Sample records for acceleration probe snap

  1. SNAP: Small Next-generation Atmospheric Probe Concept

    NASA Astrophysics Data System (ADS)

    Sayanagi, K. M.; Dillman, R. A.; Atkinson, D. H.; Li, J.; Saikia, S.; Simon, A. A.; Spilker, T. R.; Wong, M. H.; Hope, D.

    2017-12-01

    We present a concept for a small, atmospheric probe that could be flexibly added to future missions that orbit or fly-by a giant planet as a secondary payload, which we call the Small Next-generation Atmospheric Probe (SNAP). SNAP's main scientific objectives are to determine the vertical distribution of clouds and cloud-forming chemical species, thermal stratification, and wind speed as a function of depth. As a case study, we present the advantages, cost and risk of adding SNAP to the future Uranus Orbiter and Probe flagship mission; in combination with the mission's main probe, SNAP would perform atmospheric in-situ measurements at a second location, and thus enable and enhance the scientific objectives recommended by the 2013 Planetary Science Decadal Survey and the 2014 NASA Science Plan to determine atmospheric spatial variabilities. We envision that the science objectives can be achieved with a 30-kg entry probe 0.5m in diameter (less than half the size of the Galileo probe) that reaches 5-bar pressure-altitude and returns data to Earth via the carrier spacecraft. As the baseline instruments, the probe will carry an Atmospheric Structure Instrument (ASI) that measures the temperature, pressure and acceleration, a carbon nanotube-based NanoChem atmospheric composition sensor, and an Ultra-Stable Oscillator (USO) to conduct a Doppler Wind Experiment (DWE). We also catalog promising technologies currently under development that will strengthen small atmospheric entry probe missions in the future. While SNAP is applicable to multiple planets, we examine the feasibility, benefits and impacts of adding SNAP to the Uranus Orbiter and Probe flagship mission. Our project is supported by NASA PSDS3 grant NNX17AK31G.

  2. Small Next-Generation Atmospheric Probe (SNAP) Concept

    NASA Technical Reports Server (NTRS)

    Sayanagi, K. M.; Dillman, R. A.; Simon, A. A.; Atkinson, D. H.; Wong, M. H.; Spilker, T. R.; Saikia, S.; Li, J.; Hope, D.

    2017-01-01

    We present the Small Next-Generation Atmospheric Probe (SNAP) as a secondary payload concept for future missions to giant planets. As a case study, we examine the advantages, cost and risk of adding SNAP to the future Uranus Orbiter and Probe flag-ship mission; in combination with the missions main probe, SNAP would perform atmospheric in-situ measurements at a second location.

  3. Beyond velocity and acceleration: jerk, snap and higher derivatives

    NASA Astrophysics Data System (ADS)

    Eager, David; Pendrill, Ann-Marie; Reistad, Nina

    2016-11-01

    The higher derivatives of motion are rarely discussed in the teaching of classical mechanics of rigid bodies; nevertheless, we experience the effect not only of acceleration, but also of jerk and snap. In this paper we will discuss the third and higher order derivatives of displacement with respect to time, using the trampolines and theme park roller coasters to illustrate this concept. We will also discuss the effects on the human body of different types of acceleration, jerk, snap and higher derivatives, and how they can be used in physics education to further enhance the learning and thus the understanding of classical mechanics concepts.

  4. A fluorogenic probe for SNAP-tagged plasma membrane proteins based on the solvatochromic molecule Nile Red.

    PubMed

    Prifti, Efthymia; Reymond, Luc; Umebayashi, Miwa; Hovius, Ruud; Riezman, Howard; Johnsson, Kai

    2014-03-21

    A fluorogenic probe for plasma membrane proteins based on the dye Nile Red and SNAP-tag is introduced. It takes advantage of Nile Red, a solvatochromic molecule highly fluorescent in an apolar environment, such as cellular membranes, but almost dark in a polar aqueous environment. The probe possesses a tuned affinity for membranes allowing its Nile Red moiety to insert into the lipid bilayer of the plasma membrane, becoming fluorescent, only after its conjugation to a SNAP-tagged plasma membrane protein. The fluorogenic character of the probe was demonstrated for different SNAP-tag fusion proteins, including the human insulin receptor. This work introduces a new approach for generating a powerful turn-on probe for "no-wash" labeling of plasma membrane proteins with numerous applications in bioimaging.

  5. LED Illuminators for the SNAP Calibration

    NASA Astrophysics Data System (ADS)

    Misra, Amit; Baptista, B.; Mufson, S.; Mostek, N.

    2007-12-01

    The Supernova Acceleration Probe, or SNAP, is a proposed satellite mission that will study dark energy to better understand what is driving the universe's accelerated expansion. One of the goals of SNAP is to control systematic color uncertainties to less than 2%. The work described here is directed at the development of a flight calibration illumination system for SNAP that minimizes systematic errors in color. The system is based on LEDs as the illumination lamps. LEDs are compact, long-lived, and low power illuminators, which make them attractive for space missions lasting several years. This poster discusses optical measurements of pulsed, thermally controlled LEDs obtained from commercial vendors. Measurements over short (over the span of one day) and long (over the span of weeks) time scales have shown that the irradiance of the LEDs we tested is constant at the 0.3% level. In these measurements we paid particular attention to the influence of junction heating. Measurements of LED irradiance versus the duty cycle of the pulsed LED show that in general the LED irradiance increases as the junction temperature increases. Additionally, the FWHM of the spectrum also increases as the temperature increases. However, measurements of LED irradiance versus temperature as regulated a by a thermal controller circuit, show that the LED irradiance decreases as the temperature increases. This work has been supported by the National Science Foundation under grant AST-0452975 (REU-Site to Indiana U.).

  6. Probing electron acceleration and x-ray emission in laser-plasma accelerators

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

    Thaury, C.; Ta Phuoc, K.; Corde, S.

    2013-06-15

    While laser-plasma accelerators have demonstrated a strong potential in the acceleration of electrons up to giga-electronvolt energies, few experimental tools for studying the acceleration physics have been developed. In this paper, we demonstrate a method for probing the acceleration process. A second laser beam, propagating perpendicular to the main beam, is focused on the gas jet few nanosecond before the main beam creates the accelerating plasma wave. This second beam is intense enough to ionize the gas and form a density depletion, which will locally inhibit the acceleration. The position of the density depletion is scanned along the interaction lengthmore » to probe the electron injection and acceleration, and the betatron X-ray emission. To illustrate the potential of the method, the variation of the injection position with the plasma density is studied.« less

  7. Revised SNAP III Training Manual

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

    Moss, Calvin Elroy; Gonzales, Samuel M.; Myers, William L.

    The Shielded Neutron Assay Probe (SNAP) technique was developed to determine the leakage neutron source strength of a radioactive object. The original system consisted of an Eberline TM Mini-scaler and discrete neutron detector. The system was operated by obtaining the count rate with the Eberline TM instrument, determining the absolute efficiency from a graph, and calculating the neutron source strength by hand. In 2003 the SNAP III, shown in Figure 1, was designed and built. It required the operator to position the SNAP, and then measure the source-to-detector and detectorto- reflector distances. Next the operator entered the distance measurements andmore » started the data acquisition. The SNAP acquired the required count rate and then calculated and displayed the leakage neutron source strength (NSS). The original design of the SNAP III is described in SNAP III Training Manual (ER-TRN-PLN-0258, Rev. 0, January 2004, prepared by William Baird) This report describes some changes that have been made to the SNAP III. One important change is the addition of a LEMO connector to provide neutron detection output pulses for input to the MC-15. This feature is useful in active interrogation with a neutron generator because the MC-15 has the capability to only record data when it is not gated off by a pulse from the neutron generator. This avoids recording of a lot of data during the generator pulses that are not useful. Another change was the replacement of the infrared RS-232 serial communication output by a similar output via a 4-pin LEMO connector. The current document includes a more complete explanation of how to estimate the amount of moderation around a neutron-emitting source.« less

  8. Fluorescent labeling of SNAP-tagged proteins in cells.

    PubMed

    Lukinavičius, Gražvydas; Reymond, Luc; Johnsson, Kai

    2015-01-01

    One of the most prominent self-labeling tags is SNAP-tag. It is an in vitro evolution product of the human DNA repair protein O (6)-alkylguanine-DNA alkyltransferase (hAGT) that reacts specifically with benzylguanine (BG) and benzylchloropyrimidine (CP) derivatives, leading to covalent labeling of SNAP-tag with a synthetic probe (Gronemeyer et al., Protein Eng Des Sel 19:309-316, 2006; Curr Opin Biotechnol 16:453-458, 2005; Keppler et al., Nat Biotechnol 21:86-89, 2003; Proc Natl Acad Sci U S A 101:9955-9959, 2004). SNAP-tag is well suited for the analysis and quantification of fused target protein using fluorescence microscopy techniques. It provides a simple, robust, and versatile approach to the imaging of fusion proteins under a wide range of experimental conditions.

  9. Building the Case for SNAP: Creation of Multi-Band, Simulated Images With Shapelets

    NASA Technical Reports Server (NTRS)

    Ferry, Matthew A.

    2005-01-01

    Dark energy has simultaneously been the most elusive and most important phenomenon in the shaping of the universe. A case for a proposed space-telescope called SNAP (SuperNova Acceleration Probe) is being built, a crucial component of which is image simulations. One method for this is "Shapelets," developed at Caltech. Shapelets form an orthonormal basis and are uniquely able to represent realistic space images and create new images based on real ones. Previously, simulations were created using the Hubble Deep Field (HDF) as a basis Set in one band. In this project, image simulations are created.using the 4 bands of the Hubble Ultra Deep Field (UDF) as a basis set. This provides a better basis for simulations because (1) the survey is deeper, (2) they have a higher resolution, and (3) this is a step closer to simulating the 9 bands of SNAP. Image simulations are achieved by detecting sources in the UDF, decomposing them into shapelets, tweaking their parameters in realistic ways, and recomposing them into new images. Morphological tests were also run to verify the realism of the simulations. They have a wide variety of uses, including the ability to create weak gravitational lensing simulations.

  10. SNAP-23 regulates phagosome formation and maturation in macrophages

    PubMed Central

    Sakurai, Chiye; Hashimoto, Hitoshi; Nakanishi, Hideki; Arai, Seisuke; Wada, Yoh; Sun-Wada, Ge-Hong; Wada, Ikuo; Hatsuzawa, Kiyotaka

    2012-01-01

    Synaptosomal associated protein of 23 kDa (SNAP-23), a plasma membrane–localized soluble N-ethylmaleimide–sensitive factor attachment protein receptor (SNARE), has been implicated in phagocytosis by macrophages. For elucidation of its precise role in this process, a macrophage line overexpressing monomeric Venus–tagged SNAP-23 was established. These cells showed enhanced Fc receptor–mediated phagocytosis. Detailed analyses of each process of phagocytosis revealed a marked increase in the production of reactive oxygen species within phagosomes. Also, enhanced accumulation of a lysotropic dye, as well as augmented quenching of a pH-sensitive fluorophore were observed. Analyses of isolated phagosomes indicated the critical role of SNAP-23 in the functional recruitment of the NADPH oxidase complex and vacuolar-type H+-ATPase to phagosomes. The data from the overexpression experiments were confirmed by SNAP-23 knockdown, which demonstrated a significant delay in phagosome maturation and a reduction in uptake activity. Finally, for analyzing whether phagosomal SNAP-23 entails a structural change in the protein, an intramolecular Förster resonance energy transfer (FRET) probe was constructed, in which the distance within a TagGFP2-TagRFP was altered upon close approximation of the N-termini of its two SNARE motifs. FRET efficiency on phagosomes was markedly enhanced only when VAMP7, a lysosomal SNARE, was coexpressed. Taken together, our results strongly suggest the involvement of SNAP-23 in both phagosome formation and maturation in macrophages, presumably by mediating SNARE-based membrane traffic. PMID:23087210

  11. A Drosophila SNAP-25 null mutant reveals context-dependent redundancy with SNAP-24 in neurotransmission.

    PubMed Central

    Vilinsky, Ilya; Stewart, Bryan A; Drummond, James; Robinson, Iain; Deitcher, David L

    2002-01-01

    The synaptic protein SNAP-25 is an important component of the neurotransmitter release machinery, although its precise function is still unknown. Genetic analysis of other synaptic proteins has yielded valuable information on their role in synaptic transmission. In this study, we performed a mutagenesis screen to identify new SNAP-25 alleles that fail to complement our previously isolated recessive temperature-sensitive allele of SNAP-25, SNAP-25(ts). In a screen of 100,000 flies, 26 F(1) progeny failed to complement SNAP-25(ts) and 21 of these were found to be null alleles of SNAP-25. These null alleles die at the pharate adult stage and electroretinogram recordings of these animals reveal that synaptic transmission is blocked. At the third instar larval stage, SNAP-25 nulls exhibit nearly normal neurotransmitter release at the neuromuscular junction. This is surprising since SNAP-25(ts) larvae exhibit a much stronger synaptic phenotype. Our evidence indicates that a related protein, SNAP-24, can substitute for SNAP-25 at the larval stage in SNAP-25 nulls. However, if a wild-type or mutant form of SNAP-25 is present, then SNAP-24 does not appear to take part in neurotransmitter release at the larval NMJ. These results suggest that the apparent redundancy between SNAP-25 and SNAP-24 is due to inappropriate genetic substitution. PMID:12242238

  12. SNAP E&T

    ERIC Educational Resources Information Center

    Lower-Basch, Elizabeth

    2014-01-01

    This document provides an overview of Supplemental Nutrition Assistance Program Employment and Training (SNAP E&T). SNAP E&T is a funding source that allows states to provide employment and training and related supportive services to individuals receiving Supplemental Nutrition Assistance Program (SNAP, formerly known as food stamps)…

  13. Rapid optical imaging of EGF receptor expression with a single-chain antibody SNAP-tag fusion protein.

    PubMed

    Kampmeier, Florian; Niesen, Judith; Koers, Alexander; Ribbert, Markus; Brecht, Andreas; Fischer, Rainer; Kiessling, Fabian; Barth, Stefan; Thepen, Theo

    2010-10-01

    The epidermal growth factor receptor (EGFR) is overexpressed in several types of cancer and its inhibition can effectively inhibit tumour progression. The purpose of this study was to design an EGFR-specific imaging probe that combines efficient tumour targeting with rapid systemic clearance to facilitate non-invasive assessment of EGFR expression. Genetic fusion of a single-chain antibody fragment with the SNAP-tag produced a 48-kDa antibody derivative that can be covalently and site-specifically labelled with substrates containing 0 (6)-benzylguanine. The EGFR-specific single-chain variable fragment (scFv) fusion protein 425(scFv)SNAP was labelled with the near infrared (NIR) dye BG-747, and its accumulation, specificity and kinetics were monitored using NIR fluorescence imaging in a subcutaneous pancreatic carcinoma xenograft model. The 425(scFv)SNAP fusion protein accumulates rapidly and specifically at the tumour site. Its small size allows efficient renal clearance and a high tumour to background ratio (TBR) of 33.2 +/- 6.3 (n = 4) 10 h after injection. Binding of the labelled antibody was efficiently competed with a 20-fold excess of unlabelled probe, resulting in an average TBR of 6 +/- 1.35 (n = 4), which is similar to that obtained with a non-tumour-specific probe (5.44 +/- 1.92, n = 4). When compared with a full-length antibody against EGFR (cetuximab), 425(scFv)SNAP-747 showed significantly higher TBRs and complete clearance 72 h post-injection. The 425(scFv)SNAP fusion protein combines rapid and specific targeting of EGFR-positive tumours with a versatile and robust labelling technique that facilitates the attachment of fluorophores for use in optical imaging. The same approach could be used to couple a chelating agent for use in nuclear imaging.

  14. Snapping hip: imaging and treatment.

    PubMed

    Lee, Kenneth S; Rosas, Humberto G; Phancao, Jean-Pierre

    2013-07-01

    Snapping hip, or coxa saltans, presents as an audible or palpable snapping that occurs around the hip during movement and can be associated with or without pain. The prevalence of snapping hip is estimated to occur in up to 10% of the general population, but it is especially seen in athletes such as dancers, soccer players, weight lifters, and runners. Although the snapping sound can be readily heard, the diagnostic cause may be a clinical challenge. The causes of snapping hip have been divided into two distinct categories: extra-articular and intra-articular. Extra-articular snapping hip can be further subdivided into external and internal causes. Advances in imaging techniques have improved the diagnostic accuracy of the various causes of snapping hip, mainly by providing real-time imaging evaluation of moving structures during the snapping phase. Image-guided treatments have also been useful in the diagnostic work-up of snapping hip given the complexity and multitude of causes of hip pain. We discuss the common and uncommon causes of snapping hip, the advanced imaging techniques that now give us a better understanding of the underlying mechanism, and an image-guided diagnostic and therapeutic algorithm that helps to identify surgical candidates. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

  15. Phosphorylation of SNAP-23 at Ser95 causes a structural alteration and negatively regulates Fc receptor-mediated phagosome formation and maturation in macrophages.

    PubMed

    Sakurai, Chiye; Itakura, Makoto; Kinoshita, Daiki; Arai, Seisuke; Hashimoto, Hitoshi; Wada, Ikuo; Hatsuzawa, Kiyotaka

    2018-05-17

    SNAP-23 is a plasma membrane-localized SNARE protein involved in Fc receptor (FcR)-mediated phagocytosis. However, the regulatory mechanism underlying its function remains elusive. Using phosphorylation specific-antibodies, SNAP-23 was found to be phosphorylated at Ser95 in macrophages. To understand the role of this phosphorylation, we established macrophage lines overexpressing the non-phosphorylatable S95A or the phospho-mimicking S95D mutation. The efficiency of phagosome formation and maturation was severely reduced in SNAP-23-S95D-overexpressing cells. To examine whether phosphorylation at Ser95 affected SNAP-23 structure, we constructed intramolecular Förster resonance energy transfer (FRET) probes of SNAP-23 designed to evaluate the approximation of the N-termini of the two SNARE motifs. Interestingly, a high FRET efficiency was detected on the membrane when the S95D probe was used, indicating that phosphorylation at Ser95 caused a dynamic structural shift to the closed form. Co-expression of IκB kinase (IKK) 2 enhanced the FRET efficiency of the wild-type probe on the phagosome membrane. Furthermore, the enhanced phagosomal FRET signal in interferon-γ-activated macrophages was largely dependent on IKK2, and this kinase mediated a delay in phagosome-lysosome fusion. These results suggested that SNAP-23 phosphorylation at Ser95 played an important role in the regulation of SNARE-dependent membrane fusion during FcR-mediated phagocytosis.

  16. Over-damped elastic `snap-through'

    NASA Astrophysics Data System (ADS)

    Gomez, Michael; Moulton, Derek E.; Vella, Dominic

    Elastic `snap-through' occurs when a system is in an equilibrium state that either disappears or becomes unstable as a control parameter varies. The switch from one state to another is generally rapid and hence is used to generate fast motions in biology and engineering. While the conditions under which simple elastic objects undergo snap-through have been reasonably well studied, how fast snapping happens is much less well understood. Recently, it has been shown that snap-through can be subject to critical slowing down near the snapping transition, so that the dynamics may be slow even in the absence of viscous damping. Here, we study the interaction of snap-through with the flow of a viscous fluid. We begin by showing how snap-through may be used to create a channel whose hydraulic conductivity changes discontinuously in response to fluid flow. We then study the dynamics of snap-through for an elastic element embedded in a viscous fluid, which is typical of pull-in instabilities in micro-electromechanical systems (MEMS).

  17. Nu-Way Snaps and Snap Leads: an Important Connection in the History of Behavior Analysis.

    PubMed

    Escobar, Rogelio; Lattal, Kennon A

    2014-10-01

    Beginning in the early 1950s, the snap lead became an integral and ubiquitous component of the programming of electromechanical modules used in behavioral experiments. It was composed of a Nu-Way snap connector on either end of a colored electrical wire. Snap leads were used to connect the modules to one another, thereby creating the programs that controlled contingencies, arranged reinforcers, and recorded behavior in laboratory experiments. These snap leads populated operant conditioning laboratories from their inception until the turn of the twenty-first century. They allowed quick and flexible programming because of the ease with which they could be connected, stacked, and removed. Thus, the snap lead was integral to the research activity that constituted the experimental analysis of behavior for more than five decades. This review traces the history of the snap lead from the origins of the snap connector in Birmingham, England, in the late eighteenth century, through the use of snaps connected to wires during the Second World War, to its adoption in operant laboratories, and finally to its demise in the digital age.

  18. Florida snapping turtle

    NASA Image and Video Library

    2007-10-22

    A rare photo of a Florida snapping turtle out in the open on Beach Road, near NASA's Kennedy Space Center. Found only in Florida and Georgia, this species is related to the common snapping turtle. It is considered a dangerous turtle because it can snap very quickly with its extremely strong jaws. Its tail, which is almost as long as its shell, has saw-edges along the top. The shell also has rough points down the middle. The shell is tan to dark brown and may have green algae growing on it. It can grow to 17 inches long and weigh 45 pounds. Snapping turtles usually live in ponds under the shadows and don’t like to rest in the sun like most turtles. They eat almost anything: water bugs, fish, lizards, small birds, mice, plants and even dead animals.

  19. Florida snapping turtle

    NASA Image and Video Library

    2007-10-22

    A rare photo of a Florida snapping turtle out in the open on Beach Road, near NASA's Kennedy Space Center. Found only in Florida and Georgia, this species is related to the common snapping turtle. It is considered a dangerous turtle because it can snap very quickly with its extremely strong jaws. Its tail, which is almost as long as its shell, has saw-edges along the top. The shell also has rough points down the middle. The shell is tan to dark brown and may have green algae growing on it. It can grow to 17 inches long and weigh 45 pounds. Snapping turtles usually live in ponds under the shadows and don’t like to rest in the sun like most turtles. They eat almost anything: water bugs, fish, lizards, small birds, mice, plants and even dead animals

  20. Temperature effects on snapping performance in the common snapper Chelydra serpentina (Reptilia, Testudines).

    PubMed

    Vervust, Bart; Brecko, Jonathan; Herrel, Anthony

    2011-01-01

    Studies on the effect of temperature on whole-animal performance traits other than locomotion are rare. Here we investigate the effects of temperature on the performance of the turtle feeding apparatus in a defensive context. We measured bite force and the kinematics of snapping in the Common Snapping Turtle (Chelydra serpentina) over a wide range of body temperatures. Bite force performance was thermally insensitive over the broad range of temperatures typically experienced by these turtles in nature. In contrast, neck extension (velocity, acceleration, and deceleration) and jaw movements (velocity, acceleration, and deceleration) showed clear temperature dependence with peak acceleration and deceleration capacity increasing with increasing temperatures. Our results regarding the temperature dependence of defensive behavior are reflected by the ecology and overall behavior of this species. These data illustrate the necessity for carefully controlling T(b) when carrying out behavioral and functional studies on turtles as temperature affects the velocity, acceleration, and deceleration of jaw and neck extension movements. More generally, these data add to the limited but increasing number of studies showing that temperature may have important effects on feeding and defensive performance in ectotherms. © 2010 Wiley-Liss, Inc.

  1. Snap-in compressible biomedical electrode

    NASA Technical Reports Server (NTRS)

    Frost, J. D., Jr.; Hillman, C. E., Jr. (Inventor)

    1977-01-01

    A replaceable, prefilled electrode enclosed in a plastic seal and suitably adapted for attachment to a reusable, washable cap having snaps thereon is disclosed. The apparatus is particularly adapted for quick positioning of electrodes to obtain an EEG. The individual electrodes are formed of a sponge body which is filled with a conductive electrolyte gel during manufacture. The sponge body is adjacent to a base formed of a conductive plastic material. The base has at its center a male gripper snap. The cap locates the female snap to enable the electrode to be positioned. The electrode can be stored and used quickly by attaching to the female gripper snap. The snap is correctly positioned and located by mounting it in a stretchable cap. The cap is reusable with new electrodes for each use. The electrolyte gel serves as the contact electrode to achieve a good ohmic contact with the scalp.

  2. Elastocapillary snapping

    NASA Astrophysics Data System (ADS)

    Antkowiak, Arnaud; Fargette, Aurelie; Neukirch, Sebastien

    2010-11-01

    An elastica buckled in the form of an arch is subjected to a transverse force. Above a critical load value, the buckling mode is switched and the elastica takes the form of a reversed arch. This is the well-known snap-through phenomenon which has been extensively studied in solid mechanics. Here, we revisit this phenomenon and show that capillary forces may promote snapping of a buckled polymer strip. We report detailed experiments of this new paradigm for elasto-capillary interactions, and the obtained results are in close agreement with a simple elastic stability theory.

  3. Snapping plicae associated with radiocapitellar chondromalacia.

    PubMed

    Antuna, S A; O'Driscoll, S W

    2001-05-01

    Painful snapping of the elbow joint is usually attributed to intra-articular loose bodies, instability, or medial dislocation of the triceps muscle over the medial epicondyle. We report our experience with 14 patients who were treated arthroscopically for snapping elbow that was found to be caused by hypertrophic synovial folds associated with radiocapitellar chondromalacia. Case series. The records of 14 patients who were treated arthroscopically for painful snapping elbows caused by intra-articular plicae were reviewed. There were 6 women and 8 men with an average age of 36 years (range, 27 to 48 years). Nine patients had had some type of trauma to the joint. Four patients had been previously diagnosed with lateral epicondylitis and 5 with intra-articular loose bodies. The average time from initial onset of symptoms to treatment was 13 months (range, 8 to 36 months). Average follow-up was 24 months (range, 6 to 66 months). All patients complained of painful snapping in the posterolateral or anterolateral aspect of the elbow. The snapping occurred between 90 degrees and 110 degrees of flexion with the forearm in pronation. In 7 patients, the snapping was reproducible by passively flexing the pronated elbow, which we refer to as the flexion-pronation test. At the time of arthroscopic surgery, all patients had a thickened synovial plica that would snap back and forward over the radial head, usually associated with a chondromalacic area on the radial head. Twelve patients had complete relief of their snapping after surgery. One patient in whom there was associated posterolateral rotatory elbow instability did not improve. One patient became asymptomatic for 4 years but then had recurrence of her symptoms, which persisted despite 2 subsequent arthroscopies. The presence of synovial plicae in the radiocapitellar joint must be considered in the differential diagnosis of painful snapping elbow. Arthroscopy confirms the diagnosis and allows excision of the plica.

  4. Ubuntu Core Snaps for Science

    NASA Astrophysics Data System (ADS)

    Wyngaard, J.

    2017-12-01

    A key challenge in the burgeoning sector of IoT (Internet of Things) is ensuring device and communication security. Ubuntu Core's approach to this is the use of 'snaps'. Along side this growth, scientists are increasingly utilising the many new low cost sensors now available. This work prototypes the use of snaps as a possible avenue to reducing the barrier to entry for scientific use of these low cost sensors while also ensuring proper meta-data is captured. Snaps are contained applications that have been signed. This means that a snap application is unable to read or write to any area of the system beyond its assigned reach, thereby significantly limiting the possible impact of any break in security higher up the stack. Further, application and system updates are automatically verified as authentic before being applied. Additionally, on an embedded system running Ubuntu Core the hardware interface (Gadget), kernel, and OS (Core) are all also snaps and therefore also have acquired these same gains. The result is an architecture that enables: (1) Secure, robust, remote automatic updates of both the OS and applications. (2) A user friendly deployment mechanism.(3) A easy to maintain means of supporting multiple platforms. The above is primarily targeted at non-academic domains, however, it is proposed that the Scientific community can benefit from it too. This work therefore prototypes a snap for sensors on board a small Unmanned Aircraft System (sUAS). For demonstration purposes this snap specifically targets connecting a popular low cost CO2 meter to a Raspberry Pi3 and the popular open source sUAS autopilot Arducopter.

  5. Significant New Alternatives Policy (SNAP)

    EPA Pesticide Factsheets

    These webpages provide information on EPA’s Significant New Alternatives Policy (SNAP) program which evaluates substitutes for ozone-depleting substances in major industrial use sectors. The SNAP program promotes a smooth transition to safer alternatives.

  6. SNAP-25 IN NEUROPSYCHIATRIC DISORDERS

    PubMed Central

    Corradini, Irene; Verderio, Claudia; Sala, Mariaelvina; Wilson, Michael C.; Matteoli, Michela

    2009-01-01

    SNAP-25 is plasma membrane protein which, together with syntaxin and the synaptic vesicle protein VAMP/synaptobrevin, forms the SNARE docking complex for regulated exocytosis. SNAP-25 also modulates different voltage-gated calcium channels, representing therefore a multifunctional protein that plays essential roles in neurotransmitter release at different steps. Recent genetic studies of human populations and of some mouse models implicate that alterations in SNAP-25 gene structure, expression and/or function may contribute directly to these distinct neuropsychiatric and neurological disorders. PMID:19161380

  7. The Supernovae Analysis Application (SNAP)

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

    Bayless, Amanda J.; Fryer, Christopher Lee; Wollaeger, Ryan Thomas

    The SuperNovae Analysis aPplication (SNAP) is a new tool for the analysis of SN observations and validation of SN models. SNAP consists of a publicly available relational database with observational light curve, theoretical light curve, and correlation table sets with statistical comparison software, and a web interface available to the community. The theoretical models are intended to span a gridded range of parameter space. The goal is to have users upload new SN models or new SN observations and run the comparison software to determine correlations via the website. There are problems looming on the horizon that SNAP is beginningmore » to solve. For example, large surveys will discover thousands of SNe annually. Frequently, the parameter space of a new SN event is unbounded. SNAP will be a resource to constrain parameters and determine if an event needs follow-up without spending resources to create new light curve models from scratch. Second, there is no rapidly available, systematic way to determine degeneracies between parameters, or even what physics is needed to model a realistic SN. The correlations made within the SNAP system are beginning to solve these problems.« less

  8. The Supernovae Analysis Application (SNAP)

    DOE PAGES

    Bayless, Amanda J.; Fryer, Christopher Lee; Wollaeger, Ryan Thomas; ...

    2017-09-06

    The SuperNovae Analysis aPplication (SNAP) is a new tool for the analysis of SN observations and validation of SN models. SNAP consists of a publicly available relational database with observational light curve, theoretical light curve, and correlation table sets with statistical comparison software, and a web interface available to the community. The theoretical models are intended to span a gridded range of parameter space. The goal is to have users upload new SN models or new SN observations and run the comparison software to determine correlations via the website. There are problems looming on the horizon that SNAP is beginningmore » to solve. For example, large surveys will discover thousands of SNe annually. Frequently, the parameter space of a new SN event is unbounded. SNAP will be a resource to constrain parameters and determine if an event needs follow-up without spending resources to create new light curve models from scratch. Second, there is no rapidly available, systematic way to determine degeneracies between parameters, or even what physics is needed to model a realistic SN. The correlations made within the SNAP system are beginning to solve these problems.« less

  9. The Supernovae Analysis Application (SNAP)

    NASA Astrophysics Data System (ADS)

    Bayless, Amanda J.; Fryer, Chris L.; Wollaeger, Ryan; Wiggins, Brandon; Even, Wesley; de la Rosa, Janie; Roming, Peter W. A.; Frey, Lucy; Young, Patrick A.; Thorpe, Rob; Powell, Luke; Landers, Rachel; Persson, Heather D.; Hay, Rebecca

    2017-09-01

    The SuperNovae Analysis aPplication (SNAP) is a new tool for the analysis of SN observations and validation of SN models. SNAP consists of a publicly available relational database with observational light curve, theoretical light curve, and correlation table sets with statistical comparison software, and a web interface available to the community. The theoretical models are intended to span a gridded range of parameter space. The goal is to have users upload new SN models or new SN observations and run the comparison software to determine correlations via the website. There are problems looming on the horizon that SNAP is beginning to solve. For example, large surveys will discover thousands of SNe annually. Frequently, the parameter space of a new SN event is unbounded. SNAP will be a resource to constrain parameters and determine if an event needs follow-up without spending resources to create new light curve models from scratch. Second, there is no rapidly available, systematic way to determine degeneracies between parameters, or even what physics is needed to model a realistic SN. The correlations made within the SNAP system are beginning to solve these problems.

  10. The Curious Acoustic Behavior of Estuarine Snapping Shrimp: Temporal Patterns of Snapping Shrimp Sound in Sub-Tidal Oyster Reef Habitat.

    PubMed

    Bohnenstiehl, DelWayne R; Lillis, Ashlee; Eggleston, David B

    2016-01-01

    Ocean soundscapes convey important sensory information to marine life. Like many mid-to-low latitude coastal areas worldwide, the high-frequency (>1.5 kHz) soundscape of oyster reef habitat within the West Bay Marine Reserve (36°N, 76°W) is dominated by the impulsive, short-duration signals generated by snapping shrimp. Between June 2011 and July 2012, a single hydrophone deployed within West Bay was programmed to record 60 or 30 seconds of acoustic data every 15 or 30 minutes. Envelope correlation and amplitude information were then used to count shrimp snaps within these recordings. The observed snap rates vary from 1500-2000 snaps per minute during summer to <100 snaps per minute during winter. Sound pressure levels are positively correlated with snap rate (r = 0.71-0.92) and vary seasonally by ~15 decibels in the 1.5-20 kHz range. Snap rates are positively correlated with water temperatures (r = 0.81-0.93), as well as potentially influenced by climate-driven changes in water quality. Light availability modulates snap rate on diurnal time scales, with most days exhibiting a significant preference for either nighttime or daytime snapping, and many showing additional crepuscular increases. During mid-summer, the number of snaps occurring at night is 5-10% more than predicted by a random model; however, this pattern is reversed between August and April, with an excess of up to 25% more snaps recorded during the day in the mid-winter. Diurnal variability in sound pressure levels is largest in the mid-winter, when the overall rate of snapping is at its lowest, and the percentage difference between daytime and nighttime activity is at its highest. This work highlights our lack of knowledge regarding the ecology and acoustic behavior of one of the most dominant soniforous invertebrate species in coastal systems. It also underscores the necessity of long-duration, high-temporal-resolution sampling in efforts to understand the bioacoustics of animal behaviors and

  11. The Curious Acoustic Behavior of Estuarine Snapping Shrimp: Temporal Patterns of Snapping Shrimp Sound in Sub-Tidal Oyster Reef Habitat

    PubMed Central

    Bohnenstiehl, DelWayne R.; Lillis, Ashlee; Eggleston, David B.

    2016-01-01

    Ocean soundscapes convey important sensory information to marine life. Like many mid-to-low latitude coastal areas worldwide, the high-frequency (>1.5 kHz) soundscape of oyster reef habitat within the West Bay Marine Reserve (36°N, 76°W) is dominated by the impulsive, short-duration signals generated by snapping shrimp. Between June 2011 and July 2012, a single hydrophone deployed within West Bay was programmed to record 60 or 30 seconds of acoustic data every 15 or 30 minutes. Envelope correlation and amplitude information were then used to count shrimp snaps within these recordings. The observed snap rates vary from 1500–2000 snaps per minute during summer to <100 snaps per minute during winter. Sound pressure levels are positively correlated with snap rate (r = 0.71–0.92) and vary seasonally by ~15 decibels in the 1.5–20 kHz range. Snap rates are positively correlated with water temperatures (r = 0.81–0.93), as well as potentially influenced by climate-driven changes in water quality. Light availability modulates snap rate on diurnal time scales, with most days exhibiting a significant preference for either nighttime or daytime snapping, and many showing additional crepuscular increases. During mid-summer, the number of snaps occurring at night is 5–10% more than predicted by a random model; however, this pattern is reversed between August and April, with an excess of up to 25% more snaps recorded during the day in the mid-winter. Diurnal variability in sound pressure levels is largest in the mid-winter, when the overall rate of snapping is at its lowest, and the percentage difference between daytime and nighttime activity is at its highest. This work highlights our lack of knowledge regarding the ecology and acoustic behavior of one of the most dominant soniforous invertebrate species in coastal systems. It also underscores the necessity of long-duration, high-temporal-resolution sampling in efforts to understand the bioacoustics of animal behaviors

  12. Dynamics of snapping beams and jumping poppers

    NASA Astrophysics Data System (ADS)

    Pandey, A.; Moulton, D. E.; Vella, D.; Holmes, D. P.

    2014-01-01

    We consider the dynamic snapping instability of elastic beams and shells. Using the Kirchhoff rod and Föppl-von Kármán plate equations, we study the stability, deformation modes, and snap-through dynamics of an elastic arch with clamped boundaries and subject to a concentrated load. For parameters typical of everyday and technological applications of snapping, we show that the stretchability of the arch plays a critical role in determining not only the post-buckling mode of deformation but also the timescale of snapping and the frequency of the arch's vibrations about its final equilibrium state. We show that the growth rate of the snap-through instability and its subsequent ringing frequency can both be interpreted physically as the result of a sound wave in the material propagating over a distance comparable to the length of the arch. Finally, we extend our analysis of the ringing frequency of indented arches to understand the “pop” heard when everted shell structures snap-through to their stable state. Remarkably, we find that not only are the scaling laws for the ringing frequencies in these two scenarios identical but also the respective prefactors are numerically close; this allows us to develop a master curve for the frequency of ringing in snapping beams and shells.

  13. Quantitative mass spectrometry reveals changes in SNAP-25 isoforms in schizophrenia

    PubMed Central

    Barakauskas, Vilte E; Moradian, Annie; Barr, Alasdair M.; Beasley, Clare L; Rosoklija, Gorazd; Mann, J John; Ilievski, Boro; Stankov, Aleksandar; Dwork, Andrew J; Falkai, Peter; Morin, Gregg B; Honer, William G

    2016-01-01

    SNAP-25 and syntaxin are presynaptic terminal SNARE proteins altered in amount and function in schizophrenia. In the ventral caudate, we observed 32% lower SNAP-25 and 26% lower syntaxin, but greater interaction between the two proteins using an in vitro assay. SNAP-25 has two isoforms, SNAP-25A and B, differing by only 9 amino acids, but with different effects on neurotransmission. A quantitative mass spectrometry assay was developed to measure total SNAP-25, and proportions of SNAP-25A and B. The assay had a good linear range (50- to 150-fold) and coefficient of variation (4.5%). We studied ventral caudate samples from patients with schizophrenia (n=15) previously reported to have lower total SNAP-25 than controls (n=13). We confirmed 27% lower total SNAP-25 in schizophrenia, and observed 31% lower SNAP-25A (P = 0.002) with 20% lower SNAP-25B amounts (P = 0.10). Lower SNAP-25A amount correlated with greater SNAP-25-syntaxin protein-protein interactions (r = -0.41, P = 0.03); the level of SNAP-25B did not. Administration of haloperidol or clozapine to rats did not mimic the changes found in schizophrenia. The findings suggest that lower levels of SNAP-25 in schizophrenia may represent a greater effect of the illness on the SNAP-25A isoform. This in turn could contribute to the greater interaction between SNAP25 and syntaxin, and possibly disturb neurotransmission in the illness. PMID:26971072

  14. SNAP Benefits: Can an Adequate Benefit Be Defined?123

    PubMed Central

    Yaktine, Ann L.; Caswell, Julie A.

    2014-01-01

    The Supplemental Nutrition Assistance Program (SNAP) increases the food purchasing power of participating households. A committee convened by the Institute of Medicine (IOM) examined the question of whether it is feasible to define SNAP allotment adequacy. Total resources; individual, household, and environmental factors; and SNAP program characteristics that affect allotment adequacy were identified from a framework developed by the IOM committee. The committee concluded that it is feasible to define SNAP allotment adequacy; however, such a definition must take into account the degree to which participants’ total resources and individual, household, and environmental factors influence the purchasing power of SNAP benefits and the impact of SNAP program characteristics on the calculation of the dollar value of the SNAP allotment. The committee recommended that the USDA Food and Nutrition Service investigate ways to incorporate these factors and program characteristics into research aimed at defining allotment adequacy. PMID:24425718

  15. How the Venus flytrap actively snaps: hydrodynamic measurements at the cellular level

    NASA Astrophysics Data System (ADS)

    Colombani, Mathieu; Forterre, Yoel; GEP Team

    2012-11-01

    Although they lack muscle, plants have evolved a remarkable range of mechanisms to create rapid motion, from the rapid folding of sensitive plants to seed dispersal. Of these spectacular examples that have long fascinated scientists, the carnivorous plant Venus flytrap, whose leaves snap together in a fraction of second to capture insects, has long been a paradigm for study. Recently, we have shown that this motion involves a snap-buckling instability due to the shell-like geometry of the leaves of the trap. However, the origin of the movement that allows the plant to cross the instability threshold and actively bend remains largely unknown. In this study, we investigate this active motion using a micro-fluidic pressure probe that gives direct hydraulic and mechanical measurements at the cellular level (osmotic pressure, cell membrane permeability, cell wall elasticity). Our results challenge the role of osmotically-driven water flows usually put forward to explain Venus flytrap's active closure.

  16. Snap evaporation of droplets on smooth topographies.

    PubMed

    Wells, Gary G; Ruiz-Gutiérrez, Élfego; Le Lirzin, Youen; Nourry, Anthony; Orme, Bethany V; Pradas, Marc; Ledesma-Aguilar, Rodrigo

    2018-04-11

    Droplet evaporation on solid surfaces is important in many applications including printing, micro-patterning and cooling. While seemingly simple, the configuration of evaporating droplets on solids is difficult to predict and control. This is because evaporation typically proceeds as a "stick-slip" sequence-a combination of pinning and de-pinning events dominated by static friction or "pinning", caused by microscopic surface roughness. Here we show how smooth, pinning-free, solid surfaces of non-planar topography promote a different process called snap evaporation. During snap evaporation a droplet follows a reproducible sequence of configurations, consisting of a quasi-static phase-change controlled by mass diffusion interrupted by out-of-equilibrium snaps. Snaps are triggered by bifurcations of the equilibrium droplet shape mediated by the underlying non-planar solid. Because the evolution of droplets during snap evaporation is controlled by a smooth topography, and not by surface roughness, our ideas can inspire programmable surfaces that manage liquids in heat- and mass-transfer applications.

  17. The surprising dynamics of a chain on a pulley: lift off and snapping

    PubMed Central

    Audoly, Basile

    2016-01-01

    The motion of weights attached to a chain or string moving on a frictionless pulley is a classic problem of introductory physics used to understand the relationship between force and acceleration. Here, we consider the dynamics of the chain when one of the weights is removed and, thus, one end is pulled with constant acceleration. This simple change has dramatic consequences for the ensuing motion: at a finite time, the chain ‘lifts off’ from the pulley, and the free end subsequently accelerates faster than the end that is pulled. Eventually, the chain undergoes a dramatic reversal of curvature reminiscent of the crack or snap, of a whip. We combine experiments, numerical simulations and theoretical arguments to explain key aspects of this dynamical problem. PMID:27436987

  18. The surprising dynamics of a chain on a pulley: lift off and snapping.

    PubMed

    Brun, P-T; Audoly, Basile; Goriely, Alain; Vella, Dominic

    2016-06-01

    The motion of weights attached to a chain or string moving on a frictionless pulley is a classic problem of introductory physics used to understand the relationship between force and acceleration. Here, we consider the dynamics of the chain when one of the weights is removed and, thus, one end is pulled with constant acceleration. This simple change has dramatic consequences for the ensuing motion: at a finite time, the chain 'lifts off' from the pulley, and the free end subsequently accelerates faster than the end that is pulled. Eventually, the chain undergoes a dramatic reversal of curvature reminiscent of the crack or snap, of a whip. We combine experiments, numerical simulations and theoretical arguments to explain key aspects of this dynamical problem.

  19. Rewarding Healthy Food Choices in SNAP: Behavioral Economic Applications

    PubMed Central

    Richards, Michael R; Sindelar, Jody L

    2013-01-01

    Context American obesity rates continue to escalate, but an effective policy response remains elusive. Specific changes to the Supplemental Nutrition Assistance Program (SNAP) have been proposed as one way to improve nutrition and combat obesity among lower-income populations. While current SNAP proposals hold promise, some important challenges still remain. Methods We discuss the four most common recommendations for changes to SNAP and their benefits and limitations. We then propose three new delivery options for SNAP that take advantage of behavioral economic insights and encourage the selection of healthy foods. Findings Although the existing proposals could help SNAP recipients, they often do not address some important behavioral impediments to buying healthy foods. We believe that behavioral economics can be used to design alternative policies with several advantages, although we recognize and discuss some of their limitations. The first proposal rewards healthy purchases with more SNAP funds and provides an additional incentive to maintain healthier shopping patterns. The second proposal uses the opportunity to win prizes to reward healthy food choices, and the prizes further support healthier habits. The final proposal simplifies healthy food purchases by allowing individuals to commit their SNAP benefits to more nutritious selections in advance. Conclusions Reforming the delivery structure of SNAP's benefits could help improve nutrition, weight, and overall health of lower-income individuals. We advocate for more and diverse SNAP proposals, which should be tested and, possibly, combined. Their implementation, however, would require political will, administrative capacity, and funding. PMID:23758515

  20. Endoscopic treatment of snapping hips, iliotibial band, and iliopsoas tendon.

    PubMed

    Ilizaliturri, Victor M; Camacho-Galindo, Javier

    2010-06-01

    Indications for endoscopic surgery of the hip have expanded recently. The technique has found a clear indication in the management of snapping hip syndromes, both external snapping hip and internal snapping hip. Even though the snapping hips (external and internal) share a common name, they are very different in origin. The external snapping hip is produced by the iliotibial band snapping over the prominence of the greater trochanter during flexion and extension. Indication for surgical treatment is painful snapping with failure of conservative treatment. The endoscopic technique is designed to release the iliotibial band producing a diamond shape defect on the iliotibial band lateral to the greater trochanter. The defect allows the greater trochanter to move freely without snapping. The greater trochanteric bursa is resected through the defect and the abductor tendons inspected. This procedure is performed without traction and usually only the peritrochanteric space is accessed. If necessary, hip arthroscopy can also be performed. There is limited literature regarding the results of endoscopic treatment for the external snapping hip syndrome, but early reports are encouraging. The internal snapping hip syndrome is produced by the iliopsoas tendon snapping over the iliopectineal eminence or the femoral head. The snapping phenomenon usually occurs with extension of the hip from a flexed position of more than 90 degree. Two different endoscopic techniques have been described to treat this condition. Iliopsoas tendon release at the level of the hip joint, with this technique the iliopsoas bursa is accessed through an anterior hip capsulotomy and is frequently referred to as a transcapsular release. The second technique is a release at the insertion of the iliopsoas tendon on the lesser trochanter, with this technique the iliospaos bursa is accessed directly. In every report the iliopsoas tendon release has been combined with arthroscopy of the hip joint. It has been

  1. SNAP Cuts Put Youth at Risk

    ERIC Educational Resources Information Center

    Lower-Basch, Elizabeth

    2013-01-01

    In a typical month in 2011, the Supplemental Nutrition Assistance Program (SNAP, formerly known as the Food Stamp Program) served 4.3 million low-income young adults ages 18-24, helping them buy needed groceries. This brief report demonstrates the detrimental impact the cuts proposed to SNAP in the House-passed Farm bill (H.R. 3102)--which is now…

  2. Global Curvature Buckling and Snapping of Spherical Shells.

    NASA Astrophysics Data System (ADS)

    Pezzulla, Matteo; Stoop, Norbert; Steranka, Mark; Bade, Abdikhalaq; Trejo, Miguel; Holmes, Douglas

    A spherical shell under external pressure will eventually buckle locally through the development of a dimple. However, when a free spherical shell is subject to variations in natural curvature, it will either buckle globally or snap towards a buckled configuration. We study the similarities and differences between pressure and curvature instabilities in spherical shells. We show how the critical buckling natural curvature is largely independent of the thinness and half-angle of the shell, while the critical snapping natural curvature grows linearly with the half-angle. As a result, we demonstrate how a critical half-angle, depending only on the thinness of the shell, sets the threshold between two different kinds of snapping: as a rule of thumb, shallow shells snap into everted shells, while deep shells snap into buckled shells. As the developed models are purely geometrical, the results are applicable to a large variety of stimuli and scales. NSF CAREER CMMI-1454153.

  3. Defining SNAP by cross-sectional and longitudinal definitions of neurodegeneration.

    PubMed

    Wisse, L E M; Das, S R; Davatzikos, C; Dickerson, B C; Xie, S X; Yushkevich, P A; Wolk, D A

    2018-01-01

    Suspected non-Alzheimer's pathophysiology (SNAP) is a biomarker driven designation that represents a heterogeneous group in terms of etiology and prognosis. SNAP has only been identified by cross-sectional neurodegeneration measures, whereas longitudinal measures might better reflect "active" neurodegeneration and might be more tightly linked to prognosis. We compare neurodegeneration defined by cross-sectional 'hippocampal volume' only (SNAP/L-) versus both cross-sectional and longitudinal 'hippocampal atrophy rate' (SNAP/L+) and investigate how these definitions impact prevalence and the clinical and biomarker profile of SNAP in Mild Cognitive Impairment (MCI). 276 MCI patients from ADNI-GO/2 were designated amyloid "positive" (A+) or "negative" (A-) based on their florbetapir scan and neurodegeneration 'positive' or 'negative' based on cross-sectional hippocampal volume and longitudinal hippocampal atrophy rate. 74.1% of all SNAP participants defined by the cross-sectional definition of neurodegeneration also met the longitudinal definition of neurodegeneration, whereas 25.9% did not. SNAP/L+ displayed larger white matter hyperintensity volume, a higher conversion rate to dementia over 5 years and a steeper decline on cognitive tasks compared to SNAP/L- and the A- CN group. SNAP/L- had more abnormal values on neuroimaging markers and worse performance on cognitive tasks than the A- CN group, but did not show a difference in dementia conversion rate or longitudinal cognition. Using a longitudinal definition of neurodegeneration in addition to a cross-sectional one identifies SNAP participants with significant cognitive decline and a worse clinical prognosis for which cerebrovascular disease may be an important driver.

  4. Specifically and wash-free labeling of SNAP-tag fused proteins with a hybrid sensor to monitor local micro-viscosity.

    PubMed

    Wang, Chao; Song, Xinbo; Chen, Lingcheng; Xiao, Yi

    2017-05-15

    Viscosity, as one of the major factors of intracellular microenvironment, influences the function of proteins. To detect local micro-viscosity of a protein, it is a precondition to apply a viscosity sensor for specifically target to proteins. However, all the reported small-molecule probes are just suitable for sensing/imaging of macro-viscosity in biological fluids of entire cells or organelles. To this end, we developed a hybrid sensor BDP-V BG by connecting a viscosity-sensitive boron-dipyrromethene (BODIPY) molecular rotor (BDP-V) to O 6 -benzylguanine (BG) for specific detection of local micro-viscosity of SNAP-tag fused proteins. We measured and calculated the reaction efficiency between the sensor and SNAP-tag protein in vitro to confirm the high labeling specificity. We also found that the labeling reaction results in a 53-fold fluorescence enhancement for the rotor, which qualifies it as a wash-free sensor with ignorable background fluorescence. The high sensitivity of protein labeled sensor (BDP-V-SNAP) to the changes of local viscosity was evaluated by detecting the enhancement of fluorescence lifetimes. Further, with the sensor BDP-V BG, we achieved high specific labeling of cells expressing two SNAP-tag fused proteins (nuclear histone H2B and mitochondrial COX8A). Two-photon excited fluorescence lifetime imaging revealed that, the micro-viscosities nearby the SNAP-tag fused two proteins are distinct. The different changes of local micro-viscosity of SNAP-tag fused histone protein in apoptosis induced by three nucleus-targeted drugs were also characterized for the first time. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. Is cosmic acceleration proven by local cosmological probes?

    NASA Astrophysics Data System (ADS)

    Tutusaus, I.; Lamine, B.; Dupays, A.; Blanchard, A.

    2017-06-01

    Context. The cosmological concordance model (ΛCDM) matches the cosmological observations exceedingly well. This model has become the standard cosmological model with the evidence for an accelerated expansion provided by the type Ia supernovae (SNIa) Hubble diagram. However, the robustness of this evidence has been addressed recently with somewhat diverging conclusions. Aims: The purpose of this paper is to assess the robustness of the conclusion that the Universe is indeed accelerating if we rely only on low-redshift (z ≲ 2) observations, that is to say with SNIa, baryonic acoustic oscillations, measurements of the Hubble parameter at different redshifts, and measurements of the growth of matter perturbations. Methods: We used the standard statistical procedure of minimizing the χ2 function for the different probes to quantify the goodness of fit of a model for both ΛCDM and a simple nonaccelerated low-redshift power law model. In this analysis, we do not assume that supernovae intrinsic luminosity is independent of the redshift, which has been a fundamental assumption in most previous studies that cannot be tested. Results: We have found that, when SNIa intrinsic luminosity is not assumed to be redshift independent, a nonaccelerated low-redshift power law model is able to fit the low-redshift background data as well as, or even slightly better, than ΛCDM. When measurements of the growth of structures are added, a nonaccelerated low-redshift power law model still provides an excellent fit to the data for all the luminosity evolution models considered. Conclusions: Without the standard assumption that supernovae intrinsic luminosity is independent of the redshift, low-redshift probes are consistent with a nonaccelerated universe.

  6. Extending the accuracy of the SNAP interatomic potential form

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

    Wood, Mitchell A.; Thompson, Aidan P.

    The Spectral Neighbor Analysis Potential (SNAP) is a classical interatomic potential that expresses the energy of each atom as a linear function of selected bispectrum components of the neighbor atoms. An extension of the SNAP form is proposed that includes quadratic terms in the bispectrum components. The extension is shown to provide a large increase in accuracy relative to the linear form, while incurring only a modest increase in computational cost. The mathematical structure of the quadratic SNAP form is similar to the embedded atom method (EAM), with the SNAP bispectrum components serving as counterparts to the two-body density functionsmore » in EAM. It is also argued that the quadratic SNAP form is a special case of an artificial neural network (ANN). The effectiveness of the new form is demonstrated using an extensive set of training data for tantalum structures. Similarly to ANN potentials, the quadratic SNAP form requires substantially more training data in order to prevent overfitting, as measured by cross-validation analysis.« less

  7. Extending the accuracy of the SNAP interatomic potential form

    DOE PAGES

    Wood, Mitchell A.; Thompson, Aidan P.

    2018-03-28

    The Spectral Neighbor Analysis Potential (SNAP) is a classical interatomic potential that expresses the energy of each atom as a linear function of selected bispectrum components of the neighbor atoms. An extension of the SNAP form is proposed that includes quadratic terms in the bispectrum components. The extension is shown to provide a large increase in accuracy relative to the linear form, while incurring only a modest increase in computational cost. The mathematical structure of the quadratic SNAP form is similar to the embedded atom method (EAM), with the SNAP bispectrum components serving as counterparts to the two-body density functionsmore » in EAM. It is also argued that the quadratic SNAP form is a special case of an artificial neural network (ANN). The effectiveness of the new form is demonstrated using an extensive set of training data for tantalum structures. Similarly to ANN potentials, the quadratic SNAP form requires substantially more training data in order to prevent overfitting, as measured by cross-validation analysis.« less

  8. 2D electron density profile measurement in tokamak by laser-accelerated ion-beam probe.

    PubMed

    Chen, Y H; Yang, X Y; Lin, C; Wang, L; Xu, M; Wang, X G; Xiao, C J

    2014-11-01

    A new concept of Heavy Ion Beam Probe (HIBP) diagnostic has been proposed, of which the key is to replace the electrostatic accelerator of traditional HIBP by a laser-driven ion accelerator. Due to the large energy spread of ions, the laser-accelerated HIBP can measure the two-dimensional (2D) electron density profile of tokamak plasma. In a preliminary simulation, a 2D density profile was reconstructed with a spatial resolution of about 2 cm, and with the error below 15% in the core region. Diagnostics of 2D density fluctuation is also discussed.

  9. SNAP Assay Technology.

    PubMed

    O'Connor, Thomas P

    2015-12-01

    The most widely used immunoassay configuration is the enzyme-linked immunosorbent assay (ELISA) because the procedure produces highly sensitive and specific results and generally is easy to use. By definition, ELISAs are immunoassays used to detect a substance (typically an antigen or antibody) in which an enzyme is attached (conjugated) to one of the reactants and an enzymatic reaction is used to amplify the signal if the substance is present. Optimized ELISAs include several steps that are performed in sequence using a defined protocol that typically includes application of sample and an enzyme-conjugated antibody or antigen to an immobilized reagent, followed by wash and enzyme reaction steps. The SNAP assay is an in-clinic device that performs each of the ELISA steps in a timed sequential fashion with little consumer interface. The components and mechanical mechanism of the assay device are described. Detailed descriptions of features of the assay, which minimize nonspecific binding and enhance the ability to read results from weak-positive samples, are given. Basic principles used in assays with fundamentally different reaction mechanisms, namely, antigen-detection, antibody-detection, and competitive assays are given. Applications of ELISA technology, which led to the development of several multianalyte SNAP tests capable of testing for up to 6 analytes using a single-sample and a single-SNAP device are described. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

  10. Overview of SNAP

    EPA Pesticide Factsheets

    Section 612(c) of the Clean Air Act (CAA) requires the Agency to publish a list of acceptable and unacceptable substitutes for ozone-depleting substances (ODS). The SNAP program does not require that substitutes be risk- free to be found acceptable.

  11. Extending the accuracy of the SNAP interatomic potential form

    NASA Astrophysics Data System (ADS)

    Wood, Mitchell A.; Thompson, Aidan P.

    2018-06-01

    The Spectral Neighbor Analysis Potential (SNAP) is a classical interatomic potential that expresses the energy of each atom as a linear function of selected bispectrum components of the neighbor atoms. An extension of the SNAP form is proposed that includes quadratic terms in the bispectrum components. The extension is shown to provide a large increase in accuracy relative to the linear form, while incurring only a modest increase in computational cost. The mathematical structure of the quadratic SNAP form is similar to the embedded atom method (EAM), with the SNAP bispectrum components serving as counterparts to the two-body density functions in EAM. The effectiveness of the new form is demonstrated using an extensive set of training data for tantalum structures. Similar to artificial neural network potentials, the quadratic SNAP form requires substantially more training data in order to prevent overfitting. The quality of this new potential form is measured through a robust cross-validation analysis.

  12. Frequency-Domain Tomography for Single-shot, Ultrafast Imaging of Evolving Laser-Plasma Accelerators

    NASA Astrophysics Data System (ADS)

    Li, Zhengyan; Zgadzaj, Rafal; Wang, Xiaoming; Downer, Michael

    2011-10-01

    Intense laser pulses propagating through plasma create plasma wakefields that often evolve significantly, e.g. by expanding and contracting. However, such dynamics are known in detail only through intensive simulations. Laboratory visualization of evolving plasma wakes in the ``bubble'' regime is important for optimizing and scaling laser-plasma accelerators. Recently snap-shots of quasi-static wakes were recorded using frequency-domain holography (FDH). To visualize the wake's evolution, we have generalized FDH to frequency-domain tomography (FDT), which uses multiple probes propagating at different angles with respect to the pump pulse. Each probe records a phase streak, imprinting a partial record of the evolution of pump-created structures. We then topographically reconstruct the full evolution from all phase streaks. To prove the concept, a prototype experiment visualizing nonlinear index evolution in glass is demonstrated. Four probes propagating at 0, 0.6, 2, 14 degrees to the index ``bubble'' are angularly and temporally multiplexed to a single spectrometer to achieve cost-effective FDT. From these four phase streaks, an FDT algorithm analogous to conventional CT yields a single-shot movie of the pump's self-focusing dynamics.

  13. SNAP 10A FS-3 reactor performance

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

    Hawley, J.P.; Johnson, R.A.

    1966-08-15

    SNAP 10FS-3 was the first flight-qualified SNAP reactor system to be operated in a simulated space environment. Prestart-up qualification testing, automatic start-up, endurance period performance, extended operation test and reactor shutdown are described as they affected, or were affected by, overall reactor performance. Performance of the reactor control system and the diagnostic instrumentation is critically evaluted.

  14. A tissue snap-freezing apparatus without sacrificial cryogens

    NASA Astrophysics Data System (ADS)

    Vanapalli, Srinivas; Jagga, Sahil; Holland, Harry; ter Brake, Marcel

    2017-12-01

    Molecular technologies in cancer diagnosis require a fresh and frozen tissue, which is obtained by means of snap-freezing. Currently, coolants such as solid carbon dioxide and liquid nitrogen are used to preserve good morphology of the tissue. Using these coolants, snap freezing of tissues for diagnostic and research purposes is often time consuming, laborious, even hazardous and not user friendly. For that reason snap-freezing is not routinely applied at the location of biopsy acquisition. Furthermore, the influence of optimal cooling rate and cold sink temperature on the viability of the cells is not well known. In this paper, a snap-freezing apparatus powered by a small cryocooler is presented that will allow bio-medical research of tissue freezing methods and is safe to use in a hospital. To benchmark this apparatus, cooldown of a standard aluminum cryo-vial in liquid nitrogen is measured and the cooling rate is about -25 K/s between 295 K and 120 K. Sufficient cooling rate is obtained by a forced convective helium gas flow through a gap formed between the cryo-vial and a cold surface and is therefore chosen as the preferred cooling method. A conceptual design of the snap-apparatus with forced flow is discussed in this paper.

  15. In vivo evaluation of radiotracers targeting the melanin-concentrating hormone receptor 1: [11C]SNAP-7941 and [18F]FE@SNAP reveal specific uptake in the ventricular system.

    PubMed

    Zeilinger, Markus; Dumanic, Monika; Pichler, Florian; Budinsky, Lubos; Wadsak, Wolfgang; Pallitsch, Katharina; Spreitzer, Helmut; Lanzenberger, Rupert; Hacker, Marcus; Mitterhauser, Markus; Philippe, Cécile

    2017-08-14

    The MCHR1 is involved in the regulation of energy homeostasis and changes of the expression are linked to a variety of associated diseases, such as diabetes and adiposity. The study aimed at the in vitro and in vivo evaluation of [ 11 C]SNAP-7941 and [ 18 F]FE@SNAP as potential PET-tracers for the MCHR1. Competitive binding studies with non-radioactive derivatives and small-animal PET/CT and MRI brain studies were performed under baseline conditions and tracer displacement with the unlabelled MCHR1 antagonist (±)-SNAP-7941. Binding studies evinced high binding affinity of the non-radioactive derivatives. Small-animal imaging of [ 11 C]SNAP-7941 and [ 18 F]FE@SNAP evinced high tracer uptake in MCHR1-rich regions of the ventricular system. Quantitative analysis depicted a significant tracer reduction after displacement with (±)-SNAP-7941. Due to the high binding affinity of the non-labelled derivatives and the high specific tracer uptake of [ 11 C]SNAP-7941 and [ 18 F]FE@SNAP, there is strong evidence that both radiotracers may serve as highly suitable agents for specific MCHR1 imaging.

  16. A document review to characterize Atomic International SNAP fuels shipped to INEL 1966--1973

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

    Wahnschaffe, S.D.; Lords, R.E.; Kneff, D.W.

    1995-09-01

    This report provides the results of a document search and review study to obtain information on the spent fuels for the following six Nuclear Auxiliary Power (SNAP) reactor cores now stored at the Idaho National Engineering Laboratory (INEL): SNAP-2 Experimental Reactor, SNAP-2 Development Reactor, SNAP-10A Ground Test Reactor, SNAP-8 Experimental Reactor, SNAP-8 Development Reactor, and Shield Test Reactor. The report also covers documentation on SNAP fuel materials from four in-pile materials tests: NAA-82-1, NAA-115-2, NAA-117-1, and NAA-121. Pieces of these fuel materials are also stored at INEL as part of the SNAP fuel shipments.

  17. Creating Security System Models Using SNAP-PC.

    DTIC Science & Technology

    1987-05-01

    Submodel ATTGRD Prompts ............ 228 x ACKNOWLEDGEMENTS SNAP was originally developed in the late 1970’s by Pritsker & Associates, Inc., for Sandia...systems. The other was to simplify the simulation process so that a person knowledgeable in security planning and who had little experience in ...simulation techniques could use simulation in his evaluation of security systems. SNAP-PC was developed by Pritsker & Associates, Inc., for Sandia with

  18. Enantioselective Synthesis of SNAP-7941

    PubMed Central

    Goss, Jennifer M.; Schaus, Scott E.

    2009-01-01

    An enantioselective synthesis of SNAP-7941, a potent melanin concentrating hormone receptor antagonist, was achieved using two organocatalytic methods. The first method utilized to synthesize the enantioenriched dihydropyrimidone core was the Cinchona alkaloid-catalyzed Mannich reaction of β-keto esters to acyl imines and the second was chiral phosphoric acid-catalyzed Biginelli reaction. Completion of the synthesis was accomplished via selective urea formation at the N3 position of the dihydropyrimidone with the 3-(4-phenylpiperidin-1-yl)propyl amine side chain fragment. The synthesis of SNAP-7921 highlights the utility of asymmetric organocatalytic methods in the construction of an important class of chiral heterocycles. PMID:18767801

  19. Expression of the SNARE Protein SNAP-23 Is Essential for Cell Survival

    PubMed Central

    Kaul, Sunil; Mittal, Sharad K.; Feigenbaum, Lionel; Kruhlak, Michael J.; Roche, Paul A.

    2015-01-01

    Members of the SNARE-family of proteins are known to be key regulators of the membrane-membrane fusion events required for intracellular membrane traffic. The ubiquitously expressed SNARE protein SNAP-23 regulates a wide variety of exocytosis events and is essential for mouse development. Germline deletion of SNAP-23 results in early embryonic lethality in mice, and for this reason we now describe mice and cell lines in which SNAP-23 can be conditionally-deleted using Cre-lox technology. Deletion of SNAP-23 in CD19-Cre expressing mice prevents B lymphocyte development and deletion of SNAP-23 using a variety of T lymphocyte-specific Cre mice prevents T lymphocyte development. Acute depletion of SNAP-23 in mouse fibroblasts leads to rapid apoptotic cell death. These data highlight the importance of SNAP-23 for cell survival and describe a mouse in which specific cell types can be eliminated by expression of tissue-specific Cre-recombinase. PMID:25706117

  20. SNAP Employment and Training: Washington's Basic Food Employment & Training Program (BFET)

    ERIC Educational Resources Information Center

    Mohan, Lavanya

    2014-01-01

    SNAP Employment & Training (E&T) is an important component of SNAP (Supplemental Nutrition Assistance Program, formerly known as the Food Stamp Program) that supports a variety of education, training, employment, and related services for SNAP recipients. It gives recipients opportunities to gain skills, training, or experience that will…

  1. Black holes are neither particle accelerators nor dark matter probes.

    PubMed

    McWilliams, Sean T

    2013-01-04

    It has been suggested that maximally spinning black holes can serve as particle accelerators, reaching arbitrarily high center-of-mass energies. Despite several objections regarding the practical achievability of such high energies, and demonstrations past and present that such large energies could never reach a distant observer, interest in this problem has remained substantial. We show that, unfortunately, a maximally spinning black hole can never serve as a probe of high energy collisions, even in principle and despite the correctness of the original diverging energy calculation. Black holes can indeed facilitate dark matter annihilation, but the most energetic photons can carry little more than the rest energy of the dark matter particles to a distant observer, and those photons are actually generated relatively far from the black hole where relativistic effects are negligible. Therefore, any strong gravitational potential could probe dark matter equally well, and an appeal to black holes for facilitating such collisions is unnecessary.

  2. Fast simultaneous noncontrast angiography and intraplaque hemorrhage (fSNAP) sequence for carotid artery imaging.

    PubMed

    Chen, Shuo; Ning, Jia; Zhao, Xihai; Wang, Jinnan; Zhou, Zechen; Yuan, Chun; Chen, Huijun

    2017-02-01

    To propose a fast simultaneous noncontrast angiography and intraplaque hemorrhage (fSNAP) sequence for carotid artery imaging. The proposed fSNAP sequence uses a low-resolution reference acquisition for phase-sensitive reconstruction to speed up the scan, and an inversion recovery acquisition with arbitrary k-space filling order to generate similar contrast to conventional SNAP. Four healthy volunteers and eight patients were recruited to test the performance of fSNAP in vivo. The lumen area quantification, muscle-blood CNR, IPH-blood CNR, lumen SNR, and standard deviation and intraplaque hemorrhage (IPH) detection accuracy were compared between fSNAP and SNAP. By using a low-resolution reference acquisition with 1/4 matrix size of the full-resolution reference scan, the scan time of fSNAP was 37.5% less than that of SNAP. A high agreement of lumen area measurement (ICC = 0.97, 95% CI: 0.96-0.99) and IPH detection (Kappa = 1) were found between fSNAP and SNAP. Also, no significant difference was found for muscle-blood CNR (P = 0.25), IPH-blood CNR (P = 0.35), lumen SNR (P = 0.60), and standard deviation (P = 0.46) between the two techniques. The feasibility of fSNAP was validated. fSNAP can improve the imaging efficiency with similar performance to SNAP on carotid artery imaging. Magn Reson Med 77:753-758, 2017. © 2016 International Society for Magnetic Resonance in Medicine. © 2016 International Society for Magnetic Resonance in Medicine.

  3. Associations of cooking with dietary intake and obesity among SNAP participants

    PubMed Central

    Taillie, Lindsey Smith; Poti, Jennifer M.

    2017-01-01

    Introduction Participation in the Supplemental Nutrition Assistance Program (SNAP) may help ease economic and time constraints of cooking, helping low-income households prepare healthier meals. As a result, frequent cooking may be more strongly associated with improved dietary outcomes among SNAP recipients than among income-eligible non-SNAP-recipients. Alternately, increased frequency of home-cooked meals among SNAP participants may be beneficial simply by replacing fast food intake. The objective is to quantify the association between home cooking and fast food with diet intake and weight status among SNAP recipients. Methods 2015 data from low-income adults aged 19-65y from the National Health and Nutrition Survey, 2007-2010 (n=2,578) was used to examine associations between daily home-cooked dinner and weekly fast food intake with diet intake, including calories from solid fat and added sugar, key food groups (sugar-sweetened beverages (SSBs), fruit, and vegetables), and prevalence of overweight/obesity. Differences in these association for SNAP recipients vs. income-eligible non-recipients were analyzed, as well as whether associations were attenuated when controlling for fast food intake. Results Daily home-cooked dinners were associated with small improvements in dietary intake for SNAP recipients but not for non-recipients, including lower SSB intake (-54 kcal/day), and reduced prevalence of overweight/obesity (-6%) (p<0.05). However, these associations were attenuated after controlling for fast food intake. Consuming one fast food meal/week was associated with 9.3% and 11.6% higher overweight/obesity prevalence among SNAP recipients and non-recipients, respectively (p<0.05). Conclusion Strategies to improve dietary intake among SNAP recipients should consider both increasing home cooking and reducing fast food intake. PMID:28109417

  4. Territorial aggressiveness and predation: two possible origins of snapping in the ant Plectroctena minor.

    PubMed

    Dejean, Alain; Suzzoni, Jean-Pierre; Schatz, Bertrand; Orivel, Jérôme

    2002-07-01

    Plectroctena minor workers have long mandibles that can snap and deliver a sharp blow to intruders or prey, stunning or killing them. Encounters between homocolonial P. minor workers separated for 24 h or 15 days never resulted in snapping, while this behaviour was always noted during encounters between heterocolonial workers on neutral arenas or on the territory of a colony. In the latter case, only the aliens, that generally tried to escape, were snapped at. Snapping also occurred during encounters with workers belonging to sympatric ponerine species. During predation, the percentages of snapping varied according to prey nature, suggesting prey discrimination. Termite soldiers were always snapped at, while other prey were more often snapped close to rather than far from the nest entrances, indicating an intermingling of territorial aggressiveness and predatory behaviour. We discuss the adaptive value of snapping for hunting in galleries.

