Science.gov

Sample records for mitigating resisting forces

  1. CORRELATION OF AIRWAY RESISTANCE WITH FORCED RANDOM NOISE RESISTANCE PARAMETERS

    EPA Science Inventory

    The correlation between airway resistance (RAW) measured in a plethysmograph and three respiratory resistance parameters measured by forced random noise was evaluated. Forced random noise resistance parameters were the average resistance between 5 and 9 Hz (R5-9), the average res...

  2. Mitigated-force carriage for high magnetic field environments

    SciTech Connect

    Ludtka, Gerard M.; Ludtka, Gail M.; Wilgen, John B.; Murphy, Bart L.

    2015-05-19

    A carriage for high magnetic field environments includes a plurality of work-piece separators disposed in an operable relationship with a work-piece processing magnet having a magnetic field strength of at least 1 Tesla for supporting and separating a plurality of work-pieces by a preselected, essentially equal spacing, so that, as a first work-piece is inserted into the magnetic field, a second work-piece is simultaneously withdrawn from the magnetic field, so that an attractive magnetic force imparted on the first work-piece offsets a resistive magnetic force imparted on the second work-piece.

  3. Mitigated-force carriage for high magnetic field environments

    DOEpatents

    Ludtka, Gerard M; Ludtka, Gail M; Wilgen, John B; Murphy, Bart L

    2014-05-20

    A carriage for high magnetic field environments includes a first work-piece holding means for holding a first work-piece, the first work-piece holding means being disposed in an operable relationship with a work-piece processing magnet having a magnetic field strength of at least 1 Tesla. The first work-piece holding means is further disposed in operable connection with a second work-piece holding means for holding a second work-piece so that, as the first work-piece is inserted into the magnetic field, the second work-piece is simultaneously withdrawn from the magnetic field, so that an attractive magnetic force imparted on the first work-piece offsets a resistive magnetic force imparted on the second work-piece.

  4. A Constant-Force Resistive Exercise Unit

    NASA Technical Reports Server (NTRS)

    Colosky, Paul; Ruttley, Tara

    2010-01-01

    A constant-force resistive exercise unit (CFREU) has been invented for use in both normal gravitational and microgravitational environments. In comparison with a typical conventional exercise machine, this CFREU weighs less and is less bulky: Whereas weight plates and associated bulky supporting structures are used to generate resistive forces in typical conventional exercise machines, they are not used in this CFREU. Instead, resistive forces are generated in this CFREU by relatively compact, lightweight mechanisms based on constant-torque springs wound on drums. Each such mechanism is contained in a module, denoted a resistive pack, that includes a shaft for making a torque connection to a cable drum. During a stroke of resistive exercise, the cable is withdrawn from the cable drum against the torque exerted by the resistance pack. The CFREU includes a housing, within which can be mounted one or more resistive pack(s). The CFREU also includes mechanisms for engaging any combination of (1) one or more resistive pack(s) and (2) one or more spring(s) within each resistive pack to obtain a desired level of resistance.

  5. Resistive force theory for sand swimming

    NASA Astrophysics Data System (ADS)

    Ding, Yang; Maladen, Ryan; Li, Chen; Goldman, Daniel

    2009-11-01

    We discuss a resistive force theoryfootnotetextMaladen et. al, Science, 325, 314, 2009 that predicts the ratio of forward speed to wave speed (wave efficiency, η) of the sandfish lizard as it swims in granular media of varying volume fraction φ using a sinusoidal traveling wave body motion. In experiment η 0.5 independent of φ and is intermediate between η 0.2 for low Re Newtonian fluid undulatory swimmers like nematodes and η 0.9 for undulatory locomotion on a deformable surface. To predict η in granular media, we developed a resistive force model which balances thrust and drag force over the animal profile. We approximate the drag forces by measuring the force on a cylinder (a ``segment'' of the sandfish) oriented at different angles relative to the displacement direction. The model correctly predicts that η is independent of φ because the ratio of thrust to drag is independent of φ. The thrust component of the drag force is relatively larger in granular media than in low Re fluids, which explains why η in frictional granular media is greater than in viscous fluids.

  6. Resistive force theory for sand swimming

    NASA Astrophysics Data System (ADS)

    Ding, Yang; Maladen, Ryan; Li, Chen; Goldman, Daniel

    2009-11-01

    We discuss a resistive force theory footnotetextMaladen et. al, Science, 325, 314, 2009 that predicts the ratio of forward speed to wave speed (wave efficiency, η) of the sandfish lizard as it swims in granular media of varying volume fraction φ using a sinusoidal traveling wave body motion. In experiment η 0.5 independent of φ and is intermediate between η 0.2 for low Re Newtonian fluid undulatory swimmers like nematodes and η 0.9 for undulatory locomotion on a deformable surface. To predict η in granular media, we developed a resistive force model which balances thrust and drag force over the animal profile. We approximate the drag forces by measuring the force on a cylinder (a ``segment'' of the sandfish) oriented at different angles relative to the displacement direction. The model correctly predicts that η is independent of φ because the ratio of thrust to drag is independent of φ. The thrust component of the drag force is relatively larger in granular media than in low Re fluids, which explains why η in frictional granular media is greater than in viscous fluids.

  7. Mitigating Resistance to Teaching Science Through Inquiry: Studying Self

    NASA Astrophysics Data System (ADS)

    Spector, Barbara; Burkett, Ruth S.; Leard, Cyndy

    2007-04-01

    This is the report of a qualitative emergent-design study of 2 different Web-enhanced science methods courses for preservice elementary teachers in which an experiential learning strategy, labeled “using yourself as a learning laboratory,” was implemented. Emergent grounded theory indicated this strategy, when embedded in a course organized as an inquiry with specified action foci, contributed to mitigating participants’ resistance to learning and teaching through inquiry. Enroute to embracing inquiry, learners experienced stages resembling the stages of grief one experiences after a major loss. Data sources included participant observation, electronic artifacts in WebCT, and interviews. Findings are reported in 3 major sections: “Action Foci Common to Both Courses,” “Participants’ Growth and Change,” and “Challenges and Tradeoffs.”

  8. Aligned composite structures for mitigation of impact damage and resistance to wear in dynamic environments

    DOEpatents

    Mulligan, Anthony C.; Rigali, Mark J.; Sutaria, Manish P.; Popovich, Dragan; Halloran, Joseph P.; Fulcher, Michael L.; Cook, Randy C.

    2005-12-13

    Fibrous monolith composites having architectures that provide increased flaw insensitivity, improved hardness, wear resistance and damage tolerance and methods of manufacture thereof are provided for use in dynamic environments to mitigate impact damage and increase wear resistance.

  9. Aligned composite structures for mitigation of impact damage and resistance to wear in dynamic environments

    DOEpatents

    Mulligan, Anthony C.; Rigali, Mark J.; Sutaria, Manish P.; Popovich, Dragan; Halloran, Joseph P.; Fulcher, Michael L.; Cook, Randy C.

    2009-04-14

    Fibrous monolith composites having architectures that provide increased flaw insensitivity, improved hardness, wear resistance and damage tolerance and methods of manufacture thereof are provided for use in dynamic environments to mitigate impact damage and increase wear resistance.

  10. Aligned composite structures for mitigation of impact damage and resistance to wear in dynamic environments

    DOEpatents

    Rigali, Mark J.; Sutaria, Manish P.; Mulligan, Anthony C.; Popovich, Dragan

    2004-03-23

    Fibrous monolith composites having architectures that provide increased flaw insensitivity, improved hardness, wear resistance and damage tolerance and methods of manufacture thereof are provided for use in dynamic environments to mitigate impact damage and increase wear resistance.

  11. An Assessment of Molecular Dynamic Force Fields for Silica for Use in Simulating Laser Damage Mitigation

    SciTech Connect

    Soules, T F; Gilmer, G H; Matthews, M J; Stolken, J S; Feit, M D

    2010-10-21

    We compare force fields (FF's) that have been used in molecular dynamic (MD) simulations of silica in order to assess their applicability for use in simulating IR-laser damage mitigation. Although pairwise FF?s obtained by fitting quantum mechanical calculations such as the BKS and CHIK potentials have been shown to reproduce many of the properties of silica including the stability of silica polymorphs and the densification of the liquid, we show that melting temperatures and fictive temperatures are much too high. Softer empirical force fields give liquid and glass properties at experimental temperatures but may not predict all properties important to laser mitigation experiments.

  12. Fabrication of mitigation pits for improving laser damage resistance in dielectric mirrors by femtosecond laser machining

    SciTech Connect

    Wolfe, Justin E.; Qiu, S. Roger; Stolz, Christopher J.

    2011-03-20

    Femtosecond laser machining is used to create mitigation pits to stabilize nanosecond laser-induced damage in multilayer dielectric mirror coatings on BK7 substrates. In this paper, we characterize features and the artifacts associated with mitigation pits and further investigate the impact of pulse energy and pulse duration on pit quality and damage resistance. Our results show that these mitigation features can double the fluence-handling capability of large-aperture optical multilayer mirror coatings and further demonstrate that femtosecond laser macromachining is a promising means for fabricating mitigation geometry in multilayer coatings to increase mirror performance under high-power laser irradiation.

  13. Kinetic Ductility and Force-Spike Resistance of Proteins from Single-Molecule Force Spectroscopy.

    PubMed

    Cossio, Pilar; Hummer, Gerhard; Szabo, Attila

    2016-08-23

    Ductile materials can absorb spikes in mechanical force, whereas brittle ones fail catastrophically. Here we develop a theory to quantify the kinetic ductility of single molecules from force spectroscopy experiments, relating force-spike resistance to the differential responses of the intact protein and the unfolding transition state to an applied mechanical force. We introduce a class of unistable one-dimensional potential surfaces that encompass previous models as special cases and continuously cover the entire range from ductile to brittle. Compact analytic expressions for force-dependent rates and rupture-force distributions allow us to analyze force-clamp and force-ramp pulling experiments. We find that the force-transmitting protein domains of filamin and titin are kinetically ductile when pulled from their two termini, making them resistant to force spikes. For the mechanostable muscle protein titin, a highly ductile model reconciles data over 10 orders of magnitude in force loading rate from experiment and simulation. PMID:27558726

  14. Sensitivity of Space Launch System Buffet Forcing Functions to Buffet Mitigation Options

    NASA Technical Reports Server (NTRS)

    Piatak, David J.; Sekula, Martin K.; Rausch, Russ D.

    2016-01-01

    Time-varying buffet forcing functions arise from unsteady aerodynamic pressures and are one of many load environments, which contribute to the overall loading condition of a launch vehicle during ascent through the atmosphere. The buffet environment is typically highest at transonic conditions and can excite the vehicle dynamic modes of vibration. The vehicle response to these buffet forcing functions may cause high structural bending moments and vibratory environments, which can exceed the capabilities of the structure, or of vehicle components such as payloads and avionics. Vehicle configurations, protuberances, payload fairings, and large changes in stage diameter can trigger undesirable buffet environments. The Space Launch System (SLS) multi-body configuration and its structural dynamic characteristics presented challenges to the load cycle design process with respect to buffet-induced loads and responses. An initial wind-tunnel test of a 3-percent scale SLS rigid buffet model was conducted in 2012 and revealed high buffet environments behind the booster forward attachment protuberance, which contributed to reduced vehicle structural margins. Six buffet mitigation options were explored to alleviate the high buffet environments including modified booster nose cones and fences/strakes on the booster and core. These studies led to a second buffet test program that was conducted in 2014 to assess the ability of the buffet mitigation options to reduce buffet environments on the vehicle. This paper will present comparisons of buffet forcing functions from each of the buffet mitigation options tested, with a focus on sectional forcing function rms levels within regions of the vehicle prone to high buffet environments.

  15. (-)-Epicatechin mitigates high fructose-associated insulin resistance by modulating redox signaling and endoplasmic reticulum stress

    PubMed Central

    Bettaieb, Ahmed; Vazquez Prieto, Marcela A.; Rodriguez Lanzi, Cecilia; Miatello, Roberto M.; Haj, Fawaz G.; Fraga, César G.; Oteiza, Patricia I.

    2014-01-01

    We investigated the capacity of dietary (-)-epicatechin (EC) to mitigate insulin resistance through the modulation of redox-regulated mechanisms in a rat model of metabolic syndrome (MetS). Adolescent rats were fed a regular chow diet without or with high fructose (HFr) (10% (w/v)) in drinking water for 8 weeks, and a group of HFr-fed rats was supplemented with EC in the diet. HFr-fed rats developed insulin resistance which was mitigated by EC supplementation. Accordingly, the activation of components of the insulin signaling cascade (insulin receptor (IR), IRS-1, Akt and ERK1/2) was impaired, while negative regulators (PKC, IKK, JNK and PTP1B) were upregulated in the liver and adipose tissue of HFr rats. These alterations were partially or totally prevented by EC supplementation. In addition, EC inhibited events which contribute to insulin resistance: HFr-associated increased expression and activity of NADPH oxidase, activation of redox-sensitive signals, expression of NF-κB-regulated pro-inflammatory cytokines and chemokines, and some sub-arms of endoplasmic reticulum stress signaling. Collectively, these findings indicate that EC supplementation can mitigate HFr-induced insulin resistance and are relevant to define interventions that can prevent/mitigate MetS-associated insulin resistance. PMID:24746618

  16. Searching for optimal mitigation geometries for laser resistant multilayer high reflector coatings

    SciTech Connect

    Qiu, S R; Wolfe, J E; Monterrosa, A M; Feit, M D; Pistor, T V; STolz, C J

    2011-02-11

    Growing laser damage sites on multilayer high reflector coatings can limit mirror performance. One of the strategies to improve laser damage resistance is to replace the growing damage sites with pre-designed benign mitigation structures. By mitigating the weakest site on the optic, the large aperture mirror will have a laser resistance comparable to the intrinsic value of the multilayer coating. To determine the optimal mitigation geometry, the finite difference time domain method (FDTD) was used to quantify the electric-field intensification within the multilayer, at the presence of different conical pits. We find that the field intensification induced by the mitigation pit is strongly dependent on the polarization and the angle of incidence (AOI) of the incoming wave. Therefore the optimal mitigation conical pit geometry is application specific. Furthermore, our simulation also illustrates an alternative means to achieve an optimal mitigation structure by matching the cone angle of the structure with the AOI of the incoming wave, except for the p-polarization wave at a range of incident angles between 30{sup o} and 45{sup o}.

  17. Comprehensive radiative forcing assesment highlights trade-offs in climate mitigation potential of managed boreal forests

    NASA Astrophysics Data System (ADS)

    Kalliokoski, Tuomo; Berninger, Frank; Bäck, Jaana; Boy, Michael; Kuusinen, Nea; Mäkelä, Annikki; Matthies, Brent; Minkkinen, Kari; Mogensen, Ditte; Peltoniemi, Mikko; Sievänen, Risto; Zhou, Luxi; Vanhatalo, Anni; Valsta, Lauri; Nikinmaa, Eero

    2016-04-01

    Boreal forests have an important role in the mitigation of climate change. In this study we evaluated four key climate impacts of forest management: (1) carbon sequestration (in forest ecosystems and wood products), (2) surface albedo of forest area, (3) forest originating Secondary Organic Aerosols (SOA) and (4) avoided CO2-emissions from wood energy and product substitution. We calculated their net effect at both a single stand and regional level using Finland as a case study. We made analyses both in current climate up to a year 2050 and in the projected climate of year 2050. At the stand level, the carbon sequestration effect and avoided CO2 emissions due to substituted materials dominated in net RF in current climate. The warming effect of surface albedo of forest cover was lower or of same magnitude than cooling effect of SOAs. Together, the rarely considered SOAs and product substitution corresponded over 70% of the total cooling effect of forest cover. The cooling effect of net radiative forcing increased along the increasing site fertility. Although the carbon stocks of broadleaved trees were smaller than that of conifers their total radiative cooling effect was larger due to the integrated albedo and aerosol effects. In the projected climate of 2050, the radiative cooling of aerosols approached the level of forest carbon fixation. These results emphasize the need for holistic evaluation of climate impacts over simple carbon sequestration analysis to understand the role of forest management in climate change mitigation. Landscape level analyses emphasized the broad range of options to reach the cooling effect. The lowest harvest regime, 50% of current annual increment (CAI), yielded the largest cooling effect. Yet, harvests up to CAI produced only slightly less cooling RF if avoided emissions were considered. This result was highly sensitive to used substitution factors. Our result highlights that the combination of intensive harvests and the use of wood

  18. Gravity-independent constant force resistive exercise unit

    NASA Technical Reports Server (NTRS)

    Colosky, Jr., Paul E. (Inventor); Ruttley, Tara M. (Inventor)

    2004-01-01

    This invention describes a novel gravity-independent exercise unit designed for use in microgravity, or on the ground, as a means by which to counter muscle atrophy and bone degradation due to disuse or underuse. Modular resistive packs comprising constant torque springs provide constant force opposing the withdrawal of an exercise cable from the device. In addition to uses within the space program, the compact resistive packs of the CFREU allow the unit to be small enough for easy use as a home gym for personal use, or as a supplement for rehabilitation programs. Resistive packs may be changed conveniently out of the CFREU according to the desired exercise regimen. Thus, the resistive packs replace the need for expensive, heavy, and bulky traditional weight plates. The CFREU may be employed by hospitals, rehabilitation and physical therapy clinics, and other related professional businesses.

  19. Correlation Between Two Types of Surface Stress Mitigation and the Resistance to Corrosion of Alloy 22

    SciTech Connect

    Yilmaz, A; Fix, D V; Estill, J C; Rebak, R B

    2005-02-04

    When metallic plates are welded, residual tensile stresses may develop in the vicinity of the weld seam. Processes such as Low Plasticity Burnishing (LPB) and Laser Shock Peening (LSP) could be applied locally to eliminate the residual stresses produced by welding. In this study, Alloy 22 (N06022) plates were welded and then the above-mentioned surface treatments were applied to eliminate the residual tensile stresses. The aim of the current study was to compare the corrosion behavior of as-welded (ASW) plates with the corrosion behavior of plates with stress mitigated surfaces. Immersion and electrochemical tests were performed. Results show that the corrosion resistance of the mitigated plates was not affected by the surface treatments applied.

  20. The effectiveness of resistive force theory in granular locomotiona)

    NASA Astrophysics Data System (ADS)

    Zhang, Tingnan; Goldman, Daniel I.

    2014-10-01

    Resistive force theory (RFT) is often used to analyze the movement of microscopic organisms swimming in fluids. In RFT, a body is partitioned into infinitesimal segments, each of which generates thrust and experiences drag. Linear superposition of forces from elements over the body allows prediction of swimming velocities and efficiencies. We show that RFT quantitatively describes the movement of animals and robots that move on and within dry granular media (GM), collections of particles that display solid, fluid, and gas-like features. RFT works well when the GM is slightly polydisperse, and in the "frictional fluid" regime such that frictional forces dominate material inertial forces, and when locomotion can be approximated as confined to a plane. Within a given plane (horizontal or vertical) relationships that govern the force versus orientation of an elemental intruder are functionally independent of the granular medium. We use the RFT to explain features of locomotion on and within granular media including kinematic and muscle activation patterns during sand-swimming by a sandfish lizard and a shovel-nosed snake, optimal movement patterns of a Purcell 3-link sand-swimming robot revealed by a geometric mechanics approach, and legged locomotion of small robots on the surface of GM. We close by discussing situations to which granular RFT has not yet been applied (such as inclined granular surfaces), and the advances in the physics of granular media needed to apply RFT in such situations.

  1. Challenges and mitigation strategies for resist trim etch in resist-mandrel based SAQP integration scheme

    NASA Astrophysics Data System (ADS)

    Mohanty, Nihar; Franke, Elliott; Liu, Eric; Raley, Angelique; Smith, Jeffrey; Farrell, Richard; Wang, Mingmei; Ito, Kiyohito; Das, Sanjana; Ko, Akiteru; Kumar, Kaushik; Ranjan, Alok; O'Meara, David; Nawa, Kenjiro; Scheer, Steven; DeVillers, Anton; Biolsi, Peter

    2015-03-01

    Patterning the desired narrow pitch at 10nm technology node and beyond, necessitates employment of either extreme ultra violet (EUV) lithography or multi-patterning solutions based on 193nm-immersion lithography. With enormous challenges being faced in getting EUV lithography ready for production, multi-patterning solutions that leverage the already installed base of 193nm-immersion-lithography are poised to become the industry norm for 10 and 7nm technology nodes. For patterning sub-40nm pitch line/space features, self-aligned quadruple patterning (SAQP) with resist pattern as the first mandrel shows significant cost as well as design benefit, as compared to EUV lithography or other multi-patterning techniques. One of the most critical steps in this patterning scheme is the resist mandrel definition step which involves trimming / reformation of resist profile via plasma etch for achieving appropriate pitch after the final pattern. Being the first mandrel, the requirements for the Line Edge Roughness (LER) / Line Width Roughness (LWR); critical dimension uniformity (CDU); and profile in 3-dimensions for the resist trim / reformation etch is extremely aggressive. In this paper we highlight the unique challenges associated in developing resist trim / reformation plasma etch process for SAQP integration scheme and summarize our efforts in optimizing the trim etch chemistries, process steps and plasma etch parameters for meeting the mandrel definition targets. Finally, we have shown successful patterning of 30nm pitch patterns via the resist-mandrel SAQP scheme and its implementation for Si-fin formation at 7nm node.

  2. Calcined Eggshell Waste for Mitigating Soil Antibiotic-Resistant Bacteria/Antibiotic Resistance Gene Dissemination and Accumulation in Bell Pepper.

    PubMed

    Ye, Mao; Sun, Mingming; Feng, Yanfang; Li, Xu; Schwab, Arthur P; Wan, Jinzhong; Liu, Manqiang; Tian, Da; Liu, Kuan; Wu, Jun; Jiang, Xin

    2016-07-13

    The combined accumulation of antibiotics, heavy metals, antibiotic-resistant bacteria (ARB)/antibiotic resistance genes (ARGs) in vegetables has become a new threat to human health. This is the first study to investigate the feasibility of calcined eggshells modified by aluminum sulfate as novel agricultural wastes to impede mixed contaminants from transferring to bell pepper (Capsicum annuum L.). In this work, calcined eggshell amendment mitigated mixed pollutant accumulation in bell pepper significantly, enhanced the dissipation of soil tetracycline, sulfadiazine, roxithromycin, and chloramphenicol, decreased the water-soluble fractions of antibiotics, and declined the diversity of ARB/ARGs inside the vegetable. Moreover, quantitative polymerase chain reaction analysis detected that ARG levels in the bell pepper fruits significantly decreased to 10(-10) copies/16S copies, indicating limited risk of ARGs transferring along the food chain. Furthermore, the restoration of soil microbial biological function suggests that calcined eggshell is an environmentally friendly amendment to control the dissemination of soil ARB/ARGs in the soil-vegetable system. PMID:27333280

  3. Early Detection and Mitigation of Resistance to Bt Maize by Western Corn Rootworm (Coleoptera: Chrysomelidae).

    PubMed

    Andow, David A; Pueppke, Steven G; Schaafsma, Arthur W; Gassmann, Aaron J; Sappington, Thomas W; Meinke, Lance J; Mitchell, Paul D; Hurley, Terrance M; Hellmich, Richard L; Porter, R Pat

    2016-02-01

    Transgenic Bt maize that produces less than a high-dose has been widely adopted and presents considerable insect resistance management (IRM) challenges. Western corn rootworm, Diabrotica virgifera virgifera LeConte, has rapidly evolved resistance to Bt maize in the field, leading to local loss of efficacy for some corn rootworm Bt maize events. Documenting and responding to this resistance has been complicated by a lack of rapid diagnostic bioassays and by regulatory triggers that hinder timely and effective management responses. These failures are of great concern to the scientific and agricultural community. Specific challenges posed by western corn rootworm resistance to Bt maize, and more general concerns around Bt crops that produce less than a high-dose of Bt toxin, have caused uncertainty around current IRM protocols. More than 15 years of experience with IRM has shown that high-dose and refuge-based IRM is not applicable to Bt crops that produce less than a high-dose. Adaptive IRM approaches and pro-active, integrated IRM-pest management strategies are needed and should be in place before release of new technologies that produce less than a high-dose. We suggest changes in IRM strategies to preserve the utility of corn rootworm Bt maize by 1) targeting local resistance management earlier in the sequence of responses to resistance and 2) developing area-wide criteria to address widespread economic losses. We also favor consideration of policies and programs to counteract economic forces that are contributing to rapid resistance evolution. PMID:26362989

  4. Probing biofouling resistant polymer brush surfaces by atomic force microscopy based force spectroscopy.

    PubMed

    Schön, Peter; Kutnyanszky, Edit; ten Donkelaar, Bas; Santonicola, M Gabriella; Tecim, Tugba; Aldred, Nick; Clare, Anthony S; Vancso, G Julius

    2013-02-01

    The protein repellency and biofouling resistance of zwitterionic poly(sulfobetaine methacrylate)(pSBMA) brushes grafted via surface initiated polymerization (SIP) from silicon and glass substrata was assessed using atomic force microscopy (AFM) adherence experiments. Laboratory settlement assays were conducted with cypris larvae of the barnacle Balanus amphitrite. AFM adherence includes the determination of contact rupture forces when AFM probe tips are withdrawn from the substratum. When the surface of the AFM tip is modified, adherence can be assessed with chemical specifity using a method known as chemical force microscopy (CFM). In this study, AFM tips were chemically functionalized with (a) fibronectin- here used as model for a nonspecifically adhering protein - and (b) arginine-glycine-aspartic acid (RGD) peptide motifs covalently attached to poly(methacrylic acid) (PMAA) brushes as biomimics of cellular adhesion receptors. Fibronectin functionalized tips showed significantly reduced nonspecific adhesion to pSBMA-modified substrata compared to bare gold (2.3±0.75 nN) and octadecanethiol (ODT) self-assembled monolayers (1.3±0.75 nN). PMAA and PMAA-RGD modified probes showed no significant adhesion to pSBMA modified silicon substrata. The results gathered through AFM protein adherence studies were complemented by laboratory fouling studies, which showed no adhesion of cypris larvae of Balanus amphitrite on pSBMA. With regard to its unusually high non-specific adsorption to a wide variety of materials the behavior of fibronectin is analogous to the barnacle cyprid temporary adhesive that also binds well to surfaces differing in polarity, charge and free energy. The antifouling efficacy of pSBMA may, therefore, be directly related to the ability of this surface to resist nonspecific protein adsorption. PMID:23138001

  5. Defense Waste Processing Facility: Report of task force on options to mitigate the effect of nitrite on DWPF operations

    SciTech Connect

    Randall, D.; Marek, J.C.

    1992-03-01

    The possibility of accumulating ammonium nitrate (an explosive) as well as organic compounds in the DWPF Chemical Processing Cell Vent System was recently discovered. A task force was therefore organized to examine ways to avoid this potential hazard. Of thirty-two processing/engineering options screened, the task force recommended five options, deemed to have the highest technical certainty, for detailed development and evaluation: Radiolysis of nitrite in the tetraphenylborate precipitate slurry feed in a new corrosion-resistant facility. Construction of a Late Washing Facility for precipitate washing before transfer to the DWPF; Just-in-Time'' precipitation; Startup Workaround by radiolysis of nitrite in the existing corrosion-resistant Pump Pit tanks; Ammonia venting and organics separation in the DWPF; and, Estimated costs and schedules are included in this report.

  6. To mitigate, resist, or undo: addressing structural influences on the health of urban populations.

    PubMed Central

    Geronimus, A T

    2000-01-01

    Young to middle-aged residents of impoverished urban areas suffer extra-ordinary rates of excess mortality, to which deaths from chronic disease contribute heavily. Understanding of urban health disadvantages and attempts to reverse them will be incomplete if the structural factors that produced modern minority ghettos in central cities are not taken into account. Dynamic conceptions of the role of race/ethnicity in producing health inequalities must encompass (1) social relationship between majority and minority populations that privilege the majority population and (2) the autonomous institutions within minority populations that members develop and sustain to mitigate, resist, or undo the adverse effects of discrimination. Broad social and economic policies that intensify poverty or undermine autonomous protections can reap dire consequences for health. Following from this structural analysis and previous research, guiding principles for action and suggestions for continued research are proposed. Without taking poverty and race/ethnicity into account, public health professionals who hope to redress the health problems of urban life risk exaggerating the returns that can be expected of public health campaigns or overlooking important approaches for mounting successful interventions. PMID:10846503

  7. Transient Dynamics of Elastic Hele-Shaw Cell due to External Forces with Application to Impact Mitigation

    NASA Astrophysics Data System (ADS)

    Tulchinsky, Arie; Gat, Amir

    2015-11-01

    We study the transient dynamics of a viscous liquid contained in a narrow gap between a rigid plate and an elastic plate. The elastic plate is under the influence of an externally applied time varying force acting perpendicular to its surface. We model the flow in the narrow gap via the lubrication approximation, and the plate by the Kirchhoff-Love plate theory. The viscous-elastic interaction yields a governing 6th-order linear partial differential equation. We obtain a semi-similarity solution for the case of an external point force acting on the elastic plate. The pressure and deformation field during and after the application of the external force are derived and presented by closed form expressions. We examine a uniform external pressure acting on the elastic plate over a finite region and during a finite time period similar to the viscous-elastic interaction time-scale. The interaction between elasticity and viscosity is shown to reduce by order of magnitude the pressure within the Hele-Shaw cell compared with the externally applied pressure, thus suggesting such configurations may be used for impact mitigation.

  8. DESIGN OF NEW SCHOOLS AND OTHER LARGE BUILDINGS WHICH ARE RADON RESISTANT AND EASY TO MITIGATE

    EPA Science Inventory

    The paper discusses the recent incorporation of radon mitigation design recommendations in the construction of a hospital in Johnson City, TN. he recommendations resulted in the mitigation of a 5,500 square meter building with only one suction point at an incremental cost of $1.0...

  9. Fluctuating Pressure Environments and Hydrodynamic Radial Force Mitigation for a Two Blade Unshrouded Inducer

    NASA Technical Reports Server (NTRS)

    Mulder, Andrew; Skelley, Stephen

    2011-01-01

    Fluctuating pressure data from water flow testing of an unshrouded two blade inducer revealed a cavitation induced oscillation with the potential to induce a radial load on the turbopump shaft in addition to other more traditionally analyzed radial loads. Subsequent water flow testing of the inducer with a rotating force measurement system confirmed that the cavitation induced oscillation did impart a radial load to the inducer. After quantifying the load in a baseline configuration, two inducer shroud treatments were selected and tested to reduce the cavitation induced load. The first treatment was to increase the tip clearance, and the second was to introduce a circumferential groove near the inducer leading edge. Increasing the clearance resulted in a small decrease in radial load along with some steady performance degradation. The groove greatly reduced the hydrodynamic load with little to no steady performance loss. The groove did however generate some new, relatively high frequency, spatially complex oscillations to the flow environment.

  10. Assessment of Structural Resistance of building 4862 to Earthquake and Tornado Forces [SEC 1 and 2

    SciTech Connect

    METCALF, I.L.

    1999-12-06

    This report presents the results of work done for Hanford Engineering Laboratory under contract Y213-544-12662. LATA performed an assessment of building 4862 resistance to earthquake and tornado forces.

  11. Study on effect of electrode force on resistance spot welding process

    NASA Astrophysics Data System (ADS)

    Zhou, Kang; Cai, Lilong

    2014-08-01

    This paper deals with the effect of electrode force on resistance spot welding process. As one of the most important parameters during the process, the electrode force can influence the process in different aspects. Dynamic resistance, which can reflect the internal physical variation of the workpiece, is employed to monitor the characteristic variation of the workpieces. According to theoretical analysis, large electrode force may easily induce surface expulsion. Also, it can decrease the overall dynamic resistance values and postpone the time when first melting point appears, as well as enlarge the duration between times when first melting point and peak value appear. Larger electrode force induces the initial smaller nugget diameter, and then the nugget diameter has a higher growth speed. However, the overall nugget diameter may be smaller and its growth terminates earlier than when smaller electrode force is applied. Final experiments validated all the theoretical analysis.

  12. Does cryptic microbiota mitigate pine resistance to an invasive beetle-fungus complex? Implications for invasion potential.

    PubMed

    Cheng, Chihang; Xu, Letian; Xu, Dandan; Lou, Qiaozhe; Lu, Min; Sun, Jianghua

    2016-01-01

    Microbial symbionts are known to assist exotic pests in their colonization of new host plants. However, there has been little evidence linking symbiotic invasion success to mechanisms for mitigation of native plant resistance. The red turpentine beetle (RTB) was introduced with a fungus, Leptographium procerum, to China from the United States and became a destructively invasive symbiotic complex in natural Pinus tabuliformis forests. Here, we report that three Chinese-resident fungi, newly acquired by RTB in China, induce high levels of a phenolic defensive chemical, naringenin, in pines. This invasive beetle-fungus complex is suppressed by elevated levels of naringenin. However, cryptic microbiotas in RTB galleries strongly degrade naringenin, and pinitol, the main soluble carbohydrate of P. tabuliformis, is retained in L. procerum-infected phloem and facilitate naringenin biodegradation by the microbiotas. These results demonstrate that cryptic microbiota mitigates native host plant phenolic resistance to an invasive symbiotic complex, suggesting a putative mechanism for reduced biotic resistance to symbiotic invasion. PMID:27621032

  13. Viscous forces are predominant in the zona pellucida mechanical resistance

    NASA Astrophysics Data System (ADS)

    Papi, Massimiliano; Maiorana, Alessandro; Douet, Cécile; Maulucci, Giuseppe; Parasassi, Tiziana; Brunelli, Roberto; Goudet, Ghylène; De Spirito, Marco

    2013-01-01

    The zona pellucida (ZP) is a multilayer glycoprotein spherical shell surrounding mammalian eggs. The ZP's mechanical response plays a crucial role in mammalian fertilization and is a parameter commonly adopted in "in vitro fertilization" to characterize the oocytes quality. While it is assumed that ZP mechanical response is purely elastic, here we prove that dissipative forces cannot be neglected. Physiologically, this evidence implies that an increase in the spermatozoa motility can induce dramatic changes on the ZP reaction force turning ZP shell in an impenetrable barrier leading to fertility impairments.

