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Sample records for deciphering formation processes

  1. Deciphering the influence of the thermal processes on the early passive margins formation

    NASA Astrophysics Data System (ADS)

    Bousquet, Romain; Nalpas, Thierry; Ballard, Jean-François; Ringenbach, Jean-Claude; Chelalou, Roman; Clerc, Camille

    2015-04-01

    Many large-scale dynamic processes, from continental rifting to plate subduction, are intimately linked to metamorphic reactions. This close relation between geodynamic processes and metamorphic reactions is, in spite of appearances, yet poorly understood. For example, during extension processes, rocks will be exposed to important temperature, pressures and stress changes. Meanwhile less attention has been paid to other important aspects of the metamorphic processes. When reacting rocks expand and contract, density and volume changes will set up in the surrounding material. While several tectonic models are proposed to explain the formation of extensive basins and passive margins ( simple shear detachment mantle exhumation .... ) a single thermal model (McKenzie , 1978), as a dogma, is used to understanding and modeling the formation and evolution of sedimentary basins . This model is based on the assumption that the extension is only by pure shear and it is instantaneous. Under this approach, the sedimentary deposits occur in two stages. i) A short step , 1 to 10 Ma , controlled by tectonics. ii) A longer step , at least 50 Ma as a result of the thermal evolution of the lithosphere.
However, most stratigraphic data indicate that less thermal model can account for documented vertical movements. The study of the thermal evolution , coupled with other tectonic models , and its consequences have never been studied in detail , although the differences may be significant and it is clear that the petrological changes associated with changes in temperature conditions , influence changes reliefs.
In addition, it seems that the relationship between basin formation and thermal evolution is not always the same:
- Sometimes the temperature rise above 50 to 100 Ma tectonic extension. In the Alps, a significant rise in geothermal gradient Permo -Triassic followed by a "cold" extension , leading to the opening of the Ligurian- Piedmont ocean, from the Middle Jurassic .

  2. Deciphering site formation processes through soil micromorphology at Contrebandiers Cave, Morocco.

    PubMed

    Aldeias, Vera; Goldberg, Paul; Dibble, Harold L; El-Hajraoui, Mohamed

    2014-04-01

    Contrebandiers Cave preserves a Late Pleistocene sequence containing Middle Stone Age (MSA) so-called Maghrebian Mousterian and Aterian occupations, spanning from ∼126 to 95 ka (thousands of years ago), followed by spatially restricted Iberomaurusian industries. Micromorphological analyses, complemented by instrumental mineralogical identification and fabric orientation, allowed for the reconstruction of the main site formation processes at the site. Initial deposition is characterized by local reworking of marine shelly sands dating to Marine Isotopic Stage 5e (MIS5e). The subsequent stratification reveals sedimentary dynamics predominantly associated with gravity-driven inputs and contributions from weathering of the encasing bedrock, at the same time that anthropogenic sediments were being accumulated. The allochthonous components reflect soil degradation and vegetation changes around the cave during the last interglacial. Human occupations seems to be somewhat ephemeral in nature, with some stratigraphic units apparently lacking archaeological components, while in others the human-associated deposits (e.g., burned bones, charcoal, and ashes) can be substantial. Ephemeral breaks in sedimentation and/or erosion followed by stabilization are mainly discernible microscopically by the presence of phosphatic-rich laminae interpreted as short-lived surfaces, peaks of increased humidity and colonization by plants. More substantial erosion affects the uppermost Aterian layers, presumably due to localized reconfigurations of the cave's roof. The subsequent Iberomaurusian deposits are not in their primary position and are associated with well-sorted silts of aeolian origin. While the effects of chemical diagenesis are limited throughout the whole stratigraphic sequence, physical bioturbation (e.g., by wasps, rodents, and earthworms) is more pervasive and leads to localized movement of the original sedimentary particles.

  3. Space Weathering of Apollo 16 Sample 62255: Lunar Rocks as Witness Plates for Deciphering Regolith Formation Processes

    NASA Technical Reports Server (NTRS)

    Wentworth, S. J.; McKay, D. S.; Keller, L. P.

    2004-01-01

    Space weathering, or alteration that occurs at the surfaces of materials exposed directly to space, has been one of the primary areas of focus of lunar studies for the past several years. It is caused by processes such as micrometeorite impacts and solar wind bombardment, and effects can include microcraters, spall zones, and vapor deposits. Much of the recent work on space weathering has been concentrated on nanoscale features, especially the amorphous rims commonly found on individual lunar soil grains. The rims typically contain nanophase Fe metal globules, which, along with Fe metal globules in agglutinates, have a profound effect on optical properties of lunar soils. The nanophase metallic iron globules cause the characteristic optical changes (reddening and darkening) found in mature lunar soils.

  4. Deciphering Piperidine Formation in Polyketide-Derived Indolizidines Reveals a Thioester Reduction, Transamination, and Unusual Imine Reduction Process.

    PubMed

    Peng, Haidong; Wei, Erman; Wang, Jiali; Zhang, Yanan; Cheng, Lin; Ma, Hongmin; Deng, Zixin; Qu, Xudong

    2016-12-16

    Piperidine and indolizidine are two basic units of alkaloids that are frequently observed in natural and synthetic compounds. Their biosynthesis in natural products is highly conserved and mostly derived from the incorporation of lysine cyclization products. Through in vitro reconstitution, we herein identified a novel pathway involving a group of polyketide-derived indolizidines, which comprises the processes of tandem two-electron thioester reduction, transamination, and imine reduction to convert acyl carrier protein (ACP)-tethered polyketide chains into the piperidine moieties of their indolizidine scaffolds. The enzymes that catalyze the imine reduction are distinct from previous known imine reductases, which have a fold of acyl-CoA dehydrogenase but do not require flavin for reduction. Our results not only provide a new way for the biosynthesis of the basic units of alkaloids but also show a novel class of imine reductases that may benefit the fields of biocatalysis and biomanufacturing.

  5. Deciphering formation processes of banded iron formations from the Transvaal and the Hamersley successions by combined Si and Fe isotope analysis using UV femtosecond laser ablation

    NASA Astrophysics Data System (ADS)

    Steinhoefel, Grit; von Blanckenburg, Friedhelm; Horn, Ingo; Konhauser, Kurt O.; Beukes, Nicolas J.; Gutzmer, Jens

    2010-05-01

    To investigate the genesis of BIFs, we have determined the Fe and Si isotope composition of coexisting mineral phases in samples from the ˜2.5 billion year old Kuruman Iron Formation (Transvaal Supergroup, South Africa) and Dales Gorges Member of the Brockman Iron Formation (Hamersley Group, Australia) by UV femtosecond laser ablation coupled to a MC-ICP-MS. Chert yields a total range of δ 30Si between -1.3‰ and -0.8‰, but the Si isotope compositions are uniform in each core section examined. This uniformity suggests that Si precipitated from well-mixed seawater far removed from its sources such as hydrothermal vents or continental drainage. The Fe isotope composition of Fe-bearing mineral phases is much more heterogeneous compared to Si with δ 56Fe values of -2.2‰ to 0‰. This heterogeneity is likely due to variable degrees of partial Fe(II) oxidation in surface waters, precipitation of different mineral phases and post-depositional Fe redistribution. Magnetite exhibits negative δ 56Fe values, which can be attributed to a variety of diagenetic pathways: the light Fe isotope composition was inherited from the Fe(III) precursor, heavy Fe(II) was lost by abiotic reduction of the Fe(III) precursor or light Fe(II) was gained from external fluids. Micrometer-scale heterogeneities of δ 56Fe in Fe oxides are attributed to variable degrees of Fe(II) oxidation or to isotope exchange upon Fe(II) adsorption within the water column and to Fe redistribution during diagenesis. Diagenetic Fe(III) reduction caused by oxidation of organic matter and Fe redistribution is supported by the C isotope composition of a carbonate-rich sample containing primary siderite. These carbonates yield δ 13C values of ˜-10‰, which hints at a mixed carbon source in the seawater of both organic and inorganic carbon. The ancient seawater composition is estimated to have a minimum range in δ 56Fe of -0.8‰ to 0‰, assuming that hematite and siderite have preserved their primary Fe

  6. Deciphering Dynamical Patterns of Growth Processes

    ERIC Educational Resources Information Center

    Kolakowska, A.

    2009-01-01

    Large systems of statistical physics often display properties that are independent of particulars that characterize their microscopic components. Universal dynamical patterns are manifested by the presence of scaling laws, which provides a common insight into governing physics of processes as vastly diverse as, e.g., growth of geological…

  7. Deciphering the pathogenesis of tendinopathy: a three-stages process

    PubMed Central

    2010-01-01

    Our understanding of the pathogenesis of "tendinopathy" is based on fragmented evidences like pieces of a jigsaw puzzle. We propose a "failed healing theory" to knit these fragments together, which can explain previous observations. We also propose that albeit "overuse injury" and other insidious "micro trauma" may well be primary triggers of the process, "tendinopathy" is not an "overuse injury" per se. The typical clinical, histological and biochemical presentation relates to a localized chronic pain condition which may lead to tendon rupture, the latter attributed to mechanical weakness. Characterization of pathological "tendinotic" tissues revealed coexistence of collagenolytic injuries and an active healing process, focal hypervascularity and tissue metaplasia. These observations suggest a failed healing process as response to a triggering injury. The pathogenesis of tendinopathy can be described as a three stage process: injury, failed healing and clinical presentation. It is likely that some of these "initial injuries" heal well and we speculate that predisposing intrinsic or extrinsic factors may be involved. The injury stage involves a progressive collagenolytic tendon injury. The failed healing stage mainly refers to prolonged activation and failed resolution of the normal healing process. Finally, the matrix disturbances, increased focal vascularity and abnormal cytokine profiles contribute to the clinical presentations of chronic tendon pain or rupture. With this integrative pathogenesis theory, we can relate the known manifestations of tendinopathy and point to the "missing links". This model may guide future research on tendinopathy, until we could ultimately decipher the complete pathogenesis process and provide better treatments. PMID:21144004

  8. 17Oexcess in meteoric water: as a new isotopic parameter to decipher water cycle processes

    NASA Astrophysics Data System (ADS)

    Landais, A.; Guillevic, M.; Steen-Larsen, H.; Vimeux, F.; Bouygues, A.; Falourd, S.; Risi, C. M.; Bony, S.

    2009-12-01

    Classical water stable isotopes (dD and d18O) have been used for more than 50 years with the aim to understand the links between water cycle and climate. They provide information on either temperature or precipitation changes depending on the latitudes. Their combination, in the so-called d-excess, brings some information on climatic conditions occurring during non equilibrium processes along air masses histories (evaporation over the Oceans, reevaporation of droplets in convective systems, continental recycling or ice crystals formation). Recently, the possibility to measure with high precision d17O in water has enabled to introduce a new parameter, 17Oexcess, resulting from the combination of d18O and d17O. According to both observations and modeling works, this new isotopic parameter is able to decipher some of the non equilibrium processes: when measured in ice core, it is expected to be a more direct tracer of relative humidity of the oceanic evaporative regions than d-excess. In order to better understand what controls this new parameter as well as to extract the maximum climatic information from the combination of 17Oexcess and d-excess, we present different original studies combining these two parameters in several key regions. First, data collected in Niger, West Africa, at scales ranging from the convective system to the seasonal cycle confirm the strong influence of relative humidity on 17Oexcess through the rain reevaporation process. Second, seasonal cycles in the Zongo Valley (Tropical Bolivia) suggest that rain recycling along air masses trajectories have different signatures on d-excess and 17Oexcess leading to decipher the different processes. Third, we study how local processes (precipitation, sublimation) in polar region (Greenland) can affect 17Oexcess archived in ice core with respect to d-excess records through (1) isotopic measurements of vapor versus precipitation collected at the NEEM station and (2) seasonal cycles measured from snow pits.

  9. Geochemistry of the Neoproterozoic Johnnie Formation and Stirling Quartzite, southern Nopah Range, California: Deciphering the roles of climate, tectonics, and sedimentary process in reconstructing the early evolution of a rifted continental margin

    NASA Astrophysics Data System (ADS)

    Schoenborn, William A.

    The Neoproterozoic Stirling Quartzite and Johnnie Formation in the southern Nopah Range, southeastern California, comprise a thick sequence of predominantly siliciclastic sediment that is exposed along the Cordilleran margin. Located above the syn-rift Kingston Peak Formation, they mark the early deposits of passive margin sedimentation during the breakup of the Rodinia supercontinent. Disagreement exists between field-based observations and subsidence modeling as to whether these units represent rift or passive margin deposition. In this study, major-, trace-, and rare earth--element (REE) geochemistry, and U-Pb detrital zircon geochronology are used to determine their provenance, paleoclimatic information, and, consequently their paleotectonic setting. Geochemical and petrologic evidence confirm that Johnnie Formation mudstones and sandstones were the initial siliciclastic deposits laid along the Cordilleran Laurentian margin following the Neoproterozoic break-up of Rodinia. Johnnie Formation sediment has corrected CIA values between 63 and 83, and likely higher, which suggests moderate to intense weathering of the source. Modeling suggests the unweathered source likely possessed a composition of a 90% granodiorite + 10% high-K granite. This mixture balances petrographic observations, major element geochemistry, and the REE: (La/Sm)N = 4.19 +/- 1.26, (Gd/Yb)N = 1.34 +/- 0.38, Eu/Eu* = 0.63 +/- 0.09 and (La/Yb)N = 9.55 +/- 2.27. The hypothesis of a primary tectonic control on sediment composition (i.e. rift-basin deposition) is rejected because Johnnie Formation sediments largely lack lithic fragments that are indicative of derivation from a source area with rugged topography. Feldspars are distributed unevenly in finer grained sediments. Observed fluctuations in feldspar content of sediments from the lower to upper Johnnie Formation are attributed to increased abrasion and hydrodynamic sorting, which differentially segregated feldspars into finer grained

  10. Quantitative Proteomic and Phosphoproteomic Approaches for Deciphering the Signaling Pathway for Tension Wood Formation in Poplar.

    PubMed

    Mauriat, Mélanie; Leplé, Jean-Charles; Claverol, Stéphane; Bartholomé, Jérôme; Negroni, Luc; Richet, Nicolas; Lalanne, Céline; Bonneu, Marc; Coutand, Catherine; Plomion, Christophe

    2015-08-07

    Trees adjust their growth following forced changes in orientation to re-establish a vertical position. In angiosperms, this adjustment involves the differential regulation of vascular cambial activity between the lower (opposite wood) and upper (tension wood) sides of the leaning stem. We investigated the molecular mechanisms leading to the formation of differential wood types through a quantitative proteomic and phosphoproteomic analysis on poplar subjected to a gravitropic stimulus. We identified and quantified 675 phosphopeptides, corresponding to 468 phosphoproteins, and 3 763 nonphosphorylated peptides, corresponding to 1 155 proteins, in the differentiating xylem of straight-growing trees (control) and trees subjected to a gravitational stimulus during 8 weeks. About 1% of the peptides were specific to a wood type (straight, opposite, or tension wood). Proteins quantified in more than one type of wood were more numerous: a mixed linear model showed 389 phosphopeptides and 556 proteins to differ in abundance between tension wood and opposite wood. Twenty-one percent of the phosphoproteins identified here were described in their phosphorylated form for the first time. Our analyses revealed remarkable developmental molecular plasticity, with wood type-specific phosphorylation events, and highlighted the involvement of different proteins in the biosynthesis of cell wall components during the formation of the three types of wood.

  11. Developmental integration in a functional unit: deciphering processes from adult dental morphology.

    PubMed

    Labonne, Gaëlle; Navarro, Nicolas; Laffont, Rémi; Chateau-Smith, Carmela; Montuire, Sophie

    2014-01-01

    The evolution of mammalian dentition is constrained by functional necessity and by the non-independence of morphological structures. Efficient chewing implies coherent tooth coordination from development to motion, involving covariation patterns (integration) within dental parts. Using geometric morphometrics, we investigate the modular organization of the highly derived vole dentition. Integration patterns between and within the upper and lower molar rows are analyzed to identify potential modules and their origins (functional and developmental). Results support an integrated adult dentition pattern for both developmental and functional aspects. The integration patterns between opposing molar pairs suggest a transient role for the second upper and lower molars during the chewing motion. Upper and lower molar rows form coherent units but the relative integration of molar pairs is in contradiction with existing developmental models. Emphasis on the first three cusps to grow leads to a very different integration pattern, which would be congruent with developmental models. The early developmental architecture of traits is masked by later stages of growth, but may still be deciphered from the adult phenotype, if careful attention is paid to relevant features.

  12. Capturing extracellular matrix properties in vitro: Microengineering materials to decipher cell and tissue level processes

    PubMed Central

    Abdeen, Amr A; Lee, Junmin

    2016-01-01

    Rapid advances in biology have led to the establishment of new fields with tremendous translational potential including regenerative medicine and immunoengineering. One commonality to these fields is the need to extract cells for manipulation in vitro; however, results obtained in laboratory cell culture will often differ widely from observations made in vivo. To more closely emulate native cell biology in the laboratory, designer engineered environments have proved a successful methodology to decipher the properties of the extracellular matrix that govern cellular decision making. Here, we present an overview of matrix properties that affect cell behavior, strategies for recapitulating important parameters in vitro, and examples of how these properties can affect cell and tissue level processes, with emphasis on leveraging these tools for immunoengineering. PMID:27075930

  13. Prominence Formation Processes

    NASA Astrophysics Data System (ADS)

    Welsch, B. T.; DeVore, C. R.; Antiochos, S. K.

    2005-01-01

    Martens and Zwaan (ApJ v. 558 872) have proposed a prominence/ filament formation model in which differential rotation drives reconnection between two initially unconnected active regions to form helical field lines that support mass and are held down by overlying field. Using an MHD solver with adaptive refinement we simulated this process by imposing a shear flow meant to mimic differential rotation on two bipolar flux distributions meant to mimic distinct active regions. In some runs the flux systems are initially potential while in others they have been twisted by footpoint rotation to inject helicity prior to imposing the shear flow. The resulting structures are studied to understand the role of helicity in the formation of prominence-like structures.

  14. Deciphering the Temporal Link between Pain and Sleep in a Heterogeneous Chronic Pain Patient Sample: A Multilevel Daily Process Study

    PubMed Central

    Tang, Nicole K.Y.; Goodchild, Claire E.; Sanborn, Adam N.; Howard, Jonathan; Salkovskis, Paul M.

    2012-01-01

    Objectives: Because insomnia is a common comorbidity of chronic pain, scientific and clinical interest in the relationship of pain and sleep has surged in recent years. Although experimental studies suggest a sleep-interfering property of pain and a pain-enhancing effect of sleep deprivation/fragmentation, the temporal association between pain and sleep as experienced by patients is less understood. The current study was conducted to examine the influence of presleep pain on subsequent sleep and sleep on pain reports the next day, taking into consideration other related psychophysiologic variables such as mood and arousal. Design: A daily process study, involving participants to monitor their pain, sleep, mood, and presleep arousal for 1 wk. Multilevel modeling was used to analyze the data. Setting: In the patients' natural living and sleeping environment. Patients: One hundred nineteen patients (73.9% female, mean age = 46 years) with chronic pain and concomitant insomnia. Measurement: An electronic diary was used to record patients' self-reported sleep quality/efficiency and ratings of pain, mood, and arousal at different times of the day; actigraphy was also used to provide estimates of sleep efficiency. Results: Results indicated that presleep pain was not a reliable predictor of subsequent sleep. Instead, sleep was better predicted by presleep cognitive arousal. Although sleep quality was a consistent predictor of pain the next day, the pain-relieving effect of sleep was only evident during the first half of the day. Conclusions: These findings challenge the often-assumed reciprocal relationship between pain and sleep and call for a diversification in thinking of the daily interaction of these 2 processes. Citation: Tang NKY; Goodchild CE; Sanborn AN; Howard J; Salkovskis PM. Deciphering the temporal link between pain and sleep in a heterogeneous chronic pain patient sample: a multilevel daily process study. SLEEP 2012;35(5):675-687. PMID:22547894

  15. Deciphering the photochemical mechanisms describing the UV-induced processes occurring in solvated guanine monophosphate

    PubMed Central

    Altavilla, Salvatore F.; Segarra-Martí, Javier; Nenov, Artur; Conti, Irene; Rivalta, Ivan; Garavelli, Marco

    2015-01-01

    The photophysics and photochemistry of water-solvated guanine monophosphate (GMP) are here characterized by means of a multireference quantum-chemical/molecular mechanics theoretical approach (CASPT2//CASSCF/AMBER) in order to elucidate the main photo-processes occurring upon UV-light irradiation. The effect of the solvent and of the phosphate group on the energetics and structural features of this system are evaluated for the first time employing high-level ab initio methods and thoroughly compared to those in vacuo previously reported in the literature and to the experimental evidence to assess to which extent they influence the photoinduced mechanisms. Solvated electronic excitation energies of solvated GMP at the Franck-Condon (FC) region show a red shift for the ππ* La and Lb states, whereas the energy of the oxygen lone-pair nπ* state is blue-shifted. The main photoinduced decay route is promoted through a ring-puckering motion along the bright lowest-lying La state toward a conical intersection (CI) with the ground state, involving a very shallow stationary point along the minimum energy pathway in contrast to the barrierless profile found in gas-phase, the point being placed at the end of the minimum energy path (MEP) thus endorsing its ultrafast deactivation in accordance with time-resolved transient and photoelectron spectroscopy experiments. The role of the nπ* state in the solvated system is severely diminished as the crossings with the initially populated La state and also with the Lb state are placed too high energetically to partake prominently in the deactivation photo-process. The proposed mechanism present in solvated and in vacuo DNA/RNA chromophores validates the intrinsic photostability mechanism through CI-mediated non-radiative processes accompanying the bright excited-state population toward the ground state and subsequent relaxation back to the FC region. PMID:25941671

  16. Deciphering the photochemical mechanisms describing the UV-induced processes occurring in solvated guanine monophosphate

    NASA Astrophysics Data System (ADS)

    Altavilla, Salvatore; Segarra-Martí, Javier; Nenov, Artur; Conti, Irene; Rivalta, Ivan; Garavelli, Marco

    2015-04-01

    The photophysics and photochemistry of water-solvated guanine monophosphate (GMP) are here characterized by means of a multireference quantum-chemical/molecular mechanics theoretical approach (CASPT2//CASSCF/AMBER) in order to elucidate the main photo-processes occurring upon UV-light irradiation. The effect of the solvent and of the phosphate group on the energetics and structural features of this system are evaluated for the first time employing high-level ab initio methods and thoroughly compared to those in vacuo previously reported in the literature and to the experimental evidence to assess to which extent they influence the photoinduced mechanisms. Solvated electronic excitation energies of solvated GMP at the Franck-Condon (FC) region show a red shift for the ππ* La and Lb states, whereas the energy of the oxygen lone-pair nπ* state is blue-shifted. The main photoinduced decay route is promoted through a ring-puckering motion along the bright lowest-lying La state towards a conical intersection (CI) with the ground state, involving a very shallow stationary point along the minimum energy pathway in contrast to the barrierless profile found in gas-phase, the point being placed at the end of the minimum energy path (MEP) thus endorsing its ultrafast deactivation in accordance with time-resolved transient and photoelectron spectroscopy experiments. The role of the nπ* state in the solvated system is severely diminished as the crossings with the initially populated La state and also with the Lb state are placed too high energetically to partake prominently in the deactivation photo-process. The proposed mechanism present in solvated and in vacuo DNA/RNA chromophores validates the intrinsic photostability mechanism through CI-mediated non-radiative processes accompanying the bright excited-state population towards the ground state and subsequent relaxation back to the FC region.

  17. What Controls the Sizes and Shapes of Volcanic Ash? Integrating Morphological, Textural and Geochemical Ash Properties to Decipher Eruptive Processes

    NASA Astrophysics Data System (ADS)

    Liu, E. J.; Cashman, K. V.; Rust, A.

    2015-12-01

    Volcanic ash particles encompass a diverse spectrum of shapes as a consequence of differences in the magma properties and the magma ascent and eruption conditions. We show how the quantitative analysis of ash particle shapes can be a valuable tool for deciphering magma fragmentation and transport processes. Importantly, integrating morphological data with ash texture (e.g. bubble and crystal sizes) and dissolved volatile data provides valuable insights into the physical and chemical controls on the resulting ash deposit. To explore the influence of magma-water interaction (MWI) on fine ash generation, we apply this multi-component characterisation to tephra from the 2500BC Hverfjall Fires, Iceland. Here, coeval fissure vents spanned sub-aerial to shallow lacustrine environments. Differences in the size and morphology of pyroclasts thus reflect fragmentation mechanisms under different near-surface conditions. Using shape parameters sensitive to both particle roughness and internal vesicularity, we quantify the relative proportions of dense fragments, bubble shards, and vesicular grains from 2-D SEM images. We show that componentry (and particle morphology) varies as a function of grain size, and that this variation can be related back to the bubble size distribution. Although both magmatic and hydromagmatic deposits exhibit similar component assemblages, they differ in how these assemblages change with grain size. These results highlight the benefits of characterising ash deposits over a wide range of grain sizes, and caution against inferring fragmentation mechanism from a narrow grain size range. Elevated matrix glass S concentrations in hydromagmatic ash (600-1500 ppm) compared to those in magmatic ash and scoria lapilli (200-500 ppm) indicate interrupted vesiculation. In contrast to the subaerial 'dry' deposits, fragmentation during MWI likely occurred over a greater range of depths with quench rates sufficient to prevent post-fragmentation degassing. High

  18. Deciphering the sedimentological imprint of paleoseismic events: an example from the Aptian Codó Formation, northern Brazil

    NASA Astrophysics Data System (ADS)

    Rossetti, D. F.; Góes, A. M.

    2000-09-01

    A stratigraphic horizon bearing several styles of soft-sediment structures occurs sandwiched within entirely undisturbed deposits in the lacustrine Codó Formation (Aptian) located in the eastern part of the Grajaú Basin, northern Brazil. These deposits show a variety of sedimentary features distinguished according to their deformation style as follows (from bottom to top): (a) Zone 1, consisting of widespread molar-tooth structures (i.e. fine-grained spar-filled cracks) that are interconnected with small-scale faults, fissures and stylolites inclined at a high angle to bedding; (b) Zone 2, represented by complex convolute folds with lateral gradation of smooth synclines and anticlines into isoclinic folds and internal layers that retain the normal bedding features, recumbent folds, "nappe" folds with associated thrust faults, pseudonodules, and mound-and-sag structures; (c) Zone 3, consisting of normal faults and fissures that are vertical to near vertical, show ragged morphology with small delicate peaks, taper both downward and upward after a few centimeters, and are associated with large (up to 2.5 m long) collapsed boulders; and (d) Zone 4, characterized by shales with irregular convolute folds. These deformation zones are interpreted to reflect sediment rheology and alternating periods of sediment accumulation and deformation under the influence of synsedimentary seismic events, as suggested mostly by: (1) occurrence between undeformed deposits; (2) lateral correlation for several kilometers of distance; (3) similarity with other features formed in areas affected by seismic activity; (4) presence of structures attesting to sediment deformation in an unconsolidated to semi-consolidated state; and (5) complex association of brittle and ductile deformation structures. Hence, Zone 1 records small scale cracking and faulting of early-cemented, cohesive deposits. Zone 2 is dominated by ductile deformation structures formed on water-saturated, unconsolidated

  19. The Multifaceted Planetesimal Formation Process

    NASA Astrophysics Data System (ADS)

    Johansen, A.; Blum, J.; Tanaka, H.; Ormel, C.; Bizzarro, M.; Rickman, H.

    Accumulation of dust and ice particles into planetesimals is an important step in the planet formation process. Planetesimals are the seeds of both terrestrial planets and the solid cores of gas and ice giants forming by core accretion. Leftover planetesimals in the form of asteroids, transneptunian objects, and comets provide a unique record of the physical conditions in the solar nebula. Debris from planetesimal collisions around other stars signposts that the planetesimal formation process, and hence planet formation, is ubiquitous in the Galaxy. The planetesimal formation stage extends from micrometer-sized dust and ice to bodies that can undergo runaway accretion. The latter ranges in size from 1 km to 1000 km, dependent on the planetesimal eccentricity excited by turbulent gas density fluctuations. Particles face many barriers during this growth, arising mainly from inefficient sticking, fragmentation, and radial drift. Two promising growth pathways are mass transfer, where small aggregates transfer up to 50% of their mass in high-speed collisions with much larger targets, and fluffy growth, where aggregate cross sections and sticking probabilities are enhanced by a low internal density. A wide range of particle sizes, from 1 mm to 10 m, concentrate in the turbulent gas flow. Overdense filaments fragment gravitationally into bound particle clumps, with most mass entering planetesimals of contracted radii from 100 km to 500 km, depending on local disk properties. We propose a hybrid model for planetesimal formation where particle growth starts unaided by self-gravity but later proceeds inside gravitationally collapsing pebble clumps to form planetesimals with a wide range of sizes.

  20. Rapid gas hydrate formation process

    DOEpatents

    Brown, Thomas D.; Taylor, Charles E.; Unione, Alfred J.

    2013-01-15

    The disclosure provides a method and apparatus for forming gas hydrates from a two-phase mixture of water and a hydrate forming gas. The two-phase mixture is created in a mixing zone which may be wholly included within the body of a spray nozzle. The two-phase mixture is subsequently sprayed into a reaction zone, where the reaction zone is under pressure and temperature conditions suitable for formation of the gas hydrate. The reaction zone pressure is less than the mixing zone pressure so that expansion of the hydrate-forming gas in the mixture provides a degree of cooling by the Joule-Thompson effect and provides more intimate mixing between the water and the hydrate-forming gas. The result of the process is the formation of gas hydrates continuously and with a greatly reduced induction time. An apparatus for conduct of the method is further provided.

  1. Deciphering Kepler's Planetary Systems

    NASA Astrophysics Data System (ADS)

    Lithwick, Yoram

    The theory for how planetary systems form and achieve their final configuration remains highly uncertain. Until now, theories could only be tested against a single system -- the solar system. The Kepler mission, with its abundance of planetary systems, will likely prove to be a Rosetta stone. However, much remains to be deciphered. To help realize the potential of the Kepler mission, we propose to pursue the complementary tasks of characterizing the properties of the Kepler systems and developing theories to explain these properties: 1) Characterizing Kepler systems. We will characterize these planets using the transit-time-variation (TTV) signatures obtained by the mission. We have recently derived a simple expression for the TTV, and used it to derive the masses and eccentricities of a couple dozen Kepler planets. We will extend that work by applying it to many more planets, and by deriving higher-order TTV effects that will allow us to obtain more accurate measurements by breaking degeneracies. We will also use the TTV signals, as well as other observables, to infer the intrinsic orbital architecture of Kepler planets. This will form the basis for the following study. 2) Assembling Kepler systems. Informed by our above analysis, we will try to uncover how the Kepler planets were assembled onto their current orbits. Our recent work on the resonant repulsion mechanism suggests that the final assembly was shaped by a dissipative process, and we will explore that mechanism further. We will also run simulations to test the conjecture that planetesimals were the dissipative agent responsible for final assembly -- just as they are thought to be responsible for the assembly of the planets in the outer solar system

  2. Processes and problems in secondary star formation

    SciTech Connect

    Klein, R.I.; Whitaker, R.W.; Sandford M.T. II

    1984-03-01

    Recent developments relating the conditions in molecular clouds to star formation triggered by a prior stellar generation are reviewed. Primary processes are those that lead to the formation of a first stellar generation. The secondary processes that produce stars in response to effects caused by existing stars are compared and evaluated in terms of the observational data presently available. We discuss the role of turbulence to produce clumpy cloud structures and introduce new work on colliding inter-cloud gas flows leading to non-linear inhomogeneous cloud structures in an intially smooth cloud. This clumpy morphology has important consequences for secondary formation. The triggering processes of supernovae, stellar winds, and H II regions are discussed with emphasis on the consequences for radiation driven implosion as a promising secondary star formation mechanism. Detailed two-dimensional, radiation-hydrodynamic calculations of radiation driven implosion are discussed. This mechanism is shown to be highly efficient in synchronizing the formation of new stars in congruent to 1-3 x 10/sup 4/ years and could account for the recent evidence for new massive star formation in several UCHII regions. It is concluded that, while no single theory adequately explains the variety of star formation observed, a uniform description of star formation is likely to involve several secondary processes. Advances in the theory of star formation will require multiple dimensional calculations of coupled processes. The important non-linear interactions include hydrodynamics, radiation transport, and magnetic fields.

  3. On the formation process of charged clusters

    NASA Astrophysics Data System (ADS)

    Wang, Youmei; Chen, Qi; Yu, M. Y.

    2016-11-01

    The clustering process of charged grains often resembles a formation stage of colloidal and spongy matter, as well as some astrophysical objects. In this paper, molecular dynamics simulation is used to simulate the formation process of clusters of massive charged grains in plasmas. It is found that, from an initially uniform distribution of grains with Maxwellian velocity distribution, a statistically stationary system of clusters, each with different dynamic as well as thermodynamic characteristics, can form. The dependence of the asymptotic, of the final, state of the cluster system on the initial temperature and density of the grains is discussed.

  4. Thermodynamics and kinetics of vesicles formation processes.

    PubMed

    Guida, Vincenzo

    2010-12-15

    Vesicles are hollow aggregates, composed of bilayers of amphiphilic molecules, dispersed into and filled with a liquid solvent. These aggregates can be formed either as equilibrium or as out of equilibrium meta-stable structures and they exhibit a rich variety of different morphologies. The surprising richness of structures, the vast range of industrial applications and the presence of vesicles in a number of biological systems have attracted the interest of numerous researchers and scientists. In this article, we review both the thermodynamics and the kinetics aspects of the phenomena of formation of vesicles. We start presenting the thermodynamics of bilayer membranes formation and deformation, with the aim of deriving the conditions for the existence of equilibrium vesicles. Specifically, we use the results from continuum thermodynamics to discuss the possibility of formation of stable equilibrium vesicles, from both mixed amphiphiles and single component systems. We also link the bilayer membrane properties to the molecular structure of the starting amphiphiles. In the second part of this article, we focus on the dynamics and kinetics of vesiculation. We review the process of vesicles formation both from planar lamellar phase under shear and from isotropic micelles. In order to clarify the physical mechanisms of vesicles formation, we continuously draw a parallel between emulsification and vesiculation processes. Specifically, we compare the experimental results, the driving forces and the relative scaling laws identified for the two processes. Describing the dynamics of vesicles formation, we also discuss why non equilibrium vesicles can be formed by kinetics control and why they are meta-stable. Understanding how to control the properties, the stability and the formation process of vesicles is of fundamental importance for a vast number of industrial applications.

  5. Instabilities and structure formation in laser processing

    SciTech Connect

    Baeuerle, D.; Arenholz, E.; Arnold, N.; Heitz, J.; Kargl, P.B.

    1996-12-31

    This paper gives an overview on different types of instabilities and structure formation in various fields of laser processing. Among the examples discussed in detail are non-coherent structures observed in laser-induced chemical vapor deposition (LCVD), in laser-induced surface modifications, and in laser ablation of polymers.

  6. Bistatic SAR: Signal Processing and Image Formation.

    SciTech Connect

    Wahl, Daniel E.; Yocky, David A.

    2014-10-01

    This report describes the significant processing steps that were used to take the raw recorded digitized signals from the bistatic synthetic aperture RADAR (SAR) hardware built for the NCNS Bistatic SAR project to a final bistatic SAR image. In general, the process steps herein are applicable to bistatic SAR signals that include the direct-path signal and the reflected signal. The steps include preprocessing steps, data extraction to for a phase history, and finally, image format. Various plots and values will be shown at most steps to illustrate the processing for a bistatic COSMO SkyMed collection gathered on June 10, 2013 on Kirtland Air Force Base, New Mexico.

  7. Deciphering the Mode of Action of the Processive Polysaccharide Modifying Enzyme Dermatan Sulfate Epimerase 1 by Hydrogen–Deuterium Exchange Mass Spectrometry

    PubMed Central

    Tykesson, Emil; Mao, Yang; Maccarana, Marco; Pu, Yi; Gao, Jinshan; Lin, Cheng; Zaia, Joseph; Westergren-Thorsson, Gunilla; Ellervik, Ulf; Malmström, Lars; Malmström, Anders

    2015-01-01

    Distinct from template-directed biosynthesis of nucleic acids and proteins, the enzymatic synthesis of heterogeneous polysaccharides is a complex process that is difficult to study using common analytical tools. Therefore, the mode of action and processivity of those enzymes are largely unknown. Dermatan sulfate epimerase 1 (DS-epi1) is the predominant enzyme during the formation of iduronic acid residues in the glycosaminoglycan dermatan sulfate. Using recombinant DS-epi1 as a model enzyme, we describe a tandem mass spectrometry-based method to study the mode of action of polysaccharide processing enzymes. The enzyme action on the substrate was monitored by hydrogen-deuterium exchange mass spectrometry and the sequence information was then fed into mathematical models with two different assumptions of the mode of action for the enzyme: processive reducing end to non-reducing end, and processive non-reducing end to reducing end. Model data was scored by correlation to experimental data and it was found that DS-epi1 attacks its substrate on a random position, followed by a processive mode of modification towards the non-reducing end and that the substrate affinity of the enzyme is negatively affected by each additional epimerization event. It could also be shown that the smallest active substrate was the reducing end uronic acid in a tetrasaccharide and that octasaccharides and longer oligosaccharides were optimal substrates. The method of using tandem mass spectrometry to generate sequence information of the complex enzymatic products in combination with in silico modeling can be potentially applied to study the mode of action of other enzymes involved in polysaccharide biosynthesis. PMID:26900446

  8. Oligosaccharide formation during commercial pear juice processing.

    PubMed

    Willems, Jamie L; Low, Nicholas H

    2016-08-01

    The effect of enzyme treatment and processing on the oligosaccharide profile of commercial pear juice samples was examined by high performance anion exchange chromatography with pulsed amperometric detection and capillary gas chromatography with flame ionization detection. Industrial samples representing the major stages of processing produced with various commercial enzyme preparations were studied. Through the use of commercially available standards and laboratory scale enzymatic hydrolysis of pectin, starch and xyloglucan; galacturonic acid oligomers, glucose oligomers (e.g., maltose and cellotriose) and isoprimeverose were identified as being formed during pear juice production. It was found that the majority of polysaccharide hydrolysis and oligosaccharide formation occurred during enzymatic treatment at the pear mashing stage and that the remaining processing steps had minimal impact on the carbohydrate-based chromatographic profile of pear juice. Also, all commercial enzyme preparations and conditions (time and temperature) studied produced similar carbohydrate-based chromatographic profiles.

  9. Mutagen formation during commercial processing of foods.

    PubMed Central

    Krone, C A; Yeh, S M; Iwaoka, W T

    1986-01-01

    Levels of bacterial mutagenicity 3-17 times above spontaneous are generated during commercial thermal processing (canning) of foods, particularly foods high in protein. The potential for other processing operations, including pasteurization, dehydration, and concentration, to produce substances active in the Ames Salmonella assay was also examined. Two heated fish model systems, canned salmon and fried sole, were established by extracting mutagen precursors from fish tissues with water. The model system studies suggest that the limiting reactants for mutagen formation differ from one food product to another, and that Maillard type browning reactions are involved in mutagen production. Bisulfite treatment was found to inhibit mutagen formation in modal systems and whole food products. Isolation and partial characterization of the mutagens in both fried and canned pink salmon showed that at least three distinct mutagens were present. These mutagens exhibited HPLC retention time patterns on C18, cyano, and amino columns different than the major mutagens present in other cooked and grilled meats and fish. PMID:3530739

  10. Deciphering infant mortality

    NASA Astrophysics Data System (ADS)

    Berrut, Sylvie; Pouillard, Violette; Richmond, Peter; Roehner, Bertrand M.

    2016-12-01

    This paper is about infant mortality. In line with reliability theory, "infant" refers to the time interval following birth during which the mortality (or failure) rate decreases. This definition provides a systems science perspective in which birth constitutes a sudden transition falling within the field of application of the Transient Shock (TS) conjecture put forward in Richmond and Roehner (2016c). This conjecture provides predictions about the timing and shape of the death rate peak. It says that there will be a death rate spike whenever external conditions change abruptly and drastically and also predicts that after a steep rise there will be a much longer hyperbolic relaxation process. These predictions can be tested by considering living organisms for which the transient shock occurs several days after birth. Thus, for fish there are three stages: egg, yolk-sac and young adult phases. The TS conjecture predicts a mortality spike at the end of the yolk-sac phase and this timing is indeed confirmed by observation. Secondly, the hyperbolic nature of the relaxation process can be tested using very accurate Swiss statistics for postnatal death rates spanning the period from one hour immediately after birth through to age 10 years. It turns out that since the 19th century despite a significant and large reduction in infant mortality, the shape of the age-specific death rate has remained basically unchanged. Moreover the hyperbolic pattern observed for humans is also found for small primates as recorded in the archives of zoological gardens. Our overall objective is to identify a series of cases which start from simple systems and move step by step to more complex organisms. The cases discussed here we believe represent initial landmarks in this quest.

  11. Site formation processes at Zhoukoudian, China.

    PubMed

    Goldberg, P; Weiner, S; Bar-Yosef, O; Xu, Q; Liu, J

    2001-11-01

    Zhoukoudian is often cited for its human remains and the early evidence of fire. Yet, since its first excavations over 70 years ago, detailed studies of processes responsible for the accumulation of anthropogenic and geogenic sediments in the site have been sparse. This paper provides some details of site formation processes mainly through field observations of the extant section at Locality 1, and the use of soil micromorphology and Fourier Transform Infrared Spectrometry (FTIR) analyses of the sediments. Samples from Layers 10 through 3 show extensive water deposition of fine silt-sized material (reworked loess), including fine-grained organic matter. The dark organic-rich unit in Layer 10--often cited as one of the earliest evidence of fire--is a water-laid accumulation. Much of the fine-grained sediment was derived from outside Locality 1, implying that the site was open to varying extents throughout most of its depositional history. The 4-6 m accumulation of "ashes" in Layer 4 represents subaerial water-laid silt deposits derived from the loess-covered hillslopes surrounding the site. They presumably accumulated in an open depression that formed after the collapse of the brecciated roof deposits represented by Layer 6. Diagenesis is present in many of the Layers, and is exemplified by calcite precipitation and dissolution, and localized apatite (dahllite) replacement of calcite. In Layer 4 diagenesis is more advanced, including calcite/dahllite precipitation, subaerial weathering of the loess and associated precipitation of hematite, alteration of clay and the neoformation of quartz. Many of our conclusions concur with those of Teilhard de Chardin & Young published over 70 years ago.

  12. Situ microbial plugging process for subterranean formations

    DOEpatents

    McInerney, Michael J.; Jenneman, Gary E.; Knapp, Roy M.; Menzie, Donald E.

    1985-12-17

    Subterranean paths of water flow are impeded or changed by the facilitation of microbial growth therein. Either indigenous bacterial growth may be stimulated with nutrients or the formation may be first seeded with bacteria or their spores which inhibit fluid flow after proliferation. These methods and bacteria are usable to alter the flow of water in a waterflooded oil formation and to impede the outflow of contaminated water.

  13. Scale Free Processes in Galaxy Formation

    NASA Astrophysics Data System (ADS)

    Mandelker, Nir; Dekel, Avishai

    According to the ΛCDM paradigm of cosmology, galaxies form at the centers of dark matter (DM) halos. While galaxy formation involves complex baryonic physics, the formation of DM halos is governed solely by gravity and cosmology. As a result, many of their properties exhibit a near scale-free behaviour, self-similar in either halo mass, cosmic time or both. This is especially true in the Einstein-de Sitter (EdS) regime, valid at redshifts z >~ 1, when cosmological scaling relations become particularly simple, and in the narrow mass range of normal galaxies, where the fluctuation power spectrum can be approximated by a power law. Since many galaxy properties are strongly correlated with halo mass, they tend to exhibit a self-similar behaviour as well. A partial list of self-similar properties include the mass function of DM halos, the structure of the cosmic web, the accretion/merger rate of matter onto halos, the density profiles of DM halos and their angular momentum, which eventually determines the galaxy structure. We briefly review these below, and comment on how they can be used in conjunction with simple toy models to gain insight into galaxy formation.

  14. Particle contamination formation in magnetron sputtering processes

    SciTech Connect

    Selwyn, G.S.; Sequeda, F.; Huang, C.

    1997-07-01

    Defects caused by particulate contamination are an important concern in the fabrication of thin film products. Often, magnetron sputtering processes are used for this purpose. Particle contamination generated during thin film processing can be detected using laser light scattering, a powerful diagnostic technique which provides real-time, {ital in situ} imaging of particles {gt}0.3 {mu}m on the target, substrate, or in the plasma. Using this technique, we demonstrate that the mechanisms for particle generation, transport, and trapping during magnetron sputter deposition are different from the mechanisms reported in previously studied plasma etch processes, due to the inherent spatial nonuniformity of magnetically enhanced plasmas. During magnetron sputter deposition, one source of particle contamination is linked to portions of the sputtering target surface exposed to weaker plasma density. There, film redeposition induces filament or nodule growth. Sputter removal of these features is inhibited by the dependence of sputter yield on angle of incidence. These features enhance trapping of plasma particles, which then increases filament growth. Eventually the growths effectively {open_quotes}short-circuit{close_quotes} the sheath, causing high currents to flow through these features. This, in turn, causes mechanical failure of the growth resulting in fracture and ejection of the target contaminants into the plasma and onto the substrate. Evidence of this effect has been observed in semiconductor fabrication and storage disk manufacturing. Discovery of this mechanism in both technologies suggests it may be universal to many sputter processes. {copyright} {ital 1997 American Vacuum Society.}

  15. Processes and applications of electrostatic fiber formation

    NASA Astrophysics Data System (ADS)

    Rutledge, Gregory C.

    2008-12-01

    'Electrospinning' is an electrohydrodynamic jetting process that enables the production of continuous fibers, tubes and wires with diameters as small as 10 nm. The process itself is dependent upon electrostatic interactions such as charge-charge repulsion and charge-field interaction. The interplay of charge repulsion, viscoelasticity and surface tension gives rise to interesting electrohydrodynamic phenomena that challenge fundamental understanding as well as practical implementation and quality control in the final fibers. The morphology and diameter of these fibers can be understood and controlled through manipulation of fluid properties and operating parameters. The fibers thus produced are illustrative of nanotechnology in a 1-dimensional form, and have inspired considerable activity in the research community into their potential applications. Proposed uses range from high performance filtration media and membranes, to sensors and actuators, to medical devices and drug delivery vehicles. Two examples, tissue scaffold engineering and superhydrophobicity, are illustrated here.

  16. Evaluation as a Process: The Formative-Summative Continuum.

    ERIC Educational Resources Information Center

    Caudle, Sharon L.

    Rather than automatically presuming explicit conditions exist when designing an evaluation to fit the summative or formative mold, evaluators should think of an evaluation design as fitting between endpoints on an evaluation process continuum. Evaluators can blend techniques from both the formative and summative evaluation, matching actual program…

  17. Formative Evaluation as a Social Process: A Case Study.

    ERIC Educational Resources Information Center

    Salmon-Cox, Leslie; Holzner, Burkart

    This paper reports the results of a case study of the process of formative evaluation in the development of one unit of Individualized Science (IS). It is an analytic description of the curriculum project's experiences in formative evaluation rather than an evaluative critique. Following an introductory explanation, the IS program and the IS…

  18. Processing treatments for mitigating acrylamide formation in sweetpotato French fries

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Acrylamide formation in sweetpotato French fries (SPFF) is likely a potential health concern as there is an increasing demand for good-quality fries from carotene-rich sweetpotatoes (SP). This is the first report on acrylamide formation in SPFF as affected by processing methods. Acrylamide levels in...

  19. A Process Model of Family Formation and Development

    ERIC Educational Resources Information Center

    Garland, Diana R.

    2012-01-01

    Theoretical models of family formation have assumed sexual coupling as the foundation of family life. This article proposes instead a model of family formation predicated on the processes of taking care of one another, eating together, and sharing life together. The interpersonal dynamics that distinguish a family from other close relationships…

  20. Collisional and dynamical processes in moon and planet formation

    NASA Technical Reports Server (NTRS)

    Chapman, C. R.; Davis, D. R.; Weidenschilling, S. J.; Hartmann, W. K.; Spaute, D.

    1987-01-01

    Research on a variety of dynamical processes relevant to the formation of planets, satellites and ring systems is discussed. The main focus is on studies of accretionary formation of early protoplanets using a numerical model, structures and evolution of ring systems and individual bodies within planetary rings, and theories of lunar origin.

  1. Making Room for Formative Assessment Processes: A Multiple Case Study

    ERIC Educational Resources Information Center

    McEntarffer, Robert E.

    2012-01-01

    This qualitative instrumental multiple case study (Stake, 2005) explored how teachers made room for formative assessment processes in their classrooms, and how thinking about assessment changed during those formative assessment experiences. Data were gathered from six teachers over three months and included teacher interviews, student interviews,…

  2. EFFECT OF SEPARATION PROCESSES ON THE FORMATION OF BROMINATED THMS

    EPA Science Inventory

    Separation treatment processes are being investigated as a way to control the formation of disinfection by-products (DBPs) in finished waters. These processes remove natural organic matter before a disinfection is applied, thus limiting the amount of material available to form D...

  3. Analysis of the Particle Formation Process of Structured Microparticles.

    PubMed

    Baldelli, Alberto; Boraey, Mohammed A; Nobes, David S; Vehring, Reinhard

    2015-08-03

    The particle formation process for microparticles of cellulose acetate butyrate dried from an acetone solution was investigated experimentally and theoretically. A monodisperse droplet chain was used to produce solution microdroplets in a size range of 55-70 μm with solution concentrations of 0.37 and 10 mg/mL. As the droplets dried in a laminar air flow with a temperature of 30, 40, or 55 °C, the particle formation process was recorded by two independent optical methods. Dried particles in a size range of 10-30 μm were collected for morphology analysis, showing hollow, elongated particles whose structure was dependent on the drying gas temperature and initial solution concentration. The setup allowed comprehensive measurements of the particle formation process to be made, including the period after initial shell formation. The early particle formation process for this system was controlled by the diffusion of cellulose acetate butyrate in the liquid phase, whereas later stages of the process were dominated by shell buckling and folding.

  4. Polycyclic aromatic hydrocarbons' formation and occurrence in processed food.

    PubMed

    Singh, Lochan; Varshney, Jay G; Agarwal, Tripti

    2016-05-15

    Polycyclic aromatic hydrocarbons (PAHs) emerged as an important contaminant group in a gamut of processed food groups like dairy, nuts, herbs, beverages, meat products etc. Different cooking processes and processing techniques like roasting, barbecuing, grilling, smoking, heating, drying, baking, ohmic-infrared cooking etc. contribute towards its formation. The level of PAHs depends on factors like distance from heat source, fuel used, level of processing, cooking durations and methods, whereas processes like reuse, conching, concentration, crushing and storage enhance the amount of PAHs in some food items. This review paper provides insight into the impact of dietary intake of PAHs, its levels and formation mechanism in processed food items and possible interventions for prevention and reduction of the PAHs contamination. The gaps and future prospects have also been assessed.

  5. Diffused Matrix Format: a new storage and processing format for airborne hyperspectral sensor images.

    PubMed

    Martínez, Pablo; Cristo, Alejandro; Koch, Magaly; Pérez, Rosa Ma; Schmid, Thomas; Hernández, Luz M

    2010-01-01

    At present, hyperspectral images are mainly obtained with airborne sensors that are subject to turbulences while the spectrometer is acquiring the data. Therefore, geometric corrections are required to produce spatially correct images for visual interpretation and change detection analysis. This paper analyzes the data acquisition process of airborne sensors. The main objective is to propose a new data format called Diffused Matrix Format (DMF) adapted to the sensor's characteristics including its spectral and spatial information. The second objective is to compare the accuracy of the quantitative maps derived by using the DMF data structure with those obtained from raster images based on traditional data structures. Results show that DMF processing is more accurate and straightforward than conventional image processing of remotely sensed data with the advantage that the DMF file structure requires less storage space than other data formats. In addition the data processing time does not increase when DMF is used.

  6. On possibility of diamond formations in radiation process

    NASA Technical Reports Server (NTRS)

    Fisenko, A. V.; Semjonova, L. F.; Bolsheva, L. N.; Grachjova, T. V.; Verchovsky, A. B.; Shukolyukov, Yu. A.

    1993-01-01

    The possibility of diamond formation in radiation processes was checked by studying diamond contents in carburanium sample. The diamonds were not found and this result is discussed. At present one possible process of formation of nanometer-size diamond crystals in some meteorites and Earth's diamonds (carbonado), the radiation mechanism, is suggested: the formation of diamonds from carbonaceous matter in tracks of U fragment fissions and heavy fragmentation due to the action of energetic particles of cosmic rays. Bjakov et. al. have carried out the calculations and shown that the volume of formed diamonds in carbonaceous chondrites by radiation processes corresponds to discovery of diamond volume in chondrites. The discovery by Ozima et. al. of the unsupported fission of Xe and Kr in carbonado supports the supposition that carbonado could be formed by radiation processes. The possibility of diamond formation in radiation processes leads to the study of diamond contents in Earth's samples enriched by uranium and carbon. The attempt to release the diamonds from carburanium was undertaken.

  7. Morphology and formation process of diamond from glassy carbon

    NASA Astrophysics Data System (ADS)

    Miyamoto, Manabu; Akaishi, Minoru; Ohsawa, Toshikazu; Yamaoka, Shinobu; Fukunaga, Osamu

    1989-10-01

    Under static high pressure conditions in the presence of a catalyst metal, a diamond formation process was studied using glassy carbon as a starting source, which was prepared by pyrolysis of furfuryl alcohol resin. Above 1200 °C of the pyrolysis temperature, diamond formation was clearly observed in Ni, Fe, Co and their alloy catalysts. The hydrogen content in the starting carbon has a drastic effect on the diamond formation. The maximum content of the hydrogen in the glassy carbon had to be between 1200 and 2200 ppm to see diamond formation. In the Fe-rich catalyst, a characteristic needle-like diamond was formed due to the texture of the carbon source and the nature of the catalyst.

  8. Information Processing and Formation of Sociology of Science

    NASA Astrophysics Data System (ADS)

    Abe, Koichiro

    Progress and development in technology of information processing has not only effected gradually the fundamental purpose, that is providing exact information for people who need it, but also has offered many numerical data that are optimum to form Sociology of Science. To have more knowledge to understand the construction of the world with Sociology of Science can supply more devices for making scientific policy and can do more good for technology of information processing. This paper reviews these process looking through the process of formation of Sociology of Science.

  9. Investigation of formation mechanisms of chips in orthogonal cutting process

    NASA Astrophysics Data System (ADS)

    Ma, W.

    2012-08-01

    This work investigates the formation mechanisms of chips in orthogonal cutting of mild steel and the transformation conditions between various morphology chips. It is supposed that the modeling material follows the Johnson-Cook constitutive model. In orthogonal cutting process, both the plastic flow and the instability behaviors of chip materials are caused by the plane strain loadings. Therefore, the general instability behaviors of materials in plane strain state are first analyzed with linear perturbation method and a universal instability criterion is established. Based on the analytical results, the formation mechanisms of chips and the transformation conditions between continuous and serrated chips are further studied by instability phase diagram method. The results show that the chip formation strongly depends on the intensity ratios between shear and normal stresses. The ratios of dissipative rates of plastic work done by compression and shear stresses govern the transformation from continuous to serrated chips. These results are verified by the numerical simulations on the orthogonal cutting process.

  10. Satisfaction Formation Processes in Library Users: Understanding Multisource Effects

    ERIC Educational Resources Information Center

    Shi, Xi; Holahan, Patricia J.; Jurkat, M. Peter

    2004-01-01

    This study explores whether disconfirmation theory can explain satisfaction formation processes in library users. Both library users' needs and expectations are investigated as disconfirmation standards. Overall library user satisfaction is predicted to be a function of two independent sources--satisfaction with the information product received…

  11. Reducing the potential for processing contaminant formation in cereal products

    PubMed Central

    Curtis, Tanya Y.; Postles, Jennifer; Halford, Nigel G.

    2014-01-01

    Processing contaminants may be defined as substances that are produced in a food when it is cooked or processed, are not present or are present at much lower concentrations in the raw, unprocessed food, and are undesirable either because they have an adverse effect on product quality or because they are potentially harmful. The presence of very low levels of processing contaminants in common foods is becoming an increasingly important issue for the food industry, as developments in analytical techniques and equipment bring foods under closer and closer scrutiny. This review considers the formation of lipid oxidation products, hydrogenation of polyunsaturated fatty acids to prevent lipid oxidation and the associated risk of trans fatty acid formation. The formation of acrylamide in the Maillard reaction is described, as well as the genetic and agronomic approaches being taken to reduce the acrylamide-forming potential of cereal grain. The multiple routes for the formation of furan and associated chemicals, including hydroxymethylfurfuryl, are also described. The evolving regulatory and public perception situations for these processing contaminants and their implications for the cereal supply chain are discussed, emphasising the need for cereal breeders to engage with the contaminants issue. PMID:24882936

  12. Reducing the potential for processing contaminant formation in cereal products.

    PubMed

    Curtis, Tanya Y; Postles, Jennifer; Halford, Nigel G

    2014-05-01

    Processing contaminants may be defined as substances that are produced in a food when it is cooked or processed, are not present or are present at much lower concentrations in the raw, unprocessed food, and are undesirable either because they have an adverse effect on product quality or because they are potentially harmful. The presence of very low levels of processing contaminants in common foods is becoming an increasingly important issue for the food industry, as developments in analytical techniques and equipment bring foods under closer and closer scrutiny. This review considers the formation of lipid oxidation products, hydrogenation of polyunsaturated fatty acids to prevent lipid oxidation and the associated risk of trans fatty acid formation. The formation of acrylamide in the Maillard reaction is described, as well as the genetic and agronomic approaches being taken to reduce the acrylamide-forming potential of cereal grain. The multiple routes for the formation of furan and associated chemicals, including hydroxymethylfurfuryl, are also described. The evolving regulatory and public perception situations for these processing contaminants and their implications for the cereal supply chain are discussed, emphasising the need for cereal breeders to engage with the contaminants issue.

  13. Processing biological literature with customizable Web services supporting interoperable formats.

    PubMed

    Rak, Rafal; Batista-Navarro, Riza Theresa; Carter, Jacob; Rowley, Andrew; Ananiadou, Sophia

    2014-01-01

    Web services have become a popular means of interconnecting solutions for processing a body of scientific literature. This has fuelled research on high-level data exchange formats suitable for a given domain and ensuring the interoperability of Web services. In this article, we focus on the biological domain and consider four interoperability formats, BioC, BioNLP, XMI and RDF, that represent domain-specific and generic representations and include well-established as well as emerging specifications. We use the formats in the context of customizable Web services created in our Web-based, text-mining workbench Argo that features an ever-growing library of elementary analytics and capabilities to build and deploy Web services straight from a convenient graphical user interface. We demonstrate a 2-fold customization of Web services: by building task-specific processing pipelines from a repository of available analytics, and by configuring services to accept and produce a combination of input and output data interchange formats. We provide qualitative evaluation of the formats as well as quantitative evaluation of automatic analytics. The latter was carried out as part of our participation in the fourth edition of the BioCreative challenge. Our analytics built into Web services for recognizing biochemical concepts in BioC collections achieved the highest combined scores out of 10 participating teams. Database URL: http://argo.nactem.ac.uk.

  14. Processing biological literature with customizable Web services supporting interoperable formats

    PubMed Central

    Rak, Rafal; Batista-Navarro, Riza Theresa; Carter, Jacob; Rowley, Andrew; Ananiadou, Sophia

    2014-01-01

    Web services have become a popular means of interconnecting solutions for processing a body of scientific literature. This has fuelled research on high-level data exchange formats suitable for a given domain and ensuring the interoperability of Web services. In this article, we focus on the biological domain and consider four interoperability formats, BioC, BioNLP, XMI and RDF, that represent domain-specific and generic representations and include well-established as well as emerging specifications. We use the formats in the context of customizable Web services created in our Web-based, text-mining workbench Argo that features an ever-growing library of elementary analytics and capabilities to build and deploy Web services straight from a convenient graphical user interface. We demonstrate a 2-fold customization of Web services: by building task-specific processing pipelines from a repository of available analytics, and by configuring services to accept and produce a combination of input and output data interchange formats. We provide qualitative evaluation of the formats as well as quantitative evaluation of automatic analytics. The latter was carried out as part of our participation in the fourth edition of the BioCreative challenge. Our analytics built into Web services for recognizing biochemical concepts in BioC collections achieved the highest combined scores out of 10 participating teams. Database URL: http://argo.nactem.ac.uk. PMID:25006225

  15. Kinetics of Elementary Processes Relevant to Incipient Soot Formation

    SciTech Connect

    Lin, M C; Heaven, M C

    2008-04-30

    Soot formation and abatement processes are some of the most important and challenging problems in hydrocarbon combustion. The key reactions involved in the formation of polycyclic aromatic hydrocarbons (PAH's), the precursors to soot, remain elusive. Small aromatic species such as C5H5, C6H6 and their derivatives are believed to play a pivotal role in incipient soot formation. The goal of this project is to establish a kinetic database for elementary reactions relevant to soot formation in its incipient stages. In the past year, we have completed by CRDS the kinetics for the formation and decomposition of C6H5C2H2O2 in the C6H5C2H2 +O2 reaction and the formation of C10H7O2 in the C10H7 + O2 reaction by directly monitoring C6H5C2H2O2 and C10H7O2 radicals in the visible region; their mechanisms have been elucidated computationally by quantum-chemical calculations. The O + C2H5OH reaction has been studied experimentally and computationally and the OH + HNCN reaction has been investigated by ab initio molecular orbital calculation. In addition, a new pulsed slit molecular beam system has been constructed and tested for spectroscopic studies of aromatic radicals and their derivatives by the cavity ringdown technique (CRDS).

  16. Modified Polar-Format Software for Processing SAR Data

    NASA Technical Reports Server (NTRS)

    Chen, Curtis

    2003-01-01

    HMPF is a computer program that implements a modified polar-format algorithm for processing data from spaceborne synthetic-aperture radar (SAR) systems. Unlike prior polar-format processing algorithms, this algorithm is based on the assumption that the radar signal wavefronts are spherical rather than planar. The algorithm provides for resampling of SAR pulse data from slant range to radial distance from the center of a reference sphere that is nominally the local Earth surface. Then, invoking the projection-slice theorem, the resampled pulse data are Fourier-transformed over radial distance, arranged in the wavenumber domain according to the acquisition geometry, resampled to a Cartesian grid, and inverse-Fourier-transformed. The result of this process is the focused SAR image. HMPF, and perhaps other programs that implement variants of the algorithm, may give better accuracy than do prior algorithms for processing strip-map SAR data from high altitudes and may give better phase preservation relative to prior polar-format algorithms for processing spotlight-mode SAR data.

  17. Deciphering records of geomagnetic reversals

    NASA Astrophysics Data System (ADS)

    Valet, Jean-Pierre; Fournier, Alexandre

    2016-06-01

    Polarity reversals of the geomagnetic field are a major feature of the Earth's dynamo. Questions remain regarding the dynamical processes that give rise to reversals and the properties of the geomagnetic field during a polarity transition. A large number of paleomagnetic reversal records have been acquired during the past 50 years in order to better constrain the structure and geometry of the transitional field. In addition, over the past two decades, numerical dynamo simulations have also provided insights into the reversal mechanism. Yet despite the large paleomagnetic database, controversial interpretations of records of the transitional field persist; they result from two characteristics inherent to all reversals, both of which are detrimental to an ambiguous analysis. On the one hand, the reversal process is rapid and requires adequate temporal resolution. On the other hand, weak field intensities during a reversal can affect the fidelity of magnetic recording in sedimentary records. This paper is aimed at reviewing critically the main reversal features derived from paleomagnetic records and at analyzing some of these features in light of numerical simulations. We discuss in detail the fidelity of the signal extracted from paleomagnetic records and pay special attention to their resolution with respect to the timing and mechanisms involved in the magnetization process. Records from marine sediments dominate the database. They give rise to transitional field models that often lead to overinterpret the data. Consequently, we attempt to separate robust results (and their subsequent interpretations) from those that do not stand on a strong observational footing. Finally, we discuss new avenues that should favor progress to better characterize and understand transitional field behavior.

  18. The formation of blobs from a pure interchange process

    SciTech Connect

    Zhu, P.; Sovinec, C. R.; Hegna, C. C.

    2015-02-15

    In this work, we focus on examining a pure interchange process in a shear-less slab configuration as a prototype mechanism for blob formation. We employ full magnetohydrodynamic simulations to demonstrate that the blob-like structures can emerge through the nonlinear development of a pure interchange instability originating from a pedestal-like transition region. In the early nonlinear stage, filamentary structures develop and extend in the direction of the effective gravity. The blob-like structures appear when the radially extending filaments break off and disconnect from the core plasma. The morphology and the dynamics of these filaments and blobs vary dramatically with a sensitive dependence on the dissipation mechanisms in the system and the initial perturbation. Despite the complexity in morphology and dynamics, the nature of the entire blob formation process in the shear-less slab configuration remains strictly interchange without involving any change in magnetic topology.

  19. Collisional and dynamical processes in moon and planet formation

    NASA Technical Reports Server (NTRS)

    1979-01-01

    The collisional and dynamical processes in moon and planet formation are discussed. A hydrodynamic code of collision calculations, the orbital element changes due to gravitational scattering, a validation of the mass shifting algorithm, a theory of rotations, and the origin of asteroids are studied. A numerical model of planet growth is discussed and a methodology to evaluate the rate at which megaregolith increases its depth as a function of total accumulate number of impacts on an initially smooth, coherent surface is described.

  20. Formation characteristics of PCDD and PCDF during pyrolysis processes.

    PubMed

    Weber, R; Sakurai, T

    2001-12-01

    In recent years, pyrolysis processes have become technologies developed to industrial scale and discussed as alternatives to the existing waste combustion technology. However, little information is published regarding PCDD/F formation characteristics during pyrolysis processes. Two common shredder fractions--industrial light shredder (ILS) and refrigerators (REF)--both with high chlorine and copper content were pyrolysed for this pyrolysis study using a pilot plant with a capacity of 100 kg/h. At oxygen concentrations below 2% and temperatures between 430 degrees C and 470 degrees C, considerable amounts of PCDD/F were formed during the pyrolysis. More than 90% of total TEQ was found in the oil fraction (gas phase). The PCDD/PCDF ratio and the homologue pattern differed significantly from those formed during waste incineration. Considering mono- to octachlorinated congeners, up to 400 times more PCDF were formed compared to PCDD. For the investigated pyrolysis conditions, the formation of low chlorinated congeners was highly favoured. The distribution of TEQ within the individual congeners were very similar in all investigated runs. More than 80% of total TEQ stem from 2,3,7,8-substituted T4CDF and P5CDF. The isomer pattern, however, did not show significant differences compared to the common waste incineration pattern suggesting that the basic formation routes are similar.

  1. Elementary radical formation and conversion processes in. gamma. -irradiated polyvinylchloride

    SciTech Connect

    Torikai, A.; Adachi, T.; Fueki, K.

    1981-11-01

    Elementary processes of ..gamma..-irradiated polyvinylchloride (PVC) have been investigated by both electron spin resonance (ESR) and optical absorption measurements. On irradiating PVC film with ..gamma.. rays at -196/sup 0/C, alkyl-type radicals are produced. When the PVC film is warmed to room temperature, the radicals convert to polyenyl type. ..gamma.. irradiation of PVC film containing biphenyl (Ph/sub 2/) or pyrene (Py) at -196/sup 0/C yields the corresponding radical cation. The relative ESR peak heights of the radicals decrease and the G values for the formation of cation radicals increase with increasing additive concentrations. These facts indicate that energy is transferred from the precursor of the radicals to the additive. In the case of PVC film containing Py, the Py cation radical decreases the cyclohexadienyl-type radical from Py is produced by thermal annealing. A possible mechanism for radical formation and conversion is proposed.

  2. Modeling of Fume Formation from Shielded Metal Arc Welding Process

    NASA Astrophysics Data System (ADS)

    Sivapirakasam, S. P.; Mohan, Sreejith; Santhosh Kumar, M. C.; Surianarayanan, M.

    2017-01-01

    In this study, a semi-empirical model of fume formation rate (FFR) from a shielded metal arc welding (SMAW) process has been developed. The model was developed for a DC electrode positive (DCEP) operation and involves the calculations of droplet temperature, surface area of the droplet, and partial vapor pressures of the constituents of the droplet to predict the FFR. The model was further extended for predicting FFR from nano-coated electrodes. The model estimates the FFR for Fe and Mn assuming constant proportion of other elements in the electrode. Fe FFR was overestimated, while Mn FFR was underestimated. The contribution of spatters and other mechanism in the arc responsible for fume formation were neglected. A good positive correlation was obtained between the predicted and experimental FFR values which highlighted the usefulness of the model.

  3. Modeling of Fume Formation from Shielded Metal Arc Welding Process

    NASA Astrophysics Data System (ADS)

    Sivapirakasam, S. P.; Mohan, Sreejith; Santhosh Kumar, M. C.; Surianarayanan, M.

    2017-04-01

    In this study, a semi-empirical model of fume formation rate (FFR) from a shielded metal arc welding (SMAW) process has been developed. The model was developed for a DC electrode positive (DCEP) operation and involves the calculations of droplet temperature, surface area of the droplet, and partial vapor pressures of the constituents of the droplet to predict the FFR. The model was further extended for predicting FFR from nano-coated electrodes. The model estimates the FFR for Fe and Mn assuming constant proportion of other elements in the electrode. Fe FFR was overestimated, while Mn FFR was underestimated. The contribution of spatters and other mechanism in the arc responsible for fume formation were neglected. A good positive correlation was obtained between the predicted and experimental FFR values which highlighted the usefulness of the model.

  4. Processing treatments for mitigating acrylamide formation in sweetpotato French fries.

    PubMed

    Truong, Van-Den; Pascua, Yvette T; Reynolds, Rong; Thompson, Roger L; Palazoğlu, T Koray; Mogol, Burce Atac; Gökmen, Vural

    2014-01-08

    Acrylamide formation in sweetpotato French fries (SPFF) is likely a potential health concern as there is an increasing demand for good-quality fries from carotene-rich sweetpotatoes (SP). This is the first report on acrylamide formation in SPFF as affected by processing methods. Acrylamide levels in SPFF from untreated SP strips fried at 165 °C for 2, 3, and 5 min were 124.9, 255.5, and 452.0 ng/g fresh weight, which were reduced by about 7 times to 16.3, 36.9, and 58.3 ng/g, respectively, when the strips were subjected to processing that included water blanching and soaking in 0.5% sodium acid pyrophosphate before frying. An additional step of strip soaking in 0.4% calcium chloride solution before par-frying increased the calcium content from 0.2 to 0.8 mg/g and decreased the acrylamide levels to 6.3, 17.6, and 35.4 ng/g, respectively. SPFF with acrylamide level of <100 ng/g or several times lower than that of white potato French fries can be obtained by integrating processing treatments commonly used in the food industry.

  5. Carbon formation and metal dusting in advanced coal gasification processes

    SciTech Connect

    DeVan, J.H.; Tortorelli, P.F.; Judkins, R.R.; Wright, I.G.

    1997-02-01

    The product gases generated by coal gasification systems contain high concentrations of CO and, characteristically, have relatively high carbon activities. Accordingly, carbon deposition and metal dusting can potentially degrade the operation of such gasifier systems. Therefore, the product gas compositions of eight representative gasifier systems were examined with respect to the carbon activity of the gases at temperatures ranging from 480 to 1,090 C. Phase stability calculations indicated that Fe{sub 3}C is stable only under very limited thermodynamic conditions and with certain kinetic assumptions and that FeO and Fe{sub 0.877}S tend to form instead of the carbide. As formation of Fe{sub 3}C is a necessary step in the metal dusting of steels, there are numerous gasifier environments where this type of carbon-related degradation will not occur, particularly under conditions associated with higher oxygen and sulfur activities. These calculations also indicated that the removal of H{sub 2}S by a hot-gas cleanup system may have less effect on the formation of Fe{sub 3}C in air-blown gasifier environments, where the iron oxide phase can exist and is unaffected by the removal of sulfur, than in oxygen-blown systems, where iron sulfide provides the only potential barrier to Fe{sub 3}C formation. Use of carbon- and/or low-alloy steels dictates that the process gas composition be such that Fe{sub 3}C cannot form if the potential for metal dusting is to be eliminated. Alternatively, process modifications could include the reintroduction of hydrogen sulfide, cooling the gas to perhaps as low as 400 C and/or steam injection. If higher-alloy steels are used, a hydrogen sulfide-free gas may be processed without concern about carbon deposition and metal dusting.

  6. Process and apparatus for formation of photovoltaic compounds

    DOEpatents

    Hall, Robert B.; Rocheleau, Richard E.

