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Sample records for repair systems molecular

  1. Molecular dialogues between the ischemic brain and the peripheral immune system: Dualistic roles in injury and repair

    Science.gov (United States)

    An, Chengrui; Shi, Yejie; Li, Peiying; Hu, Xiaoming; Gan, Yu; Stetler, Ruth A.; Leak, Rehana K.; Gao, Yanqin; Sun, Bao-Liang; Zheng, Ping; Chen, Jun

    2014-01-01

    Immune and inflammatory responses actively modulate the pathophysiological processes of acute brain injuries such as stroke. Soon after the onset of stroke, signals such as brain-derived antigens, danger-associated molecular patterns (DAMPs), cytokines, and chemokines are released from the injured brain into the systemic circulation. The injured brain also communicates with peripheral organs through the parasympathetic and sympathetic branches of the autonomic nervous system. Many of these diverse signals not only activate resident immune cells in the brain, but also trigger robust immune responses in the periphery. Peripheral immune cells then migrate toward the site of injury and release additional cytokines, chemokines, and other molecules, causing further disruptive or protective effects in the ischemic brain. Bidirectional communication between the injured brain and the peripheral immune system is now known to regulate the progression of stroke pathology as well as tissue repair. In the end, this exquisitely coordinated crosstalk helps determine the fate of animals after stroke. This article reviews the literature on ischemic brain-derived signals through which peripheral immune responses are triggered, and the potential impact of these peripheral responses on brain injury and repair. Pharmacological strategies and cell-based therapies that target the dialogue between the brain and peripheral immune system show promise as potential novel treatments for stroke. PMID:24374228

  2. Molecular dialogs between the ischemic brain and the peripheral immune system: dualistic roles in injury and repair.

    Science.gov (United States)

    An, Chengrui; Shi, Yejie; Li, Peiying; Hu, Xiaoming; Gan, Yu; Stetler, Ruth A; Leak, Rehana K; Gao, Yanqin; Sun, Bao-Liang; Zheng, Ping; Chen, Jun

    2014-04-01

    Immune and inflammatory responses actively modulate the pathophysiological processes of acute brain injuries such as stroke. Soon after the onset of stroke, signals such as brain-derived antigens, danger-associated molecular patterns (DAMPs), cytokines, and chemokines are released from the injured brain into the systemic circulation. The injured brain also communicates with peripheral organs through the parasympathetic and sympathetic branches of the autonomic nervous system. Many of these diverse signals not only activate resident immune cells in the brain, but also trigger robust immune responses in the periphery. Peripheral immune cells then migrate toward the site of injury and release additional cytokines, chemokines, and other molecules, causing further disruptive or protective effects in the ischemic brain. Bidirectional communication between the injured brain and the peripheral immune system is now known to regulate the progression of stroke pathology as well as tissue repair. In the end, this exquisitely coordinated crosstalk helps determine the fate of animals after stroke. This article reviews the literature on ischemic brain-derived signals through which peripheral immune responses are triggered, and the potential impact of these peripheral responses on brain injury and repair. Pharmacological strategies and cell-based therapies that target the dialog between the brain and peripheral immune system show promise as potential novel treatments for stroke. Published by Elsevier Ltd.

  3. Molecular biological mechanisms I. DNA repair

    International Nuclear Information System (INIS)

    Friedl, A.A.

    2000-01-01

    Cells of all living systems possess a variety of mechanisms that allow to repair spontaneous and exogeneously induced DNA damage. DNA repair deficiencies may invoke enhanced sensitivity towards DNA-damaging agents such as ionizing radiation. They may also enhance the risk of cancer development, both spontaneously or after induction. This article reviews several DNA repair mechanisms, especially those dealing with DNA double-strand breaks, and describes hereditary diseases associated with DNA repair defects. (orig.) [de

  4. Molecular mechanism of short-patch repair of radiation-damaged DNA by in vitro reconstituted systems

    International Nuclear Information System (INIS)

    Matsumoto, Y.; Kim, K.; Biade, S.

    1995-01-01

    Objective: Short-patch excision repair is the major pathway to correct DNA damage such as modified bases, apurinic/apyrimidinic (AP) sites and single-strand breaks. Recently this repair reaction was demonstrated to proceed by two alternative pathways: DNA polymerase β (pol β)-dependent pathway and proliferating cell nuclear antigen (PCNA)-dependent pathway. In this work, we focused to compare substrate specificity of these two repair pathways and elucidate their roles in cellular responses to radiation damage. Materials and Methods: Three protein fractions, AP endonuclease, pol β, and BE-1B, which are required for the pol β-dependent pathway, and five protein fractions, AP endonuclease, BE-1B (these two are common to the pol β-dependent pathway), PCNA, pol δ, and BE-2, which are essential for the PCNA-dependent pathway were obtained from Xenopus laevis ovaries through column chromatography. The circular DNA containing either one of the following three lesions: a natural AP site, its synthetic analog, 3-hydroxy-2-hydroxymethyltetrahydrofuran (tetrahydrofuran), and 5-iododeoxyuridine (IdU), was prepared by in vitro ligation of oligonucleotides to a gapped circular DNA. The IdU-containing DNA was irradiated with 312 nm UV light prior to repair reaction. In addition, DNA carrying a single-strand break was obtained by Cs-137 irradiation. Repair reactions of these substrate DNAs were conducted with either the reconstituted system for the pol β-dependent pathway or the one for the PCNA-dependent pathway. After the reaction, repaired and unrepaired DNAs were separated by gel electrophoresis and quantitated. Results: The pol β-dependent reconstituted system was able to repair natural AP sites but not tetrahydrofuran sites or UV-irradiated IdU. The single-strand breaks generated by γ-irradiation were partially repaired by thepol β-dependent pathway. The PCNA-dependent system was able to repair natural AP sites, tetrahydrofuran sites, and most of the single

  5. Composite Repair System, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — GTL has developed an innovative composite repair methodology known as the Composite Repair System (CRS). In this phase I effort, CRS is being developed for the...

  6. DNA Repair Systems

    Indian Academy of Sciences (India)

    DNA molecule which makes it ideal for storage and propagation of genetic information. ... of these errors are broadly referred to as DNA repair. DNA can ... changes occur in the human genome per day. ..... nails, frequent physical and mental.

  7. DNA Repair Systems

    Indian Academy of Sciences (India)

    Thanks to the pioneering research work of Lindahl, Sancar, Modrich and their colleagues, we now have an holistic awareness of how DNA damage occurs and how the damage is rectified in bacteria as well as in higher organisms including human beings. A comprehensive understanding of DNA repair has proven crucial ...

  8. A model system for DNA repair studies

    International Nuclear Information System (INIS)

    Lange, C.S.; Perlmutter, E.

    1984-01-01

    The search for the ''lethal lesion:'' which would yield a molecular explanation of biological survival curves led to attempts to correlate unrepaired DNA lesions with loss of reproductive integrity. Such studies have shown the crucial importance of DNA repair systems. The unrepaired DSB has been sought for such correlation, but in such study the DNA was too large, polydisperse, and/or structurally complex to permit precise measurement of break induction and repair. Therefore, an analog of higher order systems but with a genome of readily measurable size, is needed. Bacteriophage T4 is such an analog. Both its biological (PFU) and molecular (DNA) survival curves are exponentials. Its aerobic /sub PFU/D/sub 37///sub DNA/D/sub 37/ ratio, (410 +- 4.5Gy/540 +- 25 Gy) indicates that 76 +- 4% of lethality at low multiplicity infection (moi 1) the survival is greater than can be explained if the assumption of no parental DSB repair were valid. Both T4 and its host have DSB repair systems which can be studied by the infectious center method. Results of such studies are discussed

  9. Reward optimization of a repairable system

    Energy Technology Data Exchange (ETDEWEB)

    Castro, I.T. [Departamento de Matematicas, Facultad de Veterinaria, Universidad de Extremadura, Avenida de la Universidad, s/n. 10071 Caceres (Spain)]. E-mail: inmatorres@unex.es; Perez-Ocon, R. [Departamento de Estadistica e Investigacion Operativa, Facultad de Ciencias, Universidad de Granada, Avenida de Severo Ochoa, s/n. 18071 Granada (Spain)]. E-mail: rperezo@ugr.es

    2006-03-15

    This paper analyzes a system subject to repairable and non-repairable failures. Non-repairable failures lead to replacement of the system. Repairable failures, first lead to repair but they lead to replacement after a fixed number of repairs. Operating and repair times follow phase type distributions (PH-distributions) and the pattern of the operating times is modelled by a geometric process. In this context, the problem is to find the optimal number of repairs, which maximizes the long-run average reward per unit time. To this end, the optimal number is determined and it is obtained by efficient numerical procedures.

  10. Reward optimization of a repairable system

    International Nuclear Information System (INIS)

    Castro, I.T.; Perez-Ocon, R.

    2006-01-01

    This paper analyzes a system subject to repairable and non-repairable failures. Non-repairable failures lead to replacement of the system. Repairable failures, first lead to repair but they lead to replacement after a fixed number of repairs. Operating and repair times follow phase type distributions (PH-distributions) and the pattern of the operating times is modelled by a geometric process. In this context, the problem is to find the optimal number of repairs, which maximizes the long-run average reward per unit time. To this end, the optimal number is determined and it is obtained by efficient numerical procedures

  11. Molecular dosimetry of chemical mutagens: measurement of molecular dose and DNA repair germ cells

    International Nuclear Information System (INIS)

    Sega, G.A.

    1975-01-01

    Molecular dosimetry in the germ cells of male mice is reviewed with regard to in vivo alkylation of sperm heads, in vivo alkylation of sperm DNA, and possible alkylation of sperm protamine. DNA repair in male germ cells is reviewed with regard to basic design of experiments, DNA repair in various stages of spermatogenesis, effect of protamine on DNA repair following treatment with EMS or x radiation, and induction of DNA repair by methyl methanesulfonate, propyl methanesulfonate, and isopropyl methanesulfonate

  12. Using repair priorities in systems with redundacies

    NARCIS (Netherlands)

    Sleptchenko, A.V.; Adan, I.J.B.F.; Van Houtum, G.-J.

    2014-01-01

    In this paper, we present and analyze a mathematical model for the computation of the system availability for a system of parallel machines with redundancies and repair priorities. Using the presented models, we show that the repair priorities have a strong effect on the performance of the system.

  13. Stochastic Modelling Of The Repairable System

    Directory of Open Access Journals (Sweden)

    Andrzejczak Karol

    2015-11-01

    Full Text Available All reliability models consisting of random time factors form stochastic processes. In this paper we recall the definitions of the most common point processes which are used for modelling of repairable systems. Particularly this paper presents stochastic processes as examples of reliability systems for the support of the maintenance related decisions. We consider the simplest one-unit system with a negligible repair or replacement time, i.e., the unit is operating and is repaired or replaced at failure, where the time required for repair and replacement is negligible. When the repair or replacement is completed, the unit becomes as good as new and resumes operation. The stochastic modelling of recoverable systems constitutes an excellent method of supporting maintenance related decision-making processes and enables their more rational use.

  14. Diverless pipeline repair system for deep water

    Energy Technology Data Exchange (ETDEWEB)

    Spinelli, Carlo M. [Eni Gas and Power, Milan (Italy); Fabbri, Sergio; Bachetta, Giuseppe [Saipem/SES, Venice (Italy)

    2009-07-01

    SiRCoS (Sistema Riparazione Condotte Sottomarine) is a diverless pipeline repair system composed of a suite of tools to perform a reliable subsea pipeline repair intervention in deep and ultra deep water which has been on the ground of the long lasting experience of Eni and Saipem in designing, laying and operating deep water pipelines. The key element of SiRCoS is a Connection System comprising two end connectors and a repair spool piece to replace a damaged pipeline section. A Repair Clamp with elastomeric seals is also available for pipe local damages. The Connection System is based on pipe cold forging process, consisting in swaging the pipe inside connectors with suitable profile, by using high pressure seawater. Three swaging operations have to be performed to replace the damaged pipe length. This technology has been developed through extensive theoretical work and laboratory testing, ending in a Type Approval by DNV over pipe sizes ranging from 20 inches to 48 inches OD. A complete SiRCoS system has been realised for the Green Stream pipeline, thoroughly tested in workshop as well as in shallow water and is now ready, in the event of an emergency situation.The key functional requirements for the system are: diverless repair intervention and fully piggability after repair. Eni owns this technology and is now available to other operators under Repair Club arrangement providing stand-by repair services carried out by Saipem Energy Services. The paper gives a description of the main features of the Repair System as well as an insight into the technological developments on pipe cold forging reliability and long term duration evaluation. (author)

  15. Regression Models for Repairable Systems

    Czech Academy of Sciences Publication Activity Database

    Novák, Petr

    2015-01-01

    Roč. 17, č. 4 (2015), s. 963-972 ISSN 1387-5841 Institutional support: RVO:67985556 Keywords : Reliability analysis * Repair models * Regression Subject RIV: BB - Applied Statistics, Operational Research Impact factor: 0.782, year: 2015 http://library.utia.cas.cz/separaty/2015/SI/novak-0450902.pdf

  16. Systems Maintenance Automated Repair Tasks (SMART)

    Science.gov (United States)

    Schuh, Joseph; Mitchell, Brent; Locklear, Louis; Belson, Martin A.; Al-Shihabi, Mary Jo Y.; King, Nadean; Norena, Elkin; Hardin, Derek

    2010-01-01

    SMART is a uniform automated discrepancy analysis and repair-authoring platform that improves technical accuracy and timely delivery of repair procedures for a given discrepancy (see figure a). SMART will minimize data errors, create uniform repair processes, and enhance the existing knowledge base of engineering repair processes. This innovation is the first tool developed that links the hardware specification requirements with the actual repair methods, sequences, and required equipment. SMART is flexibly designed to be useable by multiple engineering groups requiring decision analysis, and by any work authorization and disposition platform (see figure b). The organizational logic creates the link between specification requirements of the hardware, and specific procedures required to repair discrepancies. The first segment in the SMART process uses a decision analysis tree to define all the permutations between component/ subcomponent/discrepancy/repair on the hardware. The second segment uses a repair matrix to define what the steps and sequences are for any repair defined in the decision tree. This segment also allows for the selection of specific steps from multivariable steps. SMART will also be able to interface with outside databases and to store information from them to be inserted into the repair-procedure document. Some of the steps will be identified as optional, and would only be used based on the location and the current configuration of the hardware. The output from this analysis would be sent to a work authoring system in the form of a predefined sequence of steps containing required actions, tools, parts, materials, certifications, and specific requirements controlling quality, functional requirements, and limitations.

  17. Systems with randomly failing repairable components

    DEFF Research Database (Denmark)

    Der Kiureghian, Armen; Ditlevsen, Ove Dalager; Song, Junho

    2005-01-01

    Closed-form expressions are derived for the steady-state availability, mean rate of failure, mean duration of downtime and reliability of a general system with randomly and independently failing repairable components. Component failures are assumed to be homogeneous Poisson events in time and rep...

  18. Self-repair of cracks in brittle material systems

    Science.gov (United States)

    Dry, Carolyn M.

    2016-04-01

    One of the most effective uses for self repair is in material systems that crack because the cracks can allow the repair chemical to flow into the crack damage sites in all three dimensions. In order for the repair chemical to stay in the damage site and flow along to all the crack and repair there must be enough chemical to fill the entire crack. The repair chemical must be designed appropriately for the particular crack size and total volume of cracks. In each of the three examples of self repair in crackable brittle systems, the viscosity and chemical makeup and volume of the repair chemicals used is different for each system. Further the chemical delivery system has to be designed for each application also. Test results from self repair of three brittle systems are discussed. In "Self Repair of Concrete Bridges and Infrastructure" two chemicals were used due to different placements in bridges to repair different types of cracks- surface shrinkage and shear cracks, In "Airplane Wings and Fuselage, in Graphite" the composite has very different properties than the concrete bridges. In the graphite for airplane components the chemical also had to survive the high processing temperatures. In this composite the cracks were so definite and deep and thin that the repair chemical could flow easily and repair in all layers of the composite. In "Ceramic/Composite Demonstrating Self Repair" the self repair system not only repaired the broken ceramic but also rebounded the composite to the ceramic layer

  19. Molecular dynamics of formation of TD lesioned DNA complexed with repair enzyme - onset of the enzymatic repair process

    Energy Technology Data Exchange (ETDEWEB)

    Pinak, Miroslav [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1999-12-01

    To describe the first step of the enzymatic repair process (formation of complex enzyme-DNA), in which the thymine dimer (TD) part is removed from DNA, the 500 picosecond (ps) molecular dynamics (MD) simulation of TD lesioned DNA and part of repair enzyme cell (inclusive of catalytic center - Arg-22, Glu-23, Arg-26 and Thr-2) was performed. TD is UV originated lesion in DNA and T4 Endonuclease V is TD specific repair enzyme. Both molecules were located in the same simulation cell and their relative movement was examined. During the simulation the research was focused on the role of electrostatic energy in formation of complex enzyme-DNA. It is found, that during the first 100 ps of MD, the part of enzyme approaches the DNA surface at the TD lesion, interacts extensively by electrostatic and van der Walls interactions with TD part of DNA and forms complex that lasts stabile for 500 ps of MD. In the beginning of MD, the positive electrostatic interaction energy between part of enzyme and TD ({approx} +10 kcal/mol) drives enzyme towards the DNA molecule. Water-mediated hydrogen bonds between enzyme and DNA help to keep complex stabile. As a reference, the MD simulation of the identical system with native DNA molecule (two native thymines (TT) instead of TD) was performed. In this system the negative electrostatic interaction energy between part of enzyme and TT ({approx} -11 kcal/mol), in contrary to the positive one in the system with TD, doesn't drive enzyme towards DNA and complex is not formed. (author)

  20. Molecular dynamics of formation of TD lesioned DNA complexed with repair enzyme - onset of the enzymatic repair process

    International Nuclear Information System (INIS)

    Pinak, Miroslav

    1999-12-01

    To describe the first step of the enzymatic repair process (formation of complex enzyme-DNA), in which the thymine dimer (TD) part is removed from DNA, the 500 picosecond (ps) molecular dynamics (MD) simulation of TD lesioned DNA and part of repair enzyme cell (inclusive of catalytic center - Arg-22, Glu-23, Arg-26 and Thr-2) was performed. TD is UV originated lesion in DNA and T4 Endonuclease V is TD specific repair enzyme. Both molecules were located in the same simulation cell and their relative movement was examined. During the simulation the research was focused on the role of electrostatic energy in formation of complex enzyme-DNA. It is found, that during the first 100 ps of MD, the part of enzyme approaches the DNA surface at the TD lesion, interacts extensively by electrostatic and van der Walls interactions with TD part of DNA and forms complex that lasts stabile for 500 ps of MD. In the beginning of MD, the positive electrostatic interaction energy between part of enzyme and TD (∼ +10 kcal/mol) drives enzyme towards the DNA molecule. Water-mediated hydrogen bonds between enzyme and DNA help to keep complex stabile. As a reference, the MD simulation of the identical system with native DNA molecule (two native thymines (TT) instead of TD) was performed. In this system the negative electrostatic interaction energy between part of enzyme and TT (∼ -11 kcal/mol), in contrary to the positive one in the system with TD, doesn't drive enzyme towards DNA and complex is not formed. (author)

  1. A geometric process repair model for a repairable cold standby system with priority in use and repair

    International Nuclear Information System (INIS)

    Zhang Yuanlin; Wang Guanjun

    2009-01-01

    In this paper, a deteriorating cold standby repairable system consisting of two dissimilar components and one repairman is studied. For each component, assume that the successive working times form a decreasing geometric process while the consecutive repair times constitute an increasing geometric process, and component 1 has priority in use and repair. Under these assumptions, we consider a replacement policy N based on the number of repairs of component 1 under which the system is replaced when the number of repairs of component 1 reaches N. Our problem is to determine an optimal policy N* such that the average cost rate (i.e. the long-run average cost per unit time) of the system is minimized. The explicit equation of the average cost rate of the system is derived and the corresponding optimal replacement policy N* can be determined analytically or numerically. Finally, a numerical example with Weibull distribution is given to illustrate some theoretical results in this paper.

  2. Analysis for a two-dissimilar-component cold standby repairable system with repair priority

    International Nuclear Information System (INIS)

    Leung, Kit Nam Francis; Zhang Yuanlin; Lai, Kin Keung

    2011-01-01

    In this paper, a cold standby repairable system consisting of two dissimilar components and one repairman is studied. Assume that working time distributions and repair time distributions of the two components are both exponential, and Component 1 has repair priority when both components are broken down. After repair, Component 1 follows a geometric process repair while Component 2 obeys a perfect repair. Under these assumptions, using the perfect repair model, the geometric process repair model and the supplementary variable technique, we not only study some important reliability indices, but also consider a replacement policy T, under which the system is replaced when the working age of Component 1 reaches T. Our problem is to determine an optimal policy T* such that the long-run average loss per unit time (i.e. average loss rate) of the system is minimized. The explicit expression for the average loss rate of the system is derived, and the corresponding optimal replacement policy T* can be found numerically. Finally, a numerical example for replacement policy T is given to illustrate some theoretical results and the model's applicability. - Highlights: → A two-dissimilar-component cold standby system with repair priority is formulated. → The successive up/repair times of Component 1 form a decreasing/increasing geometric process. → Not only some reliability indices but also a replacement policy are studied.

  3. Failure Modes in Concrete Repair Systems due to Ongoing Corrosion

    Directory of Open Access Journals (Sweden)

    Mladena Luković

    2017-01-01

    Full Text Available Corrosion of steel reinforcement is the main cause of deterioration in reinforced concrete structures. It can result in cracking and spalling of the concrete cover. After the damaged cover is repaired, reinforcement corrosion might continue and even accelerate. While the development of the corrosion cell is difficult to control, the damage can be possibly delayed and controlled by use of a suitable repair material. The lattice fracture model is used in this paper to investigate the performance of strain hardening cementitious composite (SHCC in concrete repair systems exposed to ongoing corrosion. Numerical results were verified by experimental tests when SHCC, nonreinforced material (repair mortar, and commercial repair mortar are used as repair materials. In experiments, reinforcement bars (surrounded by a repair material were exposed to accelerated corrosion tests. The influence of the substrate surface preparation, the type of repair material, the interface, and the substrate strength on the resulting damage and failure mode of repair systems are discussed. In general, SHCC repair enables distributed cracking with small crack widths, up to several times smaller compared to repair mortar. Furthermore, more warning signs prior to the final failure are present in the SHCC repair system.

  4. Molecular mechanisms of DNA repair inhibition by caffeine

    Energy Technology Data Exchange (ETDEWEB)

    Selby, C.P.; Sancar, A. (Univ. of North Carolina School of Medicine, Chapel Hill (USA))

    1990-05-01

    Caffeine potentiates the mutagenic and lethal effects of genotoxic agents. It is thought that this is due, at least in some organisms, to inhibition of DNA repair. However, direct evidence for inhibition of repair enzymes has been lacking. Using purified Escherichia coli DNA photolyase and (A)BC excinuclease, we show that the drug inhibits photoreactivation and nucleotide excision repair by two different mechanisms. Caffeine inhibits photoreactivation by interfering with the specific binding of photolyase to damaged DNA, and it inhibits nucleotide excision repair by promoting nonspecific binding of the damage-recognition subunit, UvrA, of (A)BC excinuclease. A number of other intercalators, including acriflavin and ethidium bromide, appear to inhibit the excinuclease by a similar mechanism--that is, by trapping the UvrA subunit in nonproductive complexes on undamaged DNA.

  5. Synergetics of molecular systems

    CERN Document Server

    Lupichev, Lev N; Kadantsev, Vasiliy N

    2014-01-01

    Synergetics is the quantitative study of multicomponent systems that exhibit nonlinear dynamics and cooperativity. This book specifically considers basic models of the nonlinear dynamics of molecular systems and discusses relevant applications in biological physics and the polymer sciences.Emphasis is placed on specific solutions to the dynamical equations that correspond to the coherent formation of spatial-temporal structures, such as solitons, kinks and breathers, in particular. The emergence of these patterns in molecular structures provides a variety of information on their structural pro

  6. DNA repair systems as targets of cadmium toxicity

    International Nuclear Information System (INIS)

    Giaginis, Constantinos; Gatzidou, Elisavet; Theocharis, Stamatios

    2006-01-01

    Cadmium (Cd) is a heavy metal and a potent carcinogen implicated in tumor development through occupational and environmental exposure. Recent evidence suggests that proteins participating in the DNA repair systems, especially in excision and mismatch repair, are sensitive targets of Cd toxicity. Cd by interfering and inhibiting these DNA repair processes might contribute to increased risk for tumor formation in humans. In the present review, the information available on the interference of Cd with DNA repair systems and their inhibition is summarized. These actions could possibly explain the indirect contribution of Cd to mutagenic effects and/or carcinogenicity

  7. Mountain Plains Learning Experience Guide: Automotive Repair. Course: Brake Systems.

    Science.gov (United States)

    Schramm, C.; Osland, Walt

    One of twelve individualized courses included in an automotive repair curriculum, this course covers theory, operation, and repair of drum brakes, disc brakes, and brake system components. The course is comprised of six units: (1) Fundamentals of Brake Systems, (2) Master Cylinder, (3) Drum Brakes, (4) Disc Brakes, (5) Power Brakes, and (6)…

  8. Closed loop two-echelon repairable item systems

    NARCIS (Netherlands)

    Spanjers, L.; van Ommeren, Jan C.W.; Zijm, Willem H.M.

    In this paper we consider closed loop two-echelon repairable item systems with repair facilities both at a number of local service centers (called bases) and at a central location (the depot). The goal of the system is to maintain a number of production facilities (one at each base) in optimal

  9. Closed-loop two-echelon repairable item systems

    NARCIS (Netherlands)

    Spanjers, L.; Zijm, Willem H.M.; van Ommeren, Jan C.W.

    2003-01-01

    In this paper we consider closed loop two-echelon repairable item systems with repair facilities both at a number of local service centers (called bases) and at a central location (the depot). The goal of the system is to maintain a number of production facilities (one at each base) in optimal

  10. Reducing costs of repairable inventory supply systems via dynamic scheduling

    NARCIS (Netherlands)

    Tiemessen, H.G.H.; Houtum, van G.J.J.A.N.

    2013-01-01

    We study a system consisting of one repair shop and one stockpoint, where spare parts of multiple critical repairables are kept on stock to serve an installed base of technical systems. Part requests are met from stock if possible, and backordered otherwise. The objective is to minimize aggregate

  11. Component-Level Electronic-Assembly Repair (CLEAR) System Architecture

    Science.gov (United States)

    Oeftering, Richard C.; Bradish, Martin A.; Juergens, Jeffrey R.; Lewis, Michael J.; Vrnak, Daniel R.

    2011-01-01

    This document captures the system architecture for a Component-Level Electronic-Assembly Repair (CLEAR) capability needed for electronics maintenance and repair of the Constellation Program (CxP). CLEAR is intended to improve flight system supportability and reduce the mass of spares required to maintain the electronics of human rated spacecraft on long duration missions. By necessity it allows the crew to make repairs that would otherwise be performed by Earth based repair depots. Because of practical knowledge and skill limitations of small spaceflight crews they must be augmented by Earth based support crews and automated repair equipment. This system architecture covers the complete system from ground-user to flight hardware and flight crew and defines an Earth segment and a Space segment. The Earth Segment involves database management, operational planning, and remote equipment programming and validation processes. The Space Segment involves the automated diagnostic, test and repair equipment required for a complete repair process. This document defines three major subsystems including, tele-operations that links the flight hardware to ground support, highly reconfigurable diagnostics and test instruments, and a CLEAR Repair Apparatus that automates the physical repair process.

  12. Cellular and molecular repair of X-ray-induced damage: dependence on oxygen tension and nutritional status

    International Nuclear Information System (INIS)

    Spiro, I.J.; Kennedy, K.A.; Stickler, R.; Ling, C.C.

    1985-01-01

    Cellular and molecular repair was studied at 23 0 C using split-dose recovery and alkaline elution techniques, respectively, as a function of cellular oxygen and nutrient conditions. Hypoxic cells in full medium showed a partial reduction in the level of sublethal damage (SLD) repair relative to aerated cells; the respective repair kinetics were similar with a common repair half-time of 30 min. Similarly, hypoxic cells showed a slight reduction in strand break rejoining capacity compared to aerated cells. Under nutrient deprivation, anoxic cells displayed no SLD repair or strand break repair, while aerated cells exhibited the same level of SLD and strand break repair as for well-fed cells. In addition, nutrient deprived cells at low O 2 levels displayed normal SLD and strand break repair capability. These results indicate that both nutrient and O 2 deprivation are necessary for complete inhibition of cellular and molecular repair, and low levels of O 2 can effectively reverse this inhibition

  13. Autogenous Metallic Pipe Leak Repair in Potable Water Systems.

    Science.gov (United States)

    Tang, Min; Triantafyllidou, Simoni; Edwards, Marc A

    2015-07-21

    Copper and iron pipes have a remarkable capability for autogenous repair (self-repair) of leaks in potable water systems. Field studies revealed exemplars that metallic pipe leaks caused by nails, rocks, and erosion corrosion autogenously repaired, as confirmed in the laboratory experiments. This work demonstrated that 100% (N = 26) of 150 μm leaks contacting representative bulk potable water in copper pipes sealed autogenously via formation of corrosion precipitates at 20-40 psi, pH 3.0-11.0, and with upward and downward leak orientations. Similar leaks in carbon steel pipes at 20 psi self-repaired at pH 5.5 and 8.5, but two leaks did not self-repair permanently at pH 11.0 suggesting that water chemistry may control the durability of materials that seal the leaks and therefore the permanence of repair. Larger 400 μm holes in copper pipes had much lower (0-33%) success of self-repair at pH 3.0-11.0, whereas all 400 μm holes in carbon steel pipes at 20 psi self-repaired at pH 4.0-11.0. Pressure tests indicated that some of the repairs created at 20-40 psi ambient pressure could withstand more than 100 psi without failure. Autogenous repair has implications for understanding patterns of pipe failures, extending the lifetime of decaying infrastructure, and developing new plumbing materials.

  14. Repairing method for reactor primary system pipeline

    International Nuclear Information System (INIS)

    Hosokawa, Hideyuki; Uetake, Naoto; Hara, Teruo.

    1997-01-01

    Pipelines after decontamination of radioactive nuclides deposited on the pipelines in a nuclear power plant during operation or pipelines to replace pipelines deposited with radioactive nuclide are connected to each system of the nuclear power plant. They are heated in a gas phase containing oxygen to form an oxide film on the surface of the pipelines. The thickness of the oxide film formed in the gas phase is 1nm or greater, preferably 100nm. The concentration of oxygen in the gas phase containing oxygen must be 0.1% or greater. The heating is conducted by circulating a heated gas to the inside of the pipelines or disposing a movable heater such as a high frequency induction heater inside of the pipelines to form the oxide film. Then, redeposition of radioactive nuclide can be suppressed and since the oxide film is formed in the gas phase, a large scaled facilities are not necessary, thereby enabling to repair pipelines of reactor primary system at low cost. (N.H.)

  15. Capacitated two-echelon inventory models for repairable item systems

    NARCIS (Netherlands)

    Avsar, Z.M.; Zijm, Willem H.M.; Gershwin, S.B.; Dallery, Y.; Papadopoulos, C.; Smith, J.M.

    2002-01-01

    In this paper, we consider two-echelon maintenance systems with repair facilities both at a number of local service centers (called bases) and at a central location. Each repair facility may be considered to be a job shop and is modeled as a (limited capacity) open queuing network, while any

  16. Single-Molecule Methods for Nucleotide Excision Repair: Building a System to Watch Repair in Real Time.

    Science.gov (United States)

    Kong, Muwen; Beckwitt, Emily C; Springall, Luke; Kad, Neil M; Van Houten, Bennett

    2017-01-01

    Single-molecule approaches to solving biophysical problems are powerful tools that allow static and dynamic real-time observations of specific molecular interactions of interest in the absence of ensemble-averaging effects. Here, we provide detailed protocols for building an experimental system that employs atomic force microscopy and a single-molecule DNA tightrope assay based on oblique angle illumination fluorescence microscopy. Together with approaches for engineering site-specific lesions into DNA substrates, these complementary biophysical techniques are well suited for investigating protein-DNA interactions that involve target-specific DNA-binding proteins, such as those engaged in a variety of DNA repair pathways. In this chapter, we demonstrate the utility of the platform by applying these techniques in the studies of proteins participating in nucleotide excision repair. © 2017 Elsevier Inc. All rights reserved.

  17. Association of thymine glycol lesioned DNA with repair enzyme endonuclease III-molecular dynamics study

    International Nuclear Information System (INIS)

    Pinak, Miroslav

    2001-07-01

    The 2 nanoseconds molecular dynamics (MD) simulation has been performed for the system consisting of repair enzyme and DNA 30-mer with native thymine at position 16 replaced by thymine glycol (TG) solvated in water environment. After 950 picoseconds of MD the enzyme and DNA associated together to form complex that lasted stable up to 2 ns when simulation was terminated. At the contact area of enzyme and DNA there is glutamic acid located as close as 1.6 A to the C3' atom of phosphodiester bond of TG. Initial B-DNA molecule was bent and kinked at the TG during MD. This distortion caused that phosphodiester bond was easier accessible by amino acids of enzyme. The negative value of electrostatic energy (-26 kcal/mol) discriminates TG from nearly neutral native thymine and contributes to the specific recognition of this lesion. Higher number of close water molecules at TG site before formation of complex (compared with other nucleotides) indicates that glycosyl bond of the lesion is easily approached by repair enzyme during scanning of DNA surface and suggests the importance of specific hydration at the lesion during recognition process. (author)

  18. Association of thymine glycol lesioned DNA with repair enzyme endonuclease III-molecular dynamics study

    Energy Technology Data Exchange (ETDEWEB)

    Pinak, Miroslav [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2001-07-01

    The 2 nanoseconds molecular dynamics (MD) simulation has been performed for the system consisting of repair enzyme and DNA 30-mer with native thymine at position 16 replaced by thymine glycol (TG) solvated in water environment. After 950 picoseconds of MD the enzyme and DNA associated together to form complex that lasted stable up to 2 ns when simulation was terminated. At the contact area of enzyme and DNA there is glutamic acid located as close as 1.6 A to the C3' atom of phosphodiester bond of TG. Initial B-DNA molecule was bent and kinked at the TG during MD. This distortion caused that phosphodiester bond was easier accessible by amino acids of enzyme. The negative value of electrostatic energy (-26 kcal/mol) discriminates TG from nearly neutral native thymine and contributes to the specific recognition of this lesion. Higher number of close water molecules at TG site before formation of complex (compared with other nucleotides) indicates that glycosyl bond of the lesion is easily approached by repair enzyme during scanning of DNA surface and suggests the importance of specific hydration at the lesion during recognition process. (author)

  19. Repair systems for deteriorated bridge piles : final report.

    Science.gov (United States)

    2017-04-01

    The objective of this research project is to develop a durable repair system for deteriorated steel bridge piles that : can be implemented without the need for dewatering. A rigorous survey of the relevant practice nationwide was : conducted to infor...

  20. Dacryoscintigraph evaluation of the repaired lacrimal drainage system

    International Nuclear Information System (INIS)

    Hoehn, J.G.; Vitale, P.; Elliott, R.A. Jr.

    1976-01-01

    We have used dacryoscintigraphy to study the efficiency of the lacrimal system following the repair of a divided lower canaliculus in 4 children. This test has been reliable in evaluating lacrimal function and suggests that a canaliculus can be repaired and splinted satisfactorily. Our experience with dacryoscintigraphy confirms that it is a safe comfortable, and reliable method for studying the patency of the lacrimal drainage system

  1. [Studies on the repair of damaged DNA in bacteriophage, bacterial and mammalian systems]: Final report

    International Nuclear Information System (INIS)

    Friedberg, E.C.

    1987-08-01

    This study sought to exploit the use of uv radiation as a source of genomic damage. We explored the molecular mechanism of the repair of DNA damage at a number of different levels of biological organization, by investigating bacteriophage, bacterial, yeast and mammalian cells. Not only have observations obtained in one biological system suggested specific experimental approaches in others, but we have also learned that some biochemical pathways for DNA repair are unique to specific organisms. Our studies are summarized in terms of 4 major areas of research activity that span the past 16 years. 86 refs

  2. Web-ADARE: A Web-Aided Data Repairing System

    KAUST Repository

    Gu, Binbin

    2017-03-08

    Data repairing aims at discovering and correcting erroneous data in databases. In this paper, we develop Web-ADARE, an end-to-end web-aided data repairing system, to provide a feasible way to involve the vast data sources on the Web in data repairing. Our main attention in developing Web-ADARE is paid on the interaction problem between web-aided repairing and rule-based repairing, in order to minimize the Web consultation cost while reaching predefined quality requirements. The same interaction problem also exists in crowd-based methods but this is not yet formally defined and addressed. We first prove in theory that the optimal interaction scheme is not feasible to be achieved, and then propose an algorithm to identify a scheme for efficient interaction by investigating the inconsistencies and the dependencies between values in the repairing process. Extensive experiments on three data collections demonstrate the high repairing precision and recall of Web-ADARE, and the efficiency of the generated interaction scheme over several baseline ones.

  3. Web-ADARE: A Web-Aided Data Repairing System

    KAUST Repository

    Gu, Binbin; Li, Zhixu; Yang, Qiang; Xie, Qing; Liu, An; Liu, Guanfeng; Zheng, Kai; Zhang, Xiangliang

    2017-01-01

    Data repairing aims at discovering and correcting erroneous data in databases. In this paper, we develop Web-ADARE, an end-to-end web-aided data repairing system, to provide a feasible way to involve the vast data sources on the Web in data repairing. Our main attention in developing Web-ADARE is paid on the interaction problem between web-aided repairing and rule-based repairing, in order to minimize the Web consultation cost while reaching predefined quality requirements. The same interaction problem also exists in crowd-based methods but this is not yet formally defined and addressed. We first prove in theory that the optimal interaction scheme is not feasible to be achieved, and then propose an algorithm to identify a scheme for efficient interaction by investigating the inconsistencies and the dependencies between values in the repairing process. Extensive experiments on three data collections demonstrate the high repairing precision and recall of Web-ADARE, and the efficiency of the generated interaction scheme over several baseline ones.

  4. A bivariate optimal replacement policy for a multistate repairable system

    International Nuclear Information System (INIS)

    Zhang Yuanlin; Yam, Richard C.M.; Zuo, Ming J.

    2007-01-01

    In this paper, a deteriorating simple repairable system with k+1 states, including k failure states and one working state, is studied. It is assumed that the system after repair is not 'as good as new' and the deterioration of the system is stochastic. We consider a bivariate replacement policy, denoted by (T,N), in which the system is replaced when its working age has reached T or the number of failures it has experienced has reached N, whichever occurs first. The objective is to determine the optimal replacement policy (T,N)* such that the long-run expected profit per unit time is maximized. The explicit expression of the long-run expected profit per unit time is derived and the corresponding optimal replacement policy can be determined analytically or numerically. We prove that the optimal policy (T,N)* is better than the optimal policy N* for a multistate simple repairable system. We also show that a general monotone process model for a multistate simple repairable system is equivalent to a geometric process model for a two-state simple repairable system in the sense that they have the same structure for the long-run expected profit (or cost) per unit time and the same optimal policy. Finally, a numerical example is given to illustrate the theoretical results

  5. Biochemical studies of DNA strand break repair and molecular characterization of mei-41, a gene involved in DNA break repair

    International Nuclear Information System (INIS)

    Oliveri, D.R.

    1989-01-01

    The ability to repair X-irradiation induced single-strand DNA breaks was examined in mutagen-sensitive mutants of Drosophila melanogaster. This analysis demonstrated that examined stocks possess a normal capacity to repair X-ray induced single-strand breaks. One of the mutants in this study, mei-41, has been shown to be involved in a number of DNA metabolizing functions. A molecular characterization of this mutant is presented. A cDNA hybridizing to genomic DNA both proximal and distal to a P element inducing a mei-41 mutation was isolated from both embryonic and adult female recombinant lambda phage libraries. A 2.2 kilobase embryonic cDNA clone was sequenced; the sequence of an open reading frame was identified which would predict a protein of 384 amino acids with a molecular weight of 43,132 daltons. An examination of homologies to sequences in protein and nucleic acid data bases revealed no sequences with significant homology to mei-41, however, two potential Zinc-finger domains were identified. Analysis of RNA hybridizing to the embryonic cDNA demonstrated the existence of a major 2.2 kilobase transcript expressed primarily in embryos and adult flies. An examination of the transcription of this gene in mei-41 mutants revealed significant variation from wild-type, an indication that the embryonic cDNA does represent a mei-41 transcript. Expression in tissues from adult animals demonstrated that the 2.2 kilobase RNA is expressed primarily in reproductive tissues. A 3.8kb transcript is the major species of RNA in the adult head and thorax. Evidence is presented which implies that expression of the mei-41 gene is strongly induced by exposure of certain cells to mutagens

  6. ADHESIVE SYSTEM AFFECTS REPAIR BOND STRENGTH OF RESIN COMPOSITE

    Directory of Open Access Journals (Sweden)

    Özgür IRMAK

    2017-10-01

    Full Text Available Purpose: This study evaluated the effects of different adhesive systems on repair bond strength of aged resin composites. Materials and Methods: Ninety composite discs were built and half of them were subjected to thermal aging. Aged and non-aged specimens were repaired with resin composite using three different adhesive systems; a two-step self-etch adhesive, a two-step total-etch adhesive and a one-step self-etch adhesive; then they were subjected to shear forces. Data were analyzed statistically. Results: Adhesive type and aging significantly affected the repair bond strengths (p<0.0001. No statistical difference was found in aged composite groups repaired with two-step self- etch or two-step total-etch adhesive. One-step self-etch adhesive showed lower bond strength values in aged composite repair (p<0.0001. Conclusion: In the repair of aged resin composite, two-step self-etch and two-step total-etch adhesives exhibited higher shear bond strength values than that of one-step self-etch adhesive.

  7. Cold standby repairable system with working vacations and vacation interruption

    Institute of Scientific and Technical Information of China (English)

    Baoliang Liu; Lirong Cui; Yanqing Wen

    2015-01-01

    This paper studies a cold standby repairable system with working vacations and vacation interruption. The repairman’s multiple vacations policy, the working vacations policy and the vacation interruption are considered simultaneously. The lifetime of components fol ows a phase-type (PH) distribution. The repair time in the regular repair period and the working vacation period fol ow other two PH distributions at different rates. For this sys-tem, the vector-valued Markov process governing the system is constructed. We obtain several important performance measures for the system in transient and stationary regimes applying matrix-analytic methods. Final y, a numerical example is given to il ustrate the results obtained.

  8. Molecular characteristics of mismatch repair genes in sporadic colorectal tumors in Czech patients

    Czech Academy of Sciences Publication Activity Database

    Vymetálková, Veronika; Slyšková, Jana; Korenková, Vlasta; Bielik, Ludovít; Langerová, Lucie; Procházka, Pavel; Rejhová, Alexandra; Schwarzová, L.; Pardini, B.; Naccarati, Alessio; Vodička, Pavel

    2014-01-01

    Roč. 15, č. 1 (2014), s. 17 ISSN 1471-2350 R&D Projects: GA AV ČR IAA500200917; GA ČR(CZ) GPP304/11/P715 Grant - others:GA MŠk(CZ) Prvouk-P27/LF1/1 Institutional support: RVO:68378041 ; RVO:86652036 Keywords : colorectal cancer * mismatch repair genes * expression levels Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 2.083, year: 2014

  9. Inducible DNA-repair systems in yeast: competition for lesions.

    Science.gov (United States)

    Mitchel, R E; Morrison, D P

    1987-03-01

    DNA lesions may be recognized and repaired by more than one DNA-repair process. If two repair systems with different error frequencies have overlapping lesion specificity and one or both is inducible, the resulting variable competition for the lesions can change the biological consequences of these lesions. This concept was demonstrated by observing mutation in yeast cells (Saccharomyces cerevisiae) exposed to combinations of mutagens under conditions which influenced the induction of error-free recombinational repair or error-prone repair. Total mutation frequency was reduced in a manner proportional to the dose of 60Co-gamma- or 254 nm UV radiation delivered prior to or subsequent to an MNNG exposure. Suppression was greater per unit radiation dose in cells gamma-irradiated in O2 as compared to N2. A rad3 (excision-repair) mutant gave results similar to wild-type but mutation in a rad52 (rec-) mutant exposed to MNNG was not suppressed by radiation. Protein-synthesis inhibition with heat shock or cycloheximide indicated that it was the mutation due to MNNG and not that due to radiation which had changed. These results indicate that MNNG lesions are recognized by both the recombinational repair system and the inducible error-prone system, but that gamma-radiation induction of error-free recombinational repair resulted in increased competition for the lesions, thereby reducing mutation. Similarly, gamma-radiation exposure resulted in a radiation dose-dependent reduction in mutation due to MNU, EMS, ENU and 8-MOP + UVA, but no reduction in mutation due to MMS. These results suggest that the number of mutational MMS lesions recognizable by the recombinational repair system must be very small relative to those produced by the other agents. MNNG induction of the inducible error-prone systems however, did not alter mutation frequencies due to ENU or MMS exposure but, in contrast to radiation, increased the mutagenic effectiveness of EMS. These experiments demonstrate

  10. Service water system repair/replacement guidelines: Planning and implementation

    International Nuclear Information System (INIS)

    Frederick, G.J.; Gandy, D.W.; Peterson, A.G. Jr.; Findlan, S.J.

    1993-11-01

    Service water system failures have prompted concerns related to extended power plant operating life and plant availability. Selection and procurement of materials for repair or replacement of piping and components may be the most important factors in improving service water system reliability. The authors examined factors that contribute to reduced SWS reliability. The factors include material selection inadequacies, water treatment problems, operational/maintenance practices, fabrication procedures, environmental degradation mechanisms, and coating problems. The authors investigated material selection for replacement and repair, taking into account fabrication practices, environmental concerns, and cost comparisons of materials. They examined specific components such as piping, pumps, valves, and heat exchangers with regard to material selection and fabrication practice. Although proper material selection is essential in upgrading and maintaining the designed functions of a SWS, it is critical to address SWS repair/replacement activities with a systemwide approach. Degradation of materials in SWS applications are plant specific, depending on factors unique to each site such as geographic location, existing materials, operating procedures, and environment. All these characteristics must be addressed in making repair/replacement decisions. Criteria that must be integrated for successful long-term operation of SWS include the following: Materials selection (upgrade or in-kind replacement), Evaluation of root cause or nature of the failure mechanism, Scope of the repair/replacement activities, Material compatibility of the existing materials, Operational and maintenance procedures, Code or jurisdictional requirements, Economic considerations, Water treatment programs, System design improvements or modifications

  11. Balancing flexibility and inventory in repair inventory systems

    NARCIS (Netherlands)

    Haas, de H.F.M.; Martin, H.H.

    1995-01-01

    In repair inventory systems, failed units are exchanged for serviceable units upon failure. The probability that serviceable units are available to support the exchange process can be used as a measure for the performance of the system. This measure is commonly called the expected fill rate. The

  12. Effective Measurement of Reliability of Repairable USAF Systems

    Science.gov (United States)

    2012-09-01

    ix I. Introduction ...RELIABILITY OF REPAIRABLE USAF SYSTEMS I. Introduction General Issue The United States relies on complex systems to protect and project the national...Under Secretary of Defense for Acquisition, Technology, and Logistics, Implementing a Lifecycle Mangement Framework, Washington DC, DC: DoD, 2008

  13. Closed loop two-echelon repairable item systems

    NARCIS (Netherlands)

    Spanjers, L.; van Ommeren, Jan C.W.; Zijm, Willem H.M.; Liberopoulos, G.; Papadopoulos, C.T.; Tan, B.; MacGregor Smith, J.; Gershwin, S.B.

    2006-01-01

    In this paper we consider closed loop two-echelon epairable item systems with repair facilities both at a number of local service centers (called bases) and at a central location (the depot). The goal of the system is to maintain a number of production facilities (one at each base) in optimal

  14. Mountain Plains Learning Experience Guide: Automotive Repair. Course: Emission Systems.

    Science.gov (United States)

    Schramm, C.; Osland, Walt

    One of twelve individualized courses included in an automotive repair curriculum, this course covers the theory, testing, and servicing of automotive emission control systems. The course is comprised of one unit, Fundamentals of Emission Systems. The unit begins with a Unit Learning Experience Guide that gives directions for unit completion. The…

  15. Biomechanical testing of new meniscal repair techniques containing ultra high-molecular weight polyethylene suture.

    Science.gov (United States)

    Barber, F Alan; Herbert, Morley A; Schroeder, F Alexander; Aziz-Jacobo, Jorge; Sutker, Michael J

    2009-09-01

    To evaluate the biomechanical characteristics of current meniscal repair techniques containing ultra high-molecular weight polyethylene (UHMWPE) suture with and without cyclic loading. Vertical longitudinal cuts made in porcine menisci were secured with a single repair device. Noncycled and cycled (500 cycles) biomechanical tests were performed on the following groups: group 1, No. 2-0 Mersilene vertical suture (Ethicon, Somerville, NJ); group 2, No. 2-0 Orthocord vertical suture (DePuy Mitek, Westwood, MA); group 3, No. 0 Ultrabraid vertical suture (Smith & Nephew Endoscopy, Andover, MA); group 4, No. 2-0 FiberWire vertical suture (Arthrex, Naples, FL); group 5, vertically oriented mattress suture by use of an Ultra FasT-Fix device (Smith & Nephew Endoscopy) with No. 0 Ultrabraid; group 6, vertically oriented mattress suture by use of a RapidLoc A2 device (DePuy Mitek) with No. 2-0 Orthocord suture; group 7, vertically oriented stitch by use of a MaxFire device with MaxBraid PE suture (Biomet Sports Medicine, Warsaw, IN); and group 8, an obliquely oriented stitch of No. 0 UHMWPE suture inserted by use of a CrossFix device (Cayenne Medical, Scottsdale, AZ). Endpoints were failure loads, failure modes, stiffness, and cyclic displacement. Mean single-pull loads were calculated for Ultra FasT-Fix (121 N), FiberWire (110 N), MaxFire (130 N), Mersilene (84 N), Orthocord (124 N), RapidLoc A2 (86 N), CrossFix (77 N), and Ultrabraid (109 N). After 500 cyclic loads, the Orthocord (222 N) repair was stronger than the others: Ultra FasT-Fix (110 N), FiberWire (117 N), MaxFire (132 N), Mersilene (89 N), RapidLoc A2 (108 N), CrossFix (95 N), and Ultrabraid (126 N) (P Fix, RapidLoc A2, and MaxFire) were comparable to the isolated UHMWPE-containing suture repairs on single-failure load testing. UHMWPE-containing suture repairs are stronger than braided polyester suture repairs, but pure UHMWPE suture (Ultrabraid) elongated more during cycling. Orthocord suture is significantly

  16. Iterative Repair Planning for Spacecraft Operations Using the Aspen System

    Science.gov (United States)

    Rabideau, G.; Knight, R.; Chien, S.; Fukunaga, A.; Govindjee, A.

    2000-01-01

    This paper describes the Automated Scheduling and Planning Environment (ASPEN). ASPEN encodes complex spacecraft knowledge of operability constraints, flight rules, spacecraft hardware, science experiments and operations procedures to allow for automated generation of low level spacecraft sequences. Using a technique called iterative repair, ASPEN classifies constraint violations (i.e., conflicts) and attempts to repair each by performing a planning or scheduling operation. It must reason about which conflict to resolve first and what repair method to try for the given conflict. ASPEN is currently being utilized in the development of automated planner/scheduler systems for several spacecraft, including the UFO-1 naval communications satellite and the Citizen Explorer (CX1) satellite, as well as for planetary rover operations and antenna ground systems automation. This paper focuses on the algorithm and search strategies employed by ASPEN to resolve spacecraft operations constraints, as well as the data structures for representing these constraints.

  17. Molecular dynamics simulations of deoxyribonucleic acids and repair enzyme T4 endonuclease V

    International Nuclear Information System (INIS)

    Pinak, Miroslav

    1999-01-01

    This report describes the results of molecular dynamics (MD) simulation of deoxyribonucleic acids (DNA) and specific repair enzyme T4 endonuclease V. Namely research described here is focused on the examination of specific recognition process, in which this repair enzyme recognizes the damaged site on the DNA molecule-thymine dimer (TD). TD is frequent DNA damage induced by UV radiation in sun light and unless properly repaired it may be mutagenic or lethal for cell, and is also considered among the major causes of skin cancer. T4 endonuclease V is a DNA specific repair enzyme from bacteriophage T4 that catalyzes the first reaction step of TD repair pathway. MD simulations of three molecules - native DNA dodecamer (12 base pairs), DNA of the same sequence of nucleotides as native one but with TD, and repair enzyme T4 endonuclease V - were performed for 1 ns individually for each molecule. Simulations were analyzed to determine the role of electrostatic interaction in the recognition process. It is found that electrostatic energies calculated for amino acids of the enzyme have positive values of around +15 kcal/mol. The electrostatic energy of TD site has negative value of approximately -9 kcal/mol, different from the nearly neutral value of the respective thymines site of the native DNA. The electrostatic interaction of TD site with surrounding water environment differs from the electrostatic interaction of other nucleotides. Differences found between TD site and respective thymines site of native DNA indicate that the electrostatic energy is an important factor contributing to proper recognition of TD site during scanning process in which enzyme scans the DNA. In addition to the electrostatic energy, the important factor in recognition process might be structural complementarity of enzyme and bent DNA with TD. There is significant kink formed around TD site, that is not observed in native DNA. (author)

  18. Molecular cloning and characterization of genes required for nucleotide excision repair in yeast

    International Nuclear Information System (INIS)

    Friedberg, E.C.

    1987-01-01

    Nucleotide excision repair in the yeast S. cerevisiae is a complex process which involves a large number of genes. At least five of these genes (RAD1, RAD2, RAD3, RAD4 and RAD10) are absolutely required for this process and mutations in any of these genes result in no detectable excision repair in vivo. In order to understand the function of these genes in DNA repair, the authors isolated a number of them by screening a yeast genomic library for recombinant plasmids which complement the phentoype of sensitivity to ultraviolet (UV) radiation imparted to mutant strains. A plasmid containing the RAD4 gene was isolated by an alternative strategy which will be discussed. The cloned genes have been extensively characterized. It has been determined that the RAD3 gene is essential for the viability of haploid yeast cells in the absence of DNA damage. The RAD2 gene is inducible by treatment of cells with a variety of DNA-damaging agents, including UV radiation and ionizing radiation. The RAD10 gene shares considerable amino acid sequence homology with a cloned gene involved in nucleotide excision repair in human cells. Yeast is a particularly versatile organism for studying gene function by molecular and genetic approaches and emphasis is placed on many of the techniques used in the present studies

  19. Repair of uv damaged DNA in systemic lupus erythematosus. [Mice

    Energy Technology Data Exchange (ETDEWEB)

    Beighlie, D J; Teplitz, R L

    1975-06-01

    The NZB NZW hybrid mouse is an animal model of human systemic lupus erythematosus (SLE). Two breeding schemes were devised using NZB, NZW, B/W, and CBA mice, which permit definitive decisions regarding genetic and/or viral origin of the disease. It is proposed that at least two factors must be involved: a genetic abnormality producing hyper-responsiveness to nucleic acid antigens, and a DNA repair defect which results in liberation of DNA and RNA when cells are lethally injured. Evidence is presented for a DNA repair deficit in human SLE lymphocytes following in vitro irradiation with ultraviolet (uv) light. Lymphocytes from adult New Zealand and control mice were found to lack normal amounts of endonuclease necessary for repairing uv damage.

  20. Availability, reliability and downtime of systems with repairable components

    DEFF Research Database (Denmark)

    Kiureghian, Armen Der; Ditlevsen, Ove Dalager; Song, J.

    2007-01-01

    Closed-form expressions are derived for the steady-state availability, mean rate of failure, mean duration of downtime and lower bound reliability of a general system with randomly and independently failing repairable components. Component failures are assumed to be homogeneous Poisson events in ...

  1. Molecular dynamics simulation studies of radiation damaged DNA. Molecules and repair enzymes

    International Nuclear Information System (INIS)

    Pinak, Miroslav

    2004-12-01

    Molecular dynamics (MD) studies on several radiation damages to DNA and their recognition by repair enzymes are introduced in order to describe the stepwise description of molecular process observed at radiation lesion sites. MD studies were performed on pyrimidine (thymine dimer, thymine glycol) and purine (8-oxoguanine) lesions using an MD simulation code AMBER 5.0. The force field was modified for each lesion. In all cases the significant structural changes in the DNA double helical structure were observed; a) the breaking of hydrogen bond network between complementary bases and resulting opening of the double helix (8-oxoguanine); b) the sharp bending of the DNA helix centered at the lesion site (thymine dimer, thymine glycol); and c) the flipping-out base on the strand complementary to the lesion (8-oxoguanine). These changes were related to the overall collapsing double helical structure around the lesion and might facilitate the docking of the repair enzyme into the DNA and formation of DNA-enzyme complex. In addition to the structural changes, at lesion sites there were found electrostatic interaction energy values different from those at native sites (thymine dimer -10 kcal/mol, thymine glycol -26 kcal/mol, 8-oxoguanine -48 kcal/mol). These values of electrostatic energy may discriminate lesion from values at native sites (thymine 0 kcal/mol, guanine -37 kcal/mol) and enable a repair enzyme to recognize a lesion during scanning DNA surface. The observed specific structural conformation and energetic properties at the lesions sites are factors that guide a repair enzyme to discriminate lesions from non-damaged native DNA segments. (author)

  2. DNA Damage Repair System in Plants: A Worldwide Research Update.

    Science.gov (United States)

    Gimenez, Estela; Manzano-Agugliaro, Francisco

    2017-10-30

    Living organisms are usually exposed to various DNA damaging agents so the mechanisms to detect and repair diverse DNA lesions have developed in all organisms with the result of maintaining genome integrity. Defects in DNA repair machinery contribute to cancer, certain diseases, and aging. Therefore, conserving the genomic sequence in organisms is key for the perpetuation of life. The machinery of DNA damage repair (DDR) in prokaryotes and eukaryotes is similar. Plants also share mechanisms for DNA repair with animals, although they differ in other important details. Plants have, surprisingly, been less investigated than other living organisms in this context, despite the fact that numerous lethal mutations in animals are viable in plants. In this manuscript, a worldwide bibliometric analysis of DDR systems and DDR research in plants was made. A comparison between both subjects was accomplished. The bibliometric analyses prove that the first study about DDR systems in plants (1987) was published thirteen years later than that for other living organisms (1975). Despite the increase in the number of papers about DDR mechanisms in plants in recent decades, nowadays the number of articles published each year about DDR systems in plants only represents 10% of the total number of articles about DDR. The DDR research field was done by 74 countries while the number of countries involved in the DDR & Plant field is 44. This indicates the great influence that DDR research in the plant field currently has, worldwide. As expected, the percentage of studies published about DDR systems in plants has increased in the subject area of agricultural and biological sciences and has diminished in medicine with respect to DDR studies in other living organisms. In short, bibliometric results highlight the current interest in DDR research in plants among DDR studies and can open new perspectives in the research field of DNA damage repair.

  3. Molecular Alterations Associated with DNA Repair in Pancreatic Adenocarcinoma Are Associated with Sites of Recurrence.

    Science.gov (United States)

    Ferguson, Margaret D; Dong, Lei; Wan, Jim; Deneve, Jeremiah L; Dickson, Paxton V; Behrman, Stephen W; Shibata, David; Martin, Mike G; Glazer, Evan S

    2018-02-10

    Pancreatic ductal adenocarcinoma (PDAC) remains one of the deadliest malignancies with a rising incidence. Mutational analysis of PDAC has provided valuable information but has not yet dramatically changed the therapeutic landscape due to the number of variations detected in any one individual. The pattern of molecular alterations-gene mutations, variations in copy number, and changes in gene expression-has been described in the literature. The purpose of this study is to further investigate the molecular alterations in recurrent or metastatic PDAC based on the site of disease. Molecular alterations in patients with recurrent or metastatic PDAC from 2007 to 2015 were analyzed. The most common molecular alterations found in PDAC tumors from the pancreas were compared to metastatic PDAC specimens from the liver, lung, peritoneum, and other locations. Means were compared with a two-tailed Student's t test or ANOVA as appropriate. Rates of molecular alterations among the different groups were compared with Pearson's χ 2 . Two thousand five hundred fifty-two patients with PDAC were identified in a retrospective database, and the 15 most common molecular alterations were utilized for analysis. The most common alterations among all patients were mutations in KRAS and PTEN (59 and 62%, respectively), with differences in prevalence by site of metastasis (p = 0.042 and p = 0.037, respectively). KRAS mutations were more commonly found in metastasis in the lung (72%) than in other sites (59%, p = 0.042). Low expression of ERCC1 was found in 49% of lung metastases from PDAC but only 15% in PDAC in the pancreas (p molecular alterations significantly associated with site of metastatic disease were involved in DNA maintenance, repair, replication, or transcription (each p molecular alterations warrants further investigation.

  4. Optimal Inspection and Repair Strategies for Structural Systems

    DEFF Research Database (Denmark)

    Sommer, A. M.; Nowak, A. S.; Thoft-Christensen, Palle

    1992-01-01

    and a design variable as optimization variables. A model for estimating the total expected costs for structural systems is given including the costs associated with the loss of individual structural members as well as the costs associated with the loss of at least one element of a particular group......A model for reliability-based repair and maintenance strategies of structural systems is described. The total expected costs in the lifetime of the structure are minimized with the number of inspections, the number and positions of the inspected points, the inspection efforts, the repair criteria...... of structural members and the costs associated with the simultaneous loss of all members of a specific group of structural members. The approach is based on the pre-posteriori analysis from the classical decision theory. Special emphasis is given to the problem of selecting the number of points in the structure...

  5. Development of management system for plant repairing work

    International Nuclear Information System (INIS)

    Terauchi, Makoto

    1999-01-01

    In the fast breeder reactor, ''Monju'', in order to conduct nuclear plant repairing works securely and effectively, development of a computer system to assist management business on plant repairing work was begun on 1993. The system has been applied to about 5,000 times of operational management through past four times of plant inspection and to daily inspections and maintenance, and is daily used at working places of ''Monju'' such as issue/management of about 110,000 times of operational prohibition tag in isolated management. And, by automation of issue/management on working sheets and operational prohibition tag and others conducted hitherto by hand, the management business has been largely rationalized. (G.K.)

  6. Genomic and Molecular Landscape of DNA Damage Repair Deficiency across The Cancer Genome Atlas

    Directory of Open Access Journals (Sweden)

    Theo A. Knijnenburg

    2018-04-01

    Full Text Available Summary: DNA damage repair (DDR pathways modulate cancer risk, progression, and therapeutic response. We systematically analyzed somatic alterations to provide a comprehensive view of DDR deficiency across 33 cancer types. Mutations with accompanying loss of heterozygosity were observed in over 1/3 of DDR genes, including TP53 and BRCA1/2. Other prevalent alterations included epigenetic silencing of the direct repair genes EXO5, MGMT, and ALKBH3 in ∼20% of samples. Homologous recombination deficiency (HRD was present at varying frequency in many cancer types, most notably ovarian cancer. However, in contrast to ovarian cancer, HRD was associated with worse outcomes in several other cancers. Protein structure-based analyses allowed us to predict functional consequences of rare, recurrent DDR mutations. A new machine-learning-based classifier developed from gene expression data allowed us to identify alterations that phenocopy deleterious TP53 mutations. These frequent DDR gene alterations in many human cancers have functional consequences that may determine cancer progression and guide therapy. : Knijnenburg et al. present The Cancer Genome Atlas (TCGA Pan-Cancer analysis of DNA damage repair (DDR deficiency in cancer. They use integrative genomic and molecular analyses to identify frequent DDR alterations across 33 cancer types, correlate gene- and pathway-level alterations with genome-wide measures of genome instability and impaired function, and demonstrate the prognostic utility of DDR deficiency scores. Keywords: The Cancer Genome Atlas PanCanAtlas project, DNA damage repair, somatic mutations, somatic copy-number alterations, epigenetic silencing, DNA damage footprints, mutational signatures, integrative statistical analysis, protein structure analysis

  7. On some steady-state characteristics of systems with gradual repair

    International Nuclear Information System (INIS)

    Finkelstein, Maxim; Ludick, Zani

    2014-01-01

    We consider a repairable system with continuous output that alternates between states of operation and repair. The output of the system in the operating state is represented by a continuous, decreasing function of time. We assume that during the repair state, the system can produce output that is modelled by an increasing stochastic process. The repair action gradually restores the output of the system to its initial level and it returns to the operating state. We obtain and analyse expressions for the generalized availability and related characteristics of systems with gradual repair and consider several meaningful examples

  8. Moisture movement in cement-based repair systems monitored by X-ray absorption

    NARCIS (Netherlands)

    Lukovic, M.; Ye, G.; Schlangen, H.E.J.G.; van Breugel, K.

