental data are presented together with a detailed error analysis. • Nu is computed as a function of the Pe and compared with correlations. • Experimental Nu is about 25% lower than Nu derived from correlations. - Abstract: Since Lead-cooled Fast Reactors (LFR) have been conceptualized in the frame of GEN IV International Forum (GIF), great interest has focused on the development and testing of new technologies related to HLM nuclear reactors. In this frame the Integral Circulation Experiment (ICE) test section has been installed into the CIRCE pool facility and suitable experiments have been carried out aiming to fully investigate the heat transfer phenomena in grid spaced fuel pin bundles providing experimental data in support of European fast reactor development. In particular, the fuel pin bundle simulator (FPS) cooled by lead bismuth eutectic (LBE), has been conceived with a thermal power of about 1 MW and a uniform linear power up to 25 kW/m, relevant values for a LFR. It consists of 37 fuel pins (electrically simulated) placed on a hexagonal lattice with a pitch to diameter ratio of 1.8. The FPS was deeply instrumented by several thermocouples. In particular, two sections of the FPS were instrumented in order to evaluate the heat transfer coefficient along the bundle as well as the cladding temperature in different ranks of sub-channels. Nusselt number in the central sub-channel was therefore calculated as a function of the Peclet number and the obtained results were compared to Nusselt numbers obtained from convective heat transfer correlations available in literature on Heavy Liquid Metals (HLM). Results reported in the present work, represent the first set of experimental data concerning fuel pin bundle behaviour in a heavy liquid metal pool, both in forced and

  12. Rod Bundle Heat Transfer: Steady-State Steam Cooling Experiments

    International Nuclear Information System (INIS)

    Spring, J.P.; McLaughlin, D.M.

    2006-01-01

    Through the joint efforts of the Pennsylvania State University and the United States Nuclear Regulatory Commission, an experimental rod bundle heat transfer (RBHT) facility was designed and built. The rod bundle consists of a 7 x 7 square pitch array with spacer grids and geometry similar to that found in a modern pressurized water reactor. From this facility, a series of steady-state steam cooling experiments were performed. The bundle inlet Reynolds number was varied from 1 400 to 30 000 over a pressure range from 1.36 to 4 bars (20 to 60 psia). The bundle inlet steam temperature was controlled to be at saturation for the specified pressure and the fluid exit temperature exceeded 550 deg. C in the highest power tests. One important quantity of interest is the local convective heat transfer coefficient defined in terms of the local bulk mean temperature of the flow, local wall temperature, and heat flux. Steam temperatures were measured at the center of selected subchannels along the length of the bundle by traversing miniaturized thermocouples. Using an analogy between momentum and energy transport, a method was developed for relating the local subchannel centerline temperature measurement to the local bulk mean temperature. Wall temperatures were measured using internal thermocouples strategically placed along the length of each rod and the local wall heat flux was obtained from an inverse conduction program. The local heat transfer coefficient was calculated from the data at each rod thermocouple location. The local heat transfer coefficients calculated for locations where the flow was fully developed were compared against several published correlations. The Weisman and El-Genk correlations were found to agree best with the RBHT steam cooling data, especially over the range of turbulent Reynolds numbers. The effect of spacer grids on the heat transfer enhancement was also determined from instrumentation placed downstream of the spacer grid locations. The local

  13. Igg Subclasses Targeting the Flagella of Salmonella enterica Serovar Typhimurium Can Mediate Phagocytosis and Bacterial Killing

    Science.gov (United States)

    Goh, Yun Shan; Armour, Kathryn L; Clark, Michael R; Grant, Andrew J; Mastroeni, Pietro

    2016-01-01

    Invasive non-typhoidal Salmonella are a common cause of invasive disease in immuno-compromised individuals and in children. Multi-drug resistance poses challenges to disease control, with a critical need for effective vaccines. Flagellin is an attractive vaccine candidate due to surface exposure and high epitope copy number, but its potential as a target for opsonophacytic antibodies is unclear. We examined the effect of targeting flagella with different classes of IgG on the interaction between Salmonella Typhimurium and a human phagocyte-like cell line, THP-1. We tagged the FliC flagellar protein with a foreign CD52 mimotope (TSSPSAD) and bacteria were opsonized with a panel of humanised CD52 antibodies with the same antigen-binding V-region, but different constant regions. We found that IgG binding to flagella increases bacterial phagocytosis and reduces viable intracellular bacterial numbers. Opsonisation with IgG3, followed by IgG1, IgG4, and IgG2, resulted in the highest level of bacterial uptake and in the highest reduction in the intracellular load of viable bacteria. Taken together, our data provide proof-of-principle evidence that targeting flagella with antibodies can increase the antibacterial function of host cells, with IgG3 being the most potent subclass. These data will assist the rational design of urgently needed, optimised vaccines against iNTS disease. PMID:27366588