    1985-01-01

    The invention relates to a process and apparatus for formation and deposition of thin films on a substrate, in a vacuum, by evaporation of the elements to form a Zn.sub.x Cd.sub.1-x S compound having a preselected fixed ratio of cadmium to zinc, characterized by the evaporation of cadmium and zinc at a rate the ratio of which is proportional to the stoichiometric ratio of those elements in the intended compound and evaporation of sulfur at a rate at least twice the combined rates of cadmium and zinc, and at least twice that required by the stoichiometry of the intended compound.

  7. DNA multi-ring formation via evaporation process

    NASA Astrophysics Data System (ADS)

    Zhang, Lu; Maheshwari, Siddharth; Chang, Hsueh-Chia; Zhu, Y. Elaine

    2007-03-01

    We present a study of multi-ring pattern formation of DNA aggregates during the solvent evaporation of a DNA droplet. When the contact line of a droplet is pinned at a solid substrate, a `coffee ring' pattern is often observed due to the outward flow during evaporation which carries the nonvolatile solute to the edge of the contact line. Here we report a remarkable observation of multiple rings of DNA stain, where stretched DNA molecules connect each ring. We use a high-speed confocal scanning microscope to investigate the kinetics of the multi-ring formation, when DNAs aggregate at the contact-line and cause a stick-slip receding process with periodic depinning of the contact line. A saw-tooth pattern in measured contact angle during droplet evaporation confirms the stick-slip receding dynamics, and a miscible viscous fingering pattern further confirms the stagnation flow responsible for the formation of consecutive rings. We also report a scaling behavior of the multi-ring wavelength with DNA concentration, droplet size and evaporation temperature, consistent with our proposed mechanism.

  8. Influence of small RNAs on biofilm formation process in bacteria.

    PubMed

    Ghaz-Jahanian, Mohammad Ali; Khodaparastan, Fatemeh; Berenjian, Aydin; Jafarizadeh-Malmiri, Hoda

    2013-11-01

    Small non-coding RNAs (sRNAs) play a significant role in regulation of bacterial physiological behaviors. After sensing any environmental cue such as fluctuation of nutrient concentration, temperature, pH, and osmolarity, these sRNAs interfere to transmit these signals to target regulators and genes. sRNAs have key role in biofilm formation process by base pairing with target mRNAs or interaction with modulating proteins to both positive and negative regulation mechanisms. There are various regulatory systems to characterize the initiation and formation of special bacterial biofilms that are mostly described as two component systems based on sRNAs functions. In this study, regulatory pathways that are important for biofilm formation and genetic responses to environmental stimuli in mature biofilms were evaluated. Some of the regulatory systems that produce common types of biofilms such as curli, PGA, cellulose and polysaccharides such as alginate, colonic acid, Psl and their involved sRNAs functions were also discussed.

  9. Chemical and Chemoenzymatic Synthesis of Glycoproteins for Deciphering Functions

    PubMed Central

    Wang, Lai-Xi; Amin, Mohammed N.

    2014-01-01

    Summary Glycoproteins are an important class of biomolecules involved in a number of biological recognition processes. However, natural and recombinant glycoproteins are usually produced as mixtures of glycoforms that differ in the structures of the pendent glycans, which are difficult to separate in pure glycoforms. As a result, synthetic homogeneous glycopeptides and glycoproteins have become indispensable probes for detailed structural and functional studies. A number of elegant chemical and biological strategies have been developed for synthetic construction of tailor-made, full-size glycoproteins to address specific biological problems. In this review, we highlight recent advances in chemical and chemoenzymatic synthesis of homogeneous glycoproteins. Selected examples are given to demonstrate the applications of tailor-made, glycan-defined glycoproteins for deciphering glycosylation functions. PMID:24439206

  10. Twenty years of protein interaction studies for biological function deciphering.

    PubMed

    Legrain, Pierre; Rain, Jean-Christophe

    2014-07-31

    Intensive methodological developments and technology innovation have been devoted to protein-protein interaction studies over 20years. Genetic indirect assays and sophisticated large scale biochemical analyses have jointly contributed to the elucidation of protein-protein interactions, still with a lot of drawbacks despite heavy investment in human resources and technologies. With the most recent developments in mass spectrometry and computational tools for studying protein content of complex samples, the initial goal of deciphering molecular bases of biological functions is now within reach. Here, we described the various steps of this process and gave examples of key milestones in this scientific story line. This article is part of a Special Issue entitled: 20years of Proteomics in memory of Viatliano Pallini. Guest Editors: Luca Bini, Juan J. Calvete, Natacha Turck, Denis Hochstrasser and Jean-Charles Sanchez.

  11. Pseudobulge Formation as a Dynamical Rather than a Secular Process

    NASA Astrophysics Data System (ADS)

    Guedes, Javiera; Mayer, Lucio; Carollo, Marcella; Madau, Piero

    2013-07-01

    We investigate the formation and evolution of the pseudobulge in "Eris," a high-resolution N-body + smoothed particle hydrodynamic cosmological simulation that successfully reproduces a Milky-Way-like massive late-type spiral in an cold dark matter universe. At the present epoch, Eris has a virial mass M vir ~= 8 × 1011 M ⊙, a photometric stellar mass M * = 3.2 × 1010 M ⊙, a bulge-to-total ratio B/T = 0.26, and a weak nuclear bar. We find that the bulk of the pseudobulge forms quickly at high redshift via a combination of non-axisymmetric disk instabilities and tidal interactions or mergers, both occurring on dynamical timescales, not through slow secular processes at lower redshift. Its subsequent evolution is not strictly secular either, and is closely intertwined with the evolution of the stellar bar. In fact, the structure that we recognize as a pseudobulge today evolved from a stellar bar that formed at high redshift due to tidal interactions with satellites, was destroyed by minor mergers at z ~ 3, re-formed shortly after, and weakened again following a steady gas inflow at z <~ 1. The gradual dissolution of the bar ensued at z ~ 1 and continues until the present without increasing the stellar velocity dispersion in the inner regions. In this scenario, the pseudobulge is not a separate component from the inner disk in terms of formation path; rather, it is the first step in the inside-out formation of the baryonic disk, in agreement with the fact that pseudobulges of massive spiral galaxies typically have a dominant old stellar population. If our simulations do indeed reproduce the formation mechanisms of massive spirals, then the progenitors of late-type galaxies should have strong bars and small photometric pseudobulges at high redshift.

  12. PSEUDOBULGE FORMATION AS A DYNAMICAL RATHER THAN A SECULAR PROCESS

    SciTech Connect

    Guedes, Javiera; Mayer, Lucio; Carollo, Marcella; Madau, Piero

    2013-07-20

    We investigate the formation and evolution of the pseudobulge in 'Eris', a high-resolution N-body + smoothed particle hydrodynamic cosmological simulation that successfully reproduces a Milky-Way-like massive late-type spiral in an cold dark matter universe. At the present epoch, Eris has a virial mass M{sub vir} {approx_equal} 8 Multiplication-Sign 10{sup 11} M{sub Sun }, a photometric stellar mass M{sub *} = 3.2 Multiplication-Sign 10{sup 10} M{sub Sun }, a bulge-to-total ratio B/T = 0.26, and a weak nuclear bar. We find that the bulk of the pseudobulge forms quickly at high redshift via a combination of non-axisymmetric disk instabilities and tidal interactions or mergers, both occurring on dynamical timescales, not through slow secular processes at lower redshift. Its subsequent evolution is not strictly secular either, and is closely intertwined with the evolution of the stellar bar. In fact, the structure that we recognize as a pseudobulge today evolved from a stellar bar that formed at high redshift due to tidal interactions with satellites, was destroyed by minor mergers at z {approx} 3, re-formed shortly after, and weakened again following a steady gas inflow at z {approx}< 1. The gradual dissolution of the bar ensued at z {approx} 1 and continues until the present without increasing the stellar velocity dispersion in the inner regions. In this scenario, the pseudobulge is not a separate component from the inner disk in terms of formation path; rather, it is the first step in the inside-out formation of the baryonic disk, in agreement with the fact that pseudobulges of massive spiral galaxies typically have a dominant old stellar population. If our simulations do indeed reproduce the formation mechanisms of massive spirals, then the progenitors of late-type galaxies should have strong bars and small photometric pseudobulges at high redshift.

  13. Particle Formation by Supercritical Fluid Extraction and Expansion Process

    PubMed Central

    Zhou, Junbo; Li, Haiting; Quan, Can

    2013-01-01

    Supercritical fluid extraction and expansion (SFEE) patented technology combines the advantages of both supercritical fluid extraction (SFE) and rapid expansion of supercritical solution (RESS) with on-line coupling, which makes the nanoparticle formation feasible directly from matrix such as Chinese herbal medicine. Supercritical fluid extraction is a green separation technology, which has been developed for decades and widely applied in traditional Chinese medicines or natural active components. In this paper, a SFEE patented instrument was firstly built up and controlled by LABVIEW work stations. Stearic acid was used to verify the SFEE process at optimized condition; via adjusting the preexpansion pressure and temperature one can get different sizes of particles. Furthermore, stearic acid was purified during the SFEE process with HPLC-ELSD detecting device; purity of stearic acid increased by 19%, and the device can purify stearic acid. PMID:24223031

  14. Aroma formation by immobilized yeast cells in fermentation processes.

    PubMed

    Nedović, V; Gibson, B; Mantzouridou, T F; Bugarski, B; Djordjević, V; Kalušević, A; Paraskevopoulou, A; Sandell, M; Šmogrovičová, D; Yilmaztekin, M

    2015-01-01

    Immobilized cell technology has shown a significant promotional effect on the fermentation of alcoholic beverages such as beer, wine and cider. However, genetic, morphological and physiological alterations occurring in immobilized yeast cells impact on aroma formation during fermentation processes. The focus of this review is exploitation of existing knowledge on the biochemistry and the biological role of flavour production in yeast for the biotechnological production of aroma compounds of industrial importance, by means of immobilized yeast. Various types of carrier materials and immobilization methods proposed for application in beer, wine, fruit wine, cider and mead production are presented. Engineering aspects with special emphasis on immobilized cell bioreactor design, operation and scale-up potential are also discussed. Ultimately, examples of products with improved quality properties within the alcoholic beverages are addressed, together with identification and description of the future perspectives and scope for cell immobilization in fermentation processes.

  15. The Stratigraphic Expression of Formative Processes in Channels

    NASA Astrophysics Data System (ADS)

    Hubbard, S. M.; Covault, J. A.; Fildani, A.; Romans, B.

    2014-12-01

    The stratigraphic record of sinuous fluvial and deep sea channel deposits contains a wealth of information about formative sedimentary processes. For fluvial systems, deposits are considered in the context of processes observed in rivers, with the point bar facies model, as an example, representing a well-established linkage between process and product. A direct link has not been achieved in the deep sea as direct monitoring of coarse-grained sediment transport is challenging, exacerbated by the sporadic and infrequent nature of flows. Until a method for direct observation is developed and widely applied, the stratigraphic record of sediment transfer in the deep sea provides a critical perspective and unique insight into processes that shape not only ancient basin margin slopes, but also the present day seascape. Despite the obvious similarity in sinuous planforms of open, single thread fluvial and deep sea channels, outcrop characteristics, validated in many instances by experimental and theoretical work, indicate different processes. Meandering fluvial systems are most commonly represented by deposits that reflect point bar migration, a process whereby bank erosion and bar growth are genetically linked. At the bed scale, cross-stratification reflects bedload sediment transport and deposition by traction sedimentation. Single thread deep sea channel-fill strata are commonly characterized by sandstone-filled channelform bodies, which reflect both traction and suspension sedimentation. Heterolithic thin beds and cross-stratification can be locally preserved above channel bases and against channel margins, but the majority of depositional thickness comprises tabular sandstone turbidites that bi-directionally lap onto channel edges. The stratal record indicates a distinction between phases of channel maintenance (e.g., erosion, sediment bypass) and phases of substantial infilling with coarse-grained sediment - they are not contemporaneous. This is a key departure from

  16. Are amphitheater headed canyons indicative of a particular formative process?

    NASA Astrophysics Data System (ADS)

    Ryan, A. J.; Whipple, K. X.; Johnson, J. P.

    2012-12-01

    Tributary canyons with amphitheater-shaped heads have previously been interpreted as evidence for groundwater seepage erosion, particularly in environments where fluvial processes are assumed to be negligible. However, some have questioned whether this canyon morphology is truly diagnostic of a particular formative process. We seek to determine the relative roles of fluvial and groundwater-related processes and the strength of stratigraphic control on the Colorado Plateau through a combination of fieldwork and GIS analysis. Amphitheater valleys may have overhanging or steep-sided headwalls with a semicircular plan-view pattern. It is reasonable to assume that this form is a result of focused erosion at the base of the headwall (i.e. sapping). Two frequently cited agents may lead to undermining: plunge-pool scour at the base of waterfalls and seepage induced weathering and erosion where the groundwater table intersects the land surface. Both processes are enhanced where weaker, less permeable layers underlie stronger cap rock. We conducted preliminary fieldwork in two locations on the Colorado Plateau, where there are many classic examples of amphitheater headed canyons. The Escalante River landscape is highly variable with a range of canyon and valley-head forms, many of which cut through the thick Navajo Sandstone into the underlying shale and sand of the Kayenta Formation. Northeast of Escalante National Monument, at the base of the Henry Mountains, is Tarantula Mesa. The canyons there are also considerably variable, with nearly all containing at least one abrupt amphitheater knickpoint at the valley head or farther downstream. Our observations are presented here with an analysis of the canyon profiles, surrounding topography, and potential structural controls. We have found that nearly all amphitheaters in both locales show signs of groundwater seepage weathering and plausibly seepage erosion. However, many also contain plunge pools and evidence of substantial

  17. POX 186: A Dwarf Galaxy in the Process of Formation?

    NASA Astrophysics Data System (ADS)

    Corbin, Michael R.; Vacca, William D.

    2002-12-01

    We present deep U-, V-, and I-band images of the ``ultracompact'' blue dwarf galaxy POX 186 obtained with the Planetary Camera 2 of the Hubble Space Telescope. We have also obtained a near-ultraviolet spectrum of the object with the Space Telescope Imaging Spectrograph and combine this with a new ground-based optical spectrum. The images confirm the galaxy to be extremely small, with a maximum extent of only 300 pc, a luminosity of ~10-4L*, and an estimated mass of ~107 Msolar. Its morphology is highly asymmetric, with a tail of material on its western side that may be tidal in origin. The U-band image shows this tail to be part of a stream of material in which stars have recently formed. Most of the star formation in the galaxy is, however, concentrated in a central, compact (d~10-15 pc) star cluster. We estimate this cluster to have a total mass of ~105 Msolar, to be forming stars at a rate of less than 0.05 yr-1, and to have a maximum age of a few million years. The outer regions of the galaxy are significantly redder than the cluster, with V-I colors consistent with a population dominated by K and M stars. From our analysis of the optical spectrum we find the galaxy to have a metallicity Z~=0.06 Zsolar and to contain a significant amount of internal dust [E(B-V)~=0.28] both values agree with previous estimates. While these results rule out earlier speculation that POX 186 is a protogalaxy, its morphology, mass, and active star formation suggest that it represents a recent (within ~108 yr) collision between two clumps of stars of subgalactic size (~100 pc). POX 186 may thus be a very small dwarf galaxy that, dynamically speaking, is still in the process of formation. This interpretation is supported by the fact that it resides in a void, so its morphology cannot be explained as the result of an encounter with a more massive galaxy. Clumps of stars this small may represent the building blocks required by hierarchical models of galaxy formation, and these results

  18. Modeling Coupled Processes in Clay Formations for Radioactive Waste Disposal

    SciTech Connect

    Liu, Hui-Hai; Rutqvist, Jonny; Zheng, Liange; Sonnenthal, Eric; Houseworth, Jim; Birkholzer, Jens

    2010-08-31

    As a result of the termination of the Yucca Mountain Project, the United States Department of Energy (DOE) has started to explore various alternative avenues for the disposition of used nuclear fuel and nuclear waste. The overall scope of the investigation includes temporary storage, transportation issues, permanent disposal, various nuclear fuel types, processing alternatives, and resulting waste streams. Although geologic disposal is not the only alternative, it is still the leading candidate for permanent disposal. The realm of geologic disposal also offers a range of geologic environments that may be considered, among those clay shale formations. Figure 1-1 presents the distribution of clay/shale formations within the USA. Clay rock/shale has been considered as potential host rock for geological disposal of high-level nuclear waste throughout the world, because of its low permeability, low diffusion coefficient, high retention capacity for radionuclides, and capability to self-seal fractures induced by tunnel excavation. For example, Callovo-Oxfordian argillites at the Bure site, France (Fouche et al., 2004), Toarcian argillites at the Tournemire site, France (Patriarche et al., 2004), Opalinus clay at the Mont Terri site, Switzerland (Meier et al., 2000), and Boom clay at Mol site, Belgium (Barnichon et al., 2005) have all been under intensive scientific investigations (at both field and laboratory scales) for understanding a variety of rock properties and their relations with flow and transport processes associated with geological disposal of nuclear waste. Clay/shale formations may be generally classified as indurated and plastic clays (Tsang et al., 2005). The latter (including Boom clay) is a softer material without high cohesion; its deformation is dominantly plastic. For both clay rocks, coupled thermal, hydrological, mechanical and chemical (THMC) processes are expected to have a significant impact on the long-term safety of a clay repository. For

  19. Multi-modes processes for stretched spiral vortex formation

    NASA Astrophysics Data System (ADS)

    Horiuti, Kiyosi

    2004-11-01

    We studied a process for formation of the stretched spiral vortex (Lundgren 1982) in incompressible homogeneous isotropic turbulence. It was shown that multi modes exist for the configuration of alignment between the vorticity vectors along the vortex tube core and the vorticity vector along the sheet which emanates from and wraps around the tube core. A representative one is that generated via a roll-up of the vortex sheet through focusing, in which these two vorticity vectors were parallel. Alternative mechanism for formation of this parallel configuration was through the interaction of two different sheets which were initially placed perpendicular to each other. These two sheets generated a weak circulation and it gradually accumulated to form the tube core region. These two sheets were entrained by the tube core and the spiral sheets emanating from the tube core was formed. The tubes in this mode persisted for a rather long period of time. In another mode, the vorticity vectors along the sheet were in the direction transverse to those along the tube core. It was found that this mode often takes an asymmetric configuration in which the vorticity vectors along one of the sheets were parallel to those along the tube, while the vectors along another sheet were transverse to those along the tube. The configuration in which the vorticity vectors along both sheets were transverse to those along the tube core (Pullin and Lundgren 2001) was rarely found. Intense energy cascade took place with the stretching of the spiral vortex sheets. As the Reynolds number was increased, the frequency of occurrence of the spiral vortex formation increased, and the energy spectrum showed a profile close to the -5/3 law.

  20. The mineralogy and formation processes of Mars soil

    NASA Technical Reports Server (NTRS)

    Banin, Amos

    1992-01-01

    The mineralogical nature of Mars soil is far from being understood, nor are the formation time and weathering processes known. Quantitatively, the two major mineral-forming elements in Mars soil are silicon and iron, constituting 44 and 19 percent of the soils as SiO4 and Fe2O3, respectively. The silicate phases have been studied only briefly, mostly because of their limited spectral fingerprinting in the VIS and NIR. Much attention was given to the iron minerals in the soil, due to their pronounced absorption in the VIS and NIR, making them easily detectable by telescopic observations. The available information on Mars soil mineralogy, mostly obtained by remote sensing, is reviewed, and it is hypothesized that it leads to the suggestion that nanophase short-range-order (amorphous) phases of the silicates and iron oxides abound in the soil.

  1. Basics of Polar-Format algorithm for processing Synthetic Aperture Radar images.

    SciTech Connect

    Doerry, Armin Walter

    2012-05-01

    The purpose of this report is to provide a background to Synthetic Aperture Radar (SAR) image formation using the Polar Format (PFA) processing algorithm. This is meant to be an aid to those tasked to implement real-time image formation using the Polar Format processing algorithm.

  2. FORMATION PROCESS AND HISTORICAL FUNCTIONS OF OLD AKIHA ROAD

    NASA Astrophysics Data System (ADS)

    Nakane, Yoji; Okuda, Masao; Kani, Yukihiko; Hayakawa, Kiyoshi; Matsui, Tamotsu

    An object of this study is the old Akiha road located along the southern parts of the Akaishi Mountains in Sizuoka Prefecture. The old Akiha road between Hamamatsu city in Enshu and Iida city in Shinshu had been utilized by people for the purposes of making a pilgrimage, megalithic faith, transporting obsidian since the primitive age, practicing the mountaineering asceticism, operating the military activities in the warlike age, transporting salt from coastal area to mountainous area and so on. Through the investigation of literature, site reconnaissance and hearing, the formation process and the historical functions of the old Akiha road were studied, including the situation in medieval times or before. As the results, it was elucidated that the oldest road between two cities had located over the Hyoukoshi Pass, the road routes had the lowering trend from mountainside to riverside, and the historical functions of old Akiha road were the passage for transportation of various kinds of goods and human being, faith and culture.

  3. Fastest Formation Routes of Nanocarbons in Solution Plasma Processes

    NASA Astrophysics Data System (ADS)

    Morishita, Tetsunori; Ueno, Tomonaga; Panomsuwan, Gasidit; Hieda, Junko; Yoshida, Akihito; Bratescu, Maria Antoaneta; Saito, Nagahiro

    2016-11-01

    Although solution-plasma processing enables room-temperature synthesis of nanocarbons, the underlying mechanisms are not well understood. We investigated the routes of solution-plasma-induced nanocarbon formation from hexane, hexadecane, cyclohexane, and benzene. The synthesis rate from benzene was the highest. However, the nanocarbons from linear molecules were more crystalline than those from ring molecules. Linear molecules decomposed into shorter olefins, whereas ring molecules were reconstructed in the plasma. In the saturated ring molecules, C–H dissociation proceeded, followed by conversion into unsaturated ring molecules. However, unsaturated ring molecules were directly polymerized through cation radicals, such as benzene radical cation, and were converted into two- and three-ring molecules at the plasma–solution interface. The nanocarbons from linear molecules were synthesized in plasma from small molecules such as C2 under heat; the obtained products were the same as those obtained via pyrolysis synthesis. Conversely, the nanocarbons obtained from ring molecules were directly synthesized through an intermediate, such as benzene radical cation, at the interface between plasma and solution, resulting in the same products as those obtained via polymerization. These two different reaction fields provide a reasonable explanation for the fastest synthesis rate observed in the case of benzene.

  4. Fastest Formation Routes of Nanocarbons in Solution Plasma Processes

    PubMed Central

    Morishita, Tetsunori; Ueno, Tomonaga; Panomsuwan, Gasidit; Hieda, Junko; Yoshida, Akihito; Bratescu, Maria Antoaneta; Saito, Nagahiro

    2016-01-01

    Although solution-plasma processing enables room-temperature synthesis of nanocarbons, the underlying mechanisms are not well understood. We investigated the routes of solution-plasma-induced nanocarbon formation from hexane, hexadecane, cyclohexane, and benzene. The synthesis rate from benzene was the highest. However, the nanocarbons from linear molecules were more crystalline than those from ring molecules. Linear molecules decomposed into shorter olefins, whereas ring molecules were reconstructed in the plasma. In the saturated ring molecules, C–H dissociation proceeded, followed by conversion into unsaturated ring molecules. However, unsaturated ring molecules were directly polymerized through cation radicals, such as benzene radical cation, and were converted into two- and three-ring molecules at the plasma–solution interface. The nanocarbons from linear molecules were synthesized in plasma from small molecules such as C2 under heat; the obtained products were the same as those obtained via pyrolysis synthesis. Conversely, the nanocarbons obtained from ring molecules were directly synthesized through an intermediate, such as benzene radical cation, at the interface between plasma and solution, resulting in the same products as those obtained via polymerization. These two different reaction fields provide a reasonable explanation for the fastest synthesis rate observed in the case of benzene. PMID:27841288

  5. Internal social processes of discipline formation: the case of kinanthropometry.

    PubMed

    Vangrunderbeek, Hans; Claessens, Albrecht L; Delheye, Pascal

    2013-01-01

    In 1972, the term 'kinanthropometry', derived from the Greek words 'kinein' (to move), 'anthropos' (human) and 'metrein' (to measure), was launched in the international, Francophone journal Kinanthropologie by the Canadian William Ross and the Belgians, Marcel Hebbelinck, Bart Van Gheluwe and Marie-Louise Lemmens. The authors defined this neologism as 'the scientific discipline for the study of the size, shape, proportion, scope and composition of the human being and its gross motor functions'. Presenting a theoretical framework for the analysis of the internal social processes of discipline formation - derived from the social history-of-science tradition - this article critically examines whether kinanthropometry was indeed promoted and developed by its community members as a scientific discipline. Therefore, the focus will be on its conceptualisation and positioning within the field of kinanthropology/kinesiology and on its development by a scholarly association, i.e. the International Working Group on Kinanthropometry (IWGK). The strong emphasis of the kinanthropometry community on the standardisation of measurement techniques and its practical and professional application hampered its disciplinary development. Findings of this study could serve as a basis for future 'fundamental' investigations addressing questions of disciplinary development within the field(s) of physical education, kinesiology and sport science(s).

  6. Deciphering Antarctic Intermediate Water Variability during the PLIO-PLEISTOCENE

    NASA Astrophysics Data System (ADS)

    Karas, C.; deMenocal, P. B.; Goldstein, S. L.

    2015-12-01

    Antarctic Intermediate Water (AAIW) plays a fundamental role in the modern global thermohaline circulation because it is the coldwater route from the Southern Hemisphere to the North Atlantic Ocean replacing North Atlantic Deep Water (NADW) (e.g. Oppo and Curry, 2012). Additionally, AAIW is also an important source water in (sub)tropical upwelling regions in the equatorial eastern Pacific and Benguela region (Kubota et al., 2014; Sarmiento et al., 2004). Deciphering AAIW variability through time is critical to understanding its role in global climate change (e.g. Santoso and England, 2004). Our study focuses on reconstructing AAIW during the warm Pliocene (~4 million years ago) and early Pleistocene. This time period marks the transition from warm Pliocene greenhouse conditions towards icehouse conditions, which most likely affected AAIW variability (Karas et al., 2011). To reconstruct changes in AAIW formation, northward extent and possible influence on (sub)tropical upwelling regions, we will use foraminiferal neodymium isotopes (ɛNd) and benthic Mg/Ca from South Atlantic Site 516 and Southwest Pacific Site 1125.

  7. Cogeneration systems and processes for treating hydrocarbon containing formations

    DOEpatents

    Vinegar, Harold J.; Fowler, Thomas David; Karanikas, John Michael

    2009-12-29

    A system for treating a hydrocarbon containing formation includes a steam and electricity cogeneration facility. At least one injection well is located in a first portion of the formation. The injection well provides steam from the steam and electricity cogeneration facility to the first portion of the formation. At least one production well is located in the first portion of the formation. The production well in the first portion produces first hydrocarbons. At least one electrical heater is located in a second portion of the formation. At least one of the electrical heaters is powered by electricity from the steam and electricity cogeneration facility. At least one production well is located in the second portion of the formation. The production well in the second portion produces second hydrocarbons. The steam and electricity cogeneration facility uses the first hydrocarbons and/or the second hydrocarbons to generate electricity.

  8. Rapid gas hydrate formation processes: Will they work?

    DOE PAGES

    Brown, Thomas D.; Taylor, Charles E.; Bernardo, Mark P.

    2010-06-07

    Researchers at DOE’s National Energy Technology Laboratory (NETL) have been investigating the formation of synthetic gas hydrates, with an emphasis on rapid and continuous hydrate formation techniques. The investigations focused on unconventional methods to reduce dissolution, induction, nucleation and crystallization times associated with natural and synthetic hydrates studies conducted in the laboratory. Numerous experiments were conducted with various high-pressure cells equipped with instrumentation to study rapid and continuous hydrate formation. The cells ranged in size from 100 mL for screening studies to proof-of-concept studies with NETL’s 15-Liter Hydrate Cell. The results from this work demonstrate that the rapid and continuousmore » formation of methane hydrate is possible at predetermined temperatures and pressures within the stability zone of a Methane Hydrate Stability Curve.« less

  9. Rapid gas hydrate formation processes: Will they work?

    SciTech Connect

    Brown, Thomas D.; Taylor, Charles E.; Bernardo, Mark P.

    2010-06-07

    Researchers at DOE’s National Energy Technology Laboratory (NETL) have been investigating the formation of synthetic gas hydrates, with an emphasis on rapid and continuous hydrate formation techniques. The investigations focused on unconventional methods to reduce dissolution, induction, nucleation and crystallization times associated with natural and synthetic hydrates studies conducted in the laboratory. Numerous experiments were conducted with various high-pressure cells equipped with instrumentation to study rapid and continuous hydrate formation. The cells ranged in size from 100 mL for screening studies to proof-of-concept studies with NETL’s 15-Liter Hydrate Cell. The results from this work demonstrate that the rapid and continuous formation of methane hydrate is possible at predetermined temperatures and pressures within the stability zone of a Methane Hydrate Stability Curve.

  10. Challenges of deciphering gastric cancer heterogeneity

    PubMed Central

    Hudler, Petra

    2015-01-01

    Gastric cancer is in decline in most developed countries; however, it still accounts for a notable fraction of global mortality and morbidity related to cancer. High-throughput methods are rapidly changing our view and understanding of the molecular basis of gastric carcinogenesis. Today, it is widely accepted that the molecular complexity and heterogeneity, both inter- and intra-tumour, of gastric adenocarcinomas present significant obstacles in elucidating specific biomarkers for early detection of the disease. Although genome-wide sequencing and gene expression studies have revealed the intricate nature of the molecular changes that occur in tumour landscapes, the collected data and results are complex and sometimes contradictory. Several aberrant molecules have already been tested in clinical trials, although their diagnostic and prognostic utilities have not been confirmed thus far. The gold standard for the detection of sporadic gastric cancer is still the gastric endoscopy, which is considered invasive. In addition, genome-wide association studies have confirmed that genetic variations are important contributors to increased cancer risk and could participate in the initiation of malignant transformation. This hypothesis could in part explain the late onset of sporadic gastric cancers. The elaborate interplay of polymorphic low penetrance genes and lifestyle and environmental risk factors requires additional research to decipher their relative impacts on tumorigenesis. The purpose of this article is to present details of the molecular heterogeneity of sporadic gastric cancers at the DNA, RNA, and proteome levels and to discuss issues relevant to the translation of basic research data to clinically valuable tools. The focus of this work is the identification of relevant molecular changes that could be detected non-invasively. PMID:26457012

  11. Deciphering Ecohydrological Interactions Using Stable Isotopes

    NASA Astrophysics Data System (ADS)

    McDonnell, J.; Evaristo, J. A.; Jasechko, S.

    2014-12-01

    Deciphering the nature of ecohydrological interconnections and scaling that knowledge gained at single points to watersheds is challenging. One tool that that has proved useful in this regard is stable isotope tracing. Single isotope studies have been used recently to quantify landuse change effects on streamflow source apportionment and ecological effects on transit time distributions of water at the catchment scale. However, most work to date has assumed that plant transpiration, groundwater recharge and streamflow are all sourced or mediated by the same well mixed reservoir—the soil. Recent work in Oregon and Mexico has shown evidence of ecohydrological separation, whereby different subsurface compartmentalized pools of water supply either plant transpiration fluxes or the combined fluxes of groundwater recharge and streamflow. However, these findings have not yet been widely tested. Here we assemble the first dual isotope database for δ2H and δ18O extracted from 47 globally-distributed stable isotopic datasets. We use these data to test the ecohydrological separation hypothesis. We combine this dual isotope dataset with global precipitation, streamwater, groundwater and soil water datasets. Our results show that precipitation, streamwater and groundwater from the 47 sites plot approximately along the δ2H/δ18O slope of eight, suggesting that local precipitation inputs supply streamwater and groundwater. Soil waters extracted from the 47 studies plot below the regression of local streamwater and groundwater with a slope of 6.6±0.05 ‰. Local plant xylem waters from our matched dataset plot on a slope 6.6±0.07 ‰ consistent with local soil waters. The tight association of soil water slopes and not that of local groundwater or streamflow suggests that plants use soil water that does not itself contribute to groundwater recharge or stream water. This ubiquity of subsurface water compartmentalization is surprising and has important implications for how we

  12. Formation and processing of organics in the early solar system.

    PubMed

    Kerridge, J F

    1999-01-01

    Until pristine samples can be returned from cometary nuclei, primitive meteorites represent our best source of information about organic chemistry in the early solar system. However, this material has been affected by secondary processing on asteroidal parent bodies which probably did not affect the material now present in cometary nuclei. Production of meteoritic organic matter apparently involved the following sequence of events: Molecule formation by a variety of reaction pathways in dense interstellar clouds; Condensation of those molecules onto refractory interstellar grains; Irradiation of organic-rich interstellar-grain mantles producing a range of molecular fragments and free radicals; Inclusion of those interstellar grains into the protosolar nebula with probable heating of at least some grain mantles during passage through the shock wave bounding the solar accretion disc; Agglomeration of residual interstellar grains and locally produced nebular condensates into asteroid-sized planetesimals; Heating of planetesimals by decay of extinct radionuclides; Melting of ice to produce liquid water within asteroidal bodies; Reaction of interstellar molecules, fragments and radicals with each other and with the aqueous environment, possibly catalysed by mineral grains; Loss of water and other volatiles to space yielding a partially hydrated lithology containing a complex suite of organic molecules; Heating of some of this organic matter to generate a kerogen-like complex; Mixing of heated and unheated material to yield the meteoritic material now observed. Properties of meteoritic organic matter believed to be consistent with this scenario include: Systematic decrease of abundance with increasing C number in homologous series of characterisable molecules; Complete structural diversity within homologous series; Predominance of branched-chain isomers; Considerable isotopic variability among characterisable molecules and within kerogen-like material; Substantial

  13. Deciphering the Minimal Algorithm for Development and Information-genesis

    NASA Astrophysics Data System (ADS)

    Li, Zhiyuan; Tang, Chao; Li, Hao

    During development, cells with identical genomes acquires different fates in a highly organized manner. In order to decipher the principles underlining development, we used C.elegans as the model organism. Based on a large set of microscopy imaging, we first constructed a ``standard worm'' in silico: from the single zygotic cell to about 500 cell stage, the lineage, position, cell-cell contact and gene expression dynamics are quantified for each cell in order to investigate principles underlining these intensive data. Next, we reverse-engineered the possible gene-gene/cell-cell interaction rules that are capable of running a dynamic model recapitulating the early fate decisions during C.elegans development. we further formulized the C.elegans embryogenesis in the language of information genesis. Analysis towards data and model uncovered the global landscape of development in the cell fate space, suggested possible gene regulatory architectures and cell signaling processes, revealed diversity and robustness as the essential trade-offs in development, and demonstrated general strategies in building multicellular organisms.

  14. Heating hydrocarbon containing formations in a checkerboard pattern staged process

    SciTech Connect

    de Rouffignac, Eric Pierre; Pingo-Almada, Monica M; Miller, David Scott

    2009-06-02

    Method for treating a hydrocarbon containing formation are described herein. Methods may include providing heat to two or more first sections of the formation with one or more first heaters in two or more of the first sections. The provided heat may mobilize first hydrocarbons in two or more of the first sections. At least some of the mobilized first hydrocarbons are produced through production wells located in two or more second sections of the formation. The first sections and the second sections are arranged in a checkerboard pattern. A portion of at least one of the second sections proximate at least one production well is provided some heat from the mobilized first hydrocarbons, but is not conductively heated by heat from the first heaters. Heat may be provided to the second sections with one or more second heaters in the second sections to further heat the second sections.

  15. Heating hydrocarbon containing formations in a line drive staged process

    DOEpatents

    Miller, David Scott

    2009-07-21

    Method for treating a hydrocarbon containing formation are described herein. Methods may include providing heat to a first section of the formation with one or more first heaters in the first section. First hydrocarbons may be heated in the first section such that at least some of the first hydrocarbons are mobilized. At least some of the mobilized first hydrocarbons may be produced through a production well located in a second section of the formation. The second section may be located substantially adjacent to the first section. A portion of the second section may be provided some heat from the mobilized first hydrocarbons, but is not conductively heated by heat from the first heaters. Heat may be provided to the second section with one or more second heaters in the second section to further heat the second section.

  16. Process for selectively plugging subterranean formations with a melamine resin

    SciTech Connect

    Falk, D.O.

    1984-09-25

    Highly permeable zones in a subterranean formation are selectively plugged by injecting a melamine formaldehyde solution via a well into the highly permeable zones. The solution is water soluble and preferentially enters water-containing zones where it reacts to form a resin at a temperature of from about 25/sup 0/ C. to about 120/sup 0/ C. and a pH of from about 7 to 12 and over a period of from about 1 to 4 days. The resulting resin substantially plugs the highly permeable zones in the formation.

  17. Pyruvate formate lyase acts as a formate supplier for metabolic processes during anaerobiosis in Staphylococcus aureus.

    PubMed

    Leibig, Martina; Liebeke, Manuel; Mader, Diana; Lalk, Michael; Peschel, Andreas; Götz, Friedrich

    2011-02-01

    Previous studies demonstrated an upregulation of pyruvate formate lyase (Pfl) and NAD-dependent formate dehydrogenase (Fdh) in Staphylococcus aureus biofilms. To investigate their physiological role, we constructed fdh and pfl deletion mutants (Δfdh and Δpfl). Although formate dehydrogenase activity in the fdh mutant was lost, it showed little phenotypic alterations under oxygen-limited conditions. In contrast, the pfl mutant displayed pleiotropic effects and revealed the importance of formate production for anabolic metabolism. In the pfl mutant, no formate was produced, glucose consumption was delayed, and ethanol production was decreased, whereas acetate and lactate production were unaffected. All metabolic alterations could be restored by addition of formate or complementation of the Δpfl mutant. In compensation reactions, serine and threonine were consumed better by the Δpfl mutant than by the wild type, suggesting that their catabolism contributes to the refilling of formyl-tetrahydrofolate, which acts as a donor of formyl groups in, e.g., purine and protein biosynthesis. This notion was supported by reduced production of formylated peptides by the Δpfl mutant compared to that of the parental strain, as demonstrated by weaker formyl-peptide receptor 1 (FPR1)-mediated activation of leukocytes with the mutant. FPR1 stimulation could also be restored either by addition of formate or by complementation of the mutation. Furthermore, arginine consumption and arc operon transcription were increased in the Δpfl mutant. Unlike what occurred with the investigated anaerobic conditions, a biofilm is distinguished by nutrient, oxygen, and pH gradients, and we thus assume that Pfl plays a significant role in the anaerobic layer of a biofilm. Fdh might be critical in (micro)aerobic layers, as formate oxidation is correlated with the generation of NADH/H(+), whose regeneration requires respiration.

  18. BATHYMETRIC IRREGULARITIES, JET FORMATION, AND SUBSEQUENT MIXING PROCESSES

    EPA Science Inventory

    It is well known that bathymetric contours influence and steer currents and that irregularities in bathymetry contribute to the formation of aquatic non-buoyant jets and buoyant plumes. For example, bathymetric irregularities can channel flow through canyons or accelerate flow ov...

  19. Single molecule image formation, reconstruction and processing: introduction.

    PubMed

    Ashok, Amit; Piestun, Rafael; Stallinga, Sjoerd

    2016-07-01

    The ability to image at the single molecule scale has revolutionized research in molecular biology. This feature issue presents a collection of articles that provides new insights into the fundamental limits of single molecule imaging and reports novel techniques for image formation and analysis.

  20. Well completion process for formations with unconsolidated sands

    DOEpatents

    Davies, David K.; Mondragon, III, Julius J.; Hara, Philip Scott

    2003-04-29

    A method for consolidating sand around a well, involving injecting hot water or steam through well casing perforations in to create a cement-like area around the perforation of sufficient rigidity to prevent sand from flowing into and obstructing the well. The cement area has several wormholes that provide fluid passageways between the well and the formation, while still inhibiting sand inflow.

  1. Defining Sustainable Universities Following Public Opinion Formation Process

    ERIC Educational Resources Information Center

    Zaptcioglu Celikdemir, Deniz; Gunay, Gonca; Katrinli, Alev; Penbek Alpbaz, Sebnem

    2017-01-01

    Purpose: The purpose of this paper is to define the sustainable university in Turkey, by considering perspectives of various stakeholders such as experts, intellectual, public, political parties and media using public opinion formation analysis. The paper aims to re-define the "sustainable university" with all dimensions including…

  2. Core Formation Under Dynamic Conditions: Physical Processes and Geochemical Signatures

    NASA Technical Reports Server (NTRS)

    Rushmer, T.; Gaetani, G.; Jones, J. H.; Sparks, J.

    2001-01-01

    We have experimentally investigated liquid metal segregation from a solid silicate matrix under conditions of applied stress. Liquid moves in fractures and formation of fayalitic olivine from orthopyroxene by migrating Fe-Ni-S-O liquids is observed. Additional information is contained in the original extended abstract.

  3. Optically thin ice clouds in Arctic; Formation processes

    NASA Astrophysics Data System (ADS)

    Jouan, Caroline; Pelon, Jacques; Girard, Eric; Blanchet, Jean-Pierre; Wobrock, Wolfram; Gayet, Jean-Franćois; Schwarzenböck, Alfons; Gultepe, Ismail; Delanoë, Julien; Mioche, Guillaume

    2010-05-01

    Arctic ice cloud formation during winter is poorly understood mainly due to lack of observations and the remoteness of this region. Yet, their influence on Northern Hemisphere weather and climate is of paramount importance, and the modification of their properties, linked to aerosol-cloud interaction processes, needs to be better understood. Large concentration of aerosols in the Arctic during winter is associated to long-range transport of anthropogenic aerosols from the mid-latitudes to the Arctic. Observations show that sulphuric acid coats most of these aerosols. Laboratory and in-situ measurements show that at cold temperature (< -30°C), acidic coating lowers the freezing point and deactivates ice nuclei (IN). Therefore, the IN concentration is reduced in these regions and there is less competition for the same available moisture. As a result, large ice crystals form in relatively small concentrations. It is hypothesized that the observed low concentration of large ice crystals in thin ice clouds is linked to the acidification of aerosols. To check this, it is necessary to analyse cloud properties in the Arctic. Extensive measurements from ground-based sites and satellite remote sensing (CloudSat and CALIPSO) reveal the existence of two types of extended optically thin ice clouds (TICs) in the Arctic during the polar night and early spring. The first type (TIC-1) is seen only by the lidar, but not the radar, and is found in pristine environment whereas the second type (TIC-2) is detected by both sensors, and is associated with high concentration of aerosols, possibly anthropogenic. TIC-2 is characterized by a low concentration of ice crystals that are large enough to precipitate. To further investigate the interactions between TICs clouds and aerosols, in-situ, airborne and satellite measurements of specific cases observed during the POLARCAT and ISDAC field experiments are analyzed. These two field campaigns took place respectively over the North Slope of

  4. Optically thin ice clouds in Arctic : Formation processes

    NASA Astrophysics Data System (ADS)

    Jouan, C.; Girard, E.; Pelon, J.; Blanchet, J.; Wobrock, W.; Gultepe, I.; Gayet, J.; Delanoë, J.; Mioche, G.; Adam de Villiers, R.

    2010-12-01

    Arctic ice cloud formation during winter is poorly understood mainly due to lack of observations and the remoteness of this region. Their influence on Northern Hemisphere weather and climate is of paramount importance, and the modification of their properties, linked to aerosol-cloud interaction processes, needs to be better understood. Large concentration of aerosols in the Arctic during winter is associated to long-range transport of anthropogenic aerosols from the mid-latitudes to the Arctic. Observations show that sulphuric acid coats most of these aerosols. Laboratory and in-situ measurements show that at cold temperature (<-30°C), acidic coating lowers the freezing point and deactivates ice nuclei (IN). Therefore, the IN concentration is reduced in these regions and there is less competition for the same available moisture. As a result, large ice crystals form in relatively small concentrations. It is hypothesized that the observed low concentration of large ice crystals in thin ice clouds is linked to the acidification of aerosols. Extensive measurements from ground-based sites and satellite remote sensing (CloudSat and CALIPSO) reveal the existence of two types of extended optically thin ice clouds (TICs) in the Arctic during the polar night and early spring. The first type (TIC-1) is seen only by the lidar, but not the radar, and is found in pristine environment whereas the second type (TIC-2) is detected by both sensors, and is associated with high concentration of aerosols, possibly anthropogenic. TIC-2 is characterized by a low concentration of ice crystals that are large enough to precipitate. To further investigate the interactions between TICs clouds and aerosols, in-situ, airborne and satellite measurements of specific cases observed during the POLARCAT and ISDAC field experiments are analyzed. These two field campaigns took place respectively over the North Slope of Alaska and Northern part of Sweden in April 2008. Analysis of cloud type can be

  5. Process for biological material carbon-carbon bond formation

    DOEpatents

    Hollingsworth, Rawle I.; Jung, Seunho; Mindock, Carol A.

    1998-01-01

    A process for providing vicinal dimethyl long chain between alkyl groups of organic compounds is described. The process uses intact or disrupted cells of various species of bacteria, particularly Thermoanaerobacter sp., Sarcina sp. and Butyrivibrio sp. The process can be conducted in an aqueous reaction mixture at room temperatures.

  6. Process for biological material carbon-carbon bond formation

    DOEpatents

    Hollingsworth, R.I.; Jung, S.; Mindock, C.A.

    1998-12-22

    A process for providing vicinal dimethyl long chain between alkyl groups of organic compounds is described. The process uses intact or disrupted cells of various species of bacteria, particularly Thermoanaerobacter sp., Sarcina sp. and Butyrivibrio sp. The process can be conducted in an aqueous reaction mixture at room temperatures. 8 figs.

  7. Formation of porous metal oxides in the anodization process.

    PubMed

    Sample, C; Golovin, A A

    2006-10-01

    A theory of the formation of nanoscale porous structures in oxides of metals grown by anodization is developed. It is shown that a growing oxide layer can become unstable which yields the formation of a spatially irregular array of pores. The instability is shown to result from a nonlinear dependence of electrochemical kinetics at the metal-oxide and oxide-electrolyte interfaces on the overpotential which is governed by the Butler-Volmer relation. The conditions for the instability of the oxide layer are found. The dependence of the oxide conductivity on the electric field is taken into account and is shown to have a destabilizing effect. A weakly nonlinear analysis is performed and it shows that the system evolution near the instability threshold is described by the Kuramoto-Sivashinsky equation. Farther from threshold, in the long-wave approximation, a system of strongly nonlinear equations is derived and solved numerically; this system describes the formation of deep irregular pores. In a particular case, a self-similar solution describing the propagation of a pore with a paraboloidal shape is found.

  8. [Marcov processes and neuronal engram formation--a model].

    PubMed

    Mager, P P

    1975-01-01

    The multivariate partial autocorrelation bases on the noncircular serial correlation matrices and is a problem of eigen values. Autoregressive oscillations of a time series and its order can be tested. MARCOV processes are 1st order processes, they are found during the conversion of short into long time memory (conditioned avoidance response).

  9. Vetting and Letting: Cohabiting Stepfamily Formation Processes in Low-Income Black Families

    PubMed Central

    Reid, Megan; Golub, Andrew

    2015-01-01

    The authors examined cohabiting union formation processes by analyzing in-depth interview data collected from 30 individuals in cohabiting relationships: 15 low-income Black mothers of adolescents and their partners. Prior research suggests that cohabiting union formation is a gradual, nondeliberative process. In contrast, most couples in this study described a gradual but highly deliberative process. Mothers focused primarily on vetting their partners to ensure child well-being and less on when and how their partners officially came to live with them, a process the authors call vetting and letting. Mothers delineated 4 strategies to ensure their child’s well-being when vetting their partners, and their partners reported that they understood the importance of participating in this process. The authors argue that vetting and letting is a child-centered family formation process, not a partner-centered union formation process, and that cohabiting union processes may vary substantially by subpopulation. PMID:26556922

  10. Transition and separation process in brine channels formation

    SciTech Connect

    Berti, Alessia; Bochicchio, Ivana; Fabrizio, Mauro

    2016-02-15

    In this paper, we discuss the formation of brine channels in sea ice. The model includes a time-dependent Ginzburg-Landau equation for the solid-liquid phase change, a diffusion equation of the Cahn-Hilliard kind for the solute dynamics, and the heat equation for the temperature change. The macroscopic motion of the fluid is also considered, so the resulting differential system couples with the Navier-Stokes equation. The compatibility of this system with the thermodynamic laws and a maximum theorem is proved.

  11. Process for recovering hydrocarbons from a hydrocarbon-bearing formation

    SciTech Connect

    Alston, R.B.; Braden, W.B.; Flournoy, K.H.

    1980-03-11

    A method is described for transporting heavy crude oil through a pipeline which involves introducing into a pipeline or well-bore with the viscous hydrocarbons an aqueous solution containing (1) a sulfonate surfactant, (2) a rosin soap or a naphthenic acid soap and, optionally (3) coupling agent whereby there is spontaneously formed a low viscosity, salt tolerant, oil-in-water emulsion. Also disclosed is a method of recovery of hydrocarbons from a hydrocarbon bearing formation employing an aqueous solution containing (1) a sulfonate surfactant, (2) a rosin soap or a naphthenic acid soap and, optionally (3) a coupling agent.

  12. Formation processes and time scales for meteorite parent bodies

    NASA Technical Reports Server (NTRS)

    Weidenschilling, S. J.

    1988-01-01

    The transition from small particles suspended in the solar nebula to the planetesimals (asteroids) that became the parent bodies of meteorites is examined. Planetesimals probably grew by coagulation of grain aggregates that collided due to different rates of settling and drag-induced orbital decay. Their growth was accompanied by radial transport of solids, possibly sufficient to deplete the primordial mass in the asteroid zone, but with relatively little mixing. The formation of asteroid-sized planetesimals was probably rapid, on a time scale less than 1 Myr.

  13. Star formation and cosmic massive black hole formation, a universal process organized by angular momenta

    SciTech Connect

    Colgate, S. A.

    2004-01-01

    It is suggested that star formation is organized following the same principles as we have applied in a recent explanation of galaxy and massive black hole formation. In this scenario angular momentum is randomly distributed by tidal torquing among condensations, Lyman-{alpha} clouds or cores for star formation during the initial non-linear phase of collapse. This angular momentum is characterized by the parameter, {lambda}, the ratio of the angular momentum of the cloud to that of a Keplerian orbit with the same central mass and radius. This parameter is calculated in very many simulations of structure formation of the universe as well as core formation and appears to be universal and independent of any scale. The specific angular momentum during the collapse of every cloud is locally conserved and universally produces a near flat rotation curve M{sub formation of a flat rotation curve (protostellar) disk of mass M{sub dsk} {sup -}30 M{sub o} of radius R{sub dsk} {approx_equal} 1100 AU or 5.4 x 10{sup -3} pc. In such a disk {Sigma} {proportional_to} 1/R and reaches the RVI condition at R{sub crit} {approx_equal} 40 AU where M{sub

  14. Effect of channel plane form on formation process of Sandbars

    NASA Astrophysics Data System (ADS)

    Takahashi, Gen; Yasuda, Hiroyasu

    Almost no explanation is given about development process of sand bar in non-straighten channel because the phenomenon of sand bar has been investigated using straighten channel. This study conducted a numerical experiment of development process of sand bar in a meandering channel and a figure-of-eight(gourd) as fixed wall. The results shows that the development process clearly differs in channel of straighten, meandering and figure-of-eight(gourd). The result of figure-of-eight(gourd) doesn't occur mode degradation and keep multiple bars.

  15. Stellar Dynamical Processes in Massive Star and Star Cluster Formation

    NASA Astrophysics Data System (ADS)

    Tan, Jonathan; Eyer, L.

    2009-01-01

    We study how high precision astrometric measurements by SIM and GAIA of stars involved in dynamical ejection events from star clusters can constrain theories of massive star and star cluster formation. We focus on the Orion Nebula Cluster (ONC). First, we investigate the scientific potential associated with an accurate measurement of the distance and proper motion of Theta 1 Ori C, which is the most massive star in the cluster and was recently involved (about 4000 years ago) in the ejection of a B star: the Becklin-Neugebauer (BN) star. The motion of the BN star has taken it close to a massive protostar, known as source I, where it appears to have influenced the accretion and outflow activity, most likely by a tidal interaction with the accretion disk. An accurate proper motion measurement of Theta 1 Ori C will constrain BN's initial motion, allowing us to search for deflections caused by the gravitational potential of the massive protostar. Second, we search the Hipparcos catalog for candidate runaway stars, i.e. that have been dynamically ejected from the cluster over the course of the last several Myr. SIM and GAIA observations of these stars will be needed to confirm their origin from the ONC. The results of this study will constrain the star cluster formation timescale and the statistics of the population of ejected stars. JCT acknowledges support from from NSF CAREER grant AST-0645412 and a grant from NASA for SIM Science Studies.

  16. Formation of chondrules and CAIs by nebular processes

    NASA Technical Reports Server (NTRS)

    Palme, H.

    1994-01-01

    Chondrules are essential components of most chondritic meteorites. Carbonaceous chondrites, with the exception of CI chondrites, contain 30-50% chondrules, ordinary and enstatite chondrites even more. A better understanding of chondrule formation will therefore lead to an improved understanding of the origin of meteorites. Most studies of chondrules are, however, concerned with their texture and mineralogy. As chondrules, by definition, passed through a molten stage, their present texture and mineralogy can only provide information on conditions of crystallization from a melt and the subsequent solid-state cooling history. Information concerning chondrule formation is contained in their chemical and isotopic composition. The two most important observations relevant to the chemistry of the chondrules are their generally low Fe content and the large compositional variability of chondrules from a single meteorite, reflected in major variations of Mg/Si ratios, of Al and other refractory element abundances, total Fe, metal (Fe, Ni), and sulfide. This large compositional variability is surprising considering the uniform and nearly solar composition of bulk chondrites, which, in some cases, consist of more than 90% of chondrules.

  17. Chondritic Meteorites: Nebular and Parent-Body Formation Process

    NASA Technical Reports Server (NTRS)

    Rubin, Alan E.

    1997-01-01

    Chondritic meteorites are the products of condensation, agglomeration and accretion of material in the solar nebula; these objects are the best sources of information regarding processes occurring during the early history of the solar system. We obtain large amounts of high-quality chemical and petrographic data and use them to infer chemical fractionation processes that occurred in the solar nebula and on meteorite parent bodies during thermal metamorphism, shock metamorphism and aqueous alteration. We compare diverse groups of chondrites and model their different properties in terms of processes that differed at different nebular locations or on different parent-bodies. In order to expand our set of geochemically important elements (particularly Si, C, P and S) and to distinguish the different oxidation states of Fe, Greg Kallemeyn spent three months (1 Sept. - 30 Nov. 1995) at the Smithsonian Institution to learn Eugene Jarosewich's wet chemical techniques. Key specimens from the recently established CK, CR and R chondrite groups were analyzed.

  18. Formation of hypernuclei in evaporation and fission processes

    NASA Astrophysics Data System (ADS)

    Botvina, A. S.; Buyukcizmeci, N.; Ergun, A.; Ogul, R.; Bleicher, M.; Pochodzalla, J.

    2016-11-01

    There are excellent opportunities to produce excited heavy hyperresidues in relativistic hadron and peripheral heavy-ion collisions. We investigate the disintegration of such residues into hypernuclei via evaporation of baryons and light clusters and their fission. Previously these processes were well known for normal nuclei as the decay channels at low excitation energies. We have generalized these models for the case of hypermatter. In this way we make extension of nuclear reaction studies at low temperature into the strange sector. We demonstrate how the new decay channels can be integrated in the whole disintegration process. Their importance for mass and isotope distributions of produced hyperfragments is emphasized. New and exotic isotopes obtained within these processes may provide a unique opportunity for investigating hyperon interaction in nuclear matter.

  19. Chondritic Meteorites: Nebular and Parent-Body Formation Processes

    NASA Technical Reports Server (NTRS)

    Rubin, Alan E.; Lindstrom, David (Technical Monitor)

    2002-01-01

    It is important to identify features in chondrites that formed as a result of parent-body modification in order to disentangle nebular and asteroidal processes. However, this task is difficult because unmetamorphosed chondritic meteorites are mixtures of diverse components including various types of chondrules, chondrule fragments, refractory and mafic inclusions, metal-sulfide grains and fine-grained matrix material. Shocked chondrites can contain melt pockets, silicate-darkened material, metal veins, silicate melt veins, and impact-melt-rock clasts. This grant paid for several studies that went far in helping to distinguish primitive nebular features from those produced during asteroidal modification processes.

  20. Thermoplastic processing of proteins for film formation--a review.

    PubMed

    Hernandez-Izquierdo, V M; Krochta, J M

    2008-03-01

    Increasing interest in high-quality food products with increased shelf life and reduced environmental impact has encouraged the study and development of edible and/or biodegradable polymer films and coatings. Edible films provide the opportunity to effectively control mass transfer among different components in a food or between the food and its surrounding environment. The diversity of proteins that results from an almost limitless number of side-chain amino-acid sequential arrangements allows for a wide range of interactions and chemical reactions to take place as proteins denature and cross-link during heat processing. Proteins such as wheat gluten, corn zein, soy protein, myofibrillar proteins, and whey proteins have been successfully formed into films using thermoplastic processes such as compression molding and extrusion. Thermoplastic processing can result in a highly efficient manufacturing method with commercial potential for large-scale production of edible films due to the low moisture levels, high temperatures, and short times used. Addition of water, glycerol, sorbitol, sucrose, and other plasticizers allows the proteins to undergo the glass transition and facilitates deformation and processability without thermal degradation. Target film variables, important in predicting biopackage performance under various conditions, include mechanical, thermal, barrier, and microstructural properties. Comparisons of film properties should be made with care since results depend on parameters such as film-forming materials, film formulation, fabrication method, operating conditions, testing equipment, and testing conditions. Film applications include their use as wraps, pouches, bags, casings, and sachets to protect foods, reduce waste, and improve package recyclability.

  1. Modified Process For Formation Of Silicon Carbide Matrix Composites

    NASA Technical Reports Server (NTRS)

    Behrendt, Donald R.; Singh, Mrityunjay

    1996-01-01

    Modified version of process for making SiC-fiber/SiC-matrix composite material reduces damage to SiC (SCS-6) fibers and to carbon-rich coatings on fibers. Modification consists of addition of second polymer-infiltration-and-pyrolysis step to increase carbon content of porous matrix before infiltration with liquid silicon or silicon alloy.

  2. Particle contamination formation and detection in magnetron sputtering processes

    SciTech Connect

    Selwyn, G.S.; Weiss, C.A.; Sequeda, F.; Huang, C.

    1996-10-01

    Defects caused by particulate contamination are an important concern in the fabrication of thin film products. Often, magnetron sputtering processes are used for this purpose. Particle contamination can cause electrical shorting, pin holes, problems with photolithography, adhesion failure, as well as visual and cosmetic defects. Particle contamination generated during thin film processing can be detected using laser light scattering, a powerful diagnostic technique that provides real-time, {ital in-situ} imaging of particles > 0.3 {mu}m in diameter. Using this technique, the causes, sources and influences on particles in plasma and non-plasma and non-plasma processes may be independently evaluated and corrected. Several studies employing laser light scattering have demonstrated both homogeneous and heterogeneous causes of particle contamination. In this paper, we demonstrate that the mechanisms for particle generation, transport and trapping during magnetron sputter deposition are different from the mechanisms reported in previously studied plasma etch processes. During magnetron sputter deposition, one source of particle contamination is linked to portions of the sputtering target surface exposed to weaker plasma density. In this region, film redeposition is followed by filament or nodule growth and enhanced trapping which increases filament growth. Eventually the filaments effectively ``short circuit`` the sheath, causing high currents to flow through these features. This, in turn, causes heating failure of the filament fracturing and ejecting the filaments into the plasma and onto the substrate. Evidence of this effect has been observed in semiconductor (IC) fabrication and storage disk manufacturing. Discovery of this mechanism in both technologies suggests that this mechanism may be universal to many sputtering processes.

  3. Deciphering Neuron-Glia Compartmentalization in Cortical Energy Metabolism

    PubMed Central

    Jolivet, Renaud; Magistretti, Pierre J.; Weber, Bruno

    2009-01-01

    Energy demand is an important constraint on neural signaling. Several methods have been proposed to assess the energy budget of the brain based on a bottom-up approach in which the energy demand of individual biophysical processes are first estimated independently and then summed up to compute the brain's total energy budget. Here, we address this question using a novel approach that makes use of published datasets that reported average cerebral glucose and oxygen utilization in humans and rodents during different activation states. Our approach allows us (1) to decipher neuron-glia compartmentalization in energy metabolism and (2) to compute a precise state-dependent energy budget for the brain. Under the assumption that the fraction of energy used for signaling is proportional to the cycling of neurotransmitters, we find that in the activated state, most of the energy (∼80%) is oxidatively produced and consumed by neurons to support neuron-to-neuron signaling. Glial cells, while only contributing for a small fraction to energy production (∼6%), actually take up a significant fraction of glucose (50% or more) from the blood and provide neurons with glucose-derived energy substrates. Our results suggest that glycolysis occurs for a significant part in astrocytes whereas most of the oxygen is utilized in neurons. As a consequence, a transfer of glucose-derived metabolites from glial cells to neurons has to take place. Furthermore, we find that the amplitude of this transfer is correlated to (1) the activity level of the brain; the larger the activity, the more metabolites are shuttled from glia to neurons and (2) the oxidative activity in astrocytes; with higher glial pyruvate metabolism, less metabolites are shuttled from glia to neurons. While some of the details of a bottom-up biophysical approach have to be simplified, our method allows for a straightforward assessment of the brain's energy budget from macroscopic measurements with minimal underlying

  4. Radical formation, chemical processing, and explosion of interstellar grains

    NASA Technical Reports Server (NTRS)

    Greenberg, J. M.

    1976-01-01

    The ultraviolet radiation in interstellar space is shown to create a sufficient steady-state density of free radicals in the grain mantle material consisting of oxygen, carbon, nitrogen, and hydrogen to satisfy the critical condition for initiation of chain reactions. The criterion for minimum critical particle size for maintaining the chain reaction is of the order of the larger grain sizes in a distribution satisfying the average extinction and polarization measures. The triggering of the explosion of interstellar grains leading to the ejection of complex interstellar molecules is shown to be most probable where the grains are largest and where radiation is suddenly introduced; i.e., in regions of new star formation. Similar conditions prevail at the boundaries between very dark clouds and H II regions. When the energy released by the chemical activity of the free radicals is inadequate to explode the grain, the resulting mantle material must consist of extremely large organic molecules which are much more resistant to the hostile environment of H II regions than the classical dirty-ice mantles made up of water, methane, and ammonia.

  5. Formation and Degradation of Beta-casomorphins in Dairy Processing.

    PubMed

    Nguyen, Duc Doan; Johnson, Stuart Keith; Busetti, Francesco; Solah, Vicky Ann

    2015-01-01

    Milk proteins including casein are sources of peptides with bioactivity. One of these peptides is beta-casomorphin (BCM) which belongs to a group of opioid peptides formed from β-casein variants. Beta-casomorphin 7 (BCM7) has been demonstrated to be enzymatically released from the A1 or B β-casein variant. Epidemiological evidence suggests the peptide BCM 7 is a risk factor for development of human diseases, including increased risk of type 1 diabetes and cardiovascular diseases but this has not been thoroughly substantiated by research studies. High performance liquid chromatography coupled to UV-Vis and mass spectrometry detection as well as enzyme-linked immunosorbent assay (ELISA) has been used to analyze BCMs in dairy products. BCMs have been detected in raw cow's milk and human milk and a variety of commercial cheeses, but their presence has yet to be confirmed in commercial yoghurts. The finding that BCMs are present in cheese suggests they could also form in yoghurt, but be degraded during yoghurt processing. Whether BCMs do form in yoghurt and the amount of BCM forming or degrading at different processing steps needs further investigation and possibly will depend on the heat treatment and fermentation process used, but it remains an intriguing unknown.

  6. Formation and Degradation of Beta-casomorphins in Dairy Processing

    PubMed Central

    Nguyen, Duc Doan; Johnson, Stuart Keith; Busetti, Francesco; Solah, Vicky Ann

    2015-01-01

    Milk proteins including casein are sources of peptides with bioactivity. One of these peptides is beta-casomorphin (BCM) which belongs to a group of opioid peptides formed from β-casein variants. Beta-casomorphin 7 (BCM7) has been demonstrated to be enzymatically released from the A1 or B β-casein variant. Epidemiological evidence suggests the peptide BCM 7 is a risk factor for development of human diseases, including increased risk of type 1 diabetes and cardiovascular diseases but this has not been thoroughly substantiated by research studies. High performance liquid chromatography coupled to UV-Vis and mass spectrometry detection as well as enzyme–linked immunosorbent assay (ELISA) has been used to analyze BCMs in dairy products. BCMs have been detected in raw cow's milk and human milk and a variety of commercial cheeses, but their presence has yet to be confirmed in commercial yoghurts. The finding that BCMs are present in cheese suggests they could also form in yoghurt, but be degraded during yoghurt processing. Whether BCMs do form in yoghurt and the amount of BCM forming or degrading at different processing steps needs further investigation and possibly will depend on the heat treatment and fermentation process used, but it remains an intriguing unknown. PMID:25077377

  7. Secondary organic aerosol formation through fog processing of VOCs

    NASA Astrophysics Data System (ADS)

    Herckes, P.; Hutchings, J. W.

    2010-07-01

    Volatile Organic Compounds (VOCs) including benzene, toluene, ethylbenzene and xylenes (BTEX) have been determined in highly concentrated amounts (>1 ug/L) in intercepted clouds in northern Arizona (USA). These VOCs are found in concentrations much higher than predicted by partitioning alone. The reactivity of BTEX in the fog/cloud aqueous phase was investigated through laboratory studies. BTEX species showed fast degradation in the aqueous phase in the presence of peroxides and light. Observed half-lives ranged from three and six hours, substantially shorter than the respective gas phase half-lives (several days). The observed reaction rates were on the order of 1 ppb/min but decreased substantially with increasing concentrations of organic matter (TOC). The products of BTEX oxidation reactions were analyzed using HPLC-UV and LCMS. The first generation of products identified included phenol and cresols which correspond to the hydroxyl-addition reaction to benzene and toluene. Upon investigating of multi-generational products, smaller, less volatile species are predominant although a large variety of products is found. Most reaction products have substantially lower vapor pressure and will remain in the particle phase upon droplet evaporation. The SOA generation potential of cloud and fog processing of BTEX was evaluated using simple calculations and showed that in ideal situations these reactions could add up to 9% of the ambient aerosol mass. In more conservative scenarios, the contribution of the processing of BTEX was around 1% of ambient aerosol concentrations. Overall, cloud processing of VOC has the potential to contribute to the atmospheric aerosol mass. However, the contribution will depend upon many factors such as the irradiation, organic matter content in the droplets and droplet lifetime.

  8. Stochastic processes in light-assisted nanoparticle formation

    NASA Astrophysics Data System (ADS)

    Naruse, Makoto; Liu, Yang; Nomura, Wataru; Yatsui, Takashi; Aida, Masaki; Kish, Laszlo B.; Ohtsu, Motoichi

    2012-05-01

    Recently, light-assisted nanofabrication have been introduced, such as the synthesis of quantum dots using photo-induced desorption that yields reduced size fluctuations or metal sputtering under light illumination resulting in self-organized, nanoparticle chains. The physical mechanisms have originally been attributed to material desorption or plasmon resonance effects. However, significant stochastic phenomena are also present that have not been explained yet. We introduce stochastic models taking account of the light-assisted processes that reproduce phenomenological characteristics consistent with the experimental observations.

  9. STARBURST-DRIVEN GALACTIC WINDS: FILAMENT FORMATION AND EMISSION PROCESSES

    SciTech Connect

    Cooper, Jackie L.; Bicknell, Geoffrey V.; Sutherland, Ralph S.; Bland-Hawthorn, Joss

    2009-09-20

    We have performed a series of three-dimensional simulations of the interaction of a supersonic wind with a nonspherical radiative cloud. These simulations are motivated by our recent three-dimensional model of a starburst-driven galactic wind interacting with an inhomogeneous disk, which shows that an optically emitting filament can be formed by the breakup and acceleration of a cloud into a supersonic wind. In this study, we consider the evolution of a cloud with two different geometries (fractal and spherical) and investigate the importance of radiative cooling on the cloud's survival. We have also undertaken a comprehensive resolution study in order to ascertain the effect of the assumed numerical resolution on the results. We find that the ability of the cloud to radiate heat is crucial for its survival, with a radiative cloud experiencing a lower degree of acceleration and having a higher relative Mach number to the flow than in the adiabatic case. This diminishes the destructive effect of the Kelvin-Helmholtz instability on the cloud. While an adiabatic cloud is destroyed over a short period of time, a radiative cloud is broken up via the Kelvin-Helmholtz instability into numerous small, dense cloudlets, which are drawn into the flow to form a filamentary structure. The degree of fragmentation is highly dependent on the resolution of the simulation, with the number of cloudlets formed increasing as the Kelvin-Helmholtz instability is better resolved. Nevertheless, there is a clear qualitative trend, with the filamentary structure still persistent at high resolution. The geometry of the cloud affects the speed at which the cloud fragments; a wind more rapidly breaks up the cloud in regions of least density. A cloud with a more inhomogeneous density distribution fragments faster than a cloud with a more uniform structure (e.g., a sphere). We confirm the mechanism behind the formation of the Halpha emitting filaments found in our global simulations of a

  10. Recovery and regeneration of spent MHD seed material by the formate process

    DOEpatents

    Sheth, Atul C.; Holt, Jeffrey K.; Rasnake, Darryll G.; Solomon, Robert L.; Wilson, Gregory L.; Herrigel, Howard R.

    1991-01-01

    The specification discloses a spent seed recovery and regeneration process for an MHM power plant employing an alkali metal salt seed material such as potassium salt wherein the spent potassium seed in the form of potassium sulfate is collected from the flue gas and reacted with calcium hydroxide and carbon monoxide in an aqueous solution to cause the formation of calcium sulfate and potassium formate. The pH of the solution is adjusted to supress formation of formic acid and to promote precipitation of any dissolved calcium salts. The solution containing potassium formate is then employed to provide the potassium salt in the form of potassium formate or, optionally, by heating the potassium formate under oxidizing conditions to convert the potassium formate to potassium carbonate.

  11. Recovery and regeneration of spent MHD seed material by the formate process

    DOEpatents

    Sheth, A.C.; Holt, J.K.; Rasnake, D.G.; Solomon, R.L.; Wilson, G.L.; Herrigel, H.R.

    1991-10-15

    The specification discloses a spent seed recovery and regeneration process for an MHD power plant employing an alkali metal salt seed material such as potassium salt wherein the spent potassium seed in the form of potassium sulfate is collected from the flue gas and reacted with calcium hydroxide and carbon monoxide in an aqueous solution to cause the formation of calcium sulfate and potassium formate. The pH of the solution is adjusted to suppress formation of formic acid and to promote precipitation of any dissolved calcium salts. The solution containing potassium formate is then employed to provide the potassium salt in the form of potassium formate or, optionally, by heating the potassium formate under oxidizing conditions to convert the potassium formate to potassium carbonate. 5 figures.

  12. Geochemical constraints on magma formation and transport processes

    NASA Astrophysics Data System (ADS)

    Shorttle, O.; Antoshechkina, P. M.; Dasgupta, R.; Rudge, J. F.; Asimow, P. D.

    2015-12-01

    Primitive basalts provide an invaluable probe of the mantle's thermo-chemical structure. What these samples show is that the Earth's interior is widely variable in its trace element, isotopic and even major element composition, on the km to the hemispherical scale. This heterogeneity has profound implications for not only the history of the solid Earth, but the oceans and atmosphere as well, as it represents ~4 billions of years of elemental transport back into the mantle via subduction recycling of oceanic crustal to mantle sections. Reconstructing planetary evolution through the volcanic record of mantle composition is therefore a primary aim of igneous geochemistry. However, between the solid mantle and our chemical analyses lie a series of melt generation, aggregation and transport processes, themselves poorly understood, that are potentially critical in controlling the amplitude and style of chemical heterogeneity preserved in an erupted basalt. If these processes are also sensitive to mantle potential temperature, the degree of melting and the presence of lithological heterogeneity, then the geochemical record may not only be biased as a whole, but biased in a relative sense between different geodynamic settings: such a dichotomy may be represented by ocean islands and mid-ocean ridges. Here we combine observational and modelling approaches to understand how varying conditions of melt generation and transport affect basalt chemical variability. Focusing first on Iceland, we combine new and existing melt inclusion data to investigate how chemical variability may be controlled by tectonic parameters (on versus off rift) and source enrichment. We find that on Iceland the key parameter controlling variability is enrichment, with the most enriched basalts preserving diminished variability compared with more depleted eruptions. However, on a larger scale enriched sources preserve the greatest variability: we see this both in terms of the greater variability of

  13. [The effect of encoding on false memory: examination on levels of processing and list presentation format].

    PubMed

    Hamajima, Hideki

    2004-04-01

    Using the Deese/Roediger-McDermott paradigm, the effects of lists presentation format (blocked/random) and levels of processing of critical nonpresented lures were examined. A levels-of-processing effect in a blocked presentation order was not observed for lures. Rates of false recognition and remember judgments for lures in a shallow level of processing were significantly lower than those in a deep level of processing when items from various themes were inter-mixed instead of blocked. Results showed an interaction between levels of processing and list presentation format. It is thus concluded that encoding of each word and whole list should be both considered in understanding false memory.

