WorldWideScience

Sample records for capillary-alveolar macromolecular leakage

  1. Curcumin suppresses gastric NF-κB activation and macromolecular leakage in Helicobacter pylori-infected rats

    Institute of Scientific and Technical Information of China (English)

    Kawiya; Sintara; Duangporn; Thong-Ngam; Suthiluk; Patumraj; Naruemon; Klaikeaw; Tanittha; Chatsuwan

    2010-01-01

    AIM:To investigate whether curcumin could attenuate nuclear factor(NF)-κB p65 expression and macromolecular leakage in the gastric mucosa of Helicobacter pylori(H.pylori)-infected rats.METHODS:Twenty-five male Sprague-Dawley rats were equally divided into five groups:control rats(Control),control rats supplemented with 600 mg/kg curcumin,H.pylori-infected rats(Hp),H.pylori-infected rats supplemented with 200 mg/kg curcumin(Hp + curIn H.pylori-infected groups,rats were inoculated with H.pylori suspension twi...

  2. Effects of babassu nut oil on ischemia/reperfusion-induced leukocyte adhesion and macromolecular leakage in the microcirculation: Observation in the hamster cheek pouch

    Directory of Open Access Journals (Sweden)

    Barbosa Maria do

    2012-11-01

    Full Text Available Abstract Background The babassu palm tree is native to Brazil and is most densely distributed in the Cocais region of the state of Maranhão, in northeastern Brazil. In addition to the industrial use of refined babassu oil, the milk, the unrefined oil and the nuts in natura are used by families from several communities of African descendants as one of the principal sources of food energy. The objective of this study was to evaluate the effects of babassu oil on microvascular permeability and leukocyte-endothelial interactions induced by ischemia/reperfusion using the hamster cheek pouch microcirculation as experimental model. Methods Twice a day for 14 days, male hamsters received unrefined babassu oil (0.02 ml/dose [BO-2 group], 0.06 ml/dose [BO-6 group], 0.18 ml/dose [BO-18 group] or mineral oil (0.18 ml/dose [MO group]. Observations were made in the cheek pouch and macromolecular permeability increase induced by ischemia/reperfusion (I/R or topical application of histamine, as well as leukocyte-endothelial interaction after I/R were evaluated. Results The mean value of I/R-induced microvascular leakage, determined during reperfusion, was significantly lower in the BO-6 and BO-18 groups than in the MO one (P Conclusions Our findings suggest that unrefined babassu oil reduced microvascular leakage and protected against histamine-induced effects in postcapillary venules and highlights that these almost unexploited nut and its oil might be secure sources of food energy.

  3. Macromolecular Prodrugs of Ribavirin

    DEFF Research Database (Denmark)

    Riber, Camilla Frich; Hinton, Tracey M; Gajda, Paulina

    2017-01-01

    The requirement for new antiviral therapeutics is an ever present need. Particularly lacking are broad spectrum antivirals that have low toxicity. We develop such agents based on macromolecular prodrugs whereby both the polymer chain and the drug released from the polymer upon cell entry have ant...

  4. Macromolecular Crystallization in Microgravity

    Science.gov (United States)

    Snell, Edward H.; Helliwell, John R.

    2004-01-01

    The key concepts that attracted crystal growers, macromolecular or solid state, to microgravity research is that density difference fluid flows and sedimentation of the growing crystals are greatly reduced. Thus, defects and flaws in the crystals can be reduced, even eliminated, and crystal volume can be increased. Macromolecular crystallography differs from the field of crystalline semiconductors. For the latter, crystals are harnessed for their electrical behaviors. A crystal of a biological macromolecule is used instead for diffraction experiments (X-ray or neutron) to determine the three-dimensional structure of the macromolecule. The better the internal order of the crystal of a biological macromolecule then the more molecular structure detail that can be extracted. This structural information that enables an understanding of how the molecule functions. This knowledge is changing the biological and chemical sciences with major potential in understanding disease pathologies. Macromolecular structural crystallography in general is a remarkable field where physics, biology, chemistry, and mathematics meet to enable insight to the basic fundamentals of life. In this review, we examine the use of microgravity as an environment to grow macromolecular crystals. We describe the crystallization procedures used on the ground, how the resulting crystals are studied and the knowledge obtained from those crystals. We address the features desired in an ordered crystal and the techniques used to evaluate those features in detail. We then introduce the microgravity environment, the techniques to access that environment, and the theory and evidence behind the use of microgravity for crystallization experiments. We describe how ground-based laboratory techniques have been adapted to microgravity flights and look at some of the methods used to analyze the resulting data. Several case studies illustrate the physical crystal quality improvements and the macromolecular structural

  5. Macromolecular crystallization in microgravity

    Energy Technology Data Exchange (ETDEWEB)

    Snell, Edward H [Biophysics Group, NASA Marshall Space Flight Center, Code XD42, Huntsville, AL 35812 (United States); Helliwell, John R [Department of Chemistry, The University of Manchester, Manchester, M13 9PL (United Kingdom)

    2005-04-01

    Density difference fluid flows and sedimentation of growing crystals are greatly reduced when crystallization takes place in a reduced gravity environment. In the case of macromolecular crystallography a crystal of a biological macromolecule is used for diffraction experiments (x-ray or neutron) so as to determine the three-dimensional structure of the macromolecule. The better the internal order of the crystal then the greater the molecular structure detail that can be extracted. It is this structural information that enables an understanding of how the molecule functions. This knowledge is changing the biological and chemical sciences, with major potential in understanding disease pathologies. In this review, we examine the use of microgravity as an environment to grow macromolecular crystals. We describe the crystallization procedures used on the ground, how the resulting crystals are studied and the knowledge obtained from those crystals. We address the features desired in an ordered crystal and the techniques used to evaluate those features in detail. We then introduce the microgravity environment, the techniques to access that environment and the theory and evidence behind the use of microgravity for crystallization experiments. We describe how ground-based laboratory techniques have been adapted to microgravity flights and look at some of the methods used to analyse the resulting data. Several case studies illustrate the physical crystal quality improvements and the macromolecular structural advances. Finally, limitations and alternatives to microgravity and future directions for this research are covered. Macromolecular structural crystallography in general is a remarkable field where physics, biology, chemistry and mathematics meet to enable insight to the fundamentals of life. As the reader will see, there is a great deal of physics involved when the microgravity environment is applied to crystallization, some of it known, and undoubtedly much yet to

  6. Microgravity and Macromolecular Crystallography

    Science.gov (United States)

    Kundrot, Craig E.; Judge, Russell A.; Pusey, Marc L.; Snell, Edward H.; Rose, M. Franklin (Technical Monitor)

    2000-01-01

    Macromolecular crystal growth has been seen as an ideal experiment to make use of the reduced acceleration environment provided by an orbiting spacecraft. The experiments are small, simply operated and have a high potential scientific and economic impact. In this review we examine the theoretical reasons why microgravity should be a beneficial environment for crystal growth and survey the history of experiments on the Space Shuttle Orbiter, on unmanned spacecraft, and on the Mir space station. Finally we outline the direction for optimizing the future use of orbiting platforms.

  7. Land-use Leakage

    Energy Technology Data Exchange (ETDEWEB)

    Calvin, Katherine V.; Edmonds, James A.; Clarke, Leon E.; Bond-Lamberty, Benjamin; Kim, Son H.; Wise, Marshall A.; Thomson, Allison M.; Kyle, G. Page

    2009-12-01

    Leakage occurs whenever actions to mitigate greenhouse gas emissions in one part of the world unleash countervailing forces elsewhere in the world so that reductions in global emissions are less than emissions mitigation in the mitigating region. While many researchers have examined the concept of industrial leakage, land-use policies can also result in leakage. We show that land-use leakage is potentially as large as or larger than industrial leakage. We identify two potential land-use leakage drivers, land-use policies and bioenergy. We distinguish between these two pathways and run numerical experiments for each. We also show that the land-use policy environment exerts a powerful influence on leakage and that under some policy designs leakage can be negative. International “offsets” are a potential mechanism to communicate emissions mitigation beyond the borders of emissions mitigating regions, but in a stabilization regime designed to limit radiative forcing to 3.7 2/m2, this also implies greater emissions mitigation commitments on the part of mitigating regions.

  8. Model for Electromagnetic Information Leakage

    OpenAIRE

    Mao Jian; Li Yongmei; Zhang Jiemin; Liu Jinming

    2013-01-01

    Electromagnetic leakage will happen in working information equipments; it could lead to information leakage. In order to discover the nature of information in electromagnetic leakage, this paper combined electromagnetic theory with information theory as an innovative research method. It outlines a systematic model of electromagnetic information leakage, which theoretically describes the process of information leakage, intercept and reproduction based on electromagnetic radiation, and ana...

  9. Predicting Leakage in Labyrinth Seals

    Science.gov (United States)

    Morrison, G. L.; Rhode, D. L.; Cogan, K. C.; Chi, D.; Demko, J.

    1985-01-01

    Analytical and empirical methods evaluated. 264-page report presents comprehensive information on leakage in labyrinth seals. Summarizes previous analyses of leakage, reviews leakage tests conducted by authors and evaluates various analytical and experimental methods of determining leakage and discusses leakage prediction techniques.

  10. Macromolecular architectures for organic photovoltaics.

    Science.gov (United States)

    Popere, Bhooshan C; Della Pelle, Andrea M; Poe, Ambata; Thayumanavan, S

    2012-03-28

    Research in the field of organic photovoltaics has gained considerable momentum in the last two decades owing to the need for developing low-cost and efficient energy harvesting systems. Elegant molecular architectures have been designed, synthesized and employed as active materials for photovoltaic devices thereby leading to a better molecular structure-device property relationship understanding. In this perspective, we outline new macromolecular scaffolds that have been designed within the purview of each of the three fundamental processes involving light harvesting, charge separation and charge transport.

  11. Data Mining of Macromolecular Structures.

    Science.gov (United States)

    van Beusekom, Bart; Perrakis, Anastassis; Joosten, Robbie P

    2016-01-01

    The use of macromolecular structures is widespread for a variety of applications, from teaching protein structure principles all the way to ligand optimization in drug development. Applying data mining techniques on these experimentally determined structures requires a highly uniform, standardized structural data source. The Protein Data Bank (PDB) has evolved over the years toward becoming the standard resource for macromolecular structures. However, the process selecting the data most suitable for specific applications is still very much based on personal preferences and understanding of the experimental techniques used to obtain these models. In this chapter, we will first explain the challenges with data standardization, annotation, and uniformity in the PDB entries determined by X-ray crystallography. We then discuss the specific effect that crystallographic data quality and model optimization methods have on structural models and how validation tools can be used to make informed choices. We also discuss specific advantages of using the PDB_REDO databank as a resource for structural data. Finally, we will provide guidelines on how to select the most suitable protein structure models for detailed analysis and how to select a set of structure models suitable for data mining.

  12. Emergent Property in Macromolecular Motion

    Institute of Scientific and Technical Information of China (English)

    吴嘉麟

    2003-01-01

    In this paper, the model of inverse cascade fractal super-blocks along one direction (in the positive or negative) in the 3-dimensional space is developed to describe the self-similar motion in macromolecular system. Microscopically the cohesive and dispersed states of the motion blocks are co-existent states with vastly different probability of occurrence.Experimental results and theoretical analysis show that the microscopic cohesive state energy and dispersed state energy of each motion block are respectively equal to the macroscopic glassy state energy kT8 and molten state energy kTm of the system. This singularity unveils topologically the nonintegrability, mathematically the anholonomy, and macroscopically the emergent property. This singularity also reveals that the glass, viscoelastic and melt states are three distinct emergent properties of macromolecular motion from a macroscopic viewpoint. The fractal concept of excluded volume is introduced to depict the random motion at various scales in the system. The Hausdorff dimensions of the excluded volune and the motion blocks are both found equal to 3/2.

  13. Model for Electromagnetic Information Leakage

    Directory of Open Access Journals (Sweden)

    Mao Jian

    2013-09-01

    Full Text Available Electromagnetic leakage will happen in working information equipments; it could lead to information leakage. In order to discover the nature of information in electromagnetic leakage, this paper combined electromagnetic theory with information theory as an innovative research method. It outlines a systematic model of electromagnetic information leakage, which theoretically describes the process of information leakage, intercept and reproduction based on electromagnetic radiation, and analyzes amount of leakage information with formulas.  

  14. Liver-targeting macromolecular MRI contrast agents

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Macromolecular ligands with liver-targeting group (pyridoxamine, PM) PHEA-DTPA-PM and PAEA-DTPA-PM were prepared by the incorporation of different amount of diethylenetriaminepentaacetic acid monopyridoxamine group (DTPA-PM) into poly-a, b-[N-(2-hydroxyethyl)-L- aspartamide] (PHEA) and poly-a, b-[N-(2-aminoethyl)-L-aspartamide] (PAEA). The macromolecular ligands thus obtained were further complexed with gadolinium chloride to give macromolecular MRI contrast agents with different Gd(Ⅲ) contents. These macromolecular ligands and their gadolinium complexes were characterized by 1H NMR, IR, UV and elementary analysis. Relaxivity studies showed that these polyaspartamide gadolinium complexes possess higher relaxation effectiveness than that of the clinically used Gd-DTPA. Magnetic resonance imaging of the liver in rats and experimental data of biodistribution in mice indicate that these macromolecular MRI contrast agents containing pyridoxamine exhibit liver-targeting property.

  15. Accidental Bowel Leakage

    Science.gov (United States)

    ... I do to help treat accidental bowel leakage? Kegel exercises strengthen the muscles that surround the openings ... bowels that may cause cramping, diarrhea, or constipation. Kegel Exercises: Pelvic muscle exercises that assist in bladder ...

  16. Automated data collection for macromolecular crystallography.

    Science.gov (United States)

    Winter, Graeme; McAuley, Katherine E

    2011-09-01

    An overview, together with some practical advice, is presented of the current status of the automation of macromolecular crystallography (MX) data collection, with a focus on MX beamlines at Diamond Light Source, UK.

  17. Zero leakage sealings

    Science.gov (United States)

    Kotesovec, Bernhard; Steinrück, Herbert

    2010-11-01

    The piston rod of a reciprocating compressor is sealed with elastic cylindrical sealing elements. Across the sealings the pressure drops from the operating pressure to the ambient pressure. The lubrication gap between the elastic sealing and reciprocating piston rod is studied with the aim to find conditions of a leakage free sealing. The flow in the lubrication gap and the elastic deformation of the sealing are determined simultaneously. The net-flow during one cycle of the reciprocating piston rod is calculated. It turns out that maintaining zero leakage is very sensible. Indeed the outbound flow during out-stroke has to be equal the inbound flow during the in-stroke. By prescribing a special shape of the undeformed sealing zero leakage can be attained - at least theoretically for certain operating conditions. It turns out that temperature dependent material data and a model for cavitation is necessary. The model, its numerical implementation and results will be discussed.

  18. Energy transfer in macromolecular arrays

    Science.gov (United States)

    Andrews, David L.; Jenkins, Robert D.

    2003-11-01

    Macromolecular systems comprised of many light-sensitive centres (the photosynthetic unit, dendrimers, and other highly symmetric multichromophore arrays) are important structures offering challenges to theoreticians and synthetic chemists alike. Here we outline novel photophysical interactions predicted and observed in such arrays. Using the tools of molecular quantum electrodynamics (QED) we present quantum amplitudes for a variety of higher-order resonance energy transfer (RET) schemes associated with well-known nonlinear optical effects such as two- and three-photon absorption. The initial analysis is extended to account for situations where the participant donor species are identical and exist in a highly symmetric environment, leading to the possible formation of excitons. It emerges from the QED theory that such excitons are closely associated with the higher-order RET processes. General results are interpreted by analyzing particular molecular architectures which offer interesting features such as rate enhancement or limitation and exciton pathway quenching. Applications in the areas of photosynthesis, molecular logic gates and low-intensity fluorescence energy transfer are predicted.

  19. Effects of macromolecular crowding on genetic networks.

    Science.gov (United States)

    Morelli, Marco J; Allen, Rosalind J; Wolde, Pieter Rein ten

    2011-12-21

    The intracellular environment is crowded with proteins, DNA, and other macromolecules. Under physiological conditions, macromolecular crowding can alter both molecular diffusion and the equilibria of bimolecular reactions and therefore is likely to have a significant effect on the function of biochemical networks. We propose a simple way to model the effects of macromolecular crowding on biochemical networks via an appropriate scaling of bimolecular association and dissociation rates. We use this approach, in combination with kinetic Monte Carlo simulations, to analyze the effects of crowding on a constitutively expressed gene, a repressed gene, and a model for the bacteriophage λ genetic switch, in the presence and absence of nonspecific binding of transcription factors to genomic DNA. Our results show that the effects of crowding are mainly caused by the shift of association-dissociation equilibria rather than the slowing down of protein diffusion, and that macromolecular crowding can have relevant and counterintuitive effects on biochemical network performance.

  20. Macromolecular mimicry of nucleic acid and protein

    DEFF Research Database (Denmark)

    Nautrup Pedersen, Gitte; Nyborg, Jens; Clark, Brian F

    1999-01-01

    of the concept of macromolecular mimicry. Macromolecular mimicry has further been proposed among initiation and release factors, thereby adding a new element to the description of protein synthesis in bacteria. Such mimicry has also been observed in other biological processes such as autoimmunity, DNA repair......Although proteins and nucleic acids consist of different chemical components, proteins can mimic structures and possibly also functions of nucleic acids. Recently, structural mimicry was observed between two elongation factors in bacterial protein biosynthesis leading to the introduction...

  1. Leakage resilient password systems

    CERN Document Server

    Li, Yingjiu; Deng, Robert H

    2015-01-01

    This book investigates tradeoff between security and usability in designing leakage resilient password systems (LRP) and introduces two practical LRP systems named Cover Pad and ShadowKey. It demonstrates that existing LRP systems are subject to both brute force attacks and statistical attacks and that these attacks cannot be effectively mitigated without sacrificing the usability of LRP systems. Quantitative analysis proves that a secure LRP system in practical settings imposes a considerable amount of cognitive workload unless certain secure channels are involved. The book introduces a secur

  2. Leakage-free journal bearings

    Science.gov (United States)

    Pinkus, O.; Etsion, I.

    1976-01-01

    A new concept of a journal bearing is developed which prevents side leakage of the lubricant, thus eliminating the need for sealing and collecting this leakage. The cooling of the bearing is accomplished by the prevailing circumferential flow. An analysis is performed and solutions are given for the bearing geometries and inlet pressures required to achieve the above purpose.

  3. In situ macromolecular crystallography using microbeams.

    Science.gov (United States)

    Axford, Danny; Owen, Robin L; Aishima, Jun; Foadi, James; Morgan, Ann W; Robinson, James I; Nettleship, Joanne E; Owens, Raymond J; Moraes, Isabel; Fry, Elizabeth E; Grimes, Jonathan M; Harlos, Karl; Kotecha, Abhay; Ren, Jingshan; Sutton, Geoff; Walter, Thomas S; Stuart, David I; Evans, Gwyndaf

    2012-05-01

    Despite significant progress in high-throughput methods in macromolecular crystallography, the production of diffraction-quality crystals remains a major bottleneck. By recording diffraction in situ from crystals in their crystallization plates at room temperature, a number of problems associated with crystal handling and cryoprotection can be side-stepped. Using a dedicated goniometer installed on the microfocus macromolecular crystallography beamline I24 at Diamond Light Source, crystals have been studied in situ with an intense and flexible microfocus beam, allowing weakly diffracting samples to be assessed without a manual crystal-handling step but with good signal to noise, despite the background scatter from the plate. A number of case studies are reported: the structure solution of bovine enterovirus 2, crystallization screening of membrane proteins and complexes, and structure solution from crystallization hits produced via a high-throughput pipeline. These demonstrate the potential for in situ data collection and structure solution with microbeams.

  4. Growth and dissolution of macromolecular Markov chains

    CERN Document Server

    Gaspard, Pierre

    2016-01-01

    The kinetics and thermodynamics of free living copolymerization are studied for processes with rates depending on k monomeric units of the macromolecular chain behind the unit that is attached or detached. In this case, the sequence of monomeric units in the growing copolymer is a kth-order Markov chain. In the regime of steady growth, the statistical properties of the sequence are determined analytically in terms of the attachment and detachment rates. In this way, the mean growth velocity as well as the thermodynamic entropy production and the sequence disorder can be calculated systematically. These different properties are also investigated in the regime of depolymerization where the macromolecular chain is dissolved by the surrounding solution. In this regime, the entropy production is shown to satisfy Landauer's principle.

  5. Growth and Dissolution of Macromolecular Markov Chains

    Science.gov (United States)

    Gaspard, Pierre

    2016-07-01

    The kinetics and thermodynamics of free living copolymerization are studied for processes with rates depending on k monomeric units of the macromolecular chain behind the unit that is attached or detached. In this case, the sequence of monomeric units in the growing copolymer is a kth-order Markov chain. In the regime of steady growth, the statistical properties of the sequence are determined analytically in terms of the attachment and detachment rates. In this way, the mean growth velocity as well as the thermodynamic entropy production and the sequence disorder can be calculated systematically. These different properties are also investigated in the regime of depolymerization where the macromolecular chain is dissolved by the surrounding solution. In this regime, the entropy production is shown to satisfy Landauer's principle.

  6. Dextran: A promising macromolecular drug carrier

    Directory of Open Access Journals (Sweden)

    Dhaneshwar Suneela

    2006-01-01

    Full Text Available Over the past three decades intensive efforts have been made to design novel systems able to deliver the drug more effectively to the target site. The ongoing intense search for novel and innovative drug delivery systems is predominantly a consequence of the well-established fact that the conventional dosage forms are not sufficiently effective in conveying the drug compound to its site of action and once in the target area, in releasing the active agent over a desired period of time. The potential use of macromolecular prodrugs as a means of achieving targeted drug delivery has attracted considerable interest in recent years. Macromolecules such as antibodies, lipoproteins, lectins, proteins, polypeptides, polysaccharides, natural as well as synthetic polymers offer potential applicabilities as high molecular weight carriers for various therapeutically active compounds. Dextrans serve as one of the most promising macromolecular carrier candidates for a wide variety of therapeutic agents due to their excellent physico-chemical properties and physiological acceptance. The present contribution attempts to review various features of the dextran carrier like its source, structural and physico-chemical characteristics, pharmacokinetic fate and its applications as macromolecular carrier with special emphasis on dextran prodrugs.

  7. Duct Leakage Repeatability Testing

    Energy Technology Data Exchange (ETDEWEB)

    Walker, Iain [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Sherman, Max [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2014-01-01

    Duct leakage often needs to be measured to demonstrate compliance with requirements or to determine energy or Indoor Air Quality (IAQ) impacts. Testing is often done using standards such as ASTM E1554 (ASTM 2013) or California Title 24 (California Energy Commission 2013 & 2013b), but there are several choices of methods available within the accepted standards. Determining which method to use or not use requires an evaluation of those methods in the context of the particular needs. Three factors that are important considerations are the cost of the measurement, the accuracy of the measurement and the repeatability of the measurement. The purpose of this report is to evaluate the repeatability of the three most significant measurement techniques using data from the literature and recently obtained field data. We will also briefly discuss the first two factors. The main question to be answered by this study is to determine if differences in the repeatability of these tests methods is sufficient to indicate that any of these methods is so poor that it should be excluded from consideration as an allowed procedure in codes and standards.

  8. Multifamily Envelope Leakage Model

    Energy Technology Data Exchange (ETDEWEB)

    Faakye, Omari [Consortium for Advanced Residential Buildings, Norwalk, CT (United States); Griffiths, Dianne [Consortium for Advanced Residential Buildings, Norwalk, CT (United States)

    2015-05-08

    “The cost for blower testing is high, because it is labor intensive, and it may disrupt occupants in multiple units. This high cost and disruption deter program participants, and dissuade them from pursuing energy improvements that would trigger air leakage testing, such as improvements to the building envelope.” This statement found in a 2012 report by Heschong Mahone Group for several California interests emphasizes the importance of reducing the cost and complexity of blower testing in multifamily buildings. Energy efficiency opportunities are being bypassed. The cost of single blower testing is on the order of $300. The cost for guarded blower door testing—the more appropriate test for assessing energy savings opportunities—could easily be six times that, and that’s only if you have the equipment and simultaneous access to multiple apartments. Thus, the proper test is simply not performed. This research seeks to provide an algorithm for predicting the guarded blower door test result based upon a single, total blower door test.

  9. TWO NEW DUCT LEAKAGE TESTS

    Energy Technology Data Exchange (ETDEWEB)

    ANDREWS,J.W.

    1998-12-01

    Two variations on the tests for duct leakage currently embodied in ASHRAE Standard 152P (Method of Test for Determining the Design and Seasonal Efficiencies of Residential Thermal Distribution Systems) are presented. Procedures are derived for calculating supply and return duct leakage to/from outside using these new variations. Results of these tests are compared with the original ones in Standard 152P on the basis of data collected in three New York State homes.

  10. Smoothing techniques for macromolecular global optimization

    Energy Technology Data Exchange (ETDEWEB)

    More, J.J.; Wu, Zhijun

    1995-09-01

    We study global optimization problems that arise in macromolecular modeling, and the solution of these problems via continuation and smoothing. Our results unify and extend the theory associated with the use of the Gaussian transform for smoothing. We show that the, Gaussian transform can be viewed as a special case of a generalized transform and that these generalized transforms share many of the properties of the Gaussian transform. We also show that the smoothing behavior of the generalized transform can be studied in terms of the Fourier transform and that these results indicate that the Gaussian transform has superior smoothing properties.

  11. Celebrating macromolecular crystallography: A personal perspective

    Directory of Open Access Journals (Sweden)

    Abad-Zapatero, Celerino

    2015-04-01

    Full Text Available The twentieth century has seen an enormous advance in the knowledge of the atomic structures that surround us. The discovery of the first crystal structures of simple inorganic salts by the Braggs in 1914, using the diffraction of X-rays by crystals, provided the critical elements to unveil the atomic structure of matter. Subsequent developments in the field leading to macromolecular crystallography are presented with a personal perspective, related to the cultural milieu of Spain in the late 1950’s. The journey of discovery of the author, as he developed professionally, is interwoven with the expansion of macromolecular crystallography from the first proteins (myoglobin, hemoglobin to the ‘coming of age’ of the field in 1971 and the discoveries that followed, culminating in the determination of the structure of the ribosomes at the turn of the century. A perspective is presented exploring the future of the field and also a reflection about the future generations of Spanish scientists.El siglo XX ha sido testigo del increíble avance que ha experimentado el conocimiento de la estructura atómica de la materia que nos rodea. El descubrimiento de las primeras estructuras atómicas de sales inorgánicas por los Bragg en 1914, empleando difracción de rayos X con cristales, proporcionó los elementos clave para alcanzar tal conocimiento. Posteriores desarrollos en este campo, que condujeron a la cristalografía macromolecular, se presentan aquí desde una perspectiva personal, relacionada con el contexto cultural de la España de la década de los 50. La experiencia del descubrimiento científico, durante mi desarrollo profesional, se integra en el desarrollo de la cristalografía macromolecular, desde las primeras proteínas (míoglobina y hemoglobina, hasta su madurez en 1971 que, con los posteriores descubrimientos, culmina con la determinación del la estructura del ribosoma. Asimismo, se explora el futuro de esta disciplina y se

  12. Macromolecular recognition in the Protein Data Bank

    Energy Technology Data Exchange (ETDEWEB)

    Janin, Joël, E-mail: joel.janin@ibbmc.u-psud.fr [Laboratoire d’Enzymologie et de Biochimie Structurales, UPR9063, CNRS, 91198 Gif-sur-Yvette (France); Institut de Biochimie et Biologie Moléculaire et Cellulaire, UMR8619, Bâtiment 430, Université Paris-Sud, 91405 Orsay (France); Rodier, Francis [Laboratoire d’Enzymologie et de Biochimie Structurales, UPR9063, CNRS, 91198 Gif-sur-Yvette (France); Chakrabarti, Pinak [Department of Biochemistry, Bose Institute, P-1/12 CIT Scheme VIIM, Calcutta 700 054 (India); Bahadur, Ranjit P. [Institut de Biochimie et Biologie Moléculaire et Cellulaire, UMR8619, Bâtiment 430, Université Paris-Sud, 91405 Orsay (France); Department of Biochemistry, Bose Institute, P-1/12 CIT Scheme VIIM, Calcutta 700 054 (India); Laboratoire d’Enzymologie et de Biochimie Structurales, UPR9063, CNRS, 91198 Gif-sur-Yvette (France)

    2007-01-01

    X-ray structures in the PDB illustrate both the specific recognition of two polypeptide chains in protein–protein complexes and dimeric proteins and their nonspecific interaction at crystal contacts. Crystal structures deposited in the Protein Data Bank illustrate the diversity of biological macromolecular recognition: transient interactions in protein–protein and protein–DNA complexes and permanent assemblies in homodimeric proteins. The geometric and physical chemical properties of the macromolecular interfaces that may govern the stability and specificity of recognition are explored in complexes and homodimers compared with crystal-packing interactions. It is found that crystal-packing interfaces are usually much smaller; they bury fewer atoms and are less tightly packed than in specific assemblies. Standard-size interfaces burying 1200–2000 Å{sup 2} of protein surface occur in protease–inhibitor and antigen–antibody complexes that assemble with little or no conformation changes. Short-lived electron-transfer complexes have small interfaces; the larger size of the interfaces observed in complexes involved in signal transduction and homodimers correlates with the presence of conformation changes, often implicated in biological function. Results of the CAPRI (critical assessment of predicted interactions) blind prediction experiment show that docking algorithms efficiently and accurately predict the mode of assembly of proteins that do not change conformation when they associate. They perform less well in the presence of large conformation changes and the experiment stimulates the development of novel procedures that can handle such changes.

  13. Multiscale macromolecular simulation: role of evolving ensembles.

    Science.gov (United States)

    Singharoy, A; Joshi, H; Ortoleva, P J

    2012-10-22

    Multiscale analysis provides an algorithm for the efficient simulation of macromolecular assemblies. This algorithm involves the coevolution of a quasiequilibrium probability density of atomic configurations and the Langevin dynamics of spatial coarse-grained variables denoted order parameters (OPs) characterizing nanoscale system features. In practice, implementation of the probability density involves the generation of constant OP ensembles of atomic configurations. Such ensembles are used to construct thermal forces and diffusion factors that mediate the stochastic OP dynamics. Generation of all-atom ensembles at every Langevin time step is computationally expensive. Here, multiscale computation for macromolecular systems is made more efficient by a method that self-consistently folds in ensembles of all-atom configurations constructed in an earlier step, history, of the Langevin evolution. This procedure accounts for the temporal evolution of these ensembles, accurately providing thermal forces and diffusions. It is shown that efficiency and accuracy of the OP-based simulations is increased via the integration of this historical information. Accuracy improves with the square root of the number of historical timesteps included in the calculation. As a result, CPU usage can be decreased by a factor of 3-8 without loss of accuracy. The algorithm is implemented into our existing force-field based multiscale simulation platform and demonstrated via the structural dynamics of viral capsomers.

  14. The role of macromolecular stability in desiccation tolerance.

    NARCIS (Netherlands)

    Wolkers, W.

    1998-01-01

    The work presented in this thesis concerns a study on the molecular interactions that play a role in the macromolecular stability of desiccation-tolerant higher plant organs. Fourier transform infrared microspectroscopy was used as the main experimental technique to assess macromolecular structures

  15. Air-Leakage Control Manual.

    Energy Technology Data Exchange (ETDEWEB)

    Maloney, Jim; Washington State Energy Office; United States. Bonneville Power Administration.

    1991-05-01

    This manual is for builders and designers who are interested in building energy-efficient homes. The purpose of the manual is to provide the how and why'' of controlling air leakage by means of a system called the Simple Caulk and Seal'' (SIMPLE{center dot}CS) system. This manual provides an overview of the purpose and contents of the manual; It discusses the forces that affect air leakage in homes and the benefits of controlling air leakage. Also discussed are two earlier approaches for controlling air leakage and the problems with these approaches. It describes the SIMPLE-{center dot}CS system. It outlines the standard components of the building envelope that require sealing and provides guidelines for sealing them. It outlines a step-by-step procedure for analyzing and planning the sealing effort. The procedure includes (1) identifying areas to be sealed, (2) determining the most effective and convenient stage of construction in which to do the sealing, and (3) designating the appropriate crew member or trade to be responsible for the sealing.

  16. Air-leakage control manual

    Energy Technology Data Exchange (ETDEWEB)

    Maloney, J. [Washington State Energy Office, Olympia, WA (United States)

    1991-05-01

    This manual is for builders and designers who are interested in building energy-efficient homes. The purpose of the manual is to provide the ``how and why`` of controlling air leakage by means of a system called the ``Simple Caulk and Seal`` (SIMPLE{center_dot}CS) system. This manual provides an overview of the purpose and contents of the manual; It discusses the forces that affect air leakage in homes and the benefits of controlling air leakage. Also discussed are two earlier approaches for controlling air leakage and the problems with these approaches. It describes the SIMPLE-{center_dot}CS system. It outlines the standard components of the building envelope that require sealing and provides guidelines for sealing them. It outlines a step-by-step procedure for analyzing and planning the sealing effort. The procedure includes (1) identifying areas to be sealed, (2) determining the most effective and convenient stage of construction in which to do the sealing, and (3) designating the appropriate crew member or trade to be responsible for the sealing.

  17. Practical Leakage-Resilient Symmetric Cryptography

    DEFF Research Database (Denmark)

    Faust, Sebastian; Pietrzak, Krzysztof; Schipper, Joachim

    2012-01-01

    Leakage resilient cryptography attempts to incorporate side-channel leakage into the black-box security model and designs cryptographic schemes that are provably secure within it. Informally, a scheme is leakage-resilient if it remains secure even if an adversary learns a bounded amount of arbitr......Leakage resilient cryptography attempts to incorporate side-channel leakage into the black-box security model and designs cryptographic schemes that are provably secure within it. Informally, a scheme is leakage-resilient if it remains secure even if an adversary learns a bounded amount...

  18. Functional Sub-states by High-pressure Macromolecular Crystallography.

    Science.gov (United States)

    Dhaussy, Anne-Claire; Girard, Eric

    2015-01-01

    At the molecular level, high-pressure perturbation is of particular interest for biological studies as it allows trapping conformational substates. Moreover, within the context of high-pressure adaptation of deep-sea organisms, it allows to decipher the molecular determinants of piezophily. To provide an accurate description of structural changes produced by pressure in a macromolecular system, developments have been made to adapt macromolecular crystallography to high-pressure studies. The present chapter is an overview of results obtained so far using high-pressure macromolecular techniques, from nucleic acids to virus capsid through monomeric as well as multimeric proteins.

  19. Sequential recovery of macromolecular components of the nucleolus.

    Science.gov (United States)

    Bai, Baoyan; Laiho, Marikki

    2015-01-01

    The nucleolus is involved in a number of cellular processes of importance to cell physiology and pathology, including cell stress responses and malignancies. Studies of macromolecular composition of the nucleolus depend critically on the efficient extraction and accurate quantification of all macromolecular components (e.g., DNA, RNA, and protein). We have developed a TRIzol-based method that efficiently and simultaneously isolates these three macromolecular constituents from the same sample of purified nucleoli. The recovered and solubilized protein can be accurately quantified by the bicinchoninic acid assay and assessed by polyacrylamide gel electrophoresis or by mass spectrometry. We have successfully applied this approach to extract and quantify the responses of all three macromolecular components in nucleoli after drug treatments of HeLa cells, and conducted RNA-Seq analysis of the nucleolar RNA.

  20. Issues behind Competitiveness and Carbon Leakage

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2008-07-01

    This report explores the vulnerability of heavy industry to carbon leakage and competitiveness loss. It reviews the existing literature on competitiveness and carbon leakage under uneven climate policies. It also suggests a statistical method to track carbon leakage, and applies this methodology to Phase I of the EU emissions trading scheme, for various industrial activities: iron and steel, cement, aluminium and refineries. Finally, it reviews measures to mitigate carbon leakage, as discussed in Australia, Canada, Europe, New Zealand and the US.

  1. Heat exchanger leakage problem location

    Directory of Open Access Journals (Sweden)

    Jícha Miroslav

    2012-04-01

    Full Text Available Recent compact heat exchangers are very often assembled from numerous parts joined together to separate heat transfer fluids and to form the required heat exchanger arrangement. Therefore, the leak tightness is very important property of the compact heat exchangers. Although, the compact heat exchangers have been produced for many years, there are still technological problems associated with manufacturing of the ideal connection between the individual parts, mainly encountered with special purpose heat exchangers, e.g. gas turbine recuperators. This paper describes a procedure used to identify the leakage location inside the prime surface gas turbine recuperator. For this purpose, an analytical model of the leaky gas turbine recuperator was created to assess its performance. The results obtained are compared with the experimental data which were acquired during the recuperator thermal performance analysis. The differences between these two data sets are used to indicate possible leakage areas.

  2. Heat exchanger leakage problem location

    Science.gov (United States)

    Hejčík, Jiří; Jícha, Miroslav

    2012-04-01

    Recent compact heat exchangers are very often assembled from numerous parts joined together to separate heat transfer fluids and to form the required heat exchanger arrangement. Therefore, the leak tightness is very important property of the compact heat exchangers. Although, the compact heat exchangers have been produced for many years, there are still technological problems associated with manufacturing of the ideal connection between the individual parts, mainly encountered with special purpose heat exchangers, e.g. gas turbine recuperators. This paper describes a procedure used to identify the leakage location inside the prime surface gas turbine recuperator. For this purpose, an analytical model of the leaky gas turbine recuperator was created to assess its performance. The results obtained are compared with the experimental data which were acquired during the recuperator thermal performance analysis. The differences between these two data sets are used to indicate possible leakage areas.

  3. The solvent component of macromolecular crystals

    Energy Technology Data Exchange (ETDEWEB)

    Weichenberger, Christian X. [European Academy of Bozen/Bolzano (EURAC), Viale Druso 1, Bozen/Bolzano, I-39100 Südtirol/Alto Adige (Italy); Afonine, Pavel V. [Lawrence Berkeley National Laboratory (LBNL), 1 Cyclotron Road, Mail Stop 64R0121, Berkeley, CA 94720 (United States); Kantardjieff, Katherine [California State University, San Marcos, CA 92078 (United States); Rupp, Bernhard, E-mail: br@hofkristallamt.org [k.-k. Hofkristallamt, 991 Audrey Place, Vista, CA 92084 (United States); Medical University of Innsbruck, Schöpfstrasse 41, A-6020 Innsbruck (Austria)

    2015-04-30

    On average, the mother liquor or solvent and its constituents occupy about 50% of a macromolecular crystal. Ordered as well as disordered solvent components need to be accurately accounted for in modelling and refinement, often with considerable complexity. The mother liquor from which a biomolecular crystal is grown will contain water, buffer molecules, native ligands and cofactors, crystallization precipitants and additives, various metal ions, and often small-molecule ligands or inhibitors. On average, about half the volume of a biomolecular crystal consists of this mother liquor, whose components form the disordered bulk solvent. Its scattering contributions can be exploited in initial phasing and must be included in crystal structure refinement as a bulk-solvent model. Concomitantly, distinct electron density originating from ordered solvent components must be correctly identified and represented as part of the atomic crystal structure model. Herein, are reviewed (i) probabilistic bulk-solvent content estimates, (ii) the use of bulk-solvent density modification in phase improvement, (iii) bulk-solvent models and refinement of bulk-solvent contributions and (iv) modelling and validation of ordered solvent constituents. A brief summary is provided of current tools for bulk-solvent analysis and refinement, as well as of modelling, refinement and analysis of ordered solvent components, including small-molecule ligands.

  4. Macromolecular components of tomato fruit pectin.

    Science.gov (United States)

    Fishman, M L; Gross, K C; Gillespie, D T; Sondey, S M

    1989-10-01

    Chelate and alkaline-soluble pectin extracted from cell walls of pericarp tissue from mature green, turning, and red ripe (Lycopersicon esculentum Mill.) fruit (cv. Rutgers), were studied by high-performance size-exclusion chromatography. Computer-aided curve fitting of the chromatograms to a series of Gaussian-shaped components revealed that pectin from all fractions was composed of a linear combination of five macromolecular-sized species. The relative sizes of these macromolecules as obtained from their radii of gyration were 1:2:4:8:16. Dialysis against 0.05 M NaCl induced partial dissociation of the biopolymers. Apparently, the weight fraction of smaller sized species increased at the expense of larger ones. Also, the dissociation produced low-molecular-weight fragments. Behavior in the presence of 0.05 M NaCl led to the conclusion that cell wall pectin acted as if it were an aggregated mosaic, held together at least partially through noncovalent interactions.

  5. An upper limit for macromolecular crowding effects

    Directory of Open Access Journals (Sweden)

    Miklos Andrew C

    2011-05-01

    Full Text Available Abstract Background Solutions containing high macromolecule concentrations are predicted to affect a number of protein properties compared to those properties in dilute solution. In cells, these macromolecular crowders have a large range of sizes and can occupy 30% or more of the available volume. We chose to study the stability and ps-ns internal dynamics of a globular protein whose radius is ~2 nm when crowded by a synthetic microgel composed of poly(N-isopropylacrylamide-co-acrylic acid with particle radii of ~300 nm. Results Our studies revealed no change in protein rotational or ps-ns backbone dynamics and only mild (~0.5 kcal/mol at 37°C, pH 5.4 stabilization at a volume occupancy of 70%, which approaches the occupancy of closely packing spheres. The lack of change in rotational dynamics indicates the absence of strong crowder-protein interactions. Conclusions Our observations are explained by the large size discrepancy between the protein and crowders and by the internal structure of the microgels, which provide interstitial spaces and internal pores where the protein can exist in a dilute solution-like environment. In summary, microgels that interact weakly with proteins do not strongly influence protein dynamics or stability because these large microgels constitute an upper size limit on crowding effects.

  6. Macromolecular networks and intelligence in microorganisms

    Science.gov (United States)

    Westerhoff, Hans V.; Brooks, Aaron N.; Simeonidis, Evangelos; García-Contreras, Rodolfo; He, Fei; Boogerd, Fred C.; Jackson, Victoria J.; Goncharuk, Valeri; Kolodkin, Alexey

    2014-01-01

    Living organisms persist by virtue of complex interactions among many components organized into dynamic, environment-responsive networks that span multiple scales and dimensions. Biological networks constitute a type of information and communication technology (ICT): they receive information from the outside and inside of cells, integrate and interpret this information, and then activate a response. Biological networks enable molecules within cells, and even cells themselves, to communicate with each other and their environment. We have become accustomed to associating brain activity – particularly activity of the human brain – with a phenomenon we call “intelligence.” Yet, four billion years of evolution could have selected networks with topologies and dynamics that confer traits analogous to this intelligence, even though they were outside the intercellular networks of the brain. Here, we explore how macromolecular networks in microbes confer intelligent characteristics, such as memory, anticipation, adaptation and reflection and we review current understanding of how network organization reflects the type of intelligence required for the environments in which they were selected. We propose that, if we were to leave terms such as “human” and “brain” out of the defining features of “intelligence,” all forms of life – from microbes to humans – exhibit some or all characteristics consistent with “intelligence.” We then review advances in genome-wide data production and analysis, especially in microbes, that provide a lens into microbial intelligence and propose how the insights derived from quantitatively characterizing biomolecular networks may enable synthetic biologists to create intelligent molecular networks for biotechnology, possibly generating new forms of intelligence, first in silico and then in vivo. PMID:25101076

  7. Macromolecular Topography Leaps into the Digital Age

    Science.gov (United States)

    Lovelace, J.; Bellamy, H.; Snell, E. H.; Borgstahl, G.

    2003-01-01

    A low-cost, real-time digital topography system is under development which will replace x-ray film and nuclear emulsion plates. The imaging system is based on an inexpensive surveillance camera that offers a 1000x1000 array of 8 im square pixels, anti-blooming circuitry, and very quick read out. Currently, the system directly converts x-rays to an image with no phosphor. The system is small and light and can be easily adapted to work with other crystallographic equipment. Preliminary images have been acquired of cubic insulin at the NSLS x26c beam line. NSLS x26c was configured for unfocused monochromatic radiation. Six reflections were collected with stills spaced from 0.002 to 0.001 degrees apart across the entire oscillation range that the reflections were in diffracting condition. All of the reflections were rotated to the vertical to reduce Lorentz and beam related effects. This particular CCD is designed for short exposure applications (much less than 1 sec) and so has a relatively high dark current leading to noisy raw images. The images are processed to remove background and other system noise with a multi-step approach including the use of wavelets, histogram, and mean window filtering. After processing, animations were constructed with the corresponding reflection profile to show the diffraction of the crystal volume vs. the oscillation angle as well as composite images showing the parts of the crystal with the strongest diffraction for each reflection. The final goal is to correlate features seen in reflection profiles captured with fine phi slicing to those seen in the topography images. With this development macromolecular topography finally comes into the digital age.

  8. Macromolecular networks and intelligence in microorganisms

    Directory of Open Access Journals (Sweden)

    Hans V Westerhoff

    2014-07-01

    Full Text Available Living organisms persist by virtue of complex interactions among many components organized into dynamic, environment-responsive networks that span multiple scales and dimensions. Biological networks constitute a type of Information and Communication Technology (ICT: they receive information from the outside and inside of cells, integrate and interpret this information, and then activate a response. Biological networks enable molecules within cells, and even cells themselves, to communicate with each other and their environment. We have become accustomed to associating brain activity – particularly activity of the human brain – with a phenomenon we call intelligence. Yet, four billion years of evolution could have selected networks with topologies and dynamics that confer traits analogous to this intelligence, even though they were outside the intercellular networks of the brain. Here, we explore how macromolecular networks in microbes confer intelligent characteristics, such as memory, anticipation, adaptation and reflection and we review current understanding of how network organization reflects the type of intelligence required for the environments in which they were selected. We propose that, if we were to leave terms such as human and brain out of the defining features of intelligence, all forms of life – from microbes to humans – exhibit some or all characteristics consistent with intelligence. We then review advances in genome-wide data production and analysis, especially in microbes, that provide a lens into microbial intelligence and propose how the insights derived from quantitatively characterizing biomolecular networks may enable synthetic biologists to create intelligent molecular networks for biotechnology, possibly generating new forms of intelligence, first in silico and then in vivo.

  9. Macromolecular Antioxidants and Dietary Fiber in Edible Seaweeds.

    Science.gov (United States)

    Sanz-Pintos, Nerea; Pérez-Jiménez, Jara; Buschmann, Alejandro H; Vergara-Salinas, José Rodrigo; Pérez-Correa, José Ricardo; Saura-Calixto, Fulgencio

    2017-02-01

    Seaweeds are rich in different bioactive compounds with potential uses in drugs, cosmetics and the food industry. The objective of this study was to analyze macromolecular antioxidants or nonextractable polyphenols, in several edible seaweed species collected in Chile (Gracilaria chilensis, Callophyllis concepcionensis, Macrocystis pyrifera, Scytosyphon lomentaria, Ulva sp. and Enteromorpha compressa), including their 1st HPLC characterization. Macromolecular antioxidants are commonly ignored in studies of bioactive compounds. They are associated with insoluble dietary fiber and exhibit significant biological activity, with specific features that are different from those of both dietary fiber and extractable polyphenols. We also evaluated extractable polyphenols and dietary fiber, given their relationship with macromolecular antioxidants. Our results show that macromolecular antioxidants are a major polyphenol fraction (averaging 42% to total polyphenol content), with hydroxycinnamic acids, hydroxybenzoic acids and flavonols being the main constituents. This fraction also showed remarkable antioxidant capacity, as determined by 2 complementary assays. The dietary fiber content was over 50% of dry weight, with some samples exhibiting the target proportionality between soluble and insoluble dietary fiber for adequate nutrition. Overall, our data show that seaweed could be an important source of commonly ignored macromolecular antioxidants.

  10. Complex Macromolecular Architectures by Living Cationic Polymerization

    KAUST Repository

    Alghamdi, Reem D.

    2015-05-01

    Poly (vinyl ether)-based graft polymers have been synthesized by the combination of living cationic polymerization of vinyl ethers with other living or controlled/ living polymerization techniques (anionic and ATRP). The process involves the synthesis of well-defined homopolymers (PnBVE) and co/terpolymers [PnBVE-b-PCEVE-b-PSiDEGVE (ABC type) and PSiDEGVE-b-PnBVE-b-PSiDEGVE (CAC type)] by sequential living cationic polymerization of n-butyl vinyl ether (nBVE), 2-chloroethyl vinyl ether (CEVE) and tert-butyldimethylsilyl ethylene glycol vinyl ether (SiDEGVE), using mono-functional {[n-butoxyethyl acetate (nBEA)], [1-(2-chloroethoxy) ethyl acetate (CEEA)], [1-(2-(2-(t-butyldimethylsilyloxy)ethoxy) ethoxy) ethyl acetate (SiDEGEA)]} or di-functional [1,4-cyclohexanedimethanol di(1-ethyl acetate) (cHMDEA), (VEMOA)] initiators. The living cationic polymerizations of those monomers were conducted in hexane at -20 0C using Et3Al2Cl3 (catalyst) in the presence of 1 M AcOEt base.[1] The PCEVE segments of the synthesized block terpolymers were then used to react with living macroanions (PS-DPE-Li; poly styrene diphenyl ethylene lithium) to afford graft polymers. The quantitative desilylation of PSiDEGVE segments by n-Bu4N+F- in THF at 0 °C led to graft co- and terpolymers in which the polyalcohol is the outer block. These co-/terpolymers were subsequently subjected to “grafting-from” reactions by atom transfer radical polymerization (ATRP) of styrene to afford more complex macromolecular architectures. The base assisted living cationic polymerization of vinyl ethers were also used to synthesize well-defined α-hydroxyl polyvinylether (PnBVE-OH). The resulting polymers were then modified into an ATRP macro-initiator for the synthesis of well-defined block copolymers (PnBVE-b-PS). Bifunctional PnBVE with terminal malonate groups was also synthesized and used as a precursor for more complex architectures such as H-shaped block copolymer by “grafting-from” or

  11. LEAKAGE OF COLONIC ANASTOMOSIS AFTER COLON RESECTION

    Institute of Scientific and Technical Information of China (English)

    Kanellos I; Pramateftakis MG

    2004-01-01

    Objective To present the diagnosis and management of anastomotic leakage after colon resection. Methods Early diagnosis and urgent therapeutic intervention are required in order to avert life-threatening conditions that may be caused by anastomotic leakage. Results The diagnosis of anastomotic leakage is based on clinical features, peripheral blood investigations and abdominal computed tomography (CT) scan. Major leaks are defined by symptoms of peritonitis and septicaemia due to leakage. Major leaks should be managed operatively. Minor leaks can be managed conservatively with successful outcomes. Conclusion Leakage of colonic anastomosis remains the most serious complication after colon resection. It is a major cause of postoperative morbidity and mortality. A high index of suspicion is required in order to detect early, nonspecific signs of a leakage and urgent surgical intervention is usually required to avert life-threatening events.

  12. Energy Conservation Through Duct Leakage Reduction

    Science.gov (United States)

    2004-02-26

    Energy Conservation Through Duct Leakage Reduction February 26, 2004 Rich Glatt – Lindab Inc. Report Documentation Page Form ApprovedOMB No. 0704...4. TITLE AND SUBTITLE Energy Conservation Through Duct Leakage Reduction 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6...Wall – DW that installs like SW - easiest installing DW system on the market – Eliminates the need for costly flanged connections – SMACNA Leakage

  13. Leakage-current properties of encapsulants

    Science.gov (United States)

    Wen, L. C.

    A theoretical modeling of leakage current in ethylene vinyl acetate (EVA) and polyvinyl butyral (PVB) modules is being developed and is described. The modeling effort derives mathematical relationships for the bulk and surface conductivites of EVA and PVB, the surface conductivities of glass and polymeric films, and the EVA and PVB pottants, all as functions of environmental parameters. Results from the modeling indicate that for glass/EVA, the glass surface controls the interfacial conductivity, although EVA bulk conductivity controls total leakage current. For PVB/glass, the interface conductivity controls leakage currents for relative humidity (RH) less than 40 to 50%, but PVB bulk conductivity controls leakage current above 50% RH.

  14. Macromolecular crystallography beamline X25 at the NSLS.

    Science.gov (United States)

    Héroux, Annie; Allaire, Marc; Buono, Richard; Cowan, Matthew L; Dvorak, Joseph; Flaks, Leon; Lamarra, Steven; Myers, Stuart F; Orville, Allen M; Robinson, Howard H; Roessler, Christian G; Schneider, Dieter K; Shea-McCarthy, Grace; Skinner, John M; Skinner, Michael; Soares, Alexei S; Sweet, Robert M; Berman, Lonny E

    2014-05-01

    Beamline X25 at the NSLS is one of the five beamlines dedicated to macromolecular crystallography operated by the Brookhaven National Laboratory Macromolecular Crystallography Research Resource group. This mini-gap insertion-device beamline has seen constant upgrades for the last seven years in order to achieve mini-beam capability down to 20 µm × 20 µm. All major components beginning with the radiation source, and continuing along the beamline and its experimental hutch, have changed to produce a state-of-the-art facility for the scientific community.

  15. Estimating leakage from forest carbon sequestration programs

    Energy Technology Data Exchange (ETDEWEB)

    Murray, B.C. [RTI International, Research Triangle Park, NC (United States); McCarl, B.A. [Texas A and M Univ., College Station, TX (United States). Dept. of Agricultural Economics; Lee, H.C. [Western Ontario Univ., London, ON (Canada). Dept. of Economics

    2003-03-01

    Nearly half of all terrestrial carbon is stored in forest ecosystems. Land use changes such as deforestation were responsible for nearly 20 per cent of carbon dioxide (CO{sub 2}) released in the atmosphere worldwide between 1989 to 1998. This paper developed an estimation procedure that addressed the magnitude of potential leakage from carbon sequestration projects in the forest sector, including the conversion of land from agriculture to forest. Leakage occurs when a program's direct carbon benefits are undermined by carbon releases elsewhere. Leakage directly undermines greenhouse gas (GHG) emission reducing actions and should be considered when designing and evaluating policies. Leakage should be deducted from the carbon credits granted to mitigation projects, and accounting rules and guidelines for crediting carbon sequestration projects. Analytic, econometric, and sector-level optimization models were combined to estimate leakage from different forest carbon sequestration activities. The FASOM forest and agricultural sector model was used to investigate empirical leakage consequences in 4 categories: forest setasides, avoided deforestation, afforestation, and a combination of afforestation and avoided deforestation. The interaction of market forces that cause leakage from forest sector projects was investigated. Results suggested that leakage from geographically targeted mitigation projects can be sizeable. For small projects, leakage tends to be larger in proportion to direct project benefits than larger programs or policies. It was suggested that if leakage is more pronounced in forest carbon projects than energy sector projects, this could affect the terms of trade for the credits generated by different sources and thereby affect the optimal portfolio of mitigation options. It was concluded that policy designers and market makers should account for leakage effects when enabling exchanges of GHG offsets.

  16. Forest Carbon Leakage Quantification Methods and Their Suitability for Assessing Leakage in REDD

    Directory of Open Access Journals (Sweden)

    Sabine Henders

    2012-01-01

    Full Text Available This paper assesses quantification methods for carbon leakage from forestry activities for their suitability in leakage accounting in a future Reducing Emissions from Deforestation and Forest Degradation (REDD mechanism. To that end, we first conducted a literature review to identify specific pre-requisites for leakage assessment in REDD. We then analyzed a total of 34 quantification methods for leakage emissions from the Clean Development Mechanism (CDM, the Verified Carbon Standard (VCS, the Climate Action Reserve (CAR, the CarbonFix Standard (CFS, and from scientific literature sources. We screened these methods for the leakage aspects they address in terms of leakage type, tools used for quantification and the geographical scale covered. Results show that leakage methods can be grouped into nine main methodological approaches, six of which could fulfill the recommended REDD leakage requirements if approaches for primary and secondary leakage are combined. The majority of methods assessed, address either primary or secondary leakage; the former mostly on a local or regional and the latter on national scale. The VCS is found to be the only carbon accounting standard at present to fulfill all leakage quantification requisites in REDD. However, a lack of accounting methods was identified for international leakage, which was addressed by only two methods, both from scientific literature.

  17. Radiofrequency radiation leakage from microwave ovens.

    Science.gov (United States)

    Lahham, Adnan; Sharabati, Afifeh

    2013-12-01

    This work presents data on the amount of radiation leakage from 117 microwave ovens in domestic and restaurant use in the West Bank, Palestine. The study of leakage is based on the measurements of radiation emissions from the oven in real-life conditions by using a frequency selective field strength measuring system. The power density from individual ovens was measured at a distance of 1 m and at the height of centre of door screen. The tested ovens were of different types, models with operating powers between 1000 and 1600 W and ages ranging from 1 month to >20 y, including 16 ovens with unknown ages. The amount of radiation leakage at a distance of 1 m was found to vary from 0.43 to 16.4 μW cm(-2) with an average value equalling 3.64 μW cm(-2). Leakages from all tested microwave ovens except for seven ovens (∼6 % of the total) were below 10 μW cm(-2). The highest radiation leakage from any tested oven was ∼16.4 μW cm(-2), and found in two cases only. In no case did the leakage exceed the limit of 1 mW cm(-2) recommended by the ICNIRP for 2.45-GHz radiofrequency. This study confirms a linear correlation between the amount of leakage and both oven age and operating power, with a stronger dependence of leakage on age.

  18. Predicting Envelope Leakage in Attached Dwellings

    Energy Technology Data Exchange (ETDEWEB)

    Faakye, O.; Arena, L.; Griffiths, D.

    2013-07-01

    The most common method for measuring air leakage is to use a single blower door to pressurize and/or depressurize the test unit. In detached housing, the test unit is the entire home and the single blower door measures air leakage to the outside. In attached housing, this 'single unit', 'total', or 'solo' test method measures both the air leakage between adjacent units through common surfaces as well air leakage to the outside. Measuring and minimizing this total leakage is recommended to avoid indoor air quality issues between units, reduce energy losses to the outside, reduce pressure differentials between units, and control stack effect. However, two significant limitations of the total leakage measurement in attached housing are: for retrofit work, if total leakage is assumed to be all to the outside, the energy benefits of air sealing can be significantly over predicted; for new construction, the total leakage values may result in failing to meet an energy-based house tightness program criterion. The scope of this research is to investigate an approach for developing a viable simplified algorithm that can be used by contractors to assess energy efficiency program qualification and/or compliance based upon solo test results.

  19. Leakage-resilient cryptography from minimal assumptions

    DEFF Research Database (Denmark)

    Hazay, Carmit; López-Alt, Adriana; Wee, Hoeteck;

    2013-01-01

    We present new constructions of leakage-resilient cryptosystems, which remain provably secure even if the attacker learns some arbitrary partial information about their internal secret key. For any polynomial ℓ, we can instantiate these schemes so as to tolerate up to ℓ bits of leakage. While the...

  20. Markovian Processes for Quantitative Information Leakage

    DEFF Research Database (Denmark)

    Biondi, Fabrizio

    and randomized processes with Markovian models and to compute their information leakage for a very general model of attacker. We present the QUAIL tool that automates such analysis and is able to compute the information leakage of an imperative WHILE language. Finally, we show how to use QUAIL to analyze some...

  1. Generating triangulated macromolecular surfaces by Euclidean Distance Transform.

    Directory of Open Access Journals (Sweden)

    Dong Xu

    Full Text Available Macromolecular surfaces are fundamental representations of their three-dimensional geometric shape. Accurate calculation of protein surfaces is of critical importance in the protein structural and functional studies including ligand-protein docking and virtual screening. In contrast to analytical or parametric representation of macromolecular surfaces, triangulated mesh surfaces have been proved to be easy to describe, visualize and manipulate by computer programs. Here, we develop a new algorithm of EDTSurf for generating three major macromolecular surfaces of van der Waals surface, solvent-accessible surface and molecular surface, using the technique of fast Euclidean Distance Transform (EDT. The triangulated surfaces are constructed directly from volumetric solids by a Vertex-Connected Marching Cube algorithm that forms triangles from grid points. Compared to the analytical result, the relative error of the surface calculations by EDTSurf is <2-4% depending on the grid resolution, which is 1.5-4 times lower than the methods in the literature; and yet, the algorithm is faster and costs less computer memory than the comparative methods. The improvements in both accuracy and speed of the macromolecular surface determination should make EDTSurf a useful tool for the detailed study of protein docking and structure predictions. Both source code and the executable program of EDTSurf are freely available at http://zhang.bioinformatics.ku.edu/EDTSurf.

  2. Two-center-multipole expansion method: application to macromolecular systems

    DEFF Research Database (Denmark)

    Solov'yov, Ilia; Yakubovich, Alexander V.; Solov'yov, Andrey V.;

    2007-01-01

    We propose a theoretical method for the calculation of the interaction energy between macromolecular systems at large distances. The method provides a linear scaling of the computing time with the system size and is considered as an alternative to the well-known fast multipole method. Its...

  3. Leakage-Resilient Circuits without Computational Assumptions

    DEFF Research Database (Denmark)

    Dziembowski, Stefan; Faust, Sebastian

    2012-01-01

    Physical cryptographic devices inadvertently leak information through numerous side-channels. Such leakage is exploited by so-called side-channel attacks, which often allow for a complete security breache. A recent trend in cryptography is to propose formal models to incorporate leakage into the ......Physical cryptographic devices inadvertently leak information through numerous side-channels. Such leakage is exploited by so-called side-channel attacks, which often allow for a complete security breache. A recent trend in cryptography is to propose formal models to incorporate leakage...... into the model and to construct schemes that are provably secure within them. We design a general compiler that transforms any cryptographic scheme, e.g., a block-cipher, into a functionally equivalent scheme which is resilient to any continual leakage provided that the following three requirements are satisfied...

  4. Climate Policy and Carbon Leakage

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2008-07-01

    This report explores the effects of the EU emissions trading scheme on the aluminium sector (i.e. competitiveness loss and carbon leakage). With its very high electricity intensity, primary aluminium stands out in the heavy industry picture: a sector whose emissions are not capped in the present EU ETS, European aluminium smelters still stand to lose profit margins and, possibly, market shares, as electricity prices increase following CO2 caps on generators' emissions - the famous pass-through of CO2 prices into electricity prices. The analysis includes a method of quantification of this issue, based on two indicators: profit margins and trade flows. As the EU is at the forefront of such policy, the paper provides policy messages to all countries on how trade exposed energy-intensive industries can be 'moved' by carbon constraint. This also is a contentious topic in Australia, Japan, New Zealand, and the US, where ambitious climate policies -- including cap-and-trade systems -- are currently debated.

  5. Experimental evaluation of clinical colon anastomotic leakage

    DEFF Research Database (Denmark)

    Pommergaard, Hans-Christian

    2014-01-01

    has been improved and is now thoroughly validated. If used by researchers worldwide, comparison of results is possible. Pure ischemia/anoxia may be too simple an approach to create a clinical leakage model. Thus, future models could focus on multiple risk factors. Conclusively, large-scale clinical...... mice. The number of sutures in the intervention group was reduced to produce a suitable leakage rate. Moreover, the analgesia and suture material were changed in order to optimize the model. In the final experiment, the four-suture anastomoses resulted in a 40% leakage rate in the intervention groups...

  6. Architectural Leakage Power Minimization of Scratchpad memories

    Directory of Open Access Journals (Sweden)

    S. Paraneetharan,

    2012-03-01

    Full Text Available Partitioning a memory into multiple blocks that can be independently accessed is a widely used technique to reduce its dynamic power. For embedded systems, its benefits can be even pushed further by properly matching the partition to the memory access patterns. When leakage energy comes into play, however, idle memory blocks must be put into a proper low-leakage sleep state to actually save energy when not accessed. In this case, the matching becomes an instance of the power management problem, because moving to and from this sleep state requires additional energy. An effective solution to the problem of the leakage-aware partitioning of a memory into disjoint sub blocks, in particular, target scratchpad memories, which are commonly used in some embedded systems as a replacement for caches. By this approach, it is able to provide an optimal solution to the leakage-aware partitioning problem.

  7. High charge, low leakage tantalum powders

    Energy Technology Data Exchange (ETDEWEB)

    Schiele, E. K.; Manley Jr., R. V.; Rerat, C. F.

    1985-10-01

    Tantalum powders for electrolytic capacitors having improved electrical capacity and low direct current leakage characteristics are produced by the introduction of combinations of carbon, nitrogen and sulfur-containing materials.

  8. Controlled architecture for improved macromolecular memory within polymer networks.

    Science.gov (United States)

    DiPasquale, Stephen A; Byrne, Mark E

    2016-08-01

    This brief review analyzes recent developments in the field of living/controlled polymerization and the potential of this technique for creating imprinted polymers with highly structured architecture with macromolecular memory. As a result, it is possible to engineer polymers at the molecular level with increased homogeneity relating to enhanced template binding and transport. Only recently has living/controlled polymerization been exploited to decrease heterogeneity and substantially improve the efficiency of the imprinting process for both highly and weakly crosslinked imprinted polymers. Living polymerization can be utilized to create imprinted networks that are vastly more efficient than similar polymers produced using conventional free radical polymerization, and these improvements increase the role that macromolecular memory can play in the design and engineering of new drug delivery and sensing platforms.

  9. Refinement of macromolecular structures against neutron data with SHELXL2013.

    Science.gov (United States)

    Gruene, Tim; Hahn, Hinrich W; Luebben, Anna V; Meilleur, Flora; Sheldrick, George M

    2014-02-01

    Some of the improvements in SHELX2013 make SHELXL convenient to use for refinement of macromolecular structures against neutron data without the support of X-ray data. The new NEUT instruction adjusts the behaviour of the SFAC instruction as well as the default bond lengths of the AFIX instructions. This work presents a protocol on how to use SHELXL for refinement of protein structures against neutron data. It includes restraints extending the Engh & Huber [Acta Cryst. (1991), A47, 392-400] restraints to H atoms and discusses several of the features of SHELXL that make the program particularly useful for the investigation of H atoms with neutron diffraction. SHELXL2013 is already adequate for the refinement of small molecules against neutron data, but there is still room for improvement, like the introduction of chain IDs for the refinement of macromolecular structures.

  10. Stochastic reaction–diffusion algorithms for macromolecular crowding

    Science.gov (United States)

    Sturrock, Marc

    2016-06-01

    Compartment-based (lattice-based) reaction–diffusion algorithms are often used for studying complex stochastic spatio-temporal processes inside cells. In this paper the influence of macromolecular crowding on stochastic reaction–diffusion simulations is investigated. Reaction–diffusion processes are considered on two different kinds of compartmental lattice, a cubic lattice and a hexagonal close packed lattice, and solved using two different algorithms, the stochastic simulation algorithm and the spatiocyte algorithm (Arjunan and Tomita 2010 Syst. Synth. Biol. 4, 35–53). Obstacles (modelling macromolecular crowding) are shown to have substantial effects on the mean squared displacement and average number of molecules in the domain but the nature of these effects is dependent on the choice of lattice, with the cubic lattice being more susceptible to the effects of the obstacles. Finally, improvements for both algorithms are presented.

  11. The vibron dressing in α-helicoidal macromolecular chains

    Institute of Scientific and Technical Information of China (English)

    D.(C)evizovi(c); S.Galovi(c); A.Reshetnyak; Z.Ivi(c)

    2013-01-01

    We present a study of the physical properties of the vibrational excitation in α-helicoidal macromolecular chains,caused by the interaction with acoustical and optical phonon modes.The influence of the temperature and the basic system parameters on the vibron dressing have been analyzed by employing the simple mean-field approach based on the variational extension of the Lang-Firsov unitary transformation.The applied approach predicts a region in system parameter space where one has an abrupt transition from a partially dressed (light and mobile) to a fully dressed (immobile) vibron state.We found that the boundary of this region depends on system temperature and the type of bond among structural elements in the macromolecular chain.

  12. Isotope labeling for NMR studies of macromolecular structure and interactions

    Energy Technology Data Exchange (ETDEWEB)

    Wright, P.E. [Scripps Research Institute, La Jolla, CA (United States)

    1994-12-01

    Implementation of biosynthetic methods for uniform or specific isotope labeling of proteins, coupled with the recent development of powerful heteronuclear multidimensional NMR methods, has led to a dramatic increase in the size and complexity of macromolecular systems that are now amenable to NMR structural analysis. In recent years, a new technology has emerged that combines uniform {sup 13}C, {sup 15}N labeling with heteronuclear multidimensional NMR methods to allow NMR structural studies of systems approaching 25 to 30 kDa in molecular weight. In addition, with the introduction of specific {sup 13}C and {sup 15}N labels into ligands, meaningful NMR studies of complexes of even higher molecular weight have become feasible. These advances usher in a new era in which the earlier, rather stringent molecular weight limitations have been greatly surpassed and NMR can begin to address many central biological problems that involve macromolecular structure, dynamics, and interactions.