    2017-01-01

    In concrete repair systems, material properties in the repair material and interface are greatly influenced by the initial moisture content of the concrete (or mortar) substrate. In order to quantify moisture profiles inside the repair system, X-ray absorption was used. Preliminary studies are

  9. The development of a remote repair system for deep water pipelines

    Energy Technology Data Exchange (ETDEWEB)

    Frazer, Ian; Giles, John [Stolt Offshore MS Ltd., Aberdeen (United Kingdom)

    2000-07-01

    The ability to maintain a high level of flexibility within the contingency plans for sub sea pipeline repair is a critical issue normally achieved by basing the repair plans on diver intervention. This allows the pipeline operator flexibility to respond to particular repair situations as they occur, minimize up front planning and optimize the investment in repair equipment and stock. However for deep water pipelines all intervention must be performed by remote methods, which require the development of suitable equipment and more detailed repair procedures. This paper describes the development of a remotely operated pipeline repair system capable of working down to 3000 m and allowing a relatively high level of flexibility with minimum investment in repair stock. The repair system is based upon the Modular Advanced Tie-In System (MATIS) which has been successfully developed for the tie-in of deep water flow lines. The MATIS repair system is based on the use of standard flanges to replace a damaged section of pipe with a spool piece in a similar manner to a hyperbaric welded repair. Various repair scenarios are discussed in the paper together with the equipment and the procedures used to perform the repair. The paper will also discuss the other remote repair options such as hot tapping and friction stitch welding. (author)

  10. Reliable pipeline repair system for very large pipe size

    Energy Technology Data Exchange (ETDEWEB)

    Charalambides, John N.; Sousa, Alexandre Barreto de [Oceaneering International, Inc., Houston, TX (United States)

    2004-07-01

    The oil and gas industry worldwide has been mainly depending on the long-term reliability of rigid pipelines to ensure the transportation of hydrocarbons, crude oil, gas, fuel, etc. Many other methods are also utilized onshore and offshore (e.g. flexible lines, FPSO's, etc.), but when it comes to the underwater transportation of very high volumes of oil and gas, the industry commonly uses large size rigid pipelines (i.e. steel pipes). Oil and gas operators learned to depend on the long-lasting integrity of these very large pipelines and many times they forget or disregard that even steel pipelines degrade over time and more often that that, they are also susceptible to various forms of damage (minor or major, environmental or external, etc.). Over the recent years the industry had recognized the need of implementing an 'emergency repair plan' to account for such unforeseen events and the oil and gas operators have become 'smarter' by being 'pro-active' in order to ensure 'flow assurance'. When we consider very large diameter steel pipelines such as 42' and 48' nominal pipe size (NPS), the industry worldwide does not provide 'ready-made', 'off-the-shelf' repair hardware that can be easily shipped to the offshore location and effect a major repair within acceptable time frames and avoid substantial profit losses due to 'down-time' in production. The typical time required to establish a solid repair system for large pipe diameters could be as long as six or more months (depending on the availability of raw materials). This paper will present in detail the Emergency Pipeline Repair Systems (EPRS) that Oceaneering successfully designed, manufactured, tested and provided to two major oil and gas operators, located in two different continents (Gulf of Mexico, U.S.A. and Arabian Gulf, U.A.E.), for two different very large pipe sizes (42'' and 48'' Nominal Pipe Sizes

  11. DNA repair

    International Nuclear Information System (INIS)

    Setlow, R.

    1978-01-01

    Some topics discussed are as follows: difficulty in extrapolating data from E. coli to mammalian systems; mutations caused by UV-induced changes in DNA; mutants deficient in excision repair; other postreplication mechanisms; kinds of excision repair systems; detection of repair by biochemical or biophysical means; human mutants deficient in repair; mutagenic effects of UV on XP cells; and detection of UV-repair defects among XP individuals

  12. Availability estimation of repairable systems using reliability graph with general gates (RGGG)

    International Nuclear Information System (INIS)

    Goh, Gyoung Tae

    2009-02-01

    By performing risk analysis, we may obtain sufficient information about the system to redesign it and lower the probability of the occurrence of an accident or mitigate the ensuing consequences. The concept of reliability is widely used to express risk of systems. The reliability is used for non-repairable systems. But nuclear power plant systems are repairable systems. With repairable systems, repairable components can improve the availability of a system because faults that are generated in components can be recovered. Hence, the availability of the system is more proper concept in case of repairable systems. Reliability graph with general gate (RGGG) is one of the system reliability analysis methods. The RGGG is a very intuitiveness method as compared with other methods. But the RGGG has not been applied to repairable systems yet. The objective of this study is to extend the RGGG in order to enable one to analyze repairable system. Determining the probability table for each node is a critical process to calculate the system availability in the RGGG method. Therefore finding the proper algorithms and making probability tables in various situations are the major a part of this study. The other part is an example of applying RGGG method to a real system. We find the proper algorithms and probability tables for independent repairable systems, dependent series repairable systems, and k-out-of-m (K/M) redundant parallel repairable systems in this study. We can evaluate the availability of real system using these probability tables. An example for a real system is shown in the latter part of this study. For the purpose of this analysis, the charging pumps subsystem of the chemical and volume control system (CVCS) was selected. The RGGG method extended for repairable systems has the same characteristic of intuitiveness as the original RGGG method and we can confirm that the availability analysis result from the repairable RGGG method is exact

  13. Molecular targets, DNA breakage, DNA repair: Their roles in mutation induction in mammalian germ cells

    International Nuclear Information System (INIS)

    Sega, G.A.

    1989-01-01

    Variability in genetic sensitivity among different germ-cell stages in the mammal to various mutagens could be the result of how much chemical reaches the different stages, what molecular targets may be affected in the different stages and whether or not repair of lesions occurs. Several chemicals have been found to bind very strongly to protamine in late-spermatid and early-spermatozoa stages in the mouse. The chemicals also produce their greatest genetic damage in these same germ-cell stages. While chemical binding to DNA has not been correlated with the level of induced genetic damage, DNA breakage in the sensitive stages has been shown to increase. This DNA breakage is believed to indirectly result from chemical binding to sulfhydryl groups in protamine which prevents normal chromatin condensation within the sperm nucleus. 22 refs., 5 figs

  14. Actualities on molecular pathogenesis and repairing processes of cerebral damage in perinatal hypoxic-ischemic encephalopathy

    Directory of Open Access Journals (Sweden)

    Praticò Andrea D

    2010-09-01

    Full Text Available Abstract Hypoxic-ischemic encephalopathy (HIE is the most important cause of cerebral damage and long-term neurological sequelae in the perinatal period both in term and preterm infant. Hypoxic-ischemic (H-I injuries develop in two phases: the ischemic phase, dominated by necrotic processes, and the reperfusion phase, dominated by apoptotic processes extending beyond ischemic areas. Due to selective ischemic vulnerability, cerebral damage affects gray matter in term newborns and white matter in preterm newborns with the typical neuropathological aspects of laminar cortical necrosis in the former and periventricular leukomalacia in the latter. This article summarises the principal physiopathological and biochemical processes leading to necrosis and/or apoptosis of neuronal and glial cells and reports recent insights into some endogenous and exogenous cellular and molecular mechanisms aimed at repairing H-I cerebral damage.

  15. Molecular phenotyping of human ovarian cancer stem cells unravels the mechanisms for repair and chemoresistance

    DEFF Research Database (Denmark)

    Alvero, Ayesha B; Chen, Rui; Fu, Han-Hsuan

    2009-01-01

    A major burden in the treatment of ovarian cancer is the high percentage of recurrence and chemoresistance. Cancer stem cells (CSCs) provide a reservoir of cells that can self-renew, can maintain the tumor by generating differentiated cells [non-stem cells (non-CSCs)] which make up the bulk...... to form spheroids in suspension, and the ability to recapitulate in vivo the original tumor. Chemotherapy eliminates the bulk of the tumor but it leaves a core of cancer cells with high capacity for repair and renewal. The molecular properties identified in these cells may explain some of the unique...... of the tumor and may be the primary source of recurrence. We describe the characterization of human ovarian cancer stem cells (OCSCs). These cells have a distinctive genetic profile that confers them with the capacity to recapitulate the original tumor, proliferate with chemotherapy, and promote recurrence...

  16. Reliability analysis for a circular consecutive-2-out-of-n:F repairable system with priority in repair

    International Nuclear Information System (INIS)

    Zhang Yuanlin; Zuo, Ming J.; Yam, Richard C.M.

    2000-01-01

    A circular consecutive-2-out-of-n:F repairable system with one repairman is studied in this paper. When there are more than one failed component, priorities are assigned to the failed components. Both the working time and the repair time of each component is assumed to be exponentially distributed. Every component after repair is as good as new. By using the definition of generalized transition probability and the concept of critical component, we derive the state transition probability matrix of the system. Methodologies are then presented for the derivation of system reliability indexes such as availability, rate of occurrence of failure, mean time between failures, reliability, and mean time to first failure

  17. Role of the immune system in cardiac tissue damage and repair following myocardial infarction.

    Science.gov (United States)

    Saparov, Arman; Ogay, Vyacheslav; Nurgozhin, Talgat; Chen, William C W; Mansurov, Nurlan; Issabekova, Assel; Zhakupova, Jamilya

    2017-09-01

    The immune system plays a crucial role in the initiation, development, and resolution of inflammation following myocardial infarction (MI). The lack of oxygen and nutrients causes the death of cardiomyocytes and leads to the exposure of danger-associated molecular patterns that are recognized by the immune system to initiate inflammation. At the initial stage of post-MI inflammation, the immune system further damages cardiac tissue to clear cell debris. The excessive production of reactive oxygen species (ROS) by immune cells and the inability of the anti-oxidant system to neutralize ROS cause oxidative stress that further aggravates inflammation. On the other hand, the cells of both innate and adaptive immune system and their secreted factors are critically instrumental in the very dynamic and complex processes of regulating inflammation and mediating cardiac repair. It is important to decipher the balance between detrimental and beneficial effects of the immune system in MI. This enables us to identify better therapeutic targets for reducing the infarct size, sustaining the cardiac function, and minimizing the likelihood of heart failure. This review discusses the role of both innate and adaptive immune systems in cardiac tissue damage and repair in experimental models of MI.

  18. An antilock molecular braking system.

    Science.gov (United States)

    Sun, Wei-Ting; Huang, Shou-Ling; Yao, Hsuan-Hsiao; Chen, I-Chia; Lin, Ying-Chih; Yang, Jye-Shane

    2012-08-17

    A light-driven molecular brake displaying an antilock function is constructed by introducing a nonradiative photoinduced electron transfer (PET) decay channel to compete with the trans (brake-off) → cis (brake-on) photoisomerization. A fast release of the brake can be achieved by deactivating the PET process through addition of protons. The cycle of irradiation-protonation-irradiation-deprotonation conducts the brake function and mimics the antilock braking system (ABS) of vehicles.

  19. Direct Self-Repairing Control for Quadrotor Helicopter Attitude Systems

    Directory of Open Access Journals (Sweden)

    Huiliao Yang

    2014-01-01

    Full Text Available A quadrotor helicopter with uncertain actuator faults, such as loss of effectiveness and lock-in-place, is studied in this paper. An adaptive fuzzy sliding mode controller based on direct self-repairing control is designed for such nonlinear system to track the desired output signal, when any actuator of this quadrotor helicopter is loss of effectiveness or stuck at some place. Moreover, using the Lyapunov stability theory, the stability of the whole system and the convergence of the tracking error can be guaranteed. Finally, the availability of the proposed method is verified by simulation on 3-DOF hover to ensure that the system performance under faulty conditions can be quickly recovered to its normal level. And this proposed method is also proved to be better than that of LQR through simulation.

  20. DNA repair in human cells

    International Nuclear Information System (INIS)

    Regan, J.D.; Carrier, W.L.; Kusano, I.; Furuno-Fukushi, I.; Dunn, W.C. Jr.; Francis, A.A.; Lee, W.H.

    1982-01-01

    Our primary objective is to elucidate the molecular events in human cells when cellular macromolecules such as DNA are damaged by radiation or chemical agents. We study and characterize (i) the sequence of DNA repair events, (ii) the various modalities of repair, (iii) the genetic inhibition of repair due to mutation, (iv) the physiological inhibition of repair due to mutation, (v) the physiological inhibition of repair due to biochemical inhibitors, and (vi) the genetic basis of repair. Our ultimate goals are to (i) isolate and analyze the repair component of the mutagenic and/or carcinogenic event in human cells, and (ii) elucidate the magnitude and significance of this repair component as it impinges on the practical problems of human irradiation or exposure to actual or potential chemical mutagens and carcinogens. The significance of these studies lies in (i) the ubiquitousness of repair (most organisms, including man, have several complex repair systems), (ii) the belief that mutagenic and carcinogenic events may arise only from residual (nonrepaired) lesions or that error-prone repair systems may be the major induction mechanisms of the mutagenic or carcinogenic event, and (iii) the clear association of repair defects and highly carcinogenic disease states in man [xeroderma pigmentosum (XP)

  1. Studies on the molecular mechanism of nucleotide excision repair in human cells

    International Nuclear Information System (INIS)

    Friedberg, E.C.

    1987-01-01

    Studies in this laboratory have focused on attempts to define the mechanism of nucleotide excision repair of DNA in human cells, with a view to understanding the molecular pathogenesis of the disease XP. With the advent of recombinant DNA technology, they directed their efforts to the molecular cloning of human genes defective in XP, with a view to using the cloned genes to overexpress proteins of interest for biochemical investigations. Initial studies exploited the selectable phenotype of marked sensitivity to killing of XP group A cells by UV radiation and by other DNA damaging agents. However, except for a single report in 1982 there has been no reproducible demonstration of complementation of the UV sensitivity of XP cells by DNA-mediated transfection. The apparent difficulties associated with transfection of XP cells have been the subject of several recent studies. In view of the multiple problems associated with stable transfection of XP cells using total genomic DNA, they have embarked on an alternative strategy designed to facilitate the cloning of human XP genes. This strategy involves the transfer of single human chromosomes into XP cells and screening for this relatively high frequency event. The idea is to identify chromosomes on which particular XP genes reside and then to isolate non-complementing derivatives of these chromosomes so that highly enriched DNA pools containing genes of interest can be generated by employing one or more subtractive strategies

  2. Evaluation of Uniform Cost Accounting System to Fully Capture Depot Level Repair Costs.

    Science.gov (United States)

    1985-12-01

    RD-RI65 522 EVALUATION OF UNIFORM COST ACCOUNTING SYSTEM TO FULLY i/I CAPTURE DEPOT LEVEL REPAIR COSTS (U) NAVAL POSTGRADUATE SCHOOL MONTEREY CA D R...8217.LECTE B ,- THESIS EVALUATION OF UNIFORM COST ACCOUNTING SYSTEM 0TO FULLY CAPTURE DEPOT LEVEL REPAIR COSTS Jby __jDavid Richmond O’Brien lj,,, December...Include Security Classification) EVALUATION OF UNIFORM COST ACCOUNTING SYSTEM TO FULLY CAPTURE DEPOT LEVEL REPAIR COSTS 12 PERSONAL AUTHOR(S) O’Brien- David

  3. Guardians of the mycobacterial genome: A review on DNA repair systems in Mycobacterium tuberculosis.

    Science.gov (United States)

    Singh, Amandeep

    2017-12-01

    The genomic integrity of Mycobacterium tuberculosis is continuously threatened by the harsh survival conditions inside host macrophages, due to immune and antibiotic stresses. Faithful genome maintenance and repair must be accomplished under stress for the bacillus to survive in the host, necessitating a robust DNA repair system. The importance of DNA repair systems in pathogenesis is well established. Previous examination of the M. tuberculosis genome revealed homologues of almost all the major DNA repair systems, i.e. nucleotide excision repair (NER), base excision repair (BER), homologous recombination (HR) and non-homologous end joining (NHEJ). However, recent developments in the field have pointed to the presence of novel proteins and pathways in mycobacteria. Homologues of archeal mismatch repair proteins were recently reported in mycobacteria, a pathway previously thought to be absent. RecBCD, the major nuclease-helicase enzymes involved in HR in E. coli, were implicated in the single-strand annealing (SSA) pathway. Novel roles of archeo-eukaryotic primase (AEP) polymerases, previously thought to be exclusive to NHEJ, have been reported in BER. Many new proteins with a probable role in DNA repair have also been discovered. It is now realized that the DNA repair systems in M. tuberculosis are highly evolved and have redundant backup mechanisms to mend the damage. This review is an attempt to summarize our current understanding of the DNA repair systems in M. tuberculosis.

  4. Injectable systems and implantable conduits for peripheral nerve repair

    International Nuclear Information System (INIS)

    Lin, Yen-Chih; Marra, Kacey G

    2012-01-01

    Acute sensory problems following peripheral nerve injury include pain and loss of sensation. Approximately 360 000 people in the United States suffer from upper extremity paralytic syndromes every year. Restoration of sufficient functional recovery after long-gap peripheral nerve damage remains a clinical challenge. Potential nerve repair therapies have increased in the past decade as the field of tissue engineering expands. The following review describes the use of biomaterials in nerve tissue engineering. Namely, the use of both synthetic and natural biomaterials, including non-degradable and degradable nerve grafts, is addressed. The enhancement of axonal regeneration can be achieved by further modification of the nerve guides. These approaches include injectable hydrogel fillers, controlled drug delivery systems, and cell incorporation. Hydrogels are a class of liquid–gel biomaterials with high water content. Injectable and gelling hydrogels can serve as growth factor delivery vehicles and cell carriers for tissue engineering applications. While natural hydrogels and polymers are suitable for short gap nerve repair, the use of polymers for relatively long gaps remains a clinical challenge. (paper)

  5. PMS2 gene mutation results in DNA mismatch repair system failure in a case of adult granulosa cell tumor

    OpenAIRE

    Wang, Wen-Chung; Lee, Ya-Ting; Lai, Yen-Chein

    2017-01-01

    Background Granulosa cell tumors are rare ovarian malignancies. Their characteristics include unpredictable indolent growth with malignant potential and late recurrence. Approximately 95% are of adult type. Recent molecular studies have characterized the FOXL2 402C?>?G mutation in adult granulosa cell tumor. Our previous case report showed that unique FOXL2 402C?>?G mutation and defective DNA mismatch repair system are associated with the development of adult granulosa cell tumor. Findings In...

  6. Extending minimal repair models for repairable systems: A comparison of dynamic and heterogeneous extensions of a nonhomogeneous Poisson process

    International Nuclear Information System (INIS)

    Asfaw, Zeytu Gashaw; Lindqvist, Bo Henry

    2015-01-01

    For many applications of repairable systems, the minimal repair assumption, which leads to nonhomogeneous Poisson processes (NHPP), is not adequate. We review and study two extensions of the NHPP, the dynamic NHPP and the heterogeneous NHPP. Both extensions are motivated by specific aspects of potential applications. It has long been known, however, that the two paradigms are essentially indistinguishable in an analysis of failure data. We investigate the connection between the two approaches for extending NHPP models, both theoretically and numerically in a data example and a simulation study. - Highlights: • Review of dynamic extension of a minimal repair model (LEYP), introduced by Le Gat. • Derivation of likelihood function and comparison to NHPP model with heterogeneity. • Likelihood functions and conditional intensities are similar for the models. • ML estimation is considered for both models using a power law baseline. • A simulation study illustrates and confirms findings of the theoretical study

  7. DNA repair protocols

    DEFF Research Database (Denmark)

    Bjergbæk, Lotte

    In its 3rd edition, this Methods in Molecular Biology(TM) book covers the eukaryotic response to genomic insult including advanced protocols and standard techniques in the field of DNA repair. Offers expert guidance for DNA repair, recombination, and replication. Current knowledge of the mechanisms...... that regulate DNA repair has grown significantly over the past years with technology advances such as RNA interference, advanced proteomics and microscopy as well as high throughput screens. The third edition of DNA Repair Protocols covers various aspects of the eukaryotic response to genomic insult including...... recent advanced protocols as well as standard techniques used in the field of DNA repair. Both mammalian and non-mammalian model organisms are covered in the book, and many of the techniques can be applied with only minor modifications to other systems than the one described. Written in the highly...

  8. A deteriorating two-system with two repair modes and sojourn times phase-type distributed

    International Nuclear Information System (INIS)

    Montoro-Cazorla, Delia; Perez-Ocon, Rafael

    2006-01-01

    We study a two-unit cold standby system in steady-state. The online unit goes through a finite number of stages of successive degradation preceding the failure. The units are reparable, there is a repairman and two types of maintenance are considered, preventive and corrective. The preventive repair aims to improve the degradation of a unit being operative. The corrective repair is necessary when the unit fails. We will assume that the preventive repair will be interrupted in favour of a corrective repair in order to increase the availability of the system. The random operational and repair times follow phase-type distributions. For this system, the stationary probability vector, the replacement times, and the involved costs are calculated. An optimisation problem is illustrated by a numerical example. In this, the optimal degradation stage for the preventive repair of the online unit is determined by taking into account the system availability and the incurred costs

  9. A deteriorating two-system with two repair modes and sojourn times phase-type distributed

    Energy Technology Data Exchange (ETDEWEB)

    Montoro-Cazorla, Delia [Departamento de Estadistica e I.O., Escuela Politecnica de Linares, Universidad de Jaen, 23700 Linares, Jaen (Spain); Perez-Ocon, Rafael [Departamento de Estadistica e I.O., Facultad de Ciencias, Universidad de Granada, Granada 18071 (Spain)]. E-mail: rperezo@ugr.es

    2006-01-01

    We study a two-unit cold standby system in steady-state. The online unit goes through a finite number of stages of successive degradation preceding the failure. The units are reparable, there is a repairman and two types of maintenance are considered, preventive and corrective. The preventive repair aims to improve the degradation of a unit being operative. The corrective repair is necessary when the unit fails. We will assume that the preventive repair will be interrupted in favour of a corrective repair in order to increase the availability of the system. The random operational and repair times follow phase-type distributions. For this system, the stationary probability vector, the replacement times, and the involved costs are calculated. An optimisation problem is illustrated by a numerical example. In this, the optimal degradation stage for the preventive repair of the online unit is determined by taking into account the system availability and the incurred costs.

  10. Recognition, signaling, and repair of DNA double-strand breaks produced by ionizing radiation in mammalian cells: the molecular choreography.

    Science.gov (United States)

    Thompson, Larry H

    2012-01-01

    The faithful maintenance of chromosome continuity in human cells during DNA replication and repair is critical for preventing the conversion of normal diploid cells to an oncogenic state. The evolution of higher eukaryotic cells endowed them with a large genetic investment in the molecular machinery that ensures chromosome stability. In mammalian and other vertebrate cells, the elimination of double-strand breaks with minimal nucleotide sequence change involves the spatiotemporal orchestration of a seemingly endless number of proteins ranging in their action from the nucleotide level to nucleosome organization and chromosome architecture. DNA DSBs trigger a myriad of post-translational modifications that alter catalytic activities and the specificity of protein interactions: phosphorylation, acetylation, methylation, ubiquitylation, and SUMOylation, followed by the reversal of these changes as repair is completed. "Superfluous" protein recruitment to damage sites, functional redundancy, and alternative pathways ensure that DSB repair is extremely efficient, both quantitatively and qualitatively. This review strives to integrate the information about the molecular mechanisms of DSB repair that has emerged over the last two decades with a focus on DSBs produced by the prototype agent ionizing radiation (IR). The exponential growth of molecular studies, heavily driven by RNA knockdown technology, now reveals an outline of how many key protein players in genome stability and cancer biology perform their interwoven tasks, e.g. ATM, ATR, DNA-PK, Chk1, Chk2, PARP1/2/3, 53BP1, BRCA1, BRCA2, BLM, RAD51, and the MRE11-RAD50-NBS1 complex. Thus, the nature of the intricate coordination of repair processes with cell cycle progression is becoming apparent. This review also links molecular abnormalities to cellular pathology as much a possible and provides a framework of temporal relationships. Copyright © 2012 Elsevier B.V. All rights reserved.

  11. DNA repair systems and the pathogenesis of Mycobacterium tuberculosis: varying activities at different stages of infection.

    Science.gov (United States)

    Gorna, Alina E; Bowater, Richard P; Dziadek, Jaroslaw

    2010-05-25

    Mycobacteria, including most of all MTB (Mycobacterium tuberculosis), cause pathogenic infections in humans and, during the infectious process, are exposed to a range of environmental insults, including the host's immune response. From the moment MTB is exhaled by infected individuals, through an active and latent phase in the body of the new host, until the time they reach the reactivation stage, MTB is exposed to many types of DNA-damaging agents. Like all cellular organisms, MTB has efficient DNA repair systems, and these are believed to play essential roles in mycobacterial pathogenesis. As different stages of infection have great variation in the conditions in which mycobacteria reside, it is possible that different repair systems are essential for progression to specific phases of infection. MTB possesses homologues of DNA repair systems that are found widely in other species of bacteria, such as nucleotide excision repair, base excision repair and repair by homologous recombination. MTB also possesses a system for non-homologous end-joining of DNA breaks, which appears to be widespread in prokaryotes, although its presence is sporadic within different species within a genus. However, MTB does not possess homologues of the typical mismatch repair system that is found in most bacteria. Recent studies have demonstrated that DNA repair genes are expressed differentially at each stage of infection. In the present review, we focus on different DNA repair systems from mycobacteria and identify questions that remain in our understanding of how these systems have an impact upon the infection processes of these important pathogens.

  12. DNA repair in B. subtilis: an inducible dimer-specific W-reactivation system

    International Nuclear Information System (INIS)

    Fields, P.I.; Yasbin, R.E.

    1982-01-01

    The W-reactivation system of Bacillus subtilis can repair pyrimidine dimers in bacteriophage DNA. This inducible repair system can be activated by treatment of the bacteria with uv, alkylating agents, cross-linking agents and gamma irradiation. However, bacteriophage treated with agents other than those that cause pyrimidine dimers to be produced was not repaired by this unique form of W-reactivation. In contrast, the W-reactivation system of Escherichia coli can repair a variety of damages placed in the bacteriophage DNA

  13. Information theory of molecular systems

    CERN Document Server

    Nalewajski, Roman F

    2006-01-01

    As well as providing a unified outlook on physics, Information Theory (IT) has numerous applications in chemistry and biology owing to its ability to provide a measure of the entropy/information contained within probability distributions and criteria of their information ""distance"" (similarity) and independence. Information Theory of Molecular Systems applies standard IT to classical problems in the theory of electronic structure and chemical reactivity. The book starts by introducing the basic concepts of modern electronic structure/reactivity theory based upon the Density Functional Theory

  14. ARCHER-Advanced System for RPVH Inspection and Repair

    International Nuclear Information System (INIS)

    Tomasic, Tomislav; Vukovic, Igor; Bakic, Ante

    2014-01-01

    The reactor pressure vessel head (RPVH) is an integral part of the reactor coolant pressure boundary. Its integrity is important for the safe and reliable operation of the nuclear power plant (NPP). After detection of the leakage and cracks in French NPP, followed by another that occurred in NPP in USA, methods and frequency of inspection were defined, and are strictly regulated by the US NRC Order EA-03-009 (substituted lately by ASME Code Case N-791-1) since 2003. Usual scope of inspection from inner side of RPVH comprises of visual inspection of the surface, ultrasonic testing (UT) and eddy current testing (ET) of the penetration nozzle and ET of the J-groove weld and nozzle outside surface below the weld. ARCHER, new INETEC's manipulator, is designed to provide full scope inspection of the RPVH, by use of various test modules and by performing the surface repair action on J-groove weld. It is adjustable to work with different types of penetration nozzles and thermal sleeves on both VVER and PWR type of NPP. Due to complex geometry each module is specially designed for particular type of examination. Modules are exchanged through the docking system without need for personnel to enter under the head region, thus reducing the personnel's exposure to the ionizing radiation. The end effectors are used to determine the surface flaws or cracks on inner diameter surface of penetration nozzle gap. It guides a slim sword-like probe which carries a pair of TOFD transducers for detection and sizing of circumferential and axial cracks, an eddy current cross-wounded coil, and a zero-degree UT probe through a gap between the penetration nozzle and thermal sleeve. In case of a non-sleeved penetration nozzle, an open housing module is used. J-groove module is designed to fit geometry of the J-groove weld of penetration nozzle, vent pipe and funnel guide. The whole weld area (2' mm on shell side and 1/2' on nozzle side) is covered by two specially designed

  15. Repairable system analysis in presence of covariates and random effects

    International Nuclear Information System (INIS)

    Giorgio, M.; Guida, M.; Pulcini, G.

    2014-01-01

    This paper aims to model the failure pattern of repairable systems in presence of explained and unexplained heterogeneity. The failure pattern of each system is described by a Power Law Process. Part of the heterogeneity among the patterns is explained through the use of a covariate, and the residual unexplained heterogeneity (random effects) is modeled via a joint probability distribution on the PLP parameters. The proposed approach is applied to a real set of failure time data of powertrain systems mounted on 33 buses employed in urban and suburban routes. Moreover, the joint probability distribution on the PLP parameters estimated from the data is used as an informative prior to make Bayesian inference on the future failure process of a generic system belonging to the same population and employed in an urban or suburban route under randomly chosen working conditions. - Highlights: • We describe the failure process of buses powertrain system subject to heterogeneity. • Heterogeneity due to different service types is explained by a covariate. • Random effect is modeled through a joint pdf on failure process parameters. • The powertrain reliability under new future operating conditions is estimated

  16. Molecular genetic and biochemical analyses of a DNA repair gene from Serratia marcescens

    International Nuclear Information System (INIS)

    Murphy, K.E.

    1989-01-01

    In Escherichia coli, the SOS response and two 3-methyladenine DNA glycosylases (TagI and TagII) are required for repair of DNA damaged by alkylating agents such as methyl methanesulfonate (MMS). Mutations of the recA gene eliminate the SOS response. TagI and TagII are encoded by the tag and alkA genes, respectively. A gene (rpr) encoding 3-methyladenine DNA glycosylase activity was isolated from the Gram-negative bacterium Serratia marcescens. The gene, localized to a 1.5-kilobase pair SmaI-HindIII restriction fragment, was cloned into plasmid pUC18. The clone complemented E. coli tag alkA and recA mutations for MMS resistance. The rpr gene did not, however, complement recA mutations for resistance to ultraviolet light or the ability to perform homologous recombination reactions, nor did it complement E. coli ada or alkB mutations. Two proteins of molecular weights 42,000 and 16,000 were produced from the rpr locus. Analysis of deletion and insertion mutants of rpr suggested that the 42kD molecule is the active protein. The 16kD protein may either be a breakdown product of the 42kD species or may be encoded by another gene overlapping the reading frame of the rpr gene. Biochemical assays showed that the rpr gene product (Rpr) possesses 3-methyladenine DNA glycosylase activity

  17. The Design of Intelligent Repair Welding Mechanism and Relative Control System of Big Gear

    Directory of Open Access Journals (Sweden)

    Hong-Yu LIU

    2014-10-01

    Full Text Available Effective repair of worn big gear has large influence on ensuring safety production and enhancing economic benefits. A kind of intelligent repair welding method was put forward mainly aimed at the big gear restriction conditions of high production cost, long production cycle and high- intensity artificial repair welding work. Big gear repair welding mechanism was designed in this paper. The work principle and part selection of big gear repair welding mechanism was introduced. The three dimensional mode of big gear repair welding mechanism was constructed by Pro/E three dimensional design software. Three dimensional motions can be realized by motor controlling ball screw. According to involute gear feature, the complicated curve motion on curved gear surface can be transformed to linear motion by orientation. By this way, the repair welding on worn gear area can be realized. In the design of big gear repair welding mechanism control system, Siemens S7-200 series hardware was chosen. Siemens STEP7 programming software was chosen as system design tool. The entire repair welding process was simulated by experiment simulation. It provides a kind of practical and feasible method for the intelligent repair welding of big worn gear.

  18. Repair Effect of Seaweed Polysaccharides with Different Contents of Sulfate Group and Molecular Weights on Damaged HK-2 Cells

    Directory of Open Access Journals (Sweden)

    Poonam Bhadja

    2016-05-01

    Full Text Available The structure–activity relationships and repair mechanism of six low-molecular-weight seaweed polysaccharides (SPSs on oxalate-induced damaged human kidney proximal tubular epithelial cells (HK-2 were investigated. These SPSs included Laminaria japonica polysaccharide, degraded Porphyra yezoensis polysaccharide, degraded Gracilaria lemaneiformis polysaccharide, degraded Sargassum fusiforme polysaccharide, Eucheuma gelatinae polysaccharide, and degraded Undaria pinnatifida polysaccharide. These SPSs have a narrow difference of molecular weight (from 1968 to 4020 Da after degradation by controlling H2O2 concentration. The sulfate group (–SO3H content of the six SPSs was 21.7%, 17.9%, 13.3%, 8.2%, 7.0%, and 5.5%, respectively, and the –COOH contents varied between 1.0% to 1.7%. After degradation, no significant difference was observed in the contents of characteristic –SO3H and –COOH groups of polysaccharides. The repair effect of polysaccharides was determined using cell-viability test by CCK-8 assay and cell-morphology test by hematoxylin-eosin staining. The results revealed that these SPSs within 0.1–100 μg/mL did not express cytotoxicity in HK-2 cells, and each polysaccharide had a repair effect on oxalate-induced damaged HK-2 cells. Simultaneously, the content of polysaccharide –SO3H was positively correlated with repair ability. Furthermore, the low-molecular-weight degraded polysaccharides showed better repair activity on damaged HK-2 cells than their undegraded counterpart. Our results can provide reference for inhibiting the formation of kidney stones and for developing original anti-stone polysaccharide drugs.

  19. Homology modeling, molecular docking and DNA binding studies of nucleotide excision repair UvrC protein from M. tuberculosis.

    Science.gov (United States)

    Parulekar, Rishikesh S; Barage, Sagar H; Jalkute, Chidambar B; Dhanavade, Maruti J; Fandilolu, Prayagraj M; Sonawane, Kailas D

    2013-08-01

    Mycobacterium tuberculosis is a Gram positive, acid-fast bacteria belonging to genus Mycobacterium, is the leading causative agent of most cases of tuberculosis. The pathogenicity of the bacteria is enhanced by its developed DNA repair mechanism which consists of machineries such as nucleotide excision repair. Nucleotide excision repair consists of excinuclease protein UvrABC endonuclease, multi-enzymatic complex which carries out repair of damaged DNA in sequential manner. UvrC protein is a part of this complex and thus helps to repair the damaged DNA of M. tuberculosis. Hence, structural bioinformatics study of UvrC protein from M. tuberculosis was carried out using homology modeling and molecular docking techniques. Assessment of the reliability of the homology model was carried out by predicting its secondary structure along with its model validation. The predicted structure was docked with the ATP and the interacting amino acid residues of UvrC protein with the ATP were found to be TRP539, PHE89, GLU536, ILE402 and ARG575. The binding of UvrC protein with the DNA showed two different domains. The residues from domain I of the protein VAL526, THR524 and LEU521 interact with the DNA whereas, amino acids interacting from the domain II of the UvrC protein included ARG597, GLU595, GLY594 and GLY592 residues. This predicted model could be useful to design new inhibitors of UvrC enzyme to prevent pathogenesis of Mycobacterium and so the tuberculosis.

  20. Effect of Moisture Exchange on Interface Formation in the Repair System Studied by X-ray Absorption

    NARCIS (Netherlands)

    Lukovic, M.; Ye, G.

    2015-01-01

    In concrete repair systems, material properties of the repair material and the interface are greatly influenced by the moisture exchange between the repair material and the substrate. If the substrate is dry, it can absorb water from the repair material and reduce its effective water-to-cement ratio

  1. Repair systems with exchangeable items and the longest queue mechanism

    NARCIS (Netherlands)

    Ravid, R.; Boxma, O.J.; Perry, D.

    2013-01-01

    We consider a repair facility consisting of one repairman and two arrival streams of failed items, from bases 1 and 2. The arrival processes are independent Poisson processes, and the repair times are independent and identically exponentially distributed. The item types are exchangeable, and a

  2. Repair systems with exchangeable items and the longest queue mechanism

    NARCIS (Netherlands)

    Ravid, R.; Boxma, O.J.; Perry, D.

    2011-01-01

    We consider a repair facility consisting of one repairman and two arrival streams of failed items, from bases 1 and 2. The arrival processes are independent Poisson processes, and the repair times are independent and identically exponentially distributed. The item types are exchangeable, and a

  3. Life forms employ different repair strategies of repair single- and double strand DNA breaks caused by different qualities of radiation: criticality of RecA mediated repair system

    International Nuclear Information System (INIS)

    Sharan, R.N.

    2013-01-01

    Different qualities of radiation, either through direct or indirect pathway, induce qualitative different spectrum of damages in DNA, which are also different in in vitro and in vivo systems. The single- and double strand breaks of DNA are of special interest as they lead to serious biological consequences. The implications of such damage to DNA and their processing by various inherent repair pathways together decide the fate of the living form

  4. Materials directed to implants for repairing Central Nervous System

    Directory of Open Access Journals (Sweden)

    Canillas, M.

    2014-12-01

    Full Text Available Central Nervous System (CNS can be damaged by a wide range of injuries and disorders which entail permanent disability in some cases. Moreover, CNS repairing process presents some complications. The natural repair mechanism, which consists on the glial scar formation, is triggered by the inflammatory process. Molecules delivered during these processes, inflammation and glial scar formation as well as oxygen and glucose deficiencies due to the injury, create an inhibitory environment for axon regeneration and remyelination which is known as “secondary injury”. Biomaterials are taking up an even more important role in repairing CNS. Physicochemical properties of some ceramic materials have inspired different applications to repair CNS as substrates, electrodes or molecule vehicles. Based on their biocompatibility, capability to neutralize reactive species involved in the inflammatory processes and their versatile processing to obtain scaffolds with different shapes and sizes, ceramics are a succulent offer in nervous tissue engineering. Furthermore, their possibilities have been increased with polymeric-ceramics composites development, which have given rise to new interesting horizon.Existen diferentes tipos de lesiones o desordenes del Sistema Nervioso Central (SNC que pueden provocar graves secuelas e incluso en algunos casos una discapacidad permanente. Además, el proceso de reparación del SNC tiene algunas complicaciones. El mecanismo natural de reacción a una lesión, el cual consiste en la formación de una cicatriz glial, es desencadenado por un proceso inflamatorio. Las moléculas liberadas durante estos procesos, la inflamación y formación de la cicatriz glial, así como la deficiencia en oxígeno y glucosa debidos a la lesión, crean un ambiente que inhibe la regeneración axonal creando la llamada “lesión secundaria”. Los biomateriales están adquiriendo un papel cada vez más importante en la reparación de SNC. Las

  5. Integrated analysis of mismatch repair system in malignant astrocytomas.

    Directory of Open Access Journals (Sweden)

    Irene Rodríguez-Hernández

    Full Text Available Malignant astrocytomas are the most aggressive primary brain tumors with a poor prognosis despite optimal treatment. Dysfunction of mismatch repair (MMR system accelerates the accumulation of mutations throughout the genome causing uncontrolled cell growth. The aim of this study was to characterize the MMR system defects that could be involved in malignant astrocytoma pathogenesis. We analyzed protein expression and promoter methylation of MLH1, MSH2 and MSH6 as well as microsatellite instability (MSI and MMR gene mutations in a set of 96 low- and high-grade astrocytomas. Forty-one astrocytomas failed to express at least one MMR protein. Loss of MSH2 expression was more frequent in low-grade astrocytomas. Loss of MLH1 expression was associated with MLH1 promoter hypermethylation and MLH1-93G>A promoter polymorphism. However, MSI was not related with MMR protein expression and only 5% of tumors were MSI-High. Furthermore, the incidence of tumors carrying germline mutations in MMR genes was low and only one glioblastoma was associated with Lynch syndrome. Interestingly, survival analysis identified that tumors lacking MSH6 expression presented longer overall survival in high-grade astrocytoma patients treated only with radiotherapy while MSH6 expression did not modify the prognosis of those patients treated with both radiotherapy and chemotherapy. Our findings suggest that MMR system alterations are a frequent event in malignant astrocytomas and might help to define a subgroup of patients with different outcome.

  6. In-Space Repair and Refurbishment of Thermal Protection System Structures for Reusable Launch Vehicles

    Science.gov (United States)

    Singh, M.

    2007-01-01

    Advanced repair and refurbishment technologies are critically needed for the thermal protection system of current space transportation systems as well as for future launch and crew return vehicles. There is a history of damage to these systems from impact during ground handling or ice during launch. In addition, there exists the potential for in-orbit damage from micrometeoroid and orbital debris impact as well as different factors (weather, launch acoustics, shearing, etc.) during launch and re-entry. The GRC developed GRABER (Glenn Refractory Adhesive for Bonding and Exterior Repair) material has shown multiuse capability for repair of small cracks and damage in reinforced carbon-carbon (RCC) material. The concept consists of preparing an adhesive paste of desired ceramic with appropriate additives and then applying the paste to the damaged/cracked area of the RCC composites with an adhesive delivery system. The adhesive paste cures at 100-120 C and transforms into a high temperature ceramic during reentry conditions. A number of plasma torch and ArcJet tests were carried out to evaluate the crack repair capability of GRABER materials for Reinforced Carbon-Carbon (RCC) composites. For the large area repair applications, Integrated Systems for Tile and Leading Edge Repair (InSTALER) have been developed and evaluated under various ArcJet testing conditions. In this presentation, performance of the repair materials as applied to RCC is discussed. Additionally, critical in-space repair needs and technical challenges are reviewed.

  7. Molecular - and genetic aspects of the repair of the lesions induced by the furocoumarin photoaddition in Sacharomyces cerevisiae : role of the PSO genes

    International Nuclear Information System (INIS)

    Henriques, J.A.P.

    1982-01-01

    Experiences with strains of Sacharomyces cerevisiae with the aim to obtain informations about molecular steps and genetic control of the DNA photo-induced lesion repair by furocoumarins are described. (M.A.) [pt

  8. Analysis of a carbon composite overwrap pipeline repair system

    Energy Technology Data Exchange (ETDEWEB)

    Duell, J.M.; Wilson, J.M. [Department of Mechanical Engineering, University of Tulsa, Tulsa, OK 74104 (United States); Kessler, M.R. [Department of Materials Science and Engineering, Iowa State University, Ames, IA 50011 (United States)], E-mail: mkessler@iastate.edu

    2008-11-15

    A relatively new method has been developed to stop external corrosion and structurally reinforce steel pipes by external wrapping of damaged sections using fibre reinforced polymer (FRP) materials. Several different defect geometries representing corrosion patches on steel pipe were characterized using finite-element analysis, by changing the circumferential length of the defect. Pipe vessels containing these defects along with the composite structural repairs were modeled and the results were compared to field tests to determine the effectiveness of the repairs. It was found that the defect width around the circumference had little impact on the ultimate rupture pressure of the repaired vessel, but influenced the stress state in the underlying pipe substrate.

  9. An Injury Paradigm to Investigate Central Nervous System Repair in Drosophila

    Science.gov (United States)

    Kato, Kentaro; Hidalgo, Alicia

    2013-01-01

    An experimental method has been developed to investigate the cellular responses to central nervous system (CNS) injury using the fruit-fly Drosophila. Understanding repair and regeneration in animals is a key question in biology. The damaged human CNS does not regenerate, and understanding how to promote the regeneration is one of main goals of medical neuroscience. The powerful genetic toolkit of Drosophila can be used to tackle the problem of CNS regeneration. A lesion to the CNS ventral nerve cord (VNC, equivalent to the vertebrate spinal cord) is applied manually with a tungsten needle. The VNC can subsequently be filmed in time-lapse using laser scanning confocal microscopy for up to 24 hr to follow the development of the lesion over time. Alternatively, it can be cultured, then fixed and stained using immunofluorescence to visualize neuron and glial cells with confocal microscopy. Using appropriate markers, changes in cell morphology and cell state as a result of injury can be visualized. With ImageJ and purposely developed plug-ins, quantitative and statistical analyses can be carried out to measure changes in wound size over time and the effects of injury in cell proliferation and cell death. These methods allow the analysis of large sample sizes. They can be combined with the powerful genetics of Drosophila to investigate the molecular mechanisms underlying CNS regeneration and repair. PMID:23567253

  10. An optimal replacement policy for a repairable system based on its repairman having vacations

    Energy Technology Data Exchange (ETDEWEB)

    Yuan Li [School of Aerospace Engineering and Applied Mechanics, Tongji University, Shanghai 200092 (China); Xu Jian, E-mail: xujian@tongji.edu.c [School of Aerospace Engineering and Applied Mechanics, Tongji University, Shanghai 200092 (China)

    2011-07-15

    This paper studies a cold standby repairable system with two different components and one repairman who can take multiple vacations. If there is a component which fails and the repairman is on vacation, the failed component will wait for repair until the repairman is available. In the system, assume that component 1 has priority in use. After repair, component 1 follows a geometric process repair, while component 2 can be repaired as good as new after failures. Under these assumptions, a replacement policy N based on the failed times of component 1 is studied. The system will be replaced if the failure times of component 1 reach N. The explicit expression of the expected cost rate is given, so that the optimal replacement time N{sup *} is determined. Finally, a numerical example is given to illustrate the theoretical results of the model.

  11. Modeling imperfectly repaired system data via grey differential equations with unequal-gapped times

    International Nuclear Information System (INIS)

    Guo Renkuan

    2007-01-01

    In this paper, we argue that grey differential equation models are useful in repairable system modeling. The arguments starts with the review on GM(1,1) model with equal- and unequal-spaced stopping time sequence. In terms of two-stage GM(1,1) filtering, system stopping time can be partitioned into system intrinsic function and repair effect. Furthermore, we propose an approach to use grey differential equation to specify a semi-statistical membership function for system intrinsic function times. Also, we engage an effort to use GM(1,N) model to model system stopping times and the associated operating covariates and propose an unequal-gapped GM(1,N) model for such analysis. Finally, we investigate the GM(1,1)-embed systematic grey equation system modeling of imperfectly repaired system operating data. Practical examples are given in step-by-step manner to illustrate the grey differential equation modeling of repairable system data

  12. In-Space Repair of Reinforced Carbon-Carbon Thermal Protection System Structures

    Science.gov (United States)

    Singh, Mrityunjay

    2006-01-01

    Advanced repair and refurbishment technologies are critically needed for the thermal protection system of current space transportation system as well as for future Crew Exploration Vehicles (CEV). The damage to these components could be caused by impact during ground handling or due to falling of ice or other objects during launch. In addition, in-orbit damage includes micrometeoroid and orbital debris impact as well as different factors (weather, launch acoustics, shearing, etc.) during launch and re-entry. The GRC developed GRABER (Glenn Refractory Adhesive for Bonding and Exterior Repair) material has shown multiuse capability for repair of small cracks and damage in reinforced carbon-carbon (RCC) material. The concept consists of preparing an adhesive paste of desired ceramic with appropriate additives and then applying the paste to the damaged/cracked area of the RCC composites with adhesive delivery system. The adhesive paste cures at 100-120 C and transforms into a high temperature ceramic during simulated entry conditions. A number of plasma torch and ArcJet tests were carried out to evaluate the crack repair capability of GRABER materials for Reinforced Carbon-Carbon (RCC) composites. For the large area repair applications, integrated system for tile and leading edge repair (InSTALER) have been developed. In this presentation, critical in-space repair needs and technical challenges as well as various issues and complexities will be discussed along with the plasma performance and post test characterization of repaired RCC materials.

  13. A modelling study of drying shrinkage damage in concrete repair systems

    NARCIS (Netherlands)

    Lukovic, M.; Savija, B.; Schlangen, E.; Ye, G.; van Breugel, K.

    2014-01-01

    Differential shrinkage between repair material and concrete substrate is considered to be the main cause of premature failure of repair systems (Martinola, Sadouki et al. 2001, Beushausen and Alexander 2007). Magnitude of induced stresses depends on many factors, for example the amount of restraint,

  14. A 3D Lattice Modelling Study of Drying Shrinkage Damage in Concrete Repair Systems

    NARCIS (Netherlands)

    Lukovic, M.; Savija, B.; Schlangen, H.E.J.G.; Ye, G.; van Breugel, K.

    2016-01-01

    Differential shrinkage between repair material and concrete substrate is considered to be the main cause of premature failure of repair systems. The magnitude of induced stresses depends on many factors, for example the degree of restraint, moisture gradients caused by curing and drying conditions,

  15. Availability and mean life time prediction of multistage degraded system with partial repairs

    International Nuclear Information System (INIS)

    Pham, Hoang; Suprasad, A.; Misra, R.B.

    1997-01-01

    In some environments, components might not always fail fully, but can degrade, and there can be multiple stages of degradation. In such cases, the efficiency of the system may decrease. After a certain stage of degradation the efficiency of the system may decrease to an unacceptable limit and can be considered as a total failure. However, the system can fail randomly from any stage. and can be repaired. Further, the repair action cannot bring the system to the good stage, but can make it operational and the failure rate of the system will, therefore, remain the same as before the failure. In this study, we present a model for predicting the reliability, availability, mean life time, and mean time to first failure of multistage degraded systems with partial repairs. In the analysis, state dependent transition rates for the degradation process, as well as repair processes, are considered. A numerical example is provided to illustrate the results

  16. Reliability analysis of repairable safety systems of a reprocessing plant allowing for tolerable system downtimes

    International Nuclear Information System (INIS)

    Schaefer, H.

    1987-01-01

    GRS has been engaged in safety analysises of the German Reprocessing Plant for several years. The development and verification of appropriate reliability analysis methods, the generation of data as well as the search for an adequate structural presentation of the results to form a basis of recommendations for technical or administrative measures or contributions to risk oriented evaluations have been or are in the process of being established. In contrast to NPP-studies, the reliability assessment of safety systems of a reprocessing plant is applied to repairable and often relatively small systems allowing for tolerable system downtimes. A sketch of the diverse cooling systems of a vessel containing a selfheating solution is given. The interruption of the cooling function for about one day might be tolerable before boiling will be reached. This interval is suitable for transfer of the solution to a spare vessel or for repairing the failed components, thus restoring the cooling function

  17. Targeting DNA repair systems in antitubercular drug development.

    Science.gov (United States)

    Minias, Alina; Brzostek, Anna; Dziadek, Jaroslaw

    2018-01-28

    Infections with Mycobacterium tuberculosis, the causative agent of tuberculosis, are difficult to treat using currently available chemotherapeutics. Clinicians agree on the urgent need for novel drugs to treat tuberculosis. In this mini review, we summarize data that prompts the consideration of DNA repair-associated proteins as targets for the development of new antitubercular compounds. We discuss data, including gene expression data, that highlight the importance of DNA repair genes during the pathogenic cycle as well as after exposure to antimicrobials currently in use. Specifically, we report experiments on determining the essentiality of DNA repair-related genes. We report the availability of protein crystal structures and summarize discovered protein inhibitors. Further, we describe phenotypes of available gene mutants of M. tuberculosis and model organisms Mycobacterium bovis and Mycobacterium smegmatis. We summarize experiments regarding the role of DNA repair-related proteins in pathogenesis and virulence performed both in vitro and in vivo during the infection of macrophages and animals. We detail the role of DNA repair genes in acquiring mutations, which influence the rate of drug resistance acquisition. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  18. The zebrafish as a gerontology model in nervous system aging, disease, and repair.

    Science.gov (United States)

    Van Houcke, Jessie; De Groef, Lies; Dekeyster, Eline; Moons, Lieve

    2015-11-01

    Considering the increasing number of elderly in the world's population today, developing effective treatments for age-related pathologies is one of the biggest challenges in modern medical research. Age-related neurodegeneration, in particular, significantly impacts important sensory, motor, and cognitive functions, seriously constraining life quality of many patients. Although our understanding of the causal mechanisms of aging has greatly improved in recent years, animal model systems still have much to tell us about this complex process. Zebrafish (Danio rerio) have gained enormous popularity for this research topic over the past decade, since their life span is relatively short but, like humans, they are still subject to gradual aging. In addition, the extensive characterization of its well-conserved molecular and cellular physiology makes the zebrafish an excellent model to unravel the underlying mechanisms of aging, disease, and repair. This review provides a comprehensive overview of the progress made in zebrafish gerontology, with special emphasis on nervous system aging. We review the evidence that classic hallmarks of aging can also be recognized within this small vertebrate, both at the molecular and cellular level. Moreover, we illustrate the high level of similarity with age-associated human pathologies through a survey of the functional deficits that arise as zebrafish age. Copyright © 2015 Elsevier B.V. All rights reserved.

  19. Reliability analysis of Markov history-dependent repairable systems with neglected failures

    International Nuclear Information System (INIS)

    Du, Shijia; Zeng, Zhiguo; Cui, Lirong; Kang, Rui

    2017-01-01

    Markov history-dependent repairable systems refer to the Markov repairable systems in which some states are changeable and dependent on recent evolutional history of the system. In practice, many Markov history-dependent repairable systems are subjected to neglected failures, i.e., some failures do not affect system performances if they can be repaired promptly. In this paper, we develop a model based on the theory of aggregated stochastic processes to describe the history-dependent behavior and the effect of neglected failures on the Markov history-dependent repairable systems. Based on the developed model, instantaneous and steady-state availabilities are derived to characterize the reliability of the system. Four reliability-related time distributions, i.e., distribution for the k th working period, distribution for the k th failure period, distribution for the real working time in an effective working period, distribution for the neglected failure time in an effective working period, are also derived to provide a more comprehensive description of the system's reliability. Thanks to the power of the theory of aggregated stochastic processes, closed-form expressions are obtained for all the reliability indexes and time distributions. Finally, the developed indexes and analysis methods are demonstrated by a numerical example. - Highlights: • Markovian history-dependent repairable systems with neglected failures is modeled. • Aggregated stochastic processes are used to derive reliability indexes and time distributions. • Closed-form expressions are derived for the considered indexes and distributions.

  20. On-Orbit Health Monitoring and Repair Assessment of Thermal Protection Systems, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — This SBIR project delivers On-orbit health MoNItoring and repair assessment of THERMal protection systems (OMNI_THERM). OMNI_THERM features impedance-based...

  1. Self-Repairing Flight Control System for Online Health Monitoring and Recovery, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — In this SBIR project, a reliable self-repairing Flight Control System (FCS) will be developed. To achieve this goal, an artificial Neural Network based Sensor...

  2. Evaluation of histological scoring systems for tissue-engineered, repaired and osteoarthritic cartilage

    NARCIS (Netherlands)

    Rutgers, M.; van Pelt, M.J.; Dhert, W.J.A.; Creemers, L.B.; Saris, D.B.F.

    2010-01-01

    Osteoarthritis and Cartilage Volume 18, Issue 1, January 2010, Pages 12-23 -------------------------------------------------------------------------------- Review Evaluation of histological scoring systems for tissue-engineered, repaired and osteoarthritic cartilage M. Rutgers†, M.J.P. van Pelt†,

  3. Systemic EP4 Inhibition Increases Adhesion Formation in a Murine Model of Flexor Tendon Repair.

    Directory of Open Access Journals (Sweden)

    Michael B Geary

    Full Text Available Flexor tendon injuries are a common clinical problem, and repairs are frequently complicated by post-operative adhesions forming between the tendon and surrounding soft tissue. Prostaglandin E2 and the EP4 receptor have been implicated in this process following tendon injury; thus, we hypothesized that inhibiting EP4 after tendon injury would attenuate adhesion formation. A model of flexor tendon laceration and repair was utilized in C57BL/6J female mice to evaluate the effects of EP4 inhibition on adhesion formation and matrix deposition during flexor tendon repair. Systemic EP4 antagonist or vehicle control was given by intraperitoneal injection during the late proliferative phase of healing, and outcomes were analyzed for range of motion, biomechanics, histology, and genetic changes. Repairs treated with an EP4 antagonist demonstrated significant decreases in range of motion with increased resistance to gliding within the first three weeks after injury, suggesting greater adhesion formation. Histologic analysis of the repair site revealed a more robust granulation zone in the EP4 antagonist treated repairs, with early polarization for type III collagen by picrosirius red staining, findings consistent with functional outcomes. RT-PCR analysis demonstrated accelerated peaks in F4/80 and type III collagen (Col3a1 expression in the antagonist group, along with decreases in type I collagen (Col1a1. Mmp9 expression was significantly increased after discontinuing the antagonist, consistent with its role in mediating adhesion formation. Mmp2, which contributes to repair site remodeling, increases steadily between 10 and 28 days post-repair in the EP4 antagonist group, consistent with the increased matrix and granulation zones requiring remodeling in these repairs. These findings suggest that systemic EP4 antagonism leads to increased adhesion formation and matrix deposition during flexor tendon healing. Counter to our hypothesis that EP4 antagonism

  4. A 3D Lattice Modelling Study of Drying Shrinkage Damage in Concrete Repair Systems

    Directory of Open Access Journals (Sweden)

    Mladena Luković

    2016-07-01

    Full Text Available Differential shrinkage between repair material and concrete substrate is considered to be the main cause of premature failure of repair systems. The magnitude of induced stresses depends on many factors, for example the degree of restraint, moisture gradients caused by curing and drying conditions, type of repair material, etc. Numerical simulations combined with experimental observations can be of great use when determining the influence of these parameters on the performance of repair systems. In this work, a lattice type model was used to simulate first the moisture transport inside a repair system and then the resulting damage as a function of time. 3D simulations were performed, and damage patterns were qualitatively verified with experimental results and cracking tendencies in different brittle and ductile materials. The influence of substrate surface preparation, bond strength between the two materials, and thickness of the repair material were investigated. Benefits of using a specially tailored fibre reinforced material, namely strain hardening cementitious composite (SHCC, for controlling the damage development due to drying shrinkage in concrete repairs was also examined.

  5. Shear Bond Strength of a Novel Porcelain Repair System for ...

    African Journals Online (AJOL)

    2018-04-04

    Apr 4, 2018 ... Each fracture type was examined under a stereomicroscope .... fracture types. Statistical analysis. The normal distribution of data was examined using the Kolmogorov–Smirnov test. Shear bond strength data of repaired CAD/CAM .... adhesives to enamel, dentine, and porcelain surfaces can be compared.

  6. Damage induced by continued corrosion in concrete repair systems

    NARCIS (Netherlands)

    Luckovic, M.; Savija, B.; Schlangen, E.

    2014-01-01

    Corrosion of steel reinforcement is the main cause of deterioration in reinforced concrete structures. After the repair, corrosion of the steel might continue and even accelerate. While the development of the corrosion cell depends on many parameters and is difficult to control, the occurrence of

  7. Failure Modes in Concrete Repair Systems due to Ongoing Corrosion

    NARCIS (Netherlands)

    Lukovic, M.; Šavija, B.; Ye, G.; Schlangen, H.E.J.G.; van Breugel, K.

    2017-01-01

    Corrosion of steel reinforcement is the main cause of deterioration in reinforced concrete structures. It can result in cracking and spalling of the concrete cover. After the damaged cover is repaired, reinforcement corrosion might continue and even accelerate. While the development of the corrosion

  8. Non-parametric estimation of the availability in a general repairable system

    International Nuclear Information System (INIS)

    Gamiz, M.L.; Roman, Y.

    2008-01-01

    This work deals with repairable systems with unknown failure and repair time distributions. We focus on the estimation of the instantaneous availability, that is, the probability that the system is functioning at a given time, which we consider as the most significant measure for evaluating the effectiveness of a repairable system. The estimation of the availability function is not, in general, an easy task, i.e., analytical techniques are difficult to apply. We propose a smooth estimation of the availability based on kernel estimator of the cumulative distribution functions (CDF) of the failure and repair times, for which the bandwidth parameters are obtained by bootstrap procedures. The consistency properties of the availability estimator are established by using techniques based on the Laplace transform

  9. Non-parametric estimation of the availability in a general repairable system

    Energy Technology Data Exchange (ETDEWEB)

    Gamiz, M.L. [Departamento de Estadistica e I.O., Facultad de Ciencias, Universidad de Granada, Granada 18071 (Spain)], E-mail: mgamiz@ugr.es; Roman, Y. [Departamento de Estadistica e I.O., Facultad de Ciencias, Universidad de Granada, Granada 18071 (Spain)

    2008-08-15

    This work deals with repairable systems with unknown failure and repair time distributions. We focus on the estimation of the instantaneous availability, that is, the probability that the system is functioning at a given time, which we consider as the most significant measure for evaluating the effectiveness of a repairable system. The estimation of the availability function is not, in general, an easy task, i.e., analytical techniques are difficult to apply. We propose a smooth estimation of the availability based on kernel estimator of the cumulative distribution functions (CDF) of the failure and repair times, for which the bandwidth parameters are obtained by bootstrap procedures. The consistency properties of the availability estimator are established by using techniques based on the Laplace transform.

  10. Application of Interfacial Propagation and Kinking Crack Concept to ECC/Concrete Overlay Repair System

    Directory of Open Access Journals (Sweden)

    Yaw ChiaHwan

    2014-01-01

    Full Text Available Research on the application of ultraductile engineered cementitious composite (ECC as overlay in the repair of deteriorated concrete structures is performed in this paper. Also, interfacial crack kinking and trapping mechanism experimentally observed in ECC/concrete overlay repair system are described by comparison of toughness and energy release rate. The mechanism involves cycles of extension, kinking, and arrest of interfacial crack into the overlay. Experimental testing of overlay repair system reveals significant improvements in load carrying capacity and ductility over conventional concrete overlay. The commonly observed overlay system failure mode of delamination or spalling is eliminated when ECC is applied. These failure modes are suppressed when ECC is used as an ideal and durable candidate overlay repair material.

  11. Molecular mechanism of radioadaptive response: A cross-adaptive response for enhanced repair of DNA damage in adapted cells

    International Nuclear Information System (INIS)

    Takaji Ikushima

    1997-01-01

    The radioadaptive response (RAR) has been attributed to the induction of a repair mechanism by low doses of ionizing radiation, but the molecular nature of the mechanism is not yet elucidated. We have characterized RAR in a series of experiments in cultured Chinese hamster V79 cells. A 4-h interval is required for the full expression of RAR, which decays with the progression of cell proliferation. Treatments with inhibitors of poly(ADP-ribose) polymerase, protein- or RNA synthesis, and protein kinase C suppress the RAR expression. The RAR cross-reacts on clastogenic lesions induced by other physical and chemical DNA-damaging agents. The presence of newly synthesised proteins has been detected during the expression period. Experiments performed using single-cell gel electrophoresis provided more direct evidence for a faster and enhaced DNA repair rate in adapted cells. Here, using single-cell gel electrophoresis, a cross-adaptive response has been demonstrated for enhanced repair of DNA damage induced by neocarzinostatin in radio-adapted cells. (author)

  12. A molecular biological study on the identification of the molecular species of DNA polymerases for repairing radiation-damaged DNA and the factors modifying the mutation rate

    Energy Technology Data Exchange (ETDEWEB)

    Yamada, Koichi; Inoue, Shuji [National Inst. of Health and Nutrition, Tokyo (Japan)

    1997-02-01

    Aiming at prevention and treatment of radiation damages, the authors have been investigating DNA damages by X-ray and its repairing mechanism, however, the molecular species of DNA polymerase which mediate the repairing could not been identified by biochemical methods using various inhibitors because of their low specificity. Therefore, in this study, anti-sense oligonucleotides for DNA polymerase {alpha}, {delta} and {epsilon} were obtained by chemical synthesis and transduced into human fibroblast cell, NB1RGB by three methods; endocytotic method, electroporation method and lipofection method. For the first method, the addition of those peptides into the cell culture at 5 {mu}M inhibited the polymerase activity by up to 30% and it was economically difficult to use at higher concentrations than it. For the electroporation method, different conditions were tested in the respects of initial potential, time constant and buffer, but the uptake of thimidine was scarcely decreased in the surviving cells, suggesting that the surviving rate would be short in the cells electroporated with those anti-sense peptides. For the lipofection method, among several cationic lipids tested, lipofectamine significantly enlarged the decrease of thymidine uptake by anti-sense {delta}, however it was considered that its application to DNA repairing is difficult because lipofectamine is strongly cytotoxic. Therefore, construction of a vector which allows to express anti-sense RNA in those cells is undertaken. (M.N.)

  13. A molecular biological study on the identification of the molecular species of DNA polymerases for repairing radiation-damaged DNA and the factors modifying the mutation rate

    International Nuclear Information System (INIS)

    Yamada, Koichi; Inoue, Shuji

    1997-01-01

    Aiming at prevention and treatment of radiation damages, the authors have been investigating DNA damages by X-ray and its repairing mechanism, however, the molecular species of DNA polymerase which mediate the repairing could not been identified by biochemical methods using various inhibitors because of their low specificity. Therefore, in this study, anti-sense oligonucleotides for DNA polymerase α, δ and ε were obtained by chemical synthesis and transduced into human fibroblast cell, NB1RGB by three methods; endocytotic method, electroporation method and lipofection method. For the first method, the addition of those peptides into the cell culture at 5 μM inhibited the polymerase activity by up to 30% and it was economically difficult to use at higher concentrations than it. For the electroporation method, different conditions were tested in the respects of initial potential, time constant and buffer, but the uptake of thimidine was scarcely decreased in the surviving cells, suggesting that the surviving rate would be short in the cells electroporated with those anti-sense peptides. For the lipofection method, among several cationic lipids tested, lipofectamine significantly enlarged the decrease of thymidine uptake by anti-sense δ, however it was considered that its application to DNA repairing is difficult because lipofectamine is strongly cytotoxic. Therefore, construction of a vector which allows to express anti-sense RNA in those cells is undertaken. (M.N.)

  14. In Vitro Comparison of the Bond Strength between Ceramic Repair Systems and Ceramic Materials and Evaluation of the Wettability.

    Science.gov (United States)

    Kocaağaoğlu, Hasan; Manav, Taha; Albayrak, Haydar

    2017-04-01

    When fracture of an all-ceramic restoration occurs, it can be necessary to repair without removing the restoration. Although there are many studies about the repair of metal-ceramic restorations, there are few about all-ceramic restorations. The aim of this study was to evaluate the shear bond strength between ceramic repair systems and esthetic core materials and to evaluate the wettability of all-ceramic core materials. Disk-like specimens (N = 90) made of three dental ceramic infrastructure materials (zirconia ceramic, alumina ceramic, glass ceramic) were polished with silicon carbide paper, prepared for bonding (abrasion with 30 μm diamond rotary cutting instrument). Thirty specimens of each infrastructure were obtained. Each infrastructure group was divided into three subgroups; they were bonded using 3 repair systems: Bisco Intraoral Repair Kit, Cimara & Cimara Zircon Repair System, and Clearfil Repair System. After 1200 thermocycles, shear bond strength was measured in a universal testing machine at a 0.5 mm/min crosshead speed. In addition, the contact angle values of the infrastructures after surface treatments were examined for wettability. Data were analyzed by using ANOVA and Tukey post hoc tests. Although there were no significant differences among the repair systems (p > 0.05) in the glass ceramic and zirconia groups, a significant difference was found among the repair systems in alumina infrastructure (p 0.05); however, a statistically significant difference was found among the repair systems (p < 0.05). No difference was found among the infrastructures and repair systems in terms of contact angle values. Cimara & Cimara Zircon Repair System had higher bond strength values than the other repair systems. Although no difference was found among the infrastructures and repair systems, contact wettability angle was decreased by surface treatments compared with polished surfaces. © 2015 by the American College of Prosthodontists.

