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Sample records for core capping leads

  1. Devon island ice cap: core stratigraphy and paleoclimate.

    PubMed

    Koerner, R M

    1977-04-01

    Valuable paleoclimatic information can be gained by studying the distribution of melt layers in deep ice cores. A profile representing the percentage of ice in melt layers in a core drilled from the Devon Island ice cap plotted against both time and depth shows that the ice cap has experienced a period of very warm summers since 1925, following a period of colder summers between about 1600 and 1925. The earlier period was coldest between 1680 and 1730. There is a high correlation between the melt-layer ice percentage and the mass balance of the ice cap. The relation between them suggests that the ice cap mass balance was zero (accumulation equaled ablation) during the colder period but is negative in the present warmer one. There is no firm evidence of a present cooling trend in the summer conditions on the ice cap. A comparison with the melt-layer ice percentage in cores from the other major Canadian Arctic ice caps shows that the variation of summer conditions found for the Devon Island ice cap is representative for all the large ice caps for about 90 percent of the time. There is also a good correlation between melt-layer percentage and summer sea-ice conditions in the archipelago. This suggests that the search for the northwest passage was influenced by changing climate, with the 19th-century peak of the often tragic exploration coinciding with a period of very cold summers. PMID:17733504

  2. Devon island ice cap: core stratigraphy and paleoclimate.

    PubMed

    Koerner, R M

    1977-04-01

    Valuable paleoclimatic information can be gained by studying the distribution of melt layers in deep ice cores. A profile representing the percentage of ice in melt layers in a core drilled from the Devon Island ice cap plotted against both time and depth shows that the ice cap has experienced a period of very warm summers since 1925, following a period of colder summers between about 1600 and 1925. The earlier period was coldest between 1680 and 1730. There is a high correlation between the melt-layer ice percentage and the mass balance of the ice cap. The relation between them suggests that the ice cap mass balance was zero (accumulation equaled ablation) during the colder period but is negative in the present warmer one. There is no firm evidence of a present cooling trend in the summer conditions on the ice cap. A comparison with the melt-layer ice percentage in cores from the other major Canadian Arctic ice caps shows that the variation of summer conditions found for the Devon Island ice cap is representative for all the large ice caps for about 90 percent of the time. There is also a good correlation between melt-layer percentage and summer sea-ice conditions in the archipelago. This suggests that the search for the northwest passage was influenced by changing climate, with the 19th-century peak of the often tragic exploration coinciding with a period of very cold summers.

  3. Modeling the Arm II core in MicroCap IV

    SciTech Connect

    Dalton, A.C.

    1996-11-01

    This paper reports on how an electrical model for the core of the Arm II machine was created and how to use this model. We wanted to get a model for the electrical characteristics of the ARM II core, in order to simulate this machine and to assist in the design of a future machine. We wanted this model to be able to simulate saturation, variable loss, and reset. Using the Hodgdon model and the circuit analysis program MicroCap IV, this was accomplished. This paper is written in such a way as to allow someone not familiar with the project to understand it.

  4. Investigation of fibrous cap stresses on vulnerable plaques leading to heart attacks.

    PubMed

    Hsiao, Hao-Ming; Wu, Yi-Yu; Tsai, Bo-Chian; Chen, Yung-Chi; Cheng, Yu-Han

    2015-01-01

    Rupture-prone plaques in the coronary arteries, called ``vulnerable plaques'', are recognized as the key factor in acute myocardial infarction. Vulnerable plaques have a thin fibrous cap over a large fatty core and are highly susceptible to rupture. In general, this type of plaque rupture is mainly associated with stress concentrated on the fibrous cap. Fibrous cap stresses are counted among the most important factors in the plaque rupture process and must be taken into consideration when assessing the plaque vulnerability leading to heart attacks. The objective of this paper was to investigate the effects of nitinol stent deployment on the morphological changes of vulnerable plaques and then to propose a new stent design concept for effectively reducing fibrous cap stresses and the associated rupture risk. The deployment of a self-expanding nitinol stent was modeled, and the resulting stress distribution on the fibrous cap was investigated. The fibrous cap stresses were more uniformly distributed and the maximum stress was reduced by 13% when the crown number of the stent was increased. This study demonstrates an excellent approach to stent design that could effectively reduce the risk of a vulnerable plaque rupturing and causing a heart attack. PMID:26684564

  5. Resident CAPS on dense-core vesicles docks and primes vesicles for fusion

    PubMed Central

    Kabachinski, Greg; Kielar-Grevstad, D. Michelle; Zhang, Xingmin; James, Declan J.; Martin, Thomas F. J.

    2016-01-01

    The Ca2+-dependent exocytosis of dense-core vesicles in neuroendocrine cells requires a priming step during which SNARE protein complexes assemble. CAPS (aka CADPS) is one of several factors required for vesicle priming; however, the localization and dynamics of CAPS at sites of exocytosis in live neuroendocrine cells has not been determined. We imaged CAPS before, during, and after single-vesicle fusion events in PC12 cells by TIRF micro­scopy. In addition to being a resident on cytoplasmic dense-core vesicles, CAPS was present in clusters of approximately nine molecules near the plasma membrane that corresponded to docked/tethered vesicles. CAPS accompanied vesicles to the plasma membrane and was present at all vesicle exocytic events. The knockdown of CAPS by shRNA eliminated the VAMP-2–dependent docking and evoked exocytosis of fusion-competent vesicles. A CAPS(ΔC135) protein that does not localize to vesicles failed to rescue vesicle docking and evoked exocytosis in CAPS-depleted cells, showing that CAPS residence on vesicles is essential. Our results indicate that dense-core vesicles carry CAPS to sites of exocytosis, where CAPS promotes vesicle docking and fusion competence, probably by initiating SNARE complex assembly. PMID:26700319

  6. Imaging and analysis of microcalcifications and lipid/necrotic core calcification in fibrous cap atheroma.

    PubMed

    Maldonado, Natalia; Kelly-Arnold, Adreanne; Laudier, Damien; Weinbaum, Sheldon; Cardoso, Luis

    2015-06-01

    The presence of microcalcifications (µCalcs) >5 µm within the cap of human fibroatheroma has been shown to produce a 200-700% increase in peak circumferential stress, which can transform a stable plaque into a vulnerable one, whereas µCalcs < 5 µm do not appear to increase risk. We quantitatively examine the possibility to distinguish caps with µCalcs > 5 µm based on the gross morphological features of fibroatheromas, and the correlation between the size and distribution of µCalcs in the cap and the calcification in the lipid/necrotic core beneath it. Atherosclerotic lesions (N = 72) were imaged using HR-μCT at 2.1-μm resolution for detailed analysis of atheroma morphology and composition, and validated using non-decalcified histology. At 2.1-μm resolution one observes four different patterns of calcification within the lipid/necrotic core, and is able to elucidate the 3D spatial progression of the calcification process using these four patterns. Of the gross morphological features identified, only minimum cap thickness positively correlated with the existence of µCalcs > 5 µm in the cap. We also show that µCalcs in the cap accumulate in the vicinity of the lipid/necrotic core boundary with few on the lumen side of the cap. HR-μCT enables three-dimensional assessment of soft tissue composition, lipid content, calcification patterns within lipid/necrotic cores and analysis of the axial progression of calcification within individual atheroma. The distribution of µCalcs within the cap is highly non-uniform and decreases sharply as one proceeds from the lipid pool/necrotic core boundary to the lumen. PMID:25837377

  7. Earth's polar cap ionization patches lead to ion upflow

    NASA Astrophysics Data System (ADS)

    Zhang, Q. H.; Zong, Q.; Lockwood, M. M.; Liang, J.; Zhang, B.; Moen, J. I.; Zhang, S.; Zhang, Y.; Ruohoniemi, J. M.; Thomas, E. G.; Liu, R.; Dunlop, M. W.; Yang, H. G.; Hu, H.; Liu, Y.; Lester, M.

    2014-12-01

    The Earth constantly losses matter through ions escaping from the polar ionosphere. This makes the ionosphere as an important source of plasma for the magnetosphere and could modulate atmospheric isotope abundances on geological timescales, depending on what fraction of the upflowing ions subsequently return to the ionosphere and what fraction are ejected into interplanetary space. It has been proposed that the magnetosphere is dynamically modulated by the presence of the ionospheric ions, particularly heavy ions O+, during magnetic substorms and storms. The origin and formation mechanism of ionospheric ion upflow is, however, poorly understood, particularly under disturbed space weather conditions. We report simultaneous direct observations of ion upflow and a patch of ionization at the center of the polar cap region during a geomagnetic storm. Our observations indicate enhanced fluxes of upwelling O+ ions originate from the patch and were accelerated by the enhanced ambipolar electric field. This enhancement is caused by soft electron precipitations. Polar cap patches therefore provide an important source of upwelling ions for accelerations mechanisms at greater altitudes which can eject the ions. These observations give new insight into the processes of ionosphere-magnetosphere coupling and the potential loss of terrestrial water dissociation products into space which, although extremely slow in the case of Earth, may be significant for other planets and moons.

  8. Air-Cooled Turbine Blades with Tip Cap For Improved Leading-Edge Cooling

    NASA Technical Reports Server (NTRS)

    Calvert, Howard F.; Meyer, Andre J., Jr.; Morgan, William C.

    1959-01-01

    An investigation was conducted in a modified turbojet engine to determine the cooling characteristics of the semistrut corrugated air- cooled turbine blade and to compare and evaluate a leading-edge tip cap as a means for improving the leading-edge cooling characteristics of cooled turbine blades. Temperature data were obtained from uncapped air-cooled blades (blade A), cooled blades with the leading-edge tip area capped (blade B), and blades with slanted corrugations in addition to leading-edge tip caps (blade C). All data are for rated engine speed and turbine-inlet temperature (1660 F). A comparison of temperature data from blades A and B showed a leading-edge temperature reduction of about 130 F that could be attributed to the use of tip caps. Even better leading-edge cooling was obtained with blade C. Blade C also operated with the smallest chordwise temperature gradients of the blades tested, but tip-capped blade B operated with the lowest average chordwise temperature. According to a correlation of the experimental data, all three blade types 0 could operate satisfactorily with a turbine-inlet temperature of 2000 F and a coolant flow of 3 percent of engine mass flow or less, with an average chordwise temperature limit of 1400 F. Within the range of coolant flows investigated, however, only blade C could maintain a leading-edge temperature of 1400 F for a turbine-inlet temperature of 2000 F.

  9. Space Shuttle Orbiter nose cap and wing leading edge certification test program

    NASA Technical Reports Server (NTRS)

    Suppanz, M. J.; Grimaud, J. E.

    1980-01-01

    A reinforced carbon-carbon thermal protection system is used on the space shuttle orbiter vehicle's nose cap and wing leading edge regions where temperatures reach 1538 C (2800 F). To verify the analyses used to certify reinforced carbon-carbon for the first flight and operational missions, a multi-environment incremental test program was developed and implemented through the combined efforts of Rockwell International and the National Aeronautics and Space Administration. Three separate facilities at the Johnson Space Center were used to subject full-scale nose cap and wing leading edge test articles to simulated critical launch, on-orbit, and atmospheric entry environments.

  10. CAPS-1 promotes fusion competence of stationary dense-core vesicles in presynaptic terminals of mammalian neurons

    PubMed Central

    Farina, Margherita; van de Bospoort, Rhea; He, Enqi; Persoon, Claudia M; van Weering, Jan RT; Broeke, Jurjen H; Verhage, Matthijs; Toonen, Ruud F

    2015-01-01

    Neuropeptides released from dense-core vesicles (DCVs) modulate neuronal activity, but the molecules driving DCV secretion in mammalian neurons are largely unknown. We studied the role of calcium-activator protein for secretion (CAPS) proteins in neuronal DCV secretion at single vesicle resolution. Endogenous CAPS-1 co-localized with synaptic markers but was not enriched at every synapse. Deletion of CAPS-1 and CAPS-2 did not affect DCV biogenesis, loading, transport or docking, but DCV secretion was reduced by 70% in CAPS-1/CAPS-2 double null mutant (DKO) neurons and remaining fusion events required prolonged stimulation. CAPS deletion specifically reduced secretion of stationary DCVs. CAPS-1-EYFP expression in DKO neurons restored DCV secretion, but CAPS-1-EYFP and DCVs rarely traveled together. Synaptic localization of CAPS-1-EYFP in DKO neurons was calcium dependent and DCV fusion probability correlated with synaptic CAPS-1-EYFP expression. These data indicate that CAPS-1 promotes fusion competence of immobile (tethered) DCVs in presynaptic terminals and that CAPS-1 localization to DCVs is probably not essential for this role. DOI: http://dx.doi.org/10.7554/eLife.05438.001 PMID:25719439

  11. Tennis core strings of polyamide-6 modified by surface-capped nano-silica

    NASA Astrophysics Data System (ADS)

    Liu, Juan; Yi, Hongling; Lin, Heng; Zheng, Baicun

    2013-01-01

    A new method that modified silica nanoparticles were infused into PA6 is to produce tennis core string through a melt-extrusion process. The idea was to produce a highly strong and elastic tennis core string of PA6, utilizing the interactions between modified silica and polymer. The effects of surface-capped nano-silica on the strength and elongation of tennis core string were studied. It has been observed that with the infusion of silica nanoparticles modified by γ-glycidoxypropyltrimethoxysilane (GPS), the stress at breaking and E-modulus of tennis core string is enhanced by 46.24% and 15.17% comparing with neat PA6 with changeless elongation at breaking at a critical concentration. The source of this improvement has been traced to the produced strong covalent bond and hydrogen bond between epoxy groups and-COOH and-NH2 in polyamide. Besides, compared with kinds of others strings of previous research results, tennis core string added nano-silica modified by γ-glycidoxypropyltrimethoxysilane (GPS) has a strength at breaking at 352.43 MPa exceeding the natural gut string, the polyvinylidene fluoride (PVDF), Monofil string and integrated nylon string by 42.05%, 4.49% and 9.38%, respectively. Meanwhile, tennis core string of polyamide modified by surface-capped nanosilica (PGMNS) has a higher elastic ratio at 0.15 than the other four strings.

