Dynamics of an Overdriven Nitromethane Initiation System

NASA Astrophysics Data System (ADS)

Hároz, E. H.; Rae, P. J.; Armstrong, C. L.; Baca, E. V.; Campbell, C.; Gunderson, J. A.; Holmes, M.; Lopez-Pulliam, I.; Vaughan, L. D.; Dickson, P. M.

2017-06-01

For upcoming large-scale HE experiments, an initiation system is needed to ensure uniform and simultaneous burn. To that end, we developed an initiation system based on nitromethane. Initial, small-scale tests characterized the response of the nitromethane in the proposed cylindrical initiator geometry, indicating robust detonation under a variety of conditions such as a plane wave lenses & cylinders of PBX 9501 into a flyer plate or direct-drive. Detonation velocity, as measured by piezoelectric pin time-of-arrival measurements along the length and at bottom of vessel, shows an overdriven response. All cases show a detonation velocity faster than the literature value of 7.3 km s-1 for nitromethane, with the fastest velocity occurring for the 8-detonator, 8'' cylinder case with a velocity = 7.7 km s-1. Streak camera imaging characterized the curvature of the shock front as it arrived at the bottom of the vessel via spark gap. A final test of the initiator system looked at the expansion of the initiator vessel walls via PDV, showing velocities up to 3.5 km s-1. Finally, our initiator was placed inside a secondary vessel containing 1000 lbs of nitromethane. High-speed photography & pin data indicate complete symmetrical burn of the secondary nitromethane.

TIME-SEQUENCED X-RAY OBSERVATION OF A THERMAL EXPLOSION

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

Tringe, J. W.; Molitoris, J. D.; Kercher, J. R.

The evolution of a thermally-initiated explosion is studied using a multiple-image x-ray system. HMX-based PBX 9501 is used in this work, enabling direct comparison to recently-published data obtained with proton radiography [1]. Multiple x-ray images of the explosion are obtained with image spacing of ten microseconds or more. The explosion is simultaneously characterized with a high-speed camera using an interframe spacing of 11 mus. X-ray and camera images were both initiated passively by signals from an embedded thermocouple array, as opposed to being actively triggered by a laser pulse or other external source. X-ray images show an accelerating reacting frontmore » within the explosive, and also show unreacted explosive at the time the containment vessel bursts. High-speed camera images show debris ejected from the vessel expanding at 800-2100 m/s in the first tens of mus after the container wall failure. The effective center of the initiation volume is about 6 mm from the geometric center of the explosive.« less

High stress shallow moonquakes - Evidence for an initially totally molten moon

NASA Technical Reports Server (NTRS)

Binder, A. B.; Oberst, J.

1985-01-01

Thermoelastic stress calculations show that if the moon was initially molten only in the outer few hundred kilometers, as in the magma ocean model of the moon, the highlands crust should be aseismic. In contrast, if the moon was initially totally molten, high stress (1 to more than about 3 kbar), shallow (0 to about 6 km deep), compressional moonquakes should be occurring in the highlands crust. Calculations of the minimum stress drops made for the 28 observed shallow moonquakes suggest that 3 of them probably have stress drops in the kbar range. Thus, these very limited seismic data are consistent with the model that the moon was initially totally molten.

Are persistent early onset child conduct problems predicted by the trajectories and initial levels of discipline practices?

PubMed

Lorber, Michael F; Slep, Amy M Smith

2015-08-01

In the present investigation we focused on 2 broad sets of questions: Do parental overreactivity, laxness, and corporal punishment show evidence of normative change in early to middle childhood? Are persistently elevated child conduct problems (CPs) associated with deviations from normative changes in, as well as high initial levels of, discipline practices? Four hundred fifty-three couples with 3- to 7-year-old children were recruited via random digit dialing and studied at 3 annual assessments. Parents completed questionnaire measures of all study constructs. Normative declines were found in maternal corporal punishment and laxness. Maternal overreactivity showed a normative increase. For fathers, only corporal punishment showed evidence of a normative decline. The declines in mothers' corporal punishment and laxness, and in fathers' corporal punishment, exhibited little variability. In contrast, the trajectories of maternal overreactivity were significantly variable. High-increasing CPs were more common than low-stable CPs in families with greater increases in maternal overreactivity. High-increasing CPs were also more common in families with greater initial maternal overreactivity and corporal punishment. Yet in no case did discipline practices significantly distinguish children on high-increasing versus high-decreasing CPs trajectories. In tests of alternative models, child effects were found for all parenting variables, suggesting reciprocal causation. The findings are discussed relative to etiological models of CPs and implications for preventive intervention. (c) 2015 APA, all rights reserved).

Are the uterine serous carcinomas underdiagnosed? Histomorphologic and immunohistochemical correlates and clinical follow up in high-grade endometrial carcinomas initially diagnosed as high-grade endometrioid carcinoma.

PubMed

Hu, Shaomin; Hinson, Jeff L; Matnani, Rahul; Cibull, Michael L; Karabakhtsian, Rouzan G

2018-02-01

Histologic subclassification of high-grade endometrial carcinomas can sometimes be a diagnostic challenge when based on histomorphology alone. Here we utilized immunohistochemical markers to determine the immunophenotype in histologically ambiguous high-grade endometrial carcinomas that were initially diagnosed as pure or mixed high-grade endometrioid carcinoma, aiming to determine the utility of selected immunohistochemical panel in accurate classification of these distinct tumor types, while correlating these findings with the clinical outcome. A total of 43 high-grade endometrial carcinoma cases initially classified as pure high-grade endometrioid carcinoma (n=32), mixed high-grade endometrioid carcinoma/serous carcinoma (n=9) and mixed high-grade endometrioid carcinoma/clear cell carcinoma (n=2) were retrospectively stained with a panel of immunostains, including antibodies for p53, p16, estrogen receptor, and mammaglobin. Clinical follow-up data were obtained, and stage-to-stage disease outcomes were compared for different tumor types. Based on aberrant staining for p53 and p16, 17/43 (40%) of the high-grade endometrial carcinoma cases initially diagnosed as high-grade endometrioid carcinoma were re-classified as serous carcinoma. All 17 cases showed negative staining for mammaglobin, while estrogen receptor was positive in only 6 (35%) cases. The remaining 26 cases of high-grade endometrioid carcinoma showed wild-type staining for p53 in 25 (96%) cases, patchy staining for p16 in 20 (77%) cases, and were positive for mammaglobin and estrogen receptor in 8 (31%) and 19 (73%) cases, respectively, thus the initial diagnosis of high-grade endometrioid carcinoma was confirmed in these cases. In addition, the patients with re-classified serous carcinoma had advanced clinical stages at diagnosis and poorer overall survival on clinical follow-up compared to that of the remaining 26 high-grade endometrioid carcinoma cases. These results indicate that selected immunohistochemical panel, including p53, p16, and mammaglobin can be helpful in reaching accurate diagnosis in cases of histomorphologically ambiguous endometrial carcinomas, and can assist in providing guidance for appropriate therapeutic options for the patients.

Durability of Pt-Co Alloy Polymer Electrolyte Fuel Cell Cathode Catalysts under Accelerated Stress Tests

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

Papadias, D. D.; Ahluwalia, R. K.; Kariuki, N.

The durability of Pt-Co alloy cathode catalysts supported on high surface area carbon is investigated by subjecting them to accelerated stress tests (ASTs). The catalysts had different initial Co contents and nanoparticle morphologies: a “spongy” porous morphology for the high-Co (H) content catalyst, and a fully alloyed crystalline morphology for the medium-Co (M) and low-Co (L) content catalysts. The specific activity of the catalysts depends on their initial Co content, morphology and nanoparticle size, and remained higher than 1000 μA/cm 2-Pt after 27–50% Co loss. The H-catalyst electrode showed the smallest kinetic overpotentials (η c s) due to higher initialmore » Pt loading than the other two electrodes, but it had the fastest increase in ηcs with AST cycling due to lower Co retention; the L-catalyst electrode showed higher η c s due to a lower initial Pt loading, but had a smaller increase in η c s with aging due to higher Co retention; the M-catalyst electrode showed a similar increase in η c s with aging, but this increase was due to the combined effects of Co dissolution and electrochemically active surface area (ECSA) loss. In conclusion, the modeled increase in mass transfer overpotentials with aging correlates with the initial Pt loading, ECSA loss and the initial catalyst morphology« less

Durability of Pt-Co Alloy Polymer Electrolyte Fuel Cell Cathode Catalysts under Accelerated Stress Tests

DOE PAGES

Papadias, D. D.; Ahluwalia, R. K.; Kariuki, N.; ...

2018-03-17

The durability of Pt-Co alloy cathode catalysts supported on high surface area carbon is investigated by subjecting them to accelerated stress tests (ASTs). The catalysts had different initial Co contents and nanoparticle morphologies: a “spongy” porous morphology for the high-Co (H) content catalyst, and a fully alloyed crystalline morphology for the medium-Co (M) and low-Co (L) content catalysts. The specific activity of the catalysts depends on their initial Co content, morphology and nanoparticle size, and remained higher than 1000 μA/cm 2-Pt after 27–50% Co loss. The H-catalyst electrode showed the smallest kinetic overpotentials (η c s) due to higher initialmore » Pt loading than the other two electrodes, but it had the fastest increase in ηcs with AST cycling due to lower Co retention; the L-catalyst electrode showed higher η c s due to a lower initial Pt loading, but had a smaller increase in η c s with aging due to higher Co retention; the M-catalyst electrode showed a similar increase in η c s with aging, but this increase was due to the combined effects of Co dissolution and electrochemically active surface area (ECSA) loss. In conclusion, the modeled increase in mass transfer overpotentials with aging correlates with the initial Pt loading, ECSA loss and the initial catalyst morphology« less

Possible sources of forecast errors generated by the global/regional assimilation and prediction system for landfalling tropical cyclones. Part I: Initial uncertainties

NASA Astrophysics Data System (ADS)

Zhou, Feifan; Yamaguchi, Munehiko; Qin, Xiaohao

2016-07-01

This paper investigates the possible sources of errors associated with tropical cyclone (TC) tracks forecasted using the Global/Regional Assimilation and Prediction System (GRAPES). The GRAPES forecasts were made for 16 landfalling TCs in the western North Pacific basin during the 2008 and 2009 seasons, with a forecast length of 72 hours, and using the default initial conditions ("initials", hereafter), which are from the NCEP-FNL dataset, as well as ECMWF initials. The forecasts are compared with ECMWF forecasts. The results show that in most TCs, the GRAPES forecasts are improved when using the ECMWF initials compared with the default initials. Compared with the ECMWF initials, the default initials produce lower intensity TCs and a lower intensity subtropical high, but a higher intensity South Asia high and monsoon trough, as well as a higher temperature but lower specific humidity at the TC center. Replacement of the geopotential height and wind fields with the ECMWF initials in and around the TC center at the initial time was found to be the most efficient way to improve the forecasts. In addition, TCs that showed the greatest improvement in forecast accuracy usually had the largest initial uncertainties in TC intensity and were usually in the intensifying phase. The results demonstrate the importance of the initial intensity for TC track forecasts made using GRAPES, and indicate the model is better in describing the intensifying phase than the decaying phase of TCs. Finally, the limit of the improvement indicates that the model error associated with GRAPES forecasts may be the main cause of poor forecasts of landfalling TCs. Thus, further examinations of the model errors are required.

Friction and Environmental Sensitivity of Molybdenum Disulfide: Effects of Microstructure

NASA Astrophysics Data System (ADS)

Curry, John F.

For nearly a century, molybdenum disulfide has been employed as a solid lubricant to reduce the friction and wear between surfaces. MoS2 is in a class of unique materials, transition metal dichalcogens (TMDC), that have a single crystal structure forming lamellae that interact via weak van der Waals forces. This dissertation focuses on the link between the microstructure of MoS2 and the energetics of running film formation to reduce friction, and effects of environmental sensitivities on performance. Nitrogen impinged MoS2 films are utilized as a comparator to amorphous PVD deposited MoS2 in many of the studies due to the highly ordered surface parallel basal texture of sprayed films. Comparisons showed that films with a highly ordered structure can reduce high friction behavior during run-in. It is thought that shear induced reorientation of amorphous films contributes to typically high initial friction during run-in. In addition to a reduction in initial friction, highly ordered MoS2 films are shown to be more resistant to penetration from oxidative aging processes. High sensitivity, low-energy ion scattering (HS-LEIS) enabled depth profiles that showed oxidation limited to the first monolayer for ordered films and throughout the depth (4-5 nm) for amorphous films. X-ray photoelectron spectroscopy supported these findings, showing far more oxidation in amorphous films than ordered films. Many of these results show the benefits of a well run-in coating, yet transient increases in initial friction can still be noticed after only 5 - 10 minutes. It was found that the transient return to high initial friction after dwell times past 5 - 10 minutes was not due to adsorbed species such as water, but possibly an effect of basal plane relaxation to a commensurate state. Additional techniques and methods were developed to study the effect of adsorbed water and load on running film formation via spiral orbit XRD studies. Spiral orbit experiments enabled large enough worn areas for study in the XRD. Diffraction patterns for sputtered coatings at high loads (1N) showed more intense signals for surface parallel basal plane representation than lower loads (100mN). Tests run in dry and humid nitrogen (20% RH), however, showed no differences in reorientation of basal planes. Microstructure was found to be an important factor in determining the tribological performance of MoS2 films in a variety of testing conditions and environments. These findings will be useful in developing a mechanistic framework that better understands the energetics of running film formation and how different environments play a role.

Back off! The effect of emotion on backward step initiation.

PubMed

Bouman, Daniëlle; Stins, John F

2018-02-01

The distance regulation (DR) hypothesis states that actors are inclined to increase their distance from an unpleasant stimulus. The current study investigated the relation between emotion and its effect on the control of backward step initiation, which constitutes an avoidance-like behavior. Participants stepped backward on a force plate in response to neutral, high-arousing pleasant and high-arousing unpleasant visual emotional stimuli. Gait initiation parameters and the results of an exploratory analysis of postural sway were compared across the emotion categories using significance testing and Bayesian statistics. Evidence was found that gait initiation parameters were largely unaffected by emotional conditions. In contrast, the exploratory analysis of postural immobility showed a significant effect: highly arousing stimuli (pleasant and unpleasant) resulted in more postural sway immediately preceding gait initiation compared to neutral stimuli. This suggests that arousal, rather than valence, affects pre-step sway. These results contradict the DR hypothesis, since avoidance gait-initiation in response to unpleasant stimuli was no different compared to pleasant stimuli. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

Study on the Structures of Two Booster Pellets Having High Initiation Capacity

NASA Astrophysics Data System (ADS)

Shuang-Qi, Hu; Hong-Rong, Liu; Li-shuang, Hu; Xiong, Cao; Xiang-Chao, Mi; Hai-Xia, Zhao

2014-05-01

Insensitive munitions (IM) improve the survivability of both weapons and their associated platforms, which can lead to a reduction in casualties, mission losses, and whole life costs. All weapon systems contain an explosive train that needs to meet IM criteria but reliably initiate a main charge explosive. To ensure that these diametrically opposed requirements can be achieved, new highly effective booster charge structures were designed. The initiation capacity of the two booster pellets was studied using varied composition and axial-steel-dent methods. The results showed that the two new booster pellets can initiate standard main charge pellets with less explosive mass than the ordinary cylindrical booster pellet. The numerical simulation results were in good agreement with the experiment results.

Silicon Carbide Radioisotope Batteries

NASA Technical Reports Server (NTRS)

Rybicki, George C.

2005-01-01

The substantial radiation resistance and large bandgap of SiC semiconductor materials makes them an attractive candidate for application in a high efficiency, long life radioisotope battery. To evaluate their potential in this application, simulated batteries were constructed using SiC diodes and the alpha particle emitter Americium Am-241 or the beta particle emitter Promethium Pm-147. The Am-241 based battery showed high initial power output and an initial conversion efficiency of approximately 16%, but the power output decayed 52% in 500 hours due to radiation damage. In contrast the Pm-147 based battery showed a similar power output level and an initial conversion efficiency of approximately 0.6%, but no degradation was observed in 500 hours. However, the Pm-147 battery required approximately 1000 times the particle fluence as the Am-242 battery to achieve a similar power output. The advantages and disadvantages of each type of battery and suggestions for future improvements will be discussed.

Initiated chemical vapor deposition polymers for high peak-power laser targets

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

Baxamusa, Salmaan H.; Lepro, Xavier; Lee, Tom

2016-12-05

Here, we report two examples of initiated chemical vapor deposition (iCVD) polymers being developed for use in laser targets for high peak-power laser systems. First, we show that iCVD poly(divinylbenzene) is more photo-oxidatively stable than the plasma polymers currently used in laser targets. Thick layers (10–12 μm) of this highly crosslinked polymer can be deposited with near-zero intrinsic film stress. Second, we show that iCVD epoxy polymers can be crosslinked after deposition to form thin adhesive layers for assembling precision laser targets. The bondlines can be made as thin as ~ 1 μm, approximately a factor of 2 thinner thanmore » achievable using viscous resin-based adhesives. These bonds can withstand downstream coining and stamping processes.« less

Autonomic functioning in mothers with interpersonal violence-related posttraumatic stress disorder in response to separation-reunion.

PubMed

Schechter, Daniel S; Moser, Dominik A; McCaw, Jaime E; Myers, Michael M

2014-05-01

This study characterizes autonomic nervous system activity reactive to separation-reunion among mothers with Interpersonal Violence-Related Posttraumatic Stress Disorder (IPV-PTSD). Heart-rate (HR) and high frequency heart-rate-variability (HF-HRV) were measured in 17 IPV-PTSD-mothers, 22 sub-threshold-mothers, and 15 non-PTSD mother-controls while interacting with their toddlers (12-48 months). Analyses showed IPV-PTSD-mothers having generally lower HR than other groups. All groups showed negative correlations between changes in HR and HF-HRV from sitting- to standing-baseline. During initial separation, controls no longer showed a negative relationship between HR and HF-HRV. But by the second reunion, the negative relationship reappeared. IPV-PTSD- and sub-threshold-mothers retained negative HR/HF-HRV correlations during the initial separation, but stopped showing them by the second reunion. Results support that mother-controls showed a pattern of autonomic regulation suggestive of hypervigilance during initial separation that resolved by the time of re-exposure. PTSD-mothers showed delayed onset of this pattern only upon re-exposure, and were perhaps exhibiting defensive avoidance or numbing during the initial separation/reunion. © 2013 Wiley Periodicals, Inc.

Eye-movement evidence of the time-course of attentional bias for threatening pictures in test-anxious students.

PubMed

Dong, Yunying; De Beuckelaer, Alain; Yu, Liang; Zhou, Renlai

2017-06-01

Protocols for measuring attentional bias to threat in test-anxiety, a special form of trait-anxiety, are rarely found in the literature. In our eye-tracking study, we introduced a new protocol, and studied the time-course of attention to test-related pictures with varying threat levels in 22 high test-anxious (HTA) and 22 low test-anxious (LTA) subjects. To determine whether attentional bias to test-related pictures is due to test-anxiety and not to state-anxiety, we also included a third group of 22 subjects with high state-anxiety but low test-anxiety (HSA). The subjects completed a free viewing task (FVT) in which high threat-neutral (HT-N) and low threat-neutral (LT-N) picture pairs were presented for 3 s. The results demonstrated that: (1) HTA subjects showed initial orienting to LT pictures, early attentional engagement with HT pictures later on and avoidance of HT pictures at the very end; (2) LTA subjects showed initial orienting to HT pictures and maintenance of attention on them later on; while (3) HSA subjects showed an initial orientation towards LT pictures and maintenance of attention on LT and HT pictures later on. These results suggest that, (high) test-anxiety is also prone to attentional bias towards test-related threat stimuli. Implications for future research are discussed.

The "I" in us, or the eye on us? Regulatory focus, commitment and derogation of an attractive alternative person.

PubMed

Rodrigues, David; Lopes, Diniz; Kumashiro, Madoka

2017-01-01

When individuals are highly committed to their romantic relationship, they are more likely to engage in pro-relationship maintenance mechanisms. The present research expanded on the notion that commitment redirects self-oriented goals to consider broader relational goals and examined whether commitment interacts with a promotion and prevention focus to activate derogation of attractive alternatives. Three studies used cross-sectional and experimental approaches. Study 1 showed that romantically involved individuals predominantly focused on promotion, but not prevention, reported less initial attraction to an attractive target than single individuals, especially when highly committed to their relationship. Study 2 showed that romantically involved individuals induced in a promotion focus, compared to those in prevention focus, reported less initial attraction, but only when more committed to their relationship. Regardless of regulatory focus manipulation, more committed individuals were also less likely to perceive quality among alternative scenarios and to be attentive to alternative others in general. Finally, Study 3 showed that romantically involved individuals induced in promotion focus and primed with high commitment reported less initial attraction, than those primed with low commitment, or than those induced in prevention focus. Once again, for these latter no differences occurred according to commitment prime. Together, the findings suggest that highly committed promotion focused individuals consider broader relationship goals and activate relationship maintenance behaviors such as derogation of attractive alternatives to promote their relationship.

Cauchy problem with general discontinuous initial data along a smooth curve for 2-d Euler system

NASA Astrophysics Data System (ADS)

Chen, Shuxing; Li, Dening

2014-09-01

We study the Cauchy problems for the isentropic 2-d Euler system with discontinuous initial data along a smooth curve. All three singularities are present in the solution: shock wave, rarefaction wave and contact discontinuity. We show that the usual restrictive high order compatibility conditions for the initial data are automatically satisfied. The local existence of piecewise smooth solution containing all three waves is established.

Retaining {1 0 0} texture from initial columnar grains in 6.5 wt% Si electrical steels

NASA Astrophysics Data System (ADS)

Liang, Ruiyang; Yang, Ping; Mao, Weimin

2017-11-01

6.5 wt% Si electrical steel is a superior soft magnetic material with excellent magnetic properties which highly depends on texture. In this study, based on the heredity of 〈0 0 1〉 orientation in columnar grains, columnar grains are used as the initial material to prepare non-oriented 6.5 wt% Si electrical steel with excellent magnetic properties. EBSD and XRD techniques are adopted to explore the structure and texture evolution during hot rolling, warm rolling, cold rolling and annealing. The results show that, due to the heredity of "structure and texture" from the initial strong {1 0 0} columnar grains, annealed sheet with {1 0 0}〈0 0 1〉 texture had better magnetic properties, which can be used as non-oriented high-silicon electrical steel. Both preferred cube grain nucleation in deformed {1 1 3}〈3 6 1〉 grains in subsurface and coarse {1 0 0}〈0 0 1〉 deformed grains in center layer show the effect of initial columnar grains with {1 0 0} texture.

Preliminary Results of Solid Gas Generator Micropropulsion

NASA Technical Reports Server (NTRS)

deGroot, Wilhelmus A.; Reed, Brian D.; Brenizer, Marshall

1999-01-01

A decomposing solid thruster concept, which creates a more benign thermal and chemical environment than solid propellant combustion, while maintaining, performance similar to solid combustion, is described. A Micro-Electro-Mechanical (MEMS) thruster concept with diode laser and fiber-optic initiation is proposed, and thruster components fabricated with MEMS technology are presented. A high nitrogen content solid gas generator compound is evaluated and tested in a conventional axisymmetric thrust chamber with nozzle throat area ratio of 100. Results show incomplete decomposition of this compound in both low pressure (1 kPa) and high pressure (1 MPa) environments, with decomposition of up to 80% of the original mass. Chamber pressures of 1.1 MPa were obtained, with maximum calculated thrust of approximately 2.7 N. Resistively heated wires and resistively heated walls were used to initiate decomposition. Initiation tests using available lasers were unsuccessful, but infrared spectra of the compound show that the laser initiation tests used inappropriate wavelengths for optimal propellant absorption. Optimal wavelengths for laser ignition were identified. Data presented are from tests currently in progress. Alternative solid gas generator compounds are being evaluated for future tests.

A platform for studying the Rayleigh-Taylor and Richtmyer-Meshkov instabilities in a planar geometry at high energy density at the National Ignition Facility

NASA Astrophysics Data System (ADS)

Nagel, S. R.; Raman, K. S.; Huntington, C. M.; MacLaren, S. A.; Wang, P.; Barrios, M. A.; Baumann, T.; Bender, J. D.; Benedetti, L. R.; Doane, D. M.; Felker, S.; Fitzsimmons, P.; Flippo, K. A.; Holder, J. P.; Kaczala, D. N.; Perry, T. S.; Seugling, R. M.; Savage, L.; Zhou, Y.

2017-07-01

A new experimental platform has been developed at the National Ignition Facility (NIF) for studying the Rayleigh-Taylor (RT) and Richtmyer-Meshkov (RM) instabilities in a planar geometry at high-energy-densities. The platform uses 60 beams of the NIF laser to drive an initially solid shock tube containing a pre-machined interface between dense and light materials. The strong shock turns the initially solid target into a plasma and the material boundary into a fluid interface with the imprinted initial condition. The interface evolves by action of the RT and RM instabilities, and the growth is imaged with backlit x-ray radiography. We present our first data involving sinusoidal interface perturbations driven from the heavy side to the light side. Late-time radiographic images show the initial conditions reaching the deeply nonlinear regime, and an evolution of fine structure consistent with a transition to turbulence. We show preliminary comparisons with post-shot numerical simulations and discuss the implications for future campaigns.

Time-sequenced X-ray Observation of a Thermal Explosion

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

Tringe, J W; Molitoris, J D; Smilowitz, L

The evolution of a thermally-initiated explosion is studied using a multiple-image x-ray system. HMX-based PBX 9501 is used in this work, enabling direct comparison to recently-published data obtained with proton radiography [1]. Multiple x-ray images of the explosion are obtained with image spacing of ten microseconds or more. The explosion is simultaneously characterized with a high-speed camera using an interframe spacing of 11 {micro}s. X-ray and camera images were both initiated passively by signals from an embedded thermocouple array, as opposed to being actively triggered by a laser pulse or other external source. X-ray images show an accelerating reacting frontmore » within the explosive, and also show unreacted explosive at the time the containment vessel bursts. High-speed camera images show debris ejected from the vessel expanding at 800-2100 m/s in the first tens of {micro}s after the container wall failure. The effective center of the initiation volume is about 6 mm from the geometric center of the explosive.« less

Shock initiation of explosives: High temperature hot spots explained

NASA Astrophysics Data System (ADS)

Bassett, Will P.; Johnson, Belinda P.; Neelakantan, Nitin K.; Suslick, Kenneth S.; Dlott, Dana D.

2017-08-01

We investigated the shock initiation of energetic materials with a tabletop apparatus that uses km s-1 laser-driven flyer plates to initiate tiny explosive charges and obtains complete temperature histories with a high dynamic range. By comparing various microstructured formulations, including a pentaerythritol tetranitrate (PETN) based plastic explosive (PBX) denoted XTX-8003, we determined that micron-scale pores were needed to create high hot spot temperatures. In charges where micropores (i.e., micron-sized pores) were present, a hot spot temperature of 6000 K was observed; when the micropores were pre-compressed to nm scale, however, the hot spot temperature dropped to ˜4000 K. By comparing XTX-8003 with an analog that replaced PETN by nonvolatile silica, we showed that the high temperatures require gas in the pores, that the high temperatures were created by adiabatic gas compression, and that the temperatures observed can be controlled by the choice of ambient gases. The hot spots persist in shock-compressed PBXs even in vacuum because the initially empty pores became filled with gas created in-situ by shock-induced chemical decomposition.

Novel Pathways of Nitroaromatic Metabolism: Hydroxylamine Formation, Reactivity and Potential for Ring Fission for Destruction of TNT-CU1214

DTIC Science & Technology

2005-08-15

phase was terminated when HPLC analysis showed that the initial TNT was in the form of DHA6NT and aminophenols , products that have been reported...terminated when HPLC analysis showed that the initial TNT was in the form of DHA6NT and aminophenols , products that have been reported previously (2...Department of Defense HPLC High Performance Liquid Chromatography IPTG Isopropyl-β-D-1-thiogalactopyranoside LB Luria-Bertani Broth NB Nitrobenzene

[Successful treatment of HIV-associated chronic inflammatory demyelinating polyneuropathy by early initiation of highly active anti-retroviral therapy].

PubMed

Kume, Kodai; Ikeda, Kazuyo; Kamada, Masaki; Touge, Tetsuo; Deguchi, Kazushi; Masaki, Tsutomu

2013-01-01

A 47-year-old man with HIV infection presented with lower leg dominant dysesthesia, muscle weakness and sensory ataxia of 3 month's duration. Nerve conduction studies (NCS) showed demyelination change in the median and tibial nerves and sensory nerve action potential (SNAP) in the sural nerve was not evoked. Somatosensory evoked potential (SEP) showed the delayed N9 latency. Diagnose of HIV-associated chronic inflammatory demyelinating polyneuropathy (CIDP) was made. Although the CD4 lymphocyte counts were relatively preserved (466/μl), highly active anti-retroviral therapy (HAART) was started according to a new guideline for the use of antiretroviral agents in HIV-1-infected adults and adolescents recommending early initiation of treatment. After six months, HIV1-RNA was not detected and the CD4 lymphocyte counts showed a recovering trend (585/μl). His symptoms had disappeared, except for dysesthesia in the tip of a toe. Repeated NCS demonstrated full recovery from the demyelination and appearance of SNAP in the sural nerve. The improvement of his symptoms and NCS findings has been maintained for two years. Although effectiveness of immunotherapies such as oral prednisone, high-dose immunoglobulins and plasmapheresis have been reported in HIV-associated CIDP, early initiation of HAART may be also important for favorable prognosis in HIV-associated CIDP.

Conformational plasticity of RepB, the replication initiator protein of promiscuous streptococcal plasmid pMV158

PubMed Central

Boer, D. Roeland; Ruiz-Masó, José Angel; Rueda, Manuel; Petoukhov, Maxim V.; Machón, Cristina; Svergun, Dmitri I.; Orozco, Modesto; del Solar, Gloria; Coll, Miquel

2016-01-01

DNA replication initiation is a vital and tightly regulated step in all replicons and requires an initiator factor that specifically recognizes the DNA replication origin and starts replication. RepB from the promiscuous streptococcal plasmid pMV158 is a hexameric ring protein evolutionary related to viral initiators. Here we explore the conformational plasticity of the RepB hexamer by i) SAXS, ii) sedimentation experiments, iii) molecular simulations and iv) X-ray crystallography. Combining these techniques, we derive an estimate of the conformational ensemble in solution showing that the C-terminal oligomerisation domains of the protein form a rigid cylindrical scaffold to which the N-terminal DNA-binding/catalytic domains are attached as highly flexible appendages, featuring multiple orientations. In addition, we show that the hinge region connecting both domains plays a pivotal role in the observed plasticity. Sequence comparisons and a literature survey show that this hinge region could exists in other initiators, suggesting that it is a common, crucial structural element for DNA binding and manipulation. PMID:26875695

The Detection And Analysis Of Blasting Problems Encountered In A Colliery Using High Speed Photography

NASA Astrophysics Data System (ADS)

Rorke, A. J.; Kohler, E. W.

1987-09-01

Premature initiation of ANFO (an explosive mixture of Ammonium Nitrate and Fuel Oil) at a large colliery, near Witbank, was first detected from routine high speed films taken of large mid-burden, and overburden blasts. The analysis of these films shows that the rapid migration of very hot gasses through cracks ahead of the blast may have caused the explosive to initiate prematurely. The problem was not seen in the less competent overburden rocks. A less sensitive explosive has been successfully tried. The assessment of these blasts using high speed photography is discussed.

Heart failure diagnosis in acute conditions has high agreement with inpatient diagnosis.

PubMed

Seronde, Marie-France; Laribi, Said; Collins, Sean P; Deye, Nicolas; Logeart, Damien; Plaisance, Patrick; Cohen-Solal, Alain; Mebazaa, Alexandre

2016-06-01

Acute heart failure (AHF) is frequently encountered in the emergency department (ED) or in the cardiac care unit (CCU)/ICU. Discrimination between cardiac and noncardiac cause of dyspnea by clinical means and standard testing is sometimes inadequate. The aim of our study was to assess AHF diagnosis agreement as determined by: (a) the attending physician, (b) the hospital discharge diagnosis, and (c) an adjudication committee. Between 2010 and 2011, consecutive patients arriving for dyspnea in our hospital were prospectively included. A convenience sample of patients was enrolled in this analysis. Patients were admitted through the ED (280 patients) or through CCU/ICU (112 patients) for undifferentiated dyspnea. Overall, few differences were observed between the initial diagnosis and the hospital discharge diagnosis or the adjudicated diagnosis. Among the 200 patients with an initial diagnosis of AHF, hospital discharge diagnosis confirmed AHF (alone or combined) in 191 (95.5%) patients and the adjudication committee confirmed AHF (alone or combined) in 196 (98%) patients. Our study showed considerable agreement between different AHF diagnostic standards. An initial AHF diagnosis on the basis of clinical signs and biological parameters utilizing B-type natriuretic peptide testing has high agreement and accuracy with the hospital discharge and adjudicated diagnosis of AHF. The present study also shows that the accuracy of the initial AHF diagnosis allows rapid inclusion in AHF trials. These results, if confirmed in a broader cohort of patients, suggest that the initial ED diagnosis is highly accurate and reliable to guide further inpatient management.

Modifying mixing and instability growth through the adjustment of initial conditions in a high-energy-density counter-propagating shear experiment on OMEGA

DOE PAGES

Merritt, E. C.; Doss, F. W.; Loomis, E. N.; ...

2015-06-24

Counter-propagating shear experiments conducted at the OMEGA Laser Facility have been evaluating the effect of target initial conditions, specifically the characteristics of a tracer foil located at the shear boundary, on Kelvin-Helmholtz instability evolution and experiment transition toward nonlinearity and turbulence in the high-energy-density (HED) regime. Experiments are focused on both identifying and uncoupling the dependence of the model initial turbulent length scale in variable-density turbulence models of k-ϵ type on competing physical instability seed lengths as well as developing a path toward fully developed turbulent HED experiments. We present results from a series of experiments controllably and independently varyingmore » two initial types of scale lengths in the experiment: the thickness and surface roughness (surface perturbation scale spectrum) of a tracer layer at the shear interface. We show that decreasing the layer thickness and increasing the surface roughness both have the ability to increase the relative mixing in the system, and thus theoretically decrease the time required to begin transitioning to turbulence in the system. In addition, we also show that we can connect a change in observed mix width growth due to increased foil surface roughness to an analytically predicted change in model initial turbulent scale lengths.« less

CRADA No. BNL-C-97-10 between BNL and Cotton, Inc. Final abstract and final report [Final Report of Research carried out under DOE CRADA No. BNL-C-97-10 - "Prediction of Yield in Cotton"

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

None, None

The objectives of this work were to determine if the numbér of fiber cell initials varied genetically and to compare the number of initials with that of mature fibers obtained at harvest time. The method used to count the number of fiber cell initials is direct, simple, quick and done while the plant is growing. In contrast, the currently used commercial process is indirect and needs large amount mature fibers gathered at harvest time. However, all current work on cotton yield is based on fiber numbers obtained by the indirect commercial process. Consequently, it was necessary to compare results obtainedmore » from the two methods using the same plants as the source of material. The results show that the number of fiber initials per ovule differed significantly (P>0.05) for seven cultivars in 1995 and 1996. AIso, a 1997 study shows the number of fiber initials varied by 15% over boll positions and environments, with rankings among cultivars generally consistent across boll positions and sampling times. Finally, although there were differences among cultivars for initial fiber cell number, all cultivars had nearly the same number of mature lint fibers per seed. This last finding is significant. It indicates that the rate of fiber cell initiation varies among cultivars; the lower the rate, the greater the difference between the number of initials and the number of mature fiber cells. If the rate of fiber initiation is relatively high, the number of initials and mature fibers differs by about 11%; if it is low, the difference is as high as 31%. Cotton breeders may be able to use genetic differences for the number of fiber initials and/or the rate of fiber cell initiation in crop improvement programs.« less

Hedgehog-GLI signaling drives self-renewal and tumorigenicity of human melanoma-initiating cells.

PubMed

Santini, Roberta; Vinci, Maria C; Pandolfi, Silvia; Penachioni, Junia Y; Montagnani, Valentina; Olivito, Biagio; Gattai, Riccardo; Pimpinelli, Nicola; Gerlini, Gianni; Borgognoni, Lorenzo; Stecca, Barbara

2012-09-01

The question of whether cancer stem/tumor-initiating cells (CSC/TIC) exist in human melanomas has arisen in the last few years. Here, we have used nonadherent spheres and the aldehyde dehydrogenase (ALDH) enzymatic activity to enrich for CSC/TIC in a collection of human melanomas obtained from a broad spectrum of sites and stages. We find that melanomaspheres display extensive in vitro self-renewal ability and sustain tumor growth in vivo, generating human melanoma xenografts that recapitulate the phenotypic composition of the parental tumor. Melanomaspheres express high levels of Hedgehog (HH) pathway components and of embryonic pluripotent stem cell factors SOX2, NANOG, OCT4, and KLF4. We show that human melanomas contain a subset of cells expressing high ALDH activity (ALDH(high)), which is endowed with higher self-renewal and tumorigenic abilities than the ALDH(low) population. A good correlation between the number of ALDH(high) cells and sphere formation efficiency was observed. Notably, both pharmacological inhibition of HH signaling by the SMOOTHENED (SMO) antagonist cyclopamine and GLI antagonist GANT61 and stable expression of shRNA targeting either SMO or GLI1 result in a significant decrease in melanoma stem cell self-renewal in vitro and a reduction in the number of ALDH(high) melanoma stem cells. Finally, we show that interference with the HH-GLI pathway through lentiviral-mediated silencing of SMO and GLI1 drastically diminishes tumor initiation of ALDH(high) melanoma stem cells. In conclusion, our data indicate an essential role of the HH-GLI1 signaling in controlling self-renewal and tumor initiation of melanoma CSC/TIC. Targeting HH-GLI1 is thus predicted to reduce the melanoma stem cell compartment. Copyright © 2012 AlphaMed Press.

Rambutan-like CNT-Al2O3 scaffolds for high-performance cathode catalyst layers of polymer electrolyte fuel cells

NASA Astrophysics Data System (ADS)

Chang, KwangHyun; Cho, Seonghun; Lim, Eun Ja; Park, Seok-Hee; Yim, Sung-Dae

2018-03-01

Rambutan-like CNT-Al2O3 scaffolds are introduced as a potential candidate for CNT-based catalyst supports to overcome the CNT issues, such as the easy bundling in catalyst ink and the poor pore structure of the CNT-based catalyst layers, and to achieve high MEA performance in PEFCs. Non-porous α-phase Al2O3 balls are introduced to enable the growth of multiwalled CNTs, and Pt nanoparticles are loaded onto the CNT surfaces. In a half-cell, the Pt/CNT-Al2O3 catalyst shows much higher durability than those of a commercial Pt/C catalyst even though it shows lower oxygen reduction reaction (ORR) activity than Pt/C. After using the decal process for MEA formation, the Pt/CNT-Al2O3 shows comparable initial performance characteristics to Pt/C, overcoming the lower ORR activity, mainly due to the facile oxygen transport in the cathode catalyst layers fabricated with the CNT-Al2O3 scaffolds. The Pt/CNT-Al2O3 also exhibits much higher durability against carbon corrosion than Pt/C owing to the durable characteristics of CNTs. Systematic analysis of single cell performance for both initial and after degradation is provided to understand the origin of the high initial performance and durable behavior of Pt/CNT-Al2O3-based catalyst layers. This will provide insights into the design of electrocatalysts for high-performance MEAs in PEFCs.

The “I” in us, or the eye on us? Regulatory focus, commitment and derogation of an attractive alternative person

PubMed Central

2017-01-01

When individuals are highly committed to their romantic relationship, they are more likely to engage in pro-relationship maintenance mechanisms. The present research expanded on the notion that commitment redirects self-oriented goals to consider broader relational goals and examined whether commitment interacts with a promotion and prevention focus to activate derogation of attractive alternatives. Three studies used cross-sectional and experimental approaches. Study 1 showed that romantically involved individuals predominantly focused on promotion, but not prevention, reported less initial attraction to an attractive target than single individuals, especially when highly committed to their relationship. Study 2 showed that romantically involved individuals induced in a promotion focus, compared to those in prevention focus, reported less initial attraction, but only when more committed to their relationship. Regardless of regulatory focus manipulation, more committed individuals were also less likely to perceive quality among alternative scenarios and to be attentive to alternative others in general. Finally, Study 3 showed that romantically involved individuals induced in promotion focus and primed with high commitment reported less initial attraction, than those primed with low commitment, or than those induced in prevention focus. Once again, for these latter no differences occurred according to commitment prime. Together, the findings suggest that highly committed promotion focused individuals consider broader relationship goals and activate relationship maintenance behaviors such as derogation of attractive alternatives to promote their relationship. PMID:28319147

Assessment of induced rat mammary tumour response to chemotherapy using the apparent diffusion coefficient of tissue water as determined by diffusion-weighted 1H-NMR spectroscopy in vivo.

PubMed

Lemaire, L; Howe, F A; Rodrigues, L M; Griffiths, J R

1999-03-01

Chemosensitivity of N-methyl-N-nitrosourea-induced rat mammary tumours treated with 5-fluorouracil at a dose of 100 mg kg(-1) i.p. was assessed by using diffusion-weighted 1H-MRS to measure the average diffusion coefficient (ADC) of water in the tumour tissue. ADC measurements prior to any therapy correlated positively with necrotic fraction. Tumours with low initial ADC (< 0.95 x 10(9) m2 s(-1)) showed an increase in ADC 7 days after treatment, whereas tumours with a high initial ADC (> 1.2 x 10(9) m2 s(-1)) showed a decrease. All tumours decreased significantly in volume (P < 0.05) 2, 5 and 7 days after treatment. At day 7 post-treatment, tumours with a high pre-treatment ADC started to regrow. The initial ADC value, as well as changes after treatment predict tumour chemosensitivity, which could be clinically relevant.

A comparative study of biomass integrated gasification combined cycle power systems: Performance analysis.

PubMed

Zang, Guiyan; Tejasvi, Sharma; Ratner, Albert; Lora, Electo Silva

2018-05-01

The Biomass Integrated Gasification Combined Cycle (BIGCC) power system is believed to potentially be a highly efficient way to utilize biomass to generate power. However, there is no comparative study of BIGCC systems that examines all the latest improvements for gasification agents, gas turbine combustion methods, and CO 2 Capture and Storage options. This study examines the impact of recent advancements on BIGCC performance through exergy analysis using Aspen Plus. Results show that the exergy efficiency of these systems is ranged from 22.3% to 37.1%. Furthermore, exergy analysis indicates that the gas turbine with external combustion has relatively high exergy efficiency, and Selexol CO 2 removal method has low exergy destruction. Moreover, the sensitivity analysis shows that the system exergy efficiency is more sensitive to the initial temperature and pressure ratio of the gas turbine, whereas has a relatively weak dependence on the initial temperature and initial pressure of the steam turbine. Copyright © 2018 Elsevier Ltd. All rights reserved.

Population-level interventions in government jurisdictions for dietary sodium reduction: a Cochrane Review.

PubMed

Barberio, Amanda M; Sumar, Nureen; Trieu, Kathy; Lorenzetti, Diane L; Tarasuk, Valerie; Webster, Jacqui; Campbell, Norman R C; McLaren, Lindsay

2017-10-01

Worldwide, excessive salt consumption is common and is a leading cause of high blood pressure. Our objectives were to assess the overall and differential impact (by social and economic indicators) of population-level interventions for dietary sodium reduction in government jurisdictions worldwide. This is a Cochrane systematic review. We searched nine peer-reviewed databases, seven grey literature resources and contacted national programme leaders. We appraised studies using an adapted version of the Cochrane risk of bias tool. To assess impact, we computed the mean change in salt intake (g/day) from before to after intervention. Fifteen initiatives met the inclusion criteria and 10 provided sufficient data for quantitative analysis of impact. Of these, five showed a mean decrease in salt intake from before to after intervention including: China, Finland (Kuopio area), France, Ireland and the UK. When the sample was constrained to the seven initiatives that were multicomponent and incorporated activities of a structural nature (e.g. procurement policy), most (4/7) showed a mean decrease in salt intake. A reduction in salt intake was more apparent among men than women. There was insufficient information to assess differential impact by other social and economic axes. Although many initiatives had methodological strengths, all scored as having a high risk of bias reflecting the observational design. Study heterogeneity was high, reflecting different contexts and initiative characteristics. Population-level dietary sodium reduction initiatives have the potential to reduce dietary salt intake, especially if they are multicomponent and incorporate intervention activities of a structural nature. It is important to consider data infrastructure to permit monitoring of these initiatives. © The Author 2017; all rights reserved. Published by Oxford University Press on behalf of the International Epidemiological Association

Anticipatory Postural Control of Stability during Gait Initiation Over Obstacles of Different Height and Distance Made Under Reaction-Time and Self-Initiated Instructions.

PubMed

Yiou, Eric; Artico, Romain; Teyssedre, Claudine A; Labaune, Ombeline; Fourcade, Paul

2016-01-01

Despite the abundant literature on obstacle crossing in humans, the question of how the central nervous system (CNS) controls postural stability during gait initiation with the goal to clear an obstacle remains unclear. Stabilizing features of gait initiation include anticipatory postural adjustments (APAs) and lateral swing foot placement. To answer the above question, 14 participants initiated gait as fast as possible in three conditions of obstacle height, three conditions of obstacle distance and one obstacle-free (control) condition. Each of these conditions was performed with two levels of temporal pressure: reaction-time (high-pressure) and self-initiated (low-pressure) movements. A mechanical model of the body falling laterally under the influence of gravity and submitted to an elastic restoring force is proposed to assess the effect of initial (foot-off) center-of-mass position and velocity (or "initial center-of-mass set") on the stability at foot-contact. Results showed that the anticipatory peak of mediolateral (ML) center-of-pressure shift, the initial ML center-of-mass velocity and the duration of the swing phase, of gait initiation increased with obstacle height, but not with obstacle distance. These results suggest that ML APAs are scaled with swing duration in order to maintain an equivalent stability across experimental conditions. This statement is strengthened by the results obtained with the mechanical model, which showed how stability would be degraded if there was no adaptation of the initial center-of-mass set to swing duration. The anteroposterior (AP) component of APAs varied also according to obstacle height and distance, but in an opposite way to the ML component. Indeed, results showed that the anticipatory peak of backward center-of-pressure shift and the initial forward center-of-mass set decreased with obstacle height, probably in order to limit the risk to trip over the obstacle, while the forward center-of-mass velocity at foot-off increased with obstacle distance, allowing a further step to be taken. These effects of obstacle height and distance were globally similar under low and high-temporal pressure. Collectively, these findings imply that the CNS is able to predict the potential instability elicited by the obstacle clearance and that it scales the spatiotemporal parameters of APAs accordingly.

Anticipatory Postural Control of Stability during Gait Initiation Over Obstacles of Different Height and Distance Made Under Reaction-Time and Self-Initiated Instructions

PubMed Central

Yiou, Eric; Artico, Romain; Teyssedre, Claudine A.; Labaune, Ombeline; Fourcade, Paul

2016-01-01

Despite the abundant literature on obstacle crossing in humans, the question of how the central nervous system (CNS) controls postural stability during gait initiation with the goal to clear an obstacle remains unclear. Stabilizing features of gait initiation include anticipatory postural adjustments (APAs) and lateral swing foot placement. To answer the above question, 14 participants initiated gait as fast as possible in three conditions of obstacle height, three conditions of obstacle distance and one obstacle-free (control) condition. Each of these conditions was performed with two levels of temporal pressure: reaction-time (high-pressure) and self-initiated (low-pressure) movements. A mechanical model of the body falling laterally under the influence of gravity and submitted to an elastic restoring force is proposed to assess the effect of initial (foot-off) center-of-mass position and velocity (or “initial center-of-mass set”) on the stability at foot-contact. Results showed that the anticipatory peak of mediolateral (ML) center-of-pressure shift, the initial ML center-of-mass velocity and the duration of the swing phase, of gait initiation increased with obstacle height, but not with obstacle distance. These results suggest that ML APAs are scaled with swing duration in order to maintain an equivalent stability across experimental conditions. This statement is strengthened by the results obtained with the mechanical model, which showed how stability would be degraded if there was no adaptation of the initial center-of-mass set to swing duration. The anteroposterior (AP) component of APAs varied also according to obstacle height and distance, but in an opposite way to the ML component. Indeed, results showed that the anticipatory peak of backward center-of-pressure shift and the initial forward center-of-mass set decreased with obstacle height, probably in order to limit the risk to trip over the obstacle, while the forward center-of-mass velocity at foot-off increased with obstacle distance, allowing a further step to be taken. These effects of obstacle height and distance were globally similar under low and high-temporal pressure. Collectively, these findings imply that the CNS is able to predict the potential instability elicited by the obstacle clearance and that it scales the spatiotemporal parameters of APAs accordingly. PMID:27656138

A facile one-step approach for the fabrication of polypyrrole nanowire/carbon fiber hybrid electrodes for flexible high performance solid-state supercapacitors

NASA Astrophysics Data System (ADS)

Huang, Sanqing; Han, Yichuan; Lyu, Siwei; Lin, Wenzhen; Chen, Peishan; Fang, Shaoli

2017-10-01

Wearable electronics are in high demand, requiring that all the components are flexible. Here we report a facile approach for the fabrication of flexible polypyrrole nanowire (NPPy)/carbon fiber (CF) hybrid electrodes with high electrochemical activity using a low-cost, one-step electrodeposition method. The structure of the NPPy/CF electrodes can be easily controlled by the applied electrical potential and electrodeposition time. Our NPPy/CF-based electrodes showed high flexibility, conductivity, and stability, making them ideal for flexible all-solid-state fiber supercapacitors. The resulting NPPy/CF-based supercapacitors provided a high specific capacitance of 148.4 F g-1 at 0.128 A g-1, which is much higher than for supercapacitors based on polypyrrole film/CF (38.3 F g-1) and pure CF (0.6 F g-1) under the same conditions. The NPPy/CF-based supercapacitors also showed high bending and cycling stability, retaining 84% of the initial capacitance after 500 bending cycles, and 91% of the initial capacitance after 5000 charge/discharge cycles.

A facile one-step approach for the fabrication of polypyrrole nanowire/carbon fiber hybrid electrodes for flexible high performance solid-state supercapacitors.

PubMed

Huang, Sanqing; Han, Yichuan; Lyu, Siwei; Lin, Wenzhen; Chen, Peishan; Fang, Shaoli

2017-10-27

Wearable electronics are in high demand, requiring that all the components are flexible. Here we report a facile approach for the fabrication of flexible polypyrrole nanowire (NPPy)/carbon fiber (CF) hybrid electrodes with high electrochemical activity using a low-cost, one-step electrodeposition method. The structure of the NPPy/CF electrodes can be easily controlled by the applied electrical potential and electrodeposition time. Our NPPy/CF-based electrodes showed high flexibility, conductivity, and stability, making them ideal for flexible all-solid-state fiber supercapacitors. The resulting NPPy/CF-based supercapacitors provided a high specific capacitance of 148.4 F g -1 at 0.128 A g -1 , which is much higher than for supercapacitors based on polypyrrole film/CF (38.3 F g -1 ) and pure CF (0.6 F g -1 ) under the same conditions. The NPPy/CF-based supercapacitors also showed high bending and cycling stability, retaining 84% of the initial capacitance after 500 bending cycles, and 91% of the initial capacitance after 5000 charge/discharge cycles.

Late-Time Mixing Sensitivity to Initial Broadband Surface Roughness in High-Energy-Density Shear Layers

DOE PAGES

Flippo, K. A.; Doss, F. W.; Kline, J. L.; ...

2016-11-23

While using a large volume high-energy-density fluid shear experiment ( 8.5 cm 3 ) at the National Ignition Facility, we have demonstrated for the first time the ability to significantly alter the evolution of a supersonic sheared mixing layer by controlling the initial conditions of that layer. Furthermore, by altering the initial surface roughness of the tracer foil, we demonstrate the ability to transition the shear mixing layer from a highly ordered system of coherent structures to a randomly ordered system with a faster growing mix layer, indicative of strong mixing in the layer at a temperature of severalmore » tens of electron volts and at near solid density. Moreover, simulations using a turbulent-mix model show good agreement with the experimental results and poor agreement without turbulent mix.« less

Strong minor groove base conservation in sequence logos implies DNA distortion or base flipping during replication and transcription initiation.

PubMed

Schneider, T D

2001-12-01

The sequence logo for DNA binding sites of the bacteriophage P1 replication protein RepA shows unusually high sequence conservation ( approximately 2 bits) at a minor groove that faces RepA. However, B-form DNA can support only 1 bit of sequence conservation via contacts into the minor groove. The high conservation in RepA sites therefore implies a distorted DNA helix with direct or indirect contacts to the protein. Here I show that a high minor groove conservation signature also appears in sequence logos of sites for other replication origin binding proteins (Rts1, DnaA, P4 alpha, EBNA1, ORC) and promoter binding proteins (sigma(70), sigma(D) factors). This finding implies that DNA binding proteins generally use non-B-form DNA distortion such as base flipping to initiate replication and transcription.

Electrical treeing behaviors in silicone rubber under an impulse voltage considering high temperature

NASA Astrophysics Data System (ADS)

Yunxiao, ZHANG; Yuanxiang, ZHOU; Ling, ZHANG; Zhen, LIN; Jie, LIU; Zhongliu, ZHOU

2018-05-01

In this paper, work was conducted to reveal electrical tree behaviors (initiation and propagation) of silicone rubber (SIR) under an impulse voltage with high temperature. Impulse frequencies ranging from 10 Hz to 1 kHz were applied and the temperature was controlled between 30 °C and 90 °C. Experimental results show that tree initiation voltage decreases with increasing pulse frequency, and the descending amplitude is different in different frequency bands. As the pulse frequency increases, more frequent partial discharges occur in the channel, increasing the tree growth rate and the final shape intensity. As for temperature, the initiation voltage decreases and the tree shape becomes denser as the temperature gets higher. Based on differential scanning calorimetry results, we believe that partial segment relaxation of SIR at high temperature leads to a decrease in the initiation voltage. However, the tree growth rate decreases with increasing temperature. Carbonization deposition in the channel under high temperature was observed under microscope and proven by Raman analysis. Different tree growth models considering tree channel characteristics are proposed. It is believed that increasing the conductivity in the tree channel restrains the partial discharge, holding back the tree growth at high temperature.

Serotonin Mediates a Learned Increase in Attraction to High Concentrations of Benzaldehyde in Aged "C. elegans"

ERIC Educational Resources Information Center

Tsui, David; van der Kooy, Derek

2008-01-01

We utilized olfactory-mediated chemotaxis in "Caenorhabditis elegans" to examine the effect of aging on information processing and animal behavior. Wild-type (N2) young adults (day 4) initially approach and eventually avoid a point source of benzaldehyde. Aged adult animals (day 7) showed a stronger initial approach and a delayed avoidance to…

Are Persistent Early Onset Child Conduct Problems Predicted by the Trajectories and Initial Levels of Discipline Practices?

ERIC Educational Resources Information Center

Lorber, Michael F.; Slep, Amy M. Smith

2015-01-01

In the present investigation we focused on 2 broad sets of questions: Do parental overreactivity, laxness, and corporal punishment show evidence of normative change in early to middle childhood? Are persistently elevated child conduct problems (CPs) associated with deviations from normative changes in, as well as high initial levels of, discipline…

High-predation habitats affect the social dynamics of collective exploration in a shoaling fish.

PubMed

Ioannou, Christos C; Ramnarine, Indar W; Torney, Colin J

2017-05-01

Collective decisions play a major role in the benefits that animals gain from living in groups. Although the mechanisms of how groups collectively make decisions have been extensively researched, the response of within-group dynamics to ecological conditions is virtually unknown, despite adaptation to the environment being a cornerstone in biology. We investigate how within-group interactions during exploration of a novel environment are shaped by predation, a major influence on the behavior of prey species. We tested guppies ( Poecilia reticulata ) from rivers varying in predation risk under controlled laboratory conditions and find the first evidence of differences in group interactions between animals adapted to different levels of predation. Fish from high-predation habitats showed the strongest negative relationship between initiating movements and following others, which resulted in less variability in the total number of movements made between individuals. This relationship between initiating movements and following others was associated with differentiation into initiators and followers, which was only observed in fish from high-predation rivers. The differentiation occurred rapidly, as trials lasted 5 min, and was related to shoal cohesion, where more diverse groups from high-predation habitats were more cohesive. Our results show that even within a single species over a small geographical range, decision-making in a social context can vary with local ecological factors.

Initial segment Kv2.2 channels mediate a slow delayed rectifier and maintain high frequency action potential firing in medial nucleus of the trapezoid body neurons

PubMed Central

Johnston, Jamie; Griffin, Sarah J; Baker, Claire; Skrzypiec, Anna; Chernova, Tatanya; Forsythe, Ian D

2008-01-01

The medial nucleus of the trapezoid body (MNTB) is specialized for high frequency firing by expression of Kv3 channels, which minimize action potential (AP) duration, and Kv1 channels, which suppress multiple AP firing, during each calyceal giant EPSC. However, the outward K+ current in MNTB neurons is dominated by another unidentified delayed rectifier. It has slow kinetics and a peak conductance of ∼37 nS; it is half-activated at −9.2 ± 2.1 mV and half-inactivated at −35.9 ± 1.5 mV. It is blocked by several non-specific potassium channel antagonists including quinine (100 μm) and high concentrations of extracellular tetraethylammonium (TEA; IC50 = 11.8 mm), but no specific antagonists were found. These characteristics are similar to recombinant Kv2-mediated currents. Quantitative RT-PCR showed that Kv2.2 mRNA was much more prevalent than Kv2.1 in the MNTB. A Kv2.2 antibody showed specific staining and Western blots confirmed that it recognized a protein ∼110 kDa which was absent in brainstem tissue from a Kv2.2 knockout mouse. Confocal imaging showed that Kv2.2 was highly expressed in axon initial segments of MNTB neurons. In the absence of a specific antagonist, Hodgkin–Huxley modelling of voltage-gated conductances showed that Kv2.2 has a minor role during single APs (due to its slow activation) but assists recovery of voltage-gated sodium channels (Nav) from inactivation by hyperpolarizing interspike potentials during repetitive AP firing. Current-clamp recordings during high frequency firing and characterization of Nav inactivation confirmed this hypothesis. We conclude that Kv2.2-containing channels have a distinctive initial segment location and crucial function in maintaining AP amplitude by regulating the interspike potential during high frequency firing. PMID:18511484

Sensitivity of mRNA Translation

PubMed Central

Poker, Gilad; Margaliot, Michael; Tuller, Tamir

2015-01-01

Using the dynamic mean-field approximation of the totally asymmetric simple exclusion process (TASEP), we investigate the effect of small changes in the initiation, elongation, and termination rates along the mRNA strand on the steady-state protein translation rate. We show that the sensitivity of mRNA translation is equal to the sensitivity of the maximal eigenvalue of a symmetric, nonnegative, tridiagonal, and irreducible matrix. This leads to new analytical results as well as efficient numerical schemes that are applicable for large-scale models. Our results show that in the usual endogenous case, when initiation is more rate-limiting than elongation, the sensitivity of the translation rate to small mutations rapidly increases towards the 5′ end of the ORF. When the initiation rate is high, as may be the case for highly expressed and/or heterologous optimized genes, the maximal sensitivity is with respect to the elongation rates at the middle of the mRNA strand. We also show that the maximal possible effect of a small increase/decrease in any of the rates along the mRNA is an increase/decrease of the same magnitude in the translation rate. These results are in agreement with previous molecular evolutionary and synthetic biology experimental studies. PMID:26238363

Mutual influences between partners' hormones shape conflict dialog and relationship duration at the initiation of romantic love.

PubMed

Schneiderman, Inna; Kanat-Maymon, Yaniv; Zagoory-Sharon, Orna; Feldman, Ruth

2014-01-01

Early-stage romantic love involves reorganization of neurohormonal systems and behavioral patterns marked by mutual influences between the partners' physiology and behavior. Guided by the biobehavioral synchrony conceptual frame, we tested bidirectional influences between the partners' hormones and conflict behavior at the initiation of romantic love. Participants included 120 new lovers (60 couples) and 40 singles. Plasma levels of five affiliation and stress-related hormones were assessed: oxytocin (OT), prolactin (PRL), testosterone (T), cortisol (CT), and dehydroepiandrosterone sulfate (DHEAS). Couples were observed in conflict interaction coded for empathy and hostility. CT and DHEAS showed direct actor effects: higher CT and DHEAS predicted greater hostility. OT showed direct partner effects: individuals whose partners had higher OT showed greater empathy. T and CT showed combined actor-partner effects. High T predicted greater hostility only when partner also had high T, but lower hostility when partner had low T. Similarly, CT predicted low empathy only in the context of high partner's CT. Mediational analysis indicated that combined high CT in both partners was associated with relationship breakup as mediated by decrease in empathy. Findings demonstrate the mutual influences between hormones and behavior within an attachment bond and underscore the dynamic, co-regulated, and systemic nature of pair-bond formation in humans.

Low temperature rf sputtering deposition of (Ba, Sr) TiO3 thin film with crystallization enhancement by rf power supplied to the substrate

NASA Astrophysics Data System (ADS)

Yoshimaru, Masaki; Takehiro, Shinobu; Abe, Kazuhide; Onoda, Hiroshi

2005-05-01

The (Ba, Sr) TiO3 thin film deposited by radio frequency (rf) sputtering requires a high deposition temperature near 500 °C to realize a high relative dielectric constant over of 300. For example, the film deposited at 330 °C contains an amorphous phase and shows a low relative dielectric constant of less than 100. We found that rf power supplied not only to the (Ba, Sr) TiO3 sputtering target, but also to the substrate during the initial step of film deposition, enhanced the crystallization of the (Ba, Sr) TiO3 film drastically and realized a high dielectric constant of the film even at low deposition temperatures near 300 °C. The 50-nm-thick film with only a 10 nm initial layer deposited with the substrate rf biasing is crystallized completely and shows a high relative dielectric constant of 380 at the deposition temperature of 330 °C. The (Ba, Sr) TiO3 film deposited at higher temperatures (upwards of 400 °C) shows <110> preferred orientation, while the film deposited at 330 °C with the 10 nm initial layer shows a <111> preferred orientation on a <001>-oriented ruthenium electrode. The unit cell of (Ba, Sr) TiO3 (111) plane is similar to that of ruthenium (001) plane. We conclude that the rf power supplied to the substrate causes ion bombardments on the (Ba, Sr) TiO3 film surface, which assists the quasiepitaxial growth of (Ba, Sr) TiO3 film on the ruthenium electrode at low temperatures of less than 400 °C.

Do cosmic ray air showers initiate lightning?: A statistical analysis of cosmic ray air showers and lightning mapping array data

NASA Astrophysics Data System (ADS)

Hare, B. M.; Dwyer, J. R.; Winner, L. H.; Uman, M. A.; Jordan, D. M.; Kotovsky, D. A.; Caicedo, J. A.; Wilkes, R. A.; Carvalho, F. L.; Pilkey, J. T.; Ngin, T. K.; Gamerota, W. R.; Rassoul, H. K.

2017-08-01

It has been argued in the technical literature, and widely reported in the popular press, that cosmic ray air showers (CRASs) can initiate lightning via a mechanism known as relativistic runaway electron avalanche (RREA), where large numbers of high-energy and low-energy electrons can, somehow, cause the local atmosphere in a thundercloud to transition to a conducting state. In response to this claim, other researchers have published simulations showing that the electron density produced by RREA is far too small to be able to affect the conductivity in the cloud sufficiently to initiate lightning. In this paper, we compare 74 days of cosmic ray air shower data collected in north central Florida during 2013-2015, the recorded CRASs having primary energies on the order of 1016 eV to 1018 eV and zenith angles less than 38°, with Lightning Mapping Array (LMA) data, and we show that there is no evidence that the detected cosmic ray air showers initiated lightning. Furthermore, we show that the average probability of any of our detected cosmic ray air showers to initiate a lightning flash can be no more than 5%. If all lightning flashes were initiated by cosmic ray air showers, then about 1.6% of detected CRASs would initiate lightning; therefore, we do not have enough data to exclude the possibility that lightning flashes could be initiated by cosmic ray air showers.

Impact of the springtime Himalayan-Tibetan Plateau on the onset on the Indian summer monsoon in coupled forecasts

NASA Astrophysics Data System (ADS)

Orsolini, Yvan; Senan, Retish; Weisheimer, Antje; Vitart, Frederic; Balsamo, Gianpaolo; Doblas-Reyes, Francisco; Stockdale, Timothy; Dutra, Emanuel

2016-04-01

The springtime snowpack over the Himalayan-Tibetan Plateau (HTP) region has long been suggested to be an influential factor on the onset of the Indian summer monsoon. In the frame of the SPECS project, we have assessed the impact of realistic snow initialization in springtime over HTP on the onset of the Indian summer monsoon. We examine a suite of coupled ocean-atmosphere 4-month ensemble reforecasts made at the European Centre for Medium-Range Weather Forecasts (ECMWF), using the Seasonal Forecasting System 4. The reforecasts were initialized on 1 April every year for the period 1981-2010. In these seasonal reforecasts, the snow is initialized "realistically" with ERA-Interim/Land Reanalysis. In addition, we carried out an additional set of forecasts, identical in all aspects except that initial conditions for snow-related land surface variables over the HTP region are randomized. We show that high snow depth over HTP influences the meridional tropospheric temperature gradient reversal that marks the monsoon onset. Composite difference based on a normalized HTP snow index reveal that, in high snow years, (i) the onset is delayed by about 8 days, and (ii) negative precipitation anomalies and warm surface conditions prevail over India. We show that about half of this delay can be attributed to the realistic initialization of snow over the HTP region. We further demonstrate that high April snow depths over HTP are not uniquely influenced by either the El Nino-Southern Oscillation, the Indian Ocean Dipole or the North Atlantic Oscillation.

Adsorption of malachite green dye from aqueous solution on the bamboo leaf ash

NASA Astrophysics Data System (ADS)

Kuntari, Priwidyanjati, Dessyntha Anggiani

2017-12-01

Bamboo leaf ash has been developed as an adsorbent material for removal malachite green from aqueous solution. Adsorption parameters have studied are contact time and initial pH. The effect of contact time and pH were examined in the batch adsorption processes. The physicochemical characters of bamboo leaf ash were investigated by using X-Ray Diffraction (XRD) and FT-IR spectroscopy. Malachite green concentration was determined by UV-Vis spectrophotometer. FT-IR spectrogram of bamboo leaf ash shows that typical fingerprint of adsorbent material with Si-O-Si or Al-O-Al group. The X-ray diffractograms of bamboo leaf ash show that adsorbent material has a highly amorphous nature. The percentage of adsorption was showed raised with increasing contact time. The optimum removal of malachite green when the initial dye concentration, initial pH, weight of adsorbent and contact time was 20 mg/L, 7, 0.25 g and 75 minutes respectively.

The Effect of Porosity on Fatigue of Die Cast AM60

NASA Astrophysics Data System (ADS)

Yang, Zhuofei; Kang, Jidong; Wilkinson, David S.

2016-07-01

AM60 high-pressure die castings are known to contain significant porosity which can affect fatigue life. We have studied this using samples drawn from prototype AM60 shock towers by conducting strain-controlled fatigue tests accompanied by X-ray computed tomography analysis. The results show that the machined surface is the preferential location for fatigue crack development, with pores close to these surfaces serving as initiation sites. Fatigue life shows a strong inverse correlation with the size of the fatigue-crack-initiating pore. Pore shape and pore orientation also influence the response. A supplemental study on surface roughness shows that porosity is the dominant factor in fatigue. Tomography enables the link between porosity and fatigue crack initiation to be clearly identified. These data are complemented by SEM observations of the fracture surfaces which are generally flat and full of randomly oriented serration patterns but without long-range fatigue striations.

High-Speed Rolling of AZ31 Magnesium Alloy Having Different Initial Textures

NASA Astrophysics Data System (ADS)

Onuki, Yusuke; Hara, Kenichiro; Utsunomiya, Hiroshi; Szpunar, Jerzy A.

2015-02-01

It is known that magnesium alloys can be rolled up to a large thickness reduction and develop a unique texture when the rolling speed is high (>1000 m/min). In order to understand the texture formation mechanism during high-strain-rate deformation, high-speed rolling of AZ31 magnesium alloy samples having different initial textures was conducted. The main components of the textures after the rolling were the RD-split basal, which consisted of 10°-20° inclining basal poles from the normal direction toward the rolling direction of the sheet, regardless of the different initial textures. With preheating at 473 K, all the samples were rolled without cracking while all were cracked when preheating was not applied. The optical micrographs and EBSD measurements showed a significant amount of twins and the cracks that developed along the shear bands consisted with laminated twins. Based on the texture simulation using the visco-plastic self-consistent model, it is concluded that the rapid development of the RD-split basal component from the initial basal alignment along the transverse direction was attributable to the tension twinning, The effect of the initial texture on the crack formation can be explained by the activation of the twinning system.

More flowers or new cladodes? Environmental correlates and biological consequences of sexual reproduction in a Sonoran Desert prickly pear cactus, Opuntia engelmannii

USGS Publications Warehouse

Bowers, Janice E.

1996-01-01

Should a platyopuntia expend all aerolar meristems in flower production, now new cladodes could be produced, and further reproductive effort and vegetative growth would cease. To investigate the trade-off between flower and cladode production, the numbers of flowers, fruits, and cladodes were monitored for 4 years on 30 Opuntia engelmannii Salm-Dyek, plants on Tumamoc Hill, Tucson, Arizona. Plant size controlled the number of flowers initiated each spring. The proportion of flowers that developed (i.e., did not abort) was perhaps determined by December-February rainfall in the months before bloom, with more being developed in the wettest years. Models based on different ratios of initiated cladodes to initiated flowers demonstrated that continued high investment in flowers and fruits would eventually terminate reproduction altogether; therefore periods of high sexual reproduction should alternate with periods of high vegetative growth. In the first 3 years of this study, the ratio of new cladodes to initiated flowers was low, showing a high investment in sexual reproduction. As suggested by the model, the population recouped this investment in the fourth year, when the number of new cladodes was nearly 3 times the 1992-1994 mean, and the number of initiated flowers was only 73% of the 3-year mean.

Imaging of high-amylose starch tablets. 3. Initial diffusion and temperature effects.

PubMed

Thérien-Aubin, Héloïse; Baille, Wilms E; Zhu, Xiao Xia; Marchessault, Robert H

2005-01-01

The penetration of water into cross-linked high amylose starch tablets was studied at different temperatures by nuclear magnetic resonance (NMR) imaging, which follows the changes occurring at the surface and inside the starch tablets during swelling. It was found that the swelling was anisotropic, whereas water diffusion was almost isotropic. The water proton image profiles at the initial stage of water penetration were used to calculate the initial diffusion coefficient. The swelling and water concentration gradients in this controlled release system show significant temperature dependence. Diffusion behavior changed from Fickian to Case II diffusion with increasing temperature. The observed phenomena are attributed to the gelatinization of starch and the pseudo-cross-linking effect of double helix formation.

32-channel pyrometer with high dynamic range for studies of shocked nanothermites

NASA Astrophysics Data System (ADS)

Bassett, Will P.; Dlott, Dana D.

2017-01-01

A 32-channel optical pyrometer has been developed for studying temperature dynamics of shock-initiated reactive materials with one nanosecond time resolution and high dynamic range. The pyrometer consists of a prism spectrograph which directs the spectrally-resolved emission to 32 fiber optics and 32 photomultiplier tubes and digitizers. Preliminary results show shock-initiated reactions of a nanothermite composite, nano CuO/Al in nitrocellulose binder, consists of three stages. The first stage occurred at 30 ns, right after the shock unloaded, the second stage at 100 ns and the third at 1 μs, and the temperatures ranged from 2100K to 3000K. Time-resolved emission spectra suggest hot spots formed during shock unloading, which initiated the bulk thermite/nitrocellulose reaction.

Accelerating the development of formal thinking in middle and high school students II: Postproject effects on science achievement

NASA Astrophysics Data System (ADS)

Shayer, Michael; Adey, Philip S.

A one-year lag was found between the effect of an intervention intended to promote formal operational thinking in students initially 11 or 12 years of age and the appearance of substantial science achievement in the experimental groups. A one-year lag was also reported on cognitive development: Whereas at the end of the two-year intervention the experimental groups were up to 0.9 ahead of the control groups, one year later the differential on Piagetian measures had disappeared, but the experimentals now showed better science achievement of even greater magnitude. Although the control groups showed normal distribution both on science achievement and cognitive development, the experimental groups showed bi- or trimodal distribution. Between one-half and one-quarter of the students involved in the experiment in different groups showed effects of the order of 2 both on cognitive development and science achievement; some students appeared unaffected (compared with the controls), and others demonstrated modest effects on science achievement. An age/gender interaction is reported: the most substantial effects were found in boys initially aged 12+ and girls initially 11+. The only group to show no effects was boys initially aged 11+. It is suggested that the intervention methods may have favored the abstract analytical learning style as described by Cohen 1986.