  15. Control and repair system for radioactive nuclear fuel elements

    International Nuclear Information System (INIS)

    Shallenberger, J.M.; Hornak, L.P.; Desmarchais, W.E.

    1975-01-01

    Irradiated fuel, especially such containing Pu-239, are put in a shielding container for inspection or repair. This container consists of an inner and outer tube of, for example, stainless steel, between which there is a gap filled with water, mineral oil, or polyethylene. At the upper end of the shielding container a rotating sleeve is positioned, by means of a bearing. It contains, for instance, an access opening and an inspection opening which are shielded by means of plexiglass. The access hole is opened only for repair work. In oder to prevent radiation from escaping to the environment during withdrawal and inspection of the fuel elements a second shielding container or shielding tube may be put over the sleeve. (DG/PB) [de

  16. PMS2 gene mutation results in DNA mismatch repair system failure in a case of adult granulosa cell tumor.

    Science.gov (United States)

    Wang, Wen-Chung; Lee, Ya-Ting; Lai, Yen-Chein

    2017-03-27

    Granulosa cell tumors are rare ovarian malignancies. Their characteristics include unpredictable indolent growth with malignant potential and late recurrence. Approximately 95% are of adult type. Recent molecular studies have characterized the FOXL2 402C > G mutation in adult granulosa cell tumor. Our previous case report showed that unique FOXL2 402C > G mutation and defective DNA mismatch repair system are associated with the development of adult granulosa cell tumor. In this study, the DNA sequences of four genes, MSH2, MLH1, MSH6, and PMS2, in the DNA mismatch repair system were determined via direct sequencing to elucidate the exact mechanism for the development of this granulosa cell tumor. The results showed that two missense germline mutations, T485K and N775L, inactivate the PMS2 gene. The results of this case study indicated that although FOXL2 402C > G mutation determines the development of granulosa cell tumor, PMS2 mutation may be the initial driver of carcinogenesis. Immunohistochemistry-based tumor testing for mismatch repair gene expression may be necessary for granulosa cell tumors to determine their malignant potential or if they are part of Lynch syndrome.

  17. Molecular motor assembly of a biomimetic system

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    @@ Active biological molecules and functional structures can be fabricated into a bio-mimetic system by using molecular assembly method. Such materials can be used for the drug delivery, disease diagnosis and therapy, and new nanodevice construction.

  18. Stochastic behavior of a cold standby system with maximum repair time

    Directory of Open Access Journals (Sweden)

    Ashish Kumar

    2015-09-01

    Full Text Available The main aim of the present paper is to analyze the stochastic behavior of a cold standby system with concept of preventive maintenance, priority and maximum repair time. For this purpose, a stochastic model is developed in which initially one unit is operative and other is kept as cold standby. There is a single server who visits the system immediately as and when required. The server takes the unit under preventive maintenance after a maximum operation time at normal mode if one standby unit is available for operation. If the repair of the failed unit is not possible up to a maximum repair time, failed unit is replaced by new one. The failure time, maximum operation time and maximum repair time distributions of the unit are considered as exponentially distributed while repair and maintenance time distributions are considered as arbitrary. All random variables are statistically independent and repairs are perfect. Various measures of system effectiveness are obtained by using the technique of semi-Markov process and RPT. To highlight the importance of the study numerical results are also obtained for MTSF, availability and profit function.

  19. Structural, molecular and cellular functions of MSH2 and MSH6 during DNA mismatch repair, damage signaling and other noncanonical activities

    Energy Technology Data Exchange (ETDEWEB)

    Edelbrock, Michael A., E-mail: Edelbrock@findlay.edu [The University of Findlay, 1000 North Main Street, Findlay, OH 45840 (United States); Kaliyaperumal, Saravanan, E-mail: Saravanan.Kaliyaperumal@hms.harvard.edu [Division of Comparative Medicine and Pathology, New England Primate Research Center, One Pine Hill Drive, Southborough, MA 01772 (United States); Williams, Kandace J., E-mail: Kandace.williams@utoledo.edu [University of Toledo College of Medicine and Life Sciences, Department of Biochemistry and Cancer Biology, 3000 Transverse Dr., Toledo, OH 43614 (United States)

    2013-03-15

    The field of DNA mismatch repair (MMR) has rapidly expanded after the discovery of the MutHLS repair system in bacteria. By the mid 1990s yeast and human homologues to bacterial MutL and MutS had been identified and their contribution to hereditary non-polyposis colorectal cancer (HNPCC; Lynch syndrome) was under intense investigation. The human MutS homologue 6 protein (hMSH6), was first reported in 1995 as a G:T binding partner (GTBP) of hMSH2, forming the hMutSα mismatch-binding complex. Signal transduction from each DNA-bound hMutSα complex is accomplished by the hMutLα heterodimer (hMLH1 and hPMS2). Molecular mechanisms and cellular regulation of individual MMR proteins are now areas of intensive research. This review will focus on molecular mechanisms associated with mismatch binding, as well as emerging evidence that MutSα, and in particular, MSH6, is a key protein in MMR-dependent DNA damage response and communication with other DNA repair pathways within the cell. MSH6 is unstable in the absence of MSH2, however it is the DNA lesion-binding partner of this heterodimer. MSH6, but not MSH2, has a conserved Phe-X-Glu motif that recognizes and binds several different DNA structural distortions, initiating different cellular responses. hMSH6 also contains the nuclear localization sequences required to shuttle hMutSα into the nucleus. For example, upon binding to O{sup 6}meG:T, MSH6 triggers a DNA damage response that involves altered phosphorylation within the N-terminal disordered domain of this unique protein. While many investigations have focused on MMR as a post-replication DNA repair mechanism, MMR proteins are expressed and active in all phases of the cell cycle. There is much more to be discovered about regulatory cellular roles that require the presence of MutSα and, in particular, MSH6.

  20. Structural, molecular and cellular functions of MSH2 and MSH6 during DNA mismatch repair, damage signaling and other noncanonical activities

    International Nuclear Information System (INIS)

    Edelbrock, Michael A.; Kaliyaperumal, Saravanan; Williams, Kandace J.

    2013-01-01

    The field of DNA mismatch repair (MMR) has rapidly expanded after the discovery of the MutHLS repair system in bacteria. By the mid 1990s yeast and human homologues to bacterial MutL and MutS had been identified and their contribution to hereditary non-polyposis colorectal cancer (HNPCC; Lynch syndrome) was under intense investigation. The human MutS homologue 6 protein (hMSH6), was first reported in 1995 as a G:T binding partner (GTBP) of hMSH2, forming the hMutSα mismatch-binding complex. Signal transduction from each DNA-bound hMutSα complex is accomplished by the hMutLα heterodimer (hMLH1 and hPMS2). Molecular mechanisms and cellular regulation of individual MMR proteins are now areas of intensive research. This review will focus on molecular mechanisms associated with mismatch binding, as well as emerging evidence that MutSα, and in particular, MSH6, is a key protein in MMR-dependent DNA damage response and communication with other DNA repair pathways within the cell. MSH6 is unstable in the absence of MSH2, however it is the DNA lesion-binding partner of this heterodimer. MSH6, but not MSH2, has a conserved Phe-X-Glu motif that recognizes and binds several different DNA structural distortions, initiating different cellular responses. hMSH6 also contains the nuclear localization sequences required to shuttle hMutSα into the nucleus. For example, upon binding to O 6 meG:T, MSH6 triggers a DNA damage response that involves altered phosphorylation within the N-terminal disordered domain of this unique protein. While many investigations have focused on MMR as a post-replication DNA repair mechanism, MMR proteins are expressed and active in all phases of the cell cycle. There is much more to be discovered about regulatory cellular roles that require the presence of MutSα and, in particular, MSH6

  1. The polysaccharide and low molecular weight components of Opuntia ficus indica cladodes: Structure and skin repairing properties.

    Science.gov (United States)

    Di Lorenzo, Flaviana; Silipo, Alba; Molinaro, Antonio; Parrilli, Michelangelo; Schiraldi, Chiara; D'Agostino, Antonella; Izzo, Elisabetta; Rizza, Luisa; Bonina, Andrea; Bonina, Francesco; Lanzetta, Rosa

    2017-02-10

    The Opuntia ficus-indica multiple properties are reflected in the increasing interest of chemists in the identification of its natural components having pharmaceutical and/or cosmetical applications. Here we report the structural elucidation of Opuntia ficus-indica mucilage that highlighted the presence of components differing for their chemical nature and the molecular weight distribution. The high molecular weight components were identified as a linear galactan polymer and a highly branched xyloarabinan. The low molecular weight components were identified as lactic acid, D-mannitol, piscidic, eucomic and 2-hydroxy-4-(4'-hydroxyphenyl)-butanoic acids. A wound healing assay was performed in order to test the cicatrizing properties of the various components, highlighting the ability of these latter to fasten dermal regeneration using a simplified in vitro cellular model based on a scratched keratinocytes monolayer. The results showed that the whole Opuntia mucilage and the low molecular weight components are active in the wound repair. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. Reliability analysis of a repairable k-out-of-n system with some components being suspended when the system is down

    International Nuclear Information System (INIS)

    Li Xiaohu; Zuo, Ming J.; Yam, Richard C.M.

    2006-01-01

    A k-out-of-n system with independent exponential components is investigated. It is assumed that some working components are suspended as soon as the system is down, repair starts immediately when a component fails and repair times are independent and exponentially distributed. Formulas for various reliability indices of the system including mean time between failures, mean working time in a failure-repair cycle, and mean down time in a failure-repair cycle are derived

  3. Control of a maintenance system when failure and repair times have phase type distributions

    Science.gov (United States)

    Decassiamenesesrodrigues, Rita

    1990-09-01

    In the model of machine repair discussed there are M + R identical machines, M operating, and R spares. All machines are independent of one another. When an operating machine fails, it is sent to a single server repair station and immediately replaced by a spare machine, if one is available. The server has two available service types to choose from. There are waiting costs, repair costs, lost production costs, and switch-over costs. The following decision problem is treated: to obtain a stationary policy which determines the service type as a function of the state of the system in order to minimize the long-run average cost when failure and repair times have second-order Coxian distribution. This control problem is represented by a semi-Markov decision process. The policy-iteration algorithm and the value-iteration algorithm are used to obtain the optimal policy. Numerical results are given for these two optimization methods.

  4. Reliability analysis of repairable multi-state system with common bus performance sharing

    International Nuclear Information System (INIS)

    Yu, Huan; Yang, Jun; Mo, Huadong

    2014-01-01

    In this paper, an instantaneous availability model for repairable multi-state system (MSS) with common bus performance sharing is proposed. The repairable MSS consists of some multi-state units and a common bus performance redistribution system. Each unit in the system has several performance levels and must satisfy its individual random demand. A unit can transmit the surplus performance to other units in real time through the common bus performance redistribution system, if it has a performance that exceeds its demand. The entire system fails if the demand of any unit is not satisfied. A new method based on the combination of the stochastic process method and the universal generating function technique is suggested to evaluate the instantaneous availability and the mean instantaneous performance deficiency of the proposed repairable MSS. Two examples are given for applications in the end

  5. Optimal preventive maintenance and repair policies for multi-state systems

    International Nuclear Information System (INIS)

    Sheu, Shey-Huei; Chang, Chin-Chih; Chen, Yen-Luan; George Zhang, Zhe

    2015-01-01

    This paper studies the optimal preventive maintenance (PM) policies for multi-state systems. The scheduled PMs can be either imperfect or perfect type. The improved effective age is utilized to model the effect of an imperfect PM. The system is considered as in a failure state (unacceptable state) once its performance level falls below a given customer demand level. If the system fails before a scheduled PM, it is repaired and becomes operational again. We consider three types of major, minimal, and imperfect repair actions, respectively. The deterioration of the system is assumed to follow a non-homogeneous continuous time Markov process (NHCTMP) with finite state space. A recursive approach is proposed to efficiently compute the time-dependent distribution of the multi-state system. For each repair type, we find the optimal PM schedule that minimizes the average cost rate. The main implication of our results is that in determining the optimal scheduled PM, choosing the right repair type will significantly improve the efficiency of the system maintenance. Thus PM and repair decisions must be made jointly to achieve the best performance

  6. Repair system and mitomycin mutagenesis in Escherichia coli

    Energy Technology Data Exchange (ETDEWEB)

    Otsuji, N; Murayama, I [Kyushu Univ., Fukuoka (Japan). Faculty of Pharmaceutical Sciences

    1974-03-01

    Ultraviolet light sensitive mutants of E. coli defective at the uvrA, uvrB or uvrC locus showed increased sensitivity to the lethal effects of monofunctional mitomycin, 7-methoxymitosene (7-MMT) or decarbamoyl mitomycin C (DCMTC), as well as mitomycin C (MTC). (1) Treatment of wild type bacteria with these monofunctional mitomycins resulted in the production of single-strand breaks in DNA, which were repaired upon incubation in a growth medium. Such breaks in DNA were not produced in the UvrA and the UvrB mutants. In the UvrC mutant, single-strand breaks were produced by 7-MMT or by DCMTC, but these breaks were not repaired upon incubation. (2) Exposure of E. coli to MTC caused cross-linkage between DNA strands, which converted to a normally denaturable form during further incubation after treatment. This was not occurred in the UvrB strain. In the UvrC mutant, a portion of the cross-links was removed upon incubation. (3) 7-MMT and DCMTC induced mutation in UV sensitive UvrB and UvrC mutants with much higher frequency than in wild type bacteria, while MTC did not induce mutation in these Uvr-strains.

  7. Repair system and mitomycin mutagenesis in Escherichia coli

    International Nuclear Information System (INIS)

    Otsuji, Nozomu; Murayama, Ichiko

    1974-01-01

    Ultraviolet light sensitive mutants of E. coli defective at the uvrA, uvrB or uvrC locus showed increased sensitivity to the lethal effects of monofunctional mitomycin, 7-methoxymitosene (7-MMT) or decarbamoyl mitomycin C (DCMTC), as well as mitomycin C (MTC). (1) Treatment of wild type bacteria with these monofunctional mitomycins resulted in the production of single-strand breaks in DNA, which were repaired upon incubation in a growth medium. Such breaks in DNA were not produced in the UvrA and the UvrB mutants. In the UvrC mutant, single-strand breaks were produced by 7-MMT or by DCMTC, but these breaks were not repaired upon incubation. (2) Exposure of E. coli to MTC caused cross-linkage between DNA strands, which converted to a normally denaturable form during further incubation after treatment. This was not occurred in the UvrB strain. In the UvrC mutant, a portion of the cross-links was removed upon incubation. (3) 7-MMT and DCMTC induced mutation in UV sensitive UvrB and UvrC mutants with much higher frequency than in wild type bacteria, while MTC did not induce mutation in these Uvr-strains. (author)

  8. Flexible Software Solution for Information System of Maintenance and Repair in Armenian NPP Medzamor

    International Nuclear Information System (INIS)

    Stoilova Yordanova, V.; Manchev, B.

    2016-01-01

    Achieving high performance in maintenance and repair activities in nuclear facilities and good results in this area is not possible without proper planning. This includes long-term, medium-term and annual planning. A computerized information maintenance management system is a tool widely used by nuclear operators to achieve safe, reliable, stable and predictable plant operation. Development and implementation of such a system in the Armenian NPP Medzamor (ANPP) was initiated by the European Commission (EC) in August 2013 based on the decision of ANPP management to improve practice in terms of planning and carrying out maintenance and repair of plant structures, systems and components (SSCs). The main purpose for the development and deployment of information maintenance management system in ANPP is creation of a systematic approach to the distribution of tasks between the maintenance personnel as well as the timing and methods of their implementation - on which systems, structures and components, maintenance frequency, while the ultimate goal is to optimize the use of resources for maintenance and to ensure plant safe operation and reliability. In November 2013 a contract between European Commission and consortium Risk Engineering -David Holding was signed, including the following supplies: Hardware for the information system of ANPP (called us Archimed MRO); Specification, design and development of the software of Archimed MRO, installation of the system, data migration, training of ANPP staff operating the system, and 9 months trial operation. In the process of specifying the functionality of the system the main purpose was to provide modern information tools to help improve the work of ANPP personnel in the following areas: Optimization of ANPP maintenance program; Planning of maintenance, repair and overhaul (MRO) activities; Effective management of the processes of MRO; Analysis of the MRO results (trend analysis, recurrence of repairs, quality of the repairs

  9. Molecular cloning and analysis of DNA repair gene from the radioresistant bacterium deinococcus radiodurans

    International Nuclear Information System (INIS)

    Du Zeji; Wang Mingsuo

    1998-12-01

    Deinococcus radiodurans (Dr) possesses a prominent ability to repair DNA injury induced by various DNA-damaging agents including mitomycin C (MC), ultraviolet light (UV) and ionizing radiation. A DNA repair mutant Dr KH3111 is a streptomycin resistant (Sm R ) derivative of KH311 which is generated by treatment with nitrosoguanidine and is sensitive to MC, 8-trimethyl-psoralen, UV and γ-ray irradiation. Gene affected by a mutation in the mutant is identified and its nucleotide sequence is determined. A complete open reading frame (ORF) which encompassed the KH3111 mutation region is found and tentatively designated as orf144b. The deduced amino acid (aa) sequence of orf144b consists of 284 aa and has no significant homology to other known proteins. The exact KH3111 mutation site is one nucleotide altered (G to A) in the sequence of orf144b in the mutant. The KH3111 mutation causes the substitution of Gly for Glu at aa position 149 of Orf144b. Survival measurements of a revertant KH3112 which was produced by transforming with DNA containing a part of the orf144b gene of KD8301 showed that the resistances to MC, UV and γ-ray in the revertant were fully restored at a level equal to the wild type. Thus, the orf144b gene required for the multiple-DNA-damaging agent resistance of Dr was designated with the name of pprA (Pleiotropic gene promoting DNA repair). This new gene can express in E. coli at very high level, and make the host E. coli resistant to MC, UV and γ-ray. The pprA gene does not express in normal Dr, but it can be induced to express by treatment with MC, UV and γ-ray. It was thought that the PprA polypeptide is a cytoplasmic protein because of the absence of characteristics found in the aa sequence of membrane proteins

  10. Molecular cloning and biological characterization of the human excision repair gene ERCC-3

    International Nuclear Information System (INIS)

    Weeda, G.; van Ham, R.C.; Masurel, R.; Westerveld, A.; Odijk, H.; de Wit, J.; Bootsma, D.; van der Eb, A.J.; Hoeijmakers, J.H.

    1990-01-01

    In this report we present the cloning, partial characterization, and preliminary studies of the biological activity of a human gene, designated ERCC-3, involved in early steps of the nucleotide excision repair pathway. The gene was cloned after genomic DNA transfection of human (HeLa) chromosomal DNA together with dominant marker pSV3gptH to the UV-sensitive, incision-defective Chinese hamster ovary (CHO) mutant 27-1. This mutant belongs to complementation group 3 of repair-deficient rodent mutants. After selection of UV-resistant primary and secondary 27-1 transformants, human sequences associated with the induced UV resistance were rescued in cosmids from the DNA of a secondary transformant by using a linked dominant marker copy and human repetitive DNA as probes. From coinheritance analysis of the ERCC-3 region in independent transformants, we deduce that the gene has a size of 35 to 45 kilobases, of which one essential segment has so far been refractory to cloning. Conserved unique human sequences hybridizing to a 3.0-kilobase mRNA were used to isolate apparently full-length cDNA clones. Upon transfection to 27-1 cells, the ERCC-3 cDNA, inserted in a mammalian expression vector, induced specific and (virtually) complete correction of the UV sensitivity and unscheduled DNA synthesis of mutants of complementation group 3 with very high efficiency. Mutant 27-1 is, unlike other mutants of complementation group 3, also very sensitive toward small alkylating agents. This unique property of the mutant is not corrected by introduction of the ERCC-3 cDNA, indicating that it may be caused by an independent second mutation in another repair function. By hybridization to DNA of a human x rodent hybrid cell panel, the ERCC-3 gene was assigned to chromosome 2, in agreement with data based on cell fusion

  11. Are glutathione S transferases involved in DNA damage signalling? Interactions with DNA damage and repair revealed from molecular epidemiology studies

    Energy Technology Data Exchange (ETDEWEB)

    Dusinska, Maria, E-mail: Maria.DUSINSKA@nilu.no [CEE-Health Effects Group, NILU - Norwegian Institute for Air Research, Kjeller (Norway); Staruchova, Marta; Horska, Alexandra [Department of Experimental and Applied Genetics, Slovak Medical University, Bratislava (Slovakia); Smolkova, Bozena [Laboratory of Cancer Genetics, Cancer Research Institute of the Slovak Academy of Sciences, Bratislava (Slovakia); Collins, Andrew [Department of Nutrition, Faculty of Medicine, University of Oslo (Norway); Bonassi, Stefano [Unit of Clinical and Molecular Epidemiology, IRCCS San Raffaele Pisana, Rome (Italy); Volkovova, Katarina [Department of Experimental and Applied Genetics, Slovak Medical University, Bratislava (Slovakia)

    2012-08-01

    Glutathione S-transferases (GSTs) are members of a multigene family of isoenzymes that are important in the control of oxidative stress and in phase II metabolism. Acting non-enzymically, GSTs can modulate signalling pathways of cell proliferation, cell differentiation and apoptosis. Using a molecular epidemiology approach, we have investigated a potential involvement of GSTs in DNA damage processing, specifically the modulation of DNA repair in a group of 388 healthy adult volunteers; 239 with at least 5 years of occupational exposure to asbestos, stone wool or glass fibre, and 149 reference subjects. We measured DNA damage in lymphocytes using the comet assay (alkaline single cell gel electrophoresis): strand breaks (SBs) and alkali-labile sites, oxidised pyrimidines with endonuclease III, and oxidised purines with formamidopyrimidine DNA glycosylase. We also measured GST activity in erythrocytes, and the capacity for base excision repair (BER) in a lymphocyte extract. Polymorphisms in genes encoding three GST isoenzymes were determined, namely deletion of GSTM1 and GSTT1 and single nucleotide polymorphism Ile105Val in GSTP1. Consumption of vegetables and wine correlated negatively with DNA damage and modulated BER. GST activity correlated with oxidised bases and with BER capacity, and differed depending on polymorphisms in GSTP1, GSTT1 and GSTM1. A significantly lower BER rate was associated with the homozygous GSTT1 deletion in all asbestos site subjects and in the corresponding reference group. Multifactorial analysis revealed effects of sex and exposure in GSTP1 Ile/Val heterozygotes but not in Ile/Ile homozygotes. These variants affected also SBs levels, mainly by interactions of GSTP1 genotype with exposure, with sex, and with smoking habit; and by an interaction between sex and smoking. Our results show that GST polymorphisms and GST activity can apparently influence DNA stability and repair of oxidised bases, suggesting a potential new role for these

  12. Are glutathione S transferases involved in DNA damage signalling? Interactions with DNA damage and repair revealed from molecular epidemiology studies

    International Nuclear Information System (INIS)

    Dusinska, Maria; Staruchova, Marta; Horska, Alexandra; Smolkova, Bozena; Collins, Andrew; Bonassi, Stefano; Volkovova, Katarina

    2012-01-01

    Glutathione S-transferases (GSTs) are members of a multigene family of isoenzymes that are important in the control of oxidative stress and in phase II metabolism. Acting non-enzymically, GSTs can modulate signalling pathways of cell proliferation, cell differentiation and apoptosis. Using a molecular epidemiology approach, we have investigated a potential involvement of GSTs in DNA damage processing, specifically the modulation of DNA repair in a group of 388 healthy adult volunteers; 239 with at least 5 years of occupational exposure to asbestos, stone wool or glass fibre, and 149 reference subjects. We measured DNA damage in lymphocytes using the comet assay (alkaline single cell gel electrophoresis): strand breaks (SBs) and alkali-labile sites, oxidised pyrimidines with endonuclease III, and oxidised purines with formamidopyrimidine DNA glycosylase. We also measured GST activity in erythrocytes, and the capacity for base excision repair (BER) in a lymphocyte extract. Polymorphisms in genes encoding three GST isoenzymes were determined, namely deletion of GSTM1 and GSTT1 and single nucleotide polymorphism Ile105Val in GSTP1. Consumption of vegetables and wine correlated negatively with DNA damage and modulated BER. GST activity correlated with oxidised bases and with BER capacity, and differed depending on polymorphisms in GSTP1, GSTT1 and GSTM1. A significantly lower BER rate was associated with the homozygous GSTT1 deletion in all asbestos site subjects and in the corresponding reference group. Multifactorial analysis revealed effects of sex and exposure in GSTP1 Ile/Val heterozygotes but not in Ile/Ile homozygotes. These variants affected also SBs levels, mainly by interactions of GSTP1 genotype with exposure, with sex, and with smoking habit; and by an interaction between sex and smoking. Our results show that GST polymorphisms and GST activity can apparently influence DNA stability and repair of oxidised bases, suggesting a potential new role for these

  13. Self-repair in a Bidirectionally Coupled Astrocyte-Neuron (AN System based on Retrograde Signaling

    Directory of Open Access Journals (Sweden)

    John eWade

    2012-09-01

    Full Text Available In this paper we demonstrate that retrograde signaling via astrocytes may underpin self-repair in the brain. Faults manifest themselves in silent or near silent neurons caused by low transmission probability synapses; the enhancement of the transmission probability of a healthy neighbouring synapse by retrograde signaling can enhance the transmission probability of the faulty synapse (repair. Our model of self-repair is based on recent research showing that retrograde signaling via astrocytes can increase the probability of neurotransmitter release at damaged or low transmission probability synapses. The model demonstrates that astrocytes are capable of bidirectional communication with neurons which leads to modulation of synaptic activity, and that indirect signaling through retrograde messengers such as endocannabinoids leads to modulation of synaptic transmission probability. Although our model operates at the level of cells, it provides a new research direction on brain-like self-repair which can be extended to networks of astrocytes and neurons. It also provides a biologically inspired basis for developing highly adaptive, distributed computing systems that can, at fine levels of granularity, fault detect, diagnose and self-repair autonomously, without the traditional constraint of a central fault detect/repair unit.

  14. Performance evaluation of multi-state degraded systems with minimal repairs and imperfect preventive maintenance

    International Nuclear Information System (INIS)

    Soro, Isaac W.; Nourelfath, Mustapha; Ait-Kadi, Daoud

    2010-01-01

    In this paper, we develop a model for evaluating the availability, the production rate and the reliability function of multi-state degraded systems subjected to minimal repairs and imperfect preventive maintenance. The status of the system is considered to degrade with use. These degradations may lead to decrease in the system efficiency. It is assumed that the system can consecutively degrade into several discrete states, which are characterized by different performance rates, ranging from perfect functioning to complete failure. The latter is observed when the degradation level reaches a certain critical threshold such as the system efficiency may decrease to an unacceptable limit. In addition, the system can fail randomly from any operational or acceptable state and can be repaired. This repair action brings the system to its previous operational state without affecting its failure rate (i.e., minimal repair). The used preventive maintenance policy suggests that if the system reaches the last acceptable degraded state, it is brought back to one of the states with higher efficiency. Considering customer demand as constant, the system is modeled as a continuous-time Markov process to assess its instantaneous and stationary performance measures. A numerical example is given to illustrate the proposed model.

  15. Effects of caffeine or maternal repair systems in Drosophila melanogaster

    International Nuclear Information System (INIS)

    Osgood, C.; Zimmering, S.

    1979-01-01

    Drosophila melanogaster females were treated with 1% caffeine, mated with X-rayed males and the frequencies of induced sex-chromosome loss, translocations between the major autosomes and between the Y-chromosome and the major autosomes determined. In a reversal of the results obtained previously with 0.2% caffeine by Mendelson and Sobels, treatment of females with 1% caffeine led to a decrease in sex-chromosome loss, confirming preliminary data of Zimmering and Osgood and in increase in autosome-autosome translocations. It is suggested that the higher concentration of caffeine inhibits replication permitting more time available for chromosome-type restitutions by means of caffeine-insensitive repair mechanisms. In contrast with results for autosome-autosome translocation, the fequency of Y-autosome translocations was depressed below controls suggesting an isolation (by any one of several means) of Y-chromosome breaks from those in the autosomes. (Auth.)

  16. Bayesian analysis of repairable systems showing a bounded failure intensity

    International Nuclear Information System (INIS)

    Guida, Maurizio; Pulcini, Gianpaolo

    2006-01-01

    The failure pattern of repairable mechanical equipment subject to deterioration phenomena sometimes shows a finite bound for the increasing failure intensity. A non-homogeneous Poisson process with bounded increasing failure intensity is then illustrated and its characteristics are discussed. A Bayesian procedure, based on prior information on model-free quantities, is developed in order to allow technical information on the failure process to be incorporated into the inferential procedure and to improve the inference accuracy. Posterior estimation of the model-free quantities and of other quantities of interest (such as the optimal replacement interval) is provided, as well as prediction on the waiting time to the next failure and on the number of failures in a future time interval is given. Finally, numerical examples are given to illustrate the proposed inferential procedure

  17. The food-borne pathogen Campylobacter jejuni depends on the AddAB DNA repair system to defend against bile in the intestinal environment.

    Science.gov (United States)

    Gourley, Christopher R; Negretti, Nicholas M; Konkel, Michael E

    2017-10-31

    Accurate repair of DNA damage is crucial to ensure genome stability and cell survival of all organisms. Bile functions as a defensive barrier against intestinal colonization by pathogenic microbes. Campylobacter jejuni, a leading bacterial cause of foodborne illness, possess strategies to mitigate the toxic components of bile. We recently found that growth of C. jejuni in medium with deoxycholate, a component of bile, caused DNA damage consistent with the exposure to reactive oxygen species. We hypothesized that C. jejuni must repair DNA damage caused by reactive oxygen species to restore chromosomal integrity. Our efforts focused on determining the importance of the putative AddAB DNA repair proteins. A C. jejuni addAB mutant demonstrated enhanced sensitivity to deoxycholate and was impaired in DNA double strand break repair. Complementation of the addAB mutant restored resistance to deoxycholate, as well as function of the DNA double strand break repair system. The importance of these findings translated to the natural host, where the AddAB system was found to be required for efficient C. jejuni colonization of the chicken intestine. This research provides new insight into the molecular mechanism utilized by C. jejuni, and possibly other intestinal pathogens, to survive in the presence of bile.

  18. Reaction dynamics in polyatomic molecular systems

    Energy Technology Data Exchange (ETDEWEB)

    Miller, W.H. [Lawrence Berkeley Laboratory, CA (United States)

    1993-12-01

    The goal of this program is the development of theoretical methods and models for describing the dynamics of chemical reactions, with specific interest for application to polyatomic molecular systems of special interest and relevance. There is interest in developing the most rigorous possible theoretical approaches and also in more approximate treatments that are more readily applicable to complex systems.

  19. The role of the bacterial mismatch repair system in SOS-induced mutagenesis: a theoretical background

    International Nuclear Information System (INIS)

    Belov, O.V.; Kapralov, M.I.; Chuluunbaatar, O.; Sweilam, N.H.

    2012-01-01

    A theoretical study is performed of the possible role of the methyl-directed mismatch repair system in the ultraviolet-induced mutagenesis of Escherichia coli bacterial cells. For this purpose, a mathematical model of the bacterial mismatch repair system is developed. Within this model, the key pathways of this type of repair are simulated on the basis of modern experimental data related to its mechanisms. Here we have modelled in detail five main pathways of DNA misincorporation removal with different DNA exonucleases. Using our calculations, we have tested the hypothesis that the bacterial mismatch repair system is responsible for the removal of the nucleotides misincorporated by DNA polymerase V (the UmuD' 2 C complex) during ultraviolet-induced SOS response. For the theoretical analysis of the mutation frequency, we have combined the proposed mathematical approach with the model of SOS-induced mutagenesis in the E.coli bacterial cell developed earlier. Our calculations support the hypothesis that methyl-directed mismatch repair influences the mutagenic effect of ultraviolet radiation

  20. Robotics in the nuclear environment-inspection and repairs inside the primary coolant system

    International Nuclear Information System (INIS)

    Guillet, J.; Marcel Tortolano

    2005-01-01

    The increase in the lifetime of the power plants and the ageing of materials require the intervention inside the components to carry out controls and possibly repairs in the event of discovered defects. Within this framework, EDF is investigating the feasibility of robotized repairs of the components and pipes of the main primary coolant system of a nuclear power plant. For several years, EDF R and D has engaged projects whose subject of study is the possibility of repairing components such as the main vessel; the pressurizer or the primary coolant pipes with the help of robots and dedicated tools. INTERVENTIONS INSIDE PRIMARY COOLANT PIPES: Studies undertaken by EDF highlighted that certain zones, particularly in pipe connections, can be affected by thermal fatigue which causes crackling defects or crackings. In anticipation of this phenomenon which would affect primary pipes and to avoid their replacements, EDF R and D has been studying the feasibility of examining and repairing these zones using robots. Robotized repair consists in introducing into the pipe while passing by the vessel, a 6 degrees of freedom manipulator mounted on a mobile carrier. This robot implements and carries out the trajectories of the different processes of repair: - Precise localization of the defects, - Elimination (possibly sampling) of the defects by machining, - Control that the defects were eliminated, - Weld metal buildup if the repair cavity is too deep, - Grinding followed by a new control of the surface. These studies and tests were conducted in the laboratory of EDF R and D in Chatou. The sequence of operations included machining by grinding and milling, profilometric control, dye penetrant testing, TIG welding and ultrasonic examinations. The results of the tests, executed on full scale models of components, are satisfactory and show the advantages of robotics compared with classical methods. ROBOTIZED INTERVENTIONS IN THE REACTOR VESSEL: Another difficult issue is the

  1. Pitfalls in molecular analysis for mismatch repair deficiency in a family with biallelic pms2 germline mutations.

    Science.gov (United States)

    Leenen, C H M; Geurts-Giele, W R R; Dubbink, H J; Reddingius, R; van den Ouweland, A M; Tops, C M J; van de Klift, H M; Kuipers, E J; van Leerdam, M E; Dinjens, W N M; Wagner, A

    2011-12-01

    Heterozygous germline mutations in the mismatch repair (MMR) genes MLH1, MSH2, MSH6 and PMS2 cause Lynch syndrome. Biallelic mutations in the MMR genes are associated with a childhood cancer syndrome [constitutional mismatch repair deficiency (CMMR-D)]. This is predominantly characterized by hematological malignancies and tumors of the bowel and brain, often associated with signs of neurofibromatosis type 1 (NF1). Diagnostic strategies for selection of patients for MMR gene analysis include analysis of microsatellite instability (MSI) and immunohistochemical (IHC) analysis of MMR proteins in tumor tissue. We report the clinical characterization and molecular analyses of tumor specimens from a family with biallelic PMS2 germline mutations. This illustrates the pitfalls of present molecular screening strategies. Tumor tissues of five family members were analyzed for MSI and IHC. MSI was observed in only one of the analyzed tissues. However, IHC analysis of brain tumor tissue of the index patient and his sister showed absence of PMS2 expression, and germline mutation analyses showed biallelic mutations in PMS2: p.Ser46IIe and p.Pro246fs. The same heterozygous mutations were confirmed in the father and mother, respectively. These data support the conclusion that in case of a clinical phenotype of CMMR-D, it is advisable to routinely combine MSI analysis with IHC analysis for the expression of MMR proteins. With inconclusive or conflicting results, germline mutation analysis of the MMR genes should be considered after thorough counselling of the patients and/or their relatives. © 2011 John Wiley & Sons A/S.

  2. The bases for optimisation of scheduled repairs and tests of safety systems to improve the NPP productive efficiency

    International Nuclear Information System (INIS)

    Bilej, D.V.; Vasil'chenko, S.V.; Vlasenko, N.I.; Vasil'chenko, V.N.; Skalozubov, V.I.

    2004-01-01

    In the frames of risk-informed approaches the paper proposed the theoretical bases for methods of optimisation of scheduled repairs and tests of safety systems at nuclear power plants. The optimisation criterion is the objective risk function minimising. This function depends on the scheduled repairs/tests periodicity and the allowed time to bring the system channel to a state of non-operability. The main optimisation direct is to reduce the repair time with the purpose of enhancement of productive efficiency

  3. RESTART simulation of non-Markov consecutive-k-out-of-n: F repairable systems

    International Nuclear Information System (INIS)

    Villen-Altamirano, Jose

    2010-01-01

    The reliability of consecutive-k-out-of-n: F repairable systems and (k-1)-step Markov dependence is studied. The model analyzed in this paper is more general than those of previous studies given that repair time and component lifetimes are random variables that follow a general distribution. The system has one repair service which adopts a priority repair rule based on system failure risk. Since crude simulation has proved to be inefficient for highly dependable systems, the RESTART method was used for the estimation of steady-state unavailability, MTBF and unreliability. Probabilities up to the order of 10 -16 have been accurately estimated with little computational effort. In this method, a number of simulation retrials are performed when the process enters regions of the state space where the chance of occurrence of a rare event (e.g., a system failure) is higher. The main difficulty for the application of this method is to find a suitable function, called the importance function, to define the regions. Given the simplicity involved in changing some model assumptions with RESTART, the importance function used in this paper could be useful for dependability estimation of many systems.

  4. Single-Molecule Methods for Nucleotide Excision Repair: Building a System to Watch Repair in Real Time

    OpenAIRE

    Kong, Muwen; Beckwitt, Emily C.; Springall, Luke; Kad, Neil M.; Van Houten, Bennett

    2017-01-01

    Single-molecule approaches to solving biophysical problems are powerful tools that allow static and dynamic real-time observations of specific molecular interactions of interest in the absence of ensemble-averaging effects. Here, we provide detailed protocols for building an experimental system that employs atomic force microscopy and a single-molecule DNA tightrope assay based on oblique angle illumination fluorescence microscopy. Together with approaches for engineering site-specific lesion...

  5. Effect of Moisture Exchange on Interface Formation in the Repair System Studied by X-ray Absorption

    Directory of Open Access Journals (Sweden)

    Mladena Lukovic

    2015-12-01

    Full Text Available In concrete repair systems, material properties of the repair material and the interface are greatly influenced by the moisture exchange between the repair material and the substrate. If the substrate is dry, it can absorb water from the repair material and reduce its effective water-to-cement ratio (w/c. This further affects the hydration rate of cement based material. In addition to the change in hydration rate, void content at the interface between the two materials is also affected. In this research, the influence of moisture exchange on the void content in the repair system as a function of initial saturation level of the substrate is investigated. Repair systems with varying level of substrate saturation are made. Moisture exchange in these repair systems as a function of time is monitored by the X-ray absorption technique. After a specified curing age (3 d, the internal microstructure of the repair systems was captured by micro-computed X-ray tomography (CT-scanning. From reconstructed images, different phases in the repair system (repair material, substrate, voids can be distinguished. In order to quantify the void content, voids were thresholded and their percentage was calculated. It was found that significantly more voids form when the substrate is dry prior to application of the repair material. Air, initially filling voids and pores of the dry substrate, is being released due to the moisture exchange. As a result, air voids remain entrapped in the repair material close to the interface. These voids are found to form as a continuation of pre-existing surface voids in the substrate. Knowledge about moisture exchange and its effects provides engineers with the basis for recommendations about substrate preconditioning in practice.

  6. Effect of Moisture Exchange on Interface Formation in the Repair System Studied by X-ray Absorption.

    Science.gov (United States)

    Lukovic, Mladena; Ye, Guang

    2015-12-22

    In concrete repair systems, material properties of the repair material and the interface are greatly influenced by the moisture exchange between the repair material and the substrate. If the substrate is dry, it can absorb water from the repair material and reduce its effective water-to-cement ratio (w/c). This further affects the hydration rate of cement based material. In addition to the change in hydration rate, void content at the interface between the two materials is also affected. In this research, the influence of moisture exchange on the void content in the repair system as a function of initial saturation level of the substrate is investigated. Repair systems with varying level of substrate saturation are made. Moisture exchange in these repair systems as a function of time is monitored by the X-ray absorption technique. After a specified curing age (3 d), the internal microstructure of the repair systems was captured by micro-computed X-ray tomography (CT-scanning). From reconstructed images, different phases in the repair system (repair material, substrate, voids) can be distinguished. In order to quantify the void content, voids were thresholded and their percentage was calculated. It was found that significantly more voids form when the substrate is dry prior to application of the repair material. Air, initially filling voids and pores of the dry substrate, is being released due to the moisture exchange. As a result, air voids remain entrapped in the repair material close to the interface. These voids are found to form as a continuation of pre-existing surface voids in the substrate. Knowledge about moisture exchange and its effects provides engineers with the basis for recommendations about substrate preconditioning in practice.

  7. Evaluation of temporary non-code repairs in safety class 3 piping systems

    International Nuclear Information System (INIS)

    Godha, P.C.; Kupinski, M.; Azevedo, N.F.

    1996-01-01

    Temporary non-ASME Code repairs in safety class 3 pipe and piping components are permissible during plant operation in accordance with Nuclear Regulatory Commission Generic Letter 90-05. However, regulatory acceptance of such repairs requires the licensee to undertake several timely actions. Consistent with the requirements of GL 90-05, this paper presents an overview of the detailed evaluation and relief request process. The technical criteria encompasses both ductile and brittle piping materials. It also lists appropriate evaluation methods that a utility engineer can select to perform a structural integrity assessment for design basis loading conditions to support the use of temporary non-Code repair for degraded piping components. Most use of temporary non-code repairs at a nuclear generating station is in the service water system which is an essential safety related system providing the ultimate heat sink for various plant systems. Depending on the plant siting, the service water system may use fresh water or salt water as the cooling medium. Various degradation mechanisms including general corrosion, erosion/corrosion, pitting, microbiological corrosion, galvanic corrosion, under-deposit corrosion or a combination thereof continually challenge the pressure boundary structural integrity. A good source for description of corrosion degradation in cooling water systems is provided in a cited reference

  8. Molecular target discovery for neural repair in the functional genomics era

    NARCIS (Netherlands)

    Verhaagen, J.; van Kesteren, R.E.; Bossers, K.A.; Mac Gillavry, H.D.; Mason, M.R.; Smit, A.B.

    2012-01-01

    A comprehensive understanding of the molecular pathways activated by traumatic neural injury is of major importance for the development of treatments for spinal cord injury (SCI). High-throughput gene expression profiling is a powerful approach to reveal genome-wide changes in gene expression during

  9. Prediction of Repair Work Duration for Gas Transport Systems Based on Small Data Samples

    DEFF Research Database (Denmark)

    Lesnykh, Valery; Litvin, Yuri; Kozin, Igor

    2016-01-01

    Prediction of the duration of a repair and maintenance project of a gas transport system is an important part of planning activities. There exist numerous sources of uncertainties that may result in time overruns possibly leading to multiple negative consequences. Our experience in planning...... this work suggests that accepting the stochastic nature of the project duration is a constructive step towards the preparedness to contingencies and defining penalties for repair companies. To support this approach, one needs to construct probability distributions of the durations of the projects...

  10. A new technique for repair of a dislocated sternoclavicular joint using a sternal tension cable system.

    Science.gov (United States)

    Janson, Jacques T; Rossouw, Gawie J

    2013-02-01

    An unstable anterior or posterior sternoclavicular joint dislocation can cause severe morbidity with poor shoulder movement and strength. These dislocations need to be repaired, which can be challenging. Many different procedures have been described to obtain a stable joint fixation with varying results. We report a new technique for repairing a sternoclavicular joint dislocation by using a figure-of-eight sternal cable system. This procedure is relatively simple and reproducible to create a stable and functional sternoclavicular joint. Copyright © 2013 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

  11. Injecting a liquid bacteria-based repair system to make porous network conrete healed

    NARCIS (Netherlands)

    Sangadji, S.; Wiktor, V.A.C.; Jonkers, H.M.; Schlangen, H.E.J.G.

    2013-01-01

    Bacteria induced calcite precipitation has been proven to be effective in making concrete structure self-healing. In Microlab TU Delft, the concept has been enhanced by developing a liquid bacteria-based concrete repair system. The solution contains calcite precipitating bacteria, nutrients and

  12. Somatic cell and molecular genetics approach to DNA repair and mutagenesis

    International Nuclear Information System (INIS)

    Thompson, L.H.

    1985-01-01

    In the CHO cell line, UV-sensitive mutants representing five genetic complementation groups have been identified. Mutants from each of these groups were shown to be defective in performing the incision step of repair after exposure to UV. The large number of complementation groups of xeroderma pigmentosa mutations has raised the question whether these groups all correspond to single gene loci. The same issue applies to the 5 groups of UV-sensitive CHO mutants. One approach toward answering this question is to localize in the human karyotype the genes that complement the defects in the CHO mutants. Thus, by making CHO/human cell hybrids under the appropriate selective conditions, we have begun to map each of the complementing human genes. The mutation in strain UV20 (Group 2) was complemented by human chromosome 19. Preliminary evidence suggests that UV5 may also be complemented by human chromosome 19 while each of the other 3 groups involves a different human chromosome. Somewhat surprisingly, mutant EM9 is also complemented by a gene on chromosome 19

  13. Scalable Molecular Dynamics for Large Biomolecular Systems

    Directory of Open Access Journals (Sweden)

    Robert K. Brunner

    2000-01-01

    Full Text Available We present an optimized parallelization scheme for molecular dynamics simulations of large biomolecular systems, implemented in the production-quality molecular dynamics program NAMD. With an object-based hybrid force and spatial decomposition scheme, and an aggressive measurement-based predictive load balancing framework, we have attained speeds and speedups that are much higher than any reported in literature so far. The paper first summarizes the broad methodology we are pursuing, and the basic parallelization scheme we used. It then describes the optimizations that were instrumental in increasing performance, and presents performance results on benchmark simulations.

  14. Six types Monte Carlo for estimating the current unavailability of Markov system with dependent repair

    International Nuclear Information System (INIS)

    Xiao Gang; Li Zhizhong

    2004-01-01

    Based on integral equaiton describing the life-history of Markov system, six types of estimators of the current unavailability of Markov system with dependent repair are propounded. Combining with the biased sampling of state transition time of system, six types of Monte Carlo for estimating the current unavailability are given. Two numerical examples are given to deal with the variances and efficiencies of the six types of Monte Carlo methods. (authors)

  15. An artificial neural network for modeling reliability, availability and maintainability of a repairable system

    International Nuclear Information System (INIS)

    Rajpal, P.S.; Shishodia, K.S.; Sekhon, G.S.

    2006-01-01

    The paper explores the application of artificial neural networks to model the behaviour of a complex, repairable system. A composite measure of reliability, availability and maintainability parameters has been proposed for measuring the system performance. The artificial neural network has been trained using past data of a helicopter transportation facility. It is used to simulate behaviour of the facility under various constraints. The insights obtained from results of simulation are useful in formulating strategies for optimal operation of the system

  16. Increasing the Dose of Autologous Chondrocytes Improves Articular Cartilage Repair: Histological and Molecular Study in the Sheep Animal Model.

    Science.gov (United States)

    Guillén-García, Pedro; Rodríguez-Iñigo, Elena; Guillén-Vicente, Isabel; Caballero-Santos, Rosa; Guillén-Vicente, Marta; Abelow, Stephen; Giménez-Gallego, Guillermo; López-Alcorocho, Juan Manuel

    2014-04-01

    We hypothesized that implanting cells in a chondral defect at a density more similar to that of the intact cartilage could induce them to synthesize matrix with the features more similar to that of the uninjured one. We compared the implantation of different doses of chondrocytes: 1 million (n = 5), 5 million (n = 5), or 5 million mesenchymal cells (n = 5) in the femoral condyle of 15 sheep. Tissue generated by microfracture at the trochlea, and normal cartilage from a nearby region, processed as the tissues resulting from the implantation, were used as references. Histological and molecular (expression of type I and II collagens and aggrecan) studies were performed. The features of the cartilage generated by implantation of mesenchymal cells and elicited by microfractures were similar and typical of a poor repair of the articular cartilage (presence of fibrocartilage, high expression of type I collagen and a low mRNA levels of type II collagen and aggrecan). Nevertheless, in the samples obtained from tissues generated by implantation of chondrocytes, hyaline-like cartilage, cell organization, low expression rates of type I collagen and high levels of mRNA corresponding to type II collagen and aggrecan were observed. These histological features, show less variability and are more similar to those of the normal cartilage used as control in the case of 5 million cells implantation than when 1 million cells were used. The implantation of autologous chondrocytes in type I/III collagen membranes at high density could be a promising tool to repair articular cartilage.

  17. Planning of Maintenance and Repair of Complicated Technical Systems

    Directory of Open Access Journals (Sweden)

    N. I. Liseychikov

    2004-01-01

    Full Text Available It is expedient to use mathematical models for substantiation of operational material consumption at maintenance of complicated technical systems. The appropriate tasks have been considered: minimization of operational material consumption; determination of maximum scope of work to be executed while maintaining one system; optimization of operational material consumption while organizing maintenance of a system group; planning of technical maintenance and determination of a number of systems to be maintained. Formalization and solution of the above problems have been accomplished.

  18. The necessity of a theory of biology for tissue engineering: metabolism-repair systems.

    Science.gov (United States)

    Ganguli, Suman; Hunt, C Anthony

    2004-01-01

    Since there is no widely accepted global theory of biology, tissue engineering and bioengineering lack a theoretical understanding of the systems being engineered. By default, tissue engineering operates with a "reductionist" theoretical approach, inherited from traditional engineering of non-living materials. Long term, that approach is inadequate, since it ignores essential aspects of biology. Metabolism-repair systems are a theoretical framework which explicitly represents two "functional" aspects of living organisms: self-repair and self-replication. Since repair and replication are central to tissue engineering, we advance metabolism-repair systems as a potential theoretical framework for tissue engineering. We present an overview of the framework, and indicate directions to pursue for extending it to the context of tissue engineering. We focus on biological networks, both metabolic and cellular, as one such direction. The construction of these networks, in turn, depends on biological protocols. Together these concepts may help point the way to a global theory of biology appropriate for tissue engineering.

  19. DNA repair and its coupling to DNA replication in eukaryotic cells. [UV, x ray

    Energy Technology Data Exchange (ETDEWEB)

    Cleaver, J.E.

    1978-01-01

    This review article with 184 references presents the view that mammalian cells have one major repair system, excision repair, with many branches (nucleotide excision repair, base excision repair, crosslink repair, etc.) and a multiplicity of enzymes. Any particular carcinogen makes a spectrum of damaged sites and each kind of damage may be repaired by one or more branches of excision repair. Excision repair is rarely complete, except at very low doses, and eukaryotic cells survive and replicate DNA despite the presence of unrepaired damage. An alteration in a specific biochemical pathway seen in damaged or mutant cells will not always be the primary consequence of damage or of the biochemical defect of the cells. Detailed kinetic data are required to understand comprehensively the various facets of excision repair and replication. Correlation between molecular events of repair and cytological and cellular changes such as chromosomal damage, mutagenesis, transformation, and carcinogenesis are also rudimentary.

  20. Motorcycle Repair.

    Science.gov (United States)

    Hein, Jim; Bundy, Mike

    This motorcycle repair curriculum guide contains the following ten areas of study: brake systems, clutches, constant mesh transmissions, final drives, suspension, mechanical starting mechanisms, electrical systems, fuel systems, lubrication systems, and overhead camshafts. Each area consists of one or more units of instruction. Each instructional…

  1. Present status of DNA repair mechanisms in uv irradiated yeast taken as a model eukaryotic system

    International Nuclear Information System (INIS)

    Moustacchi, E.; Waters, R.; Heude, M.; Chanet, R.

    1975-01-01

    The repair mechanisms of altered DNA are generally less well understood for eukaryotes than they are for prokaryotes and bacteriophages. For mammalian cell lines cultured in vitro the specific labelling of DNA has allowed the biochemical analysis of some of the steps of the repair processes whereas the determination of their genetic controls is, with a few exceptions, obviously difficult. On the other hand, with fungi and more specifically with yeast taken as a model unicellular eukaryotic system, the genetic approach has been extensively explored: radiosensitive mutants are readily detected and genetically analyzed, double and multiple mutants can be constructed and from their responses to irradiation the number of repair pathways involved can be suggested. The lack of thymidine kinase in these organisms has hampered for a certain time the biochemical analysis of repair. However, the recent isolation of yeast strains capable of taking up and incorporating thymidine 5'-monophosphate into their DNA opens new possibilities for the future. In spite of this difficulty, attempts to measure the induction and removal of uv-induced pyrimidine dimers were performed by several groups during the last three years. The two main repair pathways described for E. coli, i.e., the excision-resynthesis and post-replicative recombinational repair pathways, do exist in yeast. The existence of the former pathway is supported not only by indirect evidence but also by biochemical analysis. The rad 1 and rad 2 mutants for instance have been shown to be blocked in the excision of uv-induced pyrimidine dimers. Other loci are epistatic to rad 1 and rad 2 (rad 3 , rad 4 ) and are likely to act on this excision pathway. The genetic control of the mitochondrial response to a uv treatment involves nuclear genes and mitochondrial determinants

  2. Laboratory Information Systems in Molecular Diagnostics: Why Molecular Diagnostics Data are Different.

    Science.gov (United States)

    Lee, Roy E; Henricks, Walter H; Sirintrapun, Sahussapont J

    2016-03-01

    Molecular diagnostic testing presents new challenges to information management that are yet to be sufficiently addressed by currently available information systems for the molecular laboratory. These challenges relate to unique aspects of molecular genetic testing: molecular test ordering, informed consent issues, diverse specimen types that encompass the full breadth of specimens handled by traditional anatomic and clinical pathology information systems, data structures and data elements specific to molecular testing, varied testing workflows and protocols, diverse instrument outputs, unique needs and requirements of molecular test reporting, and nuances related to the dissemination of molecular pathology test reports. By satisfactorily addressing these needs in molecular test data management, a laboratory information system designed for the unique needs of molecular diagnostics presents a compelling reason to migrate away from the current paper and spreadsheet information management that many molecular laboratories currently use. This paper reviews the issues and challenges of information management in the molecular diagnostics laboratory.

  3. Statistical evaluation of failures and repairs of the V-1 measuring and control system

    International Nuclear Information System (INIS)

    Laurinec, R.; Korec, J.; Mitosinka, J.; Zarnovican, V.

    1984-01-01

    A failure record card system was introduced for evaluating the reliability of the measurement and control equipment of the V-1 nuclear power plant. The SPU-800 microcomputer system is used for recording data on magnetic tape and their transmission to the central data processing department. The data are used for evaluating the reliability of components and circuits and a selection is made of the most failure-prone components, and the causes of failures are evaluated as are failure identification, repair and causes of outages. The system provides monthly, annual and total assessment data since the system was commissioned. The results of the statistical evaluation of failures are used for planning preventive maintenance and for determining optimal repair intervals. (E.S.)

  4. [The correlations between aging of the human body, oxidative stress and reduced efficiency of repair systems].

    Science.gov (United States)

    Michalak, Aleksandra; Krzeszowiak, Jakub; Markiewicz-Górka, Iwona

    2014-12-15

    The article presents an current knowledge overview about the importance of oxidative stress and reduced efficiency of repair processes during the aging process of the human body. Oxidative damage to cellular macromolecules (proteins, lipids, nucleic acids), are formed under the influence of reactive oxygen species (ROS). They are the part of important mechanism which is responsible for the process of aging and the development of many diseases. The most important effects result from DNA damage, due to the mutations formation, which can lead to the development of tumors. However, a well-functioning repair systems (i.a. homologous recombination) remove the damage and prevent harmful changes in the cells. Lipid peroxidation products also cause oxidative modification of nucleic acids (and proteins). Proteins and fats also have repair systems, but much simpler than those responsible for the repair of nucleic acids. Unfortunately, with increasing age, they are more weakened, which contributes to increase numbers of cell damage, and consequently development of diseases specific to old age: cancer, neurodegenerative diseases or atherosclerosis.

  5. Modelling open pit shovel-truck systems using the Machine Repair Model

    Energy Technology Data Exchange (ETDEWEB)

    Krause, A.; Musingwini, C. [CBH Resources Ltd., Sydney, NSW (Australia). Endeaver Mine

    2007-08-15

    Shovel-truck systems for loading and hauling material in open pit mines are now routinely analysed using simulation models or off-the-shelf simulation software packages, which can be very expensive for once-off or occasional use. The simulation models invariably produce different estimations of fleet sizes due to their differing estimations of cycle time. No single model or package can accurately estimate the required fleet size because the fleet operating parameters are characteristically random and dynamic. In order to improve confidence in sizing the fleet for a mining project, at least two estimation models should be used. This paper demonstrates that the Machine Repair Model can be modified and used as a model for estimating truck fleet size in an open pit shovel-truck system. The modified Machine Repair Model is first applied to a virtual open pit mine case study. The results compare favourably to output from other estimation models using the same input parameters for the virtual mine. The modified Machine Repair Model is further applied to an existing open pit coal operation, the Kwagga Section of Optimum Colliery as a case study. Again the results confirm those obtained from the virtual mine case study. It is concluded that the Machine Repair Model can be an affordable model compared to off-the-shelf generic software because it is easily modelled in Microsoft Excel, a software platform that most mines already use.

  6. Formal definition of coherency and computation of minimal cut sequences for binary dynamic and repairable systems

    International Nuclear Information System (INIS)

    Chaux, Pierre-Yves

    2013-01-01

    Preventive risk assessment of a complex system rely on a dynamic models which describe the link between the system failure and the scenarios of failure and repair events from its components. The qualitative analyses of a binary dynamic and repairable system is aiming at computing and analyse the scenarios that lead to the system failure. Since such systems describe a large set of those, only the most representative ones, called Minimal Cut Sequences (MCS), are of interest for the safety engineer. The lack of a formal definition for the MCS has generated multiple definitions either specific to a given model (and thus not generic) or informal. This work proposes i) a formal framework and definition for the MCS while staying independent of the reliability model used, ii) the methodology to compute them using property extracted from their formal definition, iii) an extension of the formal framework for multi-states components in order to perform the qualitative analyses of Boolean logic Driven Markov Processes (BDMP) models. Under the hypothesis that the scenarios implicitly described by any reliability model can always be represented by a finite automaton, this work is defining the coherency for dynamic and repairable systems as the way to give a minimal representation of all scenarios that are leading to the system failure. (author)

  7. RNA damage in biological conflicts and the diversity of responding RNA repair systems

    Science.gov (United States)

    Burroughs, A. Maxwell; Aravind, L.

    2016-01-01

    RNA is targeted in biological conflicts by enzymatic toxins or effectors. A vast diversity of systems which repair or ‘heal’ this damage has only recently become apparent. Here, we summarize the known effectors, their modes of action, and RNA targets before surveying the diverse systems which counter this damage from a comparative genomics viewpoint. RNA-repair systems show a modular organization with extensive shuffling and displacement of the constituent domains; however, a general ‘syntax’ is strongly maintained whereby systems typically contain: a RNA ligase (either ATP-grasp or RtcB superfamilies), nucleotidyltransferases, enzymes modifying RNA-termini for ligation (phosphatases and kinases) or protection (methylases), and scaffold or cofactor proteins. We highlight poorly-understood or previously-uncharacterized repair systems and components, e.g. potential scaffolding cofactors (Rot/TROVE and SPFH/Band-7 modules) with their respective cognate non-coding RNAs (YRNAs and a novel tRNA-like molecule) and a novel nucleotidyltransferase associating with diverse ligases. These systems have been extensively disseminated by lateral transfer between distant prokaryotic and microbial eukaryotic lineages consistent with intense inter-organismal conflict. Components have also often been ‘institutionalized’ for non-conflict roles, e.g. in RNA-splicing and in RNAi systems (e.g. in kinetoplastids) which combine a distinct family of RNA-acting prim-pol domains with DICER-like proteins. PMID:27536007

  8. High sensitivity optical molecular imaging system

    Science.gov (United States)

    An, Yu; Yuan, Gao; Huang, Chao; Jiang, Shixin; Zhang, Peng; Wang, Kun; Tian, Jie

    2018-02-01

    Optical Molecular Imaging (OMI) has the advantages of high sensitivity, low cost and ease of use. By labeling the regions of interest with fluorescent or bioluminescence probes, OMI can noninvasively obtain the distribution of the probes in vivo, which play the key role in cancer research, pharmacokinetics and other biological studies. In preclinical and clinical application, the image depth, resolution and sensitivity are the key factors for researchers to use OMI. In this paper, we report a high sensitivity optical molecular imaging system developed by our group, which can improve the imaging depth in phantom to nearly 5cm, high resolution at 2cm depth, and high image sensitivity. To validate the performance of the system, special designed phantom experiments and weak light detection experiment were implemented. The results shows that cooperated with high performance electron-multiplying charge coupled device (EMCCD) camera, precision design of light path system and high efficient image techniques, our OMI system can simultaneously collect the light-emitted signals generated by fluorescence molecular imaging, bioluminescence imaging, Cherenkov luminance and other optical imaging modality, and observe the internal distribution of light-emitting agents fast and accurately.

  9. Generalized renewal process for repairable systems based on finite Weibull mixture

    International Nuclear Information System (INIS)

    Veber, B.; Nagode, M.; Fajdiga, M.

    2008-01-01

    Repairable systems can be brought to one of possible states following a repair. These states are: 'as good as new', 'as bad as old' and 'better than old but worse than new'. The probabilistic models traditionally used to estimate the expected number of failures account for the first two states, but they do not properly apply to the last one, which is more realistic in practice. In this paper, a probabilistic model that is applicable to all of the three after-repair states, called generalized renewal process (GRP), is applied. Simplistically, GRP addresses the repair assumption by introducing the concept of virtual age into the stochastic point processes to enable them to represent the full spectrum of repair assumptions. The shape of measured or design life distributions of systems can vary considerably, and therefore frequently cannot be approximated by simple distribution functions. The scope of the paper is to prove that a finite Weibull mixture, with positive component weights only, can be used as underlying distribution of the time to first failure (TTFF) of the GRP model, on condition that the unknown parameters can be estimated. To support the main idea, three examples are presented. In order to estimate the unknown parameters of the GRP model with m-fold Weibull mixture, the EM algorithm is applied. The GRP model with m mixture components distributions is compared to the standard GRP model based on two-parameter Weibull distribution by calculating the expected number of failures. It can be concluded that the suggested GRP model with Weibull mixture with an arbitrary but finite number of components is suitable for predicting failures based on the past performance of the system

  10. A decision dependent stochastic process model for repairable systems with applications

    Directory of Open Access Journals (Sweden)

    Paul F. Zantek

    2015-12-01

    This paper mathematically formalizes the notion of how management actions impact the functioning of a repairable system over time by developing a new stochastic process model for such systems. The proposed model is illustrated using both simulated and real data. The proposed model compares favorably to other models for well-known data on Boeing airplanes. The model is further illustrated and compared to other models on failure time and maintenance data stemming from the South Texas Project nuclear power plant.

  11. Multi-echelon Repair Inventory Systems: Select Issues in Modular Electronic Equipment

    OpenAIRE

    Amik Garg; S. G. Deshmukh

    2010-01-01

    Flow of modules/printed circuit boards (PCBs) in a multi-echelon repair inventory system pertaining to modular electronic equipment for large maintenance organisations having large inventory in range and depth, like defence has been critically examined using a case study. Desirable features of the proposed system are identified and a general framework suggested for examining its feasibility and implementation in an organisation. An analytical model with an objective to reduce number of echelo...

  12. Non-periodic preventive maintenance with reliability thresholds for complex repairable systems

    International Nuclear Information System (INIS)

    Lin, Zu-Liang; Huang, Yeu-Shiang; Fang, Chih-Chiang

    2015-01-01

    In general, a non-periodic condition-based PM policy with different condition variables is often more effective than a periodic age-based policy for deteriorating complex repairable systems. In this study, system reliability is estimated and used as the condition variable, and three reliability-based PM models are then developed with consideration of different scenarios which can assist in evaluating the maintenance cost for each scenario. The proposed approach provides the optimal reliability thresholds and PM schedules in advance by which the system availability and quality can be ensured and the organizational resources can be well prepared and managed. The results of the sensitivity anlysis indicate that PM activities performed at a high reliability threshold can not only significantly improve the system availability but also efficiently extend the system lifetime, although such a PM strategy is more costly than that for a low reliabiltiy threshold. The optimal reliability threshold increases along with the number of PM activities to prevent future breakdowns caused by severe deterioration, and thus substantially reduces repair costs. - Highlights: • The PM problems for repairable deteriorating systems are formulated. • The structural properties of the proposed PM models are investigated. • The corresponding algorithms to find the optimal PM strategies are provided. • Imperfect PM activities are allowed to reduce the occurences of breakdowns. • Provide managers with insights about the critical factors in the planning stage

  13. Reliability Analysis of 6-Component Star Markov Repairable System with Spatial Dependence

    Directory of Open Access Journals (Sweden)

    Liying Wang

    2017-01-01

    Full Text Available Star repairable systems with spatial dependence consist of a center component and several peripheral components. The peripheral components are arranged around the center component, and the performance of each component depends on its spatial “neighbors.” Vector-Markov process is adapted to describe the performance of the system. The state space and transition rate matrix corresponding to the 6-component star Markov repairable system with spatial dependence are presented via probability analysis method. Several reliability indices, such as the availability, the probabilities of visiting the safety, the degradation, the alert, and the failed state sets, are obtained by Laplace transform method and a numerical example is provided to illustrate the results.

  14. Development of laser cladding system to repair wall thinning of 1-inch heat exchanger tube

    International Nuclear Information System (INIS)

    Terada, Takaya

    2013-01-01

    We developed a laser cladding system to repair the inner wall wastage of heat exchanger tubes. Our system, which is designed to repair thinning tube walls within 100 mm from the edge of a heat exchanger tube, consists of a fiber laser, a composite-type optical fiberscope, a coupling device, a laser processing head, and a wire-feeding device. All of these components were reconfigured from the technologies of FBR maintenance. The laser processing head, which has a 15-mm outer diameter, was designed to be inserted into a 1-inch heat exchanger tube. We mounted a heatproof broadband mirror for laser cladding and fiberscope observation with visible light inside the laser processing head. The wire-feeding device continuously supplied 0.4-mm wire to the laser irradiation spot with variable feeding speeds from 0.5 to 20 mm/s. We are planning to apply our proposed system to the maintenance of aging industrial plants. (author)

  15. A shock and wear system under environmental conditions subject to internal failures, repair, and replacement

    International Nuclear Information System (INIS)

    Montoro-Cazorla, Delia; Pérez-Ocón, Rafael

    2012-01-01

    A system in a random environment is considered. The influence of the external conditions is governed by a Markovian arrival process. The internal structure of failure and repair are governed by phase-type distributions. The maintenance is performed by policy N. Under these assumptions, the Markov process governing the system is constructed, and it is studied in transient and stationary regime, calculating the availability and the rate of occurrence of failures. The renewal process due to the replacements of the system is studied, and expressions for the number of replacements and for the number of repairs between replacements are calculated. This paper extends other previously published since it incorporates a shock arrival process with dependence among the interarrival times and the renewal process associated to the replacements. A numerical application illustrates the calculations.