  13. A macromolecular model for the endothelial surface layer

    Science.gov (United States)

    Harden, James; Danova-Okpetu, Darina; Grest, Gary

    2006-03-01

    The endothelial surface layer (ESL) is a micron-scale macromolecular lining of the luminal side of blood vessels composed of proteoglycans, glycoproteins, polysaccharides and associated plasma proteins all in dynamic equilibrium. It has numerous physiological roles including the regulation of blood flow and microvascular permeability, and active participation in mechanotransduction and stress regulation, coagulation, cell adhesion, and inflammatory response. The dynamic structure and the mechanical properties of the ESL are crucial for many of its physiological properties. We present a topological model for the ESL composed of three basic macromolecular elements: branched proteoglycans, linear polysaccharide chains, and small plasma proteins. The model was studied using non-equilibrium molecular dynamics simulations and compared with scaling theories for associating tethered polymers. We discuss the observed dynamical and mechanical properties of the ESL captured by this model, and the possible physical insight it provides into the physiological behavior of the ESL.

  14. Temperature-dependent macromolecular X-ray crystallography

    Energy Technology Data Exchange (ETDEWEB)

    Weik, Martin, E-mail: martin.weik@ibs.fr; Colletier, Jacques-Philippe [CEA, IBS, Laboratoire de Biophysique Moléculaire, F-38054 Grenoble (France); CNRS, UMR5075, F-38027 Grenoble (France); Université Joseph Fourier, F-38000 Grenoble (France)

    2010-04-01

    The dynamical behaviour of crystalline macromolecules and their surrounding solvent as a function of cryo-temperature is reviewed. X-ray crystallography provides structural details of biological macromolecules. Whereas routine data are collected close to 100 K in order to mitigate radiation damage, more exotic temperature-controlled experiments in a broader temperature range from 15 K to room temperature can provide both dynamical and structural insights. Here, the dynamical behaviour of crystalline macromolecules and their surrounding solvent as a function of cryo-temperature is reviewed. Experimental strategies of kinetic crystallography are discussed that have allowed the generation and trapping of macromolecular intermediate states by combining reaction initiation in the crystalline state with appropriate temperature profiles. A particular focus is on recruiting X-ray-induced changes for reaction initiation, thus unveiling useful aspects of radiation damage, which otherwise has to be minimized in macromolecular crystallography.

  15. Study on Detection Technique for Pipeline Leakage

    Institute of Scientific and Technical Information of China (English)

    李健; 王立坤; 周琰; 靳世久

    2003-01-01

    Pipeline integrity defect is a considerable portion in all the defects. Therefore, the study on detection technique is of great concern to the owners of pipelines. A real-time monitoring system of pipeline defect is established. For unexpected accidents of pipeline leakage, several methods of signal processing, including wavelet analysis are utilized. The leakage can be located accurately in time. This system is applied to many long distance pipelines in China, which has made great contributions to the economy.

  16. Single-particle cryo-electron microscopy of macromolecular assemblies

    OpenAIRE

    Cheng, Kimberley

    2009-01-01

    In this thesis, single-particle cryo-electron microscopy (cryo-EM) was used to study the structure of three macromolecular assemblies: the two hemocyanin isoforms from Rapana thomasiana, the Pyrococcus furiosus chaperonin, and the ribosome from Escherichia coli. Hemocyanins are large respiratory proteins in arthropods and molluscs. Most molluscan hemocyanins exist as two distinct isoforms composed of related polypeptides. In most species the two isoforms differ in terms of their oligomeric st...

  17. Facilitating structure determination: workshop on robotics andautomation in macromolecular crystallography

    Energy Technology Data Exchange (ETDEWEB)

    Ralston, Corie; Cork, C.W.; McDermott, G.; Earnest, T.N.

    2006-03-28

    As part of the annual Advanced Light Source (ALS) andStanford Synchrotron Radiation Laboratory (SSRL) Users' Meeting inOctober of this year, the macromolecular crystallography staff at bothsynchrotrons held a joint hands-on workshop to address automation issuesin crystal mounting and data collection at the beamline. This paperdescribes the ALS portion of the workshop, while the accompanying paperreviews the SSRL workshop.

  18. Macromolecular Assemblage in the Design of a Synthetic AIDS Vaccine

    Science.gov (United States)

    Defoort, Jean-Philippe; Nardelli, Bernardetta; Huang, Wolin; Ho, David D.; Tam, James P.

    1992-05-01

    We describe a peptide vaccine model based on the mimicry of surface coat protein of a pathogen. This model used a macromolecular assemblage approach to amplify peptide antigens in liposomes or micelles. The key components of the model consisted of an oligomeric lysine scaffolding to amplify peptide antigens covalently 4-fold and a lipophilic membrane-anchoring group to further amplify noncovalently the antigens many-fold in liposomal or micellar form. A peptide antigen derived from the third variable domain of glycoprotein gp120 of human immunodeficiency virus type 1 (HIV-1), consisting of neutralizing, T-helper, and T-cytotoxic epitopes, was used in a macromolecular assemblage model (HIV-1 linear peptide amino acid sequence 308-331 in a tetravalent multiple antigen peptide system linked to tripalmitoyl-S-glycerylcysteine). The latter complex, in liposome or micelle, was used to immunize mice and guinea pigs without any adjuvant and found to induce gp120-specific antibodies that neutralize virus infectivity in vitro, elicit cytokine production, and prime CD8^+ cytotoxic T lymphocytes in vivo. Our results show that the macromolecular assemblage approach bears immunological mimicry of the gp120 of HIV virus and may lead to useful vaccines against HIV infection.

  19. REFMAC5 for the refinement of macromolecular crystal structures

    Energy Technology Data Exchange (ETDEWEB)

    Murshudov, Garib N., E-mail: garib@ysbl.york.ac.uk [Structural Biology Laboratory, Department of Chemistry, University of York, Heslington, York YO10 5YW (United Kingdom); Skubák, Pavol [Biophysical Structural Chemistry, Leiden University, PO Box 9502, 2300 RA Leiden (Netherlands); Lebedev, Andrey A. [Structural Biology Laboratory, Department of Chemistry, University of York, Heslington, York YO10 5YW (United Kingdom); Pannu, Navraj S. [Biophysical Structural Chemistry, Leiden University, PO Box 9502, 2300 RA Leiden (Netherlands); Steiner, Roberto A. [Randall Division of Cell and Molecular Biophysics, New Hunt’s House, King’s College London, London (United Kingdom); Nicholls, Robert A. [Structural Biology Laboratory, Department of Chemistry, University of York, Heslington, York YO10 5YW (United Kingdom); Winn, Martyn D. [STFC Daresbury Laboratory, Warrington WA4 4AD (United Kingdom); Long, Fei; Vagin, Alexei A. [Structural Biology Laboratory, Department of Chemistry, University of York, Heslington, York YO10 5YW (United Kingdom)

    2011-04-01

    The general principles behind the macromolecular crystal structure refinement program REFMAC5 are described. This paper describes various components of the macromolecular crystallographic refinement program REFMAC5, which is distributed as part of the CCP4 suite. REFMAC5 utilizes different likelihood functions depending on the diffraction data employed (amplitudes or intensities), the presence of twinning and the availability of SAD/SIRAS experimental diffraction data. To ensure chemical and structural integrity of the refined model, REFMAC5 offers several classes of restraints and choices of model parameterization. Reliable models at resolutions at least as low as 4 Å can be achieved thanks to low-resolution refinement tools such as secondary-structure restraints, restraints to known homologous structures, automatic global and local NCS restraints, ‘jelly-body’ restraints and the use of novel long-range restraints on atomic displacement parameters (ADPs) based on the Kullback–Leibler divergence. REFMAC5 additionally offers TLS parameterization and, when high-resolution data are available, fast refinement of anisotropic ADPs. Refinement in the presence of twinning is performed in a fully automated fashion. REFMAC5 is a flexible and highly optimized refinement package that is ideally suited for refinement across the entire resolution spectrum encountered in macromolecular crystallography.

  20. Macromolecular amplification of binding response in superaptamer hydrogels.

    Science.gov (United States)

    Bai, Wei; Gariano, Nicholas A; Spivak, David A

    2013-05-08

    It is becoming more important to detect ultralow concentrations of analytes for biomedical, environmental, and national security applications. Equally important is that new methods should be easy to use, inexpensive, portable, and if possible allow detection by the naked eye. By and large, detection of low concentrations of analytes cannot be achieved directly but requires signal amplification by catalysts, macromolecules, metal surfaces, or supramolecular aggregates. The rapidly progressing field of macromolecular signal amplification has been advanced using conjugated polymers, chirality in polymers, solvating polymers, and polymerization/depolymerization strategies. A new type of aptamer-based hydrogel with specific response to target proteins presented in this report demonstrates an additional category of macromolecular signal amplification. This superaptamer assembly provides the first example of using protein-specific aptamers to create volume-changing hydrogels with amplified response to the target protein. A remarkable aspect of these superaptamer hydrogels is that volume shrinking is visible to the naked eye down to femtomolar concentrations of protein. This extraordinary macromolecular amplification is attributed to a complex interplay between protein-aptamer supramolecular cross-links and the consequential reduction of excluded volume in the hydrogel. Specific recognition is even maintained in biological matrices such as urine and tears. Furthermore, the gels can be dried for long-term storage and regenerated for use without loss of activity. In practice, the ease of this biomarker detection method offers an alternative to traditional analytical techniques that require sophisticated instrumentation and highly trained personnel.

  1. Calculation of Leakage Inductance for High Frequency Transformers

    DEFF Research Database (Denmark)

    Ouyang, Ziwei; Jun, Zhang; Hurley, William Gerard

    2015-01-01

    Frequency dependent leakage inductance is often observed. High frequency eddy current effects cause a reduction in leakage inductance. The proximity effect between adjacent layers is responsible for the reduction of leakage inductance. This paper gives a detailed analysis of high frequency leakage...

  2. Determination of leakage areas in nuclear piping

    Energy Technology Data Exchange (ETDEWEB)

    Keim, E. [Siemens/KWU, Erlangen (Germany)

    1997-04-01

    For the design and operation of nuclear power plants the Leak-Before-Break (LBB) behavior of a piping component has to be shown. This means that the length of a crack resulting in a leak is smaller than the critical crack length and that the leak is safely detectable by a suitable monitoring system. The LBB-concept of Siemens/KWU is based on computer codes for the evaluation of critical crack lengths, crack openings, leakage areas and leakage rates, developed by Siemens/KWU. In the experience with the leak rate program is described while this paper deals with the computation of crack openings and leakage areas of longitudinal and circumferential cracks by means of fracture mechanics. The leakage areas are determined by the integration of the crack openings along the crack front, considering plasticity and geometrical effects. They are evaluated with respect to minimum values for the design of leak detection systems, and maximum values for controlling jet and reaction forces. By means of fracture mechanics LBB for subcritical cracks has to be shown and the calculation of leakage areas is the basis for quantitatively determining the discharge rate of leaking subcritical through-wall cracks. The analytical approach and its validation will be presented for two examples of complex structures. The first one is a pipe branch containing a circumferential crack and the second one is a pipe bend with a longitudinal crack.

  3. Analysis of Leakages and Leakage Reduction Methods in UDSM CMOS VLSI Circuits.

    Directory of Open Access Journals (Sweden)

    Sagar Ekade

    2014-04-01

    Full Text Available This is the era of portable devices which need to be powered by battery. Due to scarcity of space and leakages in chips, battery life is a serious concern. As technology advances, scaling of transistor feature size and supply voltage has improved the performance, increased the transistor density and reduced the power required by the chip. The maximum power consumed by the chip is the function of its technology along with its implementation. As technology is scaling down and CMOS circuits are supplied with lower supply voltages, the static power i.e. standby leakage current becomes very crucial. In Ultra Deep-submicron regime scaling has reduced the threshold voltage and that has led to increase in leakage current in sub-threshold region and hence rise in static power dissipation. This paper presents a critical analysis of leakages and leakage reduction techniques.

  4. Workshop on algorithms for macromolecular modeling. Final project report, June 1, 1994--May 31, 1995

    Energy Technology Data Exchange (ETDEWEB)

    Leimkuhler, B.; Hermans, J.; Skeel, R.D.

    1995-07-01

    A workshop was held on algorithms and parallel implementations for macromolecular dynamics, protein folding, and structural refinement. This document contains abstracts and brief reports from that workshop.

  5. Risk factors of pancreatic leakage after pancreaticoduodenectomy

    Institute of Scientific and Technical Information of China (English)

    Yin-Mo Yang; Xiao-Dong Tian; Yan Zhuang; Wei-Min Wang; Yuan-Lian Wan; Yan-Ting Huang

    2005-01-01

    AIM: To analyze the risk factors for pancreatic leakage after pancreaticoduodenectomy (PD) and to evaluate whether duct-to-mucosa pancreaticojejunostomy could reduce the risk of pancreatic leakage.METHODS: Sixty-two patients who underwent PD at our hospital between January 2000 and November 2003 were reviewed retrospectively. The primary diseases of the patients included pancreas cancer, ampullary cancer, bile duct cancer, islet cell cancer, duodenal cancer, chronic pancreatitis, pancreatic cystadenoma, and gastric cancer.Standard PD was performed for 25 cases, PD with extended lymphadenectomy for 27 cases, pylorus-preserving PD for 10 cases. A duct-to-mucosa pancreaticojejunostomy was performed for patients with a hard pancreas and a dilated pancreatic duct, and a traditional end-to-end invagination pancreaticojejunostomy for patients with a soft pancreas and a non-dilated duct. Patients were divided into two groups according to the incidence of postoperative pancreaticojejunal anastomotic leakage: 10 cases with leakage and 52 cases without leakage. Seven preoperative and six intraoperative risk factors with the potential to affect the incidence of pancreatic leakage were analyzed with SPSS10.0 software. Logistic regression was then used to determine the effect of multiple factors on pancreatic leakage.RESULTS: Of the 62 patients, 10 (16.13%) were identified as having pancreatic leakage after operation. Other major postoperative complications included delayed gastric emptying (eight patients), abdominal bleeding (four patients), abdominal abscess (three patients) and wound infection (two patients). The overall surgical morbidity was 43.5% (27/62). The hospital mortality in this series was 4.84% (3/62), and the mortality associated with pancreatic fistula was 10% (1/10). Sixteen cases underwent duct-to-mucosa pancreaticojejunostomy and 1 case (1/16, 6.25%) devel-oped postoperative pancreatic leakage, 46 cases underwent invagination pancreaticojejunostomy and 9

  6. Air leakage in residential solar heating systems

    Science.gov (United States)

    Shingleton, J. G.; Cassel, D. E.; Overton, R. L.

    1981-02-01

    A series of computer simulations was performed to evaluate the effects of component air leakage on system thermal performance for a typical residential solar heating system, located in Madison, Wisconsin. Auxiliary energy required to supplement solar energy for space heating was determined using the TRNSYS computer program, for a range of air leakage rates at the solar collector and pebble bed storage unit. The effects of heat transfer and mass transfer between the solar equipment room and the heated building were investigated. The effect of reduced air infiltration into the building due to pressurized by the solar air heating system were determined. A simple method of estimating the effect of collector array air leakage on system thermal performance was evaluated, using the f CHART method.

  7. Leakage current measurement in transformerless PV inverters

    DEFF Research Database (Denmark)

    Kerekes, Tamas; Sera, Dezso; Mathe, Laszlo

    2012-01-01

    to be used in commercial PV inverters for the measurement of leakage and fault ground currents. The German VDE0126–1–1 standard gives the limit for fault and leakage ground currents and all grid connected PV inverters have to comply with these limits and disconnect from the grid in case of a fault.......Photovoltaic (PV) installations have seen a huge increase during the last couple of years. Transformerless PV inverters are gaining more share of the total inverter market, due to their high conversion efficiency, small weight and size. Nevertheless safety should have an important role in case...... of these tranformerless systems, due to the missing galvanic isolation. Leakage and fault current measurement is a key issue for these inverter topologies to be able to comply with the required safety standards. This article presents the test results of two different current measurement sensors that were suggested...

  8. Survey on Techniques for Detecting Data Leakage

    Directory of Open Access Journals (Sweden)

    Bhosale Pranjali A

    2016-06-01

    Full Text Available In current business scenario, critical data is to be shared and transferred by organizations to many stake holders in order to complete particular task. The critical data include intellectual copyright, patient information etc. The activities like sharing and transferring of such critical data includes threats like leakage of information, misuse of data, illegal access to data and/or alteration of data. It is necessary to deal with such problem efficiently and effectively, popular solutions to this problem are use of firewalls, data loss prevention tools and watermarking. But sometimes culprit succeeds in overcoming such security measures hence, if organizations becomes able to find out the guilty client responsible for leakage of particular data then risk of data leakage is reduced. For this many systems are proposed, this paper includes information about techniques discussed in some of such methodologies.

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

    Directory of Open Access Journals (Sweden)

    Qian Ma

    Full Text Available BACKGROUND: 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. METHODOLOGY/PRINCIPAL FINDINGS: 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. CONCLUSIONS/SIGNIFICANCE: 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

  10. Quantifying information leakage of randomized protocols

    DEFF Research Database (Denmark)

    Biondi, Fabrizio; Legay, Axel; Malacaria, Pasquale

    2015-01-01

    The quantification of information leakage provides a quantitative evaluation of the security of a system. We propose the usage of Markovian processes to model deterministic and probabilistic systems. By using a methodology generalizing the lattice of information approach we model refined attackers...... capable to observe the internal behavior of the system, and quantify the information leakage of such systems. We also use our method to obtain an algorithm for the computation of channel capacity from our Markovian models. Finally, we show how to use the method to analyze timed and non-timed attacks...

  11. Quantifying information leakage of randomized protocols

    DEFF Research Database (Denmark)

    Biondi, Fabrizio; Legay, Axel; Malacaria, Pasquale;

    2015-01-01

    capable to observe the internal behavior of the system, and quantify the information leakage of such systems. We also use our method to obtain an algorithm for the computation of channel capacity from our Markovian models. Finally, we show how to use the method to analyze timed and non-timed attacks......The quantification of information leakage provides a quantitative evaluation of the security of a system. We propose the usage of Markovian processes to model deterministic and probabilistic systems. By using a methodology generalizing the lattice of information approach we model refined attackers...

  12. Quantifying Information Leakage of Randomized Protocols

    DEFF Research Database (Denmark)

    Biondi, Fabrizio; Wasowski, Andrzej; Legay, Axel;

    2013-01-01

    of information approach and is a natural framework for modeling refined attackers capable to observe the internal behavior of the system. We also use our method to obtain an algorithm for the computation of channel capacity from our Markovian models. Finally, we show how to use the method to analyze timed......The quantification of information leakage provides a quantitative evaluation of the security of a system. We propose the usage of Markovian processes to model and analyze the information leakage of deterministic and probabilistic systems. We show that this method generalizes the lattice...

  13. Inward Leakage in Tight-Fitting PAPRs

    Directory of Open Access Journals (Sweden)

    Frank C. Koh

    2011-01-01

    Full Text Available A combination of local flow measurement techniques and fog flow visualization was used to determine the inward leakage for two tight-fitting powered air-purifying respirators (PAPRs, the 3M Breathe-Easy PAPR and the SE 400 breathing demand PAPR. The PAPRs were mounted on a breathing machine head form, and flows were measured from the blower and into the breathing machine. Both respirators leaked a little at the beginning of inhalation, probably through their exhalation valves. In both cases, the leakage was not enough for fog to appear at the mouth of the head form.

  14. BLOOD FLOW AND MACROMOLECULAR TRANSPORT IN CURVED BLOOD VESSELS

    Institute of Scientific and Technical Information of China (English)

    WEI Lan; WEN Gong-bi; TAN Wen-chang

    2006-01-01

    A numerical analysis of the steady/pulsatile flow and macromolecular (such as LDL and Albumin) transport in curved blood vessels was carried out. The computational results predict that the vortex of the secondary flow is time-dependent in the aortic arch.The concentration of macromolecule concentrates at the region of sharp curve, and the wall concentration at the outer part is higher than that at the inner part. Atherosclerosis and thrombosis are prone to develop in such regions with sharp flow.

  15. Bringing macromolecular machinery to life using 3D animation.

    Science.gov (United States)

    Iwasa, Janet H

    2015-04-01

    Over the past decade, there has been a rapid rise in the use of three-dimensional (3D) animation to depict molecular and cellular processes. Much of the growth in molecular animation has been in the educational arena, but increasingly, 3D animation software is finding its way into research laboratories. In this review, I will discuss a number of ways in which 3d animation software can play a valuable role in visualizing and communicating macromolecular structures and dynamics. I will also consider the challenges of using animation tools within the research sphere.

  16. Radiation induced inter-device leakage degradation

    Institute of Scientific and Technical Information of China (English)

    胡志远; 刘张李; 邵华; 张正选; 宁冰旭; 陈明; 毕大炜; 邹世昌

    2011-01-01

    The evolution of inter-device leakage generation technologies is studied with an N-type current with total ionizing dose in transistors in 180 nm poly-gate field device (PFD) that uses the shallow trench isolation as an effective gate oxide. The overall r

  17. Protection of window glass from acoustic leakage

    OpenAIRE

    Lych, Sergij; Rakobovchuk, Volodymyr

    2013-01-01

    In a survey was presented an analysis of the most common glass samples on the Ukrainian market on their protection level against leakage of acoustic information. The glass samples were studied by means of roentgen analysis, and the impact of elemental composition of glass according to a laser beam reflection factor was defined.

  18. Macromolecular Crowding Enhances Thermal Stability of Rabbit Muscle Creatine Kinase

    Institute of Scientific and Technical Information of China (English)

    ZHU Jiang; HE Huawei; LI Sen

    2008-01-01

    The effect of dextran on the conformation (or secondary structure) and thermal stability of creatine kinase (CK) was studied using the far-ultraviolet (UV) circular dichroism (CD) spectra.The results showed that lower concentrations of dextran (less than 60 g/L) induced formation of the secondary CK structures.However,the secondary structure content of CK decreased when the dextran concentrations exceeded 60 g/L.Thermally induced transition curves were measured for CK in the presence of different concentrations of dextran by far-UV CD.The thermal transition curves were fitted to a two-state model by a nonlinear,least-squares method to obtain the transition temperature of the unfolding transition.An increase in the tran- sition temperature was observed with the increase of the dextran concentration.These observations qualita-tively accord with predictions of a previously proposed model for the effect of intermolecular excluded volume (macromolecular crowding) on protein stability and conformation.These findings imply that the effects of macromolecular crowding can have an important influence on our understanding of how protein folding oc-curs in vivo.

  19. Identifying and visualizing macromolecular flexibility in structural biology

    Directory of Open Access Journals (Sweden)

    Martina Palamini

    2016-09-01

    Full Text Available Structural biology comprises a variety of tools to obtain atomic resolution data for the investigation of macromolecules. Conventional structural methodologies including crystallography, NMR and electron microscopy often do not provide sufficient details concerning flexibility and dynamics, even though these aspects are critical for the physiological functions of the systems under investigation. However, the increasing complexity of the molecules studied by structural biology (including large macromolecular assemblies, integral membrane proteins, intrinsically disordered systems, and folding intermediates continuously demands in-depth analyses of the roles of flexibility and conformational specificity involved in interactions with ligands and inhibitors. The intrinsic difficulties in capturing often subtle but critical molecular motions in biological systems have restrained the investigation of flexible molecules into a small niche of structural biology. Introduction of massive technological developments over the recent years, which include time-resolved studies, solution X-ray scattering, and new detectors for cryo-electron microscopy, have pushed the limits of structural investigation of flexible systems far beyond traditional approaches of NMR analysis. By integrating these modern methods with powerful biophysical and computational approaches such as generation of ensembles of molecular models and selective particle picking in electron microscopy, more feasible investigations of dynamic systems are now possible. Using some prominent examples from recent literature, we review how current structural biology methods can contribute useful data to accurately visualize flexibility in macromolecular structures and understand its important roles in regulation of biological processes.

  20. MMDB and VAST+: tracking structural similarities between macromolecular complexes.

    Science.gov (United States)

    Madej, Thomas; Lanczycki, Christopher J; Zhang, Dachuan; Thiessen, Paul A; Geer, Renata C; Marchler-Bauer, Aron; Bryant, Stephen H

    2014-01-01

    The computational detection of similarities between protein 3D structures has become an indispensable tool for the detection of homologous relationships, the classification of protein families and functional inference. Consequently, numerous algorithms have been developed that facilitate structure comparison, including rapid searches against a steadily growing collection of protein structures. To this end, NCBI's Molecular Modeling Database (MMDB), which is based on the Protein Data Bank (PDB), maintains a comprehensive and up-to-date archive of protein structure similarities computed with the Vector Alignment Search Tool (VAST). These similarities have been recorded on the level of single proteins and protein domains, comprising in excess of 1.5 billion pairwise alignments. Here we present VAST+, an extension to the existing VAST service, which summarizes and presents structural similarity on the level of biological assemblies or macromolecular complexes. VAST+ simplifies structure neighboring results and shows, for macromolecular complexes tracked in MMDB, lists of similar complexes ranked by the extent of similarity. VAST+ replaces the previous VAST service as the default presentation of structure neighboring data in NCBI's Entrez query and retrieval system. MMDB and VAST+ can be accessed via http://www.ncbi.nlm.nih.gov/Structure.

  1. Enzymes as Green Catalysts for Precision Macromolecular Synthesis.

    Science.gov (United States)

    Shoda, Shin-ichiro; Uyama, Hiroshi; Kadokawa, Jun-ichi; Kimura, Shunsaku; Kobayashi, Shiro

    2016-02-24

    The present article comprehensively reviews the macromolecular synthesis using enzymes as catalysts. Among the six main classes of enzymes, the three classes, oxidoreductases, transferases, and hydrolases, have been employed as catalysts for the in vitro macromolecular synthesis and modification reactions. Appropriate design of reaction including monomer and enzyme catalyst produces macromolecules with precisely controlled structure, similarly as in vivo enzymatic reactions. The reaction controls the product structure with respect to substrate selectivity, chemo-selectivity, regio-selectivity, stereoselectivity, and choro-selectivity. Oxidoreductases catalyze various oxidation polymerizations of aromatic compounds as well as vinyl polymerizations. Transferases are effective catalysts for producing polysaccharide having a variety of structure and polyesters. Hydrolases catalyzing the bond-cleaving of macromolecules in vivo, catalyze the reverse reaction for bond forming in vitro to give various polysaccharides and functionalized polyesters. The enzymatic polymerizations allowed the first in vitro synthesis of natural polysaccharides having complicated structures like cellulose, amylose, xylan, chitin, hyaluronan, and chondroitin. These polymerizations are "green" with several respects; nontoxicity of enzyme, high catalyst efficiency, selective reactions under mild conditions using green solvents and renewable starting materials, and producing minimal byproducts. Thus, the enzymatic polymerization is desirable for the environment and contributes to "green polymer chemistry" for maintaining sustainable society.

  2. PRIGo: a new multi-axis goniometer for macromolecular crystallography

    Energy Technology Data Exchange (ETDEWEB)

    Waltersperger, Sandro; Olieric, Vincent, E-mail: vincent.olieric@psi.ch; Pradervand, Claude [Paul Scherrer Institute, Villigen PSI (Switzerland); Glettig, Wayne [Centre Suisse d’Electronique et Microtechnique SA, Neuchâtel 2002 (Switzerland); Salathe, Marco; Fuchs, Martin R.; Curtin, Adrian; Wang, Xiaoqiang; Ebner, Simon; Panepucci, Ezequiel; Weinert, Tobias [Paul Scherrer Institute, Villigen PSI (Switzerland); Schulze-Briese, Clemens [Dectris Ltd, Baden 5400 (Switzerland); Wang, Meitian, E-mail: vincent.olieric@psi.ch [Paul Scherrer Institute, Villigen PSI (Switzerland)

    2015-05-09

    The design and performance of the new multi-axis goniometer PRIGo developed at the Swiss Light Source at Paul Scherrer Institute is described. The Parallel Robotics Inspired Goniometer (PRIGo) is a novel compact and high-precision goniometer providing an alternative to (mini-)kappa, traditional three-circle goniometers and Eulerian cradles used for sample reorientation in macromolecular crystallography. Based on a combination of serial and parallel kinematics, PRIGo emulates an arc. It is mounted on an air-bearing stage for rotation around ω and consists of four linear positioners working synchronously to achieve x, y, z translations and χ rotation (0–90°), followed by a ϕ stage (0–360°) for rotation around the sample holder axis. Owing to the use of piezo linear positioners and active correction, PRIGo features spheres of confusion of <1 µm, <7 µm and <10 µm for ω, χ and ϕ, respectively, and is therefore very well suited for micro-crystallography. PRIGo enables optimal strategies for both native and experimental phasing crystallographic data collection. Herein, PRIGo hardware and software, its calibration, as well as applications in macromolecular crystallography are described.

  3. Critical review and perspective of macromolecularly imprinted polymers.

    Science.gov (United States)

    Kryscio, David R; Peppas, Nicholas A

    2012-02-01

    Molecular recognition is a fundamental and ubiquitous process that is the driving force behind life. Natural recognition elements - including antibodies, enzymes, nucleic acids, and cells - exploit non-covalent interactions to bind to their targets with exceptionally strong affinities. Due to this unparalleled proficiency, scientists have long sought to mimic natural recognition pathways. One promising approach is molecularly imprinted polymers (MIPs), which are fully synthetic systems formed via the crosslinking of organic polymers in the presence of a template molecule, which results in stereo-specific binding sites for this analyte of interest. Macromolecularly imprinted polymers, those synthesized in the presence of macromolecule templates (>1500 Da), are of particular importance because they open up the field for a whole new set of robust diagnostic tools. Although the specific recognition of small-molecular-weight analytes is now considered routine, extension of these efficacious procedures to the protein regime has, thus far, proved challenging. This paper reviews the main approaches employed, highlights studies of interest with an emphasis on recent work, and offers suggestions for future success in the field of macromolecularly imprinted polymers.

  4. Enhancing Endosomal Escape for Intracellular Delivery of Macromolecular Biologic Therapeutics.

    Science.gov (United States)

    Lönn, Peter; Kacsinta, Apollo D; Cui, Xian-Shu; Hamil, Alexander S; Kaulich, Manuel; Gogoi, Khirud; Dowdy, Steven F

    2016-09-08

    Bioactive macromolecular peptides and oligonucleotides have significant therapeutic potential. However, due to their size, they have no ability to enter the cytoplasm of cells. Peptide/Protein transduction domains (PTDs), also called cell-penetrating peptides (CPPs), can promote uptake of macromolecules via endocytosis. However, overcoming the rate-limiting step of endosomal escape into the cytoplasm remains a major challenge. Hydrophobic amino acid R groups are known to play a vital role in viral escape from endosomes. Here we utilize a real-time, quantitative live cell split-GFP fluorescence complementation phenotypic assay to systematically analyze and optimize a series of synthetic endosomal escape domains (EEDs). By conjugating EEDs to a TAT-PTD/CPP spilt-GFP peptide complementation assay, we were able to quantitatively measure endosomal escape into the cytoplasm of live cells via restoration of GFP fluorescence by intracellular molecular complementation. We found that EEDs containing two aromatic indole rings or one indole ring and two aromatic phenyl groups at a fixed distance of six polyethylene glycol (PEG) units from the TAT-PTD-cargo significantly enhanced cytoplasmic delivery in the absence of cytotoxicity. EEDs address the critical rate-limiting step of endosomal escape in delivery of macromolecular biologic peptide, protein and siRNA therapeutics into cells.

  5. Platelet function alterations in dengue are associated with plasma leakage

    NARCIS (Netherlands)

    Michels, M.; Alisjahbana, B.; Groot, P.G. de; Indrati, A.R.; Fijnheer, R.; Puspita, M.; Dewi, I.M.; Wijer, L. van de; Boer, E.M. de; Roest, M.; Ven, A.J. van der; Mast, Q. de

    2014-01-01

    Severe dengue is characterised by thrombocytopenia, plasma leakage and bleeding. Platelets are important for preservation of endothelial integrity. We hypothesised that platelet activation with secondary platelet dysfunction contribute to plasma leakage. In adult Indonesian patients with acute dengu

  6. Nonlinear Acoustics Used To Reduce Leakage Flow

    Science.gov (United States)

    Daniels, Christopher C.; Steinetz, Bruce M.

    2004-01-01

    Leakage and wear are two fundamental problems in all traditional turbine seals that contribute to an engine's inefficiency. The solutions to seal leakage and wear conflict in the conventional design space. Reducing the clearance between the seal and rotating shaft reduces leakage but increases wear because of increased contact incidents. Increasing the clearance to reduce the contact between parts reduces wear but increases parasitic leakage. The goal of this effort is to develop a seal that restricts leakage flow using acoustic pressure while operating in a noncontacting manner, thereby increasing life. In 1996, Dr. Timothy Lucas announced his discovery of a method to produce shock-free high-amplitude pressure waves. For the first time, the formation of large acoustic pressures was possible using dissonant resonators. A pre-prototype acoustic seal developed at the NASA Glenn Research Center exploits this fundamental acoustic discovery: a specially shaped cavity oscillated at the contained fluid's resonant frequency produces high-amplitude acoustic pressure waves of a magnitude approaching those required of today's seals. While the original researchers are continuing their development of acoustic pumps, refrigeration compressors, and electronic thermal management systems using this technology, the goal of researchers at Glenn is to apply these acoustic principles to a revolutionary sealing device. When the acoustic resonator shape is optimized for the sealing device, the flow from a high-pressure cavity to a low-pressure cavity will be restricted by a series of high-amplitude standing pressure waves of higher pressure than the pressure to be sealed. Since the sealing resonator cavity will not touch the adjacent sealing structures, seal wear will be eliminated, improving system life. Under a cooperative agreement between Glenn and the Ohio Aerospace Institute (OAI), an acoustic-based pre-prototype seal was demonstrated for the first time. A pressurized cavity was

  7. Leakage Current Estimation of CMOS Circuit with Stack Effect

    Institute of Scientific and Technical Information of China (English)

    Yong-Jun Xu; Zu-Ying Luo; Xiao-Wei Li; Li-Jian Li; Xian-Long Hong

    2004-01-01

    Leakage current of CMOS circuit increases dramatically with the technology scaling down and has become a critical issue of high performance system. Subthreshold, gate and reverse biased junction band-to-band tunneling (BTBT) leakages are considered three main determinants of total leakage current. Up to now, how to accurately estimate leakage current of large-scale circuits within endurable time remains unsolved, even though accurate leakage models have been widely discussed. In this paper, the authors first dip into the stack effect of CMOS technology and propose a new simple gate-level leakage current model. Then, a table-lookup based total leakage current simulator is built up according to the model. To validate the simulator, accurate leakage current is simulated at circuit level using popular simulator HSPICE for comparison. Some further studies such as maximum leakage current estimation, minimum leakage current generation and a high-level average leakage current macromodel are introduced in detail. Experiments on ISCAS85 and ISCAS89 benchmarks demonstrate that the two proposed leakage current estimation methods are very accurate and efficient.

  8. Techniques for Leakage Power Reduction in Nanoscale Circuits: A Survey

    DEFF Research Database (Denmark)

    Liu, Wei

    This report surveys progress in the field of designing low power especially low leakage CMOS circuits in deep submicron era. The leakage mechanism and various recently proposed run time leakage reduction techniques are presented. Two designs from Cadence and Sony respectively, which can represent...... current industrial application of these techniques, are also illustrated....

  9. Measurement Methods to Determine Air Leakage Between Adjacent Zones

    Energy Technology Data Exchange (ETDEWEB)

    Hult, Erin L. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Dickerhoff, Darryl J. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Price, Phillip N. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2012-09-01

    Air leakage between adjacent zones of a building can lead to indoor air quality and energy efficiency concerns, however there is no existing standard for measuring inter-zonal leakage. In this study, synthesized data and field measurements are analyzed in order to explore the uncertainty associated with different methods for collecting and analyzing fan pressurization measurements to calculate interzone leakage.

  10. 49 CFR 192.706 - Transmission lines: Leakage surveys.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Transmission lines: Leakage surveys. 192.706... Transmission lines: Leakage surveys. Leakage surveys of a transmission line must be conducted at intervals not exceeding 15 months, but at least once each calendar year. However, in the case of a transmission line...

  11. Macromolecular and dendrimer-based magnetic resonance contrast agents

    Energy Technology Data Exchange (ETDEWEB)

    Bumb, Ambika; Brechbiel, Martin W. (Radiation Oncology Branch, National Cancer Inst., National Inst. of Health, Bethesda, MD (United States)), e-mail: pchoyke@mail.nih.gov; Choyke, Peter (Molecular Imaging Program, National Cancer Inst., National Inst. of Health, Bethesda, MD (United States))

    2010-09-15

    Magnetic resonance imaging (MRI) is a powerful imaging modality that can provide an assessment of function or molecular expression in tandem with anatomic detail. Over the last 20-25 years, a number of gadolinium-based MR contrast agents have been developed to enhance signal by altering proton relaxation properties. This review explores a range of these agents from small molecule chelates, such as Gd-DTPA and Gd-DOTA, to macromolecular structures composed of albumin, polylysine, polysaccharides (dextran, inulin, starch), poly(ethylene glycol), copolymers of cystamine and cystine with GD-DTPA, and various dendritic structures based on polyamidoamine and polylysine (Gadomers). The synthesis, structure, biodistribution, and targeting of dendrimer-based MR contrast agents are also discussed

  12. Extracting trends from two decades of microgravity macromolecular crystallization history

    Science.gov (United States)

    Judge, Russell A.; Snell, Edward H.; van der Woerd, Mark J.

    2005-01-01

    Since the 1980s hundreds of macromolecular crystal growth experiments have been performed in the reduced acceleration environment of an orbiting spacecraft. Significant enhancements in structural knowledge have resulted from X-ray diffraction of the crystals grown. Similarly, many samples have shown no improvement or degradation in comparison to those grown on the ground. A complex series of interrelated factors affect these experiments and by building a comprehensive archive of the results it was aimed to identify factors that result in success and those that result in failure. Specifically, it was found that dedicated microgravity missions increase the chance of success when compared with those where crystallization took place as a parasitic aspect of the mission. It was also found that the chance of success could not be predicted based on any discernible property of the macromolecule available to us.

  13. An analysis of fractal geometry of macromolecular gelation

    Institute of Scientific and Technical Information of China (English)

    左榘; 陈天红; 冉少峰; 何炳林; 董宝中; 生文君; 杨恒林

    1996-01-01

    With fractal geometry theory and based on experiments, an analysis of fractal geometry behavior of gelation of macromolecules was carried out. Using the cross-linking copolymerization of styrene-divinylbenzene (DVB) as an example, through the determinations of the evolution of the molecular weight, size and the dependence of scattering intensity on the angle of macromolecules by employing laser and synchrotron small angle X-ray scattering, respectively, this chemical reaction was described quantitatively, its fractal behavior was analyzed and the fractal dimension was also measured. By avoiding the complex theories on gelation, this approach is based on modern physical techniques and theories to perform the analysis of the behavior of fractal geometry of macromolecular gelation and thus is able to reveal the rules of this kind of complicated gelation more essentially and profoundly.

  14. Macromolecular Crystallization with Microfluidic Free-Interface Diffusion

    Energy Technology Data Exchange (ETDEWEB)

    Segelke, B

    2005-02-24

    Fluidigm released the Topaz 1.96 and 4.96 crystallization chips in the fall of 2004. Topaz 1.96 and 4.96 are the latest evolution of Fluidigm's microfluidics crystallization technologies that enable ultra low volume rapid screening for macromolecular crystallization. Topaz 1.96 and 4.96 are similar to each other but represent a major redesign of the Topaz system and have of substantially improved ease of automation and ease of use, improved efficiency and even further reduced amount of material needed. With the release of the new Topaz system, Fluidigm continues to set the standard in low volume crystallization screening which is having an increasing impact in the field of structural genomics, and structural biology more generally. In to the future we are likely to see further optimization and increased utility of the Topaz crystallization system, but we are also likely to see further innovation and the emergence of competing technologies.

  15. Macromolecularly "Caged" Carbon Nanoparticles for Intracellular Trafficking via Switchable Photoluminescence.

    Science.gov (United States)

    Misra, Santosh K; Srivastava, Indrajit; Tripathi, Indu; Daza, Enrique; Ostadhossein, Fatemeh; Pan, Dipanjan

    2017-02-08

    Reversible switching of photoluminescence (PL) of carbon nanoparticles (CNP) can be achieved with counterionic macromolecular caging and decaging at the nanoscale. A negatively charged uncoated, "bare" CNP with high luminescence loses its PL when positively charged macromolecules are wrapped around its surface. Prepared caged carbons could regain their emission only through interaction with anionic surfactant molecules, representing anionic amphiphiles of endocytic membranes. This process could be verified by gel electrophoresis, spectroscopically and in vitro confocal imaging studies. Results indicated for the first time that luminescence switchable CNPs can be synthesized for efficient intracellular tracking. This study further supports the origin of photoluminescence in CNP as a surface phenomenon correlated a function of characteristic charged macromolecules.

  16. Large-volume protein crystal growth for neutron macromolecular crystallography.

    Science.gov (United States)

    Ng, Joseph D; Baird, James K; Coates, Leighton; Garcia-Ruiz, Juan M; Hodge, Teresa A; Huang, Sijay

    2015-04-01

    Neutron macromolecular crystallography (NMC) is the prevailing method for the accurate determination of the positions of H atoms in macromolecules. As neutron sources are becoming more available to general users, finding means to optimize the growth of protein crystals to sizes suitable for NMC is extremely important. Historically, much has been learned about growing crystals for X-ray diffraction. However, owing to new-generation synchrotron X-ray facilities and sensitive detectors, protein crystal sizes as small as in the nano-range have become adequate for structure determination, lessening the necessity to grow large crystals. Here, some of the approaches, techniques and considerations for the growth of crystals to significant dimensions that are now relevant to NMC are revisited. These include experimental strategies utilizing solubility diagrams, ripening effects, classical crystallization techniques, microgravity and theoretical considerations.

  17. In-vacuum long-wavelength macromolecular crystallography.

    Science.gov (United States)

    Wagner, Armin; Duman, Ramona; Henderson, Keith; Mykhaylyk, Vitaliy

    2016-03-01

    Structure solution based on the weak anomalous signal from native (protein and DNA) crystals is increasingly being attempted as part of synchrotron experiments. Maximizing the measurable anomalous signal by collecting diffraction data at longer wavelengths presents a series of technical challenges caused by the increased absorption of X-rays and larger diffraction angles. A new beamline at Diamond Light Source has been built specifically for collecting data at wavelengths beyond the capability of other synchrotron macromolecular crystallography beamlines. Here, the theoretical considerations in support of the long-wavelength beamline are outlined and the in-vacuum design of the endstation is discussed, as well as other hardware features aimed at enhancing the accuracy of the diffraction data. The first commissioning results, representing the first in-vacuum protein structure solution, demonstrate the promising potential of the beamline.

  18. On macromolecular refinement at subatomic resolution withinteratomic scatterers

    Energy Technology Data Exchange (ETDEWEB)

    Afonine, Pavel V.; Grosse-Kunstleve, Ralf W.; Adams, Paul D.; Lunin, Vladimir Y.; Urzhumtsev, Alexandre

    2007-11-09

    A study of the accurate electron density distribution in molecular crystals at subatomic resolution, better than {approx} 1.0 {angstrom}, requires more detailed models than those based on independent spherical atoms. A tool conventionally used in small-molecule crystallography is the multipolar model. Even at upper resolution limits of 0.8-1.0 {angstrom}, the number of experimental data is insufficient for the full multipolar model refinement. As an alternative, a simpler model composed of conventional independent spherical atoms augmented by additional scatterers to model bonding effects has been proposed. Refinement of these mixed models for several benchmark datasets gave results comparable in quality with results of multipolar refinement and superior of those for conventional models. Applications to several datasets of both small- and macro-molecules are shown. These refinements were performed using the general-purpose macromolecular refinement module phenix.refine of the PHENIX package.

  19. Revealing the macromolecular targets of complex natural products

    Science.gov (United States)

    Reker, Daniel; Perna, Anna M.; Rodrigues, Tiago; Schneider, Petra; Reutlinger, Michael; Mönch, Bettina; Koeberle, Andreas; Lamers, Christina; Gabler, Matthias; Steinmetz, Heinrich; Müller, Rolf; Schubert-Zsilavecz, Manfred; Werz, Oliver; Schneider, Gisbert

    2014-12-01

    Natural products have long been a source of useful biological activity for the development of new drugs. Their macromolecular targets are, however, largely unknown, which hampers rational drug design and optimization. Here we present the development and experimental validation of a computational method for the discovery of such targets. The technique does not require three-dimensional target models and may be applied to structurally complex natural products. The algorithm dissects the natural products into fragments and infers potential pharmacological targets by comparing the fragments to synthetic reference drugs with known targets. We demonstrate that this approach results in confident predictions. In a prospective validation, we show that fragments of the potent antitumour agent archazolid A, a macrolide from the myxobacterium Archangium gephyra, contain relevant information regarding its polypharmacology. Biochemical and biophysical evaluation confirmed the predictions. The results obtained corroborate the practical applicability of the computational approach to natural product ‘de-orphaning’.

  20. Identification of macromolecular complexes in cryoelectron tomograms of phantom cells

    Science.gov (United States)

    Frangakis, Achilleas S.; Böhm, Jochen; Förster, Friedrich; Nickell, Stephan; Nicastro, Daniela; Typke, Dieter; Hegerl, Reiner; Baumeister, Wolfgang

    2002-01-01

    Electron tomograms of intact frozen-hydrated cells are essentially three-dimensional images of the entire proteome of the cell, and they depict the whole network of macromolecular interactions. However, this information is not easily accessible because of the poor signal-to-noise ratio of the tomograms and the crowded nature of the cytoplasm. Here, we describe a template matching algorithm that is capable of detecting and identifying macromolecules in tomographic volumes in a fully automated manner. The algorithm is based on nonlinear cross correlation and incorporates elements of multivariate statistical analysis. Phantom cells, i.e., lipid vesicles filled with macromolecules, provide a realistic experimental scenario for an assessment of the fidelity of this approach. At the current resolution of ≈4 nm, macromolecules in the size range of 0.5–1 MDa can be identified with good fidelity. PMID:12391313

  1. 3DHZETRN: Neutron leakage in finite objects

    Science.gov (United States)

    Wilson, John W.; Slaba, Tony C.; Badavi, Francis F.; Reddell, Brandon D.; Bahadori, Amir A.

    2015-11-01

    The 3DHZETRN formalism was recently developed as an extension to HZETRN with an emphasis on 3D corrections for neutrons and light ions. Comparisons to Monte Carlo (MC) simulations were used to verify the 3DHZETRN methodology in slab and spherical geometry, and it was shown that 3DHZETRN agrees with MC codes to the degree that various MC codes agree among themselves. One limitation of such comparisons is that all of the codes (3DHZETRN and three MC codes) utilize different nuclear models/databases; additionally, using a common nuclear model is impractical due to the complexity of the software. It is therefore difficult to ascertain if observed discrepancies are caused by transport code approximations or nuclear model differences. In particular, an important simplification in the 3DHZETRN formalism assumes that neutron production cross sections can be represented as the sum of forward and isotropic components, where the forward component is subsequently solved within the straight-ahead approximation. In the present report, previous transport model results in specific geometries are combined with additional results in related geometries to study neutron leakage using the Webber 1956 solar particle event as a source boundary condition. A ratio is defined to quantify the fractional neutron leakage at a point in a finite object relative to a semi-infinite slab geometry. Using the leakage ratio removes some of the dependence on the magnitude of the neutron production and clarifies the effects of angular scattering and absorption with regard to differences between the models. Discussion is given regarding observed differences between the MC codes and conclusions drawn about the need for further code development. Although the current version of 3DHZETRN is reasonably accurate compared to MC simulations, this study shows that improved leakage estimates can be obtained by replacing the isotropic/straight-ahead approximation with more detailed descriptions.

  2. Alopecia associated with unexpected leakage from electron cone

    Energy Technology Data Exchange (ETDEWEB)

    Wen, B.C.; Pennington, E.C.; Hussey, D.H.; Jani, S.K.

    1989-06-01

    Excessive irradiation due to unexpected leakage was found on a patient receiving electron beam therapy. The cause of this leakage was analyzed and the amount of leakage was measured for different electron beam energies. The highest leakage occurred with a 6 x 6 cm cone using a 12 MeV electron beam. The leakage dose measured along the side of the cone could be as great as 40%. Until the cones are modified or redesigned, it is advised that all patient setups be carefully reviewed to assure that no significant patient areas are in the side scatter region.

  3. Project Boundary Setting and Leakage Treatment in CDM Project

    Institute of Scientific and Technical Information of China (English)

    ZOU Chen; WANG Shujuan; DUAN Maosheng; CHEN Changhe

    2005-01-01

    Project boundary setting and leakage treatment are two important issues to be considered when a clean development mechanism (CDM) project is being designed. There are still many uncertainties concerning these two issues. This paper reviews the concepts of project boundary setting and leakage in CDM projects, cites the types and sources of leakage, discusses the principles for determining leakage, and gives some proposed methods for dealing with leakage. A case study, using several steps to solve the boundary and leakage problems,shows how the analyzed principles and treatments can be implemented in a real project. Based on the result of the case study, the methods discussed are shown to be appropriate for settling leakage issues.

  4. Rationale for Measuring Duct Leakage Flows in Large Commercial Buildings

    Energy Technology Data Exchange (ETDEWEB)

    Wray, Craig P.; Diamond, Richard C.; Sherman, Max H.

    2005-07-01

    Industry-wide methods of assessing duct leakage are based on duct pressurization tests, and focus on ''high pressure'' ducts. Even though ''low pressure'' ducts can be a large fraction of the system and tend to be leaky, few guidelines or construction specifications require testing these ducts. We report here on the measured leakage flows from ten large commercial duct systems at operating conditions: three had low leakage (less than 5% of duct inlet flow), and seven had substantial leakage (9 to 26%). By comparing these flows with leakage flows estimated using the industry method, we show that the latter method by itself is not a reliable indicator of whole-system leakage flow, and that leakage flows need to be measured.

  5. Angiographic leakage of polypoidal choroidal vasculopathy on indocyanine angiography

    Institute of Scientific and Technical Information of China (English)

    ZUO Cheng-guo; WEN Feng; HUANG Shi-zhou; LUO Guang-wei; YAN Hong; WU Wei-ju; WU De-zheng

    2010-01-01

    Background There is no detailed report about the angiographic leakage of polypoidal choroidal vasculopathy (PCV)lesions on indocyanine green (ICG) angiography. This study aimed to investigate the angiographic leakage of polypoidal lesions in PCV on ICG angiography.Methods One hundred and forty-four eyes of 137 patients diagnosed as PCV were prospectively observed. Fundus examination, fluorescein angiography, and ICG angiography were performed. Leakage of polypoidal lesions and clinical features were recorded according to the angiograms.Results In all 144 eyes, 110 eyes showed angiographic leakage (leakage group) on ICG angiography and three subtypes of leakage group were noted, which were polypoidal dilations leakage (47 eyes, 42.7%), branching vascular networks leakage (14 eyes, 12.7%) and leakage of both (49 eyes, 44.5%). The other 34 eyes showed regression of polypoidal lesions (regression group). In leakage group, the rates of pigment epithelial detachment (PED), best corrected visual acuity (BCVA) <0.1 and old subretinal hemorrhages were 56.4% (62 eyes), 19.1% (21 eyes), and 4.6% (5 eyes)respectively, compared with 8.8% (3 eyes), 50% (17 eyes) and 38.2% (13 eyes) of regression group (P <0.001). The history of regression group was significantly longer (P <0.001).Conclusions Angiographic leakage and regression can be observed in PCV lesions. Leakage of both polypoidal dilations and branching vascular networks is the most common subtype in leakage group. PCV in leakage group is more likely to be related to PED, better BCVA and shorter history, while PCV regression group tends to relevant to old subretinal hemorrhage, worse BCVA and longer history. This may reflect that the former is active or in the early course while the later is resting or in the late phase of PCV.

  6. EVA Suit Microbial Leakage Investigation Project

    Science.gov (United States)

    Falker, Jay; Baker, Christopher; Clayton, Ronald; Rucker, Michelle

    2016-01-01

    The objective of this project is to collect microbial samples from various EVA suits to determine how much microbial contamination is typically released during simulated planetary exploration activities. Data will be released to the planetary protection and science communities, and advanced EVA system designers. In the best case scenario, we will discover that very little microbial contamination leaks from our current or prototype suit designs, in the worst case scenario, we will identify leak paths, learn more about what affects leakage--and we'll have a new, flight-certified swab tool for our EVA toolbox.

  7. NMR RELAXIVITY AND IMAGING OF NEUTRAL MACROMOLECULAR POLYESTER GADOLINIUM (Ⅲ) COMPLEXES

    Institute of Scientific and Technical Information of China (English)

    Kai-chao Yu; Hong-bing Hu; Mai-li Liu; Han-zhen Yuan; Chao-hui Ye; Ren-xi Zhuo

    1999-01-01

    Five neutral macromolecular polyester gadolinium (Ⅲ) complexes with pendant hydrophobic alkyl and aromatic functional groups were prepared. The longitudinal relaxation rates of these complexes were measured. One of these Gd (Ⅲ) complexes was chosen for the acute toxicity test and T1-weighted imaging measurement. Preliminary results showed that. compared with Gd-DTPA, the neutral macromolecular gadolinium (Ⅲ) complexes provide higher T1 relaxivity enhancement and longer function duration.

  8. A versatile microparticle-based immunoaggregation assay for macromolecular biomarker detection and quantification.

    Directory of Open Access Journals (Sweden)

    Haiyan Wu

    Full Text Available The rapid, sensitive and low-cost detection of macromolecular biomarkers is critical in clinical diagnostics, environmental monitoring, research, etc. Conventional assay methods usually require bulky, expensive and designated instruments and relative long assay time. For hospitals and laboratories that lack immediate access to analytical instruments, fast and low-cost assay methods for the detection of macromolecular biomarkers are urgently needed. In this work, we developed a versatile microparticle (MP-based immunoaggregation method for the detection and quantification of macromolecular biomarkers. Antibodies (Abs were firstly conjugated to MP through streptavidin-biotin interaction; the addition of macromolecular biomarkers caused the aggregation of Ab-MPs, which were subsequently detected by an optical microscope or optical particle sizer. The invisible nanometer-scale macromolecular biomarkers caused detectable change of micrometer-scale particle size distributions. Goat anti-rabbit immunoglobulin and human ferritin were used as model biomarkers to demonstrate MP-based immunoaggregation assay in PBS and 10% FBS to mimic real biomarker assay in the complex medium. It was found that both the number ratio and the volume ratio of Ab-MP aggregates caused by biomarker to all particles were directly correlated to the biomarker concentration. In addition, we found that the detection range could be tuned by adjusting the Ab-MP concentration. We envision that this novel MP-based immunoaggregation assay can be combined with multiple detection methods to detect and quantify macromolecular biomarkers at the nanogram per milliliter level.

  9. Macromolecular metallurgy of binary mesocrystals via designed multiblock terpolymers.

    Science.gov (United States)

    Xie, Nan; Liu, Meijiao; Deng, Hanlin; Li, Weihua; Qiu, Feng; Shi, An-Chang

    2014-02-26

    Self-assembling block copolymers provide access to the fabrication of various ordered phases. In particular, the ordered spherical phases can be used to engineer soft mesocrystals with domain size at the 5-100 nm scales. Simple block copolymers, such as diblock copolymers, form a limited number of mesocrystals. However multiblock copolymers are capable to form more complex mesocrystals. We demonstrate that designed B1AB2CB3 multiblock terpolymers, in which the A- and C-blocks form spherical domains and the packing of these spheres can be controlled by changing the lengths of the middle and terminal B-blocks, self-assemble into various binary mesocrystals with space group symmetries of a large number of binary ionic crystals, including NaCl, CsCl, ZnS, α-BN, AlB2, CaF2, TiO2, ReO3, Li3Bi, Nb3Sn(A15), and α-Al2O3. This approach can be generalized to other terpolymers as well as to tetrapolymers to obtain ternary mesocrystals. Our study provides a new concept of macromolecular metallurgy for producing crystal phases in a mesoscale and thus makes multiblock copolymers a robust platform for the engineering of functional materials.

  10. Macromolecular Powder Diffraction: Ready for genuine biological problems.

    Science.gov (United States)

    Karavassili, Fotini; Margiolaki, Irene

    2016-01-01

    Knowledge of 3D structures of biological molecules plays a major role in both understanding important processes of life and developing pharmaceuticals. Among several methods available for structure determination, macromolecular X-ray powder diffraction (XRPD) has transformed over the past decade from an impossible dream to a respectable method. XRPD can be employed in biosciences for various purposes such as observing phase transitions, characterizing bulk pharmaceuticals, determining structures via the molecular replacement method, detecting ligands in protein-ligand complexes, as well as combining micro-sized single crystal crystallographic data and powder diffraction data. Studies using synchrotron and laboratory sources in some standard configuration setups are reported in this review, including their respective advantages and disadvantages. Methods presented here provide an alternative, complementary set of tools to resolve structural problems. A variety of already existing software packages for powder diffraction data processing and analysis, some of which have been adapted to large unit cell studies, are briefly described. This review aims to provide necessary elements of theory and current methods, along with practical explanations, available software packages and highlighted case studies.

  11. Canadian macromolecular crystallography facility: a suite of fully automated beamlines.

    Science.gov (United States)

    Grochulski, Pawel; Fodje, Michel; Labiuk, Shaunivan; Gorin, James; Janzen, Kathryn; Berg, Russ

    2012-06-01

    The Canadian light source is a 2.9 GeV national synchrotron radiation facility located on the University of Saskatchewan campus in Saskatoon. The small-gap in-vacuum undulator illuminated beamline, 08ID-1, together with the bending magnet beamline, 08B1-1, constitute the Canadian Macromolecular Crystallography Facility (CMCF). The CMCF provides service to more than 50 Principal Investigators in Canada and the United States. Up to 25% of the beam time is devoted to commercial users and the general user program is guaranteed up to 55% of the useful beam time through a peer-review process. CMCF staff provides "Mail-In" crystallography service to users with the highest scored proposals. Both beamlines are equipped with very robust end-stations including on-axis visualization systems, Rayonix 300 CCD series detectors and Stanford-type robotic sample auto-mounters. MxDC, an in-house developed beamline control system, is integrated with a data processing module, AutoProcess, allowing full automation of data collection and data processing with minimal human intervention. Sample management and remote monitoring of experiments is enabled through interaction with a Laboratory Information Management System developed at the facility.

  12. Patch-clamp detection of macromolecular translocation along nuclear pores

    Directory of Open Access Journals (Sweden)

    Bustamante J.O.

    1998-01-01

    Full Text Available The present paper reviews the application of patch-clamp principles to the detection and measurement of macromolecular translocation along the nuclear pores. We demonstrate that the tight-seal 'gigaseal' between the pipette tip and the nuclear membrane is possible in the presence of fully operational nuclear pores. We show that the ability to form a gigaseal in nucleus-attached configurations does not mean that only the activity of channels from the outer membrane of the nuclear envelope can be detected. Instead, we show that, in the presence of fully operational nuclear pores, it is likely that the large-conductance ion channel activity recorded derives from the nuclear pores. We conclude the technical section with the suggestion that the best way to demonstrate that the nuclear pores are responsible for ion channel activity is by showing with fluorescence microscopy the nuclear translocation of ions and small molecules and the exclusion of the same from the cisterna enclosed by the two membranes of the envelope. Since transcription factors and mRNAs, two major groups of nuclear macromolecules, use nuclear pores to enter and exit the nucleus and play essential roles in the control of gene activity and expression, this review should be useful to cell and molecular biologists interested in understanding how patch-clamp can be used to quantitate the translocation of such macromolecules into and out of the nucleus

  13. Timely deposition of macromolecular structures is necessary for peer review

    Energy Technology Data Exchange (ETDEWEB)

    Joosten, Robbie P. [Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam (Netherlands); Soueidan, Hayssam; Wessels, Lodewyk F. A. [Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX, Amsterdam (Netherlands); Perrakis, Anastassis, E-mail: a.perrakis@nki.nl [Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam (Netherlands)

    2013-12-01

    Deposition of crystallographic structures should be concurrent with or prior to manuscript submission for peer review, enabling validation and increasing reliability of the PDB. Most of the macromolecular structures in the Protein Data Bank (PDB), which are used daily by thousands of educators and scientists alike, are determined by X-ray crystallography. It was examined whether the crystallographic models and data were deposited to the PDB at the same time as the publications that describe them were submitted for peer review. This condition is necessary to ensure pre-publication validation and the quality of the PDB public archive. It was found that a significant proportion of PDB entries were submitted to the PDB after peer review of the corresponding publication started, and many were only submitted after peer review had ended. It is argued that clear description of journal policies and effective policing is important for pre-publication validation, which is key in ensuring the quality of the PDB and of peer-reviewed literature.

  14. Synchrotron radiation macromolecular crystallography: science and spin-offs

    Directory of Open Access Journals (Sweden)

    John R. Helliwell

    2015-03-01

    Full Text Available A current overview of synchrotron radiation (SR in macromolecular crystallography (MX instrumentation, methods and applications is presented. Automation has been and remains a central development in the last decade, as have the rise of remote access and of industrial service provision. Results include a high number of Protein Data Bank depositions, with an increasing emphasis on the successful use of microcrystals. One future emphasis involves pushing the frontiers of using higher and lower photon energies. With the advent of X-ray free-electron lasers, closely linked to SR developments, the use of ever smaller samples such as nanocrystals, nanoclusters and single molecules is anticipated, as well as the opening up of femtosecond time-resolved diffraction structural studies. At SR sources, a very high-throughput assessment for the best crystal samples and the ability to tackle just a few micron and sub-micron crystals will become widespread. With higher speeds and larger detectors, diffraction data volumes are becoming long-term storage and archiving issues; the implications for today and the future are discussed. Together with the rise of the storage ring to its current pre-eminence in MX data provision, the growing tendency of central facility sites to offer other centralized facilities complementary to crystallography, such as cryo-electron microscopy and NMR, is a welcome development.

  15. JBluIce-EPICS control system for macromolecular crystallography.

    Energy Technology Data Exchange (ETDEWEB)

    Stepanov, S.; Makarov, O.; Hilgart, M.; Pothineni, S.; Urakhchin, A.; Devarapalli, S.; Yoder, D.; Becker, M.; Ogata, C.; Sanishvili, R.; Nagarajan, V.; Smith, J. L.; Fischetti, R. F. (Biosciences Division); (Univ. of Michigan)

    2011-01-01

    The trio of macromolecular crystallography beamlines constructed by the General Medicine and Cancer Institutes Collaborative Access Team (GM/CA-CAT) in Sector 23 of the Advanced Photon Source (APS) have been in growing demand owing to their outstanding beam quality and capacity to measure data from crystals of only a few micrometres in size. To take full advantage of the state-of-the-art mechanical and optical design of these beamlines, a significant effort has been devoted to designing fast, convenient, intuitive and robust beamline controls that could easily accommodate new beamline developments. The GM/CA-CAT beamline controls are based on the power of EPICS for distributed hardware control, the rich Java graphical user interface of Eclipse RCP and the task-oriented philosophy as well as the look and feel of the successful SSRL BluIce graphical user interface for crystallography. These beamline controls feature a minimum number of software layers, the wide use of plug-ins that can be written in any language and unified motion controls that allow on-the-fly scanning and optimization of any beamline component. This paper describes the ways in which BluIce was combined with EPICS and converted into the Java-based JBluIce, discusses the solutions aimed at streamlining and speeding up operations and gives an overview of the tools that are provided by this new open-source control system for facilitating crystallographic experiments, especially in the field of microcrystallography.

  16. New concepts and applications in the macromolecular chemistry of fullerenes.

    Science.gov (United States)

    Giacalone, Francesco; Martín, Nazario

    2010-10-08

    A new classification on the different types of fullerene-containing polymers is presented according to their different properties and applications they exhibit in a variety of fields. Because of their interest and novelty, water-soluble and biodegradable C(60)-polymers are discussed first, followed by polyfullerene-based membranes where unprecedented supramolecular structures are presented. Next are compounds that involve hybrid materials formed from fullerenes and other components such as silica, DNA, and carbon nanotubes (CNTs) where the most recent advances have been achieved. A most relevant topic is still that of C(60)-based donor-acceptor (D-A) polymers. Since their application in photovoltaics D-A polymers are among the most realistic applications of fullerenes in the so-called molecular electronics. The most relevant aspects in these covalently connected fullerene/polymer hybrids as well as new concepts to improve energy conversion efficiencies are presented.The last topics disccused relate to supramolecular aspects that are in involved in C(60)-polymer systems and in the self-assembly of C(60)-macromolecular structures, which open a new scenario for organizing, by means of non-covalent interactions, new supramolecular structures at the nano- and micrometric scale, in which the combination of the hydrofobicity of fullerenes with the versatility of the noncovalent chemistry afford new and spectacular superstructures.

  17. Residential Forced Air System Cabinet Leakage and Blower Performance

    Energy Technology Data Exchange (ETDEWEB)

    Walker, Iain S.; Dickerhoff, Darryl J.; Delp, William W.

    2010-03-01

    This project evaluated the air leakage and electric power consumption of Residential HVAC components, with a particular focus on air leakage of furnace cabinets. Laboratory testing of HVAC components indicated that air leakage can be significant and highly variable from unit to unit ? indicating the need for a standard test method and specifying maximum allowable air leakage in California State energy codes. To further this effort, this project provided technical assistance for the development of a national standard for Residential HVAC equipment air leakage. This standard is being developed by ASHRAE and is called"ASHRAE Standard 193P - Method of test for Determining the Air Leakage Rate of HVAC Equipment". The final part of this project evaluated techniques for measurement of furnace blower power consumption. A draft test procedure for power consumption was developed in collaboration with the Canadian General Standards Board: CSA 823"Performance Standard for air handlers in residential space conditioning systems".

  18. Transanal stent in anterior resection does not prevent anastomotic leakage

    DEFF Research Database (Denmark)

    Bülow, Steffen; Bulut, O; Christensen, Ib Jarle;

    2006-01-01

    OBJECTIVE: A defunctioning transanal stent may theoretically reduce the leakage rate after anterior rectal resection. We present a randomized open study with the aim of comparing the leakage rate after anterior resection with a loop ileostomy, a transanal stent, both or neither. PATIENTS....... On this basis it was decided to discontinue the study prematurely for ethical reasons. CONCLUSION: Decompression of the anastomosis with a transanal stent does not reduce the risk of anastomotic leakage after anterior resection....

  19. Influence of Slot Defect Length on Magnetic Flux Leakage

    Institute of Scientific and Technical Information of China (English)

    Songling HUANG; Luming LI; Haiqing YANG; Keren SHI

    2004-01-01

    A key issue, which influences the applications of magnetic flux leakage testing, is defect quantification. There have been many research on the relationship between width, depth and magnetic flux leakage of slot defect. However, the length factor is often ignored. The relationship between characteristics of defect leakage field and defect length was investigated. The magnetic flux leakages of a series of plate specimens with the same width, same depth and different length slot defects were tested under the same magnetizing conditions. Testing results show that defect length is an important parameter needed to consider in quantifying defects.

  20. Development of leakage monitoring system using radioisotopes

    Energy Technology Data Exchange (ETDEWEB)

    Lee, J. C.; Lee, D. S. [Seoil College, Seoul (Korea); Cho, Y. S. [Konyang University, Nonsan (Korea); Shin, S. K. [Sungkyunkwan Univ., Seoul (Korea)

    2000-04-01

    This study is to development the potable neutron back-scattering gauge for leakage and detecting liquid interface of an oil and liquid tank, using a radioisotopes. For this purpose, small sized, light weight potable gauge is to be designed as to develope neutron shielding mechanism, low power supply circuit, high voltage circuit, measurement circuit, and operating handle etc. The user will be able to set the duration of the time interval, the scale, the high voltage, the threshold, the channel window, the selection whether the data storage or not, the selection whether the scale, high voltage, threshold and window fix or not at any time. The counted pulse will be displayed with the numerical value and the line bar. The gauge will be able to connect to an IBM compatible PC via a serial port, power will be supplied by internal battery. 9 refs., 28 figs., 10 tabs. (Author)

  1. Leakages and pressure relations: an experimental research

    Directory of Open Access Journals (Sweden)

    F. De Paola

    2012-07-01

    Full Text Available Leaks in water systems are presently a frequent and increasing event that involves cost increase and poor service, not compliant to quality standards and modern management criteria. The most recent data available in Italy, resumed into the report issued by Control Committee for Water Resources Use (CONVIRI, shows leakages with an average value of 37%. It is important, for maintenance perspective, to investigate occurrence and evolution of water leaks and the analytical links between leaks Qp and network pressure P, for a reliable calibration of water networks quali-quantitative simulation models. The present work reports the results of an experimental campaign started at Laboratory of Hydraulic of Department of Hydraulic, Geotechnical and Environmental Engineering of University of Naples Federico II in order to analyze the features of Qp (P relation, which are compared with principal results issued in literature.

  2. Leakages and pressure relation: an experimental research

    Directory of Open Access Journals (Sweden)

    F. De Paola

    2012-11-01

    Full Text Available Leaks in water systems are presently a frequent and increasing event that involves cost increase and poor service, not compliant to quality standards and modern management criteria. The most recent data available in Italy, resumed into the report issued by Control Committee for Water Resources Use (CONVIRI, shows leakages with an average value of 37%. It is therefore important, for maintenance perspective, to investigate occurrence and evolution of water leaks and the analytical link between leaks Qp and network pressure P, for a reliable calibration of water networks quali-quantitative simulation models. The present work reports the first results of an experimental campaign started at Laboratory of Hydraulics of Department of Hydraulics, Geotechnical and Environmental Engineering of University of Naples Federico II in order to analyze the features of Qp(P relation, which are compared with other results issued in literature.