POST-OUTBURST RADIO OBSERVATIONS OF THE HIGH MAGNETIC FIELD PULSAR PSR J1119-6127

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

Majid, Walid A.; Pearlman, Aaron B.; Dobreva, Tatyana

We have carried out high-frequency radio observations of the high magnetic field pulsar PSR J1119-6127 following its recent X-ray outburst. While initial observations showed no evidence of significant radio emission, subsequent observations detected pulsed emission across a large frequency band. In this Letter, we report on the initial disappearance of the pulsed emission and its prompt reactivation and dramatic evolution over several months of observation. The periodic pulse profile at S -band (2.3 GHz) after reactivation exhibits a multi-component emission structure, while the simultaneous X -band (8.4 GHz) profile shows a single emission peak. Single pulses were also detected atmore » S -band near the main emission peaks. We present measurements of the spectral index across a wide frequency bandwidth, which captures the underlying changes in the radio emission profile of the neutron star. The high-frequency radio detection, unusual emission profile, and observed variability suggest similarities with magnetars, which may independently link the high-energy outbursts to magnetar-like behavior.« less

Associations of Neighborhood and Family Factors with Trajectories of Physical and Social Aggression During Adolescence

PubMed Central

Karriker-Jaffe, Katherine J.; Foshee, Vangie A.; Ennett, Susan T.; Suchindran, Chirayath

2013-01-01

Adolescents develop within multiple contexts that synergistically influence their behavior and health. To understand the simultaneous influence of neighborhood and family contexts on adolescents, this study examined relationships of neighborhood socioeconomic disadvantage, neighborhood social disorganization, family conflict, parent-child bonding and parental control with trajectories of physical and social aggression. The sample included 5,118 adolescents between ages 11 and 18 (50% female, 52% Caucasian) living in predominantly rural areas. Multilevel growth curve models showed an interaction between neighborhood disadvantage, family conflict and gender on the physical aggression trajectories. The interaction suggested more rapid processes of both increase in and desistance from physical aggression over time for boys with high neighborhood disadvantage and high family conflict, as well as a higher starting point, more gradual increase and slower process of desistance over time for girls in similar neighborhood and family contexts. Less parent-child bonding and less parental control also were associated with higher initial levels of physical aggression. For social aggression, an interaction between family conflict and gender showed girls with high family conflict had the highest initial levels of social aggression, with a more gradual increase over time for these girls compared to their male counterparts in high-conflict families or their female counterparts in low-conflict families. Less parent-child bonding was associated with higher initial levels and a faster increase over time of social aggression, and less parental control was associated with higher initial levels of social aggression. The findings suggest early family-based interventions may help prevent perpetration of both physical and social aggression during adolescence. PMID:23054352

Associations of neighborhood and family factors with trajectories of physical and social aggression during adolescence.

PubMed

Karriker-Jaffe, Katherine J; Foshee, Vangie A; Ennett, Susan T; Suchindran, Chirayath

2013-06-01

Adolescents develop within multiple contexts that synergistically influence their behavior and health. To understand the simultaneous influence of neighborhood and family contexts on adolescents, this study examined relationships of neighborhood socioeconomic disadvantage, neighborhood social disorganization, family conflict, parent-child bonding and parental control with trajectories of physical and social aggression. The sample included 5,118 adolescents between ages 11 and 18 (50% female, 52% Caucasian) living in predominantly rural areas. Multilevel growth curve models showed an interaction between neighborhood disadvantage, family conflict and gender on the physical aggression trajectories. The interaction suggested more rapid processes of both increase in and desistance from physical aggression over time for boys with high neighborhood disadvantage and high family conflict, as well as a higher starting point, more gradual increase and slower process of desistance over time for girls in similar neighborhood and family contexts. Less parent-child bonding and less parental control also were associated with higher initial levels of physical aggression. For social aggression, an interaction between family conflict and gender showed girls with high family conflict had the highest initial levels of social aggression, with a more gradual increase over time for these girls compared to their male counterparts in high-conflict families or their female counterparts in low-conflict families. Less parent-child bonding was associated with higher initial levels and a faster increase over time of social aggression, and less parental control was associated with higher initial levels of social aggression. The findings suggest early family-based interventions may help prevent perpetration of both physical and social aggression during adolescence.

Evidence that abnormal grain growth precedes fatigue crack initiation in nanocrystalline Ni-Fe

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

Furnish, Timothy A.; Bufford, Daniel C.; Ren, Fang

Prior studies on the high-cycle fatigue behavior of nanocrystalline metals have shown that fatigue fracture is associated with abnormal grain growth (AGG). However, those previous studies have been unable to determine if AGG precedes fatigue crack initiation, or vice-versa. The present study shows that AGG indeed occurs prior to crack formation in nanocrystalline Ni-Fe by using a recently developed synchrotron X-ray diffraction modality that has been adapted for in-situ analysis. The technique allows fatigue tests to be interrupted at the initial signs of the AGG process, and subsequent microscopy reveals the precursor damage state preceding crack initiation.

Evidence that abnormal grain growth precedes fatigue crack initiation in nanocrystalline Ni-Fe

DOE PAGES

Furnish, Timothy A.; Bufford, Daniel C.; Ren, Fang; ...

2018-09-06

Prior studies on the high-cycle fatigue behavior of nanocrystalline metals have shown that fatigue fracture is associated with abnormal grain growth (AGG). However, those previous studies have been unable to determine if AGG precedes fatigue crack initiation, or vice-versa. The present study shows that AGG indeed occurs prior to crack formation in nanocrystalline Ni-Fe by using a recently developed synchrotron X-ray diffraction modality that has been adapted for in-situ analysis. The technique allows fatigue tests to be interrupted at the initial signs of the AGG process, and subsequent microscopy reveals the precursor damage state preceding crack initiation.

Evaluating average and atypical response in radiation effects simulations

NASA Astrophysics Data System (ADS)

Weller, R. A.; Sternberg, A. L.; Massengill, L. W.; Schrimpf, R. D.; Fleetwood, D. M.

2003-12-01

We examine the limits of performing single-event simulations using pre-averaged radiation events. Geant4 simulations show the necessity, for future devices, to supplement current methods with ensemble averaging of device-level responses to physically realistic radiation events. Initial Monte Carlo simulations have generated a significant number of extremal events in local energy deposition. These simulations strongly suggest that proton strikes of sufficient energy, even those that initiate purely electronic interactions, can initiate device response capable in principle of producing single event upset or microdose damage in highly scaled devices.

Effect of initial moisture content on the in-vessel composting under air pressure of organic fraction of municipal solid waste in Morocco.

PubMed

Makan, Abdelhadi; Assobhei, Omar; Mountadar, Mohammed

2013-01-03

This study aimed to evaluate the effect of initial moisture content on the in-vessel composting under air pressure of organic fraction of municipal solid waste in Morocco in terms of internal temperature, produced gases quantity, organic matter conversion rate, and the quality of the final composts.For this purpose, in-vessel bioreactor was designed and used to evaluate both appropriate initial air pressure and appropriate initial moisture content for the composting process. Moreover, 5 experiments were carried out within initial moisture content of 55%, 65%, 70%, 75% and 85%. The initial air pressure and the initial moisture content of the mixture showed a significant effect on the aerobic composting. The experimental results demonstrated that for composting organic waste, relatively high moisture contents are better at achieving higher temperatures and retaining them for longer times.This study suggested that an initial moisture content of around 75%, under 0.6 bar, can be considered as being suitable for efficient composting of organic fraction of municipal solid waste. These last conditions, allowed maximum value of temperature and final composting product with good physicochemical properties as well as higher organic matter degradation and higher gas production. Moreover, final compost obtained showed good maturity levels and can be used for agricultural applications.

Joint Attention Initiation with and without Positive Affect: Risk Group Differences and Associations with ASD Symptoms

PubMed Central

Gangi, Devon N.; Ibañez, Lisa V.; Messinger, Daniel S.

2014-01-01

Infants at risk for Autism Spectrum Disorders (ASD) may have difficulty integrating smiles into initiating joint attention (IJA) bids. A specific IJA pattern, anticipatory smiling, may communicate preexisting positive affect when an infant smiles at an object and then turns the smile toward the social partner. We compared the development of anticipatory smiling at 8, 10, and 12 months in infant siblings of children with ASD (high-risk siblings) and without ASD (low-risk siblings). High-risk siblings produced less anticipatory smiling than low-risk siblings, suggesting early differences in communicating preexisting positive affect. While early anticipatory smiling distinguished the risk groups, IJA not accompanied by smiling best predicted later severity of ASD-related behavioral characteristics among high-risk siblings. High-risk infants appear to show lower levels of motivation to share positive affect with others. However, facility with initiating joint attention in the absence of a clear index of positive affective motivation appears to be central to the prediction of ASD symptoms. PMID:24281421

An Evaluation of 25 Selected ToxCast Chemicals in Medium-Throughput Assays to Detect Genotoxicity

EPA Science Inventory

ABSTRACTToxCast is a multi-year effort to develop a cost-effective approach for the US EPA to prioritize chemicals for toxicity testing. Initial evaluation of more than 500 high-throughput (HT) microwell-based assays without metabolic activation showed that most lacked high speci...

Small High Schools on a Larger Scale: The First Three Years of the Chicago High School Redesign Initiative. Research Report

ERIC Educational Resources Information Center

Kahne, Joseph E.; Sporte, Susan E.; de la Torre, Marisa

2006-01-01

Increasingly, researchers, policymakers, school leaders, and concerned citizens are recognizing that high schools in the United States are in need of major reform. Current research shows that high schools are not preparing students for college, work, or life, and that they are leading to increased alienation among students. In a much-noted speech…

Gone in a Flash

NASA Image and Video Library

2005-07-04

This image shows the initial ejecta that resulted when NASA Deep Impact probe collided with comet Tempel 1 on July 3, 2005. It was taken by the spacecraft high-resolution camera 13 seconds after impact.

Experimental magic state distillation for fault-tolerant quantum computing.

PubMed

Souza, Alexandre M; Zhang, Jingfu; Ryan, Colm A; Laflamme, Raymond

2011-01-25

Any physical quantum device for quantum information processing (QIP) is subject to errors in implementation. In order to be reliable and efficient, quantum computers will need error-correcting or error-avoiding methods. Fault-tolerance achieved through quantum error correction will be an integral part of quantum computers. Of the many methods that have been discovered to implement it, a highly successful approach has been to use transversal gates and specific initial states. A critical element for its implementation is the availability of high-fidelity initial states, such as |0〉 and the 'magic state'. Here, we report an experiment, performed in a nuclear magnetic resonance (NMR) quantum processor, showing sufficient quantum control to improve the fidelity of imperfect initial magic states by distilling five of them into one with higher fidelity.

High-precision Al-Mg isotopic systematics in USNM 3898 - The benchmark "ALL" for initial 87Sr/86Sr in the earliest Solar System

NASA Astrophysics Data System (ADS)

MacPherson, G. J.; Defouilloy, C.; Kita, N. T.

2018-06-01

The Allende CAI USNM 3898 is the basis for "ALL", the lowest measured initial 87Sr/86Sr value in any solar system material including other CAIs (Gray et al., 1973). If the value ALL is correct (debated), then USNM 3898 must be 1-2 million years older than other CAIs (Podosek et al., 1991). This would require in turn that it have a much higher initial 26Al/27Al value than other CAIs, on the order of 4 × 10-4. Podosek et al. (1991) showed that this is not the case, with initial 26Al/27Al = (4.5 ± 0.7) × 10-5, but their Mg-isotopic data had large error bars and there was clear isotopic disturbance in the data having the highest 27Al/24Mg. Without the latter data, the slope of their isochron is higher (5.10 ± 1.19) × 10-5) and within (large) error of being supracanonical. We used high-precision SIMS to re-determine the initial 26Al/27Al in this CAI and obtained a value of (5.013 ± 0.099) × 10-5, with an intercept δ26Mg* = - 0.008 ± 0.048 and MSWD = 1.3. This value is indistinguishable from that measured in many other CAIs and conclusively shows that USNM 3898 is not uniquely ancient. We also confirmed evidence of later isotopic disturbance, similar to what Podosek et al. found, indicating a re-melting and evaporation event some 200,000 years after initial CAI solidification.

Four-year follow-up of pregnancy-associated osteoporosis: a case report.

PubMed

Takahashi, Naoto; Arai, Itaru; Kayama, Satoru; Ichiji, Kenji; Fukuda, Hironari; Handa, Jun-Ichi; Konno, Shin-Ichi

2014-01-01

A 22-year-old woman presented with complaints of severe pain in a wide region of the thoracolumbar spine. She developed severe pain in the thoracolumbar spine region 2 months after her first delivery and was referred 1 month later. A lateral thoracic X-ray showed depressed degenerative vertebrae (T7, T9). One month after the initial examination, thoracic sagittal magnetic resonance imaging showed low intensity areas on T1-weighted imaging and iso-high intensity areas on T2-weighted imaging at T5, 7, 8, 9 and 11. Bone mineral density measured by ultrasound was low (%YAM 76%). The bone metabolic markers were high, suggesting accelerated osteoclast activity. These findings prompted a diagnosis of pregnancy-associated osteoporosis. She was asked to stop breastfeeding and to wear a lumbar brace, and treatment with nutritional calcium, activated vitamin D3, and risedronate sodium was started. Her low back pain almost disappeared after treatment. Bone metabolic markers showed normalization 8 months after the initial examination. Risedronate sodium was stopped 2 years and 2 months after the initial examination. Teriparatide treatment was started because her bone mineral density remained low; however, the osteoblast marker P1NP was not increased 5 months after the start of teriparatide treatment.

Improving Numerical Weather Predictions of Summertime Precipitation Over the Southeastern U.S. Through a High-Resolution Initialization of the Surface State

NASA Technical Reports Server (NTRS)

Case, Jonathan L.; Kumar, Sujay V.; Krikishen, Jayanthi; Jedlovec, Gary J.

2011-01-01

It is hypothesized that high-resolution, accurate representations of surface properties such as soil moisture and sea surface temperature are necessary to improve simulations of summertime pulse-type convective precipitation in high resolution models. This paper presents model verification results of a case study period from June-August 2008 over the Southeastern U.S. using the Weather Research and Forecasting numerical weather prediction model. Experimental simulations initialized with high-resolution land surface fields from the NASA Land Information System (LIS) and sea surface temperature (SST) derived from the Moderate Resolution Imaging Spectroradiometer (MODIS) are compared to a set of control simulations initialized with interpolated fields from the National Centers for Environmental Prediction 12-km North American Mesoscale model. The LIS land surface and MODIS SSTs provide a more detailed surface initialization at a resolution comparable to the 4-km model grid spacing. Soil moisture from the LIS spin-up run is shown to respond better to the extreme rainfall of Tropical Storm Fay in August 2008 over the Florida peninsula. The LIS has slightly lower errors and higher anomaly correlations in the top soil layer, but exhibits a stronger dry bias in the root zone. The model sensitivity to the alternative surface initial conditions is examined for a sample case, showing that the LIS/MODIS data substantially impact surface and boundary layer properties.

Dynamic Fracture Initiation Toughness at Elevated Temperatures With Application to the New Generation of Titanium Aluminide Alloys. Chapter 8

NASA Technical Reports Server (NTRS)

Shazly, Mostafa; Prakash, Vikas; Draper, Susan; Shukla, Arun (Editor)

2006-01-01

Recently, a new generation of titanium aluminide alloy, named Gamma-Met PX, has been developed with better rolling and post-rolling characteristics. I'revious work on this alloy has shown the material to have higher strengths at room and elevated temperatures when compared with other gamma titanium aluminides. In particular, this new alloy has shown increased ductility at elevated temperatures under both quasi-static and high strain rate uniaxial compressive loading. However, its high strain rate tensile ductility at room and elevated temperatures is limited to approx. 1%. In the present chapter, results of a study to investigate the effects of loading rate and test temperature on the dynamic fracture initiation toughness in Gamma-Met PX are presented. Modified split Hopkinson pressure bar was used along with high-speed photography to determine the crack initiation time. Three-point bend dynamic fracture experiments were conducted at impact speeds of approx. 1 m/s and tests temperatures of up-to 1200 C. The results show that thc dynamic fracture initiation toughness decreases with increasing test temperatures beyond 600 C. Furthermore, thc effect of long time high temperature air exposure on the fracture toughness was investigated. The dynamic fracture initiation toughness was found to decrease with increasing exposure time. The reasons behind this drop are analyzed and discussed.

Influence of Algae Age and Population on the Response to TiO₂ Nanoparticles.

PubMed

Metzler, David M; Erdem, Ayca; Huang, Chin Pao

2018-03-25

This work shows the influence of algae age (at the time of the exposure) and the initial algae population on the response of green algae Raphidocelis subcapitata to titanium dioxide nanoparticles (TiO₂ NPs). The different algae age was obtained by changes in flow rate of continually stirred tank reactors prior to NP exposure. Increased algae age led to a decreased growth, variations in chlorophyll content, and an increased lipid peroxidation. Increased initial algae population (0.3-4.2 × 10⁶ cells/mL) at a constant NP concentration (100 mg/L) caused a decline in the growth of algae. With increased initial algae population, the lipid peroxidation and chlorophyll both initially decreased and then increased. Lipid peroxidation had 4× the amount of the control at high and low initial population but, at mid-ranged initial population, had approximately half the control value. Chlorophyll a results also showed a similar trend. These results indicate that the physiological state of the algae is important for the toxicological effect of TiO₂ NPs. The condition of algae and exposure regime must be considered in detail when assessing the toxicological response of NPs to algae.

Influence of Algae Age and Population on the Response to TiO2 Nanoparticles

PubMed Central

Metzler, David M.; Erdem, Ayca; Huang, Chin Pao

2018-01-01

This work shows the influence of algae age (at the time of the exposure) and the initial algae population on the response of green algae Raphidocelis subcapitata to titanium dioxide nanoparticles (TiO2 NPs). The different algae age was obtained by changes in flow rate of continually stirred tank reactors prior to NP exposure. Increased algae age led to a decreased growth, variations in chlorophyll content, and an increased lipid peroxidation. Increased initial algae population (0.3−4.2 × 106 cells/mL) at a constant NP concentration (100 mg/L) caused a decline in the growth of algae. With increased initial algae population, the lipid peroxidation and chlorophyll both initially decreased and then increased. Lipid peroxidation had 4× the amount of the control at high and low initial population but, at mid-ranged initial population, had approximately half the control value. Chlorophyll a results also showed a similar trend. These results indicate that the physiological state of the algae is important for the toxicological effect of TiO2 NPs. The condition of algae and exposure regime must be considered in detail when assessing the toxicological response of NPs to algae. PMID:29587381

Initial conditions for cosmological N-body simulations of the scalar sector of theories of Newtonian, Relativistic and Modified Gravity

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

Valkenburg, Wessel; Hu, Bin, E-mail: valkenburg@lorentz.leidenuniv.nl, E-mail: hu@lorentz.leidenuniv.nl

2015-09-01

We present a description for setting initial particle displacements and field values for simulations of arbitrary metric theories of gravity, for perfect and imperfect fluids with arbitrary characteristics. We extend the Zel'dovich Approximation to nontrivial theories of gravity, and show how scale dependence implies curved particle paths, even in the entirely linear regime of perturbations. For a viable choice of Effective Field Theory of Modified Gravity, initial conditions set at high redshifts are affected at the level of up to 5% at Mpc scales, which exemplifies the importance of going beyond Λ-Cold Dark Matter initial conditions for modifications of gravitymore » outside of the quasi-static approximation. In addition, we show initial conditions for a simulation where a scalar modification of gravity is modelled in a Lagrangian particle-like description. Our description paves the way for simulations and mock galaxy catalogs under theories of gravity beyond the standard model, crucial for progress towards precision tests of gravity and cosmology.« less

Suppression, accessibility of death-related thoughts, and cultural worldview defense: exploring the psychodynamics of terror management.

PubMed

Arndt, J; Greenberg, J; Solomon, S; Pyszczynski, T; Simon, L

1997-07-01

Previous research has shown that after a mortality-salience (MS) treatment, death thought accessibility and worldview defense are initially low and then increase after a delay, suggesting that a person's initial response to conscious thoughts of mortality is to actively suppress death thoughts. If so, then high cognitive load, by disrupting suppression efforts, should lead to immediate increases in death thought accessibility and cultural worldview defense. Studies 1 and 2 supported this reasoning. Specifically, Study 1 replicated the delayed increase in death accessibility after MS among low cognitive load participants but showed a reversed pattern among participants under high cognitive load. Study 2 showed that, unlike low cognitive load participants, high cognitive load participants exhibited immediate increase in pro-American bias after MS. Study 3 demonstrated that worldview defense in response to MS reduces the delayed increase in death accessibility. Implications of these findings for understanding both terror management processes and psychological defense in general are discussed.

Exploring the effect of Al2O3 ALD coating on a high gradient ILC single-cell cavity

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

Grigory Eremeev, Anne-Marie Valente, Andy Wu, Diefeng Gu

2012-07-01

Encouraged by work at Argonne National Lab, we investigated atomic layer deposition technique (ALD) for high gradient superconducting RF cavities at JLab with an ALD coating system of Old Dominion University located on the JLab site. The goal of this study was to look into the possibility of coating a dielectric layer on top of RF niobium surface at a lower temperature of 120 C as compared to ANL coatings at 200 C to preserve niobium pentoxide on niobium surface. The initial coatings showed complete, but non-uniform coatings of the surface with several areas exhibiting discoloration, which was probably duemore » to the temperature variation across the cavity surface. The initial coating showed a high RF losses, which were improved after discolored areas on the beam tubes were removed with HF rinse of the beam tubes only. The best result was 2 109 low field Q0 and Eacc = 18 MV/m limited by available power.« less

Nanoscaled Na3PS4 Solid Electrolyte for All-Solid-State FeS2/Na Batteries with Ultrahigh Initial Coulombic Efficiency of 95% and Excellent Cyclic Performances.

PubMed

Wan, Hongli; Mwizerwa, Jean Pierre; Qi, Xingguo; Xu, Xiaoxiong; Li, Hong; Zhang, Qiang; Cai, Liangting; Hu, Yong-Sheng; Yao, Xiayin

2018-04-18

Nanosized Na 3 PS 4 solid electrolyte with an ionic conductivity of 8.44 × 10 -5 S cm -1 at room temperature is synthesized by a liquid-phase reaction. The resultant all-solid-state FeS 2 /Na 3 PS 4 /Na batteries show an extraordinary high initial Coulombic efficiency of 95% and demonstrate high energy density of 611 Wh kg -1 at current density of 20 mA g -1 at room temperature. The outstanding performances of the battery can be ascribed to good interface compatibility and intimate solid-solid contact at FeS 2 electrode/nanosized Na 3 PS 4 solid electrolytes interface. Meanwhile, excellent cycling stability is achieved for the battery after cycling at 60 mA g -1 for 100 cycles, showing a high capacity of 287 mAh g -1 with the capacity retention of 80%.

Extremely high-rate, uniform dissolution of alloy C-22 in anhydrous organic solutions at room temperature

DOE PAGES

Schindelholz, Eric J.; Christie, Michael A.; Allwein, Shawn P.; ...

2016-06-21

During routine pharmaceutical development and scale-up work, severe corrosion of a Hastelloy Alloy C-22 filter dryer was observed after single, short (several hours) contact with the product slurry at room temperature. Initial investigations showed that the presence of both 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) and HCl was sufficient in an acetonitrile solution to cause rapid corrosion of C-22. More detailed mass loss studies showed initial corrosion rates exceeding25 mm/year that then decreased over several hours to steady state rates of 3-5 mm/year. The corrosion was highly uniform. Electrochemical measurements demonstrated that although C-22 is spontaneously passive in acetonitrile solution, the presence of HClmore » leads to the development of a transpassive region. Furthermore, DDQ is a sufficiently strong oxidizer, particularly in acidic solutions, to polarize the C-22 well into the transpassive region, leading to the observed high corrosion rates.« less

Microwave-induced electrostatic etching: generation of highly reactive magnesium for application in Grignard reagent formation.

PubMed

van de Kruijs, Bastiaan H P; Dressen, Mark H C L; Meuldijk, Jan; Vekemans, Jef A J M; Hulshof, Lumbertus A

2010-04-07

A detailed study regarding the influence of microwave irradiation on the formation of a series of Grignard reagents in terms of rates and selectivities has revealed that these heterogeneous reactions may display a beneficial microwave effect. The interaction between microwaves and magnesium turnings generates violent electrostatic discharges. These discharges on magnesium lead to melting of the magnesium surface, thus generating highly active magnesium particles. As compared to conventional operation the microwave-induced discharges on the magnesium surface lead to considerably shorter initiation times for the insertion of magnesium in selected substrates (i.e. halothiophenes, halopyridines, octyl halides, and halobenzenes). Thermographic imaging and surface characterization by scanning electron microscopy showed that neither selective heating nor a "specific" microwave effect was causing the reduction in initiation times. This novel and straightforward initiation method eliminates the use of toxic and environmentally adverse initiators. Thus, this initiation method limits the formation of by-products. We clearly demonstrated that microwave irradiation enables fast Grignard reagent formation. Therefore, microwave technology is promising for process intensification of Grignard based coupling reactions.

A high-accuracy two-position alignment inertial navigation system for lunar rovers aided by a star sensor with a calibration and positioning function

NASA Astrophysics Data System (ADS)

Lu, Jiazhen; Lei, Chaohua; Yang, Yanqiang; Liu, Ming

2016-12-01

An integrated inertial/celestial navigation system (INS/CNS) has wide applicability in lunar rovers as it provides accurate and autonomous navigational information. Initialization is particularly vital for a INS. This paper proposes a two-position initialization method based on a standard Kalman filter. The difference between the computed star vector and the measured star vector is measured. With the aid of a star sensor and the two positions, the attitudinal and positional errors can be greatly reduced, and the biases of three gyros and accelerometers can also be estimated. The semi-physical simulation results show that the positional and attitudinal errors converge within 0.07″ and 0.1 m, respectively, when the given initial positional error is 1 km and the attitudinal error is 10°. These good results show that the proposed method can accomplish alignment, positioning and calibration functions simultaneously. Thus the proposed two-position initialization method has the potential for application in lunar rover navigation.

Brief report: High and low level initiations of joint attention, and response to joint attention: differential relationships with language and imitation.

PubMed

Pickard, Katherine E; Ingersoll, Brooke R

2015-01-01

Frequency of high-level (showing/pointing) and low-level (coordinated gaze shifts) behaviors on the Early Social Communication Scales are often used as a measure of joint attention initiations (IJA). This study examined the degree to which these skills and response to joint attention (RJA; e.g. gaze following) were differentially related to measures of language and imitation in 53 children with autism spectrum disorder between the ages of 22 and 93 months. High-level and low-level IJA were not associated with each other, and only high-level IJA was associated with RJA, and language and imitation measures. High-level IJA and RJA were unique predictors of imitation, while RJA was a unique predictor of language. Findings indicate that IJA involves distinct skills, with high-level behaviors more closely related to social-communication skills.

Outcome of patients with reactive amyloidosis associated with rheumatoid arthritis in dialysis treatment.

PubMed

Kuroda, Takeshi; Tanabe, Naohito; Sato, Hiroe; Ajiro, Jyunya; Wada, Yoko; Murakami, Syuichi; Hasegawa, Hisashi; Sakatsume, Minoru; Nakano, Masaaki; Gejyo, Fumitake

2006-10-01

The aim was to analyze the clinical outcome of a group of 51 patients diagnosed with systemic amyloidosis associated with rheumatoid arthritis who received hemodialysis (HD) as renal replacement therapy. We monitored the clinical course of the disease and factors that could influence survival. Determination of the onset of the underlying disorder was made retrospectively by reviewing the patient's chart when a diagnosis of amyloid was confirmed. During a 96.9 person-year follow-up, 42 patients died. Survival of these 51 patients from the initiation of HD at 251 days was 50%. Poor prognosis in amyloid patients was mainly due to a large number of sudden deaths immediately following HD therapy. Out of 51 patients 21 needed unplanned initiation of HD. The unplanned initiation was significantly associated with poor survival. Seventy-five percentile of creatinine clearance (Ccr) was 9.7 ml/min, and 75% of these patients who initiated HD had highly impaired renal functional states. These data indicated that amyloidotic patients with HD showed a high mortality rate; therefore, planned initiation of HD was highly recommended to improve the patient's survival. Particular attention was given to the Ccr levels, because the levels of serum creatinine may not be a useful marker for some patients with amyloidosis.

Medicare Beneficiary Satisfaction with Durable Medical Equipment Suppliers

PubMed Central

Hoerger, Thomas J.; Finkelstein, Eric A.; Bernard, Shulamit L.

2001-01-01

CMS has recently launched a series of initiatives to control Medicare spending on durable medical equipment (DME) and prosthetics, orthotics, and supplies (DMEPOS). An important question is how these initiatives will affect beneficiary satisfaction. Using survey data, we analyze Medicare beneficiary satisfaction with DMEPOS suppliers in two Florida counties. Our results show that beneficiaries are currently highly satisfied with their DMEPOS suppliers. Beneficiary satisfaction is positively related to rapid delivery, training, dependability, and frequency of service. Results of our analysis can be used as baseline estimates in evaluating CMS initiatives to reduce Medicare payments for DMEPOS. PMID:12500367

Logistic regression trees for initial selection of interesting loci in case-control studies

PubMed Central

Nickolov, Radoslav Z; Milanov, Valentin B

2007-01-01

Modern genetic epidemiology faces the challenge of dealing with hundreds of thousands of genetic markers. The selection of a small initial subset of interesting markers for further investigation can greatly facilitate genetic studies. In this contribution we suggest the use of a logistic regression tree algorithm known as logistic tree with unbiased selection. Using the simulated data provided for Genetic Analysis Workshop 15, we show how this algorithm, with incorporation of multifactor dimensionality reduction method, can reduce an initial large pool of markers to a small set that includes the interesting markers with high probability. PMID:18466557

Active Nodal Task Seeking for High-Performance, Ultra-Dependable Computing

DTIC Science & Technology

1994-07-01

implementation. Figure 1 shows a hardware organization of ANTS: stand-alone computing nodes inter - connected by buses. 2.1 Run Time Partitioning The...nodes in 14 respond to changing loads [27] or system reconfiguration [26]. Existing techniques are all source-initiated or server-initiated [27]. 5.1...short-running task segments. The task segments must be short-running in order that processors will become avalable often enough to satisfy changing

Effect of initial moisture content on the in-vessel composting under air pressure of organic fraction of municipal solid waste in Morocco

PubMed Central

2013-01-01

This study aimed to evaluate the effect of initial moisture content on the in-vessel composting under air pressure of organic fraction of municipal solid waste in Morocco in terms of internal temperature, produced gases quantity, organic matter conversion rate, and the quality of the final composts. For this purpose, in-vessel bioreactor was designed and used to evaluate both appropriate initial air pressure and appropriate initial moisture content for the composting process. Moreover, 5 experiments were carried out within initial moisture content of 55%, 65%, 70%, 75% and 85%. The initial air pressure and the initial moisture content of the mixture showed a significant effect on the aerobic composting. The experimental results demonstrated that for composting organic waste, relatively high moisture contents are better at achieving higher temperatures and retaining them for longer times. This study suggested that an initial moisture content of around 75%, under 0.6 bar, can be considered as being suitable for efficient composting of organic fraction of municipal solid waste. These last conditions, allowed maximum value of temperature and final composting product with good physicochemical properties as well as higher organic matter degradation and higher gas production. Moreover, final compost obtained showed good maturity levels and can be used for agricultural applications. PMID:23369502

Macroscopic phase separation in high-temperature superconductors

PubMed Central

Wen, Hai-Hu

2000-01-01

High-temperature superconductivity is recovered by introducing extra holes to the Cu-O planes, which initially are insulating with antiferromagnetism. In this paper I present data to show the macroscopic electronic phase separation that is caused by either mobile doping or electronic instability in the overdoped region. My results clearly demonstrate that the electronic inhomogeneity is probably a general feature of high-temperature superconductors. PMID:11027323

Numerical simulation on the powder propellant pickup characteristics of feeding system at high pressure

NASA Astrophysics Data System (ADS)

Sun, Haijun; Hu, Chunbo; Zhu, Xiaofei

2017-10-01

A numerical study of powder propellant pickup progress at high pressure was presented in this paper by using two-fluid model with kinetic theory of granular flow in the computational fluid dynamics software package ANSYS/Fluent. Simulations were conducted to evaluate the effects of initial pressure, initial powder packing rate and mean particle diameter on the flow characteristics in terms of velocity vector distribution, granular temperature, pressure drop, particle velocity and volume. The numerical results of pressure drop were also compared with experiments to verify the TFM model. The simulated results show that the pressure drop value increases as the initial pressure increases, and the granular temperature under the conditions of different initial pressures and packing rates is almost the same in the area of throttling orifice plate. While there is an appropriate value for particle size and packing rate to form a ;core-annulus; structure in powder box, and the time-averaged velocity vector distribution of solid phase is inordinate.

Reducing Non-Attendance Rates for Assessment at an Eating Disorders Service: A Quality Improvement Initiative.

PubMed

Jenkins, Paul E

2017-10-01

Rates of non-attendance at initial appointments within community eating disorder (ED) services are frequently high, although this has received relatively little research attention and no reports of interventions designed to address this. The current report describes outcomes following a change of procedure introducing a 'partial booking' system. Attendance rates at first appointments (N = 1260) were audited following introduction of a system designed to reduce non-attendance in January 2013 within a UK ED service. Rates were compared following implementation of the new system, using a historical control group for comparison, and showed a decline from 20.4 to 15.1%, a medium-sized effect. Use of a system asking patients to book an appointment reduced non-attendance at initial appointments and may be of use to similar services experiencing high non-attendance rates. Opt-in initiatives can reduce burden resulting from long waiting times and can be easily adapted to individual services.

[Research on characteristic of interrelationship between toxic organic compound BPA and Chlorella vulgaris].

PubMed

Chen, Shan-Jia; Chen, Xiu-Rong; Yan, Long; Zhao, Jian-Guo; Zhang, Fei; Jiang, Zi-Jian

2014-04-01

The effects of different concentrations of bisphenol A (BPA) on Chlorella vulgaris and removal capacity of BPA by Chlorella vulgaris were investigated. Results showed that a low concentration (0-20 mg x L(-1)) of BPA promoted the growth of Chlorella vulgaris, whereas a relative high concentration (20-50 mg x L(-1)) of BPA inhibited the growth of Chlorella vulgaris, and the inhibition effect was positively correlated with the concentration of BPA. Likewise, a high dose of initial BPA (> 20 mg x L(-1)) led to a decline in the content of chlorephyll a. Chlorella vulgaris had BPA removal capacity when initial BPA concentration ranged from 2 mg x L(-1) to 50 mg x L(-1). There was positive correlation between the removal rate of BPA per cell and initial BPA concentration. The removal rate of BPA was the highest when initial BPA was 50 mg x L(-1), which appeared between lag phase and logarithmic phase.

Giardia Colonizes and Encysts in High-Density Foci in the Murine Small Intestine

PubMed Central

Barash, N. R.; Nosala, C.; Pham, J. K.; McInally, S. G.; Gourguechon, S.; McCarthy-Sinclair, B.

2017-01-01

ABSTRACT Giardia lamblia is a highly prevalent yet understudied protistan parasite causing significant diarrheal disease worldwide. Hosts ingest Giardia cysts from contaminated sources. In the gastrointestinal tract, cysts excyst to become motile trophozoites, colonizing and attaching to the gut epithelium. Trophozoites later differentiate into infectious cysts that are excreted and contaminate the environment. Due to the limited accessibility of the gut, the temporospatial dynamics of giardiasis in the host are largely inferred from laboratory culture and thus may not mirror Giardia physiology in the host. Here, we have developed bioluminescent imaging (BLI) to directly interrogate and quantify the in vivo temporospatial dynamics of Giardia infection, thereby providing an improved murine model to evaluate anti-Giardia drugs. Using BLI, we determined that parasites primarily colonize the proximal small intestine nonuniformly in high-density foci. By imaging encystation-specific bioreporters, we show that encystation initiates shortly after inoculation and continues throughout the duration of infection. Encystation also initiates in high-density foci in the proximal small intestine, and high density contributes to the initiation of encystation in laboratory culture. We suggest that these high-density in vivo foci of colonizing and encysting Giardia likely result in localized disruption to the epithelium. This more accurate visualization of giardiasis redefines the dynamics of the in vivo Giardia life cycle, paving the way for future mechanistic studies of density-dependent parasitic processes in the host. IMPORTANCE Giardia is a single-celled parasite causing significant diarrheal disease in several hundred million people worldwide. Due to limited access to the site of infection in the gastrointestinal tract, our understanding of the dynamics of Giardia infections in the host has remained limited and largely inferred from laboratory culture. To better understand Giardia physiology and colonization in the host, we developed imaging methods to quantify Giardia expressing bioluminescent physiological reporters in two relevant animal models. We discovered that parasites primarily colonize and encyst in the proximal small intestine in discrete, high-density foci. We also show that high parasite density contributes to encystation initiation. PMID:28656177

Patient Characteristics and Comorbidities Influence Walking Distances in Symptomatic Peripheral Arterial Disease: A Large One-Year Physiotherapy Cohort Study.

PubMed

Dörenkamp, Sarah; Mesters, Ilse; de Bie, Rob; Teijink, Joep; van Breukelen, Gerard

2016-01-01

The aim of this study is to investigate the association between age, gender, body-mass index, smoking behavior, orthopedic comorbidity, neurologic comorbidity, cardiac comorbidity, vascular comorbidity, pulmonic comorbidity, internal comorbidity and Initial Claudication Distance during and after Supervised Exercise Therapy at 1, 3, 6 and 12 months in a large sample of patients with Intermittent Claudication. Data was prospectively collected in standard physiotherapy care. Patients received Supervised Exercise Therapy according to the guideline Intermittent Claudication of the Royal Dutch Society for Physiotherapy. Three-level mixed linear regression analysis was carried out to analyze the association between patient characteristics, comorbidities and Initial Claudication Distance at 1, 3, 6 and 12 months. Data from 2995 patients was analyzed. Results showed that being female, advanced age and a high body-mass index were associated with lower Initial Claudication Distance at all-time points (p = 0.000). Besides, a negative association between cardiac comorbidity and Initial Claudication Distance was revealed (p = 0.011). The interaction time by age, time by body-mass index and time by vascular comorbidity were significantly associated with Initial Claudication Distance (p≤ 0.05). Per year increase in age (range: 33-93 years), the reduction in Initial Claudication Distance was 8m after 12 months of Supervised Exercise Therapy. One unit increase in body-mass index (range: 16-44 kg/m2) led to 10 m less improvement in Initial Claudication Distance after 12 months and for vascular comorbidity the reduction in improvement was 85 m after 12 months. This study reveals that females, patients at advanced age, patients with a high body-mass index and cardiac comorbidity are more likely to show less improvement in Initial Claudication Distances (ICD) after 1, 3, 6 and 12 months of Supervised Exercise Therapy. Further research should elucidate treatment adaptations that optimize treatment outcomes for these subgroups.

Binary neutron star merger simulations with different initial orbital frequency and equation of state

NASA Astrophysics Data System (ADS)

Maione, F.; De Pietri, R.; Feo, A.; Löffler, F.

2016-09-01

We present results from three-dimensional general relativistic simulations of binary neutron star coalescences and mergers using public codes. We considered equal mass models where the baryon mass of the two neutron stars is 1.4{M}⊙ , described by four different equations of state (EOS) for the cold nuclear matter (APR4, SLy, H4, and MS1; all parametrized as piecewise polytropes). We started the simulations from four different initial interbinary distances (40,44.3,50, and 60 km), including up to the last 16 orbits before merger. That allows us to show the effects on the gravitational wave (GW) phase evolution, radiated energy and angular momentum due to: the use of different EOS, the orbital eccentricity present in the initial data and the initial separation (in the simulation) between the two stars. Our results show that eccentricity has a major role in the discrepancy between numerical and analytical waveforms until the very last few orbits, where ‘tidal’ effects and missing high-order post-Newtonian coefficients also play a significant role. We test different methods for extrapolating the GW signal extracted at finite radii to null infinity. We show that an effective procedure for integrating the Newman-Penrose {\\psi }4 signal to obtain the GW strain h is to apply a simple high-pass digital filter to h after a time domain integration, where only the two physical motivated integration constants are introduced. That should be preferred to the more common procedures of introducing additional integration constants, integrating in the frequency domain or filtering {\\psi }4 before integration.

Latitudinal Expansion of the Holocene Optimum in the East Asian Monsoon Region

NASA Astrophysics Data System (ADS)

Zhou, X.; Sun, L.; Zhan, T.; Huang, W.; Zhou, X.; Hao, Q.; He, X.; Zhao, C.; Zhang, J.; Qiao, Y.; Ge, J.; Yan, P.; Shao, D.; Chu, Z.; Yang, W.

2014-12-01

With increasingly abundant high resolution and high precision records of East Asian monsoon, its spatial and temporal dynamics during the Holocene have been extensively studied. However, partly due to the lack of records in high latitude areas and the age uncertainties, these studies characterized a wide range of spatial-temporal patterns of Holocene Optimum (HO). We reconstructed a 14,000-year record of vegetation using sediments from a crater lake in Northeast China. Analyses of the vegetation time series show that HO began around 6,000 a BP in Northeast China, significantly later than generally recognized. By comparison with Holocene records of vegetation in other regions of the East Asia, we found a marked northward shift of initial time of HO from 10,600 a BP in South China to 6,000 a BP in Northeast China, which appeared to be forced by the shrinkage of the northern hemisphere ice-sheet (NHIS) during early to mid Holocene. Finally, we fitted a regression model of initial HO time on latitude, which allows us to make prediction of initial HO time based on their geographical locations. This study reveals a strong relationship between latitude and initial HO times and provides a window towards understanding the joint forcing of high and low latitude factors on regional climate.

AN EVOLVING STELLAR INITIAL MASS FUNCTION AND THE GAMMA-RAY BURST REDSHIFT DISTRIBUTION

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

Wang, F. Y.; Dai, Z. G.

2011-02-01

Recent studies suggest that Swift gamma-ray bursts (GRBs) may not trace an ordinary star formation history (SFH). Here, we show that the GRB rate turns out to be consistent with the SFH with an evolving stellar initial mass function (IMF). We first show that the latest Swift sample of GRBs reveals an increasing evolution in the GRB rate relative to the ordinary star formation rate at high redshifts. We then assume only massive stars with masses greater than the critical value to produce GRBs and use an evolving stellar IMF suggested by Dave to fit the latest GRB redshift distribution.more » This evolving IMF would increase the relative number of massive stars, which could lead to more GRB explosions at high redshifts. We find that the evolving IMF can well reproduce the observed redshift distribution of Swift GRBs.« less

Power, propensity to negotiate, and moving first in competitive interactions.

PubMed

Magee, Joe C; Galinsky, Adam D; Gruenfeld, Deborah H

2007-02-01

Five experiments investigated how the possession and experience of power affects the initiation of competitive interaction. In Experiments 1a and 1b, high-power individuals displayed a greater propensity to initiate a negotiation than did low-power individuals. Three additional experiments showed that power increased the likelihood of making the first move in a variety of competitive interactions. In Experiment 2, participants who were semantically primed with power were nearly 4 times as likely as participants in a control condition to choose to make the opening arguments in a debate competition scenario. In Experiment 3, negotiators with strong alternatives to a negotiation were more than 3 times as likely to spontaneously express an intention to make the first offer compared to participants who lacked any alternatives. Experiment 4 showed that high-power negotiators were more likely than low-power negotiators to actually make the first offer and that making the first offer produced a bargaining advantage.

Startup analysis for a high temperature gas loaded heat pipe

NASA Technical Reports Server (NTRS)

Sockol, P. M.

1973-01-01

A model for the rapid startup of a high-temperature gas-loaded heat pipe is presented. A two-dimensional diffusion analysis is used to determine the rate of energy transport by the vapor between the hot and cold zones of the pipe. The vapor transport rate is then incorporated in a simple thermal model of the startup of a radiation-cooled heat pipe. Numerical results for an argon-lithium system show that radial diffusion to the cold wall can produce large vapor flow rates during a rapid startup. The results also show that startup is not initiated until the vapor pressure p sub v in the hot zone reaches a precise value proportional to the initial gas pressure p sub i. Through proper choice of p sub i, startup can be delayed until p sub v is large enough to support a heat-transfer rate sufficient to overcome a thermal load on the heat pipe.

Flux-tunable heat sink for quantum electric circuits.

PubMed

Partanen, M; Tan, K Y; Masuda, S; Govenius, J; Lake, R E; Jenei, M; Grönberg, L; Hassel, J; Simbierowicz, S; Vesterinen, V; Tuorila, J; Ala-Nissila, T; Möttönen, M

2018-04-20

Superconducting microwave circuits show great potential for practical quantum technological applications such as quantum information processing. However, fast and on-demand initialization of the quantum degrees of freedom in these devices remains a challenge. Here, we experimentally implement a tunable heat sink that is potentially suitable for the initialization of superconducting qubits. Our device consists of two coupled resonators. The first resonator has a high quality factor and a fixed frequency whereas the second resonator is designed to have a low quality factor and a tunable resonance frequency. We engineer the low quality factor using an on-chip resistor and the frequency tunability using a superconducting quantum interference device. When the two resonators are in resonance, the photons in the high-quality resonator can be efficiently dissipated. We show that the corresponding loaded quality factor can be tuned from above 10 5 down to a few thousand at 10 GHz in good quantitative agreement with our theoretical model.

Surfactant studies for bench-scale operation

NASA Technical Reports Server (NTRS)

Hickey, Gregory S.; Sharma, Pramod K.

1992-01-01

A phase 2 study was initiated to investigate surfactant-assisted coal liquefaction, with the objective of quantifying the enhancement in liquid yields and product quality. This publication covers the first quarter of work. The major accomplishments were: the refurbishment of the high-pressure, high-temperature reactor autoclave, the completion of four coal liquefaction runs with Pittsburgh #8 coal, two each with and without sodium lignosulfonate surfactant, and the development of an analysis scheme for the product liquid filtrate and filter cake. Initial results at low reactor temperatures show that the addition of the surfactant produces an improvement in conversion yields and an increase in lighter boiling point fractions for the filtrate.

A comparison of GLAS SAT and NMC high resolution NOSAT forecasts from 19 and 11 February 1976

NASA Technical Reports Server (NTRS)

Atlas, R.

1979-01-01

A subjective comparison of the Goddard Laboratory for Atmospheric Sciences (GLAS) and the National Meteorological Center (NMC) high resolution model forecasts is presented. Two cases where NMC's operational model in 1976 had serious difficulties in forecasting for the United States were examined. For each of the cases, the GLAS model forecasts from initial conditions which included satellite sounding data were compared directly to the NMC higher resolution model forecasts, from initial conditions which excluded the satellite data. The comparison showed that the GLAS satellite forecasts significantly improved upon the current NMC operational model's predictions in both cases.

Removal of high concentration p-nitrophenol in aqueous solution by zero valent iron with ultrasonic irradiation (US-ZVI).

PubMed

Lai, Bo; Chen, Zhaoyu; Zhou, Yuexi; Yang, Ping; Wang, Juling; Chen, Zhiqiang

2013-04-15

In this study, the US-ZVI system was used to produce the strong reductants including H and nascent Fe(2+) ions to eliminate the toxicity of the high concentration p-nitrophenol (PNP) wastewater. The effect of the reactor structure, initial pH, ZVI dosage, ultrasonic power and initial PNP concentration on the removal efficiency of PNP from water was investigated intensively. The results show that a higher removal rate can be obtained by using a conical structure reactor, and the lower initial pH can aid the acceleration of PNP removal rate by using US-ZVI system. Furthermore, the removal efficiencies of PNP increased obviously with the increase of initial ZVI concentration from 0 to 15 gL(-1). Also, the treatment capacity of ZVI was enhanced remarkably by the ultrasonic irradiation, and the US-ZVI system can maintain high treatment efficiency for the high concentration PNP wastewater (500-10,000 mgL(-1)). Meanwhile, the high removal efficiency of PNP was mainly resulted from the synergistic reaction of ZVI and US. At last, the main degradation product (i.e., p-aminophenol) was detected by gas chromatography-mass spectrum (GC-MS). Thus, the reaction pathway of PNP in the US-ZVI system is proposed as a reducing process by the H and nascent Fe(2+) ions. Copyright © 2013 Elsevier B.V. All rights reserved.

ECL-IAA and ECL-GADA Can Identify High-Risk Single Autoantibody-Positive Relatives in the TrialNet Pathway to Prevention Study.

PubMed

Steck, Andrea K; Fouts, Alexandra; Miao, Dongmei; Zhao, Zhiyuan; Dong, Fran; Sosenko, Jay; Gottlieb, Peter; Rewers, Marian J; Yu, Liping

2016-07-01

Relatives with single positive islet autoantibodies have a much lower risk of progression to diabetes than those with multiple autoantibodies. TrialNet subjects positive for single autoantibody to insulin (mIAA) (n = 50) or single autoantibody to glutamic acid decarboxylase (GADA) (n = 50) were analyzed using new electrochemiluminescence (ECL) assays (ECL-IAA and ECL-GADA, respectively) at their initial visit and longitudinally over time. Affinity assays were performed on a subset of single autoantibody-positive subjects at initial and most recent visits. After a mean follow-up of 5.3 years, 20 subjects developed type 1 diabetes. Among either single GADA or single mIAA subjects, those who were positive in the ECL assay showed higher affinity at the initial visit, and affinity results stayed consistent over time. No converting events from low to high or high to low affinity were seen over time. Confirmed positivity for ECL is associated with high affinity and can help staging of risk for type 1 diabetes in single autoantibody-positive subjects.

Haloperidol Treatment with Chronically Medicated Residents: Dose Effects on Clinical Behavior and Reinforcement Contingencies.

ERIC Educational Resources Information Center

Aman, Michael G.; And Others

1989-01-01

The study of effects of haloperidol drug therapy with 20 institutionalized mentally retarded persons found clinical changes confined to a slight reduction in stereotypic behavior and an increase in gross motor activity under the high dose condition. Subjects with high initial levels of stereotypy showed the best response to the drug. (Author/DB)

Iterative reconstruction for CT perfusion with a prior-image induced hybrid nonlocal means regularization: Phantom studies

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

Li, Bin; Lyu, Qingwen; Ma, Jianhua

2016-04-15

Purpose: In computed tomography perfusion (CTP) imaging, an initial phase CT acquired with a high-dose protocol can be used to improve the image quality of later phase CT acquired with a low-dose protocol. For dynamic regions, signals in the later low-dose CT may not be completely recovered if the initial CT heavily regularizes the iterative reconstruction process. The authors propose a hybrid nonlocal means (hNLM) regularization model for iterative reconstruction of low-dose CTP to overcome the limitation of the conventional prior-image induced penalty. Methods: The hybrid penalty was constructed by combining the NLM of the initial phase high-dose CT inmore » the stationary region and later phase low-dose CT in the dynamic region. The stationary and dynamic regions were determined by the similarity between the initial high-dose scan and later low-dose scan. The similarity was defined as a Gaussian kernel-based distance between the patch-window of the same pixel in the two scans, and its measurement was then used to weigh the influence of the initial high-dose CT. For regions with high similarity (e.g., stationary region), initial high-dose CT played a dominant role for regularizing the solution. For regions with low similarity (e.g., dynamic region), the regularization relied on a low-dose scan itself. This new hNLM penalty was incorporated into the penalized weighted least-squares (PWLS) for CTP reconstruction. Digital and physical phantom studies were performed to evaluate the PWLS-hNLM algorithm. Results: Both phantom studies showed that the PWLS-hNLM algorithm is superior to the conventional prior-image induced penalty term without considering the signal changes within the dynamic region. In the dynamic region of the Catphan phantom, the reconstruction error measured by root mean square error was reduced by 42.9% in PWLS-hNLM reconstructed image. Conclusions: The PWLS-hNLM algorithm can effectively use the initial high-dose CT to reconstruct low-dose CTP in the stationary region while reducing its influence in the dynamic region.« less

Observations of narrow bipolar events reveal how lightning is initiated in thunderstorms

PubMed Central

Rison, William; Krehbiel, Paul R.; Stock, Michael G.; Edens, Harald E.; Shao, Xuan-Min; Thomas, Ronald J.; Stanley, Mark A.; Zhang, Yang

2016-01-01

A long-standing but fundamental question in lightning studies concerns how lightning is initiated inside storms, given the absence of physical conductors. The issue has revolved around the question of whether the discharges are initiated solely by conventional dielectric breakdown or involve relativistic runaway electron processes. Here we report observations of a relatively unknown type of discharge, called fast positive breakdown, that is the cause of high-power discharges known as narrow bipolar events. The breakdown is found to have a wide range of strengths and is the initiating event of numerous lightning discharges. It appears to be purely dielectric in nature and to consist of a system of positive streamers in a locally intense electric field region. It initiates negative breakdown at the starting location of the streamers, which leads to the ensuing flash. The observations show that many or possibly all lightning flashes are initiated by fast positive breakdown. PMID:26876654

Observations of narrow bipolar events reveal how lightning is initiated in thunderstorms.

PubMed

Rison, William; Krehbiel, Paul R; Stock, Michael G; Edens, Harald E; Shao, Xuan-Min; Thomas, Ronald J; Stanley, Mark A; Zhang, Yang

2016-02-15

A long-standing but fundamental question in lightning studies concerns how lightning is initiated inside storms, given the absence of physical conductors. The issue has revolved around the question of whether the discharges are initiated solely by conventional dielectric breakdown or involve relativistic runaway electron processes. Here we report observations of a relatively unknown type of discharge, called fast positive breakdown, that is the cause of high-power discharges known as narrow bipolar events. The breakdown is found to have a wide range of strengths and is the initiating event of numerous lightning discharges. It appears to be purely dielectric in nature and to consist of a system of positive streamers in a locally intense electric field region. It initiates negative breakdown at the starting location of the streamers, which leads to the ensuing flash. The observations show that many or possibly all lightning flashes are initiated by fast positive breakdown.

Hda inactivation of DnaA is the predominant mechanism preventing hyperinitiation of Escherichia coli DNA replication.

PubMed

Camara, Johanna E; Breier, Adam M; Brendler, Therese; Austin, Stuart; Cozzarelli, Nicholas R; Crooke, Elliott

2005-08-01

Initiation of DNA replication from the Escherichia coli chromosomal origin is highly regulated, assuring that replication occurs precisely once per cell cycle. Three mechanisms for regulation of replication initiation have been proposed: titration of free DnaA initiator protein by the datA locus, sequestration of newly replicated origins by SeqA protein and regulatory inactivation of DnaA (RIDA), in which active ATP-DnaA is converted to the inactive ADP-bound form. DNA microarray analyses showed that the level of initiation in rapidly growing cells that lack datA was indistinguishable from that in wild-type cells, and that the absence of SeqA protein caused only a modest increase in initiation, in agreement with flow-cytometry data. In contrast, cells lacking Hda overinitiated replication twofold, implicating RIDA as the predominant mechanism preventing extra initiation events in a cell cycle.

Early versus late initiation of epidural analgesia for labour.

PubMed

Sng, Ban Leong; Leong, Wan Ling; Zeng, Yanzhi; Siddiqui, Fahad Javaid; Assam, Pryseley N; Lim, Yvonne; Chan, Edwin S Y; Sia, Alex T

2014-10-09

Pain during childbirth is arguably the most severe pain some women may experience in their lifetime. Epidural analgesia is an effective form of pain relief during labour. Many women have concerns regarding its safety. Furthermore, epidural services and anaesthetic support may not be available consistently across all centres. Observational data suggest that early initiation of epidural may be associated with an increased risk of caesarean section, but the same findings were not seen in recent randomised controlled trials. More recent guidelines suggest that in the absence of a medical contraindication, maternal request is a sufficient medical indication for pain relief during labour. The choice of analgesic technique, agent, and dosage is based on many factors, including patient preference, medical status, and contraindications. There is no systematically reviewed evidence on the maternal and foetal outcomes and safety of this practice. This systematic review aimed to summarise the effectiveness and safety of early initiation versus late initiation of epidural analgesia in women. We considered the obstetric and fetal outcomes relevant to women and side effects of the treatments, including risk of caesarean section, instrumental birth and time to birth. We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (12 February 2014), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2014, Issue 1), MEDLINE (January 1966 to February 2014), Embase (January 1980 to February 2014) and reference lists of retrieved studies. We included all randomised controlled trials involving women undergoing epidural labour analgesia that compared early initiation versus late initiation of epidural labour analgesia. Two review authors independently assessed trials for inclusion, extracted the data and assessed the trial quality. Data were checked for accuracy. We included nine studies with a total of 15,752 women.The overall risk of bias of the studies was low, with the exception of performance bias (blinding of participants and personnel).The nine studies showed no clinically meaningful difference in risk of caesarean section with early initiation versus late initiation of epidural analgesia for labour (risk ratio (RR) 1.02; 95% confidence interval (CI) 0.96 to 1.08, nine studies, 15,499 women, high quality evidence). There was no clinically meaningful difference in risk of instrumental birth with early initiation versus late initiation of epidural analgesia for labour (RR 0.93; 95% CI 0.86 to 1.01, eight studies, 15,379 women, high quality evidence). The duration of second stage of labour showed no clinically meaningful difference between early initiation and late initiation of epidural analgesia (mean difference (MD) -3.22 minutes; 95% CI -6.71 to 0.27, eight studies, 14,982 women, high quality evidence). There was significant heterogeneity in the duration of first stage of labour and the data were not pooled.There was no clinically meaningful difference in Apgar scores less than seven at one minute (RR 0.96; 95% CI 0.84 to 1.10, seven studies, 14,924 women, high quality evidence). There was no clinically meaningful difference in Apgar scores less than seven at five minutes (RR 0.96; 95% CI 0.69 to 1.33, seven studies, 14,924 women, high quality evidence). There was no clinically meaningful difference in umbilical arterial pH between early initiation and late initiation (MD 0.01; 95% CI -0.01 to 0.03, four studies, 14,004 women, high quality evidence). There was no clinically meaningful difference in umbilical venous pH favouring early initiation (MD 0.01; 95% CI -0.00 to 0.02, four studies, 14,004 women, moderate quality evidence). There is predominantly high-quality evidence that early or late initiation of epidural analgesia for labour have similar effects on all measured outcomes. However, various forms of alternative pain relief were given to women who were allocated to delayed epidurals to cover that period of delay, so that is it hard to assess the outcomes clearly. We conclude that for first time mothers in labour who request epidurals for pain relief, it would appear that the time to initiate epidural analgesia is dependent upon women's requests.

Pork Quality Traits According to Postmortem pH and Temperature in Berkshire

PubMed Central

Kim, Tae Wan; Kim, Chul Wook; Yang, Mi Ra; No, Gun Ryoung; Kim, Il-Suk

2016-01-01

This study was performed to investigate the role of pH and temperature postmortem, and to demonstrate the importance of these factors in determining meat quality. Postmortem pH45min (pH at 45 min postmortem or initial pH) via analysis of Pearson’s correlation showed high positive correlation with pH change pHc24 (pH change from pH45min to pH24h postmortem). However, postmortem pH after 24 h (pH24h or ultimate pH) had a high negative correlation with pH change, pHc24, CIE L*, and protein content. Initial temperature postmortem (T1h ) was positively associated with a change in temperature from 45 min to 24 h postmortem (Tc24) and cooking loss, but negatively correlated with water holding capacity. Temperature at 24 h postmortem (T24h) was negatively associated with Tc24. Collectively, these results indicate that higher initial pH was associated with higher pHc24, T1h, and Tc24. However, higher initial pH was associated with a reduction in carcass weight, backfat thickness, CIE a* and b*, water holding capacity, collagen and fat content, drip loss, and cooking loss as well as decreased shear force. In contrast, CIE a* and b*, drip loss, cooking loss, and shear force in higher ultimate pH was showed by a similar pattern to higher initial pH, whereas pHc24, carcass weight, backfat thickness, water holding capacity, fat content, moisture content, protein content, T1h, T24h, and Tc24 were exhibited by completely differential patterns (p<0.05). Therefore, we suggest that initial pH, ultimate pH, and temperatures postmortem are important factors in determining the meat quality of pork. PMID:27499661

Discontinuation of Hemodialysis in a Patient with Anti-GBM Disease by the Treatment with Corticosteroids and Plasmapheresis despite Several Predictors for Dialysis-Dependence.

PubMed

Fujigaki, Yoshihide; Morimoto, Chikayuki; Iino, Risa; Taniguchi, Kei; Kawamorita, Yosuke; Asakawa, Shinichiro; Toyoki, Daigo; Miyano, Shinako; Fujii, Wataru; Ota, Tatsuru; Shibata, Shigeru; Uchida, Shunya

2017-01-01

A 26-year-old man highly suspected of having antiglomerular basement membrane (GBM) disease was treated with corticosteroid pulse therapy 9 days after initial infection-like symptoms with high procalcitonin value. The patient required hemodialysis the next day of the treatment due to oliguria. In addition to corticosteroid therapy, plasmapheresis was introduced and the patient could discontinue hemodialysis 43 days after the treatment. Kidney biopsy after initiation of hemodialysis confirmed anti-GBM disease with 86.3% crescent formation. Physician should keep in mind that active anti-GBM disease shows even high procalcitonin value in the absence of infection. To pursue recovery of renal function, the challenge of the immediate and persistent treatment with high-dose corticosteroids plus plasmapheresis for highly suspected anti-GBM disease is vitally important despite the presence of reported predictors for dialysis-dependence including oliguria and requiring hemodialysis at presentation.

Numerical models for continental break-up: Implications for the South Atlantic

NASA Astrophysics Data System (ADS)

Beniest, A.; Koptev, A.; Burov, E.

2017-03-01

We propose a mechanism that explains in one unified framework the presence of continental break-up features such as failed rift arms and high-velocity and high-density bodies that occur along the South Atlantic rifted continental margins. We used 2D and 3D numerical models to investigate the impact of thermo-rheological structure of the continental lithosphere and initial plume position on continental rifting and break-up processes. 2D experiments show that break-up can be 1) "central", mantle plume-induced and directly located above the centre of the mantle anomaly, 2) "shifted", mantle plume-induced and 50 to 200 km shifted from the initial plume location or 3) "distant", self-induced due to convection and/or slab-subduction/delamination and 300 to 800 km off-set from the original plume location. With a 3D, perfectly symmetrical and laterally homogeneous setup, the location of continental break-up can be shifted hundreds of kilometres from the initial position of the mantle anomaly. We demonstrate that in case of shifted or distant continental break-up with respect to the original plume location, multiple features can be explained. Its deep-seated source can remain below the continent at one or both sides of the newly-formed ocean. This mantle material, glued underneath the margins at lower crustal levels, resembles the geometry and location of high velocity/high density bodies observed along the South Atlantic conjugate margins. Impingement of vertically up-welled plume material on the base of the lithosphere results in pre-break-up topography variations that are located just above this initial anomaly impingement. This can be interpreted as aborted rift features that are also observed along the rifted margins. When extension continues after continental break-up, high strain rates can relocalize. This relocation has been so far attributed to rift jumps. Most importantly, this study shows that there is not one, single rift mode for plume-induced crustal break-up.

Recruitment Methods and Show Rates to a Prostate Cancer Early Detection Program for High-Risk Men: A Comprehensive Analysis

PubMed Central

Giri, Veda N.; Coups, Elliot J.; Ruth, Karen; Goplerud, Julia; Raysor, Susan; Kim, Taylor Y.; Bagden, Loretta; Mastalski, Kathleen; Zakrzewski, Debra; Leimkuhler, Suzanne; Watkins-Bruner, Deborah

2009-01-01

Purpose Men with a family history (FH) of prostate cancer (PCA) and African American (AA) men are at higher risk for PCA. Recruitment and retention of these high-risk men into early detection programs has been challenging. We report a comprehensive analysis on recruitment methods, show rates, and participant factors from the Prostate Cancer Risk Assessment Program (PRAP), which is a prospective, longitudinal PCA screening study. Materials and Methods Men 35–69 years are eligible if they have a FH of PCA, are AA, or have a BRCA1/2 mutation. Recruitment methods were analyzed with respect to participant demographics and show to the first PRAP appointment using standard statistical methods Results Out of 707 men recruited, 64.9% showed to the initial PRAP appointment. More individuals were recruited via radio than from referral or other methods (χ2 = 298.13, p < .0001). Men recruited via radio were more likely to be AA (p<0.001), less educated (p=0.003), not married or partnered (p=0.007), and have no FH of PCA (p<0.001). Men recruited via referrals had higher incomes (p=0.007). Men recruited via referral were more likely to attend their initial PRAP visit than those recruited by radio or other methods (χ2 = 27.08, p < .0001). Conclusions This comprehensive analysis finds that radio leads to higher recruitment of AA men with lower socioeconomic status. However, these are the high-risk men that have lower show rates for PCA screening. Targeted motivational measures need to be studied to improve show rates for PCA risk assessment for these high-risk men. PMID:19758657

Correlation of cancer stem cell markers and immune cell markers in resected non-small cell lung cancer.

PubMed

Huang, Zhaoqin; Yu, Haining; Zhang, Jianbo; Jing, Haiyan; Zhu, Wanqi; Li, Xiaolin; Kong, Lingling; Xing, Ligang; Yu, Jinming; Meng, Xiangjiao

2017-01-01

Background: Recent studies confirmed that immunotherapy showed prominent efficacy in non-small cell lung cancer (NSCLC). Cancer stem cells/cancer initiating cells are resistant to anticancer treatment. The purpose of the study was to analyze the correlation of cancer stem cells/cancer initiating cells and tumor-infiltrating immune cells in NSCLC. Methods: CD133, octamer 4 (OCT-4), CD8, CD56, human leukocyte antigen (HLA) class I and programmed death ligand-1 (PD-L1) were assessed in 172 resected NSCLC samples. The staining was analyzed and scored by the pathologist who was blinded to the clinical pathological data of the patients. Results: High CD8+ T cell infiltration was correlated significantly with squamous cell carcinoma histology (p=0.008). High PD-L1 expression (≥10%) was associated with high tumor status (p=0.043). Pearson's correlation test showed that CD56+ cells were negatively correlated with CD133 expression (r=-0.361, p<0.001) and weakly correlated with negative OCT-4 expression (r=-0.180, p=0.018). There was a strong positive correlation between CD8 and HLA class I (r=0.573, p<0.001). In the survival analysis, high CD8+ T cell infiltration is an independent predictor of improved disease-free survival and overall survival. Patients with low CD133 expression and high CD56 expression had a longer overall survival than those with high CD133 expression and/or low CD56 expression (p=0.013). Conclusion: There is a negative correlation between CD56+ cells and cancer stem cell markers. This correlation may confirm the possibility that natural killer cells can target CD133+ cancer stem cells/cancer initiating cells in non-small cell lung cancer.

Cardiac autonomic function during sleep: effects of alcohol dependence and evidence of partial recovery with abstinence.

PubMed

de Zambotti, Massimiliano; Willoughby, Adrian R; Baker, Fiona C; Sugarbaker, David S; Colrain, Ian M

2015-06-01

Chronic alcoholism is associated with the development of cardiac and peripheral autonomic nervous system (ANS) pathology. The aim of the present study was to evaluate the extent to which recovery in ANS function could be demonstrated over the first 4 months of abstinence. Fifteen alcoholics (7 women) were studied on three occasions: within a month of detoxification, at approximately 2 months post-detox, and at 4 months post-detox. Thirteen control subjects (6 women) were also studied on three occasions with inter-study intervals matching those of the alcoholics. Six alcoholics relapsed, 48.7 ± 27.9 days following the initial PSG session. ANS function was assessed in the first part of stable non-rapid eye movement sleep. Frequency-domain power spectral analysis of heart rate variability (HRV) produced variables including: heart rate (HR), total power (TP; an index representing total HR variability), High Frequency power (HFa; an index reflecting cardiac vagal modulation), HF proportion of total power (HFprop sympathovagal balance), and HF peak frequency (HFpf; an index reflecting respiration rate). Overall, high total and high frequency variability and low sympathovagal balance and myocardial contractility are considered as desired conditions to promote cardiovascular health. At initial assessment, alcoholics had a higher HR (p < 0.001) and respiratory rate (p < 0.01), and lower vagal activity (HFa; p < 0.01) than controls. Alcoholics showed evidence of recovery in HR (p = 0.039) and HFa (p = 0.031) with 4 months of abstinence. Alcoholics with higher TP at the initial visit showed a greater improvement in TP from the initial to the 4 month follow-up session (r = 0.75, p < 0.05). Alcoholics showed substantial recovery in HR and vagal modulation of HRV with 4 months of abstinence, with evidence that the extent of recovery in HRV may be partially determined by the extent of alcohol dependence-related insult to the cardiac ANS system. These data support other studies showing recovery in a number of ANS, central nervous system, and behavioral domains with abstinence, even in those with long-term dependence. Copyright © 2015 Elsevier Inc. All rights reserved.

Hysteresis in simulations of malaria transmission

NASA Astrophysics Data System (ADS)

Yamana, Teresa K.; Qiu, Xin; Eltahir, Elfatih A. B.

2017-10-01

Malaria transmission is a complex system and in many parts of the world is closely related to climate conditions. However, studies on environmental determinants of malaria generally consider only concurrent climate conditions and ignore the historical or initial conditions of the system. Here, we demonstrate the concept of hysteresis in malaria transmission, defined as non-uniqueness of the relationship between malaria prevalence and concurrent climate conditions. We show the dependence of simulated malaria transmission on initial prevalence and the initial level of human immunity in the population. Using realistic time series of environmental variables, we quantify the effect of hysteresis in a modeled population. In a set of numerical experiments using HYDREMATS, a field-tested mechanistic model of malaria transmission, the simulated maximum malaria prevalence depends on both the initial prevalence and the initial level of human immunity in the population. We found the effects of initial conditions to be of comparable magnitude to the effects of interannual variability in environmental conditions in determining malaria prevalence. The memory associated with this hysteresis effect is longer in high transmission settings than in low transmission settings. Our results show that efforts to simulate and forecast malaria transmission must consider the exposure history of a location as well as the concurrent environmental drivers.

Skillful regional prediction of Arctic sea ice on seasonal timescales

NASA Astrophysics Data System (ADS)

Bushuk, Mitchell; Msadek, Rym; Winton, Michael; Vecchi, Gabriel A.; Gudgel, Rich; Rosati, Anthony; Yang, Xiaosong

2017-05-01

Recent Arctic sea ice seasonal prediction efforts and forecast skill assessments have primarily focused on pan-Arctic sea ice extent (SIE). In this work, we move toward stakeholder-relevant spatial scales, investigating the regional forecast skill of Arctic sea ice in a Geophysical Fluid Dynamics Laboratory (GFDL) seasonal prediction system. Using a suite of retrospective initialized forecasts spanning 1981-2015 made with a coupled atmosphere-ocean-sea ice-land model, we show that predictions of detrended regional SIE are skillful at lead times up to 11 months. Regional prediction skill is highly region and target month dependent and generically exceeds the skill of an anomaly persistence forecast. We show for the first time that initializing the ocean subsurface in a seasonal prediction system can yield significant regional skill for winter SIE. Similarly, as suggested by previous work, we find that sea ice thickness initial conditions provide a crucial source of skill for regional summer SIE.

Internal Migration and Sexual Initiation among Never Married Youths in Nigeria

PubMed Central

Mberu, Blessing Uchenna; White, Michael J

2013-01-01

The high rates of youth migration to urban and economic centers, in the context of persistent poverty and devastating HIV/AIDS burden, raises intricate social policy challenges in developing countries. This study examines patterns of internal migration and sexual initiation among Nigerian youths, using the 2003 Nigeria DHS data, descriptive statistics, Kaplan-Meier survival curves and discrete-time hazard regression models. Migrants generally show stronger association than non-migrants, and urban-urban migrants show the strongest independent association to early sexual initiation. These outcomes underscore that loss of social capital and exposure to sexually lenient urban environment increase youth's propensity to sexual engagement. Other significant covariates are age, gender, ethnic origin, education, independent living arrangement and formal employment. The findings highlight the inadequacy of policy perspectives that neglect complex contextual nuances across groups and the need to address limited livelihood opportunities that fuel youth migration to urban destinations. PMID:21435767

Effect of sample initial magnetic field on the metal magnetic memory NDT result

NASA Astrophysics Data System (ADS)

Moonesan, Mahdi; Kashefi, Mehrdad

2018-08-01

One of the major concerns regarding the use of Metal Magnetic Memory (MMM) technique is the complexity of residual magnetization effect on output signals. The present study investigates the influence of residual magnetic field on stress induced magnetization. To this end, various initial magnetic fields were induced on a low carbon steel sample, and for each level of residual magnetic field, the sample was subjected to a set of 4-point bending tests and, their corresponding MMM signals were collected from the surface of the bended sample using a tailored metal magnetic memory scanning device. Results showed a strong correlation between sample residual magnetic field and its corresponding level of stress induced magnetic field. It was observed that the sample magnetic field increases with applying the bending stress as long as the initial residual magnet field is low (i.e. <117 mG), but starts decreasing with higher levels of initial residual magnetic fields. Besides, effect of bending stress on the MMM output of a notched sample was investigated. The result, again, showed that MMM signals exhibit a drop at stress concentration zone when sample has high level of initial residual magnetic field.

Microstructural Effects on SCC Initiation PWR Primary Water Cold-Worked Alloy 600

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

Zhai, Ziqing; Toloczko, Mychailo B.; Bruemmer, Stephen M.

SCC initiation behavior of one mill annealed alloy 600 plate heat was investigated in simulated PWR primary water under constant load at yield stress with in-situ direct current potential drop (DCPD) monitoring for crack initiation. Twelve specimens were tested at similar cold work levels among which three showed much shorter SCC initiation times (<400 hrs) than the others (>1200 hrs). Post-test examinations revealed that these three specimens all feature an inhomogeneous microstructure where the primary crack always nucleated along the boundary of large elongated grains protruding normally into the gauge. In contrast, such microstructure was either not observed or didmore » not extend deep enough into the gauge in the other specimens exhibiting ~3-6X longer initiation times. In order to better understand the role of this microstructural inhomogeneity in SCC initiation, high-resolution microscopy was performed to compare carbide morphology and strain distribution between the long grains and normal grains, and their potential effects on SCC initiation are discussed in this paper.« less

Perceived realism moderates the relation between sexualized media consumption and permissive sexual attitudes in Dutch adolescents.

PubMed

Baams, Laura; Overbeek, Geertjan; Dubas, Judith Semon; Doornwaard, Suzan M; Rommes, Els; van Aken, Marcel A G

2015-04-01

This study examined whether the development of sexualized media consumption and permissive sexual attitudes would be more strongly interrelated when adolescents perceived sexualized media images as highly realistic. We used data from a three-wave longitudinal sample of 444 Dutch adolescents aged 13-16 years at baseline. Results from parallel process latent growth modeling multigroup analyses showed that higher initial levels of sexualized media consumption were associated with higher initial level of permissive sexual attitudes. Moreover, increases of sexualized media consumption over time were associated with increases of permissive sexual attitudes over time. Considering the moderation by perceived realism, we found these effects only for those who perceived sexualized media as more realistic. Findings for male and female adolescents were similar except for the relations between initial levels and subsequent development. Among male adolescents who perceived sexualized media images to be realistic, higher initial levels of permissive sexual attitudes were related to subsequent less rapid development of sexualized media consumption. For male adolescents who perceived sexualized media to be less realistic, higher initial levels of sexualized media consumption were related to a subsequent less rapid development of permissive sexual attitudes. These relations were not found for female adolescents. Overall, our results suggest that, in male and female adolescents, those with a high level of perceived realism showed a correlated development of sexualized media consumption and permissive sexual attitudes. These findings point to a need for extended information on how to guide adolescents in interpreting and handling sexualized media in everyday life.