  12. Lead, zinc, and strontium in limestone cap rock from Tatum salt dome, Mississippi

    SciTech Connect

    Saunders, J.A.

    1988-09-01

    Limestone cap rock at Tatum salt dome, Mississippi, contains disseminated pyrite, sphalerite, and galena, and disseminated to massive amounts of strontianite (SrCO/sub 3/) and celestite (SrSO/sub 4/). Sulfide minerals are locally present in bitumen-rich areas of the upper, massive portion of the limestone cap rock, whereas strontium minerals are disseminated throughout this zone. However, sulfide and strontium minerals are most abundant in the lower banded portion of the limestone cap rock, which consists of alternating subhorizontal light and dark-colored bands. The dark bands are composed of calcite of variable grain size, sulfides, quartz, dolomite, albite, and up to 1% bitumen that apparently formed by the biodegradation of crude oil. Lighter bands are composed of variable amounts of coarsely crystalline, euhedral calcite, strontianite, and celestite resulting in strontium (Sr) contents of up to 30% locally. Banded limestone cap rock at Tatum dome formed at the top of the actively dissolving anhydrite zone by a combination of sulfate reduction and oxidation of liquid hydrocarbons by bacteria to cause the precipitation of calcite and sulfide minerals and the accumulation of insoluble residue from the anhydrite (quartz, albite, dolomite). Lead and zinc in the sulfide minerals could have been derived from the dissolving anhydrite, but the abundance of Sr minerals present requires an external source. Present-day oil field brines in central Mississippi contain up to 3000 ppm Sr, and basin brines of similar composition apparently contributed Sr to the cap-rock environment during formation.

  13. Leading Change: Transitioning to the Common Core

    ERIC Educational Resources Information Center

    Brandt, Brian

    2012-01-01

    For many school districts in the United States, making the transition to the Common Core State Standards (CCSS) is proving to be a challenge at a time when they are already facing many obstacles, not the least of which is dwindling financial resources. A change of this magnitude cannot be made haphazardly; to be successful in its goal of helping…

  14. Dissolved Chemical Ions in an Ice Core of Grigoriev Ice Cap, Kyrgyz Tien Shan

    NASA Astrophysics Data System (ADS)

    SHUN, A.; Takeuchi, N.; Sera, S.; Fujita, K.; Okamoto, S.; Naoki, K.; Aizen, V. B.

    2012-12-01

    Snow and ice of glaciers contain various chemical ions supplied through the atmosphere and preserve them for a long period of time. Thus, analysis of soluble ions in glaciers is important to reveal material circulation and climate change in the cryosphere. Many glaciers are distributed over the mountains of the Central Asia. Chemical analysis of ice cores recovered from there play an important role to understand the atmosphere and material circulation peculiar to the Eurasian Continent. In this study, we analyzed the concentration of major ions in the ice core drilled on Grigoriev Ice Cap, Kyrgys Tien Shan, located in the northwestern part of Central Asia. We aim to understand material circulation in this area based on the chemical records. Then, we have attempted to reconstruct the environmental change of Central Asia, combining the chronology, hydrogen and oxygen stable isotope ratio, and density of dust in the ice core analyzed by prior researches. In this study, we used 2,176 samples of a snow pit and ice core from the surface to bed (86.87 m total length) on the top of Grigoriev Ice Cap (4,660 m high), Kyrgys Tien Shan in September, 2007. Samples were cut every 1-5 cm and scraped thinly, and transported frozen to Chiba University, Japan. After that, we dispensed those for various experiments, and analyzed the concentration of major ions using ion chromatography. By the way, it is estimated that the date of the bottom of this ice core is approximately 12,000 years ago by prior researches. The concentration of major ions dissolved in the ice core of Grigoriev Ice Cap revealed that Ca is the most dominant species in the measured ions and it accounted for more than 50 % (Eq ratio) of the mean of the entire core. This suggests that CaCO3 included in mineral dust derived from deserts around Tien Shan strongly influence the chemical composition of the Ice Cap. In addition, this composition is similar to those of Urumqi No.1 Glacier (Tien Shan), Mustagh Ata Glacier

  15. Studies on the chemical synthesis and characterization of lead oxide nanoparticles with different organic capping agents

    SciTech Connect

    Arulmozhi, K. T.; Mythili, N.

    2013-12-15

    Lead oxide (PbO) nanoparticles were chemically synthesized using Lead (II) acetate as precursor. The effects of organic capping agents such as Oleic acid, Ethylene Diamine Tetra Acetic acid (EDTA) and Cetryl Tri Methyl Butoxide (CTAB) on the size and morphology of the nanoparticles were studied. Characterization techniques such as X-ray diffraction (XRD), Fourier Transform-Infrared spectroscopy (FT-IR), Photoluminescence (PL) Field Emission Scanning Electron Microscopy (FE-SEM), Energy Dispersive Spectroscopy (EDS) and Transmission Electron Microscopy (TEM) were used to analyse the prepared nanoparticles for their physical, structural and optical properties. The characterization studies reveal that the synthesized PbO nanoparticles had well defined crystalline structure and sizes in the range of 25 nm to 36 nm for capping agents used and 40 nm for pure PbO nanoparticles.

  16. The addition of red lead to flat plate and tubular valve regulated miners cap lamp lead-acid batteries

    NASA Astrophysics Data System (ADS)

    Ferg, E. E.; Loyson, P.; Poorun, A.

    The study looked at the use of red lead in the manufacturing of valve regulated lead acid (VRLA) miners cap lamp (MCL) batteries that were made with either flat plate or tubular positive electrodes. A problem with using only grey oxide in the manufacture of thick flat plate or tubular electrodes is the poor conversion of the active material to the desired lead dioxide. The addition of red lead to the initial starting material improves the formation efficiency but is considerably more expensive thereby increasing the cost of manufacturing. The study showed that by carefully controlling the formation conditions in terms of the voltage and temperature of a battery, good capacity performance can be achieved for cells made with flat plate electrodes that contain up to 25% red lead. The small amount of red lead in the active cured material reduces the effect of electrode surface sulphate formation and allows the battery to achieve its rated capacity within the first few cycles. Batteries made with flat plate positive electrodes that contained more that 50% red lead showed good initial capacity but had poor structural active material bonding. The study showed that MCL batteries made with tubular positive electrodes that contained less than 75% red lead resulted in a poorly formed electrode with limited capacity utilization. Pickling and soaking times of the tubular electrodes should be kept at a minimum thereby allowing higher active material utilization during subsequent capacity cycling. The study further showed that it is beneficial to use higher formation rates in order to reduce manufacturing time and to improve the active material characteristics.

  17. The Earth's missing lead may not be in the core.

    PubMed

    Lagos, M; Ballhaus, C; Münker, C; Wohlgemuth-Ueberwasser, C; Berndt, J; Kuzmin, Dmitry V

    2008-11-01

    Relative to the CI chondrite class of meteorites (widely thought to be the 'building blocks' of the terrestrial planets), the Earth is depleted in volatile elements. For most elements this depletion is thought to be a solar nebular signature, as chondrites show depletions qualitatively similar to that of the Earth. On the other hand, as lead is a volatile element, some Pb may also have been lost after accretion. The unique (206)Pb/(204)Pb and (207)Pb/(204)Pb ratios of the Earth's mantle suggest that some lead was lost about 50 to 130 Myr after Solar System formation. This has commonly been explained by lead lost via the segregation of a sulphide melt to the Earth's core, which assumes that lead has an affinity towards sulphide. Some models, however, have reconciled the Earth's lead deficit with volatilization. Whichever model is preferred, the broad coincidence of U-Pb model ages with the age of the Moon suggests that lead loss may be related to the Moon-forming impact. Here we report partitioning experiments in metal-sulphide-silicate systems. We show that lead is neither siderophile nor chalcophile enough to explain the high U/Pb ratio of the Earth's mantle as being a result of lead pumping to the core. The Earth may have accreted from initially volatile-depleted material, some lead may have been lost to degassing following the Moon-forming giant impact, or a hidden reservoir exists in the deep mantle with lead isotope compositions complementary to upper-mantle values; it is unlikely though that the missing lead resides in the core.

  18. UNC-31/CAPS docks and primes dense core vesicles in C. elegans neurons.

    PubMed

    Lin, Xian-Guang; Ming, Min; Chen, Mao-Rong; Niu, Wei-Pin; Zhang, Yong-Deng; Liu, Bei; Jiu, Ya-Ming; Yu, Jun-Wei; Xu, Tao; Wu, Zheng-Xing

    2010-07-01

    UNC-31 or its mammalian homologue, Ca(2+)-dependent activator protein for secretion (CAPS), is indispensable for exocytosis of dense core vesicle (DCV) and synaptic vesicle (SV). From N- to the C-terminus, UNC-31 contains putative functional domains, including dynactin 1 binding domain (DBD), C2, PH, (M)UNC-13 homology domain (MHD) and DCV binding domain (DCVBD), the last four we examined in this study. We employed UNC-31 null mutant C. elegans worms to examine whether UNC-31 functions could be rescued by ectopic expression of full length UNC-31 vs each of these four domain-deleted mutants. Full length UNC-31 cDNA rescued the phenotypes of C. elegans null mutants in response to Ca(2+)-elevation in ALA neurons. Surprisingly, MHD deletion also rescued UNC-31 exocytotic function in part because the relatively high Ca(2+) level (pre-flash Ca(2+) was 450 nM) used in the capacitance study could bypass the MHD defect. Nonetheless, the three other domain-truncation cDNAs had almost no rescue on Ca(2+) evoked secretion. Importantly, this genetic null mutant rescue strategy enabled physiological studies at levels of whole organism to single cells, such as locomotion assay, pharmacological study of neurotransmission at neuromuscular junction, in vivo neuropeptide release measurement and analysis of vesicular docking. Our results suggest that each of these UNC-31 domains support distinct sequential molecular actions of UNC-31 in vesicular exocytosis, including steps in vesicle tethering and docking that bridge vesicle with plasma membrane, and subsequently priming vesicle by initiating the formation of soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) core complex. PMID:20515653

  19. Sedimentology of box cores from the Cap-Ferret Canyon area (Bay of Biscay)

    NASA Astrophysics Data System (ADS)

    Cremer, Michel; Weber, Olivier; Jouanneau, Jean-Marie

    1999-10-01

    Sedimentological and geochemical investigations of 45 box cores collected in various morphological settings of the Cap-Ferret Canyon (Bay of Biscay) are presented to document accurately present-day sedimentary processes on the eastern Atlantic continental slope. The magnitude and variations through time and space of the canyon's channelling or sinking effect on fine-grained particles behaviour in comparison with sediment flux across the continental margin was particularly considered and discussed: 1. All the parameters (grain-size, carbonate and water content, major and trace elements), measured both in surface sediment and downcore, demonstrate that the characteristics at the sediment interface vary with water depth and with the morphological setting. 2. Surface sediment is generally coarser-grained, more terrigenous and deposited at higher rate in the canyon than outside. The terrigenous particle supply must be preferentially directed and trapped within the canyon's depression due to present-day dynamic conditions. 3. The downcore gradients reflected in grain-size variations yield information on settling processes. The coarse-grained population has the characteristics of a winnowed sediment similar to those on the outer shelf, while the fine-grained population has grain-size spectra very similar to the present-day fine-grained suspensions. 4. The carbonate particles are partly derived from direct pelagic production (distinct grain-size distribution) and, like terrigenous grains, are partly reworked (similar downslope decrease in the coarse grained fraction). The relatively low CaCO 3 content observed in the canyon, and its downward increase up to values observed at shallower depths, may result from a channelling of terrigenous suspensions within the canyon. 5. At the present high sea-level stand, the canyon should become a trap for sediments without much gravity remobilisation, as indicated by a lack of sedimentary structures in box cores. However, a simple

  20. Snow algae in an ice core drilled on Grigoriev Ice cap in the Kyrgyz Tien Shen Mountains

    NASA Astrophysics Data System (ADS)

    Honda, M.; Takeuchi, N.; Sera, S.; Fujita, K.; Okamoto, S.; Naoki, K.; Aizen, V. B.

    2012-12-01

    Snow algae are photosynthetic microorganisms and are living on the surfase of glaciers. They grow on melting surface from spring to summer and their biomass and community structure are changed with physical and chemical conditions on glaciers. Ice cores drilled from glaciers also contain snow algae that grew in the past. Studying biomass and community structure of snow algae in ice cores could reveal the temporal variation in snow algae in the past, and also environmental conditions relating propagation of snow algae. In this study, we anlalyzed snow algae preserved in an ice core of Grigoriev Ice cap located in eastern Kyrgyzstan of the central Asia, and to describe their temporal variations for the last 200 years. The ice core drilling was carried out on September in 2007 on the Grigoriev Ice cap in the Kyrgyz Tien Shen Mountains. A 87 m long ice core from the surface to the bedrock was recovered at the top of the ice cap. The core was horizontally cut every 5 cm (total 1212 samples). The samples were melted and preserved as a 3% formalin solution. After the sample water was filtered through a hydrophilized PTFE membrane filter, observed by microscope. Snow algae in the sample water were counting. The algal biomass was represented by the cell number per unit water volume. Here, we showed the results between the surface to the 64 m in depth. We also analyzed the snow algal communities on the surface of the ice cap collected from five different sites from the top down to the terminus. Microscopy revealed that the ice core contained three taxa of filamentous cyanobacteria, an unicellular cyanobacterium, and two green algae. They were also found on the ice or snow surface of the i Ice cap. The quantitative analyses of the algae in the part of upper 64 m deep of the ice core samples revealed that the algal biomass varied significantly and showed many peaks. Furthermore, the biomass profile differed among the taxa. The filamentous cyanobacterium varied from 0.0 to 4

  1. VENUS-F: A fast lead critical core for benchmarking

    SciTech Connect

    Kochetkov, A.; Wagemans, J.; Vittiglio, G.