  14. Wavefront curvature limitations and compensation to polar format processing for synthetic aperture radar images.

    SciTech Connect

    Doerry, Armin Walter

    2006-01-01

    Limitations on focused scene size for the Polar Format Algorithm (PFA) for Synthetic Aperture Radar (SAR) image formation are derived. A post processing filtering technique for compensating the spatially variant blurring in the image is examined. Modifications to this technique to enhance its robustness are proposed.

  15. Preparedness Formation of the Future Vocational Education Teachers to Occupational Adaptation under Conditions of Globalization Processes

    ERIC Educational Resources Information Center

    Sushentseva, Liliya

    2014-01-01

    The problem of the preparedness formation of future teachers of vocational training to the professional adaptation under conditions of globalization processes in society is considered. The analysis of scientific and educational literature devoted to the study of occupational adaptation and preparedness formation of specialists to it is carried…

  16. Comparison of different procedures to stabilize biogas formation after process failure in a thermophilic waste digestion system: influence of aggregate formation on process stability.

    PubMed

    Kleyböcker, A; Liebrich, M; Kasina, M; Kraume, M; Wittmaier, M; Würdemann, H

    2012-06-01

    Following a process failure in a full-scale biogas reactor, different counter measures were undertaken to stabilize the process of biogas formation, including the reduction of the organic loading rate, the addition of sodium hydroxide (NaOH), and the introduction of calcium oxide (CaO). Corresponding to the results of the process recovery in the full-scale digester, laboratory experiments showed that CaO was more capable of stabilizing the process than NaOH. While both additives were able to raise the pH to a neutral milieu (pH>7.0), the formation of aggregates was observed particularly when CaO was used as the additive. Scanning electron microscopy investigations revealed calcium phosphate compounds in the core of the aggregates. Phosphate seemed to be released by phosphorus-accumulating organisms, when volatile fatty acids accumulated. The calcium, which was charged by the CaO addition, formed insoluble salts with long chain fatty acids, and caused the precipitation of calcium phosphate compounds. These aggregates were surrounded by a white layer of carbon rich organic matter, probably consisting of volatile fatty acids. Thus, during the process recovery with CaO, the decrease in the amount of accumulated acids in the liquid phase was likely enabled by (1) the formation of insoluble calcium salts with long chain fatty acids, (2) the adsorption of volatile fatty acids by the precipitates, (3) the acid uptake by phosphorus-accumulating organisms and (4) the degradation of volatile fatty acids in the aggregates. Furthermore, this mechanism enabled a stable process performance after re-activation of biogas production. In contrast, during the counter measure with NaOH aggregate formation was only minor resulting in a rapid process failure subsequent the increase of the organic loading rate.

  17. Comparison of different procedures to stabilize biogas formation after process failure in a thermophilic waste digestion system: Influence of aggregate formation on process stability

    SciTech Connect

    Kleyboecker, A.; Liebrich, M.; Kasina, M.; Kraume, M.; Wittmaier, M.; Wuerdemann, H.

    2012-06-15

    Highlights: Black-Right-Pointing-Pointer Mechanism of process recovery with calcium oxide. Black-Right-Pointing-Pointer Formation of insoluble calcium salts with long chain fatty acids and phosphate. Black-Right-Pointing-Pointer Adsorption of VFAs by the precipitates resulting in the formation of aggregates. Black-Right-Pointing-Pointer Acid uptake and phosphate release by the phosphate-accumulating organisms. Black-Right-Pointing-Pointer Microbial degradation of volatile fatty acids in the aggregates. - Abstract: Following a process failure in a full-scale biogas reactor, different counter measures were undertaken to stabilize the process of biogas formation, including the reduction of the organic loading rate, the addition of sodium hydroxide (NaOH), and the introduction of calcium oxide (CaO). Corresponding to the results of the process recovery in the full-scale digester, laboratory experiments showed that CaO was more capable of stabilizing the process than NaOH. While both additives were able to raise the pH to a neutral milieu (pH > 7.0), the formation of aggregates was observed particularly when CaO was used as the additive. Scanning electron microscopy investigations revealed calcium phosphate compounds in the core of the aggregates. Phosphate seemed to be released by phosphorus-accumulating organisms, when volatile fatty acids accumulated. The calcium, which was charged by the CaO addition, formed insoluble salts with long chain fatty acids, and caused the precipitation of calcium phosphate compounds. These aggregates were surrounded by a white layer of carbon rich organic matter, probably consisting of volatile fatty acids. Thus, during the process recovery with CaO, the decrease in the amount of accumulated acids in the liquid phase was likely enabled by (1) the formation of insoluble calcium salts with long chain fatty acids, (2) the adsorption of volatile fatty acids by the precipitates, (3) the acid uptake by phosphorus-accumulating organisms and (4

  18. Deciphering skeletal patterning: clues from the limb.

    PubMed

    Mariani, Francesca V; Martin, Gail R

    2003-05-15

    Even young children can distinguish a Tyrannosaurus rex from a Brontosaurus by observing differences in bone size, shape, number and arrangement, that is, skeletal pattern. But despite our extensive knowledge about cartilage and bone formation per se, it is still largely a mystery how skeletal pattern is established. Much of what we do know has been learned from studying limb development in chicken and mouse embryos. Based on the data from such studies, models for how limb skeletal pattern is established have been proposed and continue to be hotly debated.

  19. Deciphering Martian climatic history using returned samples

    NASA Technical Reports Server (NTRS)

    Paige, D. A.; Krieger, D. B.; Brigham, C. A.

    1988-01-01

    By necessity, a Mars sample return mission must sample the upper few meters of the Martian surface. This material was subjected to a wide variety of physical processes. Presently, the most important processes are believed to be wind-driven erosion and deposition, and water ice accumulation at higher latitudes. A sample return mission represents an opportunity to better understand and quantify these important geological processes. By obtaining sample cores at key locations, it may be possible to interpret much of recent Martian climatic history.

  20. Deciphering spectral fingerprints of habitable exoplanets.

    PubMed

    Kaltenegger, Lisa; Selsis, Frank; Fridlund, Malcolm; Lammer, Helmut; Beichman, Charles; Danchi, William; Eiroa, Carlos; Henning, Thomas; Herbst, Tom; Léger, Alain; Liseau, René; Lunine, Jonathan; Paresce, Francesco; Penny, Alan; Quirrenbach, Andreas; Röttgering, Huub; Schneider, Jean; Stam, Daphne; Tinetti, Giovanna; White, Glenn J

    2010-01-01

    We discuss how to read a planet's spectrum to assess its habitability and search for the signatures of a biosphere. After a decade rich in giant exoplanet detections, observation techniques have advanced to a level where we now have the capability to find planets of less than 10 Earth masses (M(Earth)) (so-called "super Earths"), which may be habitable. How can we characterize those planets and assess whether they are habitable? This new field of exoplanet search has shown an extraordinary capacity to combine research in astrophysics, chemistry, biology, and geophysics into a new and exciting interdisciplinary approach to understanding our place in the Universe. The results of a first-generation mission will most likely generate an amazing scope of diverse planets that will set planet formation, evolution, and our planet into an overall context.

  1. Formation kinetics of potential fermentation inhibitors in a steam explosion process of corn straw.

    PubMed

    Zhang, Yuzhen; Wang, Lan; Chen, Hongzhang

    2013-01-01

    The weak acids, furan derivatives, and phenolic compounds formed during lignocellulose pretreatment are potential inhibitors of subsequent enzymatic and microbial processes. In this work, the effects of the steam explosion process on the formation of weak acids, furan derivatives, and phenolic compounds were explored. The correlations of different steam explosion conditions and formation kinetics of degradation products showed that the formation of weak acids and furan derivatives was in the first-order reactions, which are expressed as [Formula: see text]. The formation of weak acids and furan derivatives increases with pretreatment temperature and time. On the other hand, the formation of phenolic compounds showed typical characteristics of continuous reaction, expressed as [Formula: see text]. The formation was affected by the active energies in two stages, temperature and time, and thus existed at extreme value. This work revealed the formation rules of weak acids, furan derivatives, and phenolic compounds in a steam explosion process and provided theoretical guidelines for improving the process and limiting the production of certain inhibitors.

  2. Deciphering Galactic Hydrogen with 21-SPONGE

    NASA Astrophysics Data System (ADS)

    Murray, Claire; Stanimirovic, Snezana; Goss, Miller; Heiles, Carl E.; Miller Dickey, John; Lindner, Robert; Babler, Brian L.

    2017-01-01

    Neutral hydrogen (HI) in the interstellar medium (ISM) is crucial to the life cycles of galaxies. The balance between disparate phases of HI -- including the cold neutral (CNM) and warm neutral (WNM) medium -- governs the formation of dense, star-forming material, and reflects the nature of feedback in galaxies. To probe the multi-phase structure of HI, we present results from 21-SPONGE: the largest and most sensitive survey for Galactic HI absorption ever at the Karl G. Jansky Very Large Array (VLA). Complemented by HI emission from the Arecibo Observatory, 21-SPONGE is uniquely sensitive to CNM and WNM temperatures from 10-104 K and column densities from 1018-1022 cm-2. Despite our unprecedented sensitivity, the maximum temperature we detect for individual spectral lines is Ts~1500 K, although stacking analysis of 21-SPONGE absorption lines indicates the presence of pervasive, high-Ts WNM population with Ts~7000 K. To understand the physics underlying these results, we developed Autonomous Gaussian Decomposition (AGD), a Python-based tool for efficiently and objectively analyzing spectral lines. By applying AGD to 21-SPONGE and 1000s of synthetic HI spectra from 3D numerical simulations, we correct our measurements for completeness and observational biases. We further prove that we can successfully recover the temperatures and densities of real clouds along simulated lines of sight. In addition, we show that absorption line shapes are sensitive to the strength and topology of the Lyman alpha radiation field and its role in HI excitation, which are poorly-constrained yet important for understanding the energy balance of the ISM. Our results are among the first to statistically quantify the success of observational methods at reproducing true HI properties, and represent crucial steps towards understanding the role of HI in star formation.

  3. [A sheet for deciphering the cries of hospitalized elderly patients].

    PubMed

    Gomas, Jean-Marie; Tribout, Didier; Knorreck, Fanny; Denis, Michel; Petrognani, Annie; Sales, Elodie

    2014-01-01

    Crying out is not an insignificant act and it is important to fight against this misconception. Any caregiver can be confronted with this phenomenon with elderly hospitalised patients. Their cries must be understood, analysed and taken into account as they correspond to a particular situation experienced by the elderly patient. There are tools to help caregivers diagnose and reflect on this clinical context. This article presents the example of an interpretation sheet which can help caregivers decipher patients' cries.

  4. The experimental production of matrix lumps within chondrules: Evidence of post-formational processes

    NASA Technical Reports Server (NTRS)

    Connolly, Harold C., Jr.; Hewins, Roger H.

    1993-01-01

    The processes that acted upon chondrules after their formation are as important clues to the nature of the early solar nebula as are the exact processes that formed the chondrules. Recent experiments have studied the rim forming processes and the effects the processes have on chondrules. We present below information on how matrix inclusions found within chondrules may have been formed and the potential usefulness of this information.

  5. Fast processing of digital imaging and communications in medicine (DICOM) metadata using multiseries DICOM format

    PubMed Central

    Ismail, Mahmoud; Philbin, James

    2015-01-01

    Abstract. The digital imaging and communications in medicine (DICOM) information model combines pixel data and its metadata in a single object. There are user scenarios that only need metadata manipulation, such as deidentification and study migration. Most picture archiving and communication system use a database to store and update the metadata rather than updating the raw DICOM files themselves. The multiseries DICOM (MSD) format separates metadata from pixel data and eliminates duplicate attributes. This work promotes storing DICOM studies in MSD format to reduce the metadata processing time. A set of experiments are performed that update the metadata of a set of DICOM studies for deidentification and migration. The studies are stored in both the traditional single frame DICOM (SFD) format and the MSD format. The results show that it is faster to update studies’ metadata in MSD format than in SFD format because the bulk data is separated in MSD and is not retrieved from the storage system. In addition, it is space efficient to store the deidentified studies in MSD format as it shares the same bulk data object with the original study. In summary, separation of metadata from pixel data using the MSD format provides fast metadata access and speeds up applications that process only the metadata. PMID:26158117

  6. Fast processing of digital imaging and communications in medicine (DICOM) metadata using multiseries DICOM format.

    PubMed

    Ismail, Mahmoud; Philbin, James

    2015-04-01

    The digital imaging and communications in medicine (DICOM) information model combines pixel data and its metadata in a single object. There are user scenarios that only need metadata manipulation, such as deidentification and study migration. Most picture archiving and communication system use a database to store and update the metadata rather than updating the raw DICOM files themselves. The multiseries DICOM (MSD) format separates metadata from pixel data and eliminates duplicate attributes. This work promotes storing DICOM studies in MSD format to reduce the metadata processing time. A set of experiments are performed that update the metadata of a set of DICOM studies for deidentification and migration. The studies are stored in both the traditional single frame DICOM (SFD) format and the MSD format. The results show that it is faster to update studies' metadata in MSD format than in SFD format because the bulk data is separated in MSD and is not retrieved from the storage system. In addition, it is space efficient to store the deidentified studies in MSD format as it shares the same bulk data object with the original study. In summary, separation of metadata from pixel data using the MSD format provides fast metadata access and speeds up applications that process only the metadata.

  7. DECIPHER, a search-based approach to chimera identification for 16S rRNA sequences.

    PubMed

    Wright, Erik S; Yilmaz, L Safak; Noguera, Daniel R

    2012-02-01

    DECIPHER is a new method for finding 16S rRNA chimeric sequences by the use of a search-based approach. The method is based upon detecting short fragments that are uncommon in the phylogenetic group where a query sequence is classified but frequently found in another phylogenetic group. The algorithm was calibrated for full sequences (fs_DECIPHER) and short sequences (ss_DECIPHER) and benchmarked against WigeoN (Pintail), ChimeraSlayer, and Uchime using artificially generated chimeras. Overall, ss_DECIPHER and Uchime provided the highest chimera detection for sequences 100 to 600 nucleotides long (79% and 81%, respectively), but Uchime's performance deteriorated for longer sequences, while ss_DECIPHER maintained a high detection rate (89%). Both methods had low false-positive rates (1.3% and 1.6%). The more conservative fs_DECIPHER, benchmarked only for sequences longer than 600 nucleotides, had an overall detection rate lower than that of ss_DECIPHER (75%) but higher than those of the other programs. In addition, fs_DECIPHER had the lowest false-positive rate among all the benchmarked programs (<0.20%). DECIPHER was outperformed only by ChimeraSlayer and Uchime when chimeras were formed from closely related parents (less than 10% divergence). Given the differences in the programs, it was possible to detect over 89% of all chimeras with just the combination of ss_DECIPHER and Uchime. Using fs_DECIPHER, we detected between 1% and 2% additional chimeras in the RDP, SILVA, and Greengenes databases from which chimeras had already been removed with Pintail or Bellerophon. DECIPHER was implemented in the R programming language and is directly accessible through a webpage or by downloading the program as an R package (http://DECIPHER.cee.wisc.edu).

  8. Integrating Individual Learning Processes and Organizational Knowledge Formation: Foundational Determinants for Organizational Performance

    ERIC Educational Resources Information Center

    Song, Ji Hoon; Chermack, Thomas J.; Kim, Hong Min

    2008-01-01

    This research examined the link between learning processes and knowledge formation through an integrated literature review from both academic and practical viewpoints. Individuals' learning processes and organizational knowledge creation were reviewed by means of theoretical and integrative analysis based on a lack of empirical research on the…

  9. The KEGG resource for deciphering the genome.

    PubMed

    Kanehisa, Minoru; Goto, Susumu; Kawashima, Shuichi; Okuno, Yasushi; Hattori, Masahiro

    2004-01-01

    A grand challenge in the post-genomic era is a complete computer representation of the cell and the organism, which will enable computational prediction of higher-level complexity of cellular processes and organism behavior from genomic information. Toward this end we have been developing a knowledge-based approach for network prediction, which is to predict, given a complete set of genes in the genome, the protein interaction networks that are responsible for various cellular processes. KEGG at http://www.genome.ad.jp/kegg/ is the reference knowledge base that integrates current knowledge on molecular interaction networks such as pathways and complexes (PATHWAY database), information about genes and proteins generated by genome projects (GENES/SSDB/KO databases) and information about biochemical compounds and reactions (COMPOUND/GLYCAN/REACTION databases). These three types of database actually represent three graph objects, called the protein network, the gene universe and the chemical universe. New efforts are being made to abstract knowledge, both computationally and manually, about ortholog clusters in the KO (KEGG Orthology) database, and to collect and analyze carbohydrate structures in the GLYCAN database.

  10. Deciphering Neural Codes of Memory during Sleep.

    PubMed

    Chen, Zhe; Wilson, Matthew A

    2017-04-05

    Memories of experiences are stored in the cerebral cortex. Sleep is critical for the consolidation of hippocampal memory of wake experiences into the neocortex. Understanding representations of neural codes of hippocampal-neocortical networks during sleep would reveal important circuit mechanisms in memory consolidation and provide novel insights into memory and dreams. Although sleep-associated ensemble spike activity has been investigated, identifying the content of memory in sleep remains challenging. Here we revisit important experimental findings on sleep-associated memory (i.e., neural activity patterns in sleep that reflect memory processing) and review computational approaches to the analysis of sleep-associated neural codes (SANCs). We focus on two analysis paradigms for sleep-associated memory and propose a new unsupervised learning framework ('memory first, meaning later') for unbiased assessment of SANCs.

  11. Surfactant process for promoting gas hydrate formation and application of the same

    DOEpatents

    Rogers, Rudy E.; Zhong, Yu

    2002-01-01

    This invention relates to a method of storing gas using gas hydrates comprising forming gas hydrates in the presence of a water-surfactant solution that comprises water and surfactant. The addition of minor amounts of surfactant increases the gas hydrate formation rate, increases packing density of the solid hydrate mass and simplifies the formation-storage-decomposition process of gas hydrates. The minor amounts of surfactant also enhance the potential of gas hydrates for industrial storage applications.

  12. Formation of disinfection by-products in the ultraviolet/chlorine advanced oxidation process.

    PubMed

    Wang, Ding; Bolton, James R; Andrews, Susan A; Hofmann, Ron

    2015-06-15

    Disinfection by-product (DBP) formation may be a concern when applying ultraviolet light and free chlorine (UV/chlorine) as an advanced oxidation process (AOP) for drinking water treatment, due to typically large chlorine doses (e.g. 5-10 mg L(-1) as free chlorine). A potential mitigating factor is the low chlorine contact times for this AOP treatment (e.g. seconds). Full-scale and pilot-scale test results showed minimal trihalomethane (THM) and haloacetic acid (HAA) formation during UV/chlorine treatment, while dichloroacetonitrile (DCAN) and bromochloroacetonitrile (BCAN) were produced rapidly. Adsorbable organic halide (AOX) formation was significant when applying the UV/chlorine process in water that had not been previously chlorinated, while little additional formation was observed in prechlorinated water. Chlorine photolysis led to chlorate and bromate formation, equivalent to approximately 2-17% and 0.01-0.05% of the photolyzed chlorine, respectively. No perchlorate or chlorite formation was observed. During simulated secondary disinfection of AOP-treated water, DBP formation potential for THMs, HAAs, HANs, and AOX was observed to increase approximately to the same extent as was observed for pretreatment using the more common AOP of UV combined with hydrogen peroxide (UV/H2O2).

  13. Comparison of processes of river delta formation on Titan and Earth

    NASA Astrophysics Data System (ADS)

    Witek, P. P.; Czechowski, L. L.

    2014-04-01

    The Cassini-Huygens mission has revealed the existence of hydrocarbon lakes and river valleys on Titan. We simulate processes of sediment transport and deposition on Titan and compare them with analogous processes on Earth and Mars, with several possible compositions of the liquid and the sediments. Our results show many similarities between the processes, but also some differences concerning e.g. the time scale of formation of depositional complexes.

  14. Deciphering the role of exosomes in tuberculosis.

    PubMed

    Kruh-Garcia, Nicole A; Wolfe, Lisa M; Dobos, Karen M

    2015-01-01

    Exosomes were originally described as small vesicles released from reticulocytes during the maturation process. These 40-200 nm microvesicles were hypothesized to be a mechanism for the removal of membrane proteins in lieu of intracellular degradation by Harding et al. (1984) and Johnstone et al. (1987) [1,2]. Exosomes can be distinguished from other extracellular vesicles (ectosomes, apoptotic blebs) based on their size and the protein indicators intercalated in their membrane (also, linking their derivation from the endocytic pathway) by Simpson (2012) [3]. The exact role which exosomes play in cell-to-cell communication and immune modulation is a topic of intense study. However, the focus of most reports has been directed towards discovering aberrations in exosomal protein and RNA content linked to disease onset and progression, and also primarily related to cancer. Nonetheless, exosomes are now documented to be released from a wide variety of cell types by Mathivanan et al. (2012), Simpson et al. (2012) and Kalra et al. (2012) [4-6] and have been isolated from all bodily fluids; thus, exosomes are an excellent source of biomarkers. Here we describe the discoveries related to the role exosomes play in tuberculosis disease, as well as translational work in vaccine development and how circulation of these dynamic vesicles can be harnessed for diagnostic purposes.

  15. Deciphering arboviral emergence within insular ecosystems.

    PubMed

    Tortosa, Pablo; Pascalis, Hervé; Guernier, Vanina; Cardinale, Eric; Le Corre, Matthieu; Goodman, Steven M; Dellagi, Koussay

    2012-08-01

    The spatial dynamics of zoonotic arthropod-borne viruses is a fashionable though challenging topic. Inter-human local transmission of a given arbovirus during an outbreak and its spread over large distances are considered as key parameters of emergence. Here, we suggest that insular ecosystems provide ideal natural "laboratory" conditions to uncouple local transmission from long distance spread, and differentiate these two processes. Due to geographic isolation, often-limited land surface area and relatively homogenous ecosystems, oceanic islands display low species richness and often-high levels of endemism. These aspects provide the means for comprehensive entomological surveys and investigations of original host/pathogen interactions. In addition, islands are interconnected through discrete anthropogenic and non-anthropogenic exchanges: whilst islands maintain a substantial level of human and domestic animal exchange with other neighbouring or distant territories, they also comprise dispersal and migratory pathways of volant organisms (insects, birds and bats). Hence, both anthropogenic and non-anthropogenic exchanges in island systems are easier to identify and investigate than in continuous, continental systems. Finally, island ecosystems tend to be notably simpler, more prone to invasive taxa and, therefore, easier to document the colonization or displacement of vector species. These different aspects are presented and overlaid upon the spread of arboviruses within two distinct insular systems: islands of Polynesia and the south-western Indian Ocean. The former have been repeatedly affected by Dengue fever epidemics, while the latter recently suffered four successive epidemics, probably of east African origin, three of which involved the emerging viruses Chikungunya, Rift Valley and Dengue fever. Here, we review some new insights into arboviral spread and evolution associated with investigations that followed these epidemics, as well as several aspects that

  16. Raman and terahertz spectroscopical investigation of cocrystal formation process of piracetam and 3-hydroxybenzoic acid.

    PubMed

    Du, Yong; Zhang, Huili; Xue, Jiadan; Fang, Hongxia; Zhang, Qi; Xia, Yi; Li, Yafang; Hong, Zhi

    2015-03-15

    Cocrystallization can improve physical and chemical properties of active pharmaceutical ingredient, and this feature has great potential in pharmaceutical development. In this study, the cocrystal of piracetam and 3-hydroxybenzoic acid under grinding condition has been characterized by Raman and terahertz spectroscopical techniques. The major vibrational modes of individual starting components and cocrystal are obtained and assigned. Spectral results show that the vibrational modes of the cocrystal are different from those of the corresponding parent materials. The dynamic process of such pharmaceutical cocrystal formation has also been monitored directly with Raman and THz spectra. The formation rate is pretty fast in first several 20 min grinding time, and then it becomes slow. After ∼35 min, such process has been almost completed. These results offer us the unique means and benchmark for characterizing the cocrystal conformation from molecule-level and also provide us rich information about the reaction dynamic during cocrystal formation process in pharmaceutical fields.

  17. Raman and terahertz spectroscopical investigation of cocrystal formation process of piracetam and 3-hydroxybenzoic acid

    NASA Astrophysics Data System (ADS)

    Du, Yong; Zhang, Huili; Xue, Jiadan; Fang, Hongxia; Zhang, Qi; Xia, Yi; Li, Yafang; Hong, Zhi

    2015-03-01

    Cocrystallization can improve physical and chemical properties of active pharmaceutical ingredient, and this feature has great potential in pharmaceutical development. In this study, the cocrystal of piracetam and 3-hydroxybenzoic acid under grinding condition has been characterized by Raman and terahertz spectroscopical techniques. The major vibrational modes of individual starting components and cocrystal are obtained and assigned. Spectral results show that the vibrational modes of the cocrystal are different from those of the corresponding parent materials. The dynamic process of such pharmaceutical cocrystal formation has also been monitored directly with Raman and THz spectra. The formation rate is pretty fast in first several 20 min grinding time, and then it becomes slow. After ∼35 min, such process has been almost completed. These results offer us the unique means and benchmark for characterizing the cocrystal conformation from molecule-level and also provide us rich information about the reaction dynamic during cocrystal formation process in pharmaceutical fields.

  18. Aerosol effect on the warm rain formation process: Satellite observations and modeling

    NASA Astrophysics Data System (ADS)

    Suzuki, Kentaroh; Stephens, Graeme L.; Lebsock, Matthew D.

    2013-01-01

    This study demonstrates how aerosols influence the liquid precipitation formation process. This demonstration is provided by the combined use of satellite observations and global high-resolution model simulations. Methodologies developed to examine the warm cloud microphysical processes are applied to both multi-sensor satellite observations and aerosol-coupled global cloud-resolving model (GCRM) results to illustrate how the warm rain formation process is modulated under different aerosol conditions. The observational analysis exhibits process-scale signatures of rain suppression due to increased aerosols, providing observational evidence of the aerosol influence on precipitation. By contrast, the corresponding statistics obtained from the model show a much faster rain formation even for polluted aerosol conditions and much weaker reduction of precipitation in response to aerosol increase. It is then shown that this reduced sensitivity points to a fundamental model bias in the warm rain formation process that in turn biases the influence of aerosol on precipitation. A method of improving the model bias is introduced in the context of a simplified single-column model (SCM) that represents the cloud-to-rain water conversion process in a manner similar to the original GCRM. Sensitivity experiments performed by modifying the model assumptions in the SCM and their comparisons to satellite statistics both suggest that the auto-conversion scheme has a critical role in determining the precipitation response to aerosol perturbations and also provide a novel way of constraining key parameters in the auto-conversion schemes of global models.

  19. Mechanism of hologram formation in fixation-free rehalogenating bleaching processes

    NASA Astrophysics Data System (ADS)

    Neipp, Cristian; Pascual, Inmaculada; Belendez, Augusto

    2002-07-01

    The mechanism of hologram formation in fixation-free rehalogenating bleaching processes have been treated by different authors. The experiments carried out on Agfa 8E75 HD plates led to the conclusion that material transfer from the exposed to the unexposed zones is the main mechanism under the process. We present a simple model that explains the mechanism of hologram formation inside the emulsion. Also quantitative data obtained using both Agfa 8E75 HD and Slavich PFG-01 fine-grained red-sensitive emulsions are given and good agreement between theory and experiments are found.

  20. Relational processes and identity formation in adolescence: the example of A Separate Peace.

    PubMed

    Flum, H; Porton, H

    1995-11-01

    The process of identity formation in adolescence, specifically, the relational context of identity formation, is examined through the prism of the story of an adolescent boy's development during the Second World War at a boarding school in New Hampshire, USA--John Knowles's A Separate Peace. The discussion focuses on mirroring, on the adolescent's need to be validated and the simultaneous fear of transparency, and on idealization and deidealization. Using the book as a narrative example of the transformation of connections that are essential to the process of development, the authors discuss the complexity of male adolescent growth.

  1. Deciphering the Adaptive Immune Response to Ovarian Cancer

    DTIC Science & Technology

    2014-10-01

    Weinstein JN, Collisson EA, Mills GB, Shaw KR, Ozenberger BA, Ellrott K, Shmulevich I, Sander C, Stuart JM. The Cancer Genome Atlas Pan-Cancer analysis...Holt, Ph.D., John Webb Ph.D., Peter Watson, M.D. Title of Project: Deciphering the Adaptive Immune Response to Ovarian Cancer INTRODUCTION...Cherniack AD, Akbani R, Liu Y, Shen H, Robertson AG, Pashtan I, Shen R, Benz CC, Yau C, Laird PW, Ding L, Zhang W, Mills GB, Kucherlapati R, Mardis ER

  2. XAFS studies of monodisperse Au nanoclusters formation in the etching process

    NASA Astrophysics Data System (ADS)

    Yang, Lina; Huang, Ting; Liu, Wei; Bao, Jie; Huang, Yuanyuan; Cao, Yuanjie; Yao, Tao; Sun, Zhihu; Wei, Shiqiang

    2016-05-01

    Understanding the formation mechanism of gold nanoclusters is essential to the development of their synthetic chemistry. Here, by using x-ray absorption fine-structure (XAFS) spectroscopy, UV-Vis and MS spectra, the formation process of monodisperse Au13 nanoclusters is investigated. We find that a critical step involving the formation of smaller Au8-Au11 metastable intermediate clusters induced by the HCl + HSR etching of the polydisperse Aun precursor clusters occurs firstly. Then these intermediate species undergo a size-growth to Au13 cores, followed by a slow structure rearrangement to reach the final stable structure. This work enriches the understanding of cluster formation chemistry and may guide the way towards the design and the controllable synthesis of nanoclusters.

  3. The phosphorylation state of neuronal processes determines growth cone formation after neuronal injury.

    PubMed

    Geddis, Matthew S; Rehder, Vincent

    2003-10-15

    Growth cones are essential for neuronal pathfinding during embryonic development and again after injury, when they aid in neuronal regeneration. This study was aimed at investigating the role of kinases in the earliest events in neuronal regeneration, namely, the formation of new growth cones from injured neuronal processes. Neurites of identified snail neurons grown in vitro were severed, and the formation of growth cones was observed from the ends of such transected processes. Under control conditions, all neurites formed a new growth cone within 45 min of transection. In contrast, growth cone formation in the presence of a general kinase inhibitor, K252a, was significantly inhibited. Moreover, decreasing the phosphorylation state of neurites by activating protein phosphatases with C2-ceramide also reduced growth cone formation. Pharmacological analysis with specific kinase inhibitors suggested that targets of protein kinase C (PKC) and tyrosine kinase (PTK) phosphorylation control growth cone formation. Inhibition of PKC with calphostin C and cerebroside completely blocked growth cone formation, whereas the inhibition of PTK with erbstatin analog significantly reduced growth cone formation. In contrast, inhibitors of protein kinase A, protein kinase G, CaM-kinase II, myosin light-chain kinase, Rho kinase, and PI-3 kinase had little or no effect 45 min after transection. These results suggest that the transformation underlying the formation of a growth cone from an injured (transected) neurite stump is highly sensitive to the phosphorylation state of key target proteins. Therefore, injury-induced signaling events will determine the outcome of neuronal regeneration through their action on kinase and phosphatase activities.

  4. Investigation of cu-BTA complex formation during Cu chemical mechanical planarization process

    NASA Astrophysics Data System (ADS)

    Cho, Byoung-Jun; Shima, Shohei; Hamada, Satomi; Park, Jin-Goo

    2016-10-01

    The effect of Cu surface conditions on Cu-BTA complex formation was investigated using contact angle, electrochemical impedance spectroscopy, spectroscopic ellipsometry and XPS measurements which is of interest to Cu Chemical Mechanical Planarization (CMP) process. During Cu CMP process BTA is widely used as a corrosion inhibitor, reacts with Cu and forms a strong Cu-BTA complex. Thus, it is very essential to remove Cu-BTA complex during post-Cu CMP cleaning process as Cu-BTA complex causes severe problems such as particle contamination and watermark due to its hydrophobic nature. In this report, the Cu-BTA complex formation at various Cu surfaces (as received, pure Cu and Cu oxide) was investigated in order to understand its adsorption reaction and develop effective post-Cu CMP cleaning process.

  5. Quantifying fiber formation in meat analogs under high moisture extrusion using image processing

    NASA Astrophysics Data System (ADS)

    Ranasinghesagara, J.; Hsieh, F.; Yao, G.

    2005-11-01

    High moisture extrusion using twin-screw extruders shows great promise of producing meat analog products with vegetable proteins. The resulting products have well defined fiber formations; resemble real meat in both visual appearance and taste sensation. Developing reliable non-destructive techniques to quantify the textural properties of extrudates is important for quality control in the manufacturing process. In this study, we developed an image processing technique to automatically characterize sample fiber formation using digital imaging. The algorithm is based on statistical analysis of Hough transform. This objective method can be used as a standard method for evaluating other non-invasive methods. We have compared the fiber formation indices measured using this technique and a non-invasive fluorescence polarization method and obtained a high correlation.

  6. NMDA-R inhibition affects cellular process formation in Tilapia melanocytes; a model for pigmented adrenergic neurons in process formation and retraction.

    PubMed

    Ogundele, Olalekan Michael; Okunnuga, Adetokunbo Adedotun; Fabiyi, Temitope Deborah; Olajide, Olayemi Joseph; Akinrinade, Ibukun Dorcas; Adeniyi, Philip Adeyemi; Ojo, Abiodun Ayodele

    2014-06-01

    Parkinson's disease has long been described to be a product of dopamine and (or) melanin loss in the substanstia nigra (SN). Although most studies have focused on dopaminergic neurons, it is important to consider the role of pigment cells in the etiology of the disease and to create an in vitro live cell model for studies involving pigmented adrenergic cells of the SN in Parkinsonism. The Melanocytes share specific features with the pigmented adrenergic neurons as both cells are pigmented, contain adrenergic receptors and have cellular processes. Although the melanocyte cellular processes are relatively short and observable only when stimulated appropriately by epinephrine and other factors or molecules. This study employs the manipulation of N-Methyl-D-Aspartate Receptor (NMDA-R), a major receptor in neuronal development, in the process formation pattern of the melanocyte in order to create a suitable model to depict cellular process elongation and shortening in pigmented adrenergic cells. NMDA-R is an important glutamate receptor implicated in neurogenesis, neuronal migration, maturation and cell death, thus we investigated the role of NMDA-R potentiation by glutamate/KCN and its inhibition by ketamine in the behavior of fish scale melanocytes in vitro. This is aimed at establishing the regulatory role of NMDA-R in this cell type (melanocytes isolated form Tilapia) in a similar manner to what is observable in the mammalian neurons. In vitro live cell culture was prepared in modified Ringer's solution following which the cells were treated as follows; Control, Glutamate, Ketamine, Glutamate + Ketamine, KCN + Ketamine and KCN. The culture was maintained for 10 min and the changes were captured in 3D-Time frame at 0, 5 and 10 min for the control and 5, 7 and 10 min for each of the treatment category. Glutamate treatment caused formation of short cellular processes localized directly on the cell body while ketamine treatment (inhibition of NMDA-R) facilitated

  7. Vague-to-Crisp Dynamics of Percept Formation Modeled as Operant (Selectionist) Process

    DTIC Science & Technology

    2013-04-04

    framework with cognitive processing and the intentional neurodynamic cycle. Vague-to-crisp dynamics of percept formation m Approved for public...13: Supplementary Note © 2013 . Published in Cognitive Neurodynamics , Vol. Ed. 0 8, (1) (2013), (, (1). DoD Components reserve a royalty-free...operant (selectionist) process Roman Ilin, J un Zhang, Leonid Perlovsky & Robert Kozma Cognitive Neurodynamics ISSN 1871 4080 Cogn Neurodyn

  8. A System for Processing and Shelving Works of Mixed Media Format.

    ERIC Educational Resources Information Center

    Mann, Thomas J.

    1979-01-01

    A system for processing and shelving mixed media works is described, the advantage of which is its ability to make value judgments reflecting the author's intention as to which format is primary. Security needs, storage space problems, and desirability of maintaining browsing capabilities are also incorporated in this system. (Author/MBR)

  9. Embedded Formative Assessment and Classroom Process Quality: How Do They Interact in Promoting Science Understanding?

    ERIC Educational Resources Information Center

    Decristan, Jasmin; Klieme, Eckhard; Kunter, Mareike; Hochweber, Jan; Büttner, Gerhard; Fauth, Benjamin; Hondrich, A. Lena; Rieser, Svenja; Hertel, Silke; Hardy, Ilonca

    2015-01-01

    In this study we examine the interplay between curriculum-embedded formative assessment--a well-known teaching practice--and general features of classroom process quality (i.e., cognitive activation, supportive climate, classroom management) and their combined effect on elementary school students' understanding of the scientific concepts of…

  10. Influence of California-style black ripe olive processing on the formation of acrylamide.

    PubMed

    Charoenprasert, Suthawan; Mitchell, Alyson

    2014-08-27

    Methods used in processing California-style black ripe olives generate acrylamide. California-style black ripe olives contain higher levels of acrylamide (409.67 ± 42.60-511.91 ± 34.08 μg kg(-1)) as compared to California-style green ripe olives (44.02 ± 3.55-105.79 ± 22.01 μg kg(-1)), Greek olives (<1.42 μg kg(-1)), and Spanish olives (not detected), indicating that the higher temperatures used to sterilize the California-style green ripe and black ripe olives are required for acrylamide formation. Preprocessing brine storage influenced the formation of acrylamide in a time-dependent manner. Acrylamide increased during the first 30 days of storage. Longer brine storage times (>30 days) result in lower acrylamide levels in the finished product. The presence of calcium ions in the preprocessing brining solution results in higher levels of acrylamide in finished products. Air oxidation during lye processing and the neutralization of olives prior to sterilization significantly increase the formation of acrylamide in the finished products. Conversely, lye-processing decreases the levels of acrylamide in the final product. These results indicate that specific steps in the California-style black ripe olive processing may be manipulated to mitigate the formation of acrylamide in finished products.

  11. Processes Underlying Developmental Reversals in False-Memory Formation: Comment on Brainerd, Reyna, and Ceci (2008)

    ERIC Educational Resources Information Center

    Ghetti, Simona

    2008-01-01

    C. J. Brainerd, V. F. Reyna, and S. J. Ceci (2008) reviewed compelling evidence of developmental reversals in false-memory formation (i.e., younger children exhibit lower false-memory rates than do older children and adults) and proposed that this phenomenon depends on the development of gist processing (i.e., the ability to identify and process…

  12. Level of Processing Modulates the Neural Correlates of Emotional Memory Formation

    ERIC Educational Resources Information Center

    Ritchey, Maureen; LaBar, Kevin S.; Cabeza, Roberto

    2011-01-01

    Emotion is known to influence multiple aspects of memory formation, including the initial encoding of the memory trace and its consolidation over time. However, the neural mechanisms whereby emotion impacts memory encoding remain largely unexplored. The present study used a levels-of-processing manipulation to characterize the impact of emotion on…

  13. Formation Processes and Impacts of Reactive and Nonreactive Minerals in Permeable Reactive Barriers

    EPA Science Inventory

    Mineral precipitates in zero-valent iron PRBs can be classified by formation processes into three groups: 1) those that result from changes in chemical conditions (i.e., changes in pH, e.g., calcite); 2) those that are a consequence of microbial activity (i.e., sulfate reduction,...

  14. FORMATION PROCESSES AND CONSEQUENCES OF REACTIVE AND NON-REACTIVE MINERAL PRECIPITATES IN PERMEABLE REACTIVE BARRIERS

    EPA Science Inventory

    Mineral precipitates in zero-valent iron PRBs can be classified by formation processes into three groups: 1) those that result from changes in chemical conditions (i.e., change in pH, e.g., calcite); 2) those that are a consequence of microbial activity (i.e., sulfate reduction, ...

  15. An Exploration of the Process of Ideological Identity Formation in Young Rural Adolescents.

    ERIC Educational Resources Information Center

    Manners, Pamela A.; Smart, David J.

    This paper explores the process of identity formation as related to adolescents' level of moral development, race, sex, and family configuration. Ego identity was operationalized into four identity statuses based on an adolescent's reported degree of exploration and goal commitment in the areas of occupation, religion, politics, and philosophy…

  16. The Professional Competence Formation in the Training Process in Higher Educational Institution

    ERIC Educational Resources Information Center

    Burganova, Roza I.; Abdugalina, Sairan E.; Shaiheslyamova, Kazyna O.

    2016-01-01

    The article is devoted to the problem of professional competence formation in the specialists' training process at the university in contemporary socio-economic and socio-cultural conditions originating in the Republic of Kazakhstan. The emphasis is laid on new scientific and pedagogical approaches to its solution. Special attention is paid to the…

  17. Deciphering the evolutionary history of open and closed mitosis.

    PubMed

    Sazer, Shelley; Lynch, Michael; Needleman, Daniel

    2014-11-17

    The origin of the nucleus at the prokaryote-to-eukaryote transition represents one of the most important events in the evolution of cellular organization. The nuclear envelope encircles the chromosomes in interphase and is a selectively permeable barrier between the nucleoplasm and cytoplasm and an organizational scaffold for the nucleus. It remains intact in the 'closed' mitosis of some yeasts, but loses its integrity in the 'open' mitosis of mammals. Instances of both types of mitosis within two evolutionary clades indicate multiple evolutionary transitions between open and closed mitosis, although the underlying genetic changes that influenced these transitions remain unknown. A survey of the diversity of mitotic nuclei that fall between these extremes is the starting point from which to determine the physiologically relevant characteristics distinguishing open from closed mitosis and to understand how they evolved and why they are retained in present-day organisms. The field is now poised to begin addressing these issues by defining and documenting patterns of mitotic nuclear variation within and among species and mapping them onto a phylogenic tree. Deciphering the evolutionary history of open and closed mitosis will complement cell biological and genetic approaches aimed at deciphering the fundamental organizational principles of the nucleus.

  18. Envirotyping for deciphering environmental impacts on crop plants.

    PubMed

    Xu, Yunbi

    2016-04-01

    Global climate change imposes increasing impacts on our environments and crop production. To decipher environmental impacts on crop plants, the concept "envirotyping" is proposed, as a third "typing" technology, complementing with genotyping and phenotyping. Environmental factors can be collected through multiple environmental trials, geographic and soil information systems, measurement of soil and canopy properties, and evaluation of companion organisms. Envirotyping contributes to crop modeling and phenotype prediction through its functional components, including genotype-by-environment interaction (GEI), genes responsive to environmental signals, biotic and abiotic stresses, and integrative phenotyping. Envirotyping, driven by information and support systems, has a wide range of applications, including environmental characterization, GEI analysis, phenotype prediction, near-iso-environment construction, agronomic genomics, precision agriculture and breeding, and development of a four-dimensional profile of crop science involving genotype (G), phenotype (P), envirotype (E) and time (T) (developmental stage). In the future, envirotyping needs to zoom into specific experimental plots and individual plants, along with the development of high-throughput and precision envirotyping platforms, to integrate genotypic, phenotypic and envirotypic information for establishing a high-efficient precision breeding and sustainable crop production system based on deciphered environmental impacts.

  19. Deciphering host resistance and pathogen virulence: the Arabidopsis/Pseudomonas interaction as a model.

    PubMed

    Quirino, Betania F; Bent, Andrew F

    2003-11-01

    SUMMARY The last decade has witnessed steady progress in deciphering the molecular basis of plant disease resistance and pathogen virulence. Although contributions have been made using many different plant and pathogen species, studies of the interactions between Arabidopsis thaliana and Pseudomonas syringae have yielded a particularly significant body of information. The present review focuses on recent findings regarding R gene products and the guard hypothesis, RAR1/SGT1 and other examples where protein processing activity is implicated in disease resistance or susceptibility, the use of microarray expression profiling to generate information and experimental leads, and important molecular- and genome-level discoveries regarding P. syringae effectors that mediate bacterial virulence. The development of the Arabidopsis-Pseudomonas model system is also reviewed briefly, and we close with a discussion of characteristics to consider when selecting other pathosystems as experimentally tractable models for future research.

  20. Deciphering the enigmatic face: the importance of facial dynamics in interpreting subtle facial expressions.

    PubMed

    Ambadar, Zara; Schooler, Jonathan W; Cohn, Jeffrey F

    2005-05-01

    Most studies investigating the recognition of facial expressions have focused on static displays of intense expressions. Consequently, researchers may have underestimated the importance of motion in deciphering the subtle expressions that permeate real-life situations. In two experiments, we examined the effect of motion on perception of subtle facial expressions and tested the hypotheses that motion improves affect judgment by (a) providing denser sampling of expressions, (b) providing dynamic information, (c) facilitating configural processing, and (d) enhancing the perception of change. Participants viewed faces depicting subtle facial expressions in four modes (single-static, multi-static, dynamic, and first-last). Experiment 1 demonstrated a robust effect of motion and suggested that this effect was due to the dynamic property of the expression. Experiment 2 showed that the beneficial effect of motion may be due more specifically to its role in perception of change. Together, these experiments demonstrated the importance of motion in identifying subtle facial expressions.

  1. Comparative investigation of Au nano-particle formation process dependent upon various protective agents

    NASA Astrophysics Data System (ADS)

    Eitoku, Takeshi; Taniguchi, Kazuya; Nakazato, Yuta; Ono, Shunichi; Katayama, Kenji

    2010-01-01

    Formation process of gold nanoparticles was investigated by near-field heterodyne transient grating method. In the absence of the protective agents, although the diffusion of H[AuICl2] could be observed after the photo-reduction of H[AuIIICl4], the diffusion of nanoparticle-seeds was not observed. On the other hand, in the presence of the protective agents, the diffusion of a complex molecule (Au and protective agent) and nanoparticle-seeds could be observed. From these results, it was found that enough amount of the complex is essential for the nanoparticle formation. We also investigated the formation process with four different chemicals as a protective agent. The hydrodynamic radius of nanoparticle-seeds generated in the poly(vinyl pyrrolidone) and TritonX-100 solutions were larger than those generated in the Tween 20 and Brij 58 solutions. The former two have hydrophilic chain in the molecular structure; on the other hand, the latter two have hydrophobic alkyl chain. Based on those facts, we concluded that the interaction between the chains of the complex molecule plays an important role in the nanoparticle formation process.

  2. The Policy Formation Process: A Conceptual Framework for Analysis. Ph.D. Thesis

    NASA Technical Reports Server (NTRS)

    Fuchs, E. F.

    1972-01-01

    A conceptual framework for analysis which is intended to assist both the policy analyst and the policy researcher in their empirical investigations into policy phenomena is developed. It is meant to facilitate understanding of the policy formation process by focusing attention on the basic forces shaping the main features of policy formation as a dynamic social-political-organizational process. The primary contribution of the framework lies in its capability to suggest useful ways of looking at policy formation reality. It provides the analyst and the researcher with a group of indicators which suggest where to look and what to look for when attempting to analyze and understand the mix of forces which energize, maintain, and direct the operation of strategic level policy systems. The framework also highlights interconnections, linkage, and relational patterns between and among important variables. The framework offers an integrated set of conceptual tools which facilitate understanding of and research on the complex and dynamic set of variables which interact in any major strategic level policy formation process.

  3. Mechanism of hologram formation in fixation-free rehalogenating bleaching processes.

    PubMed

    Neipp, Cristian; Pascual, Inmaculada; Beléndez, Augusto

    2002-07-10

    The mechanism of hologram formation in fixation-free rehalogenating bleaching processes have been treated by different authors. The experiments carried out on Agfa 8E75 HD plates led to the conclusion that material transfer from the exposed to the unexposed zones is the main mechanism under theprocess. We present a simple model that explains the mechanism of hologram formation inside the emulsion. Also quantitative data obtained using both Agfa 8E75 HD and Slavich PFG-01 fine-grained red-sensitive emulsions are given and good agreement between theory and experiments are found.

  4. Study of the formation, prevention, and recovery of plutonium from plutonium esters in the Purex process

    SciTech Connect

    Gray, L. W.; Burney, G. A.

    1981-01-01

    The Savannah River Plant uses the basic Purex process to separate /sup 239/Pu from /sup 238/U and fission products. Dark-brown, dense solids containing up to 30% Pu have previously occurred in rotameters in the plutonium finishing operations. The kinetics of formation of this mixture of DBP- and MBP-Pu esters suggest two methods to prevent the formation of the solids. A selective dissolution method using NaOH metathesis has been developed to separate the phosphate ester from the plutonium before dissolution of the residual plutonium hydroxide in a HNO/sub 3/-HF medium.

  5. Essential processes for cognitive behavioral clinical supervision: Agenda setting, problem-solving, and formative feedback.

    PubMed

    Cummings, Jorden A; Ballantyne, Elena C; Scallion, Laura M

    2015-06-01

    Clinical supervision should be a proactive and considered endeavor, not a reactive one. To that end, supervisors should choose supervision processes that are driven by theory, best available research, and clinical experience. These processes should be aimed at helping trainees develop as clinicians. We highlight 3 supervision processes we believe should be used at each supervision meeting: agenda setting, encouraging trainee problem-solving, and formative feedback. Although these are primarily cognitive-behavioral skills, they can be helpful in combination with other supervision models. We provide example dialogue from supervision exchanges, and discuss theoretical and research support for these processes. Using these processes not only encourages trainee development but also models for them how to use the same processes and approaches with clients.

  6. Processes underlying developmental reversals in false-memory formation: comment on Brainerd, Reyna, and Ceci (2008).

    PubMed

    Ghetti, Simona

    2008-09-01

    C. J. Brainerd, V. F. Reyna, and S. J. Ceci (2008) reviewed compelling evidence of developmental reversals in false-memory formation (i.e., younger children exhibit lower false-memory rates than do older children and adults) and proposed that this phenomenon depends on the development of gist processing (i.e., the ability to identify and process the semantic theme of word lists, events, etc.). A full understanding of development reversals, however, cannot be achieved without further characterizing the role played by complementary or opposing processes. Suggestions for future research are made from this perspective.

  7. Formation of insoluble organic matter in type-1 and -2 chondrites: Radiolytic or thermal processes?

    NASA Astrophysics Data System (ADS)

    Quirico, E.; Orthous-Daunay, F.; Beck, P.; Bonal, L.; Brunetto, R.; Dartois, E.; Pino, T.; Montagnac, G.; Rouzaud, J.; Engrand, C.; Duprat, J.

    2014-07-01

    Insoluble organic matter (IOM) extracted from primitive chondrites comes in the form of a polyaromatic solid with a structure and composition resembling that of terrestrial kerogens. It bears large D/H and ^{15}N/^{14}N isotopic ratios that point to a formation in a cold environment and ion-molecule reactions. However, the nature of the chemical and physical processes that led to its formation is still actively discussed: formation in the parent body by slight thermal metamorphism [1], inheritance from interstellar medium [2], or formation in the upper layer of the protosolar disk [3]. Post-accretional evolution of organic matter has also emerged as a critical issue, as it may disturb or even obscure pre-accretional information. In type 1 and 2 chondrites, evidence of short duration thermal heating of OM has been found using a variety of techniques [4]. In order to unravel pre-accretional from post-accretional processes, we have performed a survey of the composition and structure of IOM on a series of 27 CR, CM, CI, and ungrouped C2 carbonaceous chondrites (Tagish Lake, Bells, Essebi, Acfer 094) using infrared and multi-wavelength Raman micro-spectroscopy (244-, 514-, and 785-nm laser excitations [5]). Our results show that chondritic IOM from PCA 91008 (CM2), WIS 91600 (CM2), QUE 93005 (CM2), Tagish Lake (C2 ungrouped), and possibly Cold Bokkeveld (CM2) has been subjected to the past action of short-duration thermal metamorphism, presumably triggered by impacts. The IOM in most of the CM chondrites that experienced moderate to heavy aqueous alteration may have been slightly modified by collision-induced heating. Even IOM from chondrites that escaped significant thermal metamorphism (e.g., the most primitive CR chondrites) displays Raman characteristics consistent with a formation by thermal processing. This process may have happened either in the protosolar disk or in the parent body. However, an alternative energetic process to thermal heating is ion irradiation

  8. Formation of nitroaromatic compounds in advanced oxidation processes: Photolysis versus photocatalysis

    SciTech Connect

    Dzengel, J.; Theurich, J.; Bahnemann, D.W.

    1999-01-15

    There is a growing demand for efficient treatment of organic polluted wastewaters by advanced oxidation processes (AOPs). Besides optimization of the processes, the detailed understanding of degradation mechanisms and interactions of organic pollutants with inorganic substrates is important for technical applications of AOPs. Therefore, the aim of the present study was to investigate the influence of nitrate ions on the photooxidation of phenol for various AOPs at different pH values. Three different oxidation processes were compared in these studies: direct photolysis, TiO{sub 2}/UV, and H{sub 2}O{sub 2}/UV. Special emphasis has been laid on the analysis of byproducts especially on the formation of nitroaromatic compounds. The formation of intermediates as well as the depletion of phenol were monitored by HPLC technique. The total organic carbon content, TOC, was measured to monitor the mineralization. Highest degradation rates and lowest concentrations of intermediates were observed with TiO{sub 2}/UV being the AOP. Formation of highly toxic nitrophenols was only observed when homogeneous AOPs were employed. For the TiO{sub 2}/UV process no formation of Nitroaromatic byproducts occurred. At pH 5 formation of nitrophenols was observed employing direct photolysis in the presence of NO{sub 2}{sup {minus}}, while with H{sub 2}O{sub 2}/UV nitrophenols were detected only when the concentration of NO{sub 2}{sup {minus}} was higher than that of H{sub 2}O{sub 2}. At pH 11 no nitroaromatic intermediates were found for any AOPs compared in this study.

  9. Statistical Behavior of Formation Process of Magnetic Vortex State in Ni80Fe20 Nanodisks

    SciTech Connect

    Im, Mi-Young; Fischer, Peter; Keisuke, Yamada; Kasai, Shinya

    2011-01-14

    Magnetic vortices in magnetic nanodots, which are characterized by an in-plane (chirality) and an out-of-plane (polarity) magnetizations, have been intensively attracted because of their high potential for technological application to data storage and memory scheme as well as their scientific interest for an understanding of fundamental physics in magnetic nanostructures. Complete understanding of the formation process of vortex state in magnetic vortex systems is very significant issue to achieve storage and memory technologies using magnetic vortices and understand intrinsic physical properties in magnetic nanostructures. In our work, we have statistically investigated the formation process of vortex state in permalloy (Py, Ni{sub 80}Fe{sub 20}) nanodisks through the direct observation of vortex structure utilizing a magnetic transmission soft X-ray microscopy (MTXM) with a high spatial resolution down to 20 nm. Magnetic imaging in Py nanodots was performed at the Fe L{sub 3} (707 eV) absorption edge. Figure 1 shows in-plane and out-of-plane magnetic components observed in 40 nm thick nanodot arrays with different dot radius of r = 500 and 400 nm, respectively. Vortex chirality, either clockwise (CW) or counter-clockwise (CCW), and polarity, either up or down, are clearly visible in both arrays. To investigate the statistical behavior in formation process of the vortex state, the observation of vortex structure at a remanant state after saturation of nanodots by an external magnetic field of 1 kOe has been repeatedly performed over 100 times for each array. The typical MTXM images of vortex chirality taken in two successive measurements together with their overlapped images in nanodot arrays of r = 500 and 400 nm are displayed in Fig. 2. Within the statistical measurement, the formation process of chirality of either CW or CCW is quite stochastic in each nanodot. Similar behavior is also witnessed in the formation of vortex polarity observed in consecutive

  10. Deciphering the acute cellular phosphoproteome response to irradiation with X-rays, protons and carbon ions.

    PubMed

    Winter, Martin; Dokic, Ivana; Schlegel, Julian; Warnken, Uwe; Debus, Jürgen; Abdollahi, Amir; Schnölzer, Martina

    2017-03-16

    Radiotherapy is a cornerstone of cancer therapy. The recently established particle therapy with raster-scanning protons and carbon ions landmarks a new era in the field of high-precision cancer medicine. However, molecular mechanisms governing radiation induced intracellular signaling remain elusive. Here, we present the first comprehensive proteomic and phosphoproteomic study applying stable isotope labeling by amino acids in cell culture (SILAC) in combination with high-resolution mass spectrometry to decipher cellular response to irradiation with X-rays, protons and carbon ions. At protein expression level limited alterations were observed 2h post irradiation of human lung adenocarcinoma cells. In contrast, 181 phosphorylation sites were found to be differentially regulated out of which 151 sites were not hitherto attributed to radiation response as revealed by crosscheck with the PhosphoSitePlus database. Radiation-induced phosphorylation of the p(S/T)Q motif was the prevailing regulation pattern affecting proteins involved in DNA damage response signaling. Since radiation doses were selected to produce same level of cell kill and DNA double-strand breakage for each radiation quality, DNA damage responsive phosphorylation sites were regulated to same extent. However, differential phosphorylation between radiation qualities was observed for 55 phosphorylation sites indicating the existence of distinct signaling circuitries induced by X-ray versus particle (proton/carbon) irradiation beyond the canonical DNA damage response. This unexpected finding was confirmed in targeted spike-in experiments using synthetic isotope labeled phosphopeptides. Herewith, we successfully validated uniform DNA damage response signaling coexisting with altered signaling involved in apoptosis and metabolic processes induced by X-ray and particle based treatments. In summary, the comprehensive insight into the radiation-induced phosphoproteome landscape is instructive for the design of

  11. Deciphering Late-Pleistocence landscape evolution: linking proxies by combining pedo-stratigraphy and luminescence dating

    NASA Astrophysics Data System (ADS)

    Kreutzer, Sebastian; Meszner, Sascha; Faust, Dominik; Fuchs, Markus

    2014-05-01

    Interpreting former landscape evolution asks for understanding the processes that sculpt such landforms by means of deciphering complex systems. For reconstructing terrestrial Quaternary environments based on loess archives this might be considered, at least, as a three step process: (1) Identifying valuable records in appropriate morphological positions in a previously defined research area, (2) analysing the profiles by field work and laboratory methods and finally (3) linking the previously considered pseudo-isolated systems to set up a comprehensive picture. Especially the first and the last step might bring some pitfalls, as it is tempting to specify single records as pseudo-isolated, closed systems. They might be, with regard to their preservation in their specific morphological position, but in fact they are part of a complex, open system. Between 2008 and 2013, Late-Pleistocene loess archives in Saxony have been intensively investigated by field and laboratory methods. Linking pedo- and luminescence dating based chronostratigraphies, a composite profile for the entire Saxonian Loess Region has been established. With this, at least, two-fold approach we tried to avoid misinterpretations that might appear when focussing on one standard profile in an open morphological system. Our contribution focuses on this multi-proxy approach to decipher the Late-Pleistocene landscape evolution in the Saxonian Loess Region. Highlighting the challenges and advantages of combining different methods, we believe that (1) this multi-proxy approach is without alternative, (2) the combination of different profiles may simplify the more complex reality, but it may be a useful generalisation to understand and reveal the stratigraphical significance of the landscape evolution in this region.

  12. Have a break: determinants of meiotic DNA double strand break (DSB) formation and processing in plants.

    PubMed

    Edlinger, Bernd; Schlögelhofer, Peter

    2011-03-01

    Meiosis is an essential process for sexually reproducing organisms, leading to the formation of specialized generative cells. This review intends to highlight current knowledge of early events during meiosis derived from various model organisms, including plants. It will particularly focus on cis- and trans-requirements of meiotic DNA double strand break (DSB) formation, a hallmark event during meiosis and a prerequisite for recombination of genetic traits. Proteins involved in DSB formation in different organisms, emphasizing the known factors from plants, will be introduced and their functions outlined. Recent technical advances in DSB detection and meiotic recombination analysis will be reviewed, as these new tools now allow analysis of early meiotic recombination in plants with incredible accuracy. To anticipate future directions in plant meiosis research, unpublished results will be included wherever possible.

  13. Dynamics of Faceted Nanoparticles Formation in a Crystalline Matrix During Ion Implantation Processing.

    PubMed

    Li, Kun-Dar

    2016-02-01

    The faceted nanoparticle synthesized by ion implantation, such as Zn, Cu or Ag nanoparticles, is one of the promising materials for the next generation of optical devices. To understand and better control the manufacturing processes of ion implantation, a theoretical model is applied to investigate the formation and evolution of faceted nanoparticles under various experimental conditions of implantation processing. In this study, the mechanisms of the anisotropic interfacial energy and kinetics with different ion distributions are taken into consideration to demonstrate the role of the crystallographic symmetry, ion energy and temperature on the faceted nanoparticles formation in a crystalline matrix. As presented in the numerical results, the morphological shape of the nanoparticles is mainly affected by the crystallographic symmetry, while the distribution of the precipitates is principally determined by the ion energy. For the condition of high-temperature implantation, a high mobility of ions causes the characteristic length of nanostructures to increase and creates a coarsening morphology of nanoparticles. It is attributed to a longer diffusion distance during the nucleation and growth processes. This model can be widely used for the predictions of the nanostructures formation with various ion implantation processes.

  14. Elucidation of an Iterative Process of Carbon-Carbon Bond Formation of Prebiotic Significance

    NASA Astrophysics Data System (ADS)

    Loison, Aurélie; Dubant, Stéphane; Adam, Pierre; Albrecht, Pierre

    2010-12-01

    Laboratory experiments carried out under plausible prebiotic conditions (under conditions that might have occurred at primitive deep-sea hydrothermal vents) in water and involving constituents that occur in the vicinity of submarine hydrothermal vents (e.g., CO, H2S, NiS) have disclosed an iterative Ni-catalyzed pathway of C-C bond formation. This pathway leads from CO to various organic molecules that comprise, notably, thiols, alkylmono- and disulfides, carboxylic acids, and related thioesters containing up to four carbon atoms. Furthermore, similar experiments with organic compounds containing various functionalities, such as thiols, carboxylic acids, thioesters, and alcohols, gave clues to the mechanisms of this novel synthetic process in which reduced metal species, in particular Ni(0), appear to be the key catalysts. Moreover, the formation of aldehydes (and ketones) as labile intermediates via a hydroformylation-related process proved to be at the core of the chain elongation process. Since this process can potentially lead to organic compounds with any chain length, it could have played a significant role in the prebiotic formation of lipidic amphiphilic molecules such as fatty acids, potential precursors of membrane constituents.

  15. Formation of iron nanoparticles and increase in iron reactivity in mineral dust during simulated cloud processing.

    PubMed

    Shi, Zongbo; Krom, Michael D; Bonneville, Steeve; Baker, Alex R; Jickells, Timothy D; Benning, Liane G

    2009-09-01

    The formation of iron (Fe) nanoperticles and increase in Fe reactivity in mineral dust during simulated cloud processing was investigated using high-resolution microscopy and chemical extraction methods. Cloud processing of dust was experimentally simulated via an alternation of acidic (pH 2) and circumneutral conditions (pH 5-6) over periods of 24 h each on presieved (<20 microm) Saharan soil and goethite suspensions. Microscopic analyses of the processed soil and goethite samples reveal the neo-formation of Fe-rich nanoparticle aggregates, which were not found initially. Similar Fe-rich nanoparticles were also observed in wet-deposited Saharen dusts from the western Mediterranean but not in dry-deposited dust from the eastern Mediterranean. Sequential Fe extraction of the soil samples indicated an increase in the proportion of chemically reactive Fe extractable by an ascorbate solution after simulated cloud processing. In addition, the sequential extractions on the Mediterranean dust samples revealed a higher content of reactive Fe in the wet-deposited dust compared to that of the dry-deposited dust These results suggestthat large variations of pH commonly reported in aerosol and cloud waters can trigger neo-formation of nanosize Fe particles and an increase in Fe reactivity in the dust

  16. Applications of all optical signal processing for advanced optical modulation formats

    NASA Astrophysics Data System (ADS)

    Nuccio, Scott R.

    signal processing may play a role in the future development of more efficient optical transmission systems. The hope is that performing signal processing in the optical domain may reduce optical-to-electronic conversion inefficiencies, eliminate bottlenecks and take advantage of the ultrahigh bandwidth inherent in optics. While 40 to 50 Gbit/s electronic components are the peak of commercial technology and 100 Gbit/s capable RF components are still in their infancy, optical signal processing of these high-speed data signals may provide a potential solution. Furthermore, any optical processing system or sub-system must be capable of handling the wide array of data formats and data rates that networks may employ. It is also worth noting that future networks may use a combination of data-rates and formats while it has been estimated that "we may start seeing the first commercial use of Terabit Ethernets by 2015". -Robert Metcalfe. To this end, the work presented in this Ph.D. dissertation is aimed at addressing the issue of optical processing for advanced optical modulation formats. All optical multiplexing and demultiplexing of Pol-MUX and phase and QAM encoded signals at the 100 Gbit/s Ethernet standard is addressed. The creation and development of an extremely large continuously tunable all-optical delay capable of handling a variety of modulation formats and data rates is presented. As optical delays are viewed as a critical element to achieve efficient and reconfigurable signal processing, the presented delay line is also utilized to enable a tunable packet buffer capable of handling data packets of varying rate, varying size, and multiple modulation formats.

  17. Motivational influences on impression formation: outcome dependency, accuracy-driven attention, and individuating processes.

    PubMed

    Neuberg, S L; Fiske, S T

    1987-09-01

    How might being outcome dependent on another person influence the processes that one uses to form impressions of that person? We designed three experiments to investigate this question with respect to short-term, task-oriented outcome dependency. In all three experiments, subjects expected to interact with a young man formerly hospitalized as a schizophrenic, and they received information about the person's attributes in either written profiles or videotapes. In Experiment 1, short-term, task-oriented outcome dependency led subjects to use relatively individuating processes (i.e., to base their impressions of the patient on his particular attributes), even under conditions that typically lead subjects to use relatively category-based processes (i.e., to base their impressions on the patient's schizophrenic label). Moreover, in the conditions that elicited individuating processes, subjects spent more time attending to the patient's particular attribute information. Experiment 2 demonstrated that the attention effects in Experiment 1 were not merely a function of impression positivity and that outcome dependency did not influence the impression formation process when attribute information in addition to category-level information was unavailable. Finally, Experiment 3 manipulated not outcome dependency but the attentional goal of forming an accurate impression. We found that accuracy-driven attention to attribute information also led to individuating processes. The results of the three experiments indicate that there are important influences of outcome dependency on impression formation. These results are consistent with a model in which the tendency for short-term, task-oriented outcome dependency to facilitate individuating impression formation processes is mediated by an increase in accuracy-driven attention to attribute information.

  18. Suppression of compensating native defect formation during semiconductor processing via excess carriers

    SciTech Connect

    Alberi, Kirstin; Scarpulla, M. A.

    2016-06-21

    In many semiconductors, compensating defects set doping limits, decrease carrier mobility, and reduce minority carrier lifetime thus limiting their utility in devices. Native defects are often responsible. Suppressing the concentrations of compensating defects during processing close to thermal equilibrium is difficult because formation enthalpies are lowered as the Fermi level moves towards the majority band edge. Excess carriers, introduced for example by photogeneration, modify the formation enthalpy of semiconductor defects and thus can be harnessed during crystal growth or annealing to suppress defect populations. Herein we develop a rigorous and general model for defect formation in the presence of steady-state excess carrier concentrations by combining the standard quasi-chemical formalism with a detailed-balance description that is applicable for any defect state in the bandgap. Considering the quasi-Fermi levels as chemical potentials, we demonstrate that increasing the minority carrier concentration increases the formation enthalpy for typical compensating centers, thus suppressing their formation. Furthermore, this effect is illustrated for the specific example of GaSb. While our treatment is generalized for excess carrier injection or generation in semiconductors by any means, we provide a set of guidelines for applying the concept in photoassisted physical vapor deposition.

  19. Suppression of compensating native defect formation during semiconductor processing via excess carriers

    DOE PAGES

    Alberi, Kirstin; Scarpulla, M. A.

    2016-06-21

    In many semiconductors, compensating defects set doping limits, decrease carrier mobility, and reduce minority carrier lifetime thus limiting their utility in devices. Native defects are often responsible. Suppressing the concentrations of compensating defects during processing close to thermal equilibrium is difficult because formation enthalpies are lowered as the Fermi level moves towards the majority band edge. Excess carriers, introduced for example by photogeneration, modify the formation enthalpy of semiconductor defects and thus can be harnessed during crystal growth or annealing to suppress defect populations. Herein we develop a rigorous and general model for defect formation in the presence of steady-statemore » excess carrier concentrations by combining the standard quasi-chemical formalism with a detailed-balance description that is applicable for any defect state in the bandgap. Considering the quasi-Fermi levels as chemical potentials, we demonstrate that increasing the minority carrier concentration increases the formation enthalpy for typical compensating centers, thus suppressing their formation. Furthermore, this effect is illustrated for the specific example of GaSb. While our treatment is generalized for excess carrier injection or generation in semiconductors by any means, we provide a set of guidelines for applying the concept in photoassisted physical vapor deposition.« less

  20. Suppression of compensating native defect formation during semiconductor processing via excess carriers

    PubMed Central

    Alberi, K.; Scarpulla, M. A.

    2016-01-01

    In many semiconductors, compensating defects set doping limits, decrease carrier mobility, and reduce minority carrier lifetime thus limiting their utility in devices. Native defects are often responsible. Suppressing the concentrations of compensating defects during processing close to thermal equilibrium is difficult because formation enthalpies are lowered as the Fermi level moves towards the majority band edge. Excess carriers, introduced for example by photogeneration, modify the formation enthalpy of semiconductor defects and thus can be harnessed during crystal growth or annealing to suppress defect populations. Herein we develop a rigorous and general model for defect formation in the presence of steady-state excess carrier concentrations by combining the standard quasi-chemical formalism with a detailed-balance description that is applicable for any defect state in the bandgap. Considering the quasi-Fermi levels as chemical potentials, we demonstrate that increasing the minority carrier concentration increases the formation enthalpy for typical compensating centers, thus suppressing their formation. This effect is illustrated for the specific example of GaSb. While our treatment is generalized for excess carrier injection or generation in semiconductors by any means, we provide a set of guidelines for applying the concept in photoassisted physical vapor deposition. PMID:27323863

  1. Suppression of compensating native defect formation during semiconductor processing via excess carriers

    NASA Astrophysics Data System (ADS)

    Alberi, K.; Scarpulla, M. A.

    2016-06-01

    In many semiconductors, compensating defects set doping limits, decrease carrier mobility, and reduce minority carrier lifetime thus limiting their utility in devices. Native defects are often responsible. Suppressing the concentrations of compensating defects during processing close to thermal equilibrium is difficult because formation enthalpies are lowered as the Fermi level moves towards the majority band edge. Excess carriers, introduced for example by photogeneration, modify the formation enthalpy of semiconductor defects and thus can be harnessed during crystal growth or annealing to suppress defect populations. Herein we develop a rigorous and general model for defect formation in the presence of steady-state excess carrier concentrations by combining the standard quasi-chemical formalism with a detailed-balance description that is applicable for any defect state in the bandgap. Considering the quasi-Fermi levels as chemical potentials, we demonstrate that increasing the minority carrier concentration increases the formation enthalpy for typical compensating centers, thus suppressing their formation. This effect is illustrated for the specific example of GaSb. While our treatment is generalized for excess carrier injection or generation in semiconductors by any means, we provide a set of guidelines for applying the concept in photoassisted physical vapor deposition.

  2. FTOOLS - A New Package of Programs to Manipulate and Process FITS Format Files

    NASA Astrophysics Data System (ADS)

    Pence, W. D.

    1992-05-01

    The High Energy Astrophysics Science Archive Research Center (HEASARC) is developing a comprehensive set of programs to manipulate and analyze files in FITS (Flexible Image Transport System) format. One consequence of this project is to greatly expand the usage of FITS from simply a transport or interchange format to a convenient and versatile format to be used directly for data reduction and analysis. The FTOOLS utilities are specifically being written to process the data from the Astro-D X-Ray satellite, but the tools themselves are very general and can be used to analyze any FITS format file. These utilities are built on top of the FITSIO subroutine library and are written in ANSI standard Fortran or C. The software is easily portable to different processing environments and will be available as an IRAF package as well as a set of stand-alone set of executable tasks on VMS or Unix systems. The current status of the FTOOLS project will be described along with plans for future enhancements.

  3. The indication of Martian gully formation processes by slope-area analysis

    USGS Publications Warehouse

    Conway, S.J.; Balme, M.R.; Murray, J.B.; Towner, M.C.; Okubo, C.H.; Grindrod, P.M.