  14. The subsurface cross section resistivity using magnetotelluric method in Pelabuhan Ratu area, West Java, implication for geological hazard mitigation

    NASA Astrophysics Data System (ADS)

    Gaffar, Eddy Z.

    2016-02-01

    Pelabuhan Ratu area is located on the south coast of West Java. Pelabuhan Ratu area's rapid development and population growth were partly stimulated by the Indonesian Government Regulation No. 66 the year 1998 that made Pelabuhan Ratu the capital city of the district of Sukabumi. Because of this fact, it is very important to create a geological hazard mitigation plan for the area. Pelabuhan Ratu were passed by two major faults: Cimandiri fault in the western and Citarik fault in the eastern. Cimandiri fault starts from the upstream of Cimandiri River to the southern of Sukabumi and Cianjur city. While Citarik fault starts from the Citarik River until the Salak Mountain. These two faults needs to be observed closely as they are prone to cause earthquake in the area. To mitigate earthquake that is estimated will occur at Cimandiri fault or the Citarik fault, the Research Center for Geotechnology LIPI conducted research using Magnetotelluric (MT) method with artificial Phoenix MT tool to determine the cross-section resistivity of the Pelabuhan Ratu and the surrounding area. Measurements were taken at 40 points along the highway towards Jampang to Pelabuhan Ratu, and to Bandung towards Cibadak with a distance of less than 500 meters between the measuring points. Measurement results using this tool will generate AMT cross-section resistivity to a depth of 1500 meters below the surface. Cross-section resistivity measurement results showed that there was a layer of rock with about 10 Ohm-m to 1000 Ohm-m resistivity. Rocks with resistivity of 10 Ohm-m was interpreted as conductive rocks that were loose or sandstone containing water. If an earthquake to occur in this area, it will lead to a strong movement and liquefaction that will destroy buildings and potentially cause casualties in this area.

  15. Professional Value Conflicts in Forcing Services on Resistant Older Clients.

    ERIC Educational Resources Information Center

    Hayes, Christopher L.

    Clinicians who work with at-risk older adults are often faced with the difficult decision to override their client's civil rights and force institutionalization. Many times the professional is pressured by police or a housing manager to "just do something" with the judgmentally impaired older client. Clinicians faced with these decisions may…

  16. Indirect costs of a nontarget pathogen mitigate the direct benefits of a virus-resistant transgene in wild Cucurbita

    PubMed Central

    Sasu, Miruna A.; Ferrari, Matthew J.; Du, Daolin; Winsor, James A.; Stephenson, Andrew G.

    2009-01-01

    Virus-resistant transgenic squash are grown throughout the United States and much of Mexico and it is likely that the virus-resistant transgene (VRT) has been introduced to wild populations repeatedly. The evolutionary fate of any resistance gene in wild populations and its environmental impacts depend upon trade-offs between the costs and benefits of the resistance gene. In a 3-year field study using a wild gourd and transgenic and nontransgenic introgressives, we measured the effects of the transgene on fitness, on herbivory by cucumber beetles, on the incidence of mosaic viruses, and on the incidence of bacterial wilt disease (a fatal disease vectored by cucumber beetles). In each year, the first incidence of zucchini yellow mosaic virus occurred in mid-July and spread rapidly through the susceptible plants. We found that the transgenic plants had greater reproduction through both male and female function than the susceptible plants, indicating that the VRT has a direct fitness benefit for wild gourds under the conditions of our study. Moreover, the VRT had no effect on resistance to cucumber beetles or the incidence of wilt disease before the spread of the virus. However, as the virus spread through the fields, the cucumber beetles became increasingly concentrated upon the healthy (mostly transgenic) plants, which increased exposure to and the incidence of wilt disease on the transgenic plants. This indirect cost of the VRT (mediated by a nontarget herbivore and pathogen) mitigated the overall beneficial effect of the VRT on fitness. PMID:19858473

  17. Mitigation of peroxynitrite-mediated nitric oxide (NO) toxicity as a mechanism of induced adaptive NO resistance in the CNS.

    PubMed

    Bishop, Amy; Gooch, Renea; Eguchi, Asuka; Jeffrey, Stephanie; Smallwood, Lorraine; Anderson, James; Estevez, Alvaro G

    2009-04-01

    During CNS injury and diseases, nitric oxide (NO) is released at a high flux rate leading to formation of peroxynitrite (ONOO(*)) and other reactive nitrogenous species, which nitrate tyrosines of proteins to form 3-nitrotyrosine (3NY), leading to cell death. Previously, we have found that motor neurons exposed to low levels of NO become resistant to subsequent cytotoxic NO challenge; an effect dubbed induced adaptive resistance (IAR). Here, we report IAR mitigates, not only cell death, but 3NY formation in response to cytotoxic NO. Addition of an NO scavenger before NO challenge duplicates IAR, implicating reactive nitrogenous species in cell death. Addition of uric acid (a peroxynitrite scavenger) before cytotoxic NO challenge, duplicates IAR, implicating peroxynitrite, with subsequent 3NY formation, in cell death, and abrogation of this pathway as a mechanism of IAR. IAR is dependent on the heme-metabolizing enzyme, heme oxygenase-1 (HO1), as indicated by the elimination of IAR by a specific HO1 inhibitor, and by the finding that neurons isolated from HO1 null mice have increased NO sensitivity with concomitant increased 3NY formation. This data indicate that IAR is an HO1-dependent mechanism that prevents peroxynitrite-mediated NO toxicity in motor neurons, thereby elucidating therapeutic targets for the mitigation of CNS disease and injury. PMID:19183270

  18. WIse-2005: Combined Aerobic and Resistive Exercise May Help Mitigate Bone Loss During 60-D Simulated Microgravity in Women

    NASA Technical Reports Server (NTRS)

    Smith, Scott M.; Zwart, S. R.; Heer, M. A.; Lee, S. M. C.; Macias, B. R.; Schneider, S. M.; Trappe, S. M.; Hargens, A. R.

    2006-01-01

    Exercise can attenuate bone loss associated with disuse during bed rest (BR), an analog of space flight. Previous studies have examined the efficacy of aerobic or resistive exercise countermeasures, but not in combination. We sought to determine the effect of a combined resistive and aerobic exercise regimen on bone metabolism during BR. After a 20-d ambulatory adaptation to confinement and diet, 16 women participated in a 60-d head-down-tilt BR. Control subjects (CN, n=8) performed no countermeasures. Exercise subjects, (EX, n=8) participated in exercise alternating daily between supine treadmill exercise within lower body negative pressure and resistive fly-wheel exercise (6-d wk(sup -1)). In the last week of BR, bone resorption was greater (p less than 79 plus or minus 44%, mean plus or minus SD) and EX groups (64 50%). N-telopeptide also increased (CN: 51 plus or minus 34%; EX: 43 plus or minus 56%). However, bone-specific alkaline phosphatase, a bone formation marker, tended to be higher in EX (26 plus or minus 18%) than in CN (8 plus or minus 33%) groups. The combination of resistive and aerobic exercise does not prevent bone resorption, but may promote formation, potentially mitigating the net bone loss associated with simulated microgravity. This study was supported by CNES, CSA, ESA, NASA, and NASA grant NNJ04HF71G to ARH. MEDES (French Institute for Space Medicine and Physiology) organized the study.

  19. Acute effect of front crawl sprint resisted swimming on the propulsive forces of the hand.

    PubMed

    Gourgoulis, Vassilios; Aggeloussis, Nikolaos; Mavridis, Georgios; Boli, Alexia; Kasimatis, Panagiotis; Vezos, Nikolaos; Toubekis, Argyris; Antoniou, Panagiotis; Mavrommatis, Georgios

    2013-02-01

    The purpose of the current study was to investigate the acute effect of sprint resisted front crawl swimming on the propulsive forces of the hand. Eight female swimmers swam 25 m with maximal intensity, with and without added resistance. A bowl with a capacity of 2.2, 4 and 6 L was used as low, moderate and high added resistance, respectively. The underwater motion of the swimmer's right hand was recorded using 4 cameras (60 Hz) and the digitization was undertaken using the Ariel Performance Analysis System. Repeated-measures ANOVA revealed that the velocity of the hand, the pitch and the sweepback angles of the hand, as well as the magnitude and the relative contribution of the drag and lift forces were not significantly modified and thus the magnitude of the resultant force did not change. Moreover, the magnitude of the effective force, as well as the angle formed between the resultant force and the axis of the swimming propulsion were not significantly affected. Thus, it could be concluded that resistance added as in this study did not alter the pattern of the propulsive hand forces associated with front crawl sprinting. PMID:22813753

  20. Effect of velocity and added resistance on selected coordination and force parameters in front crawl.

    PubMed

    Schnitzler, Christophe; Brazier, Tim; Button, Chris; Seifert, Ludovic; Chollet, Didier

    2011-10-01

    The effect of (a) increasing velocity and (b) added resistance was examined on the stroke (stroke length, stroke rate [SR]), coordination (index of coordination [IdC], propulsive phases), and force (impulse and peaks) parameters of 7 national-level front crawl swimmers (17.14 ± 2.73 years of swimming; 57.67 ± 1.62 seconds in the 100-m freestyle). The additional resistance was provided by a specially designed parachute. Parachute swimming (PA) and free-swimming (F) conditions were compared at 5 velocities per condition. Video footage was used to calculate the stroke and coordination parameters, and sensors allowed the determination of force parameters. The results showed that (a) an increase in velocity (V) led to increases in SR, IdC, propulsive phase duration, and peak propulsive force (p < 0.05), but no significant change in force impulse per cycle, whatever the condition (PA or F); and (b) in PA conditions, significant increases in the IdC, propulsive phase duration, and force impulse and a decrease in SR were recorded at high velocities (p < 0.05). These results indicated that, in the F condition, swimmers adapted to the change in velocity by modifying stroke and coordination rather than force parameters, whereas the PA condition enhanced the continuity of propulsive action and force development. Added resistance, that is, "parachute training," can be used for specific strength training purposes as long as swimming is performed near maximum velocity. PMID:21912344

  1. A strategy to provide long-term control of weedy rice while mitigating herbicide resistance transgene flow, and its potential use for other crops with related weeds.

    PubMed

    Gressel, Jonathan; Valverde, Bernal E

    2009-07-01

    Transgenic herbicide-resistant rice is needed to control weeds that have evolved herbicide resistance, as well as for the weedy (feral, red) rice problem, which has been exacerbated by shifting to direct seeding throughout the world-firstly in Europe and the Americas, and now in Asia, as well as in parts of Africa. Transplanting had been the major method of weedy rice control. Experience with imidazolinone-resistant rice shows that gene flow to weedy rice is rapid, negating the utility of the technology. Transgenic technologies are available that can contain herbicide resistance within the crop (cleistogamy, male sterility, targeting to chloroplast genome, etc.), but such technologies are leaky. Mitigation technologies tandemly couple (genetically link) the gene of choice (herbicide resistance) with mitigation genes that are neutral or good for the crop, but render hybrids with weedy rice and their offspring unfit to compete. Mitigation genes confer traits such as non-shattering, dwarfism, no secondary dormancy and herbicide sensitivity. It is proposed to use glyphosate and glufosinate resistances separately as genes of choice, and glufosinate, glyphosate and bentazone susceptibilities as mitigating genes, with a six-season rotation where each stage kills transgenic crop volunteers and transgenic crop x weed hybrids from the previous season. PMID:19367567

  2. Flagellar hydrodynamics. A comparison between resistive-force theory and slender-body theory.

    PubMed Central

    Johnson, R E; Brokaw, C J

    1979-01-01

    This paper investigates the accuracy of the resistive-force theory (Gray and Hancock method) which is commonly used for hydrodynamic analysis of swimming flagella. We made a comparison between the forces, bending moments, and shear moments calculated by resistive-force theory and by the more accurate slender-body theory for large-amplitude, planar wave forms computed for a flagellar model. By making an upward empirical adjustment, by about 35%, of the classical drag coefficient values used in the resistive-force theory calculations, we obtained good agreement between the distributions of the forces and moments along the length of the flagellum predicted by the two methods when the flagellum has no cell body attached. After this adjustment, we found the rate of energy expenditure calculated by the two methods for the few typical test cases to be almost identical. The resistive-force theory is thus completely satisfactory for use in analysis of mechanisms for the control of flagellar bending, at the current level of sophistication of this analysis. We also examined the effects of the presence of a cell body attached to one end of the flagellum, which modifies the flow field experienced by the flagellum. This interaction, which is not considered in resistive-force theory, is probably insignificant for small cell bodies, such as the heads of simple spermatozoa, but for larger cell bodies, or cell bodies that have large-amplitude motions transverse to the swimming direction, use of slender-body theory is required for accurate analysis. PMID:262381

  3. Thermo-Electromotive Force and Electrical Resistivity of Hydrogenated VT1-0 Titanium Alloy

    NASA Astrophysics Data System (ADS)

    Lider, A.; Larionov, V.; Kroening, M.; Kudiiarov, V.

    2016-06-01

    The method for measuring the structure transition of hydrogenated titanium from one state to another is suggested. The method is based on the comparison of thermo-electromotive force (thermo-emf), DC electrical resistance and the results of X-ray diffraction analysis. X-ray diffraction analysis is applied for identifying the quantity of defects in titanium structure. The authors have also identified the identical dependence of thermo-electromotive force and electrical resistivity on hydrogen concentration in titanium. The effect can be used for hydrogenated titanium structure control.

  4. Multidrug-resistant organisms in liver transplant: Mitigating risk and managing infections.

    PubMed

    Hand, Jonathan; Patel, Gopi

    2016-08-01

    Liver transplant (LT) recipients are vulnerable to infections with multidrug-resistant (MDR) pathogens. Risk factors for colonization and infection with resistant bacteria are ubiquitous and unavoidable in transplantation. During the past decade, progress in transplantation and infection prevention has contributed to the decreased incidence of infections with methicillin-resistant Staphylococcus aureus. However, even in the face of potentially effective antibiotics, vancomycin-resistant enterococci continue to plague LT. Gram-negative bacilli prove to be more problematic and are responsible for high rates of both morbidity and mortality. Despite the licensure of novel antibiotics, there is no universal agent available to safely and effectively treat infections with MDR gram-negative organisms. Currently, efforts dedicated toward prevention and treatment require involvement of multiple disciplines including transplant providers, specialists in infectious diseases and infection prevention, and researchers dedicated to the development of rapid diagnostics and safe and effective antibiotics with novel mechanisms of action. Liver Transplantation 22 1143-1153 2016 AASLD. PMID:27228555

  5. Current resistance sources and breeding strategies to mitigate Ug99 threat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Continued spread of race Ug99 (TTKSK) of Puccinia graminis from Eastern Africa to Yemen and Iran, and its evolution to overcome resistance genes Sr24 and Sr36 has further increased the genetic vulnerability of wheat crop in Africa, Middle East and Asia where about 90% of the area is sown to moderate...

  6. Foot-Ground Reaction Force During Resistance Exercise in Parabolic Flight

    NASA Technical Reports Server (NTRS)

    Lee, Stuart M. C.; Cobb, Kendall; Loehr, James A.; Nguyen, Daniel; Schneider, Suzanne M.

    2003-01-01

    An interim Resistance Exercise Device (iRED) was designed to provide resistive exercise as a countermeasure to space flight-induced loss of muscle strength and endurance as well as decreased bone mineral density. The purpose of this project was to compare foot-ground reaction force during iRED exercise in normal gravity (l-g) versus micro gravity (O-g) achieved during parabolic flight. METHODS: Four subjects performed three exercises using the iRED (squat, heel raise, and deadlift) during I-g and O-g at a moderate intensity (60% of maximum strength during deadlift exercise). Foot-ground reaction force was measured in three axes (x,y,z) using a force plate, and the magnitude of the resultant force vector was calculated (r = X 2 + y2 + Z2 ). Range of motion (ROM) was measured using a linear encoder. Peak force (PkF) and total work (TW) were calculated using a customized computer program. Paired t-tests were used to test if significant differences (p.::::0.05) were observed between I-g and O-g exercise. RESULTS: PkF and TW measured in the resultant axis were significantly less in O-g for each of the exercises tested. During O-g, PkF was 42-46% and TW was 33- 37% of that measured during I-g. ROM and average time to complete each repetition were not different from I-g to O-g. CONCLUSIONS: When performing exercises in which body mass is a portion of the resistance during I-g, PkF and TW measured during resistive exercise were reduced approximately 60-70% during O-g. Thus, a resistive exercise device during O-g will be required to provided higher resistances to induce a similar training stimulus to that on Earth.

  7. Jammed granular cones affect frictional resistive forces at the onset of intrusion

    NASA Astrophysics Data System (ADS)

    Aguilar, Jeffrey; Goldman, Daniel

    Characterizing the functional form of granular resistive forces has allowed for analysis of the locomotion of animals and robots on and within dry granular media. Resistive force theory (RFT) has been an effective tool in predicting these forces for various locomotive gaits within the ``frictional fluid'' regime, where intrusions are sufficiently slow such that granular inertial effects are negligible. These forces have been typically described by a linear dependence to submersion depth. However, recent experiments on robotic jumping [Aguilar & Goldman, Nature Physics, 2015] have revealed the importance of considering the nonlinear effects at the onset of intrusion to accurately predict robot kinematics. Particle image velocimetry (PIV) analysis of sidewall grain flow during foot intrusion reveals a jammed granular cone that develops beneath the foot at the onset of intrusion. A geometric model of cone development combined with empirical RFT forces on angled conical surfaces was able to predict the non-linear force trajectory vs. depth for experimental intrusions of various foot sizes, suggesting that intruders experience non-linear frictional forces according to the shape of the granular jamming fronts that form at the onset of movement. This work was supported by NSF Physics of Living Systems, Burroughs Wellcome Fund, and the Army Research Office.

  8. Multimode resistive switching in nanoscale hafnium oxide stack as studied by atomic force microscopy

    NASA Astrophysics Data System (ADS)

    Hou, Y.; Celano, U.; Goux, L.; Liu, L.; Degraeve, R.; Cheng, Y.; Kang, J.; Jurczak, M.; Vandervorst, W.

    2016-07-01

    The nanoscale resistive switching in hafnium oxide stack is investigated by the conductive atomic force microscopy (C-AFM). The initial oxide stack is insulating and electrical stress from the C-AFM tip induces nanometric conductive filaments. Multimode resistive switching can be observed in consecutive operation cycles at one spot. The different modes are interpreted in the framework of a low defect quantum point contact theory. The model implies that the optimization of the conductive filament active region is crucial for the future application of nanoscale resistive switching devices.

  9. Silicone oil contamination and electrical contact resistance degradation of low-force gold contacts.

    SciTech Connect

    Dugger, Michael Thomas; Dickrell, Daniel John, III

    2006-02-01

    Hot-switched low-force gold electrical contact testing was performed using a nanomechanical test apparatus to ascertain the sensitivity of simulated microelectromechanical systems (MEMS) contact to silicone oil contamination. The observed cyclic contact resistance degradation was dependent on both closure rate and noncontact applied voltage. The decomposition of silicone oil from electrical arcing was hypothesized as the degradation mechanism.

  10. RESISTANCE TO ALVEOLAR SHAPE CHANGE LIMITS RANGE OF FORCE PROPAGATION IN LUNG PARENCHYMA

    PubMed Central

    Ma, Baoshun; Smith, Bradford J.; Bates, Jason H.T.

    2015-01-01

    We have recently shown that if the lung parenchyma is modeled in 2 dimensions as a network of springs arranged in a pattern of repeating hexagonal cells, the distortional forces around a contracting airway propagate much further from the airway wall than classic continuum theory predicts. In the present study we tested the hypothesis that this occurs because of the negligible shear modulus of a hexagonal spring network. We simulated the narrowing of an airway embedded in a hexagonal network of elastic alveolar walls when the hexagonal cells of the network offered some resistance to a change in shape. We found that as the forces resisting shape change approach about 10% of the forces resisting length change of an individual spring the range of distortional force propagation in the spring network fell of rapidly as in an elastic continuum. We repeated these investigations in a 3-dimensional spring network composed of space-filling polyhedral cells and found similar results. This suggests that force propagation away from a point of local parenchymal distortion also falls off rapidly in real lung tissue. PMID:25812796

  11. Structural defect-dependent resistive switching in Cu-O/Si studied by Kelvin probe force microscopy and conductive atomic force microscopy.

    PubMed

    Kumar, Mohit; Som, Tapobrata

    2015-08-28

    In this study, we show structural defect-dependent presence or absence of resistive switching in Cu-O films. We use Kelvin probe force microscopy and conductive atomic force microscopy to show the presence of resistive switching. In addition, local current mapping provides direct evidence on the formation of nanoscale filament. These findings match well with the existing theoretical model on resistive switching. In particular, understanding the role of structural defects in resistive switching can be considered as critically important to take a step forward for designing advanced nanoscale memory devices. PMID:26243354

  12. Bone loss during partial weight bearing (1/6th gravity) is mitigated by resistance and aerobic exercise in mice

    NASA Astrophysics Data System (ADS)

    Boudreaux, R. D.; Metzger, C. E.; Macias, B. R.; Shirazi-Fard, Y.; Hogan, H. A.; Bloomfield, S. A.

    2014-06-01

    Astronauts on long duration missions continue to experience bone loss, as much as 1-2% each month, for up to 4.5 years after a mission. Mechanical loading of bone with exercise has been shown to increase bone formation, mass, and geometry. The aim of this study was to compare the efficacy of two exercise protocols during a period of reduced gravitational loading (1/6th body weight) in mice. Since muscle contractions via resistance exercise impart the largest physiological loads on the skeleton, we hypothesized that resistance training (via vertical tower climbing) would better protect against the deleterious musculoskeletal effects of reduced gravitational weight bearing when compared to endurance exercise (treadmill running). Young adult female BALB/cBYJ mice were randomly assigned to three groups: 1/6 g (G/6; n=6), 1/6 g with treadmill running (G/6+RUN; n=8), or 1/6 g with vertical tower climbing (G/6+CLB; n=9). Exercise was performed five times per week. Reduced weight bearing for 21 days was achieved through a novel harness suspension system. Treadmill velocity (12-20 m/min) and daily run time duration (32-51 min) increased incrementally throughout the study. Bone geometry and volumetric bone mineral density (vBMD) at proximal metaphysis and mid-diaphysis tibia were assessed by in vivo peripheral quantitative computed tomography (pQCT) on days 0 and 21 and standard dynamic histomorphometry was performed on undemineralized sections of the mid-diaphysis after tissue harvest. G/6 caused a significant decrease (P<0.001) in proximal tibia metaphysis total vBMD (-9.6%). These reductions of tibia metaphyseal vBMD in G/6 mice were mitigated in both G/6+RUN and G/6+CLB groups (P<0.05). After 21 days of G/6, we saw an absolute increase in tibia mid-diaphysis vBMD and in distal metaphysis femur vBMD in both G/6+RUN and G/6+CLB mice (P<0.05). Substantial increases in endocortical and periosteal mineralizing surface (MS/BS) at mid-diaphysis tibia in G/6+CLB demonstrate that

  13. Foot-ground reaction force during resistive exercise in parabolic flight

    NASA Technical Reports Server (NTRS)

    Lee, Stuart M C.; Cobb, Kendall; Loehr, James A.; Nguyen, Daniel; Schneider, Suzanne M.

    2004-01-01

    INTRODUCTION: An interim resistance exercise device (iRED) was designed to provide resistive exercise as a countermeasure to spaceflight-induced loss of muscle strength and endurance as well as decreased bone mineral density. The purpose of this project was to compare foot-ground reaction force during iRED exercise in normal gravity (1 G) vs. microgravity (0 G) achieved during parabolic flight. METHODS: There were four subjects who performed three exercises (squat, heel raise, and deadlift) using the iRED during 1 G and 0 G at a moderate intensity (60% of maximum strength during deadlift exercise). Foot-ground reaction force was measured in the three orthogonal axes (x, y, z) using a force plate, and the magnitude of the resultant force vector was calculated (r = square root(x2 + y2 + z2)). Linear displacement (LD) was measured using a linear transducer. Peak force (Fpeak) and an index of total work (TWi) were calculated using a customized computer program. Paired t-tests were used to test if significant differences (p < or = 0.05) were observed between 1 G and 0 G exercise. RESULTS: Fpeak and TWi measured in the resultant axis were significantly less in 0 G for each of the exercises tested. During 0 G, Fpeak was 42-46% and TWi was 33-37% of that measured during 1 G. LD and average time to complete each repetition were not different from 1 G to 0 G. CONCLUSIONS: Crewmembers who perform resistive exercises during spaceflight that include the movement of a large portion of their body mass will require much greater external resistive force during 0 G than 1 G exercise to provide a sufficient stimulus to maintain muscle and bone mass.

  14. Force.

    ERIC Educational Resources Information Center

    Gamble, Reed

    1989-01-01

    Discusses pupil misconceptions concerning forces. Summarizes some of Assessment of Performance Unit's findings on meaning of (1) force, (2) force and motion in one dimension and two dimensions, and (3) Newton's second law. (YP)

  15. Distribution of resistive body-force in curved free-surface flow

    NASA Technical Reports Server (NTRS)

    Sivakumaran, N. S.; Dressler, R. F.

    1986-01-01

    The customary procedure for including resistive effects in turbulent hydraulic and stratified atmospheric flows is to integrate the empirically-known boundary shears over the entire wetted boundary of a thin fluid slab. A resistive body-force is then assumed to exist everywhere in each slab to replace the boundary shearing force. For the classical Saint-Venant (1871) model, this body-force can be shown to have a constant distribution in the vertical direction, and therefore can be evaluated for use in the momentum differential equation. In the newer Dressler theory (1978), however, for unsteady flow over curved beds, it is proved here that a constant body-force distribution is not possible. Its variable distribution is determined as well as its magnitude for use in the curved-flow equations. This variable distribution acts to produce an equal resultant in every thin layer of fluid parallel to the bed in an angular wedge over the curved channel bed. The new curved-flow equations are therefore extended to include resistive effects.

  16. Resistance of single polyaniline fibers and their junctions measured by double-probe atomic force microscopy

    NASA Astrophysics Data System (ADS)

    Higuchi, Rintaro; Shingaya, Yoshitaka; Nakayama, Tomonobu

    2016-08-01

    Electrical properties of polyaniline (PANI) fibers are of our interest as a component of network materials. Using a multiple-probe atomic force microscope with tuning fork probes, we investigated the resistance of single PANI fibers and their cross-point junction where the fibers contact each other. The resistivity of single PANI fibers was measured to be on the order of 10 Ω cm, and the contact resistance between PANI fibers was on the order of GΩ. The resistances through single cross-point junctions between two PANI fibers were very much dependent on the experimental condition, that is, the cross-point junction is stabilized or destabilized by physically placing the probes onto the two fibers. This suggests the nanomechanical instability of the cross-point junctions and a possibility to construct strain-responsive PANI fiber networks.

  17. Analysis of the slider force calibration procedure for the British Pendulum Skid Resistance Tester

    NASA Astrophysics Data System (ADS)

    Hiti, Miha; Ducman, Vilma

    2014-02-01

    British Pendulum Skid Resistance Testers are being used for the determination of the slip/skid resistance of surfaces by laboratories all around the world in different fields. The instrument itself can give reproducible results; however, the comparison of results obtained by different instruments can show large deviations. This paper presents a comparison of the performance of four pendulum testers, the investigation of requirements in international standards and the analysis of the calibration procedure for the determination of the slider force/deflection characteristics. The slider force/deflection characteristics were measured manually and also automatically with a uniaxial tensile/compression testing machine using different techniques. The results highlight the importance of the slider force/deflection characteristic shape and its influence on the results indicated by the pendulum tester and outline inconsistencies in different international standards describing the same device and its requirements. Presented results show good reproducibility and comparability of the pendulum test results when calibration is performed with the assembled pendulum either manually or automatically, provided the stricter slider force characteristic envelope requirements are taken into consideration. The actual slider force should be stable from 1.5 mm deflection onwards.

  18. Overexpression of lncRNA NEAT1 mitigates multidrug resistance by inhibiting ABCG2 in leukemia

    PubMed Central

    Gao, Caihua; Zhang, Jianying; Wang, Qingyan; Ren, Chunhua

    2016-01-01

    Leukemia is a heterogeneous clonal disorder in which early hematopoietic cells fail to differentiate and do not undergo programmed cell death or apoptosis. Less than one-third of adult patients with leukemia are managed using current therapies due to the emergence of multidrug resistance (MDR), emphasizing the need for newer and more robust approaches. Recent reports have suggested that long non-coding RNAs (lncRNAs) contribute to selective gene expression and, hence, could be manipulated effectively to halt the progression of cancer. However, little is known regarding the role of lncRNA in leukemia. Nuclear paraspeckle assembly transcript 1 (NEAT1) is a nuclear-restricted lncRNA involved in the pathogenesis of certain types of cancer. Deregulated expression of NEAT1 has been reported in a number of human malignancies, including leukemia and other solid tumors. The present study aimed to characterize the role of NEAT1 in the regulation of MDR in leukemia. Using reverse transcription-quantitative polymerase chain reaction, it was demonstrated that NEAT1 messenger RNA (mRNA) expression levels were significantly downregulated in leukemia patient samples compared with those from healthy donors. Furthermore, NEAT1 mRNA expression was repressed in a number of leukemia cell lines, including K562, THP-1, HL-60 and Jurkat cells, compared with peripheral white blood control cells, consistent with the expression observed in patients with leukemia. In addition, the transfection of a NEAT1 overexpression plasmid into K562 and THP-1 leukemia cell lines alleviated MDR induced by cytotoxic agents, such as Alisertib and Bortezomib, through inhibition of ATP-binding cassette G2. Although more robust studies are warranted, the current findings provide the basis for the use of NEAT1 as a novel promising target in the treatment of leukemia. PMID:27446393

  19. Electrical resistivity of polypyrrole nanotube measured by conductive scanning probe microscope: The role of contact force

    NASA Astrophysics Data System (ADS)

    Park, J. G.; Lee, S. H.; Kim, B.; Park, Y. W.

    2002-12-01

    Polypyrrole (PPy) nanotubes were synthesized using the pores of track-etched polycarbonate membrane as a template. Its size depends on the pore diameter of template, range from 50 to 200 nm. Direct I-V measurements of PPy nanotube (diameter of 120 nm) deposited on Au were done using a metal-coated tapping-mode atomic-force-microscope tip. Linear I-V characteristics are observed, and the resistance is decreased as the contact force is increased. Using the Hertz model, the elastic modulus E and electrical resistivity ρ are estimated to be E˜1 GPa and ρ˜1 Ωcm. These values are consistent with those obtained in bulk PPy film.

  20. A biomechanical review of the techniques used to estimate or measure resistive forces in swimming.

    PubMed

    Sacilotto, Gina B D; Ball, Nick; Mason, Bruce R

    2014-02-01

    Resistive or drag forces encountered during free swimming greatly influence the swim performance of elite competitive swimmers. The benefits in understanding the factors which affect the drag encountered will enhance performance within the sport. However, the current techniques used to experimentally measure or estimate drag values are questioned for their consistency, therefore limiting investigations in these factors. This paper aims to further understand how the resistive forces in swimming are measured and calculated. All techniques outlined demonstrate both strengths and weaknesses in the overall assessment of free swimming. By reviewing all techniques in this area, the reader should be able to select which one is best depending on what researchers want to gain from the testing. PMID:24676518

  1. Supercoiled Minivector DNA resists shear forces associated with gene therapy delivery

    PubMed Central

    Catanese, D J; Fogg, J M; Schrock, D E; Gilbert, B E; Zechiedrich, L

    2012-01-01

    Supercoiled DNAs varying from 281 to 5302 bp were subjected to shear forces generated by aerosolization or sonication. DNA shearing strongly correlated with length. Typical sized plasmids (⩾3000 bp) degraded rapidly. DNAs 2000–3000 bp persisted ∼10 min. Even in the absence of condensing agents, supercoiled DNA <1200 bp survived nebulization, and increased forces of sonication were necessary to shear it. Circular vectors were considerably more resistant to shearing than linear vectors of the same length. DNA supercoiling afforded additional protection. These results show the potential of shear-resistant Minivector DNAs to overcome one of the major challenges associated with gene therapy delivery. PMID:21633394

  2. Normal values of total respiratory resistance and reactance determined by forced oscillations: influence of smoking.

    PubMed

    Làndsér, F J; Clément, J; Van de Woestijne, K P

    1982-05-01

    In 407 healthy male subjects, smokers and nonsmokers, the resistance and reactance of the respiratory system were determined between 4 and 24 Hz, using a forced oscillation technique. The values are significantly correlated with age, weight, height, FEV1, and vital capacity. After standardization of the data for the latter variables, there are no differences between smokers and nonsmokers. The technique thus lacks sensitivity for the detection of the effects of smoking. PMID:7075278

  3. Reversible force-resistivity behavior of thin films of the TTF-TCNQ family

    SciTech Connect

    Vollmann, W.; Sonntag, H.U.

    1997-05-01

    The electrical properties of vacuum sublimed thin films of TIF-TCNQ and its derivatives mainly are determined by electron barriers at grain boundaries. The electrical conductivity is thermal activated and exhibits a significant dependence on a force acting perpendicularly to the film plane. The sample resistance R decreases continuously with increasing force F. TCNQ thin films on steel show a similar R-F relation. The effect has been observed already at forces of 1 N, but also up to about 60 kN. An explanation of these phenomena is given by a grain boundary limited hopping mechanism with pressure dependent potential barrier width and height. Morphology investigations by SEM support the model.

  4. Evaluation of the forced oscillation technique for the determination of resistance to breathing

    PubMed Central

    Fisher, Aron B.; DuBois, Arthur B.; Hyde, Richard W.