    2011-07-01

    The zero-power thermal neutron water-moderated facility VENUS at SCK-CEN has been extensively used for benchmarking in the past. In accordance with GEN-IV design tasks (fast reactor systems and accelerator driven systems), the VENUS facility was modified in 2007-2010 into the fast neutron facility VENUS-F with solid core components. This paper introduces the projects GUINEVERE and FREYA, which are being conducted at the VENUS-F facility, and it presents the measurement results obtained at the first critical core. Throughout the projects other fast lead benchmarks also will be investigated. The measurement results of the different configurations can all be used as fast neutron benchmarks. (authors)

  2. Investigating the effect of modifying the EEG cap lead configuration on the gradient artifact in simultaneous EEG-fMRI.

    PubMed

    Mullinger, Karen J; Chowdhury, Muhammad E H; Bowtell, Richard

    2014-01-01

    EEG data recorded during simultaneous fMRI are contaminated by large voltages generated by time-varying magnetic field gradients. Correction of the resulting gradient artifact (GA) generally involves low-pass filtering to attenuate the high-frequency voltage fluctuations of the GA, followed by subtraction of a GA template produced by averaging over repeats of the artifact waveforms. This average artifact subtraction (AAS) process relies on the EEG amplifier having a large enough dynamic range to characterize the artifact voltages and on invariance of the artifact waveform over repeated image acquisitions. Saturation of the amplifiers and changes in subject position can leave unwanted residual GA after AAS. Previous modeling work suggested that modifying the lead layout and the exit position of the cable bundle on the EEG cap could reduce the GA amplitude. Here, we used simulations and experiments to evaluate the effect of modifying the lead paths on the magnitude of the GA and on the residual artifact after AAS. The modeling work showed that for wire paths following great circles, the smallest overall GA occurs when the leads converge at electrode Cz. The performance of this new cap design was compared with a standard cap in experiments on a spherical agar phantom and human subjects. Using gradient pulses applied separately along the three Cartesian axes, we found that the GA due to the foot-head gradient was most significantly reduced relative to a standard cap for the phantom, whereas the anterior-posterior GA was most attenuated for human subjects. In addition, there was an overall 37% reduction in the RMS GA amplitude produced by a standard EPI sequence when comparing the two caps on the phantom. In contrast, the subjects showed an 11% increase in the average RMS of the GA. This work shows that the optimal design reduces the GA on a spherical phantom however; these gains are not translated to human subjects, probably due to the differences in geometry. PMID

  3. Disruption of a conserved CAP-D3 threonine alters condensin loading on mitotic chromosomes leading to chromosome hypercondensation.

    PubMed

    Bakhrebah, Muhammed; Zhang, Tao; Mann, Jeff R; Kalitsis, Paul; Hudson, Damien F

    2015-03-01

    The condensin complex plays a key role in organizing mitotic chromosomes. In vertebrates, there are two condensin complexes that have independent and cooperative roles in folding mitotic chromosomes. In this study, we dissect the role of a putative Cdk1 site on the condensin II subunit CAP-D3 in chicken DT40 cells. This conserved site has been shown to activate condensin II during prophase in human cells, and facilitate further phosphorylation by polo-like kinase I. We examined the functional significance of this phosphorylation mark by mutating the orthologous site of CAP-D3 (CAP-D3(T1403A)) in chicken DT40 cells. We show that this mutation is a gain of function mutant in chicken cells; it disrupts prophase, results in a dramatic shortening of the mitotic chromosome axis, and leads to abnormal INCENP localization. Our results imply phosphorylation of CAP-D3 acts to limit condensin II binding onto mitotic chromosomes. We present the first in vivo example that alters the ratio of condensin I:II on mitotic chromosomes. Our results demonstrate this ratio is a critical determinant in shaping mitotic chromosomes.

  4. Controlling Surface Ligand Density and Core Size of Alkanethiolate-Capped Pd Nanoparticles and Their Effects on Catalysis

    PubMed Central

    Gavia, Diego J.; Shon, Young-Seok

    2016-01-01

    This article presents systematic investigations on the relationship between the catalytic property and the surface ligand density/core size of thiolate ligand-capped Pd nanoparticles (PdNPs). The systematic variations in the two-phase synthesis of PdNPs generated from sodium S-dodecylthiosulfate were performed. The resulting PdNPs were characterized by transmission electron microscopy (TEM), thermogravimetric analysis (TGA), and 1H NMR and UV–vis spectroscopy. The decrease in the molar equivalent of sodium S-dodecylthiosulfate (Bunte salts) resulted in the formation of nanoparticles with lower surface ligand density and larger particle core size. A decrease in the molar equivalent of tetra-n-octylammonium bromide or an increase in reaction temperature generated nanoparticles with higher surface ligand density and smaller particle core size. As the molar equivalent of NaBH4 decreased, the particle core size increased. The catalysis studies on various PdNPs with different surface ligand density and average core size showed a strong correlation between the PdNP composition and the turnover frequency (TOF) of the isomerization of allyl alcohol. Optimized “good” PdNPs with lower surface ligand coverage and larger core size catalyzed the isomerization of various allyl alcohols to carbonyl analogues with high activity and selectivity. PMID:22924990

  5. Ability of combined Near-Infrared Spectroscopy-Intravascular Ultrasound (NIRS-IVUS) imaging to detect lipid core plaques and estimate cap thickness in human autopsy coronary arteries

    NASA Astrophysics Data System (ADS)

    Grainger, S. J.; Su, J. L.; Greiner, C. A.; Saybolt, M. D.; Wilensky, R. L.; Raichlen, J. S.; Madden, S. P.; Muller, J. E.

    2016-03-01

    The ability to determine plaque cap thickness during catheterization is thought to be of clinical importance for plaque vulnerability assessment. While methods to compositionally assess cap integrity are in development, a method utilizing currently available tools to measure cap thickness is highly desirable. NIRS-IVUS is a commercially available dual imaging method in current clinical use that may provide cap thickness information to the skilled reader; however, this is as yet unproven. Ten autopsy hearts (n=15 arterial segments) were scanned with the multimodality NIRS-IVUS catheter (TVC Imaging System, Infraredx, Inc.) to identify lipid core plaques (LCPs). Skilled readers made predictions of cap thickness over regions of chemogram LCP, using NIRS-IVUS. Artery segments were perfusion fixed and cut into 2 mm serial blocks. Thin sections stained with Movat's pentachrome were analyzed for cap thickness at LCP regions. Block level predictions were compared to histology, as classified by a blinded pathologist. Within 15 arterial segments, 117 chemogram blocks were found by NIRS to contain LCP. Utilizing NIRSIVUS, chemogram blocks were divided into 4 categories: thin capped fibroatheromas (TCFA), thick capped fibroatheromas (ThCFA), pathological intimal thickening (PIT)/lipid pool (no defined cap), and calcified/unable to determine cap thickness. Sensitivities/specificities for thin cap fibroatheromas, thick cap fibroatheromas, and PIT/lipid pools were 0.54/0.99, 0.68/0.88, and 0.80/0.97, respectively. The overall accuracy rate was 70.1% (including 22 blocks unable to predict, p = 0.075). In the absence of calcium, NIRS-IVUS imaging provided predictions of cap thickness over LCP with moderate accuracy. The ability of this multimodality imaging method to identify vulnerable coronary plaques requires further assessment in both larger autopsy studies, and clinical studies in patients undergoing NIRS-IVUS imaging.

  6. Penny ice cap cores, baffin island, canada, and the wisconsinan foxe dome connection: two states of hudson bay ice cover

    PubMed

    Fisher; Koerner; Bourgeois; Zielinski; Wake; Hammer; Clausen; Gundestrup; Johnsen; Goto-Azuma; Hondoh; Blake; Gerasimoff

    1998-01-30

    Ice cores from Penny Ice Cap, Baffin Island, Canada, provide continuous Holocene records of oxygen isotopic composition (delta18O, proxy for temperature) and atmospheric impurities. A time scale was established with the use of altered seasonal variations, some volcanic horizons, and the age for the end of the Wisconsin ice age determined from the GRIP and GISP2 ice cores. There is pre-Holocene ice near the bed. The change in delta18O since the last glacial maximum (LGM) is at least 12.5 per mil, compared with an expected value of 7 per mil, suggesting that LGM ice originated at the much higher elevations of the then existing Foxe Dome and Foxe Ridge of the Laurentide Ice Sheet. The LGM delta18O values suggest thick ice frozen to the bed of Hudson Bay.

  7. Penny ice cap cores, baffin island, canada, and the wisconsinan foxe dome connection: two states of hudson bay ice cover

    PubMed

    Fisher; Koerner; Bourgeois; Zielinski; Wake; Hammer; Clausen; Gundestrup; Johnsen; Goto-Azuma; Hondoh; Blake; Gerasimoff

    1998-01-30

    Ice cores from Penny Ice Cap, Baffin Island, Canada, provide continuous Holocene records of oxygen isotopic composition (delta18O, proxy for temperature) and atmospheric impurities. A time scale was established with the use of altered seasonal variations, some volcanic horizons, and the age for the end of the Wisconsin ice age determined from the GRIP and GISP2 ice cores. There is pre-Holocene ice near the bed. The change in delta18O since the last glacial maximum (LGM) is at least 12.5 per mil, compared with an expected value of 7 per mil, suggesting that LGM ice originated at the much higher elevations of the then existing Foxe Dome and Foxe Ridge of the Laurentide Ice Sheet. The LGM delta18O values suggest thick ice frozen to the bed of Hudson Bay. PMID:9445472

  8. Msh2 deficiency leads to chromosomal abnormalities, centrosome amplification, and telomere capping defect

    SciTech Connect

    Wang, Yisong; Liu, Yie

    2006-01-01

    Msh2 is a key mammalian DNA mismatch repair (MMR) gene and mutations or deficiencies in mammalian Msh2 gene result in microsatellite instability (MSI+) and the development of cancer. Here, we report that primary mouse embryonic fibroblasts (MEFs) deficient in the murine MMR gene Msh2 (Msh2-/-) showed a significant increase in chromosome aneuploidy, centrosome amplification, and defective mitotic spindle organization and unequal chromosome segregation. Although Msh2-/- mouse tissues or primary MEFs had no apparent change in telomerase activity, telomere length, or recombination at telomeres, Msh2-/- MEFs showed an increase in chromosome end-to-end fusions or chromosome ends without detectable telomeric DNA. These data suggest that MSH2 helps to maintain genomic stability through the regulation of the centrosome and normal telomere capping in vivo and that defects in MMR can contribute to oncogenesis through multiple pathways.

  9. Ice core from Akademii Nauk ice cap, Severnaya Zemlya (Russian Arctic), dated with a Nye model modified for a growing glacier

    NASA Astrophysics Data System (ADS)

    Fritzsche, Diedrich; Opel, Thomas; Meyer, Hanno

    2010-05-01

    From 1999 to 2001 a 724 m deep ice core has been drilled from surface to bedrock close to summit of the Akademii Nauk ice cap, Severnaya Zemlya (Russian Arctic), within a joint German-Russian project. The analysis of stable water isotopes and major ion concentration in high resolution were used for reconstruction of past climate and environmental changes. The upper 304 m of the core were dated by counting annual stable isotope cycles considering radioactive (1986, 1963) and volcanic events (1956, 1912, 1783, 1259) as reference horizons. The resulting depth-age relationship and the corresponding annual-layer thickness imply that the ice cap was not in dynamic steady state but had been growing until recent times. That does not comply with requirements of a standard Nye or Dansgaard-Johnson flow model approach. To take into account the peculiarities of Akademii Nauk ice cap a Nye model was modified by adding a growing term according to the found relationship between annual layer thickness and depth. Using the volcanoes identified an average increase of altitude of about 0.08 m w.e. per year was calculated since AD 1259. The model enables us to reconstruct the altitude changes of the ice cap with time and to consider an altitude effect to correct the stable isotope values and to explain decreasing sea-salt ion data. Using the suggested model annual layer thickness can be decompressed to accumulation rates at the altitude where the precipitation was originally deposited. The model can also be used for dating deeper parts of ice core where volcanoes are not identified up to now. Applying this model, the ice core has an age of about 2 500 years, much less than claimed for an older core from Akademii Nauk ice cap. Consequently, the ice cap is much younger and only of Late Holocene age, as also assumed for most Arctic ice caps and glaciers outside Greenland. However, the lowest part of Akademii Nauk ice cap is probably a remnant of an older ice cap stage.

  10. Effects of zinc, copper, and lead toxicity on. cap alpha. -aminolevulinic acid dehydratase activity. [Rats

    SciTech Connect

    Shafiq-ur-Rehman

    1984-07-01

    The distribution of lead, zinc and copper in the human environment has been recognized as a major toxicological factor. Lead ions have been shown to inhibit the activity of delta-aminolevulinic acid dehydratase (delta-ALAD), which is involved in the biosynthesis of heme. Copper also has its inhibitory effect on delta-ALAD activity. A study has shown that the delta-ALAD was activated by zinc ions at physiological concentrations. In view of these reports, it was considered worthwhile to study the poisoning effects of lead, zinc and copper on delta-ALAD activity along with the concentrations of these metal ions in the blood. A possible role of Zn/sup + +/, Cu/sup + +/, and Pb/sup + +/ interaction and their influence on delta-ALAD has been explored in the present paper.

