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Sample records for fibril load transmission

  1. Human islet amyloid polypeptide fibril binding to catalase: a transmission electron microscopy and microplate study.

    Science.gov (United States)

    Milton, Nathaniel G N; Harris, J Robin

    2010-05-18

    The diabetes-associated human islet amyloid polypeptide (IAPP) is a 37-amino-acid peptide that forms fibrils in vitro and in vivo. Human IAPP fibrils are toxic in a similar manner to Alzheimer's amyloid-beta (A-beta) and prion protein (PrP) fibrils. Previous studies have shown that catalase binds to A-beta fibrils and appears to recognize a region containing the Gly-Ala-Ile-Ile sequence that is similar to the Gly-Ala-Ile-Leu sequence found in human IAPP residues 24-27. This study presents a transmission electron microscopy (TEM)-based analysis of fibril formation and the binding of human erythrocyte catalase to IAPP fibrils. The results show that human IAPP 1-37, 8-37, and 20-29 peptides form fibrils with diverse and polymorphic structures. All three forms of IAPP bound catalase, and complexes of IAPP 1-37 or 8-37 with catalase were identified by immunoassay. The binding of biotinylated IAPP to catalase was high affinity with a KD of 0.77 nM, and could be inhibited by either human or rat IAPP 1-37 and 8-37 forms. Fibrils formed by the PrP 118-135 peptide with a Gly-Ala-Val-Val sequence also bound catalase. These results suggest that catalase recognizes a Gly-Ala-Ile-Leu-like sequence in amyloid fibril-forming peptides. For IAPP 1-37 and 8-37, the catalase binding was primarily directed towards fibrillar rather than ribbon-like structures, suggesting differences in the accessibility of the human IAPP 24-27 Gly-Ala-Ile-Leu region. This suggests that catalase may be able to discriminate between different structural forms of IAPP fibrils. The ability of catalase to bind IAPP, A-beta, and PrP fibrils demonstrates the presence of similar accessible structural motifs that may be targets for antiamyloid therapeutic development.

  2. Human Islet Amyloid Polypeptide Fibril Binding to Catalase: A Transmission Electron Microscopy and Microplate Study

    Directory of Open Access Journals (Sweden)

    Nathaniel G. N. Milton

    2010-01-01

    Full Text Available The diabetes-associated human islet amyloid polypeptide (IAPP is a 37-amino-acid peptide that forms fibrils in vitro and in vivo. Human IAPP fibrils are toxic in a similar manner to Alzheimer's amyloid-β (Aβ and prion protein (PrP fibrils. Previous studies have shown that catalase binds to Aβ fibrils and appears to recognize a region containing the Gly-Ala-Ile-Ile sequence that is similar to the Gly-Ala-Ile-Leu sequence found in human IAPP residues 24-27. This study presents a transmission electron microscopy (TEM—based analysis of fibril formation and the binding of human erythrocyte catalase to IAPP fibrils. The results show that human IAPP 1-37, 8-37, and 20-29 peptides form fibrils with diverse and polymorphic structures. All three forms of IAPP bound catalase, and complexes of IAPP 1-37 or 8-37 with catalase were identified by immunoassay. The binding of biotinylated IAPP to catalase was high affinity with a KD of 0.77nM, and could be inhibited by either human or rat IAPP 1-37 and 8-37 forms. Fibrils formed by the PrP 118-135 peptide with a Gly-Ala-Val-Val sequence also bound catalase. These results suggest that catalase recognizes a Gly-Ala-Ile-Leu—like sequence in amyloid fibril-forming peptides. For IAPP 1-37 and 8-37, the catalase binding was primarily directed towards fibrillar rather than ribbon-like structures, suggesting differences in the accessibility of the human IAPP 24-27 Gly-Ala-Ile-Leu region. This suggests that catalase may be able to discriminate between different structural forms of IAPP fibrils. The ability of catalase to bind IAPP, Aβ, and PrP fibrils demonstrates the presence of similar accessible structural motifs that may be targets for antiamyloid therapeutic development.

  3. Fibril deformation under load of the rabbit Achilles tendon and medial collateral ligament femoral entheses.

    Science.gov (United States)

    Sevick, Johnathan L; Abusara, Ziad; Andrews, Stephen H; Xu, Minjia; Khurshid, Saad; Chatha, Jansher; Hart, David A; Shrive, Nigel G

    2018-04-10

    Microscopic visualization under load of the region connecting ligaments/tendons to bone, the enthesis, has been performed previously; however, specific investigation of individual fibril deformation may add insight to such studies. Detailed visualization of fibril deformation would inform on the mechanical strategies employed by this tissue in connecting two mechanically disparate materials. Clinically, an improved understanding of enthesis mechanics may help guide future restorative efforts for torn or injured ligaments/tendons, where the enthesis is often a point of weakness. In this study, a custom ligament/tendon enthesis loading device was designed and built, a unique method of sample preparation was devised, and second harmonic and two-photon fluorescence microscopy were used to capture the fibril-level load response of the rabbit Achilles tendon and medial collateral ligament femoral entheses. A focus was given to investigation of the mechanical problem of fibril embedment. Resultant images indicate a rapid (occurring over approximately 60 μm) change in fibril orientation at the interface of ligament/tendon and calcified fibrocartilage early in the loading regime, before becoming relatively constant. Such a change in fibril angle helps confirm the materially graded region demonstrated by others, while, in this case, providing additional insight into fibril bending. We speculate that the scale of the mechanical problem (i.e., fibril diameters being on the order of 250 nm) allows fibrils to bend over the small (relative to the imaging field of view, but large relative to fibril diameter) distances observed; thus, potentially lessening required embedment lengths. Nevertheless, this behavior merits further investigation to be confirmed. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

  4. Evidence that interfibrillar load transfer in tendon is supported by small diameter fibrils and not extrafibrillar tissue components.

    Science.gov (United States)

    Szczesny, Spencer E; Fetchko, Kristen L; Dodge, George R; Elliott, Dawn M

    2017-10-01

    Collagen fibrils in tendon are believed to be discontinuous and transfer tensile loads through shear forces generated during interfibrillar sliding. However, the structures that transmit these interfibrillar forces are unknown. Various extrafibrillar tissue components (e.g., glycosaminoglycans, collagens XII and XIV) have been suggested to transmit interfibrillar loads by bridging collagen fibrils. Alternatively, collagen fibrils may interact directly through physical fusions and interfibrillar branching. The objective of this study was to test whether extrafibrillar proteins are necessary to transmit load between collagen fibrils or if interfibrillar load transfer is accomplished directly by the fibrils themselves. Trypsin digestions were used to remove a broad spectrum of extrafibrillar proteins and measure their contribution to the multiscale mechanics of rat tail tendon fascicles. Additionally, images obtained from serial block-face scanning electron microscopy were used to determine the three-dimensional fibrillar organization in tendon fascicles and identify any potential interfibrillar interactions. While trypsin successfully removed several extrafibrillar tissue components, there was no change in the macroscale fascicle mechanics or fibril:tissue strain ratio. Furthermore, the imaging data suggested that a network of smaller diameter fibrils (wind around and fuse with their neighboring larger diameter fibrils. These findings demonstrate that interfibrillar load transfer is not supported by extrafibrillar tissue components and support the hypothesis that collagen fibrils are capable of transmitting loads themselves. Conclusively determining how fibrils bear load within tendon is critical for identifying the mechanisms that impair tissue function with degeneration and for restoring tissue properties via cell-mediated regeneration or engineered tissue replacements. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35

  5. LOADING OF MECHANICAL TRANSMISSION OF TROLLEYBUS TRACTION DRIVING GEAR

    Directory of Open Access Journals (Sweden)

    A. I. Safonov

    2009-01-01

    Full Text Available The paper analyzes factors that determine dynamic loads of mechanical transmission of trolleybus traction driving gear. The paper proposes a methodology for determination of calculative moments of loading transmission elements. Results of the research are analyzed and recommendations on  dynamic reduction of trolleybus transmission are given in the paper. 

  6. Genesis of mammalian prions: from non-infectious amyloid fibrils to a transmissible prion disease.

    Directory of Open Access Journals (Sweden)

    Natallia Makarava

    2011-12-01

    Full Text Available The transmissible agent of prion disease consists of a prion protein in its abnormal, β-sheet rich state (PrP(Sc, which is capable of replicating itself according to the template-assisted mechanism. This mechanism postulates that the folding pattern of a newly recruited polypeptide chain accurately reproduces that of a PrP(Sc template. Here we report that authentic PrP(Sc and transmissible prion disease can be generated de novo in wild type animals by recombinant PrP (rPrP amyloid fibrils, which are structurally different from PrP(Sc and lack any detectable PrP(Sc particles. When induced by rPrP fibrils, a long silent stage that involved two serial passages preceded development of the clinical disease. Once emerged, the prion disease was characterized by unique clinical, neuropathological, and biochemical features. The long silent stage to the disease was accompanied by significant transformation in neuropathological properties and biochemical features of the proteinase K-resistant PrP material (PrPres before authentic PrP(Sc evolved. The current work illustrates that transmissible prion diseases can be induced by PrP structures different from that of authentic PrP(Sc and suggests that a new mechanism different from the classical templating exists. This new mechanism designated as "deformed templating" postulates that a change in the PrP folding pattern from the one present in rPrP fibrils to an alternative specific for PrP(Sc can occur. The current work provides important new insight into the mechanisms underlying genesis of the transmissible protein states and has numerous implications for understanding the etiology of neurodegenerative diseases.

  7. Donepezil loaded PLGA-b-PEG nanoparticles: their ability to induce destabilization of amyloid fibrils and to cross blood brain barrier in vitro.

    Science.gov (United States)

    Baysal, Ipek; Ucar, Gulberk; Gultekinoglu, Merve; Ulubayram, Kezban; Yabanoglu-Ciftci, Samiye

    2017-01-01

    Alzheimer's disease (AD) is a progressive and irreversible neurodegenerative disease. Cholinesterase inhibitors (ChEIs) are commonly used for symptomatic treatment of neural transmission improvement in AD. Donepezil is a reversible and non-competitive ChEI which is clinically used for palliative treatment of AD. The aim of the present study was to investigate the destabilizing effect of donepezil loaded poly(lactic-co-glycolic acid)-block-poly (ethylene glycol) [PLGA-b-PEG] nanoparticles on fibril formation in vitro and the ability of these nanoparticles to cross blood brain barrier (BBB) using in vitro BBB model and the neuroprotective effects of free donepezil and donepezil loaded PLGA-b-PEG nanoparticles. Donepezil loaded PLGA-b-PEG nanoparticles were prepared with double emulsion method. Destabilizing effect of these donepezil loaded particles on the amyloid-beta fibril (Aβ 1-40 and Aβ 1-42 ) formation was determined in vitro. Nanoparticles were found to have small particle size and have destabilizing effect on fibril formation. In vitro BBB model was successfully prepared. Nanoparticles showed the ability to cross the BBB and showed a controlled release profile in this system. IL-1β, IL-6, GM-CSF, TGF-β, MCP-1 and TNF-α levels were found to be increased in both gene and protein expression levels in astrocytes incubated with amyloid fibrils in in vitro BBB model suggesting an increased inflammation. Free donepezil and donepezil loaded nanoparticle administration caused a significant dose-dependent decrease in both gene and protein expression levels of IL-1β, IL-6, GM-CSF and TNF-α. No significant changes were observed for TGF-β and MCP-1.

  8. Effect of heating on the stability of amyloid A (AA) fibrils and the intra- and cross-species transmission of AA amyloidosis.

    Science.gov (United States)

    Ogawa, Saki; Murakami, Tomoaki; Inoshima, Yasuo; Ishiguro, Naotaka

    2015-01-01

    Amyloid A (AA) amyloidosis is a protein misfolding disease characterized by extracellular deposition of AA fibrils. AA fibrils are found in several tissues from food animals with AA amyloidosis. For hygienic purposes, heating is widely used to inactivate microbes in food, but it is uncertain whether heating is sufficient to inactivate AA fibrils and prevent intra- or cross-species transmission. We examined the effect of heating (at 60 °C or 100 °C) and autoclaving (at 121 °C or 135 °C) on murine and bovine AA fibrils using Western blot analysis, transmission electron microscopy (TEM), and mouse model transmission experiments. TEM revealed that a mixture of AA fibrils and amorphous aggregates appeared after heating at 100 °C, whereas autoclaving at 135 °C produced large amorphous aggregates. AA fibrils retained antigen specificity in Western blot analysis when heated at 100 °C or autoclaved at 121 °C, but not when autoclaved at 135 °C. Transmissible pathogenicity of murine and bovine AA fibrils subjected to heating (at 60 °C or 100 °C) was significantly stimulated and resulted in amyloid deposition in mice. Autoclaving of murine AA fibrils at 121 °C or 135 °C significantly decreased amyloid deposition. Moreover, amyloid deposition in mice injected with murine AA fibrils was more severe than that in mice injected with bovine AA fibrils. Bovine AA fibrils autoclaved at 121 °C or 135 °C did not induce amyloid deposition in mice. These results suggest that AA fibrils are relatively heat stable and that similar to prions, autoclaving at 135 °C is required to destroy the pathogenicity of AA fibrils. These findings may contribute to the prevention of AA fibril transmission through food materials to different animals and especially to humans.

  9. Final Project Report Load Modeling Transmission Research

    Energy Technology Data Exchange (ETDEWEB)

    Lesieutre, Bernard [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Bravo, Richard [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Yinger, Robert [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Chassin, Dave [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Huang, Henry [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Lu, Ning [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Hiskens, Ian [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Venkataramanan, Giri [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2012-03-31

    The research presented in this report primarily focuses on improving power system load models to better represent their impact on system behavior. The previous standard load model fails to capture the delayed voltage recovery events that are observed in the Southwest and elsewhere. These events are attributed to stalled air conditioner units after a fault. To gain a better understanding of their role in these events and to guide modeling efforts, typical air conditioner units were testing in laboratories. Using data obtained from these extensive tests, new load models were developed to match air conditioner behavior. An air conditioner model is incorporated in the new WECC composite load model. These models are used in dynamic studies of the West and can impact power transfer limits for California. Unit-level and systemlevel solutions are proposed as potential solutions to the delayed voltage recovery problem.

  10. Centralized Coordination of Load Shedding & Protection System of Transmission Lines

    DEFF Research Database (Denmark)

    Hoseinzadeh, Bakhtyar; Bak, Claus Leth

    2018-01-01

    The power system integrity is vulnerable to thermal limit of transmission lines due to overloading and consequently activation of their protection devices following severe contingencies. In this paper, the loading rate of transmission lines is monitored online and is considered in the centralized......, over current protection....

  11. Loading algorithms for subband coded image transmission using multicarrier modulation

    Science.gov (United States)

    Zheng, Haito; Liu, Kuo Juey R.

    1998-12-01

    We present a new parallel framework for multimedia data transmission over spectrally shaped channels using multicarrier modulation. Source images are first decomposed into a set of layers with different perceptual importance. Unlike the traditional approaches, the layers are transmitted simultaneously, each occupying a number of subchannels. We develop parallel loading algorithms which distribute the transmitted power and data rate among the subchannels efficiently, to provide unequal error protection. A power optimized serial transmission system is also developed. Simulation results show that the parallel transmission system achieve significant performance improvement compared to the optimized serial transmission and the existing loading algorithms developed for data transmission. Performance comparison under different parameters are also presented. The proposed algorithms are well suited for both Additive Gaussian White Noise (AGWN) channels and spectrally shaped channels which are typical in ADSL systems. Numerical comparison for different parameters are also given.

  12. Collagen Fibrils and Proteoglycans of Macular Dystrophy Cornea: Ultrastructure and 3D Transmission Electron Tomography.

    Science.gov (United States)

    Akhtar, Saeed; Alkatan, Hind M; Kirat, Omar; Khan, Adnan A; Almubrad, Turki

    2015-06-01

    We report the ultrastructure and 3D transmission electron tomography of collagen fibrils (CFs), proteoglycans (PGs), and microfibrils within the CF of corneas of patients with macular corneal dystrophy (MCD). Three normal corneas and three MCD corneas from three Saudi patients (aged 25, 31, and 49 years, respectively) were used for this study. The corneas were processed for light and electron microscopy studies. 3D images were composed from a set of 120 ultrastructural images using the program "Composer" and visualized using the program "Visuliser Kai". 3D image analysis of MCD cornea showed a clear organization of PGs around the CF at very high magnification and degeneration of the microfibrils within the CF. Within the MCD cornea, the PG area in the anterior stroma was significantly larger than in the middle and posterior stroma. The PG area in the MCD cornea was significantly larger compared with the PG area in the normal cornea. The CF diameter and inter-fibrillar spacing of the MCD cornea were significantly smaller compared with those of the normal cornea. Ultrastructural 3D imaging showed that the production of unsulfated keratin sulfate (KS) may lead to the degeneration of micro-CFs within the CFs. The effect of the unsulfated KS was higher in the anterior stroma compared with the posterior stroma.

  13. Monitoring in vivo load transmission through an external fixator.

    Science.gov (United States)

    Grasa, J; Gómez-Benito, M J; González-Torres, L A; Asiaín, D; Quero, F; García-Aznar, J M

    2010-03-01

    This work presents a portable non-invasive external fixator to assess and monitor fracture healing in real time. To evaluate the potential of this fixator, a transverse osteotomy was performed in the tibia of six adult sheep (mean age 3+/-0.5 years and weight 63+/-5 kg). The fractures were stabilized by a specially designed unilateral external fixator, which was instrumented by means of a set of strain gauges. Strains in the external surface of the fixator were monitored during all the healing process. A wireless, remote monitoring of the implant was developed through a specially designed external telemetric device. The strain gauges were arranged in two different half-bridge Wheatstone configurations, allowing easy post-processing of the signal. Thus, bending loads were measured in two planes of the external fixator acting as a load cell. The load through the fixator was evaluated for the gait cycle during all the healing process. Full weight bearing of the injured leg was observed from the beginning. The load transmission mechanism in the fixator was quite similar in all operated tibias and radiographic images showed a successful healing in all animals. Although the fixator has only been tested in an animal model, after further testing this system may have clinical potential.

  14. Minerals and aligned collagen fibrils in tilapia fish scales: structural analysis using dark-field and energy-filtered transmission electron microscopy and electron tomography.

    Science.gov (United States)

    Okuda, Mitsuhiro; Ogawa, Nobuhiro; Takeguchi, Masaki; Hashimoto, Ayako; Tagaya, Motohiro; Chen, Song; Hanagata, Nobutaka; Ikoma, Toshiyuki

    2011-10-01

    The mineralized structure of aligned collagen fibrils in a tilapia fish scale was investigated using transmission electron microscopy (TEM) techniques after a thin sample was prepared using aqueous techniques. Electron diffraction and electron energy loss spectroscopy data indicated that a mineralized internal layer consisting of aligned collagen fibrils contains hydroxyapatite crystals. Bright-field imaging, dark-field imaging, and energy-filtered TEM showed that the hydroxyapatite was mainly distributed in the hole zones of the aligned collagen fibrils structure, while needle-like materials composed of calcium compounds including hydroxyapatite existed in the mineralized internal layer. Dark-field imaging and three-dimensional observation using electron tomography revealed that hydroxyapatite and needle-like materials were mainly found in the matrix between the collagen fibrils. It was observed that hydroxyapatite and needle-like materials were preferentially distributed on the surface of the hole zones in the aligned collagen fibrils structure and in the matrix between the collagen fibrils in the mineralized internal layer of the scale.

  15. Out-of-plane orientation of cellulose elementary fibrils on spruce tracheid wall based on imaging with high-resolution transmission electron microscopy.

    Science.gov (United States)

    Reza, Mehedi; Ruokolainen, Janne; Vuorinen, Tapani

    2014-09-01

    A 3D model of the tracheid wall has been proposed based on high-resolution cryo-TEM where, in contrast to the current understanding, the cellulose elementary fibrils protrude from the cell wall plane. The ultrastructure of the tracheid walls of Picea abies was examined through imaging of ultrathin radial, tangential and transverse sections of wood by transmission electron microscopy and with digital image processing. It was found that the elementary fibrils (EFs) of cellulose were rarely deposited in the plane of the concentric cell wall layers, in contrast to the current understanding. In addition to the adopted concept of longitudinal fibril angle, EFs protruded from the cell wall plane in varying angles depending on the layer. Moreover, the out-of-plane fibril angle varied between radial and tangential walls. In the tangential S2 layers, EFs were always out-of-plane whereas planar orientation was typical for the S2 layer in radial walls. The pattern of protruding EFs was evident in almost all axial and transverse images of the S1 layer. Similar out-of-plane orientation was found in the transverse sections of the S3 layer. A new model of the tracheid wall with EF orientation is presented as a summary of this study. The outcome of this study will enhance our understanding of the elementary fibril orientation in the tracheid wall.

  16. STRESS LOADING SIMULATION OF HYDRO-MECHANICAL TRANSMISSION OF DUMP TRUCK

    Directory of Open Access Journals (Sweden)

    S. A. Sidorov

    2006-01-01

    Full Text Available The Transmission model and software package to investigate stress loading of a hydromechanical transmission of a dump truck have been developed. The given software package allows to model stress loading of transmission gears in taking-off and acceleration modes at various road resistance, positions of an engine control pedal and initial revolutions of an engine crankshaft, various laws of friction clutch switching and some other parameters that permit to reveal a rate of various operational mode influence on stress loading of a dump truck transmission. An equivalence of the developed software is proved by the comparison of the experimentally obtained stress loading process of the hydro-mechanical transmission of a BelAZ- 7555 dump truck with the results of the simulation 

  17. Pressure transmission area and maximum pressure transmission of different thermoplastic resin denture base materials under impact load.

    Science.gov (United States)

    Nasution, Hubban; Kamonkhantikul, Krid; Arksornnukit, Mansuang; Takahashi, Hidekazu

    2018-01-01

    The purposes of the present study were to examine the pressure transmission area and maximum pressure transmission of thermoplastic resin denture base materials under an impact load, and to evaluate the modulus of elasticity and nanohardness of thermoplastic resin denture base. Three injection-molded thermoplastic resin denture base materials [polycarbonate (Basis PC), ethylene propylene (Duraflex), and polyamide (Valplast)] and one conventional heat-polymerized acrylic resin (PMMA, SR Triplex Hot) denture base, all with a mandibular first molar acrylic resin denture tooth set in were evaluated (n=6). Pressure transmission area and maximum pressure transmission of the specimens under an impact load were observed by using pressure-sensitive sheets. The modulus of elasticity and nanohardness of each denture base (n=10) were measured on 15×15×15×3mm 3 specimen by using an ultramicroindentation system. The pressure transmission area, modulus of elasticity, and nanohardness data were statistically analyzed with 1-way ANOVA, followed by Tamhane or Tukey HSD post hoc test (α=.05). The maximum pressure transmission data were statistically analyzed with Kruskal-Wallis H test, followed by Mann-Whitney U test (α=.05). Polymethyl methacrylate showed significantly larger pressure transmission area and higher maximum pressure transmission than the other groups (Pdenture bases (Pthermoplastic resin denture base materials. Differences in the modulus of elasticity and nanohardness of each type of denture base were demonstrated. Copyright © 2017 Japan Prosthodontic Society. Published by Elsevier Ltd. All rights reserved.

  18. Avalanche transmission and critical behaviour in load-bearing ...

    Indian Academy of Sciences (India)

    The strength and stability properties of hierarchical load-bearing networks and their strengthened variants have been discussed in a recent work. Here, we study the avalanche time distributions on these load-bearing networks. The avalanche time distributions of the V-lattice, a unique realization of the networks, show ...

  19. Load management alternatives to transmission and distribution construction: Toledo-Wren case study

    Energy Technology Data Exchange (ETDEWEB)

    Englin, J.E.; Klan, M.S.; Lyke, A.J.; Tawil, J.J.; De Steese, J.G.; Tepel, R.C.

    1987-12-01

    This paper describes the development of a method to predict the feasibility of using load management as an alternative to construction of transmission and distribution capacity. A forecasting model was developed and applied to a particular case. Several problems were identified in the test case, necessitating modification of the model. The authors conclude that the modified version of the model allows accurate assessment of the effects of load management and conservation measures on transmission capacity. 13 figs. (JDH)

  20. A Beacon Transmission Power Control Algorithm Based on Wireless Channel Load Forecasting in VANETs.

    Science.gov (United States)

    Mo, Yuanfu; Yu, Dexin; Song, Jun; Zheng, Kun; Guo, Yajuan

    2015-01-01

    In a vehicular ad hoc network (VANET), the periodic exchange of single-hop status information broadcasts (beacon frames) produces channel loading, which causes channel congestion and induces information conflict problems. To guarantee fairness in beacon transmissions from each node and maximum network connectivity, adjustment of the beacon transmission power is an effective method for reducing and preventing channel congestion. In this study, the primary factors that influence wireless channel loading are selected to construct the KF-BCLF, which is a channel load forecasting algorithm based on a recursive Kalman filter and employs multiple regression equation. By pre-adjusting the transmission power based on the forecasted channel load, the channel load was kept within a predefined range; therefore, channel congestion was prevented. Based on this method, the CLF-BTPC, which is a transmission power control algorithm, is proposed. To verify KF-BCLF algorithm, a traffic survey method that involved the collection of floating car data along a major traffic road in Changchun City is employed. By comparing this forecast with the measured channel loads, the proposed KF-BCLF algorithm was proven to be effective. In addition, the CLF-BTPC algorithm is verified by simulating a section of eight-lane highway and a signal-controlled urban intersection. The results of the two verification process indicate that this distributed CLF-BTPC algorithm can effectively control channel load, prevent channel congestion, and enhance the stability and robustness of wireless beacon transmission in a vehicular network.

  1. A Beacon Transmission Power Control Algorithm Based on Wireless Channel Load Forecasting in VANETs.

    Directory of Open Access Journals (Sweden)

    Yuanfu Mo

    Full Text Available In a vehicular ad hoc network (VANET, the periodic exchange of single-hop status information broadcasts (beacon frames produces channel loading, which causes channel congestion and induces information conflict problems. To guarantee fairness in beacon transmissions from each node and maximum network connectivity, adjustment of the beacon transmission power is an effective method for reducing and preventing channel congestion. In this study, the primary factors that influence wireless channel loading are selected to construct the KF-BCLF, which is a channel load forecasting algorithm based on a recursive Kalman filter and employs multiple regression equation. By pre-adjusting the transmission power based on the forecasted channel load, the channel load was kept within a predefined range; therefore, channel congestion was prevented. Based on this method, the CLF-BTPC, which is a transmission power control algorithm, is proposed. To verify KF-BCLF algorithm, a traffic survey method that involved the collection of floating car data along a major traffic road in Changchun City is employed. By comparing this forecast with the measured channel loads, the proposed KF-BCLF algorithm was proven to be effective. In addition, the CLF-BTPC algorithm is verified by simulating a section of eight-lane highway and a signal-controlled urban intersection. The results of the two verification process indicate that this distributed CLF-BTPC algorithm can effectively control channel load, prevent channel congestion, and enhance the stability and robustness of wireless beacon transmission in a vehicular network.

  2. Real Time Load Optimisation of Cable Based Transmission Grids

    DEFF Research Database (Denmark)

    Olsen, Rasmus Schmidt; Holbøll, Joachim; Guðmundsdottir, Unnur Stella

    2011-01-01

    Energinet.dk has launched an investigation of dynamic current ratings of cable based transmission grids, where both internal and external parameters are variables. The first topic was to investigate state of the art within calculating the current carrying capacity (ampacity or loadability) of cab...

  3. A Hybrid LCC-VSC HVDC Transmission System Supplying a Passive Load

    Science.gov (United States)

    Kotb, Omar

    High Voltage Direct Current (HVDC) transmission systems continue to be an excellent asset in modern power systems, mainly for their ability to overcome the problems of AC transmission, such as the interconnection of asynchronous grids, stability of long transmission lines, and use of long cables for power transmission. In the past 20 years, Voltage Source Converter (VSC)-HVDC transmission systems were developed and installed in many projects, thereby adding more operational benefits to DC transmission option, such as high controllability, ability to supply weak networks, and reduced converter reactive power demand. Nevertheless, VSC-HVDC transmission suffers from the disadvantages of high losses and cost. In this research, a hybrid HVDC employing a Line Commutated Converter (LCC) as rectifier and a VSC as inverter is used to supply a passive network through a DC cable. The hybrid system is best suited for unidirectional power transmission scenarios, such as power transmission to islands and remote load centers, where the construction of new transmission lines is prohibitively expensive. Control modes for the rectifier and inverter are selected and implemented using Proportional Integral (PI) controllers. Special control schemes are developed for abnormal operating conditions such as starting at light load and recovering from AC network faults. The system performance under steady state and transient conditions is investigated by EMTP-RV simulations. The results show the feasibility of the hybrid system.

  4. Load-Sharing Characteristics of Power-Split Transmission System Based on Deformation Compatibility and Loaded Tooth Contact Analysis

    Directory of Open Access Journals (Sweden)

    Hao Dong

    2015-01-01

    Full Text Available In order to implement the uniform load distribution of the power-split transmission system, a pseudostatic model is built. Based on the loaded tooth contact analysis (LTCA technique, the actual meshing process of each gear pair is simulated and the fitting curve of time-varying mesh stiffness is obtained. And then, the torsional angle deformation compatibility conditions are proposed according to the closed-loop characteristic of power flow, which will be combined with the torque equilibrium conditions and elastic support conditions to calculate the transfer torque of each gear pair. Finally, the load-sharing coefficient of the power-split transmission system is obtained, and the influences of the installation errors are analyzed. The results show that the above-mentioned installation errors comprehensively influence the load-sharing characteristics, and the reduction of only one error could not effectively achieve perfect load-sharing characteristics. Allowing for the spline clearance floating and constrained by the radial spacing ring, the influence of the floating pinion is analyzed. It shows that the floating pinion can improve the load-sharing characteristics. Through the comparison between the theoretical and related experimental data, the reasonability and feasibility of the above-proposed method and model are verified.

  5. Ameliorating Amyloid-β Fibrils Triggered Inflammation via Curcumin-Loaded Polymeric Nanoconstructs

    Directory of Open Access Journals (Sweden)

    Andrea Ameruoso

    2017-10-01

    Full Text Available Inflammation is a common hallmark in several diseases, including atherosclerosis, cancer, obesity, and neurodegeneration. In Alzheimer’s disease (AD, growing evidence directly correlates neuronal damage with inflammation of myeloid brain cells, such as microglia. Here, polymeric nanoparticles were engineered and characterized for the delivery of anti-inflammatory molecules to macrophages stimulated via direct incubation with amyloid-β fibers. 200 nm spherical polymeric nanoconstructs (SPNs and 1,000 nm discoidal polymeric nanoconstructs (DPNs were synthesized using poly(lactic-co-glycolic acid (PLGA, polyethylene glycol (PEG, and lipid chains as building blocks. First, the internalization propensity in macrophages of both nanoparticles was assessed via cytofluorimetric and confocal microscopy analyses, demonstrating that SPNs are by far more rapidly taken up as compared to DPNs (99.6 ± 0.11 vs 14.4 ± 0.06%, within 24 h. Then, Curcumin-loaded SPNs (Curc-SPNs were realized by encapsulating Curcumin, a natural anti-inflammatory molecule, within the PLGA core of SPNs. Finally, Curc-SPNs were shown to diminish up to 6.5-fold the production of pro-inflammatory cytokines—IL-1β; IL-6, and TNF-α—in macrophages stimulated via amyloid-β fibers. Although more sophisticated in vitro models and systematic analyses on the blood–brain barrier permeability are critically needed, these findings hold potential in the development of nanoparticles for modulating inflammation in AD.

  6. Symmetry-Related Electromagnetic Properties of Resonator-Loaded Transmission Lines and Applications

    Directory of Open Access Journals (Sweden)

    Jordi Naqui

    2015-05-01

    Full Text Available This paper reviews the recent progress in the analysis and applications of the symmetry-related electromagnetic properties of transmission lines loaded with symmetric configurations of resonant elements. It will be shown that the transmission characteristics of these reactively loaded lines can be controlled by the relative orientation between the line and the resonant elements. Two main types of loaded lines are considered: (i resonance-based structures; and (ii frequency-splitting structures. In resonance-based transmission lines, a line is loaded with a single resonant (and symmetric element. For a perfectly symmetric structure, the line is transparent if the line and resonator exhibit symmetry planes of different electromagnetic nature (electric or magnetic wall, whereas the line exhibits a notch (resonance in the transmission coefficient if the symmetry planes behave as either electric or magnetic walls (symmetric configuration, or if symmetry is broken. In frequency-splitting lines, paired resonators are typically loaded to the transmission line; the structure exhibits a single notch for the symmetric configuration, whereas generally two split notches appear when symmetry is disrupted. Applications of these structures include microwave sensors (e.g., contactless sensors of spatial variables, selective mode suppressors (of application in common-mode suppressed differential lines, for instance and spectral signature barcodes, among others.

  7. Analysis of transmission lines loaded with pairs of coupled resonant elements and application to sensors

    Energy Technology Data Exchange (ETDEWEB)

    Naqui, J.; Su, L., E-mail: lijuan.suri.su@gmail.com; Mata, J.; Martín, F., E-mail: Ferran.Martin@uab.es

    2015-06-01

    This paper is focused on the analysis of transmission lines loaded with pairs of magnetically coupled resonators. We have considered two different structures: (i) a microstrip line loaded with pairs of stepped impedance resonators (SIRs), and (ii) a coplanar waveguide (CPW) transmission line loaded with pairs of split ring resonators (SRRs). In both cases, the line exhibits a single resonance frequency (transmission zero) if the resonators are identical (symmetric structure with regard to the line axis), and this resonance is different to the one of the line loaded with a single resonator due to inter-resonator coupling. If the structures are asymmetric, inter-resonator coupling enhances the distance between the two split resonance frequencies that arise. In spite that the considered lines and loading resonators are very different and are described by different lumped element equivalent circuit models, the phenomenology associated to the effects of coupling is exactly the same, and the resonance frequencies are given by identical expressions. The reported lumped element circuit models of both structures are validated by comparing the circuit simulations with extracted parameters with both electromagnetic simulations and experimental data. These structures can be useful for the implementation of microwave sensors based on symmetry properties. - Highlights: • Magnetic-coupling between resonant elements affects transmission properties. • Inter-resonant coupling enhances the distance of two resonant frequencies. • The structures are useful for sensors and comparators, etc.

  8. Nonlinear Seismic Behavior of Different Boundary Conditions of Transmission Line Systems under Earthquake Loading

    Directory of Open Access Journals (Sweden)

    Li Tian

    2016-01-01

    Full Text Available Nonlinear seismic behaviors of different boundary conditions of transmission line system under earthquake loading are investigated in this paper. The transmission lines are modeled by cable element accounting for the nonlinearity of the cable. For the suspension type, three towers and two span lines with spring model (Model 1 and three towers and four span lines’ model (Model 2 are established, respectively. For the tension type, three towers and two span lines’ model (Model 3 and three towers and four span lines’ model (Model 4 are created, respectively. The frequencies of the transmission towers and transmission lines of the suspension type and tension type are calculated, respectively. The responses of the suspension type and tension type are investigated using nonlinear time history analysis method, respectively. The results show that the responses of the transmission tower and transmission line of the two models of the suspension type are slightly different. However, the responses of transmission tower and transmission line of the two models of the tension type are significantly different. Therefore, in order to obtain accurate results, a reasonable model should be considered. The results could provide a reference for the seismic analysis of the transmission tower-line system.

  9. Antiretroviral treatment, viral load of mothers & perinatal HIV transmission in Mumbai, India

    Directory of Open Access Journals (Sweden)

    Swati P Ahir

    2013-01-01

    Full Text Available Background & objectives: Mother-to-child transmission (MTCT is the most significant route of HIV transmission in children below the age of 15 yr. In India, perinatal HIV transmission, even after treatment, accounts for 5.4 per cent of HIV cases. The present study was conducted to evaluate the efficacy of anti-retro viral therapy (ART or prophylactic treatment (PT to control maternal viral load in HIV positive women, and its effect on vertical HIV transmission to their infants. Methods: A total of 58 HIV positive women were enrolled at the time of delivery and their plasma samples were obtained within 24 h of delivery for estimation of viral load. Viral load analysis was completed in 38 women. Infants received single dose nevirapine within 2 h of birth and zidovudine for 6 wk. At the end of 18 month follow up, HIV positive or negative status was available in 28 infants. Results: Results revealed undetectable levels of viral load in 58.3 per cent of women with ART compared to 30.7 per cent of women with PT. No women on ART had viral load more than 10,000 copies/ml, whereas seven (26.9%, P=0.07 women receiving PT had this viral load. Median CD4 count of women on PT (483 cells/μl was high compared to the women on ART (289 cells/ μl. At the end of 18 months follow up, only two children were HIV positive, whose mothers were on PT. One had in utero transmission; infection detected within 48 h of delivery, while the other child was infected post partum as HIV was detected at six months follow up. Interpretation & conclusions: Women who received a single dose of nevirapine during delivery had higher levels of viral load than women on ART. Combination drug therapy for pregnant women is now a standard of care in most of the western countries; use of nevirapine monotherapy at the time of delivery in our settings is not effective in controlling viral load. This highlights initiation of ART in pregnant women to control their viral load and thus to inhibit

  10. Data transmission in long-range dielectric-loaded surface plasmon polariton waveguides

    DEFF Research Database (Denmark)

    Kharitonov, S.; Kiselev, R.; Kumar, Ashwani

    2014-01-01

    We demonstrate the data transmission of 10 Gbit/s on-off keying modulated 1550 nm signal through a long-range dielectric-loaded surface plasmon polariton waveguide structure with negligible signal degradation. In the experiment the bit error rate penalties do not exceed 0.6 dB over the 15 nm...

  11. L2-LBMT: A Layered Load Balance Routing Protocol for underwater multimedia data transmission

    Science.gov (United States)

    Lv, Ze; Tang, Ruichun; Tao, Ye; Sun, Xin; Xu, Xiaowei

    2017-12-01

    Providing highly efficient underwater transmission of mass multimedia data is challenging due to the particularities of the underwater environment. Although there are many schemes proposed to optimize the underwater acoustic network communication protocols, from physical layer, data link layer, network layer to transport layer, the existing routing protocols for underwater wireless sensor network (UWSN) still cannot well deal with the problems in transmitting multimedia data because of the difficulties involved in high energy consumption, low transmission reliability or high transmission delay. It prevents us from applying underwater multimedia data to real-time monitoring of marine environment in practical application, especially in emergency search, rescue operation and military field. Therefore, the inefficient transmission of marine multimedia data has become a serious problem that needs to be solved urgently. In this paper, A Layered Load Balance Routing Protocol (L2-LBMT) is proposed for underwater multimedia data transmission. In L2-LBMT, we use layered and load-balance Ad Hoc Network to transmit data, and adopt segmented data reliable transfer (SDRT) protocol to improve the data transport reliability. And a 3-node variant of tornado (3-VT) code is also combined with the Ad Hoc Network to transmit little emergency data more quickly. The simulation results show that the proposed protocol can balance energy consumption of each node, effectively prolong the network lifetime and reduce transmission delay of marine multimedia data.

  12. Fracture mechanics of collagen fibrils

    DEFF Research Database (Denmark)

    Svensson, Rene B; Mulder, Hindrik; Kovanen, Vuokko

    2013-01-01

    technique to measure the mechanical behavior of individual collagen fibrils loaded to failure. Fibrils from human patellar tendons, rat-tail tendons (RTTs), NaBH₄ reduced RTTs, and tail tendons of Zucker diabetic fat rats were tested. We found a characteristic three-phase stress-strain behavior in the human...... and the plateau continued until failure. The importance of cross-link lability was investigated by NaBH₄ reduction of the rat-tail fibrils, which did not alter their behavior. These findings shed light on the function of cross-links at the fibril level, but further studies will be required to establish...

  13. Assessment of Embedded Conjugated Polymer Sensor Arrays for Potential Load Transmission Measurement in Orthopaedic Implants.

    Science.gov (United States)

    Micolini, Carolina; Holness, Frederick Benjamin; Johnson, James A; Price, Aaron David

    2017-11-29

    Load transfer through orthopaedic joint implants is poorly understood. The longer-term outcomes of these implants are just starting to be studied, making it imperative to monitor contact loads across the entire joint implant interface to elucidate the force transmission and distribution mechanisms exhibited by these implants in service. This study proposes and demonstrates the design, implementation, and characterization of a 3D-printed smart polymer sensor array using conductive polyaniline (PANI) structures embedded within a polymeric parent phase. The piezoresistive characteristics of PANI were investigated to characterize the sensing behaviour inherent to these embedded pressure sensor arrays, including the experimental determination of the stable response of PANI to continuous loading, stability throughout the course of loading and unloading cycles, and finally sensor repeatability and linearity in response to incremental loading cycles. This specially developed multi-material additive manufacturing process for PANI is shown be an attractive approach for the fabrication of implant components having embedded smart-polymer sensors, which could ultimately be employed for the measurement and analysis of joint loads in orthopaedic implants for in vitro testing.

  14. Assessment of Embedded Conjugated Polymer Sensor Arrays for Potential Load Transmission Measurement in Orthopaedic Implants

    Directory of Open Access Journals (Sweden)

    Carolina Micolini

    2017-11-01

    Full Text Available Load transfer through orthopaedic joint implants is poorly understood. The longer-term outcomes of these implants are just starting to be studied, making it imperative to monitor contact loads across the entire joint implant interface to elucidate the force transmission and distribution mechanisms exhibited by these implants in service. This study proposes and demonstrates the design, implementation, and characterization of a 3D-printed smart polymer sensor array using conductive polyaniline (PANI structures embedded within a polymeric parent phase. The piezoresistive characteristics of PANI were investigated to characterize the sensing behaviour inherent to these embedded pressure sensor arrays, including the experimental determination of the stable response of PANI to continuous loading, stability throughout the course of loading and unloading cycles, and finally sensor repeatability and linearity in response to incremental loading cycles. This specially developed multi-material additive manufacturing process for PANI is shown be an attractive approach for the fabrication of implant components having embedded smart-polymer sensors, which could ultimately be employed for the measurement and analysis of joint loads in orthopaedic implants for in vitro testing.

  15. Recent Enhancements to the NASA Langley Structural Acoustics Loads and Transmission (SALT) Facility

    Science.gov (United States)

    Rizzi, Stephen A.; Cabell, Randolph H.; Allen, Albert R.

    2013-01-01

    The Structural Acoustics Loads and Transmission (SALT) facility at the NASA Langley Research Center is comprised of an anechoic room and a reverberant room, and may act as a transmission loss suite when test articles are mounted in a window connecting the two rooms. In the latter configuration, the reverberant room acts as the noise source side and the anechoic room as the receiver side. The noise generation system used for qualification testing in the reverberant room was previously shown to achieve a maximum overall sound pressure level of 141 dB. This is considered to be marginally adequate for generating sound pressure levels typically required for launch vehicle payload qualification testing. Recent enhancements to the noise generation system increased the maximum overall sound pressure level to 154 dB, through the use of two airstream modulators coupled to 35 Hz and 160 Hz horns. This paper documents the acoustic performance of the enhanced noise generation system for a variety of relevant test spectra. Additionally, it demonstrates the capability of the SALT facility to conduct transmission loss and absorption testing in accordance with ASTM and ISO standards, respectively. A few examples of test capabilities are shown and include transmission loss testing of simple unstiffened and built up structures and measurement of the diffuse field absorption coefficient of a fibrous acoustic blanket.

  16. Study of a conceptual nuclear energy center at Green River, Utah. Power demand, load center assessment and transmission

    International Nuclear Information System (INIS)

    Smith, D.R.; Thaik, A.; Pingel, P.

    1982-02-01

    This document constitutes a segment of a feasibility study investigating the ramification of constructing a nuclear energy center in an arid western region. In this phase of the study. The projected power demands and load center locations were reviewed and assessed. Alternative transmission systems were analysed and a conceptual transmission for bulk power transportation is proposed with potential line routes. Environmental impacts of the proposed transmission were also identified

  17. Study of a conceptual nuclear energy center at Green River, Utah. Power demand, load center assessment and transmission

    Energy Technology Data Exchange (ETDEWEB)

    Smith, D.R.; Thaik, A.; Pingel, P.

    1982-02-01

    This document constitutes a segment of a feasibility study investigating the ramification of constructing a nuclear energy center in an arid western region. In this phase of the study. The projected power demands and load center locations were reviewed and assessed. Alternative transmission systems were analysed and a conceptual transmission for bulk power transportation is proposed with potential line routes. Environmental impacts of the proposed transmission were also identified.

  18. Impacts of rising air temperatures on electric transmission ampacity and peak electricity load in the United States

    Science.gov (United States)

    Bartos, Matthew; Chester, Mikhail; Johnson, Nathan; Gorman, Brandon; Eisenberg, Daniel; Linkov, Igor; Bates, Matthew

    2016-11-01

    Climate change may constrain future electricity supply adequacy by reducing electric transmission capacity and increasing electricity demand. The carrying capacity of electric power cables decreases as ambient air temperatures rise; similarly, during the summer peak period, electricity loads typically increase with hotter air temperatures due to increased air conditioning usage. As atmospheric carbon concentrations increase, higher ambient air temperatures may strain power infrastructure by simultaneously reducing transmission capacity and increasing peak electricity load. We estimate the impacts of rising ambient air temperatures on electric transmission ampacity and peak per-capita electricity load for 121 planning areas in the United States using downscaled global climate model projections. Together, these planning areas account for roughly 80% of current peak summertime load. We estimate climate-attributable capacity reductions to transmission lines by constructing thermal models of representative conductors, then forcing these models with future temperature projections to determine the percent change in rated ampacity. Next, we assess the impact of climate change on electricity load by using historical relationships between ambient temperature and utility-scale summertime peak load to estimate the extent to which climate change will incur additional peak load increases. We find that by mid-century (2040-2060), increases in ambient air temperature may reduce average summertime transmission capacity by 1.9%-5.8% relative to the 1990-2010 reference period. At the same time, peak per-capita summertime loads may rise by 4.2%-15% on average due to increases in ambient air temperature. In the absence of energy efficiency gains, demand-side management programs and transmission infrastructure upgrades, these load increases have the potential to upset current assumptions about future electricity supply adequacy.

  19. Wind-induced transmission tower foundation loads. A field study-design code comparison

    Energy Technology Data Exchange (ETDEWEB)

    Savory, E. [Department of Mechanical and Materials Engineering, University of Western Ontario, London, Ont. (Canada); Parke, G.A.R.; Disney, P.; Toy, N. [School of Engineering, University of Surrey, Guildford, Surrey GU2 7XH (United Kingdom)

    2008-06-15

    This paper presents a comparison between the wind-induced foundation loads measured on a type L6 transmission line tower during a field study in the UK and those computed using the UK Code of Practice for lattice tower and transmission line design (BS8100). In this work, the Code provisions have been generalised to give the wind-induced strain in each of the tower legs immediately above the foundation as a function of wind direction and wind speed at the top of the tower. The complete data set from the field monitoring has been decomposed to provide a similar formulation for comparison purposes. The analysis shows excellent agreement between the Code calculations and the measured results, within the overall accuracy of the field data. This indicates that, at least for the tower type examined here, the existing design Code provides a reliable transformation of the local wind speed at the top of the tower into tension and compression loads on the foundations. (author)

  20. Power transfer capability assessment of transmission interfaces with SVC and load shedding systems

    Energy Technology Data Exchange (ETDEWEB)

    Pavlovsky, V. [DMCC-Engineering, Kiev (Ukraine). Inst. of Electrodynamics; Dolzhenitsa, Y. [DMCC Engineering, Kiev (Ukraine); Ushapovskiy, K. [National Power Co. Ukrenergo, Kiev (Ukraine)

    2009-07-01

    As a result of deregulation in the power industry, energy trade and markets are pushing transmission system operators to operate their systems closer to the edge of the power transfer capability. Voltage instability and inadequate reactive power support of generators is a key factor in most major outages around the world. The ideal way to control power systems is to avoid emergencies by reliable planning and secure operation of power systems. Therefore, the accurate calculation of the power transfer capability of transmission interfaces is an important task on the planning and operation stages. This paper discussed the issue of transfer capability assessment and monitoring for interfaces with static var compensator (SVC) and load shedding schemes. It also proposed a special measure, a distance to voltage instability point, to monitor transfer capability on-line. The distance may be observed by measurement of SVC output. The paper considered the problem of optimal SVC size selection and a new approach was proposed based on P-V curves analysis. The paper discussed the problem formulation and proposed approach. A case was also presented in order to demonstrate the proposed approach on the IPS Ukraine-Crimea interface. It was concluded that the proposed approach allows the optimal rating of SVC for increasing transfers capability of transmission corridors. 12 refs., 9 figs.

  1. Automated Transmission Loss Measurement in the Structural Acoustic Loads and Transmission Facility at NASA Langley Research Center

    Science.gov (United States)

    Klos, J.; Brown, S. A.

    2002-01-01

    A technique to measure the radiated acoustic intensity and transmission loss of panels is documented in this paper. This facility has been upgraded to include a test fixture that scans the acoustic intensity radiated from a panel on the anechoic receiving room side of the transmission loss window. The acoustic intensity incident on the panel from the reverberant side of the transmission loss window is estimated from measurements made using six stationary microphones in the reverberant source room. From the measured incident and radiated intensity, the sound power transmission loss is calculated. The setup of the facility and data acquisition system are documented. A transmission loss estimate of a typical panel is shown. The measurement-to-measurement and setup-to-setup repeatability of the transmission loss estimate are assessed. Conclusions are drawn about the ability to measure changes in transmission loss due to changes in panel construction.

  2. Atrial Fibrillation: Diagnosis

    Science.gov (United States)

    ... of this page please turn JavaScript on. Feature: Atrial Fibrillation Atrial Fibrillation: Diagnosis Past Issues / Winter 2015 Table of Contents ... of your body's cells and organs. Read More "Atrial Fibrillation" Articles Atrial Fibrillation / Who Is at Risk for ...

  3. Comparison of sound transmission in human ears and coupler loaded by audiometric earphones

    DEFF Research Database (Denmark)

    Ciric, Dejan; Hammershøi, Dorte

    2005-01-01

    earphones, which is related to coupling of these earphones to human ears and to the coupler. This is done by measurements of the transfer functions from input voltage of the earphone terminals to the entrance of the ear canal in two situations: open, and blocked. Similar measurements were carried out......The thresholds of hearing are usually determined using audiometric earphones. They are calibrated by means of a standardized acoustical coupler. In order to have determined thresholds independent of the earphone type, the coupler should approximate the average human ear closely. Nevertheless......, the differences among earphones as well as between human ears and the coupler affect the results of audiometric measurements inducing uncertainty. The influence of these differences is examined by investigating the sound transmission in both human ears and standardized coupler loaded by different audiometric...

  4. An improved DPSO with mutation based on similarity algorithm for optimization of transmission lines loading

    International Nuclear Information System (INIS)

    Shayeghi, H.; Mahdavi, M.; Bagheri, A.

    2010-01-01

    Static transmission network expansion planning (STNEP) problem acquires a principal role in power system planning and should be evaluated carefully. Up till now, various methods have been presented to solve the STNEP problem. But only in one of them, lines adequacy rate has been considered at the end of planning horizon and the problem has been optimized by discrete particle swarm optimization (DPSO). DPSO is a new population-based intelligence algorithm and exhibits good performance on solution of the large-scale, discrete and non-linear optimization problems like STNEP. However, during the running of the algorithm, the particles become more and more similar, and cluster into the best particle in the swarm, which make the swarm premature convergence around the local solution. In order to overcome these drawbacks and considering lines adequacy rate, in this paper, expansion planning has been implemented by merging lines loading parameter in the STNEP and inserting investment cost into the fitness function constraints using an improved DPSO algorithm. The proposed improved DPSO is a new conception, collectivity, which is based on similarity between the particle and the current global best particle in the swarm that can prevent the premature convergence of DPSO around the local solution. The proposed method has been tested on the Garver's network and a real transmission network in Iran, and compared with the DPSO based method for solution of the TNEP problem. The results show that the proposed improved DPSO based method by preventing the premature convergence is caused that with almost the same expansion costs, the network adequacy is increased considerably. Also, regarding the convergence curves of both methods, it can be seen that precision of the proposed algorithm for the solution of the STNEP problem is more than DPSO approach.

  5. A Flexible Load Control Strategy for Distribution Network to Reduce the Line Losses and to Eliminate the Transmission Congestion

    Directory of Open Access Journals (Sweden)

    Beibei Wang

    2017-01-01

    Full Text Available There are many uncertain factors in the modern distribution network, including the access of renewable energy sources and the heavy load level. The existence of these factors has brought challenges to the stability of the power distribution network, as well as increasing the risk of exceeding transmission capacity of distribution lines. The appearance of flexible load control technology provides a new idea to solve the above problems. Air conditioners (ACs account for a great proportion of all loads. In this paper, the model of dispatching AC loads in the regional power grid is constructed, and the direct load control (DLC method is adopted to reduce the load of ACs. An improved tabu search technique is proposed to solve the problem of network dispatch in distribution systems in order to reduce the resistive line losses and to eliminate the transmission congestion in lines under normal operating conditions. The optimal node solution is obtained to find the best location and reduction capacity of ACs for load control. To demonstrate the validity and effectiveness of the proposed method, a test system is studied. The numerical results are also given in this article, which reveal that the proposed method is promising.

  6. [Study on no-load running-in wear of power-shift steering transmission based on oil spectrum analysis].

    Science.gov (United States)

    Li, He-yan; Wang, Li-yong; Ma, Biao; Zheng, Chang-song; Chen, Man

    2009-04-01

    The running-in process wear rule of power-shift steering transmission can be studied conveniently and timely by using spectral analysis of oil. The configuration characteristic and the running-in mechanism of power-shift steering transmission were introduced firstly in the present paper. According to the discussion of running-in wear factors such as load, rotation speed, time, oil temperature, shifting number and original concentration of running-in oil, the wear calculation mode was established. The no-load running-in experiments of two power-shift steering transmissions were done, with different rotation speed and time. Based on the spectrum analysis of experiment result, the function relation between running-in wear and the oil original concentration and running-in speed was obtained, so the no-load running-in process wear calculation mode of power-shift steering transmission was confirmed. Through the experiment of other two power-shift steering transmissions, it was validated that the Cu element concentration can be calculated accurately by the wear calculation mode, which included the parameters such as oil original concentration, running-in speed, running-in time and gear shift alternate time. So the reference to evaluate the running-in quality and to constitute running-in regulations was gained.

  7. Atrial fibrillation

    African Journals Online (AJOL)

    ABEOLUGBENGAS

    optimal. Keywords: Atrial fibrillation, thrombosis, CHADS2 Score, stroke risk, hypertensive heart disease, ... (3,4). In developing countries, AF is a growing public health problem due to the epidemiologic transition from communicable to non- communicable diseases. However in ... ECG laboratory and was interpreted by two.

  8. Atrial fibrillation

    DEFF Research Database (Denmark)

    Olesen, Morten S; Nielsen, Morten W; Haunsø, Stig

    2014-01-01

    Atrial fibrillation (AF) is the most common cardiac arrhythmia affecting 1-2% of the general population. A number of studies have demonstrated that AF, and in particular lone AF, has a substantial genetic component. Monogenic mutations in lone and familial AF, although rare, have been recognized...

  9. Parametric Study of Tuned Mass Dampers for Long Span Transmission Tower-Line System under Wind Loads

    Directory of Open Access Journals (Sweden)

    Li Tian

    2016-01-01

    Full Text Available A parametric study of tuned mass dampers for a long span transmission tower-line system under wind loads is done in this paper. A three-dimensional finite element model of transmission tower-line system is established by SAP2000 software to numerically verify the effectiveness of the tuned mass damper device. The wind load time history is simulated based on Kaimal spectrum by the harmony superposition method. The equations of motion of a system with tuned mass damper under wind load excitation are proposed, and the schematic of tuned mass damper is introduced. The effects of mass ratio, frequency ratio, damping ratio, the change of the sag of transmission line, and the robustness of TMD are investigated, respectively. Results show that (1 the change of mass ratio has a greater effect on the vibration reduction ratio than those of frequency ratio and damping ratio, and the best vibration reduction ratio of TMD is not the frequency ratio of 1; (2 the sag-span ratio has an insignificant effect on the vibration reduction ratio of transmission tower when the change of sag-span ratio is not large; and (3 the effect of ice should be considered when the robustness study of TMD is carried out.

  10. Atrial Fibrillation: Treatment

    Science.gov (United States)

    ... of this page please turn JavaScript on. Feature: Atrial Fibrillation Atrial Fibrillation: Treatment Past Issues / Winter 2015 Table of Contents Treatment for atrial fibrillation depends on how often you have symptoms, how ...

  11. Atrial fibrillation

    OpenAIRE

    Munger, Thomas M.; Wu, Li-Qun; Shen, Win K.

    2013-01-01

    Atrial fibrillation is the most common arrhythmia affecting patients today. Disease prevalence is increasing at an alarming rate worldwide, and is associated with often catastrophic and costly consequences, including heart failure, syncope, dementia, and stroke. Therapies including anticoagulants, anti-arrhythmic medications, devices, and non-pharmacologic procedures in the last 30 years have improved patients' functionality with the disease. Nonetheless, it remains imperative that further re...

  12. Amyloid Fibril Solubility

    OpenAIRE

    Rizzi, L. G.; Auer, S.

    2015-01-01

    It is well established that amyloid fibril solubility is protein specific, but how solubility depends on the interactions between the fibril building blocks is not clear. Here we use a simple protein model and perform Monte Carlo simulations to directly measure the solubility of amyloid fibrils as a function of the interaction between the fibril building blocks. Our simulations confirms that the fibril solubility depends on the fibril thickness and that the relationship between the interactio...

  13. Effects of patient load and travel distance on HIV transmission in rural China: Implications for treatment as prevention.

    Directory of Open Access Journals (Sweden)

    M Kumi Smith

    Full Text Available Sustained viral suppression through ART reduces sexual HIV transmission risk, but may require routine access to reliable and effective medical care which may be difficult to obtain in resource constrained areas. We investigated the roles of patient load and travel distance to HIV care clinic on transmission risk in HIV serodiscordant couples in Henan Province, China.Cox proportional hazard models were used to compare HIV transmission events across couples living near, medium, or farther distances from their assigned HIV care clinics, as well as those attending clinics where clinicians bore high versus low patient loads.Most (84·4% of the 3695 serodiscordant couples lived within 10 kilometers of their assigned HIV clinic, and most (73·5% attended clinics with patient-to-provider ratios of at least 100:1. In adjusted Cox models, attending clinics where clinicians bore average patient loads of 100 or more elevated HIV transmission risk (aHR, 1·50, 95% CI, 1·00-4·84, an effect amplified in village tier clinics (aHR = 1·55; 95% CI, 1·23-6·78. Travel distance was associated with HIV transmission only after stratification; traveling medium distances to village clinics (5-10km increased transmission risk (aHR = 1·83, 95% CI, 1·04-3·21 whereas traveling longer distances to township or county level clinics lowered transmission risk (aHR = 0·10, 95% CI, 0·01-0·75.Higher patient loads at HIV clinics was associated with risk of HIV transmission in our population, particularly at village level clinics. Farther travel distance had divergent effects based on clinic tier, suggesting unique mechanisms operating across levels of resource availability. The resource intensity of long-term HIV treatment may place significant strains on small rural clinics, for which investments in additional support staff or time-saving tools such as point-of-care laboratory testing may bring about impactful change in treatment outcomes.

  14. A compact very wideband amplifying filter based on RTD loaded composite right/left-handed transmission lines.

    Science.gov (United States)

    Abu-Marasa, Mahmoud O Mahmoud; El-Khozondar, Hala Jarallah

    2015-01-01

    The composite right/left-handed (CRLH) transmission line (TL) is presented as a general TL possessing both left-handed (LH) and right-handed (RH) natures. RH materials have both positive permittivity and positive permeability, and LH materials have both negative permittivity and negative permeability. This paper aims to design and analyze nonlinear CRLH-TL transmission line loaded with resonant tunneling diode (RTD). The main application of this design is a very wideband and compact filter that amplifies the travelling signal. We used OrCAD and ADS software to analyze the proposed circuit. CRLH-TL consists of a microstrip line which is loaded with complementary split-rings resonators (CSRRs), series gaps, and shunt inductor connected parallel to the RTD. The designed structure possess a wide band that ranges from 5 to 10.5 GHz and amplifies signal up to 50 %. The proposed design is of interest to microwave compact component designers.

  15. Dynamic Reliability Analysis of Gear Transmission System of Wind Turbine in Consideration of Randomness of Loadings and Parameters

    Directory of Open Access Journals (Sweden)

    Lei Wang

    2014-01-01

    Full Text Available A dynamic model of gear transmission system of wind turbine is built with consideration of randomness of loads and parameters. The dynamic response of the system is obtained using the theory of random sampling and the Runge-Kutta method. According to rain flow counting principle, the dynamic meshing forces are converted into a series of luffing fatigue load spectra. The amplitude and frequency of the equivalent stress are obtained using equivalent method of Geber quadratic curve. Moreover, the dynamic reliability model of components and system is built according to the theory of probability of cumulative fatigue damage. The system reliability with the random variation of parameters is calculated and the influence of random parameters on dynamic reliability of components is analyzed. In the end, the results of the proposed method are compared with that of Monte Carlo method. This paper can be instrumental in the design of wind turbine gear transmission system with more advantageous dynamic reliability.

  16. Maternal plasma viral load and neutralizing/enhancing antibodies in vertical transmission of HIV: A non-randomized prospective study

    Directory of Open Access Journals (Sweden)

    Weiss Heidi

    2005-02-01

    Full Text Available Abstract Background We examined the association and interaction between maternal viral load and antibodies in vertical transmission of HIV in a non-randomized prospective study of 43 HIV-1 infected pregnant women who attended the San Juan City Hospital, Puerto Rico, and their 45 newborn infants. The women and infants received antiretroviral therapy. Methods A nested PCR assay of the HIV-1 envelope V3 region and infant PBMC culture were performed to determine HIV status of the infants. Maternal and infant plasma were tested for HIV neutralization or enhancement in monocyte-derived macrophages. Results Twelve (26.7% infants were positive by the HIV V3 PCR assay and 3 of the 12 were also positive by culture. There was a trend of agreement between high maternal viral load and HIV transmission by multivariate analysis (OR = 2.5, CI = 0.92, p = 0.0681. Both maternal and infant plasma significantly (p = 0.001 for both reduced HIV replication at 10-1 dilution compared with HIV negative plasma. Infant plasma neutralized HIV (p = 0.001 at 10-2 dilution but maternal plasma lost neutralizing effect at this dilution. At 10-3 dilution both maternal and infant plasma increased virus replication above that obtained with HIV negative plasma but only the increase by maternal plasma was statistically significant (p = 0.005. There were good agreements in enhancing activity in plasma between mother-infant pairs, but there was no significant association between HIV enhancement by maternal plasma and vertical transmission. Conclusion Although not statistically significant, the trend of association between maternal viral load and maternal-infant transmission of HIV supports the finding that viral load is a predictor of maternal-infant transmission. Both maternal and infant plasma neutralized HIV at low dilution and enhanced virus replication at high dilution. The antiretroviral treatments that the women received and the small sample size may have contributed to the

  17. The Reusable Load Cell with Protection Applied for Online Monitoring of Overhead Transmission Lines Based on Fiber Bragg Grating

    Directory of Open Access Journals (Sweden)

    Guoming Ma

    2016-06-01

    Full Text Available Heavy ice coating of high–voltage overhead transmission lines may lead to conductor breakage and tower collapse causing the unexpected interrupt of power supply. The optical load cell applied in ice monitoring systems is immune to electromagnetic interference and has no need of a power supply on site. Therefore, it has become a hot research topic in China and other countries. In this paper, to solve the problem of eccentric load in measurement, we adopt the shearing structure with additional grooves to improve the strain distribution and acquire good repeatability. Then, the fiber Bragg grating (FBG with a permanent weldable package are mounted onto the front/rear groove of the elastic element by spot welding, the direction deviation of FBGs is 90° from each other to achieve temperature compensation without an extra FBG. After that, protection parts are designed to guarantee high sensitivity for a light load condition and industrial safety under a heavy load up to 65 kN. The results of tension experiments indicate that the sensitivity and resolution of the load cell is 0.1285 pm/N and 7.782 N in the conventional measuring range (0–10 kN. Heavy load tension experiments prove that the protection structure works and the sensitivity and resolution are not changed after several high load (65 kN cycles. In addition, the experiment shows that the resolution of the sensor is 87.79 N in the large load range, allowing the parameter to be used in heavy icing monitoring.

  18. Deconstructing glucagon fibrillation

    DEFF Research Database (Denmark)

    Ghodke, Shirin

    Aggregation of misfolded proteins into ordered amyloid fibrils has deep implications in disease pathology as well as in pharmaceutical production of therapeutic proteins. This thesis elucidates the fibrillation pathway of the therapeutic peptide hormone, glucagon and explores the biophysical basis...... of its inherent fibril polymorphism by varying physicochemical factors like temperature, pressure and co-solvents. This work demonstrates the important role of hydration in the fibrillation process as well as in fibril polymorphism....

  19. Atrial Fibrillation

    DEFF Research Database (Denmark)

    Staerk, Laila; Sherer, Jason A; Ko, Darae

    2017-01-01

    that advanced age, male sex, and European ancestry are prominent AF risk factors. Other modifiable risk factors include sedentary lifestyle, smoking, obesity, diabetes mellitus, obstructive sleep apnea, and elevated blood pressure predispose to AF, and each factor has been shown to induce structural......The past 3 decades have been characterized by an exponential growth in knowledge and advances in the clinical treatment of atrial fibrillation (AF). It is now known that AF genesis requires a vulnerable atrial substrate and that the formation and composition of this substrate may vary depending...... and electric remodeling of the atria. Both heart failure and myocardial infarction increase risk of AF and vice versa creating a feed-forward loop that increases mortality. Other cardiovascular outcomes attributed to AF, including stroke and thromboembolism, are well established, and epidemiology studies have...

  20. Design and analysis of lumped resistor loaded metamaterial absorber with transmission band.

    Science.gov (United States)

    Chen, Xi; Li, Youquan; Fu, Yunqi; Yuan, Naichang

    2012-12-17

    A new type of multi-layer metamaterial (MM) absorber is represented in this paper, which behave as a dielectric slab in transmission band and act as an absorber in another lower band. The equivalent circuit model of each layer in this MM absorber has been established. The transmission line (TL) model is introduced to analysis the mechanism of electromagnetic wave traveling through this MM absorber. Both theoretical and experimental results indicate this MM absorber has a transmission band at 21GHz and an absorptive band from 5GHz to 13GHz. A good match of TL model results and measurement results verified the validity of TL model in analyzing and optimizing the performances of this kind of absorber.

  1. Investigation of bandwidth loading in optical fibre transmission using amplified spontaneous emission noise.

    Science.gov (United States)

    Elson, Daniel J; Saavedra, Gabriel; Shi, Kai; Semrau, Daniel; Galdino, Lidia; Killey, Robert; Thomsen, Benn C; Bayvel, Polina

    2017-08-07

    The use of spectrally shaped amplified spontaneous emission noise (SS-ASE) as a method for emulating interfering channels in optical fibre transmission systems has been studied. It is shown that the use of SS-ASE leads to a slightly pessimistic performance relative to the use of conventionally modulated interfering channels in the nonlinear regime. The additional nonlinear interference noise (on the channel under test), due to the Gaussian nature of SS-ASE, has been calculated using a combination of the Gaussian noise (GN) and enhanced GN (EGN) models for the entire C-band (4.5 THz) and experimentally shown to provide a lower bound for transmission performance.

  2. Flexible Transmission Network Expansion Planning Considering Uncertain Renewable Generation and Load Demand Based on Hybrid Clustering Analysis

    Directory of Open Access Journals (Sweden)

    Yun-Hao Li

    2015-12-01

    Full Text Available This paper presents a flexible transmission network expansion planning (TNEP approach considering uncertainty. A novel hybrid clustering technique, which integrates the graph partitioning method and rough fuzzy clustering, is proposed to cope with uncertain renewable generation and load demand. The proposed clustering method is capable of recognizing the actual cluster distribution of complex datasets and providing high-quality clustering results. By clustering the hourly data for renewable generation and load demand, a multi-scenario model is proposed to consider the corresponding uncertainties in TNEP. Furthermore, due to the peak distribution characteristics of renewable generation and heavy investment in transmission, the traditional TNEP, which caters to rated renewable power output, is usually uneconomic. To improve the economic efficiency, the multi-objective optimization is incorporated into the multi-scenario TNEP model, while the curtailment of renewable generation is considered as one of the optimization objectives. The solution framework applies a modified NSGA-II algorithm to obtain a set of Pareto optimal planning schemes with different levels of investment costs and renewable generation curtailments. Numerical results on the IEEE RTS-24 system demonstrated the robustness and effectiveness of the proposed approach.

  3. Critical System Cascading Collapse Assessment for Determining the Sensitive Transmission Lines and Severity of Total Loading Conditions

    Directory of Open Access Journals (Sweden)

    Nur Ashida Salim

    2013-01-01

    Full Text Available This paper presents a computationally accurate technique used to determine the estimated average probability of a system cascading collapse considering the effect of hidden failure on a protection system. This includes an accurate calculation of the probability of hidden failure as it will give significant effect on the results of the estimated average probability of system cascading collapse. The estimated average probability of a system cascading collapse is then used to determine the severe loading condition contributing to a higher risk of a system cascading collapse. This information is important because it will assist the utility to determine the maximum level of increase in the system loading condition before the occurrence of critical power system cascading collapse. Furthermore, the initial tripping of sensitive transmission line contributing to a critical system cascading collapse can also be determined by using the proposed method. Based on the results obtained from this study, it was found that selecting the accurate probability of hidden failure is very important as it will affect the estimated average probability of a system cascading collapse. Comparative study has been done with other techniques to verify the effectiveness of the proposed method used in the determination of sensitive transmission lines.

  4. Atrial fibrillation - discharge

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/patientinstructions/000237.htm Atrial fibrillation - discharge To use the sharing features on this ... have been in the hospital because you have atrial fibrillation . This condition occurs when your heart beats faster ...

  5. Atrial Fibrillation: Complications

    Science.gov (United States)

    ... of this page please turn JavaScript on. Feature: Atrial Fibrillation Atrial Fibrillation: Complications Past Issues / Winter 2015 Table of Contents ... has two major complications—stroke and heart failure. Atrial Fibrillation and Stroke Click to enlarge image This illustration ...

