Screen for mitochondrial DNA copy number maintenance genes reveals essential role for ATP synthase

PubMed Central

Fukuoh, Atsushi; Cannino, Giuseppe; Gerards, Mike; Buckley, Suzanne; Kazancioglu, Selena; Scialo, Filippo; Lihavainen, Eero; Ribeiro, Andre; Dufour, Eric; Jacobs, Howard T

2014-01-01

The machinery of mitochondrial DNA (mtDNA) maintenance is only partially characterized and is of wide interest due to its involvement in disease. To identify novel components of this machinery, plus other cellular pathways required for mtDNA viability, we implemented a genome-wide RNAi screen in Drosophila S2 cells, assaying for loss of fluorescence of mtDNA nucleoids stained with the DNA-intercalating agent PicoGreen. In addition to previously characterized components of the mtDNA replication and transcription machineries, positives included many proteins of the cytosolic proteasome and ribosome (but not the mitoribosome), three proteins involved in vesicle transport, some other factors involved in mitochondrial biogenesis or nuclear gene expression, > 30 mainly uncharacterized proteins and most subunits of ATP synthase (but no other OXPHOS complex). ATP synthase knockdown precipitated a burst of mitochondrial ROS production, followed by copy number depletion involving increased mitochondrial turnover, not dependent on the canonical autophagy machinery. Our findings will inform future studies of the apparatus and regulation of mtDNA maintenance, and the role of mitochondrial bioenergetics and signaling in modulating mtDNA copy number. PMID:24952591

30 CFR 75.1508 - Training and records for examination, maintenance and repair of refuge alternatives and components.

Code of Federal Regulations, 2010 CFR

2010-07-01

... repair, the person conducting the maintenance or repair shall make a record of all corrective action..., maintenance and repair of refuge alternatives and components. 75.1508 Section 75.1508 Mineral Resources MINE..., maintenance and repair of refuge alternatives and components. (a) Persons examining, maintaining, or repairing...

Machine Maintenance Scheduling with Reliability Engineering Method and Maintenance Value Stream Mapping

NASA Astrophysics Data System (ADS)

Sembiring, N.; Nasution, A. H.

2018-02-01

Corrective maintenance i.e replacing or repairing the machine component after machine break down always done in a manufacturing company. It causes the production process must be stopped. Production time will decrease due to the maintenance team must replace or repair the damage machine component. This paper proposes a preventive maintenance’s schedule for a critical component of a critical machine of an crude palm oil and kernel company due to increase maintenance efficiency. The Reliability Engineering & Maintenance Value Stream Mapping is used as a method and a tool to analize the reliability of the component and reduce the wastage in any process by segregating value added and non value added activities.

Dynamical signatures of isometric force control as a function of age, expertise, and task constraints.

PubMed

Vieluf, Solveig; Sleimen-Malkoun, Rita; Voelcker-Rehage, Claudia; Jirsa, Viktor; Reuter, Eva-Maria; Godde, Ben; Temprado, Jean-Jacques; Huys, Raoul

2017-07-01

From the conceptual and methodological framework of the dynamical systems approach, force control results from complex interactions of various subsystems yielding observable behavioral fluctuations, which comprise both deterministic (predictable) and stochastic (noise-like) dynamical components. Here, we investigated these components contributing to the observed variability in force control in groups of participants differing in age and expertise level. To this aim, young (18-25 yr) as well as late middle-aged (55-65 yr) novices and experts (precision mechanics) performed a force maintenance and a force modulation task. Results showed that whereas the amplitude of force variability did not differ across groups in the maintenance tasks, in the modulation task it was higher for late middle-aged novices than for experts and higher for both these groups than for young participants. Within both tasks and for all groups, stochastic fluctuations were lowest where the deterministic influence was smallest. However, although all groups showed similar dynamics underlying force control in the maintenance task, a group effect was found for deterministic and stochastic fluctuations in the modulation task. The latter findings imply that both components were involved in the observed group differences in the variability of force fluctuations in the modulation task. These findings suggest that between groups the general characteristics of the dynamics do not differ in either task and that force control is more affected by age than by expertise. However, expertise seems to counteract some of the age effects. NEW & NOTEWORTHY Stochastic and deterministic dynamical components contribute to force production. Dynamical signatures differ between force maintenance and cyclic force modulation tasks but hardly between age and expertise groups. Differences in both stochastic and deterministic components are associated with group differences in behavioral variability, and observed behavioral variability is more strongly task dependent than person dependent. Copyright © 2017 the American Physiological Society.

Break-induced telomere synthesis underlies alternative telomere maintenance

PubMed Central

Dilley, Robert L.; Verma, Priyanka; Cho, Nam Woo; Winters, Harrison D.; Wondisford, Anne R.; Greenberg, Roger A.

2017-01-01

Homology-directed DNA repair is essential for genome maintenance through templated DNA synthesis. Alternative lengthening of telomeres (ALT) necessitates homology-directed DNA repair to maintain telomeres in about 10–15% of human cancers. How DNA damage induces assembly and execution of a DNA replication complex (break-induced replisome) at telomeres or elsewhere in the mammalian genome is poorly understood. Here we define break-induced telomere synthesis and demonstrate that it utilizes a specialized replisome, which underlies ALT telomere maintenance. DNA double-strand breaks enact nascent telomere synthesis by long-tract unidirectional replication. Proliferating cell nuclear antigen (PCNA) loading by replication factor C (RFC) acts as the initial sensor of telomere damage to establish predominance of DNA polymerase δ (Pol δ) through its POLD3 subunit. Break-induced telomere synthesis requires the RFC–PCNA–Pol δ axis, but is independent of other canonical replisome components, ATM and ATR, or the homologous recombination protein Rad51. Thus, the inception of telomere damage recognition by the break-induced replisome orchestrates homology-directed telomere maintenance. PMID:27760120

Identification of key transcription factors in caerulein-induced pancreatitis through expression profiling data

PubMed Central

QI, DACHUAN; WU, BO; TONG, DANIAN; PAN, YE; CHEN, WEI

2015-01-01

The current study aimed to isolate key transcription factors (TFs) in caerulein-induced pancreatitis, and to identify the difference between wild type and Mist1 knockout (KO) mice, in order to elucidate the contribution of Mist1 to pancreatitis. The gene profile of GSE3644 was downloaded from the Gene Expression Omnibus database then analyzed using the t-test. The isolated differentially expressed genes (DEGs) were mapped into a transcriptional regulatory network derived from the Integrated Transcription Factor Platform database and in the network, the interaction pairs involving at least one DEG were screened. Fisher’s exact test was used to analyze the functional enrichment of the target genes. A total of 1,555 and 3,057 DEGs were identified in the wild type and Mist1KO mice treated with caerulein, respectively. DEGs screened in Mist1KO mice were predominantly enriched in apoptosis, mitogen-activated protein kinase signaling and other cancer-associated pathways. A total of 188 and 51 TFs associated with pathopoiesis were isolated in Mist1KO and wild type mice, respectively. Out of the top 10 TFs (ranked by P-value), 7 TFs, including S-phase kinase-associated protein 2 (Skp2); minichromosome maintenance complex component 3 (Mcm3); cell division cycle 6 (Cdc6); cyclin B1 (Ccnb1); mutS homolog 6 (Msh6); cyclin A2 (Ccna2); and cyclin B2 (Ccnb2), were expressed in the two types of mouse. These TFs were predominantly involved in phosphorylation, DNA replication, cell division and DNA mismatch repair. In addition, specific TFs, including minichromosome maintenance complex component 7 (Mcm7); lymphoid-specific helicase (Hells); and minichromosome maintenance complex component 6 (Mcm6), that function in the unwinding of DNA were identified to participate in Mist1KO pancreatitis. The DEGs, including Cdc6, Mcm6, Msh6 and Wdr1 are closely associated with the regulation of caerulein-induced pancreatitis. Furthermore, other identified TFs were also involved in this type of regulation. PMID:25975747

A particle swarm model for estimating reliability and scheduling system maintenance

NASA Astrophysics Data System (ADS)

Puzis, Rami; Shirtz, Dov; Elovici, Yuval

2016-05-01

Modifying data and information system components may introduce new errors and deteriorate the reliability of the system. Reliability can be efficiently regained with reliability centred maintenance, which requires reliability estimation for maintenance scheduling. A variant of the particle swarm model is used to estimate reliability of systems implemented according to the model view controller paradigm. Simulations based on data collected from an online system of a large financial institute are used to compare three component-level maintenance policies. Results show that appropriately scheduled component-level maintenance greatly reduces the cost of upholding an acceptable level of reliability by reducing the need in system-wide maintenance.

Overall Architecture of the Intraflagellar Transport (IFT)-B Complex Containing Cluap1/IFT38 as an Essential Component of the IFT-B Peripheral Subcomplex.

PubMed

Katoh, Yohei; Terada, Masaya; Nishijima, Yuya; Takei, Ryota; Nozaki, Shohei; Hamada, Hiroshi; Nakayama, Kazuhisa

2016-05-20

Intraflagellar transport (IFT) is essential for assembly and maintenance of cilia and flagella as well as ciliary motility and signaling. IFT is mediated by multisubunit complexes, including IFT-A, IFT-B, and the BBSome, in concert with kinesin and dynein motors. Under high salt conditions, purified IFT-B complex dissociates into a core subcomplex composed of at least nine subunits and at least five peripherally associated proteins. Using the visible immunoprecipitation assay, which we recently developed as a convenient protein-protein interaction assay, we determined the overall architecture of the IFT-B complex, which can be divided into core and peripheral subcomplexes composed of 10 and 6 subunits, respectively. In particular, we identified TTC26/IFT56 and Cluap1/IFT38, neither of which was included with certainty in previous models of the IFT-B complex, as integral components of the core and peripheral subcomplexes, respectively. Consistent with this, a ciliogenesis defect of Cluap1-deficient mouse embryonic fibroblasts was rescued by exogenous expression of wild-type Cluap1 but not by mutant Cluap1 lacking the binding ability to other IFT-B components. The detailed interaction map as well as comparison of subcellular localization of IFT-B components between wild-type and Cluap1-deficient cells provides insights into the functional relevance of the architecture of the IFT-B complex. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

Overall Architecture of the Intraflagellar Transport (IFT)-B Complex Containing Cluap1/IFT38 as an Essential Component of the IFT-B Peripheral Subcomplex*

PubMed Central

Katoh, Yohei; Terada, Masaya; Nishijima, Yuya; Takei, Ryota; Nozaki, Shohei; Hamada, Hiroshi; Nakayama, Kazuhisa

2016-01-01

Intraflagellar transport (IFT) is essential for assembly and maintenance of cilia and flagella as well as ciliary motility and signaling. IFT is mediated by multisubunit complexes, including IFT-A, IFT-B, and the BBSome, in concert with kinesin and dynein motors. Under high salt conditions, purified IFT-B complex dissociates into a core subcomplex composed of at least nine subunits and at least five peripherally associated proteins. Using the visible immunoprecipitation assay, which we recently developed as a convenient protein-protein interaction assay, we determined the overall architecture of the IFT-B complex, which can be divided into core and peripheral subcomplexes composed of 10 and 6 subunits, respectively. In particular, we identified TTC26/IFT56 and Cluap1/IFT38, neither of which was included with certainty in previous models of the IFT-B complex, as integral components of the core and peripheral subcomplexes, respectively. Consistent with this, a ciliogenesis defect of Cluap1-deficient mouse embryonic fibroblasts was rescued by exogenous expression of wild-type Cluap1 but not by mutant Cluap1 lacking the binding ability to other IFT-B components. The detailed interaction map as well as comparison of subcellular localization of IFT-B components between wild-type and Cluap1-deficient cells provides insights into the functional relevance of the architecture of the IFT-B complex. PMID:26980730

Niche Extracellular Matrix Components and Their Influence on HSC.

PubMed

Domingues, Mélanie J; Cao, Huimin; Heazlewood, Shen Y; Cao, Benjamin; Nilsson, Susan K

2017-08-01

Maintenance of hematopoietic stem cells (HSC) takes place in a highly specialized microenvironment within the bone marrow. Technological improvements, especially in the field of in vivo imaging, have helped unravel the complexity of the niche microenvironment and have completely changed the classical concept from what was previously believed to be a static supportive platform, to a dynamic microenvironment tightly regulating HSC homeostasis through the complex interplay between diverse cell types, secreted factors, extracellular matrix molecules, and the expression of different transmembrane receptors. To add to the complexity, non-protein based metabolites have also been recognized as a component of the bone marrow niche. The objective of this review is to discuss the current understanding on how the different extracellular matrix components of the niche regulate HSC fate, both during embryonic development and in adulthood. Special attention will be provided to the description of non-protein metabolites, such as lipids and metal ions, which contribute to the regulation of HSC behavior. J. Cell. Biochem. 118: 1984-1993, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Male reproductive strategy and decreased longevity.

PubMed

Vinogradov, A E

1998-06-01

An explanation of the inter-gender difference in longevity consistent with the 'disposable soma' theory of ageing is proposed. It is based on the concept of r-K selection as applied to the inter-gender situation. The concept predicts that the gender with a higher potential reproductive rate (males) should invest relatively less in somatic maintenance, which in its turn should result in a lower longevity according to the 'disposable soma' theory of ageing. In females, which are interpreted as K-selected organisms, the reproductive strategy strongly depends on steady, secure constitution designed for oocyte/embryo bearing and is therefore closely related to somatic maintenance, whereas in (r-selected) males it has a greater behavioural component--risky, variable, with a greater potential productive success at the expense of somatic maintenance. The higher metabolic and growth rates, a higher premature mortality and a longer period of sexual competence of males also find explanation as a complex of r-selected traits.

Future-oriented maintenance strategy based on automated processes is finding its way into large astronomical facilities at remote observing sites

NASA Astrophysics Data System (ADS)

Silber, Armin; Gonzalez, Christian; Pino, Francisco; Escarate, Patricio; Gairing, Stefan

2014-08-01

With expanding sizes and increasing complexity of large astronomical observatories on remote observing sites, the call for an efficient and recourses saving maintenance concept becomes louder. The increasing number of subsystems on telescopes and instruments forces large observatories, like in industries, to rethink conventional maintenance strategies for reaching this demanding goal. The implementation of full-, or semi-automatic processes for standard service activities can help to keep the number of operating staff on an efficient level and to reduce significantly the consumption of valuable consumables or equipment. In this contribution we will demonstrate on the example of the 80 Cryogenic subsystems of the ALMA Front End instrument, how an implemented automatic service process increases the availability of spare parts and Line Replaceable Units. Furthermore how valuable staff recourses can be freed from continuous repetitive maintenance activities, to allow focusing more on system diagnostic tasks, troubleshooting and the interchanging of line replaceable units. The required service activities are decoupled from the day-to-day work, eliminating dependencies on workload peaks or logistic constrains. The automatic refurbishing processes running in parallel to the operational tasks with constant quality and without compromising the performance of the serviced system components. Consequentially that results in an efficiency increase, less down time and keeps the observing schedule on track. Automatic service processes in combination with proactive maintenance concepts are providing the necessary flexibility for the complex operational work structures of large observatories. The gained planning flexibility is allowing an optimization of operational procedures and sequences by considering the required cost efficiency.

Effects of load and maintenance duration on the time course of information encoding and retrieval in working memory: from perceptual analysis to post-categorization processes.

PubMed

Pinal, Diego; Zurrón, Montserrat; Díaz, Fernando

2014-01-01

information encoding, maintenance, and retrieval; these are supported by brain activity in a network of frontal, parietal and temporal regions. Manipulation of WM load and duration of the maintenance period can modulate this activity. Although such modulations have been widely studied using the event-related potentials (ERP) technique, a precise description of the time course of brain activity during encoding and retrieval is still required. Here, we used this technique and principal component analysis to assess the time course of brain activity during encoding and retrieval in a delayed match to sample task. We also investigated the effects of memory load and duration of the maintenance period on ERP activity. Brain activity was similar during information encoding and retrieval and comprised six temporal factors, which closely matched the latency and scalp distribution of some ERP components: P1, N1, P2, N2, P300, and a slow wave. Changes in memory load modulated task performance and yielded variations in frontal lobe activation. Moreover, the P300 amplitude was smaller in the high than in the low load condition during encoding and retrieval. Conversely, the slow wave amplitude was higher in the high than in the low load condition during encoding, and the same was true for the N2 amplitude during retrieval. Thus, during encoding, memory load appears to modulate the processing resources for context updating and post-categorization processes, and during retrieval it modulates resources for stimulus classification and context updating. Besides, despite the lack of differences in task performance related to duration of the maintenance period, larger N2 amplitude and stronger activation of the left temporal lobe after long than after short maintenance periods were found during information retrieval. Thus, results regarding the duration of maintenance period were complex, and future work is required to test the time-based decay theory predictions.

40 CFR 35.2206 - Operation and maintenance.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Section 35.2206 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY GRANTS AND OTHER FEDERAL... operation and maintenance manual. (2) In projects where a component is placed in operation before completion... project until a final operation and maintenance manual for the operating component is furnished and...

An in vivo requirement for the mediator subunit med14 in the maintenance of stem cell populations.

PubMed

Burrows, Jeffrey T A; Pearson, Bret J; Scott, Ian C

2015-04-14

The Mediator complex has recently been shown to be a key player in the maintenance of embryonic and induced pluripotent stem cells. However, the in vivo consequences of loss of many Mediator subunits are unknown. We identified med14 as the gene affected in the zebrafish logelei (log) mutant, which displayed a morphological arrest by 2 days of development. Surprisingly, microarray analysis showed that transcription was not broadly affected in log mutants. Indeed, log cells transplanted into a wild-type environment were able to survive into adulthood. In planarians, RNAi knockdown demonstrated a requirement for med14 and many other Mediator components in adult stem cell maintenance and regeneration. Multiple stem/progenitor cell populations were observed to be reduced or absent in zebrafish med14 mutant embryos. Taken together, our results show a critical, evolutionarily conserved, in vivo function for Med14 (and Mediator) in stem cell maintenance, distinct from a general role in transcription. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

Essential Oils Loaded in Nanosystems: A Developing Strategy for a Successful Therapeutic Approach

PubMed Central

Bilia, Anna Rita; Guccione, Clizia; Isacchi, Benedetta; Righeschi, Chiara; Firenzuoli, Fabio; Bergonzi, Maria Camilla

2014-01-01

Essential oils are complex blends of a variety of volatile molecules such as terpenoids, phenol-derived aromatic components, and aliphatic components having a strong interest in pharmaceutical, sanitary, cosmetic, agricultural, and food industries. Since the middle ages, essential oils have been widely used for bactericidal, virucidal, fungicidal, antiparasitical, insecticidal, and other medicinal properties such as analgesic, sedative, anti-inflammatory, spasmolytic, and locally anaesthetic remedies. In this review their nanoencapsulation in drug delivery systems has been proposed for their capability of decreasing volatility, improving the stability, water solubility, and efficacy of essential oil-based formulations, by maintenance of therapeutic efficacy. Two categories of nanocarriers can be proposed: polymeric nanoparticulate formulations, extensively studied with significant improvement of the essential oil antimicrobial activity, and lipid carriers, including liposomes, solid lipid nanoparticles, nanostructured lipid particles, and nano- and microemulsions. Furthermore, molecular complexes such as cyclodextrin inclusion complexes also represent a valid strategy to increase water solubility and stability and bioavailability and decrease volatility of essential oils. PMID:24971152

Ultra-Low Power Optical Sensor for Xylophagous Insect Detection in Wood.

PubMed

Perles, Angel; Mercado, Ricardo; Capella, Juan V; Serrano, Juan José

2016-11-23

The early detection of pests is key for the maintenance of high-value masterpieces and historical buildings made of wood. In this work, we the present detailed design of an ultra-low power sensor device that permits the continuous monitoring of the presence of termites and other xylophagous insects. The operating principle of the sensor is based on the variations of reflected light induced by the presence of termites, and specific processing algorithms that deal with the behavior of the electronics and the natural ageing of components. With a typical CR2032 lithium battery, the device lasts more than nine years, and is ideal for incorporation in more complex monitoring systems where maintenance tasks should be minimized.

Ultra-Low Power Optical Sensor for Xylophagous Insect Detection in Wood

PubMed Central

Perles, Angel; Mercado, Ricardo; Capella, Juan V.; Serrano, Juan José

2016-01-01

The early detection of pests is key for the maintenance of high-value masterpieces and historical buildings made of wood. In this work, we the present detailed design of an ultra-low power sensor device that permits the continuous monitoring of the presence of termites and other xylophagous insects. The operating principle of the sensor is based on the variations of reflected light induced by the presence of termites, and specific processing algorithms that deal with the behavior of the electronics and the natural ageing of components. With a typical CR2032 lithium battery, the device lasts more than nine years, and is ideal for incorporation in more complex monitoring systems where maintenance tasks should be minimized. PMID:27886082

Drosophila RISC component VIG and its homolog Vig2 impact heterochromatin formation.

PubMed

Gracheva, Elena; Dus, Monica; Elgin, Sarah C R

2009-07-08

Heterochromatin formation plays an important role in gene regulation and the maintenance of genome integrity. Here we present results from a study of the D. melanogaster gene vig, encoding an RNAi complex component and its homolog vig2 (CG11844) that support their involvement in heterochromatin formation and/or maintenance. Protein null mutations vig(EP812) and vig2(PL470) act as modifiers of Position Effect Variegation (PEV). VIG and Vig2 are present in polytene chromosomes and partially overlap with HP1. Quantitative immunoblots show depletion of HP1 and HP2 (large isoform) in isolated nuclei from the vig(EP812) mutant. The vig2(PL470) mutant strain demonstrates a decreased level of H3K9me2. Pull-down experiments using antibodies specific to HP1 recovered both VIG and Vig2. The association between HP1 and both VIG and Vig2 proteins depends on an RNA component. The above data and the developmental profiles of the two genes suggest that Vig2 may be involved in heterochromatin targeting and establishment early in development, while VIG may have a role in stabilizing HP1/HP2 chromatin binding during later stages.

Software For Graphical Representation Of A Network

NASA Technical Reports Server (NTRS)

Mcallister, R. William; Mclellan, James P.

1993-01-01

System Visualization Tool (SVT) computer program developed to provide systems engineers with means of graphically representing networks. Generates diagrams illustrating structures and states of networks defined by users. Provides systems engineers powerful tool simplifing analysis of requirements and testing and maintenance of complex software-controlled systems. Employs visual models supporting analysis of chronological sequences of requirements, simulation data, and related software functions. Applied to pneumatic, hydraulic, and propellant-distribution networks. Used to define and view arbitrary configurations of such major hardware components of system as propellant tanks, valves, propellant lines, and engines. Also graphically displays status of each component. Advantage of SVT: utilizes visual cues to represent configuration of each component within network. Written in Turbo Pascal(R), version 5.0.

Assessing inspection sensitivity as it relates to damage tolerance in composite rotor hubs

NASA Astrophysics Data System (ADS)

Roach, Dennis P.; Rackow, Kirk

2001-08-01

Increasing niche applications, growing international markets, and the emergence of advanced rotorcraft technology are expected to greatly increase the population of helicopters over the next decade. In terms of fuselage fatigue, helicopters show similar trends as fixed-wing aircraft. The highly unsteady loads experienced by rotating wings not only directly affect components in the dynamic systems but are also transferred to the fixed airframe structure. Expanded use of rotorcraft has focused attention on the use of new materials and the optimization of maintenance practices. The FAA's Airworthiness Assurance Center (AANC) at Sandia National Labs has joined with Bell Helicopter andother agencies in the rotorcraft industry to evaluate nondestructive inspection (NDI) capabilities in light of the damage tolerance of assorted rotorcraft structure components. Currently, the program's emphasis is on composite rotor hubs. The rotorcraft industry is constantly evaluating new types of lightweight composite materials that not only enhance the safety and reliability of rotor components but also improve performance and extended operating life as well. Composite rotor hubs have led to the use of bearingless rotor systems that are less complex and require less maintenance than their predecessors. The test facility described in this paper allows the structural stability and damage tolerance of composite hubs to be evaluated using realistic flight load spectrums of centrifugal force and bending loads. NDI was integrated into the life-cycle fatigue tests in order to evaluate flaw detection sensitivity simultaneously wiht residual strength and general rotor hub peformance. This paper will describe the evolving use of damage tolerance analysis (DTA) to direct and improve rotorcraft maintenance along with the related use of nondestructive inspections to manage helicopter safety. OVeralll, the data from this project will provide information to improve the producibility, inspectability, serviceability, and cost effectively of rotorcraft components.

Carotenoids, versatile components of oxygenic photosynthesis.

PubMed

Domonkos, Ildikó; Kis, Mihály; Gombos, Zoltán; Ughy, Bettina

2013-10-01

Carotenoids (CARs) are a group of pigments that perform several important physiological functions in all kingdoms of living organisms. CARs serve as protective agents, which are essential structural components of photosynthetic complexes and membranes, and they play an important role in the light harvesting mechanism of photosynthesizing plants and cyanobacteria. The protection against reactive oxygen species, realized by quenching of singlet oxygen and the excited states of photosensitizing molecules, as well as by the scavenging of free radicals, is one of the main biological functions of CARs. X-ray crystallographic localization of CARs revealed that they are present at functionally and structurally important sites of both the PSI and PSII reaction centers. Characterization of a CAR-less cyanobacterial mutant revealed that while the absence of CARs prevents the formation of PSII complexes, it does not abolish the assembly and function of PSI. CAR molecules assist in the formation of protein subunits of the photosynthetic complexes by gluing together their protein components. In addition to their aforementioned indispensable functions, CARs have a substantial role in the formation and maintenance of proper cellular architecture, and potentially also in the protection of the translational machinery under stress conditions. Copyright © 2013 Elsevier Ltd. All rights reserved.

Phosphorylation of Minichromosome Maintenance 3 (MCM3) by Checkpoint Kinase 1 (Chk1) Negatively Regulates DNA Replication and Checkpoint Activation.

PubMed

Han, Xiangzi; Mayca Pozo, Franklin; Wisotsky, Jacob N; Wang, Benlian; Jacobberger, James W; Zhang, Youwei

2015-05-08

Mechanisms controlling DNA replication and replication checkpoint are critical for the maintenance of genome stability and the prevention or treatment of human cancers. Checkpoint kinase 1 (Chk1) is a key effector protein kinase that regulates the DNA damage response and replication checkpoint. The heterohexameric minichromosome maintenance (MCM) complex is the core component of mammalian DNA helicase and has been implicated in replication checkpoint activation. Here we report that Chk1 phosphorylates the MCM3 subunit of the MCM complex at Ser-205 under normal growth conditions. Mutating the Ser-205 of MCM3 to Ala increased the length of DNA replication track and shortened the S phase duration, indicating that Ser-205 phosphorylation negatively controls normal DNA replication. Upon replicative stress treatment, the inhibitory phosphorylation of MCM3 at Ser-205 was reduced, and this reduction was accompanied with the generation of single strand DNA, the key platform for ataxia telangiectasia mutated and Rad3-related (ATR) activation. As a result, the replication checkpoint is activated. Together, these data provide significant insights into the regulation of both normal DNA replication and replication checkpoint activation through the novel phosphorylation of MCM3 by Chk1. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

Management Aspects of Software Maintenance.

DTIC Science & Technology

1984-09-01

educated in * the complex nature of software maintenance to be able to properly evaluate and manage the software maintenance effort. In this...maintenance and improvement may be called "software evolution". The soft- ware manager must be Educated in the complex nature cf soft- Iware maintenance to be...complaint of error or request for modification is also studied in order to determine what action needs tc be taken. 2. Define Objective and Approach :

Drosophila as a model system to study autophagy.

PubMed

Zirin, Jonathan; Perrimon, Norbert

2010-12-01

Originally identified as a response to starvation in yeast, autophagy is now understood to fulfill a variety of roles in higher eukaryotes, from the maintenance of cellular homeostasis to the cellular response to stress, starvation, and infection. Although genetics and biochemical studies in yeast have identified many components involved in autophagy, the findings that some of the essential components of the yeast pathway are missing in higher organisms underscore the need to study autophagy in more complex systems. This review focuses on the use of the fruitfly, Drosophila melanogaster as a model system for analysis of autophagy. Drosophila is an organism well-suited for genetic analysis and represents an intermediate between yeast and mammals with respect to conservation of the autophagy machinery. Furthermore, the complex biology and physiology of Drosophila presents an opportunity to model human diseases in a tissue specific and analogous context.

The Mini-Chromosome Maintenance (Mcm) Complexes Interact with DNA Polymerase α-Primase and Stimulate Its Ability to Synthesize RNA Primers

PubMed Central

You, Zhiying; De Falco, Mariarosaria; Kamada, Katsuhiko; Pisani, Francesca M.; Masai, Hisao

2013-01-01

The Mini-chromosome maintenance (Mcm) proteins are essential as central components for the DNA unwinding machinery during eukaryotic DNA replication. DNA primase activity is required at the DNA replication fork to synthesize short RNA primers for DNA chain elongation on the lagging strand. Although direct physical and functional interactions between helicase and primase have been known in many prokaryotic and viral systems, potential interactions between helicase and primase have not been explored in eukaryotes. Using purified Mcm and DNA primase complexes, a direct physical interaction is detected in pull-down assays between the Mcm2∼7 complex and the hetero-dimeric DNA primase composed of the p48 and p58 subunits. The Mcm4/6/7 complex co-sediments with the primase and the DNA polymerase α-primase complex in glycerol gradient centrifugation and forms a Mcm4/6/7-primase-DNA ternary complex in gel-shift assays. Both the Mcm4/6/7 and Mcm2∼7 complexes stimulate RNA primer synthesis by DNA primase in vitro. However, primase inhibits the Mcm4/6/7 helicase activity and this inhibition is abolished by the addition of competitor DNA. In contrast, the ATP hydrolysis activity of Mcm4/6/7 complex is not affected by primase. Mcm and primase proteins mutually stimulate their DNA-binding activities. Our findings indicate that a direct physical interaction between primase and Mcm proteins may facilitate priming reaction by the former protein, suggesting that efficient DNA synthesis through helicase-primase interactions may be conserved in eukaryotic chromosomes. PMID:23977294

Operation and maintenance results from ISFOC CPV plants

NASA Astrophysics Data System (ADS)

Gil, Eduardo; Martinez, María; de la Rubia, Oscar

2017-09-01

The analysis of field operation and maintenance data collected during a period of over eight years, from CPV installations consisting of three different CPV technologies (including second generation of one of these technologies), has allowed us to get valuable information about the long-term degradation of the CPV systems. Through the study of the maintenance control ratio previously defined and by applying the root cause analysis methodology, the components responsible for the most unplanned interventions for each technology were identified. Focusing maintenance efforts on these components, a reduction of the unplanned interventions and the total cost of maintenance has been achieved over the years. Therefore, the deployment of an effective maintenance plan, identifying critical components, is essential to minimize the risk for investors and maximize the CPV power plants lifetime and energy output, increasing the availability of CPV installations, boosting market confidence in CPV systems.

State-dependent physiological maintenance in a long-lived ectotherm, the painted turtle (Chrysemys picta).

PubMed

Schwanz, Lisa; Warner, Daniel A; McGaugh, Suzanne; Di Terlizzi, Roberta; Bronikowski, Anne

2011-01-01

Energy allocation among somatic maintenance, reproduction and growth varies not only among species, but among individuals according to states such as age, sex and season. Little research has been conducted on the somatic (physiological) maintenance of long-lived organisms, particularly ectotherms such as reptiles. In this study, we examined sex differences and age- and season-related variation in immune function and DNA repair efficiency in a long-lived reptile, the painted turtle (Chrysemys picta). Immune components tended to be depressed during hibernation, in winter, compared with autumn or spring. Increased heterophil count during hibernation provided the only support for winter immunoenhancement. In juvenile and adult turtles, we found little evidence for senescence in physiological maintenance, consistent with predictions for long-lived organisms. Among immune components, swelling in response to phytohemagglutinin (PHA) and control injection increased with age, whereas basophil count decreased with age. Hatchling turtles had reduced basophil counts and natural antibodies, indicative of an immature immune system, but demonstrated higher DNA repair efficiency than older turtles. Reproductively mature turtles had reduced lymphocytes compared with juvenile turtles in the spring, presumably driven by a trade-off between maintenance and reproduction. Sex had little influence on physiological maintenance. These results suggest that components of physiological maintenance are modulated differentially according to individual state and highlight the need for more research on the multiple components of physiological maintenance in animals of variable states.

An exercise trial for wheelchair users: Project Workout on Wheels

PubMed Central

Froehlich-Grobe, Katherine; Aaronson, Lauren S.; Washburn, Richard A.; Little, Todd D.; Lee, Jaehoon; Nary, Dorothy E.; VanSciver, Angela; Nesbitt, Jill; Norman, Sarah E.

2011-01-01

There is growing interest in promoting health for people with disabilities, yet evidence regarding community-based interventions is sparse. This paper describes the design details of a randomized controlled trial (RCT) that will test the effectiveness of a multi-component behaviorally-based, intervention to promote exercise adoption (over 6 months) and maintenance (up to one year) among wheelchair users and includes descriptive data on participant characteristics at baseline. Participants were randomly assigned to either a staff-supported intervention group or a self-guided comparison group. The primary study aim is to assess the effectiveness of the multi-component behaviorally-based intervention for promoting physical activity adoption and maintenance. The RCT will also assess the physical and psychosocial effects of the intervention and the complex interplay of factors that influence the effectiveness of the intervention. Therefore, the primary outcome derives from participant reports of weekly exercise (type, frequency, duration) over 52 weeks. Secondary outcomes collected on four occasions (baseline, 3 months, 6 months, 12 months) included physiological outcomes (VO2 peak, strength), disability-related outcomes (pain, fatigue, participation), and psychosocial outcomes (exercise self-efficacy, exercise barriers, quality of life, depression, mood). This study will provide evidence regarding the effectiveness of a multi-component behaviorally-based intervention for promoting exercise adoption among people with mobility impairments that necessitate wheelchair use. PMID:22101206

SLR2000: a microlaser-based single photoelectron satellite laser ranging system

NASA Technical Reports Server (NTRS)

Degnan, John J.; McGarry, Jan F.

1998-01-01

SLR2000 is an autonomous and eyesafe satellite laser ranging (SLR) station with an expected single shot range precision of about one centimeter and a normal point (time-averaged) precision better than 3 mm. The system wil provide continuous 24 hour tracking coverage for a constellation of over twenty artificial satellites. Replication costs are expected to be roughly an order of magnitude less than current operational systems, and the system will be about 75% less expensive to operate and maintain relative to manned systems. Computer simulations have predicted a daylight tracking capability to GPS and lower satellites with telescope apertures of 40 cm and have demonstrated the ability of our current autotracking algorithm to extract mean signal strengths below .001 photoelectrons per pulse from daytime background noise. The dominant cost driver in present SLR systems is the onsite and central infrastructure manpower required to operate the system, to service and maintain the complex subsystems, and to ensure that the transmitted laser beam is not a hazard to onsite personnel or to overflying aircraft. To keep development, fabrication, and maintenance costs at a minimum, we adopted the following design philosophies: (1) use off the shelf commercial components wherever possible; this allows rapid component replacement and "outsourcing" of engineering support; (2) use smaller telescopes (less than 50 cm) since this constrains the cost, size, and weight of the telescope and tracking mount; and (3) for low maintenance and failsafe reliability, choose simple versus complex technical approaches and, where possible, use passive techniques and components rather than active ones. Adherence to these philosophies has led to the SLR2000 design described here.

CTC1-STN1 coordinates G- and C-strand synthesis to regulate telomere length.

PubMed

Gu, Peili; Jia, Shuting; Takasugi, Taylor; Smith, Eric; Nandakumar, Jayakrishnan; Hendrickson, Eric; Chang, Sandy

2018-05-17

Coats plus (CP) is a rare autosomal recessive disorder caused by mutations in CTC1, a component of the CST (CTC1, STN1, and TEN1) complex important for telomere length maintenance. The molecular basis of how CP mutations impact upon telomere length remains unclear. The CP CTC1 L1142H mutation has been previously shown to disrupt telomere maintenance. In this study, we used CRISPR/Cas9 to engineer this mutation into both alleles of HCT116 and RPE cells to demonstrate that CTC1:STN1 interaction is required to repress telomerase activity. CTC1 L1142H interacts poorly with STN1, leading to telomerase-mediated telomere elongation. Impaired interaction between CTC1 L1142H :STN1 and DNA Pol-α results in increased telomerase recruitment to telomeres and further telomere elongation, revealing that C:S binding to DNA Pol-α is required to fully repress telomerase activity. CP CTC1 mutants that fail to interact with DNA Pol-α resulted in loss of C-strand maintenance and catastrophic telomere shortening. Our findings place the CST complex as an important regulator of both G-strand extensions by telomerase and C-strand synthesis by DNA Pol-α. © 2018 The Authors. Aging Cell published by the Anatomical Society and John Wiley & Sons Ltd.

Maintenance Business Plans.

ERIC Educational Resources Information Center

Adams, Matt

2002-01-01

Discusses maintenance business plans, statements which provide accountability for facilities maintenance organizations' considerable budgets. Discusses the plan's components: statement of plan objectives, macro and detailed description of the facility assets, maintenance function descriptions, description of key performance indicators, milestone…

The development and application of composite complexity models and a relative complexity metric in a software maintenance environment

NASA Technical Reports Server (NTRS)

Hops, J. M.; Sherif, J. S.

1994-01-01

A great deal of effort is now being devoted to the study, analysis, prediction, and minimization of software maintenance expected cost, long before software is delivered to users or customers. It has been estimated that, on the average, the effort spent on software maintenance is as costly as the effort spent on all other software costs. Software design methods should be the starting point to aid in alleviating the problems of software maintenance complexity and high costs. Two aspects of maintenance deserve attention: (1) protocols for locating and rectifying defects, and for ensuring that noe new defects are introduced in the development phase of the software process; and (2) protocols for modification, enhancement, and upgrading. This article focuses primarily on the second aspect, the development of protocols to help increase the quality and reduce the costs associated with modifications, enhancements, and upgrades of existing software. This study developed parsimonious models and a relative complexity metric for complexity measurement of software that were used to rank the modules in the system relative to one another. Some success was achieved in using the models and the relative metric to identify maintenance-prone modules.

Solving complex maintenance planning optimization problems using stochastic simulation and multi-criteria fuzzy decision making

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

Tahvili, Sahar; Österberg, Jonas; Silvestrov, Sergei

One of the most important factors in the operations of many cooperations today is to maximize profit and one important tool to that effect is the optimization of maintenance activities. Maintenance activities is at the largest level divided into two major areas, corrective maintenance (CM) and preventive maintenance (PM). When optimizing maintenance activities, by a maintenance plan or policy, we seek to find the best activities to perform at each point in time, be it PM or CM. We explore the use of stochastic simulation, genetic algorithms and other tools for solving complex maintenance planning optimization problems in terms ofmore » a suggested framework model based on discrete event simulation.« less

Mutations in CTC1, Encoding the CTS Telomere Maintenance Complex Component 1, Cause Cerebroretinal Microangiopathy with Calcifications and Cysts

PubMed Central

Polvi, Anne; Linnankivi, Tarja; Kivelä, Tero; Herva, Riitta; Keating, James P.; Mäkitie, Outi; Pareyson, Davide; Vainionpää, Leena; Lahtinen, Jenni; Hovatta, Iiris; Pihko, Helena; Lehesjoki, Anna-Elina

2012-01-01

Cerebroretinal microangiopathy with calcifications and cysts (CRMCC) is a rare multisystem disorder characterized by extensive intracranial calcifications and cysts, leukoencephalopathy, and retinal vascular abnormalities. Additional features include poor growth, skeletal and hematological abnormalities, and recurrent gastrointestinal bleedings. Autosomal-recessive inheritance has been postulated. The pathogenesis of CRMCC is unknown, but its phenotype has key similarities with Revesz syndrome, which is caused by mutations in TINF2, a gene encoding a member of the telomere protecting shelterin complex. After a whole-exome sequencing approach in four unrelated individuals with CRMCC, we observed four recessively inherited compound heterozygous mutations in CTC1, which encodes the CTS telomere maintenance complex component 1. Sanger sequencing revealed seven more compound heterozygous mutations in eight more unrelated affected individuals. Two individuals who displayed late-onset cerebral findings, a normal fundus appearance, and no systemic findings did not have CTC1 mutations, implying that systemic findings are an important indication for CTC1 sequencing. Of the 11 mutations identified, four were missense, one was nonsense, two resulted in in-frame amino acid deletions, and four were short frameshift-creating deletions. All but two affected individuals were compound heterozygous for a missense mutation and a frameshift or nonsense mutation. No individuals with two frameshift or nonsense mutations were identified, which implies that severe disturbance of CTC1 function from both alleles might not be compatible with survival. Our preliminary functional experiments did not show evidence of severely affected telomere integrity in the affected individuals. Therefore, determining the underlying pathomechanisms associated with deficient CTC1 function will require further studies. PMID:22387016

Advanced software development workstation project: Engineering scripting language. Graphical editor

NASA Technical Reports Server (NTRS)

1992-01-01

Software development is widely considered to be a bottleneck in the development of complex systems, both in terms of development and in terms of maintenance of deployed systems. Cost of software development and maintenance can also be very high. One approach to reducing costs and relieving this bottleneck is increasing the reuse of software designs and software components. A method for achieving such reuse is a software parts composition system. Such a system consists of a language for modeling software parts and their interfaces, a catalog of existing parts, an editor for combining parts, and a code generator that takes a specification and generates code for that application in the target language. The Advanced Software Development Workstation is intended to be an expert system shell designed to provide the capabilities of a software part composition system.

Failure: A Source of Progress in Maintenance and Design

NASA Astrophysics Data System (ADS)

Chaïb, R.; Taleb, M.; Benidir, M.; Verzea, I.; Bellaouar, A.

This approach, allows using the failure as a source of progress in maintenance and design to detect the most critical components in equipment, to determine the priority order maintenance actions to lead and direct the exploitation procedure towards the most penalizing links in this equipment, even define the necessary changes and recommendations for future improvement. Thus, appreciate the pathological behaviour of the material and increase its availability, even increase its lifespan and improve its future design. In this context and in the light of these points, the failures are important in managing the maintenance function. Indeed, it has become important to understand the phenomena of failure and degradation of equipments in order to establish an appropriate maintenance policy for the rational use of mechanical components and move to the practice of proactive maintenance [1], do maintenance at the design [2].

High Concentration Standard Aerosol Generator.

DTIC Science & Technology

1985-07-31

Noncommercial Components .. .. ........ A-1 B. Maintenance Instructions and material Properties of Purchased Components . .. .. .. ... . . . . . . B-1...tration (if a lower flow or a wider size distribution is acceptable and 2) precautions and suggestions for use of different aerosol materials . Additional...details of the system (including shop drawings, 𔃻i4t lists of materials , and maintenance of commercially available components) are given in

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

Gonzalez Anez, Francisco

This paper presents two development projects (STARMATE and VIRMAN) focused on supporting training on maintenance. Both projects aim at specifying, designing, developing, and demonstrating prototypes allowing computer guided maintenance of complex mechanical elements using Augmented and Virtual Reality techniques. VIRMAN is a Spanish development project. The objective is to create a computer tool for maintenance training course elaborations and training delivery based on 3D virtual reality models of complex components. The training delivery includes 3D record displays on maintenance procedures with all complementary information for intervention understanding. Users are requested to perform the maintenance intervention trying to follow up themore » procedure. Users can be evaluated about the level of knowledge achieved. Instructors can check the evaluation records left during the training sessions. VIRMAN is simple software supported by a regular computer and can be used in an Internet framework. STARMATE is a forward step in the area of virtual reality. STARMATE is a European Commission project in the frame of 'Information Societies Technologies'. A consortium of five companies and one research institute shares their expertise in this new technology. STARMATE provides two main functionalities (1) user assistance for achieving assembly/de-assembly and following maintenance procedures, and (2) workforce training. The project relies on Augmented Reality techniques, which is a growing area in Virtual Reality research. The idea of Augmented Reality is to combine a real scene, viewed by the user, with a virtual scene, generated by a computer, augmenting the reality with additional information. The user interface is see-through goggles, headphones, microphone and an optical tracking system. All these devices are integrated in a helmet connected with two regular computers. The user has his hands free for performing the maintenance intervention and he can navigate in the virtual world thanks to a voice recognition system and a virtual pointing device. The maintenance work is guided with audio instructions, 2D and 3D information are directly displayed into the user's goggles: There is a position-tracking system that allows 3D virtual models to be displayed in the real counterpart positions independently of the user allocation. The user can create his own virtual environment, placing the information required wherever he wants. The STARMATE system is applicable to a large variety of real work situations. (author)« less

A leading edge heating array and a flat surface heating array - operation, maintenance and repair manual

NASA Technical Reports Server (NTRS)

1975-01-01

A general description of the leading edge/flat surface heating array is presented along with its components, assembly instructions, installation instructions, operation procedures, maintenance instructions, repair procedures, schematics, spare parts lists, engineering drawings of the array, and functional acceptance test log sheets. The proper replacement of components, correct torque values, step-by-step maintenance instructions, and pretest checkouts are described.

A measure for objects clustering in principal component analysis biplot: A case study in inter-city buses maintenance cost data

NASA Astrophysics Data System (ADS)

Ginanjar, Irlandia; Pasaribu, Udjianna S.; Indratno, Sapto W.

2017-03-01

This article presents the application of the principal component analysis (PCA) biplot for the needs of data mining. This article aims to simplify and objectify the methods for objects clustering in PCA biplot. The novelty of this paper is to get a measure that can be used to objectify the objects clustering in PCA biplot. Orthonormal eigenvectors, which are the coefficients of a principal component model representing an association between principal components and initial variables. The existence of the association is a valid ground to objects clustering based on principal axes value, thus if m principal axes used in the PCA, then the objects can be classified into 2m clusters. The inter-city buses are clustered based on maintenance costs data by using two principal axes PCA biplot. The buses are clustered into four groups. The first group is the buses with high maintenance costs, especially for lube, and brake canvass. The second group is the buses with high maintenance costs, especially for tire, and filter. The third group is the buses with low maintenance costs, especially for lube, and brake canvass. The fourth group is buses with low maintenance costs, especially for tire, and filter.

Gravitational and Dynamic Components of Muscle Torque Underlie Tonic and Phasic Muscle Activity during Goal-Directed Reaching.

PubMed

Olesh, Erienne V; Pollard, Bradley S; Gritsenko, Valeriya

2017-01-01

Human reaching movements require complex muscle activations to produce the forces necessary to move the limb in a controlled manner. How gravity and the complex kinetic properties of the limb contribute to the generation of the muscle activation pattern by the central nervous system (CNS) is a long-standing and controversial question in neuroscience. To tackle this issue, muscle activity is often subdivided into static and phasic components. The former corresponds to posture maintenance and transitions between postures. The latter corresponds to active movement production and the compensation for the kinetic properties of the limb. In the present study, we improved the methodology for this subdivision of muscle activity into static and phasic components by relating them to joint torques. Ten healthy subjects pointed in virtual reality to visual targets arranged to create a standard center-out reaching task in three dimensions. Muscle activity and motion capture data were synchronously collected during the movements. The motion capture data were used to calculate postural and dynamic components of active muscle torques using a dynamic model of the arm with 5 degrees of freedom. Principal Component Analysis (PCA) was then applied to muscle activity and the torque components, separately, to reduce the dimensionality of the data. Muscle activity was also reconstructed from gravitational and dynamic torque components. Results show that the postural and dynamic components of muscle torque represent a significant amount of variance in muscle activity. This method could be used to define static and phasic components of muscle activity using muscle torques.

Gravitational and Dynamic Components of Muscle Torque Underlie Tonic and Phasic Muscle Activity during Goal-Directed Reaching

PubMed Central

Olesh, Erienne V.; Pollard, Bradley S.; Gritsenko, Valeriya

2017-01-01

Human reaching movements require complex muscle activations to produce the forces necessary to move the limb in a controlled manner. How gravity and the complex kinetic properties of the limb contribute to the generation of the muscle activation pattern by the central nervous system (CNS) is a long-standing and controversial question in neuroscience. To tackle this issue, muscle activity is often subdivided into static and phasic components. The former corresponds to posture maintenance and transitions between postures. The latter corresponds to active movement production and the compensation for the kinetic properties of the limb. In the present study, we improved the methodology for this subdivision of muscle activity into static and phasic components by relating them to joint torques. Ten healthy subjects pointed in virtual reality to visual targets arranged to create a standard center-out reaching task in three dimensions. Muscle activity and motion capture data were synchronously collected during the movements. The motion capture data were used to calculate postural and dynamic components of active muscle torques using a dynamic model of the arm with 5 degrees of freedom. Principal Component Analysis (PCA) was then applied to muscle activity and the torque components, separately, to reduce the dimensionality of the data. Muscle activity was also reconstructed from gravitational and dynamic torque components. Results show that the postural and dynamic components of muscle torque represent a significant amount of variance in muscle activity. This method could be used to define static and phasic components of muscle activity using muscle torques. PMID:29018339

Performance of Water Recirculation Loop Maintenance Components for the Advanced Spacesuit Water Membrane Evaporator

NASA Technical Reports Server (NTRS)

Rector, Tony; Peyton, Barbara M.; Steele, John W.; Makinen, Janice; Bue, Grant C.; Campbell, Colin

2014-01-01

Water loop maintenance components to maintain the water quality of the Advanced Spacesuit Water Membrane Evaporation (SWME) water recirculation loop have undergone a comparative performance evaluation with a second SWME water recirculation loop with no water quality maintenance. Results show the benefits of periodic water maintenance. The SWME is a heat rejection device under development at the NASA Johnson Space Center to perform thermal control for advanced spacesuits. One advantage to this technology is the potential for a significantly greater degree of tolerance to contamination when compared to the existing Sublimator technology. The driver for the evaluation of water recirculation maintenance components was to further enhance this advantage through the leveraging of fluid loop management lessons learned from the International Space Station (ISS). A bed design that was developed for a UTAS military application, and considered for a potential ISS application with the Urine Processor Assembly, provided a low pressure drop means for water maintenance in a recirculation loop. The bed design is coupled with high capacity ion exchange resins, organic adsorbents, and a cyclic methodology developed for the Extravehicular Mobility Unit (EMU) Transport Water loop. The maintenance cycle included the use of a biocide delivery component developed for ISS to introduce a biocide in a microgravity compatible manner for the Internal Active Thermal Control System (IATCS). The leveraging of these water maintenance technologies to the SWME recirculation loop is a unique demonstration of applying the valuable lessons learned on the ISS to the next generation of manned spaceflight Environmental Control and Life Support System (ECLSS) hardware.

Performance of Water Recirculation Loop Maintenance Components for the Advanced Spacesuit Water Membrane Evaporator

NASA Technical Reports Server (NTRS)

Rector, Tony; Peyton, Barbara M.; Steele, John W.; Makinen, Janice; Bue, Grant C.; Campbell, Colin

2014-01-01

Water loop maintenance components to maintain the water quality of the Advanced Spacesuit Water Membrane Evaporation (SWME) water recirculation loop have undergone a comparative performance evaluation with a recirculating control loop which had no water quality maintenance. Results show that periodic water maintenance can improve performance of the SWME. The SWME is a heat rejection device under development at the NASA Johnson Space Center to perform thermal control for advanced spacesuits. One advantage of this technology is the potential for a significantly greater degree of tolerance to contamination when compared to the existing sublimator technology. The driver for the evaluation of water recirculation maintenance components was to enhance the robustness of the SWME through the leveraging of fluid loop management lessons learned from the International Space Station (ISS). A patented bed design that was developed for a United Technologies Aerospace System military application provided a low pressure drop means for water maintenance in the SWME recirculation loop. The bed design is coupled with high capacity ion exchange resins, organic adsorbents, and a cyclic methodology developed for the Extravehicular Mobility Unit (EMU) Transport Water loop. The maintenance cycle included the use of a biocide delivery component developed for the ISS to introduce a biocide in a microgravity compatible manner for the Internal Active Thermal Control System (IATCS). The leveraging of these water maintenance technologies to the SWME recirculation loop is a unique demonstration of applying the valuable lessons learned on the ISS to the next generation of manned spaceflight Environmental Control and Life Support System (ECLSS) hardware.

Activation of translation complex eIF4F is essential for the genesis and maintenance of the malignant phenotype in human mammary epithelial cells.

PubMed

Avdulov, Svetlana; Li, Shunan; Michalek, Van; Burrichter, David; Peterson, Mark; Perlman, David M; Manivel, J Carlos; Sonenberg, Nahum; Yee, Douglas; Bitterman, Peter B; Polunovsky, Vitaly A

2004-06-01

Common human malignancies acquire derangements of the translation initiation complex, eIF4F, but their functional significance is unknown. Hypophosphorylated 4E-BP proteins negatively regulate eIF4F assembly by sequestering its mRNA cap binding component eIF4E, whereas hyperphosphorylation abrogates this function. We found that breast carcinoma cells harbor increases in the eIF4F constituent eIF4GI and hyperphosphorylation of 4E-BP1 which are two alterations that activate eIF4F assembly. Ectopic expression of eIF4E in human mammary epithelial cells enabled clonal expansion and anchorage-independent growth. Transfer of 4E-BP1 phosphorylation site mutants into breast carcinoma cells suppressed their tumorigenicity, whereas loss of these 4E-BP1 phosphorylation site mutants accompanied spontaneous reversion to a malignant phenotype. Thus, eIF4F activation is an essential component of the malignant phenotype in breast carcinoma.

Relationship of slow and rapid EEG components of CAP to ASDA arousals in normal sleep.

PubMed

Parrino, L; Smerieri, A; Rossi, M; Terzano, M G

2001-12-15

Besides arousals (according to the ASDA definition), sleep contains also K-complexes and delta bursts which, in spite of their sleep-like features, are endowed with activating effects on autonomic functions. The link between phasic delta activities and enhancement of vegetative functions indicates the possibility of physiological activation without sleep disruption (i.e., arousal without awakening). A functional connection seems to include slow (K-complexes and delta bursts) and rapid (arousals) EEG events within the comprehensive term of activating complexes. CAP (cyclic alternating pattern) is the spontaneous EEG rhythm that ties both slow and rapid activating complexes together during NREM sleep. The present study aims at exploring the relationship between arousals and CAP components in a selected sample of healthy sleepers. Polysomnographic analysis according to the scoring rules for sleep stages and arousals. CAP analysis included also tabulation of subtypes A1 (slow EEG activating complexes), A2 and A3 (activating complexes with fast EEG components). 40 sleep-lab accomplished recordings. Healthy subjects belonging to a wide age range (38 +/- 20 yrs.). N/A. Of all the arousals occurring in NREM sleep, 87% were inserted within CAP. Subtypes A2 and A3 of CAP corresponded strikingly with arousals (r=0.843; p<0.0001), while no statistical relationship emerged when arousals were matched with subtypes A1 of CAP. Subtypes A1 instead correlated positively with the percentages of deep sleep (r=0.366; p<0.02). The CAP subtype classification encompasses both the process of sleep maintenance (subtypes A1) and sleep fragmentation (subtypes A2 and A3), and provides a periodicity dimension to the activating events of NREM sleep.

EMD-Based Methodology for the Identification of a High-Speed Train Running in a Gear Operating State.

PubMed

Bustos, Alejandro; Rubio, Higinio; Castejón, Cristina; García-Prada, Juan Carlos

2018-03-06

An efficient maintenance is a key consideration in systems of railway transport, especially in high-speed trains, in order to avoid accidents with catastrophic consequences. In this sense, having a method that allows for the early detection of defects in critical elements, such as the bogie mechanical components, is a crucial for increasing the availability of rolling stock and reducing maintenance costs. The main contribution of this work is the proposal of a methodology that, based on classical signal processing techniques, provides a set of parameters for the fast identification of the operating state of a critical mechanical system. With this methodology, the vibratory behaviour of a very complex mechanical system is characterised, through variable inputs, which will allow for the detection of possible changes in the mechanical elements. This methodology is applied to a real high-speed train in commercial service, with the aim of studying the vibratory behaviour of the train (specifically, the bogie) before and after a maintenance operation. The results obtained with this methodology demonstrated the usefulness of the new procedure and allowed for the disclosure of reductions between 15% and 45% in the spectral power of selected Intrinsic Mode Functions (IMFs) after the maintenance operation.

EMD-Based Methodology for the Identification of a High-Speed Train Running in a Gear Operating State

PubMed Central

García-Prada, Juan Carlos

2018-01-01

An efficient maintenance is a key consideration in systems of railway transport, especially in high-speed trains, in order to avoid accidents with catastrophic consequences. In this sense, having a method that allows for the early detection of defects in critical elements, such as the bogie mechanical components, is a crucial for increasing the availability of rolling stock and reducing maintenance costs. The main contribution of this work is the proposal of a methodology that, based on classical signal processing techniques, provides a set of parameters for the fast identification of the operating state of a critical mechanical system. With this methodology, the vibratory behaviour of a very complex mechanical system is characterised, through variable inputs, which will allow for the detection of possible changes in the mechanical elements. This methodology is applied to a real high-speed train in commercial service, with the aim of studying the vibratory behaviour of the train (specifically, the bogie) before and after a maintenance operation. The results obtained with this methodology demonstrated the usefulness of the new procedure and allowed for the disclosure of reductions between 15% and 45% in the spectral power of selected Intrinsic Mode Functions (IMFs) after the maintenance operation. PMID:29509690

Exposure to Nickel, Chromium, or Cadmium Causes Distinct Changes in the Gene Expression Patterns of a Rat Liver Derived Cell Line

DTIC Science & Technology

2011-11-16

protein A (Rpa2), the minichromosome maintenance complex component genes which encode helicases, DNA ligase (Lig1), DNA polymerase e ( Pole and Pole2...and DNA polymerase d ( Pold1 and Pold2 ) are all up-regulated as a result of exposure to chromium (Figure 6), suggesting that there is an increase in...Exposure to Nickel, Chromium, or Cadmium Causes Distinct Changes in the Gene Expression Patterns of a Rat Liver Derived Cell Line Matthew G

Functional connectivity supporting the selective maintenance of feature-location binding in visual working memory

PubMed Central

Takahama, Sachiko; Saiki, Jun

2014-01-01

Information on an object's features bound to its location is very important for maintaining object representations in visual working memory. Interactions with dynamic multi-dimensional objects in an external environment require complex cognitive control, including the selective maintenance of feature-location binding. Here, we used event-related functional magnetic resonance imaging to investigate brain activity and functional connectivity related to the maintenance of complex feature-location binding. Participants were required to detect task-relevant changes in feature-location binding between objects defined by color, orientation, and location. We compared a complex binding task requiring complex feature-location binding (color-orientation-location) with a simple binding task in which simple feature-location binding, such as color-location, was task-relevant and the other feature was task-irrelevant. Univariate analyses showed that the dorsolateral prefrontal cortex (DLPFC), hippocampus, and frontoparietal network were activated during the maintenance of complex feature-location binding. Functional connectivity analyses indicated cooperation between the inferior precentral sulcus (infPreCS), DLPFC, and hippocampus during the maintenance of complex feature-location binding. In contrast, the connectivity for the spatial updating of simple feature-location binding determined by reanalyzing the data from Takahama et al. (2010) demonstrated that the superior parietal lobule (SPL) cooperated with the DLPFC and hippocampus. These results suggest that the connectivity for complex feature-location binding does not simply reflect general memory load and that the DLPFC and hippocampus flexibly modulate the dorsal frontoparietal network, depending on the task requirements, with the infPreCS involved in the maintenance of complex feature-location binding and the SPL involved in the spatial updating of simple feature-location binding. PMID:24917833

Functional connectivity supporting the selective maintenance of feature-location binding in visual working memory.

PubMed

Takahama, Sachiko; Saiki, Jun

2014-01-01

Information on an object's features bound to its location is very important for maintaining object representations in visual working memory. Interactions with dynamic multi-dimensional objects in an external environment require complex cognitive control, including the selective maintenance of feature-location binding. Here, we used event-related functional magnetic resonance imaging to investigate brain activity and functional connectivity related to the maintenance of complex feature-location binding. Participants were required to detect task-relevant changes in feature-location binding between objects defined by color, orientation, and location. We compared a complex binding task requiring complex feature-location binding (color-orientation-location) with a simple binding task in which simple feature-location binding, such as color-location, was task-relevant and the other feature was task-irrelevant. Univariate analyses showed that the dorsolateral prefrontal cortex (DLPFC), hippocampus, and frontoparietal network were activated during the maintenance of complex feature-location binding. Functional connectivity analyses indicated cooperation between the inferior precentral sulcus (infPreCS), DLPFC, and hippocampus during the maintenance of complex feature-location binding. In contrast, the connectivity for the spatial updating of simple feature-location binding determined by reanalyzing the data from Takahama et al. (2010) demonstrated that the superior parietal lobule (SPL) cooperated with the DLPFC and hippocampus. These results suggest that the connectivity for complex feature-location binding does not simply reflect general memory load and that the DLPFC and hippocampus flexibly modulate the dorsal frontoparietal network, depending on the task requirements, with the infPreCS involved in the maintenance of complex feature-location binding and the SPL involved in the spatial updating of simple feature-location binding.

The engine maintenance scheduling by using reliability centered maintenance method and the identification of 5S application in PT. XYZ

NASA Astrophysics Data System (ADS)

Sembiring, N.; Panjaitan, N.; Saragih, A. F.