  11. Highly efficient siRNA delivery from core-shell mesoporous silica nanoparticles with multifunctional polymer caps

    NASA Astrophysics Data System (ADS)

    Möller, Karin; Müller, Katharina; Engelke, Hanna; Bräuchle, Christoph; Wagner, Ernst; Bein, Thomas

    2016-02-01

    A new general route for siRNA delivery is presented combining porous core-shell silica nanocarriers with a modularly designed multifunctional block copolymer. Specifically, the internal storage and release of siRNA from mesoporous silica nanoparticles (MSN) with orthogonal core-shell surface chemistry was investigated as a function of pore-size, pore morphology, surface properties and pH. Very high siRNA loading capacities of up to 380 μg per mg MSN were obtained with charge-matched amino-functionalized mesoporous cores, and release profiles show up to 80% siRNA elution after 24 h. We demonstrate that adsorption and desorption of siRNA is mainly driven by electrostatic interactions, which allow for high loading capacities even in medium-sized mesopores with pore diameters down to 4 nm in a stellate pore morphology. The negatively charged MSN shell enabled the association with a block copolymer containing positively charged artificial amino acids and oleic acid blocks, which acts simultaneously as capping and endosomal release agent. The potential of this multifunctional delivery platform is demonstrated by highly effective cell transfection and siRNA delivery into KB-cells. A luciferase reporter gene knock-down of up to 80-90% was possible using extremely low cell exposures with only 2.5 μg MSN containing 0.5 μg siRNA per 100 μL well.A new general route for siRNA delivery is presented combining porous core-shell silica nanocarriers with a modularly designed multifunctional block copolymer. Specifically, the internal storage and release of siRNA from mesoporous silica nanoparticles (MSN) with orthogonal core-shell surface chemistry was investigated as a function of pore-size, pore morphology, surface properties and pH. Very high siRNA loading capacities of up to 380 μg per mg MSN were obtained with charge-matched amino-functionalized mesoporous cores, and release profiles show up to 80% siRNA elution after 24 h. We demonstrate that adsorption and desorption of

  12. Mechanistic insight into the nucleation and growth of oleic acid capped lead sulphide quantum dots.

    PubMed

    Shrestha, Aabhash; Spooner, Nigel A; Qiao, Shi Zhang; Dai, Sheng

    2016-05-18

    The quantum dots (QDs) of lead sulphide (PbS) are attractive near-infrared (NIR) active materials and have promising applications in a wide variety of applications. Till date many efforts have been made on optimizing its synthesis; however, current mechanistic understanding involving the nucleation and growth of these QDs has not reached the same level as that for other QDs. In this study, we present a detailed understanding on synthesis mechanism of PbS QDs so as to provide guidance for future QDs synthesis. The synthesis of PbS QDs is largely independent of classical nucleation process and the hot-injection of precursors may not be necessary for the successful synthesis of PbS QDs. The synthesis is basically a growth dominated process and is controlled by the Ostwald ripening of PbS QDs. In addition, reaction temperature and ligand are the key parameters for controlling QD growth. Temperature provides energy for overcoming activation barrier of QD growth while the ligands enhance QD growth via altering the environment for QD growth. Following the mechanism governing the synthesis of PbS QDs, we demonstrate that the size tuning of PbS QDs in ultra-small (<2 nm) can be achieved, which has been typically challenging following the hot injection synthesis.

  13. Mechanistic insight into the nucleation and growth of oleic acid capped lead sulphide quantum dots.

    PubMed

    Shrestha, Aabhash; Spooner, Nigel A; Qiao, Shi Zhang; Dai, Sheng

    2016-05-18

    The quantum dots (QDs) of lead sulphide (PbS) are attractive near-infrared (NIR) active materials and have promising applications in a wide variety of applications. Till date many efforts have been made on optimizing its synthesis; however, current mechanistic understanding involving the nucleation and growth of these QDs has not reached the same level as that for other QDs. In this study, we present a detailed understanding on synthesis mechanism of PbS QDs so as to provide guidance for future QDs synthesis. The synthesis of PbS QDs is largely independent of classical nucleation process and the hot-injection of precursors may not be necessary for the successful synthesis of PbS QDs. The synthesis is basically a growth dominated process and is controlled by the Ostwald ripening of PbS QDs. In addition, reaction temperature and ligand are the key parameters for controlling QD growth. Temperature provides energy for overcoming activation barrier of QD growth while the ligands enhance QD growth via altering the environment for QD growth. Following the mechanism governing the synthesis of PbS QDs, we demonstrate that the size tuning of PbS QDs in ultra-small (<2 nm) can be achieved, which has been typically challenging following the hot injection synthesis. PMID:27156571

  14. Avidin-biotin capped mesoporous silica nanoparticles as an ion-responsive release system to determine lead(II).

    PubMed

    Song, Weiling; Li, Jingyu; Li, Qing; Ding, Wenyao; Yang, Xiaoyan

    2015-02-15

    We have developed DNAzyme-functionalized silica nanoparticles for the rapid, sensitive, and selective detection of lead ion (Pb(2+)). The specific binding between avidin and biotinylated DNAzymes was used to cap the pore of dye-trapped silica nanoparticles. In the presence of Pb(2+), DNAzymes were catalytically cleaved to uncap the pore, releasing the dye cargo with detectable enhancements of fluorescence signal. This method enables rapid (15 min) and sensitive (limit of detection=8.0 nM) detection. Moreover, the Pb(2+)-responsive behavior shows high selectivity with other metal ions. The superior properties of the as-designed DNAzyme-functionalized silica nanoparticles can be attributed to the large loading capacity and highly ordered pore structure of mesoporous silica nanoparticles as well as the catalytical cleaving of DNAzymes with Pb(2+). The recoveries obtained by standard Pb(II) addition to real samples-tap water, commercial mineral water, and lake water-were all from 98 to 101%. Our design serves as a new prototype for metal-ion sensing systems, and it also has promising potential for detection of various targets in stimulus-release systems. PMID:25447495

  15. The lead isotopic age of the Earth can be explained by core formation alone.

    PubMed

    Wood, Bernard J; Halliday, Alex N

    2010-06-10

    The meaning of the age of the Earth defined by lead isotopes has long been unclear. Recently it has been proposed that the age of the Earth deduced from lead isotopes reflects volatile loss to space at the time of the Moon-forming giant impact rather than partitioning into metallic liquids during protracted core formation. Here we show that lead partitioning into liquid iron depends strongly on carbon content and that, given a content of approximately 0.2% carbon, experimental and isotopic data both provide evidence of strong partitioning of lead into the core throughout the Earth's accretion. Earlier conclusions that lead is weakly partitioned into iron arose from the use of carbon-saturated (about 5% C) iron alloys. The lead isotopic age of the Earth is therefore consistent with partitioning into the core and with no significant late losses of moderately volatile elements to space during the giant impact.

  16. Glycerol capped PbS/CdS core/shell nanoparticles at different molar ratio and its application in biosensors: An optical properties study

    NASA Astrophysics Data System (ADS)

    Das, D.; Hussain, A. M. P.

    2016-05-01

    Glycerol capped PbS/CdS core/shell type nanoparticles fabricated with two different molar ratios are characterized for study of structural and optical properties. The X-ray diffraction (XRD) pattern exhibits cubic phased polycrystalline nanocrystals. The calculated grain sizes from Williamson-Hall plot were found to be around 6 nm with increased strain. HRTEM investigation confirms the formation of core/shell nanostructures and the sizes of the particles were found to be around 7 nm which is in good agreement with the results of the W-H plot. An increase of band gap with the decrease in precursor concentration is confirmed from the blue shift in the absorption spectra and also from Tauc plot. A clear blue shifted intense emission is observed in the photoluminescence spectra with decrease in particle size. Intense luminescence from the core/shell nanostructure may be applied in bio labelling and biosensors.

  17. Numerical prediction of vortex cores of the leading and trailing edges of delta wings

    NASA Technical Reports Server (NTRS)

    Kandil, O. A.

    1980-01-01

    The purpose of the present paper is to predict the roll-up of the vortex sheets emanating from the leading- and trailing-edges of delta wings with emphasis on the interaction of vortex cores beyond the trailing edge. The motivation behind the present work is the recent experimental data published by Hummel. The Nonlinear Discrete-Vortex method (NDV-method) is modified and extended to predict the leading- and trailing-vortex cores beyond the trailing edge. The present model alleviates the problems previously encountered in predicting satisfactory pressure distributions. This is accomplished by lumping the free-vortex lines during the iteration procedure. The leading- and trailing-edge cores and their feeding sheets are obtained as parts of the solution. The numerical results show that the NDV-method is successful in confirming the formation of a trailing-edge core with opposite circulation and opposite roll-up to those of the leading-edge core. This work is a breakthrough in the high angle of attack aerodynamics and moreover, it is the first numerical prediction done on this problem

  18. Synthesis, characterization and electrochemical characterization of lead selenide sub-micron particles capped with a benzoate ligand and prepared at different temperatures

    NASA Astrophysics Data System (ADS)

    Rodríguez-Rodríguez, Weyshla A.; Colón, Jadiel; Guzmán, Roger; Rivera, Harry; Santiago-Berríos, Mitk'El B.

    2014-09-01

    Semiconductor materials offer several potential benefits as active elements in the development of harvesting-energy conversion technologies. In particular, lead selenide (PbSe) semiconductors have been used and proposed to design solar energy harvesting devices, IR sensors, FET devices, etc. Lead salts have drawn particular attention from the applied and fundamental research communities due to their exceptionally strong quantum confinement effects. Several syntheses of PbSe have been proposed using long chain surfactants to allow the formation of particles and nanoparticles. Here we present a synthesis using benzoic acid as the capping ligand in ambient atmosphere. Although the particles are not in nanometric size, we compare the crystal structure (using x-ray powder diffraction data), the near infrared and mid-infrared absorption properties of PbSe using oleic acid as the capping ligand with PbSe using benzoic acid as the capping ligand. The new synthetized particles were shown to have similar crystal structure and absorb light in the near infrared region at 1410 nm. We also performed cyclic voltammetry of these particles drop-casted in the surface of a glassy carbon electrode. The particles showed electrochemical behavior with an oxidation peak near (-402 ± 5 mV) versus Ag/AgCl reference electrode. The particles seem to form a polymeric film at the surface of a glassy carbon electrode.

  19. Core Practices and Problems of Practice in Learning to Lead Classroom Discussions

    ERIC Educational Resources Information Center

    Ghousseini, Hala

    2015-01-01

    Given the current interest in organizing teacher education around core instructional practices that help preservice teachers enact ambitious aspects of teaching like leading classroom discussions, this article investigates an example from the experience of a preservice teacher as she works on orienting students to each other's ideas. Resulting…

  20. Highly stable, luminescent core-shell type methylammonium-octylammonium lead bromide layered perovskite nanoparticles.

    PubMed

    Bhaumik, Saikat; Veldhuis, Sjoerd A; Ng, Yan Fong; Li, Mingjie; Muduli, Subas Kumar; Sum, Tze Chien; Damodaran, Bahulayan; Mhaisalkar, Subodh; Mathews, Nripan

    2016-06-01

    A new protocol for the synthesis of a highly stable (over 2 months under ambient conditions) solution-processed core-shell type structure of mixed methylammonium-octylammonium lead bromide perovskite nanoparticles (5-12 nm), having spherical shape, color tunability in the blue to green spectral region (438-521 nm) and a high photoluminescence quantum yield (PLQY) of up to 92% is described. The color tunability, high PLQY and stability are due to the quantum confinement imparted by the crystal engineering associated with core-shell nanoparticle formation during growth. PMID:27165565

  1. Lead cleavage sites in the core structure of group I intron-RNA.

    PubMed Central

    Streicher, B; von Ahsen, U; Schroeder, R

    1993-01-01

    Self-splicing of group I introns requires divalent metal ions to promote catalysis as well as for the correct folding of the RNA. Lead cleavage has been used to probe the intron RNA for divalent metal ion binding sites. In the conserved core of the intron, only two sites of Pb2+ cleavage have been detected, which are located close to the substrate binding sites in the junction J8/7 and at the bulged nucleotide in the P7 stem. Both lead cleavages can be inhibited by high concentrations of Mg2+ and Mn2+ ions, suggesting that they displace Pb2+ ions from the binding sites. The RNA is protected from lead cleavage by 2'-deoxyGTP, a competitive inhibitor of splicing. The two major lead induced cleavages are both located in the conserved core of the intron and at phosphates, which had independently been demonstrated to interact with magnesium ions and to be essential for splicing. Thus, we suggest that the conditions required for lead cleavage occur mainly at those sites, where divalent ions bind that are functionally involved in catalysis. We propose lead cleavage analysis of functional RNA to be a useful tool for mapping functional magnesium ion binding sites. Images PMID:7680116

  2. Introduction of the human pro. cap alpha. 1(I) collagen gene into pro. cap alpha. 1(I)-deficient Mov-13 mouse cells leads to formation of functional mouse-human hybrid type I collagen

    SciTech Connect

    Schnieke, A.; Dziadek, M.; Bateman, J.; Mascara, T.; Harbers, K.; Gelinas, R.; Jaenisch, R.

    1987-02-01

    The Mov-13 mouse strain carries a retroviral insertion in the pro..cap alpha..1(I) collagen gene that prevents transcription of the gene. Cell lines derived from homozygous embryos do not express type I collagen although normal amounts of pro..cap alpha..2 mRNA are synthesized. The authors have introduced genomic clones of either the human or mouse pro..cap alpha..1(I) collagen gene into homozygous cell lines to assess whether the human or mouse pro..cap alpha..1(I) chains can associate with the endogenous mouse pro..cap alpha..2(I) chain to form stable type I collagen. The human gene under control of the simian virus 40 promoter was efficiently transcribed in the transfected cells. Protein analyses revealed that stable heterotrimers consisting of two human ..cap alpha..1 chains and one mouse ..cap alpha..2 chain were formed and that type I collagen was secreted by the transfected cells at normal rates. However, the electrophoretic migration of both ..cap alpha..1(I) and ..cap alpha..2(I) chains in the human-mouse hybrid molecules were retarded, compared to the ..cap alpha..(I) chains in control mouse cells. Inhibition of the posttranslational hydroxylation of lysine and proline resulted in comigration of human and mouse ..cap alpha..1 and ..cap alpha..2 chains, suggesting that increased posttranslational modification caused the altered electrophoretic migration in the human-mouse hybrid molecules. Amino acid sequence differences between the mouse and human ..cap alpha.. chains may interfere with the normal rate of helix formation and increase the degree of posttranslational modifications similar to those observed in patients with lethal perinatal osteogenesis imperfecta. The Mov-13 mouse system should allow the authors to study the effect specific mutations introduced in transfected pro..cap alpha..1(I) genes have on the synthesis, assembly, and function of collagen I.