  6. Atrial Fibrillation Medications

    Science.gov (United States)

    ... Peripheral Artery Disease Venous Thromboembolism Aortic Aneurysm More Atrial Fibrillation Medications Updated:Jun 28,2017 Understand medications and ... you. This content was last reviewed July 2016. Atrial Fibrillation • Introduction • What is Atrial Fibrillation? • Why AFib Matters ...

  7. Atrial Fibrillation in Children

    Science.gov (United States)

    ... Peripheral Artery Disease Venous Thromboembolism Aortic Aneurysm More Atrial Fibrillation in Children Updated:Oct 18,2016 Does your ... arrhythmia. This content was last reviewed July 2016. Atrial Fibrillation • Introduction • What is Atrial Fibrillation? • Why AFib Matters ...

  8. Collagen fibrillogenesis in situ: fibril segments are intermediates in matrix assembly.

    OpenAIRE

    Birk, D E; Zycband, E I; Winkelmann, D A; Trelstad, R L

    1989-01-01

    The assembly of discontinuous fibril segments and bundles was studied in 14-day chicken embryo tendons by using serial sections, transmission electron microscopy, and computer-assisted image reconstruction. Fibril segments were first found in extracytoplasmic channels, the sites of their polymerization; they also were found within fibril bundles. Single fibril segments were followed over their entire length in consecutive sections, and their lengths ranged from 7 to 15 microns. Structural dif...

  9. Optimizing cellulose fibrillation for the production of cellulose nanofibrils by a disk grinder

    Science.gov (United States)

    Chuanshuang Hu; Yu Zhao; Kecheng Li; J.Y. Zhu; Roland Gleisner

    2015-01-01

    The fibrillation of a bleached kraft eucalyptus pulp was investigated by means of a laboratory-scale disk grinder for the production of cellulose nanofibrils (CNF), while the parameters disk rotating speed, solid loading, and fibrillation duration were varied. The cumulative energy consumption was monitored during fibrillation. The degree of polymerization (DP) and...

  10. Antenatal HIV-1 RNA load and timing of mother to child transmission; a nested case-control study in a resource poor setting

    Directory of Open Access Journals (Sweden)

    Chirenje Mike Z

    2010-08-01

    Full Text Available Abstract Objective To determine HIV-1 RNA load during the third trimester of pregnancy and evaluate its effect on in utero and intra-partum/postpartum transmissions in a breastfeeding population. Design A nested case-control study within a PMTCT cohort of antiretroviral therapy naive pregnant women and their infants. Methods A case was a mother who transmitted HIV-1 to her infant (transmitter who was matched to one HIV-1 positive but non-transmitting mother (control. Results From a cohort of 691 pregnant women, 177 (25.6% were HIV-1 positive at enrolment and from these 29 (23% transmitted HIV-1 to their infants, 10 and 19 during in utero and intra-partum/postpartum respectively. Twenty-four mothers sero-converted after delivery and three transmitted HIV-1 to their infants. Each unit increase in log10 viral load was associated with a 178 cells/mm3 and 0.2 g/dL decrease in TLC and hemoglobin levels, p = 0.048 and 0.021 respectively, and a 29% increase in the risk of transmission, p = 0.023. Intra-partum/postpartum transmitters had significantly higher mean viral load relative to their matched controls, p = 0.034. Conclusion Antenatal serum HIV-1 RNA load, TLC and hemoglobin levels were significantly associated with vertical transmission but this association was independent of transmission time. This finding supports the rationale for preventive strategies designed to reduce vertical transmission by lowering maternal viral load.

  11. Atrial fibrillation.

    Science.gov (United States)

    Bang, Casper N

    2013-10-01

    Atrial fibrillation (AF) is a common complication after myocardial infarction (MI) and new-onset AF has been demonstrated to be associated with adverse outcome and a large excess risk of death in both MI and aortic stenosis (AS) patients. Prevention of new-onset AF is therefore a potential therapeutic target in AS and MI patients. Lipid-lowering drugs, particularly statins, have anti-inflammatory and antioxidant properties that may prevent AF. Accordingly, statins are recommended as a class IIa recommendation for prevention of new-onset AF after coronary artery bypass grafting (CABG). However, this preventive effect has not been investigated on new-onset AF in asymptomatic patients with AS or a large scale first-time MI patient sample and data in patients not undergoing invasive cardiac interventions are limited. This PhD thesis was conducted at the Heart Centre, Rigshospitalet, Denmark, with the aim to investigate the three aforementioned questions and to add to the existing evidence of AF prevention with statins. This was done using three different settings: 1) a randomized patients sample of 1,873 from the Simvastatin and Ezetimibe in Aortic Stenosis (SEAS) study, 2) a register patient sample of 97,499 with first-time MI, and 3) all published studies until beginning of June 2011 examining statin treatment on new-onset and recurrent AF in patients not undergoing cardiac surgery. This thesis revealed that statins did not lower the incidence or the time to new-onset AF in patients with asymptomatic AS. However, statin treatment showed an independently preventive effect on new-onset AF, including type-dependent effect and a trend to dosage-dependent effect. In addition, this thesis showed that good compliance to statin treatment was important to prevent new-onset AF. Finally, the meta-analysis in this PhD thesis showed a preventive effect in the observational studies although this effect was absent in the randomized controlled trials. Based on this PhD thesis

  12. Destroying activity of magnetoferritin on lysozyme amyloid fibrils

    Energy Technology Data Exchange (ETDEWEB)

    Kopcansky, Peter; Siposova, Katarina [Institute of Experimental Physics, SAS, Watsonova 47, 040 01 Kosice (Slovakia); Melnikova, Lucia, E-mail: melnikova@saske.sk [Institute of Experimental Physics, SAS, Watsonova 47, 040 01 Kosice (Slovakia); Bednarikova, Zuzana [Institute of Experimental Physics, SAS, Watsonova 47, 040 01 Kosice (Slovakia); Institute of Chemical Sciences, Faculty of Sciences, Safarik University, Kosice (Slovakia); Timko, Milan; Mitroova, Zuzana; Antosova, Andrea [Institute of Experimental Physics, SAS, Watsonova 47, 040 01 Kosice (Slovakia); Garamus, Vasil M. [Helmholtz-Zentrum Geesthacht: Centre for Materials and Coastal Research, Max-Planck-Street 1, 21502 Geesthacht (Germany); Petrenko, Viktor I. [Joint Institute for Nuclear Research, Joliot-Curie 6, Dubna, 141980 Moscow Region (Russian Federation); Kyiv Taras Shevchenko National University, Volodymyrska Street 64, Kyiv 01033 (Ukraine); Avdeev, Mikhail V. [Joint Institute for Nuclear Research, Joliot-Curie 6, Dubna, 141980 Moscow Region (Russian Federation); Gazova, Zuzana [Institute of Experimental Physics, SAS, Watsonova 47, 040 01 Kosice (Slovakia); Department of Medical and Clinical Biochemistry and LABMED, Tr. SNP 1, 040 11 Kosice (Slovakia)

    2015-03-01

    Presence of protein amyloid aggregates (oligomers, protofilaments, fibrils) is associated with many diseases as diabetes mellitus or Alzheimer's disease. The interaction between lysozyme amyloid fibrils and magnetoferritin loaded with different amount of iron atoms (168 or 532 atoms) has been investigated by small-angle X-rays scattering and thioflavin T fluorescence measurements. Results suggest that magnetoferritin caused an iron atom-concentration dependent reduction of lysozyme fibril size. - Highlights: • The interaction between lysozyme amyloid fibrils and magnetoferritin loaded with different amount of iron atoms (168 or 532 atoms) has been investigated by small-angle X-rays scattering and thioflavin T fluorescence measurements. • Results suggest that magnetoferritin caused an iron atom-concentration dependent reduction of lysozyme fibril size.

  13. Polarized light transmission in ferrofluids loaded with carbon nanotubes in the presence of a uniform magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Vales-Pinzón, C., E-mail: cvales@mda.cinvestav.mx [Applied Physics Department, CINVESTAV-Unidad Mérida, Antigua carretera a Progreso km 6, A.P. 73, Cordemex, Mérida Yucatán 97310 (Mexico); Alvarado-Gil, J.J. [Applied Physics Department, CINVESTAV-Unidad Mérida, Antigua carretera a Progreso km 6, A.P. 73, Cordemex, Mérida Yucatán 97310 (Mexico); Medina-Esquivel, R. [Facultad de Ingeniería-UADY, Av. Industrias no Contaminantes por Periférico Norte, A.P. 150, Cordemex, Mérida, Yucatán (Mexico); Martínez-Torres, P. [Department of Mechanical Engineering, University of California, Riverside, 900 University Ave., Riverside, CA 92521 (United States)

    2014-11-15

    Magneto-optic phenomena in ferrofluids have been shown to be related to the formation of chain structures, due to the arrangement of the ferromagnetic particles, induced by an applied magnetic field. In this work, the effects on transmission of polarized light due to anisotropic effects induced by an external magnetic field in ferrofluids with carbon nanotubes are studied. The time response of the system presents two well defined stages, in the first one, which is very short, the fluid behaves as a polarizer. In contrast in the second stage, the effects of light transmission dominate. In this stage the transmitted light intensity grows with time and after a long time reaches a constant stable value. It is shown that these phenomena depend on the carbon nanotubes concentration as well as on the strength of the applied magnetic field. Using a simple model that considers a chain-like structure formation, it is possible to determine the rate of agglomeration of the formed structures and the attenuation coefficient of the transmitted light. The formation of nanostructures leads to variation in the transmitted light, depending on the polarization of the incident light. These magnetic nanostructures can find numerous applications in nanotechnology, optical devices and medicine. - Highlights: • Carbon nanotubes in ferrofluids favor the formation of chain-like structures. • In the presence of a magnetic field ferrofluids loaded with CNT behaves as a polarizer. • Transmitted light increases when samples are under a magnetic field then stabilizes. • Attenuation time for transmitted light and agglomeration parameters were studied.

  14. Vulnerability to ventricular fibrillation

    Science.gov (United States)

    Janse, Michiel J.

    1998-03-01

    One of the factors that favors the development of ventricular fibrillation is an increase in the dispersion of refractoriness. Experiments will be described in which an increase in dispersion in the recovery of excitability was determined during brief episodes of enhanced sympathetic nerve activity, known to increase the risk of fibrillation. Whereas in the normal heart ventricular fibrillation can be induced by a strong electrical shock, a premature stimulus of moderate intensity only induces fibrillation in the presence of regional ischemia, which greatly increases the dispersion of refractoriness. One factor that is of importance for the transition of reentrant ventricular tachycardia to ventricular fibrillation during acute regional ischemia is the subendocardial Purkinje system. After selective destruction of the Purkinje network by lugol, reentrant tachycardias still develop in the ischemic region, but they do not degenerate into fibrillation. Finally, attempts were made to determine the minimal mass of thin ventricular myocardium required to sustain fibrillation induced by burst pacing. This was done by freezing of subendocardial and midmural layers. The rim of surviving epicardial muscle had to be larger than 20 g. Extracellular electrograms during fibrillation in both the intact and the "frozen" left ventricle were indistinguishable, but activation patterns were markedly different. In the intact ventricle epicardial activation was compatible with multiple wavelet reentry, in the "frozen" heart a single, or at most two wandering reentrant waves were seen.

  15. Research on the impact of surface properties of particle on damping effect in gear transmission under high speed and heavy load

    Science.gov (United States)

    Xiao, Wangqiang; Chen, Zhiwei; Pan, Tianlong; Li, Jiani

    2018-01-01

    The vibration and noise from gear transmission have great damage on the mechanical equipment and operators. Through inelastic collisions and friction between particles, the energy can be dissipated in gear transmission. A dynamic model of particle dampers in gear transmission was put forward in this paper. The performance of particle dampers in centrifugal fields under different rotational speeds and load was investigated. The surface properties such as the impact of coefficient of restitution and friction coefficient of the particle on the damping effect were analyzed and the total energy loss was obtained by discrete element method (DEM). The vibration from time-varying mesh stiffness was effectively reduced by particle dampers and the optimum coefficient of restitution was discovered under different rotational speeds and load. Then, a test bench for gear transmission was constructed, and the vibration of driven gear and driving gear were measured through a three-directional wireless acceleration sensor. The research results agree well with the simulation results. While at relatively high speed, smaller coefficient of restitution achieves better damping effect. As to friction coefficient, at relatively high speed, the energy dissipation climbs up and then declines with the increase of the friction coefficient. The results can provide guidelines for the application of particle damper in gear transmission.

  16. Phytol-loaded PLGA nanoparticle as a modulator of Alzheimer's toxic Aβ peptide aggregation and fibrillation associated with impaired neuronal cell function.

    Science.gov (United States)

    Sathya, Sethuraman; Shanmuganathan, Balakrishnan; Saranya, Shanmugasundram; Vaidevi, Sethuraman; Ruckmani, Kandasamy; Pandima Devi, Kasi

    2017-10-25

    Alzheimer's disease (AD) is an unfavourable neurological condition of the brain leading to the loss of behavioural and cognitive skills of the aging population. At present, drugs representing cholinesterase inhibitors provide lateral side effects to AD patients. Hence, there is a need for improved fabrication of drugs without side effects, for which nanoencapsulated bioactive compounds that can cross the blood-brain barrier offer new hope as novel alternative treatment strategy for AD. This study involved synthesis of phytol loaded poly(lactic-co-glycolic acid) (PLGA) nanoparticles by solvent evaporation method. Physico-chemical characterization of phytol-PLGA NPs through the field emission scanning electron microscope, dynamic laser scattering (DLS) measurement revealed that the particles were nanosize range with smooth surface and spherical morphology. Furthermore, the biocompatibility of drug/polymer ratio was investigated by power X-ray diffraction (PXRD) and Fourier-transform infrared spectroscopic (FT-IR) analysis. The in vitro drug release study showed that the phytol was released in a sustained manner. Moreover, phytol-PLGA NPs were able to disrupt amyloid aggregates, exhibit anti-cholinesterase and anti-oxidative property and are non-cytotoxic in Neuro2a cells.

  17. Effect of particle size, filler loadings and x-ray tube voltage on the transmitted x-ray transmission in tungsten oxide-epoxy composites.

    Science.gov (United States)

    Noor Azman, N Z; Siddiqui, S A; Hart, R; Low, I M

    2013-01-01

    The effect of particle size, filler loadings and x-ray tube voltage on the x-ray transmission in WO(3)-epoxy composites has been investigated using the mammography unit and a general radiography unit. Results indicate that nano-sized WO(3) has a better ability to attenuate the x-ray beam generated by lower tube voltages (25-35 kV) when compared to micro-sized WO(3) of the same filler loading. However, the effect of particle size on x-ray transmission was negligible at the higher x-ray tube voltages (40-120 kV). Crown Copyright © 2012. Published by Elsevier Ltd. All rights reserved.

  18. What Is Atrial Fibrillation?

    Science.gov (United States)

    ANSWERS by heart Cardiovascular Conditions What Is Atrial Fibrillation? Your heart has a natural pacemaker, called the “sinus node,” that makes electrical signals. These signals cause the heart to contract and pump ...

  19. Should we build wind farms close to load or invest in transmission to access better wind resources in remote areas? A case study in the MISO region

    International Nuclear Information System (INIS)

    Lamy, Julian V.; Jaramillo, Paulina; Azevedo, Inês L.; Wiser, Ryan

    2016-01-01

    Wind speeds in remote areas are sometimes very high, but transmission costs to access these locations can be prohibitive. We present a conceptual model to estimate the economics of accessing high quality wind resources in remote areas to comply with renewable energy policy targets, and apply the model to the Midwestern grid (MISO) as a case study. We assess the goal of providing 40 TWh of new wind generation while minimizing costs, and include temporal aspects of wind power (variability costs and correlation to market prices) as well as total wind power produced from different farms. We find that building wind farms in North/South Dakota (windiest states) compared to Illinois (less windy, but close to load) would only be economical if the incremental transmission costs to access them were below $360/kW of wind capacity (break-even value). Historically, the incremental transmission costs for wind development in North/South Dakota compared to in Illinois are about twice this value. However, the break-even incremental transmission cost for wind farms in Minnesota/Iowa (also windy states) is $250/kW, which is consistent with historical costs. We conclude that wind development in Minnesota/Iowa is likely more economical to meet MISO renewable targets compared to North/South Dakota or Illinois. - Highlights: •We evaluate the economics of building wind farms in remote areas in MISO. •We present a conceptual wind site selection model to meet 40 TWh of new wind. •We use the model to compare remote windy sites to less windy ones closer to load. •We show break-even transmission costs that would justify remote wind development. •Comparing break-even values to historical costs, MN/IA sites are most economical.

  20. Visualisation of collagen fibrils in joint cartilage using STIM

    International Nuclear Information System (INIS)

    Reinert, T.; Reibetanz, U.; Vogt, J.; Butz, T.; Werner, A.; Gruender, W.

    2001-01-01

    The scanning transmission ion microscopy (STIM) method was used to investigate the collagen network structure of the articular cartilage from a pig's knee in comparison with high resolution nuclear magnetic resonance imaging (microscopic NMR-tomography) and polarised light microscopy (PLM). Single collagen fibrils down to 200 nm in diameter were visualised. It was proved that the cartilage collagen network consists partly of zones of oriented fibrils as suggested by NMR measurements. Radially oriented fibrils were found in the zone near the calcified zone (hypertrophic zone) of both tibia and femur, and in the tibial radial zone. Tangentially oriented fibrils were found in the femoral and tibial superficial zone and in a second zone of the femoral cartilage. Polarisation light microscopy reveals broader zones of orientation than it was found with STIM

  1. [Signaling indicator of ventricular fibrillation].

    Science.gov (United States)

    Agizim, G M; Pasichnik, T V; Sherman, A M

    1976-01-01

    The purpose of the work was to design an appliance for reliable detection of ventricular fibrillation. Frequency-amplitude spectrum of electrocardiograms taken in dogs with normal rhythm and fibrillation, as well as the impulse ratio in normalcy, tachycardia and in fibrillation were investigated. An appliance for automatic separation of ventricular fibrillation by referring to pulse ratio is described. The designed device is shown to have a high degree of discrimination and noise-immunity.

  2. Atrial Fibrillation (AF or AFib)

    Science.gov (United States)

    ... Peripheral Artery Disease Venous Thromboembolism Aortic Aneurysm More Atrial Fibrillation (AF or AFib) Updated:Aug 14,2017 What ... to the Terms and Conditions and Privacy Policy Atrial Fibrillation • Introduction • What is Atrial Fibrillation? • Why AFib Matters ...

  3. Atrial Fibrillation and Hyperthyroidism

    Directory of Open Access Journals (Sweden)

    Jayaprasad N

    2005-10-01

    Full Text Available Atrial fibrillation occurs in 10 – 15% of patients with hyperthyroidism. Low serum thyrotropin concentration is an independent risk factor for atrial fibrillation. Thyroid hormone contributes to arrythmogenic activity by altering the electrophysiological characteristics of atrial myocytes by shortening the action potential duration, enhancing automaticity and triggered activity in the pulmonary vein cardio myocytes. Hyperthyroidism results in excess mortality from increased incidence of circulatory diseases and dysrhythmias. Incidence of cerebral embolism is more in hyperthyroid patients with atrial fibrillation, especially in the elderly and anti-coagulation is indicated in them. Treatment of hyperthyroidism results in conversion to sinus rhythm in up to two-third of patients. Beta-blockers reduce left ventricular hypertrophy and atrial and ventricular arrhythmias in patients with hyperthyroidism. Treatment of sub clinical hyperthyroidism is controversial. Optimizing dose of thyroxine treatment in those with replacement therapy and beta-blockers is useful in exogenous subclinical hyperthyroidism.

  4. Modulation of atrial fibrillation

    NARCIS (Netherlands)

    Geuzebroek, G.S.C.

    2013-01-01

    In this thesis we investigate the results of various surgical procedures for atrial fibrillation which have been performed in the last 2 decades in the Sint Antonius Hospital, Nieuwegein, The Netherlands. In the 1990s the classical Maze III procedure was the main surgical technique for

  5. Rivaroxaban in atrial fibrillation

    Directory of Open Access Journals (Sweden)

    Giorgi MA

    2012-08-01

    Full Text Available Mariano A Giorgi,1,2 Lucas San Miguel31Cardiology Service, Centro de Educación Médica e Investigaciones Clínicas “Norberto Quirno”, 2Department of Pharmacology, School of Medicine, Universidad Austral, 3Department of Cardiology and Cardiovascular Surgery, FLENI, Buenos Aires, ArgentinaAbstract: Warfarin is the traditional therapeutic option available to manage thromboembolic risk in atrial fibrillation. The hemorrhagic risk with warfarin depends mainly on the international normalized ratio (INR. Data from randomized controlled trials show that patients have a therapeutic INR (2.00–3.00 only 61%–68% of the time while taking warfarin, and this target is sometimes hard to establish. Many compounds have been developed in order to optimize the profile of oral anticoagulants. We focus on one of them, rivaroxaban, comparing it with novel alternatives, ie, dabigatran and apixaban. The indication for rivaroxaban in nonvalvular atrial fibrillation was evaluated in ROCKET-AF (Rivaroxaban-once daily, Oral, direct factor Xa inhibition Compared with vitamin K antagonism for prevention of stroke and Embolism Trial in Atrial Fibrillation. In this trial, rivaroxaban was associated with a 12% reduction in the incidence of the primary endpoint compared with warfarin (hazard ratio 0.88; 95% confidence interval [CI] 0.74–1.03; P < 0.001 for noninferiority and P = 0.12 for superiority. However, patients remained in the therapeutic range for INR only 55% of the time, which is less than that in RE-LY (the Randomized Evaluation of Long-Term Anticoagulation Therapy, 64% and in the ARISTOTLE trial (Apixaban for Reduction in Stroke and Other Thromboembolic Events in Atrial Fibrillation, 66%. This shorter time spent in the therapeutic range has been one of the main criticisms of the ROCKET-AF trial, but could actually reflect what happens in real life. In addition, rivaroxaban exhibits good pharmacokinetic and pharmacoeconomic properties. Novel anticoagulants

  6. Asymptotic behavior and numerical simulations for an infection load-structured epidemiological model; Application to the transmission of prion pathologies

    OpenAIRE

    Perasso, Antoine; Razafison, Ulrich

    2014-01-01

    In this article is studied an infection load-structured SI model with exponential growth of the infection, that incorporates a potential external source of contamination. We perform the analysis of the time asymptotic behavior of the solution by exhibiting epidemiological thresholds, such as the basic reproduction number, that ensure extinction or persistence of the disease in the contagion process. Moreover, a numerical scheme adapted to the model is developped and analyzed. This scheme is t...

  7. HYPERTHYROIDISM AND ATRIAL FIBRILLATION

    Directory of Open Access Journals (Sweden)

    I. M. Marusenko

    2017-01-01

    Full Text Available Review on a problem of the development of atrial fibrillation in patients with thyrotoxicosis is presented. Thyrotoxicosis is one of the most frequent endocrine diseases, conceding only to a diabetes mellitus. The most frequent reasons of hyperthyroidism are Graves’ disease and functional thyroid autonomy. The authors give an analysis of data on the cardiac effects of thyrotoxicosis, features of heart remodeling under the influence of thyroid hyperfunction, prevalence of atrial fibrillation in thyrotoxicosis, depending on age, as well as the possibility of restoring sinus rhythm in the combination of these diseases. Particular attention is paid to the effect on the heart of subclinical thyrotoxicosis, which is defined as a dysfunction of the thyroid gland, characterized by low serum concentration of thyrotropin, normal values of free thyroxine and free triiodothyronine. Subclinical hyperthyroidism is also capable of causing heart remodeling and diastolic dysfunction.Prevalence of thyrotoxicosis in elderly people is higher in areas of iodine deficiency; it is relevant for our country due to the large territory of iodine deficiency. In elderly patients, the cardiac effects of thyrotoxicosis prevail in the clinical picture, that makes it difficult to diagnose endocrine disorders, and correction of thyrotoxicosis is critically important for the successful control of the heart rhythm. The article also discusses the problem of thyrotoxic cardiomyopathy, caused by the toxic effect of excess thyroid hormones: features of this heart disorder, factors affecting its formation, clinical significance and contribution to the development of rhythm disturbances. The greatest significance is the development of atrial fibrillation as a result of thyrotox-icosis in older patients who already have various cardiovascular diseases.Atrial fibrillation is the most frequent heart rhythm disorder in thyrotoxicosis. The main cause of arrhythmia in hyperthyroidism is the

  8. Atrial fibrillation and female sex.

    Science.gov (United States)

    Anselmino, Matteo; Battaglia, Alberto; Gallo, Cristina; Gili, Sebastiano; Matta, Mario; Castagno, Davide; Ferraris, Federico; Giustetto, Carla; Gaita, Fiorenzo

    2015-12-01

    Atrial fibrillation is the most common supraventricular arrhythmia. Its prevalence increases with age and preferentially affects male patients. Over 75 years of age, however, female patients being more prevalent, the absolute number of patients affected is similar between sexes. Despite this, few data are available in the literature concerning sex-related differences in atrial fibrillation patients. The present systematic review therefore considers comorbidities, referring symptoms, quality of life, pharmacological approaches and trans-catheter ablation in female rather than in male atrial fibrillation patients in search of parameters that may have an impact on the treatment outcome. In brief, female atrial fibrillation patients more commonly present comorbidities, leading to a higher prevalence of persistent atrial fibrillation; moreover, they refer to hospital care later and with a longer disease history. Atrial fibrillation symptoms relate to low quality of life in female patients; in fact, atrial fibrillation paroxysm usually presents higher heart rate, leading to preferentially adopt a rate rather than a rhythm-control strategy. Female atrial fibrillation patients present an increased risk of stroke, worsened by the lower oral anticoagulant prescription rate related to the concomitant higher haemorrhagic risk profile. Trans-catheter ablation is under-used in female patients and, on the contrary, they are more commonly affected by anti-arrhythmic drug side effects.

  9. SOUND TRANSMISSION LOSS OF A DOUBLE-LEAF SOLID-MICROPERFORATED PARTITION UNDER NORMAL INCIDENCE OF ACOUSTIC LOADING

    Directory of Open Access Journals (Sweden)

    Ahmad Yusuf Ismail

    2011-12-01

    Full Text Available 0 0 1 332 1894 International Islamic University 15 4 2222 14.0 Normal 0 false false false EN-US JA X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Times New Roman";} The micro-perforated panel (MPP is recently well-known as an alternative ‘green‘ sound absorber replacing the conventional porous materials. Constructed from a solid panel which provides a non-abrassive structure and also an optically attractive surface, there gives a feasibility to implement such a panel inside a vehicle cabin. This paper is the preliminary study to investigate the sound transmission loss (TL of a solid panel coupled with a micro-perforated panel to form a doube-leaf partition which is already known as a lightweigth stucture for noise insulation in vehicles and buildings. The mathematical model for the TL subjected to normal incidence of acoustic excitation is derived. The results show that its performance substantially improves at the troublesome frequency of mass-air-mass resonance which occurs in the conventional double-leaf solid partition. This is important particularly for the noise source predominant at low frequencies. This can also be controlled by tuning the hole size and number as well as the air gap between the panels.  ABSTRAK: Panel bertebuk mikro (micro-perforated panel (MPP kebelakangan ini dikenali sebagai alternatif penyerap bunyi yang mesra alam menggantikan bahan berliang lazim. Dibina daripada satu panel padu yang memberikan satu struktur tak lelas dan juga satu permukaan yang menarik, ia memberikan kemungkinan penggunaan panel tersebut di dalam kabin kenderaan. Tesis ini merupakan kajian permulaan dalam mengkaji hilang pancaran bunyi

  10. S14G-humanin inhibits Aβ1-42 fibril formation, disaggregates preformed fibrils, and protects against Aβ-induced cytotoxicity in vitro.

    Science.gov (United States)

    Zhang, Wei; Du, Ying; Bai, Miao; Xi, Ye; Li, Zhuyi; Miao, Jianting

    2013-03-01

    The aggregation of soluble amyloid-beta (Aβ) peptide into oligomers/fibrils is one of the key pathological features in Alzheimer's disease (AD). The Aβ aggregates are considered to play a pivotal role in the pathogenesis of AD. Therefore, inhibiting Aβ aggregation and destabilizing preformed Aβ fibrils would be an attractive therapeutic target for prevention and treatment of AD. S14G-humanin (HNG), a synthetic derivative of Humanin (HN), has been shown to be a strong neuroprotective agent against various AD-related insults. Recent studies have shown that HNG can significantly improve cognitive deficits and reduce insoluble Aβ levels as well as amyloid plaque burden without affecting amyloid precursor protein processing and Aβ production in transgenic AD models. However, the potential mechanisms by which HNG reduces Aβ-related pathology in vivo remain obscure. In the present study, we found that HNG could significantly inhibit monomeric Aβ1-42 aggregation into fibrils and destabilize preformed Aβ1-42 fibrils in a concentration-dependent manner by Thioflavin T fluorescence assay. In transmission electron microscope study, we observed that HNG was effective in inhibiting Aβ1-42 fibril formation and disrupting preformed Aβ1-42 fibrils, exhibiting various types of amorphous aggregates without identifiable Aβ fibrils. Furthermore, HNG-treated monomeric or fibrillar Aβ1-42 was found to significantly reduce Aβ1-42-mediated cytotoxic effects on PC12 cells in a dose-dependent manner by MTT assay. Collectively, our results demonstrate for the first time that HNG not only inhibits Aβ1-42 fibril formation but also disaggregates preformed Aβ1-42 fibrils, which provides the novel evidence that HNG may have anti-Aβ aggregation and fibrillogenesis, and fibril-destabilizing properties. Together with previous studies, we concluded that HNG may have promising therapeutic potential as a multitarget agent for the prevention and/or treatment of AD. Copyright © 2013

  11. Dementia and Atrial Fibrillation

    DEFF Research Database (Denmark)

    Pastori, Daniele; Miyazawa, Kazuo; Lip, Gregory Y H

    2018-01-01

    The risk of developing dementia is increased in patients with atrial fibrillation (AF), with the incidence of both conditions increasing with aging. Patients with dementia frequently do not receiving adequate thrombo-prophylaxis, because of the inability to monitor INR and/or to achieve...... in therapeutic range during VKAs therapy, the assessment of cognitive impairment may help identify those patients who may benefit from switching to NOACs. In conclusion, patients with AF and dementia benefit from anticoagulation and should not be denied receiving adequate stroke prevention. Cognitive function...

  12. An in vitro screening assay based on synthetic prion protein peptides for identification of fibril-interfering compounds

    NARCIS (Netherlands)

    Boshuizen, R.S.; Langeveld, J.P.M.; Salmona, M.; Williams, A.; Meloen, R.H.; Langendijk, J.P.

    2004-01-01

    Transmissible spongiform encephalopathies are neurodegenerative diseases and are considered to be caused by malformed prion proteins accumulated into fibrillar structures that can then aggregate to form larger deposits or amyloid plaques. The identification of fibril-interfering compounds is of

  13. Biomimetic mineralization of collagen fibrils induced by amine-terminated PAMAM dendrimers--PAMAM dendrimers for remineralization.

    Science.gov (United States)

    Liang, Kunneng; Gao, Yuan; Li, Jianshu; Liao, Ying; Xiao, Shimeng; Zhou, Xuedong; Li, Jiyao

    2015-01-01

    Achieving biomimetic mineralization of collagen fibrils by mimicking the role of non-collagenous proteins (NCPs) with biomimetic analogs is of great interest in the fields of material science and stomatology. Amine-terminated PAMAM dendrimer (PAMAM-NH2), which possesses a highly ordered architecture and many calcium coordination sites, may be a desirable template for simulating NCPs to induce mineralization of collagen fibrils. In this study, we focused on the ability of PAMAM-NH2 to mineralize collagen fibrils. Type-I collagen fibrils were reconstituted over 400-mesh formvar-and-carbon-coated gold grids and treated with a third-generation PAMAM-NH2 (G3-PAMAM-NH2) solution. The treated collagen fibrils were immersed in artificial saliva for different lengths of time. The morphologies of the mineralized reconstituted type-I collagen fibrils were characterized by transmission electron microscopy. No obvious mineralized collagen fibrils were detected in the control group. On the contrary, collagen fibrils were heavily mineralized in the experimental group. Most importantly, intrafibrillar mineralization was achieved within the reconstituted type-I collagen fibrils. In this study, we successfully induced biomimetic mineralization within type-I collagen fibrils using G3-PAMAM-NH2. This strategy may serve as a potential therapeutic technique for restoring completely demineralized collagenous mineralized tissues.

  14. Measurement of the Mechanical Properties of Intact Collagen Fibrils

    Science.gov (United States)

    Mercedes, H.; Heim, A.; Matthews, W. G.; Koob, T.

    2006-03-01

    Motivated by the genetic disorder Ehlers-Danlos syndrome (EDS), in which proper collagen synthesis is interrupted, we are investigating the structural and mechanical properties of collagen fibrils. The fibrous glycoprotein collagen is the most abundant protein found in the human body and plays a key role in the extracellular matrix of the connective tissue, the properties of which are altered in EDS. We have selected as our model system the collagen fibrils of the sea cucumber dermis, a naturally mutable tissue. This system allows us to work with native fibrils which have their proteoglycan complement intact, something that is not possible with reconstituted mammalian collagen fibrils. Using atomic force microscopy, we measure, as a function of the concentration of divalent cations, the fibril diameter, its response to force loading, and the changes in its rigidity. Through these experiments, we will shed light on the mechanisms which control the properties of the sea cucumber dermis and hope to help explain the altered connective tissue extracellular matrix properties associated with EDS.

  15. Structure-based design of non-natural amino-acid inhibitors of amyloid fibril formation

    Energy Technology Data Exchange (ETDEWEB)

    Sievers, Stuart A.; Karanicolas, John; Chang, Howard W.; Zhao, Anni; Jiang, Lin; Zirafi, Onofrio; Stevens, Jason T.; Münch, Jan; Baker, David; Eisenberg, David (UCLA); (UWASH); (UL); (Kansas); (Ulm)

    2011-09-20

    Many globular and natively disordered proteins can convert into amyloid fibrils. These fibrils are associated with numerous pathologies as well as with normal cellular functions, and frequently form during protein denaturation. Inhibitors of pathological amyloid fibril formation could be useful in the development of therapeutics, provided that the inhibitors were specific enough to avoid interfering with normal processes. Here we show that computer-aided, structure-based design can yield highly specific peptide inhibitors of amyloid formation. Using known atomic structures of segments of amyloid fibrils as templates, we have designed and characterized an all-D-amino-acid inhibitor of the fibril formation of the tau protein associated with Alzheimer's disease, and a non-natural L-amino-acid inhibitor of an amyloid fibril that enhances sexual transmission of human immunodeficiency virus. Our results indicate that peptides from structure-based designs can disrupt the fibril formation of full-length proteins, including those, such as tau protein, that lack fully ordered native structures. Because the inhibiting peptides have been designed on structures of dual-{beta}-sheet 'steric zippers', the successful inhibition of amyloid fibril formation strengthens the hypothesis that amyloid spines contain steric zippers.

  16. The Surprising Role of Amyloid Fibrils in HIV Infection

    Directory of Open Access Journals (Sweden)

    James Shorter

    2012-05-01

    Full Text Available Despite its discovery over 30 years ago, human immunodeficiency virus (HIV continues to threaten public health worldwide. Semen is the principal vehicle for the transmission of this retrovirus and several endogenous peptides in semen, including fragments of prostatic acid phosphatase (PAP248-286 and PAP85-120 and semenogelins (SEM1 and SEM2, assemble into amyloid fibrils that promote HIV infection. For example, PAP248-286 fibrils, termed SEVI (Semen derived Enhancer of Viral Infection, potentiate HIV infection by up to 105-fold. Fibrils enhance infectivity by facilitating virion attachment and fusion to target cells, whereas soluble peptides have no effect. Importantly, the stimulatory effect is greatest at low viral titers, which mimics mucosal transmission of HIV, where relatively few virions traverse the mucosal barrier. Devising a method to rapidly reverse fibril formation (rather than simply inhibit it would provide an innovative and urgently needed preventative strategy for reducing HIV infection via the sexual route. Targeting a host-encoded protein conformer represents a departure from traditional microbicidal approaches that target the viral machinery, and could synergize with direct antiviral approaches. Here, we review the identification of these amyloidogenic peptides, their mechanism of action, and various strategies for inhibiting their HIV-enhancing effects.

  17. Tendon Force Transmission at the Nanoscale

    DEFF Research Database (Denmark)

    Svensson, René

    2013-01-01

    of connective tissue function that are poorly understood. One such aspect is the microscopic mechanisms of force transmission through tendons over macroscopic distances. Force transmission is at the heart of tendon function, but the large range of scales in the hierarchical structure of tendons has made...... it difficult to tackle. The tendon hierarchy ranges from molecules (2 nm) over fibrils (200 nm), fibers (2 μm) and fascicles (200 μm) to tendons (10 mm), and to derive the mechanisms of force transmission it is necessary to know the mechanical behavior at each hierarchical level. The aim of the present work...... was to elucidate the mechanisms of force transmission in tendons primarily by investigating the mechanical behavior at the hierarchical level of collagen fibrils. To do so we have developed an atomic force microscopy (AFM) method for tensile testing of native collagen fibrils. The thesis contains five papers...

  18. Quantifying Transmission.

    Science.gov (United States)

    Woolhouse, Mark

    2017-07-01

    Transmissibility is the defining characteristic of infectious diseases. Quantifying transmission matters for understanding infectious disease epidemiology and designing evidence-based disease control programs. Tracing individual transmission events can be achieved by epidemiological investigation coupled with pathogen typing or genome sequencing. Individual infectiousness can be estimated by measuring pathogen loads, but few studies have directly estimated the ability of infected hosts to transmit to uninfected hosts. Individuals' opportunities to transmit infection are dependent on behavioral and other risk factors relevant given the transmission route of the pathogen concerned. Transmission at the population level can be quantified through knowledge of risk factors in the population or phylogeographic analysis of pathogen sequence data. Mathematical model-based approaches require estimation of the per capita transmission rate and basic reproduction number, obtained by fitting models to case data and/or analysis of pathogen sequence data. Heterogeneities in infectiousness, contact behavior, and susceptibility can have substantial effects on the epidemiology of an infectious disease, so estimates of only mean values may be insufficient. For some pathogens, super-shedders (infected individuals who are highly infectious) and super-spreaders (individuals with more opportunities to transmit infection) may be important. Future work on quantifying transmission should involve integrated analyses of multiple data sources.

  19. Meta-analysis to estimate the load of Leptospira excreted in urine: beyond rats as important sources of transmission in low-income rural communities.

    Science.gov (United States)

    Barragan, Veronica; Nieto, Nathan; Keim, Paul; Pearson, Talima

    2017-01-28

    Leptospirosis is a major zoonotic disease with widespread distribution and a large impact on human health. Carrier animals excrete pathogenic Leptospira primarily in their urine. Infection occurs when the pathogen enters a host through mucosa or small skin abrasions. Humans and other animals are exposed to the pathogen by direct contact with urine, contaminated soil or water. While many factors influence environmental cycling and the transmission of Leptospira to humans, the load of pathogenic Leptospira in the environment is likely to play a major role. Peridomestic rats are often implicated as a potential source of human disease; however exposure to other animals is a risk factor as well. The aim of this report is to highlight the importance of various carrier animals in terms of the quantity of Leptospira shed into the environment. For this, we performed a systematic literature review and a meta-analysis of the amount of pathogen that various animal species shed in their urine. The quantity of pathogen has been reported for cows, deer, dogs, humans, mice, and rats, in a total of 14 research articles. We estimated the average Leptospira per unit volume shed by each animal species, and the daily environmental contribution by considering the total volume of urine excreted by each carrier animal. Rats excrete the highest quantity of Leptospira per millilitre of urine (median = 5.7 × 10 6  cells), but large mammals excrete much more urine and thus shed significantly more Leptospira per day (5.1 × 10 8 to 1.3 × 10 9  cells). Here we illustrate how, in a low-income rural Ecuadorian community, host population demographics, and prevalence of Leptospira infection can be integrated with estimates of shed Leptospira to suggest that peridomestic cattle may be more important than rats in environmental cycling and ultimately, transmission to humans.

  20. Efficacy and safety of telbivudine in preventing mother-to-infant transmission of HBV in pregnant women with high HBV DNA load

    Directory of Open Access Journals (Sweden)

    SUN Weihui

    2013-08-01

    Full Text Available ObjectiveTo evaluate the efficacy and safety of telbivudine given from the 12th week of gestation in preventing mother-to-infant transmission of hepatitis B virus (HBV in pregnant women with high HBV DNA load. MethodsEighty pregnant women (at 12 weeks of gestation with chronic hepatitis B, who had a HBV DNA load higher than 1.0×107 copies/ml, were enrolled. The patients were divided into two groups according to their personal preferences: treatment group (n=38 and control group (n=42. The treatment group received oral telbivudine (600 mg once daily until 12 weeks after delivery and was administered compound glycyrrhizin for liver protection, while the control group was given compound glycyrrhizin for liver protection alone. All infants in both groups were vaccinated with hepatitis B immunoglobulin (200 IU and HBV vaccine (20 μg after birth. The mother-to-infant transmission of HBV was indicated by the presence of HBsAg and HBV DNA in infants at 7 months after birth. The HBV DNA levels in these women were measured, and the positive rate of HBsAg in infants was determined. The difference in positive rate of HBsAg was analyzed by chi-square test; the between-group comparison was analyzed by group t(t′-test, and the before-after comparison was analyzed by paired t-test. ResultsThe treatment group showed significantly decreased HBV DNA and alanine aminotransferase levels before delivery. The HBV DNA load of treatment group dropped rapidly after 2 weeks of treatment and then decreased slowly until delivery. The treatment group had significantly decreased HBV DNA levels beforedelivery and at 12 weeks after delivery (t=29.15, P<0.01; t=40.06, P<0.01, but the control group showed no significant changes (P>0.05. The treatment group had significantly lower HBV DNA levels than the control group before delivery and at 12 weeks after delivery (P<0.01. No infants in the treatment group were HBV-positive, versus a positive rate of 14.3% in the

  1. Agent-based modeling traction force mediated compaction of cell-populated collagen gels using physically realistic fibril mechanics.

    Science.gov (United States)

    Reinhardt, James W; Gooch, Keith J

    2014-02-01

    Agent-based modeling was used to model collagen fibrils, composed of a string of nodes serially connected by links that act as Hookean springs. Bending mechanics are implemented as torsional springs that act upon each set of three serially connected nodes as a linear function of angular deflection about the central node. These fibrils were evaluated under conditions that simulated axial extension, simple three-point bending and an end-loaded cantilever. The deformation of fibrils under axial loading varied <0.001% from the analytical solution for linearly elastic fibrils. For fibrils between 100 μm and 200 μm in length experiencing small deflections, differences between simulated deflections and their analytical solutions were <1% for fibrils experiencing three-point bending and <7% for fibrils experiencing cantilever bending. When these new rules for fibril mechanics were introduced into a model that allowed for cross-linking of fibrils to form a network and the application of cell traction force, the fibrous network underwent macroscopic compaction and aligned between cells. Further, fibril density increased between cells to a greater extent than that observed macroscopically and appeared similar to matrical tracks that have been observed experimentally in cell-populated collagen gels. This behavior is consistent with observations in previous versions of the model that did not allow for the physically realistic simulation of fibril mechanics. The significance of the torsional spring constant value was then explored to determine its impact on remodeling of the simulated fibrous network. Although a stronger torsional spring constant reduced the degree of quantitative remodeling that occurred, the inclusion of torsional springs in the model was not necessary for the model to reproduce key qualitative aspects of remodeling, indicating that the presence of Hookean springs is essential for this behavior. These results suggest that traction force mediated matrix

  2. Pharmacological Treatment for Atrial Fibrillation

    Directory of Open Access Journals (Sweden)

    Kaoru Sugi, MD PhD

    2005-01-01

    Full Text Available Pharmacological treatment for atrial fibrillation has a variety of purposes, such as pharmacological defibrillation, maintenance of sinus rhythm, heart rate control to prevent congestive heart failure and prevention of both cerebral infarction and atrial remodeling. Sodium channel blockers are superior to potassium channel blockers for atrial defibrillation, while both sodium and potassium channel blockers are effective in the maintenance of sinus rhythm. In general, digitalis or Ca antagonists are used to control heart rate during atrial fibrillation to prevent congestive heart failure, while amiodarone or bepridil also reduce heart rates during atrial fibrillation. Anticoagulant therapy with warfarin is recommended to prevent cerebral infarction and angiotensin converting enzyme antagonists or angiotensin II receptor blockers are also used to prevent atrial remodeling. One should select appropriate drugs for treatment of atrial fibrillation according to the patient's condition.

  3. The effect of limited proteolysis by different proteases on the formation of whey protein fibrils.

    Science.gov (United States)

    Gao, Yu-Zhe; Xu, Hong-Hua; Ju, Ting-Ting; Zhao, Xin-Huai

    2013-01-01

    Four proteases: trypsin, protease A, pepsin, and protease M were selected to modify whey protein concentrate (WPC) at a low degree of hydrolysis (0.1, 0.2, and 0.3%) before adjusting to pH 2.0 and heating at 90°C to gain insight into the influence of proteolysis on fibril formation. The kinetics of fibril formation were performed on native and modified WPC using the fluorescent dye thioflavin T in conjunction with transmission electron microscopy and far-UV circular dichroism spectroscopy for the morphological and secondary structural analyses. The change in surface hydrophobicity and content of free sulfhydryl groups were also observed during the formation of fibrils for the native and modified WPC. The content of aggregation and thioflavin T kinetic data indicated that the ability of fibril formation was apparently different for WPC modified by the 4 proteases. Whey protein concentrate modified by trypsin aggregated more during heating and the fibril formation rate was faster than that of the native WPC. Whey protein concentrate modified by the other proteases showed slower aggregation with worse amyloid fibril morphology. Compared with the native WPC, the structure of WPC changed differently after being modified by proteases. The state of α-helix structure for modified WPC played the most important role in the formation of fibrils. Under the mild conditions used in this work, the α-helix structure of WPC modified by trypsin caused little destruction and resulted in fibrils with good morphology; the content of α-helices for WPC modified by other proteases decreased to 36.19 to 50.94%; thus, fibril formation was inhibited. In addition, it was beneficial for the modified WPC to form fibrils such that the surface hydrophobicity increased and the content of free sulfhydryl groups slightly decreased during heating. Copyright © 2013 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  4. Atrial fibrillation and heart failure: is atrial fibrillation a disease?

    Science.gov (United States)

    Tilman, V

    2014-09-01

    Atrial fibrillation in heart failure often occur together. The relationship between atrial fibrillation and heart failure has remained a subject of research. The main manifestation of the violation of hydrodynamics in heart failure is the increased end-diastolic pressure, which is transmitted through the intercommunicated system (left ventricle-left atrium-pulmonary veins-alveolar capillaries) causing increased pulmonary wedge pressure with the danger for pulmonary edema. End-diastolic pressure is the sum of left ventricle diastolic pressure and left atrial systolic pressure. Stopping the mechanical systole of the left atrium can reduce the pressure in the system in heart failure. Atrial fibrillation stops the mechanical systole of the left atrium and decreases the intercommunicating pressure and pulmonary wedge pressure. It is possible that atrial fibrillation is a mechanism for protection from increasing end-diastolic pressure and pulmonary wedge pressure, and prevents the danger of pulmonary edema. This hypothesis may explain the relationship between heart failure and atrial fibrillation and their frequent association. Copyright © 2014 Elsevier Ltd. All rights reserved.

  5. Generation-dependent effect of PAMAM dendrimers on human insulin fibrillation and thermal stability.

    Science.gov (United States)

    Nowacka, Olga; Milowska, Katarzyna; Belica-Pacha, Sylwia; Palecz, Bartlomiej; Šipošová, Katarina; Gazova, Zuzana; Bryszewska, Maria

    2016-01-01

    We have studied the effect of polyamidoamine (PAMAM) dendrimers of various generations on the thermal stability and fibrillation of human insulin. Thermostability of human insulin used differential scanning calorimetry (DSC), which showed two phase-transitions for insulin at 60 and 82°C. After adding dendrimers at 0.6 μmol/l, the first peaks disappeared and the second peaks were higher. We posited that, in the presence of dendrimers, the dimers in the solution were transformed into hexamers. The effect of dendrimers on insulin fibrillation was monitored by measuring ThT fluorescence, and visualization of insulin fibrils by transmission electron microscopy (TEM) and atomic force microscopy (AFM). The effect of PAMAM dendrimers on insulin fibrillation was strongly dependent on the dendrimers generation and dendrimer:protein ratio. Copyright © 2015 Elsevier B.V. All rights reserved.

  6. Viscoelastic behavior of discrete human collagen fibrils

    DEFF Research Database (Denmark)

    Svensson, Rene; Hassenkam, Tue; P, Hansen

    2010-01-01

    Whole tendon and fibril bundles display viscoelastic behavior, but to the best of our knowledge this property has not been directly measured in single human tendon fibrils. In the present work an atomic force microscopy (AFM) approach was used for tensile testing of two human patellar tendon...... fibrils. Fibrils were obtained from intact human fascicles, without any pre-treatment besides frozen storage. In the dry state a single isolated fibril was anchored to a substrate using epoxy glue, and the end of the fibril was glued on to an AFM cantilever for tensile testing. In phosphate buffered...... on the strain. The slope of the viscous response showed a strain rate dependence corresponding to a power function of powers 0.242 and 0.168 for the two patellar tendon fibrils, respectively. In conclusion, the present work provides direct evidence of viscoelastic behavior at the single fibril level, which has...

  7. Atrial fibrillation in KCNE1-null mice

    NARCIS (Netherlands)

    Temple, Joel; Frias, Patricio; Rottman, Jeffrey; Yang, Tao; Wu, Yuejin; Verheijck, E. Etienne; Zhang, Wei; Siprachanh, Chanthaphaychith; Kanki, Hideaki; Atkinson, James B.; King, Paul; Anderson, Mark E.; Kupershmidt, Sabina; Roden, Dan M.

    2005-01-01

    Although atrial fibrillation is the most common serious cardiac arrhythmia, the fundamental molecular pathways remain undefined. Mutations in KCNQ1, one component of a sympathetically activated cardiac potassium channel complex, cause familial atrial fibrillation, although the mechanisms in vivo are

  8. Why Atrial Fibrillation (AF or AFib) Matters

    Science.gov (United States)

    ... Artery Disease Venous Thromboembolism Aortic Aneurysm More Why Atrial Fibrillation (AF or AFib) Matters Updated:Aug 22,2017 ... possible. This content was last reviewed July 2016. Atrial Fibrillation • Introduction • What is Atrial Fibrillation? • Why AFib Matters ...

  9. Energetics Underlying Twist Polymorphisms in Amyloid Fibrils

    NARCIS (Netherlands)

    Periole, Xavier; Huber, Thomas; Bonito-Oliva, Alessandra; Aberg, Karina C; van der Wel, Patrick C A; Sakmar, Thomas P; Marrink, Siewert J

    2018-01-01

    Amyloid fibrils are highly ordered protein aggregates associated with more than 40 human diseases. The exact conditions in which the fibrils are grown determine many types of reported fibril polymorphism, including different twist patterns. Twist-based polymorphs display unique mechanical properties

  10. Epigallocatechin-3-gallate rapidly remodels PAP85-120, SEM1(45-107, and SEM2(49-107 seminal amyloid fibrils

    Directory of Open Access Journals (Sweden)

    Laura M. Castellano

    2015-09-01

    Full Text Available Semen harbors amyloid fibrils formed by proteolytic fragments of prostatic acid phosphatase (PAP248-286 and PAP85-120 and semenogelins (SEM1 and SEM2 that potently enhance HIV infectivity. Amyloid but not soluble forms of these peptides enhance HIV infection. Thus, agents that remodel these amyloid fibrils could prevent HIV transmission. Here, we confirm that the green tea polyphenol, epigallocatechin-3-gallate (EGCG, slowly remodels fibrils formed by PAP248-286 termed SEVI (semen derived enhancer of viral infection and also exerts a direct anti-viral effect. We elucidate for the first time that EGCG remodels PAP85-120, SEM1(45-107, and SEM2(49-107 fibrils more rapidly than SEVI fibrils. We establish EGCG as the first small molecule that can remodel all four classes of seminal amyloid. The combined anti-amyloid and anti-viral properties of EGCG could have utility in preventing HIV transmission.

  11. Nanomechanical properties of single amyloid fibrils

    International Nuclear Information System (INIS)

    Sweers, K K M; Bennink, M L; Subramaniam, V

    2012-01-01

    Amyloid fibrils are traditionally associated with neurodegenerative diseases like Alzheimer’s disease, Parkinson’s disease or Creutzfeldt-Jakob disease. However, the ability to form amyloid fibrils appears to be a more generic property of proteins. While disease-related, or pathological, amyloid fibrils are relevant for understanding the pathology and course of the disease, functional amyloids are involved, for example, in the exceptionally strong adhesive properties of natural adhesives. Amyloid fibrils are thus becoming increasingly interesting as versatile nanobiomaterials for applications in biotechnology. In the last decade a number of studies have reported on the intriguing mechanical characteristics of amyloid fibrils. In most of these studies atomic force microscopy (AFM) and atomic force spectroscopy play a central role. AFM techniques make it possible to probe, at nanometer length scales, and with exquisite control over the applied forces, biological samples in different environmental conditions. In this review we describe the different AFM techniques used for probing mechanical properties of single amyloid fibrils on the nanoscale. An overview is given of the existing mechanical studies on amyloid. We discuss the difficulties encountered with respect to the small fibril sizes and polymorphic behavior of amyloid fibrils. In particular, the different conformational packing of monomers within the fibrils leads to a heterogeneity in mechanical properties. We conclude with a brief outlook on how our knowledge of these mechanical properties of the amyloid fibrils can be exploited in the construction of nanomaterials from amyloid fibrils. (topical review)

  12. How does domain replacement affect fibril formation of the rabbit/human prion proteins.

    Directory of Open Access Journals (Sweden)

    Xu Yan

    Full Text Available It is known that in vivo human prion protein (PrP have the tendency to form fibril deposits and are associated with infectious fatal prion diseases, while the rabbit PrP does not readily form fibrils and is unlikely to cause prion diseases. Although we have previously demonstrated that amyloid fibrils formed by the rabbit PrP and the human PrP have different secondary structures and macromolecular crowding has different effects on fibril formation of the rabbit/human PrPs, we do not know which domains of PrPs cause such differences. In this study, we have constructed two PrP chimeras, rabbit chimera and human chimera, and investigated how domain replacement affects fibril formation of the rabbit/human PrPs.As revealed by thioflavin T binding assays and Sarkosyl-soluble SDS-PAGE, the presence of a strong crowding agent dramatically promotes fibril formation of both chimeras. As evidenced by circular dichroism, Fourier transform infrared spectroscopy, and proteinase K digestion assays, amyloid fibrils formed by human chimera have secondary structures and proteinase K-resistant features similar to those formed by the human PrP. However, amyloid fibrils formed by rabbit chimera have proteinase K-resistant features and secondary structures in crowded physiological environments different from those formed by the rabbit PrP, and secondary structures in dilute solutions similar to the rabbit PrP. The results from transmission electron microscopy show that macromolecular crowding caused human chimera but not rabbit chimera to form short fibrils and non-fibrillar particles.We demonstrate for the first time that the domains beyond PrP-H2H3 (β-strand 1, α-helix 1, and β-strand 2 have a remarkable effect on fibrillization of the rabbit PrP but almost no effect on the human PrP. Our findings can help to explain why amyloid fibrils formed by the rabbit PrP and the human PrP have different secondary structures and why macromolecular crowding has different

  13. Genetic basis of atrial fibrillation

    Directory of Open Access Journals (Sweden)

    Oscar Campuzano

    2016-12-01

    Full Text Available Atrial fibrillation is the most common sustained arrhythmia and remains as one of main challenges in current clinical practice. The disease may be induced secondary to other diseases such as hypertension, valvular heart disease, and heart failure, conferring an increased risk of stroke and sudden death. Epidemiological studies have provided evidence that genetic factors play an important role and up to 30% of clinically diagnosed patients may have a family history of atrial fibrillation. To date, several rare variants have been identified in a wide range of genes associated with ionic channels, calcium handling protein, fibrosis, conduction and inflammation. Important advances in clinical, genetic and molecular basis have been performed over the last decade, improving diagnosis and treatment. However, the genetics of atrial fibrillation is complex and pathophysiological data remains still unraveling. A better understanding of the genetic basis will induce accurate risk stratification and personalized clinical treatment. In this review, we have focused on current genetics basis of atrial fibrillation.

  14. Stroke Prevention in Atrial Fibrillation

    Science.gov (United States)

    ... Atrial Fibrillation Christian T. Ruff Download PDF https://doi.org/10.1161/CIRCULATIONAHA.111.067843 Circulation. 2012; 125: ... e588-e590 , originally published April 23, 2012 https://doi.org/10.1161/CIRCULATIONAHA.111.067843 Citation Manager Formats ...

  15. Surgical Treatment of Atrial Fibrillation

    Directory of Open Access Journals (Sweden)

    Naghmeh Moshtaghi

    2008-12-01

    Full Text Available Atrial fibrillation is the most prevalent permanent arrhythmia. It may be associated with other cardiac pathologies which need surgical treatment. Various types of surgery including the traditional cut-sew operations and operations using different energy sources are currently in use. In comparison with medical treatment, surgery is safe, effective, and has reliable results.

  16. Personalized management of atrial fibrillation

    DEFF Research Database (Denmark)

    Kirchhof, Paulus; Breithardt, Günter; Aliot, Etienne

    2013-01-01

    The management of atrial fibrillation (AF) has seen marked changes in past years, with the introduction of new oral anticoagulants, new antiarrhythmic drugs, and the emergence of catheter ablation as a common intervention for rhythm control. Furthermore, new technologies enhance our ability to de...

  17. Small passenger car transmission test: Mercury Lynx ATX transmission

    Science.gov (United States)

    Bujold, M. P.

    1981-01-01

    The testing of a Mercury Lynx automatic transmission is reported. The transmission was tested in accordance with a passenger car automatic transmission test code (SAE J65lb) which required drive performance, coast performance, and no load test conditions. Under these conditions, the transmission attained maximum efficiencies in the mid-ninety percent range both for drive performance test and coast performance tests. The torque, speed, and efficiency curves are presented, which provide the complete performance characteristics for the Mercury Lynx automatic transmission.

  18. Nanoscale characterization of isolated individual type I collagen fibrils: polarization and piezoelectricity.

    Science.gov (United States)

    Minary-Jolandan, Majid; Yu, Min-Feng

    2009-02-25

    Piezoresponse force microscopy was applied to directly study individual type I collagen fibrils with diameters of approximately 100 nm isolated from bovine Achilles tendon. It was revealed that single collagen fibrils behave predominantly as shear piezoelectric materials with a piezoelectric coefficient on the order of 1 pm V(-1), and have unipolar axial polarization throughout their entire length. It was estimated that, under reasonable shear load conditions, the fibrils were capable of generating an electric potential up to tens of millivolts. The result substantiates the nanoscale origin of piezoelectricity in bone and tendons, and implies also the potential importance of the shear load-transfer mechanism, which has been the principle basis of the nanoscale mechanics model of collagen, in mechanoelectric transduction in bone.

  19. Chondroitin Sulfate Perlecan Enhances Collagen Fibril Formation

    DEFF Research Database (Denmark)

    Kvist, A. J.; Johnson, A. E.; Mörgelin, M.

    2006-01-01

    in collagen type II fibril assembly by perlecan-null chondrocytes. Cartilage perlecan is a heparin sulfate or a mixed heparan sulfate/chondroitin sulfate proteoglycan. The latter form binds collagen and accelerates fibril formation in vitro, with more defined fibril morphology and increased fibril diameters...... produced in the presence of perlecan. Interestingly, the enhancement of collagen fibril formation is independent on the core protein and is mimicked by chondroitin sulfate E but neither by chondroitin sulfate D nor dextran sulfate. Furthermore, perlecan chondroitin sulfate contains the 4,6-disulfated...... disaccharides typical for chondroitin sulfate E. Indeed, purified glycosaminoglycans from perlecan-enriched fractions of cartilage extracts contain elevated levels of 4,6-disulfated chondroitin sulfate disaccharides and enhance collagen fibril formation. The effect on collagen assembly is proportional...

  20. Risk of atrial fibrillation in diabetes mellitus

    DEFF Research Database (Denmark)

    Pallisgaard, Jannik L; Schjerning, Anne-Marie; Lindhardt, Tommi B

    2016-01-01

    AIM: Diabetes has been associated with atrial fibrillation but the current evidence is conflicting. In particular knowledge regarding young diabetes patients and the risk of developing atrial fibrillation is sparse. The aim of our study was to investigate the risk of atrial fibrillation in patients...... with diabetes compared to the background population in Denmark. METHODS AND RESULTS: Through Danish nationwide registries we included persons above 18 years of age and without prior atrial fibrillation and/or diabetes from 1996 to 2012. The study cohort was divided into a background population without diabetes...... and a diabetes group. The absolute risk of developing atrial fibrillation was calculated and Poisson regression models adjusted for sex, age and comorbidities were used to calculate incidence rate ratios of atrial fibrillation. The total study cohort included 5,081,087 persons, 4,827,713 (95%) in the background...

  1. [Panic disorder and atrial fibrillation].

    Science.gov (United States)

    Olazabal Eizaguirre, N; Chavez, R; González-Torres, M A; Gaviria, M

    2013-10-01

    This paper studies the relationship between atrial fibrillation and panic disorder. There are often doubts on the differential diagnosis in emergency services and general medical settings. Panic disorder prevalence rates have been found to be high in patients suffering from atrial fibrillation. Various studies have observed that patients diagnosed with anxiety disorders frequently have higher cardiovascular disease rates compared to the general population. Usually, patients suffering from panic disorder exhibit somatic complaints suggesting coronary disease, such as chest pain or palpitations. The aim is to make the correct diagnosis and treatment for these different illnesses, and to decrease the costs due to misdiagnosis. Copyright © 2012 Sociedad Española de Médicos de Atención Primaria (SEMERGEN). Publicado por Elsevier España. All rights reserved.

  2. Micromechanical bending of single collagen fibrils using atomic force microscopy

    NARCIS (Netherlands)

    Yang, Lanti; van der Werf, Kees O; Koopman, Bart F J M; Subramaniam, Vinod; Bennink, Martin L; Dijkstra, Pieter J; Feijen, Jan

    A new micromechanical technique was developed to study the mechanical properties of single collagen fibrils. Single collagen fibrils, the basic components of the collagen fiber, have a characteristic highly organized structure. Fibrils were isolated from collagenous materials and their mechanical

  3. Remote Monitoring for Chronic Disease Management: Atrial Fibrillation and Heart Failure.

    Science.gov (United States)

    Ono, Maki; Varma, Niraj

    2018-03-01

    This review aims to cover the latest evidence of remote monitoring of cardiac implantable electronic devices for the management of atrial fibrillation and heart failure. Remote monitoring is useful for early detection for device-detected atrial fibrillation, which increases the risk of thromboembolic events. Early anticoagulation based on remote monitoring potentially reduces the risk of stroke, but optimal alert setting needs to be clarified. Multiparameter monitoring with automatic transmission is useful for heart failure management. Improved adherence to remote monitoring and an optimal algorithm for transmitted alerts and their management are warranted in the management of heart failure. Copyright © 2017 Elsevier Inc. All rights reserved.

  4. Microcapsules with protein fibril reinforced shells: effect of fibril properties on mechanical strength of the shell.

    Science.gov (United States)

    Humblet-Hua, Nam-Phuong K; van der Linden, Erik; Sagis, Leonard M C

    2012-09-19

    In this study, we produced microcapsules using layer-by-layer adsorption of food-grade polyelectrolytes on an emulsion droplet template. We compared the mechanical stability of microcapsules to shells consisting of alternating layers of ovalbumin-high methoxyl pectin (Ova-HMP) complexes and semi-flexible ovalbumin (Ova) fibrils (average contour length, L(c) ~ 200 nm), with microcapsules built of alternating layers of lysozyme-high methoxyl pectin (LYS-HMP) complexes and lysozyme (LYS) fibrils. Two types of LYS fibrils were used: short and rod-like (L(c) ~ 500 nm) and long and semi-flexible (L(c) = 1.2-1.5 μm). At a low number of layers (≤4), microcapsules from Ova complexes and fibrils were stronger than microcapsules prepared from LYS complexes and fibrils. With an increase of the number of layers, the mechanical stability of microcapsules from LYS-HMP/LYS fibrils increased significantly and capsules were stronger than those prepared from Ova-HMP/Ova fibrils with the same number of layers. The contour length of the LYS fibrils did not have a significant effect on mechanical stability of the LYS-HMP/LYS fibril capsules. The stiffer LYS fibrils produce capsules with a hard but more brittle shell, whereas the semi-flexible Ova fibrils produce capsules with a softer but more stretchable shell. These results show that mechanical properties of this type of capsule can be tuned by varying the flexibility of the protein fibrils.

  5. The role of protonation in protein fibrillation

    DEFF Research Database (Denmark)

    Jeppesen, Martin D; Westh, Peter; Otzen, Daniel E

    2010-01-01

    Many proteins fibrillate at low pH despite a high population of charged side chains. Therefore exchange of protons between the fibrillating peptide and its surroundings may play an important role in fibrillation. Here, we use isothermal titration calorimetry to measure exchange of protons between...... buffer and the peptide hormone glucagon during fibrillation. Glucagon absorbs or releases protons to an extent which allows it to attain a net charge of zero in the fibrillar state, both at acidic and basic pH. Similar results are obtained for lysozyme. This suggests that side chain pKa values change...

  6. Dynamics of Fibril Growth and Feedback Motifs

    DEFF Research Database (Denmark)

    Cordsen, Pia

    in the literature were found, such as length distribution and apparant persistence lengths. It is found that at all concentrations, fibril growth is characterized by Poissonian stop-go dynamics where the fibril either grows (``go'') or does not grow (``stop''). A monomer-trimer model is proposed in which monomers...... chemical reaction rates of the model, and the theoretical and experimental growth probabilities are found to be in good agreement. Speed distributions of fibrils are also analysed and found to be in good agreement with the predictions of the model. Fibrils of the protein alpha-synuclein which are involved...

  7. Viscoelastic behavior of discrete human collagen fibrils

    DEFF Research Database (Denmark)

    Svensson, René; Hassenkam, Tue; Hansen, Philip

    2010-01-01

    Whole tendon and fibril bundles display viscoelastic behavior, but to the best of our knowledge this property has not been directly measured in single human tendon fibrils. In the present work an atomic force microscopy (AFM) approach was used for tensile testing of two human patellar tendon...... on the strain. The slope of the viscous response showed a strain rate dependence corresponding to a power function of powers 0.242 and 0.168 for the two patellar tendon fibrils, respectively. In conclusion, the present work provides direct evidence of viscoelastic behavior at the single fibril level, which has...

  8. Dimethyl Sulfoxide Induced Destabilization and Disassembly of Various Structural Variants of Insulin Fibrils Monitored by Vibrational Circular Dichroism.

    Science.gov (United States)

    Zhang, Ge; Babenko, Viktoria; Dzwolak, Wojciech; Keiderling, Timothy A

    2015-12-15

    Dimethyl sulfoxide (DMSO) induced destabilization of insulin fibrils has been previously studied by Fourier transform infrared spectroscopy and interpreted in terms of secondary structural changes. The variation of this process for fibrils with different types of higher-order morphological structures remained unclear. Here, we utilize vibrational circular dichroism (VCD), which has been reported to provide a useful biophysical probe of the supramolecular chirality of amyloid fibrils, to characterize changes in the macroscopic chirality following DMSO-induced disassembly for two types of insulin fibrils formed under different conditions, at different reduced pH values with and without added salt and agitation. We confirm that very high concentrations of DMSO can disaggregate both types of insulin fibrils, which initially maintained a β-sheet conformation and eventually changed their secondary structure to a disordered form. The two types responded to varying concentrations of DMSO, and disaggregation followed different mechanisms. Interconversion of specific insulin fibril morphological types also occurred during the destabilization process as monitored by VCD. With transmission electron microscopy, we were able to correlate the changes in VCD sign patterns to alteration of morphology of the insulin fibrils.

  9. Data for ion and seed dependent fibril assembly of a spidroin core domain

    Directory of Open Access Journals (Sweden)

    Martin Humenik

    2015-09-01

    Full Text Available This data article includes size exclusion chromatography data of soluble eADF4(C16, an engineered spider silk variant based on the core domain sequence of the natural dragline silk protein ADF4 of Araneus diadematus, in combination with light scattering; the protein is monomeric before assembly. The assembled mature fibrils were visualized by transmission electron microscopy (TEM and atomic force microscopy (AFM. Sonicated fibrils were used as seeds to by-pass the nucleation lag phase in eADF4(C16 assembly. We also provide data on the sedimentation kinetics of spider silk in the presence of different NaCl concentrations revealing very slow protein aggregation in comparison to the fast assembly triggered by phosphate ions published previously [1]. Experiments in the Data article represent supporting material for our work published recently [1], which described the assembly mechanism of recombinant eADF4(C16 fibrils.

  10. Selective inhibition of aggregation/fibrillation of bovine serum albumin by osmolytes: Mechanistic and energetics insights.

    Directory of Open Access Journals (Sweden)

    Moumita Dasgupta

    Full Text Available Bovine serum albumin (BSA is an important transport protein of the blood and its aggregation/fibrillation would adversely affect its transport ability leading to metabolic disorder. Therefore, understanding the mechanism of fibrillation/aggregation of BSA and design of suitable inhibitor molecules for stabilizing its native conformation, are of utmost importance. The qualitative and quantitative aspects of the effect of osmolytes (proline, hydroxyproline, glycine betaine, sarcosine and sorbitol on heat induced aggregation/fibrillation of BSA at physiological pH (pH 7.4 have been studied employing a combination of fluorescence spectroscopy, Rayleigh scattering, isothermal titration calorimetry (ITC, dynamic light scattering (DLS and transmission electron microscopy (TEM. Formation of fibrils by BSA under the given conditions was confirmed from increase in fluorescence emission intensities of Thioflavin T over a time period of 600 minutes and TEM images. Absence of change in fluorescence emission intensities of 8-Anilinonaphthalene-1-sulfonic acid (ANS in presence of native and aggregated BSA signify the absence of any amorphous aggregates. ITC results have provided important insights on the energetics of interaction of these osmolytes with different stages of the fibrillar aggregates of BSA, thereby suggesting the possible modes/mechanism of inhibition of BSA fibrillation by these osmolytes. The heats of interaction of the osmolytes with different stages of fibrillation of BSA do not follow a trend, suggesting that the interactions of stages of BSA aggregates are osmolyte specific. Among the osmolytes used here, we found glycine betaine to be supporting and promoting the aggregation process while hydroxyproline to be maximally efficient in suppressing the fibrillation process of BSA, followed by sorbitol, sarcosine and proline in the following order of their decreasing potency: Hydroxyproline> Sorbitol> Sarcosine> Proline> Glycine betaine.