Piezoelectrically Initiated Pyrotechnic Igniter

NASA Technical Reports Server (NTRS)

Quince, Asia; Dutton, Maureen; Hicks, Robert; Burnham, Karen

2013-01-01

This innovation consists of a pyrotechnic initiator and piezoelectric initiation system. The device will be capable of being initiated mechanically; resisting initiation by EMF, RF, and EMI (electromagnetic field, radio frequency, and electromagnetic interference, respectively); and initiating in water environments and space environments. Current devices of this nature are initiated by the mechanical action of a firing pin against a primer. Primers historically are prone to failure. These failures are commonly known as misfires or hang-fires. In many cases, the primer shows the dent where the firing pin struck the primer, but the primer failed to fire. In devices such as "T" handles, which are commonly used to initiate the blowout of canopies, loss of function of the device may result in loss of crew. In devices such as flares or smoke generators, failure can result in failure to spot a downed pilot. The piezoelectrically initiated ignition system consists of a pyrotechnic device that plugs into a mechanical system (activator), which on activation, generates a high-voltage spark. The activator, when released, will strike a stack of electrically linked piezo crystals, generating a high-voltage, low-amperage current that is then conducted to the pyro-initiator. Within the initiator, an electrode releases a spark that passes through a pyrotechnic first-fire mixture, causing it to combust. The combustion of the first-fire initiates a primary pyrotechnic or explosive powder. If used in a "T" handle, the primary would ramp the speed of burn up to the speed of sound, generating a shock wave that would cause a high explosive to go "high order." In a flare or smoke generator, the secondary would produce the heat necessary to ignite the pyrotechnic mixture. The piezo activator subsystem is redundant in that a second stack of crystals would be struck at the same time with the same activation force, doubling the probability of a first strike spark generation. If the first activation fails to ignite, the device is capable of multiple attempts. Another unique aspect is in the design of the pyrotechnic device. There is an electrode that aids the generation of a directed spark and the use of a conductive matrix to support the first-fire material so that the spark will penetrate to the second electrode.

Fission yeast translation initiation factor 3 subunit eIF3h is not essential for global translation initiation, but deletion of eif3h+ affects spore formation.

PubMed

Ray, Anirban; Bandyopadhyay, Amitabha; Matsumoto, Tomohiro; Deng, Haiteng; Maitra, Umadas

2008-11-01

The fission yeast Schizosaccharomyces pombe homologue of the p40/eIF3h subunit of mammalian translation initiation factor eIF3 has been characterized in this study. We show that this protein physically associates with the 40S ribosomal particles as a constituent of the multimeric eIF3 protein complex, which consists of all five known eIF3 core subunits (eIF3a, eIF3b, eIF3c, eIF3g and eIF3i) as well as the five non-core subunits (eIF3d, eIF3e, eIF3f, eIF3h and eIF3m) that constitute an eIF3 holocomplex in fission yeast. However, affinity purification of eIF3 from fission yeast cells expressing TAP-tagged eIF3h suggests the presence of distinct forms of eIF3 that differ in their composition of the non-core subunits. Further characterization of eIF3h shows that strains lacking eif3h(+) (eif3hDelta) are viable and show no gross defects, either in vegetative growth or in the rate of in vivo protein synthesis. Polysome profile analysis shows no apparent defects in translation initiation. Furthermore, deletion of eif3h(+) does not affect the ability of the other eIF3 subunits to remain associated with one another in a tight protein complex similar to the situation in wild-type cells. Additionally, we show that human eIF3h can functionally substitute fission yeast eIF3h in complementing in vivo a genetic deletion of eif3h(+). Interestingly, mutant eif3hDelta cells show several prominent phenotypic properties. They are hypersensitive to caffeine and highly defective in meiosis, producing either no spores or incomplete tetrads with a very high frequency. The implications of these results in relation to the functions of eIF3h in Sz. pombe are discussed. (c) 2008 John Wiley & Sons, Ltd.

A systematic study of atmospheric pressure chemical vapor deposition growth of large-area monolayer graphene.

PubMed

Liu, Lixin; Zhou, Hailong; Cheng, Rui; Chen, Yu; Lin, Yung-Chen; Qu, Yongquan; Bai, Jingwei; Ivanov, Ivan A; Liu, Gang; Huang, Yu; Duan, Xiangfeng

2012-01-28

Graphene has attracted considerable interest as a potential material for future electronics. Although mechanical peel is known to produce high quality graphene flakes, practical applications require continuous graphene layers over a large area. The catalyst-assisted chemical vapor deposition (CVD) is a promising synthetic method to deliver wafer-sized graphene. Here we present a systematic study on the nucleation and growth of crystallized graphene domains in an atmospheric pressure chemical vapor deposition (APCVD) process. Parametric studies show that the mean size of the graphene domains increases with increasing growth temperature and CH 4 partial pressure, while the density of domains decreases with increasing growth temperature and is independent of the CH 4 partial pressure. Our studies show that nucleation of graphene domains on copper substrate is highly dependent on the initial annealing temperature. A two-step synthetic process with higher initial annealing temperature but lower growth temperature is developed to reduce domain density and achieve high quality full-surface coverage of monolayer graphene films. Electrical transport measurements demonstrate that the resulting graphene exhibits a high carrier mobility of up to 3000 cm 2 V -1 s -1 at room temperature.

Effects of selected process parameters in extrusion of yam flour (Dioscorea rotundata) on physicochemical properties of the extrudates.

PubMed

Sebio, L; Chang, Y K

2000-04-01

Raw yam (Dioscorea rotundata) flour was cooked and extruded in a Brabender single-screw laboratory scale extruder. Response surface methodology using an incomplete factorial design was applied with various combinations of barrel temperature [100, 125, 150 degrees C], feed moisture content [18, 22, 26%] and screw speed [100, 150, 200 rpm]. Initial viscosity at 30 degrees C, water solubility index, expansion and hardness were determined. The highest values of initial viscosity were at the highest barrel temperatures and the highest moisture contents. At high feed moisture content and high barrel temperatures the yam extrudate flour showed the greatest values of water solubility index. The physical properties of the extruded product showed that at high temperature the lower the moisture content the greater the expansion index. Hardness was influenced directly by moisture content and inversely by extrusion temperature. The extrusion of yam flour led to the production of snacks and pre-gelatinized flours of diverse properties. Also extruded yam flour can be successfully used in the preparation of 'futu' (pre-cooked compact dough), a yam-based food, popular in Western Africa.

Dispositional mindfulness and semantic integration of emotional words: Evidence from event-related brain potentials.

PubMed

Dorjee, Dusana; Lally, Níall; Darrall-Rew, Jonathan; Thierry, Guillaume

2015-08-01

Initial research shows that mindfulness training can enhance attention and modulate the affective response. However, links between mindfulness and language processing remain virtually unexplored despite the prominent role of overt and silent negative ruminative speech in depressive and anxiety-related symptomatology. Here, we measured dispositional mindfulness and recorded participants' event-related brain potential responses to positive and negative target words preceded by words congruent or incongruent with the targets in terms of semantic relatedness and emotional valence. While the low mindfulness group showed similar N400 effect pattern for positive and negative targets, high dispositional mindfulness was associated with larger N400 effect to negative targets. This result suggests that negative meanings are less readily accessible in people with high dispositional mindfulness. Furthermore, high dispositional mindfulness was associated with reduced P600 amplitudes to emotional words, suggesting less post-analysis and attentional effort which possibly relates to a lower inclination to ruminate. Overall, these findings provide initial evidence on associations between modifications in language systems and mindfulness. Copyright © 2015 Elsevier Ireland Ltd and the Japan Neuroscience Society. All rights reserved.

One-pot synthesis of carbon-coated nanosized LiTi2(PO4)3 as anode materials for aqueous lithium ion batteries

NASA Astrophysics Data System (ADS)

Liu, Zhantao; Qin, Xusong; Xu, Hui; Chen, Guohua

2015-10-01

In this study, a one-pot sintering process incorporating sol-gel preparation route and in-situ carbon coating was proposed for the synthesis of carbon-coated nanosized LiTi2(PO4)3. Experimental results show that the prepared LiTi2(PO4)3 particles are of high crystallinity and well-coated by turbostratic carbon. Attributed to nanosized particles and enhanced conductivity provided by turbostratic carbon coating, the carbon-coated LiTi2(PO4)3 showed high rate performance and good cycling life in aqueous electrolyte. Particularly, the carbon-coated LiTi2(PO4)3 exhibited initial specific capacities of 103 and 89 mAh g-1, and retained 80.6% and 97% of the initial capacities after 120 cycles at 1C and 10C in aqueous electrolyte, respectively. The high rate performance and good cycling life of carbon-coated LiTi2(PO4)3 in aqueous electrolyte reveal its potential as negative electrode in aqueous lithium-ion batteries for electric vehicles and industrial-scale energy storage systems.

A 31-year-old man with bilateral blurry vision and floaters.

PubMed

Abazari, Azin; Kaplowitz, Kevin; Sibony, Patrick

2015-01-01

We report a case of bilateral multifocal retinochoroiditis and bilateral optic disc edema in a patient with cat-scratch disease from Bartonella henselae. The patient initially had negative serologic testing. Repeat testing showed a markedly increased IgG and IgM convalescent titer and the development of a branch retinal artery and vein occlusion. In patients for whom there is a high clinical suspicion of cat-scratch disease, a convalescent titer should be obtained 2-3 weeks following a negative initial result.

Influence of temporal pressure constraint on the biomechanical organization of gait initiation made with or without an obstacle to clear.

PubMed

Yiou, Eric; Fourcade, Paul; Artico, Romain; Caderby, Teddy

2016-06-01

Many daily motor tasks have to be performed under a temporal pressure constraint. This study aimed to explore the influence of such constraint on motor performance and postural stability during gait initiation. Young healthy participants initiated gait at maximal velocity under two conditions of temporal pressure: in the low-pressure condition, gait was self-initiated (self-initiated condition, SI); in the high-pressure condition, it was initiated as soon as possible after an acoustic signal (reaction-time condition, RT). Gait was initiated with and without an environmental constraint in the form of an obstacle to be cleared placed in front of participants. Results showed that the duration of postural adjustments preceding swing heel-off ("anticipatory postural adjustments", APAs) was shorter, while their amplitude was larger in RT compared to SI. These larger APAs allowed the participants to reach equivalent postural stability and motor performance in both RT and SI. In addition, the duration of the execution phase of gait initiation increased greatly in the condition with an obstacle to be cleared (OBST) compared to the condition without an obstacle (NO OBST), thereby increasing lateral instability and thus involving larger mediolateral APA. Similar effects of temporal pressure were obtained in NO OBST and OBST. This study shows the adaptability of the postural system to temporal pressure in healthy young adults initiating gait. The outcome of this study may provide a basis for better understanding the aetiology of balance impairments with the risk of falling in frail populations while performing daily complex tasks involving a whole-body progression.

Initial performance results for high-aspect ratio gold MEMS deformable mirrors

NASA Astrophysics Data System (ADS)

Fernández, Bautista; Kubby, Joel

2009-02-01

The fabrication and initial performance results of high-aspect ratio 3-dimensional Micro-Electro-Mechanical System (MEMS) Deformable Mirrors (DM) for Adaptive Optics (AO) will be discussed. The DM systems were fabricated out of gold, and consist of actuators bonded to a continuous face sheet, with different boundary conditions. DM mirror displacements vs. voltage have been measured with a white light interferometer and the corresponding results compared to Finite Element Analysis (FEA) simulations. Interferometer scans of a DM have shown that ~9.4um of stroke can be achieved with low voltage, thus showing that this fabrication process holds promise in the manufacturing of future MEMS DM's for the next generation of extremely large telescopes.

Understanding the Interaction of Pluronics L61 and L64 with a DOPC Lipid Bilayer: An Atomistic Molecular Dynamics Study

DOE PAGES

Ileri Ercan, Nazar; Stroeve, Pieter; Tringe, Joseph W.; ...

2016-09-13

In this paper, we investigate the interactions of Pluronics L61 and L64 with a dioleylphosphatidylcholine (DOPC) lipid bilayer by atomistic molecular dynamics simulations using the all-atom OPLS force field. Our results show that the initial configuration of the polymer with respect to the bilayer determines its final conformation within the bilayer. When the polymer is initially placed at the lipid/water interface, we observe partial insertion of the polymer in a U-shaped conformation. On the other hand, when the polymer is centered at the bilayer, it stabilizes to a transmembrane state, which facilitates water transport across the bilayer. We show thatmore » membrane thickness decreases while its fluidity increases in the presence of Pluronics. When the polymer concentration inside the bilayer is high, pore formation is initiated with L64. Finally, our results show good agreement with existing experimental data and reveal that the hydrophilic/lipophilic balance of the polymer plays a critical role in the interaction mechanisms as well as in the dynamics of Pluronics with and within the bilayer.« less

Test results of the Chrysler upgraded automotive gas turbine engine: Initial design

NASA Technical Reports Server (NTRS)

Horvath, D.; Ribble, G. H., Jr.; Warren, E. L.; Wood, J. C.

1981-01-01

The upgraded engine as built to the original design was deficient in power and had excessive specific fuel consumption. A high instrumented version of the engine was tested to identify the sources of the engine problems. Analysis of the data shows the major problems to be low compressor and power turbine efficiency and excessive interstage duct losses. In addition, high HC and CO emission were measured at idle, and high NOx emissions at high energy speeds.

Proteolysis-a characteristic of tumor-initiating cells in murine metastatic breast cancer

PubMed Central

Hillebrand, Larissa E.; Bengsch, Fee; Hochrein, Jochen; Hülsdünker, Jan; Bender, Julia; Follo, Marie; Busch, Hauke; Boerries, Melanie; Reinheckel, Thomas

2016-01-01

Tumor initiating cells (TICs) have been identified and functionally characterized in hematological malignancies as well as in solid tumors such as breast cancer. In addition to their high tumor-initiating potential, TICs are founder cells for metastasis formation and are involved in chemotherapy resistance. In this study we explored molecular pathways which enable this tumor initiating potential for a cancer cell subset of the transgenic MMTV-PyMT mouse model for metastasizing breast cancer. The cell population, characterized by the marker profile CD24+CD90+CD45−, showed a high tumorigenicity compared to non-CD24+CD90+CD45− cancer cells in colony formation assays, as well as upon orthotopic transplantation into the mammary fat pad of mice. In addition, these orthotopically grown CD24+CD90+CD45− TICs metastasized to the lungs. The transcriptome of TICs freshly isolated from primary tumors by cell sorting was compared with that of sorted non-CD24+CD90+CD45− cancer cells by RNA-seq. In addition to more established TIC signatures, such as epithelial-to-mesenchymal transition or mitogen signaling, an upregulated gene set comprising several classes of proteolytic enzymes was uncovered in the TICs. Accordingly, TICs showed high intra- and extracellular proteolytic activity. Application of a broad range of protease inhibitors to TICs in a colony formation assay reduced anchorage independent growth and had an impact on colony morphology in 3D cell culture assays. We conclude that CD24+CD90+CD45− cells of the MMTV- PyMT mouse model possess an upregulated proteolytic signature which could very well represent a functional hallmark of metastatic TICs from mammary carcinomas. PMID:27542270

Influence of Torsion Effect on the Mechanical Characteristics of Reinforced Concrete Column

NASA Astrophysics Data System (ADS)

Wang, Debin; Fan, Guoxi

2017-11-01

The purpose of this paper is to study the effect of torsional effect and loading rate on the flexural capacity of RC members. Based on the fiber model of finite element software ABAQUS, a model has been established with the consideration of the strain rate sensitivity of steel and concrete. The model is used to reflect the influence of the rotational component of ground motion by applying the initial angular displacement. The mechanical properties of RC columns under monotonic loads are simulated. The simulation results show that there has been a decrease in the carrying capacity and initial stiffness of RC columns for high initial torsion angle. With the increase of initial torsion angle, the influence of loading rate on RC columns gradually increases.

Demand behavior and empathic accuracy in observed conflict interactions in couples.

PubMed

Hinnekens, Céline; Ickes, William; Schryver, Maarten De; Verhofstadt, Lesley L

2016-01-01

The study reported in this research note sought to extend the research on motivated empathic accuracy by exploring whether intimate partners who are highly motivated to induce change in their partner during conflicts will be more empathically accurate than partners who are less motivated. In a laboratory experiment, the partners within 26 cohabiting couples were randomly assigned the role of conflict initiator. The partners provided questionnaire data, participated in a videotaped conflict interaction, and completed a video-review task. More blaming behavior was associated with higher levels of empathic accuracy, irrespective of whether one was the conflict initiator or not. The results also showed a two-way interaction indicating that initiators who applied more pressure on their partners to change were less empathically accurate than initiators who applied less pressure, whereas their partners could counter this pressure when they could accurately "read" the initiator's thoughts and feelings.

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

Rison, William; Krehbiel, Paul R.; Stock, Michael G.

A long-standing but fundamental question in lightning studies concerns how lightning is initiated inside storms, given the absence of physical conductors. The issue has revolved around the question of whether the discharges are initiated solely by conventional dielectric breakdown or involve relativistic runaway electron processes. Here we report observations of a relatively unknown type of discharge, called fast positive breakdown, that is the cause of high-power discharges known as narrow bipolar events. We find that the breakdown has a wide range of strengths and is the initiating event of numerous lightning discharges. It appears to be purely dielectric in naturemore » and to consist of a system of positive streamers in a locally intense electric field region. It initiates negative breakdown at the starting location of the streamers, which leads to the ensuing flash. The observations show that many or possibly all lightning flashes are initiated by fast positive breakdown.« less

Predicting High Imaging Utilization Based on Initial Radiology Reports: A Feasibility Study of Machine Learning.

PubMed

Hassanpour, Saeed; Langlotz, Curtis P

2016-01-01

Imaging utilization has significantly increased over the last two decades, and is only recently showing signs of moderating. To help healthcare providers identify patients at risk for high imaging utilization, we developed a prediction model to recognize high imaging utilizers based on their initial imaging reports. The prediction model uses a machine learning text classification framework. In this study, we used radiology reports from 18,384 patients with at least one abdomen computed tomography study in their imaging record at Stanford Health Care as the training set. We modeled the radiology reports in a vector space and trained a support vector machine classifier for this prediction task. We evaluated our model on a separate test set of 4791 patients. In addition to high prediction accuracy, in our method, we aimed at achieving high specificity to identify patients at high risk for high imaging utilization. Our results (accuracy: 94.0%, sensitivity: 74.4%, specificity: 97.9%, positive predictive value: 87.3%, negative predictive value: 95.1%) show that a prediction model can enable healthcare providers to identify in advance patients who are likely to be high utilizers of imaging services. Machine learning classifiers developed from narrative radiology reports are feasible methods to predict imaging utilization. Such systems can be used to identify high utilizers, inform future image ordering behavior, and encourage judicious use of imaging. Copyright © 2016 The Association of University Radiologists. Published by Elsevier Inc. All rights reserved.

SU-F-T-164: Investigation of PRESAGE Formulation On Signal Quenching in a Proton Beam

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

Carroll, M; Alqathami, M; Ibbott, G

2016-06-15

Purpose: The radiochromic polyurethane PRESAGE by Heuris Pharma has had limited applications with protons because of a dose response dependence on LET resulting in signal quenching in the Bragg peak. This is due to the radical initiator, a halocarbon, radically recombining in high-LET irradiations. This study investigated the use of alternative halocarbons at various chemical concentrations to determine their significance in signal quenching. Methods: PRESAGE was manufactured in-house and cast in small volume cuvettes (1×1×4cm^3). Several compositions were evaluated to determine the influence of the radical initiator component. Mixtures contained one of two halocarbons, chloroform or bromoform, at concentrations ofmore » 5%/10%/15%(w/w). A large volume, cylindrical PRESAGE dosimeter made following the mixture described by Heuris Pharma, 4cm(D)×8.5cm(H), was irradiated with 200-MeV protons to study regions of low- and high-LET along a 10cm spread out Bragg peak isodose profile. Depths corresponding to regions of low quenching (<3%) and high quenching (>20%) were determined. These depths were used for cuvette placement in a solid water phantom. Samples of each formulation were placed at each depth and irradiated to doses between 0 and 10Gy. Results: The cuvettes indicated different levels of quenching for different radical initiator types, concentrations, and total doses. Chloroform formulations showed reduced quenching from 29%(5%-w/w) to 21%(15%-w/w) while bromoform reduced quenching from 27%(5%-w/w) to 17%(15%-w/w). The reduction in quenching was found to be non-linear with concentration of radical initiator. A quenching dose-dependency was also found that changed with formulation. In all cases, quenching was relatively consistent from 0–5Gy but increased at 10Gy. The quenching decreased as concentrations of radical initiator increased. Conclusion: The radical initiator component in PRESAGE is correlated with the signal quenching observed in proton irradiations and formulation adjustments show promise as a method of reducing this quenching. Future work will further investigate concentration limits and optimize the formulation. Grant number 5RO1CA100835.« less

SEMICONDUCTOR TECHNOLOGY: Influence of nitrogen dose on the charge density of nitrogen-implanted buried oxide in SOI wafers

NASA Astrophysics Data System (ADS)

Zhongshan, Zheng; Zhongli, Liu; Ning, Li; Guohua, Li; Enxia, Zhang

2010-02-01

To harden silicon-on-insulator (SOI) wafers fabricated using separation by implanted oxygen (SIMOX) to total-dose irradiation, the technique of nitrogen implantation into the buried oxide (BOX) layer of SIMOX wafers can be used. However, in this work, it has been found that all the nitrogen-implanted BOX layers reveal greater initial positive charge densities, which increased with increasing nitrogen implantation dose. Also, the results indicate that excessively large nitrogen implantation dose reduced the radiation tolerance of BOX for its high initial positive charge density. The bigger initial positive charge densities can be ascribed to the accumulation of implanted nitrogen near the Si-BOX interface after annealing. On the other hand, in our work, it has also been observed that, unlike nitrogen-implanted BOX, all the fluorine-implanted BOX layers show a negative charge density. To obtain the initial charge densities of the BOX layers, the tested samples were fabricated with a metal-BOX-silicon (MBS) structure based on SIMOX wafers for high-frequency capacitance-voltage (C-V) analysis.

Optimization of Acid Black 172 decolorization by electrocoagulation using response surface methodology

PubMed Central

2012-01-01

This paper utilizes a statistical approach, the response surface optimization methodology, to determine the optimum conditions for the Acid Black 172 dye removal efficiency from aqueous solution by electrocoagulation. The experimental parameters investigated were initial pH: 4–10; initial dye concentration: 0–600 mg/L; applied current: 0.5-3.5 A and reaction time: 3–15 min. These parameters were changed at five levels according to the central composite design to evaluate their effects on decolorization through analysis of variance. High R2 value of 94.48% shows a high correlation between the experimental and predicted values and expresses that the second-order regression model is acceptable for Acid Black 172 dye removal efficiency. It was also found that some interactions and squares influenced the electrocoagulation performance as well as the selected parameters. Optimum dye removal efficiency of 90.4% was observed experimentally at initial pH of 7, initial dye concentration of 300 mg/L, applied current of 2 A and reaction time of 9.16 min, which is close to model predicted (90%) result. PMID:23369574

High-resolution MRI vessel wall imaging: spatial and temporal patterns of reversible cerebral vasoconstriction syndrome and central nervous system vasculitis.

PubMed

Obusez, E C; Hui, F; Hajj-Ali, R A; Cerejo, R; Calabrese, L H; Hammad, T; Jones, S E

2014-08-01

High-resolution MR imaging is an emerging tool for evaluating intracranial artery disease. It has an advantage of defining vessel wall characteristics of intracranial vascular diseases. We investigated high-resolution MR imaging arterial wall characteristics of CNS vasculitis and reversible cerebral vasoconstriction syndrome to determine wall pattern changes during a follow-up period. We retrospectively reviewed 3T-high-resolution MR imaging vessel wall studies performed on 26 patients with a confirmed diagnosis of CNS vasculitis and reversible cerebral vasoconstriction syndrome during a follow-up period. Vessel wall imaging protocol included black-blood contrast-enhanced T1-weighted sequences with fat suppression and a saturation band, and time-of-flight MRA of the circle of Willis. Vessel wall characteristics including enhancement, wall thickening, and lumen narrowing were collected. Thirteen patients with CNS vasculitis and 13 patients with reversible cerebral vasoconstriction syndrome were included. In the CNS vasculitis group, 9 patients showed smooth, concentric wall enhancement and thickening; 3 patients had smooth, eccentric wall enhancement and thickening; and 1 patient was without wall enhancement and thickening. Six of 13 patients had follow-up imaging; 4 patients showed stable smooth, concentric enhancement and thickening; and 2 patients had resoluton of initial imaging findings. In the reversible cerebral vasoconstriction syndrome group, 10 patients showed diffuse, uniform wall thickening with negligible-to-mild enhancement. Nine patients had follow-up imaging, with 8 patients showing complete resolution of the initial findings. Postgadolinium 3T-high-resolution MR imaging appears to be a feasible tool in differentiating vessel wall patterns of CNS vasculitis and reversible cerebral vasoconstriction syndrome changes during a follow-up period. © 2014 by American Journal of Neuroradiology.

Crack-tip-opening angle measurements and crack tunneling under stable tearing in thin sheet 2024-T3 aluminum alloy

NASA Technical Reports Server (NTRS)

Dawicke, D. S.; Sutton, M. A.

1993-01-01

The stable tearing behavior of thin sheets 2024-T3 aluminum alloy was studied for middle crack tension specimens having initial cracks that were: flat cracks (low fatigue stress) and 45 degrees through-thickness slant cracks (high fatigue stress). The critical crack-tip-opening angle (CTOA) values during stable tearing were measured by two independent methods, optical microscopy and digital image correlation. Results from the two methods agreed well. The CTOA measurements and observations of the fracture surfaces showed that the initial stable tearing behavior of low and high fatigue stress tests is significantly different. The cracks in the low fatigue stress tests underwent a transition from flat-to-slant crack growth, during which the CTOA values were high and significant crack tunneling occurred. After crack growth equal to about the thickness, CTOA reached a constant value of 6 deg and after crack growth equal to about twice the thickness, crack tunneling stabilized. The initial high CTOA values, in the low fatigue crack tests, coincided with large three-dimensional crack front shape changes due to a variation in the through-thickness crack tip constraint. The cracks in the high fatigue stress tests reach the same constant CTOA value after crack growth equal to about the thickness, but produced only a slightly higher CTOA value during initial crack growth. For crack growth on the 45 degree slant, the crack front and local field variables are still highly three-dimensional. However, the constant CTOA values and stable crack front shape may allow the process to be approximated with two-dimensional models.

CEA monitoring of palliative treatment for colorectal carcinoma.

PubMed Central

Herrera, M A; Chu, T M; Holyoke, E D; Mittelman, A

1977-01-01

Palliative treatment was applied to 131 cases of unresectable or palliatively resected colorectal carcinoma being monitored with serial CEA determinations. There were 84 instances of disease progression with 67 (80%) of them showing an increase in CEA above pretreatment levels or maintaining high levels, and 17 (20%) showing a fall when compared to pretreatment values or maintaining low initial values. There was a clear-cut regression of the disease in only 9 instances. In all 9, the CEA clearly dropped or maintained low valles throughout the period of regression. No patient in regression had a rise or maintained an elevated CEA level. These changes in CEA followed closely the clinical response of our patient to the use of a particular agent, although for the Nitrosourea compounds there may be a tendency to lower the CEA regardless of the patient's tumor response to the drug. This could be due to the fact that the Nitrosoureas produce a diffuse block of cellular activity, both at the nucleous and cytoplasm; while other compounds act as alkylating agents or by inhibition of enzymes involved in the metabolism of nucleic acids (i.e., 5-FU inhibiting thymidylate synthetase). In general, longer survival was found in those patients who had initially lower levels of CEA as compared to those with high initial levels. The patients with a favorable CEA response to the treatment (falling CEA or maintained low value), even in many who did not show a clinical response had a longer survival than the group with rising or stable high levels. The main value in CEA monitoring of patients resides in its correlation with the amount of disease present and then its ability to detect progression of tumor mass which is not clinically measurable. PMID:64132

Biological insights into the expression of translation initiation factors from recombinant CHOK1SV cell lines and their relationship to enhanced productivity.

PubMed

Mead, Emma J; Masterton, Rosalyn J; Feary, Marc; Obrezanova, Olga; Zhang, Lin; Young, Robert; Smales, C Mark

2015-12-15

Translation initiation is on the critical pathway for the production of monoclonal antibodies (mAbs) by mammalian cells. Formation of a closed loop structure comprised of mRNA, a number of eukaryotic initiation factors (eIFs) and ribosomal proteins has been proposed to aid re-initiation of translation and therefore increase global translational efficiency. We have determined mRNA and protein levels of the key components of the closed loop, eIFs (eIF3a, eIF3b, eIF3c, eIF3h, eIF3i and eIF4G1), poly(A)-binding protein (PABP) 1 and PABP-interacting protein 1 (PAIP1), across a panel of 30 recombinant mAb-producing GS-CHOK1SV cell lines with a broad range of growth characteristics and production levels of a model recombinant mAb. We have used a multi-level statistical approach to investigate the relationship between key performance indicators (cell growth and recombinant antibody productivity) and the intracellular amounts of target translation initiation factor proteins and the mRNAs encoding them. We show that high-producing cell lines maintain amounts of the translation initiation factors involved in the formation of the closed loop mRNA, maintaining these proteins at appropriate levels to deliver enhanced recombinant protein production. We then utilize knowledge of the amounts of these factors to build predictive models for and use cluster analysis to identify, high-producing cell lines. The present study therefore defines the translation initiation factor amounts that are associated with highly productive recombinant GS-CHOK1SV cell lines that may be targets for screening highly productive cell lines or to engineer new host cell lines with the potential for enhanced recombinant antibody productivity. © 2015 Authors; published by Portland Press Limited.

ECL-IAA and ECL-GADA Can Identify High-Risk Single Autoantibody-Positive Relatives in the TrialNet Pathway to Prevention Study

PubMed Central

Fouts, Alexandra; Miao, Dongmei; Zhao, Zhiyuan; Dong, Fran; Sosenko, Jay; Gottlieb, Peter; Rewers, Marian J.

2016-01-01

Abstract Background: Relatives with single positive islet autoantibodies have a much lower risk of progression to diabetes than those with multiple autoantibodies. Materials and Methods: TrialNet subjects positive for single autoantibody to insulin (mIAA) (n = 50) or single autoantibody to glutamic acid decarboxylase (GADA) (n = 50) were analyzed using new electrochemiluminescence (ECL) assays (ECL-IAA and ECL-GADA, respectively) at their initial visit and longitudinally over time. Affinity assays were performed on a subset of single autoantibody-positive subjects at initial and most recent visits. Results: After a mean follow-up of 5.3 years, 20 subjects developed type 1 diabetes. Among either single GADA or single mIAA subjects, those who were positive in the ECL assay showed higher affinity at the initial visit, and affinity results stayed consistent over time. No converting events from low to high or high to low affinity were seen over time. Conclusions: Confirmed positivity for ECL is associated with high affinity and can help staging of risk for type 1 diabetes in single autoantibody-positive subjects. PMID:26991969

The 5′ Untranslated Region of the Human T-Cell Lymphotropic Virus Type 1 mRNA Enables Cap-Independent Translation Initiation

PubMed Central

Olivares, Eduardo; Landry, Dori M.; Cáceres, C. Joaquín; Pino, Karla; Rossi, Federico; Navarrete, Camilo; Huidobro-Toro, Juan Pablo; Thompson, Sunnie R.

2014-01-01

ABSTRACT The human T-cell leukemia virus type 1 (HTLV-1) is a complex human retrovirus that causes adult T cell leukemia and of HTLV-associated myelopathy/tropical spastic paraparesis. The mRNA of some complex retroviruses, including the human and simian immunodeficiency viruses (HIV and SIV), can initiate translation using a canonical cap-dependent mechanism or through an internal ribosome entry site (IRES). In this study, we present strong evidence showing that like HIV-1 and SIV, the 5′-untranslated region (5′UTR) of the HTLV-1 full-length mRNA harbors an IRES. Cap-independent translational activity was evaluated and demonstrated using dual luciferase bicistronic mRNAs in rabbit reticulocyte lysate, in mammalian cell culture, and in Xenopus laevis oocytes. Characterization of the HTLV-1 IRES shows that its activity is dependent on the ribosomal protein S25 (RPS25) and that its function is highly sensitive to the drug edeine. Together, these findings suggest that the 5′UTR of the HTLV-1 full-length mRNA enables internal recruitment of the eukaryotic translation initiation complex. However, the recognition of the initiation codon requires ribosome scanning. These results suggest that, after internal recruitment by the HTLV-1 IRES, a scanning step takes place for the 40S ribosomal subunit to be positioned at the translation initiation codon. IMPORTANCE The mechanism by which retroviral mRNAs recruit the 40S ribosomal subunit internally is not understood. This study provides new insights into the mechanism of translation initiation used by the human T-cell lymphotropic virus type 1 (HTLV-1). The results show that the HTLV-1 mRNA can initiate translation via a noncanonical mechanism mediated by an internal ribosome entry site (IRES). This study also provides evidence showing the involvement of cellular proteins in HTLV-1 IRES-mediated translation initiation. Together, the data presented in this report significantly contribute to the understanding of HTLV-1 gene expression. PMID:24623421

Safety and immunogenicity of a booster dose of a 3-antigen Staphylococcus aureus vaccine (SA3Ag) in healthy adults: A randomized phase 1 study.

PubMed

Marshall, Helen; Nissen, Michael; Richmond, Peter; Shakib, Sepehr; Jiang, Qin; Cooper, David; Rill, Denise; Baber, James; Eiden, Joseph; Gruber, William C; Jansen, Kathrin U; Anderson, Annaliesa S; Zito, Edward T; Girgenti, Douglas

2016-11-01

A 2-stage, phase 1, randomized, placebo-controlled study in healthy adults to assess immunogenicity and safety of a booster dose at three dose levels of a 3-antigen Staphylococcus aureus vaccine (SA3Ag) containing recombinant clumping factor A (ClfA) and capsular polysaccharides 5 and 8 (CP5 and CP8) conjugated to a diphtheria toxoid. Six months after initial single vaccination, in Stage 2, SA3Ag recipients were randomized (1:1) to booster vaccination or placebo, while Stage 1 placebo recipients received placebo again. Pre- and post-vaccination blood samples were analyzed. In Stage 2 (n = 345), pre-booster CP5 and CP8 titers remained high with no increase post-booster. ClfA titers remained high after initial vaccination and increased post-booster, approaching the peak response to the initial dose. Post-booster local reactions were more frequent and of greater severity than reported after the initial vaccination, particularly for the high-dose level recipients. Post hoc analysis showed no dose-response pattern and no obvious association between diphtheria toxoid titers and local reactions after initial or booster vaccination. Immune responses after the initial vaccination persisted for the 12 months studied, with little additional response after the booster dose at 6 months. Post-booster injection site reactions were more frequent and more severe but self-limiting. CLINICALTRIALS. NCT01018641. Copyright © 2016 The British Infection Association. Published by Elsevier Ltd. All rights reserved.

I've Fallen and I Can't Get up: Can High-Ability Students Recover from Early Mistakes in CAT?

ERIC Educational Resources Information Center

Rulison, Kelly L.; Loken, Eric

2009-01-01

A difficult result to interpret in Computerized Adaptive Tests (CATs) occurs when an ability estimate initially drops and then ascends continuously until the test ends, suggesting that the true ability may be higher than implied by the final estimate. This study explains why this asymmetry occurs and shows that early mistakes by high-ability…

M x Mn 8O 16 (M = Ag or K) as promising cathode materials for secondary Mg based batteries: the role of the cation M

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

Huang, Jianping; Poyraz, Altug S.; Takeuchi, Kenneth J.

2016-01-01

2 × 2 tunneled M xMn 8O 16(M = Ag or K) materials delivered high initial capacities in Mg based electrolyte, and K xMn 8O 16 showed high cycle stability with a reversible capacity of >170 mA h g -1after 20 cycles.

Model for assessment of the velocity and force at the start of sprint race.

PubMed

Janjić, Nataša J; Kapor, Darko V; Doder, Dragan V; Petrović, Aleksandar; Jarić, Slobodan

2017-02-01

A mathematical model was developed for the assessment of the starting velocity and initial velocity and force of a 100-m sprint, based on a non-homogeneous differential equation with the air resistance proportional to the velocity, and the initial conditions for [Formula: see text], [Formula: see text]The use of this model requires the measurement of reaction time and segmental velocities over the course of the race. The model was validated by comparison with the data obtained from 100-m sprints of men: Carl Lewis (1988), Maurice Green (2001) and Usain Bolt (2009), and women: Florence Griffith-Joyner, Evelyn Ashford and Drechsler Heike (1988) showing a high level of agreement. Combined with the previous work of the authors, the present model allows for the assessment of important physical abilities, such as the exertion of a high starting force, development of high starting velocity and, later on, maximisation of the peak running velocity. These data could be of importance for practitioners to identify possible weaknesses and refine training methods for sprinters and other athletes whose performance depend on rapid movement initiations.

Lightning discharges produced by wind turbines

NASA Astrophysics Data System (ADS)

Montanyà, Joan; van der Velde, Oscar; Williams, Earle R.

2014-02-01

New observations with a 3-D Lightning Mapping Array and high-speed video are presented and discussed. The first set of observations shows that under certain thunderstorm conditions, wind turbine blades can produce electric discharges at regular intervals of 3 s in relation to its rotation, over periods of time that range from a few minutes up to hours. This periodic effect has not been observed in static towers indicating that the effect of rotation is playing a critical role. The repeated discharges can occur tens of kilometers away from electrically active thunderstorm areas and may or may not precede a fully developed upward lightning discharge from the turbine. Similar to rockets used for triggering lightning, the fast movement of the blade tip plays an important role on the initiation of the discharge. The movement of the rotor blades allows the tip to "runaway" from the generated corona charge. The second observation is an uncommon upward/downward flash triggered by a wind turbine. In that flash, a negative upward leader was initiated from a wind turbine without preceding lightning activity. The flash produced a negative cloud-to-ground stroke several kilometers from the initiation point. The third observation corresponds to a high-speed video record showing simultaneous upward positive leaders from a group of wind turbines triggered by a preceding intracloud flash. The fact that multiple leaders develop simultaneously indicates a poor shielding effect among them. All these observations provide some special features on the initiation of lightning by nonstatic and complex tall structures.

Clustering Categorical Data Using Community Detection Techniques

PubMed Central

2017-01-01

With the advent of the k-modes algorithm, the toolbox for clustering categorical data has an efficient tool that scales linearly in the number of data items. However, random initialization of cluster centers in k-modes makes it hard to reach a good clustering without resorting to many trials. Recently proposed methods for better initialization are deterministic and reduce the clustering cost considerably. A variety of initialization methods differ in how the heuristics chooses the set of initial centers. In this paper, we address the clustering problem for categorical data from the perspective of community detection. Instead of initializing k modes and running several iterations, our scheme, CD-Clustering, builds an unweighted graph and detects highly cohesive groups of nodes using a fast community detection technique. The top-k detected communities by size will define the k modes. Evaluation on ten real categorical datasets shows that our method outperforms the existing initialization methods for k-modes in terms of accuracy, precision, and recall in most of the cases. PMID:29430249

Observations of narrow bipolar events reveal how lightning is initiated in thunderstorms

DOE PAGES

Rison, William; Krehbiel, Paul R.; Stock, Michael G.; ...

2016-02-15

A long-standing but fundamental question in lightning studies concerns how lightning is initiated inside storms, given the absence of physical conductors. The issue has revolved around the question of whether the discharges are initiated solely by conventional dielectric breakdown or involve relativistic runaway electron processes. Here we report observations of a relatively unknown type of discharge, called fast positive breakdown, that is the cause of high-power discharges known as narrow bipolar events. We find that the breakdown has a wide range of strengths and is the initiating event of numerous lightning discharges. It appears to be purely dielectric in naturemore » and to consist of a system of positive streamers in a locally intense electric field region. It initiates negative breakdown at the starting location of the streamers, which leads to the ensuing flash. The observations show that many or possibly all lightning flashes are initiated by fast positive breakdown.« less

A Gompertz population model with Allee effect and fuzzy initial values

NASA Astrophysics Data System (ADS)

Amarti, Zenia; Nurkholipah, Nenden Siti; Anggriani, Nursanti; Supriatna, Asep K.

2018-03-01

Growth and population dynamics models are important tools used in preparing a good management for society to predict the future of population or species. This has been done by various known methods, one among them is by developing a mathematical model that describes population growth. Models are usually formed into differential equations or systems of differential equations, depending on the complexity of the underlying properties of the population. One example of biological complexity is Allee effect. It is a phenomenon showing a high correlation between very small population size and the mean individual fitness of the population. In this paper the population growth model used is the Gompertz equation model by considering the Allee effect on the population. We explore the properties of the solution to the model numerically using the Runge-Kutta method. Further exploration is done via fuzzy theoretical approach to accommodate uncertainty of the initial values of the model. It is known that an initial value greater than the Allee threshold will cause the solution rises towards carrying capacity asymptotically. However, an initial value smaller than the Allee threshold will cause the solution decreases towards zero asymptotically, which means the population is eventually extinct. Numerical solutions show that modeling uncertain initial value of the critical point A (the Allee threshold) with a crisp initial value could cause the extinction of population of a certain possibilistic degree, depending on the predetermined membership function of the initial value.

Multipoint propagators for non-Gaussian initial conditions

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

Bernardeau, Francis; Sefusatti, Emiliano; Crocce, Martin

2010-10-15

We show here how renormalized perturbation theory calculations applied to the quasilinear growth of the large-scale structure can be carried on in presence of primordial non-Gaussian (PNG) initial conditions. It is explicitly demonstrated that the series reordering scheme proposed in Bernardeau, Crocce, and Scoccimarro [Phys. Rev. D 78, 103521 (2008)] is preserved for non-Gaussian initial conditions. This scheme applies to the power spectrum and higher-order spectra and is based on a reorganization of the contributing terms into the sum of products of multipoint propagators. In case of PNG, new contributing terms appear, the importance of which is discussed in themore » context of current PNG models. The properties of the building blocks of such resummation schemes, the multipoint propagators, are then investigated. It is first remarked that their expressions are left unchanged at one-loop order irrespective of statistical properties of the initial field. We furthermore show that the high-momentum limit of each of these propagators can be explicitly computed even for arbitrary initial conditions. They are found to be damped by an exponential cutoff whose expression is directly related to the moment generating function of the one-dimensional displacement field. This extends what had been established for multipoint propagators for Gaussian initial conditions. Numerical forms of the cutoff are shown for the so-called local model of PNG.« less

Stability Study on Steel Structural Columns with Initial Blast Damage under High Temperatures

NASA Astrophysics Data System (ADS)

Baoxin, Qi; Yan, Shi; Li, Peng

2018-03-01

Blast may bring light-weight steel columns with initial damages, resulting in lowering its critical fire-resistance temperature whose reduced amplitude is relevant to the form and degree of the damages. Finite element analysis software ANSYS was used in the paper to analyze the issue of the fire-resistance temperature of the column with the blast damages, and the coupling method for heat and structure was applied during the simulation. The emphasis was laid on parametric factors of axial compression ratio, the form and the degree of the initial damages, as well as the confined condition at the ends of the columns. The numerical results showed that the fire-resistance temperature will lower as increasing of the axial compression ratio, the form and the degree of the initial damages and it will be also affected by the restraint conditions at the ends of the columns. The critical stress formula with initial bending damage under elevated temperature was set up under flexural small deformation condition, then the stability coefficient was determined and the method for evaluating the limit temperature of the column was put forward. The theoretical result was also compared with that of the finite element method (FEM). The results both showed that the stability capacity for the damaged columns was dramatically reduced as increasing the temperature and the initial damage level.

Disease spread across multiple scales in a spatial hierarchy: effect of host spatial structure and of inoculum quantity and distribution.

PubMed

Gosme, Marie; Lucas, Philippe

2009-07-01

Spatial patterns of both the host and the disease influence disease spread and crop losses. Therefore, the manipulation of these patterns might help improve control strategies. Considering disease spread across multiple scales in a spatial hierarchy allows one to capture important features of epidemics developing in space without using explicitly spatialized variables. Thus, if the system under study is composed of roots, plants, and planting hills, the effect of host spatial pattern can be studied by varying the number of plants per planting hill. A simulation model based on hierarchy theory was used to simulate the effects of large versus small planting hills, low versus high level of initial infections, and aggregated versus uniform distribution of initial infections. The results showed that aggregating the initially infected plants always resulted in slower epidemics than spreading out the initial infections uniformly. Simulation results also showed that, in most cases, disease epidemics were slower in the case of large host aggregates (100 plants/hill) than with smaller aggregates (25 plants/hill), except when the initially infected plants were both numerous and spread out uniformly. The optimal strategy for disease control depends on several factors, including initial conditions. More importantly, the model offers a framework to account for the interplay between the spatial characteristics of the system, rates of infection, and aggregation of the disease.

The Impact of Family Migration and Family Life Cycle on the Employment Status of Married, College-Educated Women.

ERIC Educational Resources Information Center

Yu, Lucy C.; And Others

1993-01-01

Data from 204 female faculty or faculty wives show that family life cycle (number and ages of children) and family migration significantly affect wives' employment status. Only extremely highly educated women initiate family relocation. (SK)

Oriented graphite layer formation in Ti/C and TiC/C multilayers deposited by high current pulsed cathodic arc

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

Persson, P. O. A.; Ryves, L.; Tucker, M. D.

2008-10-01

Ti/C and TiC/C multilayers with periods ranging from 2 to 18 nm were grown by filtered high current pulsed cathodic arc. The growth was monitored in situ by ellipsometry and cantilever stress measurements. The ellipsometry results reveal that the optical properties of the carbon vary as a function of thickness. Correspondingly, the stress in each carbon layer as measured in situ exhibits two well defined values: initially the stress is low and then takes on a higher value for the remainder of the layer. Transmission electron microscopy shows that the initial growth of carbon on Ti or TiC layer ismore » oriented with graphitic basal planes aligned parallel to the interface. After 2-4 nm of growth, the graphitic structure transforms to amorphous carbon. Electron energy loss spectroscopy shows that the carbon layer simultaneously undergoes a transition from sp{sup 2} rich to sp{sup 3} rich material.« less

Synthesis, Amphiphilic Property and Thermal Stability of Novel Main-chain Poly(o-carborane-benzoxazines)

NASA Astrophysics Data System (ADS)

Yang, Xiaoxue; Han, Guo; Yang, Zhen; Zhang, Xiaoa; Jiang, Shengling; Lyu, Yafei

2017-10-01

Five poly(o-carborane-benzoxazines) were synthesized via Mannich reaction of o-carborane bisphenol, paraformaldehyde, and diamine, and their structures were well characterized. Light transmission and 1H NMR in D2O confirmed that poly(o-carborane-benzoxazines) with PEG segments showed excellent water solubility and amphiphilic property. TGA analyses were conducted under nitrogen and air, and the results showed that the polymers own high initial decomposition temperatures owing to the shielding effect of carborane moiety on its adjacent aromatic structures. Besides, poly(o-carborane-benzoxazines) own high char yield at elevated temperatures, for the boron atom could combine with oxygen from the polymer structure or/and the air and be oxidized to form boron oxide, and thus the polymer weight is retained to a large extent. PEG segments had an adverse effect on the initial decomposition and char yield, and thus their concentration should be adjusted to control the polymer’s thermal stability.

Statistical analysis and isotherm study of uranium biosorption by Padina sp. algae biomass.

PubMed

Khani, Mohammad Hassan

2011-06-01

The application of response surface methodology is presented for optimizing the removal of U ions from aqueous solutions using Padina sp., a brown marine algal biomass. Box-Wilson central composite design was employed to assess individual and interactive effects of the four main parameters (pH and initial uranium concentration in solutions, contact time and temperature) on uranium uptake. Response surface analysis showed that the data were adequately fitted to second-order polynomial model. Analysis of variance showed a high coefficient of determination value (R (2)=0.9746) and satisfactory second-order regression model was derived. The optimum pH and initial uranium concentration in solutions, contact time and temperature were found to be 4.07, 778.48 mg/l, 74.31 min, and 37.47°C, respectively. Maximized uranium uptake was predicted and experimentally validated. The equilibrium data for biosorption of U onto the Padina sp. were well represented by the Langmuir isotherm, giving maximum monolayer adsorption capacity as high as 376.73 mg/g.

Fulminate Hepatic Failure as an Initial Presentation of Non-Hodgkin Lymphoma: A Case Report

PubMed Central

Ahmadi, Bizhan; Shafieipour, Sara; Akhavan Rezayat, Kambiz

2014-01-01

Viral hepatitis and toxins comprise most common causes of fulminate hepatic failure that are often diagnosed with standard laboratory tests. Herein we discuss a rare, difficult to diagnosis etiology of acute liver failure (ALF). A 62-year-old man presented with a two-week history of fever and fatigue. At four days before admission he became lethargic. His past medical and drug histories were unremarkable. Physical examination revealed generalized jaundice, fever and loss of consciousness. Laboratory tests showed elevated liver transaminases with direct hyper-bilirubinemia. Abdominal ultrasonography and CT scan showed hepatosplenomegaly and para-aortic abdominal lymphadenopathy. A further work-up included liver biopsy. The histopathology and imunohistochemistry was compatible with diffuse large B-cell lymphoma. He underwent high dose glucocorticoid therapy but his condition deteriorated rapidly and he died eight days after admission. ALF as an initial manifestation of malignant hepatic infiltration is extremely rare yet should be considered in all patients with unknown hepatic failure that are highly suspicious for malignant neoplasm. PMID:24872870

THE PRE-PENUMBRAL MAGNETIC CANOPY IN THE SOLAR ATMOSPHERE

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

MacTaggart, David; Guglielmino, Salvo L.; Zuccarello, Francesca

2016-11-01

Penumbrae are the manifestation of magnetoconvection in highly inclined (to the vertical direction) magnetic field. The penumbra of a sunspot tends to form, initially, along the arc of the umbra antipodal to the main region of flux emergence. The question of how highly inclined magnetic field can concentrate along the antipodal curves of umbrae, at least initially, remains to be answered. Previous observational studies have suggested the existence of some form of overlying magnetic canopy that acts as the progenitor for penumbrae. We propose that such overlying magnetic canopies are a consequence of how the magnetic field emerges into themore » atmosphere and are, therefore, part of the emerging region. We show, through simulations of twisted flux tube emergence, that canopies of highly inclined magnetic field form preferentially at the required locations above the photosphere.« less

Work and nonwork outcomes of workplace incivility: Does family support help?

PubMed

Lim, Sandy; Lee, Alexia

2011-01-01

This study extended incivility research beyond the confines of the workplace by exploring the relationships between incivility, work-to-family conflict and family support. Data collected from 180 employees from various organizations in Singapore showed that incivility is not a rare phenomenon in Asian cultures. Employees experienced more incivility from superiors than coworkers or subordinates, and these experiences were related to different outcomes. Coworker-initiated incivility was associated with decreased coworker satisfaction, increased perceptions of unfair treatment, and increased depression. On the other hand, superior-initiated incivility was associated with decreased supervisor satisfaction and increased work-to-family conflict. Results also revealed that employees with high family support showed stronger relationships between workplace incivility and negative outcomes, compared with employees with low family support.

Structure of initial crystals formed during human amelogenesis

NASA Astrophysics Data System (ADS)

Cuisinier, F. J. G.; Voegel, J. C.; Yacaman, J.; Frank, R. M.

1992-02-01

X-ray diffraction analysis revealed only the existence of carbonated hydroxyapatite (c.HA) during amelogenesis, whereas conventional transmission electron microscopy investigations showed that developing enamel crystals have a ribbon-like habit. The described compositional changes could be an indication for the presence of minerals different from c.HA. However, the absence of identification of such a mineral shows the need of studies by high resolution electron microscopy (HREM) of initial formed human enamel crystals. We demonstrate the existence of two crystal families involved in the early stages of biomineralization: (a) nanometer-size particles which appeared as a precursor phase; (b) ribbon-like crystals, with a structure closely related to c.HA, which by a progressive thickening process tend to attain the mature enamel crystal habit.

Effect of heat wave at the initial stage in spark plasma sintering.

PubMed

Zhang, Long; Zhang, Xiaomin; Chu, Zhongxiang; Peng, Song; Yan, Zimin; Liang, Yuan

2016-01-01

Thermal effects are important considerations at the initial stage in spark plasma sintering of non-conductive Al2O3 powders. The generalized thermo-elastic theory is introduced to describe the influence of the heat transport and thermal focusing caused by thermal wave propagation within a constrained space and transient time. Simulations show that low sintering temperature can realize high local temperature because of the superposition effect of heat waves. Thus, vacancy concentration differences between the sink and the cross section of the particles increase relative to that observed during pressure-less and hot-pressure sintering. Results show that vacancy concentration differences are significantly improved during spark plasma sintering, thereby decreasing the time required for sintering.

Analysis of the acceleration profile according to initial speed and positional role in elite professional male soccer players.

PubMed

de Hoyo, Moisés; Sañudo, Borja; Suárez-Arrones, Luis; Carrasco, Luis; Joel, Tom; Domínguez-Cobo, Sergio; Núñez, Francisco J

2017-12-01

The aim of the current study was to analyse the acceleration profile in elite professional soccer players according to their initial speed but also considering players' position. Players' accelerations profiles were analysed using a relative acceleration profile according to the initial speed (S1, from 0 to 7 km/h; S2, from 7.1 to 14.3 km/h; and S3, ≥14.4 km/h) and the maximum acceleration. Within-group analyses showed that Center Backs (CB) performed more high intensity accelerations (likely) when they started in S1 than S2 (ES: 0.50). Strikers (S) and Wide Midfielders (W-MD) achieved more accelerations (likely to almost certain) starting in S3 than S1 (ES: 0.80 and 0.59, respectively) and S2 (ES: 0.67 and 1.09, respectively). Full Backs (FB) completed more accelerations (almost certain) starting in S1 and S3 than S2 (ES: 1.39 and 1.36, respectively). Finally, Midfielders (MD) executed a greater number of high intensity accelerations (likely to almost certain) when they started in S1 than S2 (ES: 0.83) and S3 (ES: 0.66), and in S3 than S2 (ES: 4.72). Between-group analyses showed that S, W-MD, and FB performed a greater total number of high intensity accelerations (very likely to almost certain) than CB (ES: 1.94, 1.57, and 1.51, respectively) and MD (ES: 1.23, 0.92; and 0.81, respectively). Furthermore, MD performed substantially greater total number of high intensity accelerations (likely) than CB (ES: 0.56). Results suggest that CB achieved more high-intensity accelerations starting in low and moderate speed, S and W-MD in high speed, and FB combined low and high speed.

Simultaneous effect of initial moisture content and airflow rate on biodrying of sewage sludge.

PubMed

Huiliñir, Cesar; Villegas, Manuel

2015-10-01

The simultaneous effect of initial moisture content (initial Mc) and air-flow rate (AFR) on biodrying performance was evaluated. For the study, a 3(2) factorial design, whose factors were AFR (1, 2 and 3 L/min kg(TS)) and initial Mc (59, 68 and 78% w.b.), was used. Using energy and water mass balance the main routes of water removal, energy use and efficiencies were determined. The results show that initial Mc has a stronger effect on the biodrying than the AFR, affecting the air outlet temperature and improving the water removal, with higher maximum temperatures obtained around 68% and the lowest maximum matrix temperature obtained at initial Mc = 78%.Through the water mass balance it was found that the main mechanism for water removal was the aeration, with higher water removal at intermediate initial Mc (68%) and high AFR (3 L/min kg(TS)). The energy balance indicated that bioreaction is the main energy source for water evaporation, with higher energy produced at intermediate initial Mc (68%). Finally, it was found that low values of initial Mc (59%) improve biodrying efficiency. Copyright © 2015 Elsevier Ltd. All rights reserved.

Large eddy simulation of the low temperature ignition and combustion processes on spray flame with the linear eddy model

NASA Astrophysics Data System (ADS)

Wei, Haiqiao; Zhao, Wanhui; Zhou, Lei; Chen, Ceyuan; Shu, Gequn

2018-03-01

Large eddy simulation coupled with the linear eddy model (LEM) is employed for the simulation of n-heptane spray flames to investigate the low temperature ignition and combustion process in a constant-volume combustion vessel under diesel-engine relevant conditions. Parametric studies are performed to give a comprehensive understanding of the ignition processes. The non-reacting case is firstly carried out to validate the present model by comparing the predicted results with the experimental data from the Engine Combustion Network (ECN). Good agreements are observed in terms of liquid and vapour penetration length, as well as the mixture fraction distributions at different times and different axial locations. For the reacting cases, the flame index was introduced to distinguish between the premixed and non-premixed combustion. A reaction region (RR) parameter is used to investigate the ignition and combustion characteristics, and to distinguish the different combustion stages. Results show that the two-stage combustion process can be identified in spray flames, and different ignition positions in the mixture fraction versus RR space are well described at low and high initial ambient temperatures. At an initial condition of 850 K, the first-stage ignition is initiated at the fuel-lean region, followed by the reactions in fuel-rich regions. Then high-temperature reaction occurs mainly at the places with mixture concentration around stoichiometric mixture fraction. While at an initial temperature of 1000 K, the first-stage ignition occurs at the fuel-rich region first, then it moves towards fuel-richer region. Afterwards, the high-temperature reactions move back to the stoichiometric mixture fraction region. For all of the initial temperatures considered, high-temperature ignition kernels are initiated at the regions richer than stoichiometric mixture fraction. By increasing the initial ambient temperature, the high-temperature ignition kernels move towards richer mixture regions. And after the spray flames gets quasi-steady, most heat is released at the stoichiometric mixture fraction regions. In addition, combustion mode analysis based on key intermediate species illustrates three-mode combustion processes in diesel spray flames.

Variable Selection for Support Vector Machines in Moderately High Dimensions

PubMed Central

Zhang, Xiang; Wu, Yichao; Wang, Lan; Li, Runze

2015-01-01

Summary The support vector machine (SVM) is a powerful binary classification tool with high accuracy and great flexibility. It has achieved great success, but its performance can be seriously impaired if many redundant covariates are included. Some efforts have been devoted to studying variable selection for SVMs, but asymptotic properties, such as variable selection consistency, are largely unknown when the number of predictors diverges to infinity. In this work, we establish a unified theory for a general class of nonconvex penalized SVMs. We first prove that in ultra-high dimensions, there exists one local minimizer to the objective function of nonconvex penalized SVMs possessing the desired oracle property. We further address the problem of nonunique local minimizers by showing that the local linear approximation algorithm is guaranteed to converge to the oracle estimator even in the ultra-high dimensional setting if an appropriate initial estimator is available. This condition on initial estimator is verified to be automatically valid as long as the dimensions are moderately high. Numerical examples provide supportive evidence. PMID:26778916

Diverged composition and regulation of the Trypanosoma brucei origin recognition complex that mediates DNA replication initiation

PubMed Central

Marques, Catarina A.; Tiengwe, Calvin; Lemgruber, Leandro; Damasceno, Jeziel D.; Scott, Alan; Paape, Daniel; Marcello, Lucio; McCulloch, Richard

2016-01-01

Abstract Initiation of DNA replication depends upon recognition of genomic sites, termed origins, by AAA+ ATPases. In prokaryotes a single factor binds each origin, whereas in eukaryotes this role is played by a six-protein origin recognition complex (ORC). Why eukaryotes evolved a multisubunit initiator, and the roles of each component, remains unclear. In Trypanosoma brucei, an ancient unicellular eukaryote, only one ORC-related initiator, TbORC1/CDC6, has been identified by sequence homology. Here we show that three TbORC1/CDC6-interacting factors also act in T. brucei nuclear DNA replication and demonstrate that TbORC1/CDC6 interacts in a high molecular complex in which a diverged Orc4 homologue and one replicative helicase subunit can also be found. Analysing the subcellular localization of four TbORC1/CDC6-interacting factors during the cell cycle reveals that one factor, TbORC1B, is not a static constituent of ORC but displays S-phase restricted nuclear localization and expression, suggesting it positively regulates replication. This work shows that ORC architecture and regulation are diverged features of DNA replication initiation in T. brucei, providing new insight into this key stage of eukaryotic genome copying. PMID:26951375

Fine characterization rock thermal damage by acoustic emission technique

NASA Astrophysics Data System (ADS)

Kong, Biao; Li, Zenghua; Wang, Enyuan

2018-02-01

This paper examines the differences in the thermal mechanical properties and acoustic emission (AE) characteristics during the deformation and fracture of rock under the action of continuous heating and after high-temperature treatment. Using AE 3D positioning technology, the development and evolution of the internal thermal cracks and the time domain of AE signals in rock were analyzed. High-temperature treatment causes thermal damage to rock. Under the action of continuous heating, the phase characteristics of AE time series correspond to the five stages of rock thermal deformation and fracture, respectively: the micro-defect development stage, the threshold interval of rock micro-cracks, the crack initiation stage, the crack propagation stage, and the crack multistage propagation evolution. When the initial crack propagates, the crack initiation of the rock causes the AE signal to produce a sudden mutation change. Mechanical fraction characteristics during rock uniaxial compression after temperature treatment indicated that the decrease rate of the rock compressive strength, wave velocity, and elastic modulus are relatively large during uniaxial compression tests after high-temperature treatment. During the deformation and fracture of rock under loading, there is faster growth of AE counts and AE events, indicating an increase in the speed of rock deformation and fracture under loading. AE counts show obvious changes during the latter loading stages, whereas AE events show obvious changes during the loading process. The results obtained are valuable for rock thermal stability detection and evaluation in actual underground engineering.

Towards a comparable carbon footprint for local initiatives: The FP7 project TESS

NASA Astrophysics Data System (ADS)

Reusser, Dominik E.; Kropp, Jürgen P.

2014-05-01

TESS (Towards European Societal Sustainability -- www.tess-transition.eu) is a three-year, European-wide research project. It aims to reach an understanding of the potential for community-led initiatives to help deliver a truly sustainable, low-carbon future. Transitions to low-carbon societies take place at multiple and complementary scales. Transition processes are highly dependent on the innovative potential of community-based initiatives and their articulation with appropriate institutional architecture. Community-based initiatives are potentially more adaptable and less constrained by current structural circumstances than top-down policies and can give impetus to large-scale and technology driven changes. TESS will provide an understanding on the upscaling possibilities of such high-potential community-based initiatives by addressing two main questions: What is the impact of community-based initiatives in terms of carbon reduction potential and economic effect? What institutional structures (values, policies and mechanisms) support these initiatives in persisting beyond the initial phase and moving into an acceleration phase, spreading desired impacts? Answers will be provided through (1) a novel measuring, reporting and verification (MRV) framework for benchmarking community-based initiatives. This will enable quantifiable, comparable and standardised evaluation, and (2) the identification of success factors for the emergence, persistence and diffusion of promising initiatives, including online initiatives. We will identify these initiatives through case studies across regions and sectors and produce a systemic understanding of their impact on societal transitions towards sustainability. Our research will be integrated and transdisciplinary, with the unique opportunity to bring together social and natural scientists to foster a transition towards European societal sustainability. Our work will feed into and extend the Climate Adapt database to facilitate reconciliation of mitigation and adaptation and connect to Europe wide evaluation approaches such as the Common Monitoring and Evaluation Framework (CMEF) of the Rural Development Programmes. The poster will show the current state of the initiative selection process and of the method development.

The effect of family policies and public health initiatives on breastfeeding initiation among 18 high-income countries: a qualitative comparative analysis research design.

PubMed

Lubold, Amanda Marie

2017-01-01

The objective of this study is to examine the effects of macro-level factors - welfare state policies and public health initiatives - on breastfeeding initiation among eighteen high-income countries. This study utilizes fuzzy-set Qualitative Comparative Analysis methods to examine the combinations of conditions leading to both high and low national breastfeeding initiation rates among eighteen high-income countries. The most common pathway leading to high breastfeeding initiation is the combination of conditions including a high percentage of women in parliament, a low national cesarean section rate, and either low family spending, high rates of maternity leave, or high rates of women working part-time. The most common pathway leading to low breastfeeding initiation includes the necessary condition of low national adherence to the Baby-Friendly Hospital Initiative. This research suggests that there is a connection between broad level welfare state polices, public health initiatives, and breastfeeding initiation. Compliance with the WHO/UNICEF initiatives depends on welfare regime policies and overall support for women in both productive and reproductive labor.

Minimally displaced clavicle fracture after high-energy injury: are they likely to displace?

PubMed

Riehl, John T; Athans, Bill J; Munro, Mark W; Langford, Joshua R; Kupiszewski, Stanley J; Haidukewych, George J; Koval, Kenneth J

2014-06-01

Nondisplaced or minimally displaced clavicle fractures are often considered to be benign injuries. These fractures in the trauma patient population, however, may deserve closer follow-up than their low-energy counterparts. We sought to determine the initial assessment performed on these patients and the rate of subsequent fracture displacement in patients sustaining high-energy trauma when a supine chest radiograph on initial trauma survey revealed a well-aligned clavicle fracture. We retrospectively reviewed the cases of trauma alert patients who sustained a midshaft clavicle fracture (AO/OTA type 15-B) with less than 100% displacement treated at a single level 1 trauma centre between 2005 and 2010. We compared fracture displacement on initial supine chest radiographs and follow-up radiographs. Orthopedic consultation and the type of imaging studies obtained were also recorded. Ninety-five patients with clavicle fractures met the inclusion criteria. On follow-up, 57 (60.0%) had displacement of 100% or more of the shaft width. Most patients (63.2%) in our study had an orthopedic consultation during their hospital admission, and 27.4% had clavicle radiographs taken on the day of admission. Clavicle fractures in patients with a high-energy mechanism of injury are prone to fracture displacement, even when initial supine chest radiographs show nondisplacement. We recommend clavicle films as part of the initial evaluation for all patients with clavicle fractures and early follow-up within the first 2 weeks of injury.

Minimally displaced clavicle fracture after high-energy injury: Are they likely to displace?

PubMed Central

Riehl, John T.; Athans, Bill J.; Munro, Mark W.; Langford, Joshua R.; Kupiszewski, Stanley J.; Haidukewych, George J.; Koval, Kenneth J.

2014-01-01

Background Nondisplaced or minimally displaced clavicle fractures are often considered to be benign injuries. These fractures in the trauma patient population, however, may deserve closer follow-up than their low-energy counterparts. We sought to determine the initial assessment performed on these patients and the rate of subsequent fracture displacement in patients sustaining high-energy trauma when a supine chest radiograph on initial trauma survey revealed a well-aligned clavicle fracture. Methods We retrospectively reviewed the cases of trauma alert patients who sustained a midshaft clavicle fracture (AO/OTA type 15-B) with less than 100% displacement treated at a single level 1 trauma centre between 2005 and 2010. We compared fracture displacement on initial supine chest radiographs and follow-up radiographs. Orthopedic consultation and the type of imaging studies obtained were also recorded. Results Ninety-five patients with clavicle fractures met the inclusion criteria. On follow-up, 57 (60.0%) had displacement of 100% or more of the shaft width. Most patients (63.2%) in our study had an orthopedic consultation during their hospital admission, and 27.4% had clavicle radiographs taken on the day of admission. Conclusion Clavicle fractures in patients with a high-energy mechanism of injury are prone to fracture displacement, even when initial supine chest radiographs show nondisplacement. We recommend clavicle films as part of the initial evaluation for all patients with clavicle fractures and early follow-up within the first 2 weeks of injury. PMID:24869608

Effects of defects on thermal decomposition of HMX via ReaxFF molecular dynamics simulations.

PubMed

Zhou, Ting-Ting; Huang, Feng-Lei

2011-01-20

Effects of molecular vacancies on the decomposition mechanisms and reaction dynamics of condensed-phase β-HMX at various temperatures were studied using ReaxFF molecular dynamics simulations. Results show that three primary initial decomposition mechanisms, namely, N-NO(2) bond dissociation, HONO elimination, and concerted ring fission, exist at both high and lower temperatures. The contribution of the three mechanisms to the initial decomposition of HMX is influenced by molecular vacancies, and the effects vary with temperature. At high temperature (2500 K), molecular vacancies remarkably promote N-N bond cleavage and concerted ring breaking but hinder HONO formation. N-N bond dissociation and HONO elimination are two primary competing reaction mechanisms, and the former is dominant in the initial decomposition. Concerted ring breaking of condensed-phase HMX is not favored at high temperature. At lower temperature (1500 K), the most preferential initial decomposition pathway is N-N bond dissociation followed by the formation of NO(3) (O migration), although all three mechanisms are promoted by molecular vacancies. The promotion effect on concerted ring breaking is considerable at lower temperature. Products resulting from concerted ring breaking appear in the defective system but not in the perfect crystal. The mechanism of HONO elimination is less important at lower temperature. We also estimated the reaction rate constant and activation barriers of initial decomposition with different vacancy concentrations. Molecular vacancies accelerate the decomposition of condensed-phase HMX by increasing the reaction rate constant and reducing activation barriers.

Multi-model assessment of the impact of soil moisture initialization on mid-latitude summer predictability

NASA Astrophysics Data System (ADS)

Ardilouze, Constantin; Batté, L.; Bunzel, F.; Decremer, D.; Déqué, M.; Doblas-Reyes, F. J.; Douville, H.; Fereday, D.; Guemas, V.; MacLachlan, C.; Müller, W.; Prodhomme, C.

2017-12-01

Land surface initial conditions have been recognized as a potential source of predictability in sub-seasonal to seasonal forecast systems, at least for near-surface air temperature prediction over the mid-latitude continents. Yet, few studies have systematically explored such an influence over a sufficient hindcast period and in a multi-model framework to produce a robust quantitative assessment. Here, a dedicated set of twin experiments has been carried out with boreal summer retrospective forecasts over the 1992-2010 period performed by five different global coupled ocean-atmosphere models. The impact of a realistic versus climatological soil moisture initialization is assessed in two regions with high potential previously identified as hotspots of land-atmosphere coupling, namely the North American Great Plains and South-Eastern Europe. Over the latter region, temperature predictions show a significant improvement, especially over the Balkans. Forecast systems better simulate the warmest summers if they follow pronounced dry initial anomalies. It is hypothesized that models manage to capture a positive feedback between high temperature and low soil moisture content prone to dominate over other processes during the warmest summers in this region. Over the Great Plains, however, improving the soil moisture initialization does not lead to any robust gain of forecast quality for near-surface temperature. It is suggested that models biases prevent the forecast systems from making the most of the improved initial conditions.

The Sooner, the Worse? Association between Earlier Age of Sexual Initiation and Worse Adolescent Health and Well-being Outcomes

PubMed Central

Osorio, Alfonso; Lopez-del Burgo, Cristina; Carlos, Silvia; de Irala, Jokin

2017-01-01

This cross-sectional study assesses the association between age of sexual initiation during adolescence and a selection of well-being outcomes regarding that first relationship. High-school adolescents from El Salvador (2,686) and from Peru (3,399) replied to a paper-pencil questionnaire. Those who were sexually initiated replied to several questions regarding their age at sexual initiation, condom use, satisfaction and reasons/circumstances for that sexual relationship. Approximately 19% of participants were sexually initiated (n = 1,179). After retaining participants with valid responses and with sexual initiation ages between 13 and 17, the final sample for this paper consisted of 996 sexually initiated participants (526 Salvadorians and 470 Peruvians). Multiple logistic regression analyses showed that those who initiated sex at earlier ages had worse outcomes compared to those who initiated at older ages. Specifically, they had lower odds of having used a condom, of having good memories of that experience and of having had that first relationship because they were in love. Conversely, they had higher odds of having had that first sexual relationship as a result of peer pressure (“Most of my friends already had sex”), because of partner pressure (“I was afraid to lose him/her,” “My partner told me he/she would leave me” or “I did not know how to say no to a person who insisted”), or as a consequence of different forms of impaired autonomy (“I was under the influence of alcohol or drugs” or “As a consequence of seeing sexual images”). Results show that sex at earlier ages is associated with worse adolescent health and well-being outcomes. PMID:28798715

Structural domains within the HIV-1 mRNA and the ribosomal protein S25 influence cap-independent translation initiation.

PubMed

Carvajal, Felipe; Vallejos, Maricarmen; Walters, Beth; Contreras, Nataly; Hertz, Marla I; Olivares, Eduardo; Cáceres, Carlos J; Pino, Karla; Letelier, Alejandro; Thompson, Sunnie R; López-Lastra, Marcelo

2016-07-01

The 5' leader of the HIV-1 genomic RNA is a multifunctional region that folds into secondary/tertiary structures that regulate multiple processes during viral replication including translation initiation. In this work, we examine the internal ribosome entry site (IRES) located in the 5' leader that drives translation initiation of the viral Gag protein under conditions that hinder cap-dependent translation initiation. We show that activity of the HIV-1 IRES relies on ribosomal protein S25 (eS25). Additionally, a mechanistic and mutational analysis revealed that the HIV-1 IRES is modular in nature and that once the 40S ribosomal subunit is recruited to the IRES, translation initiates without the need of ribosome scanning. These findings elucidate a mechanism of initiation by the HIV-1 IRES whereby a number of highly structured sites present within the HIV-1 5' leader leads to the recruitment of the 40S subunit directly at the site of initiation of protein synthesis. © 2016 Federation of European Biochemical Societies.