  3. CArG boxes in the human cardiac. cap alpha. -actin gene are core binding sites for positive trans-acting regulatory factors

    SciTech Connect

    Miwa, T.; Boxer, L.M.; Kedes, L.

    1987-10-01

    Positively acting, rate-limiting regulatory factors that influence tissue-specific expression of the human cardiac ..cap alpha..-actin gene in a mouse muscle cell line are shown by in vivo competition and gel mobility-shift assays to bind to upstream regions of its promoter but to neither vector DNA not a ..beta..-globin promoter. Although the two binding regions are distinctly separated, each corresponds to a cis region required for muscle-specific transcriptional stimulation, and each contains a core CC(A+T-rich)/sub 6/GC sequence (designated CArG box), which is found in the promoter regions of several muscle-associated genes. Each site has an apparently different binding affinity for trans-acting factors, which may explain the different transcriptional stimulation activities of the two cis regions. Therefore, the authors conclude that the two CArG box regions are responsible for muscle-specific transcriptional activity of the cardiac ..cap alpha..-actin gene through a mechanism that involves their binding of a positive trans-acting factor in muscle cells.

  4. Photogenerated carriers transport behaviors in L-cysteine capped ZnSe core-shell quantum dots

    NASA Astrophysics Data System (ADS)

    Shan, Qingsong; Li, Kuiying; Xue, Zhenjie; Lin, Yingying; Yin, Hua; Zhu, Ruiping

    2016-02-01

    The photoexcited carrier transport behavior of zinc selenide (ZnSe) quantum dots (QDs) with core-shell structure is studied because of their unique photoelectronic characteristics. The surface photovoltaic (SPV) properties of self-assembled ZnSe/ZnS/L-Cys core-shell QDs were probed via electric field induced surface photovoltage and transient photovoltage (TPV) measurements supplemented by Fourier transform infrared, laser Raman, absorption, and photoluminescence spectroscopies. The ZnSe QDs displayed p-type SPV characteristics with a broader stronger SPV response over the whole ultraviolet-to-near-infrared range compared with those of other core-shell QDs in the same group. The relationship between the SPV phase value of the QDs and external bias was revealed in their SPV phase spectrum. The wide transient photovoltage response region from 3.3 × 10-8 to 2 × 10-3 s was closely related to the long diffusion distance of photoexcited free charge carriers in the interfacial space-charge region of the QDs. The strong SPV response corresponding to the ZnSe core mainly originated from an obvious quantum tunneling effect in the QDs.

  5. Reduced Biosynthesis of Digalactosyldiacylglycerol, a Major Chloroplast Membrane Lipid, Leads to Oxylipin Overproduction and Phloem Cap Lignification in Arabidopsis.

    PubMed

    Lin, Yang-Tsung; Chen, Lih-Jen; Herrfurth, Cornelia; Feussner, Ivo; Li, Hsou-Min

    2016-01-01

    DIGALACTOSYLDIACYLGLYCEROL SYNTHASE1 (DGD1) is a chloroplast outer membrane protein responsible for the biosynthesis of the lipid digalactosyldiacylglycerol (DGDG) from monogalactosyldiacylglycerol (MGDG). The Arabidopsis thaliana dgd1 mutants have a greater than 90% reduction in DGDG content, reduced photosynthesis, and altered chloroplast morphology. However, the most pronounced visible phenotype is the extremely short inflorescence stem, but how deficient DGDG biosynthesis causes this phenotype is unclear. We found that, in dgd1 mutants, phloem cap cells were lignified and jasmonic acid (JA)-responsive genes were highly upregulated under normal growth conditions. The coronative insensitive1 dgd1 and allene oxide synthase dgd1 double mutants no longer exhibited the short inflorescence stem and lignification phenotypes but still had the same lipid profile and reduced photosynthesis as dgd1 single mutants. Hormone and lipidomics analyses showed higher levels of JA, JA-isoleucine, 12-oxo-phytodienoic acid, and arabidopsides in dgd1 mutants. Transcript and protein level analyses further suggest that JA biosynthesis in dgd1 is initially activated through the increased expression of genes encoding 13-lipoxygenases (LOXs) and phospholipase A-Iγ3 (At1g51440), a plastid lipase with a high substrate preference for MGDG, and is sustained by further increases in LOX and allene oxide cyclase mRNA and protein levels. Our results demonstrate a link between the biosynthesis of DGDG and JA. PMID:26721860

  6. Cervical Cap

    MedlinePlus

    ... and remove the cap. How Much Does It Cost? A cervical cap costs about $70 and should be replaced every year. In addition, there is also the cost of the doctor's visit. Many health insurance plans ...

  7. A theory for the core flow of leading-edge vortices

    NASA Technical Reports Server (NTRS)

    Luckring, James M.

    1986-01-01

    Separation-induced leading-edge vortices can dominate the flow about slender wings at moderate to high angles of attack, often with favorable aerodynamic effects. However, at the high angles of attack which are desirable for takeoff and landing as well as subsonic-transonic maneuver the vortices can breakdown or burst in the vicinity of the aircraft causing many adverse effects; these include lift loss, pitchup, and buffet. The flow in the core of leading-edge vortices is generally affiliated with the vortex breakdown phenomenon. A theory is presented for the flow in the core of separation-induced, leading-edge vortices at practical Reynolds numbers. The theory is based on matching inner and outer representations of the vortex. The inner representation models continuously distributed vorticity and includes an asymptotic viscous subcore. The outer representation models concentrated spiral sheets of vorticity and is fully three dimensional. A parameter is identified which closely tracks the vortex breakdown stability boundary for delta, arrow, and diamond wings.

  8. A sensitive electrochemiluminescence immunosensor based on luminophore capped Pd@Au core-shell nanoparticles as signal tracers and ferrocenyl compounds as signal enhancers.

    PubMed

    Liu, Yuting; Wang, Haijun; Xiong, Chengyi; Yuan, Yali; Chai, Yaqin; Yuan, Ruo

    2016-07-15

    In this work, N-(aminobutyl)-N-(ethylisoluminol) (ABEI), an analogue of luminol, is served as both the reductant and luminescence reagent to synthesize ABEI capped Pd@Au core-shell nanoparticles (ABEI-Pd@AuNPs). The nanoparticles not only exhibit inherent electrochemiluminescence (ECL) property, but also possess advantages of noble-metal nanomaterials such as outstanding electronic property, high specific surface area and good biocompatibility. In order to enhance the luminescence efficiency, ferrocene monocarboxylic acid (Fc) as catalyzer is grafted on the surface of ABEI-Pd@AuNPs with the aid of l-cysteine (l-Cys). When the Fc is electrochemically oxidized to ferricinium cation species (Fc(+)), the decomposition of H2O2 which existed in detection solution can be catalyzed by Fc(+) to generate oxygen-related free radicals, resulting effective signal amplification for ABEI-H2O2 system. For potential applications, the Pd@Au core-shell nanoparticles bifunctionalized by ABEI and catalyzer are employed as nano-carriers to immobilize detection antibody (Ab2). Based on sandwiched immunoreactions, a "signal-on" ECL immunosensor is developed for detection of human collagen type IV (Col IV), a potential biomarker associated with diabetic nephropathy. Consequently, the proposed immunosensor provides a wide linear detection ranging from 1pgmL(-1) to 10ngmL(-1) with a relatively low detection limit of 0.3pgmL(-1) (S/N=3). PMID:26985586

  9. Assessing post-depositional alteration and the integrity of ice core nitrate-N and -O isotopic records at the Quelccaya Ice Cap, Peru

    NASA Astrophysics Data System (ADS)

    Buffen, A. M.; Hastings, M. G.; Thompson, L. G.; Mosley-Thompson, E. S.

    2011-12-01

    Nitrate (NO3-) is a common chemical species found in snow and ice. Both nitrate and its atmospheric precursor NOx (NO and NO2) are of importance to climate, biogeochemistry and the composition of the atmosphere. For instance, nitrate is a critical biological nutrient, while NOx regulates concentrations of ozone (O3) and hydroxyl (OH) and thus influences the chemical and radiative properties of Earth's atmosphere. NOx sources include fossil fuel combustion, biomass burning, soil microbial processes and lightning. Past changes in NOx emissions, tropospheric distributions and consequent effects on the atmosphere, however, are unknown. Interpreting stable nitrogen (δ15N) and oxygen (δ18O and Δ17O) isotope ratios in nitrate preserved in ice cores can address these issues as they contain diagnostic signatures of NOx sources and oxidation processes, respectively. The potential caveat to this is that nitrate can be lost from snow and firn via photolysis (as NOx) and/or volatilization (as nitric acid). Because these processes are isotopically fractionating, it is necessary to determine if, or to what degree, such post-depositional alteration takes place at a given site before an isotopic record from ice core nitrate can be utilized as a paleoenvironmental proxy. This work addresses post-depositional alteration at the Quelccaya Ice Cap (5670 masl) in southeastern Peru in order to assess the integrity of the nitrate record in an 1800-year ice core from the site. This work represents the first of its kind outside the polar regions and is significant in that natural NOx sources and OH production are dominantly located in the Tropics. Additionally, because nitrate and NOx are not uniformly distributed in the troposphere, low-latitude records are needed to bridge ongoing polar work in order to establish a global perspective.

  10. The GUINEVERE experiment: First PNS measurements in a lead moderated sub-critical fast core

    SciTech Connect

    Thyebault, H. E.; Billebaud, A.; Chabod, S.; Lecolley, F. R.; Lecouey, J. L.; Lehaut, G.; Marie, N.; Ban, G.

    2012-07-01

    The GUINEVERE (Generation of Uninterrupted Intense Neutrons at the lead Venus Reactor) experimental program is dedicated to the study of Accelerator Driven System reactivity monitoring. It was partly carried out within the EUROTRANS integrated project (EURATOM FP6). GUINEVERE consists in coupling the fast core of the VENUS-F reactor (SCK-CEN, Mol (Belgium)), composed of enriched uranium and solid lead, with a T(d,n) neutron source provided by the GENEPI-3C deuteron accelerator. This neutron source can be operated in several modes: pulsed mode, continuous mode and also continuous mode with short beam interruptions (the so called 'beam trips'). In the past, the key questions of the reactivity control and monitoring in a subcritical system were studied in the MUSE experiments (1998-2004). These experiments highlighted the difficulty to determine precisely the reactivity with a single technique. This led to investigate a new strategy which is based on the combination of the relative reactivity monitoring via the core power to beam current relationship with absolute reactivity cross-checks during programmed beam interruptions. Consequently, to determine the reactivity, several dynamical techniques of reactivity determination have to be compared. In addition, their accuracy for absolute reactivity determination must be evaluated using a reference reactivity determination technique (from a critical state: rod drop and MSM measurements). The first sub-critical configuration which was studied was around k{sub eff} = 0.96 (SCI). Pulsed Neutron Source experiments (PNS) were carried out. The neutron population decrease was measured using fission chambers in different locations inside the core and the reflector. Neutron population time decrease was analyzed using fitting techniques and the Area Method Results obtained for the SCI reactivity will be shown, discussed and compared to the reference value given by the MSM method. (authors)

  11. Studies Conducted of Sodium Carbonate Contaminant Found on the Wing Leading Edge and the Nose Cap of the Space Shuttle Orbiter

    NASA Technical Reports Server (NTRS)

    Jacobson, Nathan S.; Palou, Jaime J.