  16. Rare event simulation for highly dependable systems with fast repairs

    NARCIS (Netherlands)

    Reijsbergen, D.P.; de Boer, Pieter-Tjerk; Scheinhardt, Willem R.W.; Haverkort, Boudewijn R.H.M.

    2010-01-01

    Stochastic model checking has been used recently to assess, among others, dependability measures for a variety of systems. However, the employed numerical methods, as, e.g., supported by model checking tools such as PRISM and MRMC, suffer from the state-space explosion problem. The main alternative

  17. Rare event simulation for highly dependable systems with fast repairs

    NARCIS (Netherlands)

    Reijsbergen, D.P.; de Boer, Pieter-Tjerk; Scheinhardt, Willem R.W.; Haverkort, Boudewijn R.H.M.

    Probabilistic model checking has been used recently to assess, among others, dependability measures for a variety of systems. However, the numerical methods employed, such as those supported by model checking tools such as PRISM and MRMC, suffer from the state-space explosion problem. The main

  18. Automated TIG welding system with visual sensor for repairing nuclear plants

    International Nuclear Information System (INIS)

    Inoue, Katsunori; Watanabe, Hiroshi; Kondoh, Yoshihide.

    1986-01-01

    An automated TIG welding system has been developed. This system is to be used for repairing nuclear plants, whose work environment is highly radioactive, so should have the automatic self control function and the remote controllable function. For this purpose, the visual sensor, a TV camera and an image processor, is installed and the image processing technique is applied to the all-position TIG welding system. In this system, all controls are made with microprocessors and every necessary information is displayed on the screen of the remote control unit. The excellent performance was obtained as the application of this system to the practical field. (author)

  19. DOE contractors' workshop: Cellular and molecular aspects of radiation induced DNA damage and repair

    Energy Technology Data Exchange (ETDEWEB)

    1987-01-01

    For four decades the US Department of Energy and its predecessors have been the lead federal agency in supporting radiation biology research. Over the years emphasis in this program has gradually shifted from dose-effect studies on animals to research on the effects of radiations of various qualities on cells and molecules. Mechanistic studies on the action of radiation at the subcellular level are few in number and there is a need for more research in this area if we are to gain a better understanding of how radiation affects living cells. The intent of this workshop was to bring together DOE contractors and grantees who are investigating the effects of radiation at the cellular and molecular levels. The aims were to foster the exchange of information on research projects and experimental results, promote collaborative research efforts, and obtain an overview of research currently supported by the Health Effects Research Division of the Office of Health and Environmental Research. The latter is needed by the Office for program planning purposes. This report on the workshop which took place in Albuquerque, New Mexico on March 10-11, 1987, includes an overview with future research recommendations, extended abstracts of the plenary presentations, shorter abstracts of each poster presentation, a workshop agenda and the names and addresses of the attendees.

  20. DOE contractors' workshop: Cellular and molecular aspects of radiation induced DNA damage and repair

    International Nuclear Information System (INIS)

    1987-01-01

    For four decades the US Department of Energy and its predecessors have been the lead federal agency in supporting radiation biology research. Over the years emphasis in this program has gradually shifted from dose-effect studies on animals to research on the effects of radiations of various qualities on cells and molecules. Mechanistic studies on the action of radiation at the subcellular level are few in number and there is a need for more research in this area if we are to gain a better understanding of how radiation affects living cells. The intent of this workshop was to bring together DOE contractors and grantees who are investigating the effects of radiation at the cellular and molecular levels. The aims were to foster the exchange of information on research projects and experimental results, promote collaborative research efforts, and obtain an overview of research currently supported by the Health Effects Research Division of the Office of Health and Environmental Research. The latter is needed by the Office for program planning purposes. This report on the workshop which took place in Albuquerque, New Mexico on March 10-11, 1987, includes an overview with future research recommendations, extended abstracts of the plenary presentations, shorter abstracts of each poster presentation, a workshop agenda and the names and addresses of the attendees

  1. Diabetes mellitus and ischemic diseases: molecular mechanisms of vascular repair dysfunction.

    Science.gov (United States)

    Howangyin, Kiave Yune; Silvestre, Jean-Sébastien

    2014-06-01

    In patients with diabetes mellitus, the ability of ischemic tissue to synchronize the molecular and cellular events leading to restoration of tissue perfusion in response to the atherosclerotic occlusion of a patent artery is markedly impaired. As a consequence, adverse tissue remodeling and the extent of ischemic injury are intensified, leading to increased morbidity and mortality. Growing evidence from preclinical and clinical studies has implicated alterations in hypoxia-inducible factor 1 levels in the abrogation of proangiogenic pathways, including vascular endothelial growth factor A/phosphoinositide 3' kinase/AKT/endothelial nitric oxide synthase and in the activation of antiangiogenic signals characterized by accumulation of advanced glycation end products, reactive oxygen species overproduction, and endoplasmic reticulum stress. In addition, the diabetic milieu shows a switch toward proinflammatory antiregenerative pathways. Finally, the mobilization, subsequent recruitment, and the proangiogenic potential of the different subsets of angiogenesis-promoting bone marrow-derived cells are markedly impaired in the diabetic environment. In this review, we will give an overview of the current understanding on the signaling molecules contributing to the diabetes mellitus-induced impairment of postischemic revascularization mainly in the setting of myocardial infarction or critical limb ischemia. © 2014 American Heart Association, Inc.

  2. Nuclear molecular structure in heavy mass systems

    International Nuclear Information System (INIS)

    Arctaedius, T.; Bargholtz, C.

    1989-04-01

    A study is made of nuclear molecular configurations involving one heavy mass partner. The stability of these configurations to mass flow and to fission is investigated as well as their population in fusion reactions. It is concluded that shell effects in combination with the effects of angular momentum may be important in stabilizing certain configurations. A possible relation of these configurations to the so called superdeformed states is pointed out. The spectrum of rotational and vibrational trasitions within molecular configurations is investigated. For sufficiently mass-asymmetric systems the engergies of vibrational transitions are comparable to the neutron separation energy. Gamma radiation from such transitions may then be observable above the background of statistical transitions. The gamma spectrum and the directional distribution of the radioation following fusion reactions with 12 C and 16 O are calculated. (authors)

  3. Molecular Simulation of Reacting Systems; TOPICAL

    International Nuclear Information System (INIS)

    THOMPSON, AIDAN P.

    2002-01-01

    The final report for a Laboratory Directed Research and Development project entitled, Molecular Simulation of Reacting Systems is presented. It describes efforts to incorporate chemical reaction events into the LAMMPS massively parallel molecular dynamics code. This was accomplished using a scheme in which several classes of reactions are allowed to occur in a probabilistic fashion at specified times during the MD simulation. Three classes of reaction were implemented: addition, chain transfer and scission. A fully parallel implementation was achieved using a checkerboarding scheme, which avoids conflicts due to reactions occurring on neighboring processors. The observed chemical evolution is independent of the number of processors used. The code was applied to two test applications: irreversible linear polymerization and thermal degradation chemistry

  4. Uncertain multiobjective redundancy allocation problem of repairable systems based on artificial bee colony algorithm

    Institute of Scientific and Technical Information of China (English)

    Guo Jiansheng; Wang Zutong; Zheng Mingfa; Wang Ying

    2014-01-01

    Based on the uncertainty theory, this paper is devoted to the redundancy allocation problem in repairable parallel-series systems with uncertain factors, where the failure rate, repair rate and other relative coefficients involved are considered as uncertain variables. The availability of the system and the corresponding designing cost are considered as two optimization objectives. A crisp multiobjective optimization formulation is presented on the basis of uncertainty theory to solve this resultant problem. For solving this problem efficiently, a new multiobjective artificial bee colony algorithm is proposed to search the Pareto efficient set, which introduces rank value and crowding distance in the greedy selection strategy, applies fast non-dominated sort procedure in the exploitation search and inserts tournament selection in the onlooker bee phase. It shows that the proposed algorithm outperforms NSGA-II greatly and can solve multiobjective redundancy allocation problem efficiently. Finally, a numerical example is provided to illustrate this approach.

  5. Molecular ecology of anaerobic reactor systems

    DEFF Research Database (Denmark)

    Hofman-Bang, H. Jacob Peider; Zheng, D.; Westermann, Peter

    2003-01-01

    Anaerobic reactor systems are essential for the treatment of solid and liquid wastes and constitute a core facility in many waste treatment plants. Although much is known about the basic metabolism in different types of anaerobic reactors, little is known about the microbes responsible for these ......Anaerobic reactor systems are essential for the treatment of solid and liquid wastes and constitute a core facility in many waste treatment plants. Although much is known about the basic metabolism in different types of anaerobic reactors, little is known about the microbes responsible...... to the abundance of each microbe in anaerobic reactor systems by rRNA probing. This chapter focuses on various molecular techniques employed and problems encountered when elucidating the microbial ecology of anaerobic reactor systems. Methods such as quantitative dot blot/fluorescence in-situ probing using various...

  6. Recommendations for optimised repair welding operations in steam systems exposed to creep; Rekommendationer foer optimering av svetsreparationer i kryppaakaenda aangsystem

    Energy Technology Data Exchange (ETDEWEB)

    Storesund, Jan; Samuelson, Aake; Klasen, Bjoern; Jensen, Carsten

    2002-03-01

    Recommendations for optimised repair welding in creep exposed steam systems have been produced on basis of different parts of the project which involve a literature survey, case studies, metallographical investigations and finite element simulations. The separate parts are compiled in the present report where the results also are coupled to each other. Two of the project parts are reported in appendices in the present report and the other ones in three separate work reports. The studies have shown evidence of the complexity associated with repair welding and many alternatives may be offered for a given situation. The importance of the factors which may influence the life time of the repair have been investigated and are described in order to facilitate the decision-making process for the given situation. From the obtained results there are also more general recommendations to be given: Make sure that system stresses not are acting at the repair. Avoid welding methods that could result in strongly creep soft HAZs. Select a weld metal for the repair which is slightly creep hard compared to the remaining aged material. Selection of a wide and 'medium' deep excavation geometry as well as a repair around the whole circumference is to be preferred. Repairs of welds that not include excavation of the whole width of the original weld should be avoided. Replica testing is recommended in addition to the common practice in the quality and condition-monitoring control of the repair.

  7. A systems approach to inventory management of repairables in the Navy

    OpenAIRE

    Apple, Chris Leon

    1985-01-01

    Approved for public release; distribution is unlimited This thesis develops an inventory model for repairable items which integrates the shipboard protection level into the wholesale stock level computations. It uses mean supply response time (MSRT) as its measure of effectiveness and provides methods for computing either the required wholesale stock level given a MSRT goal or for minimizing the system MSRT subject to budgetary constraints. Examples are provided which demons...

  8. Novel Combinatory Approaches to Repair Visual System after Optic Nerve Damage

    Science.gov (United States)

    2014-09-01

    Novel Combinatory Approaches to Repair Visual System After Optic Nerve Damage 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6...biological functions such as metabolism, growth, cell cycle, and survival ( Cardone et al., 1998; Diehl, Cheng, Roussel, & Sherr, 1998; Hers, Vincent...of injured adult sensory neurons. The Journal of Neuroscience, 21, 7161–7170. Cardone , M. H., Roy, N., Stennicke, H. R., Salvesen, G. S., Franke, T. F

  9. An application of modulated poisson processes to the reliability analysis of repairable systems

    Energy Technology Data Exchange (ETDEWEB)

    Saldanha, Pedro L.C. [Comissao Nacional de Energia Nuclear (CNEN), Rio de Janeiro, RJ (Brazil). Coordenacao de Reatores]. E-mail: saldanha@cnen.gov.br; Melo, P.F. Frutuoso e [Universidade Federal, Rio de Janeiro, RJ (Brazil). Coordenacao dos Programas de Pos-graduacao de Engenharia. Programa de Engenharia Nuclear]. E-mail: frutuoso@con.ufrj.br; Noriega, Hector C. [Universidad Austral de Chile (UACh), Valdivia (Chile). Faculdad de Ciencias de la Ingeniaria]. E-mail: hnoriega@uach.cl

    2005-07-01

    This paper discusses the application of the modulated power law process (MPLP) model to the rate of occurrence of failures of active repairable systems in reliability engineering. Traditionally, two ways of modeling repairable systems, in what concerns maintenance policies, are: a pessimistic approach (non-homogeneous process - NHPP), and a very optimistic approach (renewal processes - RP). It is important to build a generalized model that might consider characteristics and properties both of the NHPP and of the RP models as particular cases. In practice, by considering the pattern of times between failures, the MPLP appears to be more realistic to represent the occurrence of failures of repairable systems in order to define whether they can be modeled by a homogeneous or a non-homogeneous process. The study has shown that the model can be used to make decisions concerning the evaluation of the qualified life of plant equipment. By controlling and monitoring two of the three parameters of the MPLP model during the equipment operation, it is possible to check whether and how the equipment is following the basis of its qualification process, and so identify how the effects of time, degradation and operation modes are influencing the equipment performance. The discussion is illustrated by an application to the service water pumps of a typical PWR plant. (author)

  10. Microelectromechanical systems integrating molecular spin crossover actuators

    Energy Technology Data Exchange (ETDEWEB)

    Manrique-Juarez, Maria D. [LCC, CNRS and Université de Toulouse, UPS, INP, F-31077 Toulouse (France); LAAS, CNRS and Université de Toulouse, INSA, UPS, F-31077 Toulouse (France); Rat, Sylvain; Salmon, Lionel; Molnár, Gábor; Bousseksou, Azzedine, E-mail: liviu.nicu@laas.fr, E-mail: azzedine.bousseksou@lcc-toulouse.fr [LCC, CNRS and Université de Toulouse, UPS, INP, F-31077 Toulouse (France); Mathieu, Fabrice; Saya, Daisuke; Séguy, Isabelle; Leïchlé, Thierry; Nicu, Liviu, E-mail: liviu.nicu@laas.fr, E-mail: azzedine.bousseksou@lcc-toulouse.fr [LAAS, CNRS and Université de Toulouse, INSA, UPS, F-31077 Toulouse (France)

    2016-08-08

    Silicon MEMS cantilevers coated with a 200 nm thin layer of the molecular spin crossover complex [Fe(H{sub 2}B(pz){sub 2}){sub 2}(phen)] (H{sub 2}B(pz){sub 2} = dihydrobis(pyrazolyl)borate and phen = 1,10-phenantroline) were actuated using an external magnetic field and their resonance frequency was tracked by means of integrated piezoresistive detection. The light-induced spin-state switching of the molecules from the ground low spin to the metastable high spin state at 10 K led to a well-reproducible shift of the cantilever's resonance frequency (Δf{sub r} = −0.52 Hz). Control experiments at different temperatures using coated as well as uncoated devices along with simple calculations support the assignment of this effect to the spin transition. This latter translates into changes in mechanical behavior of the cantilever due to the strong spin-state/lattice coupling. A guideline for the optimization of device parameters is proposed so as to efficiently harness molecular scale movements for large-scale mechanical work, thus paving the road for nanoelectromechanical systems (NEMS) actuators based on molecular materials.

  11. The Optical Bichromatic Force in Molecular Systems

    Science.gov (United States)

    Aldridge, Leland; Galica, Scott; Eyler, E. E.

    2015-05-01

    The optical bichromatic force has been demonstrated to be useful for slowing atomic beams much more rapidly than radiative forces. Through numerical simulations, we examine several aspects of applying the bichromatic force to molecular beams. One is the unavoidable existence of out-of-system radiative decay, requiring one or more repumping beams. We find that the average deceleration varies strongly with the repumping intensity, but when using optimal parameters, the force approaches the limiting value allowed by population statistics. Another consideration is the effect of fine and hyperfine structure. We examine a simplified multlevel model based on the B X transition in calcium monofluoride. To circumvent optical pumping into coherent dark states, we include two possible schemes: (1) a skewed dc magnetic field, and (2) rapid optical polarization switching. Our results indicate that the bichromatic force remains a viable option for creating large forces in molecular beams, with a reduction in the peak force by approximately an order of magnitude compared to a two-level atom, but little effect on the velocity range over which the force is effective. We also describe our progress towards experimental tests of the bichromatic force on a molecular beam of CaF. Supported by the National Science Foundation.

  12. Molecular marker systems for Oenothera genetics.

    Science.gov (United States)

    Rauwolf, Uwe; Golczyk, Hieronim; Meurer, Jörg; Herrmann, Reinhold G; Greiner, Stephan

    2008-11-01

    The genus Oenothera has an outstanding scientific tradition. It has been a model for studying aspects of chromosome evolution and speciation, including the impact of plastid nuclear co-evolution. A large collection of strains analyzed during a century of experimental work and unique genetic possibilities allow the exchange of genetically definable plastids, individual or multiple chromosomes, and/or entire haploid genomes (Renner complexes) between species. However, molecular genetic approaches for the genus are largely lacking. In this study, we describe the development of efficient PCR-based marker systems for both the nuclear genome and the plastome. They allow distinguishing individual chromosomes, Renner complexes, plastomes, and subplastomes. We demonstrate their application by monitoring interspecific exchanges of genomes, chromosome pairs, and/or plastids during crossing programs, e.g., to produce plastome-genome incompatible hybrids. Using an appropriate partial permanent translocation heterozygous hybrid, linkage group 7 of the molecular map could be assigned to chromosome 9.8 of the classical Oenothera map. Finally, we provide the first direct molecular evidence that homologous recombination and free segregation of chromosomes in permanent translocation heterozygous strains is suppressed.

  13. DNA Repair Gene (XRCC1 Polymorphism (Arg399Gln Associated with Schizophrenia in South Indian Population: A Genotypic and Molecular Dynamics Study.

    Directory of Open Access Journals (Sweden)

    S P Sujitha

    Full Text Available This paper depicts the first report from an Indian population on the association between the variant Arg399Gln of XRCC1 locus in the DNA repair system and schizophrenia, the debilitating disease that affects 1% of the world population. Genotypic analysis of a total of 523 subjects (260 patients and 263 controls revealed an overwhelming presence of Gln399Gln in the case subjects against the controls (P < 0.0068, indicating significant level of association of this nsSNP with schizophrenia; the Gln399 allele frequency was also perceptibly more in cases than in controls (p < 0.003; OR = 1.448. The results of the genotypic studies were further validated using pathogenicity and stability prediction analysis employing computational tools [I-Mutant Suite, iStable, PolyPhen2, SNAP, and PROVEAN], with a view toassess the magnitude of deleteriousness of the mutation. The pathogenicity analysis reveals that the nsSNP could be deleterious inasmuch as it could affect the functionality of the gene, and interfere with protein function. Molecular dynamics simulation of 60ns was performed using GROMACS to analyse structural change due to a mutation (Arg399Gln that was never examined before. RMSD, RMSF, hydrogen bonds, radius of gyration and SASA analysis showedthe existence of asignificant difference between the native and the mutant protein. The present study gives astrong indication that the XRCC1 locus deserves serious attention, as it could be a potential candidatecontributing to the etio-pathogenesis of the disease.

  14. A New Approach for Analyzing the Reliability of the Repair Facility in a Series System with Vacations

    Directory of Open Access Journals (Sweden)

    Renbin Liu

    2012-01-01

    Full Text Available Based on the renewal process theory we develop a decomposition method to analyze the reliability of the repair facility in an n-unit series system with vacations. Using this approach, we study the unavailability and the mean replacement number during (0,t] of the repair facility. The method proposed in this work is novel and concise, which can make us see clearly the structures of the facility indices of a series system with an unreliable repair facility, two convolution relations. Special cases and numerical examples are given to show the validity of our method.

  15. Interactions of radiation repair systems in escherichia colt with antineoplastic anthracyclines

    International Nuclear Information System (INIS)

    Kacinski, B.M.; Rupp, W.D.

    1984-01-01

    The authors have studied the interactions of several anthracylines with the UVR DN*a repair system of E. coli. The authors found that doxorubicin is quite toxic for uvr- but not for uvr+strains. They also found that exposure of cells carrying a multicopy plasmid to this agent yielded plasmid DNA molecules with lesions which were recognized and cleaved by purified E. coli UVRABC DNA repair endonuclease. A derivative of doxorubicin was not measurably toxic for either uvr+ or uvr- strains but nevertheless produced lesions which were substrates for the UVRABC endonuclease. The authors propose that anthracycline toxicity in uvr- E. coli may correlate with clinical toxicity while anthracylcine antineopolastic activity may correlate with their ability to produce UVRABC endonuclease-sensitive DNA damage

  16. Bioactive Molecule-loaded Drug Delivery Systems to Optimize Bone Tissue Repair.

    Science.gov (United States)

    Oshiro, Joao Augusto; Sato, Mariana Rillo; Scardueli, Cassio Rocha; Lopes de Oliveira, Guilherme Jose Pimentel; Abucafy, Marina Paiva; Chorilli, Marlus

    2017-01-01

    Bioactive molecules such as peptides and proteins can optimize the repair of bone tissue; however, the results are often unpredictable when administered alone, owing to their short biological half-life and instability. Thus, the development of bioactive molecule-loaded drug delivery systems (DDS) to repair bone tissue has been the subject of intense research. DDS can optimize the repair of bone tissue owing to their physicochemical properties, which improve cellular interactions and enable the incorporation and prolonged release of bioactive molecules. These characteristics are fundamental to favor bone tissue homeostasis, since the biological activity of these factors depends on how accessible they are to the cell. Considering the importance of these DDS, this review aims to present relevant information on DDS when loaded with osteogenic growth peptide and bone morphogenetic protein. These are bioactive molecules that are capable of modulating the differentiation and proliferation of mesenchymal cells in bone tissue cells. Moreover, we will present different approaches using these peptide and protein-loaded DDS, such as synthetic membranes and scaffolds for bone regeneration, synthetic grafts, bone cements, liposomes, and micelles, which aim at improving the therapeutic effectiveness, and we will compare their advantages with commercial systems. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  17. THE WORK SIMULATION OF FLOW RATE FOR CARRIAGES' REPAIR AS A MULTIPHASE, MULTIPLEX AND MULTIDISCIPLINARY SYSTEM OF MASS SERVICE

    Directory of Open Access Journals (Sweden)

    V. V. Myamlin

    2011-04-01

    Full Text Available The algorithm of computer simulation of the flexible flow for repair of cars as a multiphase polychannel manyobject queuing system is presented. The basic operators of the model are given and their work is described.

  18. Space Shuttle Thermal Protection System Repair Flight Experiment Induced Contamination Impacts

    Science.gov (United States)

    Smith, Kendall A.; Soares, Carlos E.; Mikatarian, Ron; Schmidl, Danny; Campbell, Colin; Koontz, Steven; Engle, Michael; McCroskey, Doug; Garrett, Jeff

    2006-01-01

    NASA s activities to prepare for Flight LF1 (STS-114) included development of a method to repair the Thermal Protection System (TPS) of the Orbiter s leading edge should it be damaged during ascent by impacts from foam, ice, etc . Reinforced Carbon-Carbon (RCC) is used for the leading edge TPS. The repair material that was developed is named Non- Oxide Adhesive eXperimental (NOAX). NOAX is an uncured adhesive material that acts as an ablative repair material. NOAX completes curing during the Orbiter s descent. The Thermal Protection System (TPS) Detailed Test Objective 848 (DTO 848) performed on Flight LF1 (STS-114) characterized the working life, porosity void size in a micro-gravity environment, and the on-orbit performance of the repairs to pre-damaged samples. DTO 848 is also scheduled for Flight ULF1.1 (STS-121) for further characterization of NOAX on-orbit performance. Due to the high material outgassing rates of the NOAX material and concerns with contamination impacts to optically sensitive surfaces, ASTM E 1559 outgassing tests were performed to determine NOAX condensable outgassing rates as a function of time and temperature. Sensitive surfaces of concern include the Extravehicular Mobility Unit (EMU) visor, cameras, and other sensors in proximity to the experiment during the initial time after application. This paper discusses NOAX outgassing characteristics, how the amount of deposition on optically sensitive surfaces while the NOAX is being manipulated on the pre-damaged RCC samples was determined by analysis, and how flight rules were developed to protect those optically sensitive surfaces from excessive contamination where necessary.

  19. Molecular Imaging with Activatable Reporter Systems

    Directory of Open Access Journals (Sweden)

    Gang Niu, Xiaoyuan Chen

    2012-01-01

    Full Text Available Molecular imaging is a newly emerged multiple disciplinary field that aims to visualize, characterize and quantitatively measure biological processes at cellular and molecular levels in humans and other living systems. A reporter gene is a piece of DNA encoding reporter protein, which presents as a readily measurable phenotype that can be distinguished easily from the background of endogenous protein. After being transferred into cells of organ systems (transgenes, the reporter gene can be utilized to visualize transcriptional and posttranscriptional regulation of gene expression, protein-protein interactions, or trafficking of proteins or cells in living subjects. Herein, we review previous classification of reporter genes and regroup the reporter gene based imaging as basic, inducible and activatable, based on the regulation of reporter gene transcription and post-translational modification of reporter proteins. We then focus on activatable reporters, in which the signal can be activated at the posttranslational level for visualizing protein-protein interactions, protein phosphorylation or tertiary structure changes. The applications of several types of activatable reporters will also be summarized. We conclude that activatable reporter imaging can benefit both basic biomedical research and drug development.

  20. Energy transformation in molecular electronic systems

    International Nuclear Information System (INIS)

    Kasha, M.

    1985-01-01

    Our new optical pumping spectroscopy (steady state, and double-laser pulse) allows the production and study of the unstable rare tautomer in its ground and excited states, including picosecond dynamic studies. Molecules under study here included 7-azaindole (model for biological purines), 3-hydroxyflavone (model for plant flavones), lumichrome, and other heterocyclics. New detailed molecular mechanisms for proton transfer are derived, especially with catalytic assisting molecules. A new proton-transfer laser of extraordinary efficiency has become a side dividend, possibly worth of industrial development. The excited and highly reactive singlet molecular oxygen species 1 Δ/sub g/) has proven to be ubiquitous in chemical peroxide systems and in physically excited sensitizer-oxygen systems. Hyperbaric oxygen mechanisms in biology probably involve singlet oxygen. We have undertaken a spectroscopic study of tris - dibenzoylmethane chelates of Al, Gd, Eu, and Yb trivalent ions. These chelates offer a variety of electronic behaviors, from Z-effects on π-electron spin-orbital coupling (Al, Gd) to Weissman intramolecular energy transfer to 4f mestable levels (Eu, Gd). Elegant new spectroscopic resolution at 77K permits separation of tautomeric, parasitic self-absorption, dissociation, and cage effects to be resolved. 18 refs., 4 figs

  1. Systems Pharmacology in Small Molecular Drug Discovery

    Directory of Open Access Journals (Sweden)

    Wei Zhou

    2016-02-01

    Full Text Available Drug discovery is a risky, costly and time-consuming process depending on multidisciplinary methods to create safe and effective medicines. Although considerable progress has been made by high-throughput screening methods in drug design, the cost of developing contemporary approved drugs did not match that in the past decade. The major reason is the late-stage clinical failures in Phases II and III because of the complicated interactions between drug-specific, human body and environmental aspects affecting the safety and efficacy of a drug. There is a growing hope that systems-level consideration may provide a new perspective to overcome such current difficulties of drug discovery and development. The systems pharmacology method emerged as a holistic approach and has attracted more and more attention recently. The applications of systems pharmacology not only provide the pharmacodynamic evaluation and target identification of drug molecules, but also give a systems-level of understanding the interaction mechanism between drugs and complex disease. Therefore, the present review is an attempt to introduce how holistic systems pharmacology that integrated in silico ADME/T (i.e., absorption, distribution, metabolism, excretion and toxicity, target fishing and network pharmacology facilitates the discovery of small molecular drugs at the system level.

  2. Calcium Carbonate Formation in Water Distribution Systems and Autogenous Repair of Leaks by Inert Particle Clogging

    OpenAIRE

    Richards, Colin Scott

    2016-01-01

    The formation of calcium carbonate (CaCO3) (i.e. scale) in potable water systems has long been a concern in water treatment and distribution. A literature review reveals that CaCO3 scaling issues are re-emerging due to climate change, temperature increases in hot water systems and lower use of scaling and corrosion inhibitors. Moreover, we have gathered insights that suggest CaCO3 coatings can be beneficial and stop pipeline leaks via self-repair or clogging. Ironically, the actions we are ta...

  3. An Inducible, Isogenic Cancer Cell Line System for Targeting the State of Mismatch Repair Deficiency

    Science.gov (United States)

    Bailis, Julie M.; Gordon, Marcia L.; Gurgel, Jesse L.; Komor, Alexis C.; Barton, Jacqueline K.; Kirsch, Ilan R.

    2013-01-01

    The DNA mismatch repair system (MMR) maintains genome stability through recognition and repair of single-base mismatches and small insertion-deletion loops. Inactivation of the MMR pathway causes microsatellite instability and the accumulation of genomic mutations that can cause or contribute to cancer. In fact, 10-20% of certain solid and hematologic cancers are MMR-deficient. MMR-deficient cancers do not respond to some standard of care chemotherapeutics because of presumed increased tolerance of DNA damage, highlighting the need for novel therapeutic drugs. Toward this goal, we generated isogenic cancer cell lines for direct comparison of MMR-proficient and MMR-deficient cells. We engineered NCI-H23 lung adenocarcinoma cells to contain a doxycycline-inducible shRNA designed to suppress the expression of the mismatch repair gene MLH1, and compared single cell subclones that were uninduced (MLH1-proficient) versus induced for the MLH1 shRNA (MLH1-deficient). Here we present the characterization of these MMR-inducible cell lines and validate a novel class of rhodium metalloinsertor compounds that differentially inhibit the proliferation of MMR-deficient cancer cells. PMID:24205301

  4. DNA Mismatch Repair System: Repercussions in Cellular Homeostasis and Relationship with Aging

    Directory of Open Access Journals (Sweden)

    Juan Cristóbal Conde-Pérezprina

    2012-01-01

    Full Text Available The mechanisms that concern DNA repair have been studied in the last years due to their consequences in cellular homeostasis. The diverse and damaging stimuli that affect DNA integrity, such as changes in the genetic sequence and modifications in gene expression, can disrupt the steady state of the cell and have serious repercussions to pathways that regulate apoptosis, senescence, and cancer. These altered pathways not only modify cellular and organism longevity, but quality of life (“health-span”. The DNA mismatch repair system (MMR is highly conserved between species; its role is paramount in the preservation of DNA integrity, placing it as a necessary focal point in the study of pathways that prolong lifespan, aging, and disease. Here, we review different insights concerning the malfunction or absence of the DNA-MMR and its impact on cellular homeostasis. In particular, we will focus on DNA-MMR mechanisms regulated by known repair proteins MSH2, MSH6, PMS2, and MHL1, among others.

  5. Rotator cuff repair in the Brazilian Unified Health System: Brazilian trends from 2003 to 2015

    Directory of Open Access Journals (Sweden)

    Eduardo Angeli Malavolta

    Full Text Available ABSTRACT OBJECTIVE: To assess the historical trend of rotator cuff repairs in Brazil between 2003 and 2015, using the database of the Brazilian Unified Health System's (Sistema Único de Saúde [SUS] Department of Informatics (DataSUS. METHODS: Historical series using DataSUS. Surgeries performed between 2003 and 2015 were included and data relating to cuff tear repair were assessed, including decompression procedures were included. The numerator was the total number of rotator cuff repair and the denominator, the total population of the assessed locality. Population data were based on information from the Instituto Brasileiro de Geografia e Estatística (IBGE. RESULTS: During the period, 50,207 surgeries were performed. The rate was presented as number of procedures per 100,000 inhabitants, and increased from 0.83 to 2.81, a growth of 238%. In 2015, the South region had the highest rate, 6.32, followed by the Southeast, 3.62, while the North had the lowest rate, 0.13. The growing trend can be observed in the Southeast, South, and Midwest, while the rate is stable in the North and Northeast. CONCLUSION: The rate of rotator cuff repairs in Brazil performed through the SUS increased from 0.83 to 2.81 between 2003 and 2015, representing a growth of 238%, but remains lower than that of developed countries. A trend of growth can be observed in the Southeast, South, and Midwest, while the rate is stable in the North and Northeast.

  6. Impact of DNA mismatch repair system alterations on human fertility and related treatments.

    Science.gov (United States)

    Hu, Min-hao; Liu, Shu-yuan; Wang, Ning; Wu, Yan; Jin, Fan

    2016-01-01

    DNA mismatch repair (MMR) is one of the biological pathways, which plays a critical role in DNA homeostasis, primarily by repairing base-pair mismatches and insertion/deletion loops that occur during DNA replication. MMR also takes part in other metabolic pathways and regulates cell cycle arrest. Defects in MMR are associated with genomic instability, predisposition to certain types of cancers and resistance to certain therapeutic drugs. Moreover, genetic and epigenetic alterations in the MMR system demonstrate a significant relationship with human fertility and related treatments, which helps us to understand the etiology and susceptibility of human infertility. Alterations in the MMR system may also influence the health of offspring conceived by assisted reproductive technology in humans. However, further studies are needed to explore the specific mechanisms by which the MMR system may affect human infertility. This review addresses the physiological mechanisms of the MMR system and associations between alterations of the MMR system and human fertility and related treatments, and potential effects on the next generation.

  7. Ability of Bacillus subtilis protoplasts to repair irradiated bacteriophage deoxyribonucleic acid via acquired and natural enzymatic systems

    International Nuclear Information System (INIS)

    Yasbin, R.E.; Andersen, B.J.; Sutherland, B.M.

    1981-01-01

    A novel form of enzyme therapy was achieved by utilizing protoplasts of Bacillus subtilis. Photoreactivating enzyme of Escherichia coli was successfully inserted into the protoplasts of B. subtilis treated with polyethylene glycol. This enzyme was used to photoreactivate ultraviolet-damaged bacteriophage deoxyribonucleic acid (DNA). Furthermore, in polyethylene glycol-treated protoplasts, ultraviolet-irradiated transfecting bacteriophage DNA was shown to be a functional substrate for the host DNA excision repair system. Previous results (R.E. Yasbin, J.D. Fernwalt, and P.I. Fields, J. Bacteriol.; 137: 391-396) showed that ultraviolet-irradiated bacteriophage DNA could not be repaired via the excision repair system of competent cells. Therefore, the processing of bacteriophage DNA by protoplasts and by competent cells must be different. This sensitive protoplast assay can be used to identify and to isolate various types of DNA repair enzymes

  8. Reliability modelling of repairable systems using Petri nets and fuzzy Lambda-Tau methodology

    International Nuclear Information System (INIS)

    Knezevic, J.; Odoom, E.R.

    2001-01-01

    A methodology is developed which uses Petri nets instead of the fault tree methodology and solves for reliability indices utilising fuzzy Lambda-Tau method. Fuzzy set theory is used for representing the failure rate and repair time instead of the classical (crisp) set theory because fuzzy numbers allow expert opinions, linguistic variables, operating conditions, uncertainty and imprecision in reliability information to be incorporated into the system model. Petri nets are used because unlike the fault tree methodology, the use of Petri nets allows efficient simultaneous generation of minimal cut and path sets

  9. Involvement of the DNA mismatch repair system in cisplatin sensitivity of testicular germ cell tumours

    DEFF Research Database (Denmark)

    Rudolph, Christiane; Melau, Cecilie; Nielsen, John E.

    2017-01-01

    in the majority of tumours, although the underlying mechanism largely remains to be elucidated. The aim of this study was to investigate the role of the DNA mismatch repair (MMR) system in the cisplatin sensitivity of TGCT. MethodsThe expression pattern of key MMR proteins, including MSH2, MSH6, MLH1 and PMS2...... proteins, in particular MSH2 and MLH1, which are involved in the recognition of cisplatin adducts and in activation of the DNA damage response pathway to initiate apoptosis....

  10. DNA apoptosis and stability in B-cell chronic lymphoid leukaemia: implication of the DNA double-strand breaks repair system by non homologous recombination

    International Nuclear Information System (INIS)

    Deriano, L.

    2005-01-01

    After an introduction presenting the diagnosis and treatment of chronic lymphoid leukaemia, its molecular and genetic characteristics, and its cellular origin and clonal evolution, this research thesis describes the apoptosis (definition and characteristics, cancer and chemotherapy, apoptotic ways induced by gamma irradiation), the genotoxic stresses, the different repair mechanisms for different damages, and the DNA repair processes. It reports how human chronic lymphocytic leukaemia B cells can escape DNA damage-induced apoptosis through the non-homologous end-joining DNA repair pathway, and presents non-homologous end-joining DNA repair as a potent mutagenic process in human chronic lymphocytic leukaemia B cells

  11. Bond strength of the porcelain repair system to all-ceramic copings and porcelain.

    Science.gov (United States)

    Lee, Sang J; Cheong, Chan Wook; Wright, Robert F; Chang, Brian M

    2014-02-01

    The purpose of this study was to investigate the shear bond strength of the porcelain repair system on alumina and zirconia core ceramics, comparing this strength with that of veneering porcelain. Veneering ceramic (n = 12), alumina core (n = 24), and zirconia core (n = 24) blocks measuring 10 × 5 × 5 mm(3) were fabricated. Veneering ceramic blocks were used as the control. Alumina and zirconia core blocks were divided into 2 groups (n = 12 each), and a slot (2 × 2 × 4 mm(3)) filled with veneering ceramics was prepared into one of the alumina and zirconia core groups (n = 12). Followed by surface treatments of micro-abrasion with 30 μm alumina particles, etching with 35% phosphoric acid and silane primer and bond, composite resin blocks (2 × 2 × 2 mm(3)) were built up and light polymerized onto the treated surfaces by 3 configurations: (a) composite blocks bonded onto veneering ceramic surface alone, (b) composite blocks bonded onto alumina core or zirconia core surfaces, (c) a 50% surface area of the composite blocks bonded to veneering ceramics and the other 50% surface area of the composite blocks to alumina core or zirconia core surfaces. The shear bond strength of the composite to each specimen was tested by a universal testing machine at a 0.5 mm/min crosshead speed. The shear bond strength was analyzed by unpaired t-tests for within the configuration groups and ANOVA for among the different configuration groups. When the mean shear bond strength was compared within groups of the same configuration, there were no statistically significant differences. Comparison of the shear bond strength among groups of different configurations revealed statistically significant differences. The mean shear bond strength of composite onto 100% veneering ceramic surface and composite onto 50% veneering 50% all-ceramic cores was statistically higher than that of composite onto 100% all-ceramic cores; however, the differences of the shear bond strength of composite bonded

  12. Repair mechanisms inducible to the DNA in I.M.M.S. biological systems

    International Nuclear Information System (INIS)

    Guzman, J.; Arceo, C.; Cortinas, C.; Rosa, M.E. De la; Olvera, O.; Cruces, M.; Pimentel, E.

    1990-03-01

    Given the characteristics of the MMS and the relative antecedents to the repair mechanisms in eucariontes are sought to determine the effect of the MMS on the genetic material and their repair in Drosophila melanogaster. (Author)

  13. [The quality of patient care under the German DRG system using as example the inguinal hernia repair].

    Science.gov (United States)

    Rudroff, C; Schweins, M; Heiss, M M

    2008-02-01

    The DRG system in Germany was introduced to improve and at the same time simplify the reimbursement of costs in German hospitals. Cost effectiveness and economic efficiency were the declared goals. Structural changes and increased competition among different hospitals were the consequences. The effect on the qualitiy of patient care has been discussed with some concern. Furthermore, doubts have been expressed about the correct representation of the various diagnoses and treatments in the coding system and the financial revenue. Inguinal hernia repair serves as an example to illustrate some common problems with the reimbursement in the DRG system. Virtual patients were grouped using a "Web Grouper" and analysed using the cost accounting from the G-DRG-Browser of the InEK. Additionally, the reimbursement for ambulant hernia repair was estimated. The DRG coding did not differentiate the various operative procedures for inguinal hernia repair. They all generated the same revenues. For example, the increased costs for bilateral inguinal hernia repair are not represented in the payment. Furthermore, no difference is made between primary and recurrent inguinal hernia. In the case of a short-term hospital stay, part of the revenue is retained. In the case of ambulatory treatment of inguinal hernia, the reimbursement is by far not a real compensation for the actual costs. The ideal patient in the DRG system suffers from a primary inguinal hernia, undergoes an open hernia repair without mesh, and remains for 2-3 days in hospital. Minimally invasive procedures, repair of bilateral inguinal hernia and ambulant operation are by far less profitable--if at all. The current revenues for inguinal hernia repair require improvement and adjustment to reality in order to accomplish the goals which the DRG system in Germany aims at.

  14. Radiobiological significance of DNA repair

    International Nuclear Information System (INIS)

    Kuzin, A.M.

    1978-01-01

    A short outline is given on the history of the problem relating to the repair of radiation injuries, specifically its molecular mechanisms. The most urgent problems which currently confront the researchers are noted. This is a further study on the role of DNA repair in post-radiation recovery, search for ways to activate and suppress DNA repair, investigations into the activity balance of various repair enzymes as well as the problem of errors in the structure of repairing DNA. An important role is attached to the investigations of DNA repair in solving a number of practical problems

  15. A systems-based investigation into vitamin D and skeletal muscle repair, regeneration, and hypertrophy.

    Science.gov (United States)

    Owens, Daniel J; Sharples, Adam P; Polydorou, Ioanna; Alwan, Nura; Donovan, Timothy; Tang, Jonathan; Fraser, William D; Cooper, Robert G; Morton, James P; Stewart, Claire; Close, Graeme L

    2015-12-15

    Skeletal muscle is a direct target for vitamin D. Observational studies suggest that low 25[OH]D correlates with functional recovery of skeletal muscle following eccentric contractions in humans and crush injury in rats. However, a definitive association is yet to be established. To address this gap in knowledge in relation to damage repair, a randomised, placebo-controlled trial was performed in 20 males with insufficient concentrations of serum 25(OH)D (45 ± 25 nmol/l). Prior to and following 6 wk of supplemental vitamin D3 (4,000 IU/day) or placebo (50 mg of cellulose), participants performed 20 × 10 damaging eccentric contractions of the knee extensors, with peak torque measured over the following 7 days of recovery. Parallel experimentation using isolated human skeletal muscle-derived myoblast cells from biopsies of 14 males with low serum 25(OH)D (37 ± 11 nmol/l) were subjected to mechanical wound injury, which enabled corresponding in vitro studies of muscle repair, regeneration, and hypertrophy in the presence and absence of 10 or 100 nmol 1α,25(OH)2D3. Supplemental vitamin D3 increased serum 25(OH)D and improved recovery of peak torque at 48 h and 7 days postexercise. In vitro, 10 nmol 1α,25(OH)2D3 improved muscle cell migration dynamics and resulted in improved myotube fusion/differentiation at the biochemical, morphological, and molecular level together with increased myotube hypertrophy at 7 and 10 days postdamage. Together, these preliminary data are the first to characterize a role for vitamin D in human skeletal muscle regeneration and suggest that maintaining serum 25(OH)D may be beneficial for enhancing reparative processes and potentially for facilitating subsequent hypertrophy. Copyright © 2015 the American Physiological Society.

  16. Computer modeling of properties of complex molecular systems

    Energy Technology Data Exchange (ETDEWEB)

    Kulkova, E.Yu. [Moscow State University of Technology “STANKIN”, Vadkovsky per., 1, Moscow 101472 (Russian Federation); Khrenova, M.G.; Polyakov, I.V. [Lomonosov Moscow State University, Chemistry Department, Leninskie Gory 1/3, Moscow 119991 (Russian Federation); Nemukhin, A.V. [Lomonosov Moscow State University, Chemistry Department, Leninskie Gory 1/3, Moscow 119991 (Russian Federation); N.M. Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, Kosygina 4, Moscow 119334 (Russian Federation)

    2015-03-10

    Large molecular aggregates present important examples of strongly nonhomogeneous systems. We apply combined quantum mechanics / molecular mechanics approaches that assume treatment of a part of the system by quantum-based methods and the rest of the system with conventional force fields. Herein we illustrate these computational approaches by two different examples: (1) large-scale molecular systems mimicking natural photosynthetic centers, and (2) components of prospective solar cells containing titan dioxide and organic dye molecules. We demonstrate that modern computational tools are capable to predict structures and spectra of such complex molecular aggregates.

  17. A Mobile Robotic System for the Inspection and Repair of SG Tubes in NPPs

    Directory of Open Access Journals (Sweden)

    Yong-Chil Seo

    2016-04-01

    Full Text Available The reliability and performance of a steam generator (SG is one of the serious concerns in the operation of pressurized water nuclear power plants. Because of high levels of radiation, robotic systems have been used to inspect and repair SG tubes. In this paper, we present a mobile robotic system that positions the inspection and repair tools while hanging down from the tube sheets where the tubes are fixed. All of the driving mechanisms of the mobile robot are actuated by electric motors to start its works, providing that the electric power is prepared without the additional need for an on-site air services. A special tube-holding mechanism with a high holding force has been developed to prevent falling from the tube sheets, even in the case of an electric power failure. We have also developed a quick installation guide device that guides the mobile robot to desired initial positions in the tube sheet exactly and quickly, which helps to reduce the radiation exposure of human workers during the installation work. This paper also provides on-site experimental results and lessons learned.

  18. The Molecular Basis of Double-Strand DNA Break Repair: The Critical Structure of the RAD52/RPA Complex

    National Research Council Canada - National Science Library

    Jackson, Dobra

    2001-01-01

    .... RAD52 has specific interactions with RAD51, RPA and DNA (1,2,3). The binding of RAD52 to ends of double-strand breaks has been found to be a key initiation step to DNA repair by homologous recombination...

  19. An assessment of composite repair system in offshore platform for corroded circumferential welds in super duplex steel pipe

    Directory of Open Access Journals (Sweden)

    Silvio de Barros

    2018-04-01

    Full Text Available The main aim of this study is to assess the effectiveness of a composite repair system in severely corroded circumferential welds in super duplex stainless steel pipes as a preventive measure against the premature corrosion damage at the welds. Artificial defects were fabricated on the super duplex steel tube in order to reproduce the localized corrosion damage defects found in real welded joints. Three kinds of through thickness defects were considered: 25%, 50% and 96% of the perimeter of the pipe. The performance of the repaired pipe was assessed by hydrostatic tests as per ISO 24817 standard. The results showed that the composite repair system can sustain the designed failure pressure even for the pipe damaged with through-wall defect up to 96% of the perimeter of the pipe. Hence, the composite repair system can be used as a preliminary tool to protect the unexpected or premature failure at the welds and maintain an adequate level of mechanical strength for a given operating pressure. This composite repair system can assure that the pipe will not leak until a planned maintenance of the line. Nevertheless, further work is still desirable to improve the confidence in the long-term performance of bonded composite

  20. Atucha I nuclear power plant: repair works in QK02W01 moderator system heat exchanger

    International Nuclear Information System (INIS)

    Olivieri, Luis E.; Zanni, Pablo A.

    2000-01-01

    Atucha I nuclear power plant moderator system operates with highly radioactive heavy water, a pressure of 115 Bar and temperatures of about 200 C degrees. In March 2000, an increasing leakage of heavy water to the conventional thermal circuit was detected, conducting the plant to a shut down. The development of a number of actions and measures were taken, in order to plug this leakage. The leakage was found in a heat exchanger, which is located in a place of difficult access, with a high radiological yield and which, according to design, it was not considered to be mechanically repaired. It is a U bend tubes heat exchanger, weighting about 20 tons, and with a heavy water flow of 800 tons/h on the primary circuit, and 950 tons/h of ordinary water on the secondary side. Foreseeing this event, it had been designed and constructed special equipment and procedures, by means of a contract, with the Company INVAP SA. Repair works were carried out within a period of eighty-six (86) days, from which, forty five days were used to repair the component itself. A considerable amount of time was used to prepare simulators and the training of personnel. Due to the high radiological yield and the strict care of radiological standards, it was necessary the participation of 300 persons, integrating a collective dose of 4,86 Sv-m. It was necessary the construction of platforms and auxiliary stairs so as to make the work place accessible, as well as lifting and movement devices for heavy components, since this area does not have such kind of facilities. Welding and cutting machines remote controlled as well as manipulators which operated in front of the exchanger tube sheet were used. The aim was the reduction of dose values as much as possible. Special shielding were developed and in some cases it was necessary the adoption of drastic measures such as the cutting of bolts or pipes. The failure was detected and the tube was plugged. Also were plugged those tubes with wall thickness

  1. Karolinska institutet 200-year anniversary. Symposium on traumatic injuries in the nervous system: injuries to the spinal cord and peripheral nervous system - injuries and repair, pain problems, lesions to brachial plexus.

    Science.gov (United States)

    Sköld, Mattias K; Svensson, Mikael; Tsao, Jack; Hultgren, Thomas; Landegren, Thomas; Carlstedt, Thomas; Cullheim, Staffan

    2011-01-01

    The Karolinska Institutet 200-year anniversary symposium on injuries to the spinal cord and peripheral nervous system gathered expertise in the spinal cord, spinal nerve, and peripheral nerve injury field spanning from molecular prerequisites for nerve regeneration to clinical methods in nerve repair and rehabilitation. The topics presented at the meeting covered findings on adult neural stem cells that when transplanted to the hypoglossal nucleus in the rat could integrate with its host and promote neuron survival. Studies on vascularization after intraspinal replantation of ventral nerve roots and microarray studies in ventral root replantation as a tool for mapping of biological patterns typical for neuronal regeneration were discussed. Different immune molecules in neurons and glia and their very specific roles in synapse plasticity after injury were presented. Novel strategies in repair of injured peripheral nerves with ethyl-cyanoacrylate adhesive showed functional recovery comparable to that of conventional epineural sutures. Various aspects on surgical techniques which are available to improve function of the limb, once the nerve regeneration after brachial plexus lesions and repair has reached its limit were presented. Moreover, neurogenic pain after amputation and its treatment with mirror therapy were shown to be followed by dramatic decrease in phantom limb pain. Finally clinical experiences on surgical techniques to repair avulsed spinal nerve root and the motoric as well as sensoric regain of function were presented.

  2. Karolinska Institutet 200-Year Anniversary. Symposium on Traumatic Injuries in the Nervous System: Injuries to the Spinal Cord and Peripheral Nervous System – Injuries and Repair, Pain Problems, Lesions to Brachial Plexus

    Science.gov (United States)

    Sköld, Mattias K.; Svensson, Mikael; Tsao, Jack; Hultgren, Thomas; Landegren, Thomas; Carlstedt, Thomas; Cullheim, Staffan

    2011-01-01

    The Karolinska Institutet 200-year anniversary symposium on injuries to the spinal cord and peripheral nervous system gathered expertise in the spinal cord, spinal nerve, and peripheral nerve injury field spanning from molecular prerequisites for nerve regeneration to clinical methods in nerve repair and rehabilitation. The topics presented at the meeting covered findings on adult neural stem cells that when transplanted to the hypoglossal nucleus in the rat could integrate with its host and promote neuron survival. Studies on vascularization after intraspinal replantation of ventral nerve roots and microarray studies in ventral root replantation as a tool for mapping of biological patterns typical for neuronal regeneration were discussed. Different immune molecules in neurons and glia and their very specific roles in synapse plasticity after injury were presented. Novel strategies in repair of injured peripheral nerves with ethyl-cyanoacrylate adhesive showed functional recovery comparable to that of conventional epineural sutures. Various aspects on surgical techniques which are available to improve function of the limb, once the nerve regeneration after brachial plexus lesions and repair has reached its limit were presented. Moreover, neurogenic pain after amputation and its treatment with mirror therapy were shown to be followed by dramatic decrease in phantom limb pain. Finally clinical experiences on surgical techniques to repair avulsed spinal nerve root and the motoric as well as sensoric regain of function were presented. PMID:21629875

  3. Molecular communications and nanonetworks from nature to practical systems

    CERN Document Server

    Atakan, Barış

    2014-01-01

    In this book, the concepts of molecular communications and nanonetworks are introduced. Throughout the book, the existing molecular communication paradigms are categorized into two main groups. The first group includes the Passive Molecular Communication (PMC) paradigms in which molecules freely diffuse to transfer information from a transmitter to a receiver. The second group includes the Active Molecular Communication (AMC) paradigms in which molecules are carried or guided by some mediators such as molecular motors, gap junction channels and bacteria. In the book, after briefly discussing why molecular communication is needed for the sophisticated nano and biotechnology applications, the existing molecular communication systems are first presented. Then, the principles of diffusion phenomena and molecular reception with absorbers and the ligand-receptor binding mechanism are introduced. Based on these principles, the communication theories and techniques are given for the PMC. Then, the physical dynamics o...

  4. A method for the calculation of the cumulative failure probability distribution of complex repairable systems

    International Nuclear Information System (INIS)

    Caldarola, L.

    1976-01-01

    A method is proposed for the analytical evaluation of the cumulative failure probability distribution of complex repairable systems. The method is based on a set of integral equations each one referring to a specific minimal cut set of the system. Each integral equation links the unavailability of a minimal cut set to its failure probability density distribution and to the probability that the minimal cut set is down at the time t under the condition that it was down at time t'(t'<=t). The limitations for the applicability of the method are also discussed. It has been concluded that the method is applicable if the process describing the failure of a minimal cut set is a 'delayed semi-regenerative process'. (Auth.)

  5. A real-time expert system for self-repairing flight control

    Science.gov (United States)

    Gaither, S. A.; Agarwal, A. K.; Shah, S. C.; Duke, E. L.

    1989-01-01

    An integrated environment for specifying, prototyping, and implementing a self-repairing flight-control (SRFC) strategy is described. At an interactive workstation, the user can select paradigms such as rule-based expert systems, state-transition diagrams, and signal-flow graphs and hierarchically nest them, assign timing and priority attributes, establish blackboard-type communication, and specify concurrent execution on single or multiple processors. High-fidelity nonlinear simulations of aircraft and SRFC systems can be performed off-line, with the possibility of changing SRFC rules, inference strategies, and other heuristics to correct for control deficiencies. Finally, the off-line-generated SRFC can be transformed into highly optimized application-specific real-time C-language code. An application of this environment to the design of aircraft fault detection, isolation, and accommodation algorithms is presented in detail.

  6. Evolution and Adaptation in Pseudomonas aeruginosa Biofilms Driven by Mismatch Repair System-Deficient Mutators

    DEFF Research Database (Denmark)

    Luján, Adela M.; Maciá, María D.; Yang, Liang

    2011-01-01

    , which are rarely eradicated despite intensive antibiotic therapy. Current knowledge indicates that three major adaptive strategies, biofilm development, phenotypic diversification, and mutator phenotypes [driven by a defective mismatch repair system (MRS)], play important roles in P. aeruginosa chronic...... infections, but the relationship between these strategies is still poorly understood. We have used the flow-cell biofilm model system to investigate the impact of the mutS associated mutator phenotype on development, dynamics, diversification and adaptation of P. aeruginosa biofilms. Through competition...... diversification, evidenced by biofilm architecture features and by a wider range and proportion of morphotypic colony variants, respectively. Additionally, morphotypic variants generated in mutator biofilms showed increased competitiveness, providing further evidence for mutator-driven adaptive evolution...

  7. Building an adaptive agent to monitor and repair the electrical power system of an orbital satellite

    Science.gov (United States)

    Tecuci, Gheorghe; Hieb, Michael R.; Dybala, Tomasz

    1995-01-01

    Over several years we have developed a multistrategy apprenticeship learning methodology for building knowledge-based systems. Recently we have developed and applied our methodology to building intelligent agents. This methodology allows a subject matter expert to build an agent in the same way in which the expert would teach a human apprentice. The expert will give the agent specific examples of problems and solutions, explanations of these solutions, or supervise the agent as it solves new problems. During such interactions, the agent learns general rules and concepts, continuously extending and improving its knowledge base. In this paper we present initial results on applying this methodology to build an intelligent adaptive agent for monitoring and repair of the electrical power system of an orbital satellite, stressing the interaction with the expert during apprenticeship learning.

  8. Sensitivity analysis of repairable redundant system with switching failure and geometric reneging

    Directory of Open Access Journals (Sweden)

    Chandra Shekhar

    2017-09-01

    Full Text Available This study deals with the performance modeling and reliability analysis of a redundant machining system composed of several functional machines. To analyze the more realistic scenarios, the concepts of switching failure and geometric reneging are included. The time-to-breakdown and repair time of operating and standby machines are assumed to follow the exponential distribution. For the quantitative assessment of the machine interference problem, various performance measures such as mean-time-to-failure, reliability, reneging rate, etc. have been formulated. To show the practicability of the developed model, a numerical illustration has been presented. For the practical justification and validity of the results established, the sensitivity analysis of reliability indices has been presented by varying different system descriptors.

  9. Lethal effects of solar radiation in proficient and deficient bacteria in repair systems

    International Nuclear Information System (INIS)

    Sousa Neto, A. de.

    1980-01-01

    A study of the lethal action of solar radiation on strains of E.coli K12, proficient or deficient in repair systems, as well as the wild type strain gene products are involved in repair of damage induced by solar radiation. The inactivation of the various bacterial strains (normalized to a dose equivalent to radiation at a wavelength 254 nm) suggests that the more energetic wavelengths of the solar spectrum (290-320 nm) could be responsible for the primary damage that occurs in the DNA. The reduction in the shoulder of the survival curve in wild type strains in indicative of induction of sub-lethal damage in this region of the curve. Analysing solar inactivation curves of the bacterial strains (normalised by spore dosimetry) together with those of the same strains irradiated with UV at 254 nm, it was evident that 254 nm is not the ideal wavelength for comparison. This analysis also indicated that in addition to damage to DNA, other factors are involved in the solar radiation inactivation of wild type strains. (author)

  10. Space Transportation System (STS)-117 External Tank (ET)-124 Hail Damage Repair Assessment

    Science.gov (United States)

    Wilson, Timmy R.; Gentz, Steven J.; Barth, Timothy S.; Minute, Stephen A.; Flowers, Cody P.; Hamilton, David A.; Null, Cynthia H.; Schafer, Charles F.

    2009-01-01

    Severe thunderstorms with associated hail and high winds struck the STS-117 stack on February 26, 2007. Peak winds were recorded at 62 knots with hail sizes ranging from 0.3 inch to 0.8 inch in diameter. As a result of the storm, the North Carolina Foam Institute (NCFI) type 24-124 Thermal Protection System (TPS) foam on the liquid oxygen (LO2) ogive acreage incurred significant impact damage. The NCFI on the ET intertank and the liquid hydrogen (LH2) acreage sustained hail damage. The Polymer Development Laboratory (PDL)-1034 foam of the LO2 ice frost ramps (IFRs) and the Super-Lightweight Ablator (SLA) of the LO2 cable tray also suffered minor damage. NASA Engineering and Safety Center (NESC) was asked to assess the technical feasibility of repairing the ET TPS, the reasonableness of conducting those repairs with the vehicle in a vertical, integrated configuration at the Kennedy Space Center (KSC) Vehicle Assemble Building (VAB), and to address attendant human factors considerations including worker fatigue and the potential for error. The outcome of the assessment is recorded in this document.

  11. Availability of K-out-of-N:G systems with non-identical components subject to repair priorities

    International Nuclear Information System (INIS)

    Khatab, A.; Nahas, N.; Nourelfath, M.

    2009-01-01

    In this paper, a K-out-of-N:G system with N categories of components is studied. Each component category is characterized by its own failure and repair rates. There are R repair facilities, and repair priorities are specified between the N non-identical components. An algorithm for automatic construction of the system state transition diagram is presented. The stationary availability of each component and that of the system are evaluated by using a multi-dimensional Markov model. We show how this model can be represented as a network of stochastic automata with state-dependent transitions that can be implemented via generalized tensor (or Kronecker) algebra. For the efficiency assessment, an analog Monte Carlo simulation model is developed. Experiments are then conducted and simulation results are compared to those obtained by the proposed approach

  12. Dynamic reliability assessment and prediction for repairable systems with interval-censored data

    International Nuclear Information System (INIS)

    Peng, Yizhen; Wang, Yu; Zi, YanYang; Tsui, Kwok-Leung; Zhang, Chuhua

    2017-01-01

    The ‘Test, Analyze and Fix’ process is widely applied to improve the reliability of a repairable system. In this process, dynamic reliability assessment for the system has been paid a great deal of attention. Due to instrument malfunctions, staff omissions and imperfect inspection strategies, field reliability data are often subject to interval censoring, making dynamic reliability assessment become a difficult task. Most traditional methods assume this kind of data as multiple normal distributed variables or the missing mechanism as missing at random, which may cause a large bias in parameter estimation. This paper proposes a novel method to evaluate and predict the dynamic reliability of a repairable system subject to interval-censored problem. First, a multiple imputation strategy based on the assumption that the reliability growth trend follows a nonhomogeneous Poisson process is developed to derive the distributions of missing data. Second, a new order statistic model that can transfer the dependent variables into independent variables is developed to simplify the imputation procedure. The unknown parameters of the model are iteratively inferred by the Monte Carlo expectation maximization (MCEM) algorithm. Finally, to verify the effectiveness of the proposed method, a simulation and a real case study for gas pipeline compressor system are implemented. - Highlights: • A new multiple imputation strategy was developed to derive the PDF of missing data. • A new order statistic model was developed to simplify the imputation procedure. • The parameters of the order statistic model were iteratively inferred by MCEM. • A real cases study was conducted to verify the effectiveness of the proposed method.

  13. Development of a rocking R/C shear wall system implementing repairable structural fuses

    Science.gov (United States)

    Parsafar, Saeed; Moghadam, Abdolreza S.

    2017-09-01

    In the last decades, the concept of earthquake resilient structural systems is becoming popular in which the rocking structure is considered as a viable option for buildings in regions of high seismicity. To this end, a novel wall-base connection based on the " repairable structure" approach is proposed and evaluated. The proposed system is made of several steel plates and high strength bolts act as a friction connection. To achieve the desired rocking motion in the proposed system, short-slotted holes are used in vertical directions for connecting the steel plates to the shear wall (SW). The experimental and numerical studies were performed using a series of displacement control quasi-static cyclic tests on a reference model and four different configurations of the proposed connection installed at the wall corners. The seismic response of the proposed system is compared to the conventional SW in terms of energy dissipation and damage accumulation. In terms of energy dissipation, the proposed system depicted better performance with 95% more energy dissipation capability compared to conventional SW. In terms of damage accumulation, the proposed SW system is nearly undamaged compared to the conventional wall system, which was severely damaged at the wall-base region. Overall, the introduced concept presents a feasible solution for R/C structures when a low-damage design is targeted, which can improve the seismic performance of the structural system significantly.

  14. Joint optimisation of spare part inventory, maintenance frequency and repair capacity for k-out-of-N systems

    NARCIS (Netherlands)

    de Smidt-Destombes, Karin S.; van der Heijden, Matthijs C.; van Harten, Aart

    2009-01-01

    To achieve a high system availability at minimal costs, relevant decisions include the choice of preventive maintenance frequency, spare part inventory levels and spare part repair capacity. We develop heuristics for the joint optimisation of these variables for (a) a single k-out-of-N system under

  15. Development of the Fragment Molecular Orbital Method for Calculating Nonlocal Excitations in Large Molecular Systems.

    Science.gov (United States)

    Fujita, Takatoshi; Mochizuki, Yuji

    2018-04-19

    We developed the fragment-based method for calculating nonlocal excitations in large molecular systems. This method is based on the multilayer fragment molecular orbital method and the configuration interaction single (CIS) wave function using localized molecular orbitals. The excited-state wave function for the whole system is described as a superposition of configuration state functions (CSFs) for intrafragment excitations and for interfragment charge-transfer excitations. The formulation and calculations of singlet excited-state Hamiltonian matrix elements in the fragment CSFs are presented in detail. The efficient approximation schemes for calculating the matrix elements are also presented. The computational efficiency and the accuracy were evaluated using the molecular dimers and molecular aggregates. We confirmed that absolute errors of 50 meV (relative to the conventional calculations) are achievable for the molecular systems in their equilibrium geometries. The perturbative electron correlation correction to the CIS excitation energies is also demonstrated. The present theory can compute a large number of excited states in large molecular systems; in addition, it allows for the systematic derivation of a model exciton Hamiltonian. These features are useful for studying excited-state dynamics in condensed molecular systems based on the ab initio electronic structure theory.

  16. Left cardiac chambers reverse remodeling after percutaneous mitral valve repair with the MitraClip system.

    Science.gov (United States)

    Scandura, Salvatore; Ussia, Gian Paolo; Capranzano, Piera; Caggegi, Anna; Sarkar, Kunal; Cammalleri, Valeria; Mangiafico, Sarah; Chiarandà, Marta; Immè, Sebastiano; Di Pasqua, Fabio; Pistritto, Anna Maria; Millan, Giovanni; Tamburino, Corrado

    2012-10-01

    Successful mitral valve surgical repair, decreasing volume overload, has been shown to provide reverse left ventricular (LV) and/or left atrial remodeling in most patients. Percutaneous mitral valve repair with the MitraClip system (Abbott, Abbott Park, IL) has been associated with favorable clinical outcomes in patients with mitral regurgitation at high risk of surgery. However, specific data on left cardiac chambers reverse remodeling after such procedures are limited. This was a prospective observational study of consecutive patients at high risk of surgery, with moderate-to-severe or severe mitral regurgitation undergoing MitraClip system implantation. Follow-up echocardiography was performed at 6 months. The evaluated parameters were the LV end-diastolic and end-systolic volume indexes, LV sphericity index, LV ejection fraction, and left atrial volume index. Reverse LV remodeling was defined as a decrease of 10% in the LV end-diastolic volume index. The study population included 44 patients: 14 with degenerative and 30 with functional mitral regurgitation. At 6 months of follow-up, significant reductions in the median and interquartile range of the sphericity index (from 0.57 [interquartile range 0.54-0.62] to 0.54 [interquartile range 0.50-0.58]; P interquartile range 63.0-102.2] to 60.7 mL/m(2) [50.8-84.4]; P interquartile range 28.2-70.5] to 28.9 mL/m(2) [interquartile range 22.2-55.8]; P interquartile range 30.0-55.0%] to 46.0% [interquartile range 35.0-58.0%]; P < .001) from baseline to 6 months. Minor differences in the left atrial volume index were observed. Reverse remodeling, according to the specified definition, was observed in 77.3% of the patients. The present study reports positive LV reshape effects after mitral valve repair with the MitraClip system, showing significant improvements in LV size and function. Copyright © 2012 American Society of Echocardiography. Published by Mosby, Inc. All rights reserved.