  5. Triggered Snap-Through of Bistable Shells

    NASA Astrophysics Data System (ADS)

    Cai, Yijie; Huang, Shicheng; Trase, Ian; Hu, Nan; Chen, Zi

    Elastic bistable shells are common structures in nature and engineering, such as the lobes of the Venus flytrap or the surface of a toy jumping poppers. Despite their ubiquity, the parameters that control the bistability of such structures are not well understood. In this study, we explore how the geometrical features of radially symmetric elastic shells affect the shape and potential energy of a shell's stable states, and how to tune certain parameters in order to generate a snap-through transition from a convex semi-stable state to concave stable state. We fabricated a series of elastic shells with varying geometric parameters out of silicone rubber and measured the resulting potential energy in the semi-stable state. Finite element simulations were also conducted in order to determine the deformation and stress in the shells during snap-through. It was found that the energy of the semi-stable state is controlled by only two geometric parameters and a dimensionless ratio. We also noted two distinct transitions during snap-through, one between monostability and semi-bistability (the state a popper toy is in before it snaps-through and jumps), and a second transition between semi-bistability and true bistability. This work shows that it is possible to use a set of simple parameters to tailor the energy landscape of an elastic shell in order to generate complex trigger motions for their potential use in smart applications. Z.C. acknowledge support from Society in Science-Branco Weiss Fellowship, administered by ETH Zurich.

  6. Phosphorylation of SNAP-23 regulates its dynamic membrane association during mast cell exocytosis

    PubMed Central

    Naskar, Pieu

    2017-01-01

    ABSTRACT Upon allergen challenge, mast cells (MCs) respond by releasing pre-stored mediators from their secretory granules by the transient mechanism of porosome-mediated cell secretion. The target SNARE SNAP-23 has been shown to be important for MC exocytosis, and our previous studies revealed the presence of one basal (Thr102) and two induced (Ser95 and Ser120) phosphorylation sites in its linker region. To study the role of SNAP-23 phosphorylation in the regulation of exocytosis, green fluorescence protein-tagged wild-type SNAP-23 (GFP-SNAP-23) and its phosphorylation mutants were transfected into rat basophilic leukemia (RBL-2H3) MCs. Studies on GFP-SNAP-23 transfected MCs revealed some dynamic changes in SNAP-23 membrane association. SNAP-23 was associated with plasma membrane in resting MCs, however, on activation a portion of it translocated to cytosol and internal membranes. These internal locations were secretory granule membranes. This dynamic change in the membrane association of SNAP-23 in MCs may be important for mediating internal granule-granule fusions in compound exocytosis. Further studies with SNAP-23 phosphorylation mutants revealed an important role for the phosphorylation at Thr102 in its initial membrane association, and of induced phosphorylation at Ser95 and Ser120 in its internal membrane association, during MC exocytosis. PMID:28784843

  7. Phosphorylation of SNAP-23 regulates its dynamic membrane association during mast cell exocytosis.

    PubMed

    Naskar, Pieu; Puri, Niti

    2017-09-15

    Upon allergen challenge, mast cells (MCs) respond by releasing pre-stored mediators from their secretory granules by the transient mechanism of porosome-mediated cell secretion. The target SNARE SNAP-23 has been shown to be important for MC exocytosis, and our previous studies revealed the presence of one basal (Thr 102 ) and two induced (Ser 95 and Ser 120 ) phosphorylation sites in its linker region. To study the role of SNAP-23 phosphorylation in the regulation of exocytosis, green fluorescence protein-tagged wild-type SNAP-23 (GFP-SNAP-23) and its phosphorylation mutants were transfected into rat basophilic leukemia (RBL-2H3) MCs. Studies on GFP-SNAP-23 transfected MCs revealed some dynamic changes in SNAP-23 membrane association. SNAP-23 was associated with plasma membrane in resting MCs, however, on activation a portion of it translocated to cytosol and internal membranes. These internal locations were secretory granule membranes. This dynamic change in the membrane association of SNAP-23 in MCs may be important for mediating internal granule-granule fusions in compound exocytosis. Further studies with SNAP-23 phosphorylation mutants revealed an important role for the phosphorylation at Thr 102 in its initial membrane association, and of induced phosphorylation at Ser 95 and Ser 120 in its internal membrane association, during MC exocytosis. © 2017. Published by The Company of Biologists Ltd.

  8. Botulinum neurotoxin type A: Actions beyond SNAP-25?

    PubMed

    Matak, Ivica; Lacković, Zdravko

    2015-09-01

    Botulinum neurotoxin type A (BoNT/A), the most potent toxin known in nature which causes botulism, is a commonly used therapeutic protein. It prevents synaptic vesicle neuroexocytosis by proteolytic cleavage of synaptosomal-associated protein of 25 kDa (SNAP-25). It is widely believed that BoNT/A therapeutic or toxic actions are exclusively mediated by SNAP-25 cleavage. On the other hand, in vitro and in vivo findings suggest that several BoNT/A actions related to neuroexocytosis, cell cycle and apoptosis, neuritogenesis and gene expression are not necessarily mediated by this widely accepted mechanism of action. In present review we summarize the literature evidence which point to the existence of unknown BoNT/A molecular target(s) and modulation of unknown signaling pathways. The effects of BoNT/A apparently independent of SNAP-25 occur at similar doses/concentrations known to induce SNAP-25 cleavage and prevention of neurotransmitter release. Accordingly, these effects might be pharmacologically significant. Potentially the most interesting are observations of antimitotic and antitumor activity of BoNT/A. However, the exact mechanisms require further studies. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  9. The Classroom Animal: Snapping Turtles.

    ERIC Educational Resources Information Center

    Kramer, David C.

    1987-01-01

    Describes the distinctive features of the common snapping turtle. Discusses facts and misconceptions held about the turtle. Provides guidelines for proper care and treatment of a young snapper in a classroom environment. (ML)

  10. A VESICLE TRAFFICKING PROTEIN αSNAP REGULATES PANETH CELL DIFFERENTIATION IN VIVO

    PubMed Central

    Lechuga, Susana; Naydenov, Nayden G.; Feygin, Alex; Jimenez, Antonio J.; Ivanov, Andrei I.

    2017-01-01

    A soluble N-ethylmaleimide-sensitive factor-attachment protein alpha (αSNAP) is a multifunctional scaffolding protein that regulates intracellular vesicle trafficking and signaling. In cultured intestinal epithelial cells, αSNAP has been shown to be essential for cell survival, motility, and adhesion; however, its physiologic functions in the intestinal mucosa remain unknown. In the present study, we used a mouse with a spontaneous hydrocephalus with hop gait (hyh) mutation of αSNAP to examine the roles of this trafficking protein in regulating intestinal epithelial homeostasis in vivo. Homozygous hyh mice demonstrated decreased expression of αSNAP protein in the intestinal epithelium, but did not display gross abnormalities of epithelial architecture in the colon and ileum. Such αSNAP depletion attenuated differentiation of small intestinal epithelial enteroids ex vivo. Furthermore, αSNAP-deficient mutant animals displayed reduced formation of lysozyme granules in small intestinal crypts and decreased expression of lysozyme and defensins in the intestinal mucosa, which is indicative of defects in Paneth cell differentiation. By contrast, development of Goblet cells, enteroendocrine cells, and assembly of enterocyte apical junctions was not altered in hyh mutant mice. Our data revealed a novel role of αSNAP in the intestinal Paneth cell differentiation in vivo. PMID:28359759

  11. Snap-in of particles at curved liquid interfaces

    NASA Astrophysics Data System (ADS)

    Li, Chao; Moradiafrapoli, Momene; Marston, Jeremy

    2016-11-01

    The contact of particles with liquid interfaces constitutes the first stage in the formation of a particle-laden interface, the so-called "snap-in effect". Here, we report on an experimental study using high-speed video to directly visualize the snap-in process and the approach to the equilibrium state of a particle at a curved liquid interface (i.e. droplet surface). We image the evolution of the contact line, which is found to follow a power-law scaling in time, and the dynamic contact angle during the snap-in. Both hydrophilic and hydrophobic particles are explored and we match the lift-off stage of the particles with a simple force balance. We also explore some multi-particle experiments, eluding to the dynamics of particle-laden interface formation.

  12. Snap-through twinkling energy generation through frequency up-conversion

    NASA Astrophysics Data System (ADS)

    Panigrahi, Smruti R.; Bernard, Brian P.; Feeny, Brian F.; Mann, Brian P.; Diaz, Alejandro R.

    2017-07-01

    A novel experimental energy harvester is investigated for its energy harvesting capability by frequency up-conversion using snap-through structures. In particular, a single-degree-of-freedom (SDOF) experimental energy harvester model is built using a snap-through nonlinear element. The snap-through dynamics is facilitated by the experimental setup of a twinkling energy generator (TEG) consisting of linear springs and attracting cylindrical bar magnets. A cylindrical coil of enamel-coated magnet wire is used as the energy generator. The governing equations are formulated mathematically and solved numerically for a direct comparison with the experimental results. The experimental TEG and the numerical simulation results show 25-fold frequency up-conversion and the power harvesting capacity of the SDOF TEG.

  13. 76 FR 27603 - Supplemental Nutrition Assistance Program: Civil Rights Protections for SNAP Households

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-12

    ...,'' to identify and address any major civil rights impacts the rule might have on minorities, women, and... Nutrition Assistance Program: Civil Rights Protections for SNAP Households AGENCY: Food and Nutrition... Nutrition Assistance Program (SNAP) regulations that secure civil rights protections for SNAP households and...

  14. Fluorescent Labeling of COS-7 Expressing SNAP-tag Fusion Proteins for Live Cell Imaging

    PubMed Central

    Provost, Christopher R.; Sun, Luo

    2010-01-01

    SNAP-tag and CLIP-tag protein labeling systems enable the specific, covalent attachment of molecules, including fluorescent dyes, to a protein of interest in live cells. These systems offer a broad selection of fluorescent substrates optimized for a range of imaging instrumentation. Once cloned and expressed, the tagged protein can be used with a variety of substrates for numerous downstream applications without having to clone again. There are two steps to using this system: cloning and expression of the protein of interest as a SNAP-tag fusion, and labeling of the fusion with the SNAP-tag substrate of choice. The SNAP-tag is a small protein based on human O6-alkylguanine-DNA-alkyltransferase (hAGT), a DNA repair protein. SNAP-tag labels are dyes conjugated to guanine or chloropyrimidine leaving groups via a benzyl linker. In the labeling reaction, the substituted benzyl group of the substrate is covalently attached to the SNAP-tag. CLIP-tag is a modified version of SNAP-tag, engineered to react with benzylcytosine rather than benzylguanine derivatives. When used in conjunction with SNAP-tag, CLIP-tag enables the orthogonal and complementary labeling of two proteins simultaneously in the same cells. PMID:20485262

  15. Cutaneous fibroma in a captive common snapping turtle (Chelydra serpentina).

    PubMed

    Gonzales-Viera, O; Bauer, G; Bauer, A; Aguiar, L S; Brito, L T; Catão-Dias, J L

    2012-11-01

    An adult female common snapping turtle (Chelydra serpentina) had a mass on the plantar surface of the right forelimb that was removed surgically. Microscopical examination revealed many spindle cells with mild anisocytosis and anisokaryosis and a surrounding collagenous stroma. There were no mitoses. Immunohistochemistry showed that the spindle cells expressed vimentin, but not desmin. A diagnosis of cutaneous fibroma was made. Tumours are reported uncommonly in chelonian species. Cutaneous fibroma has been diagnosed in an alligator snapping turtle (Macrochelys temminckii), but not previously in a common snapping turtle. Crown Copyright © 2012. Published by Elsevier Ltd. All rights reserved.

  16. 78 FR 11967 - Supplemental Nutrition Assistance Program (SNAP): Updated Trafficking Definition and Supplemental...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-21

    ... disqualification of a SNAP client who intentionally obtains cash by purchasing, with SNAP benefits, products that... exchange for cash refund of deposit(s); or who intentionally resells or exchanges products purchased with... the SNAP client. Examples of the latter would be the purchase, by retailers, of products originally...

  17. Gasket and snap ring installation tool

    DOEpatents

    Southerland, Jr., James M.; Barringer, Jr., Curtis N.

    1994-01-01

    A tool for installing a gasket and a snap ring including a shaft, a first plate attached to the forward end of the shaft, a second plate slidably carried by the shaft, a spring disposed about the shaft between the first and second plates, and a sleeve that is free to slide over the shaft and engage the second plate. The first plate has a loading surface with a loading groove for receiving a snap ring and a shoulder for holding a gasket. A plurality of openings are formed through the first plate, communicating with the loading groove and approximately equally spaced about the groove. A plurality of rods are attached to the second plate, each rod slidable in one of the openings. In use, the loaded tool is inserted into a hollow pipe or pipe fitting having an internal flange and an internal seating groove, such that the gasket is positioned against the flange and the ring is in the approximate plane of the seating groove. The sleeve is pushed against the second plate, sliding the second plate towards the first plate, compressing the spring and sliding the rods forwards in the openings. The rods engage the snap ring and urge the ring from the loading groove into the seating groove.

  18. Impact and ethics of excluding sweetened beverages from the SNAP program.

    PubMed

    Barnhill, Anne

    2011-11-01

    The state of New York recently petitioned the US Department of Agriculture (USDA) for permission to conduct a demonstration project in which sweetened beverages would be excluded from the foods eligible to be purchased with Supplemental Assistance Nutrition Program (SNAP) benefits (i.e., food stamps) in New York City. The USDA and advocacy groups have raised objections to new SNAP restrictions such as the proposed exclusion of sweetened beverages. Some objections rest on empirical issues best resolved by demonstration projects or pilot studies of new exclusions. Other objections question the equity of excluding sweetened beverages from SNAP; these objections are important but not ethically decisive. The USDA should approve the proposed demonstration project and should encourage other pilot studies to assess the effects of excluding sweetened beverages from SNAP.

  19. Impact and Ethics of Excluding Sweetened Beverages From the SNAP Program

    PubMed Central

    2011-01-01

    The state of New York recently petitioned the US Department of Agriculture (USDA) for permission to conduct a demonstration project in which sweetened beverages would be excluded from the foods eligible to be purchased with Supplemental Assistance Nutrition Program (SNAP) benefits (i.e., food stamps) in New York City. The USDA and advocacy groups have raised objections to new SNAP restrictions such as the proposed exclusion of sweetened beverages. Some objections rest on empirical issues best resolved by demonstration projects or pilot studies of new exclusions. Other objections question the equity of excluding sweetened beverages from SNAP; these objections are important but not ethically decisive. The USDA should approve the proposed demonstration project and should encourage other pilot studies to assess the effects of excluding sweetened beverages from SNAP. PMID:21566025

  20. SNAP-25 in hippocampal CA3 region is required for long-term memory formation

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

    Hou Qiuling; Gao Xiang; Lu Qi

    SNAP-25 is a synaptosomal protein of 25 kDa, a key component of synaptic vesicle-docking/fusion machinery, and plays a critical role in exocytosis and neurotransmitter release. We previously reported that SNAP-25 in the hippocampal CA1 region is involved in consolidation of contextual fear memory and water-maze spatial memory (Hou et al. European J Neuroscience, 20: 1593-1603, 2004). SNAP-25 is expressed not only in the CA1 region, but also in the CA3 region, and the SNAP-25 mRNA level in the CA3 region is higher than in the CA1 region. Here, we provide evidence that SNAP-25 in the CA3 region is also involvedmore » in learning/memory. Intra-CA3 infusion of SNAP-25 antisense oligonucleotide impaired both long-term contextual fear memory and water-maze spatial memory, with short-term memory intact. Furthermore, the SNAP-25 antisense oligonucleotide suppressed the long-term potentiation (LTP) of field excitatory post-synaptic potential (fEPSP) in the mossy-fiber pathway (DG-CA3 pathway), with no effect on paired-pulse facilitation of the fEPSP. These results are consistent with the notion that SNAP-25 in the hippocampal CA3 region is required for long-term memory formation.« less

  1. Ending SNAP subsidies for sugar-sweetened beverages could reduce obesity and type 2 diabetes.

    PubMed

    Basu, Sanjay; Seligman, Hilary Kessler; Gardner, Christopher; Bhattacharya, Jay

    2014-06-01

    To reduce obesity and type 2 diabetes rates, lawmakers have proposed modifying Supplemental Nutrition Assistance Program (SNAP) benefits to encourage healthier food choices. We examined the impact of two proposed policies: a ban on using SNAP dollars to buy sugar-sweetened beverages; and a subsidy in which for every SNAP dollar spent on fruit and vegetables, thirty cents is credited back to participants' SNAP benefit cards. We used nationally representative data and models describing obesity, type 2 diabetes, and determinants of food consumption among a sample of over 19,000 SNAP participants. We found that a ban on SNAP purchases of sugar-sweetened beverages would be expected to significantly reduce obesity prevalence and type 2 diabetes incidence, particularly among adults ages 18-65 and some racial and ethnic minorities. The subsidy policy would not be expected to have a significant effect on obesity and type 2 diabetes, given available data. Such a subsidy could, however, more than double the proportion of SNAP participants who meet federal vegetable and fruit consumption guidelines. Project HOPE—The People-to-People Health Foundation, Inc.

  2. A vesicle trafficking protein αSNAP regulates Paneth cell differentiation in vivo.

    PubMed

    Lechuga, Susana; Naydenov, Nayden G; Feygin, Alex; Jimenez, Antonio J; Ivanov, Andrei I

    2017-05-13

    A soluble N-ethylmaleimide-sensitive factor-attachment protein alpha (αSNAP) is a multifunctional scaffolding protein that regulates intracellular vesicle trafficking and signaling. In cultured intestinal epithelial cells, αSNAP has been shown to be essential for cell survival, motility, and adhesion; however, its physiologic functions in the intestinal mucosa remain unknown. In the present study, we used a mouse with a spontaneous hydrocephalus with hop gait (hyh) mutation of αSNAP to examine the roles of this trafficking protein in regulating intestinal epithelial homeostasis in vivo. Homozygous hyh mice demonstrated decreased expression of αSNAP protein in the intestinal epithelium, but did not display gross abnormalities of epithelial architecture in the colon and ileum. Such αSNAP depletion attenuated differentiation of small intestinal epithelial enteroids ex vivo. Furthermore, αSNAP-deficient mutant animals displayed reduced formation of lysozyme granules in small intestinal crypts and decreased expression of lysozyme and defensins in the intestinal mucosa, which is indicative of defects in Paneth cell differentiation. By contrast, development of Goblet cells, enteroendocrine cells, and assembly of enterocyte apical junctions was not altered in hyh mutant mice. Our data revealed a novel role of αSNAP in the intestinal Paneth cell differentiation in vivo. Copyright © 2017 Elsevier Inc. All rights reserved.

  3. Study of plasma parameters in a pulsed plasma accelerator using triple Langmuir probe

    NASA Astrophysics Data System (ADS)

    Borthakur, S.; Talukdar, N.; Neog, N. K.; Borthakur, T. K.

    2018-01-01

    A Triple Langmuir Probe (TLP) has been used to study plasma parameters of a transient plasma produced in a newly developed Pulsed Plasma Accelerator system. In this experiment, a TLP with a capacitor based current mode biasing circuit was used that instantaneously gives voltage traces in an oscilloscope which are directly proportional to the plasma electron temperature and density. The electron temperature (Te) and plasma density (ne) of the plasma are measured with the help of this probe and found to be 24.13 eV and 3.34 × 1021/m3 at the maximum energy (-15 kV) of the system, respectively. An attempt was also made to analyse the time-dependent fluctuations in plasma parameters detected by the highly sensitive triple probe. In addition to this, the variation of these parameters under different discharge voltages was studied. The information obtained from these parameters is the initial diagnostics of a new device which is to be dedicated to study the impact of high heat flux plasma stream upon material surfaces inside an ITER like tokamak.

  4. Common snapping turtle preys on an adult western grebe

    USGS Publications Warehouse

    Igl, L.D.; Peterson, S.L.

    2010-01-01

    The identification of predators of aquatic birds can be difficult. The Common Snapping Turtle (Chelydra serpentine) is considered a major predator of waterfowl and other aquatic birds, but the evidence for this reputation is based largely on circumstantial or indirect evidence rather than direct observations. Herein, the first documented observations of a snapping turtle attacking and killing an adult Western Grebe (Aechmophorus occidentalis) are described.

  5. Taking Lessons Learned from a Proxy Application to a Full Application for SNAP and PARTISN

    DOE PAGES

    Womeldorff, Geoffrey Alan; Payne, Joshua Estes; Bergen, Benjamin Karl

    2017-06-09

    SNAP is a proxy application which simulates the computational motion of a neutral particle transport code, PARTISN. Here in this work, we have adapted parts of SNAP separately; we have re-implemented the iterative shell of SNAP in the task-model runtime Legion, showing an improvement to the original schedule, and we have created multiple Kokkos implementations of the computational kernel of SNAP, displaying similar performance to the native Fortran. We then translate our Kokkos experiments in SNAP to PARTISN, necessitating engineering development, regression testing, and further thought.

  6. Taking Lessons Learned from a Proxy Application to a Full Application for SNAP and PARTISN

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

    Womeldorff, Geoffrey Alan; Payne, Joshua Estes; Bergen, Benjamin Karl

    SNAP is a proxy application which simulates the computational motion of a neutral particle transport code, PARTISN. Here in this work, we have adapted parts of SNAP separately; we have re-implemented the iterative shell of SNAP in the task-model runtime Legion, showing an improvement to the original schedule, and we have created multiple Kokkos implementations of the computational kernel of SNAP, displaying similar performance to the native Fortran. We then translate our Kokkos experiments in SNAP to PARTISN, necessitating engineering development, regression testing, and further thought.

  7. Snapping shrimp sound production patterns on Caribbean coral reefs: relationships with celestial cycles and environmental variables

    NASA Astrophysics Data System (ADS)

    Lillis, Ashlee; Mooney, T. Aran

    2018-06-01

    The rich acoustic environment of coral reefs, including the sounds of a variety of fish and invertebrates, is a reflection of the structural complexity and biological diversity of these habitats. Emerging interest in applying passive acoustic monitoring and soundscape analysis to measure coral reef habitat characteristics and track ecological patterns is hindered by a poor understanding of the most common and abundant sound producers on reefs—the snapping shrimp. Here, we sought to address several basic biophysical drivers of reef sound by investigating acoustic activity patterns of snapping shrimp populations on two adjacent coral reefs using a detailed snap detection analysis routine to a high-resolution 2.5-month acoustic dataset from the US Virgin Islands. The reefs exhibited strong diel and lunar periodicity in snap rates and clear spatial differences in snapping levels. Snap rates peaked at dawn and dusk and were higher overall during daytime versus nighttime, a seldom-reported pattern in earlier descriptions of diel snapping shrimp acoustic activity. Small differences between the sites in snap rate rhythms were detected and illustrate how analyses of specific soundscape elements might reveal subtle between-reef variation. Snap rates were highly correlated with environmental variables, including water temperature and light, and were found to be sensitive to changes in oceanographic forcing. This study further establishes snapping shrimp as key players in the coral reef chorus and provides evidence that their acoustic output reflects a combination of environmental conditions, celestial influences, and spatial habitat variation. Effective application of passive acoustic monitoring in coral reef habitats using snap rates or snapping-influenced acoustic metrics will require a mechanistic understanding of the underlying spatial and temporal variation in snapping shrimp sound production across multiple scales.

  8. Alpha-SNAP functions in insulin exocytosis from mature, but not immature secretory granules in pancreatic beta cells.

    PubMed

    Nakamichi, Y; Nagamatsu, S

    1999-06-24

    To explore alpha-SNAP function in insulin exocytosis from either immature or mature secretory granules in pancreatic beta cells, we studied the effects of overexpression of adenovirus-mediated wild-type alpha-SNAP and C-terminally deleted alpha-SNAP mutant (1-285) on newly synthesized proinsulin and insulin release by rat islets and MIN6 cells. Rat islets overexpressing alpha-SNAP and mutant alpha-SNAP were pulse-chased. Exocytosis from immature and mature insulin secretory granules was measured as fractional (%) labeled-proinsulin release immediately after the pulse-labeling and percentage labeled-insulin release after a 3-h chase period, respectively. There was no difference in percentage labeled-proinsulin release between the control and alpha-SNAP or mutant alpha-SNAP-overexpressed islets. Although percentage labeled-insulin release after a 3-h chase period was significantly increased in alpha-SNAP-overexpressed islets, it was decreased in mutant alpha-SNAP-overexpressed islets. Thus, the results demonstrated that alpha-SNAP overexpression in rat islets primarily increased exocytosis from mature, but not immature insulin secretory granules. On the other hand, in MIN6 cells, alpha-SNAP overexpression scarcely affected glucose-stimulated insulin release; therefore, we examined the effect of mutant alpha-SNAP overexpression as the dominant-negative inhibitor on the newly synthesized proinsulin/insulin release using the same protocol as in the rat islet experiments. alpha-SNAP mutant (1-285) overexpression in MIN6 cells decreased the percentage labeled insulin release from mature secretory granules, but not percentage labeled proinsulin release from immature secretory granules. Thus, our data demonstrate that alpha-SNAP functions mainly in the mature insulin secretory granules in pancreatic beta cells. Copyright 1999 Academic Press.

  9. NIP-SNAP-1 and -2 mitochondrial proteins are maintained by heat shock protein 60.

    PubMed

    Yamamoto, Soh; Okamoto, Tomoya; Ogasawara, Noriko; Hashimoto, Shin; Shiraishi, Tsukasa; Sato, Toyotaka; Yamamoto, Keisuke; Tsutsumi, Hiroyuki; Takano, Kenichi; Himi, Testuo; Itoh, Hideaki; Yokota, Shin-Ichi

    2017-02-12

    NIP-SNAP-1 and -2 are ubiquitous proteins thought to be associated with maintenance of mitochondrial function, neuronal transmission, and autophagy. However, their physiological functions remain largely unknown. To elucidate their functional importance, we screened for proteins that interact with NIP-SNAP-1 and -2, resulting in identification of HSP60 and P62/SQSTM1 as binding proteins. NIP-SNAP-1 and -2 localized in the mitochondrial inner membrane space, whereas HSP60 localized in the matrix. Native gel electrophoresis and filter trap assays revealed that human HSP60 prevented aggregation of newly synthesized NIP-SNAP-2 in an in vitro translation system. Moreover, expression levels of NIP-SNAP-1 and -2 in cells were decreased by knockdown of HSP60, but not HSP10. These findings indicate that HSP60 promotes folding and maintains the stability of NIP-SNAP-1 and -2. Copyright © 2016 Elsevier Inc. All rights reserved.

  10. SnapShot: The Bacterial Cytoskeleton.

    PubMed

    Fink, Gero; Szewczak-Harris, Andrzej; Löwe, Jan

    2016-07-14

    Most bacteria and archaea contain filamentous proteins and filament systems that are collectively known as the bacterial cytoskeleton, though not all of them are cytoskeletal, affect cell shape, or maintain intracellular organization. To view this SnapShot, open or download the PDF. Copyright © 2016. Published by Elsevier Inc.

  11. Developmentally regulated switch in alternatively spliced SNAP-25 isoforms alters facilitation of synaptic transmission.

    PubMed

    Bark, Christina; Bellinger, Frederick P; Kaushal, Ashutosh; Mathews, James R; Partridge, L Donald; Wilson, Michael C

    2004-10-06

    Although the basic molecular components that promote regulated neurotransmitter release are well established, the contribution of these proteins as regulators of the plasticity of neurotransmission and refinement of synaptic connectivity during development is elaborated less fully. For example, during the period of synaptic growth and maturation in brain, the expression of synaptosomal protein 25 kDa (SNAP-25), a neuronal t-SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptor) essential for action potential-dependent neuroexocytosis, is altered through alternative splicing of pre-mRNA transcripts. We addressed the role of the two splice-variant isoforms of SNAP-25 with a targeted mouse mutation that impairs the shift from SNAP-25a to SNAP-25b. Most of these mutant mice die between 3 and 5 weeks of age, which coincides with the time when SNAP-25b expression normally reaches mature levels in brain and synapse formation is essentially completed. The altered expression of these SNAP-25 isoforms influences short-term synaptic function by affecting facilitation but not the initial probability of release. This suggests that mechanisms controlling alternative splicing between SNAP-25 isoforms contribute to a molecular switch important for survival that helps to guide the transition from immature to mature synaptic connections, as well as synapse regrowth and remodeling after neural injury.

  12. α-SNAP regulates dynamic, on-site assembly and calcium selectivity of Orai1 channels.

    PubMed

    Li, Peiyao; Miao, Yong; Dani, Adish; Vig, Monika

    2016-08-15

    Orai1 forms a highly calcium-selective pore of the calcium release activated channel, and α-SNAP is necessary for its function. Here we show that α-SNAP regulates on-site assembly of Orai1 dimers into calcium-selective multimers. We find that Orai1 is a dimer in resting primary mouse embryonic fibroblasts but displays variable stoichiometry in the plasma membrane of store-depleted cells. Remarkably, α-SNAP depletion induces formation of higher-order Orai1 oligomers, which permeate significant levels of sodium via Orai1 channels. Sodium permeation in α-SNAP-deficient cells cannot be corrected by tethering multiple Stim1 domains to Orai1 C-terminal tail, demonstrating that α-SNAP regulates functional assembly and calcium selectivity of Orai1 multimers independently of Stim1 levels. Fluorescence nanoscopy reveals sustained coassociation of α-SNAP with Stim1 and Orai1, and α-SNAP-depleted cells show faster and less constrained mobility of Orai1 within ER-PM junctions, suggesting Orai1 and Stim1 coentrapment without stable contacts. Furthermore, α-SNAP depletion significantly reduces fluorescence resonance energy transfer between Stim1 and Orai1 N-terminus but not C-terminus. Taken together, these data reveal a unique role of α-SNAP in the on-site functional assembly of Orai1 subunits and suggest that this process may, in part, involve enabling crucial low-affinity interactions between Orai1 N-terminus and Stim1. © 2016 Li, Miao, et al. This article is distributed by The American Society for Cell Biology under license from the author(s). Two months after publication it is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License (http://creativecommons.org/licenses/by-nc-sa/3.0).

  13. Telling our stories: heroin-assisted treatment and SNAP activism in the Downtown Eastside of Vancouver.

    PubMed

    Boyd, Susan; Murray, Dave; MacPherson, Donald

    2017-05-18

    This article highlights the experiences of a peer-run group, SALOME/NAOMI Association of Patients (SNAP), that meets weekly in the Downtown Eastside of Vancouver, British Columbia, Canada. SNAP is a unique independent peer- run drug user group that formed in 2011 following Canada's first heroin-assisted treatment trial (HAT), North America Opiate Medication Initiative (NAOMI). SNAP's members are now made up of former research participants who participated in two heroin-assisted trials in Vancouver. This article highlights SNAP members' experiences as research subjects in Canada's second clinical trial conducted in Vancouver, Study to Assess Longer-term Opioid Medication Effectiveness (SALOME), that began recruitment of research participants in 2011. This paper draws on one brainstorming session, three focus groups, and field notes, with the SALOME/NAOMI Association of Patients (SNAP) in late 2013 about their experiences as research subjects in Canada's second clinical trial, SALOME in the DTES of Vancouver, and fieldwork from a 6-year period (March 2011 to February 2017) with SNAP members. SNAP's research draws on research principles developed by drug user groups and critical methodological frameworks on community-based research for social justice. The results illuminate how participating in the SALOME clinical trial impacted the lives of SNAP members. In addition, the findings reveal how SNAP member's advocacy for HAT impacts the group in positive ways. Seven major themes emerged from the analysis of the brainstorming and focus groups: life prior to SALOME, the clinic setting and routine, stability, 6-month transition, support, exiting the trial and ethics, and collective action, including their participation in a constitutional challenge in the Supreme Court of BC to continue receiving HAT once the SALOME trial ended. HAT benefits SNAP members. They argue that permanent HAT programs should be established in Canada because they are an effective harm reduction

  14. Probing plasma wakefields using electron bunches generated from a laser wakefield accelerator

    NASA Astrophysics Data System (ADS)

    Zhang, C. J.; Wan, Y.; Guo, B.; Hua, J. F.; Pai, C.-H.; Li, F.; Zhang, J.; Ma, Y.; Wu, Y. P.; Xu, X. L.; Mori, W. B.; Chu, H.-H.; Wang, J.; Lu, W.; Joshi, C.

    2018-04-01

    We show experimental results of probing the electric field structure of plasma wakes by using femtosecond relativistic electron bunches generated from a laser wakefield accelerator. Snapshots of laser-driven linear wakes in plasmas with different densities and density gradients are captured. The spatiotemporal evolution of the wake in a plasma density up-ramp is recorded. Two parallel wakes driven by a laser with a main spot and sidelobes are identified in the experiment and reproduced in simulations. The capability of this new method for capturing the electron- and positron-driven wakes is also shown via 3D particle-in-cell simulations.

  15. Suprathermal and Solar Energetic Particles - Key questions for the Interstellar Mapping and Acceleration Probe (IMAP)

    NASA Astrophysics Data System (ADS)

    Desai, M. I.; McComas, D. J.; Christian, E. R.; Mewaldt, R. A.; Schwadron, N.

    2014-12-01

    Solar energetic particles or SEPs from suprathermal (few keV) up to relativistic (~few GeV) speeds are accelerated near the Sun in at least two ways, namely, (1) by magnetic reconnection-driven processes during solar flares resulting in impulsive SEPs and (2) at fast coronal-mass-ejection-driven shock waves that produce large gradual SEP events. Large gradual SEP events are of particular interest because the accompanying high-energy (>10s MeV) protons pose serious radiation threats to human explorers living and working outside low-Earth orbit and to technological assets such as communications and scientific satellites in space. However, a complete understanding of SEP events has eluded us primarily because their properties, as observed near Earth orbit, are smeared due to mixing and contributions from many important physical effects. Thus, despite being studied for decades, several key questions regarding SEP events remain unanswered. These include (1) What are the contributions of co-temporal flares, jets, and CME shocks to impulsive and gradual SEP events?; (2) Do flares contribute to large SEP events directly by providing high-energy particles and/or by providing the suprathermal seed population?; (3) What are the roles of ambient turbulence/waves and self-generated waves?; (4) What are the origins of the source populations and how do their temporal and spatial variations affect SEP properties?; and (5) How do diffusion and scattering during acceleration and propagation through the interplanetary medium affect SEP properties observed out in the heliosphere? This talk describes how during the next decade, inner heliospheric measurements from the Solar Probe Plus and Solar Orbiter in conjunction with high sensitivity measurements from the Interstellar Mapping and Acceleration Probe will provide the ground-truth for various models of particle acceleration and transport and address these questions.

  16. Vortex formation with a snapping shrimp claw.

    PubMed

    Hess, David; Brücker, Christoph; Hegner, Franziska; Balmert, Alexander; Bleckmann, Horst

    2013-01-01

    Snapping shrimp use one oversized claw to generate a cavitating high speed water jet for hunting, defence and communication. This work is an experimental investigation about the jet generation. Snapping shrimp (Alpheus-bellulus) were investigated by using an enlarged transparent model reproducing the closure of the snapper claw. Flow inside the model was studied using both High-Speed Particle Image Velocimetry (HS-PIV) and flow visualization. During claw closure a channel-like cavity was formed between the plunger and the socket featuring a nozzle-type contour at the orifice. Closing the mechanism led to the formation of a leading vortex ring with a dimensionless formation number of approximate ΔT*≈4. This indicates that the claw might work at maximum efficiency, i.e. maximum vortex strength was achieved by a minimum of fluid volume ejected. The subsequent vortex cavitation with the formation of an axial reentrant jet is a reasonable explanation for the large penetration depth of the water jet. That snapping shrimp can reach with their claw-induced flow. Within such a cavitation process, an axial reentrant jet is generated in the hollow cylindrical core of the cavitated vortex that pushes the front further downstream and whose length can exceed the initial jet penetration depth by several times.

  17. Hunting for ghosts in elastic snap-through

    NASA Astrophysics Data System (ADS)

    Gomez, Michael; Moulton, Derek E.; Vella, Dominic

    Elastic `snap-through' is a striking instability often seen when an elastic system loses bistability, e.g. due to a change in geometry or external loading. The switch from one state to another is generally rapid and hence is used to generate fast motions in biology and engineering. While the onset of instability has been well studied, the dynamics of the transition itself remain much less well understood. For example, the dynamics exhibited by children's jumping popper toys, or the leaves of the Venus flytrap plant, are much slower than would be expected based on a naive estimate of the elastic timescales. To explain this discrepancy, the natural conclusion has been drawn that some other effect, such as viscoelasticity, must play a role. We demonstrate here that purely elastic systems may show similar `slow' dynamics during snap-through. This behaviour is due to a remnant (or `ghost') of the snap-through bifurcation underlying the instability, analogously to bottleneck phenomena in 1-D dynamical systems. This slowness is a generic consequence of being close to bifurcation -- it does not require dissipation. We obtain scaling laws for the length of the delay and compare these to numerical simulations and experiments on real samples.

  18. Identification and Characterization of Botulinum Neurotoxin A Substrate Binding Pockets and Their Re-Engineering for Human SNAP-23.

    PubMed

    Sikorra, Stefan; Litschko, Christa; Müller, Carina; Thiel, Nadine; Galli, Thierry; Eichner, Timo; Binz, Thomas

    2016-01-29

    Botulinum neurotoxins (BoNTs) are highly potent bacterial proteins that block neurotransmitter release at the neuromuscular junction by cleaving SNAREs (soluble N-ethyl maleimide sensitive factor attachment protein receptors). However, their serotype A (BoNT/A) that cleaves SNAP-25 (synaptosomal-associated protein of 25 kDa) has also been an established pharmaceutical for treatment of medical conditions that rely on hyperactivity of cholinergic nerve terminals for 25 years. The expansion of its use to a variety of further medical conditions associated with hypersecretion components is prevented partly because the involved SNARE isoforms are not cleaved. Therefore, we examined by mutational analyses the reason for the resistance of human SNAP-23, an isoform of SNAP-25. We show that replacement of 10 SNAP-23 residues with their SNAP-25 counterparts effects SNAP-25-like cleavability. Conversely, transfer of each of the replaced SNAP-23 residues to SNAP-25 drastically decreased the cleavability of SNAP-25. By means of the existing SNAP-25-toxin co-crystal structure, molecular dynamics simulations, and corroborative mutagenesis studies, the appropriate binding pockets for these residues in BoNT/A were characterized. Systematic mutagenesis of two major BoNT/A binding pockets was conducted in order to adapt these pockets to corresponding amino acids of human SNAP-23. Human SNAP-23 cleaving mutants were isolated using a newly established yeast-based screening system. This method may be useful for engineering novel BoNT/A pharmaceuticals for the treatment of diseases that rely on SNAP-23-mediated hypersecretion. Copyright © 2015 Elsevier Ltd. All rights reserved.

  19. Applications Where Snap is BPM for Radioactive Waste Assay

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

    Miller, T.J.

    2008-07-01

    Historically, the Atomic Weapons Establishment (AWE) at Aldermaston in the United Kingdom (UK), has used a variety of assay techniques to measure the radioactive content of a diverse range of waste packages from decommissioning, operational and legacy sources. The regulator, the Environment Agency in the UK, places conditions and limits on AWE through an authorisation within the Radioactive Substances Act (RSA93). The conditions and limits require Best Practical Means (BPM) measurements to be used to demonstrate compliance with the authorisation. Hence, the assay technique employed needs to achieve a balance between risk of exposure, environmental considerations, technological considerations, health andmore » safety considerations and cost effectiveness, without being grossly disproportionate in terms of money, time or trouble. Recently published work has concluded that the Spectral Non-destructive Assay Platform (SNAP) assay system is BPM for Depleted Uranium (DU) waste assay at AWE (1) and low level plutonium in soft drummed waste, HEPA filters and soils (2-4). The purpose of this paper is to highlight other applications where SNAP represents BPM for radioactive waste assay. This has been done by intercomparison studies of SNAP with other assay techniques, such as Segmented Gamma Scanner (SGS) and Passive Neutron Coincidence Counter (PNCC). It has been concluded that, for a large range of waste packages encountered at AWE, SNAP is BPM. (author)« less

  20. Supplemental Nutrition Assistance Program (SNAP) Participation and Health Care Expenditures Among Low-Income Adults.

    PubMed

    Berkowitz, Seth A; Seligman, Hilary K; Rigdon, Joseph; Meigs, James B; Basu, Sanjay

    2017-11-01

    Food insecurity is associated with high health care expenditures, but the effectiveness of food insecurity interventions on health care costs is unknown. To determine whether the Supplemental Nutrition Assistance Program (SNAP), which addresses food insecurity, can reduce health care expenditures. This is a retrospective cohort study of 4447 noninstitutionalized adults with income below 200% of the federal poverty threshold who participated in the 2011 National Health Interview Survey (NHIS) and the 2012-2013 Medical Expenditure Panel Survey (MEPS). Self-reported SNAP participation in 2011. Total health care expenditures (all paid claims and out-of-pocket costs) in the 2012-2013 period. To test whether SNAP participation was associated with lower subsequent health care expenditures, we used generalized linear modeling (gamma distribution, log link, with survey design information), adjusting for demographics (age, gender, race/ethnicity), socioeconomic factors (income, education, Social Security Disability Insurance disability, urban/rural), census region, health insurance, and self-reported medical conditions. We also conducted sensitivity analyses as a robustness check for these modeling assumptions. A total of 4447 participants (2567 women and 1880 men) were enrolled in the study, mean (SE) age, 42.7 (0.5) years; 1889 were SNAP participants, and 2558 were not. Compared with other low-income adults, SNAP participants were younger (mean [SE] age, 40.3 [0.6] vs 44.1 [0.7] years), more likely to have public insurance or be uninsured (84.9% vs 67.7%), and more likely to be disabled (24.2% vs 10.6%) (P < .001 for all). In age- and gender-adjusted models, health care expenditures between those who did and did not participate in SNAP were similar (difference, $34; 95% CI, -$1097 to $1165). In fully adjusted models, SNAP was associated with lower estimated annual health care expenditures (-$1409; 95% CI, -$2694 to -$125). Sensitivity analyses were consistent with

  1. Episodic snapping of the medial head of the triceps due to weightlifting.

    PubMed

    Spinner, R J; Wenger, D E; Barry, C J; Goldner, R D

    1999-01-01

    We describe two patients who had episodic elbow snapping and ulnar nerve dysesthesias only after weightlifting. These symptoms would disappear soon afterward. The episodic nature of their complaints and findings led to misdiagnosis. We documented by repeated clinical examinations and magnetic resonance imaging that the presence of these symptoms correlated directly with the finding of intermittent, activity-related snapping of the medial triceps. In both patients, the symptoms disappeared when the medial portion of the triceps migrated medially but did not dislocate over the medial epicondyle with elbow flexion. Thus, a minor change in the configuration of the medial portion of the triceps (fluid accumulation) in the same individual at different times can cause intermittent dislocation of the medial triceps. Previous papers dealing with patients with snapping of the medial triceps describe symptoms exacerbated by athletic activities, but the constant finding of snapping on sequential examinations.

  2. α-SNAP regulates dynamic, on-site assembly and calcium selectivity of Orai1 channels

    PubMed Central

    Li, Peiyao; Miao, Yong; Dani, Adish; Vig, Monika

    2016-01-01

    Orai1 forms a highly calcium-selective pore of the calcium release activated channel, and α-SNAP is necessary for its function. Here we show that α-SNAP regulates on-site assembly of Orai1 dimers into calcium-selective multimers. We find that Orai1 is a dimer in resting primary mouse embryonic fibroblasts but displays variable stoichiometry in the plasma membrane of store-depleted cells. Remarkably, α-SNAP depletion induces formation of higher-order Orai1 oligomers, which permeate significant levels of sodium via Orai1 channels. Sodium permeation in α-SNAP–deficient cells cannot be corrected by tethering multiple Stim1 domains to Orai1 C-terminal tail, demonstrating that α-SNAP regulates functional assembly and calcium selectivity of Orai1 multimers independently of Stim1 levels. Fluorescence nanoscopy reveals sustained coassociation of α-SNAP with Stim1 and Orai1, and α-SNAP–depleted cells show faster and less constrained mobility of Orai1 within ER-PM junctions, suggesting Orai1 and Stim1 coentrapment without stable contacts. Furthermore, α-SNAP depletion significantly reduces fluorescence resonance energy transfer between Stim1 and Orai1 N-terminus but not C-terminus. Taken together, these data reveal a unique role of α-SNAP in the on-site functional assembly of Orai1 subunits and suggest that this process may, in part, involve enabling crucial low-affinity interactions between Orai1 N-terminus and Stim1. PMID:27335124

  3. Food Insecurity and SNAP Participation in Mexican Immigrant Families: The Impact of the Outreach Initiative

    PubMed Central

    Kaushal, Neeraj; Waldfogel, Jane; Wight, Vanessa

    2016-01-01

    We study the factors associated with food insecurity and participation in the Supplemental Nutrition Assistance Program (SNAP) in Mexican immigrant families in the US. Estimates from analyses that control for a rich set of economic, demographic, and geographic variables show that children in Mexican immigrant families are more likely to be food insecure than children in native families, but are less likely to participate in SNAP. Further, more vulnerable groups such as the first-generation Mexican immigrant families, families in the US for less than 5 years, and families with non-citizen children – that are at a higher risk of food insecurity are the least likely to participate in SNAP. Our analysis suggests that the US Department of Agriculture outreach initiative and SNAP expansion under the American Recovery and Reinvestment Act increased SNAP participation of the mixed-status Mexican families. We do not find any evidence that the outreach and ARRA expansion increased SNAP receipt among Mexican immigrant families with only non-citizen members who are likely to be undocumented. PMID:27570576

  4. 78 FR 52899 - Supplemental Nutrition Assistance Program (SNAP) Enhancing Retail Food Store Eligibility...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-27

    ... DEPARTMENT OF AGRICULTURE Food and Nutrition Service Supplemental Nutrition Assistance Program (SNAP) Enhancing Retail Food Store Eligibility--Listening Sessions AGENCY: Food and Nutrition Service... for Information (RFI) published by FNS regarding Supplemental Nutrition Assistance Program (SNAP...

  5. Shock and vibration tests of a SNAP-8 NaK pump

    NASA Technical Reports Server (NTRS)

    Stromquist, A. J.; Nelson, R. B.; Hibben, L.

    1971-01-01

    The pump used for reactor cooling in the SNAP 8 space power system was subjected to the expected vehicle launch vibration, and shock loading in accordance with the SNAP 8 environmental specification. Subsequent disassembly revealed damage to the thrust bearing pins, which should be redesigned and strengthened. The unit was operational, however, when run in a test loop after reassembly.

  6. Production Program - Operational - SNAP 10A Units

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

    None

    1961-08-07

    This planning report is provided to describe the lead time, approximate costs, and major decisions and approvals required to enter a production program for the 500 watt SNAP 10A nuclear space power system.

  7. Scapulothoracic bursitis and snapping scapula syndrome: a critical review of current evidence.

    PubMed

    Warth, Ryan J; Spiegl, Ulrich J; Millett, Peter J

    2015-01-01

    Symptomatic scapulothoracic disorders, such as painful scapular crepitus and/or bursitis, are uncommon; however, they can produce significant pain and disability in many patients. To review the current knowledge pertaining to snapping scapula syndrome and to identify areas of further research that may be helpful to improve clinical outcomes and patient satisfaction. Systematic review. We performed a preliminary search of the PubMed and Embase databases using the search terms "snapping scapula," "scapulothoracic bursitis," "partial scapulectomy," and "superomedial angle resection" in September 2013. All nonreview articles related to the topic of snapping scapula syndrome were included. The search identified a total of 167 unique articles, 81 of which were relevant to the topic of snapping scapula syndrome. There were 36 case series of fewer than 10 patients, 16 technique papers, 11 imaging studies, 9 anatomic studies, and 9 level IV outcomes studies. The level of evidence obtained from this literature search was inadequate to perform a formal systematic review or meta-analysis. Therefore, a critical review of current evidence is presented. Snapping scapula syndrome, a likely underdiagnosed condition, can produce significant shoulder dysfunction in many patients. Because the precise origin is typically unknown, specific treatments that are effective for some patients may not be effective for others. Nevertheless, bursectomy with or without partial scapulectomy is currently the most effective primary method of treatment in patients who fail nonoperative therapy. However, many patients experience continued shoulder disability even after surgical intervention. Future studies should focus on identifying the modifiable factors associated with poor outcomes after operative and nonoperative management for snapping scapula syndrome in an effort to improve clinical outcomes and patient satisfaction. © 2014 The Author(s).

  8. Snap-through instability analysis of dielectric elastomers with consideration of chain entanglements

    NASA Astrophysics Data System (ADS)

    Zhu, Jiakun; Luo, Jun; Xiao, Zhongmin

    2018-06-01

    It is widely recognized that the extension limit of polymer chains has a significant effect on the snap-through instability of dielectric elastomers (DEs). The snap-through instability performance of DEs has been extensively studied by two limited-stretch models, i.e., the eight-chain model and Gent model. However, the real polymer networks usually have many entanglements due to the impenetrability of the network chains as well as a finite extensibility resulting from the full stretching of the polymer chains. The effects of entanglements on the snap-through instability of DEs cannot be captured by the previous two limited-stretch models. In this paper, the nonaffine model proposed by Davidson and Goulbourne is adopted to characterize the influence of entanglements and extension limit of the polymer chains. It is demonstrated that the nonaffine model is almost identical to the eight-chain model and is close to the Gent model if we ignore the effects of chain entanglements and adopt the affine assumption. The suitability of the nonaffine model to characterize the mechanical behavior of elastomers is validated by fitting the experimental results reported in the open literature. After that, the snap-through stability performance of an ideal DE membrane under equal-biaxial prestretches is studied with the nonaffine model. It is revealed that besides the prestretch and chain extension limit, the chain entanglements can markedly influence the snap-through instability and the path to failure of DEs. These results provide a more comprehensive understanding on the snap-through instability of a DE and may be helpful to guide the design of DE devices.

  9. Probing gravity theory and cosmic acceleration using (in)consistency tests between cosmological data sets

    NASA Astrophysics Data System (ADS)

    Ishak-Boushaki, Mustapha B.

    2018-06-01

    Testing general relativity at cosmological scales and probing the cause of cosmic acceleration are among important objectives targeted by incoming and future astronomical surveys and experiments. I present our recent results on (in)consistency tests that can provide insights about the underlying gravity theory and cosmic acceleration using cosmological data sets. We use new statistical measures that can detect discordances between data sets when present. We use an algorithmic procedure based on these new measures that is able to identify in some cases whether an inconsistency is due to problems related to systematic effects in the data or to the underlying model. Some recent published tensions between data sets are also examined using our formalism, including the Hubble constant measurements, Planck and Large-Scale-Structure. (Work supported in part by NSF under Grant No. AST-1517768).

  10. Validation of a Computerized Adaptive Version of the Schedule for Nonadaptive and Adaptive Personality (SNAP)

    ERIC Educational Resources Information Center

    Simms, Leonard J.; Clark, Lee Anna

    2005-01-01

    This is a validation study of a computerized adaptive (CAT) version of the Schedule for Nonadaptive and Adaptive Personality (SNAP) conducted with 413 undergraduates who completed the SNAP twice, 1 week apart. Participants were assigned randomly to 1 of 4 retest groups: (a) paper-and-pencil (P&P) SNAP, (b) CAT, (c) P&P/CAT, and (d) CAT/P&P. With…

  11. Experimental Criticality Benchmarks for SNAP 10A/2 Reactor Cores

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

    Krass, A.W.

    2005-12-19

    This report describes computational benchmark models for nuclear criticality derived from descriptions of the Systems for Nuclear Auxiliary Power (SNAP) Critical Assembly (SCA)-4B experimental criticality program conducted by Atomics International during the early 1960's. The selected experimental configurations consist of fueled SNAP 10A/2-type reactor cores subject to varied conditions of water immersion and reflection under experimental control to measure neutron multiplication. SNAP 10A/2-type reactor cores are compact volumes fueled and moderated with the hydride of highly enriched uranium-zirconium alloy. Specifications for the materials and geometry needed to describe a given experimental configuration for a model using MCNP5 are provided. Themore » material and geometry specifications are adequate to permit user development of input for alternative nuclear safety codes, such as KENO. A total of 73 distinct experimental configurations are described.« less

  12. SNAP-25 requirement for dendritic growth of hippocampal neurons.

    PubMed

    Grosse, G; Grosse, J; Tapp, R; Kuchinke, J; Gorsleben, M; Fetter, I; Höhne-Zell, B; Gratzl, M; Bergmann, M

    1999-06-01

    Structure and dimension of the dendritic arbor are important determinants of information processing by the nerve cell, but mechanisms and molecules involved in dendritic growth are essentially unknown. We investigated early mechanisms of dendritic growth using mouse fetal hippocampal neurons in primary culture, which form processes during the first week in vitro. We detected a key component of regulated exocytosis, SNAP-25 (synaptosomal associated protein of 25 kDa), in axons and axonal terminals as well as in dendrites identified by the occurrence of the dendritic markers transferrin receptor and MAP2. Selective inactivation of SNAP-25 by botulinum neurotoxin A (BoNTA) resulted in inhibition of axonal growth and of vesicle recycling in axonal terminals. In addition, dendritic growth of hippocampal pyramidal and granule neurons was significantly inhibited by BoNTA. In contrast, cleavage of synaptobrevin by tetanus toxin had an effect on neither axonal nor dendritic growth. Our observations indicate that SNAP-25, but not synaptobrevin, is involved in constitutive axonal growth and dendrite formation by hippocampal neurons.

  13. Cell-Specific Loss of SNAP25 from Cortical Projection Neurons Allows Normal Development but Causes Subsequent Neurodegeneration.

    PubMed

    Hoerder-Suabedissen, Anna; Korrell, Kim V; Hayashi, Shuichi; Jeans, Alexander; Ramirez, Denise M O; Grant, Eleanor; Christian, Helen C; Kavalali, Ege T; Wilson, Michael C; Molnár, Zoltán

    2018-05-30

    Synaptosomal associated protein 25 kDa (SNAP25) is an essential component of the SNARE complex regulating synaptic vesicle fusion. SNAP25 deficiency has been implicated in a variety of cognitive disorders. We ablated SNAP25 from selected neuronal populations by generating a transgenic mouse (B6-Snap25tm3mcw (Snap25-flox)) with LoxP sites flanking exon5a/5b. In the presence of Cre-recombinase, Snap25-flox is recombined to a truncated transcript. Evoked synaptic vesicle release is severely reduced in Snap25 conditional knockout (cKO) neurons as shown by live cell imaging of synaptic vesicle fusion and whole cell patch clamp recordings in cultured hippocampal neurons. We studied Snap25 cKO in subsets of cortical projection neurons in vivo (L5-Rbp4-Cre; L6-Ntsr1-Cre; L6b-Drd1a-Cre). cKO neurons develop normal axonal projections, but axons are not maintained appropriately, showing signs of swelling, fragmentation and eventually complete absence. Onset and progression of degeneration are dependent on the neuron type, with L5 cells showing the earliest and most severe axonal loss. Ultrastructural examination revealed that cKO neurites contain autophagosome/lysosome-like structures. Markers of inflammation such as Iba1 and lipofuscin are increased only in adult cKO cortex. Snap25 cKO can provide a model to study genetic interactions with environmental influences in several disorders.

  14. The SNAP System for Inservice Training of Regular Educators. Final Project Report.

    ERIC Educational Resources Information Center

    Malouf, David B.; Pilato, Virginia H.

    This report discusses a project to develop, test, and disseminate the SNAP (Smart Needs Assessment Program) system for needs assessment and inservice training of regular educators to work with students with disabilities. The SNAP system is an expert system that defines the training needs of individual teachers and links these needs with training…

  15. A comparison of bottles and snap traps for short-term small mammal sampling

    Treesearch

    James F. Taulman; Ronald E. Thill; T. Bently Wigley; M. Anthony Melchiors

    1992-01-01

    Bottles were tested as traps for small mammals. Used in conjunction with three types of snap traps over 30,240 trap nights, bottles captured eight (2%) of the total 421 mammals taken. Bottles were inefficient in capturing small mammals compared to snap traps.

  16. Myosin phosphatase and RhoA-activated kinase modulate neurotransmitter release by regulating SNAP-25 of SNARE complex

    PubMed Central

    Sipos, Adrienn; Darula, Zsuzsanna; Bécsi, Bálint; Nagy, Dénes; Iván, Judit; Erdődi, Ferenc

    2017-01-01

    Reversible phosphorylation of neuronal proteins plays an important role in the regulation of neurotransmitter release. Myosin phosphatase holoenzyme (MP) consists of a protein phosphatase-1 (PP1) catalytic subunit (PP1c) and a regulatory subunit, termed myosin phosphatase targeting subunit (MYPT1). The primary function of MP is to regulate the phosphorylation level of contractile proteins; however, recent studies have shown that MP is localized to neurons, and is also involved in the mediation of neuronal processes. Our goal was to investigate the effect of RhoA-activated kinase (ROK) and MP on the phosphorylation of one potential neuronal substrate, the synaptosomal-associated protein of 25 kDa (SNAP-25). SNAP-25 is a member of the SNARE (soluble N-ethylmaleimide sensitive factor attachment protein receptor) complex, along with synaptobrevin and syntaxin, and the primary role of SNAP25 is to mediate vesicle fusion. We showed that MYPT1 interacts with SNAP-25, as revealed by immunoprecipitation and surface plasmon resonance based binding studies. Mass spectrometry analysis and in vitro phosphorylation/dephosphorylation assays demonstrated that ROK phosphorylates, while MP dephosphorylates, SNAP-25 at Thr138. Silencing MYPT1 in B50 neuroblastoma cells increased phosphorylation of SNAP-25 at Thr138. Inhibition of PP1 with tautomycetin increased, whereas inhibition of ROK by H1152, decreased the phosphorylation of SNAP-25 at Thr138 in B50 cells, in cortical synaptosomes, and in brain slices. In response to the transduction of the MP inhibitor, kinase-enhanced PP1 inhibitor (KEPI), into synaptosomes, an increase in phosphorylation of SNAP-25 and a decrease in the extent of neurotransmitter release were detected. The interaction between SNAP-25 and syntaxin increased with decreasing phosphorylation of SNAP-25 at Thr138, upon inhibition of ROK. Our data suggest that ROK/MP play a crucial role in vesicle trafficking, fusion, and neurotransmitter release by oppositely

  17. Mammalian DNA enriched for replication origins is enriched for snap-back sequences.

    PubMed

    Zannis-Hadjopoulos, M; Kaufmann, G; Martin, R G

    1984-11-15

    Using the instability of replication loops as a method for the isolation of double-stranded nascent DNA, extruded DNA enriched for replication origins was obtained and denatured. Snap-back DNA, single-stranded DNA with inverted repeats (palindromic sequences), reassociates rapidly into stem-loop structures with zero-order kinetics when conditions are changed from denaturing to renaturing, and can be assayed by chromatography on hydroxyapatite. Origin-enriched nascent DNA strands from mouse, rat and monkey cells growing either synchronously or asynchronously were purified and assayed for the presence of snap-back sequences. The results show that origin-enriched DNA is also enriched for snap-back sequences, implying that some origins for mammalian DNA replication contain or lie near palindromic sequences.

  18. SNAP Participants' Eating Patterns over the Benefit Month: A Time Use Perspective.

    PubMed

    Hamrick, Karen S; Andrews, Margaret

    2016-01-01

    Individuals receiving monthly benefits through the U.S. Supplemental Nutrition Assistance Program (SNAP) often fall short of food at the end of the month and some report feelings of hunger. To investigate this situation, we used time diaries from the 2006-08 American Time Use Survey and Eating & Health Module to identify the timing of days where respondents reported no eating occurrences. Analysis includes descriptive statistics, a logit model, and a simulated benefit month. We found that SNAP participants were increasingly more likely than nonparticipants to report a day with no eating occurrences over the benefit issuance cycle. This supports the view that there is a monthly cycle in food consumption associated with the SNAP monthly benefit issuance policy.

  19. The development of Version 2 of the AN-SNAP casemix classification system.

    PubMed

    Green, Janette; Gordon, Robert

    2007-04-01

    This paper presents the results of a recent review of the Australian National Sub-acute and Non-acute Patient (AN-SNAP) classification system. The AN-SNAP system was developed by the Centre for Health Service Development, University of Wollongong in 1997. The review was conducted between August 2005 and September 2006. Four clinical sub-committees comprising more than 50 clinicians from sub-acute services across New South Wales as well as representatives from Queensland and the Australian Capital Territory were established to develop a set of proposals to be considered for incorporation into Version 2 of the classification. It is proposed that the final AN-SNAP Version 2 classification will be available for implementation from 1 July 2007.

  20. Syntheses of precursors and reference compounds of the melanin-concentrating hormone receptor 1 (MCHR1) tracers [¹¹C]SNAP-7941 and [¹⁸F]FE@SNAP for positron emission tomography.

    PubMed

    Schirmer, Eva; Shanab, Karem; Datterl, Barbara; Neudorfer, Catharina; Mitterhauser, Markus; Wadsak, Wolfgang; Philippe, Cécile; Spreitzer, Helmut

    2013-09-30

    The MCH receptor has been revealed as a target of great interest in positron emission tomography imaging. The receptor's eponymous substrate melanin-concentrating hormone (MCH) is a cyclic peptide hormone, which is located predominantly in the hypothalamus with a major influence on energy and weight regulation as well as water balance and memory. Therefore, it is thought to play an important role in the pathophysiology of adiposity, which is nowadays a big issue worldwide. Based on the selective and high-affinity MCH receptor 1 antagonist SNAP-7941, a series of novel SNAP derivatives has been developed to provide different precursors and reference compounds for the radiosyntheses of the novel PET radiotracers [(11)C]SNAP-7941 and [(18)F]FE@SNAP. Positron emission tomography promotes a better understanding of physiologic parameters on a molecular level, thus giving a deeper insight into MCHR1 related processes as adiposity.

  1. SNAP-8 electrical generating system development program

    NASA Technical Reports Server (NTRS)

    1971-01-01

    The SNAP-8 program has developed the technology base for one class of multikilowatt dynamic space power systems. Electrical power is generated by a turbine-alternator in a mercury Rankine-cycle loop to which heat is transferred and removed by means of sodium-potassium eutectic alloy subsystems. Final system overall criteria include a five-year operating life, restartability, man rating, and deliverable power in the 90 kWe range. The basic technology has been demonstrated by more than 400,000 hours of major component endurance testing and numerous startup and shutdown cycles. A test system, comprised of developed components, delivered up to 35 kWe for a period exceeding 12,000 hours. The SNAP-8 system baseline is considered to have achieved a level of technology suitable for final application development for long-term multikilowatt space missions.

  2. SNAP-8 electrical generating system development program

    NASA Technical Reports Server (NTRS)

    1971-01-01

    The SNAP-8 program has developed the technology base for one class of multikilowatt dynamic space power systems. Electrical power is generated by a turbine-alternator in a mercury Rankine-cycle loop to which heat is transferred and removed by means of sodium-potassium eutectic alloy subsystems. Final system overall criteria include a five-year operating life, restartability, man rating, and deliverable power in the 90 kWe range. The basic technology was demonstrated by more than 400,000 hours of major component endurance testing and numerous startup and shutdown cycles. A test system, comprised of developed components, delivered up to 35 kWe for a period exceeding 12,000 hours. The SNAP-8 system baseline is considered to have achieved a level of technology suitable for final application development for long-term multikilowatt space missions.

  3. Strategies to improve the dietary quality of Supplemental Nutrition Assistance Program (SNAP) beneficiaries: an assessment of stakeholder opinions.

    PubMed

    Blumenthal, Susan J; Hoffnagle, Elena E; Leung, Cindy W; Lofink, Hayley; Jensen, Helen H; Foerster, Susan B; Cheung, Lilian Wy; Nestle, Marion; Willett, Walter C

    2014-12-01

    To examine the opinions of stakeholders on strategies to improve dietary quality of Supplemental Nutrition Assistance Program (SNAP) participants. Participants answered a thirty-eight-item web-based survey assessing opinions and perceptions of SNAP and programme policy changes. Survey of 522 individuals with stakeholder interest in SNAP, conducted in October through December 2011. The top three barriers to improving dietary quality identified were: (i) unhealthy foods marketed in low-income communities; (ii) the high cost of healthy foods; and (iii) lifestyle challenges faced by low-income individuals. Many respondents (70 %) also disagreed that current SNAP benefit levels were adequate to maintain a healthy diet. Stakeholders believed that vouchers, coupons or monetary incentives for purchasing healthful foods might have the greatest potential for improving the diets of SNAP participants. Many respondents (78 %) agreed that sodas should not be eligible for purchases with SNAP benefits. More than half (55 %) believed retailers could easily implement such restrictions. A majority of respondents (58 %) agreed that stores should stock a minimum quantity of healthful foods in order to be certified as a SNAP retailer, and most respondents (83 %) believed that the US Department of Agriculture should collect data on the foods purchased with SNAP benefits. Results suggest that there is broad stakeholder support for policies that align SNAP purchase eligibility with national public health goals of reducing food insecurity, improving nutrition and preventing obesity.

  4. Developmental and diurnal expression of the synaptosomal-associated protein 25 (Snap25) in the rat pineal gland.

    PubMed

    Karlsen, Anna S; Rath, Martin F; Rohde, Kristian; Toft, Trine; Møller, Morten

    2013-06-01

    Snap25 (synaptosomal-associated protein) is a 25 kDa protein, belonging to the SNARE-family (soluble N-ethylmaleimide-sensitive factor attachment protein receptors) of proteins, essential for synaptic and secretory vesicle exocytosis. Snap25 has by immunohistochemistry been demonstrated in the rat pineal gland but the biological importance of this is unknown. In this study, we demonstrate a high expression of mRNA encoding Snap25 in all parts of the rat pineal complex, the superficial-, and deep-pineal gland, as well as in the pineal stalk. Snap25 showed a low pineal expression during embryonic stages with a strong increase in expression levels just after birth. The expression showed no day/night variations. Neither removal of the sympathetic input to the pineal gland by superior cervical ganglionectomy nor bilateral decentralization of the superior cervical ganglia significantly affected the expression of Snap25 in the gland. The pineal expression levels of Snap25 were not changed following intraperitoneal injection of isoproterenol. The strong expression of Snap25 in the pineal gland suggests the presence of secretory granules and microvesicles in the rat pinealocyte supporting the concept of a vesicular release. At the transcriptional level, this Snap25-based release mechanism does not exhibit any diurnal rhythmicity and is regulated independently of the sympathetic nervous input to the gland.

  5. Concentration of tobacco advertisements at SNAP and WIC stores, Philadelphia, Pennsylvania, 2012.

    PubMed

    Hillier, Amy; Chilton, Mariana; Zhao, Qian-Wei; Szymkowiak, Dorota; Coffman, Ryan; Mallya, Giridhar

    2015-02-05

    Tobacco advertising is widespread in urban areas with racial/ethnic minority and low-income households that participate in nutrition assistance programs. Tobacco sales and advertising are linked to smoking behavior, which may complicate matters for low-income families struggling with disparate health risks relating to nutrition and chronic disease. We investigated the relationship between the amount and type of tobacco advertisements on tobacco outlets and the outlet type and location. By using field visits and online images, we inspected all licensed tobacco retail outlets in Philadelphia (N = 4,639). Point pattern analyses were used to identify significant clustering of tobacco outlets and outlets with exterior tobacco advertisements. Logistic regression was used to analyze the relationship between the outlet's acceptance of Supplemental Nutrition Assistance Program (SNAP) and Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) and the presence of tobacco advertisements. Tobacco outlets with exterior tobacco advertisements were significantly clustered in several high-poverty areas. Controlling for racial/ethnic and income composition and land use, SNAP and WIC vendors were significantly more likely to have exterior (SNAP odds ratio [OR], 2.11; WIC OR, 1.59) and interior (SNAP OR, 3.43; WIC OR, 1.69) tobacco advertisements than other types of tobacco outlets. Tobacco advertising is widespread at retail outlets, particularly in low-income and racial/ethnic minority neighborhoods. Policy makers may be able to mitigate the effects of this disparate exposure through tobacco retail licensing, local sign control rules, and SNAP and WIC authorization.

  6. α-SNAP Interferes with the Zippering of the SNARE Protein Membrane Fusion Machinery

    PubMed Central

    Park, Yongsoo; Vennekate, Wensi; Yavuz, Halenur; Preobraschenski, Julia; Hernandez, Javier M.; Riedel, Dietmar; Walla, Peter Jomo; Jahn, Reinhard

    2014-01-01

    Neuronal exocytosis is mediated by soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteins. Before fusion, SNARE proteins form complexes bridging the membrane followed by assembly toward the C-terminal membrane anchors, thus initiating membrane fusion. After fusion, the SNARE complex is disassembled by the AAA-ATPase N-ethylmaleimide-sensitive factor that requires the cofactor α-SNAP to first bind to the assembled SNARE complex. Using chromaffin granules and liposomes we now show that α-SNAP on its own interferes with the zippering of membrane-anchored SNARE complexes midway through the zippering reaction, arresting SNAREs in a partially assembled trans-complex and preventing fusion. Intriguingly, the interference does not result in an inhibitory effect on synaptic vesicles, suggesting that membrane properties also influence the final outcome of α-SNAP interference with SNARE zippering. We suggest that binding of α-SNAP to the SNARE complex affects the ability of the SNARE complex to harness energy or transmit force to the membrane. PMID:24778182

  7. Role of "Sural Sparing" Pattern (Absent/Abnormal Median and Ulnar with Present Sural SNAP) Compared to Absent/Abnormal Median or Ulnar with Normal Sural SNAP in Acute Inflammatory Demyelinating Polyneuropathy.

    PubMed

    Surpur, Spurthi Sunil; Govindarajan, Raghav

    2017-01-01

    Sural sparing defined as absent/abnormal median sensory nerve action potential (SNAP) amplitude or absent/abnormal ulnar SNAP amplitude with a normal sural SNAP amplitude is thought to be a marker for inflammatory demyelinating polyneuropathies. If sural sparing pattern specifically defined as absent/abnormal median and ulnar SNAP amplitude with normal sural SNAP amplitude (AMUNS) is sensitive and specific when compared with either absent/abnormal median and normal sural (AMNS) or absent/abnormal ulnar and normal sural (AUNS) for acute inflammatory demyelinating polyneuropathy (AIDP), chronic inflammatory demyelinating polyneuropathy (CIDP), select non-diabetic axonopathies (AXPs), and diabetic neuropathies (DNs). Retrospective analysis from 2001 to 2010 on all newly diagnosed AIDP, CIDP, select non-diabetic AXP, and DN. There were 20 AIDP and 23 CIDP. Twenty AXP and 50 DN patients between 2009 and 2010 were included as controls. AMUNS was seen in 65% of AIDP, 39% CIDP compared with 10% of AXP and 6% for DN with sensitivity of 51%, specificity of 92%, whereas the specificity of AMNS/AUNS was 73% and its sensitivity was 58%. If a patient has AMUNS they are >12 times more likely to have AIDP ( p  < 0.001). Sural sparing is highly specific but not sensitive when compared with either AMNS or AUNS in AIDP but does not add to sensitivity or specificity in CIDP.

  8. Van Allen Probes Observations of Radiation Belt Acceleration associated with Solar Wind Shocks

    NASA Astrophysics Data System (ADS)

    Foster, J. C.; Wygant, J. R.; Baker, D. N.