    2003-01-01

    In early 2001, three of the space shuttle orbiters were found to have a sodium carbonate contaminant on the wing leading edge and nose cap. These parts are made of a reinforced carbon/carbon material protected by silicon carbide (SiC) and a glass coating. The glass coating is known as Type A and is primarily sodium silicate with particles of SiC. NASA Glenn Research Center's Environmental Durability Branch was asked to determine the chemistry of this deposit formation and assess any possible detrimental effects. At low temperatures, the reverse reaction is favorable. Previous studies of the corrosion of glass show that carbon dioxide in the presence of water does form sodium carbonate on sodium silicate glass (ref. 1). It is quite likely that a similar scenario exists for the orbiter wing leading edge. All three orbiters that formed sodium carbonate were exposed to rain. This formation of sodium carbonate was duplicated in the laboratory. The Type A glass, which coats the wing leading edge and nose cap, was made in a freestanding form and exposed to water in two separate experiments. In one set of experiments, the coating was placed in a petri dish filled with water. As the water evaporated, sodium carbonate formed. In another case, water was slowly dripped on the coating and sodium carbonate formed. The sodium carbonate was detected by chemical analysis and, in some cases, xray diffraction showed a hydrated sodium carbonate. The next step was to examine possible detrimental effects of this sodium carbonate. There are three likely scenarios for the sodium carbonate deposit: (1) it may be removed with a simple rinse, (2) it may remain and flow back into the Type A glass after heating during reentry, or (3) it may remain and flow onto unprotected SiC and/or other parts after heating during reentry. The effect of case 1 is to remove the Na2O constituent from the Type A glass, thus decreasing its effectiveness as a sealant. Even so, overall, it is probably the best

  12. Engineering of lead chalcogenide nanostructures for carrier multiplication: Core/shell, 1D, and 2D

    NASA Astrophysics Data System (ADS)

    Lin, Qianglu

    Near infrared emitting semiconductors have been used widely in industry especially in solar-cell fabrications. The efficiency of single junction solar-cell can reach the Shockley-Queisser limit by using optimum band gap material such as silicon and cadmium telluride. The theoretical efficiency can be further enhanced through carrier multiplication, in which a high energy photon is absorbed and more than one electron-hole pair can be generated, reaching more than 100% quantum efficiency in the high energy region of sunlight. The realization of more than unity external quantum efficiency in lead selenide quantum dots solar cell has motivated vast investigation on lowering the carrier multiplication threshold and further improving the efficiency. This dissertation focuses on synthesis of lead chalcogenide nanostructures for their optical spectroscopy studies. PbSe/CdSe core/shell quantum dots were synthesized by cation exchange to obtain thick shells (up to 14 monolayers) for studies of visible and near infrared dual band emissions and carrier multiplication efficiency. By examining the reaction mechanism, a thermodynamic and a kinetic model are introduced to explain the vacancy driven cation exchange. As indicated by the effective mass model, PbSe/CdSe core/shell quantum dots has quasi-type-II band alignment, possessing electron delocalized through the entire quantum dot and hole localized in the core, which breaks down the symmetry of energy levels in the conduction and valence band, leading to hot-hole-assisted efficient multi-exciton generation and a lower carrier multiplication threshold to the theoretical value. For further investigation of carrier multiplication study, PbTe, possessing the highest efficiency among lead chalcogenides due to slow intraband cooling, is synthesized in one-dimensional and two-dimensional nanostructures. By using dodecanethiol as the surfactant, PbTe NRs can be prepared with high uniformity in width and resulted in fine quantum

  13. Analysis of vanillic acid in polar ice cores as a biomass burning proxy - preliminary results from the Akademii Nauk Ice Cap in Siberia

    NASA Astrophysics Data System (ADS)

    Grieman, M. M.; Jimenez, R.; McConnell, J. R.; Fritzsche, D.; Saltzman, E. S.

    2013-12-01

    Biomass burning influences global climate change and the composition of the atmosphere. The drivers, effects, and climate feedbacks related to fire are poorly understood. Many different proxies have been used to reconstruct past fire frequency from lake sediments and polar ice cores. Reconstruction of historical trends in biomass burning is challenging because of regional variability and the qualitative nature of various proxies. Vanillic acid (4-hydroxy-3-methoxybenzoic acid) is a product of the combustion of conifer lignin that is known to occur in biomass burning aerosols. Biomass burning is likely the only significant source of vanillic acid in polar ice. In this study we describe an analytical method for quantifying vanillic acid in polar ice using HPLC with electrospray ionization and tandem mass spectrometric detection. The method has a detection limit of 100 pM and a precision of × 10% at the 100 pM level for analysis of 100 μl of ice melt water. The method was used to analyze more than 1000 discrete samples from the Akademii Nauk ice cap on Severnaya Zemlya in the high Russia Arctic (79°30'N, 97°45'E) (Fritzsche et al., 2002; Fritzsche et al., 2005; Weiler et al., 2005). The samples range in age over the past 2,000 years. The results show a mean vanillic acid concentration of 440 × 710 pM (1σ), with elevated levels during the periods from 300-600 and 1450-1550 C.E.

  14. The effect of varying the capping agent of magnetic/luminescent Fe3O4-InP/ZnSe core-shell nanocomposite

    NASA Astrophysics Data System (ADS)

    Paulsen, Zuraan; Onani, Martin O.; Allard, Garvin R. J.; Kiplagat, Ayabei; Okil, Joseph O.; Dejene, Francis B.; Mahanga, Geoffrey M.

    2016-01-01

    Magnetic-luminescent nanoparticles have shown great promise in various biomedical applications namely: contrast agents for magnetic resonance imaging, multifunctional drug carrier system, magnetic separation of cells, cell tracking, immunoassay, and magnetic bioseparation. This experiment describes the synthesis of a nanocomposite material, which is composed of an iron oxide (Fe3O4) superparamagnetic core and an indium phosphide/zinc selenide (InP/ZnSe) quantum dot shell. The magnetic nanoparticles (MNP's) and quantum dots (QD's) were synthesized separately before allowing them to conjugate. The MNP's were functionalized with a thiol-group allowing the QD shell to bind to the surface of the MNP by the formation of a thiol-metal bond. The nanocomposite was capped with 3-mercaptopropionic acid, oleylamine, β-cyclodextrin and their influence on the photoluminescence investigated. The synthesized nanocomposite was characterized with high- resolution transmission electron microscopy (HR-TEM), energy-dispersive spectroscopy (EDS), selective electron area diffraction (SAED), scanning electron microscopy (SEM), superconducting quantum interference device (SQUID), and photoluminescence. These techniques yielded particle size, morphology, dispersion, and chemical composition including luminescence and florescence.

  15. Core--strategy leading to high reversible hydrogen storage capacity for NaBH4.

    PubMed

    Christian, Meganne L; Aguey-Zinsou, Kondo-François

    2012-09-25

    Owing to its high storage capacity (10.8 mass %), sodium borohydride (NaBH(4)) is a promising hydrogen storage material. However, the temperature for hydrogen release is high (>500 °C), and reversibility of the release is unachievable under reasonable conditions. Herein, we demonstrate the potential of a novel strategy leading to high and stable hydrogen absorption/desorption cycling for NaBH(4) under mild pressure conditions (4 MPa). By an antisolvent precipitation method, the size of NaBH(4) particles was restricted to a few nanometers (<30 nm), resulting in a decrease of the melting point and an initial release of hydrogen at 400 °C. Further encapsulation of these nanoparticles upon reaction of nickel chloride at their surface allowed the synthesis of a core--shell nanostructure, NaBH(4)@Ni, and this provided a route for (a) the effective nanoconfinement of the melted NaBH(4) core and its dehydrogenation products, and (b) reversibility and fast kinetics owing to short diffusion lengths, the unstable nature of nickel borohydride, and possible modification of reaction paths. Hence at 350 °C, a reversible and steady hydrogen capacity of 5 mass % was achieved for NaBH(4)@Ni; 80% of the hydrogen could be desorbed or absorbed in less than 60 min, and full capacity was reached within 5 h. To the best of our knowledge, this is the first time that such performances have been achieved with NaBH(4). This demonstrates the potential of the strategy in leading to major advancements in the design of effective hydrogen storage materials from pristine borohydrides. PMID:22873406

  16. Core--strategy leading to high reversible hydrogen storage capacity for NaBH4.

    PubMed

    Christian, Meganne L; Aguey-Zinsou, Kondo-François

    2012-09-25

    Owing to its high storage capacity (10.8 mass %), sodium borohydride (NaBH(4)) is a promising hydrogen storage material. However, the temperature for hydrogen release is high (>500 °C), and reversibility of the release is unachievable under reasonable conditions. Herein, we demonstrate the potential of a novel strategy leading to high and stable hydrogen absorption/desorption cycling for NaBH(4) under mild pressure conditions (4 MPa). By an antisolvent precipitation method, the size of NaBH(4) particles was restricted to a few nanometers (<30 nm), resulting in a decrease of the melting point and an initial release of hydrogen at 400 °C. Further encapsulation of these nanoparticles upon reaction of nickel chloride at their surface allowed the synthesis of a core--shell nanostructure, NaBH(4)@Ni, and this provided a route for (a) the effective nanoconfinement of the melted NaBH(4) core and its dehydrogenation products, and (b) reversibility and fast kinetics owing to short diffusion lengths, the unstable nature of nickel borohydride, and possible modification of reaction paths. Hence at 350 °C, a reversible and steady hydrogen capacity of 5 mass % was achieved for NaBH(4)@Ni; 80% of the hydrogen could be desorbed or absorbed in less than 60 min, and full capacity was reached within 5 h. To the best of our knowledge, this is the first time that such performances have been achieved with NaBH(4). This demonstrates the potential of the strategy in leading to major advancements in the design of effective hydrogen storage materials from pristine borohydrides.

  17. Cradle cap

    MedlinePlus

    ... be prescribed. These may include medicated creams or shampoos. Most cases of cradle cap can be managed ... improve scalp circulation. Give your child daily, gentle shampoos with a mild shampoo as long as there ...

  18. Lead

    MedlinePlus

    ... Lead Share Facebook Twitter Google+ Pinterest Contact Us Lead Poisoning is Preventable If your home was built before ... of the RRP rule. Read more . Learn about Lead Poisoning Prevention Week . Report Uncertified Contractors and Environmental Violations ...

  19. Ultrasensitive and rapid lead sensing in water based on environmental friendly and high luminescent L-glutathione-capped-ZnSe quantum dots.

    PubMed

    Cai, Zhaoxia; Shi, Baoqin; Zhao, Lei; Ma, Meihu

    2012-11-01

    Water-soluble and high luminescent l-glutathione-capped-ZnSe quantum dots (QDs) were applied for ultrasensitive Pb(II) detection. l-glutathione-capped-ZnSe QDs were synthesized by a facile colloid aqueous phase route. It is characterized by transmission electron microscopy, X-ray powder diffraction spectrometry, Fourier transform infrared spectrometry, Ultraviolet-visible spectrometry and fluorescence spectrometry. Quantum yields of l-glutathione-capped-ZnSe QDs could reach 50.1% without post irradiation. The fluorescence quenching of the l-glutathione-capped-ZnSe QDs depended on the concentration, pH and reaction time of the Pb(II) solution. The possible mechanism of fluorescence of l-glutathione-capped-ZnSe QDs quenched by Pb(II) was discussed in detail. Under optimal conditions, the quenched fluorescence intensity increased linearly with the concentration of Pb(II) in the range of 1.0×10(-8)∼8.0×10(-7)mol/L. The limit of detection for Pb(II) was 0.71 nmol/L. This developed method is demonstrated to contain improved sensitive and selective characteristics for the detection of trace Pb(II) in water.

  20. Lead

    MedlinePlus

    ... obvious symptoms, it frequently goes unrecognized. CDC’s Childhood Lead Poisoning Prevention Program is committed to the Healthy People ... Lead Levels Information for Parents Tips for preventing lead poisoning About Us Overview of CDC’s Childhood Lead Poisoning ...

  1. Activation of a GPCR leads to eIF4G phosphorylation at the 5' cap and to IRES-dependent translation.

    PubMed

    León, Kelly; Boulo, Thomas; Musnier, Astrid; Morales, Julia; Gauthier, Christophe; Dupuy, Laurence; Heyne, Steffen; Backofen, Rolf; Poupon, Anne; Cormier, Patrick; Reiter, Eric; Crepieux, Pascale

    2014-06-01

    The control of mRNA translation has been mainly explored in response to activated tyrosine kinase receptors. In contrast, mechanistic details on the translational machinery are far less available in the case of ligand-bound G protein-coupled receptors (GPCRs). In this study, using the FSH receptor (FSH-R) as a model receptor, we demonstrate that part of the translational regulations occurs by phosphorylation of the translation pre-initiation complex scaffold protein, eukaryotic initiation factor 4G (eIF4G), in HEK293 cells stably expressing the FSH-R. This phosphorylation event occurred when eIF4G was bound to the mRNA 5' cap, and probably involves mammalian target of rapamycin. This regulation might contribute to cap-dependent translation in response to FSH. The cap-binding protein eIF4E also had its phosphorylation level enhanced upon FSH stimulation. We also show that FSH-induced signaling not only led to cap-dependent translation but also to internal ribosome entry site (IRES)-dependent translation of some mRNA. These data add detailed information on the molecular bases underlying the regulation of selective mRNA translation by a GPCR, and a topological model recapitulating these mechanisms is proposed.

  2. Designing, Leading and Managing the Transition to the Common Core: A Strategy Guidebook for Leaders

    ERIC Educational Resources Information Center

    Brown, Brentt; Vargo, Merrill

    2014-01-01

    The Common Core provides districts an opportunity to renew their focus on teaching and learning. But it also poses a number of design and implementation challenges for school districts. The "Leadership and Design Cycles" described in this guidebook offers an evidenced-based and structured process for leaders to design and implement…

  3. Leading Change for the Implementation of Common Core State Standards in Rural School Districts

    ERIC Educational Resources Information Center

    Lopez, Paul; Wise, Donald

    2015-01-01

    Rural school districts across the nation, with their limited resources, face daunting challenges posed by the implementation of the Common Core State Standards. This article presents a recent study of 13 rural school districts in the Central Valley of California and how these districts are responding to those challenges. A total of 352 teachers…

  4. Leading the Common Core State Standards: From Common Sense to Common Practice

    ERIC Educational Resources Information Center

    Dunkle, Cheryl A.

    2012-01-01

    Many educators agree that we already know how to foster student success, so what is keeping common sense from becoming common practice? The author provides step-by-step guidance for overcoming the barriers to adopting the Common Core State Standards (CCSS) and achieving equity and excellence for all students. As an experienced teacher and…

  5. A simple and facile synthesis of MPA capped CdSe and CdSe/CdS core/shell nanoparticles

    SciTech Connect

    Sukanya, D.; Sagayaraj, P.

    2015-06-24

    II-VI semiconductor nanostructures, in particular, CdSe quantum dots have drawn a lot of attention because of their promising potential applications in biological tagging, photovoltaic, display devices etc. due to their excellent optical properties, high emission quantum yield, size dependent emission wavelength and high photostability. In this paper, we describe the synthesis and properties of mercaptopropionic acid capped CdSe and CdSe/CdS nanoparticles through a simple and efficient co-precipitation method followed by hydrothermal treatment. The growth process, characterization and the optical absorption as a function of wavelength for the synthesized MPA capped CdSe and CdSe/CdS nanoparticles have been determined using X-ray diffraction study (XRD), Ultraviolet-Visible spectroscopy (UV-Vis), Fourier transform infrared spectroscopy (FT-IR) and High Resolution Transmission Electron Microscopy (HRTEM)

  6. High-throughput and virtual screening: core lead discovery technologies move towards integration.

    PubMed

    Good, A C.; Krystek, S R.; Mason, J S.