  17. Agent-Based Modeling in Molecular Systems Biology.

    Science.gov (United States)

    Soheilypour, Mohammad; Mofrad, Mohammad R K

    2018-06-08

    Molecular systems orchestrating the biology of the cell typically involve a complex web of interactions among various components and span a vast range of spatial and temporal scales. Computational methods have advanced our understanding of the behavior of molecular systems by enabling us to test assumptions and hypotheses, explore the effect of different parameters on the outcome, and eventually guide experiments. While several different mathematical and computational methods are developed to study molecular systems at different spatiotemporal scales, there is still a need for methods that bridge the gap between spatially-detailed and computationally-efficient approaches. In this review, we summarize the capabilities of agent-based modeling (ABM) as an emerging molecular systems biology technique that provides researchers with a new tool in exploring the dynamics of molecular systems/pathways in health and disease. © 2018 WILEY Periodicals, Inc.

  18. Identification of DNA polymerase molecules repairing DNA irradiated damage and molecular biological study on modified factors of mutation rate

    Energy Technology Data Exchange (ETDEWEB)

    Yamada, Koichi; Inoue, Shuji [National Inst. of Healthand Nutrition, Tokyo (Japan)

    1999-02-01

    DNA repairing polymerase has not been identified in human culture cells because the specificities of enzyme inhibitors used in previous studies were not so high. In this study, anti-sense oligonucleotides were transfected into human fibroblast cells by electroporation and several clones selected by geneticin treatment were found to express the RNA of the incorporated DNA. However, the expression was not significant and its reproducibility was poor. Then, a study on repairing mechanism was made using XP30 RO and XP 115 LO cells which are variant cells of xeroderma pigmentosum, a human hereditary disease aiming to identify the DNA polymerase related to the disease. There were abnormalities in DNA polymerase subunit {delta} or {epsilon} which consists DNA replication complex. Thus, it was suggested that the DNA replication of these mutant cells might terminate at the site containing such abnormality. (M.N.)

  19. Remote Laser Evaporative Molecular Absorption Spectroscopy Sensor System

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose a sensor system capable of remotely probing the molecular composition of cold solar system targets (asteroids, comets, planets, moons), such as from a...

  20. Failure mechanism dependence and reliability evaluation of non-repairable system

    International Nuclear Information System (INIS)

    Chen, Ying; Yang, Liu; Ye, Cui; Kang, Rui

    2015-01-01

    Reliability study of electronic system with the physics-of-failure method has been promoted due to the increase knowledge of electronic failure mechanisms. System failure initiates from independent failure mechanisms, have effect on or affect by other failure mechanisms and finally result in system failure. Failure mechanisms in a non-repairable system have many kinds of correlation. One failure mechanism developing to a certain degree will trigger, accelerate or inhibit another or many other failure mechanisms, some kind of failure mechanisms may have the same effect on the failure site, component or system. The destructive effect will be accumulated and result in early failure. This paper presents a reliability evaluation method considering correlativity among failure mechanisms, which includes trigger, acceleration, inhibition, accumulation, and competition. Based on fundamental rule of physics of failure, decoupling methods of these correlations are discussed. With a case, reliability of electronic system is evaluated considering failure mechanism dependence. - Highlights: • Five types of failure mechanism correlations are described. • Decoupling methods of these correlations are discussed. • A reliability evaluation method considering mechanism dependence is proposed. • Results are quite different to results under failure independence assumption

  1. Reliability Analysis of a Cold Standby System with Imperfect Repair and under Poisson Shocks

    Directory of Open Access Journals (Sweden)

    Yutian Chen

    2014-01-01

    Full Text Available This paper considers the reliability analysis of a two-component cold standby system with a repairman who may have vacation. The system may fail due to intrinsic factors like aging or deteriorating, or external factors such as Poisson shocks. The arrival time of the shocks follows a Poisson process with the intensity λ>0. Whenever the magnitude of a shock is larger than the prespecified threshold of the operating component, the operating component will fail. The paper assumes that the intrinsic lifetime and the repair time on the component are an extended Poisson process, the magnitude of the shock and the threshold of the operating component are nonnegative random variables, and the vacation time of the repairman obeys the general continuous probability distribution. By using the vector Markov process theory, the supplementary variable method, Laplace transform, and Tauberian theory, the paper derives a number of reliability indices: system availability, system reliability, the rate of occurrence of the system failure, and the mean time to the first failure of the system. Finally, a numerical example is given to validate the derived indices.

  2. Propagated failure analysis for non-repairable systems considering both global and selective effects

    International Nuclear Information System (INIS)

    Wang Chaonan; Xing Liudong; Levitin, Gregory

    2012-01-01

    This paper proposes an algorithm for the reliability analysis of non-repairable binary systems subject to competing failure propagation and failure isolation events with both global and selective failure effects. A propagated failure that originates from a system component causes extensive damage to the rest of the system. Global effect happens when the propagated failure causes the entire system to fail; whereas selective effect happens when the propagated failure causes only failure of a subset of system components. In both cases, the failure propagation that originates from some system components (referred to as dependent components) can be isolated because of functional dependence between the dependent components and a component that prevents the failure propagation (trigger components) when the failure of the trigger component happens before the occurrence of the propagated failure. Most existing studies focus on the analysis of propagated failures with global effect. However, in many cases, propagated failures affect only a subset of system components not the entire system. Existing approaches for analyzing propagated failures with selective effect are limited to series-parallel systems. This paper proposes a combinatorial method for the propagated failure analysis considering both global and selective effects as well as the competition with the failure isolation in the time domain. The proposed method is not limited to series-parallel systems and has no limitation on the type of time-to-failure distributions for the system components. The method is verified using the Markov-based method. An example of computer memory systems is analyzed to demonstrate the application of the proposed method.

  3. Logic circuits based on molecular spider systems.

    Science.gov (United States)

    Mo, Dandan; Lakin, Matthew R; Stefanovic, Darko

    2016-08-01

    Spatial locality brings the advantages of computation speed-up and sequence reuse to molecular computing. In particular, molecular walkers that undergo localized reactions are of interest for implementing logic computations at the nanoscale. We use molecular spider walkers to implement logic circuits. We develop an extended multi-spider model with a dynamic environment wherein signal transmission is triggered via localized reactions, and use this model to implement three basic gates (AND, OR, NOT) and a cascading mechanism. We develop an algorithm to automatically generate the layout of the circuit. We use a kinetic Monte Carlo algorithm to simulate circuit computations, and we analyze circuit complexity: our design scales linearly with formula size and has a logarithmic time complexity. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  4. The on-line repair, improvement and expansion of a working multicomputer control system for the CERN SPS accelerator

    International Nuclear Information System (INIS)

    Altaber, J.; Beck, F.; Collins, M.; Crowley-Milling, M.C.; Rausch, R.

    1979-01-01

    The 400 GeV proton synchrotron at CERN was first commissioned in 1976. Those of its features which are pertinent to the design of the control system are summarized. The paper then proceeds as follows: changes to the control system (changes to applications programs, equipment handling routines, system software changes); hardware increases and repairs; changes to the character of the system (hardware changes, microprocessors); conclusions. (U.K.)

  5. In vitro Repair of Oxidative DNA Damage by Human Nucleotide Excision Repair System: Possible Explanation for Neurodegeneration in Xeroderma Pigmentosum Patients

    Science.gov (United States)

    Reardon, Joyce T.; Bessho, Tadayoshi; Kung, Hsiang Chuan; Bolton, Philip H.; Sancar, Aziz

    1997-08-01

    Xeroderma pigmentosum (XP) patients fail to remove pyrimidine dimers caused by sunlight and, as a consequence, develop multiple cancers in areas exposed to light. The second most common sign, present in 20-30% of XP patients, is a set of neurological abnormalities caused by neuronal death in the central and peripheral nervous systems. Neural tissue is shielded from sunlight-induced DNA damage, so the cause of neurodegeneration in XP patients remains unexplained. In this study, we show that two major oxidative DNA lesions, 8-oxoguanine and thymine glycol, are excised from DNA in vitro by the same enzyme system responsible for removing pyrimidine dimers and other bulky DNA adducts. Our results suggest that XP neurological disease may be caused by defective repair of lesions that are produced in nerve cells by reactive oxygen species generated as by-products of an active oxidative metabolism.

  6. Real-Time Multifault Rush Repairing Strategy Based on Utility Theory and Multiagent System in Distribution Networks

    Directory of Open Access Journals (Sweden)

    Zhao Hao

    2016-01-01

    Full Text Available The problem of multifault rush repair in distribution networks (DNs is a multiobjective dynamic combinatorial problem with topology constraints. The problem consists of archiving an optimal faults’ allocation strategy to squads and an admissible multifault rush repairing strategy with coordinating switch operations. In this article, the utility theory is introduced to solve the first problem and a new discrete bacterial colony chemotaxis (DBCC algorithm is proposed for the second problem to determine the optimal sequence for each squad to repair faults and the corresponding switch operations. The above solution is called the two-stage approach. Additionally, a double mathematical optimization model based on the fault level is proposed in the second stage to minimize the outage loss and total repairing time. The real-time adjustment multiagent system (RA-MAS is proposed to provide facility to achieve online multifault rush repairing strategy in DNs when there are emergencies after natural disasters. The two-stage approach is illustrated with an example from a real urban distribution network and the simulation results show the effectiveness of the two-stage approach.

  7. On the interaction between maintenance, spare part inventories and repair capacity for a k-out-of-N-system with wear-out

    NARCIS (Netherlands)

    de Smidt-Destombes, Karin S.; van der Heijden, Matthijs C.; van Harten, Aart

    2006-01-01

    In this paper we consider a k-out-of-N system with identical, repairable components under a condition-based maintenance policy. Maintenance consists of replacing all failed and/or aged components. Next, the replaced components have to be repaired. The system availability can be controlled by the

  8. On the interaction between maintenance, spare part inventories and repair capacity for a k-out-of-N system with wear-out

    NARCIS (Netherlands)

    Smidt-Destombes, K.S. de; Heijden, M.C. van der; Harten, A. van

    2006-01-01

    In this paper we consider a k-out-of-N system with identical, repairable components under a condition-based maintenance policy. Maintenance consists of replacing all failed and/or aged components. Next, the replaced components have to be repaired. The system availability can be controlled by the

  9. Participatory Design Research as a Practice for Systemic Repair: Doing Hand-in-Hand Math Research with Families

    Science.gov (United States)

    Booker, Angela; Goldman, Shelley

    2016-01-01

    Success and failure in formal mathematics education has been used to legitimize stratification. We describe participatory design research as a methodology for systemic repair. The analysis describes epistemic authority--exercising the right or the power to know--as a form of agency in processes of mathematical problem solving and learning. We…

  10. Early passage bone marrow stromal cells express genes involved in nervous system development supporting their relevance for neural repair

    NARCIS (Netherlands)

    Nandoe Tewarie, R.D.S.; Bossers, K.; Ritfeld, G.J.; Blits, B.; Grotenhuis, J.A.; Verhaagen, J.; Oudega, M.

    2011-01-01

    PURPOSE: The assessment of the capacity of bone marrow stromal cells (BMSC) to repair the nervous system using gene expression profiling. The evaluation of effects of long-term culturing on the gene expression profile of BMSC. METHODS: Fourty four k whole genome rat microarrays were used to study

  11. Study of the performance of four repairing material systems for hydraulic structures of concrete dams

    Directory of Open Access Journals (Sweden)

    Kormann A. C. M.

    2003-01-01

    Full Text Available Four types of repairing materials are studied as function of either a conventional concrete or a reference-concrete (RefC, these are: polymer-modified cement mortar (PMor, steel fiber concrete (SFco, epoxy mortar (EMor and silica fume mortar (SFmo, to be applied in hydraulic structures surfaces subjected to a high velocity water flow. Besides the mechanical requests and wearing resistance of hydraulic concrete dam structures, especially the spillway surfaces, the high solar radiation, the environmental temperature and wet and dry cycles, contribute significantly to the reduction of their lifespan. RefC and the SFco were developed based on a usual concrete mixture used in slabs of spillways. The average RefC mixture used was 1: 1.61: 2.99: 0.376, with Pozzolan-modified Portland cement consumption of 425 kg/m³. EMor and PMor mixtures followed the information given by the manufacturers and lab experience. Tests on concrete samples were carried out in laboratory simulating normally found environmental situations in order to control the mechanical resistance and the aging imposed conditions, such as solar radiation and humidity. Also, physicochemical characterizing tests were made for all used materials. From the analyzed results, two of them presented a higher performance: the EMor and SFmo. SFco presented good adherence to the RefC and good mechanical performance. However, it also presented apparent metal corrosion in humidity tests, being indicated for use, with caution, as an intermediate layer in underwater repairs. In a general classification, considering all tests, including their field applications, the better performance material systems were EMor- SFmo> SFco> PMor.

  12. MULTI-AGENT APPROACH TO BUILDING AN INTELLIGENT VEHICLE MAINTENANCE AND REPAIR SYSTEM

    Directory of Open Access Journals (Sweden)

    V. Pavlenko

    2017-12-01

    Full Text Available To ensure the reliability of the car, early detection and prevention of the occurrence and development of failures is required in order to reduce the costs of maintenance and repair. Multi-agent technologies make it possible to raise the level of technical reliability of cars and minimize the costs of performing repair and maintenance operations.

  13. Advances in study of molecular imaging reporte gene systems

    International Nuclear Information System (INIS)

    Wu Tao; An Rui

    2010-01-01

    The use of molecular imaging reporter gene systems has allowed gene therapy to move from the laboratory to the clinical application, which provides methodology to monitor the expression of therapeutic gene noninvasively and achieve quantitative outcome in vivo. Recently, the radionuclide reporter gene still is the focus many studies, but MRI and optical reporter gene have gradually played a important part in reporter gene systems. On the basis of combination of multi-subject, for example applied chemistry and molecular biology, more and more new modified reporter genes and molecular probes have spread out. This paper mainly introduces the advantages and disadvantages of reporter gene system and development trends. (authors)

  14. From Molecular Classification to Targeted Therapeutics: The Changing Face of Systemic Therapy in Metastatic Gastroesophageal Cancer

    Directory of Open Access Journals (Sweden)

    Adrian Murphy

    2015-01-01

    Full Text Available Histological classification of adenocarcinoma or squamous cell carcinoma for esophageal cancer or using the Lauren classification for intestinal and diffuse type gastric cancer has limited clinical utility in the management of advanced disease. Germline mutations in E-cadherin (CDH1 or mismatch repair genes (Lynch syndrome were identified many years ago but given their rarity, the identification of these molecular alterations does not substantially impact treatment in the advanced setting. Recent molecular profiling studies of upper GI tumors have added to our knowledge of the underlying biology but have not led to an alternative classification system which can guide clinician’s therapeutic decisions. Recently the Cancer Genome Atlas Research Network has proposed four subtypes of gastric cancer dividing tumors into those positive for Epstein-Barr virus, microsatellite unstable tumors, genomically stable tumors, and tumors with chromosomal instability. Unfortunately to date, many phase III clinical trials involving molecularly targeted agents have failed to meet their survival endpoints due to their use in unselected populations. Future clinical trials should utilize molecular profiling of individual tumors in order to determine the optimal use of targeted therapies in preselected patients.

  15. A New Molecular Surveillance System for Leishmaniasis

    Science.gov (United States)

    Pandey, Kishor; Pandey, Basu Dev; Mallik, Arun Kumar; Acharya, Jyoti; Kato, Kentaro; Kaneko, Osamu; Ferreira, Pedro Eduardo

    2014-01-01

    Abstract. Presently, global efforts are being made to control and eradicate the deadliest tropical diseases through the improvement of adequate interventions. A critical point for programs to succeed is the prompt and accurate diagnosis in endemic regions. Rapid diagnostic tests (RDTs) are being massively deployed and used to improve diagnosis in tropical countries. In the present report, we evaluated the hypothesis of, after use for diagnosis, the reuse of the Leishmania RDT kit as a DNA source, which can be used downstream as a molecular surveillance and/or quality control tool. As a proof of principle, a polymerase chain reaction-based method was used to detect Leishmania spp. minicircle kinetoplast DNA from leishmaniasis RDT kits. Our results show that Leishmania spp. DNA can be extracted from used RDTs and may constitute an important, reliable, and affordable tool to assist in future leishmaniasis molecular surveillance methods. PMID:24752687

  16. Electron-nuclear dynamics of molecular systems

    International Nuclear Information System (INIS)

    Diz, A.; Oehrn, Y.

    1994-01-01

    The content of an ab initio time-dependent theory of quantum molecular dynamics of electrons and atomic nuclei is presented. Employing the time-dependent variational principle and a family of approximate state vectors yields a set of dynamical equations approximating the time-dependent Schroedinger equation. These equations govern the time evolution of the relevant state vector parameters as molecular orbital coefficients, nuclear positions, and momenta. This approach does not impose the Born-Oppenheimer approximation, does not use potential energy surfaces, and takes into account electron-nuclear coupling. Basic conservation laws are fully obeyed. The simplest model of the theory employs a single determinantal state for the electrons and classical nuclei and is implemented in the computer code ENDyne. Results from this ab-initio theory are reported for ion-atom and ion-molecule collisions

  17. DNA Damage: Quantum Mechanics/Molecular Mechanics Study on the Oxygen Binding and Substrate Hydroxylation Step in AlkB Repair Enzymes

    Science.gov (United States)

    Quesne, Matthew G; Latifi, Reza; Gonzalez-Ovalle, Luis E; Kumar, Devesh; de Visser, Sam P

    2014-01-01

    AlkB repair enzymes are important nonheme iron enzymes that catalyse the demethylation of alkylated DNA bases in humans, which is a vital reaction in the body that heals externally damaged DNA bases. Its mechanism is currently controversial and in order to resolve the catalytic mechanism of these enzymes, a quantum mechanics/molecular mechanics (QM/MM) study was performed on the demethylation of the N1-methyladenine fragment by AlkB repair enzymes. Firstly, the initial modelling identified the oxygen binding site of the enzyme. Secondly, the oxygen activation mechanism was investigated and a novel pathway was found, whereby the catalytically active iron(IV)–oxo intermediate in the catalytic cycle undergoes an initial isomerisation assisted by an Arg residue in the substrate binding pocket, which then brings the oxo group in close contact with the methyl group of the alkylated DNA base. This enables a subsequent rate-determining hydrogen-atom abstraction on competitive σ-and π-pathways on a quintet spin-state surface. These findings give evidence of different locations of the oxygen and substrate binding channels in the enzyme and the origin of the separation of the oxygen-bound intermediates in the catalytic cycle from substrate. Our studies are compared with small model complexes and the effect of protein and environment on the kinetics and mechanism is explained. PMID:24339041

  18. Radiation and non-radiation damage to DNA. Onset of molecular instability and carcinogenesis. Theoretical explorations on DNA damage and repair

    International Nuclear Information System (INIS)

    Pinak, Miroslay; Bunta, J.K.

    2006-01-01

    The current work is focused on results of molecular dynamics simulations performed on two DNA damages: 8-oxoguanine as the most significant oxidative damage leading to transversion mutation cytosine-guanine→adenine-thymine', which is common mutation found in human cancer cells; and on the DNA strand break, the type of damage that is considered to be one of the most significant damage leading to genetic instability that may result in enhanced cell proliferation or carcinogenesis. Except the structural changes induced by these two lesions the role and importance of electrostatic energy in recognition process in which a respective repair enzyme recognizes damaged DNA site is also described. Among the significant results can be included the fact, that most of the damages on DNA alternate locally electronic state by modifying chemical and electron orbital configuration. This modified configuration may be represented outside DNA molecule as an enhanced electrostatic interaction with surrounding environment, that may signal the presence of the damaged site toward the repair enzyme. Work on the DNA strand break shows that open valences at broken strand ends are quickly filled by the electrons generated during radiolysis. Results of simulation indicate a local instability of hydrogen bonds between complementary bases. (author)

  19. Multipurpose expert-robot system model for control, diagnosis, maintenance, and repairs at the steam generators of the NPP

    International Nuclear Information System (INIS)

    Popa, I.

    1994-01-01

    The paper presents the model concept for a multipurpose expert-robot system for control, diagnosis, forecast, maintenance, and repairs at the steam generators of CANDU type nuclear power plants. The system has two separate parts: the expert system and the robot (manipulator) system. These parts compose a hierarchic structure with the expert system on the upper level. The expert system has a blackboard architecture, to which tree interfaces with the robot system, with the control system of the NPP and with the methods and techniques of control, maintenance and repairs system of the steam generator are added. Due to complex nature of its activities the expert-robot system model combines the deterministic type reasons with probabilistic, fuzzy, and neural-networks type ones. The information that enter the expert system comes from the robot system, from process, from user, and human expert. The information that enter robot system comes from the expert system, from the human operator (when connected) and from process. Control maintenance and repair operations take place by means of the robot system that can be monitored either directly by the expert system or by the human operator who follows its activity. All these activities are performed in parallel with the adequate information of the expert system directly, by the human operator, about the status parameters and, possibly, operating parameters of the steam generator components. The expert-robot system can work independently, but it can be connected and integrated in the control system of NPP, to take over and develop some of its functions. The activities concerning diagnosis and characterization of the state of steam generator components subsequent to control, as well as the forecast of their future behavior, are performed by means of the expert system. Due to these characteristics the expert-robot system can be used successfully in personnel training activities. (Author)

  20. Model System for Live Imaging of Neuronal Responses to Injury and Repair

    Directory of Open Access Journals (Sweden)

    Mathieu Gravel

    2011-11-01

    Full Text Available Although it has been well established that induction of growth-associated protein-43 (GAP-43 during development coincides with axonal outgrowth and early synapse formation, the existence of neuronal plasticity and neurite outgrowth in the adult central nervous system after injuries is more controversial. To visualize the processes of neuronal injury and repair in living animals, we generated reporter mice for bioluminescence and fluorescence imaging bearing the luc (luciferase and gfp (green fluorescent protein reporter genes under the control of the murine GAP-43 promoter. Reporter functionality was first observed during the development of transgenic embryos. Using in vivo bioluminescence and fluorescence imaging, we visualized induction of the GAP-43 signals from live embryos starting at E10.5, as well as neuronal responses to brain and peripheral nerve injuries (the signals peaked at 14 days postinjury. Moreover, three-dimensional analysis of the GAP-43 bioluminescent signal confirmed that it originated from brain structures affected by ischemic injury. The analysis of fluorescence signal at cellular level revealed colocalization between endogenous protein and the GAP-43-driven gfp transgene. Taken together, our results suggest that the GAP-43-luc/gfp reporter mouse represents a valid model system for real-time analysis of neurite outgrowth and the capacity of the adult nervous system to regenerate after injuries.

  1. Activation of Saccharomyces cerevisiae Mlh1-Pms1 Endonuclease in a Reconstituted Mismatch Repair System.

    Science.gov (United States)

    Smith, Catherine E; Bowen, Nikki; Graham, William J; Goellner, Eva M; Srivatsan, Anjana; Kolodner, Richard D

    2015-08-28

    Previous studies reported the reconstitution of an Mlh1-Pms1-independent 5' nick-directed mismatch repair (MMR) reaction using Saccharomyces cerevisiae proteins. Here we describe the reconstitution of a mispair-dependent Mlh1-Pms1 endonuclease activation reaction requiring Msh2-Msh6 (or Msh2-Msh3), proliferating cell nuclear antigen (PCNA), and replication factor C (RFC) and a reconstituted Mlh1-Pms1-dependent 3' nick-directed MMR reaction requiring Msh2-Msh6 (or Msh2-Msh3), exonuclease 1 (Exo1), replication protein A (RPA), RFC, PCNA, and DNA polymerase δ. Both reactions required Mg(2+) and Mn(2+) for optimal activity. The MMR reaction also required two reaction stages in which the first stage required incubation of Mlh1-Pms1 with substrate DNA, with or without Msh2-Msh6 (or Msh2-Msh3), PCNA, and RFC but did not require nicking of the substrate, followed by a second stage in which other proteins were added. Analysis of different mutant proteins demonstrated that both reactions required a functional Mlh1-Pms1 endonuclease active site, as well as mispair recognition and Mlh1-Pms1 recruitment by Msh2-Msh6 but not sliding clamp formation. Mutant Mlh1-Pms1 and PCNA proteins that were defective for Exo1-independent but not Exo1-dependent MMR in vivo were partially defective in the Mlh1-Pms1 endonuclease and MMR reactions, suggesting that both reactions reflect the activation of Mlh1-Pms1 seen in Exo1-independent MMR in vivo. The availability of this reconstituted MMR reaction should now make it possible to better study both Exo1-independent and Exo1-dependent MMR. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  2. DNA-Enabled Integrated Molecular Systems for Computation and Sensing

    Science.gov (United States)

    2014-05-21

    Computational devices can be chemically conjugated to different strands of DNA that are then self-assembled according to strict Watson − Crick binding rules... DNA -Enabled Integrated Molecular Systems for Computation and Sensing Craig LaBoda,† Heather Duschl,† and Chris L. Dwyer*,†,‡ †Department of...guided folding of DNA , inspired by nature, allows designs to manipulate molecular-scale processes unlike any other material system. Thus, DNA can be

  3. Genetic defects in DNA repair system and enhancement of intergenote transformation efficiency in Bacillus subtilis Marburg

    International Nuclear Information System (INIS)

    Matsumoto, K.; Takahashi, H.; Saito, H.; Ikeda, Y.

    1978-01-01

    Mechanisms of inefficiency in heterospecies transformation were studied with a transformation system consisting of Bacillus subtilis 168TI (trpC2thy) as recipient and of DNA prepared from partially hybrid strains of B. subtilis which had incorporated trp + DNA of B. amyloliquefaciens 203 (formerly, B. megaterium 203) in the chromosome (termed intergenote). The intergenote transformation was not so efficient as the corresponding homospecies transformation and the efficiency appeared to relate inversely with the length of heterologous portion in the intergenote. When a variety of ultraviolet light (UV) sensitive mutants, deficient in host-cell reactivation capacity, were used as recipients for the intergenote transformation, 2 out of 16 mutants exhibited significantly enhanced transformation efficiency of the trpC marker. Genetic studies by transformation showed that the trait relating to the enhancement of intergenote-transformation efficiency was always associated with the UV sensitivity, suggesting that these two traits are determined by a single gene. The efficiency of intergenote transformation was highly affected also by DNA concentration; the lower the concentration, the less the efficiency. When, however, the UV sensitive mutant was used as recipient, the effect of DNA concentration was largely diminished, suggesting the reduction of DNA-inactivating activity in the UV sensitive recipient. These results were discussed in relation to a possible excision-repair system selectively correcting the mismatched DNA in the course of intergenote transformation. (orig.) [de

  4. Evolution and adaptation in Pseudomonas aeruginosa biofilms driven by mismatch repair system-deficient mutators.

    Directory of Open Access Journals (Sweden)

    Adela M Luján

    Full Text Available Pseudomonas aeruginosa is an important opportunistic pathogen causing chronic airway infections, especially in cystic fibrosis (CF patients. The majority of the CF patients acquire P. aeruginosa during early childhood, and most of them develop chronic infections resulting in severe lung disease, which are rarely eradicated despite intensive antibiotic therapy. Current knowledge indicates that three major adaptive strategies, biofilm development, phenotypic diversification, and mutator phenotypes [driven by a defective mismatch repair system (MRS], play important roles in P. aeruginosa chronic infections, but the relationship between these strategies is still poorly understood. We have used the flow-cell biofilm model system to investigate the impact of the mutS associated mutator phenotype on development, dynamics, diversification and adaptation of P. aeruginosa biofilms. Through competition experiments we demonstrate for the first time that P. aeruginosa MRS-deficient mutators had enhanced adaptability over wild-type strains when grown in structured biofilms but not as planktonic cells. This advantage was associated with enhanced micro-colony development and increased rates of phenotypic diversification, evidenced by biofilm architecture features and by a wider range and proportion of morphotypic colony variants, respectively. Additionally, morphotypic variants generated in mutator biofilms showed increased competitiveness, providing further evidence for mutator-driven adaptive evolution in the biofilm mode of growth. This work helps to understand the basis for the specific high proportion and role of mutators in chronic infections, where P. aeruginosa develops in biofilm communities.

  5. NAXE Mutations Disrupt the Cellular NAD(P)HX Repair System and Cause a Lethal Neurometabolic Disorder of Early Childhood.

    Science.gov (United States)

    Kremer, Laura S; Danhauser, Katharina; Herebian, Diran; Petkovic Ramadža, Danijela; Piekutowska-Abramczuk, Dorota; Seibt, Annette; Müller-Felber, Wolfgang; Haack, Tobias B; Płoski, Rafał; Lohmeier, Klaus; Schneider, Dominik; Klee, Dirk; Rokicki, Dariusz; Mayatepek, Ertan; Strom, Tim M; Meitinger, Thomas; Klopstock, Thomas; Pronicka, Ewa; Mayr, Johannes A; Baric, Ivo; Distelmaier, Felix; Prokisch, Holger

    2016-10-06

    To safeguard the cell from the accumulation of potentially harmful metabolic intermediates, specific repair mechanisms have evolved. APOA1BP, now renamed NAXE, encodes an epimerase essential in the cellular metabolite repair for NADHX and NADPHX. The enzyme catalyzes the epimerization of NAD(P)HX, thereby avoiding the accumulation of toxic metabolites. The clinical importance of the NAD(P)HX repair system has been unknown. Exome sequencing revealed pathogenic biallelic mutations in NAXE in children from four families with (sub-) acute-onset ataxia, cerebellar edema, spinal myelopathy, and skin lesions. Lactate was elevated in cerebrospinal fluid of all affected individuals. Disease onset was during the second year of life and clinical signs as well as episodes of deterioration were triggered by febrile infections. Disease course was rapidly progressive, leading to coma, global brain atrophy, and finally to death in all affected individuals. NAXE levels were undetectable in fibroblasts from affected individuals of two families. In these fibroblasts we measured highly elevated concentrations of the toxic metabolite cyclic-NADHX, confirming a deficiency of the mitochondrial NAD(P)HX repair system. Finally, NAD or nicotinic acid (vitamin B3) supplementation might have therapeutic implications for this fatal disorder. Copyright © 2016 American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.

  6. Genetic characterization of cells of homocystinuria patients with disrupted DNA repair system

    International Nuclear Information System (INIS)

    Sinel'shchikova, T.A.; L'vova, G.N.; Shoniya, N.N.; Zasukhina, G.D.

    1986-01-01

    Fibroblasts obtained from biopsy material and lymphocytes of patients with homocystinuria were investigated for repair activity according to the following criteria: rejoined DNA breaks, induced by 4-nitroquinoline-1-oxide and γ-radiation; indices of reactivation and induced mutagenesis of smallpox vaccine virus treated with these mutagens. In lymphocytes a defect of DNA repair was observed according to all criteria investigated. During passage of fibroblast cultures, inhibition of repair activity of cells was preserved according to γ-type. Increase in the number of spontaneous and γ-induced mutations of virus was noted according to degree of passage of fibroblasts

  7. Molecular cloning of a mouse DNA repair gene that complements the defect of group-A xeroderma pigmentosum

    International Nuclear Information System (INIS)

    Tanaka, K.; Satokata, I.; Ogita, Z.; Uchida, T.; Okada, Y.

    1989-01-01

    For isolation of the gene responsible for xeroderma pigmentosum (XP) complementation group A, plasmid pSV2gpt and genomic DNA from a mouse embryo were cotransfected into XP2OSSV cells, a group-A XP cell line. Two primary UV-resistant XP transfectants were isolated from about 1.6 X 10(5) pSV2gpt-transformed XP colonies. pSV2gpt and genomic DNA from the primary transfectants were again cotransfected into XP2OSSV cells and a secondary UV-resistant XP transfectant was obtained by screening about 4.8 X 10(5) pSV2gpt-transformed XP colonies. The secondary transfectant retained fewer mouse repetitive sequences. A mouse gene that complements the defect of XP2OSSV cells was cloned into an EMBL3 vector from the genome of a secondary transfectant. Transfections of the cloned DNA also conferred UV resistance on another group-A XP cell line but not on XP cell lines of group C, D, F, or G. Northern blot analysis of poly(A)+ RNA with a subfragment of cloned mouse DNA repair gene as the probe revealed that an approximately 1.0 kilobase mRNA was transcribed in the donor mouse embryo and secondary transfectant, and approximately 1.0- and approximately 1.3-kilobase mRNAs were transcribed in normal human cells, but none of these mRNAs was detected in three strains of group-A XP cells. These results suggest that the cloned DNA repair gene is specific for group-A XP and may be the mouse homologue of the group-A XP human gene

  8. Interactive analysis of systems biology molecular expression data

    Directory of Open Access Journals (Sweden)

    Prabhakar Sunil

    2008-02-01

    Full Text Available Abstract Background Systems biology aims to understand biological systems on a comprehensive scale, such that the components that make up the whole are connected to one another and work through dependent interactions. Molecular correlations and comparative studies of molecular expression are crucial to establishing interdependent connections in systems biology. The existing software packages provide limited data mining capability. The user must first generate visualization data with a preferred data mining algorithm and then upload the resulting data into the visualization package for graphic visualization of molecular relations. Results Presented is a novel interactive visual data mining application, SysNet that provides an interactive environment for the analysis of high data volume molecular expression information of most any type from biological systems. It integrates interactive graphic visualization and statistical data mining into a single package. SysNet interactively presents intermolecular correlation information with circular and heatmap layouts. It is also applicable to comparative analysis of molecular expression data, such as time course data. Conclusion The SysNet program has been utilized to analyze elemental profile changes in response to an increasing concentration of iron (Fe in growth media (an ionomics dataset. This study case demonstrates that the SysNet software is an effective platform for interactive analysis of molecular expression information in systems biology.

  9. Application of a System-Based Inventory Model to Marine Corps Repairable Parts

    National Research Council Canada - National Science Library

    Barnett, Craig

    2001-01-01

    ... isolation of the inventories and because of mathematical flaws in the Marine Corps' sparing methodology The Marine Corps is seeking to centralize the management of secondary repairables and is considering...

  10. The effect of caffeine on repair systems in oocytes of Drosophila melanogaster

    International Nuclear Information System (INIS)

    Mendelson, D.

    1976-01-01

    Genetic analysis was performed to locate the factors involved in the defective repair mechanism in the oocytes of Ubx e 4 /Payne ca females. The results demonstrate that at least three third-chromosome factors may be involved in the control of maternal repair, the two most effective ones being located on the right arm of the third chromosome, one near the Ubx locus and the other near the ca locus

  11. DNA repair genes

    International Nuclear Information System (INIS)

    Morimyo, Mitsuoki

    1995-01-01

    Fission yeast S. pombe is assumed to be a good model for cloning of human DNA repair genes, because human gene is normally expressed in S. pombe and has a very similar protein sequence to yeast protein. We have tried to elucidate the DNA repair mechanisms of S. pombe as a model system for those of mammals. (J.P.N.)

  12. Energy-dissipating and self-repairing SMA-ECC composite material system

    International Nuclear Information System (INIS)

    Li, Xiaopeng; Li, Mo; Song, Gangbing

    2015-01-01

    Structural component ductility and energy dissipation capacity are crucial factors for achieving reinforced concrete structures more resistant to dynamic loading such as earthquakes. Furthermore, limiting post-event residual damage and deformation allows for immediate re-operation or minimal repairs. These desirable characteristics for structural ‘resilience’, however, present significant challenges due to the brittle nature of concrete, its deformation incompatibility with ductile steel, and the plastic yielding of steel reinforcement. Here, we developed a new composite material system that integrates the unique ductile feature of engineered cementitious composites (ECC) with superelastic shape memory alloy (SMA). In contrast to steel reinforced concrete (RC) and SMA reinforced concrete (SMA-RC), the SMA-ECC beams studied in this research exhibited extraordinary energy dissipation capacity, minimal residual deformation, and full self-recovery of damage under cyclic flexural loading. We found that the tensile strain capacity of ECC, tailored up to 5.5% in this study, allows it to work compatibly with superelastic SMA. Furthermore, the distributed microcracking damage mechanism in ECC is critical for sufficient and reliable recovery of damage upon unloading. This research demonstrates the potential of SMA-ECC for improving resilience of concrete structures under extreme hazard events. (paper)

  13. Cell and biomolecule delivery for tissue repair and regeneration in the central nervous system.

    Science.gov (United States)

    Elliott Donaghue, Irja; Tam, Roger; Sefton, Michael V; Shoichet, Molly S

    2014-09-28

    Tissue engineering frequently involves cells and scaffolds to replace damaged or diseased tissue. It originated, in part, as a means of effecting the delivery of biomolecules such as insulin or neurotrophic factors, given that cells are constitutive producers of such therapeutic agents. Thus cell delivery is intrinsic to tissue engineering. Controlled release of biomolecules is also an important tool for enabling cell delivery since the biomolecules can enable cell engraftment, modulate inflammatory response or otherwise benefit the behavior of the delivered cells. We describe advances in cell and biomolecule delivery for tissue regeneration, with emphasis on the central nervous system (CNS). In the first section, the focus is on encapsulated cell therapy. In the second section, the focus is on biomolecule delivery in polymeric nano/microspheres and hydrogels for the nerve regeneration and endogenous cell stimulation. In the third section, the focus is on combination strategies of neural stem/progenitor cell or mesenchymal stem cell and biomolecule delivery for tissue regeneration and repair. In each section, the challenges and potential solutions associated with delivery to the CNS are highlighted. Copyright © 2014 Elsevier B.V. All rights reserved.

  14. Probing Interactions in Complex Molecular Systems through Ordered Assembly

    International Nuclear Information System (INIS)

    De Yoreo, J.J.; Bartelt, M.C.; Orme, C.A.; Villacampa, A.; Weeks, B.L.; Miller, A.E.

    2002-01-01

    Emerging from the machinery of epitaxial science and chemical synthesis, is a growing emphasis on development of self-organized systems of complex molecular species. The nature of self-organization in these systems spans the continuum from simple crystallization of large molecules such as dendrimers and proteins, to assembly into large organized networks of nanometer-scale structures such as quantum dots or nanoparticles. In truth, self-organization in complex molecular systems has always been a central feature of many scientific disciplines including fields as diverse as structural biology, polymer science and geochemistry. But over the past decade, changes in those fields have often been marked by the degree to which researchers are using molecular-scale approaches to understand the hierarchy of structures and processes driven by this ordered assembly. At the same time, physical scientists have begun to use their knowledge of simple atomic and molecular systems to fabricate synthetic self-organized systems. This increasing activity in the field of self-organization is testament to the success of the physical and chemical sciences in building a detailed understanding of crystallization and epitaxy in simple atomic and molecular systems, one that is soundly rooted in thermodynamics and chemical kinetics. One of the fundamental challenges of chemistry and materials science in the coming decades is to develop a similarly well-founded physical understanding of assembly processes in complex molecular systems. Over the past five years, we have successfully used in situ atomic force microscopy (AFM) to investigate the physical controls on single crystal epitaxy from solutions for a wide range of molecular species. More recently, we have combined this method with grazing incidence X-ray diffraction and kinetic Monte Carlo modeling in order to relate morphology to surface atomic structure and processes. The purpose of this proposal was to extend this approach to assemblies

  15. The development of robotic system for inspecting and repairing NPP primary coolant system of high-level radioactive environment

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Seung Ho; Kim, Ki Ho; Jung, Seung Ho; Kim, Byung Soo; Hwang, Suk Yeoung; Kim, Chang Hoi; Seo, Yong Chil; Lee, Young Kwang; Lee, Yong Bum; Cho, Jai Wan; Lee, Jae Kyung; Lee, Yong Deok

    1997-07-01

    This project aims at developing a robotic system to automatically handle inspection and maintenance of NPP safety-related facilities in high-level radioactive environment. This robotic system under development comprises two robots depending on application fields - a mobile robot and multi-functional robot. The mobile robot is designed to be used in the area of primary coolant system during the operation of NPP. This robot enables to overcome obstacles and perform specified tasks in unstructured environment. The multi-functional robot is designed for performing inspection and maintenance tasks of steam generator and nuclear reactor vessel during the overhaul periods of NPP. Nuclear facilities can be inspected and repaired all the time by use of both the mobile robot and the multi-functional robot. Human operator, by teleoperation, monitors the movements of such robots located at remote task environment via video cameras and controls those remotely generating desired commands via master manipulator. We summarize the technology relating to the application of the mobile robot to primary coolant system environment, the applicability of the mobile robot through 3D graphic simulation, the design of the mobile robot, the design of its radiation-hardened controller. We also describe the mechanical design, modeling, and control system of the multi-functional robot. Finally, we present the design of the force-reflecting master and the modeling of virtual task environment for a training simulator. (author). 47 refs., 16 tabs., 43 figs.

  16. The development of robotic system for inspecting and repairing NPP primary coolant system of high-level radioactive environment

    International Nuclear Information System (INIS)

    Kim, Seung Ho; Kim, Ki Ho; Jung, Seung Ho; Kim, Byung Soo; Hwang, Suk Yeoung; Kim, Chang Hoi; Seo, Yong Chil; Lee, Young Kwang; Lee, Yong Bum; Cho, Jai Wan; Lee, Jae Kyung; Lee, Yong Deok.

    1997-07-01

    This project aims at developing a robotic system to automatically handle inspection and maintenance of NPP safety-related facilities in high-level radioactive environment. This robotic system under development comprises two robots depending on application fields - a mobile robot and multi-functional robot. The mobile robot is designed to be used in the area of primary coolant system during the operation of NPP. This robot enables to overcome obstacles and perform specified tasks in unstructured environment. The multi-functional robot is designed for performing inspection and maintenance tasks of steam generator and nuclear reactor vessel during the overhaul periods of NPP. Nuclear facilities can be inspected and repaired all the time by use of both the mobile robot and the multi-functional robot. Human operator, by teleoperation, monitors the movements of such robots located at remote task environment via video cameras and controls those remotely generating desired commands via master manipulator. We summarize the technology relating to the application of the mobile robot to primary coolant system environment, the applicability of the mobile robot through 3D graphic simulation, the design of the mobile robot, the design of its radiation-hardened controller. We also describe the mechanical design, modeling, and control system of the multi-functional robot. Finally, we present the design of the force-reflecting master and the modeling of virtual task environment for a training simulator. (author). 47 refs., 16 tabs., 43 figs

  17. Improving the Repair Planning System for Mining Equipment on the Basis of Non-destructive Evaluation Data

    Science.gov (United States)

    Drygin, Michael; Kuryshkin, Nicholas

    2017-11-01

    The article tells about forming a new concept of scheduled preventive repair system of the equipment at coal mining enterprises, based on the use of modem non-destructive evaluation methods. The approach to the solution for this task is based on the system-oriented analysis of the regulatory documentation, non-destructive evaluation methods and means, experimental studies with compilation of statistics and subsequent grapho-analytical analysis. The main result of the work is a feasible explanation of using non-destructive evaluation methods within the current scheduled preventive repair system, their high efficiency and the potential of gradual transition to condition-based maintenance. In practice wide use of nondestructive evaluation means w;ill allow to reduce significantly the number of equipment failures and to repair only the nodes in pre-accident condition. Considering the import phase-out policy, the solution for this task will allow to adapt the SPR system to Russian market economy conditions and give the opportunity of commercial move by reducing the expenses for maintenance of Russian-made and imported equipment.

  18. Dependability estimation for non-Markov consecutive-k-out-of-n: F repairable systems by fast simulation

    International Nuclear Information System (INIS)

    Xiao Gang; Li Zhizhong; Li Ting

    2007-01-01

    A model of consecutive-k-out-of-n: F repairable system with non-exponential repair time distribution and (k-1)-step Markov dependence is introduced in this paper along with algorithms of three Monte Carlo methods, i.e. importance sampling, conditional expectation estimation and combination of the two methods, to estimate dependability of the non-Markov model including reliability, transient unavailability, MTTF, and MTBF. A numerical example is presented to demonstrate the efficiencies of above methods. The results show that combinational method has the highest efficiency for estimation of unreliability and unavailability, while conditional expectation estimation is the most efficient method for estimation of MTTF and MTBF. Conditional expectation estimation seems to have overall higher speedups in estimating dependability of such systems

  19. Comparison of the Mismatch Repair System between Primary and Metastatic Colorectal Cancers Using Immunohistochemistry

    Directory of Open Access Journals (Sweden)

    Jiyoon Jung

    2017-03-01

    Full Text Available Background Colorectal cancer (CRC is one of the most common malignancies worldwide. Approximately 10%–15% of the CRC cases have defective DNA mismatch repair (MMR genes. Although the high level of microsatellite instability status is a predictor of favorable outcome in primary CRC, little is known about its frequency and importance in secondary CRC. Immunohistochemical staining (IHC for MMR proteins (e.g., MLH1, MSH2, MSH6, and PMS2 has emerged as a useful technique to complement polymerase chain reaction (PCR analyses. Methods In this study, comparison between the MMR system of primary CRCs and paired liver and lung metastatic lesions was done using IHC and the correlation with clinical outcomes was also examined. Results Based on IHC, 7/61 primary tumors (11.4% showed deficient MMR systems, while 13/61 secondary tumors (21.3% showed deficiencies. In total, 44 cases showed proficient expression in both the primary and metastatic lesions. Three cases showed deficiencies in both the primary and paired metastatic lesions. In 10 cases, proficient expression was found only in the primary lesions, and not in the corresponding metastatic lesions. In four cases, proficient expression was detected in the secondary tumor, but not in the primary tumor. Conclusions Although each IHC result and the likely defective genes were not exactly matched between the primary and the metastatic tumors, identical results for primary and metastatic lesions were obtained in 77% of the cases (47/61. These data are in agreement with the previous microsatellite detection studies that used PCR and IHC.

  20. Ranking of small scale proposals for water system repair using the Rapid Impact Assessment Matrix (RIAM)

    Energy Technology Data Exchange (ETDEWEB)

    Shakib-Manesh, T.E.; Hirvonen, K.O.; Jalava, K.J.; Ålander, T.; Kuitunen, M.T., E-mail: markku.kuitunen@jyu.fi

    2014-11-15

    Environmental impacts of small scale projects are often assessed poorly, or not assessed at all. This paper examines the usability of the Rapid Impact Assessment Matrix (RIAM) as a tool to prioritize project proposals for small scale water restoration projects in relation to proposals' potential to improve the environment. The RIAM scoring system was used to assess and rank the proposals based on their environmental impacts, the costs of the projects to repair the harmful impacts, and the size of human population living around the sites. A four-member assessment group (The expert panel) gave the RIAM-scores to the proposals. The assumed impacts of the studied projects at the Eastern Finland water systems were divided into the ecological and social impacts. The more detailed assessment categories of the ecological impacts in this study were impacts on landscape, natural state, and limnology. The social impact categories were impacts to recreational use of the area, fishing, industry, population, and economy. These impacts were scored according to their geographical and social significance, their magnitude of change, their character, permanence, reversibility, and cumulativeness. The RIAM method proved to be an appropriate and recommendable method for the small-scale assessment and prioritizing of project proposals. If the assessments are well documented, the RIAM can be a method for easy assessing and comparison of the various kinds of projects. In the studied project proposals there were no big surprises in the results: the best ranks were received by the projects, which were assumed to return watersheds toward their original state.

  1. Ranking of small scale proposals for water system repair using the Rapid Impact Assessment Matrix (RIAM)

    International Nuclear Information System (INIS)

    Shakib-Manesh, T.E.; Hirvonen, K.O.; Jalava, K.J.; Ålander, T.; Kuitunen, M.T.

    2014-01-01

    Environmental impacts of small scale projects are often assessed poorly, or not assessed at all. This paper examines the usability of the Rapid Impact Assessment Matrix (RIAM) as a tool to prioritize project proposals for small scale water restoration projects in relation to proposals' potential to improve the environment. The RIAM scoring system was used to assess and rank the proposals based on their environmental impacts, the costs of the projects to repair the harmful impacts, and the size of human population living around the sites. A four-member assessment group (The expert panel) gave the RIAM-scores to the proposals. The assumed impacts of the studied projects at the Eastern Finland water systems were divided into the ecological and social impacts. The more detailed assessment categories of the ecological impacts in this study were impacts on landscape, natural state, and limnology. The social impact categories were impacts to recreational use of the area, fishing, industry, population, and economy. These impacts were scored according to their geographical and social significance, their magnitude of change, their character, permanence, reversibility, and cumulativeness. The RIAM method proved to be an appropriate and recommendable method for the small-scale assessment and prioritizing of project proposals. If the assessments are well documented, the RIAM can be a method for easy assessing and comparison of the various kinds of projects. In the studied project proposals there were no big surprises in the results: the best ranks were received by the projects, which were assumed to return watersheds toward their original state

  2. Energy conservation in molecular dynamics simulations of classical systems

    DEFF Research Database (Denmark)

    Toxværd, Søren; Heilmann, Ole; Dyre, J. C.

    2012-01-01

    Classical Newtonian dynamics is analytic and the energy of an isolated system is conserved. The energy of such a system, obtained by the discrete “Verlet” algorithm commonly used in molecular dynamics simulations, fluctuates but is conserved in the mean. This is explained by the existence...

  3. Selected technological problems of repair of hydraulic drive systems for shearer loaders with the example of A2V-107 pumps and SHT-630W motors

    Energy Technology Data Exchange (ETDEWEB)

    Kusak, E.; Paluch, J.

    1983-07-01

    Major elements of hydraulic drive systems as well as their wear and repair characteristics are described. Types of wear and standardized repair methods are comparatively evaluated. The evaluations are aimed at development of standardized procedures for use in large repair shops. The following stages of repair operations of A2V-107 pumps and SHT-630W motors are analyzed: disassembling hydraulic systems, washing and cleaning, classification of equipment elements (elements for scrapping and for regeneration), regeneration, assembling and final tests. The following regeneration methods are discussed: cutting, burnishing, bushing (e.g. the Heli Coil method), regeneration using copper, tin or zinc dusts and a temperature from 950 to 1,000 K under inert atmosphere, heat treatments. Methods are reviewed for comparative evaluations of repair efficiency and repair quality as well as documents used for recording repair in the shops. Economic aspects of using standardized procedures for repair of hydraulic equipment for shearer loaders are discussed and recommendations are made. (6 refs.)

  4. Repair of X-ray-induced single-strand breaks by a cell-free system

    International Nuclear Information System (INIS)

    Seki, Shuji; Ikeda, Shogo; Tsutui, Ken; Teraoka, Hirobumi

    1990-01-01

    Repair of X-ray-induced single-strand breaks of DNA was studied in vitro using an exonuclease purified from mouse ascites sarcoma (SR-C3H/He) cells. X-ray-dose-dependent unscheduled DNA synthesis was primed by the exonuclease. Repair of X-ray-induced single-strand breaks in pUC19 plasmid DNA was demonstrated by agarose gel electrophoresis after incubating the damaged DNA with the exonuclease, DNA polymerase (Klenow fragment of DNA polymerase I or DNA polymerase β purified from SR-C3H/He cells), four deoxynucleoside triphosphates, ATP and DNA ligase (T4 DNA ligase or DNA ligase I purified from calf thymus). The present results suggested that the exonuclease is involved in the initiation of repair of X-ray-induced single-strand breaks in removing 3' ends of X-ray-damaged DNA. (author)

  5. Outcomes of Endovascular Aneurysm Repair using the Ovation Stent Graft System in Adverse Anatomy.

    Science.gov (United States)

    Greaves, Nicholas S; Moore, Aiden; Seriki, Dare; Ghosh, Jonathan

    2018-04-01

    The aim was the evaluation of mid-term efficacy and safety outcome measures for the Ovation (Endologix, Santa Rosa, CA, USA) stent graft system in the management of infrarenal abdominal aortic aneurysms (iAAA) with adverse anatomy. A retrospective observational study of all patients undergoing elective iAAA repair was carried out from 2012 to 2017 using Ovation Prime or iX stent grafts with a minimum of 3 months follow-up at a single UK vascular centre. Post-operative surveillance involved computed tomography scans at 3 months and 1 year, with duplex ultrasound yearly thereafter. Outcome measures were established with retrospective analysis of pre- and post-operative imaging, and included peri-operative mortality, major adverse events, limb complications, aneurysm diameter change, and endoleak rates. All patients were within Ovation instructions for use (IFU), and assessment was made to determine whether aneurysms had anatomical features considered adverse for other commonly used stent graft platforms. Ovation stent grafts were implanted in 52 patients (79% male, mean age 75.7 years) with a mean aneurysm diameter of 62.5 mm (range 55-107 mm). There was 100% technical deployment success. The 30 day mortality was 0% and there was no aneurysm related mortality during follow-up (median 24 months, range 3-48 months). There were no type I or III endoleaks, but 19% developed type II endoleaks with one patient requiring re-intervention. No iliac limb occlusions were identified but one case required relining for limb kinking. All 52 cases were within the IFU for Ovation but only 12% met the IFU criteria for the Cook and Medtronic devices. The mid-term experience with Ovation demonstrates safe, durable treatment of iAAAs, including those with unfavourable anatomy, frequently off IFU for other commonly used devices. Copyright © 2017 European Society for Vascular Surgery. Published by Elsevier B.V. All rights reserved.

  6. The effect of caffeine on repair systems in oocytes of Drosophila melanogaster

    International Nuclear Information System (INIS)

    Mendelson, D.

    1976-01-01

    Irradiated males were mated to females that had received treatment with caffeine or honey (by feeding), and the frequencies of sex-chromosome losses and chromosome rearrangements induced in mature spermatozoa of the males were compared. Caffeine treatment led to an enhancement of the frequencies of sex-chromosome loss and a decrease in those of rearrangements. These findings can be interpreted on the assumption that caffeine inhibits repair and misrepair processes that are active in the oocytes. Caffeine treatment administered to one of the female stocks used in these studies was without any effect, presumably because of the absence of a caffeine-sensitive repair mechanism in the oocytes

  7. Simulation based analysis and an application to an offshore oil and gas production system of the Natvig measures of component importance in repairable systems

    International Nuclear Information System (INIS)

    Natvig, Bent; Eide, Kristina A.; Gasemyr, Jorund; Huseby, Arne B.; Isaksen, Stefan L.

    2009-01-01

    In the present paper the Natvig measures of component importance for repairable systems, and its extended version are analyzed for two three-component systems and a bridge system. The measures are also applied to an offshore oil and gas production system. According to the extended version of the Natvig measure a component is important if both by failing it strongly reduces the expected system uptime and by being repaired it strongly reduces the expected system downtime. The results include a study of how different distributions affect the ranking of the components. All numerical results are computed using discrete event simulation. In a companion paper [Huseby AB, Eide KA, Isaksen SL, Natvig B, Gasemyr, J. Advanced discrete event simulation methods with application to importance measure estimation. 2009, submitted for publication] the advanced simulation methods needed in these calculations are described.

  8. Endoscopic augmentation of the lower esophageal sphincter for the treatment of gastroesophageal reflux disease: Multicenter study of the gatekeeper reflux repair system

    NARCIS (Netherlands)

    Fockens, P.; Bruno, M. J.; Gabbrielli, A.; Odegaard, S.; Hatlebakk, J.; Allescher, H. D.; Rösch, T.; Rhodes, M.; Bastid, C.; Rey, J.; Boyer, J.; Muehldorffer, S.; van den Hombergh, U.; Costamagna, G.

    2004-01-01

    Background and Study Aims: The safety and effectiveness of the Gatekeeper Reflux Repair System (Medtronic Europe, Tolochenaz, Switzerland) in the treatment of gastroesophageal reflux disease (GERD) was evaluated. This new, reversible treatment modality involves the endoscopic introduction of

  9. DNA repair and the genetic control of radiosensitivity in yeast

    International Nuclear Information System (INIS)

    Haynes, R.H.

    1975-01-01

    The following topics are discussed: advantages of yeasts for easily manipulated model systems for studies on molecular biology of eukaryotes; induction of x-ray-resistant mutants by radiations and chemicals; genetics of uv-sensitive mutants; loci of genes affecting radiosensitivity; gene interactions in multiple mutants; liquid-holding recovery; mitotic and meiotic recombination; and repair of yeast mitochondrial DNA

  10. Clustered DNA lesions containing 5-formyluracil and AP site: repair via the BER system.

    Directory of Open Access Journals (Sweden)

    Ekaterina A Belousova

    Full Text Available Lesions in the DNA arise under ionizing irradiation conditions or various chemical oxidants as a single damage or as part of a multiply damaged site within 1-2 helical turns (clustered lesion. Here, we explored the repair opportunity of the apurinic/apyrimidinic site (AP site composed of the clustered lesion with 5-formyluracil (5-foU by the base excision repair (BER proteins. We found, that if the AP site is shifted relative to the 5-foU of the opposite strand, it could be repaired primarily via the short-patch BER pathway. In this case, the cleavage efficiency of the AP site-containing DNA strand catalyzed by human apurinic/apyrimidinic endonuclease 1 (hAPE1 decreased under AP site excursion to the 3'-side relative to the lesion in the other DNA strand. DNA synthesis catalyzed by DNA polymerase lambda was more accurate in comparison to the one catalyzed by DNA polymerase beta. If the AP site was located exactly opposite 5-foU it was expected to switch the repair to the long-patch BER pathway. In this situation, human processivity factor hPCNA stimulates the process.

  11. Complex catalysts from self-repairing ensembles to highly reactive air-based oxidation systems

    Science.gov (United States)

    Craig L. Hill; Laurent Delannoy; Dean C. Duncan; Ira A. Weinstock; Roman F. Renneke; Richard S. Reiner; Rajai H. Atalla; Jong Woo Han; Daniel A. Hillesheim; Rui Cao; Travis M. Anderson; Nelya M. Okun; Djamaladdin G. Musaev; Yurii V. Geletii

    2007-01-01

    Progress in four interrelated catalysis research efforts in our laboratory are summarized: (1) catalytic photochemical functionalization of unactivated CeH bonds by polyoxometalates (POMs); (2) self-repairing catalysts; (3) catalysts for air-based oxidations under ambient conditions; and (4) terminal oxo complexes of the late-transition metal elements and their...

  12. The development of remote repairing system, decontamination and in-cell remote inspection equipment

    International Nuclear Information System (INIS)

    Ishibashi, Yuzo; Toyoda, Osamu; Haginoya, Isao; Yamamoto, Ryuichi; Tanaka, Yasumasa

    1993-01-01

    PNC has been developing remote repair and inspection technologies for in-cell components in reprocessing Plants. In this report, several remote technologies such as remote dismantling and removal, decontamination, remote pipe maintenance and remote in-cell inspection equipment are described. (author)

  13. Involvement of the DNA mismatch repair system in cisplatin sensitivity of testicular germ cell tumours.

    Science.gov (United States)

    Rudolph, Christiane; Melau, Cecilie; Nielsen, John E; Vile Jensen, Kristina; Liu, Dekang; Pena-Diaz, Javier; Rajpert-De Meyts, Ewa; Rasmussen, Lene Juel; Jørgensen, Anne

    2017-08-01

    Testicular germ cell tumours (TGCT) are highly sensitive to cisplatin-based chemotherapy, but patients with tumours containing differentiated teratoma components are less responsive to this treatment. The cisplatin sensitivity in TGCT has previously been linked to the embryonic phenotype in the majority of tumours, although the underlying mechanism largely remains to be elucidated. The aim of this study was to investigate the role of the DNA mismatch repair (MMR) system in the cisplatin sensitivity of TGCT. The expression pattern of key MMR proteins, including MSH2, MSH6, MLH1 and PMS2, were investigated during testis development and in the pathogenesis of TGCT, including germ cell neoplasia in situ (GCNIS). The TGCT-derived cell line NTera2 was differentiated using retinoic acid (10 μM, 6 days) after which MMR protein expression and activity, as well as cisplatin sensitivity, were investigated in both undifferentiated and differentiated cells. Finally, the expression of MSH2 was knocked down by siRNA in NTera2 cells after which the effect on cisplatin sensitivity was examined. MMR proteins were expressed in proliferating cells in the testes, while in malignant germ cells MMR protein expression was found to coincide with the expression of the pluripotency factor OCT4, with no or low expression in the more differentiated yolk sac tumours, choriocarcinomas and teratomas. In differentiated NTera2 cells we found a significantly (p cisplatin sensitivity, compared to undifferentiated NTera2 cells. Also, we found that partial knockdown of MSH2 expression in undifferentiated NTera2 cells resulted in a significantly (p cisplatin sensitivity. This study reports, for the first time, expression of the MMR system in fetal gonocytes, from which GCNIS cells are derived. Our findings in primary TGCT specimens and TGCT-derived cells suggest that a reduced sensitivity to cisplatin in differentiated TGCT components could result from a reduced expression of MMR proteins, in

  14. Research trends in radiobiology since 40 years. a new approach: the enzymatic repair function of DNA, internal factor in evolution of biological systems under irradiation

    International Nuclear Information System (INIS)

    Mouton, R.

    1968-01-01

    In the first part of the report, the author attempts to draw an historical scheme of successive research working hypotheses in radiobiology since 1924. Less than a generation ago the effect of radiation exposure were viewed as being direct, immediate, irreparable and unmodifiable. Now it is generally accepted that radiation lesion can also be indirect, delayed, reparable and often modified with appropriate chemical or biochemical treatment. It was however in 1962-1964 that came the decisive breakthrough in radiobiology with the discovery that the cell possesses a natural active self-defense mechanism against whatever stress would affect the integrity of the genetic message contained in the DNA structure itself. The existence of what could be considered as a fourth DNA function i.e. self-repair by enzymatic action under genetic control-brings at least to radiobiology the missing molecular biology basis it needed to get out of its 'phenomenological night' after abandon of the generalization of Lea's theory through lack of experimental evidence. In the second part, which is a prospective one, the author tries to set an enlarged synthesis considering the possible role of DNA repair system not only in cell survival - in presence or absence of dose modifiers or mutagens - but also in the artificial and natural evolution of biological system exposed to sub-lethal doses of radiation. Most recent data from the literature fit well with what must be still considered as a general working hypothesis. Studies dealing with phenotypic and genotypic characters linked with the acquisition of gamma and UV radiation resistance in 'Escherichia coli K12' has been started by the author, in collaboration with O. Tremeau, in order to bring a new experimental contribution in this respect. (author) [fr

  15. Multi-Scale Molecular Deconstruction of the Serotonin Neuron System.

    Science.gov (United States)

    Okaty, Benjamin W; Freret, Morgan E; Rood, Benjamin D; Brust, Rachael D; Hennessy, Morgan L; deBairos, Danielle; Kim, Jun Chul; Cook, Melloni N; Dymecki, Susan M

    2015-11-18

    Serotonergic (5HT) neurons modulate diverse behaviors and physiology and are implicated in distinct clinical disorders. Corresponding diversity in 5HT neuronal phenotypes is becoming apparent and is likely rooted in molecular differences, yet a comprehensive approach characterizing molecular variation across the 5HT system is lacking, as is concomitant linkage to cellular phenotypes. Here we combine intersectional fate mapping, neuron sorting, and genome-wide RNA-seq to deconstruct the mouse 5HT system at multiple levels of granularity-from anatomy, to genetic sublineages, to single neurons. Our unbiased analyses reveal principles underlying system organization, 5HT neuron subtypes, constellations of differentially expressed genes distinguishing subtypes, and predictions of subtype-specific functions. Using electrophysiology, subtype-specific neuron silencing, and conditional gene knockout, we show that these molecularly defined 5HT neuron subtypes are functionally distinct. Collectively, this resource classifies molecular diversity across the 5HT system and discovers sertonergic subtypes, markers, organizing principles, and subtype-specific functions with potential disease relevance. Copyright © 2015 Elsevier Inc. All rights reserved.

  16. Development and applications of Bacillus subtilis test systems for mutagens, involving DNA-repair deficiency and suppressible auxotrophic mutations

    International Nuclear Information System (INIS)

    Tanooka, H.

    1977-01-01

    A mutagen-tester of Bacillus subtilis was constructed and tested with known carcinogens. The parental strain HA101 of Okubo and Yanagida carrying suppressible nonsense mutations in his and met genes was transformed to carry an excision-repair deficiency mutation. The constructed strain TKJ5211 showed a 20-30-fold higher sensitivity for His + reversion than the parental strain when treated with UV and UV-mimetic chemicals but unchanged mutation frequency with X-rays and methyl methanesulfonate. The tester strain was used in a spot test of 30 selected chemicals and also for testing with liver homogenate activation. The results showed an almost equivalent but somewhat broader detection spectrum than the Salmonella typhimurium TA100 system. Another test method used a pair of B. subtilis strains differing in their DNA-repair capacity, i.e. the most UV-sensitive mutant HJ-15 and a wild-type strain, to detect repair-dependent DNA damage produced by chemicals. Spores could be used in either test

  17. The Influence of Hepatitis C Virus Therapy on the DNA Base Excision Repair System of Peripheral Blood Mononuclear Cells.

    Science.gov (United States)

    Czarny, Piotr; Merecz-Sadowska, Anna; Majchrzak, Kinga; Jabłkowski, Maciej; Szemraj, Janusz; Śliwiński, Tomasz; Karwowski, Bolesław

    2017-07-01

    Hepatitis C virus (HCV) can infect extrahepatic tissues, including lymphocytes, creating reservoir of the virus. Moreover, HCV proteins can interact with DNA damage response proteins of infected cells. In this article we investigated the influence of the virus infection and a new ombitasvir/paritaprevir/ritonavir ± dasabuvir ± ribavirin (OBV/PTV/r ± DSV ± RBV) anti-HCV therapy on the PBMCs (peripheral blood mononuclear cells, mainly lymphocytes) DNA base excision repair (BER) system. BER protein activity was analyzed in the nuclear and mitochondrial extracts (NE and ME) of PBMC isolated from patients before and after therapy, and from subjects without HCV, using modeled double-strand DNA, with 2'-deoxyuridine substitution as the DNA damage. The NE and ME obtained from patients before therapy demonstrated lower efficacy of 2'-deoxyuridine removal and DNA repair polymerization than those of the control group or patients after therapy. Moreover, the extracts from the patients after therapy had similar activity to those from the control group. However, the efficacy of apurinic/apyrimidinic site excision in NE did not differ between the studied groups. We postulate that infection of lymphocytes by the HCV can lead to a decrease in the activity of BER enzymes. However, the use of novel therapy results in the improvement of glycosylase activity as well as the regeneration of endonuclease and other crucial repair enzymes.