2018-02-01

PT. XYZ is a manufacturing company that produces fresh fruit bunches (FFB) to Crude Palm Oil (CPO) and Palm Kernel Oil (PKO). PT. XYZ consists of six work stations: receipt station, sterilizing station, thressing station, pressing station, clarification station, and kernelery station. So far, the company is still implementing corrective maintenance maintenance system for production machines where the machine repair is done after damage occurs. Problems at PT. XYZ is the absence of scheduling engine maintenance in a planned manner resulting in the engine often damaged which can disrupt the smooth production. Another factor that is the problem in this research is the kernel station environment that becomes less convenient for operators such as there are machines and equipment not used in the production area, slippery, muddy, scattered fibers, incomplete use of PPE, and lack of employee discipline. The most commonly damaged machine is in the seed processing station (kernel station) which is cake breaker conveyor machine. The solution of this problem is to propose a schedule plan for maintenance of the machine by using the method of reliability centered maintenance and also the application of 5S. The result of the application of Reliability Centered maintenance method is obtained four components that must be treated scheduled (time directed), namely: for bearing component is 37 days, gearbox component is 97 days, CBC pen component is 35 days and conveyor pedal component is 32 days While after identification the application of 5S obtained the proposed corporate environmental improvement measures in accordance with the principles of 5S where unused goods will be moved from the production area, grouping goods based on their use, determining the procedure of cleaning the production area, conducting inspection in the use of PPE, and making 5S slogans.

GMT azimuth bogie wheel-rail interface wear study

NASA Astrophysics Data System (ADS)

Teran, Jose; Lindh, Cory; Morgan, Chris; Manuel, Eric; Bigelow, Bruce C.; Burgett, William S.

2016-07-01

Performance of the GMT azimuth drive system is vital for the operation of the telescope and, as such, all components subject to wear at the drive interface merit a high level of scrutiny for achieving a proper balance between capital costs, maintenance costs, and the risk for downtime during planned and unplanned maintenance or replacement procedures. Of particular importance is the interface between the azimuth wheels and rail, as usage frequency is high, the full weight of the enclosure must be transferred through small patches of contact, and replacement of the rail would pose a greater logistical challenge than the replacement of smaller components such as bearings and gearmotors. This study investigates tradeoffs between various wheel-rail and roller-track interfaces, including performance, complexity, and anticipated wear considerations. First, a survey of railway and overhead crane industry literature is performed and general detailing recommendations are made to minimize wear and the risk of rolling contact fatigue. Second, Adams/VI-Rail is used to simulate lifetime wear of four specific configurations under consideration for the GMT azimuth wheel-rail interface; all studied configurations are shown to be viable, and their relative merits are discussed.

Spatial Variation in Host Feeding Patterns of Culex tarsalis and the Culex pipiens complex (Diptera: Culicidae) in California

PubMed Central

THIEMANN, T. C.; LEMENAGER, D. A.; KLUH, S.; CARROLL, B. D.; LOTHROP, H. D.; REISEN, W. K.

2012-01-01

West Nile virus (family Flaviviridae, genus Flavivirus, WNV) is now endemic in California across a variety of ecological regions that support a wide diversity of potential avian and mammalian host species. Because different avian hosts have varying competence for WNV, determining the blood-feeding patterns of Culex (Diptera: Culicidae) vectors is a key component in understanding the maintenance and amplification of the virus as well as tangential transmission to humans and horses. We investigated the blood-feeding patterns of Culex tarsalis Coquillett and members of the Culex pipiens L. complex from southern to northern California. Nearly 100 different host species were identified from 1,487 bloodmeals, by using the mitochondrial gene cytochrome c oxidase I (COI). Cx. tarsalis fed on a higher diversity of hosts and more frequently on nonhuman mammals than did the Cx. pipiens complex. Several WNV-competent host species, including house finch and house sparrow, were common bloodmeal sources for both vector species across several biomes and could account for WNV maintenance and amplification in these areas. Highly competent American crow, western scrub-jay and yellow-billed magpie also were fed upon often when available and are likely important as amplifying hosts for WNV in some areas. Neither species fed frequently on humans (Cx. pipiens complex [0.4%], Cx. tarsalis [0.2%]), but with high abundance, both species could serve as both enzootic and bridge vectors for WNV. PMID:22897051

Inner nuclear envelope protein SUN1 plays a prominent role in mammalian mRNA export.

PubMed

Li, Ping; Noegel, Angelika A

2015-11-16

Nuclear export of messenger ribonucleoproteins (mRNPs) through the nuclear pore complex (NPC) can be roughly classified into two forms: bulk and specific export, involving an nuclear RNA export factor 1 (NXF1)-dependent pathway and chromosome region maintenance 1 (CRM1)-dependent pathway, respectively. SUN proteins constitute the inner nuclear envelope component of the l I: nker of N: ucleoskeleton and C: ytoskeleton (LINC) complex. Here, we show that mammalian cells require SUN1 for efficient nuclear mRNP export. The results indicate that both SUN1 and SUN2 interact with heterogeneous nuclear ribonucleoprotein (hnRNP) F/H and hnRNP K/J. SUN1 depletion inhibits the mRNP export, with accumulations of both hnRNPs and poly(A)+RNA in the nucleus. Leptomycin B treatment indicates that SUN1 functions in mammalian mRNA export involving the NXF1-dependent pathway. SUN1 mediates mRNA export through its association with mRNP complexes via a direct interaction with NXF1. Additionally, SUN1 associates with the NPC through a direct interaction with Nup153, a nuclear pore component involved in mRNA export. Taken together, our results reveal that the inner nuclear envelope protein SUN1 has additional functions aside from being a central component of the LINC complex and that it is an integral component of the mammalian mRNA export pathway suggesting a model whereby SUN1 recruits NXF1-containing mRNP onto the nuclear envelope and hands it over to Nup153. © The Author(s) 2015. Published by Oxford University Press on behalf of Nucleic Acids Research.

Application of reliability-centered-maintenance to BWR ECCS motor operator valve performance

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

Feltus, M.A.; Choi, Y.A.

1993-01-01

This paper describes the application of reliability-centered maintenance (RCM) methods to plant probabilistic risk assessment (PRA) and safety analyses for four boiling water reactor emergency core cooling systems (ECCSs): (1) high-pressure coolant injection (HPCI); (2) reactor core isolation cooling (RCIC); (3) residual heat removal (RHR); and (4) core spray systems. Reliability-centered maintenance is a system function-based technique for improving a preventive maintenance program that is applied on a component basis. Those components that truly affect plant function are identified, and maintenance tasks are focused on preventing their failures. The RCM evaluation establishes the relevant criteria that preserve system function somore » that an RCM-focused approach can be flexible and dynamic.« less

Preliminary Analysis of ISS Maintenance History and Implications for Supportability of Future Missions

NASA Technical Reports Server (NTRS)

Watson, Kevin J.; Robbins, William W.

2004-01-01

The International Space Station (ISS) enables the study of supportability issues associated with long-duration human spaceflight. The ISS is a large, complex spacecraft that must be maintained by its crew. In contrast to the Space Shuttle Orbiter vehicle, but similar to spacecraft that will be component elements of future missions beyond low-Earth orbit, ISS does not return to the ground for servicing and provisioning of spares is severely constrained by transportation limits. Although significant technical support is provided by ground personnel, all hands-on maintenance tasks are performed by the crew. It is expected that future missions to distant destinations will be further limited by lack of resupply opportunities and will, eventually, become largely independent of ground support. ISS provides an opportunity to begin learning lessons that will enable future missions to be successful. Data accumulated over the first several years of ISS operations have been analyzed to gain a better understanding of maintenance-related workload. This analysis addresses both preventive and corrective maintenance and includes all U.S segment core systems. Systems and tasks that are major contributors to workload are identified. As further experience accrues, lessons will be learned that will influence future system designs so that they require less maintenance and, when maintenance is required, it can be performed more efficiently. By heeding the lessons of ISS it will be possible to identify system designs that should be more robust and point towards advances in both technology and design that will offer the greatest return on investment.

Optimal maintenance of a multi-unit system under dependencies

NASA Astrophysics Data System (ADS)

Sung, Ho-Joon

The availability, or reliability, of an engineering component greatly influences the operational cost and safety characteristics of a modern system over its life-cycle. Until recently, the reliance on past empirical data has been the industry-standard practice to develop maintenance policies that provide the minimum level of system reliability. Because such empirically-derived policies are vulnerable to unforeseen or fast-changing external factors, recent advancements in the study of topic on maintenance, which is known as optimal maintenance problem, has gained considerable interest as a legitimate area of research. An extensive body of applicable work is available, ranging from those concerned with identifying maintenance policies aimed at providing required system availability at minimum possible cost, to topics on imperfect maintenance of multi-unit system under dependencies. Nonetheless, these existing mathematical approaches to solve for optimal maintenance policies must be treated with caution when considered for broader applications, as they are accompanied by specialized treatments to ease the mathematical derivation of unknown functions in both objective function and constraint for a given optimal maintenance problem. These unknown functions are defined as reliability measures in this thesis, and theses measures (e.g., expected number of failures, system renewal cycle, expected system up time, etc.) do not often lend themselves to possess closed-form formulas. It is thus quite common to impose simplifying assumptions on input probability distributions of components' lifetime or repair policies. Simplifying the complex structure of a multi-unit system to a k-out-of-n system by neglecting any sources of dependencies is another commonly practiced technique intended to increase the mathematical tractability of a particular model. This dissertation presents a proposal for an alternative methodology to solve optimal maintenance problems by aiming to achieve the same end-goals as Reliability Centered Maintenance (RCM). RCM was first introduced to the aircraft industry in an attempt to bridge the gap between the empirically-driven and theory-driven approaches to establishing optimal maintenance policies. Under RCM, qualitative processes that enable the prioritizing of functions based on the criticality and influence would be combined with mathematical modeling to obtain the optimal maintenance policies. Where this thesis work deviates from RCM is its proposal to directly apply quantitative processes to model the reliability measures in optimal maintenance problem. First, Monte Carlo (MC) simulation, in conjunction with a pre-determined Design of Experiments (DOE) table, can be used as a numerical means of obtaining the corresponding discrete simulated outcomes of the reliability measures based on the combination of decision variables (e.g., periodic preventive maintenance interval, trigger age for opportunistic maintenance, etc.). These discrete simulation results can then be regressed as Response Surface Equations (RSEs) with respect to the decision variables. Such an approach to represent the reliability measures with continuous surrogate functions (i.e., the RSEs) not only enables the application of the numerical optimization technique to solve for optimal maintenance policies, but also obviates the need to make mathematical assumptions or impose over-simplifications on the structure of a multi-unit system for the sake of mathematical tractability. The applicability of the proposed methodology to a real-world optimal maintenance problem is showcased through its application to a Time Limited Dispatch (TLD) of Full Authority Digital Engine Control (FADEC) system. In broader terms, this proof-of-concept exercise can be described as a constrained optimization problem, whose objective is to identify the optimal system inspection interval that guarantees a certain level of availability for a multi-unit system. A variety of reputable numerical techniques were used to model the problem as accurately as possible, including algorithms for the MC simulation, imperfect maintenance model from quasi renewal processes, repair time simulation, and state transition rules. Variance Reduction Techniques (VRTs) were also used in an effort to enhance MC simulation efficiency. After accurate MC simulation results are obtained, the RSEs are generated based on the goodness-of-fit measure to yield as parsimonious model as possible to construct the optimization problem. Under the assumption of constant failure rate for lifetime distributions, the inspection interval from the proposed methodology was found to be consistent with the one from the common approach used in industry that leverages Continuous Time Markov Chain (CTMC). While the latter does not consider maintenance cost settings, the proposed methodology enables an operator to consider different types of maintenance cost settings, e.g., inspection cost, system corrective maintenance cost, etc., to result in more flexible maintenance policies. When the proposed methodology was applied to the same TLD of FADEC example, but under the more generalized assumption of strictly Increasing Failure Rate (IFR) for lifetime distribution, it was shown to successfully capture component wear-out, as well as the economic dependencies among the system components.

76 FR 9374 - Proposed Extension of Existing Information Collection; Examinations and Testing of Electrical...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-02-17

... related detached components; 75.800-4 Testing, examination and maintenance of circuit breakers; record; 75...-4 Testing, examination and maintenance of circuit breakers; record; 75.1001-1 Devices for..., testing, and maintenance; 77.800-2 Testing, examination and maintenance of circuit breakers; record; and...

ICD Complex Operations and Maintenance Plan

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

Gibson, P. L.

2007-06-25

This Operations and Maintenance (O&M) Plan describes how the Idaho National Laboratory (INL) conducts operations, winterization, and startup of the Idaho CERCLA Disposal Facility (ICDF) Complex. The ICDF Complex is the centralized INL facility responsible for the receipt, storage, treatment (as necessary), and disposal of INL Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) remediation waste.

Performance of Water Recirculation Loop Maintentance Components for the Advanced Spacesuit Water Membrane Evaporator

NASA Technical Reports Server (NTRS)

Rector, Tony; Peyton, Barbara; Steele, John W.; Bue, Grant C.; Campbell, Colin; Makinen, Janice

2014-01-01

Water loop maintenance components to maintain the water quality of the Advanced Spacesuit Water Membrane Evaporation (SWME) water recirculation loop have undergone a comparative performance evaluation with a second SWME water recirculation loop with no water quality maintenance. Results show the benefits of periodic water maintenance. The SWME is a heat rejection device under development at the NASA Johnson Space Center to perform thermal control for advanced spacesuits. One advantage to this technology is the potential for a significantly greater degree of tolerance to contamination when compared to the existing Sublimator technology. The driver for the evaluation of water recirculation maintenance components was to further enhance this advantage through the leveraging of fluid loop management lessonslearned from the International Space Station (ISS). A bed design that was developed for a UTAS military application, and considered for a potential ISS application with the Urine Processor Assembly, provided a low pressure drop means for water maintenance in a recirculation loop. The bed design is coupled with high capacity ion exchange resins, organic adsorbents, and a cyclic methodology developed for the Extravehicular Mobility Unit (EMU) Transport Water loop. The maintenance cycle included the use of a biocide delivery component developed for ISS to introduce a biocide in a microgravity-compatible manner for the Internal Active Thermal Control System (IATCS). The leveraging of these water maintenance technologies to the SWME recirculation loop is a unique demonstration of applying the valuable lessons learned on the ISS to the next generation of manned spaceflight Environmental Control and Life Support System (ECLSS) hardware.

Department of the Navy Justification of Estimates for Fiscal Year 1986 Submitted to Congress February 1985, Operation and Maintenance, Navy. Book 2

DTIC Science & Technology

1985-02-01

Range Missile Combatants (CGpCON, DDGFFG) 78 85 95 Mobile Logistics Force (AOE ,AE ,AOR,AO) 27 27 27 . ., Unit costs increase due to the mix of components...low- mix maintenance concept (less on-board maintenance) used on this class ship necessitates rework of these antennas % every four years. FY 1984 FY...4. Other 838 40 1,147 55 563 55 (Component mix changes each year) 7091 77--.-- --- o

The MBD7 complex promotes expression of methylated transgenes without significantly altering their methylation status

PubMed Central

Li, Dongming; Palanca, Ana Marie S; Won, So Youn; Gao, Lei; Feng, Ying; Vashisht, Ajay A; Liu, Li; Zhao, Yuanyuan; Liu, Xigang; Wu, Xiuyun; Li, Shaofang; Le, Brandon; Kim, Yun Ju; Yang, Guodong; Li, Shengben; Liu, Jinyuan; Wohlschlegel, James A; Guo, Hongwei; Mo, Beixin; Chen, Xuemei; Law, Julie A

2017-01-01

DNA methylation is associated with gene silencing in eukaryotic organisms. Although pathways controlling the establishment, maintenance and removal of DNA methylation are known, relatively little is understood about how DNA methylation influences gene expression. Here we identified a METHYL-CpG-BINDING DOMAIN 7 (MBD7) complex in Arabidopsis thaliana that suppresses the transcriptional silencing of two LUCIFERASE (LUC) reporters via a mechanism that is largely downstream of DNA methylation. Although mutations in components of the MBD7 complex resulted in modest increases in DNA methylation concomitant with decreased LUC expression, we found that these hyper-methylation and gene expression phenotypes can be genetically uncoupled. This finding, along with genome-wide profiling experiments showing minimal changes in DNA methylation upon disruption of the MBD7 complex, places the MBD7 complex amongst a small number of factors acting downstream of DNA methylation. This complex, however, is unique as it functions to suppress, rather than enforce, DNA methylation-mediated gene silencing. DOI: http://dx.doi.org/10.7554/eLife.19893.001 PMID:28452714

Zn2+ selectively stabilizes FdU-substituted DNA through a unique major groove binding motif

PubMed Central

Ghosh, Supratim; Salsbury, Freddie R.; Horita, David A.; Gmeiner, William H.

2011-01-01

We report, based on semi-empirical calculations, that Zn2+ binds duplex DNA containing consecutive FdU–dA base pairs in the major groove with distorted trigonal bipyramidal geometry. In this previously uncharacterized binding motif, O4 and F5 on consecutive FdU are axial ligands while three water molecules complete the coordination sphere. NMR spectroscopy confirmed Zn2+ complexation occurred with maintenance of base pairing while a slight hypsochromic shift in circular dichroism (CD) spectra indicated moderate structural distortion relative to B-form DNA. Zn2+ complexation inhibited ethidium bromide (EtBr) intercalation and stabilized FdU-substituted duplex DNA (ΔTm > 15°C). Mg2+ neither inhibited EtBr complexation nor had as strong of a stabilizing effect. DNA sequences that did not contain consecutive FdU were not stabilized by Zn2+. A lipofectamine preparation of the Zn2+–DNA complex displayed enhanced cytotoxicity toward prostate cancer cells relative to the individual components prepared as lipofectamine complexes indicating the potential utility of Zn2+–DNA complexes for cancer treatment. PMID:21296761

User's Guide for a Computerized Track Maintenance Simulation Cost Methodology

DOT National Transportation Integrated Search

1982-02-01

This User's Guide describes the simulation cost modeling technique developed for costing of maintenance operations of track and its component structures. The procedure discussed provides for separate maintenance cost entries to be associated with def...

Facilities available for biomedical science research in the public universities in Lagos, Nigeria.

PubMed

John, T A

2010-03-01

Across the world, basic medical scientists and physician scientists work on common platforms in state-of-the-arts laboratories doing translational research that occasionally results in bedside application. Biotechnology industries capitalise on useful findings for colossal profit.1 In Nigeria and the rest of Africa, biomedical science has not thrived and the contribution of publications to global high impact journals is low.2 This work investigated facilities available for modern biomedical research in Lagos public universities to extract culprit factors. The two public universities in Lagos, Nigeria were investigated by a cross sectional questionnaire survey of the technical staff manning biomedical science departments. They were asked about availability of 47 modern biomedical science research laboratory components such as cold room and microscopes and six research administration components such as director of research and grants administration. For convenient basic laboratory components such as autoclaves and balances, 50% responses indicated "well maintained and always functional" whereas for less convenient complex, high maintenance, state-of-the-arts equipment 19% responses indicated "well maintained and always functional." Respondents indicated that components of modern biomedical science research administration were 44% of expectation. The survey reveal a deficit in state-of the-arts research equipment and also a deficit in high maintenance, expensive equipment indicating that biomedical science in the investigated environment lacks the momentum of global trends and also lacks buoyant funding. In addition, administration supporting biomedical science is below expectation and may also account for the low contributions of research articles to global high impact journals.

Hybrid optical (freeform) components--functionalization of nonplanar optical surfaces by direct picosecond laser ablation.

PubMed

Kleindienst, Roman; Kampmann, Ronald; Stoebenau, Sebastian; Sinzinger, Stefan

2011-07-01

The performance of optical systems is typically improved by increasing the number of conventionally fabricated optical components (spheres, aspheres, and gratings). This approach is automatically connected to a system enlargement, as well as potentially higher assembly and maintenance costs. Hybrid optical freeform components can help to overcome this trade-off. They merge several optical functions within fewer but more complex optical surfaces, e.g., elements comprising shallow refractive/reflective and high-frequency diffractive structures. However, providing the flexibility and precision essential for their realization is one of the major challenges in the field of optical component fabrication. In this article we present tailored integrated machining techniques suitable for rapid prototyping as well as the fabrication of molding tools for low-cost mass replication of hybrid optical freeform components. To produce the different feature sizes with optical surface quality, we successively combine mechanical machining modes (ultraprecision micromilling and fly cutting) with precisely aligned direct picosecond laser ablation in an integrated fabrication approach. The fabrication accuracy and surface quality achieved by our integrated fabrication approach are demonstrated with profilometric measurements and experimental investigations of the optical performance.

Synaptonemal Complex Components Persist at Centromeres and Are Required for Homologous Centromere Pairing in Mouse Spermatocytes

PubMed Central

Kouznetsova, Anna; Scherthan, Harry; Höög, Christer; Dawson, Dean S.; Pezza, Roberto J.

2012-01-01

Recent studies in simple model organisms have shown that centromere pairing is important for ensuring high-fidelity meiotic chromosome segregation. However, this process and the mechanisms regulating it in higher eukaryotes are unknown. Here we present the first detailed study of meiotic centromere pairing in mouse spermatogenesis and link it with key events of the G2/metaphase I transition. In mouse we observed no evidence of the persistent coupling of centromeres that has been observed in several model organisms. We do however find that telomeres associate in non-homologous pairs or small groups in B type spermatogonia and pre-leptotene spermatocytes, and this association is disrupted by deletion of the synaptonemal complex component SYCP3. Intriguingly, we found that, in mid prophase, chromosome synapsis is not initiated at centromeres, and centromeric regions are the last to pair in the zygotene-pachytene transition. In late prophase, we first identified the proteins that reside at paired centromeres. We found that components of the central and lateral element and transverse filaments of the synaptonemal complex are retained at paired centromeres after disassembly of the synaptonemal complex along diplotene chromosome arms. The absence of SYCP1 prevents centromere pairing in knockout mouse spermatocytes. The localization dynamics of SYCP1 and SYCP3 suggest that they play different roles in promoting homologous centromere pairing. SYCP1 remains only at paired centromeres coincident with the time at which some kinetochore proteins begin loading at centromeres, consistent with a role in assembly of meiosis-specific kinetochores. After removal of SYCP1 from centromeres, SYCP3 then accumulates at paired centromeres where it may promote bi-orientation of homologous centromeres. We propose that, in addition to their roles as synaptonemal complex components, SYCP1 and SYCP3 act at the centromeres to promote the establishment and/or maintenance of centromere pairing and, by doing so, improve the segregation fidelity of mammalian meiotic chromosomes. PMID:22761579

Risk analysis of maintenance ship collisions with offshore wind turbines

NASA Astrophysics Data System (ADS)

Presencia, Carla E.; Shafiee, Mahmood

2018-07-01

A large number of offshore wind farms are planned to be built in remote deep-sea areas over the next five years. Though offshore wind sites are often located away from commercial ship traffic, the increased demand for repair or replacement services leads to high traffic densities of "maintenance ships". To date, the risk analysis of collision between maintenance ship vessels and offshore wind turbines has received very little attention. In this paper, we propose a methodology to evaluate and prioritise the collision risks associated with various kinds of ships used for carrying out maintenance tasks on different subassemblies of wind turbines in an offshore wind farm. It is also studied how the risks of ship collision with wind turbines are distributed between two main types of maintenance tasks, namely corrective and preventative. The proposed model is tested on an offshore wind turbine with seventeen components requiring five kinds of ships to perform the maintenance tasks. Our results indicate that collision risks are mostly associated with maintenance of few components of the wind turbine and in particular, those undergoing a corrective maintenance (replacement). Finally, several mitigation strategies are introduced to minimise the risk of maintenance ship collisions with offshore wind turbines.

78 FR 77574 - Protection System Maintenance Reliability Standard

Federal Register 2010, 2011, 2012, 2013, 2014

2013-12-24

... protection system component type, except that the maintenance program for all batteries associated with the... Electric System reliability and promoting efficiency through consolidation [of protection system-related... ITC that PRC-005-2 promotes efficiency by consolidating protection system maintenance requirements...

Fault Diagnosis approach based on a model-based reasoner and a functional designer for a wind turbine. An approach towards self-maintenance

NASA Astrophysics Data System (ADS)

Echavarria, E.; Tomiyama, T.; van Bussel, G. J. W.

2007-07-01

The objective of this on-going research is to develop a design methodology to increase the availability for offshore wind farms, by means of an intelligent maintenance system capable of responding to faults by reconfiguring the system or subsystems, without increasing service visits, complexity, or costs. The idea is to make use of the existing functional redundancies within the system and sub-systems to keep the wind turbine operational, even at a reduced capacity if necessary. Re-configuration is intended to be a built-in capability to be used as a repair strategy, based on these existing functionalities provided by the components. The possible solutions can range from using information from adjacent wind turbines, such as wind speed and direction, to setting up different operational modes, for instance re-wiring, re-connecting, changing parameters or control strategy. The methodology described in this paper is based on qualitative physics and consists of a fault diagnosis system based on a model-based reasoner (MBR), and on a functional redundancy designer (FRD). Both design tools make use of a function-behaviour-state (FBS) model. A design methodology based on the re-configuration concept to achieve self-maintained wind turbines is an interesting and promising approach to reduce stoppage rate, failure events, maintenance visits, and to maintain energy output possibly at reduced rate until the next scheduled maintenance.

49 CFR Appendix E to Part 238 - General Principles of Reliability-Based Maintenance Programs

Code of Federal Regulations, 2011 CFR

2011-10-01

... that have already occurred but were not evident to the operating crew. (b) Components or systems in a... shows decreasing reliability with increasing operating age. An age/time limit may be used to reduce the... maintenance of a component or system to protect the safety and operating capability of the equipment, a number...

49 CFR Appendix E to Part 238 - General Principles of Reliability-Based Maintenance Programs

Code of Federal Regulations, 2013 CFR

2013-10-01

... that have already occurred but were not evident to the operating crew. (b) Components or systems in a... shows decreasing reliability with increasing operating age. An age/time limit may be used to reduce the... maintenance of a component or system to protect the safety and operating capability of the equipment, a number...

49 CFR Appendix E to Part 238 - General Principles of Reliability-Based Maintenance Programs

Code of Federal Regulations, 2012 CFR

2012-10-01

... that have already occurred but were not evident to the operating crew. (b) Components or systems in a... shows decreasing reliability with increasing operating age. An age/time limit may be used to reduce the... maintenance of a component or system to protect the safety and operating capability of the equipment, a number...

49 CFR Appendix E to Part 238 - General Principles of Reliability-Based Maintenance Programs

Code of Federal Regulations, 2014 CFR

2014-10-01

... that have already occurred but were not evident to the operating crew. (b) Components or systems in a... shows decreasing reliability with increasing operating age. An age/time limit may be used to reduce the... maintenance of a component or system to protect the safety and operating capability of the equipment, a number...

Software Engineering Laboratory (SEL) Data Base Maintenance System (DBAM) user's guide and system description

NASA Technical Reports Server (NTRS)

Lo, P. S.; Card, D.

1983-01-01

The Software Engineering Laboratory (SEL) Data Base Maintenance System (DBAM) is explained. The various software facilities of the SEL, DBAM operating procedures, and DBAM system information are described. The relationships among DBAM components (baseline diagrams), component descriptions, overlay descriptions, indirect command file listings, file definitions, and sample data collection forms are provided.

Carrier Based Air Logistics Study: Maintenance Analysis.

DTIC Science & Technology

1982-01-01

MONITORING AGENCY NAME & ADDRESS(If dIierent loan Controling 01116.) 1S. SECURITY CLASS. (of Od. report) gel Unclassified IS&. DECL ASSI IlCATION/ OOWNGRAOIN...Management System AECL Avionics Equipment Configuration List AIMD Aircraft Intermediate Maintenance Department ASO Aviation Supply Office ASW...implementation. Component-specific data, and indentured[2] relationships between components extracted from the Aviation Supply Office ( ASO ) weapon

Determining optimal preventive maintenance interval for component of Well Barrier Element in an Oil & Gas Company

NASA Astrophysics Data System (ADS)

Siswanto, A.; Kurniati, N.

2018-04-01

An oil and gas company has 2,268 oil and gas wells. Well Barrier Element (WBE) is installed in a well to protect human, prevent asset damage and minimize harm to the environment. The primary WBE component is Surface Controlled Subsurface Safety Valve (SCSSV). The secondary WBE component is Christmas Tree Valves that consist of four valves i.e. Lower Master Valve (LMV), Upper Master Valve (UMV), Swab Valve (SV) and Wing Valve (WV). Current practice on WBE Preventive Maintenance (PM) program is conducted by considering the suggested schedule as stated on manual. Corrective Maintenance (CM) program is conducted when the component fails unexpectedly. Both PM and CM need cost and may cause production loss. This paper attempts to analyze the failure data and reliability based on historical data. Optimal PM interval is determined in order to minimize the total cost of maintenance per unit time. The optimal PM interval for SCSSV is 730 days, LMV is 985 days, UMV is 910 days, SV is 900 days and WV is 780 days. In average of all components, the cost reduction by implementing the suggested interval is 52%, while the reliability is improved by 4% and the availability is increased by 5%.

Managing aging in nuclear power plants: Insights from NRC maintenance team inspection reports

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

Fresco, A.; Subudhi, M.; Gunther, W.

1993-12-01

A plant`s maintenance program is the principal vehicle through which age-related degradation is managed. From 1988 to 1991, the NRC evaluated the maintenance program of every nuclear power plant in the United States. Forty-four out of a total of 67 of the reports issued on these in-depth team inspections were reviewed for insights into the strengths and weaknesses of the programs as related to the need to understand and manage the effects of aging on nuclear plant systems, structures, and components. Relevant information was extracted from these inspection reports and sorted into several categories, including Specific Aging Insights, Preventive Maintenance,more » Predictive Maintenance and Condition Monitoring, Post Maintenance Testing, Failure Trending, Root Cause Analysis and Usage of Probabilistic Risk Assessment in the Maintenance Process. Specific examples of inspection and monitoring techniques successfully used by utilities to detect degradation due to aging have been identified. The information also was sorted according to systems and components, including: Auxiliary Feedwater, Main Feedwater, High Pressure Injection for both BWRs and PWRs, Service Water, Instrument Air, and Emergency Diesel Generator Air Start Systems, and Emergency Diesel Generators Air Start Systems, emergency diesel generators, electrical components such as switchgear, breakers, relays, and motor control centers, motor operated valves and check valves. This information was compared to insights gained from the Nuclear Plant Aging Research (NPAR) Program. Attributes of plant maintenance programs where the NRC inspectors felt that improvement was needed to properly address the aging issue also are discussed.« less

Merkel cell polyomavirus recruits MYCL to the EP400 complex to promote oncogenesis.

PubMed

Cheng, Jingwei; Park, Donglim Esther; Berrios, Christian; White, Elizabeth A; Arora, Reety; Yoon, Rosa; Branigan, Timothy; Xiao, Tengfei; Westerling, Thomas; Federation, Alexander; Zeid, Rhamy; Strober, Benjamin; Swanson, Selene K; Florens, Laurence; Bradner, James E; Brown, Myles; Howley, Peter M; Padi, Megha; Washburn, Michael P; DeCaprio, James A

2017-10-01

Merkel cell carcinoma (MCC) frequently contains integrated copies of Merkel cell polyomavirus DNA that express a truncated form of Large T antigen (LT) and an intact Small T antigen (ST). While LT binds RB and inactivates its tumor suppressor function, it is less clear how ST contributes to MCC tumorigenesis. Here we show that ST binds specifically to the MYC homolog MYCL (L-MYC) and recruits it to the 15-component EP400 histone acetyltransferase and chromatin remodeling complex. We performed a large-scale immunoprecipitation for ST and identified co-precipitating proteins by mass spectrometry. In addition to protein phosphatase 2A (PP2A) subunits, we identified MYCL and its heterodimeric partner MAX plus the EP400 complex. Immunoprecipitation for MAX and EP400 complex components confirmed their association with ST. We determined that the ST-MYCL-EP400 complex binds together to specific gene promoters and activates their expression by integrating chromatin immunoprecipitation with sequencing (ChIP-seq) and RNA-seq. MYCL and EP400 were required for maintenance of cell viability and cooperated with ST to promote gene expression in MCC cell lines. A genome-wide CRISPR-Cas9 screen confirmed the requirement for MYCL and EP400 in MCPyV-positive MCC cell lines. We demonstrate that ST can activate gene expression in a EP400 and MYCL dependent manner and this activity contributes to cellular transformation and generation of induced pluripotent stem cells.

Aviation Maintenance Technology. General. G102 Fundamentals of Aircraft Maintenance. Instructor Material.

ERIC Educational Resources Information Center

Oklahoma State Board of Vocational and Technical Education, Stillwater. Curriculum and Instructional Materials Center.

These instructor materials for an aviation maintenance technology course contain four instructional modules. The modules cover the following topics: identifying basic components of aircraft, performing aircraft cleaning and corrosion control, interpreting blueprints and drawing sketches, identifying structural materials, and performing basic…

Exercise to Enhance Smoking Cessation: the Getting Physical on Cigarette Randomized Control Trial.

PubMed

Prapavessis, Harry; De Jesus, Stefanie; Fitzgeorge, Lindsay; Faulkner, Guy; Maddison, Ralph; Batten, Sandra

2016-06-01

Exercise has been proposed as a useful smoking cessation aid. The purpose of the present study is to determine the effect of an exercise-aided smoking cessation intervention program, with built-in maintenance components, on post-intervention 14-, 26- and 56-week cessation rates. Female cigarette smokers (n = 413) participating in a supervised exercise and nicotine replacement therapy (NRT) smoking cessation program were randomized to one of four conditions: exercise + smoking cessation maintenance, exercise maintenance + contact control, smoking cessation maintenance + contact control or contact control. The primary outcome was continuous smoking abstinence. Abstinence differences were found between the exercise and equal contact non-exercise maintenance groups at weeks 14 (57 vs 43 %), 26 (27 vs 21 %) and 56 (26 vs 23.5 %), respectively. Only the week 14 difference approached significance, p = 0.08. An exercise-aided NRT smoking cessation program with built-in maintenance components enhances post-intervention cessation rates at week 14 but not at weeks 26 and 56.

Detection of structural deterioration and associated airline maintenance problems

NASA Technical Reports Server (NTRS)

Henniker, H. D.; Mitchell, R. G.

1972-01-01

Airline operations involving the detection of structural deterioration and associated maintenance problems are discussed. The standard approach to the maintenance and inspection of aircraft components and systems is described. The frequency of inspections and the application of preventive maintenance practices are examined. The types of failure which airline transport aircraft encounter and the steps taken to prevent catastrophic failure are reported.

Improving hydraulic excavator performance through in line hydraulic oil contamination monitoring

NASA Astrophysics Data System (ADS)

Ng, Felix; Harding, Jennifer A.; Glass, Jacqueline

2017-01-01

It is common for original equipment manufacturers (OEMs) of high value products to provide maintenance or service packages to customers to ensure their products are maintained at peak efficiency throughout their life. To quickly and efficiently plan for maintenance requirements, OEMs require accurate information about the use and wear of their products. In recent decades, the aerospace industry in particular has become expert in using real time data for the purpose of product monitoring and maintenance scheduling. Significant quantities of real time usage data from product monitoring are commonly generated and transmitted back to the OEMs, where diagnostic and prognostic analysis will be carried out. More recently, other industries such as construction and automotive, are also starting to develop capabilities in these areas and condition based maintenance (CBM) is increasing in popularity as a means of satisfying customers' demands. CBM requires constant monitoring of real time product data by the OEMs, however the biggest challenge for these industries, in particular construction, is the lack of accurate and real time understanding of how their products are being used possibly because of the complex supply chains which exist in construction projects. This research focuses on current dynamic data acquisition techniques for mobile hydraulic systems, in this case the use of a mobile inline particle contamination sensor; the aim was to assess suitability to achieve both diagnostic and prognostic requirements of Condition Based Maintenance. It concludes that hydraulic oil contamination analysis, namely detection of metallic particulates, offers a reliable way to measure real time wear of hydraulic components.

Laboratory models for central nervous system tumor stem cell research.

PubMed

Khan, Imad Saeed; Ehtesham, Moneeb

2015-01-01

Central nervous system (CNS) tumors are complex organ systems comprising of a neoplastic component with associated vasculature, inflammatory cells, and reactive cellular and extracellular components. Research has identified a subset of cells in CNS tumors that portray defining properties of neural stem cells, namely, that of self-renewal and multi-potency. Growing evidence suggests that these tumor stem cells (TSC) play an important role in the maintenance and growth of the tumor. Furthermore, these cells have also been shown to be refractory to conventional therapy and may be crucial for tumor recurrence and metastasis. Current investigations are focusing on isolating these TSC from CNS tumors to investigate their unique biological processes. This understanding will help identify and develop more effective and comprehensive treatment strategies. This chapter provides an overview of some of the most commonly used laboratory models for CNSTSC research.

Highway Maintenance Equipment Operator. Miscellaneous Equipment. Training Materials.

ERIC Educational Resources Information Center

Perky, Sandra Dutreau; And Others

This curriculum guide provides instructional materials to assist in training equipment operators in the safe and effective use of highway maintenance equipment. It includes six units of instruction covering the small, specialized equipment used in maintenance operations. Each unit of instruction consists of eight basic components: performance…

Instruction manual model 600F, data transmission test set

NASA Technical Reports Server (NTRS)

1972-01-01

Information necessary for the operation and maintenance of the Model 600F Data Transmission Test Set is presented. A description is contained of the physical and functional characteristics; pertinent installation data; instructions for operating the equipment; general and detailed principles of operation; preventive and corrective maintenance procedures; and block, logic, and component layout diagrams of the equipment and its major component assemblies.

Implementation of a Computerized Maintenance Management System

NASA Technical Reports Server (NTRS)

Shen, Yong-Hong; Askari, Bruce

1994-01-01

A primer Computerized Maintenance Management System (CMMS) has been established for NASA Ames pressure component certification program. The CMMS takes full advantage of the latest computer technology and SQL relational database to perform periodic services for vital pressure components. The Ames certification program is briefly described and the aspects of the CMMS implementation are discussed as they are related to the certification objectives.

Initial flight qualification and operational maintenance of X-29A flight software

NASA Technical Reports Server (NTRS)

Earls, Michael R.; Sitz, Joel R.

1989-01-01

A discussion is presented of some significant aspects of the initial flight qualification and operational maintenance of the flight control system softward for the X-29A technology demonstrator. Flight qualification and maintenance of complex, embedded flight control system software poses unique problems. The X-29A technology demonstrator aircraft has a digital flight control system which incorporates functions generally considered too complex for analog systems. Organizational responsibilities, software assurance issues, tools, and facilities are discussed.

Implementing a Reliability Centered Maintenance Program at NASA's Kennedy Space Center

NASA Technical Reports Server (NTRS)

Tuttle, Raymond E.; Pete, Robert R.

1998-01-01

Maintenance practices have long focused on time based "preventive maintenance" techniques. Components were changed out and parts replaced based on how long they had been in place instead of what condition they were in. A reliability centered maintenance (RCM) program seeks to offer equal or greater reliability at decreased cost by insuring only applicable, effective maintenance is performed and by in large part replacing time based maintenance with condition based maintenance. A significant portion of this program involved introducing non-intrusive technologies, such as vibration analysis, oil analysis and I/R cameras, to an existing labor force and management team.

Minichromosome maintenance complex component 8 mutations cause primary ovarian insufficiency.

PubMed

Dou, Xiaoyun; Guo, Ting; Li, Guangyu; Zhou, LiGuang; Qin, Yingying; Chen, Zi-Jiang

2016-11-01

To investigate whether mutations in the minichromosome maintenance complex component 8 (MCM8) gene were present in 192 patients with sporadic primary ovarian insufficiency (POI). Retrospective case-control cohort study. University-based reproductive medicine center. A total of 192 patients with sporadic POI and 312 control women with regular menstruation (192 age-matched women and 120 women >45 years old). Sanger sequencing was performed in patients with sporadic POI, and potentially pathogenic variants were confirmed in matched controls. DNA damage was induced by mitomycinC (MMC) treatment, and DNA repair capacity was evaluated by histone H2AX phosphorylation level. Sanger sequencing for MCM8 was performed in 192 patients with sporadic POI, and functional experiments were performed to explore the deleterious effects of mutations identified. Two novel missense variants in MCM8, c. A950T (p. H317L), and c. A1802G (p. H601R), were identified in two patients with POI but absent in 312 controls (the upper 90% confidence limit for the proportion 2/192 is 2.24%). The HeLa cells overexpressing mutant p. H317L and p. H601R showed higher sensitivity to MMC compared with wild type. Furthermore, mutant p. H317L showed decreased repair capacity after MMC treatment with much more histone H2AX phosphorylation remaining after 2 hours of recovery. Our result suggests novel mutations p. H317L and p. H601R in the MCM8 gene are potentially causative for POI by dysfunctional DNA repair. Copyright © 2016 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

An Assessment of Integrated Health Management (IHM) Frameworks

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

N. Lybeck; M. Tawfik; L. Bond

In order to meet the ever increasing demand for energy, the United States nuclear industry is turning to life extension of existing nuclear power plants (NPPs). Economically ensuring the safe, secure, and reliable operation of aging nuclear power plants presents many challenges. The 2009 Light Water Reactor Sustainability Workshop identified online monitoring of active and structural components as essential to the better understanding and management of the challenges posed by aging nuclear power plants. Additionally, there is increasing adoption of condition-based maintenance (CBM) for active components in NPPs. These techniques provide a foundation upon which a variety of advanced onlinemore » surveillance, diagnostic, and prognostic techniques can be deployed to continuously monitor and assess the health of NPP systems and components. The next step in the development of advanced online monitoring is to move beyond CBM to estimating the remaining useful life of active components using prognostic tools. Deployment of prognostic health management (PHM) on the scale of a NPP requires the use of an integrated health management (IHM) framework - a software product (or suite of products) used to manage the necessary elements needed for a complete implementation of online monitoring and prognostics. This paper provides a thoughtful look at the desirable functions and features of IHM architectures. A full PHM system involves several modules, including data acquisition, system modeling, fault detection, fault diagnostics, system prognostics, and advisory generation (operations and maintenance planning). The standards applicable to PHM applications are indentified and summarized. A list of evaluation criteria for PHM software products, developed to ensure scalability of the toolset to an environment with the complexity of a NPP, is presented. Fourteen commercially available PHM software products are identified and classified into four groups: research tools, PHM system development tools, deployable architectures, and peripheral tools.« less

Telomere Capping Proteins are Structurally Related to RPA with an additional Telomere-Specific Domain

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

Gelinas, A.; Paschini, M; Reyes, F

Telomeres must be capped to preserve chromosomal stability. The conserved Stn1 and Ten1 proteins are required for proper capping of the telomere, although the mechanistic details of how they contribute to telomere maintenance are unclear. Here, we report the crystal structures of the C-terminal domain of the Saccharomyces cerevisiae Stn1 and the Schizosaccharomyces pombe Ten1 proteins. These structures reveal striking similarities to corresponding subunits in the replication protein A complex, further supporting an evolutionary link between telomere maintenance proteins and DNA repair complexes. Our structural and in vivo data of Stn1 identify a new domain that has evolved to supportmore » a telomere-specific role in chromosome maintenance. These findings endorse a model of an evolutionarily conserved mechanism of DNA maintenance that has developed as a result of increased chromosomal structural complexity.« less

Roles of the checkpoint sensor clamp Rad9-Rad1-Hus1 (911)-complex and the clamp loaders Rad17-RFC and Ctf18-RFC in Schizosaccharomyces pombe telomere maintenance.

PubMed

Khair, Lyne; Chang, Ya-Ting; Subramanian, Lakxmi; Russell, Paul; Nakamura, Toru M

2010-06-01

While telomeres must provide mechanisms to prevent DNA repair and DNA damage checkpoint factors from fusing chromosome ends and causing permanent cell cycle arrest, these factors associate with functional telomeres and play critical roles in the maintenance of telomeres. Previous studies have established that Tel1 (ATM) and Rad3 (ATR) kinases play redundant but essential roles for telomere maintenance in fission yeast. In addition, the Rad9-Rad1-Hus1 (911) and Rad17-RFC complexes work downstream of Rad3 (ATR) in fission yeast telomere maintenance. Here, we investigated how 911, Rad17-RFC and another RFC-like complex Ctf18-RFC contribute to telomere maintenance in fission yeast cells lacking Tel1 and carrying a novel hypomorphic allele of rad3 (DBD-rad3), generated by the fusion between the DNA binding domain (DBD) of the fission yeast telomere capping protein Pot1 and Rad3. Our investigations have uncovered a surprising redundancy for Rad9 and Hus1 in allowing Rad1 to contribute to telomere maintenance in DBD-rad3 tel1 cells. In addition, we found that Rad17-RFC and Ctf18-RFC carry out redundant telomere maintenance functions in DBD-rad3 tel1 cells. Since checkpoint sensor proteins are highly conserved, genetic redundancies uncovered here may be relevant to telomere maintenance and detection of DNA damage in other eukaryotes.

Roles of the Checkpoint Sensor Clamp Rad9-Rad1-Hus1 (911)-Complex and the Clamp Loaders Rad17-RFC and Ctf18-RFC in Schizosaccharomyces pombe Telomere Maintenance

PubMed Central

Khair, Lyne; Chang, Ya-Ting; Subramanian, Lakxmi; Russell, Paul; Nakamura, Toru M.

2011-01-01

While telomeres must provide mechanisms to prevent DNA repair and DNA damage checkpoint factors from fusing chromosome ends and causing permanent cell cycle arrest, these factors associate with functional telomeres and play critical roles in the maintenance of telomeres. Previous studies have established that Tel1 (ATM) and Rad3 (ATR) kinases play redundant but essential roles for telomere maintenance in fission yeast. In addition, the Rad9-Rad1-Hus1 (911) and Rad17-RFC complexes work downstream of Rad3 (ATR) in fission yeast telomere maintenance. Here, we investigated how 911, Rad17-RFC and another RFC-like complex Ctf18-RFC contribute to telomere maintenance in fission yeast cells lacking Tel1 and carrying a novel hypomorphic allele of rad3 (DBD-rad3), generated by the fusion between the DNA binding domain (DBD) of the fission yeast telomere capping protein Pot1 and Rad3. Our investigations have uncovered a surprising redundancy for Rad9 and Hus1 in allowing Rad1 to contribute to telomere maintenance in DBD-rad3 tel1Δ cells. In addition, we found that Rad17-RFC and Ctf18-RFC carry out redundant telomere maintenance functions in DBD-rad3 tel1Δ cells. Since checkpoint sensor proteins are highly conserved, genetic redundancies uncovered here may be relevant to telomere maintenance and detection of DNA damage in other eukaryotes. PMID:20505337

Telomere-driven diseases and telomere-targeting therapies

PubMed Central

2017-01-01

Telomeres, the protective ends of linear chromosomes, shorten throughout an individual’s lifetime. Telomere shortening is proposed to be a primary molecular cause of aging. Short telomeres block the proliferative capacity of stem cells, affecting their potential to regenerate tissues, and trigger the development of age-associated diseases. Mutations in telomere maintenance genes are associated with pathologies referred to as telomere syndromes, including Hoyeraal-Hreidarsson syndrome, dyskeratosis congenita, pulmonary fibrosis, aplastic anemia, and liver fibrosis. Telomere shortening induces chromosomal instability that, in the absence of functional tumor suppressor genes, can contribute to tumorigenesis. In addition, mutations in telomere length maintenance genes and in shelterin components, the protein complex that protects telomeres, have been found to be associated with different types of cancer. These observations have encouraged the development of therapeutic strategies to treat and prevent telomere-associated diseases, namely aging-related diseases, including cancer. Here we review the molecular mechanisms underlying telomere-driven diseases and highlight recent advances in the preclinical development of telomere-targeted therapies using mouse models. PMID:28254828

Interactions between parasites and microbial communities in the human gut.

PubMed

Berrilli, Federica; Di Cave, David; Cavallero, Serena; D'Amelio, Stefano

2012-01-01

The interactions between intestinal microbiota, immune system, and pathogens describe the human gut as a complex ecosystem, where all components play a relevant role in modulating each other and in the maintenance of homeostasis. The balance among the gut microbiota and the human body appear to be crucial for health maintenance. Intestinal parasites, both protozoans and helminths, interact with the microbial community modifying the balance between host and commensal microbiota. On the other hand, gut microbiota represents a relevant factor that may strongly interfere with the pathophysiology of the infections. In addition to the function that gut commensal microbiota may have in the processes that determine the survival and the outcome of many parasitic infections, including the production of nutritive macromolecules, also probiotics can play an important role in reducing the pathogenicity of many parasites. On these bases, there is a growing interest in explaining the rationale on the possible interactions between the microbiota, immune response, inflammatory processes, and intestinal parasites.

Interactions between parasites and microbial communities in the human gut

PubMed Central

Berrilli, Federica; Di Cave, David; Cavallero, Serena; D'Amelio, Stefano

2012-01-01

The interactions between intestinal microbiota, immune system, and pathogens describe the human gut as a complex ecosystem, where all components play a relevant role in modulating each other and in the maintenance of homeostasis. The balance among the gut microbiota and the human body appear to be crucial for health maintenance. Intestinal parasites, both protozoans and helminths, interact with the microbial community modifying the balance between host and commensal microbiota. On the other hand, gut microbiota represents a relevant factor that may strongly interfere with the pathophysiology of the infections. In addition to the function that gut commensal microbiota may have in the processes that determine the survival and the outcome of many parasitic infections, including the production of nutritive macromolecules, also probiotics can play an important role in reducing the pathogenicity of many parasites. On these bases, there is a growing interest in explaining the rationale on the possible interactions between the microbiota, immune response, inflammatory processes, and intestinal parasites. PMID:23162802

Highway Maintenance Equipment Operator. Specialized Equipment. Training Materials.

ERIC Educational Resources Information Center

Perky, Sandra Dutreau; And Others

This curriculum guide provides instructional materials to assist in training equipment operators in the safe and effective use of highway maintenance equipment. It includes 18 units of instruction covering the large equipment used in maintenance operations. Each unit of instruction consists of eight basic components: performance objectives,…

AUTOMOTIVE DIESEL MAINTENANCE 1. UNIT IX, ENGINE COMPONENTS.

ERIC Educational Resources Information Center

Human Engineering Inst., Cleveland, OH.

THIS MODULE OF A 30-MODULE COURSE IS DESIGNED TO DEVELOP AN UNDERSTANDING OF THE CONSTRUCTION, FUNCTION, AND MAINTENANCE OF DIESEL ENGINE CRANKSHAFTS, CAMSHAFTS, AND ASSOCIATED BEARINGS. TOPICS ARE SHAFTS AND BEARINGS, CAMSHAFTS, BEARINGS AND THEIR MAINTENANCE, AND DETECTING FAILURE. THE MODULE CONSISTS OF A SELF-INSTRUCTIONAL BRANCH PROGRAMED…

Installation, maintenance and operating manual for the Lucas-type fuel injection system of the 3 B rotary engine

NASA Technical Reports Server (NTRS)

1985-01-01

The installation procedure, maintenance, adjustment and operation of a Lucas type fuel injection system for 13B rotary racing engine is outlined. Components of the fuel injection system and installation procedure and notes are described. Maintenance, adjustment, and operation are discussed.

Human area MT+ shows load-dependent activation during working memory maintenance with continuously morphing stimulation.

PubMed

Galashan, Daniela; Fehr, Thorsten; Kreiter, Andreas K; Herrmann, Manfred

2014-07-11

Initially, human area MT+ was considered a visual area solely processing motion information but further research has shown that it is also involved in various different cognitive operations, such as working memory tasks requiring motion-related information to be maintained or cognitive tasks with implied or expected motion.In the present fMRI study in humans, we focused on MT+ modulation during working memory maintenance using a dynamic shape-tracking working memory task with no motion-related working memory content. Working memory load was systematically varied using complex and simple stimulus material and parametrically increasing retention periods. Activation patterns for the difference between retention of complex and simple memorized stimuli were examined in order to preclude that the reported effects are caused by differences in retrieval. Conjunction analysis over all delay durations for the maintenance of complex versus simple stimuli demonstrated a wide-spread activation pattern. Percent signal change (PSC) in area MT+ revealed a pattern with higher values for the maintenance of complex shapes compared to the retention of a simple circle and with higher values for increasing delay durations. The present data extend previous knowledge by demonstrating that visual area MT+ presents a brain activity pattern usually found in brain regions that are actively involved in working memory maintenance.

Sensitivity Study for Long Term Reliability

NASA Technical Reports Server (NTRS)

White, Allan L.

2008-01-01

This paper illustrates using Markov models to establish system and maintenance requirements for small electronic controllers where the goal is a high probability of continuous service for a long period of time. The system and maintenance items considered are quality of components, various degrees of simple redundancy, redundancy with reconfiguration, diagnostic levels, periodic maintenance, and preventive maintenance. Markov models permit a quantitative investigation with comparison and contrast. An element of special interest is the use of conditional probability to study the combination of imperfect diagnostics and periodic maintenance.

Alternative Fuels Data Center: Newsletters

Science.gov Websites

Offers information on the development and maintenance of electric motors, drives, and related components Fuels Fuel Prices Conserve Fuel Idle Reduction Parts & Equipment Maintenance Driving Behavior Fleet

The human CTC1/STN1/TEN1 complex regulates telomere maintenance in ALT cancer cells.

PubMed

Huang, Chenhui; Jia, Pingping; Chastain, Megan; Shiva, Olga; Chai, Weihang

2017-06-15

Maintaining functional telomeres is important for long-term proliferation of cells. About 15% of cancer cells are telomerase-negative and activate the alternative-lengthening of telomeres (ALT) pathway to maintain their telomeres. Recent studies have shown that the human CTC1/STN1/TEN1 complex (CST) plays a multi-faceted role in telomere maintenance in telomerase-expressing cancer cells. However, the role of CST in telomere maintenance in ALT cells is unclear. Here, we report that human CST forms a functional complex localizing in the ALT-associated PML bodies (APBs) in ALT cells throughout the cell cycle. Suppression of CST induces telomere instabilities including telomere fragility and elevates telomeric DNA recombination, leading to telomere dysfunction. In addition, CST deficiency significantly diminishes the abundance of extrachromosomal circular telomere DNA known as C-circles and t-circles. Suppression of CST also results in multinucleation in ALT cells and impairs cell proliferation. Our findings imply that the CST complex plays an important role in regulating telomere maintenance in ALT cells. Copyright © 2017 Elsevier Inc. All rights reserved.

Quantification of Forecasting and Change-Point Detection Methods for Predictive Maintenance

DTIC Science & Technology

2015-08-19

industries to manage the service life of equipment, and also to detect precursors to the failure of components found in nuclear power plants, wind turbines ...detection methods for predictive maintenance 5a. CONTRACT NUMBER FA2386-14-1-4096 5b. GRANT NUMBER Grant 14IOA015 AOARD-144096 5c. PROGRAM ELEMENT...sensitive to changes related to abnormality. 15. SUBJECT TERMS predictive maintenance , predictive maintenance , forecasting 16

Cognitive control components and speech symptoms in people with schizophrenia.

PubMed

Becker, Theresa M; Cicero, David C; Cowan, Nelson; Kerns, John G

2012-03-30

Previous schizophrenia research suggests poor cognitive control is associated with schizophrenia speech symptoms. However, cognitive control is a broad construct. Two important cognitive control components are poor goal maintenance and poor verbal working memory storage. In the current research, people with schizophrenia (n=45) performed three cognitive tasks that varied in their goal maintenance and verbal working memory storage demands. Speech symptoms were assessed using clinical rating scales, ratings of disorganized speech from typed transcripts, and self-reported disorganization. Overall, alogia was associated with both goal maintenance and verbal working memory tasks. Objectively rated disorganized speech was associated with poor goal maintenance and with a task that included both goal maintenance and verbal working memory storage demands. In contrast, self-reported disorganization was unrelated to either amount of objectively rated disorganized speech or to cognitive control task performance, instead being associated with negative mood symptoms. Overall, our results suggest that alogia is associated with both poor goal maintenance and poor verbal working memory storage and that disorganized speech is associated with poor goal maintenance. In addition, patients' own assessment of their disorganization is related to negative mood, but perhaps not to objective disorganized speech or to cognitive control task performance. Published by Elsevier Ireland Ltd.

Leadership Maintenance: Filling the Gap for Leadership Competences

ERIC Educational Resources Information Center

Rajbhandari, Mani Man Singh; Rajbhandari, Smriti

2015-01-01

In this study, leadership maintenance employs psychological, sociological and physiological paradigms in creating a conducive environment for both leaders' and followers' well-being in educational settings. Leadership maintenance is an ongoing process, which entails the understanding of leader's cognitive complexity, relational approaches towards…

14 CFR Appendix A to Part 33 - Instructions for Continued Airworthiness

Code of Federal Regulations, 2013 CFR

2013-01-01

... degree of complexity requiring specialized maintenance techniques, test equipment, or expertise. The... Limitations section must also prescribe the mandatory post-flight inspections and maintenance actions... adequacy of the instructions for mandatory post-flight inspections and maintenance actions prescribed under...

14 CFR Appendix A to Part 33 - Instructions for Continued Airworthiness

Code of Federal Regulations, 2014 CFR

2014-01-01

... degree of complexity requiring specialized maintenance techniques, test equipment, or expertise. The... Limitations section must also prescribe the mandatory post-flight inspections and maintenance actions... adequacy of the instructions for mandatory post-flight inspections and maintenance actions prescribed under...

14 CFR Appendix A to Part 33 - Instructions for Continued Airworthiness

Code of Federal Regulations, 2010 CFR

2010-01-01

... degree of complexity requiring specialized maintenance techniques, test equipment, or expertise. The... Limitations section must also prescribe the mandatory post-flight inspections and maintenance actions... adequacy of the instructions for mandatory post-flight inspections and maintenance actions prescribed under...

FAAP20: a novel ubiquitin-binding FA nuclear core-complex protein required for functional integrity of the FA-BRCA DNA repair pathway

PubMed Central

Ali, Abdullah Mahmood; Pradhan, Arun; Singh, Thiyam Ramsingh; Du, Changhu; Li, Jie; Wahengbam, Kebola; Grassman, Elke; Auerbach, Arleen D.; Pang, Qishen

2012-01-01

Fanconi anemia (FA) nuclear core complex is a multiprotein complex required for the functional integrity of the FA-BRCA pathway regulating DNA repair. This pathway is inactivated in FA, a devastating genetic disease, which leads to hematologic defects and cancer in patients. Here we report the isolation and characterization of a novel 20-kDa FANCA-associated protein (FAAP20). We show that FAAP20 is an integral component of the FA nuclear core complex. We identify a region on FANCA that physically interacts with FAAP20, and show that FANCA regulates stability of this protein. FAAP20 contains a conserved ubiquitin-binding zinc-finger domain (UBZ), and binds K-63–linked ubiquitin chains in vitro. The FAAP20-UBZ domain is not required for interaction with FANCA, but is required for DNA-damage–induced chromatin loading of FANCA and the functional integrity of the FA pathway. These findings reveal critical roles for FAAP20 in the FA-BRCA pathway of DNA damage repair and genome maintenance. PMID:22343915

Preventive Maintenance Study: A Key Component in Engineering Education to Enhance Industrial Productivity and Competitiveness.

ERIC Educational Resources Information Center

Nachlas, Joel A.; Cassady, C. Richard

1999-01-01

Suggests that a chief contributor to the continued economic success of the western economies will be the productivity gains available through efficient preventative maintenance planning and argues for appropriate changes in engineering curricula. Describes the formulation of maintenance planning problems and illustrates with numerical examples the…

AUTOMOTIVE DIESEL MAINTENANCE, UNIT V, MAINTAINING THE LUBRICATION SYSTEM--DETROIT DIESEL ENGINE.

ERIC Educational Resources Information Center

Human Engineering Inst., Cleveland, OH.

THIS MODULE OF A 30-MODULE COURSE IS DESIGNED TO DEVELOP AN UNDERSTANDING OF THE OPERATION AND MAINTENANCE OF THE DIESEL ENGINE LUBRICATION SYSTEM. TOPICS ARE LUBE OILS USED, MAINTENANCE OF THE LUBRICATION SYSTEM, AND CRANKCASE VENTILATION COMPONENTS. THE MODULE CONSISTS OF A SELF-INSTRUCTIONAL BRANCH PROGRAMED TRAINING FILM "BASIC ENGINE…

30 CFR 75.1731 - Maintenance of belt conveyors and belt conveyor entries.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Maintenance of belt conveyors and belt conveyor....1731 Maintenance of belt conveyors and belt conveyor entries. (a) Damaged rollers, or other damaged belt conveyor components, which pose a fire hazard must be immediately repaired or replaced. All other...