    2011-01-01

    The formation process of recent gullies on Mars is currently under debate. This study aims to discriminate between the proposed formation processes - pure water flow, debris flow and dry mass wasting - through the application of geomorphological indices commonly used in terrestrial geomorphology. High-resolution digital elevation models (DEMs) of Earth and Mars were used to evaluate the drainage characteristics of small slope sections. Data from Earth were used to validate the hillslope, debris-flow and alluvial process domains previously found for large fluvial catchments on Earth, and these domains were applied to gullied and ungullied slopes on Mars. In accordance with other studies, our results indicate that debris flow is one of the main processes forming the Martian gullies that were being examined. The source of the water is predominantly distributed surface melting, not an underground aquifer. Evidence is also presented indicating that other processes may have shaped Martian crater slopes, such as ice-assisted creep and solifluction, in agreement with the proposed recent Martian glacial and periglacial climate. Our results suggest that, within impact craters, different processes are acting on differently oriented slopes, but further work is needed to investigate the potential link between these observations and changes in Martian climate. ?? The Geological Society of London 2011.

  4. Formation of Volatile Tea Constituent Indole During the Oolong Tea Manufacturing Process.

    PubMed

    Zeng, Lanting; Zhou, Ying; Gui, Jiadong; Fu, Xiumin; Mei, Xin; Zhen, Yunpeng; Ye, Tingxiang; Du, Bing; Dong, Fang; Watanabe, Naoharu; Yang, Ziyin

    2016-06-22

    Indole is a characteristic volatile constituent in oolong tea. Our previous study indicated that indole was mostly accumulated at the turn over stage of oolong tea manufacturing process. However, formation of indole in tea leaves remains unknown. In this study, one tryptophan synthase α-subunit (TSA) and three tryptophan synthase β-subunits (TSBs) from tea leaves were isolated, cloned, sequenced, and functionally characterized. Combination of CsTSA and CsTSB2 recombinant protein produced in Escherichia coli exhibited the ability of transformation from indole-3-glycerol phosphate to indole. CsTSB2 was highly expressed during the turn over process of oolong tea. Continuous mechanical damage, simulating the turn over process, significantly enhanced the expression level of CsTSB2 and amount of indole. These suggested that accumulation of indole in oolong tea was due to the activation of CsTSB2 by continuous wounding stress from the turn over process. Black teas contain much less indole, although wounding stress is also involved in the manufacturing process. Stable isotope labeling indicated that tea leaf cell disruption from the rolling process of black tea did not lead to the conversion of indole, but terminated the synthesis of indole. Our study provided evidence concerning formation of indole in tea leaves for the first time.

  5. Processes of Formation of Spheroidal Concretions and Inferences for "Blueberries" in Meridiani Planum Sediments

    NASA Technical Reports Server (NTRS)

    Coleman, Max

    2005-01-01

    The MER Opportunity Athena Science team has described spheroidal hematite nodules in sediments at Meridiani Planum on Mars [1]. They were informally referred to as "Blueberries" in the initial press releases and for brevity that is the name to be used in this abstract. Not all spheroidal objects in sediments are nodular concretions, but this paper will discuss the diagenetic processes possibly relevant to understanding the origin of the Blueberries. There are many occurrences of spheroidal diagenetic concretions in terrestrial sediments and detailed work has been done to understand the processes of their formation. In particular, it is possible to reconstruct the controls on their shapes and compositions, both mineral and chemical. Although there may not be good analogs for the Meridiani Planum hematite spherules on Earth, it may be possible to deduce the former environmental conditions that led to their formation and whether they might retain (or even be) biosignatures.

  6. Nanoparticle formation in the expansion process of a laser ablated plume

    NASA Astrophysics Data System (ADS)

    Takiya, T.; Umezu, I.; Yaga, M.; Han, M.

    2007-04-01

    In the present article, we describe the process of nanoparticle formation during pulsed laser ablation in an inert gas atmosphere. We investigated the interaction between laser ablated plumes and shock waves using one dimensional Eulerian fluid dynamics equations combined with a rate equation relating to a classical nucleation model of supersaturated vapors. The initial values for the plume immediately after laser irradiation onto a silicon target were calculated based on stochastic thermodynamics, which was first used by Houle et al. We found a certain case wherein the rate of nanoparticle formation becomes higher when a reflected shock wave passes through the plume. In that particular case, mono-dispersed nanoparticles can be generated by carrying out nucleation and nanoparticle growth as separate processes.

  7. V(D)J recombination coding junction formation without DNA homology: processing of coding termini.

    PubMed Central

    Boubnov, N V; Wills, Z P; Weaver, D T

    1993-01-01

    Coding junction formation in V(D)J recombination generates diversity in the antigen recognition structures of immunoglobulin and T-cell receptor molecules by combining processes of deletion of terminal coding sequences and addition of nucleotides prior to joining. We have examined the role of coding end DNA composition in junction formation with plasmid substrates containing defined homopolymers flanking the recombination signal sequence elements. We found that coding junctions formed efficiently with or without terminal DNA homology. The extent of junctional deletion was conserved independent of coding ends with increased, partial, or no DNA homology. Interestingly, G/C homopolymer coding ends showed reduced deletion regardless of DNA homology. Therefore, DNA homology cannot be the primary determinant that stabilizes coding end structures for processing and joining. PMID:8413286

  8. Process for establishing a clear horizontal borehole in a subterranean formation

    SciTech Connect

    Richards, W.L.; Henderson, R.L.; Aul, G.N.; Pauley, B.W.

    1987-09-08

    This patent describes a process for establishing a clear, generally horizontal borehole path in a subterranean formation having sloughing or caving characteristics. The process comprises the steps of: drilling a generally horizontal borehole into a subterranean formation having sloughing or caving characteristics using a drill bit and drill pipe; lubricating the drill bit and drill pipe with a mud capable of forming a cake on the borehole walls; withdrawing the drill bit and drill pipe and replacing the drill bit with a casing shoe. The cake maintains the borehole wall integrity while the drill pipe is removed from the borehole; inserting the casing shoe and drill pipe into the borehole; simultaneously inserting a liner into the generally horizontal borehole inside of the drill pipe; and removing the drill pipe and casing shoe while holding the liner within the borehole, the casing shoe passing on the outside of the liner as it is removed, the liner providing a clean path through the borehole.

  9. Robust carrier formation process in low-band gap organic photovoltaics

    NASA Astrophysics Data System (ADS)

    Yonezawa, Kouhei; Kamioka, Hayato; Yasuda, Takeshi; Han, Liyuan; Moritomo, Yutaka

    2013-10-01

    By means of femto-second time-resolved spectroscopy, we investigated the carrier formation process against film morphology and temperature (T) in highly-efficient organic photovoltaic, poly[[4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b '] dithiophene-2,6-diyl][3-fluoro-2-[(2-ethylhexyl)carbonyl]thieno[3,4-b] thiophenediyl

  10. Verbalization and imagery in the process of formation of operator labor skills

    NASA Technical Reports Server (NTRS)

    Mistyuk, V. V.

    1975-01-01

    Sensorimotor control tests show that mastering operational skills occurs under conditions that stimulate the operator to independent active analysis and summarization of current information with the goal of clarifying the signs and the integral images that are a model of the situation. Goal directed determination of such an image requires inner and external speech, activates and improves the thinking of the operator, accelerates the training process, increases its effectiveness, and enables the formation of strategies in anticipating the course of events.

  11. Langevin Dynamics Deciphers the Motility Pattern of Swimming Parasites

    NASA Astrophysics Data System (ADS)

    Zaburdaev, Vasily; Uppaluri, Sravanti; Pfohl, Thomas; Engstler, Markus; Friedrich, Rudolf; Stark, Holger

    2011-05-01

    The parasite African trypanosome swims in the bloodstream of mammals and causes the highly dangerous human sleeping sickness. Cell motility is essential for the parasite’s survival within the mammalian host. We present an analysis of the random-walk pattern of a swimming trypanosome. From experimental time-autocorrelation functions for the direction of motion we identify two relaxation times that differ by an order of magnitude. They originate from the rapid deformations of the cell body and a slower rotational diffusion of the average swimming direction. Velocity fluctuations are athermal and increase for faster cells whose trajectories are also straighter. We demonstrate that such a complex dynamics is captured by two decoupled Langevin equations that decipher the complex trajectory pattern by referring it to the microscopic details of cell behavior.

  12. Self-consistent modeling of jet formation process in the nanosecond laser pulse regime

    NASA Astrophysics Data System (ADS)

    Mézel, C.; Hallo, L.; Souquet, A.; Breil, J.; Hébert, D.; Guillemot, F.

    2009-12-01

    Laser induced forward transfer (LIFT) is a direct printing technique. Because of its high application potential, interest continues to increase. LIFT is routinely used in printing, spray generation and thermal-spike sputtering. Biological material such as cells and proteins have already been transferred successfully for the creation of biological microarrays. Recently, modeling has been used to explain parts of the ejection transfer process. No global modeling strategy is currently available. In this paper, a hydrodynamic code is utilized to model the jet formation process and estimate the constraints obeyed by the bioelements during the transfer. A self-consistent model that includes laser energy absorption, plasma formation via ablation, and hydrodynamic processes is proposed and confirmed with experimental results. Fundamental physical mechanisms via one-dimensional modeling are presented. Two-dimensional (2D) simplified solutions of the jet formation model equations are proposed. Predicted results of the model are jet existence and its velocity. The 2D simulation results are in good agreement with a simple model presented by a previous investigator.

  13. Effect of solvent type on the nanoparticle formation of atorvastatin calcium by the supercritical antisolvent process.

    PubMed

    Kim, Min-Soo; Song, Ha-Seung; Park, Hee Jun; Hwang, Sung-Joo

    2012-01-01

    The aims of this study were to identify how the solvent selection affects particle formation and to examine the effect of the initial drug solution concentration on mean particle size and particle size distribution in the supercritical antisolvent (SAS) process. Amorphous atorvastatin calcium was precipitated from seven different solvents using the SAS process. Particles with mean particle size ranging between 62.6 and 1493.7 nm were obtained by varying organic solvent type and solution concentration. By changing the solvent, we observed large variations in particle size and particle size distribution, accompanied by different particle morphologies. Particles obtained from acetone and tetrahydrofuran (THF) were compact and spherical fine particles, whereas those from N-methylpyrrolidone (NMP) and dimethylsulfoxide (DMSO) were agglomerated, with rough surfaces and relatively larger particle sizes. Interestingly, the mean particle size of atorvastatin calcium increased with an increase in the boiling point of the organic solvent used. Thus, for atorvastatin particle formation via the SAS process, particle size was determined mainly by evaporation of the organic solvent into the antisolvent phase. In addition, the mean particle size was increased with increasing drug solution concentration. In this study, from the aspects of particle size and solvent toxicity, acetone was the better organic solvent for controlling nanoparticle formation of atorvastatin calcium.

  14. Decipher correlation patterns post prostatectomy: initial experience from 2 342 prospective patients

    PubMed Central

    Den, R B; Santiago-Jimenez, M; Alter, J; Schliekelman, M; Wagner, J R; Renzulli II, J F; Lee, D I; Brito, C G; Monahan, K; Gburek, B; Kella, N; Vallabhan, G; Abdollah, F; Trabulsi, E J; Lallas, C D; Gomella, L G; Woodlief, T L; Haddad, Z; Lam, L L C; Deheshi, S; Wang, Q; Choeurng, V; du Plessis, M; Jordan, J; Parks, B; Shin, H; Buerki, C; Yousefi, K; Davicioni, E; Patel, V R; Shah, N L

    2016-01-01

    Background: Currently, there are multiple commercially available RNA-based biomarkers that are Medicare approved and suggested for use by the National Comprehensive Cancer Network guidelines. There is uncertainty as to which patients benefit from genomic testing and for whom these tests should be ordered. Here, we examined the correlation patterns of Decipher assay to understand the relationship between the Decipher and patient tumor characteristics. Methods: De-identified Decipher test results (including Decipher risk scores and clinicopathologic data) from 2 342 consecutive radical prostatectomy (RP) patients tested between January and September 2015 were analyzed. For clinical testing, tumor specimen from the highest Gleason grade was sampled using a 1.5 mm tissue punch. Decipher scores were calculated based on a previously locked model. Correlations between Decipher score and clinicopathologic variables were computed using Spearman's rank correlation. Mixed-effect linear models were used to study the association of practice type and Decipher score. The significance level was 0.05 for all tests. Results: Decipher score had a positive correlation with pathologic Gleason score (PGS; r=0.37, 95% confidence interval (CI) 0.34−0.41), pathologic T-stage (r=0.31, 95% CI 0.28−0.35), CAPRA-S (r=0.32, 95% CI 0.28−0.37) and patient age (r=0.09, 95% CI 0.05-0.13). Decipher reclassified 52%, 76% and 40% of patients in CAPRA-S low-, intermediate- and high-risk groups, respectively. We detected a 28% incidence of high-risk disease through the Decipher score in pT2 patients and 7% low risk in pT3b/pT4, PGS 8−10 patients. There was no significant difference in the Decipher score between patients from community centers and those from academic centers (P=0.82). Conclusions: Although Decipher correlated with baseline tumor characteristics for over 2 000 patients, there was significant reclassification of tumor aggressiveness as compared to clinical parameters alone

  15. Apparatus and process to enhance the uniform formation of hollow glass microspheres

    SciTech Connect

    Schumacher, Ray F

    2013-10-01

    A process and apparatus is provided for enhancing the formation of a uniform population of hollow glass microspheres. A burner head is used which directs incoming glass particles away from the cooler perimeter of the flame cone of the gas burner and distributes the glass particles in a uniform manner throughout the more evenly heated portions of the flame zone. As a result, as the glass particles are softened and expand by a released nucleating gas so as to form a hollow glass microsphere, the resulting hollow glass microspheres have a more uniform size and property distribution as a result of experiencing a more homogenous heat treatment process.

  16. Processing Impact on Monoclonal Antibody Drug Products: Protein Subvisible Particulate Formation Induced by Grinding Stress.

    PubMed

    Gikanga, Benson; Roshan-Eisner, Devon; Ovadia, Robert; Day, Eric S; Stauch, Oliver Boris; Maa, Yuh-Fun

    2016-10-27

    Subvisible particle formation in monoclonal antibody (mAb) drug product resulting from mixing and filling operations represents a significant processing risk that can lead to filter fouling and thereby lead to process delays or failures. Several previous studies from our lab and others demonstrated the formation of subvisible particulates in mAb formulations resulting from mixing operations using some bottom-mounted mixers or stirrer bars. It was hypothesized that the stress (e.g. shear/cavitation) derived from tight clearance and/or close contact between the impeller and shaft was responsible for SvP generation. These studies, however, could not distinguish between the two surfaces without contact (tight clearance) or between two contacting surfaces (close contact). In the present study we expand on those findings and utilize small scale mixing models that are able to, for the first time, distinguish between tight clearances and tight contact. In this study we evaluated different mixer types including a top-mounted mixer, several impeller-based bottom-mounted mixers and a rotary piston pump. The impact of tight clearance/close contact on subvisible particle formation in at-scale mixing platforms was demonstrated in the gap between the impeller and drive unit as well as between the piston and the housing of the pump. Furthermore, small-scale mixing models based on different designs of magnetic stir bars which mimic the tight clearance/close contact of the manufacturing-scale mixers also induced subvisible particles in mAb formulations. Additional small-scale models which feature tight clearance but no close contact (grinding) suggested that it is the repeated grinding/contacting of the moving parts and not the presence of tight clearance in the processing equipment that is the root cause of SvP formation. When multiple mAbs, Fabs (fragment antigen binding) or non-antibody related proteins were mixed in the small-scale mixing model, for molecules investigated, it

  17. The becoming: students' reflections on the process of professional identity formation in medical education.

    PubMed

    Sharpless, Joanna; Baldwin, Nell; Cook, Robert; Kofman, Aaron; Morley-Fletcher, Alessio; Slotkin, Rebecca; Wald, Hedy S

    2015-06-01

    Professional identity formation (PIF) within medical education is the multifaceted, individualized process through which students develop new ways of being in becoming physicians. Personal backgrounds, values, expectations, interests, goals, relationships, and role models can all influence PIF and may account for diversity of both experience and the active constructive process of professional formation. Guided reflection, including reflective writing, has been used to enhance awareness and meaning making within the PIF process for both students and medical educators and to shed light on what aspects of medical education are most constructive for healthy PIF. Student voices about the PIF process now emerging in the literature are often considered and interpreted by medical educators within qualitative studies or in broad theoretical overviews of PIF.In this Commentary, the authors present a chorus of individual student voices from along the medical education trajectory. Medical students (years 1-4) and a first-year resident in pediatrics respond to a variety of questions based on prevalent PIF themes extracted from the literature to reflect on their personal experiences of PIF. Topics queried included pretending in medical education, role of relationships, impact of formal and informal curricula on PIF (valuable aspects as well as suggestions for change), and navigating and developing interprofessional relationships and identities. This work aims to vividly illustrate the diverse and personal forces at play in individual students' PIF processes and to encourage future pedagogic efforts supporting healthy, integrated PIF in medical education.

  18. Formation of metal and dielectric liners using a solution process for deep trench capacitors.

    PubMed

    Ham, Yong-Hyun; Kim, Dong-Pyo; Baek, Kyu-Ha; Park, Kun-Sik; Kim, Moonkeun; Kwon, Kwang-Ho; Shin, Hong-Sik; Lee, Kijun; Do, Lee-Mi

    2012-07-01

    We demonstrated the feasibility of metal and dielectric liners using a solution process for deep trench capacitor application. The deep Si trench via with size of 10.3 microm and depth of 71 microm were fabricated by Bosch process in deep reactive ion etch (DRIE) system. The aspect ratio was about 7. Then, nano-Ag ink and poly(4-vinylphenol) (PVPh) were used to form metal and dielectric liners, respectively. The thicknesses of the Ag and PVPh liners were about 144 and 830 nm, respectively. When the curing temperature of Ag film increased from 120 to 150 degrees C, the sheet resistance decreased rapidly from 2.47 to 0.72 Omega/sq and then slightly decreased to 0.6 Omega/sq with further increasing the curing temperature beyond 150 degrees C. The proposed liner formation method using solution process is a simple and cost effective process for the high capacity of deep trench capacitor.

  19. Tectonic and Aqueous Processes in the Formation of Mass-wasting Features on Mars and Earth

    NASA Astrophysics Data System (ADS)

    Watkins, Jessica

    2015-10-01

    Fundamental to the advancement of planetary geology is an understanding of the interaction between tectonic and aqueous processes on planetary surfaces. This dissertation examines this interaction within two geomorphologic processes: landslide emplacement, on Mars and on Earth, and the formation of seasonal slope features on Mars. Long-runout landsliding in equatorial Valles Marineris, Mars is among the most prominent geomorphic occurrences shaping the canyon. However, the mechanism of landslide long-distance transport, and the highly debated role of water therein, remains elusive. Through systematic mapping of high-resolution satellite images, integrated with spectral analysis, we show that hydrated silicates played a decisive role in facilitating landslide transport by lubricating the basal sliding zone. This conclusion implies that clay minerals, generated by ancient water-rock interactions, exert a long-lasting influence on Mars surface processes. The Eureka Valley (EV) landslide is an unexamined, well-preserved long-runout landslide in arid southeast Eureka Valley, California. The field, photogeologic, spectral, and luminescence dating investigation presented here support initiation as a result of fault-generated fracture during the mid to early Holocene at minimum, and transport lubricated by the presence of basal clays, characterized by 3-D internal deformation, as the most likely EV landslide emplacement mechanism. This geomorphological characterization may be applied to long-runout landslides on Earth and other planetary surfaces, suggesting that their emplacement likely does not require the participation of water. Recurring slope lineae (RSL) are seasonal, narrow, low-albedo features extending down steep, equator-facing Mars slopes. RSL formation has been largely attributed to the seepage of near-surface water, though its source is not well understood. Through detailed analysis of high-resolution satellite images of RSL geologic contexts, we quantify the

  20. Cloud processing of organic compounds: Secondary organic aerosol and nitrosamine formation

    NASA Astrophysics Data System (ADS)

    Hutchings, James W., III

    Cloud processing of atmospheric organic compounds has been investigated through field studies, laboratory experiments, and numerical modeling. Observational cloud chemistry studies were performed in northern Arizona and fog studies in central Pennsylvania. At both locations, the cloud and fogs showed low acidity due to neutralization by soil dust components (Arizona) and ammonia (Pennsylvania). The field observations showed substantial concentrations (20-5500 ng•L -1) of volatile organic compounds (VOC) in the cloud droplets. The potential generation of secondary organic aerosol mass through the processing of these anthropogenic VOCs was investigated through laboratory and modeling studies. Under simulated atmospheric conditions, in idealized solutions, benzene, toluene, ethylbenzene, and xylene (BTEX) degraded quickly in the aqueous phase with half lives of approximately three hours. The degradation process yielded less volatile products which would contribute to new aerosol mass upon cloud evaporation. However, when realistic cloud solutions containing natural organic matter were used in the experiments, the reaction kinetics decreased with increasing organic carbon content, resulting in half lives of approximately 7 hours. The secondary organic aerosol (SUA) mass formation potential of cloud processing of BTEX was evaluated. SOA mass formation by cloud processing of BTEX, while strongly dependent on the atmospheric conditions, could contribute up to 9% of the ambient atmospheric aerosol mass, although typically ˜1% appears realistic. Field observations also showed the occurrence of N-nitrosodimethylamine (NDMA), a potent carcinogen, in fogs and clouds (100-340 ng•L -1). Laboratory studies were conducted to investigate the formation of NDMA from nitrous acid and dimethylamine in the homogeneous aqueous phase within cloud droplets. While NDMA was produced in the cloud droplets, the low yields (<1%) observed could not explain observational concentrations

  1. The role of thermal and mechanical processes in the formation of the Ross Sea summer polynya

    NASA Astrophysics Data System (ADS)

    Reddy, Tasha E.; Arrigo, Kevin R.; Holland, David M.

    2007-07-01

    Three decades of satellite observations collected during spring and early summer have shown a recurring region of ice-free water forming in the sea-ice cover of the Ross Sea, Antarctica. This Ross Sea summer polynya plays an important role in heat exchange between the ocean and atmosphere, ventilation of deep water, and is characterized by high biological productivity. Despite its appearance each year, the relative importance of different physical processes to its formation and maintenance are not widely agreed upon. Here we use a three-dimensional coupled ice/ocean model to better understand processes controlling the dynamics of the Ross Sea polynya. Results from the model control run agree favorably with satellite microwave imagery of sea ice. Model sensitivity studies suggest that polynya dynamics are insensitive to the amount of snowfall, the presence of the Ross Ice Shelf cavity, tides, and solar radiation penetrating the ice. The model results also corroborate earlier findings that both the advection of sea ice and heat entrainment from warm Modified Circumpolar Deep Water play a role in Ross Sea polynya development. More importantly, the model further demonstrates that advection of sea ice due to wind stress plays the primary role in summer polynya formation. Additionally, we suggest that (1) heat entrainment reduces the rate of sea ice formation rather than melts existing sea ice, and (2) advection of sea ice due to synoptic wind events associated with variations in atmospheric pressure are the processes primarily responsible for the formation and expansion of the Ross Sea summer polynya.

  2. Modifying the processing and handling of frozen broccoli for increased sulforaphane formation.

    PubMed

    Dosz, Edward B; Jeffery, Elizabeth H

    2013-09-01

    Frozen broccoli can provide a cheaper product, with a longer shelf life and less preparation time than fresh broccoli. We previously showed that several commercially available frozen broccoli products do not retain the ability to generate the cancer-preventative agent sulforaphane. We hypothesized that this was because the necessary hydrolyzing enzyme myrosinase was destroyed during blanching, as part of the processing that frozen broccoli undergoes. This study was carried out to determine a way to overcome loss of hydrolyzing activity. Industrial blanching usually aims to inactivate peroxidase, although lipoxygenase plays a greater role in product degradation during frozen storage of broccoli. Blanching at 86 °C or higher inactivated peroxidase, lipoxygenase, and myrosinase. Blanching at 76 °C inactivated 92% of lipoxygenase activity, whereas there was only an 18% loss in myrosinase-dependent sulforaphane formation. We considered that thawing frozen broccoli might disrupt membrane integrity, allowing myrosinase and glucoraphanin to come into contact. Thawing frozen broccoli for 9 h did not support sulforaphane formation unless an exogenous source of myrosinase was added. Thermal stability studies showed that broccoli root, as a source of myrosinase, was not more heat stable than broccoli floret. Daikon radish root supported some sulforaphane formation even when heated at 125 °C for 10 min, a time and temperature comparable to or greater than microwave cooking. Daikon radish (0.25%) added to frozen broccoli that was then allowed to thaw supported sulforaphane formation without any visual alteration to that of untreated broccoli.

  3. Influence of process parameters on phosphorus recovery by struvite formation from urine.

    PubMed

    Liu, Xiaoning; Hu, Zhengyi; Zhu, Chunyou; Wen, Guoqi; Meng, Xianchao; Lu, Jia

    2013-01-01

    Batch experiments were conducted to examine the influence of various process parameters on phosphorus (P) recovery by struvite formation from urine. The results showed that the Mg/P molar ratio is one of the most important parameters affecting P recovery. The Mg/P molar ratio of 1.3 was found the most reasonable for struvite formation, and the P removal efficiency reached more than 96.6%. An increase in pH of urine solutions from 8.7 to 10.0 did not significantly affect P removal, but the quality of crystal formed at pH 10.0 was poor based on scanning electron microscopy analysis. A longer mixing time positively affected struvite formation, and compared to without mixing, the P removal efficiency increased from 72.7 to 97.3% after 5 min of mixing. The addition of seed material had no influence on the P removal efficiency, but contributed to the formation of struvite clusters.

  4. Percolation blockage: A process that enables melt pond formation on first year Arctic sea ice

    NASA Astrophysics Data System (ADS)

    Polashenski, Chris; Golden, Kenneth M.; Perovich, Donald K.; Skyllingstad, Eric; Arnsten, Alexandra; Stwertka, Carolyn; Wright, Nicholas

    2017-01-01

    Melt pond formation atop Arctic sea ice is a primary control of shortwave energy balance in the Arctic Ocean. During late spring and summer, the ponds determine sea ice albedo and how much solar radiation is transmitted into the upper ocean through the sea ice. The initial formation of ponds requires that melt water be retained above sea level on the ice surface. Both theory and observations, however, show that first year sea ice is so highly porous prior to the formation of melt ponds that multiday retention of water above hydraulic equilibrium should not be possible. Here we present results of percolation experiments that identify and directly demonstrate a mechanism allowing melt pond formation. The infiltration of fresh water into the pore structure of sea ice is responsible for blocking percolation pathways with ice, sealing the ice against water percolation, and allowing water to pool above sea level. We demonstrate that this mechanism is dependent on fresh water availability, known to be predominantly from snowmelt, and ice temperature at melt onset. We argue that the blockage process has the potential to exert significant control over interannual variability in ice albedo. Finally, we suggest that incorporating the mechanism into models would enhance their physical realism. Full treatment would be complex. We provide a simple temperature threshold-based scheme that may be used to incorporate percolation blockage behavior into existing model frameworks.

  5. [In situ Raman spectroscopic observation of micro-processes of methane hydrate formation and dissociation].

    PubMed

    Liu, Chang-Ling; Ye, Yu-Guang; Meng, Qing-Guo; Lü, Wan-Jun; Wang, Fei-Fei

    2011-06-01

    Micro laser Raman spectroscopic technique was used for in situ observation of the micro-processes of methane hydrate formed and decomposed in a high pressure transparent capillary. The changes in clathrate structure of methane hydrate were investigated during these processes. The results show that, during hydrate formation, the Raman peak (2 917 cm(-1)) of methane gas gradually splits into two peaks (2 905 and 2 915 cm(-1)) representing large and small cages, respectively, suggesting that the dissolved methane molecules go into two different chemical environments. In the meantime, the hydrogen bonds interaction is strengthened because water is changing from liquid to solid state gradually. As a result, the O-H stretching vibrations of water shift to lower wavenumber. During the decomposition process of methane hydrates, the Raman peaks of the methane molecules both in the large and small cages gradually clear up, and finally turn into a single peak of methane gas. The experimental results show that laser Raman spectroscopy can accurately demonstrate some relevant information of hydrate crystal structure changes during the formation and dissociation processes of methane hydrate.

  6. First observation on the feasibility of scratch formation by pad-particle mixture in CMP process

    NASA Astrophysics Data System (ADS)

    Sung, In-Ha; Kim, Hong Jin; Yeo, Chang Dong

    2012-08-01

    Micro-scratch formation on a post-chemical mechanical polishing (CMP) wafer surface is one of the critical problems that should be solved for miniaturization and reliability of a semiconductor device. In this study, the mechanism of micro-scratch formation during CMP was investigated through experiments and simulations. When a used pad was utilized in the experiments, it was found that micro-scratches could be generated by the polishing process that was done with DI water and additive only without abrasive particles. In order to analyze these micro-scratches under a used pad process, the change in surface properties of the polishing pad before and after the CMP was investigated using various surface sensitive techniques. In addition, 2-dimensional finite element analysis (FEA) of CMP process was performed to verify the experimental results. Especially, the FE model with a particle put inside a pad pore was considered to examine how it plays a role in micro-scratch generation. In summary, the scientific results from experiments and simulations in this study first revealed that the pad-particle mixture could be formed on the pad surface during CMP process, which would be one of the major factors leading to micro-scratch generation.

  7. A case study on the formation and sharing process of science classroom norms

    NASA Astrophysics Data System (ADS)

    Chang, Jina; Song, Jinwoong

    2016-03-01

    The teaching and learning of science in school are influenced by various factors, including both individual factors, such as member beliefs, and social factors, such as the power structure of the class. To understand this complex context affected by various factors in schools, we investigated the formation and sharing process of science classroom norms in connection with these factors. By examining the developmental process of science classroom norms, we identified how the norms were realized, shared, and internalized among the members. We collected data through classroom observations and interviews focusing on two elementary science classrooms in Korea. From these data, factors influencing norm formation were extracted and developed as stories about norm establishment. The results indicate that every science classroom norm was established, shared, and internalized differently according to the values ingrained in the norms, the agent of norm formation, and the members' understanding about the norm itself. The desirable norms originating from values in science education, such as having an inquiring mind, were not established spontaneously by students, but were instead established through well-organized norm networks to encourage concrete practice. Educational implications were discussed in terms of the practice of school science inquiry, cultural studies, and value-oriented education.

  8. Formation processes of nanometer sized particles in low pressure Ar/CH{sub 4} rf plasmas

    SciTech Connect

    Beckers, J.; Vacaresse, G. D. G. J.; Stoffels, W. W.

    2008-09-07

    In this paper, formation and growth processes of nanometer and micrometer sized dust particles in low pressure Ar/CH{sub 4} rf (13.56 MHz) plasmas are investigated as function of temperature in the range 25-100 deg. C. During experiments the pressure was typically 0.8 mbar and the forward power to the plasma was {approx}70 Watt. Measuring the fundamental voltage, current and phase angle together with their harmonics (up to the fourth) gives a good method to monitor the creation and growth of these dust particles in time. Furthermore, laser light scattering measurements are performed to give information about the dust particle density. It has been shown that dust particle formation in these conditions depends greatly on temperature.

  9. SOA Formation from Aqueous Processing of BVOCs in the Southeastern United States during SOAS

    NASA Astrophysics Data System (ADS)

    Skog, K.; Keutsch, F. N.

    2013-12-01

    Secondary organic aerosol (SOA) contributes to climate change and adversely affects human health, but the formation of SOA is poorly understood. Recent studies have shown that aqueous processing of water soluble compounds like glyoxal and glycolaldehyde can help close the gap in our understanding of SOA formation. During June and July of 2013, a comprehensive suite of instruments were deployed at the Southern Oxidant and Aerosol Study (SOAS) Centreville, AL ground site measuring oxidants, glyoxal and glycolaldehyde as well as their precursors, anthropogenic influence, aerosol properties and meteorology. Results from a zero-dimensional gas phase photochemical model and a zero-dimensional aqueous SOA model will be compared to the observations. Analysis will focus on the modeled contribution of glyoxal and glycolaldehyde in the context of closing the aqueous SOA budget.

  10. A novel process for methanol synthesis. [Concurrent sythesis of methly formate and methanol

    SciTech Connect

    Tierney, J.W.; Wender, I.

    1992-01-01

    A bench-scale reactor is being used to conduct studies of the conversion of synthesis gas to methanol (MeOH) by a novel process. In previous reports, we provided evidence for a two-step reaction in series, the carbonylation reaction taking place mainly in a non-equilibrium region in the vicinity of the copper chromite surface, and the hydrogenolysis reaction taking place on the surface of the copper chromite. Interaction between the two catalysts enhances the rate of methanol formation. In this quarter, we investigated the effect of pore diffusion on reaction rate and obtained an expression for the rate of reaction for the methanol/methyl formate concurrent synthesis.

  11. A coherent light scanner for optical processing of large format transparencies

    NASA Technical Reports Server (NTRS)

    Callen, W. R.; Weaver, J. E.; Shackelford, R. G.; Walsh, J. R.

    1975-01-01

    A laser scanner is discussed in which the scanning beam is random-access addressable and perpendicular to the image input plane and the irradiance of the scanned beam is controlled so that a constant average irradiance is maintained after passage through the image plane. The scanner's optical system and design are described, and its performance is evaluated. It is noted that with this scanner, data in the form of large-format transparencies can be processed without the expense, space, maintenance, and precautions attendant to the operation of a high-power laser with large-aperture collimating optics. It is shown that the scanned format as well as the diameter of the scanning beam may be increased by simple design modifications and that higher scan rates can be achieved at the expense of resolution by employing acousto-optic deflectors with different relay optics.

  12. Platinum Partitioning at Low Oxygen Fugacity: Implications for Core Formation Processes

    NASA Technical Reports Server (NTRS)

    Medard, E.; Martin, A. M.; Righter, K.; Lanziroti, A.; Newville, M.

    2016-01-01

    Highly siderophile elements (HSE = Au, Re, and the Pt-group elements) are tracers of silicate / metal interactions during planetary processes. Since most core-formation models involve some state of equilibrium between liquid silicate and liquid metal, understanding the partioning of highly siderophile elements (HSE) between silicate and metallic melts is a key issue for models of core / mantle equilibria and for core formation scenarios. However, partitioning models for HSE are still inaccurate due to the lack of sufficient experimental constraints to describe the variations of partitioning with key variable like temperature, pressure, and oxygen fugacity. In this abstract, we describe a self-consistent set of experiments aimed at determining the valence of platinum, one of the HSE, in silicate melts. This is a key information required to parameterize the evolution of platinum partitioning with oxygen fugacity.

  13. Combustion and structure formation in SHS processes under microgravity conditions: SHS plans for microgravity experiments

    NASA Technical Reports Server (NTRS)

    Merzhanov, A. G.

    1995-01-01

    This paper outlines ISMAN suggestions for the joint NASA-RSA project 'Combustion and Structure formation in SHS Processes under Microgravity Conditions'. The basic ideas of this work naturally follow from our almost 30-year experience in the field of SHS. As a matter of fact, we have already obtained some results in the following two directions closely related to the microgravity problem. One is the studies on SHS processes in the field of centrifugal forces. These studies aimed at the intensification of gravity-sensitive SHS processes in multicomponent highly caloric systems forming melts at high overloads (up to 2000 g). In other words, these studies had the objectives that are inverse to those in the microgravity studies. The second group of results directly relates to the microgravity problem and the project under consideration. These experiments played the important role in establishing links between SHS and microgravity.

  14. A Multi-Wavelength Investigation of the Star Formation Processes in the SHIELD Galaxies

    NASA Astrophysics Data System (ADS)

    Teich, Yaron G.; McNichols, Andrew Thomas; Cannon, John M.

    2015-08-01

    We analyze the relationships between HI mass surface density and star formation in the 12 galaxies that comprise the Survey of HI in Extremely Low-Mass Dwarfs (SHIELD). The SHIELD galaxies were selected from the first ~10% of data from the Arecibo Legacy Fast ALFA (ALFALFA) survey; they harbor low-mass HI reservoirs (6.6 < log(M(HI)) < 7.8) that make them critical testbeds for our understanding of the process of star formation in shallow potential wells. Using HI imaging from the VLA, Hα imaging from the WIYN 3.5m telescope, and archival GALEX imaging (available for most sample members), we compare the locations and intensities of star formation with the properties of the neutral ISM. Despite the low HI column densities observed in these systems, each SHIELD galaxy has a significant blue stellar population; there is ongoing star formation in all but one of the galaxies. We find that the regions of Hα emission are co-located with regions of high HI column densities. We compare the degree of overlap of HI dense knots with local UV maxima, with the goal of identifying whether Hα or UV emission more strongly correlates with regions of high HI column density. We calculate the specific SFR and SFR density for the galaxies in the sample, and examine the relationships of HI mass and SFR (from Hα, UV, and averaged from both) for selected sources. We also calculate the star formation efficiency (SFE) for each galaxy in the sample (total SFR / total gas mass) and note its dependence on HI column density.This work is a result of collaboration with the SHIELD Team and is supported by NSF grant 1211683.

  15. Evaluation of trihalomethane formation potential in function of oxidation processes used during the drinking water production process.

    PubMed

    Mosteo, R; Miguel, N; Martin-Muniesa, S; Ormad, Maria P; Ovelleiro, José L

    2009-12-30

    The presence of natural organic matter (NOM) in both surface and groundwater supplies produces toxic by-products, mainly trihalomethanes (THMs), during oxidation steps in drinking water production. This research work shows the efficiency of different advanced oxidation processes (AOPs) based on ozone for the degradation of precursors of trihalomethanes in aqueous solutions. Completed treatments comprised different preoxidation processes (chlorination and AOP: O(3), O(3)/H(2)O(2), O(3)/TiO(2) and O(3)/H(2)O(2)/TiO(2)), adsorption with PAC (optional operation), coagulation-flocculation and final postchlorination applied to synthetic samples which were prepared by dilution of the soluble fraction of a humic solution. A direct chlorination of synthetic humic samples which display dissolved organic carbon close to 3 mg l(-1) produced a THM concentration of around 1600 microg CCl(3)l(-1) (measured as THMFP). Comparisons between the trihalomethane formation potential of initial synthetic samples and samples treated by prechlorination and coagulation-flocculation-decantation show that the main factor responsible for THM reduction is the coagulation-flocculation process since a decrease of 90% is achieved. Considering the various completed treatments studied, the most recommendable include preoxidation by ozonation, adsorption by PAC, coagulation-flocculation using aluminium sulphate followed by decantation and final postchlorination.

  16. Acrylamide: inhibition of formation in processed food and mitigation of toxicity in cells, animals, and humans.

    PubMed

    Friedman, Mendel

    2015-06-01

    Potentially toxic acrylamide is largely derived from the heat-inducing reactions between the amino group of the amino acid asparagine and carbonyl groups of glucose and fructose in plant-derived foods including cereals, coffees, almonds, olives, potatoes, and sweet potatoes. This review surveys and consolidates the following dietary aspects of acrylamide: distribution in food, exposure and consumption by diverse populations, reduction of the content in different food categories, and mitigation of adverse in vivo effects. Methods to reduce acrylamide levels include selecting commercial food with a low acrylamide content, selecting cereal and potato varieties with low levels of asparagine and reducing sugars, selecting processing conditions that minimize acrylamide formation, adding food-compatible compounds and plant extracts to food formulations before processing that inhibit acrylamide formation during processing of cereal products, coffees, teas, olives, almonds, and potato products, and reducing multiorgan toxicity (antifertility, carcinogenicity, neurotoxicity, teratogenicity). The herein described observations and recommendations are of scientific interest for food chemistry, pharmacology, and toxicology, but also have the potential to benefit nutrition, food safety, and human health.

  17. Mechanism of the activation process for the formation of a surface-conduction electron-emitter

    NASA Astrophysics Data System (ADS)

    Tsukamoto, Takeo; Okuda, Masahiro; Arai, Yutaka; Miyata, Hirokatsu

    2016-01-01

    The major role of the chemical reaction between a silica substrate and deposited carbon in the activation process for the formation of a surface-conduction electron emitter (SCE) is investigated. The SCE emits electrons by the tunneling effect when an electric field is applied across a nanoscale gap. The nanogap is spontaneously formed by the activation process, wherein a pulse voltage is applied between a pair of electrodes, which are separated by a narrow gap inside a vacuum chamber in the presence of hydrocarbons. At the gap, two elemental processes compete; the deposition of carbon by the electron-induced decomposition of hydrocarbons and the consumption of carbon by reaction with the silica substrate. The balance of the dynamics of the two processes, which simply depends on the temperature at the gap, is responsible for the spontaneous determination of the width of the nanogap. The calculation based on the model that involves the two competitive processes agrees with the experimental results on the activation process.

  18. Formation of Asymmetrical Structured Silica Controlled by a Phase Separation Process and Implication for Biosilicification

    PubMed Central

    Shi, Jia-Yuan; Yao, Qi-Zhi; Li, Xi-Ming; Zhou, Gen-Tao; Fu, Sheng-Quan

    2013-01-01

    Biogenetic silica displays intricate patterns assembling from nano- to microsize level and interesting non-spherical structures differentiating in specific directions. Several model systems have been proposed to explain the formation of biosilica nanostructures. Of them, phase separation based on the physicochemical properties of organic amines was considered to be responsible for the pattern formation of biosilica. In this paper, using tetraethyl orthosilicate (TEOS, Si(OCH2CH3)4) as silica precursor, phospholipid (PL) and dodecylamine (DA) were introduced to initiate phase separation of organic components and influence silica precipitation. Morphology, structure and composition of the mineralized products were characterized using a range of techniques including field emission scanning electron microscopy (FESEM), transmission electron microscope (TEM), X-ray diffraction (XRD), thermogravimetric and differential thermal analysis (TG-DTA), infrared spectra (IR), and nitrogen physisorption. The results demonstrate that the phase separation process of the organic components leads to the formation of asymmetrically non-spherical silica structures, and the aspect ratios of the asymmetrical structures can be well controlled by varying the concentration of PL and DA. On the basis of the time-dependent experiments, a tentative mechanism is also proposed to illustrate the asymmetrical morphogenesis. Therefore, our results imply that in addition to explaining the hierarchical porous nanopatterning of biosilica, the phase separation process may also be responsible for the growth differentiation of siliceous structures in specific directions. Because organic amine (e.g., long-chair polyamines), phospholipids (e.g., silicalemma) and the phase separation process are associated with the biosilicification of diatoms, our results may provide a new insight into the mechanism of biosilicification. PMID:23585878

  19. Automated system function allocation and display format: Task information processing requirements

    NASA Technical Reports Server (NTRS)

    Czerwinski, Mary P.

    1993-01-01

    An important consideration when designing the interface to an intelligent system concerns function allocation between the system and the user. The display of information could be held constant, or 'fixed', leaving the user with the task of searching through all of the available information, integrating it, and classifying the data into a known system state. On the other hand, the system, based on its own intelligent diagnosis, could display only relevant information in order to reduce the user's search set. The user would still be left the task of perceiving and integrating the data and classifying it into the appropriate system state. Finally, the system could display the patterns of data. In this scenario, the task of integrating the data is carried out by the system, and the user's information processing load is reduced, leaving only the tasks of perception and classification of the patterns of data. Humans are especially adept at this form of display processing. Although others have examined the relative effectiveness of alphanumeric and graphical display formats, it is interesting to reexamine this issue together with the function allocation problem. Currently, Johnson Space Center is the test site for an intelligent Thermal Control System (TCS), TEXSYS, being tested for use with Space Station Freedom. Expert TCS engineers, as well as novices, were asked to classify several displays of TEXSYS data into various system states (including nominal and anomalous states). Three different display formats were used: fixed, subset, and graphical. The hypothesis tested was that the graphical displays would provide for fewer errors and faster classification times by both experts and novices, regardless of the kind of system state represented within the display. The subset displays were hypothesized to be the second most effective display format/function allocation condition, based on the fact that the search set is reduced in these displays. Both the subset and the

  20. Formation of asymmetrical structured silica controlled by a phase separation process and implication for biosilicification.

    PubMed

    Shi, Jia-Yuan; Yao, Qi-Zhi; Li, Xi-Ming; Zhou, Gen-Tao; Fu, Sheng-Quan

    2013-01-01

    Biogenetic silica displays intricate patterns assembling from nano- to microsize level and interesting non-spherical structures differentiating in specific directions. Several model systems have been proposed to explain the formation of biosilica nanostructures. Of them, phase separation based on the physicochemical properties of organic amines was considered to be responsible for the pattern formation of biosilica. In this paper, using tetraethyl orthosilicate (TEOS, Si(OCH2CH3)4) as silica precursor, phospholipid (PL) and dodecylamine (DA) were introduced to initiate phase separation of organic components and influence silica precipitation. Morphology, structure and composition of the mineralized products were characterized using a range of techniques including field emission scanning electron microscopy (FESEM), transmission electron microscope (TEM), X-ray diffraction (XRD), thermogravimetric and differential thermal analysis (TG-DTA), infrared spectra (IR), and nitrogen physisorption. The results demonstrate that the phase separation process of the organic components leads to the formation of asymmetrically non-spherical silica structures, and the aspect ratios of the asymmetrical structures can be well controlled by varying the concentration of PL and DA. On the basis of the time-dependent experiments, a tentative mechanism is also proposed to illustrate the asymmetrical morphogenesis. Therefore, our results imply that in addition to explaining the hierarchical porous nanopatterning of biosilica, the phase separation process may also be responsible for the growth differentiation of siliceous structures in specific directions. Because organic amine (e.g., long-chair polyamines), phospholipids (e.g., silicalemma) and the phase separation process are associated with the biosilicification of diatoms, our results may provide a new insight into the mechanism of biosilicification.

  1. Investigating Processes of Materials Formation via Liquid Phase and Cryogenic TEM

    SciTech Connect

    De Yoreo, James J.; Sommerdijk, Nico

    2016-06-14

    The formation of materials in solutions is a widespread phenomenon in synthetic, biological and geochemical systems, occurring through dynamic processes of nucleation, self-assembly, crystal growth, and coarsening. The recent advent of liquid phase TEM and advances in cryogenic TEM are transforming our understanding of these phenomena by providing new insights into the underlying physical and chemical mechanisms. The techniques have been applied to metallic and semiconductor nanoparticles, geochemical and biological minerals, electrochemical systems, macromolecular complexes, and selfassembling systems, both organic and inorganic. New instrumentation and methodologies currently on the horizon promise new opportunities for advancing the science of materials synthesis.

  2. Analytical Model for Chip Formation in Case of Orthogonal Machining Process

    NASA Astrophysics Data System (ADS)

    Salvatore, Ferdinando; Mabrouki, Tarek; Hamdi, Hédi

    2011-01-01

    The present work deals with the presentation of analytical methodology allowing the modelling of chip formation. For that a "decomposition approach", based on assuming that the material removal is the summation of two contributions: ploughing and pure cut was adopted. Moreover, this analytical model was calibrated by a finite element model and experimental data in terms of temperature and forces evolutions. The global aim is to propose to the industrial community, an efficient rapid-execution analytical model concerning the material removal in the case of an orthogonal cutting process.

  3. Kinetics and microtextures formation during serpentinization: role of grain scale processes and transport

    NASA Astrophysics Data System (ADS)

    malvoisin, B.; Brunet, F.; Carlut, J. H.

    2013-12-01

    Serpentinization of mantle rocks plays a key role on the physical properties of the lithosphere at mid-ocean ridges and in subduction zones. This reaction is controlled by processes occurring at scales ranging from the grain to the lithosphere but the relative importance of these processes on the kinetics and microtextures formation has not been investigated. First, hydrothermal experiments on powders of San Carlos olivine at 500 bars in the 250 - 350 °C range were monitored with a magnetic method to study the kinetics and processes of the reaction at the grain scale. For an initial grain size (IGS) > 5 μm, lizardite, brucite, magnetite and hydrogen formed at a rate one to two orders of magnitude slower than the kinetics used to model serpentinization-related processes. Moreover, the serpentinization rate decreased linearly with the square of the IGS and reaction progress vs. time curves displayed a sigmoid form. The kinetics were controlled by the dissolution of olivine increasing with its reactive surface area which was generated with two cooperating processes (etch pits and grain fracturing) during the first stages of the reaction. Then, hydrothermal experiments were conducted on sintered San Carlos olivine to investigate the role of transport on the reaction. On sintered with a grain size of 1 to 5 μm, low reaction progresses of ~ 3 % in 10 months were obtained and the rate of serpentinization was one order of magnitude slower than on powders and one order of magnitude faster than on a single grain of the size of the sintered. Kinetics were controlled by a coupling between the reaction rate at the grain scale and the rate of fluid pathways formation at grain boundaries. Lizardite precipitated where olivine dissolved whereas magnetite and brucite segregated at the surface of the sintered. These results are in agreement with the observation of magnetite formation and segregation in fractures in naturally serpentinized peridotites and could explain the sparse

  4. Evaluation of the relationship between bulk organic precursors and disinfection byproduct formation for advanced oxidation processes.

    PubMed

    Mayer, Brooke K; Daugherty, Erin; Abbaszadegan, Morteza

    2015-02-01

    Advanced oxidation processes (AOPs) are gaining traction as they offer mineralization potential rather than transferring contaminants between media. However, AOPs operated with limited energy and/or chemical inputs can exacerbate disinfection byproduct (DBP) formation, even as precursors such as dissolved organic carbon, UV254, and specific UV absorbance (SUVA) decrease. This study examined the relationship between DBP precursors and formation using TiO2 photocatalysis experiments, external AOP and non-AOP data, and predictive DBP models. The top-performing indicator, SUVA, generally correlated positively with trihalomethanes and haloacetic acids, but limited-energy photocatalysis yielded contrasting negative correlations. The accuracy of predicted DBP values from models based on bulk parameters was generally poor, regardless of use and extent of AOP treatment and type of source water. Though performance improved for scenarios bounded by conditions used in model development, only 0.5% of the model/dataset pairings satisfied all measured parameter boundary conditions, thereby introducing skepticism toward model usefulness. Study findings suggest that caution should be employed when using bulk indicators and/or models as a metric for AOP mitigation of DBP formation potential, particularly for limited-energy/chemical inputs.

  5. Development of a carbonaceous selective absorber for solar thermal energy collection and process for its formation

    NASA Astrophysics Data System (ADS)

    Garrison, John D.

    1989-02-01

    The main goal of the US Department of Energy supported part of this project is to develop information about controlling the complicated chemical processes involved in the formation of a carbonaceous selective absorber and learn what equipment will allow production of this absorber commercially. The work necessary to accomplish this goal is not yet complete. Formation of the carbonaceous selective absorber in the conveyor oven tried so far has been unsatisfactory, because the proper conditions for applying the carbonaceous coating in each conveyor oven fabricated, either have been difficult to obtain, or have been difficult to maintain over an extended period of time. A new conveyor oven is nearing completion which is expected to allow formation of the carbonaceous selective absorber on absorber tubes in a continuous operation over many days without the necessity of cleaning the conveyor oven or changing the thickness of the electroplated nickel catalyst to compensate for changes in the coating environment in the oven. Work under this project concerned with forming and sealing glass panels to test ideas on evacuated glass solar collector designs and production have been generally quite satisfactory. Delays in completion of the selective absorber work, has caused postponement of the fabrication of a small prototype evacuated glass solar collector panel. Preliminary cost estimates of the selective absorber and solar collector panel indicate that this collector system should be lower in cost than evacuated solar collectors now on the market.

  6. DECIPHERING NATURALLY-OCCURRING PB CONTAMINATION IMPACTING DRINKING WATER WELLS: SHAKER VILLAGE CATCHMENT, MAINE.

    EPA Science Inventory

    Trace Pb concentrations in groundwater within glacial deposits across Maine fluctuate considerably. Deciphering the distribution and sources of naturally occurring Pb in groundwater with only the use of conventional anomaly identification techniques presents a challenge. In a rep...

  7. The Link between Rare-Earth Peak Formation and the Astrophysical Site of the R Process

    NASA Astrophysics Data System (ADS)

    Mumpower, Matthew R.; McLaughlin, Gail C.; Surman, Rebecca; Steiner, Andrew W.

    2016-12-01

    The primary astrophysical source of the rare-earth elements is the rapid neutron capture process (r process). The rare-earth peak that is seen in the solar r-process residuals has been proposed to originate as a pile-up of nuclei during the end of the r process. We introduce a new method utilizing Monte Carlo studies of nuclear masses in the rare-earth region, that includes self-consistently adjusting β-decay rates and neutron capture rates, to find the mass surfaces necessary for the formation of the rare-earth peak. We demonstrate our method with two types of astrophysical scenario, one corresponding to conditions typical of hot winds from core-collapse supernovae and stellar-mass accretion disks, and one corresponding to conditions typical of the ejection of the material from the tidal tails of neutron star mergers. In each type of astrophysical condition, this method successfully locates a region of enhanced stability in the mass surface that is responsible for the rare-earth peak. For each scenario, we find that the change in the mass surface has qualitatively different features, thus future measurements can shed light on the type of environment in which the r process occurred.

  8. Analysis of glow discharges for understanding the process of film formation

    NASA Technical Reports Server (NTRS)

    Venugopalan, M.; Avni, R.

    1984-01-01

    The physical and chemical processes which occur during the formation of different types of films in a variety of glow discharge plasmas are discussed. Emphasis is placed on plasma diagnostic experiments using spectroscopic methods, probe analysis, mass spectrometric sampling and magnetic resonance techniques which are well suited to investigate the neutral and ionized gas phase species as well as some aspects of plasma surface interactions. The results on metallic, semi-conducting and insulating films are reviewed in conjunction with proposed models and the problem encountered under film deposition conditions. It is concluded that the understanding of film deposition process requires additional experimental information on plasma surface interactions of free radicals and the synergetic effects where photon, electron and ion bombardment change the reactivity of the incident radical with the surface.

  9. Numerical Simulation of the Processes of Icing on Airfoils with Formation of a "Barrier" Ice

    NASA Astrophysics Data System (ADS)

    Prikhod'ko, A. A.; Alekseenko, S. V.

    2014-05-01

    Software and methods allowing one to model the processes of formation of a "barrier" ice on the unprotected part of an airfoil have been developed with the use of the Reynolds-averaged Navier-Stokes equations for a compressible gas, which are closed with the aid of the Spalart-Allmaras model of turbulence. An inertial model is used to describe the motion of overcooled water droplets. In modeling the process of ice accretion, differential equations of mass, momentum, and energy conservation are used for each element of the surface. The initial equations are made discrete by means of the control volume approach. The influence of the height of ice accretions and of their location on the character of air-droplet flow past a NACA 0012 airfoil and on its aerodynamic characteristics has been analyzed.

  10. Kinetics of the process of formation and high-temperature oxidation of electrospark coatings on steel

    SciTech Connect

    Verkhoturov, A.D.; Chiplik, V.N.; Egorov, F.F.; Lavrenko, V.A.; Podchernyaeva, I.A.; Shemet, V.Z.

    1986-10-01

    This work is a study of the kinetics of formation and of the heat resistance of electrospark coatings based on the composite TiB/sub 2/-Mo with varying molybdenum content. In the process of electrospark alloying they measured the specific erosion of the anode and the increase in weight of the cathode with an accuracy not worse than 5%. Electrospark coatings of TiB/sub 2/-Mo on steel 45 are marked by improved scaling resistance at temperatures above 900 C. Their scaling resistance and also the effectiveness of the process of electrospark alloying increase with increasing content of the phase B-MoB in the coating because molybdenum borate forms during its high-temperature oxidation. Illustrations and table are included.

  11. Model of the accumulation process in the formation of planetary systems. I. Numerical experiments

    SciTech Connect

    Eneev, T.M.; Kozlov, N.N.

    1981-04-01

    This work considers the evolution of a plane protoplanetary nebula consisting of a large number of bodies (protoplanets), which interact gravitationally, combine on contact, and move in the field of a massive central body (the sun or a planet). It is assumed that the gravitational interaction between bodies occurs only during their binary close approach. It is also assumed that the bodies move in Keplerian orbits between close approaches and that the orbits of all the bodies are circular at the initial time of evolution of the cloud. The so-called limit model of the accumulation process, in which each close approach of bodies is terminated by their combining, is considered. It is shown that in the course of evolution of such a model there appear annular zones of material condensation whose subsequent development leads to the formation of planets with predominantly direct rotation about their axes. The principal numerical results are obtained by computer simulation of the planetary accumulation process.

  12. Ventifact Formation in the Mojave Desert: Field Analogs for Martian Processes

    NASA Technical Reports Server (NTRS)

    Laity, J. E.; Bridges, N. T.; Boyle, T. K.

    2001-01-01

    Two field studies in the Mojave Desert, California, shed light on processes of ventifact formation. The field sites are located on a ridge at Little Cowhole Mountain, which lies approximately 12 km south of Baker, and on an unnamed ridge situated along the northern boundary of the Mojave River Sink (Rasor Road site). The rocks at Little Cowhole Mountain are a blue-grey marble/dolomite, whereas those at Rasor Road are Miocene volcanic rocks (basalt). At both sites the abrasive agent is a fine-grained aeolian sand which was probably derived largely from the Mojave River. There are minimal modem inputs of sand to either site: abrasion occurs as a result of unique climatic and topographic conditions which allow pre-existing sand to be recycled from one aspect of the ridge to the other. Climatic conditions are well suited for ventifact formation. Owing, to the dry climate (marked by low average relative humidity, infrequent dew, and low annual rainfall), rates of chemical weathering are low. Where resurfacing of the rocks by sand abrasion proceeds at a rate greater than weathering, the ventifacts are considered "active." Active ventifacts are found atop and straddling the ridge crests, in the zone of maximum wind velocity and sediment supply. Inactive ventifacts occur where modem weathering Processes exceed abrasion rates; principally on the basal two-thirds of the hillslope, where wind velocity and sediment supply are lower. At intermediate locations between the slope base and crest, ventifacts are either active or inactive, depending on local conditions. The presence of relict ventifacts at the study sites, as well as elsewhere in the eastern Mojave Desert, suggests that the conditions for venti fact formation must have been more intense and extensive in the past. Together, the studies illustrate that the processes that interact to form ventifacts are highly complex, and must be studied at many scales. Small-scale effects, such as local topography, plant cover, or

  13. Tromantadine inhibits HSV-1 induced syncytia formation and viral glycoprotein processing

    SciTech Connect

    Ickes, D.E.

    1989-01-01

    Tromantadine inhibits a late event in Herpes Simplex Virus Type 1 (HSV-1) replication, visualized by the inhibition of both the size and number of syncytia. Tromantadine can be added at any time between 1 and 9 h post infection with complete inhibition of syncytia formation. Glycan synthesis of the viral glycoproteins, important for syncytia formation, is incomplete due to tromantadine treatment. Tromantadine does not inhibit the initiation of glycosylation, since viral glycoproteins, gX{sub t}, synthesized in the presence of tromantadine still incorporate {sup 3}H-glucosamine. Tromantadine does not inhibit the transport of t e viral glycoproteins to the cell surface, since glycoproteins B, C, and D are expressed, as demonstrated by immunofluorescence. Tromantadine inhibition of HSV-1 glycoprotein processing is demonstrated by an increase in mobility of the radioimmunoprecipitated gX{sub t}, on SDS-PAGE. The gX{sub t} of KOS, a non-syncytial strain of HSV-1, had a similar increase in mobility, suggesting that the block in glycoprotein processing is a general effect of tromantadine treatment. Fucose, which is incorporated into oligosaccharides in the medial Golgi, is incorporated into gX{sub t}, indicating that the tromantadine block in glycoprotein processing occurs after this step. Lectin binding studies and SDS-PAGE analysis of gC processed in the presence of tromantadine, gC{sub t}, indicates that it has terminal galactose residues in both N- and O-linked glycans (binds Peanut and Ricin Agglutinins, respectively). The inhibition of sialylation of N-linked glycans by tromantadine was indicated by the extent of the increase in SDS-PAGE mobility of the G protein from Vesicular Stomatitis Virus. O-glycanase digestion and SDS-PAGE analysis of gC{sub t} indicate that the O-linked disaccharide NAcGal-Galactose is present.

  14. MODELING THE FORMATION OF GIANT PLANET CORES. I. EVALUATING KEY PROCESSES

    SciTech Connect

    Levison, Harold F.; Thommes, Edward; Duncan, Martin J.

    2010-04-15

    One of the most challenging problems we face in our understanding of planet formation is how Jupiter and Saturn could have formed before the solar nebula dispersed. The most popular model of giant planet formation is the so-called core accretion model. In this model a large planetary embryo formed first, mainly by two-body accretion. This is then followed by a period of inflow of nebular gas directly onto the growing planet. The core accretion model has an Achilles heel, namely the very first step. We have undertaken the most comprehensive study of this process to date. In this study, we numerically integrate the orbits of a number of planetary embryos embedded in a swarm of planetesimals. In these experiments, we have included a large number of physical processes that might enhance accretion. In particular, we have included (1) aerodynamic gas drag, (2) collisional damping between planetesimals, (3) enhanced embryo cross sections due to their atmospheres, (4) planetesimal fragmentation, and (5) planetesimal-driven migration. We find that the gravitational interaction between the embryos and the planetesimals leads to the wholesale redistribution of material-regions are cleared of material and gaps open near the embryos. Indeed, in 90% of our simulations without fragmentation, the region near those embryos is cleared of planetesimals before much growth can occur. Thus, the widely used assumption that the surface density distribution of planetesimals is smooth can lead to misleading results. In the remaining 10% of our simulations, the embryos undergo a burst of outward migration that significantly increases growth. On timescales of {approx}10{sup 5} years, the outer embryo can migrate {approx}6 AU and grow to roughly 30 M {sub +}. This represents a largely unexplored mode of core formation. We also find that the inclusion of planetesimal fragmentation tends to inhibit growth except for a narrow range of fragment migration rates.

  15. [Formation process of nitrogenous disinfection byproduct trichloronitromethane in drinking water and its influencing factors].

    PubMed

    Ding, Chun-Sheng; Zou, Bang-Wen; Miao, Jia; Fu, Yang-Ping; Shen, Jia-Chen

    2013-08-01

    A novel method is described in this paper, which uses methyl tertiary butyl ether (MTBE) as extractant and 1,2-dibromopropane as internal standard for the determination of nitrogenous disinfection byproduct trichloronitromethane (TCNM) by gas chromatography mass spectrometry (GC-MS). The formation process of TCNM and its influencing factors were evaluated with methylamine as the precursor during chlorination. The results indicated that the TCNM amount produced under alkaline condition was higher than those produced under the neutral and acidic conditions, and the TCNM amount increased with the increase of pH value. It was found that the TCNM amount increased with the increase of chlorine addition when the chlorine dosage was in the range of 2-8 mmol x L(-1). However, the TCNM amount was reduced when the chlorine dosage was enhanced from 8 mmol x L(-1) to 12 mmol x L(-1), under which conditions the concentration of free chlorine was higher and methylamine was turned into nitriles and aldehydes through other reactions. It was also found that the TCNM amount increased with the increase of methylamine addition when the methylamine dosage was in the range of 0.5-4 mmol x L(-1). Temperature was another important factor that affected the TCNM formation from methylamine especially in the range of 10-30 degrees C and the higher the temperature, the more the TCNM amount produced. The formation process of TCNM from methylamine by chlorination was in accordance with the mechanism of an electrophilic reaction, in which HClO and ClO(-) could be used as the electrophilic reagents to attack methylamine and then to form TCNM.

  16. Processes of annual moraine formation at a temperate alpine valley glacier: glacier dynamics and climatic controls

    NASA Astrophysics Data System (ADS)

    Lukas, S.

    2012-04-01

    This paper presents the first detailed sedimentological study of annual moraines formed by an alpine valley glacier. The moraines have been formed since at least AD 1980 by a subsidiary lobe of Gornergletscher, Switzerland, that advances up a reverse bedrock slope. They reach heights of 0.5-1.5 m, widths of up to 6 m and lengths of up to several hundreds of metres. Sediments in these moraines comprise proglacial outwash and debris flow units; subglacial traction till is absent entirely. Based on four representative sections, three genetic process combinations have been identified. (1) Inefficient bulldozing of a gently-sloping ice margin transfers proglacial sediments onto the ice, causing differential ablation and dead-ice incorporation upon retreat. (2) Terrestrial ice-contact fans are formed by the dumping of englacial and supraglacial material from point sources such as englacial conduit fills. Debris flows and associated fluvial sediments are stacked against a temporarily stationary margin at the start, and deformed during glacier advance in the remainder, of the accumulation season. (3) A steep ice margin without supraglacial input leads to efficient bulldozing and deformation of pre-existing foreland sediments by wholesale folding. Ice surface slope appears to be a key control on the type of process responsible for moraine formation in any given place and year. The second and third modes result in stable and higher moraines that have a higher preservation potential than those containing dead ice. Analysis of the spacing and climatic records at Gornergletscher reveal that winter temperature controls marginal retreat and hence moraine formation. However, any climatic signal is complicated by other factors, most notably the presence of a reverse bedrock slope, so that the extraction of a clear climatic signal is not straightforward. This study highlights the complexity of annual moraine formation in high-mountain environments and suggests avenues for further

  17. Formation of nanoporous pyrobitumen residues during maturation processes within the Barnett Shale (Fort Worth Basin)

    NASA Astrophysics Data System (ADS)

    Bernard, S.; Wirth, R.; Schreiber, A.; Schulz, H.-M.; Horsfield, B.

    2012-04-01

    Hydrocarbon generation processes occur within organic-rich shales as a response to increases in thermal maturation. Shale gas reservoir quality is thought to be largely dependent on the extent to which solid organic material has been converted to pore space during catagenesis. Although pores may drastically vary in variety and abundance within differing shales, the occurrence of nanopores within organic particles has recently been documented for an important number of gas shale systems (i.e., Barnett, Haynesville, Utica, Eagle Ford, Woodford, Horn River, Marcellus, Posidonia …). However, despite their ubiquitous nature, the formation and the geochemical nature of these nanoporous organic compounds remain unclear. Here, we present the characterization of samples from the organic-rich Mississippian Barnett shale gas system (Fort Worth Basin, Texas, USA) at varying stages of thermal maturation. Using a combination of compositional organic geochemistry and spectromicroscopy techniques, including synchrotron-based scanning transmission X-ray microscopy (STXM - data collected using the CLS 10ID-1 STXM beamline) and transmission electron microscopy (TEM), we document a net increase in sample geochemical heterogeneity with increasing maturity. In addition to the presence of bitumen in samples of oil window maturity, very likely genetically derived from thermally degraded kerogen, the formation of nanoporous pyrobitumen has been inferred for samples of gas window maturity, likely resulting from the formation of gaseous hydrocarbons by secondary cracking of bitumen compounds. By providing in-situ insights into the fate of bitumen and pyrobitumen as a response to the thermal evolution of the macromolecular structure of kerogen, the present contribution constitutes an important step towards better constraining hydrocarbon generation processes occurring within unconventional gas shale systems.

  18. Effect of annealing process on the phase formation in poly(vinylidene fluoride) thin films

    SciTech Connect

    Abdullah, Ibtisam Yahya; Yahaya, Muhammad; Jumali, Mohd Hafizuddin Haji; Shanshool, Haider Mohammed

    2014-09-03

    This work reports the initial study on the effect of annealing process on the crystalline phase of poly(vinylidene fluoride) (PVDF) thin film. PVDF powder was dissolved in N,N-dimethylformamide before spin-coated onto a glass substrate to form a film. The films were annealed at 30°C, 90°C and 110°C for 5 hrs. The crystalline phase of the powder PVDF as received was investigated by using XRD and FTIR techniques. Moreover, the crystalline phases of thin films after annealing were investigated by using the same techniques. XRD analysis showed that in powder form PVDF exists in α-phase. Each annealed PVDF thin films exhibited identical formation of three-phases material namely γ (as major phase) while α and β phases as the minor phases. The FTIR analysis showed that the powder form of PVDF exists in α and β phases. FTIR measurement further confirmed the XRD results implying that the annealing process has no significant effect on the phase formation in PVDF films.

  19. E-cadherin junction formation involves an active kinetic nucleation process

    SciTech Connect

    Biswas, Kabir H.; Hartman, Kevin L.; Yu, Cheng -han; Harrison, Oliver J.; Song, Hang; Smith, Adam W.; Huang, William Y. C.; Lin, Wan -Chen; Guo, Zhenhuan; Padmanabhan, Anup; Troyanovsky, Sergey M.; Dustin, Michael L.; Shapiro, Lawrence; Honig, Barry; Zaidel-Bar, Ronen; Groves, Jay T.

    2015-08-19

    Epithelial (E)-cadherin-mediated cell–cell junctions play important roles in the development and maintenance of tissue structure in multicellular organisms. E-cadherin adhesion is thus a key element of the cellular microenvironment that provides both mechanical and biochemical signaling inputs. Here, we report in vitro reconstitution of junction-like structures between native E-cadherin in living cells and the extracellular domain of E-cadherin in a supported membrane. Junction formation in this hybrid live cell-supported membrane configuration requires both active processes within the living cell and a supported membrane with low E-cad-ECD mobility. The hybrid junctions recruit α-catenin and exhibit remodeled cortical actin. Observations suggest that the initial stages of junction formation in this hybrid system depend on the trans but not the cis interactions between E-cadherin molecules, and proceed via a nucleation process in which protrusion and retraction of filopodia play a key role.

  20. Magneto-optical indicator film study of the hybrid exchange spring formation and evolution processes

    NASA Astrophysics Data System (ADS)

    Nikitenko, V. I.; Gornakov, V. S.; Kabanov, Yu. P.; Shapiro, A. J.; Shull, R. D.; Chien, C. L.; Jiang, J. S.; Bader, S. D.

    2003-03-01

    The elementary events of the remagnetization processes in nanocomposite magnetic bilayers were investigated using iron-garnet indicator films with in-plane anisotropy. We have observed hybrid domain walls consisting of both ferromagnetic and antiferromagnetic sections perpendicular to the interface. The external magnetic field shifts only the ferromagnetic part of the domain walls. This leads to the formation of a hybrid exchange spin spring parallel to the interface. The processes of spring nucleation and untwisting occur at different locations. With the field oriented antiparallel to the macroscopic unidirectional anisotropy, remagnetization of the soft ferromagnet layer in the hard/soft nanocomposite starts by the formation of an exchange spring consisting of micrometer-scale sub-domains with opposite direction spin twisting. A rotating magnetic field (smaller than some critical value) creates firstly a single-chiral spin spiral; this spiral then loses stability, incoherently untwists and gradually inverts its chirality with increasing field rotation. Untwisting of the hybrid exchange spring at higher fields leads to the creation of unusual hybrid non-180° domain walls. The initial (ground) state of the bilayer with such noncollinear magnetized domains is not restored after stopping the field rotation and returning it to zero. The revealed phenomena are attributed to the influence of the dispersion in the unidirectional anisotropy induced by magnetization frustration in the interface and bilayer crystal lattice defects.

  1. Effects of stacking fault energy on defect formation process in face-centered cubic metals

    NASA Astrophysics Data System (ADS)

    Okita, Taira; Yang, Yingjuan; Hirabayashi, Junichi; Itakura, Mitsuhiro; Suzuki, Katsuyuki

    2016-05-01

    To elucidate the effect of stacking fault energies (SFEs) on defect formation by the collision cascade process for face-centred cubic metals, we used six sets of interatomic potentials with different SFEs while keeping the other properties almost identical. Molecular dynamic simulations of the collision cascade were carried out using these potentials with primary knock-on atom energies (EPKA) of 10 and 20 keV at 100 K. Neither the number of residual defects nor the size distributions for both self-interstitial atom (SIA) type and vacancy type clusters were affected by the difference in the SFE. In the case of EPKA = 20 keV, the ratio of glissile SIA clusters increased as the SFE decreased, which was not expected by a prediction based on the classical dislocation theory. The trend did not change after annealing at 1100 K for 100 ps. For vacancy clusters, few stacking fault tetrahedrons (SFTs) formed before the annealing. However, lower SFEs tended to increase the SFT fraction after the annealing, where large vacancy clusters formed at considerable densities. The findings of this study can be used to characterise the defect formation process in low SFE metals such as austenitic stainless steels.

  2. Level of processing modulates the neural correlates of emotional memory formation.

    PubMed

    Ritchey, Maureen; LaBar, Kevin S; Cabeza, Roberto

    2011-04-01

    Emotion is known to influence multiple aspects of memory formation, including the initial encoding of the memory trace and its consolidation over time. However, the neural mechanisms whereby emotion impacts memory encoding remain largely unexplored. The present study used a levels-of-processing manipulation to characterize the impact of emotion on encoding with and without the influence of elaborative processes. Participants viewed emotionally negative, neutral, and positive scenes under two conditions: a shallow condition focused on the perceptual features of the scenes and a deep condition that queried their semantic meaning. Recognition memory was tested 2 days later. Results showed that emotional memory enhancements were greatest in the shallow condition. fMRI analyses revealed that the right amygdala predicted subsequent emotional memory in the shallow more than deep condition, whereas the right ventrolateral PFC demonstrated the reverse pattern. Furthermore, the association of these regions with the hippocampus was modulated by valence: the amygdala-hippocampal link was strongest for negative stimuli, whereas the prefrontal-hippocampal link was strongest for positive stimuli. Taken together, these results suggest two distinct activation patterns underlying emotional memory formation: an amygdala component that promotes memory during shallow encoding, especially for negative information, and a prefrontal component that provides extra benefits during deep encoding, especially for positive information.

  3. E-cadherin junction formation involves an active kinetic nucleation process

    DOE PAGES

    Biswas, Kabir H.; Hartman, Kevin L.; Yu, Cheng -han; ...