  11. Small passenger car transmission test; Chevrolet LUV transmission

    Science.gov (United States)

    Bujold, M. P.

    1980-01-01

    A 1978 Chevrolet LUV manual transmission tested per the applicable portions of a passenger car automatic transmission test code (SAE J65lb) which required drive performance, coast performance, and no load test conditions. Under these test conditions, the transmission attained maximum efficiencies in the upper ninety percent range for both drive performance tests and coast performance tests. The major results of this test (torque, speed, and efficiency curves) are presented. Graphs map the complete performance characteristics for the Chevrolet LUV transmission.

  12. Fibril assembly in whey protein mixtures

    NARCIS (Netherlands)

    Bolder, S.G.

    2007-01-01

    The objective of this thesis was to study fibril assembly in mixtures of whey proteins. The effect of the composition of the protein mixture on the structures and the resulting phase behaviour was investigated. The current work has shown that beta-lactoglobulin is responsible for the fibril assembly

  13. Viscoelastic behavior of discrete human collagen fibrils

    DEFF Research Database (Denmark)

    Svensson, Rene; Hassenkam, Tue; P, Hansen

    2010-01-01

    on the strain. The slope of the viscous response showed a strain rate dependence corresponding to a power function of powers 0.242 and 0.168 for the two patellar tendon fibrils, respectively. In conclusion, the present work provides direct evidence of viscoelastic behavior at the single fibril level, which has...

  14. Mapping out the multistage fibrillation of glucagon

    DEFF Research Database (Denmark)

    Ghodke, Shirin; Nielsen, Søren B.; Christiansen, Gunna

    2012-01-01

    The 29‐residue peptide hormone glucagon forms many different morphological types of amyloid‐like fibrils, depending on solvent conditions. Here, we combine time‐series far‐UV CD with singular value decomposition analysis to reveal six different conformational states populated during fibrillation ...

  15. The Atrial Fibrillation Ablation Pilot Study

    DEFF Research Database (Denmark)

    Arbelo, Elena; Brugada, Josep; Hindricks, Gerhard

    2014-01-01

    AIMS: The Atrial Fibrillation Ablation Pilot Study is a prospective registry designed to describe the clinical epidemiology of patients undergoing an atrial fibrillation (AFib) ablation, and the diagnostic/therapeutic processes applied across Europe. The aims of the 1-year follow-up were to analy...

  16. Synthesis of Self-assembled Noble Metal Nanoparticle Chains Using Amyloid Fibrils of Lysozyme as Templates

    Directory of Open Access Journals (Sweden)

    Ziming Xu

    2016-01-01

    Full Text Available We reported a facile method for preparing self-assembled noble metal nanoparticle chains by using lysozyme amyloid fibrils as a biotemplate in an aqueous environ‐ ment. The nanoparticle chains of gold (AuNPCs, palladi‐ um (PdNPCs, platinum (PtNPCs and rhodium (RhNPCs, which are lysozyme fibrils coated by gold, palladium, platinum and rhodium nanoparticles, can be fabricated by simply reducing the corresponding metal salt precursors using NaBH4. Under the same molar ratio between salt precursors and fibrils, two types of morphologies of high- yield AuNPCs (thin- and thick- AuNPCs were synthesized as a result of adjusting the fibrosis time and temperature in the final stage. Abundant PdNPCs with a length of several micrometres intertwisted with each other to form PdNPC networks. The growth of RhNPCs started from the inner surface of the fibrils and gradually spread to the whole fibre as superabundant rhodium nanoparticles (RhNPs bound to the fibrils. Finally, PtNPCs at different growing periods were presented. The nanostructures were investigated by transmission electron microscope, UV-visible spectrosco‐ py, fluorescence spectroscopy, energy-dispersive X-ray spectroscopy and atomic force microscope.

  17. Cetirizine-Induced atrial fibrillation

    Directory of Open Access Journals (Sweden)

    Altuğ Osken

    2016-01-01

    Full Text Available Atrial fibrillation (AF is the most common observed arrhythmia in clinical practice. In the literature, AF events associated with drug induction are available. Cetirizine is a second-generation histamine antagonist used in the treatment of allergies, angioedema, and urticaria. We wish to present an atypical case who took cetirizine medication for relieving symptoms of upper tract respiratory system infection, experienced rapid ventricular response AF and treated successfully. To best of our knowledge, this is the first case of cetirizine-induced AF.

  18. A Peptide Derived from the HIV-1 gp120 Coreceptor-Binding Region Promotes Formation of PAP248-286 Amyloid Fibrils to Enhance HIV-1 Infection.

    Directory of Open Access Journals (Sweden)

    Jinquan Chen

    Full Text Available Semen is a major vehicle for HIV transmission. Prostatic acid phosphatase (PAP fragments, such as PAP248-286, in human semen can form amyloid fibrils to enhance HIV infection. Other endogenous or exogenous factors present during sexual intercourse have also been reported to promote the formation of seminal amyloid fibrils.Here, we demonstrated that a synthetic 15-residue peptide derived from the HIV-1 gp120 coreceptor-binding region, designated enhancing peptide 2 (EP2, can rapidly self-assemble into nanofibers. These EP2-derivated nanofibers promptly accelerated the formation of semen amyloid fibrils by PAP248-286, as shown by Thioflavin T (ThT and Congo red assays. The amyloid fibrils presented similar morphology, assessed via transmission electron microscopy (TEM, in the presence or absence of EP2. Circular dichroism (CD spectroscopy revealed that EP2 accelerates PAP248-286 amyloid fibril formation by promoting the structural transition of PAP248-286 from a random coil into a cross-β-sheet. Newly formed semen amyloid fibrils effectively enhanced HIV-1 infection in TZM-bl cells and U87 cells by promoting the binding of HIV-1 virions to target cells.Nanofibers composed of EP2 promote the formation of PAP248-286 amyloid fibrils and enhance HIV-1 infection.

  19. Atrial fibrillation after cardiac surgery

    Directory of Open Access Journals (Sweden)

    Nair Suresh

    2010-01-01

    Full Text Available Once considered as nothing more than a nuisance after cardiac surgery, the importance of postoperative atrial fibrillation (POAF has been realized in the last decade, primarily because of the morbidity associated with the condition. Numerous causative factors have been described without any single factor being singled out as the cause of this complication. POAF has been associated with stroke, renal failure and congestive heart failure, although it is difficult to state whether POAF is directly responsible for these complications. Guidelines have been formulated for prevention of POAF. However, very few cardiothoracic centers follow any form of protocol to prevent POAF. Routine use of prophylaxis would subject all patients to the side effects of anti-arrhythmic drugs, while only a minority of the patients do actually develop this problem postoperatively. Withdrawal of beta blockers in the postoperative period has been implicated as one of the major causes of POAF. Amiodarone, calcium channel blockers and a variety of other pharmacological agents have been used for the prevention of POAF. Atrial pacing is a non-pharmacological measure which has gained popularity in the prevention of POAF. There is considerable controversy regarding whether rate control is superior to rhythm control in the treatment of established atrial fibrillation (AF. Amiodarone plays a central role in both rate control and rhythm control in postoperative AF. Newer drugs like dronedarone and ranazoline are likely to come into the market in the coming years.

  20. Management and prognosis of atrial fibrillation in the diabetic patient

    DEFF Research Database (Denmark)

    Pallisgaard, Jannik Langtved; Lindhardt, Tommi Bo; Olesen, Jonas Bjerring

    2015-01-01

    The global burden of atrial fibrillation and diabetes mellitus (diabetes) is considerable, and prevalence rates are increasing. Diabetes is associated with an increased risk of developing atrial fibrillation; however, diabetes also influences the management and prognosis of atrial fibrillation. I...... and outcomes of heart failure and the success rates of both ablation and cardioversion in atrial fibrillation patients with diabetes. Finally, this article describes the association of HbA1c levels with the management and prognosis of atrial fibrillation patients.......The global burden of atrial fibrillation and diabetes mellitus (diabetes) is considerable, and prevalence rates are increasing. Diabetes is associated with an increased risk of developing atrial fibrillation; however, diabetes also influences the management and prognosis of atrial fibrillation....... In the following article, the authors describe the association between diabetes and atrial fibrillation; specifically, the significance of diabetes on the risk of atrial fibrillation, ischemic stroke and bleeding complications associated with anticoagulation. In addition, the authors evaluate the risks...

  1. Atrial fibrillation and survival in colorectal cancer

    Directory of Open Access Journals (Sweden)

    Justin Timothy A

    2004-11-01

    Full Text Available Abstract Background Survival in colorectal cancer may correlate with the degree of systemic inflammatory response to the tumour. Atrial fibrillation may be regarded as an inflammatory complication. We aimed to determine if atrial fibrillation is a prognostic factor in colorectal cancer. Patients and methods A prospective colorectal cancer patient database was cross-referenced with the hospital clinical-coding database to identify patients who had underwent colorectal cancer surgery and were in atrial fibrillation pre- or postoperatively. Results A total of 175 patients underwent surgery for colorectal cancer over a two-year period. Of these, 13 patients had atrial fibrillation pre- or postoperatively. Atrial fibrillation correlated with worse two-year survival (p = 0.04; log-rank test. However, in a Cox regression analysis, atrial fibrillation was not significantly associated with survival. Conclusion The presence or development of atrial fibrillation in patients undergoing surgery for colorectal cancer is associated with worse overall survival, however it was not found to be an independent factor in multivariate analysis.

  2. Preparation and Loading Process of Single Crystalline Samples into a Gas Environmental Cell Holder for In Situ Atomic Resolution Scanning Transmission Electron Microscopic Observation.

    Science.gov (United States)

    Straubinger, Rainer; Beyer, Andreas; Volz, Kerstin

    2016-06-01

    A reproducible way to transfer a single crystalline sample into a gas environmental cell holder for in situ transmission electron microscopic (TEM) analysis is shown in this study. As in situ holders have only single-tilt capability, it is necessary to prepare the sample precisely along a specific zone axis. This can be achieved by a very accurate focused ion beam lift-out preparation. We show a step-by-step procedure to prepare the sample and transfer it into the gas environmental cell. The sample material is a GaP/Ga(NAsP)/GaP multi-quantum well structure on Si. Scanning TEM observations prove that it is possible to achieve atomic resolution at very high temperatures in a nitrogen environment of 100,000 Pa.

  3. Spectroscopic study of Alzheimer's amyloid fibrils using terahertz time domain spectroscopy

    International Nuclear Information System (INIS)

    Jung, Euna; Kim, Jeonghoi; Han, Younho; Moon, Kiwon; Lim, Meehyun; Han, Haewook; Park, Joonhyuck; Kim, Sungjee

    2008-01-01

    Alzheimer's disease, one of the most common neurodegenerative diseases, is characterized by extensive amyloid deposition. Amyloid deposits contain the abundant fibrils formed by amyloid β protein (Aβ). Because amyloid fibrils are associated with amyloid diseases, including Alzheimer's disease, type 2 diabetes, prion disease, Parkinson's disease, senile systemic amyloidosis and Huntington's disease, there has been considerable interest within the biomedical and biochemical research communities. In transmission electron microscopic (TEM)images, amyloid firils are 0.1∼10μm long and approximately 10nm wide. Amyloid fibrils commonly exhibit self assembled filaments, often described as twisted or parallel assemblies of finer protofilaments. They are formed by the spontaneous aggregation of a wide variety of peptides and proteins. Structural studies of amyloid fibrils have revealed that the common structural motif of virtually all amyloid fibrils consists of cross β sheets in which the peptide strands are arranged perpendicular to the long axis of the fiber. But little was known until recently about the molecular level structures of amyloid fibils. Therefore, spectroscopic investigation of both amyloid fibrils and Aβ at the molecular level can provide the significant evidence for the molecular understanding of amyloidogenesis and for the development of innovative therapeutic and diagnostic approaches. We used terahertz time domain spectroscopy (THz TDS)to investigate both Aβ and amyloid fibril. THz TDS, developed over the last two decades, is a powerful tool to extract the properties of biomaterials and provides unique spectral signatures of biomolecules within 0.1∼10THz, which exists between microwave and infrared frequency range. Current interest in THz radiation arises from its capability of probing the delocalized collective vibrational modes in proteins. Studying the collective modes of proteins in THz frequency range can play an

  4. Spectroscopic study of Alzheimer's amyloid fibrils using terahertz time domain spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Euna; Kim, Jeonghoi; Han, Younho; Moon, Kiwon; Lim, Meehyun; Han, Haewook; Park, Joonhyuck; Kim, Sungjee [POSTECH, Pohang (Korea, Republic of)

    2008-11-15

    Alzheimer's disease, one of the most common neurodegenerative diseases, is characterized by extensive amyloid deposition. Amyloid deposits contain the abundant fibrils formed by amyloid β protein (Aβ). Because amyloid fibrils are associated with amyloid diseases, including Alzheimer's disease, type 2 diabetes, prion disease, Parkinson's disease, senile systemic amyloidosis and Huntington's disease, there has been considerable interest within the biomedical and biochemical research communities. In transmission electron microscopic (TEM)images, amyloid firils are 0.1∼10μm long and approximately 10nm wide. Amyloid fibrils commonly exhibit self assembled filaments, often described as twisted or parallel assemblies of finer protofilaments. They are formed by the spontaneous aggregation of a wide variety of peptides and proteins. Structural studies of amyloid fibrils have revealed that the common structural motif of virtually all amyloid fibrils consists of cross β sheets in which the peptide strands are arranged perpendicular to the long axis of the fiber. But little was known until recently about the molecular level structures of amyloid fibils. Therefore, spectroscopic investigation of both amyloid fibrils and Aβ at the molecular level can provide the significant evidence for the molecular understanding of amyloidogenesis and for the development of innovative therapeutic and diagnostic approaches. We used terahertz time domain spectroscopy (THz TDS)to investigate both Aβ and amyloid fibril. THz TDS, developed over the last two decades, is a powerful tool to extract the properties of biomaterials and provides unique spectral signatures of biomolecules within 0.1∼10THz, which exists between microwave and infrared frequency range. Current interest in THz radiation arises from its capability of probing the delocalized collective vibrational modes in proteins. Studying the collective modes of proteins in THz frequency range can play an

  5. In vitro tendon tissue development from human fibroblasts demonstrates collagen fibril diameter growth associated with a rise in mechanical strength

    DEFF Research Database (Denmark)

    Herchenhan, Andreas; Bayer, Monika L; Svensson, René B

    2013-01-01

    Collagen-rich tendons and ligaments are important for joint stability and force transmission, but the capacity to form new tendon is poorly understood. In the present study, we investigated mechanical strength, fibril size, and structure during development of tendon-like tissue from adult human...

  6. Psychosomatic correlations in atrial fibrillations

    Directory of Open Access Journals (Sweden)

    Vladimir Ernstovich Medvedev

    2011-01-01

    Full Text Available Patients with atrial fibrillations (AF and comorbid mental disorders were examined. Two patient groups differing in the structure of psychosomatic ratios were identified. Group 1 comprised patients with AF and signs of reactivity lability that manifested itself as psychopathological reactions to the primary manifestations of AF; Group 2 included those who had developed mental disorders mainly in end-stage cardiovascular disease (predominantly a permanent form of AF in the presence of such events as chronic heart failure (CHF. The results of the study suggest that the patients with AF have frequently anxiety and hypochondriacal disorders, which agrees with the data available in the literature. In addition, end-stage AF is marked by depressive syndromes caused by the severe course of cardiovascular diseases resulting in CHF.

  7. [Relations between FANS, PPI and atrial fibrillation].

    Science.gov (United States)

    Ricci, Fabrizio; De Caterina, Raffaele

    2013-05-01

    Recent evidence supports the existence of an association between the use of non-steroidal anti-inflammatory drugs and the risk of atrial fibrillation. Anti-inflammatory drugs are widely used for the treatment of systemic inflammatory disorders, and chronic inflammation is a well-known risk factor for the development of myocardial fibrosis. The latter accounts for atrial inhomogeneities of conduction, thus triggering and perpetuating atrial fibrillation. Atrial inflammatory remodeling may therefore be responsible for the higher incidence of atrial fibrillation among patients assuming steroidal and non-steroidal anti-inflammatory drugs because of an underlying inflammatory disorders. Alternative theories contemplate gastroesophageal reflux, which is extremely common during the use of non-steroidal anti-inflammatory drugs and may trigger atrial fibrillation, as mediating the above-mentioned association.

  8. Atrial Fibrillation During an Exploration Class Mission

    Science.gov (United States)

    Lipsett, Mark; Hamilton, Douglas; Lemery, Jay; Polk, James

    2011-01-01

    This slide presentation reviews a possible scenario of an astronaut having Atrial Fibrillation during a Mars Mission. In the case review the presentation asks several questions about the alternatives for treatment, medications and the ramifications of the decisions.

  9. SAS-Based Studies of Protein Fibrillation

    DEFF Research Database (Denmark)

    Marasini, Carlotta; Vestergaard, Bente

    2017-01-01

    .Small angle scattering is an optimal method for structural studies of the fibrillation process in order to further the knowledge of the associated diseases. The recorded scattering data include the scattering contribution of all the species in solution and must be decomposed to enable structural modeling...... of the individual components involved during the fibrillation, notably without physical separation of the species. In this chapter we explain how to optimize a small angle scattering analysis of the fibrillation process and the basic principles behind analysis of the data. We include several practical tips......Protein fibrillation is associated with a number of fatal amyloid diseases (e.g. Alzheimer's and Parkinson's diseases). From a structural point of view, the aggregation process starts from an ensemble of native states that convert into transiently formed oligomers, higher order assemblies...

  10. Salbutamol Abuse is Associated with Ventricular Fibrillation

    Directory of Open Access Journals (Sweden)

    Emin UYSAL

    2015-06-01

    Full Text Available SUMMARY: Salbutamol-induced cardiac complications are well-established. Herein, we describe a case of a 24-year female who was admitted to the emergency department because of a suicide attempt with salbutamol (76 mg. Salbutamol abuse induced the development of supraventricular tachycardia and ventricular fibrillation. Regular sinus rhythm was restored with defibrillation. The hypokalemic patient who stayed in the intensive care unit was discharged after 48 hours of hospitalization. Key words: Salbutamol, suicide, ventricular fibrillation

  11. Small passenger car transmission test: Mercury Lynx ATX transmission

    Energy Technology Data Exchange (ETDEWEB)

    Bujold, M P

    1981-09-01

    The small passenger car transmission test was initiated to supply electric vehicle manufacturers with technical information regarding the performance of commercially available transmissions. This information would enable EV manufacturers to design a more energy efficient vehicle. With this information the manufacturers would be able to estimate vehicle driving range as well as speed and torque requirements for specific road load performance characteristics. This report covers the 1981 Mercury Lynx ATX transaxle. This transmission was tested per a passenger car automatic transmission test code (SAE J65lb) which required drive performance, coast performance, and no load test conditions. Under these test conditions the transmission attained maximum efficiencies in the 93% range for drive performance tests. The major results of this test are the torque, speed and efficiency curves which are located in the data section of this report. These graphs map performance characteristics for the Mercury Lynx ATX transmission.

  12. Small passenger car transmission test-Chevrolet 200 transmission

    Science.gov (United States)

    Bujold, M. P.

    1980-01-01

    The small passenger car transmission was tested to supply electric vehicle manufacturers with technical information regarding the performance of commerically available transmissions which would enable them to design a more energy efficient vehicle. With this information the manufacturers could estimate vehicle driving range as well as speed and torque requirements for specific road load performance characteristics. A 1979 Chevrolet Model 200 automatic transmission was tested per a passenger car automatic transmission test code (SAE J651b) which required drive performance, coast performance, and no load test conditions. The transmission attained maximum efficiencies in the mid-eighty percent range for both drive performance tests and coast performance tests. Torque, speed and efficiency curves map the complete performance characteristics for Chevrolet Model 200 transmission.

  13. How Glycosaminoglycans Promote Fibrillation of Salmon Calcitonin*

    Science.gov (United States)

    Malmos, Kirsten Gade; Bjerring, Morten; Jessen, Christian Moestrup; Nielsen, Erik Holm Toustrup; Poulsen, Ebbe T.; Christiansen, Gunna; Vosegaard, Thomas; Skrydstrup, Troels; Enghild, Jan J.; Pedersen, Jan Skov; Otzen, Daniel E.

    2016-01-01

    Glycosaminoglycans (GAGs) bind all known amyloid plaques and help store protein hormones in (acidic) granular vesicles, but the molecular mechanisms underlying these important effects are unclear. Here we investigate GAG interactions with the peptide hormone salmon calcitonin (sCT). GAGs induce fast sCT fibrillation at acidic pH and only bind monomeric sCT at acidic pH, inducing sCT helicity. Increasing GAG sulfation expands the pH range for binding. Heparin, the most highly sulfated GAG, binds sCT in the pH interval 3–7. Small angle x-ray scattering indicates that sCT monomers densely decorate and pack single heparin chains, possibly via hydrophobic patches on helical sCT. sCT fibrillates without GAGs, but heparin binding accelerates the process by decreasing the otherwise long fibrillation lag times at low pH and accelerates fibril growth rates at neutral pH. sCT·heparin complexes form β-sheet-rich heparin-covered fibrils. Solid-state NMR reveals that heparin does not alter the sCT fibrillary core around Lys11 but makes changes to Val8 on the exterior side of the β-strand, possibly through contacts to Lys18. Thus GAGs significantly modulate sCT fibrillation in a pH-dependent manner by interacting with both monomeric and aggregated sCT. PMID:27281819

  14. Collagen Fibrils: Nature's Highly Tunable Nonlinear Springs.

    Science.gov (United States)

    Andriotis, Orestis G; Desissaire, Sylvia; Thurner, Philipp J

    2018-03-21

    Tissue hydration is well known to influence tissue mechanics and can be tuned via osmotic pressure. Collagen fibrils are nature's nanoscale building blocks to achieve biomechanical function in a broad range of biological tissues and across many species. Intrafibrillar covalent cross-links have long been thought to play a pivotal role in collagen fibril elasticity, but predominantly at large, far from physiological, strains. Performing nanotensile experiments of collagen fibrils at varying hydration levels by adjusting osmotic pressure in situ during atomic force microscopy experiments, we show the power the intrafibrillar noncovalent interactions have for defining collagen fibril tensile elasticity at low fibril strains. Nanomechanical tensile tests reveal that osmotic pressure increases collagen fibril stiffness up to 24-fold in transverse (nanoindentation) and up to 6-fold in the longitudinal direction (tension), compared to physiological saline in a reversible fashion. We attribute the stiffening to the density and strength of weak intermolecular forces tuned by hydration and hence collagen packing density. This reversible mechanism may be employed by cells to alter their mechanical microenvironment in a reversible manner. The mechanism could also be translated to tissue engineering approaches for customizing scaffold mechanics in spatially resolved fashion, and it may help explain local mechanical changes during development of diseases and inflammation.

  15. Lower strength of the human posterior patellar tendon seems unrelated to mature collagen cross-linking and fibril morphology

    DEFF Research Database (Denmark)

    Hansen, Philip; Haraldsson, Bjarki Thor; Aagaard, Per

    2010-01-01

    The human patellar tendon is frequently affected by tendinopathy, but the etiology of the condition is not established, although differential loading of the anterior and posterior tendon may be associated with the condition. We hypothesized that changes in fibril morphology and collagen cross...

  16. RR-Interval variance of electrocardiogram for atrial fibrillation detection

    Science.gov (United States)

    Nuryani, N.; Solikhah, M.; Nugoho, A. S.; Afdala, A.; Anzihory, E.

    2016-11-01

    Atrial fibrillation is a serious heart problem originated from the upper chamber of the heart. The common indication of atrial fibrillation is irregularity of R peak-to-R-peak time interval, which is shortly called RR interval. The irregularity could be represented using variance or spread of RR interval. This article presents a system to detect atrial fibrillation using variances. Using clinical data of patients with atrial fibrillation attack, it is shown that the variance of electrocardiographic RR interval are higher during atrial fibrillation, compared to the normal one. Utilizing a simple detection technique and variances of RR intervals, we find a good performance of atrial fibrillation detection.

  17. Curcumin Protects β-Lactoglobulin Fibril Formation and Fibril-Induced Neurotoxicity in PC12 Cells.

    Directory of Open Access Journals (Sweden)

    Mansooreh Mazaheri

    Full Text Available In this study the β-lactoglobulin fibrillation, in the presence or absence of lead ions, aflatoxin M1 and curcumin, was evaluated using ThT fluorescence, Circular dichroism spectroscopy and atomic force microscopy. To investigate the toxicity of the different form of β-Lg fibrils, in the presence or absence of above toxins and curcumin, we monitored changes in the level of reactive oxygen species and morphology of the differentiated neuron-like PC12 cells. The cell viability, cell body area, average neurite length, neurite width, number of primary neurites, percent of bipolar cells and node/primary neurite ratios were used to assess the growth and complexity of PC12 cells exposed to different form of β-Lg fibrils. Incubation of β-Lg with curcumin resulted in a significant decrease in ROS levels even in the presence of lead ions and aflatoxin M1. The β-Lg fibrils formed in the presence of lead ions and aflatoxin M1 attenuated the growth and complexity of PC12 cells compared with other form of β-Lg fibrils. However, the adverse effects of these toxins and protein fibrils were negated in the presence of curcumin. Furthermore, the antioxidant and inhibitory effects of curcumin protected PC12 cells against fibril neurotoxicity and enhanced their survival. Thus, curcumin may provide a protective effect toward β-Lg, and perhaps other protein, fibrils mediated neurotoxicity.

  18. Oxidation reduces the fibrillation but not the neurotoxicity of the prion peptide PrP106-126

    DEFF Research Database (Denmark)

    Bergstrøm, Linda Alice; Chabry, J.; Bastholm, L.

    2007-01-01

    There is increasing evidence that soluble oligomers of misfolded protein may play a role in the pathogenesis of protein misfolding diseases including the transmissible spongiform encephalopathies (TSE) where the protein involved is the prion protein, PrP. The effect of oxidation on fibrillation...... tendency and neurotoxicity of different molecular variants of the prion peptide PrP106-126 was investigated. It was found that methionine oxidation significantly reduced amyloid fibril formation and proteinase K resistance, but it did not reduce (but rather increase slightly) the neurotoxicity...

  19. Immobilization of organophosphate hydrolase on an amyloid fibril nanoscaffold: towards bioremediation and chemical detoxification.

    Science.gov (United States)

    Raynes, Jared K; Pearce, F Grant; Meade, Susie J; Gerrard, Juliet A

    2011-01-01

    Organophosphate hydrolase has potential as a bioremediation and chemical detoxification enzyme, but the problems of reusability and stability need to be addressed to use this enzyme on an industrial scale. Immobilizing the enzyme to a nanoscaffold may help to solve these problems. Amyloid fibrils generated from insulin and crystallin provided a novel nanoscaffold for the immobilization of organophosphate hydrolase, using glutaraldehyde as the crosslinking reagent. Electrophoretic, centrifugation, and temperature stability experiments, together with transmission electron microscopy were undertaken to verify that crosslinking had successfully occurred. The resulting fibrils remained active towards the substrate paraoxon and when immobilized to the insulin amyloid fibrils, the enzyme exhibited a significant (∼ 300%) increase in the relative temperature stability at 40, 45, and 50°C (as measured by comparing the initial enzyme activity to the activity remaining after heating), compared to free enzyme. This confirms that amyloid fibrils could provide a new type of nanoscaffold for enzyme immobilization. Copyright © 2010 American Institute of Chemical Engineers (AIChE).

  20. Pulmonary cellular effects in rats following aerosol exposures to ultrafine Kevlar aramid fibrils: evidence for biodegradability of inhaled fibrils.

    Science.gov (United States)

    Warheit, D B; Kellar, K A; Hartsky, M A

    1992-10-01

    Previous chronic inhalation studies have shown that high concentrations of Kevlar fibrils produced fibrosis and cystic keratinizing tumors in rats following 2-year inhalation exposures. The current studies were undertaken to evaluate mechanisms and to assess the toxicity of inhaled Kevlar fibrils relative to other reference materials. Rats were exposed to ultrafine Kevlar fibers (fibrils) for 3 or 5 days at concentrations ranging from 600-1300 fibers/cc (gravimetric concentrations ranging from 2-13 mg/m3). A complete characterization of the fiber aerosol and dose was carried out. These measurements included gravimetric concentrations, mass median aerodynamic diameter, fiber number, and count median lengths and diameters of the aerosol. Following exposures, cells and fluids from groups of sham- and fiber-exposed animals were recovered by bronchoalveolar lavage (BAL). Alkaline phosphatase, lactate dehydrogenase (LDH), protein, and N-acetyl glucosaminidase (NAG) values were measured in BAL fluids at several time points postexposure. Alveolar macrophages were cultured and studied for morphology, chemotaxis, and phagocytosis by scanning electron microscopy. The lungs of additional exposed animals were processed for deposition, cell labeling, retained dose, and lung clearance studies, as well as fiber dimensions (from digested lung tissue), histopathology, and transmission electron microscopy. Five-day exposures to Kevlar fibrils elicited a transient granulocytic inflammatory response with concomitant increases in BAL fluid levels of alkaline phosphatase, NAG, LDH, and protein. Unlike the data from silica and asbestos exposures where inflammation persisted, biochemical parameters returned to control levels at time intervals between 1 week and 1 month postexposure. Macrophage function in Kevlar-exposed alveolar macrophages was not significantly different from sham controls at any time period. Cell labeling studies were carried out immediately after exposure, as well as 1

  1. Superficial Collagen Fibril Modulus and Pericellular Fixed Charge Density Modulate Chondrocyte Volumetric Behaviour in Early Osteoarthritis

    Directory of Open Access Journals (Sweden)

    Petri Tanska

    2013-01-01

    Full Text Available The aim of this study was to investigate if the experimentally detected altered chondrocyte volumetric behavior in early osteoarthritis can be explained by changes in the extracellular and pericellular matrix properties of cartilage. Based on our own experimental tests and the literature, the structural and mechanical parameters for normal and osteoarthritic cartilage were implemented into a multiscale fibril-reinforced poroelastic swelling model. Model simulations were compared with experimentally observed cell volume changes in mechanically loaded cartilage, obtained from anterior cruciate ligament transected rabbit knees. We found that the cell volume increased by 7% in the osteoarthritic cartilage model following mechanical loading of the tissue. In contrast, the cell volume decreased by 4% in normal cartilage model. These findings were consistent with the experimental results. Increased local transversal tissue strain due to the reduced collagen fibril stiffness accompanied with the reduced fixed charge density of the pericellular matrix could increase the cell volume up to 12%. These findings suggest that the increase in the cell volume in mechanically loaded osteoarthritic cartilage is primarily explained by the reduction in the pericellular fixed charge density, while the superficial collagen fibril stiffness is suggested to contribute secondarily to the cell volume behavior.

  2. Fourier Transform Infrared (FTIR) Spectroscopy, Ultraviolet Resonance Raman (UVRR) Spectroscopy, and Atomic Force Microscopy (AFM) for Study of the Kinetics of Formation and Structural Characterization of Tau Fibrils.

    Science.gov (United States)

    Ramachandran, Gayathri

    2017-01-01

    Kinetic studies of tau fibril formation in vitro most commonly employ spectroscopic probes such as thioflavinT fluorescence and laser light scattering or negative stain transmission electron microscopy. Here, I describe the use of Fourier transform infrared (FTIR) spectroscopy, ultraviolet resonance Raman (UVRR) spectroscopy, and atomic force microscopy (AFM) as complementary probes for studies of tau aggregation. The sensitivity of vibrational spectroscopic techniques (FTIR and UVRR) to secondary structure content allows for measurement of conformational changes that occur when the intrinsically disordered protein tau transforms into cross-β-core containing fibrils. AFM imaging serves as a gentle probe of structures populated over the time course of tau fibrillization. Together, these assays help further elucidate the structural and mechanistic complexity inherent in tau fibril formation.

  3. Spectral of electrocardiographic RR intervals to indicate atrial fibrillation

    Science.gov (United States)

    Nuryani, Nuryani; Satrio Nugroho, Anto

    2017-11-01

    Atrial fibrillation is a serious heart diseases, which is associated on the risk of death, and thus an early detection of atrial fibrillation is necessary. We have investigated spectral pattern of electrocardiogram in relation to atrial fibrillation. The utilized feature of electrocardiogram is RR interval. RR interval is the time interval between a two-consecutive R peaks. A series of RR intervals in a time segment is converted to a signal with a frequency domain. The frequency components are investigated to find the components which significantly associate to atrial fibrillation. A segment is defined as atrial fibrillation or normal segments by considering a defined number of atrial fibrillation RR in the segment. Using clinical data of 23 patients with atrial fibrillation, we find that the frequency components could be used to indicate atrial fibrillation.

  4. Interaction of magnetic nanoparticles with lysozyme amyloid fibrils

    International Nuclear Information System (INIS)

    Gdovinová, Veronika; Tomašovičová, Natália; Batko, Ivan; Batková, Marianna; Balejčíková, Lucia; Garamus, Vasyl M.; Petrenko, Viktor I.; Avdeev, Mikhail V.; Kopčanský, Peter

    2017-01-01

    This work is devoted to the structural study of complex solutions of magnetic nanoparticles with lysozyme amyloid fibrils due to possible ordering of such system by applying the external magnetic field. The interaction of magnetic nanoparticles with amyloid fibrils has been followed by atomic force microscopy and small-angle X-ray scattering. It has been observed that magnetic nanoparticles (MNPs) adsorb to lysozyme amyloid fibrils. It was found that MNPs alter amyloids structures, namely the diameter of lysozyme amyloid fibrils is increased whereas the length of fibrils is decreased. In the same time MNPs do not change the helical pitch significantly. - Highlights: • Solution of MNPs with lysozyme amyloid fibrils was characterized by AFM and SAXS. • MNPs adsorb to lysozyme amyloid fibrils. • Diameter and size of lysozyme amyloid fibrils change due to doping with MNPs.

  5. Risk of atrial fibrillation and stroke in rheumatoid arthritis

    DEFF Research Database (Denmark)

    Lindhardsen, Jesper; Ahlehoff, Ole; Gislason, Gunnar Hilmar

    2012-01-01

    To determine if patients with rheumatoid arthritis have increased risk of atrial fibrillation and stroke.......To determine if patients with rheumatoid arthritis have increased risk of atrial fibrillation and stroke....

  6. Interaction of magnetic nanoparticles with lysozyme amyloid fibrils

    Energy Technology Data Exchange (ETDEWEB)

    Gdovinová, Veronika [Institute of Experimental Physics SAS, Watsonova 47, 040 01 Košice (Slovakia); Frank Laboratory of Neutron Physics, Joint Institute for Nuclear Research, Joliot-Curie 6, 141980 Dubna, Moscow Region (Russian Federation); Tomašovičová, Natália, E-mail: nhudak@saske.sk [Institute of Experimental Physics SAS, Watsonova 47, 040 01 Košice (Slovakia); Frank Laboratory of Neutron Physics, Joint Institute for Nuclear Research, Joliot-Curie 6, 141980 Dubna, Moscow Region (Russian Federation); Batko, Ivan; Batková, Marianna; Balejčíková, Lucia [Institute of Experimental Physics SAS, Watsonova 47, 040 01 Košice (Slovakia); Garamus, Vasyl M. [Helmholtz-Zentrum Geesthacht: Zentrum fr Material, und Kstenforschung GmbH, Max-Plank-Strae 1, Geesthacht 216502 (Germany); Petrenko, Viktor I. [Frank Laboratory of Neutron Physics, Joint Institute for Nuclear Research, Joliot-Curie 6, 141980 Dubna, Moscow Region (Russian Federation); Physics Department, Taras Shevchenko Kyiv National University, Volodymyrska Street 64, 01601 Kyiv (Ukraine); Avdeev, Mikhail V. [Frank Laboratory of Neutron Physics, Joint Institute for Nuclear Research, Joliot-Curie 6, 141980 Dubna, Moscow Region (Russian Federation); Kopčanský, Peter [Institute of Experimental Physics SAS, Watsonova 47, 040 01 Košice (Slovakia)

    2017-06-01

    This work is devoted to the structural study of complex solutions of magnetic nanoparticles with lysozyme amyloid fibrils due to possible ordering of such system by applying the external magnetic field. The interaction of magnetic nanoparticles with amyloid fibrils has been followed by atomic force microscopy and small-angle X-ray scattering. It has been observed that magnetic nanoparticles (MNPs) adsorb to lysozyme amyloid fibrils. It was found that MNPs alter amyloids structures, namely the diameter of lysozyme amyloid fibrils is increased whereas the length of fibrils is decreased. In the same time MNPs do not change the helical pitch significantly. - Highlights: • Solution of MNPs with lysozyme amyloid fibrils was characterized by AFM and SAXS. • MNPs adsorb to lysozyme amyloid fibrils. • Diameter and size of lysozyme amyloid fibrils change due to doping with MNPs.

  7. Surgical Treatment of Atrial Fibrillation: A Review

    Directory of Open Access Journals (Sweden)

    Nadine Hiari

    2011-01-01

    Full Text Available Atrial fibrillation is the most commonly sustained arrhythmia in man. While it affects millions of patients worldwide, its incidence will markedly increase with an aging population. Primary goals of AF therapy are to (1 reduce embolic complications, particularly stroke, (2 alleviate symptoms, and (3 prevent long-term heart remodelling. These have been proven to be a challenge as there are major limitations in our knowledge of the pathological and electrophysiological mechanisms underlying AF. Although advances continue to be made in the medical management of this condition, pharmacotherapy is often unsuccessful. Because of the high recurrence rate of AF despite antiarrhythmic drug therapy for maintenance of sinus rhythm and the adverse effects of these drugs, there has been growing interest in nonpharmacological strategies. Surgery for treatment of AF has been around for some time. The Cox-Maze procedure is the gold standard for the surgical treatment of atrial fibrillation and has more than 90% success in eliminating atrial fibrillation. Although the cut and sew maze is very effective, it has been superseded by newer operations that rely on alternate energy sources to create lines of conduction block. In addition, the evolution of improved ablation technology and instrumentation has facilitated the development of minimally invasive approaches. In this paper, the rationale for surgical ablation for atrial fibrillation and the different surgical techniques that were developed will be explored. In addition, it will detail the new approaches to surgical ablation of atrial fibrillation that employ alternate energy sources.

  8. New-Onset Atrial Fibrillation in the Critically Ill*

    OpenAIRE

    Moss, Travis J.; Calland, James Forrest; Enfield, Kyle B.; Gomez-Manjarres, Diana C.; Ruminski, Caroline; DiMarco, John P.; Lake, Douglas E.; Moorman, J. Randall

    2017-01-01

    Objective: To determine the association of new-onset atrial fibrillation with outcomes, including ICU length of stay and survival. Design: Retrospective cohort of ICU admissions. We found atrial fibrillation using automated detection (? 90?s in 30?min) and classed as new-onset if there was no prior diagnosis of atrial fibrillation. We identified determinants of new-onset atrial fibrillation and, using propensity matching, characterized its impact on outcomes. Setting: Tertiary care academic c...

  9. Tendon and ligament fibrillar crimps give rise to left-handed helices of collagen fibrils in both planar and helical crimps.

    Science.gov (United States)

    Franchi, Marco; Ottani, Vittoria; Stagni, Rita; Ruggeri, Alessandro

    2010-03-01

    Collagen fibres in tendons and ligaments run straight but in some regions they show crimps which disappear or appear more flattened during the initial elongation of tissues. Each crimp is formed of collagen fibrils showing knots or fibrillar crimps at the crimp top angle. The present study analyzes by polarized light microscopy, scanning electron microscopy, transmission electron microscopy the 3D morphology of fibrillar crimp in tendons and ligaments of rat demonstrating that each fibril in the fibrillar region always twists leftwards changing the plane of running and sharply bends modifying the course on a new plane. The morphology of fibrillar crimp in stretched tendons fulfills the mechanical role of the fibrillar crimp acting as a particular knot/biological hinge in absorbing tension forces during fibril strengthening and recoiling collagen fibres when stretching is removed. The left-handed path of fibrils in the fibrillar crimp region gives rise to left-handed fibril helices observed both in isolated fibrils and sections of different tendons and ligaments (flexor digitorum profundus muscle tendon, Achilles tendon, tail tendon, patellar ligament and medial collateral ligament of the knee). The left-handed path of fibrils represents a new final suprafibrillar level of the alternating handedness which was previously described only from the molecular to the microfibrillar level. When the width of the twisting angle in the fibrillar crimp is nearly 180 degrees the fibrils appear as left-handed flattened helices forming crimped collagen fibres previously described as planar crimps. When fibrils twist with different subsequent rotational angles (left-helical course but, running in many different nonplanar planes, they form wider helical crimped fibres.

  10. Artificial atrial fibrillation in the dog. An artifact?

    NARCIS (Netherlands)

    Strackee, J.; Hoelen, A.J.; Zimmerman, A.N.E.; Meijler, F.L.

    R-R interval sequences during artificial atrial fibrillation in dogs were studied in the same way as in patients in a previous study and compared with results obtained in dogs with spontaneous atrial fibrillation. Artificial atrial fibrillation was effected by right atrial stimulation in three

  11. Treatment Guidelines of Atrial Fibrillation (AFib or AF)

    Science.gov (United States)

    ... Venous Thromboembolism Aortic Aneurysm More Treatment Guidelines of Atrial Fibrillation (AFib or AF) Updated:Jun 28,2017 What ... calculator This content was last reviewed July 2016. Atrial Fibrillation • Introduction • What is Atrial Fibrillation? • Why AFib Matters ...

  12. Who Is at Risk for Atrial Fibrillation (AF or AFib)?

    Science.gov (United States)

    ... Aortic Aneurysm More Who is at Risk for Atrial Fibrillation (AF or AFib)? Updated:Oct 7,2016 Are ... unique online community for people living with AFib Atrial Fibrillation • Introduction • What is Atrial Fibrillation? • Why AFib Matters ...

  13. Fibrils from designed non-amyloid-related synthetic peptides induce AA-amyloidosis during inflammation in an animal model.

    Directory of Open Access Journals (Sweden)

    Per Westermark

    Full Text Available BACKGROUND: Mouse AA-amyloidosis is a transmissible disease by a prion-like mechanism where amyloid fibrils act by seeding. Synthetic peptides with no amyloid relationship can assemble into amyloid-like fibrils and these may have seeding capacity for amyloid proteins. PRINCIPAL FINDINGS: Several synthetic peptides, designed for nanotechnology, have been examined for their ability to produce fibrils with Congo red affinity and concomitant green birefringence, affinity for thioflavin S and to accelerate AA-amyloidosis in mice. It is shown that some amphiphilic fibril-forming peptides not only produced Congo red birefringence and showed affinity for thioflavin S, but they also shortened the lag phase for systemic AA-amyloidosis in mice when they were given intravenously at the time of inflammatory induction with silver nitride. Peptides, not forming amyloid-like fibrils, did not have such properties. CONCLUSIONS: These observations should caution researchers and those who work with synthetic peptides and their derivatives to be aware of the potential health concerns.

  14. Transmission reliability faces future challenges

    International Nuclear Information System (INIS)

    Beaty, W.

    1993-01-01

    The recently published Washington International Energy Group's 1993 Electric Utility Outlook states that nearly one-third (31 percent) of U.S. utility executives expect reliability to decrease in the near future. Electric power system stability is crucial to reliability. Stability analysis determines whether a system will stay intact under normal operating conditions, during minor disturbances such as load fluctuations, and during major disturbances when one or more parts of the system fails. All system elements contribute to reliability or the lack of it. However, this report centers on the transmission segment of the electric system. The North American Electric Reliability Council (NERC) says the transmission systems as planned will be adequate over the next 10 years. However, delays in building new lines and increasing demands for transmission services are serious concerns. Reliability concerns exist in the Mid-Continent Area Power Pool and the Mid-America Interconnected Network regions where transmission facilities have not been allowed to be constructed as planned. Portions of the transmission systems in other regions are loaded at or near their limits. NERC further states that utilities must be allowed to complete planned generation and transmission as scheduled. A reliable supply of electricity also depends on adhering to established operating criteria. Factors that could complicate operations include: More interchange schedules resulting from increased transmission services. Increased line loadings in portions of the transmission systems. Proliferation of non-utility generators

  15. Antihypertensive treatment and risk of atrial fibrillation

    DEFF Research Database (Denmark)

    Marott, Sarah C W; Nielsen, Sune F; Benn, Marianne

    2014-01-01

    on ARB monotherapy were matched 1:1 with individuals on β-blocker (n = 20 566), diuretic (n = 20 832), calcium-antagonist (n = 20 232), and ACEi monotherapy (n = 20 158). All were free of atrial fibrillation and of predisposing diseases like heart failure, ischaemic heart disease, diabetes mellitus......, and hyperthyroidism at baseline and none received any other antihypertensive medication. We studied risk of atrial fibrillation, and used risk of stroke, influenced by lowering blood pressure rather than renin-angiotensin system blockade per se, as an indicator of the importance of blood pressure lowering per se...... of stroke did not differ among the five antihypertensive medications. CONCLUSION: Use of ACEis and ARBs compared with β-blockers and diuretics associates with a reduced risk of atrial fibrillation, but not stroke, within the limitations of a retrospective study reporting associations. This suggests...

  16. A continuum model for hierarchical fibril assembly

    Science.gov (United States)

    van Lith, B. S.; Muntean, A.; Storm, C.

    2014-06-01

    Most of the biological polymers that make up our cells and tissues are hierarchically structured. For biopolymers ranging from collagen, to actin, to fibrin and amyloid fibrils this hierarchy provides vitally important versatility. The structural hierarchy must be encoded in the self-assembly process, from the earliest stages onward, in order to produce the appropriate substructures. In this letter, we explore the kinetics of multistage self-assembly processes in a model system which allows comparison to bulk probes such as light scattering. We apply our model to recent turbidimetry data on the self-assembly of collagen fibrils. Our analysis suggests a connection between diffusion-limited aggregation kinetics and fibril growth, supported by slow, power-law growth at very long time scales.

  17. Alcohol consumption and risk of atrial fibrillation

    DEFF Research Database (Denmark)

    Tolstrup, Janne Schurmann; Wium-Andersen, Marie Kim; Ørsted, David Dynnes

    2016-01-01

    BACKGROUND: The aim of this study was to test the hypothesis that alcohol consumption, both observational (self-reported) and estimated by genetic instruments, is associated with a risk of atrial fibrillation and to determine whether people with high cardiovascular risk are more sensitive towards...... alcohol than people with low risk. METHODS: We used data for a total of 88,782 men and women from the Copenhagen City Heart Study 1991-1994 and 2001-2003 and the Copenhagen General Population Study 2003-2010. Information on incident cases of atrial fibrillation was obtained from a validated nationwide...... register. As a measure of alcohol exposure, both self-reported consumption and genetic variations in alcohol metabolizing genes (ADH1B/ADH1C) were used as instrumental variables. The endpoint was admission to hospital for atrial fibrillation as recorded in a validated hospital register. RESULTS: A total...

  18. Sucrose modulates insulin amyloid-like fibril formation: effect on the aggregation mechanism and fibril morphology

    DEFF Research Database (Denmark)

    Marasini, Carlotta; Foderà, Vito; Vestergaard, Bente

    2017-01-01

    Co-solutes, such as sugars, are used in in vitro protein aggregation experiments to mimic crowding and, in general, complex environments. Sugars often increase the stability of the native protein structure by affecting inter- and intramolecular protein–protein interactions. This, in turn, modifies...... in a delay of the onset of fibrillation. Moreover, it leads to a dramatic change in both the morphology and overall amount of fibrils. Our results emphasize that the detailed composition of protein surroundings likely influences not only the fibrillation kinetics but also the balance between different...

  19. Atrial fibrillation and the 4P medicine.

    Science.gov (United States)

    Censi, Federica; Cianfrocca, Cinzia; Purificato, Ivana

    2013-01-01

    Although the paradigm of the 4P medicine - Predictive, Personalized, Preemptive, and Participatory - has been suggested several years ago, its application to atrial fibrillation is still far away. Given the increasing prevalence and incidence of this pathology it is the time to promote preventive strategies, by identifying the risk factors associated to life style and by incentivizing innovative diagnostic technologies. The promotion of the correct life style and of the use of diagnostic devices based on innovative and reliable technologies, represent a first step towards the full realization of the revolution of 4P medicine in atrial fibrillation.

  20. Atrial fibrillation and the 4P medicine

    Directory of Open Access Journals (Sweden)

    Federica Censi

    2013-09-01

    Full Text Available Although the paradigm of the 4P medicine - Predictive, Personalized, Preemptive, and Participatory - has been suggested several years ago, its application to atrial fibrillation is still far away. Given the increasing prevalence and incidence of this pathology it is the time to promote preventive strategies, by identifying the risk factors associated to life style and by incentivizing innovative diagnostic technologies. The promotion of the correct life style and of the use of diagnostic devices based on innovative and reliable technologies, represent a first step towards the full realization of the revolution of 4P medicine in atrial fibrillation.

  1. Double sequential defibrillation for refractory ventricular fibrillation.

    Science.gov (United States)

    El Tawil, Chady; Mrad, Sandra; Khishfe, Basem F

    2017-12-01

    A 54-year-old suffered from an out-of-hospital cardiac arrest. Compressions were started within minutes and the patient was in refractory ventricular fibrillation despite multiple asynchronized shocks and maximal doses of antiarrhythmic agents. Double sequential defibrillation was attempted with successful Return Of Spontaneous Circulation (ROSC) after a total of 61min of cardiac arrest. The patient was discharged home neurologically intact. Double sequential defibrillation could be a simple effective approach to patients with refractory ventricular fibrillation. Copyright © 2017 Elsevier Inc. All rights reserved.

  2. Dynamics of Fibril Growth and Feedback Motifs

    DEFF Research Database (Denmark)

    Cordsen, Pia

    lumped and long, straight fibrils. Previous results on real time observation of fibrils were successfully reproduced using mixed conditions of both sodium dodecyl sulfate and seeds but not when using only one of the two. The dynamics of a three-species network motif, consisting of a predator and two...... which of the two competitors is better and if one of them will become extinct. Further it is found that in the range of coexistence between the two preys, the better one peaks first....

  3. Cryoballoon Catheter Ablation in Atrial Fibrillation

    Directory of Open Access Journals (Sweden)

    Cevher Ozcan

    2011-01-01

    Full Text Available Pulmonary vein isolation with catheter ablation is an effective treatment in patients with symptomatic atrial fibrillation refractory or intolerant to antiarrhythmic medications. The cryoballoon catheter was recently approved for this procedure. In this paper, the basics of cryothermal energy ablation are reviewed including its ability of creating homogenous lesion formation, minimal destruction to surrounding vasculature, preserved tissue integrity, and lower risk of thrombus formation. Also summarized here are the publications describing the clinical experience with the cryoballoon catheter ablation in both paroxysmal and persistent atrial fibrillation, its safety and efficacy, and discussions on the technical aspect of the cryoballoon ablation procedure.

  4. Our Mission Towards Atrial Fibrillation Free World

    OpenAIRE

    Lakkireddy, Dhanunjaya; Natale, Andrea

    2012-01-01

    We can hardly believe that the year 2012 has come and almost gone. What a great year this was here at the JAFIB office and all around the world. 2012 was marked by several key discoveries and fact finding missions in the Atrial Fibrillation (AF) world by various groups and individual scientists all across the globe. We are one more foot forward in our relentless mission towards a world free of Atrial Fibrillation. Congratulations one and all on your contributions in making this world a better...

  5. Atrial natriuretic peptide in patients with heart failure and chronic atrial fibrillation : Role of duration of at atrial fibrillation

    NARCIS (Netherlands)

    Van Den Berg, MP; Crijns, HJGM; Van Veldhuisen, DJ; Van Gelder, IC; De Kam, PJ; Lie, KI

    The purpose of this study was to analyze the determinants of atrial natriuretic peptide level in patients with congestive heart failure and atrial fibrillation. In particular, the duration of atrial fibrillation was analyzed because atrial fibrillation per se might have a specific effect on atrial

  6. Dependence of Self-Assembled Peptide Hydrogel Network Structure on Local Fibril Nanostructure

    Science.gov (United States)

    Hule, Rohan A.; Nagarkar, Radhika P.; Hammouda, Boualem; Schneider, Joel P.; Pochan, Darrin J.

    2011-01-01

    Physically cross-linked, fibrillar hydrogel networks are formed by the self-assembly of β-hairpin peptide molecules with varying degrees of strand asymmetry. The peptide registry in the self-assembled state can be used as a design element to generate fibrils with twisting, nontwisting, or laminated morphology. The mass density of the networks varies significantly, and can be directly related to the local fibrillar morphology as evidenced by small angle neutron scattering (SANS) and in situ substantiation using cryogenic transmission electron microscopy (cryo-TEM) under identical concentrations and conditions. Similarly, the density of the network is dependent on changes in the peptide concentration. Bulk rheological properties of the hydrogels can be correlated to the fibrillar nanostructure, with the stiffer, laminated fibrils forming networks with a higher G′ as compared to the flexible, singular fibrillar networks. PMID:21566682

  7. Transmission issues

    International Nuclear Information System (INIS)

    Bradford, J.; Wilson, L.; Thon, S.; Millar, N.

    2005-01-01

    This session on transmission issues focused on the role that transmission plays in electricity markets and the importance of getting the market structure right in terms of generation divestiture with buy back contracts, demand side responsive programs, transmission upgrades and long term contracts. The difficulties of distinguishing between market power and scarcity were examined along with some of the complications that ensue if transmission experiences congestion, as exemplified by the August 2003 blackout in eastern North America. The presentations described the best ways to handle transmission issues, and debated whether transmission should be deregulated or follow market forces. Issues of interconnections and reliability of connections were also debated along with the attempt to integrate renewables into the grid. Some presentations identified what new transmission must be built and what must be done to ensure that transmission gets built. The challenges and business opportunities for transmission in Alberta were discussed with reference to plans to invest in new infrastructure, where it is going outside of the province and how it works with other jurisdictions. Manitoba's Conawapa Hydro Project and its 2000 MW tie line to Ontario was also discussed. Some examples of non-optimal use of interconnections in Europe were also discussed in an effort to learn from these mistakes and avoid them in Canada. tabs., figs

  8. Protein disulfide isomerase interacts with tau protein and inhibits its fibrillization.

    Directory of Open Access Journals (Sweden)

    Li-Rong Xu

    Full Text Available BACKGROUND: Tau protein is implicated in the pathogenesis of neurodegenerative disorders such as tauopathies including Alzheimer disease, and Tau fibrillization is thought to be related to neuronal toxicity. Physiological inhibitors of Tau fibrillization hold promise for developing new strategies for treatment of Alzheimer disease. Because protein disulfide isomerase (PDI is both an enzyme and a chaperone, and implicated in neuroprotection against Alzheimer disease, we want to know whether PDI can prevent Tau fibrillization. In this study, we have investigated the interaction between PDI and Tau protein and the effect of PDI on Tau fibrillization. METHODOLOGY/PRINCIPAL FINDINGS: As evidenced by co-immunoprecipitation and confocal laser scanning microscopy, human PDI interacts and co-locates with some endogenous human Tau on the endoplasmic reticulum of undifferentiated SH-SY5Y neuroblastoma cells. The results from isothermal titration calorimetry show that one full-length human PDI binds to one full-length human Tau (or human Tau fragment Tau244-372 monomer with moderate, micromolar affinity at physiological pH and near physiological ionic strength. As revealed by thioflavin T binding assays, Sarkosyl-insoluble SDS-PAGE, and transmission electron microscopy, full-length human PDI remarkably inhibits both steps of nucleation and elongation of Tau244-372 fibrillization in a concentration-dependent manner. Furthermore, we find that two molecules of the a-domain of human PDI interact with one Tau244-372 molecule with sub-micromolar affinity, and inhibit both steps of nucleation and elongation of Tau244-372 fibrillization more strongly than full-length human PDI. CONCLUSIONS/SIGNIFICANCE: We demonstrate for the first time that human PDI binds to Tau protein mainly through its thioredoxin-like catalytic domain a, forming a 1∶1 complex and preventing Tau misfolding. Our findings suggest that PDI could act as a physiological inhibitor of Tau

  9. Mechanisms of atrial fibrillation: is a cure at hand?

    Science.gov (United States)

    Scheinman, M M

    2000-05-01

    The mechanisms of atrial fibrillation relate to the presence of random reentry involving multiple interatrial circuits. Triggers for development of atrial fibrillation include rapidly discharging atrial foci (mainly from pulmonary veins) or degeneration of atrial flutter or atrial tachycardia into fibrillation. Therapy for control of atrial fibrillation includes drugs, atrial pacing for those with sinus node dysfunction, or ablation of the atrioventricular junction. Therapeutic maneuvers for cure of atrial fibrillation include surgical or radiofrequency catheter induced linear lesions to reduce the atrial tissue and prevent the requisite number of reentrant wavelets. We need a much better understanding of basic mechanisms before a true cure is at hand.

  10. New risk factors for atrial fibrillation : causes of 'not-so-lone atrial fibrillation'

    NARCIS (Netherlands)

    Schoonderwoerd, Bas A.; Smit, Marcelle D.; Pen, Lucas; Van Gelder, Isabelle C.

    Atrial fibrillation (AF) is a prevalent arrhythmia in patients with cardiovascular disease. The classical risk factors for developing AF include hypertension, valvular disease, (ischaemic) cardiomyopathy, diabetes mellitus, and thyroid disease. In some patients with AF, no underlying

  11. Effect of age on stroke prevention therapy in patients with atrial fibrillation: the atrial fibrillation investigators

    DEFF Research Database (Denmark)

    van Walraven, Carl; Hart, Robert G; Connolly, Stuart

    2009-01-01

    . Outcomes included ischemic stroke, serious bleeding (intracranial hemorrhage or systemic bleeding requiring hospitalization, transfusion, or surgery), and cardiovascular events (ischemic stroke, myocardial infarction, systemic embolism, or vascular death). RESULTS: The analysis included 8932 patients......BACKGROUND AND PURPOSE: Stroke risk increases with age in patients who have nonvalvular atrial fibrillation. It is uncertain whether the efficacy of stroke prevention therapies in atrial fibrillation changes as patients age. The objective of this study was to determine the effect of age...... on the relative efficacy of oral anticoagulants (OAC) and antiplatelet (AP) therapy (including acetylsalicylic acid and triflusal) on ischemic stroke, serious bleeding, and vascular events in patients with atrial fibrillation. METHODS: This is an analysis of the Atrial Fibrillation Investigators database, which...

  12. Aspects epidemiologiques et etiologiques de la fibrillation ...

    African Journals Online (AJOL)

    Material and et methods: It was a prospective study realized during two years (1st january 2008 to 31st december 2009), relative to 143 cases hospitalized at the cardiology clinic of the campus university hospital of Lome, the authors have studied the epidemiologic and etiologic aspects of atrial fibrillation in hospital circle.

  13. Integrating new approaches to atrial fibrillation management

    DEFF Research Database (Denmark)

    Kotecha, Dipak; Breithardt, Günter; Camm, A John

    2018-01-01

    of the Atrial Fibrillation Network (AFNET) and the European Heart Rhythm Association (EHRA), held at the European Society of Cardiology Heart House in Sophia Antipolis, France, 17-19 January 2017. Sixty-two global specialists in AF and 13 industry partners met to develop innovative solutions based on new...

  14. APOLLO I: Anticoagulation control in atrial fibrillation.

    Science.gov (United States)

    Pinho-Costa, Luís; Moreira, Sónia; Azevedo, Cristiana; Azevedo, Pedro; Castro, Elisabete; Sousa, Hélder; Melo, Miguel

    2015-05-01

    Anticoagulation control as assessed by time in therapeutic range (TTR) correlates positively with the safety and efficacy of thromboprophylaxis in atrial fibrillation. We set out to assess TTR in our unit and to investigate determinants of better control. This was a case series study of atrial fibrillation patients anticoagulated with warfarin or acenocoumarol at the Family Health Unit of Fânzeres. Sociodemographic and clinical data were collected and TTR was calculated by the Rosendaal method, based on international normalized ratio tests performed in external laboratories in the preceding six months. SPSS 21.0 was used for the statistical analysis, with descriptive statistics, Spearman's correlation, and the Mann-Whitney U and Kruskal-Wallis tests. Of the 106 eligible patients, 70% participated in the study. Median TTR was 65.3% (P25=48.3%, P75=86.8%). We found a positive association between this variable and duration of atrial fibrillation (ρ=0.477, p0.05). Median TTR in our unit is similar to that in southern European countries and close to the good control threshold (70%) proposed by the European Society of Cardiology. The duration of atrial fibrillation and of anticoagulation explains only a small part of the measure's variability. Other determinants of anticoagulation control must be investigated in future studies and comparative studies should be carried out in family health units monitoring anticoagulation on the premises. Copyright © 2014 Sociedade Portuguesa de Cardiologia. Published by Elsevier España. All rights reserved.

  15. Aggregation and fibrillation of bovine serum albumin

    DEFF Research Database (Denmark)

    Holm, NK; Jespersen, SK; Thomassen, LV

    2007-01-01

    The all-alpha helix multi-domain protein bovine serum albumin (BSA) aggregates at elevated temperatures. Here we show that these thermal aggregates have amyloid properties. They bind the fibril-specific dyes Thioflavin T and Congo Red, show elongated although somewhat worm-like morphology...

  16. Exploiting oleuropein for inhibiting collagen fibril formation.

    Science.gov (United States)

    Bharathy, H; Fathima, N Nishad

    2017-08-01

    Collagen fibrils accumulate in excessive amounts and impair the normal functioning of the organ; therefore it stimulates the interest for identifying the compounds that could prevent the formation of fibrils. Herein, inhibition of self-assembly of collagen using oleuropein has been studied. The changes in the physico-chemical characteristics of collagen on interaction with increasing concentration of oleuropein has been studied using techniques like viscosity, UV-vis, CD and FT-IR. The inhibitory effect of oleuropein on fibril formation of collagen was proved using SEM. Circular dichroism and FT-IR spectra elucidates the alterations in the secondary structure of collagen suggesting non-covalent interactions between oleuropein and collagen. The decreased rate of collagen fibril formation also confirms the inhibition in the self-assembly of collagen. Hence, our study suggests that inhibition of the self-assembly process using oleuropein may unfold new avenues to treat fibrotic diseases. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. Spontaneous conversion of first onset atrial fibrillation

    DEFF Research Database (Denmark)

    Lindberg, Søren Østergaard; Hansen, Sidsel; Nielsen, Tonny

    2011-01-01

    Background  We studied all patients admitted to hospital with first onset atrial fibrillation (AF) to determine the probability of spontaneous conversion to sinus rhythm and to identify factors predictive of such a conversion. Methods and Results  We retrospectively reviewed charts of 438...

  18. Attitudes Towards Catheter Ablation for Atrial Fibrillation

    DEFF Research Database (Denmark)

    Vadmann, Henrik; Pedersen, Susanne S; Nielsen, Jens Cosedis

    2015-01-01

    BACKGROUND: Catheter ablation for atrial fibrillation (AF) is an important but expensive procedure that is the subject of some debate. Physicians´ attitudes towards catheter ablation may influence promotion and patient acceptance. This is the first study to examine the attitudes of Danish...

  19. An "account" of digitalis and atrial fibrillation

    NARCIS (Netherlands)

    Meijler, F.L.

    This review deals with the mechanisms by which digitalis exerts its "opium-Iike" action on the ventricular rate in patients with atrial fibrillation. To understand the effect of digitalis on ventricular rate and rhythm, it is essential to learn more about the basic electrophysiologic

  20. Atrial fibrillation, stroke, and quality of life.

    Science.gov (United States)

    Chinitz, Jason S; Castellano, Jose M; Kovacic, Jason C; Fuster, Valentin

    2012-04-01

    Contemporary management of atrial fibrillation imposes many challenges, particularly in the setting of our aging population. In addition to well-recognized consequences, such as stroke and mortality, emerging evidence relates atrial fibrillation to elevated risk of dementia, posing further therapeutic challenges. As the incidence of atrial fibrillation rises with age, the balance of controlling stroke risk and limiting major hemorrhage on anticoagulation has become increasingly critical in elderly patients. Appreciation of more extensive risk factors has made it possible to identify patients at very low risk of thromboembolism and higher risk of bleeding. However, practice guidelines in the United States and abroad have occasionally divergent viewpoints regarding how to best manage patients in various risk strata. Options for stroke prevention have expanded with novel antithrombotics and promising mechanical alternatives to anticoagulation, which may be at least as effective in preventing stroke without increasing bleeding risk. Catheter ablation has demonstrated impressive success at preventing atrial fibrillation recurrence in selected patients, and has the potential to further improve outcomes. In addition, the role of antiplatelet medications in patients deemed unsuitable for anticoagulation has been better clarified, although novel agents require further study to assess their impact on thromboembolism. High-bleeding risks associated with the concomitant use of multiple antithrombotics remains a major obstacle in patients with indications for both antiplatelet and anticoagulant therapy. © 2012 New York Academy of Sciences.

  1. Stress transmission in soil

    DEFF Research Database (Denmark)

    Lamandé, Mathieu; Schjønning, Per

    We urgently need increased quantitative knowledge on stress transmission in real soils loaded with agricultural machinery. 3D measurements of vertical stresses under tracked wheels were performed in situ in a Stagnic Luvisol (clay content 20 %) continuously cropped with small grain cereals......). Seven load cells were inserted horizontally from a pit with minimal disturbance of soil in each of three depths (0.3, 0.6 and 0.9 m), covering the width of the wheeled area. The position of the wheel relative to the transducers was recorded using a laser sensor. Finally, the vertical stresses near...... the soil-tyre interface were measured in separate tests by 17 stress transducers across the width of the tyres. The results showed that the inflation pressure controlled the level of maximum stresses at 0.3 m depth, while the wheel load was correlated to the measured stresses at 0.9 m depth. This supports...

  2. Effects of maturation and advanced glycation on tensile mechanics of collagen fibrils from rat tail and Achilles tendons.

    Science.gov (United States)

    Svensson, Rene B; Smith, Stuart T; Moyer, Patrick J; Magnusson, S Peter

    2018-02-13

    Connective tissues are ubiquitous throughout the body and consequently affect the function of many organs. In load bearing connective tissues like tendon, the mechanical functionality is provided almost exclusively by collagen fibrils that in turn are stabilized by covalent cross-links. Functionally distinct tendons display different cross-link patterns, which also change with maturation, but these differences have not been studied in detail at the fibril level. In the present study, a custom built nanomechanical test platform was designed and fabricated to measure tensile mechanics of individual fibrils from rat tendons. The influence of animal maturity (4 vs. 16 week old rats) and functionally different tendons (tail vs. Achilles tendons) were examined. Additionally the effect of methylglyoxal (MG) treatment in vitro to form advanced glycation end products (AGEs) was investigated. Age and tissue type had no significant effect on fibril mechanics, but MG treatment increased strength and stiffness without inducing brittleness and gave rise to a distinct three-phase mechanical response corroborating that previously reported in human patellar tendon fibrils. That age and tissue had little mechanical effect, tentatively suggest that variations in enzymatic cross-links may play a minor role after initial tissue formation. Tendons are connective tissues that connect muscle to bone and carry some of the greatest mechanical loads in the body, which makes them common sites of injury. A tendon is essentially a biological rope formed by thin strands called fibrils made of the protein collagen. Tendon function relies on the strength of these fibrils, which in turn depends on naturally occurring cross-links between collagen molecules, but the mechanical influence of these cross-links have not been measured before. It is believed that beneficial cross-linking occurs with maturation while additional cross-linking with aging may lead to brittleness, but this study provides

  3. Amyloid Structure and Assembly: Insights from Scanning Transmission Electron Microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Goldsbury, C.; Wall, J.; Baxa, U.; Simon, M. N.; Steven, A. C.; Engel, A.; Aebi, U.; Muller, S. A.

    2011-01-01

    Amyloid fibrils are filamentous protein aggregates implicated in several common diseases such as Alzheimer's disease and type II diabetes. Similar structures are also the molecular principle of the infectious spongiform encephalopathies such as Creutzfeldt-Jakob disease in humans, scrapie in sheep, and of the so-called yeast prions, inherited non-chromosomal elements found in yeast and fungi. Scanning transmission electron microscopy (STEM) is often used to delineate the assembly mechanism and structural properties of amyloid aggregates. In this review we consider specifically contributions and limitations of STEM for the investigation of amyloid assembly pathways, fibril polymorphisms and structural models of amyloid fibrils. This type of microscopy provides the only method to directly measure the mass-per-length (MPL) of individual filaments. Made on both in vitro assembled and ex vivo samples, STEM mass measurements have illuminated the hierarchical relationships between amyloid fibrils and revealed that polymorphic fibrils and various globular oligomers can assemble simultaneously from a single polypeptide. The MPLs also impose strong constraints on possible packing schemes, assisting in molecular model building when combined with high-resolution methods like solid-state nuclear magnetic resonance (NMR) and electron paramagnetic resonance (EPR).

  4. Kinetically controlled thermal response of beta2-microglobulin amyloid fibrils.

    Science.gov (United States)

    Sasahara, Kenji; Naiki, Hironobu; Goto, Yuji

    2005-09-23

    Calorimetric measurements were carried out using a differential scanning calorimeter in the temperature range from 10 to 120 degrees C for characterizing the thermal response of beta2-microglobulin amyloid fibrils. The thermograms of amyloid fibril solution showed a remarkably large decrease in heat capacity that was essentially released upon the thermal unfolding of the fibrils, in which the magnitude of negative heat capacity change was not explicable in terms of the current accessible surface area model of protein structural thermodynamics. The heat capacity-temperature curve of amyloid fibrils prior to the fibril unfolding exhibited an unusual dependence on the fibril concentration and the heating rate. Particularly, the heat needed to induce the thermal response was found to be linearly dependent on the heating rate, indicating that its thermal response is under a kinetic control and precluding the interpretation in terms of equilibrium thermodynamics. Furthermore, amyloid fibrils of amyloid beta peptides also exhibited a heating rate-dependent exothermic process before the fibril unfolding, indicating that the kinetically controlled thermal response may be a common phenomenon to amyloid fibrils. We suggest that the heating rate-dependent negative change in heat capacity is coupled to the association of amyloid fibrils with characteristic hydration pattern.