  14. Getting the Most from Your CD-ROM Dollars: The CD-ROM Bundle [and] The Pros and Cons of CD-ROM Bundling.

    Science.gov (United States)

    Sarjeant, Eric W.; O'Connor, Mary Ann

    1992-01-01

    Discusses and reviews CD-ROM bundles--i.e., hardware, software and CD-ROM kits--including their features, specifications, drawbacks, and prices. Recommends buying through mail order for the best selection and price. The pros and cons of bundling as a marketing strategy are discussed and a list of vendors is provided. (EA)

  15. One stage revision single-bundle anterior cruciate ligament reconstruction with impacted morselized bone graft following a failed double-bundle reconstruction

    Directory of Open Access Journals (Sweden)

    Ho Jong Ra

    2017-01-01

    Full Text Available Although double-bundle anterior cruciate ligament (ACL reconstruction has theoretical benefits such as more accurate reproduction of ACL anatomy, it is technically more demanding surgery. This report describes the case of a one stage revision single-bundle ACL reconstruction after primary double-bundle ACL reconstruction. A professional dancer had an ACL previously reconstructed with a double-bundle technique, but the femoral tunnels were malpositioned resulting in residual laxity and rotational instability. The previous femoral tunnel positions were vertical and widened. The previous vertical tunnels were filled with impacted bone graft and a revision single-bundle ACL reconstruction was performed via the new femoral tunnel with a 2 O'clock position between the previous two tunnels. After 10 months of postoperative rehabilitation, the patient returned to professional dancing with sound bony union and without any residual instability.

  16. New models of droplet deposition and entrainment for prediction of CHF in cylindrical rod bundles

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Haibin, E-mail: hb-zhang@xjtu.edu.cn [School of Chemical Engineering and Technology, Xi’an Jiaotong University, Xi’an 710049 (China); Department of Chemical Engineering, Imperial College, London SW7 2BY (United Kingdom); Hewitt, G.F. [Department of Chemical Engineering, Imperial College, London SW7 2BY (United Kingdom)

    2016-08-15

    Highlights: • New models of droplet deposition and entrainment in rod bundles is developed. • A new phenomenological model to predict the CHF in rod bundles is described. • The present model is well able to predict CHF in rod bundles. - Abstract: In this paper, we present a new set of model of droplet deposition and entrainment in cylindrical rod bundles based on the previously proposed model for annuli (effectively a “one-rod” bundle) (2016a). These models make it possible to evaluate the differences of the rates of droplet deposition and entrainment for the respective rods and for the outer tube by taking into account the geometrical characteristics of the rod bundles. Using these models, a phenomenological model to predict the CHF (critical heat flux) for upward annular flow in vertical rod bundles is described. The performance of the model is tested against the experimental data of Becker et al. (1964) for CHF in 3-rod and 7-rod bundles. These data include tests in which only the rods were heated and data for simultaneous uniform and non-uniform heating of the rods and the outer tube. It was shown that the predicted CHFs by the present model agree well with the experimental data and with the experimental observation that dryout occurred first on the outer rods in 7-rod bundles. It is expected that the methodology used will be generally applicable in the prediction of CHF in rod bundles.

  17. CFD thermal-hydraulic analysis of a CANDU fuel channel with SEU43 type fuel bundle

    International Nuclear Information System (INIS)

    Catana, A.; Prisecaru, Ilie; Dupleac, D.; Danila, Nicolae

    2009-01-01

    This paper presents the numerical investigation of a CANDU fuel channel using CFD (Computational Fluid Dynamics) methodology approach, when SEU43 fuel bundles are used. Comparisons with STD37 fuel bundles are done in order to evaluate the influence of geometrical differences of the fuel bundle types on fluid flow properties. We adopted a strategy to analyze only the significant segments of fuel channel, namely : - the fuel bundle junctions with adjacent segments; - the fuel bundle spacer planes with adjacent segments; - the fuel bundle segments with turbulence enhancement buttons; - and the regular segments of fuel bundles. The computer code used is an academic version of FLUENT code, available from UPB. The complex flow domain of fuel bundles contained in pressure tube and operating conditions determine a high turbulence flow and in some parts of fuel channel also a multi-phase flow. Numerical simulation of the flow in the fuel channel has been achieved by solving the equations for conservation of mass, momentum and energy. For turbulence model the standard k-model is employed although other turbulence models can be used. In this paper we do not consider heat generation and heat transfer capabilities of CFD methods. Boundary conditions for CFD analysis are provided by system and sub-channel analysis. In this paper the discussion is focused on some flow parameters behaviour at the bundle junction, spacer's plane configuration, etc. of a SEU43 fuel bundle in conditions of a typical CANDU 6 fuel channel starting from some experience gained in a previous work. (authors)