  3. Fluid leakage near the percolation threshold

    Science.gov (United States)

    Dapp, Wolf B.; Müser, Martin H.

    2016-02-01

    Percolation is a concept widely used in many fields of research and refers to the propagation of substances through porous media (e.g., coffee filtering), or the behaviour of complex networks (e.g., spreading of diseases). Percolation theory asserts that most percolative processes are universal, that is, the emergent powerlaws only depend on the general, statistical features of the macroscopic system, but not on specific details of the random realisation. In contrast, our computer simulations of the leakage through a seal—applying common assumptions of elasticity, contact mechanics, and fluid dynamics—show that the critical behaviour (how the flow ceases near the sealing point) solely depends on the microscopic details of the last constriction. It appears fundamentally impossible to accurately predict from statistical properties of the surfaces alone how strongly we have to tighten a water tap to make it stop dripping and also how it starts dripping once we loosen it again.

  4. DOMMINO 2.0: integrating structurally resolved protein-, RNA-, and DNA-mediated macromolecular interactions.

    Science.gov (United States)

    Kuang, Xingyan; Dhroso, Andi; Han, Jing Ginger; Shyu, Chi-Ren; Korkin, Dmitry

    2016-01-01

    Macromolecular interactions are formed between proteins, DNA and RNA molecules. Being a principle building block in macromolecular assemblies and pathways, the interactions underlie most of cellular functions. Malfunctioning of macromolecular interactions is also linked to a number of diseases. Structural knowledge of the macromolecular interaction allows one to understand the interaction's mechanism, determine its functional implications and characterize the effects of genetic variations, such as single nucleotide polymorphisms, on the interaction. Unfortunately, until now the interactions mediated by different types of macromolecules, e.g. protein-protein interactions or protein-DNA interactions, are collected into individual and unrelated structural databases. This presents a significant obstacle in the analysis of macromolecular interactions. For instance, the homogeneous structural interaction databases prevent scientists from studying structural interactions of different types but occurring in the same macromolecular complex. Here, we introduce DOMMINO 2.0, a structural Database Of Macro-Molecular INteractiOns. Compared to DOMMINO 1.0, a comprehensive database on protein-protein interactions, DOMMINO 2.0 includes the interactions between all three basic types of macromolecules extracted from PDB files. DOMMINO 2.0 is automatically updated on a weekly basis. It currently includes ∼1,040,000 interactions between two polypeptide subunits (e.g. domains, peptides, termini and interdomain linkers), ∼43,000 RNA-mediated interactions, and ∼12,000 DNA-mediated interactions. All protein structures in the database are annotated using SCOP and SUPERFAMILY family annotation. As a result, protein-mediated interactions involving protein domains, interdomain linkers, C- and N- termini, and peptides are identified. Our database provides an intuitive web interface, allowing one to investigate interactions at three different resolution levels: whole subunit network

  5. A Compact X-Ray System for Macromolecular Crystallography. 5

    Science.gov (United States)

    Gubarev, Mikhail; Ciszak, Ewa; Ponomarev, Igor; Joy, Marshall

    2000-01-01

    We describe the design and performance of a high flux x-ray system for macromolecular crystallography that combines a microfocus x-ray generator (40 gm FWHM spot size at a power level of 46.5Watts) and a 5.5 mm focal distance polycapillary optic. The Cu K(sub alpha) X-ray flux produced by this optimized system is 7.0 times above the X-ray flux previously reported. The X-ray flux from the microfocus system is also 3.2 times higher than that produced by the rotating anode generator equipped with a long focal distance graded multilayer monochromator (Green optic; CMF24-48-Cu6) and 30% less than that produced by the rotating anode generator with the newest design of graded multilayer monochromator (Blue optic; CMF12-38-Cu6). Both rotating anode generators operate at a power level of 5000 Watts, dissipating more than 100 times the power of our microfocus x-ray system. Diffraction data collected from small test crystals are of high quality. For example, 42,540 reflections collected at ambient temperature from a lysozyme crystal yielded R(sub sym) 5.0% for the data extending to 1.7A, and 4.8% for the complete set of data to 1.85A. The amplitudes of the reflections were used to calculate difference electron density maps that revealed positions of structurally important ions and water molecules in the crystal of lysozyme using the phases calculated from the protein model.

  6. A Compact X-Ray System for Macromolecular Crystallography

    Science.gov (United States)

    Gubarev, Mikhail; Ciszak, Ewa; Ponomarev, Igor; Gibson, Walter; Joy, Marshall

    2000-01-01

    We describe the design and performance of a high flux x-ray system for a macromolecular crystallography that combines a microfocus x-ray generator (40 micrometer full width at half maximum spot size at a power level of 46.5 W) and a collimating polycapillary optic. The Cu Ka lpha x-ray flux produced by this optimized system through a 500,um diam orifice is 7.0 times greater than the x-ray flux previously reported by Gubarev et al. [M. Gubarev et al., J. Appl. Crystallogr. 33, 882 (2000)]. The x-ray flux from the microfocus system is also 2.6 times higher than that produced by a rotating anode generator equipped with a graded multilayer monochromator (green optic, Osmic Inc. CMF24-48-Cu6) and 40% less than that produced by a rotating anode generator with the newest design of graded multilayer monochromator (blue optic, Osmic, Inc. CMF12-38-Cu6). Both rotating anode generators operate at a power level of 5000 W, dissipating more than 100 times the power of our microfocus x-ray system. Diffraction data collected from small test crystals are of high quality. For example, 42 540 reflections collected at ambient temperature from a lysozyme crystal yielded R(sub sym)=5.0% for data extending to 1.70 A, and 4.8% for the complete set of data to 1.85 A. The amplitudes of the observed reflections were used to calculate difference electron density maps that revealed positions of structurally important ions and water molecules in the crystal of lysozyme using the phases calculated from the protein model.

  7. A simple quantitative model of macromolecular crowding effects on protein folding: Application to the murine prion protein(121-231)

    Science.gov (United States)

    Bergasa-Caceres, Fernando; Rabitz, Herschel A.

    2013-06-01

    A model of protein folding kinetics is applied to study the effects of macromolecular crowding on protein folding rate and stability. Macromolecular crowding is found to promote a decrease of the entropic cost of folding of proteins that produces an increase of both the stability and the folding rate. The acceleration of the folding rate due to macromolecular crowding is shown to be a topology-dependent effect. The model is applied to the folding dynamics of the murine prion protein (121-231). The differential effect of macromolecular crowding as a function of protein topology suffices to make non-native configurations relatively more accessible.

  8. Theory and Practice of a Leakage Resilient Masking Scheme

    DEFF Research Database (Denmark)

    Balasch, Josep; Faust, Sebastian; Gierlichs, Benedikt

    2012-01-01

    A recent trend in cryptography is to formally prove the leakage resilience of cryptographic implementations – that is, one formally shows that a scheme remains provably secure even in the presence of side channel leakage. Although many of the proposed schemes are secure in a surprisingly strong m...

  9. Leakage-Resilient Cryptography from the Inner-Product Extractor

    DEFF Research Database (Denmark)

    Dziembowski, Stefan; Faust, Sebastian

    2011-01-01

    and encryption. More precisely, we propose efficient implementations of the Okamoto identification scheme, and of an ElGamal-based cryptosystem with security against continuous leakage, as long as the leakage adheres the above mentioned restrictions. We prove security of the Okamoto scheme under the DL...... assumption and CCA2 security of our encryption scheme under the DDH assumption....

  10. 75 FR 20546 - Total Inward Leakage Requirements for Respirators

    Science.gov (United States)

    2010-04-20

    ... HUMAN SERVICES 42 CFR Part 84 RIN 0920-AA33 Total Inward Leakage Requirements for Respirators AGENCY... Respirators,'' published in the Federal Register on October 30, 2009 (74 FR 56141). The comment period on this... total inward leakage (TIL) requirements for half-mask air-purifying particulate respirators approved...

  11. Detection of Macromolecular Fractions in HCN Polymers Using Electrophoretic and Ultrafiltration Techniques.

    Science.gov (United States)

    Marín-Yaseli, Margarita R; Cid, Cristina; Yagüe, Ana I; Ruiz-Bermejo, Marta

    2017-02-01

    Elucidating the origin of life involves synthetic as well as analytical challenges. Herein, for the first time, we describe the use of gel electrophoresis and ultrafiltration to fractionate HCN polymers. Since the first prebiotic synthesis of adenine by Oró, HCN polymers have gained much interest in studies on the origins of life due to the identification of biomonomers and related compounds within them. Here, we demonstrate that macromolecular fractions with electrophoretic mobility can also be detected within HCN polymers. The migration of polymers under the influence of an electric field depends not only on their sizes (one-dimensional electrophoresis) but also their different isoelectric points (two-dimensional electrophoresis, 2-DE). The same behaviour was observed for several macromolecular fractions detected in HCN polymers. Macromolecular fractions with apparent molecular weights as high as 250 kDa were detected by tricine-SDS gel electrophoresis. Cationic macromolecular fractions with apparent molecular weights as high as 140 kDa were also detected by 2-DE. The HCN polymers synthesized were fractionated by ultrafiltration. As a result, the molecular weight distributions of the macromolecular fractions detected in the HCN polymers directly depended on the synthetic conditions used to produce these polymers. The implications of these results for prebiotic chemistry will be discussed.

  12. Fifteen years of the Protein Crystallography Station: the coming of age of macromolecular neutron crystallography

    Directory of Open Access Journals (Sweden)

    Julian C.-H. Chen

    2017-01-01

    Full Text Available The Protein Crystallography Station (PCS, located at the Los Alamos Neutron Scattering Center (LANSCE, was the first macromolecular crystallography beamline to be built at a spallation neutron source. Following testing and commissioning, the PCS user program was funded by the Biology and Environmental Research program of the Department of Energy Office of Science (DOE-OBER for 13 years (2002–2014. The PCS remained the only dedicated macromolecular neutron crystallography station in North America until the construction and commissioning of the MaNDi and IMAGINE instruments at Oak Ridge National Laboratory, which started in 2012. The instrument produced a number of research and technical outcomes that have contributed to the field, clearly demonstrating the power of neutron crystallography in helping scientists to understand enzyme reaction mechanisms, hydrogen bonding and visualization of H-atom positions, which are critical to nearly all chemical reactions. During this period, neutron crystallography became a technique that increasingly gained traction, and became more integrated into macromolecular crystallography through software developments led by investigators at the PCS. This review highlights the contributions of the PCS to macromolecular neutron crystallography, and gives an overview of the history of neutron crystallography and the development of macromolecular neutron crystallography from the 1960s to the 1990s and onwards through the 2000s.

  13. Fifteen years of the Protein Crystallography Station: the coming of age of macromolecular neutron crystallography.

    Science.gov (United States)

    Chen, Julian C-H; Unkefer, Clifford J

    2017-01-01

    The Protein Crystallography Station (PCS), located at the Los Alamos Neutron Scattering Center (LANSCE), was the first macromolecular crystallography beamline to be built at a spallation neutron source. Following testing and commissioning, the PCS user program was funded by the Biology and Environmental Research program of the Department of Energy Office of Science (DOE-OBER) for 13 years (2002-2014). The PCS remained the only dedicated macromolecular neutron crystallography station in North America until the construction and commissioning of the MaNDi and IMAGINE instruments at Oak Ridge National Laboratory, which started in 2012. The instrument produced a number of research and technical outcomes that have contributed to the field, clearly demonstrating the power of neutron crystallo-graphy in helping scientists to understand enzyme reaction mechanisms, hydrogen bonding and visualization of H-atom positions, which are critical to nearly all chemical reactions. During this period, neutron crystallography became a technique that increasingly gained traction, and became more integrated into macromolecular crystallography through software developments led by investigators at the PCS. This review highlights the contributions of the PCS to macromolecular neutron crystallography, and gives an overview of the history of neutron crystallography and the development of macromolecular neutron crystallography from the 1960s to the 1990s and onwards through the 2000s.

  14. Zigbee Technology in Intelligent Electric Leakage Protection System Applied Research

    Directory of Open Access Journals (Sweden)

    Deng Lei-lei

    2013-08-01

    Full Text Available Aiming at inconvenient wiring and low flexibility of current wired sensor network,An implementation method for real-time monitoring system based on ZigBee wireless network is proposed in this paper. in view of existing selective earth leakage protection device of low sensitivity, poor reliability problems, proposed one kind based on the zero sequence current feature selectionSelective leakage protection and line selection method; analysis of power supply system leakage fault branch of zero-sequence current logical relations, introduced based on the zero sequence current featuresVolume selective leakage protection principle and the realization method of fault line selection.As a Zigbee wireless sensor technology, Its application to the grid. Analyze leakage protection system in relation to the past system of superior performance and favorable conditions, And its features and system design of a simple program to explain the analysis and application of specific measures.  

  15. Synthesis and characterization of miktoarm star copolymer of styrene and butadiene using multifunctional macromolecular initiator

    Institute of Scientific and Technical Information of China (English)

    Hai Yan Zhang; Xing Ying Zhang

    2009-01-01

    A new kind of multifunctional macromolecular initiator with Sn-C bonds and polydiene arms was synthesized by living anionic polymerization.At first,polydiene-stannum chloride(PD-SnCl3)was prepared by the reaction of n-butyl-Li(n-BuLi),stannic chloride(SnCl4)and diene.Then PD-SnCl3 was used to react with the dilithium initiator to prepare the multifunctional organic macromolecular initiators.The result suggested that the initiators had a remarkable yield by GPC,nearly 90%.By using these multifunctional macromolecular initiators,styrene and butadiene were effectively polymerized via anionic polymerization,which gave birth to novel miktoarm star copolymers.The relative molecular weight and polydispersity index,microstructure contents,copolymerization components,glass transition temperature(Tg)and morphology of the miktoarm star copolymers were investigated by GPC-UV,1H NMR,DSC and TEM,respectively.

  16. Use of Site-Specifically Tethered Chemical Nucleases to Study Macromolecular Reactions

    Directory of Open Access Journals (Sweden)

    Mukherjee Srabani

    2003-01-01

    Full Text Available During a complex macromolecular reaction multiple changes in molecular conformation and interactions with ligands may occur. X-ray crystallography may provide only a limited set of snapshots of these changes. Solution methods can augment such structural information to provide a more complete picture of a macromolecular reaction. We analyzed the changes in protein conformation and protein:nucleic acid interactions which occur during transcription initiation by using a chemical nuclease tethered to cysteines introduced site-specifically into the RNA polymerase of bacteriophage T7 (T7 RNAP. Changes in cleavage patterns as the polymerase steps through transcription reveal a series of structural transitions which mediate transcription initiation. Cleavage by tethered chemical nucleases is seen to be a powerful method for revealing the conformational dynamics of macromolecular reactions, and has certain advantages over cross-linking or energy transfer approaches.

  17. Macromolecular Hydrogen Sulfide Donors Trigger Spatiotemporally Confined Changes in Cell Signaling.

    Science.gov (United States)

    Ercole, Francesca; Mansfeld, Friederike M; Kavallaris, Maria; Whittaker, Michael R; Quinn, John F; Halls, Michelle L; Davis, Thomas P

    2016-01-11

    Hydrogen sulfide (H2S) is involved in a myriad of cell signaling processes that trigger physiological events ranging from vasodilation to cell proliferation. Moreover, disturbances to H2S signaling have been associated with numerous pathologies. As such, the ability to release H2S in a cellular environment and stimulate signaling events is of considerable interest. Herein we report the synthesis of macromolecular H2S donors capable of stimulating cell signaling pathways in both the cytosol and at the cell membrane. Specifically, copolymers having pendent oligo(ethylene glycol) and benzonitrile groups were synthesized, and the benzonitrile groups were subsequently transformed into primary aryl thioamide groups via thionation using sodium hydrosulfide. These thioamide moieties could be incorporated into a hydrophilic copolymer or a block copolymer (i.e., into either the hydrophilic or hydrophobic domain). An electrochemical sensor was used to demonstrate release of H2S under simulated physiological conditions. Subsequent treatment of HEK293 cells with a macromolecular H2S donor elicited a slow and sustained increase in cytosolic ERK signaling, as monitored using a FRET-based biosensor. The macromolecular donor was also shown to induce a small, fast and sustained increase in plasma membrane-localized PKC activity immediately following addition to cells. Studies using an H2S-selective fluorescent probe in live cells confirmed release of H2S from the macromolecular donor over physiologically relevant time scales consistent with the signaling observations. Taken together, these results demonstrate that by using macromolecular H2S donors it is possible to trigger spatiotemporally confined cell signaling events. Moreover, the localized nature of the observed signaling suggests that macromolecular donor design may provide an approach for selectively stimulating certain cellular biochemical pathways.

  18. Information Leakage Prevention Using Virtual Disk Drive

    Directory of Open Access Journals (Sweden)

    Tarek S. Sobh

    2013-06-01

    Full Text Available The worst news for information technology people are computer has been stolen or lost. The actual problem is the loss of the data stored on the hard drive that can fall into the wrong hands. However, users of information system and laptops computers are facing real problems with due to intruders using attack techniques when they are connected to the network and lost or stolen computers. In order to protect your organization against information leakage you should encrypt this data by only allowing the user with access to the encryption key to view the data, authorized application usage, and control who gets access to specific types of data. This work focuses on confidentiality of secure information storage. In addition, it presents the model to create of a Virtual Disk Drive (VDD on MS Windows, that appear to the user (after the mounting process as hard disks, but that are really stored as ciphered files on a file system. The proposed VDD prevents dictionary attacks and brute force attacks by incorporating a CAPTCHA (Completely Automated Public Turing test to tell Computers and Humans Apart in the login mechanism. The authentication method for the VDD login is based upon a 3-D image CAPTCHA. All components of this work are integrated in one security VDD tool called "SecDisk".

  19. The Joint Structural Biology Group beam lines at the ESRF: Modern macromolecular crystallography

    CERN Document Server

    Mitchell, E P

    2001-01-01

    Macromolecular crystallography has evolved considerably over the last decade. Data sets in under an hour are now possible on high throughput beam lines leading to electron density and, possibly, initial models calculated on-site. There are five beam lines currently dedicated to macromolecular crystallography: the ID14 complex and BM-14 (soon to be superseded by ID-29). These lines handle over five hundred projects every six months and demand is increasing. Automated sample handling, alignment and data management protocols will be required to work efficiently with this demanding load. Projects developing these themes are underway within the JSBG.

  20. Poly(isophthalic acid)(ethylene oxide) as a Macromolecular Modulator for Metal-Organic Polyhedra.

    Science.gov (United States)

    Chen, Teng-Hao; Wang, Le; Trueblood, Jonathan V; Grassian, Vicki H; Cohen, Seth M

    2016-08-03

    A new strategy was developed by using a polymer ligand, poly(isophthalic acid)(ethylene oxide), to modulate the growth of metal-organic polyhedra (MOP) crystals. This macromolecular modulator can effectively control the crystal habit of several different Cu24L24 (L = isophthalic acid derivatives) MOPs. The polymer also directed the formation of MOP structures under reaction conditions that only produce metal-organic frameworks in the absence of modulator. Moreover, the polymer also enabled the deposition of MOP crystals on glass surfaces. This macromolecular modulator strategy provides an innovative approach to control the morphology and assembly of MOP particles.

  1. Phase Sensitive X-Ray Diffraction Imaging of Defects in Biological Macromolecular Crystals

    Science.gov (United States)

    Hu, Z. W.; Lai, B.; Chu, Y. S.; Cai, Z.; Mancini, D. C.; Thomas, B. R.; Chernov, A. A.; Curreri, Peter A. (Technical Monitor)

    2002-01-01

    Characterization of defects and/or disorder in biological macromolecular crystals presents much greater challenges than in conventional small-molecule crystals. The lack of sufficient contrast of defects is often a limiting factor in x-ray diffraction topography of protein crystals. This has seriously hampered efforts to understand mechanisms and origins of formation of imperfections, and the role of defects as essential entities in the bulk of macromolecular crystals. In this report, we employ a phase sensitive x-ray diffraction imaging approach for augmenting the contrast of defects in protein crystals.

  2. Influence of protein crowder size on hydration structure and dynamics in macromolecular crowding

    Science.gov (United States)

    Wang, Po-hung; Yu, Isseki; Feig, Michael; Sugita, Yuji

    2017-03-01

    We investigate the effects of protein crowder sizes on hydration structure and dynamics in macromolecular crowded systems by all-atom MD simulations. The crowded systems consisting of only small proteins showed larger total surface areas than those of large proteins at the same volume fractions. As a result, more water molecules were trapped within the hydration shells, slowing down water diffusion. The simulation results suggest that the protein crowder size is another factor to determine the effect of macromolecular crowding and to explain the experimental kinetic data of proteins and DNAs in the presence of crowding agents.

  3. THE STEADY/PULSATILE FLOW AND MACROMOLECULAR TRANSPORT IN T-BIFURCATION BLOOD VESSELS

    Institute of Scientific and Technical Information of China (English)

    李丁; 温功碧

    2003-01-01

    A numerical analysis of the steady and pulsatile, macromolecular( such as lowdensity lipopotein ( LDL ), Albumin ) transport in T-bifurcation was proposed. Theinfluence of Reynolds number and mass flow ratio etc. parameters on the velocity field andmass transport were calculated. The computational results predict that the blood flow factorsaffect the macromolecular distribution and the transport across the wall, it shows thathemodynamic play an important role in the process of atherosclerosis . The LDL and Albuminconcentration on the wall varies most greatly in flow bifurcation area where the wall shearstress varies greatly at the branching vessel and the atherosclerosis often appears there.

  4. Accounting for large amplitude protein deformation during in silico macromolecular docking.

    Science.gov (United States)

    Bastard, Karine; Saladin, Adrien; Prévost, Chantal

    2011-02-22

    Rapid progress of theoretical methods and computer calculation resources has turned in silico methods into a conceivable tool to predict the 3D structure of macromolecular assemblages, starting from the structure of their separate elements. Still, some classes of complexes represent a real challenge for macromolecular docking methods. In these complexes, protein parts like loops or domains undergo large amplitude deformations upon association, thus remodeling the surface accessible to the partner protein or DNA. We discuss the problems linked with managing such rearrangements in docking methods and we review strategies that are presently being explored, as well as their limitations and success.

  5. Accounting for Large Amplitude Protein Deformation during in Silico Macromolecular Docking

    Directory of Open Access Journals (Sweden)

    Chantal Prévost

    2011-02-01

    Full Text Available Rapid progress of theoretical methods and computer calculation resources has turned in silico methods into a conceivable tool to predict the 3D structure of macromolecular assemblages, starting from the structure of their separate elements. Still, some classes of complexes represent a real challenge for macromolecular docking methods. In these complexes, protein parts like loops or domains undergo large amplitude deformations upon association, thus remodeling the surface accessible to the partner protein or DNA.We discuss the problems linked with managing such rearrangements in docking methods and we review strategies that are presently being explored, as well as their limitations and success.

  6. Effect of macromolecular crowding on the rate of diffusion-limited enzymatic reaction

    Indian Academy of Sciences (India)

    Manish Agrawal; S B Santra; Rajat Anand; Rajaram Swaminathan

    2008-08-01

    The cytoplasm of a living cell is crowded with several macromolecules of different shapes and sizes. Molecular diffusion in such a medium becomes anomalous due to the presence of macromolecules and diffusivity is expected to decrease with increase in macromolecular crowding. Moreover, many cellular processes are dependent on molecular diffusion in the cell cytosol. The enzymatic reaction rate has been shown to be affected by the presence of such macromolecules. A simple numerical model is proposed here based on percolation and diffusion in disordered systems to study the effect of macromolecular crowding on the enzymatic reaction rates. The model qualitatively explains some of the experimental observations.

  7. Novel Sleep Transistor Techniques for Low Leakage Power Peripheral Circuits

    Directory of Open Access Journals (Sweden)

    Rajani H.P

    2012-09-01

    Full Text Available Static power consumption is a major concern in nanometre technologies. Along with technology scaling down and higher operating speeds of CMOS VLSI circuits, the leakage power is getting enhanced. As process geometries are becoming smaller, device density increases and threshold voltage as well as oxide thickness decrease to keep pace with performance. Two novel circuit techniques for leakage current reduction in inverters with and without state retention property are presented in this work. The powerdissipation during inactive (standby mode of operation can be significantly reduced compared to traditional power gating methods by these circuit techniques. The proposed circuit techniques are applied to inverters and the results are compared with earlier inverter leakage minimization techniques. Inverter buffer chains are designed using new state retention low leakage technique and found to be dissipatinglower power with state retention. All low leakage inverters are designed and simulated in cadence design environment using 90 nm technology files. The leakage power during sleep mode is found to be better by X 63 times for novel method. The total power dissipation has also reduced by a factor of X 3.5, compared to earlier sleepy keeper technique. The state retention feature is also good compared to earlier leakage power reduction methodologies.

  8. Novel Sleep Transistor Techniques for Low Leakage Power Peripheral Circuits

    Directory of Open Access Journals (Sweden)

    Rajani H.P

    2012-08-01

    Full Text Available Static power consumption is a major concern in nanometre technologies. Along with technology scaling down and higher operating speeds of CMOS VLSI circuits, the leakage power is getting enhanced. As process geometries are becoming smaller, device density increases and threshold voltage as well as oxide thickness decrease to keep pace with performance. Two novel circuit techniques for leakage current reduction in inverters with and without state retention property are presented in this work. The power dissipation during inactive (standby mode of operation can be significantly reduced compared to traditional power gating methods by these circuit techniques. The proposed circuit techniques are applied to inverters and the results are compared with earlier inverter leakage minimization techniques. Inverter buffer chains are designed using new state retention low leakage technique and found to be dissipating lower power with state retention. All low leakage inverters are designed and simulated in cadence design environment using 90 nm technology files. The leakage power during sleep mode is found to be better by X 63 times for novel method. The total power dissipation has also reduced by a factor of X 3.5, compared to earlier sleepy keeper technique. The state retention feature is also good compared to earlier leakage power reduction methodologies.

  9. Developement of leakage localization technique by using acoustic signal

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Y. H.; Jeon, J. H.; Seo, D. H.; Kim, K. W. [KAIST, Daejeon (Korea, Republic of)

    2010-07-15

    The objective of this research is to develop a leakage monitoring system for pipelines or valves in the secondary water system of a nuclear power plant. The system aims to detect the existence of leakage and to estimate the leak location, especially by utilizing the noise generated from the leak. It is safe, precise real-time alert system compared with the previous monitoring methods and tools such as the visual test and the thermal imaging camera. When there exists leakage in the pipeline or valves of nuclear power plant, the noise due to gas flow is radiated through leak region. That is, the secondary water system with leakage generates different noise from the system without leakage. This motivates us to measure and analyze the noise generated from the secondary water system, so as firstly to detect the existence of leakage, and secondly to estimate the leak location by using the noise source identification technique such as beamforming and acoustic holography. Especially the beamforming method models the signal from the noise source to estimate the location of source. Therefore, it is necessary to model the noise due to leakage which is dependent upon parameters. In the process of leak localization, the reflected wave due to interior walls and the measurement noise should be removed for the precise estimation. Therefore, we attempt to characterize the reflected wave and the measurement noise by modeling the interior sound field, thus to remove them and to localize the leak location with high precision

  10. Junction leakage measurements with micro four-point probes

    DEFF Research Database (Denmark)

    Lin, Rong; Petersen, Dirch Hjorth; Wang, Fei;

    2012-01-01

    We present a new, preparation-free method for measuring the leakage current density on ultra-shallow junctions. The junction leakage is found by making a series of four-point sheet resistance measurements on blanket wafers with variable electrode spacings. The leakage current density is calculated...... using a fit of the measured four-point resistances to an analytical two-sheet model. The validity of the approximation involved in the two-sheet model is verified by a comparison to finite element model calculations....

  11. Transanal stent in anterior resection does not prevent anastomotic leakage

    DEFF Research Database (Denmark)

    Bülow, Steffen; Bulut, O; Christensen, Ib Jarle;

    2006-01-01

    OBJECTIVE: A defunctioning transanal stent may theoretically reduce the leakage rate after anterior rectal resection. We present a randomized open study with the aim of comparing the leakage rate after anterior resection with a loop ileostomy, a transanal stent, both or neither. PATIENTS...... completion of the operation the patients were randomized in two groups with and without a transanal stent. RESULTS: A clinically significant leakage was diagnosed in 25 patients (13%). No significant difference was found 17 of 98 patients with a stent and 8 of 96 without (P = 0.09), or in 9 of 44 ileostomy...... patients with a stent and in 3 of 45 without (P = 0.07). Several leaks over a short time led to an interim analysis after inclusion of 194 of 448 planned patients. The analysis showed no significant protective effect of the stent, and more leakages in the stent group, although not statistically significant...

  12. Reliable and efficient solution of genome-scale models of Metabolism and macromolecular Expression

    DEFF Research Database (Denmark)

    Ma, Ding; Yang, Laurence; Fleming, Ronan M. T.

    2017-01-01

    Constraint-Based Reconstruction and Analysis (COBRA) is currently the only methodology that permits integrated modeling of Metabolism and macromolecular Expression (ME) at genome-scale. Linear optimization computes steady-state flux solutions to ME models, but flux values are spread over many...

  13. Isolation and chemical characterization of resistant macromolecular constituents in microalgae and marine sediments

    NARCIS (Netherlands)

    Gelin, F.

    1996-01-01

    The recognition of novel, insoluble and non-hydrolysable macromolecular constituents in protective tissues of fresh-water algae and higher plants has had a major impact on our understanding of the origin and fate of sedimentary organic matter (OM) in terrestrial and lacustrine deposits. The investig

  14. Interplay between the bacterial nucleoid protein H-NS and macromolecular crowding in compacting DNA

    NARCIS (Netherlands)

    Wintraecken, C.H.J.M.

    2012-01-01

      In this dissertation we discuss H-NS and its connection to nucleoid compaction and organization. Nucleoid formation involves a dramatic reduction in coil volume of the genomic DNA. Four factors are thought to influence coil volume: supercoiling, DNA charge neutralization, macromolecular crow

  15. A kinetic type extended model for dense gases and macromolecular fluids

    Directory of Open Access Journals (Sweden)

    M. Cristina Carrisi

    2005-05-01

    Full Text Available Extended thermodynamics is an important theory which is appreciated from mathematicians and physicists. Following its ideas and considering the macroscopic approach with suggestions from the kinetic one, we find in this paper, the solution of an interesting model: the model for dense gases and macromolecular fluids.

  16. Macromolecular Crowding Modulates Folding Mechanism of α/β Protein Apoflavodoxin

    Science.gov (United States)

    Homouz, D.; Stagg, L.; Wittungstafshede, P.; Cheung, M.

    2009-01-01

    Protein dynamics in cells may be different from that in dilute solutions in vitro since the environment in cells is highly concentrated with other macromolecules. This volume exclusion due to macromolecular crowding is predicted to affect both equilibrium and kinetic processes involving protein conformational changes. To quantify macromolecular crowding effects on protein folding mechanisms, here we have investigated the folding energy landscape of an alpha/beta protein, apoflavodoxin, in the presence of inert macromolecular crowding agents using in silico and in vitro approaches. By coarse-grained molecular simulations and topology-based potential interactions, we probed the effects of increased volume fraction of crowding agents (phi_c) as well as of crowding agent geometry (sphere or spherocylinder) at high phi_c. Parallel kinetic folding experiments with purified Desulfovibro desulfuricans apoflavodoxin in vitro were performed in the presence of Ficoll (sphere) and Dextran (spherocylinder) synthetic crowding agents. In conclusion, we have identified in silico crowding conditions that best enhance protein stability and discovered that upon manipulation of the crowding conditions, folding routes experiencing topological frustrations can be either enhanced or relieved. The test-tube experiments confirmed that apoflavodoxin's time-resolved folding path is modulated by crowding agent geometry. We propose that macromolecular crowding effects may be a tool for manipulation of protein folding and function in living cells.

  17. Hydropyrolysis: A new technique for the analysis of macromolecular material in meteorites

    Science.gov (United States)

    Sephton, Mark A.; Love, Gordon D.; Meredith, Will; Snape, Colin E.; Sun, Cheng-Gong; Watson, Jonathan S.

    2005-10-01

    The carbonaceous chondrite meteorites are fragments of asteroids that have remained relatively unprocessed since the formation of the Solar System 4.56 billion years ago. The major organic component in these meteorites is a macromolecular phase that is resistant to solvent extraction. The information contained within macromolecular material can be accessed by degradative techniques such as pyrolysis. Hydropyrolysis refers to pyrolysis assisted by high hydrogen gas pressures and a dispersed sulphided molybdenum catalyst. Hydropyrolysis of the Murchison macromolecular material successfully releases much greater quantities of hydrocarbons than traditional pyrolysis techniques (twofold greater than hydrous pyrolysis) including significant amounts of high molecular weight polyaromatic hydrocarbons (PAH) such as phenanthrene, carbazole, fluoranthene, pyrene, chrysene, perylene, benzoperylene and coronene units with varying degrees of alkylation. When hydropyrolysis products are collected using a silica trap immersed in liquid nitrogen, the technique enables the solubilisation and retention of compounds with a wide range of volatilities (i.e. benzene to coronene). This report describes the hydropyrolysis method and the information it can provide about meteorite macromolecular material constitution.

  18. CHINA LEADS IN MAGNETIC FLUX LEAKAGE TECHNOLOGY IN THE WORLD

    Institute of Scientific and Technical Information of China (English)

    Yang Jinghan

    2005-01-01

    @@ High-resolution pipeline magnetic flux leakage tool with a diameter of 1,016 millimeters, a nondestructive detector developed corporately by Pipeline Technology Co. of China Oil & Gas Pipeline Bureau (CNPTC) and British Advantica (AT), has successfully passed pulling test in Langfang Test Center of Intellectual Pipeline Detector on July 2. This indicates that China's highresolution pipeline magnetic flux leakage technology has reached international advanced level.

  19. Leakage Power Reduction and Analysis of CMOS Sequential Circuits

    Directory of Open Access Journals (Sweden)

    M. Janaki Rani

    2012-02-01

    Full Text Available A significant portion of the total power consumption in high performance digital circuits in deep sub micron regime is mainly due to leakage power. Leakage is the only source of power consumption in an idle circuit. Therefore it is important to reduce leakage power in portable systems. In this paper two techniques such as transistor stacking and self-adjustable voltage level circuit for reducing leakage power in sequential circuits are proposed. This work analyses the power and delay of three different types of D flip-flops using pass transistors, transmission gates and gate diffusion input gates. . All the circuits are simulated with and without the application of leakage reduction techniques. Simulation results show that the proposed pass transistor based D flip-flop using self-adjustable voltage level circuit has the least leakage power dissipation of 9.13nW with a delay of 77 nS. The circuits are simulated with MOSFET models of level 54 using HSPICE in 90 nm process technology.

  20. Development of a new duct leakage test: DeltaQ

    Energy Technology Data Exchange (ETDEWEB)

    Walker,I.S.; Sherman,M.H.; Wempen, J.; Wang, D.; McWilliams, J.A.; Dickerhoff, D.J.

    2001-08-01

    Duct leakage is a key factor in determining energy losses from forced air heating and cooling systems. Several studies (Francisco and Palmiter 1997 and 1999, Andrews et al. 1998, and Siegel et al. 2001) have shown that the duct system efficiency cannot be reliably determined without good estimates of duct leakage. Specifically, for energy calculations, it is the duct leakage air flow to outside at operating conditions that is required. Existing test methods either precisely measure the size of leaks (but not the flow through them at operating conditions), or measure these flows with insufficient accuracy. The DeltaQ duct leakage test method was developed to provide improved estimates of duct leakage during system operation. In this study we developed the analytical calculation methods and the test procedures used in the DeltaQ test. As part of the development process, we have estimated uncertainties in the test method (both analytically and based on field data) and designed automated test procedures to increase accuracy and reduce the contributions of operator errors in performing field tests. In addition, the test has been evaluated in over 100 houses by several research teams to show that it can be used in a wide range of houses and to aid in finding limits or problems in field applications. The test procedure is currently being considered by ASTM as an update of an existing duct leakage standard.

  1. Reducing the leakage of body-worn incontinence pads.

    Science.gov (United States)

    Clancy, B; Malone-Lee, J

    1991-02-01

    The aim of this research was to evaluate the effect of various absorbent materials (fluff pulp and superabsorbent) on the leakage performance of incontinence pads. A shaped pad-and-pant system was used as the basic design and four pad types made to different specifications were compared using a double-blind technique. Forty-five elderly hospital residents who were incontinent of urine used all four pad types in a randomly allocated order. Data were recorded on more than 5000 pads over a 2-month period. Leakage was reduced by adding a second layer of fluff pulp and, whilst the addition of a superabsorbent material tended to reduce leakage further, we found no clear relationship between the amount of superabsorbent and the reduction of leakage. Other data indicated the importance of securing the pad in place with the appropriate net pants and the leakage rates of pads in relation to the amount of urine they contained. This research suggests that superabsorbent materials have great potential for reducing the leakage rate of incontinence pads but that the way in which they are incorporated into the pad, the amount of fluff pulp and the design of the pad also play an important part.

  2. Copper Ion as a New Leakage Tracer

    Directory of Open Access Journals (Sweden)

    Modaresi J.

    2013-12-01

    Full Text Available Statement of Problem: Most failures of root canal treatments are caused by bacteria. Studies showed that the most common cause of endodontic failures were the incomplete obturation of the root canal and the lack of adequate apical seal. Some in-vitro methods are used to estimate sealing quality, generally by measuring microleakage that allows the tracer agent to penetrate the filled canal.Purpose: Conventional methods of evaluating the seal of endodontically treated teeth are complicated and have some drawbacks. We used copper ion diffusion method to assess the leakage and the results were compared to dye penetration method.Materials and Method: The crowns of 21 extracted teeth were cut off at the CEJ level. After preparing the canals, the teeth were placed in tubes containing saline. They were divided randomly into 15 experimental cases; 3 positive and 3 negative controls. Positive controls were filled by single cone without sealer while the experimental and the negative control groups were filled by lateral technique. The coronal portion of gutta was removed and 9mm was left. The external surface of each tooth was coated with nail polish. Two millimeters of apical portion was immersed into 9ml of distilled water and 0.3ml of CuSO4 solution was injected into the coronal portion. After 2 days, copper sulfate was measured by an atomic absorption spectrophotometer. The teeth were then immersed in 2% methylene blue for 24 hours, sectioned and the extent of dye penetration was measured by a stereomicroscope.Results: The maximum and minimum recorded copper ion concentrations for the experimental group were 18.37 and 2.87ppm respectively. The maximum and minimum recorded dye penetrations for the experimental group were 8.5 and 3.5mm respectively. The statistical analysis, adopting paired samples test, showed poor correlation between average recorded results of two methods.Conclusion: Based on our results, there was no significant correlation between

  3. Multi-technique monitoring of CO2 leakage from an engineered CO2 leakage experiment

    Science.gov (United States)

    Zhou, X.; Apple, M. E.; Dobeck, L.; Cunningham, A. B.; Spangler, L.

    2012-12-01

    Monitoring of canopy and soil geophysical and geochemical properties in vadose zone by multiple techniques were carried out from 1999 to 2012 using an engineered CO2 release to simulate the CO2 leakage from CO2 storage at an agricultural plot at Bozeman, MT. The CO2 release was based on a horizontally-drilled well of 100 m at a depth of about 2.0-2.3m (Fig.1). Techniques utilized include hyperspectral and infrared radiation of various vegetations, electric conductivity in soil, magnetic field at the ground surface, and soil gas composition and dynamics using various gas sensors and soil moisture sensors. Measurements were made at several sites along a transect perpendicular to the releasing well, along which the soil CO2 concentration attenuated from high to normal condition at control site. The response of the canopy hyperspectral reflectance, infrared radiation, soil geophysical properties such as soil electric conductivity, top soil magnetic susceptibility and magnetic field, soil gas composition such as CO2 and O2 concentration to CO2 release at different rates were quantified and will be shown at this presentation. Fig.2 shows some examples of the results. The different responses at the impact and control sites are used to assess the effectiveness for CO2 surface and near-surface detection when a possible CO2 leakage occurs.ig.1. A schematic showing the injection and release of CO2 at an agricultral plot in Bozeman, MT. ig.2. Some examples of results showing the response of vegetation, hyperspectral reflectance, soil electric conductivity, soil O2 concentration to the release of CO2.

  4. Flexibility damps macromolecular crowding effects on protein folding dynamics: Application to the murine prion protein (121-231)

    Science.gov (United States)

    Bergasa-Caceres, Fernando; Rabitz, Herschel A.

    2014-01-01

    A model of protein folding kinetics is applied to study the combined effects of protein flexibility and macromolecular crowding on protein folding rate and stability. It is found that the increase in stability and folding rate promoted by macromolecular crowding is damped for proteins with highly flexible native structures. The model is applied to the folding dynamics of the murine prion protein (121-231). It is found that the high flexibility of the native isoform of the murine prion protein (121-231) reduces the effects of macromolecular crowding on its folding dynamics. The relevance of these findings for the pathogenic mechanism are discussed.

  5. Air-leakage effects on stone cladding panels

    Science.gov (United States)

    Colantonio, Antonio

    1995-03-01

    This paper looks at the effects of air leakage on insulated stone clad precast panels used in present day construction of large commercial buildings. The building investigated was a newly built twenty story office building in a high density urban setting. Air leakage was suspected as a possible cause for thermal comfort complaints at isolated locations within the perimeter zones of the building. During the warrantee period the building owner asked for a quality control inspection of the air barrier assembly of the building envelope. Infrared thermography was used to locate areas of suspected air leakage within the building envelope. In order to differentiate thermal patterns produced by air leakage, conduction and convection as well as radiation from external sources, the building was inspected from the exterior; (1) after being pressurized for three hours, (2) one hour after the building was depressurized and (3) two and a half hours after total building depressurization was maintained by the building mechanical systems. Thermal images from similar locations were correlated for each time and pressure setting to verify air leakage locations within the building envelope. Areas exhibiting air leakage were identified and contractors were requested to carry out the necessary repairs. The pressure differential across the building envelope needs to be known in order to properly carry out an inspection to identify all locations of air leakage within a building envelope. As well the direction of the air movement and the density of the cladding material need to be accounted for in the proper inspection of these types of wall assemblies.

  6. Suppression and control of leakage field in electromagnetic helical microwiggler

    Energy Technology Data Exchange (ETDEWEB)

    Ohigashi, N. [Kansai Univ., Osaka (Japan); Tsunawaki, Y. [Osaka Sangyo Univ. (Japan); Imasaki, K. [Institute for Laser Technology, Osaka (Japan)] [and others

    1995-12-31

    Shortening the period of electromagnetic wiggler introduces both the radical increase of the leakage field and the decrease of the field in the gap region. The leakage field is severer problem in planar electromagnetic wiggler than in helical wiggler. Hence, in order to develop a short period electromagnetic wiggler, we have adopted {open_quotes}three poles per period{close_quotes} type electromagnetic helical microwiggler. In this work, we inserted the permanent magnet (PM) blocks with specific magnetized directions in the space between magnetic poles, for suppressing the leakage field flowing out from a pole face to the neighboring pole face. These PM-blocks must have higher intrinsic coersive force than saturation field of pole material. The gap field due to each pole is adjustable by controlling the leakage fields, that is, controlling the position of each iron screw set in each retainer fixing the PM-blocks. At present time, a test wiggler with period 7.8mm, periodical number 10 and gap length 4.6mm has been manufactured. Because the ratio of PM-block aperture to gap length is important parameter to suppress the leakage field, the parameter has been surveyed experimentally for PM-blocks with several dimensions of aperture. The field strength of 3-5kG (K=0.2-0.4) would be expected in the wiggler.

  7. Effects of Geometry on Leakage Flow Characteristics of Brush Seal

    Institute of Scientific and Technical Information of China (English)

    Yuan Wei; Zhaobo Chen∗; Yinghou Jiao

    2015-01-01

    In order to better application of brush seal in rotating machinery, the leakage flow characteristics of the brush seal considering geometry effects are numerically analyzed using Reynolds⁃Averaged Navier⁃Stokes ( RANS) model coupling with a non⁃Darcian porous medium model. The reliability of the present numerical method is proved, which is in agreement with the experimental and numerical results from literatures. Three different bristle pack thicknesses, fence heights and initial clearances under different pressure ratios, rotational velocities and other operating conditions are utilized to investigate the effects of geometry modification on the brush seal leakage flow behaviors. It discusses the effectiveness of various geometry configurations outlining important flow features. The results indicate that the increase of fence height and clearance would lead to the increase of leakage rate. But the leakage is not linearly with respect to the bristle pack thickness, and the effect of rotational velocity is not obvious. Moreover, the detailed leakage flow fields and pressure distributions along the rotor surface, free bristle height, and fence height of the brush seals are also presented. The static pressure drop amplitude through the bristle pack and the pressure rise amplitude through the cavity would increase while the pressure differential increases. And the axial pressure is the main reason of bristle blow down. The results provide theoretical support for the brush seal structure optimal design.

  8. Radio frequency leakage current from unipolar laparoscopic electrocoagulators.

    Science.gov (United States)

    DiNovo, J A

    1983-09-01

    Radio frequency (RF) leakage current has been suspected of causing accidental tissue burns associated with laparoscopic electrocoagulation used for tubal sterilization. A study was done to determine the levels of capacitively coupled RF leakage current from six unipolar laparoscopes manufactured by five companies. Leakage current values ranging from less than 100 mA to over 550 mA were measured at electrosurgical unit power settings of up to 150 w into 1,000 ohms. These levels represent 24-62% of the total electrosurgical current generated by the electrosurgical units. Using a criterion for tissue injury of 100 mA/sq cm applied for ten seconds, leakage current levels exceeding 400 mA are capable of producing burns either at the abdominal wall or to internal organs that accidentally come into contact with the body of the laparoscope. One of the six devices tested had leakage current levels higher than 400 mA at power settings lower than 100 w. Capacitance measurements between the unipolar laparoscope body and the forceps ranged from 53 to 140 picofarads.

  9. Report on the water leakage from instrumentation pipe in JMTR

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2003-03-01

    On December 10, 2002, the leakage was found at the pressure instrumentation pipe attached to the exit pipe of No.1 charging pump of the purification system of a primary cooling system at JMTR in the Oarai Research establishment, JAERI. The Investigation Committee for Water Leakage from Instrumentation Pipe in JMTR was established and organized by specialists from inside and outside JAERI on December 16 and its meeting was held in public 3 times by 6th January, 2003. They found out the cause and countermeasures of cracks, and also investigated enhancement of safety management. As the result, it was considered that the leakage started around the 6th of December 2002 and the cause of the cracks was due to fatigue by vibration of the charging pump during operation. The committee discovered following incorrect actions in the safety management. First, operation of JMTR was continued without keeping careful watch in spite of occurrence of leakage detector alarm. Second, every time when the alarm range for the reasons other than the leakage, appropriate investigation and countermeasure were not taken. Third, the manager in charge didn't have a fair understanding of the situation and didn't give an appropriate direction. This is the report on the cause and countermeasures of cracks and enhancement of safety management. (author)

  10. An Investigation of Tendon Corrosion-Inhibitor Leakage into Concrete

    Energy Technology Data Exchange (ETDEWEB)

    Costello, J.F.; Naus, D.J.; Oland, C.B.

    1999-07-05

    During inspections performed at US nuclear power plants several years ago, some of the prestressed concrete containment had experienced leakage of the tendon sheathing filler. A study was conducted to indicate the extent of the leakage into the concrete and its potential effects on concrete properties. Concrete core samples were obtained from the Trojan Nuclear Plant. Examination and testing of the core samples indicated that the appearance of tendon sheathing filler on the surface was due to leakage of the filler from the conduits and its subsequent migration to the concrete surface through cracks that were present. Migration of the tendon sheathing filler was confined to the cracks with no perceptible movement into the concrete. Results of compressive strength tests indicated that the concrete quality was consistent in the containment and that the strength had increased relative to the strength at 28 days age.

  11. Leakage radiation microscope for observation of non-transparent samples.

    Science.gov (United States)

    Merlo, Juan M; Ye, Fan; Burns, Michael J; Naughton, Michael J

    2014-09-22

    We describe a leakage radiation microscope technique that can be used to extend the leakage radiation microscopy to optically non-transparent samples. In particular, two experiments are presented, first to demonstrate that acquired images with our configuration correspond to the leakage radiation phenomenon and second, to show possible applications by directly imaging a plasmonic structure that previously could only be imaged with a near-field scanning optical microscope. It is shown that the measured surface plasmon wavelength and propagation length agree with theoretically-calculated values. This configuration opens the possibility to study important effects where samples are optically non-transparent, as in plasmonic cavities and single hole plasmonic excitation, without the use of time-consuming near-field scanning optical microscopy.

  12. Understanding Instrumental Stokes Leakage in Murchison Widefield Array Polarimetry

    CERN Document Server

    Sutinjo, Adrian; Lenc, Emil; Wayth, Randall B; Padhi, Shantanu; Hall, Peter; Tingay, Steven J

    2014-01-01

    This paper offers an electromagnetic, more specifically array theory, perspective on understanding strong instrumental polarization effects for planar low-frequency "aperture arrays" with the Murchison Widefield Array (MWA) as an example. A long-standing issue that has been seen here is significant instrumental Stokes leakage after calibration, particularly in Stokes Q at high frequencies. A simple model that accounts for inter-element mutual coupling is presented which explains the prominence of Q leakage seen when the array is scanned away from zenith in the principal planes. On these planes, the model predicts current imbalance in the X (E-W) and Y (N-S) dipoles and hence the Q leakage. Although helpful in concept, we find that this model is inadequate to explain the full details of the observation data. This finding motivates further experimentation with more rigorous models that account for both mutual coupling and embedded element patterns. Two more rigorous models are discussed: the "full" and "average...

  13. Impact of the Indonesian throughflow on Agulhas leakage

    Directory of Open Access Journals (Sweden)

    D. Le Bars

    2013-02-01

    Full Text Available Using ocean models of different complexity we show that opening the Indonesian Passage between the Pacific and the Indian Ocean increases the input of Indian Ocean water into the South Atlantic via the Agulhas leakage. In a strongly eddying global ocean model this response results from an increased Agulhas Current transport and a constant proportion of Agulhas retroflection south of Africa. The leakage increases through an increased frequency of ring shedding events. In an idealized two-layer and flat-bottom eddy resolving model, the proportion of the Agulhas Current transport that retroflects is (for a wide range of wind stress forcing not affected by an opening of the Indonesian Passage. A linear ocean model is not able to explain this behavior which reveals the importance of mixed barotropic/baroclinic instabilities in controlling the Agulhas leakage.

  14. Air Leakage Rates in Typical Air Barrier Assemblies

    Energy Technology Data Exchange (ETDEWEB)

    Hun, Diana E. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Atchley, Jerald Allen [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Childs, Phillip W. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2016-11-01

    Estimates for 2010 indicate that infiltration in residential buildings was responsible for 2.85 quads of energy (DOE 2014), which is about 3% of the total energy consumed in the US. One of the mechanisms being implemented to reduce this energy penalty is the use of air barriers as part of the building envelope. These technologies decrease airflow through major leakage sites such as oriented strand board (OSB) joints, and gaps around penetrations (e.g., windows, doors, pipes, electrical outlets) as indicated by Hun et al. (2014). However, most air barrier materials do not properly address leakage spots such as wall-to-roof joints and wall-to-foundation joints because these are difficult to seal, and because air barrier manufacturers usually do not provide adequate instructions for these locations. The present study focuses on characterizing typical air leakage sites in wall assemblies with air barrier materials.

  15. Identifying and Managing Gas Leakage from Subsurface Sources

    Science.gov (United States)

    Benson, S. M.

    2015-12-01

    Subsurface gas accumulations exist from both natural sources such as hydrocarbon reservoirs, as well as, man-made sources such as natural gas storage, gas pipelines, CO2 storage, or even H2 storage. Both natural and manmade sources of subsurface gases have the potential to leak to the surface. Leakage can cause safety hazards and detrimental impacts associated with the release of greenhouse gases into the atmosphere. Leak management, which involves identifying, characterizing, assessing, and remediating leakage requires a coordinated and systematic approach to effectively deal with these occurrences. Here an overall workflow for leak management is presented, along with technological options and challenges for successful implementation. Many tools and approaches for leak management are available and in use today. However, the increased attention to leakage from a larger variety of sources, particularly associated with legacy facilities and infrastructure, raises new issues and challenges that are highlighted here.

  16. On the Connection between Leakage Tolerance and Adaptive Security

    DEFF Research Database (Denmark)

    Nielsen, Jesper Buus; Venturi, Daniele; Zottarel, Angela

    2013-01-01

    We revisit the context of leakage-tolerant interactive protocols as defined by Bitanski, Canetti and Halevi (TCC 2012). Our contributions can be summarized as follows: For the purpose of secure message transmission, any encryption protocol with message space M and secret key space SK tolerating...... at the end of the protocol execution, if and only if the protocol has passive adaptive security against an adaptive corruption of one party at the end of the protocol execution. This shows that as soon as a little leakage is tolerated, one needs full adaptive security. In case more than one party can...... be corrupted, we get that leakage tolerance is equivalent to a weaker form of adaptivity, which we call semi-adaptivity. Roughly, a protocol has semi-adaptive security if there exist a simulator which can simulate the internal state of corrupted parties, however, such a state is not required...

  17. Reducing water leakage into underground coal mines by aquifer dewatering

    Energy Technology Data Exchange (ETDEWEB)

    Schubert, J. P.

    1978-01-01

    Based on stratigraphic, structural, hydrogeologic, and mining data collected during a study in central Pennsylvania, a two-dimensional, finite-difference computer model was used to simulate groundwater flow in a sandstone unit (0.3 to 11 m thick) overlying an underground mine, and to evaluate the responses of the flow system and leakage rate into the mine when hypothetical dewatering wells are introduced into the system. Simulation of well dewatering, using 25 wells, showed that negligible reduction in leakage would occur if sandstone permeability was less than 0.30 m/day. When sandstone permeability equalled 3.0 m/day, 25 wells reduced leakage by 2.4 percent.

  18. Power Beaming Leakage Radiation as a SETI Observable

    CERN Document Server

    Benford, James N

    2016-01-01

    The most observable leakage radiation from an advanced civilization may well be from the use of power beaming to transfer energy and accelerate spacecraft. Applications suggested for power beaming involve Earth-to-space applications such as launching spacecraft to orbit, raising satellites to a higher orbit, and interplanetary concepts involving space-to-space transfers of cargo or passengers. We also quantify beam-driven launch to the outer solar system, interstellar precursors and ultimately starships. We estimate the principal observable parameters of power beaming leakage. Extraterrestrial civilizations would know their power beams could be observed, and so could put a message on the power beam and broadcast it for our receipt at little additional energy or cost. By observing leakage from power beams we may find a message embedded on the beam. Recent observations of the anomalous star KIC 8462852 by the Allen Telescope Array (ATA) set some limits on extraterrestrial power beaming in that system. We show t...

  19. Advances in electron microscopy: A qualitative view of instrumentation development for macromolecular imaging and tomography.

    Science.gov (United States)

    Schröder, Rasmus R

    2015-09-01

    Macromolecular imaging and tomography of ice embedded samples has developed into a mature imaging technology, in structural biology today widely referred to simply as cryo electron microscopy.(1) While the pioneers of the technique struggled with ill-suited instruments, state-of-the-art cryo microscopes are now readily available and an increasing number of groups are producing excellent high-resolution structural data of macromolecular complexes, of cellular organelles, or the morphology of whole cells. Instrumentation developers, however, are offering yet more novel electron optical devices, such as energy filters and monochromators, aberration correctors or physical phase plates. Here we discuss how current instrumentation has already changed cryo EM, and how newly available instrumentation - often developed in other fields of electron microscopy - may further develop the use and applicability of cryo EM to the imaging of single isolated macromolecules of smaller size or molecules embedded in a crowded cellular environment.

  20. Macromolecular crowding increases binding of DNA polymerase to DNA: an adaptive effect

    Energy Technology Data Exchange (ETDEWEB)

    Zimmerman, S.B.; Harrison, B.

    1987-05-01

    Macromolecular crowding extends the range of ionic conditions supporting high DNA polymerase reaction rates. Reactions tested were nick translation and gap-filling by DNA polymerase I of E. coli, nuclease and polymerase activities of the large fragment of that polymerase, and polymerization by the T4 DNA polymerase. For all of these reactions, high concentrations of nonspecific polymers increased enzymatic activity under otherwise inhibitory conditions resulting from relatively high ionic strength. The primary mechanism of the polymer effect seems to be to increase the binding of polymerase to DNA. They suggest that this effect of protein-DNA complexes is only one example of a general metabolic buffering action of crowded solutions on a variety of macromolecular interactions.

  1. 3DEM Loupe: Analysis of macromolecular dynamics using structures from electron microscopy.

    Science.gov (United States)

    Nogales-Cadenas, R; Jonic, S; Tama, F; Arteni, A A; Tabas-Madrid, D; Vázquez, M; Pascual-Montano, A; Sorzano, C O S

    2013-07-01

    Electron microscopy (EM) provides access to structural information of macromolecular complexes in the 3-20 Å resolution range. Normal mode analysis has been extensively used with atomic resolution structures and successfully applied to EM structures. The major application of normal modes is the identification of possible conformational changes in proteins. The analysis can throw light on the mechanism following ligand binding, protein-protein interactions, channel opening and other functional macromolecular movements. In this article, we present a new web server, 3DEM Loupe, which allows normal mode analysis of any uploaded EM volume using a user-friendly interface and an intuitive workflow. Results can be fully explored in 3D through animations and movies generated by the server. The application is freely available at http://3demloupe.cnb.csic.es.

  2. Romp: The Method of Choice for Precise Macromolecular Engineering and Synthesis of Smart Materials

    Science.gov (United States)

    Khosravi, Ezat; Castle, Thomas C.; Kujawa, Margaret; Leejarkpai, Jan; Hutchings, Lian R.; Hine, Peter J.

    The recent advances in olefin metathesis highlight the impact of Ring Opening Metathesis Polymerisation (ROMP) as a powerful technique for macromolecular engineering and synthesis of smart materials with well-defined structures. ROMP has attracted a considerable research attention recently particularly by industry largely due to the development of well-defined metal complexes as initiators and also because of the award of the Noble Prize for Chemistry in 2005 to three scientists (Chauvin, Grubbs, Schrock) for their contributions in this area. This chapter discusses several interesting examples in order to demonstrate that ROMP is a power tool in macromolecular engineering and that it allows the design and synthesis of polymers with novel topologies.

  3. The macromolecular crystallography beamline I911-3 at the MAX IV laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Ursby, Thomas, E-mail: thomas.ursby@maxlab.lu.se; Unge, Johan; Appio, Roberto [Lund University, POB 118, Lund SE-221 00 (Sweden); Logan, Derek T. [Lund University, POB 124, Lund SE-221 00 (Sweden); Fredslund, Folmer; Svensson, Christer; Larsson, Krister; Labrador, Ana [Lund University, POB 118, Lund SE-221 00 (Sweden); Thunnissen, Marjolein M. G. M. [Lund University, POB 124, Lund SE-221 00 (Sweden)

    2013-07-01

    The updated macromolecular crystallography beamline I911-3 at the MAX II storage ring is described. The macromolecular crystallography beamline I911-3, part of the Cassiopeia/I911 suite of beamlines, is based on a superconducting wiggler at the MAX II ring of the MAX IV Laboratory in Lund, Sweden. The beamline is energy-tunable within a range between 6 and 18 keV. I911-3 opened for users in 2005. In 2010–2011 the experimental station was completely rebuilt and refurbished such that it has become a state-of-the-art experimental station with better possibilities for rapid throughput, crystal screening and work with smaller samples. This paper describes the complete I911-3 beamline and how it is embedded in the Cassiopeia suite of beamlines.

  4. Optimal cytoplasmatic density and flux balance model under macromolecular crowding effects.

    Science.gov (United States)

    Vazquez, Alexei

    2010-05-21

    Macromolecules occupy between 34% and 44% of the cell cytoplasm, about half the maximum packing density of spheres in three dimension. Yet, there is no clear understanding of what is special about this value. To address this fundamental question we investigate the effect of macromolecular crowding on cell metabolism. We develop a cell scale flux balance model capturing the main features of cell metabolism at different nutrient uptakes and macromolecular densities. Using this model we show there are two metabolic regimes at low and high nutrient uptakes. The latter regime is characterized by an optimal cytoplasmatic density where the increase of reaction rates by confinement and the decrease by diffusion slow-down balance. More important, the predicted optimal density is in the range of the experimentally determined density of Escherichia coli.

  5. STUDIES ON PAN MACROMOLECULAR SEMICONDUCTING FIBER 1. PREPARATION OF PAN CONDUCTING FIBER TREATED BY STANNIC CHLORIDE AND ITS SEMICONDUCTING BEHAVIOUR

    Institute of Scientific and Technical Information of China (English)

    WANG Dexi; CUI Dayuan; LUO Boliang; WANG Xiugang; WU Renjie

    1984-01-01

    The PAN fiber treated by Lewis acid (e.g. stannic chloride) could be transformed into a macromolecular conducting fiber by further thermal treatment. Depending on thermal treatment condition the resistance of the fiber varied from 103 to 1012 Ω and kept stable after hydrolysis. The fiber has enough strength to be processed by various means. This is a new kind of macromolecular semiconducting fiber having some characteristics similar to those of organic semiconductors.

  6. On camera-based smoke and gas leakage detection

    Energy Technology Data Exchange (ETDEWEB)

    Nyboe, Hans Olav

    1999-07-01

    Gas detectors are found in almost every part of industry and in many homes as well. An offshore oil or gas platform may host several hundred gas detectors. The ability of the common point and open path gas detectors to detect leakages depends on their location relative to the location of a gas cloud. This thesis describes the development of a passive volume gas detector, that is, one than will detect a leakage anywhere in the area monitored. After the consideration of several detection techniques it was decided to use an ordinary monochrome camera as sensor. Because a gas leakage may perturb the index of refraction, parts of the background appear to be displaced from their true positions, and it is necessary to develop algorithms that can deal with small differences between images. The thesis develops two such algorithms. Many image regions can be defined and several feature values can be computed for each region. The value of the features depends on the pattern in the image regions. The classes studied in this work are: reference, gas, smoke and human activity. Test show that observation belonging to these classes can be classified fairly high accuracy. The features in the feature set were chosen and developed for this particular application. Basically, the features measure the magnitude of pixel differences, size of detected phenomena and image distortion. Interesting results from many experiments are presented. Most important, the experiments show that apparent motion caused by a gas leakage or heat convection can be detected by means of a monochrome camera. Small leakages of methane can be detected at a range of about four metres. Other gases, such as butane, where the densities differ more from the density of air than the density of methane does, can be detected further from the camera. Gas leakages large enough to cause condensation have been detected at a camera distance of 20 metres. 59 refs., 42 figs., 13 tabs.

  7. Cuffed Endotracheal Tube Size and Leakage in Pediatric Tracheal Models

    Directory of Open Access Journals (Sweden)

    Jun Hyun Kim

    2014-04-01

    Full Text Available Object: Cuffed endotracheal tubes are increasingly used in pediatric patients in the hope that they can reduce air leakage and tube size mismatch by just inflating the cuff. Authors compared influence of various tube sizes and different levels of cuff pressures to air leakage around the cuff, in artificial tracheal models. Methods: Six PVC cylinders of different internal diameters (ID: 8.15, 8.50, 9.70, 12.05, 14.50, and 20.00 mm were prepared. An artificial lung connected with cylinder was ventilated with an anesthesia machine. Cuffed endotracheal tubes of different sizes (ID 3.0~8.0 were located in the cylinders and the cuff was inflated with various pressures (15, 20, 25, 30 and 35 cm H2O. Expiratory tidal volume was measured with more than 25% loss of baseline expiratory tidal volume was considered significant air leakage. Results: Tube sizes same as, or larger than ID 5.0 didn’t show significant air leakage for any trachea model, only if the inflated cuff size is larger than the cylinder ID, except ID 5.5 tube at cuff pressure 15 cm H2O and 20 cm H2O, in 12.05 mm cylinder. Tubes sizes same as or smaller than ID 4.5, which have short cuff lengths and sizes than tubes larger than, or same as ID 5.0, leaked significantly at any tracheal models, except ID 4.5 tube at cuff pressure 35 cm H2O, in 8.50 mm cylinder. Conclusion: In PVC pediatric tracheal models, tubes same as, or smaller than ID 4.5 are inferior to tubes same as, or larger than ID 5.0 in preventing air leakage, and may need a higher cuff pressure to reduce air leakage. Further clinical studies could be designed based on our results.

  8. Controlling Macromolecular Topology with Genetically Encoded SpyTag-SpyCatcher Chemistry

    OpenAIRE

    Zhang, Wen-Bin; Sun, Fei; Tirrell, David A.; Arnold, Frances H.

    2013-01-01

    Control of molecular topology constitutes a fundamental challenge in macromolecular chemistry. Here we describe the synthesis and characterization of artificial elastin-like proteins (ELPs) with unconventional nonlinear topologies including circular, tadpole, star, and H-shaped proteins using genetically encoded SpyTag–SpyCatcher chemistry. SpyTag is a short polypeptide that binds its protein partner SpyCatcher and forms isopeptide bonds under physiological conditions. Sequences encoding SpyT...

  9. CplexA: a Mathematica package to study macromolecular-assembly control of gene expression

    OpenAIRE

    Vilar, J. M. G.; Saiz, L

    2010-01-01

    Summary: Macromolecular assembly vertebrates essential cellular processes, such as gene regulation and signal transduction. A major challenge for conventional computational methods to study these processes is tackling the exponential increase of the number of configurational states with the number of components. CplexA is a Mathematica package that uses functional programming to efficiently compute probabilities and average properties over such exponentially large number of states from the en...

  10. Porphyrin-Cored Polymer Nanoparticles: Macromolecular Models for Heme Iron Coordination.

    Science.gov (United States)

    Rodriguez, Kyle J; Hanlon, Ashley M; Lyon, Christopher K; Cole, Justin P; Tuten, Bryan T; Tooley, Christian A; Berda, Erik B; Pazicni, Samuel

    2016-10-03

    Porphyrin-cored polymer nanoparticles (PCPNs) were synthesized and characterized to investigate their utility as heme protein models. Created using collapsible heme-centered star polymers containing photodimerizable anthracene units, these systems afford model heme cofactors buried within hydrophobic, macromolecular environments. Spectroscopic interrogations demonstrate that PCPNs display redox and ligand-binding reactivity similar to that of native systems and thus are potential candidates for modeling biological heme iron coordination.

  11. STUDY ON HYDROLYSIS OF MACROMOLECULAR GELATIN WITH ENZYMES IN COMBINATION MODE

    Institute of Scientific and Technical Information of China (English)

    Ya-qin Huang; Rui Guan; Ming-zhi Huang

    2004-01-01

    The enzymatic hydrolysis of macromolecular gelatin with AS1.398 neutral protease, bromelain and their combinations was studied by estimating the molecular weights of their hydrolytic products. It was discovered that the products hydrolyzed by using combination enzymes had lower molecular weight than those obtained by using single ones,and the kind of enzymes, their combination mode and addition sequence are effective ways to control the molecular weights of gelatin hydrolyzates.

  12. Microvascular leakage of plasma proteins after PUVA and UVA

    Energy Technology Data Exchange (ETDEWEB)

    Staberg, B.; Worm, A.M.; Rossing, N.; Brodthagen, H.

    1982-04-01

    The transcapillary escape rate of albumin (TERalb), is a parameter of the leakage of macromolecules from the total microvasculature. In patients with psoriasis short-term PUVA treatment induces an increase in TERalb. In this study TERalb was measured in 3 groups of normal humans treated with PUVA, UVA and 8-methoxypsoralen. Treatment with PUVA and UVA caused a statistically significant increase in TERalb, whereas treatment with 8-methoxypsoralen did not induce any measurable changes. It is concluded that the UVA irradiation causes the abnormal leakage of macromolecules, whereas psoralen is not the responsible component. Furthermore the phenomenon can be elicited in normals and is not based on a preexisting psoriasis.

  13. Properties of Leakage Corrosion of Concrete and Its Durability

    Institute of Scientific and Technical Information of China (English)

    GE Xueliang; FANG Kunhe; ZENG Li; CHEN Xia

    2008-01-01

    The properties and mechanism of concrete under water leakage corrosion were studied in terms of the dissolution of calcium oxide and silicon oxide from concrete and the variation of pH value of permeate water.The experimental results show that the amount of calcium oxide and silicon oxide dissolved from per cubic meter of concrete gradually decrease with penetration time and ultimately stabilize at a certain value.The pH value of permeate water descend along with penetration time.The durability of concrete under leakage corrosion was analyzed by a formula fitted on the dissolved amount of calcium oxide.