  5. Data transmission

    National Research Council Canada - National Science Library

    Tugal, Dogan A; Tugal, Osman

    1989-01-01

    This updated second edition provides working answers to today's critical questions about designing and managing all types of data transmission systems and features a new chapter on local area networks (LANs...

  6. Shingles Transmission

    Science.gov (United States)

    ... Search Form Controls Cancel Submit Search The CDC Shingles (Herpes Zoster) Note: Javascript is disabled or is ... message, please visit this page: About CDC.gov . Shingles Home About Shingles Overview Signs & Symptoms Transmission Complications ...

  7. Tendon Force Transmission at the Nanoscale

    DEFF Research Database (Denmark)

    Svensson, René

    2013-01-01

    The subject of this study is connective tissues, in particular tendon. Connective tissues consist of an extracellular matrix made of the protein collagen, which is responsible for the mechanical integrity of the body. While connective tissues may appear simple, there are still many aspects...... of connective tissue function that are poorly understood. One such aspect is the microscopic mechanisms of force transmission through tendons over macroscopic distances. Force transmission is at the heart of tendon function, but the large range of scales in the hierarchical structure of tendons has made...... it difficult to tackle. The tendon hierarchy ranges from molecules (2 nm) over fibrils (200 nm), fibers (2 μm) and fascicles (200 μm) to tendons (10 mm), and to derive the mechanisms of force transmission it is necessary to know the mechanical behavior at each hierarchical level. The aim of the present work...

  8. Molecular and Biological Compatibility with Host Alpha-Synuclein Influences Fibril Pathogenicity

    Directory of Open Access Journals (Sweden)

    Kelvin C. Luk

    2016-09-01

    Full Text Available The accumulation and propagation of misfolded α-synuclein (α-Syn is a central feature of Parkinson’s disease and other synucleinopathies. Molecular compatibility between a fibrillar seed and its native protein state is a major determinant of amyloid self-replication. We show that cross-seeded aggregation of human (Hu and mouse (Ms α-Syn is bidirectionally restricted. Although fibrils formed by Hu-Ms-α-Syn chimeric mutants can overcome this inhibition in cell-free systems, sequence homology poorly predicts their efficiency in inducing α-Syn pathology in primary neurons or after intracerebral injection into wild-type mice. Chimeric α-Syn fibrils demonstrate enhanced or reduced pathogenicities compared with wild-type Hu- or Ms-α-Syn fibrils. Furthermore, α-Syn mutants induced to polymerize by fibrillar seeds inherit the functional properties of their template, suggesting that transferable pathogenic and non-pathogenic states likely influence the initial engagement between exogenous α-Syn seeds and endogenous neuronal α-Syn. Thus, transmission of synucleinopathies is regulated by biological processes in addition to molecular compatibility.

  9. Investigating the effects of erythrosine B on amyloid fibril formation derived from lysozyme.

    Science.gov (United States)

    Kuo, Chun-Tien; Chen, Yi-Lin; Hsu, Wei-Tse; How, Su-Chun; Cheng, Yu-Hong; Hsueh, Shu-Shun; Liu, Hwai-Shen; Lin, Ta-Hsien; Wu, Josephine W; Wang, Steven S-S

    2017-05-01

    Formation of amyloid fibrils has been associated with at least 30 different protein aggregation diseases. The 129-residue polypeptide hen lysozyme, which is structurally homologous to human lysozyme, has been demonstrated to exhibit amyloid fibril-forming propensity in vitro. This study is aimed at exploring the influence of erythrosine B on the in vitro amyloid fibril formation of hen lysozyme at pH 2.0 and 55°C using ThT binding assay, transmission electron microscopy, far-UV circular dichroism absorption spectroscopy, 1-anilinonaphthalene-8-sulfonic acid fluorescence spectroscopy, and synchronous fluorescence study. We found that lysozyme fibrillogenesis was dose-dependently suppressed by erythrosine B. In addition, our far-UV CD and ANS fluorescence data showed that, as compared with the untreated lysozyme control, the α-to-ß transition and exposure of hydrophobic clusters in lysozyme were reduced upon treatment with erythrosine B. Moreover, it could be inferred that the binding of erythrosine B occurred in the vicinity of the tryptophan residues. Finally, molecular docking and molecular dynamics simulations were further employed to gain some insights into the possible binding site(s) and interactions between lysozyme and erythrosine B. We believe the results obtained here may contribute to the development of potential strategies/approaches for the suppression of amyloid fibrillogenesis, which is implicated in amyloid pathology. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. SDS-Induced Fibrillation of α-Synuclein

    DEFF Research Database (Denmark)

    Giehm, L.; Oliveira, Cristiano Luis Pinto De; Pedersen, J.S.

    2010-01-01

    A structural investigation of the sodium dodecyl sulfate (SDS)-induced fibrillation of α-synuclein (αSN), a 140-amino-acid protein implicated in Parkinson's disease, has been performed. Spectroscopic analysis has been combined with isothermal titration calorimetry, small-angle X-ray scattering...... of SDS. The SDS-induced fibrils have a flexible worm-like appearance, which can be converted into classical straight fibrils by continuous agitation. SDS-induced fibrillation represents an alternative and highly reproducible mechanism for fibrillation where protein association is driven by the formation...... of shared micelles, which subsequently allows the formation of β-sheet structures that presumably link individual micelles. This illustrates that protein fibrillation may occur by remarkably different mechanisms, testifying to the versatility of this process....

  11. Hydrogen-Deuterium Exchange Profiles of Polyubiquitin Fibrils

    Directory of Open Access Journals (Sweden)

    Daichi Morimoto

    2018-02-01

    Full Text Available Ubiquitin and its polymeric forms are conjugated to intracellular proteins to regulate diverse intracellular processes. Intriguingly, polyubiquitin has also been identified as a component of pathological protein aggregates associated with Alzheimer’s disease and other neurodegenerative disorders. We recently found that polyubiquitin can form amyloid-like fibrils, and that these fibrillar aggregates can be degraded by macroautophagy. Although the structural properties appear to function in recognition of the fibrils, no structural information on polyubiquitin fibrils has been reported so far. Here, we identify the core of M1-linked diubiquitin fibrils from hydrogen-deuterium exchange experiments using solution nuclear magnetic resonance (NMR spectroscopy. Intriguingly, intrinsically flexible regions became highly solvent-protected in the fibril structure. These results indicate that polyubiquitin fibrils are formed by inter-molecular interactions between relatively flexible structural components, including the loops and edges of secondary structure elements.

  12. Evidence of structurally continuous collagen fibrils in tendon

    DEFF Research Database (Denmark)

    Svensson, Rene B; Herchenhan, Andreas; Starborg, Tobias

    2017-01-01

    favor continuity. This study initially set out to trace the full length of individual fibrils in adult human tendons, using serial block face-scanning electron microscopy. But even with this advanced technique the required length could not be covered. Instead a statistical approach was used on a large...... volume of fibrils in shorter image stacks. Only a single end was observed after tracking 67.5 mm of combined fibril lengths, in support of fibril continuity. To shed more light on this observation, the full length of a short tendon (mouse stapedius, 125 μm) was investigated and continuity of individual...... fibrils was confirmed. In light of these results, possible mechanisms that could reconcile the opposing findings on fibril continuity are discussed. STATEMENT OF SIGNIFICANCE: Connective tissues hold all parts of the body together and are mostly constructed from thin threads of the protein collagen...

  13. Red Wine, Resveratrol and Atrial Fibrillation

    OpenAIRE

    Stephan, Laura Siga; Almeida, Eduardo Dytz; Markoski, Melissa Medeiros; Garavaglia, Juliano; Marcadenti, Aline

    2017-01-01

    Atrial fibrillation (AF) is a common cardiac arrhythmia that is associated with increased risk for cardiovascular disease and overall mortality. Excessive alcohol intake is a well-known risk factor for AF, but this correlation is less clear with light and moderate drinking. Besides, low doses of red wine may acutely prolong repolarization and slow cardiac conduction. Resveratrol, a bioactive polyphenol found in grapes and red wine, has been linked to antiarrhythmic properties and may act as a...

  14. [Ventricular fibrillation following deodorant spray inhalation].

    Science.gov (United States)

    Girard, F; Le Tacon, S; Maria, M; Pierrard, O; Monin, P

    2008-01-01

    We report one case of out-of-hospital cardiac arrest with ventricular fibrillation following butane poisoning after inhalation of antiperspiration aerosol. An early management using semi-automatic defibrillator explained the success of the resuscitation. The mechanism of butane toxicity could be an increased sensitivity of cardiac receptors to circulating catecholamines, responsible for cardiac arrest during exercise and for resuscitation difficulties. The indication of epinephrine is discussed.

  15. Acute atrial fibrillation during dengue hemorrhagic fever

    Directory of Open Access Journals (Sweden)

    Veloso Henrique Horta

    2003-01-01

    Full Text Available Dengue fever is a viral infection transmitted by the mosquito, Aedes aegypti. Cardiac rhythm disorders, such as atrioventricular blocks and ventricular ectopic beats, appear during infection and are attributed to viral myocarditis. However, supraventricular arrhythmias have not been reported. We present a case of acute atrial fibrillation, with a rapid ventricular rate, successfully treated with intravenous amiodarone, in a 62-year-old man with dengue hemorrhagic fever, who had no structural heart disease.

  16. Exercise-based cardiac rehabilitation for adults with atrial fibrillation

    OpenAIRE

    Risom, Signe Stelling; Zwisler, Ann-Dorthe; Johansen, Pernille Palm; Sibilitz, Kirstine Lærum; Lindschou, Jane; Gluud, Christian; Taylor, Rod S; Svendsen, Jesper H; Kikkenborg Berg, Selina

    2017-01-01

    BACKGROUND: Exercise-based cardiac rehabilitation may benefit adults with atrial fibrillation or those who had been treated for atrial fibrillation. Atrial fibrillation is caused by multiple micro re-entry circuits within the atrial tissue, which result in chaotic rapid activity in the atria.OBJECTIVES: To assess the benefits and harms of exercise-based rehabilitation programmes, alone or with another intervention, compared with no-exercise training controls in adults who currently have AF, o...

  17. Étude pathophysiologique de la fibrillation atriale : approche multifacette

    OpenAIRE

    Morel, Élodie

    2010-01-01

    Atrial fibrillation (AF) is the most common arrhythmia encountered in clinical practice. As its pathophysiology is still poorly understood, it is difficult to treat. Several parameters have been described as involved in the initiation of atrial fibrillation, but the precise mechanisms of initiation of atrial fibrillation are not understood. In this study, histological, biochemical, genetic and transcriptomic approaches have been performed in order to identify the substrates involved in the in...

  18. Transmission System Performance Analysis for High-Penetration Photovoltaics

    Energy Technology Data Exchange (ETDEWEB)

    Achilles, S.; Schramm, S.; Bebic, J.

    2008-02-01

    This study is an assessment of the potential impact of high levels of penetration of photovoltaic (PV) generation on transmission systems. The effort used stability simulations of a transmission system with different levels of PV generation and load.

  19. Electromechanical vortex filaments during cardiac fibrillation

    Science.gov (United States)

    Christoph, J.; Chebbok, M.; Richter, C.; Schröder-Schetelig, J.; Bittihn, P.; Stein, S.; Uzelac, I.; Fenton, F. H.; Hasenfuß, G.; Gilmour, R. F., Jr.; Luther, S.

    2018-03-01

    The self-organized dynamics of vortex-like rotating waves, which are also known as scroll waves, are the basis of the formation of complex spatiotemporal patterns in many excitable chemical and biological systems. In the heart, filament-like phase singularities that are associated with three-dimensional scroll waves are considered to be the organizing centres of life-threatening cardiac arrhythmias. The mechanisms that underlie the onset, maintenance and control of electromechanical turbulence in the heart are inherently three-dimensional phenomena. However, it has not previously been possible to visualize the three-dimensional spatiotemporal dynamics of scroll waves inside cardiac tissues. Here we show that three-dimensional mechanical scroll waves and filament-like phase singularities can be observed deep inside the contracting heart wall using high-resolution four-dimensional ultrasound-based strain imaging. We found that mechanical phase singularities co-exist with electrical phase singularities during cardiac fibrillation. We investigated the dynamics of electrical and mechanical phase singularities by simultaneously measuring the membrane potential, intracellular calcium concentration and mechanical contractions of the heart. We show that cardiac fibrillation can be characterized using the three-dimensional spatiotemporal dynamics of mechanical phase singularities, which arise inside the fibrillating contracting ventricular wall. We demonstrate that electrical and mechanical phase singularities show complex interactions and we characterize their dynamics in terms of trajectories, topological charge and lifetime. We anticipate that our findings will provide novel perspectives for non-invasive diagnostic imaging and therapeutic applications.

  20. Glassy state of native collagen fibril?

    Science.gov (United States)

    Gevorkian, S. G.; Allahverdyan, A. E.; Gevorgyan, D. S.; Hu, C.-K.

    2011-07-01

    Our micromechanical experiments show that viscoelastic features of type-I collagen fibril at physiological temperatures display essential dependence on the frequency and speed of heating. For temperatures of 20-30 °C the internal friction has a sharp maximum for a frequency less than 2 kHz. Upon heating the internal friction displays a peak at a temperature Tsoft(v) that essentially depends on the speed of heating v: Tsoft≈70°C for v=1°C/min, and Tsoft≈25°C for v=0.1°C/min. At the same temperature Tsoft(v) Young's modulus passes through a minimum. All these effects are specific for the native state of the fibril and disappear after heat-denaturation. Taken together with the known facts that the fibril is axially ordered as quasicrystal, but disordered laterally, we interpret our findings as indications of a glassy state, where Tsoft is the softening transition.

  1. Atrial Fibrillation in Eight New World Camelids.

    Science.gov (United States)

    Bozorgmanesh, R; Magdesian, K G; Estell, K E; Stern, J A; Swain, E A; Griffiths, L G

    2016-01-01

    There is limited information on the incidence of clinical signs, concurrent illness and treatment options for atrial fibrillation (AF) in New World Camelids (NWC). Describe clinical signs and outcome of AF in NWC. Eight New World Camelids admitted with AF. A retrospective observational study of camelids diagnosed with AF based on characteristic findings on electrocardiogram (ECG). All animals had an irregularly irregular heart rhythm detected on physical examination and 4 cases had obtunded mentation on admission. Three camelids were diagnosed with AF secondary to oleander intoxication, 3 animals had underlying cardiovascular disease, 1 was diagnosed with lone AF and 1 had AF diagnosed on examination for a urethral obstruction. Five of eight animals survived to discharge and nonsurvivors consisted of animals which died or were euthanized as a result of cardiovascular disease (2/8) or extra-cardiac disease unrelated to the AF (1/8). Atrial fibrillation occurs in NWC in association with cardiovascular disease, extra-cardiac disease or as lone AF. Amiodarone and transthoracic cardioversion were attempted in one llama with lone AF, but were unsuccessful. Atrial fibrillation was recorded in 0.1% of admissions. Copyright © 2015 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals, Inc. on behalf of the American College of Veterinary Internal Medicine.

  2. Effect on transmission of HIV-1 resistance of timing of implementation of viral load monitoring to determine switches from first to second-line antiretroviral regimens in resource-limited settings

    DEFF Research Database (Denmark)

    Phillips, Andrew N; Pillay, Deenan; Garnett, Geoff

    2011-01-01

    There is concern that antiretroviral therapy (ART) use with only clinical monitoring for failure will result in high rates of transmission of virus with resistance to drugs currently in use.......There is concern that antiretroviral therapy (ART) use with only clinical monitoring for failure will result in high rates of transmission of virus with resistance to drugs currently in use....

  3. Mechanical properties of a collagen fibril under simulated degradation.

    Science.gov (United States)

    Malaspina, David C; Szleifer, Igal; Dhaher, Yasin

    2017-11-01

    Collagen fibrils are a very important component in most of the connective tissue in humans. An important process associated with several physiological and pathological states is the degradation of collagen. Collagen degradation is usually mediated by enzymatic and non-enzymatic processes. In this work we use molecular dynamics simulations to study the influence of simulated degradation on the mechanical properties of the collagen fibril. We applied tensile stress to the collagen fiber at different stages of degradation. We compared the difference in the fibril mechanical priorities due the removal of enzymatic crosslink, surface degradation and volumetric degradation. As anticipated, our results indicated that, regardless of the degradation scenario, fibril mechanical properties is reduced. The type of degradation mechanism (crosslink, surface or volumetric) expressed differential effect on the change in the fibril stiffness. Our simulation results showed dramatic change in the fibril stiffness with a small amount of degradation. This suggests that the hierarchical structure of the fibril is a key component for the toughness and is very sensitive to changes in the organization of the fibril. The overall results are intended to provide a theoretical framework for the understanding the mechanical behavior of collagen fibrils under degradation. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Toxic species in amyloid disorders: Oligomers or mature fibrils

    Directory of Open Access Journals (Sweden)

    Meenakshi Verma

    2015-01-01

    Full Text Available Protein aggregation is the hallmark of several neurodegenerative disorders. These protein aggregation (fibrillization disorders are also known as amyloid disorders. The mechanism of protein aggregation involves conformation switch of the native protein, oligomer formation leading to protofibrils and finally mature fibrils. Mature fibrils have long been considered as the cause of disease pathogenesis; however, recent evidences suggest oligomeric intermediates formed during fibrillization to be toxic. In this review, we have tried to address the ongoing debate for these toxic amyloid species. We did an extensive literature search and collated information from Pubmed (http://www.ncbi.nlm.nih.gov and Google search using various permutations and combinations of the following keywords: Neurodegeneration, amyloid disorders, protein aggregation, fibrils, oligomers, toxicity, Alzheimer′s Disease, Parkinson′s Disease. We describe different instances showing the toxicity of mature fibrils as well as oligomers in Alzheimer′s Disease and Parkinson′s Disease. Distinct structural framework and morphology of amyloid oligomers suggests difference in toxic effect between oligomers and fibrils. We highlight the difference in structure and proposed toxicity pathways for fibrils and oligomers. We also highlight the evidences indicating that intermediary oligomeric species can act as potential diagnostic biomarker. Since the formation of these toxic species follow a common structural switch among various amyloid disorders, the protein aggregation events can be targeted for developing broad-range therapeutics. The therapeutic trials based on the understanding of different protein conformers (monomers, oligomers, protofibrils and fibrils in amyloid cascade are also described.

  5. Load Measurements

    DEFF Research Database (Denmark)

    Kock, Carsten Weber; Vesth, Allan

    The report describes Load measurements carried out on a given wind turbine. The aim of the measurement program regarding the loads on the turbine is to verify the basic characteristics of the wind turbine and loads on the blades, the rotor and the tower, using [Ref 1], [Ref2] and [Ref 3]. Regarding...... the fatigue loads, the rotor, blades and tower moments are presented. The fatigue loads are evaluated using rainflow counting described in detail in Ref. [1]. The 1Hz equivalent load ranges are calculated at different wind speeds. All information regarding the instrumentation is collected in [ref 4] and [ref...

  6. Regional transmission subsystem planning

    Energy Technology Data Exchange (ETDEWEB)

    Costa Bortoni, Edson da [Quadrante Softwares Especializados Ltda., Itajuba, MG (Brazil); Bajay, Sergio Valdir; Barros Correia, Paulo de [Universidade Estadual de Campinas, SP (Brazil). Faculdade de Engenharia Mecanica; Santos, Afonso Henriques Moreira; Haddad, Jamil [Escola Federal de Engenharia de Itajuba, MG (Brazil)

    1994-12-31

    This work presents an approach for the planning of transmission systems by employing mixed--integer linear programming to obtain a cost and operating characteristics optimized system. The voltage loop equations are written in a modified form, so that, at the end of the analysis, the model behaves as a DC power flow, with the help of the two Kirchhoff`s laws, exempting the need of interaction with an external power flow program for analysis of the line loading. The model considers the occurrence of contingencies, so that the final result is a network robust to the most severe contingencies. This whole technique is adapted to the regional electric power transmission subsystems. (author) 9 refs., 4 figs.

  7. HIV Transmission

    Science.gov (United States)

    ... Abroad Treatment Basic Statistics Get Tested Find an HIV testing site near you. Enter ZIP code or city Follow HIV/AIDS CDC HIV CDC HIV/AIDS See RSS | ... on HIV Syndicated Content Website Feedback HIV/AIDS HIV Transmission Language: English (US) Español (Spanish) Recommend on ...

  8. Structural origin of polymorphism of Alzheimer's amyloid β-fibrils.

    Science.gov (United States)

    Agopian, Audrey; Guo, Zhefeng

    2012-10-01

    Formation of senile plaques containing amyloid fibrils of Aβ (amyloid β-peptide) is a pathological hallmark of Alzheimer's disease. Unlike globular proteins, which fold into unique structures, the fibrils of Aβ and other amyloid proteins often contain multiple polymorphs. Polymorphism of amyloid fibrils leads to different toxicity in amyloid diseases and may be the basis for prion strains, but the structural origin for fibril polymorphism is still elusive. In the present study we investigate the structural origin of two major fibril polymorphs of Aβ40: an untwisted polymorph formed under agitated conditions and a twisted polymorph formed under quiescent conditions. Using electron paramagnetic resonance spectroscopy, we studied the inter-strand side-chain interactions at 14 spin-labelled positions in the Aβ40 sequence. The results of the present study show that the agitated fibrils have stronger inter-strand spin-spin interactions at most of the residue positions investigated. The two hydrophobic regions at residues 17-20 and 31-36 have the strongest interactions in agitated fibrils. Distance estimates on the basis of the spin exchange frequencies suggest that inter-strand distances at residues 17, 20, 32, 34 and 36 in agitated fibrils are approximately 0.2 Å (1 Å=0.1 nm) closer than in quiescent fibrils. We propose that the strength of inter-strand side-chain interactions determines the degree of β-sheet twist, which then leads to the different association patterns between different cross β-units and thus distinct fibril morphologies. Therefore the inter-strand side-chain interaction may be a structural origin for fibril polymorphism in Aβ and other amyloid proteins.

  9. Graphene-supporting films and low-voltage STEM in SEM toward imaging nanobio materials without staining: Observation of insulin amyloid fibrils.

    Science.gov (United States)

    Ogawa, Takashi; Gang, Geun Won; Thieu, Minh Thu; Kwon, Hyuksang; Ahn, Sang Jung; Ha, Tai Hwan; Cho, Boklae

    2017-05-01

    Utilization of graphene-supporting films and low-voltage scanning transmission electron microscopy (LV-STEM) in scanning electron microscopy (SEM) is shown to be an effective means of observing unstained nanobio materials. Insulin amyloid fibrils, which are implicated as a cause of type II diabetes, are formed in vitro and observed without staining at room temperature. An in-lens cold field-emission SEM, equipped with an additional homemade STEM detector, provides dark field (DF)-STEM images in the low energy range of 5-30keV, together with secondary electron (SE) images. Analysis based on Lenz's theory is used to interpret the experimental results. Graphene films, where the fibrils are deposited, reduce the background level of the STEM images compared with instances when conventional amorphous carbon films are used. Using 30keV, which is lower than that for conventional TEM (100-300keV), together with low detection angles (15-55mrad) enhances the signals from the fibrils. These factors improve image quality, which enables observation of thin fibrils with widths of 7-8nm. STEM imaging clearly reveals a twisted-ribbon structure of a fibril, and SE imaging shows an emphasized striped pattern of the fibril. The LV-STEM in SEM enables acquisition of two types of images of an identical fibril in a single instrument, which is useful for understanding the structure. This study expands the application of SEM to other systems of interest, which is beneficial to a large number of users. The method in this study can be applied to the observation of various nanobio materials and analysis of their native structures, thus contributing to research in materials and life sciences. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Does Myocardial Infarction Beget Atrial Fibrillation and Atrial Fibrillation Beget Myocardial Infarction?

    NARCIS (Netherlands)

    Vermond, Rob A.; Van Gelder, Isabelle C.; Crijns, Harry J.; Rienstra, Michiel

    2015-01-01

    Atrial fibrillation (AF) affects millions of people worldwide.(1) It is already known several decades that AF is not a benign condition, and it's associated with a 5-fold increased risk of stroke, 3-fold increased risk of heart failure, and doubling of risk of dementia and death.(2-4) Myocardial

  11. Light Chain Amyloid Fibrils Cause Metabolic Dysfunction in Human Cardiomyocytes.

    Directory of Open Access Journals (Sweden)

    Helen P McWilliams-Koeppen

    Full Text Available Light chain (AL amyloidosis is the most common form of systemic amyloid disease, and cardiomyopathy is a dire consequence, resulting in an extremely poor prognosis. AL is characterized by the production of monoclonal free light chains that deposit as amyloid fibrils principally in the heart, liver, and kidneys causing organ dysfunction. We have studied the effects of amyloid fibrils, produced from recombinant λ6 light chain variable domains, on metabolic activity of human cardiomyocytes. The data indicate that fibrils at 0.1 μM, but not monomer, significantly decrease the enzymatic activity of cellular NAD(PH-dependent oxidoreductase, without causing significant cell death. The presence of amyloid fibrils did not affect ATP levels; however, oxygen consumption was increased and reactive oxygen species were detected. Confocal fluorescence microscopy showed that fibrils bound to and remained at the cell surface with little fibril internalization. These data indicate that AL amyloid fibrils severely impair cardiomyocyte metabolism in a dose dependent manner. These data suggest that effective therapeutic intervention for these patients should include methods for removing potentially toxic amyloid fibrils.

  12. Atrial fibrillation in an adolescent--the agony of ecstasy.

    Science.gov (United States)

    Madhok, Ashish; Boxer, Robert; Chowdhury, Devyani

    2003-10-01

    Ecstasy (MDMA), a popular drug of abuse among teenagers, is thought to be "relatively" safe. A case of atrial fibrillation following the ingestion of ecstasy in a previously well adolescent is presented. Emergency room physicians should consider ecstasy abuse in the differential diagnosis of young patients presenting with atrial fibrillation.

  13. Atrial fibrillation and bleeding complication - risk factors and risk marker

    NARCIS (Netherlands)

    Breithardt, G.; Ravens, U.; Kirchhof, P.; van Gelder, I. C.

    2012-01-01

    The development of atrial fibrillation (AF) is closely linked to risk factors like hypertension and heart failure, diabetes mellitus, myocardial infarction and valvular heart disease. These factors partly overlap with those which determine the progression of atrial fibrillation and the incidence of

  14. Radiofrequency ablation as initial therapy in paroxysmal atrial fibrillation

    DEFF Research Database (Denmark)

    Cosedis Nielsen, Jens; Johannessen, Arne; Raatikainen, Pekka

    2012-01-01

    There are limited data comparing radiofrequency catheter ablation with antiarrhythmic drug therapy as first-line treatment in patients with paroxysmal atrial fibrillation.......There are limited data comparing radiofrequency catheter ablation with antiarrhythmic drug therapy as first-line treatment in patients with paroxysmal atrial fibrillation....

  15. Effect of dronedarone on cardiovascular events in atrial fibrillation

    DEFF Research Database (Denmark)

    Hohnloser, Stefan H; Crijns, Harry J G M; van Eickels, Martin

    2009-01-01

    BACKGROUND: Dronedarone is a new antiarrhythmic drug that is being developed for the treatment of patients with atrial fibrillation. METHODS: We conducted a multicenter trial to evaluate the use of dronedarone in 4628 patients with atrial fibrillation who had additional risk factors for death...

  16. Dronedarone in high-risk permanent atrial fibrillation

    DEFF Research Database (Denmark)

    Connolly, Stuart J; Camm, A John; Halperin, Jonathan L

    2011-01-01

    Dronedarone restores sinus rhythm and reduces hospitalization or death in intermittent atrial fibrillation. It also lowers heart rate and blood pressure and has antiadrenergic and potential ventricular antiarrhythmic effects. We hypothesized that dronedarone would reduce major vascular events...... in high-risk permanent atrial fibrillation....

  17. Continuing Education: Atrial fibrillation: Current trends in management

    African Journals Online (AJOL)

    There is however, a recent resurgence of interest following some important experimental and therapeutic advances. This article reviews the current understanding of the nature of atrial fibrillation (AF) and some recent developments in the pharmacological and alternative therapeutic approaches. Key Words: Atrial fibrillation, ...

  18. PMEL Amyloid Fibril Formation: The Bright Steps of Pigmentation

    Directory of Open Access Journals (Sweden)

    Christin Bissig

    2016-08-01

    Full Text Available In pigment cells, melanin synthesis takes place in specialized organelles, called melanosomes. The biogenesis and maturation of melanosomes is initiated by an unpigmented step that takes place prior to the initiation of melanin synthesis and leads to the formation of luminal fibrils deriving from the pigment cell-specific pre-melanosomal protein (PMEL. In the lumen of melanosomes, PMEL fibrils optimize sequestration and condensation of the pigment melanin. Interestingly, PMEL fibrils have been described to adopt a typical amyloid-like structure. In contrast to pathological amyloids often associated with neurodegenerative diseases, PMEL fibrils represent an emergent category of physiological amyloids due to their beneficial cellular functions. The formation of PMEL fibrils within melanosomes is tightly regulated by diverse mechanisms, such as PMEL traffic, cleavage and sorting. These mechanisms revealed increasing analogies between the formation of physiological PMEL fibrils and pathological amyloid fibrils. In this review we summarize the known mechanisms of PMEL fibrillation and discuss how the recent understanding of physiological PMEL amyloid formation may help to shed light on processes involved in pathological amyloid formation.

  19. La fibrillation auriculaire chez le noir Africain: Aspects ...

    African Journals Online (AJOL)

    In this retrospective work realized during two years (1st january 2002 to 31 december 2003), relative to 300 cases hospitalized at the Cardiology Institute of Abidjan, the authors have studied the epidemiologic, etiologic and prognosis factors of black african atrial fibrillation in hospital cercle. The atrial fibrillation was the most ...

  20. Relevance of Electrical Remodeling in Human Atrial Fibrillation Results of the Asymptomatic Atrial Fibrillation and Stroke Evaluation in Pacemaker Patients and the Atrial Fibrillation Reduction Atrial Pacing Trial Mechanisms of Atrial Fibrillation Study

    NARCIS (Netherlands)

    Healey, Jeff S.; Israel, Carsten W.; Connolly, Stuart J.; Hohnloser, Stefan H.; Nair, Girish M.; Divakaramenon, Syamkumar; Capucci, Alessandro; Van Gelder, Isabelle C.; Lau, Chu-Pak; Gold, Michael R.; Carlson, Mark; Themeles, Ellison; Morillo, Carlos A.

    Background-In animal models of atrial fibrillation (AF), changes in atrial electrophysiological properties are associated with the development of AF. Their relevance to human AF is unclear. Methods and Results-The Asymptomatic Atrial Fibrillation and Stroke Evaluation in Pacemaker Patients and the

  1. The immediate future for the medical treatment of atrial fibrillation

    DEFF Research Database (Denmark)

    Pedersen, Ole Dyg; Brendorp, Bente; Køber, Lars

    2002-01-01

    Atrial fibrillation is the most commonly sustained cardiac arrhythmia and a common reason for mortality and morbidity. Atrial fibrillation causes disease for three reasons: i) the ventricular rate is often high, which leads to symptoms ranging from discomfort to life threatening heart failure; ii...

  2. Vascular disease and stroke risk in atrial fibrillation

    DEFF Research Database (Denmark)

    Olesen, Jonas Bjerring; Lip, Gregory Y.H.; Lane, Deirdre A

    2012-01-01

    Vascular disease (including myocardial infarction and peripheral artery disease) has been proposed as a less well-validated risk factor for stroke in patients with atrial fibrillation. We investigated whether vascular disease is an independent risk factor of stroke/thromboembolism in atrial...... fibrillation and whether adding vascular disease improves Congestive heart failure, Hypertension, Age 75 years, Diabetes, previous Stroke (CHADS(2)) risk stratification....

  3. Electrothermal Coordination in Cable Based Transmission Grids

    DEFF Research Database (Denmark)

    Olsen, Rasmus Schmidt; Holbøll, Joachim; Gudmundsdottir, Unnur Stella

    2013-01-01

    Electrothermal coordination (ETC) is introduced for cable based transmission grids. ETC is the term covering operation and planning of transmission systems based on temperature, instead of current. ETC consists of one part covering the load conditions of the system and one covering the thermal be...

  4. Transmission Line Series Compensation for Wind Energy Transmission

    International Nuclear Information System (INIS)

    Palanichamy, C; Wong, Y C

    2015-01-01

    Wind energy has demonstrated to be a clean, copious and absolutely renewable source of energy, and the large penetration of it into the power grid indicates that wind energy is considered an effective means of power generation, Transmission of wind energy from remote locations to load centers necessitates long transmission lines. Series compensation is a proven and economical transmission solution to address system power transfer strength, grid stability, and voltage profile issues of long transmission lines. In this paper, a programmable approach to determine the capacitive reactance of series capacitor and optimum location for its placement to achieve maximum power transfer gas been presented. The respective program with sample solutions has been provided for real-time applications. (paper)

  5. The Inhibitory Effect of Natural Products on Protein Fibrillation May Be Caused by Degradation Products--A Study Using Aloin and Insulin.

    Directory of Open Access Journals (Sweden)

    Eva S Lobbens

    Full Text Available Protein fibrillation is the pathological hallmark of several neurodegenerative diseases and also complicates the manufacturing and use of protein drugs. As a case study, the inhibitory activity of the natural compound aloin against insulin fibrillation was investigated. Based on Thioflavin T assays, high-performance liquid chromatography and transmission electron microscopy it was found that a degradation product of aloin, formed over weeks of storage, was able to significantly inhibit insulin fibrillation. The activity of the stored aloin was significantly reduced in the presence of small amounts of sodium azide or ascorbic acid, suggesting the active compound to be an oxidation product. A high-performance liquid chromatography method and a liquid chromatography-mass spectrometry method were developed to investigate the degradation products in the aged aloin solution. We found that the major compounds in the solution were aloin A and aloin B. In addition, 10-hydroxy aloin and elgonica dimers were detected in smaller amounts. The identified compounds were isolated and tested for activity by means of Thioflavin T assays, but no activity was observed. Thus, the actual fibrillation inhibitor is an as yet unidentified and potentially metastable degradation product of aloin. These results suggest that degradation products, and in particular oxidation products, are to be considered thoroughly when natural products are investigated for activity against protein fibrillation.

  6. The Inhibitory Effect of Natural Products on Protein Fibrillation May Be Caused by Degradation Products--A Study Using Aloin and Insulin.

    Science.gov (United States)

    Lobbens, Eva S; Foderà, Vito; Nyberg, Nils T; Andersen, Kirsten; Jäger, Anna K; Jorgensen, Lene; van de Weert, Marco

    2016-01-01

    Protein fibrillation is the pathological hallmark of several neurodegenerative diseases and also complicates the manufacturing and use of protein drugs. As a case study, the inhibitory activity of the natural compound aloin against insulin fibrillation was investigated. Based on Thioflavin T assays, high-performance liquid chromatography and transmission electron microscopy it was found that a degradation product of aloin, formed over weeks of storage, was able to significantly inhibit insulin fibrillation. The activity of the stored aloin was significantly reduced in the presence of small amounts of sodium azide or ascorbic acid, suggesting the active compound to be an oxidation product. A high-performance liquid chromatography method and a liquid chromatography-mass spectrometry method were developed to investigate the degradation products in the aged aloin solution. We found that the major compounds in the solution were aloin A and aloin B. In addition, 10-hydroxy aloin and elgonica dimers were detected in smaller amounts. The identified compounds were isolated and tested for activity by means of Thioflavin T assays, but no activity was observed. Thus, the actual fibrillation inhibitor is an as yet unidentified and potentially metastable degradation product of aloin. These results suggest that degradation products, and in particular oxidation products, are to be considered thoroughly when natural products are investigated for activity against protein fibrillation.

  7. The Inhibitory Effect of Natural Products on Protein Fibrillation May Be Caused by Degradation Products – A Study Using Aloin and Insulin

    Science.gov (United States)

    Lobbens, Eva S.; Foderà, Vito; Nyberg, Nils T.; Andersen, Kirsten; Jäger, Anna K.; Jorgensen, Lene; van de Weert, Marco

    2016-01-01

    Protein fibrillation is the pathological hallmark of several neurodegenerative diseases and also complicates the manufacturing and use of protein drugs. As a case study, the inhibitory activity of the natural compound aloin against insulin fibrillation was investigated. Based on Thioflavin T assays, high-performance liquid chromatography and transmission electron microscopy it was found that a degradation product of aloin, formed over weeks of storage, was able to significantly inhibit insulin fibrillation. The activity of the stored aloin was significantly reduced in the presence of small amounts of sodium azide or ascorbic acid, suggesting the active compound to be an oxidation product. A high-performance liquid chromatography method and a liquid chromatography-mass spectrometry method were developed to investigate the degradation products in the aged aloin solution. We found that the major compounds in the solution were aloin A and aloin B. In addition, 10-hydroxy aloin and elgonica dimers were detected in smaller amounts. The identified compounds were isolated and tested for activity by means of Thioflavin T assays, but no activity was observed. Thus, the actual fibrillation inhibitor is an as yet unidentified and potentially metastable degradation product of aloin. These results suggest that degradation products, and in particular oxidation products, are to be considered thoroughly when natural products are investigated for activity against protein fibrillation. PMID:26882071

  8. A disulfide-linked amyloid-beta peptide dimer forms a protofibril-like oligomer through a distinct pathway from amyloid fibril formation.

    Science.gov (United States)

    Yamaguchi, Takahiro; Yagi, Hisashi; Goto, Yuji; Matsuzaki, Katsumi; Hoshino, Masaru

    2010-08-24

    The conversion of the soluble, nontoxic amyloid-beta (Abeta) peptide into an aggregated, toxic form rich in beta-sheets is considered a key step in the development of Alzheimer's disease. Whereas growing evidence indicates that the Abeta amyloid fibrils consist of in-register parallel beta-sheets, little is known about the structure of soluble oligomeric intermediates because of their transient nature. To understand the mechanism by which amyloid fibrils form, especially the initial development of the "nucleus" oligomeric intermediates, we prepared covalently linked dimeric Abeta peptides and analyzed the kinetics of the fibril-forming process. A covalent bond introduced between two Abeta molecules dramatically facilitated the spontaneous formation of aggregates with a beta-sheet structure and affinity for thioflavin T. Transmission electron microscopy revealed, however, that these aggregates differed in morphology from amyloid fibrils, more closely resembling protofibrils. The protofibril-like aggregates were not the most thermodynamically stable state but were a kinetically trapped state. The results emphasize the importance of the conformational flexibility of the Abeta molecule and a balance in the association and dissociation rate for the formation of rigid amyloid fibrils.

  9. Age-related changes in human tendo calcaneus collagen fibrils

    International Nuclear Information System (INIS)

    Sargon, Mustafa F.; Ozlu, Korhan; Oken, Fuad

    2005-01-01

    The ruptures of tendo calcaneus often occur between the age group of 30-45 years as described by several text books. It is also described that some diseases and drugs are said to be responsible in the etiology; however, there are no studies related with the detailed histological structure of collagen fibrils found in the tendon in the age groups of humans. In view there of, this study was aimed to obtain further information on the etiology and to find an answer regarding the frequency the ruptures occurring between the age of 30-45 years in human. In the study, the biopsy specimen taken from 28 patients age (1-68) years who had undergone surgery due to tendo calcaneus ruptures or acilloplasty operations were examined by transmission electron microscope. All the specimens were prepared according to routine electronic microscope tissue preparation technique. The patients were divided into 7 age groups (1-9, 10-19, 20-29, 30-39, 40-49, 50-59, >60 years) and there were 4 patients in each group. The transverse diameters of collagen fibers were measured from the ultra thin sections and statistical analysis of the results were performed. The study was carried out in the electron microscopy laboratory of the Anatomy Department of Hacettepe University, Ankara, Turkey between January 2004 and September 2004. The diameters of the collagen fibers were higher in the 20-29 year-old groups compared to other groups and it showed a statistically significant difference. In patients who were in the 30-39 year old group or older, the diameters of the collagen fibers were lesser than the 20-29 year-old group. However, an increase was observed in the collagen fibril concentration of these groups. In examination of the specimens of patients who were under 20-year old, the diameter of the collagen fibers were less than 20-29 year -old group. The electron microscopic appearance of the tissue sample of a one year-old patient had a specific organization and in this patient, both the

  10. Genetics of Atrial Fibrillation and Possible Implications for Ischemic Stroke

    Directory of Open Access Journals (Sweden)

    Robin Lemmens

    2011-01-01

    Full Text Available Atrial fibrillation is the most common cardiac arrhythmia mainly caused by valvular, ischemic, hypertensive, and myopathic heart disease. Atrial fibrillation can occur in families suggesting a genetic background especially in younger subjects. Additionally recent studies have identified common genetic variants to be associated with atrial fibrillation in the general population. This cardiac arrhythmia has important public health implications because of its main complications: congestive heart failure and ischemic stroke. Since atrial fibrillation can result in ischemic stroke, one might assume that genetic determinants of this cardiac arrhythmia are also implicated in cerebrovascular disease. Ischemic stroke is a multifactorial, complex disease where multiple environmental and genetic factors interact. Whether genetic variants associated with a risk factor for ischemic stroke also increase the risk of a particular vascular endpoint still needs to be confirmed in many cases. Here we review the current knowledge on the genetic background of atrial fibrillation and the consequences for cerebrovascular disease.

  11. Combinatorial release of dexamethasone and amiodarone from a nano-structured parylene-C film to reduce perioperative inflammation and atrial fibrillation

    Science.gov (United States)

    Robinson, Erik; Kaushal, Sunjay; Alaboson, Justice; Sharma, Sudhish; Belagodu, Amogh; Watkins, Claire; Walker, Brandon; Webster, Gregory; McCarthy, Patrick; Ho, Dean

    2016-02-01

    Suppressing perioperative inflammation and post-operative atrial fibrillation requires effective drug delivery platforms (DDP). Localized anti-inflammatory and anti-arrhythmic agent release may be more effective than intravenous treatment to improve patient outcomes. This study utilized a dexamethasone (DEX) and amiodarone (AMIO)-loaded Parylene-C (PPX) nano-structured film to inhibit inflammation and atrial fibrillation. The PPX film was tested in an established pericardial adhesion rabbit model. Following sternotomy, the anterior pericardium was resected and the epicardium was abraded. Rabbits were randomly assigned to five treatment groups: control, oxidized PPX (PPX-Oxd), PPX-Oxd infused with DEX (PPX-Oxd[DEX]), native PPX (PPX), and PPX infused with DEX and AMIO (PPX[AMIO, DEX]). 4 weeks post-sternotomy, pericardial adhesions were evaluated for gross adhesions using a 4-point grading system and histological evaluation for epicardial neotissue fibrosis (NTF). Atrial fibrillation duration and time per induction were measured. The PPX[AMIO, DEX] group had a significant reduction in mean adhesion score compared with the control group (control 2.75 +/- 0.42 vs. PPX[AMIO, DEX] 0.25 +/- 0.42, P atrial fibrillation was decreased in rabbits with PPX[AMIO, DEX] films compared to control (9.5 +/- 6.8 s vs. 187.6 +/- 174.7 s, p = 0.003). Time of atrial fibrillation per successful induction decreased among PPX[AMIO, DEX] films compared to control (2.8 +/- 1.2 s vs. 103.2 +/- 178 s, p = 0.004). DEX/AMIO-loaded PPX films are associated with reduced perioperative inflammation and a diminished atrial fibrillation duration. Epicardial application of AMIO, DEX films is a promising strategy to prevent post-operative cardiac complications.Suppressing perioperative inflammation and post-operative atrial fibrillation requires effective drug delivery platforms (DDP). Localized anti-inflammatory and anti-arrhythmic agent release may be more effective than intravenous treatment to

  12. Integrating new approaches to atrial fibrillation management

    DEFF Research Database (Denmark)

    Kotecha, Dipak; Breithardt, Günter; Camm, A John

    2018-01-01

    cardiovascular events. New approaches to AF management, including the use of novel technologies and structured, integrated care, have the potential to enhance clinical phenotyping or result in better treatment selection and stratified therapy. Here, we report the outcomes of the 6th Consensus Conference...... of the Atrial Fibrillation Network (AFNET) and the European Heart Rhythm Association (EHRA), held at the European Society of Cardiology Heart House in Sophia Antipolis, France, 17-19 January 2017. Sixty-two global specialists in AF and 13 industry partners met to develop innovative solutions based on new...

  13. NASA's First Atrial Fibrillation Case - Deke Slayton

    Science.gov (United States)

    Tarver, William J.

    2010-01-01

    Concerns about heart dysrhythmia have been present since the earliest days of the US manned space program. While information about an astronaut's health is general kept private, one of the original seven American astronaut's health status was played out in a very public forum. Donald "Deke" Slayton was removed from the second manned space flight when it was discovered he had idiopathic atrial fibrillation. Referencing the original medical documents, details of how this was discovered and managed from the medical perspective will be reviewed. This is NASA's first heart dysrhythmia case in an astronaut and it proves quite interesting when placed in historic perspective.

  14. Negatively charged food additive dye "Allura Red" rapidly induces SDS-soluble amyloid fibril in beta-lactoglobulin protein.

    Science.gov (United States)

    Al-Shabib, Nasser Abdulatif; Khan, Javed Masood; Malik, Ajamaluddin; Alsenaidy, Abdulrahman M; Alsenaidy, Mohammad A; Husain, Fohad Mabood; Shamsi, Monis Bilal; Hidayathulla, Syed; Khan, Rizwan Hasan

    2018-02-01

    Recent studies have led to an increased interest to categorize small molecular inhibitors of protein fibrillation. In this study, we used spectroscopy, microscopy and gel electrophoresis techniques that provides an elaborated description of the Allura Red-induced amyloid fibrillation in the β-LG protein at two pHs (7.4 and 3.5). The spectroscopy results show that β-LG protein form aggregates in the presence of Allura Red (0.04-15.0mM) at pH 3.5 due to electrostatic and hydrophobic interactions. However, at pH 7.4, the β-LG does not interact electrostatically with Allura Red and therefore no aggregation occurred. The Allura Red-induced aggregates have an amyloid-like structure that was confirmed by far-UV CD, Congo Red and transmission electron microscopy (TEM). The CD spectrum of β-LG contains single minima at ∼218nm, which shifts towards higher wavelength minima at ∼225nm in the presence of Allura Red, characteristics of the cross β-sheet structure. The TEM results suggest that β-LG form long straight fibril when exposed to Allura Red at pH 3.5. The Allura Red-induced amyloid fibril is SDS-soluble confirmed by SDS-PAGE techniques. A far UV CD result shows the conversion of Allura Red induced cross β-sheet structure into alpha-helical structure in the presence of increasing concentration of SDS. The results of this study suggest that the electrostatic, as well as hydrophobic interactions play an important role during Allura Red-induced β-LG fibrillation. Copyright © 2017. Published by Elsevier B.V.

  15. Potassium channel gene mutations rarely cause atrial fibrillation

    Directory of Open Access Journals (Sweden)

    Nam Edwin G

    2006-08-01

    Full Text Available Abstract Background Mutations in several potassium channel subunits have been associated with rare forms of atrial fibrillation. In order to explore the role of potassium channels in inherited typical forms of the arrhythmia, we have screened a cohort of patients from a referral clinic for mutations in the channel subunit genes implicated in the arrhythmia. We sought to determine if mutations in KCNJ2 and KCNE1-5 are a common cause of atrial fibrillation. Methods Serial patients with lone atrial fibrillation or atrial fibrillation with hypertension were enrolled between June 1, 2001 and January 6, 2005. Each patient underwent a standardized interview and physical examination. An electrocardiogram, echocardiogram and blood sample for genetic analysis were also obtained. Patients with a family history of AF were screened for mutations in KCNJ2 and KCNE1-5 using automated sequencing. Results 96 patients with familial atrial fibrillation were enrolled. Eighty-three patients had lone atrial fibrillation and 13 had atrial fibrillation and hypertension. Patients had a mean age of 56 years at enrollment and 46 years at onset of atrial fibrillation. Eighty-one percent of patients had paroxysmal atrial fibrillation at enrollment. Unlike patients with an activating mutation in KCNQ1, the patients had a normal QTc interval with a mean of 412 ± 42 ms. Echocardiography revealed a normal mean ejection fraction of 62.0 ± 7.2 % and mean left atrial dimension of 39.9 ± 7.0 mm. A number of common polymorphisms in KCNJ2 and KCNE1-5 were identified, but no mutations were detected. Conclusion Mutations in KCNJ2 and KCNE1-5 rarely cause typical atrial fibrillation in a referral clinic population.

  16. The contrasting effect of macromolecular crowding on amyloid fibril formation.

    Directory of Open Access Journals (Sweden)

    Qian Ma

    Full Text Available Amyloid fibrils associated with neurodegenerative diseases can be considered biologically relevant failures of cellular quality control mechanisms. It is known that in vivo human Tau protein, human prion protein, and human copper, zinc superoxide dismutase (SOD1 have the tendency to form fibril deposits in a variety of tissues and they are associated with different neurodegenerative diseases, while rabbit prion protein and hen egg white lysozyme do not readily form fibrils and are unlikely to cause neurodegenerative diseases. In this study, we have investigated the contrasting effect of macromolecular crowding on fibril formation of different proteins.As revealed by assays based on thioflavin T binding and turbidity, human Tau fragments, when phosphorylated by glycogen synthase kinase-3β, do not form filaments in the absence of a crowding agent but do form fibrils in the presence of a crowding agent, and the presence of a strong crowding agent dramatically promotes amyloid fibril formation of human prion protein and its two pathogenic mutants E196K and D178N. Such an enhancing effect of macromolecular crowding on fibril formation is also observed for a pathological human SOD1 mutant A4V. On the other hand, rabbit prion protein and hen lysozyme do not form amyloid fibrils when a crowding agent at 300 g/l is used but do form fibrils in the absence of a crowding agent. Furthermore, aggregation of these two proteins is remarkably inhibited by Ficoll 70 and dextran 70 at 200 g/l.We suggest that proteins associated with neurodegenerative diseases are more likely to form amyloid fibrils under crowded conditions than in dilute solutions. By contrast, some of the proteins that are not neurodegenerative disease-associated are unlikely to misfold in crowded physiological environments. A possible explanation for the contrasting effect of macromolecular crowding on these two sets of proteins (amyloidogenic proteins and non-amyloidogenic proteins has been

  17. Progression of atrial fibrillation in the REgistry on Cardiac rhythm disORDers assessing the control of Atrial Fibrillation cohort

    DEFF Research Database (Denmark)

    De Vos, Cees B; Breithardt, Günter; Camm, A John

    2012-01-01

    Paroxysmal atrial fibrillation (AF) may progress to persistent AF. We studied the clinical correlates and the effect of rhythm-control strategy on AF progression.......Paroxysmal atrial fibrillation (AF) may progress to persistent AF. We studied the clinical correlates and the effect of rhythm-control strategy on AF progression....

  18. Tornado risk model for transmission line design

    CSIR Research Space (South Africa)

    Milford, RV

    1997-11-01

    Full Text Available is in combination with ice loading. The wind load used in most codes of practice and design recommendations for transmission line design have until recently been based almost exclusively on large-scale wind storms, which may include severe storms such as hurricanes...

  19. Seeded fibrillation as molecular basis of the species barrier in human prion diseases.

    Directory of Open Access Journals (Sweden)

    Lars Luers

    Full Text Available Prion diseases are transmissible spongiform encephalopathies in humans and animals, including scrapie in sheep, bovine spongiform encephalopathy (BSE in cattle, chronic wasting disease (CWD in deer, and Creutzfeldt-Jakob disease (CJD in humans. The hallmark of prion diseases is the conversion of the host-encoded prion protein (PrP(C to its pathological isoform PrP(Sc, which is accompanied by PrP fibrillation. Transmission is not restricted within one species, but can also occur between species. In some cases a species barrier can be observed that results in limited or unsuccessful transmission. The mechanism behind interspecies transmissibility or species barriers is not completely understood. To analyse this process at a molecular level, we previously established an in vitro fibrillation assay, in which recombinant PrP (recPrP as substrate can be specifically seeded by PrP(Sc as seed. Seeding with purified components, with no additional cellular components, is a direct consequence of the "prion-protein-only" hypothesis. We therefore hypothesise, that the species barrier is based on the interaction of PrP(C and PrP(Sc. Whereas in our earlier studies, the interspecies transmission in animal systems was analysed, the focus of this study lies on the transmission from animals to humans. We therefore combined seeds from species cattle, sheep and deer (BSE, scrapie, CWD with human recPrP. Homologous seeding served as a control. Our results are consistent with epidemiology, other in vitro aggregation studies, and bioassays investigating the transmission between humans, cattle, sheep, and deer. In contrast to CJD and BSE seeds, which show a seeding activity we can demonstrate a species barrier for seeds from scrapie and CWD in vitro. We could show that the seeding activity and therewith the molecular interaction of PrP as substrate and PrP(Sc as seed is sufficient to explain the phenomenon of species barriers. Therefore our data supports the hypothesis

  20. Fecal transmission of AA amyloidosis in the cheetah contributes to high incidence of disease

    Science.gov (United States)

    Zhang, Beiru; Une, Yumi; Fu, Xiaoying; Yan, Jingmin; Ge, FengXia; Yao, Junjie; Sawashita, Jinko; Mori, Masayuki; Tomozawa, Hiroshi; Kametani, Fuyuki; Higuchi, Keiichi

    2008-01-01

    AA amyloidosis is one of the principal causes of morbidity and mortality in captive cheetahs (Acinonyx jubatus), which are in danger of extinction, but little is known about the underlying mechanisms. Given the transmissible characteristics of AA amyloidosis, transmission between captive cheetahs may be a possible mechanism involved in the high incidence of AA amyloidosis. In this study of animals with AA amyloidosis, we found that cheetah feces contained AA amyloid fibrils that were different from those of the liver with regard to molecular weight and shape and had greater transmissibility. The infectious activity of fecal AA amyloid fibrils was reduced or abolished by the protein denaturants 6 M guanidine·HCl and formic acid or by AA immunodepletion. Thus, we propose that feces are a vehicle of transmission that may accelerate AA amyloidosis in captive cheetah populations. These results provide a pathogenesis for AA amyloidosis and suggest possible measures for rescuing cheetahs from extinction. PMID:18474855

  1. Increased amount of atrial fibrosis in patients with atrial fibrillation secondary to mitral valve disease

    NARCIS (Netherlands)

    Geuzebroek, Guillaume S. C.; van Amersfoorth, Shirley C. M.; Hoogendijk, Mark G.; Kelder, Johannes C.; van Hemel, Norbert M.; de Bakker, Jacques M. T.; Coronel, Ruben

    2012-01-01

    Objective: Atrial fibrosis is related to atrial fibrillation but may differ in patients with mitral valve disease or lone atrial fibrillation. Therefore, we studied atrial fibrosis in patients with atrial fibrillation + mitral valve disease or with lone atrial fibrillation and compared it with

  2. Atrial Fibrillation: When the heart is not in rhythm | NIH MedlinePlus the Magazine

    Science.gov (United States)

    ... of this page please turn JavaScript on. Feature: Atrial Fibrillation Atrial Fibrillation: When the heart is not in rhythm Past ... show, Deal With It . Photo: TBS/Deal Understanding Atrial Fibrillation Atrial fibrillation (AFib) is the most common type ...

  3. Immunoprecipitation of amyloid fibrils by the use of an antibody that recognizes a generic epitope common to amyloid fibrils.

    Directory of Open Access Journals (Sweden)

    Erin R Greiner

    Full Text Available Amyloid fibrils are associated with many maladies, including Alzheimer's disease (AD. The isolation of amyloids from natural materials is very challenging because the extreme structural stability of amyloid fibrils makes it difficult to apply conventional protein science protocols to their purification. A protocol to isolate and detect amyloids is desired for the diagnosis of amyloid diseases and for the identification of new functional amyloids. Our aim was to develop a protocol to purify amyloid from organisms, based on the particular characteristics of the amyloid fold, such as its resistance to proteolysis and its capacity to be recognized by specific conformational antibodies. We used a two-step strategy with proteolytic digestion as the first step followed by immunoprecipitation using the amyloid conformational antibody LOC. We tested the efficacy of this method using as models amyloid fibrils produced in vitro, tissue extracts from C. elegans that overexpress Aβ peptide, and cerebrospinal fluid (CSF from patients diagnosed with AD. We were able to immunoprecipitate Aβ(1-40 amyloid fibrils, produced in vitro and then added to complex biological extracts, but not α-synuclein and gelsolin fibrils. This method was useful for isolating amyloid fibrils from tissue homogenates from a C. elegans AD model, especially from aged worms. Although we were able to capture picogram quantities of Aβ(1-40 amyloid fibrils produced in vitro when added to complex biological solutions, we could not detect any Aβ amyloid aggregates in CSF from AD patients. Our results show that although immunoprecipitation using the LOC antibody is useful for isolating Aβ(1-40 amyloid fibrils, it fails to capture fibrils of other amyloidogenic proteins, such as α-synuclein and gelsolin. Additional research might be needed to improve the affinity of these amyloid conformational antibodies for an array of amyloid fibrils without compromising their selectivity before

  4. [Progress of anticoagulation therapy in atrial fibrillation].

    Science.gov (United States)

    Hernández Olmedo, Miguel; Suárez Fernández, Carmen

    2015-08-07

    Atrial fibrillation is currently a very prevalent disease and it represents one of the most common causes of disabling stroke. Antithrombotic therapies have reduced the incidence of this complication although they pose many limitations and difficulties. As a result, a large number of high risk patients do not receive an appropriate treatment. In recent years, four new oral anticoagulants (NOAC) with relevant advantages in comparison to vitaminK antagonists have been released. Four large phaseiii clinical trials have demonstrated that NOAC are at least as safe and efficacious as warfarin in stroke prevention in non-valve atrial fibrillation patients with moderate-high thrombotic risk, being their main advantage the reduction in intracranial hemorrhage. The arrival of these drugs has caused great expectations in the management of these patients but also new doubts. Lacking data in some subgroups of frail patients, the absence of specific antidotes available and specially their high cost represent nowadays the main limitations for their generalization. Copyright © 2014 Elsevier España, S.L.U. All rights reserved.

  5. Atrial fibrillation: an observational study with outpatients.

    Science.gov (United States)

    Albina, Gastón; De Luca, Julián; Conde, Diego; Giniger, Alberto

    2014-11-01

    Atrial fibrillation (AF) is the most common sustained arrhythmia with serious clinical consequences in the absence of treatment. However, there are limited data on the treatment of these patients in Argentina. The objective was to describe the therapeutic management of patients with nonacute AF by Argentinean cardiologists and to determine the incidence of clinical events after 12 months follow-up. The Atrial Fibrillation study in Argentina (FARAON) was an observational, descriptive, prospective, national, and multicentric study that included outpatients with AF, followed for 12 months. The study included 38 sites in Argentina. Each researcher included the first 10 patients who met the inclusion criteria of being over 21 and also being an AF carrier documented by electrocardiogram or Holter within 12 months prior to or at the time of enrollment. A total of 373 patients were included, mean age 70 ± 11.5 years, 40% women; 65% had AF rhythm at the time of inclusion, 57% had permanent AF, and 56% were asymptomatic. At the time of enrollment, 40% of physicians opted for rhythm control strategy. β-blockers and amiodarone were the most used drugs. Patients with rhythm control drugs had higher success rate than those with frequency control drug therapy (80% vs 57%). Cardiologists in Argentina receive patients with AF that are mostly permanent AF. More than half of the patients are asymptomatic. They opt primarily by controlling the pace. When choosing antiarrhythmic drugs, nearly half of them indicated amiodarone. © 2014 Wiley Periodicals, Inc.

  6. Load forecasting

    International Nuclear Information System (INIS)

    Mak, H.

    1995-01-01

    Slides used in a presentation at The Power of Change Conference in Vancouver, BC in April 1995 about the changing needs for load forecasting were presented. Technological innovations and population increase were said to be the prime driving forces behind the changing needs in load forecasting. Structural changes, market place changes, electricity supply planning changes, and changes in planning objectives were other factors discussed. It was concluded that load forecasting was a form of information gathering, that provided important market intelligence

  7. Sequence dependent aggregation of peptides and fibril formation

    Science.gov (United States)

    Hung, Nguyen Ba; Le, Duy-Manh; Hoang, Trinh X.

    2017-09-01

    Deciphering the links between amino acid sequence and amyloid fibril formation is key for understanding protein misfolding diseases. Here we use Monte Carlo simulations to study the aggregation of short peptides in a coarse-grained model with hydrophobic-polar (HP) amino acid sequences and correlated side chain orientations for hydrophobic contacts. A significant heterogeneity is observed in the aggregate structures and in the thermodynamics of aggregation for systems of different HP sequences and different numbers of peptides. Fibril-like ordered aggregates are found for several sequences that contain the common HPH pattern, while other sequences may form helix bundles or disordered aggregates. A wide variation of the aggregation transition temperatures among sequences, even among those of the same hydrophobic fraction, indicates that not all sequences undergo aggregation at a presumable physiological temperature. The transition is found to be the most cooperative for sequences forming fibril-like structures. For a fibril-prone sequence, it is shown that fibril formation follows the nucleation and growth mechanism. Interestingly, a binary mixture of peptides of an aggregation-prone and a non-aggregation-prone sequence shows the association and conversion of the latter to the fibrillar structure. Our study highlights the role of a sequence in selecting fibril-like aggregates and also the impact of a structural template on fibril formation by peptides of unrelated sequences.

  8. Cold denaturation of α-synuclein amyloid fibrils.

    Science.gov (United States)

    Ikenoue, Tatsuya; Lee, Young-Ho; Kardos, József; Saiki, Miyu; Yagi, Hisashi; Kawata, Yasushi; Goto, Yuji

    2014-07-21

    Although amyloid fibrils are associated with numerous pathologies, their conformational stability remains largely unclear. Herein, we probe the thermal stability of various amyloid fibrils. α-Synuclein fibrils cold-denatured to monomers at 0-20 °C and heat-denatured at 60-110 °C. Meanwhile, the fibrils of β2-microglobulin, Alzheimer's Aβ1-40/Aβ1-42 peptides, and insulin exhibited only heat denaturation, although they showed a decrease in stability at low temperature. A comparison of structural parameters with positive enthalpy and heat capacity changes which showed opposite signs to protein folding suggested that the burial of charged residues in fibril cores contributed to the cold denaturation of α-synuclein fibrils. We propose that although cold-denaturation is common to both native proteins and misfolded fibrillar states, the main-chain dominated amyloid structures may explain amyloid-specific cold denaturation arising from the unfavorable burial of charged side-chains in fibril cores. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Replica Exchange Simulations of the Thermodynamics of Aβ Fibril Growth

    Science.gov (United States)

    Takeda, Takako; Klimov, Dmitri K.

    2009-01-01

    Abstract Replica exchange molecular dynamics and an all-atom implicit solvent model are used to probe the thermodynamics of deposition of Alzheimer's Aβ monomers on preformed amyloid fibrils. Consistent with the experiments, two deposition stages have been identified. The docking stage occurs over a wide temperature range, starting with the formation of the first peptide-fibril interactions at 500 K. Docking is completed when a peptide fully adsorbs on the fibril edge at the temperature of 380 K. The docking transition appears to be continuous, and occurs without free energy barriers or intermediates. During docking, incoming Aβ monomer adopts a disordered structure on the fibril edge. The locking stage occurs at the temperature of ≈360 K and is characterized by the rugged free energy landscape. Locking takes place when incoming Aβ peptide forms a parallel β-sheet structure on the fibril edge. Because the β-sheets formed by locked Aβ peptides are typically off-registry, the structure of the locked phase differs from the structure of the fibril interior. The study also reports that binding affinities of two distinct fibril edges with respect to incoming Aβ peptides are different. The peptides bound to the concave edge have significantly lower free energy compared to those bound on the convex edge. Comparison with the available experimental data is discussed. PMID:19167295

  10. Detection of amyloid fibrils in Parkinson's disease using plasmonic chirality.

    Science.gov (United States)

    Kumar, Jatish; Eraña, Hasier; López-Martínez, Elena; Claes, Nathalie; Martín, Víctor F; Solís, Diego M; Bals, Sara; Cortajarena, Aitziber L; Castilla, Joaquín; Liz-Marzán, Luis M

    2018-03-27

    Amyloid fibrils, which are closely associated with various neurodegenerative diseases, are the final products in many protein aggregation pathways. The identification of fibrils at low concentration is, therefore, pivotal in disease diagnosis and development of therapeutic strategies. We report a methodology for the specific identification of amyloid fibrils using chiroptical effects in plasmonic nanoparticles. The formation of amyloid fibrils based on α-synuclein was probed using gold nanorods, which showed no apparent interaction with monomeric proteins but effective adsorption onto fibril structures via noncovalent interactions. The amyloid structure drives a helical nanorod arrangement, resulting in intense optical activity at the surface plasmon resonance wavelengths. This sensing technique was successfully applied to human brain homogenates of patients affected by Parkinson's disease, wherein protein fibrils related to the disease were identified through chiral signals from Au nanorods in the visible and near IR, whereas healthy brain samples did not exhibit any meaningful optical activity. The technique was additionally extended to the specific detection of infectious amyloids formed by prion proteins, thereby confirming the wide potential of the technique. The intense chiral response driven by strong dipolar coupling in helical Au nanorod arrangements allowed us to detect amyloid fibrils down to nanomolar concentrations.

  11. Proinsulin C-peptide interferes with insulin fibril formation

    International Nuclear Information System (INIS)

    Landreh, Michael; Stukenborg, Jan-Bernd; Willander, Hanna; Söder, Olle; Johansson, Jan; Jörnvall, Hans

    2012-01-01

    Highlights: ► Insulin and C-peptide can interact under insulin fibril forming conditions. ► C-peptide is incorporated into insulin aggregates and alters aggregation lag time. ► C-peptide changes insulin fibril morphology and affects backbone accessibility. ► C-peptide may be a regulator of fibril formation by β-cell granule proteins. -- Abstract: Insulin aggregation can prevent rapid insulin uptake and cause localized amyloidosis in the treatment of type-1 diabetes. In this study, we investigated the effect of C-peptide, the 31-residue peptide cleaved from proinsulin, on insulin fibrillation at optimal conditions for fibrillation. This is at low pH and high concentration, when the fibrils formed are regular and extended. We report that C-peptide then modulates the insulin aggregation lag time and profoundly changes the fibril appearance, to rounded clumps of short fibrils, which, however, still are Thioflavine T-positive. Electrospray ionization mass spectrometry also indicates that C-peptide interacts with aggregating insulin and is incorporated into the aggregates. Hydrogen/deuterium exchange mass spectrometry further reveals reduced backbone accessibility in insulin aggregates formed in the presence of C-peptide. Combined, these effects are similar to those of C-peptide on islet amyloid polypeptide fibrillation and suggest that C-peptide has a general ability to interact with amyloidogenic proteins from pancreatic β-cell granules. Considering the concentrations, these peptide interactions should be relevant also during physiological secretion, and even so at special sites post-secretory or under insulin treatment conditions in vivo.

  12. Modeling of Electromagnetic Wave Propagation with Tapered Transmission Line

    Science.gov (United States)

    Lee, Kun-A.; Ko, Kwang-Cheol

    2012-09-01

    Tapered transmission line was used for impedance matching, for high voltage pulse, and atmospheric medium is applied to characteristic equation of tapered transmission line and reflection coefficient so that nonlinear load and circuit modeling of atmospheric medium was simulated by electromagnetic transient program (EMTP). A characteristic of atmospheric medium and Time delay are decided by inductance and capacitance of tapered transmission line. For electromagnetic wave propagation modeling, in this paper, tapered transmission line is implemented. It is difficult to model tapered transmission line directly. Other transmission line that can be expressed by the circuit is used. So object of this paper is efficient modeling of tapered transmission line.

  13. Long working hours as a risk factor for atrial fibrillation

    DEFF Research Database (Denmark)

    Kivimäki, Mika; Nyberg, Solja T.; Batty, G. David

    2017-01-01

    Aims Studies suggest that people who work long hours are at increased risk of stroke, but the association of long working hours with atrial fibrillation, the most common cardiac arrhythmia and a risk factor for stroke, is unknown. We examined the risk of atrial fibrillation in individuals working...... confounding factors, such as obesity, risky alcohol use and high blood pressure, had little impact on this association. Conclusion Individuals who worked long hours were more likely to develop atrial fibrillation than those working standard hours....

  14. Rivaroxaban versus warfarin in nonvalvular atrial fibrillation.

    Science.gov (United States)

    Patel, Manesh R; Mahaffey, Kenneth W; Garg, Jyotsna; Pan, Guohua; Singer, Daniel E; Hacke, Werner; Breithardt, Günter; Halperin, Jonathan L; Hankey, Graeme J; Piccini, Jonathan P; Becker, Richard C; Nessel, Christopher C; Paolini, John F; Berkowitz, Scott D; Fox, Keith A A; Califf, Robert M

    2011-09-08

    The use of warfarin reduces the rate of ischemic stroke in patients with atrial fibrillation but requires frequent monitoring and dose adjustment. Rivaroxaban, an oral factor Xa inhibitor, may provide more consistent and predictable anticoagulation than warfarin. In a double-blind trial, we randomly assigned 14,264 patients with nonvalvular atrial fibrillation who were at increased risk for stroke to receive either rivaroxaban (at a daily dose of 20 mg) or dose-adjusted warfarin. The per-protocol, as-treated primary analysis was designed to determine whether rivaroxaban was noninferior to warfarin for the primary end point of stroke or systemic embolism. In the primary analysis, the primary end point occurred in 188 patients in the rivaroxaban group (1.7% per year) and in 241 in the warfarin group (2.2% per year) (hazard ratio in the rivaroxaban group, 0.79; 95% confidence interval [CI], 0.66 to 0.96; P<0.001 for noninferiority). In the intention-to-treat analysis, the primary end point occurred in 269 patients in the rivaroxaban group (2.1% per year) and in 306 patients in the warfarin group (2.4% per year) (hazard ratio, 0.88; 95% CI, 0.74 to 1.03; P<0.001 for noninferiority; P=0.12 for superiority). Major and nonmajor clinically relevant bleeding occurred in 1475 patients in the rivaroxaban group (14.9% per year) and in 1449 in the warfarin group (14.5% per year) (hazard ratio, 1.03; 95% CI, 0.96 to 1.11; P=0.44), with significant reductions in intracranial hemorrhage (0.5% vs. 0.7%, P=0.02) and fatal bleeding (0.2% vs. 0.5%, P=0.003) in the rivaroxaban group. In patients with atrial fibrillation, rivaroxaban was noninferior to warfarin for the prevention of stroke or systemic embolism. There was no significant between-group difference in the risk of major bleeding, although intracranial and fatal bleeding occurred less frequently in the rivaroxaban group. (Funded by Johnson & Johnson and Bayer; ROCKET AF ClinicalTrials.gov number, NCT00403767.).