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

Coble, Jamie B.; Coles, Garill A.; Ramuhalli, Pradeep

Advanced small modular reactors (aSMRs) can provide the United States with a safe, sustainable, and carbon-neutral energy source. The controllable day-to-day costs of aSMRs are expected to be dominated by operation and maintenance costs. Health and condition assessment coupled with online risk monitors can potentially enhance affordability of aSMRs through optimized operational planning and maintenance scheduling. Currently deployed risk monitors are an extension of probabilistic risk assessment (PRA). For complex engineered systems like nuclear power plants, PRA systematically combines event likelihoods and the probability of failure (POF) of key components, so that when combined with the magnitude of possible adversemore » consequences to determine risk. Traditional PRA uses population-based POF information to estimate the average plant risk over time. Currently, most nuclear power plants have a PRA that reflects the as-operated, as-modified plant; this model is updated periodically, typically once a year. Risk monitors expand on living PRA by incorporating changes in the day-by-day plant operation and configuration (e.g., changes in equipment availability, operating regime, environmental conditions). However, population-based POF (or population- and time-based POF) is still used to populate fault trees. Health monitoring techniques can be used to establish condition indicators and monitoring capabilities that indicate the component-specific POF at a desired point in time (or over a desired period), which can then be incorporated in the risk monitor to provide a more accurate estimate of the plant risk in different configurations. This is particularly important for active systems, structures, and components (SSCs) proposed for use in aSMR designs. These SSCs may differ significantly from those used in the operating fleet of light-water reactors (or even in LWR-based SMR designs). Additionally, the operating characteristics of aSMRs can present significantly different requirements, including the need to operate in different coolant environments, higher operating temperatures, and longer operating cycles between planned refueling and maintenance outages. These features, along with the relative lack of operating experience for some of the proposed advanced designs, may limit the ability to estimate event probability and component POF with a high degree of certainty. Incorporating real-time estimates of component POF may compensate for a relative lack of established knowledge about the long-term component behavior and improve operational and maintenance planning and optimization. The particular eccentricities of advanced reactors and small modular reactors provide unique challenges and needs for advanced instrumentation, control, and human-machine interface (ICHMI) techniques such as enhanced risk monitors (ERM) in aSMRs. Several features of aSMR designs increase the need for accurate characterization of the real-time risk during operation and maintenance activities. A number of technical gaps in realizing ERM exist, and these gaps are largely independent of the specific reactor technology. As a result, the development of a framework for ERM would enable greater situational awareness regardless of the specific class of reactor technology. A set of research tasks are identified in a preliminary research plan to enable the development, testing, and demonstration of such a framework. Although some aspects of aSMRs, such as specific operational characteristics, will vary and are not now completely defined, the proposed framework is expected to be relevant regardless of such uncertainty. The development of an ERM framework will provide one of the key technical developments necessary to ensure the economic viability of aSMRs.« less

Training and generalization of laundry skills: a multiple probe evaluation with handicapped persons.

PubMed Central

Thompson, T J; Braam, S J; Fugua, R W

1982-01-01

An instructional procedure composed of a graded sequence of prompts and token reinforcement was used to train a complex chain of behaviors which included sorting, washing, and drying clothes. A multiple probe design with sequential instruction across seven major components of the laundering routine was used to demonstrate experimental control. Students were taught to launder clothing using machines located in their school and generalization was assessed later on machines located in the public laundromat. A comparison of students' laundry skills with those of normal peers indicated similar levels of proficiency. Follow-up probes demonstrated maintenance of laundry skills over a 10-month period. PMID:7096228

Training and generalization of laundry skills: a multiple probe evaluation with handicapped persons.

PubMed

Thompson, T J; Braam, S J; Fugua, R W

1982-01-01

An instructional procedure composed of a graded sequence of prompts and token reinforcement was used to train a complex chain of behaviors which included sorting, washing, and drying clothes. A multiple probe design with sequential instruction across seven major components of the laundering routine was used to demonstrate experimental control. Students were taught to launder clothing using machines located in their school and generalization was assessed later on machines located in the public laundromat. A comparison of students' laundry skills with those of normal peers indicated similar levels of proficiency. Follow-up probes demonstrated maintenance of laundry skills over a 10-month period.

Methodology of decreasing software complexity using ontology

NASA Astrophysics Data System (ADS)

DÄ browska-Kubik, Katarzyna

2015-09-01

In this paper a model of web application`s source code, based on the OSD ontology (Ontology for Software Development), is proposed. This model is applied to implementation and maintenance phase of software development process through the DevOntoCreator tool [5]. The aim of this solution is decreasing software complexity of that source code, using many different maintenance techniques, like creation of documentation, elimination dead code, cloned code or bugs, which were known before [1][2]. Due to this approach saving on software maintenance costs of web applications will be possible.

Review of Residential Comfort Control Products and Opportunities

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

Metzger, Cheryn E.; Goyal, Siddharth; Baechler, Michael C.

This paper begins by discussing the interaction of each major component in advanced sensor and control applications related to HVAC equipment. The paper also looks at the applications of these components to commissioning, maintenance and operations of the HVAC equipment in residential buildings. A summary of state-of-the-art product features is also provided. These products are categorized through their primary application type (commissioning/maintenance or operation) and the features are categorized by component type (sensors, data storage, human-in-the-loop, communication, and controls). A common theme that emerges from this study is the importance of the ability for various product categories to be connectedmore » to each other. There are many manufacturers of sensors and many manufacturers of controls, but the power to automate any commissioning, maintenance or operation application, requires connectivity.« less

A role for heterochromatin protein 1γ at human telomeres

PubMed Central

Canudas, Silvia; Houghtaling, Benjamin R.; Bhanot, Monica; Sasa, Ghadir; Savage, Sharon A.; Bertuch, Alison A.; Smith, Susan

2011-01-01

Human telomere function is mediated by shelterin, a six-subunit complex that is required for telomere replication, protection, and cohesion. TIN2, the central component of shelterin, has binding sites to three subunits: TRF1, TRF2, and TPP1. Here we identify a fourth partner, heterochromatin protein 1γ (HP1γ), that binds to a conserved canonical HP1-binding motif, PXVXL, in the C-terminal domain of TIN2. We show that HP1γ localizes to telomeres in S phase, where it is required to establish/maintain cohesion. We further demonstrate that the HP1-binding site in TIN2 is required for sister telomere cohesion and can impact telomere length maintenance by telomerase. Remarkably, the PTVML HP1-binding site is embedded in the recently identified cluster of mutations in TIN2 that gives rise to dyskeratosis congenita (DC), an inherited bone marrow failure syndrome caused by defects in telomere maintenance. We show that DC-associated mutations in TIN2 abrogate binding to HP1γ and that DC patient cells are defective in sister telomere cohesion. Our data indicate a novel requirement for HP1γ in the establishment/maintenance of cohesion at human telomeres and, furthermore, may provide insight into the mechanism of pathogenesis in TIN2-mediated DC. PMID:21865325

Reliability Centred Maintenance (RCM) Analysis of Laser Machine in Filling Lithos at PT X

NASA Astrophysics Data System (ADS)

Suryono, M. A. E.; Rosyidi, C. N.

2018-03-01

PT. X used automated machines which work for sixteen hours per day. Therefore, the machines should be maintained to keep the availability of the machines. The aim of this research is to determine maintenance tasks according to the cause of component’s failure using Reliability Centred Maintenance (RCM) and determine the amount of optimal inspection frequency which must be performed to the machine at filling lithos process. In this research, RCM is used as an analysis tool to determine the critical component and find optimal inspection frequencies to maximize machine’s reliability. From the analysis, we found that the critical machine in filling lithos process is laser machine in Line 2. Then we proceed to determine the cause of machine’s failure. Lastube component has the highest Risk Priority Number (RPN) among other components such as power supply, lens, chiller, laser siren, encoder, conveyor, and mirror galvo. Most of the components have operational consequences and the others have hidden failure consequences and safety consequences. Time-directed life-renewal task, failure finding task, and servicing task can be used to overcome these consequences. The results of data analysis show that the inspection must be performed once a month for laser machine in the form of preventive maintenance to lowering the downtime.

A Model of Compound Heterozygous, Loss-of-Function Alleles Is Broadly Consistent with Observations from Complex-Disease GWAS Datasets

PubMed Central

Sanjak, Jaleal S.; Long, Anthony D.; Thornton, Kevin R.

2017-01-01

The genetic component of complex disease risk in humans remains largely unexplained. A corollary is that the allelic spectrum of genetic variants contributing to complex disease risk is unknown. Theoretical models that relate population genetic processes to the maintenance of genetic variation for quantitative traits may suggest profitable avenues for future experimental design. Here we use forward simulation to model a genomic region evolving under a balance between recurrent deleterious mutation and Gaussian stabilizing selection. We consider multiple genetic and demographic models, and several different methods for identifying genomic regions harboring variants associated with complex disease risk. We demonstrate that the model of gene action, relating genotype to phenotype, has a qualitative effect on several relevant aspects of the population genetic architecture of a complex trait. In particular, the genetic model impacts genetic variance component partitioning across the allele frequency spectrum and the power of statistical tests. Models with partial recessivity closely match the minor allele frequency distribution of significant hits from empirical genome-wide association studies without requiring homozygous effect sizes to be small. We highlight a particular gene-based model of incomplete recessivity that is appealing from first principles. Under that model, deleterious mutations in a genomic region partially fail to complement one another. This model of gene-based recessivity predicts the empirically observed inconsistency between twin and SNP based estimated of dominance heritability. Furthermore, this model predicts considerable levels of unexplained variance associated with intralocus epistasis. Our results suggest a need for improved statistical tools for region based genetic association and heritability estimation. PMID:28103232

High-precision relative position and attitude measurement for on-orbit maintenance of spacecraft

NASA Astrophysics Data System (ADS)

Zhu, Bing; Chen, Feng; Li, Dongdong; Wang, Ying

2018-02-01

In order to realize long-term on-orbit running of satellites, space stations, etc spacecrafts, in addition to the long life design of devices, The life of the spacecraft can also be extended by the on-orbit servicing and maintenance. Therefore, it is necessary to keep precise and detailed maintenance of key components. In this paper, a high-precision relative position and attitude measurement method used in the maintenance of key components is given. This method mainly considers the design of the passive cooperative marker, light-emitting device and high resolution camera in the presence of spatial stray light and noise. By using a series of algorithms, such as background elimination, feature extraction, position and attitude calculation, and so on, the high precision relative pose parameters as the input to the control system between key operation parts and maintenance equipment are obtained. The simulation results show that the algorithm is accurate and effective, satisfying the requirements of the precision operation technique.

Dependency visualization for complex system understanding

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

Smart, J. Allison Cory

1994-09-01

With the volume of software in production use dramatically increasing, the importance of software maintenance has become strikingly apparent. Techniques now sought and developed for reverse engineering and design extraction and recovery. At present, numerous commercial products and research tools exist which are capable of visualizing a variety of programming languages and software constructs. The list of new tools and services continues to grow rapidly. Although the scope of the existing commercial and academic product set is quite broad, these tools still share a common underlying problem. The ability of each tool to visually organize object representations is increasingly impairedmore » as the number of components and component dependencies within systems increases. Regardless of how objects are defined, complex ``spaghetti`` networks result in nearly all large system cases. While this problem is immediately apparent in modem systems analysis involving large software implementations, it is not new. As will be discussed in Chapter 2, related problems involving the theory of graphs were identified long ago. This important theoretical foundation provides a useful vehicle for representing and analyzing complex system structures. While the utility of directed graph based concepts in software tool design has been demonstrated in literature, these tools still lack the capabilities necessary for large system comprehension. This foundation must therefore be expanded with new organizational and visualization constructs necessary to meet this challenge. This dissertation addresses this need by constructing a conceptual model and a set of methods for interactively exploring, organizing, and understanding the structure of complex software systems.« less

LTPP maintenance and rehabilitation data review

DOT National Transportation Integrated Search

2001-02-01

The maintenance and rehabilitation (M&R) activities of pavement structures become increasingly important as pavements deteriorate with time and traffic. Since its inception, the Long Term Pavement Performance (LTPP) component of the Strategic Highway...

SCAR Mediates Light-Induced Root Elongation in Arabidopsis through Photoreceptors and Proteasomes[W][OA

PubMed Central

Dyachok, Julia; Zhu, Ling; Liao, Fuqi; He, Ji; Huq, Enamul; Blancaflor, Elison B.

2011-01-01

The ARP2/3 complex, a highly conserved nucleator of F-actin, and its activator, the SCAR complex, are essential for growth in plants and animals. In this article, we present a pathway through which roots of Arabidopsis thaliana directly perceive light to promote their elongation. The ARP2/3-SCAR complex and the maintenance of longitudinally aligned F-actin arrays are crucial components of this pathway. The involvement of the ARP2/3-SCAR complex in light-regulated root growth is supported by our finding that mutants of the SCAR complex subunit BRK1/HSPC300, or other individual subunits of the ARP2/3-SCAR complex, showed a dramatic inhibition of root elongation in the light, which mirrored reduced growth of wild-type roots in the dark. SCAR1 degradation in dark-grown wild-type roots by constitutive photomorphogenic 1 (COP1) E3 ligase and 26S proteasome accompanied the loss of longitudinal F-actin and reduced root growth. Light perceived by the root photoreceptors, cryptochrome and phytochrome, suppressed COP1-mediated SCAR1 degradation. Taken together, our data provide a biochemical explanation for light-induced promotion of root elongation by the ARP2/3-SCAR complex. PMID:21972261

Fanconi anemia (FA) binding protein FAAP20 stabilizes FA complementation group A (FANCA) and participates in interstrand cross-link repair.

PubMed

Leung, Justin Wai Chung; Wang, Yucai; Fong, Ka Wing; Huen, Michael Shing Yan; Li, Lei; Chen, Junjie

2012-03-20

The Fanconi anemia (FA) pathway participates in interstrand cross-link (ICL) repair and the maintenance of genomic stability. The FA core complex consists of eight FA proteins and two Fanconi anemia-associated proteins (FAAP24 and FAAP100). The FA core complex has ubiquitin ligase activity responsible for monoubiquitination of the FANCI-FANCD2 (ID) complex, which in turn initiates a cascade of biochemical events that allow processing and removal of cross-linked DNA and thereby promotes cell survival following DNA damage. Here, we report the identification of a unique component of the FA core complex, namely, FAAP20, which contains a RAD18-like ubiquitin-binding zinc-finger domain. Our data suggest that FAAP20 promotes the functional integrity of the FA core complex via its direct interaction with the FA gene product, FANCA. Indeed, somatic knockout cells devoid of FAAP20 displayed the hallmarks of FA cells, including hypersensitivity to DNA cross-linking agents, chromosome aberrations, and reduced FANCD2 monoubiquitination. Taking these data together, our study indicates that FAAP20 is an important player involved in the FA pathway.

Fanconi anemia (FA) binding protein FAAP20 stabilizes FA complementation group A (FANCA) and participates in interstrand cross-link repair

PubMed Central

Leung, Justin Wai Chung; Wang, Yucai; Fong, Ka Wing; Huen, Michael Shing Yan; Li, Lei; Chen, Junjie

2012-01-01

The Fanconi anemia (FA) pathway participates in interstrand cross-link (ICL) repair and the maintenance of genomic stability. The FA core complex consists of eight FA proteins and two Fanconi anemia-associated proteins (FAAP24 and FAAP100). The FA core complex has ubiquitin ligase activity responsible for monoubiquitination of the FANCI-FANCD2 (ID) complex, which in turn initiates a cascade of biochemical events that allow processing and removal of cross-linked DNA and thereby promotes cell survival following DNA damage. Here, we report the identification of a unique component of the FA core complex, namely, FAAP20, which contains a RAD18-like ubiquitin-binding zinc-finger domain. Our data suggest that FAAP20 promotes the functional integrity of the FA core complex via its direct interaction with the FA gene product, FANCA. Indeed, somatic knockout cells devoid of FAAP20 displayed the hallmarks of FA cells, including hypersensitivity to DNA cross-linking agents, chromosome aberrations, and reduced FANCD2 monoubiquitination. Taking these data together, our study indicates that FAAP20 is an important player involved in the FA pathway. PMID:22396592

H3K9me3 demethylase Kdm4d facilitates the formation of pre-initiative complex and regulates DNA replication

PubMed Central

Wu, Rentian; Wang, Zhiquan; Zhang, Honglian; Gan, Haiyun; Zhang, Zhiguo

2017-01-01

DNA replication is tightly regulated to occur once and only once per cell cycle. How chromatin, the physiological substrate of DNA replication machinery, regulates DNA replication remains largely unknown. Here we show that histone H3 lysine 9 demethylase Kdm4d regulates DNA replication in eukaryotic cells. Depletion of Kdm4d results in defects in DNA replication, which can be rescued by the expression of H3K9M, a histone H3 mutant transgene that reverses the effect of Kdm4d on H3K9 methylation. Kdm4d interacts with replication proteins, and its recruitment to DNA replication origins depends on the two pre-replicative complex components (origin recognition complex [ORC] and minichromosome maintenance [MCM] complex). Depletion of Kdm4d impairs the recruitment of Cdc45, proliferating cell nuclear antigen (PCNA), and polymerase δ, but not ORC and MCM proteins. These results demonstrate a novel mechanism by which Kdm4d regulates DNA replication by reducing the H3K9me3 level to facilitate formation of pre-initiative complex. PMID:27679476

Planification de la maintenance d'un parc de turbines-alternateurs par programmation mathematique

NASA Astrophysics Data System (ADS)

Aoudjit, Hakim

A growing number of Hydro-Quebec's hydro generators are at the end of their useful life and maintenance managers fear to face a number of overhauls exceeding what can be handled. Maintenance crews and budgets are limited and these withdrawals may take up to a full year and mobilize significant resources in addition to the loss of electricity production. In addition, increased export sales forecasts and severe production patterns are expected to speed up wear that can lead to halting many units at the same time. Currently, expert judgment is at the heart of withdrawals which rely primarily on periodic inspections and in-situ measurements and the results are sent to the maintenance planning team who coordinate all the withdrawals decisions. The degradations phenomena taking place is random in nature and the prediction capability of wear using only inspections is limited to short-term at best. A long term planning of major overhauls is sought by managers for the sake of justifying and rationalizing budgets and resources. The maintenance managers are able to provide a huge amount of data. Among them, is the hourly production of each unit for several years, the repairs history on each part of a unit as well as major withdrawals since the 1950's. In this research, we tackle the problem of long term maintenance planning for a fleet of 90 hydro generators at Hydro-Quebec over a 50 years planning horizon period. We lay a scientific and rational framework to support withdrawals decisions by using part of the available data and maintenance history while fulfilling a set of technical and economic constraints. We propose a planning approach based on a constrained optimization framework. We begin by decomposing and sorting hydro generator components to highlight the most influential parts. A failure rate model is developed to take into account the technical characteristics and unit utilization. Then, replacement and repair policies are evaluated for each of the components then strategies are derived for the whole unit. Traditional univariate policies such as the age replacement policy and the minimal repair policy are calculated. These policies are extended to build alternative bivariate maintenance policy as well as a repair strategy where the state of a component after a repair is rejuvenated by a constant coefficient. These templates form the basis for the calculation of objective function for the scheduling problem. On one hand, this issue is treated as a nonlinear problem where the objective is to minimize the average total maintenance cost per unit of time on an infinite horizon for the fleet with technical and economic constraints. A formulation is also proposed in the case of a finite time horizon. In the event of electricity production variation, and given that the usage profile is known, the influence of production scenarios is reflected on the unit's components through their failure rate. In this context, prognoses on possible resources problems are made by studying the characteristics of the generated plans. On the second hand, the withdrawals are now subjected to two decision criteria. In addition to minimizing the average total maintenance cost per unit of time on an infinite time horizon, the best achievable reliability of remaining turbo generators is sought. This problem is treated as a biobjective nonlinear optimization problem. Finally a series of problems describing multiple contexts are solved for planning renovations of 90 turbo generators units considering 3 major components in each unit and 2 types of maintenance policies for each component.

AUTOMOTIVE DIESEL MAINTENANCE 1. UNIT IV, MAINTAINING THE COOLING SYSTEM--DETROIT DIESEL ENGINES.

ERIC Educational Resources Information Center

Human Engineering Inst., Cleveland, OH.

THIS MODULE OF A 30-MODULE COURSE IS DESIGNED TO DEVELOP AN UNDERSTANDING OF THE OPERATION AND MAINTENANCE OF THE DIESEL ENGINE COOLING SYSTEM. TOPICS ARE PURPOSE OF THE COOLING SYSTEM, CARE MAINTENANCE OF THE COOLING SYSTEM, COOLING SYSTEM COMPONENTS, AND TROUBLESHOOTING TIPS. THE MODULE CONSISTS OF A SELF-INSTRUCTIONAL BRANCH PROGRAMED TRAINING…

Two Heteromeric Kinesin Complexes in Chemosensory Neurons and Sensory Cilia of Caenorhabditis elegans

PubMed Central

Signor, Dawn; Wedaman, Karen P.; Rose, Lesilee S.; Scholey, Jonathan M.

1999-01-01

Chemosensation in the nervous system of the nematode Caenorhabditis elegans depends on sensory cilia, whose assembly and maintenance requires the transport of components such as axonemal proteins and signal transduction machinery to their site of incorporation into ciliary structures. Members of the heteromeric kinesin family of microtubule motors are prime candidates for playing key roles in these transport events. Here we describe the molecular characterization and partial purification of two heteromeric kinesin complexes from C. elegans, heterotrimeric CeKinesin-II and dimeric CeOsm-3. Transgenic worms expressing green fluorescent protein driven by endogenous heteromeric kinesin promoters reveal that both CeKinesin-II and CeOsm-3 are expressed in amphid, inner labial, and phasmid chemosensory neurons. Additionally, immunolocalization experiments on fixed worms show an intense concentration of CeKinesin-II and CeOsm-3 polypeptides in the ciliated endings of these chemosensory neurons and a punctate localization pattern in the corresponding cell bodies and dendrites. These results, together with the phenotypes of known mutants in the pathway of sensory ciliary assembly, suggest that CeKinesin-II and CeOsm-3 drive the transport of ciliary components required for sequential steps in the assembly of chemosensory cilia. PMID:9950681

Magmas functions as a ROS regulator and provides cytoprotection against oxidative stress-mediated damages

PubMed Central

Srivastava, S; Sinha, D; Saha, P P; Marthala, H; D'Silva, P

2014-01-01

Redox imbalance generates multiple cellular damages leading to oxidative stress-mediated pathological conditions such as neurodegenerative diseases and cancer progression. Therefore, maintenance of reactive oxygen species (ROS) homeostasis is most important that involves well-defined antioxidant machinery. In the present study, we have identified for the first time a component of mammalian protein translocation machinery Magmas to perform a critical ROS regulatory function. Magmas overexpression has been reported in highly metabolically active tissues and cancer cells that are prone to oxidative damage. We found that Magmas regulates cellular ROS levels by controlling its production as well as scavenging. Magmas promotes cellular tolerance toward oxidative stress by enhancing antioxidant enzyme activity, thus preventing induction of apoptosis and damage to cellular components. Magmas enhances the activity of electron transport chain (ETC) complexes, causing reduced ROS production. Our results suggest that J-like domain of Magmas is essential for maintenance of redox balance. The function of Magmas as a ROS sensor was found to be independent of its role in protein import. The unique ROS modulatory role of Magmas is highlighted by its ability to increase cell tolerance to oxidative stress even in yeast model organism. The cytoprotective capability of Magmas against oxidative damage makes it an important candidate for future investigation in therapeutics of oxidative stress-related diseases. PMID:25165880

Morphofunctional aspects of the blood-brain barrier.

PubMed

Nico, Beatrice; Ribatti, Domenico

2012-01-01

The blood-brain barrier (BBB) selectively controls the homeostasis of the Central Nervous System (CNS) environment by the specific structural and biochemical features of the endothelial cells, pericytes and glial endfeet, which represent the cellular components of the mature BBB. Endothelial tight junctions (TJs) are the most important structural component of the BBB, and molecular alteration in the phosphorylation state of some TJs proteins, like ZO-1 or occludin, are crucial in determining alterations in the control of BBB vascular permeability. Astrocytes endfeet enveloping the vessels wall, are considered important in the induction and maintenance of the BBB, through secretion of soluble factors, which modulate the expression of enzymatic complexes and antigens by endothelial cells and TJs - associated proteins. Moreover, astrocytes control water flux at BBB site by expressing a specific water channel, namely aquaporin-4 (AQP4), involved in the molecular composition of the orthogonal particles arrays (OAPs) on the perivascular glial endfeet and tightly coupled with the maintenance of the BBB integrity. Disruption of the BBB is a consistent event occurring in the development of several CNS diseases, including demyelinating lesions in the course of relapsing multiple sclerosis, stroke, Duchenne muscular dystrophy (DMD), but also mechanical injures, neurological insults, septic encephalopathy, brain tumors, permanent ischemia or transient ischemia followed by reperfusion. In most cases, these pathological conditions are associated with an increase in microvascular permeability, vasogenic edema, swollen atrocyte endfeet, and BBB disruption.

Laboratory equipment maintenance contracts.

PubMed

Boudreau, D A; Scheer, W D; Catrou, P G

1985-12-01

The increasing level of technical sophistication and complexity found in clinical laboratory instrumentation today more than ever demands careful attention to maintenance service needs. The time-worn caution for careful definition of requirements for acquisition of a system should also carry over to acquisition of maintenance service. Guidelines are presented for specifications of terms and conditions for maintenance service from the perspective of the laboratorian in the automated clinical laboratory.

RT-Syn: A real-time software system generator

NASA Technical Reports Server (NTRS)

Setliff, Dorothy E.

1992-01-01

This paper presents research into providing highly reusable and maintainable components by using automatic software synthesis techniques. This proposal uses domain knowledge combined with automatic software synthesis techniques to engineer large-scale mission-critical real-time software. The hypothesis centers on a software synthesis architecture that specifically incorporates application-specific (in this case real-time) knowledge. This architecture synthesizes complex system software to meet a behavioral specification and external interaction design constraints. Some examples of these external constraints are communication protocols, precisions, timing, and space limitations. The incorporation of application-specific knowledge facilitates the generation of mathematical software metrics which are used to narrow the design space, thereby making software synthesis tractable. Success has the potential to dramatically reduce mission-critical system life-cycle costs not only by reducing development time, but more importantly facilitating maintenance, modifications, and extensions of complex mission-critical software systems, which are currently dominating life cycle costs.

Cadherins and Their Partners in the Nematode Worm Caenorhabditis elegans

PubMed Central

Hardin, Jeff; Lynch, Allison; Loveless, Timothy; Pettitt, Jonathan

2018-01-01

The extreme simplicity of Caenorhabditis elegans makes it an ideal system to study the basic principles of cadherin function at the level of single cells within the physiologically relevant context of a developing animal. The genetic tractability of C. elegans also means that components of cadherin complexes can be identified through genetic modifier screens, allowing a comprehensive in vivo characterization of the macromolecular assemblies involved in cadherin function during tissue formation and maintenance in C. elegans. This work shows that a single cadherin system, the classical cadherin–catenin complex, is essential for diverse morphogenetic events during embryogenesis through its interactions with a range of mostly conserved proteins that act to modulate its function. The role of other members of the cadherin family in C. elegans, including members of the Fat-like, Flamingo/CELSR and calsyntenin families is less well characterized, but they have clear roles in neuronal development and function. PMID:23481198

A Novel Passive Robotic Tool Interface

NASA Astrophysics Data System (ADS)

Roberts, Paul

2013-09-01

The increased capability of space robotics has seen their uses increase from simple sample gathering and mechanical adjuncts to humans, to sophisticated multi- purpose investigative and maintenance tools that substitute for humans for many external space tasks. As with all space missions, reducing mass and system complexity is critical. A key component of robotic systems mass and complexity is the number of motors and actuators needed. MDA has developed a passive tool interface that, like a household power drill, permits a single tool actuator to be interfaced with many Tool Tips without requiring additional actuators to manage the changing and storage of these tools. MDA's Multifunction Tool interface permits a wide range of Tool Tips to be designed to a single interface that can be pre-qualified to torque and strength limits such that additional Tool Tips can be added to a mission's "tool kit" simply and quickly.

Regulation of the mammalian heat shock factor 1.

PubMed

Dayalan Naidu, Sharadha; Dinkova-Kostova, Albena T

2017-06-01

Living organisms are endowed with the capability to tackle various forms of cellular stress due to the presence of molecular chaperone machinery complexes that are ubiquitous throughout the cell. During conditions of proteotoxic stress, the transcription factor heat shock factor 1 (HSF1) mediates the elevation of heat shock proteins, which are crucial components of the chaperone complex machinery and function to ameliorate protein misfolding and aggregation and restore protein homeostasis. In addition, HSF1 orchestrates a versatile transcriptional programme that includes genes involved in repair and clearance of damaged macromolecules and maintenance of cell structure and metabolism, and provides protection against a broad range of cellular stress mediators, beyond heat shock. Here, we discuss the structure and function of the mammalian HSF1 and its regulation by post-translational modifications (phosphorylation, sumoylation and acetylation), proteasomal degradation, and small-molecule activators and inhibitors. © 2017 Federation of European Biochemical Societies.

SSB as an organizer/mobilizer of genome maintenance complexes

PubMed Central

Shereda, Robert D.; Kozlov, Alexander G.; Lohman, Timothy M.; Cox, Michael M.; Keck, James L.

2008-01-01

When duplex DNA is altered in almost any way (replicated, recombined, or repaired), single strands of DNA are usually intermediates, and single-stranded DNA binding (SSB) proteins are present. These proteins have often been described as inert, protective DNA coatings. Continuing research is demonstrating a far more complex role of SSB that includes the organization and/or mobilization of all aspects of DNA metabolism. Escherichia coli SSB is now known to interact with at least 14 other proteins that include key components of the elaborate systems involved in every aspect of DNA metabolism. Most, if not all, of these interactions are mediated by the amphipathic C-terminus of SSB. In this review, we summarize the extent of the eubacterial SSB interaction network, describe the energetics of interactions with SSB, and highlight the roles of SSB in the process of recombination. Similar themes to those highlighted in this review are evident in all biological systems. PMID:18937104

Building Component Maintenance and Repair Data Base: Heating, Ventilating, and Air Conditioning (HVAC) Systems

DTIC Science & Technology

1991-05-01

Building Component Maintenance and Repair Data Base: Heating, Ventilating, and Air Conditioning (HVAC) Systems by Edgar S. Neely Robert D. Neathammer...Repair Data Base: Heating, Ventilating, and Air Conditioning (HVAC) Systems RDTE dated 1980EIMB 1984 - 1989 6. AUTHOR(S) Edgar S. Neely, Robert D...Laboratory (USACERL). The Principal Investigators were Dr. Edgar Neely and Mr. Robert Neathammer (USACERL-FS). The primary contractor for much of the

INVOLVED IN DE NOVO 2-containing complex involved in RNA-directed DNA methylation in Arabidopsis

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

Ausin, Israel; Greenberg, Maxim V.C.; Simanshu, Dhirendra K.

2012-10-23

At least three pathways control maintenance of DNA cytosine methylation in Arabidopsis thaliana. However, the RNA-directed DNA methylation (RdDM) pathway is solely responsible for establishment of this silencing mark. We previously described INVOLVED IN DE NOVO 2 (IDN2) as being an RNA-binding RdDM component that is required for DNA methylation establishment. In this study, we describe the discovery of two partially redundant proteins that are paralogous to IDN2 and that form a stable complex with IDN2 in vivo. Null mutations in both genes, termed IDN2-LIKE 1 and IDN2-LIKE 2 (IDNL1 and IDNL2), result in a phenotype that mirrors, but doesmore » not further enhance, the idn2 mutant phenotype. Genetic analysis suggests that this complex acts in a step in the downstream portion of the RdDM pathway. We also have performed structural analysis showing that the IDN2 XS domain adopts an RNA recognition motif (RRM) fold. Finally, genome-wide DNA methylation and expression analysis confirms the placement of the IDN proteins in an RdDM pathway that affects DNA methylation and transcriptional control at many sites in the genome. Results from this study identify and describe two unique components of the RdDM machinery, adding to our understanding of DNA methylation control in the Arabidopsis genome.« less

Risk-informed Maintenance for Non-coherent Systems

NASA Astrophysics Data System (ADS)

Tao, Ye

Probabilistic Safety Assessment (PSA) is a systematic and comprehensive methodology to evaluate risks associated with a complex engineered technological entity. The information provided by PSA has been increasingly implemented for regulatory purposes but rarely used in providing information for operation and maintenance activities. As one of the key parts in PSA, Fault Tree Analysis (FTA) attempts to model and analyze failure processes of engineering and biological systems. The fault trees are composed of logic diagrams that display the state of the system and are constructed using graphical design techniques. Risk Importance Measures (RIMs) are information that can be obtained from both qualitative and quantitative aspects of FTA. Components within a system can be ranked with respect to each specific criterion defined by each RIM. Through a RIM, a ranking of the components or basic events can be obtained and provide valuable information for risk-informed decision making. Various RIMs have been applied in various applications. In order to provide a thorough understanding of RIMs and interpret the results, they are categorized with respect to risk significance (RS) and safety significance (SS) in this thesis. This has also tied them into different maintenance activities. When RIMs are used for maintenance purposes, it is called risk-informed maintenance. On the other hand, the majority of work produced on the FTA method has been concentrated on failure logic diagrams restricted to the direct or implied use of AND and OR operators. Such systems are considered as coherent systems. However, the NOT logic can also contribute to the information produced by PSA. The importance analysis of non-coherent systems is rather limited, even though the field has received more and more attention over the years. The non-coherent systems introduce difficulties in both qualitative and quantitative assessment of the fault tree compared with the coherent systems. In this thesis, a set of RIMs is analyzed and investigated. The 8 commonly used RIMs (Birnbaum's Measure, Criticality Importance Factor, Fussell-Vesely Measure, Improvement Potential, Conditional Probability, Risk Achievement, Risk Achievement Worth, and Risk Reduction Worth) are extended to non-coherent forms. Both coherent and non-coherent forms are classified into different categories in order to assist different types of maintenance activities. The real systems such as the Steam Generator Level Control System in CANDU Nuclear Power Plant (NPP), a Gas Detection System, and the Automatic Power Control System of the experimental nuclear reactor are presented to demonstrate the application of the results as case studies.

AUTOMOTIVE DIESEL MAINTENANCE 1. UNIT III, MAINTAINING THE FUEL SYSTEM--DETROIT DIESEL ENGINE.

ERIC Educational Resources Information Center

Human Engineering Inst., Cleveland, OH.

THIS MODULE OF A 30-MODULE COURSE IS DESIGNED TO DEVELOP AN UNDERSTANDING OF THE OPERATION AND MAINTENANCE OF THE DIESEL ENGINE FUEL SYSTEM. TOPICS ARE (1) PURPOSE OF THE FUEL SYSTEM, (2) TRACING THE FUEL FLOW, (3) MINOR COMPONENTS OF THE FUEL SYSTEM, (4) MAINTENANCE TIPS, (5) CONSTRUCTION AND FUNCTION OF THE FUEL INJECTORS, AND (6)…

40 CFR 1048.410 - How must I select, prepare, and test my in-use engines?

Code of Federal Regulations, 2010 CFR

2010-07-01

... or used in an abnormal way; and (3) Documented in terms of total hours of operation, maintenance... comply before testing a total of ten engines. (d) You may do minimal maintenance to set components of a...)). Limit maintenance to what is in the owner's instructions for engines with that amount of service and age...

77 FR 46285 - Drawbridge Operation Regulation; Inner Harbor Navigational Canal, New Orleans, LA

Federal Register 2010, 2011, 2012, 2013, 2014

2012-08-03

... cables, and for the rehabilitation of most electrical motors and components, most mechanical components... mechanical components and the operator house. This maintenance is essential for the continued operation of...

DATMAN: A reliability data analysis program using Bayesian updating

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

Becker, M.; Feltus, M.A.

1996-12-31

Preventive maintenance (PM) techniques focus on the prevention of failures, in particular, system components that are important to plant functions. Reliability-centered maintenance (RCM) improves on the PM techniques by introducing a set of guidelines by which to evaluate the system functions. It also minimizes intrusive maintenance, labor, and equipment downtime without sacrificing system performance when its function is essential for plant safety. Both the PM and RCM approaches require that system reliability data be updated as more component failures and operation time are acquired. Systems reliability and the likelihood of component failures can be calculated by Bayesian statistical methods, whichmore » can update these data. The DATMAN computer code has been developed at Penn State to simplify the Bayesian analysis by performing tedious calculations needed for RCM reliability analysis. DATMAN reads data for updating, fits a distribution that best fits the data, and calculates component reliability. DATMAN provides a user-friendly interface menu that allows the user to choose from several common prior and posterior distributions, insert new failure data, and visually select the distribution that matches the data most accurately.« less

Evaluation of Hands-Free Devices for the Display of Maintenance Procedures

NASA Technical Reports Server (NTRS)

Whitmore, Mihriban; Hoffman, Ronald B.; Litaker, Harry, Jr.; Solem, Jody; Holden, Kritina; Twyford, Evan; Conlee, Carl

2007-01-01

Over the past year, NASA's focus has turned to crewed long duration and exploration missions. On these journeys, crewmembers will be required to execute thousands of procedures to maintain life support systems, check out space suits, conduct science experiments, and perform medical exams. To support the many complex tasks crewmembers undertake in microgravity, NASA is interested in providing crewmembers a hands-free work environment to promote more efficient operations. The overarching objective is to allow crewmembers to use both of their hands for tasks related to their mission, versus holding a paper manual or interacting with a display. The use of advanced, hands-free tools will undoubtedly make the crewmembers task easier, but they can also add to overall task complexity if not properly designed. A leading candidate technology for supporting a hands-free environment is the Head-Mounted Display (HMD). A more recent technology (e-book reader) that could be easily temp-stowed near the work area is also a potential hands-free solution. Previous work at NASA involved the evaluation of several commercially available HMDs for visual quality, comfort, and fit, as well as suitability for use in microgravity. Based on results from this work, three HMDs were selected for further evaluation (along with an e-book reader), using International Space Station (ISS)-like maintenance procedures. Two evaluations were conducted in the Space Station Mockup and Trainer Facility (SSMTF) located at the NASA Johnson Space Center (building 9). The SSMTF is a full scale, medium fidelity replica of the pressurized portions of the ISS. It supports crew training such as ingress and egress, habitability, and emergency procedures. In each of the two evaluations, the participants performed two maintenance procedures. One maintenance procedure involved inspecting air filters in a life support system and replacing them with a clean filter if one were found to be contaminated. The second maintenance procedure focused on working in a confined space; specifically, pulling down a rack to inspect wiring configurations, and rewiring in a different pattern. The maintenance procedures were selected to assess mobility, tool use, and access to multiple document sources during task performance. That is, the participant had to move from rack to rack, use a wrench, a camera, etc., replace components, and refer to diagrams to complete tasks. A constraint was imposed that the ISS-like format of the procedures was to be retained, and not modified or optimized for the electronic device ("plug and play" approach). This was based on future plans to test with real procedures on ISS.

Gene Network Polymorphism Illuminates Loss and Retention of Novel RNAi Silencing Components in the Cryptococcus Pathogenic Species Complex.

PubMed

Feretzaki, Marianna; Billmyre, R Blake; Clancey, Shelly Applen; Wang, Xuying; Heitman, Joseph

2016-03-01

RNAi is a ubiquitous pathway that serves central functions throughout eukaryotes, including maintenance of genome stability and repression of transposon expression and movement. However, a number of organisms have lost their RNAi pathways, including the model yeast Saccharomyces cerevisiae, the maize pathogen Ustilago maydis, the human pathogen Cryptococcus deuterogattii, and some human parasite pathogens, suggesting there may be adaptive benefits associated with both retention and loss of RNAi. By comparing the RNAi-deficient genome of the Pacific Northwest Outbreak C. deuterogattii strain R265 with the RNAi-proficient genomes of the Cryptococcus pathogenic species complex, we identified a set of conserved genes that were lost in R265 and all other C. deuterogattii isolates examined. Genetic and molecular analyses reveal several of these lost genes play roles in RNAi pathways. Four novel components were examined further. Znf3 (a zinc finger protein) and Qip1 (a homolog of N. crassa Qip) were found to be essential for RNAi, while Cpr2 (a constitutive pheromone receptor) and Fzc28 (a transcription factor) are involved in sex-induced but not mitosis-induced silencing. Our results demonstrate that the mitotic and sex-induced RNAi pathways rely on the same core components, but sex-induced silencing may be a more specific, highly induced variant that involves additional specialized or regulatory components. Our studies further illustrate how gene network polymorphisms involving known components of key cellular pathways can inform identification of novel elements and suggest that RNAi loss may have been a core event in the speciation of C. deuterogattii and possibly contributed to its pathogenic trajectory.

Cancer incidence and mortality among temporary maintenance workers in a refinery/petrochemical complex in Korea.

PubMed

Koh, Dong-Hee; Chung, Eun-Kyo; Jang, Jae-Kil; Lee, Hye-Eun; Ryu, Hyang-Woo; Yoo, Kye-Mook; Kim, Eun-A; Kim, Kyoo-Sang

2014-01-01

Petrochemical plant maintenance workers are exposed to various carcinogens such as benzene and metal fumes. In Korea, maintenance operations in petrochemical plants are typically performed by temporary employees hired as contract workers. The purpose of this retrospective study was to evaluate cancer risk in temporary maintenance workers in a refinery/petrochemical complex in Korea. Subjects consisted of 14 698 male workers registered in a regional petrochemical plant maintenance workers union during 2002-2007. Cancer mortality and incidence were identified by linking with the nationwide death and cancer registries during 2002-2007 and 2002-2005, respectively. Standardized mortality ratios (SMRs) and standardized incidence ratios (SIRs) were calculated for each cancer. Increased SMR 3·61 (six cases, 95% CI: 1·32-7·87) and SIR 3·18 (five cases, 95% CI: 1·03-7·42) were observed in oral and pharyngeal cancers. Our findings may suggest a potential association between oral and pharyngeal cancers and temporary maintenance jobs in the petrochemical industry. Future studies should include a longer follow-up period and a quantitative exposure assessment.

Two Different Maintenance Strategies in the Hospital Environment: Preventive Maintenance for Older Technology Devices and Predictive Maintenance for Newer High-Tech Devices.

PubMed

Sezdi, Mana

2016-01-01

A maintenance program generated through the consideration of characteristics and failures of medical equipment is an important component of technology management. However, older technology devices and newer high-tech devices cannot be efficiently managed using the same strategies because of their different characteristics. This study aimed to generate a maintenance program comprising two different strategies to increase the efficiency of device management: preventive maintenance for older technology devices and predictive maintenance for newer high-tech devices. For preventive maintenance development, 589 older technology devices were subjected to performance verification and safety testing (PVST). For predictive maintenance development, the manufacturers' recommendations were used for 134 high-tech devices. These strategies were evaluated in terms of device reliability. This study recommends the use of two different maintenance strategies for old and new devices at hospitals in developing countries. Thus, older technology devices that applied only corrective maintenance will be included in maintenance like high-tech devices.

Two Different Maintenance Strategies in the Hospital Environment: Preventive Maintenance for Older Technology Devices and Predictive Maintenance for Newer High-Tech Devices

PubMed Central

Sezdi, Mana

2016-01-01

A maintenance program generated through the consideration of characteristics and failures of medical equipment is an important component of technology management. However, older technology devices and newer high-tech devices cannot be efficiently managed using the same strategies because of their different characteristics. This study aimed to generate a maintenance program comprising two different strategies to increase the efficiency of device management: preventive maintenance for older technology devices and predictive maintenance for newer high-tech devices. For preventive maintenance development, 589 older technology devices were subjected to performance verification and safety testing (PVST). For predictive maintenance development, the manufacturers' recommendations were used for 134 high-tech devices. These strategies were evaluated in terms of device reliability. This study recommends the use of two different maintenance strategies for old and new devices at hospitals in developing countries. Thus, older technology devices that applied only corrective maintenance will be included in maintenance like high-tech devices. PMID:27195666

Built-In Data-Flow Integration Testing in Large-Scale Component-Based Systems

NASA Astrophysics Data System (ADS)

Piel, Éric; Gonzalez-Sanchez, Alberto; Gross, Hans-Gerhard

Modern large-scale component-based applications and service ecosystems are built following a number of different component models and architectural styles, such as the data-flow architectural style. In this style, each building block receives data from a previous one in the flow and sends output data to other components. This organisation expresses information flows adequately, and also favours decoupling between the components, leading to easier maintenance and quicker evolution of the system. Integration testing is a major means to ensure the quality of large systems. Their size and complexity, together with the fact that they are developed and maintained by several stake holders, make Built-In Testing (BIT) an attractive approach to manage their integration testing. However, so far no technique has been proposed that combines BIT and data-flow integration testing. We have introduced the notion of a virtual component in order to realize such a combination. It permits to define the behaviour of several components assembled to process a flow of data, using BIT. Test-cases are defined in a way that they are simple to write and flexible to adapt. We present two implementations of our proposed virtual component integration testing technique, and we extend our previous proposal to detect and handle errors in the definition by the user. The evaluation of the virtual component testing approach suggests that more issues can be detected in systems with data-flows than through other integration testing approaches.

The absence of chlorophyll b affects lateral mobility of photosynthetic complexes and lipids in grana membranes of Arabidopsis and barley chlorina mutants.

PubMed

Tyutereva, Elena V; Evkaikina, Anastasiia I; Ivanova, Alexandra N; Voitsekhovskaja, Olga V

2017-09-01

The lateral mobility of integral components of thylakoid membranes, such as plastoquinone, xanthophylls, and pigment-protein complexes, is critical for the maintenance of efficient light harvesting, high rates of linear electron transport, and successful repair of damaged photosystem II (PSII). The packaging of the photosynthetic pigment-protein complexes in the membrane depends on their size and stereometric parameters which in turn depend on the composition of the complexes. Chlorophyll b (Chlb) is an important regulator of antenna size and composition. In this study, the lateral mobility (the mobile fraction size) of pigment-protein complexes and lipids in grana membranes was analyzed in chlorina mutants of Arabidopsis and barley lacking Chlb. In the Arabidopsis ch1-3 mutant, diffusion of membrane lipids decreased as compared to wild-type plants, but the diffusion of photosynthetic complexes was not affected. In the barley chlorina f2 3613 mutant, the diffusion of pigment-protein complexes significantly decreased, while the diffusion of lipids increased, as compared to wild-type plants. We propose that the size of the mobile fractions of pigment-protein complexes in grana membranes in vivo is higher than reported previously. The data are discussed in the context of the protein composition of antennae, characteristics of the plastoquinone pool, and production of reactive oxygen species in leaves of chlorina mutants.

MDOT Pavement Management System : Prediction Models and Feedback System

DOT National Transportation Integrated Search

2000-10-01

As a primary component of a Pavement Management System (PMS), prediction models are crucial for one or more of the following analyses: : maintenance planning, budgeting, life-cycle analysis, multi-year optimization of maintenance works program, and a...

FRAMEWORK FOR STRUCTURAL ONLINE HEALTH MONITORING OF AGING AND DEGRADATION OF SECONDARY PIPING SYSTEMS DUE TO SOME ASPECTS OF EROSION

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

Gribok, Andrei V.; Agarwal, Vivek

This paper describes the current state of research related to critical aspects of erosion and selected aspects of degradation of secondary components in nuclear power plants (NPPs). The paper also proposes a framework for online health monitoring of aging and degradation of secondary components. The framework consists of an integrated multi-sensor modality system, which can be used to monitor different piping configurations under different degradation conditions. The report analyses the currently known degradation mechanisms and available predictive models. Based on this analysis, the structural health monitoring framework is proposed. The Light Water Reactor Sustainability Program began to evaluate technologies thatmore » could be used to perform online monitoring of piping and other secondary system structural components in commercial NPPs. These online monitoring systems have the potential to identify when a more detailed inspection is needed using real time measurements, rather than at a pre-determined inspection interval. This transition to condition-based, risk-informed automated maintenance will contribute to a significant reduction of operations and maintenance costs that account for the majority of nuclear power generation costs. Furthermore, of the operations and maintenance costs in U.S. plants, approximately 80% are labor costs. To address the issue of rising operating costs and economic viability, in 2017, companies that operate the national nuclear energy fleet started the Delivering the Nuclear Promise Initiative, which is a 3 year program aimed at maintaining operational focus, increasing value, and improving efficiency. There is unanimous agreement between industry experts and academic researchers that identifying and prioritizing inspection locations in secondary piping systems (for example, in raw water piping or diesel piping) would eliminate many excessive in-service inspections. The proposed structural health monitoring framework takes aim at answering this challenge by combining long range guided wave technologies with other monitoring techniques, which can significantly increase the inspection length and pinpoint the locations that degraded the most. More widely, the report suggests research efforts aimed at developing, validating, and deploying online corrosion monitoring techniques for complex geometries, which are pervasive in NPPs.« less

Nuclear reactor insulation and preheat system

DOEpatents

Wampole, Nevin C.

1978-01-01

An insulation and preheat system for preselected components of a fluid cooled nuclear reactor. A gas tight barrier or compartment of thermal insulation surrounds the selected components and includes devices to heat the internal atmosphere of the compartment. An external surface of the compartment or enclosure is cooled, such as by a circulating fluid. The heating devices provide for preheating of the components, as well as maintenance of a temperature sufficient to ensure that the reactor coolant fluid will not solidify during shutdown. The external cooling limits the heat transferred to other plant structures, such as supporting concrete and steel. The barrier is spaced far enough from the surrounded components so as to allow access for remote or manual inspection, maintenance, and repair.

The moving-ring field-reversed mirror prototype reactor

NASA Astrophysics Data System (ADS)

Smith, A. C., Jr.; Carlson, G. A.; Fleischmann, H. H.; Grossman, W., Jr.; Kammash, T.; Schultz, K. R.; Woodall, D. M.

1981-03-01

A prototype fusion reactor was designed based on magnetic field reversed plasma confinement. A set of physics, technology, and mechanical design criteria were developed in order to make this concept attractive. Six major criteria guide the commercial prototype design. The prototype must: (1) produce net electricity decisively P sub net 70% of P sub gross; (2) scale to an economical commercial plant and have small physical size; (3) have all features required of a correcial upgrade plant (H-3 breeding, etc.); (4) minimize exotic technology and maintenance complexity; (5) promise significantly lower safety hazards than fission plants (environmentally and socially acceptable); and (6) be modular in design to permit repetitive production of components.

Utilization of artificial intelligence techniques for the Space Station power system

NASA Technical Reports Server (NTRS)

Evatt, Thomas C.; Gholdston, Edward W.

1988-01-01

Due to the complexity of the Space Station Electrical Power System (EPS) as currently envisioned, artificial intelligence/expert system techniques are being investigated to automate operations, maintenance, and diagnostic functions. A study was conducted to investigate this technology as it applies to failure detection, isolation, and reconfiguration (FDIR) and health monitoring of power system components and of the total system. Control system utilization of expert systems for load scheduling and shedding operations was also researched. A discussion of the utilization of artificial intelligence/expert systems for Initial Operating Capability (IOC) for the Space Station effort is presented along with future plans at Rocketdyne for the utilization of this technology for enhanced Space Station power capability.

The Chromatin Remodeler BPTF Activates a Stemness Gene-Expression Program Essential for the Maintenance of Adult Hematopoietic Stem Cells.

PubMed

Xu, Bowen; Cai, Ling; Butler, Jason M; Chen, Dongliang; Lu, Xiongdong; Allison, David F; Lu, Rui; Rafii, Shahin; Parker, Joel S; Zheng, Deyou; Wang, Gang Greg

2018-03-13

Self-renewal and differentiation of adult stem cells are tightly regulated partly through configuration of chromatin structure by chromatin remodelers. Using knockout mice, we here demonstrate that bromodomain PHD finger transcription factor (BPTF), a component of the nucleosome remodeling factor (NURF) chromatin-remodeling complex, is essential for maintaining the population size of hematopoietic stem/progenitor cells (HSPCs), including long-term hematopoietic stem cells (HSCs). Bptf-deficient HSCs are defective in reconstituted hematopoiesis, and hematopoietic-specific knockout of Bptf caused profound defects including bone marrow failure and anemia. Genome-wide transcriptome profiling revealed that BPTF loss caused downregulation of HSC-specific gene-expression programs, which contain several master transcription factors (Meis1, Pbx1, Mn1, and Lmo2) required for HSC maintenance and self-renewal. Furthermore, we show that BPTF potentiates the chromatin accessibility of key HSC "stemness" genes. These results demonstrate an essential requirement of the chromatin remodeler BPTF and NURF for activation of "stemness" gene-expression programs and proper function of adult HSCs. Copyright © 2018 The Author(s). Published by Elsevier Inc. All rights reserved.

Stage- and subunit-specific functions of polycomb repressive complex 2 in bladder urothelial formation and regeneration

PubMed Central

Guo, Chunming; Balsara, Zarine R.

2017-01-01

ABSTRACT Urothelium is the protective lining of the urinary tract. The mechanisms underlying urothelial formation and maintenance are largely unknown. Here, we report the stage-specific roles of PRC2 epigenetic regulators in embryonic and adult urothelial progenitors. Without Eed, the obligatory subunit of PRC2, embryonic urothelial progenitors demonstrate reduced proliferation with concomitant dysregulation of genes including Cdkn2a (p16), Cdkn2b (p15) and Shh. These mutants display premature differentiation of keratin 5-positive (Krt5+) basal cells and ectopic expression of squamous-like differentiation markers. Deletion of Ezh2, the major enzymatic component of PRC2, causes upregulation of Upk3a+ superficial cells. Unexpectedly, Eed and Eed/Ezh2 double mutants exhibit delayed superficial cell differentiation. Furthermore, Eed regulates the proliferative and regenerative capacity of adult urothelial progenitors and prevents precocious differentiation. Collectively, these findings uncover the epigenetic mechanism by which PRC2 controls urothelial progenitor cell fate and the timing of differentiation, and further suggest an epigenetic basis of urothelial maintenance and regeneration. PMID:28049658

Phase editing as a signal pre-processing step for automated bearing fault detection

NASA Astrophysics Data System (ADS)

Barbini, L.; Ompusunggu, A. P.; Hillis, A. J.; du Bois, J. L.; Bartic, A.

2017-07-01

Scheduled maintenance and inspection of bearing elements in industrial machinery contributes significantly to the operating costs. Savings can be made through automatic vibration-based damage detection and prognostics, to permit condition-based maintenance. However automation of the detection process is difficult due to the complexity of vibration signals in realistic operating environments. The sensitivity of existing methods to the choice of parameters imposes a requirement for oversight from a skilled operator. This paper presents a novel approach to the removal of unwanted vibrational components from the signal: phase editing. The approach uses a computationally-efficient full-band demodulation and requires very little oversight. Its effectiveness is tested on experimental data sets from three different test-rigs, and comparisons are made with two state-of-the-art processing techniques: spectral kurtosis and cepstral pre- whitening. The results from the phase editing technique show a 10% improvement in damage detection rates compared to the state-of-the-art while simultaneously improving on the degree of automation. This outcome represents a significant contribution in the pursuit of fully automatic fault detection.

AUTOMOTIVE DIESEL MAINTENANCE 1. UNIT XXII, I--MAINTAINING THE FUEL SYSTEM (PART I)--CUMMINS DIESEL ENGINE, II--UNDERSTANDING THE DIFFERENTIAL.

ERIC Educational Resources Information Center

Minnesota State Dept. of Education, St. Paul. Div. of Vocational and Technical Education.

THIS MODULE OF A 30-MODULE COURSE IS DESIGNED TO DEVELOP AN UNDERSTANDING OF THE FUNCTION AND MAINTENANCE OF THE DIESEL ENGINE FUEL SYSTEM AND DIFFERENTIAL DRIVE UNITS USED IN DIESEL POWERED VEHICLES. TOPICS ARE (1) FUEL SYSTEM COMPARISONS, (2) FUEL SYSTEM SUPPLY COMPONENTS, (3) FUEL SUPPLY SECTION MAINTENANCE, (4) FUNCTION OF THE DIFFERENTIAL,…

Burbank performs the WHC Yearly Maintenance in the Node 3

NASA Image and Video Library

2012-01-11

ISS030-E-032750 (11 Jan. 2012) --- NASA astronaut Dan Burbank, Expedition 30 flight commander, performs the Waste and Hygiene Compartment (WHC) yearly maintenance in the Tranquility node of the International Space Station. The maintenance included removing and replacing the urine hydraulic components which include urine lines, urine valve block and urine pressure sensors, and removing and replacing the Flush Water Tank Pressure Sensor.

Prognostics Methodology for Complex Systems

NASA Technical Reports Server (NTRS)

Gulati, Sandeep; Mackey, Ryan

2003-01-01

An automatic method to schedule maintenance and repair of complex systems is produced based on a computational structure called the Informed Maintenance Grid (IMG). This method provides solutions to the two fundamental problems in autonomic logistics: (1) unambiguous detection of deterioration or impending loss of function and (2) determination of the time remaining to perform maintenance or other corrective action based upon information from the system. The IMG provides a health determination over the medium-to-longterm operation of the system, from one or more days to years of study. The IMG is especially applicable to spacecraft and both piloted and autonomous aircraft, or industrial control processes.

A performance improvement case study in aircraft maintenance and its implications for hazard identification.

PubMed

Ward, Marie; McDonald, Nick; Morrison, Rabea; Gaynor, Des; Nugent, Tony

2010-02-01

Aircraft maintenance is a highly regulated, safety critical, complex and competitive industry. There is a need to develop innovative solutions to address process efficiency without compromising safety and quality. This paper presents the case that in order to improve a highly complex system such as aircraft maintenance, it is necessary to develop a comprehensive and ecologically valid model of the operational system, which represents not just what is meant to happen, but what normally happens. This model then provides the backdrop against which to change or improve the system. A performance report, the Blocker Report, specific to aircraft maintenance and related to the model was developed gathering data on anything that 'blocks' task or check performance. A Blocker Resolution Process was designed to resolve blockers and improve the current check system. Significant results were obtained for the company in the first trial and implications for safety management systems and hazard identification are discussed. Statement of Relevance: Aircraft maintenance is a safety critical, complex, competitive industry with a need to develop innovative solutions to address process and safety efficiency. This research addresses this through the development of a comprehensive and ecologically valid model of the system linked with a performance reporting and resolution system.

Developing RCM Strategy for Hydrogen Fuel Cells Utilizing On Line E-Condition Monitoring

NASA Astrophysics Data System (ADS)

Baglee, D.; Knowles, M. J.

2012-05-01

Fuel cell vehicles are considered to be a viable solution to problems such as carbon emissions and fuel shortages for road transport. Proton Exchange Membrane (PEM) Fuel Cells are mainly used in this purpose because they can run at low temperatures and have a simple structure. Yet high maintenance costs and the inherent dangers of maintaining equipment using hydrogen are two main issues which need to be addressed. The development of appropriate and efficient strategies is currently lacking with regard to fuel cell maintenance. A Reliability Centered Maintenance (RCM) approach offers considerable benefit to the management of fuel cell maintenance since it includes an identification and consideration of the impact of critical components. Technological developments in e-maintenance systems, radio-frequency identification (RFID) and personal digital assistants (PDAs) have proven to satisfy the increasing demand for improved reliability, efficiency and safety. RFID technology is used to store and remotely retrieve electronic maintenance data in order to provide instant access to up-to-date, accurate and detailed information. The aim is to support fuel cell maintenance decisions by developing and applying a blend of leading-edge communications and sensor technology including RFID. The purpose of this paper is to review and present the state of the art in fuel cell condition monitoring and maintenance utilizing RCM and RFID technologies. Using an RCM analysis critical components and fault modes are identified. RFID tags are used to store the critical information, possible faults and their cause and effect. The relationship between causes, faults, symptoms and long term implications of fault conditions are summarized. Finally conclusions are drawn regarding suggested maintenance strategies and the optimal structure for an integrated, cost effective condition monitoring and maintenance management system.