  18. Double-bundle depiction of the anterior cruciate ligament at 3 Tesla

    Energy Technology Data Exchange (ETDEWEB)

    Adriaensen, M.E.A.P.M. [Atrium Medical Center Parkstad, Department of Radiology, Heerlen (Netherlands); Hogan, B. [Sports Surgery Clinic, Department of Radiology, Dublin (Ireland); Al-Bulushi, H.I.J. [Armed Forces Hospital, Department of Radiology, Muscat (Oman); Kavanagh, E.C. [Mater Misericordiae Hospital, Department of Radiology, Dublin (Ireland)

    2012-07-15

    Magnetic resonance imaging on 3 Tesla (3T MRI) with arthroscopic correlation has proven to adequately identify the anteromedial bundle (AMB) and posterolateral bundle (PLB) in cadaver knees. The purpose of this study was to describe the depiction of ACL bundle anatomy on 3T MRI in daily practice. In a retrospective cohort study, we included 50 consecutive patients who underwent standard 3T MRI of the knee and had an intact ACL. Two musculoskeletal radiologists independently reviewed all scans for depiction of ACL bundle anatomy using standardized forms. Descriptive statistics were used. Twenty-three right knees (46%) and 27 left knees (54%) were included in the study. Mean age of the patients was 35 years (range 12 to 68 years); 37 patients were male (74%). ACL bundle anatomy was best depicted in the axial plane in 44 knees (88%) and in the coronal plane in six knees (12%). Two bundles were seen in 47 knees (94%). The AMB was completely seen in 45 knees (90%). The PLB was completely seen in 40 knees (80%). Both bundles were completely seen in 37 knees (76%). The double-bundle anatomy of the ACL is visualized in 94% of patients on 3T MRI. Because of potentially associated clinical benefits, we advocate to report separately on the anteromedial bundle and posterolateral bundle in case of anterior cruciate ligament injury of the knee. (orig.)

  19. Understanding nurses' views on a pressure ulcer prevention care bundle: a first step towards successful implementation.

    Science.gov (United States)

    Chaboyer, Wendy; Gillespie, Brigid M

    2014-12-01

    To explore nurses' views of the barriers and facilitators to the use of a newly devised patient-centred pressure ulcer prevention care bundle. Given pressure ulcer prevention strategies are not implemented consistently, the use of a pressure ulcer care bundle may improve implementation given bundles generally assist in standardising care. A quality improvement project was undertaken after a pressure ulcer prevention care bundle was developed and pilot-tested. Short, conversational interviews with nurse explored their views of a patient-centred pressure ulcer care bundle. Interviews were audio-taped and transcribed. Inductive content analysis was used to analyse the transcripts. A total of 20 nurses were interviewed. Five categories with corresponding subcategories emerged from the analysis. They were increasing awareness of pressure ulcer prevention, prompting pressure ulcer prevention activities, promoting active patient participation, barriers to using a pressure ulcer prevention care bundle and enabling integration of the pressure ulcer prevention care bundle into routine practice. Benefits of using a patient-centred pressure ulcer prevention care bundle may include prompting patients and staff to implement prevention strategies and promote active patient participation in care. The success of the care bundle relied on both patients' willingness to participate and nurses' willingness to incorporate it into their routine work. A patient-centred pressure ulcer prevention care bundle may facilitate more consistent implementation of pressure ulcer prevention strategies and active patient participation in care. © 2014 John Wiley & Sons Ltd.

  20. Dispersions of attractive semiflexible fiberlike colloidal particles from bacterial cellulose microfibrils.

    Science.gov (United States)

    Kuijk, Anke; Koppert, Remco; Versluis, Peter; van Dalen, Gerard; Remijn, Caroline; Hazekamp, Johan; Nijsse, Jaap; Velikov, Krassimir P

    2013-11-26

    We prepared dispersions from bacterial cellulose microfibrils (CMF) of a commercial Nata de Coco source. We used an ultra-high-energy mechanical deagglomeration process that is able to disperse the CMFs from the pellicle in which they are organized in an irregular network. Because of the strong attractions between the CMFs, the dispersion remained highly heterogeneous, consisting of fiber bundles, flocs, and voids spanning tens to hundreds of micrometers depending on concentration. The size of these flocs increased with CMF concentration, the size of the bundles stayed constant, and the size of the voids decreased. The observed percolation threshold in MFC dispersions is lower than the theoretical prediction, which is accounted for by the attractive interactions in the system. Because bacterial cellulose is chemically very pure, it can be used to study the interaction of attractive and highly shape-anisotropic, semiflexible fiberlike colloidal particles.