  18. Discrete event simulation methods applied to advanced importance measures of repairable components in multistate network flow systems

    International Nuclear Information System (INIS)

    Huseby, Arne B.; Natvig, Bent

    2013-01-01

    Discrete event models are frequently used in simulation studies to model and analyze pure jump processes. A discrete event model can be viewed as a system consisting of a collection of stochastic processes, where the states of the individual processes change as results of various kinds of events occurring at random points of time. We always assume that each event only affects one of the processes. Between these events the states of the processes are considered to be constant. In the present paper we use discrete event simulation in order to analyze a multistate network flow system of repairable components. In order to study how the different components contribute to the system, it is necessary to describe the often complicated interaction between component processes and processes at the system level. While analytical considerations may throw some light on this, a simulation study often allows the analyst to explore more details. By producing stable curve estimates for the development of the various processes, one gets a much better insight in how such systems develop over time. These methods are particulary useful in the study of advanced importancez measures of repairable components. Such measures can be very complicated, and thus impossible to calculate analytically. By using discrete event simulations, however, this can be done in a very natural and intuitive way. In particular significant differences between the Barlow–Proschan measure and the Natvig measure in multistate network flow systems can be explored

  19. Dynamic combinatorial libraries: from exploring molecular recognition to systems chemistry.

    Science.gov (United States)

    Li, Jianwei; Nowak, Piotr; Otto, Sijbren

    2013-06-26

    Dynamic combinatorial chemistry (DCC) is a subset of combinatorial chemistry where the library members interconvert continuously by exchanging building blocks with each other. Dynamic combinatorial libraries (DCLs) are powerful tools for discovering the unexpected and have given rise to many fascinating molecules, ranging from interlocked structures to self-replicators. Furthermore, dynamic combinatorial molecular networks can produce emergent properties at systems level, which provide exciting new opportunities in systems chemistry. In this perspective we will highlight some new methodologies in this field and analyze selected examples of DCLs that are under thermodynamic control, leading to synthetic receptors, catalytic systems, and complex self-assembled supramolecular architectures. Also reviewed are extensions of the principles of DCC to systems that are not at equilibrium and may therefore harbor richer functional behavior. Examples include self-replication and molecular machines.

  20. Multiobjective optimization of availability and cost in repairable systems design via genetic algorithms and discrete event simulation

    Directory of Open Access Journals (Sweden)

    Isis Didier Lins

    2009-04-01

    Full Text Available This paper attempts to provide a more realistic approach to the characterization of system reliability when handling redundancy allocation problems: it considers repairable series-parallel systems comprised of components subjected to corrective maintenance actions with failure-repair cycles modeled by renewal processes. A multiobjective optimization approach is applied since increasing the number of redundancies not only enlarges system reliability but also its associated costs. Then a multiobjective genetic algorithm is coupled with discrete event simulation and its solutions present the compromise between system reliability and cost. Two examples are provided. In the first one, the proposed algorithm is validated by comparison with results obtained from a system devised as to allow for analytical solutions of the objective functions. The second case analyzes a repairable system subjected to perfect repairs. Results from both examples show that the proposed method can be a valuable tool for the decision maker when choosing the system design.Esse artigo utiliza uma abordagem mais realista para a caracterização da confiabilidade de sistemas em problemas de alocação de redundâncias: são considerados sistemas série-paralelo formados por componentes sujeitos a ações de manutenção corretiva com ciclos de falha-reparo modelados por processos de renovação. É aplicada uma abordagem de otimização multiobjetivo, pois o aumento de redundâncias eleva a confiabilidade do sistema e também os seus custos. Assim, um algoritmo genético multiobjetivo é integrado com simulação discreta de eventos e suas soluções apresentam o compromisso entre confiabilidade e custo do sistema. Dois exemplos são fornecidos. No primeiro, o algoritmo proposto é validado através da comparação com resultados obtidos de um sistema criado de forma a permitir soluções analíticas das funções-objetivo. No segundo, analisa-se um sistema reparável sujeito a

  1. Molecular biophysics: detection and characterization of damage in molecular, cellular, and physiological systems

    International Nuclear Information System (INIS)

    Danyluk, S.S.

    1979-01-01

    This section contains summaries of research on the detection and characterization of damage in molecular, cellular, and physiological systems. Projects under investigation in this section include: chemical synthesis of nucleic acid derivatives; structural and conformational properties of biological molecules in solution; crystallographic and chemical studies of immunoglobulin structure; instrument design and development for x-ray and neutron scattering studies of biological molecules; and chromobiology and circadian regulation

  2. Atomic and Molecular Systems in Intense Ultrashort Laser Pulses

    Science.gov (United States)

    Saenz, A.

    2008-07-01

    The full quantum mechanical treatment of atomic and molecular systems exposed to intense laser pulses is a so far unsolved challenge, even for systems as small as molecular hydrogen. Therefore, a number of simplified qualitative and quantitative models have been introduced in order to provide at least some interpretational tools for experimental data. The assessment of these models describing the molecular response is complicated, since a comparison to experiment requires often a number of averages to be performed. This includes in many cases averaging of different orientations of the molecule with respect to the laser field, focal volume effects, etc. Furthermore, the pulse shape and even the peak intensity is experimentally not known with very high precision; considering, e.g., the exponential intensity dependence of the ionization signal. Finally, experiments usually provide only relative yields. As a consequence of all these averagings and uncertainties, it is possible that different models may successfully explain some experimental results or features, although these models disagree substantially, if their predictions are compared before averaging. Therefore, fully quantum-mechanical approaches at least for small atomic and molecular systems are highly desirable and have been developed in our group. This includes efficient codes for solving the time-dependent Schrodinger equation of atomic hydrogen, helium or other effective one- or two-electron atoms as well as for the electronic motion in linear (effective) one-and two-electron diatomic molecules like H_2.Very recently, a code for larger molecular systems that adopts the so-called single-active electron approximation was also successfully implemented and applied. In the first part of this talk popular models describing intense laser-field ionization of atoms and their extensions to molecules are described. Then their validity is discussed on the basis of quantum-mechanical calculations. Finally, some

  3. Clinical Outcomes and Complications of Percutaneous Achilles Repair System Versus Open Technique for Acute Achilles Tendon Ruptures.

    Science.gov (United States)

    Hsu, Andrew R; Jones, Carroll P; Cohen, Bruce E; Davis, W Hodges; Ellington, J Kent; Anderson, Robert B

    2015-11-01

    Limited incision techniques for acute Achilles tendon ruptures have been developed in recent years to improve recovery and reduce postoperative complications compared with traditional open repair. The purpose of this retrospective cohort study was to analyze the clinical outcomes and postoperative complications between acute Achilles tendon ruptures treated using a percutaneous Achilles repair system (PARS [Arthrex, Inc, Naples, FL]) versus open repair and evaluate the overall outcomes for operatively treated Achilles ruptures. Between 2005 and 2014, 270 consecutive cases of operatively treated acute Achilles tendon ruptures were reviewed (101 PARS, 169 open). Patients with Achilles tendinopathy, insertional ruptures, chronic tears, or less than 3-month follow-up were excluded. Operative treatment consisted of a percutaneous technique (PARS) using a 2-cm transverse incision with FiberWire (Arthrex, Inc, Naples, FL) sutures or open repair using a 5- to 8-cm posteromedial incision with FiberWire in a Krackow fashion reinforced with absorbable sutures. Patient demographics were recorded along with medical comorbidities, activity at injury, time from injury to surgery, length of follow-up, return to baseline activities by 5 months, and postoperative complications. The most common activity during injury for both groups was basketball (PARS: 39%, open: 47%). A greater number of patients treated with PARS were able to return to baseline physical activities by 5 months compared with the open group (PARS: 98%, open: 82%; P = .0001). There were no significant differences (P > .05) between groups in rates of rerupture (P = 1.0), sural neuritis (P = .16), wound dehiscence (P = .74), superficial (P = .29) and/or deep infection (P = .29), or reoperation (P = .13). There were no deep vein thromboses (DVTs) or reruptures in either group. In the PARS group, there were no cases of sural neuritis, 3 cases (3%) of superficial wound dehiscence, and 2 reoperations (2%) for superficial

  4. Hybrid Metaheuristic Approach for Nonlocal Optimization of Molecular Systems.

    Science.gov (United States)

    Dresselhaus, Thomas; Yang, Jack; Kumbhar, Sadhana; Waller, Mark P

    2013-04-09

    Accurate modeling of molecular systems requires a good knowledge of the structure; therefore, conformation searching/optimization is a routine necessity in computational chemistry. Here we present a hybrid metaheuristic optimization (HMO) algorithm, which combines ant colony optimization (ACO) and particle swarm optimization (PSO) for the optimization of molecular systems. The HMO implementation meta-optimizes the parameters of the ACO algorithm on-the-fly by the coupled PSO algorithm. The ACO parameters were optimized on a set of small difluorinated polyenes where the parameters exhibited small variance as the size of the molecule increased. The HMO algorithm was validated by searching for the closed form of around 100 molecular balances. Compared to the gradient-based optimized molecular balance structures, the HMO algorithm was able to find low-energy conformations with a 87% success rate. Finally, the computational effort for generating low-energy conformation(s) for the phenylalanyl-glycyl-glycine tripeptide was approximately 60 CPU hours with the ACO algorithm, in comparison to 4 CPU years required for an exhaustive brute-force calculation.

  5. Molecular constituents of the extracellular matrix in rat liver mounting a hepatic progenitor cell response for tissue repair

    DEFF Research Database (Denmark)

    Vestentoft, Peter Siig; Jelnes, Peter; Andersen, Jesper Bøje

    2013-01-01

    differentially up- or down-modulated (P tier of defense (Agrn, Bgn, Fbn1, Col4a1, Col8a1, Col9a3, Lama5, Lamb1, Lamb2, Itga4, Igtb2, Itgb4, Itgb6, Nid2), and their signal intensities showed a strong or very...... strong correlation with Krt1- 19, a well-established marker of a ductular/HPC reaction. Furthermore, a significant up-modulation and very strong correlation between the transcriptional profiles of Krt1-19 and St14 encoding matriptase, a component of a novel protease system, was found in the second tier...... that laminin, Collagen1a1, agrin and nidogen1 surrounded bile ducts, proliferating cholangiocytes, and HPCs in ductular reactions regardless of the nature of defense. Similarly, matriptase and HAI-1 were expressed in cholangiocytes regardless of the tier of defense, but in the second tier of defense...

  6. Molecular mechanisms of aging and immune system regulation in Drosophila.

    Science.gov (United States)

    Eleftherianos, Ioannis; Castillo, Julio Cesar

    2012-01-01

    Aging is a complex process that involves the accumulation of deleterious changes resulting in overall decline in several vital functions, leading to the progressive deterioration in physiological condition of the organism and eventually causing disease and death. The immune system is the most important host-defense mechanism in humans and is also highly conserved in insects. Extensive research in vertebrates has concluded that aging of the immune function results in increased susceptibility to infectious disease and chronic inflammation. Over the years, interest has grown in studying the molecular interaction between aging and the immune response to pathogenic infections. The fruit fly Drosophila melanogaster is an excellent model system for dissecting the genetic and genomic basis of important biological processes, such as aging and the innate immune system, and deciphering parallel mechanisms in vertebrate animals. Here, we review the recent advances in the identification of key players modulating the relationship between molecular aging networks and immune signal transduction pathways in the fly. Understanding the details of the molecular events involved in aging and immune system regulation will potentially lead to the development of strategies for decreasing the impact of age-related diseases, thus improving human health and life span.

  7. Selective excitation, relaxation, and energy channeling in molecular systems

    International Nuclear Information System (INIS)

    Rhodes, W.C.

    1993-08-01

    Research involves theoretical studies of response, relaxation, and correlated motion in time-dependent behavior of large molecular systems ranging from polyatomic molecules to protein molecules in their natural environment. Underlying theme is subsystem modulation dynamics. Main idea is that quantum mechanical correlations between components of a system develop with time, playing a major role in determining the balance between coherent and dissipative forces. Central theme is interplay of coherence and dissipation in determining the nature of dynamic structuring and energy flow in molecular transformation mechanisms. Subsystem equations of motion are being developed to show how nonlinear, dissipative dynamics of a particular subsystem arise from correlated interactions with the rest of the system (substituent groups, solvent, lattice modes, etc.); one consequence is resonance structures and networks. Quantum dynamics and thermodynamics are being applied to understand control and energy transfer mechanisms in biological functions of protein molecules; these mechanisms are both global and local. Besides the above theory, the research deals with phenomenological aspects of molecular systems

  8. Analysis of DNA vulnerability to damage, repair and degradation in tissues of irradiated animals

    International Nuclear Information System (INIS)

    Ryabchenko, N.I.; Ivannik, B.P.

    1982-01-01

    Single-strand and paired ruptures of DNA were found to result in appearance of locally denaturated areas in its secondary structure and to disordered protein-DNA interaction. It was shown with the use of the viscosimeter method of measuring the molecular mass of single stranded high-polymeric DNA that cells of various tissues by the intensity of DNA repair can be divided into two groups, rapid- and slow-repair ones. Tissue specificity of enzyme function of the repair systems and systems responsible for post-irradiation DNA degradation depends on the activity of endonucleases synthesized by the cells both in health and in their irradiation-induced synthesis

  9. Molecular cloning and characterization of a Streptococcus sanguis DNase necessary for repair of DNA damage induced by UV light and methyl methanesulfonate

    International Nuclear Information System (INIS)

    Lindler, L.E.; Macrina, F.L.

    1987-01-01

    We developed a method for cloning cellular nucleases from streptococci. Recombinant lambda gt11 bacteriophage containing streptococcal nuclease determinants were identified by the production of pink plaques on toluidine blue O DNase plates. We used this technique to clone a 3.2-kilobase-pair EcoRI fragment with DNase activity from the chromosome of Streptococcus sanguis. The locus was designated don (DNase one) and could be subcloned and stably maintained on plasmid vectors in Escherichia coli. Minicell analyses of various subclones of the don locus allowed us to determine the coding region and size of the Don nuclease in E. coli. The don gene product had an apparent molecular mass of 34 kilodaltons and degraded native DNA most efficiently, with lesser activity against denatured DNA and no detectable activity against RNA. S. sanguis don deletion mutants were constructed by transformation of competent cells with in vitro-prepared plasmid constructs. S. sanguis don deletion mutants retained normal transformation frequencies for exogenously added donor DNA. However, when compared with Don+ wild-type cells, these mutants were hypersensitive to DNA damage induced by UV light and methyl methanesulfonate. An S. sanguis don-specific DNA probe detected homology to chromosomal DNA isolated from Streptococcus pneumoniae and Streptococcus mutans Bratthall serogroups d and g. Our results suggested that the don locus was the S. sanguis allele of the previously described S. pneumoniae major exonuclease and was involved in repair of DNA damage. Furthermore, hybridization studies suggested that the don locus was conserved among species of oral streptococci

  10. Application of Rapid Prototyping Technique and Intraoperative Navigation System for the Repair and Reconstruction of Orbital Wall Fractures

    Science.gov (United States)

    Cha, Jong Hyun; Lee, Yong Hae; Ruy, Wan Chul; Roe, Young; Moon, Myung Ho

    2016-01-01

    Background Restoring the orbital cavity in large blow out fractures is a challenge for surgeons due to the anatomical complexity. This study evaluated the clinical outcomes and orbital volume after orbital wall fracture repair using a rapid prototyping (RP) technique and intraoperative navigation system. Methods This prospective study was conducted on the medical records and radiology records of 12 patients who had undergone a unilateral blow out fracture reconstruction using a RP technique and an intraoperative navigation system from November 2014 to March 2015. The surgical results were assessed by an ophthalmic examination and a comparison of the preoperative and postoperative orbital volume ratio (OVR) values. Results All patients had a successful treatment outcome without complications. Volumetric analysis revealed a significant decrease in the mean OVR from 1.0952±0.0662 (ranging from 0.9917 to 1.2509) preoperatively to 0.9942±0.0427 (ranging from 0.9394 to 1.0680) postoperatively. Conclusion The application of a RP technique for the repair of orbital wall fractures is a useful tool that may help improve the clinical outcomes by understanding the individual anatomy, determining the operability, and restoring the orbital cavity volume through optimal implant positioning along with an intraoperative navigation system. PMID:28913272

  11. Assembly, destruction and manipulation of atomic, molecular and complex systems

    International Nuclear Information System (INIS)

    Le Padellec, Arnaud Pierre Frederic

    2003-04-01

    In this report for Accreditation to Supervise Researches (HDR), the author first indicates his professional curriculum (diplomas, teaching activities, responsibilities in the field of education and research, publications), and then proposes a presentation of his scientific works and researches. He notably proposes an overview of the different experimental techniques he implemented: CRYRING storage ring, confluent beams, flow post-discharge with mass spectrometry and Langmuir probe, crossed beams, and so on. He reports works dealing with the manipulation and destruction of atomic, molecular and complex systems: detachment of atomic anions by electronic impact, detachment and dissociation of small carbon aggregates by electronic impact, dissociative recombination, dissociative ionisation and excitation, creation of pairs of ions, manipulation of sodium fluoride aggregates. He finally presents research projects regarding the assembly of molecular and complex systems

  12. Interactive display of molecular models using a microcomputer system

    Science.gov (United States)

    Egan, J. T.; Macelroy, R. D.

    1980-01-01

    A simple, microcomputer-based, interactive graphics display system has been developed for the presentation of perspective views of wire frame molecular models. The display system is based on a TERAK 8510a graphics computer system with a display unit consisting of microprocessor, television display and keyboard subsystems. The operating system includes a screen editor, file manager, PASCAL and BASIC compilers and command options for linking and executing programs. The graphics program, written in USCD PASCAL, involves the centering of the coordinate system, the transformation of centered model coordinates into homogeneous coordinates, the construction of a viewing transformation matrix to operate on the coordinates, clipping invisible points, perspective transformation and scaling to screen coordinates; commands available include ZOOM, ROTATE, RESET, and CHANGEVIEW. Data file structure was chosen to minimize the amount of disk storage space. Despite the inherent slowness of the system, its low cost and flexibility suggests general applicability.

  13. Catecholaminergic systems in stress: structural and molecular genetic approaches.

    Science.gov (United States)

    Kvetnansky, Richard; Sabban, Esther L; Palkovits, Miklos

    2009-04-01

    Stressful stimuli evoke complex endocrine, autonomic, and behavioral responses that are extremely variable and specific depending on the type and nature of the stressors. We first provide a short overview of physiology, biochemistry, and molecular genetics of sympatho-adrenomedullary, sympatho-neural, and brain catecholaminergic systems. Important processes of catecholamine biosynthesis, storage, release, secretion, uptake, reuptake, degradation, and transporters in acutely or chronically stressed organisms are described. We emphasize the structural variability of catecholamine systems and the molecular genetics of enzymes involved in biosynthesis and degradation of catecholamines and transporters. Characterization of enzyme gene promoters, transcriptional and posttranscriptional mechanisms, transcription factors, gene expression and protein translation, as well as different phases of stress-activated transcription and quantitative determination of mRNA levels in stressed organisms are discussed. Data from catecholamine enzyme gene knockout mice are shown. Interaction of catecholaminergic systems with other neurotransmitter and hormonal systems are discussed. We describe the effects of homotypic and heterotypic stressors, adaptation and maladaptation of the organism, and the specificity of stressors (physical, emotional, metabolic, etc.) on activation of catecholaminergic systems at all levels from plasma catecholamines to gene expression of catecholamine enzymes. We also discuss cross-adaptation and the effect of novel heterotypic stressors on organisms adapted to long-term monotypic stressors. The extra-adrenal nonneuronal adrenergic system is described. Stress-related central neuronal regulatory circuits and central organization of responses to various stressors are presented with selected examples of regulatory molecular mechanisms. Data summarized here indicate that catecholaminergic systems are activated in different ways following exposure to distinct

  14. Meningocele repair

    Science.gov (United States)

    ... is surgery to repair birth defects of the spine and spinal membranes. Meningocele and myelomeningocele ... is covered by a sterile dressing. Your child may then be transferred to a neonatal intensive ...

  15. Incorrect modeling of the failure process of minimally repaired systems under random conditions: The effect on the maintenance costs

    International Nuclear Information System (INIS)

    Pulcini, Gianpaolo

    2015-01-01

    This note investigates the effect of the incorrect modeling of the failure process of minimally repaired systems that operates under random environmental conditions on the costs of a periodic replacement maintenance. The motivation of this paper is given by a recently published paper, where a wrong formulation of the expected cost for unit time under a periodic replacement policy is obtained. This wrong formulation is due to the incorrect assumption that the intensity function of minimally repaired systems that operate under random conditions has the same functional form as the failure rate of the first failure time. This produced an incorrect optimization of the replacement maintenance. Thus, in this note the conceptual differences between the intensity function and the failure rate of the first failure time are first highlighted. Then, the correct expressions of the expected cost and of the optimal replacement period are provided. Finally, a real application is used to measure how severe can be the economical consequences caused by the incorrect modeling of the failure process.

  16. Endovascular repair of arterial iliac vessel wall lesions with a self-expandable nitinol stent graft system.

    Directory of Open Access Journals (Sweden)

    Birger Mensel

    Full Text Available To assess the therapeutic outcome after endovascular repair of iliac arterial lesions (IALs using a self-expandable Nitinol stent graft system.Between July 2006 and March 2013, 16 patients (13 males, mean age: 68 years with a self-expandable Nitinol stent graft. A total of 19 lesions were treated: nine true aneurysms, two anastomotic aneurysms, two dissections, one arteriovenous fistula, two type 1B endoleaks after endovascular aneurysm repair, one pseudoaneurysm, and two perforations after angioplasty. Pre-, intra-, and postinterventional imaging studies and the medical records were analyzed for technical and clinical success and postinterventional complications.The primary technical and clinical success rate was 81.3% (13/16 patients and 75.0% (12/16, respectively. Two patients had technical failure due to persistent type 1A endoleak and another patient due to acute stent graft thrombosis. One patient showed severe stent graft kinking on the first postinterventional day. In two patients, a second intervention was performed. The secondary technical and clinical success rate was 87.5% (14/16 and 93.8% (15/16. The minor complication rate was 6.3% (patient with painful hematoma at the access site. The major complication rate was 6.3% (patient with ipsilateral deep vein thrombosis. During median follow-up of 22.4 months, an infection of the aneurysm sac in one patient and a stent graft thrombosis in another patient were observed.Endovascular repair of various IALs with a self-expandable Nitinol stent graft is safe and effective.

  17. Relationship of DNA lesions and their repair to chromosomal aberration production

    International Nuclear Information System (INIS)

    Bender, M.A.

    1979-01-01

    Recent work on the roles of specific kinds of DNA lesions and their enzymatic repair systems in the production of chromosomal aberrations seems consistent with a simple molecular model of chromosomal aberrations formation. Evidence from experiments with the human repair-deficient genetic diseases xeroderma pigmentosom, ataxia telangiectasia, and Fanconi's anemia is reviewed in the light of the contributions to aberration production of single and double polynucleotide strand breaks, base damage, polynucleotide strand crosslinks, and pyrimidine cyclobutane dimers

  18. Relationship of DNA lesions and their repair to chromosomal aberration production

    Energy Technology Data Exchange (ETDEWEB)

    Bender, M.A.

    1979-01-01

    Recent work on the roles of specific kinds of DNA lesions and their enzymatic repair systems in the production of chromosomal aberrations seems consistent with a simple molecular model of chromosomal aberrations formation. Evidence from experiments with the human repair-deficient genetic diseases xeroderma pigmentosom, ataxia telangiectasia, and Fanconi's anemia is reviewed in the light of the contributions to aberration production of single and double polynucleotide strand breaks, base damage, polynucleotide strand crosslinks, and pyrimidine cyclobutane dimers.

  19. Review and application of group theory to molecular systems biology.

    Science.gov (United States)

    Rietman, Edward A; Karp, Robert L; Tuszynski, Jack A

    2011-06-22

    In this paper we provide a review of selected mathematical ideas that can help us better understand the boundary between living and non-living systems. We focus on group theory and abstract algebra applied to molecular systems biology. Throughout this paper we briefly describe possible open problems. In connection with the genetic code we propose that it may be possible to use perturbation theory to explore the adjacent possibilities in the 64-dimensional space-time manifold of the evolving genome. With regards to algebraic graph theory, there are several minor open problems we discuss. In relation to network dynamics and groupoid formalism we suggest that the network graph might not be the main focus for understanding the phenotype but rather the phase space of the network dynamics. We show a simple case of a C6 network and its phase space network. We envision that the molecular network of a cell is actually a complex network of hypercycles and feedback circuits that could be better represented in a higher-dimensional space. We conjecture that targeting nodes in the molecular network that have key roles in the phase space, as revealed by analysis of the automorphism decomposition, might be a better way to drug discovery and treatment of cancer.

  20. Olfactory memory formation in Drosophila: from molecular to systems neuroscience.

    Science.gov (United States)

    Davis, Ronald L

    2005-01-01

    The olfactory nervous system of insects and mammals exhibits many similarities, which suggests that the mechanisms for olfactory learning may be shared. Molecular genetic investigations of Drosophila learning have uncovered numerous genes whose gene products are essential for olfactory memory formation. Recent studies of the products of these genes have continued to expand the range of molecular processes known to underlie memory formation. Recent research has also broadened the neuroanatomical areas thought to mediate olfactory learning to include the antennal lobes in addition to a previously accepted and central role for the mushroom bodies. The roles for neurons extrinsic to the mushroom body neurons are becoming better defined. Finally, the genes identified to participate in Drosophila olfactory learning have conserved roles in mammalian organisms, highlighting the value of Drosophila for gene discovery.

  1. Nucleocytoplasmic Transport: A Paradigm for Molecular Logistics in Artificial Systems.

    Science.gov (United States)

    Vujica, Suncica; Zelmer, Christina; Panatala, Radhakrishnan; Lim, Roderick Y H

    2016-01-01

    Artificial organelles, molecular factories and nanoreactors are membrane-bound systems envisaged to exhibit cell-like functionality. These constitute liposomes, polymersomes or hybrid lipo-polymersomes that display different membrane-spanning channels and/or enclose molecular modules. To achieve more complex functionality, an artificial organelle should ideally sustain a continuous influx of essential macromolecular modules (i.e. cargoes) and metabolites against an outflow of reaction products. This would benefit from the incorporation of selective nanopores as well as specific trafficking factors that facilitate cargo selectivity, translocation efficiency, and directionality. Towards this goal, we describe how proteinaceous cargoes are transported between the nucleus and cytoplasm by nuclear pore complexes and the biological trafficking machinery in living cells (i.e. nucleocytoplasmic transport). On this basis, we discuss how biomimetic control may be implemented to selectively import, compartmentalize and accumulate diverse macromolecular modules against concentration gradients in artificial organelles.

  2. Clamp wins pipe repair prize

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    2001-04-01

    This paper describes the permanent pipeline repair system, developed by Tekmar, which is powered by seawater hydraulics and is easily installed and tested by any workclass remotely operated vehicle (rov). Details are given of the two main components of the system, namely, the diverless high pressure split repair clamp and the rov-operated tool to install it.

  3. Modulation of the DNA repair system and ATR-p53 mediated apoptosis is relevant for tributyltin-induced genotoxic effects in human hepatoma G2 cells.

    Science.gov (United States)

    Li, Bowen; Sun, Lingbin; Cai, Jiali; Wang, Chonggang; Wang, Mengmeng; Qiu, Huiling; Zuo, Zhenghong

    2015-01-01

    The toxic effects of tributyltin (TBT) have been extensively documented in several types of cells, but the molecular mechanisms related to the genotoxic effects of TBT have still not been fully elucidated. Our study showed that exposure of human hepatoma G2 cells to 1-4 μmol/L TBT for 3 hr caused severe DNA damage in a concentration-dependent manner. Moreover, the expression levels of key DNA damage sensor genes such as the replication factor C, proliferating cell nuclear antigen and poly (ADP-ribose) polymerase-1 were inhabited in a concentration-dependent manner. We further demonstrated that TBT induced cell apoptosis via the p53-mediated pathway, which was most likely activated by the ataxia telangiectasia mutated and rad-3 related (ATR) protein kinase. The results also showed that cytochrome c, caspase-3, caspase-8, caspase-9, and the B-cell lymphoma 2 were involved in this process. Taken together, we demonstrated for the first time that the inhibition of the DNA repair system might be more responsible for TBT-induced genotoxic effects in cells. Then the generated DNA damage induced by TBT initiated ATR-p53-mediated apoptosis. Copyright © 2014. Published by Elsevier B.V.

  4. DNA repair

    International Nuclear Information System (INIS)

    Van Zeeland, A.A.

    1984-01-01

    In this chapter a series of DNA repair pathways are discussed which are available to the cell to cope with the problem of DNA damaged by chemical or physical agents. In the case of microorganisms our knowledge about the precise mechanism of each DNA repair pathway and the regulation of it has been improved considerably when mutants deficient in these repair mechanisms became available. In the case of mammalian cells in culture, until recently there were very little repair deficient mutants available, because in almost all mammalian cells in culture at least the diploid number of chromosomes is present. Therefore the frequency of repair deficient mutants in such populations is very low. Nevertheless because replica plating techniques are improving some mutants from Chinese hamsters ovary cells and L5178Y mouse lymphoma cells are now available. In the case of human cells, cultures obtained from patients with certain genetic diseases are available. A number of cells appear to be sensitive to some chemical or physical mutagens. These include cells from patients suffering from xeroderma pigmentosum, Ataxia telangiectasia, Fanconi's anemia, Cockayne's syndrome. However, only in the case of xeroderma pigmentosum cells, has the sensitivity to ultraviolet light been clearly correlated with a deficiency in excision repair of pyrimidine dimers. Furthermore the work with strains obtained from biopsies from man is difficult because these cells generally have low cloning efficiencies and also have a limited lifespan in vitro. It is therefore very important that more repair deficient mutants will become available from established cell lines from human or animal origin

  5. Method and apparatus for in-system redundant array repair on integrated circuits

    Science.gov (United States)

    Bright, Arthur A.; Crumley, Paul G.; Dombrowa, Marc B.; Douskey, Steven M.; Haring, Rudolf A.; Oakland, Steven F.; Ouellette, Michael R.; Strissel, Scott A.

    2007-12-18

    Disclosed is a method of repairing an integrated circuit of the type comprising of a multitude of memory arrays and a fuse box holding control data for controlling redundancy logic of the arrays. The method comprises the steps of providing the integrated circuit with a control data selector for passing the control data from the fuse box to the memory arrays; providing a source of alternate control data, external of the integrated circuit; and connecting the source of alternate control data to the control data selector. The method comprises the further step of, at a given time, passing the alternate control data from the source thereof, through the control data selector and to the memory arrays to control the redundancy logic of the memory arrays.

  6. Design structure for in-system redundant array repair in integrated circuits

    Science.gov (United States)

    Bright, Arthur A.; Crumley, Paul G.; Dombrowa, Marc; Douskey, Steven M.; Haring, Rudolf A.; Oakland, Steven F.; Quellette, Michael R.; Strissel, Scott A.

    2008-11-25

    A design structure for repairing an integrated circuit during operation of the integrated circuit. The integrated circuit comprising of a multitude of memory arrays and a fuse box holding control data for controlling redundancy logic of the arrays. The design structure provides the integrated circuit with a control data selector for passing the control data from the fuse box to the memory arrays; providing a source of alternate control data, external of the integrated circuit; and connecting the source of alternate control data to the control data selector. The design structure further passes the alternate control data from the source thereof, through the control data selector and to the memory arrays to control the redundancy logic of the memory arrays.

  7. Method and apparatus for in-system redundant array repair on integrated circuits

    Science.gov (United States)

    Bright, Arthur A [Croton-on-Hudson, NY; Crumley, Paul G [Yorktown Heights, NY; Dombrowa, Marc B [Bronx, NY; Douskey, Steven M [Rochester, MN; Haring, Rudolf A [Cortlandt Manor, NY; Oakland, Steven F [Colchester, VT; Ouellette, Michael R [Westford, VT; Strissel, Scott A [Byron, MN

    2008-07-29

    Disclosed is a method of repairing an integrated circuit of the type comprising of a multitude of memory arrays and a fuse box holding control data for controlling redundancy logic of the arrays. The method comprises the steps of providing the integrated circuit with a control data selector for passing the control data from the fuse box to the memory arrays; providing a source of alternate control data, external of the integrated circuit; and connecting the source of alternate control data to the control data selector. The method comprises the further step of, at a given time, passing the alternate control data from the source thereof, through the control data selector and to the memory arrays to control the redundancy logic of the memory arrays.

  8. [Direct repair of adolescent lumbar spondylolysis using a pedicle screw-laminar hook system by paramedian approach].

    Science.gov (United States)

    Wang, Bin; Tang, Yong-hua; Tang, Hong-chao; Jin, Cai-yi

    2011-08-01

    To discuss the indication and clinical effect of direct repair of adolescent lumbar spondylolysis by screw-laminar hook system. From August 2003 to December 2008, 28 patients (13 males and 15 females,ranging in age from 15 and 26 years, averaged 21.6 years) with lumbar spondylolysis were treated with isthmic bone grafting and internal fixation with a pedicle screw-laminar hook system. Three patients had spondylolysis at L3, L4; 5 patients had spondylolysis at L4, L5; 8 patients had spondylolysis at L4; and 12 patients had spondylolysis at L5. All the patients had low back pain and lasted over 6 months. According to preoperative and postoperative plain radiograph, CT scan and Macnab criteria, the fusion rate and clinical effect of this technique were evaluated. All the patients were followed up with a mean period of 14.9 months, ranging from 9 to 24 months. All the patients had bony union according to the X-rays and CT scan. According to the calculation results of Macnab criteria, 22 patients got an excellent result, 5 good and 1 fair. The direct repair of adolescent lumbar spondylolysis with pedicle screw-laminar hook system can shorten length of operation,decrease blood loss, preserve more posterior structures of spine and avoid iatrogenic instability of spine. The postoperative immediate stability of vertebral segment is acquired and the mobility of adjacent intervertebral discs is reserved. The screw-laminar hook system for the treatment of adolescent spondylolisthesis can get satisfactory clinical results.

  9. DNA repair and cancer

    International Nuclear Information System (INIS)

    Rathore, Shakuntla; Joshi, Pankaj Kumar; Gaur, Sudha

    2012-01-01

    DNA repair refers to a collection of processes by which a cell identifies and corrects damage to the DNA molecule that encode it's genome. In human cells, both normal metabolic activities and environmental factors such as UV light and radiation can cause DNA damage, resulting in as many one million individual molecular lesions per day. Many of these lesions cause structural damage to the DNA molecule and can alter or eliminate the cell's ability to transcribe the gene that the affected DNA encodes. Other lesions include potentially harmful mutation in cell's genome which affect the survival of it's daughter cells after it undergoes mitosis. As a consequence, the DNA repair process is constantly active as it responds to damage in the DNA structure. Inherited mutation that affect DNA repair genes are strongly associated with high cancer risks in humans. Hereditary non polyposis colorectal cancer (HNPCC) is strongly associated with specific mutation in the DNA mismatch repair pathway. BRCA1, BRCA2 two famous mutation conferring a hugely increased risk of breast cancer on carrier, are both associated with a large number of DNA repair pathway, especially NHEJ and homologous recombination. Cancer therapy procedures such as chemotherapy and radiotherapy work by overwhelming the capacity of the cell to repair DNA damage, resulting in cell death. Cells that are most rapidly dividing most typically cancer cells are preferentially affected. The side effect is that other non-cancerous but rapidly dividing cells such as stem cells in the bone marrow are also affected. Modern cancer treatment attempt to localize the DNA damage to cells and tissue only associated with cancer, either by physical means (concentrating the therapeutic agent in the region of the tumor) or by biochemical means (exploiting a feature unique to cancer cells in the body). (author)

  10. International congress on DNA damage and repair: Book of abstracts

    Energy Technology Data Exchange (ETDEWEB)

    1987-01-01

    This document contains the abstracts of 105 papers presented at the Congress. Topics covered include the Escherichia coli nucleotide excision repair system, DNA repair in malignant transformations, defective DNA repair, and gene regulation. (TEM)

  11. International congress on DNA damage and repair: Book of abstracts

    International Nuclear Information System (INIS)

    1987-01-01

    This document contains the abstracts of 105 papers presented at the Congress. Topics covered include the Escherichia coli nucleotide excision repair system, DNA repair in malignant transformations, defective DNA repair, and gene regulation

  12. Repair capability of mammalian cell fractions demonstrated using infectivity of bacteriophage DNA

    International Nuclear Information System (INIS)

    Lai, S.P.; Lytle, C.D.; Benane, S.G.

    1976-01-01

    Extracts of Potoroo kidney cells (PtK2) were examined for ability to provide a repair function in vitro. The biological activity (infectivity) of uv-irradiated replicative form (RF) DNA of bacteriophage phiX174 was restored during incubation of the DNA with a nuclear extract but not with a cytoplasmic extract. The infectivity of the RF-DNA was determined in spheroplasts of E. coli C/sub s/, which is HCR - . This system for biological assay of uv-irradiated DNA repaired in vitro may be used to complement biochemical and biophysical investigations of molecular repair mechanisms in mammalian cells

  13. A new parallel molecular dynamics algorithm for organic systems

    International Nuclear Information System (INIS)

    Plimpton, S.; Hendrickson, B.; Heffelfinger, G.

    1993-01-01

    A new parallel algorithm for simulating bonded molecular systems such as polymers and proteins by molecular dynamics (MD) is presented. In contrast to methods that extract parallelism by breaking the spatial domain into sub-pieces, the new method does not require regular geometries or uniform particle densities to achieve high parallel efficiency. For very large, regular systems spatial methods are often the best choice, but in practice the new method is faster for systems with tens-of-thousands of atoms simulated on large numbers of processors. It is also several times faster than the techniques commonly used for parallelizing bonded MD that assign a subset of atoms to each processor and require all-to-all communication. Implementation of the algorithm in a CHARMm-like MD model with many body forces and constraint dynamics is discussed and timings on the Intel Delta and Paragon machines are given. Example calculations using the algorithm in simulations of polymers and liquid-crystal molecules will also be briefly discussed

  14. DNA barcode-based molecular identification system for fish species.

    Science.gov (United States)

    Kim, Sungmin; Eo, Hae-Seok; Koo, Hyeyoung; Choi, Jun-Kil; Kim, Won

    2010-12-01

    In this study, we applied DNA barcoding to identify species using short DNA sequence analysis. We examined the utility of DNA barcoding by identifying 53 Korean freshwater fish species, 233 other freshwater fish species, and 1339 saltwater fish species. We successfully developed a web-based molecular identification system for fish (MISF) using a profile hidden Markov model. MISF facilitates efficient and reliable species identification, overcoming the limitations of conventional taxonomic approaches. MISF is freely accessible at http://bioinfosys.snu.ac.kr:8080/MISF/misf.jsp .

  15. Protracted radiation-induced alterations in hematopoietic repair and recovery

    International Nuclear Information System (INIS)

    Seed, T.M.; Fritz, T.E.

    1997-01-01

    Pathologic predisposition of beagle dogs under chronic, low daily dose (7.5 cGy day -1 ) whole-body gamma irradiation has been studied relative to molecular repair and hematopoietic competency. Molecular repair, assessed by a microscopy-based unscheduled DNA synthesis (UDS) response, was measured within proliferative and nonproliferative marrow myeloid elements of dogs with markedly different hematopoietic capacities (low capacity, aplasia-prone [AA + ] versus high capacity, myeloproliferative disease-prone [MPD + ]) under protracted radiation stress. Results indicated that protracted exposure elicited a net increase in UDS-repair capacity that was largely independent of exposure duration. This enhanced capacity resulted from the increased strength of the UDS signal together with an expanded number of positively responding cells. The combined response was strong in primitive blasts and weak in more differentiated myelocytic cells. The UDS repair response of the MPD + dogs was significantly greater than that of the AA + animals and was clearly modified relative to the controls. These results suggest that both resiliency and pathologic potential of the hematopoietic system under protracted radiation stress is, in part, associated with an augmentable DNA repair within the more primitive myeloid marrow elements. (author)

  16. DCMS: A data analytics and management system for molecular simulation.

    Science.gov (United States)

    Kumar, Anand; Grupcev, Vladimir; Berrada, Meryem; Fogarty, Joseph C; Tu, Yi-Cheng; Zhu, Xingquan; Pandit, Sagar A; Xia, Yuni

    Molecular Simulation (MS) is a powerful tool for studying physical/chemical features of large systems and has seen applications in many scientific and engineering domains. During the simulation process, the experiments generate a very large number of atoms and intend to observe their spatial and temporal relationships for scientific analysis. The sheer data volumes and their intensive interactions impose significant challenges for data accessing, managing, and analysis. To date, existing MS software systems fall short on storage and handling of MS data, mainly because of the missing of a platform to support applications that involve intensive data access and analytical process. In this paper, we present the database-centric molecular simulation (DCMS) system our team developed in the past few years. The main idea behind DCMS is to store MS data in a relational database management system (DBMS) to take advantage of the declarative query interface ( i.e. , SQL), data access methods, query processing, and optimization mechanisms of modern DBMSs. A unique challenge is to handle the analytical queries that are often compute-intensive. For that, we developed novel indexing and query processing strategies (including algorithms running on modern co-processors) as integrated components of the DBMS. As a result, researchers can upload and analyze their data using efficient functions implemented inside the DBMS. Index structures are generated to store analysis results that may be interesting to other users, so that the results are readily available without duplicating the analysis. We have developed a prototype of DCMS based on the PostgreSQL system and experiments using real MS data and workload show that DCMS significantly outperforms existing MS software systems. We also used it as a platform to test other data management issues such as security and compression.

  17. Studies on the repair of damaged DNA in bacteriophage, bacterial and mammalian systems. Comprehensive report, 1 February 1981-15 September 1983

    International Nuclear Information System (INIS)

    Friedberg, E.C.

    1983-01-01

    We have explored the molecular mechanism of the repair of DNA at a number of different levels of biological organization, by investigating bacteriophage, bacterial, yeast and mammalian (including human) cells. We have demonstrated that uv endonuclease of phage T4 not only possesses pyrimidine dimer (PD)-DNA glycosylase activity but also apyrimidinic (AP) endonuclease activity. The demonstration of both activities provided an explanation for the specific endonucleosytic cleavage of DNA at sites of pyrimidine dimers catalyzed by this small protein. A new apurinic/apyrimidinic (AP) endonuclease, specific for sites of of base loss in single stranded DNA has been isolated from E. celi and presumably recognizes these lesions in single stranded regions of duplex DNA. We have partially purified this enzyme and have carried out a preliminary characterization of the activity. We treated xeroderma pigmentosum and normal cells with sodium butyrate in the hope of restoring normal levels of excision repair to the former. Although this result was not obtained, we established that all cells treated with sodium butyrate show enhanced levels of repair synthesis, thus providing a means for increasing the sensitivity of this commonly used technique for measuring DNA repair in mammalian cells in culture

  18. DNA repair: Dynamic defenders against cancer and aging

    Energy Technology Data Exchange (ETDEWEB)

    Fuss, Jill O.; Cooper, Priscilla K.

    2006-04-01

    You probably weren't thinking about your body's cellular DNA repair systems the last time you sat on the beach in the bright sunshine. Fortunately, however, while you were subjecting your DNA to the harmful effects of ultraviolet light, your cells were busy repairing the damage. The idea that our genetic material could be damaged by the sun was not appreciated in the early days of molecular biology. When Watson and Crick discovered the structure of DNA in 1953 [1], it was assumed that DNA is fundamentally stable since it carries the blueprint of life. However, over 50 years of research have revealed that our DNA is under constant assault by sunlight, oxygen, radiation, various chemicals, and even our own cellular processes. Cleverly, evolution has provided our cells with a diverse set of tools to repair the damage that Mother Nature causes. DNA repair processes restore the normal nucleotide sequence and DNA structure of the genome after damage [2]. These responses are highly varied and exquisitely regulated. DNA repair mechanisms are traditionally characterized by the type of damage repaired. A large variety of chemical modifications can alter normal DNA bases and either lead to mutations or block transcription if not repaired, and three distinct pathways exist to remove base damage. Base excision repair (BER) corrects DNA base alterations that do not distort the overall structure of the DNA helix such as bases damaged by oxidation resulting from normal cellular metabolism. While BER removes single damaged bases, nucleotide excision repair (NER) removes short segments of nucleotides (called oligonucleotides) containing damaged bases. NER responds to any alteration that distorts the DNA helix and is the mechanism responsible for repairing bulky base damage caused by carcinogenic chemicals such as benzo [a]pyrene (found in cigarette smoke and automobile exhaust) as well as covalent linkages between adjacent pyrimidine bases resulting from the ultraviolet

  19. Minimal access direct spondylolysis repair using a pedicle screw-rod system: a case series

    Directory of Open Access Journals (Sweden)

    Mohi Eldin Mohamed

    2012-11-01

    Full Text Available Abstract Introduction Symptomatic spondylolysis is always challenging to treat because the pars defect causing the instability needs to be stabilized while segmental fusion needs to be avoided. Direct repair of the pars defect is ideal in cases of spondylolysis in which posterior decompression is not necessary. We report clinical results using segmental pedicle-screw-rod fixation with bone grafting in patients with symptomatic spondylolysis, a modification of a technique first reported by Tokuhashi and Matsuzaki in 1996. We also describe the surgical technique, assess the fusion and analyze the outcomes of patients. Case presentation At Cairo University Hospital, eight out of twelve Egyptian patients’ acute pars fractures healed after conservative management. Of those, two young male patients underwent an operative procedure for chronic low back pain secondary to pars defect. Case one was a 25-year-old Egyptian man who presented with a one-year history of axial low back pain, not radiating to the lower limbs, after falling from height. Case two was a 29-year-old Egyptian man who presented with a one-year history of axial low back pain and a one-year history of mild claudication and infrequent radiation to the leg, never below the knee. Utilizing a standardized mini-access fluoroscopically-guided surgical protocol, fixation was established with two titanium pedicle screws place into both pedicles, at the same level as the pars defect, without violating the facet joint. The cleaned pars defect was grafted; a curved titanium rod was then passed under the base of the spinous process of the affected vertebra, bridging the loose fragment, and attached to the pedicle screw heads, to uplift the spinal process, followed by compression of the defect. The patients were discharged three days after the procedure, with successful fusion at one-year follow-up. No rod breakage or implant-related complications were reported. Conclusions Where there is no

  20. Some areas of reliability technique which have been neglected to some extent - maintainability - human reliability - mechanical reliability - repairable systems

    International Nuclear Information System (INIS)

    Akersten, P.A.

    1985-01-01

    The present thesis consists of four papers, three of which are of a expositary nature and one more theoretical. The first two papers have a natural coupling to the man-machine interface. The first paper is devoted to the concept of maintainability and the role of man as maintenance technician. The second paper discusses aspects of human reliability, mainly studying man as operator. However, maintenance tasks can be studied in the same manner. The third paper concerns reliability prediction for mechanical components. This is an area of vital importance for the reliability practitioner, who needs realistic and easy-to-use mathematical models for different failure modes. The fourth paper discusses mathematical models for repairable systems, especially the problem of testing whether a constant event intensity model is adequate or not. (author)

  1. Repair process and a repaired component

    Energy Technology Data Exchange (ETDEWEB)

    Roberts, III, Herbert Chidsey; Simpson, Stanley F.

    2018-02-20

    Matrix composite component repair processes are disclosed. The matrix composite repair process includes applying a repair material to a matrix composite component, securing the repair material to the matrix composite component with an external securing mechanism and curing the repair material to bond the repair material to the matrix composite component during the securing by the external securing mechanism. The matrix composite component is selected from the group consisting of a ceramic matrix composite, a polymer matrix composite, and a metal matrix composite. In another embodiment, the repair process includes applying a partially-cured repair material to a matrix composite component, and curing the repair material to bond the repair material to the matrix composite component, an external securing mechanism securing the repair material throughout a curing period, In another embodiment, the external securing mechanism is consumed or decomposed during the repair process.

  2. International Conference on Intelligent Systems for Molecular Biology (ISMB)

    Energy Technology Data Exchange (ETDEWEB)

    Goldberg, Debra; Hibbs, Matthew; Kall, Lukas; Komandurglayavilli, Ravikumar; Mahony, Shaun; Marinescu, Voichita; Mayrose, Itay; Minin, Vladimir; Neeman, Yossef; Nimrod, Guy; Novotny, Marian; Opiyo, Stephen; Portugaly, Elon; Sadka, Tali; Sakabe, Noboru; Sarkar, Indra; Schaub, Marc; Shafer, Paul; Shmygelska, Olena; Singer, Gregory; Song, Yun; Soumyaroop, Bhattacharya; Stadler, Michael; Strope, Pooja; Su, Rong; Tabach, Yuval; Tae, Hongseok; Taylor, Todd; Terribilini, Michael; Thomas, Asha; Tran, Nam; Tseng, Tsai-Tien; Vashist, Akshay; Vijaya, Parthiban; Wang, Kai; Wang, Ting; Wei, Lai; Woo, Yong; Wu, Chunlei; Yamanishi, Yoshihiro; Yan, Changhui; Yang, Jack; Yang, Mary; Ye, Ping; Zhang, Miao

    2009-12-29

    The Intelligent Systems for Molecular Biology (ISMB) conference has provided a general forum for disseminating the latest developments in bioinformatics on an annual basis for the past 13 years. ISMB is a multidisciplinary conference that brings together scientists from computer science, molecular biology, mathematics and statistics. The goal of the ISMB meeting is to bring together biologists and computational scientists in a focus on actual biological problems, i.e., not simply theoretical calculations. The combined focus on "intelligent systems" and actual biological data makes ISMB a unique and highly important meeting, and 13 years of experience in holding the conference has resulted in a consistently well organized, well attended, and highly respected annual conference. The ISMB 2005 meeting was held June 25-29, 2005 at the Renaissance Center in Detroit, Michigan. The meeting attracted over 1,730 attendees. The science presented was exceptional, and in the course of the five-day meeting, 56 scientific papers, 710 posters, 47 Oral Abstracts, 76 Software demonstrations, and 14 tutorials were presented. The attendees represented a broad spectrum of backgrounds with 7% from commercial companies, over 28% qualifying for student registration, and 41 countries were represented at the conference, emphasizing its important international aspect. The ISMB conference is especially important because the cultures of computer science and biology are so disparate. ISMB, as a full-scale technical conference with refereed proceedings that have been indexed by both MEDLINE and Current Contents since 1996, bridges this cultural gap.

  3. Diffusion-controlled interface kinetics-inclusive system-theoretic propagation models for molecular communication systems

    Science.gov (United States)

    Chude-Okonkwo, Uche A. K.; Malekian, Reza; Maharaj, B. T.

    2015-12-01

    Inspired by biological systems, molecular communication has been proposed as a new communication paradigm that uses biochemical signals to transfer information from one nano device to another over a short distance. The biochemical nature of the information transfer process implies that for molecular communication purposes, the development of molecular channel models should take into consideration diffusion phenomenon as well as the physical/biochemical kinetic possibilities of the process. The physical and biochemical kinetics arise at the interfaces between the diffusion channel and the transmitter/receiver units. These interfaces are herein termed molecular antennas. In this paper, we present the deterministic propagation model of the molecular communication between an immobilized nanotransmitter and nanoreceiver, where the emission and reception kinetics are taken into consideration. Specifically, we derived closed-form system-theoretic models and expressions for configurations that represent different communication systems based on the type of molecular antennas used. The antennas considered are the nanopores at the transmitter and the surface receptor proteins/enzymes at the receiver. The developed models are simulated to show the influence of parameters such as the receiver radius, surface receptor protein/enzyme concentration, and various reaction rate constants. Results show that the effective receiver surface area and the rate constants are important to the system's output performance. Assuming high rate of catalysis, the analysis of the frequency behavior of the developed propagation channels in the form of transfer functions shows significant difference introduce by the inclusion of the molecular antennas into the diffusion-only model. It is also shown that for t > > 0 and with the information molecules' concentration greater than the Michaelis-Menten kinetic constant of the systems, the inclusion of surface receptors proteins and enzymes in the models

  4. Repair of segmental bone defect using Totally Vitalized tissue engineered bone graft by a combined perfusion seeding and culture system.

    Directory of Open Access Journals (Sweden)

    Lin Wang

    Full Text Available BACKGROUND: The basic strategy to construct tissue engineered bone graft (TEBG is to combine osteoblastic cells with three dimensional (3D scaffold. Based on this strategy, we proposed the "Totally Vitalized TEBG" (TV-TEBG which was characterized by abundant and homogenously distributed cells with enhanced cell proliferation and differentiation and further investigated its biological performance in repairing segmental bone defect. METHODS: In this study, we constructed the TV-TEBG with the combination of customized flow perfusion seeding/culture system and β-tricalcium phosphate (β-TCP scaffold fabricated by Rapid Prototyping (RP technique. We systemically compared three kinds of TEBG constructed by perfusion seeding and perfusion culture (PSPC method, static seeding and perfusion culture (SSPC method, and static seeding and static culture (SSSC method for their in vitro performance and bone defect healing efficacy with a rabbit model. RESULTS: Our study has demonstrated that TEBG constructed by PSPC method exhibited better biological properties with higher daily D-glucose consumption, increased cell proliferation and differentiation, and better cell distribution, indicating the successful construction of TV-TEBG. After implanted into rabbit radius defects for 12 weeks, PSPC group exerted higher X-ray score close to autograft, much greater mechanical property evidenced by the biomechanical testing and significantly higher new bone formation as shown by histological analysis compared with the other two groups, and eventually obtained favorable healing efficacy of the segmental bone defect that was the closest to autograft transplantation. CONCLUSION: This study demonstrated the feasibility of TV-TEBG construction with combination of perfusion seeding, perfusion culture and RP technique which exerted excellent biological properties. The application of TV-TEBG may become a preferred candidate for segmental bone defect repair in orthopedic and

  5. DNA damage repair and radiosensitivity

    International Nuclear Information System (INIS)

    Suzuki, Norio

    2003-01-01

    Tailored treatment is not new in radiotherapy; it has been the major subject for the last 20-30 years. Radiation responses and RBE (relative biological effectiveness) depend on assay systems, endpoints, type of tissues and tumors, radiation quality, dose rate, dose fractionation, physiological and environmental factors etc, Latent times to develop damages also differ among tissues and endpoints depending on doses and radiation quality. Recent progress in clarification of radiation induced cell death, especially of apoptotic cell death, is quite important for understanding radiosensitivity of tumor cure process as well as of tumorigenesis. Apoptotic cell death as well as dormant cells had been unaccounted and missed into a part of reproductive cell death. Another area of major progress has been made in clarifying repair mechanisms of radiation damage, i.e., non-homologous end joining (NHEJ) and homologous recombinational repair (HRR). New approaches and developments such as cDNA or protein micro arrays and so called informatics in addition to basic molecular biological analysis are expected to aid identifying molecules and their roles in signal transduction pathways, which are multi-factorial and interactive each other being involved in radiation responses. (authors)

  6. Electronic structure, transport, and collective effects in molecular layered systems

    Directory of Open Access Journals (Sweden)

    Torsten Hahn

    2017-10-01

    Full Text Available The great potential of organic heterostructures for organic device applications is exemplified by the targeted engineering of the electronic properties of phthalocyanine-based systems. The transport properties of two different phthalocyanine systems, a pure copper phthalocyanine (CoPc and a flourinated copper phthalocyanine–manganese phthalocyanine (F16CoPc/MnPc heterostructure, are investigated by means of density functional theory (DFT and the non-equilibrium Green’s function (NEGF approach. Furthermore, a master-equation-based approach is used to include electronic correlations beyond the mean-field-type approximation of DFT. We describe the essential theoretical tools to obtain the parameters needed for the master equation from DFT results. Finally, an interacting molecular monolayer is considered within a master-equation approach.

  7. Stability of molecular dynamics simulations of classical systems

    DEFF Research Database (Denmark)

    Toxværd, Søren

    2012-01-01

    The existence of a shadow Hamiltonian for discrete classical dynamics, obtained by an asymptotic expansion for a discrete symplectic algorithm, is employed to determine the limit of stability for molecular dynamics (MD) simulations with respect to the time-increment h of the discrete dynamics....... The investigation is based on the stability of the shadow energy, obtained by including the first term in the asymptotic expansion, and on the exact solution of discrete dynamics for a single harmonic mode. The exact solution of discrete dynamics for a harmonic potential with frequency ω gives a criterion...... for the limit of stability h ⩽ 2/ω. Simulations of the Lennard-Jones system and the viscous Kob-Andersen system show that one can use the limit of stability of the shadow energy or the stability criterion for a harmonic mode on the spectrum of instantaneous frequencies to determine the limit of stability of MD...

  8. Intermolecular thermoelectric-like effects in molecular nano electronic systems

    International Nuclear Information System (INIS)

    Sabzyan, H.; Safari, R.

    2012-01-01

    Intramolecular thermoelectric-like coefficients are introduced and computed of a single molecule nano electronic system. Values of the electronic Intramolecular thermoelectric-like coefficients are calculated based on the density and energy transfers between different parts of the molecule using quantum theory of atoms in molecule. Since, Joule and Peltier heating are even (symmetrical) and odd (antisymmetric) functions of the external bias, it is possible to divide Intramolecular thermoelectric-like coefficients into two components, symmetrical and antisymmetrical Intramolecular thermoelectric-like coefficients, which describe the intramolecular Joule-like and Peltier-like effects, respectively. In addition, a semiclassical temperature model is presented to describe intramolecular temperature mapping (intramolecular energy distributions) in molecular nano electronic systems.

  9. Encounters of The Solar System With Molecular Clouds

    International Nuclear Information System (INIS)

    Wickramasinghe, J. T.

    2008-01-01

    The solar system has penetrated about 5 -- 10 giant molecular clouds over its history, and passes within 5 parsecs of a star-forming nebula every 100 million years or so. Numerical simulations of the effect of such encounters in perturbing the Oort cloud of comets are carried out using standard n-body computational techniques. It is found that the ingress of comets into the inner planetary system during such encounters amounts to factors of ∼100 over the average. During an encounter the impact rate of comets onto Earth increases by a comparable factor. The of ages of impact craters on the Earth is shown to be consistent with predictions from the model

  10. Systemic administration of high-molecular weight hyaluronan stimulates wound healing in genetically diabetic mice.

    Science.gov (United States)

    Galeano, Mariarosaria; Polito, Francesca; Bitto, Alessandra; Irrera, Natasha; Campo, Giuseppe M; Avenoso, Angela; Calò, Margherita; Lo Cascio, Patrizia; Minutoli, Letteria; Barone, Mauro; Squadrito, Francesco; Altavilla, Domenica

    2011-07-01

    Hyaluronic acid (HA), an essential component of the extracellular matrix, is an efficient space filler that maintains hydration, serves as a substrate for assembly of proteoglycans and is involved in wound healing. Although numerous pieces of evidence demonstrate beneficial effects in promoting wound healing in diabetes, a systemic approach has never been tested. We used an incisional wound healing model in genetically diabetic mice to test the effects of systemic injection of HA. Diabetic (n=56) and normoglycemic (n=56) mice were subjected to incision and randomized (8 groups of 7 animals each) to receive HA at different doses, 7.5, 15 and 30mg/kg/i.p., or vehicle (0.9% NaCl solution) for 12days. At the end of the experiment animals were sacrificed and skin wounds were excised for histological, biochemical and molecular analysis. Histology revealed that the most effective dose to improve wound repair and angiogenesis in diabetic mice was 30mg/kg. Furthermore HA injection (30mg/kg) improved the altered healing pattern in diabetic animals, increased skin remodeling proteins TGF-β and transglutaminase-II and restored the altered expression of cyclin B1/Cdc2 complex. Evaluation of skin from diabetic animals injected with HA revealed also an increase in HA content, suggesting that systemic injection may be able to restore the reduced intracellular HA pool of diabetic mice. Finally HA markedly improved skin mechanical properties. These promising results, if confirmed in a clinical setting, may improve the care and management of diabetic patients. Copyright © 2011 Elsevier B.V. All rights reserved.

  11. Turbine repair process, repaired coating, and repaired turbine component

    Science.gov (United States)

    Das, Rupak; Delvaux, John McConnell; Garcia-Crespo, Andres Jose

    2015-11-03

    A turbine repair process, a repaired coating, and a repaired turbine component are disclosed. The turbine repair process includes providing a turbine component having a higher-pressure region and a lower-pressure region, introducing particles into the higher-pressure region, and at least partially repairing an opening between the higher-pressure region and the lower-pressure region with at least one of the particles to form a repaired turbine component. The repaired coating includes a silicon material, a ceramic matrix composite material, and a repaired region having the silicon material deposited on and surrounded by the ceramic matrix composite material. The repaired turbine component a ceramic matrix composite layer and a repaired region having silicon material deposited on and surrounded by the ceramic matrix composite material.

  12. The role of the HCR system in the repair of lethal lesions of Bacillus subtilis phages and their transfecting DNA damaged by radiation and alkylating agents

    International Nuclear Information System (INIS)

    Vizdalova, M.; Janovska, E.; Zhestyanikov, V.D.

    1980-01-01

    The role of the HCR system in the repair of prelethal lesions induced by UV light, γ radiation and alkylating agents was studied in the Bacillus subtilis SPP1 phage, its heat sensitive mutants (N3, N73 nad ts 1 ) and corresponding infectious DNA. The survival of phages and their transfecting DNA after treatment with UV light is substantially higher in hcr + cells than in hcr cells, the differences being more striking in intact phages than in their transfecting DNA's. Repair inhibitors reduce survival in hcr + cells: caffeine lowers the survival of UV-irradiated phage SPP1 in exponentially growing hcr + cells but has no effect on its survival in competent hcr + cells; acriflavin and ethidium bromide decrease the survival of the UV-irradiated SPP1 phage in both exponentially growing and competent hcr + cells to the level of survival observed in hcr cells; moreover, ethidium bromide lowers the number of infective centres in hcr + cells of the UV-irradiated DNA of the SPP1 phage. Repair inhibitors do not lower the survival of the UV-irradiated phages or their DNA in hcr cells. The repair mechanism under study also effectively repairs lesions induced by polyfunctional alkylating agents in the transfecting DNA's of B. subtilis phages but is not functional with lesions induced by these agents in free phages and lesions caused in the phages and their DNA by ethyl methanesulphonate or γ radiation. (author)

  13. Activation of Saccharomyces cerevisiae Mlh1-Pms1 Endonuclease in a Reconstituted Mismatch Repair System*

    Science.gov (United States)

    Smith, Catherine E.; Bowen, Nikki; Graham, William J.; Goellner, Eva M.; Srivatsan, Anjana; Kolodner, Richard D.

    2015-01-01

    Previous studies reported the reconstitution of an Mlh1-Pms1-independent 5′ nick-directed mismatch repair (MMR) reaction using Saccharomyces cerevisiae proteins. Here we describe the reconstitution of a mispair-dependent Mlh1-Pms1 endonuclease activation reaction requiring Msh2-Msh6 (or Msh2-Msh3), proliferating cell nuclear antigen (PCNA), and replication factor C (RFC) and a reconstituted Mlh1-Pms1-dependent 3′ nick-directed MMR reaction requiring Msh2-Msh6 (or Msh2-Msh3), exonuclease 1 (Exo1), replication protein A (RPA), RFC, PCNA, and DNA polymerase δ. Both reactions required Mg2+ and Mn2+ for optimal activity. The MMR reaction also required two reaction stages in which the first stage required incubation of Mlh1-Pms1 with substrate DNA, with or without Msh2-Msh6 (or Msh2-Msh3), PCNA, and RFC but did not require nicking of the substrate, followed by a second stage in which other proteins were added. Analysis of different mutant proteins demonstrated that both reactions required a functional Mlh1-Pms1 endonuclease active site, as well as mispair recognition and Mlh1-Pms1 recruitment by Msh2-Msh6 but not sliding clamp formation. Mutant Mlh1-Pms1 and PCNA proteins that were defective for Exo1-independent but not Exo1-dependent MMR in vivo were partially defective in the Mlh1-Pms1 endonuclease and MMR reactions, suggesting that both reactions reflect the activation of Mlh1-Pms1 seen in Exo1-independent MMR in vivo. The availability of this reconstituted MMR reaction should now make it possible to better study both Exo1-independent and Exo1-dependent MMR. PMID:26170454

  14. Phase equilibria and molecular interaction studies on (naphthols + vanillin) systems

    International Nuclear Information System (INIS)

    Gupta, Preeti; Agrawal, Tanvi; Das, Shiva Saran; Singh, Nakshatra Bahadur

    2012-01-01

    Highlights: ► Phase equilibria of (naphthol + vanillin) systems have been studied for the first time. ► Eutectic type phase diagrams are obtained. ► Eutectic mixtures show nonideal behaviour. ► There is a weak molecular interaction between the components in the eutectic mixtures. ► α-Naphthol–vanillin eutectic is more stable as compared to β-naphthol–vanillin. - Abstract: Phase equilibria between (α-naphthol + vanillin) and (β-naphthol + vanillin) systems have been studied by thaw-melt method and the results show the formation of simple eutectic mixtures. Crystallization velocities of components and eutectic mixtures were determined at different stages under cooling. With the help of differential scanning calorimeter (DSC), the enthalpy of fusion of components and eutectic mixtures was determined and from the values excess thermodynamic functions viz., excess Gibbs free energy (G E ), excess entropy (S E ), excess enthalpy (H E ) of hypo-, hyper- and eutectic mixtures were calculated. Flexural strength measurements were made in order to understand the non-ideal nature of eutectics. FT-IR spectral studies indicate the formation of hydrogen bond in the eutectic mixture. Anisotropic and isotropic microstructural studies of components, hypo-, hyper- and eutectic mixtures were made. Jackson’s roughness parameter was calculated and found to be greater than 2 suggesting the faceted morphology with irregular structures. The overall results have shown that there is a weak molecular interaction between the components in the eutectic mixtures and the (α-naphthol + vanillin) eutectic is more stable as compared to the (β-naphthol + vanillin) eutectic system.