    2017-12-01

    During a moderate solar wind shock event on 8 October 2013 the twin Van Allen Probes spacecraft observed the shock-induced electric field in the dayside magnetosphere and the response of the electron populations across a broad range of energies. Whereas other mechanisms populating the radiation belts close to Earth (L 3-5) take place on time scales of months (diffusion) or hours (storm and substorm effects), acceleration during shock events occurs on a much faster ( 1 minute) time scale. During this event the dayside equatorial magnetosphere experienced a strong dusk-dawn/azimuthal component of the electric field of 1 min duration. This shock-induced pulse accelerates radiation belt electrons for the length of time they are exposed to it creating "quasi-periodic pulse-like" enhancements in the relativistic (2 - 6 MeV) electron flux. Electron acceleration occurs on a time scale that is a fraction of their orbital drift period around the Earth. Those electrons whose drift velocity closely matches the azimuthal phase velocity of the shock-induced pulse stay in the accelerating wave as it propagates tailward and receive the largest increase in energy. Relativistic electron gradient drift velocities are energy-dependent, selecting a preferred range of energies (3-4 MeV) for the strongest enhancement. The time scale for shock acceleration is short with respect to the electron drift period ( 5 min), but long with respect to bounce and gyro periodicities. As a result, the third invariant is broken and the affected electron populations are displaced earthward experiencing an adiabatic energy gain. At radial distances tailward of the peak in phase space density, the impulsive inward displacement of the electron population produces a decrease in electron flux and a sequence of gradient drifting "negative holes".Dual spacecraft coverage of the 8 October 2013 event provided a before/after time sequence documenting shock effects.

  9. Loss of a membrane trafficking protein αSNAP induces non-canonical autophagy in human epithelia

    PubMed Central

    Naydenov, Nayden G.; Harris, Gianni; Morales, Victor; Ivanov, Andrei I.

    2012-01-01

    Autophagy is a catabolic process that sequesters intracellular proteins and organelles within membrane vesicles called autophagosomes with their subsequent delivery to lyzosomes for degradation. This process involves multiple fusions of autophagosomal membranes with different vesicular compartments; however, the role of vesicle fusion in autophagosomal biogenesis remains poorly understood. This study addresses the role of a key vesicle fusion regulator, soluble N-ethylmaleimide-sensitive factor attachment protein α (αSNAP), in autophagy. Small interfering RNA-mediated downregulation of αSNAP expression in cultured epithelial cells stimulated the autophagic flux, which was manifested by increased conjugation of microtubule-associated protein light chain 3 (LC3-II) and accumulation of LC3-positive autophagosomes. This enhanced autophagy developed via a non-canonical mechanism that did not require beclin1-p150-dependent nucleation, but involved Atg5 and Atg7-mediated elongation of autophagosomal membranes. Induction of autophagy in αSNAP-depleted cells was accompanied by decreased mTOR signaling but appeared to be independent of αSNAP-binding partners, N-ethylmaleimide-sensitive factor and BNIP1. Loss of αSNAP caused fragmentation of the Golgi and downregulation of the Golgi-specific GTP exchange factors, GBF1, BIG1 and BIG2. Pharmacological disruption of the Golgi and genetic inhibition of GBF1 recreated the effects of αSNAP depletion on the autophagic flux. Our study revealed a novel role for αSNAP as a negative regulator of autophagy that acts by enhancing mTOR signaling and regulating the integrity of the Golgi complex. PMID:23187805

  10. Poor Dietary Guidelines Compliance among Low-Income Women Eligible for Supplemental Nutrition Assistance Program-Education (SNAP-Ed).

    PubMed

    Jun, Shinyoung; Thuppal, Sowmyanarayanan V; Maulding, Melissa K; Eicher-Miller, Heather A; Savaiano, Dennis A; Bailey, Regan L

    2018-03-08

    The Supplemental Nutrition Assistance Program-Education (SNAP-Ed) program aims to improve nutritional intakes of low-income individuals (<185% poverty threshold). The objective of this study was to describe the compliance with Dietary Guidelines for Americans (DGA) recommendations for fruits, vegetables, and whole grains among SNAP-Ed eligible ( n = 3142) and ineligible ( n = 3168) adult women (19-70 years) nationwide and SNAP-Ed participating women in Indiana ( n = 2623), using the NHANES 2007-2012 and Indiana SNAP-Ed survey data, respectively. Sensitivity analysis further stratified women by race/ethnicity and by current SNAP participation (<130% poverty threshold). Nationally, lower-income women were less likely to meet the fruit (21% vs. 25%) and vegetable (11% vs. 19%) guidelines than higher-income women, but did not differ on whole grains, which were ~5% regardless of income. The income differences in fruit and vegetable intakes were driven by non-Hispanic whites. Fewer SNAP-Ed-eligible U.S. women met fruit (21% vs. 55%) and whole grain (4% vs. 18%) but did not differ for vegetable recommendations (11% vs. 9%) when compared to Indiana SNAP-Ed women. This same trend was observed among current SNAP participants. Different racial/ethnic group relationships with DGA compliance were found in Indiana compared to the nation. Nevertheless, most low-income women in the U.S. are at risk of not meeting DGA recommendations for fruits (79%), vegetables (89%), and whole grains (96%); SNAP-Ed participants in Indiana had higher compliance with DGA recommendations. Increased consumption of these three critical food groups would improve nutrient density, likely reduce calorie consumption by replacing high calorie choices, and improve fiber intakes.

  11. Strategies to Improve the Dietary Quality of Supplemental Nutrition Assistance Program (SNAP) Beneficiaries: An Assessment of Stakeholder Opinions

    PubMed Central

    Blumenthal, Susan J.; Hoffnagle, Elena E.; Leung, Cindy W.; Lofink, Hayley; Jensen, Helen H.; Foerster, Susan B.; Cheung, Lilian W.Y.; Nestle, Marion; Willet, Walter C.

    2013-01-01

    Objective To examine the opinions of stakeholders on strategies to improve dietary quality of Supplemental Nutrition Assistance Program (SNAP) participants. Design Participants answered a 38-item web-based survey assessing opinions and perceptions of SNAP and program policy changes. Setting U.S.A. Subjects Survey of 522 individuals with stakeholder interest in the Supplemental Nutrition Assistance Program (SNAP) conducted in October through December 2011. Results The top three barriers to improving dietary quality identified were: 1) unhealthy foods marketed in low-income communities; 2) the high cost of healthy foods; and 3) lifestyle challenges faced by low-income individuals. Many respondents (70%) also disagreed that current SNAP benefit levels were adequate to maintain a healthy diet. Stakeholders believed that vouchers, coupons, or monetary incentives for purchasing healthful foods might have the greatest potential for improving the diets of SNAP participants. Many respondents (78%) agreed that sodas should not be eligible for purchases with SNAP benefits. More than half (55%) believed retailers could easily implement such restrictions. A majority of respondents (58%) agreed that stores should stock a minimum quantity of healthful foods in order to be certified as a SNAP retailer, and most respondents (83%) believed that the USDA should collect data on the foods purchased with SNAP benefits. Conclusions Results suggest that there is broad stakeholder support for policies that align SNAP purchase eligibility with national public health goals of reducing food insecurity, improving nutrition and preventing obesity. PMID:24476898

  12. SNAP Participants’ Eating Patterns over the Benefit Month: A Time Use Perspective

    PubMed Central

    2016-01-01

    Individuals receiving monthly benefits through the U.S. Supplemental Nutrition Assistance Program (SNAP) often fall short of food at the end of the month and some report feelings of hunger. To investigate this situation, we used time diaries from the 2006–08 American Time Use Survey and Eating & Health Module to identify the timing of days where respondents reported no eating occurrences. Analysis includes descriptive statistics, a logit model, and a simulated benefit month. We found that SNAP participants were increasingly more likely than nonparticipants to report a day with no eating occurrences over the benefit issuance cycle. This supports the view that there is a monthly cycle in food consumption associated with the SNAP monthly benefit issuance policy. PMID:27410962

  13. Method for reducing snap in magnetic amplifiers

    NASA Technical Reports Server (NTRS)

    Fischer, R. L. E.; Word, J. L.

    1968-01-01

    Method of reducing snap in magnetic amplifiers uses a degenerative feedback circuit consisting of a resistor and a separate winding on a magnetic core. The feedback circuit extends amplifier range by allowing it to be used at lower values of output current.

  14. Innovative, wearable snap connector technology for improved device networking in electronic garments

    NASA Astrophysics Data System (ADS)

    Kostrzewski, Andrew A.; Lee, Kang S.; Gans, Eric; Winterhalter, Carole A.; Jannson, Tomasz P.

    2007-04-01

    This paper discusses Physical Optics Corporation's (POC) wearable snap connector technology that provides for the transfer of data and power throughout an electronic garment (e-garment). These connectors resemble a standard garment button and can be mated blindly with only one hand. Fully compatible with military clothing, their application allows for the networking of multiple electronic devices and an intuitive method for adding/removing existing components from the system. The attached flexible cabling also permits the rugged snap connectors to be fed throughout the standard webbing found in military garments permitting placement in any location within the uniform. Variations of the snap electronics/geometry allow for integration with USB 2.0 devices, RF antennas, and are capable of transferring high bandwidth data streams such as the 221 Mbps required for VGA video. With the trend towards providing military officers with numerous electronic devices (i.e., heads up displays (HMD), GPS receiver, PDA, etc), POC's snap connector technology will greatly improve cable management resulting in a less cumbersome uniform. In addition, with electronic garments gaining widespread adoption in the commercial marketplace, POC's technology is finding applications in such areas as sporting good manufacturers and video game technology.

  15. ACCELERATION INTEGRATING MEANS

    DOEpatents

    Wilkes, D.F.

    1961-08-29

    An acceleration responsive device is described. A housing has at one end normally open electrical contacts and contains a piston system with a first part of non-magnetic material having metering orifices in the side walls for forming an air bearing between it and the walls of the housing; this first piston part is normally held against the other end of the housing from the noted contacts by a second piston or reset part. The reset part is of partly magnetic material, is separable from the flrst piston part, and is positioned within the housing intermediate the contacts and the first piston part. A magnet carried by the housing imposes a retaining force upon the reset part, along with a helical compression spring that is between the reset part and the end with the contacts. When a predetermined acceleration level is attained, the reset part overcomes the bias or retaining force provided by the magnet and the spring'' snaps'' into a depression in the housing adjacent the contacts. The first piston part is then free to move toward the contacts with its movement responsive tc acceleration forces and the metering orifices. (AEC)

  16. Concentration of Tobacco Advertisements at SNAP and WIC Stores, Philadelphia, Pennsylvania, 2012

    PubMed Central

    Chilton, Mariana; Zhao, Qian-Wei; Szymkowiak, Dorota; Coffman, Ryan; Mallya, Giridhar

    2015-01-01

    Introduction Tobacco advertising is widespread in urban areas with racial/ethnic minority and low-income households that participate in nutrition assistance programs. Tobacco sales and advertising are linked to smoking behavior, which may complicate matters for low-income families struggling with disparate health risks relating to nutrition and chronic disease. We investigated the relationship between the amount and type of tobacco advertisements on tobacco outlets and the outlet type and location. Methods By using field visits and online images, we inspected all licensed tobacco retail outlets in Philadelphia (N = 4,639). Point pattern analyses were used to identify significant clustering of tobacco outlets and outlets with exterior tobacco advertisements. Logistic regression was used to analyze the relationship between the outlet’s acceptance of Supplemental Nutrition Assistance Program (SNAP) and Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) and the presence of tobacco advertisements. Results Tobacco outlets with exterior tobacco advertisements were significantly clustered in several high-poverty areas. Controlling for racial/ethnic and income composition and land use, SNAP and WIC vendors were significantly more likely to have exterior (SNAP odds ratio [OR], 2.11; WIC OR, 1.59) and interior (SNAP OR, 3.43; WIC OR, 1.69) tobacco advertisements than other types of tobacco outlets. Conclusion Tobacco advertising is widespread at retail outlets, particularly in low-income and racial/ethnic minority neighborhoods. Policy makers may be able to mitigate the effects of this disparate exposure through tobacco retail licensing, local sign control rules, and SNAP and WIC authorization. PMID:25654220

  17. SNAP-25 is a promising novel cerebrospinal fluid biomarker for synapse degeneration in Alzheimer's disease.

    PubMed

    Brinkmalm, Ann; Brinkmalm, Gunnar; Honer, William G; Frölich, Lutz; Hausner, Lucrezia; Minthon, Lennart; Hansson, Oskar; Wallin, Anders; Zetterberg, Henrik; Blennow, Kaj; Öhrfelt, Annika

    2014-11-23

    Synaptic degeneration is an early pathogenic event in Alzheimer's disease, associated with cognitive impairment and disease progression. Cerebrospinal fluid biomarkers reflecting synaptic integrity would be highly valuable tools to monitor synaptic degeneration directly in patients. We previously showed that synaptic proteins such as synaptotagmin and synaptosomal-associated protein 25 (SNAP-25) could be detected in pooled samples of cerebrospinal fluid, however these assays were not sensitive enough for individual samples. We report a new strategy to study synaptic pathology by using affinity purification and mass spectrometry to measure the levels of the presynaptic protein SNAP-25 in cerebrospinal fluid. By applying this novel affinity mass spectrometry strategy on three separate cohorts of patients, the value of SNAP-25 as a cerebrospinal fluid biomarker for synaptic integrity in Alzheimer's disease was assessed for the first time. We found significantly higher levels of cerebrospinal fluid SNAP-25 fragments in Alzheimer's disease, even in the very early stages, in three separate cohorts. Cerebrospinal fluid SNAP-25 differentiated Alzheimer's disease from controls with area under the curve of 0.901 (P < 0.0001). We developed a sensitive method to analyze SNAP-25 levels in individual CSF samples that to our knowledge was not possible previously. Our results support the notion that synaptic biomarkers may be important tools for early diagnosis, assessment of disease progression, and to monitor drug effects in treatment trials.

  18. Chromophore-assisted laser inactivation of alpha- and gamma-tubulin SNAP-tag fusion proteins inside living cells.

    PubMed

    Keppler, Antje; Ellenberg, Jan

    2009-02-20

    Chromophore-assisted laser inactivation (CALI) can help to unravel localized activities of target proteins at defined times and locations within living cells. Covalent SNAP-tag labeling of fusion proteins with fluorophores such as fluorescein is a fast and highly specific tool to attach the photosensitizer to its target protein in vivo for selective inactivation of the fusion protein. Here, we demonstrate the effectiveness and specificity of SNAP-tag-based CALI by acute inactivation of alpha-tubulin and gamma-tubulin SNAP-tag fusions during live imaging assays of cell division. Singlet oxygen is confirmed as the reactive oxygen species that leads to loss of fusion protein function. The major advantage of SNAP-tag CALI is the ease, reliability, and high flexibility in labeling: the genetically encoded protein tag can be covalently labeled with various dyes matching the experimental requirements. This makes SNAP-tag CALI a very useful tool for rapid inactivation of tagged proteins in living cells.

  19. α-SNAP interferes with the zippering of the SNARE protein membrane fusion machinery.

    PubMed

    Park, Yongsoo; Vennekate, Wensi; Yavuz, Halenur; Preobraschenski, Julia; Hernandez, Javier M; Riedel, Dietmar; Walla, Peter Jomo; Jahn, Reinhard

    2014-06-06

    Neuronal exocytosis is mediated by soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteins. Before fusion, SNARE proteins form complexes bridging the membrane followed by assembly toward the C-terminal membrane anchors, thus initiating membrane fusion. After fusion, the SNARE complex is disassembled by the AAA-ATPase N-ethylmaleimide-sensitive factor that requires the cofactor α-SNAP to first bind to the assembled SNARE complex. Using chromaffin granules and liposomes we now show that α-SNAP on its own interferes with the zippering of membrane-anchored SNARE complexes midway through the zippering reaction, arresting SNAREs in a partially assembled trans-complex and preventing fusion. Intriguingly, the interference does not result in an inhibitory effect on synaptic vesicles, suggesting that membrane properties also influence the final outcome of α-SNAP interference with SNARE zippering. We suggest that binding of α-SNAP to the SNARE complex affects the ability of the SNARE complex to harness energy or transmit force to the membrane. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.

  20. SNAP (Space Nuclear Auxiliary Power) reactor overview. Final report, June 1982-December 1983

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

    Voss, S.S.

    1984-08-01

    The SNAP reactor programs are outlined in this report. A summary of the program is included along with a technical outline of the SER, S2DR, SNAP 10A/SNAPSHOT, S8ER, and S8DR reactor systems. Specifications of the designs, the design logic and a conclusion outlining some of the program weaknesses are given.

  1. Scanning probe acceleration microscopy (SPAM) in fluids: Mapping mechanical properties of surfaces at the nanoscale

    NASA Astrophysics Data System (ADS)

    Legleiter, Justin; Park, Matthew; Cusick, Brian; Kowalewski, Tomasz

    2006-03-01

    One of the major thrusts in proximal probe techniques is combination of imaging capabilities with simultaneous measurements of physical properties. In tapping mode atomic force microscopy (TMAFM), the most straightforward way to accomplish this goal is to reconstruct the time-resolved force interaction between the tip and surface. These tip-sample forces can be used to detect interactions (e.g., binding sites) and map material properties with nanoscale spatial resolution. Here, we describe a previously unreported approach, which we refer to as scanning probe acceleration microscopy (SPAM), in which the TMAFM cantilever acts as an accelerometer to extract tip-sample forces during imaging. This method utilizes the second derivative of the deflection signal to recover the tip acceleration trajectory. The challenge in such an approach is that with real, noisy data, the second derivative of the signal is strongly dominated by the noise. This problem is solved by taking advantage of the fact that most of the information about the deflection trajectory is contained in the higher harmonics, making it possible to filter the signal by “comb” filtering, i.e., by taking its Fourier transform and inverting it while selectively retaining only the intensities at integer harmonic frequencies. Such a comb filtering method works particularly well in fluid TMAFM because of the highly distorted character of the deflection signal. Numerical simulations and in situ TMAFM experiments on supported lipid bilayer patches on mica are reported to demonstrate the validity of this approach.

  2. SNAP 10A ESTIMATED ELECTRICAL CHARACTERISTICS

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

    Cooper, J.C.

    1961-06-01

    The electrical power characteristics of a SNAP 10A converter are estimated for given fractions of power degradation. Graphs are included showing the power characteristics for instantaneous transients from stabilized operation at the maximum efficiency point, and after system temperature stabilization at the operating point. Open-circuit emf's of the converter are estimated for instantaneous and temperature-stabilized cases. (D.L.C.)

  3. The Relationship Between Obesity and Participation in the Supplemental Nutrition Assistance Program (SNAP): Is Mental Health a Mediator?

    PubMed

    Chaparro, M Pia; Harrison, Gail G; Pebley, Anne R; Wang, May

    2014-10-01

    Focusing on adults from the Los Angeles Family and Neighborhood Survey, we investigated whether mental health was a mediator in the association between obesity (body mass index ≥ 30 kg/m 2 ) and participation in the Supplemental Nutrition Assistance Program (SNAP). The analyses included 1776 SNAP participants and eligible nonparticipants. SNAP participants had higher odds of obesity (odds ratio [OR] =2.6; 95% confidence interval [CI], 1.52-4.36) and of reporting a mental health problem (OR = 3.8; 95% CI, 1.68-8.44) than eligible nonparticipants; however, mental health was not a mediator in the association between SNAP participation and obesity. We recommend changes in SNAP to promote healthier food habits among participants and reduce the stress associated with participation.

  4. Quenched substrates for live-cell labeling of SNAP-tagged fusion proteins with improved fluorescent background.

    PubMed

    Stöhr, Katharina; Siegberg, Daniel; Ehrhard, Tanja; Lymperopoulos, Konstantinos; Öz, Simin; Schulmeister, Sonja; Pfeifer, Andrea C; Bachmann, Julie; Klingmüller, Ursula; Sourjik, Victor; Herten, Dirk-Peter

    2010-10-01

    Recent developments in fluorescence microscopy raise the demands for bright and photostable fluorescent tags for specific and background free labeling in living cells. Aside from fluorescent proteins and other tagging methods, labeling of SNAP-tagged proteins has become available thereby increasing the pool of potentially applicable fluorescent dyes for specific labeling of proteins. Here, we report on novel conjugates of benzylguanine (BG) which are quenched in their fluorescence and become highly fluorescent upon labeling of the SNAP-tag, the commercial variant of the human O(6)-alkylguanosyltransferase (hAGT). We identified four conjugates showing a strong increase, i.e., >10-fold, in fluorescence intensity upon labeling of SNAP-tag in vitro. Moreover, we screened a subset of nine BG-dye conjugates in living Escherichia coli and found them all suited for labeling of the SNAP-tag. Here, quenched BG-dye conjugates yield a higher specificity due to reduced contribution from excess conjugate to the fluorescence signal. We further extended the application of these conjugates by labeling a SNAP-tag fusion of the Tar chemoreceptor in live E. coli cells and the eukaryotic transcription factor STAT5b in NIH 3T3 mouse fibroblast cells. Aside from the labeling efficiency and specificity in living cells, we discuss possible mechanisms that might be responsible for the changes in fluorescence emission upon labeling of the SNAP-tag, as well as problems we encountered with nonspecific labeling with certain conjugates in eukaryotic cells.

  5. Evaluating the diagnostic accuracy of Arabic SNAP test for children with hypernasality.

    PubMed

    Abou-Elsaad, Tamer; Afsah, Omayma; Baz, Hemmat; Mansy, Alzahraa

    2016-06-01

    Nasometry is a method of measuring the acoustic correlates of resonance through a computer-based instrument called nasometer. High nasalance scores in comparison to normative data suggest hypernasality and/or other nasality disorders, while low scores suggest hyponasality. Normative values of nasalance for Egyptian Arabic speakers were established using the Arabic SNAP (Simplified Nasometric Assessment Procedures) test. to evaluate the diagnostic accuracy of Arabic SNAP test to allow for its use in the differentiation between normal and hypernasal speech in Egyptian Arabic-speaking children. Nasalance scores of normal children (n=92) on Arabic SNAP test were compared to those of 30 children with velopharyngeal insufficiency due to cleft palate. Receiver operating characteristic (ROC) curve was used to determine cutoff points with the highest sensitivity and specificity. Statistically significant differences were found between both groups for all items in nasometric evaluation (p<0.05) except for prolonged/m/sound (p>0.05). Cutoff points were determined and certain items were selected for routine nasometric evaluation. The Arabic SNAP test is a sensitive and specific tool for evaluation of children with hypernasality and can be used for both diagnosis and follow up of these cases. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  6. Contactless, photoinitiated snap-through in azobenzene-functionalized polymers

    PubMed Central

    Shankar, M. Ravi; Smith, Matthew L.; Tondiglia, Vincent P.; Lee, Kyung Min; McConney, Michael E.; Wang, David H.; Tan, Loon-Seng; White, Timothy J.

    2013-01-01

    Photomechanical effects in polymeric materials and composites transduce light into mechanical work. The ability to control the intensity, polarization, placement, and duration of light irradiation is a distinctive and potentially useful tool to tailor the location, magnitude, and directionality of photogenerated mechanical work. Unfortunately, the work generated from photoresponsive materials is often slow and yields very small power densities, which diminish their potential use in applications. Here, we investigate photoinitiated snap-through in bistable arches formed from samples composed of azobenzene-functionalized polymers (both amorphous polyimides and liquid crystal polymer networks) and report orders-of-magnitude enhancement in actuation rates (approaching 102 mm/s) and powers (as much as 1 kW/m3). The contactless, ultra-fast actuation is observed at irradiation intensities <<100 mW/cm2. Due to the bistability and symmetry of the snap-through, reversible and bidirectional actuation is demonstrated. A model is developed to elucidate the underlying mechanics of the snap-through, specifically focusing on isolating the role of sample geometry, mechanical properties of the materials, and photomechanical strain. Using light to trigger contactless, ultrafast actuation in an otherwise passive structure is a potentially versatile tool to use in mechanical design at the micro-, meso-, and millimeter scales as actuators, as well as switches that can be triggered from large standoff distances, impulse generators for microvehicles, microfluidic valves and mixers in laboratory-on-chip devices, and adaptive optical elements. PMID:24190994

  7. Contactless, photoinitiated snap-through in azobenzene-functionalized polymers.

    PubMed

    Shankar, M Ravi; Smith, Matthew L; Tondiglia, Vincent P; Lee, Kyung Min; McConney, Michael E; Wang, David H; Tan, Loon-Seng; White, Timothy J

    2013-11-19

    Photomechanical effects in polymeric materials and composites transduce light into mechanical work. The ability to control the intensity, polarization, placement, and duration of light irradiation is a distinctive and potentially useful tool to tailor the location, magnitude, and directionality of photogenerated mechanical work. Unfortunately, the work generated from photoresponsive materials is often slow and yields very small power densities, which diminish their potential use in applications. Here, we investigate photoinitiated snap-through in bistable arches formed from samples composed of azobenzene-functionalized polymers (both amorphous polyimides and liquid crystal polymer networks) and report orders-of-magnitude enhancement in actuation rates (approaching 10(2) mm/s) and powers (as much as 1 kW/m(3)). The contactless, ultra-fast actuation is observed at irradiation intensities <100 mW/cm(2). Due to the bistability and symmetry of the snap-through, reversible and bidirectional actuation is demonstrated. A model is developed to elucidate the underlying mechanics of the snap-through, specifically focusing on isolating the role of sample geometry, mechanical properties of the materials, and photomechanical strain. Using light to trigger contactless, ultrafast actuation in an otherwise passive structure is a potentially versatile tool to use in mechanical design at the micro-, meso-, and millimeter scales as actuators, as well as switches that can be triggered from large standoff distances, impulse generators for microvehicles, microfluidic valves and mixers in laboratory-on-chip devices, and adaptive optical elements.

  8. 77 FR 16988 - Protection of Stratospheric Ozone: Amendment to HFO-1234yf SNAP Rule for Motor Vehicle Air...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-23

    ... Protection of Stratospheric Ozone: Amendment to HFO-1234yf SNAP Rule for Motor Vehicle Air Conditioning... hydrofluoroolefin (HFO)-1234yf (2,3,3,3-tetrafluoroprop-1-ene), a substitute for ozone- depleting substances (ODSs... EPA's Stratospheric Ozone Web site at http://www.epa.gov/ozone/snap/regs . The full list of SNAP...

  9. Fiscal Year 1962-63 SNAP 10A Program Proposal (Revised August 15, 1961)

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

    None

    1961-08-15

    The SNAPSHOT program is a joint AEC-USAF effort to flight test SNAP units. SNAPSHOT flights are intended to establish the capabilities of nuclear auxiliary power so that its future use in space systems can be programmed with confidence overcoming both technical and psychological barriers. A set of flight tests for the SNAP 10A system form a part of this effort.

  10. Blocking dephosphorylation at Serine 120 residue in t-SNARE SNAP-23 leads to massive inhibition in exocytosis from mast cells.

    PubMed

    Naskar, Pieu; Naqvi, Nilofer; Puri, Niti

    2018-03-01

    Mast cells (MCs) respond to allergen challenge by release of pre-stored inflammatory mediators from their secretory granules, on cross-linking of Fc(epsilon) receptor I (Fc(epsilon)RI) receptors. The target-SNARE (t-SNARE) SNAP-23 has been shown to play an important role in MC exocytosis and undergoes transient phosphorylation at Serine 95 (S95) and Serine 120 (S120), concomitant with mediator release. During current study we explored the importance of transient nature of phosphorylation at S120 in MC exocytosis. A phosphomimetic SNAP-23-S120D mutant of rodent SNAP-23 was cloned into EGFP vector and its effect on the exocytosis and the mechanisms involved was studied in RBL-2H3 MC line. Secretion reporter assay with SNAP-23-S120D transfected MCs revealed a very significant inhibition of exocytosis, and reduced ruffling in response to Fc(epsilon)RI cross-linking. Further, the effect of this mutation on localization of SNAP-23 in MCs was studied. Immunofluorescence microscopy studies and membrane-cytosol fractionation of green fluorescent protein-tagged SNAP- 23-S120D (GFP-SNAP-23-S120D) transfected MCs showed that a large proportion of GFP-SNAP-23-S120D was residing in cytosol unlike wild-type SNAP-23, in resting and activated MCs and even the membrane associated portion was on internal lysosomal membranes than plasma membrane. These studies imply that dephosphorylation of S120 is important for SNAP-23 membrane association dynamics and subsequently MC degranulation.

  11. On CD-AFM bias related to probe bending

    NASA Astrophysics Data System (ADS)

    Ukraintsev, V. A.; Orji, N. G.; Vorburger, T. V.; Dixson, R. G.; Fu, J.; Silver, R. M.

    2012-03-01

    Critical Dimension AFM (CD-AFM) is a widely used reference metrology. To characterize modern semiconductor devices, very small and flexible probes, often 15 nm to 20 nm in diameter, are now frequently used. Several recent publications have reported on uncontrolled and significant probe-to-probe bias variation during linewidth and sidewall angle measurements [1,2]. Results obtained in this work suggest that probe bending can be on the order of several nanometers and thus potentially can explain much of the observed CD-AFM probe-to-probe bias variation. We have developed and experimentally tested one-dimensional (1D) and two-dimensional (2D) models to describe the bending of cylindrical probes. An earlier 1D bending model reported by Watanabe et al. [3] was refined. Contributions from several new phenomena were considered, including: probe misalignment, diameter variation near the carbon nanotube tip (CNT) apex, probe bending before snapping, distributed van der Waals-London force, etc. The methodology for extraction of the Hamaker probe-surface interaction energy from experimental probe bending data was developed. To overcome limitations of the 1D model, a new 2D distributed force (DF) model was developed. Comparison of the new model with the 1D single point force (SPF) model revealed about 27 % difference in probe bending bias between the two. A simple linear relation between biases predicted by the 1D SPF and 2D DF models was found. This finding simplifies use of the advanced 2D DF model of probe bending in various CD-AFM applications. New 2D and three-dimensional (3D) CDAFM data analysis software is needed to take full advantage of the new bias correction modeling capabilities.

  12. Distal triceps injuries (including snapping triceps): A systematic review of the literature.

    PubMed

    Shuttlewood, Kimberley; Beazley, James; Smith, Christopher D

    2017-06-18

    To review current literature on types of distal triceps injury and determine diagnosis and appropriate management. We performed a systematic review in PubMed, Cochrane and EMBASE using the terms distal triceps tears and snapping triceps on the 10 th January 2017. We excluded all animal, review, foreign language and repeat papers. We reviewed all papers for relevance and of the papers left we were able to establish the types of distal triceps injury, how these injuries are diagnosed and investigated and the types of management of these injuries including surgical. The results are then presented in a review paper format. Three hundred and seventy-nine papers were identified of which 65 were relevant to distal triceps injuries. After exclusion we had 47 appropriate papers. The papers highlighted 2 main distal triceps injuries: Distal triceps tears and snapping triceps. Triceps tear are more common in males than females occurring in the 4 th -5 th decade of life and often due to a direct trauma but are also strongly associated with weightlifting and American football. The tears are diagnosed by history and clinically with a palpable gap. Diagnosis can be confirmed with the use of ultrasound (US) and magnetic resonance imaging. Treatment depends on type of tear. Partial tears can be treated conservatively with bracing and physio whereas acute tears need repair either open or arthroscopic using suture anchor or bone tunnel techniques with similar success. Chronic tears often need augmenting with tendon allograft or autograft. Snapping triceps are also seen more in men than women but at a mean age of 32 years. They are characterized by a snapping sensation mostly medially and can be associated with ulna nerve subluxation and ulna nerve symptoms. US is the diagnostic modality of choice due to its dynamic nature and to differentiate between snapping triceps tendon or ulna nerve. Treatment is conservative initially with activity avoidance and if that fails surgical

  13. Distal triceps injuries (including snapping triceps): A systematic review of the literature

    PubMed Central

    Shuttlewood, Kimberley; Beazley, James; Smith, Christopher D

    2017-01-01

    AIM To review current literature on types of distal triceps injury and determine diagnosis and appropriate management. METHODS We performed a systematic review in PubMed, Cochrane and EMBASE using the terms distal triceps tears and snapping triceps on the 10th January 2017. We excluded all animal, review, foreign language and repeat papers. We reviewed all papers for relevance and of the papers left we were able to establish the types of distal triceps injury, how these injuries are diagnosed and investigated and the types of management of these injuries including surgical. The results are then presented in a review paper format. RESULTS Three hundred and seventy-nine papers were identified of which 65 were relevant to distal triceps injuries. After exclusion we had 47 appropriate papers. The papers highlighted 2 main distal triceps injuries: Distal triceps tears and snapping triceps. Triceps tear are more common in males than females occurring in the 4th-5th decade of life and often due to a direct trauma but are also strongly associated with weightlifting and American football. The tears are diagnosed by history and clinically with a palpable gap. Diagnosis can be confirmed with the use of ultrasound (US) and magnetic resonance imaging. Treatment depends on type of tear. Partial tears can be treated conservatively with bracing and physio whereas acute tears need repair either open or arthroscopic using suture anchor or bone tunnel techniques with similar success. Chronic tears often need augmenting with tendon allograft or autograft. Snapping triceps are also seen more in men than women but at a mean age of 32 years. They are characterized by a snapping sensation mostly medially and can be associated with ulna nerve subluxation and ulna nerve symptoms. US is the diagnostic modality of choice due to its dynamic nature and to differentiate between snapping triceps tendon or ulna nerve. Treatment is conservative initially with activity avoidance and if that fails

  14. The effectiveness of the Stop Now and Plan (SNAP) program for boys at risk for violence and delinquency.

    PubMed

    Burke, Jeffrey D; Loeber, Rolf

    2015-02-01

    Among the available treatments for disruptive behavior problems, a need remains for additional service options to reduce antisocial behavior and prevent further development along delinquent and violent pathways. The Stop Now and Plan (SNAP) Program is an intervention for antisocial behavior among boys between 6 and 11. This paper describes a randomized controlled treatment effectiveness study of SNAP versus standard behavioral health services. The treatment program was delivered to youth with aggressive, rule-breaking, or antisocial behavior in excess of clinical criterion levels. Outcomes were measured at 3, 9, and 15 months from baseline. Youth in the SNAP condition showed significantly greater reduction in aggression, conduct problems, and overall externalizing behavior, as well as counts of oppositional defiant disorder and attention deficit hyperactivity disorder symptoms. Additional benefits for SNAP were observed on measures of depression and anxiety. Further analyses indicated that the SNAP program was more effective among those with a higher severity of initial behavioral problems. At 1 year follow-up, treatment benefits for SNAP were maintained on some outcome measures (aggression, ADHD and ODD, depression and anxiety) but not others. Although overall juvenile justice system contact was not significantly different, youth in SNAP had significantly fewer charges against them relative to those standard services. The SNAP Program, when contrasted with standard services alone, was associated with greater, clinically meaningful, reductions in targeted behaviors. It may be particularly effective for youth with more severe behavioral problems and may result in improvements in internalizing problems as well.

  15. Dismantlement of the TSF-SNAP Reactor Assembly

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

    Peretz, Fred J

    2009-01-01

    This paper describes the dismantlement of the Tower Shielding Facility (TSF)?Systems for Nuclear Auxiliary Power (SNAP) reactor, a SNAP-10A reactor used to validate radiation source terms and shield performance models at Oak Ridge National Laboratory (ORNL) from 1967 through 1973. After shutdown, it was placed in storage at the Y-12 National Security Complex (Y-12), eventually falling under the auspices of the Highly Enriched Uranium (HEU) Disposition Program. To facilitate downblending of the HEU present in the fuel elements, the TSF-SNAP was moved to ORNL on June 24, 2006. The reactor assembly was removed from its packaging, inspected, and the sodium-potassiummore » (NaK) coolant was drained. A superheated steam process was used to chemically react the residual NaK inside the reactor assembly. The heat exchanger assembly was removed from the top of the reactor vessel, and the criticality safety sleeve was exchanged for a new safety sleeve that allowed for the removal of the vessel lid. A chain-mounted tubing cutter was used to separate the lid from the vessel, and the 36 fuel elements were removed and packaged in four U.S. Department of Transportation 2R/6M containers. The fuel elements were returned to Y-12 on July 13, 2006. The return of the fuel elements and disposal of all other reactor materials accomplished the formal objectives of the dismantlement project. In addition, a project model was established for the handling of a fully fueled liquid-metal?cooled reactor assembly. Current criticality safety codes have been benchmarked against experiments performed by Atomics International in the 1950s and 1960s. Execution of this project provides valuable experience applicable to future projects addressing space and liquid-metal-cooled reactors.« less

  16. Multiple functions of the SNARE protein Snap29 in autophagy, endocytic, and exocytic trafficking during epithelial formation in Drosophila.

    PubMed

    Morelli, Elena; Ginefra, Pierpaolo; Mastrodonato, Valeria; Beznoussenko, Galina V; Rusten, Tor Erik; Bilder, David; Stenmark, Harald; Mironov, Alexandre A; Vaccari, Thomas

    2014-01-01

    How autophagic degradation is linked to endosomal trafficking routes is little known. Here we screened a collection of uncharacterized Drosophila mutants affecting membrane transport to identify new genes that also have a role in autophagy. We isolated a loss of function mutant in Snap29 (Synaptosomal-associated protein 29 kDa), the gene encoding the Drosophila homolog of the human protein SNAP29 and have characterized its function in vivo. Snap29 contains 2 soluble NSF attachment protein receptor (SNARE) domains and a asparagine-proline-phenylalanine (NPF motif) at its N terminus and rescue experiments indicate that both SNARE domains are required for function, whereas the NPF motif is in part dispensable. We find that Snap29 interacts with SNARE proteins, localizes to multiple trafficking organelles, and is required for protein trafficking and for proper Golgi apparatus morphology. Developing tissue lacking Snap29 displays distinctive epithelial architecture defects and accumulates large amounts of autophagosomes, highlighting a major role of Snap29 in autophagy and secretion. Mutants for autophagy genes do not display epithelial architecture or secretion defects, suggesting that the these alterations of the Snap29 mutant are unlikely to be caused by the impairment of autophagy. In contrast, we find evidence of elevated levels of hop-Stat92E (hopscotch-signal transducer and activator of transcription protein at 92E) ligand, receptor, and associated signaling, which might underlie the epithelial defects. In summary, our findings support a role of Snap29 at key steps of membrane trafficking, and predict that signaling defects may contribute to the pathogenesis of cerebral dysgenesis, neuropathy, ichthyosis, and palmoplantar keratoderma (CEDNIK), a human congenital syndrome due to loss of Snap29.

  17. Snap-buckling in asymmetrically constrained elastic strips

    NASA Astrophysics Data System (ADS)

    Sano, Tomohiko G.; Wada, Hirofumi

    2018-01-01

    When a flat elastic strip is compressed along its axis, it is bent in one of two possible directions via spontaneous symmetry breaking, forming a cylindrical arc. This is a phenomenon well known as Euler buckling. When this cylindrical section is pushed in the other direction, the bending direction can suddenly reverse. This instability is called "snap-through buckling" and is one of the elementary shape transitions in a prestressed thin structure. Combining experiments and theory, we study snap-buckling of an elastic strip with one end hinged and the other end clamped. These asymmetric boundary constraints break the intrinsic symmetry of the strip, generating mechanical behaviors, including largely hysteretic but reproducible force responses and switchlike discontinuous shape changes. We establish the set of exact analytical solutions to fully explain all our major experimental and numerical findings. Asymmetric boundary conditions arise naturally in diverse situations when a thin object is in contact with a solid surface at one end. The introduction of asymmetry through boundary conditions yields new insight into complex and programmable functionalities in material and industrial design.

  18. Questions and Answers About SNAP Alternatives in Each Sector

    EPA Pesticide Factsheets

    The following list of questions and answers provides an overview of the regulations governing the use of substitutes that are reviewed under the Significant New Alternatives Policy (SNAP) program in various industrial sectors.

  19. Select putative neurodevelopmental toxins modify SNAP-25 expression in primary cultures of rat cerebellar granule cells.

    PubMed

    Zieminska, Elzbieta; Lenart, Jacek; Lazarewicz, Jerzy W

    2016-08-31

    A presynaptic protein SNAP-25 belonging to SNARE complex which is instrumental in intracellular vesicular trafficking and exocytosis, has been implicated in hyperactivity and cognitive abilities in some neuropsychiatric disorders. The unclear etiology of the behavior disrupting neurodevelopmental disabilities in addition to genetic causes most likely involves environmental factors. The aim of this in vitro study was to test if various suspected developmental neurotoxins can alter SNAP-25 mRNA and protein expression in neurons. Real-time PCR and Western blotting analyses were used to assess SNAP-25 mRNA and protein levels in primary cultures of rat cerebellar granule cells (CGCs). The test substances: tetrabromobisphenol-A (TBBPA), thimerosal (TH), silver nanoparticles (NAg), valproic acid (VPA) and thalidomide (THAL), were administered to CGC cultures at subtoxic concentrations for 24h. The results demonstrated that SNAP-25 mRNA levels were increased by 49 and 66% by TBBPA and THAL, respectively, whereas VPA and NAg reduced these levels to 48 and 64% of the control, respectively. The SNAP-25 protein content in CGCs was increased by 79% by TBBPA, 25% by THAL and 21% by NAg; VPA and TH reduced these levels to 73 and 69% of the control, respectively. The variety of changes in SNAP-25 expression on mRNA and protein level suggests the diversity of the mechanism of action of the test substances. This initial study provided no data on concentration-effect relations and on functional changes in CGCs. However it is the first to demonstrate the effect of different compounds that are suspected of causing neurodevelopmental disabilities on SNAP-25 expression. These results suggest that this protein may be a common target for not only inherited but also environmental modifications linked to behavioral deficits in neurodevelopmental disabilities. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  20. A Biomechanical Comparison of the Long Snap in Football Between High School and University Football Players.

    PubMed

    Chizewski, Michael G; Alexander, Marion J L

    2015-08-01

    Limited previous research was located that examined the technique of the long snap in football. The purpose of the study was to compare the joint movements, joint velocities, and body positions used to perform fast and accurate long snaps in high school (HS) and university (UNI) athletes. Ten HS and 10 UNI subjects were recruited for filming, each performing 10 snaps at a target with the fastest and most accurate trial being selected for subject analysis. Eighty-three variables were measured using Dartfish Team Pro 4.5.2 video analysis software, with statistical analysis performed using Microsoft Excel and SPSS 16.0. Several significant comparisons to long snapping technique between groups were noted during analysis; however, the body position and movement variables at release showed the greatest number of significant differences. The UNI athletes demonstrated significantly higher release velocity and left elbow extension velocity, with significantly lower release height and release angle than the HS group. Total snap time (release time + total flight time) was determined to have the strongest correlation to release velocity for the HS group (r = -0.915) and UNI group (r = -0.918). The study suggests HS long snappers may benefit from less elbow flexion and more knee flexion in the backswing (set position) to increase release velocity. University long snappers may benefit from increased left elbow extension range of motion during force production and decreased shoulder flexion at critical instant to increase long snap release velocity.

  1. SNAP-8 power conversion system design review

    NASA Technical Reports Server (NTRS)

    Lopez, L. P.

    1970-01-01

    The conceptual design of the SNAP-8 electrical generating system configurations are reviewed including the evolution of the PCS configuration, and the current concepts. The reliabilities of two alternative PCS-G heat rejection loop configurations with two radiator design concepts are also reviewed. A computer program for calculating system pressure loss using multiple-loop flow analysis is included.

  2. A Simple Snap Oscillator with Coexisting Attractors, Its Time-Delayed Form, Physical Realization, and Communication Designs

    NASA Astrophysics Data System (ADS)

    Rajagopal, Karthikeyan; Jafari, Sajad; Akgul, Akif; Karthikeyan, Anitha; Çiçek, Serdar; Shekofteh, Yasser

    2018-05-01

    In this paper, we report a novel chaotic snap oscillator with one nonlinear function. Dynamic analysis of the system shows the existence of bistability. To study the time delay effects on the proposed snap oscillator, we introduce multiple time delay in the fourth state equation. Investigation of dynamical properties of the time-delayed system shows that the snap oscillator exhibits the same multistable properties as the nondelayed system. The new multistable hyperjerk chaotic system has been tested in chaos shift keying and symmetric choc shift keying modulated communication designs for engineering applications. It has been determined that the symmetric chaos shift keying modulated communication system implemented with the new chaotic system is more successful than the chaos shift keying modulation for secure communication. Also, circuit implementation of the chaotic snap oscillator with tangent function is carried out showing its feasibility.

  3. Creating a Minnesota Statewide SNAP-Ed Program Evaluation

    ERIC Educational Resources Information Center

    Gold, Abby; Barno, Trina Adler; Sherman, Shelley; Lovett, Kathleen; Hurtado, G. Ali

    2013-01-01

    Systematic evaluation is an essential tool for understanding program effectiveness. This article describes the pilot test of a statewide evaluation tool for the Supplemental Nutrition Assistance Program-Education (SNAP-Ed). A computer algorithm helped Community Nutrition Educators (CNEs) build surveys specific to their varied educational settings…

  4. NREL Engineers Look for a Cool Way to Make AC Units an Affordable Snap |

    Science.gov Websites

    installing the components of the EcoSnap-AC. Photo by Dennis Schroeder Engineers Chuck Booten and Jon Winkler Booten drills a hole in the wall to mount the EcoSnap-AC. Photo by Dennis Schroeder The Evolution of an , and eliminating air leaks and water intrusion. Photo by Dennis Schroeder Looking Ahead to a Cooler

  5. Habitat Suitability Index Models: Snapping turtle

    USGS Publications Warehouse

    Graves, Brent M.; Anderson, Stanley H.

    1987-01-01

    A review and synthesis of existing information were used to develop a Habitat Suitability Index (HSI) model for the snapping turtle (Chelydra serpentina). The model consolidates habitat use information into a framework appropriate for field application, and is scaled to produce an index between 0.0 (unsuitable habitat) and 1.0 (optimum habitat). HSI models are designed to be used with Habitat Evaluation Procedures previously developed by the U.S. Fish and Wildlife Service.

  6. Associations between food insecurity, supplemental nutrition assistance program (SNAP) benefits, and body mass index among adult females.

    PubMed

    Jilcott, Stephanie B; Wall-Bassett, Elizabeth D; Burke, Sloane C; Moore, Justin B

    2011-11-01

    Obesity disproportionately affects low-income and minority individuals and has been linked with food insecurity, particularly among women. More research is needed to examine potential mechanisms linking obesity and food insecurity. Therefore, this study's purpose was to examine cross-sectional associations between food insecurity, Supplemental Nutrition Assistance Program (SNAP) benefits per household member, perceived stress, and body mass index (BMI) among female SNAP participants in eastern North Carolina (n=202). Women were recruited from the Pitt County Department of Social Services between October 2009 and April 2010. Household food insecurity was measured using the validated US Department of Agriculture 18-item food security survey module. Perceived stress was measured using the 14-item Cohen's Perceived Stress Scale. SNAP benefits and number of children in the household were self-reported and used to calculate benefits per household member. BMI was calculated from measured height and weight (as kg/m(2)). Multivariate linear regression was used to examine associations between BMI, SNAP benefits, stress, and food insecurity while adjusting for age and physical activity. In adjusted linear regression analyses, perceived stress was positively related to food insecurity (P<0.0001), even when SNAP benefits were included in the model. BMI was positively associated with food insecurity (P=0.04). Mean BMI was significantly greater among women receiving <$150 in SNAP benefits per household member vs those receiving ≥$150 in benefits per household member (35.8 vs 33.1; P=0.04). Results suggest that provision of adequate SNAP benefits per household member might partially ameliorate the negative effects of food insecurity on BMI. Copyright © 2011 American Dietetic Association. Published by Elsevier Inc. All rights reserved.

  7. The Schedule for Nonadaptive and Adaptive Personality for Youth (SNAP-Y): a new measure for assessing adolescent personality and personality pathology.

    PubMed

    Linde, Jennifer A; Stringer, Deborah; Simms, Leonard J; Clark, Lee Anna

    2013-08-01

    The Schedule for Nonadaptive and Adaptive Personality-Youth Version (SNAP-Y) is a new, reliable self-report questionnaire that assesses 15 personality traits relevant to both normal-range personality and the alternative DSM-5 model for personality disorder. Community adolescents, 12 to 18 years old (N = 364), completed the SNAP-Y; 347 also completed the Big Five Inventory-Adolescent, 144 provided 2-week retest data, and 128 others completed the Minnesota Multiphasic Personality Inventory-Adolescent. Outpatient adolescents (N = 103) completed the SNAP-Y, and 97 also completed the Minnesota Multiphasic Personality Inventory-Adolescent. The SNAP-Y demonstrated strong psychometric properties, and structural, convergent, discriminant, and external validities. Consistent with the continuity of personality, results paralleled those in adult and college samples using the adult Schedule for Nonadaptive and Adaptive Personality-Second Edition (SNAP-2), from which the SNAP-Y derives and which has established validity in personality-trait assessment across the normal-abnormal continuum. The SNAP-Y thus provides a new, clinically useful instrument to assess personality traits and personality pathology in adolescents.

  8. Maternal Rest/Nrsf Regulates Zebrafish Behavior through snap25a/b

    PubMed Central

    Moravec, Cara E.; Samuel, John; Weng, Wei; Wood, Ian C.

    2016-01-01

    During embryonic development, regulation of gene expression is key to creating the many subtypes of cells that an organism needs throughout its lifetime. Recent work has shown that maternal genetics and environmental factors have lifelong consequences on diverse processes ranging from immune function to stress responses. The RE1-silencing transcription factor (Rest) is a transcriptional repressor that interacts with chromatin-modifying complexes to repress transcription of neural-specific genes during early development. Here we show that in zebrafish, maternally supplied rest regulates expression of target genes during larval development and has lifelong impacts on behavior. Larvae deprived of maternal rest are hyperactive and show atypical spatial preferences. Adult male fish deprived of maternal rest present with atypical spatial preferences in a novel environment assay. Transcriptome sequencing revealed 158 genes that are repressed by maternal rest in blastula stage embryos. Furthermore, we found that maternal rest is required for target gene repression until at least 6 dpf. Importantly, disruption of the RE1 sites in either snap25a or snap25b resulted in behaviors that recapitulate the hyperactivity phenotype caused by absence of maternal rest. Both maternal rest mutants and snap25a RE1 site mutants have altered primary motor neuron architecture that may account for the enhanced locomotor activity. These results demonstrate that maternal rest represses snap25a/b to modulate larval behavior and that early Rest activity has lifelong behavioral impacts. SIGNIFICANCE STATEMENT Maternal factors deposited in the oocyte have well-established roles during embryonic development. We show that, in zebrafish, maternal rest (RE1-silencing transcription factor) regulates expression of target genes during larval development and has lifelong impacts on behavior. The Rest transcriptional repressor interacts with chromatin-modifying complexes to limit transcription of neural

  9. Laser-pump/X-ray-probe experiments with electrons ejected from a Cu(111) target: space-charge acceleration.

    PubMed

    Schiwietz, G; Kühn, D; Föhlisch, A; Holldack, K; Kachel, T; Pontius, N

    2016-09-01

    A comprehensive investigation of the emission characteristics for electrons induced by X-rays of a few hundred eV at grazing-incidence angles on an atomically clean Cu(111) sample during laser excitation is presented. Electron energy spectra due to intense infrared laser irradiation are investigated at the BESSY II slicing facility. Furthermore, the influence of the corresponding high degree of target excitation (high peak current of photoemission) on the properties of Auger and photoelectrons liberated by a probe X-ray beam is investigated in time-resolved pump and probe measurements. Strong electron energy shifts have been found and assigned to space-charge acceleration. The variation of the shift with laser power and electron energy is investigated and discussed on the basis of experimental as well as new theoretical results.

  10. Long-Term Nitric Oxide Release and Elevated Temperature Stability with S-Nitroso-N-acetylpenicillamine (SNAP)-Doped Elast-eon E2As Polymer

    PubMed Central

    Brisbois, Elizabeth J.; Handa, Hitesh; Major, Terry C.; Bartlett, Robert H.; Meyerhoff, Mark E.

    2013-01-01

    Nitric oxide (NO) is known to be a potent inhibitor of platelet activation and adhesion. Healthy endothelial cells that line the inner walls of all blood vessels exhibit a NO flux of 0.5~4×10−10 mol cm−2 min−1 that helps prevent thrombosis. Materials with a NO flux that is equivalent to this level are expected to exhibit similar anti-thrombotic properties. In this study, five biomedical grade polymers doped with S-nitroso-N-acetylpenicillamine (SNAP) were investigated for their potential to control the release of NO from the SNAP within the polymers, and further control the release of SNAP itself. SNAP in the Elast-eon E2As polymer creates an inexpensive, homogeneous coating that can locally deliver NO (via thermal and photochemical reactions) as well slowly release SNAP. Furthermore, SNAP is surprisingly stable in the E2As polymer, retaining 82% of the initial SNAP after 2 months storage at 37°C. The E2As polymer containing SNAP was coated on the walls of extracorporeal circuits (ECC) and exposed to 4 h blood flow in a rabbit model of extracorporeal circulation to examine the effects on platelet count, platelet function, clot area, and fibrinogen adsorption. After 4 h, platelet count was preserved at 100±7% of baseline for the SNAP/E2As coated loops, compared to 60±6% for E2As control circuits (n=4). The SNAP/E2As coating also reduced the thrombus area when compared to the control (2.3±0.6 and 3.4±1.1 pixels/cm2, respectively). The results suggest that the new SNAP/E2As coating has potential to improve the thromboresistance of intravascular catheters, grafts, and other blood contacting medical devices, and exhibits excellent storage stability compared to previously reported NO release polymeric materials. PMID:23777908

  11. Severe Nuclear Accident Program (SNAP) - a real time model for accidental releases

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

    Saltbones, J.; Foss, A.; Bartnicki, J.

    1996-12-31

    The model: Several Nuclear Accident Program (SNAP) has been developed at the Norwegian Meteorological Institute (DNMI) in Oslo to provide decision makers and Government officials with real-time tool for simulating large accidental releases of radioactivity from nuclear power plants or other sources. SNAP is developed in the Lagrangian framework in which atmospheric transport of radioactive pollutants is simulated by emitting a large number of particles from the source. The main advantage of the Lagrangian approach is a possibility of precise parameterization of advection processes, especially close to the source. SNAP can be used to predict the transport and deposition ofmore » a radioactive cloud in e future (up to 48 hours, in the present version) or to analyze the behavior of the cloud in the past. It is also possible to run the model in the mixed mode (partly analysis and partly forecast). In the routine run we assume unit (1 g s{sup -1}) emission in each of three classes. This assumption is very convenient for the main user of the model output in case of emergency: Norwegian Radiation Protection Agency. Due to linearity of the model equations, user can test different emission scenarios as a post processing task by assigning different weights to concentration and deposition fields corresponding to each of three emission classes. SNAP is fully operational and can be run by the meteorologist on duty at any time. The output from SNAP has two forms: First on the maps of Europe, or selected parts of Europe, individual particles are shown during the simulation period. Second, immediately after the simulation, concentration/deposition fields can be shown every three hours of the simulation period as isoline maps for each emission class. In addition, concentration and deposition maps, as well as some meteorological data, are stored on a public accessible disk for further processing by the model users.« less

  12. A Brief Description of the Kokkos implementation of the SNAP potential in ExaMiniMD.

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

    Thompson, Aidan P.; Trott, Christian Robert

    2017-11-01

    Within the EXAALT project, the SNAP [1] approach is being used to develop high accuracy potentials for use in large-scale long-time molecular dynamics simulations of materials behavior. In particular, we have developed a new SNAP potential that is suitable for describing the interplay between helium atoms and vacancies in high-temperature tungsten[2]. This model is now being used to study plasma-surface interactions in nuclear fusion reactors for energy production. The high-accuracy of SNAP potentials comes at the price of increased computational cost per atom and increased computational complexity. The increased cost is mitigated by improvements in strong scaling that can bemore » achieved using advanced algorithms [3].« less

  13. The running athlete: stress fractures, osteitis pubis, and snapping hips.

    PubMed

    Henning, P Troy

    2014-03-01

    Pelvic stress fractures, osteitis pubis, and snapping hip syndrome account for a portion of the overuse injuries that can occur in the running athlete. PUBMED SEARCHES WERE PERFORMED FOR EACH ENTITY USING THE FOLLOWING KEYWORDS: snapping hip syndrome, coxa sultans, pelvic stress fracture, and osteitis pubis from 2008 to 2013. Topic reviews, case reports, case series, and randomized trials were included for review. Clinical review. Level 4. Collectively, 188 articles were identified. Of these, 58 were included in this review. Based on the available evidence, the majority of these overuse injuries can be managed non-operatively. Primary treatment should include removal from offending activity, normalizing regional muscle strength/length imbalances and nutritional deficiencies, and mitigating training errors through proper education of the athlete and training staff. C.

  14. The SNAP Platform: Social Networking for Academic Purposes

    ERIC Educational Resources Information Center

    Kirkwood, Keith

    2010-01-01

    Purpose: This paper aims to introduce an enterprise-wide Web 2.0 learning support platform--SNAP, developed at Victoria University in Melbourne, Australia. Design/methodology/approach: Pointing to the evolution of the social web, the paper discusses the potential for the development of e-learning platforms that employ constructivist, connectivist,…

  15. Reconceiving SNAP: Is Nutritional Assistance Really Income Support?

    ERIC Educational Resources Information Center

    Besharov, Douglas J.

    2016-01-01

    Since its creation, the Supplemental Nutrition Assistance Program (SNAP) has changed from an antihunger program to an income-supplementation program. Because the program (and its predecessor Food Stamp Program) was not designed for this purpose, the result is a program that has many unintended and, many believe, negative effects. The key challenge…

  16. 8-Nitro-cGMP Attenuates the Interaction between SNARE Complex and Complexin through S-Guanylation of SNAP-25.

    PubMed

    Kishimoto, Yusuke; Kunieda, Kohei; Kitamura, Atsushi; Kakihana, Yuki; Akaike, Takaaki; Ihara, Hideshi

    2018-02-21

    8-Nitroguanosine 3',5'-cyclic monophosphate (8-nitro-cGMP) is the second messenger in nitric oxide/reactive oxygen species redox signaling. This molecule covalently binds to protein thiol groups, called S-guanylation, and exerts various biological functions. Recently, we have identified synaptosomal-associated protein 25 (SNAP-25) as a target of S-guanylation, and demonstrated that S-guanylation of SNAP25 enhanced SNARE complex formation. In this study, we have examined the effects of S-guanylation of SNAP-25 on the interaction between the SNARE complex and complexin (cplx), which binds to the SNARE complex with a high affinity. Pull-down assays and coimmunoprecipitation experiments have revealed that S-guanylation of Cys90 in SNAP-25 attenuates the interaction between the SNARE complex and cplx. In addition, blue native-PAGE followed by Western blot analysis revealed that the amount of cplx detected at a high molecular weight decreased upon 8-nitro-cGMP treatment in SH-SY5Y cells. These results demonstrated for the first time that S-guanylation of SNAP-25 attenuates the interaction between the SNARE complex and cplx.

  17. Small peptides patterned after the N-terminus domain of SNAP25 inhibit SNARE complex assembly and regulated exocytosis.

    PubMed

    Blanes-Mira, Clara; Merino, Jaime M; Valera, Elvira; Fernández-Ballester, Gregorio; Gutiérrez, Luis M; Viniegra, Salvador; Pérez-Payá, Enrique; Ferrer-Montiel, Antonio

    2004-01-01

    Synthetic peptides patterned after the C-terminus of synaptosomal associated protein of 25 kDa (SNAP25) efficiently abrogate regulated exocytosis. In contrast, the use of SNAP25 N-terminal-derived peptides to modulate SNAP receptors (SNARE) complex assembly and neurosecretion has not been explored. Here, we show that the N-terminus of SNAP25, specially the segment that encompasses 22Ala-44Ile, is essential for the formation of the SNARE complex. Peptides patterned after this protein domain are potent inhibitors of SNARE complex formation. The inhibitory activity correlated with their propensity to adopt an alpha-helical secondary structure. These peptides abrogated SNARE complex formation only when added previous to the onset of aggregate assembly. Analysis of the mechanism of action revealed that these peptides disrupted the binary complex formed by SNAP25 and syntaxin. The identified peptides inhibited Ca2+-dependent exocytosis from detergent-permeabilized excitable cells. Noteworthy, these amino acid sequences markedly protected intact hippocampal neurones against hypoglycaemia-induced, glutamate-mediated excitotoxicity with a potency that rivalled that displayed by botulinum neurotoxins. Our findings indicate that peptides patterned after the N-terminus of SNAP25 are potent inhibitors of SNARE complex formation and neuronal exocytosis. Because of their activity in intact neurones, these cell permeable peptides may be hits for antispasmodic and analgesic drug development.

  18. A Multilevel Functional Study of a SNAP25 At-Risk Variant for Bipolar Disorder and Schizophrenia.

    PubMed

    Houenou, Josselin; Boisgontier, Jennifer; Henrion, Annabelle; d'Albis, Marc-Antoine; Dumaine, Anne; Linke, Julia; Wessa, Michèle; Daban, Claire; Hamdani, Nora; Delavest, Marine; Llorca, Pierre-Michel; Lançon, Christophe; Schürhoff, Franck; Szöke, Andrei; Le Corvoisier, Philippe; Barau, Caroline; Poupon, Cyril; Etain, Bruno; Leboyer, Marion; Jamain, Stéphane

    2017-10-25

    The synaptosomal-associated protein SNAP25 is a key player in synaptic vesicle docking and fusion and has been associated with multiple psychiatric conditions, including schizophrenia, bipolar disorder, and attention-deficit/hyperactivity disorder. We recently identified a promoter variant in SNAP25 , rs6039769 , that is associated with early-onset bipolar disorder and a higher gene expression level in human prefrontal cortex. In the current study, we showed that this variant was associated both in males and females with schizophrenia in two independent cohorts. We then combined in vitro and in vivo approaches in humans to understand the functional impact of the at-risk allele. Thus, we showed in vitro that the rs6039769 C allele was sufficient to increase the SNAP25 transcription level. In a postmortem expression analysis of 33 individuals affected with schizophrenia and 30 unaffected control subjects, we showed that the SNAP25b / SNAP25a ratio was increased in schizophrenic patients carrying the rs6039769 at-risk allele. Last, using genetics imaging in a cohort of 71 subjects, we showed that male risk carriers had an increased amygdala-ventromedial prefrontal cortex functional connectivity and a larger amygdala than non-risk carriers. The latter association has been replicated in an independent cohort of 121 independent subjects. Altogether, results from these multilevel functional studies are bringing strong evidence for the functional consequences of this allelic variation of SNAP25 on modulating the development and plasticity of the prefrontal-limbic network, which therefore may increase the vulnerability to both early-onset bipolar disorder and schizophrenia. SIGNIFICANCE STATEMENT Functional characterization of disease-associated variants is a key challenge in understanding neuropsychiatric disorders and will open an avenue in the development of personalized treatments. Recent studies have accumulated evidence that the SNARE complex, and more specifically

  19. STATISTICAL ANALYSIS OF SNAP 10A THERMOELECTRIC CONVERTER ELEMENT PROCESS DEVELOPMENT VARIABLES

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

    Fitch, S.H.; Morris, J.W.

    1962-12-15

    Statistical analysis, primarily analysis of variance, was applied to evaluate several factors involved in the development of suitable fabrication and processing techniques for the production of lead telluride thermoelectric elements for the SNAP 10A energy conversion system. The analysis methods are described as to their application for determining the effects of various processing steps, estabIishing the value of individual operations, and evaluating the significance of test results. The elimination of unnecessary or detrimental processing steps was accomplished and the number of required tests was substantially reduced by application of these statistical methods to the SNAP 10A production development effort. (auth)

  20. SnapDock—template-based docking by Geometric Hashing

    PubMed Central

    Estrin, Michael; Wolfson, Haim J.

    2017-01-01

    Abstract Motivation: A highly efficient template-based protein–protein docking algorithm, nicknamed SnapDock, is presented. It employs a Geometric Hashing-based structural alignment scheme to align the target proteins to the interfaces of non-redundant protein–protein interface libraries. Docking of a pair of proteins utilizing the 22 600 interface PIFACE library is performed in < 2 min on the average. A flexible version of the algorithm allowing hinge motion in one of the proteins is presented as well. Results: To evaluate the performance of the algorithm a blind re-modelling of 3547 PDB complexes, which have been uploaded after the PIFACE publication has been performed with success ratio of about 35%. Interestingly, a similar experiment with the template free PatchDock docking algorithm yielded a success rate of about 23% with roughly 1/3 of the solutions different from those of SnapDock. Consequently, the combination of the two methods gave a 42% success ratio. Availability and implementation: A web server of the application is under development. Contact: michaelestrin@gmail.com or wolfson@tau.ac.il PMID:28881968

  1. Palisade endings in extraocular eye muscles revealed by SNAP-25 immunoreactivity.

    PubMed

    Eberhorn, Andreas C; Horn, Anja K E; Eberhorn, Nicola; Fischer, Petra; Boergen, Klaus-Peter; Büttner-Ennever, Jean A

    2005-03-01

    Palisade endings form a cuff of nerve terminals around the tip of muscle fibres. They are found only in extraocular muscles, but no definite evidence for their role in eye movements has been established. Palisade endings have been reported in all species so far investigated except the rat. In this study we demonstrate that antibodies against SNAP-25, the synaptosomal associated protein of 25 kDa, reliably visualize the complete motor, sensory and autonomic innervation of the extraocular muscles in human, monkey and rat. The SNAP-25 antibody can be combined with other immunofluorescence procedures, and is used here to study properties of palisade endings. With SNAP-25 immunolabelling putative palisade endings are identified in the rat for the first time. They are not well branched, but fulfil several criteria of palisade endings, being associated with non-twitch fibres as shown by double labelling with 'myosin heavy chain slow-twitch' antibodies. The putative palisade endings of the rat lack alpha-bungarotoxin binding, which implies that these synapses are sensory. If palisade endings are sensory then they could function as an eye muscle proprioceptor. They seem to be a general feature of all vertebrate eye muscles, unlike the other two extraocular proprioceptors, muscle spindles and Golgi tendon organs, the presence of which varies widely between species.

  2. Distributed force probe bending model of critical dimension atomic force microscopy bias

    NASA Astrophysics Data System (ADS)

    Ukraintsev, Vladimir A.; Orji, Ndubuisi G.; Vorburger, Theodore V.; Dixson, Ronald G.; Fu, Joseph; Silver, Rick M.

    2013-04-01

    Critical dimension atomic force microscopy (CD-AFM) is a widely used reference metrology technique. To characterize modern semiconductor devices, small and flexible probes, often 15 to 20 nm in diameter, are used. Recent studies have reported uncontrolled and significant probe-to-probe bias variation during linewidth and sidewall angle measurements. To understand the source of these variations, tip-sample interactions between high aspect ratio features and small flexible probes, and their influence on measurement bias, should be carefully studied. Using theoretical and experimental procedures, one-dimensional (1-D) and two-dimensional (2-D) models of cylindrical probe bending relevant to carbon nanotube (CNT) AFM probes were developed and tested. An earlier 1-D bending model was refined, and a new 2-D distributed force (DF) model was developed. Contributions from several factors were considered, including: probe misalignment, CNT tip apex diameter variation, probe bending before snapping, and distributed van der Waals-London force. A method for extracting Hamaker probe-surface interaction energy from experimental probe-bending data was developed. Comparison of the new 2-D model with 1-D single point force (SPF) model revealed a difference of about 28% in probe bending. A simple linear relation between biases predicted by the 1-D SPF and 2-D DF models was found. The results suggest that probe bending can be on the order of several nanometers and can partially explain the observed CD-AFM probe-to-probe variation. New 2-D and three-dimensional CD-AFM data analysis software is needed to take full advantage of the new bias correction modeling capabilities.

  3. Multi-environment selection of small sieve snap beans reduces production constraints in East Africa and subtropical regions

    USDA-ARS?s Scientific Manuscript database

    Common bean rust caused by Uromyces appendiculatus, and heat stress lower the yield and quality of snap beans (Phaseolus vulgaris L.) in East Africa. Four snap bean breeding lines previously selected for broad-spectrum rust resistance (involving Ur-4 and Ur-11 rust genes) and heat tolerance followin...

  4. SnapShot: Phosphoregulation of Mitosis.

    PubMed

    Burgess, Andrew; Vuong, Jenny; Rogers, Samuel; Malumbres, Marcos; O'Donoghue, Seán I

    2017-06-15

    During mitosis, a cell divides its duplicated genome into two identical daughter cells. This process must occur without errors to prevent proliferative diseases (e.g., cancer). A key mechanism controlling mitosis is the precise timing of more than 32,000 phosphorylation and dephosphorylation events by a network of kinases and counterbalancing phosphatases. The identity, magnitude, and temporal regulation of these events have emerged recently, largely from advances in mass spectrometry. Here, we show phosphoevents currently believed to be key regulators of mitosis. For an animated version of this SnapShot, please see http://www.cell.com/cell/enhanced/odonoghue2. Copyright © 2017. Published by Elsevier Inc.

  5. A qualitative study of diverse experts' views about barriers and strategies to improve the diets and health of Supplemental Nutrition Assistance Program (SNAP) beneficiaries.

    PubMed

    Leung, Cindy W; Hoffnagle, Elena E; Lindsay, Ana C; Lofink, Hayley E; Hoffman, Vanessa A; Turrell, Sophie; Willett, Walter C; Blumenthal, Susan J

    2013-01-01

    The Supplemental Nutrition Assistance Program (SNAP), the largest federal food assistance program, currently serves 44.7 million Americans with a budget of $75 billion in 2011. This study engaged leading experts for in-depth, semi-structured interviews to explore their opinions concerning the existing challenges and barriers to eating nutritiously in SNAP. Experts also proposed strategies for improving nutritional status among SNAP recipients. Twenty-seven individuals were interviewed from advocacy, government, industry, and research organizations. Interviews were recorded, transcribed, coded, and analyzed for thematic content. The high cost of nutrient-rich foods, inadequate SNAP benefits, limited access to purchasing healthy foods, and environmental factors associated with poverty were identified as barriers that influence nutrition among low-income households in the United States. Six themes emerged among respondents from diverse sectors about how to address these challenges, including providing SNAP participants with incentives to purchase nutrient-rich food consistent with the 2010 Dietary Guidelines for Americans, restricting the purchase of nutrient-poor foods and beverages with program benefits, modifying the frequency of SNAP benefit distribution, enhancing nutrition education, improving the SNAP retailer environment, and increasing state and federal level coordination and consistency of program implementation. Given the recent dramatic increase in SNAP enrollment, policymakers must address existing barriers as well as consider new strategies to improve nutrition policies in SNAP so that the program can continue to address food insecurity needs as well as provide a healthful diet for SNAP beneficiaries. Copyright © 2013 Academy of Nutrition and Dietetics. Published by Elsevier Inc. All rights reserved.

  6. A Qualitative Study of Diverse Experts’ Views About Barriers and Strategies to Improve the Diets and Health of Supplemental Nutrition Assistance Program (SNAP) Beneficiaries

    PubMed Central

    Leung, Cindy W.; Hoffnagle, Elena E.; Lindsay, Ana C.; Lofink, Hayley E.; Hoffman, Vanessa A.; Turrell, Sophie; Willett, Walter C.; Blumenthal, Susan J.