    1968-01-01

    Total respiratory resistance (RT) was measured by the application of a sine wave of airflow to the mouth at the resonant frequency of the respiratory system. The mean respiratory resistance of 42 normal subjects, measured at a mean functional residual capacity of 3.3 liters, was 2.3, SD ± 0.5, cm H2O/liter per sec, and the resonant frequency was between 5 and 8 cycle/sec. The airway resistance measured in these same subjects with the body plethysmograph at a mean panting thoracic gas volume of 3.5 liters was 1.3, SD ± 0.3, cm H2O/liter per sec. Total respiratory resistance was found to vary inversely with lung volume (V) measured plethysmographically; prediction formulae for normal subjects based on this relationship are: RT (mean) = 7.1/V, RT (range) = 4.0/V to 11.6/V where V is in liters and RT is in cm H2O/liter per sec. When these criteria were applied to subjects with thoracic disease the following results were obtained: 17 subjects with obstructive lung disease all had elevated total respiratory resistance; 9 subjects with diffuse lung disease without airway obstruction all had normal respiratory resistance; all but 1 of 5 obese subjects and all but 2 of a heterogeneous group of 9 subjects without airway obstruction had normal respiratory resistance. Failure to take lung volume into account resulted in a considerable decrease in the ability to discriminate between obstructive and nonobstructive lung disease on the basis of the forced oscillation test. The resonant frequency of the respiratory system of patients with obesity or nonobstructive lung disease was similar to that obtained in the normal group; accurate evaluation of resonant frequency in subjects with obstructive lung disease was frequently not possible. The combined resistances of lung, thoracic wall and abdominal tissues were found to account for less than 43% of the total respiratory resistance in normal subjects and were only slightly increased by the presence of obesity, restrictive diseases

  5. Force and power characteristics of a resistive exercise device for use in space

    NASA Astrophysics Data System (ADS)

    Berg, Hans E.; Tesch, Per A.

    We have developed a non-gravity dependent mechanical device, which provides resistance during coupled concentric and eccentric muscle actions, through the inertia of a spinning fly-wheel (Fly-Wheel Ergometry; FWE). Our research shows that lower-limb FWE exercise can produce forces and thus muscular stress comparable to what is typical of advanced resistance training using free weights. FWE also offers greater training stimuli during eccentric relative to concentric muscle actions, as evidenced by force and electromyographic (EMG) measurements. Muscle use of specific muscle groups, as assessed by the exercise-induced contrast shift of magnetic resonance images, is similar during lower-limb FWE and the barbell squat. Unlike free-weight exercise, FWE allows for maximal voluntary effort in each repetition of an exercise bout. Likewise, FWE exercise, not unassisted free-weight exercise, produces eccentric "overload". Collectively, the inherent features of this resistive exercise device and the results of the physiological evaluations we have performed, suggest that resistance exercise using FWE could be used as an effective exercise counter-measure in space. The flywheel principle can be employed to any exercise configuration and designed into a compact device allowing for exercises stressing those muscles and bone structures, which are thought to be most affected by long-duration spaceflight.

  6. NACE Task Force T-1 F-24 report on SSC resistance of weldments

    SciTech Connect

    Vitale, D.D.

    1998-12-31

    This report summarizes the testing program of NACE Task Force T-1 F-24 addressing the sulfide stress cracking resistance (SSC) of weldments. Three alloys were welded, postweld heat treated (PWHT), and tested for resistance to sulfide stress cracking (SSC) The alloys tested included AISI 4130, 2 1/4 Cr-1Mo, and Type 410 stainless steel. Resistance to SSC was evaluated using NACE TM0177 procedure. Performance of welded specimens was compared to base metal samples. The welding and PWHT procedures used were similar to those successfully used in industry practice today. With the exception of a lower strength, normalized, 2 1/4 Cr-1Mo weldments, the SSC of weldments was less than that of the base metal.

  7. Defense Waste Processing Facility: Report of task force on options to mitigate the effect of nitrite on DWPF operations. Savannah River Site 200-S Area

    SciTech Connect

    Randall, D.; Marek, J.C.

    1992-03-01

    The possibility of accumulating ammonium nitrate (an explosive) as well as organic compounds in the DWPF Chemical Processing Cell Vent System was recently discovered. A task force was therefore organized to examine ways to avoid this potential hazard. Of thirty-two processing/engineering options screened, the task force recommended five options, deemed to have the highest technical certainty, for detailed development and evaluation: Radiolysis of nitrite in the tetraphenylborate precipitate slurry feed in a new corrosion-resistant facility. Construction of a Late Washing Facility for precipitate washing before transfer to the DWPF; ``Just-in-Time`` precipitation; Startup Workaround by radiolysis of nitrite in the existing corrosion-resistant Pump Pit tanks; Ammonia venting and organics separation in the DWPF; and, Estimated costs and schedules are included in this report.

  8. Analysis of the effect of mechanical strength of the resist film on pattern collapse behavior using atomic force microscope

    NASA Astrophysics Data System (ADS)

    Tamada, Osamu; Goto, Tomohiro; Sanada, Masakazu; Moriuchi, Takahiro; Niiyama, Takayoshi; Kawai, Akira

    2006-03-01

    Recently, pattern collapse is becoming one of the critical issues in semiconductor manufacturing and many works have been done to solve this issue1) 2). Since pattern collapse occurs when outer force onto the resist pattern such as surface tension, impact of rinse solution, etc. surpasses the resistance of the resist pattern such as mechanical strength, adhesion force between resist and substrate, it is considered effective for improvement of pattern collapse to control resist film properties by track process, i.e., optimization of the mechanical properties of the resist film and enhancement of the adhesion force between resist and substrate 3) -5). In this study, we focused on the mechanical strength of the resist film and examined how post applied bake (PAB) condition affects the pattern collapse behavior. From ellipsometry measurement, it was found that increasing PAB time and temperature resulted in thickness reduction and refractive index increase, which suggested that the density of the resist film became high. Then we analyzed the mechanical strength of the resist film with the tip indentation method using atomic force microscope. It was found that the hardness of the resist film was affected by PAB conditions and regardless of PAB condition, hardened layer existed beneath the film surface. Finally, we carried out the measurements of loads to collapse 180nm resist dot patterns using the direct peeling with atomic force microscope tip (DPAT) method. Loads ranged from 600 to 2000nN overall and essentially increased as seen for indentation measurements when PAB temperature or time was increased, except some critical conditions. Through these evaluations using AFM, we succeeded in quantitatively evaluate the mechanical properties of the resist films processed with various PAB conditions. It was found that PAB condition obviously impacts on the hardness of the resist film and it is closely related to pattern collapse load.

  9. Swimming and running through sand: resistive force theory in granular media

    NASA Astrophysics Data System (ADS)

    Goldman, Daniel

    2013-11-01

    Resistive force theory (RFT) is often used to analyze the movement of microscopic organisms swimming in fluids. In RFT, a body is partitioned into infinitesimal segments, each of which generates thrust and experiences drag. Linear superposition of forces from elements over the body allows prediction of swimming kinematics and kinetics. While RFT does not always show quantitative agreement with experimental measurements in fluids [e.g. Rodenborn et al., PNAS, 2013], we show that it quantitatively models the locomotion of animals and robots that move on and within dry granular media. RFT shows excellent agreement when the medium is slightly polydisperse, in the regime where frictional forces dominate material inertial forces, and when locomotion can be approximated as confined to a plane. Within a given plane (horizontal or vertical) relationships that govern the force versus orientation of an elemental intruder are functionally independent of the granular medium. We use RFT to explain features of locomotion-these include muscle activation patterns during sand-swimming by the sandfish lizard and optimum limb shape for legged robot walking. Work supported by NSF and ARL.

  10. Granular resistive force theory explains the neuromechanical phase lag during sand-swimming

    NASA Astrophysics Data System (ADS)

    Ding, Yang; Sharpe, Sarah; Goldman, Daniel

    2012-11-01

    Undulatory locomotion is a common gait used by a diversity of animals in a range of environments. This mode of locomotion is characterized by the propagation of a traveling wave of body bending, which propels the animal in the opposite direction of the wave. Previous studies of undulatory locomotion in fluids, on land, and even within sand revealed that the wave of muscle activation progresses faster than the traveling wave of curvature. This leads to an increasing phase lag between activation and curvature at more posterior segments, known as the neuromechanical phase lag. In this study, we compare biological measurements of phase lag during the sand-swimming of the sandfish lizard to predictions of a simple model of undulatory swimming that consists of prescribed kinematics and granular resistive forces. The neuromechanical phase lag measured using electromyography (EMG) quantitatively matches the predicted phase lag between the local body curvature and torque exerted by granular resistive forces. Two effects are responsible for the phase lag in this system: the yaw motion of the body and different integration length over a traveling force pattern for different positions along the body.

  11. Cortical Activity during a Highly-Trained Resistance Exercise Movement Emphasizing Force, Power or Volume

    PubMed Central

    Flanagan, Shawn D.; Dunn-Lewis, Courtenay; Comstock, Brett A.; Maresh, Carl M.; Volek, Jeff S.; Denegar, Craig R.; Kraemer, William J.

    2012-01-01

    Cortical activity is thought to reflect the biomechanical properties of movement (e.g., force or velocity of movement), but fatigue and movement familiarity are important factors that require additional consideration in electrophysiological research. The purpose of this within-group quantitative electroencephalogram (EEG) investigation was to examine changes in cortical activity amplitude and location during four resistance exercise movement protocols emphasizing rate (PWR), magnitude (FOR), or volume (VOL) of force production, while accounting for movement familiarity and fatigue. EEG signals were recorded during each complete repetition and were then grouped by functional region, processed to eliminate artifacts, and averaged to compare overall differences in the magnitude and location of cortical activity between protocols over the course of six sets. Biomechanical, biochemical, and exertional data were collected to contextualize electrophysiological data. The most fatiguing protocols were accompanied by the greatest increases in cortical activity. Furthermore, despite non-incremental loading and lower force levels, VOL displayed the largest increases in cortical activity over time and greatest motor and sensory activity overall. Our findings suggest that cortical activity is strongly related to aspects of fatigue during a high intensity resistance exercise movement. PMID:24961265

  12. Cyclic Fatigue Resistance and Force Generated by OneShape Instruments during Curved Canal Preparation

    PubMed Central

    Zhang, Xiaolei

    2016-01-01

    Objectives To evaluate the cyclic fatigue resistance and the force generated by OneShape files during preparation of simulated curved canals. Methods Six OneShape files (the test) and six ProTaper F2 files (the control) were subject to the bending ability test. Another thirty files of each type were used to prepare artificial canals (n = 60), which were divided into 3 groups according to respective curvatures of the canals (30°, 60°, and 90°). The numbers of cycles to fatigue (NCF) as well as the positive and negative forces that were generated by files during canal preparation were recorded. The scanning electron microscopy was applied to detect the fracture surfaces. Results Compared with ProTaper F2 files, the bending loads of OneShape files were significantly lower at deflections of 45°(P < .05), 60° (P < .05) and 75° (P < .01). No significant difference was found at 30°. OneShape files presented a higher NCF in both 60° and 90° canals than the control (P < .01). No significant difference of NCF was found between OneShape and ProTaper files in 30° canals. During the preparation of 30° canals by both files, the negative forces were dominant. With the increase of the curvature, more positive forces were observed. When the OneShape Files were compared with the control, significant different forces were found at D3 and D2 (P < .05) in 30° canals, at D2 (P < .05), D1 (P < .01) and D0 (P < .01) in 60° canals, and at D4 and D3 (P < .01) in 90° canals. Conclusions OneShape files possessed a reliable flexibility and cyclic fatigue resistance. According to the assessments of the forces generated by files, OneShape instruments performed in a more fatigue-resistant way during curved canal preparation, compared with the ProTaper F2 files. PMID:27513666

  13. High force development augments skeletal muscle signalling in resistance exercise modes equalized for time under tension.

    PubMed

    Gehlert, Sebastian; Suhr, Frank; Gutsche, Katrin; Willkomm, Lena; Kern, Julia; Jacko, Daniel; Knicker, Axel; Schiffer, Thorsten; Wackerhage, Henning; Bloch, Wilhelm

    2015-06-01

    How force development and time under tension (TUT) during resistance exercise (RE) influence anabolic signalling of skeletal muscle is incompletely understood. We hypothesized that high force development during RE is more important for post-exercise-induced signalling than submaximal and fatiguing RE with lower force development but similar TUT. Twenty-two male subjects (24 ± 6 years, 181 ± 9 cm, 79 ± 2 kg) performed three distinct RE modes in the fed state with equal TUT but distinct force output: (i) maximal eccentric RE (ECC, n = 7) three sets, eight reps, 100% eccentric dynamic force; (ii) standard RE (STD, n = 7), three sets, 10 reps, 75% dynamic force; and (iii) high fatiguing single-set RE (HIT, n = 8), 20 reps, 100% eccentric-concentric force; vastus lateralis biopsies were collected at baseline, 15, 30, 60, 240 min and 24 h after RE, and the signalling of mechanosensitive and mammalian target of rapamycin (mTOR)-related proteins was determined. The phosphorylation levels of pFAK(Tyr397), pJNK(Thr183/Tyr185), pAKT(Thr308/Ser473), pmTOR(Ser2448), p4E-BP1(Thr37/46), p70s6k(Thr389)/(Ser421/Thr424) and pS6(Ser235/236) were significantly higher in ECC than those in STD and HIT at several time points (P < 0.01). pJNK(Thr183/Tyr185) and pS6(Ser235/236) levels were significantly higher in type II myofibres in ECC compared with STD and HIT. HIT exerted throughout the weakest signalling response. We conclude that high force development during acute RE is superior for anabolic skeletal muscle signalling than fatiguing RE with lower force output but similar TUT. Our results suggest that this response is substantially driven by the higher activation of type II myofibres during RE. PMID:25070178

  14. Forced and voluntary exercise counteract insulin resistance in rats: the role of coping style.

    PubMed

    Boersma, Gretha J; Barf, R Paulien; Benthem, Lambertus; van Dijk, Gertjan; Scheurink, Anton J W

    2012-06-01

    There are large individual differences in the success rates of exercise intervention programs aimed at the prevention and treatment of obesity-related disorders. In the present study, we tested the hypothesis that differences in coping style may impact the success rates of these intervention programs. We tested insulin responses before and after voluntary wheel running in both passive (insulin resistant) Roman Low Avoidance (RLA) and proactive (insulin sensitive) Roman High Avoidance (RHA) rats using intravenous glucose tolerance tests (IVGTTs). To control for a potential difference between voluntary and forced exercise, we also included RLA and RHA rats that were subjected to forced running. We found the following: 1) when given the opportunity to run voluntarily in a running wheel, passive RLA rats run more than proactively than RHA rats; 2) voluntary exercise leads to a normalization of insulin responses during an IVGTTs in RLA rats; and 3) there were no behavioral and physiological differences in efficacy between voluntary and forced running. We conclude that exercise, both forced and voluntary, is a successful lifestyle intervention for the treatment of hyperinsulinemia, especially in individuals with a passive coping style. PMID:22609426

  15. Unraveling the genetic driving forces enabling antibiotic resistance at the single cell level

    NASA Astrophysics Data System (ADS)

    Bos, Julia

    Bacteria are champions at finding ways to quickly respond and adapt to environments like the human gut, known as the epicentre of antibiotic resistance. How do they do it? Combining molecular biology tools to microfluidic and fluorescence microscopy technologies, we monitor the behavior of bacteria at the single cell level in the presence of non-toxic doses of antibiotics. By tracking the chromosome dynamics of Escherichia coli cells upon antibiotic treatment, we examine the changes in the number, localization and content of the chromosome copies within one cell compartment or between adjacent cells. I will discuss how our work pictures the bacterial genomic plasticity as a driving force in evolution and how it provides access to the mechanisms controlling the subtle balance between genetic diversity and stability in the development of antibiotic resistance.

  16. Screening in nanowires and nanocontacts: field emission, adhesion force, and contact resistance

    SciTech Connect

    Zhang, Xiaoguang; Pantelides, Sokrates T.

    2009-01-01

    The explanations of several nanoscale phenomena such as the field enhancement factor in field emission, the large decay length of the adhesion force between a metallic tip and a surface, and the contact resistance in a nanowire break junction have been elusive. Here we develop an analytical theory of Thomas-Fermi screening in nanoscale structures. We demonstrate that nanoscale dimensions give rise to an effective screening length that depends on geometry and physical boundary conditions. The above phenomena are shown to be manifestations of the effective screening length.

  17. Inorganic resist materials based on zirconium phosphonate for atomic force microscope lithography

    NASA Astrophysics Data System (ADS)

    Kang, Mankyu; Kim, Seonae; Jung, JinHyuck; Kim, Heebom; Shin, Inkyun; Jeon, Chanuk; Lee, Haiwon

    2014-03-01

    New inorganic resist materials based on metal complexes were investigated for atomic force microscope (AFM) lithography. Phosphoric acids are good for self-assembly because of their strong binding energy. In this work, zirconium phosphonate system are newly synthesized for spin-coatable materials in aqueous solutions and leads to negative tone pattern for improving line edge roughness. Low electron exposure by AFM lithography could generate a pattern by electrochemical reaction and cross-linking of metal-oxo complexes. It has been reported that the minimum pattern results are affected by lithographic speed, and the applied voltage between a tip and a substrate.

  18. Effects of resistance training on tendon mechanical properties and rapid force production in prepubertal children

    PubMed Central

    Waugh, C. M.; Korff, T.; Fath, F.

    2014-01-01

    Children develop lower levels of muscle force, and at slower rates, than adults. Although strength training in children is expected to reduce this differential, a synchronous adaptation in the tendon must be achieved to ensure forces continue to be transmitted to the skeleton with efficiency while minimizing the risk of strain-related tendon injury. We hypothesized that resistance training (RT) would alter tendon mechanical properties in children concomitantly with changes in force production characteristics. Twenty prepubertal children (age 8.9 ± 0.3 yr) were equally divided into control (nontraining) and experimental (training) groups. The training group completed a 10-wk RT intervention consisting of 2–3 sets of 8–15 plantar flexion contractions performed twice weekly on a recumbent calf-raise machine. Achilles tendon properties (cross-sectional area, elongation, stress, strain, stiffness, and Young's modulus), electromechanical delay (EMD; time between the onset of muscle activity and force), rate of force development (RFD; slope of the force-time curve), and rate of electromyographic (EMG) increase (REI; slope of the EMG time curve) were measured before and after RT. Tendon stiffness and Young's modulus increased significantly after RT in the experimental group only (∼29% and ∼25%, respectively); all other tendon properties were not significantly altered, although there were mean decreases in both peak tendon strain and strain at a given force level (14% and 24%, respectively; not significant) which may have implications for tendon injury risk and muscle fiber mechanics. A decrease of ∼13% in EMD was found after RT for the experimental group, which paralleled the increase in tendon stiffness (r = −0.59); however, RFD and REI were unchanged. The present data show that the Achilles tendon adapts to RT in prepubertal children and is paralleled by a change in EMD, although the magnitude of this change did not appear to be sufficient to influence RFD

  19. Increase in Mechanical Resistance to Force in a Shear-Activated Protein

    NASA Astrophysics Data System (ADS)

    Botello, Eric; Harris, Nolan; Choi, Huiwan; Zhou, Zhou; Bergeron, Angela; Dong, Jing-Fei; Kiang, Ching-Hwa

    2009-03-01

    von Willebrand factor (VWF) is the largest multimeric adhesion ligand found in human blood. Plasma VWF (pVWF) must be exposed to shear stress, like at sites of vascular injury, to be activated to bind platelets to induce blood clotting. In addition, adhesion activity of VWF is related to its polymer size, with the ultra-large form of VWF (ULVWF) being hyper-active, and forming fibers even without exposure to shear stress. We used the AFM to stretch pVWF, sheared VWF (sVWF) and ULVWF, and monitor the forces as a function of molecular extension. We showed a similar increase in force resistance to unfolding for sVWF and ULVWF when compared to pVWF. The increase in force is reduced when other molecules that are known to disrupt their fibril formation are present. Our results provide evidence that the common higher order structure of sVWF and ULVWF may affect the domain structure that causes difference in their adhesion activity compared to pVWF.

  20. Effects of fast-velocity eccentric resistance training on early and late rate of force development.

    PubMed

    Oliveira, Anderson Souza; Corvino, Rogério Bulhões; Caputo, Fabrizio; Aagaard, Per; Denadai, Benedito Sérgio

    2016-01-01

    This study examined whether short-term maximal resistance training employing fast-velocity eccentric knee extensor actions would induce improvements in maximal isometric torque and rate of force development (RFD) at early (<100 ms) and late phases (>100 ms) of rising torque. Twenty healthy men were assigned to two experimental groups: eccentric resistance training (TG) or control (CG). Participants on the TG trained three days a week for a total of eight weeks. Training consisted of maximal unilateral eccentric knee extensors actions performed at 180 °s-1. Maximal isometric knee extensor torque (MVC) and incremental RFD in successive 50 ms time-windows from the onset contraction were analysed in absolute terms (RFDINC) or when normalised relative to MVC (RFDREL). After eight weeks, TG demonstrated increases in MVC (28%), RFDINC (0-50 ms: 30%; 50-100 ms: 31%) and RFDREL (0-50 ms: 29%; 50-100 ms: 32%). Moreover, no changes in the late phase of incremental RFD were observed in TG. No changes were found in the CG. In summary, we have demonstrated, in active individuals, that a short period of resistance training performed with eccentric fast-velocity isokinetic muscle contractions is able to enhance RFDINC and RFDREL obtained at the early phase of rising joint torque. PMID:25695853

  1. Mitigation of Resistance Through Mixtures of Traditional Pesticides, Anti-tick Vaccines, and New Acaricides Developed by the Pharmaceutical Industry

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Over the past 70 years, the southern cattle tick, Rhipicephalus (Boophilus) microplus, has developed resistance to every acaricide available for its control. Recently, populations of R. microplus have evolved simultaneous resistance to multiple classes of acaricides. These multi-resistant population...

  2. Estimation of random errors in respiratory resistance and reactance measured by the forced oscillation technique.

    PubMed

    Farré, R; Rotger, M; Navajas, D

    1997-03-01

    The forced oscillation technique (FOT) allows the measurement of respiratory resistance (Rrs) and reactance (Xrs) and their associated coherence (gamma2). To avoid unreliable data, it is usual to reject Rrs and Xrs measurements with a gamma2 <0.95. This procedure makes it difficult to obtain acceptable data at the lowest frequencies of interest. The aim of this study was to derive expressions to compute the random error of Rrs and Xrs from gamma2 and the number (N) of data blocks involved in a FOT measurement. To this end, we developed theoretical equations for the variances and covariances of the pressure and flow auto- and cross-spectra used to compute Rrs and Xrs. Random errors of Rrs and Xrs were found to depend on the values of Rrs and Xrs, and to be proportional to ((1-gamma2)/(2 x N x gamma2))1/2. Reliable Rrs and Xrs data can be obtained in measurements with low gamma2 by enlarging the data recording (i.e. N). Therefore, the error equations derived may be useful to extend the frequency band of the forced oscillation technique to frequencies lower than usual, characterized by low coherence. PMID:9073006

  3. Atomic force microscopy study of the antibacterial effect of fosfomycin on methicillin-resistant Staphylococcus pseudintermedius

    NASA Astrophysics Data System (ADS)

    Neethirajan, Suresh; DiCicco, Matthew

    2014-08-01

    The influence of fosfomycin on methicillin-resistant Staphylococcus pseudintermedius (MRSP) as the target cell was studied by atomic force microscopy (AFM). Nanoscale images of the effects of the antibiotic fosfomycin on this gram-positive bacterium's cell were obtained in situ without fixing agents. Our study has demonstrated substantial morphological and topographical differences between the control and fosfomycin-treated MRSP cells. The AFM investigations further revealed the rough surface morphology and a 30 % shrinkage in size of the fosfomycin-treated cell and the leakage of cytoplasmic components from the cell. The damage of cell membrane integrity and the cell surface degradation as observed elaborates the antibacterial activity of fosfomycin. The AFM image analysis also reveals that the fosfomycin inhibits cell division, and prevents the adhesion on the surface discouraging the biofilm attachment. The micro-titre plate assay results conform to the atomic force microscopy image analysis. This is the first visual demonstration of the effect of fosfomycin on MRSP cells.

  4. Quantification of the resist dissolution process: an in situ analysis using high speed atomic force microscopy

    NASA Astrophysics Data System (ADS)

    Santillan, Julius Joseph; Shichiri, Motoharu; Itani, Toshiro

    2016-03-01

    This work focuses on the application of a high speed atomic force microscope (HS-AFM) for the in situ visualization / quantification of the resist dissolution process. This technique, as reported in the past, has provided useful pointers on the formation of resist patterns during dissolution. This paper discusses about an investigation made on the quantification of what we refer to as "dissolution unit size" or the basic units of patterning material dissolution. This was done through the establishment of an originally developed analysis method which extracts the difference between two succeeding temporal states of the material film surface (images) to indicate the amount of change occurring in the material film at a specific span of time. Preliminary experiments with actual patterning materials were done using a positive-tone EUV model resist composed only of polyhydroxystyrene (PHS)-based polymer with a molecular weight of 2,500 and a polydispersity index of 1.2. In the absence of a protecting group, the material was utilized at a 50nm film thickness with post application bake of 90°C/60s. The resulting film is soluble in the alkali-based developer even without exposure. Results have shown that the dissolution components (dissolution unit size) of the PHS-based material are not of fixed size. Instead, it was found that aside from one constantly dissolving unit size, another, much larger dissolution unit size trend also occurs during material dissolution. The presence of this larger dissolution unit size suggests an occurrence of "polymer clustering". Such polymer clustering was not significantly present during the initial stages of dissolution (near the original film surface) but becomes more persistently obvious after the dissolution process reaches a certain film thickness below the initial surface.

  5. Impact and mitigation of borehole related effects in permanent crosshole resistivity imaging: An example from the Ketzin CO2 storage site

    NASA Astrophysics Data System (ADS)

    Wagner, Florian M.; Bergmann, Peter; Rücker, Carsten; Wiese, Bernd; Labitzke, Tim; Schmidt-Hattenberger, Cornelia; Maurer, Hansruedi

    2015-12-01

    Geoelectrical methods are particularly suited for CO2 injection monitoring due to their high sensitivity to fluid displacement processes in porous rock formations. The use of borehole electrodes is favorable for deep storage horizons. Yet data acquisition based on permanently installed borehole electrodes can be challenged by the finite extent of the electrodes, unintended borehole deviation and complex borehole completion. Such conditions can lead to systematic errors in the electrical data sets, distortions of tomograms, and ultimately misinterpretations. We systematically analyze the effects of different borehole related error sources on tomographic inversion results and present respective methods for mitigation. Specifically, we incorporate the finite extent of the ring electrodes and the borehole completion into the electrical finite-element models and discuss the opportunity to infer borehole deviations solely based on geoelectrical data by means of a coupled inversion. While the finite extent of ring electrodes can be neglected if the electrode spacing is sufficiently large (> 5 m), different borehole completion materials used to fill the well annulus can cause potentially strong resistivity contrasts between the borehole completion and the rock formation, i.e., close to the electrodes. Resulting inversion artifacts are generally less severe when the borehole completion is more resistive compared to the surrounding rock. It is also shown that 2.5D inversion approaches are not adequate for imaging injection experiments in the presence of borehole completion. Unintended borehole deviation can result in geometric errors. Especially, vertical electrode shifts cause strong and localized inversion artifacts. Coupled inverse schemes potentially provide the opportunity to infer electrode shifts solely based on geoelectrical data provided the availability of high quality measurements (< 5% data error). After discussing the effects of the different borehole related

  6. Mitigation of Insulin Resistance by Mangiferin in a Rat Model of Fructose-Induced Metabolic Syndrome Is Associated with Modulation of CD36 Redistribution in the Skeletal Muscle.

    PubMed

    Zhou, Liang; Pan, Yongquan; Chonan, Ritsu; Batey, Robert; Rong, Xianglu; Yamahara, Johji; Wang, Jianwei; Li, Yuhao

    2016-01-01

    Mangiferin is one of the prominent active components responsible for the antidiabetic property of many traditional herbs, but its underlying mechanisms of action remain unclear. CD36 in skeletal muscle is known to contribute to the etiology of insulin resistance by facilitating fatty acid uptake. This study investigated the effect of mangiferin on insulin resistance. The results showed that treatment of Wistar-Kyoto rats with mangiferin (15 mg/kg, once daily, by oral gavage) for 7 weeks inhibited chronic liquid fructose consumption-induced increases in plasma insulin concentrations at the baseline and during oral glucose tolerance test (OGTT), and the homeostasis model assessment of insulin resistance index. It also suppressed the increases in fasted plasma nonesterified fatty acid (NEFA) concentration and the adipose tissue insulin resistance index. Mechanistically, mangiferin neither affected intakes of fructose and chow, and the increase in epididymal and perirenal fat, nor attenuated fructose-induced hypertension. In contrast, mangiferin attenuated fructose-induced acceleration of plasma NEFA clearance during OGTT, and tended to decrease excessive triglyceride accumulation in gastrocnemius. Immunofluorescence staining and subsequent rating of CD36-expressing fibers in gastrocnemius revealed that mangiferin restored fructose-stimulated sarcolemmal CD36 overexpression and decreased intracellular CD36 distribution. In addition, the effects of mangiferin on the parameters associated with insulin resistance and abnormal fatty acid metabolism were absent in the spontaneously hypertensive rats carrying numerous nonfunctional mutations in the CD36 gene. Thus, these results suggest that mangiferin treatment mitigates insulin resistance in a rat model of fructose-induced metabolic syndrome by modulating sarcolemmal and intracellular CD36 redistribution in the skeletal muscle. PMID:26498906

  7. 77 FR 58143 - Interagency Task Force on Antimicrobial Resistance (ITFAR): An Update of A Public Health Action...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-09-19

    ... resistance. Action items were organized into four focus areas: Surveillance, Prevention and Control, Research.... Other HHS Task Force members include the Agency for Healthcare Research and Quality (AHRQ), the Centers..., Prevention and Control, Research, and Product Development. Written comments should be submitted following...

  8. Double minute chromosomes in mouse methotrexate-resistant cells studied by atomic force microscopy

    SciTech Connect

    Deng Xinyu; Zhang Liangyu; Zhang Yu; Yan Yongda; Xu Zongwei; Dong Shen; Fu Songbin . E-mail: fusb@ems.hrbmu.edu.cn

    2006-08-11

    Double minute chromosomes (DMs) are acentric, autonomously replicating extra-chromosomes and frequently mediate gene amplification in tumor and drug resistant cells. Atomic force microscopy (AFM) is a powerful tool in microbiology. We used AFM to explore the ultrastructure of DMs in mouse fibroblasts 3T3R500. DMs in various phases of cell cycle were also studied in order to elucidate the mechanisms of their duplication and separation. Metaphase spread and induced premature condensed chromosomes (PCCs) were observed under the AFM. DMs were detected to be composed of two compact spheres linked by fibers. The fibers of DMs directly connected with metaphase chromosomes were observed. Many single-minutes and few DMs were detected in G1 PCCs, while more DMs were detected in S PCCs than in G1 PCCs. Besides, all of the DMs in G2 PCCs were coupled. Our present results suggested that DMs might divide into single-minutes during or before G1-phase, followed by duplication of the single-minutes in S-phase. Moreover, we introduced a new powerful tool to study DMs and got some ideal results.

  9. Force production during squats performed with a rotational resistance device under stable versus unstable conditions.

    PubMed

    Moras, Gerard; Vázquez-Guerrero, Jairo

    2015-11-01

    [Purpose] Force production during a squat action on a rotational resistance device (RRD) under stable and unstable conditions. [Subjects and Methods] Twenty-one healthy males were asked to perform six sets of six repetitions of squats on an RRD on either stable or unstable surfaces. The stable and unstable sets were performed on different days. Muscular outputs were obtained from a linear encoder and a strain gauge fixed to a vest. [Results] Overall, the results showed no significant differences for any of the dependent variables across exercise modes. Forcemean outputs were higher in the concentric phase than in the eccentric phase for each condition, but there were no differences in velocity, time or displacement. The forcepeak was similar in the eccentric and concentric phases of movement under both stable and unstable conditions. There were no significant differences in forcemean between sets per condition or between conditions. [Conclusion] These results suggest that performing squats with a RRD achieves similar forcemean and forcepeak under stable and unstable conditions. The forcepeak produced is also similar in concentric and eccentric phases. PMID:26696707

  10. Force production during squats performed with a rotational resistance device under stable versus unstable conditions

    PubMed Central

    Moras, Gerard; Vázquez-Guerrero, Jairo

    2015-01-01

    [Purpose] Force production during a squat action on a rotational resistance device (RRD) under stable and unstable conditions. [Subjects and Methods] Twenty-one healthy males were asked to perform six sets of six repetitions of squats on an RRD on either stable or unstable surfaces. The stable and unstable sets were performed on different days. Muscular outputs were obtained from a linear encoder and a strain gauge fixed to a vest. [Results] Overall, the results showed no significant differences for any of the dependent variables across exercise modes. Forcemean outputs were higher in the concentric phase than in the eccentric phase for each condition, but there were no differences in velocity, time or displacement. The forcepeak was similar in the eccentric and concentric phases of movement under both stable and unstable conditions. There were no significant differences in forcemean between sets per condition or between conditions. [Conclusion] These results suggest that performing squats with a RRD achieves similar forcemean and forcepeak under stable and unstable conditions. The forcepeak produced is also similar in concentric and eccentric phases. PMID:26696707

  11. Memory programming of TiO2-x films by Conductive Atomic Force Microscopy evidencing filamentary resistive switching

    NASA Astrophysics Data System (ADS)

    Bousoulas, P.; Giannopoulos, J.; Giannakopoulos, K.; Dimitrakis, P.; Tsoukalas, D.