Functional compartmentalization of Rad9 and Hus1 reveals diverse assembly of the 9‐1‐1 complex components during the DNA damage response in Leishmania

PubMed Central

Damasceno, Jeziel D.; Obonaga, Ricardo; Santos, Elaine V.; Scott, Alan; McCulloch, Richard

2016-01-01

Summary The Rad9‐Rad1‐Hus1 (9‐1‐1) complex is a key component in the coordination of DNA damage sensing, cell cycle progression and DNA repair pathways in eukaryotic cells. This PCNA‐related trimer is loaded onto RPA‐coated single stranded DNA and interacts with ATR kinase to mediate effective checkpoint signaling to halt the cell cycle and to promote DNA repair. Beyond these core activities, mounting evidence suggests that a broader range of functions can be provided by 9‐1‐1 structural diversification. The protozoan parasite Leishmania is an early‐branching eukaryote with a remarkably plastic genome, which hints at peculiar genome maintenance mechanisms. Here, we investigated the existence of homologs of the 9‐1‐1 complex subunits in L. major and found that LmRad9 and LmRad1 associate with chromatin in response to replication stress and form a complex in vivo with LmHus1. Similar to LmHus1, LmRad9 participates in telomere homeostasis and in the response to both replication stress and double strand breaks. However, LmRad9 and LmHus1‐deficient cells present markedly opposite phenotypes, which suggest their functional compartmentalization. We show that some of the cellular pool of LmRad9 forms an alternative complex and that some of LmHus1 exists as a monomer. We propose that the diverse assembly of the Leishmania 9‐1‐1 subunits mediates functional compartmentalization, which has a direct impact on the response to genotoxic stress. PMID:27301589

Framework for Structural Online Health Monitoring of Aging and Degradation of Secondary Systems due to some Aspects of Erosion

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

Gribok, Andrei; Patnaik, Sobhan; Williams, Christian

This report describes the current state of research related to critical aspects of erosion and selected aspects of degradation of secondary components in nuclear power plants. The report also proposes a framework for online health monitoring of aging and degradation of secondary components. The framework consists of an integrated multi-sensor modality system which can be used to monitor different piping configurations under different degradation conditions. The report analyses the currently known degradation mechanisms and available predictive models. Based on this analysis, the structural health monitoring framework is proposed. The Light Water Reactor Sustainability Program began to evaluate technologies that couldmore » be used to perform online monitoring of piping and other secondary system structural components in commercial NPPs. These online monitoring systems have the potential to identify when a more detailed inspection is needed using real-time measurements, rather than at a pre-determined inspection interval. This transition to condition-based, risk informed automated maintenance will contribute to a significant reduction of operations and maintenance costs that account for the majority of nuclear power generation costs. There is unanimous agreement between industry experts and academic researchers that identifying and prioritizing inspection locations in secondary piping systems (for example, in raw water piping or diesel piping) would eliminate many excessive in-service inspections. The proposed structural health monitoring framework takes aim at answering this challenge by combining long-range guided wave technologies with other monitoring techniques, which can significantly increase the inspection length and pinpoint the locations that degraded the most. More widely, the report suggests research efforts aimed at developing, validating, and deploying online corrosion monitoring techniques for complex geometries, which are pervasive in NPPs.« less

Automated System Checkout to Support Predictive Maintenance for the Reusable Launch Vehicle

NASA Technical Reports Server (NTRS)

Patterson-Hine, Ann; Deb, Somnath; Kulkarni, Deepak; Wang, Yao; Lau, Sonie (Technical Monitor)

1998-01-01

The Propulsion Checkout and Control System (PCCS) is a predictive maintenance software system. The real-time checkout procedures and diagnostics are designed to detect components that need maintenance based on their condition, rather than using more conventional approaches such as scheduled or reliability centered maintenance. Predictive maintenance can reduce turn-around time and cost and increase safety as compared to conventional maintenance approaches. Real-time sensor validation, limit checking, statistical anomaly detection, and failure prediction based on simulation models are employed. Multi-signal models, useful for testability analysis during system design, are used during the operational phase to detect and isolate degraded or failed components. The TEAMS-RT real-time diagnostic engine was developed to utilize the multi-signal models by Qualtech Systems, Inc. Capability of predicting the maintenance condition was successfully demonstrated with a variety of data, from simulation to actual operation on the Integrated Propulsion Technology Demonstrator (IPTD) at Marshall Space Flight Center (MSFC). Playback of IPTD valve actuations for feature recognition updates identified an otherwise undetectable Main Propulsion System 12 inch prevalve degradation. The algorithms were loaded into the Propulsion Checkout and Control System for further development and are the first known application of predictive Integrated Vehicle Health Management to an operational cryogenic testbed. The software performed successfully in real-time, meeting the required performance goal of 1 second cycle time.

Y-12 Groundwater Protection Program CY2012 Triennial Report Of The Monitoring Well Inspection And Maintenance Program Y-12 National Security Complex, Oak Ridge, Tennessee

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

None

2013-09-01

This document is the triennial report for the Well Inspection and Maintenance Program of the Y- 12 Groundwater Protection Program (GWPP), at the U.S. Department of Energy (DOE) Y-12 National Security Complex (Y-12). This report formally documents well inspections completed by the GWPP on active and inactive wells at Y-12 during calendar years (CY) 2010 through 2012. In addition, this report also documents well inspections performed under the Y-12 Water Resources Restoration Program, which is administered by URS|CH2M Oak Ridge (UCOR). This report documents well maintenance activities completed since the last triennial inspection event (CY 2009); and provides summary tablesmore » of well inspections and well maintenance activities during the reference time period.« less

The Impact of Ground Training on Aviation Readiness

DTIC Science & Technology

2010-04-21

level on the top and bottom of this page. 17. LIMITATION OF ABSTRACT. This block must be completed to assign a distribution limitation to the...have to conduct proficiency training within their specialty. Due to the complex nature of aviation maintenance and operations, a high- level of...Marines must complete. Due to the complex nature of aviation maintenance and operations, a high- level of proficiency must be maintained in order to

AN INVESTIGATION OF THE TRAINING AND SKILL REQUIREMENTS OF INDUSTRIAL MACHINERY MAINTENANCE WORKERS. VOLUME I. FINAL REPORT.

ERIC Educational Resources Information Center

LYNN, FRANK

DRAMATIC CHANGES IN THE CHARACTERISTICS AND COMPLEXITY OF PRODUCTION MACHINERY AND EQUIPMENT HAVE CREATED A GROWING NEED FOR ADEQUATELY TRAINED AND SKILLED MACHINERY MAINTENANCE WORKERS IN INDUSTRY. THIS STUDY DEFINED THE CHARACTERISTICS OF THE LABOR MARKET FOR MACHINERY MAINTENANCE WORKERS SUCH AS MILLWRIGHTS, MECHANICAL HYDRAULIC, ELECTRICAL,…

Approach to In Situ Component Level Electronics Assembly Repair (CLEAR) for Constellation

NASA Technical Reports Server (NTRS)

Struk, Peter M.; Oeftering, Richard C.

2010-01-01

Maintenance resupply is a significant issue for long duration space missions. Currently, the International Space Station (ISS) approaches maintenance primarily around replaceable modules called Orbital Replacement Units (ORU). While swapping out ORUs has served the ISS well keeping crew time for maintenance to a minimum, this approach assumes a substantial logistics capacity to provide replacement ORUs and return ORUs to Earth for repair. The ORUs used for ISS require relatively large blocks of replacement hardware even though the actual failed component may be several orders of magnitude smaller. The Component Level Electronics Assembly Repair (CLEAR) task was created to explore electronics repair down to the component level for future space missions. From 2006 to 2009, CLEAR was an activity under the Supportability project of the Exploration Technology Development Program. This paper describes the activities of CLEAR including making a case for component-level electronics repair, examination of current terrestrial repair hardware, and potential repair needs. Based on those needs, the CLEAR team proposes an architecture for an in-situ repair capability aboard a spacecraft or habitat. Additionally, this paper discusses recent progress toward developing in-space repair capabilities--including two spaceflight experiments-- and presents technology concepts which could help enable or benefit the same.

Aviation Maintenance Technology. Course Content Guides. FAA Approved Curriculum.

ERIC Educational Resources Information Center

Shrawder, Jack; And Others

Course content guides are provided for the 30 courses in this aviation maintenance technology curriculum approved by the Federal Aviation Administration. Course titles are physics for technicians; aircraft information, regulations, and procedures; aircraft assembly; fundamentals of aircraft electronics; aircraft electrical components; aircraft…

40 CFR 1039.125 - What maintenance instructions must I give to buyers?

Code of Federal Regulations, 2011 CFR

2011-07-01

... maintaining and using the engine, including the emission-control system. The maintenance instructions also...,000 hours: Fuel injectors, turbochargers, catalytic converters, electronic control units, EGR systems..., catalytic converters, electronic control units, EGR systems (including related components, but excluding...

40 CFR 1039.125 - What maintenance instructions must I give to buyers?

Code of Federal Regulations, 2012 CFR

2012-07-01

... maintaining and using the engine, including the emission-control system. The maintenance instructions also...,000 hours: Fuel injectors, turbochargers, catalytic converters, electronic control units, EGR systems..., catalytic converters, electronic control units, EGR systems (including related components, but excluding...

40 CFR 1039.125 - What maintenance instructions must I give to buyers?

Code of Federal Regulations, 2013 CFR

2013-07-01

... maintaining and using the engine, including the emission-control system. The maintenance instructions also...,000 hours: Fuel injectors, turbochargers, catalytic converters, electronic control units, EGR systems..., catalytic converters, electronic control units, EGR systems (including related components, but excluding...

40 CFR 1039.125 - What maintenance instructions must I give to buyers?

Code of Federal Regulations, 2014 CFR

2014-07-01

... maintaining and using the engine, including the emission-control system. The maintenance instructions also...,000 hours: Fuel injectors, turbochargers, catalytic converters, electronic control units, EGR systems..., catalytic converters, electronic control units, EGR systems (including related components, but excluding...

10-MWe solar-thermal central-receiver pilot plant. Operating and maintenance manual

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

Not Available

1979-08-01

Information required to perform the initial program loading and operation of the Heliostat Array Controller (HAC) is provided. Operating activities are described as required for heliostat control. All computer console command steps, from power up to power down are described. Detailed steps are provided to wake up the system and direct heliostat beams to standby, on target, standby to stow and power down. Maintenance requirements (preventive and corrective), reparability (reparable - non-reparable decisions), spares identification, spares storage location, replacement levels, replacement location and repair location are established. Individual system breakdown block diagrams are provided for each system/assembly/subassembly. Maintenance and repairmore » description sheets are provided for each maintenance significant item. The manual provides support of the following equipment: (a) helostat assembly; (b) heliostat control assembly; and (c) maintenance and installation equipment. The safety requirements for the operating and maintenance functions are established. These procedures will assist in eliminating or controlling the accident potentials caused by human error, environment, or component malfunctions or interactions that could result in major injury or fatality to operating or visiting personnel, or damage to subsystem components or support equipment. These procedures are for normal and test operating conditions and emergency situations, and apply to all Martin Marietta Corporation, governmental, operating and visitor personnel. (LEW)« less

Planning factors for developing an enterprise-wide picture archiving and communication system maintenance program.

PubMed

Staley, S; Romlein, J; Chacko, A K; Wider, R

2000-05-01

Picture archiving and communication system (PACS) maintenance on an individual site basis has historically been a complex and costly challenge. With the advent of enterprise-wide PACS projects such as the Virtual Radiology Environment (VRE) project, the challenge of a maintenance program with even more complexities has presented itself. The approach of the project management team for the VRE project is not one of reactive maintenance, but one of highly proactive planning and negotiations, in hopes of capitalizing on the economies of scale of an enterprise-wide PACS maintenance program. A proactive maintenance program is one aspect of life-cycle management. As with any capital acquisition, life-cycle management may be used to manage the specific project aspects related to PACS. The purpose of an enterprise-wide warranty and maintenance life-cycle management approach is to maintain PACS at its maximum operational efficiency and utilization levels through a flexible, shared, yet symbiotic relationship between local, regional, and vendor resources. These goals include providing maximum operational performance levels on a local, regional, and enterprise basis, while maintaining acceptable costs and resource utilization levels. This goal must be achieved without negatively impacting point of care activities, regardless of changes to the clinical business environment.

Data system for planning maintenance resurfacing.

DOT National Transportation Integrated Search

1973-01-01

Planning for maintenance resurfacing in the Virginia Department of Highways is becoming an increasingly complex and important function. Increasing highway mileage and traffic volumes, as well as other requirements such as maintaining a minimum skid r...

Genetic Interactions Between the Meiosis-Specific Cohesin Components, STAG3, REC8, and RAD21L.

PubMed

Ward, Ayobami; Hopkins, Jessica; Mckay, Matthew; Murray, Steve; Jordan, Philip W

2016-06-01

Cohesin is an essential structural component of chromosomes that ensures accurate chromosome segregation during mitosis and meiosis. Previous studies have shown that there are cohesin complexes specific to meiosis, required to mediate homologous chromosome pairing, synapsis, recombination, and segregation. Meiosis-specific cohesin complexes consist of two structural maintenance of chromosomes proteins (SMC1α/SMC1β and SMC3), an α-kleisin protein (RAD21, RAD21L, or REC8), and a stromal antigen protein (STAG1, 2, or 3). STAG3 is exclusively expressed during meiosis, and is the predominant STAG protein component of cohesin complexes in primary spermatocytes from mouse, interacting directly with each α-kleisin subunit. REC8 and RAD21L are also meiosis-specific cohesin components. Stag3 mutant spermatocytes arrest in early prophase ("zygotene-like" stage), displaying failed homolog synapsis and persistent DNA damage, as a result of unstable loading of cohesin onto the chromosome axes. Interestingly, Rec8, Rad21L double mutants resulted in an earlier "leptotene-like" arrest, accompanied by complete absence of STAG3 loading. To assess genetic interactions between STAG3 and α-kleisin subunits RAD21L and REC8, our lab generated Stag3, Rad21L, and Stag3, Rec8 double knockout mice, and compared them to the Rec8, Rad21L double mutant. These double mutants are phenotypically distinct from one another, and more severe than each single knockout mutant with regards to chromosome axis formation, cohesin loading, and sister chromatid cohesion. The Stag3, Rad21L, and Stag3, Rec8 double mutants both progress further into prophase I than the Rec8, Rad21L double mutant. Our genetic analysis demonstrates that cohesins containing STAG3 and REC8 are the main complex required for centromeric cohesion, and RAD21L cohesins are required for normal clustering of pericentromeric heterochromatin. Furthermore, the STAG3/REC8 and STAG3/RAD21L cohesins are the primary cohesins required for axis formation. Copyright © 2016 Ward et al.

Transmission overhaul estimates for partial and full replacement at repair

NASA Technical Reports Server (NTRS)

Savage, M.; Lewicki, D. G.

1991-01-01

Timely transmission overhauls increase in-flight service reliability greater than the calculated design reliabilities of the individual aircraft transmission components. Although necessary for aircraft safety, transmission overhauls contribute significantly to aircraft expense. Predictions of a transmission's maintenance needs at the design stage should enable the development of more cost effective and reliable transmissions in the future. The frequency is estimated of overhaul along with the number of transmissions or components needed to support the overhaul schedule. Two methods based on the two parameter Weibull statistical distribution for component life are used to estimate the time between transmission overhauls. These methods predict transmission lives for maintenance schedules which repair the transmission with a complete system replacement or repair only failed components of the transmission. An example illustrates the methods.

Comparison of Spares Logistics Analysis Techniques for Long Duration Human Spaceflight

NASA Technical Reports Server (NTRS)

Owens, Andrew; de Weck, Olivier; Mattfeld, Bryan; Stromgren, Chel; Cirillo, William

2015-01-01

As the durations and distances involved in human exploration missions increase, the logistics associated with the repair and maintenance becomes more challenging. Whereas the operation of the International Space Station (ISS) depends upon regular resupply from the Earth, this paradigm may not be feasible for future missions. Longer mission durations result in higher probabilities of component failures as well as higher uncertainty regarding which components may fail, and longer distances from Earth increase the cost of resupply as well as the speed at which the crew can abort to Earth in the event of an emergency. As such, mission development efforts must take into account the logistics requirements associated with maintenance and spares. Accurate prediction of the spare parts demand for a given mission plan and how that demand changes as a result of changes to the system architecture enables full consideration of the lifecycle cost associated with different options. In this paper, we utilize a range of analysis techniques - Monte Carlo, semi-Markov, binomial, and heuristic - to examine the relationship between the mass of spares and probability of loss of function related to the Carbon Dioxide Removal System (CRS) for a notional, simplified mission profile. The Exploration Maintainability Analysis Tool (EMAT), developed at NASA Langley Research Center, is utilized for the Monte Carlo analysis. We discuss the implications of these results and the features and drawbacks of each method. In particular, we identify the limitations of heuristic methods for logistics analysis, and the additional insights provided by more in-depth techniques. We discuss the potential impact of system complexity on each technique, as well as their respective abilities to examine dynamic events. This work is the first step in an effort that will quantitatively examine how well these techniques handle increasingly more complex systems by gradually expanding the system boundary.

H3K9me3 demethylase Kdm4d facilitates the formation of pre-initiative complex and regulates DNA replication.

PubMed

Wu, Rentian; Wang, Zhiquan; Zhang, Honglian; Gan, Haiyun; Zhang, Zhiguo

2017-01-09

DNA replication is tightly regulated to occur once and only once per cell cycle. How chromatin, the physiological substrate of DNA replication machinery, regulates DNA replication remains largely unknown. Here we show that histone H3 lysine 9 demethylase Kdm4d regulates DNA replication in eukaryotic cells. Depletion of Kdm4d results in defects in DNA replication, which can be rescued by the expression of H3K9M, a histone H3 mutant transgene that reverses the effect of Kdm4d on H3K9 methylation. Kdm4d interacts with replication proteins, and its recruitment to DNA replication origins depends on the two pre-replicative complex components (origin recognition complex [ORC] and minichromosome maintenance [MCM] complex). Depletion of Kdm4d impairs the recruitment of Cdc45, proliferating cell nuclear antigen (PCNA), and polymerase δ, but not ORC and MCM proteins. These results demonstrate a novel mechanism by which Kdm4d regulates DNA replication by reducing the H3K9me3 level to facilitate formation of pre-initiative complex. © The Author(s) 2016. Published by Oxford University Press on behalf of Nucleic Acids Research.

Advanced Ground Systems Maintenance Prognostics Project

NASA Technical Reports Server (NTRS)

Perotti, Jose M.

2015-01-01

The project implements prognostics capabilities to predict when a component system or subsystem will no longer meet desired functional or performance criteria, called the end of life. The capability also provides an assessment of the remaining useful life of a hardware component. The project enables the delivery of system health advisories to ground system operators. This project will use modeling techniques and algorithms to assess components' health andpredict remaining life for such components. The prognostics capability being developed will beused:during the design phase and during pre/post operations to conduct planning and analysis ofsystem design, maintenance & logistics plans, and system/mission operations plansduring real-time operations to monitor changes to components' health and assess their impacton operations.This capability will be interfaced to Ground Operations' command and control system as a part ofthe AGSM project to help assure system availability and mission success. The initial modelingeffort for this capability will be developed for Liquid Oxygen ground loading applications.

SCADA alarms processing for wind turbine component failure detection

NASA Astrophysics Data System (ADS)

Gonzalez, E.; Reder, M.; Melero, J. J.

2016-09-01

Wind turbine failure and downtime can often compromise the profitability of a wind farm due to their high impact on the operation and maintenance (O&M) costs. Early detection of failures can facilitate the changeover from corrective maintenance towards a predictive approach. This paper presents a cost-effective methodology to combine various alarm analysis techniques, using data from the Supervisory Control and Data Acquisition (SCADA) system, in order to detect component failures. The approach categorises the alarms according to a reviewed taxonomy, turning overwhelming data into valuable information to assess component status. Then, different alarms analysis techniques are applied for two purposes: the evaluation of the SCADA alarm system capability to detect failures, and the investigation of the relation between components faults being followed by failure occurrences in others. Various case studies are presented and discussed. The study highlights the relationship between faulty behaviour in different components and between failures and adverse environmental conditions.

Cancer incidence and mortality among temporary maintenance workers in a refinery/petrochemical complex in Korea

PubMed Central

Koh, Dong-Hee; Chung, Eun-Kyo; Jang, Jae-Kil; Lee, Hye-Eun; Ryu, Hyang-Woo; Yoo, Kye-Mook; Kim, Eun-A; Kim, Kyoo-Sang

2014-01-01

Background: Petrochemical plant maintenance workers are exposed to various carcinogens such as benzene and metal fumes. In Korea, maintenance operations in petrochemical plants are typically performed by temporary employees hired as contract workers. Objectives: The purpose of this retrospective study was to evaluate cancer risk in temporary maintenance workers in a refinery/petrochemical complex in Korea. Methods: Subjects consisted of 14 698 male workers registered in a regional petrochemical plant maintenance workers union during 2002–2007. Cancer mortality and incidence were identified by linking with the nationwide death and cancer registries during 2002–2007 and 2002–2005, respectively. Standardized mortality ratios (SMRs) and standardized incidence ratios (SIRs) were calculated for each cancer. Results: Increased SMR 3.61 (six cases, 95% CI: 1.32–7.87) and SIR 3.18 (five cases, 95% CI: 1.03–7.42) were observed in oral and pharyngeal cancers. Conclusion: Our findings may suggest a potential association between oral and pharyngeal cancers and temporary maintenance jobs in the petrochemical industry. Future studies should include a longer follow-up period and a quantitative exposure assessment. PMID:24999849

A Homeowner's Guide to Septic Systems.

ERIC Educational Resources Information Center

Sponenberg, Torsten D.; And Others

This booklet provides basic information on septic system use and maintenance. Written for current and prospective homeowners, it offers guidelines for proper operation of household septic systems. In addition, (1) components of individual systems are diagrammatically explained; (2) suggestions for maintenance are outlined; (3) problem areas and…

Diesel Vehicle Maintenance Competencies.

ERIC Educational Resources Information Center

Braswell, Robert; And Others

Designed to provide a model set of competencies, this manual presents tasks which were identified by employers, employees, and teachers as important in a postsecondary diesel vehicle maintenance curriculum. The tasks are divided into seven major component areas of instruction: chassis and suspension, diesel engines, diesel fuel, electrical,…

49 CFR 238.503 - Inspection, testing, and maintenance requirements.

Code of Federal Regulations, 2010 CFR

2010-10-01

... inspection, testing, or maintenance task under this part. (i) Standard procedures. The program under paragraph (a) of this section shall include the railroad's written standard procedures for performing all... this section shall contain the railroad's written procedures to ensure that all systems and components...

DOE handbook: Guide to good practices for training and qualification of maintenance personnel

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

NONE

1996-03-01

The purpose of this Handbook is to provide contractor training organizations with information that can be used to verify the adequacy of and/or modify existing maintenance training programs, or to develop new training programs. This guide, used in conjunction with facility-specific job analyses, provides a framework for training and qualification programs for maintenance personnel at DOE reactor and nonreactor nuclear facilities. Recommendations for qualification are made in four areas: education, experience, physical attributes, and training. The functional positions of maintenance mechanic, electrician, and instrumentation and control technician are covered by this guide. Sufficient common knowledge and skills were found tomore » include the three disciplines in one guide to good practices. Contents include: qualifications; on-the-job training; trainee evaluation; continuing training; training effectiveness evaluation; and program records. Appendices are included which relate to: administrative training; industrial safety training; fundamentals training; tools and equipment training; facility systems and component knowledge training; facility systems and component skills training; and specialized skills training.« less

Browns Ferry turbine team-it`s all in the planning

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

NONE

1995-05-01

This article illustrates a good example of how a project was creatively completed ahead of schedule and under budget. When the Brown`s Ferry turbine maintenance team took on the task of servicing unit 2`s turbine, the work was like building a ship in a bottle. {open_quotes}We had no room in which to work and only standard tools for the maintenance{close_quotes}, said Jim Roche, turbine manager. The big problem on the turbine floor is that there is only one single overhead crane for lifting the turbine components. All the major turbine components and support equipment are on the same floor. Eachmore » one requires a crane, and there is only one crane. There is limited laydown space. To do the maintenance properly, the team had to have a maintenance schedule it felt comfortable with, industry experience, tools yet to be invented, and money. The design method for this schedule is presented.« less

Low-Cost Oil Quality Sensor Based on Changes in Complex Permittivity

PubMed Central

Pérez, Angel Torres; Hadfield, Mark

2011-01-01

Real time oil quality monitoring techniques help to protect important industry assets, minimize downtime and reduce maintenance costs. The measurement of a lubricant’s complex permittivity is an effective indicator of the oil degradation process and it can be useful in condition based maintenance (CBM) to select the most adequate oil replacement maintenance schedules. A discussion of the working principles of an oil quality sensor based on a marginal oscillator to monitor the losses of the dielectric at high frequencies (>1 MHz) is presented. An electronic design procedure is covered which results in a low cost, effective and ruggedized sensor implementation suitable for use in harsh environments. PMID:22346666

Reusable rocket engine turbopump condition monitoring

NASA Technical Reports Server (NTRS)

Hampson, M. E.; Barkhoudarian, S.

1985-01-01

Significant improvements in engine readiness with attendant reductions in maintenance costs and turnaround times can be achieved with an engine condition monitoring system (CMS). The CMS provides real time health status of critical engine components, without disassembly, through component monitoring with advanced sensor technologies. Three technologies were selected to monitor the rotor bearings and turbine blades: the isotope wear detector and fiber optic deflectometer (bearings), and the fiber optic pyrometer (blades). Signal processing algorithms were evaluated and ranked for their utility in providing useful component health data to unskilled maintenance personnel. Design modifications to current configuration Space Shuttle Main Engine (SSME) high pressure turbopumps and the MK48-F turbopump were developed to incorporate the sensors.

Organizational justice and insomnia: Relationships between justice components and insomnia symptoms among private company workers in Japan.

PubMed

Hayashi, Toshio; Odagiri, Yuko; Takamiya, Tomoko; Ohya, Yumiko; Inoue, Shigeru

2015-01-01

Organizational justice (OJ) is an important psychosocial factor and it consists of several components. Previous studies have shown that low perceived OJ is associated with various health problems. However, the relationships between each justice component and health outcomes have not been fully examined. The purpose of this study was to clarify the relationships between OJ and insomnia, including OJ components and insomnia symptoms. Cross-sectional self-reported questionnaire data from 1,893 employees (92.2% of subjects) were collected. OJ was measured using the Japanese version of the OJ questionnaire, which has four components (distributive, procedural, interpersonal and informational). Insomnia was assessed with the Athens Insomnia Scale. Logistic regression analysis, with insomnia as a dependent variable and OJ as an independent variable, was conducted. Subjects with low overall OJ had a higher risk of insomnia (adjusted odds ratio (AOR), 2.37; 95% confidence interval (CI), 1.59 to 3.53) and two insomnia symptoms (AOR of 2.47 and 95% CI of 1.68 to 3.65 for sleep induction problem; AOR of 1.73 and 95% CI of 1.21 to 2.48 for sleep maintenance problem). The four justice components were all associated with insomnia and sleep induction problems. Sleep maintenance problems were associated with only the distributive justice component. All four justice components were associated with both insomnia and sleep induction problems. Sleep maintenance problems, however, showed different features. Specifically, the distributive justice component seemed to be a key factor in the relationship between OJ and insomnia. These findings might provide useful information for preventing the adverse effects of insomnia.

The precision segmented reflectors: Moderate mission figure control subsystem

NASA Technical Reports Server (NTRS)

Sevaston, G.; Redding, D.; Lau, K.; Breckenridge, W.; Levine, B.; Nerheim, N.; Sirlin, S.; Kadogawa, H.

1991-01-01

A system concept for a space based segmented reflector telescope figure control subsystem is described. The concept employs a two phase architecture in which figure initialization and figure maintenance are independent functions. Figure initialization is accomplished by image sharpening using natural reference targets. Figure maintenance is performed by monitoring the relative positions and alignments of the telescope components using an optical truss. Actuation is achieved using precision positioners. Computer simulation results of figure initialization by pairwise segment coalignment/cophasing and simulated annealing are presented along with figure maintenance results using a wavefront error regulation algorithm. Both functions are shown to perform at acceptable levels for the class of submillimeter telescopes that are serving as the focus of this technology development effort. Component breadboard work as well as plans for a system testbed are discussed.

Orbit Transfer Rocket Engine Technology Program: Advanced engine study, task D.1/D.3

NASA Technical Reports Server (NTRS)

Martinez, A.; Erickson, C.; Hines, B.

1986-01-01

Concepts for space maintainability of OTV engines were examined. An engine design was developed which was driven by space maintenance requirements and by a failure mode and effects (FME) analysis. Modularity within the engine was shown to offer cost benefits and improved space maintenance capabilities. Space operable disconnects were conceptualized for both engine change-out and for module replacement. Through FME mitigation the modules were conceptualized to contain the least reliable and most often replaced engine components. A preliminary space maintenance plan was developed around a controls and condition monitoring system using advanced sensors, controls, and condition monitoring concepts. A complete engine layout was prepared satisfying current vehicle requirements and utilizing projected component advanced technologies. A technology plan for developing the required technology was assembled.

Local and systemic toxicity of JP-8 from cutaneous exposures.

PubMed

McDougal, James N; Rogers, James V

2004-04-01

Jet propellant-8 (JP-8) jet fuel is a version of commercial jet fuel, Jet A, and is a complex mixture of primarily aliphatic (but also aromatic) hydrocarbons that varies in composition from batch to batch. There is potential for dermal exposure to jet fuels with personnel involved in aircraft refueling and maintenance operations as well as ground personnel. Cutaneous exposures have the potential to cause skin irritation, sensitization or skin cancer. JP-8 has been shown to be irritating and causes molecular changes in the skin of laboratory animals. The mechanisms of some of these effects have been investigated in intact skin and cultured skin cells. Hydrocarbons have also been shown to cause skin cancer with repeated application to the skin. Additionally, there is concern about systemic toxicity from dermal exposures to jet fuels, such as JP-8. Assessing risks from systemic absorption of hydrocarbon components is complex because most of the components are present in the mixture in small quantities (less than 1%). The effect of the fuel as a vehicle, different rates of penetration through the skin and different target organ toxicities all complicate the assessment of the hazards of cutaneous exposures. The purpose of this manuscript is to review studies of local and systemic toxicity of JP-8.

Software Intensive Systems Data Quality and Estimation Research in Support of Future Defense Cost Analysis

DTIC Science & Technology

2012-03-13

Legacy Maintenance and Brownfield Development 6.6.6 Agile and Kanban Development 6.6.7 Putting It All Together at the Large-Project or Enterprise Level...NDI)-intensive systems Ultrahigh software system assurance; Legacy maintenance and brownfield development; and Agile and kanban development. This...be furnished by NDI components or may need to be developed for special systems. Legacy Maintenance and Brownfield Development Fewer and fewer software

AUTOMOTIVE DIESEL MAINTENANCE 1. UNIT XXV, I--CATERPILLAR DIESEL ENGINE COOLING SYSTEM D-8 AND 824 MODELS, II--TIRES AND TIRE HARDWARE.

ERIC Educational Resources Information Center

Minnesota State Dept. of Education, St. Paul. Div. of Vocational and Technical Education.

THIS MODULE OF A 30-MODULE COURSE IS DESIGNED TO DEVELOP AN UNDERSTANDING OF THE OPERATION AND MAINTENANCE OF THE DIESEL ENGINE COOLING SYSTEM AND TO PROVIDE A DESCRIPTION OF HEAVY TIRES AND WHEELS USED ON DIESEL POWERED VEHICLES. TOPICS ARE (1) THEORY OF THE COOLING SYSTEM, (2) COOLING SYSTEM COMPONENTS, (3) MAINTENANCE TIPS (COOLING SYSTEM), (4)…

Maternal dazap2 Regulates Germ Granules by Counteracting Dynein in Zebrafish Primordial Germ Cells.

PubMed

Forbes, Meredyth M; Rothhämel, Sophie; Jenny, Andreas; Marlow, Florence L

2015-07-07

Primordial germ cells (PGCs) are the stem cells of the germline. Generally, germline induction occurs via zygotic factors or the inheritance of maternal determinants called germ plasm (GP). GP is packaged into ribonucleoprotein complexes within oocytes and later promotes the germline fate in embryos. Once PGCs are specified by either mechanism, GP components localize to perinuclear granular-like structures. Although components of zebrafish PGC germ granules have been studied, the maternal factors regulating their assembly and contribution to germ cell development are unknown. Here, we show that the scaffold protein Dazap2 binds to Bucky ball, an essential regulator of oocyte polarity and GP assembly, and colocalizes with the GP in oocytes and in PGCs. Mutational analysis revealed a requirement for maternal Dazap2 (MDazap2) in germ-granule maintenance. Through molecular epistasis analyses, we show that MDazap2 is epistatic to Tdrd7 and maintains germ granules in the embryonic germline by counteracting Dynein activity. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

Zim17/Tim15 links mitochondrial iron-sulfur cluster biosynthesis to nuclear genome stability.

PubMed

Díaz de la Loza, María Del Carmen; Gallardo, Mercedes; García-Rubio, María Luisa; Izquierdo, Alicia; Herrero, Enrique; Aguilera, Andrés; Wellinger, Ralf Erik

2011-08-01

Genomic instability is related to a wide-range of human diseases. Here, we show that mitochondrial iron-sulfur cluster biosynthesis is important for the maintenance of nuclear genome stability in Saccharomyces cerevisiae. Cells lacking the mitochondrial chaperone Zim17 (Tim15/Hep1), a component of the iron-sulfur biosynthesis machinery, have limited respiration activity, mimic the metabolic response to iron starvation and suffer a dramatic increase in nuclear genome recombination. Increased oxidative damage or deficient DNA repair do not account for the observed genomic hyperrecombination. Impaired cell-cycle progression and genetic interactions of ZIM17 with components of the RFC-like complex involved in mitotic checkpoints indicate that replicative stress causes hyperrecombination in zim17Δ mutants. Furthermore, nuclear accumulation of pre-ribosomal particles in zim17Δ mutants reinforces the importance of iron-sulfur clusters in normal ribosome biosynthesis. We propose that compromised ribosome biosynthesis and cell-cycle progression are interconnected, together contributing to replicative stress and nuclear genome instability in zim17Δ mutants.

Exploiting the Gastric Epithelial Barrier: Helicobacter pylori's Attack on Tight and Adherens Junctions.

PubMed

Backert, Steffen; Schmidt, Thomas P; Harrer, Aileen; Wessler, Silja

2017-01-01

Highly organized intercellular tight and adherens junctions are crucial structural components for establishing and maintenance of epithelial barrier functions, which control the microbiota and protect against intruding pathogens in humans. Alterations in these complexes represent key events in the development and progression of multiple infectious diseases as well as various cancers. The gastric pathogen Helicobacter pylori exerts an amazing set of strategies to manipulate these epithelial cell-to-cell junctions, which are implicated in changing cell polarity, migration and invasive growth as well as pro-inflammatory and proliferative responses. This chapter focuses on the H. pylori pathogenicity factors VacA, CagA, HtrA and urease, and how they can induce host cell signaling involved in altering cell-to-cell permeability. We propose a stepwise model for how H. pylori targets components of tight and adherens junctions in order to disrupt the gastric epithelial cell layer, giving fresh insights into the pathogenesis of this important bacterium.

22 CFR 126.18 - Exemptions regarding intra-company, intra-organization, and intra-governmental transfers to...

Code of Federal Regulations, 2014 CFR

2014-04-01

... to such countries, maintenance of business relationships with persons from such countries, maintenance of a residence in such countries, receiving salary or other continuing monetary compensation from... by superconducting windings, provided those windings are the only superconducting component in the...

Development of standardized component\\0x2010based equipment specifications and transition plan into a predictive maintenance strategy.

DOT National Transportation Integrated Search

2015-12-01

This project investigated INDOT equipment records and equipment industry standards to produce standard equipment specifications : and a predictive maintenance schedule for the more than 1100 single and tandem axle trucks in use at INDOT. The research...

40 CFR 86.429-78 - Maintenance, unscheduled; test vehicles.

Code of Federal Regulations, 2010 CFR

2010-07-01

... advance approval of the Administrator. (1) In the case of unscheduled maintenance, such approval will be... provisions of this section. (d) Equipment, instruments, or tools may not be used to identify malfunctioning, maladjusted, or defective engine components unless the same or equivalent equipment, instruments, or tools...

Complex analysis of energy efficiency in operated high-rise residential building: Case study

NASA Astrophysics Data System (ADS)

Korniyenko, Sergey

2018-03-01

Energy conservation and human thermal comfort enhancement in buildings is a topical issue of modern architecture and construction. The innovative solution of this problem makes it possible to enhance building ecological and maintenance safety, to reduce hydrocarbon fuel consumption, and to improve life standard of people. The requirements to increase of energy efficiency in buildings should be provided at all the stages of building's life cycle that is at the stage of design, construction and maintenance of buildings. The research purpose is complex analysis of energy efficiency in operated high-rise residential building. Many actions for building energy efficiency are realized according to the project; mainly it is the effective building envelope and engineering systems. Based on results of measurements the energy indicators of the building during annual period have been calculated. The main reason of increase in heat losses consists in the raised infiltration of external air in the building through a building envelope owing to the increased air permeability of windows and balcony doors (construction defects). Thermorenovation of the building based on ventilating and infiltration heat losses reduction through a building envelope allows reducing annual energy consumption. Energy efficiency assessment based on the total annual energy consumption of building, including energy indices for heating and a ventilation, hot water supply and electricity supply, in comparison with heating is more complete. The account of various components in building energy balance completely corresponds to modern direction of researches on energy conservation and thermal comfort enhancement in buildings.

Relations between Short-term Memory Deficits, Semantic Processing, and Executive Function

PubMed Central

Allen, Corinne M.; Martin, Randi C.; Martin, Nadine

2012-01-01

Background Previous research has suggested separable short-term memory (STM) buffers for the maintenance of phonological and lexical-semantic information, as some patients with aphasia show better ability to retain semantic than phonological information and others show the reverse. Recently, researchers have proposed that deficits to the maintenance of semantic information in STM are related to executive control abilities. Aims The present study investigated the relationship of executive function abilities with semantic and phonological short-term memory (STM) and semantic processing in such patients, as some previous research has suggested that semantic STM deficits and semantic processing abilities are critically related to specific or general executive function deficits. Method and Procedures 20 patients with aphasia and STM deficits were tested on measures of short-term retention, semantic processing, and both complex and simple executive function tasks. Outcome and Results In correlational analyses, we found no relation between semantic STM and performance on simple or complex executive function tasks. In contrast, phonological STM was related to executive function performance in tasks that had a verbal component, suggesting that performance in some executive function tasks depends on maintaining or rehearsing phonological codes. Although semantic STM was not related to executive function ability, performance on semantic processing tasks was related to executive function, perhaps due to similar executive task requirements in both semantic processing and executive function tasks. Conclusions Implications for treatment and interpretations of executive deficits are discussed. PMID:22736889

Progress toward an advanced condition monitoring system for reusable rocket engines

NASA Technical Reports Server (NTRS)

Maram, J.; Barkhoudarian, S.

1987-01-01

A new generation of advanced sensor technologies will allow the direct measurement of critical/degradable rocket engine components' health and the detection of degraded conditions before component deterioration affects engine performance, leading to substantial improvements in reusable engines' operation and maintenance. When combined with a computer-based engine condition-monitoring system, these sensors can furnish a continuously updated data base for the prediction of engine availability and advanced warning of emergent maintenance requirements. Attention is given to the case of a practical turbopump and combustion device diagnostic/prognostic health-monitoring system.

Emotion and working memory: evidence for domain-specific processes for affective maintenance.

PubMed

Mikels, Joseph A; Reuter-Lorenz, Patricia A; Beyer, Jonathan A; Fredrickson, Barbara L

2008-04-01

Working memory is comprised of separable subsystems for visual and verbal information, but what if the information is affective? Does the maintenance of affective information rely on the same processes that maintain nonaffective information? The authors address this question using a novel delayed-response task developed to investigate the short-term maintenance of affective memoranda. Using selective interference methods the authors find that a secondary emotion-regulation task impaired affect intensity maintenance, whereas secondary cognitive tasks disrupted brightness intensity maintenance, but facilitated affect maintenance. Additionally, performance on the affect maintenance task depends on the valence of the maintained feeling, further supporting the domain-specific nature of the task. The importance of affect maintenance per se is further supported by demonstrating that the observed valence effects depend on a memory delay and are not evident with simultaneous presentation of stimuli. These findings suggest that the working memory system may include domain-specific components that are specialized for the maintenance of affective memoranda. (Copyright) 2008 APA.

The human CTC1/STN1/TEN1 complex regulates telomere maintenance in ALT cancer cells

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

Huang, Chenhui; Jia, Pingping; Chastain, Megan

Maintaining functional telomeres is important for long-term proliferation of cells. About 15% of cancer cells are telomerase-negative and activate the alternative-lengthening of telomeres (ALT) pathway to maintain their telomeres. Recent studies have shown that the human CTC1/STN1/TEN1 complex (CST) plays a multi-faceted role in telomere maintenance in telomerase-expressing cancer cells. However, the role of CST in telomere maintenance in ALT cells is unclear. Here, we report that human CST forms a functional complex localizing in the ALT-associated PML bodies (APBs) in ALT cells throughout the cell cycle. Suppression of CST induces telomere instabilities including telomere fragility and elevates telomeric DNAmore » recombination, leading to telomere dysfunction. In addition, CST deficiency significantly diminishes the abundance of extrachromosomal circular telomere DNA known as C-circles and t-circles. Suppression of CST also results in multinucleation in ALT cells and impairs cell proliferation. Our findings imply that the CST complex plays an important role in regulating telomere maintenance in ALT cells. - Highlights: • CST localizes at telomeres and ALT-associated PML bodies in ALT cells throughout the cell cycle. • CST is important for promoting telomeric DNA replication in ALT cells. • CST deficiency decreases ECTR formation and increases T-SCE. • CST deficiency impairs ALT cell proliferation and results in multinucleation.« less

Mitochondrial phenotype during torpor: Modulation of mitochondrial electron transport system in the Chilean mouse-opossum Thylamys elegans.

PubMed

Cortes, Pablo A; Bozinovic, Francisco; Blier, Pierre U

2018-07-01

Mammalian torpor is a phenotype characterized by a controlled decline of metabolic rate, generally followed by a reduction in body temperature. During arousal from torpor, both metabolic rate and body temperature rapidly returns to resting levels. Metabolic rate reduction experienced by torpid animals is triggered by active suppression of mitochondrial respiration, which is rapidly reversed during rewarming process. In this study, we analyzed the changes in the maximal activity of key enzymes related to electron transport system (complexes I, III and IV) in six tissues of torpid, arousing and euthermic Chilean mouse-opossums (Thylamys elegans). We observed higher maximal activities of complexes I and IV during torpor in brain, heart and liver, the most metabolically active organs in mammals. On the contrary, higher enzymatic activities of complexes III were observed during torpor in kidneys and lungs. Moreover, skeletal muscle was the only tissue without significant differences among stages in all complexes evaluated, suggesting no modulation of oxidative capacities of electron transport system components in this thermogenic tissue. In overall, our data suggest that complexes I and IV activity plays a major role in initiation and maintenance of metabolic suppression during torpor in Chilean mouse-opossum, whereas improvement of oxidative capacities in complex III might be critical to sustain metabolic machinery in organs that remains metabolically active during torpor. Copyright © 2018 Elsevier Inc. All rights reserved.

Function of Brg1 Chromatin Remodeling Factor in Sonic Hedgehog-Dependent Medulloblastoma Initiation and Maintenance

DTIC Science & Technology

2014-10-01

Remodeling Factor in Sonic Hedgehog -Dependent Medulloblastoma Initiation and Maintenance PRINCIPAL INVESTIGATOR: Xuanming Shi CONTRACTING...Function of Brg1 Chromatin Remodeling Factor in Sonic Hedgehog -Dependent 5b. GRANT NUMBER W81XWH-12-1-0527 Medulloblastoma Initiation and Maintenance...medulloblastoma. 15. SUBJECT TERMS Medulloblastoma, Sonic Hedgehog , Chromatin remodeling, BAF complex, Brg1, mouse model of shh-subtype medulloblastoma

Coordination of flower development by homeotic master regulators.

PubMed

Ito, Toshiro

2011-02-01

Floral homeotic genes encode transcription factors and act as master regulators of flower development. The homeotic protein complex is expressed in a specific whorl of the floral primordium and determines floral organ identity by the combinatorial action. Homeotic proteins continue to be expressed until late in flower development to coordinate growth and organogenesis. Recent genomic studies have shown that homeotic proteins bind thousands of target sites in the genome and regulate the expression of transcription factors, chromatin components and various proteins involved in hormone biosynthesis and signaling and other physiological activities. Further, homeotic proteins program chromatin to direct the developmental coordination of stem cell maintenance and differentiation in shaping floral organs. Copyright © 2010 Elsevier Ltd. All rights reserved.

Critical issues in assuring long lifetime and fail-safe operation of optical communications network

NASA Astrophysics Data System (ADS)

Paul, Dilip K.

1993-09-01

Major factors in assuring long lifetime and fail-safe operation in optical communications networks are reviewed in this paper. Reliable functionality to design specifications, complexity of implementation, and cost are the most critical issues. As economics is the driving force to set the goals as well as priorities for the design, development, safe operation, and maintenance schedules of reliable networks, a balance is sought between the degree of reliability enhancement, cost, and acceptable outage of services. Protecting both the link and the network with high reliability components, hardware duplication, and diversity routing can ensure the best network availability. Case examples include both fiber optic and lasercom systems. Also, the state-of-the-art reliability of photonics in space environment is presented.

Cytosine methylation inhibits replication of African cassava mosaic virus by two distinct mechanisms.

PubMed Central

Ermak, G; Paszkowski, U; Wohlmuth, M; Scheid, O M; Paszkowski, J

1993-01-01

Extrachromosomally replicating viral DNA is usually free of cytosine methylation and viral templates methylated in vitro are poor substrates when used in replication assays. We have investigated the mechanism of inhibition of viral replication by DNA methylation using as a model the DNA A of African cassava mosaic virus. We have constructed two component helper systems which allow for separation of the transcriptional inhibition of viral genes necessary for replication from replication inhibition due to altered interaction between the replication complex and methylated viral DNA. Our results suggest that methylation-mediated reduction of viral replication is due to both repression mechanisms and that this provides two independent selection pressures for the maintenance of methylation-free replicons in infected cells. Images PMID:7688453

Replication Fork Protection Factors Controlling R-Loop Bypass and Suppression.

PubMed

Chang, Emily Yun-Chia; Stirling, Peter C

2017-01-14

Replication-transcription conflicts have been a well-studied source of genome instability for many years and have frequently been linked to defects in RNA processing. However, recent characterization of replication fork-associated proteins has revealed that defects in fork protection can directly or indirectly stabilize R-loop structures in the genome and promote transcription-replication conflicts that lead to genome instability. Defects in essential DNA replication-associated activities like topoisomerase, or the minichromosome maintenance (MCM) helicase complex, as well as fork-associated protection factors like the Fanconi anemia pathway, both appear to mitigate transcription-replication conflicts. Here, we will highlight recent advances that support the concept that normal and robust replisome function itself is a key component of mitigating R-loop coupled genome instability.

Transportable Applications Environment (TAE) Plus - A NASA productivity tool used to develop graphical user interfaces

NASA Technical Reports Server (NTRS)

Szczur, Martha R.

1991-01-01

The Transportable Applications Environment (TAE) Plus, developed at NASA's Goddard Space Flight Center, is an advanced portable user interface development environment which simplifies the process of creating and managing complex application graphical user interfaces (GUIs), supports prototyping, allows applications to be oported easily between different platforms, and encourages appropriate levels of user interface consistency between applications. This paper discusses the capabilities of the TAE Plus tool, and how it makes the job of designing and developing GUIs easier for the application developers. The paper also explains how tools like TAE Plus provide for reusability and ensure reliability of UI software components, as well as how they aid in the reduction of development and maintenance costs.

NMESys: An expert system for network fault detection

NASA Technical Reports Server (NTRS)

Nelson, Peter C.; Warpinski, Janet

1991-01-01

The problem of network management is becoming an increasingly difficult and challenging task. It is very common today to find heterogeneous networks consisting of many different types of computers, operating systems, and protocols. The complexity of implementing a network with this many components is difficult enough, while the maintenance of such a network is an even larger problem. A prototype network management expert system, NMESys, implemented in the C Language Integrated Production System (CLIPS). NMESys concentrates on solving some of the critical problems encountered in managing a large network. The major goal of NMESys is to provide a network operator with an expert system tool to quickly and accurately detect hard failures, potential failures, and to minimize or eliminate user down time in a large network.

Determinants of Heart Failure Self-Care Maintenance and Management in Patients and Caregivers: A Dyadic Analysis

PubMed Central

Bidwell, Julie T.; Vellone, Ercole; Lyons, Karen S.; D’Agostino, Fabio; Riegel, Barbara; Vela, Raúl Juárez; Hiatt, Shirin O.; Alvaro, Rosaria; Lee, Christopher S.

2015-01-01

Disease self-management is a critical component of maintaining clinical stability for patients with chronic illness. This is particularly evident in the context of heart failure (HF), which is the leading cause of hospitalization for older adults. HF self- management, commonly known as HF self-care, is often performed with the support of informal caregivers. However, little is known about how HF dyads manage the patient’s care together. The purpose of this study was to identify determinants of patient and caregiver contributions to HF self-care maintenance (i.e., daily adherence and symptom monitoring) and management (i.e., appropriate recognition & response to symptoms), utilizing an approach that controls for dyadic interdependence. This was a secondary analysis of cross-sectional data from 364 Italian HF patients and caregivers. Multilevel modeling was used to identify determinants of HF self-care within patient-caregiver dyads. Patients were 76.2 (SD=10.7) years, a slight majority (56.9%) was male, while caregivers were 57.4 (SD=14.6) years, and fewer than half (48.1%) were male. Most caregivers were adult children (48.4%) or spouses (32.7%) of patients. Both patients and caregivers reported low levels of HF maintenance and management behaviors. Several significant individual and dyadic determinants of self-care maintenance and self-care management were identified, including gender, quality of life, comorbid burden, impaired ADLs, cognition, hospitalizations, HF duration, relationship type, relationship quality, and social support. These comprehensive dyadic models assist in elucidating the complex nature of patient-caregiver relationships and their influence on HF self-care, leading to more effective ways to intervene and maximize outcomes. PMID:26355702

Determinants of Heart Failure Self-Care Maintenance and Management in Patients and Caregivers: A Dyadic Analysis.

PubMed

Bidwell, Julie T; Vellone, Ercole; Lyons, Karen S; D'Agostino, Fabio; Riegel, Barbara; Juárez-Vela, Raúl; Hiatt, Shirin O; Alvaro, Rosaria; Lee, Christopher S

2015-10-01

Disease self-management is a critical component of maintaining clinical stability for patients with chronic illness. This is particularly evident in the context of heart failure (HF), which is the leading cause of hospitalization for older adults. HF self-management, commonly known as HF self-care, is often performed with the support of informal caregivers. However, little is known about how a HF dyad manages the patient's care together. The purpose of this study was to identify determinants of patient and caregiver contributions to HF self-care maintenance (daily adherence and symptom monitoring) and management (appropriate recognition and response to symptoms), utilizing an approach that controls for dyadic interdependence. This was a secondary analysis of cross-sectional data from 364 dyads of Italian HF patients and caregivers. Multilevel modeling was used to identify determinants of HF self-care within patient-caregiver dyads. Patients averaged 76.2 (SD = 10.7) years old, and a slight majority (56.9%) was male, whereas caregivers averaged 57.4 (SD = 14.6) years old, and about half (48.1%) were male. Most caregivers were adult children (48.4%) or spouses (32.7%) of patients. Both patients and caregivers reported low levels of HF maintenance and management behaviors. Significant individual and dyadic determinants of self-care maintenance and self-care management included gender, quality of life, comorbid burden, impaired ADLs, cognition, hospitalizations, HF duration, relationship type, relationship quality, and social support. These comprehensive dyadic models assist in elucidating the complex nature of patient-caregiver relationships and their influence on HF self-care, leading to more effective ways to intervene and optimize outcomes. © 2015 Wiley Periodicals, Inc.

Visualizing Java uncertainty

NASA Astrophysics Data System (ADS)

Knight, Claire; Munro, Malcolm

2001-07-01

Distributed component based systems seem to be the immediate future for software development. The use of such techniques, object oriented languages, and the combination with ever more powerful higher-level frameworks has led to the rapid creation and deployment of such systems to cater for the demand of internet and service driven business systems. This diversity of solution through both components utilised and the physical/virtual locations of those components can provide powerful resolutions to the new demand. The problem lies in the comprehension and maintenance of such systems because they then have inherent uncertainty. The components combined at any given time for a solution may differ, the messages generated, sent, and/or received may differ, and the physical/virtual locations cannot be guaranteed. Trying to account for this uncertainty and to build in into analysis and comprehension tools is important for both development and maintenance activities.

Comparative effectiveness of intervention components for producing long-term abstinence from smoking: a factorial screening experiment.

PubMed

Schlam, Tanya R; Fiore, Michael C; Smith, Stevens S; Fraser, David; Bolt, Daniel M; Collins, Linda M; Mermelstein, Robin; Piper, Megan E; Cook, Jessica W; Jorenby, Douglas E; Loh, Wei-Yin; Baker, Timothy B

2016-01-01

To identify promising intervention components that help smokers attain and maintain abstinence during a quit attempt. A 2 × 2 × 2 × 2 × 2 randomized factorial experiment. Eleven primary care clinics in Wisconsin, USA. A total of 544 smokers (59% women, 86% white) recruited during primary care visits and motivated to quit. Five intervention components designed to help smokers attain and maintain abstinence: (1) extended medication (26 versus 8 weeks of nicotine patch + nicotine gum); (2) maintenance (phone) counseling versus none; (3) medication adherence counseling versus none; (4) automated (medication) adherence calls versus none; and (5) electronic medication monitoring with feedback and counseling versus electronic medication monitoring alone. The primary outcome was 7-day self-reported point-prevalence abstinence 1 year after the target quit day. Only extended medication produced a main effect. Twenty-six versus 8 weeks of medication improved point-prevalence abstinence rates (43 versus 34% at 6 months; 34 versus 27% at 1 year; P = 0.01 for both). There were four interaction effects at 1 year, showing that an intervention component's effectiveness depended upon the components with which it was combined. Twenty-six weeks of nicotine patch + nicotine gum (versus 8 weeks) and maintenance counseling provided by phone are promising intervention components for the cessation and maintenance phases of smoking treatment. © 2015 Society for the Study of Addiction.

Test Driven Development of a Parameterized Ice Sheet Component

NASA Astrophysics Data System (ADS)

Clune, T.

2011-12-01

Test driven development (TDD) is a software development methodology that offers many advantages over traditional approaches including reduced development and maintenance costs, improved reliability, and superior design quality. Although TDD is widely accepted in many software communities, the suitability to scientific software is largely undemonstrated and warrants a degree of skepticism. Indeed, numerical algorithms pose several challenges to unit testing in general, and TDD in particular. Among these challenges are the need to have simple, non-redundant closed-form expressions to compare against the results obtained from the implementation as well as realistic error estimates. The necessity for serial and parallel performance raises additional concerns for many scientific applicaitons. In previous work I demonstrated that TDD performed well for the development of a relatively simple numerical model that simulates the growth of snowflakes, but the results were anecdotal and of limited relevance to far more complex software components typical of climate models. This investigation has now been extended by successfully applying TDD to the implementation of a substantial portion of a new parameterized ice sheet component within a full climate model. After a brief introduction to TDD, I will present techniques that address some of the obstacles encountered with numerical algorithms. I will conclude with some quantitative and qualitative comparisons against climate components developed in a more traditional manner.

Development of standardized component\\0x2010based equipment specifications and transition plan into a predictive maintenance strategy : final report.

DOT National Transportation Integrated Search

2015-12-01

This project investigated INDOT equipment records and equipment industry standards to produce standard equipment specifications : and a predictive maintenance schedule for the more than 1100 single and tandem axle trucks in use at INDOT. The research...

Type I Rehearsal and Recognition.

ERIC Educational Resources Information Center

Glenberg, Arthur; Adams, Frederick

1978-01-01

Rote, repetitive Type I Rehearsal is defined as the continuous maintenance of information in memory using the minimum cognitive capacity necessary for maintenance. An analysis of errors made on a forced-choice recognition test supported the hypothesis that acoustic-phonemic components of the memory trace are added or strengthened by this…

77 FR 73270 - Airworthiness Directives; Embraer S.A. Airplanes

Federal Register 2010, 2011, 2012, 2013, 2014

2012-12-10

... Airworthiness Limitation Section (ALS) of the EMBRAER ERJ 190 Maintenance Review Board Report (MRBR). This new AD requires revising the maintenance program to incorporate modifications in the ALS of the EMBRAER... issuing this AD since failure to inspect these structural components according to the new ALS tasks...

Laser-photodetector timing station instruction and maintenance manual

NASA Technical Reports Server (NTRS)

Strader, E. A.

1986-01-01

A laser photodetector station is used for detecting the arrival of a projectile at a specific point along a ballistic range. The system can be employed on either an open or evacuated range, with small projectiles, and at hypervelocities. The setup procedures, maintenance, and system components are described.

EVALUATION OF THE IMPLEMENTATION OF OPERATIONS AND MAINTENANCE PROGRAMS IN NEW JERSEY SCHOOLS

EPA Science Inventory

The Asbestos Hazard Emergency Response Act (AHERA) required all schools to develop and implement an asbestos management plan (AMP). The key component of the AMP is the operations and maintenance (O&M) program. A study was conducted to evaluate the implementation of O&M programs a...

30 CFR 250.516 - Blowout preventer system tests, inspections, and maintenance.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Well-Completion Operations § 250.516 Blowout preventer system tests, inspections, and maintenance. (a...) Test affected BOP components following the disconnection or repair of any well-pressure containment... you have well-control problems. You must conduct the required BOP test as soon as possible (i.e...

Structure and function of archaeal prefoldin, a co-chaperone of group II chaperonin.

PubMed

Ohtaki, Akashi; Noguchi, Keiichi; Yohda, Masafumi

2010-01-01

Molecular chaperones are key cellular components involved in the maintenance of protein homeostasis and other unrelated functions. Prefoldin is a chaperone that acts as a co-factor of group II chaperonins in eukaryotes and archaea. It assists proper folding of protein by capturing nonnative proteins and delivering it to the group II chaperonin. Eukaryotic prefoldin is a multiple subunit complex composed of six different polypeptide chains. Archaeal prefoldin, on the other hand, is a heterohexameric complex composed of two alpha and four beta subunits, and forms a double beta barrel assembly with six long coiled coils protruding from it like a jellyfish with six tentacles. Based on the structural information of the archaeal prefoldin, substrate recognition and prefoldin-chaperonin binding mechanisms have been investigated. In this paper, we review a series of studies on the molecular mechanisms of archaeal PFD function. Particular emphasis will be placed on the molecular structures revealed by X-ray crystallography and molecular dynamics induced by binding to nonnative protein substrates.

Transient oxytocin signaling primes the development and function of excitatory hippocampal neurons

PubMed Central

Ripamonti, Silvia; Ambrozkiewicz, Mateusz C; Guzzi, Francesca; Gravati, Marta; Biella, Gerardo; Bormuth, Ingo; Hammer, Matthieu; Tuffy, Liam P; Sigler, Albrecht; Kawabe, Hiroshi; Nishimori, Katsuhiko; Toselli, Mauro; Brose, Nils; Parenti, Marco; Rhee, JeongSeop

2017-01-01

Beyond its role in parturition and lactation, oxytocin influences higher brain processes that control social behavior of mammals, and perturbed oxytocin signaling has been linked to the pathogenesis of several psychiatric disorders. However, it is still largely unknown how oxytocin exactly regulates neuronal function. We show that early, transient oxytocin exposure in vitro inhibits the development of hippocampal glutamatergic neurons, leading to reduced dendrite complexity, synapse density, and excitatory transmission, while sparing GABAergic neurons. Conversely, genetic elimination of oxytocin receptors increases the expression of protein components of excitatory synapses and excitatory synaptic transmission in vitro. In vivo, oxytocin-receptor-deficient hippocampal pyramidal neurons develop more complex dendrites, which leads to increased spine number and reduced γ-oscillations. These results indicate that oxytocin controls the development of hippocampal excitatory neurons and contributes to the maintenance of a physiological excitation/inhibition balance, whose disruption can cause neurobehavioral disturbances. DOI: http://dx.doi.org/10.7554/eLife.22466.001 PMID:28231043

Promotion of BRCA2-Dependent Homologous Recombination by DSS1 via RPA Targeting and DNA Mimicry.

PubMed

Zhao, Weixing; Vaithiyalingam, Sivaraja; San Filippo, Joseph; Maranon, David G; Jimenez-Sainz, Judit; Fontenay, Gerald V; Kwon, Youngho; Leung, Stanley G; Lu, Lucy; Jensen, Ryan B; Chazin, Walter J; Wiese, Claudia; Sung, Patrick

2015-07-16

The tumor suppressor BRCA2 is thought to facilitate the handoff of ssDNA from replication protein A (RPA) to the RAD51 recombinase during DNA break and replication fork repair by homologous recombination. However, we find that RPA-RAD51 exchange requires the BRCA2 partner DSS1. Biochemical, structural, and in vivo analyses reveal that DSS1 allows the BRCA2-DSS1 complex to physically and functionally interact with RPA. Mechanistically, DSS1 acts as a DNA mimic to attenuate the affinity of RPA for ssDNA. A mutation in the solvent-exposed acidic domain of DSS1 compromises the efficacy of RPA-RAD51 exchange. Thus, by targeting RPA and mimicking DNA, DSS1 functions with BRCA2 in a two-component homologous recombination mediator complex in genome maintenance and tumor suppression. Our findings may provide a paradigm for understanding the roles of DSS1 in other biological processes. Copyright © 2015 Elsevier Inc. All rights reserved.

Methods for Calculating Frequency of Maintenance of Complex Information Security System Based on Dynamics of Its Reliability

NASA Astrophysics Data System (ADS)

Varlataya, S. K.; Evdokimov, V. E.; Urzov, A. Y.

2017-11-01

This article describes a process of calculating a certain complex information security system (CISS) reliability using the example of the technospheric security management model as well as ability to determine the frequency of its maintenance using the system reliability parameter which allows one to assess man-made risks and to forecast natural and man-made emergencies. The relevance of this article is explained by the fact the CISS reliability is closely related to information security (IS) risks. Since reliability (or resiliency) is a probabilistic characteristic of the system showing the possibility of its failure (and as a consequence - threats to the protected information assets emergence), it is seen as a component of the overall IS risk in the system. As it is known, there is a certain acceptable level of IS risk assigned by experts for a particular information system; in case of reliability being a risk-forming factor maintaining an acceptable risk level should be carried out by the routine analysis of the condition of CISS and its elements and their timely service. The article presents a reliability parameter calculation for the CISS with a mixed type of element connection, a formula of the dynamics of such system reliability is written. The chart of CISS reliability change is a S-shaped curve which can be divided into 3 periods: almost invariable high level of reliability, uniform reliability reduction, almost invariable low level of reliability. Setting the minimum acceptable level of reliability, the graph (or formula) can be used to determine the period of time during which the system would meet requirements. Ideally, this period should not be longer than the first period of the graph. Thus, the proposed method of calculating the CISS maintenance frequency helps to solve a voluminous and critical task of the information assets risk management.