  15. Transcending Transmission

    DEFF Research Database (Denmark)

    Schoeneborn, Dennis; Trittin, Hannah

    2013-01-01

    Purpose – Extant research on corporate social responsibility (CSR) communication primarily relies on a transmission model of communication that treats organizations and communication as distinct phenomena. This approach has been criticized for neglecting the formative role of communication...... in the emergence of organizations. This paper seeks to propose to reconceptualize CSR communication by drawing on the “communication constitutes organizations” (CCO) perspective. Design/methodology/approach – This is a conceptual paper that explores the implications of switching from an instrumental...... are stabilized by various non-human entities that “act” on their behalf. Accordingly, CSR communication should also take into account non-human agency and responsibility. Originality/value – This paper links the literature on CSR communication to broader debates in organizational communication studies and...

  16. Collagen fibril surface displays a constellation of sites capable of promoting fibril assembly, stability, and hemostasis

    Energy Technology Data Exchange (ETDEWEB)

    Orgel, J.P.; Antipova, O.; Sagi, I.; Bitler, A.; Qiu, D.; Wang, R.; Xu, Y.; San Antonio, J.D. (IIT)

    2011-12-14

    Fibrillar collagens form the structural basis of organs and tissues including the vasculature, bone, and tendon. They are also dynamic, organizational scaffolds that present binding and recognition sites for ligands, cells, and platelets. We interpret recently published X-ray diffraction findings and use atomic force microscopy data to illustrate the significance of new insights into the functional organization of the collagen fibril. These data indicate that collagen's most crucial functional domains localize primarily to the overlap region, comprising a constellation of sites we call the 'master control region.' Moreover, the collagen's most exposed aspect contains its most stable part - the C-terminal region that controls collagen assembly, cross-linking, and blood clotting. Hidden beneath the fibril surface exists a constellation of 'cryptic' sequences poised to promote hemostasis and cell - collagen interactions in tissue injury and regeneration. These findings begin to address several important, and previously unresolved, questions: How functional domains are organized in the fibril, which domains are accessible, and which require proteolysis or structural trauma to become exposed? Here we speculate as to how collagen fibrillar organization impacts molecular processes relating to tissue growth, development, and repair.

  17. Association of common genetic variants related to atrial fibrillation and the risk of ventricular fibrillation in the setting of first ST-elevation myocardial infarction

    DEFF Research Database (Denmark)

    Jabbari, Reza; Jabbari, Javad; Glinge, Charlotte

    2017-01-01

    Background: Cohort studies have revealed an increased risk for ventricular fibrillation (VF) and sudden cardiac death (SCD) in patients with atrial fibrillation (AF). In this study, we hypothesized that single nucleotide polymorphisms (SNP) previously associated with AF may be associated...

  18. A roadmap to improve the quality of atrial fibrillation management : proceedings from the fifth Atrial Fibrillation Network/European Heart Rhythm Association consensus conference

    NARCIS (Netherlands)

    Kirchhof, Paulus; Breithardt, Guenter; Bax, Jeroen; Benninger, Gerlinde; Blomstrom-Lundqvist, Carina; Boriani, Giuseppe; Brandes, Axel; Brown, Helen; Brueckmann, Martina; Calkins, Hugh; Calvert, Melanie; Christoffels, Vincent; Crijns, Harry; Dobrev, Dobromir; Ellinor, Patrick; Fabritz, Larissa; Fetsch, Thomas; Freedman, S. Ben; Gerth, Andrea; Goette, Andreas; Guasch, Eduard; Hack, Guido; Haegeli, Laurent; Hatem, Stephane; Haeusler, Karl Georg; Heidbuechel, Hein; Heinrich-Nols, Jutta; Hidden-Lucet, Francoise; Hindricks, Gerd; Juul-Moeller, Steen; Kaeaeb, Stefan; Kappenberger, Lukas; Kespohl, Stefanie; Kotecha, Dipak; Lane, Deirdre A.; Leute, Angelika; Lewalter, Thorsten; Meyer, Ralf; Mont, Lluis; Muenzel, Felix; Nabauer, Michael; Nielsen, Jens C.; Oeff, Michael; Oldgren, Jonas; Oto, Ali; Piccini, Jonathan P.; Pilmeyer, Art; Potpara, Tatjana; Ravens, Ursula; Reinecke, Holger; Rostock, Thomas; Rustige, Joerg; Savelieva, Irene; Schnabel, Renate; Schotten, Ulrich; Schwichtenberg, Lars; Sinner, Moritz F.; Steinbeck, Gerhard; Stoll, Monika; Tavazzi, Luigi; Themistoclakis, Sakis; Tse, Hung Fat; Van Gelder, Isabelle C.; Vardas, Panagiotis E.; Varpula, Timo; Vincent, Alphons; Werring, David; Willems, Stephan; Ziegler, Andre; Lip, Gregory Y. H.; Camm, A. John

    2016-01-01

    At least 30 million people worldwide carry a diagnosis of atrial fibrillation (AF), and many more suffer from undiagnosed, subclinical, or 'silent' AF. Atrial fibrillation-related cardiovascular mortality and morbidity, including cardiovascular deaths, heart failure, stroke, and hospitalizations,

  19. Clinical characteristics, management, and control of permanent vs. nonpermanent atrial fibrillation: insights from the RealiseAF survey.

    LENUS (Irish Health Repository)

    Murin, Jan

    2014-01-01

    Atrial fibrillation can be categorized into nonpermanent and permanent atrial fibrillation. There is less information on permanent than on nonpermanent atrial fibrillation patients. This analysis aimed to describe the characteristics and current management, including the proportion of patients with successful atrial fibrillation control, of these atrial fibrillation subsets in a large, geographically diverse contemporary sample.

  20. DIAGNOSTIC TOOLS FOR STRUCTURAL CHARACTERIZATION AND ELUCIDATION OF FIBRILS AND THEIR PRECURSORS IN AMYLOID FIBRIL FORMATION PATHWAY

    Directory of Open Access Journals (Sweden)

    Nidhi Kaur Bhatia

    2013-12-01

    Full Text Available The amyloid fibrils and their precursors are supposed to be responsible for several neurodegenerative diseases. Advances in recent experimental techniques rationalized our understanding on the mechanism of the amyloid fibril formation. The goal of this review is to revisit the various techniques used to diagnose the structural features of amyloid fibrils and their precursors, for a comprehensive view of the available tools, their advantages and disadvantages. The review will serve as a stepping stone for detailed understanding of each technique and its use as per specific requirements of a biological problem.

  1. Frontiers of anticoagulation therapy for atrial fibrillation.

    Science.gov (United States)

    Yamashita, Takeshi

    2011-07-01

    In the management of atrial fibrillation (AF), stroke prevention has been proved to play a pivotal role in addition to therapy for concomitant diseases. And, hitherto, anticoagulation by warfarin has been the only effective choice that is known to decrease the stroke rate with ∼70% risk reduction. Although the evidence has been rigid, there are many barriers not to make warfarin therapy pervasive. However, the principle of "KISS (keep it short and simple)" seems to alter our situations. Changing the complex pharmacology with warfarin into the simple pharmacology with new anticoagulants would lead us to a new paradigm, where the old book is now rewritten by a new language. Copyright © 2011 Japanese College of Cardiology. Published by Elsevier Ltd. All rights reserved.

  2. Initiation of anticoagulation in atrial fibrillation

    DEFF Research Database (Denmark)

    Gundlund, A.; Staerk, L.; Fosbøl, E. L.

    2017-01-01

    Background: The use of non-vitamin K antagonist oral anticoagulants (NOACs) for stroke prophylaxis in atrial fibrillation (AF) is increasing rapidly. We compared characteristics of AF patients initiated on NOACs versus vitamin K antagonists (VKAs). Methods: Using Danish nationwide registry data, we...... identified AF patients initiating either a VKA or a NOAC from 22 August 2011 until 30 September 2016. We compared patient characteristics including age, gender, comorbidities, concomitant pharmacotherapy and CHA2DS2-VASc and HAS-BLED scores in patients initiated on a VKA, dabigatran, rivaroxaban or apixaban....... Differences were examined using multivariable logistic regression models. Results: The study population comprised 51 981 AF patients of whom 19 989 (38.5%) were initiated on a VKA, 13 242 (25.5%) on dabigatran, 8475 (16.3%) on rivaroxaban and 10 275 (19.8%) on apixaban. Those patients initiated on apixaban...

  3. Prognosis of ventricular fibrillation in hospital

    DEFF Research Database (Denmark)

    Jensen, G V; Torp-Pedersen, C; Køber, L

    1992-01-01

    In a retrospective study of 520 patients with in-hospital ventricular fibrillation 421 (81%) had acute myocardial infarction (MI), 66 (13%) had ischaemic heart disease (IHD) without MI, 33 (6%) had no signs of IHD. The in-hospital mortality of these three groups was 51%, 52%, and 27%, respectively...... (P = 0.01). Logistic regression analysis demonstrated that heart failure and cardiogenic shock were significant risk factors for in-hospital death among patients with IHD. Among discharged patients 1 and 5 years survival was 78% and 51% for patients with MI, 63% and 25% for patients with IHD, 67...... with known IHD suffering in-hospital VF without AMI have a very poor short- and long-term prognosis. These patients need extensive cardiac examination....

  4. Advances in Imaging for Atrial Fibrillation Ablation

    International Nuclear Information System (INIS)

    D'Silva, A.; Wright, M.; Wright, M.

    2011-01-01

    Over the last fifteen years, our understanding of the pathophysiology of atrial fibrillation (AF) has paved the way for ablation to be utilized as an effective treatment option. With the aim of gaining more detailed anatomical representation, advances have been made using various imaging modalities, both before and during the ablation procedure, in planning and execution. Options have flourished from procedural fluoroscopy, electro anatomic mapping systems, pre procedural computed tomography (CT), magnetic resonance imaging (MRI), ultrasound, and combinations of these technologies. Exciting work is underway in an effort to allow the electro physiologist to assess scar formation in real time. One advantage would be to lessen the learning curve for what are very complex procedures. The hope of these developments is to improve the likelihood of a successful ablation procedure and to allow more patients access to this treatment

  5. Pathogenic Mechanisms of Atrial Fibrillation in Obesity

    Directory of Open Access Journals (Sweden)

    O. M. Drapkina

    2016-01-01

    Full Text Available Atrial fibrillation (AF is one of the most common arrhythmias. It reduces quality of life and its duration due to thromboembolic complications. Obesity contributes to the structural and electrical remodeling of atrial myocardium. This leads to occurrence of ectopic foci in the mouths of the pulmonary veins and the disruption of normal electrical conduction in the atria. Systemic inflammation, myocardial fibrosis, cardiomyocyte overload by Na+ and Ca2+ ions, accumulation in the cells of unoxidized metabolic products, imbalance of the autonomic regulation are considered as the main mechanisms of arrhythmogenic substrate formation. Hypertension, insulin resistance, and obstructive sleep apnea, associated with obesity, increase the risk of development and progression of the arrhythmia. Study of pathogenetic mechanisms of AF in obesity is necessary to develop new strategies for its prevention and the creation of more effective methods of treatment of these patients.

  6. Ventricular fibrillation after accidental injection of bupivacaine into the pericardium

    NARCIS (Netherlands)

    Even, B. J.; de Jongh, R. F.; de Hert, S. G.

    1992-01-01

    A postoperative cardiac surgical patient developed ventricular fibrillation immediately after accidental pericardial injection of bupivacaine at room temperature. The possible causes, which include systemic toxicity, local vasoconstriction with myocardial ischaemia, local toxic effect of bupivacaine

  7. Dronedarone in high-risk permanent atrial fibrillation

    DEFF Research Database (Denmark)

    Connolly, Stuart J; Camm, A John; Halperin, Jonathan L

    2011-01-01

    Dronedarone restores sinus rhythm and reduces hospitalization or death in intermittent atrial fibrillation. It also lowers heart rate and blood pressure and has antiadrenergic and potential ventricular antiarrhythmic effects. We hypothesized that dronedarone would reduce major vascular events...

  8. Stroke and bleeding in atrial fibrillation with chronic kidney disease

    DEFF Research Database (Denmark)

    Olesen, Jonas Bjerring; Lip, Gregory Y.H.; Kamper, Anne-Lise

    2012-01-01

    Both atrial fibrillation and chronic kidney disease increase the risk of stroke and systemic thromboembolism. However, these risks, and the effects of antithrombotic treatment, have not been thoroughly investigated in patients with both conditions....

  9. Dronedarone in high-risk permanent atrial fibrillation

    DEFF Research Database (Denmark)

    Connolly, Stuart J; Camm, A John; Halperin, Jonathan L

    2011-01-01

    Dronedarone restores sinus rhythm and reduces hospitalization or death in intermittent atrial fibrillation. It also lowers heart rate and blood pressure and has antiadrenergic and potential ventricular antiarrhythmic effects. We hypothesized that dronedarone would reduce major vascular events in ...

  10. Designing microcapsules based on protein fibrils and protein - polysaccharide complexes

    NARCIS (Netherlands)

    Hua, K.N.P.

    2012-01-01

    Keywords: encapsulation, microcapsule, protein, fibril, protein-polysaccharide complex, controlled release, interfacial rheology, lysozyme, ovalbumin This thesis describes the design of encapsulation systems using mesostructures from proteins and polysaccharides. The approach was to first

  11. Insulin fibrillation: The influence and coordination of Zn2+

    DEFF Research Database (Denmark)

    Frankær, Christian Grundahl; Sønderby, Pernille; Bang, Maria Blanner

    2017-01-01

    Protein amyloid fibrillation is obtaining much focus because it is connected with amyloid-related human diseases such as Alzheimer's disease, diabetes mellitus type 2, or Parkinson's disease. The influence of metal ions on the fibrillation process and whether it is implemented in the amyloid...... Electron Microscopy and Thioflavin T fluorescence measurements. It is well-known that Zn2+ ions coordinate and stabilize the hexameric forms of insulin. However, this study is the first to show that zinc indeed binds to the insulin fibrils. Furthermore, zinc influences the kinetics and the morphology...... of the fibrils. It also shows that zinc coordinates to histidine residues in an environment, which is similar to the coordination seen in the insulin R6 hexamers, where three histidine residues and a chloride ion is coordinating the zinc....

  12. Extraction of nanocellulose fibrils from lignocellulosic fibres: a novel approach

    CSIR Research Space (South Africa)

    Abraham, E

    2011-06-01

    Full Text Available The objective of this work was to develop a simple process to obtain an aqueous stable colloid suspension of cellulose nano fibrils from various lignocellulosic fibres. For the preliminary analysis we have studied three different fibres: banana...

  13. How curcumin affords effective protection against amyloid fibrillation in insulin?

    DEFF Research Database (Denmark)

    Rabiee, Atefeh; Ebrahim Habibi, Azadeh; Ghasemi, Atiyeh Ghasemi

    2013-01-01

    Since the formation of amyloid structures from proteins was recognized in numerous diseases, many efforts have been devoted to the task of finding effective anti-amyloidogenic compounds. In a number of these investigations, the existence of “generic” compounds is implicitly acknowledged. Curcumin...... been shown effectively influenced by micro molar concentrations of curcumin. Under amyloidogenic conditions (pH 2.5 and 37°C), the compound was observed to inhibit fibril formation of insulin in a dose-dependent manner. Moreover, addition of curcumin to the protein incubated in such conditions...... at different time points resulted in reduced amounts of final fibrils. Disaggregation of pre-formed fibrils was also observed upon addition of curcumin, as well as reduction in final fibril amounts after seeding. Overall, this compound appears to be able to interact with native, intermediate and fibrillar...

  14. Analysis of amyloid fibrils in the cheetah (Acinonyx jubatus).

    Science.gov (United States)

    Bergström, Joakim; Ueda, Mitsuharu; Une, Yumi; Sun, Xuguo; Misumi, Shogo; Shoji, Shozo; Ando, Yukio

    2006-06-01

    Recently, a high prevalence of amyloid A (AA) amyloidosis has been documented among captive cheetahs worldwide. Biochemical analysis of amyloid fibrils extracted from the liver of a Japanese captive cheetah unequivocally showed that protein AA was the main fibril constituent. Further characterization of the AA fibril components by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) and Western blot analysis revealed three main protein AA bands with approximate molecular weights of 8, 10 and 12 kDa. Mass spectrometry analysis of the 12-kDa component observed in SDS-PAGE and Western blotting confirmed the molecular weight of a 12,381-Da peak. Our finding of a 12-kDa protein AA component provides evidence that the cheetah SAA sequence is longer than the previously reported 90 amino acid residues (approximately 10 kDa), and hence SAA is part of the amyloid fibril.

  15. Does perceived stress increase the risk of atrial fibrillation?

    DEFF Research Database (Denmark)

    Graff, Simon; Prior, Anders; Fenger-Grøn, Morten

    2017-01-01

    Background Psychological stress is associated with increased risk of acute cardiovascular diseases, as myocardial infarction. We recently found a higher risk of atrial fibrillation following an acute stressful life event, but it remains unknown whether this also applies to common and less acute...... stress exposures. Methods We investigated the risk of incident atrial fibrillation in people with high levels of perceived stress by following a population-based cohort of 114,337 participants from the Danish National Health Survey from 2010 to 2014. The survey holds information on lifestyle factors......-up. The hazard ratio (HR) of atrial fibrillation with 95% confidence interval (CI) was calculated with Cox proportional hazard model. Results The risk of atrial fibrillation increased with increasing PSS score; persons in the highest perceived stress quintile had 28% (95% CI, 12%-46%) higher risk of atrial...

  16. Stroke prevention strategies in North American patients with atrial fibrillation

    DEFF Research Database (Denmark)

    McIntyre, William F; Conen, David; Olshansky, Brian

    2018-01-01

    BACKGROUND: Antithrombotic prophylaxis with oral anticoagulation (OAC) substantially reduces stroke and mortality in patients with atrial fibrillation (AF). HYPOTHESIS: Analysis of data in GLORIA-AF, an international, observational registry of patients with newly-diagnosed AF, can identify factor...

  17. Atrioverter : An implantable device for the treatment of atrial fibrillation

    NARCIS (Netherlands)

    Wellens, HJJ; Lau, CP; Luderitz, B; Akhtar, M; Waldo, AL; Camm, AJ; Timmermans, C; Tse, HF; Jung, W; Jordaens, L; Ayers, G

    1998-01-01

    Background-During atrial fibrillation, electrophysiological changes occur in atrial tissue that favor the maintenance of the arrhythmia and facilitate recurrence after conversion to sinus rhythm. An implantable defibrillator connected to right atrial and coronary sinus defibrillation leads allows

  18. Imaging of Ventricular Fibrillation and Defibrillation: The Virtual Electrode Hypothesis.

    Science.gov (United States)

    Boukens, Bastiaan J; Gutbrod, Sarah R; Efimov, Igor R

    2015-01-01

    Ventricular fibrillation is the major underlying cause of sudden cardiac death. Understanding the complex activation patterns that give rise to ventricular fibrillation requires high resolution mapping of localized activation. The use of multi-electrode mapping unraveled re-entrant activation patterns that underlie ventricular fibrillation. However, optical mapping contributed critically to understanding the mechanism of defibrillation, where multi-electrode recordings could not measure activation patterns during and immediately after a shock. In addition, optical mapping visualizes the virtual electrodes that are generated during stimulation and defibrillation pulses, which contributed to the formulation of the virtual electrode hypothesis. The generation of virtual electrode induced phase singularities during defibrillation is arrhythmogenic and may lead to the induction of fibrillation subsequent to defibrillation. Defibrillating with low energy may circumvent this problem. Therefore, the current challenge is to use the knowledge provided by optical mapping to develop a low energy approach of defibrillation, which may lead to more successful defibrillation.

  19. Uninterrupted Dabigatran versus Warfarin for Ablation in Atrial Fibrillation

    NARCIS (Netherlands)

    Calkins, Hugh; Willems, Stephan; Gerstenfeld, Edward P.; Verma, Atul; Schilling, Richard; Hohnloser, Stefan H.; Okumura, Ken; Serota, Harvey; Nordaby, Matias; Guiver, Kelly; Biss, Branislav; Brouwer, Marc A.; Grimaldi, Massimo; de Asmundis, Carlo; Debruyne, Philippe; Pierard, Luc; Scavé e, Christophe; Schwagten, Bruno; van Acker, Hannes; van Heuverswyn, Frank; Ayala-Paredes, Felix; Lane, Christopher; Lockwood, Evan; Michael, Kevin; Morillo, Carlos; O’ Hara, Gilles; Cebron, Jean-Pierre; Chevalier, Philippe; DeChillou, Christian; Defaye, Pascal; Deharo, Jean-Claude; Duthoit, Guillaume; Marijon, Eloi; Mechulan, Alexis; Sacher, Fré dé ric; Bonnemeier, Hendrik; Dahme, Tillmann; Ince, H.ü seyin; Neumann, Thomas; Steven, Daniel; Ü cer, Ekrem; Zabel, Markus; Calo, Leonardo; Cireddu, Manuela; Menardi, Endrju; Themistoclakis, Sakis; Tondo, Claudio; Fujii, Kenshi; Iwasa, Atsushi; Inden, Yasuya; Kimura, Masaomi; Murakami, Masato; Murakami, Yoshimasa; Satomi, Kazuhiro; Shimizu, Wataru; Watarai, Masato; Yoshida, Yukihiko; Merino, José -Luí s; Mitjans, Angel Moya; Mont, Lluí s; Asensi, Joaquí n Osca; Pedrote Martí nez, Á ngel Alonso; Teijeira-Ferná ndez, Elvis; Allaart, Cornelis P.; de Jong, Jonas S. G.; Folkeringa, Richard J.; Simmers, Tim A.; Barbarash, Olga L.; Kuznetsov, Vadim; Nedoshivin, Aleksandr; Novikova, Tatiana; Revishvili, Amiran S.; Staroverov, Ilya; Agarwal, Sharad; Betts, Timothy; Connelly, Derek; Hobson, Neil; Leong, Fong; McCready, James; Paisey, John; Tayebjee, Muzahir; Thornley, Andrew; Ahmed, Jameel; Beck, Hiroko; Beinart, Sean; Bindra, Sanjay; Chae, Sanders; Cheng, Jie; Eldadah, Zayd; Feigenblum, David; Fuenzalida, Charles; Gandhavadi, Maheer; Garabelli, Paul; Gerstenfeld, Edward; Gonzalez, Mario; Hurwitz, Jodie; Johnson, Colleen; Kabra, Rajesh; Kowalski, Marcin; Kulkarni, Gurudutt; Marrouche, Nassir; Miller, John; Mounsey, Paul; Norris, Blake; O’ Neill, Gearoid; Roukoz, Henri; Srivatsa, Uma; Talano, James; Vora, Aaditya; Wong, Brian; Camm, John; Cappato, Riccardo; Crijns, Harry; Kenigsberg, David; Tijssen, Jan G. P.; Januzzi, James; Garasic, Joe; Pehrson, Steen; Kolansky, Daniel; McDonald, Michael; van Tosh, Andrew; Sturm, Jonathan; Peeters, André ; Hirsch, Karen

    2017-01-01

    BACKGROUND Catheter ablation of atrial fibrillation is typically performed with uninterrupted anticoagulation with warfarin or interrupted non-vitamin K antagonist oral anticoagulant therapy. Uninterrupted anticoagulation with a non-vitamin K antagonist oral anticoagulant, such as dabigatran, may be

  20. Women Sex Importance in Stroke Patients with Atrial Fibrillation

    Directory of Open Access Journals (Sweden)

    Cemile Handan Mısırlı

    2014-08-01

    Full Text Available OBJECTIVE: It was shown the differences in age, risk factors and treatment between women and men in stroke patients with atrial fibrillation METHODS: The stroke patients with atrial fibrillation who were hospitalized in our department at the last 2 years were seperated into 2 groups of aged above 75 and below 75, investigated with CHADS2 and CHA2DS2VASc scores and looked at the sex differences of women and men. RESULTS: Stroke ratio according to sex was statistically meaningful especially in women above the age of 75. Risc factors also were founded in elderly women and CHA2DS2VASc scores were higher in women than men so more anticoagulan treatment were begun. No differences were shown between sexes at lone atrial fibrillation and no treatment were begun. CONCLUSION: Women with atrial fibrillation had more risk factors, higher stroke rate and higher anticoagulation treatment.

  1. Designing microcapsules based on protein fibrils and protein - polysaccharide complexes

    NARCIS (Netherlands)

    Hua, K.N.P.

    2012-01-01

    Keywords: encapsulation, microcapsule, protein, fibril, protein-polysaccharide complex, controlled release, interfacial rheology, lysozyme, ovalbumin

    This thesis describes the design of encapsulation systems using mesostructures from proteins and polysaccharides. The approach

  2. YKL-40 levels and atrial fibrillation in the general population

    DEFF Research Database (Denmark)

    Marott, Sarah C W; Benn, Marianne; Johansen, Julia S

    2013-01-01

    BACKGROUND: Atrial fibrillation is associated with inflammation. In contrast to inflammatory markers like C-reactive protein (CRP) and fibrinogen produced in the liver, YKL-40 is produced at the site of inflammation including in the myocardium. We hypothesized that elevated plasma YKL-40 levels a...... individuals from the cross-sectional Copenhagen General Population Study including 337 cases with atrial fibrillation. A YKL-40 level >95% percentile (>204μg/L) versus 95% percentile versus...

  3. [Risk and benefit of oral anticoagulants in atrial fibrillation].

    Science.gov (United States)

    Zotova, I V; Zateĭshchikov, D A

    2011-01-01

    Thromboembolism is the main cause of death and disability of patients with atrial fibrillation. Indirect anticoagulants are effective means of primary and secondary prevention of thromboembolic complications. However in a number of patients risk associated with therapy with indirect anticoagulants might exceed potential benefit. The principle problem requiring solution in a patient with atrial fibrillation is individual comparative assessment of risk of development of thromboembolic and hemorrhagic complications. Modern stratification scales which allow solving this problem are considered in this review.

  4. Echocardiographic quantification of systolic function during atrial fibrillation

    DEFF Research Database (Denmark)

    Olsen, Flemming Javier; Jørgensen, Peter Godsk; Dons, Maria

    2016-01-01

    It is often difficult to provide an exact echocardiographic measure of left ventricular systolic function in patients with atrial fibrillation, partly because of the varying cycle length affecting pre and afterload and partly because of the increased heart rate often accompanying this arrhythmia....... We sought to elucidate two points: whether it would be possible to correct for the cyclic variance in systolic output, and if global longitudinal strain is preferable to the left ventricular ejection fraction at evaluating systolic function during atrial fibrillation....

  5. Catheter Ablation for Long-Standing Persistent Atrial Fibrillation

    OpenAIRE

    Romero, Jorge; Gianni, Carola; Di Biase, Luigi; Natale, Andrea

    2015-01-01

    Atrial fibrillation (AF) is the most common sustained arrhythmia worldwide and represents a major burden to health care systems. Atrial fibrillation is associated with a 4- to 5-fold increased risk of thromboembolic stroke. The pulmonary veins have been identified as major sources of atrial triggers for AF. This is particularly true in patients with paroxysmal AF but not always the case for those with long-standing persistent AF (LSPAF), in which other locations for ectopic beats have been we...

  6. Modeling of STATCOM under different loading conditions

    DEFF Research Database (Denmark)

    George, G.J.; Ramachandran, Rakesh; Kowsalya, M.

    2012-01-01

    This paper deals with the study and analysis of Flexible AC Transmission Systems (FACTS), mainly the modeling of STATCOM. Reactive Power Compensation plays a very important role in the transmission of Electric Power. A comparative study of how the reactive power is injected into the transmission ...... system with and without STATCOM under different loading condition is also illustrated in this paper. Simulations are performed using MATLAB/SIMULINK software....

  7. Viologen-Phosphorus Dendrimers Inhibit α-Synuclein Fibrillation.

    Science.gov (United States)

    Milowska, Katarzyna; Grochowina, Justyna; Katir, Nadia; El Kadib, Abdelkrim; Majoral, Jean-Pierre; Bryszewska, Maria; Gabryelak, Teresa

    2013-03-04

    Inhibition of α-synuclein (ASN) fibril formation is a potential therapeutic strategy in Parkinson's disease and other synucleinopathies. The aim of this study was to examine the role of viologen-phosphorus dendrimers in the α-synuclein fibrillation process and to assess the structural changes in α-synuclein under the influence of dendrimers. ASN interactions with phosphonate and pegylated surface-reactive viologen-phosphorus dendrimers were examined by measuring the zeta potential, which allowed determining the number of dendrimer molecules that bind to the ASN molecule. The fibrillation kinetics and the structural changes were examined using ThT fluorescence and CD spectroscopy. Depending on the concentration of the used dendrimer and the nature of the reactive groups located on the surface, ASN fibrillation kinetics can be significantly reduced, and even, in the specific case of phosphonate dendrimers, the fibrillation can be totally inhibited at low concentrations. The presented results indicate that viologen-phosphorus dendrimers are able to inhibit ASN fibril formation and may be used as fibrillar regulating agents in neurodegenerative disorders.

  8. Fibrillization kinetics of insulin solution in an interfacial shearing flow

    Science.gov (United States)

    Balaraj, Vignesh; McBride, Samantha; Hirsa, Amir; Lopez, Juan

    2015-11-01

    Although the association of fibril plaques with neurodegenerative diseases like Alzheimer's and Parkinson's is well established, in-depth understanding of the roles played by various physical factors in seeding and growth of fibrils is far from well known. Of the numerous factors affecting this complex phenomenon, the effect of fluid flow and shear at interfaces is paramount as it is ubiquitous and the most varying factor in vivo. Many amyloidogenic proteins have been found to denature upon contact at hydrophobic interfaces due to the self-assembling nature of protein in its monomeric state. Here, fibrillization kinetics of insulin solution is studied in an interfacial shearing flow. The transient surface rheological response of the insulin solution to the flow and its effect on the bulk fibrillization process has been quantified. Minute differences in hydrophobic characteristics between two variants of insulin- Human recombinant and Bovine insulin are found to result in very different responses. Results presented will be in the form of fibrillization assays, images of fibril plaques formed, and changes in surface rheological properties of the insulin solution. The interfacial velocity field, measured from images (via Brewster Angle Microscopy), is compared with computations. Supported by NNX13AQ22G, National Aeronautics and Space Administration.

  9. Atrial fibrillation patients do not benefit from acetylsalicylic acid.

    Science.gov (United States)

    Själander, Sara; Själander, Anders; Svensson, Peter J; Friberg, Leif

    2014-05-01

    Oral anticoagulation is the recommended treatment for stroke prevention in patients with atrial fibrillation. Notwithstanding, many patients are treated with acetylsalicylic acid (ASA) as monotherapy. Our objective was to investigate if atrial fibrillation patients benefit from ASA as monotherapy for stroke prevention. Retrospective study of patients with a clinical diagnosis of atrial fibrillation between 1 July 2005 and 1 January 2009 in the National Swedish Patient register, matched with data from the National Prescribed Drugs register. Endpoints were ischaemic stroke, thrombo-embolic event, intracranial haemorrhage, and major bleeding. The study population consisted of 115 185 patients with atrial fibrillation, of whom 58 671 were treated with ASA as monotherapy and 56 514 were without any antithrombotic treatment at baseline. Mean follow-up was 1.5 years. Treatment with ASA was associated with higher risk of ischaemic stroke and thrombo-embolic events compared with no antithrombotic treatment. Acetylsalicylic acid as monotherapy in stroke prevention of atrial fibrillation has no discernable protective effect against stroke, and may even increase the risk of ischaemic stroke in elderly patients. Thus, our data support the new European guidelines recommendation that ASA as monotherapy should not be used as stroke prevention in atrial fibrillation.

  10. Ellagic acid promotes Aβ42 fibrillization and inhibits Aβ42-induced neurotoxicity

    International Nuclear Information System (INIS)

    Feng, Ying; Yang, Shi-gao; Du, Xue-ting; Zhang, Xi; Sun, Xiao-xia; Zhao, Min; Sun, Gui-yuan; Liu, Rui-tian

    2009-01-01

    Smaller, soluble oligomers of β-amyloid (Aβ) play a critical role in the pathogenesis of Alzheimer's disease (AD). Selective inhibition of Aβ oligomer formation provides an optimum target for AD therapy. Some polyphenols have potent anti-amyloidogenic activities and protect against Aβ neurotoxicity. Here, we tested the effects of ellagic acid (EA), a polyphenolic compound, on Aβ42 aggregation and neurotoxicity in vitro. EA promoted Aβ fibril formation and significant oligomer loss, contrary to previous results that polyphenols inhibited Aβ aggregation. The results of transmission electron microscopy (TEM) and Western blot displayed more fibrils in Aβ42 samples co-incubated with EA in earlier phases of aggregation. Consistent with the hypothesis that plaque formation may represent a protective mechanism in which the body sequesters toxic Aβ aggregates to render them harmless, our MTT results showed that EA could significantly reduce Aβ42-induced neurotoxicity toward SH-SY5Y cells. Taken together, our results suggest that EA, an active ingredient in many fruits and nuts, may have therapeutic potential in AD.

  11. Ellagic acid promotes A{beta}42 fibrillization and inhibits A{beta}42-induced neurotoxicity

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Ying [Department of Histology and Embryology, College of Basic Medical Science, China Medical University, Shenyang 110001 (China); Tsinghua University School of Medicine, Haidian District, Beijing 100084 (China); Yang, Shi-gao; Du, Xue-ting; Zhang, Xi; Sun, Xiao-xia; Zhao, Min [Tsinghua University School of Medicine, Haidian District, Beijing 100084 (China); Sun, Gui-yuan, E-mail: sungy2004@sohu.com [Department of Histology and Embryology, College of Basic Medical Science, China Medical University, Shenyang 110001 (China); Liu, Rui-tian, E-mail: rtliu@tsinghua.edu.cn [Tsinghua University School of Medicine, Haidian District, Beijing 100084 (China)

    2009-12-25

    Smaller, soluble oligomers of {beta}-amyloid (A{beta}) play a critical role in the pathogenesis of Alzheimer's disease (AD). Selective inhibition of A{beta} oligomer formation provides an optimum target for AD therapy. Some polyphenols have potent anti-amyloidogenic activities and protect against A{beta} neurotoxicity. Here, we tested the effects of ellagic acid (EA), a polyphenolic compound, on A{beta}42 aggregation and neurotoxicity in vitro. EA promoted A{beta} fibril formation and significant oligomer loss, contrary to previous results that polyphenols inhibited A{beta} aggregation. The results of transmission electron microscopy (TEM) and Western blot displayed more fibrils in A{beta}42 samples co-incubated with EA in earlier phases of aggregation. Consistent with the hypothesis that plaque formation may represent a protective mechanism in which the body sequesters toxic A{beta} aggregates to render them harmless, our MTT results showed that EA could significantly reduce A{beta}42-induced neurotoxicity toward SH-SY5Y cells. Taken together, our results suggest that EA, an active ingredient in many fruits and nuts, may have therapeutic potential in AD.

  12. In vitro tendon tissue development from human fibroblasts demonstrates collagen fibril diameter growth associated with a rise in mechanical strength.

    Science.gov (United States)

    Herchenhan, Andreas; Bayer, Monika L; Svensson, René B; Magnusson, S Peter; Kjaer, Michael

    2013-01-01

    Collagen-rich tendons and ligaments are important for joint stability and force transmission, but the capacity to form new tendon is poorly understood. In the present study, we investigated mechanical strength, fibril size, and structure during development of tendon-like tissue from adult human tenocytes (termed tendon constructs) in vitro over 5 weeks in 3D tissue culture. The constructs displayed large elongated tendon cells aligned along the tendon axis together with collagen fibrils that increased in diameter by 50% from day 14 to 35, which approaches that observed in adult human tendon in vivo. The increase in diameter was accompanied by a 5-fold increase in mechanical strength (0.9±0.1 MPa to 4.9±0.6 MPa) and Young's modulus (5.8±0.9 MPa to 32.3±4.2 MPa), while the maximal strain at failure (16%) remained constant throughout the 5-week culture period. The present study demonstrates that 3D tendon constructs can be formed by isolated human tendon fibroblasts, and when these constructs are subjected to static self-generated tension, the fibrils will grow in size and strength approaching that of adult human tendon in vivo. Copyright © 2012 Wiley Periodicals, Inc.

  13. Dark-field transmission electron microscopy of cortical bone reveals details of extrafibrillar crystals.

    Science.gov (United States)

    Schwarcz, Henry P; McNally, Elizabeth A; Botton, Gianluigi A

    2014-12-01

    In a previous study we showed that most of the mineral in bone is present in the form of "mineral structures", 5-6nm-thick, elongated plates which surround and are oriented parallel to collagen fibrils. Using dark-field transmission electron microscopy, we viewed mineral structures in ion-milled sections of cortical human bone cut parallel to the collagen fibrils. Within the mineral structures we observe single crystals of apatite averaging 5.8±2.7nm in width and 28±19nm in length, their long axes oriented parallel to the fibril axis. Some appear to be composite, co-aligned crystals as thin as 2nm. From their similarity to TEM images of crystals liberated from deproteinated bone we infer that we are viewing sections through platy crystals of apatite that are assembled together to form the mineral structures. Copyright © 2014 Elsevier Inc. All rights reserved.

  14. Automatic Detection of Atrial Fibrillation Using Basic Shannon Entropy of RR Interval Feature

    Science.gov (United States)

    Afdala, Adfal; Nuryani, Nuryani; Satriyo Nugroho, Anto

    2017-01-01

    Atrial Fibrillation is one of heart disease, that common characterized by irregularity heart beat. Atrial fibrillation leads to severe complications such as cardiac failure with the subsequent risk of a stroke. A method to detect atrial fibrillation is needed to prevent a risk of atrial fibrillation. This research uses data from physionet in atrial fibrillation database category. The performance of Shannon entropy has the highest accuracy if a threshold is 0.5 with accuracy 89.79%, sensitivity 91.04% and specificity 89.01%. Based on the result we get a conclusion, the ability of Shannon entropy to detect atrial fibrillation is good.

  15. Transmission infrastructure development in Alberta

    Energy Technology Data Exchange (ETDEWEB)

    Stubbings, R.V. [EnVision Energy Consulting Ltd., Calgary, AB (Canada)

    2004-09-01

    Major power blackouts have resulted in greater attention to reliability. Changes in industry structure have placed unanticipated demands on transmission systems. Load growth has outstripped transmission investment, and there are major implications for infrastructure development due to the enactment of the new transmission regulation. This paper discusses several projects addressing new developments in the electric power industry, including details of an Edmonton-Calgary path upgrade in order to increase north-south transmission capacity. Proposed southwest Transmission upgrades were reviewed, including the construction of a double-circuit 240 kV line from Pincher Creek to Peigan or Mud Lake, in order to improve reliability and improve access to southern wind and hydro generation. Other possible projects include a High Voltage Direct Current (HVDC) from Fort McMurray to Calgary and a Northern Lights Transmission project between Fort McMurray and the Pacific Northwest. Various investment drivers were reviewed, with oil sands processing providing steam hosts for cogeneration at Fort McMurray and Cold Lake generation as well as Lake Wabamun. Plans concerning Southwest Alberta generation were presented, including wind-powered generation, and load growth in southern Alberta. Various investment limiters include absorption of existing capacity; improved facility utilization; and distributed generation. Competition for investment funds were discussed, in addition to uncertainties over generation siting as well as regulatory difficulties and power flow pattern irregularities due to increasing market integration. Uncertain access to markets, locational marginal pricing and various southern Alberta generation incentives were reviewed. Market implications include generation mix; lower price volatility; reduced potential for market power abuse by generators; and increased export levels. The implications for British Columbia were highlighted, with particular reference to an

  16. Physicochemical characteristics and fibril-forming properties of collagen from paddlefish (Polyodon spathula and globefish (Fugu flavidus skin byproducts

    Directory of Open Access Journals (Sweden)

    Shanshan WANG

    Full Text Available Abstract Acid-soluble collagen (ASC and pepsin-soluble collagen (PSC from the skin byproducts of paddlefish (ASC-P and PSC-P and globefish (ASC-G and PSC-G were purified and characterized. The imino acid contents of ASC-P, PSC-P, ASC-G and PSC-G were 194.1, 197.9, 186.4 and 189.7 residues/1000 residues, respectively. SDS-polyacrylamide gel electrophoresis (SDS-PAGE and Fourier transform infrared spectroscopy (FTIR confirmed that all four samples composed of two different α1- and α2-chains with integrated triple-helical structure. Denaturation temperatures of ASC-P, PSC-P, ASC-G and PSC-G were 29.6, 28.2, 27.4 and 26.9 °C, respectively. Based on Transmission electron microscopy (TEM observation, all four samples could assemble into fibrils in vitro with D-periodicity. However, the fibril-forming rate of ASC-P and PSC-P was more rapid than that of ASC-G and PSC-G. Scanning electron microscopy (SEM analysis confirmed well-defined fibril morphologies,the diameter of fibrils from ASC-P and PSC-P was thicker than those of ASC-G and PSC-G after 24 h incubation. These results indicated that paddlefish and globefish skin collagens could be alternatives to terrestrial collagens for applications in food-packaging, nutraceutical and pharmaceutical industries.

  17. HIV transmission. Selection bias at the heterosexual HIV-1 transmission bottleneck.

    Science.gov (United States)

    Carlson, Jonathan M; Schaefer, Malinda; Monaco, Daniela C; Batorsky, Rebecca; Claiborne, Daniel T; Prince, Jessica; Deymier, Martin J; Ende, Zachary S; Klatt, Nichole R; DeZiel, Charles E; Lin, Tien-Ho; Peng, Jian; Seese, Aaron M; Shapiro, Roger; Frater, John; Ndung'u, Thumbi; Tang, Jianming; Goepfert, Paul; Gilmour, Jill; Price, Matt A; Kilembe, William; Heckerman, David; Goulder, Philip J R; Allen, Todd M; Allen, Susan; Hunter, Eric

    2014-07-11

    Heterosexual transmission of HIV-1 typically results in one genetic variant establishing systemic infection. We compared, for 137 linked transmission pairs, the amino acid sequences encoded by non-envelope genes of viruses in both partners and demonstrate a selection bias for transmission of residues that are predicted to confer increased in vivo fitness on viruses in the newly infected, immunologically naïve recipient. Although tempered by transmission risk factors, such as donor viral load, genital inflammation, and recipient gender, this selection bias provides an overall transmission advantage for viral quasispecies that are dominated by viruses with high in vivo fitness. Thus, preventative or therapeutic approaches that even marginally reduce viral fitness may lower the overall transmission rates and offer long-term benefits even upon successful transmission. Copyright © 2014, American Association for the Advancement of Science.

  18. Modeling an in-register, parallel "iowa" aβ fibril structure using solid-state NMR data from labeled samples with rosetta.

    Science.gov (United States)

    Sgourakis, Nikolaos G; Yau, Wai-Ming; Qiang, Wei

    2015-01-06

    Determining the structures of amyloid fibrils is an important first step toward understanding the molecular basis of neurodegenerative diseases. For β-amyloid (Aβ) fibrils, conventional solid-state NMR structure determination using uniform labeling is limited by extensive peak overlap. We describe the characterization of a distinct structural polymorph of Aβ using solid-state NMR, transmission electron microscopy (TEM), and Rosetta model building. First, the overall fibril arrangement is established using mass-per-length measurements from TEM. Then, the fibril backbone arrangement, stacking registry, and "steric zipper" core interactions are determined using a number of solid-state NMR techniques on sparsely (13)C-labeled samples. Finally, we perform Rosetta structure calculations with an explicitly symmetric representation of the system. We demonstrate the power of the hybrid Rosetta/NMR approach by modeling the in-register, parallel "Iowa" mutant (D23N) at high resolution (1.2Å backbone rmsd). The final models are validated using an independent set of NMR experiments that confirm key features. Copyright © 2015 Elsevier Ltd. All rights reserved.

  19. Efficient Load Scheduling Method For Power Management

    Directory of Open Access Journals (Sweden)

    Vijo M Joy

    2015-08-01

    Full Text Available An efficient load scheduling method to meet varying power supply needs is presented in this paper. At peak load times the power generation system fails due to its instability. Traditionally we use load shedding process. In load shedding process disconnect the unnecessary and extra loads. The proposed method overcomes this problem by scheduling the load based on the requirement. Artificial neural networks are used for this optimal load scheduling process. For generate economic scheduling artificial neural network has been used because generation of power from each source is economically different. In this the total load required is the inputs of this network and the power generation from each source and power losses at the time of transmission are the output of the neural network. Training and programming of the artificial neural networks are done using MATLAB.

  20. Papain-gel Degrades Intact Nonmineralized Type I Collagen Fibrils

    Science.gov (United States)

    BERTASSONI, L. E.; MARSHALL, G. W.

    2010-01-01

    Summary Papain-gel has been utilized as a chemomechanical material for caries removal due to its ability to preserve underlying sound dentin. However, little is known about the effect of the papain enzyme on intact type I collagen fibrils that compose the dentin matrix. Here we sought to define structural changes that occur in intact type I collagen fibrils after an enzymatic treatment with a papaingel. Intact and nonmineralized type I collagen fibrils from rat tail were obtained and treated with a papain-gel (Papacarie) for 30 s, rinsed with water and imaged using an atomic force microscope (AFM). Additionally, polished healthy dentin specimens were also treated using the same protocol described above and had their elastic modulus (E) and hardness (H) measured by means of AFM-based nanoindentation. AFM images showed that the papain-gel induced partial degradation of the fibrils surface, yet no rupture of fibrils was noticed. The distinction between gap and overlap zones of fibrils vanished in most regions after treatment, and overlap zones appeared to be generally more affected. Mechanical data suggested a gradual decrease in E and H after treatments. A significant two-fold drop from the values of normal dentin (E= 20 +/− 1.9, H = 0.8 +/− 0.08 GPa) was found after four applications (E = 9.7 +/− 3.2, H = 0.24 +/− 0.1 GPa) ( P<0.001), which may be attributed to the degradation of proteoglycans of the matrix. In summary, this study provided novel evidence that intact nonmineralized type I collagen fibrils are partially degraded by a papain-gel. PMID:20205185

  1. Screening for atrial fibrillation in Canadian pharmacies: an economic evaluation.

    Science.gov (United States)

    Tarride, Jean-Eric; Dolovich, Lisa; Blackhouse, Gordon; Guertin, Jason Robert; Burke, Natasha; Manja, Veena; Grinvalds, Alex; Lim, Ting; Healey, Jeff S; Sandhu, Roopinder K

    2017-08-22

    Screening for undiagnosed atrial fibrillation may lead to treatment with oral anticoagulation therapy, which can decrease the risk of ischemic stroke. The objective of this study was to conduct an economic evaluation of the Program for the Identification of 'Actionable' Atrial Fibrillation in the Pharmacy Setting (PIAAF-Pharmacy), which screened 1145 participants aged 65 years or more at 30 community pharmacies in Ontario and Alberta between October 2014 and April 2015. We used a 2-part decision model to evaluate the short- and long-term costs and quality-adjusted life-years (QALYs) of a pharmacy screening program for atrial fibrillation compared to no screening. Data from the PIAAF-Pharmacy study were used for the short-term model, and the relevant literature was used to extrapolate the benefits of the PIAAF-Pharmacy study in the long-term model. Costs and QALYs were calculated from a payer perspective over a lifetime horizon and were discounted at 1.5%/year. Screening for atrial fibrillation in pharmacies was associated with higher costs ($26) and more QALYs (0.0035) compared to no screening, yielding an incremental cost per QALY gained of $7480. Univariate and probabilistic sensitivity analyses confirmed that screening for atrial fibrillation in a pharmacy setting was a cost-effective strategy. Our results support screening for atrial fibrillation in Canadian pharmacies. Given this finding, efforts should be made by provincial governments and pharmacies to implement such programs in Canada. The addition of atrial fibrillation screening alongside screening and management of other cardiovascular conditions may help to reduce the burden of stroke. Copyright 2017, Joule Inc. or its licensors.

  2. Wool fibril sponges with perspective biomedical applications

    Energy Technology Data Exchange (ETDEWEB)

    Patrucco, A., E-mail: a.patrucco@bi.ismac.cnr.it [CNR-ISMAC, Italian National Research Council, Institute for Macromolecular Studies, Corso G. Pella 16, 13900, Biella (Italy); Cristofaro, F., E-mail: francesco.cristofaro01@universitadipavia.it [Department of Molecular Medicine, INSTM UdR of Pavia, University of Pavia, Viale Taramelli 3/B, 27100, Pavia (Italy); Centre for Health Technologies (CHT), University of Pavia, Via Ferrata 1, 27100, Pavia (Italy); Simionati, M., E-mail: m.simionati@bi.ismac.cnr.it [CNR-ISMAC, Italian National Research Council, Institute for Macromolecular Studies, Corso G. Pella 16, 13900, Biella (Italy); Zoccola, M., E-mail: m.zoccola@bi.ismac.cnr.it [CNR-ISMAC, Italian National Research Council, Institute for Macromolecular Studies, Corso G. Pella 16, 13900, Biella (Italy); Bruni, G., E-mail: giovanna.bruni@unipv.it [Department of Chemistry, — Physical-Chemistry Section, University of Pavia, Viale Taramelli 16, 27100, Pavia (Italy); Fassina, L., E-mail: lorenzo.fassina@unipv.it [Centre for Health Technologies (CHT), University of Pavia, Via Ferrata 1, 27100, Pavia (Italy); Department of Electrical, Computer and Biomedical Engineering, University of Pavia, Via Ferrata 1, 27100, Pavia (Italy); Visai, L., E-mail: livia.visai@unipv.it [Department of Molecular Medicine, INSTM UdR of Pavia, University of Pavia, Viale Taramelli 3/B, 27100, Pavia (Italy); Centre for Health Technologies (CHT), University of Pavia, Via Ferrata 1, 27100, Pavia (Italy); Department of Occupational Medicine, Toxicology and Environmental Risks, S. Maugeri Foundation, IRCCS, Via S. Boezio, 28, 27100, Pavia (Italy); Magenes, G., E-mail: giovanni.magenes@unipv.it [Centre for Health Technologies (CHT), University of Pavia, Via Ferrata 1, 27100, Pavia (Italy); Department of Electrical, Computer and Biomedical Engineering, University of Pavia, Via Ferrata 1, 27100, Pavia (Italy); and others

    2016-04-01

    Sheep's wool was used as a natural source to prepare keratin microfibril sponges for scaffolding, by disruption of the histological structure of the fibres through mild alkali treatment, followed by ultrasonication, casting and salt-leaching. The wool sponges showed highly interconnected porosity (93%) and contain intrinsic sites of cellular recognition that mimic the extracellular matrix (ECM). They displayed good thermal and water stability due to the conversion of disulphide cystine bonds into shorter monosulphide lanthionine intermolecular bonds, but significantly swelled in water, because of the high hydrophilicity and porosity, with a volume increasing up to 38%. Nevertheless, sponges were stable in water without structural changes, with a neutral pH in aqueous media, and showed excellent resilience to repeated compression stresses. According to in vitro biocompatibility assays, wool fibril sponges showed a good cell adhesion and proliferation as proved by MTT, FDA assays and SEM observations. The unique structure of the cortical cell network made by wool keratin proteins with controlled-size macro-porosity suitable for cell guesting, and nutrient feeding, provides an excellent scaffold for future tissue engineering applications. - Highlights: • Scaffolds were prepared from wool exploiting the fibres' histology structure. • The scaffold showed high interconnected micro- and macro-porosity. • The microscopic structure is very similar to the extracellular bone matrix. • Scaffolds reversibly swell in water with high resilience to repeated compression. • Composites were cytocompatible and supported the growth of SAOS-2 cell line.

  3. Cryptogenic stroke: atrial fibrillation under indictment

    Directory of Open Access Journals (Sweden)

    Marcella Jorfida

    2009-06-01

    Full Text Available The stroke is the third cause of death and the main cause of disability in adults. 30% of ischaemic strokes are cryptogenic. Atrial Fibrillation (AF is a common disease, mainly among older patients (pts (9% of people over 80. AF is an indipendent risk factor for stroke, and 15% of ischaemic strokes are due to AF (25% in older people. The cardioembolic risk is determinated by duration of AF and comorbilities: high risk pts are identified by risk score scales, in order to define who needs anticoagulation. Identification of pts with AF, symptomatic or not, is mandatory to prevent thromboembolism. Thrombo - embolic complications of asymptomatic AF (half of episodes are asymptomatic are similar to symptomatic. Accuracy of methods for AF detection is higher if the monitored period is long, in particular for detection of asymptomatic AF. A careful identification of asymptomatic AF is mandatory to indicate the anticoagulation therapy in people with thromboembolic risk factor: in particular, pts with a previous stroke need to detect carefully potential arrhythmias in order to avoid relapses.

  4. Atrial fibrillation and risk of stroke

    DEFF Research Database (Denmark)

    Christiansen, Christine Benn; Gerds, Thomas A.; Olesen, Jonas Bjerring

    2016-01-01

    AIM: Although the relation between stroke risk factors and stroke in patients with atrial fibrillation (AF) has been extensively examined, only few studies have explored the association of AF and the risk of ischaemic stroke/systemic thromboembolism/transient ischaemic attack (stroke....../TE/TIA) in the presence of concomitant stroke risk factors. METHODS AND RESULTS: From nationwide registries, all persons who turned 50, 60, 70, or 80 from 1997 to 2011 were identified. Persons receiving warfarin were excluded. The absolute risk of stroke/TE/TIA was reported for a 5-year period, as was the absolute risk...... ratios for AF vs. no AF according to prior stroke and the number of additional risk factors. The study cohort comprised of 3 076 355 persons without AF and 48 189 with AF. For men aged 50 years, with no risk factors, the 5-year risk of stroke was 1.1% (95% confidence interval 1.1-1.1); with AF alone 2...

  5. Postoperative atrial fibrillation in liver transplantation.

    Science.gov (United States)

    Xia, V W; Worapot, A; Huang, S; Dhillon, A; Gudzenko, V; Backon, A; Agopian, V G; Aksoy, O; Vorobiof, G; Busuttil, R W; Steadman, R H

    2015-03-01

    Postoperative atrial fibrillation (POAF) is common after major surgeries and is associated with increased morbidity and mortality. POAF after liver transplantation (LT) has not been reported. This study was undertaken to investigate the incidence, impact, and risk factors of POAF in LT patients. After IRB approval, LT between January 2006 and August 2013 at our center were retrospectively reviewed. POAF that occurred within 30 days after LT was included. Patients with and without POAF were compared and independent risk factors were identified by logistic regression. Of 1387 adults LT patients, 102 (7.4%) developed POAF during the study period. POAF was associated with significantly increased mortality, graft failure, acute kidney injury and prolonged hospital stay. Independent risk factors included age, body weight, MELD score, presence of previous history of AF, the vasopressors use prior to LT and pulmonary artery diastolic pressure at the end of LT surgery (odds ratios 2.0-7.2, all p < 0.05). A risk index of POAF was developed and patients with the high-risk index had more than 60% chance of developing POAF. These findings may be used to stratify patients and to guide prophylaxis for POAF in the posttransplant period. © Copyright 2015 The American Society of Transplantation and the American Society of Transplant Surgeons.

  6. Monitoring Atrial Fibrillation After Catheter Ablation.

    Science.gov (United States)

    Forleo, Giovanni B; Casella, Michela; Russo, Antonio Dello; Moltrasio, Massimo; Fassini, Gaetano; Tesauro, Manfredi; Tondo, Claudio

    2014-01-01

    Although catheter ablation is an effective treatment for recurrent atrial fibrillation (AF), there is no consensus on the definition of success or follow-up strategies. Symptoms are the major motivation for undergoing catheter ablation in patients with AF, however it is well known that reliance on perception of AF by patients after AF ablation results in an underestimation of recurrence of the arrhythmia. Because symptoms of AF occurrence may be misleading, a reliable assessment of rhythm outcome is essential for the definition of success in both clinical care and research trials. Continuous rhythm monitoring over long periods of time is superior to intermittent recording using external monitors to detect the presence of AF episodes and to quantify the AF burden. Today, new devices implanted subcutaneously using a minimally invasive technique have been developed for continuous AF monitoring. Implantable devices keep detailed information about arrhythmia recurrences and might allow identification of very brief episodes of AF, the significance of which is still uncertain. In particular, it is not known whether there is any critical value of daily AF burden that has a prognostic significance. This issue remains an area of active discussion, debate and investigation. Further investigation is required to determine if continuous AF monitoring with implantable devices is effective in reducing stroke risk and facilitating maintenance of sinus rhythm after AF ablation.

  7. Ventricular fibrillation time constant for swine

    International Nuclear Information System (INIS)

    Wu, Jiun-Yan; Sun, Hongyu; Nimunkar, Amit J; Webster, John G; O'Rourke, Ann; Huebner, Shane; Will, James A

    2008-01-01

    The strength–duration curve for cardiac excitation can be modeled by a parallel resistor–capacitor circuit that has a time constant. Experiments on six pigs were performed by delivering current from the X26 Taser dart at a distance from the heart to cause ventricular fibrillation (VF). The X26 Taser is an electromuscular incapacitation device (EMD), which generates about 50 kV and delivers a pulse train of about 15–19 pulses s −1 with a pulse duration of about 150 µs and peak current about 2 A. Similarly a continuous 60 Hz alternating current of the amplitude required to cause VF was delivered from the same distance. The average current and duration of the current pulse were estimated in both sets of experiments. The strength–duration equation was solved to yield an average time constant of 2.87 ms ± 1.90 (SD). Results obtained may help in the development of safety standards for future electromuscular incapacitation devices (EMDs) without requiring additional animal tests

  8. Red Wine, Resveratrol and Atrial Fibrillation.

    Science.gov (United States)

    Stephan, Laura Siga; Almeida, Eduardo Dytz; Markoski, Melissa Medeiros; Garavaglia, Juliano; Marcadenti, Aline

    2017-10-30

    Atrial fibrillation (AF) is a common cardiac arrhythmia that is associated with increased risk for cardiovascular disease and overall mortality. Excessive alcohol intake is a well-known risk factor for AF, but this correlation is less clear with light and moderate drinking. Besides, low doses of red wine may acutely prolong repolarization and slow cardiac conduction. Resveratrol, a bioactive polyphenol found in grapes and red wine, has been linked to antiarrhythmic properties and may act as an inhibitor of both intracellular calcium release and pathological signaling cascades in AF, eliminating calcium overload and preserving the cardiomyocyte contractile function. However, there are still no clinical trials at all that prove that resveratrol supplementation leads to improved outcomes. Besides, no observational study supports a beneficial effect of light or moderate alcohol intake and a lower risk of AF. The purpose of this review is to briefly describe possible beneficial effects of red wine and resveratrol in AF, and also present studies conducted in humans regarding chronic red wine consumption, resveratrol, and AF.

  9. Atrial fibrillation: effects beyond the atrium?

    Science.gov (United States)

    Wijesurendra, Rohan S; Casadei, Barbara

    2015-03-01

    Atrial fibrillation (AF) is the most common sustained clinical arrhythmia and is associated with significant morbidity, mostly secondary to heart failure and stroke, and an estimated two-fold increase in premature death. Efforts to increase our understanding of AF and its complications have focused on unravelling the mechanisms of electrical and structural remodelling of the atrial myocardium. Yet, it is increasingly recognized that AF is more than an atrial disease, being associated with systemic inflammation, endothelial dysfunction, and adverse effects on the structure and function of the left ventricular myocardium that may be prognostically important. Here, we review the molecular and in vivo evidence that underpins current knowledge regarding the effects of human or experimental AF on the ventricular myocardium. Potential mechanisms are explored including diffuse ventricular fibrosis, focal myocardial scarring, and impaired myocardial perfusion and perfusion reserve. The complex relationship between AF, systemic inflammation, as well as endothelial/microvascular dysfunction and the effects of AF on ventricular calcium handling and oxidative stress are also addressed. Finally, consideration is given to the clinical implications of these observations and concepts, with particular reference to rate vs. rhythm control. © The Author 2015. Published by Oxford University Press on behalf of the European Society of Cardiology.

  10. Imaging in percutaneous ablation for atrial fibrillation

    Energy Technology Data Exchange (ETDEWEB)

    Maksimovic, Ruzica [Erasmus Medical Center, Department of Radiology, GD Rotterdam (Netherlands); Institute for Cardiovascular Diseases of the University Medical Center, Belgrade (Czechoslovakia); Dill, Thorsten [Kerckhoff-Heart Center, Department of Cardiology, Bad Nauheim (Germany); Ristic, Arsen D.; Seferovic, Petar M. [Institute for Cardiovascular Diseases of the University Medical Center, Belgrade (Czechoslovakia)

    2006-11-15

    Percutaneous ablation for electrical disconnection of the arrhythmogenic foci using various forms of energy has become a well-established technique for treating atrial fibrillation (AF). Success rate in preventing recurrence of AF episodes is high although associated with a significant incidence of pulmonary vein (PV) stenosis and other rare complications. Clinical workup of AF patients includes imaging before and after ablative treatment using different noninvasive and invasive techniques such as conventional angiography, transoesophageal and intracardiac echocardiography, computed tomography (CT) and magnetic resonance imaging (MRI), which offer different information with variable diagnostic accuracy. Evaluation before percutaneous ablation involves assessment of PVs (PV pattern, branching pattern, orientation and ostial size) to facilitate position and size of catheters and reduce procedure time as well as examining the left atrium (presence of thrombi, dimensions and volumes). Imaging after the percutaneous ablation is important for assessment of overall success of the procedure and revealing potential complications. Therefore, imaging methods enable depiction of PVs and the anatomy of surrounding structures essential for preprocedural management and early detection of PV stenosis and other ablation-related procedures, as well as long-term follow-up of these patients. (orig.)

  11. Quality of life in atrial fibrillation.

    Science.gov (United States)

    Lüderitz, B; Jung, W

    2000-01-01

    In patients with atrial fibrillation (AF), the restoration and maintenance of sinus rhythm is the primary therapeutic goal. Once sinus rhythm is maintained, physiological rate control is restored, and left ventricular ejection fraction, cardiac output, and exercise capacity are increased. This improved cardiovascular performance thereby enhances the patient's ability to perform the functions of normal daily life. The primary intervention for maintaining sinus rhythm after restoration is the use of anti-arrhythmic agents. Although physicians mostly use class 1A anti-arrhythmic drugs, these oral agents only maintain sinus rhythm in a limited number of cases and are accompanied by considerable side effects. Therefore, more effective tools are needed. Effective treatment for AF is based on the above objective criteria, but subjective criteria such as the quality of life are growing in importance. To address these quality-of-life issues, we have initiated a prospective study in which patients are assigned to one of two groups: those with paroxysmal AF who are candidates for permanent implantable atrial defibrillators and those with chronic or paroxysmal AF who are not candidates for atrial defibrillators. Specifically designed questionnaires and various standardized and validated instruments are used to measure quality of life. The questionnaires cover social demographic data, including age, education, occupation level, driving behavior, return to work, and sexual activity. Quality of life is a multidimensional construct, and thus its definition must consider the many factors mentioned above. In the final analysis, therefore, both objective and subjective criteria are necessary to define appropriate treatment of AF.

  12. Defibrillation for Ventricular Fibrillation: A Shocking Update.

    Science.gov (United States)

    Nichol, Graham; Sayre, Michael R; Guerra, Federico; Poole, Jeanne

    2017-09-19

    Cardiac arrest is defined as the termination of cardiac activity associated with loss of consciousness, of spontaneous breathing, and of circulation. Sudden cardiac arrest and sudden cardiac death (SCD) are terms often used interchangeably. Most patients with out-of-hospital cardiac arrest have shown coronary artery disease or symptoms during the hour before the event. Cardiac arrest is potentially reversible by cardiopulmonary resuscitation, defibrillation, cardioversion, cardiac pacing, or treatments targeted at the underlying disease (e.g., acute coronary occlusion). We restrict SCD hereafter to cardiac arrest due to ventricular fibrillation, including rhythms shockable by an automatic external defibrillator (AED), implantable cardioverter-defibrillator (ICD), or wearable cardioverter-defibrillator (WCD). We summarize the state of the art related to defibrillation in treating SCD, including a brief history of the evolution of defibrillation, technical characteristics of modern AEDs, strategies to improve AED access and increase survival, ancillary treatments, and use of ICDs or WCDs. Copyright © 2017 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

  13. Atrial Fibrillation Predictors: Importance of the Electrocardiogram.

    Science.gov (United States)

    German, David M; Kabir, Muammar M; Dewland, Thomas A; Henrikson, Charles A; Tereshchenko, Larisa G

    2016-01-01

    Atrial fibrillation (AF) is the most common arrhythmia in adults and is associated with significant morbidity and mortality. Substantial interest has developed in the primary prevention of AF, and thus the identification of individuals at risk for developing AF. The electrocardiogram (ECG) provides a wealth of information, which is of value in predicting incident AF. The PR interval and P wave indices (including P wave duration, P wave terminal force, P wave axis, and other measures of P wave morphology) are discussed with regard to their ability to predict and characterize AF risk in the general population. The predictive value of the QT interval, ECG criteria for left ventricular hypertrophy, and findings of atrial and ventricular ectopy are also discussed. Efforts are underway to develop models that predict AF incidence in the general population; however, at present, little information from the ECG is included in these models. The ECG provides a great deal of information on AF risk and has the potential to contribute substantially to AF risk estimation, but more research is needed. © 2015 Wiley Periodicals, Inc.

  14. Red Wine, Resveratrol and Atrial Fibrillation

    Directory of Open Access Journals (Sweden)

    Laura Siga Stephan

    2017-10-01

    Full Text Available Atrial fibrillation (AF is a common cardiac arrhythmia that is associated with increased risk for cardiovascular disease and overall mortality. Excessive alcohol intake is a well-known risk factor for AF, but this correlation is less clear with light and moderate drinking. Besides, low doses of red wine may acutely prolong repolarization and slow cardiac conduction. Resveratrol, a bioactive polyphenol found in grapes and red wine, has been linked to antiarrhythmic properties and may act as an inhibitor of both intracellular calcium release and pathological signaling cascades in AF, eliminating calcium overload and preserving the cardiomyocyte contractile function. However, there are still no clinical trials at all that prove that resveratrol supplementation leads to improved outcomes. Besides, no observational study supports a beneficial effect of light or moderate alcohol intake and a lower risk of AF. The purpose of this review is to briefly describe possible beneficial effects of red wine and resveratrol in AF, and also present studies conducted in humans regarding chronic red wine consumption, resveratrol, and AF.

  15. ANTIARRHYTHMIC EFFICACY OF PROPAFENONE IN PATIENTS WITH PERSISTENT ATRIAL FIBRILLATION

    Directory of Open Access Journals (Sweden)

    R. D. Kurbanov

    2011-01-01

    Full Text Available Aim. To assess propafenone antiarrhythmic efficacy and optimal timing of the drug administration for relief of persistent atrial fibrillation (PAF. Material and methods. 24 patients (19 men, 5 women, aged 53,8±13,3 with PAF (duration is more than 7 days were included in the study. PAF was confirmed clinically as well as by ECG and daily ECG monitoring. Indications for sinus rhythm recovery by propafenone were defined in according to the ACC/AHA/ESC recommendations (2006. 12-lead ECG was performed before the fist administration and 2, 4, 8, 12, 24 hours and some next days after propafenone therapy start. Echocardiography and thyroid hormone tests were also performed. Propafenone was administered additionally to standard treatment of the underlying disease and oral anticoagulants. The first dose of propafenone was 300 mg, after 4 hours patients received next dose of 300 mg if atrial fibrillation persisted and no side effects were observed, then doses of 300 mg were administered every 6-8 hours (but not more than 900-1200 mg per day during 5 days. Maintenance propafenone dose of 450-600 mg daily was used in case of sinus rhythm recovery. Results. Sinus rhythm was restored in 41,6% of patients taking propafenone, and time of sinus rhythm recovery was 53,1±28,9 hours after therapy start. Propafenone antiarrhythmic efficacy in the loading dose (300 mg was 4,2%. Propafenone efficacy during the first 24 hours (dose of 700±282,8 mg was 12,5%. The maximum rate of sinus rhythm recovery was observed during the first 2-3 days of propafenone receiving (60% of all patients with rhythm recovery. Patients with unrecovered sinus rhythm had longer duration of PAF in comparison with this in effectively treated patients, 105,8±89,0 vs 39,7±38,9 days (p<0,05, respectively, as well as the more prominent basal pulse deficit, 24,6±15,0 vs 13,56±5,7 beats per minute (p<0,05, respectively. Cardiac and transient noncardiac side effects were registered in 8,6 and 4

  16. Carbohydrate Loading.

    Science.gov (United States)

    Csernus, Marilyn

    Carbohydrate loading is a frequently used technique to improve performance by altering an athlete's diet. The objective is to increase glycogen stored in muscles for use in prolonged strenuous exercise. For two to three days, the athlete consumes a diet that is low in carbohydrates and high in fat and protein while continuing to exercise and…

  17. Clustering of RR intervals predicts effective electrical cardioversion for atrial fibrillation

    NARCIS (Netherlands)

    Van den Berg, MP; Van Noord, T; Brouwer, J; Haaksma, J; Van Veldhuisen, DJ; Crijns, HJGM; Van Gelder, IC

    Electrical Cardioversion for Atrial Fibrillation. Introduction: Atrial fibrillation (AF) is characterized by an irregularly irregular ("random") heart beat. However, controversy exists whether the ventricular rhythm in AF is truly random. We investigated randomness by constructing three-dimensional

  18. Radiofrequency catheter ablation maintains its efficacy better than antiarrhythmic medication in patients with paroxysmal atrial fibrillation

    DEFF Research Database (Denmark)

    Raatikainen, M J Pekka; Hakalahti, Antti; Uusimaa, Paavo

    2015-01-01

    BACKGROUND: The Medical ANtiarrhythmic Treatment or Radiofrequency Ablation in Paroxysmal Atrial Fibrillation (MANTRA-PAF) is a randomized trial comparing radiofrequency catheter ablation (RFA) to antiarrhythmic drugs (AADs) as first-line treatment of paroxysmal atrial fibrillation (PAF). In order...