    2015-08-19

    Epithelial (E)-cadherin-mediated cell–cell junctions play important roles in the development and maintenance of tissue structure in multicellular organisms. E-cadherin adhesion is thus a key element of the cellular microenvironment that provides both mechanical and biochemical signaling inputs. Here, we report in vitro reconstitution of junction-like structures between native E-cadherin in living cells and the extracellular domain of E-cadherin in a supported membrane. Junction formation in this hybrid live cell-supported membrane configuration requires both active processes within the living cell and a supported membrane with low E-cad-ECD mobility. The hybrid junctions recruit α-catenin and exhibit remodeled cortical actin. Observations suggest thatmore » the initial stages of junction formation in this hybrid system depend on the trans but not the cis interactions between E-cadherin molecules, and proceed via a nucleation process in which protrusion and retraction of filopodia play a key role.« less

  4. Neural Correlates of Auditory Processing, Learning and Memory Formation in Songbirds

    NASA Astrophysics Data System (ADS)

    Pinaud, R.; Terleph, T. A.; Wynne, R. D.; Tremere, L. A.

    Songbirds have emerged as powerful experimental models for the study of auditory processing of complex natural communication signals. Intact hearing is necessary for several behaviors in developing and adult animals including vocal learning, territorial defense, mate selection and individual recognition. These behaviors are thought to require the processing, discrimination and memorization of songs. Although much is known about the brain circuits that participate in sensorimotor (auditory-vocal) integration, especially the ``song-control" system, less is known about the anatomical and functional organization of central auditory pathways. Here we discuss findings associated with a telencephalic auditory area known as the caudomedial nidopallium (NCM). NCM has attracted significant interest as it exhibits functional properties that may support higher order auditory functions such as stimulus discrimination and the formation of auditory memories. NCM neurons are vigorously dr iven by auditory stimuli. Interestingly, these responses are selective to conspecific, relative to heterospecific songs and artificial stimuli. In addition, forms of experience-dependent plasticity occur in NCM and are song-specific. Finally, recent experiments employing high-throughput quantitative proteomics suggest that complex protein regulatory pathways are engaged in NCM as a result of auditory experience. These molecular cascades are likely central to experience-associated plasticity of NCM circuitry and may be part of a network of calcium-driven molecular events that support the formation of auditory memory traces.

  5. Numerical analysis of the formation process of aerosols in the alveoli

    NASA Astrophysics Data System (ADS)

    Haslbeck, Karsten; Seume, Jörg R.

    2008-11-01

    For a successful diagnosis of lung diseases through an analysis of non-volatile molecules in the exhaled breath, an exact understanding of the aerosol formation process is required. This process is modeled using Computational Fluid Dynamics (CFD). The model shows the interaction of the boundary surface between the streamed airway and the local epithelial liquid layer. A 2-D volume mesh of an alveolus is generated by taking into account the connection of the alveoli with the sacculi alveolares (SA). The Volume of Fluid (VOF) Method is used to model the interface between the gas and the liquid film. The non-Newtonian flow is modeled by the implementation of the Ostwald de Waele model. Surface tension is a function of the surfactant concentration. The VOF-Method allows the distribution of the concentration of the epithelial liquid layer at the surface to be traced in a transient manner. The simulations show the rupturing of the liquid film through the drop formation. Aerosol particles are ejected into the SA and do not collide with the walls. The quantity, the geometrical size as well as the velocity distributions of the generated aerosols are determined. The data presented in the paper provide the boundary conditions for future CFD analysis of the aerosol transport through the airways up to exhalation.

  6. Formation process of TiO2 nanotube arrays prepared by anodic oxidation method.

    PubMed

    Li, Hongyi; Liu, Man; Wang, Hong; Wu, Junshu; Su, Penglei; Li, Dasheng; Wang, Jinshu

    2013-06-01

    TiO2 nanotube array thin films have great potential in many fields, such as solar cell, photo catalyst, photo-induced cathodic protection for metals and bioactivity. In order to investigate the formation process of the TiO2 nanotube array thin films, the EIS spectrum and current density were measured during the anodic oxidation. The results showed that the formation process could be divided into four stages. The current density decreased sharply at the first stage, and then increased at the second stage, followed by declining and finally remained constant value. In addition, the current density increased with the anodic voltage. The EIS spectrum varied in different stage. The simulated circuit was composed three sections, the first sections indicated the resistance of the electrolyte, the second one gave the double layer structure between the electrolyte and titanium electrode, the third one was a inductive loop, which represented the anions absorbed on the surface of the TiO2 nanotube's wall. The more cations were absorbed, the higher value of the inductive loop would be. The EIS results showed that the value increased with the outer voltage, which means that more cations were absorbed under the higher anodic voltage.

  7. Processes and controlling factors of polygenetic dolomite formation in the Transdanubian Range, Hungary: a synopsis

    NASA Astrophysics Data System (ADS)

    Haas, János; Hips, Kinga; Budai, Tamás; Győri, Orsolya; Lukoczki, Georgina; Kele, Sándor; Demény, Attila; Poros, Zsófia

    2016-06-01

    In the Transdanubian Range (Hungary), dolostone and dolomitic limestone appear in a number of sedimentary successions formed from the Late Permian to the Late Triassic in various depositional settings and under various diagenetic conditions, whereas only a negligible amount of dolomite was detected in the post-Triassic formations. Seven dolomite-bearing units representing ramp, small and large carbonate platforms, and intraplatform basin settings are presented in this synopsis. In most cases, multi-stage and polygenetic dolomitization was inferred. The main mass of the dolostones was formed via near-surface diagenetic processes, which were commonly preceded by the formation of synsedimentary dolomite. Accordingly, surficial conditions that prevailed during sediment deposition controlled the dolomite-forming processes and thus the lateral extension and the time span of dolomitization. The area of episodic subaerial exposure was a critical controlling factor of the lateral extension of the near-surface dolomite genesis, whereas its temporal extension was mostly governed by climate. Burial diagenesis usually resulted in only moderate dolomitization, either in connection with compactional fluid flow or via thermal convection. The Triassic fault zones provided conduits for fluid flow that led to both replacive dolomitization and dolomite cement precipitation. In the Late Triassic extensional basins, synsedimentary fault-controlled dolomitization of basinal deposits was reconstructed.

  8. Deciphering modular and dynamic behaviors of transcriptional networks.

    PubMed

    Zhan, Ming

    2007-01-01

    The coordinated and dynamic modulation or interaction of genes or proteins acts as an important mechanism used by a cell in functional regulation. Recent studies have shown that many transcriptional networks exhibit a scale-free topology and hierarchical modular architecture. It has also been shown that transcriptional networks or pathways are dynamic and behave only in certain ways and controlled manners in response to disease development, changing cellular conditions, and different environmental factors. Moreover, evolutionarily conserved and divergent transcriptional modules underline fundamental and species-specific molecular mechanisms controlling disease development or cellular phenotypes. Various computational algorithms have been developed to explore transcriptional networks and modules from gene expression data. In silico studies have also been made to mimic the dynamic behavior of regulatory networks, analyzing how disease or cellular phenotypes arise from the connectivity or networks of genes and their products. Here, we review the recent development in computational biology research on deciphering modular and dynamic behaviors of transcriptional networks, highlighting important findings. We also demonstrate how these computational algorithms can be applied in systems biology studies as on disease, stem cells, and drug discovery.

  9. Deciphering tissue-induced Klebsiella pneumoniae lipid A structure.

    PubMed

    Llobet, Enrique; Martínez-Moliner, Verónica; Moranta, David; Dahlström, Käthe M; Regueiro, Verónica; Tomás, Anna; Cano, Victoria; Pérez-Gutiérrez, Camino; Frank, Christian G; Fernández-Carrasco, Helena; Insua, José Luis; Salminen, Tiina A; Garmendia, Junkal; Bengoechea, José A

    2015-11-17

    The outcome of an infection depends on host recognition of the pathogen, hence leading to the activation of signaling pathways controlling defense responses. A long-held belief is that the modification of the lipid A moiety of the lipopolysaccharide could help Gram-negative pathogens to evade innate immunity. However, direct evidence that this happens in vivo is lacking. Here we report the lipid A expressed in the tissues of infected mice by the human pathogen Klebsiella pneumoniae. Our findings demonstrate that Klebsiella remodels its lipid A in a tissue-dependent manner. Lipid A species found in the lungs are consistent with a 2-hydroxyacyl-modified lipid A dependent on the PhoPQ-regulated oxygenase LpxO. The in vivo lipid A pattern is lost in minimally passaged bacteria isolated from the tissues. LpxO-dependent modification reduces the activation of inflammatory responses and mediates resistance to antimicrobial peptides. An lpxO mutant is attenuated in vivo thereby highlighting the importance of this lipid A modification in Klebsiella infection biology. Colistin, one of the last options to treat multidrug-resistant Klebsiella infections, triggers the in vivo lipid A pattern. Moreover, colistin-resistant isolates already express the in vivo lipid A pattern. In these isolates, LpxO-dependent lipid A modification mediates resistance to colistin. Deciphering the lipid A expressed in vivo opens the possibility of designing novel therapeutics targeting the enzymes responsible for the in vivo lipid A pattern.

  10. Deciphering tissue-induced Klebsiella pneumoniae lipid A structure

    PubMed Central

    Llobet, Enrique; Martínez-Moliner, Verónica; Moranta, David; Dahlström, Käthe M.; Regueiro, Verónica; Tomás, Anna; Cano, Victoria; Pérez-Gutiérrez, Camino; Frank, Christian G.; Fernández-Carrasco, Helena; Insua, José Luis; Salminen, Tiina A.; Garmendia, Junkal; Bengoechea, José A.

    2015-01-01

    The outcome of an infection depends on host recognition of the pathogen, hence leading to the activation of signaling pathways controlling defense responses. A long-held belief is that the modification of the lipid A moiety of the lipopolysaccharide could help Gram-negative pathogens to evade innate immunity. However, direct evidence that this happens in vivo is lacking. Here we report the lipid A expressed in the tissues of infected mice by the human pathogen Klebsiella pneumoniae. Our findings demonstrate that Klebsiella remodels its lipid A in a tissue-dependent manner. Lipid A species found in the lungs are consistent with a 2-hydroxyacyl-modified lipid A dependent on the PhoPQ-regulated oxygenase LpxO. The in vivo lipid A pattern is lost in minimally passaged bacteria isolated from the tissues. LpxO-dependent modification reduces the activation of inflammatory responses and mediates resistance to antimicrobial peptides. An lpxO mutant is attenuated in vivo thereby highlighting the importance of this lipid A modification in Klebsiella infection biology. Colistin, one of the last options to treat multidrug-resistant Klebsiella infections, triggers the in vivo lipid A pattern. Moreover, colistin-resistant isolates already express the in vivo lipid A pattern. In these isolates, LpxO-dependent lipid A modification mediates resistance to colistin. Deciphering the lipid A expressed in vivo opens the possibility of designing novel therapeutics targeting the enzymes responsible for the in vivo lipid A pattern. PMID:26578797

  11. The significance of ACTH for the process of formation of complex heparin compounds in the blood during immobilization stress

    NASA Technical Reports Server (NTRS)

    Kudryashov, B. A.; Shapiro, F. B.; Lomovskaya, F. B.; Lyapina, L. A.

    1979-01-01

    Adrenocorticotropin (ACTH) was administered to rats at different times following adrenalectomy. Adrenocorticotropin caused a significant increase in the formation of heparin complexes even in the absence of stress factor. When ACTH secretion is blocked, immobilization stress is not accompanied by an increase in the process of complex formation. The effect of ACTH on the formation of heparin complexes was mediated through its stimulation of the adrenal cortex.

  12. Flame Experiments at the Advanced Light Source: New Insights into Soot Formation Processes

    PubMed Central

    Hansen, Nils; Skeen, Scott A.; Michelsen, Hope A.; Wilson, Kevin R.; Kohse-Höinghaus, Katharina

    2014-01-01

    The following experimental protocols and the accompanying video are concerned with the flame experiments that are performed at the Chemical Dynamics Beamline of the Advanced Light Source (ALS) of the Lawrence Berkeley National Laboratory1-4. This video demonstrates how the complex chemical structures of laboratory-based model flames are analyzed using flame-sampling mass spectrometry with tunable synchrotron-generated vacuum-ultraviolet (VUV) radiation. This experimental approach combines isomer-resolving capabilities with high sensitivity and a large dynamic range5,6. The first part of the video describes experiments involving burner-stabilized, reduced-pressure (20-80 mbar) laminar premixed flames. A small hydrocarbon fuel was used for the selected flame to demonstrate the general experimental approach. It is shown how species’ profiles are acquired as a function of distance from the burner surface and how the tunability of the VUV photon energy is used advantageously to identify many combustion intermediates based on their ionization energies. For example, this technique has been used to study gas-phase aspects of the soot-formation processes, and the video shows how the resonance-stabilized radicals, such as C3H3, C3H5, and i-C4H5, are identified as important intermediates7. The work has been focused on soot formation processes, and, from the chemical point of view, this process is very intriguing because chemical structures containing millions of carbon atoms are assembled from a fuel molecule possessing only a few carbon atoms in just milliseconds. The second part of the video highlights a new experiment, in which an opposed-flow diffusion flame and synchrotron-based aerosol mass spectrometry are used to study the chemical composition of the combustion-generated soot particles4. The experimental results indicate that the widely accepted H-abstraction-C2H2-addition (HACA) mechanism is not the sole molecular growth process responsible for the formation of the

  13. Flame experiments at the advanced light source: new insights into soot formation processes.

    PubMed

    Hansen, Nils; Skeen, Scott A; Michelsen, Hope A; Wilson, Kevin R; Kohse-Höinghaus, Katharina

    2014-05-26

    The following experimental protocols and the accompanying video are concerned with the flame experiments that are performed at the Chemical Dynamics Beamline of the Advanced Light Source (ALS) of the Lawrence Berkeley National Laboratory(1-4). This video demonstrates how the complex chemical structures of laboratory-based model flames are analyzed using flame-sampling mass spectrometry with tunable synchrotron-generated vacuum-ultraviolet (VUV) radiation. This experimental approach combines isomer-resolving capabilities with high sensitivity and a large dynamic range(5,6). The first part of the video describes experiments involving burner-stabilized, reduced-pressure (20-80 mbar) laminar premixed flames. A small hydrocarbon fuel was used for the selected flame to demonstrate the general experimental approach. It is shown how species' profiles are acquired as a function of distance from the burner surface and how the tunability of the VUV photon energy is used advantageously to identify many combustion intermediates based on their ionization energies. For example, this technique has been used to study gas-phase aspects of the soot-formation processes, and the video shows how the resonance-stabilized radicals, such as C3H3, C3H5, and i-C4H5, are identified as important intermediates(7). The work has been focused on soot formation processes, and, from the chemical point of view, this process is very intriguing because chemical structures containing millions of carbon atoms are assembled from a fuel molecule possessing only a few carbon atoms in just milliseconds. The second part of the video highlights a new experiment, in which an opposed-flow diffusion flame and synchrotron-based aerosol mass spectrometry are used to study the chemical composition of the combustion-generated soot particles(4). The experimental results indicate that the widely accepted H-abstraction-C2H2-addition (HACA) mechanism is not the sole molecular growth process responsible for the formation

  14. Microemulsions and Aggregation Formation in Extraction Processes for Used Nuclear Fuel: Thermodynamic and Structural Studies

    SciTech Connect

    Nilsson, Mikael

    2016-05-04

    Advanced nuclear fuel cycles rely on successful chemical separation of various elements in the used fuel. Numerous solvent extraction (SX) processes have been developed for the recovery and purification of metal ions from this used material. However, the predictability of process operations has been challenged by the lack of a fundamental understanding of the chemical interactions in several of these separation systems. For example, gaps in the thermodynamic description of the mechanism and the complexes formed will make predictions very challenging. Recent studies of certain extraction systems under development and a number of more established SX processes have suggested that aggregate formation in the organic phase results in a transformation of its selectivity and efficiency. Aggregation phenomena have consistently been interfering in SX process development, and have, over the years, become synonymous with an undesirable effect that must be prevented. This multiyear, multicollaborative research effort was carried out to study solvation and self-organization in non-aqueous solutions at conditions promoting aggregation phenomena. Our approach to this challenging topic was to investigate extraction systems comprising more than one extraction reagent where synergy of the metal ion could be observed. These systems were probed for the existence of stable microemulsions in the organic phase, and a number of high-end characterization tools were employed to elucidate the role of the aggregates in metal ion extraction. The ultimate goal was to find connections between synergy of metal ion extraction and reverse micellar formation. Our main accomplishment for this project was the expansion of the understanding of metal ion complexation in the extraction system combining tributyl phosphate (TBP) and dibutyl phosphoric acid (HDBP). We have found that for this system no direct correlation exists for the metal ion extraction and the formation of aggregates, meaning that the

  15. [Influence of temperature on spatial fibrin clot formation process in thrombodynamics].

    PubMed

    Shcherbina, I A; Lipets, E N; Abaeva, A A; Balandina, A N; Ataullakhanov, F I

    2014-01-01

    In this study we have investigated the process of spatial fibrin clot formation in non-steered platelet-free plasma at the temperatures from 20°C to 43°C using thrombodynamics - the novel in vitro hemostasis assay, which imitates the process of hemostatic clot growth in vivo. During data processing the following parameters were calculated: initial (V i ) and stationary (V st ) rates of clot growth which characterize initiation and propagation phases of clotting process, and clot size on the 30 th minute. The temperature dependence of extrinsic and intrinsic tenase activities, which determine values of the initial and stationary clot growth rates, respectively, have been also measured. It was established that the temperature lowering from 37°C to 24°C extends mainly on the initiation phase of clot growth, while the stationary rate of clot growth changes insignificantly. Meanwhile none of the thrombodynamics parameters shows the dramatic change of plasma coagulation system condition at the temperature of 24°C (acute hypothermia). Using the thrombodynamics assay an assumption, that the temperature lowering does not change the state of plasma hemostasis system significantly has been confirmed.

  16. Processes of benthic foraminiferal fossil assemblage formation on the continental slope

    SciTech Connect

    Loubere, P. )

    1991-03-01

    Theoretical analysis of benethic foraminiferal fossil assemblage formation shows that the assemblage eventually preserved in the sediments is an integrated result of species' test production rate, microhabitat behavior, and biogeochemical processes that control the probability of species' test preservation. The biogeochemical processes that influence test preservation in slope sediments are controlled by the flux of organic carbon to the sea-bed and the botton water oxygen concentration. These variables also affect the depth of the biotic habitation zone in the sediments. Therefore, organic carbon flux and bottom water oxygen content should be reflected in benthic foraminiferal fossil assemblages for both ecologic and taphonomic reasons. An integrated study of fossil assemblage generation was conducted on the Gulf of Mexico continental slope using box cores collected along depth transects across the oxygen minimum, and using live and dead assemblage analysis combined with {sup 210}Pb measurements to quantify biotic activity in the sediments and pore water nutrient and metals analysis to quantify biogeochemical processes acting in the sediment habitation zone. The results show that the size of the habitation zone and live standing stock are influenced by organic carbon flux and oxygen supply to the sea-bed. The fossil assemblage is created progressively through the upper 10-20 cm of sediment and biologichemically driven test destruction (taphonomic process) is important in determining the assemblage that enters the geologic record.

  17. International Processes of Education Policy Formation: An Analytic Framework and the Case of Plan 2021 in El Salvador

    ERIC Educational Resources Information Center

    Edwards, D. Brent, Jr.

    2013-01-01

    This article uses multiple perspectives to frame international processes of education policy formation and then applies the framework to El Salvador's Plan 2021 between 2003 and 2005. These perspectives are policy attraction, policy negotiation, policy imposition, and policy hybridization. Research reveals that the formation of Plan 2021 was the…

  18. Extension of the sasCIF format and its applications for data processing and deposition

    DOE PAGES

    Kachala, Michael; Westbrook, John; Svergun, Dmitri

    2016-02-01

    Recent advances in small-angle scattering (SAS) experimental facilities and data analysis methods have prompted a dramatic increase in the number of users and of projects conducted, causing an upsurge in the number of objects studied, experimental data available and structural models generated. To organize the data and models and make them accessible to the community, the Task Forces on SAS and hybrid methods for the International Union of Crystallography and the Worldwide Protein Data Bank envisage developing a federated approach to SAS data and model archiving. Within the framework of this approach, the existing databases may exchange information and providemore » independent but synchronized entries to users. At present, ways of exchanging information between the various SAS databases are not established, leading to possible duplication and incompatibility of entries, and limiting the opportunities for data-driven research for SAS users. In this work, a solution is developed to resolve these issues and provide a universal exchange format for the community, based on the use of the widely adopted crystallographic information framework (CIF). The previous version of the sasCIF format, implemented as an extension of the core CIF dictionary, has been available since 2000 to facilitate SAS data exchange between laboratories. The sasCIF format has now been extended to describe comprehensively the necessary experimental information, results and models, including relevant metadata for SAS data analysis and for deposition into a database. Processing tools for these files (sasCIFtools) have been developed, and these are available both as standalone open-source programs and integrated into the SAS Biological Data Bank, allowing the export and import of data entries as sasCIF files. Software modules to save the relevant information directly from beamline data-processing pipelines in sasCIF format are also developed. Lastly, this update of sasCIF and the relevant tools are

  19. Extension of the sasCIF format and its applications for data processing and deposition.

    PubMed

    Kachala, Michael; Westbrook, John; Svergun, Dmitri

    2016-02-01

    Recent advances in small-angle scattering (SAS) experimental facilities and data analysis methods have prompted a dramatic increase in the number of users and of projects conducted, causing an upsurge in the number of objects studied, experimental data available and structural models generated. To organize the data and models and make them accessible to the community, the Task Forces on SAS and hybrid methods for the International Union of Crystallography and the Worldwide Protein Data Bank envisage developing a federated approach to SAS data and model archiving. Within the framework of this approach, the existing databases may exchange information and provide independent but synchronized entries to users. At present, ways of exchanging information between the various SAS databases are not established, leading to possible duplication and incompatibility of entries, and limiting the opportunities for data-driven research for SAS users. In this work, a solution is developed to resolve these issues and provide a universal exchange format for the community, based on the use of the widely adopted crystallographic information framework (CIF). The previous version of the sasCIF format, implemented as an extension of the core CIF dictionary, has been available since 2000 to facilitate SAS data exchange between laboratories. The sasCIF format has now been extended to describe comprehensively the necessary experimental information, results and models, including relevant metadata for SAS data analysis and for deposition into a database. Processing tools for these files (sasCIFtools) have been developed, and these are available both as standalone open-source programs and integrated into the SAS Biological Data Bank, allowing the export and import of data entries as sasCIF files. Software modules to save the relevant information directly from beamline data-processing pipelines in sasCIF format are also developed. This update of sasCIF and the relevant tools are an important

  20. Extension of the sasCIF format and its applications for data processing and deposition

    SciTech Connect

    Kachala, Michael; Westbrook, John; Svergun, Dmitri

    2016-02-01

    Recent advances in small-angle scattering (SAS) experimental facilities and data analysis methods have prompted a dramatic increase in the number of users and of projects conducted, causing an upsurge in the number of objects studied, experimental data available and structural models generated. To organize the data and models and make them accessible to the community, the Task Forces on SAS and hybrid methods for the International Union of Crystallography and the Worldwide Protein Data Bank envisage developing a federated approach to SAS data and model archiving. Within the framework of this approach, the existing databases may exchange information and provide independent but synchronized entries to users. At present, ways of exchanging information between the various SAS databases are not established, leading to possible duplication and incompatibility of entries, and limiting the opportunities for data-driven research for SAS users. In this work, a solution is developed to resolve these issues and provide a universal exchange format for the community, based on the use of the widely adopted crystallographic information framework (CIF). The previous version of the sasCIF format, implemented as an extension of the core CIF dictionary, has been available since 2000 to facilitate SAS data exchange between laboratories. The sasCIF format has now been extended to describe comprehensively the necessary experimental information, results and models, including relevant metadata for SAS data analysis and for deposition into a database. Processing tools for these files (sasCIFtools) have been developed, and these are available both as standalone open-source programs and integrated into the SAS Biological Data Bank, allowing the export and import of data entries as sasCIF files. Software modules to save the relevant information directly from beamline data-processing pipelines in sasCIF format are also developed. Lastly, this update of sasCIF and the

  1. Ion-induced Processing of Cosmic Silicates: A Possible Formation Pathway to GEMS

    NASA Astrophysics Data System (ADS)

    Jäger, C.; Sabri, T.; Wendler, E.; Henning, Th.

    2016-11-01

    Ion-induced processing of dust grains in the interstellar medium and in protoplanetary and planetary disks plays an important role in the entire dust cycle. We have studied the ion-induced processing of amorphous MgFeSiO4 and Mg2SiO4 grains by 10 and 20 keV protons and 90 keV Ar+ ions. The Ar+ ions were used to compare the significance of the light protons with that of heavier, but chemically inert projectiles. The bombardment was performed in a two-beam irradiation chamber for in situ ion-implantation at temperatures of 15 and 300 K and Rutherford Backscattering Spectroscopy to monitor the alteration of the silicate composition under ion irradiation. A depletion of oxygen from the silicate structure by selective sputtering of oxygen from the surface of the grains was observed in both samples. The silicate particles kept their amorphous structure, but the loss of oxygen caused the reduction of ferrous (Fe2+) ions and the formation of iron inclusions in the MgFeSiO4 grains. A few Si inclusions were produced in the iron-free magnesium silicate sample pointing to a much less efficient reduction of Si4+ and formation of metallic Si inclusions. Consequently, ion-induced processing of magnesium-iron silicates can produce grains that are very similar to the glassy grains with embedded metals and sulfides frequently observed in interplanetary dust particles and meteorites. The metallic iron inclusions are strong absorbers in the NIR range and therefore a ubiquitous requirement to increase the temperature of silicate dust grains in IR-dominated astrophysical environments such as circumstellar shells or protoplanetary disks.

  2. Modern Limnology and Varve Formation Processes in Lake Montcortès (Southern Pyrenees, Spain)

    NASA Astrophysics Data System (ADS)

    Trapote forné, M.; López, P.; Puche, E.; Safont, E.; Cañellas-Boltà, N.; Gomà, J.; Buchaca, T.; Pérez-Zanón, N.; Sigró, J.; Rull, V.; Vegas-Vilarrúbia, T.

    2015-12-01

    Lake Montcortès is a karstic lake located in Catalonian Pyrenees (Spain). Its sediments consist of biogenic varves composed of a couplet of calcite and organic matter layers and occasional detrital layer. Previous studies of the lake's sediments spanning the last 1500 years proposed that the lake was meromictic and that calcite layers formed due to endogenic precipitation in the epilimnion during spring/summer, driven by diatom blooms. These processes would have been influenced by variations in calcium saturation, trophic state and water temperature of the lake. The presence of phosphorous and biological differences between planktonic diatoms Cyclotella comta and C.cyclopuncta, would have produced additional differences in calcite sublayering. In order to improve comprehension of limnological variables that influence varve formation processes, monthly field campaigns including sediment traps deployment have been carried out during two concurrent years (2013-2015). The lake mixed once during winter. Endogenic calcite precipitation related with high primary production and calcium saturation in metalimnetic water was confirmed. Trapped material composition revealed low but constant calcite precipitation through the year with higher intensities during summer and autumn, coinciding with high relative abundances of C. cyclopuncta and C.ocellata. Nutrient content was very low throughout both years, particularly phosphorous. It seems to be removed by coprecipitation of calcium phosphate with calcite during summer, probably inhibiting part of calcite precipitation reaction. In contrast to previous hypotheses, currently calcite precipitation occurs through the whole year, mainly during summer and autumn months, and may be triggered by nucleation with picoplankton. Our study shows that processes leading to varve formation are highly complex and that any extrapolation to different regions or time periods should be handled with caution

  3. A low-energy chilled ammonia process exploiting controlled solid formation for post-combustion CO2 capture.

    PubMed

    Sutter, Daniel; Gazzani, Matteo; Mazzotti, Marco

    2016-10-20

    A new ammonia-based process for CO2 capture from flue gas has been developed, which utilizes the formation of solid ammonium bicarbonate to increase the CO2 concentration in the regeneration section of the process. Precipitation, separation, and dissolution of the solid phase are realized in a dedicated process section, while the packed absorption and desorption columns remain free of solids. Additionally, the CO2 wash section applies solid formation to enable a reduction of the wash water consumption. A rigorous performance assessment employing the SPECCA index (Specific Primary Energy Consumption for CO2 Avoided) has been implemented to allow for a comparison of the overall energy penalty between the new process and a standard ammonia-based capture process without solid formation. A thorough understanding of the relevant solid-solid-liquid-vapor phase equilibria and an accurate modeling of them have enabled the synthesis of the process, and have inspired the development of the optimization algorithm used to screen a wide range of operating conditions in equilibrium-based process simulations. Under the assumptions on which the analysis is based, the new process with controlled solid formation achieved a SPECCA of 2.43 MJ kgCO2(-1), corresponding to a reduction of 17% compared to the process without solid formation (with a SPECCA of 2.93 MJ kgCO2(-1)). Ways forward to confirm this significant improvement, and to increase the accuracy of the optimization are also discussed.

  4. Deciphering Transcriptional Programming during Pod and Seed Development Using RNA-Seq in Pigeonpea (Cajanus cajan)

    PubMed Central

    Pazhamala, Lekha T.; Agarwal, Gaurav; Bajaj, Prasad; Kumar, Vinay; Kulshreshtha, Akanksha; Saxena, Rachit K.; Varshney, Rajeev K.

    2016-01-01

    Seed development is an important event in plant life cycle that has interested humankind since ages, especially in crops of economic importance. Pigeonpea is an important grain legume of the semi-arid tropics, used mainly for its protein rich seeds. In order to understand the transcriptional programming during the pod and seed development, RNA-seq data was generated from embryo sac from the day of anthesis (0 DAA), seed and pod wall (5, 10, 20 and 30 DAA) of pigeonpea variety “Asha” (ICPL 87119) using Illumina HiSeq 2500. About 684 million sequencing reads have been generated from nine samples, which resulted in the identification of 27,441 expressed genes after sequence analysis. These genes have been studied for their differentially expression, co-expression, temporal and spatial gene expression. We have also used the RNA-seq data to identify important seed-specific transcription factors, biological processes and associated pathways during seed development process in pigeonpea. The comprehensive gene expression study from flowering to mature pod development in pigeonpea would be crucial in identifying candidate genes involved in seed traits directly or indirectly related to yield and quality. The dataset will serve as an important resource for gene discovery and deciphering the molecular mechanisms underlying various seed related traits. PMID:27760186

  5. DeGNServer: deciphering genome-scale gene networks through high performance reverse engineering analysis.

    PubMed

    Li, Jun; Wei, Hairong; Zhao, Patrick Xuechun

    2013-01-01

    Analysis of genome-scale gene networks (GNs) using large-scale gene expression data provides unprecedented opportunities to uncover gene interactions and regulatory networks involved in various biological processes and developmental programs, leading to accelerated discovery of novel knowledge of various biological processes, pathways and systems. The widely used context likelihood of relatedness (CLR) method based on the mutual information (MI) for scoring the similarity of gene pairs is one of the accurate methods currently available for inferring GNs. However, the MI-based reverse engineering method can achieve satisfactory performance only when sample size exceeds one hundred. This in turn limits their applications for GN construction from expression data set with small sample size. We developed a high performance web server, DeGNServer, to reverse engineering and decipher genome-scale networks. It extended the CLR method by integration of different correlation methods that are suitable for analyzing data sets ranging from moderate to large scale such as expression profiles with tens to hundreds of microarray hybridizations, and implemented all analysis algorithms using parallel computing techniques to infer gene-gene association at extraordinary speed. In addition, we integrated the SNBuilder and GeNa algorithms for subnetwork extraction and functional module discovery. DeGNServer is publicly and freely available online.

  6. Hydrologic Connectivity as a Window into Pattern Conditions and Formation Processes in Aquatic Ecosystems

    NASA Astrophysics Data System (ADS)

    Larsen, L. G.; Choi, J.; Nungesser, M. K.; Harvey, J. W.

    2011-12-01

    Patterned aquatic ecosystems exhibit different types and degrees of hydrologic connectivity, from isolated open-water patches in some inland marshes, to cross-slope strings and flarks of striped fens, to along-slope ridges and sloughs of low-gradient subtropical wetlands, to dendritic channels of coastal marshes. The nature and degree of this connectivity are closely linked to landscape function. For example, hydrologic connectivity perpendicular to river channel thalwegs relates to the exchange of sediment and nutrients between channels and floodplains, whereas connectivity parallel to a dominant flow direction affects fish migration or the likelihood of contaminant transport. Characteristics of hydrologic connectivity reflect not only the results of landscape pattern but also the mechanisms responsible for pattern creation. Quantifying those connectivity characteristics provides a robust means to identify landscapes likely formed under a consistent set of processes or to compare the output of landscape simulation models to actual landscapes in order to determine whether the models capture the most relevant landscape formation processes. However, established methods for quantifying isotropic patch connectivity are often ill suited for strongly patterned landscapes or hydroscapes in which directional flow is important. Using graph theory principles, we developed two alternative indices of directional hydrologic connectivity: the maximum flow index (MFI) and directional connectivity index (DCI), which quantify the connectivity of flow paths along a particular axis of interest. The MFI is sensitive to the existence of any hydrologic connection along the direction of interest, whereas the DCI is sensitive to the linearity of connections along that direction. Curves of directional connectivity over a range of angular bearings provide a quantitative, information-dense representation of landscape structure that can be related to subtle differences in the physical

  7. Formation and Destruction Processes of Interstellar Dust: From Organic Molecules to carbonaceous Grains

    NASA Technical Reports Server (NTRS)

    Salama, F.; Biennier, L.

    2004-01-01

    The study of the formation and destruction processes of cosmic dust is essential to understand and to quantify the budget of extraterrestrial organic molecules. interstellar dust presents a continuous size distribution from large molecules, radicals and ions to nanometer-sized particles to micron-sized grains. The lower end of the dust size distribution is thought to be responsible for the ubiquitous spectral features that are seen in emission in the IR (UIBs) and in absorption in the visible (DIBs). The higher end of the dust-size distribution is thought to be responsible for the continuum emission plateau that is seen in the IR and for the strong absorption seen in the interstellar UV extinction curve. All these spectral signatures are characteristic of cosmic organic materials that are ubiquitous and present in various forms from gas-phase molecules to solid-state grains. Although dust with all its components plays an important role in the evolution of interstellar chemistry and in the formation of organic molecules, little is known on the formation and destruction processes of dust. Recent space observations in the UV (HST) and in the IR (ISO) help place size constraints on the molecular component of carbonaceous IS dust and indicate that small (ie., subnanometer) PAHs cannot contribute significantly to the IS features in the UV and in the IR. Studies of large molecular and nano-sized IS dust analogs formed from PAH precursors have been performed in our laboratory under conditions that simulate diffuse ISM environments (the particles are cold -100 K vibrational energy, isolated in the gas phase and exposed to a high-energy discharge environment in a cold plasma). The species (molecules, molecular fragments, ions, nanoparticles, etc) formed in the pulsed discharge nozzle (PDN) plasma source are detected with a high-sensitivity cavity ring-down spectrometer (CRDS). We will present new experimental results that indicate that nanoparticles are generated in the

  8. Deciphering the Transitional Tectonics of the Southern Alaska Margin Through Gulf Sedimentology and Geophysics: IODP Expedition 341

    NASA Astrophysics Data System (ADS)

    Reece, R.; Gulick, S. P. S.; Jaeger, J. M.

    2014-12-01

    Southern Alaska is a complex amalgam of tectonic environments, centered on the subduction/collision of the Yakutat Block with North America. Along the Aleutians in the west, the Pacific Plate subducts normally beneath North America, with a gradually shallowing subduction angle towards the Yakutat Terrane to the east. The western region of the Yakutat Block undergoes nearly flat-slab subduction beneath North America, whereas it transitions to collision in the northeast, which is the primary driver for the growth of the Chugach-St. Elias orogen. Farther to the east, the collisional system transitions to a transform boundary with the Fairweather-Queen Charlotte fault system. The collisional system contributes to farfield tectonic effects in many regions, including northern Alaska and the Pacific Plate, but also combines with glaciation to drive sedimentation in the Gulf of Alaska. Glaciation has periodically increased in the St. Elias Range since the Miocene, but began dominating erosion and spurred enhanced exhumation since the intensification of Northern Hemisphere glaciation, at ~2.5 Ma. Results from IODP Expedition 341 show the first appearance of ice-rafted debris and a doubling of Gulf sedimentation at site U1417 at this age, and a major increase in sedimentation at ~1 Ma at sites U1417 and U1418. Glacigenic sediment flux into the Gulf of Alaska represents the majority of accumulation in the deepwater Surveyor Fan, and was the impetus for formation of the Surveyor Channel system. Climate events correlate to three major differentiable sequences across the Surveyor Fan that have been previously mapped using seismic reflection profiles. The change in morphology observed throughout the sequences allows us to characterize the influence that a glaciated orogen can have in shaping margin processes and the sediment pathways from source to sink. IODP Expedition 341 results allow us to now apply this method at higher resolution time scales (i.e., 100 kyr). We will explore

  9. The process of ghost-rock karstification and its role in the formation of cave systems

    NASA Astrophysics Data System (ADS)

    Dubois, C.; Quinif, Y.; Baele, J.-M.; Barriquand, L.; Bini, A.; Bruxelles, L.; Dandurand, G.; Havron, C.; Kaufmann, O.; Lans, B.; Maire, R.; Martin, J.; Rodet, J.; Rowberry, M. D.; Tognini, P.; Vergari, A.

    2014-04-01

    This paper presents an extensive review of the process of ghost-rock karstification and highlights its role in the formation of cave systems. The process integrates chemical weathering and mechanical erosion and extends a number of existing theories pertaining to continental landscape development. It is a two stage process that differs in many respects from the traditional single-stage process of karstification by total removal. The first stage is characterised by chemical dissolution and removal of the soluble species. It requires low hydrodynamic energy and creates a ghost-rock feature filled with residual alterite. The second stage is characterised by mechanical erosion of the undissolved particles. It requires high hydrodynamic energy and it is only then that open galleries are created. The transition from the first stage to the second is driven by the amount of energy within the thermodynamic system. The process is illustrated by detailed field observations and the results of the laboratory analyses of samples taken from the karstotype area around Soignies in southern Belgium. Thereafter, a series of case studies provide a synthesis of field observations and laboratory analyses from across western Europe. These studies come from geologically distinct parts of Belgium, France, Italy, and the United Kingdom. The process of ghost-rock karstification challenges a number of axioms associated with the process of karstification by total removal. On the basis of the evidence presented it is argued that it is no longer acceptable to use karst morphologies as a basis with which to infer specific karstogenetic processes and it is no longer necessary for a karst system to relate to base level as ghost-rock karstification proceeds along transmissive pathways in the rock. There is also some evidence to suggest that ghost-rock karstification may be superseded by karstification by total removal, and vice versa, according to the amount of energy within the thermodynamic system

  10. Control of Listeria monocytogenes in the processing environment by understanding biofilm formation and resistance to sanitizers.

    PubMed

    Manios, Stavros G; Skandamis, Panagiotis N

    2014-01-01

    Listeria monocytogenes can colonize in the food processing environment and thus pose a greater risk of cross-contamination to food. One of the proposed mechanisms that facilitates such colonization is biofilm formation. As part of a biofilm, it is hypothesized that L. monocytogenes can survive sanitization procedures. In addition, biofilms are difficult to remove and may require additional physical and chemical mechanisms to reduce their presence and occurrence. The initial stage of biofilm formation is attachment to surfaces, and therefore it is important to be able to determine the ability of L. monocytogenes strains to attach to various inert surfaces. In this chapter, methods to study bacterial attachment to surfaces are described. Attachment is commonly induced by bringing planktonic cells into contact with plastic, glass, or stainless steel surfaces with or without food residues ("soil") in batch or continuous (e.g., with constant flow of nutrients) culture. Measurement of biofilm formed is carried out by detaching cells (with various mechanical methods) and measuring the viable counts or by measuring the total attached biomass. Resistance of biofilms to sanitizers is commonly carried out by exposure of the whole model surface bearing the attached cells to a solution of sanitizer, followed by measuring the survivors as described above.

  11. Empirical analysis of the lane formation process in bidirectional pedestrian flow

    NASA Astrophysics Data System (ADS)

    Feliciani, Claudio; Nishinari, Katsuhiro

    2016-09-01

    This paper presents an experimental study on pedestrian bidirectional streams and the mechanisms leading to spontaneous lane formation by examining the flow formed by two groups of people walking toward each other in a mock corridor. Flow ratio is changed by changing each group size while maintaining comparable total flow and density. By tracking the trajectories of each pedestrian and analyzing the data obtained, five different phases were recognized as contributing to the transition from unidirectional to bidirectional flow including the spontaneous creation and dissolution of lanes. It has been shown that a statistical treatment is required to understand the fundamental characteristics of pedestrian dynamics and some two-dimensional quantities such as order parameter and rotation range were introduced to allow a more complete analysis. All the quantities observed showed a clear relationship with flow ratio and helped distinguishing between the different characteristic phases of the experiment. Results show that balanced bidirectional flow becomes the most stable configuration after lanes are formed, but the lane creation process requires pedestrians to laterally move to a largest extent compared to low flow-ratio configurations. This finding allows us to understand the reasons why balanced bidirectional flow is efficient at low densities, but quickly leads to deadlock formation at high densities.

  12. CONSTRAINTS ON FEEDBACK PROCESSES DURING THE FORMATION OF EARLY-TYPE GALAXIES

    SciTech Connect

    Trevisan, M.; De La Rosa, I. G.; La Barbera, F.; De Carvalho, R. R.

    2012-06-20

    Galaxies are found to obey scaling relations between a number of observables. These relations follow different trends at the low- and high-mass ends. The processes driving the curvature of scaling relations remain uncertain. In this Letter, we focus on the specific family of early-type galaxies, deriving the star formation histories of a complete sample of visually classified galaxies from Sloan Digital Sky Survey DR7 over the redshift range 0.01 < z < 0.025, covering a stellar mass interval from 10{sup 9} to 3 Multiplication-Sign 10{sup 11} M{sub Sun }. Our sample features the characteristic 'knee' in the surface brightness versus mass distribution at M{sub *} {approx} 3 Multiplication-Sign 10{sup 10} M{sub Sun} . We find a clear difference between the age and metallicity distributions of the stellar populations above and beyond this knee, which suggests a sudden transition from a constant, highly efficient mode of star formation in high-mass galaxies, gradually decreasing toward the low-mass end of the sample. At fixed mass, our early-type sample is more efficient in building up the stellar content at early times in comparison to the general population of galaxies, with half of the stars already in place by redshift z {approx} 2 for all masses. The metallicity-age trend in low-mass galaxies is not compatible with infall of metal-poor gas, suggesting instead an outflow-driven relation.

  13. Laticiferous canal formation in fruits of Decaisnea fargesii: a programmed cell death process?

    PubMed

    Zhou, Ya-Fu; Liu, Wen-Zhe

    2011-10-01

    Programmed cell death (PCD), a topic of abiding interest, remodels plants at the cell, tissue, and organ levels involving various developmental processes of plants. The aim of this study is to provide a morphological characterization of evidence of PCD involvement in the laticiferous canal formation in fruit of Decaisnea fargesii. Several ultrastructural features of PCD have been observed including disintegration of vacuole and plasma membranes, cell wall degeneration, degenerated cytoplasm, abundant membrane structures and flocculent material, mitochondria and misshapen nuclei coupled with degraded plastids in vacuoles, and nuclei enveloped by rubber granule. In D. fargesii, the nuclei of the secretory epidermal cells become TUNEL-positive from the sunken stage to the late expanding stage, then DAPI-negative during the mature stage, indicating an early event of deoxyribonucleic acid (DNA) cleavage and a late event of complete DNA degeneration. Gel electrophoresis indicates that DNA cleavage is random and does not result in the laddering pattern indicating multiples of internucleosomal units. During the PCD of secretory epidermal cells, the rubber granules continue to be synthesized and accumulated in the secretory epidermal cells despite nuclear degradation. The PCD's role in laticiferous canal formation suggests that PCD may play important roles in gland development of plants.

  14. Formation of extracellular polymeric substances from acidogenic sludge in H2-producing process.

    PubMed

    Sheng, Guo-Ping; Yu, Han-Qing

    2007-02-01

    In this study, the formation of extracellular polymeric substances (EPS) and surface characteristics of an acidogenic sludge in anaerobic H(2)-producing process was investigated. Results show that carbohydrates, proteins, and humic substances were the dominant components in bound EPS (BEPS), while in soluble EPS (SEPS), carbohydrates were the main component. The total content of BEPS initially increased but then kept almost unchanged during fermentation from 25 to 35 h; after that, it slightly decreased. The total content of SEPS increased to 172.5 +/- 0.05 mg C g(-1) volatile suspended solid with the time that increased to 23.5 h, and then rapidly decreased until 43 h; thereafter, it kept almost unchanged. The SEPS had good correlations with the specific H(2) production rate, substrate degradation rate, and specific aqueous products formation rate, but the BEPS seemed to have no such correlations with these specific rates. Results also confirm that part of EPS could be utilized by the H(2)-producing sludge. As the substrate was in short supply, the EPS would be hydrolyzed to sever as carbon and energy source.

  15. Polymer-melt interactions during casting formation in the lost foam process

    SciTech Connect

    Shivkumar, S.; Yao, X.; Makhlouf, M.

    1995-07-01

    The lost foam casting process utilizes injection modeled polymeric foam patterns for the production of metallic components. Foamed polymer patterns of the desired shape are coated with a water-based refractory slurry, dried and embedded in unbonded sand. Molten metal is poured directly on the coated polymer. The polymer undergoes thermal degradation and is gradually replaced by the liquid metal to yield the casting after solidification. Expanded polystyrene (EPS) is the most common pattern material used in commercial practice. The use of EPS patterns with ferrous castings may result in the formation of carbonaceous defects in the casting. Consequently, polymethylmethacrylate (PMMA) and copolymers of EPS and PMMA have been developed for ferrous castings. The thermal degradation of the foamed pattern results in the formation of gaseous degradation products and of a partially depolymerized viscous residue. The fraction of viscous residue increased with temperature and is essentially constant above about 650 C. During the filling of EPS patterns, nearly 60% of the polymer is converted to the viscous residue and 40% is transformed to gaseous products. In the case of PMM, almost 60% of the polymer undergoing degradation at the metal front is transformed to gaseous products. The melt flow velocity during the filling of the mold generally increases with temperature.

  16. Ionic liquid effects on a multistep process. Increased product formation due to enhancement of all steps.

    PubMed

    Keaveney, Sinead T; Haines, Ronald S; Harper, Jason B

    2015-09-07

    The reaction of a series of substituted benzaldehydes with hexylamine was examined in acetonitrile and an ionic liquid. In acetonitrile, as the electron withdrawing nature of the substituent increases, the overall addition-elimination process becomes faster as does the build-up of the aminol intermediate. Under equivalent conditions in an ionic liquid, less intermediate build up is observed, and the effect on the rate on varying the substituent is different to that in acetonitrile. Extensive kinetic analysis shows that the ionic liquid solvent increases the rate constant of all steps of the reaction, resulting in faster product formation relative to acetonitrile; these effects increase with the proportion of ionic liquid in the reaction mixture. Differences in the equilibrium position of the addition step in the ionic liquid were found to account for both the decrease in intermediate build up relative to acetonitrile, as well as the differing trend in the overall rate of product formation as the substituent was changed. The microscopic origins of these ionic liquid effects were probed through temperature dependent analyses, highlighting the subtle balance of interactions between the ionic liquid and species along the reaction coordinate, particularly the importance of charge development in the transition state.

  17. Control of disinfection by-product formation using ozone-based advanced oxidation processes.

    PubMed

    Chen, Kuan-Chung; Wang, Yu-Hsiang

    2012-01-01

    The effects of ozone dosage, water temperature and catalyst addition in an ozonation-fluidized bed reactor (O3/FBR) on treated water quality and on the control of chlorinated and ozonated disinfection by-products (DBPs) were investigated. A biofiltration column was used to evaluate its removal efficiency on biodegradable organic matter and to reduce DBP formation. The Dong-Gang River, polluted by agricultural and domestic wastewater in Pingtung, Taiwan, was used as the water source. The treated water quality in terms of dissolved organic carbon (DOC), biodegradable DOC, ultraviolet absorbance at 254 nm (UV254) and specific UV absorbance (SUVA) improved with increasing ozone and catalyst dosages. Catalytic ozonation was more effective than ozonation alone at reducing the formation of DBPs at a given dosage. Experimental results show that water temperature had little effect on the treated water quality with the O3/FBR system used in this study (p > 0.05). The combination of O3/FBR and the biofiltration process effectively decreased the amount ofDBP precursors. The concentration of total trihalomethanes (TTHMs) was less than the maximum contaminant level (MCL) requirement, which is 80 microg/L, for all treated waters and the concentration of five haloacetic acids (HAA5) fell below 60 microg/L with an ozone dosage higher than 2.5 mg/L.

  18. Hall effect on a Merging Formation Process of a Field-Reversed Configuration

    NASA Astrophysics Data System (ADS)

    Kaminou, Yasuhiro; Guo, Xuehan; Inomoto, Michiaki; Ono, Yasushi; Horiuchi, Ritoku

    2015-11-01

    Counter-helicity spheromak merging is one of the formation methods of a Field-Reversed Configuration (FRC). In counter-helicity spheromak merging, two spheromaks with opposing toroidal fields merge together, through magnetic reconnection events and relax into a FRC, which has no or little toroidal field. This process contains magnetic reconnection and a relaxation phenomena, and the Hall effect has some essential effects on these process because the X-point in the magnetic reconnection or the O-point of the FRC has no or little magnetic field. However, the Hall effect as both global and local effect on counter-helicity spheromak merging has not been elucidated. In this poster, we conducted 2D/3D Hall-MHD simulations and experiments of counter-helicity spheromak merging. We find that the Hall effect enhances the reconnection rate, and reduces the generation of toroidal sheared-flow. The suppression of the ``slingshot effect'' affects the relaxation process. We will discuss details in the poster.

  19. Teachers and the religious socialization of adolescents: facilitation of meaningful religious identity formation processes.

    PubMed

    Cohen-Malayev, Maya; Schachter, Elli P; Rich, Yisrael

    2014-02-01

    This study investigated the effects of religious education on student religious identity over and above parent religiosity by examining student perceptions of two aspects of teacher functioning: teacher caring and teacher as role-model. We posited that effects of these variables on students' religious identity are mediated by student perceptions that the school provides a non-alienating religious atmosphere and meaningful religious studies. Participants were 2691 male and female students (grades 9-12) in 152 classes of 25 schools from the Jewish public-religious sector in Israel. Results indicate that in addition to their parents' religiosity, adolescents' perceptions of their teachers as role models and their religious studies as meaningful are important variables affecting their religious identity. Moreover, this research suggests that religious identity formation processes flourish in an educational environment which students perceive as accommodating religious exploration.

  20. The characteristics and processes of NO{sub x} formation/destruction in staged combustion

    SciTech Connect

    Xu, Zhe; Hayashi, Shigeru; Takagi, Toshimi

    1999-07-01

    The characteristics and processes of NO formation and destruction in methane-air staged combustion taking place in the re-burning technique were studied numerically by using detailed chemical kinetics compiled by GRL Special attention was paid to the effects of equivalence ratio, temperature and pressure. The model of staged combustion used in the computation consists of three stages: firstly well-stirred reactor, and then two one-dimensional plug flows, one with a secondary fuel inlet, the other a secondary air inlet. It is assumed that the secondary fuel is injected instantaneously at the inlet of the second stage, and the secondary air is injected over a certain time along the flow in the third stage. After their injection, secondary fuel and air are rapidly mixed with the primary combustion gas which comes from the previous stage. The results are described.

  1. Formation process of a strong water-repellent alumina surface by the sol-gel method

    NASA Astrophysics Data System (ADS)

    Feng, Libang; Li, Hui; Song, Yongfeng; Wang, Yulong

    2010-03-01

    A novel strong water-repellent alumina thin film is fabricated by chemically adsorbing stearic acid (STA) layer onto the porous and roughened aluminum film coated with polyethyleneimine (PEI). The formation process and the structure of the strong water-repellent alumina film are investigated by means of contact angle measurement and atomic force microscope (AFM). Results show that the water contact angles for the alumina films increase with the increase of the immersion time in the boiling water, and meanwhile, the roughness of the alumina films increases with the dissolution of the boehmite in the boiling water. Finally, the strong water-repellent film with a high water contact angle of 139.1° is obtained when the alumina films have distinct roughened morphology with some papillary peaks and porous structure. Moreover, both the roughened structure and the hydrophobic materials of the STA endow the alumina films with the strong water-repellence.

  2. Monitoring process of human keloid formation based on second harmonic generation imaging

    NASA Astrophysics Data System (ADS)

    Jiang, X. S.; Chen, S.; Chen, J. X.; Zhu, X. Q.; Zheng, L. Q.; Zhuo, S. M.; Wang, D. J.

    2011-09-01

    In this paper, the morphological variation of collagen among the whole dermis from keloid tissue was investigated using second harmonic generation (SHG) microscopy. In the deep dermis of keloids, collagen bundles show apparently regular gap. In the middle dermis, the collagen bundles are randomly oriented and loosely arranged in the pattern of fine mesh while the collagen bundles are organized in a parallel manner in the superficial dermis near the epidermis. The developed parameters COI and BD can be used to further quantitatively describe these changes. Our results demonstrate the potential of SHG microscopy to understand the formation process of human keloid scar at the cellular level through imaging collagen variations in different depth of dermis.

  3. Experimental and Computational Analysis of Water-Droplet Formation and Ejection Process Using Hollow Microneedle

    NASA Astrophysics Data System (ADS)

    Kato, Norihisa; Oka, Ryotaro; Sakai, Takahiro; Shibata, Takayuki; Kawashima, Takahiro; Nagai, Moeto; Mineta, Takashi; Makino, Eiji

    2011-06-01

    In this paper, we present the possibility of liquid delivery using fabricated hollow silicon dioxide microneedles of approximately 2 µm in diameter. As a fundamental study, the water-droplet formation and ejection process was examined via dynamic observations during water ejection tests and computational fluid dynamics (CFD) analysis. The experimental results indicated that fluid flow in a microneedle follows the Hagen-Poiseuille law, i.e., the flow rate is approximately directly proportional to the fourth power of the inner diameter. Moreover, the ejection pressure and maximum droplet curvature obtained using the proposed microfluid ejection model were in good agreement with the experimental results. The resulting ejection pressure is equal to the theoretical pressure difference of a spherical droplet, which is determined using the Young-Laplace equation. The maximum curvature of a droplet formed at the tip of a microneedle can be estimated on the basis of the contact angle theory expressed by the Young equation.

  4. [Functional asymmetry of electric processes in the rabbit brain cortex at formation of the hunger dominant].

    PubMed

    Rusinova, E V

    2011-01-01

    The motivational condition of hunger and formation of the hunger dominant after daily food deprivation was studied in the conditions of chronic experiments on rabbits. It was shown, that the hunger condition was accompanied by left sided interhemispher asymmetry on indicators of spectral capacity of EEG frontal and right-hand asymmetry sensorimotor areas of the cortex. A hunger dominant was accompanied by falling of spectral capacity of EEG of areas of both hemispheres. The condition of hunger and a hunger dominant were characterized by right-hand asymmetry on average level of EEG coherence of frontal and sensorimotor areas. At transition of a condition of hunger in a hunger dominant there was an average level of EEG coherence decrease in areas of the right hemisphere. Electric processes of the cortex of the brain at a motivational condition of hunger and a hunger dominant were different.

  5. Synthesis and formation mechanism of pinnoite by the phase transition process

    NASA Astrophysics Data System (ADS)

    Lin, Feng; Dong, Yaping; Peng, Jiaoyu; Wang, Liping; Li, Wu

    2016-06-01

    Pinnoite (MgB2O(OH)6) for the first time was synthesized using the solid-liquid-solid conversion method. The effects of reaction time, pH value and concentrations of magnesium and borate were investigated. Pinnoite was synthesized under the optimum condition of 8 mmol hungtsaoite and 1% boric acid solution at 80 °C. The products were determined using X-ray diffraction, Fourier-transform infrared spectroscopy, TG-DSC and a UV-vis spectrometer. The change processes of the surface morphology of pinnoite were investigated using scanning electron microscopy. In addition, the formation mechanism of pinnoite was discussed according to the changes in the content of precipitation and pH value.

  6. Learning processes in the professional development of mental health counselors: knowledge restructuring and illness script formation.

    PubMed

    Strasser, Josef; Gruber, Hans

    2015-05-01

    An important part of learning processes in the professional development of counselors is the integration of declarative knowledge and professional experience. It was investigated in-how-far mental health counselors at different levels of expertise (experts, intermediates, novices) differ in their availability of experience-based knowledge structures. Participants were prompted with 20 client problems. They had to explain those problems, the explanations were analyzed using think-aloud protocols. The results show that experts' knowledge is organized in script-like structures that integrate declarative knowledge and professional experience and help experts in accessing relevant information about cases. Novices revealed less integrated knowledge structures. It is concluded that knowledge restructuring and illness script formation are crucial parts of the professional learning of counselors.

  7. Functional metagenomics to decipher food-microbe-host crosstalk.

    PubMed

    Larraufie, Pierre; de Wouters, Tomas; Potocki-Veronese, Gabrielle; Blottière, Hervé M; Doré, Joël

    2015-02-01

    The recent developments of metagenomics permit an extremely high-resolution molecular scan of the intestinal microbiota giving new insights and opening perspectives for clinical applications. Beyond the unprecedented vision of the intestinal microbiota given by large-scale quantitative metagenomics studies, such as the EU MetaHIT project, functional metagenomics tools allow the exploration of fine interactions between food constituents, microbiota and host, leading to the identification of signals and intimate mechanisms of crosstalk, especially between bacteria and human cells. Cloning of large genome fragments, either from complex intestinal communities or from selected bacteria, allows the screening of these biological resources for bioactivity towards complex plant polymers or functional food such as prebiotics. This permitted identification of novel carbohydrate-active enzyme families involved in dietary fibre and host glycan breakdown, and highlighted unsuspected bacterial players at the top of the intestinal microbial food chain. Similarly, exposure of fractions from genomic and metagenomic clones onto human cells engineered with reporter systems to track modulation of immune response, cell proliferation or cell metabolism has allowed the identification of bioactive clones modulating key cell signalling pathways or the induction of specific genes. This opens the possibility to decipher mechanisms by which commensal bacteria or candidate probiotics can modulate the activity of cells in the intestinal epithelium or even in distal organs such as the liver, adipose tissue or the brain. Hence, in spite of our inability to culture many of the dominant microbes of the human intestine, functional metagenomics open a new window for the exploration of food-microbe-host crosstalk.

  8. Sequential Logic Model Deciphers Dynamic Transcriptional Control of Gene Expressions

    PubMed Central

    Yeo, Zhen Xuan; Wong, Sum Thai; Arjunan, Satya Nanda Vel; Piras, Vincent; Tomita, Masaru; Selvarajoo, Kumar; Giuliani, Alessandro; Tsuchiya, Masa

    2007-01-01

    Background Cellular signaling involves a sequence of events from ligand binding to membrane receptors through transcription factors activation and the induction of mRNA expression. The transcriptional-regulatory system plays a pivotal role in the control of gene expression. A novel computational approach to the study of gene regulation circuits is presented here. Methodology Based on the concept of finite state machine, which provides a discrete view of gene regulation, a novel sequential logic model (SLM) is developed to decipher control mechanisms of dynamic transcriptional regulation of gene expressions. The SLM technique is also used to systematically analyze the dynamic function of transcriptional inputs, the dependency and cooperativity, such as synergy effect, among the binding sites with respect to when, how much and how fast the gene of interest is expressed. Principal Findings SLM is verified by a set of well studied expression data on endo16 of Strongylocentrotus purpuratus (sea urchin) during the embryonic midgut development. A dynamic regulatory mechanism for endo16 expression controlled by three binding sites, UI, R and Otx is identified and demonstrated to be consistent with experimental findings. Furthermore, we show that during transition from specification to differentiation in wild type endo16 expression profile, SLM reveals three binary activities are not sufficient to explain the transcriptional regulation of endo16 expression and additional activities of binding sites are required. Further analyses suggest detailed mechanism of R switch activity where indirect dependency occurs in between UI activity and R switch during specification to differentiation stage. Conclusions/Significance The sequential logic formalism allows for a simplification of regulation network dynamics going from a continuous to a discrete representation of gene activation in time. In effect our SLM is non-parametric and model-independent, yet providing rich biological

  9. Cosmochemical evidence for astrophysical processes during the formation of our solar system.

    PubMed

    MacPherson, Glenn J; Boss, Alan

    2011-11-29

    Through the laboratory study of ancient solar system materials such as meteorites and comet dust, we can recognize evidence for the same star-formation processes in our own solar system as those that we can observe now through telescopes in nearby star-forming regions. High temperature grains formed in the innermost region of the solar system ended up much farther out in the solar system, not only the asteroid belt but even in the comet accretion region, suggesting a huge and efficient process of mass transport. Bi-polar outflows, turbulent diffusion, and marginal gravitational instability are the likely mechanisms for this transport. The presence of short-lived radionuclides in the early solar system, especially (60)Fe, (26)Al, and (41)Ca, requires a nearby supernova shortly before our solar system was formed, suggesting that the Sun was formed in a massive star-forming region similar to Orion or Carina. Solar system formation may have been "triggered" by ionizing radiation originating from massive O and B stars at the center of an expanding HII bubble, one of which may have later provided the supernova source for the short-lived radionuclides. Alternatively, a supernova shock wave may have simultaneously triggered the collapse and injected the short-lived radionuclides. Because the Sun formed in a region where many other stars were forming more or less contemporaneously, the bi-polar outflows from all such stars enriched the local region in interstellar silicate and oxide dust. This may explain several observed anomalies in the meteorite record: a near absence of detectable (no extreme isotopic properties) presolar silicate grains and a dichotomy in the isotope record between (26)Al and nucleosynthetic (nonradiogenic) anomalies.

  10. Bubble Formation and Transport during Microgravity Materials Processing: Model Experiments on the International Space Station

    NASA Technical Reports Server (NTRS)

    Grugel, R. N.; Anilkumar, A. V.; Lee, C. P.

    2003-01-01

    Flow Visualization experiments on the controlled melting and solidification of succinonitrile were conducted in the glovebox facility of the International Space Station (ISS). The experimental samples were prepared on ground by filling glass tubes, 1 cm ID and approximately 30 cm in length, with pure succinonitrile (SCN) under 450 millibar of nitrogen. Porosity in the samples arose from natural shrinkage, and in some cases by direct insertion of nitrogen bubbles, during solidification of the liquid SCN. The samples were processed in the Pore Formation and Mobility Investigation (PFMI) apparatus that is placed in the glovebox facility (GBX) aboard the ISS. Experimental processing parameters of temperature gradient and translation speed, as well as camera settings, were remotely monitored and manipulated from the ground Telescience Center (TSC) at the Marshall Space Flight Center. During the experiments, the sample is first subjected to a unidirectional melt back, generally at 10 microns per second, with a constant temperature gradient ahead of the melting interface. The temperatures in the sample are monitored by six in situ thermocouples. Real time visualization of the controlled directional melt back shows bubbles of different sizes initiating at the melt interface and, upon dislodging from the melting solid, migrating at different speeds into the temperature field ahead of them, before coming to rest. The thermocapillary flow field set up in the melt, ahead of the interface, is dramatic in the context of the large bubbles, and plays a major role in dislodging the bubble. A preliminary analysis of the observed bubble formation and mobility during melt back and its implication to future microgravity experiments is presented and discussed.

  11. Bubble Formation and Transport during Microgravity Materials Processing: Model Experiments on the Space Station

    NASA Technical Reports Server (NTRS)

    Grugel, R. N.; Anilkumar, A. V.; Lee, C. P.

    2003-01-01

    Flow Visualization experiments on the controlled melting and solidification of succinonitrile were conducted in the glovebox facility of the International Space Station (ISS). The experimental samples were prepared on ground by filling glass tubes, 1 cm ID and approximately 30 cm in length, with pure succinonitrile (SCN) under 450 millibar of nitrogen. Porosity in the samples arose from natural shrinkage, and in some cases by direct insertion of nitrogen bubbles, during solidification of the liquid SCN. The samples were processed in the Pore Formation and Mobility Investigation (PFMI) apparatus that is placed in the glovebox facility (GBX) aboard the ISS. Experimental processing parameters of temperature gradient and translation speed, as well as camera settings, were remotely monitored and manipulated from the ground Telescience Center (TSC) at the Marshall Space Flight Center. During the experiments, the sample is first subjected to a unidirectional melt back, generally at 10 microns per second, with a constant temperature gradient ahead of the melting interface. The temperatures in the sample are monitored by six in situ thermocouples. Real time visualization of the controlled directional melt back shows bubbles of different sizes initiating at the melt interface and, upon dislodging from the melting solid, migrating at different speeds into the temperature field ahead of them, before coming to rest. The thermocapillary flow field set up in the melt, ahead of the interface, is dramatic in the context of the large bubbles, and plays a major role in dislodging the bubble. A preliminary analysis of the observed bubble formation and mobility during melt back and its implication to future microgravity experiments is presented and discussed.

  12. Cosmochemical evidence for astrophysical processes during the formation of our solar system

    PubMed Central

    MacPherson, Glenn J.; Boss, Alan

    2011-01-01

    Through the laboratory study of ancient solar system materials such as meteorites and comet dust, we can recognize evidence for the same star-formation processes in our own solar system as those that we can observe now through telescopes in nearby star-forming regions. High temperature grains formed in the innermost region of the solar system ended up much farther out in the solar system, not only the asteroid belt but even in the comet accretion region, suggesting a huge and efficient process of mass transport. Bi-polar outflows, turbulent diffusion, and marginal gravitational instability are the likely mechanisms for this transport. The presence of short-lived radionuclides in the early solar system, especially 60Fe, 26Al, and 41Ca, requires a nearby supernova shortly before our solar system was formed, suggesting that the Sun was formed in a massive star-forming region similar to Orion or Carina. Solar system formation may have been “triggered” by ionizing radiation originating from massive O and B stars at the center of an expanding HII bubble, one of which may have later provided the supernova source for the short-lived radionuclides. Alternatively, a supernova shock wave may have simultaneously triggered the collapse and injected the short-lived radionuclides. Because the Sun formed in a region where many other stars were forming more or less contemporaneously, the bi-polar outflows from all such stars enriched the local region in interstellar silicate and oxide dust. This may explain several observed anomalies in the meteorite record: a near absence of detectable (no extreme isotopic properties) presolar silicate grains and a dichotomy in the isotope record between 26Al and nucleosynthetic (nonradiogenic) anomalies. PMID:22106251

  13. The Formation Process of Silico-Ferrite of Calcium (SFC) from Binary Calcium Ferrite

    NASA Astrophysics Data System (ADS)

    Ding, Xiang; Guo, Xing-Min

    2014-08-01

    Silico-ferrite of calcium (SFC) is a significant equilibrium crystalline phase in the Fe2O3-CaO-SiO2 (FCS) ternary system and a key bonding phase in the sintering process of fine iron ore. In this work, the formation process of SFC from binary calcium ferrite has been determined by X-ray diffraction and field-emission scanning electron microscopy. Experiments were carried out under air at 1473 K (1200 °C) by adding SiO2 and Fe2O3 into CaO·Fe2O3 (CF). It was found that the formation of SFC is dominated by solid-state reactions in the FCS ternary system, in which Fe2O3 reacts with CaO·Fe2O3 to form the binary calcium ferrite phase. The chemical composition of binary calcium ferrite is Ca2.5Fe15.5O25 and approximately Ca2Fe12O20 (CaO·3Fe2O3). Then Si4+ and Ca2+ ions take the place of Fe3+ ion in preference located on the octahedral layers which belongs to (0 0 18) plane of binary calcium ferrite. The crystal structure of binary calcium ferrite gradually transforms from orthorhombic to triclinic, and the grain is refined with the addition of silica due to the smaller radius of Si4+ ion. A solid solution SFC forms completely when the content of SiO2 reaches approximately 3.37 wt pct at 1473 K (1200 °C).

  14. Nano-Resolution X-ray Tomography for Deciphering Wiring Diagram of Mammalian Brain

    NASA Astrophysics Data System (ADS)

    Mizutani, H.; Sagara, H.; Takeuchi, A.; Ohigashi, T.; Yashiro, W.; Uesugi, K.; Suzuki, Y.; Momose, A.; Takagi, T.

    2011-09-01

    Neural circuits in the central nervous system are the substrate of various high-order brain functions. However, little is known about the mechanisms underlying neuronal information processing in the brain. Anatomical and functional graph structures of neural networks with actual connections will provide us with perspectives to elucidate the brain complexity. Here, we aim to develop a three-dimensional mouse brain atlas of neural circuits using nano-resolution x-ray tomography by synchrotron radiation. In addition to identifying a large number of synapses, our research will also clarify the structure of neuronal networks for understanding the most complex organ in the body. In this study, we observed metal-stained biological tissues of the mouse brain using hard x-ray Zernike-type phase-contrast microscopy with 60-nm resolution at SPring-8. As a result, the nano-resolution hard x-ray phase-contrast microscope revealed nerve fibers and organelles including mitochondria and synapses in the neural tissue. In the near future, this information will be utilized to begin deciphering the wiring diagram of the brain by using nano-resolution x-ray tomography.

  15. Zeolite Formation and Weathering Processes Within the Martian Regolith: An Antarctic Analog

    NASA Technical Reports Server (NTRS)

    Gibson, E. K.; McKay, D. S.; Wentworth, S. J.; Socki, R. A.

    2003-01-01

    As more information is obtained about the nature of the surface compositions and processes operating on Mars, it is clear that significant erosional and depositional features are present on the surface. Apparent aqueous or other fluid activity on Mars has produced many of the erosional and outflow features observed. Evidence of aqueous activity on Mars has been reported by earlier studies. Gooding and colleagues championed the cause of pre-terrestrial aqueous alteration processes recorded in Martian meteorites. Oxygen isotope studies on Martian meteorites by Karlsson et al. and Romenek et al. gave evidence for two separate water reservoirs on Mars. The oxygen isotopic compositions of the host silicate minerals was different from the oxygen isotopic composition of the secondary alteration products within the SNC meteorites. This implied that the oxygen associated with fluids which produced the secondary alteration was from volatiles which were possibly added to the planetary inventory after formation of the primary silicates from which the SNC s were formed. The source of the oxygen may have been from a cometary or volatile-rich veneer added to the planet in its first 600 million years.

  16. BIOFILM FORMATION OF Vibrio cholerae ON STAINLESS STEEL USED IN FOOD PROCESSING

    PubMed Central

    FERNÁNDEZ-DELGADO, Milagro; ROJAS, Héctor; DUQUE, Zoilabet; SUÁREZ, Paula; CONTRERAS, Monica; GARCÍA-AMADO, M. Alexandra; ALCIATURI, Carlos

    2016-01-01

    Vibrio cholerae represents a significant threat to human health in developing countries. This pathogen forms biofilms which favors its attachment to surfaces and its survival and transmission by water or food. This work evaluated the in vitro biofilm formation of V. cholerae isolated from clinical and environmental sources on stainless steel of the type used in food processing by using the environmental scanning electron microscopy (ESEM). Results showed no cell adhesion at 4 h and scarce surface colonization at 24 h. Biofilms from the environmental strain were observed at 48 h with high cellular aggregations embedded in Vibrio exopolysaccharide (VPS), while less confluence and VPS production with microcolonies of elongated cells were observed in biofilms produced by the clinical strain. At 96 h the biofilms of the environmental strain were released from the surface leaving coccoid cells and residual structures, whereas biofilms of the clinical strain formed highly organized structures such as channels, mushroom-like and pillars. This is the first study that has shown the in vitro ability of V. cholerae to colonize and form biofilms on stainless steel used in food processing. PMID:27253749

  17. ATPase activity of the DEAD-box protein Dhh1 controls processing body formation

    PubMed Central

    Mugler, Christopher Frederick; Hondele, Maria; Heinrich, Stephanie; Sachdev, Ruchika; Vallotton, Pascal; Koek, Adriana Y; Chan, Leon Y; Weis, Karsten

    2016-01-01

    Translational repression and mRNA degradation are critical mechanisms of posttranscriptional gene regulation that help cells respond to internal and external cues. In response to certain stress conditions, many mRNA decay factors are enriched in processing bodies (PBs), cellular structures involved in degradation and/or storage of mRNAs. Yet, how cells regulate assembly and disassembly of PBs remains poorly understood. Here, we show that in budding yeast, mutations in the DEAD-box ATPase Dhh1 that prevent ATP hydrolysis, or that affect the interaction between Dhh1 and Not1, the central scaffold of the CCR4-NOT complex and an activator of the Dhh1 ATPase, prevent PB disassembly in vivo. Intriguingly, this process can be recapitulated in vitro, since recombinant Dhh1 and RNA, in the presence of ATP, phase-separate into liquid droplets that rapidly dissolve upon addition of Not1. Our results identify the ATPase activity of Dhh1 as a critical regulator of PB formation. DOI: http://dx.doi.org/10.7554/eLife.18746.001 PMID:27692063

  18. Formation of semisolid, oligomerized aqueous SOA: lab simulations of cloud processing.

    PubMed

    Hawkins, Lelia N; Baril, Molly J; Sedehi, Nahzaneen; Galloway, Melissa M; De Haan, David O; Schill, Gregory P; Tolbert, Margaret A

    2014-02-18

    Glyoxal, methylglyoxal, glycolaldehyde, and hydroxyacetone form N-containing and oligomeric compounds during simulated cloud processing with small amines. Using a novel hygroscopicity tandem differential mobility analysis (HTDMA) system that allows varied humidification times, the hygroscopic growth (HG) of each of the resulting products of simulated cloud processing was measured. Continuous water uptake (gradual deliquescence) was observed beginning at ∼ 40% RH for all aldehyde-methylamine products. Particles containing ionic reaction products of either glyoxal or glycine were most hygroscopic, with HG between 1.16 and 1.20 at 80% RH. Longer humidification times (up to 20 min) produced an increase in growth factors for glyoxal-methylamine (19% by vol) and methylglyoxal-methylamine (8% by vol) aerosol, indicating that unusually long equilibration times can be required for HTDMA measurements of such particles. Glyoxal- and methylglyoxal-methylamine aerosol particles shattered in Raman microscopy impact-flow experiments, revealing that the particles were semisolid. Similar experiments on glycolaldehyde- and hydroxyacetone-methylamine aerosol found that the aerosol particles were liquid when dried for <1 h, but semisolid when dried for 20 h under ambient conditions. The RH required for flow (liquification) during humidification experiments followed the order methylglyoxal > glyoxal > glycolaldehyde = hydroxyacetone, likely caused by the speed of oligomer formation in each system.