Temperature environment for 9975 packages stored in KAC

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

Daugherty, W. L.

Plutonium materials are stored in the K Area Complex (KAC) in shipping packages, typically the 9975 shipping package. In order to estimate realistic degradation rates for components within the shipping package (i.e. the fiberboard overpack and O-ring seals), it is necessary to understand actual facility temperatures, which can vary daily and seasonally. Relevant facility temperature data available from several periods throughout its operating history have been reviewed. The annual average temperature within the Crane Maintenance Area has ranged from approximately 70 to 74 °F, although there is significant seasonal variation and lesser variation among different locations within the facility. Themore » long-term average degradation rate for 9975 package components is very close to that expected if the component were to remain continually at the annual average temperature. This result remains valid for a wide range of activation energies (which describes the variation in degradation rate as the temperature changes), if the activation energy remains constant over the seasonal range of component temperatures. It is recommended that component degradation analyses and service life estimates incorporate these results. Specifically, it is proposed that future analyses assume an average facility ambient air temperature of 94 °F. This value is bounding for all packages, and includes margin for several factors such as increased temperatures within the storage arrays, the addition of more packages in the future, and future operational changes.« less

TCMS operations and maintenance philosophy

NASA Technical Reports Server (NTRS)

Buehler, David P.; Griffin, Rock E.

1992-01-01

The purpose is to describe the basic philosophies of operating and maintaining the Test, Control, and Monitor System (TCMS) equipment. TCMS is a complex and sophisticated checkout system. Operations and maintenance processes developed to support it will be based upon current experience, but will be focused on the specific needs of TCMS in support of Space Station Freedom Program (SSFP) and related activities. An overview of the operations and maintenance goals and philosophies are presented. The assumptions, roles and responsibilities, concepts and interfaces for operation, on-line maintenance, off-line support, and Operations and Maintenance (O&M) personnel training on all TCMS equipment located at KSC are described.

[Medical Equipment Maintenance Methods].

PubMed

Liu, Hongbin

2015-09-01

Due to the high technology and the complexity of medical equipment, as well as to the safety and effectiveness, it determines the high requirements of the medical equipment maintenance work. This paper introduces some basic methods of medical instrument maintenance, including fault tree analysis, node method and exclusive method which are the three important methods in the medical equipment maintenance, through using these three methods for the instruments that have circuit drawings, hardware breakdown maintenance can be done easily. And this paper introduces the processing methods of some special fault conditions, in order to reduce little detours in meeting the same problems. Learning is very important for stuff just engaged in this area.

Comprehensive Characterization of Minichromosome Maintenance Complex (MCM) Protein Interactions Using Affinity and Proximity Purifications Coupled to Mass Spectrometry.

PubMed

Dubois, Marie-Line; Bastin, Charlotte; Lévesque, Dominique; Boisvert, François-Michel

2016-09-02

The extensive identification of protein-protein interactions under different conditions is an important challenge to understand the cellular functions of proteins. Here we use and compare different approaches including affinity purification and purification by proximity coupled to mass spectrometry to identify protein complexes. We explore the complete interactome of the minichromosome maintenance (MCM) complex by using both approaches for all of the different MCM proteins. Overall, our analysis identified unique and shared interaction partners and proteins enriched for distinct biological processes including DNA replication, DNA repair, and cell cycle regulation. Furthermore, we mapped the changes in protein interactions of the MCM complex in response to DNA damage, identifying a new role for this complex in DNA repair. In summary, we demonstrate the complementarity of these approaches for the characterization of protein interactions within the MCM complex.

Combining virtual reality and multimedia techniques for effective maintenance training

NASA Astrophysics Data System (ADS)

McLin, David M.; Chung, James C.

1996-02-01

This paper describes a virtual reality (VR) system developed for use as part of an integrated, low-cost, stand-alone, multimedia trainer. The trainer is used to train National Guard personnel in maintenance and trouble-shooting tasks for the M1A1 Abrams tank, the M2A2 Bradley fighting vehicle and the TOW II missile system. The VR system features a modular, extensible, object-oriented design which consists of a training monitor component, a VR run time component, a model loader component, and a set of domain-specific object behaviors which mimic the behavior of objects encountered in the actual vehicles. The VR system is built from a combination of off-the-shelf commercial software and custom software developed at RTI.

Networks consolidation program: Maintenance and Operations (M&O) staffing estimates

NASA Technical Reports Server (NTRS)

Goodwin, J. P.

1981-01-01

The Mark IV-A consolidate deep space and high elliptical Earth orbiter (HEEO) missions tracking and implements centralized control and monitoring at the deep space communications complexes (DSCC). One of the objectives of the network design is to reduce maintenance and operations (M&O) costs. To determine if the system design meets this objective an M&O staffing model for Goldstone was developed which was used to estimate the staffing levels required to support the Mark IV-A configuration. The study was performed for the Goldstone complex and the program office translated these estimates for the overseas complexes to derive the network estimates.

Expert system applications for army vehicle diagnostics

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

Halle, R.F.

1987-01-01

Bulky manuals, limited training procedures, and complex Automatic Test Equipment are but a few of the problems a mechanic must face when trying to repair many of the military's new and highly complex vehicle systems. Recent technological advances in Expert Systms has given the mechanic the potential to solve many of these problems and to actually enhance his maintenance proficiency. This paper describes both the history of and the future potential of the Expert System and how it could impact on the present military maintenance system.

Single-molecule visualization of Saccharomyces cerevisiae leading-strand synthesis reveals dynamic interaction between MTC and the replisome

PubMed Central

Lewis, Jacob S.; Spenkelink, Lisanne M.; Schauer, Grant D.; Hill, Flynn R.; Georgescu, Roxanna E.; O’Donnell, Michael E.; van Oijen, Antoine M.

2017-01-01

The replisome, the multiprotein system responsible for genome duplication, is a highly dynamic complex displaying a large number of different enzyme activities. Recently, the Saccharomyces cerevisiae minimal replication reaction has been successfully reconstituted in vitro. This provided an opportunity to uncover the enzymatic activities of many of the components in a eukaryotic system. Their dynamic behavior and interactions in the context of the replisome, however, remain unclear. We use a tethered-bead assay to provide real-time visualization of leading-strand synthesis by the S. cerevisiae replisome at the single-molecule level. The minimal reconstituted leading-strand replisome requires 24 proteins, forming the CMG helicase, the Pol ε DNA polymerase, the RFC clamp loader, the PCNA sliding clamp, and the RPA single-stranded DNA binding protein. We observe rates and product lengths similar to those obtained from ensemble biochemical experiments. At the single-molecule level, we probe the behavior of two components of the replication progression complex and characterize their interaction with active leading-strand replisomes. The Minichromosome maintenance protein 10 (Mcm10), an important player in CMG activation, increases the number of productive replication events in our assay. Furthermore, we show that the fork protection complex Mrc1–Tof1–Csm3 (MTC) enhances the rate of the leading-strand replisome threefold. The introduction of periods of fast replication by MTC leads to an average rate enhancement of a factor of 2, similar to observations in cellular studies. We observe that the MTC complex acts in a dynamic fashion with the moving replisome, leading to alternating phases of slow and fast replication. PMID:28923950

Integrating O/S models during conceptual design, part 3

NASA Technical Reports Server (NTRS)

Ebeling, Charles E.

1994-01-01

Space vehicles, such as the Space Shuttle, require intensive ground support prior to, during, and after each mission. Maintenance is a significant part of that ground support. All space vehicles require scheduled maintenance to ensure operability and performance. In addition, components of any vehicle are not one-hundred percent reliable so they exhibit random failures. Once detected, a failure initiates unscheduled maintenance on the vehicle. Maintenance decreases the number of missions which can be completed by keeping vehicles out of service so that the time between the completion of one mission and the start of the next is increased. Maintenance also requires resources such as people, facilities, tooling, and spare parts. Assessing the mission capability and resource requirements of any new space vehicle, in addition to performance specification, is necessary to predict the life cycle cost and success of the vehicle. Maintenance and logistics support has been modeled by computer simulation to estimate mission capability and resource requirements for evaluation of proposed space vehicles. The simulation was written with Simulation Language for Alternative Modeling II (SLAM II) for execution on a personal computer. For either one or a fleet of space vehicles, the model simulates the preflight maintenance checks, the mission and return to earth, and the post flight maintenance in preparation to be sent back into space. THe model enables prediction of the number of missions possible and vehicle turn-time (the time between completion of one mission and the start of the next) given estimated values for component reliability and maintainability. The model also facilitates study of the manpower and vehicle requirements for the proposed vehicle to meet its desired mission rate. This is the 3rd part of a 3 part technical report.

A Theoretical Reassessment of Microbial Maintenance and Implications for Microbial Ecology Modeling

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

Wang, Gangsheng; Post, Wilfred M

We attempted to reconcile three microbial maintenance models (Herbert, Pirt, and Compromise) through a critical reassessment. We provided a rigorous proof that the true growth yield coefficient (YG) is the ratio of the specific maintenance rate (a in Herbert) to the maintenance coefficient (m in Pirt). Other findings from this study include: (1) the Compromise model is identical to the Herbert for computing microbial growth and substrate consumption, but it expresses the dependence of maintenance on both microbial biomass and substrate; (2) the maximum specific growth rate in the Herbert ( max,H) is higher than those in the other twomore » models ( max,P and max,C), and the difference is the physiological maintenance factor (mq = a); and (3) the overall maintenance coefficient (mT) is more sensitive to mq than to the specific growth rate ( G) and YG. Our critical reassessment of microbial maintenance provides a new approach for quantifying some important components in soil microbial ecology models.« less

Distinct Gamma-Band Components Reflect the Short-Term Memory Maintenance of Different Sound Lateralization Angles

PubMed Central

Heidegger, Tonio; Wibral, Michael; Altmann, Christian F.; Lutzenberger, Werner

2008-01-01

Oscillatory activity in human electro- or magnetoencephalogram has been related to cortical stimulus representations and their modulation by cognitive processes. Whereas previous work has focused on gamma-band activity (GBA) during attention or maintenance of representations, there is little evidence for GBA reflecting individual stimulus representations. The present study aimed at identifying stimulus-specific GBA components during auditory spatial short-term memory. A total of 28 adults were assigned to 1 of 2 groups who were presented with only right- or left-lateralized sounds, respectively. In each group, 2 sample stimuli were used which differed in their lateralization angles (15° or 45°) with respect to the midsagittal plane. Statistical probability mapping served to identify spectral amplitude differences between 15° versus 45° stimuli. Distinct GBA components were found for each sample stimulus in different sensors over parieto-occipital cortex contralateral to the side of stimulation peaking during the middle 200–300 ms of the delay phase. The differentiation between “preferred” and “nonpreferred” stimuli during the final 100 ms of the delay phase correlated with task performance. These findings suggest that the observed GBA components reflect the activity of distinct networks tuned to spatial sound features which contribute to the maintenance of task-relevant information in short-term memory. PMID:18252742

Maintenance of Certification for Radiation Oncology

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

Kun, Larry E.; Ang, Kian; Erickson, Beth

2005-06-01

Maintenance of Certification (MOC) recognizes that in addition to medical knowledge, several essential elements involved in delivering quality care must be developed and maintained throughout one's career. The MOC process is designed to facilitate and document professional development of American Board of Radiology (ABR) diplomates in the essential elements of quality care in Radiation Oncology and Radiologic Physics. ABR MOC has been developed in accord with guidelines of the American Board of Medical Specialties. All Radiation Oncology certificates issued since 1995 are 10-year, time-limited certificates; diplomates with time-limited certificates who wish to maintain specialty certification must complete specific requirements ofmore » the American Board of Radiology MOC program. Diplomates with lifelong certificates are not required to participate but are strongly encouraged to do so. Maintenance of Certification is based on documentation of participation in the four components of MOC: (1) professional standing, (2) lifelong learning and self-assessment, (3) cognitive expertise, and (4) performance in practice. Through these components, MOC addresses six competencies-medical knowledge, patient care, interpersonal and communication skills, professionalism, practice-based learning and improvement, and systems-based practice. Details of requirements for components 1, 2, and 3 of MOC are outlined along with aspects of the fourth component currently under development.« less

Borescope Inspection Management for Engine

NASA Astrophysics Data System (ADS)

Zhongda, Yuan

2018-03-01

In this paper, we try to explain the problems need to be improved from the two perspectives of maintenance program management and maintenance human risk control. On the basis of optimization analysis of borescope inspection maintenance scheme, the defect characteristics and expansion rules of engine heat terminal components are summarized, and some optimization measures are introduced. This paper analyses human risk problem of engine hole from the aspects of qualification management, training requirements and perfection of system, and puts forward some suggestions on management.

Final expanded site inspection, ammunition storage area, Anniston Army Depot, Anniston, Alabama. Final report, September 1992-November 1994

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

Suomela, K.D.; Highsmith, R.L.; Rapuano, K.F.

1994-11-15

An Expanded Site Inspection (ESI) was conducted at the Anniston Army Depot (ANAD) Ammunition Storage Area (ASA). The objective of this ESI was to gather the information and data necessary to determine whether there is sufficient evidence of any release of contamination that would require additional investigation. The ASA contains 1,300 ammunition storage magazines and an ammunition maintenance workshop complex which includes buildings for maintenance, demilitarization, and inspection of all types of ammunition and their components. Fifteen Solid Waste Management Units (SWMUs) were the focus of the ESI, of which 11 were recommend for further investigation. The work included amore » review of historical records, field investigations, laboratory analyses, data interpretation, and report preparation. Contamination from volatile organic compounds and semi volatile organic compounds is not a major problem at the ASA. Arsenic, beryllium, cadmium, chromium, lead, mercury, nickel, silver, vanadium, zinc, explosives, and total petroleum hydrocarbons were detected above control screening values levels in one or more of the media sampled. Nitrate/nitrite and total organic carbon were also detected above control screening values in samples of groundwater, soil, and sediment from a number of SWMUs.« less

Proposal for hierarchical description of software systems

NASA Technical Reports Server (NTRS)

Thauboth, H.

1973-01-01

The programming of digital computers has developed into a new dimension full of diffculties, because the hardware of computers has become so powerful that more complex applications are entrusted to computers. The costs of software development, verification, and maintenance are outpacing those of the hardware and the trend is toward futher increase of sophistication of application of computers and consequently of sophistication of software. To obtain better visibility into software systems and to improve the structure of software systems for better tests, verification, and maintenance, a clear, but rigorous description and documentation of software is needed. The purpose of the report is to extend the present methods in order to obtain a documentation that better reflects the interplay between the various components and functions of a software system at different levels of detail without losing the precision in expression. This is done by the use of block diagrams, sequence diagrams, and cross-reference charts. In the appendices, examples from an actual large sofware system, i.e. the Marshall System for Aerospace Systems Simulation (MARSYAS), are presented. The proposed documentation structure is compatible to automation of updating significant portions of the documentation for better software change control.

The axonal transport of mitochondria

PubMed Central

Saxton, William M.; Hollenbeck, Peter J.

2012-01-01

Vigorous transport of cytoplasmic components along axons over substantial distances is crucial for the maintenance of neuron structure and function. The transport of mitochondria, which serves to distribute mitochondrial functions in a dynamic and non-uniform fashion, has attracted special interest in recent years following the discovery of functional connections among microtubules, motor proteins and mitochondria, and their influences on neurodegenerative diseases. Although the motor proteins that drive mitochondrial movement are now well characterized, the mechanisms by which anterograde and retrograde movement are coordinated with one another and with stationary axonal mitochondria are not yet understood. In this Commentary, we review why mitochondria move and how they move, focusing particularly on recent studies of transport regulation, which implicate control of motor activity by specific cell-signaling pathways, regulation of motor access to transport tracks and static microtubule–mitochondrion linkers. A detailed mechanism for modulating anterograde mitochondrial transport has been identified that involves Miro, a mitochondrial Ca2+-binding GTPase, which with associated proteins, can bind and control kinesin-1. Elements of the Miro complex also have important roles in mitochondrial fission–fusion dynamics, highlighting questions about the interdependence of biogenesis, transport, dynamics, maintenance and degradation. PMID:22619228

A role for post-transcriptional control of endoplasmic reticulum dynamics and function in C. elegans germline stem cell maintenance.

PubMed

Maheshwari, Richa; Pushpa, Kumari; Subramaniam, Kuppuswamy

2016-09-01

Membrane-bound receptors, which are crucial for mediating several key developmental signals, are synthesized on endoplasmic reticulum (ER). The functional integrity of ER must therefore be important for the regulation of at least some developmental programs. However, the developmental control of ER function is not well understood. Here, we identify the C. elegans protein FARL-11, an ortholog of the mammalian STRIPAK complex component STRIP1/2 (FAM40A/B), as an ER protein. In the C. elegans embryo, we find that FARL-11 is essential for the cell cycle-dependent morphological changes of ER and for embryonic viability. In the germline, FARL-11 is required for normal ER morphology and for membrane localization of the GLP-1/Notch receptor involved in germline stem cell (GSC) maintenance. Furthermore, we provide evidence that PUF-8, a key translational regulator in the germline, promotes the translation of farl-11 mRNA. These findings reveal that ER form and function in the C. elegans germline are post-transcriptionally regulated and essential for the niche-GSC signaling mediated by GLP-1. © 2016. Published by The Company of Biologists Ltd.

Environmentally Preferable Coatings for Structural Steel Project

NASA Technical Reports Server (NTRS)

Lewis, Pattie L. (Editor)

2014-01-01

The Ground Systems Development and Operations (GSDO) Program at NASA John F. Kennedy Space Center (KSC) has the primary objective of modernizing and transforming the launch and range complex at KSC to benefit current and future NASA programs along with other emerging users. Described a the "launch support and infrastructure modernization program" in the NASA Authorization Act of 2010, the GSDO Program will develop and implement shared infrastructure and process improvements to provide more flexible, affordable, and responsive capabilities to a multi-user community. In support of the GSDO Program, the objective of this project is to determine the feasibility of environmentally friendly corrosion resistant coatings for launch facilities and ground support equipment. The focus of the project is corrosion resistance and survivability with the goal to reduce the amount of maintenance required to preserve the performance of launch facilities while reducing mission risk. Number of facilities/structures with metallic structural and non-structural components in a highly corrosive environment. Metals require periodic maintenance activity to guard against the insidious effects of corrosion and thus ensure that structures meet or exceed design or performance life. The standard practice for protecting metallic substrates in atmospheric environments is the application of corrosion protective coating system.

AUTOMOTIVE DIESEL MAINTENANCE 1. UNIT VIII. ENGINE COMPONENTS--PART I.

ERIC Educational Resources Information Center

Human Engineering Inst., Cleveland, OH.

THIS MODULE OF A 30-MODULE COURSE IS DESIGNED TO DEVELOP AN UNDERSTANDING OF THE CONSTRUCTION AND MAINTENANCE OF DIESEL ENGINE CYLINDER HEADS AND CYLINDER ASSEMBLIES. TOPICS ARE CYLINDER ASSEMBLY (LINERS), CYLINDER HEADS, VALVES AND VALVE MECHANISMS, AND PISTON AND PISTON RINGS. THE MODULE CONSISTS OF A SELF-INSTRUCTIONAL BRANCH PROGRAMED TRAINING…

Development of a smart timber bridge girder with fiber optic sensors

Treesearch

James Wacker; Ursula Deza; Brent M. Phares; Terry J. Wipf

2010-01-01

Past timber bridge evaluation and maintenance efforts in the USA have principally focused on the internal integrity of timber components using various non-destructive evaluation tools to supplement visual inspection data. This project is part of a comprehensive effort to develop smart structure concepts for improving the long-term performance, maintenance, and...

Industrial Electrical Maintenance Learning Guides and Task Listing by Occupational Titles.

ERIC Educational Resources Information Center

Whitmer, Melvin

Seven student learning guides are provided for an industrial electrical maintenance program at the secondary, postsecondary, or adult level. Each learning guide is composed of these component parts: a title page that states the task, purpose, program and task numbers, estimated time, and prerequisites; an optional learning contract that includes…

Breaking the Backlog Reduction Mold with FacMan: A Facilities Management Application for Maintenance Backlogs and Capital Renewal.

ERIC Educational Resources Information Center

Managan, William H.

1999-01-01

Describes a facilities-management software program that helps managers better document and understand maintenance backlogs, improvements, and future cyclic renewal needs. Major software components are examined including a software tool that filters, groups, and ranks projects to help determine funding requests. (GR)

Industrial Equipment Maintenance. Vocational Education Curriculum Guide. Industrial and Technical Education.

ERIC Educational Resources Information Center

West Virginia State Vocational Curriculum Lab., Cedar Lakes.

This curriculum guide contains 10 units that provide the basic curriculum components required to develop lesson plans for the industrial equipment maintenance curriculum. The guide is not intended to be a complete, self-contained curriculum, but instead provides the teacher with a number of informational items related to the learning outcomes and…

Essential role of lncRNA binding for WDR5 maintenance of active chromatin and embryonic stem cell pluripotency

PubMed Central

Yang, Yul W; Flynn, Ryan A; Chen, Yong; Qu, Kun; Wan, Bingbing; Wang, Kevin C; Lei, Ming; Chang, Howard Y

2014-01-01

The WDR5 subunit of the MLL complex enforces active chromatin and can bind RNA; the relationship between these two activities is unclear. Here we identify a RNA binding pocket on WDR5, and discover a WDR5 mutant (F266A) that selectively abrogates RNA binding without affecting MLL complex assembly or catalytic activity. Complementation in ESCs shows that WDR5 F266A mutant is unable to accumulate on chromatin, and is defective in gene activation, maintenance of histone H3 lysine 4 trimethylation, and ESC self renewal. We identify a family of ESC messenger and lncRNAs that interact with wild type WDR5 but not F266A mutant, including several lncRNAs known to be important for ESC gene expression. These results suggest that specific RNAs are integral inputs into the WDR5-MLL complex for maintenance of the active chromatin state and embryonic stem cell fates. DOI: http://dx.doi.org/10.7554/eLife.02046.001 PMID:24521543

Hidden Dangers.

ERIC Educational Resources Information Center

Greven, Erik D. W.; Knox, Winthrop S.

1999-01-01

Discusses each of the major system components of a maintenance survey that can provide pool facilities with the information needed to properly maintain aging pools. Components examined include mechanical and structural systems; pool structure; and the filtration, circulation, and chemical treatment systems. (GR)

Mechanical systems readiness assessment and performance monitoring study

NASA Technical Reports Server (NTRS)

1972-01-01

The problem of mechanical devices which lack the real-time readiness assessment and performance monitoring capability required for future space missions is studied. The results of a test program to establish the feasibility of implementing structure borne acoustics, a nondestructive test technique, are described. The program included the monitoring of operational acoustic signatures of five separate mechanical components, each possessing distinct sound characteristics. Acoustic signatures were established for normal operation of each component. Critical failure modes were then inserted into the test components, and faulted acoustic signatures obtained. Predominant features of the sound signature were related back to operational events occurring within the components both for normal and failure mode operations. All of these steps can be automated. The structure borne acoustics technique lends itself to reducing checkout time, simplifying maintenance procedures, and reducing manual involvement in the checkout, operation, maintenance, and fault diagnosis of mechanical systems.

Reliability-based optimization of maintenance scheduling of mechanical components under fatigue

PubMed Central

Beaurepaire, P.; Valdebenito, M.A.; Schuëller, G.I.; Jensen, H.A.

2012-01-01

This study presents the optimization of the maintenance scheduling of mechanical components under fatigue loading. The cracks of damaged structures may be detected during non-destructive inspection and subsequently repaired. Fatigue crack initiation and growth show inherent variability, and as well the outcome of inspection activities. The problem is addressed under the framework of reliability based optimization. The initiation and propagation of fatigue cracks are efficiently modeled using cohesive zone elements. The applicability of the method is demonstrated by a numerical example, which involves a plate with two holes subject to alternating stress. PMID:23564979

An artificial intelligence-based structural health monitoring system for aging aircraft

NASA Technical Reports Server (NTRS)

Grady, Joseph E.; Tang, Stanley S.; Chen, K. L.

1993-01-01

To reduce operating expenses, airlines are now using the existing fleets of commercial aircraft well beyond their originally anticipated service lives. The repair and maintenance of these 'aging aircraft' has therefore become a critical safety issue, both to the airlines and the Federal Aviation Administration. This paper presents the results of an innovative research program to develop a structural monitoring system that will be used to evaluate the integrity of in-service aerospace structural components. Currently in the final phase of its development, this monitoring system will indicate when repair or maintenance of a damaged structural component is necessary.

Costs of storing colour and complex shape in visual working memory: Insights from pupil size and slow waves.

PubMed

Kursawe, Michael A; Zimmer, Hubert D

2015-06-01

We investigated the impact of perceptual processing demands on visual working memory of coloured complex random polygons during change detection. Processing load was assessed by pupil size (Exp. 1) and additionally slow wave potentials (Exp. 2). Task difficulty was manipulated by presenting different set sizes (1, 2, 4 items) and by making different features (colour, shape, or both) task-relevant. Memory performance in the colour condition was better than in the shape and both condition which did not differ. Pupil dilation and the posterior N1 increased with set size independent of type of feature. In contrast, slow waves and a posterior P2 component showed set size effects but only if shape was task-relevant. In the colour condition slow waves did not vary with set size. We suggest that pupil size and N1 indicates different states of attentional effort corresponding to the number of presented items. In contrast, slow waves reflect processes related to encoding and maintenance strategies. The observation that their potentials vary with the type of feature (simple colour versus complex shape) indicates that perceptual complexity already influences encoding and storage and not only comparison of targets with memory entries at the moment of testing. Copyright © 2015 Elsevier B.V. All rights reserved.

Design local exhaust ventilation on sieve machine at PT.Perkebunan Nusantara VIII Ciater using design for assembly (DFA) approach with Boothroyd and Dewhurst method

NASA Astrophysics Data System (ADS)

Khalqihi, K. I.; Rahayu, M.; Rendra, M.

2017-12-01

PT Perkebunan Nusantara VIII Ciater is a company produced black tea orthodox more or less 4 tons every day. At the production section, PT Perkebunan Nusantara VIII will use local exhaust ventilation specially at sortation area on sieve machine. To maintain the quality of the black tea orthodox, all machine must be scheduled for maintenance every once a month and takes time 2 hours in workhours, with additional local exhaust ventilation, it will increase time for maintenance process, if maintenance takes time more than 2 hours it will caused production process delayed. To support maintenance process in PT Perkebunan Nusantara VIII Ciater, designing local exhaust ventilation using design for assembly approach with Boothroyd and Dewhurst method, design for assembly approach is choosen to simplify maintenance process which required assembly process. There are 2 LEV designs for this research. Design 1 with 94 components, assembly time 647.88 seconds and assembly efficiency level 23.62%. Design 2 with 82 components, assembly time 567.84 seconds and assembly efficiency level 24.83%. Design 2 is choosen for this research based on DFA goals, minimum total part that use, optimization assembly time, and assembly efficiency level.

[Characteristics of a negative effect of aviation noise on hearing organ of aircraft maintenance personnel].

PubMed

Zinkin, V N; Soldatov, S K; Sheshegov, P M

2007-01-01

Otolaryngological examination was carried out of 80 engineers and technicians engaged in maintenance of aircrafts in the airports. They are continuously exposed to occupational aviation noise and therefore are at risk for chronic neurosensory hypoacusis. Pure tone audiogram registers in them a rise in hearing thresholds throughout the whole band of frequencies studied. This means that aviation maintenance staff is exposed to noise containing highly intensive infrasound and high-frequency components. The detected pathology directly correlated with duration of exposure to noise. Development of neurosensory hypoacusis in aviation maintenance specialists starts earlier than in other specialists exposed to noise.

A Methodology for Modeling Nuclear Power Plant Passive Component Aging in Probabilistic Risk Assessment under the Impact of Operating Conditions, Surveillance and Maintenance Activities

NASA Astrophysics Data System (ADS)

Guler Yigitoglu, Askin

In the context of long operation of nuclear power plants (NPPs) (i.e., 60-80 years, and beyond), investigation of the aging of passive systems, structures and components (SSCs) is important to assess safety margins and to decide on reactor life extension as indicated within the U.S. Department of Energy (DOE) Light Water Reactor Sustainability (LWRS) Program. In the traditional probabilistic risk assessment (PRA) methodology, evaluating the potential significance of aging of passive SSCs on plant risk is challenging. Although passive SSC failure rates can be added as initiating event frequencies or basic event failure rates in the traditional event-tree/fault-tree methodology, these failure rates are generally based on generic plant failure data which means that the true state of a specific plant is not reflected in a realistic manner on aging effects. Dynamic PRA methodologies have gained attention recently due to their capability to account for the plant state and thus address the difficulties in the traditional PRA modeling of aging effects of passive components using physics-based models (and also in the modeling of digital instrumentation and control systems). Physics-based models can capture the impact of complex aging processes (e.g., fatigue, stress corrosion cracking, flow-accelerated corrosion, etc.) on SSCs and can be utilized to estimate passive SSC failure rates using realistic NPP data from reactor simulation, as well as considering effects of surveillance and maintenance activities. The objectives of this dissertation are twofold: The development of a methodology for the incorporation of aging modeling of passive SSC into a reactor simulation environment to provide a framework for evaluation of their risk contribution in both the dynamic and traditional PRA; and the demonstration of the methodology through its application to pressurizer surge line pipe weld and steam generator tubes in commercial nuclear power plants. In the proposed methodology, a multi-state physics based model is selected to represent the aging process. The model is modified via sojourn time approach to reflect the operational and maintenance history dependence of the transition rates. Thermal-hydraulic parameters of the model are calculated via the reactor simulation environment and uncertainties associated with both parameters and the models are assessed via a two-loop Monte Carlo approach (Latin hypercube sampling) to propagate input probability distributions through the physical model. The effort documented in this thesis towards this overall objective consists of : i) defining a process for selecting critical passive components and related aging mechanisms, ii) aging model selection, iii) calculating the probability that aging would cause the component to fail, iv) uncertainty/sensitivity analyses, v) procedure development for modifying an existing PRA to accommodate consideration of passive component failures, and, vi) including the calculated failure probability in the modified PRA. The proposed methodology is applied to pressurizer surge line pipe weld aging and steam generator tube degradation in pressurized water reactors.

Characterization of the TolB-Pal trans-envelope complex from Xylella fastidiosa reveals a dynamic and coordinated protein expression profile during the biofilm development process.

PubMed

Santos, Clelton A; Janissen, Richard; Toledo, Marcelo A S; Beloti, Lilian L; Azzoni, Adriano R; Cotta, Monica A; Souza, Anete P

2015-10-01

The intriguing roles of the bacterial Tol-Pal trans-envelope protein complex range from maintenance of cell envelope integrity to potential participation in the process of cell division. In this study, we report the characterization of the XfTolB and XfPal proteins of the Tol-Pal complex of Xylella fastidiosa. X. fastidiosa is a major plant pathogen that forms biofilms inside xylem vessels, triggering the development of diseases in important cultivable plants around the word. Based on functional complementation experiments in Escherichia coli tolB and pal mutant strains, we confirmed the role of xftolB and xfpal in outer membrane integrity. In addition, we observed a dynamic and coordinated protein expression profile during the X. fastidiosa biofilm development process. Using small-angle X-ray scattering (SAXS), the low-resolution structure of the isolated XfTolB-XfPal complex in solution was solved for the first time. Finally, the localization of the XfTolB and XfPal polar ends was visualized via immunofluorescence labeling in vivo during bacterial cell growth. Our results highlight the major role of the components of the cell envelope, particularly the TolB-Pal complex, during the different phases of bacterial biofilm development. Copyright © 2015 Elsevier B.V. All rights reserved.

A Genome-wide RNAi Screen for Polypeptides that Alter rpS6 Phosphorylation

PubMed Central

Papageorgiou, Angela; Avruch, Joseph

2012-01-01

Mammalian target of rapamycin (mTOR) is a giant protein kinase that controls cell proliferation, growth, and metabolism. mTOR is regulated by nutrient availability, by mitogens, and by stress, and operates through two independently regulated hetero-oligomeric complexes. We have attempted to identify the cellular components necessary to maintain the activity of mTOR complex 1 (mTORC1), the amino acid-dependent, rapamycin-inhibitable complex, using a whole genome approach involving RNAi-induced depletion of cellular polypeptides. We have used a pancreatic ductal adenocarcinoma (PDAC) cell line, Mia-PaCa for this screen; as with many pancreatic cancers, these cells exhibit constitutive activation of mTORC1. PDAC is the most common form of pancreatic cancer and the 5-year survival rate remains 3–5% despite current nonspecific and targeted therapies. Although rapamycin-related mTOR inhibitors have yet to demonstrate encouraging clinical responses, it is now evident that this class of compounds is capable of only partial mTORC1 inhibition. Identifying previously unappreciated proteins needed for maintenance of mTORC1 activity may provide new targets and lead to the development of beneficial therapies for pancreatic cancer. PMID:22125066

24 CFR 3282.402 - General provisions.

Code of Federal Regulations, 2014 CFR

2014-04-01

... component as the result of normal wear and aging, consumer abuse, or neglect of maintenance. The life of a component warranty may be one of the indicators used to establish normal wear and aging. A failure of any component may not be attributed by the manufacturer to normal wear and aging under this subpart during the...

Characterizing and Assessing a Large-Scale Software Maintenance Organization

NASA Technical Reports Server (NTRS)

Briand, Lionel; Melo, Walcelio; Seaman, Carolyn; Basili, Victor

1995-01-01

One important component of a software process is the organizational context in which the process is enacted. This component is often missing or incomplete in current process modeling approaches. One technique for modeling this perspective is the Actor-Dependency (AD) Model. This paper reports on a case study which used this approach to analyze and assess a large software maintenance organization. Our goal was to identify the approach's strengths and weaknesses while providing practical recommendations for improvement and research directions. The AD model was found to be very useful in capturing the important properties of the organizational context of the maintenance process, and aided in the understanding of the flaws found in this process. However, a number of opportunities for extending and improving the AD model were identified. Among others, there is a need to incorporate quantitative information to complement the qualitative model.

A computer-based maintenance reminder and record-keeping system for clinical laboratories.

PubMed

Roberts, B I; Mathews, C L; Walton, C J; Frazier, G

1982-09-01

"Maintenance" is all the activity an organization devotes to keeping instruments within performance specifications to assure accurate and precise operation. The increasing use of complex analytical instruments as "workhorses" in clinical laboratories requires more maintenance awareness by laboratory personnel. Record-keeping systems that document maintenance completion and that should prompt the continued performance of maintenance tasks have not kept up with instrumentation development. We report here a computer-based record-keeping and reminder system that lists weekly the maintenance items due for each work station in the laboratory, including the time required to complete each item. Written in BASIC, the system uses a DATABOSS data base management system running on a time-shared Digital Equipment Corporation PDP 11/60 computer with a RSTS V 7.0 operating system.

Troubleshooting Complex Equipment in the Military Services: Research and Prospects.

DTIC Science & Technology

1979-12-01

the maintenance concept for a given prime * ,equipeent. The concept defines levels of maintenance, the arrangements for support by mobile and depot...Naval Training Bquipment Center, 1975. Ross, S. AUmlied probability models with otimization aplications . San Francisco: Holden-Day, 1970. use, W.B. Human

A maintenance model for k-out-of-n subsystems aboard a fleet of advanced commercial aircraft

NASA Technical Reports Server (NTRS)

Miller, D. R.

1978-01-01

Proposed highly reliable fault-tolerant reconfigurable digital control systems for a future generation of commercial aircraft consist of several k-out-of-n subsystems. Each of these flight-critical subsystems will consist of n identical components, k of which must be functioning properly in order for the aircraft to be dispatched. Failed components are recoverable; they are repaired in a shop. Spares are inventoried at a main base where they may be substituted for failed components on planes during layovers. Penalties are assessed when failure of a k-out-of-n subsystem causes a dispatch cancellation or delay. A maintenance model for a fleet of aircraft with such control systems is presented. The goals are to demonstrate economic feasibility and to optimize.

Myths and realities of electronics maintenance.

PubMed

Harris, Douglas H

2008-06-01

The author presents and discusses discoveries and developments contributing to enhanced electronics maintenance performance. This body of research is viewed from the vantage point of Nick Bond's 1970 Ely Award-winning article in Human Factors, "Some Persistent Myths About Military Electronics Maintenance." Bond identified a set of myths and summarized research that not only produced information and techniques leading to demonstrably improved maintenance performance but also exploded many unfounded beliefs that were commonly held before the research had been conducted and the findings disseminated. The period from 1964 through 1986, as reflected by publications in the journal, was a productive period of research that led to greater understanding of human factors in electronics maintenance and to numerous advances that contributed, ultimately, to more effective maintenance performance. Technological advances, combined with what we learned about maintenance performance, have substantially reduced the maintenance burden and enhanced the maintenance of electronic systems. Some of the principal lessons learned from this research on electronics maintenance apply to understanding the effects of equipment complexity, providing an optimal role for automation, designing more appropriate on-the-job training, and enhancing troubleshooting skills.

Dynamic decision-making for reliability and maintenance analysis of manufacturing systems based on failure effects

NASA Astrophysics Data System (ADS)

Zhang, Ding; Zhang, Yingjie

2017-09-01

A framework for reliability and maintenance analysis of job shop manufacturing systems is proposed in this paper. An efficient preventive maintenance (PM) policy in terms of failure effects analysis (FEA) is proposed. Subsequently, reliability evaluation and component importance measure based on FEA are performed under the PM policy. A job shop manufacturing system is applied to validate the reliability evaluation and dynamic maintenance policy. Obtained results are compared with existed methods and the effectiveness is validated. Some vague understandings for issues such as network modelling, vulnerabilities identification, the evaluation criteria of repairable systems, as well as PM policy during manufacturing system reliability analysis are elaborated. This framework can help for reliability optimisation and rational maintenance resources allocation of job shop manufacturing systems.

Evaluation of the Implementation of Operations and Maintenance Programs in New Jersey Schools.

ERIC Educational Resources Information Center

Kominsky, John R.; Freyberg, Ronald W.; Gerber, Donald R.; Centifonti, Gary J.

All schools are required to develop and implement an asbestos management plan (AMP). The key component of this plan is each school's operations and maintenance (O&M) program. This report outlines the importance of such programs. It describes an O&M program as an administrative framework that prescribes specific activities and work…

15 CFR 301.10 - Importation of repair components and maintenance tools under HTSUS subheadings 9810.00.65 and...

Code of Federal Regulations, 2011 CFR

2011-01-01

..., DEPARTMENT OF COMMERCE MISCELLANEOUS REGULATIONS INSTRUMENTS AND APPARATUS FOR EDUCATIONAL AND SCIENTIFIC... maintenance tools under HTSUS subheadings 9810.00.65 and 9810.00.67 for instruments previously the subject of... and 9810.00.67 for instruments previously the subject of an entry liquidated under subheading 9810.00...

15 CFR 301.10 - Importation of repair components and maintenance tools under HTSUS subheadings 9810.00.65 and...

Code of Federal Regulations, 2014 CFR

2014-01-01

..., DEPARTMENT OF COMMERCE MISCELLANEOUS REGULATIONS INSTRUMENTS AND APPARATUS FOR EDUCATIONAL AND SCIENTIFIC... maintenance tools under HTSUS subheadings 9810.00.65 and 9810.00.67 for instruments previously the subject of... and 9810.00.67 for instruments previously the subject of an entry liquidated under subheading 9810.00...

15 CFR 301.10 - Importation of repair components and maintenance tools under HTSUS subheadings 9810.00.65 and...

Code of Federal Regulations, 2012 CFR

2012-01-01

..., DEPARTMENT OF COMMERCE MISCELLANEOUS REGULATIONS INSTRUMENTS AND APPARATUS FOR EDUCATIONAL AND SCIENTIFIC... maintenance tools under HTSUS subheadings 9810.00.65 and 9810.00.67 for instruments previously the subject of... and 9810.00.67 for instruments previously the subject of an entry liquidated under subheading 9810.00...

15 CFR 301.10 - Importation of repair components and maintenance tools under HTSUS subheadings 9810.00.65 and...

Code of Federal Regulations, 2013 CFR

2013-01-01

..., DEPARTMENT OF COMMERCE MISCELLANEOUS REGULATIONS INSTRUMENTS AND APPARATUS FOR EDUCATIONAL AND SCIENTIFIC... maintenance tools under HTSUS subheadings 9810.00.65 and 9810.00.67 for instruments previously the subject of... and 9810.00.67 for instruments previously the subject of an entry liquidated under subheading 9810.00...

The ABPN Maintenance of Certification Program for Psychiatrists: Past History, Current Status, and Future Directions

ERIC Educational Resources Information Center

Faulkner, Larry R.; Tivnan, Patricia W.; Winstead, Daniel K.; Reus, Victor I.; Andrade, Naleen N.; Brooks, Beth Ann; Colenda, Christopher C.; Mrazek, David A.; Reifler, Burton V.; Schneidman, Barbara

2008-01-01

Objective: To describe the American Board of Psychiatry and Neurology (ABPN) Maintenance of Certification Program, its underlying rationale, how it will be implemented now, and what it might look like in the future. Methods: The authors describe the philosophical foundation, specific components, and the implementation timeline of the ABPN…

Korean Families in America: Their Family Language Policies and Home-Language Maintenance

ERIC Educational Resources Information Center

Kang, Hyun-Sook

2015-01-01

This study examined the family language policies (FLP) of Korean American parents and how the language practice, management, and ideology components of their FLP and demographic variables predict maintenance of the home language. Results of a large-scale (N = 480) survey show that different sets of FLP and demographic variables contributed to a…

30 CFR 250.516 - Blowout preventer system tests, inspections, and maintenance.

Code of Federal Regulations, 2011 CFR

2011-07-01

... marine riser at least once each day if weather and sea conditions permit. You may use television cameras... inspect a marine riser. (h) BOP maintenance. You must maintain your BOP system to ensure that the... components, and marine riser in the driller's report. In addition, you must: (1) Record BOP test pressures on...

Homeostatic Immunity and the Microbiota.

PubMed

Belkaid, Yasmine; Harrison, Oliver J

2017-04-18

The microbiota plays a fundamental role in the induction, education, and function of the host immune system. In return, the host immune system has evolved multiple means by which to maintain its symbiotic relationship with the microbiota. The maintenance of this dialogue allows the induction of protective responses to pathogens and the utilization of regulatory pathways involved in the sustained tolerance to innocuous antigens. The ability of microbes to set the immunological tone of tissues, both locally and systemically, requires tonic sensing of microbes and complex feedback loops between innate and adaptive components of the immune system. Here we review the dominant cellular mediators of these interactions and discuss emerging themes associated with our current understanding of the homeostatic immunological dialogue between the host and its microbiota. Published by Elsevier Inc.

Optical surface contouring for non-destructive inspection of turbomachinery

NASA Astrophysics Data System (ADS)

Modarress, Dariush; Schaack, David F.

1994-03-01

Detection of stress cracks and other surface defects during maintenance and in-service inspection of propulsion system components, including turbine blades and combustion compartments, is presently performed visually. There is a need for a non-contact, miniaturized, and fully fieldable instrument that may be used as an automated inspection tool for inspection of aircraft engines. During this SBIR Phase 1 program, the feasibility of a ruggedized optical probe for automatic and nondestructive inspection of complex shaped objects will be established. Through a careful analysis of the measurement requirements, geometrical and optical constraints, and consideration of issues such as manufacturability, compactness, simplicity, and cost, one or more conceptual optical designs will be developed. The proposed concept will be further developed and a prototype will be fabricated during Phase 2.

Homeostatic immunity and the microbiota

PubMed Central

Belkaid, Yasmine; Harrison, Oliver J.

2017-01-01

The microbiota plays a fundamental role in the induction, education and function of the host immune system. In return, the host immune system has evolved multiple means by which to maintain its symbiotic relationship with the microbiota. The maintenance of this dialogue allows the induction of protective responses to pathogens and the utilization of regulatory pathways involved in the sustained tolerance to innocuous antigens. The ability of microbes to set the immunological tone of tissues, both locally and systemically, requires tonic sensing of microbes and complex feedback loops between innate and adaptive components of the immune system. In this review, we will highlight the dominant cellular mediators of these interactions and discuss emerging themes associated with our current understanding of the homeostatic immunological dialogue between the host and its microbiota. PMID:28423337

Mitochondrial nucleoid interacting proteins support mitochondrial protein synthesis.

PubMed

He, J; Cooper, H M; Reyes, A; Di Re, M; Sembongi, H; Litwin, T R; Gao, J; Neuman, K C; Fearnley, I M; Spinazzola, A; Walker, J E; Holt, I J

2012-07-01

Mitochondrial ribosomes and translation factors co-purify with mitochondrial nucleoids of human cells, based on affinity protein purification of tagged mitochondrial DNA binding proteins. Among the most frequently identified proteins were ATAD3 and prohibitin, which have been identified previously as nucleoid components, using a variety of methods. Both proteins are demonstrated to be required for mitochondrial protein synthesis in human cultured cells, and the major binding partner of ATAD3 is the mitochondrial ribosome. Altered ATAD3 expression also perturbs mtDNA maintenance and replication. These findings suggest an intimate association between nucleoids and the machinery of protein synthesis in mitochondria. ATAD3 and prohibitin are tightly associated with the mitochondrial membranes and so we propose that they support nucleic acid complexes at the inner membrane of the mitochondrion.

Optical surface contouring for non-destructive inspection of turbomachinery

NASA Technical Reports Server (NTRS)

Modarress, Dariush; Schaack, David F.

1994-01-01

Detection of stress cracks and other surface defects during maintenance and in-service inspection of propulsion system components, including turbine blades and combustion compartments, is presently performed visually. There is a need for a non-contact, miniaturized, and fully fieldable instrument that may be used as an automated inspection tool for inspection of aircraft engines. During this SBIR Phase 1 program, the feasibility of a ruggedized optical probe for automatic and nondestructive inspection of complex shaped objects will be established. Through a careful analysis of the measurement requirements, geometrical and optical constraints, and consideration of issues such as manufacturability, compactness, simplicity, and cost, one or more conceptual optical designs will be developed. The proposed concept will be further developed and a prototype will be fabricated during Phase 2.

Cdc6 localizes to S- and G2-phase centrosomes in a cell cycle-dependent manner

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

Kim, Gwang Su; Kang, Jeeheon; Bang, Sung Woong

2015-01-16

Highlights: • Cdc6 protein is a component of the pre-replicative complex required for chromosomal replication initiation. • Cdc6 localized to centrosomes of S and G2 phases in a cell cycle-dependent manner. • The centrosomal localization was governed by centrosomal localization signal sequences of Cdc6. • Deletions or substitution mutations on the centrosomal localization signal interfered with centrosomal localization of the Cdc6 proteins. - Abstract: The Cdc6 protein has been primarily investigated as a component of the pre-replicative complex for the initiation of chromosome replication, which contributes to maintenance of chromosomal integrity. Here, we show that Cdc6 localized to the centrosomesmore » during S and G2 phases of the cell cycle. The centrosomal localization was mediated by Cdc6 amino acid residues 311–366, which are conserved within other Cdc6 homologues and contains a putative nuclear export signal. Deletions or substitutions of the amino acid residues did not allow the proteins to localize to centrosomes. In contrast, DsRed tag fused to the amino acid residues localized to centrosomes. These results indicated that a centrosome localization signal is contained within amino acid residues 311–366. The cell cycle-dependent centrosomal localization of Cdc6 in S and G2 phases suggest a novel function of Cdc6 in centrosomes.« less

Symmetric dimethylation of H3R2 is a newly identified histone mark that supports euchromatin maintenance.

PubMed

Migliori, Valentina; Müller, Julius; Phalke, Sameer; Low, Diana; Bezzi, Marco; Mok, Wei Chuen; Sahu, Sanjeeb Kumar; Gunaratne, Jayantha; Capasso, Paola; Bassi, Christian; Cecatiello, Valentina; De Marco, Ario; Blackstock, Walter; Kuznetsov, Vladimir; Amati, Bruno; Mapelli, Marina; Guccione, Ernesto

2012-01-08

The asymmetric dimethylation of histone H3 arginine 2 (H3R2me2a) acts as a repressive mark that antagonizes trimethylation of H3 lysine 4. Here we report that H3R2 is also symmetrically dimethylated (H3R2me2s) by PRMT5 and PRMT7 and present in euchromatic regions. Profiling of H3-tail interactors by SILAC MS revealed that H3R2me2s excludes binding of RBBP7, a central component of co-repressor complexes Sin3a, NURD and PRC2. Conversely H3R2me2s enhances binding of WDR5, a common component of the coactivator complexes MLL, SET1A, SET1B, NLS1 and ATAC. The interaction of histone H3 with WDR5 distinguishes H3R2me2s from H3R2me2a, which impedes the recruitment of WDR5 to chromatin. The crystallographic structure of WDR5 and the H3R2me2s peptide elucidates the molecular determinants of this high affinity interaction. Our findings identify H3R2me2s as a previously unknown mark that keeps genes poised in euchromatin for transcriptional activation upon cell-cycle withdrawal and differentiation in human cells.

40 CFR 1042.125 - Maintenance instructions.

Code of Federal Regulations, 2011 CFR

2011-07-01

... CONTROLS CONTROL OF EMISSIONS FROM NEW AND IN-USE MARINE COMPRESSION-IGNITION ENGINES AND VESSELS Emission... converters, electronic control units, particulate traps, trap oxidizers, components related to particulate..., electronic control units, particulate traps, trap oxidizers, components related to particulate traps and trap...

40 CFR 1042.125 - Maintenance instructions.

Code of Federal Regulations, 2013 CFR

2013-07-01

... CONTROLS CONTROL OF EMISSIONS FROM NEW AND IN-USE MARINE COMPRESSION-IGNITION ENGINES AND VESSELS Emission... converters, electronic control units, particulate traps, trap oxidizers, components related to particulate..., electronic control units, particulate traps, trap oxidizers, components related to particulate traps and trap...

40 CFR 1042.125 - Maintenance instructions.

Code of Federal Regulations, 2014 CFR

2014-07-01

... CONTROLS CONTROL OF EMISSIONS FROM NEW AND IN-USE MARINE COMPRESSION-IGNITION ENGINES AND VESSELS Emission... converters, electronic control units, particulate traps, trap oxidizers, components related to particulate..., electronic control units, particulate traps, trap oxidizers, components related to particulate traps and trap...

40 CFR 1042.125 - Maintenance instructions.

Code of Federal Regulations, 2012 CFR

2012-07-01

... CONTROLS CONTROL OF EMISSIONS FROM NEW AND IN-USE MARINE COMPRESSION-IGNITION ENGINES AND VESSELS Emission... converters, electronic control units, particulate traps, trap oxidizers, components related to particulate..., electronic control units, particulate traps, trap oxidizers, components related to particulate traps and trap...

Advanced Ground Systems Maintenance Prognostics Project

NASA Technical Reports Server (NTRS)

Harp, Janicce Leshay

2014-01-01

The project implements prognostics capabilities to predict when a component, system or subsystem will no longer meet desired functional or performance criteria, called the "end of life." The capability also provides an assessment of the "remaining useful life" of a hardware component.

Interventions for Weight Reduction: Facing the Maintenance Problem

ERIC Educational Resources Information Center

Anderson, Drew A.; Simmons, Angela M.; Milnes, Suzanne M.

2005-01-01

Behavioral treatments are perhaps the cornerstone of modern obesity treatment. Maintenance of weight lost via behavioral treatments has been less than hoped for, however. Weight regain is the result of complex interactions between physiological, behavioral, cognitive, and environmental factors; in this paper we review some of these factors and…

Two Maintenance Mechanisms of Verbal Information in Working Memory

ERIC Educational Resources Information Center

Camos, V.; Lagner, P.; Barrouillet, P.

2009-01-01

The present study evaluated the interplay between two mechanisms of maintenance of verbal information in working memory, namely articulatory rehearsal as described in Baddeley's model, and attentional refreshing as postulated in Barrouillet and Camos's Time-Based Resource-Sharing (TBRS) model. In four experiments using complex span paradigm, we…

Building Maintenance Syllabus.

ERIC Educational Resources Information Center

Fischer, Joseph; Messier, Joseph

Building maintenance is a basic two-year trade education course requiring 2 1/2 hours of study on each of 160 teaching days per year. Student abilities should range from those capable of the simplest custodial work to those who may eventually be superintendents of building complexes. The syllabus is organized in sections by traditional skills…

EAST ELEVATION OF MAIN PROCESSING BUILDING (CPP601) LOOKING NORTHWEST. MAINTENANCE ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

EAST ELEVATION OF MAIN PROCESSING BUILDING (CPP-601) LOOKING NORTHWEST. MAINTENANCE SHOP AND OFFICE BUILDING (CPP-630) ON RIGHT IN PHOTO. INL PHOTO NUMBER HD-22-3-2. Mike Crane, Photographer, 11/1998 - Idaho National Engineering Laboratory, Idaho Chemical Processing Plant, Fuel Reprocessing Complex, Scoville, Butte County, ID

39. Perimeter acquisition radar building room #504, techinal maintenance and ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

39. Perimeter acquisition radar building room #504, techinal maintenance and repair center (TMRC) and tactical support equipment (TSE) storage area; storage-travel wave tubes - Stanley R. Mickelsen Safeguard Complex, Perimeter Acquisition Radar Building, Limited Access Area, between Limited Access Patrol Road & Service Road A, Nekoma, Cavalier County, ND

Cryogenics maintenance strategy

NASA Astrophysics Data System (ADS)

Cruzat, Fabiola

2012-09-01

ALMA is an interferometer composed of 66 independent systems, with specific maintenance requirements for each subsystem. To optimize the observation time and reduce downtime maintenance, requirements are very demanding. One subsystem with high maintenance efforts is cryogenics and vacuum. To organize the maintenance, the Cryogenic and Vacuum department is using and implementing different tools. These are monitoring and problem reporting systems and CMMS. This leads to different maintenance approaches: Preventive Maintenance, Corrective Maintenance and Condition Based Maintenance. In order to coordinate activities with other departments the preventive maintenance schedule is kept as flexible as systems allow. To cope with unavoidable failures, the team has to be prepared to work under any condition with the spares on time. Computerized maintenance management system (CMMS) will help to manage inventory control for reliable spare part handling, the correct record of work orders and traceability of maintenance activities. For an optimized approach the department is currently evaluating where preventive or condition based maintenance applies to comply with the individual system demand. Considering the change from maintenance contracts to in-house maintenance will help to minimize costs and increase availability of parts. Due to increased number of system and tasks the cryo team needs to grow. Training of all staff members is mandatory, in depth knowledge must be built up by doing complex maintenance activities in the Cryo group, use of advanced computerized metrology systems.

Using a system of differential equations that models cattle growth to uncover the genetic basis of complex traits.

PubMed

Freua, Mateus Castelani; Santana, Miguel Henrique de Almeida; Ventura, Ricardo Vieira; Tedeschi, Luis Orlindo; Ferraz, José Bento Sterman

2017-08-01

The interplay between dynamic models of biological systems and genomics is based on the assumption that genetic variation of the complex trait (i.e., outcome of model behavior) arises from component traits (i.e., model parameters) in lower hierarchical levels. In order to provide a proof of concept of this statement for a cattle growth model, we ask whether model parameters map genomic regions that harbor quantitative trait loci (QTLs) already described for the complex trait. We conducted a genome-wide association study (GWAS) with a Bayesian hierarchical LASSO method in two parameters of the Davis Growth Model, a system of three ordinary differential equations describing DNA accretion, protein synthesis and degradation, and fat synthesis. Phenotypic and genotypic data were available for 893 Nellore (Bos indicus) cattle. Computed values for parameter k 1 (DNA accretion rate) ranged from 0.005 ± 0.003 and for α (constant for energy for maintenance requirement) 0.134 ± 0.024. The expected biological interpretation of the parameters is confirmed by QTLs mapped for k 1 and α. QTLs within genomic regions mapped for k 1 are expected to be correlated with the DNA pool: body size and weight. Single nucleotide polymorphisms (SNPs) which were significant for α mapped QTLs that had already been associated with residual feed intake, feed conversion ratio, average daily gain (ADG), body weight, and also dry matter intake. SNPs identified for k 1 were able to additionally explain 2.2% of the phenotypic variability of the complex ADG, even when SNPs for k 1 did not match the genomic regions associated with ADG. Although improvements are needed, our findings suggest that genomic analysis on component traits may help to uncover the genetic basis of more complex traits, particularly when lower biological hierarchies are mechanistically described by mathematical simulation models.

Advancing complex explanatory conceptualizations of daily negative and positive affect: trigger and maintenance coping action patterns.

PubMed

Dunkley, David M; Ma, Denise; Lee, Ihno A; Preacher, Kristopher J; Zuroff, David C

2014-01-01

The present study addressed a fundamental gap between research and clinical work by advancing complex explanatory conceptualizations of coping action patterns that trigger and maintain daily negative affect and (low) positive affect. One hundred ninety-six community adults completed measures of perfectionism, and then 6 months later completed questionnaires at the end of the day for 14 consecutive days to provide simultaneous assessments of appraisals, coping, and affect across different stressful situations in everyday life. Multilevel structural equation modeling (MSEM) supported complex explanatory conceptualizations that demonstrated (a) disengagement trigger patterns consisting of several distinct appraisals (e.g., event stress) and coping strategies (e.g., avoidant coping) that commonly operate together across many different stressors when the typical individual experiences daily increases in negative affect and drops in positive affect; and (b) disengagement maintenance patterns composed of different appraisal and coping maintenance factors that, in combination, can explain why individuals with higher levels of self-critical perfectionism have persistent daily negative affect and low positive mood 6 months later. In parallel, engagement patterns (triggers and maintenance) composed of distinct appraisals (e.g., perceived social support) and coping strategies (e.g., problem-focused coping) were linked to compensatory experiences of daily positive affect. These findings demonstrate the promise of using daily diary methodologies and MSEM to promote a shared understanding between therapists and clients of trigger and maintenance coping action patterns that explain what precipitates and perpetuates clients' difficulties, which, in turn, can help achieve the 2 overarching therapy goals of reducing clients' distress and bolstering resilience. (c) 2014 APA, all rights reserved.

A theoretical reassessment of microbial maintenance and implications for microbial ecology modeling.

PubMed

Wang, Gangsheng; Post, Wilfred M

2012-09-01

We attempted to reconcile three microbial maintenance models (Herbert, Pirt, and Compromise) through a theoretical reassessment. We provided a rigorous proof that the true growth yield coefficient (Y(G)) is the ratio of the specific maintenance rate (a in Herbert) to the maintenance coefficient (m in Pirt). Other findings from this study include: (1) the Compromise model is identical to the Herbert for computing microbial growth and substrate consumption, but it expresses the dependence of maintenance on both microbial biomass and substrate; (2) the maximum specific growth rate in the Herbert (μ(max,H)) is higher than those in the other two models (μ(max,P) and μ(max,C)), and the difference is the physiological maintenance factor (m(q) = a); and (3) the overall maintenance coefficient (m(T)) is more sensitive to m(q) than to the specific growth rate (μ(G)) and Y(G). Our critical reassessment of microbial maintenance provides a new approach for quantifying some important components in soil microbial ecology models. © This article is a US government work and is in the public domain in the USA.

Flight control electronics reliability/maintenance study

NASA Technical Reports Server (NTRS)

Dade, W. W.; Edwards, R. H.; Katt, G. T.; Mcclellan, K. L.; Shomber, H. A.

1977-01-01

Collection and analysis of data are reported that concern the reliability and maintenance experience of flight control system electronics currently in use on passenger carrying jet aircraft. Two airlines B-747 airplane fleets were analyzed to assess the component reliability, system functional reliability, and achieved availability of the CAT II configuration flight control system. Also assessed were the costs generated by this system in the categories of spare equipment, schedule irregularity, and line and shop maintenance. The results indicate that although there is a marked difference in the geographic location and route pattern between the airlines studied, there is a close similarity in the reliability and the maintenance costs associated with the flight control electronics.

COMCAN; COMCAN2A; system safety common cause analysis. [IBM360; CDC CYBER176,175; FORTRAN IV (30%) and BAL (70%) (IBM360), FORTRAN IV (97%) and COMPASS (3%) (CDC CYBER176)

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

Burdick, G.R.; Wilson, J.R.

COMCAN2A and COMCAN are designed to analyze complex systems such as nuclear plants for common causes of failure. A common cause event, or common mode failure, is a secondary cause that could contribute to the failure of more than one component and violates the assumption of independence. Analysis of such events is an integral part of system reliability and safety analysis. A significant common cause event is a secondary cause common to all basic events in one or more minimal cut sets. Minimal cut sets containing events from components sharing a common location or a common link are called commonmore » cause candidates. Components share a common location if no barrier insulates any one of them from the secondary cause. A common link is a dependency among components which cannot be removed by a physical barrier (e.g., a common energy source or common maintenance instructions).IBM360;CDC CYBER176,175; FORTRAN IV (30%) and BAL (70%) (IBM360), FORTRAN IV (97%) and COMPASS (3%) (CDC CYBER176).; OS/360 (IBM360) and NOS/BE 1.4 (CDC CYBER176), NOS 1.3 (CDC CYBER175); 140K bytes of memory for COMCAN and 242K (octal) words of memory for COMCAN2A.« less

Relocation of the Deep Space Network Maintenance Center

NASA Technical Reports Server (NTRS)

Beutler, K. F.