  19. Risk of atrial fibrillation as a function of the electrocardiographic PR interval

    DEFF Research Database (Denmark)

    Nielsen, Jonas Bille; Pietersen, Adrian; Graff, Claus

    2013-01-01

    Prolongation of the PR interval has been associated with an increased risk of incident atrial fibrillation (AF).......Prolongation of the PR interval has been associated with an increased risk of incident atrial fibrillation (AF)....

  20. Flexibility of backbone fibrils in α-chitin crystals with different degree of acetylation.

    Science.gov (United States)

    Yu, Zechuan; Lau, Denvid

    2017-10-15

    Acetyl groups are backbone outreaches that enhance inter-fibril connection in chitin and chitosan fibril bundle. Removal of acetyl groups affects flexibility of chitosan fibril bundle, thereby affecting mechanical strength of chitosan-based products. Understandings of relationship between degree of acetylation and flexibility of chitin fibril bundle conduce to optimization of synthetic chitin materials. Here, the relationship is examined by performing molecular dynamics simulations. Coiling of chitin and chitosan fibril bundle with different degree of acetylation is observed and flexibility of fibrils is measured. Number and alignment of acetyl groups are found to be important factors determining the flexibility of chitin and chitosan fibril bundle. Structural instability can be caused by incompatible alignment of acetyl groups. Our findings on synthetic chitin-based materials indicate that adding a small amount of acetyl groups to chitosan can significantly enhance the integrity of fibril bundle. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. The changing face of glucagon fibrillation: Structural polymorphism and conformational imprinting

    DEFF Research Database (Denmark)

    Pedersen, J.S.; Dikov, D.; Flink, J.L.

    2006-01-01

    We have established a time-resolved fluorescence assay to study fibrillation of the 29 residue peptide hormone glucagon under a variety of different conditions in a high-throughput format. Fibrils formed at pH 2.5 differ in fibrillation kinetics, morphology, thioflavin T staining and FTIR....../CD spectra depending on salts, glucagon concentration and fibrillation temperature. Apparent fibrillar stability correlates with spectral and kinetic properties; generally, fibrils formed under conditions favourable for rapid fibrillation (ambient temperatures, high glucagon concentration or high salt...... concentration) appear less thermostable than those formed under more challenging conditions (high temperatures, low glucagon or low salt concentrations). Properties of preformed fibrils used for seeding are inherited in a prion-like manner. Thus, we conclude that the structure of fibrils formed by glucagon...

  2. Alterations in gene expression of proteins involved in the calcium handling in patients with atrial fibrillation

    NARCIS (Netherlands)

    Van Gelder, IC; Brundel, BJJM; Henning, RH; Tuinenburg, AE; Tieleman, RG; Deelman, L; Grandjean, JG; De Kam, PJ; Van Gilst, WH; Crijns, HJGM

    Gene Expression in Human Atrial Fibrillation, Introduction: Atrial fibrillation (AF) leads to a loss of atrial contraction within hours to days. During persistence of AF, cellular dedifferentiation and hypertrophy occur, eventually resulting in degenerative changes and cell death, Abnormalities in

  3. Quantitative morphological analysis reveals ultrastructural diversity of amyloid fibrils from alpha-synuclein mutants

    NARCIS (Netherlands)

    van Raaij, Martijn E; Segers-Nolten, Ine M J; Subramaniam, Vinod

    2006-01-01

    High resolution atomic force microscopy is a powerful tool to characterize nanoscale morphological features of protein amyloid fibrils. Comparison of fibril morphological properties between studies has been hampered by differences in analysis procedures and measurement error determination used by

  4. Impaired autonomic function predicts dizziness at onset of paroxysmal atrial fibrillation

    NARCIS (Netherlands)

    van den Berg, MP; Hassink, RJ; Tuinenburg, AE; Lefrandt, JD; de Kam, PJ; Crijns, HJGM

    2001-01-01

    Background: Paroxysmal atrial fibrillation is associated with various symptoms, including dizziness, which presumably reflects hemodynamic deterioration. Given the importance of the autonomic nervous system in mitigating the hemodynamic effect of atrial fibrillation, we hypothesized that autonomic

  5. A randomized study of the effects of exercise training on patients with atrial fibrillation

    DEFF Research Database (Denmark)

    Osbak, Philip Samuel; Mourier, Malene; Kjaer, Andreas

    2011-01-01

    Exercise training is beneficial in ischemic and congestive heart disease. However, the effect on atrial fibrillation (AF) is unknown.......Exercise training is beneficial in ischemic and congestive heart disease. However, the effect on atrial fibrillation (AF) is unknown....

  6. Atrial fibrillation and heart failure in cardiology practice: reciprocal impact and combined management from the perspective of atrial fibrillation: results of the Euro Heart Survey on atrial fibrillation

    NARCIS (Netherlands)

    Nieuwlaat, Robby; Eurlings, Luc W.; Cleland, John G.; Cobbe, Stuart M.; Vardas, Panos E.; Capucci, Alessandro; López-Sendòn, José L.; Meeder, Joan G.; Pinto, Yigal M.; Crijns, Harry J. G. M.

    2009-01-01

    OBJECTIVES: Our aim was to identify shortcomings in the management of patients with both atrial fibrillation (AF) and heart failure (HF). BACKGROUND: AF and HF often coincide in cardiology practice, and they are known to worsen each other's prognosis, but little is known about the quality of care of

  7. Survey of Transmission Cost Allocation Methodologies for Regional Transmission Organizations

    Energy Technology Data Exchange (ETDEWEB)

    Fink, S.; Porter, K.; Mudd, C.; Rogers, J.

    2011-02-01

    The report presents transmission cost allocation methodologies for reliability transmission projects, generation interconnection, and economic transmission projects for all Regional Transmission Organizations.

  8. Impact of Investments in Generating Units and Transmission and Distribution Power Grids by 2025 on Voltage Stability and Branches Load in ENERGA SA Operational Territory – Main Findings of Research Project

    Directory of Open Access Journals (Sweden)

    Dominik Falkowski

    2013-03-01

    Full Text Available The article summarizes a research project which was conducted in order to ensure what will be the influence of future investments and changes in the Polish Power System on the stability and functionality of the ENERGA SA distribution grid system. Development of the ENERGA SA distribution grid system was also included. Only stable states were tested for various cases of system load and generation in power plants (the Nuclear Power Plant in Żarnowiec was taken into account and also in wind farms. The system was also tested in N-1 and N-2 states. The result of this study is an overall evaluation of the ENERGA SA distribution grid condition, as well as the identification of potential weak points inside this structure.

  9. Nanoscale Swelling Heterogeneities in Type I Collagen Fibrils.

    Science.gov (United States)

    Spitzner, Eike-Christian; Röper, Stephanie; Zerson, Mario; Bernstein, Anke; Magerle, Robert

    2015-06-23

    The distribution of water within the supramolecular structure of collagen fibrils is important for understanding their mechanical properties as well as the biomineralization processes in collagen-based tissues. We study the influence of water on the shape and the mechanical properties of reconstituted fibrils of type I collagen on the nanometer scale. Fibrils adsorbed on a silicon substrate were imaged with multiset point intermittent contact (MUSIC)-mode atomic force microscopy (AFM) in air at 28% relative humidity (RH) and in a hydrated state at 78% RH. Our data reveal the differences in the water uptake between the gap and overlap regions during swelling. This provides direct evidence for different amounts of bound and free water within the gap and overlap regions. In the dry state, the characteristic D-band pattern visible in AFM images is due to height corrugations along a fibril's axis. In the hydrated state, the fibril's surface is smooth and the D-band pattern reflects the different mechanical properties of the gap and overlap regions.

  10. Long-term efficacy of catheter ablation as first-line therapy for paroxysmal atrial fibrillation

    DEFF Research Database (Denmark)

    Nielsen, Jens Cosedis; Johannessen, Arne; Raatikainen, Pekka

    2016-01-01

    OBJECTIVE: The Medical ANtiarrhythmic Treatment or Radiofrequency Ablation in Paroxysmal Atrial Fibrillation (MANTRA-PAF) trial compared radiofrequency catheter ablation (RFA) with antiarrhythmic drug therapy (AAD) as first-line treatment for paroxysmal atrial fibrillation (AF). Endpoint of ablat......OBJECTIVE: The Medical ANtiarrhythmic Treatment or Radiofrequency Ablation in Paroxysmal Atrial Fibrillation (MANTRA-PAF) trial compared radiofrequency catheter ablation (RFA) with antiarrhythmic drug therapy (AAD) as first-line treatment for paroxysmal atrial fibrillation (AF). Endpoint...

  11. Transmission congestion management in the electricity market

    Science.gov (United States)

    Chen, Yue

    2018-04-01

    In this paper we mainly discuss how to optimize the arrangement to decrease the loss of each line when the power generation side of the system transmission congestion occurs in a safe and economical manner. We respectively set the adjust model if the transmission can be eliminated which can calculate the best scheme and safety margin model when transmission cannot be eliminated which is a multi-objective planning problem. We solve the two models on the condition of the load power demands are 982.4MW and 1052.8 MW by Lingo and get the optimal management scheme.

  12. Endocytosed 2-Microglobulin Amyloid Fibrils Induce Necrosis and Apoptosis of Rabbit Synovial Fibroblasts by Disrupting Endosomal/Lysosomal Membranes: A Novel Mechanism on the Cytotoxicity of Amyloid Fibrils.

    Directory of Open Access Journals (Sweden)

    Tadakazu Okoshi

    Full Text Available Dialysis-related amyloidosis is a major complication in long-term hemodialysis patients. In dialysis-related amyloidosis, β2-microglobulin (β2-m amyloid fibrils deposit in the osteoarticular tissue, leading to carpal tunnel syndrome and destructive arthropathy with cystic bone lesions, but the mechanism by which these amyloid fibrils destruct bone and joint tissue is not fully understood. In this study, we assessed the cytotoxic effect of β2-m amyloid fibrils on the cultured rabbit synovial fibroblasts. Under light microscopy, the cells treated with amyloid fibrils exhibited both necrotic and apoptotic changes, while the cells treated with β2-m monomers and vehicle buffer exhibited no morphological changes. As compared to β2-m monomers and vehicle buffer, β2-m amyloid fibrils significantly reduced cellular viability as measured by the lactate dehydrogenase release assay and the 3-(4,5-di-methylthiazol-2-yl-2,5-diphenyltetrazolium bromide reduction assay and significantly increased the percentage of apoptotic cells as measured by the terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling method. β2-m amyloid fibrils added to the medium adhered to cell surfaces, but did not disrupt artificial plasma membranes as measured by the liposome dye release assay. Interestingly, when the cells were incubated with amyloid fibrils for several hours, many endosomes/lysosomes filled with amyloid fibrils were observed under confocal laser microscopy and electron microscopy, Moreover, some endosomal/lysosomal membranes were disrupted by intravesicular fibrils, leading to the leakage of the fibrils into the cytosol and adjacent to mitochondria. Inhibition of actin-dependent endocytosis by cytochalasin D attenuated the toxicity of amyloid fibrils. These results suggest that endocytosed β2-m amyloid fibrils induce necrosis and apoptosis by disrupting endosomal/lysosomal membranes, and this novel mechanism on the cytotoxicity of amyloid

  13. Increasing rate of atrial fibrillation from 2003 to 2011 in patients with ischaemic stroke

    DEFF Research Database (Denmark)

    Jespersen, S F; Christensen, L. M.; Christensen, A

    2015-01-01

    identified. Frequency analysis and linear regression were used to assess trends in atrial fibrillation diagnosis and oral anticoagulation therapy prescription. RESULTS: A total of 17.1% (n = 9482) of ischaemic stroke patients had atrial fibrillation. The relative frequency of atrial fibrillation increased...

  14. 77 FR 11121 - Scientific Information Request on Treatment of Atrial Fibrillation

    Science.gov (United States)

    2012-02-24

    ... Atrial Fibrillation AGENCY: Agency for Healthcare Research and Quality (AHRQ), HHS. ACTION: Request for... scientific information submissions from manufacturers of atrial fibrillation medical devices. Scientific... effectiveness review of the evidence for the treatment of atrial fibrillation. The EHC Program is dedicated to...

  15. 78 FR 11207 - Clinical Study Designs for Surgical Ablation Devices for Treatment of Atrial Fibrillation...

    Science.gov (United States)

    2013-02-15

    ... Treatment of Atrial Fibrillation; Guidance for Industry and Food and Drug Administration Staff; Availability... Ablation Devices for Treatment of Atrial Fibrillation.'' This guidance provides FDA's recommendations on clinical trial designs for surgical ablation devices intended for the treatment of atrial fibrillation...

  16. Meta-analysis identifies six new susceptibility loci for atrial fibrillation

    NARCIS (Netherlands)

    Ellinor, Patrick T; Lunetta, Kathryn L; Albert, Christine M; Glazer, Nicole L; Ritchie, Marylyn D; Smith, Albert V; Arking, Dan E; Müller-Nurasyid, Martina; Krijthe, Bouwe P; Lubitz, Steven A; Bis, Joshua C; Chung, Mina K; Dörr, Marcus; Ozaki, Kouichi; Roberts, Jason D; Smith, J Gustav; Pfeufer, Arne; Sinner, Moritz F; Lohman, Kurt; Ding, Jingzhong; Smith, Nicholas L; Smith, Jonathan D; Rienstra, Michiel; Rice, Kenneth M; Van Wagoner, David R; Magnani, Jared W; Wakili, Reza; Clauss, Sebastian; Rotter, Jerome I; Steinbeck, Gerhard; Launer, Lenore J; Davies, Robert W; Borkovich, Matthew; Harris, Tamara B; Lin, Honghuang; Völker, Uwe; Völzke, Henry; Milan, David J; Hofman, Albert; Boerwinkle, Eric; Chen, Lin Y; Soliman, Elsayed Z; Voight, Benjamin F; Li, Guo; Chakravarti, Aravinda; Kubo, Michiaki; Tedrow, Usha B; Rose, Lynda M; Ridker, Paul M; Conen, David; Tsunoda, Tatsuhiko; Furukawa, Tetsushi; Sotoodehnia, Nona; Xu, Siyan; Kamatani, Naoyuki; Levy, Daniel; Nakamura, Yusuke; Parvez, Babar; Mahida, Saagar; Furie, Karen L; Rosand, Jonathan; Muhammad, Raafia; Psaty, Bruce M; Meitinger, Thomas; Perz, Siegfried; Wichmann, H-Erich; Witteman, Jacqueline C M; Kao, W H Linda; Kathiresan, Sekar; Roden, Dan M; Uitterlinden, Andre G; Rivadeneira, Fernando; McKnight, Barbara; Sjögren, Marketa; Newman, Anne B; Liu, Yongmei; Gollob, Michael H; Melander, Olle; Tanaka, Toshihiro; Stricker, Bruno H Ch; Felix, Stephan B; Alonso, Alvaro; Darbar, Dawood; Barnard, John; Chasman, Daniel I; Heckbert, Susan R; Benjamin, Emelia J; Gudnason, Vilmundur; Kääb, Stefan

    Atrial fibrillation is a highly prevalent arrhythmia and a major risk factor for stroke, heart failure and death. We conducted a genome-wide association study (GWAS) in individuals of European ancestry, including 6,707 with and 52,426 without atrial fibrillation. Six new atrial fibrillation

  17. Pyroglutamate-Modified Amyloid β (11- 40) Fibrils Are More Toxic than Wildtype Fibrils but Structurally Very Similar.

    Science.gov (United States)

    Scheidt, Holger A; Adler, Juliane; Zeitschel, Ulrike; Höfling, Corinna; Korn, Alexander; Krueger, Martin; Roßner, Steffen; Huster, Daniel

    2017-11-07

    The morphology, structure, and dynamics of mature amyloid β (Aβ) fibrils formed by the Aβ variant, which is truncated at residue 11 and chemically modified by enzymatic pyroglutamate formation (pGlu 11 -Aβ(11-40)), was studied along with the investigation of the toxicity of these Aβ variants to neurons and astrocytes. The fibrils of pGlu 11 -Aβ (11-40) were more toxic than wildtype Aβ (1-40) and the longer pGlu3-Aβ (3-40) especially at higher concentration, whereas the overall morphology was quite similar. The secondary structure of pGlu 11 -Aβ (11-40) fibrils shows the typical two β-strands connected by a short turn as known for mature fibrils of Aβ (1-40) and also pGlu 3 -Aβ (3-40). Further insights into tertiary contacts exhibit some similarities of pGlu 11 -Aβ (11-40) fibrils with wildtype Aβ (1-40), but also a so far not described contact between Gly 25 and Ile 31 . This highlights the biological importance of chemical modifications on the molecular structure of Aβ. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. The immediate future for the medical treatment of atrial fibrillation

    DEFF Research Database (Denmark)

    Pedersen, Ole Dyg; Brendorp, Bente; Køber, Lars

    2002-01-01

    Atrial fibrillation is the most commonly sustained cardiac arrhythmia and a common reason for mortality and morbidity. Atrial fibrillation causes disease for three reasons: i) the ventricular rate is often high, which leads to symptoms ranging from discomfort to life threatening heart failure; ii......) the rhythm causes loss of atrioventricular synchrony, which reduces diastolic filling and may lead to heart failure; and iii) atrial contraction is lost leading to stagnant blood that again may lead to atrial thrombi and peripheral embolism. Thus, the treatment of atrial fibrillation is focused...... of sinus rhythm but all carry a significant risk of pro-arrhythmia, in particular Torsade de Pointe ventricular tachycardia. Rate control has been a focus of treatment for many years and several very old drugs, including digoxin, are used for this. There is, to the author's knowledge, no current effort...

  19. D-Ser-containing humanin shows promotion of fibril formation.

    Science.gov (United States)

    Hayashi, Kanehiro; Sasabe, Jumpei; Chiba, Tomohiro; Aiso, Sadakazu; Utsunomiya-Tate, Naoko

    2012-06-01

    Humanin (HN), a peptide of 24 amino acid residues, suppresses the neuronal cell death that is induced by the gene products of Alzheimer's disease. HN contains two Ser residues at positions 7 and 14. Because the proportion of D-Ser isomerized from L-Ser in proteins appears to increase as cellular organs age, we explored the structural effects of the isomerization of each Ser residue in HN. By using a thioflavin-T assay to detect fibril formation, we found that an HN derivative that contained two isomerized D-Ser residues had a greater tendency to form fibrils than did wild-type HN or HNs containing single D-Ser residues. A previous report showed that HN containing two D-Ser residues exerts neuroprotective activity. Our data, therefore, suggest that the fibril formation by HN that contains two D-Ser residues may promote HN neuroprotective activity.

  20. Distinct increase in hematocrit associated with paroxysm of atrial fibrillation.

    Science.gov (United States)

    Okuno, S; Ashida, T; Ebihara, A; Sugiyama, T; Fujii, J

    2000-09-01

    In a previous study we found that hemoconcentration, which was identified by an increase in hematocrit, occured during a paroxysm of atrial fibrillation. In the present study we investigated the changes in hematocrit from sinus rhythm to paroxysm in 10 patients who had multiple paroxysms of atrial fibrillation in order to assess the ranges of the changes in hematocrit among the paroxysms. In these patients hematocrit was measured simultaneously with electrocardiographic recording during 3 or more paroxysms and sinus rhythm just before each paroxysm. The changes in hematocrit varied among the paroxysms. The maximum increase in hematocrit in each patient ranged from 3.5 to 8.0 points with an average of 5.1 points. Such a distinct increase in hematocrit which abruptly develops with a paroxysm of atrial fibrillation may be a potential risk for thrombus formation.

  1. Headache during cryoballoon ablation for atrial fibrillation.

    Science.gov (United States)

    Pison, Laurent; Peeters, Pim; Blaauw, Yuri; Vernooy, Kevin; Kumar, Narendra; Philippens, Suzanne; Crijns, Harry J; Vlaeyen, Johan; Schoenen, Jean; Timmermans, Carl

    2015-06-01

    Headache has been reported to occur during cryoballoon ablation for atrial fibrillation (AF). No study has systematically analysed this phenomenon. Twenty consecutive patients with symptomatic AF underwent cryoballoon ablation without sedation. Headache was evaluated before, during, and after the first cryoapplication in every pulmonary vein (PV) using a visual representation of a head for location of the headache, a numerical rating scale (NRS) for measuring pain intensity and the short-form McGill pain questionnaire (MPQ) for qualitative analysis of pain. The order in which the PVs were ablated was randomized. Sixteen (80%) patients perceived mainly frontal headache during cryoablation. The overall NRS scores were significantly higher during (5.1 ± 1.7), compared with before (2.7 ± 1.4), and after (3.5 ± 2.2) a cryoapplication (P < 0.05). The NRS score was significantly higher during ablation of the first PV. The intensity of the perceived headache was not related to the temperature reached 150 s after initiation of a cryoapplication (P = 0.81). Of the MPQ, three sensory adjectives and one affective adjective averaged between scores 1 and 2, representing mild-to-moderate severity of pain. The majority of patients treated by balloon cryoablation experienced headache during a cryoapplication. There was no correlation between the temperature reached during a cryoballoon freeze and the intensity of the headache. Cryoballoon ablation of the first PV was significantly more painful than the remaining PVs. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2015. For permissions please email: journals.permissions@oup.com.

  2. Measuring the complexity of atrial fibrillation electrograms.

    Science.gov (United States)

    Ng, Jason; Borodyanskiy, Aleksey I; Chang, Eric T; Villuendas, Roger; Dibs, Samer; Kadish, Alan H; Goldberger, Jeffrey J

    2010-06-01

    Complex fractionated atrial electrograms (CFAE) have been identified as targets for atrial fibrillation (AF) ablation. Robust automatic algorithms to objectively classify these signals would be useful. The aim of this study was to evaluate Shannon's entropy (ShEn) and the Kolmogorov-Smirnov (K-S) test as a measure of signal complexity and to compare these measures with fractional intervals (FI) in distinguishing CFAE from non-CFAE signals. Electrogram recordings of 5 seconds obtained from multiple atrial sites in 13 patients (11 M, 58 +/- 10 years old) undergoing AF ablation were visually examined by 4 independent reviewers. Electrograms were classified as CFAE if they met Nademanee criteria. Agreement of 3 or more reviewers was considered consensus and the resulting classification was used as the gold standard. A total of 297 recordings were examined. Of these, 107 were consensus CFAE, 111 were non-CFAE, and 79 were equivocal or noninterpretable. FIs less than 120 ms identified CFAEs with sensitivity of 87% and specificity of 79%. ShEn, with optimal parameters using receiver-operator characteristic curves, resulted in a sensitivity of 87% and specificity of 81% in identifying CFAE. The K-S test resulted in an optimal sensitivity of 100% and specificity of 95% in classifying uninterpretable electrogram from all other electrograms. ShEn showed comparable results to FI in distinguishing CFAE from non-CFAE without requiring user input for threshold levels. Thus, measuring electrogram complexity using ShEn may have utility in objectively and automatically identifying CFAE sites for AF ablation.

  3. An Integrated Management Approach to Atrial Fibrillation.

    Science.gov (United States)

    Carter, Lindsey; Gardner, Martin; Magee, Kirk; Fearon, Ann; Morgulis, Inna; Doucette, Steve; Sapp, John L; Gray, Chris; Abdelwahab, Amir; Parkash, Ratika

    2016-01-25

    Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia resulting in mortality and morbidity. Gaps in oral anticoagulation and education of patients regarding AF have been identified as areas that require improvement. A before-and-after study of 433 patients with newly diagnosed AF in the 3 emergency departments in Nova Scotia from January 1, 2011 until January 31, 2014 was performed. The "before" phase underwent the usual-care pathway for AF management; the "after" phase was enrolled in a nurse-run, physician-supervised AF clinic. The primary outcome was a composite of death, cardiovascular hospitalization, and AF-related emergency department visits. A propensity analysis was performed to account for differences in baseline characteristics. A total of 185 patients were enrolled into the usual-care group, and 228 patients were enrolled in the AF clinic group. The mean age was 64±15 years and 44% were women. In a propensity-matched analysis, the primary outcome occurred in 44 (26.2%) patients in the usual-care group and 29 (17.3%) patients in the AF clinic group (odds ratio 0.71; 95% CI [0.59, 1]; P=0.049) at 12 months. Prescription of oral anticoagulation was increased in the CHADS2 ≥2 group (88.4% in the AF clinic versus 58.5% in the usual-care group, Pmanagement approach for the burgeoning population of AF may provide an overall benefit to cardiovascular morbidity and mortality. © 2016 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley Blackwell.

  4. Modelación de las cargas de reacción en los apoyos de los árboles de la Transmisión por tornillo sinfín. // Reaction loads models in shafts supports of worm gear transmissions.

    Directory of Open Access Journals (Sweden)

    G. Rivero Llerena

    2006-05-01

    Full Text Available El análisis y cálculo de las cargas que se generan en los apoyos de los árboles de los conjuntos mecánicos rotatorios, resultaun proceso complejo pero imprescindible en la tarea de selección de los rodamientos, por ello en el presente trabajo sepropone el uso de las NTIC como herramientas efectivas de diseño y modelación para la solución de este problema. En estainvestigación se trata el caso de la transmisión por tornillo sinfín por su importancia en los accionamientos industriales y enotros campos, se ha formalizado en tres modelos, el análisis de las cargas de operación y de reacción que se producendurante el funcionamiento. Se presentan los resultados que puede brindar el software de cálculo creado, usando el paquetede información que contiene la modelación realizada para obtener una respuesta ágil y exacta de las cargas de reacciónresultantes en los apoyos de árboles.Palabras claves: Sinfín, rodamiento, modelación.______________________________________________________________________________Abstract.The analysis and calculation of the loads generated in the shafts supports of the rotational machines, is a complex butindispensable process in the task of selection rolling bearings. The present paper exposes the use of the NTIC like effectivetools of design and modelling in order to solve this problem. The worm gear transmission case is studied in thisinvestigation because their importance in the industrial machinery and other fields, the analysis of the operation andreaction loads has been formalized in three models. Also it is presented the results of software for calculation, using theinformation package that contains the three models for obtaining an agile and exact answer of the resulting reaction loads inthe shafts supports.Key words: Worm gear, bearing, modelling.

  5. Exposure-Based Therapy for Symptom Preoccupation in Atrial Fibrillation

    DEFF Research Database (Denmark)

    Särnholm, Josefin; Skúladóttir, Helga; Rück, Christian

    2017-01-01

    Atrial fibrillation (AF) is the most common cardiac arrhythmia. Patients often experience a range of symptoms resulting in a markedly reduced quality of life, and commonly show symptom preoccupation in terms of avoidance and control behaviors. Cognitive behavior therapy (CBT) has been shown...... with symptomatic paroxysmal (intermittent) atrial fibrillation who were assessed pre- and posttreatment and at 6-month follow-up. The CBT lasted 10 weeks and included exposure to physical sensations similar to AF symptoms, exposure to avoided situations or activities, and behavioral activation. We observed large...

  6. Management and prognosis of atrial fibrillation in diabetic patients

    DEFF Research Database (Denmark)

    Fumagalli, Stefano; Said, Salah A; Laroche, Cecile

    2017-01-01

    Aims: Diabetes mellitus (DM) is one of the most important cardiovascular (CV) risk factors. The aim of this study was to evaluate clinical correlates of DM, including management and outcomes, in the EURObservational Research Programme (EORP) - Atrial Fibrillation (AF) General Pilot (EORP-AF) Regi......Aims: Diabetes mellitus (DM) is one of the most important cardiovascular (CV) risk factors. The aim of this study was to evaluate clinical correlates of DM, including management and outcomes, in the EURObservational Research Programme (EORP) - Atrial Fibrillation (AF) General Pilot (EORP...

  7. Transmission usage cost allocation schemes

    International Nuclear Information System (INIS)

    Abou El Ela, A.A.; El-Sehiemy, R.A.

    2009-01-01

    This paper presents different suggested transmission usage cost allocation (TCA) schemes to the system individuals. Different independent system operator (ISO) visions are presented using the proportional rata and flow-based TCA methods. There are two proposed flow-based TCA schemes (FTCA). The first FTCA scheme generalizes the equivalent bilateral exchanges (EBE) concepts for lossy networks through two-stage procedure. The second FTCA scheme is based on the modified sensitivity factors (MSF). These factors are developed from the actual measurements of power flows in transmission lines and the power injections at different buses. The proposed schemes exhibit desirable apportioning properties and are easy to implement and understand. Case studies for different loading conditions are carried out to show the capability of the proposed schemes for solving the TCA problem. (author)

  8. Circadian variation in dominant atrial fibrillation frequency in persistent atrial fibrillation

    International Nuclear Information System (INIS)

    Sandberg, Frida; Stridh, Martin; Sörnmo, Leif; Bollmann, Andreas; Husser, Daniela

    2010-01-01

    Circadian variation in atrial fibrillation (AF) frequency is explored in this paper by employing recent advances in signal processing. Once the AF frequency has been estimated and tracked by a hidden Markov model approach, the resulting trend is analyzed for the purpose of detecting and characterizing the presence of circadian variation. With cosinor analysis, the results show that the short-term variations in the AF frequency exceed the variation that may be attributed to circadian. Using the autocorrelation method, circadian variation was found in 13 of 18 ambulatory ECG recordings (Holter) acquired from patients with long-standing persistent AF. Using the ensemble correlation method, the highest AF frequency usually occurred during the afternoon, whereas the lowest usually occurred during late night. It is concluded that circadian variation is present in most patients with long-standing persistent AF though the short-term variation in the AF frequency is considerable and should be taken into account

  9. Prevalence of atrial fibrillation in Greece: the Arcadia Rural Study on Atrial Fibrillation.

    Science.gov (United States)

    Ntaios, George; Manios, Efstathios; Synetou, Margarita; Savvari, Paraskevi; Vemmou, Anastasia; Koromboki, Eleni; Saliaris, Michalis; Blanas, Konstantinos; Vemmos, Konstantinos

    2012-02-01

    Atrial fibrillation (AF) is a major factor for stroke and stroke-associated mortality, and its incidence is increasing during the last decades. There are only scarce data about its prevalence in Greece. We designed an epidemiological cross-sectional study to estimate the prevalence of AF in Greece and evaluate the adequacy of anticoagulant treatment in AF patients. The Arcadia Rural Study on Atrial Fibrillation (ARSAF) was conducted between 2002-2003 in five rural villages of the Arcadia province (Greece) with a permanent population of 1312 individuals. Patients had a thorough medical examination and electrocardiogram, and information was collected about their medical history and comorbidities. CHADS2 score was used to determine stroke risk for participants with AF. 1155 subjects (88% of the entire population) participated in the study. The overall prevalence of AF was 3.9% showing an increasing trend with increasing age ranging from 0.4% in patients 84 years. Among patients with AF, 14 (32%) had paroxysmal AF. The presence of AF was associated with increasing age (OR: 1.67 for every 10 years increase, 95% CI: 1.26-2.15), hypertension (OR: 2.12, 95% CI: 1.02-4.14), heart failure (OR: 11.85, 95% CI: 4.92-28.56) and prior cerebrovascular disease (OR: 4.17, 95% CI: 1.44-12.06). Among these subjects with AF, 12 (26.6%) were considered as low-risk (CHADS2 = 0), 18 (40.0%) as intermediate-risk (CHADS2 = 1), and 15 (33.3%) as high-risk (CHADS2 > 1) patients for stroke. 25 (55.5%) patients with AF did not receive appropriate antithrombotic treatment. The prevalence of AF in Greece is similar to other countries and increases with increasing age.

  10. Effect of Early Direct Current Cardioversion on the Recurrence of Atrial Fibrillation in Patients With Persistent Atrial Fibrillation

    DEFF Research Database (Denmark)

    Osmanagic, Armin; Möller, Sören; Osmanagic, Azra

    2015-01-01

    In patients with persistent atrial fibrillation (AF), the sinus rhythm (SR) can be restored by direct current cardioversion (DCC), although the recurrence of AF after successful DCC is common. We examined whether transesophageal echocardiography (TEE)-guided early DCC, compared with the conventio......In patients with persistent atrial fibrillation (AF), the sinus rhythm (SR) can be restored by direct current cardioversion (DCC), although the recurrence of AF after successful DCC is common. We examined whether transesophageal echocardiography (TEE)-guided early DCC, compared...... with persistent AF lasting >60 days. The recurrence-free survival probability at 28 days in patients with persistent AF

  11. COMBINED ECONOMIC AND EMISSION DISPATCH WITH AND WITHOUT CONSIDERING TRANSMISSION LOSS

    OpenAIRE

    Pratyush Das; Raju Patwary; S.C. Konar

    2013-01-01

    This paper gives a complete idea about the Combined Economic and Emission Dispatch (CEED) in different load demand. This paper shows CEED of a six generator system by neglecting the transmission loss first, and after that CEED of the same system considering transmission loss. Here we solve the CEED problem with the help of Mat-Lab software. The results are graphically represented here, like generation cost v/s load demands; load shared by each generator in different load demand...

  12. Association of serum chemerin concentrations with the presence of atrial fibrillation.

    Science.gov (United States)

    Zhang, Guowei; Xiao, Mochao; Zhang, Lili; Zhao, Yue; Yang, Qinghui

    2017-05-01

    Objective Chemerin, a newly discovered adipokine, is correlated with hypertension, diabetes and coronary heart disease. The aim of this study is to investigate the association of serum chemerin concentrations with the presence of atrial fibrillation. Methods Serum chemerin concentrations were determined in 256 patients with atrial fibrillation and 146 healthy subjects. Atrial fibrillation patients were then divided into paroxysmal, persistent and permanent atrial fibrillation. Results Serum chemerin concentrations were significantly higher in atrial fibrillation patients compared with healthy controls. In subgroup studies, patients with permanent atrial fibrillation had higher serum chemerin concentrations than those with persistent and paroxysmal atrial fibrillation. Furthermore, significant higher serum chemerin concentrations were observed in persistent atrial fibrillation patients compared with paroxysmal atrial fibrillation subjects. Serum chemerin concentrations were associated with the presence of atrial fibrillation after logistic regression analysis. Pearson correlation analysis revealed a positive relation of serum chemerin concentrations with body mass index, systolic blood pressure, diastolic blood pressure, triglycerides, low-density lipoprotein cholesterol, blood urea nitrogen, creatinine, C-reactive protein and left atrial diameter. Conclusion Serum chemerin concentrations are associated with the presence of atrial fibrillation and atrial remodelling.

  13. Mechanical Deformation Mechanisms and Properties of Prion Fibrils Probed by Atomistic Simulations

    Science.gov (United States)

    Choi, Bumjoon; Kim, Taehee; Ahn, Eue Soo; Lee, Sang Woo; Eom, Kilho

    2017-03-01

    Prion fibrils, which are a hallmark for neurodegenerative diseases, have recently been found to exhibit the structural diversity that governs disease pathology. Despite our recent finding concerning the role of the disease-specific structure of prion fibrils in determining their elastic properties, the mechanical deformation mechanisms and fracture properties of prion fibrils depending on their structures have not been fully characterized. In this work, we have studied the tensile deformation mechanisms of prion and non-prion amyloid fibrils by using steered molecular dynamics simulations. Our simulation results show that the elastic modulus of prion fibril, which is formed based on left-handed β-helical structure, is larger than that of non-prion fibril constructed based on right-handed β-helix. However, the mechanical toughness of prion fibril is found to be less than that of non-prion fibril, which indicates that infectious prion fibril is more fragile than non-infectious (non-prion) fibril. Our study sheds light on the role of the helical structure of amyloid fibrils, which is related to prion infectivity, in determining their mechanical deformation mechanisms and properties.

  14. [INTERACTION OF THE DYE CONGO RED WITH FIBRILS OF LYSOZYME, BETA2-MICROGLOBULIN AND TRANSTHYRETIN].

    Science.gov (United States)

    Antimonova, O I; Grudinina, N A; Egorov, V V; Polyakov, D S; Iljin, V V; Shavlovsky, M M

    2016-01-01

    By means of spectrophotometric assay we investigated interaction of the dye Congo red (CR) with fibrils of model proteins--hen egg white lysozyme, recombinant human beta2-microglobulin (b2M) and recombinant human transthyretin (TTR). The commercial dye sample was found to contain a significant amount of impurities. Methods for the dye purification are disclosed and CR molar extinction coefficient at 490 nm (ε490) was determined to be 3.3 x 10(4) M(-1) x cm(-1) at pH above 6.0. Formation of the CR-fibril complex results in changes in the dye visible absorption spectrum. According to the data on titration of fibril solutions with excess of the dye, CR binds to lysozyme fibrils at a ratio of about 5 molecules per protein monomer within fibril structure, to b2M fibrils--about 4 molecules per monomer, to TTR fibrils--about 4 molecules per subunit of the protein.

  15. Mechanical properties of human patellar tendon at the hierarchical levels of tendon and fibril

    DEFF Research Database (Denmark)

    Svensson, René B; Hansen, Philip; Hassenkam, Tue

    2012-01-01

    's modulus was 2.0 ± 0.5 GPa, and the toe region reached 3.3 ± 1.9% strain in whole patellar tendons. Based on dry cross-sectional area, the Young's modulus of isolated collagen fibrils was 2.8 ± 0.3 GPa, and the toe region reached 0.86 ± 0.08% strain. The measured fibril modulus was insufficient to account...... distinct collagen fibrils would display similar mechanical properties. Human patellar tendons (n = 5) were mechanically tested in vivo by ultrasonography. Biopsies were obtained from each tendon, and individual collagen fibrils were dissected and tested mechanically by atomic force microscopy. The Young...... for the modulus of the tendon in vivo when fibril content in the tendon was accounted for. Thus, our original hypothesis was not supported, although the in vitro fibril modulus corresponded well with reported in vitro tendon values. This correspondence together with the fibril modulus not being greater than...

  16. Radio Frequency Power Load and Associated Method

    Science.gov (United States)

    Srinivasan, V. Karthik (Inventor); Freestone, Todd M. (Inventor); Sims, William Herbert, III (Inventor)

    2014-01-01

    A radio frequency power load and associated method. A radio frequency power load apparatus may include a container with an ionized fluid therein. The apparatus may include one conductor immersed in a fluid and another conductor electrically connected to the container. A radio frequency transmission system may include a radio frequency transmitter, a radio frequency amplifier connected to the transmitter and a radio frequency power load apparatus connected to the amplifier. The apparatus may include a fluid having an ion source therein, one conductor immersed in a fluid, and another conductor electrically connected to the container. A method of dissipating power generated by a radio frequency transmission system may include constructing a waveguide with ionized fluid in a container and connecting the waveguide to an amplifier of the transmission system.

  17. Power flow studies in HVAC and HVDC transmission lines

    Energy Technology Data Exchange (ETDEWEB)

    Oyedokun, D.T.; Folly, K.A. [Cape Town Univ. (South Africa). Dept. of Electrical Engineering

    2008-07-01

    Flexible AC transmission system (FACTS) devices, additional high voltage AC (HVAC) lines, and additional HVDC transmission lines can all be used to increase the capacity of transmission infrastructure. In this paper, 3 case studies were presented to evaluate the different technologies. Power flow analyses were conducted in order to determine the most feasible method of increasing capacity. A 35 per cent increase in load demand was considered in relation to changes in power flow, rotor angle, loading, and reactive power compensation. The study showed that DC limits were reduced at the rectifier substation, and more power was routed via the HVAC line while less power was routed via the HVDC line. A comparison of the case studies showed that using an HVAC transmission line in parallel with an additional HVAC line was the most suitable method of increasing transmission infrastructure. Transmission losses for the double circuit HVAC lines were approximately 60 MW. 13 refs., 6 tabs., 6 figs.

  18. Amyloid fibril systems reduce, stabilize and deliver bioavailable nanosized iron

    Science.gov (United States)

    Shen, Yi; Posavec, Lidija; Bolisetty, Sreenath; Hilty, Florentine M.; Nyström, Gustav; Kohlbrecher, Joachim; Hilbe, Monika; Rossi, Antonella; Baumgartner, Jeannine; Zimmermann, Michael B.; Mezzenga, Raffaele

    2017-07-01

    Iron-deficiency anaemia (IDA) is a major global public health problem. A sustainable and cost-effective strategy to reduce IDA is iron fortification of foods, but the most bioavailable fortificants cause adverse organoleptic changes in foods. Iron nanoparticles are a promising solution in food matrices, although their tendency to oxidize and rapidly aggregate in solution severely limits their use in fortification. Amyloid fibrils are protein aggregates initially known for their association with neurodegenerative disorders, but recently described in the context of biological functions in living organisms and emerging as unique biomaterial building blocks. Here, we show an original application for these protein fibrils as efficient carriers for iron fortification. We use biodegradable amyloid fibrils from β-lactoglobulin, an inexpensive milk protein with natural reducing effects, as anti-oxidizing nanocarriers and colloidal stabilizers for iron nanoparticles. The resulting hybrid material forms a stable protein-iron colloidal dispersion that undergoes rapid dissolution and releases iron ions during acidic and enzymatic in vitro digestion. Importantly, this hybrid shows high in vivo iron bioavailability, equivalent to ferrous sulfate in haemoglobin-repletion and stable-isotope studies in rats, but with reduced organoleptic changes in foods. Feeding the rats with these hybrid materials did not result in abnormal iron accumulation in any organs, or changes in whole blood glutathione concentrations, inferring their primary safety. Therefore, these iron-amyloid fibril hybrids emerge as novel, highly effective delivery systems for iron in both solid and liquid matrices.

  19. Comparative study of atrial fibrillation and AV conduction in mammals

    NARCIS (Netherlands)

    Meijler, F.L.; Tweel, I. van der

    1987-01-01

    Atrial fibrillation is one ofthe most common cardiac arrhythmias in humans. It a1so occurs quite frequent1y in dogs and horses. Comparative study of this arrhythmia may contribute to better understanding of the pathophysiologica1 mechanisms involved. In this study, we present a quantitative

  20. Quantifying Time in Atrial Fibrillation and the Need for Anticoagulation

    DEFF Research Database (Denmark)

    Miyazawa, Kazuo; Pastori, Daniele; Lip, Gregory Y H

    2017-01-01

    Atrial fibrillation (AF) is one of the major cardiovascular diseases, and the number of patients with AF is predicted to increase markedly in the coming years. Despite recent advance in management of patients with AF, AF remains one of the main causes of stroke or systemic embolism. Application o...

  1. Ganglion Plexus Ablation in Advanced Atrial Fibrillation: The AFACT Study

    NARCIS (Netherlands)

    Driessen, Antoine H. G.; Berger, Wouter R.; Krul, Sébastien P. J.; van den Berg, Nicoline W. E.; Neefs, Jolien; Piersma, Femke R.; Chan Pin Yin, Dean R. P. P.; de Jong, Jonas S. S. G.; van Boven, WimJan P.; de Groot, Joris R.

    2016-01-01

    Patients with long duration of atrial fibrillation (AF), enlarged atria, or failed catheter ablation have advanced AF and may require more extensive treatment than pulmonary vein isolation. The aim of this study was to investigate the efficacy and safety of additional ganglion plexus (GP) ablation

  2. Aggregation properties of a short peptide that mediates amyloid fibril ...

    Indian Academy of Sciences (India)

    Short peptides have been identified from amyloidogenic proteins that form amyloid fibrils in isolation. The hexapeptide stretch 21DIDLHL26 has been shown to be important in the self-assembly of the Src homology 3 (SH3) domain of p85 subunit of bovine phosphatidylinositol-3-kinase (PI3-SH3). The SH3 domain of ...

  3. Detection of paroxysmal atrial fibrillation in acute stroke patients

    NARCIS (Netherlands)

    Rizos, T.; Rasch, C.; Jenetzky, E.; Hametner, C.; Kathoefer, S.; Reinhardt, R.; Hepp, T.; Hacke, W.; Veltkamp, R.

    2010-01-01

    Atrial fibrillation (AF) is a frequent cause of stroke, but detecting paroxysmal AF (pAF) poses a challenge. We investigated whether continuous bedside ECG monitoring in a stroke unit detects pAF more sensitively than 24-hour Holter ECG, and tested whether examining RR interval dynamics on

  4. Edoxaban versus warfarin in patients with atrial fibrillation

    DEFF Research Database (Denmark)

    Giugliano, Robert P; Ruff, Christian T; Braunwald, Eugene

    2013-01-01

    BACKGROUND: Edoxaban is a direct oral factor Xa inhibitor with proven antithrombotic effects. The long-term efficacy and safety of edoxaban as compared with warfarin in patients with atrial fibrillation is not known. METHODS: We conducted a randomized, double-blind, double-dummy trial comparing t...

  5. Managing atrial fibrillation in the elderly: critical appraisal of dronedarone

    Directory of Open Access Journals (Sweden)

    Trigo P

    2011-12-01

    Full Text Available Paula Trigo, Gregory W FischerDepartment of Anesthesiology, Mount Sinai School of Medicine, New York, NY, USAAbstract: Atrial fibrillation is the most commonly seen arrhythmia in the geriatric population and is associated with increased cardiovascular morbidity and mortality. Treatment of the elderly with atrial fibrillation remains challenging for physicians, because this unique subpopulation is characterized by multiple comorbidities requiring chronic use of numerous medications, which can potentially lead to severe drug interactions. Furthermore, age-related changes in the cardiovascular system as well as other physiological changes result in altered drug pharmacokinetics. Dronedarone is a new drug recently approved for the treatment of arrhythmias, such as atrial fibrillation and/or atrial flutter. Dronedarone is a benzofuran amiodarone analog which lacks the iodine moiety and contains a methane sulfonyl group that decreases its lipophilicity. These differences in chemical structure are responsible for making dronedarone less toxic than amiodarone which, in turn, results in fewer side effects. Adverse events for dronedarone include gastrointestinal side effects and rash. No dosage adjustments are required for patients with renal impairment. However, the use of dronedarone is contraindicated in the presence of severe hepatic dysfunction.Keywords: atrial fibrillation, elderly, antiarrhythmic agents, amiodarone, dronedarone

  6. Antithrombotic therapy in atrial fibrillation associated with valvular heart disease

    DEFF Research Database (Denmark)

    Lip, Gregory Y H; Collet, Jean Philippe; Caterina, Raffaele de

    2017-01-01

    Atrial fibrillation (AF) is a major worldwide public health problem, and AF in association with valvular heart disease (VHD) is also common. However, management strategies for this group of patients have been less informed by randomized trials, which have largely focused on 'non-valvular AF' pati...

  7. Cancer antigen-125 and risk of atrial fibrillation

    DEFF Research Database (Denmark)

    Cheung, Angel; Gong, Mengqi; Bellanti, Roberto

    2018-01-01

    Background: Cancer antigen-125 (Ca-125) is traditionally recognised as a tumour marker and its role in cardiovascular diseases has been studied only in recent years. Whether Ca-125 is elevated in patients with atrial fibrillation (AF) and its levels predict the risk of AF remains controversial. T...

  8. Quinidine-induced ventricular flutter and fibrillation without digitalis therapy

    NARCIS (Netherlands)

    Koster, R. W.; Wellens, H. J.

    1976-01-01

    Three cases are described with documented ventricular flutter and fibrillation during quinidine medication without concomitant digitalis therapy. In all three patients the arrhythmia developed while they were receiving moderate doses of quinidine. Although no changes in QRS width were observed after

  9. Cardiac ion channels and mechanisms for protection against atrial fibrillation

    DEFF Research Database (Denmark)

    Grunnet, Morten; Bentzen, Bo Hjorth; Sørensen, Ulrik S

    2011-01-01

    Atrial fibrillation (AF) is recognised as the most common sustained cardiac arrhythmia in clinical practice. Ongoing drug development is aiming at obtaining atrial specific effects in order to prevent pro-arrhythmic, devastating ventricular effects. In principle, this is possible due to a different...

  10. Dabigatran versus warfarin in patients with atrial fibrillation

    NARCIS (Netherlands)

    Connolly, Stuart J.; Ezekowitz, Michael D.; Yusuf, Salim; Eikelboom, John; Oldgren, Jonas; Parekh, Amit; Pogue, Janice; Reilly, Paul A.; Themeles, Ellison; Varrone, Jeanne; Wang, Susan; Alings, Marco; Xavier, Denis; Zhu, Jun; Diaz, Rafael; Lewis, Basil S.; Darius, Harald; Diener, Hans-Christoph; Joyner, Campbell D.; Wallentin, Lars; Connolly, S. J.; Ezekowitz, M. D.; Yusuf, S.; Eikelboom, J.; Oldgren, J.; Parekh, A.; Reilly, P. A.; Themeles, E.; Varrone, J.; Wang, S.; Palmcrantz-Graf, E.; Haehl, M.; Wallentin, L.; Alings, A. M. W.; Amerena, J. V.; Avezum, A.; Baumgartner, I.; Brugada, J.; Budaj, A.; Caicedo, V.; Ceremuzynski, L.; Chen, J. H.; Commerford, P. J.; Dans, A. L.; Darius, H.; Di Pasquale, G.; Diaz, R.; Erol, C.; Ferreira, J.; Flaker, G. C.; Flather, M. D.; Franzosi, M. G.; Gamboa, R.; Golitsyn, S. P.; Gonzalez Hermosillo, J. A.; Halon, D.; Heidbuchel, H.; Hohnloser, S. H.; Hori, M.; Huber, K.; Jansky, P.; Kamensky, G.; Keltai, M.; Kim, S.; Lau, C. P.; Le Heuzey, J. Y. F.; Lewis, B. S.; Liu, L. S.; Nanas, J.; Razali, O.; Pais, P. S.; Parkhomenko, A. N.; Pedersen, K. E.; Piegas, L. S.; Raev, D.; Simmers, T. A.; Smith, P. J.; Talajic, M.; Tan, R. S.; Tanomsup, S.; Toivonen, L.; Vinereanu, D.; Xavier, D.; Zhu, J.; Diener, H. C.; Joyner, C. D.; Diehl, A.; Ford, G.; Robinson, M.; Silva, J.; Sleight, P.; Wyse, D. G.; Collier, J.; de Mets, D.; Hirsh, J.; Lesaffre, E.; Ryden, L.; Sandercock, P.; Anastasiou-Nana, M. I.; Andersen, G.; Annex, B. H.; Atra, M.; Bornstein, N. M.; Boysen, G.; Brouwers, P. J. A. M.; Buerke, M.; Burrell, L. M.; Chan, Y. K.; Chen, W. H.; Cheung, R. T. F.; Divakaramenon, S.; Donnan, G. A.; Duray, G. Z.; Dvorakova, H.; Fiedler, J.; Gardinale, E.; Gates, P. C.; Goshev, E. G.; Goto, S.; Gross, B.; Guimaraes, H. P.; Gulkevych, O.; Haberl, R. L.; Hankey, G.; Hartikainen, J.; Healey, J.; Iliesiu, A. M.; Irkin, O.; Jaxa-Chamiec, T.; Jolly, S.; Kaste, K. A. M.; Kies, B.; Kostov, K. D.; Kristensen, K. S.; Labovitz, A. J.; Lassila, R. P. T.; Lee, K. L. F.; Lutay, Y. M.; Magloire, P.; Mak, K. H.; Meijer, A.; Mihov, L.; Morillo, C. A.; Morillo, L. E.; Nair, G. M.; Norrving, B.; Ntalianis, A.; Ntsekhe, M.; Olah, L.; Pasco, P. M. D.; Peeters, A.; Perovic, V.; Petrov, I.; Pizzolato, G.; Rafti, F.; Rey, N. R.; Ribas, S.; Rokoss, M.; Sarembock, I. J.; Sheth, T.; Shuaib, A.; Sitkei, E.; Sorokin, E.; Srámek, M.; Strozynska, E.; Tanne, D.; Thijs, V. N. S.; Tomek, A.; Turazza, F.; Vanhooren, G.; Vizel, S. A.; Vos, J.; Wahlgren, N.; Weachter, R.; Zaborska, B.; Zaborski, J.; Zimlichman, R.; Cong, J.; Fendt, K.; Muldoon, S.; Bajkor, S.; Grinvalds, A.; Malvaso, M.; Pogue, J.; Simek, K.; Yang, S.; Alzogaray, M. F.; Bono, J. O.; Caccavo, A.; Cartasegna, L.; Casali, W. P.; Cuello, J. L.; Cuneo, C. A.; Elizari, M. V.; Fernandez, A. A.; Ferrari, A. E.; Gabito, A. J.; Goicoechea, R. F.; Gorosito, V. M.; Hirschson, A.; Hominal, M. A.; Hrabar, A. D.; Liberman, A.; Mackinnon, I. J.; Manzano, R. D.; Muratore, C. A.; Nemi, S. A.; Rodriguez, M. A.; Sanchez, A. S.; Secchi, J.; Vogel, D. R.; Colquhoun, D. M.; Crimmins, D. S.; Dart, A. M.; Davis, S. M.; Hand, P. J.; Kubler, P. A.; Lehman, R. G.; McBain, G.; Morrison, H. C.; New, G.; Singh, B. B.; Spence, C. Z.; Waites, J. H.; Auer, J.; Doweik, L.; Freihoff, F.; Gaul, G.; Gazo, F.; Geiger, H.; Giacomini, G.; Huber, G. W.; Jukic, I.; Lamm, G.; Niessner, H.; Podczeck, A.; Schuh, J.; Siostrzonek, P.; Steger, C.; Vogel, B.; Watzak, R.; Weber, H. S.; Weihs, W.; Blankoff, I.; Boland, J. L.; Brike, C.; Carlier, M.; Cools, F.; de Meester, A.; de Raedt, H. J.; de Wolf, L.; Dhooghe, G. M.; Dilling-Boer, D.; Elshot, S. R.; Fasseaux, S.; Goethals, M.; Goethals, P.; Gurne, O.; Hellemans, S.; Ivan, B.; Jottrand, M.; Kersschot, I.; Lecoq, E.; Marcovitch, O.; Melon, D.; Miljoen, H.; Missault, L.; Pierard, L. A.; Provenier, F.; Rousseau, M. F.; Stockman, D.; Tran-Ngoc, E.; van Mieghem, W.; Vandekerckhove, Y.; Vandervoort, P.; Verrostte, J.; Vijgen, J.; Armaganijan, D.; Braga, C.; Braga, J. C. F.; Cipullo, R.; Cunha, C. L. P.; de Paola, A.; Delmonaco, M. I.; Guimaraes, F. V.; Herek, L.; Kerr Saraiva, J. F.; Maia, L. N.; Lorga, A. M.; Lorga-Filho, A. M.; Marino, R. L.; Melo, C. S.; Mouco, O. M.; Pereira, V. C.; Precoma, D. B.; Rabelo, W.; Rassi, S.; Rossi, P. R.; Rossi Neto, J. M.; Silva, F. M.; Vidotti, M. H.; Zimmermann, S. L.; Anev, E. D.; Balabanov, T. A.; Baldjiev, E. S.; Bogusheva, E. S.; Chaneva, M. A.; Filibev, I. G.; Gotcheva, N. N.; Goudev, A. R.; Gruev, I. T.; Guenova, D. T.; Kamenova, Z. A.; Manov, E. I.; Panov, I. A.; Parvanova, Z. I.; Pehlivanova, M. B.; Penchev, P. T.; Penkov, N. Y.; Radoslavov, A. L.; Ramshev, K. N.; Runev, N. M.; Sindzhielieva, M. N.; Spirova, D. A.; Tsanova, V. M.; Tzekova, M. L.; Yaramov, G. K.; Aggarwal, R.; Bakbak, A. I.; Bayly, K.; Berlingieri, J. C.; Blackburn, K.; Bobbie, C.; Booth, A. W.; Borts, D.; Bose, S.; Boucher, P.; Brown, K.; Burstein, J. M.; Butt, J. C.; Carlson, B. D.; Chetty, R.; Chiasson, J. D.; Constance, C.; Costi, P.; Coutu, B.; Deneufbourg, I.; Dion, D.; Dorian, P.; Douketis, J. D.; Farukh, S.; Filipchuk, N. G.; Fox, B. A.; Fox, H. I.; Gailey, C. B.; Gauthier, M.; Glanz, A.; Green, M. S.; Habot, J.; Hink, H.; Kearon, C.; Kouz, S.; Lai, C.; Lai, K.; Lalani, A. V.; Lam, A. S.; Lapointe, L. A.; Leather, R. A.; Ma, P. T. S.; MacKay, E.; Mangat, I.; Mansour, S.; Melton, E.; Mitchell, L. B.; Morris, A. L.; Nisker, W. A.; O'Donnell, M. J.; O'Hara, G.; Omichinski, L. M.; Pandey, A. S.; Parkash, R.; Pesant, Y.; Pilon, C.; Pistawka, K. J.; Powell, C. N.; Price, J. B.; Prieur, S.; Rebane, T. M.; Ricci, A. J.; Roberge, J.; Roy, M.; Sapp, J. L.; Savard, D.; Schulman, S.; Sehl, M. J.; Sestier, F.; Shandera, R.; Shu, D.; Sterns, L. D.; St-Hilaire, R.; Syan, G. S.; Talbot, P.; Teitelbaum, I.; Tytus, R. H.; Winkler, L.; Zadra, R.; Zidel, B. S.; Bai, X. J.; Gao, W.; Gao, X.; Guan, D. M.; He, Z. S.; Hua, Q.; Li, H.; Li, L.; Li, W. M.; Lu, G. P.; Lv, S.; Meng, K.; Niu, H. Y.; Qi, D. G.; Qi, S. Y.; Qian, F.; Sun, N. L.; Wang, H. Y.; Wang, N. F.; Yang, Y. M.; Zeng, H.; Zhang, F.; Zhang, F. R.; Zhang, L.; Bohorquez, R.; Rosas, J. F.; Saent, L.; Vacca, M.; Velasco, V. M.; Belohlavek, J.; Cernohous, M.; Choura, M.; Dedek, V.; Filipensky, B.; Hemzsky, L.; Karel, I.; Kopeckova, I.; Kovarova, K.; Labrova, R.; Madr, T.; Poklopova, Z.; Rucka, D.; Simon, J.; Skalicka, H.; Smidova, M.; Spinar, J.; Dodt, K. K.; Egstrup, K.; Friberg, J.; Haar, D.; Husted, S.; Jensen, G. V.; Joensen, A. M.; Klarlund, K. K.; Lind Rasmussen, S.; Melchior, T. M.; Olsen, M. E.; Poulsen, M. K.; Ralfkiaer, N.; Rasmussen, L. H.; Skagen, K.; Airaksinen, K. E.; Huikuri, H. V.; Hussi, E. J.; Kettunen, P.; Mänttäri, M.; Melin, J. H.; Mikkelsson, J.; Peuhkurinen, K.; Virtanen, V. K.; Ylitalo, A.; Agraou, B.; Boucher, L.; Bouvier, J. M.; Boye, A.; Boye, B.; Decoulx, E. 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S.; Orfanidis, Z.; Papamichalis, M.; Peltekis, L.; Savvas, S.; Skoumpourdis, E. A.; Stakos, D. A.; Styliadis, I.; Triposkiadis, F.; Tsounis, D.; Tziakas, D. N.; Zafiridis, T.; Zarifis, J. H.; Chan, G. C. P.; Chan, W. K.; Chan, W. S.; Lau, C. L.; Tse, H. F.; Tsui, P. T.; Yu, C. M.; Yue, C. S.; Fugedi, K.; Garai, B.; Jánosi, A.; Kadar, A.; Karpati, P.; Keltai, K.; Kosa, I.; Kovacs, I.; Laszlo, Z.; Mezei, L.; Rapi, J.; Regos, L. I.; Szakal, I.; Szigyarto, I.; Toth, K.; Zsa'ry, A.; Agarwal, D. K.; Aggarwal, R. K.; Arulvenkatesh, R.; Bharani, A.; Bhuvaneswaran, J. S.; Byrapaneni, R. B.; Chandwani, P.; Chopra, S.; Desai, N.; Deshpande, V.; Golla, N. P.; Gupta, J. B.; Haridas, K. K.; Hiremath, J.; Jain, A. S.; Jain, M.; Jhala, D. A.; Joseph, J.; Kaila, M.; Kannaiyan, A.; Kumar, S.; Kuruvila, P.; Mahorkar, V. K.; Metha, A.; Naik, A. M.; Narayanan, S.; Panwar, R. B.; Reddy, C.; Sawhney, J. P. S.; Shah, S. M.; Sharma, S.; Shetty, G. S.; Sinha, N.; Sontakke, N. N.; Srinivas, A.; Trivedi, M. 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D.; Kenton, D. M.; Kettunen, J. A.; Khan, M. A.; Khant, R. N.; Kirkwood, M. D.; Knight, B. P.; Knight, P. O.; Knutson, T. J.; Kobayashi, J. F.; Kogan, A.; Kogan, A. D.; Koren, M. J.; Kosinski, E. J.; Kosolcharoen, P.; Kostis, J. B.; Kramer, J. H.; Kramer, S. D.; Kron, J.; Kuchenrither, C. R.; Kulback, S. J.; Kumar, A.; Kushner, D.; Kutscher, A.; Lai, C. K.; Lam, J. B.; Landau, C.; Landzberg, J. S.; Lang, D. T.; Lang, J. M.; Lanzarotti, C. J.; Lascewski, D. L.; Lau, T. K.; Lee, J. K.; Lee, S.; Leimbach, W. N.; LePine, A. M.; Lesser, M. F.; Leuchak, S. H.; Levy, R. M.; Lewis, W. R.; Lincoln, T. L.; Lingerfelt, W. M.; Liston, M.; Liu, Z. G.; Lloret, R. L.; Lohrbauer, L.; Longoria, D. C.; Lott, B. M.; Louder, D. R.; Loukinen, K. L.; Lovell, J.; Lue, S.; Mackall, J. A.; Maletz, L.; Marlow, L.; Martin, R. C.; Matsumura, M.; McCartney, M. J.; McDuffie, D.; McGough, M. F.; McGrew, F. A.; McGuinn, Wm P.; McMillen, M. D.; McNeff, J.; McPherson, C. A.; Meengs, M. E.; Meengs, W. L.; Meholick, A. W.; Meisner, J. S.; Melucci, M. B.; Mercando, A.; Merlino, J. D.; Meymandi, S. K.; Miele, M. B.; Miller, R. H.; Miller, S. H.; Minor, S. T.; Mitchell, M. R.; Modi, M.; Mody, F. V.; Moeller, C. L.; Moloney, J. F.; Moran, J. E.; Morcos, N. C.; Morgan, A.; Mukherjee, S. K.; Mullinax, K.; Murphy, A. L.; Mustin, A. J.; Myers, G. I.; Naccarelli, G. V.; Nadar, V. K.; Nallasivan, M.; Navas, J. P.; Niazi, I. K.; Nsah, E. N.; Nunamaker, J. L.; Ochalek, T. B.; O'dea, D. J.; Ogilvie, P. D.; Olliff, B.; Omalley, A. K.; O'Neill, P. G.; Onufer, J. R.; Orchard, R. C.; Orihuela, L. A.; Ortiz, E. C.; O'Sullivan, M. T.; Padanilam, B. J.; Pandey, P.; Patel, D. V.; Patel, R. J.; Patel, V. B.; Patlola, R. R.; Pennock, G. D.; Perlman, R.; Peters, P. H.; Petrillo, A. V.; Pezzella, S.; Phillips, D.; Pierre-Louis, J. R.; Pilcher, G.; Pillai, C.; Pollock, S. G.; Pond, M. S.; Porterfield, J. K.; Presant, L.; Pressler, J.; Pribble, A. H.; Promisloff, S. D.; Pudi, K. K.; Putnam, D. L.; Quartner, J.; Quinn, J. C.; Quinnell, C. M.; Raad, G. L.; Rasmussen, L. A.; Ray, C.; Reiffel, J. A.; Reynertson, S.; Richardson, J. W.; Riley, C. P.; Rippy, J. S.; Rittelmeyer, J. T.; Roberts, D. M.; Robertson, R.; Robinson, V. J. B.; Rocco, T. A.; Rosenbaum, D.; Roth, E. M.; Rottman, J. N.; Rough, R. R.; Rubenstein, J. J.; Sakkal, A. M.; Saleem, T.; Salerno, D. M.; Samendinger, M. L.; Sandeno, S.; Santilli, T. M.; Santucci, P.; Sattar, P.; Saxman, K. A.; Schaefer, S.; Schmidt, J.; Schneider, R. M.; Schocken, D. D.; Schrader, M. K.; Schramm, B. A.; Schultz, R. W.; Schussheim, A. E.; Schwarz, E. F.; Seamon, M. C.; Sestero, J. D.; Shah, M. P.; Shah, R.; Shalaby, A.; Shanes, J. G.; Sheftel, G. L.; Sheikh, K. H.; Shein, A. B.; Shemonsky, N. K.; Shepler, A.; Sheridan, E.; Shipwash, T. M.; Shopnick, R. I.; Short, W. G.; Shoukfeh, M. F.; Sibia, R. S.; Siler, T. M.; Silva, J. A.; Simons, G. R.; Simpson, A. G.; Simpson, H. R.; Simpson, V. J.; Singh, B. N.; Singh, N.; Singh, V. N.; Sitz, C. J.; Skatrud, L.; Sklar, J.; Slotwiner, D. J.; Smith, P. F.; Smith, P. N.; Smith, R. H.; Smith, J. E.; Sodowick, B. C.; Solomon, A. J.; Soltero, E. A.; Sonel, A. F.; Sperling, R.; Spiller, C.; Spink, B. Z.; Sprinkle, L. W.; Spyropoulos, A. C.; Stamos, T. D.; Steljes, A. D.; Stillabower, M. E.; Stover, T.; Strain, J. E.; Strickland, T. L.; Suresh, D. P.; Takata, T. S.; Taylor, J. S.; Taylor, M.; Teague, S. M.; Teixeia, J. M.; Telfer, E. A.; Terry, P. S.; Terry, R. W.; Thai, H. M.; Thalin, M.; Thomas, V. N.; Thompson, C. A.; Thompson, M. A.; Thornton, J. W.; Tidman, R. E.; Toler, B. S.; Traina, M. I.; Trippi, J. A.; Ujiiye, D. L.; Usedom, J. E.; van de Graaff, E.; van de Wall, L. R.; Vaughn, J. W.; Ver Steeg, D.; Vicari, R. M.; Vijay, N.; Vitale, C. B.; Vlastaris, A. G.; Voda, J.; Vora, K. N.; Voyles, W. F.; Vranian, R. B.; Vrooman, P. S.; Waack, P.; Waldo, A. L.; Walker, J. L.; Wallace, M. A.; Walsh, E. A.; Walsh, R. L.; Walton, A.; Washam, M.; Wehner, P. S.; Wei, J. Y.; Weiner, S.; Weiss, R. J.; Wells, D. M.; Wera-Archakul, W.; Wertheimer, J. H.; West, S. A.; Whitaker, J. H.; White, M. L.; White, R. H.; Whitehill, J. N.; Wiegman, P. J.; Wiesel, J.; Williams, J.; Williams, L. E.; Williams, M. L.; Williamson, V. K.; Wilson, V. E.; Wilson, W. W.; Woodfield, S. L.; Wulff, C. W.; Yates, S. W.; Yousuf, K. A.; Zakhary, B. G.; Zambrano, R.; Zimetbaum, P.; Zoble, R.; Zopo, A. R.; Zwerner, P. L.

    2009-01-01

    BACKGROUND: Warfarin reduces the risk of stroke in patients with atrial fibrillation but increases the risk of hemorrhage and is difficult to use. Dabigatran is a new oral direct thrombin inhibitor. METHODS: In this noninferiority trial, we randomly assigned 18,113 patients who had atrial

  11. MRI screening for chronic anticoagulation in atrial fibrillation

    Directory of Open Access Journals (Sweden)

    Mark eFisher

    2013-10-01

    Full Text Available Anticoagulation is highly effective in preventing stroke due to atrial fibrillation, but numerous studies have demonstrated low utilization of anticoagulation for these patients. Assessment of clinicians’ attitudes on this topic indicate that fear of intracerebral hemorrhage (ICH, rather than appreciation of anticoagulant benefits, largely drives clinical decision-making for treatment with anticoagulation in atrial fibrillation. Risk stratification strategies have been used for anticoagulation benefits and hemorrhage risk, but ICH is not specifically addressed in the commonly used hemorrhage risk stratification systems. Cerebral microbleeds are cerebral microscopic hemorrhages demonstrable by brain MRI, indicative of prior microhemorrhages, and predictive of future risk of ICH. Prevalence of cerebral microbleeds increases with age; and cross-sectional and limited prospective studies generally indicate that microbleeds confer substantial risk of ICH in patients treated with chronic anticoagulation. MRI thus is a readily available and appealing modality that can directly assess risk of future ICH in patients receiving anticoagulants for atrial fibrillation. Incorporation of MRI into routine practice is, however, fraught with difficulties, including the uncertain relationship between number and location of microbleeds and ICH risk, as well as cost-effectiveness of MRI. A proposed algorithm is provided, and relevant advantages and disadvantages are discussed. At present, MRI screening appears most appropriate for a subset of atrial fibrillation patients, such as those with intermediate stroke risk, and may provide reassurance for clinicians whose concerns for ICH tend to outweigh benefits of anticoagulation.

  12. Abnormal atrial activation in young patients with lone atrial fibrillation

    DEFF Research Database (Denmark)

    Holmqvist, Fredrik; Olesen, Morten S; Tveit, Arnljot

    2011-01-01

    Aims Patients with a history of atrial fibrillation (AF) have previously been shown to have altered atrial conduction, as seen non-invasively using signal-averaged P-wave analysis. However, little is known about the P-wave morphology in patients in the early phases of AF with structurally normal ...

  13. Atrial Fibrillation in Lusaka – Pathoaetiology, Pathophysiology and ...

    African Journals Online (AJOL)

    Background: Atrial Fibrillation (AF) is the commonest sustained arrhythmia the world over and is associated with substantial morbidity and mortality. An excessive ventricular rate, a loss of atrial contraction and an irregular ventricular filling time are the hallmark of this condition and all have negative clinical consequences.