  14. Principles and Overview of Sampling Methods for Modeling Macromolecular Structure and Dynamics.

    Directory of Open Access Journals (Sweden)

    Tatiana Maximova

    2016-04-01

    Full Text Available Investigation of macromolecular structure and dynamics is fundamental to understanding how macromolecules carry out their functions in the cell. Significant advances have been made toward this end in silico, with a growing number of computational methods proposed yearly to study and simulate various aspects of macromolecular structure and dynamics. This review aims to provide an overview of recent advances, focusing primarily on methods proposed for exploring the structure space of macromolecules in isolation and in assemblies for the purpose of characterizing equilibrium structure and dynamics. In addition to surveying recent applications that showcase current capabilities of computational methods, this review highlights state-of-the-art algorithmic techniques proposed to overcome challenges posed in silico by the disparate spatial and time scales accessed by dynamic macromolecules. This review is not meant to be exhaustive, as such an endeavor is impossible, but rather aims to balance breadth and depth of strategies for modeling macromolecular structure and dynamics for a broad audience of novices and experts.

  15. Protein crystallography for aspiring crystallographers or how to avoid pitfalls and traps in macromolecular structure determination.

    Science.gov (United States)

    Wlodawer, Alexander; Minor, Wladek; Dauter, Zbigniew; Jaskolski, Mariusz

    2013-11-01

    The number of macromolecular structures deposited in the Protein Data Bank now approaches 100,000, with the vast majority of them determined by crystallographic methods. Thousands of papers describing such structures have been published in the scientific literature, and 20 Nobel Prizes in chemistry or medicine have been awarded for discoveries based on macromolecular crystallography. New hardware and software tools have made crystallography appear to be an almost routine (but still far from being analytical) technique and many structures are now being determined by scientists with very limited experience in the practical aspects of the field. However, this apparent ease is sometimes illusory and proper procedures need to be followed to maintain high standards of structure quality. In addition, many noncrystallographers may have problems with the critical evaluation and interpretation of structural results published in the scientific literature. The present review provides an outline of the technical aspects of crystallography for less experienced practitioners, as well as information that might be useful for users of macromolecular structures, aiming to show them how to interpret (but not overinterpret) the information present in the coordinate files and in their description. A discussion of the extent of information that can be gleaned from the atomic coordinates of structures solved at different resolution is provided, as well as problems and pitfalls encountered in structure determination and interpretation.

  16. Macromolecular (pro)drugs with concurrent direct activity against the hepatitis C virus and inflammation.

    Science.gov (United States)

    Wohl, Benjamin M; Smith, Anton A A; Jensen, Bettina E B; Zelikin, Alexander N

    2014-12-28

    Macromolecular prodrugs (MPs) are a powerful tool to alleviate side-effects and improve the efficacy of the broad-spectrum antiviral agent ribavirin. In this work, we sought an understanding of what makes an optimal formulation within the macromolecular parameter space--nature of the polymer carrier, average molar mass, drug loading, or a good combination thereof. A panel of MPs based on biocompatible synthetic vinylic and (meth)acrylic polymers was tested in an anti-inflammatory assay with relevance to alleviating inflammation in the liver during hepatitis C infection. Pristine polymer carriers proved to have a pronounced anti-inflammatory activity, a notion which may prove significant in developing MPs for antiviral and anticancer treatments. With conjugated ribavirin, MPs revealed enhanced activity but also higher toxicity. Therapeutic windows and therapeutic indices were determined and discussed to reveal the most potent formulation and those with optimized safety. Polymers were also tested as inhibitors of replication of the hepatitis C viral RNA using a subgenomic viral replicon system. For the first time, negatively charged polymers are revealed to have an intracellular activity against hepatitis C virus replication. Concerted activity of the polymer and ribavirin afforded MPs which significantly increased the therapeutic index of ribavirin-based treatment. Taken together, the systematic investigation of the macromolecular space identified lead candidates with high efficacy and concurrent direct activity against the hepatitis C virus and inflammation.

  17. Osmotic Stressing, Membrane Leakage, and Fluorescence: An Introductory Biochemistry Demonstration

    Science.gov (United States)

    Seu, Kalani J.

    2015-01-01

    A fluorescence demonstration is described that incorporates several fundamental aspects of an introductory biochemistry course. A variation of a known leakage assay is utilized to prepare vesicles containing a quenched fluorophore. The vesicles are exposed to several osmotic environments ranging from isotonic to hypotonic. The degree of vesicle…

  18. Leakage of fluid in different types of tracheal tubes.

    Science.gov (United States)

    Winklmaier, U; Wüst, K; Schiller, S; Wallner, F

    2006-10-01

    The aim of this study was to evaluate leakage of liquids, i.e., water and saliva, past low-pressure cuffs of tracheostomy tubes. Three different types of tracheostomy tubes, TRACOE vario (TRACOE Medical GmbH, Germany), Rüsch Ultra-Tracheoflex (Rüsch GmbH, Germany), and Portex Blue Line Ultra (Smiths Medical, UK) were tested in isolated pig tracheas. Sixty samples (10 tubes each of 7- and 8-mm inner diameter of each type) were used. Four different experiments were devised: type 1 (water and artificial ventilation), type 2 (water and no artificial ventilation), type 3 (saliva and artificial ventilation), and type 4 (saliva and no artificial ventilation). Six milliliters of water or artificial saliva were infused over the cuff and the volume of fluid that leaked past the cuff was measured after 5, 10, and 15 min. Intracuff pressure was also measured three times. The saliva experiments resulted in less leakage than the water experiments. Leakage after treatment with water or artificial saliva is higher without artificial ventilation than with ventilation. The amount of leakage among the tubes with respect to manufacturer showed statistically significant results. However, there were no differences among tracheostomy tubes with respect to internal diameter.

  19. Leakage radiation spectroscopy of organic/dielectric/metal systems

    DEFF Research Database (Denmark)

    Fiutowski, Jacek; Kawalec, Tomasz; Kostiučenko, Oksana;

    2014-01-01

    Leakage radiation spectroscopy of organic para-Hexaphenylene (p-6P) molecules has been performed in the spectral range 420-675 nm which overlaps with the p-6P photoluminescence band. The p-6P was deposited on 40 nm silver (Ag) films on BK7 glass, covered with SiO2 layers. The SiO2 layer thickness...

  20. Blower-door techniques for measuring interzonal leakage

    Energy Technology Data Exchange (ETDEWEB)

    Hult, Erin L.; Sherman, Max H.; Walker, Iain

    2013-01-01

    Abstract The standard blower door test methods, such as ASTM E779, describe how to use a single blower door to determine the total leakage of a single-zone structure such as a detached single-family home. There are no standard test methods for measuring interzonal leakage in a two-zone or multi-zone building envelope such as might be encountered in with an attached garage or in a multifamily building. Some practitioners have been using techniques that involve making multiple measurements with a single blower door as well as combined measurements using multiple blower doors. Even for just two zones there are dozens of combinations of one-door and two-door test protocols that could conceivably be used to determine the interzonal air tightness. We examined many of these two-zone configurations using both simulation and measured data to estimate the accuracy and precision of each technique for realistic measurement scenarios. We also considered the impact of taking measurements at a single pressure versus over multiple pressures. We compared the various techniques and evaluated them for specific uses. Some techniques work better in one leakage regime; some are more sensitive to wind and other noise; some are more suited to determining only a subset of the leakage values. This paper makes recommendations on which techniques to use or not use for various cases and provides data that could be used to develop future test methods.

  1. Thresholds of information leakage for speech security outside meeting rooms.

    Science.gov (United States)

    Robinson, Matthew; Hopkins, Carl; Worrall, Ken; Jackson, Tim

    2014-09-01

    This paper describes an approach to provide speech security outside meeting rooms where a covert listener might attempt to extract confidential information. Decision-based experiments are used to establish a relationship between an objective measurement of the Speech Transmission Index (STI) and a subjective assessment relating to the threshold of information leakage. This threshold is defined for a specific percentage of English words that are identifiable with a maximum safe vocal effort (e.g., "normal" speech) used by the meeting participants. The results demonstrate that it is possible to quantify an offset that links STI with a specific threshold of information leakage which describes the percentage of words identified. The offsets for male talkers are shown to be approximately 10 dB larger than for female talkers. Hence for speech security it is possible to determine offsets for the threshold of information leakage using male talkers as the "worst case scenario." To define a suitable threshold of information leakage, the results show that a robust definition can be based upon 1%, 2%, or 5% of words identified. For these percentages, results are presented for offset values corresponding to different STI values in a range from 0.1 to 0.3.

  2. Characterization of CO2 leakage into the freshwater body

    DEFF Research Database (Denmark)

    Singh, Ashok; Delfs, Jens Olaf; Shao, H.

    2013-01-01

    urrent research into CO2 capture and storage is dominated by improving the CO2 storage capacity. In this context, risk related to CO2 leakage is an important issue which may cause environmental problems, particularly when freshwater resources nearby are intruded by the CO2 plume. In this work, th...

  3. 40 CFR 264.252 - Action leakage rate.

    Science.gov (United States)

    2010-07-01

    ... 264.252 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SOLID WASTES (CONTINUED) STANDARDS FOR OWNERS AND OPERATORS OF HAZARDOUS WASTE TREATMENT, STORAGE, AND DISPOSAL FACILITIES Waste... for waste pile units subject to § 264.251(c) or (d). The action leakage rate is the maximum...

  4. Leakage Currents and Gas Generation in Advanced Wet Tantalum Capacitors

    Science.gov (United States)

    Teverovsky, Alexander

    2015-01-01

    Currently, military grade, established reliability wet tantalum capacitors are among the most reliable parts used for space applications. This has been achieved over the years by extensive testing and improvements in design and materials. However, a rapid insertion of new types of advanced, high volumetric efficiency capacitors in space systems without proper testing and analysis of degradation mechanisms might increase risks of failures. The specifics of leakage currents in wet electrolytic capacitors is that the conduction process is associated with electrolysis of electrolyte and gas generation resulting in building up of internal gas pressure in the parts. The risk associated with excessive leakage currents and increased pressure is greater for high value advanced wet tantalum capacitors, but it has not been properly evaluated yet. In this work, in Part I, leakages currents in various types of tantalum capacitors have been analyzed in a wide range of voltages, temperatures, and time under bias. Gas generation and the level of internal pressure have been calculated in Part II for different case sizes and different hermeticity leak rates to assess maximal allowable leakage currents. Effects related to electrolyte penetration to the glass seal area have been studied and the possibility of failures analyzed in Part III. Recommendations for screening and qualification to reduce risks of failures have been suggested.

  5. Exploitation of Unintentional Information Leakage from Integrated Circuits

    Science.gov (United States)

    Cobb, William E.

    2011-01-01

    The information leakage of electronic devices, especially those used in cryptographic or other vital applications, represents a serious practical threat to secure systems. While physical implementation attacks have evolved rapidly over the last decade, relatively little work has been done to allow system designers to effectively counter the…

  6. Visual Inspection of Water Leakage from Ground Penetrating Radar Radargram

    Science.gov (United States)

    Halimshah, N. N.; Yusup, A.; Mat Amin, Z.; Ghazalli, M. D.

    2015-10-01

    Water loss in town and suburban is currently a significant issue which reflect the performance of water supply management in Malaysia. Consequently, water supply distribution system has to be maintained in order to prevent shortage of water supply in an area. Various techniques for detecting a mains water leaks are available but mostly are time-consuming, disruptive and expensive. In this paper, the potential of Ground Penetrating Radar (GPR) as a non-destructive method to correctly and efficiently detect mains water leaks has been examined. Several experiments were designed and conducted to prove that GPR can be used as tool for water leakage detection. These include instrument validation test and soil compaction test to clarify the maximum dry density (MDD) of soil and simulation studies on water leakage at a test bed consisting of PVC pipe burying in sand to a depth of 40 cm. Data from GPR detection are processed using the Reflex 2D software. Identification of water leakage was visually inspected from the anomalies in the radargram based on GPR reflection coefficients. The results have ascertained the capability and effectiveness of the GPR in detecting water leakage which could help avoiding difficulties with other leak detection methods.

  7. Effect of Surface Treatments on Leakage of Zirconium Oxide Ceramics

    Directory of Open Access Journals (Sweden)

    Göknil Alkan Demetoğlu

    2016-08-01

    Full Text Available Objective: The aim of this pilot study was to compare the effects of pretreatments on leakage of zirconia ceramics. Materials and Methods: The speciments divided into 6 groups that were subsequently treated as follows: group 1, no treatment (control; group 2, the ceramic surfaces were airborne-particle abraded with 110 μm aluminum-oxide (Al2O3 particles; group 3, after abrasion of the surfaces with 110 μm Al2O3 particles, silica coating using 30 μm (Al2O3 particles modified by silica (rocatec system and application of the silane coupling agent (espe-sil; group 4, ceramic surfaces irritated with neodymium-doped yttrium aluminium garnet (Nd:YAG laser [fidelis plus 3 foton (Ljubljana, Slovenia] at 20 hz, 100 mj, 2 w, 100 μs; group 5, ceramic surfaces irritated with Nd:YAG laser at fidelis plus 3 fotona (Ljubljana, Slovenia at 20 hz, 100 mj, 2 w, 100 μs; group 6; application of a zirconia primer (z-prime plus bisco, IL, USA agent. And all ceramics tested for leakage. Results: For marginal leakage, score 0 was found in all groups. Conclusion: No significant differences were found in marginal leakage under all conditions.

  8. Anastomotic leakage after anterior resection for rectal cancer: risk factors

    DEFF Research Database (Denmark)

    Bertelsen, C A; Andreasen, A H; Jørgensen, Torben;

    2010-01-01

    OBJECTIVE: The study aimed to identify risk factors for clinical anastomotic leakage (AL) after anterior resection for rectal cancer in a consecutive national cohort. METHOD: All patients with an initial first diagnosis of colorectal adenocarcinoma were prospectively registered in a national...

  9. The effect of macromolecular crowding on the structure of the protein complex superoxide dismutase

    Science.gov (United States)

    Rajapaksha Mudalige, Ajith Rathnaweera

    Biological environments contain between 7 - 40% macromolecules by volume. This reduces the available volume for macromolecules and elevates the osmotic pressure relative to pure water. Consequently, biological macromolecules in their native environments tend to adopt more compact and dehydrated conformations than those in vitro. This effect is referred to as macromolecular crowding and constitutes an important physical difference between native biological environments and the simple solutions in which biomolecules are usually studied. We used small angle scattering (SAS) to measure the effects of macromolecular crowding on the size of a protein complex, superoxide dismutase (SOD). Crowding was induced using 400 MW polyethylene glycol (PEG), triethylene glycol (TEG), methyl-alpha-glucoside (alpha-MG) and trimethylamine N-oxide (TMAO). Parallel small angle neutron scattering (SANS) and small angle X-ray scattering (SAXS) allowed us to unambiguously attribute apparent changes in radius of gyration to changes in the structure of SOD. For a 40% PEG solution, we find that the volume of SOD was reduced by 9%. SAS coupled with osmotic pressure measurements allowed us to estimate a compressibility modulus for SOD. We believe this to be the first time the osmotic compressibility of a protein complex was measured. Molecular Dynamics (MD) simulations are widely used to obtain insights on biomolecular processes. However, it is not clear whether MD is capable of predicting subtle effects of macromolecular crowding. We used our experimentally observed compressibility of SOD to evaluate the ability of MD to predict macromolecular crowding. Effects of macromolecular crowding due to PEG on SOD were modeled using an all atom MD simulation with the CHARMM forcefield and the crystallographically resolved structures of SOD and PEG. Two parallel MD simulations were performed for SOD in water and SOD in 40% PEG for over 150~ns. Over the period of the simulation the SOD structure in 40

  10. Biliary leakage after urgent cholecystectomy: Optimizationof endoscopic treatment

    Institute of Scientific and Technical Information of China (English)

    2015-01-01

    AIM To investigate the results of endoscopic treatmentof postoperative biliary leakage occurring after urgentcholecystectomy with a long-term follow-up.METHODS: This is an observational database studyconducted in a tertiary care center. All consecutivepatientswho underwent endoscopic retrograde cholangiography(ERC) for presumed postoperative biliaryleakage after urgent cholecystectomy in the periodbetween April 2008 and April 2013 were consideredfor this study. Patients with bile duct transection andbiliary strictures were excluded. Biliary leakage wassuspected in the case of bile appearance from eitherpercutaneous drainage of abdominal collection orabdominal drain placed at the time of cholecystectomy.Procedural and main clinical characteristics of allconsecutive patients with postoperative biliary leakageafter urgent cholecystectomy, such as indication forcholecystectomy, etiology and type of leakage, ERCfindings and post-ERC complications, were collectedfrom our electronic database. All patients in whomthe leakage was successfully treated endoscopicallywere followed-up after they were discharged from thehospital and the main clinical characteristics, laboratorydata and common bile duct diameter were electronicallyrecorded.RESULTS: During a five-year period, biliary leakagewas recognized in 2.2% of patients who underwenturgent cholecystectomy. The median time fromcholecystectomy to ERC was 6 d (interquartile range,4-11 d). Endoscopic interventions to manage biliaryleakage included biliary stent insertion with or withoutbiliary sphincterotomy. In 23 (77%) patients after firstendoscopic treatment bile flow through existing surgicaldrain ceased within 11 d following biliary therapeuticendoscopy (median, 4 d; interquartile range, 2-8 d).In those patients repeat ERC was not performed and the biliary stent was removed on gastroscopy. In seven(23%) patients repeat ERC was done within one tofourth week after their first ERC, depending on theextent

  11. The Study of the Recognizability of Electromagnetic Leakage Information Arising from Computer

    Institute of Scientific and Technical Information of China (English)

    ZHANG Hong-xin; LU Ying-hua; QIU Yu-chun; CHEN Da-qing

    2004-01-01

    The electromagnetic radiation will result in information leakage when computers work. This paper presents the recognition technology of information leakage caused by video signal electromagnetic radiation. To get the intact and useful information of video signals conveniengtly, the pattern recognition method based on artificial neural networks is proposed. In the last part, the primary word image recovered from the electromagnetic leakage is recognized and reconstructed and the recognizability of the information leakage from computers is discussed.

  12. Localization of protein aggregation in Escherichia coli is governed by diffusion and nucleoid macromolecular crowding effect.

    Science.gov (United States)

    Coquel, Anne-Sophie; Jacob, Jean-Pascal; Primet, Mael; Demarez, Alice; Dimiccoli, Mariella; Julou, Thomas; Moisan, Lionel; Lindner, Ariel B; Berry, Hugues

    2013-04-01

    Aggregates of misfolded proteins are a hallmark of many age-related diseases. Recently, they have been linked to aging of Escherichia coli (E. coli) where protein aggregates accumulate at the old pole region of the aging bacterium. Because of the potential of E. coli as a model organism, elucidating aging and protein aggregation in this bacterium may pave the way to significant advances in our global understanding of aging. A first obstacle along this path is to decipher the mechanisms by which protein aggregates are targeted to specific intercellular locations. Here, using an integrated approach based on individual-based modeling, time-lapse fluorescence microscopy and automated image analysis, we show that the movement of aging-related protein aggregates in E. coli is purely diffusive (Brownian). Using single-particle tracking of protein aggregates in live E. coli cells, we estimated the average size and diffusion constant of the aggregates. Our results provide evidence that the aggregates passively diffuse within the cell, with diffusion constants that depend on their size in agreement with the Stokes-Einstein law. However, the aggregate displacements along the cell long axis are confined to a region that roughly corresponds to the nucleoid-free space in the cell pole, thus confirming the importance of increased macromolecular crowding in the nucleoids. We thus used 3D individual-based modeling to show that these three ingredients (diffusion, aggregation and diffusion hindrance in the nucleoids) are sufficient and necessary to reproduce the available experimental data on aggregate localization in the cells. Taken together, our results strongly support the hypothesis that the localization of aging-related protein aggregates in the poles of E. coli results from the coupling of passive diffusion-aggregation with spatially non-homogeneous macromolecular crowding. They further support the importance of "soft" intracellular structuring (based on macromolecular

  13. D3, the new diffractometer for the macromolecular crystallography beamlines of the Swiss Light Source

    Energy Technology Data Exchange (ETDEWEB)

    Fuchs, Martin R., E-mail: mfuchs@bnl.gov [Paul Scherrer Institute, 5232 Villigen PSI (Switzerland); Brookhaven National Laboratory, Mail Stop 745, Upton, NY 11973 (United States); Pradervand, Claude; Thominet, Vincent; Schneider, Roman; Panepucci, Ezequiel; Grunder, Marcel; Gabadinho, Jose; Dworkowski, Florian S. N.; Tomizaki, Takashi; Schneider, Jörg; Mayer, Aline; Curtin, Adrian; Olieric, Vincent; Frommherz, Uli; Kotrle, Goran; Welte, Jörg; Wang, Xinyu; Maag, Stephan [Paul Scherrer Institute, 5232 Villigen PSI (Switzerland); Schulze-Briese, Clemens [DECTRIS Ltd, Neuenhoferstrasse 107, 5400 Baden (Switzerland); Wang, Meitian [Paul Scherrer Institute, 5232 Villigen PSI (Switzerland)

    2014-02-04

    A new diffractometer for microcrystallography has been developed for the three macromolecular crystallography beamlines of the Swiss Light Source. A new diffractometer for microcrystallography has been developed for the three macromolecular crystallography beamlines of the Swiss Light Source. Building upon and critically extending previous developments realised for the high-resolution endstations of the two undulator beamlines X06SA and X10SA, as well as the super-bend dipole beamline X06DA, the new diffractometer was designed to the following core design goals. (i) Redesign of the goniometer to a sub-micrometer peak-to-peak cylinder of confusion for the horizontal single axis. Crystal sizes down to at least 5 µm and advanced sample-rastering and scanning modes are supported. In addition, it can accommodate the new multi-axis goniometer PRIGo (Parallel Robotics Inspired Goniometer). (ii) A rapid-change beam-shaping element system with aperture sizes down to a minimum of 10 µm for microcrystallography measurements. (iii) Integration of the on-axis microspectrophotometer MS3 for microscopic sample imaging with 1 µm image resolution. Its multi-mode optical spectroscopy module is always online and supports in situ UV/Vis absorption, fluorescence and Raman spectroscopy. (iv) High stability of the sample environment by a mineral cast support construction and by close containment of the cryo-stream. Further features are the support for in situ crystallization plate screening and a minimal achievable detector distance of 120 mm for the Pilatus 6M, 2M and the macromolecular crystallography group’s planned future area detector Eiger 16M.

  14. Localization of protein aggregation in Escherichia coli is governed by diffusion and nucleoid macromolecular crowding effect.

    Directory of Open Access Journals (Sweden)

    Anne-Sophie Coquel

    2013-04-01

    Full Text Available Aggregates of misfolded proteins are a hallmark of many age-related diseases. Recently, they have been linked to aging of Escherichia coli (E. coli where protein aggregates accumulate at the old pole region of the aging bacterium. Because of the potential of E. coli as a model organism, elucidating aging and protein aggregation in this bacterium may pave the way to significant advances in our global understanding of aging. A first obstacle along this path is to decipher the mechanisms by which protein aggregates are targeted to specific intercellular locations. Here, using an integrated approach based on individual-based modeling, time-lapse fluorescence microscopy and automated image analysis, we show that the movement of aging-related protein aggregates in E. coli is purely diffusive (Brownian. Using single-particle tracking of protein aggregates in live E. coli cells, we estimated the average size and diffusion constant of the aggregates. Our results provide evidence that the aggregates passively diffuse within the cell, with diffusion constants that depend on their size in agreement with the Stokes-Einstein law. However, the aggregate displacements along the cell long axis are confined to a region that roughly corresponds to the nucleoid-free space in the cell pole, thus confirming the importance of increased macromolecular crowding in the nucleoids. We thus used 3D individual-based modeling to show that these three ingredients (diffusion, aggregation and diffusion hindrance in the nucleoids are sufficient and necessary to reproduce the available experimental data on aggregate localization in the cells. Taken together, our results strongly support the hypothesis that the localization of aging-related protein aggregates in the poles of E. coli results from the coupling of passive diffusion-aggregation with spatially non-homogeneous macromolecular crowding. They further support the importance of "soft" intracellular structuring (based on

  15. Optimized beamline design for macromolecular crystallography at the Cornell High Energy Synchrotron Source (CHESS) (abstract)

    Science.gov (United States)

    Schildkamp, Wilfried; Bilderback, Donald; Moffat, Keith

    1989-07-01

    The A1 station on the CHESS wiggler beamline has been the workhorse for most macromolecular crystallographic experiments. This station is equipped with a fixed energy focusing germanium (111) monochromator and a focusing total reflection mirror. Our macromolecular crystallographers made full use of the high flux of more than 1012 photons/s/mm2 and the stable beam conditions, both in position and energy resolution. As a result, the A1 station was heavily oversubscribed. CHESS is presently expanding its capabilities and a new diffraction station for macromolecular crystallography is under construction. This beamline will be powered by a 24-pole hybrid permanent magnet wiggler with a critical energy of 25 keV. A focusing monochromator, which handles a specific heat load of 10 W/mm2, will have a range of tunability which covers all relevant absorption edges from 7 to 15 keV using a Ge(111) crystal. The energy resolution and the focusing properties remain constant within a factor of 2 over the entire tunability range. We expect a brilliance of about 1013 photons/s/mm2/mrad2/0.1% bandpass. The diffraction station will be equipped with an oscillation camera which can be used with x-ray film of 5×5 or 8×10 in. size or alternatively with Kodak storage phosphors. A wide variety of clamp-on accessories, like crystal coolers, fast shutters, helium pathways, polarimeter, etc. are available. The station will contain a beampipe system, which can also be used for small angle scattering experiments with sample-to-detector distances of up to 3000 mm. The entire diffraction station, its control area, a biological preparation area, and a darkroom are to be embedded in a biological safety containment of the level BL3. This will allow diffraction studies of virulent strains of viruses and other biohazards, which could not previously be studied at synchrotron radiation sources before without causing major disruption to the normal laboratory procedure.

  16. Enhanced delivery of the RAPTA-C macromolecular chemotherapeutic by conjugation to degradable polymeric micelles.

    Science.gov (United States)

    Blunden, Bianca M; Lu, Hongxu; Stenzel, Martina H

    2013-12-09

    Macromolecular ruthenium complexes are a promising avenue to better and more selective chemotherapeutics. We have previously shown that RAPTA-C [RuCl2(p-cymene)(PTA)], with the water-soluble 1,3,5-phosphaadamantane (PTA) ligand, could be attached to a polymer moiety via nucleophilic substitution of an available iodide with an amide in the PTA ligand. To increase the cell uptake of this macromolecule, we designed an amphiphilic block copolymer capable of self-assembling into polymeric micelles. The block copolymer was prepared by ring-opening polymerization of d,l-lactide (3,6-dimethyl-1,4-dioxane-2,5-dione) using a RAFT agent with an additional hydroxyl functionality, followed by the RAFT copolymerization of 2-hydroxyethyl acrylate (HEA) and 2-chloroethyl methacrylate (CEMA). The Finkelstein reaction and reaction with PTA led to polymers that can readily react with the dimer of RuCl2(p-cymene) to create a macromolecular RAPTA-C drug. RAPTA-C conjugation, micellization, and subsequent cytotoxicity and cell uptake of these polymeric moieties was tested on ovarian cancer A2780, A2780cis, and Ovcar-3 cell lines. Confocal microscopy images confirmed cell uptake of the micelles into the lysosome of the cells, indicative of an endocytic pathway. On average, a 10-fold increase in toxicity was found for the macromolecular drugs when compared to the RAPTA-C molecule. Furthermore, the cell uptake of ruthenium was analyzed and a significant increase was found for the micelles compared to RAPTA-C. Notably, micelles prepared from the polymer containing fewer HEA units had the highest cytotoxicity, the best cell uptake of ruthenium and were highly effective in suppressing the colony-forming ability of cells.

  17. A Web Resource for Standardized Benchmark Datasets, Metrics, and Rosetta Protocols for Macromolecular Modeling and Design.

    Directory of Open Access Journals (Sweden)

    Shane Ó Conchúir

    Full Text Available The development and validation of computational macromolecular modeling and design methods depend on suitable benchmark datasets and informative metrics for comparing protocols. In addition, if a method is intended to be adopted broadly in diverse biological applications, there needs to be information on appropriate parameters for each protocol, as well as metrics describing the expected accuracy compared to experimental data. In certain disciplines, there exist established benchmarks and public resources where experts in a particular methodology are encouraged to supply their most efficient implementation of each particular benchmark. We aim to provide such a resource for protocols in macromolecular modeling and design. We present a freely accessible web resource (https://kortemmelab.ucsf.edu/benchmarks to guide the development of protocols for protein modeling and design. The site provides benchmark datasets and metrics to compare the performance of a variety of modeling protocols using different computational sampling methods and energy functions, providing a "best practice" set of parameters for each method. Each benchmark has an associated downloadable benchmark capture archive containing the input files, analysis scripts, and tutorials for running the benchmark. The captures may be run with any suitable modeling method; we supply command lines for running the benchmarks using the Rosetta software suite. We have compiled initial benchmarks for the resource spanning three key areas: prediction of energetic effects of mutations, protein design, and protein structure prediction, each with associated state-of-the-art modeling protocols. With the help of the wider macromolecular modeling community, we hope to expand the variety of benchmarks included on the website and continue to evaluate new iterations of current methods as they become available.

  18. A Web Resource for Standardized Benchmark Datasets, Metrics, and Rosetta Protocols for Macromolecular Modeling and Design.

    Science.gov (United States)

    Ó Conchúir, Shane; Barlow, Kyle A; Pache, Roland A; Ollikainen, Noah; Kundert, Kale; O'Meara, Matthew J; Smith, Colin A; Kortemme, Tanja

    2015-01-01

    The development and validation of computational macromolecular modeling and design methods depend on suitable benchmark datasets and informative metrics for comparing protocols. In addition, if a method is intended to be adopted broadly in diverse biological applications, there needs to be information on appropriate parameters for each protocol, as well as metrics describing the expected accuracy compared to experimental data. In certain disciplines, there exist established benchmarks and public resources where experts in a particular methodology are encouraged to supply their most efficient implementation of each particular benchmark. We aim to provide such a resource for protocols in macromolecular modeling and design. We present a freely accessible web resource (https://kortemmelab.ucsf.edu/benchmarks) to guide the development of protocols for protein modeling and design. The site provides benchmark datasets and metrics to compare the performance of a variety of modeling protocols using different computational sampling methods and energy functions, providing a "best practice" set of parameters for each method. Each benchmark has an associated downloadable benchmark capture archive containing the input files, analysis scripts, and tutorials for running the benchmark. The captures may be run with any suitable modeling method; we supply command lines for running the benchmarks using the Rosetta software suite. We have compiled initial benchmarks for the resource spanning three key areas: prediction of energetic effects of mutations, protein design, and protein structure prediction, each with associated state-of-the-art modeling protocols. With the help of the wider macromolecular modeling community, we hope to expand the variety of benchmarks included on the website and continue to evaluate new iterations of current methods as they become available.

  19. Injection Technique and Pen Needle Design Affect Leakage From Skin After Subcutaneous Injections

    DEFF Research Database (Denmark)

    Præstmark, Kezia Ann; Stallknecht, Bente; Jensen, Morten Lind;

    2016-01-01

    BACKGROUND: After a subcutaneous injection fluid might leak out of the skin, commonly referred to as leakage or backflow. The objective was to examine the influence of needle design and injection technique on leakage after injections in the subcutaneous tissue of humans and pigs. METHOD: Leakage...

  20. A conceptual framework and its application for addressing leakage: the case of avoided deforestation

    Energy Technology Data Exchange (ETDEWEB)

    Aukland, L.; Costa, P.M. [EcoSecurities Ltd., Oxford (United Kingdom); Brown, S. [Winrock International, Arlington, VA (United States)

    2003-06-01

    One of the most challenging technical issues associated with project-based mechanisms is that of leakage. A conceptual framework is proposed for the identification and analysis of leakage potentially generated by a project. The categorization of leakage based on the actors responsible for their manifestation is proposed, which divides sources of leakage into primary and secondary types. It is the actors or agents responsible for the baseline activities that cause primary leakage. Secondary leakage occurs when the project's outputs create incentives for third parties to increase emissions elsewhere. This distinction, based on the source of leakage, provides a basis for the analysis outlined in the paper. The extent and type of leakage will vary depending on the project typology and design. Using a decision tree approach, the process of identifying potential sources of leakage is demonstrated for the case study of avoided deforestation projects. If the main elements determining a baseline are properly identified and understood, in particular the 'baseline agents', a combination of the decision tree approach and apportioning responsibility, can assist in the quantification and monitoring of primary leakage. An analysis at the project design stage can also assist in minimizing the risk of future leakage. Econometric methods may prove more useful in analysing secondary leakage. (author)

  1. A conceptual framework and its application for addressing leakage. The case of avoided deforestation

    Energy Technology Data Exchange (ETDEWEB)

    Aukland, Louise; Costa, Pedro Moura [EcoSecurities Ltd., 45 Raleigh Park Road, Oxford OX2 9AZ (United Kingdom); Brown, Sandra [Winrock International, 1621 N Kent St., Suite 1200, Arlington, VA 22209 (United States)

    2003-06-01

    One of the most challenging technical issues associated with project-based mechanisms is that of leakage. A conceptual framework is proposed for the identification and analysis of leakage potentially generated by a project. The categorization of leakage based on the actors responsible for their manifestation is proposed, which divides sources of leakage into primary and secondary types. It is the actors or agents responsible for the baseline activities that cause primary leakage. Secondary leakage occurs when the project's outputs create incentives for third parties to increase emissions elsewhere. This distinction, based on the source of leakage, provides a basis for the analysis outlined in the paper. The extent and type of leakage will vary depending on the project typology and design. Using a decision tree approach, the process of identifying potential sources of leakage is demonstrated for the case study of avoided deforestation projects. If the main elements determining a baseline are properly identified and understood, in particular the 'baseline agents', a combination of the decision tree approach and apportioning responsibility, can assist in the quantification and monitoring of primary leakage. An analysis at the project design stage can also assist in minimizing the risk of future leakage. Econometric methods may prove more useful in analyzing secondary leakage.

  2. A vibrating membrane bioreactor (VMBR): Macromolecular transmission-influence of extracellular polymeric substances

    DEFF Research Database (Denmark)

    Beier, Søren; Jonsson, Gunnar Eigil

    2009-01-01

    The vibrating membrane bioreactor (VMBR) system facilitates the possibility of conducting a separation of macromolecules (BSA) from larger biological components (yeast cells) with a relatively high and stable macromolecular transmission at sub-critical flux. This is not possible to achieve...... for a static non-vibrating membrane module. A BSA transmission of 74% has been measured in the separation of 4g/L BSA from 8 g/L dry weight yeast cells in suspension at sub-critical flux (20L/(m(2) h)). However, this transmission is lower than the 85% BSA transmission measured for at pure 4g/L BSA solution...

  3. Simulation of macromolecular liquids with the adaptive resolution molecular dynamics technique

    Science.gov (United States)

    Peters, J. H.; Klein, R.; Delle Site, L.

    2016-08-01

    We extend the application of the adaptive resolution technique (AdResS) to liquid systems composed of alkane chains of different lengths. The aim of the study is to develop and test the modifications of AdResS required in order to handle the change of representation of large molecules. The robustness of the approach is shown by calculating several relevant structural properties and comparing them with the results of full atomistic simulations. The extended scheme represents a robust prototype for the simulation of macromolecular systems of interest in several fields, from material science to biophysics.

  4. The "macromolecular tourist": universal temperature dependence of thermal diffusion in aqueous colloidal suspensions.

    Science.gov (United States)

    Iacopini, S; Rusconi, R; Piazza, R

    2006-01-01

    By performing measurements on a large class of macromolecular and colloidal systems, we show that thermophoresis (particle drift induced by thermal gradients) in aqueous solvents displays a distinctive universal dependence on temperature. For systems of particles interacting via temperature-independent forces, this behavior is strictly related to the solvent thermal expansivity, while an additional, T-independent term is needed to account for the behavior of "thermophilic" (migrating to the warmth) particles. The former relation between thermophoresis and thermal expansion may be exploited to envisage other fruitful studies of colloidal diffusion in inhomogeneous fluids.

  5. INFLUENCE OF THE SOLVENT SWELLING ON MACROMOLECULAR CHOLESTERIC LIQUID CRYSTALLINE STRUCTURE

    Institute of Scientific and Technical Information of China (English)

    Jia Zeng; Yong Huang

    1999-01-01

    Ethyl-cyanoethyl cellulose [(E-CE)C]/cross-linked polyacrylic acid [PAA] molecular composites with cholesteric order were prepared. It was found that the macromolecular cholesteric structure was changed with the swelling of PAA in the composites. The selective reflection of the cholesteric phase shifted to the longer wavelength and the X-ray diffraction angle shifted to the high angle direction during swelling, which suggested that the cholesteric pitch and the number of the layers of ordered (E-CE)C chains in the cholesteric phase were increased.

  6. Chirality as a physical aspect of structure formation in biological macromolecular systems

    Science.gov (United States)

    Malyshko, E. V.; Tverdislov, V. A.

    2016-08-01

    A novel regularity of hierarchical structures is found in the formation of chiral biological macromolecular systems. The formation of structures with alternating chirality (helical structures) serves as an instrument of stratification. The ability of a carbon atom to form chiral compounds is an important factor that determined the carbon basis of living systems on the Earth as well as their development through a series of chiral bifurcations. In the course of biological evolution, the helical structures became basic elements of the molecular machines in the cell. The discreteness of structural levels allowed the mechanical degrees of freedom formation in the molecular machines in the cell.

  7. The Impact of Statistical Leakage Models on Design Yield Estimation

    Directory of Open Access Journals (Sweden)

    Rouwaida Kanj

    2011-01-01

    Full Text Available Device mismatch and process variation models play a key role in determining the functionality and yield of sub-100 nm design. Average characteristics are often of interest, such as the average leakage current or the average read delay. However, detecting rare functional fails is critical for memory design and designers often seek techniques that enable accurately modeling such events. Extremely leaky devices can inflict functionality fails. The plurality of leaky devices on a bitline increase the dimensionality of the yield estimation problem. Simplified models are possible by adopting approximations to the underlying sum of lognormals. The implications of such approximations on tail probabilities may in turn bias the yield estimate. We review different closed form approximations and compare against the CDF matching method, which is shown to be most effective method for accurate statistical leakage modeling.

  8. Distributed public key schemes secure against continual leakage

    DEFF Research Database (Denmark)

    Akavia, Adi; Goldwasser, Shafi; Hazay, Carmit

    2012-01-01

    -secure against continual memory leakage. Our DPKE scheme also implies a secure storage system on leaky devices, where a value s can be secretely stored on devices that continually leak information about their internal state to an external attacker. The devices go through a periodic refresh protocol......In this work we study distributed public key schemes secure against continual memory leakage. The secret key will be shared among two computing devices communicating over a public channel, and the decryption operation will be computed by a simple 2-party protocol between the devices. Similarly...... the value of the respective function on the internal state of the respective device (namely, on its secret share, internal randomness, and results of intermediate computations). We present distributed public key encryption (DPKE) and distributed identity based encryption (DIBE) schemes that are secure...

  9. Signature Schemes Secure against Hard-to-Invert Leakage

    DEFF Research Database (Denmark)

    Faust, Sebastian; Hazay, Carmit; Nielsen, Jesper Buus

    2012-01-01

    In the auxiliary input model an adversary is allowed to see a computationally hard-to-invert function of the secret key. The auxiliary input model weakens the bounded leakage assumption commonly made in leakage resilient cryptography as the hard-to-invert function may information-theoretically...... reveal the entire secret key. In this work, we propose the first constructions of digital signature schemes that are secure in the auxiliary input model. Our main contribution is a digital signature scheme that is secure against chosen message attacks when given an exponentially hard-to-invert function...... of the secret key. As a second contribution, we construct a signature scheme that achieves security for random messages assuming that the adversary is given a polynomial-time hard to invert function. Here, polynomial-hardness is required even when given the entire public-key – so called weak auxiliary input...

  10. A software sampling frequency adaptive algorithm for reducing spectral leakage

    Institute of Scientific and Technical Information of China (English)

    PAN Li-dong; WANG Fei

    2006-01-01

    Spectral leakage caused by synchronous error in a nonsynchronous sampling system is an important cause that reduces the accuracy of spectral analysis and harmonic measurement.This paper presents a software sampling frequency adaptive algorithm that can obtain the actual signal frequency more accurately,and then adjusts sampling interval base on the frequency calculated by software algorithm and modifies sampling frequency adaptively.It can reduce synchronous error and impact of spectral leakage;thereby improving the accuracy of spectral analysis and harmonic measurement for power system signal where frequency changes slowly.This algorithm has high precision just like the simulations show,and it can be a practical method in power system harmonic analysis since it can be implemented easily.

  11. An advanced leakage scheme for neutrino treatment in astrophysical simulations

    CERN Document Server

    Perego, Albino; Käppeli, Roger

    2015-01-01

    We present an Advanced Spectral Leakage (ASL) scheme to model neutrinos in the context of core-collapse supernovae and compact binary mergers. Based on previous gray leakage schemes, the ASL scheme computes the neutrino cooling rates by interpolating local production and diffusion rates (relevant in optically thin and thick regimes, respectively), separately for discretized values of the neutrino energy. Neutrino trapped components are also modeled, based on equilibrium and timescale arguments. The better accuracy achieved by the spectral treatment allows a more reliable computation of neutrino heating rates in optically thin conditions. The scheme has been calibrated and tested against Boltzmann transport in the context of Newtonian spherically symmetric models of core-collapse supernovae. ASL shows a very good qualitative and a partial quantitative agreement, for key quantities from collapse to a few hundreds of milliseconds after core bounce. We have proved the adaptability and flexibility of our ASL schem...

  12. Detection and quantification of methane leakage from landfills

    Energy Technology Data Exchange (ETDEWEB)

    Ljungberg, Sven-Aake; Maartensson, Stig-Goeran (Univ. of Gaevle, Gaevle (Sweden)); Meijer, Jan-Erik; Rosqvist, Haakan (NSR AB, Helsingborg (Sweden))

    2009-03-15

    The purpose of this project was to detect gas leakage and to measure and quantify methane emission from landfills using modern remote sensing techniques. In this project, a handheld laser instrument and an IR camera were used. The overall objective was to develop cost-effective methods for detecting and quantifying methane emissions from landfills. There are many methods available for measuring the methane concentration in air, both from close-up and from long distances. Combined with the use of a tracer gas, the methane emission from entire landfills can be measured relatively accurately. A number of methods are used to detect leakage from parts of landfill surfaces, but there are few methods for quantifying leakage from sub-zones. Field measurements with the laser instrument and the IR camera were carried out at seven Swedish landfills and two landfills in France. The investigated surfaces at the Swedish landfills were divided into different zones, such as top surface, slope, crest and toe of slope. The field measurements in France were taken over entire landfills. The methane emission varied between the different landfills in the project, and also between the different landfill zones. The results from repeated field measurements indicated that a landfill with a final cap and a successful gas recovery system produces barely measurable emissions. The weak points at a landfill are generally slopes, including crests and toes of slopes. Where the covering of the waste is inadequate, leakage often occurs at lift joints and in areas where waste protrudes through the cover. Other weak points are deficiencies in the gas recovery system. Leachate systems can lead landfill gas and thereby cause methane leakage. Along with wind velocity and variations in atmospheric pressure, moisture content in the ground is an important factor that affects methane emissions from landfill surfaces. Results from field measurements of the same feature/surface at different points in time and

  13. Evaluation of Leakage Current Measurement for Site Pollution Severity Assessment

    Directory of Open Access Journals (Sweden)

    Mohammad Ali Shercat MASOUM

    2007-01-01

    Full Text Available Flashover of insulators in transmission and distribution systems may cause costly outages for power companies and their customers. Industrial and/or coastal pollution of external insulation is a major cause for such events at the normal power frequency voltage of the systems. The power companies are now facing increasing competition resulting in pressure to lower the cost and to increase the system reliability. Different methods have been applied in the past to overcome or reduce the problems with flashover on insulators. Methods which should provide reliable data under real physical conditions. In this paper several measuring methods to evaluate the pollution levels on outdoor insulators are described. According to this comparison, Leakage Current Measurement ‘LCM’ method is a reliable method for measurement leakage current in outdoor insulators and surge arresters.

  14. Support calculations for management of PRISE leakage accidents

    Energy Technology Data Exchange (ETDEWEB)

    Matejovic, P.; Vranka, L. [Nuclear Power Plants Research Inst. Vuje, Trnava (Slovakia)

    1997-12-31

    Accidents involving primary-to-secondary leakage (PRISE) caused by rupture of one or a few tubes are well known design basis events in both, western and VVER NPPs. Operating experience and in-service inspections of VVER-440 units have demonstrated also the potential for large PRISE leaks in the case of the steam generator (SG) primary collector cover lift-up (Rovno NPP). Without performing any countermeasure for limitation of SG collector cover lift-up, a full opening results in PRISE leak with an equivalent diameter 107 mm. Although this accident was not considered in the original design, this event is usually analysed as DBA too. Different means are available for detection and mitigation of PRISE leakage in NPPs currently in operation (J.Bohunice V-1 and V-2) or under construction (Mochovce) in Slovakia. 8 refs.

  15. Impact of the Indonesian Throughflow on Agulhas leakage

    Directory of Open Access Journals (Sweden)

    D. Le Bars

    2013-09-01

    Full Text Available Using ocean models of different complexity we show that opening the Indonesian Passage between the Pacific and the Indian oceans increases the input of Indian Ocean water into the South Atlantic via the Agulhas leakage. In a strongly eddying global ocean model this response results from an increased Agulhas Current transport and a constant proportion of Agulhas retroflection south of Africa. The leakage increases through an increased frequency of ring shedding events. In an idealized two-layer and flat-bottom eddy resolving model, the proportion of the Agulhas Current transport that retroflects is (for a wide range of wind stress forcing not affected by an opening of the Indonesian Passage. Using a comparison with a linear model and previous work on the retroflection problem, the result is explained as a balance between two mechanisms: decrease retroflection due to large-scale momentum balance and increase due to local barotropic/baroclinic instabilities.

  16. Geochemical implications of brine leakage into freshwater aquifers.

    Science.gov (United States)

    Wunsch, Assaf; Navarre-Sitchler, Alexis K; McCray, John E

    2013-01-01

    CO(2) injection into deep saline formations as a way to mitigate climate change raises concerns that leakage of saline waters from the injection formations will impact water quality of overlying aquifers, especially underground sources of drinking water (USDWs). This paper aims to characterize the geochemical composition of deep brines, with a focus on constituents that pose a human health risk and are regulated by the U.S. Environmental Protection Agency (USEPA). A statistical analysis of the NATCARB brine database, combined with simple mixing model calculations, show total dissolved solids and concentrations of chloride, boron, arsenic, sulfate, nitrate, iron and manganese may exceed plant tolerance or regulatory levels. Twelve agricultural crops evaluated for decreased productivity in the event of brine leakage would experience some yield reduction due to increased TDS at brine-USDW ratios of United States are almost three times higher than public and domestic withdrawals.

  17. Overview of Quantum Error Prevention and Leakage Elimination

    CERN Document Server

    Byrd, M S; Lidar, D A; Byrd, Mark S.; Wu, Lian-Ao; Lidar, Daniel A.

    2004-01-01

    Quantum error prevention strategies will be required to produce a scalable quantum computing device and are of central importance in this regard. Progress in this area has been quite rapid in the past few years. In order to provide an overview of the achievements in this area, we discuss the three major classes of error prevention strategies, the abilities of these methods and the shortcomings. We then discuss the combinations of these strategies which have recently been proposed in the literature. Finally we present recent results in reducing errors on encoded subspaces using decoupling controls. We show how to generally remove mixing of an encoded subspace with external states (termed leakage errors) using decoupling controls. Such controls are known as ``leakage elimination operations'' or ``LEOs.''

  18. Bacterial coronal leakage after obturation with three root canal sealers.

    Science.gov (United States)

    Timpawat, S; Amornchat, C; Trisuwan, W R

    2001-01-01

    The purpose of this study was to compare the bacterial leakage of root canals obturated with three root canal sealers, using Endodontalis faecalis as a microbial tracer to determine the length of time for bacteria to penetrate through the obturated root canal to the root apex. Seventy-five, single-rooted teeth with straight root canals had the crown cut off at the cementoenamel junction. Root canals were instrumented by a step-back technique. The prepared teeth were randomly divided into 3 groups of 19 teeth each and another 2 groups as positive and negative controls (9 teeth each). The experimental groups were dependent on the sealer used: AH-Plus, Apexit, and Ketac-Endo. The root canals were obturated using a lateral condensation technique. After 24 h the teeth were attached to microcentrifuge tubes with 2 mm of the root apex submerged in Brain Heart Infusion broth in glass test tubes. The coronal portions of the root canal filling materials were placed in contact with E. faecalis. The teeth were observed for bacterial leakage daily for 30 and 60 days. With the chi2 test for comparing pairs of groups at the 0.05 level (p 0.06), but Apexit had significantly higher leakage (p 0.05), but Apexit leaked more than AH-Plus. The conclusion drawn from this experiment was that epoxy resin root canal sealer was found to be more adaptable to the root canal wall and filling material than a calcium hydroxide sealer when bacterial coronal leakage was studied.

  19. Giant mid-esophageal diverticulum. Conservative treatment of postoperative leakage.

    Science.gov (United States)

    Dallatomasina, S; Casaccia, M; Chessa, M; Serrano, J; Nardi, I; Troilo, B; Miggino, M; Valente, U

    2009-01-01

    Mid-esophageal diverticula are rare entities. Only symptomatic patients usually receive surgical treatment. Esophageal leakage is one of the most common complications after these procedures. Though in literature, operative management is the preferred treatment for esophageal fistula, conservative approach is described in case of small leaks. We report a case of an operated giant mid-esophageal diverticulum complicated with an esophageal fistula. The patient underwent a surgical treatment and recovered completely.

  20. Gas Turbine Tip Region Leakage Flow and Heat Transfer

    Science.gov (United States)

    2005-09-07

    overlapped with a color map of scalar SMOKE VISULIZATION magnitudes, which are divided by the cascade exit velocity, in Smoke visualization was carried out...34Rotor-Tip Leakage: Part I - Basic Methodology," pressure on the over-tip casing wall of an axial turbine ASME Journal of Engineering for Power, Vol. 104...blade was compared with results ofwerewrapedarond rofledribs Th tet badedifers Durham University and revealed excellent match, assuring thefrom the

  1. Exchange-Rate Unification with Black Market Leakages; Russia 1992

    OpenAIRE

    Goldberg, L. S.

    1993-01-01

    In 1992 Russia unified the multiple exchange rates that had applied to international transactions. This paper describes the multiple exchange rate system that existed in Russia prior to mid-1992 and undertakes a theoretical exploration of the effects of the exchange rate unification that took place in July 1992. The model developed here allows for leakages between official and black markets and permits flexibility of the exchange rates in both official and parallel currency markets. Within th...

  2. Oil Leakage from the Seal Ring of a Scroll Compressor

    Science.gov (United States)

    Kobayashi, Naoki; Fukui, Atsushi; Horiguchi, Hironori; Tsujimoto, Yoshinobu; Toyama, Toshiyuki

    In scroll compressors for air conditioners, there is a compressor with back-pressure chamber spaced by seal ring behind orbiting scroll. High pressure in the backpressure chamber presses the orbiting scroll to fixed scroll. In the case that lubrication oil and refrigerant gas with high pressure and temperature in the backpressure chamber leak to low pressure chamber through the seal ring, the efficiency of compressor decreases and the oil circulation rate can increase. In the present study the leakage characteristics of lubrication oil from the backpressure chamber to the low pressure chamber were investigated. In experiment, it was found that the oil leakage is larger for higher rotational speed of rotating disk, higher viscosity of oil and smaller pressure difference between the backpressure and low-pressure chambers. This could be explained by the calculation in which the seal ring was assumed to have a tilt angle. It was also found in the calculation that oil leakage is larger due to the thicker oil film between the seal ring and the rotating disk in the case of higher rotational speed of the disk, higher viscosity of oil and smaller pressure difference between the backpressure and low-pressure chambers.

  3. A Minimum Leakage Quasi-Static RAM Bitcell

    Directory of Open Access Journals (Sweden)

    Adam Teman

    2011-05-01

    Full Text Available As SRAMs continue to grow and comprise larger percentages of the area and power consumption in advanced systems, the need to minimize static currents becomes essential. This brief presents a novel 9T Quasi-Static RAM Bitcell that provides aggressive leakage reduction and high write margins. The quasi-static operation method of this cell, based on internal feedback and leakage ratios, minimizes static power while maintaining sufficient, albeit depleted, noise margins. This paper presents the concept of the novel cell, and discusses the stability of the cell under hold, read and write operations. The cell was implemented in a low-power 40 nm TSMC process, showing as much as a 12× reduction in leakage current at typical conditions, as compared to a standard 6T or 8T bitcell at the same supply voltage. The implemented cell showed full functionality under global and local process variations at nominal and low voltages, as low as 300 mV.

  4. Surface Leakage Mechanisms in III-V Infrared Barrier Detectors

    Science.gov (United States)

    Sidor, D. E.; Savich, G. R.; Wicks, G. W.

    2016-09-01

    Infrared detector epitaxial structures employing unipolar barriers exhibit greatly reduced dark currents compared to simple pn-based structures. When correctly positioned within the structure, unipolar barriers are highly effective at blocking bulk dark current mechanisms. Unipolar barriers are also effective at suppressing surface leakage current in infrared detector structures employing absorbing layers that possess the same conductivity type in their bulk and at their surface. When an absorbing layer possesses opposite conductivity types in its bulk and at its surface, unipolar barriers are not solutions to surface leakage. This work reviews empirically determined surface band alignments of III-V semiconductor compounds and modeled surface band alignments of both gallium-free and gallium-containing type-II strained layer superlattice material systems. Surface band alignments are used to predict surface conductivity types in several detector structures, and the relationship between surface and bulk conductivity types in the absorbing layers of these structures is used as the basis for explaining observed surface leakage characteristics.

  5. Subsurface Barrier Formation as a CO2 Leakage Mitigation Technology

    Science.gov (United States)

    Castaneda Herrera, C. A.; Stevens, G.; Haese, R. R.

    2015-12-01

    Long-term CO2 containment in a geological storage reservoir is a key criterion for successfully implementing carbon capture and storage (CCS), however, CO2 leakage through different pathways cannot be completely ruled out in some instances. In this study we investigate the conditions for reactive barrier formation as a technology to mitigate and remediate CO2 leakage. We propose to inject a liquid reagent consistent of an alkaline sodium-silicate solution on top of the storage caprock, which will lead to silica mineral precipitation when in contact with an acidic, CO2-enriched fluid. This reaction will create a barrier that seals the leakage by reducing the permeability. Preliminary modelling has shown that the density, viscosity and alkalinity of the reagent fluid are critical for a successful seal formation, whereas differences in formation water composition and in the rock mineral composition are less important. In order to study the reaction through experiments, different reagent solutions were prepared and characterised in terms of silica concentration, density, viscosity and buffer capacity. In a static, diffusion-controlled batch experiment we observed silica mineral precipitation in the outer layer of the piece of rock inhibiting further mixing of the two fluids and slowing down the initial reaction rate. Core-flood experiments will be carried out to simulate barrier formation under fluid flow conditions. Here, the sealing efficiency of the reaction will be continuously measured in terms of a change in permeability.

  6. Indoor-Outdoor Air Leakage of Apartments and Commercial Buildings

    Energy Technology Data Exchange (ETDEWEB)

    Price, P.N.; Shehabi, A.; Chan, R.W.; Gadgil, A.J.

    2006-06-01

    We compiled and analyzed available data concerning indoor-outdoor air leakage rates and building leakiness parameters for commercial buildings and apartments. We analyzed the data, and reviewed the related literature, to determine the current state of knowledge of the statistical distribution of air exchange rates and related parameters for California buildings, and to identify significant gaps in the current knowledge and data. Very few data were found from California buildings, so we compiled data from other states and some other countries. Even when data from other developed countries were included, data were sparse and few conclusive statements were possible. Little systematic variation in building leakage with construction type, building activity type, height, size, or location within the u.s. was observed. Commercial buildings and apartments seem to be about twice as leaky as single-family houses, per unit of building envelope area. Although further work collecting and analyzing leakage data might be useful, we suggest that a more important issue may be the transport of pollutants between units in apartments and mixed-use buildings, an under-studied phenomenon that may expose occupants to high levels of pollutants such as tobacco smoke or dry cleaning fumes.

  7. Air Leakage and Air Transfer Between Garage and Living Space

    Energy Technology Data Exchange (ETDEWEB)

    Rudd, Armin [Building Science Corporation, Westford, MA (United States)

    2014-09-01

    This research project focused on evaluation of air transfer between the garage and living space in a single-family detached home constructed by a production homebuilder in compliance with the 2009 International Residential Code and the 2009 International Energy Conservation Code. The project gathered important information about the performance of whole-building ventilation systems and garage ventilation systems as they relate to minimizing flow of contaminated air from garage to living space. A series of 25 multi-point fan pressurization tests and additional zone pressure diagnostic testing characterized the garage and house air leakage, the garage-to-house air leakage, and garage and house pressure relationships to each other and to outdoors using automated fan pressurization and pressure monitoring techniques. While the relative characteristics of this house may not represent the entire population of new construction configurations and air tightness levels (house and garage) throughout the country, the technical approach was conservative and should reasonably extend the usefulness of the results to a large spectrum of house configurations from this set of parametric tests in this one house. Based on the results of this testing, the two-step garage-to-house air leakage test protocol described above is recommended where whole-house exhaust ventilation is employed.

  8. Leakage Current Characteristics of Pre-flashover Along Ice-covered Insulator String%Leakage Current Characteristics of Pre-flashover Along Ice-covered Insulator String

    Institute of Scientific and Technical Information of China (English)

    LI Zhou; ZHANG Qiao-gen; LIU Feng-lian; JIA Hui-dong; XI Hai-bo

    2011-01-01

    Flashover of ice-covered in power grid. As leakage current suspension insulator string is one of the is one of the important characteristics to major problems for the transmission lines predict the flashover of suspension insulator string, measuring method and analysis of the leakage current are developed for ice-covered XWP2-160 porcelain suspension insulator string in this paper. The waveform of the leakage current is perfectly recorded from the occurrence of micro-discharge to flashover, in which the process can be divided into four periods according to the evolution of the leakage current. There are different rising rates of the leakage current and various phenomena of arc discharge in different periods with the increase of the applied voltage, and the distortion on the leakage current waveform is detected because of the effect of arc discharge. A characteristic current (Iw)and a critical current (IFT)of flashover, two important parameters of the leakage current before ice-covered insulator string flashover, are defined for analysis of the leakage current characteristics of pre-flashover along the polluted insulator string covered with ice. Statistical experimental results show that the average values of Iw and IFT are within the major distribution zones, and both currents can be used for predicting the icing flashover. The values of two important leakage currents are approximately constant at different contamination degrees, while the direct relationships between the critical currents and the contamination degrees are not found in this paper.

  9. Macromolecular liquids

    Energy Technology Data Exchange (ETDEWEB)

    Safinya, C.R.; Safran, S.A. (Exxon Research and Engineering Co., Annandale, NJ (US)); Pincus, P.A. (Univ. of California at Santa Barbara, Santa Barbara, CA (US))

    1990-01-01

    Liquids include a broad range of material systems which are of high scientific and technological interest. Generally speaking, these are partially ordered or disordered phases where the individual molecular species have organized themselves on length scales which are larger than simple fluids, typically between 10 Angstroms and several microns. The specific systems reported on in this book include membranes, microemulsions, micelles, liquid crystals, colloidal suspensions, and polymers. They have a major impact on a broad spectrum of technological industries such as displays, plastics, soap and detergents, chemicals and petroleum, and pharmaceuticals.

  10. A NEW UNSTEADY THREE DIMENSIONAL MODEL FOR MACROMOLECULAR TRANSPORT AND WATER FILTRATION ACROSS THE ARTERIAL WALL

    Institute of Scientific and Technical Information of China (English)

    黄浩; 温功碧

    2001-01-01

    A new unsteady three-dimensional convective-diffusive mathematical model for the transportation of macromolecules and water across the arterial wall was proposed . After the formation of leaky junctions due to the mitosis of endothelial cell of the arterial wall, the macromolecular transport happens surrounding the leaky cells. The arterial wall was divided into four layers: the endothelial layer, the subendothelial intima, the internal elastic lamina and the media for the convenience of research. The time-dependent concentration growth,the effect of the shape of endothelial cell and the effect of physiological parameters were analyzed. The analytical solution of velocity field and pressure field of water flow across the arterial wall were obtained; and concentration distribution of three macromolecules ; LDL,HRP and Albumin, were calculated with numerical simulation method. The new theory predicts, the maximum and distribution areas of time dependent concentration with round shape endothelial cell are both larger than that with ellipse-shape endothelial cell. The model also predicts the concentration growth is much alike that of a two-dimensional model and it shows that the concentration reaches its peak at the leaky junction where atherosclerotic formation frequently occurs and falls down rapidly in a limited area beginning from its earlier time growth to the state when macromolecular transfer approaches steadily. These predictions of the new model are in agreement with the experimental observation for the growth and concentration distribution of LDL and Albumin.

  11. X-ray Diffraction of Cotton Treated with Neutralized Vegetable Oil-based Macromolecular Crosslinkers

    Directory of Open Access Journals (Sweden)

    James W. Rawlins, Ph.D.

    2010-03-01

    Full Text Available Maleinized soybean oil (MSO has been investigated as a flexible, macromolecular crosslinker for cotton fabrics. The ability of MSO to penetrate crystalline cellulose and crosslink aligned cellulose chains upon cure has been in question. This study compares the penetration capability of MSO to dimethyloldihydroxyethyleneurea (DMDHEU, which is the commercial standard for durable press finishing and is an efficient cellulose crosslinker. X-ray diffraction was employed to characterize changes in the crystalline morphology upon heating un-mercerized cotton fabrics treated with aqueous DMDHEU and soybean oil derivatives. Displacement of characteristic interplanar spacings and the genesis/elimination of diffraction intensities from quintessential planes were evidence of structural modification. The penetration of ammonia neutralized MSO (acid value 230.00 mg KOH/g into the microstructure of cotton cellulose is similar to that of DMDHEU in terms of expanding the interplanar spacings of characteristic planes. Moreover, polymorphism of cotton and mercerized cotton occurred upon treatment with aqueous solutions of MSO. These findings suggest that macromolecular reagents can diffuse into cellulose fibrils if they are sufficiently hydrated or enshrouded by more favored penetrants.

  12. Influence of macromolecular architecture on necking in polymer extrusion film casting process

    Energy Technology Data Exchange (ETDEWEB)

    Pol, Harshawardhan; Banik, Sourya; Azad, Lal Busher; Doshi, Pankaj; Lele, Ashish [CSIR-National Chemical Laboratory, Pune, Maharashtra (India); Thete, Sumeet [Purdue University, West Lafayette, Indiana (United States)

    2015-05-22

    Extrusion film casting (EFC) is an important polymer processing technique that is used to produce several thousand tons of polymer films/coatings on an industrial scale. In this research, we are interested in understanding quantitatively how macromolecular chain architecture (for example long chain branching (LCB) or molecular weight distribution (MWD or PDI)) influences the necking and thickness distribution of extrusion cast films. We have used different polymer resins of linear and branched molecular architecture to produce extrusion cast films under controlled experimental conditions. The necking profiles of the films were imaged and the velocity profiles during EFC were monitored using particle tracking velocimetry (PTV) technique. Additionally, the temperature profiles were captured using an IR thermography and thickness profiles were calculated. The experimental results are compared with predictions of one-dimensional flow model of Silagy et al{sup 1} wherein the polymer resin rheology is modeled using molecular constitutive equations such as the Rolie-Poly (RP) and extended Pom Pom (XPP). We demonstrate that the 1-D flow model containing the molecular constitutive equations provides new insights into the role of macromolecular chain architecture on film necking.{sup 1}D. Silagy, Y. Demay, and J-F. Agassant, Polym. Eng. Sci., 36, 2614 (1996)

  13. A brief history of macromolecular crystallography, illustrated by a family tree and its Nobel fruits.

    Science.gov (United States)

    Jaskolski, Mariusz; Dauter, Zbigniew; Wlodawer, Alexander

    2014-09-01

    As a contribution to the celebration of the year 2014, declared by the United Nations to be 'The International Year of Crystallography', the FEBS Journal is dedicating this issue to papers showcasing the intimate union between macromolecular crystallography and structural biology, both in historical perspective and in current research. Instead of a formal editorial piece, by way of introduction, this review discusses the most important, often iconic, achievements of crystallographers that led to major advances in our understanding of the structure and function of biological macromolecules. We identified at least 42 scientists who received Nobel Prizes in Physics, Chemistry or Medicine for their contributions that included the use of X-rays or neutrons and crystallography, including 24 who made seminal discoveries in macromolecular sciences. Our spotlight is mostly, but not only, on the recipients of this most prestigious scientific honor, presented in approximately chronological order. As a summary of the review, we attempt to construct a genealogy tree of the principal lineages of protein crystallography, leading from the founding members to the present generation.

  14. MxCuBE: a synchrotron beamline control environment customized for macromolecular crystallography experiments.

    Science.gov (United States)

    Gabadinho, José; Beteva, Antonia; Guijarro, Matias; Rey-Bakaikoa, Vicente; Spruce, Darren; Bowler, Matthew W; Brockhauser, Sandor; Flot, David; Gordon, Elspeth J; Hall, David R; Lavault, Bernard; McCarthy, Andrew A; McCarthy, Joanne; Mitchell, Edward; Monaco, Stéphanie; Mueller-Dieckmann, Christoph; Nurizzo, Didier; Ravelli, Raimond B G; Thibault, Xavier; Walsh, Martin A; Leonard, Gordon A; McSweeney, Sean M

    2010-09-01

    The design and features of a beamline control software system for macromolecular crystallography (MX) experiments developed at the European Synchrotron Radiation Facility (ESRF) are described. This system, MxCuBE, allows users to easily and simply interact with beamline hardware components and provides automated routines for common tasks in the operation of a synchrotron beamline dedicated to experiments in MX. Additional functionality is provided through intuitive interfaces that enable the assessment of the diffraction characteristics of samples, experiment planning, automatic data collection and the on-line collection and analysis of X-ray emission spectra. The software can be run in a tandem client-server mode that allows for remote control and relevant experimental parameters and results are automatically logged in a relational database, ISPyB. MxCuBE is modular, flexible and extensible and is currently deployed on eight macromolecular crystallography beamlines at the ESRF. Additionally, the software is installed at MAX-lab beamline I911-3 and at BESSY beamline BL14.1.

  15. Fast Method for Computing Chemical Potentials and Liquid-Liquid Phase Equilibria of Macromolecular Solutions.

    Science.gov (United States)

    Qin, Sanbo; Zhou, Huan-Xiang

    2016-08-25

    Chemical potential is a fundamental property for determining thermodynamic equilibria involving exchange of molecules, such as between two phases of molecular systems. Previously, we developed the fast Fourier transform (FFT)-based method for Modeling Atomistic Protein-crowder interactions (FMAP) to calculate excess chemical potentials according to the Widom insertion. Intermolecular interaction energies were expressed as correlation functions and evaluated via FFT. Here, we extend this method to calculate liquid-liquid phase equilibria of macromolecular solutions. Chemical potentials are calculated by FMAP over a wide range of molecular densities, and the condition for coexistence of low- and high-density phases is determined by the Maxwell equal-area rule. When benchmarked on Lennard-Jones fluids, our method produces an accurate phase diagram at 18% of the computational cost of the current best method. Importantly, the gain in computational speed increases dramatically as the molecules become more complex, leading to many orders of magnitude in speed up for atomistically represented proteins. We demonstrate the power of FMAP by reporting the first results for the liquid-liquid coexistence curve of γII-crystallin represented at the all-atom level. Our method may thus open the door to accurate determination of phase equilibria for macromolecular mixtures such as protein-protein mixtures and protein-RNA mixtures, that are known to undergo liquid-liquid phase separation, both in vitro and in vivo.

  16. Assessing physio-macromolecular effects of lactic acid on Zygosaccharomyces bailii cells during microaerobic fermentation.

    Science.gov (United States)

    Kuanyshev, Nurzhan; Ami, Diletta; Signori, Lorenzo; Porro, Danilo; Morrissey, John P; Branduardi, Paola

    2016-08-01

    The ability of Zygosaccharomyces bailii to grow at low pH and in the presence of considerable amounts of weak organic acids, at lethal condition for Saccharomyces cerevisiae, increased the interest in the biotechnological potential of the yeast. To understand the mechanism of tolerance and growth effect of weak acids on Z. bailii, we evaluated the physiological and macromolecular changes of the yeast exposed to sub lethal concentrations of lactic acid. Lactic acid represents one of the important commodity chemical which can be produced by microbial fermentation. We assessed physiological effect of lactic acid by bioreactor fermentation using synthetic media at low pH in the presence of lactic acid. Samples collected from bioreactors were stained with propidium iodide (PI) which revealed that, despite lactic acid negatively influence the growth rate, the number of PI positive cells is similar to that of the control. Moreover, we have performed Fourier Transform Infra-Red (FTIR) microspectroscopy analysis on intact cells of the same samples. This technique has been never applied before to study Z. bailii under this condition. The analyses revealed lactic acid induced macromolecular changes in the overall cellular protein secondary structures, and alterations of cell wall and membrane physico-chemical properties.