    2012-01-01

    The Supplemental Nutrition Assistance Program (SNAP), the largest federal food assistance program, currently serves 44.7 million Americans with a budget of $75 billion in 2011. This study engaged leading experts for in-depth, semi-structured interviews to explore their opinions concerning the existing challenges and barriers to eating nutritiously in SNAP. Experts also proposed strategies for improving nutritional status among SNAP recipients. Twenty-seven individuals were interviewed from advocacy, government, industry, and research organizations. Interviews were recorded, transcribed, coded and analyzed for thematic content. The high cost of nutrient-rich foods, inadequate SNAP benefits, limited access to purchasing healthy foods, and environmental factors associated with poverty were identified as barriers that influence nutrition among low-income households in the United States. Six themes emerged among respondents from diverse sectors about how to address these challenges including: 1) providing SNAP participants with incentives to purchase nutrient-rich food consistent with the 2010 Dietary Guidelines for Americans; 2) restricting the purchase of nutrient-poor foods and beverages with program benefits; 3) modifying the frequency of SNAP benefit distribution; 4) enhancing nutrition education; 5) improving the SNAP retailer environment and 6) increasing state and federal level coordination and consistency of program implementation. Given the recent dramatic increase in SNAP enrollment, policymakers must address existing barriers as well as consider new strategies to improve nutrition policies in SNAP so that the program can continue to address food insecurity needs as well as provide a healthful diet for SNAP beneficiaries. PMID:23260725

  7. SnapShot: Fanconi anemia and associated proteins.

    PubMed

    Wang, Anderson T; Smogorzewska, Agata

    2015-01-15

    Fanconi anemia is a genetic disorder resulting from biallelic mutations in one of the 17 FANC genes. It is characterized by congenital abnormalities, bone marrow failure, and cancer predisposition. The underlying cause is genomic instability resulting from the deficiency in replication-dependent DNA interstrand crosslink repair pathway commonly referred to as the Fanconi anemia-BRCA pathway. This SnapShot presents the key factors involved. Copyright © 2015 Elsevier Inc. All rights reserved.

  8. Evaluation of a Wake Vortex Upset Model Based on Simultaneous Measurements of Wake Velocities and Probe-Aircraft Accelerations

    NASA Technical Reports Server (NTRS)

    Short, B. J.; Jacobsen, R. A.

    1979-01-01

    Simultaneous measurements were made of the upset responses experienced and the wake velocities encountered by an instrumented Learjet probe aircraft behind a Boeing 747 vortex-generating aircraft. The vortex-induced angular accelerations experienced could be predicted within 30% by a mathematical upset response model when the characteristics of the wake were well represented by the vortex model. The vortex model used in the present study adequately represented the wake flow field when the vortices dissipated symmetrically and only one vortex pair existed in the wake.

  9. The Radiation Belt Storm Probes (RBSP) Energetic Particle, Composition, and Thermal plasma (ECT) Suite: Upcoming Opportunties for Testing Radiation Belt Acceleration Mechanisms

    NASA Astrophysics Data System (ADS)

    Spence, Harlan; Reeves, Geoffrey

    2012-07-01

    The Radiation Belt Storm Probes (RBSP) mission will launch in late summer 2012 and begin its exploration of acceleration and dynamics of energetic particles in the inner magnetosphere. In this presentation, we discuss opportunities afforded by the RBSP Energetic Particle, Composition, and Thermal plasma (ECT) instrument suite to advance our understanding of acceleration processes in the radiation belts. The RBSP-ECT instrument suite comprehensively measures the electron and major ion populations of the inner magnetosphere, from the lowest thermal plasmas of the plasmasphere, to the hot plasma of the ring current, to the relativistic populations of the radiation belts. Collectively, the ECT measurements will reveal the complex cross-energy coupling of these colocated particle populations, which along with concurrent RBSP wave measurements, will permit various wave-particle acceleration mechanisms to be tested. We review the measurement capabilities of the RBSP-ECT instrument suite, and demonstrate several examples of how these measurements will be used to explore candidate acceleration mechanisms and dynamics of radiation belt particles.

  10. Reflective Polyethylene Mulch Reduces Mexican Bean Beetle (Coleoptera: Coccinellidae) Densities and Damage in Snap Beans.

    PubMed

    Nottingham, L B; Kuhar, T P

    2016-08-01

    Mexican bean beetle, Epilachna varivestis Mulsant, is a serious pest of snap beans, Phaseolus vulgaris L., in the eastern United States. These beetles are intolerant to direct sunlight, explaining why individuals are typically found on the undersides of leaves and in the lower portion of the plant canopy. We hypothesized that snap beans grown on reflective, agricultural polyethylene (plastic mulch) would have fewer Mexican bean beetles and less injury than those grown on black plastic or bare soil. In 2014 and 2015, beans were seeded into beds of metallized, white, and black plastic, and bare soil, in field plots near Blacksburg, VA. Mexican bean beetle density, feeding injury, predatory arthropods, and snap bean yield were sampled. Reflected light intensity, temperature, and humidity were monitored using data loggers. Pyranometer readings showed that reflected light intensity was highest over metallized plastic and second highest over white plastic; black plastic and bare soil were similarly low. Temperature and humidity were unaffected by treatments. Significant reductions in Mexican bean beetle densities and feeding injury were observed in both metallized and white plastic plots compared to black plastic and bare soil, with metallized plastic having the fewest Mexican bean beetle life stages and injury. Predatory arthropod densities were not reduced by reflective plastic. Metallized plots produced the highest yields, followed by white. The results of this study suggest that growing snap beans on reflective plastic mulch can suppress the incidence and damage of Mexican bean beetle, and increase yield in snap beans. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  11. Opportunities for future supernova studies of cosmic acceleration.

    PubMed

    Weller, J; Albrecht, A

    2001-03-05

    We investigate the potential of a future supernova data set, as might be obtained by the proposed SNAP satellite, to discriminate among different "dark energy" theories that describe an accelerating Universe. We find that many such models can be distinguished with a fit to the effective pressure-to-density ratio w of this energy. More models can be distinguished when the effective slope dw/dz of a changing w is also fit, but only if our knowledge of the current mass density Omega(m) is improved. We investigate the use of "fitting functions" to interpret luminosity distance data from supernova searches.

  12. Palisade endings in extraocular eye muscles revealed by SNAP-25 immunoreactivity

    PubMed Central

    Eberhorn, Andreas C; Horn, Anja KE; Eberhorn, Nicola; Fischer, Petra; Boergen, Klaus-Peter; Büttner-Ennever, Jean A

    2005-01-01

    Palisade endings form a cuff of nerve terminals around the tip of muscle fibres. They are found only in extraocular muscles, but no definite evidence for their role in eye movements has been established. Palisade endings have been reported in all species so far investigated except the rat. In this study we demonstrate that antibodies against SNAP-25, the synaptosomal associated protein of 25 kDa, reliably visualize the complete motor, sensory and autonomic innervation of the extraocular muscles in human, monkey and rat. The SNAP-25 antibody can be combined with other immunofluorescence procedures, and is used here to study properties of palisade endings. With SNAP-25 immunolabelling putative palisade endings are identified in the rat for the first time. They are not well branched, but fulfil several criteria of palisade endings, being associated with non-twitch fibres as shown by double labelling with ‘myosin heavy chain slow-twitch’ antibodies. The putative palisade endings of the rat lack α-bungarotoxin binding, which implies that these synapses are sensory. If palisade endings are sensory then they could function as an eye muscle proprioceptor. They seem to be a general feature of all vertebrate eye muscles, unlike the other two extraocular proprioceptors, muscle spindles and Golgi tendon organs, the presence of which varies widely between species. PMID:15733303

  13. The research and development program for the SNAP dark energy experiment

    NASA Astrophysics Data System (ADS)

    Levi, Michael E.

    2007-03-01

    The SNAP mission includes two surveys to study dark energy. In the deep survey, we detect more than 2000 matched Type Ia supernovae within a 7.5 deg2 field, with redshifts covering the range z=0.1 1.7. This uniform and high-quality set of “standard candles” will provide the most precise mapping of the expansion of the universe through the magnitude-redshift relation (Hubble diagram) ever constructed. The SNAP wide survey maps 1000 deg2/year in nine passbands to 28th magnitude. A weak-lensing study of the wide survey data traces the growth of structure and provides completely independent constraints on dark energy parameters. SNAP utilizes a 2 m class rigid light-weight telescope with a three-mirror anastigmatic design for a large, diffraction-limited field of view. The telescope feeds an instrumented ˜0.7 deg2 focal plane with ˜600 million pixels sensitive to wavelengths from 400 to 1700 nm. Full-depletion, high-purity silicon CCDs detect visible wavelengths, and 1700 nm cutoff HgCdTe detector arrays detect the near-IR. Passive cooling of the focal plane, fixed solar panels, fixed filters, and fixed antenna for telemetry simplify the mission. Room temperature operation of the telescope facilitates preflight testing. The satellite is placed in orbit about the second Earth Sun Lagrange point (L2).

  14. SnapAnatomy, a computer-based interactive tool for independent learning of human anatomy.

    PubMed

    Yip, George W; Rajendran, Kanagasuntheram

    2008-06-01

    Computer-aided instruction materials are becoming increasing popular in medical education and particularly in the teaching of human anatomy. This paper describes SnapAnatomy, a new interactive program that the authors designed for independent learning of anatomy. SnapAnatomy is primarily tailored for the beginner student to encourage the learning of anatomy by developing a three-dimensional visualization of human structure that is essential to applications in clinical practice and the understanding of function. The program allows the student to take apart and to accurately put together body components in an interactive, self-paced and variable manner to achieve the learning outcome.

  15. SnapShot: Hormones of the gastrointestinal tract.

    PubMed

    Coate, Katie C; Kliewer, Steven A; Mangelsdorf, David J

    2014-12-04

    Specialized endocrine cells secrete a variety of peptide hormones all along the gastrointestinal (GI) tract, making it one of the largest endocrine organs in the body. Nutrients and developmental and neural cues trigger the secretion of gastrointestinal (GI) hormones from specialized endocrine cells along the GI tract. These hormones act in target tissues to facilitate digestion and regulate energy homeostasis. This SnapShot summarizes the production and functions of GI hormones. Copyright © 2014 Elsevier Inc. All rights reserved.

  16. Implementation of Wireless Terminals at Farmers’ Markets: Impact on SNAP Redemption and Overall Sales

    PubMed Central

    Bertmann, Farryl M. W.; Ohri-Vachaspati, Punam; Buman, Matthew P.

    2012-01-01

    Although farmers’ markets offer healthy foods for purchase, many lack the equipment necessary to process convenient, card-based transactions. We assessed the impact of providing wireless terminals to 5 markets on overall sales and redemption of Supplemental Nutrition Assistance Program (SNAP) benefits. Sales increased significantly at 4 of the 5 markets after implementation of the terminals, and overall sales increased above and beyond SNAP redemption alone. Implementation of wireless terminals may be important for improving the financial stability and accessibility of farmers’ markets. PMID:22594725

  17. SNAP dendrimers: multivalent protein display on dendrimer-like DNA for directed evolution.

    PubMed

    Kaltenbach, Miriam; Stein, Viktor; Hollfelder, Florian

    2011-09-19

    Display systems connect a protein with the DNA encoding it. Such systems (e.g., phage or ribosome display) have found widespread application in the directed evolution of protein binders and constitute a key element of the biotechnological toolkit. In this proof-of-concept study we describe the construction of a system that allows the display of multiple copies of a protein of interest in order to take advantage of avidity effects during affinity panning. To this end, dendrimer-like DNA is used as a scaffold with docking points that can join the coding DNA with multiple protein copies. Each DNA construct is compartmentalised in water-in-oil emulsion droplets. The corresponding protein is expressed, in vitro, inside the droplets as a SNAP-tag fusion. The covalent bond between DNA and the SNAP-tag is created by reaction with dendrimer-bound benzylguanine (BG). The ability to form dendrimer-like DNA straightforwardly from oligonucleotides bearing BG allowed the comparison of a series of templates differing in size, valency and position of BG. In model selections the most efficient constructs show recoveries of up to 0.86 % and up to 400-fold enrichments. The comparison of mono- and multivalent constructs suggests that the avidity effect enhances enrichment by up to fivefold and recovery by up to 25-fold. Our data establish a multivalent format for SNAP-display based on dendrimer-like DNA as the first in vitro display system with defined tailor-made valencies and explore a new application for DNA nanostructures. These data suggest that multivalent SNAP dendrimers have the potential to facilitate the selection of protein binders especially during early rounds of directed evolution, allowing a larger diversity of candidate binders to be recovered. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. 40 CFR 82.180 - Agency review of SNAP submissions.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... until EPA has received data it judges adequate to support analysis of the submission. (4) Letter of... time the Agency perceives a lack of information necessary to reach a SNAP determination, it will... expires even if the Agency fails to reach a decision within the 90-day review period or fails to...

  19. Different mechanics of snap-trapping in the two closely related carnivorous plants Dionaea muscipula and Aldrovanda vesiculosa

    NASA Astrophysics Data System (ADS)

    Poppinga, Simon; Joyeux, Marc

    2011-10-01

    The carnivorous aquatic waterwheel plant (Aldrovanda vesiculosa L.) and the closely related terrestrial venus flytrap (Dionaea muscipula Sol. ex J. Ellis) both feature elaborate snap-traps, which shut after reception of an external mechanical stimulus by prey animals. Traditionally, Aldrovanda is considered as a miniature, aquatic Dionaea, an assumption which was already established by Charles Darwin. However, videos of snapping traps from both species suggest completely different closure mechanisms. Indeed, the well-described snapping mechanism in Dionaea comprises abrupt curvature inversion of the two trap lobes, while the closing movement in Aldrovanda involves deformation of the trap midrib but not of the lobes, which do not change curvature. In this paper, we present detailed mechanical models for these plants, which are based on the theory of thin solid membranes and explain this difference by showing that the fast snapping of Aldrovanda is due to kinematic amplification of the bending deformation of the midrib, while that of Dionaea unambiguously relies on the buckling instability that affects the two lobes.

  20. Testing Two Alternative Pathological Personality Measures in the Assessment of Psychopathy: An Examination of the Snap and DAPP-BQ.

    PubMed

    Pryor, Lauren R; Miller, Joshua D; Gaughan, Eric T

    2009-02-01

    The current study examined the interrelations between two measures of pathological personality, the Schedule for Nonadaptive and Adaptive Personality (SNAP; Clark, 1993) and the Dimensional Assessment of Personality Pathology-Basic Questionnaire (DAPP-BQ; Livesley, 1990), and their respective relations with psychopathy. Two hundred and twenty-nine undergraduate students completed the SNAP, DAPP-BQ, and two self-report psychopathy inventories, the Levenson Self-Report Psychopathy Scale (LSRP; Levenson, Kiehl, & Fitzpatrick, 1995) and the Psychopathic Personality Inventory-Revised (PPI-R; Lilienfeld & Widows, 2005). Results revealed good convergence between conceptually related SNAP and DAPP-BQ subscales. Both the SNAP and DAPP-BQ accounted for a substantial amount of variance in psychopathy scores although the DAPP-BQ accounted for a larger percentage of the variance and demonstrated greater incremental validity. Results suggest that both measures can be successfully used to assess traits associated with psychopathy.

  1. Interstellar Mapping and Acceleration Probe (IMAP)

    NASA Astrophysics Data System (ADS)

    Schwadron, Nathan

    2016-04-01

    Our piece of cosmic real-estate, the heliosphere, is the domain of all human existence - an astrophysical case-history of the successful evolution of life in a habitable system. By exploring our global heliosphere and its myriad interactions, we develop key physical knowledge of the interstellar interactions that influence exoplanetary habitability as well as the distant history and destiny of our solar system and world. IBEX was the first mission to explore the global heliosphere and in concert with Voyager 1 and Voyager 2 is discovering a fundamentally new and uncharted physical domain of the outer heliosphere. In parallel, Cassini/INCA maps the global heliosphere at energies (~5-55 KeV) above those measured by IBEX. The enigmatic IBEX ribbon and the INCA belt were unanticipated discoveries demonstrating that much of what we know or think we understand about the outer heliosphere needs to be revised. The next quantum leap enabled by IMAP will open new windows on the frontier of Heliophysics at a time when the space environment is rapidly evolving. IMAP with 100 times the combined resolution and sensitivity of IBEX and INCA will discover the substructure of the IBEX ribbon and will reveal in unprecedented resolution global maps of our heliosphere. The remarkable synergy between IMAP, Voyager 1 and Voyager 2 will remain for at least the next decade as Voyager 1 pushes further into the interstellar domain and Voyager 2 moves through the heliosheath. The "A" in IMAP refers to acceleration of energetic particles. With its combination of highly sensitive pickup and suprathermal ion sensors, IMAP will provide the species and spectral coverage as well as unprecedented temporal resolution to associate emerging suprathermal tails with interplanetary structures and discover underlying physical acceleration processes. These key measurements will provide what has been a critical missing piece of suprathermal seed particles in our understanding of particle acceleration to high

  2. Septin 7 reduces nonmuscle myosin IIA activity in the SNAP23 complex and hinders GLUT4 storage vesicle docking and fusion

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

    Wasik, Anita A.; Dumont, Vincent; Tienari, Jukka

    Glomerular epithelial cells, podocytes, are insulin responsive and can develop insulin resistance. Here, we demonstrate that the small GTPase septin 7 forms a complex with nonmuscle myosin heavy chain IIA (NMHC-IIA; encoded by MYH9), a component of the nonmuscle myosin IIA (NM-IIA) hexameric complex. We observed that knockdown of NMHC-IIA decreases insulin-stimulated glucose uptake into podocytes. Both septin 7 and NM-IIA associate with SNAP23, a SNARE protein involved in GLUT4 storage vesicle (GSV) docking and fusion with the plasma membrane. We observed that insulin decreases the level of septin 7 and increases the activity of NM-IIA in the SNAP23 complex,more » as visualized by increased phosphorylation of myosin regulatory light chain. Also knockdown of septin 7 increases the activity of NM-IIA in the complex. The activity of NM-IIA is increased in diabetic rat glomeruli and cultured human podocytes exposed to macroalbuminuric sera from patients with type 1 diabetes. Collectively, the data suggest that the activity of NM-IIA in the SNAP23 complex plays a key role in insulin-stimulated glucose uptake into podocytes. Furthermore, we observed that septin 7 reduces the activity of NM-IIA in the SNAP23 complex and thereby hinders GSV docking and fusion with the plasma membrane. - Highlights: • Septin 7, nonmuscle myosin heavy chain IIA (NMHC-IIA) and SNAP23 form a complex. • Knockdown of septin 7 increases NM-IIA activity in the SNAP23 complex. • Insulin decreases septin 7 level and increases NM-IIA activity in the SNAP23 complex. • Septin 7 hinders GSV docking/fusion by reducing NM-IIA activity in the SNAP23 complex.« less

  3. Morphological study on the olfactory systems of the snapping turtle, Chelydra serpentina.

    PubMed

    Nakamuta, Nobuaki; Nakamuta, Shoko; Kato, Hideaki; Yamamoto, Yoshio

    2016-06-01

    In this study, the olfactory system of a semi-aquatic turtle, the snapping turtle, has been morphologically investigated by electron microscopy, immunohistochemistry, and lectin histochemistry. The nasal cavity of snapping turtle was divided into the upper and lower chambers, lined by the sensory epithelium containing ciliated and non-ciliated olfactory receptor neurons, respectively. Each neuron expressed both Gαolf, the α-subunit of G-proteins coupling to the odorant receptors, and Gαo, the α-subunit of G-proteins coupling to the type 2 vomeronasal receptors. The axons originating from the upper chamber epithelium projected to the ventral part of the olfactory bulb, while those from the lower chamber epithelium to the dorsal part of the olfactory bulb. Despite the identical expression of G-protein α-subunits in the olfactory receptor neurons, these two projections were clearly distinguished from each other by the differential expression of glycoconjugates. In conclusion, these data indicate the presence of two types of olfactory systems in the snapping turtle. Topographic arrangement of the upper and lower chambers and lack of the associated glands in the lower chamber epithelium suggest their possible involvement in the detection of odorants: upper chamber epithelium in the air and the lower chamber epithelium in the water. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. A Reliability Improvement Program Planning Report for the SNAP 10A Space Nuclear Power Unit

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

    Coombs, M. G.; Smith, C. K.; Wilson, L. A.

    1961-03-14

    The estimated achieved reliability of SNAP 10A space nuclear power units will be relatively low at the timeof the first SNAPSHOT flight test in April 1963 and the existing R&D program does not provide a significant reliabiity growth thereafter. The total costs of an 8-satellite network using SNAP 10A units over a 5-year period has been approximated for the case where the total cost of a single satellite launched is 8 million dollars.

  5. SNAP: A computer program for generating symbolic network functions

    NASA Technical Reports Server (NTRS)

    Lin, P. M.; Alderson, G. E.

    1970-01-01

    The computer program SNAP (symbolic network analysis program) generates symbolic network functions for networks containing R, L, and C type elements and all four types of controlled sources. The program is efficient with respect to program storage and execution time. A discussion of the basic algorithms is presented, together with user's and programmer's guides.

  6. SNAP-8 refractory boiler development program

    NASA Technical Reports Server (NTRS)

    Fuller, R. A.

    1974-01-01

    Performance and endurance tests of the SNAP-8, SN-1 refractory metal boiler are described. The tests were successful and indicated that the boiler heat transfer area could be reduced significantly primarily because of the wetting characteristics of mercury on tantalum in a contaminant-free environment. A continuous endurance test of more than 10,000 hours was conducted without noticeable change in the thermal performance of the boiler. A conclusion of the metallographic examination of the boiler following the endurance test was that expected boiler life would be of the order of 40,000 hours at observed corrosion rates.

  7. Weak Lensing from Space I: Instrumentation and Survey Strategy

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

    Rhodes, Jason; Refregier, Alexandre; Massey, Richard

    A wide field space-based imaging telescope is necessary to fully exploit the technique of observing dark matter via weak gravitational lensing. This first paper in a three part series outlines the survey strategies and relevant instrumental parameters for such a mission. As a concrete example of hardware design, we consider the proposed Supernova/Acceleration Probe (SNAP). Using SNAP engineering models, we quantify the major contributions to this telescope's Point Spread Function (PSF). These PSF contributions are relevant to any similar wide field space telescope. We further show that the PSF of SNAP or a similar telescope will be smaller than currentmore » ground-based PSFs, and more isotropic and stable over time than the PSF of the Hubble Space Telescope. We outline survey strategies for two different regimes - a ''wide'' 300 square degree survey and a ''deep'' 15 square degree survey that will accomplish various weak lensing goals including statistical studies and dark matter mapping.« less

  8. SNAP/SHOT Your Ability to Support That Next Application.

    ERIC Educational Resources Information Center

    Jones, Ernest L.

    SNAP/SHOT (System Network Analysis Program-Simulated Host Overview Technique) is a discrete simulation of a network and/or host model available through IBM at the Raleigh System Center. The simulator provides an analysis of a total IBM Communications System. Input data must be obtained from RMF, SMF, and the CICS Analyzer to determine the existing…

  9. An essential and NSF independent role for α-SNAP in store-operated calcium entry.

    PubMed

    Miao, Yong; Miner, Cathrine; Zhang, Lei; Hanson, Phyllis I; Dani, Adish; Vig, Monika

    2013-07-16

    Store-operated calcium entry (SOCE) by calcium release activated calcium (CRAC) channels constitutes a primary route of calcium entry in most cells. Orai1 forms the pore subunit of CRAC channels and Stim1 is the endoplasmic reticulum (ER) resident Ca(2+) sensor. Upon store-depletion, Stim1 translocates to domains of ER adjacent to the plasma membrane where it interacts with and clusters Orai1 hexamers to form the CRAC channel complex. Molecular steps enabling activation of SOCE via CRAC channel clusters remain incompletely defined. Here we identify an essential role of α-SNAP in mediating functional coupling of Stim1 and Orai1 molecules to activate SOCE. This role for α-SNAP is direct and independent of its known activity in NSF dependent SNARE complex disassembly. Importantly, Stim1-Orai1 clustering still occurs in the absence of α-SNAP but its inability to support SOCE reveals that a previously unsuspected molecular re-arrangement within CRAC channel clusters is necessary for SOCE. DOI:http://dx.doi.org/10.7554/eLife.00802.001.

  10. Polycyclic aromatic hydrocarbons affect survival and development of common snapping turtle (Chelydra serpentina) embryos and hatchlings.

    PubMed

    Van Meter, Robin J; Spotila, James R; Avery, Harold W

    2006-08-01

    Polycyclic aromatic hydrocarbons (PAHs) are toxic compounds found in the John Heinz National Wildlife Refuge in Philadelphia, Pennsylvania. We assessed the impact of PAHs and crude oil on snapping turtle development and behavior by exposing snapping turtle eggs from the Refuge and from three clean reference sites to individual PAHs or a crude oil mixture at stage 9 of embryonic development. Exposure to PAHs had a significant effect on survival rates in embryos from one clean reference site, but not in embryos from the other sites. There was a positive linear relationship between level of exposure to PAHs and severity of deformities in embryos collected from two of the clean reference sites. Neither righting response nor upper temperature tolerance (critical thermal maximum, CTM) of snapping turtle hatchlings with no or minor deformities was significantly affected by exposure to PAHs.

  11. SnapShot: Visualization to Propel Ice Hockey Analytics.

    PubMed

    Pileggi, H; Stolper, C D; Boyle, J M; Stasko, J T

    2012-12-01

    Sports analysts live in a world of dynamic games flattened into tables of numbers, divorced from the rinks, pitches, and courts where they were generated. Currently, these professional analysts use R, Stata, SAS, and other statistical software packages for uncovering insights from game data. Quantitative sports consultants seek a competitive advantage both for their clients and for themselves as analytics becomes increasingly valued by teams, clubs, and squads. In order for the information visualization community to support the members of this blossoming industry, it must recognize where and how visualization can enhance the existing analytical workflow. In this paper, we identify three primary stages of today's sports analyst's routine where visualization can be beneficially integrated: 1) exploring a dataspace; 2) sharing hypotheses with internal colleagues; and 3) communicating findings to stakeholders.Working closely with professional ice hockey analysts, we designed and built SnapShot, a system to integrate visualization into the hockey intelligence gathering process. SnapShot employs a variety of information visualization techniques to display shot data, yet given the importance of a specific hockey statistic, shot length, we introduce a technique, the radial heat map. Through a user study, we received encouraging feedback from several professional analysts, both independent consultants and professional team personnel.

  12. Synaptosomal-associated protein 25 (Snap-25) gene polymorphism frequency in fibromyalgia syndrome and relationship with clinical symptoms.

    PubMed

    Balkarli, Ayse; Sengül, Cem; Tepeli, Emre; Balkarli, Huseyin; Cobankara, Veli

    2014-05-31

    SNAP-25 protein is contributory to plasma membrane and synaptic vesicle fusions that are critical points in neurotransmission. SNAP-25 gene is associated with behavioral symptoms, personality and psychological disorders. In addition, SNAP-25 protein can be related to different neurotransmitter functions due to its association with vesicle membrane transition and fusion. This is important because neurologic, cognitive, and psychologic disorders in fibromyalgia syndrome (FMS) can be related to this function. This relationship may be enlightening for etiopathogenesis of FMS and treatment approaches. We aimed to study a SNAP-25 gene polymorphism, which is related to many psychiatric diseases, and FMS association in this prospective study. We included 71 patients who were diagnosed according to new criteria and 57 matched healthy women in this study. Both groups were evaluated regarding age, height, weight, BMI, education level, marital and occupational status. A new diagnosis of FMS was made from criteria scoring, SF-36, Beck depression scale, and VAS that were applied to the patient group. SNAP-25 gene polymorphism and disease activity score correlations were compared. Mean age was 38±5,196 and 38.12±4.939 in patient and control groups, respectively (p=0.542). No significant difference was found between groups regarding age, height, weight, BMI, education level, marital or occupational status (p > 0.05). Ddel T/C genotype was significantly higher in the patient group (p = 0.009). MnlI gene polymorphism did not show a correlation with any score whereas a significant correlation was found between Ddel T/C genotype and Beck depression scale and VAS score (p < 0.05). FMS etiopathogenesis is not clearly known. Numerous neurologic, cognitive and psychological disorders were found during studies looking at cause. Our study showed increased SNAP-25 Ddel T/C genotype in FMS patients compared to the control group, which is related to behavioral symptoms, personality and

  13. Dynamic Snap-Through of Thin-Walled Structures by a Reduced Order Method

    NASA Technical Reports Server (NTRS)

    Przekop, Adam; Rizzi, Stephen A.

    2006-01-01

    The goal of this investigation is to further develop nonlinear modal numerical simulation methods for application to geometrically nonlinear response of structures exposed to combined high intensity random pressure fluctuations and thermal loadings. The study is conducted on a flat aluminum beam, which permits a comparison of results obtained by a reduced-order analysis with those obtained from a numerically intensive simulation in physical degrees-of-freedom. A uniformly distributed thermal loading is first applied to investigate the dynamic instability associated with thermal buckling. A uniformly distributed random loading is added to investigate the combined thermal-acoustic response. In the latter case, three types of response characteristics are considered, namely: (i) small amplitude vibration around one of the two stable buckling equilibrium positions, (ii) intermittent snap-through response between the two equilibrium positions, and (iii) persistent snap-through response between the two equilibrium positions. For the reduced order analysis, four categories of modal basis functions are identified including those having symmetric transverse (ST), anti-symmetric transverse (AT), symmetric in-plane (SI), and anti-symmetric in-plane (AI) displacements. The effect of basis selection on the quality of results is investigated for the dynamic thermal buckling and combined thermal-acoustic response. It is found that despite symmetric geometry, loading, and boundary conditions, the AT and SI modes must be included in the basis as they participate in the snap-through behavior.

  14. Dynamic Snap-Through of Thermally Buckled Structures by a Reduced Order Method

    NASA Technical Reports Server (NTRS)

    Przekop, Adam; Rizzi, Stephen A.

    2007-01-01

    The goal of this investigation is to further develop nonlinear modal numerical simulation methods for application to geometrically nonlinear response of structures exposed to combined high intensity random pressure fluctuations and thermal loadings. The study is conducted on a flat aluminum beam, which permits a comparison of results obtained by a reduced-order analysis with those obtained from a numerically intensive simulation in physical degrees-of-freedom. A uniformly distributed thermal loading is first applied to investigate the dynamic instability associated with thermal buckling. A uniformly distributed random loading is added to investigate the combined thermal-acoustic response. In the latter case, three types of response characteristics are considered, namely: (i) small amplitude vibration around one of the two stable buckling equilibrium positions, (ii) intermittent snap-through response between the two equilibrium positions, and (iii) persistent snap-through response between the two equilibrium positions. For the reduced-order analysis, four categories of modal basis functions are identified including those having symmetric transverse, anti-symmetric transverse, symmetric in-plane, and anti-symmetric in-plane displacements. The effect of basis selection on the quality of results is investigated for the dynamic thermal buckling and combined thermal-acoustic response. It is found that despite symmetric geometry, loading, and boundary conditions, the anti-symmetric transverse and symmetric in-plane modes must be included in the basis as they participate in the snap-through behavior.

  15. Reduction of Thrombosis and Bacterial Infection via Controlled Nitric Oxide (NO) Release from S-Nitroso-N-acetylpenicillamine (SNAP) Impregnated CarboSil Intravascular Catheters

    PubMed Central

    2017-01-01

    Nitric oxide (NO) has many important physiological functions, including its ability to inhibit platelet activation and serve as potent antimicrobial agent. The multiple roles of NO in vivo have led to great interest in the development of biomaterials that can deliver NO for specific biomedical applications. Herein, we report a simple solvent impregnation technique to incorporate a nontoxic NO donor, S-nitroso-N-acetylpenicillamine (SNAP), into a more biocompatible biomedical grade polymer, CarboSil 20 80A. The resulting polymer-crystal composite material yields a very stable, long-term NO release biomaterial. The SNAP impregnation process is carefully characterized and optimized, and it is shown that SNAP crystal formation occurs in the bulk of the polymer after solvent evaporation. LC-MS results demonstrate that more than 70% of NO release from this new composite material originates from the SNAP embedded CarboSil phase, and not from the SNAP species leaching out into the soaking solution. Catheters prepared with CarboSil and then impregnated with 15 wt % SNAP provide a controlled NO release over a 14 d period at physiologically relevant fluxes and are shown to significantly reduce long-term (14 day) bacterial biofilm formation against Staphylococcus epidermidis and Pseudonomas aeruginosa in a CDC bioreactor model. After 7 h of catheter implantation in the jugular veins of rabbit, the SNAP CarboSil catheters exhibit a 96% reduction in thrombus area (0.03 ± 0.01 cm2/catheter) compared to the controls (0.84 ± 0.19 cm2/catheter) (n = 3). These results suggest that SNAP impregnated CarboSil can become an attractive new biomaterial for use in preparing intravascular catheters and other implanted medical devices. PMID:28317023

  16. Bubble snap-off and capillary-back pressure during counter-current spontaneous imbibition into model pores.

    PubMed

    Unsal, Evren; Mason, Geoffrey; Morrow, Norman R; Ruth, Douglas W

    2009-04-09

    A previous paper (Unsal, E.; Mason, G.; Ruth, D. W.; Morrow, N. R. J. Colloid Interface Sci. 2007, 315, 200-209) reported experiments involving counter-current spontaneous imbibition into a model pore system consisting of a rod in an angled slot covered by a glass plate. Such an arrangement gives two tubes with different cross-sections (both size and shape) with an interconnection through the gap between the rod and the plate. In the previous experiments, the wetting phase advanced in the small tube and nonwetting phase retreated in the large tube. No bubbles were formed. In this paper, we study experimentally and theoretically the formation of bubbles at the open end of the large tube and their subsequent snap-off. Such bubbles reduce the capillary back pressure produced by the larger tube and can thus have an effect on the local rate of imbibition. In the model pore system, the rod was either in contact with the glass, forming two independent tubes, or the rod was spaced from the glass to allow cross-flow between the tubes. For small gaps, there were three distinct menisci. The one with the highest curvature was between the rod and the plate. The next most highly curved was in the smaller tube, and the least highly curved meniscus was in the large tube and this was the tube from which the bubbles developed. The pressure in the dead end of the system was recorded during imbibition. Once the bubble starts to form outside of the tube, the pressure drops rapidly and then steadies. After the bubble snaps off, the pressure rises to almost the initial value and stays essentially constant until the next bubble starts to form. After snap-off, the meniscus in the large tube appears to invade the large tube for some distance. The snap-off is the result of capillary instability; it takes place significantly inside the large tube with flow of wetting phase moving in the angular corners. As imbibition into the small tube progresses, the rate of imbibition decreases and the

  17. A SNAP-Tagged Derivative of HIV-1—A Versatile Tool to Study Virus-Cell Interactions

    PubMed Central

    Eckhardt, Manon; Anders, Maria; Muranyi, Walter; Heilemann, Mike; Krijnse-Locker, Jacomine; Müller, Barbara

    2011-01-01

    Fluorescently labeled human immunodeficiency virus (HIV) derivatives, combined with the use of advanced fluorescence microscopy techniques, allow the direct visualization of dynamic events and individual steps in the viral life cycle. HIV proteins tagged with fluorescent proteins (FPs) have been successfully used for live-cell imaging analyses of HIV-cell interactions. However, FPs display limitations with respect to their physicochemical properties, and their maturation kinetics. Furthermore, several independent FP-tagged constructs have to be cloned and characterized in order to obtain spectral variations suitable for multi-color imaging setups. In contrast, the so-called SNAP-tag represents a genetically encoded non-fluorescent tag which mediates specific covalent coupling to fluorescent substrate molecules in a self-labeling reaction. Fusion of the SNAP-tag to the protein of interest allows specific labeling of the fusion protein with a variety of synthetic dyes, thereby offering enhanced flexibility for fluorescence imaging approaches. Here we describe the construction and characterization of the HIV derivative HIVSNAP, which carries the SNAP-tag as an additional domain within the viral structural polyprotein Gag. Introduction of the tag close to the C-terminus of the matrix domain of Gag did not interfere with particle assembly, release or proteolytic virus maturation. The modified virions were infectious and could be propagated in tissue culture, albeit with reduced replication capacity. Insertion of the SNAP domain within Gag allowed specific staining of the viral polyprotein in the context of virus producing cells using a SNAP reactive dye as well as the visualization of individual virions and viral budding sites by stochastic optical reconstruction microscopy. Thus, HIVSNAP represents a versatile tool which expands the possibilities for the analysis of HIV-cell interactions using live cell imaging and sub-diffraction fluorescence microscopy. PMID:21799764

  18. Characteristics of Supplemental Nutrition Assistance Program Households: Fiscal Year 2012. Nutrition Assistance Program Report Series. No. SNAP-14-CHAR

    ERIC Educational Resources Information Center

    Gray, Kelsey Farson; Eslami, Esa

    2014-01-01

    The Supplemental Nutrition Assistance Program (SNAP) serves as the foundation of America's national nutrition safety net. It is the nation's first line of defense against food insecurity and offers a powerful tool to improve nutrition among low-income individuals. SNAP is the largest of the 15 domestic food and nutrition assistance programs…

  19. Synaptosome-Associated Protein 25 (SNAP25) Gene Association Analysis Revealed Risk Variants for ASD, in Iranian Population.

    PubMed

    Safari, Mohammad Reza; Omrani, Mir Davood; Noroozi, Rezvan; Sayad, Arezou; Sarrafzadeh, Shaghayegh; Komaki, Alireza; Manjili, Fateme Asadzadeh; Mazdeh, Mehrdokht; Ghaleiha, Ali; Taheri, Mohammad

    2017-03-01

    Autism spectrum disorder (ASD) is a common, complex neurological condition, affecting approximately 1% of people worldwide. Monogenic neurodevelopmental disorders which showed autistic behavior patterns have suggested synaptic dysfunction, as a key mechanism in the pathophysiology of ASD. Subsequently, genes involved in synaptic signaling have been investigated with a priority for candidate gene studies. A synaptosomal-associated protein 25 (SNAP25) gene plays a crucial role in the central nervous system, contributing to exocytosis by targeting and fusion of vesicles to the cell membrane. Studies have shown a correlation between aberrant expression of the SNAP25 and a variety of brain diseases. Single nucleotide polymorphisms (SNPs) in this gene are associated with several psychiatric diseases, such as bipolar, schizophrenia, and attention-deficit/hyperactivity disorder. The aim of the present study was to investigate whether polymorphisms (rs3746544 and rs1051312) in the regulatory 3'-untranslated region (3'UTR) of the SNAP25 gene have an association with ASD in unrelated Iranian case (N = 524)-control (N = 472) samples. We observed robust association of the rs3746544 SNP and ASD patients, in both allele and haplotype-based analyses. Our results supported the previous observations and indicated a possible role for SNAP25 polymorphisms as susceptibility genetic factors involved in developing ASD.

  20. A role for SNAP-25 but not VAMPs in store-mediated Ca2+ entry in human platelets

    PubMed Central

    Redondo, Pedro C; Harper, Alan G S; Salido, Ginés M; Pariente, Jose A; Sage, Stewart O; Rosado, Juan A

    2004-01-01

    Store-mediated Ca2+ entry (SMCE) is a major mechanism for Ca2+ influx in non-excitable cells. Recently, a conformational coupling mechanism allowing coupling between transient receptor potential channels (TRPCs) and IP3 receptors has been proposed to activate SMCE. Here we have investigated the role of two soluble N-ethylmaleimide-sensitive-factor attachment protein receptors (SNAREs), which are involved in membrane trafficking and docking, in SMCE in human platelets. We found that the synaptosome-associated protein (SNAP-25) and the vesicle-associated membrane proteins (VAMP) coimmunoprecipitate with hTRPC1 in platelets. Treatment with botulinum toxin (BoNT) E or with tetanus toxin (TeTx), induced cleavage and inactivation of SNAP-25 and VAMPs, respectively. BoNTs significantly reduced thapsigargin- (TG) and agonist-evoked SMCE. Treatment with BoNTs once SMCE had been activated decreased Ca2+ entry, indicating that SNAP-25 is required for the activation and maintenance of SMCE. In contrast, treatment with TeTx had no effect on either the activation or the maintenance of SMCE in platelets. Finally, treatment with BoNT E impaired the coupling between naturally expressed hTRPC1 and IP3 receptor type II in platelets. From these findings we suggest SNAP-25 has a role in SMCE in human platelets. PMID:15121806

  1. Rapid Contour-based Segmentation for 18F-FDG PET Imaging of Lung Tumors by Using ITK-SNAP: Comparison to Expert-based Segmentation.

    PubMed

    Besson, Florent L; Henry, Théophraste; Meyer, Céline; Chevance, Virgile; Roblot, Victoire; Blanchet, Elise; Arnould, Victor; Grimon, Gilles; Chekroun, Malika; Mabille, Laurence; Parent, Florence; Seferian, Andrei; Bulifon, Sophie; Montani, David; Humbert, Marc; Chaumet-Riffaud, Philippe; Lebon, Vincent; Durand, Emmanuel

    2018-04-03

    Purpose To assess the performance of the ITK-SNAP software for fluorodeoxyglucose (FDG) positron emission tomography (PET) segmentation of complex-shaped lung tumors compared with an optimized, expert-based manual reference standard. Materials and Methods Seventy-six FDG PET images of thoracic lesions were retrospectively segmented by using ITK-SNAP software. Each tumor was manually segmented by six raters to generate an optimized reference standard by using the simultaneous truth and performance level estimate algorithm. Four raters segmented 76 FDG PET images of lung tumors twice by using ITK-SNAP active contour algorithm. Accuracy of ITK-SNAP procedure was assessed by using Dice coefficient and Hausdorff metric. Interrater and intrarater reliability were estimated by using intraclass correlation coefficients of output volumes. Finally, the ITK-SNAP procedure was compared with currently recommended PET tumor delineation methods on the basis of thresholding at 41% volume of interest (VOI; VOI 41 ) and 50% VOI (VOI 50 ) of the tumor's maximal metabolism intensity. Results Accuracy estimates for the ITK-SNAP procedure indicated a Dice coefficient of 0.83 (95% confidence interval: 0.77, 0.89) and a Hausdorff distance of 12.6 mm (95% confidence interval: 9.82, 15.32). Interrater reliability was an intraclass correlation coefficient of 0.94 (95% confidence interval: 0.91, 0.96). The intrarater reliabilities were intraclass correlation coefficients above 0.97. Finally, VOI 41 and VOI 50 accuracy metrics were as follows: Dice coefficient, 0.48 (95% confidence interval: 0.44, 0.51) and 0.34 (95% confidence interval: 0.30, 0.38), respectively, and Hausdorff distance, 25.6 mm (95% confidence interval: 21.7, 31.4) and 31.3 mm (95% confidence interval: 26.8, 38.4), respectively. Conclusion ITK-SNAP is accurate and reliable for active-contour-based segmentation of heterogeneous thoracic PET tumors. ITK-SNAP surpassed the recommended PET methods compared with ground truth

  2. The SNaP system: biomechanical and animal model testing of a novel ultraportable negative-pressure wound therapy system.

    PubMed

    Fong, Kenton D; Hu, Dean; Eichstadt, Shaundra; Gupta, Deepak M; Pinto, Moshe; Gurtner, Geoffrey C; Longaker, Michael T; Lorenz, H Peter

    2010-05-01

    Negative-pressure wound therapy is traditionally achieved by attaching an electrically powered pump to a sealed wound bed and applying subatmospheric pressure by means of gauze or foam. The Smart Negative Pressure (SNaP) System (Spiracur, Inc., Sunnyvale, Calif.) is a novel ultraportable negative-pressure wound therapy system that does not require an electrically powered pump. Negative pressure produced by the SNaP System, and a powered pump, the wound vacuum-assisted closure advanced-therapy system (Kinetic Concepts, Inc., San Antonio, Texas), were compared in vitro using bench-top pressure sensor testing and microstrain and stress testing with pressure-sensitive film and micro-computed tomographic scan analysis. In addition, to test in vivo efficacy, 10 rats underwent miniaturized SNaP (mSNaP) device placement on open wounds. Subject rats were randomized to a system activation group (approximately -125 mmHg) or a control group (atmospheric pressure). Wound measurements and histologic data were collected for analysis. Bench measurement revealed nearly identical negative-pressure delivery and mechanical strain deformation patterns between both systems. Wounds treated with the mSNaP System healed faster, with decreased wound size by postoperative day 7 (51 percent versus 12 percent reduction; p < 0.05) and had more rapid complete reepithelialization (21 days versus 32 days; p < 0.05). The mSNaP device also induced robust granulation tissue formation. The SNaP System and an existing electrically powered negative-pressure wound therapy system have similar biomechanical properties and functional wound-healing benefits. The potential clinical efficacy of the SNaP device for the treatment of wounds is supported.

  3. The Interstellar Mapping and Acceleration Probe - A Mission to Discover the Origin of Particle Acceleration and its Fundamental Connection to the Global Interstellar Interaction

    NASA Astrophysics Data System (ADS)

    Schwadron, N.

    2017-12-01

    Our piece of cosmic real-estate, the heliosphere, is the domain of all human existence - an astrophysical case-history of the successful evolution of life in a habitable system. The Interstellar Boundary Explorer (IBEX) was the first mission to explore the global heliosphere and in concert with Voyager 1 and Voyager 2 is discovering a fundamentally new and uncharted physical domain of the outer heliosphere. In parallel, Cassini/INCA maps the global heliosphere at energies ( 5-55 keV) above those measured by IBEX. The enigmatic IBEX ribbon and the INCA belt were unanticipated discoveries demonstrating that much of what we know or think we understand about the outer heliosphere needs to be revised. The global structure of the heliosphere is highly complex and influenced by competing factors ranging from the local interstellar magnetic field, suprathermal populations both within and beyond the heliopause, and the detailed flow properties of the LISM. Global heliospheric structure and microphysics in turn influences the acceleration of energetic particles and creates feedbacks that modify the interstellar interaction as a whole. The next quantum leap enabled by IMAP will open new windows on the frontier of Heliophysics and probe the acceleration of suprathermal and higher energy particles at a time when the space environment is rapidly evolving. IMAP ultimately connects the acceleration processes observed directly at 1 AU with unprecedented sensitivity and temporal resolution with the global structure of our heliosphere. The remarkable synergy between IMAP, Voyager 1 and Voyager 2 will remain for at least the next decade as Voyager 1 pushes further into the interstellar domain and Voyager 2 moves through the heliosheath. IMAP, like ACE before it, will be a keystone of the Heliophysics System Observatory by providing comprehensive energetic particle, pickup ion, suprathermal ion, neutral atom, solar wind, solar wind heavy ion, and magnetic field observations to diagnose

  4. Towards Lego Snapping; Integration of Carbon Nanotubes and Few-Layer Graphene

    NASA Astrophysics Data System (ADS)

    Nasseri, Mohsen; Boland, Mathias; Farrokhi, M. Javad; Strachan, Douglas

    Integration of semiconducting, conducting, and insulating nanomaterials into precisely aligned complicated systems is one of the main challenges to the ultimate size scaling of electronic devices, which is a key goal in nanoscience and nanotechnology. This integration could be made more effective through controlled alignment of the crystallographic lattices of the nanoscale components. Of the vast number of materials of atomically-thin materials, two of the sp2 bonded carbon structures, graphene and carbon nanotubes, are ideal candidates for this type of application since they are built from the same backbone carbon lattice. Here we report carbon nanotube and graphene hybrid nanostructures fabricated through their catalytic synthesis and etching. The growth formations we have investigated through various high-resolution microscopy techniques provide evidence of lego-snapped interfaces between nanotubes and graphene into device-relevant orientations. We will finish with a discussion of the various size and energy regimes relevant to these lego-snapped interfaces and their implications on developing these integrated formations.

  5. Low-energy (< 200 eV) electron acceleration by ULF waves in the plasmaspheric boundary layer: Van Allen Probes observation

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

    Ren, Jie; Zong, Q. G.; Miyoshi, Y.

    Here, we report observational evidence of cold plamsmaspheric electron (< 200 eV) acceleration by ultra-low-frequency (ULF) waves in the plasmaspheric boundary layer on 10 September 2015. Strongly enhanced cold electron fluxes in the energy spectrogram were observed along with second harmonic mode waves with a period of about 1 minute which lasted several hours during two consecutive Van Allen Probe B orbits. Cold electron (<200 eV) and energetic proton (10-20 keV) bi-directional pitch angle signatures observed during the event are suggestive of the drift-bounce resonance mechanism. The correlation between enhanced energy fluxes and ULF waves leads to the conclusions thatmore » plasmaspheric dynamics is strongly affected by ULF waves. Van Allen Probe A and B, GOES 13, GOES 15 and MMS 1 observations suggest ULF waves in the event were strongest on the dusk-side magnetosphere. Measurements from MMS 1 contain no evidence of an external wave source during the period when ULF waves and injected energetic protons with a bump-on-tail distribution were detected by Van Allen Probe B. This suggests that the observed ULF waves were probably excited by a localized drift-bounce resonant instability, with the free energy supplied by substorm-injected energetic protons. The observations by Van Allen Probe B suggest that energy transfer between particle species in different energy ranges can take place through the action of ULF waves, demonstrating the important role of these waves in the dynamical processes of the inner magnetosphere.« less

  6. Low-energy (< 200 eV) electron acceleration by ULF waves in the plasmaspheric boundary layer: Van Allen Probes observation

    DOE PAGES

    Ren, Jie; Zong, Q. G.; Miyoshi, Y.; ...

    2017-08-30

    Here, we report observational evidence of cold plamsmaspheric electron (< 200 eV) acceleration by ultra-low-frequency (ULF) waves in the plasmaspheric boundary layer on 10 September 2015. Strongly enhanced cold electron fluxes in the energy spectrogram were observed along with second harmonic mode waves with a period of about 1 minute which lasted several hours during two consecutive Van Allen Probe B orbits. Cold electron (<200 eV) and energetic proton (10-20 keV) bi-directional pitch angle signatures observed during the event are suggestive of the drift-bounce resonance mechanism. The correlation between enhanced energy fluxes and ULF waves leads to the conclusions thatmore » plasmaspheric dynamics is strongly affected by ULF waves. Van Allen Probe A and B, GOES 13, GOES 15 and MMS 1 observations suggest ULF waves in the event were strongest on the dusk-side magnetosphere. Measurements from MMS 1 contain no evidence of an external wave source during the period when ULF waves and injected energetic protons with a bump-on-tail distribution were detected by Van Allen Probe B. This suggests that the observed ULF waves were probably excited by a localized drift-bounce resonant instability, with the free energy supplied by substorm-injected energetic protons. The observations by Van Allen Probe B suggest that energy transfer between particle species in different energy ranges can take place through the action of ULF waves, demonstrating the important role of these waves in the dynamical processes of the inner magnetosphere.« less

  7. The unhealthy food environment does not modify the association between obesity and participation in the Supplemental Nutrition Assistance Program (SNAP) in Los Angeles County.

    PubMed

    Chaparro, M Pia; Harrison, Gail G; Wang, May C; Seto, Edmund Y W; Pebley, Anne R

    2017-01-14

    Participation in the Supplemental Nutrition Assistance Program (SNAP) has been linked to an increased risk of obesity, but not much is known about the mechanisms behind this association. The objective of this study was to determine if the neighborhood density of unhealthy food outlets modifies the association between obesity and participation in SNAP. Data comes from the first wave of the Los Angeles Family and Neighborhood Survey; included are a subsample of adults (18+ years) who were SNAP participants or eligible non-participants (N = 1,176). We carried out multilevel analyses with obesity (BMI ≥ 30 Kg/m 2 ), SNAP participation, and the neighborhood density of unhealthy food outlets as dependent, independent and modifying variables, respectively, controlling for age, gender, race/ethnicity, marital status, working status, mental health, and neighborhood poverty. SNAP participants had double the odds of obesity compared to eligible non-participants (OR = 2.02; 95%CI = 1.44-2.83). However, the neighborhood density of unhealthy food outlets did not modify this association. SNAP participation was associated with higher odds of obesity in our primarily Hispanic sample in Los Angeles County, with no effect modification found for the unhealthy portion of the food environment. More research is needed with additional food environment measures to confirm our null findings. Additional research is needed to elucidate the mechanisms linking SNAP participation and obesity as they remain unclear.

  8. A Pilot Study of the Snap & Sniff Threshold Test.

    PubMed

    Jiang, Rong-San; Liang, Kai-Li

    2018-05-01

    The Snap & Sniff ® Threshold Test (S&S) has been recently developed to determine the olfactory threshold. The aim of this study was to further evaluate the validity and test-retest reliability of the S&S. The olfactory thresholds of 120 participants were determined using both the Smell Threshold Test (STT) and the S&S. The participants included 30 normosmic volunteers and 90 patients (60 hyposmic, 30 anosmic). The normosmic participants were retested using the STT and S&S at an intertest interval of at least 1 day. The mean olfactory threshold determined with the S&S was -6.76 for the normosmic participants, -3.79 for the hyposmic patients, and -2 for the anosmic patients. The olfactory thresholds were significantly different across the 3 groups ( P < .001). Snap & Sniff-based and STT-based olfactory thresholds were correlated weakly in the normosmic group (correlation coefficient = 0.162, P = .391) but more strongly correlated in the patient groups (hyposmic: correlation coefficient = 0.376, P = .003; anosmic: correlation coefficient = 1.0). The test-retest correlation for the S&S-based olfactory thresholds was 0.384 ( P = .036). Based on validity and test-retest reliability, we concluded that the S&S is a proper test for olfactory thresholds.

  9. Reduction in Thrombosis and Bacterial Adhesion with 7 Day Implantation of S-Nitroso-N-acetylpenicillamine (SNAP)-Doped Elast-eon E2As Catheters in Sheep

    PubMed Central

    Brisbois, Elizabeth J.; Davis, Ryan P.; Jones, Anna M.; Major, Terry C.; Bartlett, Robert H.; Meyerhoff, Mark E.; Handa, Hitesh

    2015-01-01

    Thrombosis and infection are two common problems associated with blood-contacting medical devices such as catheters. Nitric oxide (NO) is known to be a potent antimicrobial agent as well as an inhibitor of platelet activation and adhesion. Healthy endothelial cells that line the inner walls of all blood vessels exhibit a NO flux of 0.5~4×10−10 mol cm−2 min−1 that helps prevent thrombosis. Materials with a NO flux that is equivalent to this level are expected to exhibit similar anti-thrombotic properties. In this study, NO-releasing catheters were fabricated by incorporating S-nitroso-N-acetylpenicillamine (SNAP) in the Elast-eon E2As polymer. The SNAP/E2As catheters release physiological levels of NO for up to 20 d, as measured by chemiluminescence. Furthermore, SNAP is stable in the E2As polymer, retaining 89% of the initial SNAP after ethylene oxide (EO) sterilization. The SNAP/E2As and E2As control catheters were implanted in sheep veins for 7 d to examine the effect on thrombosis and bacterial adhesion. The SNAP/E2As catheters reduced the thrombus area when compared to the control (1.56 ± 0.76 and 5.06 ± 1.44 cm2, respectively). A 90% reduction in bacterial adhesion was also observed for the SNAP/E2As catheters as compared to the controls. The results suggest that the SNAP/E2As polymer has the potential to improve the hemocompatibility and bactericidal activity of intravascular catheters, as well as other blood-contacting medical devices (e.g., vascular grafts, extracorporeal circuits). PMID:25685358

  10. SU-F-J-25: Position Monitoring for Intracranial SRS Using BrainLAB ExacTrac Snap Verification

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

    Jang, S; McCaw, T; Huq, M

    2016-06-15

    Purpose: To determine the accuracy of position monitoring with BrainLAB ExacTrac snap verification following couch rotations during intracranial SRS. Methods: A CT scan of an anthropomorphic head phantom was acquired using 1.25mm slices. The isocenter was positioned near the centroid of the frontal lobe. The head phantom was initially aligned on the treatment couch using cone-beam CT, then repositioned using ExacTrac x-ray verification with residual errors less than 0.2mm and 0.2°. Snap verification was performed over the full range of couch angles in 15° increments with known positioning offsets of 0–3mm applied to the phantom along each axis. At eachmore » couch angle, the smallest tolerance was determined for which no positioning deviation was detected. Results: For couch angles 30°–60° from the center position, where the longitudinal axis of the phantom is approximately aligned with the beam axis of one x-ray tube, snap verification consistently detected positioning errors exceeding the maximum 8mm tolerance. Defining localization error as the difference between the known offset and the minimum tolerance for which no deviation was detected, the RMS error is mostly less than 1mm outside of couch angles 30°–60° from the central couch position. Given separate measurements of patient position from the two imagers, whether to proceed with treatment can be determined by the criterion of a reading within tolerance from just one (OR criterion) or both (AND criterion) imagers. Using a positioning tolerance of 1.5mm, snap verification has sensitivity and specificity of 94% and 75%, respectively, with the AND criterion, and 67% and 93%, respectively, with the OR criterion. If readings exceeding maximum tolerance are excluded, the sensitivity and specificity are 88% and 86%, respectively, with the AND criterion. Conclusion: With a positioning tolerance of 1.5mm, ExacTrac snap verification can be used during intracranial SRS with sensitivity and specificity

  11. Non-target captures during small mammal trapping with snap traps

    Treesearch

    David G. Peitz; Philip A. Tappe; Ronald E. Thill; Roger W. Perry; M. Anthony Melchiors; T. Bently Wigley

    2001-01-01

    There is little published information available on non-target captures during small mammal trapping. We used a variety of snap traps baited with a rolled oat-peanut butter mix to capture 2,054 individuals from 9 genera of small mammals in a study of small mammal and avian community structure in riparian areas and adjacent loblolly pine (Pinus taeda) plantations. We...

  12. REPORT OF THE QUALIFICATION TESTING OF SNAP 10A FUSISTORS

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

    Holtwick, J.S. III; Nowell, V.P.

    1963-07-31

    Qualification testing of SNAP 10A fusistors was performed. Test operations included: visual inspection, insulation resistance, dielectric strength, and d-c resistance testing prior to subjecting the fusisters to environmental testing; opening-time testing prior to, during, and following vacuum and temperature testing; and insulation resistance, dielectric strength, and d-c resistance testing following environmental applications of temperature, vacuum, and sinusoidal vibration. (auth)

  13. A Comparison of Snap Traps for Evaluating Small Mammal Populations

    Treesearch

    Roger W. Perry; Philip A. Tappe; David G. Peitz; Ronald E. Thill; M. Anthony Melchoirs; T. Bently Wigley

    1996-01-01

    The authors compared rat, mouse, and museum special snap traps to determine if differences existed in capture efficiency of small mammals and whether type of trap affected indices of richness, evenness, and diversity. Small mammals were trapped in 57 streamside study areas in 1990 to 1995 in the Ouachita Mountains, AR. Efficiency of mouse traps was equal to or greater...

  14. Nonlinear modes of snap-through motions of a shallow arch

    NASA Astrophysics Data System (ADS)

    Breslavsky, I.; Avramov, K. V.; Mikhlin, Yu.; Kochurov, R.

    2008-03-01

    Nonlinear modes of snap-through motions of a shallow arch are analyzed. Dynamics of shallow arch is modeled by a two-degree-of-freedom system. Two nonlinear modes of this discrete system are treated. The methods of Ince algebraization and Hill determinants are used to study stability of nonlinear modes. The analytical results are compared with the data of the numerical simulations.

  15. On the presence of plutonium in Madagascar following the SNAP-9A satellite failure.

    PubMed

    Rääf, C; Holm, E; Rabesiranana, N; Garcia-Tenorio, R; Chamizo, E

    2017-10-01

    This study examined the 238 Pu and 239+240 Pu activity concentration and the 240 Pu/ 239 Pu atomic ratio in peat bogs sampled in 2012 from marshlands in central Madagascar. The purpose was to investigate the presence of plutonium isotopes, 238, 239, 240 Pu, from the 1964 satellite failure carrying a SNAP-9A radiothermal generator. With an average 238 Pu/ 239+240 Pu activity ratio of 0.165 ± 0.02 (decay corrected to 1964), the peat bogs in Madagascar exhibit similar values as the ones found in the southeastern African continent, except they are one order of magnitude higher than expected (0.025) from global fallout in the Southern Hemisphere. The 240 Pu/ 239 Pu atomic ratio showed a distinct decrease for layers dating back to the mid-1960s (down to 0.069 compared with an anticipated ratio of 0.17 for global fallout), indicating that the SNAP-9A failure also resulted in an elevated deposition of 239 Pu. The obtained results demonstrate that further Pu analysis in Madagascar and in southeastern continental Africa is necessary to fully account for the regional Pu deposition from the SNAP-9A event. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Evaluation of diamide insecticides co-applied with other agrochemicals at various times to manage Ostrinia nubilalis in processing snap bean.

    PubMed

    Huseth, Anders S; Groves, Russell L; Chapman, Scott A; Nault, Brian A

    2015-12-01

    Multiple applications of pyrethroid insecticides are used to manage European corn borer, Ostrinia nubilalis Hübner, in snap bean, but new diamide insecticides may reduce application frequency. In a 2 year small-plot study, O. nubilalis control was evaluated by applying cyantraniliprole (diamide) and bifenthrin (pyrethroid) insecticides at one of three phenological stages (bud, bloom and pod formation) of snap bean development. Co-application of these insecticides with either herbicides or fungicides was also examined as a way to reduce the total number of sprays during a season. Cyantraniliprole applications timed either during bloom or during pod formation controlled O. nubilalis better than similar timings of bifenthrin. Co-applications of insecticides with fungicides controlled O. nubilalis as well as insecticide applications alone. Insecticides applied either alone or with herbicides during bud stage did not control this pest. Diamides are an alternative to pyrethroids for the management of O. nubilalis in snap bean. Adoption of diamides by snap bean growers could improve the efficiency of production by reducing the number of sprays required each season. © 2015 Society of Chemical Industry.

  17. Cosmological consistency tests of gravity theory and cosmic acceleration

    NASA Astrophysics Data System (ADS)

    Ishak-Boushaki, Mustapha B.

    2017-01-01

    Testing general relativity at cosmological scales and probing the cause of cosmic acceleration are among the important objectives targeted by incoming and future astronomical surveys and experiments. I present our recent results on consistency tests that can provide insights about the underlying gravity theory and cosmic acceleration using cosmological data sets. We use statistical measures, the rate of cosmic expansion, the growth rate of large scale structure, and the physical consistency of these probes with one another.

  18. The role of SNAP in home food availability and dietary intake among WIC participants facing unstable housing

    PubMed Central

    Bruening, Meg; McClain, Darya; Moramarco, Michael; Reifsnider, Elizabeth

    2016-01-01

    Objective Little nutrition research has been conducted among families with unstable housing. The objective of this study was to examine the role of food stamps (i.e. Supplemental Nutrition Assistance Program; SNAP) in home food availability and dietary intake among WIC families who experienced unstable housing. Design Cross-sectional study among vulnerable families. Sample Low-income, multi-ethnic families with children participating in WIC (n=54). Measurements Dietary intake was assessed with 24-hour recalls. Home food availability was assessed with an adapted home food inventory for low-income, multi-ethnic families. Validation results from adapted home food inventory for these families are also reported. Results SNAP households had more foods than non-SNAP households; few significant associations were observed between food availability and child dietary intake. Conclusions With few exceptions, the home food environment was not related to children’s dietary intake among these vulnerable families. More research is needed on food access for families facing unstable housing. PMID:28084013

  19. Optical probing of high intensity laser interaction with micron-sized cryogenic hydrogen jets

    NASA Astrophysics Data System (ADS)

    Ziegler, Tim; Rehwald, Martin; Obst, Lieselotte; Bernert, Constantin; Brack, Florian-Emanuel; Curry, Chandra B.; Gauthier, Maxence; Glenzer, Siegfried H.; Göde, Sebastian; Kazak, Lev; Kraft, Stephan D.; Kuntzsch, Michael; Loeser, Markus; Metzkes-Ng, Josefine; Rödel, Christian; Schlenvoigt, Hans-Peter; Schramm, Ulrich; Siebold, Mathias; Tiggesbäumker, Josef; Wolter, Steffen; Zeil, Karl

    2018-07-01

    Probing the rapid dynamics of plasma evolution in laser-driven plasma interactions provides deeper understanding of experiments in the context of laser-driven ion acceleration and facilitates the interplay with complementing numerical investigations. Besides the microscopic scales involved, strong plasma (self-)emission, predominantly around the harmonics of the driver laser, often complicates the data analysis. We present the concept and the implementation of a stand-alone probe laser system that is temporally synchronized to the driver laser, providing probing wavelengths beyond the harmonics of the driver laser. The capability of this system is shown during a full-scale laser proton acceleration experiment using renewable cryogenic hydrogen jet targets. For further improvements, we studied the influence of probe color, observation angle of the probe and temporal contrast of the driver laser on the probe image quality.

  20. Electric field measurement in microwave discharge ion thruster with electro-optic probe.

    PubMed

    Ise, Toshiyuki; Tsukizaki, Ryudo; Togo, Hiroyoshi; Koizumi, Hiroyuki; Kuninaka, Hitoshi

    2012-12-01

    In order to understand the internal phenomena in a microwave discharge ion thruster, it is important to measure the distribution of the microwave electric field inside the discharge chamber, which is directly related to the plasma production. In this study, we proposed a novel method of measuring a microwave electric field with an electro-optic (EO) probe based on the Pockels effect. The probe, including a cooling system, contains no metal and can be accessed in the discharge chamber with less disruption to the microwave distribution. This method enables measurement of the electric field profile under ion beam acceleration. We first verified the measurement with the EO probe by a comparison with a finite-difference time domain numerical simulation of the microwave electric field in atmosphere. Second, we showed that the deviations of the reflected microwave power and the beam current were less than 8% due to inserting the EO probe into the ion thruster under ion beam acceleration. Finally, we successfully demonstrated the measurement of the electric-field profile in the ion thruster under ion beam acceleration. These measurements show that the electric field distribution in the thruster dramatically changes in the ion thruster under ion beam acceleration as the propellant mass flow rate increases. These results indicate that this new method using an EO probe can provide a useful guide for improving the propulsion of microwave discharge ion thrusters.

  1. SNAP Participation in Preschool-Aged Children and Prevalence of Overweight and Obesity

    ERIC Educational Resources Information Center

    Simmons, Shannon; Alexander, Jeffrey L.; Ewing, Helen; Whetzel, Stephanie

    2012-01-01

    Background: An increased prevalence of overweight and obesity for adults on government-funded nutrition assistance, such as the Supplemental Nutrition Assistance Program (SNAP), has been observed; however, this association among preschool-aged children is not well understood. Longitudinal research designs tracking changes in body mass…

  2. The Australian National Sub-acute and Non-acute Patient Casemix Classification (AN-SNAP): its application and value in a stroke rehabilitation programme.

    PubMed

    Lowthian, P; Disler, P; Ma, S; Eagar, K; Green, J; de Graaff, S

    2000-10-01

    To investigate whether the Australian National Sub-acute and Non-acute Patient Casemix Classification (SNAP) and Functional Independence Measure and Functional Related Group (Version 2) (FIM-FRG2) casemix systems can be used to predict functional outcome, and reduce the variance of length of stay (LOS) of patients undergoing rehabilitation after strokes. The study comprised a retrospective analysis of the records of patients admitted to the Cedar Court Healthsouth Rehabilitation Hospital for rehabilitation after stroke. The sample included 547 patients (83.3% of those admitted with stroke during this period). Patient data were stratified for analysis into the five SNAP or nine FIM-FRG2 groups, on the basis of the admission FIM scores and age. The AN-SNAP classification accounted for a 30.7% reduction of the variance of LOS, and 44.2% of motor FIM, and the FIM-FRG2 accounts for 33.5% and 56.4% reduction respectively. Comparison of the Cedar Court with the national AN-SNAP data showed differences in the LOS and functional outcomes of older, severely disabled patients. Intensive rehabilitation in selected patients of this type appears to have positive effects, albeit with a slightly longer period of inpatient rehabilitation. Casemix classifications can be powerful management tools. Although FIM-FRG2 accounts for more reduction in variance than SNAP, division into nine groups meant that some contained few subjects. This paper supports the introduction of AN-SNAP as the standard casemix tool for rehabilitation in Australia, which will hopefully lead to rational, adequate funding of the rehabilitation phase of care.

  3. Van Allen Probes observations of structured whistler mode activity and coincident electron Landau acceleration inside a remnant plasmaspheric plume

    NASA Astrophysics Data System (ADS)

    Woodroffe, J. R.; Jordanova, V. K.; Funsten, H. O.; Streltsov, A. V.; Bengtson, M. T.; Kletzing, C. A.; Wygant, J. R.; Thaller, S. A.; Breneman, A. W.

    2017-03-01

    We present observations from the Van Allen Probes spacecraft that identify a region of intense whistler mode activity within a large density enhancement outside of the plasmasphere. We speculate that this density enhancement is part of a remnant plasmaspheric plume, with the observed wave being driven by a weakly anisotropic electron injection that drifted into the plume and became nonlinearly unstable to whistler emission. Particle measurements indicate that a significant fraction of thermal (<100 eV) electrons within the plume were subject to Landau acceleration by these waves, an effect that is naturally explained by whistler emission within a gradient and high-density ducting inside a density enhancement.

  4. The Schedule for Nonadaptive and Adaptive Personality for Youth (SNAP-Y): A New Measure for Assessing Adolescent Personality and Personality Pathology

    ERIC Educational Resources Information Center

    Linde, Jennifer A.; Stringer, Deborah; Simms, Leonard J.; Clark, Lee Anna

    2013-01-01

    The Schedule for Nonadaptive and Adaptive Personality-Youth Version (SNAP-Y) is a new, reliable self-report questionnaire that assesses 15 personality traits relevant to both normal-range personality and the alternative "DSM"-5 model for personality disorder. Community adolescents, 12 to 18 years old (N = 364), completed the SNAP-Y; 347…

  5. Food and drink consumption among 1-5-year-old Los Angeles County children from households receiving dual SNAP and WIC v. only WIC benefits.

    PubMed

    Liu, Jane; Kuo, Tony; Jiang, Lu; Robles, Brenda; Whaley, Shannon E

    2017-10-01

    The Supplemental Nutrition Assistance Program (SNAP) and the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) are two of the more well-known food assistance programmes in the USA. The current study describes food consumption patterns of children aged 1-5 years living in households dually enrolled in these two programmes v. households enrolled only in WIC. Food consumption and SNAP participation were assessed using data from the 2014 Survey of Los Angeles County (LAC) WIC Participants and the Follow-Up Survey of the same households that were also SNAP beneficiaries. Telephone interviews were conducted with WIC parents regarding each child's (i.e. beneficiary's) food consumption patterns. Follow-up interviews were conducted with those who reported receiving SNAP. Multivariable regression analyses were performed to assess the relationships between food and beverage consumption and dual v. single food assistance programme participation. LAC, California. Children of WIC-enrolled households in LAC during 2014 (n 3248). This included a sub-sample of dual WIC- and SNAP-enrolled households (n 1295). Survey participants were the beneficiaries' parents. Children from dually enrolled households consumed 1·03 (P<0·05) and 1·04 (P<0·01) more servings of fruits and vegetables daily respectively, 1·07 more sugar-sweetened beverages daily (P<0·001) and ate sweets/sweetened foods 1·04 more times daily (P<0·001) than children from households participating only in WIC. Results suggest that SNAP+WIC enrolment is associated with increased consumption of both healthy foods and foods containing minimal nutritional value. Complementary nutrition education efforts across the two programmes may help beneficiaries maximize healthful food purchases with SNAP dollars.

  6. THE EFFECTS OF OXIDANT AIR POLLUTANTS ON SOYBEANS, SNAP BEANS AND POTATOES

    EPA Science Inventory

    During the past 5 years the impact of photochemical oxidants on soybeans and snap beans in Maryland and on potatoes in Virginia and Delaware was assessed with open-top chambers. The mean yields of four selected soybean varieties grown in open-top chambers with carbon-filtered air...

  7. The mobility of food retailers: How proximity to SNAP authorized food retailers changed in Atlanta during the Great Recession.