  1. Flagellar membrane fusion and protein exchange in trypanosomes; a new form of cell-cell communication? [version 1; referees: 2 approved

    Directory of Open Access Journals (Sweden)

    Simon Imhof

    2016-04-01

    Full Text Available Diverse structures facilitate direct exchange of proteins between cells, including plasmadesmata in plants and tunnelling nanotubes in bacteria and higher eukaryotes.  Here we describe a new mechanism of protein transfer, flagellar membrane fusion, in the unicellular parasite Trypanosoma brucei. When fluorescently tagged trypanosomes were co-cultured, a small proportion of double-positive cells were observed. The formation of double-positive cells was dependent on the presence of extracellular calcium and was enhanced by placing cells in medium supplemented with fresh bovine serum. Time-lapse microscopy revealed that double-positive cells arose by bidirectional protein exchange in the absence of nuclear transfer.  Furthermore, super-resolution microscopy showed that this process occurred in ≤1 minute, the limit of temporal resolution in these experiments. Both cytoplasmic and membrane proteins could be transferred provided they gained access to the flagellum. Intriguingly, a component of the RNAi machinery (Argonaute was able to move between cells, raising the possibility that small interfering RNAs are transported as cargo. Transmission electron microscopy showed that shared flagella contained two axonemes and two paraflagellar rods bounded by a single membrane. In some cases flagellar fusion was partial and interactions between cells were transient. In other cases fusion occurred along the entire length of the flagellum, was stable for several hours and might be irreversible. Fusion did not appear to be deleterious for cell function: paired cells were motile and could give rise to progeny while fused. The motile flagella of unicellular organisms are related to the sensory cilia of higher eukaryotes, raising the possibility that protein transfer between cells via cilia or flagella occurs more widely in nature.

  2. Reducing the spread of Acinetobacter baumannii and methicillin-resistant Staphylococcus aureus on a burns unit through the intervention of an infection control bundle.

    Science.gov (United States)

    Barbut, Frédéric; Yezli, Saber; Mimoun, Maurice; Pham, Julien; Chaouat, Marc; Otter, Jonathan A

    2013-05-01

    Methicillin-resistant Staphylococcus aureus (MRSA) and Acinetobacter baumannii are major nosocomial pathogens in burns units. We investigated the impact of an infection control bundle on the incidence of nosocomial MRSA and A. baumannii in our burns unit, comparing a pre-intervention period (December 2006-August 2008) with an intervention period (September 2008-December 2009). The bundle comprised regular hydrogen peroxide vapour (HPV) disinfection of the rooms following discharge of patients colonized or infected by multidrug-resistant bacteria, pre-emptive cohort isolation of newly admitted patients before being proven culture negative, cohorting of colonized or infected patients, installation of two air disinfection systems in the corridors of the unit and improvement of material storage. We also investigated the microbiological efficacy of HPV disinfection by sampling the environment before and after HPV treatments. HPV disinfection eliminated pathogens from the environment and significantly reduced total bacterial surface counts, and total fungal air and surface counts, on both a unit and room scale. The incidence of nosocomial MRSA infection or colonization fell by 89.3% from 7.22 to 0.77 cases/1000 patient days (pcontrol bundle resulted in a significant reduction in the incidence of nosocomial MRSA and A. baumannii in our burns unit and prevented further outbreaks of these organisms. Copyright © 2012 Elsevier Ltd and ISBI. All rights reserved.

  3. High-resolution flow structure measurements in a rod bundle

    Energy Technology Data Exchange (ETDEWEB)

    Ylönen, A. T.

    2013-07-01

    Flow behaviour inside a rod bundle has been an active research topic since the early days of the nuclear power industry. Of particular interest in previous studies have been topics such as flow mixing, two-phase flow structure and mapping of two-phase flow transitions. The optimisation of fuel element design can only be achieved by truly understanding the nature of flow. The ultimate goal in this research is to enhance the heat transfer and increase the critical heat flux, which would improve the fuel economy. A better understanding of the flow would also improve nuclear safety as departure from nucleate boiling (DNB) can be predicted more accurately. The motivation for the current project (SUBFLOW) was to increase knowledge of the complex flow phenomena inside a rod bundle. A dedicated sub-channel flow test facility was designed and constructed at the Paul Scherrer Institut (PSI), Villigen, Switzerland. An adiabatic test loop has an up-scaled (1:2.6) vertical fuel rod bundle model with a 4 × 4 geometry. For the very first time, the wire-mesh sensor measurement technique was implemented in a rod bundle as two 64×64 conductivity wire-mesh sensors were installed in the upper part of the test section. The measurement technique enables one to study single- and two-phase flow behaviour with high spatial and temporal resolution. The research topics addressed in this thesis cover a wide range of flow conditions with and without a spacer grid in a rod bundle. The experimental campaign was started by studying natural mixing of a passive scalar to characterise the development of turbulent diffusion in an injection sub-channel and, later on, cross-mixing between adjacent sub-channels. The results were also used in comparison with the in-house CFD code PSI-Boil that is being developed at PSI. The code could estimate the mixing inside the sub-channel and the transition to cross-mixing with a good accuracy. As a natural transition, the SUBFLOW experiments were continued by