    2015-03-01

    Resistive Random Access Memory (RRAM) with a structure Au/Ti/TiO2-x/Au demonstrated a clear bipolar resistive switching behavior without the necessity of an initial electroforming process. The titanium oxide (TiO2-x) thin film was deposited by reactive RF magnetron sputtering at room temperature in a controlled oxygen/argon ambient. The high density of oxygen vacancies within the film (induced by the low oxygen content) is an essential component for the formation of conducting filaments and demonstration of DC or nanosecond pulsed resistance switching, but also impose limitations for the conduction behavior of the high resistance state. Conductive Atomic Force Microscopy (C-AFM) was then employed in order to investigate the nanoscale electrical properties of our device. In situ current distribution during the SET process disclosed possible formation of conducting filaments while DC sweeping bias voltage revealed an OFF/ON switching ratio of about 200. We have also demonstrated that by using C-AFM both a low resistance state and a high resistance state can be written by bipolar voltage application imaged by corresponding patterns on the TiO2-x current image, suggesting that oxygen ions movement at the Pt-Ir coated tip/TiO2-x interface plays a critical role in the resistive switching phenomenon and thus correlating the macroscopic characteristics of our device with its microscopic origins. Nanoscale resistance switching is also demonstrated by programming distinct patterns on the device's current image.

  12. Uniform Selection as a Primary Force Reducing Population Genetic Differentiation of Cavitation Resistance across a Species Range

    PubMed Central

    Lamy, Jean-Baptiste; Bouffier, Laurent; Burlett, Régis; Plomion, Christophe; Cochard, Hervé; Delzon, Sylvain

    2011-01-01

    Background Cavitation resistance to water stress-induced embolism determines plant survival during drought. This adaptive trait has been described as highly variable in a wide range of tree species, but little is known about the extent of genetic and phenotypic variability within species. This information is essential to our understanding of the evolutionary forces that have shaped this trait, and for evaluation of its inclusion in breeding programs. Methodology We assessed cavitation resistance (P50), growth and carbon isotope composition in six Pinus pinaster populations in a provenance and progeny trial. We estimated the heritability of cavitation resistance and compared the distribution of neutral markers (FST) and quantitative genetic differentiation (QST), for retrospective identification of the evolutionary forces acting on these traits. Results/Discussion In contrast to growth and carbon isotope composition, no population differentiation was found for cavitation resistance. Heritability was higher than for the other traits, with a low additive genetic variance (h2ns = 0.43±0.18, CVA = 4.4%). QST was significantly lower than FST, indicating uniform selection for P50, rather than genetic drift. Putative mechanisms underlying QST

  13. A Built-In Mechanism to Mitigate the Spread of Insect-Resistance and Herbicide-Tolerance Transgenes into Weedy Rice Populations

    PubMed Central

    Liu, Chengyi; Li, Jingjing; Gao, Jianhua; Shen, Zhicheng; Lu, Bao-Rong; Lin, Chaoyang

    2012-01-01

    Background The major challenge of cultivating genetically modified (GM) rice (Oryza sativa) at the commercial scale is to prevent the spread of transgenes from GM cultivated rice to its coexisting weedy rice (O. sativa f. spontanea). The strategic development of GM rice with a built-in control mechanism can mitigate transgene spread in weedy rice populations. Methodology/Principal Findings An RNAi cassette suppressing the expression of the bentazon detoxifying enzyme CYP81A6 was constructed into the T-DNA which contained two tightly linked transgenes expressing the Bt insecticidal protein Cry1Ab and the glyphosate tolerant 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS), respectively. GM rice plants developed from this T-DNA were resistant to lepidopteran pests and tolerant to glyphosate, but sensitive to bentazon. The application of bentazon of 2000 mg/L at the rate of 40 mL/m2, which is approximately the recommended dose for the field application to control common rice weeds, killed all F2 plants containing the transgenes generated from the Crop-weed hybrids between a GM rice line (CGH-13) and two weedy rice strains (PI-63 and PI-1401). Conclusions/Significance Weedy rice plants containing transgenes from GM rice through gene flow can be selectively killed by the spray of bentazon when a non-GM rice variety is cultivated alternately in a few-year interval. The built-in control mechanism in combination of cropping management is likely to mitigate the spread of transgenes into weedy rice populations. PMID:22359609

  14. Adipocyte-specific CD1d-deficiency mitigates diet-induced obesity and insulin resistance in mice.

    PubMed

    Satoh, Masashi; Hoshino, Miyuki; Fujita, Koki; Iizuka, Misao; Fujii, Satoshi; Clingan, Christopher S; Van Kaer, Luc; Iwabuchi, Kazuya

    2016-01-01

    It has been shown that CD1d expression and glycolipid-reactive, CD1d-restricted NKT cells exacerbate the development of obesity and insulin resistance in mice. However, the relevant CD1d-expressing cells that influence the effects of NKT cells on the progression of obesity remain incompletely defined. In this study, we have demonstrated that 3T3-L1 adipocytes can present endogenous ligands to NKT cells, leading to IFN-γ production, which in turn, stimulated 3T3-L1 adipocytes to enhance expression of CD1d and CCL2, and decrease expression of adiponectin. Furthermore, adipocyte-specific CD1d deletion decreased the size of the visceral adipose tissue mass and enhanced insulin sensitivity in mice fed a high-fat diet (HFD). Accordingly, NKT cells were less activated, IFN-γ production was significantly reduced, and levels of adiponectin were increased in these animals as compared with control mice on HFD. Importantly, macrophage recruitment into the adipose tissue of adipocyte-specific CD1d-deficient mice was significantly blunted. These findings indicate that interactions between NKT cells and CD1d-expressing adipocytes producing endogenous NKT cell ligands play a critical role in the induction of inflammation and functional modulation of adipose tissue that leads to obesity. PMID:27329323

  15. Adipocyte-specific CD1d-deficiency mitigates diet-induced obesity and insulin resistance in mice

    PubMed Central

    Satoh, Masashi; Hoshino, Miyuki; Fujita, Koki; Iizuka, Misao; Fujii, Satoshi; Clingan, Christopher S.; Van Kaer, Luc; Iwabuchi, Kazuya

    2016-01-01

    It has been shown that CD1d expression and glycolipid-reactive, CD1d-restricted NKT cells exacerbate the development of obesity and insulin resistance in mice. However, the relevant CD1d-expressing cells that influence the effects of NKT cells on the progression of obesity remain incompletely defined. In this study, we have demonstrated that 3T3-L1 adipocytes can present endogenous ligands to NKT cells, leading to IFN-γ production, which in turn, stimulated 3T3-L1 adipocytes to enhance expression of CD1d and CCL2, and decrease expression of adiponectin. Furthermore, adipocyte-specific CD1d deletion decreased the size of the visceral adipose tissue mass and enhanced insulin sensitivity in mice fed a high-fat diet (HFD). Accordingly, NKT cells were less activated, IFN-γ production was significantly reduced, and levels of adiponectin were increased in these animals as compared with control mice on HFD. Importantly, macrophage recruitment into the adipose tissue of adipocyte-specific CD1d-deficient mice was significantly blunted. These findings indicate that interactions between NKT cells and CD1d-expressing adipocytes producing endogenous NKT cell ligands play a critical role in the induction of inflammation and functional modulation of adipose tissue that leads to obesity. PMID:27329323

  16. Mechanobiology - chemical origin of membrane mechanical resistance and force-dependent signaling.

    PubMed

    Beedle, Amy E M; Williams, Aisling; Relat-Goberna, Josep; Garcia-Manyes, Sergi

    2015-12-01

    The cell membrane is a highly complex designed material with remarkable physicochemical properties; comprised mainly of lipid moieties, it is capable of self-assembling, changing morphology, housing a range of distinct proteins, and withstanding electrical, chemical and mechanical perturbations. All of these fundamental cellular functions occurring within a 5nm thick film is an astonishing feat of engineering, made possible due to the interplay of a variety of intermolecular forces. Elucidating how the interactions within the chemically distinct partners influence the nanomechanical properties of the membrane is essential to gain a comprehensive understanding of a wide-variety of both force-triggered and force-sensing mechanisms that dictate essential cellular processes. PMID:26517566

  17. Effect of brief daily resistance training on rapid force development in painful neck and shoulder muscles: randomized controlled trial

    PubMed Central

    Jay, Kenneth; schraefel, mc; Andersen, Christoffer H; Ebbesen, Frederik S; Christiansen, David H; Skotte, Jørgen; Zebis, Mette K; Andersen, Lars L

    2013-01-01

    Objective: To determine the effect of small daily amounts of progressive resistance training on rapid force development of painful neck/shoulder muscles. Methods: 198 generally healthy adults with frequent neck/shoulder muscle pain (mean: age 43·1 years, computer use 93% of work time, 88% women, duration of pain 186 day during the previous year) were randomly allocated to 2- or 12 min of daily progressive resistance training with elastic tubing or to a control group receiving weekly information on general health. A blinded assessor took measures at baseline and at 10-week follow-up; participants performed maximal voluntary contractions at a static 90-degree shoulder joint angle. Rapid force development was determined as the rate of torque development and maximal muscle strength was determined as the peak torque. Results: Compared with the control group, rate of torque development increased 31·0 Nm s−1 [95% confidence interval: (1·33–11·80)] in the 2-min group and 33·2 Nm s−1 (1·66–12·33) in the 12-min group from baseline to 10-week follow-up, corresponding to an increase of 16·0% and 18·2% for the two groups, respectively. The increase was significantly different compared to controls (P<0·05) for both training groups. Maximal muscle strength increased only ∼5–6% [mean and 95% confidence interval for 2- and 12-min groups to control, respectively: 2·5 Nm (0·05–0·73) and 2·2 Nm (0·01–0·70)]. No significant differences between the 2- and 12-min groups were evident. A weak but significant relationship existed between changes in rapid force development and pain (r = 0·27, P<0·01), but not between changes in maximal muscle strength and pain. Conclusion: Small daily amounts of progressive resistance training in adults with frequent neck/shoulder pain increases rapid force development and, to a less extent, maximal force capacity. PMID:23758661

  18. Wide range local resistance imaging on fragile materials by conducting probe atomic force microscopy in intermittent contact mode

    NASA Astrophysics Data System (ADS)

    Vecchiola, Aymeric; Chrétien, Pascal; Delprat, Sophie; Bouzehouane, Karim; Schneegans, Olivier; Seneor, Pierre; Mattana, Richard; Tatay, Sergio; Geffroy, Bernard; Bonnassieux, Yvan; Mencaraglia, Denis; Houzé, Frédéric

    2016-06-01

    An imaging technique associating a slowly intermittent contact mode of atomic force microscopy (AFM) with a home-made multi-purpose resistance sensing device is presented. It aims at extending the widespread resistance measurements classically operated in contact mode AFM to broaden their application fields to soft materials (molecular electronics, biology) and fragile or weakly anchored nano-objects, for which nanoscale electrical characterization is highly demanded and often proves to be a challenging task in contact mode. Compared with the state of the art concerning less aggressive solutions for AFM electrical imaging, our technique brings a significantly wider range of resistance measurement (over 10 decades) without any manual switching, which is a major advantage for the characterization of materials with large on-sample resistance variations. After describing the basics of the set-up, we report on preliminary investigations focused on academic samples of self-assembled monolayers with various thicknesses as a demonstrator of the imaging capabilities of our instrument, from qualitative and semi-quantitative viewpoints. Then two application examples are presented, regarding an organic photovoltaic thin film and an array of individual vertical carbon nanotubes. Both attest the relevance of the technique for the control and optimization of technological processes.

  19. On the concept of leaf boundary layer resistance for forced convection

    PubMed

    Vesala

    1998-09-01

    The definition of leaf boundary layer resistance is reconsidered in respect of the three-dimensional diffusion-controlled mass transport region just above the leaf surface. Due to the existence of this superstomatal air layer, the conventional convective boundary layer is not in direct contact with the surface. Thus, in terms of plant physiology, the diffusive "end correction" to the stomatal resistance should be included in the boundary layer resistance. This is true for laminar as well as turbulent flows. When the surface mole fraction of an exchanged gas is estimated using the boundary layer resistance ignoring the diffusive term may lead to a noticeable error. The self-consistent approach is used to clarify the problems of the boundary layer formation and stomatal interference. If the correction is taken into account, the boundary layer resistance becomes dependent also on stomatal shape and distribution on the leaf. The traditional semiempirical formula corrected by the superstomatal diffusion is applied in numerical calculations. In estimates of the water vapour mole fraction on the surface of a transpiring leaf the relative error ranges from insignificant (quiescent air, large leaf and large stomatal pores) to 20 % (low humidity, strong wind, small leaf and small elliptic pores). The boundary layer resistance can decrease by a factor of 3 when the semiaxis lengths of the stomata increase from 1 and 0.5 &mgr;m to 10 and 5 &mgr;m. The effective thickness of the superstomatal air layer is maximally several millimetres (small stomatal surface concentration and small pores). Copyright 1998 Academic Press Limited PMID:9778427

  20. Mouse forepaw lumbrical muscles are resistant to age-related declines in force production.

    PubMed

    Russell, Katelyn A; Ng, Rainer; Faulkner, John A; Claflin, Dennis R; Mendias, Christopher L

    2015-05-01

    A progressive loss of skeletal muscle mass and force generating capacity occurs with aging. Mice are commonly used in the study of aging-associated changes in muscle size and strength, with most models of aging demonstrating 15-35% reductions in muscle mass, cross-sectional area (CSA), maximum isometric force production (Po) and specific force (sPo), which is Po/CSA. The lumbrical muscle of the mouse forepaw is exceptionally small, with corresponding short diffusion distances that make it ideal for in vitro pharmacological studies and measurements of contractile properties. However, the aging-associated changes in lumbrical function have not previously been reported. To address this, we tested the hypothesis that compared to adult (12month old) mice, the forepaw lumbrical muscles of old (30month old) mice exhibit aging-related declines in size and force production similar to those observed in larger limb muscles. We found that the forepaw lumbricals were composed exclusively of fibers with type II myosin heavy chain isoforms, and that the muscles accumulated connective tissue with aging. There were no differences in the number of fibers per whole-muscle cross-section or in muscle fiber CSA. The whole muscle CSA in old mice was increased by 17%, but the total CSA of all muscle fibers in a whole-muscle cross-section was not different. No difference in Po was observed, and while sPo normalized to total muscle CSA was decreased in old mice by 22%, normalizing Po by the total muscle fiber CSA resulted in no difference in sPo. Combined, these results indicate that forepaw lumbrical muscles from 30month old mice are largely protected from the aging-associated declines in size and force production that are typically observed in larger limb muscles. PMID:25762422

  1. Coffee intake mitigated inflammation and obesity-induced insulin resistance in skeletal muscle of high-fat diet-induced obese mice.

    PubMed

    Jia, Huijuan; Aw, Wanping; Egashira, Kenji; Takahashi, Shoko; Aoyama, Shinya; Saito, Kenji; Kishimoto, Yoshimi; Kato, Hisanori

    2014-05-01

    Epidemiologic findings offer the promise that coffee or its many constituents may be useful as a dietary intervention in type 2 diabetes (T2D) prevention. We aimed to elucidate the molecular mechanisms involved in the ameliorative effects of caffeinated coffee (CC), decaffeinated coffee (DC) and unroasted caffeinated green coffee (GC) on skeletal muscle gene expression profiles and their relationships in an obesity animal model. Eight-week-old male C57BL6 mice were raised for 9 weeks ad libitum on a normal diet, a high-fat diet, or high-fat diet containing 2 % freeze-dried CC, or DC, or GC. Total RNA and protein were extracted from skeletal muscle and subjected to microarray (Mouse Genome 430 2.0, Affymetrix) and western blotting analyses, respectively. Coffee intake mitigated the insulin resistance by decreasing plasma glucose levels during an insulin tolerance test and by increasing tyrosine phosphorylation of insulin receptor substrate-1 (IRS-1), p85/IRS-1 complex and pAkt/PKB (protein kinase B). In addition, coffee intake down-regulated the anti-inflammatory genes activating transcription factor 3, FBJ osteosarcoma oncogene, heat shock protein 1A, heat shock protein 1B and synuclein, gamma and the inflammation-associated insulin signaling genes stearoyl-coenzyme A desaturase 1 and secreted phosphoprotein 1. These results provide scientific insight on the probable positive effects of coffee intake on impaired insulin signaling, inflammation and obesity, thereby providing a new perspective on the prevention of obesity and T2D. PMID:24599575

  2. Current-induced forces: a new mechanism to induce negative differential resistance and current-switching effect in molecular junctions

    NASA Astrophysics Data System (ADS)

    Gu, Lei; Fu, Hua-Hua

    2015-12-01

    Current-induced forces can excite molecules, polymers and other low-dimensional materials, which in turn leads to an effective gate voltage through Holstein interaction. Here, by taking a short asymmetric DNA junction as an example, and using the Langevin approach, we find that when suppression of charge transport by the effective gate voltage surpasses the current increase from an elevated voltage bias, the current-voltage (I-V) curves display strong negative differential resistance (NDR) and perfect current-switching characteristics. The asymmetric DNA chain differs in mechanical stability under inverse voltages and the I-V curve is asymmetric about inverse biases, which can be used to understand recent transport experiments on DNA chains, and meanwhile provides a new strategy to realize NDR in molecular junctions and other low-dimensional quantum systems.

  3. Current-induced forces: a new mechanism to induce negative differential resistance and current-switching effect in molecular junctions.

    PubMed

    Gu, Lei; Fu, Hua-Hua

    2015-12-01

    Current-induced forces can excite molecules, polymers and other low-dimensional materials, which in turn leads to an effective gate voltage through Holstein interaction. Here, by taking a short asymmetric DNA junction as an example, and using the Langevin approach, we find that when suppression of charge transport by the effective gate voltage surpasses the current increase from an elevated voltage bias, the current-voltage (I-V) curves display strong negative differential resistance (NDR) and perfect current-switching characteristics. The asymmetric DNA chain differs in mechanical stability under inverse voltages and the I-V curve is asymmetric about inverse biases, which can be used to understand recent transport experiments on DNA chains, and meanwhile provides a new strategy to realize NDR in molecular junctions and other low-dimensional quantum systems. PMID:26559504

  4. Finite element analysis of the convergence of the centers of resistance and rotation in extreme moment-to-force ratios.

    PubMed

    Geramy, Allahyar; Tanne, Kazuo; Moradi, Meisam; Golshahi, Hamid; Farajzadeh Jalali, Yasamin

    2016-06-01

    The aim of this study was to investigate how very high and very low M/F ratios affect the location of the center of rotation (CRo). A 3D model of a mesiodistal slice of the mandible was used for this purpose. The model comprised the lower right central incisor, its PDL, the spongy and cortical bone, and a bracket on the labial surface of the bracket. A couple of 1N was applied to the bracket slot to find the level of the center of resistance (Cre). In a second stage, we attempted to produce bodily movement by applying the appropriate M/F ratio. M/F ratios of ±100, 200, 400, and 800 were applied to the last tenths of a millimeter of a pre-activated loop. Higher M/F ratios with positive or negative values, at constant force, increased both incisal and apical movements. The change in the tooth inclination before and after force application matched the difference produced by the different M/F ratios. It was found that a single center of rotation can be constructed for any tooth position. However, this single point does not act as the center of rotation during the entire movement. PMID:27177875

  5. Surface potential measurement on contact resistance of amorphous-InGaZnO thin film transistors by Kelvin probe force microscopy

    NASA Astrophysics Data System (ADS)

    Han, Zhiheng; Xu, Guangwei; Wang, Wei; Lu, Congyan; Lu, Nianduan; Ji, Zhuoyu; Li, Ling; Liu, Ming

    2016-07-01

    Contact resistance plays an important role in amorphous InGaZnO (a-IGZO) thin film transistors (TFTs). In this paper, the surface potential distributions along the channel have been measured by using Kelvin probe force microscopy (KPFM) on operating a-IGZO TFTs, and sharp potential drops at the edges of source and drain were observed. The source and drain contact resistances can be extracted by dividing sharp potential drops with the corresponding drain to source current. It is found that the contact resistances could not be neglected compared with the whole channel resistances in the a-IGZO TFT, and the contact resistances decrease remarkably with increasing gate biased voltage. Our results suggest that the contact resistances can be controlled by tuning the gate biased voltage. Moreover, a transition from gradual channel approximation to space charge region was observed through the surface potential map directly when TFT operating from linear regime to saturation regime.

  6. Evaluation of wheelchair resistive forces during straight and turning trajectories across different wheelchair configurations using free-wheeling coast-down test.

    PubMed

    Lin, Jui-Te; Huang, Morris; Sprigle, Stephen

    2015-01-01

    The purpose of this study was to develop a simple approach to evaluate resistive frictional forces acting on manual wheelchairs (MWCs) during straight and turning maneuvers. Using a dummy-occupied MWC, decelerations were measured via axle-mounted encoders during a coast-down protocol that included straight trajectories and fixed-wheel turns. Eight coast-down trials were conducted to test repeatability and repeated on separate days to evaluate reliability. Without changing the inertia of the MWC system, three tire inflations were chosen to evaluate the sensitivity in discerning deceleration differences using effect sizes. The technique was also deployed to investigate the effect of different MWC masses and weight distributions on resistive forces. Results showed that the proposed coast-down technique had good repeatability and reliability in measuring decelerations and had good sensitivity in discerning differences in tire inflation, especially during turning. The results also indicated that increased loading on drive wheels reduced resistive losses in straight trajectories while increasing resistive losses during turning. During turning trajectories, the presence of tire scrub contributes significantly to the amount of resistive force. Overall, this new coast-down technique demonstrates satisfactory repeatability and sensitivity for detecting deceleration changes during straight and turning trajectories, indicating that it can be used to evaluate resistive loss of different MWC configurations and maneuvers. PMID:26745011

  7. Acaricide resistance and strategies to mitigate economic impact of the southern cattle fever tick (Rhipicephalus microplus) on livestock production systems in the Americas

    Technology Transfer Automated Retrieval System (TEKTRAN)

    BACKGROUND: The southern cattle fever tick (SCFT), Rhipicephalus microplus, is considered the most economically important external parasite of livestock worldwide. SCFT populations resistant to acaricides complicate efforts to enhance the productivity of livestock. Here, acaricide resistance is summ...

  8. Disruption Mitigation Technology Concepts and Implications for ITER

    SciTech Connect

    Baylor, Larry R; Jernigan, Thomas C; Combs, Stephen Kirk; Meitner, S. J.; Caughman, John B; Commaux, Nicolas JC; Rasmussen, David A; Parks, P. B.; Glugla, M.; Maruyama, So; Pearce, R.J.H.; Lehnen, M.

    2010-01-01

    Disruptions on ITER present challenges to handle the intense heat flux, the large forces from halo currents, and the potential first wall damage from energetic runaway electrons. Injecting large quantities of material into the plasma during the disruption can reduce the plasma energy and increase its resistivity to mitigate these effects. Assessments of the amount of various mixtures and quantities of material required have been made to provide collision mitigation of runaway electron conversion [1], which is the most difficult challenge. The quantities of material required (~0.5 MPa-m3 for deuterium or helium gas) are large enough to have implications on the design and operation of the vacuum system and tokamak exhaust processing system.

  9. Disruption Mitigation Technology Concepts and Implications for ITER

    SciTech Connect

    Baylor, Larry R; Jernigan, Thomas C; Combs, Stephen Kirk; Meitner, Steven J; Rasmussen, David A; Parks, P. B.; Glugla, M.; Maruyama, So; Pearce, R.J.H.; Lehnen, M.

    2009-01-01

    Disruptions on ITER present challenges to handle the intense heat flux, the large forces from halo currents, and the potential first wall damage from energetic runaway electrons. Injecting large quantities of material into the plasma during the disruption can reduce the plasma energy and increase its resistivity to mitigate these effects. Assessments of the amount of various mixtures and quantities of material required have been made to provide collision mitigation of runaway electron conversion [1] which is the most difficult challenge. The quantities of material required (~0.5 MPa-m3 for deuterium or helium gas) are large enough to have implications on the design and operation of the vacuum system and tokamak exhaust processing system.

  10. Contributions of force and velocity to improved power with progressive resistance training in young and older adults.

    PubMed

    Petrella, John K; Kim, Jeong-Su; Tuggle, S Craig; Bamman, Marcas M

    2007-03-01

    We investigated the effects of age on changes in the force and velocity components of knee extension (KE) power during 16 weeks of traditional progressive resistance training (PRT). Thirty-one young (27 +/- 1 years, 16 men, 15 women) and 30 older (64 +/- 1 years, 14 men, 16 women) adults trained by KE, leg press, and squat 3 days/week. PRT consisted of three sets with an appropriate load for 8-12 repetitions to fatigue. Testing occurred at baseline, 8, and 16 weeks. Thigh lean mass (TLM) was measured by DEXA. KE load-power and load-velocity curves were generated from peak concentric contractions against loads equivalent to 20, 30, 40, 50, and 60% maximum voluntary isometric contraction (MVC) force. Quadriceps neural activation relative to maximum was assessed during a sit-to-stand task. Participants increased KE 1RM (P < 0.05) by 8 weeks with young adults also increasing strength from 8 to 16 weeks. Adjusting for TLM, all groups increased KE specific strength (P < 0.05). MVC improved by 8 weeks in older adults and by 16 weeks in young subjects (P < 0.05). Neural activation requirements during standing and sitting declined in older adults by 8 weeks (P < 0.05). The KE load-power curve improved for all groups (P < 0.05) by 8 weeks with only young adults improving from 8 to 16 weeks. Peak concentric velocity increased only in older adults (P < 0.05). Training improvements in power resulted primarily from increases in strength both early and late for young adults while older adults realized early improvements in both strength and peak concentric velocity. PMID:17165058

  11. Returning home: forced conscription, reintegration, and mental health status of former abductees of the Lord's Resistance Army in northern Uganda

    PubMed Central

    Pham, Phuong N; Vinck, Patrick; Stover, Eric

    2009-01-01

    Background Since the late 1980s, the Lord's Resistance Army (LRA), a spiritualist rebel group in northern Uganda, has killed and mutilated thousands of civilians and abducted an estimated 52,000 to 75,000 people to serve as soldiers, porters, and sex slaves for its commanders. This study examines the types of violence to which former abductees have been exposed and the extent to which these acts have affected their psychological well-being. Methods This is a cross-sectional study of 2,875 individuals selected through a multi-stage stratified cluster sampling design conducted in 8 districts of northern Uganda. Multivariate logistic regressions were performed with symptoms for Post-traumatic Stress Disorder (PTSD) and depression as the main outcome measures. Results One-third of the respondents (33%) self-reported having experienced abduction (49% among the Acholi, the largest tribal group in northern Uganda). Over half (56%) of all the respondents and over two-thirds of those who experienced abduction met the criteria for symptoms of post-traumatic stress disorder (PTSD). Multivariate analysis shows that several factors increased the risk of former LRA abductees developing symptoms of PTSD. These factors included gender (females were more susceptible than males), being a member of the Acholi ethnic group, participating in or witnessing a cumulative number of traumatic events, and encountering difficulties re-integrating into communities after abduction. Factors associated with increased risk of meeting criteria for symptoms of depression included older age of males at the time of abduction, lower score on social relationship scale, high incidence of general traumatic event exposure, high incidence of forced acts of violence, and problems reintegrating into communities after abduction. Conclusion Abduction and forced conscription of civilians has affected the psychological well-being of a significant number of northern Ugandans. The sources of psychological trauma

  12. How mothers mediate the social integration of their children conceived of forced marriage within the Lord's Resistance Army.

    PubMed

    Shanahan, Fiona; Veale, Angela

    2016-01-01

    This article aims to understand how formerly abducted young mothers mediate the social integration of their children conceived of forced marriage and sexual violence within the Lord's Resistance Army (LRA) in northern Uganda. Interviews and photographic methods were used in six Internally Displaced Persons Camps in northern Uganda. This article draws on data derived from ten mothers of thirteen children who were conceived in the LRA, five boys and eight girls. The analytic approach used was Interpretive Phenomenological Analysis (Smith & Osborn, 2008). The analysis identified turning points of sites of action where young formerly abducted mothers used diverse strategies to support the reintegration of their children born or conceived within the LRA. Six key turning points are identified, these are (a) participating in rituals and ceremonies, (b) naming, (c) adapting to changing family structures, (d) responding to discrimination against boys (e) managing disclosure and (f) sharing positive memories and identities. Formerly abducted young mothers mediate the social integration of their children by engaging in strategies to support and foster their wellbeing and social relationships. However, the contexts in which they are operating are highly constrained and the relational identities of children born in the LRA are fluid and potentially insecure within communities of return. Implications for policy and programming are discussed. PMID:26671833

  13. Subsurface evaluation of the west parking lot and landfill 3 areas of Air Force Plant 4, Fort Worth, Texas, using two-dimensional direct-current resistivity profiling

    USGS Publications Warehouse

    Braun, Christopher L.; Jones, Sonya A.

    2002-01-01

    During September 1999, the U.S. Geological Survey made 10 two-dimensional direct-current resistivity profile surveys in the west parking lot and landfill 3 areas of Air Force Plant 4, Fort Worth, Texas, to identify subsurface areas of anomalously high or low resistivity that could indicate potential contamination, contaminant pathways, or anthropogenic structures. Six of the 10 surveys (transects) were in the west parking lot. Each of the inverted sections of these transects had anomalously high resistivities in the terrace alluvium/fill (the surficial subsurface layer) that probably were caused by highly resistive fill material. In addition, each of these transects had anomalously low resistivities in the Walnut Formation (a bedrock layer immediately beneath the alluvium/fill) that could have been caused by saturation of fractures within the Walnut Formation. A high-resistivity anomaly in the central part of the study area probably is associated with pea gravel fill used in construction of a French drain. Another high resistivity anomaly in the west parking lot, slightly southeast of the French drain, could be caused by dense nonaqueous-phase liquid in the Walnut Formation. The inverted sections of the four transects in the landfill 3 area tended to have slightly higher resistivities in both the alluvium/fill and the Walnut Formation than the transects in the west parking lot. The higher resistivities in the alluvium/fill could have been caused by drier conditions in grassy areas relative to conditions in the west parking lot. Higher resistivities in parts of the Walnut Formation also could be a function of drier conditions or variations in the lithology of the Walnut Formation. In addition to the 10 vertical sections, four horizontal sections at 2-meteraltitude intervals show generally increasing resistivity with decreasing altitude that most likely results from the increased influence of the Walnut Formation, which has a higher resistivity than the terrace

  14. In situ dissolution analysis of half-pitch line and space patterns at various resist platforms using high speed atomic force microscopy

    NASA Astrophysics Data System (ADS)

    Santillan, Julius Joseph; Itani, Toshiro

    2013-03-01

    Preliminary results of in situ analyses of dissolution of resist patterns of half-pitch (hp) lines and spaces (L/S) using high-speed atomic force microscopy are discussed. Initial experiments were conducted on an EUV-exposed 32 nm hp L/S pattern using a standard concentration (0.26 N) of tetramethylammonium hydroxide (TMAH) developer solution. This was done using a carbon nanofiber-based cantilever tip and after various tool enhancements and optimizations. Difference in the dissolution characteristics of various resist polymers such as polyhydroxystyrene (PHS)-based and hybrid (PHS-methacryl) resists was observed. These results are in agreement with the previously obtained results of measurements performed with 32 nm isolated line patterns on resist films developed with diluted developer solutions (1/20 of 0.26 N TMAH), where the PHS-based resist showed a uniformly dissolved, grain-like dissolution characteristic, while the hybrid resist exhibited resist swelling of the exposed resist film.

  15. Novel strategy to mitigate cathode catalyst degradation during air/air startup cycling via the atmospheric resistive switching mechanism of a hydrogen anode with a platinum catalyst supported on tantalum-doped titanium dioxide

    NASA Astrophysics Data System (ADS)

    Shintani, Haruhiko; Kojima, Yuya; Kakinuma, Katsuyoshi; Watanabe, Masahiro; Uchida, Makoto

    2015-10-01

    We propose a new strategy for alleviating the reverse current phenomenon using a unique "atmospheric resistive switching mechanism" (ARSM) of a metal oxide semiconductor support, such that the electrical resistivity changes depending on the gas atmosphere. The membrane-electrode assembly (MEA) using Ta-doped TiO2-supported platinum (Pt/Ta-TiO2) as the anode catalyst showed approximately one order of magnitude greater resistance in air than in hydrogen. The overpotential of the hydrogen oxidation reaction was negligible up to at least 1.5 A cm-2. The losses of electrochemically active surface area and carbon corrosion of the cathode catalyst during air/air startup cycling were significantly suppressed by the use of the Pt/Ta-TiO2 anode. The decrease in the degradation is attributed to a reduction of the reverse current due to a low oxygen reduction reaction rate at the anode, which showed high resistivity in air. These results demonstrate the effectiveness of the ARSM in mitigating cathode catalyst degradation during air/air startup cycling.

  16. Line-pattern collapse mitigation status for EUV at 32nm HP and below

    NASA Astrophysics Data System (ADS)

    Carcasi, Michael; Bassett, Derek; Printz, Wallace; Kawakami, Shinichiro; Miyata, Yuichiro

    2012-03-01

    Line pattern collapse (LPC) becomes a critical concern as integrated circuit fabrication continues to advance towards the 22 nm node and below. Tokyo Electron Limited (TEL) has been investigating LPC mitigation methods for many years [1]. These mitigation methods include surfactant rinses to help reduce surface tension and Laplace pressures forces that accompany traditional DIW rinses. However, the ability to explore LPC mitigation techniques at EUV dimensions is experimentally limited by the cost and availability of EUV exposures. With this in mind, TEL has adopted a combined experimental and simulation approach to further explore LPC mitigation methods. Several analytical models have been proposed [2, 3, 4] for a LPC simulation approach. However, the analytical models based on Euler beam theory are limited in the complexity of profile and material assumptions. Euler beam based models are also now questionable because they are outside the beam theory's intended aspect ratio regime [5]. The authors explore the use of finite element models in addition to Euler beam theory based models to understand resist collapse under typical EUV patterning conditions. The versatility of current finite element techniques allows for exploration of resist material property effects, profile and geometry effects, surface versus bulk modulus effects, and rinse and surfactant rinse effects. This paper will discuss pattern-collapse trends and offers critical learning from this simulation approach combined with experimental results from an EUV exposure system and TEL CLEAN TRACK ACTTM 12 platform, utilizing state of the art collapse mitigation methods.