Structural domains within the HIV-1 mRNA and the ribosomal protein S25 influence cap-independent translation initiation

PubMed Central

Carvajal, Felipe; Vallejos, Maricarmen; Walters, Beth A.; Contreras, Nataly; Hertz, Marla I.; Olivares, Eduardo; Cáceres, C. Joaquín; Pino, Karla; Letelier, Alejandro; Thompson, Sunnie R.; López-Lastra, Marcelo

2016-01-01

The 5′leader of the HIV-1 genomic RNA is a multifunctional region that folds into secondary/tertiary structures that regulate multiple processes during viral replication including translation initiation. In this work we examine the internal ribosome entry site (IRES) located in the 5′leader that drives translation initiation of the viral Gag protein under conditions that hinder cap-dependent translation initiation. We show that activity of the HIV-1 IRES relies on ribosomal protein S25 (eS25). Additionally, a mechanistic and mutational analysis revealed that the HIV-1 IRES is modular in nature and that once the 40S ribosomal subunit is recruited to the IRES, translation initiates without the need of ribosome scanning. These findings elucidate a mechanism of initiation by the HIV-1 IRES whereby a number of highly structured sites present within the HIV-1 5′leader leads to the recruitment of the 40S subunit directly at the site of initiation of protein synthesis. PMID:27191820

Fatigue characteristics of carbon nanotube blocks under compression

NASA Astrophysics Data System (ADS)

Suhr, J.; Ci, L.; Victor, P.; Ajayan, P. M.

2008-03-01

In this paper we investigate the mechanical response from repeated high compressive strains on freestanding, long, vertically aligned multiwalled carbon nanotube membranes and show that the arrays of nanotubes under compression behave very similar to soft tissue and exhibit viscoelastic behavior. Under compressive cyclic loading, the mechanical response of nanotube blocks shows initial preconditioning and hysteresis characteristic of viscoeleastic materials. Furthermore, no fatigue failure is observed even at high strain amplitudes up to half million cycles. The outstanding fatigue life and extraordinary soft tissue-like mechanical behavior suggest that properly engineered carbon nanotube structures could mimic artificial muscles.

The effects of primary reward on the I.Q. performance of grade-school children as a function of initial I.Q. level1

PubMed Central

Clingman, Joy; Fowler, Robert L.

1976-01-01

The effect of candy reward on I.Q. scores was investigated in 72 first- and second-grade children. All subjects were administered Form A of the Peabody Picture Vocabulary Test and, based upon these scores, were divided into three blocks: low, middle, and high. From each block, subjects were randomly assigned to one of three conditions (contingent reward, noncontingent reward, or no reward) that were in effect during administration of Form B. Results showed that candy given contingent upon each correct response increased I.Q. scores for the initially low scoring subjects, but had no influence on the scores of middle and high scoring subjects. PMID:16795514

State orientation and memory load impair prospective memory performance in older compared to younger persons.

PubMed

Kaschel, Reiner; Kazén, Miguel; Kuhl, Julius

2017-07-01

A modified event-based paradigm of prospective memory was applied to investigate intention initiation in older and younger participants under high versus low memory load (subsequent episodic word recall vs. recognition). State versus action orientation, a personality dimension related to intention enactment, was also measured. State-oriented persons show a superiority effect for the storage of intentions in an explicit format but have a paradoxical deficit in their actual enactment. We predicted an interaction between aging, personality, and memory load, with longer intention-initiation latencies and higher omission rates for older state-oriented participants under high memory load. Results were consistent with predictions and are interpreted according to current personality and prospective memory models of aging.

The fatigue response of the aluminium-lithium alloy, 8090

NASA Technical Reports Server (NTRS)

Birt, M. J.; Beevers, C. J.

1989-01-01

The fatigue response of an Al-Li-Cu-Mg-Zr (8090) alloy has been studied at room temperature. The initiation and growth of small and long cracks has been examined at R = 0.1 and at a frequency of 100 Hz. Initiation was observed to occur dominantly at sub-grain boundaries. The growth of the small cracks was crystallographic in character and exhibited little evidence of retardation or arrest at the grain boundaries. The long crack data showed the alloy to have a high resistance to fatigue crack growth with underaging providing the optimum heat treatment for fatigue crack growth resistance. In general, this can be attributed to high levels of crack closure which resulted from the presence of extensive microstructurally related asperities.

Overflow of a dipolar exciton trap at high magnetic fields

NASA Astrophysics Data System (ADS)

Dietl, Sebastian; Kowalik-Seidl, Katarzyna; Hammer, Lukas; Schuh, Dieter; Wegscheider, Werner; Holleitner, Alexander; Wurstbauer, Ursula

We study the photoluminescence of trapped dipolar excitons (IX) in coupled double GaAs quantum wells at low temperatures and high magnetic fields. A voltage-tunable electrode geometry controls the strength of the quantum confined Stark effect and defines the lateral trapping potential. Furthermore, it enhances the IX lifetime, enabling them to cool down to lattice temperature. We show that a magnetic field in Faraday configuration effectively prevents the escape of unbound photogenerated charge carriers from the trap area, thus increasing the density of dipolar excitons. For large magnetic fields, we observe an overflow of the IX trap and an effectively suppressed quantum confined Stark effect. We acknowledge financial support by the German Excellence Initiative via the Nanosystems Initiative Munich (NIM).

Initial Results From The Chandra High Energy Transmission Grating Spectrometer

NASA Technical Reports Server (NTRS)

Canizares, C. R.; Davis, D. S.; Dewey, D.; Flanagan, K. A.; Houck, J.; Huenemoerder, D. P.; Marshall, H. L.; Schattenburg, M. L.; Schulz, N. S.; Wise, M.

2000-01-01

The High Energy Transmission Grating Spectrometer (HETGS) on the Chandra X-ray Observatory provides spectral resolving powers of 200-1000 over the range 0.4-8.0 keV (1.5-30 A) with effective area of 2-200 square centimeters. Initial observations during the activation and calibration phases of the mission show that the HETGS is performing as predicted prior to Chandra launch. The talk presented very preliminary results that illustrate the power of the HETGS for performing detailed studies of a wide range of celestial sources, including plasma diagnostics. This written version gives a brief summary of that talk with examples of preliminary spectra of Capella, the Crab pulsar, SS433 and the SNR E0102-72.

The Association of Individual and Regional Socioeconomic Status on Initial Peritonitis and Outcomes in Peritoneal Dialysis Patients: A Propensity Score-Matched Cohort Study.

PubMed

Wang, Qin; Hu, Ke-Jie; Ren, Ye-Ping; Dong, Jie; Han, Qing-Feng; Zhu, Tong-Ying; Chen, Jiang-Hua; Zhao, Hui-Ping; Chen, Meng-Hua; Xu, Rong; Wang, Yue; Hao, Chuan-Ming; Zhang, Xiao-Hui; Wang, Mei; Tian, Na; Wang, Hai-Yan

2016-01-01

♦ Research indicates that the socioeconomic status (SES) of individuals and the area where they live are related to initial peritonitis and outcomes in peritoneal dialysis (PD). We conducted a retrospective, multi-center cohort study in China to examine these associations. ♦ Data on 2,171 PD patients were collected from 7 centers, including baseline demographic, socioeconomic, and laboratory data. We explored the potential risk factors for initial peritonitis and outcomes using univariate Cox regression and unadjusted binary logistic regression. Then, we used propensity score matching to balance statistically significant risk factors for initial peritonitis and outcomes, and Kaplan-Meier survival analysis to compare differences in peritonitis-free rates between different groups of participants after matching. ♦ A total of 563 (25.9%) initial episodes of peritonitis occurred during the study period. The Kaplan-Meier peritonitis-free rate curve showed high-income patients had a significantly lower risk than low-income patients (p = 0.007) after matching for age, hemoglobin, albumin, and regional SES and PD center. The risk of treatment failure was significantly lower in the high-income than the low-income group after matching for the organism causing peritonitis and PD center: odds ratio (OR) = 0.27 (0.09 - 0.80, p = 0.018). Regional SES and education were not associated with initial peritonitis and outcomes. ♦ Our study demonstrates low individual income is a risk factor for the initial onset of peritonitis and treatment failure after initial peritonitis. Copyright © 2016 International Society for Peritoneal Dialysis.

Racing a Comet.

ERIC Educational Resources Information Center

Brearton, Mary Ann; Shuttleworth, Susan

1999-01-01

Project 2061 is a nationwide education-reform initiative that is in the forefront of the standards movement in science, mathematics, and technology education. It shows that high academic standards can support good professional development, and vice versa. This article describes the use of standards; explains the layers of standards (national,…

KINETICS OF CHROMATE REDUCTION DURING NAPHTHALENE DEGRADATION IN A MIXED CULTURE

EPA Science Inventory

A mixed culture of Bacillus sp. K1 and Sphingomonas paucimobilis EPA 505 was exposed to chromate and naphthalene. Batch experiments showed that chromate was reduced and naphthalene was degraded by the mixed culture. Chromate reduction occurred initially at a high rate followed by...

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

Hoth, Gregory W., E-mail: gregory.hoth@nist.gov; Pelle, Bruno; Riedl, Stefan

We demonstrate a two axis gyroscope by the use of light pulse atom interferometry with an expanding cloud of atoms in the regime where the cloud has expanded by 1.1–5 times its initial size during the interrogation. Rotations are measured by analyzing spatial fringe patterns in the atom population obtained by imaging the final cloud. The fringes arise from a correlation between an atom's initial velocity and its final position. This correlation is naturally created by the expansion of the cloud, but it also depends on the initial atomic distribution. We show that the frequency and contrast of these spatialmore » fringes depend on the details of the initial distribution and develop an analytical model to explain this dependence. We also discuss several challenges that must be overcome to realize a high-performance gyroscope with this technique.« less

Genetic Variation of North American Triatomines (Insecta: Hemiptera: Reduviidae): Initial Divergence between Species and Populations of Chagas Disease Vector

PubMed Central

Espinoza, Bertha; Martínez-Ibarra, Jose Alejandro; Villalobos, Guiehdani; De La Torre, Patricia; Laclette, Juan Pedro; Martínez-Hernández, Fernando

2013-01-01

The triatomines vectors of Trypanosoma cruzi are principal factors in acquiring Chagas disease. For this reason, increased knowledge of domestic transmission of T. cruzi and control of its insect vectors is necessary. To contribute to genetic knowledge of North America Triatominae species, we studied genetic variations and conducted phylogenetic analysis of different triatomines species of epidemiologic importance. Our analysis showed high genetic variations between different geographic populations of Triatoma mexicana, Meccus longipennis, M. mazzottii, M. picturatus, and T. dimidiata species, suggested initial divergence, hybridation, or classifications problems. In contrast, T. gerstaeckeri, T. bolivari, and M. pallidipennis populations showed few genetics variations. Analysis using cytochrome B and internal transcribed spacer 2 gene sequences indicated that T. bolivari is closely related to the Rubrofasciata complex and not to T. dimidiata. Triatoma brailovskyi and T. gerstaeckeri showed a close relationship with Dimidiata and Phyllosoma complexes. PMID:23249692

Massive, wide binaries as tracers of massive star formation

NASA Astrophysics Data System (ADS)

Griffiths, Daniel W.; Goodwin, Simon P.; Caballero-Nieves, Saida M.

2018-05-01

Massive stars can be found in wide (hundreds to thousands au) binaries with other massive stars. We use N-body simulations to show that any bound cluster should always have approximately one massive wide binary: one will probably form if none are present initially, and probably only one will survive if more than one is present initially. Therefore, any region that contains many massive wide binaries must have been composed of many individual subregions. Observations of Cyg OB2 show that the massive wide binary fraction is at least a half (38/74), which suggests that Cyg OB2 had at least 30 distinct massive star formation sites. This is further evidence that Cyg OB2 has always been a large, low-density association. That Cyg OB2 has a normal high-mass initial mass function (IMF) for its total mass suggests that however massive stars form, they `randomly sample' the IMF (as the massive stars did not `know' about each other).

Hydrodynamic collectivity in proton-proton collisions at 13 TeV

NASA Astrophysics Data System (ADS)

Zhao, Wenbin; Zhou, You; Xu, Hao-jie; Deng, Weitian; Song, Huichao

2018-05-01

In this paper, we investigate the hydrodynamic collectivity in proton-proton (p-p) collisions at 13 TeV, using iEBE-VISHNU hybrid model with HIJING initial conditions. With properly tuned parameters, our model simulations can remarkably describe all the measured 2-particle correlations, including integrated and differential elliptic flow coefficients for all charged and identified hadrons (KS0 , Λ). However, our model calculations show positive 4-particle cumulant c2 { 4 } in high multiplicity pp collisions, and can not reproduce the negative c2 { 4 } measured in experiment. Further investigations on the HIJING initial conditions show that the fluctuations of the second order anisotropy coefficient ε2 increases with the increase of its mean value, which leads to a similar trend of the flow fluctuations. For a simultaneous description of the 2- and 4- particle cumulants within the hydrodynamic framework, it is required to have significant improvements on initial condition for pp collisions, which is still lacking of knowledge at the moment.

Large deformation image classification using generalized locality-constrained linear coding.

PubMed

Zhang, Pei; Wee, Chong-Yaw; Niethammer, Marc; Shen, Dinggang; Yap, Pew-Thian

2013-01-01

Magnetic resonance (MR) imaging has been demonstrated to be very useful for clinical diagnosis of Alzheimer's disease (AD). A common approach to using MR images for AD detection is to spatially normalize the images by non-rigid image registration, and then perform statistical analysis on the resulting deformation fields. Due to the high nonlinearity of the deformation field, recent studies suggest to use initial momentum instead as it lies in a linear space and fully encodes the deformation field. In this paper we explore the use of initial momentum for image classification by focusing on the problem of AD detection. Experiments on the public ADNI dataset show that the initial momentum, together with a simple sparse coding technique-locality-constrained linear coding (LLC)--can achieve a classification accuracy that is comparable to or even better than the state of the art. We also show that the performance of LLC can be greatly improved by introducing proper weights to the codebook.

Energy broadening due to space-charge oscillations in high current electron beams. [SEPAC payload experiment on Spacelab 1

NASA Technical Reports Server (NTRS)

Katz, I.; Jongeward, G. A.; Parks, D. E.; Reasoner, D. L.; Purvis, C. K.

1986-01-01

During electron beam accelerator operation on Spacelab I, substantial fluxes of electrons were observed with energies greater than the initial beam energy. Numerical calculations are performed for the emission of an unneutralized, one-dimensional electron beam. These calculations show clearly that space charge oscillations, which are associated with the charge buildup on the emitter, strongly modify the beam and cause the returning beam particles to have a distribution of kinetic energies ranging from half to over twice the initial energy.

Collectivity in Small Collision Systems: An Initial-State Perspective

DOE PAGES

Schlichting, Sören; Tribedy, Prithwish

2016-01-01

Measurements of multiparticle correlations in the collisions of small systems such as p+p, p/d/ 3 He+A show striking similarity to the observations in heavy-ion collisions. A number of observables measured in the high-multiplicity events of these systems resemble features that are attributed to collectivity driven by hydrodynamics. However, alternative explanations based on initial-state dynamics are able to describe many characteristic features of these measurements. In this brief review, we highlight some of the recent developments and outstanding issues in this direction.

Improve your marketing effectiveness and net income through better prospecting.

PubMed

Gombeski, William R; Kantor, David; Bendycki, Nadine A; Wack, Jeff

2002-01-01

Prospecting is the process of finding customers who are ready to buy and can generate high net income for an organization. Leads for prospects come from three categories of sources: (1) organization-initiated; (2) acquired leads; and (3) marketing activity-initiated leads. Findings from a study of academic medical organizations showed a modest use of effective prospecting by hospitals surveyed and that there are opportunities to increase database marketing efforts. The data suggests that prospecting and its companion concept of qualifying are not fully integrated into many healthcare organization's marketing strategies and tactics.

Magnetohydrodynamic modelling of exploding foil initiators

NASA Astrophysics Data System (ADS)

Neal, William

2015-06-01

Magnetohydrodynamic (MHD) codes are currently being developed, and used, to predict the behaviour of electrically-driven flyer-plates. These codes are of particular interest to the design of exploding foil initiator (EFI) detonators but there is a distinct lack of comparison with high-fidelity experimental data. This study aims to compare a MHD code with a collection of temporally and spatially resolved diagnostics including PDV, dual-axis imaging and streak imaging. The results show the code's excellent representation of the flyer-plate launch and highlight features within the experiment that the model fails to capture.

Methane in Pluto's Atmosphere

NASA Astrophysics Data System (ADS)

Roe, Henry G.

2006-09-01

The abundance of methane in Pluto's atmosphere has not been remeasured since its initial detection in 1992 by Young et al. (1997). As Pluto recedes from the Sun its atmosphere should eventually collapse and freeze out on the surface, but recent occultation observations (Elliot et al. 2003) show an expansion of the atmosphere rather than contraction. New measurements of Pluto's atmospheric methane abundance are warranted. We obtained high resolution (R=25000) near-infrared spectra of Pluto in July 2006 with NIRSPEC at the W.M. Keck II telescope and will report our initial analysis and results.

Evolution of Fitness in Experimental Populations of Vesicular Stomatitis Virus

PubMed Central

Elena, S. F.; Gonzalez-Candelas, F.; Novella, I. S.; Duarte, E. A.; Clarke, D. K.; Domingo, E.; Holland, J. J.; Moya, A.

1996-01-01

The evolution of fitness in experimental clonal populations of vesicular stomatitis virus (VSV) has been compared under different genetic (fitness of initial clone) and demographic (population dynamics) regimes. In spite of the high genetic heterogeneity among replicates within experiments, there is a clear effect of population dynamics on the evolution of fitness. Those populations that went through strong periodic bottlenecks showed a decreased fitness in competition experiments with wild type. Conversely, mutant populations that were transferred under the dynamics of continuous population expansions increased their fitness when compared with the same wild type. The magnitude of the observed effect depended on the fitness of the original viral clone. Thus, high fitness clones showed a larger reduction in fitness than low fitness clones under dynamics with included periodic bottleneck. In contrast, the gain in fitness was larger the lower the initial fitness of the viral clone. The quantitative genetic analysis of the trait ``fitness'' in the resulting populations shows that genetic variation for the trait is positively correlated with the magnitude of the change in the same trait. The results are interpreted in terms of the operation of MULLER's ratchet and genetic drift as opposed to the appearance of beneficial mutations. PMID:8849878

Investigation of Microstructure and Mechanical Properties of ECAP-Processed AM Series Magnesium Alloy

NASA Astrophysics Data System (ADS)

Gopi, K. R.; Nayaka, H. Shivananda; Sahu, Sandeep

2016-09-01

Magnesium alloy Mg-Al-Mn (AM70) was processed by equal channel angular pressing (ECAP) at 275 °C for up to 4 passes in order to produce ultrafine-grained microstructure and improve its mechanical properties. ECAP-processed samples were characterized for microstructural analysis using optical microscopy, scanning electron microscopy, and transmission electron microscopy. Microstructural analysis showed that, with an increase in the number of ECAP passes, grains refined and grain size reduced from an average of 45 to 1 µm. Electron backscatter diffraction analysis showed the transition from low angle grain boundaries to high angle grain boundaries in ECAP 4 pass sample as compared to as-cast sample. The strength and hardness values an showed increasing trend for the initial 2 passes of ECAP processing and then started decreasing with further increase in the number of ECAP passes, even though the grain size continued to decrease in all the successive ECAP passes. However, the strength and hardness values still remained quite high when compared to the initial condition. This behavior was found to be correlated with texture modification in the material as a result of ECAP processing.

Successful Retreatment of Recurrent Intracranial Vertebral Artery Dissecting Aneurysms After Stent-Assisted Coil Embolization: A Self-Controlled Hemodynamic Analysis.

PubMed

Liu, Jian; Jing, Linkai; Zhang, Ying; Song, Ying; Wang, Yang; Li, Chuanhui; Wang, Yanmin; Mu, Shiqing; Paliwal, Nikhil; Meng, Hui; Linfante, Italo; Yang, Xinjian

2017-01-01

Intracranial vertebral artery dissecting aneurysms (VADAs) tend to recur despite successful stent-assisted coil embolization (SACE). Hemodynamics is useful in evaluating aneurysmal formation, growth, and rupture. Our aim was to evaluate the hemodynamic patterns of the recurrence of VADA. Between September 2009 and November 2013, all consecutive patients with recurrent VADAs after SACE in our institutions were enrolled. Recurrence was defined as recanalization and/or regrowth. We assessed the hemodynamic alterations in wall shear stress (WSS) and velocity after the initial SACE and subsequently after retreatment of the aneurysms that recurred. Five patients were included. After the initial treatment, 3 patients showed recanalization and 2 showed regrowth. In the 2 patients with regrowth, the 2 original aneurysms maintained complete occlusion; however, de novo aneurysm regrowth was confirmed near the previous site. Compared with 3 recanalized aneurysms, the completely occluded aneurysms showed high mean reductions in velocity and WSS after initial treatment (velocity, 77.6% vs. 57.7%; WSS, 74.2% vs. 52.4%); however, WSS remained high at the region near the previous lesion where the new aneurysm originated. After the second retreatment, there was no recurrence in any patient. Compared with the 3 aneurysms that recanalized, the 4 aneurysms that maintained complete occlusion showed higher reductions in velocity (62.9%) and WSS (71.1%). Our series indicated that hemodynamics might have an important role in recurrence of VADAs. After endovascular treatment, sufficient hemodynamic reduction in aneurysm dome, orifice, and parent vessel may be one of the key factors for preventing recurrence in VADAs. Copyright © 2016 Elsevier Inc. All rights reserved.

Stainless steel component with compressed fiber Bragg grating for high temperature sensing applications

NASA Astrophysics Data System (ADS)

Jinesh, Mathew; MacPherson, William N.; Hand, Duncan P.; Maier, Robert R. J.

2016-05-01

A smart metal component having the potential for high temperature strain sensing capability is reported. The stainless steel (SS316) structure is made by selective laser melting (SLM). A fiber Bragg grating (FBG) is embedded in to a 3D printed U-groove by high temperature brazing using a silver based alloy, achieving an axial FBG compression of 13 millistrain at room temperature. Initial results shows that the test component can be used for up to 700°C for sensing applications.

Observation of frequency up-conversion in the propagation of a high-power microwave pulse in a self-generated plasma

NASA Technical Reports Server (NTRS)

Kuo, S. P.; Zhang, Y. S.; Ren, A.

1990-01-01

A chamber experiment is conducted to study the propagation of a high-power microwave pulse. The results show that the pulse is experiencing frequency up-shift while ionizing the background air if the initial carrier frequency of the pulse is higher than the electron plasma frequency at the incident boundary. Such a frequency autoconversion process may lead to reflectionless propagation of a high-power microwave pulse through the atmosphere.

Chemical, morphological and functional properties of Brazilian jackfruit (Artocarpus heterophyllus L.) seeds starch.

PubMed

Madruga, Marta Suely; de Albuquerque, Fabíola Samara Medeiros; Silva, Izis Rafaela Alves; do Amaral, Deborah Silva; Magnani, Marciane; Queiroga Neto, Vicente

2014-01-15

Starches used in food industry are extracted from roots, tubers and cereals. Seeds of jackfruit are abundant and contain high amounts of starch. They are discarded during the fruit processing or consumption and can be an alternative source of starch. The starch was extract from the jackfruit seeds and characterised to chemical, morphological and functional properties. Soft and hard jackfruit seeds showed starch content of 92.8% and 94.5%, respectively. Starch granules showed round and bell shape and some irregular cuts on their surface with type-A crystallinity pattern, similar to cereals starches. The swelling power and solubility of jackfruit starch increased with increasing temperature, showing opaque pastes. The soft seeds starch showed initial and final gelatinisation temperature of 36°C and 56°C, respectively; while hard seeds starch presented initial gelatinisation at 40°C and final at 61°C. These results suggest that the Brazilian jackfruit seeds starches could be used in food products. Copyright © 2013 Elsevier Ltd. All rights reserved.

The Killer Fly Hunger Games: Target Size and Speed Predict Decision to Pursuit

PubMed Central

Wardill, Trevor J.; Knowles, Katie; Barlow, Laura; Tapia, Gervasio; Nordström, Karin; Olberg, Robert M.; Gonzalez-Bellido, Paloma T.

2015-01-01

Predatory animals have evolved to optimally detect their prey using exquisite sensory systems such as vision, olfaction and hearing. It may not be so surprising that vertebrates, with large central nervous systems, excel at predatory behaviors. More striking is the fact that many tiny insects, with their miniscule brains and scaled down nerve cords, are also ferocious, highly successful predators. For predation, it is important to determine whether a prey is suitable before initiating pursuit. This is paramount since pursuing a prey that is too large to capture, subdue or dispatch will generate a substantial metabolic cost (in the form of muscle output) without any chance of metabolic gain (in the form of food). In addition, during all pursuits, the predator breaks its potential camouflage and thus runs the risk of becoming prey itself. Many insects use their eyes to initially detect and subsequently pursue prey. Dragonflies, which are extremely efficient predators, therefore have huge eyes with relatively high spatial resolution that allow efficient prey size estimation before initiating pursuit. However, much smaller insects, such as killer flies, also visualize and successfully pursue prey. This is an impressive behavior since the small size of the killer fly naturally limits the neural capacity and also the spatial resolution provided by the compound eye. Despite this, we here show that killer flies efficiently pursue natural (Drosophila melanogaster) and artificial (beads) prey. The natural pursuits are initiated at a distance of 7.9 ± 2.9 cm, which we show is too far away to allow for distance estimation using binocular disparities. Moreover, we show that rather than estimating absolute prey size prior to launching the attack, as dragonflies do, killer flies attack with high probability when the ratio of the prey's subtended retinal velocity and retinal size is 0.37. We also show that killer flies will respond to a stimulus of an angular size that is smaller than that of the photoreceptor acceptance angle, and that the predatory response is strongly modulated by the metabolic state. Our data thus provide an exciting example of a loosely designed matched filter to Drosophila, but one which will still generate successful pursuits of other suitable prey. PMID:26398293

pH-adjustment strategy for volatile fatty acid production from high-strength wastewater for biological nutrient removal.

PubMed

Xie, Li; Liu, Hui; Chen, Yin-Guang; Zhou, Qi

2014-01-01

Volatile fatty acid (VFA) production from three types of high-strength organic wastewater (cassava thin stillage, starch wastewater and yellow-wine processing wastewater) were compared. The results showed that cassava thin stillage was the most suitable substrate, based on its high specific VFA production (0.68 g chemical oxygen demand (COD)/g initial soluble chemical oxygen demand (SCOD)) and yield (0.72 g COD/g SCOD) as well as low nutrient content in the substrate and fermented liquid. The acid fermented cassava thin stillage was evaluated and compared with sodium acetate in a sequencing batch reactor system. Total nitrogen removal efficiency was higher with fermented cassava thin stillage than with the sodium acetate. The effects of pH and a pH-adjustment strategy on VFA production and composition were determined using cassava thin stillage. At an initial pH range of 7-11, a relatively high VFA concentration of about 9 g COD/L was obtained. The specific VFA production (g COD/g initial SCOD) increased from 0.27 to 0.47 to 0.67 at pH 8 and from 0.26 to 0.68 to 0.81 at pH 9 (initial pH, interval pH, and constant pH adjustment, respectively). The dominant VFA species changed significantly with the increasing frequency of the pH adjustment. Further studies will examine the metabolic pathways responsible for VFA composition.

Identify High-Quality Protein Structural Models by Enhanced K-Means.

PubMed

Wu, Hongjie; Li, Haiou; Jiang, Min; Chen, Cheng; Lv, Qiang; Wu, Chuang

2017-01-01

Background. One critical issue in protein three-dimensional structure prediction using either ab initio or comparative modeling involves identification of high-quality protein structural models from generated decoys. Currently, clustering algorithms are widely used to identify near-native models; however, their performance is dependent upon different conformational decoys, and, for some algorithms, the accuracy declines when the decoy population increases. Results. Here, we proposed two enhanced K -means clustering algorithms capable of robustly identifying high-quality protein structural models. The first one employs the clustering algorithm SPICKER to determine the initial centroids for basic K -means clustering ( SK -means), whereas the other employs squared distance to optimize the initial centroids ( K -means++). Our results showed that SK -means and K -means++ were more robust as compared with SPICKER alone, detecting 33 (59%) and 42 (75%) of 56 targets, respectively, with template modeling scores better than or equal to those of SPICKER. Conclusions. We observed that the classic K -means algorithm showed a similar performance to that of SPICKER, which is a widely used algorithm for protein-structure identification. Both SK -means and K -means++ demonstrated substantial improvements relative to results from SPICKER and classical K -means.

Identify High-Quality Protein Structural Models by Enhanced K-Means

PubMed Central

Li, Haiou; Chen, Cheng; Lv, Qiang; Wu, Chuang

2017-01-01

Background. One critical issue in protein three-dimensional structure prediction using either ab initio or comparative modeling involves identification of high-quality protein structural models from generated decoys. Currently, clustering algorithms are widely used to identify near-native models; however, their performance is dependent upon different conformational decoys, and, for some algorithms, the accuracy declines when the decoy population increases. Results. Here, we proposed two enhanced K-means clustering algorithms capable of robustly identifying high-quality protein structural models. The first one employs the clustering algorithm SPICKER to determine the initial centroids for basic K-means clustering (SK-means), whereas the other employs squared distance to optimize the initial centroids (K-means++). Our results showed that SK-means and K-means++ were more robust as compared with SPICKER alone, detecting 33 (59%) and 42 (75%) of 56 targets, respectively, with template modeling scores better than or equal to those of SPICKER. Conclusions. We observed that the classic K-means algorithm showed a similar performance to that of SPICKER, which is a widely used algorithm for protein-structure identification. Both SK-means and K-means++ demonstrated substantial improvements relative to results from SPICKER and classical K-means. PMID:28421198

U-Th-Pb systematics in three Apollo 14 basalts and the problem of initial Pb in lunar rocks.

NASA Technical Reports Server (NTRS)

Tera, F.; Wasserburg, G. J.

1972-01-01

The isotopic composition of Pb and the elemental concentration of U, Th and Pb were measured on 'total' rock samples 14053, 14073 and 14310 and on mineral separates of 14310 and 14053. These are the first Pb-U isochrons obtained for lunar basalts and indicate a reasonable solution to the previous discrepancy between the different methods of 'absolute' age determination. The resulting U-Pb isochron ages are compatible with the Rb-Sr and K-Ar ages on the same rocks. However, it is not possible to establish a precise time of 'crystallization' from the Pb-U data because of the small angle of intersection between the linear arrays and the concordia curve. These data show that total rock model ages do not in general yield crystallization ages. The data on 14310 and 14053 show that these rocks were formed containing a highly radiogenic initial lead which accounts for the excessively high total rock model ages by the U-Th-Pb method. The data prove that at the time of extrusion of some basalts, unsupported lead with extremely high Pb-207/Pb-206 ratios was added to the lunar surface.

Revealing the Origin of Activity in Nitrogen-Doped Nanocarbons towards Electrocatalytic Reduction of Carbon Dioxide.

PubMed

Xu, Junyuan; Kan, Yuhe; Huang, Rui; Zhang, Bingsen; Wang, Bolun; Wu, Kuang-Hsu; Lin, Yangming; Sun, Xiaoyan; Li, Qingfeng; Centi, Gabriele; Su, Dangsheng

2016-05-23

Carbon nanotubes (CNTs) are functionalized with nitrogen atoms for reduction of carbon dioxide (CO2 ). The investigation explores the origin of the catalyst's activity and the role of nitrogen chemical states therein. The catalysts show excellent performances, with about 90 % current efficiency for CO formation and stability over 60 hours. The Tafel analyses and density functional theory calculations suggest that the reduction of CO2 proceeds through an initial rate-determining transfer of one electron to CO2 , which leads to the formation of carbon dioxide radical anion (CO2 (.-) ). The initial reduction barrier is too high on pristine CNTs, resulting in a very high overpotentials at which the hydrogen evolution reaction dominates over CO2 reduction. The doped nitrogen atoms stabilize the radical anion, thereby lowering the initial reduction barrier and improving the intrinsic activity. The most efficient nitrogen chemical state for this reaction is quaternary nitrogen, followed by pyridinic and pyrrolic nitrogen. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Twin robotic x-ray system for 2D radiographic and 3D cone-beam CT imaging

NASA Astrophysics Data System (ADS)

Fieselmann, Andreas; Steinbrener, Jan; Jerebko, Anna K.; Voigt, Johannes M.; Scholz, Rosemarie; Ritschl, Ludwig; Mertelmeier, Thomas

2016-03-01

In this work, we provide an initial characterization of a novel twin robotic X-ray system. This system is equipped with two motor-driven telescopic arms carrying X-ray tube and flat-panel detector, respectively. 2D radiographs and fluoroscopic image sequences can be obtained from different viewing angles. Projection data for 3D cone-beam CT reconstruction can be acquired during simultaneous movement of the arms along dedicated scanning trajectories. We provide an initial evaluation of the 3D image quality based on phantom scans and clinical images. Furthermore, initial evaluation of patient dose is conducted. The results show that the system delivers high image quality for a range of medical applications. In particular, high spatial resolution enables adequate visualization of bone structures. This system allows 3D X-ray scanning of patients in standing and weight-bearing position. It could enable new 2D/3D imaging workflows in musculoskeletal imaging and improve diagnosis of musculoskeletal disorders.

Time-invariant discord: high temperature limit and initial environmental correlations

NASA Astrophysics Data System (ADS)

Tabesh, F. T.; Karpat, G.; Maniscalco, S.; Salimi, S.; Khorashad, A. S.

2018-04-01

We present a thorough investigation of the phenomena of frozen and time-invariant quantum discord for two-qubit systems independently interacting with local reservoirs. Our work takes into account several significant effects present in decoherence models, which have not been yet explored in the context of time-invariant quantum discord, but which in fact must be typically considered in almost all realistic models. Firstly, we study the combined influence of dephasing, dissipation and heating reservoirs at finite temperature. Contrarily to previous claims in the literature, we show the existence of time-invariant discord at high temperature limit in the weak coupling regime and also examine the effect of thermal photons on the dynamical behavior of frozen discord. Secondly, we explore the consequences of having initial correlations between the dephasing reservoirs. We demonstrate in detail how the time-invariant discord is modified depending on the relevant system parameters such as the strength of the initial amount of entanglement between the reservoirs.

Lupus pneumonitis as the initial presentation of systemic lupus erythematosus: case series from a single institution.

PubMed

Wan, S A; Teh, C L; Jobli, A T

2016-11-01

Objective The aim of this study was to examine the clinical features, treatment and outcome of systemic lupus erythematosus (SLE) patients in our centre who presented with lupus pneumonitis as the initial manifestation. Methods We performed a retrospective review of all patients who presented with lupus pneumonitis during the initial SLE manifestation from March 2006 to March 2015. Results There were a total of five patients in our study who presented with fever and cough as the main clinical features. All patients had pulmonary infiltrates on chest radiographs. High-resolution computed tomography, which was performed in two patients, showed ground glass opacities with patchy consolidations bilaterally. All patients received high-dose steroids, 80% received intravenous cyclophosphamide and 60% received intravenous immunoglobulin. Two patients died from severe lupus pneumonitis within 2 weeks of admission despite treatment with ventilation, steroids, cyclophosphamide and intravenous immunoglobulin. Conclusions Acute lupus pneumonitis is an uncommon presentation of SLE. Mortality in this case series is 40%.

The Effects of Elaboration on the Strength of Doping-Related Attitudes: Resistance to Change and Behavioral Intentions.

PubMed

Horcajo, Javier; Luttrell, Andrew

2016-06-01

This experiment analyzed whether attitudes toward the legalization of several doping behaviors would resist change and predict behavioral intentions when they were initially formed through thoughtful (i.e., high elaboration) versus nonthoughtful (i.e., low elaboration) processes. Participants were randomly assigned first to a persuasive message either against or in favor of the legalization, which they read with relatively high or low degrees of deliberative thinking. Attitudes and intentions regarding legalization were assessed following that message. Next, each participant received a second message that was opposed to the first one, serving as an attack against the attitude that participants had just formed. Finally, attitudes were again assessed. As hypothesized, participants showed greater attitude-consistent intentions when they formed their initial attitudes through thoughtful (vs. nonthoughtful) consideration of the first message. Moreover, the second message resulted in greater resistance to attitude change when participants formed their initial attitudes through thoughtful (vs. nonthoughtful) processes.

High-pressure anaerobic digestion up to 100 bar: influence of initial pressure on production kinetics and specific methane yields.

PubMed

Merkle, Wolfgang; Baer, Katharina; Haag, Nicola Leonard; Zielonka, Simon; Ortloff, Felix; Graf, Frank; Lemmer, Andreas

2017-02-01

To ensure an efficient use of biogas produced by anaerobic digestion, in some cases it would be advisable to upgrade the biogenic gases and inject them into the transnational gas grids. To investigate biogas production under high-pressure conditions up to 100 bar, new pressure batch methane reactors were developed for preliminary lab-scale experiments with a mixture of grass and maize silage hydrolysate. During this investigation, the effects of different initial pressures (1, 50 and 100 bar) on pressure increase, gas production and the specific methane yield using nitrogen as inert gas were determined. Based on the experimental findings increasing initial pressures alter neither significantly, further pressure increases nor pressure increase rates. All supplied organic acids were degraded and no measurable inhibition of the microorganisms was observed. The results show that methane reactors can be operated at operating pressures up to 100 bar without any negative effects on methane production.

High-Mach number, laser-driven magnetized collisionless shocks

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

Schaeffer, Derek B.; Fox, W.; Haberberger, D.

Collisionless shocks are ubiquitous in space and astrophysical systems, and the class of supercritical shocks is of particular importance due to their role in accelerating particles to high energies. While these shocks have been traditionally studied by spacecraft and remote sensing observations, laboratory experiments can provide reproducible and multi-dimensional datasets that provide complementary understanding of the underlying microphysics. We present experiments undertaken on the OMEGA and OMEGA EP laser facilities that show the formation and evolution of high-Mach number collisionless shocks created through the interaction of a laser-driven magnetic piston and magnetized ambient plasma. Through time-resolved, 2-D imaging we observemore » large density and magnetic compressions that propagate at super-Alfvenic speeds and that occur over ion kinetic length scales. Electron density and temperature of the initial ambient plasma are characterized using optical Thomson scattering. Measurements of the piston laser-plasma are modeled with 2-D radiation-hydrodynamic simulations, which are used to initialize 2-D particle-in-cell simulations of the interaction between the piston and ambient plasmas. The numerical results show the formation of collisionless shocks, including the separate dynamics of the carbon and hydrogen ions that constitute the ambient plasma and their effect on the shock structure. Furthermore, the simulations also show the shock separating from the piston, which we observe in the data at late experimental times.« less

High-Mach number, laser-driven magnetized collisionless shocks

DOE PAGES

Schaeffer, Derek B.; Fox, W.; Haberberger, D.; ...

2017-12-08

Collisionless shocks are ubiquitous in space and astrophysical systems, and the class of supercritical shocks is of particular importance due to their role in accelerating particles to high energies. While these shocks have been traditionally studied by spacecraft and remote sensing observations, laboratory experiments can provide reproducible and multi-dimensional datasets that provide complementary understanding of the underlying microphysics. We present experiments undertaken on the OMEGA and OMEGA EP laser facilities that show the formation and evolution of high-Mach number collisionless shocks created through the interaction of a laser-driven magnetic piston and magnetized ambient plasma. Through time-resolved, 2-D imaging we observemore » large density and magnetic compressions that propagate at super-Alfvenic speeds and that occur over ion kinetic length scales. Electron density and temperature of the initial ambient plasma are characterized using optical Thomson scattering. Measurements of the piston laser-plasma are modeled with 2-D radiation-hydrodynamic simulations, which are used to initialize 2-D particle-in-cell simulations of the interaction between the piston and ambient plasmas. The numerical results show the formation of collisionless shocks, including the separate dynamics of the carbon and hydrogen ions that constitute the ambient plasma and their effect on the shock structure. Furthermore, the simulations also show the shock separating from the piston, which we observe in the data at late experimental times.« less

High-Mach number, laser-driven magnetized collisionless shocks

NASA Astrophysics Data System (ADS)

Schaeffer, D. B.; Fox, W.; Haberberger, D.; Fiksel, G.; Bhattacharjee, A.; Barnak, D. H.; Hu, S. X.; Germaschewski, K.; Follett, R. K.

2017-12-01

Collisionless shocks are ubiquitous in space and astrophysical systems, and the class of supercritical shocks is of particular importance due to their role in accelerating particles to high energies. While these shocks have been traditionally studied by spacecraft and remote sensing observations, laboratory experiments can provide reproducible and multi-dimensional datasets that provide a complementary understanding of the underlying microphysics. We present experiments undertaken on the OMEGA and OMEGA EP laser facilities that show the formation and evolution of high-Mach number collisionless shocks created through the interaction of a laser-driven magnetic piston and a magnetized ambient plasma. Through time-resolved, 2-D imaging, we observe large density and magnetic compressions that propagate at super-Alfvénic speeds and that occur over ion kinetic length scales. The electron density and temperature of the initial ambient plasma are characterized using optical Thomson scattering. Measurements of the piston laser-plasma are modeled with 2-D radiation-hydrodynamic simulations, which are used to initialize 2-D particle-in-cell simulations of the interaction between the piston and ambient plasmas. The numerical results show the formation of collisionless shocks, including the separate dynamics of the carbon and hydrogen ions that constitute the ambient plasma and their effect on the shock structure. The simulations also show the shock separating from the piston, which we observe in the data at late experimental times.

Recognition and killing of brain tumor stem-like initiating cells by CD8+ cytolytic T cells.

PubMed

Brown, Christine E; Starr, Renate; Martinez, Catalina; Aguilar, Brenda; D'Apuzzo, Massimo; Todorov, Ivan; Shih, Chu-Chih; Badie, Behnam; Hudecek, Michael; Riddell, Stanley R; Jensen, Michael C

2009-12-01

Solid tumors contain a subset of stem-like cells that are resistant to the cytotoxic effects of chemotherapy/radiotherapy, but their susceptibility to cytolytic T lymphocyte (CTL) effector mechanisms has not been well characterized. Using a panel of early-passage human brain tumor stem/initiating cell (BTSC) lines derived from high-grade gliomas, we show that BTSCs are subject to immunologic recognition and elimination by CD8(+) CTLs. Compared with serum-differentiated CD133(low) tumor cells and established glioma cell lines, BTSCs are equivalent with respect to expression levels of HLA class I and ICAM-1, similar in their ability to trigger degranulation and cytokine synthesis by antigen-specific CTLs, and equally susceptible to perforin-dependent CTL-mediated cytolysis. BTSCs are also competent in the processing and presentation of antigens as evidenced by the killing of these cells by CTL when antigen is endogenously expressed. Moreover, we show that CTLs can eliminate all BTSCs with tumor-initiating activity in an antigen-specific manner in vivo. Current models predict that curative therapies for many cancers will require the elimination of the stem/initiating population, and these studies lay the foundation for developing immunotherapeutic approaches to eradicate this tumor population.

Leuco-crystal-violet micelle gel dosimeters: Component effects on dose-rate dependence

NASA Astrophysics Data System (ADS)

Xie, J. C.; Katz, E. A. B.; Alexander, K. M.; Schreiner, L. J.; McAuley, K. B.

2017-05-01

Designed experiments were performed to produce empirical models for the dose sensitivity, initial absorbance, and dose-rate dependence respectively for leucocrystal violet (LCV) micelle gel dosimeters containing cetyltrimethylammonium bromide (CTAB) and 2,2,2-trichloroethanol (TCE). Previous gels of this type showed dose-rate dependent behaviour, producing an ˜18% increase in dose sensitivity between dose rates of 100 and 600 cGy min-1. Our models predict that the dose rate dependence can be reduced by increasing the concentration of TCE, CTAB and LCV. Increasing concentrations of LCV and CTAB produces a significant increase in dose sensitivity with a corresponding increase in initial absorbance. An optimization procedure was used to determine a nearly dose-rate independent gel which maintained high sensitivity and low initial absorbance. This gel which contains 33 mM CTAB, 1.25 mM LCV, and 96 mM TCE in 25 mM trichloroacetic acid and 4 wt% gelatin showed an increase in dose sensitivity of only 4% between dose rates of 100 and 600 cGy min-1, and provides an 80% greater dose sensitivity compared to Jordan’s standard gels with similar initial absorbance.

Biorepository for Prostate Cancer Prevention Trial (PCPT) | Division of Cancer Prevention

Cancer.gov

The PCPT biorepository and extended data was used to further explore the initial suggestion that some men taking finasteride were at risk of developing high-grade prostate cancers, and to look at the value of prostate-specific antigen (PSA) for early detection. Researchers showed that: |

Speaking of Vocation in an Age of Spirituality

ERIC Educational Resources Information Center

VanZanten Gallagher, Susan

2007-01-01

In 2003, the UCLA Higher Education Research Institute (HERI) began surveying undergraduates and faculty in a multi-institutional, longitudinal study designed to identify patterns of spirituality and religiousness among college students. Initial results revealed a high level of student interest in spiritual values, but they also showed that most…

Wellness of Counselor Educators: An Initial Look

ERIC Educational Resources Information Center

Wester, Kelly L.; Trepal, Heather C.; Myers, Jane E.

2009-01-01

This study with 180 counselor educators showed that, overall, educators appeared to have high levels of wellness. However, differences related to academic rank, children in the home, gender, and marital status were found. Perceived stress and number of children were found to have a negative impact on wellness. Implications for wellness are…

Is Memory Search Governed by Universal Principles or Idiosyncratic Strategies?

PubMed Central

Healey, M. Karl; Kahana, Michael J.

2013-01-01

Laboratory paradigms have provided an empirical foundation for much of psychological science. Some have argued, however, that such paradigms are highly susceptible to idiosyncratic strategies and that rather than reflecting fundamental cognitive principles, many findings are artifacts of averaging across participants who employ different strategies. We develop a set of techniques to rigorously test the extent to which average data are distorted by such strategy differences and apply these techniques to free recall data from the Penn Electrophysiology of Encoding and Retrieval Study (PEERS). Recall initiation showed evidence of subgroups: the majority of participants initiate recall from the last item in the list, but one subgroup show elevated initiation probabilities for items 2–4 back from the end of the list and another showed elevated probabilities for the beginning of the list. By contrast, serial position curves and temporal and semantic clustering functions were remarkably consistent, with almost every participant exhibiting a recognizable version of the average function, suggesting that these functions reflect fundamental principles of the memory system. The approach taken here can serve as a model for evaluating the extent to which other laboratory paradigms are influenced by individual differences in strategy use. PMID:23957279

Negative and Translation Termination-Dependent Positive Control of FLI-1 Protein Synthesis by Conserved Overlapping 5′ Upstream Open Reading Frames in Fli-1 mRNA

PubMed Central

Sarrazin, Sandrine; Starck, Joëlle; Gonnet, Colette; Doubeikovski, Alexandre; Melet, Fabrice; Morle, François

2000-01-01

The proto-oncogene Fli-1 encodes a transcription factor of the ets family whose overexpression is associated with multiple virally induced leukemias in mouse, inhibits murine and avian erythroid cell differentiation, and induces drastic perturbations of early development in Xenopus. This study demonstrates the surprisingly sophisticated regulation of Fli-1 mRNA translation. We establish that two FLI-1 protein isoforms (of 51 and 48 kDa) detected by Western blotting in vivo are synthesized by alternative translation initiation through the use of two highly conserved in-frame initiation codons, AUG +1 and AUG +100. Furthermore, we show that the synthesis of these two FLI-1 isoforms is regulated by two short overlapping 5′ upstream open reading frames (uORF) beginning at two highly conserved upstream initiation codons, AUG −41 and GUG −37, and terminating at two highly conserved stop codons, UGA +35 and UAA +15. The mutational analysis of these two 5′ uORF revealed that each of them negatively regulates FLI-1 protein synthesis by precluding cap-dependent scanning to the 48- and 51-kDa AUG codons. Simultaneously, the translation termination of the two 5′ uORF appears to enhance 48-kDa protein synthesis, by allowing downstream reinitiation at the 48-kDa AUG codon, and 51-kDa protein synthesis, by allowing scanning ribosomes to pile up and consequently allowing upstream initiation at the 51-kDa AUG codon. To our knowledge, this is the first example of a cellular mRNA displaying overlapping 5′ uORF whose translation termination appears to be involved in the positive control of translation initiation at both downstream and upstream initiation codons. PMID:10757781

Preparing high-density polymer brushes by mechanically assisted polymer assembly (MAPA)

NASA Astrophysics Data System (ADS)

Wu, Tao; Efimenko, Kirill; Genzer, Jan

2001-03-01

We introduce a novel method of modifying the surface properties of materials. This technique, called MAPA (="mechanically assisted polymer assembly"), is based on: 1) chemically attaching polymerization initiators to the surface of an elastomeric network that has been previously stretched by a certain length, Δx, and 2) growing end-anchored macromolecules using surface initiated ("grafting from") atom transfer living radical polymerization. After the polymerization, the strain is removed from the substrate, which returns to its original size causing the grafted macromolecules to stretch away from the substrate and form a dense polymer brush. We demonstrate the feasibility of the MAPA method by preparing high-density polymer brushes of poly(acryl amide), PAAm. We show that, as expected, the grafting density of the PAAm brushes can be increased by increasing Δx. We demonstrate that polymer brushes with extremely high grafting densities can be successfully prepared by MAPA.

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

Lincoln, D.E.

Preliminary analysis of two populations of Artemisia tridentata compared leaf chemical and physiological characteristics which influence herbivores. The proportion of sixteen of the volatile compounds differed significantly between the two populations; however, total yield of volatiles did not. This initial survey established the reliability of the procedure to quantitatively monitor plant responses to CO/sub 2/ enrichment and suggests that test samples be restricted to a single population. Four sesquiterpene lactones have been selected for the experimental quantitative HPLC analysis; all peaks have been assigned identities and have demonstrated high degree of reproducibility. Growth of Artemisia under high and low lightmore » at three CO/sub 2/ levels demonstrated that this species also undergoes a ''dilution'' of the leaf carbon content and is useful as test species for herbivory response to CO/sub 2/ induced effects. The initial experiment also showed that high irradiance is a necessary growth condition. 10 refs.« less

Successful treatment by pembrolizumab in a patient with end-stage renal disease with advanced non-small cell lung cancer and high PD-L1 expression.

PubMed

Ishizuka, Shiho; Sakata, Shinya; Yoshida, Chieko; Takaki, Akira; Saeki, Sho; Nakamura, Kazuyoshi; Fujii, Kazuhiko

2018-05-10

We report a 66-year-old Japanese male with end-stage renal disease (ESRD) and advanced non-small cell lung cancer (NSCLC) who was on hemodialysis. The patient harbored high programmed death ligand 1 (PD-L1) expression and was successfully treated with pembrolizumab. Laboratory examination upon diagnosis showed elevated serum creatinine (6.58 mg/dL). We administered pembrolizumab (200 mg/body) and repeated every 3 weeks. His renal dysfunction gradually progressed, hemodialysis was initiated after eight courses of pembrolizumab, and the antitumor effect was maintained at five months after hemodialysis initiation. Therefore, pembrolizumab can be administered for patients with ESRD and advanced NSCLC, who harbor high PD-L1 expression, during preparation for hemodialysis. Copyright © 2018 The Japanese Respiratory Society. Published by Elsevier B.V. All rights reserved.

[Response and adaptation of photosynthesis of cucumber seedlings to high temperature stress].

PubMed

Sun, Sheng Nan; Wang, Qiang; Sun, Chen Chen; Liu, Feng Jiao; Bi, Huan Gai; Ai, Xi Zhen

2017-05-18

Cucumber seedlings (Cucumis sativus Jinyou 35) were used to study the effects of high temperature (HT: 42 ℃/32 ℃) and sub-high temperature (SHT: 35 ℃/25 ℃) on its photosynthesis and growth. The results showed that the growth of cucumber seedlings was dramatically inhibited by the high and sub-high temperature stresses. The photosynthetic rate (P n ) was gradually reduced, while intercellular CO 2 concentration (C i ) was increased as heat stress lasted. Under heat stress, stomatal conductance (g s ), transpiration rate (T r ), photorespiration rate (P r ) and dark respiration rate (D r ) showed a trend from rise to decline in cucumber seedlings, which implied that heat-induced decline of photosynthesis was mainly due to non-stomatal limitation. Maximal photochemical efficiency of PS2 in darkness (F v /F m ), actual photochemical efficiency (χ PS 2 ), photochemical quenching (q P ) and electron transport rate (ETR) were severely hampered, while initial fluorescence (F o ) and non-chemical quenching (NPQ) were increased as a result of high and sub-high temperature stresses. Under extended high temperature stress, the activities of RuBP carboxylase (RuBPCase) and Rubisco activase (RCA) as well as the mRNA abundance of Rubisco and RCA were in the trend of decrease, while they were reduced 3 days following the sub-high temperature treatment. The activities and mRNA expressions of sedoheptulose-1,7-bisphosphatase (SBPase) and fructose 1,6-bisphosphate aldolase (FBA) increased initially, but decreased afterwards under heat stress. Taken together, our data suggested that short-term sub-high temperature did not cause photoinhibition under optimal light conditions, however, high temperature led to severe damage to PS2 reaction center in cucumber seedlings. The photosynthetic enzymes were induced by high temperature stress and the induction was affected by temperature and stress duration.

Reward Value-Contingent Changes of Visual Responses in the Primate Caudate Tail Associated with a Visuomotor Skill

PubMed Central

Kim, Hyoung F.; Hikosaka, Okihide

2013-01-01

A goal-directed action aiming at an incentive outcome, if repeated, becomes a skill that may be initiated automatically. We now report that the tail of the caudate nucleus (CDt) may serve to control a visuomotor skill. Monkeys looked at many fractal objects, half of which were always associated with a large reward (high-valued objects) and the other half with a small reward (low-valued objects). After several daily sessions, they developed a gaze bias, looking at high-valued objects even when no reward was associated. CDt neurons developed a response bias, typically showing stronger responses to high-valued objects. In contrast, their responses showed no change when object values were reversed frequently, although monkeys showed a strong gaze bias, looking at high-valued objects in a goal-directed manner. The biased activity of CDt neurons may be transmitted to the oculomotor region so that animals can choose high-valued objects automatically based on stable reward experiences. PMID:23825426

The High Power Electric Propulsion (HiPEP) Ion Thruster

NASA Technical Reports Server (NTRS)

Foster, John E.; Haag, Tom; Patterson, Michael; Williams, George J., Jr.; Sovey, James S.; Carpenter, Christian; Kamhawi, Hani; Malone, Shane; Elliot, Fred

2004-01-01

Practical implementation of the proposed Jupiter Icy Moon Orbiter (JIMO) mission, which would require a total delta V of approximately 38 km/s, will require the development of a high power, high specific impulse propulsion system. Initial analyses show that high power gridded ion thrusters could satisfy JIMO mission requirements. A NASA GRC-led team is developing a large area, high specific impulse, nominally 25 kW ion thruster to satisfy both the performance and the lifetime requirements for this proposed mission. The design philosophy and development status as well as a thruster performance assessment are presented.

Relaxation to a Phase-Locked Equilibrium State in a One-Dimensional Bosonic Josephson Junction

NASA Astrophysics Data System (ADS)

Pigneur, Marine; Berrada, Tarik; Bonneau, Marie; Schumm, Thorsten; Demler, Eugene; Schmiedmayer, Jörg

2018-04-01

We present an experimental study on the nonequilibrium tunnel dynamics of two coupled one-dimensional Bose-Einstein quasicondensates deep in the Josephson regime. Josephson oscillations are initiated by splitting a single one-dimensional condensate and imprinting a relative phase between the superfluids. Regardless of the initial state and experimental parameters, the dynamics of the relative phase and atom number imbalance shows a relaxation to a phase-locked steady state. The latter is characterized by a high phase coherence and reduced fluctuations with respect to the initial state. We propose an empirical model based on the analogy with the anharmonic oscillator to describe the effect of various experimental parameters. A microscopic theory compatible with our observations is still missing.

The Dorsolateral Prefrontal Cortex Plays a Role in Self-Initiated Elaborative Cognitive Processing during Episodic Memory Encoding: rTMS Evidence

PubMed Central

Hawco, Colin; Berlim, Marcelo T.; Lepage, Martin

2013-01-01

During episodic memory encoding, elaborative cognitive processing can improve later recall or recognition. While multiple studies examined the neural correlates of encoding strategies, few studies have explicitly focused on the self-initiation of elaborative encoding. Repetitive transcranial magnetic stimulation (rTMS), a method which can transiently disrupt neural activity, was administered during an associative encoding task. rTMS was either applied to the left dorsolateral prefrontal cortex (DLPFC) or to the vertex (a control region not involved in memory encoding) during presentation of pairs of words. Pairs could be semantically related or not related. Two encoding instructions were given, either cueing participants to analyze semantic relationships (cued condition), or to memorize the pair without any specific strategy cues (the self-initiated condition). Participants filled out a questionnaire regarding their use of memory strategies and performed a cued-recall task. We hypothesized that if the DLPFC plays a role in the self-initiation of elaborative encoding we would observe a reduction in memory performance in the self-initiated condition, particularly for related. We found a significant correlation between the effects of rTMS and strategy use, only in the self-initiated condition with related pairs. High strategy users showed reduced performance following DLPFC stimulation, while low strategy users tended to show increased recall following DLPFC stimulation during encoding. These results suggest the left DLPFC may be involved in the self-initiation of memory strategy use, and individuals may utilize different neural networks depending on their use of encoding strategies. PMID:24040072

RIO: a new computational framework for accurate initial data of binary black holes

NASA Astrophysics Data System (ADS)

Barreto, W.; Clemente, P. C. M.; de Oliveira, H. P.; Rodriguez-Mueller, B.

2018-06-01

We present a computational framework ( Rio) in the ADM 3+1 approach for numerical relativity. This work enables us to carry out high resolution calculations for initial data of two arbitrary black holes. We use the transverse conformal treatment, the Bowen-York and the puncture methods. For the numerical solution of the Hamiltonian constraint we use the domain decomposition and the spectral decomposition of Galerkin-Collocation. The nonlinear numerical code solves the set of equations for the spectral modes using the standard Newton-Raphson method, LU decomposition and Gaussian quadratures. We show the convergence of the Rio code. This code allows for easy deployment of large calculations. We show how the spin of one of the black holes is manifest in the conformal factor.

Forward Genetics Defines Xylt1 as a Key, Conserved Regulator of Early Chondrocyte Maturation and Skeletal Length

PubMed Central

Mis, Emily K.; Liem, Karel F.; Kong, Yong; Schwartz, Nancy B.; Domowicz, Miriam; Weatherbee, Scott D.

2014-01-01

The long bones of the vertebrate body are built by the initial formation of a cartilage template that is later replaced by mineralized bone. The proliferation and maturation of the skeletal precursor cells (chondrocytes) within the cartilage template and their replacement by bone is a highly coordinated process which, if misregulated, can lead to a number of defects including dwarfism and other skeletal deformities. This is exemplified by the fact that abnormal bone development is one of the most common types of human birth defects. Yet, many of the factors that initiate and regulate chondrocyte maturation are not known. We identified a recessive dwarf mouse mutant (pug) from an N-ethyl-N-nitrosourea (ENU) mutagenesis screen. pug mutant skeletal elements are patterned normally during development, but display a ~20% length reduction compared to wild-type embryos. We show that the pug mutation does not lead to changes in chondrocyte proliferation but instead promotes premature maturation and early ossification, which ultimately leads to disproportionate dwarfism. Using sequence capture and high-throughput sequencing, we identified a missense mutation in the Xylosyltransferase 1 (Xylt1) gene in pug mutants. Xylosyltransferases catalyze the initial step in glycosaminoglycan (GAG) chain addition to proteoglycan core proteins, and these modifications are essential for normal proteoglycan function. We show that the pug mutation disrupts Xylt1 activity and subcellular localization, leading to a reduction in GAG chains in pug mutants. The pug mutant serves as a novel model for mammalian dwarfism and identifies a key role for proteoglycan modification in the initiation of chondrocyte maturation. PMID:24161523

Evaluation and lessons learned from an undergraduate service learning course providing youth-focused relationship education.

PubMed

McElwain, Alyssa; Finnegan, Vanessa; Whittaker, Angela; Kerpelman, Jennifer; Adler-Baeder, Francesca; Duke, Adrienne

2016-10-01

Adolescent romantic relationships are known to have a significant impact on individual well-being and development. However, few teens experience formal education about the knowledge and skills necessary for building healthy romantic relationships. In response, a statewide relationship education initiative was developed at a large university in a Southeastern state. Undergraduates who enrolled in a service learning course in Human Development and Family Studies partnered with this initiative and implemented a relationship education program targeting high school students. A service learning model is used in this initiative because it offers opportunities for students' professional development and experiential learning. The present article provides a formative and illustrative summative evaluation of the service learning program. Specifically, the primary aims of this paper are to 1) provide an overview of the service learning course components; 2) describe preparation of the service learning students and their implementation of the relationship education program; 3) discuss challenges and lessons learned; and 4) offer initial evidence of effectiveness by showing change in targeted outcomes for the high school student recipients of the relationship education program. Copyright © 2016 Elsevier Ltd. All rights reserved.

A Framework for Assessing High School Students' Statistical Reasoning.

PubMed

Chan, Shiau Wei; Ismail, Zaleha; Sumintono, Bambang

2016-01-01

Based on a synthesis of literature, earlier studies, analyses and observations on high school students, this study developed an initial framework for assessing students' statistical reasoning about descriptive statistics. Framework descriptors were established across five levels of statistical reasoning and four key constructs. The former consisted of idiosyncratic reasoning, verbal reasoning, transitional reasoning, procedural reasoning, and integrated process reasoning. The latter include describing data, organizing and reducing data, representing data, and analyzing and interpreting data. In contrast to earlier studies, this initial framework formulated a complete and coherent statistical reasoning framework. A statistical reasoning assessment tool was then constructed from this initial framework. The tool was administered to 10 tenth-grade students in a task-based interview. The initial framework was refined, and the statistical reasoning assessment tool was revised. The ten students then participated in the second task-based interview, and the data obtained were used to validate the framework. The findings showed that the students' statistical reasoning levels were consistent across the four constructs, and this result confirmed the framework's cohesion. Developed to contribute to statistics education, this newly developed statistical reasoning framework provides a guide for planning learning goals and designing instruction and assessments.

A Framework for Assessing High School Students' Statistical Reasoning

PubMed Central

2016-01-01

Based on a synthesis of literature, earlier studies, analyses and observations on high school students, this study developed an initial framework for assessing students’ statistical reasoning about descriptive statistics. Framework descriptors were established across five levels of statistical reasoning and four key constructs. The former consisted of idiosyncratic reasoning, verbal reasoning, transitional reasoning, procedural reasoning, and integrated process reasoning. The latter include describing data, organizing and reducing data, representing data, and analyzing and interpreting data. In contrast to earlier studies, this initial framework formulated a complete and coherent statistical reasoning framework. A statistical reasoning assessment tool was then constructed from this initial framework. The tool was administered to 10 tenth-grade students in a task-based interview. The initial framework was refined, and the statistical reasoning assessment tool was revised. The ten students then participated in the second task-based interview, and the data obtained were used to validate the framework. The findings showed that the students’ statistical reasoning levels were consistent across the four constructs, and this result confirmed the framework’s cohesion. Developed to contribute to statistics education, this newly developed statistical reasoning framework provides a guide for planning learning goals and designing instruction and assessments. PMID:27812091

Numerical studies on alpha production from high energy proton beam interaction with Boron

NASA Astrophysics Data System (ADS)

Moustaizis, S. D.; Lalousis, P.; Hora, H.; Korn, G.

2017-05-01

Numerical investigations on high energy proton beam interaction with high density Boron plasma allows to simulate conditions concerning the alpha production from recent experimental measurements . The experiments measure the alpha production due to p11B nuclear fusion reactions when a laser-driven high energy proton beam interacts with Boron plasma produced by laser beam interaction with solid Boron. The alpha production and consequently the efficiency of the process depends on the initial proton beam energy, proton beam density, the Boron plasma density and temperature, and their temporal evolution. The main advantage for the p11B nuclear fusion reaction is the production of three alphas with total energy of 8.9 MeV, which could enhance the alpha heating effect and improve the alpha production. This particular effect is termed in the international literature as the alpha avalanche effect. Numerical results using a multi-fluid, global particle and energy balance, code shows the alpha production efficiency as a function of the initial energy of the proton beam, the Boron plasma density, the initial Boron plasma temperature and the temporal evolution of the plasma parameters. The simulations enable us to determine the interaction conditions (proton beam - B plasma) for which the alpha heating effect becomes important.

X-ray imaging and 3D reconstruction of in-flight exploding foil initiator flyers

DOE PAGES

Willey, T. M.; Champley, K.; Hodgin, R.; ...

2016-06-17

Exploding foil initiators (EFIs), also known as slapper initiators or detonators, offer clear safety and timing advantages over other means of initiating detonation in high explosives. The work described here outlines a new capability for imaging and reconstructing three-dimensional images of operating EFIs. Flyer size and intended velocity were chosen based on parameters of the imaging system. The EFI metal plasma and plastic flyer traveling at 2.5 km/s were imaged with short ~80 ps pulses spaced 153.4 ns apart. A four-camera system acquired 4 images from successive x-ray pulses from each shot. The first frame was prior to bridge burst,more » the 2 nd images the flyer about 0.16 mm above the surface but edges of the foil and/or flyer are still attached to the substrate. The 3 rd frame captures the flyer in flight, while the 4 th shows a completely detached flyer in a position that is typically beyond where slappers strike initiating explosives. Multiple acquisitions at different incident angles and advanced computed tomography reconstruction algorithms were used to produce a 3-dimensional image of the flyer at 0.16 and 0.53 mm above the surface. Both the x-ray images and the 3D reconstruction show a strong anisotropy in the shape of the flyer and underlying foil parallel vs. perpendicular to the initiating current and electrical contacts. These results provide detailed flyer morphology during the operation of the EFI.« less

X-ray imaging and 3D reconstruction of in-flight exploding foil initiator flyers

NASA Astrophysics Data System (ADS)

Willey, T. M.; Champley, K.; Hodgin, R.; Lauderbach, L.; Bagge-Hansen, M.; May, C.; Sanchez, N.; Jensen, B. J.; Iverson, A.; van Buuren, T.

2016-06-01

Exploding foil initiators (EFIs), also known as slapper initiators or detonators, offer clear safety and timing advantages over other means of initiating detonation in high explosives. This work outlines a new capability for imaging and reconstructing three-dimensional images of operating EFIs. Flyer size and intended velocity were chosen based on parameters of the imaging system. The EFI metal plasma and plastic flyer traveling at 2.5 km/s were imaged with short ˜80 ps pulses spaced 153.4 ns apart. A four-camera system acquired 4 images from successive x-ray pulses from each shot. The first frame was prior to bridge burst, the 2nd images the flyer about 0.16 mm above the surface but edges of the foil and/or flyer are still attached to the substrate. The 3rd frame captures the flyer in flight, while the 4th shows a completely detached flyer in a position that is typically beyond where slappers strike initiating explosives. Multiple acquisitions at different incident angles and advanced computed tomography reconstruction algorithms were used to produce a 3-dimensional image of the flyer at 0.16 and 0.53 mm above the surface. Both the x-ray images and the 3D reconstruction show a strong anisotropy in the shape of the flyer and underlying foil parallel vs. perpendicular to the initiating current and electrical contacts. These results provide detailed flyer morphology during the operation of the EFI.

X-ray imaging and 3D reconstruction of in-flight exploding foil initiator flyers

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

Willey, T. M., E-mail: willey1@llnl.gov; Champley, K., E-mail: champley1@llnl.gov; Hodgin, R.

Exploding foil initiators (EFIs), also known as slapper initiators or detonators, offer clear safety and timing advantages over other means of initiating detonation in high explosives. This work outlines a new capability for imaging and reconstructing three-dimensional images of operating EFIs. Flyer size and intended velocity were chosen based on parameters of the imaging system. The EFI metal plasma and plastic flyer traveling at 2.5 km/s were imaged with short ∼80 ps pulses spaced 153.4 ns apart. A four-camera system acquired 4 images from successive x-ray pulses from each shot. The first frame was prior to bridge burst, the 2nd images themore » flyer about 0.16 mm above the surface but edges of the foil and/or flyer are still attached to the substrate. The 3rd frame captures the flyer in flight, while the 4th shows a completely detached flyer in a position that is typically beyond where slappers strike initiating explosives. Multiple acquisitions at different incident angles and advanced computed tomography reconstruction algorithms were used to produce a 3-dimensional image of the flyer at 0.16 and 0.53 mm above the surface. Both the x-ray images and the 3D reconstruction show a strong anisotropy in the shape of the flyer and underlying foil parallel vs. perpendicular to the initiating current and electrical contacts. These results provide detailed flyer morphology during the operation of the EFI.« less

X-ray imaging and 3D reconstruction of in-flight exploding foil initiator flyers

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

Willey, T. M.; Champley, K.; Hodgin, R.

Exploding foil initiators (EFIs), also known as slapper initiators or detonators, offer clear safety and timing advantages over other means of initiating detonation in high explosives. The work described here outlines a new capability for imaging and reconstructing three-dimensional images of operating EFIs. Flyer size and intended velocity were chosen based on parameters of the imaging system. The EFI metal plasma and plastic flyer traveling at 2.5 km/s were imaged with short ~80 ps pulses spaced 153.4 ns apart. A four-camera system acquired 4 images from successive x-ray pulses from each shot. The first frame was prior to bridge burst,more » the 2 nd images the flyer about 0.16 mm above the surface but edges of the foil and/or flyer are still attached to the substrate. The 3 rd frame captures the flyer in flight, while the 4 th shows a completely detached flyer in a position that is typically beyond where slappers strike initiating explosives. Multiple acquisitions at different incident angles and advanced computed tomography reconstruction algorithms were used to produce a 3-dimensional image of the flyer at 0.16 and 0.53 mm above the surface. Both the x-ray images and the 3D reconstruction show a strong anisotropy in the shape of the flyer and underlying foil parallel vs. perpendicular to the initiating current and electrical contacts. These results provide detailed flyer morphology during the operation of the EFI.« less

Selectivity in the inelastic rotational scattering of D2 and HD molecules from graphite: Similarities and differences respect to the H2 case

NASA Astrophysics Data System (ADS)

Rutigliano, Maria; Pirani, Fernando

2018-03-01

The inelastic scattering of D2 and HD molecules impinging on a graphite surface in well-defined initial roto-vibrational states has been studied by using the computational setup recently developed to characterize important selectivities in the molecular dynamics occurring at the gas-surface interface. In order to make an immediate comparison of determined elastic and inelastic scattering probabilities, we considered for D2 and HD molecules the same initial states, as well as the same collision energy range, previously selected for the investigation of H2 behaviour. The analysis of the back-scattered molecules shows that, while low-lying initial vibrational states are preserved, the medium-high initial ones give rise to final states covering the complete ladder of vibrational levels, although with different probability for the various cases investigated. Moreover, propensities in the formation of the final rotational states are found to depend strongly on the initial ones, on the collision energy, and on the isotopologue species.

Employability and personal initiative as antecedents of job satisfaction.

PubMed

Gamboa, Juan Pablo; Gracia, Francisco; Ripoll, Pilar; Peiró, José María

2009-11-01

In a changing and flexible labour market it is important to clarify the role of environmental and personal variables that contribute to obtaining adequate levels of job satisfaction. The aim of the present study is to analyze the direct effects of employability and personal initiative on intrinsic, extrinsic and social job satisfaction, clarifying their cumulative and interactive effects. The study has been carried out in a sample of 1319 young Spanish workers. Hypotheses were tested by means of the moderated hierarchical regression analysis. Results show that employability and personal initiative predict in a cumulative way the intrinsic, extrinsic and social job satisfaction. Moreover, the interaction between employability and personal initiative increases the prediction of these two variables on intrinsic and extrinsic job satisfaction. Results also indicate that higher values of employability when initiative is also high are associated to higher levels of intrinsic and extrinsic satisfaction. These results have implications for theory and practice in a context of new employment relations.

Dynamic delamination crack propagation in a graphite/epoxy laminate

NASA Technical Reports Server (NTRS)

Grady, J. E.; Sun, C. T.

1991-01-01

Dynamic delamination crack propagation in a (90/0) 5s Graphite/Epoxy laminate with an embedded interfacial crack was investigated experimentally using high speed photography. The dynamic motion was produced by impacting the beamlike laminate specimen with a silicon rubber ball. The threshold impact velocities required to initiate dynamic crack propagation in laminates with varying initial crack positions were determined. The crack propagation speeds were estimated from the photographs. Results show that the through the thickness position of the embedded crack can significantly affect the dominant mechanism and the threshold impact velocity for the onset of crack movement. If the initial delamination is placed near the top of bottom surface of the laminate, local buckling of the delaminated plies may cause instability of the crack. If the initial delamination lies on the midplane, local buckling does not occur and the initiation of crack propagation appears to be dominated by Mode II fracture. The crack propagation and arrest observed was seen to be affected by wave motion within the delamination region.

Dissection of the internal carotid artery and stroke after mandibular fractures: a case report and review of the literature.

PubMed

Tveita, Ingrid Aune; Madsen, Martin Ragnar Skjerve; Nielsen, Erik Waage

2017-06-02

We present a report of a patient with blunt trauma and mandibular fractures who developed a significant cerebral infarction due to an initially unrecognized injury of her left internal carotid artery. We believe that increased knowledge of this association will facilitate early recognition and hence prevention of a devastating outcome. A 41-year-old ethnic Norwegian woman presented to our Emergency Room after a bicycle accident that had caused a direct blow to her chin. At admittance, her Glasgow Coma Scale was 15. Initial trauma computed tomography showed triple fractures of her mandible, but no further pathology. She was placed in our Intensive Care Unit awaiting open reduction of her mandibular fractures. During the following 9 hours, she showed recurrent episodes of confusion and a progressive right-sided hemiparesis. Repeated cerebral computed tomography revealed no further pathology compared to the initial scan. She had magnetic resonance angiography 17 hours after admittance, which showed dissection and thrombus formation in her left internal carotid artery, total occlusion of her left medial cerebral artery, and left middle cerebral artery infarction was detected. Carotid artery dissection is a rare but life-threatening condition that can develop after trauma to the head and neck. There should be a high index of suspicion in patients with a mechanism of injury that places the internal carotid artery at risk because blunt vascular injury may show delayed onset with no initial symptoms of vascular damage. By implementing an algorithm for early detection and treatment of these injuries, serious brain damage may be avoided.