  17. Resolving macromolecular structures from electron cryo-tomography data using subtomogram averaging in RELION.

    Science.gov (United States)

    Bharat, Tanmay A M; Scheres, Sjors H W

    2016-11-01

    Electron cryo-tomography (cryo-ET) is a technique that is used to produce 3D pictures (tomograms) of complex objects such as asymmetric viruses, cellular organelles or whole cells from a series of tilted electron cryo-microscopy (cryo-EM) images. Averaging of macromolecular complexes found within tomograms is known as subtomogram averaging, and this technique allows structure determination of macromolecular complexes in situ. Subtomogram averaging is also gaining in popularity for the calculation of initial models for single-particle analysis. We describe herein a protocol for subtomogram averaging from cryo-ET data using the RELION software (http://www2.mrc-lmb.cam.ac.uk/relion). RELION was originally developed for cryo-EM single-particle analysis, and the subtomogram averaging approach presented in this protocol has been implemented in the existing workflow for single-particle analysis so that users may conveniently tap into existing capabilities of the RELION software. We describe how to calculate 3D models for the contrast transfer function (CTF) that describe the transfer of information in the imaging process, and we illustrate the results of classification and subtomogram averaging refinement for cryo-ET data of purified hepatitis B capsid particles and Saccharomyces cerevisiae 80S ribosomes. Using the steps described in this protocol, along with the troubleshooting and optimization guidelines, high-resolution maps can be obtained in which secondary structure elements are resolved subtomogram.

  18. Force interacts with macromolecular structure in activation of TGF-β.

    Science.gov (United States)

    Dong, Xianchi; Zhao, Bo; Iacob, Roxana E; Zhu, Jianghai; Koksal, Adem C; Lu, Chafen; Engen, John R; Springer, Timothy A

    2017-02-02

    Integrins are adhesion receptors that transmit force across the plasma membrane between extracellular ligands and the actin cytoskeleton. In activation of the transforming growth factor-β1 precursor (pro-TGF-β1), integrins bind to the prodomain, apply force, and release the TGF-β growth factor. However, we know little about how integrins bind macromolecular ligands in the extracellular matrix or transmit force to them. Here we show how integrin αVβ6 binds pro-TGF-β1 in an orientation biologically relevant for force-dependent release of TGF-β from latency. The conformation of the prodomain integrin-binding motif differs in the presence and absence of integrin binding; differences extend well outside the interface and illustrate how integrins can remodel extracellular matrix. Remodelled residues outside the interface stabilize the integrin-bound conformation, adopt a conformation similar to earlier-evolving family members, and show how macromolecular components outside the binding motif contribute to integrin recognition. Regions in and outside the highly interdigitated interface stabilize a specific integrin/pro-TGF-β orientation that defines the pathway through these macromolecules which actin-cytoskeleton-generated tensile force takes when applied through the integrin β-subunit. Simulations of force-dependent activation of TGF-β demonstrate evolutionary specializations for force application through the TGF-β prodomain and through the β- and not α-subunit of the integrin.

  19. Macromolecular Crowding Studies of Amino Acids Using NMR Diffusion Measurements and Molecular Dynamics Simulations

    Directory of Open Access Journals (Sweden)

    Amninder S Virk

    2015-02-01

    Full Text Available Molecular crowding occurs when the total concentration of macromolecular species in a solution is so high that a considerable proportion of the volume is physically occupied and therefore not accessible to other molecules. This results in significant changes in the solution properties of the molecules in such systems. Macromolecular crowding is ubiquitous in biological systems due to the generally high intracellular protein concentrations. The major hindrance to understanding crowding is the lack of direct comparison of experimental data with theoretical or simulated data. Self-diffusion is sensitive to changes in the molecular weight and shape of the diffusing species, and the available diffusion space (i.e., diffusive obstruction. Consequently, diffusion measurements are a direct means for probing crowded systems including the self-association of molecules. In this work, nuclear magnetic resonance measurements of the self-diffusion of four amino acids (glycine, alanine, valine and phenylalanine up to their solubility limit in water were compared directly with molecular dynamics simulations. The experimental data were then analyzed using various models of aggregation and obstruction. Both experimental and simulated data revealed that the diffusion of both water and the amino acids were sensitive to the amino acid concentration. The direct comparison of the simulated and experimental data afforded greater insights into the aggregation and obstruction properties of each amino acid.

  20. Geologic Storage of CO2: Leakage Pathways and Environmental Risks

    Science.gov (United States)

    Celia, M. A.; Peters, C. A.; Bachu, S.

    2002-05-01

    Geologic storage of CO2 appears to be an attractive option for carbon mitigation because it offers sufficient capacity to solve the problem, and it can be implemented with existing technology. Among the list of options for storage sites, depleted hydrocarbon reservoirs and deep saline aquifers are two major categories. While injection into hydrocarbon reservoirs offers immediate possibilities, especially in the context of enhanced oil recovery, it appears that deep saline aquifers provide the extensive capacity necessary to solve the problem over the decade to century time scale. Capacity and technology argue favorably for this option, but remaining obstacles to implementation include capture technologies, overall economic considerations, and potential environmental consequences of the injection. Of these, the environmental questions may be most difficult to solve. Experience from CO2 floods for enhanced oil recovery and from CO2 and acid gas disposal operations indicates that geological storage of CO2 is safe over the short term for comparatively small amounts of CO2. However, there is no experience to date regarding the long-term fate and safety of the large volumes of CO2 that must be injected to significantly reduce atmospheric emissions. In order to make proper evaluation of environmental risks, the full range of possible environmental consequences must be considered. Most of these environmental concerns involve migration and leakage of CO2 into shallow portions of the subsurface and eventually into the atmosphere. In shallow subsurface zones, elevated levels of carbon dioxide can cause pH changes, leading to possible mobilization of ground-water contaminants including metals. In the unsaturated zone, vegetation can be adversely affected, as can other ecosystem components. At the land surface, elevated levels of CO2 can lead to asphyxiation in humans and other animals. And finally, in the atmosphere, CO2 that leaks from underground diminishes the effectiveness

  1. MX1: a bending-magnet crystallography beamline serving both chemical and macromolecular crystallography communities at the Australian Synchrotron

    Energy Technology Data Exchange (ETDEWEB)

    Cowieson, Nathan Philip; Aragao, David; Clift, Mark; Ericsson, Daniel J.; Gee, Christine; Harrop, Stephen J.; Mudie, Nathan; Panjikar, Santosh; Price, Jason R.; Riboldi-Tunnicliffe, Alan; Williamson, Rachel; Caradoc-Davies, Tom, E-mail: tom.caradoc-davies@synchrotron.org.au [Australian Synchrotron, 800 Blackburn Road, Clayton, Victoria 3168 (Australia)

    2015-01-01

    The macromolecular crystallography beamline MX1 at the Australian Synchrotron is described. MX1 is a bending-magnet crystallography beamline at the 3 GeV Australian Synchrotron. The beamline delivers hard X-rays in the energy range from 8 to 18 keV to a focal spot at the sample position of 120 µm FWHM. The beamline endstation and ancillary equipment facilitate local and remote access for both chemical and biological macromolecular crystallography. Here, the design of the beamline and endstation are discussed. The beamline has enjoyed a full user program for the last seven years and scientific highlights from the user program are also presented.

  2. Effect of STI-induced mechanical stress on leakage current in deep submicron CMOS devices

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The shallow trench isolation (STI) induced mechanical stress significantly affects the CMOS device off-state leakage behaviour. In this paper, we designed two types of devices to investigate this effect, and all leakage components,including sub-threshold leakage (Isub), gate-induced-drain-leakage (IGIDL), gate edge-direct-tunnelling leakage (IEDT) and band-to-band-tunnelling leakage (IBTBT) were analysed. For NMOS, Isub can be reduced due to the mechanical stress induced higher boron concentration in well region. However, the GIDL component increases simultaneously as a result of the high well concentration induced drain-to-well depletion layer narrowing as well as the shrinkage of the energy gap. For PMOS, the only mechanical stress effect on leakage current is the energy gap narrowing induced GIDL increase.

  3. Monetizing Leakage Risk of Geologic CO2 Storage using Wellbore Permeability Frequency Distributions

    Science.gov (United States)

    Bielicki, Jeffrey; Fitts, Jeffrey; Peters, Catherine; Wilson, Elizabeth

    2013-04-01

    Carbon dioxide (CO2) may be captured from large point sources (e.g., coal-fired power plants, oil refineries, cement manufacturers) and injected into deep sedimentary basins for storage, or sequestration, from the atmosphere. This technology—CO2 Capture and Storage (CCS)—may be a significant component of the portfolio of technologies deployed to mitigate climate change. But injected CO2, or the brine it displaces, may leak from the storage reservoir through a variety of natural and manmade pathways, including existing wells and wellbores. Such leakage will incur costs to a variety of stakeholders, which may affect the desirability of potential CO2 injection locations as well as the feasibility of the CCS approach writ large. Consequently, analyzing and monetizing leakage risk is necessary to develop CCS as a viable technological option to mitigate climate change. Risk is the product of the probability of an outcome and the impact of that outcome. Assessment of leakage risk from geologic CO2 storage reservoirs requires an analysis of the probabilities and magnitudes of leakage, identification of the outcomes that may result from leakage, and an assessment of the expected economic costs of those outcomes. One critical uncertainty regarding the rate and magnitude of leakage is determined by the leakiness of the well leakage pathway. This leakiness is characterized by a leakage permeability for the pathway, and recent work has sought to determine frequency distributions for the leakage permeabilities of wells and wellbores. We conduct a probabilistic analysis of leakage and monetized leakage risk for CO2 injection locations in the Michigan Sedimentary Basin (USA) using empirically derived frequency distributions for wellbore leakage permeabilities. To conduct this probabilistic risk analysis, we apply the RISCS (Risk Interference of Subsurface CO2 Storage) model (Bielicki et al, 2013a, 2012b) to injection into the Mt. Simon Sandstone. RISCS monetizes leakage risk

  4. Simulations of hydraulic fracturing and leakage in sedimentary basins

    Energy Technology Data Exchange (ETDEWEB)

    Lothe, Ane Elisabeth

    2004-01-01

    Hydraulic fracturing and leakage of water through the caprock is described from sedimentary basin over geological time scale. Abnormal pressure accumulations reduce the effective stresses in the underground and trigger the initiation of hydraulic fractures. The major faults in the basin define these pressure compartments. In this Thesis, basin simulations of hydraulic fracturing and leakage have been carried out. A simulator (Pressim) is used to calculate pressure generation and dissipitation between the compartments. The flux between the compartments and not the flow within the compartments is modelled. The Griffith-Coulomb failure criterion determines initial failure at the top structures of overpressured compartments, whereas the frictional sliding criterion is used for reactivation along the same fractures. The minimum horizontal stress is determined from different formulas, and an empirical one seems to give good results compared to measured pressures and minimum horizontal stresses. Simulations have been carried out on two datasets; one covering the Halten Terrace area and one the Tune Field area in the northern North Sea. The timing of hydraulic fracturing and amount of leakage has been quantified in the studies from the Halten Terrace area. This is mainly controlled by the lateral fluid flow and the permeability of the major faults in the basin. Low fault permeability gives early failure, while high fault permeabilities results in no or late hydraulic fracturing and leakage from overpressured parts of the basin. In addition to varying the transmissibility of all faults in a basin, the transmissibility across individual faults can be varied. Increasing the transmissibility across faults is of major importance in overpressured to intermediately pressured areas. However, to obtain change in the flow, a certain pressure difference has to be the situation between the different compartments. The coefficient of internal friction and the coefficient of frictional

  5. Assessment of different dyes used in leakage studies.

    Science.gov (United States)

    Mente, Johannes; Ferk, Stephan; Dreyhaupt, Jens; Deckert, Andreas; Legner, Milos; Staehle, Hans Joerg

    2010-06-01

    The goal of this in vitro study was to identify the most suitable dye for endodontic dye leakage studies, which could be a further step towards standardisation. The root canals of 70 extracted, single-rooted human adult teeth were enlarged to apical size 50 using hand instruments. The teeth were divided into seven groups (n = 10 each), and all root canals were completely filled by injection with one of the following dyes: methylene blue 0.5% and 5%, blue ink, black ink, eosin 5%, basic fuchsin 0.5% and drawing ink. Transverse root sections from the coronal, middle and apical part of the roots were examined, and the percentage of the dentine penetrated by dye was evaluated by software-supported light microscopy. In addition, the range of particle size of drawing ink particles was evaluated. There were conspicuous differences in the relative dye penetration into the root dentine and the penetration behaviour in the different root sections (two-way ANOVA, both p < 0.0001). One dye (drawing ink) penetrated less into the root dentine compared with all the others (p <0.0001). The particle size of this agent (0.1-2 microm) corresponds best with the size range of a representative selection of 21 species of pathogenic endodontic bacteria. Compared to the other dyes tested, drawing ink appears to be superior for use in endodontic dye leakage studies. The penetration behaviour into the root dentine of all the other dyes tested might be one factor that limits the applicability of these dyes in dye leakage studies.

  6. Power Beaming Leakage Radiation as a SETI Observable

    Science.gov (United States)

    Benford, James N.; Benford, Dominic J.

    2016-07-01

    The most observable leakage radiation from an advanced civilization may well be from the use of power beaming to transfer energy and accelerate spacecraft. Applications suggested for power beaming involve launching spacecraft to orbit, raising satellites to a higher orbit, and interplanetary concepts involving space-to-space transfers of cargo or passengers. We also quantify beam-driven launch to the outer solar system, interstellar precursors, and ultimately starships. We estimate the principal observable parameters of power beaming leakage. Extraterrestrial civilizations would know their power beams could be observed, and so could put a message on the power beam and broadcast it for our receipt at little additional energy or cost. By observing leakage from power beams we may find a message embedded on the beam. Recent observations of the anomalous star KIC 8462852 by the Allen Telescope Array (ATA) set some limits on extraterrestrial power beaming in that system. We show that most power beaming applications commensurate with those suggested for our solar system would be detectable if using the frequency range monitored by the ATA, and so the lack of detection is a meaningful, if modest, constraint on extraterrestrial power beaming in that system. Until more extensive observations are made, the limited observation time and frequency coverage are not sufficiently broad in frequency and duration to produce firm conclusions. Such beams would be visible over large interstellar distances. This implies a new approach to the SETI search: instead of focusing on narrowband beacon transmissions generated by another civilization, look for more powerful beams with much wider bandwidth. This requires a new approach for their discovery by telescopes on Earth. Further studies of power beaming applications should be performed, potentially broadening the parameter space of the observable features that we have discussed here.

  7. Air Leakage and Air Transfer Between Garage and Living Space

    Energy Technology Data Exchange (ETDEWEB)

    Rudd, A.

    2014-09-01

    This research project focused on evaluation of air transfer between the garage and living space in a single-family detached home constructed by a production homebuilder in compliance with the 2009 International Residential Code and the 2009 International Energy Conservation Code. The project gathered important information about the performance of whole-building ventilation systems and garage ventilation systems as they relate to minimizing flow of contaminated air from garage to living space. A series of 25 multi-point fan pressurization tests and additional zone pressure diagnostic testing characterized the garage and house air leakage, the garage-to-house air leakage, and garage and house pressure relationships to each other and to outdoors using automated fan pressurization and pressure monitoring techniques. While the relative characteristics of this house may not represent the entire population of new construction configurations and air tightness levels (house and garage) throughout the country, the technical approach was conservative and should reasonably extend the usefulness of the results to a large spectrum of house configurations from this set of parametric tests in this one house. Based on the results of this testing, the two-step garage-to-house air leakage test protocol described above is recommended where whole-house exhaust ventilation is employed. For houses employing whole-house supply ventilation (positive pressure) or balanced ventilation (same pressure effect as the Baseline condition), adherence to the EPA Indoor airPLUS house-to-garage air sealing requirements should be sufficient to expect little to no garage-to-house air transfer.

  8. An Improved Method for Preventing Data Leakage in an Organization

    Directory of Open Access Journals (Sweden)

    Neetu Bose

    2016-04-01

    Full Text Available Data is one of the most important assets an organisation has since it denes each organisations unique- ness.It includes data on members and prospects, their inter- ests and purchases, your events, speakers, your content, social media, press, your staff, budget, strategic plan, and much more. As organizations open their doors to employees, part- ners, customers and suppliers to provide deeper access to sensitive information, the risk sassociated with business increase. Now, more than ever, within creasing threats of cyber terrorism, cor- porate governance issues, fraud, and identity theft, the need for securing corporate information has become paramount. Informa- tion theft is not just about external hackers and unauthorized external users stealing your data, it is also about managing internal employees and even contractors who may be working within your organization for short periods of time. Adding to the challenge of securing information is the increasing push for corporate governance and adherence to legislative or regulatory requirements. Failure to comply and provide privacy, audit and internal controls could result in penalties ranging from large nes to jail terms. Non-compliance can result in not only potential implications for executives, but also possible threats to the viability of a corporation. Insiders too represent a sign cant risk to data security. The task of detecting malicious insiders is very challenging as the methods of deception become more and more sophisticated. There are various solutions present to avoid data leakage. Data leakage detection, prevention (DLPM and monitoring solutions became an inherent component of the organizations security suite.DLP solutions monitors sensitive data when at rest, in motion, or in use and enforce the organizational data protection policy.These solutions focus mainly on the data and its sensitivity level, and on preventing it from reaching an unauthorized person. They ignore the fact

  9. Low Leakage Turbine Shaft Seals for Advanced Combined Cycle Systems.

    Science.gov (United States)

    1984-11-01

    leakage causes virtually all of the makeup feedwater requirements and consequent requirements for evaporators, storage tanks, DI bottle sizes, and...conservative approach and thereby maximizing reliability potential. The face seal configuration features a (rotating) runner which is virtually ...STANDARD, 196 A -I--~ ~ FD In~IU1 ~ - - - K ’ ,t ~N _i.SA 4 0 0 0 di- AULAS -w - W-6 4. . 0I - I 0 i C- A L; u V) c, 3>. _ I IL’C a rx i.- V

  10. Effect of Surface Treatments on Leakage of Zirconium Oxide Ceramics

    OpenAIRE

    Göknil Alkan Demetoğlu; Mustafa Zortuk

    2016-01-01

    Objective: The aim of this pilot study was to compare the effects of pretreatments on leakage of zirconia ceramics. Materials and Methods: The speciments divided into 6 groups that were subsequently treated as follows: group 1, no treatment (control); group 2, the ceramic surfaces were airborne-particle abraded with 110 μm aluminum-oxide (Al2O3) particles; group 3, after abrasion of the surfaces with 110 μm Al2O3 particles, silica coating using 30 μm (Al2O3) particles modified by silica (r...

  11. Measurement of LINAC 90 degrees head leakage radiation TVL values.

    Science.gov (United States)

    Li, Zuofeng; Mutic, Sasa; Low, Daniel

    2006-09-01

    One of the key components in modern LINAC room shielding design is the amount of 90 degrees head leakage radiation levels. With the general clinical acceptance of intensity-modulated radiation therapy (IMRT) technique, accurate knowledge of this quantity has become even more important. Measurement of 90 degrees head leakage radiation of medical linear accelerators can be technically challenging due to the low dose rate causing poor signal-to-noise ratios in most detectors. 90 degrees leakage tenth-value layer (TVL) values in concrete have not been reported for the Elekta linear accelerators. This report describes our measurements of 90 degrees leakage TVL values for 6, 10, and 18 MV x-ray beams for an Elekta Precise Treatment System. A large-volume (1000 cm3) unpressurized ionization chamber and a high sensitivity electrometer, together with a separate chamber bias power supply, were used in these measurements in order to maximize the signal-to-noise ratio. A lead enclosure, of minimum thickness 10 cm, was constructed inside the treatment room to house the ion chamber to reduce the influence of room-scattered radiation. A square aperture of 10 X 10 cm2 area was left in the shield and aimed towards the accelerator head. Measurements were performed with the chamber placed at approximately 2 m from the accelerator isocenter. Concrete slabs with individual dimensions of approximately 40 X 40 cm2 cross-sectional area and 5 cm thickness were placed between the accelerator head and the ion chamber for these measurements. The measurements were performed with total concrete thickness of up to 80 cm, so that values up to the third TVL were measured. These measurements showed thatthe first concrete TVL values are 22, 23, and 28 cm (8.6, 9.1, and 10.5 in.) for 6, 10, and 18 MV beams, while the average of the first 3 TVL's were 25, 26, and 29 cm (9.9, 10.2, and 11.5 in.). Measured values agreed to within 10% of previously reported values for Varian linear accelerators for

  12. Leakage investigation at Shalamar Garden, Lahore using radioisotopes

    Energy Technology Data Exchange (ETDEWEB)

    Hussain, S.D.; Mustafa, N.; Khan, N.A. (Pakistan Inst. of Nuclear Science and Technology, Rawalpindi)

    1982-02-01

    A sealed caesium-137 radiation source and 73 injections of sodium-24 in water soluble form have been successfully employed to detect leakage points and determine the layout pattern of a terracotta pipeline grid feeding the decorative fountains of the central tank in the middle terrace of Shalamar Garden, Lahore. The pipeline system is about 350 years old and no drawing or layout plan was available before the studies. The present investigation is an effort to help restore the original historic water supply system.

  13. Application Of The Climafor Baseline To Determine Leakage: TheCase Of Scolel Te.

    Energy Technology Data Exchange (ETDEWEB)

    De Jong, B.H.J.; Bazan, E. Esquivel; Quechulpa Montalvo, S.

    2007-06-01

    The acceptance of forestry-based project activities tomitigate greenhouse gases emissions has been subjected to a number ofmethodological questions to be answered, of which the most challengingare baseline establishment and identification of and measuring leakage.Here we pose hypotheses for and quantify leakage of the Scolel Te projectin Chiapas, Mexico. In this project small-scale farmers are implementingforestry, agroforestry, and forest conservation activities, with carbonsequestration as one of the goals. The main leakage monitoring domain isdefined as the area owned by the participating farmers or communitiesoutside the area where the specific project activities take place. Thenull-hypothesis (no leakage) is that non-project land owned by the farmeror community will experience the same carbon stock changes as predictedby the regional baseline, specifically developed for the project. Firstwe assessed the most likely causes and sources of leakage that may occurin the project. From this analysis, one type of leakage seems to beimportant, i.e., activity shifting. Second we estimated the leakage of asample of participating farmers and communities. Actual land use was thencompared with expected land use derived from the baseline. The Plan Vivoof each participant, complemented with readily available tools toidentify the main sources and drivers of leakage are used to developsimple leakage assessment procedures, as demonstrated in this paper.Negative leakage was estimated to be negligible in this study.Incorporating these procedures already in the project planning stage willreduce the uncertainties related to the actual carbon mitigationpotential of any forestry project.

  14. Proceedings of a one-week course on exploiting anomalous scattering in macromolecular structure determination (EMBO'07)

    Energy Technology Data Exchange (ETDEWEB)

    Weiss, M.S.; Shepard, W.; Dauter, Z.; Leslie, A.; Diederichs, K.; Evans, G.; Svensson, O.; Schneider, T.; Bricogne, G.; Dauter, Z.; Flensburg, C.; Terwilliger, T.; Lamzin, V.; Leslie, A.; Kabsch, W.; Flensburg, C.; Terwilliger, T.; Lamzin, V.; Read, R.; Panjikar, S.; Pannu, N.S.; Dauter, Z.; Weiss, M.S.; McSweeney, S

    2007-07-01

    This course, which was directed to young scientists, illustrated both theoretical and practical aspects of macromolecular crystal structure solution using synchrotron radiation. Some software dedicated to data collection, processing and analysis were presented. This document gathers only the slides of the presentations.

  15. Force Spectroscopy of Individual Stimulus-Responsive Poly(ferrocenyldimethylsilane) Chains: Towards a Redox-Driven Macromolecular Motor

    NARCIS (Netherlands)

    Zou, Shan; Hempenius, Mark A.; Schönherr, Holger; Vancso, G. Julius

    2006-01-01

    Progress in the development of a redox-driven macromolecular motor and the characterization of its redox-mechanical cycle using electrochemical AFM-based single-molecule force spectroscopy (SMFS) is described. The elasticities of individual neutral and oxidized poly(ferrocenyldimethylsilane) (PFS) m

  16. Lipase-catalyzed Regioselective Synthesis of Vinyl Ester Derivatives of Thiamphenicol: Novel Thiamphenicol Monomers for Preparation of Macromolecular Antibiotic

    Institute of Scientific and Technical Information of China (English)

    Yu Zhen SHI; Zhi Chun CHEN; Na WANG; Qi WU; Xian Fu LIN

    2005-01-01

    Three polymerizable vinyl thiamphenicol esters with different acyl donor carbon chain length (C4, C6, C10) were regioselectivly synthesized by Lipozyme(R) (immobilized from mucor miehei) in acetone at 50 ℃ for 12 h to give 73%, 81%, 63% yield, respectively. The products were valuable monomers for preparation of macromolecular antibiotic.

  17. Macromolecular crowding meets oxygen tension in human mesenchymal stem cell culture - A step closer to physiologically relevant in vitro organogenesis

    Science.gov (United States)

    Cigognini, Daniela; Gaspar, Diana; Kumar, Pramod; Satyam, Abhigyan; Alagesan, Senthilkumar; Sanz-Nogués, Clara; Griffin, Matthew; O'Brien, Timothy; Pandit, Abhay; Zeugolis, Dimitrios I.

    2016-08-01

    Modular tissue engineering is based on the cells’ innate ability to create bottom-up supramolecular assemblies with efficiency and efficacy still unmatched by man-made devices. Although the regenerative potential of such tissue substitutes has been documented in preclinical and clinical setting, the prolonged culture time required to develop an implantable device is associated with phenotypic drift and/or cell senescence. Herein, we demonstrate that macromolecular crowding significantly enhances extracellular matrix deposition in human bone marrow mesenchymal stem cell culture at both 20% and 2% oxygen tension. Although hypoxia inducible factor - 1α was activated at 2% oxygen tension, increased extracellular matrix synthesis was not observed. The expression of surface markers and transcription factors was not affected as a function of oxygen tension and macromolecular crowding. The multilineage potential was also maintained, albeit adipogenic differentiation was significantly reduced in low oxygen tension cultures, chondrogenic differentiation was significantly increased in macromolecularly crowded cultures and osteogenic differentiation was not affected as a function of oxygen tension and macromolecular crowding. Collectively, these data pave the way for the development of bottom-up tissue equivalents based on physiologically relevant developmental processes.

  18. Probing the Interplay of Size, Shape, and Solution Environment in Macromolecular Diffusion Using a Simple Refraction Experiment

    Science.gov (United States)

    Mankidy, Bijith D.; Coutinho, Cecil A.; Gupta, Vinay K.

    2010-01-01

    The diffusion coefficient of polymers is a critical parameter in biomedicine, catalysis, chemical separations, nanotechnology, and other industrial applications. Here, measurement of macromolecular diffusion in solutions is described using a visually instructive, undergraduate-level optical refraction experiment based on Weiner's method. To…

  19. Reliable and efficient solution of genome-scale models of Metabolism and macromolecular Expression

    Science.gov (United States)

    Ma, Ding; Yang, Laurence; Fleming, Ronan M. T.; Thiele, Ines; Palsson, Bernhard O.; Saunders, Michael A.

    2017-01-01

    Constraint-Based Reconstruction and Analysis (COBRA) is currently the only methodology that permits integrated modeling of Metabolism and macromolecular Expression (ME) at genome-scale. Linear optimization computes steady-state flux solutions to ME models, but flux values are spread over many orders of magnitude. Data values also have greatly varying magnitudes. Standard double-precision solvers may return inaccurate solutions or report that no solution exists. Exact simplex solvers based on rational arithmetic require a near-optimal warm start to be practical on large problems (current ME models have 70,000 constraints and variables and will grow larger). We have developed a quadruple-precision version of our linear and nonlinear optimizer MINOS, and a solution procedure (DQQ) involving Double and Quad MINOS that achieves reliability and efficiency for ME models and other challenging problems tested here. DQQ will enable extensive use of large linear and nonlinear models in systems biology and other applications involving multiscale data.

  20. Integration and global analysis of isothermal titration calorimetry data for studying macromolecular interactions.

    Science.gov (United States)

    Brautigam, Chad A; Zhao, Huaying; Vargas, Carolyn; Keller, Sandro; Schuck, Peter

    2016-05-01

    Isothermal titration calorimetry (ITC) is a powerful and widely used method to measure the energetics of macromolecular interactions by recording a thermogram of differential heating power during a titration. However, traditional ITC analysis is limited by stochastic thermogram noise and by the limited information content of a single titration experiment. Here we present a protocol for bias-free thermogram integration based on automated shape analysis of the injection peaks, followed by combination of isotherms from different calorimetric titration experiments into a global analysis, statistical analysis of binding parameters and graphical presentation of the results. This is performed using the integrated public-domain software packages NITPIC, SEDPHAT and GUSSI. The recently developed low-noise thermogram integration approach and global analysis allow for more precise parameter estimates and more reliable quantification of multisite and multicomponent cooperative and competitive interactions. Titration experiments typically take 1-2.5 h each, and global analysis usually takes 10-20 min.

  1. A mixed method for measuring low-frequency acoustic properties of macromolecular materials

    Institute of Scientific and Technical Information of China (English)

    LIU; Hongwei; YAO; Lei; ZHAO; Hong; ZHANG; Jichuan; XUE; Zhaohong

    2006-01-01

    A mixed method for measuring low-frequency acoustic properties of macromolecular materials is presented.The dynamic mechanical parameters of materials are first measured by using Dynamic Mechanical Thermal Apparatus(DMTA) at low frequencies,usually less than 100 Hz; then based on the Principles of Time-Temperature Super position (TTS),these parameters are extended to the frequency range that acousticians are concerned about,usually from hundreds to thousands of hertz; finally the extended dynamic mechanical parameters are transformed into acoustic parameters with the help of acoustic measurement and inverse analysis.To test the feasibility and accuracy,we measure a kind of rubber sample in DMTA and acquire the basic acoustic parameters of the sample by using this method.While applying the basic parameters to calculating characteristics of the sample in acoustic pipe,a reasonable agreement of sound absorption coefficients is obtained between the calculations and measurements in the acoustic pipe.

  2. Phenix - a comprehensive python-based system for macromolecular structure solution

    Energy Technology Data Exchange (ETDEWEB)

    Terwilliger, Thomas C [Los Alamos National Laboratory; Hung, Li - Wei [Los Alamos National Laboratory; Adams, Paul D [UC BERKELEY; Afonine, Pavel V [UC BERKELEY; Bunkoczi, Gabor [UNIV OF CAMBRIDGE; Chen, Vincent B [DUKE UNIV; Davis, Ian [DUKE UNIV; Echols, Nathaniel [LBNL; Headd, Jeffrey J [DUKE UNIV; Grosse Kunstleve, Ralf W [LBNL; Mccoy, Airlie J [UNIV OF CAMBRIDGE; Moriarty, Nigel W [LBNL; Oeffner, Robert [UNIV OF CAMBRIDGE; Read, Randy J [UNIV OF CAMBRIDGE; Richardson, David C [DUKE UNIV; Richardson, Jane S [DUKE UNIV; Zwarta, Peter H [LBNL

    2009-01-01

    Macromolecular X-ray crystallography is routinely applied to understand biological processes at a molecular level. However, significant time and effort are still required to solve and complete many of these structures because of the need for manual interpretation of complex numerical data using many software packages, and the repeated use of interactive three-dimensional graphics. Phenix has been developed to provide a comprehensive system for crystallographic structure solution with an emphasis on automation of all procedures. This has relied on the development of algorithms that minimize or eliminate subjective input, the development of algorithms that automate procedures that are traditionally performed by hand, and finally the development of a framework that allows a tight integration between the algorithms.

  3. Recent Major Improvements to the ALS Sector 5 MacromolecularCrystallography Beamlines

    Energy Technology Data Exchange (ETDEWEB)

    Morton, Simon A.; Glossinger, James; Smith-Baumann, Alexis; McKean, John P.; Trame, Christine; Dickert, Jeff; Rozales, Anthony; Dauz,Azer; Taylor, John; Zwart, Petrus; Duarte, Robert; Padmore, Howard; McDermott, Gerry; Adams, Paul

    2007-07-01

    Although the Advanced Light Source (ALS) was initially conceived primarily as a low energy (1.9GeV) 3rd generation source of VUV and soft x-ray radiation it was realized very early in the development of the facility that a multipole wiggler source coupled with high quality, (brightness preserving), optics would result in a beamline whose performance across the optimal energy range (5-15keV) for macromolecular crystallography (MX) would be comparable to, or even exceed, that of many existing crystallography beamlines at higher energy facilities. Hence, starting in 1996, a suite of three beamlines, branching off a single wiggler source, was constructed, which together formed the ALS Macromolecular Crystallography Facility. From the outset this facility was designed to cater equally to the needs of both academic and industrial users with a heavy emphasis placed on the development and introduction of high throughput crystallographic tools, techniques, and facilities--such as large area CCD detectors, robotic sample handling and automounting facilities, a service crystallography program, and a tightly integrated, centralized, and highly automated beamline control environment for users. This facility was immediately successful, with the primary Multiwavelength Anomalous Diffraction beamline (5.0.2) in particular rapidly becoming one of the foremost crystallographic facilities in the US--responsible for structures such as the 70S ribosome. This success in-turn triggered enormous growth of the ALS macromolecular crystallography community and spurred the development of five additional ALS MX beamlines all utilizing the newly developed superconducting bending magnets ('superbends') as sources. However in the years since the original Sector 5.0 beamlines were built the performance demands of macromolecular crystallography users have become ever more exacting; with growing emphasis placed on studying larger complexes, more difficult structures, weakly diffracting or

  4. Syntheses of Macromolecular Ruthenium Compounds: A New Approach for the Search of Anticancer Drugs

    Directory of Open Access Journals (Sweden)

    Andreia Valente

    2014-03-01

    Full Text Available The continuous rising of the cancer patient death rate undoubtedly shows the pressure to find more potent and efficient drugs than those in clinical use. These agents only treat a narrow range of cancer conditions with limited success and are associated with serious side effects caused by the lack of selectivity. In this frame, innovative syntheses approaches can decisively contribute to the success of “smart compounds” that might be only selective and/or active towards the cancer cells, sparing the healthy ones. In this scope, ruthenium chemistry is a rising field for the search of proficient metallodrugs by the use of macromolecular ruthenium complexes (dendrimers and dendronized polymers, coordination-cage and protein conjugates, nanoparticles and polymer-“ruthenium-cyclopentadienyl” conjugates that can take advantage of the singularities of tumor cells (vs. healthy cells.

  5. Site-selective electroless nickel plating on patterned thin films of macromolecular metal complexes.

    Science.gov (United States)

    Kimura, Mutsumi; Yamagiwa, Hiroki; Asakawa, Daisuke; Noguchi, Makoto; Kurashina, Tadashi; Fukawa, Tadashi; Shirai, Hirofusa

    2010-12-01

    We demonstrate a simple route to depositing nickel layer patterns using photocross-linked polymer thin films containing palladium catalysts, which can be used as adhesive interlayers for fabrication of nickel patterns on glass and plastic substrates. Electroless nickel patterns can be obtained in three steps: (i) the pattern formation of partially quaterized poly(vinyl pyridine) by UV irradiation, (ii) the formation of macromolecular metal complex with palladium, and (iii) the nickel metallization using electroless plating bath. Metallization is site-selective and allows for a high resolution. And the resulting nickel layered structure shows good adhesion with glass and plastic substrates. The direct patterning of metallic layers onto insulating substrates indicates a great potential for fabricating micro/nano devices.

  6. Phase transitions of macromolecular microsphere composite hydrogels based on the stochastic Cahn–Hilliard equation

    Energy Technology Data Exchange (ETDEWEB)

    Li, Xiao, E-mail: lixiao1228@163.com; Ji, Guanghua, E-mail: ghji@bnu.edu.cn; Zhang, Hui, E-mail: hzhang@bnu.edu.cn

    2015-02-15

    We use the stochastic Cahn–Hilliard equation to simulate the phase transitions of the macromolecular microsphere composite (MMC) hydrogels under a random disturbance. Based on the Flory–Huggins lattice model and the Boltzmann entropy theorem, we develop a reticular free energy suit for the network structure of MMC hydrogels. Taking the random factor into account, with the time-dependent Ginzburg-Landau (TDGL) mesoscopic simulation method, we set up a stochastic Cahn–Hilliard equation, designated herein as the MMC-TDGL equation. The stochastic term in the equation is constructed appropriately to satisfy the fluctuation-dissipation theorem and is discretized on a spatial grid for the simulation. A semi-implicit difference scheme is adopted to numerically solve the MMC-TDGL equation. Some numerical experiments are performed with different parameters. The results are consistent with the physical phenomenon, which verifies the good simulation of the stochastic term.

  7. Functionalization of Planet-Satellite Nanostructures Revealed by Nanoscopic Localization of Distinct Macromolecular Species

    KAUST Repository

    Rossner, Christian

    2016-09-26

    The development of a straightforward method is reported to form hybrid polymer/gold planet-satellite nanostructures (PlSNs) with functional polymer. Polyacrylate type polymer with benzyl chloride in its backbone as a macromolecular tracer is synthesized to study its localization within PlSNs by analyzing the elemental distribution of chlorine. The functionalized nanohybrid structures are analyzed by scanning transmission electron microscopy, electron energy loss spectroscopy, and spectrum imaging. The results show that the RAFT (reversible addition-fragmentation chain transfer) polymers\\' sulfur containing end groups are colocalized at the gold cores, both within nanohybrids of simple core-shell morphology and within higher order PlSNs, providing microscopic evidence for the affinity of the RAFT group toward gold surfaces. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA., Weinheim.

  8. Mix and Inject: Reaction Initiation by Diffusion for Time-Resolved Macromolecular Crystallography

    Directory of Open Access Journals (Sweden)

    Marius Schmidt

    2013-01-01

    Full Text Available Time-resolved macromolecular crystallography unifies structure determination with chemical kinetics, since the structures of transient states and chemical and kinetic mechanisms can be determined simultaneously from the same data. To start a reaction in an enzyme, typically, an initially inactive substrate present in the crystal is activated. This has particular disadvantages that are circumvented when active substrate is directly provided by diffusion. However, then it is prohibitive to use macroscopic crystals because diffusion times become too long. With small micro- and nanocrystals diffusion times are adequately short for most enzymes and the reaction can be swiftly initiated. We demonstrate here that a time-resolved crystallographic experiment becomes feasible by mixing substrate with enzyme nanocrystals which are subsequently injected into the X-ray beam of a pulsed X-ray source.

  9. Phase behaviour of macromolecular liquid crystalline materials. Computational studies at the molecular level

    CERN Document Server

    Stimson, L M

    2003-01-01

    Molecular simulations provide an increasingly useful insight into the static and dynamic characteristics of materials. In this thesis molecular simulations of macro-molecular liquid crystalline materials are reported. The first liquid crystalline material that has been investigated is a side chain liquid crystal polymer (SCLCP). In this study semi-atomistic molecular dynamics simulations have been conducted at a range of temperatures and an aligning potential has been applied to mimic the effect of a magnetic field. In cooling the SCLCP from an isotropic melt, microphase separation was observed yielding a domain structure. The application of a magnetic field to this structure aligns the domains producing a stable smectic mesophase. This is the first study in which mesophases have been observed using an off-lattice model of a SCLCP. The second material that has been investigated is a dendrimer with terminal mesogenic functionalization. Here, a multi-scale approach has been taken with Monte Carlo studies of a s...

  10. Leakage predictions for Rayleigh-step, helium-purge seals

    Science.gov (United States)

    Proctor, Margaret P.

    1988-01-01

    Rayleigh-step, helium purge, annular shaft seals, studied for use in liquid oxygen turbopumps, generate a hydrodynamic force that enables the seal to follow shaft perturbations. Hence, smaller clearances can be used to reduce seal leakage. FLOWCAL, a computer code developed by Mechanical Technology Incorporated, predicts gas flow rate through an annular seal with an axial pressure gradient. Analysis of a 50-mm Rayleigh-step, helium-purge, annular seal showed the flow rate increased axial pressure gradient, downstream pressure, and eccentricity ratio. Increased inlet temperature reduced leakage. Predictions made at maximum and minimum clearances (due to centrifugal and thermal growths, machining tolerances and + or - 2 percent uncertainty in the clearance measurement) placed wide boundaries on expected flow rates. The widest boundaries were set by thermal growth conditions. Predicted flow rates for a 50-mm Rayleigh-step, helium-purge, annular seal underestimated measured flow rates by three to seven times. However, the analysis did accurately predict flow rates for choked gas flow through annular seals when compared to flow rates measured in two other independent studies.

  11. Secure Mobile Agent from Leakage-Resilient Proxy Signatures

    Directory of Open Access Journals (Sweden)

    Fei Tang

    2015-01-01

    Full Text Available A mobile agent can sign a message in a remote server on behalf of a customer without exposing its secret key; it can be used not only to search for special products or services, but also to make a contract with a remote server. Hence a mobile agent system can be used for electronic commerce as an important key technology. In order to realize such a system, Lee et al. showed that a secure mobile agent can be constructed using proxy signatures. Intuitively, a proxy signature permits an entity (delegator to delegate its signing right to another entity (proxy to sign some specified messages on behalf of the delegator. However, the proxy signatures are often used in scenarios where the signing is done in an insecure environment, for example, the remote server of a mobile agent system. In such setting, an adversary could launch side-channel attacks to exploit some leakage information about the proxy key or even other secret states. The proxy signatures which are secure in the traditional security models obviously cannot provide such security. Based on this consideration, in this paper, we design a leakage-resilient proxy signature scheme for the secure mobile agent systems.

  12. An Advanced Leakage Scheme for Neutrino Treatment in Astrophysical Simulations

    Science.gov (United States)

    Perego, A.; Cabezón, R. M.; Käppeli, R.

    2016-04-01

    We present an Advanced Spectral Leakage (ASL) scheme to model neutrinos in the context of core-collapse supernovae (CCSNe) and compact binary mergers. Based on previous gray leakage schemes, the ASL scheme computes the neutrino cooling rates by interpolating local production and diffusion rates (relevant in optically thin and thick regimes, respectively) separately for discretized values of the neutrino energy. Neutrino trapped components are also modeled, based on equilibrium and timescale arguments. The better accuracy achieved by the spectral treatment allows a more reliable computation of neutrino heating rates in optically thin conditions. The scheme has been calibrated and tested against Boltzmann transport in the context of Newtonian spherically symmetric models of CCSNe. ASL shows a very good qualitative and a partial quantitative agreement for key quantities from collapse to a few hundreds of milliseconds after core bounce. We have proved the adaptability and flexibility of our ASL scheme, coupling it to an axisymmetric Eulerian and to a three-dimensional smoothed particle hydrodynamics code to simulate core collapse. Therefore, the neutrino treatment presented here is ideal for large parameter-space explorations, parametric studies, high-resolution tests, code developments, and long-term modeling of asymmetric configurations, where more detailed neutrino treatments are not available or are currently computationally too expensive.

  13. AN ADVANCED LEAKAGE SCHEME FOR NEUTRINO TREATMENT IN ASTROPHYSICAL SIMULATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Perego, A. [Institut für Kernphysik, Technische Universität Darmstadt, Schlossgartenstraße 2, D-64289 Darmstadt (Germany); Cabezón, R. M. [Physics Department, University of Basel, Klingelbergstrasse 82, CH-4056 Basel (Switzerland); Käppeli, R., E-mail: albino.perego@physik.tu-darmstadt.de [Seminar for Applied Mathematics, ETH Zürich, Rämistrasse 101, 8092 Zürich (Switzerland)

    2016-04-15

    We present an Advanced Spectral Leakage (ASL) scheme to model neutrinos in the context of core-collapse supernovae (CCSNe) and compact binary mergers. Based on previous gray leakage schemes, the ASL scheme computes the neutrino cooling rates by interpolating local production and diffusion rates (relevant in optically thin and thick regimes, respectively) separately for discretized values of the neutrino energy. Neutrino trapped components are also modeled, based on equilibrium and timescale arguments. The better accuracy achieved by the spectral treatment allows a more reliable computation of neutrino heating rates in optically thin conditions. The scheme has been calibrated and tested against Boltzmann transport in the context of Newtonian spherically symmetric models of CCSNe. ASL shows a very good qualitative and a partial quantitative agreement for key quantities from collapse to a few hundreds of milliseconds after core bounce. We have proved the adaptability and flexibility of our ASL scheme, coupling it to an axisymmetric Eulerian and to a three-dimensional smoothed particle hydrodynamics code to simulate core collapse. Therefore, the neutrino treatment presented here is ideal for large parameter-space explorations, parametric studies, high-resolution tests, code developments, and long-term modeling of asymmetric configurations, where more detailed neutrino treatments are not available or are currently computationally too expensive.

  14. Low standby leakage 12T SRAM cell characterisation

    Science.gov (United States)

    Yadav, Arjun; Nakhate, Sangeeta

    2016-09-01

    In this work, a low power and variability-aware static random access memory (SRAM) architecture based on a twelve-transistor (12T) cell is proposed. This cell obtains low static power dissipation due to a parallel global latch (G-latch) and storage latch (S-latch), along with a global wordline (GWL), which offer a high cell ratio and pull-up ratio for reliable read and write operations and a low cell ratio and pull-up ratio during idle mode to reduce the standby power dissipation. In the idle state, only the S-latch stores bits, while the G-latch is isolated from the S-latch and the GWL is deactivated. The leakage power consumption of the proposed SRAM cell is thereby reduced by 38.7% compared to that of the conventional six-transistor (6T) SRAM cell. This paper evaluates the impact of the chip supply voltage and surrounding temperature variations on the standby leakage power and observes considerable improvement in the power dissipation. The read/write access delay, read static noise margin (SNM) and write SNM were evaluated, and the results were compared with those of the standard 6T SRAM cell. The proposed cell, when compared with the existing cell using the Monte Carlo method, shows an appreciable improvement in the standby power dissipation and layout area.

  15. Detection and quantification of methane leakage from landfills

    Energy Technology Data Exchange (ETDEWEB)

    Ljungberg, Sven-Aake; Maartensson, Stig-Goeran (Univ. of Gaevle, Gaevle (Sweden)); Meijer, Jan-Erik; Rosqvist, Haakan (NSR AB, Helsingborg (Sweden))

    2009-03-15

    The purpose of this project was to detect gas leakage and to measure and quantify methane emission from landfills using modern remote sensing techniques. In this project, a handheld laser instrument and an IR camera were used. The overall objective was to develop cost-effective methods for detecting and quantifying methane emissions from landfills. There are many methods available for measuring the methane concentration in air, both from close-up and from long distances. Combined with the use of a tracer gas, the methane emission from entire landfills can be measured relatively accurately. A number of methods are used to detect leakage from parts of landfill surfaces, but there are few methods for quantifying leakage from sub-zones. Field measurements with the laser instrument and the IR camera were carried out at seven Swedish landfills and two landfills in France. The investigated surfaces at the Swedish landfills were divided into different zones, such as top surface, slope, crest and toe of slope. The field measurements in France were taken over entire landfills. The methane emission varied between the different landfills in the project, and also between the different landfill zones. The results from repeated field measurements indicated that a landfill with a final cap and a successful gas recovery system produces barely measurable emissions. The weak points at a landfill are generally slopes, including crests and toes of slopes. Where the covering of the waste is inadequate, leakage often occurs at lift joints and in areas where waste protrudes through the cover. Other weak points are deficiencies in the gas recovery system. Leachate systems can lead landfill gas and thereby cause methane leakage. Along with wind velocity and variations in atmospheric pressure, moisture content in the ground is an important factor that affects methane emissions from landfill surfaces. Results from field measurements of the same feature/surface at different points in time and

  16. Heparin Leakage in Central Venous Catheters by Hemodynamic Transport

    Science.gov (United States)

    Barbour, Michael; McGah, Patrick; Gow, Kenneth; Aliseda, Alberto

    2014-11-01

    Central venous catheters (CVCs), placed in the superior vena cava for hemodialysis, are routinely filled with heparin, an anticoagulant, while not in use to maintain patency and prevent thrombus formation at the catheter tip. However, the heparin-lock procedure places the patient at risk for systemic bleeding incidences, as heparin is known to leak into the blood stream. We propose that the driving mechanism behind heparin leakage is advective-diffusive transport due to the pulsatile blood flow surrounding the catheter tip. This novel hypothesis is based on Planar Laser Induced Fluorescence (PLIF) measurements of heparin transport from a CVC placed inside an in vitro pulsatile flow loop and validated with CFD simulations. The results show an initial, fast (catheter lumen, where concentration is still high, that is insufficient at replenishing the lost heparin at the tip. These results, which estimate leakage rates consistent with published in vivo data, predict that the concentration of heparin at the catheter tip is effectively zero for the majority of the interdialytic phase, rendering the heparin lock ineffective.

  17. Capillary leakage syndrome: a case report and a review.

    Science.gov (United States)

    Garcês, S; Araújo, F; Rego, F; Soares, J L Ducla; Carlos, A G Palma

    2002-12-01

    Capillary leakage Syndrome (CLS) is a rare clinical syndrome, that was first described in 1960, characterized by acute episodes of generalized edema, hemoconcentration, hypoproteinemia and monoclonal gammopathy, in the vast majority of cases. We describe a 39-year-old man with anasarca, bilateral pleural and pericardial effusions, ascites and diffuse alveolo-intersticial edema. Clinical and laboratory findings were consistent with an acute episode of CLS. Treatment with prednisone, furosemide and aminophylline was started, which lead to a gradual improvement in 48 hours. Pathophysiologically there is an increase in capillary permeability with the extravasation of fluid and plasmatic proteins to the extravascular space that can lead to hypovolaemic shock. In the second phase there is a reentry of the fluid overload leading to pulmonary edema. The etiology of this hyperpermeability still remains unclear. The role of cytokines has become central in the comprehension of pathophysiology of CLS. Adhesion molecules are probably also involved in the genesis of capillary leakage. CLS treatment remains empirical. However, at present it seems that the association of steroids with furosemide, aminophylline and terbutaline are capable of controlling the clinical manifestation of the acute episodes in most cases. To our knowledge no prophylatic therapy has clearly proven its efficacy. There are only a few series analyzing the long-term evolution of patients with CLS. Further studies are necessary with the objective to collect enough patients with CLS to observe natural history of the disease and evaluate the efficacy of empiric treatments.

  18. The impact of added insulation on air leakage

    Energy Technology Data Exchange (ETDEWEB)

    Anon

    2002-01-01

    It is relatively easy to calculate the impact on energy consumption when thermal insulation is added to the building envelope. However, other effects such as air leakage through the exterior wall assembly, and the potential for water condensation also have to be considered. By adding insulation to the exterior wall assembly, the temperature gradient of the wall is changed and the risk of condensation is increased, especially if warm, moist indoor air can flow through the wall. The study by Dominique Derome, Paul Fazio and Guylaine Desmarais for the CMHC Research Division, of which this paper is a summary, examined three types of air leakage paths, i.e. long air exfiltration path; concentrated air exfiltration path; and distributed exfiltration path. Experiments involved placing 38 mm rigid extruded polystyrene insulation on the interior side of three wood studs and fiberglass batt insulation wall assemblies, while four other samples had the same 38 mm rigid extruded polystyrene insulation added on the exterior of the assembly over the fiberboard sheathing. Both, warm and cold side additions of rigid foam insulation to the existing assemblies increased thermal performance by 55 per cent. When blown cellulose fibre was used as insulation instead of fibreglass batting, the increase in thermal performance was 66 per cent. Addition of the rigid foam insulation on the warm side tended to increase the effectiveness. For example, moisture content generally did not rise above 25 per cent, whereas it could climb up to 70 per cent when the insulation was added on the cold side.

  19. Credibility Assessments as 'Normative Leakage': Asylum Applications, Gender and Class

    Directory of Open Access Journals (Sweden)

    Hanna Wikström

    2013-10-01

    Full Text Available Based on the assumption that credibility assessments function as 'normative leakage' within the asylum process, we analyse how narratives of gender and class are articulated, rendered meaningful, or silenced in credibility assessments. Two cases concerning male applicants are selected in order to illustrate these processes. In relation to the existing concepts of internal/external credibility, we wish to introduce the concept of social credibility, which focuses on how the assessors read different socio-cultural narratives. While previous research has shown that the postcolonial will to protect women favours women as victims of patriarchal cultures, we wish to point out the continuity of this line of argumentation in relation to male and female applicants by adopting a theoretical generalization: male applicants instead become situated at the other end of the spectrum of postcolonial notions of modernity as non-victims, victims of other circumstances or perpetrators. We argue that these processes are accentuated in relation to credibility assessments. In order to prevent processes of social exclusion and to enhance inclusive practice, authorities need to acknowledge the 'normative leakage' associated with the assessment process.

  20. Angiopoietin-2 is critical for cytokine-induced vascular leakage.

    Directory of Open Access Journals (Sweden)

    Andrew V Benest

    Full Text Available Genetic experiments (loss-of-function and gain-of-function have established the role of Angiopoietin/Tie ligand/receptor tyrosine kinase system as a regulator of vessel maturation and quiescence. Angiopoietin-2 (Ang-2 acts on Tie2-expressing resting endothelial cells as an antagonistic ligand to negatively interfere with the vessel stabilizing effects of constitutive Ang-1/Tie-2 signaling. Ang-2 thereby controls the vascular response to inflammation-inducing as well as angiogenesis-inducing cytokines. This study was aimed at assessing the role of Ang-2 as an autocrine (i.e. endothelial-derived regulator of rapid vascular responses (within minutes caused by permeability-inducing agents. Employing two independent in vivo assays to quantitatively assess vascular leakage (tracheal microsphere assay, 1-5 min and Miles assay, 20 min, the immediate vascular response to histamine, bradykinin and VEGF was analyzed in Ang-2-deficient (Ang-2(-/- mice. In comparison to the wild type control mice, the Ang2(-/- mice demonstrated a significantly attenuated response. The Ang-2(-/- phenotype was rescued by systemic administration (paracrine of an adenovirus encoding Ang-2. Furthermore, cytokine-induced intracellular calcium influx was impaired in Ang-2(-/- endothelioma cells, consistent with reduced phospholipase activation in vivo. Additionally, recombinant human Ang-2 (rhAng-2 alone was unable to induce vascular leakage. In summary, we report here in a definite genetic setting that Ang-2 is critical for multiple vascular permeability-inducing cytokines.

  1. SETI via Leakage from Light Sails in Exoplanetary Systems

    CERN Document Server

    Guillochon, James

    2015-01-01

    The primary challenge of rocket propulsion is the burden of needing to accelerate the spacecraft's own fuel, resulting in only a logarithmic gain in maximum speed as propellant is added to the spacecraft. Light sails offer an attractive alternative in which fuel is not carried by the spacecraft, with acceleration being provided by an external source of light. By artificially illuminating the spacecraft with beamed radiation, speeds are only limited by the area of the sail, heat resistance of its material, and power use of the accelerating apparatus. In this paper, we show that leakage from a light sail propulsion apparatus in operation around a solar system analogue would be detectable. To demonstrate this, we model the launch and arrival of a microwave beam-driven light sail constructed for transit between planets in orbit around a single star, and find an optimal beam frequency on the order of tens of GHz. Leakage from these beams yields transients with flux densities of 0.1 Jy and durations of seconds at 1...

  2. PURY: a database of geometric restraints of hetero compounds for refinement in complexes with macromolecular structures.

    Science.gov (United States)

    Andrejasic, Miha; Praaenikar, Jure; Turk, Dusan

    2008-11-01

    The number and variety of macromolecular structures in complex with ;hetero' ligands is growing. The need for rapid delivery of correct geometric parameters for their refinement, which is often crucial for understanding the biological relevance of the structure, is growing correspondingly. The current standard for describing protein structures is the Engh-Huber parameter set. It is an expert data set resulting from selection and analysis of the crystal structures gathered in the Cambridge Structural Database (CSD). Clearly, such a manual approach cannot be applied to the vast and ever-growing number of chemical compounds. Therefore, a database, named PURY, of geometric parameters of chemical compounds has been developed, together with a server that accesses it. PURY is a compilation of the whole CSD. It contains lists of atom classes and bonds connecting them, as well as angle, chirality, planarity and conformation parameters. The current compilation is based on CSD 5.28 and contains 1978 atom classes and 32,702 bonding, 237,068 angle, 201,860 dihedral and 64,193 improper geometric restraints. Analysis has confirmed that the restraints from the PURY database are suitable for use in macromolecular crystal structure refinement and should be of value to the crystallographic community. The database can be accessed through the web server http://pury.ijs.si/, which creates topology and parameter files from deposited coordinates in suitable forms for the refinement programs MAIN, CNS and REFMAC. In the near future, the server will move to the CSD website http://pury.ccdc.cam.ac.uk/.

  3. A 3D image filter for parameter-free segmentation of macromolecular structures from electron tomograms.

    Directory of Open Access Journals (Sweden)

    Rubbiya A Ali

    Full Text Available 3D image reconstruction of large cellular volumes by electron tomography (ET at high (≤ 5 nm resolution can now routinely resolve organellar and compartmental membrane structures, protein coats, cytoskeletal filaments, and macromolecules. However, current image analysis methods for identifying in situ macromolecular structures within the crowded 3D ultrastructural landscape of a cell remain labor-intensive, time-consuming, and prone to user-bias and/or error. This paper demonstrates the development and application of a parameter-free, 3D implementation of the bilateral edge-detection (BLE algorithm for the rapid and accurate segmentation of cellular tomograms. The performance of the 3D BLE filter has been tested on a range of synthetic and real biological data sets and validated against current leading filters-the pseudo 3D recursive and Canny filters. The performance of the 3D BLE filter was found to be comparable to or better than that of both the 3D recursive and Canny filters while offering the significant advantage that it requires no parameter input or optimisation. Edge widths as little as 2 pixels are reproducibly detected with signal intensity and grey scale values as low as 0.72% above the mean of the background noise. The 3D BLE thus provides an efficient method for the automated segmentation of complex cellular structures across multiple scales for further downstream processing, such as cellular annotation and sub-tomogram averaging, and provides a valuable tool for the accurate and high-throughput identification and annotation of 3D structural complexity at the subcellular level, as well as for mapping the spatial and temporal rearrangement of macromolecular assemblies in situ within cellular tomograms.

  4. A 3D image filter for parameter-free segmentation of macromolecular structures from electron tomograms.

    Science.gov (United States)

    Ali, Rubbiya A; Landsberg, Michael J; Knauth, Emily; Morgan, Garry P; Marsh, Brad J; Hankamer, Ben

    2012-01-01

    3D image reconstruction of large cellular volumes by electron tomography (ET) at high (≤ 5 nm) resolution can now routinely resolve organellar and compartmental membrane structures, protein coats, cytoskeletal filaments, and macromolecules. However, current image analysis methods for identifying in situ macromolecular structures within the crowded 3D ultrastructural landscape of a cell remain labor-intensive, time-consuming, and prone to user-bias and/or error. This paper demonstrates the development and application of a parameter-free, 3D implementation of the bilateral edge-detection (BLE) algorithm for the rapid and accurate segmentation of cellular tomograms. The performance of the 3D BLE filter has been tested on a range of synthetic and real biological data sets and validated against current leading filters-the pseudo 3D recursive and Canny filters. The performance of the 3D BLE filter was found to be comparable to or better than that of both the 3D recursive and Canny filters while offering the significant advantage that it requires no parameter input or optimisation. Edge widths as little as 2 pixels are reproducibly detected with signal intensity and grey scale values as low as 0.72% above the mean of the background noise. The 3D BLE thus provides an efficient method for the automated segmentation of complex cellular structures across multiple scales for further downstream processing, such as cellular annotation and sub-tomogram averaging, and provides a valuable tool for the accurate and high-throughput identification and annotation of 3D structural complexity at the subcellular level, as well as for mapping the spatial and temporal rearrangement of macromolecular assemblies in situ within cellular tomograms.

  5. Wind-induced internal pressure response for structure with single windward opening and background leakage

    Institute of Scientific and Technical Information of China (English)

    Shi-ce YU; Wen-juan LOU; Bing-nan SUN

    2008-01-01

    Theoretical analysis and wind tunnel tests were carried out to study wind-induced internal pressure response for the structure with single windward opening and background leakage. Its governing differential equation was derived by the Bernoulli equation in an unsteady-isentropic form. Numerical examples were provided to study the additive damping caused by background leakage in laminar and turbulent flow, and the influence of background leakage on fluctuating internal pressure response was quantized. A series of models for low-rise building with various opening ratios and background leakage were designed and wind tunnel tests were conducted. It is shown that the fluctuating internal pressure reduces when the background leakage are considered and that the effect of background leakage can be predicted accurately by the governing differential equation deduced in this paper.

  6. An Enhanced Leakage-Based Precoding Scheme for Multi-User Multi-Layer MIMO Systems

    OpenAIRE

    Yang, Chunliang

    2014-01-01

    In this paper, we propose an enhanced leakage-based precoding scheme, i.e., layer signal to leakage plus noise ratio (layer SLNR) scheme, for multi-user multi-layer MIMO systems. Specifically, the layer SLNR scheme incorporates the MIMO receiver structure into the precoder design procedure, which makes the formulation of signal power and interference / leakage power more accurate. Besides, the layer SLNR scheme not only takes into account the inter-layer interference from different users, but...

  7. Complete analytical calculation of static leakage parameters. Application to planar HF transformer optimization

    OpenAIRE

    Margueron, Xavier; Keradec, Jean-Pierre; Besri, Abdelhadi

    2007-01-01

    International audience; The pre-determination of transformer leakage inductances is essential for component designers. Except for special winding disposal, usual analytical methods of evaluation are useless and fem simulation evaluation, even more widely applicable, requires a time unsuitable with any optimization process. Work presented here is based on an analytical method we published recently about leakage inductances calculation. In the present paper, an explicit expression of leakage in...

  8. Estimation of leakage power and delay in CMOS circuits using parametric variation

    Directory of Open Access Journals (Sweden)

    Preeti Verma

    2016-09-01

    Full Text Available With the advent of deep-submicron technologies, leakage power dissipation is a major concern for scaling down portable devices that have burst-mode type integrated circuits. In this paper leakage reduction technique HTLCT (High Threshold Leakage Control Transistor is discussed. Using high threshold transistors at the place of low threshold leakage control transistors, result in more leakage power reduction as compared to LCT (leakage control transistor technique but at the scarifies of area and delay. Further, analysis of effect of parametric variation on leakage current and propagation delay in CMOS circuits is performed. It is found that the leakage power dissipation increases with increasing temperature, supply voltage and aspect ratio. However, opposite pattern is noticed for the propagation delay. Leakage power dissipation for LCT NAND gate increases up to 14.32%, 6.43% and 36.21% and delay decreases by 22.5%, 42% and 9% for variation of temperature, supply voltage and aspect ratio. Maximum peak of equivalent output noise is obtained as 127.531 nV/Sqrt(Hz at 400 mHz.

  9. A Novel Technique for Glitch and Leakage Power Reduction in CMOS VLSI Circuits

    Directory of Open Access Journals (Sweden)

    Pushpa Saini

    2012-10-01

    Full Text Available Leakage power has become a serious concern in nanometer CMOS technologies. Dynamic and leakage power both are the main contributors to the total power consumption. In the past, the dynamic power has dominated the total power dissipation of CMOS devices. However, with the continuous trend of technology scaling, leakage power is becoming a main contributor to power consumption. In this paper, a technique has been proposed which will reduce simultaneously both glitch and leakage power. The results are simulated in Microwind3.1 in 90nm and 250 nm technology at room temperature.

  10. Effects of leakage inductances on magnetically-coupled impedance-source networks

    DEFF Research Database (Denmark)

    Siwakoti, Yam P.; Loh, Poh Chiang; Blaabjerg, Frede;

    2014-01-01

    Coupled inductors have lately been used with impedance-source networks for keeping their shoot-through times short, while providing higher voltage boosts. The parameter that is critical to the operation of such impedance network based converter with coupled inductors is the leakage inductances. H....... However, the role of leakage inductances and its effect on the converter performance is often overlooked. This paper analyzes the effects of leakage inductances and demonstrates experimentally how the presence of leakage inductances degrades the performance of the converter....

  11. Method of detecting leakage from geologic formations used to sequester CO.sub.2

    Science.gov (United States)

    White, Curt; Wells, Arthur; Diehl, J. Rodney; Strazisar, Brian

    2010-04-27

    The invention provides methods for the measurement of carbon dioxide leakage from sequestration reservoirs. Tracer moieties are injected along with carbon dioxide into geological formations. Leakage is monitored by gas chromatographic analyses of absorbents. The invention also provides a process for the early leak detection of possible carbon dioxide leakage from sequestration reservoirs by measuring methane (CH.sub.4), ethane (C.sub.2H.sub.6), propane (C.sub.3H.sub.8), and/or radon (Rn) leakage rates from the reservoirs. The invention further provides a method for branding sequestered carbon dioxide using perfluorcarbon tracers (PFTs) to show ownership.

  12. Reanastomosis with Stapler in Duodenojejunal Junction Anastomosis Leakage: A Case Report

    Directory of Open Access Journals (Sweden)

    Ahmet Seker

    2013-04-01

    Full Text Available After anastomosis leakages, treatment of patient gets more difficult and mortality rates increase. At lower level gastrointestinal anastomosis leakages, because of always there is an ostomy alternative, digestion problems are seen lesser. But at upper level gastrointestinal system anastomosis leakages, when it is taken account of nutrient condition of patient, requirement of making anastomos increases. So moratlity rates increase. At this article we aimed to present a different technique that we administered on management of a patient who had duodenojejunal junction anastomosis leakage.

  13. On leakage and seepage from geological carbon sequestration sites

    Energy Technology Data Exchange (ETDEWEB)

    Oldenburg, C.M.; Unger, A.J.A.; Hepple, R.P.; Jordan, P.D.

    2002-07-18

    Geologic carbon sequestration is one strategy for reducing the rate of increase of global atmospheric carbon dioxide (CO{sub 2} ) concentrations (IEA, 1997; Reichle, 2000). As used here, the term geologic carbon sequestration refers to the direct injection of supercritical CO{sub 2} deep into subsurface target formations. These target formations will typically be either depleted oil and gas reservoirs, or brine-filled permeable formations referred to here as brine formations. Injected CO{sub 2} will tend to be trapped by one or more of the following mechanisms: (1) permeability trapping, for example when buoyant supercritical CO{sub 2} rises until trapped by a confining caprock; (2) solubility trapping, for example when CO{sub 2} dissolves into the aqueous phase in water-saturated formations, or (3) mineralogic trapping, such as occurs when CO{sub 2} reacts to produce stable carbonate minerals. When CO{sub 2} is trapped in the subsurface by any of these mechanisms, it is effectively sequestered away from the atmosphere where it would otherwise act as a greenhouse gas. The purpose of this report is to summarize our work aimed at quantifying potential CO{sub 2} seepage due to leakage from geologic carbon sequestration sites. The approach we take is to present first the relevant properties of CO{sub 2} over the range of conditions from the deep subsurface to the vadose zone (Section 2), and then discuss conceptual models for how leakage might occur (Section 3). The discussion includes consideration of gas reservoir and natural gas storage analogs, along with some simple estimates of seepage based on assumed leakage rates. The conceptual model discussion provides the background for the modeling approach wherein we focus on simulating transport in the vadose zone, the last potential barrier to CO{sub 2} seepage (Section 4). Because of the potentially wide range of possible properties of actual future geologic sequestration sites, we carry out sensitivity analyses by

  14. Modeling of leakage currents in high-k dielectrics

    Energy Technology Data Exchange (ETDEWEB)

    Jegert, Gunther Christian

    2012-03-15

    Leakage currents are one of the major bottlenecks impeding the downscaling efforts of the semiconductor industry. Two core devices of integrated circuits, the transistor and, especially, the DRAM storage capacitor, suffer from the increasing loss currents. In this perspective a fundamental understanding of the physical origin of these leakage currents is highly desirable. However, the complexity of the involved transport phenomena so far has prevented the development of microscopic models. Instead, the analysis of transport through the ultra-thin layers of high-permittivity (high-k) dielectrics, which are employed as insulating layers, was carried out at an empirical level using simple compact models. Unfortunately, these offer only limited insight into the physics involved on the microscale. In this context the present work was initialized in order to establish a framework of microscopic physical models that allow a fundamental description of the transport processes relevant in high-k thin films. A simulation tool that makes use of kinetic Monte Carlo techniques was developed for this purpose embedding the above models in an environment that allows qualitative and quantitative analyses of the electronic transport in such films. Existing continuum approaches, which tend to conceal the important physics behind phenomenological fitting parameters, were replaced by three-dimensional transport simulations at the level of single charge carriers. Spatially localized phenomena, such as percolation of charge carriers across pointlike defects, being subject to structural relaxation processes, or electrode roughness effects, could be investigated in this simulation scheme. Stepwise a self-consistent, closed transport model for the TiN/ZrO{sub 2} material system, which is of outmost importance for the semiconductor industry, was developed. Based on this model viable strategies for the optimization of TiN/ZrO{sub 2}/TiN capacitor structures were suggested and problem areas

  15. On Leakage from Geologic Storage Reservoirs of CO2

    Energy Technology Data Exchange (ETDEWEB)

    Pruess, Karsten

    2006-02-14

    Large amounts of CO2 would need to be injected underground to achieve a significant reduction of atmospheric emissions. The large areal extent expected for CO2 plumes makes it likely that caprock imperfections will be encountered, such as fault zones or fractures, which may allow some CO2 to escape from the primary storage reservoir. Leakage of CO2 could also occur along wellbores. Concerns with escape of CO2 from a primary geologic storage reservoir include (1) acidification of groundwater resources, (2) asphyxiation hazard when leaking CO2 is discharged at the land surface, (3) increase in atmospheric concentrations of CO2, and (4) damage from a high-energy, eruptive discharge (if such discharge is physically possible). In order to gain public acceptance for geologic storage as a viable technology for reducing atmospheric emissions of CO2, it is necessary to address these issues and demonstrate that CO2 can be injected and stored safely in geologic formations.