  17. Differences in Supraspinal and Spinal Excitability during Various Force Outputs of the Biceps Brachii in Chronic- and Non-Resistance Trained Individuals

    PubMed Central

    Pearcey, Gregory E. P.; Power, Kevin E.; Button, Duane C.

    2014-01-01

    Motor evoked potentials (MEP) and cervicomedullary evoked potentials (CMEP) may help determine the corticospinal adaptations underlying chronic resistance training-induced increases in voluntary force production. The purpose of the study was to determine the effect of chronic resistance training on corticospinal excitability (CE) of the biceps brachii during elbow flexion contractions at various intensities and the CNS site (i.e. supraspinal or spinal) predominantly responsible for any training-induced differences in CE. Fifteen male subjects were divided into two groups: 1) chronic resistance-trained (RT), (n = 8) and 2) non-RT, (n = 7). Each group performed four sets of ∼5 s elbow flexion contractions of the dominant arm at 10 target forces (from 10%–100% MVC). During each contraction, subjects received 1) transcranial magnetic stimulation, 2) transmastoid electrical stimulation and 3) brachial plexus electrical stimulation, to determine MEP, CMEP and compound muscle action potential (Mmax) amplitudes, respectively, of the biceps brachii. All MEP and CMEP amplitudes were normalized to Mmax. MEP amplitudes were similar in both groups up to 50% MVC, however, beyond 50% MVC, MEP amplitudes were lower in the chronic RT group (p<0.05). CMEP amplitudes recorded from 10–100% MVC were similar for both groups. The ratio of MEP amplitude/absolute force and CMEP amplitude/absolute force were reduced (p<0.012) at all contraction intensities from 10–100% MVC in the chronic-RT compared to the non-RT group. In conclusion, chronic resistance training alters supraspinal and spinal excitability. However, adaptations in the spinal cord (i.e. motoneurone) seem to have a greater influence on the altered CE. PMID:24875495

  18. Effect of electrode force condition on nugget diameter and residual stress in resistance spot welded high-strength steel sheets

    NASA Astrophysics Data System (ADS)

    Iyota, M.; Mikami, Y.; Hashimoto, T.; Taniguchi, K.; Ikeda, R.; Mochizuki, M.

    2012-08-01

    This study examines the effect of the electrode force condition on the nugget diameter and residual stress in spot welded high-strength steel sheets. Numerical simulations of spot welding were performed to examine the nugget diameter and residual stress. The results indicate that adjusting the force profile changes the current density and stress state at the spot welds. Therefore, choosing an appropriate force profile extends the nugget diameter and reduces the residual stress.

  19. Relationship between interfacial forces measured by colloid-probe atomic force microscopy and protein resistance of poly(ethylene glycol)-grafted poly(L-lysine) adlayers on niobia surfaces.

    PubMed

    Pasche, Stéphanie; Textor, Marcus; Meagher, Laurence; Spencer, Nicholas D; Griesser, Hans J

    2005-07-01

    Adsorbed layers of "comb-type" copolymers consisting of PEG chains grafted onto a poly(l-lysine) (PLL) backbone on niobium oxide substrates were studied by colloid-probe AFM in order to characterize the interfacial forces associated with coatings of varying architectures (PEG/PLL ratios and PEG chain lengths) and their relevance to protein resistance. The steric and electrostatic forces measured varied substantially with the architecture of the PLL-g-PEG copolymers. Varying the ionic strength of the buffer solutions enabled discrimination between electrostatic and steric-entropic contributions to the net interfacial force. For high PEG grafting densities the steric component was most prominent, but at low ionic strengths and high grafting densities, a repulsive electrostatic surface force was also observed; its origin was assigned to the niobia charges beneath the copolymer, as insufficient protonated amine groups in the PLL backbone were available for compensation of the oxide surface charges. For lower grafting densities and lower ionic strengths there was a substantial attractive electrostatic contribution arising from interaction of the electrical double layer arising from the protonated amine groups, with that of the silica probe surface (as under low ionic strength conditions, the electrical double layer was thicker than the PEG layer). For these PLL-g-PEG coatings the net interfacial force can thus be a markedly varying superposition of electrostatic and steric-entropic contributions, depending on various factors. The force curves correlate with protein adsorption data, demonstrating the utility of AFM colloid-probe force measurements for quantitative analysis of surface forces and how they determine interfacial interactions with proteins. Such characterization of the net interfacial forces is essential to elucidate the multiple types of interfacial forces relevant to the interactions between PLL-g-PEG coatings and proteins and to advance interpretation of

  20. Electrostatic-Force-Assisted Dispensing Printing to Construct High-Aspect-Ratio of 0.79 Electrodes on a Textured Surface with Improved Adhesion and Contact Resistivity

    PubMed Central

    Shin, Dong-Youn; Yoo, Sung-Soo; Song, Hee-eun; Tak, Hyowon; Byun, Doyoung

    2015-01-01

    As a novel route to construct fine and abnormally high-aspect-ratio electrodes with excellent adhesion and reduced contact resistivity on a textured surface, an electrostatic-force-assisted dispensing printing technique is reported and compared with conventional dispensing and electrohydrodynamic jet printing techniques. The electrostatic force applied between a silver paste and the textured surface of a crystalline silicon solar cell wafer significantly improves the physical adhesion of the electrodes, whereas those fabricated using a conventional dispensing printing technique peel off with a silver paste containing 2 wt% of a fluorosurfactant. Moreover, the contact resistivity and dimensionless deviation of total resistance are significantly reduced from 2.19 ± 1.53 mΩ·cm2 to 0.98 ± 0.92 mΩ·cm2 and from 0.10 to 0.03, respectively. By utilizing electrodes with an abnormally high-aspect-ratio of 0.79 (the measured thickness and width are 30.4 μm and 38.3 μm, respectively), the cell efficiency is 17.2% on a polycrystalline silicon solar cell with an emitter sheet resistance of 60 Ω/sq. This cell efficiency is considerably higher than previously reported values obtained using a conventional electrohydrodynamic jet printing technique, by +0.48–3.5%p. PMID:26576857

  1. Resistive and reactive changes to the impedance of intracortical microelectrodes can be mitigated with polyethylene glycol under acute in vitro and in vivo settings

    PubMed Central

    Sommakia, Salah; Gaire, Janak; Rickus, Jenna L.; Otto, Kevin J.

    2014-01-01

    The reactive response of brain tissue to implantable intracortical microelectrodes is thought to negatively affect their recordable signal quality and impedance, resulting in unreliable longitudinal performance. The relationship between the progression of the reactive tissue into a glial scar and the decline in device performance is unclear. We show that exposure to a model protein solution in vitro and acute implantation result in both resistive and capacitive changes to electrode impedance, rather than purely resistive changes. We also show that applying 4000 MW polyethylene glycol (PEG) prevents impedance increases in vitro, and reduces the percent change in impedance in vivo following implantation. Our results highlight the importance of considering the contributions of non-cellular components to the decline in neural microelectrode performance, and present a proof of concept for using a simple dip-coated PEG film to modulate changes in microelectrode impedance. PMID:25136315

  2. An extract of Urtica dioica L. mitigates obesity induced insulin resistance in mice skeletal muscle via protein phosphatase 2A (PP2A).

    PubMed

    Obanda, Diana N; Ribnicky, David; Yu, Yongmei; Stephens, Jacqueline; Cefalu, William T

    2016-01-01

    The leaf extract of Urtica dioica L. (UT) has been reported to improve glucose homeostasis in vivo, but definitive studies on efficacy and mechanism of action are lacking. We investigated the effects of UT on obesity- induced insulin resistance in skeletal muscle. Male C57BL/6J mice were divided into three groups: low-fat diet (LFD), high-fat diet (HFD) and HFD supplemented with UT. Body weight, body composition, plasma glucose and plasma insulin were monitored. Skeletal muscle (gastrocnemius) was analyzed for insulin sensitivity, ceramide accumulation and the post translational modification and activity of protein phosphatase 2A (PP2A). PP2A is activated by ceramides and dephosphorylates Akt. C2C12 myotubes exposed to excess free fatty acids with or without UT were also evaluated for insulin signaling and modulation of PP2A. The HFD induced insulin resistance, increased fasting plasma glucose, enhanced ceramide accumulation and PP2A activity in skeletal muscle. Supplementation with UT improved plasma glucose homeostasis and enhanced skeletal muscle insulin sensitivity without affecting body weight and body composition. In myotubes, UT attenuated the ability of FFAs to induce insulin resistance and PP2A hyperactivity without affecting ceramide accumulation and PP2A expression. UT decreased PP2A activity through posttranslational modification that was accompanied by a reduction in Akt dephosphorylation. PMID:26916435

  3. An extract of Urtica dioica L. mitigates obesity induced insulin resistance in mice skeletal muscle via protein phosphatase 2A (PP2A)

    PubMed Central

    Obanda, Diana N.; Ribnicky, David; Yu, Yongmei; Stephens, Jacqueline; Cefalu, William T.

    2016-01-01

    The leaf extract of Urtica dioica L. (UT) has been reported to improve glucose homeostasis in vivo, but definitive studies on efficacy and mechanism of action are lacking. We investigated the effects of UT on obesity- induced insulin resistance in skeletal muscle. Male C57BL/6J mice were divided into three groups: low-fat diet (LFD), high-fat diet (HFD) and HFD supplemented with UT. Body weight, body composition, plasma glucose and plasma insulin were monitored. Skeletal muscle (gastrocnemius) was analyzed for insulin sensitivity, ceramide accumulation and the post translational modification and activity of protein phosphatase 2A (PP2A). PP2A is activated by ceramides and dephosphorylates Akt. C2C12 myotubes exposed to excess free fatty acids with or without UT were also evaluated for insulin signaling and modulation of PP2A. The HFD induced insulin resistance, increased fasting plasma glucose, enhanced ceramide accumulation and PP2A activity in skeletal muscle. Supplementation with UT improved plasma glucose homeostasis and enhanced skeletal muscle insulin sensitivity without affecting body weight and body composition. In myotubes, UT attenuated the ability of FFAs to induce insulin resistance and PP2A hyperactivity without affecting ceramide accumulation and PP2A expression. UT decreased PP2A activity through posttranslational modification that was accompanied by a reduction in Akt dephosphorylation. PMID:26916435

  4. Precise control of surface electrostatic forces on polymer brush layers with opposite charges for resistance to protein adsorption.

    PubMed

    Sakata, Sho; Inoue, Yuuki; Ishihara, Kazuhiko

    2016-10-01

    Various molecular interaction forces are generated during protein adsorption process on material surfaces. Thus, it is necessary to control them to suppress protein adsorption and the subsequent cell and tissue responses. A series of binary copolymer brush layers were prepared via surface-initiated atom transfer radical polymerization, by mixing the cationic monomer unit and anionic monomer unit randomly in various ratios. Surface characterization revealed that the constructed copolymer brush layers exhibited an uniform super-hydrophilic nature and different surface potentials. The strength of the electrostatic interaction forces operating on these mixed-charge copolymer brush surfaces was evaluated quantitatively using force-versus-distance (f-d) curve measurements by atomic force microscopy (AFM) and probes modified by negatively charged carboxyl groups or positively charged amino groups. The electrostatic interaction forces were determined based on the charge ratios of the copolymer brush layers. Notably, the surface containing equivalent cationic/anionic monomer units hardly interacted with both the charged groups. Furthermore, the protein adsorption force and the protein adsorption mass on these surfaces were examined by AFM f-d curve measurement and surface plasmon resonance measurement, respectively. To clarify the influence of the electrostatic interaction on the protein adsorption behavior on the surface, three kinds of proteins having negative, positive, and relatively neutral net charges under physiological conditions were used in this study. We quantitatively demonstrated that the amount of adsorbed proteins on the surfaces would have a strong correlation with the strength of surface-protein interaction forces, and that the strength of surface-protein interaction forces would be determined from the combination between the properties of the electrostatic interaction forces on the surfaces and the charge properties of the proteins. Especially, the

  5. High-level iron mitigates fusaricidin-induced membrane damage and reduces membrane fluidity leading to enhanced drug resistance in Bacillus subtilis.

    PubMed

    Yu, Wen-Bang; Ye, Bang-Ce

    2016-05-01

    Fusaricidins are a class of cyclic lipopeptide antibiotics that have strong antifungal activities against plant pathogenic fungi and excellent bactericidal activities against Gram-positive bacteria. The mechanism through which fusaricidin exerts its action is not yet entirely clear. To investigate the mode of action of fusaricidin, we determined the physiological and transcriptional responses of Bacillus subtilis to fusaricidin treatment by using a systems-level approach. Our data show that fusaricidin rapidly induced the expression of σ(W) regulon and caused membrane damage in B. subtilis. We further demonstrated that ferric ions play multiple roles in the action of fusaricidin on B. subtilis. Iron deprivation blocked the formation of hydroxyl radical in the cells and significantly inhibited the bactericidal activity of fusaricidin. Conversely, high levels of iron (>2 mM) repressed the expression of BkdR regulon, resulting in a smaller cellular pool of branched-chain precursors for iso- and anteiso-branched fatty acids, which in turn led to a decrease in the proportion of branched-chain fatty acids in the membrane of B. subtilis. This change in membrane composition reduced its bilayer fluidity and increased its resistance to antimicrobial agents. In conclusion, our experiments uncovered some novel interactions and a synergism between cellular iron levels and drug resistance in Gram-positive bacteria. PMID:26467177

  6. The Effect of Inter-Implant Distance on Retention and Resistance to Dislodging Forces for Mandibular Implant-Tissue-Supported Overdentures

    PubMed Central

    Tabatabaian, Farhad; Saboury, Abolfazl; Sobhani, Zahra Sadat; Petropoulos, Vicki C

    2014-01-01

    Objectives: The effect of inter-implant distance on retention and resistance of implant-tissue-supported overdentures is lacking in the literature. An in vitro study was performed to evaluate this effect for mandibular implant-tissue-supported overdentures retained by two ball attachments. Materials and Methods: An acrylic cast of an edentulous mandible was fabricated. Three pairs of implants were symmetrically placed at both sides of the midline. The inter-implant distance was 10, 25, and 35 millimeters in positions A, B and C, respectively. A framework simulating the overdenture was fabricated on the cast. Six attachment housings were placed within the overdenture. For each sample, two ball abutments were screwed onto the implant pairs and two pink nylon inserts were seated in their respective attachment housings. The samples were tested in three groups of 15 (A, B, and C). The testing machine applied tensile dislodging forces and peak loads were measured in three directions: vertical, oblique, and anterior-posterior. A one-way ANOVA followed by Tukey’s HSD was used to determine groups that were significantly different. Tests were carried out at 0.05 level of significance. Results: Peak loads for the anterior-posteriorly directed dislodging forces were significantly the highest for group C (P<0.05); 21.25 N±3.05 N, while there were no statistically significant differences among groups with vertically and obliquely directed forces (P>0.05). Conclusion: Inter-implant distance did not affect the vertical retention and oblique resistance of mandibular implant-tissue-supported overdentures; however, it affected anterior-posterior resistance. PMID:25628676

  7. [Improving of muscle mass and force in rehabilitation of heart-lung patients. Aerobic interval training, resistance-exercises, excentric exercises, vibration].

    PubMed

    Apor, Péter; Tihanyi, József; Borka, Péter

    2005-09-18

    Improvement of muscle mass and force which got depleted by inactivity or pathological processes is one of the aims and also a prerequisite of a rehabilitative intervention. Metabolically active larger and stronger muscles diminish the cardiovascular risk, permit the aerobic preventive and rehabilitative activities and enables a higher quality of life. Interval forms of aerobic exercise improves also the muscles. The resistance training plays an important part in rehabilitation. Beside the traditional dynamic strength training with weights, gym machines, body weight etc. the excentric type of muscle activity potentiates higher muscle load with lesser energy consumption, therefore it is suitable in the case of smaller performance ability. Vibration of the whole body or parts of it by machines improves the co-activity of the motor units and results in force development with small metabolic involvement. PMID:16238250

  8. Instability of Contact Resistance in MEMS and NEMS DC Switches under Low Force: the Role of Alien Films on the Contact Surface

    PubMed Central

    Qiu, Haodong; Wang, Hong; Ke, Feixiang

    2013-01-01

    The metal contact is one of the most crucial parts in ohmic-contact microelectromechanical (MEMS) switches, as it determines the device performance and reliability. It has been observed that there is contact instability when the contact force is below a threshold value (minimum contact force). However, there has been very limited knowledge so far about the unstable electrical contact behavior under low contact force. In this work, the instability of Au-Au micro/nano-contact behavior during the initial stage of contact formation is comprehensively investigated for the first time. It has been found that the alien film on the contact surface plays a critical role in determining the contact behavior at the initial contact stage under low contact force. A strong correlation between contact resistance fluctuation at the initial contact stage and the presence of a hydrocarbon alien film on the contact surface is revealed. The enhancement of contact instability due to the alien film can be explained within a framework of trap-assisted tunneling.

  9. Gas powered fluid gun with recoil mitigation

    DOEpatents

    Grubelich, Mark C.; Yonas, Gerold

    2016-03-01

    A gas powered fluid gun for propelling a stream or slug of a fluid at high velocity toward a target. Recoil mitigation is provided that reduces or eliminates the associated recoil forces, with minimal or no backwash. By launching a quantity of water in the opposite direction, net momentum forces are reduced or eliminated. Examples of recoil mitigation devices include a cone for making a conical fluid sheet, a device forming multiple impinging streams of fluid, a cavitating venturi, one or more spinning vanes, or an annular tangential entry/exit.

  10. Gas powered fluid gun with recoil mitigation

    DOEpatents

    Grubelich, Mark C; Yonas, Gerold

    2013-11-12

    A gas powered fluid gun for propelling a stream or slug of a fluid at high velocity toward a target. Recoil mitigation is provided that reduces or eliminates the associated recoil forces, with minimal or no backwash. By launching a quantity of water in the opposite direction, net momentum forces are reduced or eliminated. Examples of recoil mitigation devices include a cone for making a conical fluid sheet, a device forming multiple impinging streams of fluid, a cavitating venturi, one or more spinning vanes, or an annular tangential entry/exit.

  11. Efficacy of a trunk orthosis with joints providing resistive force on low-back load in elderly persons during static standing

    PubMed Central

    Katsuhira, Junji; Matsudaira, Ko; Yasui, Tadashi; Iijima, Shinno; Ito, Akihiro

    2015-01-01

    Purpose Postural alignment of elderly people becomes poor due to aging, possibly leading to low-back pain and spinal deformity. Although there are several interventions for treating these conditions, no previous study has reported the effectiveness of a spinal orthosis or lumbosacral orthosis (LSO) in healthy elderly people without specific spinal deformity. We therefore developed a trunk orthosis to decrease low-back muscle activity while training good postural alignment through resistive force provided by joints with springs (here, called the ORF, which stands for orthosis with joints providing resistive force) as a preventive method against abnormal posture and low-back pain in healthy elderly persons. Patients and methods Fifteen community-dwelling elderly men participated in this study. Participants stood freely for 10 seconds in a laboratory setting under three conditions: without an orthosis, with the ORF, and with an LSO. The Damen corset LSO was selected as it is frequently prescribed for patients with low-back pain. Postural alignment during static standing was recorded using a three-dimensional motion capture system employing infrared cameras. Two force plates were used to record center of pressure. Electromyograms were obtained for bilateral erector spinae (ES), left internal abdominal oblique, and right gluteus medius muscles. Results Pelvis forward tilt angle tended to increase while wearing the ORF and decrease while wearing the LSO, but these results were not significant compared to no orthosis. Thorax extension angle and thorax angle on pelvis coordinate system significantly increased while wearing the ORF compared to the other two conditions. ES activity significantly decreased while wearing the ORF compared to the other two conditions. Internal oblique activity was significantly smaller while wearing the LSO than with no orthosis. Center of pressure did not significantly differ among the conditions. Conclusion The ORF significantly improved trunk

  12. Surface potential and resistance measurements for detecting wear of chemically-bonded and unbonded molecularly-thick perfluoropolyether lubricant films using atomic force microscopy.

    PubMed

    Palacio, Manuel; Bhushan, Bharat

    2007-11-01

    The wear of perfluoropolyether (PFPE) lubricants applied on Si(100) and an Au film on Si(100) substrate at ultralow loads was investigated by using atomic force microscopy (AFM)-based surface potential and resistance measurements. Surface potential data is used in detecting lubricant removal and the initiation of wear on the silicon substrate. The surface potential change is attributed to the change in the work function of the silicon after wear, and electrostatic charge build-up of debris in the lubricant. It was found that coatings that are partially bonded, i.e., containing a mobile lubricant fraction, were better able to protect the silicon substrate from wear compared to the fully bonded coating. This enhanced protection is attributed to a lubricant replenishment mechanism. However, an untreated lubricant coating exhibited considerable wear as it contains a smaller amount of lubricant bonded to the substrate relative to the partially bonded and fully bonded coatings. A sample subjected to shear is shown to have improved wear resistance, and this enhancement is attributed to chain reorientation and alignment of the lubricant molecules. The detection of wear of PFPE lubricants on Au by an AFM-based resistance measurement method is demonstrated for the first time. This technique provides complementary information to surface potential data in detecting substrate exposure after wear and is a promising method for studying the wear of conducting films. PMID:17631305

  13. Space Debris & its Mitigation

    NASA Astrophysics Data System (ADS)

    Kaushal, Sourabh; Arora, Nishant

    2012-07-01

    Space debris has become a growing concern in recent years, since collisions at orbital velocities can be highly damaging to functioning satellites and can also produce even more space debris in the process. Some spacecraft, like the International Space Station, are now armored to deal with this hazard but armor and mitigation measures can be prohibitively costly when trying to protect satellites or human spaceflight vehicles like the shuttle. This paper describes the current orbital debris environment, outline its main sources, and identify mitigation measures to reduce orbital debris growth by controlling these sources. We studied the literature on the topic Space Debris. We have proposed some methods to solve this problem of space debris. We have also highlighted the shortcomings of already proposed methods by space experts and we have proposed some modification in those methods. Some of them can be very effective in the process of mitigation of space debris, but some of them need some modification. Recently proposed methods by space experts are maneuver, shielding of space elevator with the foil, vaporizing or redirecting of space debris back to earth with the help of laser, use of aerogel as a protective layer, construction of large junkyards around international space station, use of electrodynamics tether & the latest method proposed is the use of nano satellites in the clearing of the space debris. Limitations of the already proposed methods are as follows: - Maneuvering can't be the final solution to our problem as it is the act of self-defence. - Shielding can't be done on the parts like solar panels and optical devices. - Vaporizing or redirecting of space debris can affect the human life on earth if it is not done in proper manner. - Aerogel has a threshold limit up to which it can bear (resist) the impact of collision. - Large junkyards can be effective only for large sized debris. In this paper we propose: A. The Use of Nano Tubes by creating a mesh

  14. Fatigue resistance, debonding force, and failure type of fiber-reinforced composite, polyethylene ribbon-reinforced, and braided stainless steel wire lingual retainers in vitro

    PubMed Central

    Foek, Dave Lie Sam; Özcan, Mutlu

    2013-01-01

    Objective To analyze the fatigue resistance, debonding force, and failure type of fiber-reinforced composite, polyethylene ribbon-reinforced, and braided stainless steel wire lingual retainers in vitro. Methods Roots of human mandibular central incisors were covered with silicone, mimicking the periodontal ligament, and embedded in polymethylmethacrylate. The specimens (N = 50), with two teeth each, were randomly divided into five groups (n = 10/group) according to the retainer materials: (1) Interlig (E-glass), (2) everStick Ortho (E-glass), (3) DentaPreg Splint (S2-glass), (4) Ribbond (polyethylene), and (5) Quad Cat wire (stainless steel). After the recommended adhesive procedures, the retainers were bonded to the teeth by using flowable composite resin (Tetric Flow). The teeth were subjected to 10,00,000 cyclic loads (8 Hz, 3 - 100 N, 45° angle, under 37 ± 3℃ water) at their incisoproximal contact, and debonding forces were measured with a universal testing machine (1 mm/min crosshead speed). Failure sites were examined under a stereomicroscope (×40 magnification). Data were analyzed by one-way analysis of variance. Results All the specimens survived the cyclic loading. Their mean debonding forces were not significantly different (p > 0.05). The DentaPreg Splint group (80%) showed the highest incidence of complete adhesive debonding, followed by the Interlig group (60%). The everStick Ortho group (80%) presented predominantly partial adhesive debonding. The Quad Cat wire group (50%) presented overlying composite detachment. Conclusions Cyclic loading did not cause debonding. The retainers presented similar debonding forces but different failure types. Braided stainless steel wire retainers presented the most repairable failure type. PMID:24015388

  15. The effects of 10 weeks of resistance training combined with beta-alanine supplementation on whole body strength, force production, muscular endurance and body composition.

    PubMed

    Kendrick, Iain P; Harris, Roger C; Kim, Hyo Jeong; Kim, Chang Keun; Dang, Viet H; Lam, Thanh Q; Bui, Toai T; Smith, Marcus; Wise, John A

    2008-05-01

    Carnosine (Carn) occurs in high concentrations in skeletal muscle is a potent physico-chemical buffer of H+ over the physiological range. Recent research has demonstrated that 6.4 g x day(-1) of beta-alanine (beta-ala) can significantly increase skeletal muscle Carn concentrations (M-[Carn]) whilst the resultant change in buffering capacity has been shown to be paralleled by significant improvements in anaerobic and aerobic measures of exercise performance. Muscle carnosine increase has also been linked to increased work done during resistance training. Prior research has suggested that strength training may also increase M-[Carn] although this is disputed by other studies. The aim of this investigation is to assess the effect of 10 weeks resistance training on M-[Carn], and, secondly, to investigate if increased M-[Carn] brought about through beta-ala supplementation had a positive effect on training responses. Twenty-six Vietnamese sports science students completed the study. The subjects completed a 10-week resistance-training program whilst consuming 6.4 g x day(-1) of beta-ala (beta-ALG) or a matched dose of a placebo (PLG). Subjects were assessed prior to and after training for whole body strength, isokinetic force production, muscular endurance, body composition. beta-Alanine supplemented subjects increased M-[Carn] by 12.81 +/- 7.97 mmol x kg(-1) dry muscle whilst there was no change in PLG subjects. There was no significant effect of beta-ala supplementation on any of the exercise parameters measured, mass or % body fat. In conclusion, 10 weeks of resistance training alone did not change M-[Carn]. PMID:18175046

  16. Mitigation Action Plan

    SciTech Connect

    Not Available

    1994-02-01

    This Mitigation Action Plan (MAP) focuses on mitigation commitments stated in the Supplemental Environmental Impact Statement (SEIS) and the Record of Decision (ROD) for the Naval Petroleum Reserve No. 1 (NPR-1). Specific commitments and mitigation implementation actions are listed in Appendix A-Mitigation Actions, and form the central focus of this MAP. They will be updated as needed to allow for organizational, regulatory, or policy changes. It is the intent of DOE to comply with all applicable federal, state, and local environmental, safety, and health laws and regulations. Eighty-six specific commitments were identified in the SEIS and associated ROD which pertain to continued operation of NPR-1 with petroleum production at the Maximum Efficient Rate (MER). The mitigation measures proposed are expected to reduce impacts as much as feasible, however, as experience is gained in actual implementation of these measures, some changes may be warranted.

  17. The influence of wind resistance in running and walking and the mechanical efficiency of work against horizontal or vertical forces

    PubMed Central

    Pugh, L. G. C. E.

    1971-01-01

    1. O2 intakes were determined on subjects running and walking at various constant speeds, (a) against wind of up to 18·5 m/sec (37 knots) in velocity, and (b) on gradients ranging from 2 to 8%. 2. In running and walking against wind, O2 intakes increased as the square of wind velocity. 3. In running on gradients the relation of O2 intake and lifting work was linear and independent of speed. In walking on gradients the relation was linear at work rates above 300 kg m/min, but curvilinear at lower work rates. 4. In a 65 kg athlete running at 4·45 m/sec (marathon speed) V̇O2 increased from 3·0 l./min with minimal wind to 5·0 l./min at a wind velocity of 18·5 m/sec. The corresponding values for a 75 kg subject walking at 1·25 m/sec were 0·8 l./min with minimal wind and 3·1 l./min at a wind velocity of 18·5 m/sec. 5. Direct measurements of wind pressure on shapes of similar area to one of the subjects yielded higher values than those predicted from the relation of wind velocity and lifting work at equal O2 intakes. Horizontal work against wind was more efficient than vertical work against gravity. 6. The energy cost of overcoming air resistance in track running may be 7·5% of the total energy cost at middle distance speed and 13% at sprint speed. Running 1 m behind another runner virtually eliminated air resistance and reduced V̇O2 by 6·5% at middle distance speed. PMID:5574828

  18. Ground Reaction Force and Mechanical Differences Between the Interim Resistive Exercise Device (iRED) and Smith Machine While Performing a Squat

    NASA Technical Reports Server (NTRS)

    Amonette, William E.; Bentley, Jason R.; Lee, Stuart M. C.; Loehr, James A.; Schneider, Suzanne

    2004-01-01

    Musculoskeletal unloading in microgravity has been shown to induce losses in bone mineral density, muscle cross-sectional area, and muscle strength. Currently, an Interim Resistive Exercise Device (iRED) is being flown on board the ISS to help counteract these losses. Free weight training has shown successful positive musculoskeletal adaptations. In biomechanical research, ground reaction forces (GRF) trajectories are used to define differences between exercise devices. The purpose of this evaluation is to quantify the differences in GRF between the iRED and free weight exercise performed on a Smith machine during a squat. Due to the differences in resistance properties, inertial loading and load application to the body between the two devices, we hypothesize that subjects using iRED will produce GRF that are significantly different from the Smith machine. There will be differences in bar/harness range of motion and the time when peak GRF occurred in the ROMbar. Three male subjects performed three sets of ten squats on the iRED and on the Smith Machine on two separate days at a 2-second cadence. Statistically significant differences were found between the two devices in all measured GRF variables. Average Fz and Fx during the Smith machine squat were significantly higher than iRED. Average Fy (16.82 plus or minus.23; p less than .043) was significantly lower during the Smith machine squat. The mean descent/ascent ratio of the magnitude of the resultant force vector of all three axes for the Smith machine and iRED was 0.95 and 0.72, respectively. Also, the point at which maximum Fz occurred in the range of motion (Dzpeak) was at different locations with the two devices.

  19. Characterization of heat loads from mitigated and unmitigated vertical displacement events in DIII-D

    SciTech Connect

    Hollmann, E. M.; Moyer, R. A.; Commaux, N.; Jernigan, T. J.; Eidietis, N. W.; Humphreys, D. A.; Strait, E. J.; Wesley, J. C.; Lasnier, C. J.; Pitts, R. A.; Sugihara, M.; Watkins, J.

    2013-06-15

    Experiments have been conducted on the DIII-D tokamak to study the distribution and repeatability of heat loads and vessel currents resulting from vertical displacement events (VDEs). For unmitigated VDEs, the radiated power fraction appears to be of order 50%, with the remaining power dominantly conducted to the vessel walls. Shot-to-shot scatter in heat loads measured at one toroidal location is not large (<±50%), suggesting that toroidal asymmetries in conducted heat loads are not large. Conducted heat loads are clearly observed during the current quench (CQ) of both mitigated and unmitigated disruptions. Significant poloidal asymmetries in heat loads and radiated power are often observed in the experiments but are not yet understood. Energy dissipated resistively in the conducting walls during the CQ appears to be small (<5%). The mitigating effect of neon massive gas injection (MGI) as a function of MGI trigger delay has also been studied. Improved mitigation is observed as the MGI trigger delay is decreased. For sufficiently early MGI mitigation, close to 100% radiated energy and a reduction of roughly a factor 2 in vessel forces is achieved.

  20. Atrial natriuretic peptide down-regulates neutrophil recruitment on inflamed endothelium by reducing cell deformability and resistance to detachment force

    PubMed Central

    Morikis, Vasilios A.; Radecke, Chris; Jiang, Yanyan; Heinrich, Volkmar; Curry, Fitz-Roy; Simon, Scott I.

    2016-01-01

    BACKGROUND Recombinant atrial natriuretic peptide (ANP) is administered in patients with acute heart failure in Japan to improve renal function and hemodynamics, but its anti-inflammatory effect on activated leukocytes may also contribute to its therapeutic efficacy. OBJECTIVE Examine unconventional role of ANP in neutrophil adhesion to inflamed endothelium. METHODS Human neutrophils were perfused over endothelial monolayers in a microfluidic lab-chip assay. Cell rheology was assessed by micropipette aspiration to assess changes in cortical tension and viscosity. Fluorescence microscopy was applied to measure adhesive contact area and β2-integrin focal bond formation. RESULTS ANP inhibited neutrophil rolling and firm adhesion without influencing the upregulation of cellular adhesion molecules on endothelium or the regulation of high affinity CD18 and shedding of L-selectin during neutrophil activation. Exposed to fluid shear, integrin mediated arrest was disrupted with ANP treatment, which elicited formation of long tethers and diminished cell spreading and contact. This correlated with a ~40% increase in neutrophil viscosity and a reduction in the adhesive footprint. CONCLUSIONS A decrease in cell deformation and neutrophil flattening with ANP results in fewer integrin bond clusters, which translates to higher tensile forces and impaired adhesion strengthening and cell detachment. PMID:26639357

  1. Impact of lateral force-resisting system and design/construction practices on seismic performance and cost of tall buildings in Dubai, UAE

    NASA Astrophysics Data System (ADS)

    AlHamaydeh, Mohammad; Galal, Khaled; Yehia, Sherif

    2013-09-01

    The local design and construction practices in the United Arab Emirates (UAE), together with Dubai's unique rate of development, warrant special attention to the selection of Lateral Force-Resisting Systems (LFRS). This research proposes four different feasible solutions for the selection of the LFRS for tall buildings and quantifies the impact of these selections on seismic performance and cost. The systems considered are: Steel Special Moment-Resisting Frame (SMRF), Concrete SMRF, Steel Dual System (SMRF with Special Steel Plates Shear Wall, SPSW), and Concrete Dual System (SMRF with Special Concrete Shear Wall, SCSW). The LFRS selection is driven by seismic setup as well as the adopted design and construction practices in Dubai. It is found that the concrete design alternatives are consistently less expensive than their steel counterparts. The steel dual system is expected to have the least damage based on its relatively lesser interstory drifts. However, this preferred performance comes at a higher initial construction cost. Conversely, the steel SMRF system is expected to have the most damage and associated repair cost due to its excessive flexibility. The two concrete alternatives are expected to have relatively moderate damage and repair costs in addition to their lesser initial construction cost.