  14. Atrial fibrillation: Therapeutic potential of atrial K+channel blockers.

    Science.gov (United States)

    Ravens, Ursula; Odening, Katja E

    2017-08-01

    Despite the epidemiological scale of atrial fibrillation, current treatment strategies are of limited efficacy and safety. Ideally, novel drugs should specifically correct the pathophysiological mechanisms responsible for atrial fibrillation with no other cardiac or extracardiac actions. Atrial-selective drugs are directed toward cellular targets with sufficiently different characteristics in atria and ventricles to modify only atrial function. Several potassium (K + ) channels with either predominant expression in atria or distinct electrophysiological properties in atria and ventricles can serve as atrial-selective drug targets. These channels include the ultra-rapidly activating, delayed outward-rectifying Kv1.5 channel conducting I Kur , the acetylcholine-activated inward-rectifying Kir3.1/Kir3.4 channel conducting I K,ACh , the Ca 2+ -activated K + channels of small conductance (SK) conducting I SK , and the two pore domain K + (K2P) channels TWIK-1, TASK-1 and TASK-3 that are responsible for voltage-independent background currents I TWIK-1 , I TASK-1 , and I TASK-3 . Here, we briefly review the characteristics of these K + channels and their roles in atrial fibrillation. The antiarrhythmic potential of drugs targeting the described channels is discussed as well as their putative value in treatment of atrial fibrillation. Copyright © 2016 Elsevier Inc. All rights reserved.

  15. Paroxysmal Atrial Fibrillation in a Mission-Assigned Astronaut

    Science.gov (United States)

    Bauer, Peter A.; Polk, J. D.

    2010-01-01

    This presentation will explore the clinical and administrative conundrums faced by the flight surgeon upon discovering asymptomatic paroxysmal atrial fibrillation seven months prior to scheduled long duration spaceflight. The presenter will discuss the decision-making process as well as the clinical and operational outcomes.

  16. Atrial Fibrillation in Embolic Stroke: Anticoagulant Therapy at UNTH ...

    African Journals Online (AJOL)

    Objective: The decision to commence anticoagulation in a patient with embolic stroke and atrial fibrillation (AF) is often a difficult one for many clinicians. The result can have significant impact on the patient. This study was therefore undertaken to review the use of anticoagulation in embolic stroke in the setting of atrial ...

  17. Outcome parameters for trials in atrial fibrillation: executive summary

    NARCIS (Netherlands)

    Kirchhof, Paulus; Auricchio, Angelo; Bax, Jeroen; Crijns, Harry; Camm, John; Diener, Hans-Christoph; Goette, Andreas; Hindricks, Gerd; Hohnloser, Stefan; Kappenberger, Lukas; Kuck, Karl-Heinz; Lip, Gregory Y. H.; Olsson, Bertil; Meinertz, Thomas; Priori, Silvia; Ravens, Ursula; Steinbeck, Gerhard; Svernhage, Elisabeth; Tijssen, Jan; Vincent, Alphons; Breithardt, Günter

    2007-01-01

    Atrial fibrillation (AF), the most common atrial arrhythmia, has a complex aetiology and causes relevant morbidity and mortality due to different mechanisms, including but not limited to stroke, heart failure, and tachy- or bradyarrhythmia. Current therapeutic options (rate control, rhythm control,

  18. Effect of Mechanical Stretching of the Skin on Collagen Fibril ...

    African Journals Online (AJOL)

    Dell

    It was recently established that, deformation of connective tissue cells under the influence of mechanical stretching intensifies the synthesis of structural biopolymers, particularly those of the collagen molecules, which are capable of associating into fibrils by self assembly (Buschmann et al., 1995,. Garbuzenko et al., 1997; ...

  19. The atrial fibrillation knowledge scale : Development, validation and results

    NARCIS (Netherlands)

    Hendriks, J.M.L.; Crijns, H.J.G.M.; Tieleman, R.G.; Vrijhoef, H.J.M.

    2013-01-01

    Background Patients' understanding of the nature and consequences of atrial fibrillation (AF) and appropriate therapy, is essential to optimize AF management. Currently, no valid instrument exists to measure knowledge in AF patients with a combined focus on disease, symptom recognition and therapy.

  20. Frequency analysis of the ECG before and during ventricular fibrillation

    NARCIS (Netherlands)

    Herbschleb, J.N.; Heethaar, R.M.; Tweel, I. van der; Meijler, F.L.

    1980-01-01

    Frequency analysis of cardiac electrograms of dogs with ventricular fibrillation (VF) during complete cardiopulmonary bypass and coronary perfusion showed a power spectrum with a peak around 12 Hz and its higher harmonics, suggesting more organization than generally assumed. As a next step to see

  1. Interplay between Folding and Assembly of Fibril-Forming Polypeptides

    NARCIS (Netherlands)

    Ni, R.; Abeln, S.; Schor, M.; Cohen Stuart, M.A.; Bolhuis, P.G.

    2013-01-01

    Polypeptides can self-assemble into hierarchically organized fibrils consisting of a stack of individually folded polypeptides driven together by hydrophobic interaction. Using a coarse-grained model, we systematically studied this self-assembly as a function of temperature and hydrophobicity of the

  2. Edoxaban versus Warfarin in Patients with Atrial Fibrillation

    NARCIS (Netherlands)

    Giugliano, Robert P.; Ruff, Christian T.; Braunwald, Eugene; Murphy, Sabina A.; Wiviott, Stephen D.; Halperin, Jonathan L.; Waldo, Albert L.; Ezekowitz, Michael D.; Weitz, Jeffrey I.; Špinar, Jindřich; Ruzyllo, Witold; Ruda, Mikhail; Koretsune, Yukihiro; Betcher, Joshua; Shi, Minggao; Grip, Laura T.; Patel, Shirali P.; Patel, Indravadan; Hanyok, James J.; Mercuri, Michele; Antman, Elliott M.; Braunwald, E.; Antman, E. M.; Giugliano, R. P.; Ruff, C. T.; Morin, S. E.; Hoffman, E. B.; Murphy, S. A.; Deenadayalu, N.; Grip, L.; Mercuri, M.; Lanz, H.; Patel, I.; Curt, V.; Duggal, A.; Hanyok, J.; Davé, J.; Morgan, D.; Choi, Y.; Shi, M.; Jin, J.; Xie, J.; Crerand, W.; Kappelhof, J.; Maxwell, W.; Skinner, M.; Patel, S.; Betcher, J.; Selicato, G.; Otto, C.; Reissner, C.; Smith, K.; Ostroske, J.; Ron, A.; Connolly, S.; Camm, J.; Ezekowitz, M.; Halperin, J.; Waldo, A.; Paolasso, E.; Aylward, P.; Heidbuchel, H.; Nicolau, J. C.; Goudev, A.; Roy, D.; Weitz, J.; Corbalán, R.; Yang, Y.; Botero, R.; Bergovec, M.; Ŝpinar, J.; Grande, P.; Hassager, C.; Voitk, J.; Huikuri, H.; Nieminen, M.; Blanc, J. J.; LeHeuzey, J. Y.; Mitrovic, V.; Alexopoulos, D.; Sotomora, G.; Kiss, R.; SomaRaju, B.; Lewis, B.; Merlini, P.; Metra, M.; Koretsune, Y.; Yamashita, T.; García-Castillo, A.; Oude Ophuis, T.; White, H.; Atar, D.; Horna, M.; Babilonia, N.; Ruzyllo, W.; Morais, J.; Dorobantu, M.; Ruda, M.; Ostojic, M.; Duris, T.; Dalby, A.; Chung, N.; Zamorano, J. L.; Juul-Möller, S.; Moccetti, T.; Chen, S. A.; Sritara, P.; Oto, A.; Parkhomenko, A.; Senior, R.; Verheugt, F.; Skene, A.; Anderson, J.; Bauer, K.; Easton, J. D.; Goto, S.; Wiviott, S.; Lowe, C.; Awtry, E.; Berger, C. J.; Croce, K.; Desai, A.; Gelfand, E.; Goessling, W.; Greenberger, N. J.; Ho, C.; Leeman, D. E.; Link, M. S.; Norden, A. D.; Pande, A.; Rost, N.; Ruberg, F.; Silverman, S.; Singhal, A.; Vita, J. A.; Vogelmann, O.; Gonzalez, C.; Ahuad Guerrero, R.; Rodriguez, M.; Albisu, J.; Rosales, E.; Allall, O.; Reguero, M.; Alvarez, C.; Garcia, M.; Ameriso, S.; Ameriso, P.; Amuchastegui, M.; Caceres, M.; Beloscar, J.; Petrucci, J.; Berli, M.; Budassi, N.; Valle, M.; Bustamante Labarta, G.; Saravia, M.; Caccavo, A.; Fracaro, V.; Cartasegna, L.; Novas, V.; Caruso, O.; Zarandon, R. Saa; Colombo, H.; Morandini, M.; Cuello, J.; Rosell, M.; Cuneo, C.; Bocanera, M.; D'Amico, A.; Cendali, G.; Dran, R.; Moreno, V.; Estol, C.; Davolos, M.; Facello, A.; Facello, M.; Falu, E.; Iriarte, M.; Femenia, F.; Arrieta, M.; Fuselli, J.; Zanotti, A.; Gant Lopez, J.; Meiller, F.; Garcia Duran, R.; Perlo, D.; Garrido, M.; Ceirano, C.; Giacomi, G.; Eden, M.; Giannaula, R.; Huerta, M.; Goicoechea, R.; von Wulffen, M.; Hominal, M.; Bianchini, M.; Jure, H.; Jure, D.; Kevorkian, R.; Monaco, F.; Lanternier, G.; Belcuore, M.; Liniado, G.; Iglesias, M.; Litvak, B.; Nigro, A.; Llanos, J.; Vignau, S.; Lorente, C.; Shatsky, K.; Lotti, J.; Raimondi, G.; Mackinnon, I.; Carne, M.; Manuale, O.; Calderon, M.; Marino, J.; Funes, I.; Muntaner, J.; Gandur, H.; Nul, D.; Verdini, E.; Piskorz, D.; Tommasi, A.; Povedano, G.; Casares, E.; Pozzer, D.; Fernandez, E.; Prado, A.; Venturini, C.; Ramos, H.; Navarrete, S.; Alvarez, M.; Sanchez, A.; Bowen, L.; Sanjurjo, M.; Codutti, O.; Saravia Toledo, S.; Formoso, I.; Schmidberg, J.; Goloboulicz, A.; Schygiel, P.; Buzzetti, C.; Severino, P.; Morara, P.; Sosa Liprandi, M.; Teves, M.; Vico, M.; Morell, Y.; Anderson, C.; Paraskevaidis, T.; Arstall, M.; Hoffmann, B.; Colquhoun, D.; Price-Smith, S.; Crimmins, D.; Slattery, A.; Dart, A.; Kay, S.; Davis, S.; Silver, G.; Flecknoe-Brown, S.; Roberts, J.; Gates, P.; Jones, S.; Lehman, R.; Morrison, H.; McKeirnan, M.; Li, J.; Paul, V.; Batta, C.; Purnell, P.; Perrett, L.; Szto, G.; O'Shea, V.; Capiau, L.; Banaeian, F.; de Bleecker, J.; de Koning, K.; de Tollenaere, M.; de Bruyne, L.; Desfontaines, P.; Tincani, G.; Meeusen, K.; Herzet, J.; Malmendier, D.; Mairesse, G.; Raepers, M.; Parqué, J.; Clinckemaille, N.; Scavée, C.; Huyberechts, D.; Stockman, D.; Jacobs, C.; Vandekerckhove, Y.; Derycker, K.; Vanwelden, J.; van Welden, J.; Vervoort, G.; Mestdagh, I.; Vrolix, M.; Beerts, C.; Wollaert, B.; Denie, D.; Amato Vincenzo de Paola, A.; Coutinho, E.; Andrade Lotufo, P.; de Melo, R. Ferreira; Atie, J.; Motta, C.; Augusto Alves da Costa, F.; Ferraz, R. Franchin; Bertolim Precoma, D.; Sehnem, E.; Botelho, R.; Cunha, S.; Brondani, R.; Fleck, N.; Chaves Junior, H.; Silva, J.; Costantini, C.; Barroso, D.; de Patta, M.; Pereira, V.; Duda, N.; Laimer, R.; Dutra, O.; Morgado, S.; Faustino Saporito, W.; Seroqui, M.; Ferreira, L.; Araújo, E.; Finimundi, H.; Daitz, C.; Gagliardi, R.; Pereira, G.; Gomes, M.; Gomes, A.; Guimarães, A.; Ninho, L.; Jaeger, C.; Pereira, L.; Jorge, J.; Cury, C.; Kaiser, S.; Almeida, A.; Kalil, C.; Radaelli, G.; Kunz Sebba Barroso de Souza, W.; Morales, K.; Leaes, P.; Luiz, R. Osorio; Pimenta Almeida, J.; Gozalo, A.; Reis, G.; Avellar, K.; Reis Katz Weiand, L.; Leipelt, J.; Rocha, J.; Barros, R.; Rodrigues, L.; Rocha, M. Rubia; Rodrigues, A.; Rodrigues, D.; Rossi dos Santos, F.; Pagnan, L. Goncalves; Sampaio, R.; do Val, R.; Saraiva, J.; Vicente, C.; Simoes, M.; Carraro, A.; Sobral Filho, D.; Lustosa, E.; Villas Boas, F.; Almeida, M.; Zimmermann, S.; Zimmermann, E. Bürger; Chompalova, B.; Parishev, G.; Denchev, S.; Milcheva, N.; Donova, T.; Gergova, V.; Georgiev, B.; Kostova, E.; Kinova, E.; Hergeldjieva, V.; Kamenova, P.; Manolova, A.; Vasilev, I.; Mihov, A.; Miteva, B.; Mincheva, V.; Stoyanovski, V.; Nikolov, F.; Vasilev, D.; Pencheva, G.; Kostov, K.; Petranov, S.; Milusheva, T.; Popov, A.; Staneva, A.; Momchilova-Lozeva, D.; Todorov, G.; Nyagina, M.; Tumbev, H.; Tumbeva, D.; Tzekova, M.; Kitova, M.; Manoylov, E.; Archibald, J.; Antle, S.; Bhargava, R.; Stafford, C.; Bose, S.; Hundseth, M.; Cha, J.; Otis, J.; Chehayeb, R.; Lepage, C.; Chilvers, M.; Vansickle, L.; Cleveland, D.; Valley, S.; Constance, C.; Gauthier, M.; Costi, P.; Masson, C.; Coutu, B.; Denis, I.; Du Preez, M.; Kubanska, A.; Dufresne, M.; Krider, J.; Eikelboom, J.; Zondag, M.; Fortin, C.; Viau, C.; Green, M.; Houbraken, D.; Hatheway, R.; Mabee, J.; Heath, J.; Scott, L.; Ho, K.; Ho, V.; Hoag, G.; Standring, R.; Huynh, T.; Perkins, L.; Kouz, S.; Roy, M.; Labonte, R.; Dewar, C.; Lainesse, A.; St-Germain, L.; Lam, S.; Lam, H.; Lichtenstein, T.; Roberts, P.; Luton, R.; Douglas, S.; Ma, P.; Seib, M.; MacCallum, C.; Matthews, J.; Malette, P.; Vaillancourt, T.; Maranda, C.; Studenikow, E.; Mawji, A.; Morely, A.; Morrison, D.; Roth, M.; Mucha, M.; Najarali, A.; Lamoureux, U.; Nicholson, R.; O'Hara, G.; Banville, P.; O'Mahony, W.; Bolton, R.; Parkash, R.; Carroll, L.; Pesant, Y.; Sardin, V.; Polasek, P.; Turri, L.; Qureshi, A.; Nethercott, C.; Ricci, J.; Bozek, B.; Rupka, D.; Marchand, C.; Shu, D.; Silverio, G.; St-Hilaire, R.; Morissette, A.; Sussman, J.; Kailey, P.; Syan, G.; Bobbie, C.; Talajic, M.; David, D.; Talbot, P.; Tremblay, M.; Teitelbaum, I.; Teitelbaum, J.; Velthuysen, G.; Giesbrecht, L.; Wahby, R.; Morley, A.; Wharton, S.; Caterini, T.; Woodford, T.; Balboa, W.; Matus, L. Retamal; Bugueño, C.; Mondaca, P. Mondaca; Cobos, J.; Obreque, C.; Corbalan, R.; Parada, A.; Florenzano, F.; Diaz, P. Arratia; Lopetegui, M.; Rebolledo, C.; Manriquez, L.; Silva, L. Manríquez; Martinez, D.; Llamas, R. Romero; Opazo, M.; Pérez, M. Carmona; Pincetti, C.; Carrasco, G. Torres; Potthoff, S.; Staub, J. Zapata; Campisto, Y.; Stockins, B.; Lara, C. Lara; Yovaniniz, P.; Azua, M. Grandon; Bai, F.; Xu, G. L.; Chen, J. Z.; Xie, X. D.; Chen, X. P.; Zhang, X.; Dong, Y. G.; Feng, C.; Fu, G. S.; Zhang, P.; Hong, K.; You, Z. G.; Hong, L.; Qiu, Y.; Jiang, X. J.; Qu, Z.; Li, L.; Liu, H.; Li, T. F.; Kong, Y. Q.; Li, W. M.; Liu, B.; Li, Z. Q.; Liu, Y.; Liao, D. N.; Gu, X. J.; Liu, L.; Lu, Z. H.; Ma, S. M.; Yang, Z. Y.; Wang, D. M.; Qi, S. Y.; Wang, G. P.; Shi, X. J.; Wei, M.; Huang, D.; Wu, S. L.; Li, Y. E.; Xu, J. H.; Gu, J. Y.; Xu, Y. M.; Liang, Y. Z.; Yang, K.; Li, A. Y.; Yang, Y. J.; Zheng, X.; Zheng, Y.; Gao, M.; Yin, Y. H.; Xu, Y. P.; Yu, B.; Li, L. L.; Yuan, Z. Y.; Qiang, H.; Zhang, H. Q.; Lin, Y. N.; Zhang, Z.; Kang, H.; Zhao, R. P.; Han, R. J.; Zhao, X. L.; Wang, J. Q.; Zheng, Z. Q.; Li, B. G.; Zhou, S. X.; Zhang, Y. L.; Accini, J.; Accini, M.; Cano, N.; Pineda, L. León; Delgado Restrepo, J.; Arroyave, C.; Fernández Ruiz, R.; Diaz, I. Aldana; Hernandez, H.; Delgado, P.; Jaramillo Muñoz, C.; Builes, A.; Manzur, F.; Rodriguez, E. Rivera; Moncada Corredor, M.; Giraldo, D. Lopez; Orozco Linares, L.; Fonseca, J.; Quintero, A.; Gonzales, C.; Sanchez Vallejo, G.; Mejia, I. Perdomo; Bagatin, J.; Carevic, V.; Car, S.; Jeric, M.; Ciglenecki, N.; Tusek, S.; Ferri Certic, J.; Romic, I.; Francetic, I.; Ausperger, K. Makar; Jelic, V.; Jurinjak, S. Jaksic; Knezevic, A.; Buksa, B.; Samardzic, P.; Lukenda, K. Cvitkusic; Steiner, R.; Kirner, D.; Sutalo, K.; Bakliza, Z.; Vrazic, H.; Lucijanic, T.; Bar, M.; Brodova, P.; Berka, L.; Kunkelova, V.; Brtko, M.; Burianova, H.; Cermak, O.; Elbl, L.; Ferkl, R.; Florian, J.; Francek, L.; Golan, L.; Gregor, P.; Honkova, M.; Hubac, J.; Jandik, J.; Jarkovsky, P.; Jelinek, Z.; Jerabek, O.; Jirmar, R.; Kobza, R.; Kochrt, M.; Kostkova, G.; Kosek, Z.; Kovar, P.; Kuchar, R.; Kvasnicka, J.; Ludka, O.; Machova, V.; Krocova, E.; Melichar, M.; Nechanicky, R.; Olsr, J.; Peterka, K.; Petrova, I.; Havlova, I.; Pisova, J.; Podrazil, P.; Jirsova, E.; Reichert, P.; Slaby, J.; Spacek, R.; Spinar, J.; Labrova, R.; Vodnansky, P.; Samkova, D.; Zidkova, E.; Dodt, K.; Christensen, H.; Christensen, L.; Loof, A.; Ibsen, H.; Madsen, H.; Iversen, H.; Veng-Olsen, T.; Nielsen, H.; Olsen, R.; Overgaard, K.; Petrovic, V.; Raymond, I.; Raae, D.; Sand, N.; Svenningsen, A.; Torp-Pedersen, C.; Jakobsen, U.; Wiggers, H.; Serup-Hansen, K.; Kaik, J.; Stern, A.; Kolk, R.; Laane, E.; Rivis, L.; Paumets, M.; Laheäär, M.; Rosenthal, A.; Rajasalu, R.; Vahula, V.; Ratnik, E.; Kaarleenkaski, S.; Hussi, E.; Valpas, S.; Jäkälä, P.; Lappalainen, T.; Mäenpää, A.; Viitaniemi, J.; Nyman, K.; Sankari, T.; Rasi, H.; Salminen, O.; Virtanen, V.; Nappila, H.; Le Heuzey, J.; Agraou, B.; El Jarroudi, F.; Amarenco, P.; Boursin, P.; Babuty, D.; Boyer, M.; Belhassane, A.; Berbari, H.; Blanc, J.; Dias, P.; Coisne, D.; Berger, N.; Decoulx, E.; El Jarroudi, M.; Dinanian, S.; Arfaoui, M.; Hermida, J.; Deruche, E.; Kacet, S.; Corbut, S.; Poulard, J.; Leparree, S.; Roudaut, R.; Duprat, C.; Al-Zoebi, A.; Wurow, A.; Bernhardt, P.; Dichristin, U.; Berrouschot, J.; Vierbeck, S.; Beyer-Westendorf, J.; Sehr, B.; Bouzo, M.; Schnelzer, P.; Braun, R.; Ladenburger, K.; Buhr, M.; Weihrauch, D.; Contzen, C.; Kara, M.; Daut, W.; Ayasse, D.; Degtyareva, E.; Kranz, P.; Drescher, T.; Herfurth, B.; Faghih, M.; Forck-Boedeker, K.; Schneider, K.; Fuchs, R.; Manuela, W.; Grigat, C.; Otto, A.; Hartmann, A.; Peitz, M.; Heuer, H.; Dieckheuer, U.; Hoffmann, U.; Dorn, S.; Hoffmann, S.; Schuppe, M.; Horacek, T.; Fink, P.; Junggeburth, J.; Schmid, S.; Jungmair, W.; Schoen, B.; Kleinecke-Pohl, U.; Meusel, P.; Koenig, H.; Bauch, F.; Lohrbaecher-Kozak, I.; Grosse, B.; Lueders, S.; Venneklaas, U.; Luttermann, M.; Wulf, M.; Maus, O.; Hoefer, K.; Meissner, G.; Braemer, U.; Meyer-Pannwitt, U.; Frahm, E.; Vogt, S.; Muegge, A.; Barbera, S.; Mueller-Glamann, M.; Raddatz, K.; Piechatzek, R.; Lewinsky, D.; Pohl, W.; Proskynitopoulos, N.; Kuhlmann, M.; Rack, K.; Pilipenko, H.; Rinke, A.; Kühlenborg, A.; Schaefer, A.; Szymanowski, N.; Schellong, S.; Frommhold, R.; Schenkenberger, I.; Finsterbusch, T.; Dreykluft, K.; Schiewe, C.; Schmidt, A.; Schmidt, M.; Schreckenberg, A.; Hellmers, J.; Seibert, H.; Gold, G.; Sohn, H.; Baylacher, M.; Spitzer, S.; Bonin, K.; Stoehring, R.; Taggeselle, J.; Zarpentin, C.; Veltkamp, R.; Ludwig, I.; Voehringer, N. N.; Buchholz, M.; Weyland, K.; Winkelmann, B.; Buelow-Johansen, B.; Wolde, C.; Winter, K.; Mavronasiou, E.; Bourlios, P.; Tziortziotis, A.; Karamitsos, C.; Exarchou, E.; Kifnidis, K.; Daskalaki, A.; Moschos, N.; Dimitra, K.; Olympios, C.; Kartsagkoulis, E.; Pyrgakis, V.; Korantanis, K.; Ayau Milla, O.; Ramirez, V. de Leon; Guzman Melgar, I.; Jimenez, T.; Ovando Lavagnino, A.; Guevara, S.; Rodas Estrada, M.; Sanchez, M.; Pozuelos, J. Mayen; Sanchez Samayoa, C.; Guerra, L.; Velasquez Camas, L.; Almaraz, S. Padilla; Dioszeghy, P.; Muskoczki, E.; Edes, I.; Szatmari, J.; Fiok, J.; Varga, A.; Kanakaridisz, N.; Kosztyu, M.; Kis, E.; Feil, J. Felfoldine; Jakal, A.; Koczka, M.; Kovacs, I.; Baranyai, M.; Kovacs, Z.; Lupkovics, G.; Karakai, H. Horvathne; Matoltsy, A.; Kiss, T.; Medvegy, M.; Kiss, K.; Merkely, B.; Kolumban, E.; Nagy, A.; Palinkas, A.; Toth, S. Rostasne; Sayour, A.; Bognar, A.; Simor, T.; Ruzsa, D.; Sipos, T.; Szakal, I.; Tomcsanyi, J.; Marosi, A.; Vertes, A.; Kincses, M.; Malhan, S.; Abdullakutty, J.; Agarwal, D.; Ranka, R.; Arneja, J.; Memon, A.; Arora, V.; Shree, R.; Avvaru, G.; Shaikh, A.; Babu, P.; Rao, B.; Babu, R.; Reddy, J.; Banker, D.; Sheth, T.; Benjarge, P.; Surushe, S.; Bharani, A.; Solanki, R.; Bhargava, V.; Rathi, A.; Biniwale, A.; Bhuti, M.; Calambur, N.; Karnwal, N.; Chopda, M.; Mali, N.; Goyal, N.; Saini, A.; Gupta, J.; Singh, P.; Hadan, S.; Savanth, P.; Hardas, S.; Thakor, G.; Hiremath, J.; Ghume, A.; Jain, R.; Pahuja, M.; Joseph, S.; Oommen, D.; Joseph, J.; Thomas, R.; Joshi, H.; Iby, N. N.; Kale, V.; Raut, N.; Kandekar, B.; Kandekar, S.; Kishore, R.; Krishnan, H.; Kotiwale, V.; Kulkarni, R.; Deokar, M.; Kulkarni, G.; Lawande, A.; Kumar, P.; Karpuram, M.; Kumar, A.; Francis, J.; Kumbla, M.; Anthony, A.; Lavhe, P.; Kale, M.; Mardikar, H.; Bhaskarwar, P.; Mathur, A.; Sharma, P.; Menon, J.; Francis, V.; Namjoshi, D.; Shelke, S.; Narendra, J.; Natarajan, S.; Oomaan, A.; Gurusamy, P.; Angel, J.; Purayil, M. Padinhare; Shams, S.; Pandurangi, U.; Sababathi, R.; Parekh, P.; Jasani, B.; Patki, N.; Babbar, A.; Pinto, B.; Kharalkar, H.; Premchand, R.; Jambula, H.; Rao, M.; Vuriya, A.; Ravi Shankar, A.; Reddy, R.; Bekal, S.; Barai, A.; Saha, D.; Gadepalli, R.; Sant, H.; Jadhav, D.; Sarna, M.; Arora, T.; Sawhney, J.; Singh, R.; Sethi, K.; Bansal, N.; Sethia, A.; Sethia, S.; Shetty, G.; Sudheer, R.; Singh, G.; Gupta, R.; Srinivas, A.; Thankaraj, L.; Varma, S.; Kaur, A.; Vinod, M. Vijan; Thakur, B.; Zanwar, I.; Dharmarao, A.; Atar, S.; Lasri, E.; Dicker, D.; Marcoviciu, D.; Elias, M.; Ron, G. Avraham; Francis, A.; Ghantous, R.; Goldhaber, A.; Goldhaber, M.; Gottlieb, S.; Rouwaida, S.; Grossman, E.; Dagan, T.; Hasin, Y.; Roshrosh, M.; Hayek, T.; Majdoub, A.; Klainman, E.; Genin, I.; Lahav, M.; Gilat, T.; Ben Ari, M.; Lishner, M.; Karny, M.; Ouzan, E.; Givoni, H.; Rozenman, Y.; Logvinenko, S.; Schiff, E.; Sterlin, J.; Shochat, M.; Aloni, I.; Swissa, M.; Belatsky, V.; Tsalihin, D.; Kisos, D.; Zeltser, D.; Platner, N.; Berni, A.; Giovannelli, F.; Boriani, G.; Cervi, E.; Comi, G.; Peruzzotti, L.; Cuccia, C.; Forgione, C.; de Caterina, R.; de Pace, D.; de Servi, S.; Mariani, M.; Di Lenarda, A.; Mazzone, C.; Di Pasquale, G.; Di Niro, M.; Fattore, L.; Bosco, B.; Grassia, V.; Murena, E.; Laffi, N. 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Cedano; Cardona Muñoz, E.; Hernandez, S.; Carrillo, J.; Delgadillo, T.; Cásares Ramirez, M.; Valles, J. Franco; Garcia, N.; Colin, M. Alcantara; Garcia-Castillo, A.; Jaramillo, A.; Leiva-Pons, J.; de la Mora, S.; Llamas Esperón, G.; Grajales, A.; Mendez-Machado, G.; Avila, H.; Ruiz, L. Nevárez; Magallanes, G.; Sánchez Díaz, C.; Ortiz, A.; Sánchez, R. Velasco; Velazquez, E. Moran; Alhakim, M.; van Welsen, I.; Bruning, T.; Jones, A.; Buiks, C.; de Groot, J. [=Joris R.; Radder, I.; de Vos, R.; Hazeleger, R.; Daniels, R.; Kietselaer, B.; Muijs, L.; Mannaerts, H.; Kooiman, E.; Mevissen, H.; van der Heijden, D.; Hofmeyer, H.; Anscombe, R.; O'Meeghan, T.; Kjentjes, M.; Benatar, J.; Borthwick, L.; Doughty, R.; Copley, M.; Fisher, R.; Monkley, R.; Green, B.; Scott, D.; Hamer, A.; Tomlinson, J.; Hart, H.; Turner, A.; Cammell, R.; Troughton, R.; Skelton, L.; Young, C.; Kennett, K.; Claussen, H.; Hofsøy, K.; Melbue, R.; Sandvik, J.; Thunhaug, H.; Tveit, A.; Enger, S.; Bustamante, G.; Guillen, M. Tejada; Cabrera, J.; Mendoza, R. Esteves; Chavez, C.; Luna, C.; Lema, J.; Carrion, A.; Llerena, N.; Bedregal, S. Araoz; Medina Palomino, F.; Rodriguez, J.; Minchola, J.; Bautista, C.; Negron Miguel, S.; Armas, B. Honores; Rodriguez, A.; Romero, N.; Torres, P.; Rodriguez, K. Fernandez; Yanac Chavez, P.; Delgado, S.; Sambaz, C. M.; Barcinas, R.; Zapanta, M.; Coching, R.; Vallenas, M.; Matiga, G.; Enad, C.; Rogelio, G.; Joaquin, F.; Roxas, A.; Gilo, L.; To, R.; Aquino, M.; Villamor, L.; Nario, K.; Adamus, J.; Korzeniowska-Adamus, J.; Baszak, J.; Bronisz, M.; Cieslak, B.; Busz-Papiez, B.; Krzystolik, A.; Cymerman, K.; Dabrowska, M.; Ptak, A.; Derlaga, B.; Laskowska-Derlaga, E.; Domanska, E.; Guziewicz, M.; Gieroba, A.; Zajac, E.; Gniot, J.; Mroczkowski, P.; Januszewicz, A.; Makowiecka-Ciesla, M.; Jazwinska-Tarnawska, E.; Ciezak, P.; Jurowiecki, J.; Kaczmarek, B.; Pacholska, A.; Kaminski, L.; Kania, G.; Tymendorf, K.; Karczmarczyk, A.; Kaliszczak, R.; Konieczny, M.; Benicka, E.; Korzeniak, R.; Borowski, W.; Krzyzanowski, W.; Muzyk-Osikowicz, M.; Kus, W.; Lesnik, J.; Wierzykowski, T.; Lewczuk, J.; Stopyra-Poczatek, M.; Lubinski, A.; Szymanska, K.; Lysek, R.; Jaguszewska, G.; Matyszczak-Toniak, L.; Sznajder, R.; Wnetrzak-Michalska, R.; Kosmaczewska, A.; Mazur, S.; Chmielowski, A.; Miekus, P.; Kosmalska, K.; Mosiewicz, J.; Myslinski, W.; Napora, P.; Biniek, D.; Nessler, J.; Nessler, B.; Niezgoda, K.; Nej, A.; Nowak, J.; Olszewski, M.; Podjacka, D.; Janczewska, D.; Pogorzelska, H.; Polaszewska-Pulkownik, V.; Bojanowska, E.; Raczak, G.; Zienciuk-Krajka, A.; Rewinska, H.; Rozmyslowicz-Szerminska, W.; Ronkowski, R.; Norwa-Otto, B.; Sendrowski, D.; Spyra, J.; Szolkiewicz, M.; Malanska, A.; Turbak, R.; Wrobel, W.; Muzalewski, P.; Wysokinski, A.; Kudlicki, J.; Zarebinski, M.; Krauze, R.; Zielinski, M.; Nawrot, M.; Matias, F.; Correia, J.; Gil, V.; Lopes, S.; Madeira, J.; Maymone, D.; Martins, D.; Neves, E.; Monteiro, P.; Oliveira, D.; Marques, A. Leitao; Castro, C.; Salgado, A.; Gonçalves, A.; Sao Marcos, H.; Santos, O.; Nunes, L. 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Gordon, L.; Bartkowiak, A.; Benton, J.; Beasley, R.; Hoffman, T.; Bedoya, R.; Luis-Valdes, M.; Bedwell, N.; Craig, M.; Beinart, S.; Swaim, D.; Bensimhon, D.; Garman, V.; Berk, M.; Ibarra, M.; Bernard, J.; Eldred, R.; Bilal, B.; Preston, S.; Bilazarian, S.; Langone, L.; Bingham, S.; Antonino, M.; Block, T.; Talbot-Lawson, C.; Blonder, R.; Ensminger, E.; Bloomberg, R.; Bloomberg, K.; Blue, B.; Vernon, M.; Borsheim, M.; Hickenbotham, D.; Bouchard, A.; Wade, W.; Bowden, W.; Ziegler, K.; Bradley, A.; Terry, P.; Brilakis, E.; Frey, W.; Brown, H.; Triano, A.; Bybee, K.; Al-Maliky, T.; Cader, C.; Morton, S.; Canaday, D.; Canosa, R.; Hartranft, E.; Caplan, J.; Jameson, L.; Carr, K.; Phan, D.; Chang, M.; Hatfield, G.; Charlat, M.; Tamayo, M.; Chaturvedi, S.; Sawaya, K.; Ciaramita, J.; Bagby, J.; Clapp, T.; Clay, A.; McClelland, M.; Dutka, C.; Cohen, R.; Bossaers, J.; Colan, D.; Salpas, S.; Cole, J.; Fisher, M.; Concha, M.; Martinez, E.; Corbett, B.; Svadbik, L.; Cossu, S.; Mullinax, K.; Cottiero, R.; Masson, E.; Cowan, L.; Nelson, L.; Curtis, B.; Sarpola, N.; Dang, N.; Morgan, T.; Daniels, S.; Leka, G.; Datta, S.; Wulf, A.; Dave, K.; Dave, B.; Davuluri, A.; Ebreo, N.; de Lemos, J.; Debes, C.; Dean, J.; Warmack, D.; Degarmo, R.; Carey, J.; Steward, A.; Desire, A.; Waters, L.; Devenport, S.; Briscoe, C.; Dhar, S.; Ucik, S.; DiGiovanna, M.; Tisdale, L.; Donovan, D.; Rodriguez, L.; Dotani, I.; Olson, A.; Drozdiak, R.; Habibi, S.; D'Souza, A.; Cullen, T.; Eade, J.; Dunn, K.; Eldadah, Z.; Quick, R.; Ellis, J.; Cristaldi, J.; Erenrich, N.; Johnson, C.; O'Brien, J.; Ettinger, N.; Shipp, A.; Everhart, B.; DeSalle, D.; Fahmy, R.; Watkins, D.; Feld, L.; Tameron, A.; Feldman, J.; Tang, N.; Felten, W.; Prior, J.; Fialkow, J.; Calvo, M.; Finkel, M.; Shriver, D.; Finkelstein, S.; Fischell, T.; Drew, B.; Fishbein, G.; Donahue, S.; Flores, E.; Slayton, C.; Forman, S.; Solis, A.; Frais, M.; Thrope, C.; Franco, M.; Gentry, P.; French, W.; Morales, C.; Friedlander, I.; Gaffney, M.; Jones, J.; Garb, J.; 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Stagi; Landau, C.; Ferguson, D.; Lang, J.; Simmons, T.; Langevin, E.; Faucett, S.; Ledbetter, L.; Royse, H.; Lentz, M.; Smith, D.; Lesser, M.; Hartley, L.; Lewis, D.; Bonds, C.; Lillestol, M.; Miller, D.; Ling, L.; Murphy, R.; Littlefield, R.; Wofford, E.; Lomnitz, D.; Lone, B.; Davids, M.; Looby, R.; Ault, S.; Lui, H.; Wright, H.; Lurie, M.; Edelstein, J.; Macomber, J.; Bush, D.; Magee, A.; Doctor, A.; Mainigi, S.; Lisiecki, B.; Makam, S.; Casas, R.; Mandviwala, M.; Marar, I.; Rabadi-Marar, D.; Marenberg, M.; Bedenko, E.; Massin, E.; Hicks, T.; McCartney, M.; Stubbs, L.; McGarvey, J.; Schwarz, L.; McGuire, K.; McKenzie, M.; Rodkey, K.; McKnight, T.; Paul, J.; McLaurin, B.; Lack, A.; Mega, J.; Marti, J.; Meholick, A.; Skinner, J.; Mehrle, A.; Wall, J.; Mendelson, R.; Cervellione, K.; Mercado, A.; Cajulis, C.; Michlin, B.; Romero-Colon, J.; Milas, J.; Sanders, D.; Miller, R.; Sanchez, S.; Miller, S.; Gryczan, J.; Mody, F.; Strugatsky, S.; Moran, J.; Garner, S.; Morledge, J.; Bowman, B.; Mouhaffel, A.; Parrott, N.; Mounsey, P.; Schuler, C.; Mowdy, M.; Todd, S.; Mullen, P.; Raziano, S.; Murphy, A.; Oehmann, V.; Nadar, V.; Parker, A.; Naidu, J.; West, M.; Nallasivan, M.; Goza, J.; Nguyen, T.; Nomanee, S.; Nielsen, R.; Wilmot, M.; Oberoi, M.; Thakkar, N.; Oppenheimer, K.; McCormick, J.; Orchard, R.; Garcia, L.; Osborne, J.; Gonzalez, M.; Oza, S.; Joseph, L.; Patnam, S.; Dennison, K.; Pavon, H.; Gorry, N.; Pearlstein, R.; Montayne, S.; Pentz, W.; Duncan, D.; Peters, P.; Chacon, L.; Petruzziello, F.; Morlando, F.; Pettis, K.; Brown, F.; Pezzella, S.; Kirk, D.; Poulathas, A.; Cush, S.; Pratt, R.; Neeper, L.; Pribble, A.; Lowe, K.; Pudi, K.; Sham, L.; Pugeda, J.; Ebert, J.; Quadrel, M.; Rafla, E.; Quinlan, E.; Reed, C.; Quinn, J.; Hemmen, C.; Rama, P.; Domingo, D.; Redondo, V.; Wroblewski, J.; Renzi, M.; Stanley, E.; Richwine, R.; Pazier, P.; Riofrio, K.; Braun, D.; Robinson, J.; Cherrico, M.; Roehll, W.; Hollihan, P.; Rosado, N. N.; Barnhorst, M.; Rosado, J.; Bamhorst, M.; Rosen, R.; Martin, C.; Ross, S.; Freeman, R.; Ruoff, G.; Nelson, T.; Sacco, J.; Ball, E.; Samal, A.; Schomburg, J.; Sandberg, J.; Lafave, J.; Savin, V.; Clifton, R.; Schaefer, S.; Fekete, A.; Schneider, R.; Schneider, W.; Schulman, D.; Mercer, S.; Seals, A.; Ullig, T.; Holt, A.; Seide, H.; Mather, N.; Shah, G.; Witt, P.; Shalaby, A.; Seese, M.; Shanes, J.; Fleets, J.; Shaoulian, E.; Hren, A.; Sheikh, K.; Hengerer, T.; Shih, H.; Browning, J.; Shoukfeh, M.; Stephenson, L.; Siler, T.; Champagne, M.; Simpson, P.; Meyer, R.; Singh, N.; Turner, K.; Singh, V.; Nelson, M.; Skierka, R.; Hughes, B.; Keene, R.; Smith, R.; Hodnett, P.; Spangenthal, S.; Thomason, L.; Sperling, M.; Vasquez, E.; Spivack, E.; McCartney, P.; Staniloae, C.; Liu, M.; Steljes, A.; Cox, C.; Struble, R.; Vittitow, T.; Suresh, D.; Frost, J.; Swerchowsky, V.; Freemyer, D.; Szulawski, I.; Herwehe, S.; Tahirkheli, N.; Springer, K.; Takata, T.; Bruton, T.; Talano, J.; Leo, L.; Tami, L.; Corchado, D.; Tatarko, M.; Swauger, M.; Tawney, K.; Dastoli, K.; Teague, S.; Young, K.; tee, H.; Mitchell, T.; Teixeira, J.; Southam, D.; Torres, M.; Tucker, P.; Salas, L.; Updegrove, J.; Hanna, K.; Val-Mejias, J.; Harrelson, K. Gonzalez; Vemireddy, D.; Cardoza, T.; Verma, S.; Parsons, T.; Vicari, R.; Warren, K.; Vijay, N.; Washam, M.; Vossler, M.; Kilcup, S.; Walsh, R.; Renaud, K.; Ward, S.; Locklear, T.; Waxman, F.; Sanchez, G.; Weiss, R.; St Laurent, B.; Westcott, J.; Williams, D.; Gibson, C.; Williams, R.; Dowling, C.; Willis, J.; VonGerichten, S.; Wood, K.; Capasso-Gulve, E.; Worley, S.; Pointer, S.; Yarows, S.; Sheehan, T.; Yasin, M.; Yi, J.; Dongas, B.; Yousuf, K.; Zakhary, B.; Curtis, S.; Zeig, S.; Mason, T.; Zellner, C.; Harden, M.; Roper, E.; Waseem, M.; Grammer, M.

    2013-01-01

    BackgroundEdoxaban is a direct oral factor Xa inhibitor with proven antithrombotic effects. The long-term efficacy and safety of edoxaban as compared with warfarin in patients with atrial fibrillation is not known. MethodsWe conducted a randomized, double-blind, double-dummy trial comparing two

  3. Evalutating Inward Rectifier Current Inhibiton for Treatment of Atrial Fibrillation

    NARCIS (Netherlands)

    Ji, Yuan

    2017-01-01

    Atrial Fibrillation (AF) is one of the most common forms of cardiac arrhythmia and affects a large percentage of the human population, especially in the elderly. Currently, more than 6 million Europeans suffer from AF, and due to ageing this number will at least double in the next 50 years.

  4. Atrial fibrillation: An analysis of etiology and management pattern in ...

    African Journals Online (AJOL)

    Hypertensive heart disease was the diagnosis in forty patients [58.82%], dilated cardiomyopathy in thirteen [19.2%], rheumatic heart disease in ten [14.71%], thyrotoxicosis in three [4.41%], one each due to endomyocardial fibrosis [EMF] and Cor pulmonale. Ten patients (14.71%) had valvular atrial fibrillation (AF) while most ...

  5. Occlusion of left atrial appendage in patients with atrial fibrillation

    Directory of Open Access Journals (Sweden)

    О. Н. Ганеева

    2015-10-01

    Full Text Available The article reviews a new method of prophylaxis of thromboembolitic complications, specifically occlusion of left atrial appendage, in patients with atrial fibrillation. Indications and contraindications for the procedure, as well as a step-by-step process of the intervention itself are described. Special emphasis is placed on the up-to-date evidence and the review of clinical trials.

  6. Overweight and obesity in patients with atrial fibrillation

    DEFF Research Database (Denmark)

    Boriani, Giuseppe; Laroche, Cécile; Diemberger, Igor

    2018-01-01

    BACKGROUND: The impact of overweight and obesity on outcomes in "real world" patients with atrial fibrillation (AF) is not fully defined. Second, sex differences in AF outcomes may also exist. METHODS AND RESULTS: The aim was to investigate outcomes at 1-year follow-up for AF patients enrolled in...

  7. Ischaemia-induced cellular electrical uncoupling and ventricular fibrillation

    NARCIS (Netherlands)

    de Groot, J. R.

    2002-01-01

    Sudden death resulting from ventricular fibrillation (VF) during acute myocardial ischaemia forms an important contribution to mortality associated with infarction. Its temporal distribution is not known, but 30% of mortality occurs within the first 60 minutes. Two distinct phases of arrhythmias

  8. Ebstein's anomaly as a cause of paroxysmal atrial fibrillation

    Directory of Open Access Journals (Sweden)

    Damjanović Miodrag R.

    2008-01-01

    Full Text Available Background. Ebstein's anomaly is characterized by a displacement of the tricuspid valve toward apex, because of anomalous attachment of the tricuspid leaflets. There are type B of Wolff-Parkinson-White (WPW syndrome and paroxysmal arrhythmias in more than a half of all patients. Case report. We presented a female, 32-year old, with frequent paroxysms of atrial fibrillation. After conversion of rhythm an ECG showed WPW syndrome. Echocardiographic examination discovered normal size of the left cardiac chambers with paradoxical ventricular septal motion. The right ventricle was very small because of its atrialization. The origin of the tricuspid valve was 20 mm closer to apex of the right ventricle than the origin of the mitral valve. Electrophysiological examination showed a posterolateral right accesorial pathway. Atrial fibrillation was induced very easily in electrophysiological laboratory and a successful ablation of accessorial pathway was made. There were no WPW syndrome and paroxysms of atrial fibrillation after that. Conclusion. Ebstein's anomaly is one of the reasons of paroxysmal atrial fibrillation, especially in young persons with WPW syndrome.

  9. Paroxysmal atrial fibrillation, quality of life and neuroticism

    NARCIS (Netherlands)

    van den Berg, Maarten; Ranchor, A.V.; van Sonderen, F.L.; van Gelder, I.C.; van Veldhuisen, D.J.

    Background: Paroxysmal atrial fibrillation (AF) is associated with significant impairment of quality of life (QoL), which is to a large extent independent of objective measures of disease severity. We sought to investigate the potential role of neuroticism in the impairment of QoL in patients with

  10. Outcomes Associated With Familial Versus Nonfamilial Atrial Fibrillation

    DEFF Research Database (Denmark)

    Gundlund, Anna; Olesen, Jonas Bjerring; Staerk, Laila

    2016-01-01

    BACKGROUND: We examined all-cause mortality and long-term thromboembolic risk (ischemic stroke, transient ischemic attack, systemic thromboembolism) in patients with and without familial atrial fibrillation (AF). METHODS AND RESULTS: Using Danish nationwide registry data, we identified all patients...

  11. Heterogeneous amylin fibril growth mechanisms imaged by total internal reflection fluorescence microscopy.

    Science.gov (United States)

    Patil, Sharadrao M; Mehta, Andrew; Jha, Suman; Alexandrescu, Andrei T

    2011-04-12

    Total internal reflection fluorescence microscopy has been used to visualize the fibrillization of amylin, a hormone which in aggregated forms plays a role in type 2 diabetes pathology. Data were obtained at acidic pH where fibrillization is hindered by the charging of histidine 18 and at slightly basic pH where the loss of charge on the histidine promotes aggregation. The experiments show three types of aggregate growth processes. In the earliest steps globular seeds are formed with some expanding radially during the course of the reaction. The dimensions of the globular seeds as well as their staining with the amyloid-specific dye thioflavin T indicate that they are plaques of short fibrils. The next species observed are fibrils that invariably grow from large globular seeds or smaller punctate granules. Fibril elongation appears to be unidirectional, although in some cases multiple fibrils radiate from a single seed or granule. After fibrils are formed, some show an increase in fluorescence intensity that we attribute to the growth of new fibrils alongside those previously formed. All three aggregation processes are suggestive of secondary (heterogeneous) nucleation mechanisms in which nucleation occurs on preformed fibrils. Consistently, electron micrographs show changes in fibril morphology well after fibrils are first formed, and the growth processes observed by fluorescence microscopy occur after the corresponding solution reactions have reached an initial apparent plateau. Taken together, the results highlight the importance of secondary nucleation in the fibrillization of amylin, as this could provide a pathway to continue fibril growth once an initial population of fibrils is established.

  12. Aortic stiffness in lone atrial fibrillation: a novel risk factor for arrhythmia recurrence.

    Directory of Open Access Journals (Sweden)

    Dennis H Lau

    Full Text Available BACKGROUND: Recent community-based research has linked aortic stiffness to the development of atrial fibrillation. We posit that aortic stiffness contributes to adverse atrial remodeling leading to the persistence of atrial fibrillation following catheter ablation in lone atrial fibrillation patients, despite the absence of apparent structural heart disease. Here, we aim to evaluate aortic stiffness in lone atrial fibrillation patients and determine its association with arrhythmia recurrence following radio-frequency catheter ablation. METHODS: We studied 68 consecutive lone atrial fibrillation patients who underwent catheter ablation procedure for atrial fibrillation and 50 healthy age- and sex-matched community controls. We performed radial artery applanation tonometry to obtain central measures of aortic stiffness: pulse pressure, augmentation pressure and augmentation index. Following ablation, arrhythmia recurrence was monitored at months 3, 6, 9, 12 and 6 monthly thereafter. RESULTS: Compared to healthy controls, lone atrial fibrillation patients had significantly elevated peripheral pulse pressure, central pulse pressure, augmentation pressure and larger left atrial dimensions (all P<0.05. During a mean follow-up of 2.9±1.4 years, 38 of the 68 lone atrial fibrillation patients had atrial fibrillation recurrence after initial catheter ablation procedure. Neither blood pressure nor aortic stiffness indices differed between patients with and without atrial fibrillation recurrence. However, patients with highest levels (≥75(th percentile of peripheral pulse pressure, central pulse pressure and augmentation pressure had higher atrial fibrillation recurrence rates (all P<0.05. Only central aortic stiffness indices were associated with lower survival free from atrial fibrillation using Kaplan-Meier analysis. CONCLUSION: Aortic stiffness is an important risk factor in patients with lone atrial fibrillation and contributes to higher atrial

  13. Managing transmission curtailment risk in wholesale power markets

    Energy Technology Data Exchange (ETDEWEB)

    Morey, Mathew J.; Kirsch, Laurence D.

    2009-11-15

    Risk resulting from transmission loading relief calls made by transmission system operators can be managed with information estimated by a statistical model capable of predicting one day in advance the probability that a particular wholesale power transaction might be curtailed. The model predicts this probability with a reasonable degree of accuracy using information on variables that can be obtained publicly. (author)

  14. Open Access Transmission Tariff: Effective December 18, 1998 (Revised June 16, 1999).

    Energy Technology Data Exchange (ETDEWEB)

    United States. Bonneville Power Administration.

    1999-06-16

    Bonneville will provide Network Integration Transmission Service pursuant to the terms and conditions contained in this Tariff and Service Agreement. The service that Bonneville will provide under this Tariff allows a Transmission Customer to integrate, economically dispatch and regulate its current and planned Network Resources to serve its Network Load. Network Integration Transmission Service also may be used by the Transmission Customer to deliver nonfirm energy purchases to its Network Load without additional charge. To the extent that the transmission path for moving power from a Network Resource to a Network Load includes the Eastern and Southern Interties, the terms and conditions for service over such intertie facilities are provided under Part 2 of this Tariff. Also, transmission service for third-party sales which are not designated as Network Load will be provided under Bonneville's Point-to-Point Transmission Service (Part 2 of this Tariff).

  15. Albumin fibrillization induces apoptosis via integrin/FAK/Akt pathway

    Directory of Open Access Journals (Sweden)

    Liang Chi-Ming

    2009-01-01

    Full Text Available Abstract Background Numerous proteins can be converted to amyloid-like fibrils to increase cytotoxicity and induce apoptosis, but the methods generally require a high concentration of protein, vigorous shaking, or fibril seed. As well, the detailed mechanism of the cytotoxic effects is not well characterized. In this study, we have developed a novel process to convert native proteins into the fibrillar form. We used globular bovine serum albumin (BSA as a model protein to verify the properties of the fibrillar protein, investigated its cellular effects and studied the signaling cascade induced by the fibrillar protein. Results We induced BSA, a non-cytotoxic globular protein, to become fibril by a novel process involving Superdex-200 column chromatography in the presence of anionic or zwittergenic detergent(s. The column pore size was more important than column matrix composite in fibril formation. The fibrillar BSA induced apoptosis in BHK-21 cell as well as breast cancer cell line T47D. Pre-treating cells with anti-integrin antibodies blocked the apoptotic effect. Fibrillar BSA, but not globular BSA, bound to integrin, dephosphorylated focal adhesion kinase (FAK, Akt and glycogen synthase kinase-3β (GSK-3β. Conclusion We report on a novel process for converting globular proteins into fibrillar form to cause apoptosis by modulating the integrin/FAK/Akt/GSK-3β/caspase-3 signaling pathway. Our findings may be useful for understanding the pathogenesis of amyloid-like fibrils and applicable for the development of better therapeutic agents that target the underlying mechanism(s of the etiologic agents.

  16. Personalized management of atrial fibrillation : Proceedings from the fourth Atrial Fibrillation competence NETwork/European Heart Rhythm Association consensus conference

    NARCIS (Netherlands)

    Kirchhof, Paulus; Breithardt, Guenter; Aliot, Etienne; Al Khatib, Sana; Apostolakis, Stavros; Auricchio, Angelo; Bailleul, Christophe; Bax, Jeroen; Benninger, Gerlinde; Blomstrom-Lundqvist, Carina; Boersma, Lucas; Boriani, Giuseppe; Brandes, Axel; Brown, Helen; Brueckmann, Martina; Calkins, Hugh; Casadei, Barbara; Clemens, Andreas; Crijns, Harry; Derwand, Roland; Dobrev, Dobromir; Ezekowitz, Michael; Fetsch, Thomas; Gerth, Andrea; Gillis, Anne; Gulizia, Michele; Hack, Guido; Haegeli, Laurent; Hatem, Stephane; Haeusler, Karl Georg; Heidbuechel, Hein; Hernandez-Brichis, Jessica; Jais, Pierre; Kappenberger, Lukas; Kautzner, Joseph; Kim, Steven; Kuck, Karl-Heinz; Lane, Deirdre; Leute, Angelika; Lewalter, Thorsten; Meyer, Ralf; Mont, Lluis; Moses, Gregory; Mueller, Markus; Muenzel, Felix; Naebauer, Michael; Nielsen, Jens Cosedis; Oeff, Michael; Oto, Ali; Pieske, Burkert; Pisters, Ron; Potpara, Tatjana; Rasmussen, Lars; Ravens, Ursula; Reiffel, James; Richard-Lordereau, Isabelle; Schaefer, Herbert; Schotten, Ulrich; Stegink, Wim; Stein, Kenneth; Steinbeck, Gerhard; Szumowski, Lukasz; Tavazzi, Luigi; Themistoclakis, Sakis; Thomitzek, Karen; Van Gelder, Isabelle C.; von Stritzky, Berndt; Vincent, Alphons; Werring, David; Willems, Stephan; Lip, Gregory Y. H.; Camm, A. John

    2013-01-01

    The management of atrial fibrillation (AF) has seen marked changes in past years, with the introduction of new oral anticoagulants, new antiarrhythmic drugs, and the emergence of catheter ablation as a common intervention for rhythm control. Furthermore, new technologies enhance our ability to

  17. Early recurrences of atrial fibrillation after electrical cardioversion : A result of fibrillation-induced electrical remodeling of the atria?

    NARCIS (Netherlands)

    Tieleman, RG; Van Gelder, IC; Crijns, HJGM; De Kam, PJ; Van den Berg, MP; Haaksma, J; Van der Woude, HJ; Allessie, MA

    Objectives, We sought to investigate whether, in humans, the timing and incidence of a relapse of atrial fibrillation (AF) during the first month after cardioversion indicates the presence of electrical remodeling and whether this could be influenced by prevention of intracellular calcium overload

  18. Fibril specific, conformation dependent antibodies recognize a generic epitope common to amyloid fibrils and fibrillar oligomers that is absent in prefibrillar oligomers

    Directory of Open Access Journals (Sweden)

    Rasool Suhail

    2007-09-01

    Full Text Available Abstract Background Amyloid-related degenerative diseases are associated with the accumulation of misfolded proteins as amyloid fibrils in tissue. In Alzheimer disease (AD, amyloid accumulates in several distinct types of insoluble plaque deposits, intracellular Aβ and as soluble oligomers and the relationships between these deposits and their pathological significance remains unclear. Conformation dependent antibodies have been reported that specifically recognize distinct assembly states of amyloids, including prefibrillar oligomers and fibrils. Results We immunized rabbits with a morphologically homogeneous population of Aβ42 fibrils. The resulting immune serum (OC specifically recognizes fibrils, but not random coil monomer or prefibrillar oligomers, indicating fibrils display a distinct conformation dependent epitope that is absent in prefibrillar oligomers. The fibril epitope is also displayed by fibrils of other types of amyloids, indicating that the epitope is a generic feature of the polypeptide backbone. The fibril specific antibody also recognizes 100,000 × G soluble fibrillar oligomers ranging in size from dimer to greater than 250 kDa on western blots. The fibrillar oligomers recognized by OC are immunologically distinct from prefibrillar oligomers recognized by A11, even though their sizes overlap broadly, indicating that size is not a reliable indicator of oligomer conformation. The immune response to prefibrillar oligomers and fibrils is not sequence specific and antisera of the same specificity are produced in response to immunization with islet amyloid polypeptide prefibrillar oligomer mimics and fibrils. The fibril specific antibodies stain all types of amyloid deposits in human AD brain. Diffuse amyloid deposits stain intensely with anti-fibril antibody although they are thioflavin S negative, suggesting that they are indeed fibrillar in conformation. OC also stains islet amyloid deposits in transgenic mouse models of type

  19. Information transmission on hybrid networks

    Science.gov (United States)

    Chen, Rongbin; Cui, Wei; Pu, Cunlai; Li, Jie; Ji, Bo; Gakis, Konstantinos; Pardalos, Panos M.

    2018-01-01

    Many real-world communication networks often have hybrid nature with both fixed nodes and moving modes, such as the mobile phone networks mainly composed of fixed base stations and mobile phones. In this paper, we discuss the information transmission process on the hybrid networks with both fixed and mobile nodes. The fixed nodes (base stations) are connected as a spatial lattice on the plane forming the information-carrying backbone, while the mobile nodes (users), which are the sources and destinations of information packets, connect to their current nearest fixed nodes respectively to deliver and receive information packets. We observe the phase transition of traffic load in the hybrid network when the packet generation rate goes from below and then above a critical value, which measures the network capacity of packets delivery. We obtain the optimal speed of moving nodes leading to the maximum network capacity. We further improve the network capacity by rewiring the fixed nodes and by considering the current load of fixed nodes during packets transmission. Our purpose is to optimize the network capacity of hybrid networks from the perspective of network science, and provide some insights for the construction of future communication infrastructures.

  20. Structural and functional characteristics of myocard in patients with different forms of atrial fibrillation

    Directory of Open Access Journals (Sweden)

    L. I. Vasilyeva

    2015-02-01

    Full Text Available Aim. To study structural and functional characteristics of myocard in patients with different forms of atrial fibrillation. Atrial fibrillation is the most prevalent arrhythmia in clinical practice. Atrial fibrillation is a progressive disease: the duration of paroxysms increases over time and paroxysmal atrial fibrillation transforms to persistent, the last one becomes refractory to pharmacological and electrical cardioversion in time and transforms to permanent. So assessment of myocardial remodeling in patients with persistent and permanent atrial fibrillation is very actual. Methods and results. According to the aim of the study 133 patients with persistent atrial fibrillation and 100 patients with permanent atrial fibrillation were included into the study. Echocardiographic parameters of left and right atria function were studied. Conclusion. It was found that patients with persistent and permanent atrial fibrillation are characterized with both left and right atrias remodeling. Remodeling of the atrias is less pronounced in patients with permanent atrial fibrillation in comparison with persistent atrial fibrillation patients and arrhythmia recurrence.

  1. Phosphate and HEPES buffers potently affect the fibrillation and oligomerization mechanism of Alzheimer's Aβ peptide

    International Nuclear Information System (INIS)

    Garvey, Megan; Tepper, Katharina; Haupt, Caroline; Knuepfer, Uwe; Klement, Karolin; Meinhardt, Jessica; Horn, Uwe; Balbach, Jochen; Faendrich, Marcus

    2011-01-01

    Highlights: → Sodium phosphate buffer accelerated Aβ(1-40) nucleation relative to HEPES. → Aβ(1-40) fibrils formed in the two buffers show only minor structural differences. → NMR revealed that Aβ(1-40) histidine residues mediate buffer dependent changes. -- Abstract: The oligomerization of Aβ peptide into amyloid fibrils is a hallmark of Alzheimer's disease. Due to its biological relevance, phosphate is the most commonly used buffer system for studying the formation of Aβ and other amyloid fibrils. Investigation into the characteristics and formation of amyloid fibrils frequently relies upon material formed in vitro, predominantly in phosphate buffers. Herein, we examine the effects on the fibrillation and oligomerization mechanism of Aβ peptide that occur due solely to the influence of phosphate buffer. We reveal that significant differences in amyloid fibrillation are observed due to fibrillation being initiated in phosphate or HEPES buffer (at physiological pH and temperature). Except for the differing buffer ions, all experimental parameters were kept constant. Fibril formation was assessed using fluorescently monitored kinetic studies, microscopy, X-ray fiber diffraction and infrared and nuclear magnetic resonance spectroscopies. Based on this set up, we herein reveal profound effects on the mechanism and speed of Aβ fibrillation. The three histidine residues at positions 6, 13 and 14 of Aβ(1-40) are instrumental in these mechanistic changes. We conclude that buffer plays a more significant role in fibril formation than has been generally acknowledged.

  2. Energy losses of superconducting power transmission cables in the grid

    DEFF Research Database (Denmark)

    Østergaard, Jacob; Okholm, Jan; Lomholt, Karin

    2001-01-01

    One of the obvious motives for development of superconducting power transmission cables is reduction of transmission losses. Loss components in superconducting cables as well as in conventional cables have been examined. These losses are used for calculating the total energy losses of conventional...... as well as superconducting cables when they are placed in the electric power transmission network. It is concluded that high load connections are necessary to obtain energy saving by the use of HTSC cables. For selected high load connections, an energy saving of 40% is expected. It is shown...

  3. Frequent periodic leg movement during sleep is an unrecognized risk factor for progression of atrial fibrillation.

    Directory of Open Access Journals (Sweden)

    Mahek Mirza

    Full Text Available Sleep apnea has been recognized as a factor predisposing to atrial fibrillation recurrence and progression. The effect of other sleep-disturbing conditions on atrial fibrillation progression is not known. We sought to determine whether frequent periodic leg movement during sleep is a risk factor for progression of atrial fibrillation. In this retrospective study, patients with atrial fibrillation and a clinical suspicion of restless legs syndrome who were referred for polysomnography were divided into two groups based on severity of periodic leg movement during sleep: frequent (periodic movement index >35/h and infrequent (≤35/h. Progression of atrial fibrillation to persistent or permanent forms between the two groups was compared using Wilcoxon rank-sum test, chi-square tests and logistic regression analysis. Of 373 patients with atrial fibrillation (77% paroxysmal, 23% persistent, 108 (29% progressed to persistent or permanent atrial fibrillation during follow-up (median, 33 months; interquartile range, 16-50. Compared to patients with infrequent periodic leg movement during sleep (n=168, patients with frequent periodic leg movement during sleep (n=205 had a higher rate of atrial fibrillation progression (23% vs. 34%; p=0.01. Patients with frequent periodic leg movement during sleep were older and predominantly male; however, there were no significant differences at baseline in clinical factors that promote atrial fibrillation progression between both groups. On multivariate analysis, independent predictors of atrial fibrillation progression were persistent atrial fibrillation at baseline, female gender, hypertension and frequent periodic leg movement during sleep. In patients with frequent periodic leg movement during sleep, dopaminergic therapy for control of leg movements in patients with restless legs syndrome reduced risk of atrial fibrillation progression. Frequent leg movement during sleep in patients with restless legs syndrome is

  4. Amyloid Cardiomyopathy in Hereditary Transthyretin V30M Amyloidosis - Impact of Sex and Amyloid Fibril Composition.

    Directory of Open Access Journals (Sweden)

    Sandra Arvidsson

    Full Text Available Transthyretin V30M (ATTR V30M amyloidosis is a phenotypically diverse disease with symptoms ranging from predominant neuropathy to exclusive cardiac manifestations. The aims of this study were to determine the dispersion of the two types of fibrils found in Swedish ATTR V30M patients -Type A consisting of a mixture of truncated and full length ATTR fibrils and type B fibrils consisting of full length fibrils, and to estimate the severity of cardiac dysfunction in relation to fibril composition and sex.Echocardiographic data were analysed in 107 Swedish ATTR V30M patients with their fibril composition determined as either type A or type B. Measurements of left ventricular (LV dimensions and evaluation of systolic and diastolic function including speckle tracking derived strain were performed. Patients were grouped according to fibril type and sex. Multivariate linear regression was utilised to determine factors of significant impact on LV thickness.There was no significant difference in proportions of the two types of fibrils between men and women. In patients with type A fibrils, women had significantly lower median septal (p = 0.007 and posterior wall thicknesses (p = 0.010, lower median LV mass indexed to height (p = 0.008, and higher septal strain (p = 0.037, as compared to males. These differences were not apparent in patients with type B fibrils. Multiple linear regression analysis revealed that fibril type, sex and age all had significant impact on LV septal thickness.This study demonstrates a clear difference between sexes in the severity of amyloid heart disease in ATTR V30M amyloidosis patients. Even though type A fibrils were associated with more advanced amyloid heart disease compared to type B, women with type A fibrils generally developed less cardiac infiltration than men. The differences may explain the better outcome for liver transplanted late-onset female patients compared to males.

  5. Pregnant and breastfeeding women: A priority population for HIV viral load monitoring.

    Science.gov (United States)

    Myer, Landon; Essajee, Shaffiq; Broyles, Laura N; Watts, D Heather; Lesosky, Maia; El-Sadr, Wafaa M; Abrams, Elaine J

    2017-08-01

    Landon Myer and colleagues discuss viral load monitoring for pregnant HIV-positive women and those breastfeeding; ART treatments can suppress viral load and are key to preventing transmission to the child.

  6. Coiled transmission line pulse generators

    Science.gov (United States)

    McDonald, Kenneth Fox

    2010-11-09

    Methods and apparatus are provided for fabricating and constructing solid dielectric "Coiled Transmission Line" pulse generators in radial or axial coiled geometries. The pour and cure fabrication process enables a wide variety of geometries and form factors. The volume between the conductors is filled with liquid blends of monomers, polymers, oligomers, and/or cross-linkers and dielectric powders; and then cured to form high field strength and high dielectric constant solid dielectric transmission lines that intrinsically produce ideal rectangular high voltage pulses when charged and switched into matched impedance loads. Voltage levels may be increased by Marx and/or Blumlein principles incorporating spark gap or, preferentially, solid state switches (such as optically triggered thyristors) which produce reliable, high repetition rate operation. Moreover, these Marxed pulse generators can be DC charged and do not require additional pulse forming circuitry, pulse forming lines, transformers, or an a high voltage spark gap output switch. The apparatus accommodates a wide range of voltages, impedances, pulse durations, pulse repetition rates, and duty cycles. The resulting mobile or flight platform friendly cylindrical geometric configuration is much more compact, light-weight, and robust than conventional linear geometries, or pulse generators constructed from conventional components. Installing additional circuitry may accommodate optional pulse shape improvements. The Coiled Transmission Lines can also be connected in parallel to decrease the impedance, or in series to increase the pulse length.

  7. Dronedarone attenuates the duration of atrial fibrillation in a dog model of sustained atrial fibrillation.

    Science.gov (United States)

    Saengklub, Nakkawee; Limprasutr, Vudhiporn; Sawangkoon, Suwanakiet; Hamlin, Robert L; Kijtawornrat, Anusak

    2017-08-05

    Atrial fibrillation (AF) is a supraventricular arrhythmia that leads to a decrease in cardiac output and impairs cardiac function and quality of life. Dronedarone has an atrial-selective property and has been used for management of AF in humans, but limited information is available in dogs. This study was designed to evaluate efficacy of dronedarone in attenuating the duration of AF in dog model of sustained AF. Six beagle dogs were anesthetized with isoflurane and instrumented to measure atrial action potential duration (aAPD) and atrial effective refractory period (AERP). Then AF was induced by rapid right atrial pacing (20 V, 40 Hz) simultaneously with infusion of phenylephrine (2 µg/kg/min, intravenously) for 20 min. The duration of sustained AF was recorded, and the animals were allowed to recover. Dronedarone was given at a dose of 20 mg/kg, BID, orally for 7 days. On the last day, the dogs were anesthetized again to record aAPD and AERP, and AF was induced with the same procedure as described above. The results showed that after dronedarone administration the aAPD was lengthened significantly from 76.4 ± 4.2 ms to 91.2 ± 3.9 ms (Pdog model of AF by extending the AERP more than the aAPD, causing post-repolarization refractoriness. Hence, dronedarone may be useful for management of AF in dogs.

  8. Family history of atrial fibrillation is associated with earlier-onset and more symptomatic atrial fibrillation

    DEFF Research Database (Denmark)

    Gundlund, Anna; Fosbøl, Emil Loldrup; Kim, Sunghee

    2016-01-01

    BACKGROUND: We addressed whether patients with a family history of atrial fibrillation (AF) were diagnosed as having AF earlier in life, were more symptomatic, and had worse outcomes compared with those without a family history of AF. METHODS: Using the ORBIT-AF, we compared symptoms and disease......, and had more severe AF-related symptoms. No differences were found between the 2 groups in the risk of AF progression (adjusted hazard ratio [HR] 0.98, 95% CI 0.85-1.14), stroke, non-central nervous system embolism, or transient ischemic attack (adjusted HR 0.95, 95% CI 0.67-1.34), all......-cause hospitalization (adjusted HR 1.03, 95% CI 0.94-1.12), and all-cause death (adjusted HR 1.05, 95% CI 0.86-1.27). CONCLUSIONS: Patients with a family history of AF developed AF at a younger age, had less comorbidity, and were more symptomatic. Once AF developed, no significantly increased risks of AF progression...