    2000-12-01

    In addition to high-throughput screening (HTS), the main lead discovery technology employed by most pharmaceutical companies today is virtual screening (VS). Although the two techniques have somewhat different philosophical origins, they contain many synergies that can potentially enhance the lead discovery process. Here, we describe many of the latest developments in VS technology with particular emphasis on their potential impact on HTS in, for example, focussed screening and data mining. In addition, we highlight key issues that need to be addressed before the potential of such efforts can be fully realized.

  7. Macromolecular Systems with MSA-Capped CdTe and CdTe/ZnS Core/Shell Quantum Dots as Superselective and Ultrasensitive Optical Sensors for Picric Acid Explosive.

    PubMed

    Dutta, Priyanka; Saikia, Dilip; Adhikary, Nirab Chandra; Sarma, Neelotpal Sen

    2015-11-11

    This work reports the development of highly fluorescent materials for the selective and efficient detection of picric acid explosive in the nanomolar range by fluorescence quenching phenomenon. Poly(vinyl alcohol) grafted polyaniline (PPA) and its nanocomposites with 2-mercaptosuccinic acid (MSA)-capped CdTe quantum dots (PPA-Q) and with MSA-capped CdTe/ZnS core/shell quantum dots (PPA-CSQ) are synthesized in a single step free radical polymerization reaction. The thermal stability and photo stability of the polymer increases in the order of PPA < PPA-Q < PPA-CSQ. The polymers show remarkably high selectivity and efficient sensitivity toward picric acid, and the quenching efficiency for PPA-CSQ reaches up to 99%. The detection limits of PPA, PPA-Q, and PPA-CSQ for picric acid are found to be 23, 1.6, and 0.65 nM, respectively, which are remarkably low. The mechanism operating in the quenching phenomenon is proposed to be a combination of a strong inner filter effect and ground state electrostatic interaction between the polymers and picric acid. A portable and cost-effective electronic device for the visual detection of picric acid by the sensory system is successfully fabricated. The device is further employed for quantitative detection of picric acid in real water samples. PMID:26484725

  8. Lead isotope ratios in six lake sediment cores from Japan Archipelago: Historical record of trans-boundary pollution sources.

    PubMed

    Hosono, Takahiro; Alvarez, Kelly; Kuwae, Michinobu

    2016-07-15

    Sediment cores from six lakes situated from north to south on the Japanese Archipelago were collected during 2009-2010 to investigate the hypothesis that deposition of lead (Pb) was coming from East Asia (including China, South Korea and eastern part of Russia). Accumulation rates and ages of the lake sediment were estimated by the (210)Pb constant rate of supply model and (137)Cs inputs to reconstruct the historical trends of Pb accumulation. Cores from four lakes located in the north and central Japan, showed clear evidence of Pb pollution with a change in the (206)Pb/(207)Pb and (208)Pb/(207)Pb ratios in the recent sediment as compared to the deeper sediment. Among the six studied lakes, significant inputs of anthropogenic lead emissions were observed at Lake Mikazuki (north Hokkaido in north Japan), Lake Chokai (north of Honshu), and Lake Mikuriga (central part of Honshu). Pb isotopic comparison of collected core sediment and previously reported data for wet precipitation and aerosols from different Asian regions indicate that, before 1900, Pb accumulated in these three lakes was not affected by trans-boundary sources. Lake Mikazuki started to receive Pb emissions from Russia in early 1900s, and during the last two decades, this lake has been affected by trans-boundary Pb pollution from northern China. Lake Chokai has received Pb pollutant from northern China since early 1900s until 2009, whereas for the Lake Mikuriga the major Pb contaminant was transported from southern China during the past 100years. The results of our study demonstrate that Japan Archipelago has received trans-boundary Pb emissions from different parts of East Asian region depending on location, and the major source region has changed historically. PMID:27058126

  9. First steps toward development of a stable isotope forward model for tropical ice cores: cold air incursions and snow days at Quelccaya Ice Cap, Peru

    NASA Astrophysics Data System (ADS)

    Hurley, J. V.; Vuille, M. F.; Hardy, D. R.; Burns, S. J.

    2014-12-01

    We are working towards a forward-model reconstruction of the South American Summer Monsoon (SASM) for the last millennium from the Quelccaya Ice Cap (QIC) d18O record. QIC receives precipitation almost exclusively during the SASM season. Initial efforts focus on dynamics that yield precipitation at this receding tropical ice cap, and how they relate to the hydrogen and oxygen stable isotopes. We present over a decade of daily snow-height change observations from the summit of QIC. Accumulation of snow (~2 m yr-1) at the summit occurs October through April, peaking in December. Net monthly snow-height change is negative May through September, though positive snow height change days do occur throughout the year. Snow height change time-series are used to develop d18O age-models for annual snow collected in vertical profiles near the summit of QIC since 2003. Snow d18O decreases during austral summer from about -17 to -24 per mil VSMOW. Post-depositional alteration of late summer snow during austral winter elevates d18O from about -24 to about -15 per mil VSMOW. Timing of 90thpercentile positive snow-height change events at QIC corresponds with regional precipitation and outgoing longwave radiation (OLR) anomalies that are dynamically triggered by cold air incursions propagating from the midlatitudes east of the Andes into the Amazon Basin. Precipitation and OLR anomalies migrate northwest in about 2-3 days from near Rio de la Plata to central Peru. The convective anomalies are the result of southerly horizontal wind anomalies in the lower troposphere that advect cold extratropical air equatorward. Composite analysis of satellite measurements shows that cold air incursions are associated with negative water vapor dD (~ -40 per mil) anomalies at QIC. We expect that snow stable isotope values from QIC are thus not only records of the deep overturning component of the monsoon circulation but also of synoptic scale monsoon disturbances. Cold air incursions into the South

  10. Reduced Biosynthesis of Digalactosyldiacylglycerol, a Major Chloroplast Membrane Lipid, Leads to Oxylipin Overproduction and Phloem Cap Lignification in Arabidopsis[OPEN

    PubMed Central

    Chen, Lih-Jen; Herrfurth, Cornelia

    2016-01-01

    DIGALACTOSYLDIACYLGLYCEROL SYNTHASE1 (DGD1) is a chloroplast outer membrane protein responsible for the biosynthesis of the lipid digalactosyldiacylglycerol (DGDG) from monogalactosyldiacylglycerol (MGDG). The Arabidopsis thaliana dgd1 mutants have a greater than 90% reduction in DGDG content, reduced photosynthesis, and altered chloroplast morphology. However, the most pronounced visible phenotype is the extremely short inflorescence stem, but how deficient DGDG biosynthesis causes this phenotype is unclear. We found that, in dgd1 mutants, phloem cap cells were lignified and jasmonic acid (JA)-responsive genes were highly upregulated under normal growth conditions. The coronative insensitive1 dgd1 and allene oxide synthase dgd1 double mutants no longer exhibited the short inflorescence stem and lignification phenotypes but still had the same lipid profile and reduced photosynthesis as dgd1 single mutants. Hormone and lipidomics analyses showed higher levels of JA, JA-isoleucine, 12-oxo-phytodienoic acid, and arabidopsides in dgd1 mutants. Transcript and protein level analyses further suggest that JA biosynthesis in dgd1 is initially activated through the increased expression of genes encoding 13-lipoxygenases (LOXs) and phospholipase A-Iγ3 (At1g51440), a plastid lipase with a high substrate preference for MGDG, and is sustained by further increases in LOX and allene oxide cyclase mRNA and protein levels. Our results demonstrate a link between the biosynthesis of DGDG and JA. PMID:26721860

  11. Leading Common Core Implementation

    ERIC Educational Resources Information Center

    Holliday, Terry; Smith, Felicia C.

    2012-01-01

    Kentucky is no stranger to education reform, having worked for the better part of 20 years on raising standards to improve student achievement. In 2009, the Kentucky General Assembly called for more rigorous standards to address high school graduates' college and career readiness. So when the National Governors Association and the Council of Chief…

  12. Historical lead isotope record of a sediment core from the Derwent River (Tasmania, Australia): a multiple source environment.

    PubMed

    Townsend, Ashley T; Seen, Andrew J

    2012-05-01

    A 105 cm sediment core from the Derwent River (Tasmania, Australia) was collected in 2004 and was characterised considering both physical (loss on ignition at 550 °C and grain size) and chemical (Fe, Cu, Zn, Cd and Pb concentrations, Pb isotope ratios and (210)Pb dating) properties. The core was analysed to (i) investigate the historical profiles of some important elements associated with the Risdon zinc refinery adjacent to the Derwent River, (ii) determine Pb isotopic signatures of sediment samples, and (iii) assess the veracity of Pb isotope ratios as indicators of contaminant Pb input. Extractable metal concentrations were (all values as mgkg(-1), non-normalised for grain size) Fe: 20,000-35,000, Zn: 42-4500, Pb: 5-1090, Cu: 13-141, and Cd: 1-31; with a close correlation between Cu, Zn, Cd and Pb. Metal enrichment factors (normalised to Al) were Pb: 0.9-144, Zn: 0.8-93, Cd: 0.8-30, Cu: 0.8-8.9 and Fe: 0.9-1.3, confirming anthropogenic contributions of Cu, Zn, Pb and Cd to the sediments. The onset of metal contamination above background levels occurred at a depth between 43 and 49 cm, with maximum concentrations noted near 20 cm for Cu, Zn, Cd and Pb. Lead isotope ratios were determined in sediments using sector field ICP-MS, and were found to be 36.5-38.8, 16.5-18.7 and 1.07-1.20 for (208)Pb/(204)Pb, (206)Pb/(204)Pb and (206)Pb/(207)Pb ratios, respectively. Major Australian ores processed at the refinery over the previous ~90 years include those from Broken Hill, Rosebery, Mt Isa, Elura, Hellyer and Century deposits. Anthropogenic impact by Pb with Broken Hill type isotopic ratio was initially evident in the core at 43-49 cm. The introduction of Rosebery and Elura ores to the refinery was also clearly noted. Pb isotope ratios further highlight that the Derwent River has been exposed to a greater impact by anthropogenic Pb in comparison to other major Tasmanian rivers, namely the Huon and Tamar.

  13. Historical and Future Black Carbon Deposition on the Three Ice Caps: Ice Core Measurements and Model Simulations from 1850 to 2100

    NASA Technical Reports Server (NTRS)

    Bauer, Susanne E.; Bausch, Alexandra; Nazarenko, Larissa; Tsigaridis, Kostas; Xu, Baiqing; Edwards. Ross; Bisiaux, Marion; McConnell, Joe

    2013-01-01

    Ice core measurements in conjunction with climate model simulations are of tremendous value when examining anthropogenic and natural aerosol loads and their role in past and future climates. Refractory black carbon (BC) records from the Arctic, the Antarctic, and the Himalayas are analyzed using three transient climate simulations performed with the Goddard Institute for Space Studies ModelE. Simulations differ in aerosol schemes (bulk aerosols vs. aerosol microphysics) and ocean couplings (fully coupled vs. prescribed ocean). Regional analyses for past (1850-2005) and future (2005-2100) carbonaceous aerosol simulations focus on the Antarctic, Greenland, and the Himalayas. Measurements from locations in the Antarctic show clean conditions with no detectable trend over the past 150 years. Historical atmospheric deposition of BC and sulfur in Greenland shows strong trends and is primarily influenced by emissions from early twentieth century agricultural and domestic practices. Models fail to reproduce observations of a sharp eightfold BC increase in Greenland at the beginning of the twentieth century that could be due to the only threefold increase in the North American emission inventory. BC deposition in Greenland is about 10 times greater than in Antarctica and 10 times less than in Tibet. The Himalayas show the most complicated transport patterns, due to the complex terrain and dynamical regimes of this region. Projections of future climate based on the four CMIP5 Representative Concentration Pathways indicate further dramatic advances of pollution to the Tibetan Plateau along with decreasing BC deposition fluxes in Greenland and the Antarctic.

  14. Probability modeling of the number of positive cores in a prostate cancer biopsy session, with applications.

    PubMed

    Serfling, Robert; Ogola, Gerald

    2016-02-10

    Among men, prostate cancer (CaP) is the most common newly diagnosed cancer and the second leading cause of death from cancer. A major issue of very large scale is avoiding both over-treatment and under-treatment of CaP cases. The central challenge is deciding clinical significance or insignificance when the CaP biopsy results are positive but only marginally so. A related concern is deciding how to increase the number of biopsy cores for larger prostates. As a foundation for improved choice of number of cores and improved interpretation of biopsy results, we develop a probability model for the number of positive cores found in a biopsy, given the total number of cores, the volumes of the tumor nodules, and - very importantly - the prostate volume. Also, three applications are carried out: guidelines for the number of cores as a function of prostate volume, decision rules for insignificant versus significant CaP using number of positive cores, and, using prior distributions on total tumor size, Bayesian posterior probabilities for insignificant CaP and posterior median CaP. The model-based results have generality of application, take prostate volume into account, and provide attractive tradeoffs of specificity versus sensitivity. Copyright © 2015 John Wiley & Sons, Ltd.

  15. Development of an unbonded capping system for clay masonry prisms

    SciTech Connect

    Crouch, L.K.; Henderson, R.C.; Sneed, W.A. Jr.

    1999-07-01

    To ascertain if an unbonded capping system was feasible for clay masonry prisms, the compressive strengths of thirty clay masonry prisms capped with an unbonded capping system modeled after ASTM C 1231 were compared with those of thirty masonry prisms capped with ASTM C 67 approved high-strength gypsum cement at the ages of 7 and 28 days. All prisms were constructed by a professional mason using Grade SW, Type FBS cored face brick from the same lot and ASTM C 270 Type S PC-lime mortar. There was no significant difference in mean compressive strength for the two capping methods at either age. In addition, capping with the unbonded capping system was faster and easier. Further, 28-day results obtained using the unbonded capping system had a lower coefficient of variation and higher mean compressive strength than those obtained with high-strength gypsum.