  2. Forced extinction of CD24 stem-like breast cancer marker alone promotes radiation resistance through the control of oxidative stress.

    PubMed

    Bensimon, Julie; Biard, Denis; Paget, Vincent; Goislard, Maud; Morel-Altmeyer, Sandrine; Konge, Julie; Chevillard, Sylvie; Lebeau, Jérôme

    2016-03-01

    Along with CD44, CD24 is a key marker of breast cancer stem cells (CSCs), frequently defined by CD24(-)/CD44(+) labeling. Among all phenotypes classically attributed to breast CD24(-)/CD44(+) cancer cells, radiation resistance has been extensively described and seen as being implicated in radiotherapy failure. Our previous data indicated that CD24(-) cells constitute a radiation-resistant subpopulation transitory selected by high doses of ionizing radiation. However, little is known about the biological role of CD24 in breast cancers, and no function has been assigned to CD24 in radiation response. Here, CD24 expression was induced in CD24(-) cells or knocked-down in CD24(+) cells. We show that forced extinction of CD24 expression is associated with decreased proliferation rate, lower levels of reactive oxygen species (ROS) and decreased genomic instability. On the opposite when CD24 is artificially expressed in CD24(-) cells, proliferation rates in vitro and in vivo, ROS levels and genomic instability are enhanced. Moreover, we observe that loss of CD24 expression leads to radiation resistance, by preventing radiation-induced cell death and promoting generation of progeny in relation to lower G2/M blockade and a smaller proportion of polyploid cells. Finally, control of ROS levels appears to be the key event in the CD24-mediated radiation response. For the first time, CD24 is proposed as a direct actor in radiation response of breast cancer cells, independently of CD44 expression. These findings could have interesting applications in evaluating the intrinsic radiation response of primary tumors. PMID:25641732

  3. Mitigation Monitoring Plan

    SciTech Connect

    Not Available

    1992-09-01

    The Final Supplemental Environmental Impact Report (SEIR) (September 1992) for the Proposed Renewal of the Contract between the United States Department of Energy and The Regents of the University of California for the Operation and Management of the Lawrence Berkeley Laboratory identifies the environmental impacts associated with renewing the contract and specifies a series of measures designed to mitigate adverse impacts to the environment. This Mitigation Monitoring Plan describes the procedures the University will use to implement the mitigation measures adopted in connection with the approval of the Contract.

  4. Driving forces of vancomycin-resistant E. faecium and E. faecalis blood-stream infections in children

    PubMed Central

    2014-01-01

    Background Rates of invasive vancomycin-resistant Enterococcus (VRE) in the USA remains on the rise. Efforts to control vancomycin use and nosocomial transmission have had limited success in halting the spread of this pathogen. The role of antibiotic exposure remains a topic of controversy. We evaluated the association between emergence of VRE-blood-stream infections (BSI), aggregate and individual-patient vancomycin- exposure, and clonal transmission of VRE at an academic pediatric tertiary care hospital. Methods E. faecium and E. faecalis isolates recovered from blood specimens from hospitalized children from 2003–2010 were retrieved from the microbiology database. Aggregate vancomycin use and individual-patient vancomycin exposure 6 months preceding each event of bacteremia were recorded. Pulse-field electrophoresis was performed on selected VRE isolates. Results Of 151 episodes of E. faecium and E. faecalis BSI among hospitalized children <18 years of age, 9% (14) were due to VRE. Of these, 5 (36%) were due to nosocomial transmission. Aggregate (r .19, P = 0.3) and individual-patient vancomycin-exposure (X 2  = .26; P = .87) were not associated with VRE-BSI. On bivariate analysis, OR for developing VRE-BSI among patients infected with clonal isolates was 36 (P < .0001). Infection control interventions, rather than antimicrobial stewardship interventions to decrease vancomycin use, proved to be effective in reducing the rates of VRE-BSI. Conclusions In our experience, VRE-BSI was associated with nosocomial transmission and was independent of aggregate and individual-patient vancomycin-exposure. Molecular epidemiology is a crucial tool to differentiate the role of nosocomial transmission and antibiotic exposure in the emergence of invasive VRE infections among hospitalized children. PMID:25206975

  5. Sidoarjo mudflow phenomenon and its mitigation efforts

    NASA Astrophysics Data System (ADS)

    Wibowo, H. T.; Williams, V.

    2009-12-01

    Hot mud first erupted in Siring village, Porong, Sidoarjo May 29th 2006. The mud first appeared approximately 200 meters from Banjarpanji-1 gas-drilling well. The mud volume increased day by day, from 5000 cubic meters per day on June 2006 to 50,000 cubic meters per day during the last of 2006, and then increased to 100,000-120,000 cubic meters per day during 2007. Flow still continues at a high rate. Moreover, as the water content has gone down, the clast content has gone up. Consequently, there is now the threat of large amounts of solid material being erupted throughout the area. Also, there is the issue of subsurface collapse and ground surface subsidence. The Indonesian government has set up a permanent team to support communities affected by the mudflow that has swamped a number of villages near LUSI. Toll roads, railway tracks and factories also have been submerged and over 35,000 people have been displaced to date. The Sidoarjo Mudflow Mitigation Agency [SMMA, BPLS (Indonesia)] replaces a temporary team called National Team PSLS which was installed for seven months and ended their work on 7 April 2007. BPLS was set up by Presidential Regulation No. 14 / 2007, and it will have to cover the costs related to the social impact of the disaster, especially outside the swamped area. BPLS is the central government institution designated to handle the disaster by coordination with both the drilling company and local (provincial and district) governments. It takes a comprehensive, integrated and holistic approach for its mission and challenges. Those are: 1) How to stop the mudflow, 2) How to mitigate the impacts of the mudflow, and 3) How to minimize the social, economic, environmental impacts, and infrastructure impacts. The mudflow mitigation efforts were constrained by dynamic geology conditions, as well as resistance to certain measures by residents of impacted areas. Giant dykes were built to retain the spreading mud, and the mudflow from the main vent was

  6. Lunar Dust Mitigation Screens

    NASA Astrophysics Data System (ADS)

    Knutson, Shawn; Holloway, Nancy

    With plans for the United States to return to the moon, and establish a sustainable human presence on the lunar surface many issues must be successfully overcome. Lunar dust is one of a number of issues with the potential to create a myriad of problems if not adequately addressed. Samples of dust brought back from Apollo missions show it to be soft, yet sharp and abrasive. The dust consists of a variety of morphologies including spherical, angular blocks, shards, and a number of irregular shapes. One of the main issues with lunar dust is its attraction to stick to anything it comes in contact with (i.e. astronauts, equipment, habitats, etc.). Ionized radiation from the sun strikes the moon's surface and creates an electrostatic charge on the dust. Further, the dust harbors van der Waals forces making it especially difficult to separate once it sticks to a surface. During the Apollo missions, it was discovered that trying to brush the lunar dust from spacesuits was not effective, and rubbing it caused degradation of the suit material. Further, when entering the lunar module after moonwalks, the astronauts noted that the dust was so prolific inside the cabin that they inhaled and ingested it, causing at least one of them, Harrison "Jack" Schmidt, to report irritation of the throat and lungs. It is speculated that the dust could also harm an astronaut's nervous and cardiovascular systems, especially during an extended stay. In addition to health issues, the dust can also cause problems by scouring reflective coatings off of thermal blankets, and roughening surfaces of windows and optics. Further, panels on solar cells and photovoltaics can also be compromised due to dust sticking on the surfaces. Lunar dust has the capacity to penetrate seals, interfere with connectors, as well as mechanisms on digging machines, all of which can lead to problems and failure. To address lunar dust issues, development of electrostatic screens to mitigate dust on sur-faces is currently

  7. Electronic Force Gage for Welders

    NASA Technical Reports Server (NTRS)

    Bradley, J. W.; Gates, G.

    1983-01-01

    Welding force monitored in process. Electronic force gage uses strain gage on deformable member. Oscilloscope trace of welding force photographed and compared with standard trace during calibration and troubleshooting of resistance welding equipment. Adaptable to small scale resistance welding in electronics industry.

  8. Orbital Debris Mitigation

    NASA Technical Reports Server (NTRS)

    Kelley, R. L.; Jarkey, D. R.; Stansbery, G.

    2014-01-01

    Policies on limiting orbital debris are found throughout the US Government, many foreign space agencies, and as adopted guidelines in the United Nations. The underlying purpose of these policies is to ensure the environment remains safe for the operation of robotic and human spacecraft in near- Earth orbit. For this reason, it is important to consider orbital debris mitigation during the design of all space vehicles. Documenting compliance with the debris mitigation guidelines occurs after the vehicle has already been designed and fabricated for many CubeSats, whereas larger satellites are evaluated throughout the design process. This paper will provide a brief explanation of the US Government Orbital Debris Mitigation Standard Practices, a discussion of international guidelines, as well as NASA's process for compliance evaluation. In addition, it will discuss the educational value of considering orbital debris mitigation requirements as a part of student built satellite design.

  9. Mitigation win-win

    NASA Astrophysics Data System (ADS)

    Moran, Dominic; Lucas, Amanda; Barnes, Andrew

    2013-07-01

    Win-win messages regarding climate change mitigation policies in agriculture tend to oversimplify farmer motivation. Contributions from psychology, cultural evolution and behavioural economics should help to design more effective policy.

  10. Policy thresholds in mitigation

    NASA Astrophysics Data System (ADS)

    Ricke, Katharine L.; Moreno-Cruz, Juan B.; Schewe, Jacob; Levermann, Anders; Caldeira, Ken

    2016-01-01

    Some climate change impacts rise fast with little warming, and then taper off. To avoid diminishing incentives to reduce emissions and inadvertently slipping into a lower-welfare world, mitigation policy needs to be ambitious early on.

  11. Adaptive magnetorheological seat suspension for shock mitigation

    NASA Astrophysics Data System (ADS)

    Singh, Harinder J.; Wereley, Norman M.

    2013-04-01

    An adaptive magnetorheological seat suspension (AMSS) was analyzed for optimal protection of occupants from shock loads caused by the impact of a helicopter with the ground. The AMSS system consists of an adaptive linear stroke magnetorheological shock absorber (MRSA) integrated into the seat structure of a helicopter. The MRSA provides a large controllability yield force to accommodate a wide spectrum for shock mitigation. A multiple degrees-of-freedom nonlinear biodynamic model for a 50th percentile male occupant was integrated with the dynamics of MRSA and the governing equations of motion were investigated theoretically. The load-stroke profile of MRSA was optimized with the goal of minimizing the potential for injuries. The MRSA yield force and the shock absorber stroke limitations were the most crucial parameters for improved biodynamic response mitigation. An assessment of injuries based on established injury criteria for different body parts was carried out.

  12. Platelet Composite Coatings for Tin Whisker Mitigation

    NASA Astrophysics Data System (ADS)

    Rohwer, Lauren E. S.; Martin, James E.

    2015-11-01

    Reliable methods for tin whisker mitigation are needed for applications that utilize tin-plated commercial components. Tin can grow whiskers that can lead to electrical shorting, possibly causing critical systems to fail catastrophically. The mechanisms of tin whisker growth are unclear and this makes prediction of the lifetimes of critical components uncertain. The development of robust methods for tin whisker mitigation is currently the best approach to eliminating the risk of shorting. Current mitigation methods are based on unfilled polymer coatings that are not impenetrable to tin whiskers. In this paper we report tin whisker mitigation results for several filled polymer coatings. The whisker-penetration resistance of the coatings was evaluated at elevated temperature and high humidity and under temperature cycling conditions. The composite coatings comprised Ni and MgF2-coated Al/Ni/Al platelets in epoxy resin or silicone rubber. In addition to improved whisker mitigation, these platelet composites have enhanced thermal conductivity and dielectric constant compared with unfilled polymers.

  13. Platelet composite coatings for tin whisker mitigation

    DOE PAGESBeta

    Rohwer, Lauren E. S.; Martin, James E.

    2015-09-14

    In this study, reliable methods for tin whisker mitigation are needed for applications that utilize tin-plated commercial components. Tin can grow whiskers that can lead to electrical shorting, possibly causing critical systems to fail catastrophically. The mechanisms of tin whisker growth are unclear and this makes prediction of the lifetimes of critical components uncertain. The development of robust methods for tin whisker mitigation is currently the best approach to eliminating the risk of shorting. Current mitigation methods are based on unfilled polymer coatings that are not impenetrable to tin whiskers. In this paper we report tin whisker mitigation results formore » several filled polymer coatings. The whisker-penetration resistance of the coatings was evaluated at elevated temperature and high humidity and under temperature cycling conditions. The composite coatings comprised Ni and MgF2-coated Al/Ni/Al platelets in epoxy resin or silicone rubber. In addition to improved whisker mitigation, these platelet composites have enhanced thermal conductivity and dielectric constant compared with unfilled polymers.« less

  14. Platelet composite coatings for tin whisker mitigation

    SciTech Connect

    Rohwer, Lauren E. S.; Martin, James E.

    2015-09-14

    In this study, reliable methods for tin whisker mitigation are needed for applications that utilize tin-plated commercial components. Tin can grow whiskers that can lead to electrical shorting, possibly causing critical systems to fail catastrophically. The mechanisms of tin whisker growth are unclear and this makes prediction of the lifetimes of critical components uncertain. The development of robust methods for tin whisker mitigation is currently the best approach to eliminating the risk of shorting. Current mitigation methods are based on unfilled polymer coatings that are not impenetrable to tin whiskers. In this paper we report tin whisker mitigation results for several filled polymer coatings. The whisker-penetration resistance of the coatings was evaluated at elevated temperature and high humidity and under temperature cycling conditions. The composite coatings comprised Ni and MgF2-coated Al/Ni/Al platelets in epoxy resin or silicone rubber. In addition to improved whisker mitigation, these platelet composites have enhanced thermal conductivity and dielectric constant compared with unfilled polymers.

  15. Forced oscillation technique. Reference values for resistance and reactance over a frequency spectrum of 2-26 Hz in healthy children aged 2.3-12.5 years.

    PubMed

    Duiverman, E J; Clément, J; van de Woestijne, K P; Neijens, H J; van den Bergh, A C; Kerrebijn, K F

    1985-01-01

    The forced pseudo-random noise oscillation technique is a method by which total respiratory resistance (Rrs) and reactance (Xrs) can be measured simultaneously at various frequencies by means of complex oscillations, superimposed at the mouth during spontaneous quiet breathing. Reference values were obtained in 255 healthy Caucasian children of Dutch descent aged 2.3-12.5 years. Rrs and Xrs vs frequency (f) curves are mainly determined by the child's sex, age, height and weight. Taking complete Rrs and Xrs-f curves into account, we found that Rrs values were significantly higher in young boys than in young girls. They were equal at about 8 years, but at about 12 years of age Rrs values were again significantly higher in boys than in girls. Frequency dependence of Rrs was found in healthy boys up to about 5 years of age, but not in girls of the same age or in older children. These data suggest differences in airway diameter between boys and girls. At all ages Xrs was significantly lower in boys than in girls. This suggests differences in bronchial patency of peripheral airways, boys being at a disadvantage. It is concluded that multiple frequency oscillometry is a method which is ideal for children from the age of about 3 years. The possibility of measuring Rrs as well as frequency dependence of Rrs and Xrs simultaneously is the major advantage over other oscillation devices. PMID:3995199

  16. Satellite Breakup Risk Mitigation

    NASA Technical Reports Server (NTRS)

    Leleux, Darrin P.; Smith, Jason T.

    2006-01-01

    Many satellite breakups occur as a result of an explosion of stored energy on-board spacecraft or rocket-bodies. These breakups generate a cloud of tens or possibly hundreds of thousands of debris fragments which may pose a transient elevated threat to spaceflight crews and vehicles. Satellite breakups pose a unique threat because the majority of the debris fragments are too small to be tracked from the ground. The United States Human Spaceflight Program is currently implementing a risk mitigation strategy that includes modeling breakup events, establishing action thresholds, and prescribing corresponding mitigation actions in response to satellite breakups.

  17. Financing recreational mitigation

    SciTech Connect

    Hennagir, T.

    1995-07-01

    Recreational resource area mitigation remains an important operational requirement for hydropower project owners, especially in the western United States. Increasingly, producers of electric capacity must accommodate a rapidly growing demand for public recreation, providing opportunities in accordance with Federal Energy Regulatory Commission (FERC) relicensing requirements.

  18. Space Debris Mitigation Guidelines

    NASA Technical Reports Server (NTRS)

    Johnson, Nicholas L.

    2011-01-01

    The purpose of national and international space debris mitigation guides is to promote the preservation of near-Earth space for applications and exploration missions far into the future. To accomplish this objective, the accumulation of objects, particularly in long-lived orbits, must be eliminated or curtailed.

  19. Mitigating Infectious Disease Outbreaks

    NASA Astrophysics Data System (ADS)

    Davey, Victoria

    The emergence of new, transmissible infections poses a significant threat to human populations. As the 2009 novel influenza A/H1N1 pandemic and the 2014-2015 Ebola epidemic demonstrate, we have observed the effects of rapid spread of illness in non-immune populations and experienced disturbing uncertainty about future potential for human suffering and societal disruption. Clinical and epidemiologic characteristics of a newly emerged infectious organism are usually gathered in retrospect as the outbreak evolves and affects populations. Knowledge of potential effects of outbreaks and epidemics and most importantly, mitigation at community, regional, national and global levels is needed to inform policy that will prepare and protect people. Study of possible outcomes of evolving epidemics and application of mitigation strategies is not possible in observational or experimental research designs, but computational modeling allows conduct of `virtual' experiments. Results of well-designed computer simulations can aid in the selection and implementation of strategies that limit illness and death, and maintain systems of healthcare and other critical resources that are vital to public protection. Mitigating Infectious Disease Outbreaks.

  20. Forced marriage, forced sex: the perils of childhood for girls.

    PubMed

    Ouattara, M; Sen, P; Thomson, M

    1998-11-01

    A recently formed interagency Forum on the Rights of Girls and Women in Marriage is investigating the widespread problem of nonconsensual marriage and forced sex and advocating for legislative and policy initiatives. This article reviews three research projects in this area: research by Anti-Slavery International on child marriage in parts of West Africa, an investigation by Save the Children of children's views of early marriage, and research conducted by CHANGE on women's resistance to domestic violence in Calcutta, India. Girls who marry before 15 years of age are more likely to be illiterate than their older counterparts, more likely to be dowry payment brides, less likely to come into contact with development projects, have higher rates of infant mortality, and are most vulnerable to sexual violence. In many cases, intercourse is initiated before the girl begins to menstruate. Although adult women also face sexual violence within marriage, this problem is all the more traumatic for girls who lack any information about sexuality. Sex with girls below a certain age is usually covered by rape legislation, but, in countries such as India, this is mitigated by the religiously defined personal laws. The absence of adequate legal and policy action frameworks to deal with the rights of girls, coupled with the lack of sanctions against these abuses, comprise state complicity and neglect of duty under international law to this vulnerable group. PMID:12294409

  1. Optical Forces on Metastable Helium

    NASA Astrophysics Data System (ADS)

    Corder, Christopher Scott

    Optical forces using lasers allow precise control over the motion of atoms. The bichromatic optical force (BF) is unique in its large magnitude and velocity range, arising from the absorption and stimulated emission processes. These properties were used to transversely collimate a beam of metastable helium (He*) using the 23S - 23P transition. The collimation created a very bright beam of He*, allowing experiments of neutral atom lithography. The He* beam was used to pattern material surfaces using a resist-based lithography technique, where the pattern was determined by either mechanical or optical masks. The optical masks produced features with a separation of half the wavelength of the light used. Patterning was successfully demonstrated with both IR and UV optical masks. The etched pattern resolution was ˜ 100 nm and limited by the material surface. Further experiments were performed studying the ability of the bichromatic force to cool. The finite velocity range of the BF allows estimation of a characteristic cooling time which is independent of the excited state lifetime, only depending on the atomic mass and optical transition energy. Past experiments, including the helium collimation used for neutral atom lithography, have demonstrated that the BF can collimate and longitudinally slow atomic beams, but required long interaction times that included many spontaneous emission (SE) events. The effect of SE can be mitigated, and is predicted to not be necessary for BF cooling. Since the BF cooling time is not related to the excited state lifetime, a transition can be chosen such that the cooling time is shorter than the SE cycle time, allowing direct laser cooling on atoms and molecules that do not have cycling transitions. Experiments using the helium 2 3S-3P transition were chosen because the BF cooling time (285 ns) is on the order of the average SE cycle time (260 ns). Numerical simulations of the experimental system were run predicting compression of the

  2. Feasible mitigation actions in developing countries

    NASA Astrophysics Data System (ADS)

    Jakob, Michael; Steckel, Jan Christoph; Klasen, Stephan; Lay, Jann; Grunewald, Nicole; Martínez-Zarzoso, Inmaculada; Renner, Sebastian; Edenhofer, Ottmar

    2014-11-01

    Energy use is not only crucial for economic development, but is also the main driver of greenhouse-gas emissions. Developing countries can reduce emissions and thrive only if economic growth is disentangled from energy-related emissions. Although possible in theory, the required energy-system transformation would impose considerable costs on developing nations. Developed countries could bear those costs fully, but policy design should avoid a possible 'climate rent curse', that is, a negative impact of financial inflows on recipients' economies. Mitigation measures could meet further resistance because of adverse distributional impacts as well as political economy reasons. Hence, drastically re-orienting development paths towards low-carbon growth in developing countries is not very realistic. Efforts should rather focus on 'feasible mitigation actions' such as fossil-fuel subsidy reform, decentralized modern energy and fuel switching in the power sector.

  3. The Role of Non-CO2 Greenhouse Gases and Aerosols in Climate Mitigation

    SciTech Connect

    Smith, Steven J.; Bond, Tami C.; Wigley, Tom M.; de la Chesnaye, Francisco; Pitcher, Hugh M.

    2003-11-17

    Forcing agents other than carbon dioxide, such as methane, nitrous oxide, halocarbons, and perhaps aerosol particles, may play a major role in mitigating climate change. Of these agents, methane is the most important greenhouse gas and has substantial mitigation potential. The role of black and organic carbon aerosols has attracted increasing interest and we explicitly include these carbonaceous aerosols in our calculations. This paper analyzes the potential role of different forcing agents in reducing future climate forcing in a multi-gas, integrated assessment model in which mitigation options compete and interact. Our framework includes all of the important atmospheric forcing agents: carbon dioxide, methane, nitrous oxide, halocarbons, sulfur dioxide, and carbonaceous aerosols along with an array of potential mitigation options. Through an integrated analysis of all available options we present a realistic portrait of the potential role of these forcing agents in limiting future climate change.

  4. Zebra mussel mitigation; overview

    SciTech Connect

    Claudi, R.

    1995-06-01

    Zebra mussels cause a number of problems to industrial raw water users as well as having serious impact on civil structures exposed to mussel infested waters. The largest volume of water (up to 90% of the total) drawn into most industrial and power generating plants, is for cooling and heat transfer. The rest of the volume is used for other plant processes, such as make-up in steam systems, and service systems used for cleaning, air conditions, fire protection and human consumption. All raw water systems are vulnerable to zebra mussel infestation to greater or lesser degree. To-date, many different chemical and non-chemical techniques for zebra mussel control have been investigated. However, the treatment of choice for most facilities is based on chemical control. This has been the common practice in Europe and so far it has been the case in North America. This is likely to change as the environmental constraints on release of chemicals into natural water bodies continue to increase. This paper deals with the different steps raw water users should take when deciding on a mitigation strategy, the mitigation measures available to-date and those that have been proposed for the control of zebra mussels in industrial systems.

  5. Optimal Design of Honeycomb Material Used to Mitigate Head Impact

    PubMed Central

    Caccese, Vincent; Ferguson, James R.; Edgecomb, Michael

    2013-01-01

    This paper presents a study of the impact resistance of honeycomb structure with the purpose to mitigate impact forces. The objective is to aid in the choice of optimal parameters to minimize the thickness of the honeycomb structure while providing adequate protection to prevent injury due to head impact. Studies are presented using explicit finite element analysis representing the case of an unprotected drop of a rigid impactor onto a simulated floor consisting of vinyl composition tile and concrete. Analysis of honeycomb material to reduce resulting accelerations is also presented where parameters such as honeycomb material modulus, wall thickness, cell geometry and structure depth are compared to the unprotected case. A simplified analysis technique using a genetic algorithm is presented to demonstrate the use of this method to select a minimum honeycomb depth to achieve a desired acceleration level at a given level of input energy. It is important to select a minimum material depth in that smaller dimensions lead toward more aesthetic design that increase the likelihood of that the device is used. PMID:23976812

  6. Effect of current compliance and voltage sweep rate on the resistive switching of HfO{sub 2}/ITO/Invar structure as measured by conductive atomic force microscopy

    SciTech Connect

    Wu, You-Lin Liao, Chun-Wei; Ling, Jing-Jenn

    2014-06-16

    The electrical characterization of HfO{sub 2}/ITO/Invar resistive switching memory structure was studied using conductive atomic force microscopy (AFM) with a semiconductor parameter analyzer, Agilent 4156C. The metal alloy Invar was used as the metal substrate to ensure good ohmic contact with the substrate holder of the AFM. A conductive Pt/Ir AFM tip was placed in direct contact with the HfO{sub 2} surface, such that it acted as the top electrode. Nanoscale current-voltage (I-V) characteristics of the HfO{sub 2}/ITO/Invar structure were measured by applying a ramp voltage through the conductive AFM tip at various current compliances and ramp voltage sweep rates. It was found that the resistance of the low resistance state (RLRS) decreased with increasing current compliance value, but resistance of high resistance state (RHRS) barely changed. However, both the RHRS and RLRS decreased as the voltage sweep rate increased. The reasons for this dependency on current compliance and voltage sweep rate are discussed.

  7. National Standard of the Russian Federation for Space Debris Mitigation

    NASA Astrophysics Data System (ADS)

    Loginov, S.; Yakovlev, M.; Mikhailov, M.; Popkova, L.

    2009-03-01

    Normative and technical document that define requirements for the mitigation of human-produced near-earth space pollution develops in Russian Federation.NATIONAL STANDARD of the Russian Federation GOST R 52925-2008 «SPACE TECHNOLOGY ITEMS. General Requirements on Space Systems for the Mitigation of Human-Produced near-Earth Space Pollution» was approved in 2008 and entered into force since 1st January of 2009. Requirements of this standard harmonized with requirements of «UN SPACE DEBRIS MITIGATION GUIDELINESÈ»This standard consists of six parts:- Scope;- References to Standards;- Terms & Definitions;- Abbreviations;- General Provisions;- General Requirements on Space Systems for the Mitigation of Human-Produced near-Earth Space Pollution.

  8. Copolyimide Surface Modifying Agents for Particle Adhesion Mitigation

    NASA Technical Reports Server (NTRS)

    Wohl, Christopher J.; Connell, John W.

    2011-01-01

    Marine biofouling, insect adhesion on aircraft surfaces, microbial contamination of sterile environments, and particle contamination all present unique challenges for which researchers have adopted an array of mitigation strategies. Particulate contamination is of interest to NASA regarding exploration of the Moon, Mars, asteroids, etc.1 Lunar dust compromised seals, clogged filters, abraded visors and space suit surfaces, and was a significant health concern during the Apollo missions.2 Consequently, NASA has instituted a multi-faceted approach to address dust including use of sacrificial surfaces, active mitigation requiring the use of an external energy source, and passive mitigation utilizing materials with an intrinsic resistance to surface contamination. One passive mitigation strategy is modification of a material s surface energy either chemically or topographically. The focus of this paper is the synthesis and evaluation of novel copolyimide materials with surface modifying agents (SMA, oxetanes) enabling controlled variation of surface chemical composition.

  9. The Cytoskeleton and Force Response Mechanisms

    NASA Technical Reports Server (NTRS)

    Allen, Philip Goodwin

    2003-01-01

    The long term aim of this project was to define the mechanisms by which cells sense and respond to the physical forces experienced at 1g and missing in microgravity. Identification and characterization of the elements of the cells force response mechanism could provide pathways and molecules to serve as targets for pharmacological intervention to mitigate the pathologic effects of microgravity. Mechanical forces experienced by the organism can be transmitted to cells through molecules that allow cells to bind to the extracellular matrix and through other types of molecules which bind cells to each other. These molecules are coupled in large complexes of proteins to structural elements such as the actin cytoskeleton that give the cell the ability to sense, resist and respond to force. Application of small forces to tissue culture cells causes local elevation of intracellular calcium through stretch activated ion channels, increased tyrosine phosphorylation and a restructuring of the actin cytoskeleton. Using collagen coated iron oxide beads and strong magnets, we can apply different levels of force to cells in culture. We have found that force application causes the cells to polymerize actin at the site of mechanical deformation and unexpectedly, to depolymerize actin across the rest of the cell. Observations of GFP- actin expressing cells demonstrate that actin accumulates at the site of deformation within the first five minutes of force application and is maintained for many tens of minutes after force is removed. Consistent with the reinforcement of the cytoskeletal structures underlying the integrin-bead interaction, force also alters the motion of bound magnetic beads. This effect is seen following the removal of the magnetic field, and is only partially ablated by actin disruption with cytochalsin B. While actin is polymerizing locally at the site of force application, force also stimulates a global reduction in actin filament content within the cells. We have

  10. Optimization of Massive Impurity Injection Techniques for Thermal Quench Mitigation and Current Quench Control on DIII-D

    NASA Astrophysics Data System (ADS)

    Shiraki, D.

    2015-11-01

    Recent DIII-D experiments demonstrate the ability of massive impurity injection techniques to effectively control current quench (CQ) timescales and thermal quench (TQ) radiation fractions, which are essential design requirements for the ITER disruption mitigation system (DMS). Allowable CQ timescales for ITER are constrained by both a lower bound due to eddy current forces as well as an upper bound due to halo currents, and this must be achieved while maintaining sufficiently high radiated powers to minimize thermal loads. The DIII-D shattered pellet injection system has been modified to allow formation of mixed species pellets with variable quantities of high-Z radiating impurities (Ne) and main ions (D2) , which is shown to provide control of TQ radiation fractions and the resulting post-TQ plasma resistivity which determines the CQ rate. By varying the pellet composition ranging from pure D2 to pure Ne, TQ radiation fractions are observed to saturate with modest quantities of Ne, indicating that relatively small quantities of the radiating impurity provide effective thermal mitigation. Resulting CQ durations are found to remain within scaled eddy and halo current limits predicted for ITER, demonstrating that integrated control of TQ and CQ properties during disruption mitigation can be achieved. The effectiveness of these mitigation techniques in disruptive plasma scenarios with large MHD instabilities is also crucial for ITER. Such effects are observed to lead to increased assimilation of injected impurities during the TQ, implying the importance of MHD mixing during the initial assimilation. Longer timescale CQ metrics are relatively unaffected by the pre-existing MHD activity, allowing effective mitigation of electromagnetic loads. These results provide further confidence in the implementation of these injection techniques in the final design of the ITER DMS. Supported by the US DOE under DE-AC05-00OR22725 and DE-FC02-04ER54698.

  11. Climate change and mitigation.

    PubMed

    Nibleus, Kerstin; Lundin, Rickard

    2010-01-01

    Planet Earth has experienced repeated changes of its climate throughout time. Periods warmer than today as well as much colder, during glacial episodes, have alternated. In our time, rapid population growth with increased demand for natural resources and energy, has made society increasingly vulnerable to environmental changes, both natural and those caused by man; human activity is clearly affecting the radiation balance of the Earth. In the session "Climate Change and Mitigation" the speakers offered four different views on coal and CO2: the basis for life, but also a major hazard with impact on Earth's climate. A common denominator in the presentations was that more than ever science and technology is required. We need not only understand the mechanisms for climate change and climate variability, we also need to identify means to remedy the anthropogenic influence on Earth's climate. PMID:20873680

  12. RFI Mitigation for FAST

    NASA Astrophysics Data System (ADS)

    Zhang, Haiyan; Nan, Rendong; Gan, Hengqian; Yue, Youling; Wu, Mingchang; Zhang, Zhiwei; Jin, Chengjin; Peng, Bo

    2015-08-01

    Five-hundred-meter Aperture Spherical radio Telescope (FAST) is a Chinese mega-science project to build the largest single dish radio telescope in the world. The construction was officially commenced in March 2011. The first light of FAST is expected in 2016. Due to the high sensitivity of FAST, Radio Frequency Interference (RFI) mitigation for the telescope is required to assure the realization of the scientific goals. In order to protect the radio environment of FAST site, the local government has established a radio quiet zone with 30 km radius. Moreover, Electromagnetic Compatibility (EMC) designs and measurements for FAST have also been carried out, and some examples, such as EMC designs for actuator and focus cabin, have been introduced briefly.

  13. Computational Models of Exercise on the Advanced Resistance Exercise Device (ARED)

    NASA Technical Reports Server (NTRS)

    Newby, Nate; Caldwell, Erin; Scott-Pandorf, Melissa; Peters,Brian; Fincke, Renita; DeWitt, John; Poutz-Snyder, Lori

    2011-01-01

    Muscle and bone loss remain a concern for crew returning from space flight. The advanced resistance exercise device (ARED) is used for on-orbit resistance exercise to help mitigate these losses. However, characterization of how the ARED loads the body in microgravity has yet to be determined. Computational models allow us to analyze ARED exercise in both 1G and 0G environments. To this end, biomechanical models of the squat, single-leg squat, and deadlift exercise on the ARED have been developed to further investigate bone and muscle forces resulting from the exercises.