1981-01-01

The Jet Propulsion Laboratory maintains a Deep Space Network (DSN) maintenance center (DMC), whose task is to engineer and manage the repair and calibration program for the electronic and mechanical equipment used in the tracking stations located at Madrid, Spain, and Canberra, Australia. The DMC also manages the Goldstone complex maintenance facility (GCMF), whose task is to repair and calibrate the Goldstone electronic and mechanical equipment. The rationale for moving the facility to Barstow, California, and the benefits derived from the move are discussed.

Two-component signal transduction systems of Xanthomonas spp.: a lesson from genomics.

PubMed

Qian, Wei; Han, Zhong-Ji; He, Chaozu

2008-02-01

The two-component signal transduction systems (TCSTSs), consisting of a histidine kinase sensor (HK) and a response regulator (RR), are the dominant molecular mechanisms by which prokaryotes sense and respond to environmental stimuli. Genomes of Xanthomonas generally contain a large repertoire of TCSTS genes (approximately 92 to 121 for each genome), which encode diverse structural groups of HKs and RRs. Among them, although a core set of 70 TCSTS genes (about two-thirds in total) which accumulates point mutations with a slow rate are shared by these genomes, the other genes, especially hybrid HKs, experienced extensive genetic recombination, including genomic rearrangement, gene duplication, addition or deletion, and fusion or fission. The recombinations potentially promote the efficiency and complexity of TCSTSs in regulating gene expression. In addition, our analysis suggests that a co-evolutionary model, rather than a selfish operon model, is the major mechanism for the maintenance and microevolution of TCSTS genes in the genomes of Xanthomonas. Genomic annotation, secondary protein structure prediction, and comparative genomic analyses of TCSTS genes reviewed here provide insights into our understanding of signal networks in these important phytopathogenic bacteria.

Wnt6 maintains anterior escort cells as an integral component of the germline stem cell niche

PubMed Central

2018-01-01

ABSTRACT Stem cells reside in a niche, a local environment whose cellular and molecular complexity is still being elucidated. In Drosophila ovaries, germline stem cells depend on cap cells for self-renewing signals and physical attachment. Germline stem cells also contact the anterior escort cells, and here we report that anterior escort cells are absolutely required for germline stem cell maintenance. When escort cells die from impaired Wnt signaling or hid expression, the loss of anterior escort cells causes loss of germline stem cells. Anterior escort cells function as an integral niche component by promoting DE-cadherin anchorage and by transiently expressing the Dpp ligand to promote full-strength BMP signaling in germline stem cells. Anterior escort cells are maintained by Wnt6 ligands produced by cap cells; without Wnt6 signaling, anterior escort cells die leaving vacancies in the niche, leading to loss of germline stem cells. Our data identify anterior escort cells as constituents of the germline stem cell niche, maintained by a cap cell-produced Wnt6 survival signal. PMID:29361569

Wnt6 maintains anterior escort cells as an integral component of the germline stem cell niche.

PubMed

Wang, Xiaoxi; Page-McCaw, Andrea

2018-02-07

Stem cells reside in a niche, a local environment whose cellular and molecular complexity is still being elucidated. In Drosophila ovaries, germline stem cells depend on cap cells for self-renewing signals and physical attachment. Germline stem cells also contact the anterior escort cells, and here we report that anterior escort cells are absolutely required for germline stem cell maintenance. When escort cells die from impaired Wnt signaling or hid expression, the loss of anterior escort cells causes loss of germline stem cells. Anterior escort cells function as an integral niche component by promoting DE-cadherin anchorage and by transiently expressing the Dpp ligand to promote full-strength BMP signaling in germline stem cells. Anterior escort cells are maintained by Wnt6 ligands produced by cap cells; without Wnt6 signaling, anterior escort cells die leaving vacancies in the niche, leading to loss of germline stem cells. Our data identify anterior escort cells as constituents of the germline stem cell niche, maintained by a cap cell-produced Wnt6 survival signal. © 2018. Published by The Company of Biologists Ltd.

AUTOMOTIVE DIESEL MAINTENANCE 2. UNIT XII, LEARNING ABOUT BATTERY SERVICING AND TESTING (PART I).

ERIC Educational Resources Information Center

Human Engineering Inst., Cleveland, OH.

THID MODULE OF A 25-MODULE COURSE IS DESIGNED TO DEVELOP AN UNDERSTANDING OF THE CONSTRUCTION AND MAINTENANCE OF LEAD-ACID STORAGE BATTERIES USED ON DIESEL POWERED EQUIPMENT. TOPICS ARE (1) BATTERY COMPONENTS AND CONSTRUCTION, (2) CHEMICAL ACTION IN BATTERIES, (3) THE BATTERY AND THE CHARGING CIRCUIT, (4) BATTERY CHARGING VOLTAGE, (5) EFFECTS OF…

Perceptual/Psychomotor Requirements Basic to performance in 35 Air Force Specialties.

DTIC Science & Technology

1980-12-01

Supra-segmental Reflexes c 26. Locomotor Movements¢ 27. Non- Locomotor Movementac 28. Manipulative Movements c 29. Kinesthetic Discrimination 30...auxiliary equipment components for installation (6.10, Ground Radio Equipment Repair) Control Operate standard gasoline or electric powered forklifts...Precision (6.23, Munitions Maintenance) Operate munitions transport trucks or truck-tractors (6.19, Munitions Maintenance) Rate operate standard gasoline or

Mi-2/NuRD complex function is required for normal S phase progression and assembly of pericentric heterochromatin.

PubMed

Sims, Jennifer K; Wade, Paul A

2011-09-01

During chromosome duplication, it is essential to replicate not only the DNA sequence, but also the complex nucleoprotein structures of chromatin. Pericentric heterochromatin is critical for silencing repetitive elements and plays an essential structural role during mitosis. However, relatively little is understood about its assembly and maintenance during replication. The Mi2/NuRD chromatin remodeling complex tightly associates with actively replicating pericentric heterochromatin, suggesting a role in its assembly. Here we demonstrate that depletion of the catalytic ATPase subunit CHD4/Mi-2β in cells with a dampened DNA damage response results in a slow-growth phenotype characterized by delayed progression through S phase. Furthermore, we observe defects in pericentric heterochromatin maintenance and assembly. Our data suggest that chromatin assembly defects are sensed by an ATM-dependent intra-S phase chromatin quality checkpoint, resulting in a temporal block to the transition from early to late S phase. These findings implicate Mi-2β in the maintenance of chromatin structure and proper cell cycle progression.

Aconitase couples metabolic regulation to mitochondrial DNA maintenance.

PubMed

Chen, Xin Jie; Wang, Xiaowen; Kaufman, Brett A; Butow, Ronald A

2005-02-04

Mitochondrial DNA (mtDNA) is essential for cells to maintain respiratory competency and is inherited as a protein-DNA complex called the nucleoid. We have identified 22 mtDNA-associated proteins in yeast, among which is mitochondrial aconitase (Aco1p). We show that this Krebs-cycle enzyme is essential for mtDNA maintenance independent of its catalytic activity. Regulation of ACO1 expression by the HAP and retrograde metabolic signaling pathways directly affects mtDNA maintenance. When constitutively expressed, Aco1p can replace the mtDNA packaging function of the high-mobility-group protein Abf2p. Thus, Aco1p may integrate metabolic signals and mtDNA maintenance.

Developing a comprehensive training curriculum for integrated predictive maintenance

NASA Astrophysics Data System (ADS)

Wurzbach, Richard N.

2002-03-01

On-line equipment condition monitoring is a critical component of the world-class production and safety histories of many successful nuclear plant operators. From addressing availability and operability concerns of nuclear safety-related equipment to increasing profitability through support system reliability and reduced maintenance costs, Predictive Maintenance programs have increasingly become a vital contribution to the maintenance and operation decisions of nuclear facilities. In recent years, significant advancements have been made in the quality and portability of many of the instruments being used, and software improvements have been made as well. However, the single most influential component of the success of these programs is the impact of a trained and experienced team of personnel putting this technology to work. Changes in the nature of the power generation industry brought on by competition, mergers, and acquisitions, has taken the historically stable personnel environment of power generation and created a very dynamic situation. As a result, many facilities have seen a significant turnover in personnel in key positions, including predictive maintenance personnel. It has become the challenge for many nuclear operators to maintain the consistent contribution of quality data and information from predictive maintenance that has become important in the overall equipment decision process. These challenges can be met through the implementation of quality training to predictive maintenance personnel and regular updating and re-certification of key technology holders. The use of data management tools and services aid in the sharing of information across sites within an operating company, and with experts who can contribute value-added data management and analysis. The overall effectiveness of predictive maintenance programs can be improved through the incorporation of newly developed comprehensive technology training courses. These courses address the use of key technologies such as vibration analysis, infrared thermography, and oil analysis not as singular entities, but as a toolbox resource from which to address overall equipment and plant reliability in a structured program and decision environment.

Literacy Audit of Maintenance Workers. Final Report.

ERIC Educational Resources Information Center

Gold, Patricia; Packer, Arnold

An 18-month national literacy audit of maintenance worker jobs in multifamily apartment complexes sought to find out: (1) the literacy demands for their job success and promotion; (2) the effects of geographical location on their literacy demands; (3) the effects of management policies on their literacy demands; (4) the impact of illiteracy on…

78 FR 73794 - Taking and Importing Marine Mammals; Taking Marine Mammals Incidental to U.S. Air Force Launches...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-12-09

... operations from VAFB launch complexes and Delta Mariner operations, cargo unloading activities, and harbor maintenance dredging in support of the Delta IV/Evolved Expendable Launch Vehicle (EELV) launch activity on... Delta Mariner operations, cargo unloading activities, and harbor maintenance dredging. The Delta Mariner...

115. QUALITY CONTROL BOARD FOR MAINTENANCE AND INSPECTION AT SOUTH ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

115. QUALITY CONTROL BOARD FOR MAINTENANCE AND INSPECTION AT SOUTH SIDE OF MECHANICAL AND ELECTRICAL ROOM (110), LSB (BLDG. 770), FACING WEST ON EXTERIOR WALL OF QUALITY ASSURANCE ROOM (106A) - Vandenberg Air Force Base, Space Launch Complex 3, Launch Pad 3 West, Napa & Alden Roads, Lompoc, Santa Barbara County, CA

76 FR 16842 - Request for a License To Export Reactor Components

Federal Register 2010, 2011, 2012, 2013, 2014

2011-03-25

... NUCLEAR REGULATORY COMMISSION Request for a License To Export Reactor Components Pursuant to 10.... Mechanical Corporation. coolant pump 1000 (design) maintenance, and systems, related reactors. operation of AP- equipment, and 1000 (design) spare parts. nuclear reactors. February 10, 2011 February 23, 2011...

14 CFR 43.2 - Records of overhaul and rebuilding.

Code of Federal Regulations, 2014 CFR

2014-01-01

... engine, propeller, appliance, or component part as being overhauled unless— (1) Using methods, techniques... may describe in any required maintenance entry or form an aircraft, airframe, aircraft engine, propeller, appliance, or component part as being rebuilt unless it has been disassembled, cleaned, inspected...

14 CFR 43.2 - Records of overhaul and rebuilding.

Code of Federal Regulations, 2013 CFR

2013-01-01

... engine, propeller, appliance, or component part as being overhauled unless— (1) Using methods, techniques... may describe in any required maintenance entry or form an aircraft, airframe, aircraft engine, propeller, appliance, or component part as being rebuilt unless it has been disassembled, cleaned, inspected...

14 CFR 43.2 - Records of overhaul and rebuilding.

Code of Federal Regulations, 2012 CFR

2012-01-01

... engine, propeller, appliance, or component part as being overhauled unless— (1) Using methods, techniques... may describe in any required maintenance entry or form an aircraft, airframe, aircraft engine, propeller, appliance, or component part as being rebuilt unless it has been disassembled, cleaned, inspected...

Practical experience with the maintenance and auditing of a large medical ontology.

PubMed

Baorto, David; Li, Li; Cimino, James J

2009-06-01

The Medical Entities Dictionary (MED) has served as a unified terminology at New York Presbyterian Hospital and Columbia University for more than 20 years. It was initially created to allow the clinical data from the disparate information systems (e.g., radiology, pharmacy, and multiple laboratories, etc.) to be uniquely codified for storage in a single data repository, and functions as a real time terminology server for clinical applications and decision support tools. Being conceived as a knowledge base, the MED incorporates relationships among local terms, between local terms and external standards, and additional knowledge about terms in a semantic network structure. Over the past two decades, we have sought to develop methods to maintain, audit and improve the content of the MED, such that it remains true to its original design goals. This has resulted in a complex, multi-faceted process, with both manual and automated components. In this paper, we describe this process, with examples of its effectiveness. We believe that our process provides lessons for others who seek to maintain complex, concept-oriented controlled terminologies.

Practical Experience with the Maintenance and Auditing of a Large Medical Ontology

PubMed Central

Baorto, David; Li, Li; Cimino, James J.

2012-01-01

The Medical Entities Dictionary (MED) has served as a unified terminology at New York Presbyterian Hospital and Columbia University for more than 20 years. It was initially created to allow the clinical data from the disparate information systems (e.g., radiology, pharmacy, and multiple laboratories, etc) to be uniquely codified for storage in a single data repository, and functions as a real time terminology server for clinical applications and decision support tools. Being conceived as a knowledge base, the MED incorporates relationships among local terms, between local terms and external standards, and additional knowledge about terms in a semantic network structure. Over the past two decades, we have sought to develop methods to maintain, audit and improve the content of the MED, such that it remains true to its original design goals. This has resulted in a complex, multi-faceted process, with both manual and automated components. In this paper, we describe this process, with examples of its effectiveness. We believe that our process provides lessons for others who seek to maintain complex, concept-oriented controlled terminologies. PMID:19285569

Mitochondrial Nucleoid: Shield and Switch of the Mitochondrial Genome

PubMed Central

2017-01-01

Mitochondria preserve very complex and distinctively unique machinery to maintain and express the content of mitochondrial DNA (mtDNA). Similar to chromosomes, mtDNA is packaged into discrete mtDNA-protein complexes referred to as a nucleoid. In addition to its role as a mtDNA shield, over 50 nucleoid-associated proteins play roles in mtDNA maintenance and gene expression through either temporary or permanent association with mtDNA or other nucleoid-associated proteins. The number of mtDNA(s) contained within a single nucleoid is a fundamental question but remains a somewhat controversial issue. Disturbance in nucleoid components and mutations in mtDNA were identified as significant in various diseases, including carcinogenesis. Significant interest in the nucleoid structure and its regulation has been stimulated in relation to mitochondrial diseases, which encompass diseases in multicellular organisms and are associated with accumulation of numerous mutations in mtDNA. In this review, mitochondrial nucleoid structure, nucleoid-associated proteins, and their regulatory roles in mitochondrial metabolism are briefly addressed to provide an overview of the emerging research field involving mitochondrial biology. PMID:28680532

The actin family protein ARP6 contributes to the structure and the function of the nucleolus.

PubMed

Kitamura, Hiroshi; Matsumori, Haruka; Kalendova, Alzbeta; Hozak, Pavel; Goldberg, Ilya G; Nakao, Mitsuyoshi; Saitoh, Noriko; Harata, Masahiko

2015-08-21

The actin family members, consisting of actin and actin-related proteins (ARPs), are essential components of chromatin remodeling complexes. ARP6, one of the nuclear ARPs, is part of the Snf-2-related CREB-binding protein activator protein (SRCAP) chromatin remodeling complex, which promotes the deposition of the histone variant H2A.Z into the chromatin. In this study, we showed that ARP6 influences the structure and the function of the nucleolus. ARP6 is localized in the central region of the nucleolus, and its knockdown induced a morphological change in the nucleolus. We also found that in the presence of high concentrations of glucose ARP6 contributed to the maintenance of active ribosomal DNA (rDNA) transcription by placing H2A.Z into the chromatin. In contrast, under starvation, ARP6 was required for cell survival through the repression of rDNA transcription independently of H2A.Z. These findings reveal novel pleiotropic roles for the actin family in nuclear organization and metabolic homeostasis. Copyright © 2015 Elsevier Inc. All rights reserved.

The actin family protein ARP6 contributes to the structure and the function of the nucleolus

PubMed Central

Kitamura, Hiroshi; Matsumori, Haruka; Kalendova, Alzbeta; Hozak, Pavel; Goldberg, Ilya G.; Nakao, Mitsuyoshi; Saitoh, Noriko; Harata, Masahiko

2018-01-01

The actin family members, consisting of actin and actin-related proteins (ARPs), are essential components of chromatin remodeling complexes. ARP6, one of the nuclear ARPs, is part of the Snf-2-related CREB-binding protein activator protein (SRCAP) chromatin remodeling complex, which promotes the deposition of the histone variant H2A.Z into the chromatin. In this study, we showed that ARP6 influences the structure and the function of the nucleolus. ARP6 is localized in the central region of the nucleolus, and its knockdown induced a morphological change in the nucleolus. We also found that in the presence of high concentrations of glucose ARP6 contributed to the maintenance of active ribosomal DNA (rDNA) transcription by placing H2A.Z into the chromatin. In contrast, under starvation, ARP6 was required for cell survival through the repression of rDNA transcription independently of H2A.Z. These findings reveal novel pleiotropic roles for the actin family in nuclear organization and metabolic homeostasis. PMID:26164235

Ultrafast creation of large Schrödinger cat states of an atom.

PubMed

Johnson, K G; Wong-Campos, J D; Neyenhuis, B; Mizrahi, J; Monroe, C

2017-09-26

Mesoscopic quantum superpositions, or Schrödinger cat states, are widely studied for fundamental investigations of quantum measurement and decoherence as well as applications in sensing and quantum information science. The generation and maintenance of such states relies upon a balance between efficient external coherent control of the system and sufficient isolation from the environment. Here we create a variety of cat states of a single trapped atom's motion in a harmonic oscillator using ultrafast laser pulses. These pulses produce high fidelity impulsive forces that separate the atom into widely separated positions, without restrictions that typically limit the speed of the interaction or the size and complexity of the resulting motional superposition. This allows us to quickly generate and measure cat states larger than previously achieved in a harmonic oscillator, and create complex multi-component superposition states in atoms.Generation of mesoscopic quantum superpositions requires both reliable coherent control and isolation from the environment. Here, the authors succeed in creating a variety of cat states of a single trapped atom, mapping spin superpositions into spatial superpositions using ultrafast laser pulses.

Multiple Shh signaling centers participate in fungiform papilla and taste bud formation and maintenance

PubMed Central

Liu, H-X; Ermilov, A; Grachtchouk, M; Li, L; Gumucio, DL; Dlugosz, AA; Mistretta, CM

2014-01-01

The adult fungiform taste papilla is a complex of specialized cell types residing in the stratified squamous tongue epithelium. This unique sensory organ includes taste buds, papilla epithelium and lateral walls that extend into underlying connective tissue to surround a core of lamina propria cells. Fungiform papillae must contain long-lived, sustaining or stem cells and short-lived, maintaining or transit amplifying cells that support the papilla and specialized taste buds. Shh signaling has established roles in supporting fungiform induction, development and patterning. However, for a full understanding of how Shh transduced signals act in tongue, papilla and taste bud formation and maintenance, it is necessary to know where and when the Shh ligand and pathway components are positioned. We used immunostaining, in situ hybridization and mouse reporter strains for Shh, Ptch1, Gli1 and Gli2-expression and proliferation markers to identify cells that participate in hedgehog signaling. Whereas there is a progressive restriction in location of Shh ligand-expressing cells, from placode and apical papilla cells to taste bud cells only, a surrounding population of Ptch1 and Gli1 responding cells is maintained in signaling centers throughout papilla and taste bud development and differentiation. The Shh signaling targets are in regions of active cell proliferation. Using genetic-inducible lineage tracing for Gli1-expression, we found that Shh-responding cells contribute not only to maintenance of filiform and fungiform papillae, but also to taste buds. A requirement for normal Shh signaling in fungiform papilla, taste bud and filiform papilla maintenance was shown by Gli2 constitutive activation. We identified proliferation niches where Shh signaling is active and suggest that epithelial and mesenchymal compartments harbor potential stem and/or progenitor cell zones. In all, we report a set of hedgehog signaling centers that regulate development and maintenance of taste organs, the fungiform papilla and taste bud, and surrounding lingual cells. Shh signaling has roles in forming and maintaining fungiform papillae and taste buds, most likely via stage-specific autocrine and/or paracrine mechanisms, and by engaging epithelial/mesenchymal interactions. PMID:23916850

Multiple Shh signaling centers participate in fungiform papilla and taste bud formation and maintenance.

PubMed

Liu, Hong Xiang; Ermilov, Alexandre; Grachtchouk, Marina; Li, Libo; Gumucio, Deborah L; Dlugosz, Andrzej A; Mistretta, Charalotte M

2013-10-01

The adult fungiform taste papilla is a complex of specialized cell types residing in the stratified squamous tongue epithelium. This unique sensory organ includes taste buds, papilla epithelium and lateral walls that extend into underlying connective tissue to surround a core of lamina propria cells. Fungiform papillae must contain long-lived, sustaining or stem cells and short-lived, maintaining or transit amplifying cells that support the papilla and specialized taste buds. Shh signaling has established roles in supporting fungiform induction, development and patterning. However, for a full understanding of how Shh transduced signals act in tongue, papilla and taste bud formation and maintenance, it is necessary to know where and when the Shh ligand and pathway components are positioned. We used immunostaining, in situ hybridization and mouse reporter strains for Shh, Ptch1, Gli1 and Gli2-expression and proliferation markers to identify cells that participate in hedgehog signaling. Whereas there is a progressive restriction in location of Shh ligand-expressing cells, from placode and apical papilla cells to taste bud cells only, a surrounding population of Ptch1 and Gli1 responding cells is maintained in signaling centers throughout papilla and taste bud development and differentiation. The Shh signaling targets are in regions of active cell proliferation. Using genetic-inducible lineage tracing for Gli1-expression, we found that Shh-responding cells contribute not only to maintenance of filiform and fungiform papillae, but also to taste buds. A requirement for normal Shh signaling in fungiform papilla, taste bud and filiform papilla maintenance was shown by Gli2 constitutive activation. We identified proliferation niches where Shh signaling is active and suggest that epithelial and mesenchymal compartments harbor potential stem and/or progenitor cell zones. In all, we report a set of hedgehog signaling centers that regulate development and maintenance of taste organs, the fungiform papilla and taste bud, and surrounding lingual cells. Shh signaling has roles in forming and maintaining fungiform papillae and taste buds, most likely via stage-specific autocrine and/or paracrine mechanisms, and by engaging epithelial/mesenchymal interactions. © 2013 Elsevier Inc. All rights reserved.

RECOVERY ACT - Thylakoid Assembly and Folded Protein Transport by the Tat Pathway

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

Dabney-Smith, Carole

Assembly of functional photosystems complete with necessary intrinsic (membrane-bound) and extrinsic proteins requires the function of at least 3 protein transport pathways in thylakoid membranes. Our research focuses on one of those pathways, a unique and essential protein transport pathway found in the chloroplasts of plants, bacteria, and some archaebacteria, the Twin arginine translocation (Tat) system. The chloroplast Tat (cpTat) system is thought to be responsible for the proper location of ~50% of thylakoid lumen proteins, several of which are necessary for proper photosystem assembly, maintenance, and function. Specifically, cpTat systems are unique because they transport fully folded and assembledmore » proteins across ion tight membranes using only three membrane components, Tha4, Hcf106, and cpTatC, and the protonmotive force generated by photosynthesis. Despite the importance of the cpTat system in plants, the mechanism of transport of a folded precursor is not well known. Our long-term goal is to investigate the role protein transport systems have on organelle biogenesis, particularly the assembly of membrane protein complexes in thylakoids of chloroplasts. The objective of this proposal is to correlate structural changes in the membrane-bound cpTat component, Tha4, to the mechanism of translocation of folded-precursor substrates across the membrane bilayer by using a cysteine accessibility and crosslinking approach. Our central hypothesis is that the precursor passes through a proteinaceous pore of assembled Tha4 protomers that have undergone a conformational or topological change in response to transport. This research is predicated upon the observations that Tha4 exists in molar excess in the membrane relative to the other cpTat components; its regulated assembly to the precursor-bound receptor; and our data showing oligomerization of Tha4 into very large complexes in response to transport. Our rationale for these studies is that understanding cpTat system mechanism in chloroplasts will lead to a better understanding of the biogenesis of photosynthetic membranes potentially providing a means to engineer photosynthetic complexes into synthetic membranes for energy production. We are especially well prepared to undertake this project because we have developed a novel functional replacement assay, which was used to demonstrate a correlation of Tha4 oligomerization to transport. Thylakoids of plant chloroplasts provide a very robust, reliable assay to gain mechanistic detail about cpTat systems, providing most of the biochemical analyses to date. We plan to test our central hypothesis and accomplish the overall objective of this proposal by (1) Identifying the cpTat component(s) that interact with the mature domain of precursor during transport, (2) Determining the organization of the cpTat translocon, and (3) Comparing Tha4 topology in thylakoids during active transport and at rest. The proposed studies are innovative due to our ability to correlate structural changes in cpTat protein complexes during the transport of precursor. At the completion of this project, we expect to know the cpTat component(s) that interacts directly with the mature domain of the precursor, important because it is not known which components comprise the pore for passage of the mature domain. We also expect to know the arrangement of the components in the cpTat transport complex through direct interaction between Tha4 and the other CpTat components, a key point to establishing the mechanism of translocation. Lastly, we expect to correlate topological changes of Tha4 with precursor transport, key to establishing Tha4's role in the transport process. The successful completion of these studies is expected to have an important impact in understanding chloroplast biogenesis and assembly of photosynthetic complexes in plants and photosynthetic bacteria.« less

The roles of body mass and gravity in determining the energy requirements of homoiotherms

NASA Technical Reports Server (NTRS)

Smith, A. H.

1977-01-01

Studies by Kleiber and by Brody in the 1930's established the 3/4 power of body weight as the unit of metabolic size for homoiotherms. Later Kleiber conceived of the energy requirement as a composite function, with a thermoregulatory component that is proportional to heat loss, and an antigravity component that is directly proportional to body weight. Maintenance feed requirements (F) have been measured with groups of small animals chronically exposed to several acceleration fields (G). Analysis of the results leads to an arithmetic relationship between the maintenance requirement and acceleration field strength: F sub G = F sub 0 + kG. When the equations are compared for groups of different body size, F sub 0 tends to vary between the 0.4 and 0.5 power of body mass - and k tends to be the same, irrespective of body mass. These findings tend to confirm the Kleiber concept of a composite nature of homoiotherm maintenance requirements.

Value of information of repair times for offshore wind farm maintenance planning

NASA Astrophysics Data System (ADS)

Seyr, Helene; Muskulus, Michael

2016-09-01

A large contribution to the total cost of energy in offshore wind farms is due to maintenance costs. In recent years research has focused therefore on lowering the maintenance costs using different approaches. Decision support models for scheduling the maintenance exist already, dealing with different factors influencing the scheduling. Our contribution deals with the uncertainty in the repair times. Given the mean repair times for different turbine components we make some assumptions regarding the underlying repair time distribution. We compare the results of a decision support model for the mean times to repair and those repair time distributions. Additionally, distributions with the same mean but different variances are compared under the same conditions. The value of lowering the uncertainty in the repair time is calculated and we find that using distributions significantly decreases the availability, when scheduling maintenance for multiple turbines in a wind park. Having detailed information about the repair time distribution may influence the results of maintenance modeling and might help identify cost factors.

An asymmetrically localized Staufen2-dependent RNA complex regulates maintenance of mammalian neural stem cells.

PubMed

Vessey, John P; Amadei, Gianluca; Burns, Sarah E; Kiebler, Michael A; Kaplan, David R; Miller, Freda D

2012-10-05

The cellular mechanisms that regulate self-renewal versus differentiation of mammalian somatic tissue stem cells are still largely unknown. Here, we asked whether an RNA complex regulates this process in mammalian neural stem cells. We show that the RNA-binding protein Staufen2 (Stau2) is apically localized in radial glial precursors of the embryonic cortex, where it forms a complex with other RNA granule proteins including Pumilio2 (Pum2) and DDX1, and the mRNAs for β-actin and mammalian prospero, prox1. Perturbation of this complex by functional knockdown of Stau2, Pum2, or DDX1 causes premature differentiation of radial glial precursors into neurons and mislocalization and misexpression of prox1 mRNA. Thus, a Stau2- and Pum2-dependent RNA complex directly regulates localization and, potentially, expression of target mRNAs like prox1 in mammalian neural stem cells, and in so doing regulates the balance of stem cell maintenance versus differentiation. Copyright © 2012 Elsevier Inc. All rights reserved.

The structure and organization of lanceolate mechanosensory complexes at mouse hair follicles

PubMed Central

Li, Lishi; Ginty, David D

2014-01-01

In mouse hairy skin, lanceolate complexes associated with three types of hair follicles, guard, awl/auchene and zigzag, serve as mechanosensory end organs. These structures are formed by unique combinations of low-threshold mechanoreceptors (LTMRs), Aβ RA-LTMRs, Aδ-LTMRs, and C-LTMRs, and their associated terminal Schwann cells (TSCs). In this study, we investigated the organization, ultrastructure, and maintenance of longitudinal lanceolate complexes at each hair follicle subtype. We found that TSC processes at hair follicles are tiled and that individual TSCs host axonal endings of more than one LTMR subtype. Electron microscopic analyses revealed unique ultrastructural features of lanceolate complexes that are proposed to underlie mechanotransduction. Moreover, Schwann cell ablation leads to loss of LTMR terminals at hair follicles while, in contrast, TSCs remain associated with hair follicles following skin denervation in adult mice and, remarkably, become re-associated with newly formed axons, indicating a TSC-dependence of lanceolate complex maintenance and regeneration in adults. DOI: http://dx.doi.org/10.7554/eLife.01901.001 PMID:24569481

Structural maintenance of chromosome complexes differentially compact mitotic chromosomes according to genomic context

PubMed Central

Schalbetter, S. A.; Goloborodko, A.; Fudenberg, G.; Belton, J.-M.; Miles, C.; Yu, M.; Dekker, J.; Mirny, L.; Baxter, J.

2017-01-01

Structural Maintenance of Chromosomes (SMC) protein complexes are key determinants of chromosome conformation. Using Hi-C and polymer modeling, we study how cohesin and condensin, two deeply conserved SMC complexes, organize chromosomes in the budding yeast Saccharomyces cerevisiae. The canonical role of cohesin is to co-align sister chromatids whilst condensin generally compacts mitotic chromosomes. We find strikingly different roles for the two complexes in budding yeast mitosis. First, cohesin is responsible for compacting mitotic chromosome arms, independently of sister chromatid cohesion. Polymer simulations demonstrate this role can be fully accounted for through cis-looping of chromatin. Second, condensin is generally dispensable for compaction along chromosome arms. Instead it plays a targeted role compacting the rDNA proximal regions and promoting resolution of peri-centromeric regions. Our results argue that the conserved mechanism of SMC complexes is to form chromatin loops and that distinct SMC-dependent looping activities are selectively deployed to appropriately compact chromosomes. PMID:28825700

Combing Chromosomal DNA Mediated by the SMC Complex: Structure and Mechanisms.

PubMed

Kamada, Katsuhiko; Barillà, Daniela

2018-02-01

Genome maintenance requires various nucleoid-associated factors in prokaryotes. Among them, the SMC (Structural Maintenance of Chromosomes) protein has been thought to play a static role in the organization and segregation of the chromosome during cell division. However, recent studies have shown that the bacterial SMC is required to align left and right arms of the emerging chromosome and that the protein dynamically travels from origin to Ter region. A rod form of the SMC complex mediates DNA bridging and has been recognized as a machinery responsible for DNA loop extrusion, like eukaryotic condensin or cohesin complexes, which act as chromosome organizers. Attention is now turning to how the prototype of the complex is loaded on the entry site and translocated on chromosomal DNA, explaining its overall conformational changes at atomic levels. Here, we review and highlight recent findings concerning the prokaryotic SMC complex and discuss possible mechanisms from the viewpoint of protein architecture. © 2017 The Authors. BioEssays Published by WILEY Periodicals, Inc.

The structure and organization of lanceolate mechanosensory complexes at mouse hair follicles.

PubMed

Li, Lishi; Ginty, David D

2014-02-25

In mouse hairy skin, lanceolate complexes associated with three types of hair follicles, guard, awl/auchene and zigzag, serve as mechanosensory end organs. These structures are formed by unique combinations of low-threshold mechanoreceptors (LTMRs), Aβ RA-LTMRs, Aδ-LTMRs, and C-LTMRs, and their associated terminal Schwann cells (TSCs). In this study, we investigated the organization, ultrastructure, and maintenance of longitudinal lanceolate complexes at each hair follicle subtype. We found that TSC processes at hair follicles are tiled and that individual TSCs host axonal endings of more than one LTMR subtype. Electron microscopic analyses revealed unique ultrastructural features of lanceolate complexes that are proposed to underlie mechanotransduction. Moreover, Schwann cell ablation leads to loss of LTMR terminals at hair follicles while, in contrast, TSCs remain associated with hair follicles following skin denervation in adult mice and, remarkably, become re-associated with newly formed axons, indicating a TSC-dependence of lanceolate complex maintenance and regeneration in adults. DOI: http://dx.doi.org/10.7554/eLife.01901.001.

The Interaction between Checkpoint Kinase 1 (Chk1) and the Minichromosome Maintenance (MCM) Complex Is Required for DNA Damage-induced Chk1 Phosphorylation*

PubMed Central

Han, Xiangzi; Aslanian, Aaron; Fu, Kang; Tsuji, Toshiya; Zhang, Youwei

2014-01-01

Chk1 is an essential mediator of the DNA damage response and cell cycle checkpoint. However, how exactly Chk1 transduces the checkpoint signaling is not fully understood. Here we report the identification of the heterohexamic minichromosome maintenance (MCM) complex that interacts with Chk1 by mass spectrometry. The interaction between Chk1 and the MCM complex was reduced by DNA damage treatment. We show that the MCM complex, at least partially, contributes to the chromatin association of Chk1, allowing for immediate phosphorylation of Chk1 by ataxia telangiectasia mutated and Rad3-related (ATR) in the presence of DNA damage. Further, phosphorylation of Chk1 at ATR sites reduces the interaction between Chk1 and the MCM complex, facilitating chromatin release of phosphorylated Chk1, a critical step in the initiation and amplification of cell cycle checkpoint. Together, these data provide novel insights into the activation of Chk1 in response to DNA damage. PMID:25049228

Psychiatric components of a Health Maintenance Facility (HMF) on Space Station

NASA Technical Reports Server (NTRS)

Santy, Patricia A.

1987-01-01

The operational psychiatric requirements for a comprehensive Health Maintenance Facility (HMF) on a permanently manned Space Station are examined. Consideration is given to the psychological health maintenance program designed for the diagnosis of mental distress in astronauts during flight and for prevention of mental breakdown. The types of mental disorders that can possibly affect the astronauts in flight are discussed, including various organic, psychotic, and affective mental disorders, as well as anxiety, adjustment, and somatoform/dissociative disorders. Special attention is given to therapeutic considerations for psychiatric operations on Space Station, such as restraints, psychopharmacology, psychotherapy, and psychosocial support.

Refurbishment cost study of the thermal protection system of a space shuttle vehicle, phase 2

NASA Technical Reports Server (NTRS)

Haas, D. W.

1972-01-01

The labor costs and techniques associated with the refurbishment and maintenance of representative thermal protection system (TPS) components and their attachment concepts suitable for space shuttle application are defined, characterized, and evaluated from the results of an experimental test program. This program consisted of designing selected TPS concepts, fabricating and assembling test hardware, and performing a time and motion study of specific maintenance functions of the test hardware on a full-scale- mockup. Labor requirements and refurbishment techniques, as they relate to the maintenance functions of inspection, repair, removal, and replacement were identified.

Arabidopsis COG Complex Subunits COG3 and COG8 Modulate Golgi Morphology, Vesicle Trafficking Homeostasis and Are Essential for Pollen Tube Growth

PubMed Central

Li, Yingxin; Li, Pengxiang; Gao, Caiji; Ding, Yu; Lan, Zhiyi; Shi, Zhixuan; Rui, Qingchen; Feng, Yihong; Liu, Yulong; Zhao, Yanxue; Wu, Chengyun; Zhang, Qian; Li, Yan; Jiang, Liwen

2016-01-01

Spatially and temporally regulated membrane trafficking events incorporate membrane and cell wall materials into the pollen tube apex and are believed to underlie the rapid pollen tube growth. In plants, the molecular mechanisms and physiological functions of intra-Golgi transport and Golgi integrity maintenance remain largely unclear. The conserved oligomeric Golgi (COG) complex has been implicated in tethering of retrograde intra-Golgi vesicles in yeast and mammalian cells. Using genetic and cytologic approaches, we demonstrate that T-DNA insertions in Arabidopsis COG complex subunits, COG3 and COG8, cause an absolute, male-specific transmission defect that can be complemented by expression of COG3 and COG8 from the LAT52 pollen promoter, respectively. No obvious abnormalities in the microgametogenesis of the two mutants are observed, but in vitro and in vivo pollen tube growth are defective. COG3 or COG8 proteins fused to green fluorescent protein (GFP) label the Golgi apparatus. In pollen of both mutants, Golgi bodies exhibit altered morphology. Moreover, γ-COP and EMP12 proteins lose their tight association with the Golgi. These defects lead to the incorrect deposition of cell wall components and proteins during pollen tube growth. COG3 and COG8 interact directly with each other, and a structural model of the Arabidopsis COG complex is proposed. We believe that the COG complex helps to modulate Golgi morphology and vesicle trafficking homeostasis during pollen tube tip growth. PMID:27448097

Using Implementation and Dissemination Concepts to Spread 21st-century Well-Child Care at a Health Maintenance Organization

PubMed Central

Beck, Arne; Bergman, David A; Rahm, Alanna K; Dearing, James W; Glasgow, Russell E

2009-01-01

We describe here the use of a conceptual framework for implementing and disseminating in a Health Maintenance Organization an evidence-based model of well-child care (WCC) that includes developmental and preventive services recommended by the American Academy of Pediatrics. Twenty-first Century WCC is a parent-centered, team-based, primary care model that combines online previsit assessments—completed by parents and caregivers regarding clinic-based weight, growth, and development assessments—with vaccinations and anticipatory guidance. Nurses, nurse practitioners, developmental specialists, and pediatricians all play roles in the WCC model. Patient and clinician interaction, health records, and resources are all facilitated through a Web-based diagnostic, management, tracking, and resource information tool. Implementation and dissemination concepts and their attendant practices and tools can reliably be used to augment strategic decisions about how to best disseminate and implement innovations in health care delivery. Unlike innovations that are embedded only in technical systems, validated models of team-based health care have multiple components that must be made compatible with complex sociotechnical systems. Interpersonal communication, work, coordination, and judgment are key processes that affect implementation quality. Implementation can involve tailoring to a particular site and customizing either the model or the organizational context to accommodate it. PMID:20740083

Designing for Change: Interoperability in a scaling and adapting environment

NASA Astrophysics Data System (ADS)

Yarmey, L.

2015-12-01

The Earth Science cyberinfrastructure landscape is constantly changing. Technologies advance and technical implementations are refined or replaced. Data types, volumes, packaging, and use cases evolve. Scientific requirements emerge and mature. Standards shift while systems scale and adapt. In this complex and dynamic environment, interoperability remains a critical component of successful cyberinfrastructure. Through the resource- and priority-driven iterations on systems, interfaces, and content, questions fundamental to stable and useful Earth Science cyberinfrastructure arise. For instance, how are sociotechnical changes planned, tracked, and communicated? How should operational stability balance against 'new and shiny'? How can ongoing maintenance and mitigation of technical debt be managed in an often short-term resource environment? The Arctic Data Explorer is a metadata brokering application developed to enable discovery of international, interdisciplinary Arctic data across distributed repositories. Completely dependent on interoperable third party systems, the Arctic Data Explorer publicly launched in 2013 with an original 3000+ data records from four Arctic repositories. Since then the search has scaled to 25,000+ data records from thirteen repositories at the time of writing. In the final months of original project funding, priorities shift to lean operations with a strategic eye on the future. Here we present lessons learned from four years of Arctic Data Explorer design, development, communication, and maintenance work along with remaining questions and potential directions.

The Deadbeat Paternal Effect of Uncapped Sperm Telomeres on Cell Cycle Progression and Chromosome Behavior in Drosophila melanogaster

PubMed Central

Yamaki, Takuo; Yasuda, Glenn K.; Wakimoto, Barbara T.

2016-01-01

Telomere-capping complexes (TCCs) protect the ends of linear chromosomes from illegitimate repair and end-to-end fusions and are required for genome stability. The identity and assembly of TCC components have been extensively studied, but whether TCCs require active maintenance in nondividing cells remains an open question. Here we show that Drosophila melanogaster requires Deadbeat (Ddbt), a sperm nuclear basic protein (SNBP) that is recruited to the telomere by the TCC and is required for TCC maintenance during genome-wide chromatin remodeling, which transforms spermatids to mature sperm. Ddbt-deficient males produce sperm lacking TCCs. Their offspring delay the initiation of anaphase as early as cycle 1 but progress through the first two cycles. Persistence of uncapped paternal chromosomes induces arrest at or around cycle 3. This early arrest can be rescued by selective elimination of paternal chromosomes and production of gynogenetic haploid or haploid mosaics. Progression past cycle 3 can also occur if embryos have reduced levels of the maternally provided checkpoint kinase Chk2. The findings provide insights into how telomere integrity affects the regulation of the earliest embryonic cell cycles. They also suggest that other SNBPs, including those in humans, may have analogous roles and manifest as paternal effects on embryo quality. PMID:27029731

Modular System to Enable Extravehicular Activity

NASA Technical Reports Server (NTRS)

Sargusingh, Miriam J.

2011-01-01

The ability to perform extravehicular activity (EVA), both human and robotic, has been identified as a key component to space missions to support such operations as assembly and maintenance of space system (e.g. construction and maintenance of the International Space Station), and unscheduled activities to repair an element of the transportation and habitation systems that can only be accessed externally and via unpressurized areas. In order to make human transportation beyond lower earth orbit (BLEO) practical, efficiencies must be incorporated into the integrated transportation systems to reduce system mass and operational complexity. Affordability is also a key aspect to be considered in space system development; this could be achieved through commonality, modularity and component reuse. Another key aspect identified for the EVA system was the ability to produce flight worthy hardware quickly to support early missions and near Earth technology demonstrations. This paper details a conceptual architecture for a modular extravehicular activity system (MEVAS) that would meet these stated needs for EVA capability that is affordable, and that could be produced relatively quickly. Operational concepts were developed to elaborate on the defined needs and define the key capabilities, operational and design constraints, and general timelines. The operational concept lead to a high level design concept for a module that interfaces with various space transportation elements and contains the hardware and systems required to support human and telerobotic EVA; the module would not be self-propelled and would rely on an interfacing element for consumable resources. The conceptual architecture was then compared to EVA Systems used in the Shuttle Orbiter, on the International Space Station to develop high level design concepts that incorporate opportunities for cost savings through hardware reuse, and quick production through the use of existing technologies and hardware designs. An upgrade option was included to make use of the developing suitport technologies.

Forecasting the impact of virtual environment technology on maintenance training

NASA Technical Reports Server (NTRS)

Schlager, Mark S.; Boman, Duane; Piantanida, Tom; Stephenson, Robert

1993-01-01

To assist NASA and the Air Force in determining how and when to invest in virtual environment (VE) technology for maintenance training, we identified possible roles for VE technology in such training, assessed its cost-effectiveness relative to existing technologies, and formulated recommendations for a research agenda that would address instructional and system development issues involved in fielding a VE training system. In the first phase of the study, we surveyed VE developers to forecast capabilities, maturity, and estimated costs for VE component technologies. We then identified maintenance tasks and their training costs through interviews with maintenance technicians, instructors, and training developers. Ten candidate tasks were selected from two classes of maintenance tasks (seven aircraft maintenance and three space maintenance) using five criteria developed to identify types of tasks most likely to benefit from VE training. Three tasks were used as specific cases for cost-benefit analysis. In formulating research recommendations, we considered three aspects of feasibility: technological considerations, cost-effectiveness, and anticipated R&D efforts. In this paper, we describe the major findings in each of these areas and suggest research efforts that we believe will help achieve the goal of a cost-effective VE maintenance training system by the next decade.

Evaluating Virtual Reality and Augmented Reality Training for Industrial Maintenance and Assembly Tasks

ERIC Educational Resources Information Center

Gavish, Nirit; Gutiérrez, Teresa; Webel, Sabine; Rodríguez, Jorge; Peveri, Matteo; Bockholt, Uli; Tecchia, Franco

2015-01-01

The current study evaluated the use of virtual reality (VR) and augmented reality (AR) platforms, developed within the scope of the SKILLS Integrated Project, for industrial maintenance and assembly (IMA) tasks training. VR and AR systems are now widely regarded as promising training platforms for complex and highly demanding IMA tasks. However,…

Experimental and numerical study on the performance of the smooth-land labyrinth seal

NASA Astrophysics Data System (ADS)

Szymanski, A.; Dykas, S.; Wróblewski, W.; Majkut, M.; Strozik, M.

2016-10-01

In turbomachinery the secondary flow system includes flow phenomena occurring outside the main channel, where the gaseous medium performs work on blades. Secondary air distribution constitutes a very complex and closely interrelated system that affects most of the gas turbine components. One of the most important examples of the secondary flow is leakage occurring in seals, e.g. at the rotor and stator tips, on the shaft or on the sides of the blade rim. Owing to its simplicity, low price, easy maintenance and high temperature capability, the labyrinth seal is a prime sealing solution that may be selected from numerous types of sealing structures applied in turbomachinery. For this reason, an experimental study of this particular structure has been carried out. The paper presents leakage performance of the smooth-land labyrinth seal.

Roles of mTOR Signaling in Brain Development.

PubMed

Lee, Da Yong

2015-09-01

mTOR is a serine/threonine kinase composed of multiple protein components. Intracellular signaling of mTOR complexes is involved in many of physiological functions including cell survival, proliferation and differentiation through the regulation of protein synthesis in multiple cell types. During brain development, mTOR-mediated signaling pathway plays a crucial role in the process of neuronal and glial differentiation and the maintenance of the stemness of neural stem cells. The abnormalities in the activity of mTOR and its downstream signaling molecules in neural stem cells result in severe defects of brain developmental processes causing a significant number of brain disorders, such as pediatric brain tumors, autism, seizure, learning disability and mental retardation. Understanding the implication of mTOR activity in neural stem cells would be able to provide an important clue in the development of future brain developmental disorder therapies.

Neoplastic Bone Marrow Niche: Hematopoietic and Mesenchymal Stem Cells

PubMed Central

Saki, Najmaldin; Abroun, Saeid; Farshdousti Hagh, Majid; Asgharei, Farahnaz

2011-01-01

The neoplastic niche comprises complex interactions between multiple cell types and molecules requiring cell-cell signaling as well as local secretion. These niches are important for both the maintenance of cancer stem cells and the induction of neoplastic cells survival and proliferation. Each niche contains a population of tumor stem cells supported by a closely associated vascular bed comprising mesenchyme-derived cells and extracellular matrix. Targeting cancer stem cells and neoplastic niche may provide new therapies to eradicate tumors. Much progress has been very recently made in the understanding of the cellular and molecular interactions in the microenvironment of neoplastic niches. This review article provides an overview of the neoplastic niches in the bone marrow. In addition to highlighting recent advances in the field, we will also discuss components of the niche and their signaling pathways. PMID:23508881

A brain network instantiating approach and avoidance motivation.

PubMed

Spielberg, Jeffrey M; Miller, Gregory A; Warren, Stacie L; Engels, Anna S; Crocker, Laura D; Banich, Marie T; Sutton, Bradley P; Heller, Wendy

2012-09-01

Research indicates that dorsolateral prefrontal cortex (DLPFC) is important for pursuing goals, and areas of DLPFC are differentially involved in approach and avoidance motivation. Given the complexity of the processes involved in goal pursuit, DLPFC is likely part of a network that includes orbitofrontal cortex (OFC), cingulate, amygdala, and basal ganglia. This hypothesis was tested with regard to one component of goal pursuit, the maintenance of goals in the face of distraction. Examination of connectivity with motivation-related areas of DLPFC supported the network hypothesis. Differential patterns of connectivity suggest a distinct role for DLPFC areas, with one involved in selecting approach goals, one in selecting avoidance goals, and one in selecting goal pursuit strategies. Finally, differences in trait motivation moderated connectivity between DLPFC and OFC, suggesting that this connectivity is important for instantiating motivation. Copyright © 2012 Society for Psychophysiological Research.

A Brain Network Instantiating Approach and Avoidance Motivation

PubMed Central

Spielberg, Jeffrey M.; Miller, Gregory A.; Warren, Stacie L.; Engels, Anna S.; Crocker, Laura D.; Banich, Marie T.; Sutton, Bradley P.; Heller, Wendy

2015-01-01

Research indicates that dorsolateral prefrontal cortex (DLPFC) is important for pursuing goals, and areas of DLPFC are differentially involved in approach and avoidance motivation. Given the complexity of the processes involved in goal pursuit, DLPFC is likely part of a network that includes orbitofrontal cortex (OFC), cingulate, amygdala, and basal ganglia. This hypothesis was tested with regard to one component of goal pursuit, the maintenance of goals in the face of distraction. Examination of connectivity with motivation-related areas of DLPFC supported the network hypothesis. Differential patterns of connectivity suggest a distinct role for DLPFC areas, with one involved in selecting approach goals, one in selecting avoidance goals, and one in selecting goal pursuit strategies. Finally, differences in trait motivation moderated connectivity between DLPFC and OFC, suggesting that this connectivity is important for instantiating motivation. PMID:22845892

The design and implementation of the HY-1B Product Archive System

NASA Astrophysics Data System (ADS)

Liu, Shibin; Liu, Wei; Peng, Hailong

2010-11-01

Product Archive System (PAS), as a background system, is the core part of the Product Archive and Distribution System (PADS) which is the center for data management of the Ground Application System of HY-1B satellite hosted by the National Satellite Ocean Application Service of China. PAS integrates a series of updating methods and technologies, such as a suitable data transmittal mode, flexible configuration files and log information in order to make the system with several desirable characteristics, such as ease of maintenance, stability, minimal complexity. This paper describes seven major components of the PAS (Network Communicator module, File Collector module, File Copy module, Task Collector module, Metadata Extractor module, Product data Archive module, Metadata catalogue import module) and some of the unique features of the system, as well as the technical problems encountered and resolved.

The neurobiology of social attachment: A comparative approach to behavioral, neuroanatomical, and neurochemical studies*

PubMed Central

Young, Kimberly A.; Liu, Yan; Wang, Zuoxin

2008-01-01

The formation and maintenance of social bonds in adulthood is an essential component of human health. However studies investigating the underlying neurobiology of such behaviors have been scarce. Microtine rodents offer a unique comparative animal model to explore the neural processes responsible for pair bonding and its associated behaviors. Studies using monogamous prairie voles and other related species have recently offered insight into the neuroanatomical, neurobiological, and neurochemical underpinnings of social attachment. In this review, we will discuss the utility of the microtine rodents in comparative studies by exploring their natural history and social behavior in the laboratory. We will then summarize the data implicating vasopressin, oxytocin, and dopamine in the regulation of pair bonding. Finally, we will discuss the ways in which these neurochemical systems may interact to mediate this complex behavior. PMID:18417423

Secretion and extracellular space travel of Wnt proteins.

PubMed

Gross, Julia Christina; Boutros, Michael

2013-08-01

Wnt signaling pathways control many processes during development, stem cell maintenance and homeostasis, and their aberrant regulation has been linked to diseases in man including diabetes, neurodegeneration and cancer. Wnts are hydrophobic proteins, however, quite paradoxically, they can travel over distances to induce cell-type specific responses. While there has been an initial focus on elucidating the intracellular signaling cascade, discoveries in the past few years have shed light on a highly complex, and regulated secretory process that guides Wnt proteins through the exocytic pathway. Wnt proteins are at least in portion packaged onto extracellular carriers such as exosomes. Similar to dysregulation of components in the Wnt receiving cell, failure to regulate Wnt secretion has been linked to cancer. Here, we review recent discoveries on factors and processes implicated in Wnt secretion. Copyright © 2013 Elsevier Ltd. All rights reserved.

Characterizing and Modeling the Cost of Rework in a Library of Reusable Software Components

NASA Technical Reports Server (NTRS)

Basili, Victor R.; Condon, Steven E.; ElEmam, Khaled; Hendrick, Robert B.; Melo, Walcelio

1997-01-01

In this paper we characterize and model the cost of rework in a Component Factory (CF) organization. A CF is responsible for developing and packaging reusable software components. Data was collected on corrective maintenance activities for the Generalized Support Software reuse asset library located at the Flight Dynamics Division of NASA's GSFC. We then constructed a predictive model of the cost of rework using the C4.5 system for generating a logical classification model. The predictor variables for the model are measures of internal software product attributes. The model demonstrates good prediction accuracy, and can be used by managers to allocate resources for corrective maintenance activities. Furthermore, we used the model to generate proscriptive coding guidelines to improve programming, practices so that the cost of rework can be reduced in the future. The general approach we have used is applicable to other environments.

AUTOMOTIVE DIESEL MAINTENANCE 1. UNIT XXVI, I--CATERPILLAR LUBRICATION SYSTEMS AND COMPONENTS, II--LEARNING ABOUT BRAKES (PART I).

ERIC Educational Resources Information Center

Minnesota State Dept. of Education, St. Paul. Div. of Vocational and Technical Education.

THIS MODULE OF A 30-MODULE COURSE IS DESIGNED TO DEVELOP AN UNDERSTANDING OF THE FUNCTIONS OF DIESEL ENGINE LUBRICATION SYSTEMS AND COMPONENTS AND THE PRINCIPLES OF OPERATION OF BRAKE SYSTEMS USED ON DIESEL POWERED VEHICLES. TOPICS ARE (1) THE NEED FOR OIL, (2) SERVICE CLASSIFICATION OF OILS, (3) CATERPILLAR LUBRICATION SYSTEM COMPONENTS (4)…

A Minimum Delta V Orbit Maintenance Strategy for Low-Altitude Missions Using Burn Parameter Optimization

NASA Technical Reports Server (NTRS)

Brown, Aaron J.

2011-01-01

Orbit maintenance is the series of burns performed during a mission to ensure the orbit satisfies mission constraints. Low-altitude missions often require non-trivial orbit maintenance Delta V due to sizable orbital perturbations and minimum altitude thresholds. A strategy is presented for minimizing this Delta V using impulsive burn parameter optimization. An initial estimate for the burn parameters is generated by considering a feasible solution to the orbit maintenance problem. An low-lunar orbit example demonstrates the Delta V savings from the feasible solution to the optimal solution. The strategy s extensibility to more complex missions is discussed, as well as the limitations of its use.

40 CFR 94.211 - Emission-related maintenance instructions for purchasers.

Code of Federal Regulations, 2010 CFR

2010-07-01

... the Administrator's satisfaction that the engine will function properly only if the component or... section are defined as critical emission-related components. (i) Catalytic convertor. (ii) Electronic... which satisfy one of the conditions defined in paragraphs (j)(2)(i) through (j)(2)(vi) of this section...

77 FR 64442 - Airworthiness Directives; PILATUS AIRCRAFT LTD. Airplanes

Federal Register 2010, 2011, 2012, 2013, 2014

2012-10-22

... Maintenance Manual Temporary Revision No. 04-03, dated October 12, 2012, which transmits Unclassified 12-A/AMP..., dated October 15, 2012, which transmits Unclassified 12-B/AMP-04 Structural and Component Limitations... Revision No. 04-03, dated October 15, 2012, which transmits Unclassified 12-A/AMP-04 Structural, Component...

76 FR 21393 - Agency Information Collection Activities: Proposed Collection; Comment Request

Federal Register 2010, 2011, 2012, 2013, 2014

2011-04-15

... startup cost components or annual operation, maintenance, and purchase of service components. You should describe the methods you use to estimate major cost factors, including system and technology acquisition.... Capital and startup costs include, among other items, computers and software you purchase to prepare for...

76 FR 25367 - Agency Information Collection Activities: Proposed Collection, Comment Request

Federal Register 2010, 2011, 2012, 2013, 2014

2011-05-04

... startup cost components or annual operation, maintenance, and purchase of service components. You should describe the methods you use to estimate major cost factors, including system and technology acquisition.... Capital and startup costs include, among other items, computers and software you purchase to prepare for...

Determining modulus of elasticity of ancient structural timber

Treesearch

Houjiang Zhang; Lei Zhu; Yanliang Sun; Xiping Wang; Haicheng Yan

2011-01-01

During maintenance of ancient timber architectures, it is important to determine mechanical properties of the wood component materials non-destructively and effectively, so that degraded members may be replaced or repaired to avoid structural failure. Experimental materials are four larch (Larix principis-rupprechtii Mayr.) components, which were taken down from the...

Case for Deploying Complex Systems Utilizing Commodity Components

NASA Technical Reports Server (NTRS)

Bryant, Barry S.; Pitts, R. Lee

2003-01-01

When the International Space Station (ISS) finally reached an operational state, many of the Payload Operations and Integration Facility (POIF) hardware components were reaching end of life, COTS product costs were soaring, and the ISS budget was becoming severely constrained. However, most requirement development was complete. In addition, the ISS program is a fully functioning program with at least fifteen years of operational life remaining. Therefore it is critical that any upgrades, refurbishments, or enhancements be accomplished in realtime with minimal disruptions to service. For these and other reasons, it was necessary to ensure the viability of the POIF. Due to the to the breadth of capability of the POIF (a NASA ground station), it is believed that the lessons to be learned by other complex systems are applicable and any solutions garnered by the POIF are applicable to other complex systems as well. With that in mind, a number of new approaches have been investigated to increase the portability of the POIF and reduce the cost of refurbishment, operations, and maintenance. These new approaches were directed at the Total Cost of Ownership (TCO); not only the refurbishment but also current operational difficulties, licensing, and anticipation of the next refurbishment. Our basic premise is that technology had evolved dramatically since the concept of the POIF ground system and we should leverage our experience on this new technological landscape. Fortunately, Moore's law and market forces have changed the landscape considerably. These changes are manifest in five (5) ways that are particularly relevant to POIF: 1. Complex Instruction Set Computing (CISC) processors have advanced to unprecedented levels of compute capacity with a dramatic cost break, 2. Linux has become a major operating system supported by most vendors on a broad range of platforms, 3. Windows(TradeMark) based desktops are pervasive in the office environment, 4. Stable and affordable WindowsTM development environments and tools are available and offer a rich set of capabilities, 5. The WindowsTM 2000 provides a stable client platform, Therefore, five studies were proposed, developed, and are in the current process of deployment which dramatically reduces the cost of operations, maintenance, refurbishment, and deployment of a ground system. Restating and refining the basic premise stated earlier, it is possible to enhance operations through the replacement of hardware and software components with commodity based items wherever applicable. This will dramatically reduce the overall lifecycle cost of the project. The first study leveraged the POIF S secure, three-tier, web architecture to replace the client workstations with lower cost PC platforms. A second study initiated a review of COTS products to examine the level of added value of each product. This study included replacement of some COTS products with custom code, deletions, substitutions, and consolidation of COTS products. Studies three and four reviewed the server architectures of the data distribution systems and Enhanced HOSC System (EHS) command and telemetry system to propose migration to new platforms, both software and hardware. The final study reviewed current IP communication technologies, developed an operational model for flight operations, and demonstrated that voice over IP was practical and could be integrated into operations.

Perioperative and maintenance therapy following first-line therapy as paradigms for drug discovery in urothelial carcinoma

PubMed Central

Hoffman-Censits, Jean; Wong, Yu-Ning

2015-01-01

Perioperative chemotherapy given to increase the chance of cure for localized disease, and maintenance therapy for metastatic disease, represent distinct aspects of the urothelial cancer disease treatment spectrum. The ability to access both pre and post chemotherapy tissue in the neoadjuvant setting provides important opportunities for translational research to test novel therapies and identify predictors of response to therapy. The maintenance setting may be more complex and study design and endpoints need to be determined based on the candidate drugs mechanism of action and toxicity. PMID:25987535

Shame, pride and eating disorders.

PubMed

Goss, Kenneth; Allan, Steven

2009-01-01

This paper explores shame and shame-based responses in eating disorders. Research linking shame with eating disorders and the possible role of shame and pride in the onset and maintenance of eating disorders is reviewed. The experience of shame is likely to be complex, dynamic and variable. However, the key to identifying shame is often via the various coping strategies adopted, which in turn may form part of a maintenance cycle for eating disorder beliefs and behaviours. An outline model of shame and pride cycles in the maintenance of eating disorders is presented with clinical implications.

Intermodal Attention Shifts in Multimodal Working Memory.

PubMed

Katus, Tobias; Grubert, Anna; Eimer, Martin

2017-04-01

Attention maintains task-relevant information in working memory (WM) in an active state. We investigated whether the attention-based maintenance of stimulus representations that were encoded through different modalities is flexibly controlled by top-down mechanisms that depend on behavioral goals. Distinct components of the ERP reflect the maintenance of tactile and visual information in WM. We concurrently measured tactile (tCDA) and visual contralateral delay activity (CDA) to track the attentional activation of tactile and visual information during multimodal WM. Participants simultaneously received tactile and visual sample stimuli on the left and right sides and memorized all stimuli on one task-relevant side. After 500 msec, an auditory retrocue indicated whether the sample set's tactile or visual content had to be compared with a subsequent test stimulus set. tCDA and CDA components that emerged simultaneously during the encoding phase were consistently reduced after retrocues that marked the corresponding (tactile or visual) modality as task-irrelevant. The absolute size of cue-dependent modulations was similar for the tCDA/CDA components and did not depend on the number of tactile/visual stimuli that were initially encoded into WM. Our results suggest that modality-specific maintenance processes in sensory brain regions are flexibly modulated by top-down influences that optimize multimodal WM representations for behavioral goals.