  19. What is the deficit in phonological processing deficits: Auditory sensitivity, masking, or category formation?

    PubMed Central

    Nittrouer, Susan; Shune, Samantha; Lowenstein, Joanna H.

    2012-01-01

    Although children with language impairments, including those associated with reading, usually demonstrate deficits in phonological processing, there is minimal agreement as to the source of those deficits. This study examined two problems hypothesized to be possible sources: either poor auditory sensitivity to speech-relevant acoustic properties, mainly formant transitions, or enhanced masking of those properties. Adults and 8-year-olds with and without phonological processing deficits (PPD) participated. Children with PPD demonstrated weaker abilities than children with typical language development (TLD) in reading, sentence recall, and phonological awareness. Dependent measures were: 1) word recognition; 2) discrimination of spectral glides; and 3) phonetic judgments based on spectral and temporal cues. All tasks were conducted in quiet and in noise. Children with PPD showed neither poorer auditory sensitivity nor greater masking than adults and children with TLD, but did demonstrate an unanticipated deficit in category formation for non-speech sounds. These results suggest that these children may have an underlying deficit in perceptually organizing sensory information to form coherent categories. PMID:21109251

  20. BIOFILM FORMATION OF Vibrio cholerae ON STAINLESS STEEL USED IN FOOD PROCESSING.

    PubMed

    Fernández-Delgado, Milagro; Rojas, Héctor; Duque, Zoilabet; Suárez, Paula; Contreras, Monica; García-Amado, M Alexandra; Alciaturi, Carlos

    2016-01-01

    Vibrio cholerae represents a significant threat to human health in developing countries. This pathogen forms biofilms which favors its attachment to surfaces and its survival and transmission by water or food. This work evaluated the in vitro biofilm formation of V. cholerae isolated from clinical and environmental sources on stainless steel of the type used in food processing by using the environmental scanning electron microscopy (ESEM). Results showed no cell adhesion at 4 h and scarce surface colonization at 24 h. Biofilms from the environmental strain were observed at 48 h with high cellular aggregations embedded in Vibrio exopolysaccharide (VPS), while less confluence and VPS production with microcolonies of elongated cells were observed in biofilms produced by the clinical strain. At 96 h the biofilms of the environmental strain were released from the surface leaving coccoid cells and residual structures, whereas biofilms of the clinical strain formed highly organized structures such as channels, mushroom-like and pillars. This is the first study that has shown the in vitro ability of V. cholerae to colonize and form biofilms on stainless steel used in food processing.

  1. Weathering processes and pickeringite formation in a sulfidic schist: a consideration in acid precipitation neutralization studies

    SciTech Connect

    Parnell, R.A. Jr.

    1983-01-01

    Extremely low abrasion pH values (2.8-3.3) characterize the weathering products of the Partridge Formation, a Middle-Ordovician metamorphosed, black, sulfidic shale. The local occurrence is observed of two sulfates that are rare in the Northeast: pickeringite and jarosite. X-ray diffraction studies of the weathering residues and the sulfate efflorescences have also identified dioctahedral and trioctahedral illite, kaolinite, vermiculite, and an 11-12 Angstrom phase, thought to be a type of randomly-interstratified biotite-vermiculite. From the mineralogical studies, qualitative weathering processes for the schist are formulated. A probable mechanism for the intense chemical weathering of the schist appears to be oxidation of iron sulfides to form iron oxide-hydroxides, sulfates, and sulfuric acid. This natural weathering process is proposed as an analog to anthropogenic low pH rock weathering resulting from acid precipitation. In the Northeast, natural weathering rates, may, in places, significantly affect the water chemistry and mineralogy used to quantify total (natural plus anthropogenic) weathering and leaching rates. 27 references, 4 figures.

  2. Formation risk of toxic and other unwanted compounds in pressure-assisted thermally processed foods.

    PubMed

    Bravo, K Segovia; Ramírez, R; Durst, R; Escobedo-Avellaneda, Z J; Welti-Chanes, J; Sanz, P D; Torres, J A

    2012-01-01

    Consumers demand, in addition to excellent eating quality, high standards of microbial and chemical safety in shelf-stable foods. This requires improving conventional processing technologies and developing new alternatives such as pressure-assisted thermal processing (PATP). Studies in PATP foods on the kinetics of chemical reactions at temperatures (approximately 100 to 120 °C) inactivating bacterial spores in low-acid foods are severely lacking. This review focuses on a specific chemical safety risk in PATP foods: models predicting if the activation volume value (V(a) ) of a chemical reaction is positive or negative, and indicating if the reaction rate constant will decrease or increase with pressure, respectively, are not available. Therefore, the pressure effect on reactions producing toxic compounds must be determined experimentally. A recent model solution study showed that acrylamide formation, a potential risk in PATP foods, is actually inhibited by pressure (that is, its V(a) value must be positive). This favorable finding was not predictable and still needs to be confirmed in food systems. Similar studies are required for other reactions producing toxic compounds including polycyclic aromatic hydrocarbons, heterocyclic amines, N-nitroso compounds, and hormone like-peptides. Studies on PATP inactivation of prions, and screening methods to detect the presence of other toxicity risks of PATP foods, are also reviewed.

  3. Influence of Powder Metallurgical Processing Routes on Phase Formations in a Multicomponent NbSi-Alloy

    NASA Astrophysics Data System (ADS)

    Seemüller, C.; Hartwig, T.; Mulser, M.; Adkins, N.; Wickins, M.; Heilmaier, M.

    2014-09-01

    Refractory metal silicide composites on the basis of Nbss-Nb5Si3 have been investigated as potential alternatives for nickel-base superalloys for years because of their low densities and good high-temperature strengths. NbSi-based composites are typically produced by arc-melting or casting. Samples in this study, however, were produced by powder metallurgy because of the potential for near net-shape component fabrication with very homogeneous microstructures. Either gas atomized powder or high-energy mechanically alloyed elemental powders were compacted by powder injection molding or hot isostatic pressing. Heat treatments were applied for phase stability evaluation. Slight compositional changes (oxygen, nitrogen, or iron) introduced by the processing route, i.e., powder production and consolidation, can affect phase formations and phase transitions during the process. Special focus is put on the distinction between different silicides (Nb5Si3 and Nb3Si) and silicide modifications (α-, β-, and γ-Nb5Si3), respectively. These were evaluated by x-ray diffraction and energy-dispersive spectroscopy measurements with the additional inclusion of thermodynamic calculations using the calculated phase diagram method.

  4. Carbon Disulfide (CS2) Mechanisms in Formation of Atmospheric Carbon Dioxide (CO2) Formation from Unconventional Shale Gas Extraction and Processing Operations and Global Climate Change.

    PubMed

    Rich, Alisa L; Patel, Jay T

    2015-01-01

    Carbon disulfide (CS2) has been historically associated with the production of rayon, cellophane, and carbon tetrachloride. This study identifies multiple mechanisms by which CS2 contributes to the formation of CO2 in the atmosphere. CS2 and other associated sulfide compounds were found by this study to be present in emissions from unconventional shale gas extraction and processing (E&P) operations. The breakdown products of CS2; carbonyl sulfide (COS), carbon monoxide (CO), and sulfur dioxide (SO2) are indirect greenhouse gases (GHGs) that contribute to CO2 levels in the atmosphere. The heat-trapping nature of CO2 has been found to increase the surface temperature, resulting in regional and global climate change. The purpose of this study is to identify five mechanisms by which CS2 and the breakdown products of CS2 contribute to atmospheric concentrations of CO2. The five mechanisms of CO2 formation are as follows: Chemical Interaction of CS2 and hydrogen sulfide (H2S) present in natural gas at high temperatures, resulting in CO2 formation;Combustion of CS2 in the presence of oxygen producing SO2 and CO2;Photolysis of CS2 leading to the formation of COS, CO, and SO2, which are indirect contributors to CO2 formation;One-step hydrolysis of CS2, producing reactive intermediates and ultimately forming H2S and CO2;Two-step hydrolysis of CS2 forming the reactive COS intermediate that reacts with an additional water molecule, ultimately forming H2S and CO2. CS2 and COS additionally are implicated in the formation of SO2 in the stratosphere and/or troposphere. SO2 is an indirect contributor to CO2 formation and is implicated in global climate change.

  5. Determining if Active Learning through a Formative Assessment Process Translates to Better Performance in Summative Assessment

    ERIC Educational Resources Information Center

    Grosas, Aidan Bradley; Raju, Shiwani Rani; Schuett, Burkhardt Siegfried; Chuck, Jo-Anne; Millar, Thomas James

    2016-01-01

    Formative assessment used in a level 2 unit, Immunology, gave outcomes that were both surprising and applicable across disciplines. Four formative tests were given and reviewed during class time. The students' attitudes to formative assessment were evaluated using questionnaires and its effectiveness in closing the gap was measured by the…

  6. Formation and Processing of Secondary Organic Aerosol from Catechol as a Model for Atmospheric HULIS

    NASA Astrophysics Data System (ADS)

    Ofner, Johannes; Krüger, Heinz-Ulrich; Grothe, Hinrich; Zetzsch, Cornelius

    2010-05-01

    A particular fraction of the secondary organic aerosol (SOA) termed HUmic Like Substances (HULIS) attracted attention only recently in atmospheric aerosol, initiating a discourse about their aromaticity and other properties, such as reactivity and hygroscopicity. A major portion of HULIS originates from volatile organic compounds, which are formed by abiotic oxidation reactions involving mainly OH radicals, ozone, nitrogen oxides and possibly halogens. Subsequently, the particles provide surface for heterogeneous reactions with atmospheric trace gases. Thus, aerosol smog-chamber studies with appropriate precursors are needed to generate SOA with HULIS qualities in situ inside the smog chamber and study their possible interactions. Catechol and guaiacol were chosen as aromatic precursors for synthetic HULIS production. The SOA was produced in a 700 L aerosol smog chamber, equipped with a solar simulator. SOA formation from each precursor was investigated at simulated environmental conditions (humidity, light, and presence of oxidizers) and characterized with respect to HULIS properties by particle classifiers, Fourier Transform IR spectroscopy (by long-path absorption and attenuated total reflection), UV/VIS spectroscopy, high-resolution mass-spectroscopy and temperature-programmed-desorption mass-spectrometry. High-resolution imaging was obtained using Field Emission Gun Scanning Electron Microscopy (FEGSEM). After HULIS formation the aerosol particles were exposed to atmospheric halogen species to study their processing with those trace gases, released by sea salt-activation. Those investigations show that aromatic precursors like catechol and guaiacol are suitable to form synthetic HULIS for laboratory-scale measurements with physical and chemical properties described in literature. However, sunlight and relative humidity play a major role in particle production and composition of functional groups, which are the anchor points for heterogeneous atmospheric

  7. Observations and Simulations of Formation of Broad Plasma Depletions Through Merging Process

    NASA Technical Reports Server (NTRS)

    Huang, Chao-Song; Retterer, J. M.; Beaujardiere, O. De La; Roddy, P. A.; Hunton, D.E.; Ballenthin, J. O.; Pfaff, Robert F.

    2012-01-01

    Broad plasma depletions in the equatorial ionosphere near dawn are region in which the plasma density is reduced by 1-3 orders of magnitude over thousands of kilometers in longitude. This phenomenon is observed repeatedly by the Communication/Navigation Outage Forecasting System (C/NOFS) satellite during deep solar minimum. The plasma flow inside the depletion region can be strongly upward. The possible causal mechanism for the formation of broad plasma depletions is that the broad depletions result from merging of multiple equatorial plasma bubbles. The purpose of this study is to demonstrate the feasibility of the merging mechanism with new observations and simulations. We present C/NOFS observations for two cases. A series of plasma bubbles is first detected by C/NOFS over a longitudinal range of 3300-3800 km around midnight. Each of the individual bubbles has a typical width of approx 100 km in longitude, and the upward ion drift velocity inside the bubbles is 200-400 m/s. The plasma bubbles rotate with the Earth to the dawn sector and become broad plasma depletions. The observations clearly show the evolution from multiple plasma bubbles to broad depletions. Large upward plasma flow occurs inside the depletion region over 3800 km in longitude and exists for approx 5 h. We also present the numerical simulations of bubble merging with the physics-based low-latitude ionospheric model. It is found that two separate plasma bubbles join together and form a single, wider bubble. The simulations show that the merging process of plasma bubbles can indeed occur in incompressible ionospheric plasma. The simulation results support the merging mechanism for the formation of broad plasma depletions.

  8. Hydrocarbon transport and shearing processes in the Antelope Shale, Monterey Formation, San Joaquin Valley, California

    SciTech Connect

    Dholakia, S.K.; Aydin, A.; Pollard, D.D. )

    1996-01-01

    An essential component of the development and management of a fractured reservoir is the basic understanding of the fracture system and its effect on hydrocarbon flow. In the Antelope Shale, a siliceous shale member of the Monterey Formation in the Buena Vista Hills field (BVH), San Joaquin Valley (SJV), the relationship between the fracture system and hydrocarbon productivity is poorly understood. An integrative approach, employing both geological and geophysical methods, to fracture characterization in the Antelope Shale is important for a better understanding of the connected fracture network and for identifying hydrocarbon-carrying fractures. This knowledge will aid in future reservoir management plans for the BVH field, specifically CO[sub 2] enhanced oil recovery from the existing reservoir. Field studies of the Antelope Shale at Chico Martinez Creek in the SJV demonstrate the importance of shearing processes for the migration of hydrocarbons. Hydrocarbons primarily occur in brecciated zones which are oriented parallel to bedding. The internal architecture of early stage breccia zones is well-organized with sets of hydrocarbon-stained fractures oriented both at high angles and parallel to bedding. In later stage breccia zones, internal organization is disrupted and consists of fragments of the host rock surrounded by hydrocarbons. Subsurface studies which include core and FMS data demonstrate comparable shear-related features in the Monterey Formation. Oil-stained breccia zones are observed in core from the Antelope Shale from a field near BVH. Breccia zones are documented in FMS data from offshore Monterey fields and similar features are being sought in FMS data from SJV in Antelope Shale.

  9. Hydrocarbon transport and shearing processes in the Antelope Shale, Monterey Formation, San Joaquin Valley, California

    SciTech Connect

    Dholakia, S.K.; Aydin, A.; Pollard, D.D.

    1996-12-31

    An essential component of the development and management of a fractured reservoir is the basic understanding of the fracture system and its effect on hydrocarbon flow. In the Antelope Shale, a siliceous shale member of the Monterey Formation in the Buena Vista Hills field (BVH), San Joaquin Valley (SJV), the relationship between the fracture system and hydrocarbon productivity is poorly understood. An integrative approach, employing both geological and geophysical methods, to fracture characterization in the Antelope Shale is important for a better understanding of the connected fracture network and for identifying hydrocarbon-carrying fractures. This knowledge will aid in future reservoir management plans for the BVH field, specifically CO{sub 2} enhanced oil recovery from the existing reservoir. Field studies of the Antelope Shale at Chico Martinez Creek in the SJV demonstrate the importance of shearing processes for the migration of hydrocarbons. Hydrocarbons primarily occur in brecciated zones which are oriented parallel to bedding. The internal architecture of early stage breccia zones is well-organized with sets of hydrocarbon-stained fractures oriented both at high angles and parallel to bedding. In later stage breccia zones, internal organization is disrupted and consists of fragments of the host rock surrounded by hydrocarbons. Subsurface studies which include core and FMS data demonstrate comparable shear-related features in the Monterey Formation. Oil-stained breccia zones are observed in core from the Antelope Shale from a field near BVH. Breccia zones are documented in FMS data from offshore Monterey fields and similar features are being sought in FMS data from SJV in Antelope Shale.

  10. Reading Hidden Messages Through Deciphered Manual Alphabets on Classic Artwork

    NASA Astrophysics Data System (ADS)

    Castronovo, Joseph Anthony, Jr.

    1998-10-01

    Decipherment is the tool used to uncover several types of hand signs that played vital roles in the creation of hidden messages in classic artwork. A 3,100 B.C. bas-relief of The 'Kaph' Telescope, formerly named The Narmer Palette, and Michaelangelo Buonarrotte's Battle of Cascina of 1506 were two key works of art that show certain similarities even though separated by 4,500 years. It is evident that Renaissance humanists provided artists with certain knowledge of the ancients. Results of incorporating a number of minor works of art showed that the competence of ancient Egyptians, Cretans and Australian Aboriginals, to name a few, as astronomers, was underestimated. Some deciphered Indus seals attested to a global understanding of the universe, with Gemini and the star of Thuban at the center of their attention. Certain forms of secrecy had to be undertaken for various reasons throughout the millennia. Three examples are: (1) In Italy, to keep controversial and truthful teachings discreet and hidden, artists embedded them in artwork long before the plight of Galileo Galilei and his discoveries. (2) Among Jewish Kabbalists, a well-known design was obscured in The Arnolfini Wedding painting for fear it would be lost due to persecution. (3) Michaelangelo Buonarrotte indicated several meanings through the hands of The Statue of Moses. They were overlooked by several societies, including the gesticulating culture of Italy, because they oppressed the value of signed languages. Spatial decipherment may testify to a need for the restoration of a spatial writing system for expanded linguistic accessibility. A 21st century model community for sign language residents and employees will benefit visual learners, particularly visual artists and non-phonetic decipherers, to better uncover, understand and perhaps use ancient hand forms to restore ancient knowledge. Moreover, the National Association of Teaching English (NATE) has recently endorsed the addition of two skills

  11. The effect of dust and gas energetics on the clustered star formation process

    NASA Astrophysics Data System (ADS)

    Urban, Andrea

    The effect of dust/gas heating and cooling is shown to have a significant effect on the process of clustered star formation. Compared to an isothermal simulation, a simulation with a more accurate description of the equation of state produces an order of magnitude fewer stars as well as stars of much greater mass. The energetics algorithm used to calculate the dust and gas temperature includes the radiative heating of dust, dust-gas collisional heating/cooling, cosmic-ray heating, and molecular cooling. It uses DUSTY, a spherical continuum radiative transfer code, to model the dust temperature distribution around young stellar objects with various luminosities and surrounding gas and dust density distributions. The gas temperature is then determined by assuming energy balance. Before the complete energetics algorithm is included in a simulation, first only the dust heating component is included. The gas temperature is then set solely by the dust temperature. The resultant mass functions of our simulations which include heating are compared to those which assume an isothermal equation of state. We find that including dust heating severely limits star formation; we form at least an order of magnitude fewer objects when we include dust heating compared to an isothermal simulation. The mass functions from our simulations which include heating are much more similar than the mass functions from our isothermal simulations to the observed mass functions, in that they are able to form high-mass stars ( M [Special characters omitted.] 10[Special characters omitted.] ). The distribution of the high-mass objects is well- approximated by the Salpeter initial mass function. Including the complete energetics algorithm in a simulation produces results similar to a simulation with only dust heating. Both simulations have similar density profile parameters. The mass accretion, mass, and luminosity evolution of the sinks is also similar. The average temperature, however, is cooler

  12. Physical Characteristics, Geologic Setting, and Possible Formation Processes of Spring Deposits on Mars Based on Terrestrial Analogs

    NASA Technical Reports Server (NTRS)

    Crumpler, L. S.

    2003-01-01

    Spring formation is a predicted consequence of the interaction of former Martian aquifers with structures common to Mars, including basin margins, Tharsis structures, and other structural deformation characteristics. The arid environment and high abundance of water soluble compounds in the crust will have likewise encouraged spring deposit formation at spring sites. Such spring deposits may be recognized from morphological criteria if the characteristics of formation and preservation are understood. An important first step in the current Mars exploration strategy [10] is the detection of sites where there is evidence for past or present near-surface water on Mars. This study evaluates the large-scale morphology of spring deposits and the physical processes of their formation, growth, and evolution in terms that relate to (1) their identification in image data, (2) their formation, evolution, and preservation in the environment of Mars, and (3) their potential as sites of long-term or late stage shallow groundwater emergence at the surface of Mars.

  13. An Insight to the Modeling of 1 × 1 Rib Loop Formation Process on Circular Weft Knitting Machine using Computer

    NASA Astrophysics Data System (ADS)

    Ray, Sadhan Chandra

    2015-10-01

    The mechanics of single jersey loop formation is well-reported is literature. However, as the concept of any model of double jersey loop formation process is not available in accessible international literature. Therefore, it was planned to develop a model of 1 × 1 rib loop formation process on dial and cylinder machine using computer so that the influence of various input variables on the final loop length as well on the profile of tension on the yarn inside Knitting Zone (KZ) can be understood. The model provides an insight into the mechanics of 1 × 1 rib loop formation system on dial and cylinder machine. Besides, the degree of agreement between predicted and measured values of loop length and cam forces as well as theoretical analysis of the model have justified the acceptability of the model.

  14. The synthesis and formation process of a new cubic conductive Cu7O(8-y)(NO3) compound

    NASA Astrophysics Data System (ADS)

    Yazawa, Ichiro; Sugise, Ryoji; Terada, Norio; Jo, Masatoshi; Oka, Kunihiko

    1990-08-01

    The synthesis and formation process of a new cubic conductive Cu7O(8-y)(NO3) compound was studied. This material was formed as an intermediate compound in the decomposition process of copper nitrate by a firing process in oxygen flowing gas. It has a CuO2 plane in its lattice structure and is a parent material of the new metallic copper oxide compounds.

  15. Zeolite Formation and Weathering Processes in Dry Valleys of Antartica: Martian Analogs

    NASA Technical Reports Server (NTRS)

    Gibson, E. K., Jr.; Wentworth, S. J.; McKay, D. S.; Socki, R. A.

    2004-01-01

    been identified within the soil columns because they are fragile; i.e. they are euhedral, unabraded, and unfractured, strongly suggesting in situ formation. Their presence in Antarctic samples is another indication that diagenic processes are active in cold-desert environments. The presence of zeolites, and other clays along with halites, sulfates, carbonates, and hydrates are to be expected within the soil columns on Mars at the Gusev and Isidis Planitia regions. The presence of such water-bearing minerals beneath the surface supplies one of the requirements to support biological activity on Mars.

  16. How far can we go in hydrological modelling without any knowledge of runoff formation processes?

    NASA Astrophysics Data System (ADS)

    Ayzel, Georgy

    2016-04-01

    Hydrological modelling is a challenging scientific issue for the last 50 years and tend to be it further because of the highest level of runoff formation processes complexity at the different spatio-temporal scales. Enormous number of modelling-related papers have submitted to the top-ranked journals every year, but in this publication speed race authors have pay increasing attention to the models and data they use by itself rather than underlying watershed processes. Great community effort of the free and open-source models sharing with high availability of hydrometeorological data sources led to conceptual shifting paradigm of hydrological science to the technical-oriented direction. In the third-world countries this shifting is more clear by the reason of field studies absence and obligatory requirement of practical significance of the research supported by the government funds. As a result we get a state of hydrological modelling discipline closer to the aim of high Nash-Sutcliffe efficiency (NSE) achievement rather than watershed processes understanding. Both lumped physically-based land-surface model SWAP (Soil Water - Atmosphere - Plants) and SCE-UA (Shuffled Complex Evolution method developed at The University of Arizona) technique for robust model parameters search were used for the runoff modelling of 323 MOPEX watersheds. No one special data analysis and expert knowledge-based decisions were not performed. Median value of NSE is 0.652 and 90% of watersheds have efficiency bigger than 0.5. Thus without any information of particular features of each watershed satisfactory modelling results were obtained. To prove our conclusions we build cutting-edge conceptual rainfall-runoff model based on decision trees and adaptive boosting machine learning algorithms for the one small watershed in USA. No one special data analysis or feature engineering was not performed too. Obtained results demonstrate great model prediction power both for learning and testing

  17. Insights Into Sill Formation Processes From Particle Image Velocimetry (PIV) Analysis of Layered Elastic Media Experiments

    NASA Astrophysics Data System (ADS)

    Kavanagh, J. L.; Boutelier, D. A.; Cruden, A. R.

    2012-12-01

    A key issue in magma intrusion mechanics is constraining the conditions required to initiate sill formation from feeder dykes. To investigate these processes, we present a series of layered gelatine analogue experiments monitored with a Particle Image Velocimetry (PIV) system to document the fluid dynamics in the magma and small-scale deformation processes in the host material as a sill is formed along a weak contact beneath a more rigid layer. Gelatine is a good crustal analogue material to study the dynamics of dyke and sill propagation in the crust. Although gelatine is viscoelastic, tests carried out using a rheometer show that at experimental conditions the gelatine behaves as an almost ideal elastic material at 5-10 °C. Forty litres of hot liquid gelatine is poured into a clear-perspex tank and left to solidify in a fridge at ~5 °C. Experiments are prepared comprising multiple layers, with small strength contrasts (comparable to those between crustal strata) created by varying the gelatine concentration and allowing sufficient time for it to reach the plateau Young's modulus. Both strong and weak interface strengths are investigated by varying the extent of welding between the layers. Injection of dyed water (the magma analogue) into the solid gelatine from below causes a penny-shaped experimental dyke to form. With a constant driving pressure, the propagating experimental dyke becomes arrested beneath a more rigid layer if the Young's modulus contrast is greater than 12%. In the case of a weak interface, a sill is formed by intrusion along the contact between the layers; if the interface is strong a blade-like dyke forms. To monitor displacements within the gelatine using the PIV technique, neutrally buoyant polyamide reflective particles are added to the gelatine during experiment preparation. Two high-speed cameras are positioned outside the tank in a plane perpendicular to the strike of the experimental feeder dyke, and parallel to a high-power laser

  18. Comparison of biofilm formation and motility processes in arsenic-resistant Thiomonas spp. strains revealed divergent response to arsenite.

    PubMed

    Farasin, Julien; Koechler, Sandrine; Varet, Hugo; Deschamps, Julien; Dillies, Marie-Agnès; Proux, Caroline; Erhardt, Mathieu; Huber, Aline; Jagla, Bernd; Briandet, Romain; Coppée, Jean-Yves; Arsène-Ploetze, Florence

    2017-02-07

    Bacteria of the genus Thiomonas are found ubiquitously in arsenic contaminated waters such as acid mine drainage (AMD), where they contribute to the precipitation and the natural bioremediation of arsenic. In these environments, these bacteria have developed a large range of resistance strategies among which the capacity to form particular biofilm structures. The biofilm formation is one of the most ubiquitous adaptive response observed in prokaryotes to various stresses, such as those induced in the presence of toxic compounds. This study focused on the process of biofilm formation in three Thiomonas strains (CB1, CB2 and CB3) isolated from the same AMD. The results obtained here show that these bacteria are all capable of forming biofilms, but the architecture and the kinetics of formation of these biofilms differ depending on whether arsenite is present in the environment and from one strain to another. Indeed, two strains favoured biofilm formation, whereas one favoured motility in the presence of arsenite. To identify the underlying mechanisms, the patterns of expression of some genes possibly involved in the process of biofilm formation were investigated in Thiomonas sp. CB2 in the presence and absence of arsenite, using a transcriptomic approach (RNA-seq). The findings obtained here shed interesting light on how the formation of biofilms, and the motility processes contribute to the adaptation of Thiomonas strains to extreme environments.

  19. Boric Acid Reduces the Formation of DNA Double Strand Breaks and Accelerates Wound Healing Process.

    PubMed

    Tepedelen, Burcu Erbaykent; Soya, Elif; Korkmaz, Mehmet

    2016-12-01

    Boron is absorbed by the digestive and respiratory system, and it was considered that it is converted to boric acid (BA), which was distributed to all tissues above 90 %. The biochemical essentiality of boron element is caused by boric acid because it affects the activity of several enzymes involved in the metabolism. DNA damage repair mechanisms and oxidative stress regulation is quite important in the transition stage from normal to cancerous cells; thus, this study was conducted to investigate the protective effect of boric acid on DNA damage and wound healing in human epithelial cell line. For this purpose, the amount of DNA damage occurred with irinotecan (CPT-11), etoposide (ETP), doxorubicin (Doxo), and H2O2 was determined by immunofluorescence through phosphorylation of H2AX((Ser139)) and pATM((Ser1981)) in the absence and presence of BA. Moreover, the effect of BA on wound healing has been investigated in epithelial cells treated with these agents. Our results demonstrated that H2AX((Ser139)) foci numbers were significantly decreased in the presence of BA while wound healing was accelerated by BA compared to that in the control and only drug-treated cells. Eventually, the results indicate that BA reduced the formation of DNA double strand breaks caused by agents as well as improving the wound healing process. Therefore, we suggest that boric acid has important therapeutical effectiveness and may be used in the treatment of inflammatory diseases where oxidative stress and wound healing process plays an important role.

  20. Formation Process of Relativistic Electron Flux Through Interaction with Chorus Emissions in the Earth's Inner Magnetosphere

    NASA Astrophysics Data System (ADS)

    Omura, Y.; Miyashita, Y.; Yoshikawa, M.; Summers, D.; Hikishima, M.; Ebihara, Y.; Kubota, Y.

    2015-12-01

    We perform test particle simulations of energetic electrons interacting with whistler-mode chorus emissions. We compute trajectories of a large number of electrons forming a delta function with the same energy and pitch angle. The electrons are launched at different locations along the magnetic field line and different timings with respect to a pair of chorus emissions generated at the magnetic equator. We follow the evolution of the delta function, and obtain a distribution function in energy and equatorial pitch angle, which is a numerical Green's function for one cycle of chorus wave-particle interaction. We obtain the Green's functions for the energy range 10 keV ˜ 6 MeV and all pitch angles greater than the loss cone angle. By taking the convolution integral of the Green's functions with the distribution function of the injected electrons repeatedly, we follow a long-time evolution of the distribution function. We find that the energetic electrons are accelerated effectively by relativistic turning acceleration and ultra-relativistic acceleration through nonlinear trapping by chorus emissions, and that these processes result in the rapid formation of a dumbbell distribution of highly relativistic electrons within a few minutes after the injection of tens of keV electrons.

  1. Case studies on the formation of chalcogenide self-assembled monolayers on surfaces and dissociative processes

    PubMed Central

    Bendounan, Azzedine; Harish, Makri Nimbegondi Kotresh; Giglia, Angelo; Kubsky, Stefan; Sirotti, Fausto; Pasquali, Luca; Sampath, Srinivasan

    2016-01-01

    Summary This report examines the assembly of chalcogenide organic molecules on various surfaces, focusing on cases when chemisorption is accompanied by carbon–chalcogen atom-bond scission. In the case of alkane and benzyl chalcogenides, this induces formation of a chalcogenized interface layer. This process can occur during the initial stages of adsorption and then, after passivation of the surface, molecular adsorption can proceed. The characteristics of the chalcogenized interface layer can be significantly different from the metal layer and can affect various properties such as electron conduction. For chalcogenophenes, the carbon–chalcogen atom-bond breaking can lead to opening of the ring and adsorption of an alkene chalcogenide. Such a disruption of the π-electron system affects charge transport along the chains. Awareness about these effects is of importance from the point of view of molecular electronics. We discuss some recent studies based on X-ray photoelectron spectroscopy that shed light on these aspects for a series of such organic molecules. PMID:26977383

  2. The processes of modified microareas formation in the bulk of porous glasses by laser radiation

    NASA Astrophysics Data System (ADS)

    Kostyuk, G. K.; Sergeev, M. M.; Yakovlev, E. B.

    2015-06-01

    The possibility of the formation of modified microareas (MAs) with changed optical properties in the bulk of porous glasses (PGs) with laser radiation is investigated. A laser module of continuous action with wavelength λ = 800 nm and power P = 120 mW was used as the source of radiation. The material used in the experiment was PG of 94.73 SiO2-4.97 B2O3-0.30 Na2O. A model that describes the processes taking place under laser radiation that lead to a modification of the glass is proposed. Our evaluation results based on experimental data are given. The results of an additional PG plate of the same composition impregnated with glycerol—a substance with a high degree of polarizability—during exposure experiments are also given. A fiber laser of continuous action with wavelength λ = 1070 nm and power P = 16.5 W was used as a source of radiation.

  3. Effect of plasma processing and organosilane modifications of polyethylene on Aeromonas hydrophila biofilm formation.

    PubMed

    Kregiel, Dorota; Niedzielska, Kamila

    2014-01-01

    The aim of our research was to study how the modifications of polyethylene--a material commonly used in medicine and water industry--influence bacterial cell attachment and biofilm formation. The native surface was activated and modified using two-step process consisting in the activation of native surface with a H2O vapor plasma followed by its treatment with various organosilanes, namely, [3(tertbutylamine-2hydroxy) propyloxypropyl] diethoxymethylsilane, 1H,1H,2H,2H-perfluorooctylmethyldimethoxysilane, dimethoxydimethylsilane, and isobutylmethyldimethoxysilane. The effect of polyethylene modification after chemical treatment was analyzed using surface tension measurement. The adhesive properties of Aeromonas hydrophila LOCK0968 were studied in water with a low concentration of organic compounds, using luminometric and microscopic methods, and the viability of the adhered bacterial cells was evaluated using the colony forming units method. After two-week incubation the chemically modified materials exhibited better antiadhesive and antibacterial characteristics in comparison to the native surface. Among the examined modifying agents, dimethoxydimethylsilane showed the best desired properties.

  4. Formation of giant crystalline grain via delayed growth process driven by organic molecular anisotropy

    NASA Astrophysics Data System (ADS)

    Al-Mahboob, A.; Fujikawa, Y.; Sadowski, J. T.; Hashizume, T.; Sakurai, T.

    2010-12-01

    The growth of (001)-oriented pentacene ( C22H14 , Pn) thin films on silicon surfaces has been extensively studied to elucidate the role of molecular anisotropy in nucleation and island evolution in organic film growth. In situ real-time low-energy electron microscopy studies of growth of Pn revealed a delayed, low-density nucleation that could be related to the difference in the orientation of this anisotropic molecule in its diffusing state and in the crystalline film. In contrast to the growth of Pn on self-assembled monolayers or SiO2 , we observed a delayed nucleation and formation of extraordinarily large grains (in submillimeter scale) on semiconducting α3-Bi-Si(111) and on semimetallic Bi(0001)/Si(111) with a continuation in film growth after stopping Pn deposition. The delayed and very low-density nucleation and continuing growth after stopping deposition could be explained by a incorporation-limited growth processes resulted from a large energy barrier for Pn nucleation in standing-up orientation, as the molecule needs to reorient itself from a lying-down, diffusing state in order to build into the crystalline film.

  5. Reduction, partial evaporation, and spattering - Possible chemical and physical processes in fluid drop chondrule formation

    NASA Technical Reports Server (NTRS)

    King, E. A.

    1983-01-01

    The major chemical differences between fluid drop chondrules and their probable parent materials may have resulted from the loss of volatiles such as S, H2O, Fe, and volatile siderophile elements by partial evaporation during the chondrule-forming process. Vertical access solar furnace experiments in vacuum and hydrogen have demonstrated such chemical fractionation trends using standard rock samples. The formation of immiscible iron droplets and spherules by in situ reduction of iron from silicate melt and the subsequent evaporation of the iron have been observed directly. During the time that the main sample bead is molten, many small spatter spherules are thrown off the main bead, thereby producing many additional chondrule-like melt spherules that cool rapidly and generate a population of spherules with size frequency distribution characteristics that closely approximate some populations of fluid drop chondrules in chondrites. It is possible that spatter-produced fluid drop chondrules dominate the meteoritic fluid drop chondrule populations. Such meteoritic chondrule populations should be chemically related by various relative amounts of iron and other volatile loss by vapor fractionation.

  6. Digital image database processing to simulate image formation in ideal lighting conditions of the human eye

    NASA Astrophysics Data System (ADS)

    Castañeda-Santos, Jessica; Santiago-Alvarado, Agustin; Cruz-Félix, Angel S.; Hernández-Méndez, Arturo

    2015-09-01

    The pupil size of the human eye has a large effect in the image quality due to inherent aberrations. Several studies have been performed to calculate its size relative to the luminance as well as considering other factors, i.e., age, size of the adapting field and mono and binocular vision. Moreover, ideal lighting conditions are known, but software suited to our specific requirements, low cost and low computational consumption, in order to simulate radiation adaptation and image formation in the retina with ideal lighting conditions has not yet been developed. In this work, a database is created consisting of 70 photographs corresponding to the same scene with a fixed target at different times of the day. By using this database, characteristics of the photographs are obtained by measuring the luminance average initial threshold value of each photograph by means of an image histogram. Also, we present the implementation of a digital filter for both, image processing on the threshold values of our database and generating output images with the threshold values reported for the human eye in ideal cases. Some potential applications for this kind of filters may be used in artificial vision systems.

  7. Formation and structure of stable aggregates in binary diffusion-limited cluster-cluster aggregation processes

    NASA Astrophysics Data System (ADS)

    López-López, J. M.; Moncho-Jordá, A.; Schmitt, A.; Hidalgo-Álvarez, R.

    2005-09-01

    Binary diffusion-limited cluster-cluster aggregation processes are studied as a function of the relative concentration of the two species. Both, short and long time behaviors are investigated by means of three-dimensional off-lattice Brownian Dynamics simulations. At short aggregation times, the validity of the Hogg-Healy-Fuerstenau approximation is shown. At long times, a single large cluster containing all initial particles is found to be formed when the relative concentration of the minority particles lies above a critical value. Below that value, stable aggregates remain in the system. These stable aggregates are composed by a few minority particles that are highly covered by majority ones. Our off-lattice simulations reveal a value of approximately 0.15 for the critical relative concentration. A qualitative explanation scheme for the formation and growth of the stable aggregates is developed. The simulations also explain the phenomenon of monomer discrimination that was observed recently in single cluster light scattering experiments.

  8. CO₂ processing and hydration of fruit and vegetable tissues by clathrate hydrate formation.

    PubMed

    Takeya, Satoshi; Nakano, Kohei; Thammawong, Manasikan; Umeda, Hiroki; Yoneyama, Akio; Takeda, Tohoru; Hyodo, Kazuyuki; Matsuo, Seiji

    2016-08-15

    CO2 hydrate can be used to preserve fresh fruits and vegetables, and its application could contribute to the processing of carbonated frozen food. We investigated water transformation in the frozen tissue of fresh grape samples upon CO2 treatment at 2-3 MPa and 3°C for up to 46 h. Frozen fresh bean, radish, eggplant and cucumber samples were also investigated for comparison. X-ray diffraction indicated that after undergoing CO2 treatment for several hours, structure I CO2 hydrate formed within the grape tissue. Phase-contrast X-ray imaging using the diffraction-enhanced imaging technique revealed the presence of CO2 hydrate within the intercellular spaces of these tissues. The carbonated produce became effervescent because of the dissociation of CO2 hydrate through the intercellular space, especially above the melting point of ice. In addition, suppressed metabolic activity resulting from CO2 hydrate formation, which inhibits water and nutrient transport through intercellular space, can be expected.

  9. Swelling related to ettringite crystal formation in chromite ore processing residue.

    PubMed

    Moon, Deok Hyun; Dermatas, Dimitris; Wazne, Mahmoud; Sanchez, Adriana M; Chrysochoou, Maria; Grubb, Dennis G

    2007-08-01

    Several million tons of Chromite Ore Processing Residue (COPR) were deposited at two sites in New Jersey and Maryland, USA, and over time they exhibited extensive heaving phenomena. Ettringite, a needle-shaped mineral and an expansive mineral commonly recognized in the literature concerning cement- and soil, has been identified extensively in numerous COPR samples collected from these sites. It was therefore believed that ettringite formation and its crystal growth are strongly associated with COPR heaving. We investigated the correlation between ettringite and the heaving phenomena in COPR materials that contained no initial ettringite. Two identical COPR samples were exposed to a 4% w/w sulfate solution (25 degrees C, 50 degrees C) in a confined swell test apparatus. Both swell test samples were analyzed by means of X-ray powder diffraction. The peak intensities of newly formed ettringite were more pronounced in the sample tested at 50 degrees C, and swell development was only observed in this sample. Scanning electron microscopy analyses revealed well-crystallized ettringite needles exceeding 40 microm in length for this sample, while ettringite crystals less than 15 microm in length formed in the sample tested at 25 degrees C. Therefore, the results suggest that the quantity of ettringite and the extent of crystallization play a key role in the heave of COPR.

  10. Investigation of TNB/NNAP cocrystal synthesis, molecular interaction and formation process

    NASA Astrophysics Data System (ADS)

    Chen, Peng-Yuan; Zhang, Lin; Zhu, Shun-Guan; Cheng, Guang-Bin; Li, Ning-Rui

    2017-01-01

    A novel cocrystal of 1,3,5-trinitrobenzene (TNB) and 1-nitronaphthalene (NNAP) was synthesized by solution and mechanochemical method, respectively. The crystal structure was characterized by single crystal X-ray diffraction (SXRD). Then the intermolecular interaction was illustrated quantitatively by Hirshfeld surface analysis accordingly. Two other isostructural cocrystals, TNT (2,4,6-trinitrotoluene)/NNAP and TNP (2,4,6-trinitrophenol)/NNAP were also calculated for comparison. Among the three cocrystals, TNB/NNAP cocrystal has the largest proportion of π-π stacking interaction (12.7%). While TNP/NNAP cocrystal has a greater percentage of hydrogen bonding than the other two cocrystals, which is 43.2% of the total interactions. These results indicate electronic effect has an influence on the intermolecular interaction in the cocrystal. The IR spectra of the intermediate products provide more information about the formation process of hydrogen bonding and π-π stacking. We can tell from the differential scanning calorimetry (DSC) thermograms that a eutectic mixture was generated first after TNB and NNAP were physically mixed without grinding, and then turned into the cocrystal and finally transformed completely.

  11. The Formation Process of Massive Close Spectroscopic Binaries: The Fission Hypothesis Revisited

    NASA Astrophysics Data System (ADS)

    Zinnecker, H.; Ostriker, J.

    2013-06-01

    The vast majority of massive Main-Sequence stars (M>20 Mo) seem to be born in close interactive binary systems (Chini et al. 2012, Sana et al. 2012). The very process by which these systems form is still a mystery and has received little attention so far. Because the binary separation is so tight (less than 1AU), break-up of a critically rotating protostar ("fission") remains an interesting possibility. However, standard current star formation theory treats fission as unlikely (cf. Tohline 2002, ARAA). We question this view and investigate minimum energy states of compressible polytropic analogs to the well-known incompressible MacLaurin spheroids. Dynamical non-axisymmetric instability at a critical ratio of rotational to gravitational energy (cf. Ostriker and Bodenheimer 1973) during the shrinkage of an accreting, rapidly rotating, bloated, massive protostar AFTER ACCRETION DECLINES may provide the conditions for break-up into a close binary system. Time dependent hydro-dynamical simulations are required to either confirm or reject this hypothesis.

  12. [Influencing Factors of Assimilable Organic Carbon (AOC) Formation in Drinking Water During Ozonation Process].

    PubMed

    Dong, Bing-zhi; Zhang, Jia-li; He, Chang

    2016-05-15

    The influences of ozone dosage, pH and ionic strength on the formation of Assimilable Organic Carbon (AOC) during ozonation were investigated. The result demonstrated that within the range of 1-5 mg · L⁻¹ O₃, the formation of AOC increased with increasing ozone dosage, but higher ozone dosage (9 mg · L⁻¹) resulted in reduction of AOC formation. AOC formation increased with higher pH but decreased with increasing ionic strength. The result also showed that AOC formation with hydrophobic fraction (HPO) was the most, followed by transphilic fraction (TPI), and charged hydrophilic fraction (CHPI), while neutral hydrophilic fraction (NHPI) was the least. It was found that AOC formation related closely with SUVA of small molecular weight organics, and the lower SUVA produced more AOC.

  13. Science Teachers' Representations of Classroom Practice in the Process of Formative Assessment Design

    NASA Astrophysics Data System (ADS)

    Heredia, Sara C.; Furtak, Erin Marie; Morrison, Deb; Renga, Ian Parker

    2016-11-01

    Formative assessment has been recognized as an essential element of effective classroom practice; as a result, teachers are increasingly required to create formative assessments for their classrooms. This study examines data drawn from a long-term, site-based professional development program that supported a department of biology teachers in the iterative design and enactment of common formative assessment tools. We analyze teacher conversations to understand how teachers collaborated to design formative assessments. Results indicate that when teachers attended to problems of practice related to teaching evolution, increased transparency in their talk helped build consensus about the design of formative assessment tools. These results highlight the importance of encouraging transparency in teacher dialog when they are engaged in collaborative design of formative assessments.

  14. Elucidation and control of biofilm formation processes in water treatment and distribution using the Unified Biofilm Approach.

    PubMed

    van der Kooij, D; Vrouwenvelder, J S; Veenendaal, H R

    2003-01-01

    Controlling biological processes in water treatment and distribution is a major challenge to water supply companies. In the Netherlands, the use of chlorine-based disinfectants in water treatment is limited as much as possible and treated water is distributed without disinfectant residual in most cases. Biofilm formation processes in water treatment and distribution are studied using adenosinetriphosphate (ATP) as the parameter for active biomass. ATP measurements are applied to assess biofilm concentrations in distribution systems, in the biofilm monitor to determine the biofilm formation rate of treated water, in the biomass production potential test to determine the effect of pipe materials on microbial growth and in membrane systems to quantify biofouling. The use of a single parameter enables to compare biofilm concentrations in all situations and contributes to the understanding and control of biofilm formation processes in water treatment and distribution. This approach has been designated as the Unified Biofilm Approach.

  15. In situ heat treatment of a tar sands formation after drive process treatment

    DOEpatents

    Vinegar, Harold J.; Stanecki, John

    2010-09-21

    A method for treating a tar sands formation includes providing a drive fluid to a hydrocarbon containing layer of the tar sands formation to mobilize at least some hydrocarbons in the layer. At least some first hydrocarbons from the layer are produced. Heat is provided to the layer from one or more heaters located in the formation. At least some second hydrocarbons are produced from the layer of the formation. The second hydrocarbons include at least some hydrocarbons that are upgraded compared to the first hydrocarbons produced by using the drive fluid.

  16. Sulfur barrier for use with in situ processes for treating formations

    DOEpatents

    Vinegar, Harold J.; Christensen, Del Scot

    2009-12-15

    Methods for forming a barrier around at least a portion of a treatment area in a subsurface formation are described herein. Sulfur may be introduced into one or more wellbores located inside a perimeter of a treatment area in the formation having a permeability of at least 0.1 darcy. At least some of the sulfur is allowed to move towards portions of the formation cooler than the melting point of sulfur to solidify the sulfur in the formation to form the barrier.

  17. Distributions, profiles and formation mechanisms of polychlorinated naphthalenes in cement kilns co-processing municipal waste incinerator fly ash.

    PubMed

    Liu, Guorui; Zhan, Jiayu; Zhao, Yuyang; Li, Li; Jiang, Xiaoxu; Fu, Jianjie; Li, Chunping; Zheng, Minghui

    2016-07-01

    Co-processing municipal solid waste incinerator (MSWI) fly ash in cement kilns is challenging because the unintentional production of persistent organic pollutants (POPs) during the process is not well understood. The distributions, profiles and formation mechanisms of polychlorinated naphthalenes (PCNs) as new POPs covered under Stockholm Convention in two cement kilns co-processing MSWI fly ash were studied. The average concentrations of PCNs in stack gas samples were 710 ng m(-3). The PCN concentration in particle samples collected from different process stages in the cement kilns ranged from 1.1 to 84.7 ng g(-1). Three process sites including suspension pre-heater boiler, humidifier tower, and the kiln back-end bag filter were identified to be the major formation sites of PCNs in cement kilns co-processing MSWI fly ash. The PCN distribution patterns were similar to that of polychlorinated dibenzo-p-dioxin and dibenzofuran (PCDD/Fs), which indicates the possibility for simultaneous control of PCNs and PCDD/Fs in cement kilns co-processing fly ash. Chlorination was suggested to be an important formation mechanism of PCNs, and chlorination pathways of PCN congeners are proposed based on the congener profiles. Thermodynamic calculations, including relative thermal energies (ΔE) and standard free energy of formation (ΔG), and the charge densities of the carbon atoms in PCN supported the proposed chlorination mechanisms for PCN formation. The results presented in this study might provide helpful information for developing techniques and strategies to control PCN emissions during cement kilns co-processing MSWI fly ash.

  18. CO2 + N2O mixture gas hydrate formation kinetics and effect of soil minerals on mixture-gas hydrate formation process

    NASA Astrophysics Data System (ADS)

    Enkh-Amgalan, T.; Kyung, D.; Lee, W.

    2012-12-01

    CO2 mitigation is one of the most pressing global scientific topics in last 30 years. Nitrous oxide (N2O) is one of the main greenhouse gases (GHGs) defined by the Kyoto Protocol and its global warming potential (GWP) of one metric ton is equivalent to 310 metric tons of CO2. They have similar physical and chemical properties and therefore, mixture-gas (50% CO2 + 50% N2O) hydrate formation process was studied experimentally and computationally. There were no significant research to reduce N20 gas and we tried to make hydrate to mitigate N20 and CO2 in same time. Mixture gas hydrate formation periods were approximately two times faster than pure N2O hydrate formation kinetic in general. The fastest induction time of mixture-gas hydrate formation observed in Illite and Quartz among various soil mineral suspensions. It was also observed that hydrate formation kinetic was faster with clay mineral suspensions such as Nontronite, Sphalerite and Montmorillonite. Temperature and pressure change were not significant on hydrate formation kinetic; however, induction time can be significantly affected by various chemical species forming under the different suspension pHs. The distribution of chemical species in each mineral suspension was estimated by a chemical equilibrium model, PHREEQC, and used for the identification of hydrate formation characteristics in the suspensions. With the experimental limitations, a study on the molecular scale modeling has a great importance for the prediction of phase behavior of the gas hydrates. We have also performed molecular dynamics computer simulations on N2O and CO2 hydrate structures to estimate the residual free energy of two-phase (hydrate cage and guest molecule) at three different temperature ranges of 260K, 273K, and 280K. The calculation result implies that N2O hydrates are thermodynamically stable at real-world gas hydrate existing condition within given temperature and pressure. This phenomenon proves that mixture-gas could be

  19. Geologically Controlled Isotope-Time Patterns Reveal Early Differentiation and Crust Formation Processes

    NASA Astrophysics Data System (ADS)

    Bennett, V. C.; Nutman, A. P.

    2014-12-01

    The mechanisms of continental crust production and evolution in the early Earth remain controversial, as are questions of the relative roles of early differentiation versus subsequent tectonic procssing in creating Earth's chemical signatures. Here we present geologic observations integrated with whole rock major, trace element and Sm-Nd isotopic signatures and combined with U-Pb and Lu-Hf isotopic compositions of zircon populations from the same rocks, from the most extensive early rock record comprising the 3.9 Ga to 3.6 Ga terranes of southwest Greenland. These data reveal repeated patterns of formation of juvenile TTG crust and associated mafic and ultramafic rocks in convergent margin settings followed by formation of more evolved granites [1]. Our new zircon Lu-Hf data from rare 3.6-3.7 Ga tonalites within the Itsaq Gneiss Complex, obtained from single component, non-migmatitic gneisses with simple zircon populations, limited within sample Hf isotopic variability and accurate U-Pb ages, now document extraction of juvenile tonalites from a near chondritic mantle source between 3.9 Ga and 3.6 Ga. The more evolved, granitic rocks in each area show slightly negative initial ɛHf in accord with crustal reworking of the older (3.8-3.9 Ga) gniesses. There is no evidence for Hadean material in the sources of the granitoids. The Hf isotope-time patterns are consistent with juvenile crust production from a mantle source that experienced only modest amounts of prior crustal extraction. They are distinct from those predicted by reprocessing of an enriched Hadean mafic crust, as has been proposed for this region [2] and for the source of the Hadean Jack Hills zircons [3]. The well-documented, time decreasing, positive 142Nd anomalies [e.g., 4] from these rocks are further evidence of crustal derivation from a convecting mantle source, rather than reworking of an enriched mafic lithosphere. The 143Nd isotopic -time patterns are more complex, reflecting the interplay

  20. Impact cratering as a major process in planet formation: Projectile identification of meteorite craters

    NASA Astrophysics Data System (ADS)

    Schmidt, G.; Kratz, K.

    2009-12-01

    Ancient surfaces of solid planets show that impact cratering is a major process in planet formation. Understanding origin and influence of impactors on the chemical composition of planets (core, mantle and crust) it is important to know the relative abundances of highly siderophile elements (Os, Ir, Ru, Pt, Rh, Pd) in the silicate mantle and crust of planets and meteorites. Refractory highly siderophile elements, such as Os and Ir, are abundant in most meteorites but depleted in crustal rocks (low target/meteorite ratios) and thus the most reliable elements for projectile identification. However, target/meteorite ratios are high if target rocks consist of mantle rocks. In such cases elements are enriched in impactites due to relatively high abundances (ng/g level) in target rocks to make the identification of projectile types difficult (e.g., Gardnos impact structure in Norway). The Ru/Ir ratio is the most reliable key ratio that rules out Earth primitive upper mantle (PUM) derived refractory highly siderophile element components in impactites. The well established Ru/Ir ratio of the Earth mantle of 2.0 ± 0.1 (e.g. Schmidt and Kratz 2004) is significantly above the chondritic ratios varying from 1.4 to 1.6. On Earth Rh/Ir, Ru/Ir, Pd/Ir, and Pt/Os derived from PUM match the ratios of group IV irons with fractionated trace element patterns. The question raise if HSE in mantle rocks are added to the accreting Earth by a late bombardment of pre-differentiated objects or the cores of these objects (magmatic iron meteorites as remnants of the first planetesimals, e.g. Kleine et al. 2009) or some unsampled inner solar system materials from the Mercury-Venus formation region, not sampled through meteorite collections (Schmidt 2009). The PGE and Ni systematics of the upper continental crust (UCC) closely resembles group IIIAB iron meteorites with highly fractionated refractory trace element patterns, pallasites, and the evolved suite of Martian meteorites (representing

  1. Using a paleo perspective to decipher climate controls on erosion and landscape evolution

    NASA Astrophysics Data System (ADS)

    Roering, J. J.; Marshall, J. A.; Granger, D. E.; Fox, M.; Gavin, D. G.; White, L. W.

    2015-12-01

    Today, topographic, erosion, and climate data are measured in abundance but the role of climate in modulating sediment production and landscape evolution remains difficult to characterize. Studies that quantify climate controls on denudation by analyzing multiple study areas with varying temperature and precipitation are hampered by site-to-site variations in topography, substrate, and vegetation, as well as uncertainty in the state of landscape adjustment. Alternatively, sedimentary records at a given location provide a means to track how climate variations influence sediment flux and weathering rates and mechanisms. Cosmogenic nuclide concentrations in well-dated sediment cores provide a means to quantify how erosion rates track climate, particularly orbital (or Milankovitch), fluctuations. Most cosmogenic analyses of erosion assume steady exhumation. By contrast, time-varying cosmogenic concentrations at a given location require a systematic inverse analysis of inheritance to decipher actual erosion rate changes that integrate in observed cosmogenic concentrations. Failure to consider transient erosion results in biased interpretations of paleo-erosion datasets. Here, we use a suite of inverse methods to constrain erosion rates through the last 50kya at our forested, steepland field site in western Oregon where Last Glacial Maximum (LGM) erosion rates are observed to be 2.5x faster than modern rates. Both paleoclimate simulations and paleovegetation data indicate colder and drier conditions during the LGM across our study domain, such that temperature, rather than precipitation, may be the dominant driver of geomorphic processes during glacial intervals in many mid-latitude regions. Other climate dependencies will apply elsewhere, but the coupling of process theory and climate reconstructions with well-characterized sedimentary records will help resolve the enigmatic role of climate fluctuations.

  2. Unpacking the Formative Assessment Processes of Secondary Mathematics Teachers Who Use Wireless Networked Classroom Technology

    ERIC Educational Resources Information Center

    Roble, Amanda Jean

    2015-01-01

    The use of formative assessment can increase student achievement (Black & Wiliam, 1998a). However, some of the challenges of incorporating formative assessment into instruction include the length of time needed to collect, assess and provide feedback to all students and dealing with students misunderstandings and incorrect answers that are…

  3. Wax barrier for use with in situ processes for treating formations

    DOEpatents

    Vinegar, Harold J.; Carter, Ernest E.; Son, Jaime Santos; Bai, Taixu; Khoda Verdian, Mohamad Fereydoon

    2010-04-27

    Methods for forming a barrier around at least a portion of a treatment area in a subsurface formation are described herein. A material including wax may be introduced into one or more wellbores. The material introduced into two or more wells may mix in the formation and congeal to form a barrier to fluid flow.

  4. Science Teachers' Representations of Classroom Practice in the Process of Formative Assessment Design

    ERIC Educational Resources Information Center

    Heredia, Sara C.; Furtak, Erin Marie; Morrison, Deb; Renga, Ian Parker

    2016-01-01

    Formative assessment has been recognized as an essential element of effective classroom practice; as a result, teachers are increasingly required to create formative assessments for their classrooms. This study examines data drawn from a long-term, site-based professional development program that supported a department of biology teachers in the…

  5. Investigation of the Formation Process of Two Piracetam Cocrystals during Grinding.

    PubMed

    Rehder, Sönke; Klukkert, Marten; Löbmann, Korbinian A M; Strachan, Clare J; Sakmann, Albrecht; Gordon, Keith; Rades, Thomas; Leopold, Claudia S

    2011-10-12

    Cocrystal formation rates during dry grinding and liquid-assisted grinding were investigated by X-ray powder diffractometry and Raman spectroscopy. Two polymorphic forms of piracetam were used to prepare known piracetam cocrystals as model substances, i.e.,piracetam-citric acid and piracetam-tartaric acid cocrystals. Raman spectroscopy in combination with principal component analysis was used to visualize the cocrystal formation pathways. During dry grinding, cocrystal formation appeared to progress via an amorphous intermediate stage, which was more evident for the piracetam-citric acid than for the piracetam-tartaric acid cocrystal. It was shown that liquid-assisted grinding led to faster cocrystal formation than dry grinding, which may be explained by the higher transformation rate due to the presence of liquid. The cocrystal formation rate did not depend on the applied polymorphic form of the piracetam and no polymorphic cocrystals were obtained.

  6. Formation and dissolution processes of the 6-thioguanine (6TG) self-assembled monolayer. A kinetic study.

    PubMed

    Madueño, Rafael; Pineda, Teresa; Sevilla, José Manuel; Blázquez, Manuel

    2005-02-03

    This is a report on the kinetics of the destruction and formation processes of the 6-thioguanine self-assembled monolayer (6TG SAM) on a mercury electrode from acid solutions by chronoamperometry. The destruction of the 6TG SAM that has been previously formed under open circuit potential conditions is carried out by stepping the potential from an initial value where the chemisorbed layer is stable up to potentials where the molecules are no longer chemisorbed. The destruction of the SAM has been described by a model that involves three types of contributions: (i) a Langmuir-type adsorption process, (ii) a 2D nucleation mechanism followed by a growth controlled by surface diffusion, and (iii) a 2D nucleation mechanism followed by a growth at a constant rate. The nonlinear fit of the experimental transients by using this procedure allows the quantitative determination of the individual contributions to the overall process. The kinetics of the formation process is studied under electrochemical conditions. The chronoamperometric experiment allows us to monitor the early stages of 6TG SAM formation. The implications of the physisorbed state at low potentials in the type of monolayer formation and destruction processes as well as the influence of temperature are also discussed.

  7. Interspecies interactions result in enhanced biofilm formation by co-cultures of bacteria isolated from a food processing environment.

    PubMed

    Røder, Henriette L; Raghupathi, Prem K; Herschend, Jakob; Brejnrod, Asker; Knøchel, Susanne; Sørensen, Søren J; Burmølle, Mette

    2015-10-01

    Bacterial attachment and biofilm formation can lead to poor hygienic conditions in food processing environments. Furthermore, interactions between different bacteria may induce or promote biofilm formation. In this study, we isolated and identified a total of 687 bacterial strains from seven different locations in a meat processing environment and evaluated their biofilm formation capability. A diverse group of bacteria was isolated and most were classified as poor biofilm producers in a Calgary biofilm device assay. Isolates from two sampling sites, the wall and the meat chopper, were further examined for multispecies biofilm formation. Eight strains from each sampling site were chosen and all possible combinations of four member co-cultures were tested for enhanced biofilm formation at 15 °C and 24 °C. In approximately 20% of the multispecies consortia grown at 15 °C, the biofilm formation was enhanced when comparing to monospecies biofilms. Two specific isolates (one from each location) were found to be present in synergistic combinations with higher frequencies than the remaining isolates tested. This data provides insights into the ability of co-localized isolates to influence co-culture biofilm production with high relevance for food safety and food production facilities.

  8. Holocene loess deposition and soil formation as competing processes, Matanuska Valley, southern Alaska

    USGS Publications Warehouse

    Muhs, D.R.; McGeehin, J.P.; Beann, J.; Fisher, E.

    2004-01-01

    Although loess-paleosol sequences are among the most important records of Quaternary climate change and past dust deposition cycles, few modern examples of such sedimentation systems have been studied. Stratigraphic studies and 22 new accelerator mass spectrometry radiocarbon ages from the Matanuska Valley in southern Alaska show that loess deposition there began sometime after ???6500 14C yr B.P. and has continued to the present. The silts are produced through grinding by the Matanuska and Knik glaciers, deposited as outwash, entrained by strong winds, and redeposited as loess. Over a downwind distance of ???40 km, loess thickness, sand content, and sand-plus-coarse-silt content decrease, whereas fine-silt content increases. Loess deposition was episodic, as shown by the presence of paleosols, at distances >10 km from the outwash plain loess source. Stratigraphic complexity is at a maximum (i.e., the greatest number of loesses and paleosols) at intermediate (10-25 km) distances from the loess source. Surface soils increase in degree of development with distance downwind from the source, where sedimentation rates are lower. Proximal soils are Entisols or Inceptisols, whereas distal soils are Spodosols. Ratios of mobile CaO, K2O, and Fe2O3 to immobile TiO2 show decreases in surface horizons with distance from the source. Thus, as in China, where loess deposition also takes place today, eolian sedimentation and soil formation are competing processes. Study of loess and paleosols in southern Alaska shows that particle size can vary over short distances, loess deposition can be episodic over limited time intervals, and soils developed in stabilized loess can show considerable variability under the same vegetation. ?? 2004 University of Washington. All rights reserved.

  9. Theoretical study of nanoparticle formation in thermal plasma processing: Nucleation, coagulation and aggregation

    NASA Astrophysics Data System (ADS)

    Mendoza Gonzalez, Norma Yadira

    This work presents a mathematical modeling study of the synthesis of nanoparticles in radio frequency (RF) inductively coupled plasma (ICP) reactors. The purpose is to further investigate the influence of process parameters on the final size and morphology of produced particles. The proposed model involves the calculation of flow and temperature fields of the plasma gas. Evaporation of raw particles is also accounted with the particle trajectory and temperature history calculated with a Lagrangian approach. The nanoparticle formation is considered by homogeneous nucleation and the growth is caused by condensation and Brownian coagulation. The growth of fractal aggregates is considered by introducing a power law exponent Df. Transport of nanoparticles occurs by convection, thermophoresis and Brownian diffusion. The method of moments is used to solve the particle dynamics equation. The model is validated using experimental results from plasma reactors at laboratory scale. The results are presented in the following manner. First, use is made of the computational fluid dynamics software (CFD), Fluent 6.1 with a commercial companion package specifically developped for aerosols named: Fine Particle Model (FPM). This package is used to study the relationship between the operating parameters effect and the properties of the end products at the laboratory scale. Secondly, a coupled hybrid model for the synthesis of spherical particles and fractal aggregates is developped in place of the FPM package. Results obtained from this model will allow to identify the importance of each parameter in defining the morphology of spherical primary particles and fractal aggregates of nanoparticles. The solution of the model was made using the geometries and operating conditions of existing reactors at the Centre de Recherche en Energie, Plasma et Electrochimie (CREPE) of the Universite de Sherbrooke, for which experimental results were obtained experimentally. Additionally, this study

  10. Gap formation processes in a high-density plasma opening switch

    NASA Astrophysics Data System (ADS)

    Grossmann, J. M.; Swanekamp, S. B.; Ottinger, P. F.; Commisso, R. J.; Hinshelwood, D. D.; Weber, B. V.

    1995-01-01

    A gap opening process in plasma opening switches (POS) is examined with the aid of numerical simulations. In these simulations, a high density (ne=1014-5×1015 cm-3) uniform plasma initially bridges a small section of the coaxial transmission line of an inductive energy storage generator. A short section of vacuum transmission line connects the POS to a short circuit load. The results presented here extend previous simulations in the ne=1012-1013 cm-3 density regime. The simulations show that a two-dimensional (2-D) sheath forms in the plasma near a cathode. This sheath is positively charged, and electrostatic sheath potentials that are large compared to the anode-cathode voltage develop. Initially, the 2-D sheath is located at the generator edge of the plasma. As ions are accelerated out of the sheath, it retains its original 2-D structure, but migrates axially toward the load creating a magnetically insulated gap in its wake. When the sheath reaches the load edge of the POS, the POS stops conducting current and the load current increases rapidly. At the end of the conduction phase a gap exists in the POS whose size is determined by the radial dimensions of the 2-D sheath. Simulations at various plasma densities and current levels show that the radial size of the gap scales roughly as B/ne, where B is the magnetic field. The results of this work are discussed in the context of long-conduction-time POS physics, but exhibit the same physical gap formation mechanisms as earlier lower density simulations more relevant to short-conduction-time POS.

  11. Land-Ocean Difference of the Warm Rain Formation Process in Satellite Observations, Ground-Based Observations, and Model Simulations

    NASA Astrophysics Data System (ADS)

    Takahashi, H.; Suzuki, K.; Stephens, G. L.

    2015-12-01

    This study examines the difference in the warm rain formation process between over land and over ocean using a combination of CloudSat and Moderate Resolution Imaging Spectroradiometer (MODIS) observations. Previous studies (Nakajima et al. 2010; Suzuki et al. 2010) have devised a novel methodology for combining the CloudSat and MODIS satellite observations to investigate the microphysical processes. The statistics constructed with the methodology, referred to as the Contoured Frequency by Optical Depth Diagram (CFODD), provides a lifecycle view of warm clouds. Following the previous studies, we conduct detailed analyses of CFODD with a particular focus on comparisons between land and ocean. Our result shows that the coalescence process starts faster in the oceanic warm clouds than continental warm clouds. Also, oceanic clouds tend to produce more drizzle than continental clouds. Moreover, it is found that the difference between oceanic and continental cloud-to-precipitation process can be explained by different environmental conditions. For example, the cloud-to-precipitation processes in continental clouds are more similar to those in oceanic clouds over unstable environments than those over stable environments. Furthermore, ground-based measurement data obtained from Atmospheric Radiation Measurement (ARM) data and a cloud model simulation are analyzed to test how vertical velocity affects the warm rain formation process. Our result suggests that although the intensities of convective updrafts in warm clouds have been paid less attention, intensities of convective updrafts play a critical role in the warm rain formation process.

  12. Processes and fluxes during the initial stage of acid sulfate soil formation

    NASA Astrophysics Data System (ADS)

    Gröger, J.; Hamer, K.; Schulz, H. D.

    2009-04-01

    Acid sulfate soils occur over a wide range of climatic zones, mainly in coastal landscapes. In these soils, the release of sulfuric acid by the oxidation of pyrite generates a very acidic environment (e.g., DENT and PONS, 1995, PONS, 1973). Two major types of acid sulfate soils can be distinguished: In actual acid sulfate soils, the initially contained pyrite was at least partly oxidized. This resulted in a severe acidification of the soil. Potential acid sulfate soils are generally unoxidized and contain large amounts of pyrite. Upon oxidation, these soils will turn into actual acid sulfate soils. By excavation or lowering of the groundwater table, potential acid sulfate soils can be exposed to atmospheric oxygen. During oxidation the pH drops sharply to values below pH 4. This acidification promotes the release of various metals, e.g., alumina, iron and heavy metals. Additionally, large quantities of sulfate are released. In order to assess the effects of disturbances of potential acid sulfate soils, for example by excavations during construction works, several large scale column experiments were conducted with various types of potential acid sulfate soils from Northern Germany. In these experiments, the oxidation and initial profile development of pyritic fen peats and thionic fluvisols were studied over a period of 14 months. The study focused on leaching and the translocation of various metals in the soil profile. To study mobilization processes, element fluxes and the progress of acidification, soil water and leachate were analyzed for total element concentrations. Furthermore, several redox-sensitive parameters, e.g., Fe2+ and sulfide, were measured and changes to the initial solid phase composition were analyzed. Chemical equilibria calculations of the soil water were used to gain insights into precipitation processes of secondary products of pyrite oxidation and leaching products. The results of this study will support the assessment of risks deriving from

  13. A possible formation process of outer lobes of Double Layered Ejecta craters on Mars

    NASA Astrophysics Data System (ADS)

    Suzuki, A.; Baratoux, D.; Kurita, K.

    2008-12-01

    Martian impact ejecta are famous for their morphologies suggesting ejecta would be formed by radial ground- hugging flows in the late stage of the impact. The atmosphere [Schultz, 1992] and/or the subsurface volatiles [Carr et al., 1977] have been suggested as causes of fluidization. Examining the process to generate and emplace the radial flow would allow us to understand the nature of the entrained fluid. Double Layered Ejecta (DLE), one of the major subclasses of martian ejecta, have many unique features. Most enigmatic is the presence of two distinct layers of ejecta: a thick inner lobe and a thin outer lobe. The striking differences between the two lobes suggest that two different processes occur independently during ejecta emplacement, a case implausible by a single ballistic trajectory. In this study, based on the hypothesis that an impact- induced vortex ring modifies surface materials in the late stage of the impact to produce the outer lobe, the volumes of displaced particles by the vortex ring were measured in laboratory experiments to compare the volumes of the outer lobes. We utilized the experimental situation of a vortex ring impacting on a particle layer. Two dimensionless numbers based on particle size (Shields' and Reynolds number) in lab fall within the same ranges as those on Mars [Suzuki et al., 2007], it is thus possible to compare the relationships between volumes and Γ, a parameter expressing the strength of a vortex ring. We fit the dependence of Vdisplaced on Gamma using a power law Vdisplaced = a Γb and we found b = 1.25 ± 0.17. The volumes of the outer lobes were measured, selecting 7 fresh craters larger than 5km in diameter in the survey area (0N-60N, 90E-150E). In the case of impact cratering, the vortex strength Γ can be scaled with the crater diameter [Barnouin-Jha and Schultz, 1998] as Γ ∝ D⅔. Using also a power law Vouter = c Γd, we obtained d = 1.42 ± 0.24 for the volume of outer lobes of DLE. As the power indices of

  14. The Earth's core formation and development: evidence from evolution of tectonomagmatic processes and paleomagnetic data

    NASA Astrophysics Data System (ADS)

    Sharkov, E. V.