  14. Apparatus and Methods for Mitigating Electromagnetic Emissions

    NASA Technical Reports Server (NTRS)

    Geng, Steven M. (Inventor); Niedra, Janis M. (Inventor)

    2016-01-01

    Apparatus, methods, and other embodiments associated with mitigation of magnetic fields are described herein. In an embodiment, a method for mitigating an electromagnetic field includes positioning a mitigating coil around a linear alternator of linear motor so that the mitigating coil is coaxially located with an alternator coil; arranging the mitigating coil to generate a field to mitigate an electromagnetic field generated by the alternator coil; and passing an induced current from the alternator coil through the mitigating coil.

  15. Apparatus and Methods for Mitigating Electromagnetic Emissions

    NASA Technical Reports Server (NTRS)

    Geng, Steven M. (Inventor); Niedra, Janis M. (Inventor)

    2013-01-01

    Apparatus, methods, and other embodiments associated with mitigation of magnetic fields are described herein. In an embodiment, a method for mitigating an electromagnetic field includes positioning a mitigating coil around a linear alternator of linear motor so that the mitigating coil is coaxially located with an alternator coil; arranging the mitigating coil to generate a field to mitigate an electromagnetic field generated by the alternator coil; and passing an induced current from the alternator coil through the mitigating coil.

  16. Task Force IV: Environment and Natural Resources

    ERIC Educational Resources Information Center

    Appalachia, 1977

    1977-01-01

    Summarizing the Task Force Issues Paper presented at the Appalachian Conference on Balanced Growth and Economic Development (1977), this article presents Task Force recommendations on: the price of growth; relaxation of environmental regulations; mitigation of regional impact costs; policy regarding the use of public lands; growth management…

  17. RADON MITIGATION EFFECTS OF PASSIVE STACKS IN RESIDENTIAL NEW CONSTRUCTION

    EPA Science Inventory

    The paper discusses the effects of passive stacks in mitigating radon levels in residential new construction. Although passive stacks have been installed as a radon resistant measure in new houses, little quantitative data on their performance has been collected. This study invol...

  18. The battle against multi-resistant strains: Renaissance of antimicrobial essential oils as a promising force to fight hospital-acquired infections.

    PubMed

    Warnke, Patrick H; Becker, Stephan T; Podschun, Rainer; Sivananthan, Sureshan; Springer, Ingo N; Russo, Paul A J; Wiltfang, Joerg; Fickenscher, Helmut; Sherry, Eugene

    2009-10-01

    Hospital-acquired infections and antibiotic-resistant bacteria continue to be major health concerns worldwide. Particularly problematic is methicillin-resistant Staphylococcus aureus (MRSA) and its ability to cause severe soft tissue, bone or implant infections. First used by the Australian Aborigines, Tea tree oil and Eucalyptus oil (and several other essential oils) have each demonstrated promising efficacy against several bacteria and have been used clinically against multi-resistant strains. Several common and hospital-acquired bacterial and yeast isolates (6 Staphylococcus strains including MRSA, 4 Streptococcus strains and 3 Candida strains including Candida krusei) were tested for their susceptibility for Eucalyptus, Tea tree, Thyme white, Lavender, Lemon, Lemongrass, Cinnamon, Grapefruit, Clove Bud, Sandalwood, Peppermint, Kunzea and Sage oil with the agar diffusion test. Olive oil, Paraffin oil, Ethanol (70%), Povidone iodine, Chlorhexidine and hydrogen peroxide (H(2)O(2)) served as controls. Large prevailing effective zones of inhibition were observed for Thyme white, Lemon, Lemongrass and Cinnamon oil. The other oils also showed considerable efficacy. Remarkably, almost all tested oils demonstrated efficacy against hospital-acquired isolates and reference strains, whereas Olive and Paraffin oil from the control group produced no inhibition. As proven in vitro, essential oils represent a cheap and effective antiseptic topical treatment option even for antibiotic-resistant strains as MRSA and antimycotic-resistant Candida species. PMID:19473851

  19. MITIGATION IMPACT SCREENING TOOL (MIST)

    EPA Science Inventory

    MIST is intended to provide a back of the envelope, qualitative indication of the likely impacts of heat island mitigation strategies averaged at the city-scale. To run MIST, users follow three basic steps: 1. Select the city to model (240 available) 2. Define the mitigation ...

  20. Toward to Disaster Mitigation Science

    NASA Astrophysics Data System (ADS)

    Kaneda, Yoshiyuki; Shiraki, Wataru; Tokozakura, Eiji

    2016-04-01

    Destructive natural disasters such as earthquakes and tsunamis have occurred frequently in the world. For the reduction and mitigation of damages by destructive natural disasters, early detection of natural disasters and speedy and proper evacuations are indispensable. And hardware and software preparations for reduction and mitigation of natural disasters are quite important and significant. Finally, methods on restorations and revivals are necessary after natural disasters. We would like to propose natural disaster mitigation science for early detections, evacuations and restorations against destructive natural disasters. In natural disaster mitigation science, there are lots of research fields such as natural science, engineering, medical treatment, social science and literature/art etc. Especially, natural science, engineering and medical treatment are fundamental research fields for natural disaster mitigation, but social sciences such as sociology, psychology etc. are very important research fields for restorations after natural disasters. We have to progress the natural disaster mitigation science against destructive natural disaster mitigation. in the near future. We will present the details of natural disaster mitigation science.

  1. Turbulence Detection and Mitigation Element

    NASA Technical Reports Server (NTRS)

    Bogue, Rod

    2003-01-01

    This paper presents viewgraphs on turbulence detection and mitigation technologies in weather accident prevention. The topics include: 1) Organization; 2) Scope of Turbulence Effort; 3) Background; 4) Turbulence Detection and Mitigation Program Metrics; 5) Approach; 6) Turbulence Team Relationships; 7) WBS Structure; 8) Deliverables; 9) TDAM Changes; 10) FY-01 Results/Accomplishments; 11) Out-year Plans; and 12) Element Status.

  2. Tethers and debris mitigation

    NASA Astrophysics Data System (ADS)

    van der Heide, Erik Jan; Kruijff, Michiel

    2001-03-01

    In recent years, the use of tethers has been proposed for reduction of space debris either through momentum transfer or use of electrodynamic effects. Tethers have been shown to at least theoretically allow for quick, elegant and cost-effective deorbit of defunct satellites or spent stages. On the other hand, the large risk that tethers themselves may pose to other satellites in orbit has been recognized as well. The large collision area of tethers, combined with operational hazards and meteoroid risk may result in a large orbital exposure. For example, in 1997, the ESA/Dutch 35-km tether deployment of YES from TEAMSAT was inhibited after an analysis of the collision risk for the case the tether operation would fail. The question rises how these two points of view compare to eachother. This paper intends to highlight a representative selection of the proposed tether applications while taking into account the added risks caused by the tethers themselves. Typical applications from recent literature will be briefly described, such as an Ariane 502 spent stage re-entry from GTO and the concept of deboost of defunct satellites by interaction of a conductive tether with the Earth magnetic field. Mass savings of the tethered sytems versus conventional equivalents will be evaluated. Based on a crude risk analysis, involving elements such as mission complexity, dynamic stability, meteoroid risk and orbital life time, a general outline of limiting factors can be given for the various applications. Special attention is reserved for implementation of mechanisms that help reduce this tether risk, such as the DUtether (Tether Degradable by Ultraviolet), utilization of airdrag and solar pressure, the effect of residual current in bare tethers, tether retrieval etc. It is proposed how a net tether-induced mitigation can be compared to that of conventional alternatives, i.e. deboost by rocket engine or a completely passive approach. This comparison is put in the perspective of an

  3. Radar Ionospheric Impact Mitigation

    NASA Astrophysics Data System (ADS)

    Bishop, G.; Decker, D.; Baker, C.

    2006-12-01

    New ionospheric modeling technology is being developed to improve correction of ionospheric impacts on the performance of ground-based space-surveillance radars (SSRs) in near-real-time. These radars, which detect and track space objects, can experience significant target location errors due to ionospheric delay and refraction of the radar signals. Since these radars must detect and track targets essentially to the radar horizon, it is necessary to accurately model the ionosphere as the radar would observe it, down to the local horizon. To correct for spatial and temporal changes in the ionosphere the model must be able to update in near-real-time using ionospheric sensor data. Since many radars are in isolated locations, or may have requirements to operate autonomously, an additional required capability is to provide accurate ionospheric mitigation by exploiting only sensor data from the radar site. However, the model must also be able to update using additional data from other types of sensors that may be available. The original radar ionospheric mitigation approach employed the Bent climatological model. This 35-year-old technology is still the means employed in the many DoD SSRs today. One more recent approach used capabilities from the PRISM model. PRISM technology has today been surpassed by `assimilative models' which employ better physics and Kalman filtering techniques. These models are not necessarily tailored for SSR application which needs to optimize modeling of very small regions using only data from a single sensor, or very few. The goal is to develop and validate the performance of innovative and efficient ionospheric modeling approaches that are optimized for the small regions applicable to ground-based radar coverage (radius of ~2000 km at ionospheric altitudes) and somewhat beyond. These approaches must adapt a continuous modeling scheme in near-real-time to be consistent with all observational data that may become available, and degrade

  4. Translation readthrough mitigation.

    PubMed

    Arribere, Joshua A; Cenik, Elif S; Jain, Nimit; Hess, Gaelen T; Lee, Cameron H; Bassik, Michael C; Fire, Andrew Z

    2016-06-30

    A fraction of ribosomes engaged in translation will fail to terminate when reaching a stop codon, yielding nascent proteins inappropriately extended on their C termini. Although such extended proteins can interfere with normal cellular processes, known mechanisms of translational surveillance are insufficient to protect cells from potential dominant consequences. Here, through a combination of transgenics and CRISPR–Cas9 gene editing in Caenorhabditis elegans, we demonstrate a consistent ability of cells to block accumulation of C-terminal-extended proteins that result from failure to terminate at stop codons. Sequences encoded by the 3′ untranslated region (UTR) were sufficient to lower protein levels. Measurements of mRNA levels and translation suggested a co- or post-translational mechanism of action for these sequences in C. elegans. Similar mechanisms evidently operate in human cells, in which we observed a comparable tendency for translated human 3′ UTR sequences to reduce mature protein expression in tissue culture assays, including 3′ UTR sequences from the hypomorphic ‘Constant Spring’ haemoglobin stop codon variant. We suggest that 3′ UTRs may encode peptide sequences that destabilize the attached protein, providing mitigation of unwelcome and varied translation errors. PMID:27281202

  5. Mitigation analysis for Estonia

    SciTech Connect

    Martins, A.; Roos, J.; Pesur, A.

    1996-09-01

    The present report provides data on the mitigation analysis of Estonia. The results for energy, forest and agricultural sectors and macro-economic analysis are given. The Government of Estonia has identified the development of energy production as the main strategical means in the movement towards market economy. Now 99% of electricity generation and about 25% of heat production in Estonia is based on oil shale combustion. To increase the efficiency of oil shale-fired power plants and decrease CO{sub 2} emissions, the State Enterprise (SE) Eesti Energia (Estonian Energy) is planning to reconstruct these power plants and introduce the Circulating Fluidized Bed (CFB) combustion technology for oil shale burning to replace the Pulverized Combustion (PC). According to the Estonian Forest Policy, two general objectives are of importance: sustainability in forestry and efficiency in forest management. For the reduction of greenhouse gases (GHG) emissions from agriculture, it is necessary to increase the efficiency of production resource usage. The growth of the GDP in 1995 was 2.9% as a result of large-scale privatization activities in Estonia and re-introduction of the available, but unused production capacities with the help of foreign and domestic investments. It is assumed that the medium growth rate of GDP reaches 6% in 1998.

  6. Ultrasonic mitigation investigation

    SciTech Connect

    Hildebrand, B.P.; Shepard, C.L.

    1993-04-01

    The suggestion was made that the introduction of ultrasound into Tank 101-SY might serve to release the hydrogen bubbles trapped in the slurry. This would cause a continuous release of bubbles and thereby prevent the turnover phenomenon. Two major considerations were (1) the method for delivering the energy into the slurry and (2) the effective volume of action. In this study, we attached the former by designing and testing a liquid-filled waveguide and radiator, and the latter by making ultrasonic property measurements on synthetic waste. Our conclusion is that ultrasonic mitigation may not be feasible, primarily because of the very high attenuation (1000 to 50000 dB/m) factor to 10 to 30 kHz. Such a high attenuation would restrict the action volume to such a low value as to make the method impractical. Further investigations are recommended to identify the cause of this effect and determine if this same effect will be seen in real 101-SY waste.

  7. Antibiotic resistance in wild birds

    PubMed Central

    Bonnedahl, Jonas

    2014-01-01

    Wild birds have been postulated as sentinels, reservoirs, and potential spreaders of antibiotic resistance. Antibiotic-resistant bacteria have been isolated from a multitude of wild bird species. Several studies strongly indicate transmission of resistant bacteria from human rest products to wild birds. There is evidence suggesting that wild birds can spread resistant bacteria through migration and that resistant bacteria can be transmitted from birds to humans and vice versa. Through further studies of the spatial and temporal distribution of resistant bacteria in wild birds, we can better assess their role and thereby help to mitigate the increasing global problem of antibiotic resistance. PMID:24697355

  8. Environmental mitigation at hydroelectric projects

    SciTech Connect

    Sale, M.J.; Cada, G.F.; Chang, L.H.; Christensen, S.W.; Railsback, S.F. ); Francfort, J.E.; Rinehart, B.N.; Sommers, G.L. )

    1991-12-01

    Current environmental mitigation practices at nonfederal hydropower projects were analyzed. Information about instream flows, dissolved oxygen (DO) mitigation, and upstream and downstream fish passage facilities was obtained from project operators, regulatory and resource agencies, and literature reviews. Information provided by the operators includes the specific mitigation requirements imposed on each project, specific objectives or purposes of mitigation, mitigation measures chosen to meet the requirement, the kinds of post-project monitoring conducted, and the costs of mitigation. Costs are examined for each of the four mitigation methods, segmented by capital, study, operations and maintenance, and annual reporting costs. Major findings of the study include: the dominant role of the Instream Flow Incremental Methodology, in conjunction with professional judgment by agency biologists, to set instream flow requirements; reliance on spill flows for DO enhancement; and the widespread use of angled bar racks for downstream fish protection. All of these measures can have high costs and, with few exceptions, there are few data available from nonfederal hydropower projects with which to judge their effectiveness. 100 refs.

  9. Nuclear forces

    SciTech Connect

    Machleidt, R.

    2013-06-10

    These lectures present an introduction into the theory of nuclear forces. We focus mainly on the modern approach, in which the forces between nucleons emerge from low-energy QCD via chiral effective field theory.

  10. Albeni Falls Wildlife Mitigation Project : Annual Report of Mitigation Activities.

    SciTech Connect

    Entz, Ray D.

    2001-04-01

    The Albeni Falls Interagency Work Group was actively involved in implementing wildlife mitigation activities in 2000. The Work Group met each quarter to discuss management and budget issues affecting Albeni Falls wildlife mitigation. Members of the Work Group protected a total of 1,242 acres of wetland habitat in 2000. The total amount of wildlife habitat protected for Albeni Falls mitigation is approximately 4,190 acres (4,630 Habitat Units). Approximately 16% of the total wildlife habitat lost has been mitigated. Land management activities were limited in 2000 as protection opportunities took up most staff time. Administrative activities increased in 2000 as funding was more evenly distributed among Work Group members. As a result, implementation is expected to continue to increase in the coming year. Land management and monitoring and evaluation activities will increase in 2001 as site-specific management plans are completed and implemented.

  11. Labor Force

    ERIC Educational Resources Information Center

    Occupational Outlook Quarterly, 2012

    2012-01-01

    The labor force is the number of people ages 16 or older who are either working or looking for work. It does not include active-duty military personnel or the institutionalized population, such as prison inmates. Determining the size of the labor force is a way of determining how big the economy can get. The size of the labor force depends on two…

  12. Discrete fiber-reinforced polyurea systems for infrastructure strengthening and blast mitigation

    NASA Astrophysics Data System (ADS)

    Carey, Natalia L.

    The research presented in this dissertation focused on evaluating the effectiveness of various blast mitigation materials and coating technologies to be used for enhancing blast resistance of structural members. Mechanical properties and blast mitigation performance of different discrete fiber-reinforced polyurea (DFRP) systems were investigated through experimental and analytical work. Four technical papers discuss the research efforts conducted within this dissertation. The first paper examined the development and characterization of different DFRP systems for infrastructure strengthening and blast retrofit. The behavior of various systems which consisted of chopped E-glass fibers discretely integrated in with the polyurea matrix was evaluated through coupon tensile testing. The addition of glass fiber to a polymer coating provided improved stiffness and strength to the composite system while the polyurea base material provided ductility. The second paper evaluated the behavior of hybrid, plain, and steel fiber-reinforced concrete panels coated with various polyurea and DFRP systems under blast loading. Hybrid panels demonstrated higher blast mitigation performance compared to plain and steel fiber-reinforced concrete panels due to sacrificial hybrid layer. The addition of plain polyurea or DFRP systems on the tension side improved panel performance by containing fragmentation during a blast event. The third paper presents an analytical investigation conducted using the explicit finite element program LS-DYNA to model panel and coating response under blast loading. Several modeling solutions were undertaken and compared for concrete formulation. Modeling results were analyzed and compared to the experimental work to validate the conclusions. The final paper describes an internal equilibrium mechanics based model developed to predict the flexural capacity of reinforced concrete beams strengthened with various DFRP systems. The developed model was validated using

  13. Robust dynamic mitigation of instabilities

    SciTech Connect

    Kawata, S.; Karino, T.

    2015-04-15

    A dynamic mitigation mechanism for instability growth was proposed and discussed in the paper [S. Kawata, Phys. Plasmas 19, 024503 (2012)]. In the present paper, the robustness of the dynamic instability mitigation mechanism is discussed further. The results presented here show that the mechanism of the dynamic instability mitigation is rather robust against changes in the phase, the amplitude, and the wavelength of the wobbling perturbation applied. Generally, instability would emerge from the perturbation of the physical quantity. Normally, the perturbation phase is unknown so that the instability growth rate is discussed. However, if the perturbation phase is known, the instability growth can be controlled by a superposition of perturbations imposed actively: If the perturbation is induced by, for example, a driving beam axis oscillation or wobbling, the perturbation phase could be controlled, and the instability growth is mitigated by the superposition of the growing perturbations.

  14. Driving Forces of Mechanisms Regulating Oxacillin-Resistance Phenotypes of MRSA: Truly Oxacillin-Susceptible mecA-Positive Staphylococcus aureus Clinical Isolates also Exist.

    PubMed

    Pournaras, Spyros; Sabat, Artur J; Grundmann, Hajo; Hendrix, Ron; Tsakris, Athanasios; Friedrich, Alexander W

    2015-01-01

    As MRSA are considered Staphylococcus aureus isolates with oxacillin minimum inhibitory concentration (MIC) of ≥4 mg/L or harboring the mecA gene. However, the presence of mecA does not necessarily lead to oxacillin resistance and mecA gene-carrying isolates may have oxacillin MIC within the susceptible range (≥2 mg/L). During the last few years it has become apparent that oxacillin-susceptible (OS) mecA-positive S. aureus isolates (commonly called OS-MRSA) are rather commonly detected worldwide and may remain undiagnosed using phenotypic susceptibility testing methods. This review will summarize the current reports on OS-MRSA isolations and the underlying mechanisms regulating the expression of oxacillin resistance and also oxacillin susceptibility in mecA-positive S. aureus isolates. As MRSA commonly cause severe infections against which effective therapies are limited, understanding of these mechanisms could enable the identification of new targets for the treatment or reversion of the MRSA phenotype. PMID:25760336

  15. Global climate change and the mitigation challenge

    SciTech Connect

    Frank Princiotta

    2009-10-15

    Anthropogenic emissions of greenhouse gases, especially carbon dioxide (CO{sub 2}), have led to increasing atmospheric concentrations, very likely the primary cause of the 0.8{sup o}C warming the Earth has experienced since the Industrial Revolution. With industrial activity and population expected to increase for the rest of the century, large increases in greenhouse gas emissions are projected, with substantial global additional warming predicted. This paper examines forces driving CO{sub 2} emissions, a concise sector-by-sector summary of mitigation options, and research and development (R&D) priorities. To constrain warming to below approximately 2.5{sup o}C in 2100, the recent annual 3% CO{sub 2} emission growth rate needs to transform rapidly to an annual decrease rate of from 1 to 3% for decades. Furthermore, the current generation of energy generation and end-use technologies are capable of achieving less than half of the emission reduction needed for such a major mitigation program. New technologies will have to be developed and deployed at a rapid rate, especially for the key power generation and transportation sectors. Current energy technology research, development, demonstration, and deployment (RDD&D) programs fall far short of what is required. 20 refs., 18 figs., 4 tabs.

  16. Epidemiology today: Mitigating threats to an ecosystem.

    PubMed

    Kreiger, Nancy

    2016-01-01

    Ecosystems comprise all the living and non-living things in a particular area (e.g., rain forest, desert), which interact and maintain equilibrium. Loss of equilibrium (e.g., clear-cutting trees in a rain forest) can mean the decline of the ecosystem, unless it is able to adapt to the new circumstances. The term "knowledge ecosystem" describes an approach to managing knowledge in a particular field; the components of this system include the people, the technological skills and resources, and information or data. Epidemiology can be thought of as a knowledge ecosystem and, like ecological systems, its existence can be threatened, from both internal and external forces that may alter its equilibrium. This paper describes some threats to the epidemiology knowledge ecosystem, how these threats came about, and what responses we can make that may serve to mitigate those threats. PMID:27348106

  17. Tandem constructs to mitigate transgene persistence: tobacco as a model.

    PubMed

    Al-Ahmad, Hani; Galili, Shmuel; Gressel, Jonathan

    2004-03-01

    Some transgenic crops can introgress genes into other varieties of the crop, to related weeds or themselves remain as 'volunteer' weeds, potentially enhancing the invasiveness or weediness of the resulting offspring. The presently suggested mechanisms for transgene containment allow low frequency of gene release (leakage), requiring the mitigation of continued spread. Transgenic mitigation (TM), where a desired primary gene is tandemly coupled with mitigating genes that are positive or neutral to the crop but deleterious to hybrids and their progeny, was tested as a mechanism to mitigate transgene introgression. Dwarfism, which typically increases crop yield while decreasing the ability to compete, was used as a mitigator. A construct of a dominant ahasR (acetohydroxy acid synthase) gene conferring herbicide resistance in tandem with the semidominant mitigator dwarfing Delta gai (gibberellic acid-insensitive) gene was transformed into tobacco (Nicotiana tabacum). The integration and the phenotypic stability of the tandemly linked ahasR and Delta gai genomic inserts in later generations were confirmed by polymerase chain reaction. The hemizygous semidwarf imazapyr-resistant TM T1 (= BC1) transgenic plants were weak competitors when cocultivated with wild type segregants under greenhouse conditions and without using the herbicide. The competition was most intense at close spacings typical of weed offspring. Most dwarf plants interspersed with wild type died at 1-cm, > 70% at 2.5-cm and 45% at 5-cm spacing, and the dwarf survivors formed no flowers. At 10-cm spacing, where few TM plants died, only those TM plants growing at the periphery of the large cultivation containers formed flowers, after the wild type plants terminated growth. The highest reproductive TM fitness relative to the wild type was 17%. The results demonstrate the suppression of crop-weed hybrids when competing with wild type weeds, or such crops as volunteer weeds, in seasons when the selector

  18. 23 CFR 710.513 - Environmental mitigation.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... wetland mitigation sites and other mitigation banks is governed by 23 CFR part 777. (b) Environmental... 23 Highways 1 2010-04-01 2010-04-01 false Environmental mitigation. 710.513 Section 710.513...-WAY AND REAL ESTATE Property Acquisition Alternatives § 710.513 Environmental mitigation. (a)...

  19. 23 CFR 710.513 - Environmental mitigation.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... wetland mitigation sites and other mitigation banks is governed by 23 CFR part 777. (b) Environmental... 23 Highways 1 2011-04-01 2011-04-01 false Environmental mitigation. 710.513 Section 710.513...-WAY AND REAL ESTATE Property Acquisition Alternatives § 710.513 Environmental mitigation. (a)...

  20. 23 CFR 710.513 - Environmental mitigation.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... wetland mitigation sites and other mitigation banks is governed by 23 CFR part 777. (b) Environmental... 23 Highways 1 2013-04-01 2013-04-01 false Environmental mitigation. 710.513 Section 710.513...-WAY AND REAL ESTATE Property Acquisition Alternatives § 710.513 Environmental mitigation. (a)...

  1. 23 CFR 710.513 - Environmental mitigation.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... wetland mitigation sites and other mitigation banks is governed by 23 CFR part 777. (b) Environmental... 23 Highways 1 2012-04-01 2012-04-01 false Environmental mitigation. 710.513 Section 710.513...-WAY AND REAL ESTATE Property Acquisition Alternatives § 710.513 Environmental mitigation. (a)...

  2. NASA's Research in Aircraft Vulnerability Mitigation

    NASA Technical Reports Server (NTRS)

    Allen, Cheryl L.

    2005-01-01

    Since its inception in 1958, the National Aeronautics and Space Administration s (NASA) role in civil aeronautics has been to develop high-risk, high-payoff technologies to meet critical national aviation challenges. Following the events of Sept. 11, 2001, NASA recognized that it now shared the responsibility for improving homeland security. The NASA Strategic Plan was modified to include requirements to enable a more secure air transportation system by investing in technologies and collaborating with other agencies, industry, and academia. NASA is conducting research to develop and advance innovative and commercially viable technologies that will reduce the vulnerability of aircraft to threats or hostile actions, and identify and inform users of potential vulnerabilities in a timely manner. Presented in this paper are research plans and preliminary status for mitigating the effects of damage due to direct attacks on civil transport aircraft. The NASA approach to mitigation includes: preventing loss of an aircraft due to a hit from man-portable air defense systems; developing fuel system technologies that prevent or minimize in-flight vulnerability to small arms or other projectiles; providing protection from electromagnetic energy attacks by detecting directed energy threats to aircraft and on/off-board systems; and minimizing the damage due to high-energy attacks (explosions and fire) by developing advanced lightweight, damage-resistant composites and structural concepts. An approach to preventing aircraft from being used as weapons of mass destruction will also be discussed.

  3. Industry initiatives in impact mitigation

    SciTech Connect

    Metz, W.C.

    1982-08-01

    The author concludes that mitigation is the focus of conflicting opinions regarding responsibility, strategy, and effort. There are no hard, fast, or tried and true rules for company involvement in mitigation efforts. Each mitigation effort must be tailored and negotiated to match the unique characteristics of individual projects and circumstances of specific locales. Companies must assume financial responsibility for the temporary impacts and area needs created by their projects. They must also offer financial and technical assistance to impact areas, not just the host political jurisdiction, when local, state, federal, and special fund sources of revenue or technical assistance are not available or insufficient. But, local, state, and federal governments must also recognize their responsibilities and make adjustments in tax jurisdiction boundaries and disbursement formulas so that impacted areas are properly defined and receive an adequate share of lease, royalty, severance tax, permit fee, special use and service charges, and sales tax payments. Laws need to allow innovative uses of tax pre-payments, housing mortgage bonds, changeable debt and bounding limits, industrial loans with delayed prepayment, and revised revenue assistance formulas. Enabling legislation is required in most states to allow impact areas to negotiate the mitigation efforts. A review of 7 types of mitigation effort is presented: transportation; housing; public utilities; health, public safety and recreation; miscellaneous; and company-community interaction. (PBS)

  4. Resistive Exercise Device

    NASA Technical Reports Server (NTRS)

    Smith, Damon C. (Inventor)

    2005-01-01

    An exercise device 10 is particularly well suited for use in low gravity environments, and includes a frame 12 with plurality of resistance elements 30,82 supported in parallel on the frame. A load transfer member 20 is moveable relative to the frame for transferring the applied force to the free end of each captured resistance element. Load selection template 14 is removably secured both to the load transfer member, and a plurality of capture mechanisms engage the free end of corresponding resistance elements. The force applying mechanism 53 may be a handle, harness or other user interface for applying a force to move the load transfer member.

  5. One Force

    NASA Astrophysics Data System (ADS)

    Kotas, Ronald R.

    2002-04-01

    There is only one entity that can extend force and couple through space; and it should be apparent that Electromagnetism is that entity. In the cases of the nuclear strong force and the nuclear weak force, this is the same fundamental Electromagnetism manifesting itself in two different ways in the nucleus. It remains the same basic Electromagnetism. On the other hand, General Relativity fails to produce force at a distance, fails the Cavendish experiment, and does not allow an apple to fall to the ground. The result shows there is only Electromagnetism that functions through physical nature providing gravity, actions in the nucleus, as well as all other physical actions universally, including Gravity and Gravitation. There are many direct proofs of this, the same proofs as in NUCLEAR QUANTUM GRAVITATION. In contrast, General Relativity plainly relies on fallacy abstract and incoherent proofs; proofs which have now been mostly disproved. In the past it was deemed necessary by some to have an "ether" to propagate Electromagnetic waves. The fallacy concept of time space needs "space distortions" in order to cause gravity. However, Electromagnetic gravity does not have this problem. Clearly there is only ONE FORCE that causes Gravity, Electromagnetism, the Nuclear Strong Force, and the Nuclear Weak Force, and that ONE FORCE is Electromagnetism.

  6. Labor Force

    ERIC Educational Resources Information Center

    Occupational Outlook Quarterly, 2010

    2010-01-01

    The labor force is the number of people aged 16 or older who are either working or looking for work. It does not include active-duty military personnel or institutionalized people, such as prison inmates. Quantifying this total supply of labor is a way of determining how big the economy can get. Labor force participation rates vary significantly…

  7. Mitigation of Helical Vortex Separation of a 5:1 Prolate Spheroid at an Angle of Attack

    NASA Astrophysics Data System (ADS)

    Schulmeister, James; Triantafyllou, Michael

    2015-11-01

    Ocean and air vehicle maneuvering performance is determined by the balance between a vehicle's capacity to exert large lateral forces and its fluid dynamic resistance. The flow past a 5:1 prolate spheroid at an angle of attack is representative of many maneuvering hull forms where cross-flow separation creates helical vortices that dramatically increase drag during maneuvers. We investigate a shape modification to a 5:1 prolate spheroid that streamlines the spheroid in the cross-flow direction in order to mitigate vortex separation. We conduct a series of experiments with models towed at angles of attack between 5 and 30 degrees at a Reynolds number by length equal to 100,000. Reconstructions of the helical vortex separation from cross-flow particle image velocimetry measurements show that modest streamlining significantly reduces the size and circulation of separated vortices, indicating drag reduction.

  8. A course in disaster mitigation.

    PubMed

    Bundy, Sarah J

    2016-01-01

    While endeavors are underway within the emergency management discipline to develop a unique body of foundational knowledge, widespread acknowledgement and agreement within the emergency management scholarly community of the existence of theoretical foundations and the consistent incorporation of these elements into emergency management research and teaching are still lacking. This article offers an outline of a US-based undergraduate course in mitigation theory and practice that is based on a synthesis of the academic literature related to disaster mitigation as a means to advance the discourse on foundational knowledge and curriculum development. The course outline proposes a set of concepts, theories, propositions, and empirical data that would arguably be fundamental for students in gaining a comprehensive understanding of mitigation in the United States and suggests how that information can be organized and presented in a meaningful way. PMID:26963230

  9. Simulation of wave mitigation by coastal vegetation using smoothed particle hydrodynamics method

    NASA Astrophysics Data System (ADS)

    Iryanto; Gunawan, P. H.

    2016-02-01

    Vegetation in coastal area lead to wave mitigation has been studied by some researchers recently. The effect of vegetation forest in coastal area is minimizing the negative impact of wave propagation. In order to describe the effect of vegetation resistance into the water flow, the modified model of framework smoothed hydrodynamics particle has been constructed. In the Lagrangian framework, the Darcy, Manning, and laminar viscosity resistances are added. The effect of each resistances is given in some results of numerical simulations. Simulation of wave mitigation on sloping beach is also given.

  10. Force sensor

    DOEpatents

    Grahn, Allen R.

    1993-01-01

    A force sensor and related method for determining force components. The force sensor includes a deformable medium having a contact surface against which a force can be applied, a signal generator for generating signals that travel through the deformable medium to the contact surface, a signal receptor for receiving the signal reflected from the contact surface, a generation controller, a reception controller, and a force determination apparatus. The signal generator has one or more signal generation regions for generating the signals. The generation controller selects and activates the signal generation regions. The signal receptor has one or more signal reception regions for receiving signals and for generating detections signals in response thereto. The reception controller selects signal reception regions and detects the detection signals. The force determination apparatus measures signal transit time by timing activation and detection and, optionally, determines force components for selected cross-field intersections. The timer which times by activation and detection can be any means for measuring signal transit time. A cross-field intersection is defined by the overlap of a signal generation region and a signal reception region.

  11. Force sensor

    DOEpatents

    Grahn, A.R.

    1993-05-11

    A force sensor and related method for determining force components is described. The force sensor includes a deformable medium having a contact surface against which a force can be applied, a signal generator for generating signals that travel through the deformable medium to the contact surface, a signal receptor for receiving the signal reflected from the contact surface, a generation controller, a reception controller, and a force determination apparatus. The signal generator has one or more signal generation regions for generating the signals. The generation controller selects and activates the signal generation regions. The signal receptor has one or more signal reception regions for receiving signals and for generating detections signals in response thereto. The reception controller selects signal reception regions and detects the detection signals. The force determination apparatus measures signal transit time by timing activation and detection and, optionally, determines force components for selected cross-field intersections. The timer which times by activation and detection can be any means for measuring signal transit time. A cross-field intersection is defined by the overlap of a signal generation region and a signal reception region.