Large-scale mechanical buckle fold development and the initiation of tensile fractures

NASA Astrophysics Data System (ADS)

Eckert, Andreas; Connolly, Peter; Liu, Xiaolong

2014-11-01

failure associated with buckle folding is commonly associated to the distribution of outer arc extension but has also been observed on fold limbs. This study investigates whether tensile stresses and associated failure can be explained by the process of buckling under realistic in situ stress conditions. A 2-D plane strain finite element modeling approach is used to study single-layer buckle folds with a Maxwell viscoelastic rheology. A variety of material parameters are considered and their influence on the initiation of tensile stresses during the various stages of deformation is analyzed. It is concluded that the buckling process determines the strain distribution within the fold layer but is not solely responsible for the initiation of tensile stresses. The modeling results show that tensile stresses are most dependent on the permeability, viscosity, and overburden thickness. Low permeability (<10-19 m2), high viscosity (≥1021 Pa s), and low overburden pressure can explain tensile failure at the fold hinge. Tensile stresses in the limb of the fold cannot (in general) be explained by buckling. Rather, it develops due to a combination of compression and erosional unloading. The modeling results show that erosion of high permeability rocks can explain the generation of tensile stresses at significant depths (˜2 km) both at the hinge of the fold and throughout the limb of the fold. This study shows that tensile stresses and associated failure within buckle folds is directly dependent on the distribution of material parameters but moreover to the strain history of the geologic system.

Holographic thermalization with initial long range correlation

DOE PAGES

Lin, Shu

2016-01-19

Here, we studied the evolution of the Wightman correlator in a thermalizing state modeled by AdS 3-Vaidya background. A prescription was given for calculating the Wightman correlator in coordinate space without using any approximation. For equal-time correlator , we obtained an enhancement factor v 2 due to long range correlation present in the initial state. This was missed by previous studies based on geodesic approximation. Moreover, we found that the long range correlation in initial state does not lead to significant modification to thermalization time as compared to known results with generic initial state. We also studied the spatially integratedmore » Wightman correlator and showed evidence on the distinction between long distance and small momentum physics for an out-of-equilibrium state. We also calculated the radiation spectrum of particles weakly coupled to O and found that lower frequency mode approaches thermal spectrum faster than high frequency mode.« less

Observations of the initial stage of a rocket-and-wire-triggered lightning discharge

NASA Astrophysics Data System (ADS)

Zhang, Yang; Krehbiel, Paul R.; Zhang, Yijun; Lu, Weitao; Zheng, Dong; Xu, Liangtao; Huang, Zhigang

2017-05-01

Observations have been obtained of the initial stage of a rocket-and-wire-triggered lightning flash with a high-resolution broadband VHF interferometer. The discharge produced 54 precursor current pulses (PCPs) over 883 ms during the rocket's ascent. The interferometer observations show that the PCPs were produced by breakdown at the ascending tip of the rocket, and that individual PCPs were produced by weak upward positive breakdown over meters-scale distances, followed by more energetic, fast downward negative breakdown over several tens of meters distance. The average propagation speeds were 5 × 106 m s-1 and 3 × 107 m s-1, respectively. The sustained upward positive leader (UPL) was initiated by a rapid, repetitive burst of 14 precursor pulses. Upon initiation, the VHF radiation abruptly became continuous with time. Significantly, breakdown during the UPL appeared to extend the discharge in a similar manner to that of the precursor pulses.

Tree-level correlations in the strong field regime

NASA Astrophysics Data System (ADS)

Gelis, François

2017-09-01

We consider the correlation function of an arbitrary number of local observables in quantum field theory, in situations where the field amplitude is large. Using a quasi-classical approximation (valid for a highly occupied initial mixed state, or for a coherent initial state if the classical dynamics has instabilities), we show that at tree level these correlations are dominated by fluctuations at the initial time. We obtain a general expression of the correlation functions in terms of the classical solution of the field equation of motion and its derivatives with respect to its initial conditions, that can be arranged graphically as the sum of labeled trees where the nodes are the individual observables, and the links are pairs of derivatives acting on them. For 3-point (and higher) correlation functions, there are additional tree-level terms beyond the quasi-classical approximation, generated by fluctuations in the bulk.

A novel two-level dielectric barrier discharge reactor for methyl orange degradation.

PubMed

Tao, Xumei; Wang, Guowei; Huang, Liang; Ye, Qingguo; Xu, Dongyan

2016-12-15

A novel pilot two-level dielectric barrier discharge (DBD) reactor has been proposed and applied for degradation of continuous model wastewater. The two-level DBD reactor was skillfully realized with high space utilization efficiency and large contact area between plasma and wastewater. Various conditions such as applied voltage, initial concentration and initial pH value on methyl orange (MO) model wastewater degradation were investigated. The results showed that the appropriate applied voltage was 13.4 kV; low initial concentration and low initial pH value were conducive for MO degradation. The percentage removal of 4 L MO with concentration of 80 mg/L reached 94.1% after plasma treatment for 80min. Based on ultraviolet spectrum (UV), Infrared spectrum (IR), liquid chromatography-mass spectrometry (LC-MS) analysis of degradation intermediates and products, insights in the degradation pathway of MO were proposed. Copyright © 2016 Elsevier Ltd. All rights reserved.

Exploring Initiative as a Signal of Knowledge Co-Construction During Collaborative Problem Solving.

PubMed

Howard, Cynthia; Di Eugenio, Barbara; Jordan, Pamela; Katz, Sandra

2017-08-01

Peer interaction has been found to be conducive to learning in many settings. Knowledge co-construction (KCC) has been proposed as one explanatory mechanism. However, KCC is a theoretical construct that is too abstract to guide the development of instructional software that can support peer interaction. In this study, we present an extensive analysis of a corpus of peer dialogs that we collected in the domain of introductory Computer Science. We show that the notion of task initiative shifts correlates with both KCC and learning. Speakers take task initiative when they contribute new content that advances problem solving and that is not invited by their partner; if initiative shifts between the partners, it indicates they both contribute to problem solving. We found that task initiative shifts occur more frequently within KCC episodes than outside. In addition, task initiative shifts within KCC episodes correlate with learning for low pre-testers, and total task initiative shifts correlate with learning for high pre-testers. As recognizing task initiative shifts does not require as much deep knowledge as recognizing KCC, task initiative shifts as an indicator of productive collaboration are potentially easier to model in instructional software that simulates a peer. Copyright © 2016 Cognitive Science Society, Inc.

Initiated Chemical Vapor Deposition (iCVD) of Highly Cross-Linked Polymer Films for Advanced Lithium-Ion Battery Separators.

PubMed

Yoo, Youngmin; Kim, Byung Gon; Pak, Kwanyong; Han, Sung Jae; Song, Heon-Sik; Choi, Jang Wook; Im, Sung Gap

2015-08-26

We report an initiated chemical vapor deposition (iCVD) process to coat polyethylene (PE) separators in Li-ion batteries with a highly cross-linked, mechanically strong polymer, namely, polyhexavinyldisiloxane (pHVDS). The highly cross-linked but ultrathin pHVDS films can only be obtained by a vapor-phase process, because the pHVDS is insoluble in most solvents and thus infeasible with conventional solution-based methods. Moreover, even after the pHVDS coating, the initial porous structure of the separator is well preserved owing to the conformal vapor-phase deposition. The coating thickness is delicately controlled by deposition time to the level that the pore size decreases to below 7% compared to the original dimension. The pHVDS-coated PE shows substantially improved thermal stability and electrolyte wettability. After incubation at 140 °C for 30 min, the pHVDS-coated PE causes only a 12% areal shrinkage (versus 90% of the pristine separator). The superior wettability results in increased electrolyte uptake and ionic conductivity, leading to significantly improved rate performance. The current approach is applicable to a wide range of porous polymeric separators that suffer from thermal shrinkage and poor electrolyte wetting.

The moderating effects of culture on peer deviance and alcohol use among high-risk African-American Adolescents.

PubMed

Nasim, Aashir; Belgrave, Faye Z; Jagers, Robert J; Wilson, Karen D; Owens, Kristal

2007-01-01

African-American adolescents have lower rates of alcohol consumption than White youth. However, African-American youth suffer disproportionately more adverse social, mental, and physical health outcomes related to alcohol use. Affiliating with negative peers is a risk factor for alcohol initiation and consumption. Cultural variables have shown moderating effects against other risk factors for African-American youth and therefore were the focus of this study. Specifically, we tested whether three culturally-relevant variables, Africentric beliefs, religiosity, and ethnic identity were promotive or protective for alcohol initiation and use within the context of negative peer affiliations. The sample consisted of 114 at-risk African-American adolescents whose ages ranged from 13 to 20. Participants were administered a questionnaire with measures of alcohol initiation and use, peer risk behaviors, ethnic identity, Africentric beliefs, religiosity, and demographic items. Peer risk behaviors accounted for significant percentages of the variance in age of alcohol initiation, lifetime use, and current and heavy alcohol use after adjusting for age and gender. Cultural variables showed both promotive and protective effects. Africentric beliefs were promotive of delayed alcohol initiation, whereas both Africentrism and religiosity moderated peer risk behaviors effect on alcohol initiation. Africentric beliefs were also inversely related to lifetime alcohol use revealing a promotive effect. Moreover, there were significant protective effects of ethnic identity and religiosity on heavy alcohol consumption. One implication of these findings is that prevention programs that infuse cultural values and practices such as Africentrism, ethnic identity, and religiosity may delay alcohol initiation and reduce use especially for youth with high risk peers.

Immigration, race/ethnicity, and social and economic factors as predictors of breastfeeding initiation.

PubMed

Celi, Ann C; Rich-Edwards, Janet W; Richardson, Marcie K; Kleinman, Ken P; Gillman, Matthew W

2005-03-01

To determine the impact of immigration status as well as race/ethnicity and social and economic factors on breastfeeding initiation. Cohort. Multisite group practice in eastern Massachusetts. One thousand eight hundred twenty-nine pregnant women prospectively followed up in Project Viva. Whether the participant breastfed her infant. The overall breastfeeding initiation rate was 83%. In multivariate models that included race/ethnicity and social, economic, and demographic factors, foreign-born women were more likely to initiate breastfeeding than US-born women (odds ratio [OR], 3.2 [95% confidence interval (CI), 2.0-5.2]). In models stratified by both race/ethnicity and immigration status, and further adjusted for whether the mother herself was breastfed as an infant and the mother's parents' immigration status, US-born and foreign-born black and Hispanic women initiated breastfeeding at rates at least as high as US-born white women (US-born black vs US-born white women, OR, 1.2 [95% CI, 0.8-1.9], US-born Hispanic vs US-born white women, OR, 1.1 [95% CI, 0.6-1.9], foreign-born black vs US-born white women, OR, 2.6 [95% CI, 1.1-6.0], and foreign-born Hispanic vs US-born white women, OR, 1.8 [95% CI, 0.7-4.8]). Calculations of predicted prevalences showed that, for example, the 2.6-fold increase in odds for the foreign-born black vs US-born white women translated to an increase in probability of approximately 1.4. Higher maternal education and household income also predicted higher initiation rates. Immigration status was strongly associated with increased breastfeeding initiation in this cohort, implying that cultural factors are important in the decision to breastfeed. Immigrants of all races/ethnicities initiated breastfeeding more often than their US-born counterparts. In addition, US-born minority groups initiated breastfeeding at rates at least as high as their white counterparts, likely due in part to high levels of education and income as well as to access to a medical care system that explicitly supports breastfeeding.

A modified adaptive algorithm of dealing with the high chirp when chirped pulses propagating in optical fiber

NASA Astrophysics Data System (ADS)

Wu, Lianglong; Fu, Xiquan; Guo, Xing

2013-03-01

In this paper, we propose a modified adaptive algorithm (MAA) of dealing with the high chirp to efficiently simulate the propagation of chirped pulses along an optical fiber for the propagation distance shorter than the "temporal focal length". The basis of the MAA is that the chirp term of initial pulse is treated as the rapidly varying part by means of the idea of the slowly varying envelope approximation (SVEA). Numerical simulations show that the performance of the MAA is validated, and that the proposed method can decrease the number of sampling points by orders of magnitude. In addition, the computational efficiency of the MAA compared with the time-domain beam propagation method (BPM) can be enhanced with the increase of the chirp of initial pulse.

[Life styles in adolescence: sexual behavior of Portuguese adolescents].

PubMed

Ferreira, Maria Margarida da Silva Reis Dos Santos; Torgal, Maria Constança Leite de Freitas Paúl Reis

2011-06-01

Recent studies have shown that adolescents have initiated their sex lives earlier and earlier, without, however, receiving consistent sex education. The objectives of this study were to analyze the sexual behavior of adolescent high school students and identify the habits of sexual health in sexually active adolescent high school students. An exploratory study was conducted with 680 adolescents, whose age ranged between 15 and 19 years. Results showed that most participants had not initiated their sex life; boys are those who most report having had sexual relations; not all the interviewed adolescents used condoms during sex; most adolescents do not practice sexual health surveillance. It is important for sexually active adolescents to receive health care and counseling. Health institutions and their workers must be proactive in trying to approach adolescents.

Humor as aggression: effects of motivation on hostility expressed in humor appreciation.

PubMed

Weinstein, Netta; Hodgins, Holley S; Ostvik-White, Elin

2011-06-01

In 4 studies, the authors examined the hypothesis that relative to primed autonomy motivation, primed control would increase enjoyment of hostile (compared with nonhostile) humor as assessed by self-reported enjoyment and aversiveness and by nonverbal behavior. Results confirmed the hypothesis. Furthermore, initial state hostility moderated the effect such that high-hostility participants who were primed with control motivation especially enjoyed hostile humor. The 2 final studies showed that the effect was mediated by implicit aggression such that the combination of high initial state hostility and control priming led to implicit aggression, which in turn resulted in hostile humor enjoyment. Results are interpreted in terms of the effects of autonomy versus control motivation on intrapersonal self-regulatory processes, which influence interpersonal functioning. 2011 APA, all rights reserved

CD4+ cell count recovery in naïve patients initiating cART, who achieved and maintained plasma HIV-RNA suppression.

PubMed

Costagliola, Dominique; Lacombe, Jean-Marc; Ghosn, Jade; Delaugerre, Constance; Pialoux, Gilles; Cuzin, Lise; Launay, Odile; Ménard, Amélie; de Truchis, Pierre; Mary-Krause, Murielle; Weiss, Laurence; Delfraissy, Jean-François

2014-01-01

A key objective of combined antiretroviral therapy (cART) is to reach and maintain high CD4 cell counts to provide long-term protection against AIDS-defining opportunistic infections and malignancies, as well as other comorbidities. However, a high proportion of patients present late for care. Our objective was to assess CD4 cell count recovery up to seven years in naïve patients initiating cART with at least three drugs in usual clinical care. From the French Hospital Database on HIV, we selected naïve individuals initiating cART from 2000 with at least two years of follow-up. Participants were further required to have achieved viral load suppression by six months after initiating cART and were censored in case of virological failure. We calculated the proportion of patients (Kaplan-Meier estimates) who achieved CD4 recovery to >500/mm(3) according to baseline CD4 cell count. A total of 15,025 patients were analyzed with a median follow-up on ART of 65.5 months (IQR: 42.3-96.0). At cART initiation, the median age was 38.6 years (IQR: 32.2-46.0), 9734 (64.8%) were men, median CD4 cell count was 239 (IQR: 130-336) and 2668 (17.8%) had a prior AIDS event. RESULTS are presented in the Table 1. This study shows that CD4 cell counts continue to increase seven years after cART initiation, whatever the baseline CD4 cell count. Failing to achieve CD4 recovery with continuous viral load suppression is rare for naïve patients initiating cART in routine clinical practice, but takes substantially longer in patients who initiate antiretroviral therapy at low CD4 cell counts.

A multi-directional tracer test in the fractured Chalk aquifer of E. Yorkshire, UK.

PubMed

Hartmann, S; Odling, N E; West, L J

2007-12-07

A multi-borehole radial tracer test has been conducted in the confined Chalk aquifer of E. Yorkshire, UK. Three different tracer dyes were injected into three injection boreholes and a central borehole, 25 m from the injection boreholes, was pumped at 330 m(3)/d for 8 days. The breakthrough curves show that initial breakthrough and peak times were fairly similar for all dyes but that recoveries varied markedly from 9 to 57%. The breakthrough curves show a steep rise to a peak and long tail, typical of dual porosity aquifers. The breakthrough curves were simulated using a 1D dual porosity model. Model input parameters were constrained to acceptable ranges determined from estimations of matrix porosity and diffusion coefficient, fracture spacing, initial breakthrough times and bulk transmissivity of the aquifer. The model gave equivalent hydraulic apertures for fractures in the range 363-384 microm, dispersivities of 1 to 5 m and matrix block sizes of 6 to 9 cm. Modelling suggests that matrix block size is the primary controlling parameter for solute transport in the aquifer, particularly for recovery. The observed breakthrough curves suggest results from single injection-borehole tracer tests in the Chalk may give initial breakthrough and peak times reasonably representative of the aquifer but that recovery is highly variable and sensitive to injection and abstraction borehole location. Consideration of aquifer heterogeneity suggests that high recoveries may be indicative of a high flow pathway adjacent, but not necessarily connected, to the injection and abstraction boreholes whereas low recoveries may indicate more distributed flow through many fractures of similar aperture.

Online Friendship, Romance, and Sex: Properties and Associations of the Online Relationship Initiation Scale.

PubMed

Harris, Keith M; Aboujaoude, Elias

2016-08-01

Online relationships are increasingly central to many people's lives. As a result, there is a growing need to scientifically examine their psychosocial implications. This study developed and tested the Online Relationship Initiation Scale (ORIS) through classical and item response theory analyses to address this need. An anonymous online survey included 713 adults, aged 18-71 years. The ORIS was tested on psychometric properties and examined for associations with gender and several standardized psychosocial measures. Results demonstrated unidimensionality of nine items, strong factor loadings, and high internal consistency (α = 0.90, ωt = 0.94). All items captured significant information on the latent trait and none showed differential item functioning by sex, age group, or ethnicity. General linear modeling confirmed hypotheses that men were more likely than women to initiate online relationships. Online relationship initiation was not strongly associated with perceived social support, but was positively related to financial distress, and willingness to engage in infidelity or unprotected sex. The ORIS was negatively associated with age and satisfaction with life and showed modest interactions with ethnicity and hours online. This study provided empirical evidence for an interpersonal relationship initiation construct. The ORIS was shown to be a psychometrically sound instrument for evaluating online interpersonal behaviors and their associations with psychosocial and demographic factors. Such psychometrically sound instruments can be useful in exploring online interpersonal behaviors and their significance.

Consequences of germline variation disrupting the constitutional translational initiation codon start sites of MLH1 and BRCA2: use of potential alternative start sites and implications for predicting variant pathogenicity

PubMed Central

Parsons, Michael T.; Whiley, Phillip J.; Beesley, Jonathan; Drost, Mark; de Wind, Niels; Thompson, Bryony A.; Marquart, Louise; Hopper, John L.; Jenkins, Mark A.; Brown, Melissa A.; Tucker, Kathy; Warwick, Linda; Buchanan, Daniel D.; Spurdle, Amanda B.

2014-01-01

Variants that disrupt the translation initiation sequences in cancer predisposition genes are generally assumed to be deleterious. However few studies have validated these assumptions with functional and clinical data. Two cancer syndrome gene variants likely to affect native translation initiation were identified by clinical genetic testing: MLH1:c.1A>G p.(Met1?) and BRCA2:c.67+3A>G. In vitro GFP-reporter assays were conducted to assess the consequences of translation initiation disruption on alternative downstream initiation codon usage. Analysis of MLH1:c.1A>G p.(Met1?) showed that translation was mostly initiated at an in-frame position 103 nucleotides downstream, but also at two ATG sequences downstream. The protein product encoded by the in-frame transcript initiating from position c.103 showed loss of in vitro mismatch repair activity comparable to known pathogenic mutations. BRCA2:c.67+3A>G was shown by mRNA analysis to result in an aberrantly spliced transcript deleting exon 2 and the consensus ATG site. In the absence of exon 2, translation initiated mostly at an out-of-frame ATG 323 nucleotides downstream, and to a lesser extent at an in-frame ATG 370 nucleotides downstream. Initiation from any of the downstream alternative sites tested in both genes would lead to loss of protein function, but further clinical data is required to confirm if these variants are associated with a high cancer risk. Importantly, our results highlight the need for caution in interpreting the functional and clinical consequences of variation that leads to disruption of the initiation codon, since translation may not necessarily occur from the first downstream alternative start site, or from a single alternative start site. PMID:24302565

Initial stage corrosion of nanocrystalline copper particles and thin films

NASA Astrophysics Data System (ADS)

Tao, Weimin

1997-12-01

Corrosion behavior is an important issue in nanocrystalline materials research and development. A very fine grain size is expected to have significant effects on the corrosion resistance of these novel materials. However, both the macroscopic corrosion properties and the corresponding structure evolution during corrosion have not been fully studied. Under such circumstances, conducting fundamental research in this area is important and necessary. In this study, high purity nanocrystalline and coarse-grained copper were selected as our sample material, sodium nitrite aqueous solution at room temperature and air at a high temperature were employed as corrosive environments. The weight loss testing and electrochemical methods were used to obtain the macroscopic corrosion properties, whereas the high resolution transmission electron microscope was employed for the structure analysis. The weight loss tests indicate that the corrosion rate of nanocrystalline copper is about 5 times higher than that of coarse-grained copper at the initial stage of corrosion. The electrochemical measurements show that the corrosion potential of the nanocrystalline copper has a 230 mV negative shift in comparison with that of the coarse-grained copper. The nanocrystalline copper also exhibits a significantly higher exchange current density than the coarse-grained copper. High resolution TEM revealed that the surface structure changes at the initial stage of corrosion. It was found that the first copper oxide layer formed on the surface of nanocrystalline copper thin film contains a large density of high angle grain boundaries, whereas that formed on the surface of coarse-grained copper shows highly oriented oxide nuclei and appears to show a strong tendency for forming low angle grain boundaries. A correlation between the macroscopic corrosion properties and the structure characteristics is proposed for the nanocrystalline copper based on the concept of the "apparent" exchange current density associated with mass transport of ions in the oxide layer. A hypothesis is developed that the high corrosion rate of the nanocrystalline copper is closely associated with the structure of the copper oxide layer. Therefore, a high "apparent" exchange current density for the nanocrystalline copper is associated with the high angle grain boundary structure in the initial oxide layer. Additional structure analysis was also carried out: (a) High resolution TEM imaging has provided a cross sectional view of the epitaxial interface between nanocrystalline copper and copper (I) oxide and explicitly discloses the presence of interface defects such as misfit dislocations. Based on this observation, a mechanism was proposed to explain the Cu/Cusb2O interface misfit accommodation. This appears to be the first time this interface has been directly examined. (b) A nanocrystalline analogue to a cross-section of Gwathmey's copper single crystal sphere was revealed by high resolution TEM imaging. A partially oxidized nanocrystalline copper particle is used to examine the variation of the Cu/Cusb2O orientation relationship with respect to changes in surface orientation. A new orientation relationship, Cu (011) //Cusb2O (11), ˜ Cu(011)//Cusb2O(111), was found for the oxidation of nanocrystalline copper.

Characterization of Porous, Dexamethasone-Releasing Polyurethane Coatings for Glucose Sensors

PubMed Central

Vallejo-Heligon, Suzana G.; Klitzman, Bruce; Reichert, William M.

2014-01-01

Commercially available implantable needle-type glucose sensors for diabetes management are robust analytically but can be unreliable clinically primarily due to tissue-sensor interactions. Here, we present the physical, drug release, and bioactivity characterization of tubular, porous dexamethasone (Dex) releasing polyurethane coatings designed to attenuate local inflammation in the tissue-sensor interface. Porous polyurethane coatings were produced by the salt-leaching/gas-foaming method. Scanning electron microscopy (SEM) and Micro-computed tomography (Micro-CT) showed a controlled porosity and coating thickness. In vitro drug release from coatings monitored over two weeks presented an initial fast release followed by a slower release. Total release from coatings was highly dependent on initial drug loading amount. Functional in vitro testing of glucose sensors deployed with porous coatings against glucose standards demonstrated that highly porous coatings minimally affected signal strength and response rate. Bioactivity of the released drug was determined by monitoring Dex-mediated, dose-dependent apoptosis of human peripheral blood derived monocytes in culture. Acute animal studies were used to determine the appropriate Dex payload for the implanted porous coatings. Pilot short-term animal studies showed that Dex released from porous coatings implanted in rat subcutis attenuated the initial inflammatory response to sensor implantation. These results suggest that deploying sensors with the porous, Dex-releasing coatings is a promising strategy to improve glucose sensor performance. PMID:25065548

Ultrasonic degradation of acetaminophen in water: effect of sonochemical parameters and water matrix.

PubMed

Villaroel, Erica; Silva-Agredo, Javier; Petrier, Christian; Taborda, Gonzalo; Torres-Palma, Ricardo A

2014-09-01

This paper deals about the sonochemical water treatment of acetaminophen (ACP, N-acetyl-p-aminophenol or paracetamol), one of the most popular pharmaceutical compounds found in natural and drinking waters. Effect of ultrasonic power (20-60 W), initial ACP concentration (33-1323 μmol L(-1)) and pH (3-12) were evaluated. High ultrasonic powers and, low and natural acidic pH values favored the efficiency of the treatment. Effect of initial substrate concentration showed that the Langmuir-type kinetic model fit well the ACP sonochemical degradation. The influence of organic compounds in the water matrix, at concentrations 10-fold higher than ACP, was also evaluated. The results indicated that only organic compounds having a higher value of the Henry's law constant than the substrate decrease the efficiency of the treatment. On the other hand, ACP degradation in mineral natural water showed to be strongly dependent of the initial substrate concentration. A positive matrix effect was observed at low ACP concentrations (1.65 μmol L(-1)), which was attributed to the presence of bicarbonate ion in solution. However, at relative high ACP concentrations a detrimental effect of matrix components was noticed. Finally, the results indicated that ultrasonic action is able to transform ACP in aliphatic organic compounds that could be subsequently eliminated in a biological system. Copyright © 2014 Elsevier B.V. All rights reserved.

Contribution of the Axon Initial Segment to Action Potentials Recorded Extracellularly.

PubMed

Teleńczuk, Maria; Brette, Romain; Destexhe, Alain; Teleńczuk, Bartosz

2018-01-01

Action potentials (APs) are electric phenomena that are recorded both intracellularly and extracellularly. APs are usually initiated in the short segment of the axon called the axon initial segment (AIS). It was recently proposed that at the onset of an AP the soma and the AIS form a dipole. We study the extracellular signature [the extracellular AP (EAP)] generated by such a dipole. First, we demonstrate the formation of the dipole and its extracellular signature in detailed morphological models of a reconstructed pyramidal neuron. Then, we study the EAP waveform and its spatial dependence in models with axonal AP initiation and contrast it with the EAP obtained in models with somatic AP initiation. We show that in the models with axonal AP initiation the dipole forms between somatodendritic compartments and the AIS, and not between soma and dendrites as in the classical models. The soma-dendrites dipole is present only in models with somatic AP initiation. Our study has consequences for interpreting extracellular recordings of single-neuron activity and determining electrophysiological neuron types, but also for better understanding the origins of the high-frequency macroscopic extracellular potentials recorded in the brain.

FoxP3 Functions as a Novel Breast Cancer Suppressor Gene Through Cooperation with NFAT

DTIC Science & Technology

2008-12-01

peared transformed, as demonstrated by enlargement of nuclei and more-active nucleoli (Figure 6C). In most mice, multiple PINs were found in the...papillary and tufting. A high-power imagine showing enlarged nuclei and active nucleoli is presented in the lower panel.tissue is sufficient to initiate

Breaking the Cycle of Educational Alienation: A Multiprofessional Approach

ERIC Educational Resources Information Center

Williams, Richard; Pritchard, Colin

2006-01-01

In this groundbreaking book, the authors show how the cycle of educational alienation can be broken, to enable parents and schools to work together to contribute to children's educational, social and emotional well-being. They illustrate this by exploring a highly successful initiative in a school with severe socioeconomic disadvantages, which, in…

The Influence of Anxiety on the Initial Selection of Emotional Faces Presented in Binocular Rivalry

ERIC Educational Resources Information Center

Gray, Katie L. H.; Adams, Wendy J.; Garner, Matthew

2009-01-01

Neurocognitive theories of anxiety predict that threat-related information can be evaluated before attentional selection, and can influence behaviour differentially in high anxious compared to low anxious individuals. We investigate this further by presenting emotional and neutral faces in an adapted binocular rivalry paradigm. We show that the…

Projecting insect voltinism under high and low greenhouse gas emission conditions

Treesearch

Shi Chen; Shelby J. Fleischer; Patrick C. Tobin; Michael C. Saunders

2011-01-01

We develop individual-based Monte Carlo methods to explore how climate change can alter insect voltinism under varying greenhouse gas emissions scenarios by using input distributions of diapause termination or spring emergence, development rate, and diapause initiation, linked to daily temperature and photoperiod. We show concurrence of these projections with a field...

Collaboration, Communities, and Covey: A Model for Personal and Professional Change.

ERIC Educational Resources Information Center

Birrell, James R.; Ostlund, Margaret R.; Eagan, M. Winston; Young, James R.; Cook, Paul F.; DeWitt, Paul F.; Tibbitts, Cathy B.

1998-01-01

Reports on one school-university partnership that used S. Covey's "The 7 Habits of Highly Effective People" as a framework for initiating and sustaining teacher-education reform in an elementary school. Discusses how the collaboration overcame a difficult start involving distrust of the university. Shows how the project illuminates three…

Integrated Thermal Modules for Cooling Silicon and Silicon Carbide Power Modules

DTIC Science & Technology

2007-06-11

analyses, bench tests, and motor tests comprise the program. The ITMs, in place of standard heatsinks, use a highly conductive pyrolytic graphite to...passively cool power modules. Initial results show that even simple ITMs can lower chip temperatures by 20 deg. C and 10 deg. C with engine oil and

Fast Disinfecting Antimicrobial Surfaces

PubMed Central

Madkour, Ahmad E.; Dabkowski, Jeffery M.; Nüsslein, Klaus; Tew, Gregory N.

2013-01-01

Silicon wafers and glass surfaces were functionalized with facially amphiphilic antimicrobial copolymers using the “grafting from” technique. Surface initiated atom transfer radical polymerization (ATRP) was used to grow poly(butylmethacrylate)-co-poly(Boc-aminoethyl methacrylate) from the surfaces. Upon Boc-deprotection, these surfaces became highly antimicrobial and killed S. aureus and E. coli 100% in less than 5 min. The molecular weight and grafting density of the polymer were controlled by varying the polymerization time and initiator surface density. Antimicrobial studies showed that the killing efficiency of these surfaces was independent of polymer layer thickness or grafting density within the range of surfaces studied. PMID:19177651

Impulsive Collision Dynamics of CO Super Rotors from an Optical Centrifuge.

PubMed

Murray, Matthew J; Ogden, Hannah M; Toro, Carlos; Liu, Qingnan; Mullin, Amy S

2016-11-18

We report state-resolved collision dynamics for CO molecules prepared in an optical centrifuge and measured with high-resolution transient IR absorption spectroscopy. Time-resolved polarization-sensitive measurements of excited CO molecules in the J=29 rotational state reveal that the oriented angular momentum of CO rotors is relaxed by impulsive collisions. The translational energy gains for molecules in the initial plane of rotation are threefold larger than for randomized angular momentum orientations, indicating the presence of anisotropic kinetic energy. The transient data show enhanced population for CO molecules in the initial plane of rotation immediately following the optical centrifuge pulse. A comparison with previous CO 2 super rotor studies illustrates the behavior of molecular gyroscopes; spatial reorientation of CO 2 J=76 rotors takes substantially longer than that for CO J=29 rotors, despite similarities in classical rotational period and rotational energy gap. High-resolution transient IR absorption measurements of the CO J=29-39 rotational states show that the collisional depopulation rates increase with J quantum number. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

An essential role for the RNA-binding protein Smaug during the Drosophila maternal-to-zygotic transition.

PubMed

Benoit, Beatrice; He, Chun Hua; Zhang, Fan; Votruba, Sarah M; Tadros, Wael; Westwood, J Timothy; Smibert, Craig A; Lipshitz, Howard D; Theurkauf, William E

2009-03-01

Genetic control of embryogenesis switches from the maternal to the zygotic genome during the maternal-to-zygotic transition (MZT), when maternal mRNAs are destroyed, high-level zygotic transcription is initiated, the replication checkpoint is activated and the cell cycle slows. The midblastula transition (MBT) is the first morphological event that requires zygotic gene expression. The Drosophila MBT is marked by blastoderm cellularization and follows 13 cleavage-stage divisions. The RNA-binding protein Smaug is required for cleavage-independent maternal transcript destruction during the Drosophila MZT. Here, we show that smaug mutants also disrupt syncytial blastoderm stage cell-cycle delays, DNA replication checkpoint activation, cellularization, and high-level zygotic expression of protein coding and micro RNA genes. We also show that Smaug protein levels increase through the cleavage divisions and peak when the checkpoint is activated and zygotic transcription initiates, and that transgenic expression of Smaug in an anterior-to-posterior gradient produces a concomitant gradient in the timing of maternal transcript destruction, cleavage cell cycle delays, zygotic gene transcription, cellularization and gastrulation. Smaug accumulation thus coordinates progression through the MZT.

Socialisation scheme with a high staff-patient ratio.

PubMed

Hollander, D; Rao, V B; McManoman, E; Harrington, N; Weeks, A; Mann, A

1981-01-01

Six months after a comprehensive socialisation scheme began, a prospective controlled study was carried out. The patients were tested in three practical sections - Cooking; Maintenance of Home and Clothing; Other Skills (eg. form-filling); and with a Questionnaire. Forty-eight members of an experimental group received socialisation training after initial testing. They and the 20 controls who did not undergo training were re-evaluated three months later. There was no significant difference between the groups in their initial scores. On retesting, the experimental group showed a significant improvement in Cooking (p less than 0.001), Home Maintenance (p less than 0.001) and the Questionnaire (p less than 0.05). Analysis of the inter-group differences showed significant superiority of the experimental group in Cooking (p less than 0.05) and Home Maintenance (p less than 0.05). It is suggested that such a socialisation scheme be considered for inclusion alongside other rehabilitation services in psychiatric hospitals. The emphasis on a high staff-to-patient ratio and the breakdown of each task into smaller steps emerged as essential elements in the training programme.

Coseismic temporal changes of slip direction: the effect of absolute stress on dynamic rupture

USGS Publications Warehouse

Guatteri, Mariagiovanna; Spudich, P.

1998-01-01

We investigate the dynamics of rupture at low-stress level. We show that one main difference between the dynamics of high- and low-stress events is the amount of coseismic temporal rake rotation occurring at given points on the fault. Curved striations on exposed fault surfaces and earthquake dislocation models derived from ground-motion inversion indicate that the slip direction may change with time at a point on the fault during dynamic rupture. We use a 3D boundary integral method to model temporal rake variations during dynamic rupture propagation assuming a slip-weakening friction law and isotropic friction. The points at which the slip rotates most are characterized by an initial shear stress direction substantially different from the average stress direction over the fault plane. We show that for a given value of stress drop, the level of initial shear stress (i.e., the fractional stress drop) determines the amount of rotation in slip direction. We infer that seismic events that show evidence of temporal rake rotations are characterized by a low initial shear-stress level with spatially variable direction on the fault (possibly due to changes in fault surface geometry) and an almost complete stress drop.Our models motivate a new interpretation of curved and cross-cutting striations and put new constraints on their analysis. The initial rake is in general collinear with the initial stress at the hypocentral zone, supporting the assumptions made in stress-tensor inversion from first-motion analysis. At other points on the fault, especially away from the hypocenter, the initial slip rake may not be collinear with the initial shear stress, contradicting a common assumption of structural geology. On the other hand, the later part of slip in our models is systematically more aligned with the average stress direction than the early slip. Our modeling suggests that the length of the straight part of curved striations is usually an upper bound of the slip-weakening distance if this parameter is uniform over the fault plane, and the direction of the late part of slip of curved striations should have more weight in the estimate of initial stress direction.

Onset time of hyperkalaemia after angiotensin receptor blocker initiation: when should we start serum potassium monitoring?

PubMed

Park, I-W; Sheen, S S; Yoon, D; Lee, S-H; Shin, G-T; Kim, H; Park, R W

2014-02-01

Angiotensin receptor blockers (ARBs) frequently induce hyperkalaemia in high-risk patients. Early detection of hyperkalaemia can reduce the subsequent harmful effects. This study was performed to examine the onset time of hyperkalaemia after ARB therapy. We carried out a retrospective analysis to determine the onset time of hyperkalaemia (serum potassium >5·5 mm) among hospitalized patients newly starting ARB therapy between 2004 and 2012, in a tertiary teaching hospital. Predefined possible risk factors and concomitant medications were evaluated. During the 97-month study period, a total of 4267 hospitalized patients started ARBs as new drugs and 225 patients showed hyperkalaemia. A significantly increased risk of hyperkalaemia was detected among patients with a high baseline potassium [odds ratio (OR) 6·0] and those who took non-potassium-sparing diuretics (OR 2·2) or potassium supplements (OR 1·6). A high glomerular filtration rate (GFR) was associated with a lower risk of hyperkalaemia (OR 0·992). Fifty-two percentage of hyperkalaemic events occurred within the first week after initiation of ARB therapy. The highest frequency of hyperkalaemia occurred on the first day after initiation of ARBs. Hyperkalaemia occurred earlier in patients with a high baseline serum potassium level, reduced GFR, diabetes and in those without heart failure. Hyperkalaemia occurs most frequently at the beginning of ARB therapy in hospitalized patients. Monitoring of serum potassium and estimated GFR after initiation of ARBs should be started within a few days or not later than 1 week, especially in patients with risk factors. © 2013 John Wiley & Sons Ltd.

STAR FORMATION IN TURBULENT MOLECULAR CLOUDS WITH COLLIDING FLOW

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

Matsumoto, Tomoaki; Dobashi, Kazuhito; Shimoikura, Tomomi, E-mail: matsu@hosei.ac.jp

2015-03-10

Using self-gravitational hydrodynamical numerical simulations, we investigated the evolution of high-density turbulent molecular clouds swept by a colliding flow. The interaction of shock waves due to turbulence produces networks of thin filamentary clouds with a sub-parsec width. The colliding flow accumulates the filamentary clouds into a sheet cloud and promotes active star formation for initially high-density clouds. Clouds with a colliding flow exhibit a finer filamentary network than clouds without a colliding flow. The probability distribution functions (PDFs) for the density and column density can be fitted by lognormal functions for clouds without colliding flow. When the initial turbulence ismore » weak, the column density PDF has a power-law wing at high column densities. The colliding flow considerably deforms the PDF, such that the PDF exhibits a double peak. The stellar mass distributions reproduced here are consistent with the classical initial mass function with a power-law index of –1.35 when the initial clouds have a high density. The distribution of stellar velocities agrees with the gas velocity distribution, which can be fitted by Gaussian functions for clouds without colliding flow. For clouds with colliding flow, the velocity dispersion of gas tends to be larger than the stellar velocity dispersion. The signatures of colliding flows and turbulence appear in channel maps reconstructed from the simulation data. Clouds without colliding flow exhibit a cloud-scale velocity shear due to the turbulence. In contrast, clouds with colliding flow show a prominent anti-correlated distribution of thin filaments between the different velocity channels, suggesting collisions between the filamentary clouds.« less

Low clouds suppress Arctic air formation and amplify high-latitude continental winter warming.

PubMed

Cronin, Timothy W; Tziperman, Eli

2015-09-15

High-latitude continents have warmed much more rapidly in recent decades than the rest of the globe, especially in winter, and the maintenance of warm, frost-free conditions in continental interiors in winter has been a long-standing problem of past equable climates. We use an idealized single-column atmospheric model across a range of conditions to study the polar night process of air mass transformation from high-latitude maritime air, with a prescribed initial temperature profile, to much colder high-latitude continental air. We find that a low-cloud feedback--consisting of a robust increase in the duration of optically thick liquid clouds with warming of the initial state--slows radiative cooling of the surface and amplifies continental warming. This low-cloud feedback increases the continental surface air temperature by roughly two degrees for each degree increase of the initial maritime surface air temperature, effectively suppressing Arctic air formation. The time it takes for the surface air temperature to drop below freezing increases nonlinearly to ∼ 10 d for initial maritime surface air temperatures of 20 °C. These results, supplemented by an analysis of Coupled Model Intercomparison Project phase 5 climate model runs that shows large increases in cloud water path and surface cloud longwave forcing in warmer climates, suggest that the "lapse rate feedback" in simulations of anthropogenic climate change may be related to the influence of low clouds on the stratification of the lower troposphere. The results also indicate that optically thick stratus cloud decks could help to maintain frost-free winter continental interiors in equable climates.

Low clouds suppress Arctic air formation and amplify high-latitude continental winter warming

PubMed Central

Cronin, Timothy W.; Tziperman, Eli

2015-01-01

High-latitude continents have warmed much more rapidly in recent decades than the rest of the globe, especially in winter, and the maintenance of warm, frost-free conditions in continental interiors in winter has been a long-standing problem of past equable climates. We use an idealized single-column atmospheric model across a range of conditions to study the polar night process of air mass transformation from high-latitude maritime air, with a prescribed initial temperature profile, to much colder high-latitude continental air. We find that a low-cloud feedback—consisting of a robust increase in the duration of optically thick liquid clouds with warming of the initial state—slows radiative cooling of the surface and amplifies continental warming. This low-cloud feedback increases the continental surface air temperature by roughly two degrees for each degree increase of the initial maritime surface air temperature, effectively suppressing Arctic air formation. The time it takes for the surface air temperature to drop below freezing increases nonlinearly to ∼10 d for initial maritime surface air temperatures of 20 °C. These results, supplemented by an analysis of Coupled Model Intercomparison Project phase 5 climate model runs that shows large increases in cloud water path and surface cloud longwave forcing in warmer climates, suggest that the “lapse rate feedback” in simulations of anthropogenic climate change may be related to the influence of low clouds on the stratification of the lower troposphere. The results also indicate that optically thick stratus cloud decks could help to maintain frost-free winter continental interiors in equable climates. PMID:26324919

Advanced high efficiency wraparound contact solar cell

NASA Technical Reports Server (NTRS)

Scott-Monck, J. A.; Uno, F. M.; Thornhill, J. W.

1977-01-01

A significant advancement in the development of thin high efficiency wraparound contact silicon solar cells has been made by coupling space and terrestrial processing procedures. Although this new method for fabricating cells has not been completely reduced to practice, some of the initial cells have delivered over 20 mW/sq cm when tested at 25 C under AMO intensity. This approach not only yields high efficiency devices, but shows promise of allowing complete freedom of choice in both the location and size of the wraparound contact pad area.

Advanced high efficiency wraparound contact solar cell

NASA Technical Reports Server (NTRS)

Scott-Monck, J. A.; Uno, F. M.; Thornhill, J. W.

1977-01-01

A significant advancement in the development of thin high efficiency wraparound contact silicon solar cells has been made by coupling space and terrestrial processing procedures. Although this new method for fabricating cells has not been completely reduced to practice, some of the initial cells have delivered over 20 mW/sq cm when tested at 25 C under AMO intensity. This approach not only yields high efficiency devices, but shows promise of allowing complete freedom of choice in both the location and size of the wraparound contact pad area

M xMn 8O 16 (M = Ag or K) as promising cathode materials for secondary Mg based batteries: The role of the cation M

DOE PAGES

Huang, Jianping; Takeuchi, Esther S.; Altug S. Poyraz; ...

2016-01-01

Here, Ag xMn 8O 16 (Ag-OMS-2) and K xMn 8O 16 (K-OMS-2) were investigated as high voltage cathode materials for Mg based batteries. Both M xMn 8O 16 materials delivered high initial capacities (>180 mA h g –1), and K xMn 8O 16 showed high cycle stability with a reversible capacity of >170 mA h g –1 after 20 cycles.

Wind-tunnel measurement of noise emitted by helicopter rotors at high speed

NASA Astrophysics Data System (ADS)

Prieur, J.

Measurements of high-speed impulsive helicopter rotor noise in a wind-tunnel are presented. High-speed impulsive noise measurements have been performed in 1988 in the ONERA S2ch wind-tunnel, fitted with an acoustic lining, on two types of rotors. They show that substantial noise reduction is obtained with sweptback tips, initially designed for aerodynamic purposes, which lower transonic effects on the advancing blade tip. Emphasis is placed on the necessity of taking into account the acoustic annoyance problem, using noise prediction tools, when designing new helicopter blades.

Bilateral asymmetry of skin temperature is not related to bilateral asymmetry of crank torque during an incremental cycling exercise to exhaustion

PubMed Central

Formenti, Damiano; Ludwig, Nicola; Gargano, Marco; Bosio, Andrea; Rampinini, Ermanno; Alberti, Giampietro

2018-01-01

Although moderate relationships (|r| ∼ 0.5) were reported between skin temperature and performance-related variables (e.g., kinetic), it remains unclear whether skin temperature asymmetry reflects muscle force imbalance in cycling. Therefore, the aim of this study was to assess whether a relationship exists between kinetic and thermal asymmetry during a fatiguing exercise. Ten elite cyclists were enrolled and tested on a maximal incremental cycling test. Peak crank torques of both legs were obtained at the initial and final workload. Likewise, bilateral skin temperatures were recorded before and after exercise. Asymmetric indexes were also calculated for kinetic (AIK) and skin temperature (AIT) outcomes. The bilateral peak crank torques showed a larger difference at the final compared to the initial workload (p < 0.05) of the incremental exercise. Conversely, the bilateral skin temperature did not show any differences at both initial and final workload (p > 0.05). Additionally, trivial relationships were reported between AIK and AIT (−0.3 < r < 0.2) at the initial and final workload. The obtained results showed that changes in bilateral kinetic values did not reflect concurrent changes in bilateral skin temperatures. This finding emphasizes the difficulty of associating the asymmetry of skin temperature with those of muscle effort in elite cyclists. Lastly, our study also provided further insights on thermal skin responses during exhaustive cycling exercise in very highly-trained athletes. PMID:29507831

Dual Megathrust Slip Behaviors of the 2014 Iquique Earthquake Sequence

NASA Astrophysics Data System (ADS)

Meng, L.; Huang, H.; Burgmann, R.; Ampuero, J. P.; Strader, A. E.

2014-12-01

The transition between seismic rupture and aseismic creep is of central interest to better understand the mechanics of subduction processes. A M 8.2 earthquake occurred on April 1st, 2014 in the Iquique seismic gap of Northern Chile. This event was preceded by a 2-week-long foreshock sequence including a M 6.7 earthquake. Repeating earthquakes are found among the foreshock sequence that migrated towards the mainshock area, suggesting a large scale slow-slip event on the megathrust preceding the mainshock. The variations of the recurrence time of repeating earthquakes highlights the diverse seismic and aseismic slip behaviors on different megathrust segments. The repeaters that were active only before the mainshock recurred more often and were distributed in areas of substantial coseismic slip, while other repeaters occurred both before and after the mainshock in the area complementary to the mainshock rupture. The spatial and temporal distribution of the repeating earthquakes illustrate the essential role of propagating aseismic slip in leading up to the mainshock and aftershock activities. Various finite fault models indicate that the coseismic slip generally occurred down-dip from the foreshock activity and the mainshock hypocenter. Source imaging by teleseismic back-projection indicates an initial down-dip propagation stage followed by a rupture-expansion stage. In the first stage, the finite fault models show slow initiation with low amplitude moment rate at low frequency (< 0.1 Hz), while back-projection shows a steady initiation at high frequency (> 0.5 Hz). This indicates frequency-dependent manifestations of seismic radiation in the low-stress foreshock region. In the second stage, the high-frequency rupture remains within an area of low gravity anomaly, suggesting possible upper-crustal structures that promote high-frequency generation. Back-projection also shows an episode of reverse rupture propagation which suggests a delayed failure of asperities in the foreshock area. Our results highlight the complexity of the interactions between large-scale aseismic slow-slip and dynamic ruptures of megathrust earthquakes.

Radiation Damage Workshop

NASA Technical Reports Server (NTRS)

Stella, P. M.

1984-01-01

The availability of data regarding the radiation behavior of GaAs and silicon solar cells is discussed as well as efforts to provide sufficient information. Other materials are considered too immature for reasonable radiation evaluation. The lack of concern over the possible catastrophic radiation degradation in cascade cells is a potentially serious problem. Lithium counterdoping shows potential for removing damage in irradiated P-type material, although initial efficiencies are not comparable to current state of the art. The possibility of refining the lithium doping method to maintain high initial efficiencies and combining it with radiation tolerant structures such as thin BSF cells or vertical junction cells could provide a substantial improvement in EOL efficiencies. Laser annealing of junctions, either those formed ion implantation or diffusion, may not only improve initial cell performance but might also reduce the radiation degradation rate.

Cell-type-specific replication initiation programs set fragility of the FRA3B fragile site.

PubMed

Letessier, Anne; Millot, Gaël A; Koundrioukoff, Stéphane; Lachagès, Anne-Marie; Vogt, Nicolas; Hansen, R Scott; Malfoy, Bernard; Brison, Olivier; Debatisse, Michelle

2011-02-03

Common fragile sites have long been identified by cytogeneticists as chromosomal regions prone to breakage upon replication stress. They are increasingly recognized to be preferential targets for oncogene-induced DNA damage in pre-neoplastic lesions and hotspots for chromosomal rearrangements in various cancers. Common fragile site instability was attributed to the fact that they contain sequences prone to form secondary structures that may impair replication fork movement, possibly leading to fork collapse resulting in DNA breaks. Here we show, in contrast to this view, that the fragility of FRA3B--the most active common fragile site in human lymphocytes--does not rely on fork slowing or stalling but on a paucity of initiation events. Indeed, in lymphoblastoid cells, but not in fibroblasts, initiation events are excluded from a FRA3B core extending approximately 700 kilobases, which forces forks coming from flanking regions to cover long distances in order to complete replication. We also show that origins of the flanking regions fire in mid-S phase, leaving the site incompletely replicated upon fork slowing. Notably, FRA3B instability is specific to cells showing this particular initiation pattern. The fact that both origin setting and replication timing are highly plastic in mammalian cells explains the tissue specificity of common fragile site instability we observed. Thus, we propose that common fragile sites correspond to the latest initiation-poor regions to complete replication in a given cell type. For historical reasons, common fragile sites have been essentially mapped in lymphocytes. Therefore, common fragile site contribution to chromosomal rearrangements in tumours should be reassessed after mapping fragile sites in the cell type from which each tumour originates.

A Study on the Mechanical Properties and Impact-Induced Initiation Characteristics of Brittle PTFE/Al/W Reactive Materials.

PubMed

Ge, Chao; Maimaitituersun, Wubuliaisan; Dong, Yongxiang; Tian, Chao

2017-04-26

Polytetrafluoroethylene/aluminum/tungsten (PTFE/Al/W) reactive materials of three different component mass ratios (73.5/26.5/0, 68.8/24.2/7 and 63.6/22.4/14) were studied in this research. Different from the PTFE/Al/W composites published elsewhere, the materials in our research were fabricated under a much lower sintering temperature and for a much shorter duration to achieve a brittle property, which aims to provide more sufficient energy release upon impact. Quasi-static compression tests, dynamic compression tests at room and elevated temperatures, and drop weight tests were conducted to evaluate the mechanical and impact-induced initiation characteristics of the materials. The materials before and after compression tests were observed by a scanning electron microscope to relate the mesoscale structural characteristics to their macro properties. All the three types of materials fail at very low strains during both quasi-static and dynamic compression. The stress-strain curves for quasi-static tests show obvious deviations while that for the dynamic tests consist of only linear-elastic and failure stages typically. The materials were also found to exhibit thermal softening at elevated temperatures and were strain-rate sensitive during dynamic tests, which were compared using dynamic increase factors (DIFs). Drop-weight test results show that the impact-initiation sensitivity increases with the increase of W content due to the brittle mechanical property. The high-speed video sequences and recovered sample residues of the drop-weight tests show that the reaction is initiated at two opposite positions near the edges of the samples, where the shear force concentrates the most intensively, indicating a shear-induced initiation mechanism.

A Study on the Mechanical Properties and Impact-Induced Initiation Characteristics of Brittle PTFE/Al/W Reactive Materials

PubMed Central

Ge, Chao; Maimaitituersun, Wubuliaisan; Dong, Yongxiang; Tian, Chao

2017-01-01

Polytetrafluoroethylene/aluminum/tungsten (PTFE/Al/W) reactive materials of three different component mass ratios (73.5/26.5/0, 68.8/24.2/7 and 63.6/22.4/14) were studied in this research. Different from the PTFE/Al/W composites published elsewhere, the materials in our research were fabricated under a much lower sintering temperature and for a much shorter duration to achieve a brittle property, which aims to provide more sufficient energy release upon impact. Quasi-static compression tests, dynamic compression tests at room and elevated temperatures, and drop weight tests were conducted to evaluate the mechanical and impact-induced initiation characteristics of the materials. The materials before and after compression tests were observed by a scanning electron microscope to relate the mesoscale structural characteristics to their macro properties. All the three types of materials fail at very low strains during both quasi-static and dynamic compression. The stress-strain curves for quasi-static tests show obvious deviations while that for the dynamic tests consist of only linear-elastic and failure stages typically. The materials were also found to exhibit thermal softening at elevated temperatures and were strain-rate sensitive during dynamic tests, which were compared using dynamic increase factors (DIFs). Drop-weight test results show that the impact-initiation sensitivity increases with the increase of W content due to the brittle mechanical property. The high-speed video sequences and recovered sample residues of the drop-weight tests show that the reaction is initiated at two opposite positions near the edges of the samples, where the shear force concentrates the most intensively, indicating a shear-induced initiation mechanism. PMID:28772812

Shock Initiation and Equation of State of Ammonium Nitrate

NASA Astrophysics Data System (ADS)

Robbins, David; Sheffield, Steve; Dattelbaum, Dana; Chellappa, Raja; Velisavljevic, Nenad

2013-06-01

Ammonium nitrate (AN) is a widely used fertilizer and mining explosive commonly found in ammonium nitrate-fuel oil. Neat AN is a non-ideal explosive with measured detonation velocities approaching 4 km/s. Previously, we reported a thermodynamically-complete equation of state for AN based on its maximum density, and showed that near-full density AN did not initiate when subjected to shock input conditions up to 22 GPa. In this work, we extend these initial results, by presenting new Hugoniot data for intermediate density neat AN obtained from gas gun-driven plate impact experiments. AN at densities from 1.8 to 1.5 g/cm3 were impacted into LiF windows using a two-stage light gas gun. Dual VISARs were used to measure the interfacial particle velocity wave profile as a function of time following impact. The new Hugoniot data, in addition to updates to thermodynamic parameters derived from structural analysis and vibrational spectroscopy measurements in high pressure diamond anvil cell experiments, are used to refine the unreacted EOS for AN. Furthermore, shock initiation of neat AN was observed as the initial porosity increased (density decreased). Insights into the relationship(s) between initial density and shock initiation sensitivity are also presented, from evidence of shock initiation in the particle velocity profiles obtained for the lower density AN samples.

Investigation of heat transfer in zirconium potassium perchlorate at low temperature: A study of the failure mechanism of the NASA standard initiator

NASA Technical Reports Server (NTRS)

Varghese, Philip L.

1989-01-01

The objective of this work was to study the reasons for the failure of pyrotechnic initiators at very low temperatures (10 to 100 K). A two-dimensional model of the NASA standard initiator was constructed to model heat transfer from the electrically heated stainless steel bridgewire to the zirconium potassium perchlorate explosive charge and the alumina charge cup. Temperature dependent properties were used in the model to simulate initiator performance over a wide range of initial temperatures (10 to 500 K). A search of the thermophysical property data base showed that pure alumina has a very high thermal conductivity at low temperatures. It had been assumed to act as a thermal insulator in all previous analyses. Rapid heat transfer from the bridgewire to the alumina at low initial temperatures was shown to cause failure of the initiators if the wire did not also make good contact with the zirconium potassium perchlorate charge. The mode is able to reproduce the results of the tests that had been conducted to investigate the cause for failure. It also provides an explanation for previously puzzling results and suggests simple design changes that will increase reliability at very low initial temperatures.

Longitudinal hydrodynamics from event-by-event Landau initial conditions

DOE PAGES

Sen, Abhisek; Gerhard, Jochen; Torrieri, Giorgio; ...

2015-02-02

Here we investigate three-dimensional ideal hydrodynamic evolution, with Landau initial conditions, incorporating event-by-event variation with many events and transverse density inhomogeneities. We show that the transition to boost-invariant flow occurs too late for realistic setups, with corrections of θ (20%-30%) expected at freeze-out for most scenarios. Moreover, the deviation from boost invariance is correlated with both transverse flow and elliptic flow, with the more highly transversely flowing regions also showing the most violation of boost invariance. Therefore, if longitudinal flow is not fully developed at the early stages of heavy ion collisions, hydrodynamics where boost invariance holds at midrapidity ismore » inadequate to extract transport coefficients of the quark-gluon plasma. We conclude by arguing that developing experimental probes of boost invariance is necessary, and suggest some promising directions in this regard.« less

A parametric study of the dynamic failure of energetic composites

NASA Astrophysics Data System (ADS)

Tanasoiu, Bogdan; Koslowski, Marisol

2017-09-01

Heating by frictional sliding of cracks is often considered to be one of the most important causes of localized melting and ignition in solid explosives. Furthermore, recent high speed X-ray phase contrast experiments on energetic composites under dynamic compression [Parab et al., Appl. Phys. Lett. 109(13) (2016)] show that most fracture events appear inside the particles. Initial cracks develop in regions where particles are close, and widespread fragmentation is observed in the interior of the particles as the stress waves propagate through the sample. However, most simulations have focused on interface debonding of energetic composites and, in general, do not include fracture of the particles explicitly. A phase field damage approach is used to model the dynamic response of a system of cyclotetramethylene-tetranitramine particles embedded in a Sylgard matrix. The simulations show several damage mechanisms observed in the experiments. The effects of the energy release rate and the initial crack distribution on the energy dissipation due to fracture are studied. The numerical results confirm that initial cracks play an important role in the evolution of damage, energy dissipation and consequently, the formation of hot-spots.

New insights into replication origin characteristics in metazoans

PubMed Central

Puy, Aurore; Rialle, Stéphanie; Kaplan, Noam; Segal, Eran

2012-01-01

We recently reported the identification and characterization of DNA replication origins (Oris) in metazoan cell lines. Here, we describe additional bioinformatic analyses showing that the previously identified GC-rich sequence elements form origin G-rich repeated elements (OGREs) that are present in 67% to 90% of the DNA replication origins from Drosophila to human cells, respectively. Our analyses also show that initiation of DNA synthesis takes place precisely at 160 bp (Drosophila) and 280 bp (mouse) from the OGRE. We also found that in most CpG islands, an OGRE is positioned in opposite orientation on each of the two DNA strands and detected two sites of initiation of DNA synthesis upstream or downstream of each OGRE. Conversely, Oris not associated with CpG islands have a single initiation site. OGRE density along chromosomes correlated with previously published replication timing data. Ori sequences centered on the OGRE are also predicted to have high intrinsic nucleosome occupancy. Finally, OGREs predict G-quadruplex structures at Oris that might be structural elements controlling the choice or activation of replication origins. PMID:22373526

Effect of water content and temperature on inactivation kinetics of myrosinase in broccoli (Brassica oleracea var. italica).

PubMed

Oliviero, T; Verkerk, R; Van Boekel, M A J S; Dekker, M

2014-11-15

Broccoli belongs to the Brassicaceae plant family consisting of widely eaten vegetables containing high concentrations of glucosinolates. Enzymatic hydrolysis of glucosinolates by endogenous myrosinase (MYR) can form isothiocyanates with health-promoting activities. The effect of water content (WC) and temperature on MYR inactivation in broccoli was investigated. Broccoli was freeze dried obtaining batches with WC between 10% and 90% (aw from 0.10 to 0.96). These samples were incubated for various times at different temperatures (40-70°C) and MYR activity was measured. The initial MYR inactivation rates were estimated by the first-order reaction kinetic model. MYR inactivation rate constants were lower in the driest samples (10% WC) at all studied temperatures. Samples with 67% and 90% WC showed initial inactivation rate constants all in the same order of magnitude. Samples with 31% WC showed intermediate initial inactivation rate constants. These results are useful to optimise the conditions of drying processes to produce dried broccoli with optimal MYR retention for human health. Copyright © 2014 Elsevier Ltd. All rights reserved.

Effects of activated aflatoxin B/sub 1/ and caffeine on DNA replicon initiation in HeLa cells

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

Cramer, P.; Painter, R.B.

1981-01-01

Afatoxin B/sub 1/ (AFB/sub 1/) is activated by a rat microsomal extract (S-9) to form a product that inhibits DNA synthesis in HeLa cells. At 10/sup -7/ M, AFB/sub 1/ inhibited initiation of replicons, as shown in alkaline sucrose gradient profiles 30 min after incubation with the drug. Ninety minutes later, the profile of treated cells was similar to that of control, but 4 h later there was another effect on replicon initiation. At 10/sup -6/ M, the inhibition of initiation was greater than at 10/sup -7/ M and increased progressively. Four hours after removal of the drug, the gradientmore » profile showed low amounts of radioactivity in all size classes of DNA. When cells were incubated in medium containing caffeine (2 mM) even as late as 60 min after incubation with AFB/sub 1/, the inhibition of replicon initiation was prevented. If caffeine was later removed from the medium, replicon initiation was then inhibited. At 10/sup -7/ M or 10/sup -6/ M, AFB/sub 1/ had little immediate effect on chain elongation, but at 10/sup -5/ M, the gradient profiles showed an accumulation of low molecular weight DNA molecules, with no radioactivity in the region of high molecular weight DNA, owing to a block to chain elongation; this was not affected by caffeine. These results suggest that AFB/sub 1/ induces damage that changes the fonformation of chromatin so that initiation of new replicons cannot occur; in the presence of caffeine this change does not occur and DNA replication is not inhibited.« less

A novel platform to study magnetized high-velocity collisionless shocks

DOE PAGES

Higginson, D. P.; Korneev, Ph; Béard, J.; ...

2014-12-13

An experimental platform to study the interaction of two colliding high-velocity (0.01–0.2c; 0.05–20 MeV) proton plasmas in a high strength (20 T) magnetic field is introduced. This platform aims to study the collision of magnetized plasmas accelerated via the Target-Normal-Sheath-Acceleration mechanism and initially separated by distances of a few hundred microns. The plasmas are accelerated from solid targets positioned inside a few cubic millimeter cavity located within a Helmholtz coil that provides up to 20 T magnetic fields. Various parameters of the plasmas at their interaction location are estimated. These show an interaction that is highly non-collisional, and that becomesmore » more and more dominated by the magnetic fields as time progresses (from 5 to 60 ps). Particle-in-cell simulations are used to reproduce the initial acceleration of the plasma both via simulations including the laser interaction and via simulations that start with preheated electrons (to save dramatically on computational expense). The benchmarking of such simulations with the experiment and with each other will be used to understand the physical interaction when a magnetic field is applied. In conclusion, the experimental density profile of the interacting plasmas is shown in the case without an applied magnetic magnetic field, so to show that without an applied field that the development of high-velocity shocks, as a result of particle-to-particle collisions, is not achievable in the configuration considered.« less

A novel platform to study magnetized high-velocity collisionless shocks

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

Higginson, D. P.; Korneev, Ph; Béard, J.

An experimental platform to study the interaction of two colliding high-velocity (0.01–0.2c; 0.05–20 MeV) proton plasmas in a high strength (20 T) magnetic field is introduced. This platform aims to study the collision of magnetized plasmas accelerated via the Target-Normal-Sheath-Acceleration mechanism and initially separated by distances of a few hundred microns. The plasmas are accelerated from solid targets positioned inside a few cubic millimeter cavity located within a Helmholtz coil that provides up to 20 T magnetic fields. Various parameters of the plasmas at their interaction location are estimated. These show an interaction that is highly non-collisional, and that becomesmore » more and more dominated by the magnetic fields as time progresses (from 5 to 60 ps). Particle-in-cell simulations are used to reproduce the initial acceleration of the plasma both via simulations including the laser interaction and via simulations that start with preheated electrons (to save dramatically on computational expense). The benchmarking of such simulations with the experiment and with each other will be used to understand the physical interaction when a magnetic field is applied. In conclusion, the experimental density profile of the interacting plasmas is shown in the case without an applied magnetic magnetic field, so to show that without an applied field that the development of high-velocity shocks, as a result of particle-to-particle collisions, is not achievable in the configuration considered.« less

Low-Cycle Fatigue Behavior of 10CrNi3MoV High Strength Steel and Its Undermatched Welds

PubMed Central

Liu, Xuesong; Berto, Filippo

2018-01-01

The use of high strength steel allows the design of lighter, more slender and simpler structures due to high strength and favorable ductility. Nevertheless, the increase of yield strength does not guarantee the corresponding improvement of fatigue resistance, which becomes a major concern for engineering structure design, especially for the welded joints. The paper presents a comparison of the low cycle fatigue behaviors between 10CrNi3MoV high strength steel and its undermatched weldments. Uniaxial tension tests, Push-pull, strain-controlled fatigue tests were conducted on base metal and weldments in the strain range of 0.2–1.2%. The monotonic and cyclic stress-strain curves, stress-life, strain-life and energy-life in terms of these materials were analyzed for fatigue assessment of materials discrepancy. The stress-life results of base metal and undermatched weld metal exhibit cyclic softening behaviors. Furthermore, the shapes of 10CrNi3MoV steel hysteresis loops show a satisfactory Masing-type behavior, while the weld metal shows a non-Masing type behavior. Strain, plastic and total strain energy density amplitudes against the number of reversals to failure results demonstrate that the undermatched weld metal presents a higher resistance to fatigue crack initiation than 10CrNi3MoV high strength steel. Finally, fatigue fracture surfaces of specimens were compared by scanning electron microscopy to identify the differences of crack initiation and the propagation between them. PMID:29695140

Low-Cycle Fatigue Behavior of 10CrNi3MoV High Strength Steel and Its Undermatched Welds.

PubMed

Song, Wei; Liu, Xuesong; Berto, Filippo; Razavi, S M J

2018-04-24

The use of high strength steel allows the design of lighter, more slender and simpler structures due to high strength and favorable ductility. Nevertheless, the increase of yield strength does not guarantee the corresponding improvement of fatigue resistance, which becomes a major concern for engineering structure design, especially for the welded joints. The paper presents a comparison of the low cycle fatigue behaviors between 10CrNi3MoV high strength steel and its undermatched weldments. Uniaxial tension tests, Push-pull, strain-controlled fatigue tests were conducted on base metal and weldments in the strain range of 0.2⁻1.2%. The monotonic and cyclic stress-strain curves, stress-life, strain-life and energy-life in terms of these materials were analyzed for fatigue assessment of materials discrepancy. The stress-life results of base metal and undermatched weld metal exhibit cyclic softening behaviors. Furthermore, the shapes of 10CrNi3MoV steel hysteresis loops show a satisfactory Masing-type behavior, while the weld metal shows a non-Masing type behavior. Strain, plastic and total strain energy density amplitudes against the number of reversals to failure results demonstrate that the undermatched weld metal presents a higher resistance to fatigue crack initiation than 10CrNi3MoV high strength steel. Finally, fatigue fracture surfaces of specimens were compared by scanning electron microscopy to identify the differences of crack initiation and the propagation between them.

Charcoal in organic horizon and surface mineral soil in a boreal forest postfire chronosequence of Western Quebec: stocks, depth distribution, chemical properties and a synthesis of related studies

NASA Astrophysics Data System (ADS)

Preston, Caroline M.; Simard, Martin; Bergeron, Yves; Bernard, Guy M.; Wasylishen, Roderick E.

2017-11-01

Wildfires are a major driver of carbon stocks and ecosystem development in Canadian boreal forests, but there is little information on amounts and properties of the charcoal produced. Using data and samples available from a previous study, we determined amounts, depth distribution and chemical properties of visually-determined charcoal (> 2 mm) in a boreal chronosequence in the Abitibi region of Quebec, Canada. Sites ranged from 24 to 2355 years since fire (ysf) and originated from low- and high-severity soil burns (> 5 cm or < 5 cm organic horizon unburned, respectively). Two or three pits were sampled at 1-cm depth intervals from 20 jack pine (Pinus banksiana) sites (one low severity and 19 high severity) and 31 black spruce (Picea mariana) sites (12 low severity and 19 high severity). Site-level charcoal stocks ranged from 50 to 5527 kg ha-1 with high within-site variability and lower stocks for the oldest sites. Depth distributions typically peaked around the organic-mineral interface, but some low-severity sites also had charcoal layers within the organic horizon. Means from 30 samples were 569 mg g-1 total C, 4.1 mg g-1 total N and 140 C/N (molar), with total C and C/N showing a trend of decline with time since fire, and total N showing an increase. Solid-state 13C CPMAS NMR spectra of nine samples showed high variability among the younger samples, but a trend to higher aromaticity for the older ones. A literature survey focusing on boreal forests similarly showed highly variable stocks and chemical properties of charcoal in organic horizon and upper mineral soil, with reduction of variance and lower stocks after several hundred years. This initial variation was also consistent with reports of highly variable temperatures and duration of charring in wildfires. Adding reports available for char production, and considering that most studies of char stocks and production are limited to the organic horizon (forest floor), suggests that initial production of charred material from boreal wildfires might be around 5-10 tonnes ha-1.

What if Reading is Easy but Unimportant? How Students’ Patterns of Affirming and Undermining Motivation for Reading Information Texts Predict Different Reading Outcomes

PubMed Central

Rosenzweig, Emily Q.; Wigfield, Allan

2016-01-01

Many affirming and undermining motivational constructs affect students as they read information texts, but few researchers have explored how these motivations are patterned within students. In this study we used cluster analysis to classify middle school students (n = 1,134) based on their patterns of self-efficacy, perceived difficulty, value, and devalue for reading school information texts. We then compared how the patterns predicted students’ language arts grades, science information text comprehension, and dedication to reading school information texts. We found and validated a four-cluster solution. One cluster included a pattern of high affirming and low undermining motivations, and another included low affirming and high undermining motivations. Students with these patterns earned the highest and lowest scores, respectively, on all outcomes. A third pattern showed high self-efficacy/low difficulty with low value/high devalue, and a fourth showed moderate levels of all four motivational constructs. Students with the high efficacy and devalue pattern showed high information text comprehension but relatively low dedication. Students with the moderate pattern showed high dedication but low initial information text comprehension. Students with these two patterns earned similar grades. We discuss the implications of our findings for motivation theories and for school instruction that involves information text reading. PMID:28496289

What if Reading is Easy but Unimportant? How Students' Patterns of Affirming and Undermining Motivation for Reading Information Texts Predict Different Reading Outcomes.

PubMed

Rosenzweig, Emily Q; Wigfield, Allan

2017-01-01

Many affirming and undermining motivational constructs affect students as they read information texts, but few researchers have explored how these motivations are patterned within students. In this study we used cluster analysis to classify middle school students (n = 1,134) based on their patterns of self-efficacy, perceived difficulty, value, and devalue for reading school information texts. We then compared how the patterns predicted students' language arts grades, science information text comprehension, and dedication to reading school information texts. We found and validated a four-cluster solution. One cluster included a pattern of high affirming and low undermining motivations, and another included low affirming and high undermining motivations. Students with these patterns earned the highest and lowest scores, respectively, on all outcomes. A third pattern showed high self-efficacy/low difficulty with low value/high devalue, and a fourth showed moderate levels of all four motivational constructs. Students with the high efficacy and devalue pattern showed high information text comprehension but relatively low dedication. Students with the moderate pattern showed high dedication but low initial information text comprehension. Students with these two patterns earned similar grades. We discuss the implications of our findings for motivation theories and for school instruction that involves information text reading.

Expression of the Eukaryotic Translation Initiation Factors 4E and 2α in Non-Hodgkin’s Lymphomas

PubMed Central

Wang, Songtao; Rosenwald, Igor B.; Hutzler, Michael J.; Pihan, German A.; Savas, Lou; Chen, Jane-Jane; Woda, Bruce A.

1999-01-01

Transition of cells from quiescence to proliferation requires an increase in the rate of protein synthesis, which is regulated in part by two key translation initiation factors, 4E and 2α. The expression and activity of both factors are increased transiently when normal resting cells are stimulated to proliferate. They are constitutively elevated in oncogene transformed cultured cells, and overexpression of either initiation factor in rodent cells makes them tumorigenic. In this study we investigate an association between the expression of translation initiation factors and lymphomagenesis. We have analyzed the expression of the protein synthesis initiation factors 4E and 2α by immunohistochemistry in reactive lymph nodes and several types of non-Hodgkin’s lymphoma representing a wide range of clinical behaviors based on the Revised European-American Lymphoma behavioral classification. The study included 7 benign lymph nodes with follicular hyperplasia, 26 indolent lymphomas (6 marginal zone lymphomas, 7 small lymphocytic lymphomas, and 13 follicular lymphomas, grades 1 and 2), 16 moderately aggressive lymphomas (8 mantle cell lymphomas and 8 follicular lymphomas, grade 3), 24 aggressive lymphomas (14 large-B-cell lymphomas and 10 anaplastic large-cell lymphomas), and 15 highly aggressive lymphomas (7 lymphoblastic lymphomas and 8 Burkitt’s lymphomas). Strong expression of initiation factors 4E and 2α was demonstrated in the germinal centers of reactive follicles. Minimal or no expression was seen in the mantle zones and surrounding paracortices, indicating that high expression of initiation factors 4E and 2α is associated with the active proliferation of lymphocytes. Most cases of aggressive and highly aggressive lymphomas showed strong expression of initiation factors 4E and 2α, in contrast to the cases of indolent and moderately aggressive lymphoma, in which their expression was intermediate between the germinal centers and the mantles of reactive follicles. A positive correlation was found between the expression of both initiation factors 4E and 2α and the Revised European-American Lymphoma behavior classification (P < 0.05). Thus, constitutively increased expression of initiation factors 4E and 2α may play an important role in the development of lymphomas and is correlated with their biological aggressiveness. PMID:10393856

Preclinical Evaluation of 18F-JNJ64349311, a Novel PET Tracer for Tau Imaging.