Structural basis for spectrin recognition by ankyrin.

PubMed

Ipsaro, Jonathan J; Mondragón, Alfonso

2010-05-20

Maintenance of membrane integrity and organization in the metazoan cell is accomplished through intracellular tethering of membrane proteins to an extensive, flexible protein network. Spectrin, the principal component of this network, is anchored to membrane proteins through the adaptor protein ankyrin. To elucidate the atomic basis for this interaction, we determined a crystal structure of human betaI-spectrin repeats 13 to 15 in complex with the ZU5-ANK domain of human ankyrin R. The structure reveals the role of repeats 14 to 15 in binding, the electrostatic and hydrophobic contributions along the interface, and the necessity for a particular orientation of the spectrin repeats. Using structural and biochemical data as a guide, we characterized the individual proteins and their interactions by binding and thermal stability analyses. In addition to validating the structural model, these data provide insight into the nature of some mutations associated with cell morphology defects, including those found in human diseases such as hereditary spherocytosis and elliptocytosis. Finally, analysis of the ZU5 domain suggests it is a versatile protein-protein interaction module with distinct interaction surfaces. The structure represents not only the first of a spectrin fragment in complex with its binding partner, but also that of an intermolecular complex involving a ZU5 domain.

Maintenance of tumor initiating cells of defined genetic composition by nucleostemin.

PubMed

Okamoto, Naoko; Yasukawa, Mami; Nguyen, Christine; Kasim, Vivi; Maida, Yoshiko; Possemato, Richard; Shibata, Tatsuhiro; Ligon, Keith L; Fukami, Kiyoko; Hahn, William C; Masutomi, Kenkichi

2011-12-20

Recent work has identified a subset of cells resident in tumors that exhibit properties similar to those found in normal stem cells. Such cells are highly tumorigenic and may be involved in resistance to treatment. However, the genes that regulate the tumor initiating cell (TIC) state are unknown. Here, we show that overexpression of either of the nucleolar GTP-binding proteins nucleostemin (NS) or GNL3L drives the fraction of genetically defined tumor cells that exhibit markers and tumorigenic properties of TICs. Specifically, cells that constitutively express elevated levels of NS or GNL3L exhibit increased TWIST expression, phosphorylation of STAT3, expression of genes that induce pluripotent stem cells, and enhanced radioresistance; in addition, they form tumors even when small numbers of cells are implanted and exhibit an increased propensity to metastasize. GNL3L/NS forms a complex with the telomerase catalytic subunit [human telomerase reverse transcriptase (hTERT)] and the SWItch-Sucrose NonFermentable (SWI-SNF) complex protein brahma-related gene 1 (BRG1), and the expression of each of these components is necessary to facilitate the cancer stem cell state. Together, these observations define a complex composed of TERT, BRG1, and NS/GNL3L that maintains the function of TICs.

Application of reliability-centered maintenance to boiling water reactor emergency core cooling systems fault-tree analysis

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

Choi, Y.A.; Feltus, M.A.

1995-07-01

Reliability-centered maintenance (RCM) methods are applied to boiling water reactor plant-specific emergency core cooling system probabilistic risk assessment (PRA) fault trees. The RCM is a technique that is system function-based, for improving a preventive maintenance (PM) program, which is applied on a component basis. Many PM programs are based on time-directed maintenance tasks, while RCM methods focus on component condition-directed maintenance tasks. Stroke time test data for motor-operated valves (MOVs) are used to address three aspects concerning RCM: (a) to determine if MOV stroke time testing was useful as a condition-directed PM task; (b) to determine and compare the plant-specificmore » MOV failure data from a broad RCM philosophy time period compared with a PM period and, also, compared with generic industry MOV failure data; and (c) to determine the effects and impact of the plant-specific MOV failure data on core damage frequency (CDF) and system unavailabilities for these emergency systems. The MOV stroke time test data from four emergency core cooling systems [i.e., high-pressure coolant injection (HPCI), reactor core isolation cooling (RCIC), low-pressure core spray (LPCS), and residual heat removal/low-pressure coolant injection (RHR/LPCI)] were gathered from Philadelphia Electric Company`s Peach Bottom Atomic Power Station Units 2 and 3 between 1980 and 1992. The analyses showed that MOV stroke time testing was not a predictor for eminent failure and should be considered as a go/no-go test. The failure data from the broad RCM philosophy showed an improvement compared with the PM-period failure rates in the emergency core cooling system MOVs. Also, the plant-specific MOV failure rates for both maintenance philosophies were shown to be lower than the generic industry estimates.« less

Practice makes perfect: self-reported adherence a positive marker of inhaler technique maintenance.

PubMed

Azzi, Elizabeth; Srour, Pamela; Armour, Carol; Rand, Cynthia; Bosnic-Anticevich, Sinthia

2017-04-24

Poor inhaler technique and non-adherence to treatment are major problems in the management of asthma. Patients can be taught how to achieve good inhaler technique, however maintenance remains problematic, with 50% of patients unable to demonstrate correct technique. The aim of this study was to determine the clinical, patient-related and/or device-related factors that predict inhaler technique maintenance. Data from a quality-controlled longitudinal community care dataset was utilized. 238 patients using preventer medications where included. Data consisted of patient demographics, clinical data, medication-related factors and patient-reported outcomes. Mixed effects logistic regression was used to identify predictors of inhaler technique maintenance at 1 month. The variables found to be independently associated with inhaler technique maintenance using logistic regression (Χ 2 (3,n = 238) = 33.24, p < 0.000) were inhaler technique at Visit 1 (OR 7.1), device type (metered dose inhaler and dry powder inhalers) (OR 2.2) and self-reported adherent behavior in the prior 7 days (OR 1.3). This research is the first to unequivocally establish a predictive relationship between inhaler technique maintenance and actual patient adherence, reinforcing the notion that inhaler technique maintenance is more than just a physical skill. Inhaler technique maintenance has an underlying behavioral component, which future studies need to investigate. BEHAVIORAL ELEMENT TO CORRECT LONG-TERM INHALER TECHNIQUES: Patients who consciously make an effort to perfect asthma inhaler technique will maintain their skills long-term. Elizabeth Azzi at the University of Sydney, Australia, and co-workers further add evidence that there is a strong behavioral component to patients retaining correct inhaler technique over time. Poor inhaler technique can limit asthma control, affecting quality of life and increasing the chances of severe exacerbations. Azzi's team followed 238 patients to determine the key predictors of inhaler technique maintenance from factors including age, asthma knowledge and perceived future risks. Correct inhaler technique at initial assessment was the strongest predictor of long-term success, but this was strengthened further when patients reported good adherence to their own medication regimen. This suggests that maintaining correct inhaler technique is more than just a physical skill. Careful guidance towards this 'practice makes perfect' approach may improve patients' long-term technique maintenance.

Asset Management and Facility Equipment Maintenance Nexus: Maintenance Effectiveness

DTIC Science & Technology

2013-09-01

only include the top-level asset, “recreational facility” and its associated buildings, while the asset/component hierarchy of a hydroelectric turbine ...motor windings that can’t be maintained but might indicate a manufacturer defect. What conditions? — If every USACE lock were constructed with a...13-16 99 5. Slip Clutch 5. Sprocket 5. Spur/Pinnion Gear 4. Direct Acting Hydraulic Cylinder 5. Check Valve 5

Expansion of the wilderness values scale with three sub-scales: Personal maintenance, expression and learning, and societal maintenance

Treesearch

Rudy M. Schuster; Ken Cordell; Gary T. Green

2007-01-01

The purpose of this research was to expand the wilderness value scale administered in the 1994 and 2000 versions of the National Survey on Recreation and the Environment using questions included in the 2003 NSRE. A data set of 1,900 cases was randomly split in half. Validity of the additional questions was tested using principal component analysis, a confirmatory...

Ground Vehicle Condition Based Maintenance

DTIC Science & Technology

2010-10-04

Diagnostic Process Map 32 FMEAs Developed : • Diesel Engine • Transmission • Alternators Analysis : • Identify failure modes • Derive design factors and...S&T Initiatives  TARDEC P&D Process Map  Component Testing  ARL CBM Research  AMSAA SDC & Terrain Modeling UNCLASSIFIED 3 CBM+ Overview...UNCLASSIFIED 4 RCM and CBM are core processes for CBM+ System Development • Army Regulation 750-1, 20 Sep 2007, p. 79 - Reliability Centered Maintenance (RCM

Iron-sulfur cluster biogenesis in mammalian cells: new insights into the molecular mechanisms of cluster delivery

PubMed Central

Maio, Nunziata; Rouault, Tracey. A.

2014-01-01

Iron-sulfur (Fe-S) clusters are ancient, ubiquitous cofactors composed of iron and inorganic sulfur. The combination of the chemical reactivity of iron and sulfur, together with many variations of cluster composition, oxidation states and protein environments, enables Fe-S clusters to participate in numerous biological processes. Fe-S clusters are essential to redox catalysis in nitrogen fixation, mitochondrial respiration and photosynthesis, to regulatory sensing in key metabolic pathways (i. e. cellular iron homeostasis and oxidative stress response), and to the replication and maintenance of the nuclear genome. Fe-S cluster biogenesis is a multistep process that involves a complex sequence of catalyzed protein- protein interactions and coupled conformational changes between the components of several dedicated multimeric complexes. Intensive studies of the assembly process have clarified key points in the biogenesis of Fe-S proteins. However several critical questions still remain, such as: what is the role of frataxin? Why do some defects of Fe-S cluster biogenesis cause mitochondrial iron overload? How are specific Fe-S recipient proteins recognized in the process of Fe-S transfer? This review focuses on the basic steps of Fe-S cluster biogenesis, drawing attention to recent advances achieved on the identification of molecular features that guide selection of specific subsets of nascent Fe-S recipients by the cochaperone HSC20. Additionally, it outlines the distinctive phenotypes of human diseases due to mutations in the components of the basic pathway. PMID:25245479

Mutations in the Gene Encoding IFT Dynein Complex Component WDR34 Cause Jeune Asphyxiating Thoracic Dystrophy

PubMed Central

Schmidts, Miriam; Vodopiutz, Julia; Christou-Savina, Sonia; Cortés, Claudio R.; McInerney-Leo, Aideen M.; Emes, Richard D.; Arts, Heleen H.; Tüysüz, Beyhan; D’Silva, Jason; Leo, Paul J.; Giles, Tom C.; Oud, Machteld M.; Harris, Jessica A.; Koopmans, Marije; Marshall, Mhairi; Elçioglu, Nursel; Kuechler, Alma; Bockenhauer, Detlef; Moore, Anthony T.; Wilson, Louise C.; Janecke, Andreas R.; Hurles, Matthew E.; Emmet, Warren; Gardiner, Brooke; Streubel, Berthold; Dopita, Belinda; Zankl, Andreas; Kayserili, Hülya; Scambler, Peter J.; Brown, Matthew A.; Beales, Philip L.; Wicking, Carol; Duncan, Emma L.; Mitchison, Hannah M.

2013-01-01

Bidirectional (anterograde and retrograde) motor-based intraflagellar transport (IFT) governs cargo transport and delivery processes that are essential for primary cilia growth and maintenance and for hedgehog signaling functions. The IFT dynein-2 motor complex that regulates ciliary retrograde protein transport contains a heavy chain dynein ATPase/motor subunit, DYNC2H1, along with other less well functionally defined subunits. Deficiency of IFT proteins, including DYNC2H1, underlies a spectrum of skeletal ciliopathies. Here, by using exome sequencing and a targeted next-generation sequencing panel, we identified a total of 11 mutations in WDR34 in 9 families with the clinical diagnosis of Jeune syndrome (asphyxiating thoracic dystrophy). WDR34 encodes a WD40 repeat-containing protein orthologous to Chlamydomonas FAP133, a dynein intermediate chain associated with the retrograde intraflagellar transport motor. Three-dimensional protein modeling suggests that the identified mutations all affect residues critical for WDR34 protein-protein interactions. We find that WDR34 concentrates around the centrioles and basal bodies in mammalian cells, also showing axonemal staining. WDR34 coimmunoprecipitates with the dynein-1 light chain DYNLL1 in vitro, and mining of proteomics data suggests that WDR34 could represent a previously unrecognized link between the cytoplasmic dynein-1 and IFT dynein-2 motors. Together, these data show that WDR34 is critical for ciliary functions essential to normal development and survival, most probably as a previously unrecognized component of the mammalian dynein-IFT machinery. PMID:24183451

Nutritional treatment in inflammatory bowel disease. An update.

PubMed

Guagnozzi, Danila; González-Castillo, Sonia; Olveira, Antonio; Lucendo, Alfredo J

2012-09-01

enteral (EN) and parenteral (TPN) nutrition exert variable therapeutic effects on the induction and maintenance of remission in inflammatory bowel disease (IBD). This review aims to provide an updated discussion on the complex relationship between diet and IBD. medline, Cochrane and Scopus database searches were conducted. Sources cited in the articles obtained were also searched to identify other potential sources of information. nutritional status is significantly compromised in IBD patients, especially those with Crohn's disease (CD). Apart from restoring malnourishment, dietary components contribute to modulate intestinal immune responses. Nutritional treatment is divided into support therapy and primary therapy to induce and maintain remission through TPN and EN. EN is considered a first-line therapy in children with active CD whereas it is usually used in adult CD patients when corticosteroid therapy is not possible. TPN has limited effects on IBD.En formula composition, in terms of carbohydrates, nitrogen source and bioactive molecules supplementation, differentially influence on IBD treatment outcomes. Other dietary components, such as poorly absorbed short-chain carbohydrate, polyols, and exogenous microparticles, also participate in the etiopathogenesis of IBD. Finally, new approaches to understanding the complex relationship between IBD and diet are provided by nutrigenenomic. further long-term, well-powered studies are required to accurately assess the usefulness of nutrition in treating IBD. In future research, the potential role of nutrient-gene interaction in drug trials and specific dietary formula compositions should be investigated in order to incorporate new knowledge about the etiopathology of IBD into nutritional intervention.

A Dual Role for NOTCH Signaling in Joint Cartilage Maintenance and Osteoarthritis

PubMed Central

Liu, Zhaoyang; Chen, Jianquan; Mirando, Anthony; Wang, Cuicui; Zuscik, Michael J.; O’Keefe, Regis J.; Hilton, Matthew J.

2015-01-01

Loss of NOTCH signaling in postnatal murine joints results in osteoarthritis (OA), indicating a requirement for NOTCH during joint cartilage maintenance. Unexpectedly, NOTCH components are significantly up-regulated in human and murine post-traumatic OA, suggesting either a reparative or pathological role for NOTCH activation in OA. Here we investigated the potential dual role for NOTCH in joint maintenance and OA by generating two mouse models overexpressing the NOTCH1 intracellular domain within postnatal joint cartilage; one with sustained NOTCH activation that likely resembles pathological NOTCH signaling and one with transient NOTCH activation that more closely reflects physiological NOTCH signaling. Sustained NOTCH signaling in joint cartilage leads to an early and progressive OA pathology, while on the contrary, transient NOTCH activation enhances cartilage matrix synthesis and promotes joint maintenance under normal physiological conditions. Using RNA-seq, immunohistochemical, and biochemical approaches we identified several novel targets potentially responsible for NOTCH-mediated cartilage degradation, fibrosis, and OA progression, including components of the IL6/STAT3 and ERK/p38 MAPK pathways; factors that may also contribute to post-traumatic OA development. Collectively, these data demonstrate a dual role for the NOTCH pathway in joint cartilage and identify important downstream NOTCH effectors as potential targets for disease modifying osteoarthritis drugs (DMOADs). PMID:26198357

Software solutions manage the definition, operation, maintenance and configuration control of the National Ignition Facility

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

Dobson, D; Churby, A; Krieger, E

2011-07-25

The National Ignition Facility (NIF) is the world's largest laser composed of millions of individual parts brought together to form one massive assembly. Maintaining control of the physical definition, status and configuration of this structure is a monumental undertaking yet critical to the validity of the shot experiment data and the safe operation of the facility. The NIF business application suite of software provides the means to effectively manage the definition, build, operation, maintenance and configuration control of all components of the National Ignition Facility. State of the art Computer Aided Design software applications are used to generate a virtualmore » model and assemblies. Engineering bills of material are controlled through the Enterprise Configuration Management System. This data structure is passed to the Enterprise Resource Planning system to create a manufacturing bill of material. Specific parts are serialized then tracked along their entire lifecycle providing visibility to the location and status of optical, target and diagnostic components that are key to assessing pre-shot machine readiness. Nearly forty thousand items requiring preventive, reactive and calibration maintenance are tracked through the System Maintenance & Reliability Tracking application to ensure proper operation. Radiological tracking applications ensure proper stewardship of radiological and hazardous materials and help provide a safe working environment for NIF personnel.« less

Unraveling secrets of telomeres: one molecule at a time

PubMed Central

Lin, Jiangguo; Kaur, Parminder; Countryman, Preston; Opresko, Patricia L.; Wang, Hong

2016-01-01

Telomeres play important roles in maintaining the stability of linear chromosomes. Telomere maintenance involves dynamic actions of multiple proteins interacting with long repetitive sequences and complex dynamic DNA structures, such as G-quadruplexes, T-loops and t-circles. Given the heterogeneity and complexity of telomeres, single-molecule approaches are essential to fully understand the structure-function relationships that govern telomere maintenance. In this review, we present a brief overview of the principles of single-molecule imaging and manipulation techniques. We then highlight results obtained from applying these single-molecule techniques for studying structure, dynamics and functions of G-quadruplexes, telomerase, and shelterin proteins. PMID:24569170

Dynamics of Implementation and Maintenance of Organizational Health Interventions.

PubMed

Jalali, Mohammad S; Rahmandad, Hazhir; Bullock, Sally Lawrence; Ammerman, Alice

2017-08-15

In this study, we present case studies to explore the dynamics of implementation and maintenance of health interventions. We analyze how specific interventions are built and eroded, how the building and erosion mechanisms are interconnected, and why we can see significantly different erosion rates across otherwise similar organizations. We use multiple comparative obesity prevention case studies to provide empirical information on the mechanisms of interest, and use qualitative systems modeling to integrate our evolving understanding into an internally consistent and transparent theory of the phenomenon. Our preliminary results identify reinforcing feedback mechanisms, including design of organizational processes, motivation of stakeholders, and communication among stakeholders, which influence implementation and maintenance of intervention components. Over time, these feedback mechanisms may drive a wedge between otherwise similar organizations, leading to distinct configurations of implementation and maintenance processes.

Working memory still needs verbal rehearsal.

PubMed

Lucidi, Annalisa; Langerock, Naomi; Hoareau, Violette; Lemaire, Benoît; Camos, Valérie; Barrouillet, Pierre

2016-02-01

The causal role of verbal rehearsal in working memory has recently been called into question. For example, the SOB-CS (Serial Order in a Box-Complex Span) model assumes that there is no maintenance process for the strengthening of items in working memory, but instead a process of removal of distractors that are involuntarily encoded and create interference with memory items. In the present study, we tested the idea that verbal working memory performance can be accounted for without assuming a causal role of the verbal rehearsal process. We demonstrate in two experiments using a complex span task and a Brown-Peterson paradigm that increasing the number of repetitions of the same distractor (the syllable ba that was read aloud at each of its occurrences on screen) has a detrimental effect on the concurrent maintenance of consonants whereas the maintenance of spatial locations remains unaffected. A detailed analysis of the tasks demonstrates that accounting for this effect within the SOB-CS model requires a series of unwarranted assumptions leading to undesirable further predictions contradicted by available experimental evidence. We argue that the hypothesis of a maintenance mechanism based on verbal rehearsal that is impeded by concurrent articulation still provides the simplest and most compelling account of our results.

Data collection and analysis software development for rotor dynamics testing in spin laboratory

NASA Astrophysics Data System (ADS)

Abdul-Aziz, Ali; Arble, Daniel; Woike, Mark

2017-04-01

Gas turbine engine components undergo high rotational loading another complex environmental conditions. Such operating environment leads these components to experience damages and cracks that can cause catastrophic failure during flights. There are traditional crack detections and health monitoring methodologies currently being used which rely on periodic routine maintenances, nondestructive inspections that often times involve engine and components dis-assemblies. These methods do not also offer adequate information about the faults, especially, if these faults at subsurface or not clearly evident. At NASA Glenn research center, the rotor dynamics laboratory is presently involved in developing newer techniques that are highly dependent on sensor technology to enable health monitoring and prediction of damage and cracks in rotor disks. These approaches are noninvasive and relatively economical. Spin tests are performed using a subscale test article mimicking turbine rotor disk undergoing rotational load. Non-contact instruments such as capacitive and microwave sensors are used to measure the blade tip gap displacement and blade vibrations characteristics in an attempt develop a physics based model to assess/predict the faults in the rotor disk. Data collection is a major component in this experimental-analytical procedure and as a result, an upgrade to an older version of the data acquisition software which is based on LabVIEW program has been implemented to support efficiently running tests and analyze the results. Outcomes obtained from the tests data and related experimental and analytical rotor dynamics modeling including key features of the updated software are presented and discussed.

Changes in mesenteric, renal, and aortic flows with +Gx acceleration

NASA Technical Reports Server (NTRS)

Stone, H. L.; Erickson, H. H.; Sandler, H.

1974-01-01

Previous studies in man and dogs have indicated that the splanchnic bed might contribute to the maintenance of arterial pressure during +Gx acceleration. Eight mongrel dogs were chronically instrumented with Doppler flow probes around the superior mesenteric (SMA) and renal arteries (RA) as well as the terminal aorta (TA). A solid-state pressure transducer was placed in the aorta distal to the flow probe. Using alpha-chloralose anesthesia following a 2-4 week recovery period, the animals were subjected to 120 sec at levels of 5, 10 and 15 +Gx acceleration on a 7.6-m radius centrifuge. The results indicate that both an active component and a mechanical component contribute to the maintenance of arterial pressure during +Gx acceleration.

Complexity and Entropy Analysis of DNMT1 Gene

USDA-ARS?s Scientific Manuscript database

Background: The application of complexity information on DNA sequence and protein in biological processes are well established in this study. Available sequences for DNMT1 gene, which is a maintenance methyltransferase is responsible for copying DNA methylation patterns to the daughter strands durin...

Towards New Multiplatform Hybrid Online Laboratory Models

ERIC Educational Resources Information Center

Rodriguez-Gil, Luis; García-Zubia, Javier; Orduña, Pablo; López-de-Ipiña, Diego

2017-01-01

Online laboratories have traditionally been split between virtual labs, with simulated components; and remote labs, with real components. The former tend to provide less realism but to be easily scalable and less expensive to maintain, while the latter are fully real but tend to require a higher maintenance effort and be more error-prone. This…

Dorsolateral Prefrontal Cortex GABA Concentration in Humans Predicts Working Memory Load Processing Capacity.

PubMed

Yoon, Jong H; Grandelis, Anthony; Maddock, Richard J

2016-11-16

The discovery of neural mechanisms of working memory (WM) would significantly enhance our understanding of complex human behaviors and guide treatment development for WM-related impairments found in neuropsychiatric conditions and aging. Although the dorsolateral prefrontal cortex (DLPFC) has long been considered critical for WM, we still know little about the neural elements and pathways within the DLPFC that support WM in humans. In this study, we tested whether an individual's DLPFC gamma-aminobutryic acid (GABA) content predicts individual differences in WM task performance using a novel behavioral approach. Twenty-three healthy adults completed a task that measured the unique contribution of major WM components (memory load, maintenance, and distraction resistance) to performance. This was done to address the possibility that components have differing GABA dependencies and the failure to parse WM into components would lead to missing true associations with GABA. The subjects then had their DLPFC GABA content measured by single-voxel proton magnetic spectroscopy. We found that individuals with lower DLPFC GABA showed greater performance degradation with higher load, accounting for 31% of variance, p (corrected) = 0.015. This relationship was component, neurochemical, and brain region specific. DLPFC GABA content did not predict performance sensitivity to other components tested; DLPFC glutamate + glutamine and visual cortical GABA content did not predict load sensitivity. These results confirm the involvement of DLPFC GABA in WM load processing in humans and implicate factors controlling DLPFC GABA content in the neural mechanisms of WM and its impairments. This study demonstrated for the first time that the amount of gamma-aminobutryic acid (GABA), the major inhibitory neurotransmitter of the brain, in an individual's prefrontal cortex predicts working memory (WM) task performance. Given that WM is required for many of the most characteristic cognitive and behavioral capabilities in humans, this finding could have a significant impact on our understanding of the neural basis of complex human behavior. Furthermore, this finding suggests that efforts to preserve or increase brain GABA levels could be fruitful in remediating WM-related deficits associated with neuropsychiatric conditions. Copyright © 2016 the authors 0270-6474/16/3611788-07$15.00/0.

Generalized random sign and alert delay models for imperfect maintenance.

PubMed

Dijoux, Yann; Gaudoin, Olivier

2014-04-01

This paper considers the modelling of the process of Corrective and condition-based Preventive Maintenance, for complex repairable systems. In order to take into account the dependency between both types of maintenance and the possibility of imperfect maintenance, Generalized Competing Risks models have been introduced in "Doyen and Gaudoin (J Appl Probab 43:825-839, 2006)". In this paper, we study two classes of these models, the Generalized Random Sign and Generalized Alert Delay models. A Generalized Competing Risks model can be built as a generalization of a particular Usual Competing Risks model, either by using a virtual age framework or not. The models properties are studied and their parameterizations are discussed. Finally, simulation results and an application to real data are presented.

Rotorcraft Diagnostics

NASA Technical Reports Server (NTRS)

Haste, Deepak; Azam, Mohammad; Ghoshal, Sudipto; Monte, James

2012-01-01

Health management (HM) in any engineering systems requires adequate understanding about the system s functioning; a sufficient amount of monitored data; the capability to extract, analyze, and collate information; and the capability to combine understanding and information for HM-related estimation and decision-making. Rotorcraft systems are, in general, highly complex. Obtaining adequate understanding about functioning of such systems is quite difficult, because of the proprietary (restricted access) nature of their designs and dynamic models. Development of an EIM (exact inverse map) solution for rotorcraft requires a process that can overcome the abovementioned difficulties and maximally utilize monitored information for HM facilitation via employing advanced analytic techniques. The goal was to develop a versatile HM solution for rotorcraft for facilitation of the Condition Based Maintenance Plus (CBM+) capabilities. The effort was geared towards developing analytic and reasoning techniques, and proving the ability to embed the required capabilities on a rotorcraft platform, paving the way for implementing the solution on an aircraft-level system for consolidation and reporting. The solution for rotorcraft can he used offboard or embedded directly onto a rotorcraft system. The envisioned solution utilizes available monitored and archived data for real-time fault detection and identification, failure precursor identification, and offline fault detection and diagnostics, health condition forecasting, optimal guided troubleshooting, and maintenance decision support. A variant of the onboard version is a self-contained hardware and software (HW+SW) package that can be embedded on rotorcraft systems. The HM solution comprises components that gather/ingest data and information, perform information/feature extraction, analyze information in conjunction with the dependency/diagnostic model of the target system, facilitate optimal guided troubleshooting, and offer decision support for optimal maintenance.

International Space Station Mechanisms and Maintenance Flight Control Documentation and Training Development

NASA Technical Reports Server (NTRS)

Daugherty, Colin C.

2010-01-01

International Space Station (ISS) crew and flight controller training documentation is used to aid in training operations. The Generic Simulations References SharePoint (Gen Sim) site is a database used as an aid during flight simulations. The Gen Sim site is used to make individual mission segment timelines, data, and flight information easily accessible to instructors. The Waste and Hygiene Compartment (WHC) training schematic includes simple and complex fluid schematics, as well as overall hardware locations. It is used as a teaching aid during WHC lessons for both ISS crew and flight controllers. ISS flight control documentation is used to support all aspects of ISS mission operations. The Quick Look Database and Consolidated Tool Page are imagery-based references used in real-time to help the Operations Support Officer (OSO) find data faster and improve discussions with the Flight Director and Capsule Communicator (CAPCOM). A Quick Look page was created for the Permanent Multipurpose Module (PMM) by locating photos of the module interior, labeling specific hardware, and organizing them in schematic form to match the layout of the PMM interior. A Tool Page was created for the Maintenance Work Area (MWA) by gathering images, detailed drawings, safety information, procedures, certifications, demonstration videos, and general facts of each MWA component and displaying them in an easily accessible and consistent format. Participation in ISS mechanisms and maintenance lessons, mission simulation On-the-Job Training (OJT), and real-time flight OJT was used as an opportunity to train for day-to-day operations as an OSO, as well as learn how to effectively respond to failures and emergencies during mission simulations and real-time flight operations.

Synaptic Regulator α-Synuclein in Dopaminergic Fibers Is Essentially Required for the Maintenance of Subependymal Neural Stem Cells.

PubMed

Perez-Villalba, Ana; Sirerol-Piquer, M Salomé; Belenguer, Germán; Soriano-Cantón, Raúl; Muñoz-Manchado, Ana Belén; Villadiego, Javier; Alarcón-Arís, Diana; Soria, Federico N; Dehay, Benjamin; Bezard, Erwan; Vila, Miquel; Bortolozzi, Analía; Toledo-Aral, Juan José; Pérez-Sánchez, Francisco; Fariñas, Isabel

2018-01-24

Synaptic protein α-synuclein (α-SYN) modulates neurotransmission in a complex and poorly understood manner and aggregates in the cytoplasm of degenerating neurons in Parkinson's disease. Here, we report that α-SYN present in dopaminergic nigral afferents is essential for the normal cycling and maintenance of neural stem cells (NSCs) in the brain subependymal zone of adult male and female mice. We also show that premature senescence of adult NSCs into non-neurogenic astrocytes in mice lacking α-SYN resembles the effects of dopaminergic fiber degeneration resulting from chronic exposure to 1-methyl-4-phenyl-1,2,3,6-tetra-hydropyridine or intranigral inoculation of aggregated toxic α-SYN. Interestingly, NSC loss in α-SYN-deficient mice can be prevented by viral delivery of human α-SYN into their sustantia nigra or by treatment with l-DOPA, suggesting that α-SYN regulates dopamine availability to NSCs. Our data indicate that α-SYN, present in dopaminergic nerve terminals supplying the subependymal zone, acts as a niche component to sustain the neurogenic potential of adult NSCs and identify α-SYN and DA as potential targets to ameliorate neurogenic defects in the aging and diseased brain. SIGNIFICANCE STATEMENT We report an essential role for the protein α-synuclein present in dopaminergic nigral afferents in the regulation of adult neural stem cell maintenance, identifying the first synaptic regulator with an implication in stem cell niche biology. Although the exact role of α-synuclein in neural transmission is not completely clear, our results indicate that it is required for stemness and the preservation of neurogenic potential in concert with dopamine. Copyright © 2018 the authors 0270-6474/18/380815-12$15.00/0.

Limitations of Reliability for Long-Endurance Human Spaceflight

NASA Technical Reports Server (NTRS)

Owens, Andrew C.; de Weck, Olivier L.

2016-01-01

Long-endurance human spaceflight - such as missions to Mars or its moons - will present a never-before-seen maintenance logistics challenge. Crews will be in space for longer and be farther way from Earth than ever before. Resupply and abort options will be heavily constrained, and will have timescales much longer than current and past experience. Spare parts and/or redundant systems will have to be included to reduce risk. However, the high cost of transportation means that this risk reduction must be achieved while also minimizing mass. The concept of increasing system and component reliability is commonly discussed as a means to reduce risk and mass by reducing the probability that components will fail during a mission. While increased reliability can reduce maintenance logistics mass requirements, the rate of mass reduction decreases over time. In addition, reliability growth requires increased test time and cost. This paper assesses trends in test time requirements, cost, and maintenance logistics mass savings as a function of increase in Mean Time Between Failures (MTBF) for some or all of the components in a system. In general, reliability growth results in superlinear growth in test time requirements, exponential growth in cost, and sublinear benefits (in terms of logistics mass saved). These trends indicate that it is unlikely that reliability growth alone will be a cost-effective approach to maintenance logistics mass reduction and risk mitigation for long-endurance missions. This paper discusses these trends as well as other options to reduce logistics mass such as direct reduction of part mass, commonality, or In-Space Manufacturing (ISM). Overall, it is likely that some combination of all available options - including reliability growth - will be required to reduce mass and mitigate risk for future deep space missions.

48 CFR 9.501 - Definition.

Code of Federal Regulations, 2012 CFR

2012-10-01

... consultant when rendering— (1) Services excluded in subpart 37.2; (2) Routine engineering and technical services (such as installation, operation, or maintenance of systems, equipment, software, components, or...

48 CFR 9.501 - Definition.

Code of Federal Regulations, 2014 CFR

2014-10-01

... consultant when rendering— (1) Services excluded in subpart 37.2; (2) Routine engineering and technical services (such as installation, operation, or maintenance of systems, equipment, software, components, or...

48 CFR 9.501 - Definition.

Code of Federal Regulations, 2013 CFR

2013-10-01

... consultant when rendering— (1) Services excluded in subpart 37.2; (2) Routine engineering and technical services (such as installation, operation, or maintenance of systems, equipment, software, components, or...

48 CFR 9.501 - Definition.

Code of Federal Regulations, 2011 CFR

2011-10-01

... consultant when rendering— (1) Services excluded in subpart 37.2; (2) Routine engineering and technical services (such as installation, operation, or maintenance of systems, equipment, software, components, or...

On the preventive management of sediment-related sewer blockages: a combined maintenance and routing optimization approach.

PubMed

Fontecha, John E; Akhavan-Tabatabaei, Raha; Duque, Daniel; Medaglia, Andrés L; Torres, María N; Rodríguez, Juan Pablo

In this work we tackle the problem of planning and scheduling preventive maintenance (PM) of sediment-related sewer blockages in a set of geographically distributed sites that are subject to non-deterministic failures. To solve the problem, we extend a combined maintenance and routing (CMR) optimization approach which is a procedure based on two components: (a) first a maintenance model is used to determine the optimal time to perform PM operations for each site and second (b) a mixed integer program-based split procedure is proposed to route a set of crews (e.g., sewer cleaners, vehicles equipped with winches or rods and dump trucks) in order to perform PM operations at a near-optimal minimum expected cost. We applied the proposed CMR optimization approach to two (out of five) operative zones in the city of Bogotá (Colombia), where more than 100 maintenance operations per zone must be scheduled on a weekly basis. Comparing the CMR against the current maintenance plan, we obtained more than 50% of cost savings in 90% of the sites.

Implementing a Daily Maintenance Care Bundle to Prevent Central Line-Associated Bloodstream Infections in Pediatric Oncology Patients.

PubMed

Duffy, Elizabeth A; Rodgers, Cheryl C; Shever, Leah L; Hockenberry, Marilyn J

2015-01-01

Eliminating central line-associated bloodstream infection (CLABSI) is a national priority. Central venous catheter (CVC) care bundles are composed of a series of interventions that, when used together, are effective in preventing CLABSI. A CVC daily maintenance care bundle includes procedural guidelines for hygiene, dressing changes, and access as well as specific timeframes. Failure to complete one of the components of the care bundle predisposes the patient to a bloodstream infection. A nurse-led multidisciplinary team implemented and, for six months, sustained a daily maintenance care bundle for pediatric oncology patients. This quality improvement project focused on nursing staffs' implementation of the daily maintenance care bundle and the sustainment of the intervention. The project used a pre-post program design to evaluate outcomes of CVC daily maintenance care bundle compliancy and CLABSI. A statistically significant increase between the pre- and post-assessments of the compliance was noted with the CVC daily maintenance care bundle. CLABSI infection rates decreased during the intervention. Strategies to implement practice change and promote sustainability are discussed. © 2015 by Association of Pediatric Hematology/Oncology Nurses.

Integrated Blade Inspection System (IBIS) Upgrade Study

DTIC Science & Technology

1992-12-01

the maintenance contract for the IBIS is equally divided among its 4-1 three major components, then the FPIM’s maintenance costs account for 33% of...network to the blade inspection problem, the output of the network must be interpreted in a slightly different manner to account for the cost of the...missed detections, respectively. The costs associated with the two types of error are drastically different and should be accounted for in the

Resolving complex chromosome structures during meiosis: versatile deployment of Smc5/6.

PubMed

Verver, Dideke E; Hwang, Grace H; Jordan, Philip W; Hamer, Geert

2016-03-01

The Smc5/6 complex, along with cohesin and condensin, is a member of the structural maintenance of chromosome (SMC) family, large ring-like protein complexes that are essential for chromatin structure and function. Thanks to numerous studies of the mitotic cell cycle, Smc5/6 has been implicated to have roles in homologous recombination, restart of stalled replication forks, maintenance of ribosomal DNA (rDNA) and heterochromatin, telomerase-independent telomere elongation, and regulation of chromosome topology. The nature of these functions implies that the Smc5/6 complex also contributes to the profound chromatin changes, including meiotic recombination, that characterize meiosis. Only recently, studies in diverse model organisms have focused on the potential meiotic roles of the Smc5/6 complex. Indeed, Smc5/6 appears to be essential for meiotic recombination. However, due to both the complexity of the process of meiosis and the versatility of the Smc5/6 complex, many additional meiotic functions have been described. In this review, we provide a clear overview of the multiple functions found so far for the Smc5/6 complex in meiosis. Additionally, we compare these meiotic functions with the known mitotic functions in an attempt to find a common denominator and thereby create clarity in the field of Smc5/6 research.

Hollow shaft integrated health monitoring system for railroad wheels

NASA Astrophysics Data System (ADS)

Frankenstein, B.; Hentschel, D.; Pridoehl, E.; Schubert, F.

2005-05-01

The economic efficiency and competitiveness of environment-friendly rail transportation depends on safety, availability and maintenance of single highly loaded structure components. Until now these components have been changed in fixed maintenance intervals irrespective of any usage related conditions. With the knowledge and evaluation of the component conditions, life cycle costs can be reduced by means of optimized maintenance and/or "fit for purpose" design. For example, rail-bound vehicle wheel sets are among the most highly stressed travelling gear components of the bogie. if such a component fails, a serious accident may occur. For this reason, a health monitoring system based on the interpretation of ultrasonic sound signatures has been developed. First, the ultrasonic waves generated by an artificial defect on the outer wheel tread of a railroad wheel towards an acoustic sensor, placed inside the hollow shaft of the railroad axis were simulated with a EFIT (Elastodynamic Finite Integration Technique). The results achieved proved that relevant signals can be found in a frequency range up to 300 kHz. Based on this a diagnostic unit was designed and built for application under rotation conditions, which consists of a piezo-electric sensor, primary electronics, an analog-to-digital converter, a digital signal processor, a trigger unit, and a telemetric transmitter. This diagnostic unit was integrated in the hollow shaft of a railroad wheel axis, a component of a special laboratory test rig. Algorithms which allow for the rotation-synchronized processing of acoustic signals were implemented into the rotating diagnostic unit. After successfully completing a campaign for this test rig, a second test was performed inside the wheel/railroad simulation test rig of the Deutsche Bahn AG under railroad-like conditions. The data generated inside the hollow shaft of the railroad wheel axis by the diagnostic unit were telemetrically transmitted to an industrial computer. The detection of artificial defects of different sizes is shown in correlation with theoretical assumptions.

Analysis of Maintenance Service Contracts for Dump Trucks Used in Mining Industry with Simulation Approach

NASA Astrophysics Data System (ADS)

Dymasius, A.; Wangsaputra, R.; Iskandar, B. P.

2016-02-01

A mining company needs high availability of dump trucks used to haul mining materials. As a result, an effective maintenance action is required to keep the dump trucks in a good condition and hence reducing failure and downtime of the dump trucks. To carry out maintenance in-house requires a high intensive maintenance facility and high skilled maintenance specialists. Often, outsourcing maintenance is an economic option for the company. An external agent takes a proactive action with offering some maintenance contract options to the owner. The decision problem for the owner is to decide the best option and for the agent is to determine the optimal price for each option offered. A non-cooperative game-theory is used to formulate the decision problems for the owner and the agent. We consider that failure pattern of each truck follows a non-homogeneous Poisson process (NHPP) and a queueing theory with multiple servers is used to estimate the downtime. As it involves high complexity to model downtime using a queueing theory, then in this paper we use a simulation method. Furthermore, we conduct experiment to seek for the best number of maintenance facilities (servers) which minimises maintenance and penalty costs incurred to the agent.

KSC-2011-1395

NASA Image and Video Library

2011-02-08

CAPE CANAVERAL, Fla. -- NASA's Kennedy Space Center in Florida hosts a ribbon-cutting ceremony at a new 18,500-square-foot Electrical Maintenance Facility (EMF) officially opening for business. Addressing the attendees is NASA Construction of Facility Project Manager Nick Rivieccio. Located in Kennedy's Launch Complex 39 area, the EMF will provide new and renovated space for maintenance shops, offices, and equipment and material storage in support of the electrical maintenance functions for the center. The facility is projected to receive Gold certification under the U.S. Green Building Council’s Leadership in Energy and Environmental Design (LEED) rating system. Photo credit: NASA/ Troy Cryder

KSC-2011-1397

NASA Image and Video Library

2011-02-08

CAPE CANAVERAL, Fla. -- NASA's Kennedy Space Center in Florida hosts a ribbon-cutting ceremony at a new 18,500-square-foot Electrical Maintenance Facility (EMF) officially opening for business. Addressing the attendees is Kennedy Director of Operations Mike Benik. Located in Kennedy's Launch Complex 39 area, the EMF will provide new and renovated space for maintenance shops, offices, and equipment and material storage in support of the electrical maintenance functions for the center. The facility is projected to receive Gold certification under the U.S. Green Building Council’s Leadership in Energy and Environmental Design (LEED) rating system. Photo credit: NASA/ Troy Cryder

KSC-2011-1396

NASA Image and Video Library

2011-02-08

CAPE CANAVERAL, Fla. -- NASA's Kennedy Space Center in Florida hosts a ribbon-cutting ceremony at a new 18,500-square-foot Electrical Maintenance Facility (EMF) officially opening for business. Addressing the attendees is Kennedy Center Director Bob Cabana. Located in Kennedy's Launch Complex 39 area, the EMF will provide new and renovated space for maintenance shops, offices, and equipment and material storage in support of the electrical maintenance functions for the center. The facility is projected to receive Gold certification under the U.S. Green Building Council’s Leadership in Energy and Environmental Design (LEED) rating system. Photo credit: NASA/ Troy Cryder

Cost Effectiveness of Two versus Three Levels of Maintenance for Turbine Engines in the Air Force Inventory

DTIC Science & Technology

1990-09-01

increasing 2 complexity of Air Force weapon systems makes the estimation of LCC an extremely difficult task. To accomplish this, mathematical models are...maintenance is nearly horizontal. A reduction in this rate from 2.8 to 2.6 (approx. 7%j resulted in cost savings of around 0.1% for the three lvel concept. The

Optimal Preventive Maintenance Schedule based on Lifecycle Cost and Time-Dependent Reliability

DTIC Science & Technology

2011-11-10

Page 1 of 16 UNCLASSIFIED: Distribution Statement A. Approved for public release. 12IDM-0064 Optimal Preventive Maintenance Schedule based... 1 . INTRODUCTION Customers and product manufacturers demand continued functionality of complex equipment and processes. Degradation of material...Documentation Page Form ApprovedOMB No. 0704-0188 Public reporting burden for the collection of information is estimated to average 1 hour per response

Cost analysis of equipment failure of a radiology department and possible choices about maintenance.

PubMed

Grisi, Guido; Dalla Palma, Ludovico; Rimondini, Allesandra; Palmolungo, Chiara; Cuttin Zernich, Roberto; Pozzi Mucelli, Roberto

2002-01-01

Our aim was to evaluate the economic impact of equipment failures in a radiology department with a view to guiding maintenance policy decisions. We assessed the negative economic impact caused by the interruption of activity of a radiodiagnostics section due to equipment failure, taking into account: the effects occurring during the first day of equipment down-time (assuming that the equipment failure occurs in the middle of the shift) and the effects during the following days until the repair of the failure; the effects occurring in the short- and long-term. To exemplify the negative impact of inactivity due to equipment failure, we chose three radiology sections with different levels of technological and operational complexity (chest radiology, gastrointestinal radiology and remote-controlled diagnostics). For each, we evaluated the loss of contribution margin and the idle capacity costs (short- and long-term impact). The negative economic effects were: for thoracic radiology, 496,77 Euro in the first day, and 30,99 Euro from the second day onwards; for gastrointestinal radiology, 526,40 Euro for the first day, and 730,39 Euro from the second day onwards; for remote-controlled diagnostics, 786,25 Euro for the first day, and 927,67 Euro from the second days onwards. Our results indicate that the level of idle capacity costs (mainly equipment and staff) increases with the complexity of the equipment, whereas the contribution margin appears to fluctuate, because the charges are state-imposed and do not vary with the complexity of equipment. Moreover, our analysis shows that if the workload of a broken machine can easily be assigned to an additional shift using another machine, losses are considerably reduced from the second day onwards. Once the negative economic impact of equipment failures has been evaluated, the second step is to choose the best kind of maintenance. A sound calculation of the economic impact of equipment failures is very useful for guiding the head of department and the hospital manager in deciding whether to purchase maintenance services (or a long-term guarantee) from the equipment manufacturer, to set up an auxiliary centre for maintenance and repair, or to purchase a third-party maintenance contract.

A Genuine TEAM Player

NASA Technical Reports Server (NTRS)

2001-01-01

Qualtech Systems, Inc. developed a complete software system with capabilities of multisignal modeling, diagnostic analysis, run-time diagnostic operations, and intelligent interactive reasoners. Commercially available as the TEAMS (Testability Engineering and Maintenance System) tool set, the software can be used to reveal unanticipated system failures. The TEAMS software package is broken down into four companion tools: TEAMS-RT, TEAMATE, TEAMS-KB, and TEAMS-RDS. TEAMS-RT identifies good, bad, and suspect components in the system in real-time. It reports system health results from onboard tests, and detects and isolates failures within the system, allowing for rapid fault isolation. TEAMATE takes over from where TEAMS-RT left off by intelligently guiding the maintenance technician through the troubleshooting procedure, repair actions, and operational checkout. TEAMS-KB serves as a model management and collection tool. TEAMS-RDS (TEAMS-Remote Diagnostic Server) has the ability to continuously assess a system and isolate any failure in that system or its components, in real time. RDS incorporates TEAMS-RT, TEAMATE, and TEAMS-KB in a large-scale server architecture capable of providing advanced diagnostic and maintenance functions over a network, such as the Internet, with a web browser user interface.

Maintenance of item and order information in verbal working memory.

PubMed

Camos, Valérie; Lagner, Prune; Loaiza, Vanessa M

2017-09-01

Although verbal recall of item and order information is well-researched in short-term memory paradigms, there is relatively little research concerning item and order recall from working memory. The following study examined whether manipulating the opportunity for attentional refreshing and articulatory rehearsal in a complex span task differently affected the recall of item- and order-specific information of the memoranda. Five experiments varied the opportunity for articulatory rehearsal and attentional refreshing in a complex span task, but the type of recall was manipulated between experiments (item and order, order only, and item only recall). The results showed that impairing attentional refreshing and articulatory rehearsal similarly affected recall regardless of whether the scoring procedure (Experiments 1 and 4) or recall requirements (Experiments 2, 3, and 5) reflected item- or order-specific recall. This implies that both mechanisms sustain the maintenance of item and order information, and suggests that the common cumulative functioning of these two mechanisms to maintain items could be at the root of order maintenance.

Mgm101p Is a Novel Component of the Mitochondrial Nucleoid That Binds DNA and Is Required for the Repair of Oxidatively Damaged Mitochondrial DNA

PubMed Central

Meeusen, Shelly; Tieu, Quinton; Wong, Edith; Weiss, Eric; Schieltz, David; Yates, John R.; Nunnari, Jodi

1999-01-01

Maintenance of mitochondrial DNA (mtDNA) during cell division is required for progeny to be respiratory competent. Maintenance involves the replication, repair, assembly, segregation, and partitioning of the mitochondrial nucleoid. MGM101 has been identified as a gene essential for mtDNA maintenance in S. cerevisiae, but its role is unknown. Using liquid chromatography coupled with tandem mass spectrometry, we identified Mgm101p as a component of highly enriched nucleoids, suggesting that it plays a nucleoid-specific role in maintenance. Subcellular fractionation, indirect immunofluorescence and GFP tagging show that Mgm101p is exclusively associated with the mitochondrial nucleoid structure in cells. Furthermore, DNA affinity chromatography of nucleoid extracts indicates that Mgm101p binds to DNA, suggesting that its nucleoid localization is in part due to this activity. Phenotypic analysis of cells containing a temperature sensitive mgm101 allele suggests that Mgm101p is not involved in mtDNA packaging, segregation, partitioning or required for ongoing mtDNA replication. We examined Mgm101p's role in mtDNA repair. As compared with wild-type cells, mgm101 cells were more sensitive to mtDNA damage induced by UV irradiation and were hypersensitive to mtDNA damage induced by gamma rays and H2O2 treatment. Thus, we propose that Mgm101p performs an essential function in the repair of oxidatively damaged mtDNA that is required for the maintenance of the mitochondrial genome. PMID:10209025

PDF cells are a GABA-responsive wake-promoting component of the Drosophila sleep circuit.

PubMed

Parisky, Katherine M; Agosto, Jose; Pulver, Stefan R; Shang, Yuhua; Kuklin, Elena; Hodge, James J L; Kang, Kyeongjin; Kang, Keongjin; Liu, Xu; Garrity, Paul A; Rosbash, Michael; Griffith, Leslie C

2008-11-26

Daily sleep cycles in humans are driven by a complex circuit within which GABAergic sleep-promoting neurons oppose arousal. Drosophila sleep has recently been shown to be controlled by GABA, which acts on unknown cells expressing the Rdl GABAA receptor. We identify here the relevant Rdl-containing cells as PDF-expressing small and large ventral lateral neurons (LNvs) of the circadian clock. LNv activity regulates total sleep as well as the rate of sleep onset; both large and small LNvs are part of the sleep circuit. Flies mutant for pdf or its receptor are hypersomnolent, and PDF acts on the LNvs themselves to control sleep. These features of the Drosophila sleep circuit, GABAergic control of onset and maintenance as well as peptidergic control of arousal, support the idea that features of sleep-circuit architecture as well as the mechanisms governing the behavioral transitions between sleep and wake are conserved between mammals and insects.

A network property necessary for concentration robustness

NASA Astrophysics Data System (ADS)

Eloundou-Mbebi, Jeanne M. O.; Küken, Anika; Omranian, Nooshin; Kleessen, Sabrina; Neigenfind, Jost; Basler, Georg; Nikoloski, Zoran

2016-10-01

Maintenance of functionality of complex cellular networks and entire organisms exposed to environmental perturbations often depends on concentration robustness of the underlying components. Yet, the reasons and consequences of concentration robustness in large-scale cellular networks remain largely unknown. Here, we derive a necessary condition for concentration robustness based only on the structure of networks endowed with mass action kinetics. The structural condition can be used to design targeted experiments to study concentration robustness. We show that metabolites satisfying the necessary condition are present in metabolic networks from diverse species, suggesting prevalence of this property across kingdoms of life. We also demonstrate that our predictions about concentration robustness of energy-related metabolites are in line with experimental evidence from Escherichia coli. The necessary condition is applicable to mass action biological systems of arbitrary size, and will enable understanding the implications of concentration robustness in genetic engineering strategies and medical applications.

Distributed computing for macromolecular crystallography

PubMed Central

Krissinel, Evgeny; Uski, Ville; Lebedev, Andrey; Ballard, Charles

2018-01-01

Modern crystallographic computing is characterized by the growing role of automated structure-solution pipelines, which represent complex expert systems utilizing a number of program components, decision makers and databases. They also require considerable computational resources and regular database maintenance, which is increasingly more difficult to provide at the level of individual desktop-based CCP4 setups. On the other hand, there is a significant growth in data processed in the field, which brings up the issue of centralized facilities for keeping both the data collected and structure-solution projects. The paradigm of distributed computing and data management offers a convenient approach to tackling these problems, which has become more attractive in recent years owing to the popularity of mobile devices such as tablets and ultra-portable laptops. In this article, an overview is given of developments by CCP4 aimed at bringing distributed crystallographic computations to a wide crystallographic community. PMID:29533240

Distributed computing for macromolecular crystallography.

PubMed

Krissinel, Evgeny; Uski, Ville; Lebedev, Andrey; Winn, Martyn; Ballard, Charles

2018-02-01

Modern crystallographic computing is characterized by the growing role of automated structure-solution pipelines, which represent complex expert systems utilizing a number of program components, decision makers and databases. They also require considerable computational resources and regular database maintenance, which is increasingly more difficult to provide at the level of individual desktop-based CCP4 setups. On the other hand, there is a significant growth in data processed in the field, which brings up the issue of centralized facilities for keeping both the data collected and structure-solution projects. The paradigm of distributed computing and data management offers a convenient approach to tackling these problems, which has become more attractive in recent years owing to the popularity of mobile devices such as tablets and ultra-portable laptops. In this article, an overview is given of developments by CCP4 aimed at bringing distributed crystallographic computations to a wide crystallographic community.

Skeletal Effects of Growth Hormone and Insulin-like Growth Factor-I Therapy

PubMed Central

Lindsey, Richard C.; Mohan, Subburaman

2015-01-01

The growth hormone/insulin-like growth factor (GH/IGF) axis is critically important for the regulation of bone formation, and deficiencies in this system have been shown to contribute to the development of osteoporosis and other diseases of low bone mass. The GH/IGF axis is regulated by a complex set of hormonal and local factors which can act to regulate this system at the level of the ligands, receptors, IGF binding proteins (IGFBPs), or IGFBP proteases. A combination of in vitro studies, transgenic animal models, and clinical human investigations has provided ample evidence of the importance of the endocrine and local actions of both GH and IGF-I, the two major components of the GH/IGF axis, in skeletal growth and maintenance. GH- and IGF-based therapies provide a useful avenue of approach for the prevention and treatment of diseases such as osteoporosis. PMID:26408965

Openings in the wall: transnational migrants, labor unions, and U.S. immigration policy.

PubMed

Haus, L A

1995-01-01

"This article seeks to enhance our understanding of why the United States resisted restrictionist [immigration] legislation in the late twentieth century during times when one may have expected a movement toward closure, as occurred in the 1920s.... The article will supplement a state-centric approach with insights from the perspective of complex interdependence--the significance of transnational relations and the blurring of foreign and domestic politics. I will argue that the societal groups that influence the formation of U.S. immigration policy contain a transnational component, which contributes to the maintenance of relatively open legislation.... More specifically, I will argue that the transnationalization of the labor market...blurs the boundaries between foreign and domestic constituents for unions, causing unions to resist those restrictionist immigration measures that impede organization of foreign-born workers. Hence, the pressures for restrictionism are weaker than anticipated by the conventional wisdom that expects labor to lobby for closure." excerpt

A network property necessary for concentration robustness.

PubMed

Eloundou-Mbebi, Jeanne M O; Küken, Anika; Omranian, Nooshin; Kleessen, Sabrina; Neigenfind, Jost; Basler, Georg; Nikoloski, Zoran

2016-10-19

Maintenance of functionality of complex cellular networks and entire organisms exposed to environmental perturbations often depends on concentration robustness of the underlying components. Yet, the reasons and consequences of concentration robustness in large-scale cellular networks remain largely unknown. Here, we derive a necessary condition for concentration robustness based only on the structure of networks endowed with mass action kinetics. The structural condition can be used to design targeted experiments to study concentration robustness. We show that metabolites satisfying the necessary condition are present in metabolic networks from diverse species, suggesting prevalence of this property across kingdoms of life. We also demonstrate that our predictions about concentration robustness of energy-related metabolites are in line with experimental evidence from Escherichia coli. The necessary condition is applicable to mass action biological systems of arbitrary size, and will enable understanding the implications of concentration robustness in genetic engineering strategies and medical applications.

A network property necessary for concentration robustness

PubMed Central

Eloundou-Mbebi, Jeanne M. O.; Küken, Anika; Omranian, Nooshin; Kleessen, Sabrina; Neigenfind, Jost; Basler, Georg; Nikoloski, Zoran

2016-01-01

Maintenance of functionality of complex cellular networks and entire organisms exposed to environmental perturbations often depends on concentration robustness of the underlying components. Yet, the reasons and consequences of concentration robustness in large-scale cellular networks remain largely unknown. Here, we derive a necessary condition for concentration robustness based only on the structure of networks endowed with mass action kinetics. The structural condition can be used to design targeted experiments to study concentration robustness. We show that metabolites satisfying the necessary condition are present in metabolic networks from diverse species, suggesting prevalence of this property across kingdoms of life. We also demonstrate that our predictions about concentration robustness of energy-related metabolites are in line with experimental evidence from Escherichia coli. The necessary condition is applicable to mass action biological systems of arbitrary size, and will enable understanding the implications of concentration robustness in genetic engineering strategies and medical applications. PMID:27759015

Dormant origins as a built-in safeguard in eukaryotic DNA replication against genome instability and disease development.

PubMed

Shima, Naoko; Pederson, Kayla D

2017-08-01

DNA replication is a prerequisite for cell proliferation, yet it can be increasingly challenging for a eukaryotic cell to faithfully duplicate its genome as its size and complexity expands. Dormant origins now emerge as a key component for cells to successfully accomplish such a demanding but essential task. In this perspective, we will first provide an overview of the fundamental processes eukaryotic cells have developed to regulate origin licensing and firing. With a special focus on mammalian systems, we will then highlight the role of dormant origins in preventing replication-associated genome instability and their functional interplay with proteins involved in the DNA damage repair response for tumor suppression. Lastly, deficiencies in the origin licensing machinery will be discussed in relation to their influence on stem cell maintenance and human diseases. Copyright © 2017 Elsevier B.V. All rights reserved.

Repair of DNA Damage Induced by the Cytidine Analog Zebularine Requires ATR and ATM in Arabidopsis[OPEN

PubMed Central

Liu, Chun-Hsin; Finke, Andreas; Díaz, Mariana; Rozhon, Wilfried; Poppenberger, Brigitte; Baubec, Tuncay; Pecinka, Ales

2015-01-01

DNA damage repair is an essential cellular mechanism that maintains genome stability. Here, we show that the nonmethylable cytidine analog zebularine induces a DNA damage response in Arabidopsis thaliana, independent of changes in DNA methylation. In contrast to genotoxic agents that induce damage in a cell cycle stage-independent manner, zebularine induces damage specifically during strand synthesis in DNA replication. The signaling of this damage is mediated by additive activity of ATAXIA TELANGIECTASIA MUTATED AND RAD3-RELATED and ATAXIA TELANGIECTASIA MUTATED kinases, which cause postreplicative cell cycle arrest and increased endoreplication. The repair requires a functional STRUCTURAL MAINTENANCE OF CHROMOSOMES5 (SMC5)-SMC6 complex and is accomplished predominantly by synthesis-dependent strand-annealing homologous recombination. Here, we provide insight into the response mechanism for coping with the genotoxic effects of zebularine and identify several components of the zebularine-induced DNA damage repair pathway. PMID:26023162

Dynamics of Implementation and Maintenance of Organizational Health Interventions

PubMed Central

Rahmandad, Hazhir; Bullock, Sally Lawrence; Ammerman, Alice

2017-01-01

In this study, we present case studies to explore the dynamics of implementation and maintenance of health interventions. We analyze how specific interventions are built and eroded, how the building and erosion mechanisms are interconnected, and why we can see significantly different erosion rates across otherwise similar organizations. We use multiple comparative obesity prevention case studies to provide empirical information on the mechanisms of interest, and use qualitative systems modeling to integrate our evolving understanding into an internally consistent and transparent theory of the phenomenon. Our preliminary results identify reinforcing feedback mechanisms, including design of organizational processes, motivation of stakeholders, and communication among stakeholders, which influence implementation and maintenance of intervention components. Over time, these feedback mechanisms may drive a wedge between otherwise similar organizations, leading to distinct configurations of implementation and maintenance processes. PMID:28809807

Predicting Protein Relationships to Human Pathways through a Relational Learning Approach Based on Simple Sequence Features.

PubMed

García-Jiménez, Beatriz; Pons, Tirso; Sanchis, Araceli; Valencia, Alfonso

2014-01-01

Biological pathways are important elements of systems biology and in the past decade, an increasing number of pathway databases have been set up to document the growing understanding of complex cellular processes. Although more genome-sequence data are becoming available, a large fraction of it remains functionally uncharacterized. Thus, it is important to be able to predict the mapping of poorly annotated proteins to original pathway models. We have developed a Relational Learning-based Extension (RLE) system to investigate pathway membership through a function prediction approach that mainly relies on combinations of simple properties attributed to each protein. RLE searches for proteins with molecular similarities to specific pathway components. Using RLE, we associated 383 uncharacterized proteins to 28 pre-defined human Reactome pathways, demonstrating relative confidence after proper evaluation. Indeed, in specific cases manual inspection of the database annotations and the related literature supported the proposed classifications. Examples of possible additional components of the Electron transport system, Telomere maintenance and Integrin cell surface interactions pathways are discussed in detail. All the human predicted proteins in the 2009 and 2012 releases 30 and 40 of Reactome are available at http://rle.bioinfo.cnio.es.