  12. The Common Forces: Conservative or Nonconservative?

    ERIC Educational Resources Information Center

    Keeports, David

    2006-01-01

    Of the forces commonly encountered when solving problems in Newtonian mechanics, introductory texts usually limit illustrations of the definitions of conservative and nonconservative forces to gravity, spring forces, kinetic friction and fluid resistance. However, at the expense of very little class time, the question of whether each of the common…

  13. Remote Sensing Technologies Mitigate Drought

    NASA Technical Reports Server (NTRS)

    2015-01-01

    Ames Research Center has partnered with the California Department of Water Resources to develop satellite-based technologies to mitigate drought conditions. One project aims to help water managers adjust their irrigation to match the biological needs of each crop, and another involves monitoring areas where land is fallow so emergency relief can more quickly aid affected communities.

  14. RADON MITIGATION STUDIES: NASHVILLE DEMONSTRATION

    EPA Science Inventory

    The report gives results of an EPA radon mitigation demonstration project involving 14 houses in the Nashville, TN, area with indoor radon levels of 5.6-47.6 pCi/L, using a variety of techniques, designed to be the most cost effective methods possible to implement, and yet adequa...

  15. Lunar Dust: Characterization and Mitigation

    NASA Technical Reports Server (NTRS)

    Hyatt. Mark J.; Feighery, John

    2007-01-01

    Lunar dust is a ubiquitous phenomenon which must be explicitly addressed during upcoming human lunar exploration missions. Near term plans to revisit the moon as a stepping stone for further exploration of Mars, and beyond, places a primary emphasis on characterization and mitigation of lunar dust. Comprised of regolith particles ranging in size from tens of nanometers to microns, lunar dust is a manifestation of the complex interaction of the lunar soil with multiple mechanical, electrical, and gravitational effects. The environmental and anthropogenic factors effecting the perturbation, transport, and deposition of lunar dust must be studied in order to mitigate it's potentially harmful effects on exploration systems. The same hold true for assessing the risk it may pose for toxicological health problems if inhaled. This paper presents the current perspective and implementation of dust knowledge management and integration, and mitigation technology development activities within NASA's Exploration Technology Development Program. This work is presented within the context of the Constellation Program's Integrated Lunar Dust Management Strategy. This work further outlines the scientific basis for lunar dust behavior, it's characteristics and potential effects, and surveys several potential strategies for its control and mitigation both for lunar surface operations and within the working volumes of a lunar outpost. The paper also presents a perspective on lessons learned from Apollo and forensics engineering studies of Apollo hardware.

  16. Greenhouse gas mitigation in agriculture.

    PubMed

    Smith, Pete; Martino, Daniel; Cai, Zucong; Gwary, Daniel; Janzen, Henry; Kumar, Pushpam; McCarl, Bruce; Ogle, Stephen; O'Mara, Frank; Rice, Charles; Scholes, Bob; Sirotenko, Oleg; Howden, Mark; McAllister, Tim; Pan, Genxing; Romanenkov, Vladimir; Schneider, Uwe; Towprayoon, Sirintornthep; Wattenbach, Martin; Smith, Jo

    2008-02-27

    Agricultural lands occupy 37% of the earth's land surface. Agriculture accounts for 52 and 84% of global anthropogenic methane and nitrous oxide emissions. Agricultural soils may also act as a sink or source for CO2, but the net flux is small. Many agricultural practices can potentially mitigate greenhouse gas (GHG) emissions, the most prominent of which are improved cropland and grazing land management and restoration of degraded lands and cultivated organic soils. Lower, but still significant mitigation potential is provided by water and rice management, set-aside, land use change and agroforestry, livestock management and manure management. The global technical mitigation potential from agriculture (excluding fossil fuel offsets from biomass) by 2030, considering all gases, is estimated to be approximately 5500-6000Mt CO2-eq.yr-1, with economic potentials of approximately 1500-1600, 2500-2700 and 4000-4300Mt CO2-eq.yr-1 at carbon prices of up to 20, up to 50 and up to 100 US$ t CO2-eq.-1, respectively. In addition, GHG emissions could be reduced by substitution of fossil fuels for energy production by agricultural feedstocks (e.g. crop residues, dung and dedicated energy crops). The economic mitigation potential of biomass energy from agriculture is estimated to be 640, 2240 and 16 000Mt CO2-eq.yr-1 at 0-20, 0-50 and 0-100 US$ t CO2-eq.-1, respectively. PMID:17827109

  17. Space debris detection and mitigation

    SciTech Connect

    Allahdadi, F.

    1993-01-01

    Space debris is defined as all useless man-made objects in space. This conference covers the following areas: debris detection, tracking, and surveillance; orbital debris analytical modeling; debris environment and safety issues; and orbital debris mitigation. Separate abstracts were prepared for 26 papers in this conference.

  18. Annual report on contractor work force restructuring, fiscal year 1997

    SciTech Connect

    1998-03-01

    This report summarizes work force restructuring and community transition activities at all sites. It outlines work force restructuring activity for FY 1997, changing separation patterns, cost savings and separation costs, program assessment, activities to mitigate restructuring impacts, community transition activities, status of displaced workers, lessons learned, and emerging issues in worker and community transition. Work force restructuring and community transition activities for defense nuclear sites are summarized, as are work force restructuring activities at non-defense sites.

  19. Climate adaptation as mitigation: the case of agricultural investments

    NASA Astrophysics Data System (ADS)

    Lobell, David B.; Baldos, Uris Lantz C.; Hertel, Thomas W.

    2013-03-01

    with respect to land rents, and the elasticity of substitution between land and non-land inputs. For assessing the mitigation costs, the elasticity of productivity with respect to investments in research and development is also very important. Overall, this study finds that broad-based efforts to adapt agriculture to climate change have mitigation co-benefits that, even when forced to shoulder the entire expense of adaptation, are inexpensive relative to many activities whose main purpose is mitigation. These results therefore challenge the current approach of most climate financing portfolios, which support adaptation from funds completely separate from—and often much smaller than—mitigation ones.

  20. Lunar Dust Mitigation Technology Development

    NASA Technical Reports Server (NTRS)

    Hyatt, Mark J.; Deluane, Paul B.

    2008-01-01

    NASA s plans for implementing the Vision for Space Exploration include returning to the moon as a stepping stone for further exploration of Mars, and beyond. Dust on the lunar surface has a ubiquitous presence which must be explicitly addressed during upcoming human lunar exploration missions. While the operational challenges attributable to dust during the Apollo missions did not prove critical, the comparatively long duration of impending missions presents a different challenge. Near term plans to revisit the moon places a primary emphasis on characterization and mitigation of lunar dust. Comprised of regolith particles ranging in size from tens of nanometers to microns, lunar dust is a manifestation of the complex interaction of the lunar soil with multiple mechanical, electrical, and gravitational effects. The environmental and anthropogenic factors effecting the perturbation, transport, and deposition of lunar dust must be studied in order to mitigate it s potentially harmful effects on exploration systems. This paper presents the current perspective and implementation of dust knowledge management and integration, and mitigation technology development activities within NASA s Exploration Technology Development Program. This work is presented within the context of the Constellation Program s Integrated Lunar Dust Management Strategy. The Lunar Dust Mitigation Technology Development project has been implemented within the ETDP. Project scope and plans will be presented, along with a a perspective on lessons learned from Apollo and forensics engineering studies of Apollo hardware. This paper further outlines the scientific basis for lunar dust behavior, it s characteristics and potential effects, and surveys several potential strategies for its control and mitigation both for lunar surface operations and within the working volumes of a lunar outpost.

  1. Climate mitigation and the future of tropical landscapes

    PubMed Central

    Thomson, Allison M.; Calvin, Katherine V.; Chini, Louise P.; Hurtt, George; Edmonds, James A.; Bond-Lamberty, Ben; Frolking, Steve; Wise, Marshall A.; Janetos, Anthony C.

    2010-01-01

    Land-use change to meet 21st-century demands for food, fuel, and fiber will depend on many interactive factors, including global policies limiting anthropogenic climate change and realized improvements in agricultural productivity. Climate-change mitigation policies will alter the decision-making environment for land management, and changes in agricultural productivity will influence cultivated land expansion. We explore to what extent future increases in agricultural productivity might offset conversion of tropical forest lands to crop lands under a climate mitigation policy and a contrasting no-policy scenario in a global integrated assessment model. The Global Change Assessment Model is applied here to simulate a mitigation policy that stabilizes radiative forcing at 4.5 W m−2 (approximately 526 ppm CO2) in the year 2100 by introducing a price for all greenhouse gas emissions, including those from land use. These scenarios are simulated with several cases of future agricultural productivity growth rates and the results downscaled to produce gridded maps of potential land-use change. We find that tropical forests are preserved near their present-day extent, and bioenergy crops emerge as an effective mitigation option, only in cases in which a climate mitigation policy that includes an economic price for land-use emissions is in place, and in which agricultural productivity growth continues throughout the century. We find that idealized land-use emissions price assumptions are most effective at limiting deforestation, even when cropland area must increase to meet future food demand. These findings emphasize the importance of accounting for feedbacks from land-use change emissions in global climate change mitigation strategies. PMID:20921413

  2. [Rodenticide resistance and consequences].

    PubMed

    Esther, A; Endepols, S; Freise, J; Klemann, N; Runge, M; Pelz, H-J

    2014-05-01

    Resistance to anticoagulant rodenticides, such as warfarin was first described in 1958. Polymorphisms in the vitamin K epoxide reductase complex subunit 1 (VKORC1) gene and respective substitutions of amino acids in the VKOR enzyme are the major cause for rodenticide resistance. Resistant Norway rats in Germany are characterized by the Tyr139Cys genotype, which is spread throughout the northwest of the country. Resistant house mice with the VKOR variants Tyr139Cys, Leu128Ser and Arg12Trp/Ala26Ser/Ala48Thr/Arg61Leu (spretus type) are distributed over a number of locations in Germany. Resistance can reduce management attempts with consequences for stored product protection, hygiene and animal health. Anticoagulants of the first generation (warfarin, chlorophacinone, coumatetralyl) as well as bromadiolone and difenacoum are not an option for the control of resistant Norway rats. The same applies for house mice whereby the tolerance to compounds can be different between local incidences. Due to the higher toxicity and tendency to persist, the most potent anticoagulant rodenticides brodifacoum, flocoumafen and difethialone should be applied but only where resistance is known. In other cases less toxic anticoagulants should be preferred for rodent management in order to mitigate environmental risks. Resistance effects of further VKOR polymorphisms and their combinations, the spread of resistant rats and conditions supporting and reducing resistance should be investigated in order to improve resistance management strategies. PMID:24781908

  3. Vacuum force

    NASA Astrophysics Data System (ADS)

    Han, Yongquan

    2015-03-01

    To study on vacuum force, we must clear what is vacuum, vacuum is a space do not have any air and also ray. There is not exist an absolute the vacuum of space. The vacuum of space is relative, so that the vacuum force is relative. There is a certain that vacuum vacuum space exists. In fact, the vacuum space is relative, if the two spaces compared to the existence of relative vacuum, there must exist a vacuum force, and the direction of the vacuum force point to the vacuum region. Any object rotates and radiates. Rotate bend radiate- centripetal, gravity produced, relative gravity; non gravity is the vacuum force. Gravity is centripetal, is a trend that the objects who attracted wants to Centripetal, or have been do Centripetal movement. Any object moves, so gravity makes the object curve movement, that is to say, the radiation range curve movement must be in the gravitational objects, gravity must be existed in non vacuum region, and make the object who is in the region of do curve movement (for example: The earth moves around the sun), or final attracted in the form gravitational objects, and keep relatively static with attract object. (for example: objects on the earth moves but can't reach the first cosmic speed).

  4. Mitigation of Lunar Dust Adhesion by Surface Treatment

    NASA Astrophysics Data System (ADS)

    Dove, A.; Wang, X.; Robertson, S. H.; Horanyi, M.; Devaud, J.; Crowder, M.; Lawitzke, A.

    2009-12-01

    Dust has been recognized as one of the greatest hazards in continued lunar exploration. Thus, it is crucial to develop dust mitigation techniques that will minimize both the damages done to hardware and the dangers posed to humans working on the Moon. Passive mitigation techniques, which modify the surface of a material prior to dust exposure, will aid in repelling dust or reducing adhesion for easier dust removal. Our experiments use various surfaces (black Kapton (polymide), quartz, and silicon) that have been treated to have low surface energies by a Ball Aerospace and Technologies Corp. proprietary surface treatment technique. We use a centrifugal force detachment method to measure the total adhesive force acting between < 25 µm JSC-1 lunar simulant grains and these surfaces, both untreated and treated, in vacuum. Results indicate that the treated surfaces show significant improvement; dust is removed from treated black Kapton with about 4% of the force required for untreated black Kapton, while treated quartz and silicon show about a 50% reduction in force. Further tests will be conducted on additional surfaces, such as stainless steel and polycarbonate, and with different size fractions of JSC-1 in order to evaluate the role of dust grain size on adhesion. Because the Moon’s surface is directly exposed to solar UV radiation, we will also measure adhesion on surfaces that have previously been UV-irradiated.

  5. 7 CFR 1794.17 - Mitigation.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... § 1794.17 Mitigation. (a) General. In addition to complying with the requirements of 40 CFR 1502.14(f... (FONSI) and the Record of Decision (ROD). (b) Water and waste program. (1) Mitigation measures...

  6. 7 CFR 1794.17 - Mitigation.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... § 1794.17 Mitigation. (a) General. In addition to complying with the requirements of 40 CFR 1502.14(f... (FONSI) and the Record of Decision (ROD). (b) Water and waste program. (1) Mitigation measures...

  7. 7 CFR 1794.17 - Mitigation.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... § 1794.17 Mitigation. (a) General. In addition to complying with the requirements of 40 CFR 1502.14(f... (FONSI) and the Record of Decision (ROD). (b) Water and waste program. (1) Mitigation measures...

  8. 7 CFR 1794.17 - Mitigation.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... § 1794.17 Mitigation. (a) General. In addition to complying with the requirements of 40 CFR 1502.14(f... (FONSI) and the Record of Decision (ROD). (b) Water and waste program. (1) Mitigation measures...

  9. Normal incidence collector for LPP sources with integrated debris mitigation

    NASA Astrophysics Data System (ADS)

    Giovannini, Andrea Z.; Dieterich, Franz; Henderson, Ian; Chokani, Ndaona; Abhari, Reza S.

    2010-04-01

    The leading candidate for the manufacture of next generation semi-conductor devices is extreme ultraviolet lithography, with laser-produced plasmas as a candidate 13.5nm light source. A primary challenge for continuous operation is elimination of the debris load on the collector, without compromising the radiation intensity at the intermediate focus. A novel combination of thermal management and debris mitigation is developed in order to reduce the deformation and degradation of collector optics. This patent-pending novel debris mitigation technique enables the continuous operation of the source. The paper shows atomic force microscope measurements of the collector surface deposition. The debris mitigation system run at 50% design operating condition gives 90% debris mitigation effectiveness. The average temperature of the cooled collector is 36.5°C at the design point, with a peak-to-peak difference of 0.8°C. The collector geometry, after being adapted to compensate the thermal deformation, yields a spot size of 30μm at IF. Computational simulations, using ETH's multi-scale computational tools, complement the presented experimental results.

  10. Climate mitigation and the future of tropical landscapes

    SciTech Connect

    Thomson, Allison M.; Calvin, Katherine V.; Chini, Louise Parsons; Hurtt, George; Edmonds, James A.; Bond-Lamberty, Benjamin; Frolking, Steve; Wise, Marshall A.; Janetos, Anthony C.

    2010-11-16

    Land use change to meet 21st Century demands for food, fuel, and fiber will occur in the context of both a changing climate as well as societal efforts to mitigate climate change. This changing natural and human environment will have large consequences for forest resources, terrestrial carbon storage and emissions, and food and energy crop production over the next century. Any climate change mitigation policies enacted will change the environment under which land-use decisions are made and alter global land use change patterns. Here we use the GCAM integrated assessment model to explore how climate mitigation policies that achieve a climate stabilization at 4.5 W m-2 radiative forcing in 2100 and value carbon in terrestrial ecosystems interact with future agricultural productivity and food and energy demands to influence land use in the tropics. The regional land use results are downscaled from GCAM regions to produce gridded maps of tropical land use change. We find that tropical forests are preserved only in cases where a climate mitigation policy that values terrestrial carbon is in place, and crop productivity growth continues throughout the century. Crop productivity growth is also necessary to avoid large scale deforestation globally and enable the production of bioenergy crops. The terrestrial carbon pricing assumptions in GCAM are effective at avoiding deforestation even when cropland must expand to meet future food demand.

  11. Planning Tools For Seismic Risk Mitigation. Rules And Applications

    SciTech Connect

    De Paoli, Rosa Grazia

    2008-07-08

    Recently, Italian urban planning research in the field of seismic risk mitigation are renewing. In particular, it promotes strategies that integrate urban rehabilitation and aseismic objectives, and also politicizes that are directed to revitalizes urban systems, coupling physical renewal and socio-economic development.In Italy the first law concerning planning for seismic mitigation dates back 1974, the law n. 64 'Regulation for buildings with particular rules for the seismic areas' where the rules for buildings in seismic areas concerning also the local hazard. This law, in fact, forced the municipalities to acquire, during the formation of the plans, a preventive opinion of compatibility between planning conditions and geomorphology conditions of the territory. From this date the conviction that the seismic risk must be considered inside the territorial planning especially in terms of strategies of mitigation has been strengthened.The town planners have started to take an interest in seismic risk in the [80]s when the Irpinia's earthquake took place. The researches developed after this earthquake have established that the principal cause of the collapse of buildings are due to from the wrong location of urban settlements (on slopes or crowns) After Irpinia's earthquake the first researches on seismic risk mitigation, in particular on the aspects related to the hazards and to the urban vulnerability were made.

  12. Ice Detection and Mitigation Device

    NASA Technical Reports Server (NTRS)

    Gambino, Richard J. (Inventor); Gouldstone, Christopher (Inventor); Gutleber, Jonathan (Inventor); Hubble, David (Inventor); Trelewicz, Jason (Inventor)

    2016-01-01

    A method for deicing an aerostructure includes driving a sensing current through a heater element coated to an aerostructure, the heater element having a resistance that is temperature dependent. A resistance of the heater element is monitored. It is determined whether there is icing at the heater element using the monitored resistance of the heater element. A melting current is driven through the heater element when it is determined that there is icing at the heater element.

  13. ITER Disruption Mitigation System Design

    NASA Astrophysics Data System (ADS)

    Rasmussen, David; Lyttle, M. S.; Baylor, L. R.; Carmichael, J. R.; Caughman, J. B. O.; Combs, S. K.; Ericson, N. M.; Bull-Ezell, N. D.; Fehling, D. T.; Fisher, P. W.; Foust, C. R.; Ha, T.; Meitner, S. J.; Nycz, A.; Shoulders, J. M.; Smith, S. F.; Warmack, R. J.; Coburn, J. D.; Gebhart, T. E.; Fisher, J. T.; Reed, J. R.; Younkin, T. R.

    2015-11-01

    The disruption mitigation system for ITER is under design and will require injection of up to 10 kPa-m3 of deuterium, helium, neon, or argon material for thermal mitigation and up to 100 kPa-m3 of material for suppression of runaway electrons. A hybrid unit compatible with the ITER nuclear, thermal and magnetic field environment is being developed. The unit incorporates a fast gas valve for massive gas injection (MGI) and a shattered pellet injector (SPI) to inject a massive spray of small particles, and can be operated as an SPI with a frozen pellet or an MGI without a pellet. Three ITER upper port locations will have three SPI/MGI units with a common delivery tube. One equatorial port location has space for sixteen similar SPI/MGI units. Supported by US DOE under DE-AC05-00OR22725.

  14. Mitigating hyperventilation during cardiopulmonary resuscitation.

    PubMed

    Nikolla, Dhimitri; Lewandowski, Tyler; Carlson, Jestin

    2016-03-01

    Although multiple airway management and ventilation strategies have been proposed during cardiac arrest, the ideal strategy is unknown. Current strategies call for advanced airways, such as endotracheal intubation and supraglottic airways. These may facilitate hyperventilation which is known to adversely affect cardiopulmonary physiology. We provide a summary of conceptual models linking hyperventilation to patient outcomes and identify methods for mitigating hyperventilation during cardiac arrest. PMID:26740418

  15. 7 CFR 1794.17 - Mitigation.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 12 2014-01-01 2013-01-01 true Mitigation. 1794.17 Section 1794.17 Agriculture... § 1794.17 Mitigation. (a) General. In addition to complying with the requirements of 40 CFR 1502.14(f... (FONSI) and the Record of Decision (ROD). (b) Water and waste program. (1) Mitigation measures...

  16. 43 CFR 10005.8 - Mitigation obligations.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Mitigation obligations. 10005.8 Section 10005.8 Public Lands: Interior Regulations Relating to Public Lands (Continued) UTAH RECLAMATION MITIGATION AND CONSERVATION COMMISSION POLICIES AND PROCEDURES FOR DEVELOPING AND IMPLEMENTING THE COMMISSION'S MITIGATION AND CONSERVATION PLAN §...

  17. 7 CFR 652.39 - Mitigating factors.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 6 2010-01-01 2010-01-01 false Mitigating factors. 652.39 Section 652.39 Agriculture... AGRICULTURE SUPPORT ACTIVITIES TECHNICAL SERVICE PROVIDER ASSISTANCE Decertification § 652.39 Mitigating..., the deciding official will take into consideration any mitigating factors. Examples of...

  18. 34 CFR 81.33 - Mitigating circumstances.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 34 Education 1 2010-07-01 2010-07-01 false Mitigating circumstances. 81.33 Section 81.33 Education... for Recovery of Funds § 81.33 Mitigating circumstances. (a) A recipient that is a State or local... funds is not required to return any amount that is attributable to the mitigating...

  19. 23 CFR 710.513 - Environmental mitigation.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... wetland mitigation sites and other mitigation banks is governed by 23 CFR part 777. (b) Environmental...-WAY AND REAL ESTATE Property Acquisition Alternatives § 710.513 Environmental mitigation. (a) The... financial assistance. This includes real property acquired for a wetland bank, or other...

  20. Mitigation alternatives for L Lake

    SciTech Connect

    Moore, D.B.

    1988-11-03

    The current condition of L Lake/Steel Creek was summarized in a report to SCDHEC in June 1988 which reported that the L Lake and Steel Creek ecosystems were adequately developing towards balanced biological communities. If mitigation for L Lake inputs, specifically temperature and nutrients, are required, several viable alternatives are available. A report prepared by Spencer in 1986 discusses the various options available for cooling L-Reactor discharges. In effect, a small cooling tower is the only realistic solution to reducing effluent temperatures. Nutrient mitigation can take several approaches including upstream sewage treatment, hypolimnetic withdrawal, dilution of input water by Par Pond water, precipitation of nutrients, and sediment oxidation. None of these systems would influence the thermal regime, but would significantly reduce nutrient input into the system. One beneficial use of L-Lake thermal effluents is algaculture, the production of useful algae. A document prepared in 1988 concludes that algaculture is a technically and economically feasible mitigation alternative for L Lake and could allow L Lake to be handled under Section 318 of the Clean Water Act.

  1. Near-Term Climate Mitigation by Short-Lived Forcers

    SciTech Connect

    Smith, Steven J.; Mizrahi, Andrew H.

    2013-08-12

    Emissions reductions focused on anthropogenic climate forcing agents with relatively short atmospheric lifetimes such as methane (CH4) and black carbon (BC) have been suggested as a strategy to reduce the rate of climate change over the next several decades. We find that reductions of methane and BC would likely have only a modest impact on near-term climate warming. Even with maximally feasible reductions phased in from 2015 to 2035, global mean temperatures in 2050 are reduced by 0.16 °C, with an uncertainty range of 0.04-0.36°C, with the high end of this range only possible if total historical aerosol forcing is small. More realistic mitigation scenarios would likely provide a smaller climate benefit. The climate benefits from targeted reductions in short-lived forcing agents are smaller than previously estimated and are not substantially different in magnitude from the benefits due to a comprehensive climate policy.

  2. Forced oscillations with linear and nonlinear damping

    NASA Astrophysics Data System (ADS)

    Li, Aijun; Ma, Li; Keene, David; Klingel, Joshua; Payne, Marvin; Wang, Xiao-jun

    2016-01-01

    A general solution is derived for the differential equations of forced oscillatory motion with both linear damping ( ˜v ) and nonlinear damping ( ˜v2 ). Experiments with forced oscillators are performed using a flat metal plate with a drag force due to eddy currents and a flat piece of stiffened cardboard with a drag force due to air resistance serving as the linear and nonlinear damping, respectively. Resonance of forced oscillations for different damping forces and quality factors is demonstrated. The experimental measurements and theoretical calculations are in good agreement, and damping constants are determined.

  3. A web-based tool for ranking landslide mitigation measures

    NASA Astrophysics Data System (ADS)

    Lacasse, S.; Vaciago, G.; Choi, Y. J.; Kalsnes, B.

    2012-04-01

    As part of the research done in the European project SafeLand "Living with landslide risk in Europe: Assessment, effects of global change, and risk management strategies", a compendium of structural and non-structural mitigation measures for different landslide types in Europe was prepared, and the measures were assembled into a web-based "toolbox". Emphasis was placed on providing a rational and flexible framework applicable to existing and future mitigation measures. The purpose of web-based toolbox is to assist decision-making and to guide the user in the choice of the most appropriate mitigation measures. The mitigation measures were classified into three categories, describing whether the mitigation measures addressed the landslide hazard, the vulnerability or the elements at risk themselves. The measures considered include structural measures reducing hazard and non-structural mitigation measures, reducing either the hazard or the consequences (or vulnerability and exposure of elements at risk). The structural measures include surface protection and control of surface erosion; measures modifying the slope geometry and/or mass distribution; measures modifying surface water regime - surface drainage; measures mo¬difying groundwater regime - deep drainage; measured modifying the mechanical charac¬teristics of unstable mass; transfer of loads to more competent strata; retaining structures (to modify slope geometry and/or to transfer stress to compe¬tent layer); deviating the path of landslide debris; dissipating the energy of debris flows; and arresting and containing landslide debris or rock fall. The non-structural mitigation measures, reducing either the hazard or the consequences: early warning systems; restricting or discouraging construction activities; increasing resistance or coping capacity of elements at risk; relocation of elements at risk; sharing of risk through insurance. The measures are described in the toolbox with fact sheets providing a

  4. A more productive, but different, ocean after mitigation

    NASA Astrophysics Data System (ADS)

    John, Jasmin G.; Stock, Charles A.; Dunne, John P.

    2015-11-01

    Reversibility studies suggest a lagged recovery of global mean sea surface temperatures after mitigation, raising the question of whether a similar lag is likely for marine net primary production (NPP). Here we assess NPP reversibility with a mitigation scenario in which projected Representative Concentration Pathway (RCP) 8.5 forcings are applied out to 2100 and then reversed over the course of the following century in a fully coupled carbon-climate Earth System Model. In contrast to the temperature lag, we find a rapid increase in global mean NPP, including an overshoot to values above contemporary means. The enhanced NPP arises from a transient imbalance between the cooling surface ocean and continued warming in subsurface waters, which weakens upper ocean density gradients, resulting in deeper mixing and enhanced surface nitrate. We also find a marine ecosystem regime shift as persistent silicate depletion results in increased prevalence of large, non-diatom phytoplankton.

  5. Reassessing Biological Threats: Implications for Cooperative Mitigation Strategies

    PubMed Central

    Galloway, Summer Elise; Petzing, Stephanie Rachel; Young, Catharine Grace

    2015-01-01

    Multiple factors ranging from globalization to ecosystem disruption are presenting the global community with evolving biological threats to local, national, and global security that reach beyond the realm of traditional bioweapon threats. As a result, mitigation strategies have adapted necessarily to the increased diversity of biological threats. In general, response and preparedness strategies have largely shifted from being primarily reactive to traditional biological weapons to more proactive in nature. In this review, we briefly explore biological threats through a wider aperture, to embrace a greater appreciation of viral pathogens, antimicrobial resistance, and agricultural pathogens, and their potential to cause civil, economic, and political devastation. In addition, we discuss current mitigation strategies codified by the Global Health Security Agenda and the One Health paradigm as well as some of the available tools to assist with their sustainable implementation. PMID:26649289

  6. Mitigation strategies for microbiologically influenced corrosion in gas industry facilities

    SciTech Connect

    Pope, D.H.; Zintel, T.P. ); Cookingham, B.A. ); Howard, D.; Morris, R.G. ); Day, R.A.; Frank, J.R. ); Pogemiller, G.E. )

    1989-01-01

    This paper reports on a study of microbiologically influenced corrosion (MIC) and its mitigation in gas industry facilities. The results show that MIC commonly occurs on both external and internal surfaces of pipes, in down hole tubulars and in process equipment such as separators. Mitigation strategies were tested in side-stream devices at several sites. The results demonstrate that many biocides and corrosion inhibitors are relatively ineffective in controlling the surface microbial populations, at least under the conditions of the tests. Detailed studies with glutaraldehyde demonstrated that reestablishment of surface MIC communities after removal of this biocide was very rapid. Continuous treatment with glutaraldehyde led to the development of surface microbial communities resistant to the effects of the biocide.

  7. Conceptual Study on Air Ingress Mitigation for VHTRs

    SciTech Connect

    Chang H. Oh; Eung S. Kim

    2012-09-01

    An air-ingress accident followed by a pipe break is considered as a critical event for a very high temperature gas-cooled reactor (VHTR) safety. Following helium depressurization, it is anticipated that unless countermeasures are taken, air will enter the core through the break leading to oxidation of the in-core graphite structure. Thus, without mitigation features, this accident might lead to severe exothermic chemical reactions of graphite and oxygen depending on the accident scenario and the design. Under extreme circumstances, a loss of core structural integrity may occur and lead to a detrimental situation for the VHTR safety. This paper discusses various air-ingress mitigation concepts applicable for the VHTRs. The study begins with identifying important factors (or phenomena) associated with the air-ingress accident using a root-cause analysis. By preventing main causes of the important events identified in the root-cause diagram, the basic air-ingress mitigation ideas were conceptually developed. Among them, two concepts were finally evaluated as effective candidates. One concept is to inject helium into the lower plenum which is a direct in-vessel helium injection. The other concept is to enclose the reactor with a non-pressure boundary consisting of an opening at the bottom, which is an ex-vessel enclosure boundary. Computational fluid dynamics (CFD) methods were used to validate these concepts. As a result, it was shown that both concepts can effectively mitigate the air-ingress process. In the first concept, the injected helium replaces the air in the core and the lower plenum upper part by buoyancy force because of its low density. It prevented air from moving into the reactor core showing great potential for mitigating graphite oxidation in the core. In the second concept, the air-ingress rate is controlled by molecular diffusion through the opening at the enclosure bottom after depressurization. Some modified reactor cavity design is expected to

  8. Mitigation of structureborne noise nuisance

    NASA Astrophysics Data System (ADS)

    Ko, Wing P.

    2005-09-01

    This paper presents a noise complaint case which was solved by me a few years ago in Hong Kong. A newlywed couple in the residential unit complained to the Government that the noise emitted from the pump room directly beneath their unit was very annoying, especially in the night-time period. The owner of the building was then required by the Government to mitigate the noise to the night-time statutory noise requirement within 30 days, otherwise he would be prosecuted. Ideally, the structureborne noise from the pump room could be effectively mitigated by installation of floating slab and vibration isolators under the pumps. Also, the water tanks and water pipes were required to be isolated from the walls and floor. However, this work was impossible to be completed within 30 days to stop the prosecution. Water supply to the above residents would be seriously interrupted during the construction period. As the only noise parameter of the statutory requirement was 30 minute A-weighted Leq, the most effective and practical way in this exigent situation was to reduce the pump operation time within any 30 minute period to decrease the Leq values. In addition, the water pipes and pumps were also required to be isolated from the walls and floor with resilient materials to break the vibration channels. These noise mitigation measures were successfully applied to the pump room before the end of the 30 days. Finally, the noise levels inside the complainant's unit were found to meet the statutory requirement. The noise complaint case was then closed by the Government.

  9. Smart disaster mitigation in Thailand

    NASA Astrophysics Data System (ADS)

    Aimmanee, S.; Ekkawatpanit, C.; Asanuma, H.

    2016-04-01

    Thailand is notoriously exposed to several natural disasters, from heavy thunder storms to earthquakes and tsunamis, since it is located in the tropical area and has tectonic cracks underneath the ground. Besides these hazards flooding, despite being less severe, occurs frequently, stays longer than the other disasters, and affects a large part of the national territory. Recently in 2011 have also been recorded the devastating effects of major flooding causing the economic damages and losses around 50 billion dollars. Since Thailand is particularly exposed to such hazards, research institutions are involved in campaigns about monitoring, prevention and mitigation of the effects of such phenomena, with the aim to secure and protect human lives, and secondly, the remarkable cultural heritage. The present paper will first make a brief excursus on the main Thailand projects aimed at the mitigation of natural disasters, referring to projects of national and international relevance, being implemented, such as the ESCAP1999 (flow regime regulation and water conservation). Adaptable devices such as foldable flood barriers and hydrodynamically supported temporary banks have been utilized when flooding. In the second part of the paper, will be described some new ideas concerning the use of smart and biomimicking column structures capable of high-velocity water interception and velocity detection in the case of tsunami. The pole configuration is composite cylindrical shell structure embedded with piezoceramic sensor. The vortex shedding of the flow around the pole induces the vibration and periodically strains the piezoelectric element, which in turn generates the electrical sensorial signal. The internal space of the shell is filled with elastic foam to enhance the load carrying capability due to hydrodynamic application. This more rigid outer shell inserted with soft core material resemble lotus stem in nature in order to prolong local buckling and ovalization of column

  10. Passive mitigation of mode instabilities

    NASA Astrophysics Data System (ADS)

    Jauregui, C.; Otto, H.-J.; Stutzki, F.; Jansen, F.; Limpert, J.; Tünnermann, A.

    2014-03-01

    The phenomenon of mode instabilities has quickly become the most limiting effect for a further scaling of the average power of fiber laser systems. Consequently it is of great importance to find solutions for this problem. In this work we propose two concrete possible passive mitigation strategies: the first one is based on the reduction of the heat load in the fiber, whereas the second one is based on the reduction of the pump absorption. In both cases a significant increase of the threshold is expected.