PubMed

Declercq, Lieven; Rombouts, Frederik; Koole, Michel; Fierens, Katleen; Mariën, Jonas; Langlois, Xavier; Andrés, José Ignacio; Schmidt, Mark; Macdonald, Gregor; Moechars, Diederik; Vanduffel, Wim; Tousseyn, Thomas; Vandenberghe, Rik; Van Laere, Koen; Verbruggen, Alfons; Bormans, Guy

2017-06-01

In this study, we have synthesized and evaluated 18 F-JNJ64349311, a tracer with high affinity for aggregated tau (inhibition constant value, 8 nM) and high (≥500×) in vitro selectivity for tau over β-amyloid, in comparison with the benchmark compound 18 F-AV1451 ( 18 F-T807) in mice, rats, and a rhesus monkey. Methods: In vitro binding characteristics were determined for Alzheimer's disease, progressive supranuclear palsy, and corticobasal degeneration patient brain tissue slices using autoradiography studies. Ex vivo biodistribution studies were performed in mice. Radiometabolites were quantified in the brain and plasma of mice and in the plasma of a rhesus monkey using high-performance liquid chromatography. Dynamic small-animal PET studies were performed in rats and a rhesus monkey to evaluate tracer pharmacokinetics in the brain. Results: Mouse biodistribution studies showed moderate initial brain uptake and rapid brain washout. Radiometabolite analyses after injection of 18 F-JNJ64349311 in mice showed the presence of a polar radiometabolite in plasma, but not in the brain. Semiquantitative autoradiography studies on postmortem tissue sections of human Alzheimer's disease brains showed highly displaceable binding to tau-rich regions. No specific binding was, however, found on human progressive supranuclear palsy and corticobasal degeneration brain slices. Small-animal PET scans of Wistar rats revealed moderate initial brain uptake (SUV, ∼1.5 at 1 min after injection) and rapid brain washout. Gradual bone uptake was, however, also observed. Blocking and displacement did not affect brain time-activity curves, suggesting no off-target specific binding of the tracer in the healthy rat brain. A small-animal PET scan of a rhesus monkey revealed moderate initial brain uptake (SUV, 1.9 at 1 min after injection) with a rapid washout. In the monkey, no bone uptake was detected during the 120-min scan. Conclusion: This biologic evaluation suggests that 18 F-JNJ64349311 is a promising tau PET tracer candidate, with a favorable pharmacokinetic profile, as compared with 18 F-AV1451. © 2017 by the Society of Nuclear Medicine and Molecular Imaging.

Alpha chymotrypsin coated clusters of Fe3O4 nanoparticles for biocatalysis in low water media.

PubMed

Mukherjee, Joyeeta; Gupta, Munishwar N

2012-11-08

Enzymes in low water containing non aqueous media are useful for organic synthesis. For example, hydrolases in such media can be used for synthetic purposes. Initial work in this area was carried out with lyophilized powders of enzymes. These were found to have poor activity. Drying (removing bulk water) by precipitation turned out to be a better approach. As enzymes in such media are heterogeneous catalysts, spreading these precipitates over a large surface gave even better results. In this context, nanoparticles with their better surface to volume ratio provide obvious advantage. Magnetic nanoparticles have an added advantage of easy separation after the reaction. Keeping this in view, alpha chymotrypsin solution in water was precipitated over a stirred population of Fe3O4 nanoparticles in n-propanol. This led to alpha chymotrypsin activity coated over clusters of Fe3O4 nanoparticles. These preparations were found to have quite high transesterification activity in low water containing n-octane. Precipitation of alpha chymotrypsin over a stirred suspension of Fe3O4 nanoparticles (3.6 nm diameter) led to the formation of enzyme coated clusters of nanoparticles (ECCNs). These clusters were also magnetic and their hydrodynamic diameter ranged from 1.2- 2.6 microns (as measured by dynamic light scattering). Transmission electron microscopy (TEM), showed that these clusters had highly irregular shapes. Transesterification assay of various clusters in anhydrous n-octane led to optimization of concentration of nanoparticles in suspension during precipitation. Optimized design of enzyme coated magnetic clusters of nanoparticles (ECCN 3) showed the highest initial rate of 465 nmol min-1 mg-1protein which was about 9 times higher as compared to the simple precipitates with an initial rate of 52 nmol min-1 mg-1 protein.Circular Dichroism (CD)(with a spinning cell accessory) showed that secondary structure content of the alpha Chymotrypsin in ECCN 3 [15% α-helix, 37% β-sheet and 48% random coil] was identical to the simple precipitates of alpha chymotrypsin. A strategy for obtaining a high activity preparation of alpha chymotrypsin for application in low water media is described. Such high activity biocatalysts are useful in organic synthesis.

[Clinical, epidemiological, and etiological studies of adult aseptic meningitis: a report of 12 cases of herpes simplex meningitis, and a comparison with cases of herpes simplex encephalitis].

PubMed

Himeno, Takahiro; Shiga, Yuji; Takeshima, Shinichi; Tachiyama, Keisuke; Kamimura, Teppei; Kono, Ryuhei; Takemaru, Makoto; Takeshita, Jun; Shimoe, Yutaka; Kuriyama, Masaru

2018-01-26

We treated 437 cases of adult aseptic meningitis and 12 cases (including 2 recurrent patients; age, 31.8 ± 8.9 years; 7 females) of herpes simplex meningitis from 2004 to 2016. The incidence rate of adult herpes simplex meningitis in the cases with aseptic meningitis was 2.7%. One patient was admitted during treatment of genital herpes, but no association was observed between genital herpes and herpes simplex meningitis in the other cases. The diagnoses were confirmed in all cases as the cerebrospinal fluid (CSF) was positive for herpes simplex virus (HSV)-DNA. For diagnosis confirmation, the DNA test was useful after 2-7 days following initial disease onset. Among other types of aseptic meningitis, the patients with herpes simplex meningitis showed relatively high white blood cell counts and relatively high CSF protein and high CSF cell counts. CSF cells showed mononuclear cell dominance from the initial stage of the disease. During same period, we also experienced 12 cases of herpes simplex encephalitis and 21 cases of non-hepatic acute limbic encephalitis. Notably, the patients with herpes simplex meningitis were younger and their CSF protein and cells counts were higher than those of the patients with herpes simplex encephalitis.

Degradation of trichloroethylene in aqueous solution by calcium peroxide activated with ferrous ion.

PubMed

Zhang, Xiang; Gu, Xiaogang; Lu, Shuguang; Miao, Zhouwei; Xu, Minhui; Fu, Xiaori; Qiu, Zhaofu; Sui, Qian

2015-03-02

The application of calcium peroxide (CaO2) activated with ferrous ion to stimulate the degradation of trichloroethylene (TCE) was investigated. The experimental results showed that TCE could be completely degraded in 5 min at a CaO2/Fe(II)/TCE molar ratio of 4/8/1. Probe compound tests demonstrated the presence of reactive oxygen species HO· and O2(-·) in CaO2/Fe(II) system, while scavenging tests indicated that HO· was the dominant active species responsible for TCE removal, and O2(-·) could promote TCE degradation in CaO2/Fe(II) system. In addition, the influences of initial solution pH and solution matrix were evaluated. It suggested that the elevation of initial solution pH suppressed TCE degradation. Cl(-) had significant scavenging effect on TCE removal, whereas HCO3(-) of high concentration showed favorable function. The influences of NO3(-) and SO4(2-) could be negligible, while natural organic matter (NOM) had a negative effect on TCE removal at a relatively high concentration. The results demonstrated that the technique of CaO2 activated with ferrous ion is a highly promising technique in in situ chemical oxidation (ISCO) remediation in TCE contaminated sites. Copyright © 2014. Published by Elsevier B.V.

3D numerical study of the propagation characteristics of a consequence of coronal mass ejections in a structured ambient solar wind

NASA Astrophysics Data System (ADS)

Zhou, Y.; Feng, X. S.

2015-12-01

CMEs have been identified as a prime causal link between solar activity and large, nonrecurrent geomagnetic storm. In order to improve geomagnetic storm predictions, a careful study of CME's propagation characteristics is important. Here, we analyze and quantitatively study the evolution and propagation characteristics of coronal mass ejections (CMEs) launched at several positions into a structured real ambient solar wind by using a three-dimensional (3D) numerical magnetohydrodynamics (MHD) simulation. The ambient solar wind structure during Carrington rotation 2095 is selected, which is an appropriate around activity minimum and declining phase. The CME is initiated by a simple spherical plasmoid model: a spheromak magnetic structure with high speed, high pressure and high plasma density plasmoid. We present a detailed analysis of the plasma, magnetic field, geoeffectiveness, and composition signatures of these CMEs. Results show that the motion and local appearance of a CME in interplanetary space is strongly affected by its interaction with the background solar wind structure, including its velocity, density, and magnetic structures. The simulations show that the initial launched position substantially affects the IP evolution of the CMEs influencing the propagation velocity, the shape, the trajectory and even the geo-effectiveness

A 67-Item Stress Resilience item bank showing high content validity was developed in a psychosomatic sample.

PubMed

Obbarius, Nina; Fischer, Felix; Obbarius, Alexander; Nolte, Sandra; Liegl, Gregor; Rose, Matthias

2018-04-10

To develop the first item bank to measure Stress Resilience (SR) in clinical populations. Qualitative item development resulted in an initial pool of 131 items covering a broad theoretical SR concept. These items were tested in n=521 patients at a psychosomatic outpatient clinic. Exploratory and Confirmatory Factor Analysis (CFA), as well as other state-of-the-art item analyses and IRT were used for item evaluation and calibration of the final item bank. Out of the initial item pool of 131 items, we excluded 64 items (54 factor loading <.5, 4 residual correlations >.3, 2 non-discriminative Item Response Curves, 4 Differential Item Functioning). The final set of 67 items indicated sufficient model fit in CFA and IRT analyses. Additionally, a 10-item short form with high measurement precision (SE≤.32 in a theta range between -1.8 and +1.5) was derived. Both the SR item bank and the SR short form were highly correlated with an existing static legacy tool (Connor-Davidson Resilience Scale). The final SR item bank and 10-item short form showed good psychometric properties. When further validated, they will be ready to be used within a framework of Computer-Adaptive Tests for a comprehensive assessment of the Stress-Construct. Copyright © 2018. Published by Elsevier Inc.

Predictors of outcome of an Internet-based cognitive-behavioural therapy for post-traumatic stress disorder in older adults.

PubMed

Böttche, Maria; Kuwert, Philipp; Pietrzak, Robert H; Knaevelsrud, Christine

2016-03-01

The aim of this study was to evaluate the role of resource-oriented variables such as self-efficacy, locus of control (LOC) and post-traumatic growth (PTG) in predicting treatment response in older adults with post-traumatic stress. Fifty-eight older adults with subsyndromal or greater severity of war-associated post-traumatic stress disorder (PTSD) symptoms completed a randomized controlled Internet-based cognitive-behavioural therapy (CBT) with immediate and delayed treatment groups. Assessments of PTSD severity and resource-oriented variables of self-efficacy, LOC and PTG were conducted at baseline, post-treatment and at a 6-month follow-up. Results revealed that pre-treatment scores on measures of internal LOC and PTG predicted PTSD symptom severity at post-treatment, even after controlling for initial PTSD. At a 6-month follow-up, internal LOC continued to predict PTSD symptom severity. In addition, repeated-measures analyses of variance revealed that, relative to older adults with low internal LOC and PTG, older adults with high internal LOC and PTG, respectively, did not differ with respect to initial PTSD severity, but they showed a more pronounced response to treatment. These findings suggest that greater locus of control and post-traumatic growth is associated with greater improvement in PTSD symptoms following Internet-based CBT. Assessment of these constructs may be useful in identifying trauma survivors who are most likely to respond to CBT. Greater internal locus of control and post-traumatic growth is associated with greater improvement in PTSD symptoms following Internet-based CBT. Older adults with initial high internal locus of control and post-traumatic growth, respectively, did not differ with respect to initial PTSD severity, but they showed a more pronounced response to treatment. It could be assumed that patients with initial functional appraisals could benefit easier and faster from a trauma-focused cognitive-behavioural therapy compared to individuals with lower internal locus of control and post-traumatic growth. © 2015 The British Psychological Society.

[Recovery in aphasia (Part 1)].

PubMed

Hojo, K; Watanabe, S; Tasaki, H; Sato, T; Metoki, H; Saito, M

1985-08-01

In order to elucidate the factors which have an influence on the prognosis of aphasia, a correlation was studied in 76 right-handed aphasic patients between recovery rates and various factors: i.e. aphasia type, age, educational level, time between onset of aphasia and institution of therapy and initial severity. Initial evaluations on Standard Language Test of Aphasia (SLTA) were obtained within 5 months after the cerebrovascular accident and reevaluations were obtained 3 months after the initial evaluation. Recovery rates were determined by comparing scores of these 2 tests in order to coincide with clinical impression. The results obtained were as follows: Aphasia type: The highest recovery rates were seen in conduction aphasics, followed by amnestic, Wernicke, and Broca aphasics. Global aphasics had significantly lower recovery rates. It was suggested that anarthria in Broca's aphasia and jargon in Wernicke's aphasia had a significant ratarding effect on recovery rates. Age: Age and recovery rates showed a significant negative correlation: younger patients recovered better, and this trend was remarkable in Wernicke aphasics but not Broca aphasics. Education: Patients with more education tended to improve more, and this trend was most remarkable in amnestic aphasics. Time between onset of aphasia and institution of therapy: Time elapsed from onset and recovery rates showed a significant negative correlation; recovery rates decreased as the time interval from onset increased. Initial severity: Correlation between the initial severity of aphasia, measured by the initial SLTA scores and recovery rates was very high; severily affected aphasics recovered to a lesser extent than mildly affected ones and this trend was remarkable in Wernicke and Broca aphasics.

A Comparative Study of Interval Management Control Law Capabilities

NASA Technical Reports Server (NTRS)

Barmore, Bryan E.; Smith, Colin L.; Palmer, Susan O.; Abbott, Terence S.

2012-01-01

This paper presents a new tool designed to allow for rapid development and testing of different control algorithms for airborne spacing. This tool, Interval Management Modeling and Spacing Tool (IM MAST), is a fast-time, low-fidelity tool created to model the approach of aircraft to a runway, with a focus on their interactions with each other. Errors can be induced between pairs of aircraft by varying initial positions, winds, speed profiles, and altitude profiles. Results to-date show that only a few of the algorithms tested had poor behavior in the arrival and approach environment. The majority of the algorithms showed only minimal variation in performance under the test conditions. Trajectory-based algorithms showed high susceptibility to wind forecast errors, while performing marginally better than the other algorithms under other conditions. Trajectory-based algorithms have a sizable advantage, however, of being able to perform relative spacing operations between aircraft on different arrival routes and flight profiles without employing ghosting. methods. This comes at the higher cost of substantially increased complexity, however. Additionally, it was shown that earlier initiation of relative spacing operations provided more time for corrections to be made without any significant problems in the spacing operation itself. Initiating spacing farther out, however, would require more of the aircraft to begin spacing before they merge onto a common route.

Brain volume reductions in adolescent heavy drinkers.

PubMed

Squeglia, Lindsay M; Rinker, Daniel A; Bartsch, Hauke; Castro, Norma; Chung, Yoonho; Dale, Anders M; Jernigan, Terry L; Tapert, Susan F

2014-07-01

Brain abnormalities in adolescent heavy drinkers may result from alcohol exposure, or stem from pre-existing neural features. This longitudinal morphometric study investigated 40 healthy adolescents, ages 12-17 at study entry, half of whom (n=20) initiated heavy drinking over the 3-year follow-up. Both assessments included high-resolution magnetic resonance imaging. FreeSurfer was used to segment brain volumes, which were measured longitudinally using the newly developed quantitative anatomic regional change analysis (QUARC) tool. At baseline, participants who later transitioned into heavy drinking showed smaller left cingulate, pars triangularis, and rostral anterior cingulate volume, and less right cerebellar white matter volumes (p<.05), compared to continuous non-using teens. Over time, participants who initiated heavy drinking showed significantly greater volume reduction in the left ventral diencephalon, left inferior and middle temporal gyrus, and left caudate and brain stem, compared to substance-naïve youth (p<.05). Findings suggest pre-existing volume differences in frontal brain regions in future drinkers and greater brain volume reduction in subcortical and temporal regions after alcohol use was initiated. This is consistent with literature showing pre-existing cognitive deficits on tasks recruited by frontal regions, as well as post-drinking consequences on brain regions involved in language and spatial tasks. Published by Elsevier Ltd.

Degradation of bromamine acid by nanoscale zero-valent iron (nZVI) supported on sepiolite.

PubMed

Fei, Xuening; Cao, Lingyun; Zhou, Lifeng; Gu, Yingchun; Wang, Xiaoyang

2012-01-01

Sepiolite, a natural nano-material, was chosen as a carrier to prepare supported nanoscale zero-valent iron (nZVI). The effects of preparation conditions, including mass ratio of nZVI and activated sepiolite and preparation pH value, on properties of the supported nZVI were investigated. The results showed that the optimal mass ratio of nZVI and sepiolite was 1.12:1 and the optimal pH value was 7. The supported nZVI was characterized by X-ray diffraction (XRD), transmission electron microscope (TEM) and energy dispersive spectrometer (EDS), and furthermore an analogy model of the supported nZVI was set up. Compared with the nZVI itself, the supported nZVI was more stable in air and possessed better water dispersibility, which were beneficial for the degradation of bromamine acid aqueous solution. The degradation characteristics, such as effects of supported nZVI dosage, initial concentration and initial pH value of the solution on the decolorization efficiency were also investigated. The results showed that in an acidic environment the supported nZVI with a dosage of 2 g/L showed high activity in the degradation of bromamine acid with an initial concentration of 1,000 mg/L, and the degree of decolorization could reach up to 98%.

Wang-Landau sampling: Saving CPU time

NASA Astrophysics Data System (ADS)

Ferreira, L. S.; Jorge, L. N.; Leão, S. A.; Caparica, A. A.

2018-04-01

In this work we propose an improvement to the Wang-Landau (WL) method that allows an economy in CPU time of about 60% leading to the same results with the same accuracy. We used the 2D Ising model to show that one can initiate all WL simulations using the outputs of an advanced WL level from a previous simulation. We showed that up to the seventh WL level (f6) the simulations are not biased yet and can proceed to any value that the simulation from the very beginning would reach. As a result the initial WL levels can be simulated just once. It was also observed that the saving in CPU time is larger for larger lattice sizes, exactly where the computational cost is considerable. We carried out high-resolution simulations beginning initially from the first WL level (f0) and another beginning from the eighth WL level (f7) using all the data at the end of the previous level and showed that the results for the critical temperature Tc and the critical static exponents β and γ coincide within the error bars. Finally we applied the same procedure to the 1/2-spin Baxter-Wu model and the economy in CPU time was of about 64%.

Virtual reality bringing a new reality to postthoracotomy lung cancer patients via a home-based exercise intervention targeting fatigue while undergoing adjuvant treatment.

PubMed

Hoffman, Amy J; Brintnall, Ruth Ann; Brown, Jean K; von Eye, Alexander; Jones, Lee W; Alderink, Gordon; Ritz-Holland, Deborah; Enter, Mark; Patzelt, Lawrence H; VanOtteren, Glenn M

2014-01-01

Little is known about rehabilitation for postthoracotomy non-small cell lung cancer (NSCLC) patients. This research uses a perceived self-efficacy-enhancing light-intensity exercise intervention targeting a priority symptom, cancer-related fatigue (CRF), for postthoracotomy NSCLC patients. This article reports on phase II of a 2-phase study. Phase I focused on initiation and tolerance of exercise during the 6 weeks immediately after thoracotomy, whereas phase II addressed maintenance of exercise for an additional 10 weeks including participants initiating and completing chemotherapy and/or radiation therapy. The objective of this study was to investigate the feasibility, acceptability, and preliminary efficacy of an exercise intervention for postthoracotomy NSCLC patients to include those initiating and completing adjuvant therapy. A single-arm design composed of 7 participants postthoracotomy for NSCLC performed light-intensity exercises using an efficacy-enhancing virtual-reality approach using the Nintendo Wii Fit Plus. Despite most participants undergoing chemotherapy and/or radiation therapy, participants adhered to the intervention at a rate of 88% with no adverse events while giving the intervention high acceptability scores on conclusion. Likewise, participants' CRF scores improved from initiation through the conclusion of the intervention with perceived self-efficacy for walking at a light intensity continuously for 60 minutes, improving significantly upon conclusion over presurgery values. Postthoracotomy NSCLC patients maintained exercise for an additional 10 weeks while undergoing adjuvant therapy showing rehabilitation potential because the exercise intervention was feasible, safe, well tolerated, and highly acceptable showing positive changes in CRF self-management. A randomized controlled trial is needed to further investigate these relationships.

Forward genetics defines Xylt1 as a key, conserved regulator of early chondrocyte maturation and skeletal length.

PubMed

Mis, Emily K; Liem, Karel F; Kong, Yong; Schwartz, Nancy B; Domowicz, Miriam; Weatherbee, Scott D

2014-01-01

The long bones of the vertebrate body are built by the initial formation of a cartilage template that is later replaced by mineralized bone. The proliferation and maturation of the skeletal precursor cells (chondrocytes) within the cartilage template and their replacement by bone is a highly coordinated process which, if misregulated, can lead to a number of defects including dwarfism and other skeletal deformities. This is exemplified by the fact that abnormal bone development is one of the most common types of human birth defects. Yet, many of the factors that initiate and regulate chondrocyte maturation are not known. We identified a recessive dwarf mouse mutant (pug) from an N-ethyl-N-nitrosourea (ENU) mutagenesis screen. pug mutant skeletal elements are patterned normally during development, but display a ~20% length reduction compared to wild-type embryos. We show that the pug mutation does not lead to changes in chondrocyte proliferation but instead promotes premature maturation and early ossification, which ultimately leads to disproportionate dwarfism. Using sequence capture and high-throughput sequencing, we identified a missense mutation in the Xylosyltransferase 1 (Xylt1) gene in pug mutants. Xylosyltransferases catalyze the initial step in glycosaminoglycan (GAG) chain addition to proteoglycan core proteins, and these modifications are essential for normal proteoglycan function. We show that the pug mutation disrupts Xylt1 activity and subcellular localization, leading to a reduction in GAG chains in pug mutants. The pug mutant serves as a novel model for mammalian dwarfism and identifies a key role for proteoglycan modification in the initiation of chondrocyte maturation. © 2013 Published by Elsevier Inc.

Interacting shells in AdS spacetime and chaos

NASA Astrophysics Data System (ADS)

Brito, Richard; Cardoso, Vitor; Rocha, Jorge V.

2016-07-01

We study the simplest two-body problem in asymptotically anti-de Sitter spacetime: two, infinitely thin, concentric spherical shells of matter. We include only gravitational interaction between the two shells, but we show that the dynamics of this system is highly nontrivial. We observe prompt collapse to a black hole, delayed collapse and even perpetual oscillatory motion, depending on the initial location of the shells (or their energy content). The system exhibits critical behavior, and we show strong hints that it is also chaotic.

Selective, ultrathin membrane skins prepared by deposition of novel polymer films on porous alumina supports

NASA Astrophysics Data System (ADS)

Balachandra, Anagi Manjula

Membrane-based separations are attractive in industrial processes because of their low energy costs and simple operation. However, low permeabilities often make membrane processes uneconomical. Since flux is inversely proportional to membrane thickness, composite membranes consisting of ultrathin, selective skins on highly permeable supports are required to simultaneously achieve high throughput and high selectivity. However, the synthesis of defect-free skins with thicknesses less than 50 nm is difficult, and thus flux is often limited. Layer-by-layer deposition of oppositely charged polyelectrolytes on porous supports is an attractive method to synthesize ultrathin ion-separation membranes with high flux and high selectivity. The ion-transport selectivity of multilayer polyelectrolyte membranes (MPMs) is primarily due to Donnan exclusion; therefore increase in fixed charge density should yield high selectivity. However, control over charge density in MPMs is difficult because charges on polycations are electrostatically compensated by charges on polyanions, and the net charge in the bulk of these films is small. To overcome this problem, we introduced a templating method to create ion-exchange sites in the bulk of the membrane. This strategy involves alternating deposition of a Cu2+-poly(acrylic acid) complex and poly(allylamine hydrochloride) on a porous alumina support followed by removal of Cu2+ and deprotonation to yield free -COO- ion-exchange sites. Diffusion dialysis studies showed that the Cl-/SO42-. Selectivity of Cu2+-templated membranes is 4-fold higher than that of membranes prepared in the absence of Cu2+. Post-deposition cross-linking of these membranes by heat-induced amide bond formation further increased Cl-/SO42- selectivity to values as high as 600. Room-temperature, surface-initiated atom transfer radical polymerization (ATRP) provides another convenient method for formation of ultrathin polymer skins. This process involves attachment of polymerization initiators to a porous alumina support and subsequent polymerization from these initiators. Because ATRP is a controlled polymerization technique, it yields well-defined polymer films with low polydispersity indices (narrow molecular weight distributions). Additionally, this method is attractive because film thickness can be easily controlled by adjusting polymerization time. Gas-permeability data showed that grafted poly(ethylene glycol dimethacrylate) membranes have a CO 2/CH4 selectivity of 20, whereas poly(2-hydroxyethyl methacrylate) (PHEMA) films grown from a surface have negligible selectivity. However, derivatization of PHEMA with pentadecafluorooctanoyl chloride increases the solubility of CO2 in the membrane and results in a CO2/CH4 selectivity of 9. Although composite PHEMA membranes have no significant gas-transport selectivity, diffusion dialysis studies with PHEMA membranes showed moderate ion-transport selectivities. Cross-linking of PHEMA membranes by reaction with succinyl chloride greatly enhanced anion-transport selectivities while maintaining reasonable flux. The selectivities of these systems demonstrate that alternating polyelectrolyte deposition and surface-initiated ATRP are indeed capable of forming ultrathin, defect-free membrane skins that can potentially be modified for specific separations.

High-Fidelity Rapid Initialization and Read-Out of an Electron Spin via the Single Donor D(-) Charge State.

PubMed

Watson, T F; Weber, B; House, M G; Büch, H; Simmons, M Y

2015-10-16

We demonstrate high-fidelity electron spin read-out of a precision placed single donor in silicon via spin selective tunneling to either the D(+) or D(-) charge state of the donor. By performing read-out at the stable two electron D(0)↔D(-) charge transition we can increase the tunnel rates to a nearby single electron transistor charge sensor by nearly 2 orders of magnitude, allowing faster qubit read-out (1 ms) with minimum loss in read-out fidelity (98.4%) compared to read-out at the D(+)↔D(0) transition (99.6%). Furthermore, we show that read-out via the D(-) charge state can be used to rapidly initialize the electron spin qubit in its ground state with a fidelity of F(I)=99.8%.

Obesity Prevention in the Nordic Countries.

PubMed

Stockmarr, Anders; Hejgaard, Tatjana; Matthiessen, Jeppe

2016-06-01

Previous studies have shown that mean BMI and prevalences of overweight/obesity and obesity have increased over the last decades in the Nordic countries, despite highly regulated societies with a focus on obesity prevention. We review recent overweight/obesity and obesity prevention initiatives within four of the five Nordic countries: Sweden, Denmark, Finland, and Iceland. Moreover, we analyze the current situation based on monitoring data on BMI collected in 2011 and 2014, and obtain overall estimates of overweight/obesity and obesity prevalences for the Nordic Region. Data analysis shows that obesity in adults has increased from 2011 to 2014, while no significant changes were found for children. No significant increases were found for mean BMI and overweight/obesity prevalence. Obesity prevention initiatives among the Nordic countries are highly similar although minor differences are present, which is rooted in transnational Nordic cooperation and comparable societal structures.

Healing of damaged metal by a pulsed high-energy electromagnetic field

NASA Astrophysics Data System (ADS)

Kukudzhanov, K. V.; Levitin, A. L.

2018-04-01

The processes of defect (intergranular micro-cracks) transformation are investigated for metal samples in a high-energy short-pulsed electromagnetic field. This investigation is based on a numerical coupled model of the impact of high-energy electromagnetic field on the pre-damaged thermal elastic-plastic material with defects. The model takes into account the melting and evaporation of the metal and the dependence of its physical and mechanical properties on the temperature. The system of equations is solved numerically by finite element method with an adaptive mesh using the arbitrary Euler–Lagrange method. The calculations show that the welding of the crack and the healing of micro-defects under treatment by short pulses of the current takes place. For the macroscopic description of the healing process, the healing and damage parameters of the material are introduced. The healing of micro-cracks improves the material healing parameter and reduces its damage. The micro-crack shapes practically do not affect the time-dependence of the healing and damage under the treatment by the current pulses. These changes are affected only by the value of the initial damage of the material and the initial length of the micro-crack. The time-dependence of the healing and the damage is practically the same for all different shapes of micro-defects, provided that the initial lengths of micro-cracks and the initial damages are the same for these different shapes of defects.

Nanosecond repetitively pulsed discharges in air at atmospheric pressure—the spark regime

NASA Astrophysics Data System (ADS)

Pai, David Z.; Lacoste, Deanna A.; Laux, Christophe O.

2010-12-01

Nanosecond repetitively pulsed (NRP) spark discharges have been studied in atmospheric pressure air preheated to 1000 K. Measurements of spark initiation and stability, plasma dynamics, gas temperature and current-voltage characteristics of the spark regime are presented. Using 10 ns pulses applied repetitively at 30 kHz, we find that 2-400 pulses are required to initiate the spark, depending on the applied voltage. Furthermore, about 30-50 pulses are required for the spark discharge to reach steady state, following initiation. Based on space- and time-resolved optical emission spectroscopy, the spark discharge in steady state is found to ignite homogeneously in the discharge gap, without evidence of an initial streamer. Using measured emission from the N2 (C-B) 0-0 band, it is found that the gas temperature rises by several thousand Kelvin in the span of about 30 ns following the application of the high-voltage pulse. Current-voltage measurements show that up to 20-40 A of conduction current is generated, which corresponds to an electron number density of up to 1015 cm-3 towards the end of the high-voltage pulse. The discharge dynamics, gas temperature and electron number density are consistent with a streamer-less spark that develops homogeneously through avalanche ionization in volume. This occurs because the pre-ionization electron number density of about 1011 cm-3 produced by the high frequency train of pulses is above the critical density for streamer-less discharge development, which is shown to be about 108 cm-3.

Rotational and X-ray luminosity evolution of high-B radio pulsars

NASA Astrophysics Data System (ADS)

Benli, Onur; Ertan, Ünal

2018-05-01

In continuation of our earlier work on the long-term evolution of the so-called high-B radio pulsars (HBRPs) with measured braking indices, we have investigated the long-term evolution of the remaining five HBRPs for which braking indices have not been measured yet. This completes our source-by-source analyses of HBRPs in the fallback disc model that was also applied earlier to anomalous X-ray pulsars (AXPs), soft gamma repeaters (SGRs), and dim isolated neutron stars (XDINs). Our results show that the X-ray luminosities and the rotational properties of these rather different neutron star populations can be acquired by neutron stars with fallback discs as a result of differences in their initial conditions, namely the initial disc mass, initial period and the dipole field strength. For the five HBRPs, unlike for AXPs, SGRs and XDINs, our results do not constrain the dipole field strengths of the sources. We obtain evolutionary paths leading to the properties of HBRPs in the propeller phase with dipole fields sufficiently strong to produce pulsed radio emission.

High quality garbage: A neural network plastic sorter in hardware and software

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

Stanton, S.L.; Alam, M.K.; Hebner, G.A.

1993-09-01

In order to produce pure polymer streams from post-consumer waste plastics, a quick, accurate and relatively inexpensive method of sorting needs to be implemented. This technology has been demonstrated by using near-infrared spectroscopy reflectance data and neural network classification techniques. Backpropagation neural network routines have been developed to run real-time sortings in the lab, using a laboratory-grade spectrometer. In addition, a new reflectance spectrometer has been developed which is fast enough for commercial use. Initial training and test sets taken with the laboratory instrument show that a network is capable of learning 100% when classifying 5 groups of plastic (HDPEmore » and LDPE combined), and up to 100% when classifying 6 groups. Initial data sets from the new instrument have classified plastics into all seven groups with varying degrees of success. One of the initial networks has been implemented in hardware, for high speed computations, and thus rapid classification. Two neural accelerator systems have been evaluated, one based on the Intel 8017ONX chip, and another on the AT&T ANNA chip.« less

Active RNAP pre-initiation sites are highly mutated by cytidine deaminases in yeast, with AID targeting small RNA genes

PubMed Central

Taylor, Benjamin JM; Wu, Yee Ling; Rada, Cristina

2014-01-01

Cytidine deaminases are single stranded DNA mutators diversifying antibodies and restricting viral infection. Improper access to the genome leads to translocations and mutations in B cells and contributes to the mutation landscape in cancer, such as kataegis. It remains unclear how deaminases access double stranded genomes and whether off-target mutations favor certain loci, although transcription and opportunistic access during DNA repair are thought to play a role. In yeast, AID and the catalytic domain of APOBEC3G preferentially mutate transcriptionally active genes within narrow regions, 110 base pairs in width, fixed at RNA polymerase initiation sites. Unlike APOBEC3G, AID shows enhanced mutational preference for small RNA genes (tRNAs, snoRNAs and snRNAs) suggesting a putative role for RNA in its recruitment. We uncover the high affinity of the deaminases for the single stranded DNA exposed by initiating RNA polymerases (a DNA configuration reproduced at stalled polymerases) without a requirement for specific cofactors. DOI: http://dx.doi.org/10.7554/eLife.03553.001 PMID:25237741

Phosphorylation of eIF2α via the general control kinase, GCN2, modulates the ability of renal medullary cells to survive high urea stress

PubMed Central

Cai, Qi

2011-01-01

The phosphorylation of the α-subunit of the eukaryotic translation initiation factor 2 (eIF2α) occurs under many stress conditions in mammalian cells and is mediated by one of four eIF2α kinases: PERK, PKR, GCN2, and HRI. Cells of the renal medulla are regularly exposed to fluctuating concentrations of urea and sodium, the extracellular solutes responsible for the high osmolality in the renal medulla, and thus the kidneys ability to concentrate the urine in times of dehydration. Urea stress is known to initiate molecular responses that diverge from those seen in response to hypertonic stress (NaCl). We show that urea-inducible GCN2 activation initiates the phosphorylation of eIF2α and the downstream increase of activating transcription factor 3 (ATF3). Loss of GCN2 sensitized cells to urea stress, increasing the expression of activated caspase-3 and decreasing cell survival. Loss of GCN2 ablated urea-induced phosphorylation of eIF2α and reduced the expression of ATF3. PMID:21880833

Myeloma Xenograft Destruction by a Nonviral Vector Delivering Oncolytic Infectious Nucleic Acid

PubMed Central

Hadac, Elizabeth M; Kelly, Elizabeth J; Russell, Stephen J

2011-01-01

The feasibility of using a nonviral vector formulation to initiate an oncolytic viral infection has not been previously demonstrated. We therefore sought to determine whether infectious nucleic acid (INA) could be used in place of virus particles to initiate an oncolytic picornavirus infection in vivo. Infectious RNA encoding coxsackievirus A21 (CVA21) was transcribed from plasmid DNA using T7 polymerase. Within 48 hours of injecting this RNA into KAS6/1 myeloma xenografts, high titers of infectious CVA21 virions were detected in the bloodstream. Tumors regressed rapidly thereafter and mice developed signs of myositis. At euthanasia, CVA21 was recovered from regressing tumors and from skeletal muscles. Treatment outcomes were comparable following intratumoral injection of naked RNA or fully infectious CVA21 virus. Dose–response studies showed that an effective oncolytic infection could be established by intratumoral injection of 1 µg of infectious RNA. The oncolytic infection could also be initiated by intravenous injection of infectious RNA. Our study demonstrates that INA is a highly promising alternative drug formulation for oncolytic virotherapy. PMID:21505425

The First New Zealanders: Patterns of Diet and Mobility Revealed through Isotope Analysis

PubMed Central

Kinaston, Rebecca L.; Walter, Richard K.; Jacomb, Chris; Brooks, Emma; Tayles, Nancy; Halcrow, Sian E.; Stirling, Claudine; Reid, Malcolm; Gray, Andrew R.; Spinks, Jean; Shaw, Ben; Fyfe, Roger; Buckley, Hallie R.

2013-01-01

Direct evidence of the environmental impact of human colonization and subsequent human adaptational responses to new environments is extremely rare anywhere in the world. New Zealand was the last Polynesian island group to be settled by humans, who arrived around the end of the 13th century AD. Little is known about the nature of human adaptation and mobility during the initial phase of colonization. We report the results of the isotopic analysis (carbon, nitrogen and strontium) of the oldest prehistoric skeletons discovered in New Zealand to assess diet and migration patterns. The isotope data show that the culturally distinctive burials, Group 1, had similar diets and childhood origins, supporting the assertion that this group was distinct from Group 2/3 and may have been part of the initial colonizing population at the site. The Group 2/3 individuals displayed highly variable diets and likely lived in different regions of the country before their burial at Wairau Bar, supporting the archaeological evidence that people were highly mobile in New Zealand since the initial phase of human settlement. PMID:23691250

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

Martinez, Andre P.; Carrillo, Jan-Michael Y.; Dobrynin, Andrey V.

The molecular weight and polydispersity of the chains in a polymer brush are critical parameters determining the brush properties. However, the characterization of polymer brushes is hindered by the vanishingly small mass of polymer present in brush layers. In this study, in order to obtain sufficient quantities of polymer for analysis, polymer brushes were grown from high surface area fibrous nylon membranes by ATRP. We synthesized the brushes with varying surface initiator densities, polymerization times, and amounts of sacrificial initiator, then cleaved from the substrate, and analyzed by GPC and NMR. Characterization showed that the surface-grown polymer chains were moremore » polydisperse and had lower average molecular weight compared to solution-grown polymers synthesized concurrently. Furthermore, the molecular weight distribution of the polymer brushes was observed to be bimodal, with a low molecular weight population of chains representing a significant mass fraction of the polymer chains at high surface initiator densities. Moreover, the origin of this low MW polymer fraction is proposed to be the termination of growing chains by recombination during the early stages of polymerization, a mechanism confirmed by molecular dynamics simulations of brush polymerization.« less

Edge-oriented dual-dictionary guided enrichment (EDGE) for MRI-CT image reconstruction.

PubMed

Li, Liang; Wang, Bigong; Wang, Ge

2016-01-01

In this paper, we formulate the joint/simultaneous X-ray CT and MRI image reconstruction. In particular, a novel algorithm is proposed for MRI image reconstruction from highly under-sampled MRI data and CT images. It consists of two steps. First, a training dataset is generated from a series of well-registered MRI and CT images on the same patients. Then, an initial MRI image of a patient can be reconstructed via edge-oriented dual-dictionary guided enrichment (EDGE) based on the training dataset and a CT image of the patient. Second, an MRI image is reconstructed using the dictionary learning (DL) algorithm from highly under-sampled k-space data and the initial MRI image. Our algorithm can establish a one-to-one correspondence between the two imaging modalities, and obtain a good initial MRI estimation. Both noise-free and noisy simulation studies were performed to evaluate and validate the proposed algorithm. The results with different under-sampling factors show that the proposed algorithm performed significantly better than those reconstructed using the DL algorithm from MRI data alone.

The epidemiology of physical attack and rape among crack-using women.

PubMed

Falck, R S; Wang, J; Carlson, R G; Siegal, H A

2001-02-01

This prospective study examines the epidemiology of physical attack and rape among a sample of 171 not-in-treatment, crack-cocaine using women. Since initiating crack use, 62% of the women reported suffering a physical attack. The annual rate of victimization by physical attack was 45%. Overall, more than half of the victims sought medical care subsequent to an attack. The prevalence of rape since crack use was initiated was 32%, and the annual rate was 11%. Among those women having been raped since they initiated crack use, 83% reported they were high on crack when the crime occurred as were an estimated 57% of the perpetrators. Logistic regression analyses showed that duration of crack use, arrest for prostitution, and some college education were predictors of having experienced a physical attack. Duration of crack use and a history of prostitution were predictors of suffering a rape. Drug abuse treatment programs must be sensitive to high levels of violence victimization experienced by crack-cocaine using women. Screening women for victimization, and treating the problems that emanate from it, may help make drug abuse treatment more effective.

Early dynamical evolution of young substructured clusters

NASA Astrophysics Data System (ADS)

Dorval, Julien; Boily, Christian

2017-03-01

Stellar clusters form with a high level of substructure, inherited from the molecular cloud and the star formation process. Evidence from observations and simulations also indicate the stars in such young clusters form a subvirial system. The subsequent dynamical evolution can cause important mass loss, ejecting a large part of the birth population in the field. It can also imprint the stellar population and still be inferred from observations of evolved clusters. Nbody simulations allow a better understanding of these early twists and turns, given realistic initial conditions. Nowadays, substructured, clumpy young clusters are usually obtained through pseudo-fractal growth and velocity inheritance. We introduce a new way to create clumpy initial conditions through a ''Hubble expansion'' which naturally produces self consistent clumps, velocity-wise. In depth analysis of the resulting clumps shows consistency with hydrodynamical simulations of young star clusters. We use these initial conditions to investigate the dynamical evolution of young subvirial clusters. We find the collapse to be soft, with hierarchical merging leading to a high level of mass segregation. The subsequent evolution is less pronounced than the equilibrium achieved from a cold collapse formation scenario.

Differences in Neural Correlates of Speech Perception in 3 Month Olds at High and Low Risk for Autism Spectrum Disorder.

PubMed

Edwards, Laura A; Wagner, Jennifer B; Tager-Flusberg, Helen; Nelson, Charles A

2017-10-01

In this study, we investigated neural precursors of language acquisition as potential endophenotypes of autism spectrum disorder (ASD) in 3-month-old infants at high and low familial ASD risk. Infants were imaged using functional near-infrared spectroscopy while they listened to auditory stimuli containing syllable repetitions; their neural responses were analyzed over left and right temporal regions. While female low risk infants showed initial neural activation that decreased over exposure to repetition-based stimuli, potentially indicating a habituation response to repetition in speech, female high risk infants showed no changes in neural activity over exposure. This finding may indicate a potential neural endophenotype of language development or ASD specific to females at risk for the disorder.

Georgia's breastfeeding promotion program for low-income women.

PubMed

Ahluwalia, I B; Tessaro, I; Grummer-Strawn, L M; MacGowan, C; Benton-Davis, S

2000-06-01

Beginning in 1990, Georgia's Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) initiated 5 new strategies to promote breastfeeding among its pregnant and postpartum clients. These strategies were implemented in 1991, each to be provided as an addition to its standard program of counseling on breastfeeding and distributing appropriate literature: 1) enhanced breastfeeding education, 2) breast pump loans, 3) hospital-based programs, 4) peer counseling, and 5) community coalitions. The enhanced breastfeeding education strategy provides access to a hotline as well as periodic training of staff, and the breast pump loan provides free breast pumps to mothers who want to use them. The hospital-based strategy provides bedside support and counseling to women who have just given birth and includes staff training, as well as a hotline number for women to call after they leave the hospital. The peer-counseling strategy focuses on identifying former WIC participants who have successfully breastfed their infants; these women are recruited to provide support and encouragement to current WIC participants. Finally, the community coalitions approach is designed to identify existing community attitudes about breastfeeding, establish plans to address gaps in breastfeeding services, to develop resource guides on breastfeeding for the community, and to advocate at the community level to support breastfeeding women. The objective of our research was to evaluate the impact of breastfeeding promotion strategies on breastfeeding initiation among WIC participants in Georgia. Using data from the Pregnancy Nutrition Surveillance System (PNSS) for 1992-1996, we examined breastfeeding initiation rate during this period and compared rates among 6 different intervention strategies. Also, we used data from the Pregnancy Risk Assessment Monitoring System (PRAMS) to assess breastfeeding initiation and duration among WIC enrollees. We conducted 13 focus groups to understand the experiences of program participants. Ten focus groups were conducted with women who were breastfeeding their infants, 3 each with women from the community coalitions, hospital-based programs, and standard education programs, and 1 with women from the breast pump loan program. Three focus groups were conducted with women who were feeding their infants formula. PNSS data show that breastfeeding initiation increased in the Georgia WIC program from 31.6% in 1992 to 39.5% in 1996. PRAMS data confirmed the increase in breastfeeding initiation from 33.6% (standard error [SE]: 2.2) in 1993 to 42.1% (SE: 2.4) in 1996 among WIC participants. Both datasets (PRAMS and PNSS) showed breastfeeding initiation to be well below the year 2000 goal of 75%. Overall, PRAMS data show a high breastfeeding initiation among non-WIC participants (range: 64.7% [SE: 2.2]) for 1994 to 70.1% (SE: 2.2) in 1996. The percent change between 1993 and 1996 was 8% for non-WIC participants, and it was 25% for the WIC participants among those responding to the PRAMS questionnaire. Data from PRAMS indicated no statistical change in the percentage of WIC enrollees who breastfed their infants for 8 weeks or more; this estimate was 18.3% (95% confidence interval (CI): 14.9-21.8) in 1993 and 19.4% (95% CI: 15.7-23.2) in 1996, well below the Healthy People 2000 objective of 50% at 6 months. According to PNSS data, the largest increases in breastfeeding initiation for 1992 to 1996 were among younger women (

In vivo oxidation in remelted highly cross-linked retrievals.

PubMed

Currier, B H; Van Citters, D W; Currier, J H; Collier, J P

2010-10-20

Elimination of free radicals to prevent oxidation has played a major role in the development and product differentiation of the latest generation of highly cross-linked ultra-high molecular weight polyethylene bearing materials. In the current study, we (1) examined oxidation in a series of retrieved remelted highly cross-linked ultra-high molecular weight polyethylene bearings from a number of device manufacturers and (2) compared the retrieval results with findings for shelf-stored control specimens. The hypothesis was that radiation-cross-linked remelted ultra-high molecular weight polyethylene would maintain oxidative stability in vivo comparable with the stability during shelf storage and in published laboratory aging tests. Fifty remelted highly cross-linked ultra-high molecular weight polyethylene acetabular liners and nineteen remelted highly cross-linked ultra-high molecular weight polyethylene tibial inserts were received after retrieval from twenty-one surgeons from across the U.S. Thirty-two of the retrievals had been in vivo for two years or more. Each was measured for oxidation with use of Fourier transform infrared spectroscopy. A control series of remelted highly cross-linked ultra-high molecular weight polyethylene acetabular liners from three manufacturers was analyzed with electron paramagnetic resonance spectroscopy to measure free radical content and with Fourier transform infrared spectroscopy to measure oxidation initially and after eight to nine years of shelf storage in air. The never-implanted, shelf-aged controls had no measurable free-radical content initially or after eight to nine years of shelf storage. The never-implanted controls showed no increase in oxidation during shelf storage. Oxidation measurements showed measurable oxidation in 22% of the retrieved remelted highly cross-linked liners and inserts after an average of two years in vivo. Because never-implanted remelted highly cross-linked ultra-high molecular weight polyethylene materials had no measurable free-radical concentration and no increase in oxidation during shelf storage, these materials were expected to be oxidation-resistant in vivo. However, some remelted highly cross-linked ultra-high molecular weight polyethylene retrievals showed measurable oxidation after an average of more than two years in vivo. This apparent departure from widely expected behavior requires continued study of the process of in vivo oxidation of ultra-high molecular weight polyethylene materials.

Validating continuous digital light processing (cDLP) additive manufacturing accuracy and tissue engineering utility of a dye-initiator package.

PubMed

Wallace, Jonathan; Wang, Martha O; Thompson, Paul; Busso, Mallory; Belle, Vaijayantee; Mammoser, Nicole; Kim, Kyobum; Fisher, John P; Siblani, Ali; Xu, Yueshuo; Welter, Jean F; Lennon, Donald P; Sun, Jiayang; Caplan, Arnold I; Dean, David

2014-03-01

This study tested the accuracy of tissue engineering scaffold rendering via the continuous digital light processing (cDLP) light-based additive manufacturing technology. High accuracy (i.e., <50 µm) allows the designed performance of features relevant to three scale spaces: cell-scaffold, scaffold-tissue, and tissue-organ interactions. The biodegradable polymer poly (propylene fumarate) was used to render highly accurate scaffolds through the use of a dye-initiator package, TiO2 and bis (2,4,6-trimethylbenzoyl)phenylphosphine oxide. This dye-initiator package facilitates high accuracy in the Z dimension. Linear, round, and right-angle features were measured to gauge accuracy. Most features showed accuracies between 5.4-15% of the design. However, one feature, an 800 µm diameter circular pore, exhibited a 35.7% average reduction of patency. Light scattered in the x, y directions by the dye may have reduced this feature's accuracy. Our new fine-grained understanding of accuracy could be used to make further improvements by including corrections in the scaffold design software. Successful cell attachment occurred with both canine and human mesenchymal stem cells (MSCs). Highly accurate cDLP scaffold rendering is critical to the design of scaffolds that both guide bone regeneration and that fully resorb. Scaffold resorption must occur for regenerated bone to be remodeled and, thereby, achieve optimal strength.

In-situ synthesis of monodisperse micro-nanospherical LiFePO4/carbon cathode composites for lithium-ion batteries

NASA Astrophysics Data System (ADS)

Gong, Hao; Xue, Hairong; Wang, Tao; He, Jianping

2016-06-01

The LiFePO4 is recognized as the promising cathode material, due to its high specific capacity, excellent, structural stability and environmental benignity. However, it is blamed for the low tap density and poor rate performance when served as the cathode materials for a long time. Here, the microspheric LiFePO4/C composites are successfully synthesized through a one-step in-situ solvothermal method combined with carbothermic reduction. These LiFePO4/C microspheres are assembled by LiFePO4 nanoparticles (∼100 nm) and uniformly coated by the carbon, which show a narrow diameter distribution of 4 μm. As a cathode material for lithium ion batteries, the LiFePO4/C composites can deliver an initiate charge capacity of 155 mAh g-1 and retain 90% of initial capacity after 200 cycles at 0.1 C. When cycled at high current densities up to 20 C, it shows a discharge capacity of ∼60 mAh g-1, exhibiting superior rate performance. The significantly improved electrochemical performance of LiFePO4/C composites material can be attributed to its special micro-nano hierarchical structure. Microspheric LiFePO4/C composites exhibit a high tap density about 1.3 g cm-3. What's more, the well-coated carbon insures the high electrical conductivity and the nano-sized LiFePO4/C particles shorten lithium ion transport, thus exhibiting the high specific capacity, high cycling stability and good rate performance.

Too little, too late or too much, too early? Differential hemodynamics of response inhibition in high and low sensation seekers

PubMed Central

Collins, Heather R.; Corbly, Christine R.; Liu, Xun; Kelly, Thomas H.; Lynam, Donald; Joseph, Jane E.

2012-01-01

High sensation seeking is associated with strong approach behaviors and weak avoidance responses. The present study used functional magnetic resonance imaging (fMRI) to further characterize the neurobiological underpinnings of this behavioral profile using a Go/No-go task. Analysis of brain activation associated with response inhibition (No-go) versus response initiation and execution (Go) revealed the commonly reported right lateral prefrontal, insula, cingulate, and supplementary motor area network. However, right lateral activation was associated with greater No-go than Go responses only in low sensation seekers. High sensation seekers showed no differential activation in these regions but a more pronounced Go compared to No-go response in several other regions that are involved in salience detection (insula), motor initiation (anterior cingulate) and attention (inferior parietal cortex). Temporal analysis of the hemodynamic response for Go and No-go conditions revealed that the stronger response to Go than No-go trials in high sensation seekers occurred in in the earliest time window in the right middle frontal gyrus, right mid-cingulate and right precuneus. In contrast, the greater No-go than Go response in low sensation seekers occurred in the later time window in these same regions. These findings indicate that high sensation seekers more strongly attend to or process Go trials and show delayed or minimal inhibitory responses on No-go trials in regions that low sensation seekers use for response inhibition. Failure to engage such regions for response inhibition may underlie some of the risky and impulsive behaviors observed in high sensation seekers. PMID:22902769

High-Temperature Electrochemical Performance of FeF3/C Nanocomposite as a Cathode Material for Lithium-Ion Batteries

NASA Astrophysics Data System (ADS)

Tang, Mengyun; Zhang, Zhengfu; Wang, Zi; Liu, Jingfeng; Yan, Hongge; Peng, Jinhui

2018-02-01

Iron trifluoride has been studied as a cathode material due to its cost-effectiveness, low toxicity, and high theoretical capacities of 712 mA h g-1. However, FeF3 has serious shortcomings of poor electronic conductivity and a slow diffusion rate of lithium ions, leading to a lower reversible specific capacity. In this work, FeF3/C nanocomposite has been synthesized successfully via a high-energy ball-milling method, and acetylene black is used as the conductive agent to improve the conductivity of FeF3. The FeF3/C nanocomposite shows a high initial discharge capacity of 346.25 and 161.58 mA h g-1 after 40th cycle at 50 mA g-1. It exhibits good cycle performance and rate performance. The high-temperature discharge capacities decreased with increase in the temperature. The initial high-temperature discharge capacities are found to be 254.17, 300.01, 281.25 and 125.16, and 216.875, 156, 141.67, 150, and 64.98 mA h g-1 at 20th cycles at the 40, 50, 60, and 70 °C, respectively.

Reminova and EAER: Keeping Enamel Whole through Caries Remineralization.

PubMed

Pitts, N B; Wright, J P

2018-02-01

This article aims to outline the early development of a King's College London dental spinout company, Reminova, formed to commercialize a novel clinical method of caries remineralization: electrically accelerated and enhanced remineralization (EAER). This method is being developed to address the unmet clinical need identified by modern caries management strategies to keep enamel "whole" through remineralization of clinical caries as a form of nonoperative caries treatment for initial-stage and moderate lesions. A progressive movement within dentistry is shifting away from the restorative-only model, which, it is suggested, has failed. The high prevalence of initial-stage caries across populations provides a significant opportunity to prevent restorations and reduce repeat restorations over a patient's lifetime. Reminova has set out to provide a method to repair lesions without drilling, filling, pain, or injections. The article outlines the rationale for and the chronological stages of the technology and company development. It then outlines corroborative evidence to show that EAER treatment can, in this preliminary in vitro investigation, remineralize clinically significant caries throughout the depth of the lesion as measured by Knoop microhardness and corroborated by scanning electron microscopy. Furthermore, the presented data show that EAER-treated enamel is harder than the healthy enamel measured nearby in each sample and is very similar in appearance to healthy enamel from the subjective interpretation made possible by scanning electron microscopy imagery. The data presented also show that this more "complete" remineralization to a high hardness level has been achieved with 2 remineralizing agents via in vitro human tooth samples. The broad clinical potential of this new treatment methodology seems to be very encouraging from these results. Reminova will strive to continue its mission, to ensure that, in the future, dental teams will not need to drill holes for the treatment of initial-stage and moderate caries lesions.

Left ventricular volume estimation in cardiac three-dimensional ultrasound: a semiautomatic border detection approach.

PubMed

van Stralen, Marijn; Bosch, Johan G; Voormolen, Marco M; van Burken, Gerard; Krenning, Boudewijn J; van Geuns, Robert-Jan M; Lancée, Charles T; de Jong, Nico; Reiber, Johan H C

2005-10-01

We propose a semiautomatic endocardial border detection method for three-dimensional (3D) time series of cardiac ultrasound (US) data based on pattern matching and dynamic programming, operating on two-dimensional (2D) slices of the 3D plus time data, for the estimation of full cycle left ventricular volume, with minimal user interaction. The presented method is generally applicable to 3D US data and evaluated on data acquired with the Fast Rotating Ultrasound (FRU-) Transducer, developed by Erasmus Medical Center (Rotterdam, the Netherlands), a conventional phased-array transducer, rotating at very high speed around its image axis. The detection is based on endocardial edge pattern matching using dynamic programming, which is constrained by a 3D plus time shape model. It is applied to an automatically selected subset of 2D images of the original data set, for typically 10 equidistant rotation angles and 16 cardiac phases (160 images). Initialization requires the drawing of four contours per patient manually. We evaluated this method on 14 patients against MRI end-diastole and end-systole volumes. Initialization requires the drawing of four contours per patient manually. We evaluated this method on 14 patients against MRI end-diastolic (ED) and end-systolic (ES) volumes. The semiautomatic border detection approach shows good correlations with MRI ED/ES volumes (r = 0.938) and low interobserver variability (y = 1.005x - 16.7, r = 0.943) over full-cycle volume estimations. It shows a high consistency in tracking the user-defined initial borders over space and time. We show that the ease of the acquisition using the FRU-transducer and the semiautomatic endocardial border detection method together can provide a way to quickly estimate the left ventricular volume over the full cardiac cycle using little user interaction.

The Omega-3 Fatty Acid Eicosapentaenoic Acid Accelerates Disease Progression in a Model of Amyotrophic Lateral Sclerosis

PubMed Central

Gladman, Stacy; Biggio, Maria Luigia; Marino, Marianna; Jayasinghe, Maduka; Ullah, Farhan; Dyall, Simon C.; Malaspina, Andrea; Bendotti, Caterina; Michael-Titus, Adina

2013-01-01

Amyotrophic lateral sclerosis (ALS) is a progressive fatal neurodegenerative disease characterised by loss of motor neurons that currently has no cure. Omega-3 polyunsaturated fatty acids, such as eicosapentaenoic acid (EPA), have many health benefits including neuroprotective and myoprotective potential. We tested the hypothesis that a high level of dietary EPA could exert beneficial effects in ALS. The dietary exposure to EPA (300 mg/kg/day) in a well-established mouse model of ALS expressing the G93A superoxide dismutase 1 (SOD1) mutation was initiated at a pre-symptomatic or symptomatic stage, and the disease progression was monitored until the end stage. Daily dietary EPA exposure initiated at the disease onset did not significantly alter disease presentation and progression. In contrast, EPA treatment initiated at the pre-symptomatic stage induced a significantly shorter lifespan. In a separate group of animals sacrificed before the end stage, the tissue analysis showed that the vacuolisation detected in G93A-SOD1 mice was significantly increased by exposure to EPA. Although EPA did not alter motor neurone loss, EPA reversed the significant increase in activated microglia and the astrocytic activation seen in G93A-SOD1 mice. The microglia in the spinal cord of G93A-SOD1 mice treated with EPA showed a significant increase in 4-hydroxy-2-hexenal, a highly toxic aldehydic oxidation product of omega-3 fatty acids. These data show that dietary EPA supplementation in ALS has the potential to worsen the condition and accelerate the disease progression. This suggests that great caution should be exerted when considering dietary omega-3 fatty acid supplements in ALS patients. PMID:23620776

Effects of feeding a diet containing Gymnema sylvestre extract: Attenuating progression of obesity in C57BL/6J mice.

PubMed

Kim, Hyeon-Jeong; Hong, Seong-Ho; Chang, Seung-Hee; Kim, Sanghwa; Lee, Ah Young; Jang, Yoonjeong; Davaadamdin, Orkhonselenge; Yu, Kyeong-Nam; Kim, Ji-Eun; Cho, Myung-Haing

2016-05-01

To investigate the effect of Gymnema sylvestre extract (GS) on initial anti-obesity, liver injury, and glucose homeostasis induced by a high-fat diet (HFD). The dry powder of GS was extracted with methanol, and gymnemic acid was identified by high performance liquid chromatography as deacyl gymnemic acid. Male C57BL/6J mice that fed on either a normal diet, normal diet containing 1 g/kg GS (CON+GS), HFD, or HFD containing 1.0 g/kg GS (HFD + GS) for 4 weeks were used to test the initial anti-obesity effect of GS. Body weight gain and food intake, and serum levels about lipid and liver injury markers were measured. Histopathology of adipose tissue and liver stained with hematoxylin and eosin (H&E) and oil-red O were analyzed. After 4 weeks of GS extract feeding, intraperitoneal glucose tolerance test (IPGTT) was performed. The methanol extracts of GS exerted significant anti-obesity effects in HFD + GS group. They decreased body weight gain, a lower food and energy efficiency ratio, and showed lower serum levels of total cholesterol (TC), triglyceride (TG), low-density lipoprotein (LDL)-cholesterol, very-low density lipoprotein (VLDL)-cholesterol and leptin compared with the HFD group. The decreases of abdominal as well as epididymal fat weight and adipocyte hypertrophy, lipid droplets in liver, and serum levels of aspartate aminotransferase (AST) and alanine transaminase (ALT) were also observed. The CON + GS group showed an effect of glucose homeostasis compared to the CON group. This study shows that GS provide the possibility as a key role in an initial anti-obesity effects feeding with a HFD. Copyright © 2016 Hainan Medical College. Production and hosting by Elsevier B.V. All rights reserved.

The Neutrality Act of 1935: An Inquiry into the Uses of History. Teacher and Student Manuals.

ERIC Educational Resources Information Center

Scudder, Edson F.

This unit, geared initially for college-preparatory students at the high school level, asks the student to consider ways in which the past, however incompletely or inaccurately perceived, shapes our views of the present. Evidence is presented to show how both the isolationists and internationalists justified their actions by their interpretations…

EVALUATION OF FGD DRY INJECTION SORBENTS AND ADDITIVES - VOLUME 2 - PILOT PLANT EVALUATION OF HIGH REACTIVITY SORBENTS

EPA Science Inventory

The report describes a mini-pilot test program to investigate potential new sorbents and processes for dry SO2 removal. Initial tests showed that the 85 cu m/h pilot plant could be used successfully to evaluate both spray dryer and dry injection processes using traditional calciu...

The Scholarship of Teaching and Learning: Challenges for Malaysian Academics

ERIC Educational Resources Information Center

Harland, Tony; Raja Hussain, Raja Maznah; Bakar, Aishah Abu

2014-01-01

This paper explores the adoption of the scholarship of teaching and learning (SoTL) by 10 Malaysian university academics. SoTL was part of a pioneering sector-wide initiative for improving teaching and learning. The qualitative study showed that there had been no true learning phase for SoTL because academics had high expectations of rapid success…

Very High Cycle Fatigue Failure Analysis and Life Prediction of Cr-Ni-W Gear Steel Based on Crack Initiation and Growth Behaviors.

PubMed

Deng, Hailong; Li, Wei; Sakai, Tatsuo; Sun, Zhenduo

2015-12-02

The unexpected failures of structural materials in very high cycle fatigue (VHCF) regime have been a critical issue in modern engineering design. In this study, the VHCF property of a Cr-Ni-W gear steel was experimentally investigated under axial loading with the stress ratio of R = -1, and a life prediction model associated with crack initiation and growth behaviors was proposed. Results show that the Cr-Ni-W gear steel exhibits the constantly decreasing S-N property without traditional fatigue limit, and the fatigue strength corresponding to 10⁸ cycles is around 485 MPa. The inclusion-fine granular area (FGA)-fisheye induced failure becomes the main failure mechanism in the VHCF regime, and the local stress around the inclusion play a key role. By using the finite element analysis of representative volume element, the local stress tends to increase with the increase of elastic modulus difference between inclusion and matrix. The predicted crack initiation life occupies the majority of total fatigue life, while the predicted crack growth life is only accounts for a tiny fraction. In view of the good agreement between the predicted and experimental results, the proposed VHCF life prediction model involving crack initiation and growth can be acceptable for inclusion-FGA-fisheye induced failure.

Improved prediction of severe thunderstorms over the Indian Monsoon region using high-resolution soil moisture and temperature initialization

PubMed Central

Osuri, K. K.; Nadimpalli, R.; Mohanty, U. C.; Chen, F.; Rajeevan, M.; Niyogi, D.

2017-01-01

The hypothesis that realistic land conditions such as soil moisture/soil temperature (SM/ST) can significantly improve the modeling of mesoscale deep convection is tested over the Indian monsoon region (IMR). A high resolution (3 km foot print) SM/ST dataset prepared from a land data assimilation system, as part of a national monsoon mission project, showed close agreement with observations. Experiments are conducted with (LDAS) and without (CNTL) initialization of SM/ST dataset. Results highlight the significance of realistic land surface conditions on numerical prediction of initiation, movement and timing of severe thunderstorms as compared to that currently being initialized by climatological fields in CNTL run. Realistic land conditions improved mass flux, convective updrafts and diabatic heating in the boundary layer that contributed to low level positive potential vorticity. The LDAS run reproduced reflectivity echoes and associated rainfall bands more efficiently. Improper representation of surface conditions in CNTL run limit the evolution boundary layer processes and thereby failed to simulate convection at right time and place. These findings thus provide strong support to the role land conditions play in impacting the deep convection over the IMR. These findings also have direct implications for improving heavy rain forecasting over the IMR, by developing realistic land conditions. PMID:28128293

High-mobility group 1/2 proteins are essential for initiating rolling-circle-type DNA replication at a parvovirus hairpin origin.

PubMed

Cotmore, S F; Tattersall, P

1998-11-01

Rolling-circle replication is initiated by a replicon-encoded endonuclease which introduces a single-strand nick into specific origin sequences, becoming covalently attached to the 5' end of the DNA at the nick and providing a 3' hydroxyl to prime unidirectional, leading-strand synthesis. Parvoviruses, such as minute virus of mice (MVM), have adapted this mechanism to amplify their linear single-stranded genomes by using hairpin telomeres which sequentially unfold and refold to shuttle the replication fork back and forth along the genome, creating a continuous, multimeric DNA strand. The viral initiator protein, NS1, then excises individual genomes from this continuum by nicking and reinitiating synthesis at specific origins present within the hairpin sequences. Using in vitro assays to study ATP-dependent initiation within the right-hand (5') MVM hairpin, we have characterized a HeLa cell factor which is absolutely required to allow NS1 to nick this origin. Unlike parvovirus initiation factor (PIF), the cellular complex which activates NS1 endonuclease activity at the left-hand (3') viral origin, the host factor which activates the right-hand hairpin elutes from phosphocellulose in high salt, has a molecular mass of around 25 kDa, and appears to bind preferentially to structured DNA, suggesting that it might be a member of the high-mobility group 1/2 (HMG1/2) protein family. This prediction was confirmed by showing that purified calf thymus HMG1 and recombinant human HMG1 or murine HMG2 could each substitute for the HeLa factor, activating the NS1 endonuclease in an origin-specific nicking reaction.

Unraveling the proteomic profile of mice testis during the initiation of meiosis.

PubMed

Shao, Binbin; Guo, Yueshuai; Wang, Lei; Zhou, Quan; Gao, Tingting; Zheng, Bo; Zheng, Haoyu; Zhou, Tao; Zhou, Zuomin; Guo, Xuejiang; Huang, Xiaoyan; Sha, Jiahao

2015-04-29

In mice, once primordial germ cells (PGCs) are generated, they continue to proliferate and migrate to eventually reach the future gonads. They initiate sexual differentiation after their colonization of the gonads. During this process, retinoic acid (RA) induces meiosis in the female germ cells, which proceeds to the diplotene stage of meiotic prophase I, whereas the male germ cells initiate growth arrest. After birth, meiosis is initiated in mice spermatogonia by their conversion to preleptotene spermatocytes. There are evidences showing the roles of RA in the regulation of spermatogonial differentiation and meiosis initiation. However, it is still not well known on what responds to RA and how RA signaling engages meiosis. Thus, we constructed a proteomic profile of proteins associated with meiosis onset during testis development in mouse and identified 104 differentially expressed proteins (≥1.5 folds). Bioinformatic analysis showed proteins functioning in specific cell processes. The expression patterns of five selected proteins were verified via Western blot, of which we found that Tfrc gene was RA responsive, with a RA responsive element, and could be up regulated by RA in spermatogonial stem cell (SSC) line. Taken together, the results provide an important reference profile for further functional study of meiosis initiation. Spermatogenesis involves mitosis of spermatogonia, meiosis of spermatocytes and spermiogenesis, in which meiosis is a unique event to germ cells, and not in the somatic cells. Till now, the detailed molecular mechanisms of the transition from mitosis to meiosis are still not elucidated. With high-throughput proteomic technology, it is now possible to systemically identify proteins possibly involved. With TMT-6plex based quantification, we identified 104 proteins differentially between testes without meiosis (day 8.5) and those that were meiosis initiated (day 10.5). And a well-known protein essential for meiosis initiation, stra8, was identified to be differentially expressed in the study. And bioinformatic analysis and functional studies revealed several proteins regulated by retinoic acid, a chemical known to regulate the meiosis initiation. Thus, this quantitative proteomic approach can identify meiosis initiation regulating proteins, and further functional studies of these proteins will help elucidate the mechanisms of meiosis initiation. Copyright © 2015. Published by Elsevier B.V.

Subharmonic and fundamental high amplitude excitation of an axisymmetric jet

NASA Technical Reports Server (NTRS)

Raman, Ganesh; Rice, Edward J.

1989-01-01

A circular jet was excited simultaneously by two different harmonically related tones. Data for three pairs of Strouhal numbers (St(D) = f*D/U (sub j) = 0.2 and 0.4, 0.3 and 0.6, 0.4 and 0.8). For each case the initial phase difference between the two waves was varied in steps of 45 deg, for one full cycle and the level of the fundamental and subharmonic forcing were varied independently over the range of 0.1 to 7 percent of the jet exit velocity. Our initial findings concurred with published findings, such as a critical level of the fundamental is required for subharmonic augmentation, the initial phase difference is critical in determining whether the subharmonic is augmented or suppressed. The detailed documentation of several aspects of this phenomenon all measured in one and the same experimental facility in a controlled manner, bring out several important points that eluded previous researchers: (1) At high amplitudes of the fundamental and subharmonic forcing levels the subharmonic augmentation is independent of the initial phase difference. (2) Contrary to the earlier belief that stable pairing could be produced only with an initial laminar boundary layer, the present work shows that by the two-frequency excitation method this phenomenon can be induced over a range of conditions for a jet with an initially turbulent boundary layer. (3) It is seen that two-frequency excitation is indeed more effective than single frequency excitation in jet mixing enhancement. Higher spreading rates seem to go along with higher subharmonic levels.

Bioleaching of arsenic from highly contaminated mine tailings using Acidithiobacillus thiooxidans.

PubMed

Lee, Eunseong; Han, Yosep; Park, Jeonghyun; Hong, Jeongsik; Silva, Rene A; Kim, Seungkon; Kim, Hyunjung

2015-01-01

The behavior of arsenic (As) bioleaching from mine tailings containing high amount of As (ca. 34,000 mg/kg) was investigated using Acidithiobacillus thiooxidans to get an insight on the optimal conditions that would be applied to practical heap and/or tank bioleaching tests. Initial pH (1.8-2.2), temperature (25-40 °C), and solid concentration (0.5-4.0%) were employed as experimental parameters. Complementary characterization experiments (e.g., XRD, SEM-EDS, electrophoretic mobility, cell density, and sulfate production) were also carried out to better understand the mechanism of As bioleaching. The results showed that final As leaching efficiency was similar regardless of initial pH. However, greater initial As leaching rate was observed at initial pH 1.8 than other conditions, which could be attributed to greater initial cell attachment to mine tailings. Unlike the trend observed when varying the initial pH, the final As leaching efficiency varied with the changes in temperature and solid concentration. Specifically, As leaching efficiency tended to decrease with increasing temperature due to the decrease in the bacterial growth rate at higher temperature. Meanwhile, As leaching efficiency tended to increase with decreasing solid concentration. The results for jarosite contents in mine tailings residue after bioleaching revealed that much greater amount of the jarosite was formed during the bioleaching reaction at higher solid concentration, suggesting that the coverage of the surface of the mine tailings by jarosite and/or the co-precipitation of the leached As with jarosite could be a dominant factor reducing As leaching efficiency. Copyright © 2014 Elsevier Ltd. All rights reserved.

Investigation of the Low Velocity Zone Beneath the Southern Basin and Range

NASA Astrophysics Data System (ADS)

Savage, B.; Helmberger, D. V.

2003-12-01

Following the work by Helmberger (1973), we use waveform recordings of P arrivals at distances from 6o to 20o to investigate the structure of the low velocity zone (LVZ) or asthenosphere. In contrast to the previous study, broadband data (TriNet and BDSN) is used at a much smaller station spacing providing higher along path and depth resolution. For this study, a well recorded earthquake in the central Gulf of California (Mw 6.3) produces transitions from PnL to P410 across all of California and western Nevada. The nature of these transitions indicates the thickness and gradients of the LVZ and the lithosphere. Initial findings show large variations of lithosphere and LVZ structure from east to west below California. By varying the lithosphere compressional velocity and depth of the LVZ in 1-D models, a database of synthetics waveforms is created to guide the development of realistic 2-D (along path) and 3-D (against azimuth) description of the lithosphere and asthenosphere. The character of the P arrivals changes dramatically near 9-11o with the emergence of a higher frequencies over-printing the longer-period PnL arrivals. Coastal California stations show these arrivals at the shortest distances, 9o indicating the lithosphere velocity and gradient below the LVZ are high. This is in opposition to those arrivals on the east which do not record the high frequency arrivals until 11o. As the distances reach 13o, a large amplitude, high frequency phase is present 10-15 seconds behind the initial P arrival. The emergence of the large secondary phase occurs at different distances across California with a pattern similar to before. At this distance, a change in the apparent velocity of the first arrival also occurs. Further in distance, the width of the initial P arrival and the energy following, or lack thereof, points to the shape of the underlying LVZ. Coastal stations and those in the central portion of California show larger amplitude arrivals following the initial P arrival than do those to the east. These large secondary arrivals may be due to larger than expected velocity jumps at the bottom of or just below the LVZ. Mapping the transition from the lithosphere to the asthenosphere, fine structure and lateral variation, should prove invaluable for tectonic reconstruction efforts, now in progress.

Initial decomposition of the condensed-phase β-HMX under shock waves: molecular dynamics simulations.

PubMed

Ge, Ni-Na; Wei, Yong-Kai; Ji, Guang-Fu; Chen, Xiang-Rong; Zhao, Feng; Wei, Dong-Qing

2012-11-26

We have performed quantum-based multiscale simulations to study the initial chemical processes of condensed-phase octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) under shock wave loading. A self-consistent charge density-functional tight-binding (SCC-DFTB) method was employed. The results show that the initial decomposition of shocked HMX is triggered by the N-NO(2) bond breaking under the low velocity impact (8 km/s). As the shock velocity increases (11 km/s), the homolytic cleavage of the N-NO(2) bond is suppressed under high pressure, the C-H bond dissociation becomes the primary pathway for HMX decomposition in its early stages. It is accompanied by a five-membered ring formation and hydrogen transfer from the CH(2) group to the -NO(2) group. Our simulations suggest that the initial chemical processes of shocked HMX are dependent on the impact velocity, which gain new insights into the initial decomposition mechanism of HMX upon shock loading at the atomistic level, and have important implications for understanding and development of energetic materials.