  4. High-resolution flow structure measurements in a rod bundle

    International Nuclear Information System (INIS)

    Ylönen, A. T.

    2013-01-01

    Flow behaviour inside a rod bundle has been an active research topic since the early days of the nuclear power industry. Of particular interest in previous studies have been topics such as flow mixing, two-phase flow structure and mapping of two-phase flow transitions. The optimisation of fuel element design can only be achieved by truly understanding the nature of flow. The ultimate goal in this research is to enhance the heat transfer and increase the critical heat flux, which would improve the fuel economy. A better understanding of the flow would also improve nuclear safety as departure from nucleate boiling (DNB) can be predicted more accurately. The motivation for the current project (SUBFLOW) was to increase knowledge of the complex flow phenomena inside a rod bundle. A dedicated sub-channel flow test facility was designed and constructed at the Paul Scherrer Institut (PSI), Villigen, Switzerland. An adiabatic test loop has an up-scaled (1:2.6) vertical fuel rod bundle model with a 4 × 4 geometry. For the very first time, the wire-mesh sensor measurement technique was implemented in a rod bundle as two 64×64 conductivity wire-mesh sensors were installed in the upper part of the test section. The measurement technique enables one to study single- and two-phase flow behaviour with high spatial and temporal resolution. The research topics addressed in this thesis cover a wide range of flow conditions with and without a spacer grid in a rod bundle. The experimental campaign was started by studying natural mixing of a passive scalar to characterise the development of turbulent diffusion in an injection sub-channel and, later on, cross-mixing between adjacent sub-channels. The results were also used in comparison with the in-house CFD code PSI-Boil that is being developed at PSI. The code could estimate the mixing inside the sub-channel and the transition to cross-mixing with a good accuracy. As a natural transition, the SUBFLOW experiments were continued by

  5. Productivity of the supply system based on whole-tree bundling

    Energy Technology Data Exchange (ETDEWEB)

    Laitila, J. (Finnish Forest Research Inst., Joensuu (Finland)), Email: juha.laitila@metla.fi; Jylhae, P. (Finnish Forest Research Inst., Kannus (Finland)), Email: paula.jylha@metla.fi; Kaerhae, K. (Metsaeteho Oy, Helsinki (Finland)), Email: kalle.karha@metsateho.fi

    2009-07-01

    In the present study, time consumption models for bundle harvesting and forwarding were created by applying regression analyses. The time studies related to on-road transportation were created by applying regression analyses. The time studies related to on-road transportation were focused on comparing the terminal times spent on handling of whole-tree bundles and conventional 5-m pulpwood. The number of whole-tree bundles per truck load and the weights of the payloads were also recorded. The forwarding productivity of whole-tree bundles was about double compared to conventional pulpwood and whole-trees. In on-road transportation, the mean loading and unloading time of whole-tree bundles per truck load was 46 % higher compared to that of conventional 5-m pulpwood. The second prototype of the bundle harvester is under construction, and the time studies are to be continued after accomplishing the machine in the autumn 2009. (orig.)

  6. Experimental study on the effect of heat flux tilt on rod bundle dryout limitation

    International Nuclear Information System (INIS)

    Sugawara, S.; Terunuma, K.; Kamoshida, H.

    1995-01-01

    The effect of heat flux tilt on rod bundle dryout limitation was studied experimentally using a full-scale mock-up test facility and simulated 36-rod fuel bundles in which heater pins have azimuthal nonuniform heat flux distribution (i.e., heat flux tilt). Experimental results for typical lateral power distribution in the bundle indicate that the bundle dryout power with azimuthal heat flux tilt is higher than that without azimuthal heat flux tilt in the entire experimental range. Consequently, it is concluded that the dryout experiment using the test bundle with heater pins which has circumferentially uniform heat flux distribution gives conservative results for the usual lateral power distribution in a bundle in which the relative power of outermost-circle fuel rods is higher than those of middle- and inner-circle ones. (author). 15 refs., 2 tabs., 8 figs

  7. Experimental study on the effect of heat flux tilt on rod bundle dryout limitation

    Energy Technology Data Exchange (ETDEWEB)