    2011-12-01

    Many geologists confident that the core provides modern tectonic and magmatic activity on the Earth, which explains our interest in this topic, and vice versa we can use evolution of tectonomagmatic processes throughout the Earth's (and other terrestrial planetary bodies) history for reconstruction of the core formation and evolution. Most researchers, follow to V. Safronov (1972) and A. Ringwood (1979), confident that the Earth has occurred due to accumulation of hypothetical chemically homogeneous planetesimals, composed by chondrite material, ie, as a result of homogeneous accretion. However, this single-stage chondrite model of accretion is inconsistent with fact of cardinal change of tectonomagmatic processes on the terrestrial planets in the middle stages of their development. For example, the critical irreversible change of the Earth's tectonomagmatic evolution occurred in range 2.35-2.0 Ga, when geochemical-enriched Fe-Ti picrites and basalts firstly appeared in large quantities and first geological evidence of plate tectonics showed up (Sharkov, Bogatikov, 2010). We suggest that these changes were linked with ascending of mantle superplumes of the second generation (thermochemical), originated at the the boundary of liquid iron core and silicate mantle, in similar way as the modern plumes. All terrestrial planetary bodies (Earth, Venus, Mars, Mercury, and the Moon) have a similar structure, consist of iron core and silicate envelope, and developed at the same scenario, which provide for drastic irreversible change in character of tectonomagmatic processes at the middle stages of their evolution (Sharkov, Bogatikov, 2009). Such a situation can be realized only in case: (1) the terrestrial planetary bodies originally had heterogeneous structure, and (2) their heating occurred from the top down accompanied by cooling of outer shells. As a result, material of the primordial cores, where enriched material survived, were remained a long time untouched. It

  15. Inhibition of clot formation in deterministic lateral displacement arrays for processing large volumes of blood for rare cell capture.

    PubMed

    D'Silva, Joseph; Austin, Robert H; Sturm, James C

    2015-05-21

    Microfluidic deterministic lateral displacement (DLD) arrays have been applied for fractionation and analysis of cells in quantities of ~100 μL of blood, with processing of larger quantities limited by clogging in the chip. In this paper, we (i) demonstrate that this clogging phenomenon is due to conventional platelet-driven clot formation, (ii) identify and inhibit the two dominant biological mechanisms driving this process, and (iii) characterize how further reductions in clot formation can be achieved through higher flow rates and blood dilution. Following from these three advances, we demonstrate processing of 14 mL equivalent volume of undiluted whole blood through a single DLD array in 38 minutes to harvest PC3 cancer cells with ~86% yield. It is possible to fit more than 10 such DLD arrays on a single chip, which would then provide the capability to process well over 100 mL of undiluted whole blood on a single chip in less than one hour.

  16. Peat formation processes through the millennia in tidal marshes of the Sacramento-San Joaquin Delta, California, USA

    USGS Publications Warehouse

    Drexler, Judith Z.

    2011-01-01

    The purpose of this study was to determine peat formation processes throughout the millennia in four tidal marshes in the Sacramento-San Joaquin Delta. Peat cores collected at each site were analyzed for bulk density, loss on ignition, and percent organic carbon. Core data and spline fit age-depth models were used to estimate inorganic sedimentation, organic accumulation, and carbon sequestration rates in the marshes. Bulk density and percent organic matter content of peat fluctuated through time at all sites, suggesting that peat formation processes are dynamic and responsive to watershed conditions. The balance between inorganic sedimentation and organic accumulation at the sites also varied through time, indicating that marshes may rely more strongly on either norganic or organic matter for peat formation at particular times in their existence. Mean carbon sequestration rates found in this study (0.38-0.79 Mg C ha-1 year-1) were similar to other long-term estimates for temperate peatlands.

  17. A Theoretical Approach to the Organizational Knowledge Formation Process: Integrating the Concepts of Individual Learning and Learning Organization Culture

    ERIC Educational Resources Information Center

    Song, Ji Hoon; Chermack, Thomas J.

    2008-01-01

    The purpose of this article is to examine the link between individual learning processes and continuous organizational knowledge formation through an integrated literature review of these perspectives from both academic and practical viewpoints. In the current fierce economic environment, individual knowledge is regarded as the most valuable asset…

  18. Formative, Process, and Intermediate Outcome Evaluation of a Pilot School-based 5 A Day for Better Health Project.

    ERIC Educational Resources Information Center

    Harris, Kari Jo; Richter, Kimber P.; Schultz, Jerry; Johnston, Judy

    1998-01-01

    Examines formative, process, and intermediate outcome results of a school-based project linked to the National 5 A Day for Better Health campaign to increase fruit and vegetable consumption. Three elementary schools conducted the local campaign. Activity logs, redeemed coupons, and focus groups indicated that the project was implemented as planned…

  19. Laser transmission welding of ABS: Effect of CNTs concentration and process parameters on material integrity and weld formation

    NASA Astrophysics Data System (ADS)

    Rodríguez-Vidal, E.; Quintana, I.; Gadea, C.

    2014-04-01

    This paper reports a study of the laser transmission welding of polymeric joints composed by two ABS (acrylonitrile/butadiene/styrene) sheets, one transparent (natural ABS) and the other absorbent (filled by different percentages of carbon nanotubes (CNTs)). The objective of this work is to analyze the effect of process parameters and CNTs concentrations on weld formation and mechanical resistance of the weld joints.

  20. Lessons Learnt from Applying Action Research to Support Strategy Formation Processes in Long-Term Care Networks

    ERIC Educational Resources Information Center

    Cramer, Hendrik; Dewulf, Geert; Voordijk, Hans

    2015-01-01

    This study demonstrates how action research (AR) that is aimed at scaling-up experiments can be applied to support a strategy formation process (SFP) in a subsidized long-term care network. Previous research has developed numerous AR frameworks to support experiments in various domains, but has failed to explain how to apply AR and action learning…

  1. Formation of Research Competence of the Future Elementary School Teachers--In the Process of Professional Training

    ERIC Educational Resources Information Center

    Syzdykbayeva, Aigul Dzhumanazarovna; Bainazarova, Tursynay Beysembekovna; Aitzhanova, Elmira Nyrmahankyzy

    2015-01-01

    The present article presents the structural-functional model of formation of research competence of future elementary school teachers in the process of professional training. This model includes a set of interrelated and interdependent structural components: target; informative; procedural; estimate-effective structural components. The article…

  2. Processes of Formation of Spheroidal Concretions and Inferences for "Blueberries" in Meridiani Planum Sediments

    NASA Astrophysics Data System (ADS)

    Coleman, M. L.

    2005-03-01

    Formation of spheroidal concretions on Earth results generally from reactions of organic matter in oxidized sediments. Had organic matter been present in Merididani Planum it could have produced a reduced iron mineral phase later oxidized to hematite.

  3. Kinetics of elementary processes relevant to incipient soot formation. Final technical report

    SciTech Connect

    Lin, M.C.

    1998-03-09

    In order to better understand the mechanism of soot formation (one of the most challenging problems in the study of hydrocarbon combustion chemistry), reliable rate constants for the key reaction steps involved in the formation and polymerization of aromatic hydrocarbons in the inception stage are required for kinetic modeling. In this DOE sponsored work, the authors have developed three new experimental methods: cavity ring-down (CRD) spectrometry, pyrolysis/Fourier transform infrared spectrometry (p/FTIRS) and pulsed laser photolysis/mass spectrometry (PLP/MS) for kinetic measurements of C{sub 6}H{sub 5} reactions pivotal to incipient soot formation chemistry. In addition, the authors have also carried out ab initio molecular orbital (MO) calculations for several key elementary combustion reactions relevant to soot formation. The results are briefly summarized in the report using selected examples for more detailed discussion. 84 refs.

  4. In situ conversion process systems utilizing wellbores in at least two regions of a formation

    DOEpatents

    Vinegar, Harold J.; Hsu, Chia-Fu

    2011-09-27

    A system for heating a subsurface formation is described. The system includes a plurality of elongated heaters located in a plurality of openings in the formation. At least two of the heaters are substantially parallel to each other for at least a portion of the lengths of the heaters. At least two of the heaters have first end portions in a first region of the formation and second end portions in a second region of the formation. A source of time-varying current is configured to apply time-varying current to at least two of the heaters. The first end portions of at least two heaters are configured to have substantially the same voltage applied to them. The second portions of at least two heaters are configured to have substantially the same voltage applied to them.

  5. Deuteration and evolution in the massive star formation process. The role of surface chemistry

    NASA Astrophysics Data System (ADS)

    Fontani, F.; Busquet, G.; Palau, Aina; Caselli, P.; Sánchez-Monge, Á.; Tan, J. C.; Audard, M.

    2015-03-01

    Context. An ever growing number of observational and theoretical evidence suggests that the deuterated fraction (column density ratio between a species containing D and its hydrogenated counterpart, Dfrac) is an evolutionary indicator both in the low- and the high-mass star formation process. However, the role of surface chemistry in these studies has not been quantified from an observational point of view. Aims: Because many abundant species, such as NH3, H2CO, and CH3OH, are actively produced on ice mantles of dust grains during the early cold phases, their Dfrac is expected to evolve differently from species formed only (or predominantly) in the gas, such as N2H+, HNC, HCN, and their deuterated isotopologues. The differences are expected to be relevant especially after the protostellar birth, in which the temperature rises, causing the evaporation of ice mantles. Methods: To compare how the deuterated fractions of species formed only in the gas and partially or uniquely on grain surfaces evolve with time, we observed rotational transitions of CH3OH, 13CH3OH, CH2DOH, and CH3OD at 3 mm and 1.3 mm, of NH2D at 3 mm with the IRAM-30 m telescope, and the inversion transitions (1, 1) and (2, 2) of NH3 with the GBT, towards most of the cores already observed in N2H+, N2D+, HNC, and DNC. Results: NH2D is detected in all but two cores, regardless of the evolutionary stage. Dfrac(NH3) is on average above 0.1 and does not change significantly from the earliest to the most evolved phases, although the highest average value is found in the protostellar phase (~0.3). Few lines of CH2DOH and CH3OD are clearly detected, and then only towards protostellar cores or externally heated starless cores. In quiescent starless cores, we have only one doubtful detection of CH2DOH. Conclusions: This work clearly confirms an expected different evolutionary trend of the species formed exclusively in the gas (N2D+ and N2H+) and those formed partially (NH2D and NH3) or totally (CH2DOH and CH3

  6. Dynamic processes in the lithosphere leading to extension, rifting and basin formation

    NASA Astrophysics Data System (ADS)

    Anderson, Thomas

    2014-05-01

    The similarity of ages of extensional core complexes, co-genetic basin formation, and kinematically compatible movements along large strike-slip faults in western North America to ages of comparable events within the Himalayas-Alps orogenic belt leads to the speculation that strain related to changes in Pacific (PAC)-North America(NA) plate motions may be recorded on a global scale affecting the coupled plates and extending eastward across Eurasia. The contemporaneous global deformation reflects abrupt changes in PAC-NA plate motions in response to coupling following convergence of buoyant oceanic lithosphere, commonly part of a spreading center, which impedes subduction and leads to collision followed by coupling when the buoyant lithosphere binds against the base of the overriding continental plate. Critical coupling of a sufficiently long ridge segment leads to "capture", after which the former movements of the newly coupled plates are integrated abruptly and changed from previous directions. In western North America, episodes of capture of the NA plate by the (PAC) plate are recorded by break-up unconformities (ca. 55, 35, and 17 Ma) and basins commonly within extensional domains distinguished by age and direction of tectonic transport (Eocene [~55-42 Ma], ca. 285o, Oligocene [~35-20 Ma], 240o, Miocene [17-0 Ma], ca. 280o). The transport directions record the integration of the southwesterly motion of NA , related to mantle convection, and the northwesterly motion of PAC, driven by slab pull. Following each coupling event, PAC moves westward dragging: 1) the formerly subducting Farallon slab, 2) the coupled, formerly overriding, NA plate, and 3) Eurasia (EA), with it. In response to the strong extension that is imposed upon rocks within domains encompassed by the PAC-NA coupled region, and along the southern margin of Eurasia, brittle deformation, accommodated by normal and strike-slip faults, and formation of contemporaneous basins, takes place. Core

  7. [Distinguishing normal identity formation process for sexual minorities from obsessive compulsive disorder with sexual orientation obsessions].

    PubMed

    Igartua, Karine J

    2015-01-01

    Objectives In synthesizing a homosexual or bisexual identity, an individual may go through different stages before coming to a positive healthy identity. It is likely that there will be a period in which homosexual yearnings will be unwanted. Sometimes this distress leads the person to consult a health professional. Conversion therapy has been proven both ineffective and harmful and therefore has been ethically prohibited by all major psychiatric and psychological associations. The responsible clinician will attempt to assist the individual in his acceptance of his sexual minority. Occasionally individuals without homoeroticism consult because of distress related to sexual identity questioning which poses a different problem for clinicians especially if the situation goes unrecognized. The objective of this paper is to describe homosexual obsessive compulsive disorder (HOCD) and distinguish it clinically from the normal process of sexual minority identity formation in western culture.Methods A literature review yielded very few descriptions of homosexual OCD. A retrospective chart review of all patients seen in the last 3 years at the McGill University Sexual Identity Centre was conducted to identify all the cases of OCD. Six cases were found, 4 of which were of HOCD and are presented. Similarities between cases are highlighted.Results All cases were young men with relatively little relationship and sexual experience. Most were rather shy and had some other obsessional history in the past though often at a sub-clinical threshold. Obsessional doubt about their orientation was very distressing and did not abate over time as would normally occur with a homoerotic individual. The four patients who had an obsession of being gay despite little or no homoerotism are presented in detail. They all presented mental compulsions, avoidance and physiological monitoring. Continuous internal debate trying to prove or disprove sexual orientation was a ubiquitous mental

  8. Formation processes of floe size distribution in the marginal ice zone (Invited)

    NASA Astrophysics Data System (ADS)

    Toyota, T.; Kohout, A.; Fraser, A.

    2013-12-01

    Since the marginal ice zone (MIZ) is the outer sea ice zone, its behavior is key to the understanding of the variability of sea ice extent associated with climate change. Especially for the melting processes in MIZ, where relatively small ice floes are dominant, floe size distribution (FSD) is an important parameter because smaller ice floes are subject to stronger lateral melting due to their larger cumulative perimeters. As the MIZ is characterized by vigorous interaction between sea ice and waves, breakup of sea ice due to flexural forcing and collisions is considered to play an essential role in the determination of FSD there. However, the available data have been very limited so far. Analysis of the observations of ice floes with a heli-borne video camera, focusing on the floe size ranging from 2 m to 100 m, in the Sea of Okhotsk, the Weddell Sea and off East Antarctica, revealed that while FSD is basically scale-invariant, a regime shift occurs at a size of about a few tens of meters, irrespective of the study region. It was also shown 1) that the floe size at which regime shift occurs slightly increases from 20 to 40 m with ice thickness, consistent with the theory of the flexural failure of sea ice; and 2) that to explain the scale invariance in FSD for smaller floes, a fragility of sea ice which is relevant to the strength of sea ice relative to waves can be a useful physical parameter to be correlated with the fractal dimension. Thus these results confirm the importance of wave-ice interaction to the formation of FSD. Based on this, a possible mechanism of the melting process was hypothesized that in the melting season sea ice extent retreats keeping the FSD relative to the ice edge nearly constant. As a next step and to confirm and further investigate this result, we planned to conduct the concurrent measurements of FSD, wave activities, and ice thickness off East Antarctica during the Sea Ice Physics and Ecosystem Experiment 2 (SIPEX2) in September to

  9. Gene tree discordance of wild and cultivated Asian rice deciphered by genome-wide sequence comparison.

    PubMed

    Yang, Ching-chia; Sakai, Hiroaki; Numa, Hisataka; Itoh, Takeshi

    2011-05-15

    Although a large number of genes are expected to correctly solve a phylogenetic relationship, inconsistent gene tree topologies have been observed. This conflicting evidence in gene tree topologies, known as gene tree discordance, becomes increasingly important as advanced sequencing technologies produce an enormous amount of sequence information for phylogenomic studies among closely related species. Here, we aim to characterize the gene tree discordance of the Asian cultivated rice Oryza sativa and its progenitor, O. rufipogon, which will be an ideal case study of gene tree discordance. Using genome and cDNA sequences of O. sativa and O. rufipogon, we have conducted the first in-depth analyses of gene tree discordance in Asian rice. Our comparison of full-length cDNA sequences of O. rufipogon with the genome sequences of the japonica and indica cultivars of O. sativa revealed that 60% of the gene trees showed a topology consistent with the expected one, whereas the remaining genes supported significantly different topologies. Moreover, the proportions of the topologies deviated significantly from expectation, suggesting at least one hybridization event between the two subgroups of O. sativa, japonica and indica. In fact, a genome-wide alignment between japonica and indica indicated that significant portions of the indica genome are derived from japonica. In addition, literature concerning the pedigree of the indica cultivar strongly supported the hybridization hypothesis. Our molecular evolutionary analyses deciphered complicated evolutionary processes in closely related species. They also demonstrated the importance of gene tree discordance in the era of high-speed DNA sequencing.

  10. Perspectives on deciphering mechanisms underlying plant heat stress response and thermotolerance

    PubMed Central

    Bokszczanin, Kamila L.; Fragkostefanakis, Sotirios

    2013-01-01

    Global warming is a major threat for agriculture and food safety and in many cases the negative effects are already apparent. The current challenge of basic and applied plant science is to decipher the molecular mechanisms of heat stress response (HSR) and thermotolerance in detail and use this information to identify genotypes that will withstand unfavorable environmental conditions. Nowadays X-omics approaches complement the findings of previous targeted studies and highlight the complexity of HSR mechanisms giving information for so far unrecognized genes, proteins and metabolites as potential key players of thermotolerance. Even more, roles of epigenetic mechanisms and the involvement of small RNAs in thermotolerance are currently emerging and thus open new directions of yet unexplored areas of plant HSR. In parallel it is emerging that although the whole plant is vulnerable to heat, specific organs are particularly sensitive to elevated temperatures. This has redirected research from the vegetative to generative tissues. The sexual reproduction phase is considered as the most sensitive to heat and specifically pollen exhibits the highest sensitivity and frequently an elevation of the temperature just a few degrees above the optimum during pollen development can have detrimental effects for crop production. Compared to our knowledge on HSR of vegetative tissues, the information on pollen is still scarce. Nowadays, several techniques for high-throughput X-omics approaches provide major tools to explore the principles of pollen HSR and thermotolerance mechanisms in specific genotypes. The collection of such information will provide an excellent support for improvement of breeding programs to facilitate the development of tolerant cultivars. The review aims at describing the current knowledge of thermotolerance mechanisms and the technical advances which will foster new insights into this process. PMID:23986766

  11. Conquering the Mesoscale of Africa's Landscapes: deciphering the Genomic Record of Individuating Landforms with Geoecodynamics

    NASA Astrophysics Data System (ADS)

    Cotterill, Fenton P. D.

    2016-04-01

    In the framework of Earth System Science, landscapes are the templates structuring the biosphere: the membranes interfacing between exosphere and geosphere. The hosts of earth surface processes, in their dynamics and complexity, landscapes hold a pivotal position in the evolving earth system - not least in their archives of Earth history. Their landforms document impacts of formative events originating in extra-terrestrial, geological and climatic processes. Nevertheless, major challenges to reconstruct dynamics at this interface between geosphere and exosphere hamper research efforts. Events at the mesoscale over evolutionary timescales are an important reason for why the academic schools of mega- versus process geomorphology persist (see Summerfield MA 2005. Trans. Inst. Brit Geogr NS, 30, 402-415). Austere limits on what their respective methods can reveal in mesoscale phenomena face several problems (besides costs of sampling and analyses). One, surviving landforms often lack the requisite minerals (e.g. of volcanic events). Second, the spatial resolution of orthodox methods (e.g. thermochronology) cannot resolve mesoscale patterns. Third, the surface dating tools with superb spatial precision have finitee temporal limits (Luminescence-Dating and Cosmogenic Isotopes). Fourth, and by no means least, the cumulative impact of earth surface processes has overwritten and/or eroded physical evidence of earlier formative events. (This problem is exemplified in tropical landscapes where deep, pervasive bioturbation is the dominant earth surface process!) The cumulative outcome of these inherent turnovers of landscapes has shaped the inherent emptiness of the Rock Record, which sets absolute limits on its archives (Ager D 1993. The Nature of the Stratigraphical Record; Miall AD 2015. in: Strata and Time: Probing the Gaps in Our Understanding. Geological Society, London, Special Publications, 404, http://dx.doi.org/10.1144/SP404.4). These limitations on mesoscale

  12. Determining the locus of a processing zone in an in situ oil shale retort through a well in the formation adjacent the retort

    SciTech Connect

    Ridley, R.D.

    1982-08-17

    The locus of a processing zone advancing through a fragmented permeable mass of formation particles in an in situ oil shale retort in a subterranean formation containing oil shale is determined by monitoring in a well extending through unfragmented formation adjacent the retort, for condition in the retort affected by the advancement of such a processing zone through the retort. Monitoring can be effected by placing means for monitoring such a condition in such a well extending through unfragmented formation adjacent the retort.

  13. Martian subsurface properties and crater formation processes inferred from fresh impact crater geometries

    NASA Astrophysics Data System (ADS)

    Stewart, Sarah T.; Valiant, Gregory J.

    2006-10-01

    nonballistic emplacement processes and/or bulking. The observations require a modification of the scaling laws and are well fit using a scaling factor of ˜1.4 between the transient crater surface diameter to the final crater rim diameter and excavation flow originating from one projectile diameter depth with Z = 2.7. The refined excavation model provides the first observationally constrained set of initial parameters for study of the formation of fluidized ejecta blankets on Mars.

  14. VizieR Online Data Catalog: Deuteration in massive star formation process (Fontani+, 2015)

    NASA Astrophysics Data System (ADS)

    Fontani, F.; Busquet, G.; Palau, A.; Caselli, P. Sanchez-Monge A.; Tan, J. C.; Audard, M.

    2014-11-01

    An ever growing number of observational and theoretical evidence suggests that the deuterated fraction (column density ratio between a species containing D and its hydrogenated counterpart, Dfrac) is an evolutionary indicator both in the low- and the high-mass star formation process. However, the role of surface chemistry in these studies has not been quantified from an observational point of view. In order to compare how the deuterated fractions of species formed only in the gas and partially or uniquely on grain surfaces evolve with time, we observed rotational transitions of CH3OH, 13CH3OH, CH2DOH, CH3OD at 3 and 1.3mm, and of NH2D at 3mm with the IRAM-30m telescope, and the inversion transitions (1,1) and (2,2) of NH3 with the GBT, towards most of the cores already observed by Fontani et al. (2011A&A...529L...7F, 2014MNRAS.440..448F) in N2H+, N2D+, HNC, DNC. NH2D is detected in all but two cores, regardless of the evolutionary stage. Dfrac(NH3) is on average above 0.1, and does not change significantly from the earliest to the most evolved phases, although the highest average value is found in the protostellar phase (~0.3). Few lines of CH2DOH and CH3OD are clearly detected, and only towards protostellar cores or externally heated starless cores. This work clearly confirms an expected different evolutionary trend of the species formed exclusively in the gas (N2D+ and N2H+) and those formed partially (NH2D and NH3) or totally (CH2DOH and CH3OH) on grain mantles. The study also reinforces the idea that Dfrac(N2H+) is the best tracer of massive starless cores, while high values of Dfrac(CH3OH) seem rather good tracers of the early protostellar phases, at which the evaporation/sputtering of the grain mantles is most efficient. (6 data files).

  15. Formation of interstellar solid CO{_2} after energetic processing of icy grain mantles

    NASA Astrophysics Data System (ADS)

    Ioppolo, S.; Palumbo, M. E.; Baratta, G. A.; Mennella, V.

    2009-01-01

    Context: Space infrared observations with ISO-SWS and Spitzer telescopes have clearly shown that solid carbon dioxide (CO{2}) is ubiquitous and abundant along the line of sight to quiescent clouds and star forming regions. Due to the CO2 low gas-phase abundance, it is suggested that CO{2} is synthesized on grains after energetic processing of icy mantles and/or surface reactions. Aims: We study quantitatively the abundance of carbon dioxide synthesized from ice mixtures of astrophysical relevance induced by ion irradiation at low temperature. We compare the CO{2} stretching and bending-mode band profiles observed towards some young stellar objects (YSOs) for which infrared spectra exist. Methods: Using a high vacuum experimental setup, the effects induced by fast ions (30-200 keV) on several ice mixtures of astrophysical interest are investigated. Chemical and structural modifications of the ice samples that form new molecular species are analyzed using infrared spectroscopy. The formation cross section of solid CO{2} is estimated from the increase in column density as a function of the dose fitting of experimental data with an exponential curve. Results: Our laboratory experiments showed that carbon dioxide is formed after irradiation of ice mixtures containing C- and O-bearing molecules. Furthermore, when the same amount of energy is released into the icy sample, a larger amount of CO{2} is formed in H{2}O-rich mixtures in agreement with previous studies. We also found that the CO2 stretching and bending mode band profiles depend on the mixture and temperature of the ice sample. We found that the amount of carbon dioxide formed after ion irradiation can account for the observed carbon dioxide towards YSOs. Furthermore, we discovered that laboratory spectra are a good spectroscopic analogue of the interstellar features. Conclusions: Even if the comparison between laboratory and observed spectra presented here cannot be considered unique and complete, our results

  16. Gamma band synchronization and the formation of representations in visual word processing: evidence from repetition and homophone priming.

    PubMed

    Matsumoto, Atsushi; Iidaka, Tetsuya

    2008-11-01

    The formation of an object's cortical representation seems to rely on synchronized neuronal activity within the gamma band frequency range (gamma band activity [GBA]). In this study, we investigated whether electroencephalogram (EEG) GBA, and its phase synchronization between electrodes, is necessary for the formation of nonobject higher-order cognitive representations, using both repetition and homophone priming tasks. In a repetition priming task, the formation of orthographic, phonological, and semantic representations is promoted by a prime word, whereas in the homophone priming task, the formation of only phonological representations is promoted. In the present study, the lexical processing of a target word induced GBA. In the repetition priming task, induced GBA and phase synchronization were decreased by presentation of the prime word (i.e., a repetition suppression effect) within both 200-300 msec and 400-500 msec time windows. In the homophone priming task, the repetition suppression effect was observed only within the 400-500 msec time window. The fact that repetition suppression effects were found in both priming tasks indicates that GBA and phase synchronization are necessary for the formation of phonological and semantic representations of a word. These results also suggest that formation of orthographic and higher-order cognitive representations occurred over different time courses.

  17. Examination of the formation process of pre-solvated and solvated electron in n-alcohol using femtosecond pulse radiolysis

    NASA Astrophysics Data System (ADS)

    Toigawa, Tomohiro; Gohdo, Masao; Norizawa, Kimihiro; Kondoh, Takafumi; Kan, Koichi; Yang, Jinfeng; Yoshida, Yoichi

    2016-06-01

    The formation process of pre-solvated and solvated electron in methanol (MeOH), ethanol (EtOH), n-butanol (BuOH), and n-octanol (OcOH) were investigated using a fs-pulse radiolysis technique by observing the pre-solvated electron at 1400 nm. The formation time constants of the pre-solvated electrons were determined to be 1.2, 2.2, 3.1, and 6.3 ps for MeOH, EtOH, BuOH, and OcOH, respectively. The formation time constants of the solvated electrons were determined to be 6.7, 13.6, 22.2, and 32.9 ps for MeOH, EtOH, BuOH, and OcOH, respectively. The formation dynamics and structure of the pre-solvated and solvated electrons in n-alcohols were discussed based on relation between the obtained time constant and dielectric relaxation time constant from the view point of kinetics. The observed formation time constants of the solvated electrons seemed to be strongly correlated with the second component of the dielectric relaxation time constants, which are related to single molecule motion. On the other hand, the observed formation time constants of the pre-solvated electrons seemed to be strongly correlated with the third component of the dielectric relaxation time constants, which are related to dynamics of hydrogen bonds.

  18. Deciphering the Origin of Plume-Textured Geodes.

    ERIC Educational Resources Information Center

    Garlick, George Donald; Jones, Francis Tucker

    1990-01-01

    Presented is an interpretation of the inward and outward growth and formation of plume textured geodes available from southern Brazil. Field occurrence, morphology of vesicles, growth history, closure of the agate shell, microscopic features, coherent reflection of light from convoluted surfaces, and accessory minerals of the inner cavity are…

  19. Variations and factors that influence the formation of polychlorinated naphthalenes in cement kilns co-processing solid waste.

    PubMed

    Jin, Rong; Zhan, Jiayu; Liu, Guorui; Zhao, Yuyang; Zheng, Minghui

    2016-09-05

    Pilot studies of unintentionally produced pollutants should be performed before waste being co-processed in cement kilns. Polychlorinated naphthalene (PCN) formation and emission from cement kilns co-processing sorted municipal solid waste, sewage sludge, and waste acid, however, have not previously been studied. Here, PCNs were analyzed in stack gas samples and solid samples from different stages of three cement production runs. PCN destruction efficiencies were higher when waste was co-processed (93.1% and 88.7% in two tests) than when waste was not co-processed (39.1%), so co-processing waste would not increase PCN outputs. The PCN concentrations were higher in particle samples from the C1 preheater and stages at back end of kiln than in particle samples from other stages, suggesting that cyclone preheater and back end of kiln should be focused for controlling PCN emissions. Besides that, based on the variation of PCN concentrations and corresponding operating conditions in different stages, the temperature, feeding materials, and chlorine content were suggested as the main factors influencing PCN formation. The PCN homologue and congener profiles suggested chlorination and dechlorination were the main PCN formation and decomposition pathways, and congeners CN-23, CN-46, and CN-59 appear to be appropriate indicators of PCNs emitted from coal-burning sources.

  20. Micro/nanostructures formation by femtosecond laser surface processing on amorphous and polycrystalline Ni60Nb40

    NASA Astrophysics Data System (ADS)

    Peng, Edwin; Tsubaki, Alfred; Zuhlke, Craig A.; Wang, Meiyu; Bell, Ryan; Lucis, Michael J.; Anderson, Troy P.; Alexander, Dennis R.; Gogos, George; Shield, Jeffrey E.

    2017-02-01

    Femtosecond laser surface processing is a technology that can be used to functionalize many surfaces, imparting specialized properties such as increased broadband optical absorption or superhydrophilicity/superhydrophobicity. In this study, two unique classes of surface structures, below surface growth (BSG) and above surface growth (ASG) mounds, were formed by femtosecond laser surface processing on amorphous and polycrystalline Ni60Nb40 with two different grain sizes. Cross sectional imaging of these mounds revealed thermal evidence of the unique formation processes for each class of surface structure. BSG mounds formed on all three substrates using the same laser parameters had similar surface morphology. The microstructures in the mounds were unaltered compared with the substrate before laser processing, suggesting their formation was dominated by preferential valley ablation. ASG mounds had similar morphology when formed on the polycrystalline Ni60Nb40 substrates with 100 nm and 2 μm grain size. However, the ASG mounds had significantly wider diameter and higher peak-to-valley heights when the substrate was amorphous Ni60Nb40. Hydrodynamic melting was primarily responsible for ASG mound formation. On amorphous Ni60Nb40 substrates, the ASG mounds are most likely larger due to lower thermal diffusivity. There was clear difference in growth mechanism of femtosecond laser processed BSG and ASG mounds, and grain size does not appear to be a factor.

  1. A comparison of iodinated trihalomethane formation from chlorine, chlorine dioxide and potassium permanganate oxidation processes.

    PubMed

    Zhang, Tian-Yang; Xu, Bin; Hu, Chen-Yan; Lin, Yi-Li; Lin, Lin; Ye, Tao; Tian, Fu-Xiang

    2015-01-01

    This study compared the formation of iodinated trihalomethanes (I-THMs) from iodide-containing raw waters oxidized by chlorine, chlorine dioxide (ClO₂) and potassium permanganate (KMnO₄) at different oxidant concentrations, reaction times, pHs, initial iodide concentrations and bromide to iodide mass ratios. Among the six investigated I-THMs, iodoform was the major species formed during the oxidation using chlorine, ClO₂ and KMnO₄. When oxidant concentration increased from 0.1 to 3.0 mg/L, the formation of I-THMs increased and then decreased for chlorine and ClO₂, but kept increasing for KMnO₄. As the reaction time went by, I-THM concentration increased to a plateau within 10 h (ClO₂ within only 1 h, especially) for all the three oxidants. I-THM formation gradually increased from pH 3.0 to 9.0 and remained stable at pH values higher than 7.5 for chlorine; however, for ClO₂ and KMnO₄ the highest I-THM formation showed at pH 7.0 and 7.5, respectively. As initial iodide concentration increased from 20 to 800 μg/L, the total amount and species of I-THMs increased for the three oxidants. Iodide contributed to I-THM formation much more significantly than bromide.

  2. Oxidation process of adrenaline in freshly isolated rat cardiomyocytes: formation of adrenochrome, quinoproteins, and GSH adduct.

    PubMed

    Costa, Vera Marisa; Silva, Renata; Ferreira, Luísa Maria; Branco, Paula Sério; Carvalho, Félix; Bastos, Maria Lourdes; Carvalho, Rui Albuquerque; Carvalho, Márcia; Remião, Fernando

    2007-08-01

    High concentrations of circulating biogenic catecholamines often exist during the course of several cardiovascular disorders. Additionally, coronary dysfunctions are prominent and frequently related to the ischemic and reperfusion phenomenon (I/R) in the heart, which leads to the release of large amounts of catecholamines, namely adrenaline, and to a sustained generation of reactive oxygen species (ROS). Thus, this work aimed to study the toxicity of adrenaline either alone or in the presence of a system capable of generating ROS [xanthine with xanthine oxidase (X/XO)], in freshly isolated, calcium tolerant cardiomyocytes from adult rats. Studies were performed for 3 h, and cardiomyocyte viability, ATP level, lipid peroxidation, protein carbonylation content, and glutathione status were evaluated, in addition to the formation of adrenaline's oxidation products and quinoproteins. Intracellular GSH levels were time-dependently depleted with no GSSG formation when cardiomyocytes were exposed to adrenaline or to adrenaline with X/XO. Meanwhile, a time-dependent increase in the rate of formation of adrenochrome and quinoproteins was observed. Additionally, as a new outcome, 5-(glutathion- S-yl)adrenaline, an adrenaline adduct of glutathione, was identified and quantified. Noteworthy is the fact that the exposure to adrenaline alone promotes a higher rate of formation of quinoproteins and glutathione adduct, while adrenochrome formation is favored where ROS production is stimulated. This study shows that the redox status of the surrounding environment greatly influences adrenaline's oxidation pathway, which may trigger cellular changes responsible for cardiotoxicity.

  3. Terrain matching image pre-process and its format transform in autonomous underwater navigation

    NASA Astrophysics Data System (ADS)

    Cao, Xuejun; Zhang, Feizhou; Yang, Dongkai; Yang, Bogang

    2007-06-01

    matching precision directly influences the final precision of integrated navigation system. Image matching assistant navigation is spatially matching and aiming at two underwater scenery images coming from two different sensors matriculating of the same scenery in order to confirm the relative displacement of the two images. In this way, we can obtain the vehicle's location in fiducial image known geographical relation, and the precise location information given from image matching location is transmitted to INS to eliminate its location error and greatly enhance the navigation precision of vehicle. Digital image data analysis and processing of image matching in underwater passive navigation is important. In regard to underwater geographic data analysis, we focus on the acquirement, disposal, analysis, expression and measurement of database information. These analysis items structure one of the important contents of underwater terrain matching and are propitious to know the seabed terrain configuration of navigation areas so that the best advantageous seabed terrain district and dependable navigation algorithm can be selected. In this way, we can improve the precision and reliability of terrain assistant navigation system. The pre-process and format transformation of digital image during underwater image matching are expatiated in this paper. The information of the terrain status in navigation areas need further study to provide the reliable data terrain characteristic and underwater overcast for navigation. Through realizing the choice of sea route, danger district prediction and navigating algorithm analysis, TAN can obtain more high location precision and probability, hence provide technological support for image matching of underwater passive navigation.

  4. Formation of alkali-metal nanoparticles in alkali-silicate glasses under electron irradiation and thermal processing

    NASA Astrophysics Data System (ADS)

    Bochkareva, E. S.; Sidorov, A. I.; Ignat'ev, A. I.; Nikonorov, N. V.; Podsvirov, O. A.

    2017-02-01

    Experiments and numerical simulation show that the irradiation of alkali-containing glasses using electrons at an energy of 35 keV and the subsequent thermal processing at a temperature above the vitrification point lead to the formation of spherical metal (lithium, sodium, and potassium) nanoparticles with oxide sheaths that exhibit plasmon resonances in the visible spectral range. Glasses containing two alkali metals exhibit mutual effect of metals on the formation of nanoparticles with two compositions due to the difference of ion radii and mobilities of metal ions.

  5. Observations from practice: support group membership as a process of social capital formation among female survivors of domestic violence.

    PubMed

    Larance, Lisa Young; Porter, Maryann Lane

    2004-06-01

    This article explores the authors' practice observations of female domestic violence survivors' journey from first agency contact to active participation in a support group process. The authors have witnessed female victims of domestic violence challenging the social isolation imposed by their dominant partners as they search for meaning in their lives. As practitioners, they have observed women building trustful relationships and establishing supportive networks during the group process. In this article, the authors suggest that the support group process facilitates trust and network formation indicative of social capital.

  6. Comparison of Phases Formation Process in Initial and Mechanically Activated Ceramic Batches with Pyrochlore Formulations

    SciTech Connect

    Stefanovsky, S. V.; Chizhevskaya, S. V.; Yudintsev, S. V.

    2002-02-25

    Formation of two pyrochlore ceramics with formulations CaZr0.25U0.75Ti2O7 and CaUTi2O7 within the temperature range 1000-1500 C from batches prepared by grinding of oxide powders in a mortar and an activator with hydrostatic yokes AGO-2U as well as soaking of a Ca, Zr, and Ti oxide mixture with uranylnitrate solution was studied. The pyrochlore ceramics are produced through intermediate calcium uranate formation. Phase formation reactions in the batch pre-treated in the AGO-2U unit were completed within the temperature range 1000-1100 C that is lower than in the batches prepared by two other methods.

  7. Fractionation, characterization and C-, N-disinfection byproduct formation of soluble microbial products in MBR processes.

    PubMed

    Ma, Defang; Meng, Yingjie; Xia, Chufan; Gao, Baoyu; Wang, Yan

    2015-12-01

    Soluble microbial products are heterogeneous organic materials generated during microbial growth and decay, which are the major soluble organic matters in MBR effluents and are the primary precursors forming disinfection by-products (DBPs). In this study, biomass associated products (BAP) and utilization associated products (UAP) were separately produced to investigate their physical chemical characteristics and disinfection byproduct (DBP) formation during chlorination in the presence of ammonia. BAP had higher formation reactivity of halogenated carbonaceous and nitrogenous DBPs including trihalomethanes, haloketones, haloacetonitriles and trichloronitromethane due to their higher percentage of large molecular weight (MW) materials and humic substances compared with UAP. However, the nonhalogenated species N-nitrosodimethylamine (NDMA) yield of UAP was twice higher than that of BAP because UAP contained more nitrogenous organic matters with MW<500Da including aromatic polypeptide/amino acid-like materials and secondary amines, which have been proved to have high NDMA formation potential.

  8. Perfluorooctanoic Acid Degradation Using UV-Persulfate Process: Modeling of the Degradation and Chlorate Formation.

    PubMed

    Qian, Yajie; Guo, Xin; Zhang, Yalei; Peng, Yue; Sun, Peizhe; Huang, Ching-Hua; Niu, Junfeng; Zhou, Xuefei; Crittenden, John C

    2016-01-19

    In this study, we investigated the destruction and by-product formation of perfluorooctanoic acid (PFOA) using ultraviolet light and persulfate (UV-PS). Additionally, we developed a first-principles kinetic model to simulate both PFOA destruction and by-product and chlorate (ClO3(-)) formation in ultrapure water (UW), surface water (SW), and wastewater (WW). PFOA degradation was significantly suppressed in the presence of chloride and carbonate species and did not occur until all the chloride was converted to ClO3(-) in UW and for low DOC concentrations in SW. The model was able to simulate the PS decay, pH changes, radical concentrations, and ClO3(-) formation for UW and SW. However, our model was unable to simulate PFOA degradation well in WW, possibly from PS activation by NOM, which in turn produced sulfate radicals.

  9. Contemporary Role of the Decipher® Test in Prostate Cancer Management: Current Practice and Future Perspectives

    PubMed Central

    Dalela, Deepansh; Löppenberg, Björn; Sood, Akshay; Sammon, Jesse; Abdollah, Firas

    2016-01-01

    We performed a systematic literature search to identify original articles and editorials about the Decipher® Prostate Cancer Test (GenomeDx Biosciences, San Diego, CA) to provide an overview of the current literature and its present role in urologic clinical practice. The Decipher test, which uses the expression of 22 selected RNA markers (from a total of over 1.4 million), showed a very high discrimination in predicting clinical metastasis (0.75–0.83) and cancer-specific mortality (0.78) in external validation studies, outperforming all routinely available clinicopathologic characteristics. Further, the timing of postoperative radiotherapy (adjuvant vs salvage) may be guided based on Decipher scores. The Decipher test was also the only independent predictor of clinical metastasis in patients with biochemical recurrence after surgery. The Decipher Genomic Resource Information Database (GRID) is a novel research tool that captures 1.4 million marker expressions per patient and may facilitate precision-guided, individualized care to patients with prostate cancer. In this era of precision medicine, Decipher, along with the Decipher GRID platform, is a promising genomic tool that may aid in managing prostate cancer patients throughout the continuum of care and delivering appropriate treatment at an individualized level. PMID:27162506

  10. [A mathematical model of hemodynamic processes for distal pulse wave formation].

    PubMed

    Fedotov, A A

    2015-01-01

    A mathematical model of the formation of distal arterial pulse wave signal in the blood vessels of the upper limbs was considered. The formation of distal arterial pulse wave is represented as a composition of forward and reverse pulse waves propagating along the human arterial system. The system of formal analogy between pulse waves propagation along the human arterial system and the propagation of electrical oscillations in electrical transmission lines with distributed parameters was proposed. Dependencies of pulse wave propagation along the human arterial system were obtained by solving the one-dimensional Navier-Stokes equations for a few special cases.

  11. THE r-PROCESS IN METAL-POOR STARS AND BLACK HOLE FORMATION

    SciTech Connect

    Boyd, R. N.; Famiano, M. A.; Meyer, B. S.; Motizuki, Y.; Kajino, T.; Roederer, I. U.

    2012-01-15

    Nucleosynthesis of heavy nuclei in metal-poor stars is generally thought to occur via the r-process because the r-process is a primary process that would have operated early in the Galaxy's history. This idea is strongly supported by the fact that the abundance pattern in many metal-poor stars matches well the inferred solar r-process abundance pattern in the mass range between the second and third r-process abundance peaks. Nevertheless, a significant number of metal-poor stars do not share this standard r-process template. In this Letter, we suggest that the nuclides observed in many of these stars are produced by the r-process, but that it is prevented from running to completion in more massive stars by collapse to black holes before the r-process is completed, creating a 'truncated r-process', or 'tr-process'. We find that the observed fraction of tr-process stars is qualitatively what one would expect from the initial mass function and that an apparent sharp truncation observed at around mass 160 could result from a combination of collapses to black holes and the difficulty of observing the higher mass rare-earth elements. We test the tr-process hypothesis with r-process calculations that are terminated before all r-process trajectories have been ejected. We find qualitative agreement between observation and theory when black hole collapse and observational realities are taken into account.

  12. Degradation of carbamazepine by UV/chlorine advanced oxidation process and formation of disinfection by-products.

    PubMed

    Zhou, Shiqing; Xia, Ying; Li, Ting; Yao, Tian; Shi, Zhou; Zhu, Shumin; Gao, Naiyun

    2016-08-01

    Pharmaceuticals in water are commonly found and are not efficiently removed by current treatment processes. Degradation of antiepileptic drug carbamazepine (CBZ) by UV/chlorine advanced oxidation process was systematically investigated in this study. The results showed that the UV/chlorine process was more effective at degrading CBZ than either UV or chlorination alone. The CBZ degradation followed pseudo-first order reaction kinetics, and the degradation rate constants (kobs) were affected by the chlorine dose, solution pH, and natural organic matter concentration to different degrees. Degradation of CBZ greatly increased with increasing chlorine dose and decreasing solution pH during the UV/chlorine process. Additionally, the presence of natural organic matter in the solution inhibited the degradation of CBZ. UV photolysis, chlorination, and reactive species (hydroxyl radical •OH and chlorine atoms •Cl) were identified as responsible for CBZ degradation in the UV/chlorine process. Finally, a degradation pathway for CBZ in the UV/chlorine process was proposed and the formation potentials of carbonaceous and nitrogenous disinfection by-products were evaluated. Enhanced formation of trichloroacetic acid, dichloroacetonitrile, and trichloronitromethane precursors should be considered when applying UV/chlorine advanced oxidation process to drinking water.

  13. Multi-format all-optical processing based on a large-scale, hybridly integrated photonic circuit.

    PubMed

    Bougioukos, M; Kouloumentas, Ch; Spyropoulou, M; Giannoulis, G; Kalavrouziotis, D; Maziotis, A; Bakopoulos, P; Harmon, R; Rogers, D; Harrison, J; Poustie, A; Maxwell, G; Avramopoulos, H

    2011-06-06

    We investigate through numerical studies and experiments the performance of a large scale, silica-on-silicon photonic integrated circuit for multi-format regeneration and wavelength-conversion. The circuit encompasses a monolithically integrated array of four SOAs inside two parallel Mach-Zehnder structures, four delay interferometers and a large number of silica waveguides and couplers. Exploiting phase-incoherent techniques, the circuit is capable of processing OOK signals at variable bit rates, DPSK signals at 22 or 44 Gb/s and DQPSK signals at 44 Gbaud. Simulation studies reveal the wavelength-conversion potential of the circuit with enhanced regenerative capabilities for OOK and DPSK modulation formats and acceptable quality degradation for DQPSK format. Regeneration of 22 Gb/s OOK signals with amplified spontaneous emission (ASE) noise and DPSK data signals degraded with amplitude, phase and ASE noise is experimentally validated demonstrating a power penalty improvement up to 1.5 dB.

  14. Spontaneous formation of 10-μm-scale periodic patterns in transverse-scanning femtosecond laser processing.

    PubMed

    Matsuo, Shigeki; Hashimoto, Shuichi

    2015-01-12

    We report spontaneous formation of 10-μm-scale periodic patterns in transverse-scanning femtosecond (fs) laser processing inside a glass substrate. The formation of the periodic patterns was critically dependent on the distance of the focus from the back surface; they formed only when fs pulses were focused slightly inside (∼ a few micrometers) from the back surface. The periods ranged from 7 to 16 μm, which is much longer than the distance between neighboring irradiation spots (0.1-1 μm in the present experiments), the diameter of the individual modified spots (about 2 μm), and the wavelength (0.8 μm). The patterns formed without any intentional modulation; just by scanning the sample at a constant speed during irradiation of fs laser pulses. The dependence on scanning speed and repetition rate of the laser were also investigated, and a possible formation scenario for this "long" periodic pattern was described.

  15. Modulation of Task Demands Suggests That Semantic Processing Interferes with the Formation of Episodic Associations

    ERIC Educational Resources Information Center

    Long, Nicole M.; Kahana, Michael J.

    2017-01-01

    Although episodic and semantic memory share overlapping neural mechanisms, it remains unclear how our pre-existing semantic associations modulate the formation of new, episodic associations. When freely recalling recently studied words, people rely on both episodic and semantic associations, shown through temporal and semantic clustering of…

  16. Experimental studies of nucleation and growth processes related to the formation of presolar grains

    NASA Technical Reports Server (NTRS)

    Berg, Otto E.

    1992-01-01

    An understanding was sought for the mechanisms of nucleation of refractory materials, and the relative importance of factors controlling the rate of cluster formation and growth for astrophysically important species. The structure and composition of the condensates is being studied, with the goal of characterizing the grains present in the primitive solar nebula.

  17. The Formation and Development of Cognitive Activity of Students in the Learning Process

    ERIC Educational Resources Information Center

    Saparkyzy, Zhannat; Isatayeva, Gulzhan; Kozhabekova, Zahida; Zhakesheva, Aimzhan; Koptayeva, Gulzhamal; Agabekova, Gulzhan; Agabekova, Sholpan

    2016-01-01

    In this article we will discuss how the holding of a special and dedicated work helped to change the levels of formation of the major components of cognitive activity. Cognitive activity with the content aspect is a system of perceptual, mnemonic and intellectual activity and from the form--as an individual, joint, or pseudo-individual pseudo…

  18. Interpreting the developmental dance of the megakaryocyte: a review of the cellular and molecular processes mediating platelet formation.

    PubMed

    Machlus, Kellie R; Thon, Jonathan N; Italiano, Joseph E

    2014-04-01

    Platelets are essential for haemostasis, and thrombocytopenia (platelet counts <150 × 10(9) /l) is a major clinical problem encountered across a number of conditions, including immune thrombocytopenic purpura, myelodysplastic syndromes, chemotherapy, aplastic anaemia, human immunodeficiency virus infection, complications during pregnancy and delivery, and surgery. Circulating blood platelets are specialized cells that function to prevent bleeding and minimize blood vessel injury. Platelets circulate in their quiescent form, and upon stimulation, activate to release their granule contents and spread on the affected tissue to create a physical barrier that prevents blood loss. The current model of platelet formation states that large progenitor cells in the bone marrow, called megakaryocytes, release platelets by extending long, branching processes, designated proplatelets, into sinusoidal blood vessels. This review will focus on different factors that impact megakaryocyte development, proplatelet formation and platelet release. It will highlight recent studies on thrombopoeitin-dependent megakaryocyte maturation, endomitosis and granule formation, cytoskeletal contributions to proplatelet formation, the role of apoptosis, and terminal platelet formation and release.

  19. Contribution of Neutron Star Mergers to the r-Process Chemical Evolution in the Hierarchical Galaxy Formation

    NASA Astrophysics Data System (ADS)

    Komiya, Yutaka; Shigeyama, Toshikazu

    2016-10-01

    The main astronomical source of r-process elements has not yet been identified. One plausible site is neutron star mergers (NSMs), but from the perspective of the Galactic chemical evolution, it has been pointed out that NSMs cannot reproduce the observed r-process abundance distribution of metal-poor stars at [{Fe}/{{H}}]\\lt -3. Recently, Tsujimoto & Shigeyama pointed out that NSM ejecta can spread into a much larger volume than ejecta from a supernova. We re-examine the enrichment of r-process elements by NSMs considering this difference in propagation using the chemical evolution model under the hierarchical galaxy formation. The observed r-process enhanced stars around [{Fe}/{{H}}]∼ -3 are reproduced if the star formation efficiency is lower for low-mass galaxies under a realistic delay-time distribution for NSMs. We show that a significant fraction of NSM ejecta escape from its host proto-galaxy to pollute intergalactic matter and other proto-galaxies. The propagation of r-process elements over proto-galaxies changes the abundance distribution at [{Fe}/{{H}}]\\lt -3 and obtains distribution compatible with observations of the Milky Way halo stars. In particular, the pre-enrichment of intergalactic medium explains the observed scarcity of extremely metal-poor stars without Ba and abundance distribution of r-process elements at [{Fe}/{{H}}]≲ -3.5.

  20. Deciphering the glycosaminoglycan code with the help of microarrays.

    PubMed

    de Paz, Jose L; Seeberger, Peter H

    2008-07-01

    Carbohydrate microarrays have become a powerful tool to elucidate the biological role of complex sugars. Microarrays are particularly useful for the study of glycosaminoglycans (GAGs), a key class of carbohydrates. The high-throughput chip format enables rapid screening of large numbers of potential GAG sequences produced via a complex biosynthesis while consuming very little sample. Here, we briefly highlight the most recent advances involving GAG microarrays built with synthetic or naturally derived oligosaccharides. These chips are powerful tools for characterizing GAG-protein interactions and determining structure-activity relationships for specific sequences. Thereby, they contribute to decoding the information contained in specific GAG sequences.

  1. Statistical synthesis of radiometric imaging formation in scanning radiometers with signal weight processing by Kravchenko windows

    NASA Astrophysics Data System (ADS)

    Volosyuk, V. K.; Kravchenko, V. F.; Pavlikov, V. V.; Pustovoit, V. I.

    2014-05-01

    Statistical optimization of the radiometric images (RMIs) algorithms formation in scanning radiometers with weight correction of the antenna amplitude-phase distribution and synchronous sliding strobing of the received noise-like signal by a function describing the antenna pattern corrected by temporal Kravchenko windows is performed for the first time. The ambiguity function (AF) of the scanning radiometer, which determines the RMI quality, is found. It is established that the AF shape substantially depends on the amplitude field distribution (AFD) in the antenna. It is shown that the use of the AFD in the antenna in the form of weight functions (classic and Kravchenko) makes it possible to correct the AF shape and to increase the RMI quality. A simulation of the RMI formation algorithm is performed. It follows from the analysis of simulation data that the use of the weight Kravchenko functions provides higher accuracy of the RMI restoration compared with classic weight functions.

  2. Subnanosecond processes in the stage of breakdown formation in gas at a high pressure

    NASA Astrophysics Data System (ADS)

    Korolev, Yu. D.; Bykov, N. M.; Ivanov, S. N.

    2008-12-01

    Results are presented from experimental studies of the prebreakdown stage of a discharge in nitrogen at pressures of a few tens of atmospheres, gap voltages higher than 140 kV, and a voltage rise time of about 1 ns. Breakdown occurs at the front of the voltage pulse; i.e., the time of breakdown formation is shorter than the front duration. It is shown that, in gaps with a nonuniform electric field, the breakdown formation time is mainly determined by the time of avalanche development to the critical number of charge carriers. The subsequent stages of breakdown (the development of the ionization wave and the buildup of the conductivity in the weakly conducting channel bridging the gap) turn out to be shorter than this time or comparable to it.

  3. Investigation of HNCO isomer formation in ice mantles by UV and thermal processing: An experimental approach

    SciTech Connect

    Jiménez-Escobar, A.; Giuliano, B. M.; Caro, G. M. Muñoz; Cernicharo, J.; Marcelino, N.

    2014-06-10

    Current gas-phase models do not account for the abundances of HNCO isomers detected in various environments, suggesting their formation in icy grain mantles. We attempted to study a formation channel of HNCO and its possible isomers by vacuum-UV photoprocessing of interstellar ice analogs containing H{sub 2}O, NH{sub 3}, CO, HCN, CH{sub 3}OH, CH{sub 4}, and N{sub 2} followed by warm-up under astrophysically relevant conditions. Only the H{sub 2}O:NH{sub 3}:CO and H{sub 2}O:HCN ice mixtures led to the production of HNCO species. The possible isomerization of HNCO to its higher energy tautomers following irradiation or due to ice warm-up has been scrutinized. The photochemistry and thermal chemistry of H{sub 2}O:NH{sub 3}:CO and H{sub 2}O:HCN ices were simulated using the Interstellar Astrochemistry Chamber, a state-of-the-art ultra-high-vacuum setup. The ice was monitored in situ by Fourier transform mid-infrared spectroscopy in transmittance. A quadrupole mass spectrometer detected the desorption of the molecules in the gas phase. UV photoprocessing of H{sub 2}O:NH{sub 3}:CO and H{sub 2}O:HCN ices lead to the formation of OCN{sup –} as a main product in the solid state and a minor amount of HNCO. The second isomer HOCN has been tentatively identified. Despite its low efficiency, the formation of HNCO and the HOCN isomers by UV photoprocessing of realistic simulated ice mantles might explain the observed abundances of these species in photodissociation regions, hot cores, and dark clouds.

  4. Narrow-band radiation wavelength measurement by processing digital photographs in RAW format

    SciTech Connect

    Kraiskii, A V; Mironova, T V; Sultanov, T T

    2012-12-31

    The technique of measuring the mean wavelength of narrow-band radiation in the 455 - 625-nm range using the image of the emitting surface is presented. The data from the camera array unprocessed by the built-in processor (RAW format) are used. The method is applied for determining the parameters of response of holographic sensors. Depending on the wavelength and brightness of the image fragment, the mean square deviation of the wavelength amounts to 0.3 - 3 nm. (experimental techniques)

  5. Numerical modelling of the formation process of planets from protoplanetary cloud

    NASA Technical Reports Server (NTRS)

    Kozlov, N. N.; Eneyev, T. M.

    1979-01-01

    Evolution of the plane protoplanetary cloud, consisting of a great number of gravitationally interacting and uniting under collision bodies (protoplanets) moving in the central field of a large mass (the Sun or a planet), is considered. It is shown that in the course of protoplanetary cloud evolution the ring zones of matter expansion and compression occur with the subsequent development leading to formation of planets, rotating about their axes mainly directly. The principal numerical results were obtained through digital simulation of planetary accumulation.

  6. An investigation of voids formation mechanisms and their effects on freeze and thaw processes of lithium and lithium fluoride

    NASA Technical Reports Server (NTRS)

    El-Genk, Mohamed S.; Yang, Jae-Young

    1991-01-01

    The mechanisms of void formation during the cooldown and freezing of lithium coolant within the primary loop of SP-100 type systems are investigated. These mechanisms are: (1) homogeneous nucleation; (2) heterogeneous nucleation; (3) normal segregation of helium gas dissolved in liquid lithium; and (4) shrinkage of lithium during freezing. To evaluate the void formation potential due to segregation, a numerical scheme that couples the freezing and mass diffusion processes in both the solid and liquid regions is developed. The results indicated that the formation of He bubbles is unlikely by either homogeneous or heterogeneous nucleation during the cooldown process. However, homogeneous nucleation of He bubbles following the segregation of dissolved He in liquid lithium ahead of the solid-liquid interface is likely to occur. Results also show that total volume of He void is insignificant when compared to that of shrinkage voids. In viewing this, the subsequent research focuses on the effects of shrinkage void forming during freezing of lithium on subsequent thaw processes are investigated using a numerical scheme that is based on a single (solid/liquid) cell approach. The cases of lithium-fluoride are also investigated to show the effect of larger volume shrinkage upon freezing on the freeze and thaw processes. Results show that a void forming at the wall appreciably reduces the solid-liquid interface velocity, during both freeze and thaw, and causes a substantial rise in the wall temperature during thaw. However, in the case of Li, the maximum wall temperature was much lower than the melting temperature of PWC-11, which is used as the structure material in the SP-100 system. Hence, it is included that a formation of hot spots is unlikely during the startup or restart of the SP-100 system.

  7. Antioxidant Compounds in Traditional Indian Pickles May Prevent the Process-Induced Formation of Benzene.

    PubMed

    Kharat, Mahesh M; Adiani, Vanshika; Variyar, Prasad; Sharma, Arun; Singhal, Rekha S

    2016-01-01

    Pickles in the Indian market contain ascorbic acid from the raw material used and benzoate as an added preservative that are involved in the formation of benzene in soft drinks. In this work, 24 market pickle samples were surveyed for benzene content, as well as its precursors and other constituents that influence its formation. The analysis showed that pickle samples were high in acid content (low pH) and showed significant amount of ascorbic acid, minerals (Cu and Fe), and benzoic acid present in them. Also, most samples exhibited high antioxidant activity that might be attributed to the ingredients used, such as fruits and spices. The solid-phase microextraction headspace gas chromatography-mass spectrometry method was developed in-house for benzene analysis. Eleven of 24 samples had benzene, with the highest concentration of 4.36 ± 0.82 μg of benzene per kg of pickle for a lime pickle that was also reported to have highest benzoic acid and considerably less hydroxyl radical ((•)OH) scavenging activity. However, benzene levels for all 11 samples were considerably below the World Health Organization regulatory limit of 10 μg/kg for benzene in mineral water. Studies on model systems revealed that the high antioxidant activity of Indian pickles may have had a strong inhibitory effect on benzene formation.

  8. Fundamental processes of protein folding: measuring the energetic balance between helix formation and hydrophobic interactions.

    PubMed

    Xian, Wujing; Connolly, Peter J; Oslin, Marcela; Hausrath, Andrew C; Osterhout, John J

    2006-09-01

    Theories of protein folding often consider contributions from three fundamental elements: loops, hydrophobic interactions, and secondary structures. The pathway of protein folding, the rate of folding, and the final folded structure should be predictable if the energetic contributions to folding of these fundamental factors were properly understood. alphatalpha is a helix-turn-helix peptide that was developed by de novo design to provide a model system for the study of these important elements of protein folding. Hydrogen exchange experiments were performed on selectively 15N-labeled alphatalpha and used to calculate the stability of hydrogen bonds within the peptide. The resulting pattern of hydrogen bond stability was analyzed using a version of Lifson-Roig model that was extended to include a statistical parameter for tertiary interactions. This parameter, x, represents the additional statistical weight conferred upon a helical state by a tertiary contact. The hydrogen exchange data is most closely fit by the XHC model with an x parameter of 9.25. Thus the statistical weight of a hydrophobic tertiary contact is approximately 5.8x the statistical weight for helix formation by alanine. The value for the x parameter derived from this study should provide a basis for the understanding of the relationship between hydrophobic cluster formation and secondary structure formation during the early stages of protein folding.

  9. Genes involved in Listeria monocytogenes biofilm formation at a simulated food processing plant temperature of 15 °C.

    PubMed

    Piercey, Marta J; Hingston, Patricia A; Truelstrup Hansen, Lisbeth

    2016-04-16

    Listeria monocytogenes is a pathogenic foodborne bacterium whose persistence in food processing environments is in part attributed to its biofilm formation. Most biofilm studies have been carried out at 30-37 °C rather than at temperatures found in the food processing plants (i.e., 10-20 °C). The objective of the present study was to mine for novel genes that contribute to L. monocytogenes biofilm formation at 15 °C using the random insertional mutagenesis approach. A library of 11,024 L. monocytogenes 568 (serotype 1/2a) Himar1 insertional mutants was created. Mutants with reduced or enhanced biofilm formation at 15 °C were detected in microtiter plate assays with crystal violet and safranin staining. Fourteen mutants expressed enhanced biofilm phenotypes, and harbored transposon insertions in genes encoding cell wall biosynthesis, motility, metabolism, stress response, and cell surface associated proteins. Deficient mutants (n=5) contained interruptions in genes related to peptidoglycan, teichoic acid, or lipoproteins. Enhanced mutants produced significantly (p<0.05) higher cell densities in biofilm formed on stainless steel (SS) coupons at 15 °C (48 h) than deficient mutants, which were also more sensitive to benzalkonium chloride. All biofilm deficient mutants and four enhanced mutants in the microtiter plate assay (flaA, cheR, lmo2563 and lmo2488) formed no biofilm in a peg lid assay (Calgary biofilm device) while insertions in lmo1224 and lmo0543 led to excess biofilm in all assays. Two enhanced biofilm formers were more resistant to enzymatic removal with DNase, proteinase K or pectinase than the parent strain. Scanning electron microscopy of individual biofilms made by five mutants and the parent on SS surfaces showed formation of heterogeneous biofilm with dense zones by immotile mutants, while deficient mutants exhibited sparse growth. In conclusion, interruptions of 9 genes not previously linked to biofilm formation in L. monocytogenes (lmo2572, lmo

  10. MAGNETOHYDRODYNAMIC MODELING FOR A FORMATION PROCESS OF CORONAL MASS EJECTIONS: INTERACTION BETWEEN AN EJECTING FLUX ROPE AND AN AMBIENT FIELD

    SciTech Connect

    Shiota, Daikou; Kusano, Kanya; Miyoshi, Takahiro; Shibata, Kazunari

    2010-08-01

    We performed a magnetohydrodynamic simulation of a formation process of coronal mass ejections (CMEs), focusing on the interaction (reconnection) between an ejecting flux rope and its ambient field. We examined three cases with different ambient fields: one had no ambient field, while the other two had dipole fields with opposite directions, parallel and anti-parallel to that of the flux rope surface. We found that while the flux rope disappears in the anti-parallel case, in the other cases the flux ropes can evolve to CMEs and show different amounts of flux rope rotation. The results imply that the interaction between an ejecting flux rope and its ambient field is an important process for determining CME formation and CME orientation, and also show that the amount and direction of the magnetic flux within the flux rope and the ambient field are key parameters for CME formation. The interaction (reconnection) plays a significant role in the rotation of the flux rope especially with a process similar to 'tilting instability' in a spheromak-type experiment of laboratory plasma.

  11. UV-based advanced oxidation processes for the treatment of odour compounds: efficiency and by-product formation.

    PubMed

    Zoschke, Kristin; Dietrich, Norman; Börnick, Hilmar; Worch, Eckhard

    2012-10-15

    The occurrence of the taste and odour compounds geosmin and 2-methyl isoborneol (2-MIB) affects the organoleptic quality of raw waters from drinking water reservoirs worldwide. UV-based oxidation processes for the removal of these substances are an alternative to adsorption and biological processes, since they additionally provide disinfection of the raw water. We could show that the concentration of geosmin and 2-MIB could be reduced by VUV irradiation and the combination of UV irradiation with ozone and hydrogen peroxide in pure water and water from a drinking water reservoir. The figure of merit EE/O is an appropriate tool to compare the AOPs and showed that VUV and UV/O(3) yielded the lowest treatment costs for the odour compounds in pure and raw water, respectively. Additionally, VUV irradiation with addition of ozone, generated by the VUV lamp, was evaluated. The generation of ozone and the irradiation were performed in a single reactor system using the same low-pressure mercury lamp, thereby reducing the energy consumption of the treatment process. The formation of the undesired by-products nitrite and bromate was investigated. The combination of VUV irradiation with ozone produced by a VUV lamp avoided the formation of relevant concentrations of the by-products. The internal generation of ozone is capable to produce ozone concentrations sufficient to reduce EE/O below 1 kWh m(-3) and without the risk of the formation of nitrite or bromate above the maximum contaminant level.

  12. The r-Process in Metal Poor Stars and Black Hole Formation

    SciTech Connect

    Boyd, R N; Famiano, M A; Meyer, B S; Motizuki, Y; Kajino, T; Roederer, I U

    2011-11-30

    Nucleosynthesis of heavy nuclei in metal-poor stars is generally ascribed to the r-process, as the abundance pattern in many such stars agrees with the inferred Solar r-process abundances. Nonetheless, a significant number of these stars do not share this r-process template. they suggest that many such stars have begun an r-process, but it was prevented from running to completion in more massive stars by collapse to black holes, creating a 'truncated r-process,' or 'tr-process'. The observed fraction of tr-process stars is found to be consistent with expectations from the initial mass function (IMF), and they suggest that an apparent sharp truncation observed at around mass 160 could result from a combination of collapses to black holes and the difficulty of observing the higher mass rare earths. They test the tr-process hypothesis with calculations that are terminated before all r-process trajectories have been ejected. These produce qualitative agreement with observation when both black hole collapse and observational realities are taken into account.

  13. Influence of the turbulence on the processes formation and relaxation of periodical artificial irregularities in the lower ionosphere

    NASA Astrophysics Data System (ADS)

    Terina, Galina

    2016-07-01

    The periodic artificial irregularities (PAI) are formed in the standing wave field of powerful radio emission. The study the scattering of probing radio pulses on PAI allowed to create a method diagnostics of the ionospheric plasma parameters - the resonance scattering method (RSM) of radio waves on the periodic artificial irregularities. The different mechanisms of PAI formation in D and E ranges of the lower ionosphere were investigated (G.I. Terina, J.Atm.Terr.Phys., 1996, 58, 645). However the height range 75-90 km where there is turbulent diffusion, remained unstudied. In present paper the study results the processes formation and relaxation of periodic artificial irregularities in this height range are considered. For the analysis the processes of the formation and the relaxation of PAI one can use quasi-hydrodynamic equation for the homogeneous isotropic ionospheric plasma. Under the small disturbances, quasi-neutral plasma and some assumptions can to obtain the differential equations for regular and fluctuation PAI parts, which take account: the ambipolar diffusion, the temperature dependence of the coefficient of electrons recombination, the temperature dependence of the coefficient of the electrons attachment to the neutral molecules and also the turbulent diffusion and caused by it small-scale irregularities of the electron density. The solutions of the inhomogeneous and homogeneous equations present the processes of the formation and relaxation of PAI accordingly. The numerical estimations of obtained solutions showed that the main reasons of PAI formation in considered range of heights are the small-scale irregularities of the electron concentration and the turbulence diffusion. The obtained results qualitatively agree with results of experimental investigations. The experiments were carried out at the heating facilities "Zimenki" and "Sura". The heater transmitter periodically was switched on for several seconds and off for the same duration. The

  14. Optimization of palm oil physical refining process for reduction of 3-monochloropropane-1,2-diol (3-MCPD) ester formation.

    PubMed

    Zulkurnain, Musfirah; Lai, Oi Ming; Tan, Soo Choon; Abdul Latip, Razam; Tan, Chin Ping

    2013-04-03

    The reduction of 3-monochloropropane-1,2-diol (3-MCPD) ester formation in refined palm oil was achieved by incorporation of additional processing steps in the physical refining process to remove chloroester precursors prior to the deodorization step. The modified refining process was optimized for the least 3-MCPD ester formation and acceptable refined palm oil quality using response surface methodology (RSM) with five processing parameters: water dosage, phosphoric acid dosage, degumming temperature, activated clay dosage, and deodorization temperature. The removal of chloroester precursors was largely accomplished by increasing the water dosage, while the reduction of 3-MCPD esters was a compromise in oxidative stability and color of the refined palm oil because some factors such as acid dosage, degumming temperature, and deodorization temperature showed contradictory effects. The optimization resulted in 87.2% reduction of 3-MCPD esters from 2.9 mg/kg in the conventional refining process to 0.4 mg/kg, with color and oil stability index values of 2.4 R and 14.3 h, respectively.

  15. Simulation of the Electric Signal During the Formation and Departure of Droplets in the Electroslag Remelting Process

    NASA Astrophysics Data System (ADS)

    Kharicha, A.; Wu, M.; Ludwig, A.; Karimi-Sibaki, E.

    2016-04-01

    In the ESR process, it is very difficult to make experimental observations of the phenomena occurring within the molten slag. At present, the state of the process is solely evaluated from the variation of the measured electric variables. The present paper proposes the use of 3D numerical model to explore the complex coupling existing between the electrodynamics and the phase distribution during the process. The droplet formation during melting of an electrode under the action of a strong DC current is simulated with a multiphase-magnetohydrodynamic approach. A volume-of-fluid approach is used for the interface tracking, and the potential formulation is used to determine the electric and magnetic fields. The Lorentz force and the Joule heating are recalculated at each time step as a function of the phase distribution. The evolution of the electric resistance of the system during the droplet formation and departure is reported. The results are compared with the measurements made in experimental and industrial-scale ESR processes. Two values of metal/slag interfacial tension of 1 and 0.1 N m-1 are explored. The effects of the control system as well as the presence of a horizontal magnetic field are also investigated. These results open the possibility to link online the voltage signal variation with real physical phenomena happening during the process.

  16. Semantic processes leading to true and false memory formation in schizophrenia.

    PubMed

    Paz-Alonso, Pedro M; Ghetti, Simona; Ramsay, Ian; Solomon, Marjorie; Yoon, Jong; Carter, Cameron S; Ragland, J Daniel

    2013-07-01

    Encoding semantic relationships between items on word lists (semantic processing) enhances true memories, but also increases memory distortions. Episodic memory impairments in schizophrenia (SZ) are strongly driven by failures to process semantic relations, but the exact nature of these relational semantic processing deficits is not well understood. Here, we used a false memory paradigm to investigate the impact of implicit and explicit semantic processing manipulations on episodic memory in SZ. Thirty SZ and 30 demographically matched healthy controls (HC) studied Deese/Roediger-McDermott (DRM) lists of semantically associated words. Half of the lists had strong implicit semantic associations and the remainder had low strength associations. Similarly, half of the lists were presented under "standard" instructions and the other half under explicit "relational processing" instructions. After study, participants performed recall and old/new recognition tests composed of targets, critical lures, and unrelated lures. HC exhibited higher true memories and better discriminability between true and false memory compared to SZ. High, versus low, associative strength increased false memory rates in both groups. However, explicit "relational processing" instructions positively improved true memory rates only in HC. Finally, true and false memory rates were associated with severity of disorganized and negative symptoms in SZ. These results suggest that reduced processing of semantic relationships during encoding in SZ may stem from an inability to implement explicit relational processing strategies rather than a fundamental deficit in the implicit activation and retrieval of word meanings from patients' semantic lexicon.

  17. Thermodynamic analysis of the process of formation of sulfur compounds in oxygen gasification of coal

    SciTech Connect

    G.Ya. Gerasimov; T.M. Bogacheva

    2001-05-15

    A thermodynamic approach to the description of the behavior of the system fuel-oxidizer in oxygen gasification of coal is used to reveal the main mechanisms of the process of capture of sulfur by the mineral part of the coal and to determine the fundamental possibility of the process for coals from different coal fields.

  18. The Importance of Analyzing Longitudinal Data in a Formative Evaluation Process: Applying Statistical Quality Control Techniques.