    PubMed

    Shannon, Jerry; Bagwell-Adams, Grace; Shannon, Sarah; Lee, Jung Sun; Wei, Yangjiaxin

    2018-07-01

    Retailer mobility, defined as the shifting geographic patterns of retail locations over time, is a significant but understudied factor shaping neighborhood food environments. Our research addresses this gap by analyzing changes in proximity to SNAP authorized chain retailers in the Atlanta urban area using yearly data from 2008 to 2013. We identify six demographically similar geographic clusters of census tracts in our study area based on race and economic variables. We use these clusters in exploratory data analysis to identify how proximity to the twenty largest retail food chains changed during this period. We then use fixed effects models to assess how changing store proximity is associated with race, income, participation in SNAP, and population density. Our results show clear differences in geographic distribution between store categories, but also notable variation within each category. Increasing SNAP enrollment predicted decreased distances to almost all small retailers but increased distances to many large retailers. Our chain-focused analysis underscores the responsiveness of small retailers to changes in neighborhood SNAP participation and the value of tracking chain expansion and contraction in markets across time. Better understanding of retailer mobility and the forces that drive it can be a productive avenue for future research. Copyright © 2018 Elsevier Ltd. All rights reserved.

  8. Geometrically controlled snapping transitions in shells with curved creases.

    PubMed

    Bende, Nakul Prabhakar; Evans, Arthur A; Innes-Gold, Sarah; Marin, Luis A; Cohen, Itai; Hayward, Ryan C; Santangelo, Christian D

    2015-09-08

    Curvature and mechanics are intimately connected for thin materials, and this coupling between geometry and physical properties is readily seen in folded structures from intestinal villi and pollen grains to wrinkled membranes and programmable metamaterials. While the well-known rules and mechanisms behind folding a flat surface have been used to create deployable structures and shape transformable materials, folding of curved shells is still not fundamentally understood. Shells naturally deform by simultaneously bending and stretching, and while this coupling gives them great stability for engineering applications, it makes folding a surface of arbitrary curvature a nontrivial task. Here we discuss the geometry of folding a creased shell, and demonstrate theoretically the conditions under which it may fold smoothly. When these conditions are violated we show, using experiments and simulations, that shells undergo rapid snapping motion to fold from one stable configuration to another. Although material asymmetry is a proven mechanism for creating this bifurcation of stability, for the case of a creased shell, the inherent geometry itself serves as a barrier to folding. We discuss here how two fundamental geometric concepts, creases and curvature, combine to allow rapid transitions from one stable state to another. Independent of material system and length scale, the design rule that we introduce here explains how to generate snapping transitions in arbitrary surfaces, thus facilitating the creation of programmable multistable materials with fast actuation capabilities.

  9. S-Nitroso-N-acetylpenicillamine (SNAP) Impregnated Silicone Foley Catheters: A Potential Biomaterial/Device To Prevent Catheter-Associated Urinary Tract Infections

    PubMed Central

    2016-01-01

    Urinary Foley catheters are utilized for management of hospitalized patients and are associated with high rates of urinary tract infections (UTIs). Nitric oxide (NO) potently inhibits microbial biofilm formation, which is the primary cause of catheter associated UTIs (CAUTIs). Herein, commercial silicone Foley catheters are impregnated via a solvent swelling method with S-nitroso-N-acetyl-D-penicillamine (SNAP), a synthetic NO donor that exhibits long-term NO release and stability when incorporated into low water-uptake polymers. The proposed catheters generate NO surface-fluxes >0.7 × 10–10 mol min–1 cm–2 for over one month under physiological conditions, with minimal SNAP leaching. These biomedical devices are demonstrated to significantly decrease formation of biofilm on the surface of the catheter tubings over 3, 7, and 14 day periods by microbial species (Staphylococcus epidermidis and Proteus mirabilis) commonly causing CAUTIs. Toxicity assessment demonstrates that the SNAP-impregnated catheters are fully biocompatible, as extracts of the catheter tubings score 0 on a 3-point grading scale using an accepted mouse fibroblast cell-line toxicity model. Consequently, SNAP-impregnated silicone Foley catheters can likely provide an efficient strategy to greatly reduce the occurrence of nosocomial CAUTIs. PMID:26462294

  10. Parent and Teacher SNAP-IV Ratings of Attention Deficit Hyperactivity Disorder Symptoms: Psychometric Properties and Normative Ratings from a School District Sample

    ERIC Educational Resources Information Center

    Bussing, Regina; Fernandez, Melanie; Harwood, Michelle; Hou, Wei; Garvan, Cynthia Wilson; Eyberg, Sheila M.; Swanson, James M.

    2008-01-01

    To examine Swanson, Nolan, and Pelham-IV (SNAP-IV) psychometric properties, parent (N = 1,613) and teacher (N = 1,205) data were collected from a random elementary school student sample in a longitudinal attention deficit hyperactivity disorder (ADHD) detection study. SNAP-IV reliability was acceptable. Factor structure indicated two ADHD factors…

  11. Vibration Test of a SNAP-8 Sodium-Potassium Alloy Pump

    NASA Image and Video Library

    1970-01-21

    Aeronautics and Space Administration (NASA) Lewis Research Center. Aerojet General was contracted to design the SNAP-8 generator which employed a mercury Rankine system to convert the reactor’s heat into electrical power. The hermetically-sealed pump was designed to generate from 35 to 90 kilowatts of electrical power. In 1964 a SNAP-8 test rig with a mercury boiler and condenser was set up in cell W-1 of Lewis’ Engine Research Building to study the transients in the system’s three loops. In 1967 a complete Rankine system was operated for 60 days in W-1 to verify the integrity of the Lewis-developed mercury boiler. Further tests in 1969 verified the shutdown and startup of the system under normal and emergency conditions. Aerojet operated the first full-Rankine system in June 1966 and completed a 2500-hour endurance test in early 1969. Lewis and Aerojet’s success on the Rankine system was acknowledged with NASA Group Achievement Award in November 1970. The 1970 vibration tests, seen here, were conducted in Lewis’ Engine Research Building’s environmental laboratory. The testing replicated the shock and vibration expected to occur during the launch into space and subsequent maneuvering. The pump was analyzed on each of its major axes.

  12. Mercury concentrations in snapping turtles (Chelydra serpentina) correlate with environmental and landscape characteristics.

    PubMed

    Turnquist, Madeline A; Driscoll, Charles T; Schulz, Kimberly L; Schlaepfer, Martin A

    2011-10-01

    Mercury (Hg) deposited onto the landscape can be transformed into methylmercury (MeHg), a neurotoxin that bioaccumulates up the aquatic food chain. Here, we report on Hg concentrations in snapping turtles (Chelydra serpentina) across New York State, USA. The objectives of this study were to: (1) test which landscape, water, and biometric characteristics correlate with total Hg (THg) concentrations in snapping turtles; and (2) determine whether soft tissue THg concentrations correlate with scute (shell) concentrations. Forty-eight turtles were sampled non-lethally from ten lakes and wetlands across New York to observe patterns under a range of ecosystem variables and water chemistry conditions. THg concentrations ranged from 0.041 to 1.50 μg/g and 0.47 to 7.43 μg/g wet weight of muscle tissue and shell, respectively. The vast majority of mercury (~94%) was in the MeHg form. Sixty-one percent of turtle muscle samples exceeded U.S. Environmental Protection Agency (U.S. EPA) consumption advisory limit of 0.3 μg Hg/g for fish. Muscle THg concentrations were significantly correlated with sulfate in water and the maximum elevation of the watershed. Shell THg concentrations were significantly correlated with the acid neutralizing capacity (ANC) of water, the maximum elevation of the watershed, the percent open water in the watershed, the lake to watershed size, and various forms of atmospheric Hg deposition. Thus, our results demonstrate that THg concentrations in snapping turtles are spatially variable, frequently exceed advisory limits, and are significantly correlated with several landscape and water characteristics.

  13. Rapid acceleration of outer radiation belt electrons associated with solar wind pressure pulse: Simulation study with Arase and Van Allen Probe observations

    NASA Astrophysics Data System (ADS)

    Hayashi, M.; Yoshizumi, M.; Saito, S.; Matsumoto, Y.; Kurita, S.; Teramoto, M.; Hori, T.; Matsuda, S.; Shoji, M.; Machida, S.; Amano, T.; Seki, K.; Higashio, N.; Mitani, T.; Takashima, T.; Kasahara, Y.; Kasaba, Y.; Yagitani, S.; Ishisaka, K.; Tsuchiya, F.; Kumamoto, A.; Matsuoka, A.; Shinohara, I.; Blake, J. B.; Fennell, J. F.; Claudepierre, S. G.

    2017-12-01

    Relativistic electron fluxes of the outer radiation belt rapidly change in response to solar wind variations. One of the shortest acceleration processes of electrons in the outer radiation belt is wave-particle interactions between drifting electrons and fast-mode waves induced by compression of the dayside magnetopause caused by interplanetary shocks. In order to investigate this process by a solar wind pressure pulse, we perform a code-coupling simulation using the GEMSIS-RB test particle simulation (Saito et al., 2010) and the GEMSIS-GM global MHD magnetosphere simulation (Matsumoto et al., 2010). As a case study, an interplanetary pressure pulse with the enhancement of 5 nPa is used as the up-stream condition. In the magnetosphere, the fast mode waves with the azimuthal electric field ( negative 𝐸𝜙 : |𝐸&;#120601;| 10 mV/m, azimuthal mode number : m ≤ 2) propagates from the dayside to nightside, interacting with electrons. From the simulation results, we derived effective acceleration model and condition : The electrons whose drift velocities vd ≥ (π/2)Vfast are accelerated efficiently. On December 20, 2016, the Arase (ERG) satellite was launched , allowing more accurate multi-point simultaneous observation with other satellites. We will compare our simulation results with observations from Arase and Van Allen Probes, and investigate the acceleration condition of relativistic electrons associated with storm sudden commencement (SSC).

  14. SNAP-Ed (Supplemental Nutrition Assistance Program-Education) Increases Long-Term Food Security among Indiana Households with Children in a Randomized Controlled Study.

    PubMed

    Rivera, Rebecca L; Maulding, Melissa K; Abbott, Angela R; Craig, Bruce A; Eicher-Miller, Heather A

    2016-11-01

    Food insecurity is negatively associated with US children's dietary intake and health. The Supplemental Nutrition Assistance Program-Education (SNAP-Ed) aims to alleviate food insecurity by offering nutrition, budgeting, and healthy lifestyle education to low-income individuals and families. The objective of this study was to evaluate the long-term impact of the Indiana SNAP-Ed on food security among households with children. A randomized, controlled, parallel study design with SNAP-Ed as an intervention was carried out during a 4- to 10-wk intervention period. Intervention group participants received the first 4 Indiana SNAP-Ed curriculum lessons. Study participants (n = 575) were adults aged ≥18 y from low-income Indiana households with ≥1 child living in the household. Both treatment groups completed an assessment before and after the intervention period and 1 y after recruitment. The 18-item US Household Food Security Survey Module was used to classify the primary outcomes of food security for the household and adults and children in the household. A linear mixed model was used to compare intervention with control group effects over time on food security. Mean ± SEM changes in household food security score and food security score among household adults from baseline to 1-y follow-up were 1.2 ± 0.4 and 0.9 ± 0.3 units lower, respectively, in the intervention group than in the control group (P < 0.01). The mean change in food security score from baseline to 1-y follow-up among household children was not significantly different in the intervention group compared with the control group. SNAP-Ed improved food security over a longitudinal time frame among low-income Indiana households with children in this study. SNAP-Ed may be a successful intervention to improve food security. © 2016 American Society for Nutrition.

  15. Development of a mercury electromagnetic centrifugal pump for the SNAP-8 refractory boiler development program

    NASA Technical Reports Server (NTRS)

    Fuller, R. A.; Schnacke, A. W.

    1974-01-01

    An electromagnetic pump, in which pressure is developed in mercury because of the interaction of the magnetic field and current which flows as a result of the voltage induced in the mercury contained in the pump duct, was developed for the SNAP-8 refractory boiler test facility. Pump performance results are presented for ten duct configurations and two stator sizes. These test results were used to design and fabricate a pump which met the SNAP-8 criteria of 530 psi developed pressure at 12,500 lb/hr. The pump operated continuously for over 13,000 hours without failure or performance degradation. Included in this report are descriptions of the experimental equipment, measurement techniques, all experimental data, and an analysis of the electrical losses in the pump.

  16. Effects of environmental contaminants on snapping turtles of a tidal wetland

    USGS Publications Warehouse

    Albers, P.H.; Sileo, L.; Mulhern, B.M.

    1986-01-01

    Snapping turtles (Chelydra serpentina) were collected from a brackish-water and a nearly freshwater area in the contaminated Hackensack Meadowlands of New Jersey and an uncontaminated freshwater area in Maryland to determine the effects of environmental contaminants on a resident wetland species. No turtles were observed or caught in the Meadowlands at two trapping sites that were the most heavily contaminated by metals. Snapping turtles from the brackish-water area had an unusually low lipid content of body fat and reduced growth compared to turtles from the fresh-water areas in New Jersey and Maryland. Despite the serious metal contamination of the Hackensack Meadowlands, the metal content of kidneys and livers from New Jersey turtles was low and not greatly different from that of the Maryland turtles. Organochlorine pesticide concentrations in body fat were generally low at all three study areas. Polychlorinated biphenyls (PCBs) concentrations in fat were highest in male turtles from the New Jersey brackish-water area. Analysis of blood for amino-levulinic acid dehydratase, albumin, glucose, hemoglobin, osmolality, packed cell volume, total protein, triglycerides, and uric acid failed to reveal any differences among groups that would indicate physiological impairment related to contaminants.

  17. Aligning the magnetic field of a linear induction accelerator with a low-energy electron beam

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

    Clark, J.C.; Deadrick, F.J.; Kallman, J.S.

    1989-03-10

    The Experimental Test Accelerator II (ETA-II) linear induction accelerator at Lawrence Livermore National Laboratory uses a solenoid magnet in each acceleration cell to focus and transport an electron beam over the length of the accelerator. To control growth of the corkscrew mode the magnetic field must be precisely aligned over the full length of the accelerate. Concentric with each solenoid magnet is sine/cosmic-wound correction coil to steer the beam and correct field errors. A low-energy electron probe traces the central flux line through the accelerator referenced to a mechanical axis that is defined by a copropagating laser beam. Correction coilsmore » are activated to force the central flux line to cross the mechanical axis at the end of each acceleration cell. The ratios of correction coil currents determined by the low-energy electron probe are then kept fixed to correct for field errors during normal operation with an accelerated beam. We describe the construction of the low-energy electron probe and report the results of experiments we conducted to measure magnetic alignment with and without the correction coils activated. 5 refs., 3 figs.« less

  18. The effects of stressful stimuli and hypothalamic-pituitary-adrenal axis activation are reversed by the melanin-concentrating hormone 1 receptor antagonist SNAP 94847 in rodents.

    PubMed

    Smith, Daniel G; Hegde, Laxminarayan G; Wolinsky, Toni D; Miller, Silke; Papp, Mariusz; Ping, Xiaoli; Edwards, Tanya; Gerald, Christophe P; Craig, Douglas A

    2009-02-11

    Melanin-concentrating hormone (MCH) is an orexigenic and dipsogenic neuropeptide that has been reported to mediate acute behavioral and neuroendocrine stress-related responses via MCH(1) receptor activation in rodents. The purpose of the present investigation was to use the MCH(1) receptor antagonist SNAP 94847 (N-(3-{1-[4-(3,4-difluoro-phenoxy)-benzyl]-piperidin-4-yl}-4-methyl-phenyl)-isobutyramide) to determine the effects of MCH(1) receptor blockade on MCH-evoked adrenocorticotropic hormone (ACTH) release, chronic mild stress-induced anhedonia, stress-induced hyperthermia and forced swim stress-induced immobility. The appropriate dose range for testing SNAP 94847 was determined by measuring MCH-evoked water drinking. The corresponding occupancy of MCH(1) receptors in rat striatum was also measured across a broad dose range. Orally administered (p.o.) SNAP 94847 (1-10 mg/kg) corresponds to 30-60% occupancy at MCH(1) receptors and significantly blocks water drinking induced by the intracerebroventricular (i.c.v.) injection of MCH. MCH (i.c.v.) significantly elevates plasma levels of ACTH in rats, and SNAP 94847 (2.5 mg/kg, p.o.) blocks MCH-evoked ACTH release. Using the chronic mild stress paradigm, we show that repeated daily exposure to environmental stressors for 5 weeks significantly suppresses sucrose intake in rats, and that SNAP 94847 (1 mg/kg, BID) for 1-5 weeks restores baseline sucrose intake. Moreover, a single administration of SNAP 94847 attenuates stress-induced hyperthermia and the behavioral effects of forced swim stress with minimal effective doses of 2.5 and 30 mg/kg (p.o.), respectively. The regulation of ACTH release and reversal of the effects of chronic and acute stress by SNAP 94847 are suggestive of a role for MCH(1) receptor blockade in the treatment of disorders characterized by high allostatic load.

  19. Variation among edible podded snap bean accessions for pod and seed sugar content

    USDA-ARS?s Scientific Manuscript database

    Sugar content of immature snap bean (Phaseolus vulgaris) pods and the effects of sugars on other flavor compounds are important to consumers and affect their food and vegetable choices. The objective of this study was to identify variation within Phaseolus vulgaris in relation to sugars that affect ...

  20. Solar Probe Plus: A NASA Mission to Touch the Sun

    NASA Astrophysics Data System (ADS)

    Fox, N. J.; Bale, S. D.; Decker, R. B.; Howard, R.; Kasper, J. C.; McComas, D. J.; Szabo, A.; Velli, M. M.

    2013-12-01

    Solar Probe Plus (SPP), currently in Phase B, will be the first mission to fly into the low solar corona, revealing how the corona is heated and the solar wind is accelerated, solving two fundamental mysteries that have been top priority science goals since such a mission was first proposed in 1958. The scale and concept of such a mission has been revised at intervals since that time, yet the core has always been a close encounter with the Sun. The primary science goal of the Solar Probe Plus mission is to determine the structure and dynamics of the Sun's coronal magnetic field, understand how the solar corona and wind are heated and accelerated, and determine what mechanisms accelerate and transport energetic particles. The SPP mission will achieve this by identifying and quantifying the basic plasma physical processes at the heart of the Heliosphere. SPP uses an innovative mission design, significant technology development and a risk-reducing engineering development to meet the SPP science objectives: 1) Trace the flow of energy that heats and accelerates the solar corona and solar wind; 2) Determine the structure and dynamics of the plasma and magnetic fields at the sources of the solar wind; and 3) Explore mechanisms that accelerate and transport energetic particles. In this poster, we present Solar Probe Plus and examine how the mission will address the science questions that have remained unanswered for over 5 decades.

  1. Solar Probe Plus: A NASA Mission to Touch the Sun

    NASA Astrophysics Data System (ADS)

    Fox, N. J.; Velli, M. M. C.; Kasper, J. C.; McComas, D. J.; Howard, R.; Bale, S. D.; Decker, R. B.

    2014-12-01

    Solar Probe Plus (SPP), currently in Phase C, will be the first mission to fly into the low solar corona, revealing how the corona is heated and the solar wind and energetic particles are accelerated, solving fundamental mysteries that have been top priority science goals since such a mission was first proposed in 1958. The scale and concept of such a mission has been revised at intervals since that time, yet the core has always been a close encounter with the Sun. The primary science goal of the Solar Probe Plus mission is to determine the structure and dynamics of the Sun's coronal magnetic field, understand how the solar corona and wind are heated and accelerated, and determine what mechanisms accelerate and transport energetic particles. The SPP mission will achieve this by identifying and quantifying the basic plasma physical processes at the heart of the Heliosphere. SPP uses an innovative mission design, significant technology development and a risk-reducing engineering development to meet the SPP science objectives: 1) Trace the flow of energy that heats and accelerates the solar corona and solar wind; 2) Determine the structure and dynamics of the plasma and magnetic fields at the sources of the solar wind; and 3) Explore mechanisms that accelerate and transport energetic particles. In this presentation, we present Solar Probe Plus and examine how the mission will address the science questions that have remained unanswered for over 5 decades.

  2. A dielectric elastomer actuator coupled with water: snap-through instability and giant deformation

    NASA Astrophysics Data System (ADS)

    Godaba, Hareesh; Foo, Choon Chiang; Zhang, Zhi Qian; Khoo, Boo Cheong; Zhu, Jian

    2015-04-01

    A dielectric elastomer actuator is one class of soft actuators which can deform in response to voltage. Dielectric elastomer actuators coupled with liquid have recently been developed as soft pumps, soft lenses, Braille displays, etc. In this paper, we conduct experiments to investigate the performance of a dielectric elastomer actuator which is coupled with water. The membrane is subject to a constant water pressure, which is found to significantly affect the electromechanical behaviour of the membrane. When the pressure is small, the membrane suffers electrical breakdown before snap-through instability, and achieves a small voltage-induced deformation. When the pressure is higher to make the membrane near the verge of the instability, the membrane can achieve a giant voltage-induced deformation, with an area strain of 1165%. When the pressure is large, the membrane suffers pressure-induced snap-through instability and may collapse due to a large amount of liquid enclosed by the membrane. Theoretical analyses are conducted to interpret these experimental observations.

  3. Snapping turtles (Chelydra serpentina) as biomonitors of lead contamination of the Big River in Missouri`s Old Lead Belt

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

    Overmann, S.R.; Krajicek, J.J.

    1995-04-01

    The usefulness of common snapping turtles (Chelydra serpentina) as biomonitors of lead (Pb) contamination of aquatic ecosystems was assessed. Thirty-seven snapping turtles were collected from three sites on the Big River, an Ozarkian stream contaminated with Pb mine tailings. Morphometric measurements, tissue Pb concentrations (muscle, blood, bone, carapace, brain, and liver), {delta}-aminolevulinic acid dehydratase ({delta}-ALAD) activity, hematocrit, hemoglobin, plasma glucose, osmolality, and chloride ion content were measured. The data showed no effects of Pb contamination on capture success or morphological measurements. Tissue Pb concentrations were related to capture location. Hematocrit, plasma osmolality, plasma glucose, and plasma chloride ion content weremore » not significantly different with respect to capture location. The {delta}-ALAD activity levels were decreased in turtles taken from contaminated sites. Lead levels in the Big River do not appear to be adversely affecting the snapping turtles of the river. Chelydra serpentina is a useful species for biomonitoring of Pb-contaminated aquatic environments.« less

  4. Validation of questionnaire on the Spiritual Needs Assessment for Patients (SNAP) questionnaire in Brazilian Portuguese

    PubMed Central

    de Araujo Toloi, Diego; Uema, Deise; Matsushita, Felipe; da Silva Andrade, Paulo Antonio; Branco, Tiago Pugliese; de Carvalho Chino, Fabiana Tomie Becker; Guerra, Raquel Bezerra; Pfiffer, Túlio Eduardo Flesch; Chiba, Toshio; Guindalini, Rodrigo Santa Cruz; Sulmasy, Daniel P; Riechelmann, Rachel P

    2016-01-01

    Summary Objectives Spirituality is related to the care and the quality of life of cancer patients. Thus, it is very important to assess their needs. The objective of this study was the translation and cultural adjustment of the Spiritual Needs Assessment for Patients (SNAP) questionnaire to the Brazilian Portuguese language. Methodology The translation and cultural adjustment of the SNAP questionnaire involved six stages: backtranslation, revision of backtranslation, translation to the original language and adjustments, pre-test on ten patients, and test and retest with 30 patients after three weeks. Adult patients, with a solid tumour and literate with a minimum of four years schooling were included. For analysis and consistency we used the calculation of the Cronbach alpha coefficient and the Pearson linear correlation. Results The final questionnaire had some language and content adjustments compared to the original version in English. The correlation analysis of each item with the total score of the questionnaire showed coefficients above 0.99. The calculation of the Cronbach alpha coefficient was 0.9. The calculation of the Pearson linear correlation with the test and retest of the questionnaire was equal to 0.95. Conclusion The SNAP questionnaire translated into Brazilian Portuguese is adequately reliable and consistent. This instrument allows adequate access to spiritual needs and can help patient care. PMID:28101137

  5. Recent Progress on Understanding SEP Acceleration and Transport

    NASA Astrophysics Data System (ADS)

    Cohen, C.

    2017-12-01

    Joint observations between near-Earth spacecraft and the twin STEREO spacecraft have allowed new examinations of the longitudinal extent of solar energetic particles (SEPs). Although the radial dependence will not be measured in detail until Parker Solar Probe and Solar Orbiter have launched, recent developments in modeling SEP acceleration and transport have revealed interesting dependences on magnetic field configurations and the characteristics of seed particle populations. This talk will review recent SEP in-situ observations along with theoretical studies and their implications for our understanding of SEP acceleration and transport in the inner heliosphere and our expectations for upcoming Solar Orbiter and Parker Solar Probe observations.

  6. Preliminary tests of the electrostatic plasma accelerator

    NASA Technical Reports Server (NTRS)

    Aston, G.; Acker, T.

    1990-01-01

    This report describes the results of a program to verify an electrostatic plasma acceleration concept and to identify those parameters most important in optimizing an Electrostatic Plasma Accelerator (EPA) thruster based upon this thrust mechanism. Preliminary performance measurements of thrust, specific impulse and efficiency were obtained using a unique plasma exhaust momentum probe. Reliable EPA thruster operation was achieved using one power supply.

  7. Niobium tunnel junction fabrication using e-gun evaporation and SNAP

    NASA Astrophysics Data System (ADS)

    Kortlandt, J.; van der Zant, H. S. J.; Schellingerhout, A. J. G.; Mooij, J. E.

    1990-11-01

    We have fabricated high quality small area Nb-Al-Al 2O 3-Nb junctions with SNAP, making use of e-beam evaporation in a 10 -5 Pa diffusion pumped vacuum system. Nominal dimensions of the junctions are 8x8, 4x4 and 2x2 μm 2. We obtain typical current densities of 5-6 × 10 +2A/cm 2 and (critical current) x (subgap resistance) products of 40 mV.

  8. Measurements and simulation of liquid films during drainage displacements and snap-off in constricted capillary tubes.

    PubMed

    Roman, Sophie; Abu-Al-Saud, Moataz O; Tokunaga, Tetsu; Wan, Jiamin; Kovscek, Anthony R; Tchelepi, Hamdi A

    2017-12-01

    When a wetting liquid is displaced by air in a capillary tube, a wetting film develops between the tube wall and the air that is responsible for the snap-off mechanism of the gas phase. By dissolving a dye in the wetting phase it is possible to relate a measure of the absorbance in the capillary to the thickness of liquid films. These data could be used to compare with cutting edge numerical simulations of the dynamics of snap-off for which experimental and numerical data are lacking. Drainage experiments in constricted capillary tubes were performed where a dyed wetting liquid is displaced by air for varying flow rates. We developed an optical method to measure liquid film thicknesses that range from 3 to 1000μm. The optical measures are validated by comparison with both theory and direct numerical simulations. In a constricted capillary tube we observed, both experimentally and numerically, a phenomenon of snap-off coalescence events in the vicinity of the constriction that bring new insights into our understanding and modeling of two-phase flows. In addition, the good agreement between experiments and numerical simulations gives confidence to use the numerical method for more complex geometries in the future. Copyright © 2017 Elsevier Inc. All rights reserved.

  9. Insecticide Efficacy and Timing for Control of Western Bean Cutworm (Lepidoptera: Noctuidae) in Dry and Snap Beans.

    PubMed

    Goudis, L A; Trueman, C L; Baute, T S; Hallett, R H; Gillard, C L

    2016-02-01

    The western bean cutworm, Striacosta albicosta (Smith) (Lepidoptera: Noctuidae), is a recent pest of corn, dry,and snap beans, in the Great Lakes region, and best practices for its management in beans need to be established.Insecticide efficacy and application timing field studies, conducted in 2011–2013, determined that lambda-cyhalothrin and chlorantraniliprole were capable of reducing western bean cutworm feeding damage in dry beans from 2.3 to 0.4% in preharvest samples, and in snap beans from 4.8 to 0.1% of marketable pods, respectively. The best application timing in dry beans was determined to be 4–18 d after 50% egg hatch. No economic benefit was found when products were applied to dry beans, and despite high artificial inoculation rates, damage to marketable yield was relatively low. Thiamethoxam, methoxyfenozide, and spinetoram were also found to be effective at reducing western bean cutworm damage in dry bean to as low as 0.3% compared to an untreated control with 2.5% damaged pods. In snap beans, increased return on investment between CAD$400 and CAD$600 was seen with multiple applications of lambda-cyhalothrin, and with chlorantraniliprole applied 4 d after egg mass infestation.

  10. Estimating E-Race European Corn Borer (Lepidoptera: Crambidae) Adult Activity in Snap Bean Fields Based on Corn Planting Intensity and Their Activity in Corn in New York Agroecosystems.

    PubMed

    Schmidt-Jeffris, Rebecca A; Huseth, Anders S; Nault, Brian A

    2016-07-24

    European corn borer, Ostrinia nubilalis (Hübner), is a major pest of processing snap bean because larvae are contaminants in pods. The incidence of O. nubilalis-contaminated beans has become uncommon in New York, possibly because widespread adoption of Bt field corn has suppressed populations. Snap bean fields located where Bt corn has been intensively grown in space and time may be at lower risk for O. nubilalis than fields located where Bt corn is not common. To manage O. nubilalis infestation risk, growers determine insecticide application frequency in snap bean based on pheromone-trapping information in nearby sweet corn fields; adult activity is presumed equivalent in both crops. Our goal was to determine if corn planting intensity and adult activity in sweet corn could be used to estimate O. nubilalis populations in snap bean in New York in 2014-2015. Numbers of O nubilalis adults captured in pheromone-baited traps located in snap bean fields where corn was and was not intensively grown were similar, suggesting that O. nubilalis does not respond to local levels of Bt corn in the landscape. Numbers of Ostrinia nubilalis captured in pheromone-baited traps placed by snap bean fields and proximal sweet corn fields were not related, indicating that snap bean growers should no longer make control decisions based on adult activity in sweet corn. Our results also suggest that the risk of O. nubilalis infestations in snap bean is low (∼80% of the traps caught zero moths) and insecticide applications targeting this pest should be reduced or eliminated. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  11. Amelogenesis Imperfecta, Facial Esthetics and Snap-On Smile.

    PubMed

    Wilson, Lee; Bradshaw, Jonathan P; Marks, Murray K

    2015-01-01

    Amelogenesis imperfecta is a hereditary enamel protein disorder affecting deciduous and secondary crown formation. The prevalence ranges from 1:700 to 1:14,000 depending on the population. These teeth may be hypoplastic, hypomineralized, or hypermineralized and are often discolored, sensitive and caries vulnerable. Patients often present with psychosocial issues due to appearance. Primary teeth are often treated with stainless steel crowns while secondary teeth are treated with full coverage esthetic crowns. The presenting preteen male here was fitted with Snap-On Smile? (www.snaponsmile.com). This treatment option provided cosmetic enhancement of the patient's appearance besides stabilization without altering the primary and secondary dentition during adolescent development.

  12. SNAP 19 Pioneer F and G. Final Report

    DOE R&D Accomplishments Database

    1973-06-01

    The generator developed for the Pioneer mission evolved from the SNAP 19 RTG`s launched aboard the NIMBUS III spacecraft. In order to satisfy the power requirements and environment of earth escape trajectory, significant modifications were made to the thermoelectric converter, heat source, and structural configuration. Specifically, a TAGS 2N thermoelectric couple was designed to provide higher efficiency and improved long term power performance, and the electrical circuitry was modified to yield very low magnetic field from current flow in the RTG. A new heat source was employed to satisfy operational requirements and its integration with the generator required alteration to the method of providing support to the fuel capsule.

  13. Experimental Nonlinear Dynamics and Snap-Through of Post-Buckled Thin Laminated Composite Plates

    NASA Astrophysics Data System (ADS)

    Kim, Han-Gyu

    Modern aerospace systems are increasingly being designed with composite panels and plates to achieve light weight and high specific strength and stiffness. For constrained panels, thermally-induced axial loading may cause buckling of the structure, which can lead to nonlinear and potentially chaotic behavior. When post-buckled composite plates experience snap-through, they are subjected to large-amplitude deformations and in-plane compressive loading. These phenomena pose a potential threat to the structural integrity of composite structures. In this work, the nonlinear dynamic behavior of post-buckled composite plates was investigated experimentally and computationally. For the experimental work, an electrodynamic shaker was used to apply harmonic loads and the dynamic response of plate specimens was measured using a single-point displacement-sensing laser, a double-point laser vibrometer (velocity-sensing), and a set of digital image correlation cameras. Both chaotic and periodic steady-state snap-through behaviors were investigated. The experimental data were used to characterize snap-through behaviors of the post-buckled specimens and their boundaries in the harmonic forcing parameter space. The nonlinear behavior of post-buckled plates was modeled using the classical laminated plate theory (CLPT) and the von Karman strain-displacement relations. The static equilibrium paths of the post-buckled plates were analyzed using an arc-length method with a branch-switching technique. For the dynamic analysis, the nonlinear equations of motion were derived based on CLPT and the nonlinear finite element model of the equations was constructed using the Hermite cubic interpolation functions for both conforming and nonconforming elements. The numerical analyses were conducted using the model and were compared with the experimental data.

  14. Interpretation of plasma impurity deposition probes. Analytic approximation

    NASA Astrophysics Data System (ADS)

    Stangeby, P. C.

    1987-10-01

    Insertion of a probe into the plasma induces a high speed flow of the hydrogenic plasma to the probe which, by friction, accelerates the impurity ions to velocities approaching the hydrogenic ion acoustic speed, i.e., higher than the impurity ion thermal speed. A simple analytic theory based on this effect provides a relation between impurity fluxes to the probe Γimp and the undisturbed impurity ion density nimp, with the hydrogenic temperature and density as input parameters. Probe size also influences the collection process and large probes are found to attract a higher flux density than small probes in the same plasma. The quantity actually measured, cimp, the impurity atom surface density (m-2) net-deposited on the probe, is related to Γimp and thus to nimp by taking into account the partial removal of deposited material caused by sputtering and the redeposition process.

  15. Snap-, CLIP- and Halo-Tag Labelling of Budding Yeast Cells

    PubMed Central

    Stagge, Franziska; Mitronova, Gyuzel Y.; Belov, Vladimir N.; Wurm, Christian A.; Jakobs, Stefan

    2013-01-01

    Fluorescence microscopy of the localization and the spatial and temporal dynamics of specifically labelled proteins is an indispensable tool in cell biology. Besides fluorescent proteins as tags, tag-mediated labelling utilizing self-labelling proteins as the SNAP-, CLIP-, or the Halo-tag are widely used, flexible labelling systems relying on exogenously supplied fluorophores. Unfortunately, labelling of live budding yeast cells proved to be challenging with these approaches because of the limited accessibility of the cell interior to the dyes. In this study we developed a fast and reliable electroporation-based labelling protocol for living budding yeast cells expressing SNAP-, CLIP-, or Halo-tagged fusion proteins. For the Halo-tag, we demonstrate that it is crucial to use the 6′-carboxy isomers and not the 5′-carboxy isomers of important dyes to ensure cell viability. We report on a simple rule for the analysis of 1H NMR spectra to discriminate between 6′- and 5′-carboxy isomers of fluorescein and rhodamine derivatives. We demonstrate the usability of the labelling protocol by imaging yeast cells with STED super-resolution microscopy and dual colour live cell microscopy. The large number of available fluorophores for these self-labelling proteins and the simplicity of the protocol described here expands the available toolbox for the model organism Saccharomyces cerevisiae. PMID:24205303

  16. Changes in mesenteric, renal, and aortic flows with +Gx acceleration

    NASA Technical Reports Server (NTRS)

    Stone, H. L.; Erickson, H. H.; Sandler, H.

    1974-01-01

    Previous studies in man and dogs have indicated that the splanchnic bed might contribute to the maintenance of arterial pressure during +Gx acceleration. Eight mongrel dogs were chronically instrumented with Doppler flow probes around the superior mesenteric (SMA) and renal arteries (RA) as well as the terminal aorta (TA). A solid-state pressure transducer was placed in the aorta distal to the flow probe. Using alpha-chloralose anesthesia following a 2-4 week recovery period, the animals were subjected to 120 sec at levels of 5, 10 and 15 +Gx acceleration on a 7.6-m radius centrifuge. The results indicate that both an active component and a mechanical component contribute to the maintenance of arterial pressure during +Gx acceleration.

  17. Examining Internet Access and Social Media Application Use for Online Nutrition Education in SNAP-Ed Participants in Rural Illinois.

    PubMed

    Loehmer, Emily; Smith, Sylvia; McCaffrey, Jennifer; Davis, Jeremy

    2018-01-01

    To examine Internet access and interest in receiving nutrition education via social media applications among low-income adults participating in the Supplemental Nutrition Assistance Program Education (SNAP-Ed). A cross-sectional survey was distributed during 25 SNAP-Ed classes throughout the 16 southernmost counties of Illinois. From 188 responses, the majority of participants had Internet access (76%). Among participants aged 18-32 years (n = 51), 92% owned a smartphone with Internet access and 57% indicated that they would use online nutrition education, with most interest in e-mail (41%), Facebook (40%), and text messaging (35%). There was little interest in using blogs, Vine, Twitter, Tumblr, and Pinterest. Overall, 49% of middle-aged adults aged 33-64 years and 87% of seniors aged ≥65 years reported they would not use online nutrition education. Results indicated similar Internet accessibility in southern Illinois among low-income populations compared with national rural rates. Interest in using online nutrition education varied among SNAP-Ed participants according to age. Young adults appeared to be the most captive audience regarding online nutrition education. Results may be useful to agencies implementing SNAP-Ed to supplement current curriculum with online nutrition education for audiences aged ≤32 years. Copyright © 2017 Society for Nutrition Education and Behavior. Published by Elsevier Inc. All rights reserved.

  18. SnAP reagents for the one-step synthesis of medium-ring saturated N-heterocycles from aldehydes

    NASA Astrophysics Data System (ADS)

    Vo, Cam-Van T.; Luescher, Michael U.; Bode, Jeffrey W.

    2014-04-01

    Interest in saturated N-heterocycles as scaffolds for the synthesis of bioactive molecules is increasing. Reliable and predictable synthetic methods for the preparation of these compounds, especially medium-sized rings, are limited. We describe the development of SnAP (Sn amino protocol) reagents for the transformation of aldehydes into seven-, eight- and nine-membered saturated N-heterocycles. This process occurs under mild, room-temperature conditions and offers exceptional substrate scope and functional-group tolerance. Air- and moisture-stable SnAP reagents are prepared on a multigram scale from inexpensive starting materials by simple reaction sequences. These new reagents and processes allow widely available aryl, heteroaryl and aliphatic aldehydes to be converted into diverse N-heterocycles, including diazepanes, oxazepanes, diazocanes, oxazocanes and hexahydrobenzoxazonines, by a single synthetic operation.

  19. Arc-driven rail accelerator research

    NASA Technical Reports Server (NTRS)

    Ray, Pradosh K.

    1987-01-01

    Arc-driven rail accelerator research is analyzed by considering wall ablation and viscous drag in the plasma. Plasma characteristics are evaluated through a simple fluid-mechanical analysis considering only wall ablation. By equating the energy dissipated in the plasma with the radiation heat loss, the average properties of the plasma are determined as a function of time and rate of ablation. Locations of two simultaneously accelerating arcs were determined by optical and magnetic probes and fron streak camera photographs. All three measurements provide consistent results.

  20. The Spiritual Needs Assessment for Patients (SNAP): development and validation of a comprehensive instrument to assess unmet spiritual needs.

    PubMed

    Sharma, Rashmi K; Astrow, Alan B; Texeira, Kenneth; Sulmasy, Daniel P

    2012-07-01

    Unmet spiritual needs have been associated with decreased patient ratings of quality of care, satisfaction, and quality of life. There is a need for a well-validated, psychometrically sound instrument to describe and measure spiritual needs. To develop a valid and reliable instrument to assess patients' spiritual needs. Instrument development was based on a literature review, clinical and pastoral evaluation, and cognitive pretesting (n=15 ambulatory cancer patients). Forty-seven ambulatory cancer patients completed cross-sectional and longitudinal surveys to test instrument validity and reliability. Internal reliability was assessed by Cronbach's α, test-retest reliability by Spearman's correlation coefficients, and construct validity by comparing instrument scores to a previously used single-item spiritual needs question. The Spiritual Needs Assessment for Patients (SNAP) comprises a total of 23 items in three domains: psychosocial (n=5), spiritual (n=13), and religious (n=5). Sixty percent of participants were white, 21% black, 13% Hispanic, and 6% Asian or other. Fifty-eight percent were Catholic, 13% Jewish, 11% Protestant, 2% Buddhist, 2% Muslim, and 2% Hindu. Sixty-eight percent described themselves as spiritual but not religious; 15% reported unmet spiritual needs; 19% wanted help meeting their spiritual needs. Cronbach's α for the total SNAP was 0.95, and for the subscales was psychosocial=0.74, spiritual=0.93, and religious needs=0.86. Test-retest correlation coefficients were total SNAP=0.69, psychosocial needs=0.51, spiritual needs=0.70, and religious needs=0.65. Participants reporting unmet spiritual needs had significantly higher mean scores on the total SNAP (66.3 vs. 49.4, P=0.03) and on the spiritual needs subscale (39.0 vs. 28.3, P=0.02). The results provide preliminary evidence that the SNAP is a valid and reliable instrument for measuring spiritual needs in a diverse patient population. Copyright © 2012 U.S. Cancer Pain Relief Committee

  1. ApoE and SNAP-25 Polymorphisms Predict the Outcome of Multidimensional Stimulation Therapy Rehabilitation in Alzheimer's Disease.

    PubMed

    Guerini, Franca Rosa; Farina, Elisabetta; Costa, Andrea Saul; Baglio, Francesca; Saibene, Francesca Lea; Margaritella, Nicolò; Calabrese, Elena; Zanzottera, Milena; Bolognesi, Elisabetta; Nemni, Raffaello; Clerici, Mario

    2016-10-01

    Alzheimer's disease (AD) is a highly prevalent neurodegenerative disorder. Rate of decline and functional restoration in AD greatly depend on the capacity for neural plasticity within residual neural tissues; this is at least partially influenced by polymorphisms in genes that determine neural plasticity, including Apolipoprotein E4 (ApoE4) and synaptosomal-associated protein of 25 kDa (SNAP-25). We investigated whether correlations could be detected between polymorphisms of ApoE4 and SNAP-25 and the outcome of a multidimensional rehabilitative approach, based on cognitive stimulation, behavioral, and functional therapy (multidimensional stimulation therapy [MST]). Fifty-eight individuals with mild-to-moderate AD underwent MST for 10 weeks. Neuro-psychological functional and behavioral evaluations were performed blindly by a neuropsychologist at baseline and after 10 weeks of therapy using Mini-Mental State Examination (MMSE), Functional Living Skill Assessment (FLSA), and Neuropsychiatric Inventory (NPI) scales. Molecular genotyping of ApoE4 and SNAP-25 rs363050, rs363039, rs363043 was performed. Results were correlated with ΔMMSE, ΔNPI and ΔFLSA scores by multinomial logistic regression analysis. Polymorphisms in both genes correlated with the outcome of MST for MMSE and NPI scores. Thus, higher overall MMSE scores after rehabilitation were detected in ApoE4 negative compared to ApoE4 positive patients, whereas the SNAP-25 rs363050(G) and rs363039(A) alleles correlated with significant improvements in behavioural parameters. Polymorphisms in genes known to modulate neural plasticity might predict the outcome of a multistructured rehabilitation protocol in patients with AD. These data, although needing confirmation on larger case studies, could help optimizing the clinical management of individuals with AD, for example defining a more intensive treatment in those subjects with a lower likelihood of success. © The Author(s) 2016.

  2. Design and methodology of SNAP-1: a Sprint National Anaesthesia Project to measure patient reported outcome after anaesthesia.

    PubMed

    Moonesinghe, Suneetha Ramani; Walker, Eleanor Mary Kate; Bell, Madeline

    2015-01-01

    Patient satisfaction is an important metric of health-care quality. Accidental awareness under general anaesthesia (AAGA) is a serious complication of anaesthesia care which may go unrecognised in the immediate perioperative period but leads to long-term psychological harm for affected patients. The SNAP-1 study aimed to measure patient satisfaction with anaesthesia care and the incidence of AAGA, reported on direct questioning within 24 h of surgery, in a large multicentre cohort. A secondary aim of SNAP-1 was to test the effectiveness of a new network of Quality Audit and Research Coordinators in NHS anaesthetic departments, to achieve widespread study participation and high patient recruitment rates. This manuscript describes the study methodology. SNAP-1 was a prospective observational cohort study. The study protocol was approved by the National Research Ethics Service. All UK NHS hospitals with anaesthetic departments were invited to participate. Adult patients undergoing any type of non-obstetric surgery were recruited in participating hospitals on 13th and 14th May 2014. Demographic data were collected by anaesthetists providing perioperative care. Patients were then approached within 24 h of surgery to complete two questionnaires-the Bauer patient satisfaction questionnaire (to measure patient reported outcome) and the modified Brice questionnaire (to detect possible accidental awareness). Completion of postoperative questionnaires was taken as evidence of implied consent. Results were recorded on a standard patient case report form, and local investigators entered anonymised data into an electronic database for later analysis by the core research team. Preliminary analyses indicate that over 15,000 patients were recruited across the UK, making SNAP-1 the largest NIHR portfolio-adopted study in anaesthesia to date. Both descriptive and analytic epidemiological analyses will be used to answer specific questions about the patient perception of anaesthesia

  3. Oviductal morphology in relation to hormonal levels in the snapping turtle, Chelydra serpentina.

    PubMed

    Alkindi, A Y A; Mahmoud, I Y; Woller, M J; Plude, J L

    2006-02-01

    Microscopic and in situ visual observations were used to relate circulating hormone levels to morphological changes in the oviduct of the snapping turtle Chelydra serpentina throughout the ovarian cycle. Increase in levels of progesterone (P), estradiol (E2) and testosterone (T) levels coincide with an increase in number and growth of endometrial glands, luminal epithelial cells and secretory droplets throughout the oviduct. Testosterone and estradiol levels rose significantly (P < 0.05) after the May-June period and remained high throughout the rest of the summer. Progesterone levels remained stable throughout the summer, with a brief decline in July due to luteolysis. Hormonal values declined significantly (P < 0.001) at the end of the ovarian cycle in the fall. In situ visual observation of fresh oviducts at different stages of gravidity in recently ovulated turtles revealed that proteinaceous like components from the endometrial glands were released into the lumen to form fibers. The morphological features of the oviduct remained active throughout the summer months even though the snapping turtle is a monoclutch species which deposits all the eggs in late-May to mid-June. The high steroid levels correlate with and may be responsible for the secretory activity present throughout the summer and their decline correlates with change to low secretory activity in the fall. Calcium deposition accompanied by morphological changes in luminal cells are suggestive of secretory activity. In the egg-bearing turtles, uterine Ca2+ concentrations measured by flame atomic absorption spectrophotometry revealed significantly higher Ca2+ concentrations (P < 0.001) in eggs with soft shell than eggs without shell. There was a significant increase in calcium granules and proteinaceous fibers in luminal surface of the uterus during the period of eggshelling. This supports the fact that in the snapping turtle like in other reptiles, eggshelling process occurs in the uterus.

  4. PW-class laser-driven super acceleration systems in underdense plasmas

    NASA Astrophysics Data System (ADS)

    Yano, Masahiro; Zhidkov, Alexei; Kodama, Ryosuke

    2017-10-01

    Probing laser driven super-acceleration systems can be important tool to understand physics related to vacuum, space time, and particle acceleration. We show two proposals to probe the systems through Hawking-like effect using PW class lasers and x-ray free electron lasers. For that we study the interaction of ultrahigh intense laser pulses with intensity 1022 -1024 W/cm2 and underdense plasmas including ion motion and plasma radiation for the first time. While the acceleration w a0ωp /ωL in a wake is not maximal, the pulse propagation is much stable. The effect is that a constantly accelerated detector with acceleration w sees a boson's thermal bath at temperature ℏw / 2 πkB c . We present two designs for x-ray scattering from highly accelerated electrons produced in the plasma irradiated by intense laser pulses for such detection. Properly chosen observation angles enable us to distinguish spectral broadening from Doppler shift with a reasonable photon number. Also, ion motion and radiation damping on the interaction are investigated via fully relativistic 3D particle-in-cell simulation. We observe high quality electron bunches under super-acceleration when transverse plasma waves are excited by ponderomotive force producing plasma channel.

  5. Effects of Thiamethoxam-Treated Seed on Mexican Bean Beetle (Coleoptera: Coccinellidae), Nontarget Arthropods, and Crop Performance in Southwestern Virginia Snap Beans.

    PubMed

    Nottingham, L; Kuhar, T P; Kring, T; Herbert, D A; Arancibia, R; Schultz, P

    2017-12-08

    Thiamethoxam is a neonicotinoid insecticide commonly applied directly to the seeds (seed-treatment) of commercial snap beans, Phaseolus vulgaris L. While previous studies have examined target and nontarget effects of thiamethoxam seed-treatments in snap beans and other crops, to our knowledge, none have been conducted in agroecosystems predominated by the pest Mexican bean beetle, Epilachna varivestis Mulsant (Coleoptera: Coccinellidae). This study examined the effects of thiamethoxam-treated snap beans on E. varivestis, other arthropods, and crop performance in southwestern Virginia. Greenhouse experiments were conducted to evaluate residual toxicity of treated snap beans to E. varivestis and a key predator, Podisus maculiventris (Say) (Hemiptera: Pentatomidae). Treated plants were highly toxic to E. varivestis at 13 d, moderately toxic from 16 to 20 d, and minimally toxic at 24 d. P. maculiventris was unaffected by exposure to treated plants or by feeding on E. varivestis that consumed treated plants. Small plot field experiments in 2014 and 2015 showed no significant effects of thiamethoxam seed-treatments on E. varivestis densities, other arthropods, crop injury, or yield. In 2016, planting was delayed by persistent rain, resulting in early E. varivestis colonization. In this year, thiamethoxam-treated plants had significantly lower densities and feeding injury from E. varivestis, followed by significantly higher yields. Natural enemies were unaffected by seed-treatments in all field experiments. These experiments demonstrated that thiamethoxam seed-treatments provide control of E. varivestis when beetles infest fields within 2 to 3 wk after planting; but otherwise provide negligible advantages. Negative effects from thiamethoxam seed-treatments on nontarget arthropods appear minimal for snap beans in this region. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please

  6. Flight calibration of compensated and uncompensated pitot-static airspeed probes and application of the probes to supersonic cruise vehicles

    NASA Technical Reports Server (NTRS)

    Webb, L. D.; Washington, H. P.

    1972-01-01

    Static pressure position error calibrations for a compensated and an uncompensated XB-70 nose boom pitot static probe were obtained in flight. The methods (Pacer, acceleration-deceleration, and total temperature) used to obtain the position errors over a Mach number range from 0.5 to 3.0 and an altitude range from 25,000 feet to 70,000 feet are discussed. The error calibrations are compared with the position error determined from wind tunnel tests, theoretical analysis, and a standard NACA pitot static probe. Factors which influence position errors, such as angle of attack, Reynolds number, probe tip geometry, static orifice location, and probe shape, are discussed. Also included are examples showing how the uncertainties caused by position errors can affect the inlet controls and vertical altitude separation of a supersonic transport.

  7. Numerical study of the effects of contact angle and viscosity ratio on the dynamics of snap-off through porous media

    NASA Astrophysics Data System (ADS)

    Starnoni, Michele; Pokrajac, Dubravka

    2018-01-01

    Snap-off is a pore-scale mechanism occurring in porous media in which a bubble of non-wetting phase displacing a wetting phase, and vice-versa, can break-up into ganglia when passing through a constriction. This mechanism is very important in foam generation processes, enhanced oil recovery techniques and capillary trapping of CO2 during its geological storage. In the present study, the effects of contact angle and viscosity ratio on the dynamics of snap-off are examined by simulating drainage in a single pore-throat constriction of variable cross-section, and for different pore-throat geometries. To model the flow, we developed a CFD code based on the Finite Volume method. The Volume-of-fluid method is used to track the interfaces. Results show that the threshold contact angle for snap-off, i.e. snap-off occurs only for contact angles smaller than the threshold, increases from a value of 28° for a circular cross-section to 30-34° for a square cross-section and up to 40° for a triangular one. For a throat of square cross-section, increasing the viscosity of the injected phase results in a drop in the threshold contact angle from a value of 30° when the viscosity ratio μ bar is equal to 1 to 26° when μ bar = 20 and down to 24° when μ bar = 20 .

  8. Shock-wave proton acceleration from a hydrogen gas jet

    NASA Astrophysics Data System (ADS)

    Cook, Nathan; Pogorelsky, Igor; Polyanskiy, Mikhail; Babzien, Marcus; Tresca, Olivier; Maharjan, Chakra; Shkolnikov, Peter; Yakimenko, Vitaly

    2013-04-01

    Typical laser acceleration experiments probe the interaction of intense linearly-polarized solid state laser pulses with dense metal targets. This interaction generates strong electric fields via Transverse Normal Sheath Acceleration and can accelerate protons to high peak energies but with a large thermal spectrum. Recently, the advancement of high pressure amplified CO2 laser technology has allowed for the creation of intense (10^16 Wcm^2) pulses at λ˜10 μm. These pulses may interact with reproducible, high rep. rate gas jet targets and still produce plasmas of critical density (nc˜10^19 cm-3), leading to the transference of laser energy via radiation pressure. This acceleration mode has the advantage of producing narrow energy spectra while scaling well with pulse intensity. We observe the interaction of an intense CO2 laser pulse with an overdense hydrogen gas jet. Using two pulse optical probing in conjunction with interferometry, we are able to obtain density profiles of the plasma. Proton energy spectra are obtained using a magnetic spectrometer and scintillating screen.

  9. An efficacy trial of brief lifestyle intervention delivered by generalist community nurses (CN SNAP trial).

    PubMed

    Laws, Rachel A; Chan, Bibiana C; Williams, Anna M; Davies, Gawaine Powell; Jayasinghe, Upali W; Fanaian, Mahnaz; Harris, Mark F

    2010-02-23

    Lifestyle risk factors, in particular smoking, nutrition, alcohol consumption and physical inactivity (SNAP) are the main behavioural risk factors for chronic disease. Primary health care (PHC) has been shown to be an effective setting to address lifestyle risk factors at the individual level. However much of the focus of research to date has been in general practice. Relatively little attention has been paid to the role of nurses working in the PHC setting. Community health nurses are well placed to provide lifestyle intervention as they often see clients in their own homes over an extended period of time, providing the opportunity to offer intervention and enhance motivation through repeated contacts. The overall aim of this study is to evaluate the impact of a brief lifestyle intervention delivered by community nurses in routine practice on changes in clients' SNAP risk factors. The trial uses a quasi-experimental design involving four generalist community nursing services in NSW Australia. Services have been randomly allocated to an 'early intervention' group or 'late intervention' (comparison) group. 'Early intervention' sites are provided with training and support for nurses in identifying and offering brief lifestyle intervention for clients during routine consultations. 'Late intervention site' provide usual care and will be offered the study intervention following the final data collection point. A total of 720 generalist community nursing clients will be recruited at the time of referral from participating sites. Data collection consists of 1) telephone surveys with clients at baseline, three months and six months to examine change in SNAP risk factors and readiness to change 2) nurse survey at baseline, six and 12 months to examine changes in nurse confidence, attitudes and practices in the assessment and management of SNAP risk factors 3) semi-structured interviews/focus with nurses, managers and clients in 'early intervention' sites to explore the

  10. Non-isothermal elastoviscoplastic snap-through and creep buckling of shallow arches

    NASA Technical Reports Server (NTRS)

    Simitses, G. J.; Riff, R.

    1987-01-01

    The problem of buckling of shallow arches under transient thermomechanical loads is investigated. The analysis is based on nonlinear geometric and constitutive relations, and is expressed in a rate form. The material constitutive equations are capable of reproducing all non-isothermal, elasto-viscoplastic characteristics. The solution scheme is capable of predicting response which includes pre and postbuckling with creep and plastic effects. The solution procedure is demonstrated through several examples which include both creep and snap-through behavior.

  11. Weak lensing probe of cubic Galileon model

    NASA Astrophysics Data System (ADS)

    Dinda, Bikash R.

    2018-06-01

    The cubic Galileon model containing the lowest non-trivial order action of the full Galileon action can produce the stable late-time cosmic acceleration. This model can have a significant role in the growth of structures. The signatures of the cubic Galileon model in the structure formation can be probed by the weak lensing statistics. Weak lensing convergence statistics is one of the strongest probes to the structure formation and hence it can probe the dark energy or modified theories of gravity models. In this work, we investigate the detectability of the cubic Galileon model from the ΛCDM model or from the canonical quintessence model through the convergence power spectrum and bi-spectrum.

  12. Thomson-backscattered x rays from laser-accelerated electrons.

    PubMed

    Schwoerer, H; Liesfeld, B; Schlenvoigt, H-P; Amthor, K-U; Sauerbrey, R

    2006-01-13

    We present the first observation of Thomson-backscattered light from laser-accelerated electrons. In a compact, all-optical setup, the "photon collider," a high-intensity laser pulse is focused into a pulsed He gas jet and accelerates electrons to relativistic energies. A counterpropagating laser probe pulse is scattered from these high-energy electrons, and the backscattered x-ray photons are spectrally analyzed. This experiment demonstrates a novel source of directed ultrashort x-ray pulses and additionally allows for time-resolved spectroscopy of the laser acceleration of electrons.

  13. Experimental heat transfer distribution on the SNAP 10A reactor

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

    Hopenfeld, J.; Toews, R.E.

    1965-01-29

    Heating distributions have been obtained for the SNAP 10A reactor by means of a thermal paint technique in the Rhodes and Bloxsom 60 in. hypersonic wind tunnel. Data and correlations are presented only for those reactor components where the ratio of the local heat transfer to that on the stagnation point of the calibration sphere was found to be independent of tunnel conditions. It is shown that these heating distributions can be applied directly to reentry conditions provided the thermally painted and the bare reactor surfaces are both catalytic to atom recombination.

  14. LCRE and SNAP 50-DR-1 programs. Engineering progress report, October 1, 1962--December 31, 1962

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

    None

    Declassified 5 Sep 1973. Information is presented concerning LCRE specifications, reactor kinetics, fuel elements, primary coolant circuit, secondary coolant circuit, materials development, and fabrication; and SNAP50-DR- 1 specifications, primary pump, and materials development. (DCC)

  15. Exploring the association of urban or rural county status and environmental, nutrition- and lifestyle-related resources with the efficacy of SNAP-Ed (Supplemental Nutrition Assistance Program-Education) to improve food security.

    PubMed

    Rivera, Rebecca L; Dunne, Jennifer; Maulding, Melissa K; Wang, Qi; Savaiano, Dennis A; Nickols-Richardson, Sharon M; Eicher-Miller, Heather A

    2018-04-01

    To investigate the association of policy, systems and environmental factors with improvement in household food security among low-income Indiana households with children after a Supplemental Nutrition Assistance Program-Education (SNAP-Ed) direct nutrition education intervention. Household food security scores measured by the eighteen-item US Household Food Security Survey Module in a longitudinal randomized and controlled SNAP-Ed intervention study conducted from August 2013 to April 2015 were the response variable. Metrics to quantify environmental factors including classification of urban or rural county status; the number of SNAP-authorized stores, food pantries and recreational facilities; average fair market housing rental price; and natural amenity rank were collected from government websites and data sets covering the years 2012-2016 and used as covariates in mixed multiple linear regression modelling. Thirty-seven Indiana counties, USA, 2012-2016. SNAP-Ed eligible adults from households with children (n 328). None of the environmental factors investigated were significantly associated with changes in household food security in this exploratory study. SNAP-Ed improves food security regardless of urban or rural location or the environmental factors investigated. Expansion of SNAP-Ed in rural areas may support food access among the low-income population and reduce the prevalence of food insecurity in rural compared with urban areas. Further investigation into policy, systems and environmental factors of the Social Ecological Model are warranted to better understand their relationship with direct SNAP-Ed and their impact on diet-related behaviours and food security.

  16. Study of Crystal Formation and Nitric Oxide (NO) Release Mechanism from S-Nitroso-N-acetylpenicillamine (SNAP)-Doped CarboSil Polymer Composites for Potential Antimicrobial Applications.

    PubMed

    Wo, Yaqi; Li, Zi; Colletta, Alessandro; Wu, Jianfeng; Xi, Chuanwu; Matzger, Adam J; Brisbois, Elizabeth J; Bartlett, Robert H; Meyerhoff, Mark E

    2017-07-15

    Stable and long-term nitric oxide (NO) releasing polymeric materials have many potential biomedical applications. Herein, we report the real-time observation of the crystallization process of the NO donor, S -nitroso- N -acetylpenicillamine (SNAP), within a thermoplastic silicone-polycarbonate-urethane biomedical polymer, CarboSil 20 80A. It is demonstrated that the NO release rate from this composite material is directly correlated with the surface area that the CarboSil polymer film is exposed to when in contact with aqueous solution. The decomposition of SNAP in solution (e.g. PBS, ethanol, THF, etc.) is a pseudo-first-order reaction proportional to the SNAP concentration. Further, catheters fabricated with this novel NO releasing composite material are shown to exhibit significant effects on preventing biofilm formation on catheter surface by Pseudomonas aeruginosa and Proteus mirabilis grown in CDC bioreactor over 14 days, with a 2 and 3 log-unit reduction in number of live bacteria on their surfaces, respectively. Therefore, the SNAP-CarboSil composite is a promising new material to develop antimicrobial catheters, as well as other biomedical devices.

  17. LCRE and SNAP 50-DR-1 programs. Engineering progress report, January 1, 1963--March 31, 1963

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

    None

    Declassified 5 Sep 1973. Information is presented concerning LCRE specifications, primary coolant circuit, aaxiliary systems, fuel elements, instrumentation, materials development, and fabrication; and SNAP-50DR-1 specifications, fuel elements, pumps, steam generator, and materials development. (DCC)

  18. SNAP: Automated Generation of High-Accuracy Interatomic Potentials using Quantum Data

    NASA Astrophysics Data System (ADS)

    Thompson, Aidan; Wood, Mitchell; Phillpot, Simon

    Molecular dynamics simulation is a powerful computational method for bridging between macroscopic continuum models and quantum models treating a few hundred atoms, but it is limited by the accuracy of the interatomic potential. Sound physical and chemical understanding have led to good potentials for certain systems, but it is difficult to extend them to new materials and properties. The solution is obvious but challenging: develop more complex potentials that reproduce large quantum datasets. The growing availability of large data sets has made it possible to use automated machine-learning approaches for interatomic potential development. In the SNAP approach, the interatomic potential depends on a very general set of atomic neighborhood descriptors, based on the bispectrum components of the density projected onto the surface of the unit 3-sphere. Previously, this approach was demonstrated for tantalum, reproducing the screw dislocation Peierls barrier. In this talk, it will be shown that the SNAP method is capable of reproducing a wide range of energy landscapes relevant to diverse material science applications: i) point defects in indium phosphide, ii) stability of tungsten surfaces at high temperatures, and iii) formation of intrinsic defects in uranium. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corp., for the U.S. Dept. of Energys National Nuclear Security Admin. under contract DE-AC04-94AL85000.

  19. Surgical Treatment of Snapping Scapula Syndrome Due to Malunion of Rib Fractures.

    PubMed

    Ten Duis, Kaj; IJpma, Frank F A

    2017-02-01

    This report describes a case of snapping scapula syndrome (SSS) caused by malunited rib fractures. Abrasion of the deformed ribs was performed with good results. SSS as a cause of shoulder pain after thoracic trauma has to be considered and can be treated by a surgical abrasion technique. Copyright © 2017 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

  20. Subacute casemix classification for stroke rehabilitation in Australia. How well does AN-SNAP v2 explain variance in outcomes?

    PubMed

    Kohler, Friedbert; Renton, Roger; Dickson, Hugh G; Estell, John; Connolly, Carol E

    2011-02-01

    We sought the best predictors for length of stay, discharge destination and functional improvement for inpatients undergoing rehabilitation following a stroke and compared these predictors against AN-SNAP v2. The Oxfordshire classification subgroup, sociodemographic data and functional data were collected for patients admitted between 1997 and 2007, with a diagnosis of recent stroke. The data were factor analysed using Principal Components Analysis for categorical data (CATPCA). Categorical regression analyses was performed to determine the best predictors of length of stay, discharge destination, and functional improvement. A total of 1154 patients were included in the study. Principal components analysis indicated that the data were effectively unidimensional, with length of stay being the most important component. Regression analysis demonstrated that the best predictor was the admission motor FIM score, explaining 38.9% of variance for length of stay, 37.4%.of variance for functional improvement and 16% of variance for discharge destination. The best explanatory variable in our inpatient rehabilitation service is the admission motor FIM. AN- SNAP v2 classification is a less effective explanatory variable. This needs to be taken into account when using AN-SNAP v2 classification for clinical or funding purposes.

  1. Secretory proteins in the reproductive tract of the snapping turtle, Chelhydra serpentina.

    PubMed

    Mahmoud, I Y; Paulson, J R; Dudley, M; Patzlaff, J S; Al-Kindi, A Y A

    2004-12-01

    SDS-polyacrylamide gel electrophoresis was used to separate the secretory proteins produced by the epithelial and endometrial glands of the uterine tube and uterus in the snapping turtle Chelydra serpentina. The proteins were analyzed throughout the phases of the reproductive cycle from May to August, including preovulatory, ovulatory, postovulatory or luteal, and vitellogenic phases. The pattern of secretory proteins is quite uniform along the length of the uterine tube, and the same is true of the uterus, but the patterns for uterine tube and uterus are clearly different. We identify 13 major proteins in C. serpentina egg albumen. Bands co-migrating with 11 of these are found in the uterine tube, but at most 4 are found in the uterus, suggesting that the majority of the albumen proteins are most likely secreted in the uterine tube, not in the uterus. Although some of the egg albumen proteins are present in the uterine tube only at the time of ovulation, most of the bands corresponding to albumen proteins are present throughout the breeding season even though the snapping turtle is a monoclutch species. These results suggest that the glandular secretory phase in the uterine tube is active and quite homogeneous in function regardless of location or phase of the reproductive cycle.

  2. Reproductive skew drives patterns of sexual dimorphism in sponge-dwelling snapping shrimps

    PubMed Central

    Chak, Solomon Tin Chi; Duffy, J. Emmett; Rubenstein, Dustin R.

    2015-01-01

    Sexual dimorphism is typically a result of strong sexual selection on male traits used in male–male competition and subsequent female choice. However, in social species where reproduction is monopolized by one or a few individuals in a group, selection on secondary sexual characteristics may be strong in both sexes. Indeed, sexual dimorphism is reduced in many cooperatively breeding vertebrates and eusocial insects with totipotent workers, presumably because of increased selection on female traits. Here, we examined the relationship between sexual dimorphism and sociality in eight species of Synalpheus snapping shrimps that vary in social structure and degree of reproductive skew. In species where reproduction was shared more equitably, most members of both sexes were physiologically capable of breeding. However, in species where reproduction was monopolized by a single individual, a large proportion of females—but not males—were reproductively inactive, suggesting stronger reproductive suppression and conflict among females. Moreover, as skew increased across species, proportional size of the major chela—the primary antagonistic weapon in snapping shrimps—increased among females and sexual dimorphism in major chela size declined. Thus, as reproductive skew increases among Synalpheus, female–female competition over reproduction appears to increase, resulting in decreased sexual dimorphism in weapon size. PMID:26041357

  3. Neighbourhood and consumer food environment is associated with dietary intake among Supplemental Nutrition Assistance Program (SNAP) participants in Fayette County, Kentucky.

    PubMed

    Gustafson, Alison; Lewis, Sarah; Perkins, Sarah; Wilson, Corey; Buckner, Elizabeth; Vail, Ann

    2013-07-01

    The aim of the study was to determine the association between dietary outcomes and the neighbourhood food environment (street network distance from home to stores) and consumer food environment (Nutrition Environment Measurement Survey-Stores (NEMS-S) audit). The neighbourhood food environment was captured by creating 0?5-mile and 1-mile network distance (street distance) around each participant’s home and the nearest food venue (convenience store, grocery store, supermarket, farmers’ market and produce stand). The consumer food environment was captured by conducting NEMS-S in all grocery stores/supermarkets within 0?5 and 1 mile of participants’ homes. Fayette County, KY, USA. Supplemental Nutrition Assessment Program (SNAP) participants, n 147. SNAP participants who lived within 0?5 mile of at least one farmers’ market/produce stand had higher odds of consuming one serving or more of vegetables (OR56?92; 95% CI 4?09, 11?69), five servings or more of grains (OR51?76; 95% CI 1?01, 3?05) and one serving or more of milk (OR53?79; 95% CI 2?14, 6?71) on a daily basis. SNAP participants who lived within 0?5 mile of stores receiving a high score on the NEMS-S audit reported higher odds of consuming at least one serving of vegetables daily (OR53?07; 95% CI 1?78, 5?31). Taken together, both the neighbourhood food environment and the consumer food environment are associated with a healthy dietary intake among SNAP participants.

  4. Probing SEP Acceleration Processes With Near-relativistic Electrons

    NASA Astrophysics Data System (ADS)

    Haggerty, Dennis K.; Roelof, Edmond C.

    2009-11-01

    Processes in the solar corona are prodigious accelerators of near-relativistic electrons. Only a small fraction of these electrons escape the low corona, yet they are by far the most abundant species observed in Solar Energetic Particle events. These beam-like energetic electron events are sometimes time-associated with coronal mass ejections from the western solar hemisphere. However, a significant number of events are observed without any apparent association with a transient event. The relationship between solar energetic particle events, coronal mass ejections, and near-relativistic electron events are better ordered when we classify the intensity time profiles during the duration of the beam-like anisotropies into three broad categories: 1) Spikes (rapid and equal rise and decay) 2) Pulses (rapid rise, slower decay) and 3) Ramps (rapid rise followed by a plateau). We report on the results of a study that is based on our catalog (covering nearly the complete Solar Cycle 23) of 216 near-relativistic electron events and their association with: solar electromagnetic emissions, shocks driven by coronal mass ejections, models of the coronal magnetic fields and energetic protons. We conclude that electron events with time-intensity profiles of Spikes and Pulses are associated with explosive events in the low corona while events with time-intensity profiles of Ramps are associated with the injection/acceleration process of the CME driven shock.

  5. Dark energy two decades after: observables, probes, consistency tests.

    PubMed

    Huterer, Dragan; Shafer, Daniel L

    2018-01-01

    The discovery of the accelerating universe in the late 1990s was a watershed moment in modern cosmology, as it indicated the presence of a fundamentally new, dominant contribution to the energy budget of the universe. Evidence for dark energy, the new component that causes the acceleration, has since become extremely strong, owing to an impressive variety of increasingly precise measurements of the expansion history and the growth of structure in the universe. Still, one of the central challenges of modern cosmology is to shed light on the physical mechanism behind the accelerating universe. In this review, we briefly summarize the developments that led to the discovery of dark energy. Next, we discuss the parametric descriptions of dark energy and the cosmological tests that allow us to better understand its nature. We then review the cosmological probes of dark energy. For each probe, we briefly discuss the physics behind it and its prospects for measuring dark energy properties. We end with a summary of the current status of dark energy research.

  6. Parker Solar Probe: A NASA Mission to Touch the Sun: Mission Status Update

    NASA Astrophysics Data System (ADS)

    Fox, N. J.