Protein Phosphatase 4 Promotes Chromosome Pairing and Synapsis, and Contributes to Maintaining Crossover Competence with Increasing Age

PubMed Central

Sato-Carlton, Aya; Li, Xuan; Crawley, Oliver; Testori, Sarah; Martinez-Perez, Enrique; Sugimoto, Asako; Carlton, Peter M.

2014-01-01

Prior to the meiotic divisions, dynamic chromosome reorganizations including pairing, synapsis, and recombination of maternal and paternal chromosome pairs must occur in a highly regulated fashion during meiotic prophase. How chromosomes identify each other's homology and exclusively pair and synapse with their homologous partners, while rejecting illegitimate synapsis with non-homologous chromosomes, remains obscure. In addition, how the levels of recombination initiation and crossover formation are regulated so that sufficient, but not deleterious, levels of DNA breaks are made and processed into crossovers is not understood well. We show that in Caenorhabditis elegans, the highly conserved Serine/Threonine protein phosphatase PP4 homolog, PPH-4.1, is required independently to carry out four separate functions involving meiotic chromosome dynamics: (1) synapsis-independent chromosome pairing, (2) restriction of synapsis to homologous chromosomes, (3) programmed DNA double-strand break initiation, and (4) crossover formation. Using quantitative imaging of mutant strains, including super-resolution (3D-SIM) microscopy of chromosomes and the synaptonemal complex, we show that independently-arising defects in each of these processes in the absence of PPH-4.1 activity ultimately lead to meiotic nondisjunction and embryonic lethality. Interestingly, we find that defects in double-strand break initiation and crossover formation, but not pairing or synapsis, become even more severe in the germlines of older mutant animals, indicating an increased dependence on PPH-4.1 with increasing maternal age. Our results demonstrate that PPH-4.1 plays multiple, independent roles in meiotic prophase chromosome dynamics and maintaining meiotic competence in aging germlines. PP4's high degree of conservation suggests it may be a universal regulator of meiotic prophase chromosome dynamics. PMID:25340746

Aerodynamics and flow features of a damselfly in takeoff flight.

PubMed

Bode-Oke, Ayodeji T; Zeyghami, Samane; Dong, Haibo

2017-09-26

Flight initiation is fundamental for survival, escape from predators and lifting payload from one place to another in biological fliers and can be broadly classified into jumping and non-jumping takeoffs. During jumping takeoffs, the legs generate most of the initial impulse. Whereas the wings generate most of the forces in non-jumping takeoffs, which are usually voluntary, slow, and stable. It is of great interest to understand how these non-jumping takeoffs occur and what strategies insects use to generate large amount of forces required for this highly demanding flight initiation mode. Here, for the first time, we report accurate wing and body kinematics measurements of a damselfly during a non-jumping takeoff. Furthermore, using a high fidelity computational fluid dynamics simulation, we identify the 3D flow features and compute the wing aerodynamics forces to unravel the key mechanisms responsible for generating large flight forces. Our numerical results show that a damselfly generates about three times its body weight during the first half-stroke for liftoff. In generating these forces, the wings flap through a steeply inclined stroke plane with respect to the horizon, slicing through the air at high angles of attack (45°-50°). Consequently, a leading edge vortex (LEV) is formed during both the downstroke and upstroke on all the four wings. The formation of the LEV, however, is inhibited in the subsequent upstrokes following takeoff. Accordingly, we observe a drastic reduction in the magnitude of the aerodynamic force, signifying the importance of LEV in augmenting force production. Our analysis also shows that forewing-hindwing interaction plays a favorable role in enhancing both lift and thrust production during takeoff.

Formation of Manganese Oxide Coatings onto Sand for Adsorption of Trace Metals from Groundwater.

PubMed

Tilak, A S; Ojewole, S; Williford, C W; Fox, G A; Sobecki, T M; Larson, S L

2013-11-01

Manganese oxide (MnO) occurs naturally in soil and has a high affinity for trace metals adsorption. In this work, we quantified the factors (pH; flow rate; use of oxidants such as bleach, HO, and O; initial Mn(II) concentrations; and two types of geologic media) affecting MnO coatings onto Ottawa and aquifer sand using batch and column experiments. The batch experiments consisted of manual and automated titration, and the column experiments mimicked natural MnO adsorption and oxidation cycles as a strategy for in situ adsorption. A Pb solution of 50 mg L was passed through MnO-coated sand at a flow rate of 4 mL min to determine its adsorption capacity. Batch experimental results showed that MnO coatings increased from pH 6 to 8, with maximum MnO coating occurring at pH 8. Regarding MnO coatings, bleach and O were highly effective compared with HO. The Ottawa sand had approximately twice the MnO coating of aquifer sand. The sequential increase in initial Mn(II) concentrations on both sands resulted in incremental buildup of MnO. The automated procedure enhanced MnO coatings by 3.5 times compared with manual batch experiments. Column results showed that MnO coatings were highly dependent on initial Mn(II) and oxidant concentrations, pH, flow rate, number of cycles (h), and the type of geologic media used. Manganese oxide coating exceeded 1700 mg kg for Ottawa sand and 130 mg kg for aquifer sand. The Pb adsorption exceeded 2200 mg kg for the Ottawa sand and 300 mg kg for the aquifer sand. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

A Magnetohydrodynamic Simulation of Magnetic Null-point Reconnections in NOAA AR 12192, Initiated with an Extrapolated Non-force-free Field

NASA Astrophysics Data System (ADS)

Prasad, A.; Bhattacharyya, R.; Hu, Qiang; Kumar, Sanjay; Nayak, Sushree S.

2018-06-01

The magnetohydrodynamics of the solar corona is simulated numerically. The simulation is initialized with an extrapolated non-force-free magnetic field using the vector magnetogram of the active region NOAA 12192, which was obtained from the solar photosphere. Particularly, we focus on the magnetic reconnections (MRs) occurring close to a magnetic null point that resulted in the appearance of circular chromospheric flare ribbons on 2014 October 24 around 21:21 UT, after the peak of an X3.1 flare. The extrapolated field lines show the presence of the three-dimensional (3D) null near one of the polarity-inversion lines—where the flare was observed. In the subsequent numerical simulation, we find MRs occurring near the null point, where the magnetic field lines from the fan plane of the 3D null form a X-type configuration with underlying arcade field lines. The footpoints of the dome-shaped field lines, inherent to the 3D null, show high gradients of the squashing factor. We find slipping reconnections at these quasi-separatrix layers, which are co-located with the post-flare circular brightening observed at chromospheric heights. This demonstrates the viability of the initial non-force-free field, along with the dynamics it initiates. Moreover, the initial field and its simulated evolution are found to be devoid of any flux rope, which is congruent with the confined nature of the flare.

Amorphization and nanocrystallization of silcon under shock compression

DOE PAGES

Remington, B. A.; Wehrenberg, C. E.; Zhao, S.; ...

2015-11-06

High-power, short-duration, laser-driven, shock compression and recovery experiments on [001] silicon unveiled remarkable structural changes above a pressure threshold. Two distinct amorphous regions were identified: (a) a bulk amorphous layer close to the surface and (b) amorphous bands initially aligned with {111} slip planes. Further increase of the laser energy leads to the re-crystallization of amorphous silicon into nanocrystals with high concentration of nano-twins. This amorphization is produced by the combined effect of high magnitude hydrostatic and shear stresses under dynamic shock compression. Shock-induced defects play a very important role in the onset of amorphization. Calculations of the free energymore » changes with pressure and shear, using the Patel-Cohen methodology, are in agreement with the experimental results. Molecular dynamics simulation corroborates the amorphization, showing that it is initiated by the nucleation and propagation of partial dislocations. As a result, the nucleation of amorphization is analyzed qualitatively by classical nucleation theory.« less

[Knowledge of emergency contraception among adolescents in public and private Brazilian high schools].

PubMed

Chofakian, Christiane Borges do Nascimento; Borges, Ana Luiza Vilela; Fujimori, Elizabeth; Hoga, Luiza Akiko Komura

2014-07-01

This study aimed to analyze the level of knowledge concerning emergency contraception among adolescents in public and private high schools. This was a cross-sectional study with 705 students 15 to 19 years of age enrolled in public and private high schools in a municipality in São Paulo State, Brazil. The authors used stratified probabilistic sampling by type of school and systematic sampling by class. Sexual initiation and use of emergency contraception were reported by 24.9% of private school students and 32% of public school students. The mean score on knowledge was 3.87 (SD = 2.12) in public schools and 5.14 (SD = 2.00) in private schools. Multiple linear regression analysis showed that higher scores on knowledge concerning emergency contraception were associated with: enrollment in private schools, female gender, older adolescents, sexual initiation, previous use of emergency contraception, and knowing someone who had used the method. The study concludes that few adolescents are properly informed about the method and that many harbor persistent misconceptions.

PCA3-based nomogram for predicting prostate cancer and high grade cancer on initial transrectal guided biopsy.

PubMed

Elshafei, Ahmed; Chevli, K Kent; Moussa, Ayman S; Kara, Onder; Chueh, Shih-Chieh; Walter, Peter; Hatem, Asmaa; Gao, Tianming; Jones, J Stephen; Duff, Michael

2015-12-01

To develop a validated prostate cancer antigen 3 (PCA3) based nomogram that predicts likelihood of overall prostate cancer (PCa) and intermediate/high grade prostate cancer (HGPCa) in men pursuing initial transrectal prostate biopsy (TRUS-PBx). Data were collected on 3,675 men with serum prostate specific antigen level (PSA) ≤ 20 ng/ml who underwent initial prostate biopsy with at least 10 cores sampling at time of the biopsy. Two logistic regression models were constructed to predict overall PCa and HGPCa incorporating age, race, family history (FH) of PCa, PSA at diagnosis, PCA3, total prostate volume (TPV), and digital rectal exam (DRE). One thousand six hundred twenty (44%) patients had biopsy confirmed PCa with 701 men (19.1%) showing HGPCa. Statistically significant predictors of overall PCa were age (P < 0.0001, OR. 1.51), PSA at diagnosis (P < 0.0001, OR.1.95), PCA3 (P < 0.0001, OR.3.06), TPV (P < 0.0001, OR.0.47), FH (P = 0.003, OR.1.32), and abnormal DRE (P = 0.001, OR. 1.32). While for HGPCa, predictors were age (P < 0.0001, OR.1.77), PSA (P < 0.0001, OR.2.73), PCA3 (P < 0.0001, OR.2.26), TPV (P < 0.0001, OR.0.4), and DRE (P < 0.0001, OR.1.53). Two nomograms were reconstructed for predicted overall PCa probability at time of initial biopsy with a concordance index of 0.742 (Fig. 1), and HGPCa with a concordance index of 0.768 (Fig. 2). Our internally validated initial biopsy PCA3 based nomogram is reconstructed based on a large dataset. The c-index indicates high predictive accuracy, especially for high grade PCa and improves the ability to predict biopsy outcomes. © 2015 Wiley Periodicals, Inc.

From the chromatin interaction network to the organization of the human genome into replication N/U-domains

NASA Astrophysics Data System (ADS)

Boulos, Rasha E.; Julienne, Hanna; Baker, Antoine; Chen, Chun-Long; Petryk, Nataliya; Kahli, Malik; dʼAubenton-Carafa, Yves; Goldar, Arach; Jensen, Pablo; Hyrien, Olivier; Thermes, Claude; Arneodo, Alain; Audit, Benjamin

2014-11-01

The three-dimensional (3D) architecture of the mammalian nucleus is now being unraveled thanks to the recent development of chromatin conformation capture (3C) technologies. Here we report the results of a combined multiscale analysis of genome-wide mean replication timing and chromatin conformation data that reveal some intimate relationships between chromatin folding and human DNA replication. We previously described megabase replication N/U-domains as mammalian multiorigin replication units, and showed that their borders are ‘master’ replication initiation zones that likely initiate cascades of origin firing responsible for the stereotypic replication of these domains. Here, we demonstrate that replication N/U-domains correspond to the structural domains of self-interacting chromatin, and that their borders act as insulating regions both in high-throughput 3C (Hi-C) data and high-resolution 3C (4C) experiments. Further analyses of Hi-C data using a graph-theoretical approach reveal that N/U-domain borders are long-distance, interconnected hubs of the chromatin interaction network. Overall, these results and the observation that a well-defined ordering of chromatin states exists from N/U-domain borders to centers suggest that ‘master’ replication initiation zones are at the heart of a high-order, epigenetically controlled 3D organization of the human genome.

Space Weathering Experiments on Spacecraft Materials

NASA Technical Reports Server (NTRS)

Cooper, R.; Cowardin, H.; Engelhar, D.; Plis, Elena; Hoffman, R.

2017-01-01

A project to investigate space environment effects on specific materials with interest to remote sensing was initiated in 2016. The goal of the project is to better characterize changes in the optical properties of polymers and Mylar, specifically those found in multi-layered spacecraft insulation, due to electron bombardment. Previous analysis shows that chemical bonds break and potentially reform when exposed to high energy electrons. Among other properties these chemical changes altered the optical reflectance as documented in laboratory analysis. This paper presents results of the initial experiment results focused on the exposure of materials to various fluences of high energy electrons, used to simulate a portion of the geosynchronous space environment. The paper illustrates how the spectral reflectance changes as a function of time on orbit with respect to GEO environmental factors and investigates the survivability of the material after multiple electron doses. These results provide a baseline for analysis of aging effects on satellite systems used for remote sensing. They also provide preliminary analysis on what materials are most likely to encompass the high area-to-mass population of space debris in the geosynchronous environment. Lastly, the paper provides the results of the initial experimentation as a proof of concept for space aging on polymers and Mylar for conducting more experiments with a larger subset of spacecraft materials.

Effects of carbon dioxide exposure on intensively cultured rainbow trout Oncorhynchus mykiss: Physiological responses and fillet attributes

USGS Publications Warehouse

Danley, M.L.; Kenney, P.B.; Mazik, P.M.; Kiser, R.; Hankins, J.A.

2005-01-01

Rainbow trout Oncorhynchus mykiss (261.6 ?? 24.7 g initial weight, mean ?? SEM) at 13.1 ?? 0.2 C were exposed for 94 d to one of three CO2 treatments: control (22.1 ?? 2.8 mg/L), medium (34.5 ?? 3.8 mg/L), or high (48.7 ?? 4.4 mg/L). Trout were checked daily for survival, and fish were sampled at 0, 28, 56, and 84 d for physiological responses, growth, and fillet quality assessments. Trout were also challenged to a 15-min crowding stress at 93 d to assess their ability to initiate a stress response during hypercapnia. Chronically exposed trout showed nearly 100% survival through 84 d exposure (1 of 1,500 fish died). Growth and physiological results showed that increasing elevated CO2 concentrations result in corresponding decreased growth rates and CO2-specific physiological parameters: The medium and high CO2 treatments had significantly slower growth and subsequently smaller fish by 84 d. Exposed trout also showed significantly (P < 0.05) decreased plasma chloride for medium and high CO2 treatments compared to the control from 28 through 84 d. Decreased growth and smaller fish in the medium and high CO2 treatments resulted in correspondingly smaller fresh and smoked fillet weights. Chronic CO2 exposure did not result in notable changes in ultimate muscle pH. Exposure to 15-min crowding stress at 93 d resulted in significant changes in hematocrit, plasma cortisol, glucose, and chloride for all treatment groups. CO2-specific changes were detected in hematocrit, plasma cortisol, and plasma chloride responses following the 15-min crowding stress. ?? Copyright by the World Aquaculture Society 2005.

Comparison of the microstructure, deformation and crack initiation behavior of austenitic stainless steel irradiated in-reactor or with protons

NASA Astrophysics Data System (ADS)

Stephenson, Kale J.; Was, Gary S.

2015-01-01

The objective of this study was to compare the microstructures, microchemistry, hardening, susceptibility to IASCC initiation, and deformation behavior resulting from proton or reactor irradiation. Two commercial purity and six high purity austenitic stainless steels with various solute element additions were compared. Samples of each alloy were irradiated in the BOR-60 fast reactor at 320 °C to doses between approximately 4 and 12 dpa or by a 3.2 MeV proton beam at 360 °C to a dose of 5.5 dpa. Irradiated microstructures consisted mainly of dislocation loops, which were similar in size but lower in density after proton irradiation. Both irradiation types resulted in the formation of Ni-Si rich precipitates in a high purity alloy with added Si, but several other high purity neutron irradiated alloys showed precipitation that was not observed after proton irradiation, likely due to their higher irradiation dose. Low densities of small voids were observed in several high purity proton irradiated alloys, and even lower densities in neutron irradiated alloys, implying void nucleation was in process. Elemental segregation at grain boundaries was very similar after each irradiation type. Constant extension rate tensile experiments on the alloys in simulated light water reactor environments showed excellent agreement in terms of the relative amounts of intergranular cracking, and an analysis of localized deformation after straining showed a similar response of cracking to surface step height after both irradiation types. Overall, excellent agreement was observed after proton and reactor irradiation, providing additional evidence that proton irradiation is a useful tool for accelerated testing of irradiation effects in austenitic stainless steel.

Experiments of thermomechanical fatigue of SMAs

NASA Astrophysics Data System (ADS)

Lagoudas, Dimitris C.; Miller, David A.

1999-07-01

As SMA wires are gaining in popularity for use as actuators, one constitutive parameter that remain unknown is the thermomechanical fatigue life. Even though the effect of thermal cycles on the transformation characteristics of SMAs has been studied, these teste have not been extended to high number of cycles. In this study, a novel test frame developed to study the thermomechanical fatigue life of SMAs is described. Additionally, a testing protocol is discussed necessary to fully establish the fatigue characteristics of SMAs under various conditions. Initial results of the initial test show a substantial increase in the number of cycles to failure as the applied stress level reduces to approximately 100 MPa.

Rich structure in the correlation matrix spectra in non-equilibrium steady states

NASA Astrophysics Data System (ADS)

Biswas, Soham; Leyvraz, Francois; Monroy Castillero, Paulino; Seligman, Thomas H.

2017-01-01

It has been shown that, if a model displays long-range (power-law) spatial correlations, its equal-time correlation matrix will also have a power law tail in the distribution of its high-lying eigenvalues. The purpose of this paper is to show that the converse is generally incorrect: a power-law tail in the high-lying eigenvalues of the correlation matrix may exist even in the absence of equal-time power law correlations in the initial model. We may therefore view the study of the eigenvalue distribution of the correlation matrix as a more powerful tool than the study of spatial Correlations, one which may in fact uncover structure, that would otherwise not be apparent. Specifically, we show that in the Totally Asymmetric Simple Exclusion Process, whereas there are no clearly visible correlations in the steady state, the eigenvalues of its correlation matrix exhibit a rich structure which we describe in detail.

Development of a New De Novo Design Algorithm for Exploring Chemical Space.

PubMed

Mishima, Kazuaki; Kaneko, Hiromasa; Funatsu, Kimito

2014-12-01

In the first stage of development of new drugs, various lead compounds with high activity are required. To design such compounds, we focus on chemical space defined by structural descriptors. New compounds close to areas where highly active compounds exist will show the same degree of activity. We have developed a new de novo design system to search a target area in chemical space. First, highly active compounds are manually selected as initial seeds. Then, the seeds are entered into our system, and structures slightly different from the seeds are generated and pooled. Next, seeds are selected from the new structure pool based on the distance from target coordinates on the map. To test the algorithm, we used two datasets of ligand binding affinity and showed that the proposed generator could produce diverse virtual compounds that had high activity in docking simulations. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Generation of cavitation luminescence by laser-induced exothermic chemical reaction

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

Jung Park, Han; Diebold, Gerald J.

2013-08-14

Absorption of high power laser radiation by aqueous carbon suspensions is known to result in the formation of highly compressed bubbles of hydrogen and carbon monoxide through the endothermic carbon-steam reaction. The bubbles expand rapidly, overreaching their equilibrium diameter, and then collapse tens to hundreds of microseconds after formation to give a flash of radiation. Here we report on the effects of laser-initiated exothermic chemical reaction on cavitation luminescence. Experiments with hydrogen peroxide added to colloidal carbon suspensions show that both the time of the light flash following the laser pulse and the intensity of luminescence increase with hydrogen peroxidemore » concentration, indicating that large, highly energetic gas bubbles are produced. Additional experiments with colloidal carbon suspensions show the effects of high pressure on the luminescent intensity and its time of appearance following firing of the laser.« less

Phase stability and microstructures of high entropy alloys ion irradiated to high doses

NASA Astrophysics Data System (ADS)

Xia, Songqin; Gao, Michael C.; Yang, Tengfei; Liaw, Peter K.; Zhang, Yong

2016-11-01

The microstructures of AlxCoCrFeNi (x = 0.1, 0.75 and 1.5 in molar ratio) high entropy alloys (HEAs) irradiated at room temperature with 3 MeV Au ions at the highest fluence of 105, 91, and 81 displacement per atom, respectively, were studied. Transmission electron microscopy (TEM) and high-resolution TEM (HRTEM) analyses show that the initial microstructures and phase composition of all three alloys are retained after ion irradiation and no phase decomposition is observed. Furthermore, it is demonstrated that the disordered face-centered cubic (FCC) and disordered body-centered cubic (BCC) phases show much less defect cluster formation and structural damage than the NiAl-type ordered B2 phase. This effect is explained by higher entropy of mixing, higher defect formation/migration energies, substantially lower thermal conductivity, and higher atomic level stress in the disordered phases.

Rich structure in the correlation matrix spectra in non-equilibrium steady states.

PubMed

Biswas, Soham; Leyvraz, Francois; Monroy Castillero, Paulino; Seligman, Thomas H

2017-01-17

It has been shown that, if a model displays long-range (power-law) spatial correlations, its equal-time correlation matrix will also have a power law tail in the distribution of its high-lying eigenvalues. The purpose of this paper is to show that the converse is generally incorrect: a power-law tail in the high-lying eigenvalues of the correlation matrix may exist even in the absence of equal-time power law correlations in the initial model. We may therefore view the study of the eigenvalue distribution of the correlation matrix as a more powerful tool than the study of spatial Correlations, one which may in fact uncover structure, that would otherwise not be apparent. Specifically, we show that in the Totally Asymmetric Simple Exclusion Process, whereas there are no clearly visible correlations in the steady state, the eigenvalues of its correlation matrix exhibit a rich structure which we describe in detail.

Effect of initiator concentration to low-density polyethylene production in a tubular reactor

NASA Astrophysics Data System (ADS)

Azmi, A.; Aziz, N.

2016-11-01

Low-density polyethylene (LDPE) is one of the most widely used polymers in the world, which is produced in high-capacity tubular and autoclave reactors. As the LDPE industry turn into more competitive and its market profit margins become tighter, manufacturers have to develop solutions to debottleneck the reactor output while abiding to the stringent product specification. A single polyolefin plant producing ten to forty grades of LDPE with various melt flow index (MFI), therefore understanding the reaction mechanism, the operating conditions as well as the dynamic behavior of tubular reactor is essential before any improvement can take place. In the present work, a steady state mathematical model representing a tubular reactor for the production of LDPE is simulated using MATLAB R2015a®. The model developed is a function of feed inlet, reactor jacket, single initiator injector and outlet stream. Analysis on the effect of initiator concentration (CI) shows sudden declining trend of initiator's concentration which indicates that all of the initiators are exhausted after polymerization reaction and no further reaction occur from this point onwards. Furthermore, the results demonstrate that the concentration of initiator gives significant impact on reactor temperature's profile and monomer conversion rate, since higher initiator concentration promotes greater polymerization rate, and therefore leads to higher monomer conversion throughput.

The Subiculum: A Potential Site of Ictogenesis in a Neonatal Seizure Model

PubMed Central

Wang, Xin-Xin; Li, Yong-Hua; Gong, Hai-Qing; Liang, Pei-Ji; Zhang, Pu-Ming; Lu, Qin-Chi

2017-01-01

Studies have reported that the subiculum is one origin of interictal-like discharges in adult patients with temporal lobe epilepsy; however, whether the subiculum represents a site of ictogenesis for neonatal seizures remains unclear. In this study, multi-electrode recording techniques were used to record epileptiform discharges induced by low-Mg2+ or high-K+ artificial cerebrospinal fluid in neonatal mouse hippocampal slices, and the spatiotemporal dynamics of the epileptiform discharges were analyzed. The Na+–K+–2Cl− cotransporter 1 (NKCC1) blocker, bumetanide, was applied to test its effect upon epileptiform discharges in low-Mg2+ model. The effect of N-methyl-d-aspartate receptors (NMDARs) antagonist, d-AP5, upon the epileptiform discharges in high-K+ model was examined. We found that the neonatal subiculum not only relayed epileptiform discharges emanating from the hippocampus proper (HP) but also initiated epileptiform discharges (interictal- and ictal-like discharges) independently. The latency to onset of the first epileptiform discharge initiated in the subiculum was similar to that initiated in the HP. Bumetanide efficiently blocked seizures in the neonatal HP, but was less effectively in suppressing seizures initiated in the subiculum. In high-K+ model, d-AP5 was more effective in blocking seizures initiated in the subiculum than that initiated in the HP. Furthermore, Western blotting analysis showed that NKCC1 expression was lower in the subiculum than that in the HP, whereas the expression of NMDAR subunits, NR2A and NR2B, was higher in the subiculum than that in the HP. Our results revealed that the subiculum was a potential site of ictogenesis in neonatal seizures and possessed similar seizure susceptibility to the HP. GABAergic excitation resulting from NKCC1 may play a less dominant role during ictogenesis in the subiculum than that in the HP. The subicular ictogenesis may be related to the glutamatergic excitation mediated by NMDARs. PMID:28473802

Genome-wide identification and characterisation of human DNA replication origins by initiation site sequencing (ini-seq)

PubMed Central

Langley, Alexander R.; Gräf, Stefan; Smith, James C.; Krude, Torsten

2016-01-01

Next-generation sequencing has enabled the genome-wide identification of human DNA replication origins. However, different approaches to mapping replication origins, namely (i) sequencing isolated small nascent DNA strands (SNS-seq); (ii) sequencing replication bubbles (bubble-seq) and (iii) sequencing Okazaki fragments (OK-seq), show only limited concordance. To address this controversy, we describe here an independent high-resolution origin mapping technique that we call initiation site sequencing (ini-seq). In this approach, newly replicated DNA is directly labelled with digoxigenin-dUTP near the sites of its initiation in a cell-free system. The labelled DNA is then immunoprecipitated and genomic locations are determined by DNA sequencing. Using this technique we identify >25,000 discrete origin sites at sub-kilobase resolution on the human genome, with high concordance between biological replicates. Most activated origins identified by ini-seq are found at transcriptional start sites and contain G-quadruplex (G4) motifs. They tend to cluster in early-replicating domains, providing a correlation between early replication timing and local density of activated origins. Origins identified by ini-seq show highest concordance with sites identified by SNS-seq, followed by OK-seq and bubble-seq. Furthermore, germline origins identified by positive nucleotide distribution skew jumps overlap with origins identified by ini-seq and OK-seq more frequently and more specifically than do sites identified by either SNS-seq or bubble-seq. PMID:27587586

Genome-wide identification and characterisation of human DNA replication origins by initiation site sequencing (ini-seq).

PubMed

Langley, Alexander R; Gräf, Stefan; Smith, James C; Krude, Torsten

2016-12-01

Next-generation sequencing has enabled the genome-wide identification of human DNA replication origins. However, different approaches to mapping replication origins, namely (i) sequencing isolated small nascent DNA strands (SNS-seq); (ii) sequencing replication bubbles (bubble-seq) and (iii) sequencing Okazaki fragments (OK-seq), show only limited concordance. To address this controversy, we describe here an independent high-resolution origin mapping technique that we call initiation site sequencing (ini-seq). In this approach, newly replicated DNA is directly labelled with digoxigenin-dUTP near the sites of its initiation in a cell-free system. The labelled DNA is then immunoprecipitated and genomic locations are determined by DNA sequencing. Using this technique we identify >25,000 discrete origin sites at sub-kilobase resolution on the human genome, with high concordance between biological replicates. Most activated origins identified by ini-seq are found at transcriptional start sites and contain G-quadruplex (G4) motifs. They tend to cluster in early-replicating domains, providing a correlation between early replication timing and local density of activated origins. Origins identified by ini-seq show highest concordance with sites identified by SNS-seq, followed by OK-seq and bubble-seq. Furthermore, germline origins identified by positive nucleotide distribution skew jumps overlap with origins identified by ini-seq and OK-seq more frequently and more specifically than do sites identified by either SNS-seq or bubble-seq. © The Author(s) 2016. Published by Oxford University Press on behalf of Nucleic Acids Research.

Characterizing meteorological and hydrologic conditions associated with shallow landslide initiation in the coastal bluffs of the Atlantic Highlands, New Jersey

USGS Publications Warehouse

Ashland, Francis; Fiore, Alex R.; Reilly, Pamela A.; De Graff, Jerome V.; Shakoor, Abdul

2017-01-01

Meteorological and hydrologic conditions associated with shallow landslide initiation in the coastal bluffs of the Atlantic Highlands, New Jersey remain undocumented despite a history of damaging slope movement extending back to at least 1903. This study applies an empirical approach to quantify the rainfall conditions leading to shallow landsliding based on analysis of overlapping historical precipitation data and records of landslide occurrence, and uses continuous monitoring to quantify antecedent soil moisture and hydrologic response to rainfall events at two failure-prone hillslopes. Analysis of historical rainfall data reveals that both extended duration and cumulative rainfall amounts are critical characteristics of many landslide-inducing storms, and is consistent with current monitoring results that show notable increases in shallow soil moisture and pore-water pressure in continuous rainfall periods. Monitoring results show that shallow groundwater levels and soil moisture increase from annual lows in late summer-early fall to annual highs in late winter-early spring, and historical data indicate that shallow landslides occur most commonly from tropical cyclones in late summer through fall and nor’easters in spring. Based on this seasonality, we derived two provisional rainfall thresholds using a limited dataset of documented landslides and rainfall conditions for each season and storm type. A lower threshold for landslide initiation in spring corresponds with high antecedent moisture conditions, and higher rainfall amounts are required to induce shallow landslides during the drier soil moisture conditions in late summer-early fall.

High-visibility time-bin entanglement for testing chained Bell inequalities

NASA Astrophysics Data System (ADS)

Tomasin, Marco; Mantoan, Elia; Jogenfors, Jonathan; Vallone, Giuseppe; Larsson, Jan-Åke; Villoresi, Paolo

2017-03-01

The violation of Bell's inequality requires a well-designed experiment to validate the result. In experiments using energy-time and time-bin entanglement, initially proposed by Franson in 1989, there is an intrinsic loophole due to the high postselection. To obtain a violation in this type of experiment, a chained Bell inequality must be used. However, the local realism bound requires a high visibility in excess of 94.63% in the time-bin entangled state. In this work, we show how such a high visibility can be reached in order to violate a chained Bell inequality with six, eight, and ten terms.

Transparent hydrogel with enhanced water retention capacity by introducing highly hydratable salt

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

Bai, Yuanyuan; Xiang, Feng; Wang, Hong, E-mail: hwang@mail.xjtu.edu.cn, E-mail: suo@seas.harvard.edu

2014-10-13

Polyacrylamide hydrogels containing salt as electrolyte have been used as highly stretchable transparent electrodes in flexible electronics, but those hydrogels are easy to dry out due to water evaporation. Targeted, we try to enhance water retention capacity of polyacrylamide hydrogel by introducing highly hydratable salts into the hydrogel. These hydrogels show enhanced water retention capacity in different level. Specially, polyacrylamide hydrogel containing high content of lithium chloride can retain over 70% of its initial water even in environment with relative humidity of only 10% RH. The excellent water retention capacities of these hydrogels will make more applications of hydrogels becomemore » possible.« less

Microfluidics separation reveals the stem-cell-like deformability of tumor-initiating cells.

PubMed

Zhang, Weijia; Kai, Kazuharu; Choi, Dong Soon; Iwamoto, Takayuki; Nguyen, Yen H; Wong, Helen; Landis, Melissa D; Ueno, Naoto T; Chang, Jenny; Qin, Lidong

2012-11-13

Here we report a microfluidics method to enrich physically deformable cells by mechanical manipulation through artificial microbarriers. Driven by hydrodynamic forces, flexible cells or cells with high metastatic propensity change shape to pass through the microbarriers and exit the separation device, whereas stiff cells remain trapped. We demonstrate the separation of (i) a mixture of two breast cancer cell types (MDA-MB-436 and MCF-7) with distinct deformabilities and metastatic potentials, and (ii) a heterogeneous breast cancer cell line (SUM149), into enriched flexible and stiff subpopulations. We show that the flexible phenotype is associated with overexpression of multiple genes involved in cancer cell motility and metastasis, and greater mammosphere formation efficiency. Our observations support the relationship between tumor-initiating capacity and cell deformability, and demonstrate that tumor-initiating cells are less differentiated in terms of cell biomechanics.

Self-pressurization of a flightweight liquid hydrogen storage tank subjected to low heat flux

NASA Technical Reports Server (NTRS)

Hasan, M. M.; Lin, C. S.; Vandresar, N. T.

1991-01-01

Results are presented for an experimental investigation of self-pressurization and thermal stratification of a 4.89 cu m liquid hydrogen (LH2) storage tank subjected to low heat flux (0.35, 2.0, and 3.5 W/sq m) under normal gravity conditions. Tests were performed at fill levels of 83 to 84 percent (by volume). The LH2 tank was representative of future spacecraft tankage, having a low mass-to-volume ratio and high performance multilayer thermal insulation. Results show that the pressure rise rate and thermal stratification increase with increasing heat flux. At the lowest heat flux, the pressure rise rate is comparable to the homogenous rate, while at the highest heat flux, the rate is more than three times the homogeneous rate. It was found that initial conditions have a significant impact on the initial pressure rise rate. The quasi-steady pressure rise rates are nearly independent of the initial condition after an initial transient period has passed.

Studying the effect of material initial conditions on drying induced stresses

NASA Astrophysics Data System (ADS)

Heydari, M.; Khalili, K.; Ahmadi-Brooghani, S. Y.

2018-02-01

Cracking as a result of non-uniform deformation during drying is one of defects that may occur during drying and has to be dealt with by proper drying treatment. In the current study the effect of initial condition has been investigated on stress-strain induced by drying. The convective drying of a porous clay-like material has been simulated by using a mathematical model. Mass and heat transfer along with the mechanical behavior of the object being dried make the phenomenon a highly coupled problem. The coupling variables are the solid displacement, moisture content and temperature of the porous medium. A numerical solution is sought and employed to predict the influence of initial conditions of material on the drying induced stresses, the moisture content, and the temperature variations. Simulation results showed that increasing the initial temperature is an effective way to reduce the stresses induced by drying and to obtain products with good quality without significant change in drying curve and in comparison this is more effective than intermittent drying.

Effects of {10-12} Twins on Dynamic Torsional Properties of Extruded AZ31 Magnesium Alloy

NASA Astrophysics Data System (ADS)

Lee, Jong Un; Song, Seok Weon; Kim, Yongjin; Kim, Sang-Hoon; Kim, Ye Jin; Park, Sung Hyuk

2018-03-01

Effects of initial twins on dynamic torsional properties of extruded AZ31 alloy were investigated by introducing {10-12} twins into it through precompression to 3 and 6% strains along the extrusion direction and performing torsional testing at a strain rate of 1.4 × 103 s-1 using a torsional Kolsky bar system. The as-extruded sample without twins showed higher dynamic torsional properties than the precompressed samples with many initial twins; the maximum shear strength and fracture shear strain decreased with increasing amount of initial twins. In the as-extruded sample, twinning occurred vigorously throughout the gage section of the tubular specimen during high-strain-rate torsional tests, resulting in heavily deformed morphology, many macrocracks, and rough fractured surfaces. The increased amount of initial twins suppressed the twinning behavior and localized the applied torsional deformation; this resulted in an almost unchanged sample shape, no secondary cracks, and a flat fracture plane, thereby deteriorating the dynamic torsional properties of the extruded alloy.

Geometric scaling behavior of the scattering amplitude for DIS with nuclei

NASA Astrophysics Data System (ADS)

Kormilitzin, Andrey; Levin, Eugene; Tapia, Sebastian

2011-12-01

The main question, that we answer in this paper, is whether the initial condition can influence on the geometric scaling behavior of the amplitude for DIS at high energy. We re-write the non-linear Balitsky-Kovchegov equation in the form which is useful for treating the interaction with nuclei. Using the simplified BFKL kernel, we find the analytical solution to this equation with the initial condition given by the McLerran-Venugopalan formula. This solution does not show the geometric scaling behavior of the amplitude deeply in the saturation region. On the other hand, the BFKL Pomeron calculus with the initial condition at x=1/mR given by the solution to Balitsky-Kovchegov equation, leads to the geometric scaling behavior. The McLerran-Venugopalan formula is the natural initial condition for the Color Glass Condensate (CGC) approach. Therefore, our result gives a possibility to check experimentally which approach: CGC or BFKL Pomeron calculus, is more satisfactory.

Live-cell analysis of endogenous GFP-RPB1 uncovers rapid turnover of initiating and promoter-paused RNA Polymerase II.

PubMed

Steurer, Barbara; Janssens, Roel C; Geverts, Bart; Geijer, Marit E; Wienholz, Franziska; Theil, Arjan F; Chang, Jiang; Dealy, Shannon; Pothof, Joris; van Cappellen, Wiggert A; Houtsmuller, Adriaan B; Marteijn, Jurgen A

2018-05-08

Initiation and promoter-proximal pausing are key regulatory steps of RNA Polymerase II (Pol II) transcription. To study the in vivo dynamics of endogenous Pol II during these steps, we generated fully functional GFP-RPB1 knockin cells. GFP-RPB1 photobleaching combined with computational modeling revealed four kinetically distinct Pol II fractions and showed that on average 7% of Pol II are freely diffusing, while 10% are chromatin-bound for 2.4 seconds during initiation, and 23% are promoter-paused for only 42 seconds. This unexpectedly high turnover of Pol II at promoters is most likely caused by premature termination of initiating and promoter-paused Pol II and is in sharp contrast to the 23 minutes that elongating Pol II resides on chromatin. Our live-cell-imaging approach provides insights into Pol II dynamics and suggests that the continuous release and reinitiation of promoter-bound Pol II is an important component of transcriptional regulation. Copyright © 2018 the Author(s). Published by PNAS.

Inequality and visibility of wealth in experimental social networks.

PubMed

Nishi, Akihiro; Shirado, Hirokazu; Rand, David G; Christakis, Nicholas A

2015-10-15

Humans prefer relatively equal distributions of resources, yet societies have varying degrees of economic inequality. To investigate some of the possible determinants and consequences of inequality, here we perform experiments involving a networked public goods game in which subjects interact and gain or lose wealth. Subjects (n = 1,462) were randomly assigned to have higher or lower initial endowments, and were embedded within social networks with three levels of economic inequality (Gini coefficient = 0.0, 0.2, and 0.4). In addition, we manipulated the visibility of the wealth of network neighbours. We show that wealth visibility facilitates the downstream consequences of initial inequality-in initially more unequal situations, wealth visibility leads to greater inequality than when wealth is invisible. This result reflects a heterogeneous response to visibility in richer versus poorer subjects. We also find that making wealth visible has adverse welfare consequences, yielding lower levels of overall cooperation, inter-connectedness, and wealth. High initial levels of economic inequality alone, however, have relatively few deleterious welfare effects.

Chromate conversion coating: Iridite 14-2 thermal/optical characterization

NASA Astrophysics Data System (ADS)

Rodriguez, Marcello

2012-10-01

Chromate Conversion Coating (CCC) BOL and EOL thermal properties (absorptance and emittance) have been unspecified throughout the industry and throughout its use here at GSFC. Being key values essential for thermal engineers to assess thermal space conditions, this study focuses on the current application process, its outputted properties and assess whether these properties can in turn be classified under proper documentation. The results show that wide variations in the process overcome any possibility in thermally classifying this coating. A new set of samples were fabricated (in preparation for space environmental studies) in which a more controlled approach to applying the CCC was made. The resulting thermal values continued to show variations indicating lack of bath agitation existing within the bath. From this study you can conclude that witness samples may not best represent the flight hardware for this coating. The study then turns to space environmental study testing samples to high temperature (80°C), high vacuum, and combination of both, and UV radiation totaling 1625 ESH. The results showed an extremely dynamic coating sensitive to every environmental condition it was exposed to. Though the initial changes to the coating are drastic, post initial changes appear to be minuscule making EOL predictions more attainable. These results show that the worst case alpha/emittance values are likely after ground processing and before space exposure. From the data obtained in this study greater understanding and more informed decisions can be made with respect to this coating.

The development and initial validation of a sensitive bedside cognitive screening test.

PubMed

Faust, D; Fogel, B S

1989-01-01

Brief bedside cognitive examinations such as the Mini-Mental State Examination are designed to detect delirium and dementia but not more subtle or delineated cognitive deficits. Formal neuropsychological evaluation provides greater sensitivity and detects a wider range of cognitive deficits but is too lengthy for efficient use at the bedside or in epidemiological studies. The authors developed the High Sensitivity Cognitive Screen (HSCS), a 20-minute interview-based test, to identify patients who show disorder on formal neuropsychological evaluation. An initial study demonstrated satisfactory test-retest and interrater reliability. The HSCS was then administered to 60 psychiatric and neurological patients with suspected cognitive deficits but without gross impairment, who also completed formal neuropsychological testing. Results of both tests were independently classified as either normal, borderline, or abnormal. The HSCS correctly classified 93% of patients across the normal-abnormal dichotomy and showed promise for characterizing the extent and severity of cognitive dysfunction.

Flower choice by naïve young crab spiders and the effect of subsequent experience.

PubMed

Morse

2000-05-01

Initial responses of naïve individuals to critical environmental stimuli provide important information about the innate contribution to behaviour, and subsequent responses to the same stimuli may show the role of experience in mediating those initial responses. To test the role of these factors, I measured initial patch choices and giving-up responses of just-emerged, naïve, second-instar crab spiders, Misumena vatia, on several hunting sites they encountered after leaving their natal nests. In follow-up tests I measured the effects of these experiences on subsequent patch choice decisions. The choice of hunting sites is a vital decision at all stages of the life cycle for sit-and-wait predators such as Misumena. In their initial tests these spiderlings remained more frequently on goldenrod (Solidago spp.) flowers than on green or yellow goldenrod buds, a preference they retained through tests run on 5 consecutive days. Individuals on green and yellow buds shifted sites more quickly and frequently than those from flowers, and made most of these moves to flowers, which attracted many more prey than did buds. These differences were not affected by age, energetic condition, or loss of information over the period of the experiment. Once spiderlings moved from buds, they showed a high, increasing tendency to move from buds in subsequent runs, those from flowers showed a consistently low tendency. These results suggest that spiderlings retain their innate behavioural patterns through the second instar, but that experience also plays a modest role in patch choice at this stage. Copyright 2000 The Association for the Study of Animal Behaviour.

Developing a Small-scale De-fluoridation Filter for use in Rural Northern Ghana with Activated Alumina as the Sorbent

NASA Astrophysics Data System (ADS)

Craig, L.; Stillings, L. L.; Decker, D.; Thomas, J.

2013-12-01

In northern Ghana, groundwater is the main source of household water and is generally considered a safe and economical source of drinking water. However in some areas it contains fluoride (F-) concentrations above the 1.5 ppm limit recommended by the World Health Organization, putting the users at risk of fluorosis. The study area in the Upper East Region of northern Ghana has pockets of groundwater F- up to 4.6 ppm and, as a result, also has a high percentage of residents with dental fluorosis. They have no alternative water source and, because of the poverty and limited access to technology, the affected community lacks the capacity to set up advanced treatment systems. One proposed solution is to attach F- adsorption filters to the wells, since adsorption is considered a simple and cost effective approach for treating high F- drinking water. This study evaluates activated alumina as a sorbent for use in de-fluoridation filters in the study area. We evaluated the long-term adsorption capacity of activated alumina, as well as potential changes in F- adsorption rate and capacity with grain size. We measured differences in positive surface charge (as C m-2) via slow acid titration, as well as F- loading with varied prior hydration time. Experimental results from this research show no notable change in F- adsorption or positive surface charge when the activated alumina surface was pre-equilibrated in distilled water from 24 hours up to 30 weeks before the experiment. The results of F- loading show a maximum of ~3.4 mg F- sorbed per gm activated alumina (at initial pH ~6.9, initial F- 1 to 60 ppm, and 20 hr reaction time). The pH dependent surface charge shows a maximum of ~0.14 C m-2 at pH of ~4.4 and zero surface charge at pH ~8.5. F- loading experiments were conducted with grain size ranges 0.125 to 0.250 mm and 0.5 to 1.0 mm to evaluate changes in F- adsorption rate (initial pH ~6.9, initial F- 10 ppm) and F- loading (initial pH ~6.9, initial F- 1 to 60 ppm, 20 hr reaction time). The F- loading onto activated alumina did not change with grain size. However time to equilibrium increased dramatically with a decrease in grain size - after one hour of reaction time, the larger grain size adsorbed only 59% of F-, while at the finer grain size 90% was adsorbed. Future work will determine the volume of high F- water that can be treated before activated alumina needs to be regenerated or changed. These data will be incorporated into the design of a small-scale F-1 adsorption filter in the study area, and will predict the longevity of activated alumina as the sorbent.

Cyclic stress effect on stress corrosion cracking of duplex stainless steel in chloride and caustic solutions

NASA Astrophysics Data System (ADS)

Yang, Di

Duplex stainless steel (DSS) is a dual-phase material with approximately equal volume amount of austenite and ferrite. It has both great mechanical properties (good ductility and high tensile/fatigue strength) and excellent corrosion resistance due to the mixture of the two phases. Cyclic loadings with high stress level and low frequency are experienced by many structures. However, the existing study on corrosion fatigue (CF) study of various metallic materials has mainly concentrated on relatively high frequency range. No systematic study has been done to understand the ultra-low frequency (˜10-5 Hz) cyclic loading effect on stress corrosion cracking (SCC) of DSSs. In this study, the ultra-low frequency cyclic loading effect on SCC of DSS 2205 was studied in acidified sodium chloride and caustic white liquor (WL) solutions. The research work focused on the environmental effect on SCC of DSS 2205, the cyclic stress effect on strain accumulation behavior of DSS 2205, and the combined environmental and cyclic stress effect on the stress corrosion crack initiation of DSS 2205 in the above environments. Potentiodynamic polarization tests were performed to investigate the electrochemical behavior of DSS 2205 in acidic NaCl solution. Series of slow strain rate tests (SSRTs) at different applied potential values were conducted to reveal the optimum applied potential value for SCC to happen. Room temperature static and cyclic creep tests were performed in air to illustrate the strain accumulation effect of cyclic stresses. Test results showed that cyclic loading could enhance strain accumulation in DSS 2205 compared to static loading. Moreover, the strain accumulation behavior of DSS 2205 was found to be controlled by the two phases of DSS 2205 with different crystal structures. The B.C.C. ferrite phase enhanced strain accumulation due to extensive cross-slips of the dislocations, whereas the F.C.C. austenite phase resisted strain accumulation due to cyclic strain hardening. Cyclic SSRTs were performed under the conditions that SCC occurs in sodium chloride and WL solutions. Test results show that cyclic stress facilitated crack initiations in DSS 2205. Stress corrosion cracks initiated from the intermetallic precipitates in acidic chloride environment, and the cracks initiated from austenite phase in WL environment. Cold-working has been found to retard the crack initiations induced by cyclic stresses.

Active learning of geometrical optics in high school: the ALOP approach

NASA Astrophysics Data System (ADS)

Alborch, Alejandra; Pandiella, Susana; Benegas, Julio

2017-09-01

A group comparison experiment of two high school classes with pre and post instruction testing has been carried out to study the suitability and advantages of using the active learning of optics and photonics (ALOP) curricula in high schools of developing countries. Two parallel, mixed gender, 12th grade classes of a high school run by the local university were chosen. One course was randomly selected to follow the experimental instruction, based on teacher and student activities contained in the ALOP Manual. The other course followed the traditional, teacher-centered, instruction previously practiced. Conceptual knowledge of the characteristics of image formation by plane mirrors and single convergent and divergent lenses was measured by applying, in both courses, the multiple-choice test, light and optics conceptual evaluation (LOCE). Measurement before instruction showed that initial knowledge was almost null, and therefore equivalent, in both courses. After instruction testing showed that the conceptual knowledge of students following the ALOP curricula more than doubled that achieved by students in the control course, a situation maintained throughout the six conceptual dimensions tested by the 34 questions of the LOCE test used in this experiment. Using a 60% performance level on the LOCE test as the threshold of satisfactory performance, most (about 90%) of the experimental group achieved this level—independent of initial knowledge, while no student following traditional instruction reached this level of understanding. Some considerations and recommendations for prospective users are also included.

Religious Involvement and Children's Well-Being: What Research Tells Us (And What It Doesn't). Child Trends Research Brief.

ERIC Educational Resources Information Center

Bridges, Lisa J.; Moore, Kristin Anderson

Noting national survey data from the past three decades showing consistently that more than 60 percent of American high school seniors agree that religion is important to them, and in light of increased interest in faith-based initiatives, this research brief summarizes findings from recent studies that examine linkages between adolescents beliefs…

Foliar nitrogen content and tree growth after prescribed fire in ponderosa pine.

Treesearch

J.D. Landsberg; P.H. Cochran; M.M. Finck; R.E. Martin

1984-01-01

This initial study of prescribed burning in ponderosa pine (Pinus ponderosa Doug. ex Laws.) stands in central Oregon showed that all periodic annual growth increments were reduced for trees alive four growing seasons later. Height growth was reduced 8 percent in areas burned by fires with moderate fuel consumption and 18 percent in areas with high...

JPRS Report, Science & Technology, USSR: Chemistry.

DTIC Science & Technology

1987-07-29

allowing these mycotoxins to be determined with high sensitivity in the food products most frequently contami- nated by them. The content of these...first ultraviolet and infrared spectrometers, then came, the turn of nuclear magnetic resonance, electron spin resonance and mass spectrometers...products was by two methods: gravimetric analysis and infrared spectrometry. Calculations showed that the energy necessary to disperse the initial

Tree production in desert regions using effluent and water harvesting

Treesearch

Martin M. Karpiscak; Gerald J. Gottfried

2000-01-01

Treated municipal effluent combined with water harvesting can be used for land restoration and enhancing the growth of important riparian tree species. Paired studies in Arizona are assessing the potential of growing trees using mixtures of effluent and potable water. Trees are grown in the field and in containers. Initial results from the field show high survival for...

Impact of Individual Differences on Reliance Optimization

DTIC Science & Technology

2016-05-31

Research Laboratory developed methodologies and configurations of an RPA simulation to support experimental studies that were collected at partner...that influence reliance on automation. Additionally, this research extended the study of Szalma and Taylor (2011) that showed personality traits...individuals attracted to video gaming have high initial spatial ability, for example. Experimental studies have examined directly the effect of training on

The Effects of Face Expertise Training on the Behavioral Performance and Brain Activity of Adults with High Functioning Autism Spectrum Disorders

ERIC Educational Resources Information Center

Faja, Susan; Webb, Sara Jane; Jones, Emily; Merkle, Kristen; Kamara, Dana; Bavaro, Joshua; Aylward, Elizabeth; Dawson, Geraldine

2012-01-01

The effect of expertise training with faces was studied in adults with ASD who showed initial impairment in face recognition. Participants were randomly assigned to a computerized training program involving either faces or houses. Pre- and post-testing included standardized and experimental measures of behavior and event-related brain potentials…

Geometric flow control of shear bands by suppression of viscous sliding

PubMed Central

Viswanathan, Koushik; Mahato, Anirban; Sundaram, Narayan K.; M'Saoubi, Rachid; Trumble, Kevin P.; Chandrasekar, Srinivasan

2016-01-01

Shear banding is a plastic flow instability with highly undesirable consequences for metals processing. While band characteristics have been well studied, general methods to control shear bands are presently lacking. Here, we use high-speed imaging and micro-marker analysis of flow in cutting to reveal the common fundamental mechanism underlying shear banding in metals. The flow unfolds in two distinct phases: an initiation phase followed by a viscous sliding phase in which most of the straining occurs. We show that the second sliding phase is well described by a simple model of two identical fluids being sheared across their interface. The equivalent shear band viscosity computed by fitting the model to experimental displacement profiles is very close in value to typical liquid metal viscosities. The observation of similar displacement profiles across different metals shows that specific microstructure details do not affect the second phase. This also suggests that the principal role of the initiation phase is to generate a weak interface that is susceptible to localized deformation. Importantly, by constraining the sliding phase, we demonstrate a material-agnostic method—passive geometric flow control—that effects complete band suppression in systems which otherwise fail via shear banding. PMID:27616920

Geometric flow control of shear bands by suppression of viscous sliding

NASA Astrophysics Data System (ADS)

Sagapuram, Dinakar; Viswanathan, Koushik; Mahato, Anirban; Sundaram, Narayan K.; M'Saoubi, Rachid; Trumble, Kevin P.; Chandrasekar, Srinivasan

2016-08-01

Shear banding is a plastic flow instability with highly undesirable consequences for metals processing. While band characteristics have been well studied, general methods to control shear bands are presently lacking. Here, we use high-speed imaging and micro-marker analysis of flow in cutting to reveal the common fundamental mechanism underlying shear banding in metals. The flow unfolds in two distinct phases: an initiation phase followed by a viscous sliding phase in which most of the straining occurs. We show that the second sliding phase is well described by a simple model of two identical fluids being sheared across their interface. The equivalent shear band viscosity computed by fitting the model to experimental displacement profiles is very close in value to typical liquid metal viscosities. The observation of similar displacement profiles across different metals shows that specific microstructure details do not affect the second phase. This also suggests that the principal role of the initiation phase is to generate a weak interface that is susceptible to localized deformation. Importantly, by constraining the sliding phase, we demonstrate a material-agnostic method-passive geometric flow control-that effects complete band suppression in systems which otherwise fail via shear banding.

Description of Self-efficacy and Initial Cognitive Abilities on the Students’ Physics Learning of the Direct Current Electrical Circuits

NASA Astrophysics Data System (ADS)

Zaenudin; Maknun, J.; Muslim

2017-03-01

This study aims to determine description of self -efficacy and initial cognitive abilities on the students of MAN 1 Bandung (senior high school) in learning physics on the subject of electrical circuits Direct Current (DC) before they get academy ask assigned in the classroom. From the results of this research can be used as a reference to provide appropriate measures for the advancement of student learning. The theory used in this research is the theory of Bandura. The design in this study using case study and data collection is done by tests and questionnaires, sampling techniques used by random sampling, the study was conducted on 10th grade students of MAN 1 Bandung by the amount of students 35 participants. The results of data analysis showed that the percentage of students who have moderate self-efficacy amounted to 67.05 %, and cognitive ability 50 %, this shows that the process of learning that takes place in school before that junior high school is not much scientific implement processes that provide students the opportunity to discover new things, then learning approaches of right is Problem Based Learning (PBL).

Direct simulation of high-speed mixing layers

NASA Technical Reports Server (NTRS)

Mukunda, H. S.; Sekar, B.; Carpenter, M. H.; Drummond, J. Philip; Kumar, Ajay

1992-01-01

A computational study of a nonreacting high-speed mixing layer is performed. A higher order algorithm with sufficient grid points is used to resolve all relevant scales. In all cases, a temporal free-stream disturbance is introduced. The resulting flow is time-sampled to generate a statistical cross section of the flow properties. The studies are conducted at two convective Mach numbers, three free-stream turbulence intensities, three Reynolds numbers, and two types of initial profiles-hyperbolic tangent (tanh) and boundary layer. The boundary-layer profile leads to more realistic predictions of the transition processes. The predicted transition Reynolds number of 0.18 x 10(exp 6) compares well with experimental data. Normalized vortex spacings for the boundary-layer case are about 3.5 and compare favorably with the 1.5 to 2.5 found in experimental measurements. The tanh profile produces spacings of about 10. The growth rate of the layer is shown to be moderately affected by the initial disturbance field, but comparison with experimental data shows moderate agreement. For the boundary-layer case, it is shown that noise at the Strouhal number of 0.007 is selectively amplified and shows little Reynolds number dependence.

Removal of cadmium ions from wastewater using innovative electronic waste-derived material.

PubMed

Xu, Meng; Hadi, Pejman; Chen, Guohua; McKay, Gordon

2014-05-30

Cadmium is a highly toxic heavy metal even at a trace level. In this study, a novel material derived from waste PCBs has been applied as an adsorbent to remove cadmium ions from aqueous solutions. The effects of various factors including contact time, initial cadmium ion concentration, pH and adsorbent dosage have been evaluated. The maximum uptake capacity of the newly derived material for cadmium ions has reached 2.1mmol/g at an initial pH 4. This value shows that this material can effectively remove cadmium ions from effluent. The equilibrium isotherm has been analyzed using several isotherm equations and is best described by the Redlich-Peterson model. Furthermore, different commercial adsorbent resins have been studied for comparison purposes. The results further confirm that this activated material is highly competitive with its commercial counterparts. Copyright © 2014 Elsevier B.V. All rights reserved.

Improving College Enrollment of At-Risk Students at the School Level.

PubMed

Goodwin, Ryan N; Li, Wei; Broda, Michael; Johnson, Heather; Schneider, Barbara

2016-01-01

Many federal, state, and local education policy priorities are aimed at preparing high school students, especially those at risk, to be college- and career-ready when they graduate from high school. A number of programs across different institutional entities have been initiated to achieve these goals, encompassing individual partnerships with schools. Many of these programs include a variety of interventions, ranging from college and course counseling to college visits. Although there have been some evaluations of the larger federal programs, and some state and district programs, few have examined national observational data on the impact of these programmatic efforts on college enrollments. This study uses the HSLS:09 database to investigate the impact of specific treatments in at-risk schools on college enrollments. Results show that several of these programmatic initiatives have a positive effect on college enrollment; however the effects are small compared to some of those reported by other national studies.

High-velocity facial gunshot wounds: multidisciplinary care from prehospital to discharge

PubMed Central

Sinnott, J D; Morris, G; Medland, P J; Porter, K

2016-01-01

A case is presented in which a high velocity rifle (shotgun) was fired into the inferior part of a patient's face in an attempted suicide causing widespread trauma to the inferior and left side of the patient's face. He presented to his general practitioner where an ambulance was called. The patient is followed from prehospital care (air ambulance) to resuscitation in accident and emergency and through the first stages of reconstructive surgery. The article focuses on the multidisciplinary approach to the patient's prehospital care and initial resuscitation at a major trauma centre. CT reconstruction images of the patient's skull allow visualisation of the extent of bone damage at presentation. Medical photography allows visualisation of the extent of the initial damage and shows how reconstructive surgery was undertaken early and in progressive stages. A literature review was performed allowing discussion of the current evidence and best practice in the management of facial gunshot wounds. PMID:26823355

On the generation of magnetosheath lion roars

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

Lee, L.C.; Wu, C.S.; Price, C.P.

1987-03-01

A theoretical model is proposed to discuss the electron dynamics associated with the mirror waves and their effects on the generation of the observed lion roars in the magnetosheath. It is pointed out that the usual double-adiabatic theory of hydromagnetics is not applicable to the electrons in mirror waves. Although the electron magnetic moment is conserved, the energy of each electron in the mirror waves is expected to be constant (because of the high electron speed along the magnetic field). Assuming an initial electron temperature anisotropy, the authors can show that in the low field region the electron temperature andmore » thermal anisotropy are higher than the initial values, whereas in the high field region the electron temperature and anisotropy are lower. This point can lead to a theoretical explanation of the important features of the observed lion roars. The present discussion complements the existing theories in the literature.« less

Extreme sensitivity of graphene photoconductivity to environmental gases.

PubMed

Docherty, Callum J; Lin, Cheng-Te; Joyce, Hannah J; Nicholas, Robin J; Herz, Laura M; Li, Lain-Jong; Johnston, Michael B

2012-01-01

Graphene is a single layer of covalently bonded carbon atoms, which was discovered only 8 years ago and yet has already attracted intense research and commercial interest. Initial research focused on its remarkable electronic properties, such as the observation of massless Dirac fermions and the half-integer quantum Hall effect. Now graphene is finding application in touch-screen displays, as channels in high-frequency transistors and in graphene-based integrated circuits. The potential for using the unique properties of graphene in terahertz-frequency electronics is particularly exciting; however, initial experiments probing the terahertz-frequency response of graphene are only just emerging. Here we show that the photoconductivity of graphene at terahertz frequencies is dramatically altered by the adsorption of atmospheric gases, such as nitrogen and oxygen. Furthermore, we observe the signature of terahertz stimulated emission from gas-adsorbed graphene. Our findings highlight the importance of environmental conditions on the design and fabrication of high-speed, graphene-based devices.

Reaction-induced rheological weakening enables oceanic plate subduction.

PubMed

Hirauchi, Ken-Ichi; Fukushima, Kumi; Kido, Masanori; Muto, Jun; Okamoto, Atsushi

2016-08-26

Earth is the only terrestrial planet in our solar system where an oceanic plate subducts beneath an overriding plate. Although the initiation of plate subduction requires extremely weak boundaries between strong plates, the way in which oceanic mantle rheologically weakens remains unknown. Here we show that shear-enhanced hydration reactions contribute to the generation and maintenance of weak mantle shear zones at mid-lithospheric depths. High-pressure friction experiments on peridotite gouge reveal that in the presence of hydrothermal water, increasing strain and reactions lead to an order-of-magnitude reduction in strength. The rate of deformation is controlled by pressure-solution-accommodated frictional sliding on weak hydrous phyllosilicate (talc), providing a mechanism for the 'cutoff' of the high peak strength at the brittle-plastic transition. Our findings suggest that infiltration of seawater into transform faults with long lengths and low slip rates is an important controlling factor on the initiation of plate tectonics on terrestrial planets.

Digital Topographic Mapping in Urban Obstructed Environment Based on Multi-GNSS Network RTK Technology

NASA Astrophysics Data System (ADS)

Guo, Qiuying; Zhao, Tonglong; Zhang, Chao; Wu, Xuxiang

2017-10-01

Digital topographic mapping experiments were carried out based on network RTK technology using GPS/BEIDOU/GLONASS multi-constellation compatible GNSS receivers in urban obstructed environment. Operation scheme and technique flow were discussed. Experimental results show that the horizontal position and elevation of the points measured by RTK can reach 2cm and 3cm precision level respectively in open environment. RTK initialization time needs about 3-5s. While in obstructed environment, such as high building and tree shanding, the RTK initialization time needs about dozens of seconds or tens of seconds, and sometimes floating solutions or even differential solutions were obtained. The impact of dense and tall building on RTK measurement is more seriously. It is more likely to get RTK fixed solution in the south side of high building than the north side of the building.

Improving College Enrollment of At-Risk Students at the School Level

PubMed Central

Goodwin, Ryan N.; Li, Wei; Broda, Michael; Johnson, Heather; Schneider, Barbara

2016-01-01

Many federal, state, and local education policy priorities are aimed at preparing high school students, especially those at risk, to be college- and career-ready when they graduate from high school. A number of programs across different institutional entities have been initiated to achieve these goals, encompassing individual partnerships with schools. Many of these programs include a variety of interventions, ranging from college and course counseling to college visits. Although there have been some evaluations of the larger federal programs, and some state and district programs, few have examined national observational data on the impact of these programmatic efforts on college enrollments. This study uses the HSLS:09 database to investigate the impact of specific treatments in at-risk schools on college enrollments. Results show that several of these programmatic initiatives have a positive effect on college enrollment; however the effects are small compared to some of those reported by other national studies. PMID:28138217

Favouring butyrate production for a new generation biofuel by acidogenic glucose fermentation using cells immobilised on γ-alumina.

PubMed

Syngiridis, Kostas; Bekatorou, Argyro; Kandylis, Panagiotis; Larroche, Christian; Kanellaki, Maria; Koutinas, Athanasios A

2014-06-01

The effect of γ-alumina as a fermentation advancing tool and as carrier for culture immobilisation, regarding VFAs and ethanol production during acidogenic fermentation of glucose, was examined at various process conditions (sugar concentration, pH) and operation modes (continuous with and without effluent recirculation and batch). The results showed that at high initial pH (8.9) the continuous acidogenic fermentation of glucose led to high yields of VFAs and favoured the accumulation of butyric acid. The batch process on the other hand at pH 6.5, favoured the ethanol-type fermentation. The results indicate that in the frame of technology development for new generation biofuels, using γ-alumina as a process advancing tool at optimum process conditions (pH, initial glucose concentration and mode of operation), the produced VFAs profile and ethanol concentration may be manipulated. Copyright © 2014. Published by Elsevier Ltd.

Modeling Initial Stage of Ablation Material Pyrolysis: Graphitic Precursor Formation and Interfacial Effects

NASA Technical Reports Server (NTRS)

Desai, Tapan G.; Lawson, John W.; Keblinski, Pawel

2010-01-01

Reactive molecular dynamics simulations are used to study initial stage of pyrolysis of ablation materials and their composites with carbon nanotubes and carbon fibers. The products formed during pyrolysis are characterized and water is found as the primary product in all cases. The water formation mechanisms are analyzed and the value of the activation energy for water formation is estimated. A detailed study on graphitic precursor formation reveals the presence of two temperature zones. In the lower temperature zone (less than 2000 K) polymerization occurs resulting in formation of large, stable graphitic precursors, and in the high temperature zone (greater than 2000 K) polymer scission results in formation of short polymer chains/molecules. Simulations performed in the high temperature zone on the phenolic resin composites (with carbon nanotubes and carbon fibers) shows that the presence of interfaces had no substantial effect on the chain scission rate or the activation energy value for water formation.

How do Indonesian youth perceive cigarette advertising? A cross-sectional study among Indonesian high school students

PubMed Central

Prabandari, Yayi Suryo; Dewi, Arika

2016-01-01

Background Previous studies have reported an association between cigarette advertising and smoking behavior. Although this has been reported extensively in the West, it has been reported less in Southeast Asian countries that have not completely banned tobacco advertising promotion and sponsorship (TAPS). Indonesia is the only ASEAN country that has not ratified the Framework Convention on Tobacco Control, so TAPS regulation is limited. This study aimed to assess the association between youths’ perceptions of cigarette ads and smoking initiation. Design We conducted a cross-sectional survey among 2,115 high school students aged 13–18 years in Yogyakarta, Indonesia. A self-administered questionnaire was distributed to gauge the perception of cigarette ads and initiation to smoking. We calculated the odds ratio (OR) between the perception of cigarette ads and smoking initiation, adjusting for sociodemographic and psychosocial variables. The sociodemographic variables included in the final model were age and sex. Results The final multivariate model showed an association between perception of tobacco ads encouraging youths to smoke and smoking initiation (OR 2.70) and current smoking (OR 7.63). Attitude toward TAPS was associated with smoking initiation (OR 1.51) and current smoking (OR 3.32). Exposure to cigarette ads had an association with smoking initiation only (OR 1.27) and did not have an association with current smoking. Having friends and family who smoked was associated with smoking initiation and current smoking in the final multivariate model. Smoking initiation and current smoking were also related to the susceptibility to smoke. Conclusions This study revealed that cigarette ads were perceived as encouraging youths to smoke and that smoking status was consistently associated with perception of cigarette ads targeted at youths, attitude toward TAPS, and susceptibility as well as smoking friends and family. Regulations to ban TAPS, particularly cigarette ads for preventing youths from smoking, should be adopted rapidly in Indonesia, where tobacco control remains limited. PMID:27578600

Initial eye movements during face identification are optimal and similar across cultures

PubMed Central

Or, Charles C.-F.; Peterson, Matthew F.; Eckstein, Miguel P.

2015-01-01

Culture influences not only human high-level cognitive processes but also low-level perceptual operations. Some perceptual operations, such as initial eye movements to faces, are critical for extraction of information supporting evolutionarily important tasks such as face identification. The extent of cultural effects on these crucial perceptual processes is unknown. Here, we report that the first gaze location for face identification was similar across East Asian and Western Caucasian cultural groups: Both fixated a featureless point between the eyes and the nose, with smaller between-group than within-group differences and with a small horizontal difference across cultures (8% of the interocular distance). We also show that individuals of both cultural groups initially fixated at a slightly higher point on Asian faces than on Caucasian faces. The initial fixations were found to be both fundamental in acquiring the majority of information for face identification and optimal, as accuracy deteriorated when observers held their gaze away from their preferred fixations. An ideal observer that integrated facial information with the human visual system's varying spatial resolution across the visual field showed a similar information distribution across faces of both races and predicted initial human fixations. The model consistently replicated the small vertical difference between human fixations to Asian and Caucasian faces but did not predict the small horizontal leftward bias of Caucasian observers. Together, the results suggest that initial eye movements during face identification may be driven by brain mechanisms aimed at maximizing accuracy, and less influenced by culture. The findings increase our understanding of the interplay between the brain's aims to optimally accomplish basic perceptual functions and to respond to sociocultural influences. PMID:26382003

Initiation and Along-Axis Segmentation of Seaward-Dipping Volcanic Sequences Captured in Afar

NASA Astrophysics Data System (ADS)

Ebinger, C.; Wolfenden, E.; Yirgu, G.; Keir, D.

2003-12-01

The Afar triple junction zone provides a unique opportunity to examine the early development of magmatic margins, as respective limbs of the triple junction capture different stages of the breakup process. Initial rifting in the southernmost Red Sea occurred concurrent with, or soon after flood basaltic magmatism at ~31 Ma in the Ethiopia-Yemen plume province, whereas the northern part of the Main Ethiopian rift initiated after 12 Ma. Both rift systems initiated with the development of high-angle border fault systems bounding broad basins, but 8-10 My after rifting we see riftward migration of strain from the western border fault to narrow zones of increasingly more basaltic magmatism. These localised zones of faulting and volcanism (magmatic segments) show a segmentation independent of the border fault segmentation. The much older, more evolved magmatic segments in the southern Red Sea, where not onlapped by Pliocene-Recent sedimentary strata, dip steeply riftward and define a regional eastward flexure into transitional oceanic crust, as indicated by gravity models constrained by seismic refraction and receiver function data. The southern Red Sea magmatic segments have been abandoned in Pliocene-Recent triple junction reorganisations, whereas the process of seaward-dipping volcanic sequence emplacement is ongoing in the seismically and volcanically active Main Ethiopian rift. Field, remote sensing, gravity, and seismicity data from the Main Ethiopian and southern Red Sea rifts indicate that seaward-dipping volcanic sequences initiate in moderately stretched continental crust above a narrow zone of dike-intrusion. Our comparison of active and ancient magmatic segments show that they are the precursors to seaward-dipping volcanic sequences analogous to those seen on passive continental margins, and provides insights into the initiation of along-axis segmentation of seafloor-spreading centers.

Fast Positive Breakdown, NBEs, and Lightning Initiation

NASA Astrophysics Data System (ADS)

Krehbiel, P. R.; Rison, W.; Stock, M.; Edens, H. E.; Shao, X. M.; Thomas, R. J.; Stanley, M. A.; Zhang, Y.

2016-12-01

High power narrrow bipolar events (NBEs) have been found to be produced by arelatively unknown type of discharge, called fast positive breakdown (Rison etal., 2016). The breakdown occurs with a wide range of strengths, both in terms of its broadband sferic and its VHF radiation, and is found to be theinitiating event of many and likely all lightning discharges inside storms. Itdoes not produce a conducting channel but instead appears to be produced by avolumetric system of repeated, cascading positive streamers in virgin air.That positive corona and streamers would be responsible for initiatinglightning was proposed in the 1960s by Loeb, Dawson and Winn. In the 1970sPhelps and Griffiths showed that the streamers would be self-intensifying,leading to negative breakdown being initiated back at their starting points.Petersen et al. (2008) described experimental results showing that thestreamers could be initiated by ice crystals at cold temperatures, and thephysical processes leading to the breakdown being fast has been reported inrecent modeling studies by Shi et al. (2016). In this paper we summarize the observational data in support of the abovefindings, and report on additional observations of NBEs and lightninginitiation currently being obtained at Kennedy Space Center, Florida. References: Rison W., P.R. Krehbiel M.G.Stock, H.E. Edens, X-M. Shao, R.J. Thomas,M.A. Stanley, Y. Zhang, Observations of narrow bipolar events revealhow lightning is initiated in thunderstorms, Nature Comms. 7, 2016.doi:10.1038/ncomms10721. Petersen, D., Bailey, M., Beasley, W. & Hallett, J. A brief review ofthe problem of lightning initiation and a hypothesis of initiallightning leader formation. J. Geophys. Res. 113, D17205 (2008). Shi, F., N. Liu, and H. K. Rassoul (2016), Properties of relativelylong streamers initiated from an isolated hydrometeor, J. Geophys.Res. Atmos., 121, 7284-7295, doi:10.1002/2015JD024580.

Context predicts word order processing in Broca's region.

PubMed

Kristensen, Line Burholt; Engberg-Pedersen, Elisabeth; Wallentin, Mikkel

2014-12-01

The function of the left inferior frontal gyrus (L-IFG) is highly disputed. A number of language processing studies have linked the region to the processing of syntactical structure. Still, there is little agreement when it comes to defining why linguistic structures differ in their effects on the L-IFG. In a number of languages, the processing of object-initial sentences affects the L-IFG more than the processing of subject-initial ones, but frequency and distribution differences may act as confounding variables. Syntactically complex structures (like the object-initial construction in Danish) are often less frequent and only viable in certain contexts. With this confound in mind, the L-IFG activation may be sensitive to other variables than a syntax manipulation on its own. The present fMRI study investigates the effect of a pragmatically appropriate context on the processing of subject-initial and object-initial clauses with the IFG as our ROI. We find that Danish object-initial clauses yield a higher BOLD response in L-IFG, but we also find an interaction between appropriateness of context and word order. This interaction overlaps with traditional syntax areas in the IFG. For object-initial clauses, the effect of an appropriate context is bigger than for subject-initial clauses. This result is supported by an acceptability study that shows that, given appropriate contexts, object-initial clauses are considered more appropriate than subject-initial clauses. The increased L-IFG activation for processing object-initial clauses without a supportive context may be interpreted as reflecting either reinterpretation or the recipients' failure to correctly predict word order from contextual cues.