Protein myozap--a late addition to the molecular ensembles of various kinds of adherens junctions.

PubMed

Rickelt, Steffen; Kuhn, Caecilia; Winter-Simanowski, Stefanie; Zimbelmann, Ralf; Frey, Norbert; Franke, Werner Wilhelm

2011-12-01

The protein myozap, a polypeptide of 54 kDa, has recently been identified as a component of the cytoplasmic plaques of the composite junctions (areae compositae) in the myocardiac intercalated disks and of the adherens junctions (AJs) in vascular endothelia. Now we report that using very sensitive new antibodies and drastic localization methods, we have also identified this protein as a component of the AJ plaques in simple and complex epithelia, in the adluminal cell layer of the transitional epithelium of the urinary tract and in certain cell layers of diverse stratified epithelia, including gingiva, tongue, pharynx and esophagus, cervix, vagina and epidermis. Myozap has not been identified in desmosomal and tight junction plaques. We have also detected protein myozap in AJ structures of carcinomas. The discovery of a novel major protein in AJ plaques now calls for re-examinations of molecular interactions in AJ formation and maintenance and also offers a new marker for diagnostic immunocytochemistry. We also discuss the need for progressive unravelling, extractive treatments and buffer rinses of sections and cultured cells to reveal obscured or masked antigens, before definitive negative conclusions in immunohistochemistry can be made.

BEND3 represses rDNA transcription by stabilizing a NoRC component via USP21 deubiquitinase

PubMed Central

Khan, Abid; Giri, Sumanprava; Wang, Yating; Chakraborty, Arindam; Ghosh, Archit K.; Anantharaman, Aparna; Aggarwal, Vasudha; Sathyan, Kizhakke M.; Ha, Taekjip; Prasanth, Kannanganattu V.; Prasanth, Supriya G.

2015-01-01

Ribosome biogenesis dictates the translational capacity of cells. Several mechanisms establish and maintain transcriptional output from eukaryotic ribosomal DNA (rDNA) loci. rDNA silencing is one such mechanism that ensures the inactivity and hence the maintenance of a silenced state of a subset of rRNA gene copies. Whereas oncogenic agents stimulate rRNA gene transcription, tumor suppressors decrease rRNA gene transcription. We demonstrate in mammalian cells that BANP, E5R, and Nac1 (BEN) domain 3 (BEND3), a quadruple BEN domain-containing protein, localizes in nucleoli and binds to ribosomal RNA gene promoters to help repress rRNA genes. Loss of BEND3 increases histone H3K4 trimethylation and, correspondingly, decreases rDNA promoter DNA methylation, consistent with a role for BEND3 in rDNA silencing. BEND3 associates with the nucleolar-remodeling complex (NoRC), and SUMOylated BEND3 stabilizes NoRC component TTF-1–interacting protein 5 via association with ubiquitin specific protease 21 (USP21) debiquitinase. Our results provide mechanistic insights into how the novel rDNA transcription repressor BEND3 acts together with NoRC to actively coordinate the establishment of rDNA silencing. PMID:26100909

BEND3 represses rDNA transcription by stabilizing a NoRC component via USP21 deubiquitinase.

PubMed

Khan, Abid; Giri, Sumanprava; Wang, Yating; Chakraborty, Arindam; Ghosh, Archit K; Anantharaman, Aparna; Aggarwal, Vasudha; Sathyan, Kizhakke M; Ha, Taekjip; Prasanth, Kannanganattu V; Prasanth, Supriya G

2015-07-07

Ribosome biogenesis dictates the translational capacity of cells. Several mechanisms establish and maintain transcriptional output from eukaryotic ribosomal DNA (rDNA) loci. rDNA silencing is one such mechanism that ensures the inactivity and hence the maintenance of a silenced state of a subset of rRNA gene copies. Whereas oncogenic agents stimulate rRNA gene transcription, tumor suppressors decrease rRNA gene transcription. We demonstrate in mammalian cells that BANP, E5R, and Nac1 (BEN) domain 3 (BEND3), a quadruple BEN domain-containing protein, localizes in nucleoli and binds to ribosomal RNA gene promoters to help repress rRNA genes. Loss of BEND3 increases histone H3K4 trimethylation and, correspondingly, decreases rDNA promoter DNA methylation, consistent with a role for BEND3 in rDNA silencing. BEND3 associates with the nucleolar-remodeling complex (NoRC), and SUMOylated BEND3 stabilizes NoRC component TTF-1-interacting protein 5 via association with ubiquitin specific protease 21 (USP21) debiquitinase. Our results provide mechanistic insights into how the novel rDNA transcription repressor BEND3 acts together with NoRC to actively coordinate the establishment of rDNA silencing.

Ergonomic design of crane cabins: a case study from a steel plant in India.

PubMed

Ray, Pradip Kumar; Tewari, V K

2012-01-01

The study, carried out at the Batch Annealing Furnace (BAF) shop of Cold Rolling Mill (CRM) at an integrated steel plant of India, concerns ergonomic evaluation and redesign of a manually-operated Electrical Overhead Travelling (EOT) crane cabin. The crane cabin is a complex worksystem consisting of the crane operator and twelve specific machine components embedded in a closed workspace. A crane operator has to perform various activities, such as loading and unloading of coils, setting and removal of convector plates, and routine maintenance work. Initially, an operator had to work in standing posture with bent back most of the time. Ergonomically poor design of the chair and the controls, awkward work postures, and insufficient vision angle resulting in musculoskeletal disorders (MSDs) are some of the critical problems observed.. The study, conceived as an industry-academia joint initiative, was undertaken by a design team, the members of which were drawn from both the company concerned and the institute. With the project executed successfully, a number of lessons, such as how to minimize the anthropometric mismatch, how to improve the layout of the components and controls within enclosed workspace, and how to improve work posture minimizing risk of MSDs have been learned.

E3 ubiquitin ligase Mule targets β-catenin under conditions of hyperactive Wnt signaling

PubMed Central

Dominguez-Brauer, Carmen; Khatun, Rahima; Elia, Andrew J.; Thu, Kelsie L.; Ramachandran, Parameswaran; Baniasadi, Shakiba P.; Hao, Zhenyue; Jones, Lisa D.; Haight, Jillian; Sheng, Yi; Mak, Tak W.

2017-01-01

Wnt signaling, named after the secreted proteins that bind to cell surface receptors to activate the pathway, plays critical roles both in embryonic development and the maintenance of homeostasis in many adult tissues. Two particularly important cellular programs orchestrated by Wnt signaling are proliferation and stem cell self-renewal. Constitutive activation of the Wnt pathway resulting from mutation or improper modulation of pathway components contributes to cancer development in various tissues. Colon cancers frequently bear inactivating mutations of the adenomatous polyposis coli (APC) gene, whose product is an important component of the destruction complex that regulates β-catenin levels. Stabilization and nuclear localization of β-catenin result in the expression of a panel of Wnt target genes. We previously showed that Mule/Huwe1/Arf-BP1 (Mule) controls murine intestinal stem and progenitor cell proliferation by modulating the Wnt pathway via c-Myc. Here we extend our investigation of Mule’s influence on oncogenesis by showing that Mule interacts directly with β-catenin and targets it for degradation under conditions of hyperactive Wnt signaling. Our findings suggest that Mule uses various mechanisms to fine-tune the Wnt pathway and provides multiple safeguards against tumorigenesis. PMID:28137882

E3 ubiquitin ligase Mule targets β-catenin under conditions of hyperactive Wnt signaling.

PubMed

Dominguez-Brauer, Carmen; Khatun, Rahima; Elia, Andrew J; Thu, Kelsie L; Ramachandran, Parameswaran; Baniasadi, Shakiba P; Hao, Zhenyue; Jones, Lisa D; Haight, Jillian; Sheng, Yi; Mak, Tak W

2017-02-14

Wnt signaling, named after the secreted proteins that bind to cell surface receptors to activate the pathway, plays critical roles both in embryonic development and the maintenance of homeostasis in many adult tissues. Two particularly important cellular programs orchestrated by Wnt signaling are proliferation and stem cell self-renewal. Constitutive activation of the Wnt pathway resulting from mutation or improper modulation of pathway components contributes to cancer development in various tissues. Colon cancers frequently bear inactivating mutations of the adenomatous polyposis coli ( APC ) gene, whose product is an important component of the destruction complex that regulates β-catenin levels. Stabilization and nuclear localization of β-catenin result in the expression of a panel of Wnt target genes. We previously showed that Mule/Huwe1/Arf-BP1 (Mule) controls murine intestinal stem and progenitor cell proliferation by modulating the Wnt pathway via c-Myc. Here we extend our investigation of Mule's influence on oncogenesis by showing that Mule interacts directly with β-catenin and targets it for degradation under conditions of hyperactive Wnt signaling. Our findings suggest that Mule uses various mechanisms to fine-tune the Wnt pathway and provides multiple safeguards against tumorigenesis.

CAD-supported university course on photonics and fiber optic communications

NASA Astrophysics Data System (ADS)

Chan, David K. C.; Richter, Andre

2002-05-01

The highly competitive global photonics industry has created a significant demand for professional Photonic Design Automation (PDA) tools and personnel trained to use them effectively. In such a dynamic field, CAD-supported courses built around widely used industrial PDA tools provide many advantages, especially when offered through tertiary education institutions (which are ideally suited to producing the future workforce of the Photonics industry). An objective of VPIsystems' University program is to develop tertiary level courses based on VPIsystems' WDM transmission and component modeling software tools. Advantages offered by such courses include: visualizing and aiding the understanding of complex physical problems encountered in the design of fiber-optic communication systems; virtual laboratory exercises that can accurately reproduce the behavior of real systems and components without the prohibitive infrastructure and maintenance costs of real laboratories; flexibility in studying interrelated physical effects individually or in combination to facilitate learning; provide expertise and practical insights in areas, including industry-focused topics, that are not generally covered in traditional tertiary courses; provide exposure to, currently, the most widely used PDA tools in the industry. In this paper, details of VPIsystems' University program and its CAD-supported Photonics courses will be presented.

Genetic surgery - a right strategy to attack cancer.

PubMed

Sverdlov, Eugene D

2011-12-01

The approaches now united under the term "gene therapy" can be divided into two broad strategies: (1) strategy using the ideology of molecular targeted therapy, but with genes in the role of agents targeted at certain molecular component(s) or pathways presumably crucial for cancer maintenance; (ii) strategy aimed at the destruction of tumors as a whole exploiting the features shared by all cancers, for example relatively fast mitotic cell division. While the first strategy is "true" gene therapy, the second one, as e.g. suicide gene therapy, is more like genetic surgery, when a surgeon just cuts off a tumor being not interested in subtle genetic mechanisms of cancer emergence and progression. This approach inherits the ideology of chemotherapy but escapes its severe toxic effects due to intracellular formation of toxic agents. Genetic surgery seems to be the most appropriate approach to combat cancer, and its simplicity is paradoxically adequate to the super-complexity of tumors. The review consists of three parts: (i) analysis of the reasons of tumor supercomplexity and fatally inevitable failure of molecular targeted therapy, (ii) general principles of the genetic surgery strategy, and (iii) examples of genetic surgery approaches with analysis of their drawbacks and the ways for their improvement.

RNAi-Based Suppressor Screens Reveal Genetic Interactions Between the CRL2LRR-1 E3-Ligase and the DNA Replication Machinery in Caenorhabditis elegans

PubMed Central

Ossareh-Nazari, Batool; Katsiarimpa, Anthi; Merlet, Jorge; Pintard, Lionel

2016-01-01

Cullin-RING E3-Ligases (CRLs), the largest family of E3 ubiquitin-Ligases, regulate diverse cellular processes by promoting ubiquitination of target proteins. The evolutionarily conserved Leucine Rich Repeat protein 1 (LRR-1) is a substrate-recognition subunit of a CRL2LRR-1 E3-ligase. Here we provide genetic evidence supporting a role of this E3-enzyme in the maintenance of DNA replication integrity in Caenorhabditis elegans. Through RNAi-based suppressor screens of lrr-1(0) and cul-2(or209ts) mutants, we identified two genes encoding components of the GINS complex, which is part of the Cdc45-MCM-GINS (CMG) replicative helicase, as well as CDC-7 and MUS-101, which drives the assembly of the CMG helicase during DNA replication. In addition, we identified the core components of the ATR/ATL-1 DNA replication checkpoint pathway (MUS-101, ATL-1, CLSP-1, CHK-1). These results suggest that the CRL2LRR-1 E3-ligase acts to modify or degrade factor(s) that would otherwise misregulate the replisome, eventually leading to the activation of the DNA replication checkpoint. PMID:27543292

Integrated Vehicle Health Management (IVHM) for Aerospace Systems

NASA Technical Reports Server (NTRS)

Baroth, Edmund C.; Pallix, Joan

2006-01-01

To achieve NASA's ambitious Integrated Space Transportation Program objectives, aerospace systems will implement a variety of new concept in health management. System level integration of IVHM technologies for real-time control and system maintenance will have significant impact on system safety and lifecycle costs. IVHM technologies will enhance the safety and success of complex missions despite component failures, degraded performance, operator errors, and environment uncertainty. IVHM also has the potential to reduce, or even eliminate many of the costly inspections and operations activities required by current and future aerospace systems. This presentation will describe the array of NASA programs participating in the development of IVHM technologies for NASA missions. Future vehicle systems will use models of the system, its environment, and other intelligent agents with which they may interact. IVHM will be incorporated into future mission planners, reasoning engines, and adaptive control systems that can recommend or execute commands enabling the system to respond intelligently in real time. In the past, software errors and/or faulty sensors have been identified as significant contributors to mission failures. This presentation will also address the development and utilization of highly dependable sohare and sensor technologies, which are key components to ensure the reliability of IVHM systems.

Structural Life and Reliability Metrics: Benchmarking and Verification of Probabilistic Life Prediction Codes

NASA Technical Reports Server (NTRS)

Litt, Jonathan S.; Soditus, Sherry; Hendricks, Robert C.; Zaretsky, Erwin V.

2002-01-01

Over the past two decades there has been considerable effort by NASA Glenn and others to develop probabilistic codes to predict with reasonable engineering certainty the life and reliability of critical components in rotating machinery and, more specifically, in the rotating sections of airbreathing and rocket engines. These codes have, to a very limited extent, been verified with relatively small bench rig type specimens under uniaxial loading. Because of the small and very narrow database the acceptance of these codes within the aerospace community has been limited. An alternate approach to generating statistically significant data under complex loading and environments simulating aircraft and rocket engine conditions is to obtain, catalog and statistically analyze actual field data. End users of the engines, such as commercial airlines and the military, record and store operational and maintenance information. This presentation describes a cooperative program between the NASA GRC, United Airlines, USAF Wright Laboratory, U.S. Army Research Laboratory and Australian Aeronautical & Maritime Research Laboratory to obtain and analyze these airline data for selected components such as blades, disks and combustors. These airline data will be used to benchmark and compare existing life prediction codes.

The ABPN Maintenance of Certification Program for psychiatrists: past history, current status, and future directions.

PubMed

Faulkner, Larry R; Tivnan, Patricia W; Winstead, Daniel K; Reus, Victor I; Andrade, Naleen N; Brooks, Beth Ann; Colenda, Christopher C; Mrazek, David A; Reifler, Burton V; Schneidman, Barbara

2008-01-01

To describe the American Board of Psychiatry and Neurology (ABPN) Maintenance of Certification Program, its underlying rationale, how it will be implemented now, and what it might look like in the future. The authors describe the philosophical foundation, specific components, and the implementation timeline of the ABPN Maintenance of Certification Program; the development of specific products that might be used by ABPN diplomates to meet its requirements; and several unanswered questions about its current status and future development. The ABPN Maintenance of Certification Program consists of specific requirements pertaining to professional standing, self-assessment and lifelong learning, performance in practice, and cognitive expertise that will be implemented incrementally over the next decade. The ABPN Maintenance of Certification Program has been implemented in a manner that is as consistent as possible with its underlying philosophical beliefs as well as the current and expected public and political concerns, diplomate needs, and the requirements of organizations responsible for licensure, credentialing, privileging, accreditation, professional development, and physician reimbursement.

e-Learning Content Design for Corrective Maintenance of Toshiba BMC 80.5 based on Knowledge Conversion using SECI Method: A Case Study in Aerospace Company

NASA Astrophysics Data System (ADS)

Permata Shabrina, Ayu; Pramuditya Soesanto, Rayinda; Kurniawati, Amelia; Teguh Kurniawan, Mochamad; Andrawina, Luciana

2018-03-01

Knowledge is a combination of experience, value, and information that is based on the intuition that allows an organization to evaluate and combine new information. In an organization, knowledge is not only attached to document but also in routine value creating activities, therefore knowledge is an important asset for the organization. X Corp is a company that focused on manufacturing aerospace components. In carrying out the production process, the company is supported by various machines, one of the machines is Toshiba BMC 80.5. The machine is used occasionally and therefore maintenance activity is needed, especially corrective maintenance. Corrective maintenance is done to make a breakdown machine back to work. Corrective maintenance is done by maintenance operator whose retirement year is close. The long term experience of the maintenance operator needs to be captured by the organization and shared across maintenance division. E-learning is one type of media that can support and assist knowledge sharing. This research purpose is to create the e-learning content for best practice of corrective maintenance activity for Toshiba BMC 80.5 by extracting the knowledge and experience from the operator based on knowledge conversion using SECI method. The knowledge source in this research is a maintenance supervisor and a senior maintenance engineer. From the evaluation of the e-learning content, it is known that the average test score of the respondents who use the e-learning increases from 77.5 to 87.5.

Relating Complexity and Error Rates of Ontology Concepts. More Complex NCIt Concepts Have More Errors.

PubMed

Min, Hua; Zheng, Ling; Perl, Yehoshua; Halper, Michael; De Coronado, Sherri; Ochs, Christopher

2017-05-18

Ontologies are knowledge structures that lend support to many health-information systems. A study is carried out to assess the quality of ontological concepts based on a measure of their complexity. The results show a relation between complexity of concepts and error rates of concepts. A measure of lateral complexity defined as the number of exhibited role types is used to distinguish between more complex and simpler concepts. Using a framework called an area taxonomy, a kind of abstraction network that summarizes the structural organization of an ontology, concepts are divided into two groups along these lines. Various concepts from each group are then subjected to a two-phase QA analysis to uncover and verify errors and inconsistencies in their modeling. A hierarchy of the National Cancer Institute thesaurus (NCIt) is used as our test-bed. A hypothesis pertaining to the expected error rates of the complex and simple concepts is tested. Our study was done on the NCIt's Biological Process hierarchy. Various errors, including missing roles, incorrect role targets, and incorrectly assigned roles, were discovered and verified in the two phases of our QA analysis. The overall findings confirmed our hypothesis by showing a statistically significant difference between the amounts of errors exhibited by more laterally complex concepts vis-à-vis simpler concepts. QA is an essential part of any ontology's maintenance regimen. In this paper, we reported on the results of a QA study targeting two groups of ontology concepts distinguished by their level of complexity, defined in terms of the number of exhibited role types. The study was carried out on a major component of an important ontology, the NCIt. The findings suggest that more complex concepts tend to have a higher error rate than simpler concepts. These findings can be utilized to guide ongoing efforts in ontology QA.

Modified Adaptive Control for Region 3 Operation in the Presence of Wind Turbine Structural Modes

NASA Technical Reports Server (NTRS)

Frost, Susan Alane; Balas, Mark J.; Wright, Alan D.

2010-01-01

Many challenges exist for the operation of wind turbines in an efficient manner that is reliable and avoids component fatigue and failure. Turbines operate in highly turbulent environments resulting in aerodynamic loads that can easily excite turbine structural modes, possibly causing component fatigue and failure. Wind turbine manufacturers are highly motivated to reduce component fatigue and failure that can lead to loss of revenue due to turbine down time and maintenance costs. The trend in wind turbine design is toward larger, more flexible turbines that are ideally suited to adaptive control methods due to the complexity and expense required to create accurate models of their dynamic characteristics. In this paper, we design an adaptive collective pitch controller for a high-fidelity simulation of a utility-scale, variable-speed horizontal axis wind turbine operating in Region 3. The objective of the adaptive pitch controller is to regulate generator speed, accommodate wind gusts, and reduce the excitation of structural modes in the wind turbine. The control objective is accomplished by collectively pitching the turbine blades. The adaptive collective pitch controller for Region 3 was compared in simulations with a baseline classical Proportional Integrator (PI) collective pitch controller. The adaptive controller will demonstrate the ability to regulate generator speed in Region 3, while accommodating gusts, and reducing the excitation of certain structural modes in the wind turbine.

Simulated driving and brain imaging: combining behavior, brain activity, and virtual reality.

PubMed

Carvalho, Kara N; Pearlson, Godfrey D; Astur, Robert S; Calhoun, Vince D

2006-01-01

Virtual reality in the form of simulated driving is a useful tool for studying the brain. Various clinical questions can be addressed, including both the role of alcohol as a modulator of brain function and regional brain activation related to elements of driving. We reviewed a study of the neural correlates of alcohol intoxication through the use of a simulated-driving paradigm and wished to demonstrate the utility of recording continuous-driving behavior through a new study using a programmable driving simulator developed at our center. Functional magnetic resonance imaging data was collected from subjects while operating a driving simulator. Independent component analysis (ICA) was used to analyze the data. Specific brain regions modulated by alcohol, and relationships between behavior, brain function, and alcohol blood levels were examined with aggregate behavioral measures. Fifteen driving epochs taken from two subjects while also recording continuously recorded driving variables were analyzed with ICA. Preliminary findings reveal that four independent components correlate with various aspects of behavior. An increase in braking while driving was found to increase activation in motor areas, while cerebellar areas showed signal increases during steering maintenance, yet signal decreases during steering changes. Additional components and significant findings are further outlined. In summary, continuous behavioral variables conjoined with ICA may offer new insight into the neural correlates of complex human behavior.

Interdependence of laminin-mediated clustering of lipid rafts and the dystrophin complex in astrocytes.

PubMed

Noël, Geoffroy; Tham, Daniel Kai Long; Moukhles, Hakima

2009-07-17

Astrocyte endfeet surrounding blood vessels are active domains involved in water and potassium ion transport crucial to the maintenance of water and potassium ion homeostasis in brain. A growing body of evidence points to a role for dystroglycan and its interaction with perivascular laminin in the targeting of the dystrophin complex and the water-permeable channel, aquaporin 4 (AQP4), at astrocyte endfeet. However, the mechanisms underlying such compartmentalization remain poorly understood. In the present study we found that AQP4 resided in Triton X-100-insoluble fraction, whereas dystroglycan was recovered in the soluble fraction in astrocytes. Cholesterol depletion resulted in the translocation of a pool of AQP4 to the soluble fraction indicating that its distribution is indeed associated with cholesterol-rich membrane domains. Upon laminin treatment AQP4 and the dystrophin complex, including dystroglycan, reorganized into laminin-associated clusters enriched for the lipid raft markers GM1 and flotillin-1 but not caveolin-1. Reduced diffusion rates of GM1 in the laminin-induced clusters were indicative of the reorganization of raft components in these domains. In addition, both cholesterol depletion and dystroglycan silencing reduced the number and area of laminin-induced clusters of GM1, AQP4, and dystroglycan. These findings demonstrate the interdependence between laminin binding to dystroglycan and GM1-containing lipid raft reorganization and provide novel insight into the dystrophin complex regulation of AQP4 polarization in astrocytes.

AUTOMOTIVE DIESEL MAINTENANCE 1. UNIT XXIX, REVIEWING THE CONSTRUCTION OF ENGINE COMPONENTS.

ERIC Educational Resources Information Center

Human Engineering Inst., Cleveland, OH.

THIS MODULE OF A 30-MODULE COURSE IS DESIGNED TO PROVIDE A REVIEW OF THE CONSTRUCTION AND OPERATION OF DIESEL ENGINE COMPONENTS. TOPICS ARE STATIONARY PARTS, ENGINE MOVING PARTS, PISTON RINGS, AND CONNECTING RODS AND PISTON PINS. THE MODULE CONSISTS OF AN INSTRUCTOR'S GUIDE, TRANSPARENCIES, A LIST OF SUGGESTED SUPPLEMENTARY MATERIALS, AND TRAINEE…

20. OVERVIEW OF SAR3 COMPLEX, SHOWING FORMER RESIDENTIAL AREA, SAR3 ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

20. OVERVIEW OF SAR-3 COMPLEX, SHOWING FORMER RESIDENTIAL AREA, SAR-3 SWITCH RACK, MAINTENANCE YARD, AND GREENSPOT BRIDGE. NOTE ALSO LARGE PIPE CONDUCTING TAILRACE WATER INTO IRRIGATION SYSTEM. VIEW TO SOUTHWEST. - Santa Ana River Hydroelectric System, Redlands, San Bernardino County, CA

Aging management program of the reactor building concrete at Point Lepreau Generating Station

NASA Astrophysics Data System (ADS)

Aldea, C.-M.; Shenton, B.; Demerchant, M. M.; Gendron, T.

2011-04-01

In order for New Brunswick Power Nuclear (NBPN) to control the risks of degradation of the concrete reactor building at the Point Lepreau Generating Station (PLGS) the development of an aging management plan (AMP) was initiated. The intention of this plan was to determine the requirements for specific structural components of concrete of the reactor building that require regular inspection and maintenance to ensure the safe and reliable operation of the plant. The document is currently in draft form and presents an integrated methodology for the application of an AMP for the concrete of the reactor building. The current AMP addresses the reactor building structure and various components, such as joint sealant and liners that are integral to the structure. It does not include internal components housed within the structure. This paper provides background information regarding the document developed and the strategy developed to manage potential degradation of the concrete of the reactor building, as well as specific programs and preventive and corrective maintenance activities initiated.

Methodology Development for Passive Component Reliability Modeling in a Multi-Physics Simulation Environment

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

Aldemir, Tunc; Denning, Richard; Catalyurek, Umit

Reduction in safety margin can be expected as passive structures and components undergo degradation with time. Limitations in the traditional probabilistic risk assessment (PRA) methodology constrain its value as an effective tool to address the impact of aging effects on risk and for quantifying the impact of aging management strategies in maintaining safety margins. A methodology has been developed to address multiple aging mechanisms involving large numbers of components (with possibly statistically dependent failures) within the PRA framework in a computationally feasible manner when the sequencing of events is conditioned on the physical conditions predicted in a simulation environment, suchmore » as the New Generation System Code (NGSC) concept. Both epistemic and aleatory uncertainties can be accounted for within the same phenomenological framework and maintenance can be accounted for in a coherent fashion. The framework accommodates the prospective impacts of various intervention strategies such as testing, maintenance, and refurbishment. The methodology is illustrated with several examples.« less

Improving the Reliability of Technological Subsystems Equipment for Steam Turbine Unit in Operation

NASA Astrophysics Data System (ADS)

Brodov, Yu. M.; Murmansky, B. E.; Aronson, R. T.

2017-11-01

The authors’ conception is presented of an integrated approach to reliability improving of the steam turbine unit (STU) state along with its implementation examples for the various STU technological subsystems. Basing on the statistical analysis of damage to turbine individual parts and components, on the development and application of modern methods and technologies of repair and on operational monitoring techniques, the critical components and elements of equipment are identified and priorities are proposed for improving the reliability of STU equipment in operation. The research results are presented of the analysis of malfunctions for various STU technological subsystems equipment operating as part of power units and at cross-linked thermal power plants and resulting in turbine unit shutdown (failure). Proposals are formulated and justified for adjustment of maintenance and repair for turbine components and parts, for condenser unit equipment, for regeneration subsystem and oil supply system that permit to increase the operational reliability, to reduce the cost of STU maintenance and repair and to optimize the timing and amount of repairs.

Systematic analysis of ECG predictors of sinus rhythm maintenance after electrical cardioversion for persistent atrial fibrillation.

PubMed

Lankveld, Theo; de Vos, Cees B; Limantoro, Ione; Zeemering, Stef; Dudink, Elton; Crijns, Harry J; Schotten, Ulrich

2016-05-01

Electrical cardioversion (ECV) is one of the rhythm control strategies in patients with persistent atrial fibrillation (AF). Unfortunately, recurrences of AF are common after ECV, which significantly limits the practical benefit of this treatment in patients with AF. The objectives of this study were to identify noninvasive complexity or frequency parameters obtained from the surface electrocardiogram (ECG) to predict sinus rhythm (SR) maintenance after ECV and to compare these ECG parameters with clinical predictors. We studied a wide variety of ECG-derived time- and frequency-domain AF complexity parameters in a prospective cohort of 502 patients with persistent AF referred for ECV. During 1-year follow-up, 161 patients (32%) maintained SR. The best clinical predictor of SR maintenance was antiarrhythmic drug (AAD) treatment. A model including clinical parameters predicted SR maintenance with a mean cross-validated area under the receiver operating characteristic curve (AUC) of 0.62 ± 0.05. The best single ECG parameter was the dominant frequency (DF) on lead V6. Combining several ECG parameters predicted SR maintenance with a mean AUC of 0.64 ± 0.06. Combining clinical and ECG parameters improved prediction to a mean AUC of 0.67 ± 0.05. Although the DF was affected by AAD treatment, excluding patients taking AADs did not significantly lower the predictive performance captured by the ECG. ECG-derived parameters predict SR maintenance during 1-year follow-up after ECV at least as good as known clinical predictors of rhythm outcome. The DF proved to be the most powerful ECG-derived predictor. Copyright © 2016 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

RT 6 - Software Intensive Systems Data Quality and Estimation Research in Support of Future Defense Cost Analysis

DTIC Science & Technology

2012-03-13

Brownfield Development 6.6.6 Agile and Kanban Development 6.6.7 Putting It All Together at the Large-Project or Enterprise Level 6.7 References 7...Ultrahigh software system assurance; Legacy maintenance and brownfield development; and Agile and kanban development. This chapter summarizes each...components or may need to be developed for special systems. Legacy Maintenance and Brownfield Development Fewer and fewer software-intensive systems have

Building Maintenance and Repair Data for Life-Cycle Cost Analyses: Electrical Systems.

DTIC Science & Technology

1991-05-01

Repair Data for Life-Cycle Cost Analyses: Electrical Systems by Edgar S. Neely Robert D. Neathammer James R. Stirn Robert P. Winkler This research...systems have been developed to assist planners in preparing DD Form 1391 documentation, designers in life-cycle cost component selection, and maintainers...Maintenance and Repair Data for Life-Cycle Cost Analyses: RDTE dated 1980 Electrical Systems REIMB 1984 - 1989 6. AUTH4OR(S) Edgar S. Neely, Robert D

Review of Maintenance and Repair Times for Components in Technological Facilities

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

L. C. Cadwallader

2012-11-01

This report is a compilation of some unique component repair time data and it also presents citations of more extensive reports where lists of repair times can be found. This collection of information should support analysts who seek to quantify maintainability and availability of high technology and nuclear energy production systems. While there are newer sources of repair time information, most, if not all, of the newer sources are proprietary and cannot be shared. This report offers data that, while older, is openly accessible and can serve as reasonable estimates of repair times, at least for initial studies. Some timesmore » were found for maintenance times in radiation environments, and some guidance for multiplicative factors to use to account for work in contamination areas.« less

Delay Choice vs. Delay Maintenance: Different Measures of Delayed Gratification in Capuchin Monkeys (Cebus apella)

PubMed Central

Addessi, Elsa; Paglieri, Fabio; Beran, Michael J.; Evans, Theodore A.; Macchitella, Luigi; De Petrillo, Francesca; Focaroli, Valentina

2013-01-01

Delaying gratification involves two components: (i) delay choice (selecting a delayed reward over an immediate one), and (ii) delay maintenance (sustaining the decision to delay gratification even if the immediate reward is available during the delay). In primates, two tasks most commonly have explored these components, the Intertemporal choice task and the Accumulation task. It is unclear whether these tasks provide equivalent measures of delay of gratification. Here, we compared the performance of the same capuchin monkeys, belonging to two study populations, between these tasks. We found only limited evidence of a significant correlation in performance. Consequently, in contrast to what is often assumed, our data provide only partial support to the hypothesis that these tasks provide equivalent measures of delay of gratification. PMID:23544770

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

Brown, Thomas

The design features developed for the Spherical Tokamak (ST) in the PPPL pilot plant study was used as the starting point in developing designs to meet the mission of a Fusion Nuclear Science Facility (FNSF) considering a range of machine sizes based on the influence of tritium consumption and maintenance strategies. The compact nature of a steady state operated ST device for this mission pushes operating conditions and places challenges in the design of components, device maintenance and the integration of supports and services. This paper reviews the general arrangement, design details and maintenance strategy of the ST-FNSF device coremore » for a 1.6-m and 1.0-m device; operating points which bracket the region between purchasing and breeding tritium.« less

Inhibitory Network Interactions Shape the Auditory Processing of Natural Communication Signals in the Songbird Auditory Forebrain

PubMed Central

Pinaud, Raphael; Terleph, Thomas A.; Tremere, Liisa A.; Phan, Mimi L.; Dagostin, André A.; Leão, Ricardo M.; Mello, Claudio V.; Vicario, David S.

2008-01-01

The role of GABA in the central processing of complex auditory signals is not fully understood. We have studied the involvement of GABAA-mediated inhibition in the processing of birdsong, a learned vocal communication signal requiring intact hearing for its development and maintenance. We focused on caudomedial nidopallium (NCM), an area analogous to parts of the mammalian auditory cortex with selective responses to birdsong. We present evidence that GABAA-mediated inhibition plays a pronounced role in NCM's auditory processing of birdsong. Using immunocytochemistry, we show that approximately half of NCM's neurons are GABAergic. Whole cell patch-clamp recordings in a slice preparation demonstrate that, at rest, spontaneously active GABAergic synapses inhibit excitatory inputs onto NCM neurons via GABAA receptors. Multi-electrode electrophysiological recordings in awake birds show that local blockade of GABAA-mediated inhibition in NCM markedly affects the temporal pattern of song-evoked responses in NCM without modifications in frequency tuning. Surprisingly, this blockade increases the phasic and largely suppresses the tonic response component, reflecting dynamic relationships of inhibitory networks that could include disinhibition. Thus processing of learned natural communication sounds in songbirds, and possibly other vocal learners, may depend on complex interactions of inhibitory networks. PMID:18480371

Where the thoughts dwell: the physiology of neuronal-glial "diffuse neural net".

PubMed

Verkhratsky, Alexei; Parpura, Vladimir; Rodríguez, José J

2011-01-07

The mechanisms underlying the production of thoughts by exceedingly complex cellular networks that construct the human brain constitute the most challenging problem of natural sciences. Our understanding of the brain function is very much shaped by the neuronal doctrine that assumes that neuronal networks represent the only substrate for cognition. These neuronal networks however are embedded into much larger and probably more complex network formed by neuroglia. The latter, although being electrically silent, employ many different mechanisms for intercellular signalling. It appears that astrocytes can control synaptic networks and in such a capacity they may represent an integral component of the computational power of the brain rather than being just brain "connective tissue". The fundamental question of whether neuroglia is involved in cognition and information processing remains, however, open. Indeed, a remarkable increase in the number of glial cells that distinguishes the human brain can be simply a result of exceedingly high specialisation of the neuronal networks, which delegated all matters of survival and maintenance to the neuroglia. At the same time potential power of analogue processing offered by internally connected glial networks may represent the alternative mechanism involved in cognition. Copyright © 2010 Elsevier B.V. All rights reserved.

A model of ecological and evolutionary consequences of color polymorphism.

PubMed

Forsman, Anders; Ahnesjö, Jonas; Caesar, Sofia; Karlsson, Magnus

2008-01-01

We summarize direct and indirect effects on fitness components of animal color pattern and present a synthesis of theories concerning the ecological and evolutionary dynamics of chromatic multiple niche polymorphisms. Previous endeavors have aimed primarily at identifying conditions that promote the evolution and maintenance of polymorphisms. We consider in a conceptual model also the reciprocal influence of color polymorphism on population processes and propose that polymorphism entails selective advantages that may promote the ecological success of polymorphic species. The model begins with an evolutionary branching event from mono- to polymorphic condition that, under the influence of correlational selection, is predicted to promote the evolution of physical integration of coloration and other traits (cf. multi-trait coevolution and complex phenotypes). We propose that the coexistence within a population of alternative ecomorphs with coadapted gene complexes promotes utilization of diverse environmental resources, population stability and persistence, colonization success, and range expansions, and enhances the evolutionary potential and speciation. Conversely, we predict polymorphic populations to be less vulnerable to environmental change and at lower risk of range contractions and extinctions compared with monomorphic populations. We offer brief suggestions as to how these falsifiable predictions may be tested.

The endosomal sorting complex required for transport (ESCRT) is required for the sensitivity of yeast cells to nickel ions in Saccharomyces cerevisiae.

PubMed

Luo, Chong; Cao, Chunlei; Jiang, Linghuo

2016-05-01

Nickel is one of the toxic environment metal pollutants and is linked to various human diseases. In this study, through a functional genomics approach we have identified 16 nickel-sensitive and 22 nickel-tolerant diploid deletion mutants of budding yeast genes, many of which are novel players in the regulation of nickel homeostasis. The 16 nickel-sensitive mutants are of genes mainly involved in the protein folding, modification and destination and the cellular transport processes, while the 22 nickel-tolerant mutants are of genes encoding components of ESCRT complexes as well as protein factors involved in both the cell wall integrity maintenance and the vacuolar protein sorting process. In consistence with their phenotypes, most of these nickel-sensitive mutants show reduced intracellular nickel contents, while the majority of these nickel-tolerant mutants show elevated intracellular nickel contents, as compared to the wild type in response to nickel stress. Our data provides a basis for our understanding the regulation of nickel homeostasis and molecular mechanisms of nickel-induced human pathogenesis. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

MCM Paradox: Abundance of Eukaryotic Replicative Helicases and Genomic Integrity.

PubMed

Das, Mitali; Singh, Sunita; Pradhan, Satyajit; Narayan, Gopeshwar

2014-01-01

As a crucial component of DNA replication licensing system, minichromosome maintenance (MCM) 2-7 complex acts as the eukaryotic DNA replicative helicase. The six related MCM proteins form a heterohexamer and bind with ORC, CDC6, and Cdt1 to form the prereplication complex. Although the MCMs are well known as replicative helicases, their overabundance and distribution patterns on chromatin present a paradox called the "MCM paradox." Several approaches had been taken to solve the MCM paradox and describe the purpose of excess MCMs distributed beyond the replication origins. Alternative functions of these MCMs rather than a helicase had also been proposed. This review focuses on several models and concepts generated to solve the MCM paradox coinciding with their helicase function and provides insight into the concept that excess MCMs are meant for licensing dormant origins as a backup during replication stress. Finally, we extend our view towards the effect of alteration of MCM level. Though an excess MCM constituent is needed for normal cells to withstand stress, there must be a delineation of the threshold level in normal and malignant cells. This review also outlooks the future prospects to better understand the MCM biology.

MCM Paradox: Abundance of Eukaryotic Replicative Helicases and Genomic Integrity

PubMed Central

Das, Mitali; Singh, Sunita; Pradhan, Satyajit

2014-01-01

As a crucial component of DNA replication licensing system, minichromosome maintenance (MCM) 2–7 complex acts as the eukaryotic DNA replicative helicase. The six related MCM proteins form a heterohexamer and bind with ORC, CDC6, and Cdt1 to form the prereplication complex. Although the MCMs are well known as replicative helicases, their overabundance and distribution patterns on chromatin present a paradox called the “MCM paradox.” Several approaches had been taken to solve the MCM paradox and describe the purpose of excess MCMs distributed beyond the replication origins. Alternative functions of these MCMs rather than a helicase had also been proposed. This review focuses on several models and concepts generated to solve the MCM paradox coinciding with their helicase function and provides insight into the concept that excess MCMs are meant for licensing dormant origins as a backup during replication stress. Finally, we extend our view towards the effect of alteration of MCM level. Though an excess MCM constituent is needed for normal cells to withstand stress, there must be a delineation of the threshold level in normal and malignant cells. This review also outlooks the future prospects to better understand the MCM biology. PMID:25386362

Conditional mutation of Smc5 in mouse embryonic stem cells perturbs condensin localization and mitotic progression.

PubMed

Pryzhkova, Marina V; Jordan, Philip W

2016-04-15

Correct duplication of stem cell genetic material and its appropriate segregation into daughter cells are requisites for tissue, organ and organism homeostasis. Disruption of stem cell genomic integrity can lead to developmental abnormalities and cancer. Roles of the Smc5/6 structural maintenance of chromosomes complex in pluripotent stem cell genome maintenance have not been investigated, despite its important roles in DNA synthesis, DNA repair and chromosome segregation as evaluated in other model systems. Using mouse embryonic stem cells (mESCs) with a conditional knockout allele of Smc5, we showed that Smc5 protein depletion resulted in destabilization of the Smc5/6 complex, accumulation of cells in G2 phase of the cell cycle and apoptosis. Detailed assessment of mitotic mESCs revealed abnormal condensin distribution and perturbed chromosome segregation, accompanied by irregular spindle morphology, lagging chromosomes and DNA bridges. Mutation of Smc5 resulted in retention of Aurora B kinase and enrichment of condensin on chromosome arms. Furthermore, we observed reduced levels of Polo-like kinase 1 at kinetochores during mitosis. Our study reveals crucial requirements of the Smc5/6 complex during cell cycle progression and for stem cell genome maintenance. © 2016. Published by The Company of Biologists Ltd.

Succinate Dehydrogenase Mutation Underlies Global Epigenomic Divergence in Gastrointestinal Stromal Tumor

PubMed Central

Killian, J. Keith; Kim, Su Young; Miettinen, Markku; Smith, Carly; Merino, Maria; Tsokos, Maria; Quezado, Martha; Smith, William I.; Jahromi, Mona S.; Xekouki, Paraskevi; Szarek, Eva; Walker, Robert L.; Lasota, Jerzy; Raffeld, Mark; Klotzle, Brandy; Wang, Zengfeng; Jones, Laura; Zhu, Yuelin; Wang, Yonghong; Waterfall, Joshua J.; O’Sullivan, Maureen J.; Bibikova, Marina; Pacak, Karel; Stratakis, Constantine; Janeway, Katherine A.; Schiffman, Joshua D.; Fan, Jian-Bing; Helman, Lee; Meltzer, Paul S.

2014-01-01

Gastrointestinal stromal tumors (GIST) harbor driver mutations of signal transduction kinases such as KIT, or, alternatively, manifest loss-of-function defects in the mitochondrial succinate dehydrogenase (SDH) complex, a component of the Krebs cycle and electron transport chain. We have uncovered a striking divergence between the DNA methylation profiles of SDH-deficient GIST (n = 24) versus KIT tyrosine kinase pathway–mutated GIST (n = 39). Infinium 450K methylation array analysis of formalin-fixed paraffin-embedded tissues disclosed an order of magnitude greater genomic hypermethylation relative to SDH-deficient GIST versus the KIT-mutant group (84.9 K vs. 8.4 K targets). Epigenomic divergence was further found among SDH-mutant paraganglioma/pheochromocytoma (n = 29), a developmentally distinct SDH-deficient tumor system. Comparison of SDH -mutant GIST with isocitrate dehydrogenase -mutant glioma, another Krebs cycle–defective tumor type, revealed comparable measures of global hypo- and hypermethylation. These data expose a vital connection between succinate metabolism and genomic DNA methylation during tumorigenesis, and generally implicate the mitochondrial Krebs cycle in nuclear epigenomic maintenance. SIGNIFICANCE This study shows that SDH deficiency underlies pervasive DNA hypermethylation in multiple tumor lineages, generally defining the Krebs cycle as mitochondrial custodian of the methylome. We propose that this phenomenon may result from a failure of maintenance CpG demethylation, secondary to inhibition of the TET 5-methylcytosine dioxgenase demethylation pathway, by inhibitory metabolites that accumulate in tumors with Krebs cycle dysfunction. PMID:23550148

Health care delivery system for long duration manned space operations

NASA Technical Reports Server (NTRS)

Logan, J. S.; Shulman, E. L.; Johnson, P. C.

1983-01-01

Specific requirements for medical support of a long-duration manned facility in a low earth orbit derive from inflight medical experience, projected medical scenarios, mission related spacecraft and environmental hazards, health maintenance, and preventive medicine. A sequential buildup of medical capabilities tailored to increasing mission complexity is proposed. The space station health maintenance facility must provide preventive, diagnostic, and therapeutic medical support as immediate rescue capability may not exist.

The Conception, Construction, and Maintenance of the Identity of Roman Catholic Female Religious Teachers: A Historical Case Study from Ireland

ERIC Educational Resources Information Center

O'Donoghue, Tom; Harford, Judith

2014-01-01

Over the last three decades, there has been a burgeoning of research on teacher identity. While the various bodies of work produced are very valuable, further lines of enquiry need to be pursued in order to take account of the complexities involved. This paper on the conception, construction, and maintenance of the identity of Roman Catholic…

29. OVERVIEW OF SAR3 COMPLEX, LOOKING NORTHEAST. FROM LEFT TO ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

29. OVERVIEW OF SAR-3 COMPLEX, LOOKING NORTHEAST. FROM LEFT TO RIGHT, THE STRUCTURES ARE THE SAR-3 POWERHOUSE, SWITCHRACK, OFFICE (IN BACKGROUND), WAREHOUSE, CARPENTER SHOP, MAINTENANCE YARD, STORAGE BUILDING, AND STORAGE GARAGE (IN BACKGROUND). - Santa Ana River Hydroelectric System, Redlands, San Bernardino County, CA

Salience of working-memory maintenance and manipulation deficits in schizophrenia

PubMed Central

Hill, S. K.; Griffin, G. B.; Miura, T. Kazuto; Herbener, E. S.; Sweeney, J. A.

2011-01-01

Background Encoding and maintenance of information in working memory, followed by internal manipulation of that information for planning adaptive behavior, are two key components of working-memory systems. Both processes have been reported to be impaired in schizophrenia, but few studies have directly compared the relative severity of these abnormalities, or the degree to which manipulation deficits might be secondary to alterations in maintenance processes. Method Clinically stable schizophrenia patients (n=25) and a demographically similar healthy comparison group (n=24) were administered a verbal span task with three levels of working-memory load. Maintenance was assessed using sequential position questions. Manipulation processes were assessed by requiring comparison of the relative sequential position of test items, which entailed simultaneous serial search strategies regarding item order. Results Both groups showed reduced accuracy and increased reaction time for manipulation compared with maintenance processing. There were significant patient impairments across working-memory loads. There was no differential deficit in manipulation processing, and effect sizes of relative deficit in the patient group were higher for maintenance than manipulation processing. Conclusions The strong correlation for maintenance and manipulation deficits suggest that impairments in the ability to internally manipulate information stored in working-memory systems are not greater than alterations in the encoding and maintaining of information in working memory and that disturbances in maintenance processing may contribute to deficits in higher-order working-memory operations. PMID:20214839

Operational Interventions to Maintenance Error

NASA Technical Reports Server (NTRS)

Kanki, Barbara G.; Walter, Diane; Dulchinos, VIcki

1997-01-01

A significant proportion of aviation accidents and incidents are known to be tied to human error. However, research of flight operational errors has shown that so-called pilot error often involves a variety of human factors issues and not a simple lack of individual technical skills. In aircraft maintenance operations, there is similar concern that maintenance errors which may lead to incidents and accidents are related to a large variety of human factors issues. Although maintenance error data and research are limited, industry initiatives involving human factors training in maintenance have become increasingly accepted as one type of maintenance error intervention. Conscientious efforts have been made in re-inventing the team7 concept for maintenance operations and in tailoring programs to fit the needs of technical opeRAtions. Nevertheless, there remains a dual challenge: 1) to develop human factors interventions which are directly supported by reliable human error data, and 2) to integrate human factors concepts into the procedures and practices of everyday technical tasks. In this paper, we describe several varieties of human factors interventions and focus on two specific alternatives which target problems related to procedures and practices; namely, 1) structured on-the-job training and 2) procedure re-design. We hope to demonstrate that the key to leveraging the impact of these solutions comes from focused interventions; that is, interventions which are derived from a clear understanding of specific maintenance errors, their operational context and human factors components.

Reduction of Maintenance Error Through Focused Interventions

NASA Technical Reports Server (NTRS)

Kanki, Barbara G.; Walter, Diane; Rosekind, Mark R. (Technical Monitor)

1997-01-01

It is well known that a significant proportion of aviation accidents and incidents are tied to human error. In flight operations, research of operational errors has shown that so-called "pilot error" often involves a variety of human factors issues and not a simple lack of individual technical skills. In aircraft maintenance operations, there is similar concern that maintenance errors which may lead to incidents and accidents are related to a large variety of human factors issues. Although maintenance error data and research are limited, industry initiatives involving human factors training in maintenance have become increasingly accepted as one type of maintenance error intervention. Conscientious efforts have been made in re-inventing the "team" concept for maintenance operations and in tailoring programs to fit the needs of technical operations. Nevertheless, there remains a dual challenge: to develop human factors interventions which are directly supported by reliable human error data, and to integrate human factors concepts into the procedures and practices of everyday technical tasks. In this paper, we describe several varieties of human factors interventions and focus on two specific alternatives which target problems related to procedures and practices; namely, 1) structured on-the-job training and 2) procedure re-design. We hope to demonstrate that the key to leveraging the impact of these solutions comes from focused interventions; that is, interventions which are derived from a clear understanding of specific maintenance errors, their operational context and human factors components.

Navy Additive Manufacturing: Adding Parts, Subtracting Steps

DTIC Science & Technology

2015-06-01

complex weapon systems within designed specifications requires extensive routine and preventative maintenance as well as expeditious repairs when...failures occur. These repairs are sometimes complex and often unpredictable in both peace and wartime environments. To keep these weapon systems...basis. The solution is not a simple one, but rather one of high complexity that cannot just be adopted from a big-box store such as Walmart, Target

Stn1-Ten1 is an Rpa2-Rpa3-like complex at telomeres

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

Sun, Jia; Yu, Eun Young; Yang, Yuting

2010-09-02

In budding yeast, Cdc13, Stn1, and Ten1 form a heterotrimeric complex (CST) that is essential for telomere protection and maintenance. Previous bioinformatics analysis revealed a putative oligonucleotide/oligosaccharide-binding (OB) fold at the N terminus of Stn1 (Stn1N) that shows limited sequence similarity to the OB fold of Rpa2, a subunit of the eukaryotic ssDNA-binding protein complex replication protein A (RPA). Here we present functional and structural analyses of Stn1 and Ten1 from multiple budding and fission yeast. The crystal structure of the Candida tropicalis Stn1N complexed with Ten1 demonstrates an Rpa2N-Rpa3-like complex. In both structures, the OB folds of the twomore » components pack against each other through interactions between two C-terminal helices. The structure of the C-terminal domain of Saccharomyces cerevisiae Stn1 (Stn1C) was found to comprise two related winged helix-turn-helix (WH) motifs, one of which is most similar to the WH motif at the C terminus of Rpa2, again supporting the notion that Stn1 resembles Rpa2. The crystal structure of the fission yeast Schizosaccharomyces pombe Stn1N-Ten1 complex exhibits a virtually identical architecture as the C. tropicalis Stn1N-Ten1. Functional analyses of the Candida albicans Stn1 and Ten1 proteins revealed critical roles for these proteins in suppressing aberrant telomerase and recombination activities at telomeres. Mutations that disrupt the Stn1-Ten1 interaction induce telomere uncapping and abolish the telomere localization of Ten1. Collectively, our structural and functional studies illustrate that, instead of being confined to budding yeast telomeres, the CST complex may represent an evolutionarily conserved RPA-like telomeric complex at the 3' overhangs that works in parallel with or instead of the well-characterized POT1-TPP1/TEBP{alpha}-{beta} complex.« less

Using the intervention mapping protocol to develop a maintenance programme for the SLIMMER diabetes prevention intervention.

PubMed

Elsman, Ellen B M; Leerlooijer, Joanne N; Ter Beek, Josien; Duijzer, Geerke; Jansen, Sophia C; Hiddink, Gerrit J; Feskens, Edith J M; Haveman-Nies, Annemien

2014-10-27

Although lifestyle interventions have shown to be effective in reducing the risk for type 2 diabetes mellitus, maintenance of achieved results is difficult, as participants often experience relapse after the intervention has ended. This paper describes the systematic development of a maintenance programme for the extensive SLIMMER intervention, an existing diabetes prevention intervention for high-risk individuals, implemented in a real-life setting in the Netherlands. The maintenance programme was developed using the Intervention Mapping protocol. Programme development was informed by a literature study supplemented by various focus group discussions and feedback from implementers of the extensive SLIMMER intervention. The maintenance programme was designed to sustain a healthy diet and physical activity pattern by targeting knowledge, attitudes, subjective norms and perceived behavioural control of the SLIMMER participants. Practical applications were clustered into nine programme components, including sports clinics at local sports clubs, a concluding meeting with the physiotherapist and dietician, and a return session with the physiotherapist, dietician and physical activity group. Manuals were developed for the implementers and included a detailed time table and step-by-step instructions on how to implement the maintenance programme. The Intervention Mapping protocol provided a useful framework to systematically plan a maintenance programme for the extensive SLIMMER intervention. The study showed that planning a maintenance programme can build on existing implementation structures of the extensive programme. Future research is needed to determine to what extent the maintenance programme contributes to sustained effects in participants of lifestyle interventions.

Open-RAC: Open-Design, Recirculating and Auto-Cleaning Zebrafish Maintenance System.

PubMed

Nema, Shubham; Bhargava, Yogesh

2017-08-01

Zebrafish is a vertebrate animal model. Their maintenance in large number under laboratory conditions is a daunting task. Commercially available recirculating zebrafish maintenance systems are used to efficiently handle the tasks of automatic sediment cleaning from zebrafish tanks with minimal waste of water. Due to their compact nature, they also ensure the maximal use of available lab space. However, the high costs of commercial systems present a limitation to researchers with limited funds. A cost-effective zebrafish maintenance system with major features offered by commercially available systems is highly desirable. Here, we describe a compact and recirculating zebrafish maintenance system. Our system is composed of cost-effective components, which are available in local markets and/or can be procured via online vendors. Depending on the expertise of end users, the system can be assembled in 2 days. The system is completely customizable as it offers geometry independent zebrafish tanks that are capable of auto-cleaning the sediments. Due to these features, we called our setup as Open-RAC (Open-design, Recirculating and Auto-Cleaning zebrafish maintenance system). Open-RAC is a cost-effective and viable alternative to the currently available zebrafish maintenance systems. Thus, we believe that the use of Open-RAC could promote the zebrafish research by removing the cost barrier for researchers.

KSC-2011-1398

NASA Image and Video Library

2011-02-08

CAPE CANAVERAL, Fla. -- A traditional ribbon-cutting ceremony takes place inside the new 18,500-square-foot Electrical Maintenance Facility (EMF) at NASA's Kennedy Space Center in Florida. From left are Kennedy Director of Operations Mike Benik, NASA Construction of Facility Project Manager Nick Rivieccio and Kennedy Center Director Bob Cabana. Located in Kennedy's Launch Complex 39 area, the EMF will provide new and renovated space for maintenance shops, offices, and equipment and material storage in support of the electrical maintenance functions for the center. The facility is projected to receive Gold certification under the U.S. Green Building Council’s Leadership in Energy and Environmental Design (LEED) rating system. Photo credit: NASA/ Troy Cryder

Validation of Helicopter Gear Condition Indicators Using Seeded Fault Tests

NASA Technical Reports Server (NTRS)

Dempsey, Paula; Brandon, E. Bruce

2013-01-01

A "seeded fault test" in support of a rotorcraft condition based maintenance program (CBM), is an experiment in which a component is tested with a known fault while health monitoring data is collected. These tests are performed at operating conditions comparable to operating conditions the component would be exposed to while installed on the aircraft. Performance of seeded fault tests is one method used to provide evidence that a Health Usage Monitoring System (HUMS) can replace current maintenance practices required for aircraft airworthiness. Actual in-service experience of the HUMS detecting a component fault is another validation method. This paper will discuss a hybrid validation approach that combines in service-data with seeded fault tests. For this approach, existing in-service HUMS flight data from a naturally occurring component fault will be used to define a component seeded fault test. An example, using spiral bevel gears as the targeted component, will be presented. Since the U.S. Army has begun to develop standards for using seeded fault tests for HUMS validation, the hybrid approach will be mapped to the steps defined within their Aeronautical Design Standard Handbook for CBM. This paper will step through their defined processes, and identify additional steps that may be required when using component test rig fault tests to demonstrate helicopter CI performance. The discussion within this paper will provide the reader with a better appreciation for the challenges faced when defining a seeded fault test for HUMS validation.

Maintenance Chemotherapy for Advanced Non–Small-Cell Lung Cancer: New Life for an Old Idea

PubMed Central

Gerber, David E.; Schiller, Joan H.

2013-01-01

Although well established for the treatment of certain hematologic malignancies, maintenance therapy has only recently become a treatment paradigm for advanced non–small-cell lung cancer. Maintenance therapy, which is designed to prolong a clinically favorable state after completion of a predefined number of induction chemotherapy cycles, has two principal paradigms. Continuation maintenance therapy entails the ongoing administration of a component of the initial chemotherapy regimen, generally the nonplatinum cytotoxic drug or a molecular targeted agent. With switch maintenance (also known as sequential therapy), a new and potentially non–cross-resistant agent is introduced immediately on completion of first-line chemotherapy. Potential rationales for maintenance therapy include increased exposure to effective therapies, decreasing chemotherapy resistance, optimizing efficacy of chemotherapeutic agents, antiangiogenic effects, and altering antitumor immunity. To date, switch maintenance therapy strategies with pemetrexed and erlotinib have demonstrated improved overall survival, resulting in US Food and Drug Administration approval for this indication. Recently, continuation maintenance with pemetrexed was found to prolong overall survival as well. Factors predicting benefit from maintenance chemotherapy include the degree of response to first-line therapy, performance status, the likelihood of receiving further therapy at the time of progression, and tumor histology and molecular characteristics. Several aspects of maintenance therapy have raised considerable debate in the thoracic oncology community, including clinical trial end points, the prevalence of second-line chemotherapy administration, the role of treatment-free intervals, quality of life, economic considerations, and whether progression-free survival is a worthy therapeutic goal in this disease setting. PMID:23401441

Dual role of wingless signaling in stem-like hematopoietic precursor maintenance in Drosophila.

PubMed

Sinenko, Sergey A; Mandal, Lolitika; Martinez-Agosto, Julian A; Banerjee, Utpal

2009-05-01

In Drosophila, blood development occurs in a specialized larval hematopoietic organ, the lymph gland (LG), within which stem-like hemocyte precursors or prohemocytes differentiate to multiple blood cell types. Here we show that components of the Wingless (Wg) signaling pathway are expressed in prohemocytes. Loss- and gain-of-function analysis indicates that canonical Wg signaling is required for maintenance of prohemocytes and negatively regulates their differentiation. Wg signals locally in a short-range fashion within different compartments of the LG. In addition, Wg signaling positively regulates the proliferation and maintenance of cells that function as a hematopoietic niche in Drosophila, the posterior signaling center (PSC), and in the proliferation of crystal cells. Our studies reveal a conserved function of Wg signaling in the maintenance of stem-like blood progenitors and reveal an involvement of this pathway in the regulation of hemocyte differentiation through its action in the hematopoietic niche.

A Capacity Forecast Model for Volatile Data in Maintenance Logistics

NASA Astrophysics Data System (ADS)

Berkholz, Daniel

2009-05-01

Maintenance, repair and overhaul processes (MRO processes) are elaborate and complex. Rising demands on these after sales services require reliable production planning and control methods particularly for maintaining valuable capital goods. Downtimes lead to high costs and an inability to meet delivery due dates results in severe contract penalties. Predicting the required capacities for maintenance orders in advance is often difficult due to unknown part conditions unless the goods are actually inspected. This planning uncertainty results in extensive capital tie-up by rising stock levels within the whole MRO network. The article outlines an approach to planning capacities when maintenance data forecasting is volatile. It focuses on the development of prerequisites for a reliable capacity planning model. This enables a quick response to maintenance orders by employing appropriate measures. The information gained through the model is then systematically applied to forecast both personnel capacities and the demand for spare parts. The improved planning reliability can support MRO service providers in shortening delivery times and reducing stock levels in order to enhance the performance of their maintenance logistics.

Qualitative Analysis for Maintenance Process Assessment

NASA Technical Reports Server (NTRS)

Brand, Lionel; Kim, Yong-Mi; Melo, Walcelio; Seaman, Carolyn; Basili, Victor

1996-01-01

In order to improve software maintenance processes, we first need to be able to characterize and assess them. These tasks must be performed in depth and with objectivity since the problems are complex. One approach is to set up a measurement-based software process improvement program specifically aimed at maintenance. However, establishing a measurement program requires that one understands the problems to be addressed by the measurement program and is able to characterize the maintenance environment and processes in order to collect suitable and cost-effective data. Also, enacting such a program and getting usable data sets takes time. A short term substitute is therefore needed. We propose in this paper a characterization process aimed specifically at maintenance and based on a general qualitative analysis methodology. This process is rigorously defined in order to be repeatable and usable by people who are not acquainted with such analysis procedures. A basic feature of our approach is that actual implemented software changes are analyzed in order to understand the flaws in the maintenance process. Guidelines are provided and a case study is shown that demonstrates the usefulness of the approach.