  15. The role of the DNA repair system in increasing the viability of E.coli cells under the action of small UV doses

    International Nuclear Information System (INIS)

    Kuzin, A.M.; Vilenchik, M.M.; Isakov, B.K.; AN Kazakhskoj SSR, Alma-Ata. Inst. Botaniki)

    1976-01-01

    The authors studied the action of the ultraviolet light (UV) on the colony-forming ability of E.coli K12-HCR + cultured in a meat infusion broth in the presence of glucose. An unusual shape of the curve indicates that the number of viable cells increases under the action of low UV doses. The experiment was repeated seven times, and each time the phenomenon was fully asserted (p 0.01). So it was suggested that low UV doses (about 140 erg/mm 2 ) activate the system of dark DNA repair (induction of the synthesis of repair enzymes) which repairs 'spontaneous' DNA defects and increases the number of colony-forming cells. (orig.) [de

  16. Role of the DNA repair system in increasing the viability of E. coli cells under the action of small UV doses

    Energy Technology Data Exchange (ETDEWEB)

    Kuzin, A M; Vilenchik, M M; Isakov, B K [AN SSSR, Pushchino-na-Oke. Inst. Biologicheskoj Fiziki; AN Kazakhskoj SSR, Alma-Ata. Inst. Botaniki)

    1976-12-01

    The authors studied the action of the ultraviolet light (UV) on the colony-forming ability of E.coli K12-HCR/sup +/ cultured in a meat infusion broth in the presence of glucose. An unusual shape of the curve indicates that the number of viable cells increases under the action of low UV doses. The experiment was repeated seven times, and each time the phenomenon was fully asserted (p 0.01). So it was suggested that low UV doses (about 140 erg/mm/sup 2/) activate the system of dark DNA repair (induction of the synthesis of repair enzymes) which repairs 'spontaneous' DNA defects and increases the number of colony-forming cells.

  17. Establishment of a non-radioactive cleavage assay to assess the DNA repair capacity towards oxidatively damaged DNA in subcellular and cellular systems and the impact of copper

    International Nuclear Information System (INIS)

    Hamann, Ingrit; Schwerdtle, Tanja; Hartwig, Andrea

    2009-01-01

    Oxidative stress is involved in many diseases, and the search for appropriate biomarkers is one major focus in molecular epidemiology. 8-Oxoguanine (8-oxoG), a potentially mutagenic DNA lesion, is considered to be a sensitive biomarker for oxidative stress. Another approach consists in assessing the repair capacity towards 8-oxoG, mediated predominantly by the human 8-oxoguanine DNA glycosylase 1 (hOGG1). With respect to the latter, during the last few years so-called cleavage assays have been described, investigating the incision of 32 P-labelled and 8-oxoG damaged oligonucleotides by cell extracts. Within the present study, a sensitive non-radioactive test system based on a Cy5-labelled oligonucleotide has been established. Sources of incision activity are isolated proteins or extracts prepared from cultured cells and peripheral blood mononuclear cells (PBMC). After comparing different oligonucleotide structures, a hairpin-like structure was selected which was not degraded by cell extracts. Applying this test system the impact of copper on the activity of isolated hOGG1 and on hOGG activity in A549 cells was examined, showing a distinct inhibition of the isolated protein at low copper concentration as compared to a modest inhibition of hOGG activity in cells at beginning cytotoxic concentrations. For investigating PBMC, all reaction conditions, including the amounts of oligonucleotide and cell extract as well as the reaction time have been optimized. The incision activities of PBMC protein extracts obtained from different donors have been investigated, and inter-individual differences have been observed. In summary, the established method is as sensitive and even faster than the radioactive technique, and additionally, offers the advantage of reduced costs and low health risk.

  18. Charge migration and charge transfer in molecular systems

    Directory of Open Access Journals (Sweden)

    Hans Jakob Wörner

    2017-11-01

    Full Text Available The transfer of charge at the molecular level plays a fundamental role in many areas of chemistry, physics, biology and materials science. Today, more than 60 years after the seminal work of R. A. Marcus, charge transfer is still a very active field of research. An important recent impetus comes from the ability to resolve ever faster temporal events, down to the attosecond time scale. Such a high temporal resolution now offers the possibility to unravel the most elementary quantum dynamics of both electrons and nuclei that participate in the complex process of charge transfer. This review covers recent research that addresses the following questions. Can we reconstruct the migration of charge across a molecule on the atomic length and electronic time scales? Can we use strong laser fields to control charge migration? Can we temporally resolve and understand intramolecular charge transfer in dissociative ionization of small molecules, in transition-metal complexes and in conjugated polymers? Can we tailor molecular systems towards specific charge-transfer processes? What are the time scales of the elementary steps of charge transfer in liquids and nanoparticles? Important new insights into each of these topics, obtained from state-of-the-art ultrafast spectroscopy and/or theoretical methods, are summarized in this review.

  19. Evidence for systems-level molecular mechanisms of tumorigenesis

    Directory of Open Access Journals (Sweden)

    Capellá Gabriel

    2007-06-01

    Full Text Available Abstract Background Cancer arises from the consecutive acquisition of genetic alterations. Increasing evidence suggests that as a consequence of these alterations, molecular interactions are reprogrammed in the context of highly connected and regulated cellular networks. Coordinated reprogramming would allow the cell to acquire the capabilities for malignant growth. Results Here, we determine the coordinated function of cancer gene products (i.e., proteins encoded by differentially expressed genes in tumors relative to healthy tissue counterparts, hereafter referred to as "CGPs" defined as their topological properties and organization in the interactome network. We show that CGPs are central to information exchange and propagation and that they are specifically organized to promote tumorigenesis. Centrality is identified by both local (degree and global (betweenness and closeness measures, and systematically appears in down-regulated CGPs. Up-regulated CGPs do not consistently exhibit centrality, but both types of cancer products determine the overall integrity of the network structure. In addition to centrality, down-regulated CGPs show topological association that correlates with common biological processes and pathways involved in tumorigenesis. Conclusion Given the current limited coverage of the human interactome, this study proposes that tumorigenesis takes place in a specific and organized way at the molecular systems-level and suggests a model that comprises the precise down-regulation of groups of topologically-associated proteins involved in particular functions, orchestrated with the up-regulation of specific proteins.

  20. Multiscale Molecular Dynamics Model for Heterogeneous Charged Systems

    Science.gov (United States)

    Stanton, L. G.; Glosli, J. N.; Murillo, M. S.

    2018-04-01

    Modeling matter across large length scales and timescales using molecular dynamics simulations poses significant challenges. These challenges are typically addressed through the use of precomputed pair potentials that depend on thermodynamic properties like temperature and density; however, many scenarios of interest involve spatiotemporal variations in these properties, and such variations can violate assumptions made in constructing these potentials, thus precluding their use. In particular, when a system is strongly heterogeneous, most of the usual simplifying assumptions (e.g., spherical potentials) do not apply. Here, we present a multiscale approach to orbital-free density functional theory molecular dynamics (OFDFT-MD) simulations that bridges atomic, interionic, and continuum length scales to allow for variations in hydrodynamic quantities in a consistent way. Our multiscale approach enables simulations on the order of micron length scales and 10's of picosecond timescales, which exceeds current OFDFT-MD simulations by many orders of magnitude. This new capability is then used to study the heterogeneous, nonequilibrium dynamics of a heated interface characteristic of an inertial-confinement-fusion capsule containing a plastic ablator near a fuel layer composed of deuterium-tritium ice. At these scales, fundamental assumptions of continuum models are explored; features such as the separation of the momentum fields among the species and strong hydrogen jetting from the plastic into the fuel region are observed, which had previously not been seen in hydrodynamic simulations.

  1. Development of an auto-welding system for CRD nozzle repair welds using a 3D laser vision sensor

    International Nuclear Information System (INIS)

    Park, K.; Kim, Y.; Byeon, J.; Sung, K.; Yeom, C.; Rhee, S.

    2007-01-01

    A control rod device (CRD) nozzle attaches to the hemispherical surface of a reactor head with J-groove welding. Primary water stress corrosion cracking (PWSCC) causes degradation in these welds, which requires that these defect areas be repaired. To perform this repair welding automatically on a complicated weld groove shape, an auto-welding system was developed incorporating a laser vision sensor that measures the 3-dimensional (3D) shape of the groove and a weld-path creation program that calculates the weld-path parameters. Welding trials with a J-groove workpiece were performed to establish a basis for developing this auto-welding system. Because the reactor head is placed on a lay down support, the outer-most region of the CRD nozzle has restricted access. Due to this tight space, several parameters of the design, such as size, weight and movement of the auto-welding system, had to be carefully considered. The cross section of the J-groove weld is basically an oval shape where the included angle of the J-groove ranges from 0 to 57 degrees. To measure the complex shape, we used double lasers coupled to a single charge coupled device (CCD) camera. We then developed a program to generate the weld-path parameters using the measured 3D shape as a basis. The program has the ability to determine the first and final welding positions and to calculate all weld-path parameters. An optimized image-processing algorithm was applied to resolve noise interference and diffused reflection of the joint surfaces. The auto-welding system is composed of a 4-axis manipulator, gas tungsten arc welding (GTAW) power supply, an optimized designed and manufactured GTAW torch and a 3D laser vision sensor. Through welding trials with 0 and 38-degree included-angle workpieces with both J-groove and U-groove weld, the performance of this auto-welding system was qualified for field application

  2. The INNOVATION Trial: four-year safety and effectiveness of the INCRAFT® AAA Stent-Graft System for endovascular repair.

    Science.gov (United States)

    Pratesi, Giovanni; Pratesi, Carlo; Chiesa, Roberto; Coppi, Gioacchino; Scheinert, Dierk; Brunkwall, Jan S; van der Meulen, Stefaan; Torsello, Giovanni

    2017-10-01

    This paper reports the 4-year safety and effectiveness of the INCRAFT® AAA Stent-Graft System (Cordis Corp., Milpitas, CA, USA), an ultra-low-profile device for the treatment of abdominal aortic aneurysms. The INNOVATION Trial is the prospective, first-in-human, multicenter trial to evaluate the safety and effectiveness of the INCRAFT® System. Patients underwent annual clinical and computed tomography angiography examination as part of the study protocol. The INCRAFT® AAA Stent-Graft System is a customizable tri-modular design, with an ultra-low profile (14-Fr) delivery system. Patient were treated under approved protocol, the prescribed clinical and imaging follow-up at annually through 5 years. Results analyzed and adjudicated by a clinical events committee, independent core laboratory, and a data safety and monitoring board. This manuscript reports results through 4 years of follow-up. A total of 60 patients were enrolled in the trial, all of whom were successfully treated. Follow-up rates at 1 and 4 years were 93% (56/60) and 85% (51/60), respectively. All-cause mortality at 4 years was 17.6% and no death was AAA-, device-, or procedure-related. The secondary reintervention rate at 1 year was 4.6%, primarily the result of stent thrombosis. In total, 10 patients required 13 post-procedure interventions within 4-years of follow-up (2 to repair a type I endoleak, 4 to repair a type II endoleak, 1 for stent thrombosis, 1 for renal stenosis, 1 for aneurysm enlargement, 2 for limb migration and 2 for prosthesis stenosis or occlusion). There were 4 cases (10%) of aneurysm enlargement reported at the 4 year follow-up. At 4 years, 38 out of 39 patients were free from type I and III endoleaks. There were no proximal type I or type III endoleaks at 4-year follow-up. Core laboratory evaluation of the postoperative imaging studies indicated absence of endograft migration while a single fracture was demonstrated without any clinical sequelae. The INCRAFT® AAA Stent

  3. Molecular dynamic simulations of the sputtering of multilayer organic systems

    CERN Document Server

    Postawa, Z; Piaskowy, J; Krantzman, K; Winograd, N; Garrison, B J

    2003-01-01

    Sputtering of organic overlayers has been modeled using molecular dynamics computer simulations. The investigated systems are composed of benzene molecules condensed into one, two and three layers on an Ag left brace 1 1 1 right brace surface. The formed organic overlayers were bombarded with 4 keV Ar projectiles at normal incidence. The development of the collision cascade in the organic overlayer was investigated. The sputtering yield, mass, internal and kinetic energy distributions of ejected particles have been analyzed as a function of the thickness of the organic layer. The results show that all emission characteristics are sensitive to the variation of layer thickness. Although most of the ejected intact benzene molecules originate from the topmost layer, the emission of particles located initially in second and third layers is significant. The analysis indicates that the metallic substrate plays a dominant role in the ejection of intact organic molecules.

  4. Pancreatic Cancer Gene Therapy: From Molecular Targets to Delivery Systems

    Energy Technology Data Exchange (ETDEWEB)

    Fillat, Cristina, E-mail: cristina.fillat@crg.es; Jose, Anabel; Ros, Xavier Bofill-De; Mato-Berciano, Ana; Maliandi, Maria Victoria; Sobrevals, Luciano [Programa Gens i Malaltia, Centre de Regulació Genòmica-CRG, UPF, Parc de Recerca Biomedica de Barcelona-PRBB and Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Barcelona (Spain)

    2011-01-18

    The continuous identification of molecular changes deregulating critical pathways in pancreatic tumor cells provides us with a large number of novel candidates to engineer gene-targeted approaches for pancreatic cancer treatment. Targets—both protein coding and non-coding—are being exploited in gene therapy to influence the deregulated pathways to facilitate cytotoxicity, enhance the immune response or sensitize to current treatments. Delivery vehicles based on viral or non-viral systems as well as cellular vectors with tumor homing characteristics are a critical part of the design of gene therapy strategies. The different behavior of tumoral versus non-tumoral cells inspires vector engineering with the generation of tumor selective products that can prevent potential toxic-associated effects. In the current review, a detailed analysis of the different targets, the delivery vectors, the preclinical approaches and a descriptive update on the conducted clinical trials are presented. Moreover, future possibilities in pancreatic cancer treatment by gene therapy strategies are discussed.

  5. Isolating strong-field dynamics in molecular systems

    Science.gov (United States)

    Orenstein, Gal; Pedatzur, Oren; Uzan, Ayelet J.; Bruner, Barry D.; Mairesse, Yann; Dudovich, Nirit

    2017-05-01

    Strong-field ionization followed by recollision provides a unique pump-probe measurement which reveals a range of electronic processes, combining sub-Angstrom spatial and attosecond temporal resolution. A major limitation of this approach is imposed by the coupling between the spatial and temporal degrees of freedom. In this paper we focus on the study of high harmonic generation and demonstrate the ability to isolate the internal dynamics—decoupling the temporal information from the spatial one. By applying an in situ approach we reveal the universality of the intrinsic pump-probe measurement and establish its validity in molecular systems. When several orbitals are involved we identify the fingerprint of the transition from the single-channel case into the multiple-channel dynamics, where complex multielectron phenomena are expected to be observed.

  6. Mitek Anchor System: a new technique for tenodesis and ligamentous repair of the foot and ankle.

    Science.gov (United States)

    Pederson, B; Tesoro, D; Wertheimer, S J; Coraci, M

    1991-01-01

    The authors present an alternative method for securing tendon and ligaments to bone, utilizing the Mitek Anchor System. The description of the Mitek system and technique of application is presented. Technical simplicity and ease of adaptability within the foot and ankle are distinct advantages of this System.

  7. On Birnbaum importance assessment for aging multi-state system under minimal repair by using the Lz-transform method

    International Nuclear Information System (INIS)

    Lisnianski, Anatoly; Frenkel, Ilia; Khvatskin, Lev

    2015-01-01

    This paper considers a reliability importance evaluation for components in an aging multi-state system. In practical reliability engineering a “curse of dimensionality” (the large number of states that should be analyzed for a multi-state system model) is a main obstacle for importance assessment. In order to challenge the problem, this paper proposes a new method that is based on an L Z -transform of the discrete-state continuous-time Markov process and on Ushakov's Universal Generating Operator. The paper shows that the proposed method can drastically reduce a computational burden. In order to illustrate the method, a solution of a real world problem is presented as a numerical example. - Highlights: • Aging multi-state system under minimal repair is studied. • A new method for Birnbaum importance assessment is developed. • The method is based on the L Z -transform. • The proposed method provides a drastic reduction of computation burden. • Numerical example is presented in order to illustrate the method

  8. Some important advances in DNA repair study on the mammalian cells

    International Nuclear Information System (INIS)

    Xia Shouxuan.

    1991-01-01

    In the recent years the study of DNA damage and repair in the mammalian cells has gone deeply at gene level and got the following advances: (1) For a long time DNA has been considered to be an uniform unit in case of damage and repair. Now this concept should be replaced by the non-random distribution of damage and heterogenous repair in the genome. These would allow us to study cellular mutagenesis, carcinogenesis, aging and dying processes in great detail, and would be beneficial to the elucidation of mechanisms of radiation sickness and chemical toxicology. (2) The advent of new techniques in molecular biology has made it possible to isolate and clone the human DNA repair genes. Up to now more than ten human DNA repair genes have been cloned and these works would have an important impact on the theoretical and practical study in this field. Because DNA repair system is very complicate, voluminous work should be done in the future. (3) The technique of gene transfer has been efficiently used in the study of DNA repair in mammalian cells and has made great contribution in the cellular engineering. It could modify the genetic behavior of the gene-accepting cells, and enhance the DNA repair ability to physical and chemical damages. Human gene therapy for DNA deficient diseases is now on the day

  9. Reliability measures of a computer system with priority to PM over the H/W repair activities subject to MOT and MRT

    Directory of Open Access Journals (Sweden)

    Ashish Kumar

    2015-01-01

    Full Text Available This paper concentrates on the evaluation of reliability measures of a computer system of two-identical units having independent failure of h/w and s/w components. Initially one unit is operative and the other is kept as spare in cold standby. There is a single server visiting the system immediately whenever needed. The server conducts preventive maintenance of the unit after a maximum operation time. If server is unable to repair the h/w components in maximum repair time, then components in the unit are replaced immediately by new one. However, only replacement of the s/w components has been made at their failure. The priority is given to the preventive maintenance over repair activities of the h/w. The time to failure of the components follows negative exponential distribution whereas the distribution of preventive maintenance, repair and replacement time are taken as arbitrary. The expressions for some important reliability measures of system effectiveness have been derived using semi-Markov process and regenerative point technique. The graphical behavior of the results has also been shown for a particular case.

  10. A Robotic System for Inspection and Repair of Small Diameter Pipelines

    Directory of Open Access Journals (Sweden)

    S. A. Vorotnikov

    2015-01-01

    Full Text Available This paper deals with the construction and control system of miniature robotic system that is designed to move and make inspection inside small diameter pipelines. It gives an overview of ways to move a microsize robotic system inside the small diameter pipe. The proposed design consists of information module and three traction modules, including modules for fixing, linear moving and angular positioning. This paper describes the design and operation of a robotic system and its different modules. Also are shown the structure of the robot control system, the basic calculations of construct and some simulation results of the individual modules of the robot.

  11. Discrete time analysis of a repairable machine

    OpenAIRE

    Alfa, Attahiru Sule; Castro, I. T.

    2002-01-01

    We consider, in discrete time, a single machine system that operates for a period of time represented by a general distribution. This machine is subject to failures during operations and the occurrence of these failures depends on how many times the machine has previously failed. Some failures are repairable and the repair times may or may not depend on the number of times the machine was previously repaired. Repair times also have a general distribution. The operating times...

  12. PathSys: integrating molecular interaction graphs for systems biology

    Directory of Open Access Journals (Sweden)

    Raval Alpan

    2006-02-01

    Full Text Available Abstract Background The goal of information integration in systems biology is to combine information from a number of databases and data sets, which are obtained from both high and low throughput experiments, under one data management scheme such that the cumulative information provides greater biological insight than is possible with individual information sources considered separately. Results Here we present PathSys, a graph-based system for creating a combined database of networks of interaction for generating integrated view of biological mechanisms. We used PathSys to integrate over 14 curated and publicly contributed data sources for the budding yeast (S. cerevisiae and Gene Ontology. A number of exploratory questions were formulated as a combination of relational and graph-based queries to the integrated database. Thus, PathSys is a general-purpose, scalable, graph-data warehouse of biological information, complete with a graph manipulation and a query language, a storage mechanism and a generic data-importing mechanism through schema-mapping. Conclusion Results from several test studies demonstrate the effectiveness of the approach in retrieving biologically interesting relations between genes and proteins, the networks connecting them, and of the utility of PathSys as a scalable graph-based warehouse for interaction-network integration and a hypothesis generator system. The PathSys's client software, named BiologicalNetworks, developed for navigation and analyses of molecular networks, is available as a Java Web Start application at http://brak.sdsc.edu/pub/BiologicalNetworks.

  13. Bicanonical ab Initio Molecular Dynamics for Open Systems.

    Science.gov (United States)

    Frenzel, Johannes; Meyer, Bernd; Marx, Dominik

    2017-08-08

    Performing ab initio molecular dynamics simulations of open systems, where the chemical potential rather than the number of both nuclei and electrons is fixed, still is a challenge. Here, drawing on bicanonical sampling ideas introduced two decades ago by Swope and Andersen [ J. Chem. Phys. 1995 , 102 , 2851 - 2863 ] to calculate chemical potentials of liquids and solids, an ab initio simulation technique is devised, which introduces a fictitious dynamics of two superimposed but otherwise independent periodic systems including full electronic structure, such that either the chemical potential or the average fractional particle number of a specific chemical species can be kept constant. As proof of concept, we demonstrate that solvation free energies can be computed from these bicanonical ab initio simulations upon directly superimposing pure bulk water and the respective aqueous solution being the two limiting systems. The method is useful in many circumstances, for instance for studying heterogeneous catalytic processes taking place on surfaces where the chemical potential of reactants rather than their number is controlled and opens a pathway toward ab initio simulations at constant electrochemical potential.

  14. Parametrizing coarse grained models for molecular systems at equilibrium

    KAUST Repository

    Kalligiannaki, Evangelia; Chazirakis, A.; Tsourtis, A.; Katsoulakis, M. A.; Plechá č, P.; Harmandaris, V.

    2016-01-01

    Hierarchical coarse graining of atomistic molecular systems at equilibrium has been an intensive research topic over the last few decades. In this work we (a) review theoretical and numerical aspects of different parametrization methods (structural-based, force matching and relative entropy) to derive the effective interaction potential between coarse-grained particles. All methods approximate the many body potential of mean force; resulting, however, in different optimization problems. (b) We also use a reformulation of the force matching method by introducing a generalized force matching condition for the local mean force in the sense that allows the approximation of the potential of mean force under both linear and non-linear coarse graining mappings (E. Kalligiannaki, et al., J. Chem. Phys. 2015). We apply and compare these methods to: (a) a benchmark system of two isolated methane molecules; (b) methane liquid; (c) water; and (d) an alkane fluid. Differences between the effective interactions, derived from the various methods, are found that depend on the actual system under study. The results further reveal the relation of the various methods and the sensitivities that may arise in the implementation of numerical methods used in each case.

  15. Parametrizing coarse grained models for molecular systems at equilibrium

    KAUST Repository

    Kalligiannaki, Evangelia

    2016-10-18

    Hierarchical coarse graining of atomistic molecular systems at equilibrium has been an intensive research topic over the last few decades. In this work we (a) review theoretical and numerical aspects of different parametrization methods (structural-based, force matching and relative entropy) to derive the effective interaction potential between coarse-grained particles. All methods approximate the many body potential of mean force; resulting, however, in different optimization problems. (b) We also use a reformulation of the force matching method by introducing a generalized force matching condition for the local mean force in the sense that allows the approximation of the potential of mean force under both linear and non-linear coarse graining mappings (E. Kalligiannaki, et al., J. Chem. Phys. 2015). We apply and compare these methods to: (a) a benchmark system of two isolated methane molecules; (b) methane liquid; (c) water; and (d) an alkane fluid. Differences between the effective interactions, derived from the various methods, are found that depend on the actual system under study. The results further reveal the relation of the various methods and the sensitivities that may arise in the implementation of numerical methods used in each case.

  16. Molecular tailoring of interfaces for thin film on substrate systems

    Science.gov (United States)

    Grady, Martha Elizabeth

    Thin film on substrate systems appear most prevalently within the microelectronics industry, which demands that devices operate in smaller and smaller packages with greater reliability. The reliability of these multilayer film systems is strongly influenced by the adhesion of each of the bimaterial interfaces. During use, microelectronic components undergo thermo-mechanical cycling, which induces interfacial delaminations leading to failure of the overall device. The ability to tailor interfacial properties at the molecular level provides a mechanism to improve thin film adhesion, reliability and performance. This dissertation presents the investigation of molecular level control of interface properties in three thin film-substrate systems: photodefinable polyimide films on passivated silicon substrates, self-assembled monolayers at the interface of Au films and dielectric substrates, and mechanochemically active materials on rigid substrates. For all three materials systems, the effect of interfacial modifications on adhesion is assessed using a laser-spallation technique. Laser-induced stress waves are chosen because they dynamically load the thin film interface in a precise, noncontacting manner at high strain rates and are suitable for both weak and strong interfaces. Photodefinable polyimide films are used as dielectrics in flip chip integrated circuit packages to reduce the stress between silicon passivation layers and mold compound. The influence of processing parameters on adhesion is examined for photodefinable polyimide films on silicon (Si) substrates with three different passivation layers: silicon nitride (SiNx), silicon oxynitride (SiOxNy), and the native silicon oxide (SiO2). Interfacial strength increases when films are processed with an exposure step as well as a longer cure cycle. Additionally, the interfacial fracture energy is assessed using a dynamic delamination protocol. The high toughness of this interface (ca. 100 J/m2) makes it difficult

  17. Meniscal repair devices.

    Science.gov (United States)

    Barber, F A; Herbert, M A

    2000-09-01

    Meniscal repair devices not requiring accessory incisions are attractive. Many factors contribute to their clinical effectiveness including their biomechanical characteristics. This study compared several new meniscal repair devices with standard meniscal suture techniques. Using a porcine model, axis-of-insertion loads were applied to various meniscal sutures and repair devices. A single device or stitch was placed in a created meniscal tear and a load applied. Both loads and modes of failure were recorded. The load-to-failure data show stratification into 4 distinct statistical groups. Group A, 113 N for a double vertical stitch; group B, 80 N for a single vertical stitch; group C, 57 N for the BioStinger, 56 N for a horizontal mattress stitch, and 50 N for the T-Fix stitch; and group D, 33 N for the Meniscus Arrow (inserted by hand or gun), 32 N for the Clearfix screw, 31 N for the SDsorb staple, 30 N for the Mitek meniscal repair system, and 27 N for the Biomet staple. The failure mechanism varied. Sutures broke away from the knot. The Meniscus Arrow and BioStinger pulled through the inner rim with the crossbar intact. The Clearfix screw failed by multiple mechanisms, whereas 1 leg of the SDsorb staple always pulled out of the outer rim. The Mitek device usually failed by pullout from the inner rim. The Biomet staple always broke at the crosshead or just below it. Although the surgeon should be aware of the material properties of the repair technique chosen for a meniscal repair, this information is only an indication of device performance and may not correlate with clinical healing results.

  18. Quantitative MRI comparison of systemic hemodynamics in Mustard/Senning repaired patients and healthy volunteers at rest

    International Nuclear Information System (INIS)

    Laffon, Eric; Jimenez, Maria; Choussat, Alain; Latrabe, Valerie; Ducassou, Dominique; Marthan, Roger; Laurent, Francois

    2004-01-01

    The purpose of the present study was to non-invasively compare ascending aortic blood flow and cross-sectional area (CSA) variations vs time in Mustard or Senning repaired (MSR) patients against those of healthy volunteers at rest. Velocity-encoded MR imaging was performed in 10 male patients (age range 18-24 years, median age 20.5 years) late after a Mustard or Senning correction, and in 10 male healthy volunteers (age range 21-25 years, median age 22.5 years), at the upper part of the ascending aorta. Both aortic cross-sectional area (CSA) and blood-flow variations were recorded over a complete cardiac cycle, with a 30-ms time of resolution. The body-surface area (BSA), the mean CSA over the systolic phase, and the BSA-normalized systemic ventricle power and work were significantly lower in the patient series compared with those of the volunteer series. The BSA-normalized right ventricle (RV) power and work of MSR patients were equal to 87 and 83% on average of those of the left ventricle (LV) of healthy volunteers. We conclude that, at rest, the mechanical performance of the systemic RV in MSR patients is significantly lower than that of the LV in healthy volunteers. Furthermore, the significantly lower aortic CSA found in MSR patients than in healthy volunteers may reveal an increase in the vasomotor tone. (orig.)

  19. Procedures for maintenance and repairs

    International Nuclear Information System (INIS)

    Pickel, E.

    1981-01-01

    After a general review of the operation experience in the history of more than 12 operating years, the organization in the plant will be shown with special aspect to quality assurance, capacity of the workshops and connected groups as radiation protection, chemical laboratories etc. The number, time intervals and manpower effort for the repeating tests will be discussed. Reasons and examples for back-fitting activities in the plant are given. Besides special repair and maintenance procedures as repair of the steam generators, in-service inspection of the reactor pressure vessel, repair of a feed-water pipe and repair of the core structure in the pressure vessel, the general system to handle maintenance and repair-work in the KWO-plant will be shown. This includes also the detailed planning of the annual refueling and revision of the plant. (orig./RW)

  20. Molecular Physiology of Root System Architecture in Model Grasses

    Science.gov (United States)

    Hixson, K.; Ahkami, A. H.; Anderton, C.; Veličković, D.; Myers, G. L.; Chrisler, W.; Lindenmaier, R.; Fang, Y.; Yabusaki, S.; Rosnow, J. J.; Farris, Y.; Khan, N. E.; Bernstein, H. C.; Jansson, C.

    2017-12-01

    Unraveling the molecular and physiological mechanisms involved in responses of Root System Architecture (RSA) to abiotic stresses and shifts in microbiome structure is critical to understand and engineer plant-microbe-soil interactions in the rhizosphere. In this study, accessions of Brachypodium distachyon Bd21 (C3 model grass) and Setaria viridis A10.1 (C4 model grass) were grown in phytotron chambers under current and elevated CO2 levels. Detailed growth stage-based phenotypic analysis revealed different above- and below-ground morphological and physiological responses in C3 and C4 grasses to enhanced CO2 levels. Based on our preliminary results and by screening values of total biomass, water use efficiency, root to shoot ratio, RSA parameters and net assimilation rates, we postulated a three-phase physiological mechanism, i.e. RootPlus, BiomassPlus and YieldPlus phases, for grass growth under elevated CO2 conditions. Moreover, this comprehensive set of morphological and process-based observations are currently in use to develop, test, and calibrate biophysical whole-plant models and in particular to simulate leaf-level photosynthesis at various developmental stages of C3 and C4 using the model BioCro. To further link the observed phenotypic traits at the organismal level to tissue and molecular levels, and to spatially resolve the origin and fate of key metabolites involved in primary carbohydrate metabolism in different root sections, we complement root phenotypic observations with spatial metabolomics data using mass spectrometry imaging (MSI) methods. Focusing on plant-microbe interactions in the rhizosphere, six bacterial strains with plant growth promoting features are currently in use in both gel-based and soil systems to screen root growth and development in Brachypodium. Using confocal microscopy, GFP-tagged bacterial systems are utilized to study the initiation of different root types of RSA, including primary root (PR), coleoptile node axile root (CNR

  1. Inspection, maintenance, and repair of large pumps and piping systems using advanced robotic tools

    International Nuclear Information System (INIS)

    Lewis, R.K.; Radigan, T.M.

    1998-01-01

    Operating and maintaining large pumps and piping systems can be an expensive proposition. Proper inspections and monitoring can reduce costs. This was difficult in the past, since detailed pump inspections could only be performed by disassembly and many portions of piping systems are buried or covered with insulation. Once these components were disassembled, a majority of the cost was already incurred. At that point, expensive part replacement usually took place whether it was needed or not. With the completion of the Pipe Walkertrademark/LIP System and the planned development of the Submersible Walkertrademark, this situation is due to change. The specifications for these inspection and maintenance robots will ensure that. Their ability to traverse both horizontal and vertical, forward and backward, make them unique tools. They will open the door for some innovative approaches to inspection and maintenance of large pumps and piping systems

  2. An Analysis of the Reflector Cooling System Repair Status after the Initial Operation of HANARO

    Energy Technology Data Exchange (ETDEWEB)

    Park, Young Chul; Seo, Kyoung Woo; Chi, Dae Young; Yoon, Hyun Gi [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Park, Jung Geun [Safety Evaluation Department, System D and D Co., Daejeon (Korea, Republic of)

    2011-05-15

    HANARO, an open-tank-in-pool type multi-purpose research reactor of 30 MWth power in Korea, has been operating normally since its initial criticality in February, 1995. During the last operation period of HANARO, when a trouble occurred, the trouble was fixed on site. As preventive maintenance can reduce the corrective maintenance, the reasons of the occurred troubles are reviewed to prepare preventive maintenance. About twelve hundred cases of work requests and nonconformance reports (NCRs) have been issued since the initial criticality of HANARO. The cases are analyzed according to the trouble status, the trouble equipment function and the cause of the major trouble for reflector cooling system (RCS, hereinafter) including cover gas system and leakage monitoring and collection system

  3. Tension (re)builds: Biophysical mechanisms of embryonic wound repair.

    Science.gov (United States)

    Zulueta-Coarasa, Teresa; Fernandez-Gonzalez, Rodrigo

    2017-04-01

    Embryonic tissues display an outstanding ability to rapidly repair wounds. Epithelia, in particular, serve as protective layers that line internal organs and form the skin. Thus, maintenance of epithelial integrity is of utmost importance for animal survival, particularly at embryonic stages, when an immune system has not yet fully developed. Rapid embryonic repair of epithelial tissues is conserved across species, and involves the collective migration of the cells around the wound. The migratory cell behaviours associated with wound repair require the generation and transmission of mechanical forces, not only for the cells to move, but also to coordinate their movements. Here, we review the forces involved in embryonic wound repair. We discuss how different force-generating structures are assembled at the molecular level, and the mechanisms that maintain the balance between force-generating structures as wounds close. Finally, we describe the mechanisms that cells use to coordinate the generation of mechanical forces around the wound. Collective cell movements and their misregulation have been associated with defective tissue repair, developmental abnormalities and cancer metastasis. Thus, we propose that understanding the role of mechanical forces during embryonic wound closure will be crucial to develop therapeutic interventions that promote or prevent collective cell movements under pathological conditions. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  4. Spectroscopic Studies of Molecular Systems relevant in Astrobiology

    Science.gov (United States)

    Fornaro, Teresa

    2016-01-01

    In the Astrobiology context, the study of the physico-chemical interactions involving "building blocks of life" in plausible prebiotic and space-like conditions is fundamental to shed light on the processes that led to emergence of life on Earth as well as to molecular chemical evolution in space. In this PhD Thesis, such issues have been addressed both experimentally and computationally by employing vibrational spectroscopy, which has shown to be an effective tool to investigate the variety of intermolecular interactions that play a key role in self-assembling mechanisms of nucleic acid components and their binding to mineral surfaces. In particular, in order to dissect the contributions of the different interactions to the overall spectroscopic signals and shed light on the intricate experimental data, feasible computational protocols have been developed for the characterization of the spectroscopic properties of such complex systems. This study has been carried out through a multi-step strategy, starting the investigation from the spectroscopic properties of the isolated nucleobases, then studying the perturbation induced by the interaction with another molecule (molecular dimers), towards condensed phases like the molecular solid, up to the case of nucleic acid components adsorbed on minerals. A proper modeling of these weakly bound molecular systems has required, firstly, a validation of dispersion-corrected Density Functional Theory methods for simulating anharmonic vibrational properties. The isolated nucleobases and some of their dimers have been used as benchmark set for identifying a general, reliable and effective computational procedure based on fully anharmonic quantum mechanical computations of the vibrational wavenumbers and infrared intensities within the generalized second order vibrational perturbation theory (GVPT2) approach, combined with the cost-effective dispersion-corrected density functional B3LYP-D3, in conjunction with basis sets of

  5. Comparison between state graphs and fault trees for sequential and repairable systems

    International Nuclear Information System (INIS)

    Soussan, D.; Saignes, P.

    1996-01-01

    In French PSA (Probabilistic Safety Assessment) 1300 for the 1300 Mwe PWR plants carried out by EDF, sequential and reparable systems are modeled with state graphs. This method is particularly convenient for modeling dynamic systems with long-term missions but induces a bad traceability and understandability of models. In the objective of providing elements for rewriting PSA 1300 with only boolean models, EDF has asked CEA to participate to a methodological study. The aim is to carry out a feasibility study of transposition of state graphs models into fault trees on Component Cooling System and Essential Service Water System (CCS/ESWS) and to draw a methodological guide for transposition. The study realized on CCS/ESWS involves two main axes: quantification of cold source loss (as an accident sequence initiating event, called H1); quantification of the CCS/ESWS missions in accident sequences. The subject of this article is to show that this transformation is applicable with minimum distortions of the results and to determine the hypotheses, the conditions and the limits of application of this conversion. (authors). 2 refs

  6. Nuclear power plant steam pipes repairing with TIRANT 3 robot system

    International Nuclear Information System (INIS)

    Soto Tomas, Marcelo; Curiel Nieva, Marceliano; Monzo Blasco, Enrique; Rodriguez, Salvador Pineda; Vaquer Perez, Juan I.

    2011-01-01

    A typical application functions covering the steam pipes inner surface in coal-fired power station and nuclear power plants. The results of this process are spectacular in terms of protection against corrosion and abrasion, but its application has conditioning factors, such as: Severe application conditions for workers. Due to the postural position (usually kneeling) in small diameter pipes and working with fireproof clothing and masks with outdoor air supplying, due to fumes, sparks and molten metal particles, radiological contamination, confined space, poor lighting... Coating uniformity. As metallization is a manual process, the carried out measurements show small variations in the thickness of the coating, always within the tolerance limits established by the applicable regulations and quality assurance. For all these reasons, Grupo Dominguis has developed the TIRANT 3 robot, a worldwide innovative system, for metallization of steam pipes inner surface. TIRANT 3 robot is teleoperated from outside of the pipe, so that human intervention is reduced to the operations of robot positioning and change of metallization wire. As it is an independent system of the human factor, metallization process performance is significantly increased by reducing rest periods due only to the robot maintenance. Likewise, TIRANT 3 system permits to increase resulting coating uniformity, and thus its resistance, keeping selected parameters constant depending on required type and thickness of wire. TIRANT 3 system has successfully worked in 2010 during the stops refueling of the Units I and II of Laguna Verde nuclear power plant in Mexico. (author)

  7. Incorporating Flexibility in the Design of Repairable Systems - Design of Microgrids

    Science.gov (United States)

    2014-01-01

    MICROGRIDS Vijitashwa Pandey1 Annette Skowronska1,2...optimization of complex systems such as a microgrid is however, computationally intensive. The problem is exacerbated if we must incorporate...flexibility in terms of allowing the microgrid architecture and its running protocol to change with time. To reduce the computational effort, this paper

  8. Expert system for assisting the repair operations on the control racks of the control rods assembly in a 900 MW PWR type reactor

    International Nuclear Information System (INIS)

    Monnier, B.; Doutre, J.L.; Franco, A.

    1990-01-01

    The expert system presented was developed for assisting the repair operations on the control equipment of the control rod assembly in a PWR type reactor. The expert system allows the representation of expert knowledge and diagnostic reasoning. The objective of the expert system is to achieve the most precise diagnostic and localizing of the breakdown elements, by processing the data acquired during breakdown. The development steps, the structure and the applications of the expert system are summarized. The expert system operates in an IBM PC equipped with a AMAIA 8 Mo card. A time schedule of 18 months is predicted [fr

  9. 36. Anesthesia for high risk patients undergoing percutaneous mitral valve repair with the mitraclip system in the catheterization laboratory

    Directory of Open Access Journals (Sweden)

    R. Soliman

    2016-07-01

    Full Text Available MitraClip system implantation is used inhigh-risk patients with severe mitral regurgitation.anesthetic management for mitral clip implantation. The study included 34patients scheduled for MitraClip implantations in the catheterization laboratory. An arterial line and central venous line were inserted under local anesthesia before induction. Epinephrine was started before induction and milrinone infusion was started after induction. The anesthetic technique for induction and maintenance was the same for all patients. All patients were hemodynamically stable intra- and postoperatively. The intervention was successful in 33 cases and aborted in one case because of severe posteromedial leaflet tethering. The epinephrine and milrinone were weaned and all patients were extubated, except, one case mortality happened within the first 8 hours postoperatively. Percutaneous mitral valve repair with MitraClip implantation is a successful alternative in high-risk patients with symptomatic severe mitral regurgitation. Starting epinephrine before anesthetic induction and milrinone infusion induction resulted in decreased pulmonary artery pressure, increased ejection fraction and maintained arterial blood pressure during procedure inspite of worse preoperative conditions.

  10. Nuclear Power Plant Steam Pipes repairing with Tirant 3R Robot System

    International Nuclear Information System (INIS)

    Ruiz-Martinez, Jose-Tomas; Soto-Tomas, Marcelo; Curiel-Nieva, Marceliano; Monzo-Blasco, Enrique; Pineda-Rodriguez, Salvador; Vaquer-Perez, Juan-Ignacio

    2012-09-01

    The metallization arc spray process is based on the projection of molten metal, supplied by means of different stainless alloys wire, over a surface of carbon steel usually, with the object of serving as protection against flow assisted corrosion (FAC), increasing resistance to abrasion and deteriorations. A typical application functions covering the steam pipes inner surface in Coal-fired power station and Nuclear Power Plants. The results of this process are spectacular in terms of protection against flow assisted corrosion and abrasion, but its application has conditioning factors, such as: Severe application conditions for workers. Due to the worker's postural position (usually kneeling) in 32' diameter pipes and working with fireproof clothing and masks with outdoor air supplying, due to fumes, sparks and molten metal particles, radiological contamination, confined space, poor lighting... Coating uniformity. As metallization is a manual process, the carried out measurements show small variations in the thickness of the coating, always within the tolerance limits established by the applicable regulations and Quality Assurance. An increase in the uniformity of the projected coating, increase the resistance and give a better surface protection. For all these reasons, Lainsa has developed the TIRANT 3 R system, a worldwide innovative system, for metallization of steam pipes inner surface. TIRANT 3 R system is tele-operated from outside of the pipe, so that human intervention is reduced to the operations of robot positioning and change of metallization wire. As it is an independent system of the human factor, metallization process performance is significantly increased by reducing rest periods due only to the robot maintenance. Likewise, TIRANT 3 R system permits to increase resulting coating uniformity and thus its resistance, keeping selected parameters constant (forward speed, rotation speed and inner surface distance) depending on required type and

  11. Aircraft Propeller Hub Repair

    Energy Technology Data Exchange (ETDEWEB)

    Muth, Thomas R [ORNL; Peter, William H [ORNL

    2015-02-13

    The team performed a literature review, conducted residual stress measurements, performed failure analysis, and demonstrated a solid state additive manufacturing repair technique on samples removed from a scrapped propeller hub. The team evaluated multiple options for hub repair that included existing metal buildup technologies that the Federal Aviation Administration (FAA) has already embraced, such as cold spray, high velocity oxy-fuel deposition (HVOF), and plasma spray. In addition the team helped Piedmont Propulsion Systems, LLC (PPS) evaluate three potential solutions that could be deployed at different stages in the life cycle of aluminum alloy hubs, in addition to the conventional spray coating method for repair. For new hubs, a machining practice to prevent fretting with the steel drive shaft was recommended. For hubs that were refurbished with some material remaining above the minimal material condition (MMC), a silver interface applied by an electromagnetic pulse additive manufacturing method was recommended. For hubs that were at or below the MMC, a solid state additive manufacturing technique using ultrasonic welding (UW) of thin layers of 7075 aluminum to the hub interface was recommended. A cladding demonstration using the UW technique achieved mechanical bonding of the layers showing promise as a viable repair method.

  12. Fast electronic structure methods for strongly correlated molecular systems

    International Nuclear Information System (INIS)

    Head-Gordon, Martin; Beran, Gregory J O; Sodt, Alex; Jung, Yousung

    2005-01-01

    A short review is given of newly developed fast electronic structure methods that are designed to treat molecular systems with strong electron correlations, such as diradicaloid molecules, for which standard electronic structure methods such as density functional theory are inadequate. These new local correlation methods are based on coupled cluster theory within a perfect pairing active space, containing either a linear or quadratic number of pair correlation amplitudes, to yield the perfect pairing (PP) and imperfect pairing (IP) models. This reduces the scaling of the coupled cluster iterations to no worse than cubic, relative to the sixth power dependence of the usual (untruncated) coupled cluster doubles model. A second order perturbation correction, PP(2), to treat the neglected (weaker) correlations is formulated for the PP model. To ensure minimal prefactors, in addition to favorable size-scaling, highly efficient implementations of PP, IP and PP(2) have been completed, using auxiliary basis expansions. This yields speedups of almost an order of magnitude over the best alternatives using 4-center 2-electron integrals. A short discussion of the scope of accessible chemical applications is given

  13. Failure analysis of a repairable system: The case study of a cam-driven reciprocating pump

    Science.gov (United States)

    Dudenhoeffer, Donald D.

    1994-09-01

    This thesis supplies a statistical and economic tool for analysis of the failure characteristics of one typical piece of equipment under evaluation: a cam-driven reciprocating pump used in the submarine's distillation system. Comprehensive statistical techniques and parametric modeling are employed to identify and quantify pump failure characteristics. Specific areas of attention include: the derivation of an optimal maximum replacement interval based on costs, an evaluation of the mission reliability for the pump as a function of pump age, and a calculation of the expected times between failures. The purpose of this analysis is to evaluate current maintenance practices of time-based replacement and examine the consequences of different replacement intervals in terms of costs and mission reliability. Tradeoffs exist between cost savings and system reliability that must be fully understood prior to making any policy decisions.

  14. Ligament Augmentation and Reconstruction System Failures in Repair of Grade V Acromioclavicular Joint Dislocation

    Directory of Open Access Journals (Sweden)

    Martin K.-H. Li

    2017-01-01

    Full Text Available The Ligament Augmentation and Reconstruction System® (LARS® represents a popular synthetic anatomical reduction method for acromioclavicular joint dislocation by means of coracoclavicular ligament reconstruction. To our knowledge, no early failure has been documented in the literature. We present two unusual cases of LARS failure, one at four months after implant and the other at three weeks, without obvious causes, requiring re-do reconstruction, and discuss potential contributory factors.

  15. Pelvic organ prolapse repair using the Uphold (TM) Vaginal Support System

    OpenAIRE

    Altman, Daniel; Mikkola, Tomi S.; Bek, Karl Moller; Rahkola-Soisalo, Paivi; Gunnarsson, Jonas; Engh, Marie Ellstrom; Falconer, Christian; Nordic TVM Grp

    2016-01-01

    The objective was to assess safety and clinical outcomes in women operated on using the Uphold (TM) Lite Vaginal Support System. We carried out a 1-year, multicenter, prospective, single cohort study of 207 women with symptomatic Pelvic Organ Prolapse Quantification (POP-Q) stage aeyen2 apical pelvic organ prolapse, with or without concomitant anterior vaginal wall prolapse. Safety data were collected using a standardized questionnaire. Anatomical outcome was assessed by the POP-Q and subject...

  16. Large-scale theoretical calculations in molecular science - design of a large computer system for molecular science and necessary conditions for future computers

    Energy Technology Data Exchange (ETDEWEB)

    Kashiwagi, H [Institute for Molecular Science, Okazaki, Aichi (Japan)

    1982-06-01

    A large computer system was designed and established for molecular science under the leadership of molecular scientists. Features of the computer system are an automated operation system and an open self-service system. Large-scale theoretical calculations have been performed to solve many problems in molecular science, using the computer system. Necessary conditions for future computers are discussed on the basis of this experience.

  17. Large-scale theoretical calculations in molecular science - design of a large computer system for molecular science and necessary conditions for future computers

    International Nuclear Information System (INIS)

    Kashiwagi, H.

    1982-01-01

    A large computer system was designed and established for molecular science under the leadership of molecular scientists. Features of the computer system are an automated operation system and an open self-service system. Large-scale theoretical calculations have been performed to solve many problems in molecular science, using the computer system. Necessary conditions for future computers are discussed on the basis of this experience. (orig.)

  18. Nuclear power plant steam pipes repairing with Tirant 3 Robot system

    Energy Technology Data Exchange (ETDEWEB)

    Soto, M.; Curiel, M. [Logistica y Acondicionamientos Industriales SAU, Sorolla Center, local 10, Av. de las Cortes Valencianas No. 58, 46015 Valencia (Spain); Lazaro, F. [Revestimientos Anticorrosivos Industriales, S. L. U., Sorolla Center, local 10, Av. de las Cortes Valencianas No. 58, 46015 Valencia (Spain); Arnaldos, A., E-mail: m.soto@lainsa.co [TITANIA Servicios Tecnologicos SL, Sorolla Center, local 10, Av. de las Cortes Valencianas No. 58, 46015 Valencia (Spain)

    2010-10-15

    The metallization arc spray process is based on the projection of molten metal, supplied by means of different stainless alloys wire, over a surface of carbon steel usually, with the object of serving as protection against erosion-corrosion, increasing resistance to abrasion and detrition. A typical application functions covering the steam pipes inner surface in coal-fired power station and nuclear power plants. The results of this process are spectacular in terms of protection against corrosion and abrasion, but its application has conditioning factors, such as: Severe application conditions for workers. Due to the worker's postural position (usually kneeling) in 32 diameter pipes and working with fireproof clothing and masks with outdoor air supplying, due to fumes, sparks and molten metal particles, radiological contamination, confined space, poor lighting, ... Coating uniformity. As metallization is a manual process, the carried out measurements show small variations in the thickness of the coating, always within the tolerance limits established by the applicable regulations and quality assurance. An increase in the uniformity of the projected coating, increase the resistance and give a better surface protection. For all these reasons, Lainsa has developed the Tirant 3 robot, a worldwide innovative system, for metallization of steam pipes inner surface. Tirant 3 robot is tele operated from outside of the pipe, so that human intervention is reduced to the operations of robot positioning and change of metallization wire. As it is an independent system of the human factor, metallization process performance is significantly increased by reducing rest periods due only to the robot maintenance. Likewise, Tirant 3 system permits to increase resulting coating uniformity and thus its resistance, keeping selected parameters constant (forward speed, rotation speed and inner surface distance) depending on required type and thickness of wire. (Author)

  19. Availability allocation to repairable systems with genetic algorithms: a multi-objective formulation

    International Nuclear Information System (INIS)

    Elegbede, Charles; Adjallah, Kondo

    2003-01-01

    This paper describes a methodology based on genetic algorithms (GA) and experiments plan to optimize the availability and the cost of reparable parallel-series systems. It is a NP-hard problem of multi-objective combinatorial optimization, modeled with continuous and discrete variables. By using the weighting technique, the problem is transformed into a single-objective optimization problem whose constraints are then relaxed by the exterior penalty technique. We then propose a search of solution through GA, whose parameters are adjusted using experiments plan technique. A numerical example is used to assess the method

  20. Sensors Systems for the Automation of Operations in the Ship Repair Industry

    Science.gov (United States)

    Navarro, Pedro Javier; Muro, Juan Suardíaz; Alcover, Pedro María; Fernández-Isla, Carlos

    2013-01-01

    Hull cleaning before repainting is a key operation in the maintenance of ships. For years, a method to improve such operation has been sought by means of the robotization of techniques such as grit blasting and ultra high pressure water jetting. Despite this, it continues to be standard practice in shipyards that this process is carried out manually because the developed robotized systems are too expensive to be widely accepted by shipyards. We have chosen to apply a more conservative and realistic approach to this problem, which has resulted in the development of several solutions that have been designed with different automation and operation range degrees. These solutions are fitted with most of the elements already available in many shipyards, so the installation of additional machinery in the workplace would not be necessary. This paper describes the evolutionary development of sensor systems for the automation of the preparation process of ship hull surfaces before the painting process is performed. Such evolution has given rise to the development of new technologies for coating removal. PMID:24064601

  1. Drug-Loadable Calcium Alginate Hydrogel System for Use in Oral Bone Tissue Repair.

    Science.gov (United States)

    Chen, Luyuan; Shen, Renze; Komasa, Satoshi; Xue, Yanxiang; Jin, Bingyu; Hou, Yepo; Okazaki, Joji; Gao, Jie

    2017-05-06

    This study developed a drug-loadable hydrogel system with high plasticity and favorable biological properties to enhance oral bone tissue regeneration. Hydrogels of different calcium alginate concentrations were prepared. Their swelling ratio, degradation time, and bovine serum albumin (BSA) release rate were measured. Human periodontal ligament cells (hPDLCs) and bone marrow stromal cells (BMSCs) were cultured with both calcium alginate hydrogels and polylactic acid (PLA), and then we examined the proliferation of cells. Inflammatory-related factor gene expressions of hPDLCs and osteogenesis-related gene expressions of BMSCs were observed. Materials were implanted into the subcutaneous tissue of rabbits to determine the biosecurity properties of the materials. The materials were also implanted in mandibular bone defects and then scanned using micro-CT. The calcium alginate hydrogels caused less inflammation than the PLA. The number of mineralized nodules and the expression of osteoblast-related genes were significantly higher in the hydrogel group compared with the control group. When the materials were implanted in subcutaneous tissue, materials showed favorable biocompatibility. The calcium alginate hydrogels had superior osteoinductive bone ability to the PLA. The drug-loadable calcium alginate hydrogel system is a potential bone defect reparation material for clinical dental application.

  2. Brain aneurysm repair

    Science.gov (United States)

    ... aneurysm repair; Dissecting aneurysm repair; Endovascular aneurysm repair - brain; Subarachnoid hemorrhage - aneurysm ... Your scalp, skull, and the coverings of the brain are opened. A metal clip is placed at ...

  3. Molecular photoionization studies of nucleobases and correlated systems

    Energy Technology Data Exchange (ETDEWEB)

    Poliakoff, Erwin D. [Louisiana State Univ., Baton Rouge, LA (United States)

    2015-03-11

    We proposed molecular photoionization studies in order to probe correlated events in fundamental scattering phenomena. In particular, we suggested that joint theoretical-experimental studies would provide a window into the microscopic aspects that are of central importance in AMO and chemical physics generally, and would generate useful data for wide array of important DOE topics, such as ultrafast dynamics, high harmonic generation, and probes of nonadiabatic processes. The unifying theme is that correlations between electron scattering dynamics and molecular geometry highlight inherently molecular aspects of the photoelectron behavior.

  4. Repairing Canada’s Mining-Tax System to Be Less Distorting and Complex

    Directory of Open Access Journals (Sweden)

    Duanjie Chen

    2013-05-01

    Full Text Available The province of Ontario ended its most recent fiscal year with a $12 billion deficit and the Fraser Institute has calculated that the province is in worse financial shape than even the fiscally appalling state of California. One would think that a province so financially debilitated would want to avoid giving unnecessary and wasteful tax breaks to resource companies. Yet, a review of the mining-tax regimes across the country finds that Ontario’s system — specifically its provincial resource allowance, which duplicates the allowances provided by Ottawa that shield miners from risk — is redundant, expensive and wasteful. Ontario is not the only province requiring a modernization of its mining-tax regime. In every province except Nova Scotia and New Brunswick, mining firms enjoy a lower marginal rate for taxes and royalties than for non-resource companies. The inevitable result has been a distortion of investment toward mining projects that might otherwise be economically inefficient. That means that in major oil-producing provinces, such as Alberta, Saskatchewan and Newfoundland, mining investment benefits from larger tax incentives than oil and gas investment. The reasons for favouring the mining of metal over oil are at least unclear and certainly economically unjustifiable. The federal government has already begun making several changes to its tax policies to scale back preferential and irrational inducements for mining investment, including, most recently, reducing accelerated depreciation allowances for certain mining assets and phasing out the corporate Mineral Exploration Tax Credit and the Atlantic Investment Tax Credit for resources. But Ottawa’s efforts to modernize Canada’s mining-tax structure can only go so far, when provinces continue to rely on what are often overly complex tax systems that have a distortionary effect on economic decisions being made by investors. The next step in modernizing Canada’s mining-tax system

  5. GLI1 interferes with the DNA mismatch repair system in pancreatic cancer through BHLHE41-mediated suppression of MLH1.

    Science.gov (United States)

    Inaguma, Shingo; Riku, Miho; Hashimoto, Mitsuyoshi; Murakami, Hideki; Saga, Shinsuke; Ikeda, Hiroshi; Kasai, Kenji

    2013-12-15

    The mismatch repair (MMR) system is indispensable for the fidelity of DNA replication, the impairment of which predisposes to the development and progression of many types of cancers. To date, GLI1 transcription factor, a key molecule of the Hedgehog signaling pathway, has been shown to regulate the expression of several genes crucial for a variety of cancer cell properties in many types of cancers, including pancreatic ductal adenocarcinoma (PDAC), but whether GLI1 could control the MMR system was not known. Here, we showed that GLI1 and GLI2 indirectly suppressed the expression of MLH1 in PDAC cells. Through GLI1 target gene screening, we found that GLI1 and GLI2 activated the expression of a basic helix-loop-helix type suppressor BHLHE41/DEC2/SHARP1 through a GLI-binding site in the promoter. Consistent with a previous report that BHLHE41 suppresses the MLH1 promoter activity, we found that the activation of GLI1 led to the BHLHE41-dependent suppression of MLH1, and a double knockdown of GLI1 and GLI2 conversely increased the MLH1 protein in PDAC cells. Using TALEN-based modification of the MLH1 gene, we further showed that GLI1 expression was indeed associated with an increased tolerance to a methylating agent, methylnitrosourea cooperatively with a lower copy number status of MLH1. Finally, GLI1 expression was immunohistochemically related positively with BHLHE41 and inversely with MLH1 in PDAC cells and precancerous lesions of the pancreas. On the basis of these results, we propose that GLI1 depresses the MMR activity and might contribute to the development and progression of PDAC. ©2013 AACR.

  6. Diffracted X-ray tracking: new system for single molecular detection with X-rays

    CERN Document Server

    Sasaki, Y C; Adachi, S; Suzuki, Y; Yagi, N

    2001-01-01

    We propose a new X-ray methodology for direct observations of the behaviors of single molecular units in real time and real space. This new system, which we call Diffracted X-ray Tracking (DXT), monitors the Brownian motions of a single molecular unit by observations of X-ray diffracted spots from a nanocrystal, tightly bound to the individual single molecular unit in bio-systems. DXT does not determine any translational movements, but only orientational movements.

  7. Diffracted X-ray tracking: new system for single molecular detection with X-rays

    International Nuclear Information System (INIS)

    Sasaki, Y.C.; Okumura, Y.; Adachi, S.; Suzuki, Y.; Yagi, N.

    2001-01-01

    We propose a new X-ray methodology for direct observations of the behaviors of single molecular units in real time and real space. This new system, which we call Diffracted X-ray Tracking (DXT), monitors the Brownian motions of a single molecular unit by observations of X-ray diffracted spots from a nanocrystal, tightly bound to the individual single molecular unit in bio-systems. DXT does not determine any translational movements, but only orientational movements

  8. Molecular Genetic and Gene Therapy Studies of the Musculoskeletal System

    National Research Council Canada - National Science Library

    Baylink, David

    2004-01-01

    The primary goal of the proposed work is to apply several state of the art molecular genetic and gene therapy technologies to address fundamental questions in bone biology with a particular emphasis on attempting: l...

  9. Nanowired Drug Delivery Across the Blood-Brain Barrier in Central Nervous System Injury and Repair.

    Science.gov (United States)

    Sharma, Aruna; Menon, Preeti; Muresanu, Dafin F; Ozkizilcik, Asya; Tian, Z Ryan; Lafuente, José V; Sharma, Hari S

    2016-01-01

    The blood-brain barrier (BBB) is a physiological regulator of transport of essential items from blood to brain for the maintenance of homeostasis of the central nervous system (CNS) within narrow limits. The BBB is also responsible for export of harmful or metabolic products from brain to blood to keep the CNS fluid microenvironment healthy. However, noxious insults to the brain caused by trauma, ischemia or environmental/chemical toxins alter the BBB function to small as well as large molecules e.g., proteins. When proteins enter the CNS fluid microenvironment, development of brain edema occurs due to altered osmotic balance between blood and brain. On the other hand, almost all neurodegenerative diseases and traumatic insults to the CNS and subsequent BBB dysfunction lead to edema formation and cell injury. To treat these brain disorders suitable drug therapy reaching their brain targets is needed. However, due to edema formation or only a focal disruption of the BBB e.g., around brain tumors, many drugs are unable to reach their CNS targets in sufficient quantity. This results in poor therapeutic outcome. Thus, new technology such as nanodelivery is needed for drugs to reach their CNS targets and be effective. In this review, use of nanowires as a possible novel tool to enhance drug delivery into the CNS in various disease models is discussed based on our investigations. These data show that nanowired delivery of drugs may have superior neuroprotective ability to treat several CNS diseases effectively indicating their role in future therapeutic strategies.

  10. Pelvic organ prolapse repair using the Uphold™ Vaginal Support System: a 1-year multicenter study.

    Science.gov (United States)

    Altman, Daniel; Mikkola, Tomi S; Bek, Karl Möller; Rahkola-Soisalo, Päivi; Gunnarsson, Jonas; Engh, Marie Ellström; Falconer, Christian

    2016-09-01

    The objective was to assess safety and clinical outcomes in women operated on using the Uphold™ Lite Vaginal Support System. We carried out a 1-year, multicenter, prospective, single cohort study of 207 women with symptomatic Pelvic Organ Prolapse Quantification (POP-Q) stage ≥2 apical pelvic organ prolapse, with or without concomitant anterior vaginal wall prolapse. Safety data were collected using a standardized questionnaire. Anatomical outcome was assessed by the POP-Q and subjective outcomes by the Pelvic Floor Distress Inventory after 2 months and 1 year using a one-way repeated measures analysis of variance. Pain was evaluated using a visual analog scale. The overall rate of serious complications was 4.3 % (9 out of 207 patients), including 3 patients with bladder perforations, 1 with bleeding >1,000 ml, 2 who had undergone re-operations with complete mesh removal because of pain, and 3 surgical interventions during follow-up because of mesh exposure. POP-Q stage ≤1 after 1 year was 94 % and subjective symptom relief was reported by 91 % of patients (p transvaginal mesh kits.

  11. Extracellular Matrix (ECM) Multilayer Membrane as a Sustained Releasing Growth Factor Delivery System for rhTGF-β3 in Articular Cartilage Repair

    Science.gov (United States)

    Park, Sang-Hyug; Kim, Moon Suk; Kim, Young Jick; Choi, Byung Hyune; Lee, Chun Tek; Park, So Ra; Min, Byoung-Hyun

    2016-01-01

    Recombinant human transforming growth factor beta-3 (rhTGF-β3) is a key regulator of chondrogenesis in stem cells and cartilage formation. We have developed a novel drug delivery system that continuously releases rhTGF-β3 using a multilayered extracellular matrix (ECM) membrane. We hypothesize that the sustained release of rhTGF-β3 could activate stem cells and result in enhanced repair of cartilage defects. The properties and efficacy of the ECM multilayer-based delivery system (EMLDS) are investigated using rhTGF-β3 as a candidate drug. The bioactivity of the released rhTGF-ß3 was evaluated through chondrogenic differentiation of mesenchymal stem cells (MSCs) using western blot and circular dichroism (CD) analyses in vitro. The cartilage reparability was evaluated through implanting EMLDS with endogenous and exogenous MSC in both in vivo and ex vivo models, respectively. In the results, the sustained release of rhTGF-ß3 was clearly observed over a prolonged period of time in vitro and the released rhTGF-β3 maintained its structural stability and biological activity. Successful cartilage repair was also demonstrated when rabbit MSCs were treated with rhTGF-β3-loaded EMLDS ((+) rhTGF-β3 EMLDS) in an in vivo model and when rabbit chondrocytes and MSCs were treated in ex vivo models. Therefore, the multilayer ECM membrane could be a useful drug delivery system for cartilage repair. PMID:27258120

  12. Extracellular Matrix (ECM Multilayer Membrane as a Sustained Releasing Growth Factor Delivery System for rhTGF-β3 in Articular Cartilage Repair.

    Directory of Open Access Journals (Sweden)

    Soon Sim Yang

    Full Text Available Recombinant human transforming growth factor beta-3 (rhTGF-β3 is a key regulator of chondrogenesis in stem cells and cartilage formation. We have developed a novel drug delivery system that continuously releases rhTGF-β3 using a multilayered extracellular matrix (ECM membrane. We hypothesize that the sustained release of rhTGF-β3 could activate stem cells and result in enhanced repair of cartilage defects. The properties and efficacy of the ECM multilayer-based delivery system (EMLDS are investigated using rhTGF-β3 as a candidate drug. The bioactivity of the released rhTGF-ß3 was evaluated through chondrogenic differentiation of mesenchymal stem cells (MSCs using western blot and circular dichroism (CD analyses in vitro. The cartilage reparability was evaluated through implanting EMLDS with endogenous and exogenous MSC in both in vivo and ex vivo models, respectively. In the results, the sustained release of rhTGF-ß3 was clearly observed over a prolonged period of time in vitro and the released rhTGF-β3 maintained its structural stability and biological activity. Successful cartilage repair was also demonstrated when rabbit MSCs were treated with rhTGF-β3-loaded EMLDS ((+ rhTGF-β3 EMLDS in an in vivo model and when rabbit chondrocytes and MSCs were treated in ex vivo models. Therefore, the multilayer ECM membrane could be a useful drug delivery system for cartilage repair.

  13. DNA repair , cell repair and radiosensitivity

    International Nuclear Information System (INIS)

    Zhestyanikov, V.D.