  16. Dynamic modeling of a solar hydrogen system under leakage conditions

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, J.J. [Graduate Institute of Greenergy Technology, National University of Tainan, Tainan (China); Chang, W.R. [Department of Landscape Architecture, Chung-Hua University, Hsinchu 300 (China); Su, A. [Department of Mechanical Engineering and Fuel Cell Center, Yuan Ze University, Taoyuan (China)

    2008-07-15

    Dynamic behaviors of an integrated solar hydrogen system have been modeled mathematically, which is based on a combination of fundamental theories of thermodynamics, mass transfer, fluid dynamics, and empirical electrochemical relationships. The model considers solar hydrogen system to be composed of three subsystems, i.e., solar cells, an electrolyzer, and a hydrogen tank. An additional pressure switch model is presented to visualize the hydrogen storage dynamics under a leakage condition. Validation of the solar hydrogen model system is evaluated according to the measured data from the manufacturer's data. Then, the overall was simulated by using solar irradiation as the primary energy input and hydrogen as energy storage for one-day operation. Finally, electrical characteristics and efficiencies of each subsystem as well as the entire system are presented and discussed. (author)

  17. Structural and leakage integrity of tubes affected by circumferential cracking

    Energy Technology Data Exchange (ETDEWEB)

    Hernalsteen, P. [TRACTEBEL, Brussels (Belgium)

    1997-02-01

    In this paper the author deals with the notion that circumferential cracks are generally considered unacceptable. He argues for the need to differentiate two facets of such cracks: the issue of the size and growth rate of a crack; and the issue of the structural strength and leakage potential of the tube in the presence of the crack. In this paper the author tries to show that the second point is not a major concern for such cracks. The paper presents data on the structural strength or burst pressure characteristics of steam generator tubes derived from models and data bases of experimental work. He also presents a leak rate model, and compares the performance of circumferential and axial cracks as far as burst strength and leak rate. The final conclusion is that subject to improvement in NDE capabilities (sizing, detection, growth), that Steam Generator Defect Specific Management can be used to allow circumferentially degraded tubes to remain in service.

  18. Comprehensive failure analysis of leakage faults in bipolar transistors

    Science.gov (United States)

    Domengès, B.; Murray, H.; Schwindenhammer, P.; Imbert, G.

    2004-02-01

    The origin of a leakage current in several failed NPN bipolar transistors has been identified by complementary advanced failure analysis techniques. After precise localization of the failing area by photon emission microscopy and optical beam induced resistance change investigations, a focus ion beam technique was used to prepare thin lamellae adequate for transmission electron microscopy (TEM) study. Characterization of the related microstructure was performed by TEM and energy-dispersive spectrometry nanobeam analyses. It was identified as Ti-W containing trickle-like residue located at the surface of the spacers. Current-voltage measurements could be related to such structure defects and the involved conduction mechanism was identified as the Poole-Frenkel effect.

  19. Highly sensitive optical sensor system for blood leakage detection

    Science.gov (United States)

    Ueda, Masahiro; Ishikawa, Kazuhiko; Jie, Chen; Sanae, Mizuno; Touma, Yasunori

    A highly sensitive method for the detection of blood leakage has been developed, and a practical sensor system for blood concentration measurement has been constructed. The present method is based on the attenuation of laser light by blood cells. The effects of the fluctuations of the incident laser light power are eliminated by normalizing the attenuated light intensity by the incident light intensity. A part of the incident laser light is reflected by a beam splitter mounted at the entrance of the test cell, of which the power is measured to provide base data for normalization. The optical path is extended to enhance sensitivity by using a pair of side mirrors. This multi-reflection method is very effective to increase sensitivity; the maximum sensitivity obtained for blood concentration is about 4 X 10 -6 by volume, which is significantly higher than that of the conventional sensors.

  20. Moisture Risk in Unvented Attics Due to Air Leakage Paths

    Energy Technology Data Exchange (ETDEWEB)

    Prahl, D. [IBACOS, Inc., Pittsburgh, PA (United States); Shaffer, M. [IBACOS, Inc., Pittsburgh, PA (United States)

    2014-11-01

    IBACOS completed an initial analysis of moisture damage potential in an unvented attic insulated with closed-cell spray polyurethane foam. To complete this analysis, the research team collected field data, used computational fluid dynamics to quantify the airflow rates through individual airflow (crack) paths, simulated hourly flow rates through the leakage paths with CONTAM software, correlated the CONTAM flow rates with indoor humidity ratios from Building Energy Optimization software, and used Wärme und Feuchte instationär Pro two-dimensional modeling to determine the moisture content of the building materials surrounding the cracks. Given the number of simplifying assumptions and numerical models associated with this analysis, the results indicate that localized damage due to high moisture content of the roof sheathing is possible under very low airflow rates. Reducing the number of assumptions and approximations through field studies and laboratory experiments would be valuable to understand the real-world moisture damage potential in unvented attics.

  1. Moisture Risk in Unvented Attics Due to Air Leakage Paths

    Energy Technology Data Exchange (ETDEWEB)

    Prahl, D.; Shaffer, M.

    2014-11-01

    IBACOS completed an initial analysis of moisture damage potential in an unvented attic insulated with closed-cell spray polyurethane foam. To complete this analysis, the research team collected field data, used computational fluid dynamics to quantify the airflow rates through individual airflow (crack) paths, simulated hourly flow rates through the leakage paths with CONTAM software, correlated the CONTAM flow rates with indoor humidity ratios from Building Energy Optimization software, and used Warme und Feuchte instationar Pro two-dimensional modeling to determine the moisture content of the building materials surrounding the cracks. Given the number of simplifying assumptions and numerical models associated with this analysis, the results indicate that localized damage due to high moisture content of the roof sheathing is possible under very low airflow rates. Reducing the number of assumptions and approximations through field studies and laboratory experiments would be valuable to understand the real-world moisture damage potential in unvented attics.

  2. Evaluation of Surface Cracks Using Magnetic Flux Leakage Testing

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The magnetic field distribution characteristics of surface cracks with various widths are discussed based on finite element (FEM) results. The crack depth was 0.20 mm, the width range was from 0.02 to 1.00 mm. The results showed that crack width and lift-off (the distance between surface and sensor) will influence signals. Discussed in this paper is the influence of various lift-off parameters on the peak to peak values of the normal component in magnetic flux leakage testing. The effects can be applied to evaluate surface breaking cracks of different widths and depths.An idea is presented to smooth narrow, sharp crack tips using alternating current (AC) field magnetization.

  3. Quench tank in-leakage diagnosis at St. Lucie

    Energy Technology Data Exchange (ETDEWEB)

    Price, J.E.; Au-Yang, M.K.; Beckner, D.A.; Vickery, A.N.

    1996-12-01

    In February 1995, leakage into the quench tank of the St. Lucie Nuclear Station Unit 1 was becoming an operational concern. This internal leak resulted in measurable increases in both the temperature and level of the quench tank water, and was so severe that, if the trend continued, plant shut down would be necessary. Preliminary diagnosis based on in-plant instrumentation indicated that any one of 11 valves might be leaking into the quench tank. This paper describes the joint effort by two teams of engineers--one from Florida Power & Light, the other from Framatome Technologies--to identify the sources of the leak, using the latest technology developed for valve diagnosis.

  4. Pressured liquid chlorine leakage accident simulation in highway tunnel

    Directory of Open Access Journals (Sweden)

    LI Jianfeng, LIU Mao, WANG Wei

    2010-03-01

    Full Text Available With the national economic development, China's transportation infrastructure has also made great progress, particularly in the highway. How to reduce the accident consequence that occurred in the highway tunnel has been the tropical topic in China. The liquid Chlorine accidental leakage in highway tunnel was exemplified for the poisonous gas dispersion consequence analysis using computational fluid dynamics. First, the GAMBIT code was used to create geometrical models and generate meshes. Second, by using the FLUENT code, the Chlorine gas dispersion in the highway tunnel was simulated and the scenarios with different leak sources were discussed. Case study shows that the FLUENT code was useful on the simulation of gas dispersion in highway tunnel that serves the prerequisite for the further research.

  5. A nationwide study on anastomotic leakage after colonic cancer surgery

    DEFF Research Database (Denmark)

    Krarup, Peter-Martin; Jorgensen, L N; Andreasen, A H

    2012-01-01

    Aim: Anastomotic leakage (AL) is a major challenge in colorectal cancer surgery due to increased morbidity and mortality. Possible risk factors should be investigated differentially, distinguishing between rectal and colonic surgery in large-scale studies to avoid selection bias and confounding....... Method: The incidence and risk factors associated with AL were analysed in an unselected nation-wide prospective cohort of patient subjected to curative colonic cancer surgery with primary anastomosis and entered into The Danish Colorectal Cancer Group database between May 2001 and December 2008. Results......: AL occurred in 593 (6.4%) of 9333 patients. Laparoscopic surgery (odds ratio [OR], 1.34; 95% confidence interval [CI], 1.05-1.70; P = 0.03); left hemicolectomy (OR, 2.02; 95% CI, 1.50-2.72) or sigmoid colectomy (OR, 1.69; 95% CI, 1.32-2.17; P = 0.01); intraoperative blood loss (OR, 1.04; 95% CI, 1...

  6. [A mobile sensor for remote detection of natural gas leakage].

    Science.gov (United States)

    Zhang, Shuai; Liu, Wen-qing; Zhang, Yu-jun; Kan, Rui-feng; Ruan, Jun; Wang, Li-ming; Yu, Dian-qiang; Dong, Jin-ting; Han, Xiao-lei; Cui, Yi-ben; Liu, Jian-guo

    2012-02-01

    The detection of natural gas pipeline leak becomes a significant issue for body security, environmental protection and security of state property. However, the leak detection is difficult, because of the pipeline's covering many areas, operating conditions and complicated environment. A mobile sensor for remote detection of natural gas leakage based on scanning wavelength differential absorption spectroscopy (SWDAS) is introduced. The improved soft threshold wavelet denoising was proposed by analyzing the characteristics of reflection spectrum. And the results showed that the signal to noise ratio (SNR) was increased three times. When light intensity is 530 nA, the minimum remote sensitivity will be 80 ppm x m. A widely used SWDAS can make quantitative remote sensing of natural gas leak and locate the leak source precisely in a faster, safer and more intelligent way.

  7. SETI VIA LEAKAGE FROM LIGHT SAILS IN EXOPLANETARY SYSTEMS

    Energy Technology Data Exchange (ETDEWEB)

    Guillochon, James; Loeb, Abraham, E-mail: jguillochon@cfa.harvard.edu, E-mail: aloeb@cfa.harvard.edu [Harvard-Smithsonian Center for Astrophysics, The Institute for Theory and Computation, 60 Garden Street, Cambridge, MA 02138 (United States)

    2015-10-01

    The primary challenge of rocket propulsion is the burden of needing to accelerate the spacecraft’s own fuel, resulting in only a logarithmic gain in maximum speed as propellant is added to the spacecraft. Light sails offer an attractive alternative in which fuel is not carried by the spacecraft, with acceleration being provided by an external source of light. By artificially illuminating the spacecraft with beamed radiation, speeds are only limited by the area of the sail, heat resistance of its material, and power use of the accelerating apparatus. In this paper, we show that leakage from a light sail propulsion apparatus in operation around a solar system analogue would be detectable. To demonstrate this, we model the launch and arrival of a microwave beam-driven light sail constructed for transit between planets in orbit around a single star, and find an optimal beam frequency on the order of tens of GHz. Leakage from these beams yields transients with flux densities of Jy and durations of tens of seconds at 100 pc. Because most travel within a planetary system would be conducted between the habitable worlds within that system, multiply transiting exoplanetary systems offer the greatest chance of detection, especially when the planets are in projected conjunction as viewed from Earth. If interplanetary travel via beam-driven light sails is commonly employed in our galaxy, this activity could be revealed by radio follow-up of nearby transiting exoplanetary systems. The expected signal properties define a new strategy in the search for extraterrestrial intelligence (SETI)

  8. Compensation for booster leakage field in the Duke storage ring

    Science.gov (United States)

    Li, Wei; Hao, Hao; Mikhailov, Stepan F.; Popov, Victor; Li, Wei-Min; Wu, Ying. K.

    2017-01-01

    The High Intensity Gamma-ray Source (HIGS) at Duke University is an accelerator-driven Compton gamma-ray source, providing high flux gamma-ray beam from 1 MeV to 100 MeV for photo-nuclear physics research. The HIGS facility operates three accelerators, a linac pre-injector (0.16 GeV), a booster injector (0.16—1.2 GeV), and an electron storage ring (0.24—1.2 GeV). Because of the proximity of the booster injector to the storage ring, the magnetic field of the booster dipoles close to the ring can significantly alter the closed orbit in the storage ring being operated in the low energy region. This type of orbit distortion can be a problem for certain precision experiments which demand a high degree of energy consistency of the gamma-ray beam. This energy consistency can be achieved by maintaining consistent aiming of the gamma-ray beam, and therefore a steady electron beam orbit and angle at the Compton collision point. To overcome the booster leakage field problem, we have developed an orbit compensation scheme. This scheme is developed using two fast orbit correctors and implemented as a feedforward which is operated transparently together with the slow orbit feedback system. In this paper, we will describe the development of this leakage field compensation scheme, and report the measurement results, which demonstrate the effectiveness of the scheme. Supported by National Natural Science Foundation of China (11175180, 11475167) and US DOE (DE-FG02-97ER41033)

  9. SETI via Leakage from Light Sails in Exoplanetary Systems

    Science.gov (United States)

    Guillochon, James; Loeb, Abraham

    2015-10-01

    The primary challenge of rocket propulsion is the burden of needing to accelerate the spacecraft’s own fuel, resulting in only a logarithmic gain in maximum speed as propellant is added to the spacecraft. Light sails offer an attractive alternative in which fuel is not carried by the spacecraft, with acceleration being provided by an external source of light. By artificially illuminating the spacecraft with beamed radiation, speeds are only limited by the area of the sail, heat resistance of its material, and power use of the accelerating apparatus. In this paper, we show that leakage from a light sail propulsion apparatus in operation around a solar system analogue would be detectable. To demonstrate this, we model the launch and arrival of a microwave beam-driven light sail constructed for transit between planets in orbit around a single star, and find an optimal beam frequency on the order of tens of GHz. Leakage from these beams yields transients with flux densities of Jy and durations of tens of seconds at 100 pc. Because most travel within a planetary system would be conducted between the habitable worlds within that system, multiply transiting exoplanetary systems offer the greatest chance of detection, especially when the planets are in projected conjunction as viewed from Earth. If interplanetary travel via beam-driven light sails is commonly employed in our galaxy, this activity could be revealed by radio follow-up of nearby transiting exoplanetary systems. The expected signal properties define a new strategy in the search for extraterrestrial intelligence (SETI).

  10. Mind the gap - tip leakage vortex in axial turbines

    Science.gov (United States)

    Dreyer, M.; Decaix, J.; Münch-Alligné, C.; Farhat, M.

    2014-03-01

    The tendency of designing large Kaplan turbines with a continuous increase of output power is bringing to the front the cavitation erosion issue. Due to the flow in the gap between the runner and the discharge ring, axial turbine blades may develop the so called tip leakage vortex (TLV) cavitation with negative consequences. Such vortices may interact strongly with the wake of guide vanes leading to their multiple collapses and rebounds. If the vortex trajectory remains close to the blade tip, these collapses may lead to severe erosion. One is still unable today to predict its occurrence and development in axial turbines with acceptable accuracy. Numerical flow simulations as well as the actual scale-up rules from small to large scales are unreliable. The present work addresses this problematic in a simplified case study representing TLV cavitation to better understand its sensitivity to the gap width. A Naca0009 hydrofoil is used as a generic blade in the test section of EPFL cavitation tunnel. A sliding mounting support allowing an adjustable gap between the blade tip and wall was manufactured. The vortex trajectory is visualized with a high speed camera and appropriate lighting. The three dimensional velocity field induced by the TLV is investigated using stereo particle image velocimetry. We have taken into account the vortex wandering in the image processing to obtain accurate measurements of the vortex properties. The measurements were performed in three planes located downstream of the hydrofoil for different values of the flow velocity, the incidence angle and the gap width. The results clearly reveal a strong influence of the gap width on both trajectory and intensity of the tip leakage vortex.

  11. Experimental determination of methane dissolution from simulated subsurface oil leakages

    Science.gov (United States)

    Sauthoff, W.; Peltzer, E. T.; Walz, P. M.; Brewer, P. G.

    2013-12-01

    Subsurface oil leakages and increased offshore drilling efforts have raised concern over the fate of hydrocarbon mixtures of oil and gas in ocean environments. Recent wellhead and pipeline failures in the Gulf of Mexico are extreme examples of this problem. Understanding the mechanism and rate of vertical transport of hydrocarbon chemical species is necessary to predict the environmental impact of subsurface leakages. In a series of controlled experiments, we carried out a deep-sea field experiment in Monterey Canyon to investigate the behavior of a gas-saturated liquid hydrocarbon mass rising from the seafloor. Aboard the R/V Rachel Carson, we used the ROV Ventana to transport a laboratory prepared volume of decane (C10H22) saturated with methane gas (CH4) to mimic a subsurface seafloor discharge. We released the oil and gas mixture into a vertically oriented open bottom glass tube followed by methane loss rate measurements both at discrete depths, and during rapid, continuous vehicle ascent from 800 to 100 m water depth to monitor changes in dissolution and bubble nucleation. Using laser Raman techniques and HD video we quantified the chemical state of the hydrocarbon fluid, including rate of methane gas dissolution. The primary methane Raman peak was readily observable within the decane C-H stretching complex. Variation in the amount of gas dissolved in the oil greatly influences oil plume density and in turn oil plume vertical rise rate. Our results show that the rise rate of the hydrocarbon mass significantly exceeds the rate at which the excess methane was lost by dissolution. This result implies that vertical transport of methane in the saturated hydrocarbon liquid phase can greatly exceed a gas bubble plume ascending the water column from a seafloor source. These results and observations may be applicable to improved understanding of the composition, distribution, and environmental fate of leaked hydrocarbon mixtures and inform remediation efforts.

  12. Numerical studies on the performance of an aerosol respirator with faceseal leakage

    Science.gov (United States)

    Zaripov, S. K.; Mukhametzanov, I. T.; Grinshpun, S. A.

    2016-11-01

    We studied the efficiency of a facepiece filtering respirator (FFR) in presence of a measurable faceseal leakage using the previously developed model of a spherical sampler with porous layer. In our earlier study, the model was validated for a specific filter permeability value. In this follow-up study, we investigated the effect of permeability on the overall respirator performance accounting for the faceseal leakage. The Total Inward Leakage (TIL) was calculated as a function of the leakage-to-filter surface ratio and the particle diameter. A good correlation was found between the theoretical and experimental TIL values. The TIL value was shown to increase and the effect of particle size on TIL to decrease as the leakage-to- filter surface ratio grows. The model confirmed that within the most penetrating particle size range (∼50 nm) and at relatively low leakage-to-filter surface ratios, an FFR performs better (TIL is lower) when the filter has a lower permeability which should be anticipated as long as the flow through the filter represents the dominant particle penetration pathway. An increase in leak size causes the TIL to rise; furthermore, under certain leakage-to-filter surface ratios, TIL for ultrafine particles becomes essentially independent on the filter properties due to a greater contribution of the aerosol flow through the faceseal leakage. In contrast to the ultrafine fraction, the larger particles (e.g., 800 nm) entering a typical high- or medium-quality respirator filter are almost fully collected by the filter medium regardless of its permeability; at the same time, the fraction penetrated through the leakage appears to be permeability- dependent: higher permeability generally results in a lower pressure drop through the filter which increases the air flow through the filter at the expense of the leakage flow. The latter reduces the leakage effect thus improving the overall respiratory protection level. The findings of this study provide

  13. In vitro analysis of PDZ-dependent CFTR macromolecular signaling complexes.

    Science.gov (United States)

    Wu, Yanning; Wang, Shuo; Li, Chunying

    2012-08-13

    has been shown to be of functional significance, suggesting that PDZ scaffold proteins may facilitate formation of CFTR macromolecular signaling complexes for specific/selective and efficient signaling in cells(16-18). Multiple biochemical assays have been developed to study CFTR-involving protein interactions, such as co-immunoprecipitation, pull-down assay, pair-wise binding assay, colorimetric pair-wise binding assay, and macromolecular complex assembly assay(16-19,28,29). Here we focus on the detailed procedures of assembling a PDZ motif-dependent CFTR-containing macromolecular complex in vitro, which is used extensively by our laboratory to study protein-protein or domain-domain interactions involving CFTR(16-19,28,29).

  14. Macromolecular composition of terrestrial and marine organic matter in sediments across the East Siberian Arctic Shelf

    Science.gov (United States)

    Sparkes, Robert B.; Doğrul Selver, Ayça; Gustafsson, Örjan; Semiletov, Igor P.; Haghipour, Negar; Wacker, Lukas; Eglinton, Timothy I.; Talbot, Helen M.; van Dongen, Bart E.

    2016-10-01

    Mobilisation of terrestrial organic carbon (terrOC) from permafrost environments in eastern Siberia has the potential to deliver significant amounts of carbon to the Arctic Ocean, via both fluvial and coastal erosion. Eroded terrOC can be degraded during offshore transport or deposited across the wide East Siberian Arctic Shelf (ESAS). Most studies of terrOC on the ESAS have concentrated on solvent-extractable organic matter, but this represents only a small proportion of the total terrOC load. In this study we have used pyrolysis-gas chromatography-mass spectrometry (py-GCMS) to study all major groups of macromolecular components of the terrOC; this is the first time that this technique has been applied to the ESAS. This has shown that there is a strong offshore trend from terrestrial phenols, aromatics and cyclopentenones to marine pyridines. There is good agreement between proportion phenols measured using py-GCMS and independent quantification of lignin phenol concentrations (r2 = 0.67, p < 0.01, n = 24). Furfurals, thought to represent carbohydrates, show no offshore trend and are likely found in both marine and terrestrial organic matter. We have also collected new radiocarbon data for bulk OC (14COC) which, when coupled with previous measurements, allows us to produce the most comprehensive 14COC map of the ESAS to date. Combining the 14COC and py-GCMS data suggests that the aromatics group of compounds is likely sourced from old, aged terrOC, in contrast to the phenols group, which is likely sourced from modern woody material. We propose that an index of the relative proportions of phenols and pyridines can be used as a novel terrestrial vs. marine proxy measurement for macromolecular organic matter. Principal component analysis found that various terrestrial vs. marine proxies show different patterns across the ESAS, and it shows that multiple river-ocean transects of surface sediments transition from river-dominated to coastal-erosion-dominated to marine

  15. Solid-state NMR in macromolecular systems: insights on how molecular entities move.

    Science.gov (United States)

    Hansen, Michael Ryan; Graf, Robert; Spiess, Hans Wolfgang

    2013-09-17

    The function of synthetic and natural macromolecularsystems critically depends on the packing and dynamics of the individual components of a given system. Not only can solid-state NMR provide structural information with atomic resolution, but it can also provide a way to characterize the amplitude and time scales of motions over broad ranges of length and time. These movements include molecular dynamics, rotational and translational motions of the building blocks, and also the motion of the functional species themselves, such as protons or ions. This Account examines solid-state NMR methods for correlating dynamics and function in a variety of chemical systems. In the early days, scientists thought that the rotationalmotions reflected the geometry of the moving entities. They described these phenomena as jumps about well-defined axes, such as phenyl flips, even in amorphous polymers. Later, they realized that conformational transitions in macromolecules happen in a much more complex way. Because the individual entities do not rotate around well-defined axes, they require much less space. Only recently researchers have appreciated the relative importance of large angle fluctuations of polymers over rotational jumps. Researchers have long considered that cooperative motions might be at work, yet only recently they have clearly detected these motions by NMR in macromolecular and supramolecular systems. In correlations of dynamics and function, local motions do not always provide the mechanism of long-range transport. This idea holds true in ion conduction but also applies to chain transport in polymer melts and semicrystalline polymers. Similar chain motions and ion transport likewise occur in functional biopolymers, systems where solid-state NMR studies are also performed. In polymer science, researchers have appreciated the unique information on molecular dynamics available from advanced solid-state NMR at times, where their colleagues in the biomacromolecular

  16. Distribution and enzymatic activity of heterotrophic bacteria decomposing selected macromolecular compounds in a Baltic Sea sandy beach

    Science.gov (United States)

    Podgórska, B.; Mudryk, Z. J.

    2003-03-01

    The potential capability to decompose macromolecular compounds, and the level of extracellular enzyme activities were determined in heterotrophic bacteria isolated from a sandy beach in Sopot on the Southern Baltic Sea coast. Individual isolates were capable of hydrolysing a wide spectrum of organic macromolecular compounds. Lipids, gelatine, and DNA were hydrolyzed most efficiently. Only a very small percentage of strains were able to decompose cellulose, and no pectinolytic bacteria were found. Except for starch-hydrolysis, no significant differences in the intensity of organic compound decomposition were recorded between horizontal and vertical profiles of the studied beach. Of all the studied extracellular enzymes, alkaline phosphatase, esterase lipase, and leucine acrylaminidase were most active; in contrast, the activity α-fucosidase, α-galactosidase and β-glucouronidase was the weakest. The level of extracellular enzyme activity was similar in both sand layers.

  17. Chemiluminescence-imaging detection of DNA on a solid-phase membrane by using a peroxidase-labeled macromolecular probe.

    Science.gov (United States)

    Azam, Md Golam; Yamasuji, Mutsumi; Krawczyk, Tomasz; Shibata, Takayuki; Kabashima, Tsutomu; Kai, Masaaki

    2015-07-01

    We have developed a novel method for sensitive chemiluminescence (CL)-imaging detection of DNA by using a macromolecular probe synthesized by attaching multiple molecules of horseradish peroxidase (HRP) and biotin in dextran backbone. The probe formed a macromolecular assembly by binding to streptavidin which specifically recognized biotinylated complementary DNA, which was hybridized to a target DNA on a solid-phase membrane. This methodology was applied to CL-imaging detection of a synthetic telomere DNA (TTAGGG)10 and human telomere DNA by using the CL probe comprising of dextranT2000 (MW=ca. 2000kDa) bonded to approximately 42 molecules of HRP and 210 molecules of biotin. The human telomere DNA in a small number of buccal mucous cells (ca. 70 cell numbers) of cheek tissue was quantitatively determined by the proposed CL detection method that afforded approximately 10 times higher sensitivity than that of the conventional CL method using commercially available HRP-avidin probe.

  18. Leakage Characteristics of Dual-Cannula Fenestrated Tracheostomy Tubes during Positive Pressure Ventilation: A Bench Study

    Directory of Open Access Journals (Sweden)

    Thomas Berlet

    2016-01-01

    Full Text Available This study compared the leakage characteristics of different types of dual-cannula fenestrated tracheostomy tubes during positive pressure ventilation. Fenestrated Portex® Blue Line Ultra®, TRACOE® twist, or Rüsch® Traceofix® tracheostomy tubes equipped with nonfenestrated inner cannulas were tested in a tracheostomy-lung simulator. Transfenestration pressures and transfenestration leakage rates were measured during positive pressure ventilation. The impact of different ventilation modes, airway pressures, temperatures, and simulated static lung compliance settings on leakage characteristics was assessed. We observed substantial differences in transfenestration pressures and transfenestration leakage rates. The leakage rates of the best performing tubes were <3.5% of the delivered minute volume. At body temperature, the leakage rates of these tracheostomy tubes were <1%. The tracheal tube design was the main factor that determined the leakage characteristics. Careful tracheostomy tube selection permits the use of fenestrated tracheostomy tubes in patients receiving positive pressure ventilation immediately after stoma formation and minimises the risk of complications caused by transfenestration gas leakage, for example, subcutaneous emphysema.

  19. Leakage Characteristics of Dual-Cannula Fenestrated Tracheostomy Tubes during Positive Pressure Ventilation: A Bench Study.

    Science.gov (United States)

    Berlet, Thomas; Marchon, Mathias

    2016-01-01

    This study compared the leakage characteristics of different types of dual-cannula fenestrated tracheostomy tubes during positive pressure ventilation. Fenestrated Portex® Blue Line Ultra®, TRACOE® twist, or Rüsch® Traceofix® tracheostomy tubes equipped with nonfenestrated inner cannulas were tested in a tracheostomy-lung simulator. Transfenestration pressures and transfenestration leakage rates were measured during positive pressure ventilation. The impact of different ventilation modes, airway pressures, temperatures, and simulated static lung compliance settings on leakage characteristics was assessed. We observed substantial differences in transfenestration pressures and transfenestration leakage rates. The leakage rates of the best performing tubes were <3.5% of the delivered minute volume. At body temperature, the leakage rates of these tracheostomy tubes were <1%. The tracheal tube design was the main factor that determined the leakage characteristics. Careful tracheostomy tube selection permits the use of fenestrated tracheostomy tubes in patients receiving positive pressure ventilation immediately after stoma formation and minimises the risk of complications caused by transfenestration gas leakage, for example, subcutaneous emphysema.

  20. Leakage Current Elimination of Four-Leg Inverter for Transformerless Three-Phase PV Systems

    DEFF Research Database (Denmark)

    Guo, Xiaoqiang; He, Ran; Jian, Jiamin;

    2016-01-01

    Eliminating the leakage current is one of the most important issues for transformerless three phase photovoltaic (PV) systems. In this paper, the leakage current elimination of a three-phase four-leg PV inverter is investigated. With the common mode loop model established, the generation mechanism...

  1. 77 FR 14445 - Leakage Tests on Packages for Shipment of Radioactive Material

    Science.gov (United States)

    2012-03-09

    ... COMMISSION Leakage Tests on Packages for Shipment of Radioactive Material AGENCY: Nuclear Regulatory... Standard N14.5-1997, ``Radioactive Materials--Leakage Tests on Packages for Shipment'' approved February... receiving radioactive material. II. Further Information Revision 1 of Regulatory Guide 7.4 was issued with...

  2. Blood-brain barrier leakage after status epilepticus in rapamycin-treated rats II: Potential mechanisms

    NARCIS (Netherlands)

    van Vliet, E.A.; Otte, W.M.; Wadman, W.J.; Aronica, E.; Kooij, G.; de Vries, H.E.; Dijkhuizen, R.M.; Gorter, J.A.

    2016-01-01

    OBJECTIVE: Blood-brain barrier (BBB) leakage may play a pro-epileptogenic role after status epilepticus. In the accompanying contrast-enhanced magnetic resonance imaging (CE-MRI) study we showed that the mammalian target of rapamycin (mTOR) inhibitor rapamycin reduced BBB leakage and seizure activit

  3. Blood-brain barrier leakage after status epilepticus in rapamycin-treated rats II : Potential mechanisms

    NARCIS (Netherlands)

    van Vliet, Erwin A; Otte, Wim M; Wadman, Wytse J; Aronica, Eleonora; Kooij, Gijs; de Vries, Helga E; Dijkhuizen, Rick M; Gorter, Jan A

    2016-01-01

    OBJECTIVE: Blood-brain barrier (BBB) leakage may play a pro-epileptogenic role after status epilepticus. In the accompanying contrast-enhanced magnetic resonance imaging (CE-MRI) study we showed that the mammalian target of rapamycin (mTOR) inhibitor rapamycin reduced BBB leakage and seizure activit

  4. The Dutch multicenter experience of the Endo-Sponge treatment for anastomotic leakage after colorectal surgery

    NARCIS (Netherlands)

    P.J. van Koperen; M.I. van Berge Henegouwen; C. Rosman; C.M. Bakker; P. Heres; J.F.M. Slors; W.A. Bemelman

    2009-01-01

    Anastomotic leakage is a feared complication following colorectal surgery and is associated with early and long-term morbidity and mortality. The presacral cavity as the result of leakage can be treated with an endo-sponge (B-Braun Medical). The aim of this study was to assess the effectiveness of e

  5. Can intraluminal devices prevent or reduce colorectal anastomotic leakage : A review

    NARCIS (Netherlands)

    Morks, Annelien N.; Havenga, Klaas; Ploeg, Rutger J.

    2011-01-01

    Colorectal anastomotic leakage is a serious complication of colorectal surgery, leading to high morbidity and mortality rates. In recent decades, many strategies aimed at lowering the incidence of anastomotic leakage have been examined. The focus of this review will be on mechanical aids protecting

  6. Quantification of leakage from large unilamellar lipid vesicles by fluorescence correlation spectroscopy

    DEFF Research Database (Denmark)

    Kristensen, Kasper; Henriksen, Jonas Rosager; Andresen, Thomas Lars

    2014-01-01

    that mastoparan X forms transient transmembrane pores in POPC/POPG (3:1) vesicles, resulting in size-dependent leakage of molecules from the vesicles. We conclude the paper by discussing some of the advantages and limitations of FCS as compared to other existing methods to measure leakage from large unilamellar...

  7. Is aortoiliac calcification linked to colorectal anastomotic leakage? A case-control study

    NARCIS (Netherlands)

    Boersema, G. S. A.; Vakalopoulos, K. A.; Kock, M. C. J. M.; van Ooijen, P. M. A.; Havenga, K.; Kleinrensink, G. J.; Jeekel, J.; Lange, J. F.

    2016-01-01

    Background: Anastomotic leakage in bowel surgery remains a devastating complication. Various risk factors have been uncovered, however, high anastomotic leakage rates are still being reported. This study describes the use of calcification markers of the central abdominal arteries as a prognostic fac

  8. Large eddy simulation of tip-leakage flow in an axial flow fan

    Science.gov (United States)

    Park, Keuntae; Choi, Haecheon; Choi, Seokho; Sa, Yongcheol; Kwon, Oh-Kyoung

    2016-11-01

    An axial flow fan with a shroud generates a complicated tip-leakage flow by the interaction of the axial flow with the fan blades and shroud near the blade tips. In this study, large eddy simulation is performed for tip-leakage flow in a forward-swept axial flow fan inside an outdoor unit of an air-conditioner, operating at the design condition of the Reynolds number of 547,000 based on the radius of blade tip and the tip velocity. A dynamic global model is used for a subgrid-scale model, and an immersed boundary method in a non-inertial reference frame is adopted. The present simulation clearly reveals the generation and evolution of tip-leakage vortex near the blade tip by the leakage flow. At the inception of the leakage vortex near the leading edge of the suction-side of the blade tip, the leakage vortex is composed of unsteady multiple vortices containing high-frequency fluctuations. As the leakage vortex develops downstream along a slant line toward the following blade, large and meandering movements of the leakage vortex are observed. Thus low-frequency broad peaks of velocity and pressure occur near the pressure surface. Supported by the KISTI Supercomputing Center (KSC-2016-C3-0027).

  9. Leakage Current Optimization Techniques During Test Based on Don't Care Bits Assignment

    Institute of Scientific and Technical Information of China (English)

    Wei Wang; Yu Hu; Yin-He Han; Xiao-Wei Li; You-Sheng Zhang

    2007-01-01

    It is a well-known fact that test power consumption may exceed that during functional operation. Leakage power dissipation caused by leakage current in Complementary Metal-Oxide-Semiconductor (CMOS) circuits during test has become a significant part of the total power dissipation. Hence, it is important to reduce leakage power to prolong battery life in portable systems which employ periodic self-test, to increase test reliability and to reduce test cost. This paper analyzes leakage current and presents a kind of leakage current simulator based on the transistor stacking effect.Using it, we propose techniques based on don't care bits (denoted by Xs) in test vectors to optimize leakage current in integrated circuit (IC) test by genetic algorithm. The techniques identify a set of don't care inputs in given test vectors and reassign specified logic values to the X inputs by the genetic algorithm to get minimum leakage vector (MLV).Experimental results indicate that the techniques can effectually optimize leakage current of combinational circuits and sequential circuits during test while maintaining high fault coverage.

  10. Domino logic designs for high-performance and leakage-tolerant applications

    DEFF Research Database (Denmark)

    Moradi, Farshad; Vu Cao, Tuan; Vatajelu, Elena Ioana;

    2013-01-01

    Robustness of high fan-in domino circuits is degraded by technology scaling due to exponential increase in leakage. In this paper, we propose several domino logic circuit techniques to improve the robustness and performance along with leakage power. Lower total power consumption is achieved by ut...

  11. Estimating the environmental and resource costs of leakage in water distribution systems: A shadow price approach.

    Science.gov (United States)

    Molinos-Senante, María; Mocholí-Arce, Manuel; Sala-Garrido, Ramon

    2016-10-15

    Water scarcity is one of the main problems faced by many regions in the XXIst century. In this context, the need to reduce leakages from water distribution systems has gained almost universal acceptance. The concept of sustainable economic level of leakage (SELL) has been proposed to internalize the environmental and resource costs within economic level of leakage calculations. However, because these costs are not set by the market, they have not often been calculated. In this paper, the directional-distance function was used to estimate the shadow price of leakages as a proxy of their environmental and resource costs. This is a pioneering approach to the economic valuation of leakage externalities. An empirical application was carried out for the main Chilean water companies. The estimated results indicated that for 2014, the average shadow price of leakages was approximately 32% of the price of the water delivered. Moreover, as a sensitivity analysis, the shadow prices of the leakages were calculated from the perspective of the water companies' managers and the regulator. The methodology and findings of this study are essential for supporting the decision process of reducing leakage, contributing to the improvement of economic, social and environmental efficiency and sustainability of urban water supplies.

  12. 08B1-1: an automated beamline for macromolecular crystallography experiments at the Canadian Light Source.

    Science.gov (United States)

    Fodje, Michel; Grochulski, Pawel; Janzen, Kathryn; Labiuk, Shaunivan; Gorin, James; Berg, Russ

    2014-05-01

    Beamline 08B1-1 is a recently commissioned bending-magnet beamline at the Canadian Light Source. The beamline is designed for automation and remote access. Together with the undulator-based beamline 08ID-1, they constitute the Canadian Macromolecular Crystallography Facility. This paper describes the design, specifications, hardware and software of beamline 08B1-1. A few scientific results using data obtained at the beamline will be highlighted.

  13. A facile metal-free "grafting-from" route from acrylamide-based substrate toward complex macromolecular combs

    KAUST Repository

    Zhao, Junpeng

    2013-01-01

    High-molecular-weight poly(N,N-dimethylacrylamide-co-acrylamide) was used as a model functional substrate to investigate phosphazene base (t-BuP 4)-promoted metal-free anionic graft polymerization utilizing primary amide moieties as initiating sites. The (co)polymerization of epoxides was proven to be effective, leading to macromolecular combs with side chains being single- or double-graft homopolymer, block copolymer and statistical copolymer. © 2013 The Royal Society of Chemistry.

  14. Conversion efficiency of an energy harvester based on resonant tunneling through quantum dots with heat leakage

    Science.gov (United States)

    Kano, Shinya; Fujii, Minoru

    2017-03-01

    We study the conversion efficiency of an energy harvester based on resonant tunneling through quantum dots with heat leakage. Heat leakage current from a hot electrode to a cold electrode is taken into account in the analysis of the harvester operation. Modeling of electrical output indicates that a maximum heat leakage current is not negligible because it is larger than that of the heat current harvested into electrical power. A reduction of heat leakage is required in this energy harvester in order to obtain efficient heat-to-electrical conversion. Multiple energy levels of a quantum dot can increase the output power of the harvester. Heavily doped colloidal semiconductor quantum dots are a possible candidate for a quantum-dot monolayer in the energy harvester to reduce heat leakage, scaling down device size, and increasing electrical output via multiple discrete energy levels.

  15. Study on leakage flow characteristics of radial inflow turbines at rotor tip clearance

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Tip clearance leakage flow in a radial inflow turbine rotor for microturbines under the stage environment is investigated using a three-dimensional viscous flow simulation. The results indicate that the scraping flow caused by relative motion between casing and rotor tip, and the pressure difference between pressure side and suction side at rotor tip, play important roles in tip clearance leakage flow. The more the rotor tip speed increases and tip clearance height decreases, the more the scraping effect acts. Though the leakage velocity of tip clearance at midsection and exducer regions changes less when the rotor rotational speed is changing, the distance between passage vortex and rotor suction side varies in evidence. Main leakage flow rate of tip clearance takes place at region of exducer tip and some seal configurations will be quite effective for cutting leakage flow if these configurations are arranged over midsection and exducer of the radial inflow rotor.

  16. Study on leakage flow characteristics of radial inflow turbines at rotor tip clearance

    Institute of Scientific and Technical Information of China (English)

    DENG QingHua; NIU JiuFang; FENG ZhenPing

    2008-01-01

    Tip clearance leakage flow in a radial inflow turbine rotor for microturbines under the stage environment is investigated using a three-dimensional viscous flow simulation. The results indicate that the scraping flow caused by relative motion between casing and rotor tip, and the pressure difference between pressure side and suction side at rotor tip, play important roles in tip clearance leakage flow. The more the rotor tip speed increases and tip clearance height decreases, the more the scraping effect acta. Though the leakage velocity of tip clearance at midsection and exducer regions changes less when the rotor rotational speed is changing, the distance between passage vortex and rotor suction side varies in evidence. Main leakage flow rate of tip clearance takes place at region of exducer tip and some seal configurations will be quite effective for cutting leakage flow if these configurations are arranged over midsection and exducer of the radial inflow rotor.

  17. Insulation Resistance and Leakage Currents in Low-Voltage Ceramic Capacitors with Cracks

    Science.gov (United States)

    Teverovsky, Alexander A.

    2016-01-01

    Measurement of insulation resistance (IR) in multilayer ceramic capacitors (MLCCs) is considered a screening technique that ensures the dielectric is defect-free. This work analyzes the effectiveness of this technique for revealing cracks in ceramic capacitors. It is shown that absorption currents prevail over the intrinsic leakage currents during standard IR measurements at room temperature. Absorption currents, and consequently IR, have a weak temperature dependence, increase linearly with voltage (before saturation), and are not sensitive to the presence of mechanical defects. In contrary, intrinsic leakage currents increase super-linearly with voltage and exponentially with temperature (activation energy is in the range from 0.6 eV to 1.1 eV). Leakage currents associated with the presence of cracks have a weaker dependence on temperature and voltage compared to the intrinsic leakage currents. For this reason, intrinsic leakage currents prevail at high temperatures and voltages, thus masking the presence of defects.

  18. Automatic parameter extraction technique for gate leakage current modeling in double gate MOSFET

    Science.gov (United States)

    Darbandy, Ghader; Gneiting, Thomas; Alius, Heidrun; Alvarado, Joaquín; Cerdeira, Antonio; Iñiguez, Benjamin

    2013-11-01

    Direct Tunneling (DT) and Trap Assisted Tunneling (TAT) gate leakage current parameters have been extracted and verified considering automatic parameter extraction approach. The industry standard package IC-CAP is used to extract our leakage current model parameters. The model is coded in Verilog-A and the comparison between the model and measured data allows to obtain the model parameter values and parameters correlations/relations. The model and parameter extraction techniques have been used to study the impact of parameters in the gate leakage current based on the extracted parameter values. It is shown that the gate leakage current depends on the interfacial barrier height more strongly than the barrier height of the dielectric layer. There is almost the same scenario with respect to the carrier effective masses into the interfacial layer and the dielectric layer. The comparison between the simulated results and available measured gate leakage current transistor characteristics of Trigate MOSFETs shows good agreement.

  19. Universal Quantum Computation and Leakage Reduction in the 3-Qubit Decoherence Free Subsystem

    CERN Document Server

    Fong, Bryan H

    2011-01-01

    We describe exchange-only universal quantum computation and leakage reduction in the 3-qubit decoherence free subsystem (DFS). We discuss the angular momentum structure of the DFS, the proper forms for the DFS CNOT and leakage reduction operators in the total angular momentum basis, and new exchange-only pulse sequences for the CNOT and leakage reduction operators. Our new DFS CNOT sequence requires 22 pulses in 13 time steps. The DFS leakage reduction sequence, the first explicit leakage reduction sequence of its kind, requires 30 pulses in 20 time steps. Although the search for sequences was performed numerically using a genetic algorithm, the solutions presented here are exact, with closed-form expressions.

  20. Pipeline leakage recognition based on the projection singular value features and support vector machine

    Energy Technology Data Exchange (ETDEWEB)

    Liang, Wei; Zhang, Laibin; Mingda, Wang; Jinqiu, Hu [College of Mechanical and Transportation Engineering, China University of Petroleum, Beijing, (China)

    2010-07-01

    The negative wave pressure method is one of the processes used to detect leaks on oil pipelines. The development of new leakage recognition processes is difficult because it is practically impossible to collect leakage pressure samples. The method of leakage feature extraction and the selection of the recognition model are also important in pipeline leakage detection. This study investigated a new feature extraction approach Singular Value Projection (SVP). It projects the singular value to a standard basis. A new pipeline recognition model based on the multi-class Support Vector Machines was also developed. It was found that SVP is a clear and concise recognition feature of the negative pressure wave. Field experiments proved that the model provided a high recognition accuracy rate. This approach to pipeline leakage detection based on the SVP and SVM has a high application value.

  1. A decade of user operation on the macromolecular crystallography MAD beamline ID14-4 at the ESRF.

    Science.gov (United States)

    McCarthy, Andrew A; Brockhauser, Sandor; Nurizzo, Didier; Theveneau, Pascal; Mairs, Trevor; Spruce, Darren; Guijarro, Matias; Lesourd, Marc; Ravelli, Raimond B G; McSweeney, Sean

    2009-11-01

    ID14-4 at the ESRF is the first tunable undulator-based macromolecular crystallography beamline that can celebrate a decade of user service. During this time ID14-4 has not only been instrumental in the determination of the structures of biologically important molecules but has also contributed significantly to the development of various instruments, novel data collection schemes and pioneering radiation damage studies on biological samples. Here, the evolution of ID14-4 over the last decade is presented, and some of the major improvements that were carried out in order to maintain its status as one of the most productive macromolecular crystallography beamlines are highlighted. The experimental hutch has been upgraded to accommodate a high-precision diffractometer, a sample changer and a large CCD detector. More recently, the optical hutch has been refurbished in order to improve the X-ray beam quality on ID14-4 and to incorporate the most modern and robust optical elements used at other ESRF beamlines. These new optical elements will be described and their effect on beam stability discussed. These studies may be useful in the design, construction and maintenance of future X-ray beamlines for macromolecular crystallography and indeed other applications, such as those planned for the ESRF upgrade.

  2. A decade of user operation on the macromolecular crystallography MAD beamline ID14-4 at the ESRF

    Energy Technology Data Exchange (ETDEWEB)

    McCarthy, Andrew A., E-mail: andrewmc@embl.fr; Brockhauser, Sandor [European Molecular Biology Laboratory, 6 rue Jules Horowitz, BP 181, 38042 Grenoble (France); Unit of Virus Host Cell Interactions, UJF-EMBL-CNRS, UMI 3265, 6 rue Jules Horowitz, 38042 Grenoble Cedex 9 (France); Nurizzo, Didier; Theveneau, Pascal; Mairs, Trevor; Spruce, Darren; Guijarro, Matias; Lesourd, Marc [European Synchrotron Radiation Facility, 6 rue Jules Horowitz, BP 220, 38042 Grenoble (France); Ravelli, Raimond B. G. [European Molecular Biology Laboratory, 6 rue Jules Horowitz, BP 181, 38042 Grenoble (France); McSweeney, Sean [European Synchrotron Radiation Facility, 6 rue Jules Horowitz, BP 220, 38042 Grenoble (France)

    2009-11-01

    The improvement of the X-ray beam quality achieved on ID14-4 by the installation of new X-ray optical elements is described. ID14-4 at the ESRF is the first tunable undulator-based macromolecular crystallography beamline that can celebrate a decade of user service. During this time ID14-4 has not only been instrumental in the determination of the structures of biologically important molecules but has also contributed significantly to the development of various instruments, novel data collection schemes and pioneering radiation damage studies on biological samples. Here, the evolution of ID14-4 over the last decade is presented, and some of the major improvements that were carried out in order to maintain its status as one of the most productive macromolecular crystallography beamlines are highlighted. The experimental hutch has been upgraded to accommodate a high-precision diffractometer, a sample changer and a large CCD detector. More recently, the optical hutch has been refurbished in order to improve the X-ray beam quality on ID14-4 and to incorporate the most modern and robust optical elements used at other ESRF beamlines. These new optical elements will be described and their effect on beam stability discussed. These studies may be useful in the design, construction and maintenance of future X-ray beamlines for macromolecular crystallography and indeed other applications, such as those planned for the ESRF upgrade.

  3. CSF Leakage "Radiology, Neuroradiology and Head and Neck, ENT"

    Directory of Open Access Journals (Sweden)

    Jalal Jalal Shokouhi

    2009-01-01

    Full Text Available Introduction: Leak of CSF is a relatively common complication in skull base fractures and it is rarely seen during skull base tumors and pituitary gland pathologies "Adenomas and empty sellae syndrome"."nThe common site of CSF leakage is related to the site of fracture but it is more common in cribriform plate fractures. Other sites are frontal sinus fractures and rarely sphenoid sinus lesions related to pituitary gland site pathology. Evaluation of the cribriform plate and the posterior wall of the frontal sinus is an imaging key point."nOther rare conditions of CSF leak are related to temporal bone fractures leading to otorrhea and in a paradoxical feature with rhinorrhea "intact tympanic membrane with temporal bone fracture and eustachian tube transmission of fluid"."nEthiology "nTrauma and skull base fractures epecially in the cribriform plate."nParanasal sinus fractures specially in the frontal and sphenoidal sinuses."nTemporal bone fractures."nEmpty sellae and intrasellar tumors."nPost-op stage in the skull base tumors."nDiagnosis"nNasal CSF leakage laboratory."nRadioneucleid imaging: This way is sensitive but non-specific."nMethylen blue injection into CSF via lumbar puncture "non-specific" and rarely used."nHigh resolution axial, coronal and sagittal reconstructed images of skull base as a modality of choice"nIn case of positive CSF leak but negative spiral ultra-high resolution CT in PNS, ethmoidal region and cribriform plate also temporal bone cuts we need linear and pleuridirectional X-ray tomography."nIn case of positive CSF leakage and negative radiology and imaging it needs exploration surgery to direct vision of anterior fossa floor bones for fracture."n-Companion complication could be recurrent meningitis."n- No 3D-CT or MRI is necessary for bone fractures but MRI could be"nnecessary for related brain contusion or soft tissue lesions and tumor."nX-ray CT-cisternography"nAlthough more than 90% of fractures could be detected by

  4. Characterization of CO2 leakage into the freshwater body

    Science.gov (United States)

    Singh, Ashok; Delfs, Jens-Olaf; Shao, Habing; Kolditz, Olaf

    2013-04-01

    Current research into Carbon dioxide Capture and Storage (CCS) is dominated by improving the CO2 storage capacity. However, potential leakage of CO2 can cause environmental problems, particularly if freshwater resources are nearby. In this regards, it is important to understand the chemistry of CO2 and the water system. CO2 leakage across the fluid interface (CO2 and water) is controlled by the difference in the partial pressure of CO2 in the storage and in the freshwater body. Once the CO2 is in solution, it equilibrates with the bicarbonate and carbonate ions. According to Millero (1994)such a system can be characterized by two parameters out of the four: total alkalinity (TA), total carbonate (TCO2), fugacity of CO2(fCO2) and pH. In the present modeling study, we are interested in the (i) CO2 leakage into a freshwater body (while injecting CO2 for storage) through an inclined fracture and (ii) characterization of the system by measuring fugacity of CO2 and pH. According to work presented by Singh et al. (2012), about 31% of injected CO2 leaks into the freshwater body. Solubility of CO2 in water follows Henry's law, while the Henry constant, K0 is calculated by an empirical relation developed by Murray and Riley (1971), which is a function of salinity and temperature. According to our results, pH and fugacity both appear to be a linear function of temperature. To simulate the discussed problem, a corresponding numerical module has been developed for multi-component fluid flow coupled with heat and mass transport processes. Governing equations and Volume Translated Peng-Robinson equations of state are implemented within the object-oriented finite element code OpenGeoSys (Kolditz et al., 2012; www.opengeosys.org). Primary variables are pressure, temperature and salinity which are obtained by solving the governing equations in a monolithic way The governing equations are discretized spatially within the context of a Galerkin approach, whereas the temporal

  5. Correlating antimicrobial activity and model membrane leakage induced by nylon-3 polymers and detergents.

    Science.gov (United States)

    Hovakeemian, Sara G; Liu, Runhui; Gellman, Samuel H; Heerklotz, Heiko

    2015-09-14

    Most antimicrobial peptides act upon target microorganisms by permeabilizing their membranes. The mode of action is often assessed by vesicle leakage experiments that use model membranes, with the assumption that biological activity correlates with the permeabilization of the lipid bilayer. The current work aims to extend the interpretation of vesicle leakage results and examine the correlation between vesicle leakage and antimicrobial activity. To this end, we used a lifetime-based leakage assay with calcein-loaded vesicles to study the membrane permeabilizing properties of a novel antifungal polymer poly-NM, two of its analogs, and a series of detergents. In conjunction, the biological activities of these compounds against Candida albicans were assessed and correlated with data from vesicle leakage. Poly-NM induces all-or-none leakage in polar yeast lipid vesicles at the polymer's MIC, 3 μg mL(-1). At this and higher concentrations, complete leakage after an initial lag time was observed. Concerted activity tests imply that this polymer acts independently of the detergent octyl glucoside (OG) for both vesicle leakage and activity against C. albicans spheroplasts. In addition, poly-NM was found to have negligible activity against zwitterionic vesicles and red blood cells. Our results provide a consistent, detailed picture of the mode of action of poly-NM: this polymer induces membrane leakage by electrostatic lipid clustering. In contrast, poly-MM:CO, a nylon-3 polymer comprised of both cationic and hydrophobic segments, seems to act by a different mechanism that involves membrane asymmetry stress. Vesicle leakage for this polymer is transient (limited to nylon-3 polymers we examined act via similar mechanisms; it is surprising that their mechanisms are so distinct. Some, but not all mechanisms of vesicle permeabilization allow for antimicrobial activity.

  6. The status of the macromolecular crystallography beamlines at the European Synchrotron Radiation Facility

    Science.gov (United States)

    Mueller-Dieckmann, Christoph; Bowler, Matthew W.; Carpentier, Philippe; Flot, David; McCarthy, Andrew A.; Nanao, Max H.; Nurizzo, Didier; Pernot, Petra; Popov, Alexander; Round, Adam; Royant, Antoine; de Sanctis, Daniele; von Stetten, David; Leonard, Gordon A.

    2015-04-01

    The European Synchrotron Radiation Facility (ESRF) is the oldest and most powerful 3rd generation synchrotron in Europe, providing X-rays to more than 40 experimental stations welcoming several thousand researchers per year. A major success story has been the ESRF's facilities for macromolecular crystallography (MX). These are grouped around 3 straight sections: On ID23 canted undulators accommodate ID23-1, a mini-focus tuneable energy end station and ID23-2, the world's first micro-focus beamline dedicated to MX; ID29 houses a single, mini-focus, tuneable energy end station; ID30 will provide three end stations for MX due in operation from mid-2014 to early 2015. Here, one branch of a canted X-ray source feeds two fixed-energy end stations (MASSIF-1, MASSIF-3). The second feeds ID30B, a variable focus, tuneable energy beamline. MASSIF-1 is optimised for automatic high-throughput experiments requiring a relatively large beam size at the sample position, MASSIF-3 is a high-intensity, micro-focus facility designed to complement ID23-2. All end stations are highly automated, equipped with sample mounting robots and large area, fast-readout photon-counting detectors. Experiment control and tracking is achieved via a combination of the MXCuBE2 graphical user interface and the ISPyB database, the former allowing user-friendly control of all beamline components, the latter providing data tracking before, after and during experiments.

  7. A test of macromolecular crystallization in microgravity: large well ordered insulin crystals.

    Science.gov (United States)

    Borgstahl, G E; Vahedi-Faridi, A; Lovelace, J; Bellamy, H D; Snell, E H

    2001-08-01

    Crystals of insulin grown in microgravity on Space Shuttle Mission STS-95 were extremely well ordered and unusually large (many >2 mm). The physical characteristics of six microgravity and six earth-grown crystals were examined by X-ray analysis employing superfine phi slicing and unfocused synchrotron radiation. This experimental setup allowed hundreds of reflections to be precisely examined from each crystal in a short period of time. The microgravity crystals were on average 34 times larger, had sevenfold lower mosaicity, had 54-fold higher reflection peak heights and diffracted to significantly higher resolution than their earth-grown counterparts. A single mosaic domain model could account for the observed reflection profiles in microgravity crystals, whereas data from earth crystals required a model with multiple mosaic domains. This statistically significant and unbiased characterization indicates that the microgravity environment was useful for the improvement of crystal growth and the resultant diffraction quality in insulin crystals and may be similarly useful for macromolecular crystals in general.

  8. RoboDiff: combining a sample changer and goniometer for highly automated macromolecular crystallography experiments

    Science.gov (United States)

    Nurizzo, Didier; Bowler, Matthew W.; Caserotto, Hugo; Dobias, Fabien; Giraud, Thierry; Surr, John; Guichard, Nicolas; Papp, Gergely; Guijarro, Matias; Mueller-Dieckmann, Christoph; Flot, David; McSweeney, Sean; Cipriani, Florent; Theveneau, Pascal; Leonard, Gordon A.

    2016-01-01

    Automation of the mounting of cryocooled samples is now a feature of the majority of beamlines dedicated to macromolecular crystallography (MX). Robotic sample changers have been developed over many years, with the latest designs increasing capacity, reliability and speed. Here, the development of a new sample changer deployed at the ESRF beamline MASSIF-1 (ID30A-1), based on an industrial six-axis robot, is described. The device, named RoboDiff, includes a high-capacity dewar, acts as both a sample changer and a high-accuracy goniometer, and has been designed for completely unattended sample mounting and diffraction data collection. This aim has been achieved using a high level of diagnostics at all steps of the process from mounting and characterization to data collection. The RoboDiff has been in service on the fully automated endstation MASSIF-1 at the ESRF since September 2014 and, at the time of writing, has processed more than 20 000 samples completely automatically. PMID:27487827

  9. The Effect of Attractive Interactions and Macromolecular Crowding on Crystallins Association.

    Directory of Open Access Journals (Sweden)

    Jiachen Wei

    Full Text Available In living systems proteins are typically found in crowded environments where their effective interactions strongly depend on the surrounding medium. Yet, their association and dissociation needs to be robustly controlled in order to enable biological function. Uncontrolled protein aggregation often causes disease. For instance, cataract is caused by the clustering of lens proteins, i.e., crystallins, resulting in enhanced light scattering and impaired vision or blindness. To investigate the molecular origins of cataract formation and to design efficient treatments, a better understanding of crystallin association in macromolecular crowded environment is needed. Here we present a theoretical study of simple coarse grained colloidal models to characterize the general features of how the association equilibrium of proteins depends on the magnitude of intermolecular attraction. By comparing the analytic results to the available experimental data on the osmotic pressure in crystallin solutions, we identify the effective parameters regimes applicable to crystallins. Moreover, the combination of two models allows us to predict that the number of binding sites on crystallin is small, i.e. one to three per protein, which is different from previous estimates. We further observe that the crowding factor is sensitive to the size asymmetry between the reactants and crowding agents, the shape of the protein clusters, and to small variations of intermolecular attraction. Our work may provide general guidelines on how to steer the protein interactions in order to control their association.

  10. Distinct Contribution of Electrostatics, Initial Conformational Ensemble, and Macromolecular Stability in RNA Folding

    Energy Technology Data Exchange (ETDEWEB)

    Laederach,A.; Shcherbakova, I.; Jonikas, M.; Altman, R.; Brenowitz, M.

    2007-01-01

    We distinguish the contribution of the electrostatic environment, initial conformational ensemble, and macromolecular stability on the folding mechanism of a large RNA using a combination of time-resolved 'Fast Fenton' hydroxyl radical footprinting and exhaustive kinetic modeling. This integrated approach allows us to define the folding landscape of the L-21 Tetrahymena thermophila group I intron structurally and kinetically from its earliest steps with unprecedented accuracy. Distinct parallel pathways leading the RNA to its native form upon its Mg2+-induced folding are observed. The structures of the intermediates populating the pathways are not affected by variation of the concentration and type of background monovalent ions (electrostatic environment) but are altered by a mutation that destabilizes one domain of the ribozyme. Experiments starting from different conformational ensembles but folding under identical conditions show that whereas the electrostatic environment modulates molecular flux through different pathways, the initial conformational ensemble determines the partitioning of the flux. This study showcases a robust approach for the development of kinetic models from collections of local structural probes.

  11. Macromolecular depletion modulates the binding of red blood cells to activated endothelial cells.

    Science.gov (United States)

    Yang, Yang; Koo, Stephanie; Lin, Cheryl Shuyi; Neu, Björn

    2010-09-01

    Adhesion of red blood cells (RBCs) to endothelial cells (ECs) is usually insignificant but an enhanced adhesion has been observed in various diseases associated with vascular complications. This abnormal adhesion under pathological conditions such as sickle cell disease has been correlated with increased levels of various plasma proteins but the detailed underlying mechanism(s) remains unclear. Usually it is assumed that the proadhesive effects of plasma proteins originate from ligand interactions cross-linking receptors on adjacent cells, but explicit results detailing binding sites or receptors for some proteins (e.g., fibrinogen) on either RBC or EC surfaces that would support this model are missing. In this study, the authors tested whether there is an alternative mechanism. Their results demonstrate that dextran 2 MDa promotes the adhesion of normal RBCs to thrombin-activated ECs and that this effect becomes more pronounced with increasing thrombin concentration or with prolonged thrombin incubation time. It is concluded that depletion interaction originating from nonadsorbing macromolecules (i.e., dextran) can modulate the adhesion of red blood cells to thrombin-activated EC. This study thereby suggests macromolecular depletion as an alternative mechanism for the adhesion-promoting effects of nonadsorbing plasma proteins. These findings should not only aid in getting a better understanding of diseases associated with vascular complications but should also have many potential applications in biomedical or biotechnological areas that require the control of cell-cell or cell surface interactions.

  12. Optimizing the spatial distribution of dose in X-ray macromolecular crystallography.

    Science.gov (United States)

    Zeldin, Oliver B; Gerstel, Markus; Garman, Elspeth F

    2013-01-01

    X-ray data collection for macromolecular crystallography can lead to highly inhomogeneous distributions of dose within the crystal volume for cases when the crystal is larger than the beam or when the beam is non-uniform (gaussian-like), particularly when crystal rotation is fully taken into account. Here the spatial distribution of dose is quantitatively modelled in order to compare the effectiveness of two dose-spreading data-collection protocols: helical scanning and translational collection. Their effectiveness in reducing the peak dose per unit diffraction is investigated via simulations for four common crystal shapes (cube, plate, long and short needles) and beams with a wide range of full width half maximum values. By inspection of the chosen metric, it is concluded that the optimum strategy is always to use as flat (top-hat) a beam as possible and to either match the beam size in both dimensions to the crystal, or to perform a helical scan with a beam which is narrow along the rotation axis and matched to the crystal size along the perpendicular axis. For crystal shapes where this is not possible, the reduction in peak dose per unit diffraction achieved through dose spreading is quantified and tabulated as a reference for experimenters.

  13. Diffraction cartography: applying microbeams to macromolecular crystallography sample evaluation and data collection.

    Science.gov (United States)

    Bowler, Matthew W; Guijarro, Matias; Petitdemange, Sebastien; Baker, Isabel; Svensson, Olof; Burghammer, Manfred; Mueller-Dieckmann, Christoph; Gordon, Elspeth J; Flot, David; McSweeney, Sean M; Leonard, Gordon A

    2010-08-01

    Crystals of biological macromolecules often exhibit considerable inter-crystal and intra-crystal variation in diffraction quality. This requires the evaluation of many samples prior to data collection, a practice that is already widespread in macromolecular crystallography. As structural biologists move towards tackling ever more ambitious projects, new automated methods of sample evaluation will become crucial to the success of many projects, as will the availability of synchrotron-based facilities optimized for high-throughput evaluation of the diffraction characteristics of samples. Here, two examples of the types of advanced sample evaluation that will be required are presented: searching within a sample-containing loop for microcrystals using an X-ray beam of 5 microm diameter and selecting the most ordered regions of relatively large crystals using X-ray beams of 5-50 microm in diameter. A graphical user interface developed to assist with these screening methods is also presented. For the case in which the diffraction quality of a relatively large crystal is probed using a microbeam, the usefulness and implications of mapping diffraction-quality heterogeneity (diffraction cartography) are discussed. The implementation of these techniques in the context of planned upgrades to the ESRF's structural biology beamlines is also presented.

  14. Competitive interactions of ligands and macromolecular crowders with maltose binding protein.

    Directory of Open Access Journals (Sweden)

    Andrew C Miklos

    Full Text Available Cellular signaling involves a cascade of recognition events occurring in a complex environment with high concentrations of proteins, polysaccharides, and other macromolecules. The influence of macromolecular crowders on protein binding affinity through hard-core repulsion is well studied, and possible contributions of protein-crowder soft attraction have been implicated recently. Here we present direct evidence for weak association of maltose binding protein (MBP with a polysaccharide crowder Ficoll, and that this association effectively competes with the binding of the natural ligand, maltose. Titration data over wide ranges of maltose and Ficoll concentrations fit well with a three-state competitive binding model. Broadening of MBP (1H-(15N TROSY spectra by the addition of Ficoll indicates weak protein-crowder association, and subsequent recovery of sharp NMR peaks upon addition of maltose indicates that the interactions of the crowder and the ligand with MBP are competitive. We hypothesize that, in the Escherichia coli periplasm, the competitive interactions of polysaccharides and maltose with MBP could allow MBP to shuttle between the peptidoglycan attached to the outer membrane and the ATP-binding cassette transporter in the inner membrane.

  15. Characterization of PEG-Like Macromolecular Coatings on Plasma Modified NiTi Alloy

    Science.gov (United States)

    Yang, Jun; Gao, Jiacheng; Chang, Peng; Wang, Jianhua

    2008-04-01

    A poly (ethylene glycol) (PEG-like) coating was developed to improve the biocompatibility of Nickel-Titanium (NiTi) alloy implants. The PEG-like macromolecular coatings were deposited on NiTi substrates at a room temperature of 298 K through a ECR (electron-cyclotron resonance) cold-plasma enhanced chemical vapor deposition method using tetraglyme (CH3-O-(CH2-CH2-O)4-CH3) as a precursor. A power supply with a frequency of 2.45 GHz was applied to ignite the plasma with Ar(argon) used as the carrier gas. Based on the atomic force microscopy (AFM) studies, a thin smooth coating on NiTi substrates with highly amorphous functional groups on the modified NiTi surfaces were mainly the same accumulated stoichiometric ratio of C and O with PEG. The vitro studies showed that platelet-rich plasma (PRP) adsorption on the modified NiTi alloy surface was significantly reduced. This study indicated that plasma surface modification changes the surface components of NiTi alloy and subsequently improves its biocompatibility.

  16. Characterization of PEG-Like Macromolecular Coatings on Plasma Modified NiTi Alloy

    Institute of Scientific and Technical Information of China (English)

    YANG Jun; GAO Jiacheng; CHANG Peng; WANG Jianhua

    2008-01-01

    A poly(ethylene glycol) (PEG-like) coating was developed to improve the biocompatibility of Nickel-Titanium (NiTi) alloy implants. The PEG-like macromolecular coatings were deposited on NiTi substrates at a room temperature of 298 K through a ECR (electron-cyclotron resonance) cold-plasma .enhanced chemical vapor deposition method using tetraglyme (CH3-O(CH2-CH2-O)4-CH3) as a precursor. A power supply with a frequency of 2.45 GHz was applied to ignite the plasma with Ar(argon) used as the carrier gas. Based on the atomic force microscopy (AFM) studies, a thin smooth coating on NiTi substrates with highly amorphous functional groups on the modified NiTi surfaces were mainly the same accumulated stoichiometric ratio of C and O with PEG. The vitro studies showed that platelet-rich plasma (PRP) adsorption on the modified NiTi alloy surface was significantly reduced. This study indicated that plasma surface modification changes the surface components of NiTi alloy and subsequently improves its biocompatibility.