    2017-12-01

    The newly renamed, Parker Solar Probe (PSP) mission will be the first mission to fly into the low solar corona, revealing how the corona is heated and the solar wind and energetic particles are accelerated, solving fundamental mysteries that have been top priority science goals since such a mission was first proposed in 1958. The scale and concept of such a mission has been revised at intervals since that time, yet the core has always been a close encounter with the Sun. The primary science goal of the Parker Solar Probe mission is to determine the structure and dynamics of the Sun's coronal magnetic field, understand how the solar corona and wind are heated and accelerated, and determine what mechanisms accelerate and transport energetic particles. PSP uses an innovative mission design, significant technology development and a risk-reducing engineering development to meet the science objectives. In this presentation, we provide an update on the progress of the Parker Solar Probe mission as we prepare for the July 2018 launch.

  7. Solar Probe Plus: A NASA Mission to Touch the SunMission Status Update

    NASA Astrophysics Data System (ADS)

    Fox, N. J.

    2016-12-01

    Solar Probe Plus (SPP), currently in Phase D, will be the first mission to fly into the low solar corona, revealing how the corona is heated and the solar wind and energetic particles are accelerated, solving fundamental mysteries that have been top priority science goals since such a mission was first proposed in 1958. The scale and concept of such a mission has been revised at intervals since that time, yet the core has always been a close encounter with the Sun. The primary science goal of the Solar Probe Plus mission is to determine the structure and dynamics of the Sun's coronal magnetic field, understand how the solar corona and wind are heated and accelerated, and determine what mechanisms accelerate and transport energetic particles. SPP uses an innovative mission design, significant technology development and a risk-reducing engineering development to meet the SPP science objectives. In this presentation, we provide an update on the progress of the Solar Probe Plus mission as we prepare for the July 2018 launch.

  8. GAMMA-RAY AND HARD X-RAY EMISSION FROM PULSAR-AIDED SUPERNOVAE AS A PROBE OF PARTICLE ACCELERATION IN EMBRYONIC PULSAR WIND NEBULAE

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

    Murase, Kohta; Kashiyama, Kazumi; Kiuchi, Kenta

    2015-05-20

    It has been suggested that some classes of luminous supernovae (SNe) and gamma-ray bursts (GRBs) are driven by newborn magnetars. Fast-rotating proto-neutron stars have also been of interest as potential sources of gravitational waves (GWs). We show that for a range of rotation periods and magnetic fields, hard X-rays and GeV gamma rays provide us with a promising probe of pulsar-aided SNe. It is observationally known that young pulsar wind nebulae (PWNe) in the Milky Way are very efficient lepton accelerators. We argue that, if embryonic PWNe satisfy similar conditions at early stages of SNe (in ∼1–10 months after themore » explosion), external inverse-Compton emission via upscatterings of SN photons is naturally expected in the GeV range as well as broadband synchrotron emission. To fully take into account the Klein–Nishina effect and two-photon annihilation process that are important at early times, we perform detailed calculations including electromagnetic cascades. Our results suggest that hard X-ray telescopes such as NuSTAR can observe such early PWN emission by follow-up observations in months to years. GeV gamma-rays may also be detected by Fermi for nearby SNe, which serve as counterparts of these GW sources. Detecting the signals will give us an interesting probe of particle acceleration at early times of PWNe, as well as clues to driving mechanisms of luminous SNe and GRBs. Since the Bethe–Heitler cross section is lower than the Thomson cross section, gamma rays would allow us to study subphotospheric dissipation. We encourage searches for high-energy emission from nearby SNe, especially SNe Ibc including super-luminous objects.« less

  9. Elastoviscoplastic snap-through behavior of shallow arches subjected to thermomechanical loads

    NASA Technical Reports Server (NTRS)

    Simitses, George J.; Song, Yuzhao; Sheinman, Izhak

    1991-01-01

    The problem of snap-through buckling of clamped shallow arches under thermomechanical loads is investigated. The analysis is based on nonlinear kinematic relations and nonlinear rate-dependent unified constitutive equations. A finite element approach is employed to predict the, in general, inelastic buckling behavior. The construction material is alloy B1900 + Hf, which is commonly utilized in high-temperature environments. The effect of several parameters is assessed. These parameters include the rise parameter and temperature. Comparison between elastic and elastoviscoplastic responses is also presented.

  10. Improved hemocompatibility of silicone rubber extracorporeal tubing via solvent swelling-impregnation of S-nitroso-N-acetylpenicillamine (SNAP) and evaluation in rabbit thrombogenicity model.

    PubMed

    Brisbois, Elizabeth J; Major, Terry C; Goudie, Marcus J; Bartlett, Robert H; Meyerhoff, Mark E; Handa, Hitesh

    2016-06-01

    Blood-contacting devices, including extracorporeal circulation (ECC) circuits, can suffer from complications due to platelet activation and thrombus formation. Development of nitric oxide (NO) releasing polymers is one method to improve hemocompatibility, taking advantage of the ability of low levels of NO to prevent platelet activation/adhesion. In this study a novel solvent swelling method is used to load the walls of silicone rubber tubing with the NO donor S-nitroso-N-acetylpenicillamine (SNAP). This SNAP-silicone rubber tubing exhibits an NO flux of ca. 1×10(-10)molcm(-2)min(-1), which mimics the range of NO release from the normal endothelium, which is stable for at least 4h. Images of the tubing before and after swelling, obtained via scanning electron microscopy, demonstrate that this swelling method has little effect on the surface properties of the tubing. The SNAP-loaded silicone rubber and silicone rubber control tubing are used to fabricate ECC circuits that are evaluated in a rabbit model of thrombogenicity. After 4h of blood flow, the SNAP-loaded silicone rubber circuits were able to preserve the blood platelet count at 64% of baseline (vs. 12% for silicone rubber control). A 67% reduction in the degree of thrombus formation within the thrombogenicity chamber was also observed. This study demonstrates the ability to improve the hemocompatibility of existing/commercial silicone rubber tubing via a simple solvent swelling-impregnation technique, which may also be applicable to other silicone-based blood-contacting devices. Localized nitric oxide (NO) release can be achieved from biomedical grade polymers doped with S-nitroso-N-acetylpenicillamine (SNAP). Despite the promising in vitro and in vivo biocompatibility results reported for these NO releasing polymers, many of these materials may face challenges in being translated to clinical applications, especially in the areas of polymer processing and manufacturing. In this study, we report a solvent

  11. PERFORMANCE TESTS OF SNAP 10A THERMOELECTRIC ELEMENTS

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

    Bergdorf, C.G.

    1961-08-30

    Apparatus for the performanee testing of SNAP 10A thermoelectric elements was designed, constructed, and is now in operation. Elements may be tested for any desired length of tfme up to 1400 deg F and in a vacuum of 1 x 10/ sup -5/ of Hg. The equipment used for these tcsts may also be utilized for measuring Seebeck coefficient and resistance as a function of temperature. Element performance is derived from the data on voltages and temperatures. The performance variables which are reported in graphic form are as follows: loaded output voltage at any desired DELTA T; open circuit outputmore » voltage at any desired DELTA T; power output under optimum load conditions; current produced under matched load conditions; and internal resistance of the element. (auth)« less

  12. Future HEP Accelerators: The US Perspective

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

    Bhat, Pushpalatha; Shiltsev, Vladimir

    2015-11-02

    Accelerator technology has advanced tremendously since the introduction of accelerators in the 1930s, and particle accelerators have become indispensable instruments in high energy physics (HEP) research to probe Nature at smaller and smaller distances. At present, accelerator facilities can be classified into Energy Frontier colliders that enable direct discoveries and studies of high mass scale particles and Intensity Frontier accelerators for exploration of extremely rare processes, usually at relatively low energies. The near term strategies of the global energy frontier particle physics community are centered on fully exploiting the physics potential of the Large Hadron Collider (LHC) at CERN throughmore » its high-luminosity upgrade (HL-LHC), while the intensity frontier HEP research is focused on studies of neutrinos at the MW-scale beam power accelerator facilities, such as Fermilab Main Injector with the planned PIP-II SRF linac project. A number of next generation accelerator facilities have been proposed and are currently under consideration for the medium- and long-term future programs of accelerator-based HEP research. In this paper, we briefly review the post-LHC energy frontier options, both for lepton and hadron colliders in various regions of the world, as well as possible future intensity frontier accelerator facilities.« less

  13. Micro-Sugar-Snap and -Wire-Cut Cookie Baking with Trans- and Zero-Trans-Fat Shortenings

    USDA-ARS?s Scientific Manuscript database

    The effect of trans- and zero-trans-fat shortenings on cookie-baking performance was evaluated, using the two AACC micro-cookie-baking methods. Regardless of fat type, sugar-snap cookies made with a given flour were larger in diameter, smaller in height, and greater in weight loss during baking tha...

  14. Accelerated Photobleaching of a Cyanine Dye in the Presence of a Ternary Target DNA, PNA Probe, Dye Catalytic Complex: A Molecular Diagnostic

    PubMed Central

    Wang, M.; Holmes-Davis, R.; Rafinski, Z.; Jedrzejewska, B.; Choi, K. Y.; Zwick, M.; Bupp, C.; Izmailov, A.; Paczkowski, J.; Warner, B.; Koshinsky, H.

    2009-01-01

    In many settings, molecular testing is needed but unavailable due to complexity and cost. Simple, rapid, and specific DNA detection technologies would provide important alternatives to existing detection methods. Here we report a novel, rapid nucleic acid detection method based on the accelerated photobleaching of the light-sensitive cyanine dye, 3,3′-diethylthiacarbocyanine iodide (DiSC2(3) I−), in the presence of a target genomic DNA and a complementary peptide nucleic acid (PNA) probe. On the basis of the UV–vis, circular dichroism, and fluorescence spectra of DiSC2(3) with PNA–DNA oligomer duplexes and on characterization of a product of photolysis of DiSC2(3) I−, a possible reaction mechanism is proposed. We propose that (1) a novel complex forms between dye, PNA, and DNA, (2) this complex functions as a photosensitizer producing 1O2, and (3) the 1O2 produced promotes photobleaching of dye molecules in the mixture. Similar cyanine dyes (DiSC3(3), DiSC4(3), DiSC5(3), and DiSCpy(3)) interact with preformed PNA–DNA oligomer duplexes but do not demonstrate an equivalent accelerated photobleaching effect in the presence of PNA and target genomic DNA. The feasibility of developing molecular diagnostic assays based on the accelerated photobleaching (the smartDNA assay) that results from the novel complex formed between DiSC2(3) and PNA–DNA is under way. PMID:19231844

  15. Malignant melanoma with preserved hairs: a snap shot could suggest the development from an acquired melanocytic nevus.

    PubMed

    Kiyohara, Takahiro; Kouraba, Sachio; Takahashi, Hidenori; Kawasaki, Takeo; Takeuchi, Akiteru; Kumakiri, Masanobu

    2010-02-01

    63-year-old man presented with a dome-shaped, black nodule on his right forehead, where hairs were preserved. The black surface tone measured 7 mm in diameter and spread irregularly from the periphery of the nodule. He had been conscious of the preceding, black macule for approximately 50 years. A snap shot of the patient in adolescence showed a tiny, black macule, which was a few millimeters in diameter. Histological examination demonstrated irregular proliferation of melanoma cells from the epidermis to the dermis. Partially, there were well-circumscribed, oval nests composed of nevus cells in the acanthotic epidermis and follicles. Nevus cells were also seen in the dermal component, presenting a burnt-out appearance. In this case, the small final size, the preserved hairs and the snap shot suggested a preceding, acquired melanocytic nevus. Malignant melanoma could arise from acquired melanocytic nevus.

  16. IJS procedure for RELAP5 to TRACE input model conversion using SNAP

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

    Prosek, A.; Berar, O. A.

    2012-07-01

    The TRAC/RELAP Advanced Computational Engine (TRACE) advanced, best-estimate reactor systems code developed by the U.S. Nuclear Regulatory Commission comes with a graphical user interface called Symbolic Nuclear Analysis Package (SNAP). Much of efforts have been done in the past to develop the RELAP5 input decks. The purpose of this study is to demonstrate the Institut 'Josef Stefan' (IJS) conversion procedure from RELAP5 to TRACE input model of BETHSY facility. The IJS conversion procedure consists of eleven steps and is based on the use of SNAP. For calculations of the selected BETHSY 6.2TC test the RELAP5/MOD3.3 Patch 4 and TRACE V5.0more » Patch 1 were used. The selected BETHSY 6.2TC test was 15.24 cm equivalent diameter horizontal cold leg break in the reference pressurized water reactor without high pressure and low pressure safety injection. The application of the IJS procedure for conversion of BETHSY input model showed that it is important to perform the steps in proper sequence. The overall calculated results obtained with TRACE using the converted RELAP5 model were close to experimental data and comparable to RELAP5/MOD3.3 calculations. Therefore it can be concluded, that proposed IJS conversion procedure was successfully demonstrated on the BETHSY integral test facility input model. (authors)« less

  17. EBT Payment for Online Grocery Orders: a Mixed-Methods Study to Understand Its Uptake among SNAP Recipients and the Barriers to and Motivators for Its Use.

    PubMed

    Martinez, Olivia; Tagliaferro, Barbara; Rodriguez, Noemi; Athens, Jessica; Abrams, Courtney; Elbel, Brian

    2018-04-01

    To examine Supplemental Nutrition Assistance Program (SNAP) recipients' use of the first online supermarket accepting Electronic Benefit Transfer (EBT) payment. In this mixed-methods study, the authors collected EBT purchase data from an online grocer and attempted a randomized controlled trial in the South Bronx, New York City, followed by focus groups with SNAP beneficiaries aged ≥18 years. Participants were randomized to shop at their usual grocery store or an online supermarket for 3 months. Focus groups explored barriers and motivators to online EBT redemption. Few participants made online purchases, even when incentivized in the randomized controlled trial. Qualitative findings highlighted a lack of perceived control over the online food selection process as a key barrier to purchasing food online. Motivators included fast, free shipping and discounts. Electronic Benefit Transfer for online grocery purchases has the potential to increase food access among SNAP beneficiaries, but challenges exist to this new food buying option. Understanding online food shopping barriers and motivators is critical to the success of policies targeting the online expansion of SNAP benefits. Copyright © 2017 Society for Nutrition Education and Behavior. Published by Elsevier Inc. All rights reserved.

  18. SNARE proteins synaptobrevin, SNAP-25 and syntaxin are involved in rapid and slow endocytosis at synapses

    PubMed Central

    Xu, Jianhua; Luo, Fujun; Zhang, Zhen; Xue, Lei; Wu, Xinsheng; Chiang, Hsueh-Cheng; Shin, Wonchul; Wu, Ling-Gang

    2013-01-01

    Rapid endocytosis, which takes only a few seconds, is widely observed in secretory cells. Although it is more efficient in recycling vesicles than slow clathrin-mediated endocytosis, its underlying mechanism, thought to be clathrin-independent, is largely unclear. Here we reported that cleavage of three SNARE proteins essential for exocytosis, including synaptobrevin, SNAP-25 and syntaxin, inhibited rapid endocytosis at the calyx of Held nerve terminal, suggesting the involvement of three SNARE proteins in rapid endocytosis. These SNARE proteins were also involved in slow endocytosis. In addition, SNAP-25 and syntaxin facilitated vesicle mobilization to the readily releasable pool, likely via their roles in endocytosis and/or exocytosis. We concluded that both rapid and slow endocytosis share the involvement of SNARE proteins. The dual role of three SNARE proteins in exo- and endocytosis suggests that SNARE proteins may be molecular substrates contributing to the exo-endocytosis coupling, which maintains exocytosis in secretory cells. PMID:23643538

  19. Advanced Accelerators: Particle, Photon and Plasma Wave Interactions

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

    Williams, Ronald L.

    2017-06-29

    The overall objective of this project was to study the acceleration of electrons to very high energies over very short distances based on trapping slowly moving electrons in the fast moving potential wells of large amplitude plasma waves, which have relativistic phase velocities. These relativistic plasma waves, or wakefields, are the basis of table-top accelerators that have been shown to accelerate electrons to the same high energies as kilometer-length linear particle colliders operating using traditional decades-old acceleration techniques. The accelerating electrostatic fields of the relativistic plasma wave accelerators can be as large as GigaVolts/meter, and our goal was to studymore » techniques for remotely measuring these large fields by injecting low energy probe electron beams across the plasma wave and measuring the beam’s deflection. Our method of study was via computer simulations, and these results suggested that the deflection of the probe electron beam was directly proportional to the amplitude of the plasma wave. This is the basis of a proposed diagnostic technique, and numerous studies were performed to determine the effects of changing the electron beam, plasma wave and laser beam parameters. Further simulation studies included copropagating laser beams with the relativistic plasma waves. New interesting results came out of these studies including the prediction that very small scale electron beam bunching occurs, and an anomalous line focusing of the electron beam occurs under certain conditions. These studies were summarized in the dissertation of a graduate student who obtained the Ph.D. in physics. This past research program has motivated ideas for further research to corroborate these results using particle-in-cell simulation tools which will help design a test-of-concept experiment in our laboratory and a scaled up version for testing at a major wakefield accelerator facility.« less

  20. Critical Windows of Cardiovascular Susceptibility to Developmental Hypoxia in Common Snapping Turtle (Chelydra serpentina) Embryos.

    PubMed

    Tate, Kevin B; Kohl, Zachary F; Eme, John; Rhen, Turk; Crossley, Dane A

    2015-01-01

    Environmental conditions fluctuate dramatically in some reptilian nests. However, critical windows of environmental sensitivity for cardiovascular development have not been identified. Continuous developmental hypoxia has been shown to alter cardiovascular form and function in embryonic snapping turtles (Chelydra serpentina), and we used this species to identify critical periods during which hypoxia modifies the cardiovascular phenotype. We hypothesized that incubation in 10% O2 during specific developmental periods would have differential effects on the cardiovascular system versus overall somatic growth. Two critical windows were identified with 10% O2 from 50% to 70% of incubation, resulting in relative heart enlargement, either via preservation of or preferential growth of this tissue, while exposure to 10% O2 from 20% to 70% of incubation resulted in a reduction in arterial pressure. The deleterious or advantageous aspects of these embryonic phenotypes in posthatching snapping turtles have yet to be explored. However, identification of these critical windows has provided insight into how the developmental environment alters the phenotype of reptiles and will also be pivotal in understanding its impact on the fitness of egg-laying reptiles.

  1. Carbon dioxide (CO2) laser treatment of cutaneous papillomas in a common snapping turtle, Chelydra serpentina.

    PubMed

    Raiti, Paul

    2008-06-01

    Carbon dioxide (CO2) laser was used to treat multiple cutaneous papillomas on an adult female common snapping turtle, Chelydra serpentina serpentina. A combination of excisional and ablative techniques provided excellent intraoperative visibility and postoperative results due to the laser's unique ability to incise and vaporize soft tissue.

  2. Which modifiable health risk behaviours are related? A systematic review of the clustering of Smoking, Nutrition, Alcohol and Physical activity ('SNAP') health risk factors.

    PubMed

    Noble, Natasha; Paul, Christine; Turon, Heidi; Oldmeadow, Christopher

    2015-12-01

    There is a growing body of literature examining the clustering of health risk behaviours, but little consensus about which risk factors can be expected to cluster for which sub groups of people. This systematic review aimed to examine the international literature on the clustering of smoking, poor nutrition, excess alcohol and physical inactivity (SNAP) health behaviours among adults, including associated socio-demographic variables. A literature search was conducted in May 2014. Studies examining at least two SNAP risk factors, and using a cluster or factor analysis technique, or comparing observed to expected prevalence of risk factor combinations, were included. Fifty-six relevant studies were identified. A majority of studies (81%) reported a 'healthy' cluster characterised by the absence of any SNAP risk factors. More than half of the studies reported a clustering of alcohol with smoking, and half reported clustering of all four SNAP risk factors. The methodological quality of included studies was generally weak to moderate. Males and those with greater social disadvantage showed riskier patterns of behaviours; younger age was less clearly associated with riskier behaviours. Clustering patterns reported here reinforce the need for health promotion interventions to target multiple behaviours, and for such efforts to be specifically designed and accessible for males and those who are socially disadvantaged. Copyright © 2015 Elsevier Inc. All rights reserved.

  3. LCRE and SNAP 50-DR-1 programs. Engineering and progress report, April 1, 1963--June 30, 1963

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

    None

    BS>Declassified 6 Sep 1973. Information is presented concerning the LCRE kinetics, auxiliary systems, fuel, primary cooling system components, instrumentation, secondary cooling system, materials development, and fabrication; and SNAP-50/SPUR kinetics, fuel, primary system pump, steam generator, and materials development. (DCC)

  4. The analysis of non-linear dynamic behavior (including snap-through) of postbuckled plates by simple analytical solution

    NASA Technical Reports Server (NTRS)

    Ng, C. F.

    1988-01-01

    Static postbuckling and nonlinear dynamic analysis of plates are usually accomplished by multimode analyses, although the methods are complicated and do not give straightforward understanding of the nonlinear behavior. Assuming single-mode transverse displacement, a simple formula is derived for the transverse load displacement relationship of a plate under in-plane compression. The formula is used to derive a simple analytical expression for the static postbuckling displacement and nonlinear dynamic responses of postbuckled plates under sinusoidal or random excitation. Regions with softening and hardening spring behavior are identified. Also, the highly nonlinear motion of snap-through and its effects on the overall dynamic response can be easily interpreted using the single-mode formula. Theoretical results are compared with experimental results obtained using a buckled aluminum panel, using discrete frequency and broadband point excitation. Some important effects of the snap-through motion on the dynamic response of the postbuckled plates are found.

  5. Towards pump-probe experiments of defect dynamics with short ion beam pulses

    NASA Astrophysics Data System (ADS)

    Schenkel, T.; Lidia, S. M.; Weis, C. D.; Waldron, W. L.; Schwartz, J.; Minor, A. M.; Hosemann, P.; Kwan, J. W.

    2013-11-01

    A novel, induction type linear accelerator, the Neutralized Drift Compression eXperiment (NDCX-II), is currently being commissioned at Berkeley Lab. This accelerator is designed to deliver intense (up to 3 × 1011 ions/pulse), 0.6 to ∼600 ns duration pulses of 0.05-1.2 MeV lithium ions at a rate of about 2 pulses per minute onto 1-10 mm scale target areas. When focused to mm-diameter spots, the beam is predicted to volumetrically heat micrometer thick foils to temperatures of ∼30,000 °K. At lower beam power densities, the short excitation pulse with tunable intensity and time profile enables pump-probe type studies of defect dynamics in a broad range of materials. We briefly describe the accelerator concept and design, present results from beam pulse shaping experiments and discuss examples of pump-probe type studies of defect dynamics following irradiation of materials with intense, short ion beam pulses from NDCX-II.

  6. Proton Probing using the T-Cubed Laser

    NASA Astrophysics Data System (ADS)

    Kordell, Peter; Campbell, Paul; Willingale, Louise; Maksimchuk, Anatoly; Krushelnick, Karl; Tubman, Eleanor; Woolsey, Nigel

    2015-11-01

    The University of Michigan's 20 TW, 400 fs pulse T-cubed laser can produce proton beams of up to 7.2 MeV through target normal sheeth acceleration. The proton flux at 4 MeV produces sufficient signal on Radiochromic Film for use as an ultrafast, electromagnetic field diagnostic. A two beam experiment has been set-up to enable co-timed, pump-probe relativistic intensity interactions. We present an evaluation of the flux, uniformity, energy and laminar flow of the proton probe for future use in imaging of a simple wire target interaction. This work was supported by the DOE (Grant No. DE-SC0012327).

  7. Overview of Accelerators with Potential Use in Homeland Security

    NASA Astrophysics Data System (ADS)

    Garnett, Robert W.

    Quite a broad range of accelerators have been applied to solving many of the challenging problems related to homeland security and defense. These accelerator systems range from relatively small, simple, and compact, to large and complex, based on the specific application requirements. They have been used or proposed as sources of primary and secondary probe beams for applications such as radiography and to induce specific reactions that are key signatures for detecting conventional explosives or fissile material. A brief overview and description of these accelerator systems, their specifications, and application will be presented. Some recent technology trends will also be discussed.

  8. Experiments with probe masses

    PubMed Central

    Braginsky, V. B.

    2007-01-01

    It is reasonable to regard the experiments performed by C. Coulomb and H. Cavendish in the end of the 18th century as the beginning of laboratory experimental physics. These outstanding scientists have measured forces (accelerations) produced by electric charges and by gravitational “charges” on probe masses that were attached to torque balance. Among the variety of different research programs and projects existing today, experiments with probe masses are still playing an important role. In this short review, the achieved and planned sensitivities of very challenging LIGO (Laser Interferometer Gravitational wave Observatory) and LISA (Laser Interferometer Space Antennae) projects are described, and a list of nonsolved problems is discussed as well. The role of quantum fluctuations in high precision measurements is also outlined. Apart from these main topics, the limitations of sensitivity caused by cosmic rays and the prospects of clock frequency stability are presented. PMID:17296944

  9. Laser-driven atomic-probe-beam diagnostics

    NASA Astrophysics Data System (ADS)

    Knyazev, B. A.; Greenly, J. B.; Hammer, D. A.

    2000-12-01

    A new laser-driven atomic-probe-beam diagnostic (LAD) is proposed for local, time-resolved measurements of electric field and ion dynamics in the accelerating gap of intense ion beam diodes. LAD adds new features to previous Stark-shift diagnostics which have been progressively developed in several laboratories, from passive observation of Stark effect on ion species or fast (charge-exchanged) neutrals present naturally in diodes, to active Stark atomic spectroscopy (ASAS) in which selected probe atoms were injected into the gap and excited to suitable states by resonant laser radiation. The LAD scheme is a further enhancement of ASAS in which the probe atoms are also used as a local (laser-ionized) ion source at an instant of time. Analysis of the ion energy and angular distribution after leaving the gap enables measurement, at the chosen ionization location in the gap, of both electrostatic potential and the development of ion divergence. Calculations show that all of these quantities can be measured with sub-mm and ns resolution. Using lithium or sodium probe atoms, fields from 0.1 to 10 MV/cm can be measured.

  10. Overweight and Obesity, Weight Perception, and Weight Management Practices Among Supplemental Nutrition Assistance Program-Education (SNAP-Ed) Participants in Georgia: A Needs Assessment.

    PubMed

    Bailey, Claudette; Lee, Jung Sun

    2017-05-01

    Examine associations among weight status, weight perception, and weight management practices of Supplemental Nutrition Assistance Program-Education (SNAP-Ed) participants in Georgia. Self-reported weight, height, and weight-related practices were assessed and analyzed in 270 SNAP-Ed participants. Almost three quarters of the sample self-reported overweight or obesity. Among overweight and obese subjects, 39% and 69%, respectively, accurately perceived themselves as overweight. More than half of the sample desired weight loss and 44% had attempted weight loss in the past year. Overweight/obese subjects who accurately perceived their weight were more likely to desire and to have attempted weight loss than those who under-perceived their weight. Approximately 58% of all subjects who had attempted to lose weight reported use of both methods suggested for weight loss: exercise and dietary changes. The high prevalence of self-reported overweight/obesity combined with a desire to lose weight among the study sample demonstrated the necessity to develop SNAP-Ed curricula emphasizing weight management. Copyright © 2017 Society for Nutrition Education and Behavior. Published by Elsevier Inc. All rights reserved.

  11. Reproductive physiology in eastern snapping turtles (Chelydra serpentina) exposed to runoff from a concentrated animal feeding operation

    EPA Science Inventory

    The eastern snapping turtle (Chelydra serpentina) is widely distributed throughout the eastern and central U.S. and may be a useful model organism to study land use impacts on water quality. We compared the reproductive condition of C. serpentina from a pond impacted by runoff fr...

  12. User’s guide to SNAP for ArcGIS® :ArcGIS interface for scheduling and network analysis program

    Treesearch

    Woodam Chung; Dennis Dykstra; Fred Bower; Stephen O’Brien; Richard Abt; John. and Sessions

    2012-01-01

    This document introduces a computer software named SNAP for ArcGIS® , which has been developed to streamline scheduling and transportation planning for timber harvest areas. Using modern optimization techniques, it can be used to spatially schedule timber harvest with consideration of harvesting costs, multiple products, alternative...

  13. Snapping knee caused by the thickening of the medial hamstrings.

    PubMed

    de la Hera Cremades, B; Escribano Rueda, L; Lara Rubio, A

    We report a case of symptomatic subluxation of the semitendinosus and gracilis over the medial condyle of the tibia caused by the thickening of its tendons. Snapping was reproduced on active extension. Clinical examination and, above all, dynamic ultrasound were the key for the diagnosis because other imaging tests were normal. Due to failure of conservative treatment with physiotherapy and infiltrations, surgery was undertaken, involving desinsertion and excision of distal 8cm segment of the semitendinosus and gracilis tendons. At the present time (6 months postoperatively), the patient is symptom-free and has returned to the previous normal life activities. Copyright © 2016 SECOT. Publicado por Elsevier España, S.L.U. All rights reserved.

  14. Commissioning the GTA accelerator

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

    Sander, O.R.; Atkins, W.H.; Bolme, G.O.

    1992-09-01

    The Ground Test Accelerator (GTA) is supported by the Strategic Defense command as part of their Neutral Particle Beam (NPB) program. Neutral particles have the advantage that in space they are unaffected by the earth`s magnetic field and travel in straight lines unless they enter the earth`s atmosphere and become charged by stripping. Heavy particles are difficult to stop and can probe the interior of space vehicles; hence, NPB can function as a discriminator between warheads and decoys. We are using GTA to resolve the physics and engineering issues related to accelerating, focusing, and steering a high-brightness, high-current H{sup -}more » beam and then neutralizing it. Our immediate goal is to produce a 24-MeV, 50mA device with a 2% duty factor.« less

  15. Commissioning the GTA accelerator

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

    Sander, O.R.; Atkins, W.H.; Bolme, G.O.

    1992-01-01

    The Ground Test Accelerator (GTA) is supported by the Strategic Defense command as part of their Neutral Particle Beam (NPB) program. Neutral particles have the advantage that in space they are unaffected by the earth's magnetic field and travel in straight lines unless they enter the earth's atmosphere and become charged by stripping. Heavy particles are difficult to stop and can probe the interior of space vehicles; hence, NPB can function as a discriminator between warheads and decoys. We are using GTA to resolve the physics and engineering issues related to accelerating, focusing, and steering a high-brightness, high-current H{sup -}more » beam and then neutralizing it. Our immediate goal is to produce a 24-MeV, 50mA device with a 2% duty factor.« less

  16. Accelerated intoxication of GABAergic synapses by botulinum neurotoxin A disinhibits stem cell-derived neuron networks prior to network silencing

    PubMed Central

    Beske, Phillip H.; Scheeler, Stephen M.; Adler, Michael; McNutt, Patrick M.

    2015-01-01

    Botulinum neurotoxins (BoNTs) are extremely potent toxins that specifically cleave SNARE proteins in peripheral synapses, preventing neurotransmitter release. Neuronal responses to BoNT intoxication are traditionally studied by quantifying SNARE protein cleavage in vitro or monitoring physiological paralysis in vivo. Consequently, the dynamic effects of intoxication on synaptic behaviors are not well-understood. We have reported that mouse embryonic stem cell-derived neurons (ESNs) are highly sensitive to BoNT based on molecular readouts of intoxication. Here we study the time-dependent changes in synapse- and network-level behaviors following addition of BoNT/A to spontaneously active networks of glutamatergic and GABAergic ESNs. Whole-cell patch-clamp recordings indicated that BoNT/A rapidly blocked synaptic neurotransmission, confirming that ESNs replicate the functional pathophysiology responsible for clinical botulism. Quantitation of spontaneous neurotransmission in pharmacologically isolated synapses revealed accelerated silencing of GABAergic synapses compared to glutamatergic synapses, which was consistent with the selective accumulation of cleaved SNAP-25 at GAD1+ pre-synaptic terminals at early timepoints. Different latencies of intoxication resulted in complex network responses to BoNT/A addition, involving rapid disinhibition of stochastic firing followed by network silencing. Synaptic activity was found to be highly sensitive to SNAP-25 cleavage, reflecting the functional consequences of the localized cleavage of the small subpopulation of SNAP-25 that is engaged in neurotransmitter release in the nerve terminal. Collectively these findings illustrate that use of synaptic function assays in networked neurons cultures offers a novel and highly sensitive approach for mechanistic studies of toxin:neuron interactions and synaptic responses to BoNT. PMID:25954159

  17. Snap-lock bags with red band: A study of manufacturing characteristics, thermal and chemical properties.

    PubMed

    Sim, Yvonne Hui Ying; Koh, Alaric C W; Lim, Shing Min; Yew, Sok Yee

    2015-10-01

    Drug packaging is commonly submitted to the Forensic Chemistry and Physics Laboratory of the Health Sciences Authority, Singapore, for examination. The drugs seized are often packaged in plastic bags. These bags are examined for linkages to provide law enforcement with useful associations between the traffickers and drug abusers. The plastic bags submitted may include snap-lock bags, some with a red band located above the snap-lock closure and some without. Current techniques for examination involve looking at the physical characteristics (dimensions, thickness and polarising patterns) and manufacturing marks of these bags. In cases where manufacturing marks on the main body of the bags are poor or absent, the manufacturing characteristics present on the red band can be examined. A study involving approximately 1000 bags was conducted to better understand the variations in the manufacturing characteristics of the red band. This understanding is crucial in helping to determine associations/eliminations between bags. Two instrumental techniques, namely differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FT-IR) were explored to evaluate the effectiveness of examining the chemical composition to discriminate the bags. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  18. The challenge of turbulent acceleration of relativistic particles in the intra-cluster medium

    NASA Astrophysics Data System (ADS)

    Brunetti, Gianfranco

    2016-01-01

    Acceleration of cosmic-ray electrons (CRe) in the intra-cluster medium (ICM) is probed by radio observations that detect diffuse, megaparsec-scale, synchrotron sources in a fraction of galaxy clusters. Giant radio halos are the most spectacular manifestations of non-thermal activity in the ICM and are currently explained assuming that turbulence, driven during massive cluster-cluster mergers, reaccelerates CRe at several giga-electron volts. This scenario implies a hierarchy of complex mechanisms in the ICM that drain energy from large scales into electromagnetic fluctuations in the plasma and collisionless mechanisms of particle acceleration at much smaller scales. In this paper we focus on the physics of acceleration by compressible turbulence. The spectrum and damping mechanisms of the electromagnetic fluctuations, and the mean free path (mfp) of CRe, are the most relevant ingredients that determine the efficiency of acceleration. These ingredients in the ICM are, however, poorly known, and we show that calculations of turbulent acceleration are also sensitive to these uncertainties. On the other hand this fact implies that the non-thermal properties of galaxy clusters probe the complex microphysics and the weakly collisional nature of the ICM.

  19. Overview of accelerators with potential use in homeland security

    DOE PAGES

    Garnett, Robert W.

    2015-06-18

    Quite a broad range of accelerators have been applied to solving many of the challenging problems related to homeland security and defense. These accelerator systems range from relatively small, simple, and compact, to large and complex, based on the specific application requirements. They have been used or proposed as sources of primary and secondary probe beams for applications such as radiography and to induce specific reactions that are key signatures for detecting conventional explosives or fissile material. A brief overview and description of these accelerator systems, their specifications, and application will be presented. Some recent technology trends will also bemore » discussed.« less

  20. Electrokinetic acceleration of DNA hybridization in microsystems.

    PubMed

    Lei, Kin Fong; Wang, Yun-Hsiang; Chen, Huai-Yi; Sun, Jia-Hong; Cheng, Ji-Yen

    2015-06-01

    In this work, electrokinetic acceleration of DNA hybridization was investigated by different combinations of frequencies and amplitudes of actuating electric signals. Because the frequencies from low to high can induce different kinds of electrokinetic forces, i.e., electroosmotic to electrothermal forces, this work provides an in-depth investigation of electrokinetic enhanced hybridization. Concentric circular Cr/Au microelectrodes of 350 µm in diameter were fabricated on a glass substrate and probe DNA was immobilized on the electrode surface. Target DNA labeled with fluorescent dyes suspending in solution was then applied to the electrode. Different electrokinetic forces were induced by the application of different electric signals to the circular microelectrodes. Local microfluidic vortexes were generated to increase the collision efficiency between the target DNA suspending in solution and probe DNA immobilized on the electrode surface. DNA hybridization on the electrode surface could be accelerated by the electrokinetic forces. The level of hybridization was represented by the fluorescent signal intensity ratio. Results revealed that such 5-min dynamic hybridization increased 4.5 fold of signal intensity ratio as compared to a 1-h static hybridization. Moreover, dynamic hybridization was found to have better differentiation ability between specific and non-specific target DNA. This study provides a strategy to accelerate DNA hybridization in microsystems. Copyright © 2015 Elsevier B.V. All rights reserved.

  1. Naked singularities as particle accelerators

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

    Patil, Mandar; Joshi, Pankaj S.

    We investigate here the particle acceleration by naked singularities to arbitrarily high center of mass energies. Recently it has been suggested that black holes could be used as particle accelerators to probe the Planck scale physics. We show that the naked singularities serve the same purpose and probably would do better than their black hole counterparts. We focus on the scenario of a self-similar gravitational collapse starting from a regular initial data, leading to the formation of a globally naked singularity. It is seen that when particles moving along timelike geodesics interact and collide near the Cauchy horizon, the energymore » of collision in the center of mass frame will be arbitrarily high, thus offering a window to Planck scale physics.« less

  2. Irradiation qualification testing of SNAP-10A components

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

    Chesavage, A. J.

    1964-02-04

    Selected SNAP 10A components were irradiated to about 10{sup14} nvt and 5{times} 10{sup 7} r at an average temperature of 136{degrees}F in a nominal vacuum of 2 {times} 10{sup {minus}5} torr. The components were operated periodically and the electrical characteristics recorded. Pre-irradiationand post-irradiation tests were conducted. Catastropic degradation occurred only in the low-level neutron detection system and about 1.5 {times} 10{sup 13} nvt and in the high-level neutron power supply at about 6{times} 10{sup 12} nvt. Marginal degradation occurred in the fusistors and in the silicone rubber insert material in connectors. The relays, low-voltage trip devices, expansion compensator position demodulator,more » resistance thermometer sensor and bridge, and the gamma detection system opearted within their respective specifications during and after irradiation. The insulation resistance of all components was adeqauate during and after irradiation.« less

  3. The Snapping Elbow Syndrome as a Reason for Chronic Elbow Neuralgia in a Tennis Player - MR, US and Sonoelastography Evaluation.

    PubMed

    Łasecki, Mateusz; Olchowy, Cyprian; Pawluś, Aleksander; Zaleska-Dorobisz, Urszula

    2014-01-01

    Ulnar neuropathy is the second most common peripheral nerve neuropathy after median neuropathy, with an incidence of 25 cases per 100 000 men and 19 cases per 100 000 women each year. Skipping (snapping) elbow syndrome is an uncommon cause of pain in the posterior-medial elbow area, sometimes complicated by injury of the ulnar nerve. One of the reason is the dislocation of the abnormal insertion of the medial triceps head over the medial epicondyle during flexion and extension movements. Others are: lack of the Osboune fascia leading to ulnar nerve instability and focal soft tissue tumors (fibromas, lipomas, etc). Recurrent subluxation of the nerve at the elbow results in a tractional and frictional neuritis with classical symptoms of peripheral neuralgia. As far as we know snapping triceps syndrome had never been evaluated in sonoelastography. A 28yo semi-professional left handed tennis player was complaining about pain in posterior-medial elbow area. Initial US examination suggest golfers elbow syndrome which occurs quite commonly and has a prevalence of 0.3-0.6% in males and 0-3-1.1% in women and may be associated (approx. 50% of cases) with ulnar neuropathy. However subsequently made MRI revealed unusual distal triceps anatomy, moderate ulnar nerve swelling and lack of medial epicondylitis symptoms. Followed (second) US examination and sonoelastography have detected slipping of the both ulnar nerve and the additional band of the medial triceps head. Snapping elbow syndrome is a poorly known medical condition, sometimes misdiagnosed as the medial epicondylitis. It describes a broad range of pathologies and anatomical abnormalities. One of the most often reasons is the slipping of the ulnar nerve as the result of the Osborne fascia/anconeus epitrochlearis muscle absence. Simultaneously presence of two or more "snapping reasons" is rare but should be always taken under consideration. There are no sonoelastography studies describing golfers elbow syndrome

  4. A Prospective, Multicenter, Single-Blind Study Assessing Indices of SNAP II Versus BIS VISTA on Surgical Patients Undergoing General Anesthesia

    PubMed Central

    Bergese, Sergio D; Puente, Erika G; Marcus, R-Jay L; Krohn, Randall J; Docsa, Steven; Soto, Roy G; Candiotti, Keith A

    2017-01-01

    Background Traditionally, anesthesiologists have relied on nonspecific subjective and objective physical signs to assess patients’ comfort level and depth of anesthesia. Commercial development of electrical monitors, which use low- and high-frequency electroencephalogram (EEG) signals, have been developed to enhance the assessment of patients’ level of consciousness. Multiple studies have shown that monitoring patients’ consciousness levels can help in reducing drug consumption, anesthesia-related adverse events, and recovery time. This clinical study will provide information by simultaneously comparing the performance of the SNAP II (a single-channel EEG device) and the bispectral index (BIS) VISTA (a dual-channel EEG device) by assessing their efficacy in monitoring different anesthetic states in patients undergoing general anesthesia. Objective The primary objective of this study is to establish the range of index values for the SNAP II corresponding to each anesthetic state (preinduction, loss of response, maintenance, first purposeful response, and extubation). The secondary objectives will assess the range of index values for BIS VISTA corresponding to each anesthetic state compared to published BIS VISTA range information, and estimate the area under the curve, sensitivity, and specificity for both devices. Methods This is a multicenter, prospective, double-arm, parallel assignment, single-blind study involving patients undergoing elective surgery that requires general anesthesia. The study will include 40 patients and will be conducted at the following sites: The Ohio State University Medical Center (Columbus, OH); Northwestern University Prentice Women's Hospital (Chicago, IL); and University of Miami Jackson Memorial Hospital (Miami, FL). The study will assess the predictive value of SNAP II versus BIS VISTA indices at various anesthetic states in patients undergoing general anesthesia (preinduction, loss of response, maintenance, first purposeful

  5. Neonatal mannequin comparison of the Upright self-inflating bag and snap-fit mask versus standard resuscitators and masks: leak, applied load and tidal volumes.

    PubMed

    Rafferty, Anthony Richard; Johnson, Lucy; Davis, Peter G; Dawson, Jennifer Anne; Thio, Marta; Owen, Louise S

    2017-11-30

    Neonatal mask ventilation is a difficult skill to acquire and maintain. Mask leak is common and can lead to ineffective ventilation. The aim of this study was to determine whether newly available neonatal self-inflating bags and masks could reduce mask leak without additional load being applied to the face. Forty operators delivered 1 min episodes of mask ventilation to a mannequin using the Laerdal Upright Resuscitator, a standard Laerdal infant resuscitator (Laerdal Medical) and a T-Piece Resuscitator (Neopuff), using both the Laerdal snap-fit face mask and the standard Laerdal size 0/1 face mask (equivalent sizes). Participants were asked to use pressure sufficient to achieve 'appropriate' chest rise. Leak, applied load, airway pressure and tidal volume were measured continuously. Participants were unaware that load was being recorded. There was no difference in mask leak between resuscitation devices. Leak was significantly lower when the snap-fit mask was used with all resuscitation devices, compared with the standard mask (14% vs 37% leak, P<0.01). The snap-fit mask was preferred by 83% of participants. The device-mask combinations had no significant effect on applied load. The Laerdal Upright Resuscitator resulted in similar leak to the other resuscitation devices studied, and did not exert additional load to the face and head. The snap-fit mask significantly reduced overall leak with all resuscitation devices and was the mask preferred by participants. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  6. The expression of a naturally occuriing truncated allele of an alpha-SNAP gene suppresses plant parasitic nematode infection

    USDA-ARS?s Scientific Manuscript database

    rhg1, defined within a 67 kb region of DNA on chromosome 18, is a major quantitative trait locus (QTL) in Glycine max (soybean) providing defense to the soybean cyst nematode (Heterodera glycines). Transcriptional mapping experiments identified an alpha soluble NSF attachment protein (alpha-SNAP) wi...

  7. Compressive Acceleration of Solar Energetic Particles within Coronal Mass Ejections: Observations and Theory Relevant to the Solar Probe Plus and Solar Orbiter Missions

    NASA Astrophysics Data System (ADS)

    Roelof, E. C.

    2015-12-01

    observational technique by which (divV) may be extracted directly from coronograph white-light movies of out-going CMEs, thus offering observational closure of the new theory for SEP acceleration/injection that should be relevant to the Solar Probe Plus and Solar Orbiter missions.

  8. Organochlorine pesticides, PCBs, dibenzodioxin, and furan concentrations in common snapping turtle eggs (Chelydra serpentina serpentina) in Akwesasne, Mohawk Territory, Ontario, Canada.

    PubMed

    de Solla, S R; Bishop, C A; Lickers, H; Jock, K

    2001-04-01

    Subsamples of eight clutches of common snapping turtle eggs (Chelydra serpentina serpentina) were collected from four sites from the territory of the Mohawk Nation, Akwesasne, on the shore of the St. Lawrence River. Egg contents were analyzed for organochlorine pesticides, polychlorinated biphenyls (PCBs), dibenzodioxins, and furans. The sites were 2 to 13 km downstream from PCB-contaminated landfill sites. Maximum concentrations of total PCBs in snapping turtle clutches were extremely high, and ranged from 2 378.2 ng/g to 737 683 ng/g (wet weight) and are among the highest recorded in any tissue of a free-ranging animal. Similarly, in a pooled sample of eggs from all four sites, the summed concentrations of non-ortho PCBs (n = 6 congeners) was also very high at 54.54 ng/g and the summed dioxin and furan concentrations (n = 11 congeners) was 85.8 ng/g. Sum organochlorine pesticide levels varied from 28 to 2,264 ng/g among the four sites. The levels of PCBs found in turtle eggs exceed concentrations associated with developmental problems and reduced hatching success in snapping turtles and other species and also exceed the Canadian tissue residue guidelines for toxic equivalency concentrations. The extremely high levels of organochlorine contaminants demonstrate the high degree of contamination in the environment in the Akwesasne area.

  9. Development and Validation of Big Four Personality Scales for the Schedule for Nonadaptive and Adaptive Personality-2nd Edition (SNAP-2)

    PubMed Central

    Calabrese, William R.; Rudick, Monica M.; Simms, Leonard J.; Clark, Lee Anna

    2012-01-01

    Recently, integrative, hierarchical models of personality and personality disorder (PD)—such as the Big Three, Big Four and Big Five trait models—have gained support as a unifying dimensional framework for describing PD. However, no measures to date can simultaneously represent each of these potentially interesting levels of the personality hierarchy. To unify these measurement models psychometrically, we sought to develop Big Five trait scales within the Schedule for Adaptive and Nonadaptive Personality–2nd Edition (SNAP-2). Through structural and content analyses, we examined relations between the SNAP-2, Big Five Inventory (BFI), and NEO-Five Factor Inventory (NEO-FFI) ratings in a large data set (N = 8,690), including clinical, military, college, and community participants. Results yielded scales consistent with the Big Four model of personality (i.e., Neuroticism, Conscientiousness, Introversion, and Antagonism) and not the Big Five as there were insufficient items related to Openness. Resulting scale scores demonstrated strong internal consistency and temporal stability. Structural and external validity was supported by strong convergent and discriminant validity patterns between Big Four scale scores and other personality trait scores and expectable patterns of self-peer agreement. Descriptive statistics and community-based norms are provided. The SNAP-2 Big Four Scales enable researchers and clinicians to assess personality at multiple levels of the trait hierarchy and facilitate comparisons among competing “Big Trait” models. PMID:22250598

  10. Simulated Prompt Acceleration of Multi-MeV Electrons by the 17 March 2015 Interplanetary Shock

    NASA Astrophysics Data System (ADS)

    Hudson, Mary; Jaynes, Allison; Kress, Brian; Li, Zhao; Patel, Maulik; Shen, Xiao-Chen; Thaller, Scott; Wiltberger, Michael; Wygant, John

    2017-10-01

    Prompt enhancement of relativistic electron flux at L = 3-5 has been reported from Van Allen Probes Relativistic Electron Proton Telescope (REPT) measurements associated with the 17 March 2015 interplanetary shock compression of the dayside magnetosphere. Acceleration by ˜1 MeV is inferred on less than a drift timescale as seen in prior shock compression events, which launch a magnetosonic azimuthal electric field impulse tailward. This impulse propagates from the dayside around the flanks accelerating electrons in drift resonance at the dusk flank. Such longitudinally localized acceleration events produce a drift echo signature which was seen at >1 MeV energy on both Van Allen Probe spacecraft, with sustained observations by Probe B outbound at L = 5 at 2100 MLT at the time of impulse arrival, measured by the Electric Fields and Waves instrument. MHD test particle simulations are presented which reproduce drift echo features observed in the REPT measurements at Probe B, including the energy and pitch angle dependence of drift echoes observed. While the flux enhancement was short lived for this event due to subsequent inward motion of the magnetopause, stronger events with larger electric field impulses, as observed in March 1991 and the Halloween 2003 storm, produce enhancements which can be quantified by the inward radial transport and energization determined by the induction electric field resulting from dayside compression.

  11. Development and validation of Big Four personality scales for the Schedule for Nonadaptive and Adaptive Personality--Second Edition (SNAP-2).

    PubMed

    Calabrese, William R; Rudick, Monica M; Simms, Leonard J; Clark, Lee Anna

    2012-09-01

    Recently, integrative, hierarchical models of personality and personality disorder (PD)--such as the Big Three, Big Four, and Big Five trait models--have gained support as a unifying dimensional framework for describing PD. However, no measures to date can simultaneously represent each of these potentially interesting levels of the personality hierarchy. To unify these measurement models psychometrically, we sought to develop Big Five trait scales within the Schedule for Nonadaptive and Adaptive Personality--Second Edition (SNAP-2). Through structural and content analyses, we examined relations between the SNAP-2, the Big Five Inventory (BFI), and the NEO Five-Factor Inventory (NEO-FFI) ratings in a large data set (N = 8,690), including clinical, military, college, and community participants. Results yielded scales consistent with the Big Four model of personality (i.e., Neuroticism, Conscientiousness, Introversion, and Antagonism) and not the Big Five, as there were insufficient items related to Openness. Resulting scale scores demonstrated strong internal consistency and temporal stability. Structural validity and external validity were supported by strong convergent and discriminant validity patterns between Big Four scale scores and other personality trait scores and expectable patterns of self-peer agreement. Descriptive statistics and community-based norms are provided. The SNAP-2 Big Four Scales enable researchers and clinicians to assess personality at multiple levels of the trait hierarchy and facilitate comparisons among competing big-trait models. PsycINFO Database Record (c) 2012 APA, all rights reserved.

  12. Programmable snapping composites with bio-inspired architecture.

    PubMed

    Schmied, Jascha U; Le Ferrand, Hortense; Ermanni, Paolo; Studart, André R; Arrieta, Andres F

    2017-03-13

    The development of programmable self-shaping materials enables the onset of new and innovative functionalities in many application fields. Commonly, shape adaptation is achieved by exploiting diffusion-driven swelling or nano-scale phase transition, limiting the change of shape to slow motion predominantly determined by the environmental conditions and/or the materials specificity. To address these shortcomings, we report shape adaptable programmable shells that undergo morphing via a snap-through mechanism inspired by the Dionaea muscipula leaf, known as the Venus fly trap. The presented shells are composite materials made of epoxy reinforced by stiff anisotropic alumina micro-platelets oriented in specific directions. By tailoring the microstructure via magnetically-driven alignment of the platelets, we locally tune the pre-strain and stiffness anisotropy of the composite. This novel approach enables the fabrication of complex shapes showing non-orthotropic curvatures and stiffness gradients, radically extending the design space when compared to conventional long-fibre reinforced multi-stable composites. The rare combination of large stresses, short actuation times and complex shapes, results in hinge-free artificial shape adaptable systems with large design freedom for a variety of morphing applications.

  13. High levels of maternally transferred mercury disrupt magnetic responses of snapping turtle hatchlings (Chelydra serpentina).

    PubMed

    Landler, Lukas; Painter, Michael S; Coe, Brittney Hopkins; Youmans, Paul W; Hopkins, William A; Phillips, John B

    2017-09-01

    The Earth's magnetic field is involved in spatial behaviours ranging from long-distance migration to non-goal directed behaviours, such as spontaneous magnetic alignment (SMA). Mercury is a harmful pollutant most often generated from anthropogenic sources that can bio-accumulate in animal tissue over a lifetime. We compared SMA of hatchling snapping turtles from mothers captured at reference (i.e., low mercury) and mercury contaminated sites. Reference turtles showed radio frequency-dependent SMA along the north-south axis, consistent with previous studies of SMA, while turtles with high levels of maternally inherited mercury failed to show consistent magnetic alignment. In contrast, there was no difference between reference and mercury exposed turtles on standard performance measures. The magnetic field plays an important role in animal orientation behaviour and may also help to integrate spatial information from a variety of sensory modalities. As a consequence, mercury may compromise the performance of turtles in a wide variety of spatial tasks. Future research is needed to determine the threshold for mercury effects on snapping turtles, whether mercury exposure compromises spatial behaviour of adult turtles, and whether mercury has a direct effect on the magnetoreception mechanism(s) that mediate SMA or a more general effect on the nervous system. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Effects of Management Practices on Meloidogyne incognita and Snap Bean Yield.

    PubMed

    Smittle, D A; Johnson, A W

    1982-01-01

    Phenamiphos applied at 6.7 kg ai/ha through a solid set or a center pivot irrigation system with 28 mm of water effectively controlled root-knot nematodes, Meloidogyne incognita, and resulted in greater snap bean growth and yields irrespective of growing season, tillage method, or cover crop system. The percentage yield increases attributed to this method of M. incognita control over nontreated controls were 45% in the spring crop, and 90% and 409% in the fall crops following winter rye and fallow, respectively. Root galling was not affected by tillage systems or cover crop, but disk tillage resulted in over 50% reduction in bean yield compared with yields from the subsoil-bed tillage system.

  15. Thermo-physics technical note No. 37: SNAP- 10A, Stainless Steel-316 vessel wall ablation. Final report

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

    Montgomery, L.D.

    1964-12-07

    The altitudes and times of ablation have been determined for the SNAP-10A, SS-316 vessel wall reentering under various conditions. The results are confined to one typical location on the reactor and to one typical reentry trajectory. The location is the side wall of the vessel and the trajectory is the one used in NAA-SR-8303.

  16. The reduced serum free triiodothyronine and increased dorsal hippocampal SNAP-25 and Munc18-1 had existed in middle-aged CD-1 mice with mild spatial cognitive impairment.

    PubMed

    Cao, Lei; Jiang, Wei; Wang, Fang; Yang, Qi-Gang; Wang, Chao; Chen, Yong-Ping; Chen, Gui-Hai

    2013-12-02

    Changes of synaptic proteins in highlighted brain regions and decreased serum thyroid hormones (THs) have been implied in age-related learning and memory decline. Previously, we showed significant pairwise correlations among markedly impaired spatial learning and memory ability, decreased serum free triiodothyronine (FT3) and increased hippocampal SNAP-25 and Munc18-1 in old Kunming mice. However, whether these changes and the correlations occur in middle-age mice remains unclear. Since this age is one of the best stages to study age-related cognitive decline, we explored the spatial learning and memory ability, serum THs, cerebral SNAP-25 and Munc18-1 levels and their relationships of middle-aged mice in this study. The learning and memory abilities of 35 CD-1 mice (19 mice aged 6 months and 16 mice aged 12 months) were measured with a radial six-arm water maze (RAWM). The SNAP-25 and Munc18-1 levels were semi-quantified by Western blotting and the serum THs were detected by radioimmunoassay. The results showed the middle-aged mice had decreased serum FT3, increased dorsal hippocampal (DH) SNAP-25 and Munc18-1, and many or long number of errors and latency in both learning and memory phases of the RAWM. The Pearson's correlation test showed that the DH SANP-25 and Munc18-1 levels were positively correlated with the number of errors and latency in learning phases of the RAWM. Meanwhile, the DH SANP-25 and Munc18-1 levels negatively correlated with the serum FT3 level. These results suggested that reduced FT3 with increased DH SNAP-25 and Munc18-1 levels might be involved in the spatial learning ability decline in the middle-aged mice. © 2013 Elsevier B.V. All rights reserved.

  17. A Prospective, Multicenter, Single-Blind Study Assessing Indices of SNAP II Versus BIS VISTA on Surgical Patients Undergoing General Anesthesia.

    PubMed

    Bergese, Sergio D; Uribe, Alberto A; Puente, Erika G; Marcus, R-Jay L; Krohn, Randall J; Docsa, Steven; Soto, Roy G; Candiotti, Keith A

    2017-02-03

    Traditionally, anesthesiologists have relied on nonspecific subjective and objective physical signs to assess patients' comfort level and depth of anesthesia. Commercial development of electrical monitors, which use low- and high-frequency electroencephalogram (EEG) signals, have been developed to enhance the assessment of patients' level of consciousness. Multiple studies have shown that monitoring patients' consciousness levels can help in reducing drug consumption, anesthesia-related adverse events, and recovery time. This clinical study will provide information by simultaneously comparing the performance of the SNAP II (a single-channel EEG device) and the bispectral index (BIS) VISTA (a dual-channel EEG device) by assessing their efficacy in monitoring different anesthetic states in patients undergoing general anesthesia. The primary objective of this study is to establish the range of index values for the SNAP II corresponding to each anesthetic state (preinduction, loss of response, maintenance, first purposeful response, and extubation). The secondary objectives will assess the range of index values for BIS VISTA corresponding to each anesthetic state compared to published BIS VISTA range information, and estimate the area under the curve, sensitivity, and specificity for both devices. This is a multicenter, prospective, double-arm, parallel assignment, single-blind study involving patients undergoing elective surgery that requires general anesthesia. The study will include 40 patients and will be conducted at the following sites: The Ohio State University Medical Center (Columbus, OH); Northwestern University Prentice Women's Hospital (Chicago, IL); and University of Miami Jackson Memorial Hospital (Miami, FL). The study will assess the predictive value of SNAP II versus BIS VISTA indices at various anesthetic states in patients undergoing general anesthesia (preinduction, loss of response, maintenance, first purposeful response, and extubation). The SNAP

  18. Internal Snapping Hip Syndrome: Incidence of Multiple-Tendon Existence and Outcome After Endoscopic Transcapsular Release.

    PubMed

    Ilizaliturri, Victor M; Suarez-Ahedo, Carlos; Acuña, Marco

    2015-10-01

    To report the frequency of presentation of bifid or multiple iliopsoas tendons in patients who underwent endoscopic release for internal snapping hip syndrome (ISHS) and to compare both groups. A consecutive series of patients with ISHS were treated with endoscopic transcapsular release of the iliopsoas tendon at the central compartment and prospectively followed up. The inclusion criteria were patients with a diagnosis of ISHS with failure of conservative treatment. During the procedure, the presence of a bifid tendon was intentionally looked for. Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores were evaluated preoperatively and at last follow-up. Four patients presented with a bifid tendon and one patient had 3 tendons. At a minimum of 12 months' follow-up, the presence of snapping recurrence was evaluated and the WOMAC scores were compared between both groups. Among 279 hip arthroscopies, 28 patients underwent central transcapsular iliopsoas tendon release. The mean age was 29.25 years (range, 16 to 65 years; 6 left and 22 right hips). Group 1 included 5 patients with multiple tendons; the remaining patients formed group 2 (n = 23). None of the patients presented with ISHS recurrence. The mean WOMAC score in group 1 was 39 points (95% confidence interval [CI], 26.2 to 55.4 points) preoperatively and 73.6 points (95% CI, 68.4 to 79.6 points) at last follow-up. In group 2 the mean WOMAC score was 47.21 points (95% CI, 44.4 to 58.2 points) preoperatively and 77.91 points (95% CI, 67.8 to 83.4 points) at last follow-up. We identified a bifid tendon retrospectively on magnetic resonance arthrograms in 3 of the 5 cases that were found to have multiple tendons during surgery. None of these were recognized before the procedures. In this series the surgeon intentionally looked for multiple tendons, which were found in 17.85% of the cases. Clinical results in patients with single- and multiple-tendon snapping seem to be similarly adequate

  19. Two Disease-Causing SNAP-25B Mutations Selectively Impair SNARE C-terminal Assembly.

    PubMed

    Rebane, Aleksander A; Wang, Bigeng; Ma, Lu; Qu, Hong; Coleman, Jeff; Krishnakumar, Shyam; Rothman, James E; Zhang, Yongli

    2018-02-16

    Synaptic exocytosis relies on assembly of three soluble N-ethylmaleimide-sensitive factor attachment receptor (SNARE) proteins into a parallel four-helix bundle to drive membrane fusion. SNARE assembly occurs by stepwise zippering of the vesicle-associated SNARE (v-SNARE) onto a binary SNARE complex on the target plasma membrane (t-SNARE). Zippering begins with slow N-terminal association followed by rapid C-terminal zippering, which serves as a power stroke to drive membrane fusion. SNARE mutations have been associated with numerous diseases, especially neurological disorders. It remains unclear how these mutations affect SNARE zippering, partly due to difficulties to quantify the energetics and kinetics of SNARE assembly. Here, we used single-molecule optical tweezers to measure the assembly energy and kinetics of SNARE complexes containing single mutations I67T/N in neuronal SNARE synaptosomal-associated protein of 25kDa (SNAP-25B), which disrupt neurotransmitter release and have been implicated in neurological disorders. We found that both mutations significantly reduced the energy of C-terminal zippering by ~10 k B T, but did not affect N-terminal assembly. In addition, we observed that both mutations lead to unfolding of the C-terminal region in the t-SNARE complex. Our findings suggest that both SNAP-25B mutations impair synaptic exocytosis by destabilizing SNARE assembly, rather than stabilizing SNARE assembly as previously proposed. Therefore, our measurements provide insights into the molecular mechanism of the disease caused by SNARE mutations. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Microwaves and particle accelerators: a fundamental link

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

    Chattopadhyay, Swapan

    2011-07-01

    John Cockcroft's splitting of the atom and Ernest Lawrence's invention of the cyclotron in the first half of the twentieth century ushered in the grand era of ever higher energy particle accelerators to probe deeper into matter. It also forged a link, bonding scientific discovery with technological innovation that continues today in the twenty first century. The development of radar and high power vacuum electronics, especially microwave power tubes like the magnetrons and the klystrons in the pre-second world war era, was instrumental in the rapid development of circular and linear charged particle accelerators in the second half of themore » twentieth century. We had harnessed the powerful microwave radio-frequency sources from few tens of MHz to up to 90 GHz spanning L-band to W-band frequencies. Simultaneously in the second half of the twentieth century, lasers began to offer very first opportunities of controlling charged particles at smaller resolutions on the scale of wavelengths of visible light. We also witnessed in this period the emergence of the photon and neutron sciences driven by accelerators built-by-design producing tailored and ultra-bright pulses of bright photons and neutrons to probe structure and function of matter from aggregate to individual molecular and atomic scales in unexplored territories in material and life sciences. As we enter the twenty first century, the race for ever higher energies, brightness and luminosity to probe atto-metric and atto-second domains of the ultra-small structures and ultra-fast processes continues. These developments depend crucially on yet further advancements in the production and control of high power and high frequency microwaves and light sources, often intricately coupled in their operation to the high energy beams themselves. We give a glimpse of the recent developments and innovations in the electromagnetic production and control of charged particle beams in the service of science and society

  1. VAMP-2, SNAP-25A/B and syntaxin-1 in glutamatergic and GABAergic synapses of the rat cerebellar cortex

    PubMed Central

    2011-01-01

    Background The aim of this study was to assess the distribution of key SNARE proteins in glutamatergic and GABAergic synapses of the adult rat cerebellar cortex using light microscopy immunohistochemical techniques. Analysis was made of co-localizations of vGluT-1 and vGluT-2, vesicular transporters of glutamate and markers of glutamatergic synapses, or GAD, the GABA synthetic enzyme and marker of GABAergic synapses, with VAMP-2, SNAP-25A/B and syntaxin-1. Results The examined SNARE proteins were found to be diffusely expressed in glutamatergic synapses, whereas they were rarely observed in GABAergic synapses. However, among glutamatergic synapses, subpopulations which did not contain VAMP-2, SNAP-25A/B and syntaxin-1 were detected. They included virtually all the synapses established by terminals of climbing fibres (immunoreactive for vGluT-2) and some synapses established by terminals of parallel and mossy fibres (immunoreactive for vGluT-1, and for vGluT-1 and 2, respectively). The only GABA synapses expressing the SNARE proteins studied were the synapses established by axon terminals of basket neurons. Conclusion The present study supplies a detailed morphological description of VAMP-2, SNAP-25A/B and syntaxin-1 in the different types of glutamatergic and GABAergic synapses of the rat cerebellar cortex. The examined SNARE proteins characterize most of glutamatergic synapses and only one type of GABAergic synapses. In the subpopulations of glutamatergic and GABAergic synapses lacking the SNARE protein isoforms examined, alternative mechanisms for regulating trafficking of synaptic vesicles may be hypothesized, possibly mediated by different isoforms or homologous proteins. PMID:22094010

  2. Dark Signal Characterization of 1.7 micron cutoff devices for SNAP

    NASA Astrophysics Data System (ADS)

    Smith, R. M.; SNAP Collaboration

    2004-12-01

    We report initial progress characterizing non-photometric sources of error -- dark current, noise, and zero point drift -- for 1.7 micron cutoff HgCdTe and InGaAs detectors under development by Raytheon, Rockwell, and Sensors Unlimited for SNAP. Dark current specifications can already be met with several detector types. Changes to the manufacturing process are being explored to improve the noise reduction available through multiple sampling. In some cases, a significant number of pixels suffer from popcorn noise, with a few percent of all pixels exhibiting a ten fold noise increase. A careful study of zero point drifts is also under way, since these errors can dominate dark current, and may contribute to the noise degradation seen in long exposures.

  3. Progress In Plasma Accelerator Development for Dynamic Formation of Plasma Liners

    NASA Technical Reports Server (NTRS)

    Thio, Y. C. Francis; Eskridge, Richard; Martin, Adam; Smith, James; Lee, Michael; Cassibry, Jason T.; Griffin, Steven; Rodgers, Stephen L. (Technical Monitor)

    2002-01-01

    An experimental plasma accelerator for magnetic target fusion (MTF) applications under development at the NASA Marshall Space Flight Center is described. The accelerator is a coaxial pulsed plasma thruster (Figure 1). It has been tested experimentally and plasma jet velocities of approx.50 km/sec have been obtained. The plasma jet has been photographed with 10-ns exposure times to reveal a stable and repeatable plasma structure (Figure 2). Data for velocity profile information has been obtained using light pipes and magnetic probes embedded in the gun walls to record the plasma and current transit respectively at various barrel locations. Preliminary spatially resolved spectral data and magnetic field probe data are also presented. A high speed triggering system has been developed and tested as a means of reducing the gun "jitter". This jitter is being characterized and future work for second generation "ultra-low jitter" gun development is being identified.

  4. Nasa's Solar Probe Plus Mission and Implications for the Theoretical Understanding of the Heliosphere

    NASA Astrophysics Data System (ADS)

    Velli, Marco

    2012-07-01

    Solar Probe Plus (SPP), one of the most challenging missions to understand the origins of the Heliosphere, will carry a payload consisting of plasma and energetic particle detectors, elec- tromagnetic field antennas and magnetometers, and a white light imager, to the unexplored regions extending from 70 to 8.5 solar radii (0.3 to 0.05 AU) from the photosphere of the Sun. Solar Probe Plus's goals are to understand the extended heating of the solar corona and acceleration of the solar wind,the origins of solar wind structures including high and low speed streams, and the origins of energetic particle acceleration in Coronal Mass Ejections and CMEs. In addition, combined measurements from the white light imager and the EM field antennas will allow the first direct measurements of dust deep in the inner solar system. This presentation will provide a broad context for the mission objectives and measurements and illustrate the likely progress SPP will bring to the understanding of the Heliosphere, stellar winds, and the fundamental physics of particle acceleration, reconnection, collisionless shocks and turbulence in space and astrophysical plasmas.

  5. Characterization of microsatellite DNA markers for the alligator snapping turtle, Macrochelys temminckii: Primer note

    USGS Publications Warehouse

    Hackler, J.C.; Van Den Bussche, Ronald A.; Leslie, David M.

    2007-01-01

    Two trinucleotide and seven tetranucleotide microsatellite loci were isolated from an alligator snapping turtle Macrochelys temminckii. To assess the degree of variability in these nine microsatellite loci, we genotyped 174 individuals collected from eight river drainage basins in the southeastern USA. These markers revealed a moderate degree of allelic diversity (six to 16 alleles per locus) and observed heterozygosity (0.166-0.686). These polymorphic microsatellite loci provide powerful tools for population genetic studies for a species that is afforded some level of conservation protection in every state in which it occurs. ?? 2006 The Authors.

  6. Solar Probe Plus: A mission to touch the sun

    NASA Astrophysics Data System (ADS)

    Kinnison, J.; Lockwood, M. K.; Fox, N.; Conde, R.; Driesman, A.

    Solar Probe Plus (SPP), currently in Phase B, will be the first mission to fly into the low solar corona, revealing how the corona is heated and the solar wind is accelerated, solving two fundamental mysteries that have been top priority science goals since such a mission was first proposed in 1958. The scale and concept of such a mission has been revised at intervals since that time, yet the core has always been a close encounter with the Sun. SPP uses an innovative mission design, significant technology development and a risk-reducing engineering development to meet the SPP science objectives: 1) determine the structure and dynamics of the magnetic fields at the sources of the fast and slow solar wind, 2) trace the flow of energy that heats the corona and accelerates the solar wind. and 3) determine what mechanisms accelerate and transport energetic particles. In this paper, we present the Solar Probe Plus mission along with a brief comparison with some previous concepts for such a mission, and discuss the trade studies that led to the SPP implementation. We present a summary of the challenges associated with operation in the solar encounter environment and discuss the technology development and engineering trade studies to compose a mission that will not only survive this environment, but will provide the data needed to answer the science questions that have remained unanswered to date.

  7. The effect of blood acceleration on the ultrasound power Doppler spectrum

    NASA Astrophysics Data System (ADS)

    Matchenko, O. S.; Barannik, E. A.

    2017-09-01

    The purpose of the present work was to study the influence of blood acceleration and time window length on the power Doppler spectrum for Gaussian ultrasound beams. The work has been carried out on the basis of continuum model of the ultrasound scattering from inhomogeneities in fluid flow. Correlation function of fluctuations has been considered for uniformly accelerated scatterers, and the resulting power Doppler spectra have been calculated. It is shown that within the initial phase of systole uniformly accelerated slow blood flow in pulmonary artery and aorta tends to make the correlation function about 4.89 and 7.83 times wider, respectively, than the sensitivity function of typical probing system. Given peak flow velocities, the sensitivity function becomes, vice versa, about 4.34 and 3.84 times wider, respectively, then the correlation function. In these limiting cases, the resulting spectra can be considered as Gaussian. The optimal time window duration decreases with increasing acceleration of blood flow and equals to 11.62 and 7.54 ms for pulmonary artery and aorta, respectively. The width of the resulting power Doppler spectrum is shown to be defined mostly by the wave vector of the incident field, the duration of signal and the acceleration of scatterers in the case of low flow velocities. In the opposite case geometrical properties of probing field and the average velocity itself are more essential. In the sense of signal-noise ratio, the optimal duration of time window can be found. Abovementioned results may contribute to the improved techniques of Doppler ultrasound diagnostics of cardiovascular system.