Convective and microphysics parameterization impact on simulating heavy rainfall in Semarang (case study on February 12th, 2015)

NASA Astrophysics Data System (ADS)

Faridatussafura, Nurzaka; Wandala, Agie

2018-05-01

The meteorological model WRF-ARW version 3.8.1 is used for simulating the heavy rainfall in Semarang that occurred on February 12th, 2015. Two different convective schemes and two different microphysics scheme in a nested configuration were chosen. The sensitivity of those schemes in capturing the extreme weather event has been tested. GFS data were used for the initial and boundary condition. Verification on the twenty-four hours accumulated rainfall using GSMaPsatellite data shows that Kain-Fritsch convective scheme and Lin microphysics scheme is the best combination scheme among the others. The combination also gives the highest success ratio value in placing high intensity rainfall area. Based on the ROC diagram, KF-Lin shows the best performance in detecting high intensity rainfall. However, the combination still has high bias value.

Dimer esters in α-pinene secondary organic aerosol: effect of hydroxyl radical, ozone, relative humidity and aerosol acidity

NASA Astrophysics Data System (ADS)

Kristensen, K.; Cui, T.; Zhang, H.; Gold, A.; Glasius, M.; Surratt, J. D.

2013-12-01

The formation of secondary organic aerosol (SOA) from both ozonolysis and hydroxyl radical (OH)-initiated oxidation of α-pinene under conditions of high nitric oxide (NO) concentrations with varying relative humidity (RH) and aerosol acidity was investigated in the University of North Carolina dual outdoor smog chamber facility. SOA formation from ozonolysis of α-pinene was enhanced relative to that from OH-initiated oxidation in the presence of initially high NO conditions. However, no effect of RH on SOA mass was evident. Ozone (O3)-initiated oxidation of α-pinene in the presence of ammonium sulfate (AS) seed coated with organic aerosol from OH-initiated oxidation of α-pinene showed reduced nucleation compared to ozonolysis in the presence of pure AS seed aerosol. The chemical composition of α-pinene SOA was investigated by ultra-performance liquid chromatography/electrospray ionization high-resolution quadrupole time-of-flight mass spectrometry (UPLC/ESI-HR-Q-TOFMS), with a focus on the formation of carboxylic acids and high-molecular weight dimer esters. A total of eight carboxylic acids and four dimer esters were identified, constituting between 8 and 12% of the total α-pinene SOA mass. OH-initiated oxidation of α-pinene in the presence of nitrogen oxides (NOx) resulted in the formation of highly oxidized carboxylic acids, such as 3-methyl-1,2,3-butanetricarboxylic acid (MBTCA) and diaterpenylic acid acetate (DTAA). The formation of dimer esters was observed only in SOA produced from the ozonolysis of α-pinene in the absence of NOx, with increased concentrations by a~factor of two at higher RH (50-90%) relative to lower RH (30-50%). The increased formation of dimer esters correlates with an observed increase in new particle formation at higher RH due to nucleation. Increased aerosol acidity was found to have a negligible effect on the formation of the dimer esters. SOA mass yield did not influence the chemical composition of SOA formed from α-pinene ozonolysis with respect to carboxylic acids and dimer esters. The results support the formation of the high-molecular weight dimer esters through gas-phase reactions of the stabilized Criegee Intermediate (sCI) formed from the ozonolysis of α-pinene. The high molecular weight and polar nature of dimer esters formed in the gas-phase may explain increased particle number concentration as a~result of homogenous nucleation. Since three of these dimer esters (i.e., pinyl-diaterpenyl ester (MW 358), pinyl-diaterebyl ester (MW 344) and pinonyl-pinyl ester (MW 368)) have been observed in both laboratory-generated and ambient fine organic aerosol samples, we conclude that the dimer esters observed in this study can be used as tracers for the O3-initiated oxidation of α-pinene, and are therefore indicative of enhanced anthropogenic activities, and that the high molecular weight and low volatility esters result in homogenous nucleation under laboratory conditions, increasing the particle number concentration.

Dimers in α-pinene secondary organic aerosol: effect of hydroxyl radical, ozone, relative humidity and aerosol acidity

NASA Astrophysics Data System (ADS)

Kristensen, K.; Cui, T.; Zhang, H.; Gold, A.; Glasius, M.; Surratt, J. D.

2014-04-01

The formation of secondary organic aerosol (SOA) from both ozonolysis and hydroxyl radical (OH)-initiated oxidation of α-pinene under conditions of high nitric oxide (NO) concentrations with varying relative humidity (RH) and aerosol acidity was investigated in the University of North Carolina dual outdoor smog chamber facility. SOA formation from ozonolysis of α-pinene was enhanced relative to that from OH-initiated oxidation in the presence of initially high-NO conditions. However, no effect of RH on SOA mass was evident. Ozone (O3)-initiated oxidation of α-pinene in the presence of ammonium sulfate (AS) seed coated with organic aerosol from OH-initiated oxidation of α-pinene showed reduced nucleation compared to ozonolysis in the presence of pure AS seed aerosol. The chemical composition of α-pinene SOA was investigated by ultra-performance liquid chromatography/electrospray ionization high-resolution quadrupole time-of-flight mass spectrometry (UPLC/ESI-HR-Q-TOFMS), with a focus on the formation of carboxylic acids and high-molecular weight dimers. A total of eight carboxylic acids and four dimers were identified, constituting between 8 and 12% of the total α-pinene SOA mass. OH-initiated oxidation of α-pinene in the presence of nitrogen oxides (NOx) resulted in the formation of highly oxidized carboxylic acids, such as 3-methyl-1,2,3-butanetricarboxylic acid (MBTCA) and diaterpenylic acid acetate (DTAA). The formation of dimers was observed only in SOA produced from the ozonolysis of α-pinene in the absence of NOx, with increased concentrations by a factor of two at higher RH (50-90%) relative to lower RH (30-50%). The increased formation of dimers correlates with an observed increase in new particle formation at higher RH due to nucleation. Increased aerosol acidity was found to have a negligible effect on the formation of the dimers. SOA mass yield did not influence the chemical composition of SOA formed from α-pinene ozonolysis with respect to carboxylic acids and dimers. The results support the formation of the high-molecular weight dimers through gas-phase reactions of the stabilized Criegee Intermediate (sCI) formed from the ozonolysis of α-pinene. The high molecular weight and polar nature of dimers formed in the gas phase may explain increased particle number concentration as a result of homogenous nucleation. Since three of these dimers (i.e. pinyl-diaterpenyl dimer (MW 358), pinyl-diaterebyl dimer (MW 344) and pinonyl-pinyl dimer (MW 368)) have been observed in both laboratory-generated and ambient fine organic aerosol samples, we conclude that the dimers observed in this study can be used as tracers for the O3-initiated oxidation of α-pinene, and are therefore indicative of enhanced anthropogenic activities, and that the high molecular weight and low volatility dimers result in homogenous nucleation under laboratory conditions, increasing the particle number concentration.

Short-Term Effects of Thoracic Spine Manipulation on the Biomechanical Organisation of Gait Initiation: A Randomized Pilot Study

PubMed Central

Ditcharles, Sébastien; Yiou, Eric; Delafontaine, Arnaud; Hamaoui, Alain

2017-01-01

Speed performance during gait initiation is known to be dependent on the capacity of the central nervous system to generate efficient anticipatory postural adjustments (APA). According to the posturo-kinetic capacity (PKC) concept, any factor enhancing postural chain mobility and especially spine mobility, may facilitate the development of APA and thus speed performance. “Spinal Manipulative Therapy High-Velocity, Low-Amplitude” (SMT-HVLA) is a healing technique applied to the spine which is routinely used by healthcare practitioners to improve spine mobility. As such, it may have a positive effect on the PKC and therefore facilitate gait initiation. The present study aimed to investigate the short-term effect of thoracic SMT-HVLA on spine mobility, APA and speed performance during gait initiation. Healthy young adults (n = 22) performed a series of gait initiation trials on a force plate before (“pre-manipulation” condition) and after (“post-manipulation” condition) a sham manipulation or an HVLA manipulation applied to the ninth thoracic vertebrae (T9). Participants were randomly assigned to the sham (n = 11) or the HVLA group (n = 11).The spine range of motion (ROM) was assessed in each participant immediately after the sham or HVLA manipulations using inclinometers. The results showed that the maximal thoracic flexion increased in the HVLA group after the manipulation, which was not the case in the sham group. In the HVLA group, results further showed that each of the following gait initiation variables reached a significantly lower mean value in the post-manipulation condition as compared to the pre-manipulation condition: APA duration, peak of anticipatory backward center of pressure displacement, center of gravity velocity at foot-off, mechanical efficiency of APA, peak of center of gravity velocity and step length. In contrast, for the sham group, results showed that none of the gait initiation variables significantly differed between the pre- and post-manipulation conditions. It is concluded that HVLA manipulation applied to T9 has an immediate beneficial effect on spine mobility but a detrimental effect on APA development and speed performance during gait initiation. We suggest that a neural effect induced by SMT-HVLA, possibly mediated by a transient alteration in the early sensory-motor integration, might have masked the potential mechanical benefits associated with increased spine mobility. PMID:28713254

In vivo urethral dose measurements: a method to verify high dose rate prostate treatments.

PubMed

Brezovich, I A; Duan, J; Pareek, P N; Fiveash, J; Ezekiel, M

2000-10-01

Radiation doses delivered in high dose rate (HDR) brachytherapy are susceptible to many inaccuracies and errors, including imaging, planning and delivery. Consequently, the dose delivered to the patient may deviate substantially from the treatment plan. We investigated the feasibility of using TLD measurements in the urethra to estimate the discrepancy in treatments for prostate cancer. The dose response of the 1 mm diam, 6 mm long LiF rods that we used for the in vivo measurements was calibrated with the 192Ir HDR source, as well as a 60Co teletherapy unit. A train of 20 rods contained in a sterile plastic tube was inserted into the urethral (Foley) catheter for the duration of a treatment fraction, and the measured doses were compared to the treatment plan. Initial results from a total of seven treatments in four patients show good agreement between theory and experiment. Analysis of any one treatment showed agreement within 11.7% +/- 6.2% for the highest dose encountered in the central prostatic urethra, and within 10.4% +/- 4.4% for the mean dose. Taking the average over all seven treatments shows agreement within 1.7% for the maximum urethral dose, and within 1.5% for the mean urethral dose. Based on these initial findings it seems that planned prostate doses can be accurately reproduced in the clinic.

Reduction of the pace polarization artefact for capture detection applications by a tri-phasic stimulation pulse.

PubMed

Sutton, R; Fröhlig, G; de Voogt, W G; Goethals, M; Hintringer, F; Kennergren, C; Scanu, P; Guilleman, D; Treese, N; Hartung, W M; Stammwitz, E; Muetstege, A

2004-11-01

This study investigated the ability to minimize pace polarization artefacts (PPA) by adjusting the post-stimulus pulse duration of a tri-phasic stimulation pulse. Adjustment of the stimulation pulse was enabled by downloading special study software into an already implanted pacemaker. Tests were performed in a total of 296 atrial leads and 311 ventricular leads. Both chronic and acute leads were included in the study. Statistically significant differences were found in the initial PPA (without any adjustment of the stimulus pulse) between atrial and ventricular leads. In addition, significant differences were observed among various lead models with respect to changes over time in the initial ventricular PPA. Successful PPA reduction was defined as a reduction of the PPA below 0.5 mV for atrial leads and below 1 mV for ventricular leads. Results show a success rate for ventricular and atrial PPA reduction of 97.8% and 98.7%, respectively. Threshold tests showed that after reduction of the PPA loss of ventricular capture can be reliably detected. However, atrial threshold tests showed many false positive evoked response detections. In addition, unexpectedly high evoked response amplitudes were observed in the atrium after reduction of the PPA. Results from additional measurements suggest that these high atrial evoked response amplitudes come from the influence of the input filter of the pacemaker.

Expression patterns of TEL genes in Poaceae suggest a conserved association with cell differentiation.

PubMed

Paquet, Nicolas; Bernadet, Marie; Morin, Halima; Traas, Jan; Dron, Michel; Charon, Celine

2005-06-01

Poaceae species present a conserved distichous phyllotaxy (leaf position along the stem) and share common properties with respect to leaf initiation. The goal of this work was to determine if these common traits imply common genes. Therefore, homologues of the maize TERMINAL EAR1 gene in Poaceae were studied. This gene encodes an RNA-binding motif (RRM) protein, that is suggested to regulate leaf initiation. Using degenerate primers, one unique tel (terminal ear1-like) gene from seven Poaceae members, covering almost all the phylogenetic tree of the family, was identified by PCR. These genes present a very high degree of similarity, a much conserved exon-intron structure, and the three RRMs and TEL characteristic motifs. The evolution of tel sequences in Poaceae strongly correlates with the known phylogenetic tree of this family. RT-PCR gene expression analyses show conserved tel expression in the shoot apex in all species, suggesting functional orthology between these genes. In addition, in situ hybridization experiments with specific antisense probes show tel transcript accumulation in all differentiating cells of the leaf, from the recruitment of leaf founder cells to leaf margins cells. Tel expression is not restricted to initiating leaves as it is also found in pro-vascular tissues, root meristems, and immature inflorescences. Therefore, these results suggest that TEL is not only associated with leaf initiation but more generally with cell differentiation in Poaceae.

The role of prevention focus under stereotype threat: Initial cognitive mobilization is followed by depletion.

PubMed

Ståhl, Tomas; Van Laar, Colette; Ellemers, Naomi

2012-06-01

Previous research has demonstrated that stereotype threat induces a prevention focus and impairs central executive functions. The present research examines how these 2 consequences of stereotype threat are related. The authors argue that the prevention focus is responsible for the effects of stereotype threat on executive functions and cognitive performance. However, because the prevention focus is adapted to deal with threatening situations, the authors propose that it also leads to some beneficial responses to stereotype threat. Specifically, because stereotype threat signals a high risk of failure, a prevention focus initiates immediate recruitment of cognitive control resources. The authors further argue that this response initially facilitates cognitive performance but that the additional cognitive demands associated with working under threat lead to cognitive depletion over time. Study 1 demonstrates that stereotype threat (vs. control) facilitates immediate cognitive control capacity during a stereotype-relevant task. Study 2 experimentally demonstrates the process by showing that stereotype threat (vs. control) facilitates cognitive control as a default, as well as when a prevention focus has been experimentally induced, but not when a promotion focus has been induced. Study 3 shows that stereotype threat facilitates initial math performance under a prevention focus, whereas no effect is found under a promotion focus. Consistent with previous research, however, stereotype threat impaired math performance over time under a prevention focus, but not under a promotion focus. 2012 APA, all rights reserved

An Experimental study of Corner Turning in a Granular Ammonium Nitrate Based Explosive

NASA Astrophysics Data System (ADS)

Sorber, Susan; Taylor, Peter

2007-06-01

A novel experimental geometry has been designed to perform controlled studies of corner turning in a ``tap density'' granular explosive. It enables the study of corner turning and detonation properties with high speed framing camera, piezo probes and ionization probes. The basic geometry consists of a large diameter PMMA cylinder filled with the granular explosive which is initiated on axis from below by a smaller diameter cylinder of the same explosive or a booster charge. Four experiments have been performed on a granular Ammonium Nitrate based non ideal explosive (NIE). Two experiments were initiated directly from a PE4 booster charge and two were initiated from a train including a booster charge and a 1'' diameter Copper cylinder containing the same NIE. Data from the four experiments was reproducible and observed detonation and shock waves showed good 2-D symmetry. Detonation phase velocity on the vertical side of the main container was observed and both shock and detonation velocities were observed in the corner turning region along the base of the main container. Analysis of the data shows that the booster initiated geometries with a higher input shock pressure into the NIE gave earlier detonation arrival at the lowest probes on the container side. The corner turning data is compared to a hydrocode calculation using a simple JWL++ reactive burn model.

An Experimental Study of Corner Turning in a Granular Ammonium Nitrate Based Explosive

NASA Astrophysics Data System (ADS)

Sorber, S.; Taylor, P.; Burns, M.

2007-12-01

A novel experimental geometry has been designed to perform controlled studies of corner turning in a "tap density" granular explosive. It enables the study of corner turning and detonation properties with high speed framing camera, piezo probes and ionisation probes. The basic geometry consists of a large diameter PMMA cylinder filled with the granular explosive and is initiated on axis from below by a smaller diameter cylinder of granular explosive or a booster charge. Four experiments were performed on a granular Ammonium Nitrate based non-ideal explosive (NIE). Two experiments were initiated directly with the PE4 booster and two were initiated from a train including a booster charge and a 1″ diameter copper cylinder containing the same NIE. Experimental data from the four experiments was reproducible and the observed detonation and shock waves showed good 2-D symmetry. Detonation phase velocity on the vertical side of the main container was observed and both shock and detonation velocities were observed in the corner turning region along the base of the main container. Analysis of the data shows that the booster-initiated geometries with a higher input shock pressure into the granular explosive gave earlier detonation arrival at the lowest probes on the container side. The corner turning data is compared to a hydrocode calculation using a simple JWL++ reactive burn model.

Recruitment of Mcm10 to Sites of Replication Initiation Requires Direct Binding to the Minichromosome Maintenance (MCM) Complex*

PubMed Central

Douglas, Max E.

2016-01-01

Mcm10 is required for the initiation of eukaryotic DNA replication and contributes in some unknown way to the activation of the Cdc45-MCM-GINS (CMG) helicase. How Mcm10 is localized to sites of replication initiation is unclear, as current models indicate that direct binding to minichromosome maintenance (MCM) plays a role, but the details and functional importance of this interaction have not been determined. Here, we show that purified Mcm10 can bind both DNA-bound double hexamers and soluble single hexamers of MCM. The binding of Mcm10 to MCM requires the Mcm10 C terminus. Moreover, the binding site for Mcm10 on MCM includes the Mcm2 and Mcm6 subunits and overlaps that for the loading factor Cdt1. Whether Mcm10 recruitment to replication origins depends on CMG helicase assembly has been unclear. We show that Mcm10 recruitment occurs via two modes: low affinity recruitment in the absence of CMG assembly (“G1-like”) and high affinity recruitment when CMG assembly takes place (“S-phase-like”). Mcm10 that cannot bind directly to MCM is defective in both modes of recruitment and is unable to support DNA replication. These findings indicate that Mcm10 is localized to replication initiation sites by directly binding MCM through the Mcm10 C terminus. PMID:26719337

Qubit-qubit entanglement dynamics control via external classical pumping and Kerr nonlinearity mediated by a single detuned cavity field powered by two-photon processes

NASA Astrophysics Data System (ADS)

Ateto, M. S.

2017-11-01

The nonlinear time-dependent two-photon Hamiltonian of a couple of classically pumped independent qubits is analytically solved, and the corresponding time evolution unitary operator, in an exact form, is derived. Using the concurrence, entanglement dynamics between the qubits under the influence of a wide range of effective parameters are examined and, in detail, analyzed. Observations analysis is documented with aid of the field phase-space distribution Wigner function. A couple of initial qubit states is considered, namely similar excited states and a Bell-like pure state. It is demonstrated that an initial Bell-like pure state is as well typical initial qubits setting for robust, regular and a high degree of entanglement. Moreover, it is established that high-constant Kerr media represent an effective tool for generating periodical entanglement at fixed time cycles of maxima reach unity forever when qubits are initially in a Bell-like pure state. Further, it is showed that the medium strength of the classical pumping stimulates efficiently qubits entanglement, specially, when the interaction occurs off resonantly. However, the high-intensity pumping thermalizes the coherent distribution of photons, thus, the least photons number is used and, hence, the least minimum degree of qubits entanglement could be created. Furthermore, when the cavity field and external pumping are detuned, the external pumping acts like an auxiliary effective frequency for the cavity, as a result, the field Gaussian distribution acquires linear chirps, and consequently, more entanglement revivals appear in the same cycle during timescale.

The Protective Influence of Family Bonding on Smoking Initiation in Adolescents by Racial/Ethnic and Age Subgroups

PubMed Central

Mahabee-Gittens, E. Melinda; Khoury, Jane C.; Huang, Bin; Dorn, Lorah D.; Ammerman, Robert T.; Gordon, Judith S.

2011-01-01

Using data from the National Longitudinal Study of Adolescent Health, this study examined the associations among family bonding factors and the initiation of smoking by race/ethnicity and age group among nonsmokers at Wave 1. Overall, 18% of the sample initiated smoking by Wave 2. For younger African American and Hispanic youth, high maternal satisfaction with the relationship was significantly protective of smoking initiation. For older Hispanics, high parental presence and high parent-family connectedness were protective against smoking initiation while lack of awareness about the adolescent’s whereabouts was a risk factor for initiation in both younger and older Caucasians, and in the older Hispanics. Our results underscore the importance of maintaining high levels of family bonding with the adolescent throughout early and late adolescence in order to decrease tobacco initiation. PMID:22267899

UV-induced photocatalytic degradation of aqueous acetaminophen: the role of adsorption and reaction kinetics.

PubMed

Basha, Shaik; Keane, David; Nolan, Kieran; Oelgemöller, Michael; Lawler, Jenny; Tobin, John M; Morrissey, Anne

2015-02-01

Nanostructured titania supported on activated carbon (AC), termed as integrated photocatalytic adsorbents (IPCAs), were prepared by ultrasonication and investigated for the photocatalytic degradation of acetaminophen (AMP), a common analgesic and antipyretic drug. The IPCAs showed high affinity towards AMP (in dark adsorption studies), with the amount adsorbed proportional to the TiO2 content; the highest adsorption was at 10 wt% TiO2. Equilibrium isotherm studies showed that the adsorption followed the Langmuir model, indicating the dependence of the reaction on an initial adsorption step, with maximum adsorption capacity of 28.4 mg/g for 10 % TiO2 IPCA. The effects of initial pH, catalyst amount and initial AMP concentration on the photocatalytic degradation rates were studied. Generally, the AMP photodegradation activity of the IPCAs was better than that of bare TiO2. Kinetic studies on the photocatalytic degradation of AMP under UV suggest that the degradation followed Langmuir-Hinshelwood (L-H) kinetics, with an adsorption rate constant (K) that was considerably higher than the photocatalytic rate constant (k r), indicating that the photocatalysis of AMP is the rate-determining step during the adsorption/photocatalysis process.

IMPACT Is a Developmentally Regulated Protein in Neurons That Opposes the Eukaryotic Initiation Factor 2α Kinase GCN2 in the modulation of Neurite Outgrowth*

PubMed Central

Roffé, Martín; Hajj, Glaucia N. M.; Azevedo, Hátylas F.; Alves, Viviane S.; Castilho, Beatriz A.

2013-01-01

The product of the mouse Imprinted and Ancient gene, IMPACT, is preferentially expressed in neurons. We have previously shown that IMPACT overexpression inhibits the activation of the protein kinase GCN2, which signals amino acid starvation. GCN2 phosphorylates the α-subunit of eukaryotic translation initiation factor 2 (eIF2α), resulting in inhibition of general protein synthesis but increased translation of specific messages, such as ATF4. GCN2 is also involved in the regulation of neuronal functions, controlling synaptic plasticity, memory, and feeding behavior. We show here that IMPACT abundance increases during differentiation of neurons and neuron-like N2a cells, whereas GCN2 displays lowered activation levels. Upon differentiation, IMPACT associates with translating ribosomes, enhances translation initiation, and down-regulates the expression of ATF4. We further show that endogenous IMPACT promotes neurite outgrowth whereas GCN2 is a strong inhibitor of spontaneous neuritogenesis. Together, these results uncover the participation of the GCN2-IMPACT module of translational regulation in a highly controlled step in the development of the nervous system. PMID:23447528

IMPACT is a developmentally regulated protein in neurons that opposes the eukaryotic initiation factor 2α kinase GCN2 in the modulation of neurite outgrowth.

PubMed

Roffé, Martín; Hajj, Glaucia N M; Azevedo, Hátylas F; Alves, Viviane S; Castilho, Beatriz A

2013-04-12

The product of the mouse Imprinted and Ancient gene, IMPACT, is preferentially expressed in neurons. We have previously shown that IMPACT overexpression inhibits the activation of the protein kinase GCN2, which signals amino acid starvation. GCN2 phosphorylates the α-subunit of eukaryotic translation initiation factor 2 (eIF2α), resulting in inhibition of general protein synthesis but increased translation of specific messages, such as ATF4. GCN2 is also involved in the regulation of neuronal functions, controlling synaptic plasticity, memory, and feeding behavior. We show here that IMPACT abundance increases during differentiation of neurons and neuron-like N2a cells, whereas GCN2 displays lowered activation levels. Upon differentiation, IMPACT associates with translating ribosomes, enhances translation initiation, and down-regulates the expression of ATF4. We further show that endogenous IMPACT promotes neurite outgrowth whereas GCN2 is a strong inhibitor of spontaneous neuritogenesis. Together, these results uncover the participation of the GCN2-IMPACT module of translational regulation in a highly controlled step in the development of the nervous system.

Extreme multistability analysis of memristor-based chaotic system and its application in image decryption

NASA Astrophysics Data System (ADS)

Li, Chuang; Min, Fuhong; Jin, Qiusen; Ma, Hanyuan

2017-12-01

An active charge-controlled memristive Chua's circuit is implemented, and its basic properties are analyzed. Firstly, with the system trajectory starting from an equilibrium point, the dynamic behavior of multiple coexisting attractors depending on the memristor initial value and the system parameter is studied, which shows the coexisting behaviors of point, period, chaos, and quasic-period. Secondly, with the system motion starting from a non-equilibrium point, the dynamics of extreme multistability in a wide initial value domain are easily conformed by new analytical methods. Furthermore, the simulation results indicate that some strange chaotic attractors like multi-wing type and multi-scroll type are observed when the observed signals are extended from voltage and current to power and energy, respectively. Specially, when different initial conditions are taken, the coexisting strange chaotic attractors between the power and energy signals are exhibited. Finally, the chaotic sequences of the new system are used for encrypting color image to protect image information security. The encryption performance is analyzed by statistic histogram, correlation, key spaces and key sensitivity. Simulation results show that the new memristive chaotic system has high security in color image encryption.

Atmospheric response to anomalous autumn surface forcing in the Arctic Basin

NASA Astrophysics Data System (ADS)

Cassano, Elizabeth N.; Cassano, John J.

2017-09-01

Data from four reanalyses are analyzed to evaluate the downstream atmospheric response both spatially and temporally to anomalous autumn surface forcing in the Arctic Basin. Running weekly mean skin temperature anomalies were classified using the self-organizing map algorithm. The resulting classes were used to both composite the initial atmospheric state and determine how the atmosphere evolves from this state. The strongest response was to anomalous forcing—positive skin temperature and total surface energy flux anomalies and reduced sea ice concentration—in the Barents and Kara Seas. Analysis of the evolution of the atmospheric state for 12 weeks after the initial forcing showed a persistence in the anomalies in this area which led to a buildup of heat in the atmosphere. This resulted in positive 1000-500 hPa thickness and high-pressure circulation anomalies in this area which were associated with cold air advection and temperatures over much of central and northern Asia. Evaluation of days with the opposite forcing (i.e., negative skin temperature anomalies and increased sea ice concentration in the Barents and Kara Seas) showed a mirrored, opposite downstream atmospheric response. Other patterns with positive skin temperature anomalies in the Arctic Basin did not show the same response most likely because the anomalies were not as strong nor did they persist for as many weeks following the initial forcing.

Interventions to increase initial appointment attendance in mental health services: a systematic review.

PubMed

Schauman, Oliver; Aschan, Lisa Ellinor; Arias, Nicole; Beards, Stephanie; Clement, Sarah

2013-12-01

OBJECTIVE Although nonattendance at initial appointments in mental health services is a substantial problem, the phenomenon is poorly understood. This review synthesized findings of randomized controlled trials (RCTs) of interventions to increase initial appointment attendance and determined whether theories or models contributed to intervention design. METHODS Six electronic databases were systematically searched, and reference lists of identified studies were also examined. Studies included were RCTs (including "quasi-randomized" controlled trials) that compared standard practice with an intervention to increase attendance at initial appointments in a sample of adults who had a scheduled initial appointment in a mental health or substance abuse service setting. RESULTS Of 144 potentially relevant studies, 21 met inclusion criteria. These studies were reported in 20 different research papers. Of these, 16 studies (N=3,673 participants) were included in the analyses (five were excluded because they reported only nonattendance at the initial appointment). Separate analyses were conducted for each intervention type (opt-in systems, telephone reminders and prompts, orientation and reminder letters, accelerated intake, preappointment completion of psychodynamic questionnaires, and "other"). Narrative synthesis was used for analysis because the high level of heterogeneity between studies precluded a meta-analysis. The results were mixed for all types of intervention. Some isolated high-quality studies of opt-in systems, orientation and reminder letters, and more novel interventions demonstrated a beneficial effect. CONCLUSIONS The synthesized findings indicated that orientation and reminder letters may have a small beneficial effect. Consistent evidence for the efficacy of other types of common interventions is lacking. More novel interventions, such as asking clients to formulate plans to deal with obstacles to attendance and giving clients a choice of therapist style, showed some promise, but studies require replication.

Liquid-metal-fed Pulsed Plasma Thrusters for In-space Propulsion

NASA Technical Reports Server (NTRS)

Markusic, Thomas E.

2004-01-01

Liquid metal propellants may provide a path toward more reliable and efficient pulsed plasma thrusters (PPTs). Conceptual thruster designs which eliminate the need for high current switches and propellant metering valves are described. Propellant loading techniques are suggested that show promise to increase thruster propellant utilization, dynamic, and electrical efficiency. Calibration results from a compact, electromagnetically-pumped propellant feed system are presented. Results for lithium and gallium propellants show capability to meter propellant at flow rates up to 10 +/- 0.1 mg/s. Experiments investigating the initiation of arc discharges using liquid metal droplets are presented. High speed photography and laser interferometry provide spatially and temporally resolved information on the decomposition of liquid metal droplets , and the evolution of the accelerating current channel.

Discovery of a novel general anesthetic chemotype using high-throughput screening.

PubMed

McKinstry-Wu, Andrew R; Bu, Weiming; Rai, Ganesha; Lea, Wendy A; Weiser, Brian P; Liang, David F; Simeonov, Anton; Jadhav, Ajit; Maloney, David J; Eckenhoff, Roderic G

2015-02-01

The development of novel anesthetics has historically been a process of combined serendipity and empiricism, with most recent new anesthetics developed via modification of existing anesthetic structures. Using a novel high-throughput screen employing the fluorescent anesthetic 1-aminoanthracene and apoferritin as a surrogate for on-pathway anesthetic protein target(s), we screened a 350,000 compound library for competition with 1-aminoanthracene-apoferritin binding. Hit compounds meeting structural criteria had their binding affinities for apoferritin quantified with isothermal titration calorimetry and were tested for γ-aminobutyric acid type A receptor binding using a flunitrazepam binding assay. Chemotypes with a strong presence in the top 700 and exhibiting activity via isothermal titration calorimetry were selected for medicinal chemistry optimization including testing for anesthetic potency and toxicity in an in vivo Xenopus laevis tadpole assay. Compounds with low toxicity and high potency were tested for anesthetic potency in mice. From an initial chemical library of more than 350,000 compounds, we identified 2,600 compounds that potently inhibited 1-aminoanthracene binding to apoferritin. A subset of compounds chosen by structural criteria (700) was successfully reconfirmed using the initial assay. Based on a strong presence in both the initial and secondary screens the 6-phenylpyridazin-3(2H)-one chemotype was assessed for anesthetic activity in tadpoles. Medicinal chemistry efforts identified four compounds with high potency and low toxicity in tadpoles, two were found to be effective novel anesthetics in mice. The authors demonstrate the first use of a high-throughput screen to successfully identify a novel anesthetic chemotype and show mammalian anesthetic activity for members of that chemotype.

High speed imaging for assessment of impact damage in natural fibre biocomposites

NASA Astrophysics Data System (ADS)

Ramakrishnan, Karthik Ram; Corn, Stephane; Le Moigne, Nicolas; Ienny, Patrick; Leger, Romain; Slangen, Pierre R.

2017-06-01

The use of Digital Image Correlation has been generally limited to the estimation of mechanical properties and fracture behaviour at low to moderate strain rates. High speed cameras dedicated to ballistic testing are often used to measure the initial and residual velocities of the projectile but rarely for damage assessment. The evaluation of impact damage is frequently achieved post-impact using visual inspection, ultrasonic C-scan or other NDI methods. Ultra-high speed cameras and developments in image processing have made possible the measurement of surface deformations and stresses in real time during dynamic cracking. In this paper, a method is presented to correlate the force- displacement data from the sensors to the slow motion tracking of the transient failure cracks using real-time high speed imaging. Natural fibre reinforced composites made of flax fibres and polypropylene matrix was chosen for the study. The creation of macro-cracks during the impact results in the loss of stiffness and a corresponding drop in the force history. However, optical instrumentation shows that the initiation of damage is not always evident and so the assessment of damage requires the use of a local approach. Digital Image Correlation is used to study the strain history of the composite and to identify the initiation and progression of damage. The effect of fly-speckled texture on strain measurement by image correlation is also studied. The developed method can be used for the evaluation of impact damage for different composite materials.

Enabling Highly Effective Boiling from Superhydrophobic Surfaces

NASA Astrophysics Data System (ADS)

Allred, Taylor P.; Weibel, Justin A.; Garimella, Suresh V.

2018-04-01

A variety of industrial applications such as power generation, water distillation, and high-density cooling rely on heat transfer processes involving boiling. Enhancements to the boiling process can improve the energy efficiency and performance across multiple industries. Highly wetting textured surfaces have shown promise in boiling applications since capillary wicking increases the maximum heat flux that can be dissipated. Conversely, highly nonwetting textured (superhydrophobic) surfaces have been largely dismissed for these applications as they have been shown to promote formation of an insulating vapor film that greatly diminishes heat transfer efficiency. The current Letter shows that boiling from a superhydrophobic surface in an initial Wenzel state, in which the surface texture is infiltrated with liquid, results in remarkably low surface superheat with nucleate boiling sustained up to a critical heat flux typical of hydrophilic wetting surfaces, and thus upends this conventional wisdom. Two distinct boiling behaviors are demonstrated on both micro- and nanostructured superhydrophobic surfaces based on the initial wetting state. For an initial surface condition in which vapor occupies the interstices of the surface texture (Cassie-Baxter state), premature film boiling occurs, as has been commonly observed in the literature. However, if the surface texture is infiltrated with liquid (Wenzel state) prior to boiling, drastically improved thermal performance is observed; in this wetting state, the three-phase contact line is pinned during vapor bubble growth, which prevents the development of a vapor film over the surface and maintains efficient nucleate boiling behavior.

Hysteresis phenomena of the intelligent driver model for traffic flow

NASA Astrophysics Data System (ADS)

Dahui, Wang; Ziqiang, Wei; Ying, Fan

2007-07-01

We present hysteresis phenomena of the intelligent driver model for traffic flow in a circular one-lane roadway. We show that the microscopic structure of traffic flow is dependent on its initial state by plotting the fraction of congested vehicles over the density, which shows a typical hysteresis loop, and by investigating the trajectories of vehicles on the velocity-over-headway plane. We find that the trajectories of vehicles on the velocity-over-headway plane, which usually show a hysteresis loop, include multiple loops. We also point out the relations between these hysteresis loops and the congested jams or high-density clusters in traffic flow.

The Influence of Parental Control and Parent-Child Relational Qualities on Adolescent Internet Addiction: A 3-Year Longitudinal Study in Hong Kong

PubMed Central

Shek, Daniel T. L.; Zhu, Xiaoqin; Ma, Cecilia M. S.

2018-01-01

This study investigated how parental behavioral control, parental psychological control, and parent-child relational qualities predicted the initial level and rate of change in adolescent internet addiction (IA) across the junior high school years. The study also investigated the concurrent and longitudinal effects of different parenting factors on adolescent IA. Starting from the 2009/2010 academic year, 3,328 Grade 7 students (Mage = 12.59 ± 0.74 years) from 28 randomly selected secondary schools in Hong Kong responded on a yearly basis to a questionnaire measuring multiple constructs including socio-demographic characteristics, perceived parenting characteristics, and IA. Individual growth curve (IGC) analyses showed that adolescent IA slightly decreased during junior high school years. While behavioral control of both parents was negatively related to the initial level of adolescent IA, only paternal behavioral control showed a significant positive relationship with the rate of linear change in IA, suggesting that higher paternal behavioral control predicted a slower decrease in IA. In addition, fathers' and mothers' psychological control was positively associated with the initial level of adolescent IA, but increase in maternal psychological control predicted a faster drop in IA. Finally, parent-child relational qualities negatively and positively predicted the initial level and the rate of change in IA, respectively. When all parenting factors were considered simultaneously, multiple regression analyses revealed that paternal behavioral control and psychological control as well as maternal psychological control and mother-child relational quality were significant concurrent predictors of adolescent IA at Wave 2 and Wave 3. Regarding the longitudinal predicting effects, paternal psychological control and mother-child relational quality at Wave 1 were the two most robust predictors of later adolescent IA at Wave 2 and Wave 3. The above findings underscore the importance of the parent-child subsystem qualities in influencing adolescent IA in the junior high school years. In particular, these findings shed light on the different impacts of fathering and mothering which are neglected in the scientific literature. While the findings based on the levels of IA are consistent with the existing theoretical models, findings on the rate of change are novel. PMID:29765349

The Influence of Parental Control and Parent-Child Relational Qualities on Adolescent Internet Addiction: A 3-Year Longitudinal Study in Hong Kong.

PubMed

Shek, Daniel T L; Zhu, Xiaoqin; Ma, Cecilia M S

2018-01-01

This study investigated how parental behavioral control, parental psychological control, and parent-child relational qualities predicted the initial level and rate of change in adolescent internet addiction (IA) across the junior high school years. The study also investigated the concurrent and longitudinal effects of different parenting factors on adolescent IA. Starting from the 2009/2010 academic year, 3,328 Grade 7 students ( M age = 12.59 ± 0.74 years) from 28 randomly selected secondary schools in Hong Kong responded on a yearly basis to a questionnaire measuring multiple constructs including socio-demographic characteristics, perceived parenting characteristics, and IA. Individual growth curve (IGC) analyses showed that adolescent IA slightly decreased during junior high school years. While behavioral control of both parents was negatively related to the initial level of adolescent IA, only paternal behavioral control showed a significant positive relationship with the rate of linear change in IA, suggesting that higher paternal behavioral control predicted a slower decrease in IA. In addition, fathers' and mothers' psychological control was positively associated with the initial level of adolescent IA, but increase in maternal psychological control predicted a faster drop in IA. Finally, parent-child relational qualities negatively and positively predicted the initial level and the rate of change in IA, respectively. When all parenting factors were considered simultaneously, multiple regression analyses revealed that paternal behavioral control and psychological control as well as maternal psychological control and mother-child relational quality were significant concurrent predictors of adolescent IA at Wave 2 and Wave 3. Regarding the longitudinal predicting effects, paternal psychological control and mother-child relational quality at Wave 1 were the two most robust predictors of later adolescent IA at Wave 2 and Wave 3. The above findings underscore the importance of the parent-child subsystem qualities in influencing adolescent IA in the junior high school years. In particular, these findings shed light on the different impacts of fathering and mothering which are neglected in the scientific literature. While the findings based on the levels of IA are consistent with the existing theoretical models, findings on the rate of change are novel.

Dust coagulation and magnetic field strength in a planet-induced gap subject to MRI turbulence

NASA Astrophysics Data System (ADS)

Carballido, Augusto; Matthews, Lorin; Hyde, Truell

2017-01-01

We investigate the coagulation of dust particles in and around a gap opened by a Jupiter-mass planet. To this end, we carry out a high-resolution magnetohydrodynamic (MHD) simulation of the gap environment, which is turbulent due to the magneto rotational instability. From the MHD simulation, we obtain values of the gas velocities, densities and turbulent stresses close to the gap edge, in one of the two gas streams that accrete onto the planet, and inside the low-density gap. The MHD values are then supplied to a Monte Carlo dust coagulation algorithm, which models grain sticking, compaction and bouncing. We consider two dust populations for each region: one whose initial size distribution is monodisperse, with monomer radius equal to 1 micron, and another one whose initial size distribution follows the Mathis-Rumpl-Nordsieck distribution for interstellar dust grains, with an initial range of monomer radii between 0.5 and 10 microns. Without bouncing, our Monte Carlo calculations show steady growth of dust aggregates in all regions, and the mass-weighted (MW) average porosity of the initially mono disperse population reaches extremely high final values of 98%. The final MW porosities in all other cases without bouncing range from 30% to 82%. The efficiency of compaction is due to high turbulent relative speeds between dust particles. When bouncing is introduced, growth is slowed down in the planetary wake and inside the gap.We also analyze the strength of the magnetic field threading the gaps opened by planets of different sub-Jovian masses. Preliminary results show that, in a gap opened by a large-mass planet (~ 1 MJ), the time-averaged radial profile of the vertical component of the field (Bz) increases sharply inside the gap, and less sharply in the case of less massive planets. In gaps opened by intermediate-mass planets (~ 0.5 — 0.75 MJ), the radial profile of Bz exhibits local maxima in the vicinity of the planet, but not at the gap center.

The snacking rat as model of human obesity: effects of a free-choice high-fat high-sugar diet on meal patterns.

PubMed

la Fleur, S E; Luijendijk, M C M; van der Zwaal, E M; Brans, M A D; Adan, R A H

2014-05-01

Rats subjected to a free-choice high-fat high-sugar (fcHFHS) diet persistently overeat, exhibit increased food-motivated behavior and become overtly obese. Conversely, several studies using a non-choice (nc) high-energy diet showed only an initial increase in food intake with unaltered or reduced food-motivated behavior. This raises the question of the importance of choice in the persistence of hyperphagia in rats on a fcHFHS diet. Meal patterns, food intake and body weight gain were studied in male Wistar rats on free-choice diets with fat and/or sugar and in rats on nc diets with fat and sugar (custom made with ingredients similar to the fcHFHS diet). Rats on a ncHFHS diet initially overconsumed, but reduced intake thereafter, whereas rats on a fcHFHS diet remained hyperphagic. Because half of the sugar intake in the fcHFHS group occurred during the inactive period, we next determined whether sugar intake during the light phase was a necessary requirement for hyperphagia, by restricting access to liquid sugar to either the light or dark period with unlimited access to fat and chow. Results showed that hyperphagia occurred irrespective of the timing of sugar intake. Meal pattern analysis revealed consumption of larger but fewer meals in the ncHFHS group, as well as the fcHF group. Interestingly, meal number was increased in all rats drinking liquid sugar (whether on a fcHFHS or a fcHS diet), whereas a compensatory decrease in meal size was only observed in the fcHS group, but not the fcHFHS group. We hereby show the importance of choice in the observation of fcHFHS diet-induced hyperphagia, which results in increases in meal number due to sugar drinking without any compensatory decrease in meal size. We thus provide a novel dietary model in rats that mimics important features of human overconsumption that have been ignored in rodent models of obesity.

Differential effects of self-esteem and interpersonal competence on humor styles

PubMed Central

McCosker, Bernadette; Moran, Carmen C

2012-01-01

Background In contrast with an early implicit “facilitative hypothesis” of humor, a revised specificity hypothesis predicts that the benefits of humor depend on the specific style of humor used. Information on predictors of these humor styles in turn enhances the ability to predict the effect on well-being. Methods We examined the relationships between interpersonal competence, self-esteem, and different styles of humor, while also examining the contributions of age and gender. Participants (n = 201) aged 18–63 years completed the Rosenberg Self-Esteem Inventory, the Interpersonal Competence Questionnaire, and the Humor Styles Questionnaire, and gave demographic information. Results High self-esteem was associated with higher use of affiliative, aggressive, and self-enhancing humor styles, but lower use of self-defeating humor. High interpersonal competence predicted greater use of affiliative humor, whereas low interpersonal competence predicted greater use of aggressive humor. Further analyses showed that initiation competence predicted affiliative humor (positively) but both initiation competence (positively) and conflict management competence (negatively) predicted aggressive humor. Conclusion The findings that both self-esteem and initiation competence contribute to use of aggressive humor add to knowledge of who is likely to use this potentially harmful humor style. We conclude that a readiness to initiate humorous interactions is not on its own a general and positive attribute contributing to “good” humor. PMID:23180973

Effects of SiO 2 overlayer at initial growth stage of epitaxial Y 2O 3 film growth

NASA Astrophysics Data System (ADS)

Cho, M.-H.; Ko, D.-H.; Choi, Y. G.; Lyo, I. W.; Jeong, K.; Whang, C. N.

2000-12-01

We investigated the dependence of the Y 2O 3 film growth on Si surface at initial growth stage. The reflection high-energy electron diffraction, X-ray scattering, and atomic force microscopy showed that the film crystallinity and morphology strongly depended on whether Si surface contained O or not. In particular, the films grown on oxidized surfaces revealed significant improvement in crystallinity and surface smoothness. A well-ordered atomic structure of Y 2O 3 film was formed on 1.5 nm thick SiO 2 layer with the surface and interfacial roughness markedly enhanced, compared with the film grown on the clean Si surfaces. The epitaxial film on the oxidized Si surface exhibited extremely small mosaic structures at interface, while the film on the clean Si surface displayed an island-like growth with large mosaic structures. The nucleation sites for Y 2O 3 were provided by the reaction between SiO 2 and Y at the initial growth stage. The SiO 2 layer known to hinder crystal growth is found to enhance the nucleation of Y 2O 3, and provides a stable buffer layer against the silicide formation. Thus, the formation of the initial SiO 2 layer is the key to the high-quality epitaxial growth of Y 2O 3 on Si.

Deuterium fractionation and H2D+ evolution in turbulent and magnetized cloud cores

NASA Astrophysics Data System (ADS)

Körtgen, Bastian; Bovino, Stefano; Schleicher, Dominik R. G.; Giannetti, Andrea; Banerjee, Robi

2017-08-01

High-mass stars are expected to form from dense prestellar cores. Their precise formation conditions are widely discussed, including their virial condition, which results in slow collapse for supervirial cores with strong support by turbulence or magnetic fields, or fast collapse for subvirial sources. To disentangle their formation processes, measurements of the deuterium fractions are frequently employed to approximately estimate the ages of these cores and to obtain constraints on their dynamical evolution. We here present 3D magnetohydrodynamical simulations including for the first time an accurate non-equilibrium chemical network with 21 gas-phase species plus dust grains and 213 reactions. With this network we model the deuteration process in fully depleted prestellar cores in great detail and determine its response to variations in the initial conditions. We explore the dependence on the initial gas column density, the turbulent Mach number, the mass-to-magnetic flux ratio and the distribution of the magnetic field, as well as the initial ortho-to-para ratio (OPR) of H2. We find qualitatively good agreement with recent observations of deuterium fractions in quiescent sources. Our results show that deuteration is rather efficient, even when assuming a conservative OPR of 3 and highly subvirial initial conditions, leading to large deuterium fractions already within roughly a free-fall time. We discuss the implications of our results and give an outlook to relevant future investigations.

Re-exposure to low osmolar iodinated contrast media in patients with prior moderate-to-severe hypersensitivity reactions: A multicentre retrospective cohort study.

PubMed

Park, Hye Jung; Park, Jung-Won; Yang, Min-Suk; Kim, Mi-Yeong; Kim, Sae-Hoon; Jang, Gwang Cheon; Nam, Young-Hee; Kim, Gun-Woo; Kim, Sujeong; Park, Hye-Kyung; Jung, Jae-Woo; Park, Jong-Sook; Kang, Hye-Ryun

2017-07-01

To evaluate the outcomes of re-exposure to low-osmolar iodinated contrast medium (LOCM) in patients with a history of moderate-to-severe hypersensitivity reaction (HSR). We retrospectively evaluated a cohort comprising all subjects satisfying the following conditions at 11 centres: (1) experienced a moderate-to-severe HSR to LOCM by December 2014, and (2) underwent contrast-enhanced computed tomography after the initial HSR between January 2014 and December 2014. A total of 150 patients with 328 instances of re-exposure were included; the recurrence rate of HSR was 19.5%. Patients with severe initial HSR exhibited a higher recurrence rate of severe HSR compared to patients with moderate initial HSR, despite more intensive premedication. In the multivariate analysis, the independent risk factors for recurrence of HSR were diabetes, chronic urticaria, drug allergy other than to iodinated contrast media (ICM) and severe initial HSR. The risk of recurrent HSR was 67.1% lower in cases where the implicated ICM was changed to another one (odds ratio: 0.329; P = 0.001). However, steroid premedication did not show protective effects against recurrent HSR. In high-risk patients who have previously experienced a moderate-to-severe initial HSR to LOCM, we should consider changing the implicated ICM to reduce recurrence risk. • In patients with moderate-to-severe HSR, steroid premedication only shows limited effectiveness. • Changing the implicated ICM can reduce the recurrence of HSR to ICM. • Diabetes, chronic urticaria and drug allergies increase the risk of ICM HSR.

Any way you look at it, successful obstacle negotiation needs visually guided on-line foot placement regulation during the approach phase.

PubMed

Patla, Aftab E; Greig, Michael

In the two experiments discussed in this paper we quantified obstacle avoidance performance characteristics carried out open loop (without vision) but with different initial visual sampling conditions and compared it to the full vision condition. The initial visual sampling conditions included: static vision (SV), vision during forward walking for three steps and stopping (FW), vision during forward walking for three steps and not stopping (FW-NS), and vision during backward walking for three steps and stopping (BW). In experiment 1, we compared performance during SV, FW and BW with full vision condition, while in the second experiment we compared performance during FW and FW-NS conditions. The questions we wanted to address are: Is ecologically valid dynamic visual sampling of the environment superior to static visual sampling for open loop obstacle avoidance task? What are the reasons for failure in performing open loop obstacle avoidance task? The results showed that irrespective of the initial visual sampling condition when open loop control is initiated from a standing posture, the success rate was only approximately 50%. The main reason for the high failure rates was not inappropriate limb elevation, but incorrect foot placement before the obstacle. The second experiment showed that it is not the nature of visual sampling per se that influences success rate, but the fact that the open loop obstacle avoidance task is initiated from a standing posture. The results of these two experiments clearly demonstrate the importance of on-line visual information for adaptive human locomotion.

Adsorption of arsenic from aqueous solution using magnetic graphene oxide

NASA Astrophysics Data System (ADS)

Sherlala, A. I. A.; Raman, A. A.; Bello, M. M.

2017-06-01

A binary of graphene oxide (GO) and iron oxide (IO) was prepared and used for the removal of arsenic from aqueous solution. The synthesized compound was characterized using XRD analysis. The prepared composite was used for the adsorption of arsenic from aqueous solution. Central Composite Design was used to design the adsorption experiments and to investigate the effects of operational parameters (initial concentration of arsenic, adsorbent dosage, pH and time) on the adsorption capacity and efficiency. The adsorbent shows a high adsorption capacity for the arsenic. The adsorption efficiency ranges between 33.2 % and 99.95 %. The most significant factors affecting the adsorption capacity were found to be the initial concentration of arsenic and the adsorbent dosage. The initial pH of the solution slightly affects the adsorption capacity, with the maximum adsorption capacity occurring around pH 6 - 7. Thus, the developed adsorbent has a potential for effective removal of arsenic from aqueous solution.

Bullet Impact Safety Study of PBX-9502

NASA Astrophysics Data System (ADS)

Ferranti, Louis

2013-06-01

A new small arms capability for performing bullet impact testing into energetic materials has recently been activated at Lawrence Livermore National Laboratory located in the High Explosives Applications Facility (HEAF). The initial capability includes 0.223, 0.30, and 0.50 testing calibers with the flexibility to add other barrels in the near future. An initial test series has been performed using the 0.50 caliber barrel shooting bullets into targets using the TATB based explosive PBX-9502 and shows an expected non-violent reaction. Future experiments to evaluate the safety of new explosive formulations to bullet impact are planned. A highlight of the new capability along with discussion of the initial experiments to date will be presented including future areas of research. This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

Iterative Refinement of Transmission Map for Stereo Image Defogging Using a Dual Camera Sensor.

PubMed

Kim, Heegwang; Park, Jinho; Park, Hasil; Paik, Joonki

2017-12-09

Recently, the stereo imaging-based image enhancement approach has attracted increasing attention in the field of video analysis. This paper presents a dual camera-based stereo image defogging algorithm. Optical flow is first estimated from the stereo foggy image pair, and the initial disparity map is generated from the estimated optical flow. Next, an initial transmission map is generated using the initial disparity map. Atmospheric light is then estimated using the color line theory. The defogged result is finally reconstructed using the estimated transmission map and atmospheric light. The proposed method can refine the transmission map iteratively. Experimental results show that the proposed method can successfully remove fog without color distortion. The proposed method can be used as a pre-processing step for an outdoor video analysis system and a high-end smartphone with a dual camera system.

Compressive behavior of fine sand.

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

Martin, Bradley E.; Kabir, Md. E.; Song, Bo

2010-04-01

The compressive mechanical response of fine sand is experimentally investigated. The strain rate, initial density, stress state, and moisture level are systematically varied. A Kolsky bar was modified to obtain uniaxial and triaxial compressive response at high strain rates. A controlled loading pulse allows the specimen to acquire stress equilibrium and constant strain-rates. The results show that the compressive response of the fine sand is not sensitive to strain rate under the loading conditions in this study, but significantly dependent on the moisture content, initial density and lateral confinement. Partially saturated sand is more compliant than dry sand. Similar trendsmore » were reported in the quasi-static regime for experiments conducted at comparable specimen conditions. The sand becomes stiffer as initial density and/or confinement pressure increases. The sand particle size become smaller after hydrostatic pressure and further smaller after dynamic axial loading.« less

Iterative Refinement of Transmission Map for Stereo Image Defogging Using a Dual Camera Sensor

PubMed Central

Park, Jinho; Park, Hasil

2017-01-01

Recently, the stereo imaging-based image enhancement approach has attracted increasing attention in the field of video analysis. This paper presents a dual camera-based stereo image defogging algorithm. Optical flow is first estimated from the stereo foggy image pair, and the initial disparity map is generated from the estimated optical flow. Next, an initial transmission map is generated using the initial disparity map. Atmospheric light is then estimated using the color line theory. The defogged result is finally reconstructed using the estimated transmission map and atmospheric light. The proposed method can refine the transmission map iteratively. Experimental results show that the proposed method can successfully remove fog without color distortion. The proposed method can be used as a pre-processing step for an outdoor video analysis system and a high-end smartphone with a dual camera system. PMID:29232826

Exact closed-form solution of the hyperbolic equation of string vibrations with material relaxation properties taken into account

NASA Astrophysics Data System (ADS)

Kudinov, I. V.; Kudinov, V. A.

2014-09-01

The differential equation of damped string vibrations was obtained with the finite speed of extension and strain propagation in the Hooke's law formula taken into account. In contrast to the well-known equations, the obtained equation contains the first and third time derivatives of the displacement and the mixed derivative with respect to the space and time variables. Separation of variables was used to obtain its exact closed-form solution, whose analysis showed that, for large values of the relaxation coefficient, the string return to the initial state after its escape from equilibrium is accompanied by high-frequency low-amplitude damped vibrations, which occur on the initial time interval only in the region of positive displacements. And in the limit, for some large values of the relaxation coefficient, the string return to the initial state occurs practically without any oscillatory process.

Reaction Buildup of PBX Explosives JOB-9003 under Different Initiation Pressures

NASA Astrophysics Data System (ADS)

Zhang, Xu; Wang, Yan-fei; Hung, Wen-bin; Gu, Yan; Zhao, Feng; Wu, Qiang; Yu, Xin; Yu, Heng

2017-04-01

Aluminum-based embedded multiple electromagnetic particle velocity gauge technique has been developed in order to measure the shock initiation behavior of JOB-9003 explosives. In addition, another gauge element called a shock tracker has been used to monitor the progress of the shock front as a function of time, thus providing a position-time trajectory of the wave front as it moves through the explosive sample. The data are used to determine the position and time for shock to detonation transition. All the experimental results show that: the rising-up time of Al-based electromagnetic particle velocity gauge was very fast and less than 20 ns; the reaction buildup velocity profiles and the position-time for shock to detonation transition of HMX-based PBX explosive JOB-9003 with 1-8 mm depth from the origin of impact plane under different initiation pressures are obtained with high accuracy.

The Classroom Observation Schedule to Measure Intentional Communication (COSMIC): an observational measure of the intentional communication of children with autism in an unstructured classroom setting.

PubMed

Pasco, Greg; Gordon, Rosanna K; Howlin, Patricia; Charman, Tony

2008-11-01

The Classroom Observation Schedule to Measure Intentional Communication (COSMIC) was devised to provide ecologically valid outcome measures for a communication-focused intervention trial. Ninety-one children with autism spectrum disorder aged 6 years 10 months (SD 16 months) were videoed during their everyday snack, teaching and free play activities. Inter-rater reliability was high and relevant items showed significant associations with comparable items from concurrent Autism Diagnostic Observation Schedule-Generic (Lord et al. 2000, J Autism Dev Disord 30(3):205-223) assessments. In a subsample of 28 children initial differences in rates of initiations, initiated speech/vocalisation and commenting were predictive of language and communication competence 15 months later. Results suggest that the use of observational measures of intentional communication in natural settings is a valuable assessment strategy for research and clinical practice.

Effects of novelty on behavior in the adolescent and adult rat.

PubMed

Stansfield, Kirstie H; Kirstein, Cheryl L

2006-01-01

Adolescence is a time of high-risk behavior and increased exploration. This developmental period is marked by a greater probability of initiating drug use and is associated with an increased risk to develop addiction and dependency in adulthood. Human adolescents are predisposed towards an increased likelihood of risk taking behaviors (Zuckerman, 1986), including drug use or initiation. The purpose of the study was to examine differences in developmental risk taking behaviors. Adolescent and adult animals were exposed to a novel stimulus in a familiar environment to assess impulsive behaviors, novelty preference, and exploratory behaviors. Adolescent animals had greater novelty-induced locomotor activity, greater novelty preference, and showed higher approach and exploratory behaviors compared to adult animals. These data support the notion that adolescents may be predisposed toward sensation seeking and consequently, are more likely to engage in risk-taking behaviors, such as drug use initiation. Copyright 2005 Wiley Periodicals, Inc.

A novel orthoimage mosaic method using the weighted A* algorithm for UAV imagery

NASA Astrophysics Data System (ADS)

Zheng, Maoteng; Zhou, Shunping; Xiong, Xiaodong; Zhu, Junfeng

2017-12-01

A weighted A* algorithm is proposed to select optimal seam-lines in orthoimage mosaic for UAV (Unmanned Aircraft Vehicle) imagery. The whole workflow includes four steps: the initial seam-line network is firstly generated by standard Voronoi Diagram algorithm; an edge diagram is then detected based on DSM (Digital Surface Model) data; the vertices (conjunction nodes) of initial network are relocated since some of them are on the high objects (buildings, trees and other artificial structures); and, the initial seam-lines are finally refined using the weighted A* algorithm based on the edge diagram and the relocated vertices. The method was tested with two real UAV datasets. Preliminary results show that the proposed method produces acceptable mosaic images in both the urban and mountainous areas, and is better than the result of the state-of-the-art methods on the datasets.

Li2S/Carbon Nanocomposite Strips from a Low-Temperature Conversion of Li2SO4 as High-Performance Lithium-Sulfur Cathodes

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

Ye, Fangmin; Noh, Hyungjun; Lee, Jin Hong

2018-03-12

Carbothermal conversion of Li2SO4 provides a cost-effective strategy to fabricate high-capacity Li2S cathodes, however, Li2S cathodes derived from Li2SO4 at high temperatures (> 800 oC), having high crystallinity and large crystal size, result in a low utilization of Li2S. Here, we report a Li2SO4/poly(vinyl alcohol)-derived Li2S/Carbon nanocomposite (Li2S@C) strips at a record low temperature of 635 oC. These Li2S@C nanocomposite strips as a cathode shows a low initial activation potential (2.63 V), a high initial discharge capacity (805 mAh g-1 Li2S) and a high cycling stability (0.2 C and 1 C). These improvedresults could be ascribed to the nano-sized Li2Smore » particles as well as their low crystallinity due to the PVA-induced carbon network and the low conversion temperature, respectively. An XPS analysis reveals that the C=C and C=O bonds derived from the carbonization of PVA can promote the conversion of Li2SO4 at the low temperature.« less

Malachite Green Adsorption by Spent Coffee Grounds

NASA Astrophysics Data System (ADS)

Syamimie Atirah Mat, Siti; Zati Hanani Syed Zuber, Sharifah; Rahim, Siti Kartini Enche Ab; Sohaimi, Khairunissa Syairah Ahmad; Halim, Noor Amirah Abdul; Fauziah Zainudin, Nor; Aida Yusoff, Nor; Munirah Rohaizad, Nor; Hidayah Ishak, Noor; Anuar, Adilah; Sarip, Mohd Sharizan Md

2018-03-01

In this work, the ability of spent coffee grounds (SCG) as a low-cost adsorbent to remove malachite green (MG) from aqueous solutions was studied. Batch adsorption tests were carried out to observe the effect of various experimental parameters such as contact time, initial concentration of malachite green and adsorbent dosage on the removal of dye. The results obtained show that the percentage of dye removal will decreased with the increased of initial concentration of dye in the range of 50 mg/L to 250 mg/L. Besides, percentage removal of dye was also found to be increased as the contact time increased until it reached equilibrium condition. The results also showed that the adsorbent dosage in range of 0.2 g to 1.0 g is proportional to the percentage removal of malachite green dye. Study on the kinetic adsorption and isotherm adsorption has also been investigated. The adsorption isotherm data were described by Langmuir isotherm with high-correlation coefficients while the experimental data showed the pseudo-second-order kinetics model was the best model for the adsorption of MG by SCG with the coefficients of correlation R2 > 0.9978.

Genomic epidemiology reveals multiple introductions of Zika virus into the United States

NASA Astrophysics Data System (ADS)

Grubaugh, Nathan D.; Ladner, Jason T.; Kraemer, Moritz U. G.; Dudas, Gytis; Tan, Amanda L.; Gangavarapu, Karthik; Wiley, Michael R.; White, Stephen; Thézé, Julien; Magnani, Diogo M.; Prieto, Karla; Reyes, Daniel; Bingham, Andrea M.; Paul, Lauren M.; Robles-Sikisaka, Refugio; Oliveira, Glenn; Pronty, Darryl; Barcellona, Carolyn M.; Metsky, Hayden C.; Baniecki, Mary Lynn; Barnes, Kayla G.; Chak, Bridget; Freije, Catherine A.; Gladden-Young, Adrianne; Gnirke, Andreas; Luo, Cynthia; Macinnis, Bronwyn; Matranga, Christian B.; Park, Daniel J.; Qu, James; Schaffner, Stephen F.; Tomkins-Tinch, Christopher; West, Kendra L.; Winnicki, Sarah M.; Wohl, Shirlee; Yozwiak, Nathan L.; Quick, Joshua; Fauver, Joseph R.; Khan, Kamran; Brent, Shannon E.; Reiner, Robert C.; Lichtenberger, Paola N.; Ricciardi, Michael J.; Bailey, Varian K.; Watkins, David I.; Cone, Marshall R.; Kopp, Edgar W.; Hogan, Kelly N.; Cannons, Andrew C.; Jean, Reynald; Monaghan, Andrew J.; Garry, Robert F.; Loman, Nicholas J.; Faria, Nuno R.; Porcelli, Mario C.; Vasquez, Chalmers; Nagle, Elyse R.; Cummings, Derek A. T.; Stanek, Danielle; Rambaut, Andrew; Sanchez-Lockhart, Mariano; Sabeti, Pardis C.; Gillis, Leah D.; Michael, Scott F.; Bedford, Trevor; Pybus, Oliver G.; Isern, Sharon; Palacios, Gustavo; Andersen, Kristian G.

2017-06-01

Zika virus (ZIKV) is causing an unprecedented epidemic linked to severe congenital abnormalities. In July 2016, mosquito-borne ZIKV transmission was reported in the continental United States; since then, hundreds of locally acquired infections have been reported in Florida. To gain insights into the timing, source, and likely route(s) of ZIKV introduction, we tracked the virus from its first detection in Florida by sequencing ZIKV genomes from infected patients and Aedes aegypti mosquitoes. We show that at least 4 introductions, but potentially as many as 40, contributed to the outbreak in Florida and that local transmission is likely to have started in the spring of 2016—several months before its initial detection. By analysing surveillance and genetic data, we show that ZIKV moved among transmission zones in Miami. Our analyses show that most introductions were linked to the Caribbean, a finding corroborated by the high incidence rates and traffic volumes from the region into the Miami area. Our study provides an understanding of how ZIKV initiates transmission in new regions.

Alteration in the contents of unsaturated fatty acids in dnaA mutants of Escherichia coli.

PubMed

Suzuki, E; Kondo, T; Makise, M; Mima, S; Sakamoto, K; Tsuchiya, T; Mizushima, T

1998-04-01

DnaA protein, the initiator of chromosomal DNA replication in Escherichia coli, has a high affinity for acidic phospholipids containing unsaturated fatty acids. We have examined here the fatty acid composition of phospholipids in dnaA mutants. A temperature-sensitive dnaA46 mutant showed a lower level of unsaturation of fatty acids (ratio of unsaturated to saturated fatty acids) at 42 degrees C (non-permissive temperature) and at 37 degrees C (semi-permissive temperature), but not at 28 degrees C (permissive temperature), compared with the wild-type strain. Plasmid complementation analysis revealed that the dnaA46 mutation is responsible for the phenotype. Other temperature-sensitive dnaA mutants showed similar results. On the other hand, a cold-sensitive dnaAcos mutant, in which over-initiation of DNA replication occurs at low temperature (28 degrees C), showed a higher level of unsaturation of fatty acids at 28 degrees C. Based on these observations, we discuss the role of phospholipids in the regulation of the activity of DnaA protein.

Simulation of Shock-Shock Interaction in Parsec-Scale Jets

NASA Astrophysics Data System (ADS)

Fromm, Christian M.; Perucho, Manel; Ros, Eduardo; Mimica, Petar; Savolainen, Tuomas; Lobanov, Andrei P.; Zensus, J. Anton

The analysis of the radio light curves of the blazar CTA 102 during its 2006 flare revealed a possible interaction between a standing shock wave and a traveling one. In order to better understand this highly non-linear process, we used a relativistic hydrodynamic code to simulate the high energy interaction and its related emission. The calculated synchrotron emission from these simulations showed an increase in turnover flux density, Sm, and turnover frequency, νm, during the interaction and decrease to its initial values after the passage of the traveling shock wave.

Sickle cell crisis leading to extensive necrosis in a low-grade glioma and masquerading high-grade lesion.

PubMed

Agrawal, Amit; Balpande, D N; Khan, A; Vagh, S J; Shukla, Samarth; Chopra, Sumit

2008-01-01

A 9-year-old female child presented with rapid neurological deterioration. Clinical features and imaging findings were suggestive of high-grade malignancy, and hematological investigations were suggestive of sickle cell trait. Histopathology showed features of low-grade malignancy and extensive intratumoral sickling. We hypothesize that the vicious cycle of hypoxia, sickling, thrombosis, ischemia and infarction resulted in the extensive tumor necrosis in the present case causing the initial symptoms and rapid deterioration in the condition of the patient. Copyright 2008 S. Karger AG, Basel.

Post-filamentation high-intensive light channels formation upon ultrashort laser pulses self-focusing in air

NASA Astrophysics Data System (ADS)

Geints, Yu. E.; Ionin, A. A.; Mokrousova, D. V.; Seleznev, L. V.; Sinitsyn, D. V.; Sunchugasheva, E. S.; Zemlyanov, A. A.

2017-01-01

Experimental and theoretical study of the post-filamentation stage of focused high-power Ti:Sa laser pulses in air is presented. Angular divergence of the laser beam, as well as angular and spatial characteristics of specific spatially localized light structures, the post-filament channels (PFCs), under different initial focusing conditions and laser beam energy are investigated. We show that PFC angular divergence is always less than that of the whole laser beam and tends to decrease with laser pulse energy increase and beam focal length elongation.

A high performance hybrid battery based on aluminum anode and LiFePO4 cathode.

PubMed

Sun, Xiao-Guang; Bi, Zhonghe; Liu, Hansan; Fang, Youxing; Bridges, Craig A; Paranthaman, M Parans; Dai, Sheng; Brown, Gilbert M

2016-01-28

A novel hybrid battery utilizing an aluminum anode, a LiFePO4 cathode and an acidic ionic liquid electrolyte based on 1-ethyl-3-methylimidazolium chloride (EMImCl) and aluminum trichloride (AlCl3) (EMImCl-AlCl3, 1-1.1 in molar ratio) with or without LiAlCl4 is proposed. The hybrid ion battery delivers an initial high capacity of 160 mA h g(-1) at a current rate of C/5. It also shows good rate capability and cycling performance.

A high performance hybrid battery based on aluminum anode and LiFePO 4 cathode

DOE PAGES

Sun, Xiao-Guang; Bi, Zhonghe; Liu, Hansan; ...

2015-12-07

A unique battery hybrid utilizes an aluminum anode, a LiFePO 4 cathode and an acidic ionic liquid electrolyte based on 1-ethyl-3-methylimidazolium chloride (EMImCl) and aluminum trichloride (AlCl 3) (EMImCl-AlCl 3, 1-1.1 in molar ratio) with or without LiAlCl 4 is proposed. This hybrid ion battery delivers an initial high capacity of 160 mAh g -1 at a current rate of C/5. It also shows good rate capability and cycling performance.

Sphingolipids in Congenital Diaphragmatic Hernia; Results from an International Multicenter Study

PubMed Central

Snoek, Kitty G.; Reiss, Irwin K. M.; Tibboel, Jeroen; van Rosmalen, Joost; Capolupo, Irma; van Heijst, Arno; Schaible, Thomas; Post, Martin; Tibboel, Dick

2016-01-01

Background Congenital diaphragmatic hernia is a severe congenital anomaly with significant mortality and morbidity, for instance chronic lung disease. Sphingolipids have shown to be involved in lung injury, but their role in the pathophysiology of chronic lung disease has not been explored. We hypothesized that sphingolipid profiles in tracheal aspirates could play a role in predicting the mortality/ development of chronic lung disease in congenital diaphragmatic hernia patients. Furthermore, we hypothesized that sphingolipid profiles differ between ventilation modes; conventional mechanical ventilation versus high-frequency oscillation. Methods Sphingolipid levels in tracheal aspirates were determined at days 1, 3, 7 and 14 in 72 neonates with congenital diaphragmatic hernia, born after > 34 weeks gestation at four high-volume congenital diaphragmatic hernia centers. Data were collected within a multicenter trial of initial ventilation strategy (NTR 1310). Results 36 patients (50.0%) died or developed chronic lung disease, 34 patients (47.2%) by stratification were initially ventilated by conventional mechanical ventilation and 38 patients (52.8%) by high-frequency oscillation. Multivariable logistic regression analysis with correction for side of the defect, liver position and observed-to-expected lung-to-head ratio, showed that none of the changes in sphingolipid levels were significantly associated with mortality /development of chronic lung disease. At day 14, long-chain ceramides 18:1 and 24:0 were significantly elevated in patients initially ventilated by conventional mechanical ventilation compared to high-frequency oscillation. Conclusions We could not detect significant differences in temporal sphingolipid levels in congenital diaphragmatic hernia infants with mortality/development of chronic lung disease versus survivors without development of CLD. Elevated levels of ceramides 18:1 and 24:0 in the conventional mechanical ventilation group when compared to high-frequency oscillation could probably be explained by high peak inspiratory pressures and remodeling of the alveolar membrane. PMID:27159222

Influence of High Cycle Thermal Loads on Thermal Fatigue Behavior of Thick Thermal Barrier Coatings

NASA Technical Reports Server (NTRS)

Zhu, Dongming; Miller, Robert A.

1997-01-01

Thick thermal barrier coating systems in a diesel engine experience severe thermal Low Cycle Fatigue (LCF) and High Cycle Fatigue (HCF) during engine operation. In the present study, the mechanisms of fatigue crack initiation and propagation, as well as of coating failure, under thermal loads which simulate engine conditions, are investigated using a high power CO2 laser. In general, surface vertical cracks initiate early and grow continuously under LCF and HCF cyclic stresses. It is found that in the absence of interfacial oxidation, the failure associated with LCF is closely related to coating sintering and creep at high temperatures, which induce tensile stresses in the coating after cooling. Experiments show that the HCF cycles are very damaging to the coating systems. The combined LCF and HCF tests produced more severe coating surface cracking, microspallation and accelerated crack growth, as compared to the pure LCF test. It is suggested that the HCF component cannot only accelerate the surface crack initiation, but also interact with the LCF by contributing to the crack growth at high temperatures. The increased LCF stress intensity at the crack tip due to the HCF component enhances the subsequent LCF crack growth. Conversely, since a faster HCF crack growth rate will be expected with lower effective compressive stresses in the coating, the LCF cycles also facilitate the HCF crack growth at high temperatures by stress relaxation process. A surface wedging model has been proposed to account for the HCF crack growth in the coating system. This mechanism predicts that HCF damage effect increases with increasing temperature swing, the thermal expansion coefficient and the elastic modulus of the ceramic coating, as well as the HCF interacting depth. A good agreement has been found between the analysis and experimental evidence.

Role of a looming-sensitive neuron in triggering the defense behavior of the praying mantis Tenodera aridifolia.

PubMed

Sato, Keiichiro; Yamawaki, Yoshifumi

2014-08-01

In responses to looming objects, the praying mantis shows a defense behavior, which consists of retracting forelegs under the prothorax. The role of a looming-sensitive neuron in triggering this behavior was investigated by simultaneously recording the activity and behavioral responses of the neuron. The mantis initiated the defense behavior earlier in response to larger and slower looming stimuli. The time remaining to collision at defense initiation was linearly correlated with the ratio of the half-size of an approaching object to its speed (l/|v|), suggesting that the defense behavior occurred a fixed delay after the stimuli had reached a fixed angular threshold. Furthermore, the results suggested that high-frequency spikes of the looming-sensitive neuron were involved in triggering the defense behavior: the distribution of maximum firing rate for trials with defense was shifted to larger rates compared with trials without defense; the firing rate of the neuron exceeded 150 Hz ∼100 ms before the defense initiation regardless of stimulus parameters; when a looming stimulus ceased approach prematurely, high-frequency spikes were removed, and the occurrence of defense was reduced. Copyright © 2014 the American Physiological Society.