  9. The automotive transmission book

    CERN Document Server

    Fischer, Robert; Jürgens, Gunter; Najork, Rolf; Pollak, Burkhard

    2015-01-01

    This book presents essential information on systems and interactions in automotive transmission technology and outlines the methodologies used to analyze and develop transmission concepts and designs. Functions of and interactions between components and subassemblies of transmissions are introduced, providing a basis for designing transmission systems and for determining their potentials and properties in vehicle-specific applications: passenger cars, trucks, buses, tractors, and motorcycles. With these fundamentals the presentation provides universal resources for both state-of-the-art and future transmission technologies, including systems for electric and hybrid electric vehicles.

  10. Patient load effects on response time to critical arrhythmias in cardiac telemetry: a randomized trial.

    Science.gov (United States)

    Segall, Noa; Hobbs, Gene; Granger, Christopher B; Anderson, Amanda E; Bonifacio, Alberto S; Taekman, Jeffrey M; Wright, Melanie C

    2015-05-01

    Remotely monitored patients may be at risk for a delayed response to critical arrhythmias if the telemetry watchers who monitor them are subject to an excessive patient load. There are no guidelines or studies regarding the appropriate number of patients that a single watcher may safely and effectively monitor. Our objective was to determine the impact of increasing the number of patients monitored on response time to simulated cardiac arrest. Randomized trial. Laboratory-based experiment. Forty-two remote telemetry technicians and nurses from cardiac units. Number of patients monitored in a simulation of cardiac telemetry monitoring work. We carried out a study to compare response times to ventricular fibrillation across five patient loads: 16, 24, 32, 40, and 48 patients. The simulation replicated the work of telemetry watchers using a combination of real recorded patient electrocardiogram signals and a simulated patient experiencing ventricular fibrillation. Study participants were assigned to one of the five patient loads and completed a 4-hour monitoring session, during which they performed tasks-including event documentation and phone calls to report events-similar to real monitoring work. When the simulated patient sustained ventricular fibrillation, the time required to report this arrhythmia was recorded. As patient loads increased, there was a statistically significant increase in response times to the ventricular fibrillation. In addition, frequency of failure to meet a response time goal of less than 20 seconds was significantly higher in the 48-patient condition than in all other conditions. Task performance decreased as patient load increased. As participants monitored more patients in a laboratory setting, their performance with respect to recognizing critical and noncritical events declined. This study has implications for the design of remote telemetry work and other patient monitoring tasks in critical and intermediate care units.

  11. Rapid biomimetic mineralization of collagen fibrils and combining with human umbilical cord mesenchymal stem cells for bone defects healing

    International Nuclear Information System (INIS)

    Ye, Bihua; Luo, Xueshi; Li, Zhiwen; Zhuang, Caiping; Li, Lihua; Lu, Lu; Ding, Shan; Tian, Jinhuan; Zhou, Changren

    2016-01-01

    Collagen biomineralization is regulated by complicated interactions between the collagen matrix and non-collagenous extracellular proteins. Here, the use of sodium tripolyphosphate to simulate the templating functional motif of the C-terminal fragment of non-collagenous proteins is reported, and a low molecular weight polyacrylic acid served as a sequestration agent to stabilize amorphous calcium phosphate into nanoprecursors. Self-assembled collagen fibrils served as a fixed template for achieving rapid biomimetic mineralization in vitro. Results demonstrated that, during the mineralization process, intrafibrillar and extrafibrillar hydroxyapatite mineral with collagen fibrils formed and did so via bottom-up nanoparticle assembly based on the non-classical crystallization approach in the presence of these dual biomimetic functional analogues. In vitro human umbilical cord mesenchymal stem cell (hUCMSC) culture found that the mineralized scaffolds have a better cytocompatibility in terms of cell viability, adhesion, proliferation, and differentiation into osteoblasts. A rabbit femoral condyle defect model was established to confirm the ability of the n-HA/collagen scaffolds to facilitate bone regeneration and repair. The images of gross anatomy, MRI, CT and histomorphology taken 6 and 12 weeks after surgery showed that the biomimetic mineralized collagen scaffolds with hUCMSCs can promote the healing speed of bone defects in vivo, and both of the scaffolds groups performing better than the bone defect control group. As new bone tissue formed, the scaffolds degraded and were gradually absorbed. All these results demonstrated that both of the scaffolds and cells have better histocompatibility. - Highlights: • A rapid and facile biomimetic mineralization approach is proposed. • Intrafibrillar and extrafibrillar mineralization of collagen fibrils was achieved. • HA/COL scaffolds promote hUCMSCs adhesion, proliferation, and differentiation. • Feasibility of h

  12. Automated manual transmission controller

    Science.gov (United States)

    Lawrie, Robert E.; Reed, Jr., Richard G.; Bernier, David R.

    1999-12-28

    A powertrain system for a hybrid vehicle. The hybrid vehicle includes a heat engine, such as a diesel engine, and an electric machine, which operates as both an electric motor and an alternator, to power the vehicle. The hybrid vehicle also includes a manual-style transmission configured to operate as an automatic transmission from the perspective of the driver. The engine and the electric machine drive an input shaft which in turn drives an output shaft of the transmission. In addition to driving the transmission, the electric machine regulates the speed of the input shaft in order to synchronize the input shaft during either an upshift or downshift of the transmission by either decreasing or increasing the speed of the input shaft. When decreasing the speed of the input shaft, the electric motor functions as an alternator to produce electrical energy which may be stored by a storage device. Operation of the transmission is controlled by a transmission controller which receives input signals and generates output signals to control shift and clutch motors to effect smooth launch, upshift shifts, and downshifts of the transmission, so that the transmission functions substantially as an automatic transmission from the perspective of the driver, while internally substantially functioning as a manual transmission.

  13. Vertebrae length and ultra-structure measurements of collagen fibrils and mineral content in the vertebrae of lordotic gilthead seabreams (Sparus aurata).

    Science.gov (United States)

    Berillis, Panagiotis; Panagiotopoulos, Nikolaos; Boursiaki, Vaia; Karapanagiotidis, Ioannis T; Mente, Eleni

    2015-08-01

    Skeletal deformities of gilthead seabream (Sparus aurata) are a major factor affecting the production cost, the external morphology and survival and growth of the fish. Adult individuals of S. aurata were collected from a commercial fish farm in Greece and were divided into two groups: one with the presence of lordosis, a skeletal deformity, and one without any skeletal deformity. Fishes were X-rayed, and cervical, abdominal and caudal vertebrae lengths were measured. Vertebrae were taken from the site of the vertebral column where lordosis occurred. One part was decalcified and prepared for collagen examination with transmission electron microscopy, and the rest were incinerated, and the Ca and P contents were measured. The stoichiometries of the samples were obtained by EDS (Energy Dispersive Spectroscopy). The same procedure was followed for fish without skeletal deformities (vertebrae were taken from the middle region of the vertebral column). The decalcified vertebrae parts were examined with TEM, collagen micrographs were taken and the fibrils' periods and diameters were measured. There were no significant differences for both Ca and P or the collagen fibrils' periods between the two fish groups. The mean lengths of the cervical, abdominal and caudal vertebrae where lordosis occurred were similar to the lengths of the respective regions of the individuals without the skeletal deformity. The TEM examination showed a significantly smaller mean vertebrae collagen fibril diameter from the fishes with lordosis compared with those from the controls, revealing the significance of collagen to bone structure. Copyright © 2015 Elsevier Ltd. All rights reserved.

  14. Effect of fibril shape on adhesive properties

    Science.gov (United States)

    Soto, Daniel; Hill, Ginel; Parness, Aaron; Esparza, Noé; Cutkosky, Mark; Kenny, Tom

    2010-08-01

    Research into the gecko's adhesive system revealed a unique architecture for adhesives using tiny hairs. By using a stiff material (β-keratin) to create a highly structured adhesive, the gecko's system demonstrates properties not seen in traditional pressure-sensitive adhesives which use a soft, unstructured planar layer. In contrast to pressure sensitive adhesives, the gecko adhesive displays frictional adhesion, in which increased shear force allows it to withstand higher normal loads. Synthetic fibrillar adhesives have been fabricated but not all demonstrate this frictional adhesion property. Here we report the dual-axis force testing of single silicone rubber pillars from synthetic adhesive arrays. We find that the shape of the adhesive pillar dictates whether frictional adhesion or pressure-sensitive behavior is observed. This work suggests that both types of behavior can be achieved with structures much larger than gecko terminal structures. It also indicates that subtle differences in the shape of these pillars can significantly influence their properties.

  15. Work related physical activity and risk of a hospital discharge diagnosis of atrial fibrillation or flutter

    DEFF Research Database (Denmark)

    Frost, L; Frost, P; Vestergaard, P

    2005-01-01

    BACKGROUND AND AIMS: Excessive sporting activities have been associated with risk of atrial fibrillation. To study if work related physical activity also confers risk of atrial fibrillation or flutter, the association between work related physical strain and the risk of a hospital discharge...... (mean 5.7 years) a hospital discharge diagnosis of atrial fibrillation or flutter occurred in 305 men and 113 women. When using the risk of atrial fibrillation or flutter associated with sedentary work at a sitting position as a reference, no excess risk (unadjusted as well as adjusted) was found...... of atrial fibrillation or flutter associated with sedentary work in a standing position, light workload, or heavy workload in men or women. CONCLUSION: No evidence was found of an association between physical activities during working hours and risk of a hospital discharge diagnosis of atrial fibrillation...

  16. Synergistic Inhibition of Protein Fibrillation by Proline and Sorbitol: Biophysical Investigations.

    Directory of Open Access Journals (Sweden)

    Sinjan Choudhary

    Full Text Available We report here interesting synergistic effects of proline and sorbitol, two well-known chemical chaperones, in the inhibition of fibrillation of two proteins, insulin and lysozyme. A combination of many biophysical techniques has been used to understand the structural morphology and modes of interaction of the chaperones with the proteins during fibrillation. Both the chaperones establish stronger polar interactions in the elongation and saturation stages of fibrillation compared to that in the native stage. However, when presented as a mixture, we also see contribution of hydrophobic interactions. Thus, a co-operative adjustment of polar and hydrophobic interactions between the chaperones and the protein surface seems to drive the synergistic effects in the fibrillation process. In insulin, this synergy is quantitatively similar in all the stages of the fibrillation process. These observations would have significant implications for understanding protein folding concepts, in general, and for designing combination therapies against protein fibrillation, in particular.

  17. Disulfide bridges remain intact while native insulin converts into amyloid fibrils.

    Directory of Open Access Journals (Sweden)

    Dmitry Kurouski

    Full Text Available Amyloid fibrils are β-sheet-rich protein aggregates commonly found in the organs and tissues of patients with various amyloid-associated diseases. Understanding the structural organization of amyloid fibrils can be beneficial for the search of drugs to successfully treat diseases associated with protein misfolding. The structure of insulin fibrils was characterized by deep ultraviolet resonance Raman (DUVRR and Nuclear Magnetic Resonance (NMR spectroscopy combined with hydrogen-deuterium exchange. The compositions of the fibril core and unordered parts were determined at single amino acid residue resolution. All three disulfide bonds of native insulin remained intact during the aggregation process, withstanding scrambling. Three out of four tyrosine residues were packed into the fibril core, and another aromatic amino acid, phenylalanine, was located in the unordered parts of insulin fibrils. In addition, using all-atom MD simulations, the disulfide bonds were confirmed to remain intact in the insulin dimer, which mimics the fibrillar form of insulin.

  18. Changes in plasma atrial natriuretic factor in patients with idiopathic atrial fibrillation

    International Nuclear Information System (INIS)

    Du Tongxin; Xia Xiaojie; Qu Wei; Wang Shukui; Sun Junjiang

    2002-01-01

    To observe the changes in plasma atrial natriuretic factor (AFN) in patients with idiopathic atrial fibrillation and investigate its mechanism, plasma ANF, platelet count and hematocrit were detected in 21 cases with transient idiopathic atrial fibrillation (group A, A1 representing attack, while A2 termination), 28 with persistent idiopathic atrial fibrillation (group B), 27 suffered from rheumatic heart disease with mitral stenosis and persistent atrial fibrillation (group C), 32 with transient supraventricular tachycardia (group D) and 20 normal controls (group E). It was found that the level of ANF was significantly higher in patients with attacking transient idiopathic atrial fibrillation than that in group A2, D and E (P 0.05), while there was significant difference in hematocrit in group A1 compared with group A2, D, E (P < 0.01). It suggested that ANF and hematocrit play an important role in the attack of idiopathic atrial fibrillation

  19. Unexpected guest: Atrial fibrillation due to electrical shock

    Directory of Open Access Journals (Sweden)

    Mehmet Zihni Bilik

    2016-03-01

    Full Text Available Cardiac arrhythmias due to electrical injuries are rare among emergency service admittances. A 35 year-old female patient was admitted to emergency service with palpitation after electrical injury as a result of contact with a domestic low-voltage source. Electrocardiography (ECG showed atrial fibrillation with rapid ventricular response. Transthoracic echocardiography findings were normal. Atrial fibrillation spontaneously converted to normal sinus rhythm after rate limiting treatment with beta-blocker. The patient was discharged without any complication on the third day of hospitalization. Although cardiac arrhythmias rarely occur after electrical injury, cardiac monitoring is recommended for all patients with documented rhythm disorder, loss of consciousness, or abnormal ECG at admission.

  20. Prognostic importance of atrial fibrillation in asymptomatic aortic stenosis

    DEFF Research Database (Denmark)

    Greve, Anders; Gerdts, Eva; Boman, Kurt

    2013-01-01

    BACKGROUND: The frequency and prognostic importance of atrial fibrillation (AF) in asymptomatic mild-to-moderate aortic stenosis (AS) has not been well described. METHODS: Clinical examination, electrocardiography and echocardiography were obtained in asymptomatic patients with mild-to-moderate A......BACKGROUND: The frequency and prognostic importance of atrial fibrillation (AF) in asymptomatic mild-to-moderate aortic stenosis (AS) has not been well described. METHODS: Clinical examination, electrocardiography and echocardiography were obtained in asymptomatic patients with mild......-to-moderate AS and preserved left ventricular (LV) systolic function, randomized to simvastatin/ezetimibe combination vs. placebo in the Simvastatin and Ezetimibe in Aortic Stenosis (SEAS) study. At inclusion, AF was categorized as episodic or longstanding. Rhythm change was assessed on annual in-study electrocardiograms...

  1. [Novel anticoagulants for stroke prevention in atrial fibrillation].

    Science.gov (United States)

    Baumhäkel, M; Schirmer, S H; Böhm, M

    2010-11-01

    The most frequent cardiac arrhythmia and main cause for cardio-embolic stroke is atrial fibrillation. Prophylaxis for thrombembolic events is performed regarding individual risk of patients with either ASS or vitamin-K-antagonists. Efficacy and safety of oral anticoagulation is limited by a narrow therapeutical range as well as by inter- and intraindividual variability of INR-values due to genetic disposition, differences in alimentation, dosage errors, rare control of INR-levels and drug-interactions. New oral anticoagulants with different mechanisms of action may be a promising therapeutic option in future. This review addresses the new anticoagulants Apixaban, Rivaroxban and Dabigatranetexilat with the design and as available the results of the corresponding phase-III-trials in atrial fibrillation (ARISTOTLE, ROCKET-AF, RE-LY). © Georg Thieme Verlag KG Stuttgart · New York.

  2. Dynamical mechanism of atrial fibrillation: A topological approach

    Science.gov (United States)

    Marcotte, Christopher D.; Grigoriev, Roman O.

    2017-09-01

    While spiral wave breakup has been implicated in the emergence of atrial fibrillation, its role in maintaining this complex type of cardiac arrhythmia is less clear. We used the Karma model of cardiac excitation to investigate the dynamical mechanisms that sustain atrial fibrillation once it has been established. The results of our numerical study show that spatiotemporally chaotic dynamics in this regime can be described as a dynamical equilibrium between topologically distinct types of transitions that increase or decrease the number of wavelets, in general agreement with the multiple wavelets' hypothesis. Surprisingly, we found that the process of continuous excitation waves breaking up into discontinuous pieces plays no role whatsoever in maintaining spatiotemporal complexity. Instead, this complexity is maintained as a dynamical balance between wave coalescence—a unique, previously unidentified, topological process that increases the number of wavelets—and wave collapse—a different topological process that decreases their number.

  3. [Lone atrial fibrillation--relevance for medical underwriting].

    Science.gov (United States)

    Filzmaier, K

    2013-09-01

    Atrial fibrillation is a common and multifaceted cardiac arrhythmia. At present rhythm and rate control can be considered equal regarding morbidity and mortality. Following scientific findings in the past years new therapeutic strategies and treatment options were developed. Therefore, a decision must be made not only between rate and rhythm control but also between the different antithrombotic drug regimes. Oral thrombin and factor X inhibitors herald a new era in antithrombotic therapy. The lack of necessity for routine INR monitoring certainly constitutes one of the greatest advantages of these novel agents in everyday clinical practice. Pulmonary vein isolation is a catheter-based treatment option for atrial fibrillation enabling the cure of arrhythmias for many patients--despite the high rate of recurrence. Many of these new therapeutical options lack long-term findings and previous successes are to be regarded with certain prudence.

  4. Obesity, Diabetes and Atrial Fibrillation; Epidemiology, Mechanisms and Interventions

    OpenAIRE

    Asghar, O; Alam, U; Hayat, SA; Aghamohammadzadeh, R; Heagerty, AM; Malik, RA

    2012-01-01

    The last few decades have witnessed a global rise in adult obesity of epidemic proportions. The potential impact of this is emphasized when one considers that body mass index (BMI) is a powerful predictor of death, type 2 diabetes (T2DM) and cardiovascular (CV) morbidity and mortality [1, 2]. Similarly we have witnessed a parallel rise in the incidence of atrial fibrillation (AF), the commonest sustained cardiac arrhythmia, which is also a significant cause of cardiovascular morbidity and mor...

  5. Inflammation in the genesis and perpetuation of atrial fibrillation

    DEFF Research Database (Denmark)

    Engelmann, Mads D M; Svendsen, Jesper Hastrup

    2005-01-01

    The prevalence and persistence of atrial fibrillation (AF) and the relative inefficacy of the currently available pharmacotherapy requires development of new treatment strategies. Recent findings have suggested a mechanistic link between inflammatory processes and the development of AF. Epidemiol...... be through anti-inflammatory activity. This article reviews what is known about inflammation in genesis and perpetuation of AF, the putative underlying mechanisms, and possible therapeutic implications for the inhibition of inflammation as an evolving treatment modality for AF....

  6. The World Heart Federation Roadmap for Nonvalvular Atrial Fibrillation.

    OpenAIRE

    Murphy, A; Banerjee, A; Breithardt, G; Camm, AJ; Commerford, P; Freedman, B; Gonzalez-Hermosillo, JA; Halperin, JL; Lau, C-P; Perel, P; Xavier, D; Wood, D; Jouven, X; Morillo, CA

    2017-01-01

    BACKGROUND: The World Heart Federation has undertaken an initiative to develop a series of Roadmaps to promote development of national policies and health systems approaches, and to identify potential roadblocks on the road to effective prevention, detection, and management of cardiovascular disease in low-and middle-income countries (LMICs) and develop strategies for overcoming these. This Roadmap focuses on atrial fibrillation (AF). AF is the most common, clinically significant arrhythmia a...

  7. The Word Heart Federation Roadmap for Nonvalvular Atrial Fibrillation

    OpenAIRE

    Murphy, A.; Banerjee, A.; Breithardt, G.; Camm, A. J.; Commerford, P.; Freedman, B.; Gonzalez-Hermosillo, J. A.; Halperin, J. L.; Lau, C. P.; Perel, P.; Xavier, D.; Wood, D.; Jouven, X.; Morillo, C. A.

    2017-01-01

    BACKGROUND: The World Heart Federation has undertaken an initiative to develop a series of Roadmaps to promote development of national policies and health systems approaches, and to identify potential roadblocks on the road to effective prevention, detection, and management of cardiovascular disease in low-and middle-income countries (LMICs) and develop strategies for overcoming these. This Roadmap focuses on atrial fibrillation (AF). AF is the most common, clinically significant arrhythmia a...

  8. Catapult launch-associated cardioversion of atrial fibrillation.

    Science.gov (United States)

    Bohnker, B K; Feeks, E F; McEwen, G

    1993-10-01

    A patient is presented with new-onset atrial fibrillation. While being air-evacuated, he cardioverted during the acceleration associated with aircraft carrier catapult launch. This case suggests a possible myocardial response to the kinetic energy produced by the acceleration force, similar to the electrical energy commonly used for cardioversion. Cardioversion using acceleration forces is probably not a clinically useful modality; however, this case demonstrates the importance of acceleration forces on patients during medical evacuation from aircraft carriers.

  9. Slow ventricular response atrial fibrillation related to mad honey poisoning

    Science.gov (United States)

    Osken, A.; Yaylacı, S.; Aydın, E.; Kocayigit, İ; Cakar, M.A.; Tamer, A.; Gündüz, H.

    2012-01-01

    Mad honey poisoning which is induced by Grayanotoxin (Andromedotoxin), is also known to have adverse effects in the cardiovascular system leading to different clinical entities. This toxin is produced by a member of the Rhododendron genus of plants of two R. Luteum and R. Panticum. In this article, we presented a case of slow ventricular response atrial fibrillation complaints with nausea, vomiting, dizziness and chest pain about an hour after eating honey produced in the Black Sea Region. PMID:22923947

  10. Slow ventricular response atrial fibrillation related to mad honey poisoning

    OpenAIRE

    Osken, A.; Yaylacı, S.; Aydın, E.; Kocayigit, İ; Cakar, M.A.; Tamer, A.; Gündüz, H.

    2012-01-01

    Mad honey poisoning which is induced by Grayanotoxin (Andromedotoxin), is also known to have adverse effects in the cardiovascular system leading to different clinical entities. This toxin is produced by a member of the Rhododendron genus of plants of two R. Luteum and R. Panticum. In this article, we presented a case of slow ventricular response atrial fibrillation complaints with nausea, vomiting, dizziness and chest pain about an hour after eating honey produced in the Black Sea Region.

  11. Peptide fibrils with altered stability, activity, and cell selectivity

    OpenAIRE

    Chen, Long; Liang, Jun F.

    2013-01-01

    Peptides have some unique and superior features compared to proteins. However, the use of peptides as therapeutics is hampered by their low stability and cell selectivity. In this study, a new lytic peptide (CL-1, FLGALFRALSRLL) was constructed. Under the physiological condition, peptide CL-1 self-assembled into dynamically stable aggregates with fibrils-like structures. Aggregated CL-1 demonstrated dramatically altered activity and stability in comparison with single molecule CL-1 and other ...

  12. Fibril morphology and tendon mechanical properties in patellar tendinopathy: effects of heavy slow resistance training

    DEFF Research Database (Denmark)

    Kongsgaard, Mads; Qvortrup, Klaus; Larsen, Jytte Overgaard

    2010-01-01

    BACKGROUND: Patellar tendinopathy is characterized by pathologic abnormalities. Heavy slow resistance training (HSR) is effective in the management of patellar tendinopathy, but the underlying functional mechanisms remain elusive. PURPOSE: To investigate fibril morphology and mechanical properties...... area. Heavy slow resistance training improved the clinical outcome of patellar tendinopathy, and these improvements were associated with normalization of fibril morphology, most likely due to a production of new fibrils....

  13. Left Atrial Linear Ablation of Paroxysmal Atrial Fibrillation Guided by Three-dimensional Electroanatomical System

    DEFF Research Database (Denmark)

    Zhang, Dai-Fu; Li, Ying; Qi, Wei-Gang

    2005-01-01

    Objective To investigate the safety and efficacy of Left atrial linear ablation of paroxysmal atrial fibrillation guided by three-dimensional electroanatomical system. Methods 29 patients with paroxysmal atrial fibrillation in this study. A nonfluoroscopic mapping system was used to generate a 3D...... attacks unchanged. No pulmonary vein narrowing was observed. Conclusion Left atrial linear ablation of paroxysmal atrial fibrillation guided by three-dimensional electroanatomical system was safe and effective....

  14. Microscopic structural study of collagen aging in isolated fibrils using polarized second harmonic generation

    Science.gov (United States)

    Aït-Belkacem, Dora; Guilbert, Marie; Roche, Muriel; Duboisset, Julien; Ferrand, Patrick; Sockalingum, Ganesh; Jeannesson, Pierre; Brasselet, Sophie

    2012-08-01

    Polarization resolved second harmonic generation (PSHG) is developed to study, at the microscopic scale, the impact of aging on the structure of type I collagen fibrils in two-dimensional coatings. A ribose-glycated collagen is also used to mimic tissue glycation usually described as an indicator of aging. PSHG images are analyzed using a generic approach of the molecular disorder information in collagen fibrils, revealing significant changes upon aging, with a direct correlation between molecular disorder and fibril diameters.

  15. [Atrial fibrillation as consequence and cause of structural changes of atria].

    Science.gov (United States)

    Aparina, O P; Chikhireva, L N; Stukalova, O V; Mironova, N A; Kashtanova, S Iu; Ternovoĭ, S K; Golitsyn, S P

    2014-01-01

    Changes of atrial structure and function are the contributors of atrial fibrillation clinical course, complications and treatment effectiveness. Effects of inflammation and mechanical stretch on atrial structural remodeling leading to atrial fibrillation are reviewed in the article. Contemporary invasive and non-invasive methods of evaluation (including late gadolinium enhancement magnetic resonance imaging) of patients with atrial structural remodeling in atrial fibrillation are also described.

  16. The impact of binding of macrocyclic metal complexes on amyloid fibrillization of insulin and lysozyme.

    Science.gov (United States)

    Kovalska, Vladyslava; Chernii, Svitlana; Cherepanov, Vsevolod; Losytskyy, Mykhaylo; Chernii, Victor; Varzatskii, Oleg; Naumovets, Anton; Yarmoluk, Sergiy

    2017-08-01

    Amyloid fibrils are insoluble protein aggregates whose accumulation in cells and tissues is connected with a range of pathological diseases. We studied the impact of 2 metal complexes (axially coordinated Hf phthalocyanine and iron (II) clathrochelate) on aggregation of insulin and lysozyme. For both proteins, the host-guest interaction with these compounds changes the kinetics of fibrillization and affects the morphology of final aggregates. The Hf phthalocyanine is a very efficient inhibitor of insulin fibrillization; in its presence, only very low amounts of fibrils with the diameters of 0.8 to 5 nm and spherical aggregates were found. Effective concentration of fibrillization inhibition (IC 50 ) was estimated to be 0.11 ± 0.04 μM. The clathrochelate induced the formation of thin fibrils with the diameters of 0.8 to 2.5 nm; IC 50 was estimated as 20 ± 9 μM. The lysozyme fibrillization remained quite intensive in the presence of the studied compounds; they induced the formation of long filaments (the length up to 2.5 μm, the diameters of 1.5-3.5 nm). These fibrils noticeably differed from those of free lysozyme short linear species (the diameters of 3-5 nm, the length up to 0.6 μm). Thinning and elongation of fibrils suggest that the metal complexes bind mainly to the grooves of protofilaments; this hinders the stacking of early aggregates or protofilaments together but does not hinder their growth. The image of the fibril separated into 2 protofilaments allows suggesting that the fibril formation occurs via the growth of the parallel protofilaments with their subsequent twisting in the fibril. The changes of the lysozyme intrinsic fluorescence indicate that both metal complexes interact with the protein during the stage of the fibrillar seeds formation. Copyright © 2017 John Wiley & Sons, Ltd.

  17. Streptococcus salivarius strains carry either fibrils or fimbriae on the cell surface.

    Science.gov (United States)

    Handley, P S; Carter, P L; Fielding, J

    1984-01-01

    Strains of Streptococcus salivarius were screened by negative staining for the presence of surface structures. Two structural subgroups were found, carrying either fibrils or fimbriae, projecting from the cell surface. Eight strains carried a very dense peritrichous array of fibrils of two distinct lengths. Long fibrils had an average length of 175 nm, and short fibrils had an average length of 95 nm. Two strains carried only long fibrils, one strain carried only short fibrils, and another strain carried a lateral tuft of very prominent fibrils of two lengths, with a fibrillar fuzz covering the remainder of the cell surface. In all the strains in which they were present, the long fibrils were unaffected by protease or trypsin treatment. In contrast, the short fibrils were completely digested by protease and partially removed by trypsin. Neither long nor short fibrils were affected structurally by mild pepsin digestion or by lipase. The Lancefield extraction procedure removed both long and short fibrils. These twelve fibrillar strains were therefore divisible into four structural subgroups. Extracts of all the fibrillar strains reacted with group K antiserum. The second main structural subgroup consisted of nine strains of S. salivarius, all of which carried morphologically identical, flexible fimbriae arranged peritrichously over the cell surface. The fimbriae were structurally distinct from fibrils and measured 0.5 to 1.0 micron long and 3 to 4 nm wide, with an irregular outline and no obvious substructure. There was no obvious reduction in the number of fimbriae after protease or trypsin treatment. Extracts of the fimbriated strains did not react with the group K antiserum. The two serological and structural subgroups could also be distinguished by colony morphology. Images PMID:6197404

  18. Morphological development of cellulose fibrils of a bleached eucalyptus pulp by mechanical fibrillation

    Science.gov (United States)

    Q.Q. Wang; J.Y. Zhu; R. Gleisner; T.A. Kuster; U. Baxa; S.E. McNeil

    2012-01-01

    This study reports the production of cellulose nanofibrils (CNF) from a bleached eucalyptus pulp using a commercial stone grinder. Scanning electronic microscopy and transmission electronic microscopy imaging were used to reveal morphological development of CNF at micro and nano scales, respectively. Two major structures were identified (1) highly kinked, naturally...

  19. Accurate, Automated Detection of Atrial Fibrillation in Ambulatory Recordings

    Science.gov (United States)

    Linker, David T.

    2016-01-01

    Purpose A highly accurate, automated algorithm would facilitate cost-effective screening for asymptomatic atrial fibrillation. This study analyzed a new algorithm and compared to existing techniques. Methods The incremental benefit of each step in refinement of the algorithm was measured, and the algorithm was compared to other methods using the Physionet atrial fibrillation and normal sinus rhythm databases. Results When analyzing segments of 21 RR intervals or less, the algorithm had a significantly higher area under the receiver operating characteristic curve (AUC) than the other algorithms tested. At analysis segment sizes of up to 101 RR intervals, the algorithm continued to have a higher AUC than any of the other methods tested, although the difference from the second best other algorithm was no longer significant, with an AUC of 0.9992 with a 95% confidence interval (CI) of 0.9986–0.9998, versus 0.9986 (CI 0.9978–0.9994). With identical per-subject sensitivity, per-subject specificity of the current algorithm was superior to the other tested algorithms even at 101 RR intervals, with no false positives (CI 0.0%–0.8%) versus 5.3% false positives for the second best algorithm (CI 3.4–7.9%). Conclusions The described algorithm shows great promise for automated screening for atrial fibrillation by reducing false positives requiring manual review, while maintaining high sensitivity. PMID:26850411

  20. Artificial Intelligence Methods Applied to Parameter Detection of Atrial Fibrillation

    Science.gov (United States)

    Arotaritei, D.; Rotariu, C.

    2015-09-01

    In this paper we present a novel method to develop an atrial fibrillation (AF) based on statistical descriptors and hybrid neuro-fuzzy and crisp system. The inference of system produce rules of type if-then-else that care extracted to construct a binary decision system: normal of atrial fibrillation. We use TPR (Turning Point Ratio), SE (Shannon Entropy) and RMSSD (Root Mean Square of Successive Differences) along with a new descriptor, Teager- Kaiser energy, in order to improve the accuracy of detection. The descriptors are calculated over a sliding window that produce very large number of vectors (massive dataset) used by classifier. The length of window is a crisp descriptor meanwhile the rest of descriptors are interval-valued type. The parameters of hybrid system are adapted using Genetic Algorithm (GA) algorithm with fitness single objective target: highest values for sensibility and sensitivity. The rules are extracted and they are part of the decision system. The proposed method was tested using the Physionet MIT-BIH Atrial Fibrillation Database and the experimental results revealed a good accuracy of AF detection in terms of sensitivity and specificity (above 90%).

  1. Imaging and quantification of amyloid fibrillation in the cell nucleus.

    Science.gov (United States)

    Arnhold, Florian; Scharf, Andrea; von Mikecz, Anna

    2015-01-01

    Xenobiotics, as well as intrinsic processes such as cellular aging, contribute to an environment that constantly challenges nuclear organization and function. While it becomes increasingly clear that proteasome-dependent proteolysis is a major player, the topology and molecular mechanisms of nuclear protein homeostasis remain largely unknown. We have shown previously that (1) proteasome-dependent protein degradation is organized in focal microenvironments throughout the nucleoplasm and (2) heavy metals as well as nanoparticles induce nuclear protein fibrillation with amyloid characteristics. Here, we describe methods to characterize the landscape of intranuclear amyloid on the global and local level in different systems such as cultures of mammalian cells and the soil nematode Caenorhabditis elegans. Application of discrete mathematics to imaging data is introduced as a tool to develop pattern recognition of intracellular protein fibrillation. Since stepwise fibrillation of otherwise soluble proteins to insoluble amyloid-like protein aggregates is a hallmark of neurodegenerative protein-misfolding disorders including Alzheimer's disease, CAG repeat diseases, and the prion encephalopathies, investigation of intracellular amyloid may likewise aid to a better understanding of the pathomechanisms involved. We consider aggregate profiling as an important experimental approach to determine if nuclear amyloid has toxic or protective roles in various disease processes.

  2. Avalanche transmission and critical behaviour in load-bearing ...

    Indian Academy of Sciences (India)

    Synchronization, Coupled Systems and Networks Volume 77 Issue 5 November 2011 pp 873-879 ... http://www.ias.ac.in/article/fulltext/pram/077/05/0873-0879 ... The avalanche time distributions of the V-lattice, a unique realization of the networks, show power-law behaviour when tested with certain fractions of its trunk ...

  3. Avalanche transmission and critical behaviour in load-bearing ...

    Indian Academy of Sciences (India)

    explored further. We hope to explore some of these directions in future work. Acknowledgements. AD thanks the University Grants Commission, India, for a fellowship. References. [1] S H Strogatz, Nature (London) 410, 268 (2001). [2] R Albert and A-L Barabási, Rev. Mod. Phys. 74, 47 (2002). [3] S N Coppersmith, C-h Liu, ...

  4. Avalanche transmission and critical behaviour in load-bearing ...

    Indian Academy of Sciences (India)

    It is well known that many important systems such as the World Wide Web and the Internet, power grids and cellular networks ... iM ) takes the value 1 if a connection exists between iM−1 l and iM and. 0 if a connection ... A network of M = 8 layers with eight sites per layer with connection proba- bility p = 1/2. The beaded line ...

  5. Matching problems in pulse power radial transmission lines

    International Nuclear Information System (INIS)

    Mittag, K.; Brandelik, A.

    1984-12-01

    In this report we study the power transfer from a generator along a coaxial transmission line followed by a radial transmission line into a load, which in our application is a pseudo-spark plasma of about one millimeter diameter and about 15 cm in length. First the theoretical background based on transmission line theory is described. Then numerical results are presented. The main conclusion is that when matching the pulse power generator to the pseudo-spark plasma, the effect of the impedance transformation caused by the radial transmission line has to be taken into account. The conditions to obtain an optimal match are described. (orig.) [de

  6. Cost of illness of atrial fibrillation: a nationwide study of societal impact.

    Science.gov (United States)

    Johnsen, Søren Paaske; Dalby, Lene Worsaae; Täckström, Tomas; Olsen, Jens; Fraschke, Anina

    2017-11-10

    The prevalence of atrial fibrillation is increasing rapidly; however, to date, population-based data are lacking on the attributable cost of illness of atrial fibrillation from a societal perspective, including both direct and indirect costs. The study was an incidence-based cost-of-illness study based on national registries covering the entire population of Denmark. We identified all patients with a first-time hospital diagnosis of atrial fibrillation between 2001 and 2012. For every atrial fibrillation patient, we identified three age- and sex-matched controls from the general population. Both the total and the attributable costs of atrial fibrillation were estimated based on individual level information on hospital care (in- and out-patient contacts), primary sector care, use of prescription drugs and productivity loss. Average 3-year societal costs per patient attributable to atrial fibrillation were estimated to be €20,403-26,544 during the study period. The costs were highest during the first year after diagnosis of atrial fibrillation. Admission costs constituted the largest cost component, whereas primary sector costs and medicine costs only constituted minor components. The attributable costs were more than two-fold higher among patients experiencing a stroke. The total 3-year cost attributable to atrial fibrillation in Denmark was estimated to be €219-295 million. The societal costs attributable to atrial fibrillation are significant. Reducing the need for hospitalizations, in particular from stroke, is a key factor in controlling the costs.

  7. Cross-seeding of fibrils from two types of insulin induces new amyloid strains.

    Science.gov (United States)

    Surmacz-Chwedoruk, Weronika; Nieznańska, Hanna; Wójcik, Sławomir; Dzwolak, Wojciech

    2012-11-27

    The irreversibility and autocatalytic character of amyloidogenesis and the polymorphism of amyloid fibrils underlie the phenomenon of self-propagating strains, wherein the mother seed, rather than the seeding environment, determines the properties of daughter fibrils. Here we study the formation of amyloid fibrils from bovine insulin and the recombinant Lys(B31)-Arg(B32) human insulin analog. The two polypeptides are similar enough to cross-seed but, upon spontaneous aggregation, form amyloid fibrils with distinct spectral features in the infrared amide I' band region. When bovine insulin is cross-seeded with the analog amyloid (and vice versa), the shape, absorption maximum, and even fine fingerprint features of the amide I' band are passed from the mother to daughter fibrils with a high degree of fidelity. Although the differences in primary structure between bovine insulin and the Lys(B31)-Arg(B32) analog of human insulin lie outside of the polypeptide's critical amyloidogenic regions, they affect the secondary structure of fibrils, possibly the formation of intermolecular salt bridges, and the susceptibility to dissection and denaturation with dimethyl sulfoxide (DMSO). All these phenotypic features of mother fibrils are imprinted in daughter amyloid upon cross-seeding. Analysis of noncooperative DMSO-induced denaturation of daughter fibrils suggests that the self-propagating polymorphism underlying the emergence of new amyloid strains is encoded on the level of secondary structure. Our findings have been discussed in the context of polymorphism of fibrils, amyloid strains, and possible implications for mechanisms of amyloidogenesis.

  8. Amyloid fibril formation at a uniformly sheared air/water interface

    Science.gov (United States)

    Posada, David; Hirsa, Amir

    2013-11-01

    Amyloid fibril formation is a process by which protein molecules in solution form nuclei and aggregate into fibrils. Amyloid fibrils have long been associated with several common diseases such as Parkinson's disease and Alzheimer's. More recently, fibril protein deposition has been implicated in uncommon disorders leading to the failure of various organs including the kidneys, heart, and liver. Fibrillization can also play a detrimental role in biotherapeutic production. Results from previous studies show that a hydrophobic interface, such air/water, can accelerate fibrillization. Studies also show that agitation accelerates fibrillization. When attempting to elucidate fundamental mechanisms of fibrillization and distinguish the effects of interfaces and flow, it can be helpful to experiment with uniformly sheared interfaces. A new Taylor-Couette device is introduced for in situ, real-time high resolution microscopy. With a sub-millimeter annular gap, surface tension acts as the channel floor, permitting a stable meniscus to be placed arbitrarily close to a microscope to study amyloid fibril formation over long periods.

  9. Adherence and Coagulation Assays in Dabigatran-treated Patients With Atrial Fibrillation

    Science.gov (United States)

    2017-09-12

    Atrial Fibrillation; Medication Adherence; Blood Coagulation Tests; Anticoagulants; Circulating, Hemorrhagic Disorder; Drug Effect; Drug Use; Drug Toxicity; Drug Intolerance; Blood Clot; Blood Coagulation Disorder; Laboratory Problem; Bleeding; Thrombosis

  10. Electrical load detection aparatus

    DEFF Research Database (Denmark)

    2010-01-01

    A load detection technique for a load comprising multiple frequency-dependant sub-loads comprises measuring a representation of the impedance characteristic of the load; providing stored representations of a multiplicity of impedance characteristics of the load; each one of the stored representat...

  11. Minimally invasive fibrillating heart surgery: a safe and effective approach for mitral valve and surgical ablation for atrial fibrillation.

    Science.gov (United States)

    Massimiano, Paul S; Yanagawa, Bobby; Henry, Linda; Holmes, Sari D; Pritchard, Graciela; Ad, Niv

    2013-08-01

    Minimally invasive (MI) approaches to mitral valve surgery (MVS) and surgical ablation for atrial fibrillation (AF) are now performed routinely, and avoidance of aortic manipulation and cardioplegic arrest may further simplify the procedure. We present our experience with MI fibrillatory cardiac operations without aortic cross-clamping for MVS and AF ablation. Between January 2007 and August 2012, 292 consecutive patients underwent MVS (n = 177), surgical ablation (n = 81), or both (n= 34), with fibrillating heart through a right minithoracotomy. Baseline characteristics, perioperative outcomes, and long-term survival were evaluated. The mean age was 56.8 years (range, 20-83 years). Reoperations were performed in 25 patients (9%). The overall MV repair rate was 93.4% (198/211), including 13.1% (26/198) with anterior leaflet repair. Repair was performed in 100% of patients with myxomatous MV disease. Of isolated posterior mitral valve repairs, 60.5% underwent repair with neochords (W.L. Gore and Associates, Flagstaff, AZ), and 29.7% underwent triangular resection. There was 1 operative mortality (0.3%), no intraoperative conversions to sternotomy, 4 reoperations (1.4%), 1 stroke (0.3%), and 1 transient ischemic attack (0.3%). The 12-month return to sinus rhythm was 93%, and sinus rhythm without class I and class III antiarrhythmic medication was 85%. One- and 2-year cumulative survival was 98.5% and 97.8%, respectively. At mean follow-up of 27.3 months, our outcomes compared favorably with the 2011 Society of Thoracic Surgeons (STS) nationally reported outcomes. We demonstrated that low operative mortality and low stroke rate with MI fibrillating cardiac operations without cross-clamping allows for MVS and AF ablation. Our results suggest that the MI fibrillating heart approach is safe and effective. Copyright © 2013 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

  12. Familial clustering of atrial fibrillation and comparative longitudinal outcomes of familial and non-familial atrial fibrillation

    DEFF Research Database (Denmark)

    Gundlund, Anna; Olesen, Jonas B.; Peterson, Eric D.

    2017-01-01

    Several studies have suggested that family history of atrial fibrillation (AF) is an important risk factor for AF, with several specific genetic regions now implicated through Genome Wide Association Studies. In addition, familial AF is associated with earlier age of onset and affects patients...... with fewer comorbid conditions than their non-familial counterparts. While those with familial AF have worse symptoms, all-cause mortality and risk of thromboembolic complications are similar among familial and non-familial AF patients....

  13. Drivers of Tuberculosis Transmission.

    Science.gov (United States)

    Mathema, Barun; Andrews, Jason R; Cohen, Ted; Borgdorff, Martien W; Behr, Marcel; Glynn, Judith R; Rustomjee, Roxana; Silk, Benjamin J; Wood, Robin

    2017-11-03

    Measuring tuberculosis transmission is exceedingly difficult, given the remarkable variability in the timing of clinical disease after Mycobacterium tuberculosis infection; incident disease can result from either a recent (ie, weeks to months) or a remote (ie, several years to decades) infection event. Although we cannot identify with certainty the timing and location of tuberculosis transmission for individuals, approaches for estimating the individual probability of recent transmission and for estimating the fraction of tuberculosis cases due to recent transmission in populations have been developed. Data used to estimate the probable burden of recent transmission include tuberculosis case notifications in young children and trends in tuberculin skin test and interferon γ-release assays. More recently, M. tuberculosis whole-genome sequencing has been used to estimate population levels of recent transmission, identify the distribution of specific strains within communities, and decipher chains of transmission among culture-positive tuberculosis cases. The factors that drive the transmission of tuberculosis in communities depend on the burden of prevalent tuberculosis; the ways in which individuals live, work, and interact (eg, congregate settings); and the capacity of healthcare and public health systems to identify and effectively treat individuals with infectious forms of tuberculosis. Here we provide an overview of these factors, describe tools for measurement of ongoing transmission, and highlight knowledge gaps that must be addressed. © The Author 2017. Published by Oxford University Press for the Infectious Diseases Society of America.

  14. Predicting Major Bleeding in Ischemic Stroke Patients With Atrial Fibrillation.

    Science.gov (United States)

    Hilkens, Nina A; Algra, Ale; Greving, Jacoba P

    2017-11-01

    Performance of risk scores for major bleeding in patients with atrial fibrillation and a previous transient ischemic attack or ischemic stroke is not well established. We aimed to validate risk scores for major bleeding in patients with atrial fibrillation treated with oral anticoagulants after cerebral ischemia and explore the net benefit of oral anticoagulants among bleeding risk categories. We analyzed 3623 patients with a history of transient ischemic attack or stroke included in the RE-LY trial (Randomized Evaluation of Long-Term Anticoagulation Therapy). We assessed performance of HEMORR 2 HAGES (hepatic or renal disease, ethanol abuse, malignancy, older age, reduced platelet count or function, hypertension [uncontrolled], anemia, genetic factors, excessive fall risk, and stroke), Shireman, HAS-BLED (hypertension, abnormal renal/liver function, stroke, bleeding history or predisposition, labile international normalized ratio, elderly, drugs/alcohol concomitantly), ATRIA (Anticoagulation and Risk Factors in Atrial Fibrillation), and ORBIT scores (older age, reduced haemoglobin/haematocrit/history of anaemia, bleeding history, insufficient kidney function, and treatment with antiplatelet) with C statistics and calibration plots. Net benefit of oral anticoagulants was explored by comparing risk reduction in ischemic stroke with risk increase in major bleedings on warfarin. During 6922 person-years of follow-up, 266 patients experienced a major bleed (3.8 per 100 person-years). C statistics ranged from 0.62 (Shireman) to 0.67 (ATRIA). Calibration was poor for ATRIA and moderate for other models. The reduction in recurrent ischemic strokes on warfarin was larger than the increase in major bleeding risk, irrespective of bleeding risk category. Performance of prediction models for major bleeding in patients with cerebral ischemia and atrial fibrillation is modest but comparable with performance in patients with only atrial fibrillation. Bleeding risk scores cannot

  15. New Technologies in the Electricity Transmission

    International Nuclear Information System (INIS)

    Tonkovic, Z.

    2006-01-01

    In the report are presented main features of gas-insulated lines (GIL), as new technology solution in electricity transmission system. Despite currently high price of the GIL technology in comparison with conventional electro energy systems, mentioned is utilization of the technology in systems of a long cables and heavy loaded lines. Moreover, there is suggestion for the GIL usage in Republic of Croatia as well within multiuser projects in terms of cost reduction (project of gas network development in Dalmatia).(author)

  16. Distribution load estimation (DLE)

    Energy Technology Data Exchange (ETDEWEB)

    Seppaelae, A.; Lehtonen, M. [VTT Energy, Espoo (Finland)

    1998-08-01

    The load research has produced customer class load models to convert the customers` annual energy consumption to hourly load values. The reliability of load models applied from a nation-wide sample is limited in any specific network because many local circumstances are different from utility to utility and time to time. Therefore there is a need to find improvements to the load models or, in general, improvements to the load estimates. In Distribution Load Estimation (DLE) the measurements from the network are utilized to improve the customer class load models. The results of DLE will be new load models that better correspond to the loading of the distribution network but are still close to the original load models obtained by load research. The principal data flow of DLE is presented

  17. Atlas transmission line/transition design and fabrication status

    CERN Document Server

    Ballard, E O; Davis, H A; Elizondo, J M; Gribble, R F; Nielsen, K E; Parker, G V; Ricketts, R L; Valdez, G A

    1999-01-01

    Atlas is a pulsed-power facility under development at Los Alamos National Laboratory to drive high-energy density experiments. Design has been completed for this new generation pulsed-power machine consisting of an azimuthal array of 24, 240-kV Marx modules and transmission lines supplying current to the load region at the machine center. The transmission line consists of a cable header, load protection switch, and tri-plate assembly interfacing to the center transition section. The cable header interface to the Marx module provides a mechanism to remove the Marx module for maintenance without removing other components of the transmission line. The load protection switch provides a mechanism for protecting the load during charging of the Marx in the event of a pre-fire condition. The aluminum tri-plate is a low-inductance transmission line that carries radial current flow from the Marx energy storage system at the machine periphery toward the load. All transmission line components are oil insulated except the...

  18. Load frequency control of an asynchronous restructured power ...

    African Journals Online (AJOL)

    user

    This paper presents the analysis of load frequency control (LFC) of a two-area restructured power system interconnected via parallel ac/dc ... Keywords: Asynchronous tie-lines; Restructured power system; HVDC transmission links; Load frequency control; Fuzzy Logic ..... Automation, and Systems, Vol.4, No.2, pp.155-164.

  19. Clinical Differences between Subtypes of Atrial Fibrillation and Flutter: Cross-Sectional Registry of 407 Patients

    Directory of Open Access Journals (Sweden)

    Eduardo Dytz Almeida

    2015-01-01

    Full Text Available Introduction: Atrial fibrillation and atrial flutter account for one third of hospitalizations due to arrhythmias, determining great social and economic impacts. In Brazil, data on hospital care of these patients is scarce. Objective: To investigate the arrhythmia subtype of atrial fibrillation and flutter patients in the emergency setting and compare the clinical profile, thromboembolic risk and anticoagulants use. Methods: Cross-sectional retrospective study, with data collection from medical records of every patient treated for atrial fibrillation and flutter in the emergency department of Instituto de Cardiologia do Rio Grande do Sul during the first trimester of 2012. Results: We included 407 patients (356 had atrial fibrillation and 51 had flutter. Patients with paroxysmal atrial fibrillation were in average 5 years younger than those with persistent atrial fibrillation. Compared to paroxysmal atrial fibrillation patients, those with persistent atrial fibrillation and flutter had larger atrial diameter (48.6 ± 7.2 vs. 47.2 ± 6.2 vs. 42.3 ± 6.4; p < 0.01 and lower left ventricular ejection fraction (66.8 ± 11 vs. 53.9 ± 17 vs. 57.4 ± 16; p < 0.01. The prevalence of stroke and heart failure was higher in persistent atrial fibrillation and flutter patients. Those with paroxysmal atrial fibrillation and flutter had higher prevalence of CHADS2 score of zero when compared to those with persistent atrial fibrillation (27.8% vs. 18% vs. 4.9%; p < 0.01. The prevalence of anticoagulation in patients with CHA2DS2-Vasc ≤ 2 was 40%. Conclusions: The population in our registry was similar in its comorbidities and demographic profile to those of North American and European registries. Despite the high thromboembolic risk, the use of anticoagulants was low, revealing difficulties for incorporating guideline recommendations. Public health strategies should be adopted in order to improve these rates.

  20. Role of sequence and structural polymorphism on the mechanical properties of amyloid fibrils.

    Directory of Open Access Journals (Sweden)

    Gwonchan Yoon

    Full Text Available Amyloid fibrils playing a critical role in disease expression, have recently been found to exhibit the excellent mechanical properties such as elastic modulus in the order of 10 GPa, which is comparable to that of other mechanical proteins such as microtubule, actin filament, and spider silk. These remarkable mechanical properties of amyloid fibrils are correlated with their functional role in disease expression. This suggests the importance in understanding how these excellent mechanical properties are originated through self-assembly process that may depend on the amino acid sequence. However, the sequence-structure-property relationship of amyloid fibrils has not been fully understood yet. In this work, we characterize the mechanical properties of human islet amyloid polypeptide (hIAPP fibrils with respect to their molecular structures as well as their amino acid sequence by using all-atom explicit water molecular dynamics (MD simulation. The simulation result suggests that the remarkable bending rigidity of amyloid fibrils can be achieved through a specific self-aggregation pattern such as antiparallel stacking of β strands (peptide chain. Moreover, we have shown that a single point mutation of hIAPP chain constituting a hIAPP fibril significantly affects the thermodynamic stability of hIAPP fibril formed by parallel stacking of peptide chain, and that a single point mutation results in a significant change in the bending rigidity of hIAPP fibrils formed by antiparallel stacking of β strands. This clearly elucidates the role of amino acid sequence on not only the equilibrium conformations of amyloid fibrils but also their mechanical properties. Our study sheds light on sequence-structure-property relationships of amyloid fibrils, which suggests that the mechanical properties of amyloid fibrils are encoded in their sequence-dependent molecular architecture.

  1. Vitamin B12 Inhibits Tau Fibrillization via Binding to Cysteine Residues of Tau.

    Science.gov (United States)

    Rafiee, Saharnaz; Asadollahi, Kazem; Riazi, Gholamhossein; Ahmadian, Shahin; Saboury, Ali Akbar

    2017-12-20

    Two mechanisms underlie the inhibitory/acceleratory action of chemical compounds on tau aggregation including the regulation of cellular kinases and phosphatases activity and direct binding to tau protein. Vitamin B12 is one of the tau polymerization inhibitors, and its deficiency is linked to inactivation of protein phosphatase 2A and subsequently hyperphosphorylation and aggregation of tau protein. Regarding the structure and function of vitamin B12 and tau protein, we assumed that vitamin B12 is also able to directly bind to tau protein. Hence, we investigated the interaction of vitamin B12 with tau protein in vitro using fluorometry and circular dichrosim. Interaction studies was followed by investigation into the effect of vitamin B12 on tau aggregation using ThT fluorescence, circular dichroism, transmission electron microscopy, and SDS-PAGE. The results indicated that vitamin B12 interacts with tau protein and prevents fibrillization of tau protein. Blocking the cysteine residues of tau confirmed the cysteine-mediated binding of vitamin B12 to tau and showed that binding to cysteine is essential for inhibitory effect of vitamin B12 on tau aggregation. SDS-PAGE analysis indicated that vitamin B12 inhibits tau aggregation and that tau oligomers formed in the presence of vitamin B12 are mostly SDS-soluble. We propose that direct binding of vitamin B12 is another mechanism underlying the inhibitory role of vitamin B12 on tau aggregation and neurodegeneration.

  2. Pitx2, an atrial fibrillation predisposition gene, directly regulates ion transport and intercalated disc genes.

    Science.gov (United States)

    Tao, Ye; Zhang, Min; Li, Lele; Bai, Yan; Zhou, Yuefang; Moon, Anne M; Kaminski, Henry J; Martin, James F

    2014-02-01

    Pitx2 is the homeobox gene located in proximity to the human 4q25 familial atrial fibrillation (AF) locus. When deleted in the mouse germline, Pitx2 haploinsufficiency predisposes to pacing-induced AF, indicating that reduced Pitx2 promotes an arrhythmogenic substrate. Previous work focused on Pitx2 developmental functions that predispose to AF. Although Pitx2 is expressed in postnatal left atrium, it is unknown whether Pitx2 has distinct postnatal and developmental functions. To investigate Pitx2 postnatal function, we conditionally inactivated Pitx2 in the postnatal atrium while leaving its developmental function intact. Unstressed adult Pitx2 homozygous mutant mice display variable R-R interval with diminished P-wave amplitude characteristic of sinus node dysfunction, an AF risk factor in human patients. An integrated genomics approach in the adult heart revealed Pitx2 target genes encoding cell junction proteins, ion channels, and critical transcriptional regulators. Importantly, many Pitx2 target genes have been implicated in human AF by genome-wide association studies. Immunofluorescence and transmission electron microscopy studies in adult Pitx2 mutant mice revealed structural remodeling of the intercalated disc characteristic of human patients with AF. Our findings, revealing that Pitx2 has genetically separable postnatal and developmental functions, unveil direct Pitx2 target genes that include channel and calcium handling genes, as well as genes that stabilize the intercalated disc in postnatal atrium.

  3. New implantable therapeutic device for the control of an atrial fibrillation attack using the Peltier element.

    Science.gov (United States)

    Yambe, Tomoyuki; Sumiyoshi, Taketada; Koga, Chihiro; Shiraishi, Yasuyuki; Miura, Hidekazu; Sugita, Norihiro; Tanaka, Akira; Yoshizawa, Makoto

    2012-01-01

    For the development of the new therapeutic device for the atrial fibrillation, implantable cooling device using Peltier element was developed in this study. An implantable cooling device had been consisted from Peltier element with transcutaneous energy transmission system (TETS). 1st coil can be contacted from outside of the body, when the patients will feel palpitation. Electrical current will be induced to the implanted 2nd coil. Peltier element will able to cool the surface of the atrium. For the confirmation of the effect of the cooling device, trial manufacture model was developed. Animal experiments using six healthy adult goats after animal ethical committee allowance was carried out. Fourth intercostals space had been opened after anesthesia inhalation, and various sensors had been inserted. AF was induced by the electrical current with battery. As the results, AF had been recovered to the normal sinus rhythm after cooling in all six goats. So, this cooling system for the control of AF showed evident effect in these experiments. Smaller size cooling device has been under development aiming at totally implantable type. Catheter type cooling device for the insertion by the use of fiber-scope type is now under planning for the clinical application. This new type device may be able to become good news for the patients with uncontrollable AF.

  4. Stabilization of Collagen Fibrils by Gelatin Addition: A Study of Collagen/Gelatin Dense Phases.

    Science.gov (United States)

    Portier, François; Teulon, Claire; Nowacka-Perrin, Agnieszka; Guenneau, Flavien; Schanne-Klein, Marie-Claire; Mosser, Gervaise

    2017-11-14

    Collagen and its denatured form, gelatin, are biopolymers of fundamental interest in numerous fields ranging from living tissues to biomaterials, food, and cosmetics. This study aims at characterizing mixtures of those biopolymers at high concentrations (up to 100 mg·mL -1 ) at which collagen has mesogenic properties. We use a structural approach combining polarization-resolved multiphoton microscopy, polarized light microscopy, magnetic resonance imaging, and transmission electron microscopy to analyze gelatin and collagen/gelatin dense phases in their sol and gel states from the macroscopic to the microscopic scale. We first report the formation of a lyotropic crystal phase of gelatin A and show that gelatin must structure itself in particles to become mesogenic. We demonstrate that mixtures of collagen and gelatin phase segregate, preserving the setting of the pure collagen mesophase at a gelatin ratio of up to 20% and generating a biphasic fractal sample at all tested ratios. Moreover, differential scanning calorimetric analysis shows that each protein separates into two populations. Both populations of gelatins are stabilized by the presence of collagen, whereas only one population of collagen molecules is stabilized by the presence of gelatin, most probably those at the interface of the fibrillated microdomains and of the gelatin phase. Although further studies are needed to fully understand the involved mechanism, these new data should have a direct impact on the bioengineering of those two biopolymers.

  5. Cultural Transmission of Civicness

    DEFF Research Database (Denmark)

    Ljunge, Jan Martin

    2012-01-01

    This paper estimates the intergeneration transmission of civicness by studying second generation immigrants in 29 European countries with ancestry in 83 nations. There is significant transmission of civicness both on the mother’s and the father’s side. The estimates are quantitatively significant...

  6. Cultural Transmission of Civicness

    DEFF Research Database (Denmark)

    Ljunge, Jan Martin

    This paper estimates the intergeneration transmission of civicness by studying second generation immigrants in 29 European countries with ancestry in 83 nations. There is significant transmission of civicness both on the mother’s and the father’s side. The estimates are quantitatively significant...

  7. The changing face of glucagon fibrillation: Structural polymorphism and conformational imprinting

    DEFF Research Database (Denmark)

    Pedersen, J.S.; Dikov, D.; Flink, J.L.

    2006-01-01

    concentration) appear less thermostable than those formed under more challenging conditions (high temperatures, low glucagon or low salt concentrations). Properties of preformed fibrils used for seeding are inherited in a prion-like manner. Thus, we conclude that the structure of fibrils formed by glucagon...

  8. Influence of Aluminium and EGCG on Fibrillation and Aggregation of Human Islet Amyloid Polypeptide

    Directory of Open Access Journals (Sweden)

    Zhi-Xue Xu

    2016-01-01

    Full Text Available The abnormal fibrillation of human islet amyloid polypeptide (hIAPP has been implicated in the development of type II diabetes. Aluminum is known to trigger the structural transformation of many amyloid proteins and induce the formation of toxic aggregate species. The (−-epigallocatechin gallate (EGCG is considered capable of binding both metal ions and amyloid proteins with inhibitory effect on the fibrillation of amyloid proteins. However, the effect of Al(III/EGCG complex on hIAPP fibrillation is unclear. In the present work, we sought to view insight into the structures and properties of Al(III and EGCG complex by using spectroscopic experiments and quantum chemical calculations and also investigated the influence of Al(III and EGCG on hIAPP fibrillation and aggregation as well as their combined interference on this process. Our studies demonstrated that Al(III could promote fibrillation and aggregation of hIAPP, while EGCG could inhibit the fibrillation of hIAPP and lead to the formation of hIAPP amorphous aggregates instead of the ordered fibrils. Furthermore, we proved that the Al(III/EGCG complex in molar ratio of 1 : 1 as Al(EGCG(H2O2 could inhibit the hIAPP fibrillation more effectively than EGCG alone. The results provide the invaluable reference for the new drug development to treat type II diabetes.

  9. Heat-induced whey protein isolate fibrils: Conversion, hydrolysis, and disulphide bond formation

    NARCIS (Netherlands)

    Bolder, S.G.; Vasbinder, A.; Sagis, L.M.C.; Linden, van der E.

    2007-01-01

    Fibril formation of individual pure whey proteins and whey protein isolate (WPI) was studied. The heat-induced conversion of WPI monomers into fibrils at pH 2 and low ionic strength increased with heating time and protein concentration. Previous studies, using a precipitation method, size-exclusion

  10. Impact of atrial fibrillation on mortality in patients with chronic heart failure

    NARCIS (Netherlands)

    van den Berg, MP; van Gelder, IC; van Veldhuisen, DJ

    2002-01-01

    Chronic heart failure and atrial fibrillation often occur together. The aim of the study is to review the available literature on the impact of atrial fibrillation on mortality in patients with heart failure. Using MEDLINE six full papers were identified. In the studies with severe heart failure

  11. Amyloid Fibril-Induced Structural and Spectral Modifications in the Thioflavin-T Optical Probe

    DEFF Research Database (Denmark)

    Murugan, N. Arul; Olsen, Jógvan Magnus Haugaard; Kongsted, Jacob

    2013-01-01

    Motivated by future possibilities to design target molecules for fibrils with diagnostic or therapeutic capability related to amyloidosis diseases, we investigate in this work the dielectric nature of amyloid fibril microenvironments in different binding sites using an optical probe, thioflavin-T...

  12. Assembly of α-synuclein fibrils in nanoscale studied by peptide truncation and AFM

    International Nuclear Information System (INIS)

    Zhang Feng; Lin Xiaojing; Ji Lina; Du Haining; Tang Lin; He Jianhua; Hu Jun; Hu Hongyu

    2008-01-01

    α-Synuclein (α-Syn) fibrils are the major component of Lewy bodies that are closely associated with the pathogenesis of Parkinson's disease, but the mechanism for the fibril assembly remains poorly understood. Here we report using a combination of peptide truncation and atomic force microscopy (AFM) to elucidate the self-assembly and morphology of the α-Syn fibrils. The results show that protease K significantly slims the fibrils from the mean height of ∼6.6 to ∼4.7 nm, whereas chaotropic denaturant urea completely breaks down the fibrils into small particles. The in situ enzymatic digestion also results in thinning of the fibrils, giving rise to some nicks on the fibrils. Moreover, N- or C-terminally truncated α-Syn fragments assemble into thinner filaments with the heights depending on the peptide lengths. A nine-residue peptide corresponding to the homologous GAV-motif sequence can form very thin (∼2.2 nm) but long (>1 μm) filaments. Thus, the central sequence of α-Syn forms a fibrillar core by cross-β-structure that is flanked by two flexible termini, and the orientation of the fibril growth is perpendicular to the β-sheet structures

  13. J-shaped association between QTc interval duration and the risk of atrial fibrillation

    DEFF Research Database (Denmark)

    Nielsen, Jonas Bille; Graff, Claus; Pietersen, Adrian

    2013-01-01

    The aim of this study was to investigate whether the heart rate-corrected QT (QTc) interval on the electrocardiogram (ECG) is associated with the onset of atrial fibrillation (AF).......The aim of this study was to investigate whether the heart rate-corrected QT (QTc) interval on the electrocardiogram (ECG) is associated with the onset of atrial fibrillation (AF)....

  14. Sodium dodecyl sulphate (SDS) induced changes in propensity and kinetics of α-lactalbumin fibrillation.

    Science.gov (United States)

    Kumar, E Kiran; Qumar, Shamsul; Prabhu, N Prakash

    2015-11-01

    Understanding surfactants induced changes on protein folding, aggregation, and fibrillation has a lot of implications in their laboratory and industrial applications. The effect of an anionic surfactant, sodium dodecyl sulphate (SDS), on fibrillation of an acidic protein α-lactalbumin (α-LA) at neutral pH condition was investigated. SDS at lower concentrations increased the lag time by nearly two-fold whereas the fibril elongation rate was not significantly altered. At the concentrations above 0.2mM, SDS lengthened the lag time by many-fold (∼60), but fibril elongation was accelerated by 3-6 fold. At the concentrations above 2mM, SDS inhibited α-LA fibrillation and led it to the formation of amorphous aggregates. These results were compared with the effect of SDS on the fibrillation of lysozyme, a basic protein. Though fibril inhibition was observed on both the proteins at the micellar concentrations of SDS, there were differences in the effect on lag time and elongation rate at the lower concentrations of SDS. This suggests that the inhibition of protein fibrillation by SDS-micelles might be a common mechanism irrespective of the surface charges on protein. Copyright © 2015 Elsevier B.V. All rights reserved.

  15. Temporal changes in patient characteristics and prior pharmacotherapy in patients undergoing radiofrequency ablation of atrial fibrillation

    DEFF Research Database (Denmark)

    Karasoy, Deniz; Gislason, Gunnar Hilmar; Hansen, Jim

    2013-01-01

    Trends in patient selection and pharmacotherapy before radiofrequency ablation (RFA) of atrial fibrillation are not well studied. We examined temporal trends in RFA utilization on a nationwide scale in Denmark.......Trends in patient selection and pharmacotherapy before radiofrequency ablation (RFA) of atrial fibrillation are not well studied. We examined temporal trends in RFA utilization on a nationwide scale in Denmark....

  16. The spectrum of thyroid disease and risk of new onset atrial fibrillation

    DEFF Research Database (Denmark)

    Selmer, Christian; Olesen, Jonas Bjerring; Hansen, Morten Lock

    2012-01-01

    To examine the risk of atrial fibrillation in relation to the whole spectrum of thyroid function in a large cohort of patients.......To examine the risk of atrial fibrillation in relation to the whole spectrum of thyroid function in a large cohort of patients....

  17. Essential Oils May Lead α-Synuclein towards Toxic Fibrils Formation

    Directory of Open Access Journals (Sweden)

    Dina Morshedi

    2016-01-01

    Full Text Available α-Synuclein (α-Syn fibrillation links with Parkinson’s disease (PD and several related syndromes. It is believed that exposure to the factors which promote fibrillation may induce and progress such neurodegenerative diseases (NDs. Herein, the effects of some wildly used essential oils including Myrtus communis (M. communis on α-Syn fibrillation were examined. M. communis particularly increased α-Syn fibrillation in a concentration dependent manner. Given that applications of M. communis are very extensive in Asian societies, especially Zoroastrians, this study was extended towards its role on α-Syn fibrillation/cytotoxicity. By using a unilamellar vesicle, it was shown that the aggregated species with tendency to perturb membrane were increased in the presence of M. communis. In this regard, the cytotoxicity of α-Syn on SH-SH5Y cells was also increased significantly. Inappropriately, the effects of fibrillation inhibitors, baicalein and cuminaldehyde, were modulated in the presence of M. communis. However, major components of M. communis did not induce fibrillation and also the effect of M. communis was limited on other fibrinogenic proteins. Assuming that essential oils have the ability to pass through the blood brain barrier (BBB along with the popular attention on aromatherapy for the incurable ND, these findings suggest an implementation of fibrillation tests for essential oils.

  18. Polymorphism, metastable species and interconversion: the many states of glucagon fibrils

    DEFF Research Database (Denmark)

    Ghodke, Shirin D; Jensen, Grethe Vestergaard; Svane, Anna Sigrid P.

    2014-01-01

    The natively unfolded peptide hormone glucagon forms fibrillar structures with amyloid properties. Here, we summarize past advances in glucagon fibrillation and combine them with recent new unpublished data to provide some more general conclusions on how glucagon fibrillation adapts to different...

  19. Use of Vitamins K antagonists in non-valvular atrial fibrillation ...

    African Journals Online (AJOL)

    Introduction: atrial fibrillation is the commonest cardiac rythm disorder. Thromboembolic accidents are common complications that should be prevented by anticoagulant treatment. The aim of our study is to assess the use of vitamins K antagonists in the prevention of thromboembolic risk in atrial fibrillation. Methods: it was a ...

  20. Master and slave relationship between two types of self-propagating insulin amyloid fibrils.

    Science.gov (United States)

    Surmacz-Chwedoruk, Weronika; Babenko, Viktoria; Dzwolak, Wojciech

    2014-11-26

    Cross-seeding of fibrils of bovine insulin (BI) and Lys(B31)-Arg(B32) human insulin analog (KR) induces self-propagating amyloid variants with infrared features inherited from mother seeds. Here we report that when native insulin (BI or KR) is simultaneously seeded with mixture of equal amounts of both templates (i.e., of separately grown fibrils of BI and KR), the phenotype of resulting daughter fibrils is as in the case of the purely homologous seeding: heterologous cotemplates accelerate the fibrillation but do not determine infrared traits of the daughter amyloid. This implies that fibrillation-promoting and structure-imprinting properties of heterologous seeds become uncoupled in the presence of homologous seeds. We argue that explanation of such behavior requires that insulin molecules partly transformed through interactions with heterologous fibrils are subsequently recruited by homologous seeds. The selection bias toward homologous daughter amyloid is exceptional: more than 200-fold excess of heterologous seed is required to imprint its structural phenotype upon mixed seeding. Our study captures a snapshot of elusive docking interactions in statu nascendi of elongation of amyloid fibril and suggests that different types of seeds may collaborate in sequential processing of soluble protein into fibrils.