    1983-01-01

    Data obtained in laboratory of radiation cytology and literature data testifying to a considerable role of DNA repair in cell sensitivity to radiation and chemical DNA-tropic agents have been considered. Data pointing to the probability of contribution of inducible repair of DNA into plant cells sensitivity to X-rays are obtained. Certain violations of DNA repair do not result in the increase of radiosensitivity. It is assumed that in the cases unknown mechanisms of DNA repair operate

  14. Effect of Mercuric Nitrate on Repair of Radiation-induced DNA Damage

    Energy Technology Data Exchange (ETDEWEB)

    Paneka, Agnieszka; Antonina, Cebulska Wasilewska [The Henryk Niewodniczanski Institute of Nuclear Physics, Krakow (Poland); Han, Min; Kim, Jin Kyu [Korea Atomic Energy Research Institute, Jeongeup (Korea, Republic of)

    2009-10-15

    High concentrations of mercury can cause serious damage to the nervous system, immune system, kidneys and liver in humans. And mercury is toxic to developing embryos because mercury ions can penetrate the blood.placenta barrier to reach the embryo. Studies from human monitoring of occupational exposure to mercury vapours have shown that mercury can alter the ability of lymphocytes to repair radiation-induced DNA damage. The aim of this in vitro study was to investigate, on the molecular and cytogenetic levels, the effect of exposure to mercury ions on the kinetics of the repair process of DNA damage induced by ionising radiation.

  15. Efficacy and safety of Elevate® system on apical and anterior compartment prolapse repair with personal technique modification

    Directory of Open Access Journals (Sweden)

    Daniele Castellani

    Full Text Available ABSTRACT Aim: To evaluate the effectiveness and safety of Anterior Elevate® mesh kit system (AES in woman with symptomatic stage 3 or 4 anterior and/or apical pelvic organ prolapse (POP. Materials and Methods: This retrospective, monocentric, single surgeon study enrolled between May 2010 and January 2013 fifty-six woman experiencing symptomatic anterior vaginal prolapse with or without apical descent (POP-Q stage 3 or 4. All women received a AES and 7 (12.5% received a concomitant transvaginal hysterectomy. Primary endpoint was anatomic correction of prolapse; success was defined as POP-Q stage ≤ 1 or asymptomatic stage 2. Secondary endpoints were quality-of-life (QOL results and patients' safety outcomes, which were assessed by 3 validated self-reporting questionnaires at baseline and annually: ICIQ-UI short form, ICIQ-VS and P-QOL. All patients completed 2-years and 28 women 3-years of follow-up. Surgical approach was modified in women with uterus, moving the two-propylene strips anteriorly around the cervix itself crossing one another, so the left will take place in the right side and the right on the opposite. This modification was made in order to better support the uterus. Results: Vaginal mesh exposure was present in 3 (5,3% patients. Very good anatomical outcomes were seen, with one (1,8% failure at 6-months, 4 (7,1% at 1-year, 6 at 2-years (10,7%. Statistically significant improvements were seen in the ICIQ-VS and P-QOL questionnaires throughout follow-up. Conclusion: Our data suggest that AES is a minimally-invasive transvaginal procedure to repair anterior and apical POP, with good evidence related to mid-term safety and efficacy.

  16. Design and preliminary validation of a mobile application-based expert system to facilitate repair of medical equipment in resource-limited health settings

    Directory of Open Access Journals (Sweden)

    Wong AL

    2018-05-01

    Full Text Available Alison L Wong,1,2 Kelly M Lacob,1 Madeline G Wilson,1 Stacie M Zwolski,1 Soumyadipta Acharya1 1Center for Bioengineering, Innovation and Design, Johns Hopkins University, Baltimore, MD, USA; 2Division of Plastic Surgery, Dalhousie University, Halifax, NS, Canada Background: One of the greatest barriers to safe surgery is the availability of functional biomedical equipment. Biomedical technicians play a major role in ensuring that equipment is functional. Following in-field observations and an online survey, a mobile application was developed to aid technicians in troubleshooting biomedical equipment. It was hypothesized that this application could be used to aid technicians in equipment repair, as modeled by repair of a pulse oximeter.Methods: To identify specific barriers to equipment repair and maintenance for biomedical technicians, an online survey was conducted to determine current practices and challenges. These findings were used to guide the development of a mobile application system that guides technicians through maintenance and repair tasks. A convenience sample of technicians in Ethiopia tested the application using a broken pulse oximeter task and following this completed usability and content validity surveys.Results: Fifty-three technicians from 13 countries responded to the initial survey. The results of the survey showed that technicians find equipment manuals most useful, but these are not easily accessible. Many do not know how to or are uncomfortable reaching out to human resources. Thirty-three technicians completed the broken pulse oximeter task using the application. All were able to appropriately identify and repair the equipment, and post-task surveys of usability and content validity demonstrated highly positive scores (Agree to Strongly Agree on both scales.Discussion: This research demonstrates the need for improved access to resources for technicians and shows that a mobile application can be used to address a gap in

  17. UV radiation in marine ectotherms: Molecular effects and responses

    International Nuclear Information System (INIS)

    Dahms, Hans-U.; Lee, Jae-Seong

    2010-01-01

    This review summarizes current knowledge on ultraviolet radiation (UVR)-induced cellular and molecular damage in marine ectotherms (invertebrates and fish). UVR impairs sperm motility, reduces fertilization, and causes embryo malformation that in turn affects recruitment and therefore the sustainability of natural populations. The direct molecular effects of UVR are mediated by absorption of certain wavelengths by specific macromolecules and the dissipation of the absorbed energy via photochemical reactions. Most organisms have defense mechanisms that either prevent UVR-induced damage, or mechanisms that repair the damage. Photoprotective pigments, antioxidant defense compounds, and cell cycle development genes are some of the molecules involved in UVR defense. Photoenzymatic repair and nucleotide excision repair are the two primary DNA repair systems in marine ectotherms. We anticipate that toxicogenomic studies will gain importance in UVR research because they can elucidate the primary processes involved in UVR damage and the cellular response to this damage.

  18. Ion-molecular equilibria and activity determination in the RbF-ZrF4 system

    International Nuclear Information System (INIS)

    Skokan, E.V.; Nikitin, M.I.; Sorokin, I.D.; Korenev, Yu.M.; Sidorov, L.N.

    1983-01-01

    Activity of zirconium tetrofluoride in 100-33.3 mol % ZrF 4 concentration range was determined during isothermal evaporation of samples of different initial composition of RbF-ZrF 4 system, using ion-molecular equilibrium method. It became possible, using the exchange ion-molecular reactions to determine ZrF 4 activity approximately 10 -10 in the region of state diagram of RbF-ZrF 4 system, adjoining to rubidium fluoride. The comparative analysis of results, obtained by the methods of isothermal evaporation, ion-molecular equilibria is given; the advantages and restrictions of ion-molecular equilibrium method are presented

  19. Repair of potentially lethal damage following irradiation with x rays or cyclotron neutrons: response of the EMT-6/UW tumor system treated under various growth conditions in vitro and in vivo

    International Nuclear Information System (INIS)

    Rasey, J.S.; Nelson, N.J.

    1981-01-01

    Postirradiation potentially lethal damage (PLD) repair was examined in the EMT-6/UW tumor system under a variety of in vitro and in vivo growth conditions. Following x irradiation, surviving fraction increased in fed and unfed plateau cultures if subculture and plating were delayed; in exponentially growing cultures if they were covered with depleted medium for the first 6 h postirradiation; and in tumors in vivo if excision for preparation of a cell suspension was delayed. Following irradiation with 21.5 meV (d + → Be) neutrons, PLD repair was measurable only in unfed plateau cultures when subculture was delayed and in exponentially growing cells exposed to depleted culture medium immediately after irradiation. In x-irradiated EMT-6/UW cells, the greatest repair capacity and the highest surviving fraction ratios were measured in unfed plateau cultures; the least repair was observed in exponentially growing cells exposed to depleted medium. Thus post-neutron repair was not limited to situations where the amount of repair of photon PLD is large. The demonstration of PLD repair in tumors irradiated in vivo with X rays and the absence of such repair after neutrons could have important implications in radiotherapy if this is a general phenomenon

  20. On a Batch Arrival Queuing System Equipped with a Stand-by Server during Vacation Periods or the Repairs Times of the Main Server

    Directory of Open Access Journals (Sweden)

    Rehab F. Khalaf

    2011-01-01

    Full Text Available We study a queuing system which is equipped with a stand-by server in addition to the main server. The stand-by server provides service to customers only during the period of absence of the main server when either the main server is on a vacation or it is in the state of repairs due to a sudden failure from time to time. The service times, vacation times, and repair times are assumed to follow general arbitrary distributions while the stand-by service times follow exponential distribution. Supplementary variables technique has been used to obtain steady state results in explicit and closed form in terms of the probability generating functions for the number of customers in the queue, the average number of customers, and the average waiting time in the queue while the MathCad software has been used to illustrate the numerical results in this work.

  1. Protective Effect of Diphlorethohydroxycarmalol against Ultraviolet B Radiation-Induced DNA Damage by Inducing the Nucleotide Excision Repair System in HaCaT Human Keratinocytes

    Directory of Open Access Journals (Sweden)

    Mei Jing Piao

    2015-09-01

    Full Text Available We investigated the protective properties of diphlorethohydroxycarmalol (DPHC, a phlorotannin, against ultraviolet B (UVB radiation-induced cyclobutane pyrimidine dimers (CPDs in HaCaT human keratinocytes. The nucleotide excision repair (NER system is the pathway by which cells identify and repair bulky, helix-distorting DNA lesions such as ultraviolet (UV radiation-induced CPDs and 6-4 photoproducts. CPDs levels were elevated in UVB-exposed cells; however, this increase was reduced by DPHC. Expression levels of xeroderma pigmentosum complementation group C (XPC and excision repair cross-complementing 1 (ERCC1, which are essential components of the NER pathway, were induced in DPHC-treated cells. Expression of XPC and ERCC1 were reduced following UVB exposure, whereas DPHC treatment partially restored the levels of both proteins. DPHC also increased expression of transcription factor specificity protein 1 (SP1 and sirtuin 1, an up-regulator of XPC, in UVB-exposed cells. DPHC restored binding of the SP1 to the XPC promoter, which is reduced in UVB-exposed cells. These results indicate that DPHC can protect cells against UVB-induced DNA damage by inducing the NER system.

  2. Optimization of fuel ethanol recovery systems using molecular sieves

    International Nuclear Information System (INIS)

    Scheller, W.A.

    1989-01-01

    The use of molecular sieves for the dehydration of rectified fuel ethanol requires only about 58% of the energy required by azeotropic distillation, the usual commercial process. Recently molecular sieve prices have become low enough that their use can be economically competitive with azeotropic distillation. This paper contains results of mass and energy balances to determine the water content of the rectified ethanol (6.15 weight percent) that will result in the minimum energy requirement for producing anhydrous ethanol with the molecular sieve process and byproduct distillers soluble syrup from fermented corn mash containing 7.23 weight percent ethanol. In this paper results of economic evaluations to determine the water content of the rectified ethanol (7.58 weight percent) which results in a minimum investment and operating cost are presented

  3. Subtle Monte Carlo Updates in Dense Molecular Systems

    DEFF Research Database (Denmark)

    Bottaro, Sandro; Boomsma, Wouter; Johansson, Kristoffer E.

    2012-01-01

    Although Markov chain Monte Carlo (MC) simulation is a potentially powerful approach for exploring conformational space, it has been unable to compete with molecular dynamics (MD) in the analysis of high density structural states, such as the native state of globular proteins. Here, we introduce...... as correlations in a multivariate Gaussian distribution. We demonstrate that our method reproduces structural variation in proteins with greater efficiency than current state-of-the-art Monte Carlo methods and has real-time simulation performance on par with molecular dynamics simulations. The presented results...... suggest our method as a valuable tool in the study of molecules in atomic detail, offering a potential alternative to molecular dynamics for probing long time-scale conformational transitions....

  4. Ins and outs of systems biology vis-à-vis molecular biology: continuation or clear cut?

    Science.gov (United States)

    De Backer, Philippe; De Waele, Danny; Van Speybroeck, Linda

    2010-03-01

    The comprehension of living organisms in all their complexity poses a major challenge to the biological sciences. Recently, systems biology has been proposed as a new candidate in the development of such a comprehension. The main objective of this paper is to address what systems biology is and how it is practised. To this end, the basic tools of a systems biological approach are explored and illustrated. In addition, it is questioned whether systems biology 'revolutionizes' molecular biology and 'transcends' its assumed reductionism. The strength of this claim appears to depend on how molecular and systems biology are characterised and on how reductionism is interpreted. Doing credit to molecular biology and to methodological reductionism, it is argued that the distinction between molecular and systems biology is gradual rather than sharp. As such, the classical challenge in biology to manage, interpret and integrate biological data into functional wholes is further intensified by systems biology's use of modelling and bioinformatics, and by its scale enlargement.

  5. DNA repair in Mycobacterium tuberculosis revisited.

    Science.gov (United States)

    Dos Vultos, Tiago; Mestre, Olga; Tonjum, Tone; Gicquel, Brigitte

    2009-05-01

    Our understanding of Mycobacterium tuberculosis DNA repair mechanisms is still poor compared with that of other bacterial organisms. However, the publication of the first complete M. tuberculosis genome sequence 10 years ago boosted the study of DNA repair systems in this organism. A first step in the elucidation of M. tuberculosis DNA repair mechanisms was taken by Mizrahi and Andersen, who identified homologs of genes involved in the reversal or repair of DNA damage in Escherichia coli and related organisms. Genes required for nucleotide excision repair, base excision repair, recombination, and SOS repair and mutagenesis were identified. Notably, no homologs of genes involved in mismatch repair were identified. Novel characteristics of the M. tuberculosis DNA repair machinery have been found over the last decade, such as nonhomologous end joining, the presence of Mpg, ERCC3 and Hlr - proteins previously presumed to be produced exclusively in mammalian cells - and the recently discovered bifunctional dCTP deaminase:dUTPase. The study of these systems is important to develop therapeutic agents that can counteract M. tuberculosis evolutionary changes and to prevent adaptive events resulting in antibiotic resistance. This review summarizes our current understanding of the M. tuberculosis DNA repair system.

  6. High levels of BRC4 induced by a Tet-On 3G system suppress DNA repair and impair cell proliferation in vertebrate cells.

    Science.gov (United States)

    Abe, Takuya; Branzei, Dana

    2014-10-01

    Transient induction or suppression of target genes is useful to study the function of toxic or essential genes in cells. Here we apply a Tet-On 3G system to DT40 lymphoma B cell lines, validating it for three different genes. Using this tool, we then show that overexpression of the chicken BRC4 repeat of the tumor suppressor BRCA2 impairs cell proliferation and induces chromosomal breaks. Mechanistically, high levels of BRC4 suppress double strand break-induced homologous recombination, inhibit the formation of RAD51 recombination repair foci, reduce cellular resistance to DNA damaging agents and induce a G2 damage checkpoint-mediated cell-cycle arrest. The above phenotypes are mediated by BRC4 capability to bind and inhibit RAD51. The toxicity associated with BRC4 overexpression is exacerbated by chemotherapeutic agents and reversed by RAD51 overexpression, but it is neither aggravated nor suppressed by a deficit in the non-homologous end-joining pathway of double strand break repair. We further find that the endogenous BRCA2 mediates the cytotoxicity associated with BRC4 induction, thus underscoring the possibility that BRC4 or other domains of BRCA2 cooperate with ectopic BRC4 in regulating repair activities or mitotic cell division. In all, the results demonstrate the utility of the Tet-On 3G system in DT40 research and underpin a model in which BRC4 role on cell proliferation and chromosome repair arises primarily from its suppressive role on RAD51 functions. Copyright © 2014 The Authors. Published by Elsevier B.V. All rights reserved.

  7. Molecular profiles to biology and pathways: a systems biology approach.

    Science.gov (United States)

    Van Laere, Steven; Dirix, Luc; Vermeulen, Peter

    2016-06-16

    Interpreting molecular profiles in a biological context requires specialized analysis strategies. Initially, lists of relevant genes were screened to identify enriched concepts associated with pathways or specific molecular processes. However, the shortcoming of interpreting gene lists by using predefined sets of genes has resulted in the development of novel methods that heavily rely on network-based concepts. These algorithms have the advantage that they allow a more holistic view of the signaling properties of the condition under study as well as that they are suitable for integrating different data types like gene expression, gene mutation, and even histological parameters.

  8. FROM ATOMISTIC TO SYSTEMATIC COARSE-GRAINED MODELS FOR MOLECULAR SYSTEMS

    KAUST Repository

    Harmandaris, Vagelis

    2017-10-03

    The development of systematic (rigorous) coarse-grained mesoscopic models for complex molecular systems is an intense research area. Here we first give an overview of methods for obtaining optimal parametrized coarse-grained models, starting from detailed atomistic representation for high dimensional molecular systems. Different methods are described based on (a) structural properties (inverse Boltzmann approaches), (b) forces (force matching), and (c) path-space information (relative entropy). Next, we present a detailed investigation concerning the application of these methods in systems under equilibrium and non-equilibrium conditions. Finally, we present results from the application of these methods to model molecular systems.

  9. Environmental Molecular Sciences Laboratory Operations System: Version 4.0 - system requirements specification

    Energy Technology Data Exchange (ETDEWEB)

    Kashporenko, D.

    1996-07-01

    This document is intended to provide an operations standard for the Environmental Molecular Sciences Laboratory OPerations System (EMSL OPS). It is directed toward three primary audiences: (1) Environmental Molecular Sciences Laboratory (EMSL) facility and operations personnel; (2) laboratory line managers and staff; and (3) researchers, equipment operators, and laboratory users. It is also a statement of system requirements for software developers of EMSL OPS. The need for a finely tuned, superior research environment as provided by the US Department of Energy`s (DOE) Environmental Molecular Sciences Laboratory has never been greater. The abrupt end of the Cold War and the realignment of national priorities caused major US and competing overseas laboratories to reposition themselves in a highly competitive research marketplace. For a new laboratory such as the EMSL, this means coming into existence in a rapidly changing external environment. For any major laboratory, these changes create funding uncertainties and increasing global competition along with concomitant demands for higher standards of research product quality and innovation. While more laboratories are chasing fewer funding dollars, research ideas and proposals, especially for molecular-level research in the materials and biological sciences, are burgeoning. In such an economically constrained atmosphere, reduced costs, improved productivity, and strategic research project portfolio building become essential to establish and maintain any distinct competitive advantage. For EMSL, this environment and these demands require clear operational objectives, specific goals, and a well-crafted strategy. Specific goals will evolve and change with the evolution of the nature and definition of DOE`s environmental research needs. Hence, EMSL OPS is designed to facilitate migration of these changes with ease into every pertinent job function, creating a facile {open_quotes}learning organization.{close_quotes}

  10. Molecular materials and devices: developing new functional systems based on the coordination chemistry approach

    Directory of Open Access Journals (Sweden)

    Toma Henrique E.

    2003-01-01

    Full Text Available At the onset of the nanotechnology age, molecular designing of materials and single molecule studies are opening wide possibilities of using molecular systems in electronic and photonic devices, as well as in technological applications based on molecular switching or molecular recognition. In this sense, inorganic chemists are privileged by the possibility of using the basic strategies of coordination chemistry to build up functional supramolecular materials, conveying the remarkable chemical properties of the metal centers and the characteristics of the ancillary ligands. Coordination chemistry also provides effective self-assembly strategies based on specific metal-ligand affinity and stereochemistry. Several molecular based materials, derived from inorganic and metal-organic compounds are focused on this article, with emphasis on new supramolecular porphyrins and porphyrazines, metal-clusters and metal-polyimine complexes. Such systems are also discussed in terms of their applications in catalysis, sensors and molecular devices.

  11. Development of diagnosis and repair system for steelmaking refractories; Seikoyo taikabutsu no shindan hoshu gijutsu no kakuritsu

    Energy Technology Data Exchange (ETDEWEB)

    Aso, S.; Harada, S.; Tsutsui, Y. [Nippon Steel Corp., Tokyo (Japan)

    1996-06-01

    The latest measurement equipment and repair method were introduced into the work area of all refractories in the process of torpedo cars, hot metal preliminary treatment, hot metal pans, secondary refining, and cast pans so as to improve the cost of the newest advanced steelmaking refractories. As a result, the refractory cost could be reduced by 10%. This paper introduces the improvement in RH refractories and refractories for hot metal preliminary treatment. As for basic items, in addition to the visual observation, the thickness of refractories was quantified using equipment (laser profile meter, thermotracer, and NS sensor) for the furnace stop in the minimum remaining length. An ITV was also installed in the facilities where the visual check is difficult to carry out. Repair is mainly done by spraying. A thermal spraying repair method with high durability was used for the repair. A method that relieves a thermal shock was used for preheating. Moreover, measures that make the temperature gradient in the thickness direction uniform by using newly developed microwave drying equipment were taken for drying of unburned refractories. 4 refs., 13 figs., 2 tabs.

  12. Assessment of DNA damage and repair in Mycobacterium terrae after exposure to UV irradiation.

    Science.gov (United States)

    Bohrerova, Z; Linden, K G

    2006-11-01

    Ultraviolet (UV) irradiation for drinking water treatment was examined for inactivation and subsequent dark and photo-repair of Mycobacterium terrae. UV sources tested were low pressure (monochromatic, 254 nm) and medium pressure (polychromatic UV output) Hg lamps. UV exposure resulted in inactivation, and was followed by dark or photo-repair experiments. Inactivation and repair were quantified utilizing a molecular-based endonuclease sensitive site (ESS) assay and conventional colony forming unit (CFU) viability assay. Mycobacterium terrae was more resistant to UV disinfection compared to many other bacteria, with approximately 2-log reduction at a UV fluence of 10 mJ cm(-2) ; similar to UV inactivation of M. tuberculosis. There was no difference in inactivation between monochromatic or polychromatic UV lamps. Mycobacterium terrae did not undergo detectable dark repair. Photo-repair resulted in recovery from inactivation by approximately 0.5-log in less than 30 min for both UV lamp systems. Mycobacterium terrae is able to photo-repair DNA damage within a short timeframe. The number of pyrimidine dimers induced by UV light were similar for Escherichia coli and M. terrae, however, this similarity did not hold true for viability results. There is no practical difference between UV sources for disinfection or prevention of DNA repair for M. terrae. The capability of M. terrae to photo-repair UV damage fairly quickly is important for wastewater treatment applications where disinfected effluent is exposed to sunlight. Finally, molecular based assay results should be evaluated with respect to differences in the nucleic acid content of the test micro-organism.

  13. Electrochemistry of single molecules and biomolecules, molecular scale nanostructures, and low-dimensional systems

    DEFF Research Database (Denmark)

    Nazmutdinov, Renat R.; Zinkicheva, Tamara T.; Zinkicheva, Tamara T.

    2018-01-01

    Electrochemistry at ultra-small scales, where even the single molecule or biomolecule can be characterized and manipulated, is on the way to a consolidated status. At the same time molecular electrochemistry is expanding into other areas of sophisticated nano- and molecular scale systems includin...... molecular scale metal and semiconductor nanoparticles (NPs) and other nanostructures, e.g. nanotubes, “nanoflowers” etc.. The new structures offer both new electronic properties and highly confined novel charge transfer environments....

  14. The Physics of Coupled Atomic-Molecular Condensate System

    Science.gov (United States)

    2010-10-09

    electric dipoles represents a novel state of matter with long-range and anisotropic dipole-dipole interactions, that are highly amenable to the...free-bound FC factor. Simultaneously, a series of laser �elds of (molecular) Rabi frequency i (i 2) are applied to move the molecules from the

  15. Role of glutathione in affecting the radiosensitivity of molecular and cellular systems

    International Nuclear Information System (INIS)

    Simone, G.; Tamba, M.; Quintiliani, M.

    1983-01-01

    It has previously been shown that radioinduced organic radicals can be repaired by hydrogen donation from glutathione (GSH) and this repair is in competition with oxygen (damage fixation). In this paper the influence of exogenous glutathione on the radiation response of the enzyme alcoholdehydrogenase (YADH), DNA in vitro, and E. coli B/r cells has been investigated. GSH is observed to protect YADH essentially by free radical scavenging mechanisms in both presence or absence of oxygen. The same mechanism seems operate in the radioprotection afforded by GSH to DNA in vitro. E. coli B/r cells are protected at higher extent by GSH than its oxidized form (GSSG); the possibility that GSH penetrate into bacterial cells more easily that GSSG can explain their different behaviour. None of the three systems studied has provided definitive support for the occurrence of the hydrogen donation reaction in the radioprotective mechanisms of GSH versus biomolecules and bacterial cells. (orig.)

  16. Integration of Principles of Systems Biology and Radiation Biology: Toward Development of in silico Models to Optimize IUdR-Mediated Radiosensitization of DNA Mismatch Repair Deficient (Damage Tolerant) Human Cancers

    International Nuclear Information System (INIS)

    Kinsella, Timothy J.; Gurkan-Cavusoglu, Evren; Du, Weinan; Loparo, Kenneth A.

    2011-01-01

    Over the last 7 years, we have focused our experimental and computational research efforts on improving our understanding of the biochemical, molecular, and cellular processing of iododeoxyuridine (IUdR) and ionizing radiation (IR) induced DNA base damage by DNA mismatch repair (MMR). These coordinated research efforts, sponsored by the National Cancer Institute Integrative Cancer Biology Program (ICBP), brought together system scientists with expertise in engineering, mathematics, and complex systems theory and translational cancer researchers with expertise in radiation biology. Our overall goal was to begin to develop computational models of IUdR- and/or IR-induced base damage processing by MMR that may provide new clinical strategies to optimize IUdR-mediated radiosensitization in MMR deficient (MMR − ) “damage tolerant” human cancers. Using multiple scales of experimental testing, ranging from purified protein systems to in vitro (cellular) and to in vivo (human tumor xenografts in athymic mice) models, we have begun to integrate and interpolate these experimental data with hybrid stochastic biochemical models of MMR damage processing and probabilistic cell cycle regulation models through a systems biology approach. In this article, we highlight the results and current status of our integration of radiation biology approaches and computational modeling to enhance IUdR-mediated radiosensitization in MMR − damage tolerant cancers.

  17. Application of nonhomogeneous Poisson process to reliability analysis of repairable systems of a nuclear power plant with rates of occurrence of failures time-dependent

    International Nuclear Information System (INIS)

    Saldanha, Pedro L.C.; Simone, Elaine A. de; Melo, Paulo Fernando F.F. e

    1996-01-01

    Aging is used to mean the continuous process which physical characteristics of a system, a structure or an equipment changes with time or use. Their effects are increases in failure probabilities of a system, a structure or an equipment, and their are calculated using time-dependent failure rate models. The purpose of this paper is to present an application of the nonhomogeneous Poisson process as a model to study rates of occurrence of failures when they are time-dependent. To this application, an analysis of reliability of service water pumps of a typical nuclear power plant is made, as long as the pumps are effectively repaired components. (author)

  18. Integrative pathway knowledge bases as a tool for systems molecular medicine.

    Science.gov (United States)

    Liang, Mingyu

    2007-08-20

    There exists a sense of urgency to begin to generate a cohesive assembly of biomedical knowledge as the pace of knowledge accumulation accelerates. The urgency is in part driven by the emergence of systems molecular medicine that emphasizes the combination of systems analysis and molecular dissection in the future of medical practice and research. A potentially powerful approach is to build integrative pathway knowledge bases that link organ systems function with molecules.

  19. A Comparative Study of Successful Central Nervous System Drugs Using Molecular Modeling

    Science.gov (United States)

    Kim, Hyosub; Sulaimon, Segun; Menezes, Sandra; Son, Anne; Menezes, Warren J. C.

    2011-01-01

    Molecular modeling is a powerful tool used for three-dimensional visualization and for exploring electrostatic forces involved in drug transport. This tool enhances student understanding of structure-property relationships, as well as actively engaging them in class. Molecular modeling of several central nervous system (CNS) drugs is used to…

  20. Exploring coherent transport through π-stacked systems for molecular electronic devices

    DEFF Research Database (Denmark)

    Li, Qian; Solomon, Gemma

    2014-01-01

    Understanding electron transport across π-stacked systems can help to elucidate the role of intermolecular tunneling in molecular junctions and potentially with the design of high-efficiency molecular devices. Here we show how conjugation length and substituent groups influence the electron trans...

  1. The time course of repair of ultraviolet-induced DNA damage; implications for the structural organization of repair

    International Nuclear Information System (INIS)

    Collins, A.; Squires, S.

    1986-01-01

    Alternative molecular mechanisms can be envisaged for the cellular repair of UV-damaged DNA. In the 'random collision' model, DNA damage distributed throughout the genome is recognised and repaired by a process of random collision between DNA damage and repair enzymes. The other model assumes a 'processive' mechanism, whereby DNA is scanned for damage by a repair complex moving steadily along its length. Random collision should result in a declining rate of repair with time as the concentration of lesions in the DNA falls; but the processive model predicts a constant rate until scanning is complete. The authors have examined the time course of DNA repair in human fibroblasts given low doses of UV light. Using 3 distinct assays, the authors find no sign of a constant repair rate after 4 J/m 2 or less, even when the first few hours after irradiation are examined. Thus DNA repair is likely to depend on random collision. (Auth.)

  2. Molecular Dynamics Simulations of displacement cascades in metallic systems

    International Nuclear Information System (INIS)

    Doan, N.V.; Tietze, H.

    1995-01-01

    We use Molecular Dynamics Computer Simulations to investigate defect production induced by energetic displacement cascades up to 10 keV in pure metals (Cu, Ni) and in ordered intermetallic alloys NiAl, Ni 3 Al. Various model potentials were employed to describe the many-body nature of the interactions: the RGL (Rosato-Guillope-Legrand) model was used in pure Cu and Ni simulations; the modified version of the Vitek, Ackland and Cserti potentials (due to Gao, Bacon and Ackland) in Ni 3 Al and the EAM potentials of Foiles and Daw modified by Rubini and Ballone in NiAl, Ni 3 Al were used in alloy simulations. Atomic mixing and disordering were studied into details owing to imaging techniques and determined at different phases of the cascades. Some mixing mechanisms were identified. Our results were compared with existing data and those obtained by similar Molecular Dynamics Simulations available in the literature. (orig.)

  3. Molecular and supramolecular speciation of monoamide extractant systems

    International Nuclear Information System (INIS)

    Ferru, G.

    2012-01-01

    DEHiBA (N,N-di-(ethyl-2-hexyl)isobutyramide, a monoamide, was chosen as selective extractant for the recovery of uranium in the first cycle of the GANEX process, which aims to realize the grouped extraction of actinides in the second step of the process. The aim of this work is an improved description of monoamide organic solutions in alkane diluent after solutes extraction: water, nitric acid and uranyl nitrate. A parametric study was undertaken to characterize species at molecular scale (by IR spectroscopy, UV-visible spectroscopy, time-resolved laser-induced fluorescence spectroscopy, and electro-spray ionisation mass spectrometry) and at supramolecular scale (by vapor pressure osmometry and small angle X-ray scattering coupled to molecular dynamic simulations). Extraction isotherms were modelled taking into account the molecular and supramolecular speciation. These works showed that the organization of the organic solution depends on the amide concentration, the nature and the concentration of the extracted solute. Three regimes can be distinguished. 1/For extractant concentration less than 0.5 mol/L, monomers are predominate species. 2/ For extractant concentrations between 0.5 and 1 mol/L, small aggregates are formed containing 2 to 4 molecules of monoamide. 3/ For more concentrated solutions (greater than 1 mol/L), slightly larger species can be formed after water or nitric acid extraction. Concerning uranyl nitrate extraction, an important and strong organization of the organic phase is observed, which no longer allows the formation of well spherical defined aggregates. At molecular scale, complexes are not sensitive to the organization of the solution: the same species are observed, regardless of the solute and extractant concentrations in organic phase. (author) [fr

  4. The experience from operation of electronic personal dosimetry system at Dukovany, Temelin and Mochovce NPPs after repair of Siemens dosemeters eliminating false doses

    International Nuclear Information System (INIS)

    Malysak, J.; Kocvara, S.; Jurochova, B.; Zelenka, Z.; Schacherl, M.; Zrubec, M.; Kaiser, H.

    2003-01-01

    This presentation summarizes the operational experience of the Electronic Personal Dosimetry Systems installed at Dukovany, Temelin and Mochovce NPPs. The system consists of three basic parts: Electronic personal dosemeters (EPD); Physical layer (HW); Logical layer (SW). Number of false doses before and after correction is presented. This presentation has demonstrated the possibilities of SEOD system and the possibility of easy dose comparison between the individual NPPs after introducing this electronic dosimetry system. Basically, the results of film and electronic dosimetry systems are according to our findings nearly identical. Electronic dosemeter sensitivity to interfering electromagnetic fields is a problem which is easily re-movable. In addition, if we know this problem, these false doses in the SEOD system can be easily revealed (e.g. by investigation of histograms) and repaired

  5. Underwater coating repair cuts nuclear maintenance costs

    International Nuclear Information System (INIS)

    Stuart, C.O.

    1993-01-01

    This article discusses the cleaning and recoating/repair of condensate tanks or other vessels in a nuclear power plant. The topics of the article include the safety and regulatory need for this system of repair, a description of the work done on the Brown's Ferry MK-1 suppression chamber, coating failure mechanisms, qualitative inspection, quantitative inspection, quantitative inspection results, spot repairs, and economic considerations

  6. The stem cell secretome and its role in brain repair.

    Science.gov (United States)

    Drago, Denise; Cossetti, Chiara; Iraci, Nunzio; Gaude, Edoardo; Musco, Giovanna; Bachi, Angela; Pluchino, Stefano

    2013-12-01

    Compelling evidence exists that non-haematopoietic stem cells, including mesenchymal (MSCs) and neural/progenitor stem cells (NPCs), exert a substantial beneficial and therapeutic effect after transplantation in experimental central nervous system (CNS) disease models through the secretion of immune modulatory or neurotrophic paracrine factors. This paracrine hypothesis has inspired an alternative outlook on the use of stem cells in regenerative neurology. In this paradigm, significant repair of the injured brain may be achieved by injecting the biologics secreted by stem cells (secretome), rather than implanting stem cells themselves for direct cell replacement. The stem cell secretome (SCS) includes cytokines, chemokines and growth factors, and has gained increasing attention in recent years because of its multiple implications for the repair, restoration or regeneration of injured tissues. Thanks to recent improvements in SCS profiling and manipulation, investigators are now inspired to harness the SCS as a novel alternative therapeutic option that might ensure more efficient outcomes than current stem cell-based therapies for CNS repair. This review discusses the most recent identification of MSC- and NPC-secreted factors, including those that are trafficked within extracellular membrane vesicles (EVs), and reflects on their potential effects on brain repair. It also examines some of the most convincing advances in molecular profiling that have enabled mapping of the SCS. Copyright © 2013 The Authors. Published by Elsevier Masson SAS.. All rights reserved.

  7. Rapid road repair vehicle

    Science.gov (United States)

    Mara, Leo M.

    1998-01-01

    Disclosed is a rapid road repair vehicle capable of moving over a surface to be repaired at near normal posted traffic speeds to scan for and find an the high rate of speed, imperfections in the pavement surface, prepare the surface imperfection for repair by air pressure and vacuum cleaning, applying a correct amount of the correct patching material to effect the repair, smooth the resulting repaired surface, and catalog the location and quality of the repairs for maintenance records of the road surface. The rapid road repair vehicle can repair surface imperfections at lower cost, improved quality, at a higher rate of speed than was was heretofor possible, with significantly reduced exposure to safety and health hazards associated with this kind of road repair activities in the past.

  8. Molecular-beam epitaxial growth and ion-beam analysis systems for functional materials research

    International Nuclear Information System (INIS)

    Takeshita, H.; Aoki, Y.; Yamamoto, S.; Naramoto, H.

    1992-01-01

    Experimental systems for molecular beam epitaxial growth and ion beam analysis have been designed and constructed for the research of inorganic functional materials such as thin films and superlattices. (author)

  9. Materials learning from life: concepts for active, adaptive and autonomous molecular systems.

    Science.gov (United States)

    Merindol, Rémi; Walther, Andreas

    2017-09-18

    Bioinspired out-of-equilibrium systems will set the scene for the next generation of molecular materials with active, adaptive, autonomous, emergent and intelligent behavior. Indeed life provides the best demonstrations of complex and functional out-of-equilibrium systems: cells keep track of time, communicate, move, adapt, evolve and replicate continuously. Stirred by the understanding of biological principles, artificial out-of-equilibrium systems are emerging in many fields of soft matter science. Here we put in perspective the molecular mechanisms driving biological functions with the ones driving synthetic molecular systems. Focusing on principles that enable new levels of functionalities (temporal control, autonomous structures, motion and work generation, information processing) rather than on specific material classes, we outline key cross-disciplinary concepts that emerge in this challenging field. Ultimately, the goal is to inspire and support new generations of autonomous and adaptive molecular devices fueled by self-regulating chemistry.

  10. Pulse radiolysis studies of fast reactions in molecular systems. Progress report, November 1976--October 1977

    International Nuclear Information System (INIS)

    Dorfman, L.M.

    1977-01-01

    Results from research in the following two areas are given: formation, properties, and reactivity of molecular ionic species in irradiated liquid systems; and pulse radiolysis of elementary reactions in protein function

  11. Next Generation Risk Assessment: Incorporation of Recent Advances in Molecular, Computational, and Systems Biology (Final Report)

    Science.gov (United States)

    EPA announced the release of the final report, Next Generation Risk Assessment: Incorporation of Recent Advances in Molecular, Computational, and Systems Biology. This report describes new approaches that are faster, less resource intensive, and more robust that can help ...

  12. FROM ATOMISTIC TO SYSTEMATIC COARSE-GRAINED MODELS FOR MOLECULAR SYSTEMS

    KAUST Repository

    Harmandaris, Vagelis; Kalligiannaki, Evangelia; Katsoulakis, Markos; Plechac, Petr

    2017-01-01

    The development of systematic (rigorous) coarse-grained mesoscopic models for complex molecular systems is an intense research area. Here we first give an overview of methods for obtaining optimal parametrized coarse-grained models, starting from

  13. Molecular quenching and relaxation in a plasmonic tunable system

    Science.gov (United States)

    Baffou, Guillaume; Girard, Christian; Dujardin, Erik; Colas Des Francs, Gérard; Martin, Olivier J. F.

    2008-03-01

    Molecular fluorescence decay is significantly modified when the emitting molecule is located near a plasmonic structure. When the lateral sizes of such structures are reduced to nanometer-scale cross sections, they can be used to accurately control and amplify the emission rate. In this Rapid Communication, we extend Green’s dyadic method to quantitatively investigate both radiative and nonradiative decay channels experienced by a single fluorescent molecule confined in an adjustable dielectric-metal nanogap. The technique produces data in excellent agreement with current experimental work.

  14. Mixed 2D molecular systems: Mechanic, thermodynamic and dielectric properties

    Energy Technology Data Exchange (ETDEWEB)

    Beno, Juraj [Department of Physics, Faculty of Electrical Engineering and Information Technology, Slovak University of Technology, Ilkovicova 3, 812 19-SK Bratislava (Slovakia); Weis, Martin [Department of Physics, Faculty of Electrical Engineering and Information Technology, Slovak University of Technology, Ilkovicova 3, 812 19-SK Bratislava (Slovakia)], E-mail: Martin.Weis@stuba.sk; Dobrocka, Edmund [Department of Physics, Faculty of Electrical Engineering and Information Technology, Slovak University of Technology, Ilkovicova 3, 812 19-SK Bratislava (Slovakia); Institute of Electrical Engineering, Slovak Academy of Sciences, Dubravska cesta 9, 841 04-SK Bratislava (Slovakia); Hasko, Daniel [International Laser Centre, Ilkovicova 3, 812 19-SK Bratislava (Slovakia)

    2008-08-15

    Study of Langmuir monolayers consisting of stearic acid (SA) and dipalmitoylphosphatidylcholine (DPPC) molecules was done by surface pressure-area isotherms ({pi}-A), the Maxwell displacement current (MDC) measurement, X-ray reflectivity (XRR) and atomic force microscopy (AFM) to investigate the selected mechanic, thermodynamic and dielectric properties based on orientational structure of monolayers. On the base of {pi}-A isotherms analysis we explain the creation of stable structures and found optimal monolayer composition. The dielectric properties represented by MDC generated monolayers were analyzed in terms of excess dipole moment, proposing the effect of dipole-dipole interaction. XRR and AFM results illustrate deposited film structure and molecular ordering.

  15. Sustained co-delivery of BIO and IGF-1 by a novel hybrid hydrogel system to stimulate endogenous cardiac repair in myocardial infarcted rat hearts.

    Science.gov (United States)

    Fang, Rui; Qiao, Shupei; Liu, Yi; Meng, Qingyuan; Chen, Xiongbiao; Song, Bing; Hou, Xiaolu; Tian, Weiming

    2015-01-01

    Dedifferentiation and proliferation of endogenous cardiomyocytes in situ can effectively improve cardiac repair following myocardial infarction (MI). 6-Bromoindirubin-3-oxime (BIO) and insulin-like growth factor 1 (IGF-1) are two potent factors that promote cardiomyocyte survival and proliferation. However, their delivery for sustained release in MI-affected areas has proved to be challenging. In the current research, we present a study on the sustained co-delivery of BIO and IGF-1 in a hybrid hydrogel system to simulate endogenous cardiac repair in an MI rat model. Both BIO and IGF-1 were efficiently encapsulated in gelatin nanoparticles, which were later cross-linked with the oxidized alginate to form a novel hybrid hydrogel system. The in vivo results indicated that the hybrid system could enhance the proliferation of cardiomyocytes in situ and could promote revascularization around the MI sites, allowing improved cardiac function. Taken together, we concluded that the hybrid hydrogel system can co-deliver BIO and IGF-1 to areas of MI and thus improve cardiac function by promoting the proliferation of cardiomyocytes and revascularization.

  16. Sustained co-delivery of BIO and IGF-1 by a novel hybrid hydrogel system to stimulate endogenous cardiac repair in myocardial infarcted rat hearts

    Science.gov (United States)

    Fang, Rui; Qiao, Shupei; Liu, Yi; Meng, Qingyuan; Chen, Xiongbiao; Song, Bing; Hou, Xiaolu; Tian, Weiming

    2015-01-01

    Dedifferentiation and proliferation of endogenous cardiomyocytes in situ can effectively improve cardiac repair following myocardial infarction (MI). 6-Bromoindirubin-3-oxime (BIO) and insulin-like growth factor 1 (IGF-1) are two potent factors that promote cardiomyocyte survival and proliferation. However, their delivery for sustained release in MI-affected areas has proved to be challenging. In the current research, we present a study on the sustained co-delivery of BIO and IGF-1 in a hybrid hydrogel system to simulate endogenous cardiac repair in an MI rat model. Both BIO and IGF-1 were efficiently encapsulated in gelatin nanoparticles, which were later cross-linked with the oxidized alginate to form a novel hybrid hydrogel system. The in vivo results indicated that the hybrid system could enhance the proliferation of cardiomyocytes in situ and could promote revascularization around the MI sites, allowing improved cardiac function. Taken together, we concluded that the hybrid hydrogel system can co-deliver BIO and IGF-1 to areas of MI and thus improve cardiac function by promoting the proliferation of cardiomyocytes and revascularization. PMID:26251592

  17. Raman spectroscopy on simple molecular systems at very high density

    International Nuclear Information System (INIS)

    Schiferl, D.; LeSar, R.S.; Moore, D.S.

    1988-01-01

    We present an overview of how Raman spectroscopy is done on simple molecular substances at high pressures. Raman spectroscopy is one of the most powerful tools for studying these substances. It is often the quickest means to explore changes in crystal and molecular structures, changes in bond strength, and the formation of new chemical species. Raman measurements have been made at pressures up to 200 GPa (2 Mbar). Even more astonishing is the range of temperatures (4-5200/degree/K) achieved in various static and dynamic (shock-wave) pressure experiments. One point we particularly wish to emphasize is the need for a good theoretical understanding to properly interpret and use experimental results. This is particularly true at ultra-high pressures, where strong crystal field effects can be misinterpreted as incipient insulator-metal transitions. We have tried to point out apparatus, techniques, and results that we feel are particularly noteworthy. We have also included some of the /open quotes/oral tradition/close quotes/ of high pressure Raman spectroscopy -- useful little things that rarely or never appear in print. Because this field is rapidly expanding, we discuss a number of exciting new techniques that have been informally communicated to us, especially those that seem to open new possibilities. 58 refs., 18 figs

  18. 48 CFR 1371.118 - Changes-ship repair.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false Changes-ship repair. 1371.118 Section 1371.118 Federal Acquisition Regulations System DEPARTMENT OF COMMERCE DEPARTMENT SUPPLEMENTAL REGULATIONS ACQUISITIONS INVOLVING SHIP CONSTRUCTION AND SHIP REPAIR Provisions and Clauses 1371.118 Changes—ship repair. Insert clause...

  19. Nucleotide excision repair II: From yeast to mammals

    NARCIS (Netherlands)

    J.H.J. Hoeijmakers (Jan)

    1993-01-01

    textabstractAn intricate network of repair systems safeguards the integrity of genetic material, by eliminating DNA lesions induced by numerous environmental and endogenous genotoxic agents. Nucleotide excision repair (NER) is one of the most versatile DNA repair systems. Deficiencies in this

  20. Computational studies of radiation and oxidative damage to DNA and its recognition by repair enzyme

    Energy Technology Data Exchange (ETDEWEB)

    Pinak, M. [Center for Promotion of Computational Science and Engineering, Tokai Research Establishment, Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan)

    2000-03-01

    Molecular dynamics (MD) simulation is used to study the time evolution of the recognition processes and to construct a model of the specific DNA-repair enzyme' complexes. MD simulations of the following molecules were performed: DNA dodecamer with thymine dimer (TD), DNA 30-mer with thymine glycol (TG), and respective specific repair enzymes T4 Endonuclease V and Endonuclease III. Both DNA lesions are experimentally suggested to be mutagenic and carcinogenic unless properly recognized and repaired by repair enzymes. In the case of TD, there is detected a strong kink around the TD site, that is not observed in native DNA. In addition there is observed a different value of electrostatic energy at the TD site - negative '-9 kcal/mol', in contrast to the nearly neutral value of the native thymine site. These two factors - structural changes and specific electrostatic energy - seem to be important for proper recognition of a TD damaged site and for formation of DNA-enzyme complex. Formation of this complex is the onset of the repair of DNA. In the case of TG damaged DNA the structural characteristics of the TG were calculated (charges, bond lengths, bond angles, etc.). The formed TG was used to replace the native thymine and then submitted to the simulation in the system with a repair enzyme with Endonuclease III for the purpose of the study of the formation of the DNA-enzyme complex. (author)

  1. A k-out-of-n reliability system with an unreliable server and phase type repairs and services: the (N,T policy

    Directory of Open Access Journals (Sweden)

    Srinivas R. Chakravarthy

    2001-01-01

    Full Text Available In this paper we study a k-out-of-n reliability system in which a single unreliable server maintains n identical components. The reliability system is studied under the (N,T policy. An idle server takes a vacation for a random amount of time T and then attends to any failed component waiting in line upon completion of the vacation. The vacationing server is recalled instantaneously upon the failure of the Nth component. The failure times of the components are assumed to follow an exponential distribution. The server is subject to failure with failure times exponentially distributed. Repair times of the component, fixing times of the server, and vacationing times of the server are assumed to be of phase type. Using matrix-analytic methods we perform steady state analysis of this model. Time spent by a failed component in service, total time in the repair facility, vacation time of the server, non-vacation time of the server, and time until failure of the system are all shown to be of phase type. Several performance measures are evaluated. Illustrative numerical examples are presented.

  2. Optimal control of M/M/1 two-phase queueing system with state-dependent arrival rate, server breakdowns, delayed repair, and N-policy

    Science.gov (United States)

    Rao, Hanumantha; Kumar, Vasanta; Srinivasa Rao, T.; Srinivasa Kumar, B.

    2018-04-01

    In this paper, we examine a two-stage queueing system where the arrivals are Poisson with rate depends on the condition of the server to be specific: vacation, pre-service, operational or breakdown state. The service station is liable to breakdowns and deferral in repair because of non-accessibility of the repair facility. The service is in two basic stages, the first being bulk service to every one of the customers holding up on the line and the second stage is individual to each of them. The server works under N-policy. The server needs preliminary time (startup time) to begin batch service after a vacation period. Startup times, uninterrupted service times, the length of each vacation period, delay times and service times follows an exponential distribution. The closed form of expressions for the mean system size at different conditions of the server is determined. Numerical investigations are directed to concentrate the impact of the system parameters on the ideal limit N and the minimum base expected unit cost.

  3. Systems biology for molecular life sciences and its impact in biomedicine.

    Science.gov (United States)

    Medina, Miguel Ángel

    2013-03-01

    Modern systems biology is already contributing to a radical transformation of molecular life sciences and biomedicine, and it is expected to have a real impact in the clinical setting in the next years. In this review, the emergence of systems biology is contextualized with a historic overview, and its present state is depicted. The present and expected future contribution of systems biology to the development of molecular medicine is underscored. Concerning the present situation, this review includes a reflection on the "inflation" of biological data and the urgent need for tools and procedures to make hidden information emerge. Descriptions of the impact of networks and models and the available resources and tools for applying them in systems biology approaches to molecular medicine are provided as well. The actual current impact of systems biology in molecular medicine is illustrated, reviewing two cases, namely, those of systems pharmacology and cancer systems biology. Finally, some of the expected contributions of systems biology to the immediate future of molecular medicine are commented.

  4. Water activity in liquid food systems: A molecular scale interpretation.

    Science.gov (United States)

    Maneffa, Andrew J; Stenner, Richard; Matharu, Avtar S; Clark, James H; Matubayasi, Nobuyuki; Shimizu, Seishi

    2017-12-15

    Water activity has historically been and continues to be recognised as a key concept in the area of food science. Despite its ubiquitous utilisation, it still appears as though there is confusion concerning its molecular basis, even within simple, single component solutions. Here, by close examination of the well-known Norrish equation and subsequent application of a rigorous statistical theory, we are able to shed light on such an origin. Our findings highlight the importance of solute-solute interactions thus questioning traditional, empirically based "free water" and "water structure" hypotheses. Conversely, they support the theory of "solute hydration and clustering" which advocates the interplay of solute-solute and solute-water interactions but crucially, they do so in a manner which is free of any estimations and approximations. Copyright © 2017. Published by Elsevier Ltd.

  5. Online molecular image repository and analysis system: A multicenter collaborative open-source infrastructure for molecular imaging research and application.

    Science.gov (United States)

    Rahman, Mahabubur; Watabe, Hiroshi

    2018-05-01

    Molecular imaging serves as an important tool for researchers and clinicians to visualize and investigate complex biochemical phenomena using specialized instruments; these instruments are either used individually or in combination with targeted imaging agents to obtain images related to specific diseases with high sensitivity, specificity, and signal-to-noise ratios. However, molecular imaging, which is a multidisciplinary research field, faces several challenges, including the integration of imaging informatics with bioinformatics and medical informatics, requirement of reliable and robust image analysis algorithms, effective quality control of imaging facilities, and those related to individualized disease mapping, data sharing, software architecture, and knowledge management. As a cost-effective and open-source approach to address these challenges related to molecular imaging, we develop a flexible, transparent, and secure infrastructure, named MIRA, which stands for Molecular Imaging Repository and Analysis, primarily using the Python programming language, and a MySQL relational database system deployed on a Linux server. MIRA is designed with a centralized image archiving infrastructure and information database so that a multicenter collaborative informatics platform can be built. The capability of dealing with metadata, image file format normalization, and storing and viewing different types of documents and multimedia files make MIRA considerably flexible. With features like logging, auditing, commenting, sharing, and searching, MIRA is useful as an Electronic Laboratory Notebook for effective knowledge management. In addition, the centralized approach for MIRA facilitates on-the-fly access to all its features remotely through any web browser. Furthermore, the open-source approach provides the opportunity for sustainable continued development. MIRA offers an infrastructure that can be used as cross-boundary collaborative MI research platform for the rapid

  6. Repair mechanisms inducible to the DNA in I.M.M.S. biological systems; Mecanismos de reparacion inducible del ADN en sistemas biologicos I.M.M.S

    Energy Technology Data Exchange (ETDEWEB)

    Guzman, J; Arceo, C; Cortinas, C; Rosa, M.E. De la; Olvera, O; Cruces, M; Pimentel, E

    1990-03-15

    Given the characteristics of the MMS and the relative antecedents to the repair mechanisms in eucariontes are sought to determine the effect of the MMS on the genetic material and their repair in Drosophila melanogaster. (Author)

  7. Department of Molecular Biology

    International Nuclear Information System (INIS)

    Kusmierek, J.

    1998-01-01

    Full text. The majority of our studies are centered on (i) mechanisms of mutagenesis and DNA repair (including MFD) in Escherichia coli, M13, and lambda phages; (ii) inhibitory and miscoding properties of modified bases in DNA; (iii) synthesis and properties of pyrimidine nucleosides and nucleotide analogues with potential anti-tumor, anti-virus and anti-parasite activities, including their conformation and substrate/inhibitor properties in some enzyme systems of relevance to chemotherapy; (iv) molecular mechanisms of PUVA (psoralen + UVA) treatment in psoriasis photo-chemotherapy in particular its action on cell membrane; (v) specificity and methods for assays of N-alkyl-purine DNA glycosylase. The spectrum of mutagens tested includes: MMS, DMS, ultraviolet or halogen light and hydroxyl radicals. The enzymes and repair systems investigated include: DNA polymerases and the proofreading activity of DNA pol III, UvrABC-endonuclease, mismatch repair system, and methyl DNA glycosylases. Much attention is focussed on the role of UmuDC proteins in mutagenesis (dependent and independent on DNA replication) and DNA repair, and on the effect of the Tn10 transposon on the survival and mutation frequency of halogen light irradiated bacteria. A new class of nucleosides containing C(2)-hydroxymethyl-ribose (hamamelose) was synthesized, and it was found that uracil and 5-fluorouracil derivatives show a significant antitumor activity. It was found that 2CDA (2-deoxy-2-chloro-adenosine) an anti-lymphoid drug does not induce mutations, when incorporated into DNA, but significantly inhibits DNA replication. In studies with oxidized M13 DNA it was found that Fapy- (formamidopyrimidine)-residues in DNA selectively inhibits DNA synthesis, and the effect depends on the neighboring sequences and the DNA polymerase tested. Highly unstable derivatives of lecithin-psoralen adducts were characterized and their role in PUVA photochemotherapy is being studied. (author)

  8. Technology of Double Thermal Insulation for the Repair and Energy Optimization of Existing Thermal Insulation Composite Systems

    Science.gov (United States)

    Belániová, Barbora; Antošová, Naďa

    2017-06-01

    The theme of improvement thermal proprieties of external cladding according to the New EU Directive is still a hot topic, which needs to be answered necessarily till December 2020. Maintenance and repair of existing ETICS became to also an actual open theme in search solutions for existing constructions. The aim of the research in this review is to analyze influence of layers the alternative thermal materials in technology "double thermal insulation". Humidity and temperature conditions will be further examined in connection with the development and colonization of microorganisms on surface construction.

  9. Collision Repair Campaign

    Science.gov (United States)

    The Collision Repair Campaign targets meaningful risk reduction in the Collision Repair source category to reduce air toxic emissions in their communities. The Campaign also helps shops to work towards early compliance with the Auto Body Rule.

  10. Retinal detachment repair

    Science.gov (United States)

    ... medicines Problems breathing You may not recover full vision. ... detachments can be repaired. Failure to repair the retina always results in loss of vision to some degree. After surgery, the quality of ...

  11. Nuclear translocation contributes to regulation of DNA excision repair activities

    DEFF Research Database (Denmark)

    Knudsen, Nina Østergaard; Andersen, Sofie Dabros; Lützen, Anne

    2009-01-01

    for regulation of nuclear import that is necessary for proper localization of the repair proteins. This review summarizes the current knowledge on nuclear import mechanisms of DNA excision repair proteins and provides a model that categorizes the import by different mechanisms, including classical nuclear import......DNA mutations are circumvented by dedicated specialized excision repair systems, such as the base excision repair (BER), nucleotide excision repair (NER), and mismatch repair (MMR) pathways. Although the individual repair pathways have distinct roles in suppressing changes in the nuclear DNA......, it is evident that proteins from the different DNA repair pathways interact [Y. Wang, D. Cortez, P. Yazdi, N. Neff, S.J. Elledge, J. Qin, BASC, a super complex of BRCA1-associated proteins involved in the recognition and repair of aberrant DNA structures, Genes Dev. 14 (2000) 927-939; M. Christmann, M...

  12. On the optimal degree of imperfect repair

    International Nuclear Information System (INIS)

    Finkelstein, Maxim

    2015-01-01

    A simple cost-wise comparison between the minimal and perfect repair of a system is discussed first using a relevant example. The main focus of this note, however, is on imperfect (general) repair. The best repair for our system in this case is defined as the one that corresponds to the optimal level (extent) of repair actions that minimize the long-run expected cost per unit of time. This complex optimization problem is considered for a specific imperfect repair model (Kijima II), using the developed earlier asymptotic approach to the corresponding virtual age modelling. It is shown that the optimal solution exists when the failure rate of a system tends to infinity as t tends to infinity and the corresponding cost function decreases sufficiently fast. An example illustrating the optimization procedure is considered

  13. Self repairing composites for drone air vehicles

    Science.gov (United States)

    Dry, Carolyn

    2015-04-01

    The objective of this effort was to demonstrate the feasibility of impact-initiated delivery of repair chemicals through hollow fiber architectures embedded within graphite fiber reinforced polymer matrix composites, representative of advanced drone aircraft component material systems. Self-repairing structures through coupon and elements were demonstrated, and evaluated.

  14. A grass molecular identification system for forensic botany: a critical evaluation of the strengths and limitations.

    Science.gov (United States)

    Ward, Jodie; Gilmore, Simon R; Robertson, James; Peakall, Rod

    2009-11-01

    Plant material is frequently encountered in criminal investigations but often overlooked as potential evidence. We designed a DNA-based molecular identification system for 100 Australian grasses that consisted of a series of polymerase chain reaction assays that enabled the progressive identification of grasses to different taxonomic levels. The identification system was based on DNA sequence variation at four chloroplast and two mitochondrial loci. Seventeen informative indels and 68 single-nucleotide polymorphisms were utilized as molecular markers for subfamily to species-level identification. To identify an unknown sample to subfamily level required a minimum of four markers or nine markers for species identification. The accuracy of the system was confirmed by blind tests. We have demonstrated "proof of concept" of a molecular identification system for trace botanical samples. Our evaluation suggests that the adoption of a system that combines this approach with DNA sequencing could assist the morphological identification of grasses found as forensic evidence.

  15. Influence of percutaneous mitral valve repair using the MitraClip® system on renal function in patients with severe mitral regurgitation.

    Science.gov (United States)

    Rassaf, Tienush; Balzer, Jan; Rammos, Christos; Zeus, Tobias; Hellhammer, Katharina; v Hall, Silke; Wagstaff, Rabea; Kelm, Malte

    2015-04-01

    In patients with mitral regurgitation (MR), changes in cardiac stroke volume, and thus renal preload and afterload may affect kidney function. Percutaneous mitral valve repair (PMVR) with the MitraClip® system can be a therapeutic alternative to surgical valve repair. The influence of MitraClip® therapy on renal function and clinical outcome parameters is unknown. Sixty patients with severe MR underwent PMVR using the MitraClip® system in an open-label observational study. Patients were stratified according to their renal function. All clips have been implanted successfully. Effective reduction of MR by 2-3 grades acutely improved KDOQI class. Lesser MR reduction (MR reduction of 0-1 grades) led to worsening of renal function in patients with pre-existing normal or mild (KDOQI 1-2) compared to severe (KDOQI 3-4) renal dysfunction. Reduction of MR was associated with improvement in Minnesota Living with Heart Failure Questionnaire (MLHFQ), NYHA-stadium, and 6-minute walk test. Successful PMVR was associated with an improvement in renal function. The improvement in renal function was associated with the extent of MR reduction and pre-existing kidney dysfunction. Our data emphasize the relevance of PVMR to stabilize the cardiorenal axis in patients with severe MR. © 2014 Wiley Periodicals, Inc.

  16. The rise of a novel classification system for endometrial carcinoma; integration of molecular subclasses.

    Science.gov (United States)

    McAlpine, Jessica; Leon-Castillo, Alicia; Bosse, Tjalling

    2018-04-01

    Endometrial cancer is a clinically heterogeneous disease and it is becoming increasingly clear that this heterogeneity may be a function of the diversity of the underlying molecular alterations. Recent large-scale genomic studies have revealed that endometrial cancer can be divided into at least four distinct molecular subtypes, with well-described underlying genomic aberrations. These subtypes can be reliably delineated and carry significant prognostic as well as predictive information; embracing and incorporating them into clinical practice is thus attractive. The road towards the integration of molecular features into current classification systems is not without obstacles. Collaborative studies engaging research teams from across the world are working to define pragmatic assays, improve risk stratification systems by combining molecular features and traditional clinicopathological parameters, and determine how molecular classification can be optimally utilized to direct patient care. Pathologists and clinicians caring for women with endometrial cancer need to engage with and understand the possibilities and limitations of this new approach, because integration of molecular classification of endometrial cancers is anticipated to become an essential part of gynaecological pathology practice. This review will describe the challenges in current systems of endometrial carcinoma classification, the evolution of new molecular technologies that define prognostically distinct molecular subtypes, and potential applications of molecular classification as a step towards precision medicine and refining care for individuals with the most common gynaecological cancer in the developed world. Copyright © 2018 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd. Copyright © 2018 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

  17. Calculation on uranium carbon oxygen system molecular structure by DFT

    International Nuclear Information System (INIS)

    Zhang Guangfeng; Wang Xiaolin; Zou Lexi; Sun Ying; Xue Weidong; Zhu Zhenghe; Wang Hongyan

    2001-01-01

    The authors study on the possible molecular structures U-C-O, U-O-C, C-U-O (angular structure C a nd linear structure C ∞υ ) of carbon monoxide interacting on uranium metal surface by Density functional theory (DFT). The uranium atom is used RECP (Relativistic Effective Core Potential) and contracted valence basis sets (6s5p2d4f)/[3s3p2d2f], and for carbon and oxygen atoms all are 6-311G basis sets. The author presents the results of energy optimum which shows that triple and quintuple state are more stable. The authors get the electronic state, geometry structure, energy, harmonic frequency, mechanical property, etc. of these twelve triple and quintuple state relative stable structures. The normal vibrational analytical figure of angular structure (C s ) and linear structure (C ∞υ ) is given at the same time. It is indicated that angular structure has lower energy than linear structure, moreover the angular structure of U-C-O( 3 A ) has the lowest energy. The bond strength between uranium atom and carbon monoxide is weak and between uranium atom and oxygen atom is slightly stronger than between uranium atom and carbon atom which the authors can know by superposition population and bond energy analysis among atoms

  18. Promoting peripheral myelin repair.

    Science.gov (United States)

    Zhou, Ye; Notterpek, Lucia

    2016-09-01

    Compared to the central nervous system (CNS), peripheral nerves have a remarkable ability to regenerate and remyelinate. This regenerative capacity to a large extent is dependent on and supported by Schwann cells, the myelin-forming glial cells of the peripheral nervous system (PNS). In a variety of paradigms, Schwann cells are critical in the removal of the degenerated tissue, which is followed by remyelination of newly-regenerated axons. This unique plasticity of Schwann cells has been the target of myelin repair strategies in acute injuries and chronic diseases, such as hereditary demyelinating neuropathies. In one approach, the endogenous regenerative capacity of Schwann cells is enhanced through interventions such as exercise, electrical stimulation or pharmacological means. Alternatively, Schwann cells derived from healthy nerves, or engineered from different tissue sources have been transplanted into the PNS to support remyelination. These transplant approaches can then be further enhanced by exercise and/or electrical stimulation, as well as by the inclusion of biomaterial engineered to support glial cell viability and neurite extension. Advances in our basic understanding of peripheral nerve biology, as well as biomaterial engineering, will further improve the functional repair of myelinated peripheral nerves. Copyright © 2016 Elsevier Inc. All rights reserved.

  19. Molecular characterization of the thioredoxin system from Methanosarcina acetivorans

    OpenAIRE

    McCarver, Addison C.; Lessner, Daniel J.

    2014-01-01

    The thioredoxin system, composed of thioredoxin reductase (TrxR) and thioredoxin (Trx), is widely distributed in nature, where it serves key roles in electron transfer and in defense against oxidative stress. Although recent evidence reveals Trx homologues are almost universally present among the methane-producing archaea (methanogens), a complete thioredoxin system has not been characterized from any methanogen. We examined the phylogeny of Trx homologues among methanogens and characterized ...

  20. Molecular spectral imaging system for quantitative immunohistochemical analysis of early diabetic retinopathy.

    Science.gov (United States)

    Li, Qingli; Zhang, Jingfa; Wang, Yiting; Xu, Guoteng

    2009-12-01

    A molecular spectral imaging system has been developed based on microscopy and spectral imaging technology. The system is capable of acquiring molecular spectral images from 400 nm to 800 nm with 2 nm wavelength increments. The basic principles, instrumental systems, and system calibration method as well as its applications for the calculation of the stain-uptake by tissues are introduced. As a case study, the system is used for determining the pathogenesis of diabetic retinopathy and evaluating the therapeutic effects of erythropoietin. Some molecular spectral images of retinal sections of normal, diabetic, and treated rats were collected and analyzed. The typical transmittance curves of positive spots stained for albumin and advanced glycation end products are retrieved from molecular spectral data with the spectral response calibration algorithm. To explore and evaluate the protective effect of erythropoietin (EPO) on retinal albumin leakage of streptozotocin-induced diabetic rats, an algorithm based on Beer-Lambert's law is presented. The algorithm can assess the uptake by histologic retinal sections of stains used in quantitative pathology to label albumin leakage and advanced glycation end products formation. Experimental results show that the system is helpful for the ophthalmologist to reveal the pathogenesis of diabetic retinopathy and explore the protective effect of erythropoietin on retinal cells of diabetic rats. It also highlights the potential of molecular spectral imaging technology to provide more effective and reliable diagnostic criteria in pathology.