    Sugawara, S; Terunuma, K; Kamoshida, H [Power Reactor and Nuclear Fuel Development Corp., Oarai, Ibaraki (Japan). Oarai Engineering Center

    1996-12-31

    The effect of heat flux tilt on rod bundle dryout limitation was studied experimentally using a full-scale mock-up test facility and simulated 36-rod fuel bundles in which heater pins have azimuthal nonuniform heat flux distribution (i.e., heat flux tilt). Experimental results for typical lateral power distribution in the bundle indicate that the bundle dryout power with azimuthal heat flux tilt is higher than that without azimuthal heat flux tilt in the entire experimental range. Consequently, it is concluded that the dryout experiment using the test bundle with heater pins which has circumferentially uniform heat flux distribution gives conservative results for the usual lateral power distribution in a bundle in which the relative power of outermost-circle fuel rods is higher than those of middle- and inner-circle ones. (author). 15 refs., 2 tabs., 8 figs.

  8. Anatomic Double-Bundle Anterior Cruciate Ligament Reconstruction With a Free Quadriceps Tendon Autograft.

    Science.gov (United States)

    Caterev, Sergiu; Nistor, Dan Viorel; Todor, Adrian

    2016-10-01

    Anatomic double-bundle anterior cruciate ligament (ACL) reconstruction aims to restore the 2 functional bundles of the ACL in an attempt to better reproduce the native biomechanics of the injured knee and promote long-term knee health. However, this concept is not fully accepted and is not performed on a standard basis. In addition, the superiority of this technique over the conventional single-bundle technique has been questioned, especially the long-term clinical results. One of the down sides of the double-bundle reconstruction is the complexity of the procedure, with increased risks, operative time, and costs compared with the single-bundle procedure. Also, the revision procedure, if necessary, is more challenging. We propose a technique that has some advantages over the traditional double-bundle procedure, using a single femoral tunnel, 2 tibial tunnels, and a free quadriceps tendon autograft.

  9. An eddy viscosity model for flow in a tube bundle

    International Nuclear Information System (INIS)

    Soussan, D.; Grandotto, M.

    1998-01-01

    The work described in this paper is part of the development of GENEPI a 3-dimensional finite element code, designed for the thermalhydraulic analysis of steam generators. It focuses on the implementation of two-phase flow turbulence-induced viscosity in a tube bundle. The GENEPI code, as other industrial codes, uses the eddy viscosity concept introduced by Boussinesq for single phase flow. The concept assumes that the turbulent momentum transfer is similar to the viscous shear stresses. Eddy viscosity formulation is reasonably well known for single phase flows, especially in simple geometries (i.e., in smooth tube, around a single body, or behind a row of bars/tubes), but there exists very little information on it for two-phase flows. An analogy between single and two-phases is used to set up a model for eddy viscosity. The eddy viscosity model examined in this paper is used for a tube bundle geometry and, therefore, is extended to include anisotropy to the classic model. Each of the main flow directions (cross flow inline, cross flow staggered, and parallel flows) gives rise to a specific eddy viscosity formula. The results from a parametric study indicate that the eddy viscosity in the staggered flow is roughly 1.5 times as large as that for the inline cross flow, 60 times as large as that for the parallel flow, and 105 as large as that for the molecular viscosity. Then, the different terms are combined with each other to result in a global eddy viscosity model for a steam generator tube bundle flow. (author)

  10. Hydrodynamic behavior of a bare rod bundle. [LMFBR

    Energy Technology Data Exchange (ETDEWEB)

    Bartzis, J.G.; Todreas, N.E.

    1977-06-01

    The temperature distribution within the rod bundle of a nuclear reactor is of major importance in nuclear reactor design. However temperature information presupposes knowledge of the hydrodynamic behavior of the coolant which is the most difficult part of the problem due to complexity of the turbulence phenomena. In the present work a 2-equation turbulence model--a strong candidate for analyzing actual three dimensional turbulent flows--has been used to predict fully developed flow of infinite bare rod bundle of various aspect ratios (P/D). The model has been modified to take into account anisotropic effects of eddy viscosity. Secondary flow calculations have been also performed although the model seems to be too rough to predict the secondary flow correctly. Heat transfer calculations have been performed to confirm the importance of anisotropic viscosity in temperature predictions. All numerical calculations for flow and heat have been performed by two computer codes based on the TEACH code. Experimental measurements of the distribution of axial velocity, turbulent axial velocity, turbulent kinetic energy and radial Reynolds stresses were performed in the developing and fully developed regions. A 2-channel Laser Doppler Anemometer working on the Reference mode with forward scattering was used to perform the measurements in a simulated interior subchannel of a triangular rod array with P/D = 1.124. Comparisons between the analytical results and the results of this experiment as well as other experimental data in rod bundle array available in literature are presented. The predictions are in good agreement with the results for the high Reynolds numbers.