  17. Effects of sound exposure on the growth and intracellular macromolecular synthesis of E. coli k-12

    Directory of Open Access Journals (Sweden)

    Shaobin Gu

    2016-04-01

    Full Text Available Microbes, as one of the primary producers of the biosphere, play an important role in ecosystems. Exploring the mechanism of adaptation and resistance of microbial population to various environmental factors has come into focus in the fields of modern microbial ecology and molecular ecology. However, facing the increasingly serious problem of acoustic pollution, very few efforts have been put forth into studying the relation of single cell organisms and sound field exposure. Herein, we studied the biological effects of sound exposure on the growth of E. coli K-12 with different acoustic parameters. The effects of sound exposure on the intracellular macromolecular synthesis and cellular morphology of E. coli K-12 were also analyzed and discussed. Experimental results indicated that E. coli K-12 exposed to sound waves owned a higher biomass and a faster specific growth rate compared to the control group. Also, the average length of E. coli K-12 cells increased more than 27.26%. The maximum biomass and maximum specific growth rate of the stimulation group by 8000 Hz, 80dB sound wave was about 1.7 times and 2.5 times that of the control group, respectively. Moreover, it was observed that E. coli K-12 can respond rapidly to sound stress at both the transcriptional and posttranscriptional levels by promoting the synthesis of intracellular RNA and total protein. Some potential mechanisms may be involved in the responses of bacterial cells to sound stress.

  18. FitEM2EM--tools for low resolution study of macromolecular assembly and dynamics.

    Directory of Open Access Journals (Sweden)

    Ziv Frankenstein

    Full Text Available Studies of the structure and dynamics of macromolecular assemblies often involve comparison of low resolution models obtained using different techniques such as electron microscopy or atomic force microscopy. We present new computational tools for comparing (matching and docking of low resolution structures, based on shape complementarity. The matched or docked objects are represented by three dimensional grids where the value of each grid point depends on its position with regard to the interior, surface or exterior of the object. The grids are correlated using fast Fourier transformations producing either matches of related objects or docking models depending on the details of the grid representations. The procedures incorporate thickening and smoothing of the surfaces of the objects which effectively compensates for differences in the resolution of the matched/docked objects, circumventing the need for resolution modification. The presented matching tool FitEM2EMin successfully fitted electron microscopy structures obtained at different resolutions, different conformers of the same structure and partial structures, ranking correct matches at the top in every case. The differences between the grid representations of the matched objects can be used to study conformation differences or to characterize the size and shape of substructures. The presented low-to-low docking tool FitEM2EMout ranked the expected models at the top.

  19. Involvement of lysosomes in the uptake of macromolecular material by bloodstream forms of Trypanosoma brucei.

    Science.gov (United States)

    Opperdoes, F R; Van Roy, J

    1982-09-01

    To investigate whether the lysosomes of Trypanosoma brucei are capable of uptake of macromolecules after internalization by the cell, we used Triton WR-1339, a non-digestible macromolecular compound, which is known to cause a marked decrease in the density of hepatic lysosomes due to massive intralysosomal storage. Intraperitoneal administration of 0.4 g/kg Triton WR-1339 to rats infected with T. brucei led to the development of a large vacuole in the trypanosomes between nucleus and kinetoplast within 22 h. Higher doses (2 g/kg) led to the disappearance of the trypanosomes from the blood and resulted in permanent cures (greater than 100 days). Lysosomes isolated from the trypanosomes of animals treated with a sub-curative dose showed a decrease in equilibrium density of 0.03 g/cm3 in sucrose gradients. These lysosomes were partly damaged as evidenced by a reduction in latency and an increase in the non-sedimentable part of lysosomal enzymes. We conclude that acid proteinase and alpha-mannosidase-containing organelles of T. brucei take up exogenous macromolecules and must therefore be considered as true lysosomes and that Triton WR-1339 acts in T. brucei as a true lysosomotropic drug. Its trypanocidal action probably results from an interference with lysosomal function.

  20. Macromolecular crowding and the steady-state kinetics of malate dehydrogenase.

    Science.gov (United States)

    Poggi, Christopher G; Slade, Kristin M

    2015-01-20

    To understand how macromolecular crowding affects enzyme activity, we quantified the Michaelis-Menten kinetics of mitochondrial malate dehydrogenase (MDH) in the presence of hen egg white (HEW), lysozyme, bovine serum albumin (BSA), gum arabic, poly(vinylpyrrolidone) (PVP), and dextrans of various molecular weights. Although crowding tended to decrease Km and Vmax values, the magnitude depended on the crowding agent, reaction direction, and isozyme (mitochondrial porcine heart or thermophlic TaqMDH from Thermus flavus). Crowding slowed oxaloacetate reduction more significantly than malate oxidation, which may suggest that mitochondrial enzymes have evolved to function optimally under the crowded constraints in which they are immersed. Since direct comparisons of neutral to charged crowders are underrepresented in the literature, we performed these studies and found that neutral crowding agents lowered Vmax values more than charged crowders of similar size. The exception was hen egg white, a mixture of charged proteins that caused the largest observed decreases in both Km and Vmax. Finally, the data provide insight about the mechanism by corroborating MDH subunit dependence.

  1. Proteinase K activity determination with β-galactosidase as sensitive macromolecular substrate.

    Science.gov (United States)

    Ghéczy, Nicolas; Küchler, Andreas; Walde, Peter

    2016-11-15

    Proteinase K from Engyodontium album (proK) is a relatively unspecific serine endopeptidase which is known to attack proteins yet in their native states. If the attacked protein is an enzyme, even a partial hydrolysis by proK may lead to an inactivation of the enzyme, which can be monitored by measuring the loss of catalytic activity of the attacked enzyme. E. coli β-galactosidase (β-Gal) was used in this work as such enzyme. It was found to be a convenient and sensitive macromolecular model substrate for comparing the "native protein-attacking ability" of free and immobilized proK at pH = 7.0 and 23 °C. The β-Gal activity was measured spectrophotometrically with o-nitrophenyl-β-galactopyranoside. Reproducible proK determinations were possible for as little as 4.3 ng proK by using a proK analyte solution of 10 nM. Compared to free proK, immobilized proK was much less efficient in inactivating β-Gal, most likely due to a decreased mobility of immobilized proK and a restricted accessibility of β-Gal to the active site of proK. Worth noting is, that under conditions at which β-Gal was completely inactivated by proK, the activity of hen egg lysozyme, horseradish peroxidase, or Aspergillus sp. glucose oxidase remained unaltered.

  2. SCIENTIFIC PRINCIPLES FOR MODIFICATION OF WATER-SOLUBLE POLYMERS. FORMATION OF MACROMOLECULAR COMPLEXES

    Institute of Scientific and Technical Information of China (English)

    1998-01-01

    The study of nanosecond dynamics of macromolecules with the luminescent methods make it possible to investigate the formation and functioning of polymeric complexes, polymeric conjugates and macromolecular metal complexes, which are widely used for solving many practical tasks. The nanosecond dynamics of macromolecules are a highly sensitive indicator of interpolymer complexes (IPC) formation. It enables us to solve the problems of studying IPC formation and stability and to investigate the interpolymer reactions of exchange and substitution. The investigation of changes in the rotational mobility of globular protein molecules as a whole makes it possible to determine the complex composition and its stability, and to control the course of polymer-protein conjugate formstion reaction. The nanosecond dynamics of polymers interacting with surfacants' ions (S)are the sensitive indicator of the S-polymer complex formation. A method for determining the equilibrium constants of the S-polymer complex formation was developed on the basis of the study of polymer chains mobility. It is established that nanosecond dynamics influences the course of chemical reactions in polymer chains. Moreover, the marked effect of the nanosecond dynamics is also revealed in the study of photophysical processes (the formation of excimers and energy migration of electron excitation) in polymers with photoactive groups. It was found that the efficiency of both processes increases with increasing the mobility of side chains, the carriers of photoactive groups.

  3. Macromolecular scaffolding: the relationship between nanoscale architecture and function in multichromophoric arrays for organic electronics.

    Science.gov (United States)

    Palermo, Vincenzo; Schwartz, Erik; Finlayson, Chris E; Liscio, Andrea; Otten, Matthijs B J; Trapani, Sara; Müllen, Klaus; Beljonne, David; Friend, Richard H; Nolte, Roeland J M; Rowan, Alan E; Samorì, Paolo

    2010-02-23

    The optimization of the electronic properties of molecular materials based on optically or electrically active organic building blocks requires a fine-tuning of their self-assembly properties at surfaces. Such a fine-tuning can be obtained on a scale up to 10 nm by mastering principles of supramolecular chemistry, i.e., by using suitably designed molecules interacting via pre-programmed noncovalent forces. The control and fine-tuning on a greater length scale is more difficult and challenging. This Research News highlights recent results we obtained on a new class of macromolecules that possess a very rigid backbone and side chains that point away from this backbone. Each side chain contains an organic semiconducting moiety, whose position and electronic interaction with neighboring moieties are dictated by the central macromolecular scaffold. A combined experimental and theoretical approach has made it possible to unravel the physical and chemical properties of this system across multiple length scales. The (opto)electronic properties of the new functional architectures have been explored by constructing prototypes of field-effect transistors and solar cells, thereby providing direct insight into the relationship between architecture and function.

  4. A graph theoretical approach for assessing bio-macromolecular complex structural stability.

    Science.gov (United States)

    Del Carpio, Carlos Adriel; Iulian Florea, Mihai; Suzuki, Ai; Tsuboi, Hideyuki; Hatakeyama, Nozomu; Endou, Akira; Takaba, Hiromitsu; Ichiishi, Eiichiro; Miyamoto, Akira

    2009-11-01

    Fast and proper assessment of bio macro-molecular complex structural rigidity as a measure of structural stability can be useful in systematic studies to predict molecular function, and can also enable the design of rapid scoring functions to rank automatically generated bio-molecular complexes. Based on the graph theoretical approach of Jacobs et al. [Jacobs DJ, Rader AJ, Kuhn LA, Thorpe MF (2001) Protein flexibility predictions using graph theory. Proteins: Struct Funct Genet 44:150-165] for expressing molecular flexibility, we propose a new scheme to analyze the structural stability of bio-molecular complexes. This analysis is performed in terms of the identification in interacting subunits of clusters of flappy amino acids (those constituting regions of potential internal motion) that undergo an increase in rigidity at complex formation. Gains in structural rigidity of the interacting subunits upon bio-molecular complex formation can be evaluated by expansion of the network of intra-molecular inter-atomic interactions to include inter-molecular inter-atomic interaction terms. We propose two indices for quantifying this change: one local, which can express localized (at the amino acid level) structural rigidity, the other global to express overall structural stability for the complex. The new system is validated with a series of protein complex structures reported in the protein data bank. Finally, the indices are used as scoring coefficients to rank automatically generated protein complex decoys.

  5. Enzyme activity determination on macromolecular substrates by isothermal titration calorimetry: application to mesophilic and psychrophilic chitinases.

    Science.gov (United States)

    Lonhienne, T; Baise, E; Feller, G; Bouriotis, V; Gerday, C

    2001-02-09

    Isothermal titration calorimetry has been applied to the determination of the kinetic parameters of chitinases (EC 3.2.1.14) by monitoring the heat released during the hydrolysis of chitin glycosidic bonds. Experiments were carried out using two different macromolecular substrates: a soluble polymer of N-acetylglucosamine and the insoluble chitin from crab shells. Different experimental temperatures were used in order to compare the thermodependence of the activity of two chitinases from the psychrophile Arthrobacter sp. TAD20 and of chitinase A from the mesophile Serratia marcescens. The method allowed to determine unequivocally the catalytic rate constant k(cat), the activation energy (E(a)) and the thermodynamic activation parameters (DeltaG(#), DeltaH(#), DeltaS(#)) of the chitinolytic reaction on the soluble substrate. The catalytic activity has also been determined on insoluble chitin, which displays an effect of substrate saturation by chitinases. On both substrates, the thermodependence of the activity of the psychrophilic chitinases was lower than that observed with the mesophilic counterpart.

  6. Interaction of wall shear stress magnitude and gradient in the prediction of arterial macromolecular permeability.

    Science.gov (United States)

    LaMack, Jeffrey A; Himburg, Heather A; Li, Xue-Mei; Friedman, Morton H

    2005-04-01

    Large spatial shear stress gradients have anecdotally been associated with early atherosclerotic lesion susceptibility in vivo and have been proposed as promoters of endothelial cell dysfunction in vitro. Here, experiments are presented in which several measures of the fluid dynamic shear stress, including its gradient, at the walls of in vivo porcine iliac arteries, are correlated against the transendothelial macromolecular permeability of the vessels. The fluid dynamic measurements are based on postmortem vascular casts, and permeability is measured from Evans blue dye (EBD) uptake. Time-averaged wall shear stress (WSS), as well as a new parameter termed maximum gradient stress (MGS) that describes the spatial shear stress gradient due to flow acceleration at a given point, are mapped for each artery and compared on a point-by-point basis to the corresponding EBD patterns. While there was no apparent relation between MGS and EBD uptake, a composite parameter, WSS(-0.11) MGS(0.044), was highly correlated with permeability. Notwithstanding the small exponents, the parameter varied widely within the region of interest. The results suggest that sites exposed to low wall shear stresses are more likely to exhibit elevated permeability, and that this increase is exacerbated in the presence of large spatial shear stress gradients.

  7. Temperature sensitivity of soil microbial communities: An application of macromolecular rate theory to microbial respiration

    Science.gov (United States)

    Alster, Charlotte J.; Koyama, Akihiro; Johnson, Nels G.; Wallenstein, Matthew D.; Fischer, Joseph C.

    2016-06-01

    There is compelling evidence that microbial communities vary widely in their temperature sensitivity and may adapt to warming through time. To date, this sensitivity has been largely characterized using a range of models relying on versions of the Arrhenius equation, which predicts an exponential increase in reaction rate with temperature. However, there is growing evidence from laboratory and field studies that observe nonmonotonic responses of reaction rates to variation in temperature, indicating that Arrhenius is not an appropriate model for quantitatively characterizing temperature sensitivity. Recently, Hobbs et al. (2013) developed macromolecular rate theory (MMRT), which incorporates thermodynamic temperature optima as arising from heat capacity differences between isoenzymes. We applied MMRT to measurements of respiration from soils incubated at different temperatures. These soils were collected from three grassland sites across the U.S. Great Plains and reciprocally transplanted, allowing us to isolate the effects of microbial community type from edaphic factors. We found that microbial community type explained roughly 30% of the variation in the CO2 production rate from the labile C pool but that temperature and soil type were most important in explaining variation in labile and recalcitrant C pool size. For six out of the nine soil × inoculum combinations, MMRT was superior to Arrhenius. The MMRT analysis revealed that microbial communities have distinct heat capacity values and temperature sensitivities sometimes independent of soil type. These results challenge the current paradigm for modeling temperature sensitivity of soil C pools and understanding of microbial enzyme dynamics.

  8. Effect of the macromolecular architecture of biodegradable polyurethanes on the controlled delivery of ocular drugs.

    Science.gov (United States)

    da Silva, Gisele Rodrigues; da Silva Cunha, Armando; Ayres, Eliane; Oréfice, Rodrigo L

    2009-02-01

    Controlled delivery of drugs is a major issue in the treatment of ocular diseases, such as in the treatment of uveitis. In this study, dexamethasone acetate, an important type of corticoid used in the treatment of some uveitis, was incorporated into biodegradable polyurethanes (PU) having different macromolecular architectures. The biodegradable polyurethanes were obtained by preparing PU aqueous dispersions having poly(caprolactone) and/or poly(ethylene glycol) as soft segments. The drug was incorporated into the polymer by dissolving it in the PU aqueous dispersion. FTIR results showed the presence of the drug in the polymer with its original chemical structure. Small angle X-ray scattering (SAXS) results were explored to show that the incorporation of dexamethasone acetate led to the modification of the nanostructure of the polyurethane having only poly(caprolactone) as the soft segment, while the drug did not change significantly the microphase separated structure of PU having both poly(caprolactone) and poly(ethylene glycol) as soft segments. The evaluation of the release of the drug in vitro demonstrated that the obtained biodegradable polyurethanes were well succeeded in delivering dexamethasone acetate at an almost constant rate for 53 weeks. The presence of poly(ethylene glycol) together with poly(caprolactone) as soft segment in biodegradable PU was able to increase the rate of dexamethasone acetate release when compared to the rate of drug release from PU having only poly(caprolactone).

  9. Using support vector machines to improve elemental ion identification in macromolecular crystal structures

    Energy Technology Data Exchange (ETDEWEB)

    Morshed, Nader [University of California, Berkeley, CA 94720 (United States); Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Echols, Nathaniel, E-mail: nechols@lbl.gov [Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Adams, Paul D., E-mail: nechols@lbl.gov [Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); University of California, Berkeley, CA 94720 (United States)

    2015-05-01

    A method to automatically identify possible elemental ions in X-ray crystal structures has been extended to use support vector machine (SVM) classifiers trained on selected structures in the PDB, with significantly improved sensitivity over manually encoded heuristics. In the process of macromolecular model building, crystallographers must examine electron density for isolated atoms and differentiate sites containing structured solvent molecules from those containing elemental ions. This task requires specific knowledge of metal-binding chemistry and scattering properties and is prone to error. A method has previously been described to identify ions based on manually chosen criteria for a number of elements. Here, the use of support vector machines (SVMs) to automatically classify isolated atoms as either solvent or one of various ions is described. Two data sets of protein crystal structures, one containing manually curated structures deposited with anomalous diffraction data and another with automatically filtered, high-resolution structures, were constructed. On the manually curated data set, an SVM classifier was able to distinguish calcium from manganese, zinc, iron and nickel, as well as all five of these ions from water molecules, with a high degree of accuracy. Additionally, SVMs trained on the automatically curated set of high-resolution structures were able to successfully classify most common elemental ions in an independent validation test set. This method is readily extensible to other elemental ions and can also be used in conjunction with previous methods based on a priori expectations of the chemical environment and X-ray scattering.

  10. Visualization of X-ray Beam Using CdWO4 Crystal for Macromolecular Crystallography

    Directory of Open Access Journals (Sweden)

    Kazimierz J. Gofron

    2011-12-01

    Full Text Available In synchrotron diffraction experiments, it is typically assumed that the X-ray beam at the sample position is uniform, stable and has dimensions that are controlled by the focus and slits settings. As might be expected, this process is much more complex. We present here an investigation of the properties of a synchrotron X-ray beam at the sample position. The X-ray beam is visualized with a single crystal scintillator that converts X-ray photons into visible light photons, which can be imaged using Structure Biology Center (SBC on-axis and off-axis microscope optics. The X-ray penetration is dependent on the composition of the scintillator (especially the effective Z, and X-ray energy. Several scintillators have been used to visualize X-ray beams. Here we compare CdWO4, PbWO4, Bi4Ge3O12, Y3Al5O12:Ce (YAG:Ce, and Gd2O2S:Tb (phosphor. We determined that scintillator crystals made of CdWO4 and similar high-Z materials are best suited for the energy range (7–20 keV and are most suitable for beam visualization for macromolecular crystallography applications. These scintillators show excellent absorption, optical, and mechanical properties.

  11. IMAGINE: first neutron protein structure and new capabilities for neutron macromolecular crystallography

    Energy Technology Data Exchange (ETDEWEB)

    Munshi, Parthapratim [ORNL; Myles, Dean A A [ORNL; Robertson, Lee [ORNL; Stoica, Alexandru Dan [ORNL; Crow, Lowell [ORNL; Kovalevskyi, Andrii Y [ORNL; Koritsanszky, Tibor S [ORNL; Chakoumakos, Bryan C [ORNL; Blessing, Robert [Hauptman-Woodward Medical Research Institute; Meilleur, Flora [ORNL

    2013-01-01

    We report the first high resolution neutron protein structure of perdeuterated rubredoxin from Pyrococcus furiosus (PfRd) determined using the new IMAGINE macromolecular neutron crystallography instrument at the Oak Ridge National Laboratory. Neutron diffraction data extending to 1.65 resolution were collected from a relatively small 0.7 mm3 PfRd crystal using 2.5 days (60 h) of beam time. The refined structure contains 371 out of 391, or 95%, of the deuterium atoms of the protein, and 58 solvent molecules. The IMAGINE instrument is designed to provide neutron data at or near atomic resolutions (1.5 ) from crystals with volume < 1.0 mm3 and with unit cell edges < 100 . Beam line features include elliptical focusing mirrors that deliver 3x107 n s-1 cm-2 into a 3.5 x 2.0 mm2 focal spot at the sample position, and variable short and long wavelength cutoff optics that provide automated exchange between multiple wavelength configurations ( min=2.0 , 2.8 , 3.3 - max =3.0 , 4.0 , 4.5 , ~20 ). Notably, the crystal used to collect this PfRd data is 5-10 times smaller than has been previously reported.

  12. Influence of temperature and macromolecular mobility on sorption of TCE on humic acid coated mineral surfaces.

    Science.gov (United States)

    Bell, Katherine Young; LeBoeuf, Eugene J

    2013-01-01

    This study demonstrates differences in sorptive capacity of volatile organic compound (VOC) trichloroethylene (TCE) onto natural organic matter (NOM) coated and uncoated mineral surfaces above and below the NOM glass transition temperature. TCE sorption isotherms for dry NOM-mineral systems below the NOM glass transition temperature (T(g)) demonstrated sorption behavior characteristic of micropore filling, with sorption capacities reduced relative to uncoated mineral matrices. Such differences were not entirely associated with differences in surface areas of the coated and uncoated mineral matrices, but were likely associated with either a blockage of pore space available to the VOC or a kinetic limitation that does not allow the VOC access to the internal porosity of the model soil within the time periods of the experiment. TCE sorption in dry NOM-mineral matrices above the T(g), however, was described in terms of sorption within a more fluid, macromolecular dissolution medium that does not hinder access to mineral surfaces. Such observations have potential important implications for modeling the fate and transport of VOCs in soils and sediment systems.

  13. Synthesis and Self-Assembly of Amphiphilic Triblock Terpolymers with Complex Macromolecular Architecture

    KAUST Repository

    Polymeropoulos, George

    2015-11-25

    Two star triblock terpolymers (PS-b-P2VP-b-PEO)3 and one dendritic-like terpolymer [PS-b-P2VP-b-(PEO)2]3 of PS (polystyrene), P2VP (poly(2-vinylpyridine)), and PEO (poly(ethylene oxide)), never reported before, were synthesized by combining atom transfer radical and anionic polymerizations. The synthesis involves the transformation of the -Br groups of the previously reported Br-terminated 3-arm star diblock copolymers to one or two -OH groups, followed by anionic polymerization of ethylene oxide to afford the star or dendritic structure, respectively. The well-defined structure of the terpolymers was confirmed by static light scattering, size exclusion chromatography, and NMR spectroscopy. The self-assembly in solution and the morphology in bulk of the terpolymers, studied by dynamic light scattering and transmission electron microscopy, respectively, reveal new insights in the phase separation of these materials with complex macromolecular architecture. © 2015 American Chemical Society.

  14. Discovering free energy basins for macromolecular systems via guided multiscale simulation.

    Science.gov (United States)

    Sereda, Yuriy V; Singharoy, Abhishek B; Jarrold, Martin F; Ortoleva, Peter J

    2012-07-26

    An approach for the automated discovery of low free energy states of macromolecular systems is presented. The method does not involve delineating the entire free energy landscape but proceeds in a sequential free energy minimizing state discovery; i.e., it first discovers one low free energy state and then automatically seeks a distinct neighboring one. These states and the associated ensembles of atomistic configurations are characterized by coarse-grained variables capturing the large-scale structure of the system. A key facet of our approach is the identification of such coarse-grained variables. Evolution of these variables is governed by Langevin dynamics driven by thermal-average forces and mediated by diffusivities, both of which are constructed by an ensemble of short molecular dynamics runs. In the present approach, the thermal-average forces are modified to account for the entropy changes following from our knowledge of the free energy basins already discovered. Such forces guide the system away from the known free energy minima, over free energy barriers, and to a new one. The theory is demonstrated for lactoferrin, known to have multiple energy-minimizing structures. The approach is validated using experimental structures and traditional molecular dynamics. The method can be generalized to enable the interpretation of nanocharacterization data (e.g., ion mobility-mass spectrometry, atomic force microscopy, chemical labeling, and nanopore measurements).

  15. Feasibility study of tank leakage mitigation using subsurface barriers

    Energy Technology Data Exchange (ETDEWEB)

    Treat, R.L.; Peters, B.B.; Cameron, R.J.; McCormak, W.D.; Trenkler, T.; Walters, M.F. [Ensearch Environmental, Inc. (United States); Rouse, J.K.; McLaughlin, T.J. [Bovay Northwest, Inc., Richland, WA (United States); Cruse, J.M. [Westinghouse Hanford Co., Richland, WA (United States)

    1994-09-21

    The US Department of Energy (DOE) has established the Tank Waste Remediation System (TWRS) to satisfy manage and dispose of the waste currently stored in the underground storage tanks. The retrieval element of TWRS includes a work scope to develop subsurface impermeable barriers beneath SSTs. The barriers could serve as a means to contain leakage that may result from waste retrieval operations and could also support site closure activities by facilitating cleanup. Three types of subsurface barrier systems have emerged for further consideration: (1) chemical grout, (2) freeze walls, and (3) desiccant, represented in this feasibility study as a circulating air barrier. This report contains analyses of the costs and relative risks associated with combinations retrieval technologies and barrier technologies that from 14 alternatives. Eight of the alternatives include the use of subsurface barriers; the remaining six nonbarrier alternative are included in order to compare the costs, relative risks and other values of retrieval with subsurface barriers. Each alternative includes various combinations of technologies that can impact the risks associated with future contamination of the groundwater beneath the Hanford Site to varying degrees. Other potential risks associated with these alternatives, such as those related to accidents and airborne contamination resulting from retrieval and barrier emplacement operations, are not quantitatively evaluated in this report.

  16. Airborne Detection and Tracking of Geologic Leakage Sites

    Science.gov (United States)

    Jacob, Jamey; Allamraju, Rakshit; Axelrod, Allan; Brown, Calvin; Chowdhary, Girish; Mitchell, Taylor

    2014-11-01

    Safe storage of CO2 to reduce greenhouse gas emissions without adversely affecting energy use or hindering economic growth requires development of monitoring technology that is capable of validating storage permanence while ensuring the integrity of sequestration operations. Soil gas monitoring has difficulty accurately distinguishing gas flux signals related to leakage from those associated with meteorologically driven changes of soil moisture and temperature. Integrated ground and airborne monitoring systems are being deployed capable of directly detecting CO2 concentration in storage sites. Two complimentary approaches to detecting leaks in the carbon sequestration fields are presented. The first approach focuses on reducing the requisite network communication for fusing individual Gaussian Process (GP) CO2 sensing models into a global GP CO2 model. The GP fusion approach learns how to optimally allocate the static and mobile sensors. The second approach leverages a hierarchical GP-Sigmoidal Gaussian Cox Process for airborne predictive mission planning to optimally reducing the entropy of the global CO2 model. Results from the approaches will be presented.

  17. Agulhas leakage dynamics affects decadal variability in Atlantic overturning circulation.

    Science.gov (United States)

    Biastoch, A; Böning, C W; Lutjeharms, J R E

    2008-11-27

    Predicting the evolution of climate over decadal timescales requires a quantitative understanding of the dynamics that govern the meridional overturning circulation (MOC). Comprehensive ocean measurement programmes aiming to monitor MOC variations have been established in the subtropical North Atlantic (RAPID, at latitude 26.5 degrees N, and MOVE, at latitude 16 degrees N) and show strong variability on intraseasonal to interannual timescales. Observational evidence of longer-term changes in MOC transport remains scarce, owing to infrequent sampling of transoceanic sections over past decades. Inferences based on long-term sea surface temperature records, however, supported by model simulations, suggest a variability with an amplitude of +/-1.5-3 Sv (1 Sv = 10(6) m(3) s(-1)) on decadal timescales in the subtropics. Such variability has been attributed to variations of deep water formation in the sub-arctic Atlantic, particularly the renewal rate of Labrador Sea Water. Here we present results from a model simulation that suggest an additional influence on decadal MOC variability having a Southern Hemisphere origin: dynamic signals originating in the Agulhas leakage region at the southern tip of Africa. These contribute a MOC signal in the tropical and subtropical North Atlantic that is of the same order of magnitude as the northern source. A complete rationalization of observed MOC changes therefore also requires consideration of signals arriving from the south.

  18. Characteristics of tip-leakage flow in an axial fan

    Science.gov (United States)

    Park, Keuntae; Choi, Haecheon; Choi, Seokho; Sa, Yongcheol

    2014-11-01

    An axial fan with a shroud generates complicated vortical structures by the interaction of the axial flow with the fan blades and shroud near the blade tips. Large eddy simulation (LES) is performed for flow through a forward-swept axial fan, operating at the design condition of Re = 547,000 based on the radius of blade tip and the tip velocity. A dynamic global model (Lee et al. 2010) is used for a subgrid-scale model, and an immersed boundary method in a non-inertial reference frame (Kim & Choi 2006) is adopted for the present simulation. It is found that two vortical structures are formed near the blade tip: the main tip leakage vortex (TLV) and the auxiliary TLV. The main TLV is initiated near the leading edge, develops downstream, and impinges on the pressure surface of the next blade, where the pressure fluctuations and turbulence intensity become high. On the other hand, the auxiliary TLV is initiated at the aft part of the blade but is relatively weak such that it merges with the main TLV. Supported by the KISTI Supercomputing Center (KSC-2014-C2-014).

  19. Structural and leakage integrity assessment of WWER steam generator tubes

    Energy Technology Data Exchange (ETDEWEB)

    Splichal, K.; Otruba, J. [Nuclear Research Inst., Rez (Switzerland)

    1997-12-31

    The integrity of heat exchange tubes may influence the life-time of WWER steam generators and appears to be an important criterion for the evaluation of their safety and operational reliability. The basic requirement is to assure a very low probability of radioactive water leakage, preventing unstable crack growth and sudden tube rupture. These requirements led to development of permissible limits for primary to secondary leak evolution and heat exchange tubes plugging based on eddy current test inspection. The stress corrosion cracking and pitting are the main corrosion damage of WWER heat exchange tubes and are initiated from the outer surface. They are influenced by water chemistry, temperature and tube wall stress level. They take place under crevice corrosion condition and are indicated especially (1) under the tube support plates, where up to 90-95 % of defects detected by the ECT method occur, and (2) on free spans under tube deposit layers. Both the initiation and crack growth cause thinning of the tube wall and lead to part thickness cracks and through-wall cracks, oriented above all in the axial direction. 10 refs.

  20. Investigation of Underground Hydrocarbon Leakage using Ground Penetrating Radar

    Science.gov (United States)

    Srigutomo, Wahyu; Trimadona; Agustine, Eleonora

    2016-08-01

    Ground Penetrating Radar (GPR) survey was carried out in several petroleum plants to investigate hydrocarbon contamination beneath the surface. The hydrocarbon spills are generally recognized as Light Non-Aqueous Phase Liquids (LNAPL) if the plume of leakage is distributed in the capillary fringe above the water table and as Dense Non-Aqueous Phase Liquids (DNAPL) if it is below the water table. GPR antennas of 200 MHz and 400 MHz were deployed to obtain clear radargrams until 4 m deep. In general, the interpreted radargram sections indicate the presence of surface concrete layer, the compacted silty soill followed by sand layer and the original clayey soil as well as the water table. The presence of hydrocarbon plumes are identified as shadow zones (radar velocity and intensity contrasts) in the radargram that blur the layering pattern with different intensity of reflected signal. Based on our results, the characteristic of the shadow zones in the radargram is controlled by several factors: types of hydrocarbon (fresh or bio-degraded), water moisture in the soil, and clay content which contribute variation in electrical conductivity and dielectric constants of the soil.

  1. Effects of switch leakages upon Nimbus-7 SMMR calibration

    Science.gov (United States)

    Han, Daesoo; Kim, Seung T.

    1988-01-01

    A calibration model for the Nimbus 7 Scanning Multichannel Microwave Radiometer (SMMR) is studied. This model not only removes major drawbacks of the current calibration model but also helps in the understanding of the performance degradation of the aging instrument. The current Nimbus 7 SMMR calibration algorithm was derived without considering the interference effect between the two orthogonally polarized signals merging at a ferrite polarization selector switch. The resulting calibrated brightness temperatures, considered as a function of scan angle, are not symmetric around scan angle = 0. However, neither the origin of the asymmetry nor the manner in which the two orthogonal components are mixed has been fully understood. The new calibration model proposed incorporates all the leakage factors associated with the ferrite switches along the signal paths. The resulting calibration equations clarify how the orthogonal components of surface brightness are coupled at radiometers. As a consequence, the origin of the asymmetry is clearly identified and explained. In addition, the feasibility of absolute calibration using in-orbit data is discussed.

  2. Anastomotic leakage after colorectal surgery: diagnostic accuracy of CT

    Energy Technology Data Exchange (ETDEWEB)

    Kauv, Paul; Benadjaoud, Samir; Boulay-Coletta, Isabelle; Zins, Marc [Fondation Hopital Saint-Joseph, Department of Radiology, Paris (France); Curis, Emmanuel [Universite Paris Descartes, Laboratoire de biomathematiques, Faculte de pharmacie, Paris (France); Loriau, Jerome [Fondation Hopital Saint-Joseph, Department of Digestive Surgery, Paris (France)

    2015-12-15

    To evaluate the diagnostic accuracy of CT in postoperative colorectal anastomotic leakage (AL). Two independent blinded radiologists reviewed 153 CTs performed for suspected AL within 60 days after surgery in 131 consecutive patients, with (n = 58) or without (n = 95) retrograde contrast enema (RCE). Results were compared to original interpretations. The reference standard was reoperation or consensus (a radiologist and a surgeon) regarding clinical, laboratory, radiological, and follow-up data after medical treatment. AL was confirmed in 34/131 patients. For the two reviewers and original interpretation, sensitivity of CT was 82 %, 87 %, and 71 %, respectively; specificity was 84 %, 84 %, and 92 %. RCE significantly increased the positive predictive value (from 40 % to 88 %, P = 0.0009; 41 % to 92 %, P = 0.0016; and 40 % to 100 %, P = 0.0006). Contrast extravasation was the most sensitive (reviewers, 83 % and 83 %) and specific (97 % and 97 %) sign and was significantly associated with AL by univariate analysis (P < 0.0001 and P < 0.0001). By multivariate analysis with recursive partitioning, CT with RCE was accurate to confirm or rule out AL with contrast extravasation. CT with RCE is accurate for diagnosing postoperative colorectal AL. Contrast extravasation is the most reliable sign. RCE should be performed during CT for suspected AL. (orig.)

  3. Rotordynamic and leakage characteristics of a 4-stage brush seal

    Science.gov (United States)

    Conner, K. J.; Childs, D. W.

    1992-12-01

    Experimental results are presented for the direct and cross-coupled stiffness and damping coefficients as well as the leakage performance for a 4-stage brush seal. Variable test parameters include the inlet pressure, pressure ratio, shaft speed, fluid prerotation, and seal spacing. Direct damping is shown to increase with running speed; otherwise, the rotordynamic coefficients are relatively insensitive to changes in the test parameters. Cross-coupled stiffness is generally unchanged by increasing the inlet tangential velocity to the seals, suggesting that the brush seal is not affected by inlet swirl. Direct stiffness is shown to increase with frequency; however, the magnitudes of direct stiffness are always positive. Cross-coupled stiffness increases slightly with frequency; yet not as drastically as direct stiffness. Comparisons of test results for the 4-stage brush seal with an 8-cavity labyrinth showed superior rotordynamics performance for the brush seal; viz., large values for direct stiffness and lower values for the (destabilizing) cross-coupled stiffness coefficient. The damping for brush seals is smaller, but comparable to labyrinth seals. The whirl-frequency ratio is always smaller for the brush seal.

  4. Modeling and analysis of sub-surface leakage current in nano-MOSFET under cutoff regime

    Science.gov (United States)

    Swami, Yashu; Rai, Sanjeev

    2017-02-01

    The high leakage current in nano-meter regimes is becoming a significant portion of power dissipation in nano-MOSFET circuits as threshold voltage, channel length, and gate oxide thickness are scaled down to nano-meter range. Precise leakage current valuation and meticulous modeling of the same at nano-meter technology scale is an increasingly a critical work in designing the low power nano-MOSFET circuits. We present a specific compact model for sub-threshold regime leakage current in bulk driven nano-MOSFETs. The proposed logical model is instigated and executed into the latest updated PTM bulk nano-MOSFET model and is found to be in decent accord with technology-CAD simulation data. This paper also reviews various transistor intrinsic leakage mechanisms for nano-MOSFET exclusively in weak inversion, like drain-induced barricade lowering (DIBL), gate-induced drain leakage (GIDL), gate oxide tunneling (GOT) leakage etc. The root cause of the sub-surface leakage current is mainly due to the nano-scale short channel length causing source-drain coupling even in sub-threshold domain. Consequences leading to carriers triumphing the barricade between the source and drain. The enhanced model effectively considers the following parameter dependence in the account for better-quality value-added results like drain-to-source bias (VDS), gate-to-source bias (VGS), channel length (LG), source/drain junction depth (Xj), bulk doping concentration (NBULK), and operating temperature (Top).

  5. CT evaluation of local leakage of bone cement after percutaneous kyphoplasty and vertebroplasty

    Energy Technology Data Exchange (ETDEWEB)

    Lee, In Jae; Choi, A. Lam; Yie, Mi-Yeon; Yoon, Ji Young; Jeon, Eui Yong; Koh, Sung Hye; Yoon, Dae Young; Lim, Kyung Ja (Dept. of Radiology, Hallym Univ. Sacred Heart Hospital, Seoul (Korea)), e-mail: ijlee2003@medimail.co.kr; Im, Hyoung June (Dept. of Occupational Medicine, Hallym Univ. College of Medicine, Seoul (Korea))

    2010-07-15

    Background: Percutaneous injection of bone cement (acrylic cement) during percutaneous kyphoplasty and vertebroplasty can cause symptomatic or asymptomatic complications due to leakage, extravasation or vascular migration of cement. Purpose: To investigate and to compare the incidence and site of local leakage or complications of bone cement after percutaneous kyphoplasty and vertebroplasty using bone cement. Material and Methods: We retrospectively reviewed 473 cases of percutaneous kyphoplasty or vertebroplasty performed under fluoroscopic guidance. Of the 473 cases, follow-up CT scans that covered the treated bones were available for 83 cases (59 kyphoplasty and 24 vertebroplasty). Results: The rate of local leakage of bone cement was 87.5% (21/24) for percutaneous vertebroplasty and 49.2% (29/59) for kyphoplasty. The most common site of local leakage was perivertebral soft tissue (n=8, 38.1%) for vertebroplasty. The most common site of local leakage was a perivertebral vein (n=7, 24.1%) for kyphoplasty. Two cases of pulmonary cement embolism developed: one case after kyphoplasty and one case after vertebroplasty. Conclusion: Local leakage of bone cement was more common for percutaneous vertebroplasty compared with kyphoplasty (P<0.005). The most common sites of local leakage were perivertebral soft tissue and perivertebral vein.

  6. Leakage diagnostics, sealant longevity, sizing and technology transfer in residential thermal distribution systems

    Energy Technology Data Exchange (ETDEWEB)

    Walker, I.; Sherman, M.; Modera, M.; Siegel, J.

    1998-01-01

    This field study concentrated on measurement of duct leakage to outside the conditioned space because this is most useful in energy calculations. For room by room load/comfort requirements, the total duct leakage (including leaks to conditioned space) is more appropriate, particularly for additional comfort considerations. The objective of this field study is to help to identify major sources of uncertainty and to quantify the trade offs between different test methods. The identification of the areas requiring significant improvement will aid in future development of duct leakage test methods. For example, during the course of this study a new method for correcting house pressure tests to account for the presence of duct leakage in measured envelope leakage was developed. Each of the measurement techniques investigated has resulted from a different set of priorities and hence compromises. Thus each one of them is measuring a different physical quantity, although they all report the same parameter; duct leakage to outside at operating conditions. Given that real houses do not meet all of the simplifying assumptions that must be made to achieve similarity, the same numbers from each test method are not expected. Potentially these differences can be quite large and one of the benefits of field measurement is that the differences in the measurements helps put a realistic bound on how different some of these leakage diagnostics may be.

  7. Evaluation of the effects of enameloplasty and air abrasion on sealant micro-leakage.

    Directory of Open Access Journals (Sweden)

    Aliasghar Soleymani

    2014-12-01

    Full Text Available Micro-leakage, one of the major reasons for recurrent decays, may lead to uncontrollable flow of liquids, pulp inflammation and peri-apical pathology. The purpose of this in vitro study was to evaluate micro-leakage of pit and fissure sealants after using three different pit and fissure preparation techniques: 1 acid etching, 2 fissure enameloplasty and acid etching, and 3 air abrasion and acid etching.Sixty-nine extracted sound molars and premolars were randomly divided into three groups (23 samples in each group. Teeth were prepared using one of three occlusal surface treatments. Then the sealant was applied on the occlusal fissures of all teeth. The teeth were thermocycled and stored in normal saline. All teeth were sealed apically and coated with nail varnish and then were immersed in a 2% solution of methylen blue. Two buccolingual sections were made. The surfaces were scored 0 to 3 for the extent of micro-leakage using a stereomicroscope. Data were analyzed by Kruskal- wallis and Dunn procedure.Enameloplasty and acid etching were significantly different regarding micro-leakage (P= 0.016, but no significant difference in micro-leakage was observed between air abrasion and the other methods.Enameloplasty followed by acid etching produced significantly less micro-leakage than the acid etching technique. Air abrasion acid etching was better than the acid etching technique in reducing micro-leakage too.

  8. In vitro and ex vivo microbial leakage assessment in endodontics: A literature review

    Science.gov (United States)

    Savadkouhi, Sohrab Tour; Bakhtiar, Hengameh; Ardestani, Safoura Emami

    2016-01-01

    The aim of this study was to perform a literature review of published in-vitro and ex-vivo studies, which evaluated microbial leakage in endodontics in the past 10 years. A comprehensive electronic literature search was carried out in PubMed database for English articles published from 2005 to 2016 using the keywords “endodontics,” “in vitro,” “ex vivo,” “microbial leakage,” “microbial penetration,” “saliva,” “Enterococcus faecalis,” “E. faecalis,” “endodontic sealers,” “temporary filling material,” “apical plug,” “mineral trioxide aggregate,” and “MTA.” The keywords were combined using Boolean operators AND/OR. Based on our search strategy, 33 relevant articles were included in the study. There are three main methods for assessment of bacterial microleakage, namely, (A) the dual-chamber leakage model, (B) detection of bacteria using a scanning electron microscope (SEM), and (C) polymerase chain reaction. All bacterial leakage models have some limitations and may yield different results compared to other microleakage evaluation techniques (i.e., dye penetration, fluid filtration, or electrochemical tests). The results of SEM correlated with those of microbial leakage test in most studies. Microbial leakage test using saliva better simulates the clinical setting for assessment of the leakage of single or mixed bacterial species. PMID:28032041

  9. A new on-line leakage current monitoring system of ZnO surge arresters

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Bok-Hee [Research Center for Next-Generation High Voltage and Power Technology, Inha University, 253 Yonghyun-dong, Nam-ku, Incheon 402-751 (Korea, Republic of)]. E-mail: bhlee@inha.ac.kr; Kang, Sung-Man [Research Center for Next-Generation High Voltage and Power Technology, Inha University, 253 Yonghyun-dong, Nam-ku, Incheon 402-751 (Korea, Republic of)

    2005-05-15

    This paper presents a new on-line leakage current monitoring system of zinc oxide (ZnO) surge arresters. To effectively diagnose the deterioration of ZnO surge arresters, a new algorithm and on-line leakage current detection device, which uses the time-delay addition method, for discriminating the resistive and capacitive currents was developed to use in the aging test and durability evaluation for ZnO arrester blocks. A computer-based measurement system of the resistive leakage current, the on-line monitoring device can detect accurately the leakage currents flowing through ZnO surge arresters for power frequency ac applied voltages. The proposed on-line leakage current monitoring device of ZnO surge arresters is more highly sensitive and gives more linear response than the existing devices using the detection method of the third harmonic leakage currents. Therefore, the proposed leakage current monitoring device can be useful for predicting the defects and performance deterioration of ZnO surge arresters in power system applications.

  10. Mitral Valve Replacement with Half-and-Half Technique for Recurrent Mitral Paravalvular Leakage.

    Science.gov (United States)

    Morisaki, Akimasa; Kato, Yasuyuki; Takahashi, Yosuke; Shibata, Toshihiko

    2015-05-01

    Reoperation for paravalvular leakage can cause recurrent paravalvular leakage through severe damage to the mitral annulus. Previously, mitral valve replacement using a half-and-half technique for extensive mitral annular calcification was reported; here, application of the technique to treat recurrent paravalvular leakage is described. A 78-year-old male with three prior mitral valve replacements developed recurrent paravalvular leakage, for which he had undergone his third mitral valve replacement at the age of 69 years. On this occasion, a mechanical valve with circumferential equine pericardial patch reinforcement of the annulus had been used. Five years later, the patient developed hemolytic anemia and congestive heart failure due to recurrent paravalvular leakage. Intraoperatively, broad dehiscence was seen between the prosthetic valve and mitral annulus at two sites, the anterior and posterior commissures, without infection. A fourth mitral valve replacement was performed with a St. Jude Medical valve, using a half-and-half technique. This entailed the use of non-everting mattress sutures on the anterior half of the annulus, and everting mattress sutures on the left atrial wall around the posterior half of the annulus. Extensive annular defects required reinforcement of the posterior mitral annulus with a bovine pericardial patch. Postoperative echocardiography showed no paravalvular leakage. The half-and-half technique may be useful in treating recurrent paravalvular leakage of the mitral valve.

  11. Analyzing a database of residential air leakage in the United States

    Science.gov (United States)

    Chan, Wanyu R.; Nazaroff, William W.; Price, Phillip N.; Sohn, Michael D.; Gadgil, Ashok J.

    We analyzed more than 70,000 air leakage measurements in houses across the United States to relate leakage area—the effective size of all penetrations of the building shell—to readily available building characteristics such as building size, year built, geographic region, and various construction characteristics. After adjusting for the lack of statistical representativeness of the data, we found that the distribution of leakage area normalized by floor area is approximately lognormal. Based on a classification tree analysis, year built and floor area are the two most significant predictors of leakage area: older and smaller houses tend to have higher normalized leakage areas than newer and larger ones. Multivariate regressions of normalized leakage are presented with respect to these two factors for three house classifications: low-income households, energy program houses, and conventional houses. We demonstrate a method of applying the regression model to housing characteristics from the American Housing Survey to derive a leakage-area distribution for all single-family houses in the US. The air exchange rates implied by these estimates agree reasonably well with published measurements.

  12. Postprocedural CT for perivertebral cement leakage in percutaneous vertebroplasty is not necessary - results from VERTOS II

    Energy Technology Data Exchange (ETDEWEB)

    Venmans, Alexander; Klazen, Caroline A.; Rooij, Willem Jan van; Lohle, Paul N. [St. Elisabeth Ziekenhuis Tilburg, Department of Radiology, Tilburg (Netherlands); Vries, Jolanda de [St. Elisabeth Ziekenhuis Tilburg, Department of Medical Psychology, Tilburg (Netherlands); Mali, Willem P. [University Medical Centre Utrecht, Department of Radiology, Utrecht (Netherlands)

    2011-01-15

    During percutaneous vertebroplasty (PV), perivertebral cement leakage frequently occurs. There is some concern that cement deposits may migrate towards the lungs via the veins during follow-up. We used baseline and follow-up computed tomography (CT) to assess the incidence and extend of late cement migration in a large consecutive patient cohort. VERTOS II is a prospective multicenter randomized controlled trial comparing PV with conservative therapy for osteoporotic vertebral compression fractures (OVCFs). Patients assigned to PV had baseline postprocedural CT scans of the treated vertebral bodies. After a mean follow-up of 22 months, 54 of 78 patients (69%) had follow-up CT. CT scans were analyzed and compared for perivertebral venous, discal, and soft tissue leakage. Perivertebral cement leakage occurred in 64 of 80 treated vertebrae (80%; 95% CI, 70% to 87%). All patients remained asymptomatic. Perivertebral venous leakage was present in 56 vertebrae (88%), mostly in the anterior external venous plexus (46 of 56, 82%). Discal leakage occurred in 22 of 64 vertebrae (34%) and soft tissue leakage in two of 64 (4%). Mean injected cement volume in vertebrae with leakage was higher (4.5 versus 3.7 cm{sup 3}, p = 0.04). Follow-up CT scan showed unchanged perivertebral cement leakages without late cement migration. Perivertebral cement leaks during PV for OVCFs occurred frequently in the VERTOS II trial. Cement leakage occurred more frequently with higher injected volumes. However, all patients remained asymptomatic, and late cement migration during follow-up did not occur. Standard postprocedural CT of the treated vertebral body in PV is not necessary. (orig.)

  13. A retrospective analysis of endoscopic treatment outcomes in patients with postoperative bile leakage

    Science.gov (United States)

    Sayar, Suleyman; Olmez, Sehmus; Avcioglu, Ufuk; Tenlik, Ilyas; Saritas, Bunyamin; Ozdil, Kamil; Altiparmak, Emin; Ozaslan, Ersan

    2016-01-01

    OBJECTIVE: Bile leakage, while rare, can be a complication seen after cholecystectomy. It may also occur after hepatic or biliary surgical procedures. Etiology may be underlying pathology or surgical complication. Endoscopic retrograde cholangiopancreatography (ERCP) can play major role in diagnosis and treatment of bile leakage. Present study was a retrospective analysis of outcomes of ERCP procedure in patients with bile leakage. METHODS: Patients who underwent ERCP for bile leakage after surgery between 2008 and 2012 were included in the study. Etiology, clinical and radiological characteristics, and endoscopic treatment outcomes were recorded and analyzed. RESULTS: Total of 31 patients (10 male, 21 female) were included in the study. ERCP was performed for bile leakage after cholecystectomy in 20 patients, after hydatid cyst operation in 10 patients, and after hepatic resection in 1 patient. Clinical signs and symptoms of bile leakage included abdominal pain, bile drainage from percutaneous drain, peritonitis, jaundice, and bilioma. Twelve (60%) patients were treated with endoscopic sphincterotomy (ES) and nasobiliary drainage (NBD) catheter, 7 patients (35%) were treated with ES and biliary stent (BS), and 1 patient (5%) was treated with ES alone. Treatment efficiency was 100% in bile leakage cases after cholecystectomy. Ten (32%) cases of hydatid cyst surgery had subsequent cystobiliary fistula. Of these patients, 7 were treated with ES and NBD, 2 were treated with ES and BS, and 1 patient (8%) with ES alone. Treatment was successful in 90% of these cases. CONCLUSION: ERCP is an effective method to diagnose and treat bile leakage. Endoscopic treatment of postoperative bile leakage should be individualized based on etiological and other factors, such as accompanying fistula. PMID:28058396

  14. Quantification of marginal leakage area of aesthetic restorations systems used in indirect inlays

    Directory of Open Access Journals (Sweden)

    Gleidson Rocha Arouca

    2011-01-01

    Full Text Available Introduction and objective: Marginal leakage of inlays restorations is a key issue for dentists, because of the damaging consequences that its intensity may cause to the tooth, periodontium, and longevity of restoration. The aim of this study was to assess the cervical marginal leakage of two composite systems and a pressed ceramic, through area calculation associated with the longest distance between the restoration and preparation cervical edges. Material and methods: Based on a metal pattern model with MOD inlay preparation, 15 type IV dental stone casts were obtained and randomly distributed into three groups (n = 5 as follows: Empress Group, Sinfony Group, Z350 Group. After restorations had been made, each one was positioned on the pattern model. Following, their middle and distal faces were photographed in order to analyze marginal cervical leakage through a computer software program. Results: Cervical marginal leakage area: there was statistically significant difference among the three groups (P < 0.05. Empress Group presented the highest values, followed by Sinfony and Z350 groups. Empress and Sinfony groups showed, respectively, a leakage area of 280% and 110% higher than Z350 group. Longest distance between restoration and preparation edges: Statistically significant differences were not observed between Empress and Sinfony groups; however, they showed statistically significant (P < 0.05 differences when compared to Z350 group (215% and 120% greater leakage than Z350 group, respectively. Conclusion: Considering the cervical marginal leakage area calculation and the longest distance between restoration and preparation edges, marginal leakage was smaller in Z350 group followed by Sinfony and Empress groups. In the analysis of cervical marginal leakage, all groups were clinically acceptable.

  15. Dosimetry and evaluating the effect of treatment parameters on the leakage of multi leaf collimators in ONCOR linear accelerators

    Directory of Open Access Journals (Sweden)

    Keyvan Jabbari

    2016-01-01

    Conclusions: The amount of leakage was more for 18 MV compare to 6 MV The percentage of the leakage for both energies is less than the 5% value which is recommended by protocols. The fluctuation of the MLC leakage reduced by increasing the field size and depth.

  16. Efficient quantum dialogue using entangled states and entanglement swapping without information leakage

    Science.gov (United States)

    Wang, He; Zhang, Yu Qing; Liu, Xue Feng; Hu, Yu Pu

    2016-06-01

    We propose a novel quantum dialogue protocol by using the generalized Bell states and entanglement swapping. In the protocol, a sequence of ordered two-qutrit entangled states acts as quantum information channel for exchanging secret messages directly and simultaneously. Besides, a secret key string is shared between the communicants to overcome information leakage. Different from those previous information leakage-resistant quantum dialogue protocols, the particles, composed of one of each pair of entangled states, are transmitted only one time in the proposed protocol. Security analysis shows that our protocol can overcome information leakage and resist several well-known attacks. Moreover, the efficiency of our scheme is acceptable.

  17. Cumulative Impacts of Energy and Climate Change Policies on Carbon Leakage

    Energy Technology Data Exchange (ETDEWEB)

    Varma, A.; Milnes, R.; Miller, K.; Williams, E. [AEA Technology plc, London (United Kingdom); De Bruyn, S.; Brinke, L. [CE Delft, Delft (Netherlands)

    2012-02-15

    Carbon leakage occurs when climate change policy aimed at reducing carbon dioxide emissions in one country leads to an increase in carbon dioxide emissions in a country that is not bound by these policies. Given that climate change is a global issue, carbon leakage impacts upon the effectiveness of climate change policies. This independent study examines the cumulative impact of climate change policies on carbon leakage. The report brings together findings and analysis from a wide range of primary literature in this area and where possible, conclusions relevant to the UK are drawn.

  18. ERROR REDUCTION IN DUCT LEAKAGE TESTING THROUGH DATA CROSS-CHECKS

    Energy Technology Data Exchange (ETDEWEB)

    ANDREWS, J.W.

    1998-12-31

    One way to reduce uncertainty in scientific measurement is to devise a protocol in which more quantities are measured than are absolutely required, so that the result is over constrained. This report develops a method for so combining data from two different tests for air leakage in residential duct systems. An algorithm, which depends on the uncertainty estimates for the measured quantities, optimizes the use of the excess data. In many cases it can significantly reduce the error bar on at least one of the two measured duct leakage rates (supply or return), and it provides a rational method of reconciling any conflicting results from the two leakage tests.

  19. A Review of Novel Leakage Current Suppression Techniques for Transformerless Photovoltaic Inverters

    Institute of Scientific and Technical Information of China (English)

    WU Weiyang; GUO Xiaoqiang

    2012-01-01

    In recent years, the transformerless PV inverters have been paid more attention due to cost and size reduction, as well as efficiency improvement compared with the conventional transformer ones. Leakage current suppression is one of the most important techniques for transformerless grid connected photovoltaic systems. The objective of this paper is to present a comprehensive review of the recently developed solution to the leakage current reduction. First of all, the common-mode model of the PV system is described to explain how the leakage current generates.

  20. Connexin26 regulates assembly and maintenance of cochlear gap junction macromolecular complex for normal hearing

    Science.gov (United States)

    Kamiya, Kazusaku; Fukunaga, Ichiro; Hatakeyama, Kaori; Ikeda, Katsuhisa

    2015-12-01

    Hereditary deafness affects about 1 in 2000 children and GJB2 gene mutation is most frequent cause for this disease in the world. GJB2 encodes connexin26 (Cx26), a component in cochlear gap junction. Recently, we found macromolecular change of gap junction plaques with two different types of Cx26 mutation as major classification of clinical case, one is a model of dominant negative type, Cx26R75W+ and the other is conditional gene deficient mouse, Cx26f/fP0Cre as a model for insufficiency of gap junction protein [6]. Gap junction composed mainly of Cx26 and Cx30 in wild type mice formed large planar gap junction plaques (GJP). In contrast, Cx26R75W+ and Cx26f/fP0Cre showed fragmented small round GJPs around the cell border. In Cx26f/fP0Cre, some of the cells with Cx26 expression due to their cellular mosaicism showed normal large GJP with Cx26 and Cx30 only at the cell junction site between two Cx26 positive cells. These indicate that bilateral Cx26 expressions from both adjacent cells are essential for the formation of the cochlear linear GJP, and it is not compensated by other cochlear Connexins such as Connexin30. In the present study, we demonstrated a new molecular pathology in most common hereditary deafness with different types of Connexin26 mutations, and this machinery can be a new target for drag design of hereditary deafness.

  1. Temperature Sensitivity as a Microbial Trait Using Parameters from Macromolecular Rate Theory

    Directory of Open Access Journals (Sweden)

    Charlotte Jean Alster

    2016-11-01

    Full Text Available The activity of soil microbial extracellular enzymes is strongly controlled by temperature, yet the degree to which temperature sensitivity varies by microbe and enzyme type is unclear. Such information would allow soil microbial enzymes to be incorporated in a traits-based framework to improve prediction of ecosystem response to global change. If temperature sensitivity varies for specific soil enzymes, then determining the underlying causes of variation in temperature sensitivity of these enzymes will provide fundamental insights for predicting nutrient dynamics belowground. In this study, we characterized how both microbial taxonomic variation as well as substrate type affects temperature sensitivity. We measured β-glucosidase, leucine aminopeptidase, and phosphatase activities at six temperatures: 4, 11, 25, 35, 45, and 60°C, for seven different soil microbial isolates. To calculate temperature sensitivity, we employed two models, Arrhenius, which predicts an exponential increase in reaction rate with temperature, and Macromolecular Rate Theory (MMRT, which predicts rate to peak and then decline as temperature increases. We found MMRT provided a more accurate fit and allowed for more nuanced interpretation of temperature sensitivity in all of the enzyme × isolate combinations tested. Our results revealed that both the enzyme type and soil isolate type explain variation in parameters associated with temperature sensitivity. Because we found temperature sensitivity to be an inherent and variable property of an enzyme, we argue that it can be incorporated as a microbial functional trait, but only when using the MMRT definition of temperature sensitivity. We show that the Arrhenius metrics of temperature sensitivity are overly sensitive to test conditions, with activation energy changing depending on the temperature range it was calculated within. Thus, we propose the use of the MMRT definition of temperature sensitivity for accurate

  2. Temperature Sensitivity as a Microbial Trait Using Parameters from Macromolecular Rate Theory.

    Science.gov (United States)

    Alster, Charlotte J; Baas, Peter; Wallenstein, Matthew D; Johnson, Nels G; von Fischer, Joseph C

    2016-01-01

    The activity of soil microbial extracellular enzymes is strongly controlled by temperature, yet the degree to which temperature sensitivity varies by microbe and enzyme type is unclear. Such information would allow soil microbial enzymes to be incorporated in a traits-based framework to improve prediction of ecosystem response to global change. If temperature sensitivity varies for specific soil enzymes, then determining the underlying causes of variation in temperature sensitivity of these enzymes will provide fundamental insights for predicting nutrient dynamics belowground. In this study, we characterized how both microbial taxonomic variation as well as substrate type affects temperature sensitivity. We measured β-glucosidase, leucine aminopeptidase, and phosphatase activities at six temperatures: 4, 11, 25, 35, 45, and 60°C, for seven different soil microbial isolates. To calculate temperature sensitivity, we employed two models, Arrhenius, which predicts an exponential increase in reaction rate with temperature, and Macromolecular Rate Theory (MMRT), which predicts rate to peak and then decline as temperature increases. We found MMRT provided a more accurate fit and allowed for more nuanced interpretation of temperature sensitivity in all of the enzyme × isolate combinations tested. Our results revealed that both the enzyme type and soil isolate type explain variation in parameters associated with temperature sensitivity. Because we found temperature sensitivity to be an inherent and variable property of an enzyme, we argue that it can be incorporated as a microbial functional trait, but only when using the MMRT definition of temperature sensitivity. We show that the Arrhenius metrics of temperature sensitivity are overly sensitive to test conditions, with activation energy changing depending on the temperature range it was calculated within. Thus, we propose the use of the MMRT definition of temperature sensitivity for accurate interpretation of

  3. The High Mosaicity Illusion: Revealing the True Physical Characteristics of Macromolecular Crystals

    Science.gov (United States)

    Bellamy, Henry; Snell, Edward H.; Borgstahl, Gloria

    2000-01-01

    An experimental system and software have been developed for simultaneously measuring the diffraction resolution and mosaic spread of macromolecular crystals. Hundreds of reflection profiles over a wide resolution range were rapidly measured by using a charge coupled device (CCD) area detector in combination with superfine phi slicing data collection. The contributions of the X-ray beam to the reflection widths were minimized by using a highly-parallel, highly-monochromatic synchrotron source. These contributions and Lorentz effects were evaluated and deconvoluted from the recorded data. Data collection and processing is described. From one degree of superfine phi slice data collected on a crystal of manganese superoxide dismutase the mosaicity of 261 reflections were measured. The average mosaicity was 0.0101 degrees (0.0035) at the full-width-at-half-maximum (FWHM) and ranged from 0.0011 degrees to 0.0188 degrees. Each reflection profile was individually fit with two gaussian profiles with the first gaussian contributing 55% and the second contributing 35% of the reflection. On average, the mosaicity of the first gaussian was 0.0054 degrees (0.0015) and the second was 0.0061 degrees (0.0023). The mosaicity of the crystal was anisotropic with fh, f k, and fl values of 0.0068 degrees, 0.0140 degrees and 0.0046 degrees, respectively at the FWHM. The anisotropic mosaicity analysis indicates that the crystal is the most perfect in the I direction which corresponds to the favored growth direction of the crystal.

  4. Facilities for macromolecular crystallography at the Helmholtz-Zentrum Berlin.

    Science.gov (United States)

    Mueller, Uwe; Darowski, Nora; Fuchs, Martin R; Förster, Ronald; Hellmig, Michael; Paithankar, Karthik S; Pühringer, Sandra; Steffien, Michael; Zocher, Georg; Weiss, Manfred S

    2012-05-01

    Three macromolecular crystallography (MX) beamlines at the Helmholtz-Zentrum Berlin (HZB) are available for the regional, national and international structural biology user community. The state-of-the-art synchrotron beamlines for MX BL14.1, BL14.2 and BL14.3 are located within the low-β section of the BESSY II electron storage ring. All beamlines are fed from a superconducting 7 T wavelength-shifter insertion device. BL14.1 and BL14.2 are energy tunable in the range 5-16 keV, while BL14.3 is a fixed-energy side station operated at 13.8 keV. All three beamlines are equipped with CCD detectors. BL14.1 and BL14.2 are in regular user operation providing about 200 beam days per year and about 600 user shifts to approximately 50 research groups across Europe. BL14.3 has initially been used as a test facility and was brought into regular user mode operation during the year 2010. BL14.1 has recently been upgraded with a microdiffractometer including a mini-κ goniometer and an automated sample changer. Additional user facilities include office space adjacent to the beamlines, a sample preparation laboratory, a biology laboratory (safety level 1) and high-end computing resources. In this article the instrumentation of the beamlines is described, and a summary of the experimental possibilities of the beamlines and the provided ancillary equipment for the user community is given.

  5. Role of solvent properties of aqueous media in macromolecular crowding effects.

    Science.gov (United States)

    Ferreira, Luisa A; Madeira, Pedro P; Breydo, Leonid; Reichardt, Christian; Uversky, Vladimir N; Zaslavsky, Boris Y

    2016-01-01

    Analysis of the macromolecular crowding effects in polymer solutions show that the excluded volume effect is not the only factor affecting the behavior of biomolecules in a crowded environment. The observed inconsistencies are commonly explained by the so-called soft interactions, such as electrostatic, hydrophobic, and van der Waals interactions, between the crowding agent and the protein, in addition to the hard nonspecific steric interactions. We suggest that the changes in the solvent properties of aqueous media induced by the crowding agents may be the root of these "soft" interactions. To check this hypothesis, the solvatochromic comparison method was used to determine the solvent dipolarity/polarizability, hydrogen-bond donor acidity, and hydrogen-bond acceptor basicity of aqueous solutions of different polymers (dextran, poly(ethylene glycol), Ficoll, Ucon, and polyvinylpyrrolidone) with the polymer concentration up to 40% typically used as crowding agents. Polymer-induced changes in these features were found to be polymer type and concentration specific, and, in case of polyethylene glycol (PEG), molecular mass specific. Similarly sized polymers PEG and Ucon producing different changes in the solvent properties of water in their solutions induced morphologically different α-synuclein aggregates. It is shown that the crowding effects of some polymers on protein refolding and stability reported in the literature can be quantitatively described in terms of the established solvent features of the media in these polymers solutions. These results indicate that the crowding agents do induce changes in solvent properties of aqueous media in crowded environment. Therefore, these changes should be taken into account for crowding effect analysis.

  6. Structure of metaphase chromosomes: a role for effects of macromolecular crowding.

    Directory of Open Access Journals (Sweden)

    Ronald Hancock

    Full Text Available In metaphase chromosomes, chromatin is compacted to a concentration of several hundred mg/ml by mechanisms which remain elusive. Effects mediated by the ionic environment are considered most frequently because mono- and di-valent cations cause polynucleosome chains to form compact ~30-nm diameter fibres in vitro, but this conformation is not detected in chromosomes in situ. A further unconsidered factor is predicted to influence the compaction of chromosomes, namely the forces which arise from crowding by macromolecules in the surrounding cytoplasm whose measured concentration is 100-200 mg/ml. To mimic these conditions, chromosomes were released from mitotic CHO cells in solutions containing an inert volume-occupying macromolecule (8 kDa polyethylene glycol, 10.5 kDa dextran, or 70 kDa Ficoll in 100 µM K-Hepes buffer, with contaminating cations at only low micromolar concentrations. Optical and electron microscopy showed that these chromosomes conserved their characteristic structure and compaction, and their volume varied inversely with the concentration of a crowding macromolecule. They showed a canonical nucleosomal structure and contained the characteristic proteins topoisomerase IIα and the condensin subunit SMC2. These observations, together with evidence that the cytoplasm is crowded in vivo, suggest that macromolecular crowding effects should be considered a significant and perhaps major factor in compacting chromosomes. This model may explain why ~30-nm fibres characteristic of cation-mediated compaction are not seen in chromosomes in situ. Considering that crowding by cytoplasmic macromolecules maintains the compaction of bacterial chromosomes and has been proposed to form the liquid crystalline chromosomes of dinoflagellates, a crowded environment may be an essential characteristic of all genomes.

  7. Prospects for simulating macromolecular surfactant chemistry at the ocean-atmosphere boundary

    Science.gov (United States)

    Elliott, S.; Burrows, S. M.; Deal, C.; Liu, X.; Long, M.; Ogunro, O.; Russell, L. M.; Wingenter, O.

    2014-05-01

    Biogenic lipids and polymers are surveyed for their ability to adsorb at the water-air interfaces associated with bubbles, marine microlayers and particles in the overlying boundary layer. Representative ocean biogeochemical regimes are defined in order to estimate local concentrations for the major macromolecular classes. Surfactant equilibria and maximum excess are then derived based on a network of model compounds. Relative local coverage and upward mass transport follow directly, and specific chemical structures can be placed into regional rank order. Lipids and denatured protein-like polymers dominate at the selected locations. The assigned monolayer phase states are variable, whether assessed along bubbles or at the atmospheric spray droplet perimeter. Since oceanic film compositions prove to be irregular, effects on gas and organic transfer are expected to exhibit geographic dependence as well. Moreover, the core arguments extend across the sea-air interface into aerosol-cloud systems. Fundamental nascent chemical properties including mass to carbon ratio and density depend strongly on the geochemical state of source waters. High surface pressures may suppress the Kelvin effect, and marine organic hygroscopicities are almost entirely unconstrained. While bubble adsorption provides a well-known means for transporting lipidic or proteinaceous material into sea spray, the same cannot be said of polysaccharides. Carbohydrates tend to be strongly hydrophilic so that their excess carbon mass is low despite stacked polymeric geometries. Since sugars are abundant in the marine aerosol, gel-based mechanisms may be required to achieve uplift. Uncertainties distill to a global scale dearth of information regarding two dimensional kinetics and equilibria. Nonetheless simulations are recommended, to initiate the process of systems level quantification.

  8. Prospects for Simulating Macromolecular Surfactant Chemistry at the Ocean-Atmosphere Boundary

    Energy Technology Data Exchange (ETDEWEB)

    Elliott, S.; Burrows, Susannah M.; Deal, C.; Liu, Xiaohong; Long, M.; Ogunro, O.; Russell, Lynn M.; Wingenter, O.