  8. Energetics of small electron acceleration episodes in the solar corona from radio noise storm observations

    NASA Astrophysics Data System (ADS)

    James, Tomin; Subramanian, Prasad

    2018-05-01

    Observations of radio noise storms can act as sensitive probes of nonthermal electrons produced in small acceleration events in the solar corona. We use data from noise storm episodes observed jointly by the Giant Metrewave Radio Telescope (GMRT) and the Nancay Radioheliograph (NRH) to study characteristics of the nonthermal electrons involved in the emission. We find that the electrons carry 1021 to 1024 erg/s, and that the energy contained in the electrons producing a representative noise storm burst ranges from 1020 to 1023 ergs. These results are a direct probe of the energetics involved in ubiquitous, small-scale electron acceleration episodes in the corona, and could be relevant to a nanoflare-like scenario for coronal heating.

  9. Work on Planetary Atmospheres and Planetary Atmosphere Probes

    NASA Technical Reports Server (NTRS)

    Lester, Peter

    1999-01-01

    A summary final report of work accomplished is presented. Work was performed in the following areas: (1) Galileo Probe science analysis, (2) Galileo probe Atmosphere Structure Instrument, (3) Mars Pathfinder Atmosphere Structure/Meteorology instrument, (4) Mars Pathfinder data analysis, (5) Science Definition for future Mars missions, (6) Viking Lander data analysis, (7) winds in Mars atmosphere Venus atmospheric dynamics, (8) Pioneer Venus Probe data analysis, (9) Pioneer Venus anomaly analysis, (10) Discovery Venus Probe Titan probe instrument design, and (11) laboratory studies of Titan probe impact phenomena. The work has resulted in more than 10 articles published in archive journals, 2 encyclopedia articles, and many working papers. This final report is organized around the four planets on which there was activity, Jupiter, Mars, Venus, and Titan, with a closing section on Miscellaneous Activities. A major objective was to complete the fabrication, test, and evaluation of the atmosphere structure experiment on the Galileo probe, and to receive, analyze and interpret data received from the spacecraft. The instrument was launched on April 14, 1989. Calibration data were taken for all experiment sensors. The data were analyzed, fitted with algorithms, and summarized in a calibration report for use in analyzing and interpreting data returned from Jupiter's atmosphere. The sensors included were the primary science pressure, temperature and acceleration sensors, and the supporting engineering temperature sensors. Computer programs were written to decode the Experiment Data Record and convert the digital numbers to physical quantities, i.e., temperatures, pressures, and accelerations. The project office agreed to obtain telemetry of checkout data from the probe. Work to extend programs written for use on the Pioneer Venus project included: (1) massive heat shield ablation leading to important mass loss during entry; and (2) rapid planet rotation, which introduced

  10. DNA Probe Pooling for Rapid Delineation of Chromosomal Breakpoints

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

    Lu, Chun-Mei; Kwan, Johnson; Baumgartner, Adolf

    2009-01-30

    Structural chromosome aberrations are hallmarks of many human genetic diseases. The precise mapping of translocation breakpoints in tumors is important for identification of genes with altered levels of expression, prediction of tumor progression, therapy response, or length of disease-free survival as well as the preparation of probes for detection of tumor cells in peripheral blood. Similarly, in vitro fertilization (IVF) and preimplantation genetic diagnosis (PGD) for carriers of balanced, reciprocal translocations benefit from accurate breakpoint maps in the preparation of patient-specific DNA probes followed by a selection of normal or balanced oocytes or embryos. We expedited the process of breakpointmore » mapping and preparation of case-specific probes by utilizing physically mapped bacterial artificial chromosome (BAC) clones. Historically, breakpoint mapping is based on the definition of the smallest interval between proximal and distal probes. Thus, many of the DNA probes prepared for multi-clone and multi-color mapping experiments do not generate additional information. Our pooling protocol described here with examples from thyroid cancer research and PGD accelerates the delineation of translocation breakpoints without sacrificing resolution. The turnaround time from clone selection to mapping results using tumor or IVF patient samples can be as short as three to four days.« less

  11. Scale-by-scale contributions to Lagrangian particle acceleration

    NASA Astrophysics Data System (ADS)

    Lalescu, Cristian C.; Wilczek, Michael

    2017-11-01

    Fluctuations on a wide range of scales in both space and time are characteristic of turbulence. Lagrangian particles, advected by the flow, probe these fluctuations along their trajectories. In an effort to isolate the influence of the different scales on Lagrangian statistics, we employ direct numerical simulations (DNS) combined with a filtering approach. Specifically, we study the acceleration statistics of tracers advected in filtered fields to characterize the smallest temporal scales of the flow. Emphasis is put on the acceleration variance as a function of filter scale, along with the scaling properties of the relevant terms of the Navier-Stokes equations. We furthermore discuss scaling ranges for higher-order moments of the tracer acceleration, as well as the influence of the choice of filter on the results. Starting from the Lagrangian tracer acceleration as the short time limit of the Lagrangian velocity increment, we also quantify the influence of filtering on Lagrangian intermittency. Our work complements existing experimental results on intermittency and accelerations of finite-sized, neutrally-buoyant particles: for the passive tracers used in our DNS, feedback effects are neglected such that the spatial averaging effect is cleanly isolated.

  12. Chlorinated hydrocarbons in early life stages of the common snapping turtle (Chelydra serpentina serpentina) from a coastal wetland on Lake Ontario, Canada

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

    Bishop, C.A.; Lean, D.R.S.; Carey, J.H.

    1995-03-01

    To assess intra-clutch variation in contaminant concentrations in eggs, and to investigate the dynamics of chlorinated hydrocarbon accumulation in embryos of the common snapping turtle (Chelydra serpentina), concentrations of p,p{prime}-DDE, hexachlorobenzene, trans-nonachlor, cis-chlordane, and six PCB congeners were measured in eggs, embryos, and hatchlings. Samples were collected from Cootes Paradise, a wetland at the western end of Lake Ontario, Ontario, Canada. The intra-clutch variation in chlorinated hydrocarbon concentrations within four snapping turtle clutches was determined by analyzing the first, last, and middle five eggs oviposited in the nest. The first five eggs had the highest mean concentrations of all chlorinatedmore » hydrocarbons, wet weight, and egg diameter. On a lipid weight basis, the first five eggs contained the highest concentration of all compounds except total PCBs and cis-chlordane. The concentration of cis-chlordane was the only parameter measured that was significantly different among the three sets of eggs. At hatching, snapping turtles without yolk sacs contained from 55.2 to 90.5% of the absolute amount of organochlorine compounds measured in the egg at oviposition. Eighteen days after hatching, the body burden of PCBs and pesticides decreased to 45.3 to 62.2% of that in the fresh egg. The accumulation of organochlorine chemicals in embryonic turtles peaked at or just before hatching and then declined thereafter, which is consistent with trends reported in developing sea turtles, fish, and birds.« less

  13. Embryonic hypoxia programmes postprandial cardiovascular function in adult common snapping turtles (Chelydra serpentina).

    PubMed

    Wearing, Oliver H; Conner, Justin; Nelson, Derek; Crossley, Janna; Crossley, Dane A

    2017-07-15

    Reduced oxygen availability (hypoxia) is a potent stressor during embryonic development, altering the trajectory of trait maturation and organismal phenotype. We previously documented that chronic embryonic hypoxia has a lasting impact on the metabolic response to feeding in juvenile snapping turtles ( Chelydra serpentina ). Turtles exposed to hypoxia as embryos [10% O 2 (H10)] exhibited an earlier and increased peak postprandial oxygen consumption rate, compared with control turtles [21% O 2 (N21)]. In the current study, we measured central blood flow patterns to determine whether the elevated postprandial metabolic response in H10 turtles is linked to lasting impacts on convective transport. Five years after hatching, turtles were instrumented to quantify systemic ([Formula: see text]) and pulmonary ([Formula: see text]) blood flows and heart rate ( f H ) before and after a ∼5% body mass meal. In adult N21 and H10 turtles, f H was increased significantly by feeding. Although total stroke volume ( V S,tot ) remained at fasted values, this tachycardia contributed to an elevation in total cardiac output ([Formula: see text]). However, there was a postprandial reduction in a net left-right (L-R) shunt in N21 snapping turtles only. Relative to N21 turtles, H10 animals exhibited higher [Formula: see text] due to increased blood flow through the right systemic outflow vessels of the heart. This effect of hypoxic embryonic development, reducing a net L-R cardiac shunt, may support the increased postprandial metabolic rate we previously reported in H10 turtles, and is further demonstration of adult reptile cardiovascular physiology being programmed by embryonic hypoxia. © 2017. Published by The Company of Biologists Ltd.

  14. Snap Your Fingers! An ERP/sLORETA Study Investigating Implicit Processing of Self- vs. Other-Related Movement Sounds Using the Passive Oddball Paradigm

    PubMed Central

    Justen, Christoph; Herbert, Cornelia

    2016-01-01

    So far, neurophysiological studies have investigated implicit and explicit self-related processing particularly for self-related stimuli such as the own face or name. The present study extends previous research to the implicit processing of self-related movement sounds and explores their spatio-temporal dynamics. Event-related potentials (ERPs) were assessed while participants (N = 12 healthy subjects) listened passively to previously recorded self- and other-related finger snapping sounds, presented either as deviants or standards during an oddball paradigm. Passive listening to low (500 Hz) and high (1000 Hz) pure tones served as additional control. For self- vs. other-related finger snapping sounds, analysis of ERPs revealed significant differences in the time windows of the N2a/MMN and P3. An subsequent source localization analysis with standardized low-resolution brain electromagnetic tomography (sLORETA) revealed increased cortical activation in distinct motor areas such as the supplementary motor area (SMA) in the N2a/mismatch negativity (MMN) as well as the P3 time window during processing of self- and other-related finger snapping sounds. In contrast, brain regions associated with self-related processing [e.g., right anterior/posterior cingulate cortex (ACC/PPC)] as well as the right inferior parietal lobule (IPL) showed increased activation particularly during processing of self- vs. other-related finger snapping sounds in the time windows of the N2a/MMN (ACC/PCC) or the P3 (IPL). None of these brain regions showed enhanced activation while listening passively to low (500 Hz) and high (1000 Hz) pure tones. Taken together, the current results indicate (1) a specific role of motor regions such as SMA during auditory processing of movement-related information, regardless of whether this information is self- or other-related, (2) activation of neural sources such as the ACC/PCC and the IPL during implicit processing of self-related movement stimuli, and (3

  15. NASA Snaps Nighttime View of Massive Iceberg Split

    NASA Image and Video Library

    2017-07-25

    As Antarctica remains shrouded in darkness during the Southern Hemisphere winter, the Thermal Infrared Sensor (TIRS) on Landsat 8 captured a new snap of the 2,240-square-mile iceberg that split off from the Antarctic Peninsula’s Larsen C ice shelf on July 10-12. The satellite imagery is a composite of Landsat 8 as it past on July 14 and July 21 and shows that the main berg, A-68, has already lost several smaller pieces. The A-68 iceberg is being carried by currents northward out of its embayment on the Larsen C ice shelf. The latest imagery also details a group of three small, not yet released icebergs at the north end of the embayment. Credits: NASA Goddard/UMBC JCET, Christopher A. Shuman NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

  16. Review of Gravity Probe B

    NASA Technical Reports Server (NTRS)

    1995-01-01

    In response to a request by the NASA Administrator, the National Research Council (NRC) has conducted an accelerated scientific review of NASA's Gravity Probe B (GP-B) mission. The review was carried out by the Task Group on Gravity Probe B, under the auspices of the NRC's Space Studies Board and Board on Physics and Astronomy. The specific charge to the task group was to review the GP-B mission with respect to the following terms of reference: (1) scientific importance - including a current assessment of the value of the project in the context of recent progress in gravitational physics and relevant technology; (2) technical feasibility - the technical approach will be evaluated for likelihood of success, both in terms of achievement of flight mission objectives but also in terms of scientific conclusiveness of the various possible outcomes for the measurements to be made; and (3) competitive value - if possible, GP-B science will be assessed qualitatively against the objectives and accomplishments of one or more fundamental physics projects of similar cost (e.g., the Cosmic Background Explorer, COBE).

  17. Effects of environmentally relevant concentrations of atrazine on gonadal development of snapping turtles (Chelydra serpentina).

    PubMed

    de Solla, Shane R; Martin, Pamela A; Fernie, Kimberly J; Park, Brad J; Mayne, Gregory

    2006-02-01

    The herbicide atrazine has been suspected of affecting sexual development by inducing aromatase, resulting in the increased conversion of androgens to estrogens. We used snapping turtles (Chelydra serpentina), a species in which sex is dependent on the production of estrogen through aromatase activity in a temperature-dependent manner, to investigate if environmentally relevant exposures to atrazine affected gonadal development. Eggs were incubated in soil to which atrazine was applied at a typical field application rate (3.1 L/ha), 10-fold this rate (31 L/ha), and a control rate (no atrazine) for the duration of embryonic development. The incubation temperature (25 degrees C) was selected to produce only males. Although some males with testicular oocytes and females were produced in the atrazine-treated groups (3.3-3.7%) but not in the control group, no statistical differences were found among treatments. Furthermore, snapping turtle eggs collected from natural nests in a corn field were incubated at the pivotal temperature (27.5 degrees C) at which both males and females normally would be produced, and some males had oocytes in the testes (15.4%). The presence of low numbers of males with oocytes may be a natural phenomenon, and we have limited evidence to suggest that the presence of normal males with oocytes may represent a feminizing effect of atrazine. Histological examination of the thyroid gland revealed no effect on thyroid morphology.

  18. Wavefront-sensor-based electron density measurements for laser-plasma accelerators.

    PubMed

    Plateau, G R; Matlis, N H; Geddes, C G R; Gonsalves, A J; Shiraishi, S; Lin, C; van Mourik, R A; Leemans, W P

    2010-03-01

    Characterization of the electron density in laser produced plasmas is presented using direct wavefront analysis of a probe laser beam. The performance of a laser-driven plasma-wakefield accelerator depends on the plasma wavelength and hence on the electron density. Density measurements using a conventional folded-wave interferometer and using a commercial wavefront sensor are compared for different regimes of the laser-plasma accelerator. It is shown that direct wavefront measurements agree with interferometric measurements and, because of the robustness of the compact commercial device, offer greater phase sensitivity and straightforward analysis, improving shot-to-shot plasma density diagnostics.

  19. Wavefront-sensor-based electron density measurements for laser-plasma accelerators

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

    Plateau, Guillaume; Matlis, Nicholas; Geddes, Cameron

    2010-02-20

    Characterization of the electron density in laser produced plasmas is presented using direct wavefront analysis of a probe laser beam. The performance of a laser-driven plasma-wakefield accelerator depends on the plasma wavelength, hence on the electron density. Density measurements using a conventional folded-wave interferometer and using a commercial wavefront sensor are compared for different regimes of the laser-plasma accelerator. It is shown that direct wavefront measurements agree with interferometric measurements and, because of the robustness of the compact commercial device, have greater phase sensitivity, straightforward analysis, improving shot-to-shot plasma-density diagnostics.

  20. Cyclotron Acceleration of Relativistic Electrons through Landau Resonance with Obliquely Propagating Whistler Mode Chorus Emissions

    NASA Astrophysics Data System (ADS)

    Omura, Y.; Hsieh, Y. K.; Foster, J. C.; Erickson, P. J.; Kletzing, C.; Baker, D. N.

    2017-12-01

    A recent test particle simulation of obliquely propagating whistler mode wave-particle interaction [Hsieh and Omura, 2017] shows that the perpendicular wave electric field can play a significant role in trapping and accelerating relativistic electrons through Landau resonance. A further theoretical and numerical investigation verifies that there occurs nonlinear wave trapping of relativistic electrons by the nonlinear Lorentz force of the perpendicular wave magnetic field. An electron moving with a parallel velocity equal to the parallel phase velocity of an obliquely propagating wave basically see a stationary wave phase. Since the electron position is displaced from its gyrocenter by a distance ρ*sin(φ), where ρ is the gyroradius and φ is the gyrophase, the wave phase is modulated with the gyromotion, and the stationary wave fields as seen by the electron are expanded as series of Bessel functions Jn with phase variations n*φ. The J1 components of the wave electric and magnetic fields rotate in the right-hand direction with the gyrofrequency, and they can be in resonance with the electron undergoing the gyromotion, resulting in effective electron acceleration and pitch angle scattering. We have performed a subpacket analysis of chorus waveforms observed by the Van Allen Probes [Foster et al., 2017], and calculated the energy gain by the cyclotron acceleration through Landau resonance. We compare the efficiencies of accelerations by cyclotron and Landau resonances in typical events of rapid electron acceleration observed by the Van Allen Probes.References:[1] Hsieh, Y.-K., and Y. Omura (2017), Nonlinear dynamics of electrons interacting with oblique whistler mode chorus in the magnetosphere, J. Geophys. Res. Space Physics, 122, 675-694, doi:10.1002/2016JA023255.[2] Foster, J. C., P. J. Erickson, Y. Omura, D. N. Baker, C. A. Kletzing, and S. G. Claudepierre (2017), Van Allen Probes observations of prompt MeV radiation belt electron acceleration in nonlinear

  1. Field assessment of a snap bean ozone bioindicator system under elevated ozone and carbon dioxide in a free air system

    USDA-ARS?s Scientific Manuscript database

    Ozone-sensitive (S156) and -tolerant (R123 and R331) genotypes of snap bean (Phaseolus vulgaris L.) were tested as a plant bioindicator system for detecting O3 effects at current and future levels of tropospheric O3 and atmospheric CO2 under field conditions. Plants were exposed to reciprocal combi...

  2. Linear servomotor probe drive system with real-time self-adaptive position control for the Alcator C-Mod tokamak

    NASA Astrophysics Data System (ADS)

    Brunner, D.; Kuang, A. Q.; LaBombard, B.; Burke, W.

    2017-07-01

    A new servomotor drive system has been developed for the horizontal reciprocating probe on the Alcator C-Mod tokamak. Real-time measurements of plasma temperature and density—through use of a mirror Langmuir probe bias system—combined with a commercial linear servomotor and controller enable self-adaptive position control. Probe surface temperature and its rate of change are computed in real time and used to control probe insertion depth. It is found that a universal trigger threshold can be defined in terms of these two parameters; if the probe is triggered to retract when crossing the trigger threshold, it will reach the same ultimate surface temperature, independent of velocity, acceleration, or scrape-off layer heat flux scale length. In addition to controlling the probe motion, the controller is used to monitor and control all aspects of the integrated probe drive system.

  3. Application and further characterization of the snap bean S156/R123 ozone biomonitoring system in relation to ambient air temperature

    USDA-ARS?s Scientific Manuscript database

    Increased mixing ratios of ground-level ozone threaten individual plants, plant communities and ecosystems. In this sense, ozone biomonitoring is of great interest. The ozone-sensitive S156 and the ozone-tolerant R123 genotypes of snap bean (Phaseolus vulgaris L.) have been proposed as a potential t...

  4. 75 FR 21050 - V-GPO, Inc., Valesc Holdings, Inc., Venture Stores, Inc., Vertigo Theme Parks, Inc. (f/k/a Snap2...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-22

    ... SECURITIES AND EXCHANGE COMMISSION [File No. 500-1] V-GPO, Inc., Valesc Holdings, Inc., Venture Stores, Inc., Vertigo Theme Parks, Inc. (f/k/a Snap2 Corp.), Videolan Technologies, Inc., VisionGateway... Commission that there is a lack of current and accurate information concerning the securities of Vertigo...

  5. SNAP23-Dependent Surface Translocation of Leukotriene B4 (LTB4) Receptor 1 Is Essential for NOX2-Mediated Exocytotic Degranulation in Human Mast Cells Induced by Trichomonas vaginalis-Secreted LTB4

    PubMed Central

    Lee, Young Ah; Kim, Kyeong Ah; El-Benna, Jamel

    2016-01-01

    ABSTRACT Trichomonas vaginalis is a sexually transmitted parasite that causes vaginitis in women and itself secretes lipid mediator leukotriene B4 (LTB4). Mast cells are important effector cells of tissue inflammation during infection with parasites. Membrane-bridging SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptor) complexes are critical for fusion during exocytosis. Although T. vaginalis-derived secretory products (TvSP) have been shown to induce exocytosis in mast cells, information regarding the signaling mechanisms between mast cell activation and TvSP is limited. In this study, we found that SNAP23-dependent surface trafficking of LTB4 receptor 1 (BLT1) is required for nicotinamide adenine dinucleotide phosphate oxidase 2 (NOX2)-mediated exocytotic degranulation of mast cells induced by TvSP. First, stimulation with TvSP induced exocytotic degranulation and reactive oxygen species (ROS) generation in HMC-1 cells. Next, TvSP-induced ROS generation and exocytosis were strongly inhibited by transfection of BLT1 small interfering RNA (siRNA). TvSP induced trafficking of BLT1 from the cytosol to the plasma membrane. We also found that knockdown of SNAP23 abrogated TvSP-induced ROS generation, exocytosis, and surface trafficking of BLT1 in HMC-1 cells. By coimmunoprecipitation, there was a physical interaction between BLT1 and SNAP23 in TvSP-stimulated HMC-1 cells. Taken together, our results suggest that SNAP23-dependent surface trafficking of BLT1 is essential for exocytosis in human mast cells induced by T. vaginalis-secreted LTB4. Our data collectively demonstrate a novel regulatory mechanism for SNAP23-dependent mast cell activation of T. vaginalis-secreted LTB4 involving surface trafficking of BLT1. These results can help to explain how the cross talk mechanism between parasite and host can govern deliberately tissue inflammatory responses. PMID:27795355

  6. SNAP23-Dependent Surface Translocation of Leukotriene B4 (LTB4) Receptor 1 Is Essential for NOX2-Mediated Exocytotic Degranulation in Human Mast Cells Induced by Trichomonas vaginalis-Secreted LTB4.

    PubMed

    Min, Arim; Lee, Young Ah; Kim, Kyeong Ah; El-Benna, Jamel; Shin, Myeong Heon

    2017-01-01

    Trichomonas vaginalis is a sexually transmitted parasite that causes vaginitis in women and itself secretes lipid mediator leukotriene B 4 (LTB 4 ). Mast cells are important effector cells of tissue inflammation during infection with parasites. Membrane-bridging SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptor) complexes are critical for fusion during exocytosis. Although T. vaginalis-derived secretory products (TvSP) have been shown to induce exocytosis in mast cells, information regarding the signaling mechanisms between mast cell activation and TvSP is limited. In this study, we found that SNAP23-dependent surface trafficking of LTB 4 receptor 1 (BLT1) is required for nicotinamide adenine dinucleotide phosphate oxidase 2 (NOX2)-mediated exocytotic degranulation of mast cells induced by TvSP. First, stimulation with TvSP induced exocytotic degranulation and reactive oxygen species (ROS) generation in HMC-1 cells. Next, TvSP-induced ROS generation and exocytosis were strongly inhibited by transfection of BLT1 small interfering RNA (siRNA). TvSP induced trafficking of BLT1 from the cytosol to the plasma membrane. We also found that knockdown of SNAP23 abrogated TvSP-induced ROS generation, exocytosis, and surface trafficking of BLT1 in HMC-1 cells. By coimmunoprecipitation, there was a physical interaction between BLT1 and SNAP23 in TvSP-stimulated HMC-1 cells. Taken together, our results suggest that SNAP23-dependent surface trafficking of BLT1 is essential for exocytosis in human mast cells induced by T. vaginalis-secreted LTB 4 Our data collectively demonstrate a novel regulatory mechanism for SNAP23-dependent mast cell activation of T. vaginalis-secreted LTB 4 involving surface trafficking of BLT1. These results can help to explain how the cross talk mechanism between parasite and host can govern deliberately tissue inflammatory responses. Copyright © 2016 American Society for Microbiology.

  7. Particle Acceleration at the Sun and in the Heliosphere

    NASA Technical Reports Server (NTRS)

    Reames, Donald V.

    1999-01-01

    Energetic particles are accelerated in rich profusion at sites throughout the heliosphere. They come from solar flares in the low corona, from shock waves driven outward by coronal mass ejections (CMEs), from planetary magnetospheres and bow shocks. They come from corotating interaction regions (CIRs) produced by high-speed streams in the solar wind, and from the heliospheric termination shock at the outer edge of the heliospheric cavity. We sample all these populations near Earth, but can distinguish them readily by their element and isotope abundances, ionization states, energy spectra, angular distributions and time behavior. Remote spacecraft have probed the spatial distributions of the particles and examined new sources in situ. Most acceleration sources can be "seen" only by direct observation of the particles; few photons are produced at these sites. Wave-particle interactions are an essential feature in acceleration sources and, for shock acceleration, new evidence of energetic-proton-generated waves has come from abundance variations and from local cross-field scattering. Element abundances often tell us the physics the source plasma itself, prior to acceleration. By comparing different populations, we learn more about the sources, and about the physics of acceleration and transport, than we can possibly learn from one source alone.

  8. Mercury ion thruster research, 1977. [plasma acceleration

    NASA Technical Reports Server (NTRS)

    Wilbur, P. J.

    1977-01-01

    The measured ion beam divergence characteristics of two and three-grid, multiaperture accelerator systems are presented. The effects of perveance, geometry, net-to-total accelerating voltage, discharge voltage and propellant are examined. The applicability of a model describing doubly-charged ion densities in mercury thrusters is demonstrated for an 8-cm diameter thruster. The results of detailed Langmuir probing of the interior of an operating cathode are given and used to determine the ionization fraction as a function of position upstream of the cathode orifice. A mathematical model of discharge chamber electron diffusion and collection processes is presented along with scaling laws useful in estimating performance of large diameter and/or high specific impluse thrusters. A model describing the production of ionized molecular nitrogen in ion thrusters is included.

  9. Growth of Cosmic Structure: Probing Dark Energy Beyond Expansion

    DOE PAGES

    Huterer, Dragan; Kirkby, David; Bean, Rachel; ...

    2014-03-15

    The quantity and quality of cosmic structure observations have greatly accelerated in recent years, and further leaps forward will be facilitated by imminent projects. These will enable us to map the evolution of dark and baryonic matter density fluctuations over cosmic history. The way that these fluctuations vary over space and time is sensitive to several pieces of fundamental physics: the primordial perturbations generated by GUT-scale physics; neutrino masses and interactions; the nature of dark matter and dark energy. We focus on the last of these here: the ways that combining probes of growth with those of the cosmic expansionmore » such as distance-redshift relations will pin down the mechanism driving the acceleration of the Universe.« less

  10. Growth of Cosmic Structure: Probing Dark Energy Beyond Expansion

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

    Huterer, Dragan; Kirkby, David; Bean, Rachel

    The quantity and quality of cosmic structure observations have greatly accelerated in recent years, and further leaps forward will be facilitated by imminent projects. These will enable us to map the evolution of dark and baryonic matter density fluctuations over cosmic history. The way that these fluctuations vary over space and time is sensitive to several pieces of fundamental physics: the primordial perturbations generated by GUT-scale physics; neutrino masses and interactions; the nature of dark matter and dark energy. We focus on the last of these here: the ways that combining probes of growth with those of the cosmic expansionmore » such as distance-redshift relations will pin down the mechanism driving the acceleration of the Universe.« less

  11. Refractory clad transient internal probe for magnetic field measurements in high temperature plasmas

    NASA Astrophysics Data System (ADS)

    Kim, Hyundae; Cellamare, Vincent; Jarboe, Thomas R.; Mattick, Arthur T.

    2005-05-01

    The transient internal probe (TIP) is a diagnostic for local internal field measurements in high temperature plasmas. A verdet material, which rotates the polarization angle of the laser light under magnetic fields, is launched into a plasma at about 1.8km/s. A linearly polarized Ar+ laser illuminates the probe in transit and the light retroreflected from the probe is analyzed to determine the local magnetic field profiles. The TIP has been used for magnetic field measurements on the helicity injected torus where electron temperature Te⩽80eV. In order to apply the TIP in higher temperature plasmas, refractory clad probes have been developed utilizing a sapphire tube, rear disc, and a MgO window on the front. The high melting points of these refractory materials should allow probe operation at plasma electron temperatures up to Te˜300eV. A retroreflecting probe has also been developed using "catseye" optics. The front window is replaced with a plano-convex MgO lens, and the back surface of the probe is aluminized. This approach reduces spurious polarization effects and provides refractory cladding for the probe entrance face. In-flight measurements of a static magnetic field demonstrate the ability of the clad probes to withstand gun-launch acceleration, and provide high accuracy measurements of magnetic field.

  12. Clinical and cognitive trajectories in cognitively healthy elderly individuals with suspected non-Alzheimer's disease pathophysiology (SNAP) or Alzheimer's disease pathology: a longitudinal study.

    PubMed

    Burnham, Samantha C; Bourgeat, Pierrick; Doré, Vincent; Savage, Greg; Brown, Belinda; Laws, Simon; Maruff, Paul; Salvado, Olivier; Ames, David; Martins, Ralph N; Masters, Colin L; Rowe, Christopher C; Villemagne, Victor L

    2016-09-01

    Brain amyloid β (Aβ) deposition and neurodegeneration have been documented in about 50-60% of cognitively healthy elderly individuals (aged 60 years or older). The long-term cognitive consequences of the presence of Alzheimer's disease pathology and neurodegeneration, and whether they have an independent or synergistic effect on cognition, are unclear. We aimed to characterise the long-term clinical and cognitive trajectories of healthy elderly individuals using a two-marker (Alzheimer's disease pathology and neurodegeneration) imaging construct. Between Nov 3, 2006, and Nov 25, 2014, 573 cognitively healthy individuals in Melbourne and Perth, Australia, (mean age 73·1 years [SD 6·2]; 58% women) were enrolled in the Australian Imaging, Biomarker and Lifestyle (AIBL) study. Alzheimer's disease pathology (A) was determined by measuring Aβ deposition by PET, and neurodegeneration (N) was established by measuring hippocampal volume using MRI. Individuals were categorised as A(-)N(-), A(+)N(-), A(+)N(+), or suspected non-Alzheimer's disease pathophysiology (A(-)N(+), SNAP). Clinical progression, hippocampal volume, standard neuropsychological tests, and domain-specific and global cognitive composite scores were assessed over 6 years of follow-up. Linear mixed effect models and a Cox proportional hazards model of survival were used to evaluate, compare, and contrast the clinical, cognitive, and volumetric trajectories of patients in the four AN categories. 50 (9%) healthy individuals were classified as A(+)N(+), 87 (15%) as A(+)N(-), 310 (54%) as A(-)N(-), and 126 (22%) as SNAP. APOE ε4 was more frequent in participants in the A(+)N(+) (27; 54%) and A(+)N(-) (42; 48%) groups than in the A(-)N(-) (66; 21%) and SNAP groups (23; 18%). The A(+)N(-) and A(+)N(+) groups had significantly faster cognitive decline than the A(-)N(-) group (0·08 SD per year for AIBL-Preclinical AD Cognitive Composite [PACC]; p<0·0001; and 0·25; p<0·0001; respectively). The A (+)N

  13. Electron acceleration behind a wavy dipolarization front

    NASA Astrophysics Data System (ADS)

    Wu, Mingyu; Lu, Quanming; Volwerk, Martin; Nakamura, Rumi; Zhang, Tielong

    2018-02-01

    In this paper, with the in-situ observations from the Time History of Events and Macroscale Interactions during Substorms (THEMIS) probes we report a wavy dipolarization front (DF) event, where the DF has different magnetic structures and electron distributions at different y positions in the Geocentric Solar Magnetospheric (GSM) coordinates. At y ˜2.1RE (RE is the radius of Earth), the DF has a relatively simple structure, which is similar to that of a conventional DF. At y ˜3.0RE, the DF is revealed to have a multiple DF structure, where the plasma exhibits a vortex flow. Such a wavy DF could be the results of the interchange instability. The different structure of such a wavy DF at different sites has a great effect on electron acceleration. Fermi acceleration can occur at the site of the DF with a simple or multiple DF structure, while betatron acceleration as a local process has the contribution to energetic electrons only at the site of the DF with a simple structure.

  14. Solar wind conditions leading to efficient radiation belt electron acceleration: A superposed epoch analysis

    DOE PAGES

    Li, W.; Thorne, R. M.; Bortnik, J.; ...

    2015-09-07

    In this study by determining preferential solar wind conditions leading to efficient radiation belt electron acceleration is crucial for predicting radiation belt electron dynamics. Using Van Allen Probes electron observations (>1 MeV) from 2012 to 2015, we identify a number of efficient and inefficient acceleration events separately to perform a superposed epoch analysis of the corresponding solar wind parameters and geomagnetic indices. By directly comparing efficient and inefficient acceleration events, we clearly show that prolonged southward Bz, high solar wind speed, and low dynamic pressure are critical for electron acceleration to >1 MeV energies in the heart of the outermore » radiation belt. We also evaluate chorus wave evolution using the superposed epoch analysis for the identified efficient and inefficient acceleration events and find that chorus wave intensity is much stronger and lasts longer during efficient electron acceleration events, supporting the scenario that chorus waves play a key role in MeV electron acceleration.« less

  15. Effects of ethylenediurea on snap bean at a range of ozone concentrations

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

    Miller, J.E.; Pursley, W.A.; Heagle, A.S.

    Ethylenediurea (EDU) [N-[2-(2-Oxo-1-imidazolidinyl) ethyl]-N{prime}-phenylurea] often protects plants from visible foliar injury due ozone{sub 3}. A few studies have indicated that EDU can suppress plant growth and yield. Because of the potential value of EDU as a research and assessment tool, controlled field experiments with snap bean Phaseolus vulgaris L. ({open_quotes}BBL-290{close_quotes}) were performed to test the effectiveness of different EDU application rates used in open-top chambers in each of two experiments [charcoal-filtered (CF) air, nonfiltered (NF) air, and nominal O{sub 3} additions of 0.025 and 0.05 or 0.03 and 0.06 {mu}LL{sup -1}O{sub 3} to NF air]. Ethylenediurea was added biweekly tomore » the potting medium . The EDU treatment concentration were 0, 14, 28, 56, and 120 and 0, 8, 16, and 32 mg EDU (active) L{sup -1} of potting medium in experiments one and two, respectively. Ethylenediurea provided some protection against O{sub 3}-induced foliar injury and growth suppression in both experiments. Measurements of net carbon exchange rate (NCER) and carbohydrate status of the tissues reflected the protective effects of EDU. In the first experiment EDU caused visible foliar injury at some growth stages and suppressed growth. In the second experiment, visible foliar injury was not caused by EDU at any concentration, but pod biomass (yield) was suppressed by EDU in CF chambers. The differences may have been due to environmental conditions (i.e., hot and dry during the first experiment and cooler during the second). Ethylenediurea also affected biomass partitioning in the plants grown in CF air (relative biomass was increased in leaves and decreased in pods). The results indicate that although EDU does protect or partially protect snap bean against O{sub 3} injury, it may also affect physiology and growth. 27 refs., 6 tabs.« less

  16. Magnetohydrodynamic modeling of three Van Allen Probes storms in 2012 and 2013

    NASA Astrophysics Data System (ADS)

    Paral, J.; Hudson, M. K.; Kress, B. T.; Wiltberger, M. J.; Wygant, J. R.; Singer, H. J.

    2015-08-01

    Coronal mass ejection (CME)-shock compression of the dayside magnetopause has been observed to cause both prompt enhancement of radiation belt electron flux due to inward radial transport of electrons conserving their first adiabatic invariant and prompt losses which at times entirely eliminate the outer zone. Recent numerical studies suggest that enhanced ultra-low frequency (ULF) wave activity is necessary to explain electron losses deeper inside the magnetosphere than magnetopause incursion following CME-shock arrival. A combination of radial transport and magnetopause shadowing can account for losses observed at radial distances into L = 4.5, well within the computed magnetopause location. We compare ULF wave power from the Electric Field and Waves (EFW) electric field instrument on the Van Allen Probes for the 8 October 2013 storm with ULF wave power simulated using the Lyon-Fedder-Mobarry (LFM) global magnetohydrodynamic (MHD) magnetospheric simulation code coupled to the Rice Convection Model (RCM). Two other storms with strong magnetopause compression, 8-9 October 2012 and 17-18 March 2013, are also examined. We show that the global MHD model captures the azimuthal magnetosonic impulse propagation speed and amplitude observed by the Van Allen Probes which is responsible for prompt acceleration at MeV energies reported for the 8 October 2013 storm. The simulation also captures the ULF wave power in the azimuthal component of the electric field, responsible for acceleration and radial transport of electrons, at frequencies comparable to the electron drift period. This electric field impulse has been shown to explain observations in related studies (Foster et al., 2015) of electron acceleration and drift phase bunching by the Energetic Particle, Composition, and Thermal Plasma Suite (ECT) instrument on the Van Allen Probes.

  17. EFFECTS OF SIMULATED ACIDIC RAIN APPLIED ALONE AND IN COMBINATION WITH AMBIENT RAIN ON GROWTH AND YIELD OF FIELD-GROWN SNAP BEAN

    EPA Science Inventory

    Field-grown snap bean plants were treated with simulated acidic rain applied either alone or in combination with ambient rain and the effects on growth and yield were determined. In plots where ambient rain was excluded, a retractable canopy was activated to shield the crop. Four...

  18. Constraints on the extremely high-energy cosmic ray accelerators from classical electrodynamics

    NASA Astrophysics Data System (ADS)

    Aharonian, F. A.; Belyanin, A. A.; Derishev, E. V.; Kocharovsky, V. V.; Kocharovsky, Vl. V.

    2002-07-01

    We formulate the general requirements, set by classical electrodynamics, on the sources of extremely high-energy cosmic rays (EHECRs). It is shown that the parameters of EHECR accelerators are strongly limited not only by the particle confinement in large-scale magnetic fields or by the difference in electric potentials (generalized Hillas criterion) but also by the synchrotron radiation, the electro-bremsstrahlung, or the curvature radiation of accelerated particles. Optimization of these requirements in terms of an accelerator's size and magnetic field strength results in the ultimate lower limit to the overall source energy budget, which scales as the fifth power of attainable particle energy. Hard γ rays accompanying generation of EHECRs can be used to probe potential acceleration sites. We apply the results to several populations of astrophysical objects-potential EHECR sources-and discuss their ability to accelerate protons to 1020 eV and beyond. The possibility of gain from ultrarelativistic bulk flows is addressed, with active galactic nuclei and gamma-ray bursts being the examples.

  19. Constraints on the extremely high-energy cosmic rays accelerators from classical electrodynamics

    NASA Astrophysics Data System (ADS)

    Belyanin, A.; Aharonian, F.; Derishev, E.; Kocharovsky, V.; Kocharovsky, V.

    We formulate the general requirements, set by classical electrodynamics, to the sources of extremely high-energy cosmic rays (EHECRs). It is shown that the parameters of EHECR accelerators are strongly limited not only by the particle confinement in large-scale magnetic field or by the difference in electric potentials (generalized Hillas criterion), but also by the synchrotron radiation, the electro-bremsstrahlung, or the curvature radiation of accelerated particles. Optimization of these requirements in terms of accelerator's size and magnetic field strength results in the ultimate lower limit to the overall source energy budget, which scales as the fifth power of attainable particle energy. Hard gamma-rays accompanying generation of EHECRs can be used to probe potential acceleration sites. We apply the results to several populations of astrophysical objects - potential EHECR sources - and discuss their ability to accelerate protons to 1020 eV and beyond. A possibility to gain from ultrarelativistic bulk flows is addressed, with Active Galactic Nuclei and Gamma-Ray Bursts being the examples.

  20. Helminth infracommunities of the common snapping turtle (Chelydra serpentina serpentina) from Westhampton Lake, Virginia.

    PubMed

    Zelmer, Derek A; Platt, Thomas R

    2009-12-01

    Patterns of infracommunity similarity were examined for 27 male and 6 female common snapping turtles, Chelydra serpentina serpentina, collected from Westhampton Lake on the campus of the University of Richmond in Richmond, Virginia, during the summer months of 1979 and 1980. Patterns of infracommunity similarity based on parasite abundance emphasized differences between years and between host sexes. Patterns of similarity based on parasite presence or absence emphasized differences among the months sampled. This suggests that there were consistent seasonal changes across both years in terms of which parasites were present, but that there were differences between years in terms of the abundances of those parasites.

  1. Ponderomotive electron acceleration in a silicon-based nanoplasmonic waveguide.

    PubMed

    Sederberg, S; Elezzabi, A Y

    2014-10-17

    Ponderomotive electron acceleration is demonstrated in a semiconductor-loaded nanoplasmonic waveguide. Photogenerated free carriers are accelerated by the tightly confined nanoplasmonic fields and reach energies exceeding the threshold for impact ionization. Broadband (375 nm ≤ λ ≤ 650  nm) white light emission is observed from the nanoplasmonic waveguides. Exponential growth of visible light emission confirms the exponential growth of the electron population, demonstrating the presence of an optical-field-driven electron avalanche. Electron sweeping dynamics are visualized using pump-probe measurements, and a sweeping time of 1.98 ± 0.40 ps is measured. These findings offer a means to harness the potential of the emerging field of ultrafast nonlinear nanoplasmonics.

  2. Sugar-snap cookie dough setting: the impact of sucrose on gluten functionality.

    PubMed

    Pareyt, Bram; Brijs, Kristof; Delcour, Jan A

    2009-09-09

    In sugar-snap cookie making, sucrose influences the physicochemical transformations of the flour components and is responsible for both cookie sweetness and texture. Sucrose, together with low moisture levels, raises the starch gelatinization temperature to such an extent that little if any of it gelatinizes during baking. However, there is no agreement on the effects that it has on gluten during cookie making. The present study revealed that increasing sucrose levels in the recipe increasingly delay or inhibit gluten cross-linking, as judged from the loss of sodium dodecyl sulfate-extractable protein. This causes cookies containing higher sucrose levels to set later and to have a larger diameter. Gluten entanglement and/or cross-linking result in resistance to collapse, at the same time, cause setting during baking and, hence, determine cookie diameter.

  3. 46 CFR 160.060-3a - Materials-Dee ring and snap hook assemblies and other instruments of closure for buoyant vests.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... instruments of closure for buoyant vests. 160.060-3a Section 160.060-3a Shipping COAST GUARD, DEPARTMENT OF... LIFESAVING EQUIPMENT Specification for a Buoyant Vest, Unicellular Polyethylene Foam, Adult and Child § 160.060-3a Materials—Dee ring and snap hook assemblies and other instruments of closure for buoyant vests...

  4. 46 CFR 160.060-3a - Materials-Dee ring and snap hook assemblies and other instruments of closure for buoyant vests.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... instruments of closure for buoyant vests. 160.060-3a Section 160.060-3a Shipping COAST GUARD, DEPARTMENT OF... LIFESAVING EQUIPMENT Specification for a Buoyant Vest, Unicellular Polyethylene Foam, Adult and Child § 160.060-3a Materials—Dee ring and snap hook assemblies and other instruments of closure for buoyant vests...

  5. 46 CFR 160.060-3a - Materials-Dee ring and snap hook assemblies and other instruments of closure for buoyant vests.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... instruments of closure for buoyant vests. 160.060-3a Section 160.060-3a Shipping COAST GUARD, DEPARTMENT OF... LIFESAVING EQUIPMENT Specification for a Buoyant Vest, Unicellular Polyethylene Foam, Adult and Child § 160.060-3a Materials—Dee ring and snap hook assemblies and other instruments of closure for buoyant vests...

  6. 46 CFR 160.060-3a - Materials-Dee ring and snap hook assemblies and other instruments of closure for buoyant vests.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... instruments of closure for buoyant vests. 160.060-3a Section 160.060-3a Shipping COAST GUARD, DEPARTMENT OF... LIFESAVING EQUIPMENT Specification for a Buoyant Vest, Unicellular Polyethylene Foam, Adult and Child § 160.060-3a Materials—Dee ring and snap hook assemblies and other instruments of closure for buoyant vests...

  7. Atrazine alters expression of reproductive and stress genes in the developing hypothalamus of the snapping turtle, Chelydra serpentina.

    PubMed

    Russart, Kathryn L G; Rhen, Turk

    2016-07-29

    Atrazine is an herbicide used to control broadleaf grasses and a suspected endocrine disrupting chemical. Snapping turtles lay eggs between late May and early June, which could lead to atrazine exposure via field runoff. Our goal was to determine whether a single exposure to 2ppb or 40ppb atrazine during embryogenesis could induce short- and long-term changes in gene expression within the hypothalamus of snapping turtles. We treated eggs with atrazine following sex determination and measured gene expression within the hypothalamus. We selected genes a priori for their role in the hypothalamus-pituitary-gonad or the hypothalamus-pituitary-adrenal axes of the endocrine system. We did not identify any changes in gene expression 24-h after treatment. However, at hatching AR, Kiss1R, and POMC expression was upregulated in both sexes, while expression of CYP19A1 and PDYN was increased in females. Six months after hatching, CYP19A1 and PRLH expression was increased in animals treated with 2ppb atrazine. Our study shows persistent changes in hypothalamic gene expression due to low-dose embryonic exposure to the herbicide atrazine with significant effects in both the HPG and HPA axes. Effects reported here appear to be conserved among vertebrates. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  8. Compact Torus Acceleration and Injection Experiment

    NASA Astrophysics Data System (ADS)

    Fukumoto, Naoyuki; Fujiwara, Makoto; Nagata, Masayoshi; Uyama, Tadao; Oda, Yasushi; Azuma, Kingo

    1996-11-01

    The spheromak-type compact torus (CT) acceleration and injection experiment has been carried out using the Himeji Institute of Technology Compact Torus Injector (HIT-CTI). We explore the possibility of refueling, density control, current drive, and edge electric field control of tokamak plasma by means of CT injection. In last September the new HIT-CTI was built up to achieve higher speed (Vct>200 km/s) and higher density CT plasmoid by improving the capacitor bank system and eliminating the impurity and neutral particles. At initial formation discharge tests the gun for formation and compression successfully produced a CT plasmoid and injected it between electrodes for acceleration. (Initial velocity Vct.ini. 32 km/s, Bct 1 kG, Rct=5.5 cm). The formation capacitor bank will be upgraded to two 36 mF capacitors operating at 20 kV (14.4 kJ). The acceleration capacitor bank will be also upgraded to two 36 mF capacitors operating at 20 kV (14.4 kJ). The HIT-CTI will be optimized to obtain suitable CT parameters after acceleration (Bct>5 kG, Lct 20 cm, Vct>200 km/s). In the respect of CT parameter measurement magnetic probes and a He-Ne laser interferometer will be employed in order to measure the CT magnetic field, velocity, density, and length. CT acceleration experimental data on the HIT-CTI and the plan of CT injection experiment on the JFT-2M tokamak (JAERI) will be presented at the meeting.

  9. Flour mill stream blending affects sugar snap cookie and Japanese sponge cake quality and oxidative cross-linking potential of soft white wheat.

    USDA-ARS?s Scientific Manuscript database

    The purpose of this research was to study the functional differences between straight grade (75% extraction rate) and patent (60% extraction rate) flour blends from 28 genetically pure soft white and club wheat grain lots, as evidenced by variation in sugar snap cookie and Japanese sponge cake quali...

  10. Interstellar Mapping and Acceleration Probe (IMAP)

    NASA Astrophysics Data System (ADS)

    Schwadron, N. A.; Opher, M.; Kasper, J.; Mewaldt, R.; Moebius, E.; Spence, H. E.; Zurbuchen, T. H.

    2016-11-01

    particle, and cosmic ray distributions to diagnose the changing space environment and understand the fundamental origins of particle acceleration. This paper, the first citable reference for IMAP, is similar to an unpublished whitepaper that was presented to the National Academies of Sciences, Engineering and Medicine Committee for Solar and Space Physics. We provide the IMAP objectives and instrument straw man traced from the Solar and Space Physics Decadal Survey. It is fitting that our paper is published in the volume of papers that celebrates the 80th birthday of Ed Stone.

  11. 46 CFR 160.052-3a - Materials-Dee ring and snap hook assemblies and other instruments of closure for buoyant vests.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... instruments of closure for buoyant vests. 160.052-3a Section 160.052-3a Shipping COAST GUARD, DEPARTMENT OF... LIFESAVING EQUIPMENT Specification for a Buoyant Vest, Unicellular Plastic Foam, Adult and Child § 160.052-3a Materials—Dee ring and snap hook assemblies and other instruments of closure for buoyant vests. (a...

  12. 46 CFR 160.047-3a - Materials-Dee ring and snap hook assemblies and other instruments of closure for buoyant vests.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... instruments of closure for buoyant vests. 160.047-3a Section 160.047-3a Shipping COAST GUARD, DEPARTMENT OF... LIFESAVING EQUIPMENT Specification for a Buoyant Vest, Kapok or Fibrous Glass, Adult and Child § 160.047-3a Materials—Dee ring and snap hook assemblies and other instruments of closure for buoyant vests. (a...

  13. 46 CFR 160.047-3a - Materials-Dee ring and snap hook assemblies and other instruments of closure for buoyant vests.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... instruments of closure for buoyant vests. 160.047-3a Section 160.047-3a Shipping COAST GUARD, DEPARTMENT OF... LIFESAVING EQUIPMENT Specification for a Buoyant Vest, Kapok or Fibrous Glass, Adult and Child § 160.047-3a Materials—Dee ring and snap hook assemblies and other instruments of closure for buoyant vests. (a...

  14. 46 CFR 160.047-3a - Materials-Dee ring and snap hook assemblies and other instruments of closure for buoyant vests.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... instruments of closure for buoyant vests. 160.047-3a Section 160.047-3a Shipping COAST GUARD, DEPARTMENT OF... LIFESAVING EQUIPMENT Specification for a Buoyant Vest, Kapok or Fibrous Glass, Adult and Child § 160.047-3a Materials—Dee ring and snap hook assemblies and other instruments of closure for buoyant vests. (a...

  15. 46 CFR 160.052-3a - Materials-Dee ring and snap hook assemblies and other instruments of closure for buoyant vests.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... instruments of closure for buoyant vests. 160.052-3a Section 160.052-3a Shipping COAST GUARD, DEPARTMENT OF... LIFESAVING EQUIPMENT Specification for a Buoyant Vest, Unicellular Plastic Foam, Adult and Child § 160.052-3a Materials—Dee ring and snap hook assemblies and other instruments of closure for buoyant vests. (a...

  16. 46 CFR 160.047-3a - Materials-Dee ring and snap hook assemblies and other instruments of closure for buoyant vests.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... instruments of closure for buoyant vests. 160.047-3a Section 160.047-3a Shipping COAST GUARD, DEPARTMENT OF... LIFESAVING EQUIPMENT Specification for a Buoyant Vest, Kapok or Fibrous Glass, Adult and Child § 160.047-3a Materials—Dee ring and snap hook assemblies and other instruments of closure for buoyant vests. (a...

  17. 46 CFR 160.052-3a - Materials-Dee ring and snap hook assemblies and other instruments of closure for buoyant vests.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... instruments of closure for buoyant vests. 160.052-3a Section 160.052-3a Shipping COAST GUARD, DEPARTMENT OF... LIFESAVING EQUIPMENT Specification for a Buoyant Vest, Unicellular Plastic Foam, Adult and Child § 160.052-3a Materials—Dee ring and snap hook assemblies and other instruments of closure for buoyant vests. (a...

  18. 46 CFR 160.052-3a - Materials-Dee ring and snap hook assemblies and other instruments of closure for buoyant vests.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... instruments of closure for buoyant vests. 160.052-3a Section 160.052-3a Shipping COAST GUARD, DEPARTMENT OF... LIFESAVING EQUIPMENT Specification for a Buoyant Vest, Unicellular Plastic Foam, Adult and Child § 160.052-3a Materials—Dee ring and snap hook assemblies and other instruments of closure for buoyant vests. (a...

  19. Fact Sheet: Protection of the Stratospheric Ozone: New Substitute in the Motor Vehicle Air Conditioning Sector under the Significant New Alternatives Policy (SNAP) Program

    EPA Pesticide Factsheets

    Under the Significant New Alternatives Policy (SNAP) program, EPA is listing HFO-1234yf as an acceptable substitute for ozone depleting substances (ODS) in motor vehicle air conditioning (MVAC) systems in new cars and other light duty-vehicles and is speci

  20. Probing dimensionality using a simplified 4-probe method.

    PubMed

    Kjeldby, Snorre B; Evenstad, Otto M; Cooil, Simon P; Wells, Justin W

    2017-10-04

    4-probe electrical measurements have been in existence for many decades. One of the most useful aspects of the 4-probe method is that it is not only possible to find the resistivity of a sample (independently of the contact resistances), but that it is also possible to probe the dimensionality of the sample. In theory, this is straightforward to achieve by measuring the 4-probe resistance as a function of probe separation. In practice, it is challenging to move all four probes with sufficient precision over the necessary range. Here, we present an alternative approach. We demonstrate that the dimensionality of the conductive path within a sample can be directly probed using a modified 4-probe method in which an unconventional geometry is exploited; three of the probes are rigidly fixed, and the position of only one probe is changed. This allows 2D and 3D (and other) contributions the to resistivity to be readily disentangled. The required experimental instrumentation can be vastly simplified relative to traditional variable spacing 4-probe instruments.

  1. The time resolved measurement of ultrashort terahertz-band electric fields without an ultrashort probe

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

    Walsh, D. A., E-mail: david.walsh@stfc.ac.uk; Snedden, E. W.; Jamison, S. P.

    The time-resolved detection of ultrashort pulsed THz-band electric field temporal profiles without an ultrashort laser probe is demonstrated. A non-linear interaction between a narrow-bandwidth optical probe and the THz pulse transposes the THz spectral intensity and phase information to the optical region, thereby generating an optical pulse whose temporal electric field envelope replicates the temporal profile of the real THz electric field. This optical envelope is characterised via an autocorrelation based FROG (frequency resolved optical gating) measurement, hence revealing the THz temporal profile. The combination of a narrow-bandwidth, long duration, optical probe, and self-referenced FROG makes the technique inherently immunemore » to timing jitter between the optical probe and THz pulse and may find particular application where the THz field is not initially generated via ultrashort laser methods, such as the measurement of longitudinal electron bunch profiles in particle accelerators.« less

  2. Two Step Acceleration Process of Electrons in the Outer Van Allen Radiation Belt by Time Domain Electric Field Bursts and Large Amplitude Chorus Waves

    NASA Astrophysics Data System (ADS)

    Agapitov, O. V.; Mozer, F.; Artemyev, A.; Krasnoselskikh, V.; Lejosne, S.

    2014-12-01

    A huge number of different non-linear structures (double layers, electron holes, non-linear whistlers, etc) have been observed by the electric field experiment on the Van Allen Probes in conjunction with relativistic electron acceleration in the Earth's outer radiation belt. These structures, found as short duration (~0.1 msec) quasi-periodic bursts of electric field in the high time resolution electric field waveform, have been called Time Domain Structures (TDS). They can quite effectively interact with radiation belt electrons. Due to the trapping of electrons into these non-linear structures, they are accelerated up to ~10 keV and their pitch angles are changed, especially for low energies (˜1 keV). Large amplitude electric field perturbations cause non-linear resonant trapping of electrons into the effective potential of the TDS and these electrons are then accelerated in the non-homogeneous magnetic field. These locally accelerated electrons create the "seed population" of several keV electrons that can be accelerated by coherent, large amplitude, upper band whistler waves to MeV energies in this two step acceleration process. All the elements of this chain acceleration mechanism have been observed by the Van Allen Probes.

  3. Essay: Robert H. Siemann As Leader of the Advanced Accelerator Research Department

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

    Colby, Eric R.; Hogan, Mark J.; /SLAC

    Robert H. Siemann originally conceived of the Advanced Accelerator Research Department (AARD) as an academic, experimental group dedicated to probing the technical limitations of accelerators while providing excellent educational opportunities for young scientists. The early years of the Accelerator Research Department B, as it was then known, were dedicated to a wealth of mostly student-led experiments to examine the promise of advanced accelerator techniques. High-gradient techniques including millimeter-wave rf acceleration, beam-driven plasma acceleration, and direct laser acceleration were pursued, including tests of materials under rf pulsed heating and short-pulse laser radiation, to establish the ultimate limitations on gradient. As themore » department and program grew, so did the motivation to found an accelerator research center that brought experimentalists together in a test facility environment to conduct a broad range of experiments. The Final Focus Test Beam and later the Next Linear Collider Test Accelerator provided unique experimental facilities for AARD staff and collaborators to carry out advanced accelerator experiments. Throughout the evolution of this dynamic program, Bob maintained a department atmosphere and culture more reminiscent of a university research group than a national laboratory department. His exceptional ability to balance multiple roles as scientist, professor, and administrator enabled the creation and preservation of an environment that fostered technical innovation and scholarship.« less

  4. A Potent Peptidomimetic Inhibitor of Botulinum Neurotoxin Serotype A has a Very Different Conformation than SNAP-25 Substrate

    DTIC Science & Technology

    2008-10-07

    in a competent orientation for attack by the catalytic water in the protease, resulting in the cleavage of the peptide bond. A cocrystal structure of...in future struc- ture-based discovery and design investigations. Implications for BoNT/A LC Inhibitor Development Our cocrystal provides a new...the Met residues in I1 and SNAP-25 are shown as sticks, with the sulfur atom colored yellow. The Zn2+ is shown as a light blue sphere.The cocrystal

  5. Investigation of Coatings for Langmuir Probes in an Oxygen-Rich Space Environment

    NASA Astrophysics Data System (ADS)

    Samaniego, J. I.; Wang, X.; Andersson, L.; Malaspina, D.; Ergun, R.; Horanyi, M.

    2017-12-01

    The surface properties of the Langmuir probes, such as the one on the MAVEN mission, will change after exposure to upper planetary atmospheres where high concentrations of atomic oxygen and other oxidizing compounds are present. TiN (Titanium Nitride) or DAG (a resin based graphite dispersion) are the most common coatings for current Langmuir probes, yet both of these coatings pose issues when exposed to oxygen-rich space environment. TiN showed reduced surface conductivity while the DAG layers erode with exposure to oxygen. It is known that Iridium (Ir) and Rhenium (Rh) are difficult to oxidize and maintain high conductivity even in their oxidized forms, suggesting them to be good candidates for probe coatings. Oxidation of most metals creates a resistive layer on the surface of the probe that will affect the amount of current being collected at a given voltage during the probe sweep and therefore affect the accuracy of plasma parameters determined by the Langmuir probe (e.g. density, temperature). We present the results of the oxidation effect on the current-voltage curves (I-V curves) and therefore the resulting measured plasma parameters of Ir and Rh wire probes compared with other control metals and coatings (Cu, Ni, TiN) in controlled plasma environments. The oxidation process is performed in an oxygen plasma chamber in which both O+ and O2+ are created and accelerated toward the probes with energies < 10 eV. An argon plasma chamber is used to compare the probe's I-V curves before and after the oxidation process. Our preliminary results indicate that iridium shows the least effect of oxidation on the probe measurements. The second objective of this study is to identify methods that can be used in orbit to clean the surface of Langmuir probes to minimize the effect of exposure to oxidizing compounds.

  6. Long-Wavelength 640 x 486 GaAs/AlGaAs Quantum Well Infrared Photodetector Snap-Shot Camera

    NASA Technical Reports Server (NTRS)

    Gunapala, Sarath D.; Bandara, Sumith V.; Liu, John K.; Hong, Winn; Sundaram, Mani; Maker, Paul D.; Muller, Richard E.; Shott, Craig A.; Carralejo, Ronald

    1998-01-01

    A 9-micrometer cutoff 640 x 486 snap-shot quantum well infrared photodetector (QWIP) camera has been demonstrated. The performance of this QWIP camera is reported including indoor and outdoor imaging. The noise equivalent differential temperature (NE.deltaT) of 36 mK has been achieved at 300 K background with f/2 optics. This is in good agreement with expected focal plane array sensitivity due to the practical limitations on charge handling capacity of the multiplexer, read noise, bias voltage, and operating temperature.

  7. Physics Program at COSY-Juelich with Polarized Hadronic Probes

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

    Kacharava, Andro

    2009-08-04

    Hadron physics aims at a fundamental understanding of all particles and their interactions that are subject to the strong force. Experiments using hadronic probes could contribute to shed light on open questions on the structure of hadrons and their interaction as well as the symmetries of nature. The COoler SYnchrotron COSY at the Forschungszentrum Juelich accelerates protons and deuterons with momenta up to 3.7 GeV/c. The availability of both an electron cooler as well as a stochastic beam cooling system allows for precision measurements, using polarized proton and deuteron beams in combination with polarized Hydrogen or Deuterium targets.This contribution summarizesmore » the ongoing physics program at the COSY facility using ANKE, WASA and TOF detector systems with polarized hadronic probes, highlighting recent results and outlining the new developments.« less

  8. Longitudinal β-Amyloid Deposition and Hippocampal Volume in Preclinical Alzheimer Disease and Suspected Non-Alzheimer Disease Pathophysiology.

    PubMed

    Gordon, Brian A; Blazey, Tyler; Su, Yi; Fagan, Anne M; Holtzman, David M; Morris, John C; Benzinger, Tammie L S

    2016-10-01

    define ND, t = 0.84 [P = .40]). Later preclinical stages (stages 1 and 2+) had elevated Aβ accumulation. Using hippocampal volume to define ND, individuals with stage 1 had accelerated Aβ accumulation relative to stage 0 (t = 11.06; P < .001), stage 2+ (t = 2.10; P = .04), and SNAP (t = 9.32; P < .001), and those with stage 2+ had accelerated Aβ accumulation relative to stage 0 (t = 4.38; P < .001) and SNAP (t = 4.08; P < .001). When ND was defined using tau and ptau, individuals with stage 2+ had accelerated Aβ accumulation relative to stage 0 (t = 4.96) and SNAP (t = 4.06), and those with stage 1 had accelerated Aβ accumulation relative to stage 0 (t = 8.44) and SNAP (t = 6.61) (P < .001 for all comparisons). When ND was defined using cerebrospinal fluid biomarkers, individuals with stage 2+ had accelerated hippocampal atrophy relative to stage 0 (t = -3.41; P < .001), stage 1 (t = -2.48; P = .03), and SNAP (t = -2.26; P = .03). More advanced preclinical stages of AD have greater longitudinal Aβ accumulation. SNAP appears most likely to capture inherent individual variability in brain structure or to represent comorbid pathologic features rather than early emerging AD. Low hippocampal volumes or elevated levels of tau or ptau in isolation may not accurately represent ongoing neurodegenerative processes.

  9. Disposition of toxic PCB congeners in snapping turtle eggs: expressed as toxic equivalents of TCDD

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

    Bryan, A.M.; Stone, W.B.; Olafsson, P.G.

    1987-11-01

    Studies of snapping turtles, taken from the region of the Upper Hudson River, in New York State, revealed exceedingly high levels of PCBs in the adipose tissue. There is evidence to suggest that large reserves of fat provide protection against chlorinated hydrocarbon toxicity. Such storage may protect snapping turtle eggs from disposition of toxic PCB congeners and account for the apparent absence of reports regarding detrimental effects on the hatchability of eggs from turtles living in the vicinity of the upper Hudson River. The present study was undertaken to determine if indeed these eggs are protected against disposition of toxicmore » PCB congeners by the presence of large reserves of fat. Although tissue volumes play an important role in determining the initial site of disposition, the major factor controlling the elimination of these compounds involves metabolism. For simple halogenated benzenes as well as for more complex halogenated biphenyls, oxidative metabolism catalyzed by P-448, occurs primarily at the site of two adjacent unsubstituted carbon atoms via arene oxide formation leading to the formation of water soluble metabolites. Toxicological studies have demonstrated that the most toxic PCB congeners, isosteriomers of tetrachlorodibenzo-p-dioxin (TCDD), require no metabolic activation. These compounds have chlorine atoms in the meta and para positions of both rings. It may be concluded that the structures of PCB congeners and isomers which favor induction of cytochrome P-448 are also those which are toxic and resist metabolism. It is the objective of the present study to determine if the heavy fat bodies of the female turtle provide a sufficiently large sink to retain the toxic congeners and prevent their incorporation into the eggs.« less

  10. Dietary exposure of BDE-47 and BDE-99 and effects on behavior, bioenergetics, and thyroid function in juvenile red-eared sliders (Trachemys scripta elegans) and common snapping turtles (Chelydra serpentina).

    PubMed

    Eisenreich, Karen M; Rowe, Christopher L

    2014-12-01

    Juvenile red-eared sliders (Trachemys scripta elegans) and snapping turtles (Chelydra serpentina) were fed food dosed with brominated diphenyl ether-47 (BDE-47) or BDE-99 for 6 mo beginning approximately 9 mo posthatch. During the exposure period, measurements of growth, bioenergetics, and behavior were made; thyroid function and accumulation were quantified postexposure. Whole-body concentrations of both congeners were lower in red-eared sliders compared with snapping turtles after 6 mo of exposure. Snapping turtles receiving BDE-47 had significantly elevated standard metabolic rates after 3 mo and 4 mo of exposure (p = 0.014 and p = 0.019, respectively). When exposed to BDE-99, red-eared sliders were slower to right themselves after having been inverted (p < 0.0001). Total glandular thyroxine concentrations were significantly reduced in red-eared sliders exposed to BDE-47 (mean control, 8080 ng/g; mean BDE-47, 5126 ng/g; p = 0.034). These results demonstrate that dietary exposure to BDE-47 and BDE-99 can elicit a suite of responses in 2 species of turtles, but that the red-eared slider appears to be a more sensitive species to the measured end points. © 2014 SETAC.

  11. Effect of dry mycelium of Penicillium chrysogenum fertilizer on soil microbial community composition, enzyme activities and snap bean growth.

    PubMed

    Wang, Bing; Liu, Huiling; Cai, Chen; Thabit, Mohamed; Wang, Pu; Li, Guomin; Duan, Ziheng

    2016-10-01

    The dry mycelium fertilizer (DMF) was produced from penicillin fermentation fungi mycelium (PFFM) following an acid-heating pretreatment to degrade the residual penicillin. In this study, it was applied into soil as fertilizer to investigate its effects on soil properties, phytotoxicity, microbial community composition, enzyme activities, and growth of snap bean in greenhouse. As the results show, pH, total nitrogen, total phosphorus, total potassium, and organic matter of soil with DMF treatments were generally higher than CON treatment. In addition, the applied DMF did not cause heavy metal and residual drug pollution of the modified soil. The lowest GI values (<0.3) were recorded at DMF8 (36 kg DMF/plat) on the first days after applying the fertilizer, indicating that severe phytotoxicity appeared in the DMF8-modified soil. Results of microbial population and enzyme activities illustrated that DMF was rapidly decomposed and the decomposition process significantly affected microbial growth and enzyme activities. The DMF-modified soil phytotoxicity decreased at the late fertilization time. DMF1 was considered as the optimum amount of DMF dose based on principal component analysis scores. Plant height and plant yield of snap bean were remarkably enhanced with the optimum DMF dose.

  12. Probing ultra-fast processes with high dynamic range at 4th-generation light sources: Arrival time and intensity binning at unprecedented repetition rates

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

    Kovalev, S.; Green, B.; Golz, T.

    Here, understanding dynamics on ultrafast timescales enables unique and new insights into important processes in the materials and life sciences. In this respect, the fundamental pump-probe approach based on ultra-short photon pulses aims at the creation of stroboscopic movies. Performing such experiments at one of the many recently established accelerator-based 4th-generation light sources such as free-electron lasers or superradiant THz sources allows an enormous widening of the accessible parameter space for the excitation and/or probing light pulses. Compared to table-top devices, critical issues of this type of experiment are fluctuations of the timing between the accelerator and external laser systemsmore » and intensity instabilities of the accelerator-based photon sources. Existing solutions have so far been only demonstrated at low repetition rates and/or achieved a limited dynamic range in comparison to table-top experiments, while the 4th generation of accelerator-based light sources is based on superconducting radio-frequency technology, which enables operation at MHz or even GHz repetition rates. In this article, we present the successful demonstration of ultra-fast accelerator-laser pump-probe experiments performed at an unprecedentedly high repetition rate in the few-hundred-kHz regime and with a currently achievable optimal time resolution of 13 fs (rms). Our scheme, based on the pulse-resolved detection of multiple beam parameters relevant for the experiment, allows us to achieve an excellent sensitivity in real-world ultra-fast experiments, as demonstrated for the example of THz-field-driven coherent spin precession.« less

  13. Probing ultra-fast processes with high dynamic range at 4th-generation light sources: Arrival time and intensity binning at unprecedented repetition rates.

    PubMed

    Kovalev, S; Green, B; Golz, T; Maehrlein, S; Stojanovic, N; Fisher, A S; Kampfrath, T; Gensch, M

    2017-03-01

    Understanding dynamics on ultrafast timescales enables unique and new insights into important processes in the materials and life sciences. In this respect, the fundamental pump-probe approach based on ultra-short photon pulses aims at the creation of stroboscopic movies. Performing such experiments at one of the many recently established accelerator-based 4th-generation light sources such as free-electron lasers or superradiant THz sources allows an enormous widening of the accessible parameter space for the excitation and/or probing light pulses. Compared to table-top devices, critical issues of this type of experiment are fluctuations of the timing between the accelerator and external laser systems and intensity instabilities of the accelerator-based photon sources. Existing solutions have so far been only demonstrated at low repetition rates and/or achieved a limited dynamic range in comparison to table-top experiments, while the 4th generation of accelerator-based light sources is based on superconducting radio-frequency technology, which enables operation at MHz or even GHz repetition rates. In this article, we present the successful demonstration of ultra-fast accelerator-laser pump-probe experiments performed at an unprecedentedly high repetition rate in the few-hundred-kHz regime and with a currently achievable optimal time resolution of 13 fs (rms). Our scheme, based on the pulse-resolved detection of multiple beam parameters relevant for the experiment, allows us to achieve an excellent sensitivity in real-world ultra-fast experiments, as demonstrated for the example of THz-field-driven coherent spin precession.

  14. Probing ultra-fast processes with high dynamic range at 4th-generation light sources: Arrival time and intensity binning at unprecedented repetition rates

    DOE PAGES

    Kovalev, S.; Green, B.; Golz, T.; ...

    2017-03-06

    Here, understanding dynamics on ultrafast timescales enables unique and new insights into important processes in the materials and life sciences. In this respect, the fundamental pump-probe approach based on ultra-short photon pulses aims at the creation of stroboscopic movies. Performing such experiments at one of the many recently established accelerator-based 4th-generation light sources such as free-electron lasers or superradiant THz sources allows an enormous widening of the accessible parameter space for the excitation and/or probing light pulses. Compared to table-top devices, critical issues of this type of experiment are fluctuations of the timing between the accelerator and external laser systemsmore » and intensity instabilities of the accelerator-based photon sources. Existing solutions have so far been only demonstrated at low repetition rates and/or achieved a limited dynamic range in comparison to table-top experiments, while the 4th generation of accelerator-based light sources is based on superconducting radio-frequency technology, which enables operation at MHz or even GHz repetition rates. In this article, we present the successful demonstration of ultra-fast accelerator-laser pump-probe experiments performed at an unprecedentedly high repetition rate in the few-hundred-kHz regime and with a currently achievable optimal time resolution of 13 fs (rms). Our scheme, based on the pulse-resolved detection of multiple beam parameters relevant for the experiment, allows us to achieve an excellent sensitivity in real-world ultra-fast experiments, as demonstrated for the example of THz-field-driven coherent spin precession.« less

  15. Diatoms on the carapace of common snapping turtles: Luticola spp. dominate despite spatial variation in assemblages

    PubMed Central

    Wu, Shelly C.; Bergey, Elizabeth A.