  11. Early Lessons on Bundled Payment at an Academic Medical Center.

    Science.gov (United States)

    Jubelt, Lindsay E; Goldfeld, Keith S; Blecker, Saul B; Chung, Wei-Yi; Bendo, John A; Bosco, Joseph A; Errico, Thomas J; Frempong-Boadu, Anthony K; Iorio, Richard; Slover, James D; Horwitz, Leora I

    2017-09-01

    Orthopaedic care is shifting to alternative payment models. We examined whether New York University Langone Medical Center achieved savings under the Centers for Medicare and Medicaid Services Bundled Payments for Care Improvement initiative. This study was a difference-in-differences study of Medicare fee-for-service patients hospitalized from April 2011 to June 2012 and October 2013 to December 2014 for lower extremity joint arthroplasty, cardiac valve procedures, or spine surgery (intervention groups), or for congestive heart failure, major bowel procedures, medical peripheral vascular disorders, medical noninfectious orthopaedic care, or stroke (control group). We examined total episode costs and costs by service category. We included 2,940 intervention episodes and 1,474 control episodes. Relative to the trend in the control group, lower extremity joint arthroplasty episodes achieved the greatest savings: adjusted average episode cost during the intervention period decreased by $3,017 (95% confidence interval [CI], -$6,066 to $31). For cardiac procedures, the adjusted average episode cost decreased by $2,999 (95% CI, -$8,103 to $2,105), and for spinal fusion, it increased by $8,291 (95% CI, $2,879 to $13,703). Savings were driven predominantly by shifting postdischarge care from inpatient rehabilitation facilities to home. Spinal fusion index admission costs increased because of changes in surgical technique. Under bundled payment, New York University Langone Medical Center decreased total episode costs in patients undergoing lower extremity joint arthroplasty. For patients undergoing cardiac valve procedures, evidence of savings was not as strong, and for patients undergoing spinal fusion, total episode costs increased. For all three conditions, the proportion of patients referred to inpatient rehabilitation facilities upon discharge decreased. These changes were not associated with an increase in index hospital length of stay or readmission rate

  12. Thermohydraulic tests of 3x3-rod bundle maquette

    International Nuclear Information System (INIS)

    Ladeira, L.C.D.

    1986-10-01

    The results of a 3x3-rod bundle thermohydraulic research program, performed in the Thermohydraulics Laboratory of NUCLEBRAS' Nuclear Technology Development Center, are briefly described. This program included measurements of pressure drops in one and two-phase flows, heat transfer coefficients, mixing between interconnected subchannels in one-phase flow conditions and critical heat fluxes. The measurements covered the following parameter ranges: heat fluxes from zero to the critical values, pressure ranging from 1 to 15 ata, inlet temperature from 25 to 150 sup(0)C and flow rate from 20 to 300l/min. (author)

  13. Heat transfer in rod bundles with severe clad deformations

    International Nuclear Information System (INIS)

    Ihle, P.

    1984-04-01

    The content of the paper is focused on heat transfer conditions during the reflood phase of a LOCA in slightly to severely deformed PWR fuel rod bundle geometries. The status of analytical and, especially, of experimental work is described as far as it is possible within this frame. Emphasis is placed on the presentation of the results of ''Flooding Experiments with Blocked Arrays'' (FEBA), a program performed at the Kernforschungszentrum Karlsruhe in the frame of the Project Nuclear Safety (PNS). (orig./WL) [de

  14. Numerical simulation of flow-induced vibrations in tube bundles

    International Nuclear Information System (INIS)

    Elisabeth Longatte; Zaky Bendjeddou; Mhamed Souli

    2005-01-01

    Full text of publication follows: In many industrial components mechanical structures like rod cluster control assembly, fuel assembly and heat exchanger tube bundles are submitted to complex flows causing possible vibrations and damage. Fluid forces are usually split into two parts: structure motion independent forces and fluid-elastic forces coupled with tube motion and responsible for possible dynamic instability development leading to possible short term failures through high amplitude vibrations. Most classical fluid force identification methods rely on structure response experimental measurements associated with convenient data processes. Owing to recent improvements in Computational Fluid Dynamics (C.F.D.), numerical fluid force identification is now practicable in the presence of industrial configurations. The present paper is devoted to numerical simulation of flow-induced vibrations of tube bundles submitted to single-phase cross flows by using C.F.D. codes. Direct Numerical Simulation (D.N.S.), Arbitrary Lagrange Euler formulation (A.L.E.) and code coupling process are involved to predict fluid forces responsible for tube bundle vibrations in the presence of fluid structure and fluid-elastic coupling effects. In the presence of strong multi-physics coupling, simulation of flow-induced vibrations requires a fluid structure code coupling process. The methodology consists in solving in the same time thermohydraulics and mechanics problems by using an A.L.E. formulation for the fluid computation. The purpose is to take into account coupling between flow and structure motions in order to be able to capture coupling effects. From a numerical point of view, there are three steps in the computation: the fluid problem is solved on the computational domain; fluid forces acting on the moving tube are estimated; finally they are introduced in the structure solver providing the tube displacement that is used to actualize the fluid computational domain. Specific