    ERIC Educational Resources Information Center

    Fraas, John W.; Newman, Isadore

    One may receive the most benefit from an evaluation of an educational program or the performance of a teacher if the evaluation process is approached from a Total Quality Management (TQM) point of view. Under the philosophy of TQM, the purpose of any evaluation process is to provide feedback for the continual improvement of the educational process…

  19. Influence of process conditions and water quality on the formation of mutagenic byproducts in UV/H2O2 processes.

    PubMed

    Hofman-Caris, Roberta C H M; Harmsen, Danny J H; Puijker, Leo; Baken, Kirsten A; Wols, Bas A; Beerendonk, E F; Keltjens, Leo L M

    2015-05-01

    UV/H2O2 processes in drinking water treatment may generate byproducts which cause an increased response in Ames fluctuation assays. As this probably involves a mixture of substances in very low concentrations, it is challenging to identify the individual byproducts. Therefore it was studied under which conditions mutagenic byproducts are formed and how this can be prevented. It was found that positive Ames fluctuation test responses only are obtained when Medium Pressure UV lamps are used, and not with Low Pressure lamps. This probably is explained by the photolysis of nitrate, which plays an important role in the formation of mutagenic byproducts. The most important parameters involved in the formation of such byproducts were demonstrated to be the nitrate concentration, the natural organic matter, the UV spectrum of the lamps, and the UV dose applied. These factors explain up to 74-87% of the Ames fluctuation test responses after UV/H2O2 drinking water treatment. By taking this into account, drinking water utilities can estimate whether UV processes applied in their case may cause the formation of mutagenic byproducts, and how to take measures to prevent it.

  20. Education and personalized genomics: deciphering the public's genetic health report

    PubMed Central

    Lamb, Neil E; Myers, Richard M; Gunter, Chris

    2010-01-01

    Where do members of the public turn to understand what genetic tests mean in terms of their own health? Now that genome-wide association studies and complete genome sequencing are widely available, the importance of education in personalized genomics cannot be overstated. Although some media have introduced the concept of genetic testing to better understand health and disease, the public's understanding of the scope and impact of genetic variation has not kept up with the pace of the science or technology. Unfortunately, the likely sources to which the public turn to for guidance – their physician and the media – are often no better prepared. We examine several venues for information, including print and online guides for both lay and health-oriented audiences, and summarize selected resources in multiple formats. We also note on the roadblocks to progress and discuss ways to remove them, as urgent action is needed to connect people with their genomes in a meaningful way. PMID:20161675

  1. Tectonic Activity and Processes Preceding the Formation of the Dead Sea Fault Zone

    NASA Astrophysics Data System (ADS)

    Eppelbaum, L. V.; Pilchin, A. N.

    2007-12-01

    Analysis of geological-geophysical data indicates that at the end of the Proterozoic, blocks of the Arabian Shield (AS) were thrust to the north-west onto the crust of the proto-Mediterranean (PM). This was caused by the pushing of oceanic crust from the south-east forming the Najd faults system (NF). This thrusting took place between 630 and 590 Ma, and is confirmed by the offsets between the Yanbu suture of the AS and Allaqi-Sol Hamid suture of the Nubian Shield (NS), the Bi'r Umq suture of AS and Nakasib suture of NS, and parts of the Yanbu and Nabitah sutures of AS. This caused the separation of AS from NS, and AS from the continental crust to north-east of it with its north-western displacement, resulting in opening of the Persian Gulf. This caused the start of deposition of huge amounts of Vendian-Cambrian evaporites in Saudi Arabia, Oman, Persian Gulf, Zagros, central Iran and other regions. The fact of the formation and preservation of the evaporites, and the common similarities in Vendian-Triassic sedimentary cover of Central Iran, Zagros, Taurus, and Arabian Plate (AP) and common Late Proterozoic-Early Paleozioc magmatic activity, show that these regions did not change their position significantly since then. Results of the DESERT project show that the lowermost part of the crust is present east of the Dead Sea Fault Zone (DSFZ), but it is absent west of it. This could be explained by detachment of the bottom part of the crust west of DSFZ during AP thrusting onto the crust of PM. The lithospheric slice discovered by seismic data between Moho and depth of about 55 km in S. Israel could be a remnant of that crust. During the thrusting, the AP overrode the detached slice. The slice was later remelted during formation of the postorogenic magmatic rocks of 590-530 Ma widespread in Jordan. The formation of three dyke swarms in S. Israel (600-540 Ma), widespread dykes in Sinai (590-530 Ma) and AP (590-530 Ma), as well as high-T-low-P metamorphism between 600

  2. Identification of indicators of groundwater quality formation process using a zoning model

    NASA Astrophysics Data System (ADS)

    Jing, Xiu-yan; Yang, Hongbin; Cao, Yuqing; Wang, Wenke

    2014-06-01

    Drinking water safety is a world-wide focus. In Yinchuan Plain of western China, groundwater is mostly saline water, and it has generated many problems for the life of local residents. Yinchuan Plain exhibits differences from the mountain area to the plain in terrain and elevation, and landforms and scales. Such differences resulted in hydro-geological water storage structures with different water yield properties and permeabilities of the aquifers. These water storage structures are the places where the groundwater moves and is retained, as well as where the air-water-rock interaction and the migration and differentiation between substances in the water take place. With the arid climate and intense irrigation in Yinchuan Plain, the hydro-chemical features of the groundwater exhibit distinct zonation. To explore the formative mechanism of the groundwater quality in Yinchuan Plain, a zoning model for the formation of groundwater quality is established in three layers, the first layer shows the geological and hydrogeological conditions that express the landform and landscape, geological age, lithology, and hydrodynamic features of the studied area. The second layer indicates the zonation of the formation of groundwater quality. According to the major hydro-geochemical actions, the plain is divided from west to east into lixiviation, evaporation, and evaporation-mixing zones. The third layer contains the hydrodynamic features that express the hydro-chemical type, salinity, and the contents of the major ions as well as trace elements fluorine and arsenic. The features of each zone are quantitatively expressed with thermodynamic, hydrodynamic, and hydro-chemical indicators.

  3. The connection between dark and baryonic matter in the process of galaxy formation

    NASA Astrophysics Data System (ADS)

    Trujillo, Sebastian

    2014-01-01

    Current galaxy formation theory still struggles to explain many essential galaxy properties. This thesis addresses these problems in the context of the interplay between baryons and dark matter in the concordance cosmological model. In the first part, we investigate galaxy abundance and scaling relations using a compilation of observational data along with large-scale cosmological simulations of dark matter (DM). We find that the standard cosmological model, in conjunction with halo abundance matching (HAM) and simple dynamical corrections, fits all basic statistics of galaxies more massive than the Large Magellanic Cloud (LMC). This zero-parameter model predicts the observed luminosity-velocity relation of early-and late-type galaxies, as well as the clustering of bright galaxies and the observed abundance of galaxies as a function of circular velocity. However, we find that all DM halos more massive than the LMC are much more abundant than the galaxies they host. Motivated by the model's shortcomings, in the second part we study the effect of baryons on galaxy formation using numerical simulations that include gas physics. We implement a model of star formation (SF) and stellar feedback based directly on observations of star-forming regions, where stellar feedback from massive stars includes radiation pressure, photoheating, supernovae, and stellar winds. We find that stellar radiation has a strong effect at z > 1, where it efficiently suppresses SF by dispersing cold and dense gas, preventing runaway growth of the stellar component, and yielding rising SF histories that reproduce many observations. Stellar feedback produces bulgeless discs with rotation curves and baryon fractions in excellent agreement with data. Feedback-driven blowouts reduce the central DM density of a dwarf, relieving tension between ACDM and observations. Based on these results, we begin to characterize the baryon cycle of galaxies and its imprint on studies of the circumgalactic medium

  4. COMBINING PROTEIN AND mRNA QUANTIFICATION TO DECIPHER TRANSCRIPTIONAL REGULATION

    PubMed Central

    Xu, Heng; Sepúlveda, Leonardo A.; Figard, Lauren; Sokac, Anna Marie; Golding, Ido

    2015-01-01

    We combine immunofluorescence and single-molecule fluorescence in situ hybridization (smFISH), followed by automated image analysis, to quantify the concentration of nuclear transcription factors, number of transcription factors bound, and number of nascent mRNAs synthesized at individual gene loci. A theoretical model is used to decipher how transcription-factor binding modulates the stochastic kinetics of mRNA production. We demonstrate this approach by examining the regulation of hunchback in the early Drosophila embryo. PMID:26098021

  5. Deciphering the Mechanism of Alternative Cleavage and Polyadenylation in Mantle Cell Lymphoma (MCL)

    DTIC Science & Technology

    2013-10-01

    Cleavage and Polyadenylation in Mantle Cell Lymphoma (MCL) PRINCIPAL INVESTIGATOR: Chioniso Masamha, Ph.D. CONTRACTING ORGANIZATION...CONTRACT NUMBER W81XWH-12-1-0218 Deciphering the Mechanism of Alternative Cleavage and Polyadenylation in Mantle Cell Lymphoma (MCL) 5b...shorten the 3’UTR of their mRNAs has important implications in cancer. Truncation of the cyclin D1 mRNA in mantle cell lymphoma (MCL) is one of the

  6. Computer simulation of the dynamic process of mark formation for magneto-optical memory

    NASA Astrophysics Data System (ADS)

    Hasegawa, Motoko; Moroga, Katsumi; Okada, Mitsuya; Okada, Osamu; Hidaka, Yasuharu

    1994-02-01

    A computer simulation method, based on the Landau-Lifshitz-Gilbert equation was developed in order to investigate the dynamics of magneto-optical recording and the mark writing process for the rare earth-transition metal amorphous magneto-optical layer was subsequently analyzed. It was found that the writing process depends sensitively on the spot radius of the irradiation laser. This result is discussed considering the reverse magnetized domain shrinking force, due to radial direction variation of wall energy density in a cylindrical domain model and the characteristics of the magnetic parameters. The writing process is especially affected by the temperature dependence of parameters in the region near the Curie temperature.

  7. Kinetic formation of (Bi,Pb)-2223 compound during the last stage of a multi-step thermal preparation process

    NASA Astrophysics Data System (ADS)

    M'chirgui, A.; Zouaoui, M.; Ben Azzouz, F.; Ben Saı̈d, M. A.; Smirani, R.; Ben Salem, M.

    2002-08-01

    A kinetic study of the (Bi,Pb)-2223 phase formation has been performed through a two-cycles annealing process at a temperature of 835°C by X-ray diffraction and SEM observations. Samples were Pb-doped (part 0.4 of Bi substituted by Pb) during the first thermal cycle. A second substantial addition of up to 10% excess of PbO in weight was added at the beginning of the second thermal cycle. PbO addition was shown to be more effective during the second cycle. Using the Avrami equation, a kinetic study of the (Bi,Pb)-2223 phase formation mechanism was conducted. The reaction order, n has been shown to depend on PbO excess and thus the (Bi,Pb)-2223 formation mechanism. With lower excess of PbO (0% and 4%), n is about 0.5 and the related formation mechanism corresponds to the thickening of plates after their edges have been impinged. With higher excess of PbO (10%), n is about 2,2 and the related mechanism corresponds to the initial growth of particles nucleated at a constant rate.

  8. The formation of low-temperature sedimentary pyrite and its relationship with biologically-induced processes

    NASA Astrophysics Data System (ADS)

    Cavalazzi, B.; Agangi, A.; Barbieri, R.; Franchi, F.; Gasparotto, G.

    2014-09-01

    This contribution is an updated review on sedimentary pyrite and on its role in well-consolidated research topics, such as the biogeochemical cycles and the studies on sediment-hosted ore deposit studies, as well as new frontiers of research, such as astrobiology. Textural and compositional information preserved in sedimentary pyrite from sediment-hosted ore deposits has contributed to elucidate their environment of forzmation. In particular, the content of redox-sensitive elements such as Ni, Co, Mo, and V has implications for defining the syn- and post-sedimentary conditions. In addition, the stable isotope compositions are useful indicators of the pathways of both biogenic and abiogenic pyrite formation. Despite the longstanding research on pyrite and the mechanism of its formation, there are still significant gaps in our knowledge. In this nonexhaustive review, we briefly touch on different current aspects of research on sedimentary pyrite, exemplifying how sedimentary pyrite remains relevant to geoscientists, and becomes more and more relevant in understanding some basic aspects of knowledge, such as the origin of life and the search for extraterrestrial life, as well as aspect of classical applied science, such as the implications for ore deposition.

  9. From landform to process: Morphology and formation of lake-bed barchan dunes, Makgadikgadi, Botswana

    NASA Astrophysics Data System (ADS)

    Burrough, Sallie L.; Thomas, David S. G.; Bailey, Richard M.; Davies, Lauren

    2012-08-01

    A suite of crescentic landforms is visible from remotely sensed imagery within the Ntwetwe panPan in the Makgadikgadi basin, Botswana. We investigate the most distinct of these landforms using morphometric measurements, sedimentary data and Optically Stimulated Luminescence (OSL) signal analysis. Comparative analysis with previously published barchan morphological data sets suggest the Ntwetwe features fall within the spectrum of morphometric parameters found in a range of barchan dunefields from around the world. There is currently insufficient comparative morphometric data from sub-aqueous dunefields to be able to distinguish the particular formative environment of the dune. OSL signal analyses however, support the hypothesis of Grove (1969) [Grove, A.T., 1969. Landforms and climatic change in the Kalahari and Ngamiland. Geographical Journal, 135: 191-212] that the last deposition of the sediments within the Ntwetwe forms was most likely aeolian in origin. Luminescence signal analysis is employed to investigate potential transport and bleaching environments of the sediments forming the features, but results in this case do not shed further light on the formative conditions of these enigmatic landforms.

  10. Modeling the Formation Process of Grouping Stimuli Sets through Cortical Columns and Microcircuits to Feature Neurons

    PubMed Central

    Williamson, Adam

    2013-01-01

    A computational model of a self-structuring neuronal net is presented in which repetitively applied pattern sets induce the formation of cortical columns and microcircuits which decode distinct patterns after a learning phase. In a case study, it is demonstrated how specific neurons in a feature classifier layer become orientation selective if they receive bar patterns of different slopes from an input layer. The input layer is mapped and intertwined by self-evolving neuronal microcircuits to the feature classifier layer. In this topical overview, several models are discussed which indicate that the net formation converges in its functionality to a mathematical transform which maps the input pattern space to a feature representing output space. The self-learning of the mathematical transform is discussed and its implications are interpreted. Model assumptions are deduced which serve as a guide to apply model derived repetitive stimuli pattern sets to in vitro cultures of neuron ensembles to condition them to learn and execute a mathematical transform. PMID:24369455

  11. Modeling the formation process of grouping stimuli sets through cortical columns and microcircuits to feature neurons.

    PubMed

    Klefenz, Frank; Williamson, Adam

    2013-01-01

    A computational model of a self-structuring neuronal net is presented in which repetitively applied pattern sets induce the formation of cortical columns and microcircuits which decode distinct patterns after a learning phase. In a case study, it is demonstrated how specific neurons in a feature classifier layer become orientation selective if they receive bar patterns of different slopes from an input layer. The input layer is mapped and intertwined by self-evolving neuronal microcircuits to the feature classifier layer. In this topical overview, several models are discussed which indicate that the net formation converges in its functionality to a mathematical transform which maps the input pattern space to a feature representing output space. The self-learning of the mathematical transform is discussed and its implications are interpreted. Model assumptions are deduced which serve as a guide to apply model derived repetitive stimuli pattern sets to in vitro cultures of neuron ensembles to condition them to learn and execute a mathematical transform.

  12. Simulation of geochemical processes responsible for the formation of the Zhezqazghan deposit

    NASA Astrophysics Data System (ADS)

    Ryzhenko, B. N.; Cherkasova, E. V.

    2014-05-01

    Physicochemical computer simulation of water-rock systems at a temperature of 25-150°C and under a pressure of up to 600 bar has been carried out for quantitative description of the mineralization formation conditions at sandstone- and shale-hosted copper deposits. The simulation is based on geological and geochemical information concerning the Zhezqazghan deposit and considers (i) a source of ore matter, (ii) composition of the fluid that transfers ore matter to the ore formation zone, and (iii) factors of ore concentration. It has been shown that extraction of copper from minerals of rocks and its accumulation in aqueous solution are optimal at a high mass ratio of rock to water (R/W > 10), Eh of +200 to -100 mV, and an obligatory content of chloride ions in the aqueous phase. The averaged ore-bearing fluid Cl95SO44//Ca50(Na + K)30Mg19 (eq %), pH ˜ 4, mineralization of up to 400 g/L, is formed by the interaction of red sandstone beds with a sedimentogenic brine (a product of metamorphism of seawater in carbonate rocks enriched in organic matter). The ore concentration proceeds in the course of cooling from 150 to 50°C during filtration of ore-bearing fluid through red sandstone beds in the rock-water system thermodynamically opened with respect to the reductive components.

  13. Influence of the brewing process on furfuryl ethyl ether formation during beer aging.

    PubMed

    Vanderhaegen, Bart; Neven, Hedwig; Verstrepen, Kevin J; Delvaux, Freddy R; Verachtert, Hubert; Derdelinckx, Guy

    2004-11-03

    In beer, the development of a solvent-like stale flavor is associated with the formation of furfuryl ethyl ether. The synthesis rate of this important flavor compound is proportional to the concentration of furfuryl alcohol in beer. This study shows that furfuryl alcohol in beer is mainly formed by Maillard reactions initiated during wort boiling and malt production. A mechanism for its formation from alpha-(1,4)-oligoglucans and amino acids in wort and beer is proposed. During wort boiling, a quadratic relationship was found between the wort extract concentration, on the one hand, and the increase of furfuryl alcohol and furfural, on the other. The reduction of furfural by yeast during fermentation further increases the furfuryl alcohol content. In pale beers, the furfuryl alcohol concentration is essentially determined by the thermal load on wort during brewing operations. In dark beers, a considerable fraction of furfuryl alcohol may, however, come from the dark malts used. These results lead to important practical conclusions concerning the control over furfuryl ethyl ether in beer.

  14. Inhibitory effect of glutamic acid on the scale formation process using electrochemical methods.

    PubMed

    Karar, A; Naamoune, F; Kahoul, A; Belattar, N

    2016-08-01

    The formation of calcium carbonate CaCO3 in water has some important implications in geoscience researches, ocean chemistry studies, CO2 emission issues and biology. In industry, the scaling phenomenon may cause technical problems, such as reduction in heat transfer efficiency in cooling systems and obstruction of pipes. This paper focuses on the study of the glutamic acid (GA) for reducing CaCO3 scale formation on metallic surfaces in the water of Bir Aissa region. The anti-scaling properties of glutamic acid (GA), used as a complexing agent of Ca(2+) ions, have been evaluated by the chronoamperometry and electrochemical impedance spectroscopy methods in conjunction with a microscopic examination. Chemical and electrochemical study of this water shows a high calcium concentration. The characterization using X-ray diffraction reveals that while the CaCO3 scale formed chemically is a mixture of calcite, aragonite and vaterite, the one deposited electrochemically is a pure calcite. The effect of temperature on the efficiency of the inhibitor was investigated. At 30 and 40°C, a complete scaling inhibition was obtained at a GA concentration of 18 mg/L with 90.2% efficiency rate. However, the efficiency of GA decreased at 50 and 60°C.

  15. Time to Translate: Deciphering the Codon in the Classroom

    ERIC Educational Resources Information Center

    Firooznia, Fardad

    2015-01-01

    I describe and evaluate a fun and simple role-playing exercise that allows students to actively work through the process of translation. This exercise can easily be completed during a 50-minute class period, with time to review the steps and contemplate complications such as the effects of various types of mutations.

  16. 47 CFR 11.56 - Obligation to process CAP-formatted EAS messages.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... and EAS Header Codes, audio Attention Signal, audio message, and Preamble and EAS End of Message (EOM... voluntary basis). (3) Processing such converted messages in accordance with the other sections of this...

  17. A Study on Reactive Spray Deposition Technology Processing Parameters in the Context of Pt Nanoparticle Formation

    NASA Astrophysics Data System (ADS)

    Roller, Justin M.; Maric, Radenka

    2015-12-01

    Catalytic materials are complex systems in which achieving the desired properties (i.e., activity, selectivity and stability) depends on exploiting the many degrees of freedom in surface and bulk composition, geometry, and defects. Flame aerosol synthesis is a process for producing nanoparticles with ample processing parameter space to tune the desired properties. Flame dynamics inside the reactor are determined by the input process variables such as solubility of precursor in the fuel; solvent boiling point; reactant flow rate and concentration; flow rates of air, fuel and the carrier gas; and the burner geometry. In this study, the processing parameters for reactive spray deposition technology, a flame-based synthesis method, are systematically evaluated to understand the residence times, reactant mixing, and temperature profiles of flames used in the synthesis of Pt nanoparticles. This provides a framework for further study and modeling. The flame temperature and length are also studied as a function of O2 and fuel flow rates.

  18. Development of metallization process. FSA project, cell and module formation research area

    NASA Technical Reports Server (NTRS)

    Garcia, A., III

    1984-01-01

    New pastes were evaluated that contained additives to aid in the silicon-to-metallization contact. None were completely successful. A reevaluation of the molybdenum oxide paste and the two-step screen printing process was done. The oxide paste did not show promise. The two-step process enabled soldering of the cells but the cells still had a high series resistance. Pastes are on order from a different manufacturer.

  19. Semantic processes leading to true and false memory formation in schizophrenia

    PubMed Central

    Paz-Alonso, Pedro M.; Ghetti, Simona; Ramsay, Ian; Solomon, Marjorie; Yoon, Jong; Carter, Cameron S.; Ragland, J. Daniel

    2013-01-01

    Encoding semantic relationships between items on word lists (semantic processing) enhances true memories, but also increases memory distortions. Episodic memory impairments in schizophrenia (SZ) are strongly driven by failures to process semantic relations, but the exact nature of these relational semantic processing deficits are not well understood. Here, we used a false memory paradigm to investigate the impact of implicit and explicit semantic processing manipulations on episodic memory in SZ. Thirty SZ and 30 demographically matched healthy controls (HC) studied Deese/Roediger-McDermott (DRM) lists of semantically associated words. Half of the lists had strong implicit semantic associations and the remainder had low strength associations. Similarly, half of the lists were presented under “standard” instructions and the other half under explicit “relational processing” instructions. After study, participants performed recall and old/new recognition tests composed of targets, critical lures, and unrelated lures. HC exhibited higher true memories and better discriminability between true and false memory compared to SZ. High, versus low, associative strength increased false memory rates in both groups. However, explicit “relational processing” instructions positively improved true memory rates only in HC. Finally, true and false memory rates were associated with severity of disorganized and negative symptoms in SZ. These results suggest that reduced processing of semantic relationships during encoding in SZ may stem from an inability to implement explicit relational processing strategies rather than a fundamental deficit in the implicit activation and retrieval of word meanings from patients’ semantic lexicon. PMID:23623175

  20. Modeling the relative contributions of secondary ice formation processes to ice crystal number concentrations within mixed-phase clouds

    NASA Astrophysics Data System (ADS)

    Sullivan, Sylvia; Hoose, Corinna; Nenes, Athanasios

    2016-04-01

    Measurements of in-cloud ice crystal number concentrations can be three or four orders of magnitude greater than the in-cloud ice nuclei number concentrations. This discrepancy can be explained by various secondary ice formation processes, which occur after initial ice nucleation, but the relative importance of these processes, and even the exact physics of each, is still unclear. A simple bin microphysics model (2IM) is constructed to investigate these knowledge gaps. 2IM extends the time-lag collision parameterization of Yano and Phillips, 2011 to include rime splintering, ice-ice aggregation, and droplet shattering and to incorporate the aspect ratio evolution as in Jensen and Harrington, 2015. The relative contribution of the secondary processes under various conditions are shown. In particular, temperature-dependent efficiencies are adjusted for ice-ice aggregation versus collision around -15°C, when rime splintering is no longer active, and the effect of aspect ratio on the process weighting is explored. The resulting simulations are intended to guide secondary ice formation parameterizations in larger-scale mixed-phase cloud schemes.

  1. Peat Formation Processes Through the Millennia in Tidal Marshes of the Sacramento-San Joaquin Delta, California, USA

    USGS Publications Warehouse

    Drexler, J.Z.

    2011-01-01

    The purpose of this study was to determine peat formation processes throughout the millennia in four tidal marshes in the Sacramento-San Joaquin Delta. Peat cores collected at each site were analyzed for bulk density, loss on ignition, and percent organic carbon. Core data and spline fit age-depth models were used to estimate inorganic sedimentation, organic accumulation, and carbon sequestration rates in the marshes. Bulk density and percent organic matter content of peat fluctuated through time at all sites, suggesting that peat formation processes are dynamic and responsive to watershed conditions. The balance between inorganic sedimentation and organic accumulation at the sites also varied through time, indicating that marshes may rely more strongly on either inorganic or organic matter for peat formation at particular times in their existence. Mean carbon sequestration rates found in this study (0. 38-0. 79 Mg C ha-1 year-1) were similar to other long-term estimates for temperate peatlands. ?? 2011 Coastal and Estuarine Research Federation (outside the USA).

  2. Electroporation-induced formation of individual calcium entry sites in the cell body and processes of adherent cells.

    PubMed Central

    Teruel, M N; Meyer, T

    1997-01-01

    Electroporation is a widely used method for introducing macromolecules into cells. We developed an electroporation device that requires only 1 microl of sample to load adherent cells in a 10-mm2 surface area while retaining greater than 90% cell survivability. To better understand this device, field-induced permeabilization of adherent rat basophilic leukemia and neocortical neuroblastoma cells was investigated by using fluorescent calcium and voltage indicators. Rectangular field pulses led to the formation of only a few calcium entry sites, preferentially in the hyperpolarized parts of the cell body and processes. Individual entry sites were formed at the same locations when field pulses were repeated. Before calcium entry, a partial breakdown of the membrane potential was observed in both polar regions. Based on our results, a model is proposed for the formation and closure of macromolecule entry sites in adherent cells. First, the rapid formation of a large number of small pores leads to a partial membrane potential breakdown in both polar regions of the cell. Second, over tens of milliseconds, a few entry sites for macromolecules are formed, preferentially in the hyperpolarized part of cell body and processes, at locations defined by the local membrane structure. These entry sites reseal on a time scale of 50 ms to several seconds, with residual small pores remaining open for several minutes. Images FIGURE 1 FIGURE 2 FIGURE 3 FIGURE 4 FIGURE 5 FIGURE 6 FIGURE 8 FIGURE 9 PMID:9336174

  3. Photodegradation kinetics of iopamidol by UV irradiation and enhanced formation of iodinated disinfection by-products in sequential oxidation processes.

    PubMed

    Tian, Fu-Xiang; Xu, Bin; Lin, Yi-Li; Hu, Chen-Yan; Zhang, Tian-Yang; Gao, Nai-Yun

    2014-07-01

    The photochemical degradation of iopamidol with low-pressure UV lamps and the formation of iodinated disinfection by-products (I-DBPs) during sequential oxidation processes including chlorine, monochloramine and chlorine dioxide were investigated in this study. Iopamidol can be effectively decomposed by UV irradiation with pseudo-first order reaction kinetics. The evaluated quantum yield was found to be 0.03318 mol einstein(-1). Results showed that iopamidol degradation rate was significantly increased by higher UV intensity and lower initial iopamidol concentration. However, the effect of solution pH was negligible. Degradation of iopamidol by UV photolysis was subjected to deiodination and hydroxylation mechanisms. The main degradation products including -OH substitutes and iodide were identified by UPLC-ESI-MS and UPLC-UV, respectively. Increasing the intensity of UV irradiation promoted the release of iodide. Destruction pathways of iopamidol photolysis were proposed. Enhanced formation of I-DBPs were observed after iopamidol photolysis followed by disinfection processes including chlorine, monochloramine and chlorine dioxide. With the increase of UV fluence, I-DBPs formation were significantly promoted.

  4. Satellite observations and EMAC model calculations of sulfate aerosols from Kilauea: a study of aerosol formation, processing, and loss

    NASA Astrophysics Data System (ADS)

    Penning de Vries, Marloes; Beirle, Steffen; Brühl, Christoph; Dörner, Steffen; Pozzer, Andrea; Wagner, Thomas

    2016-04-01

    The currently most active volcano on Earth is Mount Kilauea on Hawaii, as it has been in a state of continuous eruption since 1983. The opening of a new vent in March 2008 caused half a year of strongly increased SO2 emissions, which in turn led to the formation of a sulfate plume with an extent of at least two thousand kilometers. The plume could be clearly identified from satellite measurements from March to November, 2008. The steady trade winds in the region and the lack of interfering sources allowed us to determine the life time of SO2 from Kilauea using only satellite-based measurements (no a priori or model information). The current investigation focuses on sulfate aerosols: their formation, processing and subsequent loss. Using space-based aerosol measurements by MODIS, we study the evolution of aerosol optical depth, which first increases as a function of distance from the volcano due to aerosol formation from SO2 oxidation, and subsequently decreases as aerosols are deposited to the surface. The outcome is compared to results from calculations using the EMAC (ECHAM/MESSy Atmospheric Chemistry) model to test the state of understanding of the sulfate aerosol life cycle. For this comparison, a particular focus is on the role of clouds and wet removal processes.

  5. Deciphering Halogen Competition in Organometallic Halide Perovskite Growth

    DOE PAGES

    Keum, Jong Kahk; Ovchinnikova, Olga S.; Chen, Shiyou; ...

    2016-03-01

    Organometallic halide perovskites (OHPs) hold great promise for next-generation, low-cost optoelectronic devices. During the chemical synthesis and crystallization of OHP thin films a major unresolved question is the competition between multiple halide species (e.g. I-, Cl-, Br-) in the formation of the mixed halide perovskite crystals. Whether Cl- ions are successfully incorporated into the perovskite crystal structure or alternatively, where they are located, is not yet fully understood. Here, in situ X-ray diffraction measurements of crystallization dynamics are combined with ex situ TOF-SIMS chemical analysis to reveal that Br- or Cl- ions can promote crystal growth, yet reactive I- ionsmore » prevent them from incorporating into the lattice of the final perovskite crystal structure. The Cl- ions are located in the grain boundaries of the perovskite films. These findings significantly advance our understanding of the role of halogens during synthesis of hybrid perovskites, and provide an insightful guidance to the engineering of high-quality perovskite films, essential for exploring superior-performance and cost-effective optoelectronic devices.« less

  6. Deciphering Halogen Competition in Organometallic Halide Perovskite Growth

    SciTech Connect

    Keum, Jong Kahk; Ovchinnikova, Olga S.; Chen, Shiyou; Du, Mao-Hua; Ivanov, Ilia N; Rouleau, Christopher; Geohegan, David B.; Xiao, Kai

    2016-03-01

    Organometallic halide perovskites (OHPs) hold great promise for next-generation, low-cost optoelectronic devices. During the chemical synthesis and crystallization of OHP thin films a major unresolved question is the competition between multiple halide species (e.g. I-, Cl-, Br-) in the formation of the mixed halide perovskite crystals. Whether Cl- ions are successfully incorporated into the perovskite crystal structure or alternatively, where they are located, is not yet fully understood. Here, in situ X-ray diffraction measurements of crystallization dynamics are combined with ex situ TOF-SIMS chemical analysis to reveal that Br- or Cl- ions can promote crystal growth, yet reactive I- ions prevent them from incorporating into the lattice of the final perovskite crystal structure. The Cl- ions are located in the grain boundaries of the perovskite films. These findings significantly advance our understanding of the role of halogens during synthesis of hybrid perovskites, and provide an insightful guidance to the engineering of high-quality perovskite films, essential for exploring superior-performance and cost-effective optoelectronic devices.

  7. Deciphering the Multifactorial Nature of Acinetobacter baumannii Pathogenicity

    PubMed Central

    Antunes, Luísa C. S.; Imperi, Francesco; Carattoli, Alessandra; Visca, Paolo

    2011-01-01

    Background Acinetobacter baumannii is an emerging bacterial pathogen that causes a broad array of infections, particularly in hospitalized patients. Many studies have focused on the epidemiology and antibiotic resistance of A. baumannii, but little is currently known with respect to its virulence potential. Methodology/Principal Findings The aim of this work was to analyze a number of virulence-related traits of four A. baumannii strains of different origin and clinical impact for which complete genome sequences were available, in order to tentatively identify novel determinants of A. baumannii pathogenicity. Clinical strains showed comparable virulence in the Galleria mellonella model of infection, irrespective of their status as outbreak or sporadic strains, whereas a non-human isolate was avirulent. A combined approach of genomic and phenotypic analyses led to the identification of several virulence factors, including exoproducts with hemolytic, phospholipase, protease and iron-chelating activities, as well as a number of multifactorial phenotypes, such as biofilm formation, surface motility and stress resistance, which were differentially expressed and could play a role in A. baumannii pathogenicity. Conclusion/Significance This work provides evidence of the multifactorial nature of A. baumannii virulence. While A. baumannii clinical isolates could represent a selected population of strains adapted to infect the human host, subpopulations of highly genotypically and phenotypically diverse A. baumannii strains may exist outside the hospital environment, whose relevance and distribution deserve further investigation. PMID:21829642

  8. Silk Fibroin-Sophorolipid Gelation: Deciphering the Underlying Mechanism.

    PubMed

    Dubey, Parul; Kumar, Sugam; Aswal, Vinod K; Ravindranathan, Sapna; Rajamohanan, Pattuparambil R; Prabhune, Asmita; Nisal, Anuya

    2016-10-10

    Silk fibroin (SF) protein, produced by silkworm Bombyx mori, is a promising biomaterial, while sophorolipid (SL) is an amphiphilic functional biosurfactant synthesized by nonpathogenic yeast Candida bombicola. SL is a mixture of two forms, acidic (ASL) and lactonic (LSL), which when added to SF results in accelerated gelation of silk fibroin. LSL is known to have multiple biological functionalities and hence hydrogels of these green molecules have promising applications in the biomedical sector. In this work, SANS, NMR, and rheology are employed to examine the assembling properties of individual and mixed SLs and their interactions with SF to understand the mechanism that leads to rapid gelation. SANS and NMR studies show that ASL assembles to form charged micelles, while LSL forms micellar assemblies and aggregates of a mass fractal nature. ASL and LSL together form larger mixed micelles, all of which interact differently with SF. It is shown that preferential binding of LSL to SF causes rapid unfolding of the SF chain leading to the formation of intermolecular beta sheets, which trigger fast gelation. Based on the observations, a mechanism for gelation of SF in the presence of different sophorolipids is proposed.

  9. Deciphering the mechanism underlying late-onset Alzheimer disease.

    PubMed

    Krstic, Dimitrije; Knuesel, Irene

    2013-01-01

    Despite tremendous investments in understanding the complex molecular mechanisms underlying Alzheimer disease (AD), recent clinical trials have failed to show efficacy. A potential problem underlying these failures is the assumption that the molecular mechanism mediating the genetically determined form of the disease is identical to the one resulting in late-onset AD. Here, we integrate experimental evidence outside the 'spotlight' of the genetic drivers of amyloid-β (Aβ) generation published during the past two decades, and present a mechanistic explanation for the pathophysiological changes that characterize late-onset AD. We propose that chronic inflammatory conditions cause dysregulation of mechanisms to clear misfolded or damaged neuronal proteins that accumulate with age, and concomitantly lead to tau-associated impairments of axonal integrity and transport. Such changes have several neuropathological consequences: focal accumulation of mitochondria, resulting in metabolic impairments; induction of axonal swelling and leakage, followed by destabilization of synaptic contacts; deposition of amyloid precursor protein in swollen neurites, and generation of aggregation-prone peptides; further tau hyperphosphorylation, ultimately resulting in neurofibrillary tangle formation and neuronal death. The proposed sequence of events provides a link between Aβ and tau-related neuropathology, and underscores the concept that degenerating neurites represent a cause rather than a consequence of Aβ accumulation in late-onset AD.

  10. Appropriate deposition parameters for formation of fcc Co-Ni alloy nanowires during electrochemical deposition process

    NASA Astrophysics Data System (ADS)

    Mukhtar, Aiman; Shahzad Khan, Babar; Mehmood, Tahir

    2016-12-01

    The effect of deposition potential on the crystal structure and composition of Co-Ni alloy nanowires is studied by XRD, FE-SEM and EDX. The alloy nanowires deposited at -3.2 V are metastable fcc phase Co-Ni. The alloy nanowires deposited at -1.8 V are hcp phase Co-Ni. The formation of the metastable fcc alloy nanowires can be attributed to smaller critical clusters formed at the high potential as the smaller critical clusters favor fcc structure because of the significant surface energy effect. The content of Co inside nanowires increases with increasing potential. This can be understood by the polarization curves of depositing Co and Ni nanowires, which show that the current density ratio of Ni to Co at low potential has larger value than that at high potential.

  11. Formation of serrated nanorods of hydroxyapatite through organic modification under hydrothermal processing

    NASA Astrophysics Data System (ADS)

    Prakash Parthiban, S.; Kim, Ill Yong; Kikuta, Koichi; Ohtsuki, Chikara

    2013-06-01

    Hydroxyapatite (HAp) ceramics are widely used as artificial bone substitutes owing to its unique biological activity, that is, bone-bonding property. HAp nanoparticles have higher potential of biological functionality than microparticles owing to their increased specific surface area (SSA) because biological functionality of the crystals is governed by their surface characteristics. HAp particles of varied size and morphology have been prepared by employing various kinds of surfactants and capping ligands. In this research, we report the formation of HAp nanorods with serrated morphology which led to an increase in SSA. We obtained HAp nanorods with serrated morphology by adding thiosalicylic acid as a capping ligand under hydrothermal conditions. The tailoring of HAp nanorods by thiosalicylic acid under hydrothermal conditions is a useful method to prepare HAp nanorods with improved functionality.

  12. Grain formation in astronomical systems: A critical review of condensation processes

    NASA Technical Reports Server (NTRS)

    Donn, B.

    1978-01-01

    An analysis is presented of the assumption and the applicability of the three theoretical methods for calculating condensations in cosmic clouds where no pre-existing nuclei exist. The three procedures are: thermodynamic equilibrium calculations, nucleation theory, and a kinetic treatment which would take into account the characteristics of each individual collision. Thermodynamics provide detailed results on the composition temperature and composition of the condensate provided the system attains equilibrium. Because of the cosmic abundance mixture of elements, large supersaturations in some cases and low pressures, equilibrium is not expected in astronomical clouds. Nucleation theory, a combination of thermodynamics and kinetics, has the limitations of each scheme. Kinetics, not requiring equilibrium, avoids nearly all the thermodynamics difficulties but requires detailed knowledge of many reactions which thermodynamics avoids. It appears to be the only valid way to treat grain formation in space. A review of experimental studies is given.

  13. Effect of processing conditions of dicalcium phosphate cements on graft resorption and bone formation.

    PubMed

    Sheikh, Zeeshan; Zhang, Yu Ling; Tamimi, Faleh; Barralet, Jake

    2017-02-15

    Dicalcium phosphate cements (brushite and monetite) are resorbable biomaterials with osteoconductive potential for bone repair and regeneration that have yet to gain widespread commercial use. Brushite can be converted to monetite by heat treatments additionally resulting in various changes in the physico-chemical properties. However, since conversion is most commonly performed using autoclave sterilisation (wet heating), it is uncertain whether the properties observed for monetite as a result of heating brushite under dry conditions affect resorption and bone formation favourably. This study was designed to produce monetite grafts of differing physical form by autoclaving and dry heating (under vacuum) to be compared with brushite biomaterials in an orthotopic pre-clinical implantation model in rabbit for 12weeks. It was observed that monetite grafts had higher porosity and specific surface area than their brushite precursors. The autoclaved monetite grafts had compressive strength reduced by 50% when compared with their brushite precursors. However, the dry heat converted monetite grafts had compressive strength comparable with brushite. Results from in vivo experiments revealed that both types of monetite graft materials resorbed faster than brushite and more bone formation was achieved. There was no significant difference in the amount of bone formed between the two types of monetite grafts. The implanted brushite grafts underwent phase transformation to form hydroxyapatite, which ultimately limited bioresorption. However, this was not observed in both types of monetite grafts. In summary, both autoclaving and dry heating the preset brushite cement grafts resulted in monetite biomaterials which were more resorbable with potential to be investigated and optimized for orthopaedic and maxillofacial bone repair and regeneration applications.

  14. A quantitative approach to understanding amphibole reaction rims: Texture, mineralogy, and processes of formation

    NASA Astrophysics Data System (ADS)

    De Angelis, S. H.; Larsen, J. F.; Coombs, M. L.; Dunn, A.

    2012-12-01

    Amphibole is an important mineral present in many calc-alkaline volcanic deposits. A hydrous phase, volcanic amphibole is only stable at pressures greater than 100 MPa (approx. 4 km) and in melts containing at least 4 wt % H2O. When removed from their thermal and barometric stability field, amphiboles decompose to form aggregate rims of anhydrous minerals. Reaction rim thicknesses have been used to estimate timescales and rates of magma ascent, important parameters in determining eruptive style. However, the textures and mineralogy of reaction rims are complex; multiple forcing factors, such as heating and decompression, are responsible for their formation. Few studies have performed in-depth, systematic, and quantitative investigations of reaction rim textures and mineralogy: as a result, amphibole reaction rims are poorly understood. Based on natural reaction rims from Augustine Volcano Alaska, we have developed a new crystallization kinetics model for reaction rim formation in which the differences in reaction rim textures represent different degrees of forcing away from equilibrium. We present the results of an experimental study used to test this model. We performed experiments using a sintered high-silica andesite glass from the 2006 eruption of Augustine volcano. The starting powder was seeded with unrimmed amphibole phenocrysts. After at least 24 hours of equilibration at Augustine storage conditions (140 MPa/ 860oC), experiments were heated or decompressed. The experimental series experiments took samples to differing degrees of thermal of barometric instability, over different time scales, ranging from 3 hours to several days. The resulting reaction rims were analyzed using a variety of analytical imaging and X-ray mapping techniques. Reaction rims thickened and became more texturally and mineralogically complex as a result of 1) greater time spent outside of stability and; 2) the magnitude of instability experienced.

  15. Shear-Induced Amyloid Formation in the Brain: I. Potential Vascular and Parenchymal Processes

    PubMed Central

    Trumbore, Conrad N.

    2016-01-01

    Shear distortion of amyloid-beta (Aβ) solutions accelerates amyloid cascade reactions that may yield different toxic oligomers than those formed in quiescent solutions. Recent experiments indicate that cerebrospinal fluid (CSF) and interstitial fluid (ISF) containing Aβ flow through narrow brain perivascular pathways and brain parenchyma. This paper suggests that such flow causes shear distortion of Aβ molecules involving conformation changes that may be one of the initiating events in the etiology of Alzheimer’s disease. Aβ shearing can occur in or around brain arteries and arterioles and is suggested as the origin of cerebral amyloid angiopathy deposits in cerebrovascular walls. Comparatively low flow rates of ISF within the narrow extracellular spaces (ECS) of the brain parenchyma are suggested as a possible initiating factor in both the formation of neurotoxic Aβ42 oligomers and amyloid fibrils. Aβ42 in slow-flowing ISF can gain significant shear energy at or near the walls of tortuous brain ECS flow paths, promoting the formation of a shear-distorted, excited state hydrophobic Aβ42* conformation. This Aβ42* molecule could possibly be involved in one of two paths, one involving rapid adsorption to a brain membrane surface, ultimately forming neurotoxic oligomers on membranes, and the other ultimately forming plaque within the ECS flow pathways. Rising Aβ concentrations combined with shear at or near critical brain membranes are proposed as contributing factors to Alzheimer’s disease neurotoxicity. These hypotheses may be applicable in other neurodegenerative diseases, including tauopathies and alpha-synucleinopathies, in which shear-distorted proteins also may form in the brain ECS. PMID:27567812

  16. Shear-Induced Amyloid Formation in the Brain: I. Potential Vascular and Parenchymal Processes.

    PubMed

    Trumbore, Conrad N

    2016-09-06

    Shear distortion of amyloid-beta (Aβ) solutions accelerates amyloid cascade reactions that may yield different toxic oligomers than those formed in quiescent solutions. Recent experiments indicate that cerebrospinal fluid (CSF) and interstitial fluid (ISF) containing Aβ flow through narrow brain perivascular pathways and brain parenchyma. This paper suggests that such flow causes shear distortion of Aβ molecules involving conformation changes that may be one of the initiating events in the etiology of Alzheimer's disease. Aβ shearing can occur in or around brain arteries and arterioles and is suggested as the origin of cerebral amyloid angiopathy deposits in cerebrovascular walls. Comparatively low flow rates of ISF within the narrow extracellular spaces (ECS) of the brain parenchyma are suggested as a possible initiating factor in both the formation of neurotoxic Aβ42 oligomers and amyloid fibrils. Aβ42 in slow-flowing ISF can gain significant shear energy at or near the walls of tortuous brain ECS flow paths, promoting the formation of a shear-distorted, excited state hydrophobic Aβ42* conformation. This Aβ42* molecule could possibly be involved in one of two paths, one involving rapid adsorption to a brain membrane surface, ultimately forming neurotoxic oligomers on membranes, and the other ultimately forming plaque within the ECS flow pathways. Rising Aβ concentrations combined with shear at or near critical brain membranes are proposed as contributing factors to Alzheimer's disease neurotoxicity. These hypotheses may be applicable in other neurodegenerative diseases, including tauopathies and alpha-synucleinopathies, in which shear-distorted proteins also may form in the brain ECS.

  17. Bioactive glasses with improved processing. Part 1. Thermal properties, ion release and apatite formation.

    PubMed

    Groh, Daniel; Döhler, Franziska; Brauer, Delia S

    2014-10-01

    Bioactive glasses, particularly Bioglass® 45S5, have been used to clinically regenerate human bone since the mid-1980s; however, they show a strong tendency to undergo crystallization upon heat treatment, which limits their range of applications. Attempts at improving their processing (by reducing their tendency to crystallize) have included increasing their silica content (and thus their network connectivity), incorporating intermediate oxides or reducing their phosphate content, all of which reduce glass bioactivity. Therefore, bioactive glasses known for their good processing (e.g. 13-93) are considerably less bioactive. Here, we investigated if the processing of 45S5 bioactive glass can be improved while maintaining its network connectivity and phosphate content. The results show that, by increasing the calcium:alkali cation ratio, partially substituting potassium for sodium (thereby making use of the mixed alkali effect) and adding small amounts of fluoride, bioactive glasses can be obtained which have a larger processing window (suggesting that they can be processed more easily, allowing for sintering of scaffolds or drawing into fibres) while degrading readily and forming apatite in aqueous solution within a few hours.

  18. Effect of cooking temperature on the percentage colour formation, nitrite decomposition and sarcoplasmic protein denaturation in processed meat products.

    PubMed

    Okayama, T; Fujii, M; Yamanoue, M

    1991-01-01

    The effect of cooking temperature and time on the percentage colour formation, nitrite decomposition and denaturation of sarcoplasmic proteins in processed meat products was investigated in detail. The colour forming percentage increased with a rise in temperature of heating, especially at 50-60°C (P < 0·05). The percentage nitrite decomposition was promoted by the retention time of cooking rather than by the cooking temperature (P < 0·05). The percentage of sarcoplasmic proteins denatured was enhanced by heating temperature in the range 50-80°C (especially at 50-60°C) (P < 0·05). The relationship between the percentage colour formation and the percentage of sarcoplasmic proteins denatured is discussed. The SDS-PAGE patterns of the heat-treated samples revealed the components of the sarcoplasmic proteins which had been denatured.

  19. Real-time nonlinear feedback control of pattern formation in (bio)chemical reaction-diffusion processes: a model study.

    PubMed

    Brandt-Pollmann, U; Lebiedz, D; Diehl, M; Sager, S; Schlöder, J

    2005-09-01

    Theoretical and experimental studies related to manipulation of pattern formation in self-organizing reaction-diffusion processes by appropriate control stimuli become increasingly important both in chemical engineering and cellular biochemistry. In a model study, we demonstrate here exemplarily the application of an efficient nonlinear model predictive control (NMPC) algorithm to real-time optimal feedback control of pattern formation in a bacterial chemotaxis system modeled by nonlinear partial differential equations. The corresponding drift-diffusion model type is representative for many (bio)chemical systems involving nonlinear reaction dynamics and nonlinear diffusion. We show how the computed optimal feedback control strategy exploits the system inherent physical property of wave propagation to achieve desired control aims. We discuss various applications of our approach to optimal control of spatiotemporal dynamics.

  20. Real-time nonlinear feedback control of pattern formation in (bio)chemical reaction-diffusion processes: A model study

    NASA Astrophysics Data System (ADS)

    Brandt-Pollmann, U.; Lebiedz, D.; Diehl, M.; Sager, S.; Schlöder, J.

    2005-09-01

    Theoretical and experimental studies related to manipulation of pattern formation in self-organizing reaction-diffusion processes by appropriate control stimuli become increasingly important both in chemical engineering and cellular biochemistry. In a model study, we demonstrate here exemplarily the application of an efficient nonlinear model predictive control (NMPC) algorithm to real-time optimal feedback control of pattern formation in a bacterial chemotaxis system modeled by nonlinear partial differential equations. The corresponding drift-diffusion model type is representative for many (bio)chemical systems involving nonlinear reaction dynamics and nonlinear diffusion. We show how the computed optimal feedback control strategy exploits the system inherent physical property of wave propagation to achieve desired control aims. We discuss various applications of our approach to optimal control of spatiotemporal dynamics.

  1. Effect of process parameters on properties of Al-Si alloys cast by Rapid Slurry Formation (RSF) technique

    NASA Astrophysics Data System (ADS)

    Ratke, L.; Sharma, A.; Kohli, D.

    2012-01-01

    Rapid slurry formation is a semi-solid metal forming technique, which is based on a so-called solid enthalpy exchange material (EEM). It is a fascinating technology offering the opportunity to manufacture net-shaped metal components of complex geometry in a single forming operation. At the same time, high mechanical properties can be achieved due to the unique microstructure and flow behaviour. The major process parameters used in the RSF process are rotation speed of the EEM, melt superheat, amount of EEM added (determining fs), and holding time. The process parameters can be well controlled with clear effects on the microstructure. There is a lack of theoretical modelling of the morphological evolution in these two-phase slurries.

  2. Formation of ultrasharp vertically aligned Cu-Si nanocones by a DC plasma process.

    PubMed

    Klein, K L; Melechko, A V; Fowlkes, J D; Rack, P D; Hensley, D K; Meyer, H M; Allard, L F; McKnight, T E; Simpson, M L

    2006-03-16

    We report an effective method for the production of ultrasharp vertically oriented silicon nanocones with tip radii as small as 5 nm. These silicon nanostructures were shaped by a high-temperature acetylene and ammonia dc plasma reactive ion etch (RIE) process. Thin-film copper deposited onto Si substrates forms a copper silicide (Cu3Si) during plasma processing, which subsequently acts as a seed material masking the single-crystal cones while the exposed silicon areas are reactive ion etched. In this process, the cone angle is sharpened continually as the structure becomes taller. Furthermore, by lithographically defining the seed material as well as employing an etch barrier material such as titanium, the cone location and substrate topography can be controlled effectively.

  3. Study on the sintering and contact formation process of silver front side metallization pastes for crystalline silicon solar cells

    NASA Astrophysics Data System (ADS)

    Qin, Jun; Zhang, Weijun; Bai, Shuxin; Liu, Zhuofeng

    2016-07-01

    In the paper, sintering process and contact formation process of PTO glass containing pastes were studied by interrupting the firings at different temperatures. Microstructures of contact fingers fabricated using pastes with PTO glass by interrupted firings were obtained by FIB/SEM technology and the sintering process of pastes was studied. The sintering process of pastes can be divided into three stages, the initial stage, intermediate stage and final stage, respectively. Only during the initial stage and intermediate stage of sintering, Ag-containing glass-phase is able to flow downward to the interface of Ag/Si through the continuous pore channels between Ag particles due to the great densification of Ag in the final stage of sintering. The great disharmony between the flow process of glass-phase and Ag densification would cause much glass trapped in densified Ag and thereby non-uniform etching of Si wafers. Contact formation process of pastes was studied by observing the Ag contact and Si emitter interface. Ag precipitates can be observed in the interfacial glass-phase at low firing temperature. Ag crystallites embedded in Si emitter appear at relative high temperature, along with the decreased number of Ag precipitates located in the interfacial glass-phase. Lower viscosity and higher ion diffusion velocities of interfacial glass-phase will make Ag crystallites appear at lower temperature. The increased interfacial glass layer thickness and abnormal growth of Ag crystallites, together with the decreased number of Ag precipitates cause the increase of contact resistance with the increase of sintering temperature.

  4. Ultrafast formation of air-processable and high-quality polymer films on an aqueous substrate

    NASA Astrophysics Data System (ADS)

    Noh, Jonghyeon; Jeong, Seonju; Lee, Jung-Yong

    2016-08-01

    Polymer solar cells are attracting attention as next-generation energy sources. Scalable deposition techniques of high-quality organic films should be guaranteed to realize highly efficient polymer solar cells in large areas for commercial viability. Herein, we introduce an ultrafast, scalable, and versatile process for forming high-quality organic films on an aqueous substrate by utilizing the spontaneous spreading phenomenon. This approach provides easy control over the thickness of the films by tuning the spreading conditions, and the films can be transferred to a variety of secondary substrates. Moreover, the controlled Marangoni flow and ultrafast removal of solvent during the process cause the films to have a uniform, high-quality nanomorphology with finely separated phase domains. Polymer solar cells were fabricated from a mixture of polymer and fullerene derivatives on an aqueous substrate by using the proposed technique, and the device exhibited an excellent power conversion efficiency of 8.44 %. Furthermore, a roll-to-roll production system was proposed as an air-processable and scalable commercial process for fabricating organic devices.

  5. Cavity formation and surface modeling of laser milling process under a thin-flowing water layer

    NASA Astrophysics Data System (ADS)

    Tangwarodomnukun, Viboon

    2016-11-01

    Laser milling process normally involves a number of laser scans over a workpiece to selectively remove the material and then to form cavities with shape and dimensions required. However, this process adversely causes a heat accumulation in work material, which can in turn damage the laser-milled area and vicinity in terms of recast deposition and change of material properties. Laser milling process performing in a thin-flowing water layer is a promising method that can overcome such damage. With the use of this technique, water can flush away the cut debris and at the same time cool the workpiece during the ablation. To understand the potential of this technique for milling application, the effects of process parameters on cavity dimensions and surface roughness were experimentally examined in this study. Titanium sheet was used as a workpiece to be milled by a nanosecond pulse laser under different water flow velocities. A smooth and uniform cut feature can be obtained when the metal was ablated under the high laser pulse frequency and high water flow velocity. Furthermore, a surface model based on the energy balance was developed in this study to predict the cavity profile and surface roughness. By comparing to the experiments, the predicted profiles had a good agreement with the measured ones.

  6. Ultrafast formation of air-processable and high-quality polymer films on an aqueous substrate

    PubMed Central

    Noh, Jonghyeon; Jeong, Seonju; Lee, Jung-Yong

    2016-01-01

    Polymer solar cells are attracting attention as next-generation energy sources. Scalable deposition techniques of high-quality organic films should be guaranteed to realize highly efficient polymer solar cells in large areas for commercial viability. Herein, we introduce an ultrafast, scalable, and versatile process for forming high-quality organic films on an aqueous substrate by utilizing the spontaneous spreading phenomenon. This approach provides easy control over the thickness of the films by tuning the spreading conditions, and the films can be transferred to a variety of secondary substrates. Moreover, the controlled Marangoni flow and ultrafast removal of solvent during the process cause the films to have a uniform, high-quality nanomorphology with finely separated phase domains. Polymer solar cells were fabricated from a mixture of polymer and fullerene derivatives on an aqueous substrate by using the proposed technique, and the device exhibited an excellent power conversion efficiency of 8.44 %. Furthermore, a roll-to-roll production system was proposed as an air-processable and scalable commercial process for fabricating organic devices. PMID:27507624

  7. Integrating Professional Development Content and Formative Assessment with the Coaching Process: The Texas School Ready Model

    ERIC Educational Resources Information Center

    Crawford, April; Zucker, Tricia; Van Horne, Bethanie; Landry, Susan

    2017-01-01

    Instructional coaching is becoming common in early childhood programs to provide individualized, job-embedded professional development. Yet relatively few studies have tried to "unpack" the coaching process and delineate the specific features of coaching that contribute to teacher change. In this article, we describe an evidence-based…

  8. Laboratory studies on formation and minimisation of polychlorinated dibenzodioxins and -furans (PCDD/F) in secondary aluminium process.

    PubMed

    Lenoir, Dieter; Klobasa, Oliver; Pandelova, Marchela; Henkelmann, Bernhard; Schramm, Karl-Werner

    2012-05-01

    The objectives of this work were to study the formation mechanisms of polychlorinated dibenzo-p-dioxins/polychlorinated dibenzofurans (PCDD/F) in thermal aluminium recycling processes by use of laboratory experiments. The pattern of isomers of PCDD/F indicates that de novo synthesis is important in aluminium smeltery. The mechanisms of PCDD/F formation in aluminium smelting are similar to that of various incineration processes of waste material. The results of bioanalysis (EROD-test) confirms the existence of de novo synthesis of PCDD/F, but points out to the existence to some additional, toxic compounds of unknown structure. To reduce the amount of PCDD/F the input of carbon at the metal should be reduced; in addition the metal smeltery plants should be cleaned from fly ash particles. It is suggested to use good primary methods in the technical plants like constant feeding of the metal into the oven will minimise PCDD/F concentration. The biological EROD-bioassay is a good tool to estimate PCDD/F-TEQ values also for this technical process simulated in the laboratory.

  9. Microstructure formation mechanism and properties of AZ61 alloy processed by melt treatment with vibrating cooling slope and semisolid rolling

    NASA Astrophysics Data System (ADS)

    Zhao, Zhan Yong; Guan, Ren Guo; Wang, Xiang; Li, Yang; Dong, Lei; Lee, Chong Soo; Liu, Chun Ming

    2013-09-01

    A melt treatment with a vibrating cooling slope and a semisolid rolling process to produce an AZ61 alloy strip was proposed. The microstructure formation mechanism and the properties of the AZ61 alloy produced by the proposed process were investigated. Due to the high cooling rate and stirring action caused by the vibration cooling slope, the nucleation rate was greatly improved, which caused the formation of fine spherical or rosette primary grains. During the rolling process, the solid fraction increased from the entrance to the exit of the roll gap, and under the shearing action of the roller, the distribution of solute in the melt was homogenous, and the primary grains grew further. When the casting temperature was 680 °C, a strip with a cross section of 4 mm×160 mm was produced and a homogeneous microstructure was obtained. The ultimate tensile strength of the AZ61 alloy strip produced by the proposed method reached 242 MPa, and the corresponding elongation to failure was 4%, which were better than those achieved in previous similar studies.

  10. Use of Modeling for Prevention of Solids Formation During Canyon Processing of Legacy Nuclear Materials at the Savannah River Site

    SciTech Connect

    Rhodes, W. D.; Crooks III, W. J.; Christian, J. D.

    2002-02-26

    The Savannah River Site (SRS) Environmental Management (EM) nuclear material stabilization program includes the dissolution and processing of legacy materials from various DOE sites. The SRS canyon facilities were designed to dissolve and process spent nuclear fuel and targets. As the processing of typical materials is completed, unusual and exotic nuclear materials are being targeted for stabilization. These unusual materials are often difficult to dissolve using historical flowsheet conditions and require more aggressive dissolver solutions. Solids must be prevented in the dissolver to avoid expensive delays associated with the build-up of insoluble material in downstream process equipment. Moreover, it is vital to prevent precipitation of all solids, especially plutonium-bearing solids, since their presence in dissolver solutions raises criticality safety issues. To prevent precipitation of undesirable solids in aqueous process solutions, the accuracy of computer models to predict precipitate formation requires incorporation of plant specific fundamental data. These data are incorporated into a previously developed thermodynamic computer program that applies the Pitzer correlation to derive activity coefficient parameters. This improved predictive model will reduce unwanted precipitation in process solutions at DOE sites working with EM nuclear materials in aqueous solutions.

  11. Processes influencing formation of low-salinity high-biomass lenses near the edge of the Ross Ice Shelf

    NASA Astrophysics Data System (ADS)

    Li, Yizhen; McGillicuddy, Dennis J.; Dinniman, Michael S.; Klinck, John M.

    2017-02-01

    Both remotely sensed and in situ observations in austral summer of early 2012 in the Ross Sea suggest the presence of cold, low-salinity, and high-biomass eddies along the edge of the Ross Ice Shelf (RIS). Satellite measurements include sea surface temperature and ocean color, and shipboard data sets include hydrographic profiles, towed instrumentation, and underway acoustic Doppler current profilers. Idealized model simulations are utilized to examine the processes responsible for ice shelf eddy formation. 3-D model simulations produce similar cold and fresh eddies, although the simulated vertical lenses are quantitatively thinner than observed. Model sensitivity tests show that both basal melting underneath the ice shelf and irregularity of the ice shelf edge facilitate generation of cold and fresh eddies. 2-D model simulations further suggest that both basal melting and downwelling-favorable winds play crucial roles in forming a thick layer of low-salinity water observed along the edge of the RIS. These properties may have been entrained into the observed eddies, whereas that entrainment process was not captured in the specific eddy formation events studied in our 3-D model-which may explain the discrepancy between the simulated and observed eddies, at least in part. Additional sensitivity experiments imply that uncertainties associated with background stratification and wind stress may also explain why the model underestimates the thickness of the low-salinity lens in the eddy interiors. Our study highlights the importance of incorporating accurate wind forcing, basal melting, and ice shelf irregularity for simulating eddy formation near the RIS edge. The processes responsible for generating the high phytoplankton biomass inside these eddies remain to be elucidated.

  12. On Porosity Formation in Metal Matrix Composites Made with Dual-Scale Fiber Reinforcements Using Pressure Infiltration Process

    NASA Astrophysics Data System (ADS)

    Etemadi, Reihaneh; Pillai, Krishna M.; Rohatgi, Pradeep K.; Hamidi, Sajad Ahmad

    2015-05-01

    This is the first such study on porosity formation phenomena observed in dual-scale fiber preforms during the synthesis of metal matrix composites (MMCs) using the gas pressure infiltration process. In this paper, different mechanisms of porosity formation during pressure infiltration of Al-Si alloys into Nextel™ 3D-woven ceramic fabric reinforcements (a dual-porosity or dual-scale porous medium) are studied. The effect of processing conditions on porosity content of the ceramic fabric infiltrated by the alloys through the gas PIP (PIP stands for "Pressure Infiltration Process" in which liquid metal is injected under pressure into a mold packed with reinforcing fibers.) is investigated. Relative density (RD), defined as the ratio of the actual MMC density and the density obtained at ideal 100 pct saturation of the preform, was used to quantify the overall porosity. Increasing the infiltration temperature led to an increase in RD due to reduced viscosity of liquid metal and enhanced wettability leading to improved feedability of the liquid metal. Similarly, increasing the infiltration pressure led to enhanced penetration of fiber tows and resulted in higher RD and reduced porosity. For the first time, the modified Capillary number ( Ca*), which is found to predict formation of porosity in polymer matrix composites quite well, is employed to study porosity in MMCs made using PIP. It is observed that in the high Ca* regime which is common in PIP, the overall porosity shows a strong downward trend with increasing Ca*. In addition, the effect of matrix shrinkage on porosity content of the samples is studied through using a zero-shrinkage Al-Si alloy as the matrix; usage of this alloy as the matrix led to a reduction in porosity content.

  13. Inferring ice formation processes from global-scale black carbon profiles observed in the remote atmosphere and model simulations

    NASA Astrophysics Data System (ADS)

    Fan, S.-M.; Schwarz, J. P.; Liu, J.; Fahey, D. W.; Ginoux, P.; Horowitz, L. W.; Levy, H., II; Ming, Y.; Spackman, J. R.

    2012-12-01

    Black carbon (BC) aerosol absorbs solar radiation and can act as cloud condensation nucleus and ice formation nucleus. The current generation of climate models have difficulty in accurately predicting global-scale BC concentrations. Previously, an ensemble of such models was compared to measurements, revealing model biases in the tropical troposphere and in the polar troposphere. Here global aerosol distributions are simulated using different parameterizations of wet removal, and model results are compared to BC profiles observed in the remote atmosphere to explore the possible sources of these biases. The model-data comparison suggests a slow removal of BC aerosol during transport to the Arctic in winter and spring, because ice crystal growth causes evaporation of liquid cloud via the Bergeron process and, hence, release of BC aerosol back to ambient air. By contrast, more efficient model wet removal is needed in the cold upper troposphere over the tropical Pacific. Parcel model simulations with detailed droplet and ice nucleation and growth processes suggest that ice formation in this region may be suppressed due to a lack of ice nuclei (mainly insoluble dust particles) in the remote atmosphere, allowing liquid and mixed-phase clouds to persist under freezing temperatures, and forming liquid precipitation capable of removing aerosol incorporated in cloud water. Falling ice crystals can scavenge droplets in lower clouds, which also results in efficient removal of cloud condensation nuclei. The combination of models with global-scale BC measurements in this study has provided new, latitude-dependent information on ice formation processes in the atmosphere, and highlights the importance of a consistent treatment of aerosol and moist physics in climate models.

  14. Ozone process insights from field experiments - Part III: extent of reaction and ozone formation

    NASA Astrophysics Data System (ADS)

    Blanchard, Charles L.

    The analysis of ambient data offers a means of developing a qualitative understanding of the sensitivity of ozone formation at specific times and places to changes in VOC and NO x concentrations. The Integrated Empirical Rate (IER) model (Johnson, 1984, Proceedings of the Eighth International Clean Air Conference, Melbourne, Australia, pp. 715-731) and two revisions known as the Smog Production (SP) algorithm (Blanchard et al., 1999, Atmospheric Environment 33, 369-381; Chang et al., 1997, Atmospheric Environment 31, 2787-2794) are reviewed. Applied to ambient data, the algorithm requires measurements of ozone, NO, and either NO x or NO y and computes a quantity known as the extent of reaction. The extent of reaction is shown to be related to photochemical age and serves as an indicator of the sensitivity of instantaneous ozone production to changes in VOC or NO x concentrations. Extent of reaction alone is insufficient as an indicator of the sensitivity of ozone concentration to a complex upwind history of emission changes. Consideration of daily, hourly, and spatial patterns of extent of reaction is needed to interpret applications of the SP algorithm.

  15. Formation of low molecular weight oligomers from chitin and chitosan stimulated by plasma-assisted processes.

    PubMed

    Vasilieva, T; Sigarev, A; Kosyakov, D; Ul'yanovskii, N; Anikeenko, E; Chuhchin, D; Ladesov, A; Hein, Aung Myat; Miasnikov, V

    2017-05-01

    The controlled degradation of solid powders of chitin and chitosan stimulated by electron-beam plasma (EBP) was experimentally studied. Crab shell chitin and chitosan were used as original substances. The non-equilibrium low temperature EBP was generated by injecting an electron beam into a gaseous medium. Chitooligosaccharides with Mw=800-2000Da and polydispersion 1.5-2.5 were formed due to the EBP-treatment of chitin and chitosan. The β-1,4 glycosidic bounds in original polymers degrade under the action of active oxygen species produced in the EBP. Low molecular weight products of chitosan inhibited the growth of various yeast-like and filamentous fungi at minimum inhibitory concentration 500mcg/ml. By optimizing the treatment conditions and using special techniques of reaction volume formation the 95% yield of chitooligosaccharides was obtained after 2min whereas the conventional chemical hydrolysis usually takes several days. The EBP-stimulated hydrolysis is promising for effective polysaccharides degradation and can be competitive with traditional technologies.

  16. Conceptual model for transport processes in the Culebra Dolomite Member, Rustler Formation

    SciTech Connect

    Holt, R.M.

    1997-08-01

    The Culebra Dolomite Member of the Rustler Formation represents a possible pathway for contaminants from the Waste Isolation Pilot Plant underground repository to the accessible environment. The geologic character of the Culebra is consistent with a double-porosity, multiple-rate model for transport in which the medium is conceptualized as consisting of advective porosity, where solutes are carried by the groundwater flow, and fracture-bounded zones of diffusive porosity, where solutes move through slow advection or diffusion. As the advective travel length or travel time increases, the nature of transport within a double-porosity medium changes. This behavior is important for chemical sorption, because the specific surface area per unit mass of the diffusive porosity is much greater than in the advective porosity. Culebra transport experiments conducted at two different length scales show behavior consistent with a multiple-rate, double-porosity conceptual model for Culebra transport. Tracer tests conducted on intact core samples from the Culebra show no evidence of significant diffusion, suggesting that at the core scale the Culebra can be modeled as a single-porosity medium where only the advective porosity participates in transport. Field tracer tests conducted in the Culebra show strong double-porosity behavior that is best explained using a multiple-rate model.

  17. Sintering Behavior and Microstructure Formation of Titanium Aluminide Alloys Processed by Metal Injection Molding

    NASA Astrophysics Data System (ADS)

    Soyama, Juliano; Oehring, Michael; Ebel, Thomas; Kainer, Karl Ulrich; Pyczak, Florian

    2017-01-01

    The sintering behavior of metal injection molded titanium aluminide alloys, their microstructure formation and resulting mechanical properties were investigated. As reference material, the alloy Ti-45Al-5Nb-0.2B-0.2C at.% (TNB-V5) was selected. Additionally, two other variations with Mo and Mo + Si additions were prepared: Ti-45Al-3Nb-1Mo-0.2B-0.2C at.% and Ti-45Al-3Nb-1Mo-1Si-0.2B-0.2C at.%. The results indicate that the optimum sintering temperature was slightly above the solidus line. With proper sintering parameters, very low porosities (<0.5%) and fine microstructures with a colony size <85 µm could be achieved. Considering the sintering temperatures applied, the phase transformations upon cooling could be described as L + β → β → α + β → α → α + γ → α2 + γ, which was in agreement with the microstructures observed. The effects of Mo and Si were opposite regarding the sintering behavior. Mo addition led to an increase in the optimum sintering temperature, whereas Si caused a significant decrease.

  18. Understanding the Star Formation Process in the Filamentary Dark Cloud GF 9: Near-Infrared Observations

    NASA Technical Reports Server (NTRS)

    Ciardi, David R.; Woodward, Charles E.; Clemens, Dan P.; Harker, David E.; Rudy, Richard J.

    1998-01-01

    We have performed a near-infrared JHK survey of a dense core and a diffuse filament region within the filamentary dark cloud GF 9 (LDN 1082). The core region is associated with the IRAS point source PSC 20503+6006 and is suspected of being a site of star formation. The diffuse filament region has no associated IRAS point sources and is likely quiescent. We find that neither the core nor the filament region appears to contain a Class I or Class II young stellar object. As traced by the dust extinction, the core and filament regions contain 26 and 22 solar mass, respectively, with an average H2 volume density for both regions of approximately 2500/cu cm. The core region contains a centrally condensed extinction maximum with a peak extinction of A(sub v) greater than or approximately equal to 10 mag that appears to be associated with the IRAS point source. The average H2 volume density of the extinction core is approximately 8000/cu cm. The dust within the filament, however, shows no sign of a central condensation and is consistent with a uniform-density cylindrical distribution.

  19. Raf-1 Activation Prevents Caspase 9 Processing Downstream of Apoptosome Formation

    PubMed Central

    Cagnol, Sébastien; Mansour, Anna; Van Obberghen-Schilling, Ellen; Chambard, Jean-Claude

    2011-01-01

    In many cell types, growth factor removal induces the release of cytochrome-c from mitochondria that leads to activation of caspase-9 in the apoptosome complex. Here, we show that sustained stimulation of the Raf-1/MAPK1,3 pathway prevents caspase-9 activation induced by serum depletion in CCL39/ΔRaf-1:ER fibroblasts. The protective effect mediated by Raf-1 is sensitive to MEK inhibition that is sufficient to induce caspase-9 cleavage in exponentially growing cells. Raf-1 activation does not inhibit the release of cytochrome-c from mitochondria while preventing caspase-9 activation. Gel filtration chromatography analysis of apoptosome formation in cells shows that Raf-1/MAPK1,3 activation does not interfere with APAF-1 oligomerization and recruitment of caspase 9. Raf-1-mediated caspase-9 inhibition is sensitive to emetine, indicating that the protective mechanism requires protein synthesis. However, the Raf/MAPK1,3 pathway does not regulate XIAP. Taken together, these results indicate that the Raf-1/MAPK1,3 pathway controls an apoptosis regulator that prevents caspase-9 activation in the apoptosome complex. PMID:21637382

  20. Complex igneous processes and the formation of the primitive lunar crustal rocks

    NASA Technical Reports Server (NTRS)

    Longhi, J.; Boudreau, A. E.

    1979-01-01

    Crystallization of a magma ocean with initial chondritic Ca/Al and REE ratios such as proposed by Taylor and Bence (TB, 1975), is capable of producing the suite of primitive crustal rocks if the magma ocean underwent locally extensive assimilation and mixing in its upper layers as preliminary steps in formation of an anorthositic crust. Lunar anorthosites were the earliest permanent crustal rocks to form the result of multiple cycles of suspension and assimilation of plagioclase in liquids fractionating olivine and pyroxene. There may be two series of Mg-rich cumulate rocks: one which developed as a result of the equilibration of anorthositic crust with the magma ocean; the other which formed in the later stages of the magma ocean during an epoch of magma mixing and ilmenite crystallization. This second series may be related to KREEP genesis. It is noted that crystallization of the magma ocean had two components: a low pressure component which produced a highly fractionated and heterogeneous crust growing downward and a high pressure component which filled in the ocean from the bottom up, mostly with olivine and low-Ca pyroxene.