    2017-01-01

    Filamentous algae are often visible on the carapaces of freshwater turtles and these algae are dominated by a few species with varying geographic distributions. Compared to filamentous algae, little is known about the much more speciose microalgae on turtles. Our objectives were to compare the diatom flora on a single turtle species (the common snapping turtle, Chelydra serpentina) across part of its range to examine spatial patterns and determine whether specific diatom taxa were consistently associated with turtles (as occurs in the filamentous alga Basicladia spp.). Using preserved turtle specimens from museums, we systematically sampled diatoms on the carapaces of 25 snapping turtles across five states. The diverse diatom assemblages formed two groups–the southern Oklahoma group and the northern Illinois/Wisconsin/New York group, with Arkansas not differing from either group. Of the six diatom species found in all five states, four species are widespread, whereas Luticola cf. goeppertiana and L. cf. mutica are undescribed species, known only from turtles in our study. L. cf. goeppertiana comprised 83% of the diatom abundance on Oklahoma turtles and was relatively more abundant on southern turtles (Oklahoma and Arkansas) than on northern turtles (where mean abundance/state was > 10%). L. cf. mutica was the most abundant species (40%) on New York turtles. Some Luticola species are apparently turtle associates and results support a pattern of spatial variation in Luticola species, similar to that in Basicladia. Using museum specimens is an efficient and effective method to study the distribution of micro-epibionts. PMID:28192469

  16. Diatoms on the carapace of common snapping turtles: Luticola spp. dominate despite spatial variation in assemblages.

    PubMed

    Wu, Shelly C; Bergey, Elizabeth A

    2017-01-01

    Filamentous algae are often visible on the carapaces of freshwater turtles and these algae are dominated by a few species with varying geographic distributions. Compared to filamentous algae, little is known about the much more speciose microalgae on turtles. Our objectives were to compare the diatom flora on a single turtle species (the common snapping turtle, Chelydra serpentina) across part of its range to examine spatial patterns and determine whether specific diatom taxa were consistently associated with turtles (as occurs in the filamentous alga Basicladia spp.). Using preserved turtle specimens from museums, we systematically sampled diatoms on the carapaces of 25 snapping turtles across five states. The diverse diatom assemblages formed two groups-the southern Oklahoma group and the northern Illinois/Wisconsin/New York group, with Arkansas not differing from either group. Of the six diatom species found in all five states, four species are widespread, whereas Luticola cf. goeppertiana and L. cf. mutica are undescribed species, known only from turtles in our study. L. cf. goeppertiana comprised 83% of the diatom abundance on Oklahoma turtles and was relatively more abundant on southern turtles (Oklahoma and Arkansas) than on northern turtles (where mean abundance/state was > 10%). L. cf. mutica was the most abundant species (40%) on New York turtles. Some Luticola species are apparently turtle associates and results support a pattern of spatial variation in Luticola species, similar to that in Basicladia. Using museum specimens is an efficient and effective method to study the distribution of micro-epibionts.

  17. An oscillating wave energy converter with nonlinear snap-through Power-Take-Off systems in regular waves

    NASA Astrophysics Data System (ADS)

    Zhang, Xian-tao; Yang, Jian-min; Xiao, Long-fei

    2016-07-01

    Floating oscillating bodies constitute a large class of wave energy converters, especially for offshore deployment. Usually the Power-Take-Off (PTO) system is a directly linear electric generator or a hydraulic motor that drives an electric generator. The PTO system is simplified as a linear spring and a linear damper. However the conversion is less powerful with wave periods off resonance. Thus, a nonlinear snap-through mechanism with two symmetrically oblique springs and a linear damper is applied in the PTO system. The nonlinear snap-through mechanism is characteristics of negative stiffness and double-well potential. An important nonlinear parameter γ is defined as the ratio of half of the horizontal distance between the two springs to the original length of both springs. Time domain method is applied to the dynamics of wave energy converter in regular waves. And the state space model is used to replace the convolution terms in the time domain equation. The results show that the energy harvested by the nonlinear PTO system is larger than that by linear system for low frequency input. While the power captured by nonlinear converters is slightly smaller than that by linear converters for high frequency input. The wave amplitude, damping coefficient of PTO systems and the nonlinear parameter γ affect power capture performance of nonlinear converters. The oscillation of nonlinear wave energy converters may be local or periodically inter well for certain values of the incident wave frequency and the nonlinear parameter γ, which is different from linear converters characteristics of sinusoidal response in regular waves.

  18. Correction of static pressure on a research aircraft in accelerated flight using differential pressure measurements

    NASA Astrophysics Data System (ADS)

    Rodi, A. R.; Leon, D. C.

    2012-05-01

    Geometric altitude data from a combined Global Navigation Satellite System (GNSS) and inertial measurement unit (IMU) system on the University of Wyoming King Air research aircraft are used to estimate acceleration effects on static pressure measurement. Using data collected during periods of accelerated flight, comparison of measured pressure with that derived from GNSS/IMU geometric altitude show that errors exceeding 150 Pa can occur which is significant in airspeed and atmospheric air motion determination. A method is developed to predict static pressure errors from analysis of differential pressure measurements from a Rosemount model 858 differential pressure air velocity probe. The method was evaluated with a carefully designed probe towed on connecting tubing behind the aircraft - a "trailing cone" - in steady flight, and shown to have a precision of about ±10 Pa over a wide range of conditions including various altitudes, power settings, and gear and flap extensions. Under accelerated flight conditions, compared to the GNSS/IMU data, this algorithm predicts corrections to a precision of better than ±20 Pa. Some limiting factors affecting the precision of static pressure measurement on a research aircraft are examined.

  19. SNAP-Based Incentive Programs at Farmers' Markets: Adaptation Considerations for Temporary Assistance for Needy Families (TANF) Recipients.

    PubMed

    Wetherill, Marianna S; Williams, Mary B; Gray, Karen A

    2017-10-01

    To describe the design, implementation, and consumer response to a coupon-style intervention aimed to increase Supplemental Nutrition Assistance Program (SNAP) use at a farmers' market (FM) among Temporary Assistance for Needy Families (TANF) participants. A quasi-experimental trial to evaluate redemption response to 2 coupon interventions; baseline surveys characterized coupon redeemers and non-redeemers. Urban. The TANF recipients were assigned to either a plain (n = 124) or targeted marketing coupon intervention (n = 130). Both groups received 10 $2 coupons to double fruit and vegetable SNAP purchases at the FM. The targeted marketing group also received an oral presentation designed to reduce perceived barriers to FM use. Coupon redemption. The researchers used t tests and chi-square/Fisher exact tests to examine associations between redeemers and non-redeemers; logistic regression was used to adjust for the intervention. No male and few female participants redeemed coupons (6.3%). Among women, those with knowledge of vegetable preparation were 3 times more likely to redeem coupons than were those with little or no knowledge (odds ratio = 3.77; 95% confidence interval, 1.03-13.77). Stand-alone coupon incentive programs may not be a high-reach strategy for encouraging FM use among the population using TANF. Complementary strategies to build vegetable preparation knowledge and skills are needed. Copyright © 2017 Society for Nutrition Education and Behavior. Published by Elsevier Inc. All rights reserved.

  20. Comparative evaluation of probing depth and clinical attachment level using a manual probe and Florida probe.

    PubMed

    Kour, Amandeep; Kumar, Ashish; Puri, Komal; Khatri, Manish; Bansal, Mansi; Gupta, Geeti

    2016-01-01

    To compare and evaluate the intra- and inter-examiner efficacy and reproducibility of the first-generation manual (Williams) probe and the third-generation Florida probe in terms of measuring pocket probing depth (PD) and clinical attachment level (CAL). Forty subjects/4000 sites were included in this comparative, cross-sectional study. Group- and site-wise categorizations were done. Based on gingival index, PD, and CAL, patients were divided into four groups, i.e., periodontally healthy, gingivitis, mild to moderate periodontitis, and severe periodontitis. Further, based on these parameters, a total of 4000 sites, with 1000 sites in each category randomly selected from these 40 patients, were taken. Full mouth PD and CAL measurements were recorded with two probes, by Examiner 1 and on Ramfjord teeth by Examiner 2. Full mouth and Ramfjord teeth group- and site-wise PD obtained with the manual probe by both the examiners were statistically significantly deeper than that obtained with the Florida probe. The full mouth and Ramfjord teeth mean CAL measurement by Florida probe was higher as compared to manual probe in mild to moderate periodontitis group and sites, whereas in severe periodontitis group and sites, manual probe recorded higher CAL as compared to Florida probe. Mean PD and CAL measurements were deeper with the manual probe as compared to the Florida probe in all the groups and sites, except for the mild-moderate periodontitis group and sites where the CAL measurements with the manual probe were less than the Florida probe. Manual probe was more reproducible and showed less interexaminer variability as compared to the Florida probe.

  1. Report of dysgerminoma in the ovaries of a snapping turtle (Chelydra serpentina) with discussion of ovarian neoplasms reported in reptilians and women.

    PubMed

    Machotka, S V; Wisser, J; Ippen, R; Nawab, E

    1992-01-01

    A malnourished, captive, young adult (weight-11 kg, carapace length-25 cm), female snapping turtle (Chelydra serpentina) was presented for examination and treatment of malnutrition and multiple carapace necroses. Because treatment was unsuccessful, the animal was euthanatized and necropsied. The main necropsy observations showed the presence of a 9 cm greyish-white/yellow, soft, fleshy to fatlike mass involving the right ovary near the oviduct opening and multiple similar, pea-to-walnut sized masses involving both ovaries. Microscopic examination of formalin fixed, hematoxylin and eosin and silver stained tissue sections revealed the masses to be composed of primordial germ cells arranged in a pattern morphologically compatible with dysgerminoma as described in women and other mammals. Very rarely have ovarian neoplasms been reported in turtles or other reptiles. This is the first neoplasm described in the snapping turtle ovary and the first dysgerminoma reported in reptilians. A tabulation of previously documented ovarian neoplasia in reptiles and a comparison of this cancer to those occurring in women will be discussed.

  2. New Signal Amplification Strategy Using Semicarbazide as Co-reaction Accelerator for Highly Sensitive Electrochemiluminescent Aptasensor Construction.

    PubMed

    Ma, Meng-Nan; Zhuo, Ying; Yuan, Ruo; Chai, Ya-Qin

    2015-11-17

    A highly sensitive electrochemiluminescent (ECL) aptasensor was constructed using semicarbazide (Sem) as co-reaction accelerator to promote the ECL reaction rate of CdTe quantum dots (CdTe QDs) and the co-reactant of peroxydisulfate (S2O8(2-)) for boosting signal amplification. The co-reaction accelerator is a species that when it is introduced into the ECL system containing luminophore and co-reactant, it can interact with co-reactant rather than luminophore to promote the ECL reaction rate of luminophore and co-reactant; thus the ECL signal is significantly amplified in comparison with that in which only luminophore and co-reactant are present. In this work, the ECL signal probes were first fabricated by alternately assembling the Sem and Au nanoparticles (AuNPs) onto the surfaces of hollow Au nanocages (AuNCs) via Au-N bond to obtain the multilayered nanomaterials of (AuNPs-Sem)n-AuNCs for immobilizing amino-terminated detection aptamer of thrombin (TBA2). Notably, the Sem with two -NH2 terminal groups could not only serve as cross-linking reagent to assemble AuNPs and AuNCs but also act as co-reaction accelerator to enhance the ECL reaction rate of CdTe QDs and S2O8(2-) for signal amplification. With the sandwich-type format, TBA2 signal probes could be trapped on the CdTe QD-based sensing interface in the presence of thrombin (TB) to achieve a considerably enhanced ECL signal in S2O8(2-) solution. As a result, the Sem in the TBA2 signal probes could accelerate the reduction of S2O8(2-) to produce the more oxidant mediators of SO4(•-), which further boosted the production of excited states of CdTe QDs to emit light. With the employment of the novel co-reaction accelerator Sem, the proposed ECL biosensor exhibited ultrahigh sensitivity to quantify the concentration of TB from 1 × 10(-7) to 1 nM with a detection limit of 0.03 fM, which demonstrated that the co-reaction accelerator could provide a simple, efficient, and low-cost approach for signal

  3. Self-mapping the longitudinal field structure of a nonlinear plasma accelerator cavity

    DOE PAGES

    Clayton, C. E.; Adli, E.; Allen, J.; ...

    2016-08-16

    The preservation of emittance of the accelerating beam is the next challenge for plasma-based accelerators envisioned for future light sources and colliders. The field structure of a highly nonlinear plasma wake is potentially suitable for this purpose but has not been yet measured. Here we show that the longitudinal variation of the fields in a nonlinear plasma wakefield accelerator cavity produced by a relativistic electron bunch can be mapped using the bunch itself as a probe. We find that, for much of the cavity that is devoid of plasma electrons, the transverse force is constant longitudinally to within ±3% (r.m.s.).more » Moreover, comparison of experimental data and simulations has resulted in mapping of the longitudinal electric field of the unloaded wake up to 83 GV m –1 to a similar degree of accuracy. Lastly, these results bode well for high-gradient, high-efficiency acceleration of electron bunches while preserving their emittance in such a cavity.« less

  4. Self-mapping the longitudinal field structure of a nonlinear plasma accelerator cavity

    PubMed Central

    Clayton, C. E.; Adli, E.; Allen, J.; An, W.; Clarke, C. I.; Corde, S.; Frederico, J.; Gessner, S.; Green, S. Z.; Hogan, M. J.; Joshi, C.; Litos, M.; Lu, W.; Marsh, K. A.; Mori, W. B.; Vafaei-Najafabadi, N.; Xu, X.; Yakimenko, V.

    2016-01-01

    The preservation of emittance of the accelerating beam is the next challenge for plasma-based accelerators envisioned for future light sources and colliders. The field structure of a highly nonlinear plasma wake is potentially suitable for this purpose but has not been yet measured. Here we show that the longitudinal variation of the fields in a nonlinear plasma wakefield accelerator cavity produced by a relativistic electron bunch can be mapped using the bunch itself as a probe. We find that, for much of the cavity that is devoid of plasma electrons, the transverse force is constant longitudinally to within ±3% (r.m.s.). Moreover, comparison of experimental data and simulations has resulted in mapping of the longitudinal electric field of the unloaded wake up to 83 GV m−1 to a similar degree of accuracy. These results bode well for high-gradient, high-efficiency acceleration of electron bunches while preserving their emittance in such a cavity. PMID:27527569

  5. Association among SNAP-25 Gene "Dd"eI and "Mnl"I Polymorphisms and Hemodynamic Changes during Methylphenidate Use: A Functional Near-Infrared Spectroscopy Study

    ERIC Educational Resources Information Center

    Oner, Ozgur; Akin, Ata; Herken, Hasan; Erdal, Mehmet Emin; Ciftci, Koray; Ay, Mustafa Ertan; Bicer, Duygu; Oncu, Bedriye; Bozkurt, Ozlem Hekim; Munir, Kerim; Yazgan, Yanki

    2011-01-01

    Objective: To investigate the interaction of treatment-related hemodynamic changes with genotype status for Synaptosomal associated protein 25 (SNAP-25) gene in participants with attention deficit hyperactivity disorder (ADHD) on and off single dose short-acting methylphenidate treatment with functional near-infrared spectroscopy (fNIRS). Method:…

  6. Subcellular localization of proteins in the anaerobic sulfate reducer Desulfovibrio vulgaris via SNAP-tag labeling and photoconversion

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

    Gorur, A.; Leung, C. M.; Jorgens, D.

    2010-06-01

    Systems Biology studies the temporal and spatial 3D distribution of macromolecular complexes with the aim that such knowledge will allow more accurate modeling of biological function and will allow mathematical prediction of cellular behavior. However, in order to accomplish accurate modeling precise knowledge of spatial 3D organization and distribution inside cells is necessary. And while a number of macromolecular complexes may be identified by its 3D structure and molecular characteristics alone, the overwhelming number of proteins will need to be localized using a reporter tag. GFP and its derivatives (XFPs) have been traditionally employed for subcelllar localization using photoconversion approaches,more » but this approach cannot be taken for obligate anaerobic bacteria, where the intolerance towards oxygen prevents XFP approaches. As part of the GTL-funded PCAP project (now ENIGMA) genetic tools have been developed for the anaerobe sulfate reducer Desulfovibrio vulgaris that allow the high-throughput generation of tagged-protein mutant strains, with a focus on the commercially available SNAP-tag cell system (New England Biolabs, Ipswich, MA), which is based on a modified O6-alkylguanine-DNA alkyltransferase (AGT) tag, that has a dead-end reaction with a modified O6-benzylguanine (BG) derivative and has been shown to function under anaerobic conditions. After initial challenges with respect to variability, robustness and specificity of the labeling signal we have optimized the labeling. Over the last year, as a result of the optimized labeling protocol, we now obtain robust labeling of 20 out of 31 SNAP strains. Labeling for 13 strains were confirmed at least five times. We have also successfully performed photoconversion on 5 of these 13 strains, with distinct labeling patterns for different strains. For example, DsrC robustly localizes to the periplasmic portion of the inner membrane, where as a DNA-binding protein localizes to the center of the cell

  7. Increases in snap bean and soybean seedling diseases associated with a chloride salt and changes in the micro-partitioning of tap root calcium

    USDA-ARS?s Scientific Manuscript database

    In a series of field experiments from 1995 through 2010, the incidence of seedling diseases of snap bean and soybean caused by Rhizoctonia solani, Macrophomina phaseolina, Pythium spp., and Fusarium spp. was greater with an application of KCl than with K2SO4 applied at 93 kg K/ha. To determine if th...

  8. Designing a sun-pointing Faraday cup for solar probe plus

    NASA Astrophysics Data System (ADS)

    Case, A. W.; Kasper, J. C.; Daigneau, P. S.; Caldwell, D.; Freeman, M.; Gauron, T.; Maruca, B. A.; Bookbinder, J.; Korreck, K. E.; Cirtain, J. W.; Effinger, M. E.; Halekas, J. S.; Larson, D. E.; Lazarus, A. J.; Stevens, M. L.; Taylor, E. R.; Wright, K. H., Jr.

    2013-06-01

    The NASA Solar Probe Plus (SPP) mission will be the first spacecraft to pass through the sub-Alfvénic solar corona. The objectives of the mission are to trace the flow of energy that heats and accelerates the solar corona and solar wind, to determine the structure and dynamics of the plasma and magnetic fields at the sources of the solar wind, and to explore mechanisms that accelerate and transport energetic particles. The Solar Wind Electrons, Alphas, and Protons (SWEAP) Investigation instrument suite on SPP will measure the bulk solar wind conditions in the inner heliosphere. SWEAP consists of the Solar Probe Cup (SPC), a sun-pointing Faraday Cup, and the Solar Probe ANalyzers (SPAN), a set of 3 electrostatic analyzers that will reside in the penumbra of SPP's thermal protection system and measure solar wind ions and electrons. SPP is scheduled to launch in 2018 into an equatorial solar orbit where a sequence of Venus gravity assists will gradually lower its closest solar approach to within 9.5 solar radii (RS) of the center of the Sun. The photon flux at 9.5 RS is more than 500 times greater than at 1 AU and therefore presents a design challenge for SPC, which will point directly at the Sun. SPC is derived from the Faraday cup instruments successfully flown on spacecraft from the beginning of the space age, but updated with high temperature materials to operate through the solar encounters. Current work includes both instrument design and the development of a testing approach capable of demonstrating adequate performance in encounter conditions. This paper will briefly discuss the suite as a whole, and then focus on the design and capabilities of SPC. We will also present the planned calibration and characterization of the instrument and the testing required to demonstrate the technological readiness of the design.

  9. Vibrational dynamics of hydrogen-bonded complexes in solutions studied with ultrafast infrared pump-probe spectroscopy.

    PubMed

    Banno, Motohiro; Ohta, Kaoru; Yamaguchi, Sayuri; Hirai, Satori; Tominaga, Keisuke

    2009-09-15

    In aqueous solution, the basis of all living processes, hydrogen bonding exerts a powerful effect on chemical reactivity. The vibrational energy relaxation (VER) process in hydrogen-bonded complexes in solution is sensitive to the microscopic environment around the oscillator and to the geometrical configuration of the hydrogen-bonded complexes. In this Account, we describe the use of time-resolved infrared (IR) pump-probe spectroscopy to study the vibrational dynamics of (i) the carbonyl CO stretching modes in protic solvents and (ii) the OH stretching modes of phenol and carboxylic acid. In these cases, the carbonyl group acts as a hydrogen-bond acceptor, whereas the hydroxyl group acts as a hydrogen-bond donor. These vibrational modes have different properties depending on their respective chemical bonds, suggesting that hydrogen bonding may have different mechanisms and effects on the VER of the CO and OH modes than previously understood. The IR pump-probe signals of the CO stretching mode of 9-fluorenone and methyl acetate in alcohol, as well as that of acetic acid in water, include several components with different time constants. Quantum chemical calculations indicate that the dynamical components are the result of various hydrogen-bonded complexes that form between solute and solvent molecules. The acceleration of the VER is due to the increasing vibrational density of states caused by the formation of hydrogen bonds. The vibrational dynamics of the OH stretching mode in hydrogen-bonded complexes were studied in several systems. For phenol-base complexes, the decay time constant of the pump-probe signal decreases as the band peak of the IR absorption spectrum shifts to lower wavenumbers (the result of changing the proton acceptor). For phenol oligomers, the decay time constant of the pump-probe signal decreases as the probe wavenumber decreases. These observations show that the VER time strongly correlates with the strength of hydrogen bonding. This

  10. Oligonucleotides as probes for studying polymerization reactions in dilute aqueous solution

    NASA Technical Reports Server (NTRS)

    Kolb, V.; Orgel, L. E.; Miller, S. L. (Principal Investigator)

    1994-01-01

    We have prepared a [32P]-labled oligonucleotide probe carrying a free primary amine at its 3'-terminus. This probe is used to initiate polymerization of aziridine (ethyleneimine) in aqueous solution. The nature of the oligomeric products and the kinetics of their formation are then monitored by gel electrophoresis. Our results are generally consistent with those obtained using conventional techniques. We have also investigated the effect of polyanionic templates on the rate of oligomerization of aziridine. We find that water-soluble polyanions generally accelerate the polymerization. The sodium salt of polymethacrylic acid is the most effective of the templates that we studied. The methods introduced in this paper should be applicable to a variety of polymerization reactions in aqueous solution. They should greatly simplify the screening of potentially prebiotic polymerization reactions.

  11. Compact Plasma Accelerator for Micropropulsion Applications

    NASA Technical Reports Server (NTRS)

    Foster, John E.

    2001-01-01

    There is a need for a low power, light-weight (compact), high specific impulse electric propulsion device to satisfy mission requirements for microsatellite (1 to 20 kg) class missions. Satisfying these requirements entails addressing the general problem of generating a sufficiently dense plasma within a relatively small volume and then accelerating it. In the work presented here, the feasibility of utilizing a magnetic cusp to generate a dense plasma over small length scales of order 1 mm is investigated. This approach could potentially mitigate scaling issues associated with conventional ion thruster plasma containment schemes. Plume and discharge characteristics were documented using a Faraday probe and a retarding potential analyzer.

  12. Remote Sensing Measurements of the Corona with the Solar Probe

    NASA Technical Reports Server (NTRS)

    Habbal, Shadia Rifai; Woo, Richard

    1996-01-01

    Remote sensing measurements of the solar corona are indespensible for the exploration of the source and acceleration regions of the solar wind which are inaccessible to in situ plasma, paritcles and field experiments.Furthermore, imaging the solar disk and coronal from the unique vantage point of the trajectory and the proximity of the Solar Probe spacecraft, will provide the first ever opportunity to explore the small scale structures within coronal holes and streamers from viewing angles and with spatial resolutions never attained before.

  13. Spectrophotometric probe

    DOEpatents

    Prather, W.S.; O'Rourke, P.E.

    1994-08-02

    A support structure is described bearing at least one probe for making spectrophotometric measurements of a fluid using a source of light and a spectrophotometer. The probe includes a housing with two optical fibers and a planoconvex lens. A sleeve bearing a mirror surrounds the housing. The lens is separated from the mirror by a fixed distance, defining an interior space for receiving a volume of the fluid sample. A plurality of throughholes extending through the sleeve communicate between the sample volume and the exterior of the probe, all but one hole bearing a screen. A protective jacket surrounds the probe. A hollow conduit bearing a tube is formed in the wall of the probe for venting any air in the interior space when fluid enters. The probe is held at an acute angle so the optic fibers carrying the light to and from the probe are not bent severely on emergence from the probe. 3 figs.

  14. Spectrophotometric probe

    DOEpatents

    Prather, William S.; O'Rourke, Patrick E.

    1994-01-01

    A support structure bearing at least one probe for making spectrophotometric measurements of a fluid using a source of light and a spectrophotometer. The probe includes a housing with two optical fibers and a planoconvex lens. A sleeve bearing a mirror surrounds the housing. The lens is separated from the mirror by a fixed distance, defining an interior space for receiving a volume of the fluid sample. A plurality of throughholes extending through the sleeve communicate between the sample volume and the exterior of the probe, all but one hole bearing a screen. A protective jacket surrounds the probe. A hollow conduit bearing a tube is formed in the wall of the probe for venting any air in the interior space when fluid enters. The probe is held at an acute angle so the optic fibers carrying the light to and from the probe are not bent severely on emergence from the probe.

  15. Nonlinear friction dynamics on polymer surface under accelerated movement

    NASA Astrophysics Data System (ADS)

    Aita, Yuuki; Asanuma, Natsumi; Takahashi, Akira; Mayama, Hiroyuki; Nonomura, Yoshimune

    2017-04-01

    Nonlinear phenomena on the soft material surface are one of the most exciting topics of chemical physics. However, only a few reports exist on the friction phenomena under accelerated movement, because friction between two solid surfaces is considered a linear phenomenon in many cases. We aim to investigate how nonlinear accelerated motion affects friction on solid surfaces. In the present study, we evaluate the frictional forces between two polytetrafluoroethylene (PTFE) resins using an advanced friction evaluation system. On PTFE surfaces, the normalized delay time δ, which is the time lag in the response of the friction force to the accelerated movement, is observed in the pre-sliding friction process. Under high-velocity conditions, kinetic friction increases with velocity. Based on these experimental results, we propose a two-phase nonlinear model including a pre-sliding process (from the beginning of sliding of a contact probe to the establishment of static friction) and a kinetic friction process. The present model consists of several factors including velocity, acceleration, stiffness, viscosity, and vertical force. The findings reflecting the viscoelastic properties of soft material is useful for various fields such as in the fabrication of clothes, cosmetics, automotive materials, and virtual reality systems as well as for understanding friction phenomena on soft material surfaces.

  16. On thermal stress failure of the SNAP-19A RTG heat shield

    NASA Technical Reports Server (NTRS)

    Pitts, W. C.; Anderson, L. A.

    1974-01-01

    Results of a study on thermal stress problems in an amorphous graphite heat shield that is part of the launch-abort protect system for the SNAP-19A radio-isotope thermoelectric generators (RTG) that will be used on the Viking Mars Lander are presended. The first result is from a thermal stress analysis of a full-scale RTG heat source that failed to survive a suborbital entry flight test, possibly due to thermal stress failure. It was calculated that the maximum stress in the heat shield was only 50 percent of the ultimate strength of the material. To provide information on the stress failure criterion used for this calculation, some heat shield specimens were fractured under abort entry conditions in a plasma arc facility. It was found that in regions free of stress concentrations the POCO graphite heat shield material did fracture when the local stress reached the ultimate uniaxial stress of the material.

  17. Pioneer Jupiter orbiter probe mission 1980, probe description

    NASA Technical Reports Server (NTRS)

    Defrees, R. E.

    1974-01-01

    The adaptation of the Saturn-Uranus Atmospheric Entry Probe (SUAEP) to a Jupiter entry probe is summarized. This report is extracted from a comprehensive study of Jovian missions, atmospheric model definitions and probe subsystem alternatives.

  18. Pulsed electromagnetic acceleration

    NASA Technical Reports Server (NTRS)

    Jahn, R. G.; Vonjaskowsky, W. F.; Clark, K. E.

    1973-01-01

    Direct measurements of the power deposited in the anode of a multimegawatt MPD accelerator using thermocouples attached to a thin shell anode reveal a dramatic decrease in the fractional anode power from 50% at 200 KW input power to less than 10% at 20 MW power. The corresponding local power flux peak at a value of 10,000 W/sq cm at the lip of the anode exhaust orifice, a distribution traced to a corresponding peak in the local current density at the anode. A comparison of voltage-current characteristics and spectral photographs of the MPD discharge using quartz, boron nitride and plexiglas insulators with various mass injection configurations led to the identification of different voltage modes and regions of ablation free operation. The technique of piezoelectric impact pressure measurement in the MPD exhaust flow was refined to account for the effects due to probe yaw angle.

  19. Isolation of pisumin, a novel antifungal protein from legumes of the sugar snap pea Pisum sativum var macrocarpon.

    PubMed

    Ye, X Y; Ng, T B

    2003-02-01

    An antifungal protein with a novel N-terminal sequence GVGAAYGCFG and a molecular mass of 31 kDa was isolated from the legumes of the sugar snap pea Pisum sativum var. macrocarpon. The protein, designated pisumin, exhibited antifungal activity against Coprinus comatus and Pleurotus ostreatus and much weaker activity against Fusarium oxysporum and Rhizoctonia solani. Pisumin inhibited cell-free translation in a rabbit reticulocyte lysate system with an IC(50) of 6 microM. Pisumin was similar to other leguminous antifungal proteins in that it was adsorbed on Affi-gel blue gel and CM-Sepharose.

  20. Investigations of ultrafast charge dynamics in laser-irradiated targets by a self probing technique employing laser driven protons

    NASA Astrophysics Data System (ADS)

    Ahmed, H.; Kar, S.; Cantono, G.; Nersisyan, G.; Brauckmann, S.; Doria, D.; Gwynne, D.; Macchi, A.; Naughton, K.; Willi, O.; Lewis, C. L. S.; Borghesi, M.

    2016-09-01

    The divergent and broadband proton beams produced by the target normal sheath acceleration mechanism provide the unique opportunity to probe, in a point-projection imaging scheme, the dynamics of the transient electric and magnetic fields produced during laser-plasma interactions. Commonly such experimental setup entails two intense laser beams, where the interaction produced by one beam is probed with the protons produced by the second. We present here experimental studies of the ultra-fast charge dynamics along a wire connected to laser irradiated target carried out by employing a 'self' proton probing arrangement - i.e. by connecting the wire to the target generating the probe protons. The experimental data shows that an electromagnetic pulse carrying a significant amount of charge is launched along the wire, which travels as a unified pulse of 10s of ps duration with a velocity close to speed of light. The experimental capabilities and the analysis procedure of this specific type of proton probing technique are discussed.

  1. Probing the fusion of neutron-rich nuclei with re-accelerated radioactive beams

    DOE PAGES

    Vadas, J.; Singh, Varinderjit; Wiggins, B. B.; ...

    2018-03-27

    Here, we report the first measurement of the fusion excitation functions for 39,47K + 28Si at near-barrier energies. Evaporation residues resulting from the fusion process were identified by direct measurement of their energy and time-of-flight with high geometric efficiency. At the lowest incident energy, the cross section measured for the neutron-rich 47K-induced reaction is ≈6 times larger than that of the β-stable system. This experimental approach, both in measurement and in analysis, demonstrates how to efficiently measure fusion with low-intensity re-accelerated radioactive beams, establishing the framework for future studies.

  2. Probing the fusion of neutron-rich nuclei with re-accelerated radioactive beams

    NASA Astrophysics Data System (ADS)

    Vadas, J.; Singh, Varinderjit; Wiggins, B. B.; Huston, J.; Hudan, S.; deSouza, R. T.; Lin, Z.; Horowitz, C. J.; Chbihi, A.; Ackermann, D.; Famiano, M.; Brown, K. W.

    2018-03-01

    We report the first measurement of the fusion excitation functions for K,4739+28Si at near-barrier energies. Evaporation residues resulting from the fusion process were identified by direct measurement of their energy and time of flight with high geometric efficiency. At the lowest incident energy, the cross section measured for the neutron-rich 47K-induced reaction is ≈6 times larger than that of the β -stable system. This experimental approach, both in measurement and in analysis, demonstrates how to efficiently measure fusion with low-intensity re-accelerated radioactive beams, establishing the framework for future studies.

  3. Probing the fusion of neutron-rich nuclei with re-accelerated radioactive beams

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

    Vadas, J.; Singh, Varinderjit; Wiggins, B. B.

    Here, we report the first measurement of the fusion excitation functions for 39,47K + 28Si at near-barrier energies. Evaporation residues resulting from the fusion process were identified by direct measurement of their energy and time-of-flight with high geometric efficiency. At the lowest incident energy, the cross section measured for the neutron-rich 47K-induced reaction is ≈6 times larger than that of the β-stable system. This experimental approach, both in measurement and in analysis, demonstrates how to efficiently measure fusion with low-intensity re-accelerated radioactive beams, establishing the framework for future studies.

  4. GPU Accelerated Chemical Similarity Calculation for Compound Library Comparison

    PubMed Central

    Ma, Chao; Wang, Lirong; Xie, Xiang-Qun

    2012-01-01

    Chemical similarity calculation plays an important role in compound library design, virtual screening, and “lead” optimization. In this manuscript, we present a novel GPU-accelerated algorithm for all-vs-all Tanimoto matrix calculation and nearest neighbor search. By taking advantage of multi-core GPU architecture and CUDA parallel programming technology, the algorithm is up to 39 times superior to the existing commercial software that runs on CPUs. Because of the utilization of intrinsic GPU instructions, this approach is nearly 10 times faster than existing GPU-accelerated sparse vector algorithm, when Unity fingerprints are used for Tanimoto calculation. The GPU program that implements this new method takes about 20 minutes to complete the calculation of Tanimoto coefficients between 32M PubChem compounds and 10K Active Probes compounds, i.e., 324G Tanimoto coefficients, on a 128-CUDA-core GPU. PMID:21692447

  5. A new approach to accelerated drug-excipient compatibility testing.

    PubMed

    Sims, Jonathan L; Carreira, Judith A; Carrier, Daniel J; Crabtree, Simon R; Easton, Lynne; Hancock, Stephen A; Simcox, Carol E

    2003-01-01

    The purpose of this study was to develop a method of qualitatively predicting the most likely degradants in a formulation or probing specific drug-excipient interactions in a significantly shorter time frame than the typical 1 month storage testing. In the example studied, accelerated storage testing of a solid dosage form at 50 degrees C, the drug substance SB-243213-A degraded via the formation of two oxidative impurities. These impurities reached a level of 1% PAR after 3 months. Various stressing methods were examined to try to recreate this degradation and in doing so provide a practical and reliable method capable of predicting drug-excipient interactions. The technique developed was able to mimic the 1-month's accelerated degradation in just 1 hr. The method was suitable for automated analysis, capable of multisample stressing, and ideal for use in drug-excipient compatibility screening.

  6. Acceleration modules in linear induction accelerators

    NASA Astrophysics Data System (ADS)

    Wang, Shao-Heng; Deng, Jian-Jun

    2014-05-01

    The Linear Induction Accelerator (LIA) is a unique type of accelerator that is capable of accelerating kilo-Ampere charged particle current to tens of MeV energy. The present development of LIA in MHz bursting mode and the successful application into a synchrotron have broadened LIA's usage scope. Although the transformer model is widely used to explain the acceleration mechanism of LIAs, it is not appropriate to consider the induction electric field as the field which accelerates charged particles for many modern LIAs. We have examined the transition of the magnetic cores' functions during the LIA acceleration modules' evolution, distinguished transformer type and transmission line type LIA acceleration modules, and re-considered several related issues based on transmission line type LIA acceleration module. This clarified understanding should help in the further development and design of LIA acceleration modules.

  7. Frequency-Domain Streak Camera and Tomography for Ultrafast Imaging of Evolving and Channeled Plasma Accelerator Structures

    NASA Astrophysics Data System (ADS)

    Li, Zhengyan; Zgadzaj, Rafal; Wang, Xiaoming; Reed, Stephen; Dong, Peng; Downer, Michael C.

    2010-11-01

    We demonstrate a prototype Frequency Domain Streak Camera (FDSC) that can capture the picosecond time evolution of the plasma accelerator structure in a single shot. In our prototype Frequency-Domain Streak Camera, a probe pulse propagates obliquely to a sub-picosecond pump pulse that creates an evolving nonlinear index "bubble" in fused silica glass, supplementing a conventional Frequency Domain Holographic (FDH) probe-reference pair that co-propagates with the "bubble". Frequency Domain Tomography (FDT) generalizes Frequency-Domain Streak Camera by probing the "bubble" from multiple angles and reconstructing its morphology and evolution using algorithms similar to those used in medical CAT scans. Multiplexing methods (Temporal Multiplexing and Angular Multiplexing) improve data storage and processing capability, demonstrating a compact Frequency Domain Tomography system with a single spectrometer.

  8. Studying astrophysical particle acceleration with laser-driven plasmas

    NASA Astrophysics Data System (ADS)

    Fiuza, Frederico

    2016-10-01

    The acceleration of non-thermal particles in plasmas is critical for our understanding of explosive astrophysical phenomena, from solar flares to gamma ray bursts. Particle acceleration is thought to be mediated by collisionless shocks and magnetic reconnection. The microphysics underlying these processes and their ability to efficiently convert flow and magnetic energy into non-thermal particles, however, is not yet fully understood. By performing for the first time ab initio 3D particle-in-cell simulations of the interaction of both magnetized and unmagnetized laser-driven plasmas, it is now possible to identify the optimal parameters for the study of particle acceleration in the laboratory relevant to astrophysical scenarios. It is predicted for the Omega and NIF laser conditions that significant non-thermal acceleration can occur during magnetic reconnection of laser-driven magnetized plasmas. Electrons are accelerated by the electric field near the X-points and trapped in contracting magnetic islands. This leads to a power-law tail extending to nearly a hundred times the thermal energy of the plasma and that contains a large fraction of the magnetic energy. The study of unmagnetized interpenetrating plasmas also reveals the possibility of forming collisionless shocks mediated by the Weibel instability on NIF. Under such conditions, both electrons and ions can be energized by scattering out of the Weibel-mediated turbulence. This also leads to power-law spectra that can be detected experimentally. The resulting experimental requirements to probe the microphysics of plasma particle acceleration will be discussed, paving the way for the first experiments of these important processes in the laboratory. As a result of these simulations and theoretical analysis, there are new experiments being planned on the Omega, NIF, and LCLS laser facilities to test these theoretical predictions. This work was supported by the SLAC LDRD program and DOE Office of Science, Fusion

  9. Embryonic common snapping turtles (Chelydra serpentina) preferentially regulate intracellular tissue pH during acid-base challenges.

    PubMed

    Shartau, Ryan B; Crossley, Dane A; Kohl, Zachary F; Brauner, Colin J

    2016-07-01

    The nests of embryonic turtles naturally experience elevated CO2 (hypercarbia), which leads to increased blood PCO2  and a respiratory acidosis, resulting in reduced blood pH [extracellular pH (pHe)]. Some fishes preferentially regulate tissue pH [intracellular pH (pHi)] against changes in pHe; this has been proposed to be associated with exceptional CO2 tolerance and has never been identified in amniotes. As embryonic turtles may be CO2 tolerant based on nesting strategy, we hypothesized that they preferentially regulate pHi, conferring tolerance to severe acute acid-base challenges. This hypothesis was tested by investigating pH regulation in common snapping turtles (Chelydra serpentina) reared in normoxia then exposed to hypercarbia (13 kPa PCO2 ) for 1 h at three developmental ages: 70% and 90% of incubation, and yearlings. Hypercarbia reduced pHe but not pHi, at all developmental ages. At 70% of incubation, pHe was depressed by 0.324 pH units while pHi of brain, white muscle and lung increased; heart, liver and kidney pHi remained unchanged. At 90% of incubation, pHe was depressed by 0.352 pH units but heart pHi increased with no change in pHi of other tissues. Yearlings exhibited a pHe reduction of 0.235 pH units but had no changes in pHi of any tissues. The results indicate common snapping turtles preferentially regulate pHi during development, but the degree of response is reduced throughout development. This is the first time preferential pHi regulation has been identified in an amniote. These findings may provide insight into the evolution of acid-base homeostasis during development of amniotes, and vertebrates in general. © 2016. Published by The Company of Biologists Ltd.

  10. Analysis and Down Select of Flow Passages for Thermal Hydraulic Testing of a SNAP Derived Reactor

    NASA Technical Reports Server (NTRS)

    Godfroy, T. J.; Sadasivan, P.; Masterson, S.

    2007-01-01

    As past of the Vision for Space Exploration, man will return to the moon. To enable safe and productive time on the lunar surface will require adequate power resources. To provide the needed power and to give mission planners all landing site possibilities, including a permanently dark crater, a nuclear reactor provides the most options. Designed to be l00kWt providing approx. 25kWe this power plants would be very effective in delivering dependable, site non-specific power to crews or robotic missions on the lunar surface. An affordable reference reactor based upon the successful SNAP program of the 1960's and early 1970's has been designed by Los Alamos National Laboratory that will meet such a requirement. Considering current funding, environmental, and schedule limitations this lunar surface power reactor will be tested using non-nuclear simulators to simulate the heat from fission reactions. Currently a 25kWe surface power SNAP derivative reactor is in the early process of design and testing with collaboration between Los Alamos National Laboratory, Idaho National Laboratory, Glenn Research Center, Marshall Space Flight Center, and Sandia National Laboratory to ensure that this new design is affordable and can be tested using non-nuclear methods as have proven so effective in the past. This paper will discuss the study and down selection of a flow passage concept for a approx. 25kWe lunar surface power reactor. Several different flow passages designs were evaluated using computational fluid dynamics to determine pressure drop and a structural assessment to consider thermal and stress of the passage walls. The reactor design basis conditions are discussed followed by passage problem setup and results for each concept. A recommendation for passage design is made with rationale for selection.

  11. PROBING DYNAMICS OF ELECTRON ACCELERATION WITH RADIO AND X-RAY SPECTROSCOPY, IMAGING, AND TIMING IN THE 2002 APRIL 11 SOLAR FLARE

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

    Fleishman, Gregory D.; Nita, Gelu M.; Gary, Dale E.

    Based on detailed analysis of radio and X-ray observations of a flare on 2002 April 11 augmented by realistic three-dimensional modeling, we have identified a radio emission component produced directly at the flare acceleration region. This acceleration region radio component has distinctly different (1) spectrum, (2) light curves, (3) spatial location, and, thus, (4) physical parameters from those of the separately identified trapped or precipitating electron components. To derive evolution of physical parameters of the radio sources we apply forward fitting of the radio spectrum time sequence with the gyrosynchrotron source function with five to six free parameters. At themore » stage when the contribution from the acceleration region dominates the radio spectrum, the X-ray- and radio-derived electron energy spectral indices agree well with each other. During this time the maximum energy of the accelerated electron spectrum displays a monotonic increase with time from {approx}300 keV to {approx}2 MeV over roughly one minute duration indicative of an acceleration process in the form of growth of the power-law tail; the fast electron residence time in the acceleration region is about 2-4 s, which is much longer than the time of flight and so requires a strong diffusion mode there to inhibit free-streaming propagation. The acceleration region has a relatively strong magnetic field, B {approx} 120 G, and a low thermal density, n{sub e} {approx}< 2 Multiplication-Sign 10{sup 9} cm{sup -3}. These acceleration region properties are consistent with a stochastic acceleration mechanism.« less

  12. Preliminary assessment of the electromagnetic environment in the immediate vicinity of the ETA accelerator

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

    Cabayan, H.S.; Bogdan, E.; Zicker, J.

    The electromagnetic fields in the immediate vicinity of the Experimental Test Accelerator (ETA) at the Lawrence Livermore Laboratory have been characterized. Various EM sensors that cover the frequency band from the very low frequencies up into the GHz region have been used. The report describes in detail the probes, the test set-up and the data processing techniques.

  13. Hydrodynamic ultrasonic probe

    DOEpatents

    Day, Robert A.; Conti, Armond E.

    1980-01-01

    An improved probe for in-service ultrasonic inspection of long lengths of a workpiece, such as small diameter tubing from the interior. The improved probe utilizes a conventional transducer or transducers configured to inspect the tubing for flaws and/or wall thickness variations. The probe utilizes a hydraulic technique, in place of the conventional mechanical guides or bushings, which allows the probe to move rectilinearly or rotationally while preventing cocking thereof in the tube and provides damping vibration of the probe. The probe thus has lower friction and higher inspection speed than presently known probes.

  14. An investigation into the effectiveness of smartphone experiments on students’ conceptual knowledge about acceleration

    NASA Astrophysics Data System (ADS)

    Mazzella, Alessandra; Testa, Italo

    2016-09-01

    This study is a first attempt to investigate effectiveness of smartphone-based activities on students’ conceptual understanding of acceleration. 143 secondary school students (15-16 years old) were involved in two types of activities: smartphone- and non-smartphone activities. The latter consisted in data logging and ‘cookbook’ activities. For the sake of comparison, all activities featured the same phenomena, i.e., the motion on an inclined plane and pendulum oscillations. A pre-post design was adopted, using open questionnaires as probes. Results show only weak statistical differences between the smartphone and non-smartphone groups. Students who followed smartphone activities were more able to design an experiment to measure acceleration and to correctly describe acceleration in a free fall motion. However, students of both groups had many difficulties in drawing acceleration vector along the trajectory of the studied motion. Results suggest that smartphone-based activities may be effective substitutes of traditional experimental settings and represent a valuable aid for teachers who want to implement laboratory activities at secondary school level. However, to achieve a deeper conceptual understanding of acceleration, some issues need to be addressed: what is the reference system of the built-in smartphone sensor; relationships between smartphone acceleration graphs and experimental setup; vector representation of the measured acceleration.

  15. Work on Planetary Atmospheres and Planetary Atmosphere Probes

    NASA Technical Reports Server (NTRS)

    Seiff, Alvin; Lester, Peter

    1999-01-01

    instrument performance, although performed greater than 5 years prior to Jupiter encounter. Capability of decoding the science data from the Experiment Data Record to be provided at encounter was developed and exercised using the tape recording of the first Cruise Checkout data. A team effort was organized to program the selection and combination of data words defining pressure, temperature, acceleration, turbulence, and engineering quantities; to apply decalibration algorithms to convert readings from digital numbers to physical quantities; and to organize the data into a suitable printout. A paper on the Galileo Atmosphere Structure Instrument was written and submitted for publication in a special issue of Space Science Reviews. At the Journal editor's request, the grantee reviewed other Probe instrument papers submitted for this special issue. Calibration data were carefully taken for all experiment sensors and accumulated over a period of 10 years. The data were analyzed, fitted with algorithms, and summarized in a calibration report for use in analyzing and interpreting data returned from Jupiter's atmosphere. The sensors included were the primary science pressure, temperature, and acceleration sensors, and the supporting engineering temperature sensors. This report was distributed to experiment coinvestigators and the Probe Project Office.

  16. Space Experiments with Particle Accelerators (SEPAC)

    NASA Technical Reports Server (NTRS)

    Obayashi, T.; Kawashima, N.; Kuriki, K.; Nagatomo, M.; Ninomiya, K.; Sasaki, S.; Ushirokawa, A.; Kudo, I.; Ejiri, M.; Roberts, W. T.

    1982-01-01

    Plans for SEPAC, an instrument array to be used on Spacelab 1 to study vehicle charging and neutralization, beam-plasma interaction in space, beam-atmospheric interaction exciting artificial aurora and airglow, and the electromagnetic-field configuration of the magnetosphere, are presented. The hardware, consisting of electron beam accelerator, magnetoplasma arcjet, neutral-gas plume generator, power supply, diagnostic package (photometer, plasma probes, particle analyzers, and plasma-wave package), TV monitor, and control and data-management unit, is described. The individual SEPAC experiments, the typical operational sequence, and the general outline of the SEPAC follow-on mission are discussed. Some of the experiments are to be joint ventures with AEPI (INS 003) and will be monitored by low-light-level TV.

  17. Physical limitations in sensors for a drag-free deep space probe

    NASA Technical Reports Server (NTRS)

    Juillerat, R.

    1971-01-01

    The inner perturbing forces acting on sensors were analyzed, taking into account the technological limitations imposed on the proof mass position pickup and proof mass acquisition system. The resulting perturbing accelerations are evaluated as a function of the drag-free sensor parameters. Perturbations included gravitational attraction, electrical action, magnetic action, pressure effects, radiation effects, and action of the position pickup. These data can be used to study the laws of guidance, providing an optimization of the space probe as a whole.

  18. Understanding non-equilibrium collisional and expansion effects in the solar wind with Parker Solar Probe

    NASA Astrophysics Data System (ADS)

    Korreck, K. E.; Klein, K. G.; Maruca, B.; Alterman, B. L.

    2017-12-01

    The evolution of the solar wind from the corona to the Earth and throughout the heliosphere is a complex interplay between local micro kinetics and large scale expansion effects. These processes in the solar wind need to be separated in order to understand and distinguish the dominant mechanism for heating and acceleration of the solar wind. With the upcoming launch in 2018 of Parker Solar Probe and the launch of Solar Orbiter after, addressing the local and global phenomena will be enabled with in situ measurements. Parker Solar Probe will go closer to the Sun than any previous mission enabling the ability to examine the solar wind at an early expansion age. This work examines the predictions for what will be seen inside of the 0.25 AU (54 solar radii) where Parker Solar Probe will take measurements and lays the groundwork for disentangling the expansion and collisional effects. In addition, methods of thermal plasma data analysis to determine the stability of the plasma in the Parker Solar Probe measurements will be discussed.

  19. Characterization of Akiyama probe applied to dual-probes atomic force microscope

    NASA Astrophysics Data System (ADS)

    Wang, Hequn; Gao, Sitian; Li, Wei; Shi, Yushu; Li, Qi; Li, Shi; Zhu, Zhendong

    2016-10-01

    The measurement of nano-scale line-width has always been important and difficult in the field of nanometer measurements, while the rapid development of integrated circuit greatly raises the demand again. As one kind of scanning probe microscope (SPM), atomic force microscope (AFM) can realize quasi three-dimensional measurement, which is widely used in nanometer scale line-width measurement. Our team researched a dual-probes atomic force microscope, which can eliminate the prevalent effect of probe width on measurement results. In dual-probes AFM system, a novel head are newly designed. A kind of self-sensing and self-exciting probes which is Nanosensors cooperation's patented probe—Akiyama probe, is used in this novel head. The Akiyama probe applied to dual-probe atomic force microscope is one of the most important issues. The characterization of Akiyama probe would affect performance and accuracy of the whole system. The fundamental features of the Akiyama probe are electrically and optically characterized in "approach-withdraw" experiments. Further investigations include the frequency response of an Akiyama probe to small mechanical vibrations externally applied to the tip and the effective loading force yielding between the tip and the sample during the periodic contact. We hope that the characterization of the Akiyama probe described in this paper will guide application for dual-probe atomic force microscope.

  20. Design of a 25-kWe Surface Reactor System Based on SNAP Reactor Technologies

    NASA Astrophysics Data System (ADS)

    Dixon, David D.; Hiatt, Matthew T.; Poston, David I.; Kapernick, Richard J.

    2006-01-01

    A Hastelloy-X clad, sodium-potassium (NaK-78) cooled, moderated spectrum reactor using uranium zirconium hydride (UZrH) fuel based on the SNAP program reactors is a promising design for use in surface power systems. This paper presents a 98 kWth reactor for a power system the uses multiple Stirling engines to produce 25 kWe-net for 5 years. The design utilizes a pin type geometry containing UZrHx fuel clad with Hastelloy-X and NaK-78 flowing around the pins as coolant. A compelling feature of this design is its use of 49.9% enriched U, allowing it to be classified as a category III-D attractiveness and reducing facility costs relative to highly-enriched space reactor concepts. Presented below are both the design and an analysis of this reactor's criticality under various safety and operations scenarios.

  1. Lateral-deflection-controlled friction force microscopy

    NASA Astrophysics Data System (ADS)

    Fukuzawa, Kenji; Hamaoka, Satoshi; Shikida, Mitsuhiro; Itoh, Shintaro; Zhang, Hedong

    2014-08-01

    Lateral-deflection-controlled dual-axis friction force microscopy (FFM) is presented. In this method, an electrostatic force generated with a probe-incorporated micro-actuator compensates for friction force in real time during probe scanning using feedback control. This equivalently large rigidity can eliminate apparent boundary width and lateral snap-in, which are caused by lateral probe deflection. The method can evolve FFM as a method for quantifying local frictional properties on the micro/nanometer-scale by overcoming essential problems to dual-axis FFM.

  2. Pitch Angle Dependence of Drift Resonant Ions Observed by the Van Allen Probes

    NASA Astrophysics Data System (ADS)

    Rankin, R.; Wang, C.; Wang, Y.; Zong, Q. G.; Zhou, X.

    2017-12-01

    Acceleration and modulation of ring current ions by poloidal mode ULF waves is investigated. A simplified MHD model of ULF waves in a dipole magnetic field is presented that includes phase mixing to perpendicular scales determined by the ionospheric Pedersen conductivity. The wave model is combined with a full Lorentz force test particle code to study drift and drift bounce resonance wave-particle interactions. Ion trajectories are traced backward-in-time to an assumed form of the distribution function, and Liouville's method is used to reconstruct the phase space density response (PSD) poloidal mode waves observed by the Van Allen Probes. In spite of its apparent simplicity, simulations using the wave and test particle models are able to explain the acceleration of ions and energy dispersion observed by the Van Allen Probes. The paper focuses on the pitch angle evolution of the initial PSD as it responds to the action of ULF waves. An interesting aspect of the study is the formation of butterfly ion distributions as ions make periodic radial oscillations across L. Ions become trapped in an effective potential well across a limited range of L and follow trajectories that cause them to surf along constant phase fronts. The impications of this new trapping mechanism for both ions and electrons is discussed.

  3. DIFFUSIVE SHOCK ACCELERATION SIMULATIONS OF RADIO RELICS

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

    Kang, Hyesung; Ryu, Dongsu; Jones, T. W., E-mail: kang@uju.es.pusan.ac.kr, E-mail: ryu@canopus.cnu.ac.kr, E-mail: twj@msi.umn.edu

    2012-09-01

    Recent radio observations have identified a class of structures, so-called radio relics, in clusters of galaxies. The radio emission from these sources is interpreted as synchrotron radiation from GeV electrons gyrating in {mu}G-level magnetic fields. Radio relics, located mostly in the outskirts of clusters, seem to associate with shock waves, especially those developed during mergers. In fact, they seem to be good structures to identify and probe such shocks in intracluster media (ICMs), provided we understand the electron acceleration and re-acceleration at those shocks. In this paper, we describe time-dependent simulations for diffusive shock acceleration at weak shocks that aremore » expected to be found in ICMs. Freshly injected as well as pre-existing populations of cosmic-ray (CR) electrons are considered, and energy losses via synchrotron and inverse Compton are included. We then compare the synchrotron flux and spectral distributions estimated from the simulations with those in two well-observed radio relics in CIZA J2242.8+5301 and ZwCl0008.8+5215. Considering that CR electron injection is expected to be rather inefficient at weak shocks with Mach number M {approx}< a few, the existence of radio relics could indicate the pre-existing population of low-energy CR electrons in ICMs. The implication of our results on the merger shock scenario of radio relics is discussed.« less

  4. Development of piezoelectric bistable energy harvester based on buckled beam with axially constrained end condition for human motion

    NASA Astrophysics Data System (ADS)

    Eltanany, Ali M.; Yoshimura, Takeshi; Fujimura, Norifumi; Ebied, Mohamed R.; Ali, Mohamed G. S.

    2017-10-01

    In this study, we aim to examine the triggering force for an efficient snap-through solution of hand shaking vibrations of a piezoelectric bistable energy harvester. The proposed structure works at very low frequencies with nearly continuous periodic vibrations. The static characterizations are presented as well as the dynamic characterizations based on the phase diagrams of velocity vs displacement, voltage vs displacement, and voltage vs input acceleration. The mass attached to the bistable harvester plays an important role in determining the acceleration needed for the snap-through action, and the explanation for this role is complex because of mass dependence on frequency/amplitude vibration. Various hand shaking vibration tests are performed to demonstrate the advantage of the proposed structure in harvesting energy from hand shaking vibration. The minimum input acceleration for snap-through action was 11.59 m/s2 with peaks of 15.76 and 2 m/s2 in the frequency range of 1.3-2.7 Hz, when an attached mass of 14.6 g is used. The maximum generated power at a buckling state of 0.5 mm is 11.3 µW for the test structure at 26 g. The experimental results obtained in this study indicate that power output harvesting of slow hand shaking vibrations at 10 µW and a load resistance of 1 MΩ.

  5. Intrinsic beam emittance of laser-accelerated electrons measured by x-ray spectroscopic imaging.

    PubMed

    Golovin, G; Banerjee, S; Liu, C; Chen, S; Zhang, J; Zhao, B; Zhang, P; Veale, M; Wilson, M; Seller, P; Umstadter, D

    2016-04-19

    The recent combination of ultra-intense lasers and laser-accelerated electron beams is enabling the development of a new generation of compact x-ray light sources, the coherence of which depends directly on electron beam emittance. Although the emittance of accelerated electron beams can be low, it can grow due to the effects of space charge during free-space propagation. Direct experimental measurement of this important property is complicated by micron-scale beam sizes, and the presence of intense fields at the location where space charge acts. Reported here is a novel, non-destructive, single-shot method that overcame this problem. It employed an intense laser probe pulse, and spectroscopic imaging of the inverse-Compton scattered x-rays, allowing measurement of an ultra-low value for the normalized transverse emittance, 0.15 (±0.06) π mm mrad, as well as study of its subsequent growth upon exiting the accelerator. The technique and results are critical for designing multi-stage laser-wakefield accelerators, and generating high-brightness, spatially coherent x-rays.

  6. Intrinsic beam emittance of laser-accelerated electrons measured by x-ray spectroscopic imaging

    DOE PAGES

    Golovin, G.; Banerjee, S.; Liu, C.; ...

    2016-04-19

    Here, the recent combination of ultra-intense lasers and laser-accelerated electron beams is enabling the development of a new generation of compact x-ray light sources, the coherence of which depends directly on electron beam emittance. Although the emittance of accelerated electron beams can be low, it can grow due to the effects of space charge during free-space propagation. Direct experimental measurement of this important property is complicated by micron-scale beam sizes, and the presence of intense fields at the location where space charge acts. Reported here is a novel, non-destructive, single-shot method that overcame this problem. It employed an intense lasermore » probe pulse, and spectroscopic imaging of the inverse-Compton scattered x-rays, allowing measurement of an ultra-low value for the normalized transverse emittance, 0.15 (±0.06) π mm mrad, as well as study of its subsequent growth upon exiting the accelerator. The technique and results are critical for designing multi-stage laser-wakefield accelerators, and generating high-brightness, spatially coherent x-rays.« less

  7. Four-probe measurements with a three-probe scanning tunneling microscope

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

    Salomons, Mark; Martins, Bruno V. C.; Zikovsky, Janik

    2014-04-15

    We present an ultrahigh vacuum (UHV) three-probe scanning tunneling microscope in which each probe is capable of atomic resolution. A UHV JEOL scanning electron microscope aids in the placement of the probes on the sample. The machine also has a field ion microscope to clean, atomically image, and shape the probe tips. The machine uses bare conductive samples and tips with a homebuilt set of pliers for heating and loading. Automated feedback controlled tip-surface contacts allow for electrical stability and reproducibility while also greatly reducing tip and surface damage due to contact formation. The ability to register inter-tip position bymore » imaging of a single surface feature by multiple tips is demonstrated. Four-probe material characterization is achieved by deploying two tips as fixed current probes and the third tip as a movable voltage probe.« less

  8. Four-probe measurements with a three-probe scanning tunneling microscope.

    PubMed

    Salomons, Mark; Martins, Bruno V C; Zikovsky, Janik; Wolkow, Robert A

    2014-04-01

    We present an ultrahigh vacuum (UHV) three-probe scanning tunneling microscope in which each probe is capable of atomic resolution. A UHV JEOL scanning electron microscope aids in the placement of the probes on the sample. The machine also has a field ion microscope to clean, atomically image, and shape the probe tips. The machine uses bare conductive samples and tips with a homebuilt set of pliers for heating and loading. Automated feedback controlled tip-surface contacts allow for electrical stability and reproducibility while also greatly reducing tip and surface damage due to contact formation. The ability to register inter-tip position by imaging of a single surface feature by multiple tips is demonstrated. Four-probe material characterization is achieved by deploying two tips as fixed current probes and the third tip as a movable voltage probe.

  9. Use of cryostat sections from snap-frozen nervous tissue for combining stereological estimates with histological, cellular, or molecular analyses on adjacent sections.

    PubMed

    Schmitz, C; Dafotakis, M; Heinsen, H; Mugrauer, K; Niesel, A; Popken, G J; Stephan, M; Van de Berg, W D; von Hörsten, S; Korr, H

    2000-10-01

    Adequate tissue preparation is essential for both modern stereological and immunohistochemical investigations. However, combining these methodologies in a single study presents a number of obstacles pertaining to optimal histological preparation. Tissue shrinkage and loss of nuclei/nucleoli from the unprotected section surfaces of unembedded tissue used for immunohistochemistry may be problematic with regard to adequate stereological design. In this study, frozen cryostat sections from hippocampal and cerebellar regions of two rat strains and cerebellar and cerebral regions from a human brain were analyzed to determine the potential impact of these factors on estimates of neuron number obtained using the optical disector. Neuronal nuclei and nucleoli were clearly present in thin sections of snap-frozen rat (3 microm) and human (6 microm) tissue, indicating that neuronal nuclei/nucleoli are not unavoidably lost from unprotected section surfaces of unembedded tissue. In order to quantify the potential impact of any nuclear loss, optical fractionator estimates of rat hippocampal pyramidal cells in areas CA1-3 and cerebellar granule and Purkinje cells were made using minimal (1 microm) upper guard zones. Estimates did not differ from data reported previously in the literature. This data indicates that cryostat sections of snap-frozen nervous tissue may successfully be used for estimating total neuronal numbers using optical disectors.

  10. Probing plasma fluorinated graphene via spectromicroscopy.

    PubMed

    Struzzi, C; Scardamaglia, M; Reckinger, N; Sezen, H; Amati, M; Gregoratti, L; Colomer, J-F; Ewels, C; Snyders, R; Bittencourt, C

    2017-11-29

    Plasma fluorination of graphene is studied using a combination of spectroscopy and microscopy techniques, giving insight into the yield and fluorination mechanism for functionalization of supported graphene with both CF 4 and SF 6 gas precursors. Ion acceleration during fluorination is used to probe the effect on grafting functionalities. Adatom clustering, which occurs with CF 4 plasma treatment, is suppressed when higher kinetic energy is supplied to the ions. During SF 6 plasma functionalization, the sulfur atoms tend to bond to bare copper areas instead of affecting the graphene chemistry, except when the kinetic energy of the ions is restricted. Using scanning photoelectron microscopy, with a 100 nm spatial resolution, the chemical bonding environment is evaluated in the fluorinated carbon network at selected regions and the functionalization homogeneity is controlled in individual graphene flakes.

  11. Accelerator system and method of accelerating particles

    NASA Technical Reports Server (NTRS)

    Wirz, Richard E. (Inventor)

    2010-01-01

    An accelerator system and method that utilize dust as the primary mass flux for generating thrust are provided. The accelerator system can include an accelerator capable of operating in a self-neutralizing mode and having a discharge chamber and at least one ionizer capable of charging dust particles. The system can also include a dust particle feeder that is capable of introducing the dust particles into the accelerator. By applying a pulsed positive and negative charge voltage to the accelerator, the charged dust particles can be accelerated thereby generating thrust and neutralizing the accelerator system.

  12. Scattering of accelerated wave packets

    NASA Astrophysics Data System (ADS)

    Longhi, S.; Horsley, S. A. R.; Della Valle, G.

    2018-03-01

    Wave-packet scattering from a stationary potential is significantly modified when the wave packet is subject to an external time-dependent force during the interaction. In the semiclassical limit, wave-packet motion is simply described by Newtonian equations, and the external force can, for example, cancel the potential force, making a potential barrier transparent. Here we consider wave-packet scattering from reflectionless potentials, where in general the potential becomes reflective when probed by an accelerated wave packet. In the particular case of the recently introduced class of complex Kramers-Kronig potentials we show that a broad class of time-dependent forces can be applied without inducing any scattering, while there is a breakdown of the reflectionless property when there is a broadband distribution of initial particle momentum, involving both positive and negative components.

  13. Acceleration Noise Measurements for LISA

    NASA Astrophysics Data System (ADS)

    Schlamminger, Stephan; Gundlach, Jens

    2005-04-01

    The close spacing between the proof mass and the housing in the LISA (Laser Interferometer Space Antenna) spacecraft has been a concern as there may be spurious feeble forces. Such forces may limit the performance of the gravity wave detector at frequencies below 3 mHz and must be studied experimentally. We are performing ultra sensitive torsion balance tests to investigate such effects. Our torsion pendulum and a nearby plate are designed to simulate the LISA proof mass with its adjacent housing surface. We study torque noise on the pendulum as a function of separation between the surfaces. In order to exceed the LISA requirement we are probing the acceleration noise at much closer separations, than those planned for LISA. We have taken data at separations as small as 0.15 mm.

  14. Staging of laser-plasma accelerators

    DOE PAGES

    Steinke, S.; van Tilborg, J.; Benedetti, C.; ...

    2016-05-02

    We present results of an experiment where two laser-plasma-accelerator stages are coupled at a short distance by a plasma mirror. Stable electron beams from the first stage were used to longitudinally probe the dark-current-free, quasi-linear wakefield excited by the laser of the second stage. Changing the arrival time of the electron beam with respect to the second stage laser pulse allowed reconstruction of the temporal wakefield structure, determination of the plasma density, and inference of the length of the electron beam. The first stage electron beam could be focused by an active plasma lens to a spot size smaller thanmore » the transverse wake size at the entrance of the second stage. Furthermore, this permitted electron beam trapping, verified by a 100 MeV energy gain.« less

  15. Unravelling RNA-substrate interactions in a ribozyme-catalysed reaction using fluorescent turn-on probes.

    PubMed

    Gaffarogullari, Ece Cazibe; Greulich, Peter; Kobitski, Andrei Yu; Nierth, Alexander; Nienhaus, G Ulrich; Jäschke, Andres

    2015-04-07

    The Diels-Alder reaction is one of the most important C-C bond-forming reactions in organic chemistry, and much effort has been devoted to controlling its enantio- and diastereoselectivity. The Diels-Alderase ribozyme (DAse) catalyses the reaction between anthracene dienes and maleimide dienophiles with multiple-turnover, stereoselectivity, and up to 1100-fold rate acceleration. Here, a new generation of anthracene-BODIPY-based fluorescent probes was developed to monitor catalysis by the DAse. The brightness of these probes increases up to 93-fold upon reaction with N-pentylmaleimide (NPM), making these useful tools for investigating the stereochemistry of the ribozyme-catalysed reaction. With these probes, we observed that the DAse catalyses the reaction with >91% de and >99% ee. The stereochemistry of the major product was determined unambiguously by rotating-frame nuclear Overhauser NMR spectroscopy (ROESY-NMR) and is in agreement with crystallographic structure information. The pronounced fluorescence change of the probes furthermore allowed a complete kinetic analysis, which revealed an ordered bi uni type reaction mechanism, with the dienophile binding first. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Frequency-Domain Streak Camera and Tomography for Ultrafast Imaging of Evolving and Channeled Plasma Accelerator Structures

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

    Li Zhengyan; Zgadzaj, Rafal; Wang Xiaoming

    2010-11-04

    We demonstrate a prototype Frequency Domain Streak Camera (FDSC) that can capture the picosecond time evolution of the plasma accelerator structure in a single shot. In our prototype Frequency-Domain Streak Camera, a probe pulse propagates obliquely to a sub-picosecond pump pulse that creates an evolving nonlinear index 'bubble' in fused silica glass, supplementing a conventional Frequency Domain Holographic (FDH) probe-reference pair that co-propagates with the 'bubble'. Frequency Domain Tomography (FDT) generalizes Frequency-Domain Streak Camera by probing the 'bubble' from multiple angles and reconstructing its morphology and evolution using algorithms similar to those used in medical CAT scans. Multiplexing methods (Temporalmore » Multiplexing and Angular Multiplexing) improve data storage and processing capability, demonstrating a compact Frequency Domain Tomography system with a single spectrometer.« less

  17. Thermo-Physics Technical Note No. 60: thermal analysis of SNAP 10A reactor core during atmospheric reentry and resulting core disintegration and fuel element separation

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

    Mouradian, E.M.

    1966-02-16

    A thermal analysis is carried out to determine the temperature distribution throughout a SNAP 10A reactor core, particularly in the vicinity of the grid plates, during atmospheric reentry. The transient temperatue distribution of the grid plate indicates when sufficient melting occurs so that fuel elements are free to be released and continue their descent individually.

  18. Microfluidics for Positron Emission Tomography (PET) Imaging Probe Development

    PubMed Central

    Wang, Ming-Wei; Lin, Wei-Yu; Liu, Kan; Masterman-Smith, Michael; Shen, Clifton Kwang-Fu

    2012-01-01

    Due to increased needs for Positron Emission Tomography (PET) scanning, high demands for a wide variety of radiolabeled compounds will have to be met by exploiting novel radiochemistry and engineering technologies to improve the production and development of PET probes. The application of microfluidic reactors to perform radiosyntheses is currently attracting a great deal of interest because of their potential to deliver many advantages over conventional labeling systems. Microfluidic-based radiochemistry can lead to the use of smaller quantities of precursors, accelerated reaction rates and easier purification processes with greater yield and higher specific activity of desired probes. Several ‘proof-of-principle’ examples, along with basics of device architecture and operation, and potential limitations of each design are discussed here. Along with the concept of radioisotope distribution from centralized cyclotron facilities to individual imaging centers and laboratories (“decentralized model”), an easy-to-use, standalone, flexible, fully-automated radiochemical microfluidic platform can open up to simpler and more cost-effective procedures for molecular imaging using PET. PMID:20643021

  19. Traversing probe system

    DOEpatents

    Mashburn, Douglas N.; Stevens, Richard H.; Woodall, Harold C.

    1977-01-01

    This invention comprises a rotatable annular probe-positioner which carries at least one radially disposed sensing probe, such as a Pitot tube having a right-angled tip. The positioner can be coaxially and rotatably mounted within a compressor casing or the like and then actuated to orient the sensing probe as required to make measurements at selected stations in the annulus between the positioner and compressor casing. The positioner can be actuated to (a) selectively move the probe along its own axis, (b) adjust the yaw angle of the right-angled probe tip, and (c) revolve the probe about the axis common to the positioner and casing. A cam plate engages a cam-follower portion of the probe and normally rotates with the positioner. The positioner includes a first-motor-driven ring gear which effects slidable movement of the probe by rotating the positioner at a time when an external pneumatic cylinder is actuated to engage the cam plate and hold it stationary. When the pneumatic cylinder is not actuated, this ring gear can be driven to revolve the positioner and thus the probe to a desired circumferential location about the above-mentioned common axis. A second motor-driven ring gear included in the positioner can be driven to rotate the probe about its axis, thus adjusting the yaw angle of the probe tip. The positioner can be used in highly corrosive atmosphere, such as gaseous uranium hexafluoride.

  20. ENVIRONMENTAL CONTAMINATION AND DEVELOPMENTAL ABNORMALITIES IN EGGS AND HATCHLINGS OF THE COMMON SNAPPING TURTLE (CHELYDRA SERPENTINA SERPENTINA) FROM THE GREAT LAKES-ST. LAWRENCE RIVER BASIN (1989-91). (R827102)

    EPA Science Inventory

    Abstract

    During 1989-91, we assessed developmental abnormalities in embryos and hatchlings from eggs of the common snapping turtle (Chelydra serpentina serpentina). Eggs were collected and artificially incubated from eight sites in Ontario, Canada and Akwesasne/...