  15. Rigidity of minimal submanifolds with flat normal bundle

    Indian Academy of Sciences (India)

    Rigidity of minimal submanifolds with flat normal bundle. 461. = a. ∫. M u2(1+q)+ 2 a f 2 − 2. ∫. M u2q+1f 〈∇f, ∇u〉. − (2q + 1). ∫. M u2qf 2|∇u|2, which gives a .... that depends on n, ϵ and q. We now try to transform (2.15) the right hand side only involved u in the power two. For that, we use Young's inequality: ab ≤ βsas.

  16. Numerical simulation of flow behavior in tight lattice rod bundle

    International Nuclear Information System (INIS)

    Yu Yiqi; Yang Yanhua; Gu Hanyang; Cheng Xu; Song Xiaoming; Wang Xiaojun

    2009-01-01

    The Numerical investigation is performed on the air turbulent flow in triangular rod bundle array. Based on the experimental data, the eddy viscosity turbulent model and the Reynold stress turbulent model are evaluated to simulate the flow behavior in the tight lattice. The results show that SSG Reynolds Stress Model has shown superior predictive performance than other Reynolds-stress models, which indicates that the simulation of the anisotropy of the turbulence is significant in the tight lattice. The result with different Reynolds number and geometry shows that the magnitude of the secondary flow is almost independent of the Reynolds number, but it increases with the decrease of the P/D. (authors)

  17. Transient void fraction measurements in rod bundle geometries

    International Nuclear Information System (INIS)

    Chan, A.M.C.

    1998-01-01

    A new gamma densitometer with a Ba-133 source and a Nal(TI) scintillator operated in the count mode has been designed for transient void fraction measurements in the RD-14M heated channels containing a seven-element heater bundle. The device was calibrated dynamically in the laboratory using an air-water flow loop. The void fraction measured was found to compare well with values obtained using the trapped-water method. The device was also found to follow very well the passage of air slugs in pulsating flow with slug passing frequencies of up to about 1.5 hz. (author)

  18. CAPRICORN subchannel code for sodium boiling in LMFBR fuel bundles

    International Nuclear Information System (INIS)

    Padilla, A. Jr.; Smith, D.E.; O'Dell, L.D.

    1983-01-01

    The CAPRICORN computer code analyzes steady-state and transient, single-phase and boiling problems in LMFBR fuel bundles. CAPRICORN uses the same type of subchannel geometry as the COBRA family of codes and solves a similar system of conservation equations for mass, momentum, and energy. However, CAPRICORN uses a different numerical solution method which allows it to handle the full liquid-to-vapor density change for sodium boiling. Results of the initial comparison with data (the W-1 SLSF pipe rupture experiment) are very promising and provide an optimistic basis for proceeding with further development

  19. Noncommutative vector bundles over fuzzy CPN and their covariant derivatives

    International Nuclear Information System (INIS)

    Dolan, Brian P.; Huet, Idrish; Murray, Sean; O'Connor, Denjoe

    2007-01-01

    We generalise the construction of fuzzy CP N in a manner that allows us to access all noncommutative equivariant complex vector bundles over this space. We give a simplified construction of polarization tensors on S 2 that generalizes to complex projective space, identify Laplacians and natural noncommutative covariant derivative operators that map between the modules that describe noncommuative sections. In the process we find a natural generalization of the Schwinger-Jordan construction to su(n) and identify composite oscillators that obey a Heisenberg algebra on an appropriate Fock space

  20. Maximum allowable heat flux for a submerged horizontal tube bundle

    International Nuclear Information System (INIS)

    McEligot, D.M.

    1995-01-01

    For application to industrial heating of large pools by immersed heat exchangers, the socalled maximum allowable (or open-quotes criticalclose quotes) heat flux is studied for unconfined tube bundles aligned horizontally in a pool without forced flow. In general, we are considering boiling after the pool reaches its saturation temperature rather than sub-cooled pool boiling which should occur during early stages of transient operation. A combination of literature review and simple approximate analysis has been used. To date our main conclusion is that estimates of q inch chf are highly uncertain for this configuration