    2014-05-01

    Biogenic lipids and polymers are surveyed for their ability to adsorb at the water-air interfaces associated with bubbles, marine microlayers and particles in the overlying boundary layer. Representative ocean biogeochemical regimes are defined in order to estimate local concentrations for the major macromolecular classes. Surfactant equilibria and maximum excess are then derived based on a network of model compounds. Relative local coverage and upward mass transport follow directly, and specific chemical structures can be placed into regional rank order. Lipids and denatured protein-like polymers dominate at the selected locations. The assigned monolayer phase states are variable, whether assessed along bubbles or at the atmospheric spray droplet perimeter. Since oceanic film compositions prove to be irregular, effects on gas and organic transfer are expected to exhibit geographic dependence as well. Moreover, the core arguments extend across the sea-air interface into aerosol-cloud systems. Fundamental nascent chemical properties including mass to carbon ratio and density depend strongly on the geochemical state of source waters. High surface pressures may suppress the Kelvin effect, and marine organic hygroscopicities are almost entirely unconstrained. While bubble adsorption provides a well-known means for transporting lipidic or proteinaceous material into sea spray, the same cannot be said of polysaccharides. Carbohydrates tend to be strongly hydrophilic so that their excess carbon mass is low despite stacked polymeric geometries. Since sugars are abundant in the marine aerosol, gel-based mechanisms may be required to achieve uplift. Uncertainties in the surfactant logic distill to a global scale dearth of information regarding two dimensional kinetics and equilibria. Nonetheless simulations are recommended, to initiate the process of systems level quantification.

  9. Structure of metaphase chromosomes: a role for effects of macromolecular crowding.

    Science.gov (United States)

    Hancock, Ronald

    2012-01-01

    In metaphase chromosomes, chromatin is compacted to a concentration of several hundred mg/ml by mechanisms which remain elusive. Effects mediated by the ionic environment are considered most frequently because mono- and di-valent cations cause polynucleosome chains to form compact ~30-nm diameter fibres in vitro, but this conformation is not detected in chromosomes in situ. A further unconsidered factor is predicted to influence the compaction of chromosomes, namely the forces which arise from crowding by macromolecules in the surrounding cytoplasm whose measured concentration is 100-200 mg/ml. To mimic these conditions, chromosomes were released from mitotic CHO cells in solutions containing an inert volume-occupying macromolecule (8 kDa polyethylene glycol, 10.5 kDa dextran, or 70 kDa Ficoll) in 100 µM K-Hepes buffer, with contaminating cations at only low micromolar concentrations. Optical and electron microscopy showed that these chromosomes conserved their characteristic structure and compaction, and their volume varied inversely with the concentration of a crowding macromolecule. They showed a canonical nucleosomal structure and contained the characteristic proteins topoisomerase IIα and the condensin subunit SMC2. These observations, together with evidence that the cytoplasm is crowded in vivo, suggest that macromolecular crowding effects should be considered a significant and perhaps major factor in compacting chromosomes. This model may explain why ~30-nm fibres characteristic of cation-mediated compaction are not seen in chromosomes in situ. Considering that crowding by cytoplasmic macromolecules maintains the compaction of bacterial chromosomes and has been proposed to form the liquid crystalline chromosomes of dinoflagellates, a crowded environment may be an essential characteristic of all genomes.

  10. Development of an online UV-visible microspectrophotometer for a macromolecular crystallography beamline.

    Science.gov (United States)

    Shimizu, Nobutaka; Shimizu, Tetsuya; Baba, Seiki; Hasegawa, Kazuya; Yamamoto, Masaki; Kumasaka, Takashi

    2013-11-01

    Measurement of the UV-visible absorption spectrum is a convenient technique for detecting chemical changes of proteins, and it is therefore useful to combine spectroscopy and diffraction studies. An online microspectrophotometer for the UV-visible region was developed and installed on the macromolecular crystallography beamline, BL38B1, at SPring-8. This spectrophotometer is equipped with a difference dispersive double monochromator, a mercury-xenon lamp as the light source, and a photomultiplier as the detector. The optical path is mostly constructed using mirrors, in order to obtain high brightness in the UV region, and the confocal optics are assembled using a cross-slit diaphragm like an iris to eliminate stray light. This system can measure optical densities up to a maximum of 4.0. To study the effect of radiation damage, preliminary measurements of glucose isomerase and thaumatin crystals were conducted in the UV region. Spectral changes dependent on X-ray dose were observed at around 280 nm, suggesting that structural changes involving Trp or Tyr residues occurred in the protein crystal. In the case of the thaumatin crystal, a broad peak around 400 nm was also generated after X-ray irradiation, suggesting the cleavage of a disulfide bond. Dose-dependent spectral changes were also observed in cryo-solutions alone, and these changes differed with the composition of the cryo-solution. These responses in the UV region are informative regarding the state of the sample; consequently, this device might be useful for X-ray crystallography.

  11. Isolation and characterization of macromolecular protein R-Phycoerythrin from Portieria hornemannii.

    Science.gov (United States)

    Senthilkumar, Namasivayam; Suresh, Veeraperumal; Thangam, Ramar; Kurinjimalar, Chidambaram; Kavitha, Ganapathy; Murugan, Pitchai; Kannan, Soundarapandian; Rengasamy, Ramasamy

    2013-04-01

    R-Phycoerythrin (R-PE) is one of the three phycobiliproteins which are extensively used as fluorescent probes, and it is prepared from red macro-algae. This macromolecular protein has gained importance in many biotechnological applications in food science, immunodiagnostic, therapy, cosmetics, protein and cell labeling, and analytical processes. In the present investigation, R-PE was isolated and purified from a red alga Portieria hornemannii. R-PE extracted and purified through ammonium sulfate precipitation (55%) followed by Q-Sepharose column chromatography had yielded a maximum purity of 5.2%. R-PE exhibited a typical "three-peak" with absorption maxima at 499, 545 and 565 nm. CD spectrum of R-PE yielded the following secondary structure data: alpha helix (14.30%), beta helix (28.10%), turn helix (19.20%) and random coil helix (38.40%). The molecular mass of R-PE was 240 kDa under Native-PAGE. Three different subunits such as α, β and γ of 16 kDa, 21 kDa and 39 kDa were segregated under SDS-PAGE. On two dimensional gel electrophoresis, one basic and four acidic subunits were detected. Five different tryptic peptides were assigned under MALDI-TOF. The sequences of N-terminus of R-PE of 10 different amino acids are Met Lys Gln Met Trp Asp Arg Met Val Val. The preparative procedures of the R-PE extraction and purification established based on the experiments exhibit advantages and can offer a reference for R-PE preparation from other marine red macro-alga P. hornemannii.

  12. Room-temperature macromolecular crystallography using a micro-patterned silicon chip with minimal background scattering

    Science.gov (United States)

    Roedig, Philip; Duman, Ramona; Sanchez-Weatherby, Juan; Vartiainen, Ismo; Burkhardt, Anja; Warmer, Martin; David, Christian; Wagner, Armin; Meents, Alke

    2016-01-01

    Recent success at X-ray free-electron lasers has led to serial crystallography experiments staging a comeback at synchrotron sources as well. With crystal lifetimes typically in the millisecond range and the latest-generation detector technologies with high framing rates up to 1 kHz, fast sample exchange has become the bottleneck for such experiments. A micro-patterned chip has been developed from single-crystalline silicon, which acts as a sample holder for up to several thousand microcrystals at a very low background level. The crystals can be easily loaded onto the chip and excess mother liquor can be efficiently removed. Dehydration of the crystals is prevented by keeping them in a stream of humidified air during data collection. Further sealing of the sample holder, for example with Kapton, is not required. Room-temperature data collection from insulin crystals loaded onto the chip proves the applicability of the chip for macromolecular crystallography. Subsequent structure refinements reveal no radiation-damage-induced structural changes for insulin crystals up to a dose of 565.6 kGy, even though the total diffraction power of the crystals has on average decreased to 19.1% of its initial value for the same dose. A decay of the diffracting power by half is observed for a dose of D 1/2 = 147.5 ± 19.1 kGy, which is about 1/300 of the dose before crystals show a similar decay at cryogenic temperatures. PMID:27275143

  13. Bubble counter based on photoelectric technique for leakage detection of cryogenic valves

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    In order to overcome the inconvenience of manual bubble counting, a bubble counter based on photoelectric technique aiming for automatically detecting and measuring minute gas leakage of cryogenic valves is proposed. Experiments have been conducted on a self-built apparatus, testing the performance with different gas inlet strategies (bottom gas-inlet strategy and side gas-inlet strategy) and the influence of gas pipe length (0, 1, 2, 4, 6, 8, 10 m) and leakage rate (around 10, 20, 30, 40 bubbles/min) on first bubble time and bubble rate. A buffer of 110 cm3 is inserted between leakage source and gas pipe to simulate the downstream cavum adjacent to the valve clack. Based on analyzing the experimental data, experiential parameters have also been summarized to guide leakage detection and measurement for engineering applications. A practical system has already been successfully applied in a cryogenic testing apparatus for cryogenic valves.

  14. Compilation of current literature on seals, closures, and leakage for radioactive material packagings

    Energy Technology Data Exchange (ETDEWEB)

    Warrant, M.M.; Ottinger, C.A.

    1989-01-01

    This report presents an overview of the features that affect the sealing capability of radioactive material packagings currently certified by the US Nuclear Regulatory Commission. The report is based on a review of current literature on seals, closures, and leakage for radioactive material packagings. Federal regulations that relate to the sealing capability of radioactive material packagings, as well as basic equations for leakage calculations and some of the available leakage test procedures are presented. The factors which affect the sealing capability of a closure, including the properties of the sealing surfaces, the gasket material, the closure method and the contents are discussed in qualitative terms. Information on the general properties of both elastomer and metal gasket materials and some specific designs are presented. A summary of the seal material, closure method, and leakage tests for currently certified packagings with large diameter seals is provided. 18 figs., 9 tabs.

  15. The Tip Leakage Flow Structure of an Axial Fan with Tip Clearance

    Institute of Scientific and Technical Information of China (English)

    竺晓程; 杜朝辉; 林万来

    2003-01-01

    Experiment and numerical simulation technique are used to investigate the tip leakage flow in an axial fanwith tip clearance at the design condition. The flow field in the tip region of fan is measured using a PDA (ParticleDynamics Analysis) system. The flow is surveyed across the whole passage at fifteen axial locations (from the100% axial chord in front of the leading edge to the 100% axial chord behind the trailing edge), mainly focusing onthe outer 90% blade span. Both experiment measurement and numerical simulation indicates the leakage flow orig-inated from the tip clearance along the chord rolls-up into three-dimensional spiral structure to form leakage flowvortex. The interaction of leakage flow and main flow will produce the low velocity zone, and block the flow. Theleakage flow almost occupies the most part of flow passage behind the trailing edge.

  16. Peritoneal microdialysis. Early diagnosis of anastomotic leakage after low anterior resection for rectosigmoid cancer

    DEFF Research Database (Denmark)

    Pedersen, Mark Ellebæk; Qvist, N; Bisgaard, C;

    2009-01-01

    BACKGROUND: The aim of the present study was to evaluate the efficacy and safety of intraperitoneal microdialysis in early detection of anastomotic leakage after low anterior resection for rectosigmoid cancer. METHODS: In a series of 116 consecutive patients scheduled for low anterior resection......-252) hours. Samples were collected every 4-hours, and the concentration of glucose, lactate, pyruvate and glycerol was measured. RESULTS: Four patients developed symptomatic anastomotic leakage. Two patients developed non-abdominal sepsis. In 38 patients the postoperative course was uncomplicated...... anastomotic leakage it coincided with the development of clinical symptoms. In the two patients with non-abdominal sepsis the values were within normal range. CONCLUSION: Peritoneal microdialysis is a safe and promising tool in early diagnosis of anastomotic leakage after low anterior resection...

  17. A Modified Time-Delay Addition Method to Extract Resistive Leakage Current of MOSA

    Science.gov (United States)

    Khodsuz, Masume; Mirzaie, Mohammad

    2016-12-01

    Metal oxide surge arresters are one of the most important equipment for power system protection against switching and lightning over-voltages. High-energy stresses and environmental features are the main factors which degrade surge arresters. In order to verify surge arresters good condition, their monitoring is necessary. The majority of surge arrester monitoring techniques is based on total leakage current decomposition of their capacitive and resistive components. This paper introduces a new approach based on time-delay addition method to extract the resistive current from the total leakage current without measuring voltage signal. Surge arrester model for calculating leakage current has been performed in ATP-EMTP. In addition, the signal processing has been done using MATLAB software. To show the accuracy of the proposed method, experimental tests have been performed to extract resistive leakage current by the proposed method.

  18. Sub-Threshold Leakage Current Reduction Techniques In VLSI Circuits -A Survey

    Directory of Open Access Journals (Sweden)

    V.Sri Sai Harsha

    2015-09-01

    Full Text Available There is an increasing demand for portable devices powered up by battery, this led the manufacturers of semiconductor technology to scale down the feature size which results in reduction in threshold voltage and enables the complex functionality on a single chip. By scaling down the feature size the dynamic power dissipation has no effect but the static power dissipation has become equal or more than that of Dynamic power dissipation. So in recent CMOS technologies static power dissipation i.e. power dissipation due to leakage current has become a challenging area for VLSI chip designers. In order to prolong the battery life and maintain reliability of circuit, leakage current reduction is the primary goal. A basic overview of techniques used for reduction of sub-threshold leakages is discussed in this paper. Based on the surveyed techniques, one would be able to choose required and apt leakage reduction technique.

  19. A Study on the EM Leakage Arising from Braided Shielding Cable

    Institute of Scientific and Technical Information of China (English)

    ZHANG Hong-xin; L(U) Ying-hua; BAO Yong-fang; L(U) Jian-gang

    2005-01-01

    To investigate the electromagnetic leakage caused by braided shielding cable, the finite-difference formulation of braided shielding cable for both the inner shield-conductor circuit and outer shield-ground circuit are proposed. Then, the current in shield-ground circuit induced by the transmitting signal in the cable is computed in time-domain, and the shielding effectiveness of braided shield against trapezoid signals is studied. Further more, the video EM leakage in far zone is calculated. At last, the information leakage caused by EM radiation of braided cable is intercepted and recovered using the simulation platform. It is proved that EM radiation of braided cable can give rise to information leakage. It is a key factor that should be concerned in the information secure field.

  20. Increased risk of anastomotic leakage with diclofenac treatment after laparoscopic colorectal surgery

    DEFF Research Database (Denmark)

    Klein, Mads; Andersen, Lars Peter Holst; Harvald, Thomas

    2009-01-01

    BACKGROUND: Over a period our department experienced an unexpected high frequency of anastomotic leakages. After diclofenac was removed from the postoperative analgesic regimen, the frequency dropped. This study aimed to evaluate the influence of diclofenac on the risk of developing anastomotic...... leakage after laparoscopic colorectal surgery. METHODS: This was a retrospective case-control study based on 75 consecutive patients undergoing laparoscopic colorectal resection with primary anastomosis. In period 1, patients received diclofenac 150 mg/day. In period 2, diclofenac was withdrawn...... and the patients received an opioid analgesic instead. The primary outcome parameter was clinically significant anastomotical leakage verified at reoperation. RESULTS: 1/42 patients in the no-diclofenac group compared with 7/33 in the diclofenac group had an anastomotic leakage after operation (p = 0...

  1. The Study of Magnetic Flux Shunts Effects on the Leakage Reactance of Transformers via FEM

    Directory of Open Access Journals (Sweden)

    Karim Abbaszadeh

    2010-09-01

    Full Text Available The influence of arrangement, dimensions, and magnetic permeability of the magnetic flux shunts on the flux distribution and leakage reactance of the power transformers is studied in this paper by using a finite elements method and a simple modeling approach. By using magneto-static analysis and finite element method, first the flux distribution in the 2D model of a core-type three phase power transformer and then using the magnetic stored energy method the leakage reactance of the transformer windings is calculated. By studying the different models including magnetic flux shunts, the effect of the arrangement, geometric dimensions as well as the magnetic permeability of the magnetic flux shunt on the leakage reactance of the transformer are studied and some interesting results are obtained. It is shown that the variation of these parameters in the transformer model has significant effects on the leakage reactance of the transformer.

  2. RF leakage current in electrosurgical units: Influence of the layout in taking measurements

    Science.gov (United States)

    Gentile, L.; Palacios, P.

    2007-11-01

    The RF leakage current in electrosurgical units is a critical parameter to measure, because it may cause accidental burns in patients. The particular standard for electrosurgical units IEC 60601-2-2 indicates the maximum RF leakage levels and defines the elements and their layout to do these measurements. On this paper we show the RF leakage current values of 6 electrosurgical units. We did these measurements in two different ways: in the first one we measured in normal conditions of use in the operating rooms and in the second we followed the mentioned Standard. The results shows differences between one group and the other, observing higher RF leakage current values in the measurements that we did without following the standard's layout.

  3. RF leakage current in electrosurgical units: Influence of the layout in taking measurements

    Energy Technology Data Exchange (ETDEWEB)

    Gentile, L; Palacios, P [Cardiology and Cardiovascular Surgery Institute, Favaloro Foundation Biomedical Engineering Department, Av. Belgrano 1746. Bs. As. (Argentina)

    2007-11-15

    The RF leakage current in electrosurgical units is a critical parameter to measure, because it may cause accidental burns in patients. The particular standard for electrosurgical units IEC 60601-2-2 indicates the maximum RF leakage levels and defines the elements and their layout to do these measurements. On this paper we show the RF leakage current values of 6 electrosurgical units. We did these measurements in two different ways: in the first one we measured in normal conditions of use in the operating rooms and in the second we followed the mentioned Standard. The results shows differences between one group and the other, observing higher RF leakage current values in the measurements that we did without following the standard's layout.

  4. The Analysis and Comparison of Leakage Inductance in Different Winding Arrangements for Planar Transformer

    DEFF Research Database (Denmark)

    Ouyang, Ziwei; Thomsen, Ole Cornelius; Andersen, Michael Andreas E.

    2009-01-01

    (MMF) and energy distribution in planar transformer and correct the formula of leakage inductance proposed by previous publications. The investigation of different winding arrangements shows significant advantages of interleaving structure. In this work, a novel half turn structure is proposed...

  5. A method to investigate inter-aquifer leakage using hydraulics and multiple environmental tracers

    Science.gov (United States)

    Priestley, Stacey; Love, Andrew; Wohling, Daniel; Post, Vincent; Shand, Paul; Kipfer, Rolf; Tyroller, Lina

    2016-04-01

    Informed aquifer management decisions regarding sustainable yields or potential exploitation require an understanding of the groundwater system (Alley et al. 2002, Cherry and Parker 2004). Recently, the increase in coal seam gas (CSG) or shale gas production has highlighted the need for a better understanding of inter-aquifer leakage and contaminant migration. In most groundwater systems, the quantity or location of inter-aquifer leakage is unknown. Not taking into account leakage rates in the analysis of large scale flow systems can also lead to significant errors in the estimates of groundwater flow rates in aquifers (Love et al. 1993, Toth 2009). There is an urgent need for robust methods to investigate inter-aquifer leakage at a regional scale. This study builds on previous groundwater flow and inter-aquifer leakage studies to provide a methodology to investigate inter-aquifer leakage in a regional sedimentary basin using hydraulics and a multi-tracer approach. The methodology incorporates geological, hydrogeological and hydrochemical information in the basin to determine the likelihood and location of inter-aquifer leakage. Of particular benefit is the analysis of hydraulic heads and environmental tracers at nested piezometers, or where these are unavailable bore couplets comprising bores above and below the aquitard of interest within a localised geographical area. The proposed methodology has been successful in investigating inter-aquifer leakage in the Arckaringa Basin, South Australia. The suite of environmental tracers and isotopes used to analyse inter-aquifer leakage included the stable isotopes of water, radiocarbon, chloride-36, 87Sr/86Sr and helium isotopes. There is evidence for inter-aquifer leakage in the centre of the basin ~40 km along the regional flow path. This inter-aquifer leakage has been identified by a slight draw-down in the upper aquifer during pumping in the lower aquifer, overlap in Sr isotopes, δ2H, δ18O and chloride

  6. Perturbation-based Markovian transmission model for probing allosteric dynamics of large macromolecular assembling: a study of GroEL-GroES.

    Directory of Open Access Journals (Sweden)

    Hsiao-Mei Lu

    2009-10-01

    Full Text Available Large macromolecular assemblies are often important for biological processes in cells. Allosteric communications between different parts of these molecular machines play critical roles in cellular signaling. Although studies of the topology and fluctuation dynamics of coarse-grained residue networks can yield important insights, they do not provide characterization of the time-dependent dynamic behavior of these macromolecular assemblies. Here we develop a novel approach called Perturbation-based Markovian Transmission (PMT model to study globally the dynamic responses of the macromolecular assemblies. By monitoring simultaneous responses of all residues (>8,000 across many (>6 decades of time spanning from the initial perturbation until reaching equilibrium using a Krylov subspace projection method, we show that this approach can yield rich information. With criteria based on quantitative measurements of relaxation half-time, flow amplitude change, and oscillation dynamics, this approach can identify pivot residues that are important for macromolecular movement, messenger residues that are key to signal mediating, and anchor residues important for binding interactions. Based on a detailed analysis of the GroEL-GroES chaperone system, we found that our predictions have an accuracy of 71-84% judged by independent experimental studies reported in the literature. This approach is general and can be applied to other large macromolecular machineries such as the virus capsid and ribosomal complex.

  7. Aging changes of macromolecular synthesis in the digestive organs of mice as revealed by microscopic radioautography and X-ray microanalysis

    Energy Technology Data Exchange (ETDEWEB)

    Nagata, Tetsuji [Shinshu Univ., Matsumoto (Japan). School of Medicine. Dept. of Anatomy and Cell Biology]. E-mail: nagatas@po.cnet.ne.jp

    2002-07-01

    For the purpose of elucidating the aging changes of macromolecular synthesis such as DNA, RNA, proteins, glycoproteins, glycides and lipids in various organ systems of experimental animals, we have studied the digestive organs of aging mice and rats as a series of systematic studies using light and electron microscopic radioautography after incorporations with macromolecular precursors. The experimental animals mainly used were ddY strain mice at various aging groups from embryo to postnatal days 1 and 3, weeks 1 and 2, months 1, 2, 6, 12 up to 2 year senescent stages as well as several groups of adult Wistar rats. The animals were injected with such macromolecular precursors as {sup 3}H - thymidine for DNA, {sup 3}H-uridine for RNA, {sup 3}H-leucine and {sup 3}H proline for proteins, {sup 35}SO{sub 4} for glycoproteins, {sup 3} H-glucosamine for glucides and {sup 3}H-glycerol for lipids. The results demonstrated that these precursors were incorporated into various cell types in the oral cavity, the salivary glands, the esophagus, the stomach, the small and large intestines, the liver and the pancreas at various ages from perinatal to juvenile, mature and senescent stages, showing specific patterns of macromolecular synthesis. It is concluded that these specific patterns of macromolecular synthesis in respective cell types demonstrated the organ specificity of aging of animals. (author)

  8. Distributed temperature monitoring for liquid sodium leakage detection using OFDR-based Rayleigh backscattering

    Science.gov (United States)

    Boldyreva, E.; Cotillard, R.; Laffont, G.; Ferdinand, P.; Cambet, D.; Jeannot, J.-P.; Charvet, P.; Albaladéjo, S.; Rodriguez, G.

    2014-05-01

    For the first time, a gold coated single mode optical fiber has been used to detect a liquid sodium leakage on a pipe of secondary circuit pipe mock-up of nuclear fast reactor (Gen IV) by means of Optical Frequency Domain Reflectometry-based on Rayleigh backscattering. During 150 min of the experiment we were able to detect and monitor the evolution of a liquid sodium leakage on the surface of the pipe.

  9. Leakage Characteristics of Dual-Cannula Fenestrated Tracheostomy Tubes during Positive Pressure Ventilation: A Bench Study

    OpenAIRE

    Thomas Berlet; Mathias Marchon

    2016-01-01

    This study compared the leakage characteristics of different types of dual-cannula fenestrated tracheostomy tubes during positive pressure ventilation. Fenestrated Portex® Blue Line Ultra®, TRACOE® twist, or Rüsch® Traceofix® tracheostomy tubes equipped with nonfenestrated inner cannulas were tested in a tracheostomy-lung simulator. Transfenestration pressures and transfenestration leakage rates were measured during positive pressure ventilation. The impact of different ventilation modes, air...

  10. Subarachnoid Hemorrhage Presenting with Seizure due to Cerebrospinal Fluid Leakage after Spinal Surgery.

    Science.gov (United States)

    Bozkurt, Gokhan; Yaman, Mesut Emre

    2016-01-01

    Cerebrospinal fluid leakage may commonly occur during spinal surgeries and it may cause dural tears. These tears may result in hemorrhage in the entire compartments of the brain. Most common site of such hemorrhages are the veins in the cerebellar region. We report a case of hemorrhage, mimicking aneurysmal subarachnoid hemorrhage due to a cerebrospinal fluid leakage following lumbar spinal surgery and discuss the possible mechanisms of action.

  11. Intrathoracic anastomotic leakage after gastroesophageal cancer resection is associated with increased risk of recurrence

    DEFF Research Database (Denmark)

    Kofoed, Steen C; Calatayud, Dan; Jensen, Lone S

    2015-01-01

    OBJECTIVE: Intrathoracic anastomotic leakage after intended curative resection for cancer in the esophagus or gastroesophageal junction has a negative impact on long-term survival. The aim of this study was to investigate whether an anastomotic leakage was associated with an increased recurrence......]: 1.17-2.29, P = .004) and all-cause mortality (HR = 1.57; 95% CI: 1.23-2.05, P cancer resection....

  12. Design of Low Power CMOS Circuits using Leakage Control Transistor and Multi-Threshold CMOS Techniques

    OpenAIRE

    2012-01-01

    The scaling down of technology in CMOS circuits, results in the down scaling of threshold voltage thereby increasing the sub-threshold leakage current. An IC consists of many circuits of which some circuits consists critical path like full adder, whereas some circuits like multiplexer and decoder has no specified critical path. LECTOR is a technique for designing leakage power reduced CMOS circuits without affecting the dynamic power dissipation, which can be used for circuits with no specifi...

  13. Leakage Risk Assessment for a Potential CO2 Storage Project in Saskatchewan, Canada

    Energy Technology Data Exchange (ETDEWEB)

    Houseworth, J.E.; Oldenburg, C.M.; Mazzoldi, A.; Gupta, A.K.; Nicot, J.-P.; Bryant, S.L.

    2011-05-01

    A CO{sub 2} sequestration project is being considered to (1) capture CO{sub 2} emissions from the Consumers Cooperative Refineries Limited at Regina, Saskatchewan and (2) geologically sequester the captured CO{sub 2} locally in a deep saline aquifer. This project is a collaboration of several industrial and governmental organizations, including the Petroleum Technology Research Centre (PTRC), Sustainable Development Technology Canada (SDTC), SaskEnvironment Go Green Fund, SaskPower, CCRL, Schlumberger Carbon Services, and Enbridge. The project objective is to sequester 600 tonnes CO{sub 2}/day. Injection is planned to start in 2012 or 2013 for a period of 25 years for a total storage of approximately 5.5 million tonnes CO{sub 2}. This report presents an assessment of the leakage risk of the proposed project using a methodology known as the Certification Framework (CF). The CF is used for evaluating CO{sub 2} leakage risk associated with geologic carbon sequestration (GCS), as well as brine leakage risk owing to displacement and pressurization of brine by the injected CO{sub 2}. We follow the CF methodology by defining the entities (so-called Compartments) that could be impacted by CO{sub 2} leakage, the CO{sub 2} storage region, the potential for leakage along well and fault pathways, and the consequences of such leakage. An understanding of the likelihood and consequences of leakage forms the basis for understanding CO{sub 2} leakage risk, and forms the basis for recommendations of additional data collection and analysis to increase confidence in the risk assessment.

  14. Advanced Detection Technology of Trace-level Borate for SG Leakage Monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Seban; Kang, Dukwon; Kim, Seungil; Kim, Hyunki; Heo, Jun; Sung, Jinhyun [Radiation Eng. Center, Shihung (Korea, Republic of); Lee, Dongbum [Academic Support Dept., Seoul (Korea, Republic of)

    2013-05-15

    Many studies have been reported for monitoring technology of steam generator, however, all of these methods have their own limitations. The leakage monitoring technology of steam generator of PWR has also got a limit due to the adoption of specific radionuclides (N-16, Ar-41, H-3, Xe, etc.) generated by nuclear fission, which are available only when reactor output is 20% or more. Most of domestic NPPs apply the N-16 technique for monitoring tube leakage but it has some problem that it is difficult to calculate the leakage rate because neutron flux are not completely formed during low power operation. For example, tube leakage of steam generator occurred in the Uljin nuclear power plant in 2002 during coast down operation for periodic plant maintenance. This plant could not prevent a rupture accident in advance because N-16 method is not possible the leak monitoring less than 20% reactor power. The development of excellent alternative monitoring technology that can monitor the real-time leakage is required under a variety of operating conditions like start-up and abnormal conditions of NPPs. This study was performed to lay a foundation in monitoring the leakage of steam generator coping with the lower output and low power operational condition using trace level of boron which is non-radioactive nuclide to inject control neutron injection. In this study, non-radioactive nuclide boron ion, which existed in the secondary system water, as leakage monitoring indicator was investigated for the separation of complex cation and anion phase. Borate was detected by using borate concentrator column coupled with the ion-exclusion column analytical column, revealing the problem of overlapped peak between fluoride and boron ions. Meanwhile, ion-exchange column could confirm the possibility as a leakage monitoring indicator of steam generator, despite the peak of glycolic acid salts was slightly overlapped. It will be needed for further research regarding the selectivity of the

  15. Potential for the Use of Wireless Sensor Networks for Monitoring of CO2 Leakage Risks

    Science.gov (United States)

    Pawar, R.; Illangasekare, T. H.; Han, Q.; Jayasumana, A.

    2015-12-01

    Storage of supercritical CO2 in deep saline geologic formation is under study as a means to mitigate potential global climate change from green house gas loading to the atmosphere. Leakage of CO2 from these formations poses risk to the storage permanence goal of 99% of injected CO2 remaining sequestered from the atmosphere,. Leaked CO2 that migrates into overlying groundwater aquifers may cause changes in groundwater quality that pose risks to environmental and human health. For these reasons, technologies for monitoring, measuring and accounting of injected CO2 are necessary for permitting of CO2 sequestration projects under EPA's class VI CO2 injection well regulations. While the probability of leakage related to CO2 injection is thought to be small at characterized and permitted sites, it is still very important to protect the groundwater resources and develop methods that can efficiently and accurately detect CO2 leakage. Methods that have been proposed for leakage detection include remote sensing, soil gas monitoring, geophysical techniques, pressure monitoring, vegetation stress and eddy covariance measurements. We have demonstrated the use of wireless sensor networks (WSN) for monitoring of subsurface contaminant plumes. The adaptability of this technology for leakage monitoring of CO2 through geochemical changes in the shallow subsurface is explored. For this technology to be viable, it is necessary to identify geochemical indicators such as pH or electrical conductivity that have high potential for significant change in groundwater in the event of CO2 leakage. This talk presents a conceptual approach to use WSNs for CO2 leakage monitoring. Based on our past work on the use of WSN for subsurface monitoring, some of the challenges that need to be over come for this technology to be viable for leakage detection will be discussed.

  16. CO2 Leakage, Storage and Injection Monitoring by Using Experimental, Numerical and Analytical Methods

    Directory of Open Access Journals (Sweden)

    A. Namdar

    2014-09-01

    Full Text Available The maintaining environment is priority to any plan in human life. It is planned for monitoring CO2 injection, storage and leakage by using geophysical, numerical and analytical methods in seismic zone. In this regard the mineralogy, chemical composite, lithology, seismic wave propagation, small earthquake, accelerating natural earthquake, thermal stress-strain modeling, ground movement level and fault activation will be consider. It is expected to better understand CO2 leakage, storage and injection process and problems.

  17. Effect of lymph leakage on renal allograft outcome from living donors

    Directory of Open Access Journals (Sweden)

    Abolfazl Bohlouli

    2012-01-01

    Full Text Available Lymph leakage is a cause of prolonged fluid discharge in renal transplant patients. Lymph leakage during early post-transplantation is responsible for extracting immune substances; therefore, it may play a role in prognosis of the transplanted kidney. In this study, we aimed to investigate the effects of lymph leakage on different factors that play significant roles in renal allograft outcome. During the present case-control study, we evaluated 62 renal allograft recipients in which 31 subjects were complicated with lymph leakage and enrolled as the study group. The other 31 subjects were included in the control group who did not experience any lymph leakage during their post-transplantation period. All kidneys were transplanted from living donors. We investigated and compared the renal allograft rejection rate, hospitalization duration, serum urea, creatinine (Cr and cyclosporine (CsA levels, antithymoglobin (ATG administration and treatment duration between the study and the control groups. There were no significant difference in the urea and Cr levels between the two groups (P >0.05. Early (one week and late (one month serum CsA levels of the study group were significantly higher than in the control group (P = 0.005 and P = 0.006. The number of days in which ATG receivers responded to therapy was significantly lower for the control group (P = 0.008. 21.93% of the study group subjects experienced allograft rejection, while this rejection probability was 28.38% for the control group (P = 0.799. Lymph leakage has no prominent role in renal function, which is estimated by Cr and urea levels in patients′ serum during the days after transplantation. CsA level was higher in patients with lymph leakage, and all cases of allograft rejection were in the subjects with lymph leakage.

  18. β-Cyclodextrin-Based Inclusion Complexation Bridged Biodegradable Self-Assembly Macromolecular Micelle for the Delivery of Paclitaxel.

    Directory of Open Access Journals (Sweden)

    Yanzuo Chen

    Full Text Available In this study, a novel adamantanamine-paclitaxel (AD-PTX incorporated oligochitosan- carboxymethyl-β-cyclodextrin (CSO-g-CM-β-CD self-assembly macromolecular (CSO-g-CM-β-CD@AD-PTX micelle was successfully prepared in water through sonication. The formed molecules were characterized by Fourier transform infrared spectroscopy, proton nuclear magnetic resonance (NMR spectroscopy, two-dimensional NMR, elemental analysis, and liquid chromatography-mass spectrometry, while the correspondent micelles were characterized by dynamic light scattering and transmission electron microscopy. We showed that the macromolecular micelle contained a spherical core-shell structure with a diameter of 197.1 ± 3.3 nm and zeta potential of -19.1 ± 4.3 mV. The CSO-g-CM-β-CD@AD-PTX micelle exhibited a high drug-loading efficacy up to 31.3%, as well as a critical micelle concentration of 3.4 × 10-7 M, which indicated good stability. Additionally, the in vitro release profile of the CSO-g-CM-β-CD@AD-PTX micelle demonstrated a long-term release pattern, 63.1% of AD-PTX was released from the micelle during a 30-day period. Moreover, the CSO-g-CM-β-CD@AD-PTX micelle displayed cytotoxicity at a sub-μM scale similar to PTX in U87 MG cells, and CSO-g-CM-β-CD exhibited a good safety profile by not manifesting significant toxicity at concentrations up to 100 μM. These results indicated that β-CD-based inclusion complexation resulting in biodegradable self-assembled macromolecular micelles can be utilized as nanocarrier, and may provide a promising platform for drug delivery in the future medical applications.

  19. Investigation on the influence of leakage clearance on the flow field and performance of scroll hydraulic pump

    Science.gov (United States)

    Sun, Shuaihui; Huang, Yi; Guo, Pengcheng; Zuo, Juanli; Luo, Xingqi

    2016-11-01

    In the present paper, the computer fluid dynamics(CFD) with dynamic mesh model had been applied in scroll hydraulic pump to obtain its flow field at different leakage clearance. The fluid force on the orbiting scroll, the mass flow rate and the hydraulic efficiency at different leakage clearance were calculated based on the flow field data. The results indicated that when the leakage clearance increased from 0.5mm to 1.5mm, the average pressure, maximum of pressure fluctuation, leakage jet flow velocity, shaft power, cavitation degree decreased and the leakage flow rate increased. If the leakage clearance was 2.0mm, the high pressure discharge fluid flowed through the clearance and led to the increase of the average pressure and fluid force. When the leakage clearance is 1.0mm, the average pressure is far lower than that at the 0.5mm clearance, and the hydraulic efficiency is the highest.

  20. MX1: a bending-magnet crystallography beamline serving both chemical and macromolecular crystallography communities at the Australian Synchrotron.

    Science.gov (United States)

    Cowieson, Nathan Philip; Aragao, David; Clift, Mark; Ericsson, Daniel J; Gee, Christine; Harrop, Stephen J; Mudie, Nathan; Panjikar, Santosh; Price, Jason R; Riboldi-Tunnicliffe, Alan; Williamson, Rachel; Caradoc-Davies, Tom

    2015-01-01

    MX1 is a bending-magnet crystallography beamline at the 3 GeV Australian Synchrotron. The beamline delivers hard X-rays in the energy range from 8 to 18 keV to a focal spot at the sample position of 120 µm FWHM. The beamline endstation and ancillary equipment facilitate local and remote access for both chemical and biological macromolecular crystallography. Here, the design of the beamline and endstation are discussed. The beamline has enjoyed a full user program for the last seven years and scientific highlights from the user program are also presented.

  1. Nitrogen limitation in natural populations of cyanobacteria (Spirulina and Oscillatoria spp. ) and its effect on macromolecular synthesis

    Energy Technology Data Exchange (ETDEWEB)

    van Rijn, J.; Shilo, M.

    1986-08-01

    Natural populations of the cyanobacteria Spirulina species and Oscillatoria species obtained from Israeli fish ponds were limited in growth by nitrogen availability in summer. Physiological indicators for nitrogen limitation, such as phycocyanin, chlorophyll a, and carbohydrate content, did not show clear evidence for nitrogen limited growth, since these organisms are capable of vertical migration from and to the nitrogen-rich bottom. By means of /sup 14/C labeling of the cells under simulated pond conditions followed by cell fractionation into macromolecular compounds, it was found that carbohydrates synthesized at the lighted surface were partially utilized for dark protein synthesis at the bottom of these ponds.

  2. Holographic methods in X-ray crystallography. Pt. 4. A fast algorithm and its application to macromolecular crystallography

    Energy Technology Data Exchange (ETDEWEB)

    Somoza, J.R. [California Univ., Berkeley (United States). Dept. of Chemistry]|[Lawrence Berkeley Lab., CA (United States); Szoeke, H. [Lawrence Livermore National Lab., CA (United States); Goodman, D.M. [Lawrence Livermore National Lab., CA (United States); Beran, P. [Lawrence Livermore National Lab., CA (United States); Truckses, D. [Wisconsin Univ., Madison, WI (United States). Dept. of Biochemistry; Kim, S.H. [California Univ., Berkeley (United States). Dept. of Chemistry]|[Lawrence Berkeley Lab., CA (United States); Szoeke, A. [Lawrence Livermore National Lab., CA (United States)

    1995-09-01

    The holographic method makes use of partially modeled electron density and experimentally measured structure-factor amplitudes to recover electron density corresponding to the unmodeled part of a crystal structure. This paper describes a fast algorithm that makes it possible to apply the holographic method to sizable crystallographic problems. The algorithm uses positivity constraints on the electron density and can incorporate a `target` electron density, making it similar to solvent flattening. The potential for applying the holographic method to macromolecular X-ray crystallography is assessed using both synthetic and experimental data. (orig.).

  3. Comparison of two self-assembled macromolecular prodrug micelles with different conjugate positions of SN38 for enhancing antitumor activity

    Directory of Open Access Journals (Sweden)

    Liu Y

    2015-03-01

    Full Text Available Yi Liu,1 Hongyu Piao,1 Ying Gao,1 Caihong Xu,2 Ye Tian,1 Lihong Wang,1 Jinwen Liu,1 Bo Tang,1 Meijuan Zou,1 Gang Cheng1 1Department of Pharmaceutics, Shenyang Pharmaceutical University, Shenyang, Liaoning Province, People’s Republic of China; 2Department of Food Science, Shenyang Normal University, Shenyang, Liaoning Province, People’s Republic of China Abstract: 7-Ethyl-10-hydroxycamptothecin (SN38, an active metabolite of irinotecan (CPT-11, is a remarkably potent antitumor agent. The clinical application of SN38 has been extremely restricted by its insolubility in water. In this study, we successfully synthesized two macromolecular prodrugs of SN38 with different conjugate positions (chitosan-(C10-OHSN38 and chitosan-(C20-OHSN38 to improve the water solubility and antitumor activity of SN38. These prodrugs can self-assemble into micelles in aqueous medium. The particle size, morphology, zeta potential, and in vitro drug release of SN38 and its derivatives, as well as their cytotoxicity, pharmacokinetics, and in vivo antitumor activity in a xenograft BALB/c mouse model were studied. In vitro, chitosan-(C10-OHSN38 (CS-(10sSN38 and chitosan-(C20-OHSN38 (CS-(20sSN38 were 13.3- and 25.9-fold more potent than CPT-11 in the murine colon adenocarcinoma cell line CT26, respectively. The area under the curve (AUC0–24 of SN38 after intravenously administering CS-(10sSN38 and CS-(20sSN38 to Sprague Dawley rats was greatly improved when compared with CPT-11 (both P<0.01. A larger AUC0–24 of CS-(20sSN38 was observed when compared to CS-(10sSN38 (P<0.05. Both of the novel self-assembled chitosan-SN38 prodrugs demonstrated superior anticancer activity to CPT-11 in the CT26 xenograft BALB/c mouse model. We have also investigated the differences between these macromolecular prodrug micelles with regards to enhancing the antitumor activity of SN38. CS-(20sSN38 exhibited better in vivo antitumor activity than CS-(10sSN38 at a dose of 2.5 mg/kg (P<0

  4. Assessment Of Carbon Leakage In Multiple Carbon-Sink Projects: ACase Study In Jambi Province, Indonesia

    Energy Technology Data Exchange (ETDEWEB)

    Boer, Rizaldi; Wasrin, Upik R.; Hendri, Perdinan; Dasanto,Bambang D.; Makundi, Willy; Hero, Julius; Ridwan, M.; Masripatin, Nur

    2007-06-01

    Rehabilitation of degraded forest land throughimplementation of carbon sink projects can increase terrestrial carbonstock. However, carbon emissions outside the project boundary, which iscommonly referred to as leakage, may reduce or negate the sequestrationbenefits. This study assessed leakage from carbon sink projects thatcould potentially be implemented in the study area comprised of elevensub-districts in the Batanghari District, Jambi Province, Sumatra,Indonesia. The study estimates the probability of a given land use/coverbeing converted into other uses/cover, by applying a logit model. Thepredictor variables were: proximity to the center of the land use area,distance to transportation channel (road or river), area of agriculturalland, unemployment (number of job seekers), job opportunities, populationdensity and income. Leakage was estimated by analyzing with and withoutcarbon sink projects scenarios. Most of the predictors were estimated asbeing significant in their contribution to land use cover change. Theresults of the analysis show that leakage in the study area can be largeenough to more than offset the project's carbon sequestration benefitsduring the period 2002-2012. However, leakage results are very sensitiveto changes of carbon density of the land uses in the study area. Byreducing C-density of lowland and hill forest by about 10 percent for thebaseline scenario, the leakage becomes positive. Further data collectionand refinement is therefore required. Nevertheless, this study hasdemonstrated that regional analysis is a useful approach to assessleakage.

  5. Space Shuttle Orbital Maneuvering Subsystem (OMS) Engine Propellant Leakage Ball-Valve Shaft Seals

    Science.gov (United States)

    Lueders, Kathy; Buntain, Nick; Fries, Joseph (Technical Monitor)

    1999-01-01

    Evidence of propellant leakage across ball-valve shaft seals has been noted during the disassembly of five flight engines and one test engine at the NASA Lyndon B. Johnson Space Center, White Sands Test Facility. Based on data collected during the disassembly of these five engines, the consequences of propellant leakage across the ball-valve shaft seals can be divided into four primary areas of concern: Damage to the ball-valve pinion shafts, damage to sleeved bearings inside the ball-valve and actuator assemblies, degradation of the synthetic rubber o-rings used in the actuator assemblies, and corrosion and degradation to the interior of the actuator assemblies. The exact time at which leakage across the ball-valve shaft seals occurs has not been determined, however, the leakage most likely occurs during engine firings when, depending on the specification used, ball-valve cavity pressures range as high as 453 to 550 psia. This potential pressure range for the ball-valve cavities greatly exceeds the acceptance leakage test pressure of 332 psia. Since redesign and replacement of the ball-valve shaft seals is unlikely, the near term solution to prevent damage that occurs from shaft-seal leakage is to implement a routine overhaul and maintenance program for engines in the fleet. Recommended repair, verification, and possible preventative maintenance measures are discussed in the paper.

  6. Investigating the effects of the interface defects on the gate leakage current in MOSFETs

    Science.gov (United States)

    Mao, Ling-Feng

    2008-08-01

    The effects of the interface defects on the gate leakage current have been numerically modeled. The results demonstrate that the shallow and deep traps have different effects on the dependence relation of the stress-induced leakage current on the oxide electric field in the regime of direct tunneling, whereas both traps keep the same dependence relation in the regime of Fowler-Nordheim tunneling. The results also shows that the stress-induced leakage current will be the largest at a moderate oxide voltage for the electron interface traps but it increases with the decreasing oxide voltage for the hole interface traps. The results illustrate that the stress-induced leakage current strongly depends on the location of the electron interface traps but it weakly depends on the location of the hole interface traps. The increase in the gate leakage current caused by the electron interface traps can predict the increase, then decrease in the stress-induced leakage current, with decreasing oxide thickness, which is observed experimentally. And the electron interface trap level will have a large effect on the peak height and position.

  7. Evaluation of marginal leakage of different temporary restorative materials in Endodontics

    Directory of Open Access Journals (Sweden)

    Pedro Henrique Duarte França de Castro

    2013-01-01

    Full Text Available Aim: The aim of this study is to assess the coronal marginal leakage of three temporary restorative materials used for root canal sealing after endodontic treatment. Materials and Methods: A total of 88 single-rooted teeth were submitted to biomechanical preparation and filled by lateral condensation technique. After obturation process, the teeth were randomly separated into four groups, being two teeth of each group used as positive and negative control. Temporary sealing was performed as follows: GI - Clip F (VOCO; GII - Bioplic (Biodinβmica; GIII - Vitremer (3M ESPE and GIV - Ketak N100 (3M ESPE. Next, the specimens were immersed into Indian ink for 30 and 60- days, being 10 specimens for each time interval and then submitted to diaphanization to verify the amount of coronal leakage using a measuring microscope. Results : Leakage mean values within the 30-day period were as follows: Vitremer (0.3 mm, Ketak N100 and Clip F (0.6 mm and Bioplic (1.7 mm. Within the 60-day period, leakage means were 1.1 mm, 1.5 mm, 2.2 mm and 2.6 mm, respectively. Conclusions: None of the materials was capable of preventing marginal leakage within the 30- and 60-day period. In both time intervals, Bioplic presented the highest mean of leakage and Vitremer the lowest.

  8. Research of Temperature Tracer Method to Detect Tubular Leakage Passage in Earth-Dam

    Institute of Scientific and Technical Information of China (English)

    WANG Xin-jian; CHEN Jian-sheng

    2006-01-01

    The location, intensity and scope of concentrated leakage must be determined in order to repair earth-Dam scoured by the leakage. In this paper, firstly, heat tracer theory and distribution laws of temperature in soil body with leakage are discussed. Then temperature tracer model is established according to stable heat conduction theory. In such model, the concentrated seepage passage is simplified into a circular pipe as a boundary condition. The location, scope and flow-velocity of the concentrated leakage are estimated via ichnography of the lowest temperature based on temperature data from detecting wells by quantitative computation and qualitative analysis. In case study, the distribution characteristic of temperature (including temperature data of water in reservoir, drainage pipes and tail pond) can be interpreted by this model. A modified model is also set up, applied for detected data at different cross-sections of the leakage passage, in which the temperature data are rectified according to distances from data locations to calculating section. Finally, the model is solved by numerical iterative method, and the possible error of this theoretical model is discussed. The permeability coefficient in leakage area is identical with that of normal soil in magnitude after anti-seepage repairing accomplished, which indicates this model is effective.

  9. Analysis of mine's air leakage based on pressure gradient matrix between nodes

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jian-rang; WANG Hong-gang; WU Feng-liang; CHANG Xin-tan

    2008-01-01

    Air leakage may significantly affect the effectiveness of mine ventilation by in-creasing the cost of ventilation and arousing problems for ventilation management. Fur-thermore, air leakage may accelerate the process of coal spontaneous combustion andcause gas explosion, thus greatly threatens the safety of coat production. The estimationof air leakage, therefore, have great practical significance. For any ventilation system ofcoal mines, there is a defined pattern of pressure gradient which drived the mine air toflow in the network, drives possible air leakage to go shortcut as well. Air leakage mayoccur through ventilation structures such as ventilation doors and fractures of the surroun-dig coal and rock of airways. A concept and the relevent calculation method of the pres-sure gradient matrix was put forward to assist the analysis of potential air leakage routes.A simplified example was used to introduce the application principle of'pressure gradientmatrix in identifying all the potential air leaking routes, which offers a deeper understand-ing over the ventilation system and the prevention of coal spontaneous combustion.

  10. COMPUTATIONAL AND EXPERIMENTAL STUDY ON TIP LEAKAGE VORTEX OF CIRCUMFERENTIAL SKEWED BLADES

    Institute of Scientific and Technical Information of China (English)

    LI Yang; OUYANG Hua; DU Zhaohui

    2007-01-01

    In the steady operation condition, the experiments and the numerical simulations are used to investigate the tip leakage flow fields in three low pressure axial flow fans with three kinds of circumferential skewed rotors, including the radial rotor, the forward-skewed rotor and the backward-skewed rotor. The three-dimensional viscous flow fields of the fans are computed. In the experiments, the two-dimensional plane particle image velocimetry (PIV) system is used to measure the flow fields in the tip region of three different pitchwise positions of each fan. The results show that the computational results agree well with the experimental data in the flow field of the tip region of each fan. The tip leakage vortex core segments based on method of the eigenmode analysis can display clearly some characteristics of the tip leakage vortex, such as the origination position of tip leakage vortex, the development of vortex strength, and so on. Compared with the radial rotor, the other two skewed rotors can increase the stability of the tip leakage vortex and the increment in the forward-skewed rotor is more than that in the backward-skewed one. Among the tip leakage vortices of the three rotors, the velocity of the vortex in the forward-skewed rotor is the highest in the circumferential direction and the lowest in the axial direction.

  11. Long-term monitoring of marine gas leakage

    Science.gov (United States)

    Spickenbom, Kai; Faber, Eckhard; Poggenburg, Jürgen; Seeger, Christian; Furche, Markus

    2010-05-01

    The sequestration of CO2 in sub-seabed geological formations is one of the Carbon Capture and Storage (CCS) strategies currently under study. Although offshore operations are significantly more expensive than comparable onshore operations, the growing public resistance against onshore CCS projects makes sub-seabed storage a promising option. Even after a thorough review of the geological setting, there is always the possibility of leakage from the reservoir. As part of the EU-financed project CO2ReMoVe (Research, Monitoring, Verification), which aims to develop innovative research and technologies for monitoring and verification of carbon dioxide geological storage, we are working on the development of submarine long-term gas flow monitoring systems. The basic design of the monitoring system builds on our experience in volcano monitoring. Early prototypes were composed of a raft floating on the surface of a mud volcano, carrying sensors for CO2 flux and concentration, data storage and transmission, and power supply by battery-buffered solar panels. The system was modified for installation in open sea by using a buoy instead of a raft and a funnel on the seafloor to collect the gas, connected by a flexible tube. This setup provides a cost-effective solution for shallow waters. However, a buoy interferes with ship traffic, and it is also difficult to adapt this design to greater water depths. These requirements can best be complied by a completely submersed system. A system for unattended long-term monitoring in a marine environment has to be extremely durable. Therefore, we focussed on developing a mechanically and electrically as simple setup as possible, which has the additional advantage of low cost. The system consists of a funnel-shaped gas collector, a sensor head and pressure housings for electronics and power supply. Since this setup is inexpensive, it can be deployed in numbers to cover larger areas. By addition of multi-channel data loggers, data

  12. Fast detection of leakages. Ultrasonic sensors: Fast and reliable detection of leakages in compressed-air networks; Schnelle Fehlerortung. Leckagen in Druckluftnetzen mit Ultraschallsensoren zuverlaessig detektieren

    Energy Technology Data Exchange (ETDEWEB)

    Muench, H.J.; Streuber, W. [Sonotec Ultraschallsensorik GmbH, Halle/Saale (Germany)

    2002-03-18

    Leakage points can be detected easily even at high production noise levels. Probes focusing on structure-borne noise instead of airborne noise have a wider range of applications. [German] Druckluftverluste koennen schon am Entstehungsort einfach nachgewiesen werden. Die Lecksuche ist auch bei starkem Produktionslaerm noch moeglich. Eine Koerperschallsonde anstelle der Luftschallsonde bietet weitere Einsatzmoeglichkeiten. (orig.)

  13. Asphalts and asphaltenes: Macromolecular structure, precipitation properties, and flow in porous media

    Science.gov (United States)

    Rassamdana, Hossein

    Depending on rock and fluid properties, more than 50% of reservoir oil in place is normally produced by enhanced oil recovery (EOR) methods. Among the EOR techniques, miscible flooding is one of the most efficient and widely-used methods. However, this method can suffer from the formation and precipitation of asphalt aggregates. In addition, asphalt deposition is also a major hindrance to heavy oil production, and even primary recovery operations. Asphalt deposition can alter the reservoir rock properties, fluid saturation distribution, fluid flow properties, and eventually the ultimate oil recovery. The shortage of studies on the macromolecular structure and growth mechanisms of asphalt particles is the main reason for the unsuccessful modeling of their precipitation properties. The equivocal behavior of asphalt under some specific conditions could be the other reason. In this research we look at the problem of asphalt formation, flow, and precipitation from three different angles. We analyze extensive small-angle X-ray and neutron scattering data, precipitation data, and molecular weight distribution measurements, and show that they all suggest conclusively that asphalts and asphaltenes are fractal aggregates, and their growth mechanisms are diffusion-limited particle (DLP) and diffusion-limited cluster-cluster (DLCC) aggregation processes. These results lead us to development of a scaling equation of state for predicting asphalt precipitation properties, such as its onset and amount of precipitation. Another result of our study is an analytical equation for modeling the molecular weight distribution of asphalt and asphaltene aggregates. In addition, asphalt phase behavior in miscible and immiscible injections is studied. The effect of the governing thermodynamic factors, such as the pressure, temperature, and composition of the oil and precipitation agents, on the asphalt aggregation and disaggregation processes are investigated. Finally, a model is developed to

  14. Enhanced conjugation stability and blood circulation time of macromolecular gadolinium-DTPA contrast agent

    Energy Technology Data Exchange (ETDEWEB)

    Jenjob, Ratchapol [Department of New Drug Development, School of Medicine, Inha University, 2F A-dong, Jeongseok Bldg., Sinheung-dong 3-ga, Jung-gu, Incheon 400-712 (Korea, Republic of); Kun, Na [Department of Biotechnology, The Catholic University of Korea, 43 Jibong-ro, Wonmi-gu, Bucheon-si, Gyeonggi-do 420-743 (Korea, Republic of); Ghee, Jung Yeon [Utah-Inha DDS and Advanced Therapeutics, B-403 Meet-You-All Tower, SongdoTechnopark, 7–50, Songdo-dong, Yeonsu-gu, Incheon 406-840 (Korea, Republic of); Shen, Zheyu; Wu, Xiaoxia [Division of Functional Materials and Nano-Devices, Ningbo Institute of Materials Technology & Engineering (NIMTE), Chinese Academy of Sciences, 519 Zhuangshi Street, Zhenhai District, Ningbo, Zhejiang 315201 (China); Cho, Steve K., E-mail: scho@gist.ac.kr [Division of Liberal Arts and Science, GIST College, Gwangju Institute of Science and Technology, Gwangju 500-712 (Korea, Republic of); Lee, Don Haeng [Utah-Inha DDS and Advanced Therapeutics, B-403 Meet-You-All Tower, SongdoTechnopark, 7–50, Songdo-dong, Yeonsu-gu, Incheon 406-840 (Korea, Republic of); Department of Internal Medicine, School of Medicine, Inha University Hospital, Incheon 420-751 (Korea, Republic of); Yang, Su-Geun, E-mail: Sugeun.Yang@Inha.ac.kr [Department of New Drug Development, School of Medicine, Inha University, 2F A-dong, Jeongseok Bldg., Sinheung-dong 3-ga, Jung-gu, Incheon 400-712 (Korea, Republic of)

    2016-04-01

    In this study, we prepared macromolecular MR T1 contrast agent: pullulan-conjugated Gd diethylene triamine pentaacetate (Gd-DTPA-Pullulan) and estimated residual free Gd{sup 3+}, chelation stability in competition with metal ions, plasma and tissue pharmacokinetics, and abdominal MR contrast on rats. Residual free Gd{sup 3+} in Gd-DTPA-Pullulan was measured using colorimetric spectroscopy. The transmetalation of Gd{sup 3+} incubated with Ca{sup 2+} was performed by using a dialysis membrane (MWCO 100–500 Da) and investigated by ICP-OES. The plasma concentration profiles of Gd-DTPA-Pullulan were estimated after intravenous injection at a dose 0.1 mmol/kg of Gd. The coronal-plane abdominal images of normal rats were observed by MR imaging. The content of free Gd{sup 3+}, the toxic residual form, was less than 0.01%. Chelation stability of Gd-DTPA-Pullulan was estimated, and only 0.2% and 0.00045% of Gd{sup 3+} were released from Gd-DTPA-Pullulan after 2 h incubation with Ca{sup 2+} and Fe{sup 2+}, respectively. Gd-DTPA-Pullulan displayed the extended plasma half-life (t{sub 1/2,α} = 0.43 h, t{sub 1/2,β} = 2.32 h), much longer than 0.11 h and 0.79 h of Gd-EOB-DTPA. Abdominal MR imaging showed Gd-DTPA-Pullulan maintained initial MR contrast for 30 min. The extended plasma half-life of Gd-DTPA-Pullulan probably allows the prolonged MR acquisition time in clinic with enhanced MR contrast. - Highlights: • Macromolecule (pullulan) conjugated Gd contrast agent (Gd-DTPA-Pullulan) showed the extended plasma half-life (t{sub 1/2,α} = 0.43 h, t{sub 1/2,β} = 2.32 h) in comparison with Gd-EOB-DTPA • Gd-DTPA-pullulan T1 contrast agent exhibited strong chelation stability against Gd. • The extended blood circulation attributed the enhanced and prolonged MR contrast on abdominal region of rats. • The extended blood circulation may provide prolonged MR acquisition time window in clinics.

  15. Photon-counting single-molecule spectroscopy for studying conformational dynamics and macromolecular interactions

    Energy Technology Data Exchange (ETDEWEB)

    Laurence, Ted Alfred

    2002-07-30

    Single-molecule methods have the potential to provide information about conformational dynamics and molecular interactions that cannot be obtained by other methods. Removal of ensemble averaging provides several benefits, including the ability to detect heterogeneous populations and the ability to observe asynchronous reactions. Single-molecule diffusion methodologies using fluorescence resonance energy transfer (FRET) are developed to monitor conformational dynamics while minimizing perturbations introduced by interactions between molecules and surfaces. These methods are used to perform studies of the folding of Chymotrypsin Inhibitor 2, a small, single-domain protein, and of single-stranded DNA (ssDNA) homopolymers. Confocal microscopy is used in combination with sensitive detectors to detect bursts of photons from fluorescently labeled biomolecules as they diffuse through the focal volume. These bursts are analyzed to extract fluorescence resonance energy transfer (FRET) efficiency. Advances in data acquisition and analysis techniques that are providing a more complete picture of the accessible molecular information are discussed. Photon Arrival-time Interval Distribution (PAID) analysis is a new method for monitoring macromolecular interactions by fluorescence detection with simultaneous determination of coincidence, brightness, diffusion time, and occupancy (proportional to concentration) of fluorescently-labeled molecules undergoing diffusion in a confocal detection volume. This method is based on recording the time of arrival of all detected photons, and then plotting the two-dimensional histogram of photon pairs, where one axis is the time interval between each pair of photons 1 and 2, and the second axis is the number of other photons detected in the time interval between photons 1 and 2. PAID is related to Fluorescence Correlation Spectroscopy (FCS) by a collapse of this histogram onto the time interval axis. PAID extends auto- and cross-correlation FCS

  16. Photon-counting single-molecule spectroscopy for studying conformational dynamics and macromolecular interactions

    Energy Technology Data Exchange (ETDEWEB)

    Laurence, Ted Alfred [Univ. of California, Berkeley, CA (United States)

    2002-01-01

    Single-molecule methods have the potential to provide information about conformational dynamics and molecular interactions that cannot be obtained by other methods. Removal of ensemble averaging provides several benefits, including the ability to detect heterogeneous populations and the ability to observe asynchronous reactions. Single-molecule diffusion methodologies using fluorescence resonance energy transfer (FRET) are developed to monitor conformational dynamics while minimizing perturbations introduced by interactions between molecules and surfaces. These methods are used to perform studies of the folding of Chymotrypsin Inhibitor 2, a small, single-domain protein, and of single-stranded DNA (ssDNA) homopolymers. Confocal microscopy is used in combination with sensitive detectors to detect bursts of photons from fluorescently labeled biomolecules as they diffuse through the focal volume. These bursts are analyzed to extract fluorescence resonance energy transfer (FRET) efficiency. Advances in data acquisition and analysis techniques that are providing a more complete picture of the accessible molecular information are discussed. Photon Arrival-time Interval Distribution (PAID) analysis is a new method for monitoring macromolecular interactions by fluorescence detection with simultaneous determination of coincidence, brightness, diffusion time, and occupancy (proportional to concentration) of fluorescently-labeled molecules undergoing diffusion in a confocal detection volume. This method is based on recording the time of arrival of all detected photons, and then plotting the two-dimensional histogram of photon pairs, where one axis is the time interval between each pair of photons 1 and 2, and the second axis is the number of other photons detected in the time interval between photons 1 and 2. PAID is related to Fluorescence Correlation Spectroscopy (FCS) by a collapse of this histogram onto the time interval axis. PAID extends auto- and cross-correlation FCS

  17. Macromolecular crowding gives rise to microviscosity, anomalous diffusion and accelerated actin polymerization

    Science.gov (United States)

    Rashid, Rafi; Chee, Stella Min Ling; Raghunath, Michael; Wohland, Thorsten

    2015-05-01

    Macromolecular crowding (MMC) has been used in various in vitro experimental systems to mimic in vivo physiology. This is because the crowded cytoplasm of cells contains many different types of solutes dissolved in an aqueous medium. MMC in the extracellular microenvironment is involved in maintaining stem cells in their undifferentiated state (niche) as well as in aiding their differentiation after they have travelled to new locations outside the niche. MMC at physiologically relevant fractional volume occupancies (FVOs) significantly enhances the adipogenic differentiation of human bone marrow-derived mesenchymal stem cells during chemically induced adipogenesis. The mechanism by which MMC produces this enhancement is not entirely known. In the context of extracellular collagen deposition, we have recently reported the importance of optimizing the FVO while minimizing the bulk viscosity. Two opposing properties will determine the net rate of a biochemical reaction: the negative effect of bulk viscosity and the positive effect of the excluded volume, the latter being expressed by the FVO. In this study we have looked more closely at the effect of viscosity on reaction rates. We have used fluorimetry to measure the rate of actin polymerization and fluorescence correlation spectroscopy (FCS) to measure diffusion of various probes in solutions containing the crowder Ficoll at physiological concentrations. Similar to its effect on collagen, Ficoll enhanced the actin polymerization rate despite increasing the bulk viscosity. Our FCS measurements reveal a relatively minor component of anomalous diffusion. In addition, our measurements do suggest that microviscosity becomes relevant in a crowded environment. We ruled out bulk viscosity as a cause of the rate enhancement by performing the actin polymerization assay in glycerol. These opposite effects of Ficoll and glycerol led us to conclude that microviscosity becomes relevant at the length scale of the reacting

  18. Leaching of organic acids from macromolecular organic matter by non-supercritical CO2

    Science.gov (United States)

    Sauer, P.; Glombitza, C.; Kallmeyer, J.

    2012-04-01

    The storage of CO2 in underground reservoirs is discussed controversly in the scientific literature. The worldwide search for suitable storage formations also considers coal-bearing strata. CO2 is already injected into seams for enhanced recovery of coal bed methane. However, the effects of increased CO2 concentration, especially on organic matter rich formations, are rarely investigated. The injected CO2 will dissolve in the pore water, causing a decrease in pH and resulting in acidic formation waters. Huge amounts of low molecular weight organic acids (LMWOAs) are chemically bound to the macromolecular matrix of sedimentary organic matter and may be liberated by hydrolysis, which is enhanced by the acidic porewater. Recent investigations outlined the importance of LMWOAs as a feedstock for microbial life in the subsurface [1]. Therefore, injection of CO2 into coal formations may result in enhanced nutrient supply for subsurface microbes. To investigate the effect of high concentrations of dissolved CO2 on the release of LMWOAs from coal we developed an inexpensive high-pressure high temperature system that allows manipulating the partial pressure of dissolved gases at pressures and temperatures up to 60 MPa and 120° C, respectively. In a reservoir vessel, gases are added to saturate the extraction medium to the desired level. Inside the extraction vessel hangs a flexible and inert PVDF sleeve (polyvinylidene fluoride, almost impermeable for gases), holding the sample and separating it from the pressure fluid. The flexibility of the sleeve allows for subsampling without loss of pressure. Coal samples from the DEBITS-1 well, Waikato Basin, NZ (R0 = 0.29, TOC = 30%). were extracted at 90° C and 5 MPa, either with pure or CO2-saturated water. Subsamples were taken at different time points during the extraction. The extracted LMWOAs such as formate, acetate and oxalate were analysed by ion chromatography. Yields of LMWOAs were higher with pure water than with CO2

  19. Macromolecular structures probed by combining single-shot free-electron laser diffraction with synchrotron coherent X-ray imaging.

    Science.gov (United States)

    Gallagher-Jones, Marcus; Bessho, Yoshitaka; Kim, Sunam; Park, Jaehyun; Kim, Sangsoo; Nam, Daewoong; Kim, Chan; Kim, Yoonhee; Noh, Do Young; Miyashita, Osamu; Tama, Florence; Joti, Yasumasa; Kameshima, Takashi; Hatsui, Takaki; Tono, Kensuke; Kohmura, Yoshiki; Yabashi, Makina; Hasnain, S Samar; Ishikawa, Tetsuya; Song, Changyong

    2014-05-02

    Nanostructures formed from biological macromolecular complexes utilizing the self-assembly properties of smaller building blocks such as DNA and RNA hold promise for many applications, including sensing and drug delivery. New tools are required for their structural characterization. Intense, femtosecond X-ray pulses from X-ray free-electron lasers enable single-shot imaging allowing for instantaneous views of nanostructures at ambient temperatures. When combined judiciously with synchrotron X-rays of a complimentary nature, suitable for observing steady-state features, it is possible to perform ab initio structural investigation. Here we demonstrate a successful combination of femtosecond X-ray single-shot diffraction with an X-ray free-electron laser and coherent diffraction imaging with synchrotron X-rays to provide an insight into the nanostructure formation of a biological macromolecular complex: RNA interference microsponges. This newly introduced multimodal analysis with coherent X-rays can be applied to unveil nano-scale structural motifs from functional nanomaterials or biological nanocomplexes, without requiring a priori knowledge.

  20. SYNTHESIS OF STYRYL-CAPPED POLYPROPYLENE via METALLOCENE-MEDIATED COORDINATION POLYMERIZATION: APPLY TO POLYPROPYLENE MACROMOLECULAR ENGINEERING

    Institute of Scientific and Technical Information of China (English)

    Hua-hua Huang; Chuan-hui Zhang; Ya-wei Qin; Hui Niu; Jin-yong Dong

    2013-01-01

    In this paper,we review our recent progress in the synthesis and application of styryl-capped polypropylene (PP-tSt),an excellent reactive polyolefin that is both convenient and efficient in synthesis and facile and versatile in application for preparing advanced polypropylene materials via macromolecular engineering.The synthesis of PP-t-St is made possible by a unique chain transfer reaction coordinated by a bis-styrenic molecule,such as 1,4-divinylbenzene (DVB) and 1,2-bis(4-vinylphenyl)ethane (BVPE),and hydrogen in typical C2-symmetric metallocene (e.g.rac-Me2Si(2-Me-4-Ph-Ind)2ZrC12,in association with methylaluminocene,MAO) catalyzed propylene polymerization.The regio-selective 2,1-insertion of the styrenic double bond in DVB or BVPE into the overwhelmingly 1,2-fashioned Zr-PP propagating chain enables substantial dormancy of the catalyst active site,which triggers selective hydrogen chain transfer that,with the formed Zr-H species ultimately saturated by the insertion of propylene monomer,results in an exclusive capping of the afforded PP chains by styryl group at the termination end.With a highly reactive styryl group at chain end,PP-t-St has been used as a facile building block in PP macromolecular engineering together with the employment of state-of-the-art synthetic polymer chemistry to fabricate broad types of new polypropylene architectures.