  16. Lead and sulfur isotopes of Guarn Halfaya and Bou Grine deposits associated to salt dome cap rocks (Diapirs zone, Northern Tunisia): sources of metals and genetic model

    NASA Astrophysics Data System (ADS)

    Jemmali, N.; Souissi, F.; Carranza, E. J. M.; Vennemann, T. W.

    2012-04-01

    The Pb-Zn ores districts at Guarn Halfaya and Bou Grine are hosted mainly by the dolostones in the contact breccias between Triassic and Upper Cretaceous and by Upper Cretaceous limestones. The mineralization occurs as lenticular, impregnations, substitutions, replacements, stratiform, vein, dissemination, and stockwork. A complex polymetallic sulfide assemblage typifies the main ore stage, dominated by sphalerite and galena, pyrite with minor chalcopyrite, arsenopyrite, and sulfosalt (grey copper). Limestone, barite and celestite dominate the gangue, with lesser calcite. Barite and celestite intergrown with main ore-stage sulfides of Oum Edeboua has δ34S values of 12.7 to 15.0 ‰, consistent with the derivation of sulfate from Triassic evaporites form the study area (12.8<δ34S<14.0 ‰). The δ34S values for sulfides of the both study area range from 2.6 to 9.5 ‰. These positive δ34S values are likely due to abiotic thermally-driven abiotic sulfate reduction (TSR) of Triassic sulfates at depth. However, the presence of bacterial relics suggests involvement of bacterially-mediated sulfate reduction (BSR). The lead isotope composition is homogeneous with 206Pb/204Pb, 207Pb/204Pb, and 208Pb/204Pb ratio ranging between from 18.723 to 18.783, 15.667 to 15.685, and 38.806 to 38.889, respectively, and plot between the upper crust and orogene curves of Zartman and Doe (1981) which imply involvement of a well-mixed multi-source reservoir of Pb at depth. The syn-diagenetic mineralization in the Bahloul Formation and the calculate of model age suggest a Late Cretaceous age, correspond to a NE-SW to ENE-WSS regional extensional tectonic events, which likely favored migration of mineralizing fluids and eventual deposition at Guarn Halfaya and Bou Grine.

  17. Using lead isotopes and trace element records from two contrasting Lake Tanganyika sediment cores to assess watershed – Lake exchange

    USGS Publications Warehouse

    Odigie, Kingsley; Cohen, A.D.; Swarzenski, Peter W.; Flegal, R

    2014-01-01

    Lead isotopic and trace element records of two contrasting sediment cores were examined to reconstruct historic, industrial contaminant inputs to Lake Tanganyika, Africa. Observed fluxes of Co, Cu, Mn, Ni, Pb, and Zn in age-dated sediments collected from the lake varied both spatially and temporally over the past two to four centuries. The fluxes of trace elements were lower (up to 10-fold) at a mid-lake site (MC1) than at a nearshore site (LT-98-58), which is directly downstream from the Kahama and Nyasanga River watersheds and adjacent to the relatively pristine Gombe Stream National Park. Trace element fluxes at that nearshore site did not measurably change over the last two centuries (1815–1998), while the distal, mid-lake site exhibited substantial changes in the fluxes of trace elements – likely caused by changes in land use – over that period. For example, the flux of Pb increased by ∼300% from 1871 to 1991. That apparent accelerated weathering and detrital mobilization of lithogenic trace elements was further evidenced by (i) positive correlations (r = 0.77–0.99, p < 0.05) between the fluxes of Co, Cu, Mn, Ni, Pb, and Zn and those of iron (Fe) at both sites, (ii) positive correlations (r = 0.82–0.98, p < 0.01, n = 9) between the fluxes of elements (Al, Co, Cu, Fe, Mn, Ni, Pb, and Zn) and the mass accumulation rates at the offshore site, (iii) the low enrichment factors (EF < 5) of those trace elements, and (iv) the temporal consistencies of the isotopic composition of Pb in the sediment. These measurements indicate that accelerated weathering, rather than industrialization, accounts for most of the increases in trace element fluxes to Lake Tanganyika in spite of the development of mining and smelting operations within the lake’s watershed over the past century. The data also indicate that the mid-lake site is a much more sensitive and useful recorder of environmental changes than the nearshore site. Furthermore, the lead isotopic compositions

  18. A hypothesis for vulnerable plaque rupture due to stress-induced debonding around cellular microcalcifications in thin fibrous caps

    PubMed Central

    Vengrenyuk, Yuliya; Carlier, Stéphane; Xanthos, Savvas; Cardoso, Luis; Ganatos, Peter; Virmani, Renu; Einav, Shmuel; Gilchrist, Lane; Weinbaum, Sheldon

    2006-01-01

    In this article, we advance a hypothesis for the rupture of thin fibrous cap atheroma, namely that minute (10-μm-diameter) cellular-level microcalcifications in the cap, which heretofore have gone undetected because they lie below the visibility of current in vivo imaging techniques, cause local stress concentrations that lead to interfacial debonding. New theoretical solutions are presented for the local stress concentration around these minute spherical inclusions that predict a nearly 2-fold increase in interfacial stress that is relatively insensitive to the location of the hypothesized microinclusions in the cap. To experimentally confirm the existence of the hypothesized cellular-level microcalcifications, we examined autopsy specimens of coronary atheromatous lesions using in vitro imaging techniques whose resolution far exceeds conventional magnetic resonance imaging, intravascular ultrasound, and optical coherence tomography approaches. These high-resolution imaging modalities, which include confocal microscopy with calcium-specific staining and micro-computed tomography imaging, provide images of cellular-level calcifications within the cap proper. As anticipated, the minute inclusions in the cap are very rare compared with the numerous calcified macrophages observed in the necrotic core. Our mathematical model predicts that inclusions located in an area of high circumferential stress (>300 kPa) in the cap can intensify this stress to nearly 600 kPa when the cap thickness is <65 μm. The most likely candidates for the inclusions are either calcified macrophages or smooth muscle cells that have undergone apoptosis. PMID:17003118

  19. Vinyl capped addition polyimides

    NASA Technical Reports Server (NTRS)

    Vannucci, Raymond D. (Inventor); Malarik, Diane C. (Inventor); Delvigs, Peter (Inventor)

    1991-01-01

    Polyimide resins (PMR) are generally useful where high strength and temperature capabilities are required (at temperatures up to about 700 F). Polyimide resins are particularly useful in applications such as jet engine compressor components, for example, blades, vanes, air seals, air splitters, and engine casing parts. Aromatic vinyl capped addition polyimides are obtained by reacting a diamine, an ester of tetracarboxylic acid, and an aromatic vinyl compound. Low void materials with improved oxidative stability when exposed to 700 F air may be fabricated as fiber reinforced high molecular weight capped polyimide composites. The aromatic vinyl capped polyimides are provided with a more aromatic nature and are more thermally stable than highly aliphatic, norbornenyl-type end-capped polyimides employed in PMR resins. The substitution of aromatic vinyl end-caps for norbornenyl end-caps in addition polyimides results in polymers with improved oxidative stability.

  20. Co-incubation with core proteins of HBV and HCV leads to modulation of human dendritic cells.

    PubMed

    Agrawal, Amogh; Samrat, Subodh K; Agrawal, Babita; Tyrrell, D Lorne J; Kumar, Rakesh

    2014-10-01

    Hepatitis B and C (HBV and HCV) are hepatotropic viruses in humans with approximately 350 and 170 million chronic carriers respectively. Since both viruses have similar modes of transmission, many people are co-infected. Co-infection is common in intravenous drug users, HIV-positive individuals, and transplant recipients. Compared to mono-infected patients, co-infected patients exhibit exacerbated liver cirrhosis, hepatocellular carcinoma, and liver failure. Some of the pathogenic effects may be attributed in part to the structural core proteins of both viruses-ones that have displayed immunomodulatory properties. Yet, the effects of their combined interaction on the human immune system remain a mystery. We aimed to elucidate the combined effects of HBV and HCV core proteins on human dendritic cells' (DCs) ability to present antigens and stimulate antigen-specific T-cells. We observed that when DCs, differentiated from human peripheral blood monocytes, were co-incubated with both core proteins, IL-10 production was dramatically enhanced, IL-6, TNF-α, and IL-12 production was significantly reduced, and HLA-DR expression was downregulated. This instant functional and phenotypic modulation of DCs induced by a combination of HBV and HCV core proteins can allow them to behave like tolerizing DCs, inefficiently presenting antigens to CD4+ T-cells and even suppressing induction of the cellular immune response. These results reveal an important mechanism by which HBV and HCV synergistically induce immune tolerance early in infection that may be instrumental in establishing chronic, persistent infections.

  1. Kinetics Parameters of VVER-1000 Core with 3 MOX Lead Test Assemblies To Be Used for Accident Analysis Codes

    SciTech Connect

    Pavlovitchev, A.M.

    2000-03-08

    The present work is a part of Joint U.S./Russian Project with Weapons-Grade Plutonium Disposition in VVER Reactor and presents the neutronics calculations of kinetics parameters of VVER-1000 core with 3 introduced MOX LTAs. MOX LTA design has been studied in [1] for two options of MOX LTA: 100% plutonium and of ''island'' type. As a result, zoning i.e. fissile plutonium enrichments in different plutonium zones, has been defined. VVER-1000 core with 3 introduced MOX LTAs of chosen design has been calculated in [2]. In present work, the neutronics data for transient analysis codes (RELAP [3]) has been obtained using the codes chain of RRC ''Kurchatov Institute'' [5] that is to be used for exploitation neutronics calculations of VVER. Nowadays the 3D assembly-by-assembly code BIPR-7A and 2D pin-by-pin code PERMAK-A, both with the neutronics constants prepared by the cell code TVS-M, are the base elements of this chain. It should be reminded that in [6] TVS-M was used only for the constants calculations of MOX FAs. In current calculations the code TVS-M has been used both for UOX and MOX fuel constants. Besides, the volume of presented information has been increased and additional explications have been included. The results for the reference uranium core [4] are presented in Chapter 2. The results for the core with 3 MOX LTAs are presented in Chapter 3. The conservatism that is connected with neutronics parameters and that must be taken into account during transient analysis calculations, is discussed in Chapter 4. The conservative parameters values are considered to be used in 1-point core kinetics models of accident analysis codes.

  2. Mars ice caps.

    PubMed

    Leovy, C

    1966-12-01

    Minimum atmospheric temperatures required to prevent CO(2) condensatio in the Mars polar caps are higher than those obtained in a computer experiment to simulate the general circulation of the Mars atmosphere. This observation supports the view that the polar caps are predominantly solid CO(2). However, thin clouds of H(2)0 ice could substantially reduce the surface condensation rate.

  3. Case Studies of Leading Edge Small Urban High Schools. Core Academic Strategic Designs: 3. University Park Campus School

    ERIC Educational Resources Information Center

    Shields, Regis Anne; Ireland, Nicole; City, Elizabeth; Derderian, Julie; Miles, Karen Hawley

    2008-01-01

    This report is one of nine detailed case studies of small urban high schools that served as the foundation for the Education Resource Strategies (ERS) report "Strategic Designs: Lessons from Leading Edge Small Urban High Schools." These nine schools were dubbed "Leading Edge Schools" because they stand apart from other high schools across the…

  4. Case Studies of Leading Edge Small Urban High Schools. Core Academic Strategic Designs: 1. Academy of the Pacific Rim

    ERIC Educational Resources Information Center

    Shields, Regis Anne; Ireland, Nicole; City, Elizabeth; Derderian, Julie; Miles, Karen Hawley

    2008-01-01

    This report is one of nine detailed case studies of small urban high schools that served as the foundation for the Education Resource Strategies (ERS) report "Strategic Designs: Lessons from Leading Edge Small Urban High Schools." These nine schools were dubbed "Leading Edge Schools" because they stand apart from other high schools across the…

  5. Case Studies of Leading Edge Small Urban High Schools. Core Academic Strategic Designs: 2. Noble Street Charter High School

    ERIC Educational Resources Information Center

    Shields, Regis Anne; Ireland, Nicole; City, Elizabeth; Derderian, Julie; Miles, Karen Hawley

    2008-01-01

    This report is one of nine detailed case studies of small urban high schools that served as the foundation for the Education Resource Strategies (ERS) report "Strategic Designs: Lessons from Leading Edge Small Urban High Schools." These nine schools were dubbed "Leading Edge Schools" because they stand apart from other high schools across the…

  6. Antarctic-wide array of high-resolution ice core records reveals pervasive lead pollution began in 1889 and persists today.

    PubMed

    McConnell, J R; Maselli, O J; Sigl, M; Vallelonga, P; Neumann, T; Anschütz, H; Bales, R C; Curran, M A J; Das, S B; Edwards, R; Kipfstuhl, S; Layman, L; Thomas, E R

    2014-07-28

    Interior Antarctica is among the most remote places on Earth and was thought to be beyond the reach of human impacts when Amundsen and Scott raced to the South Pole in 1911. Here we show detailed measurements from an extensive array of 16 ice cores quantifying substantial toxic heavy metal lead pollution at South Pole and throughout Antarctica by 1889 - beating polar explorers by more than 22 years. Unlike the Arctic where lead pollution peaked in the 1970s, lead pollution in Antarctica was as high in the early 20(th) century as at any time since industrialization. The similar timing and magnitude of changes in lead deposition across Antarctica, as well as the characteristic isotopic signature of Broken Hill lead found throughout the continent, suggest that this single emission source in southern Australia was responsible for the introduction of lead pollution into Antarctica at the end of the 19(th) century and remains a significant source today. An estimated 660 t of industrial lead have been deposited over Antarctica during the past 130 years as a result of mid-latitude industrial emissions, with regional-to-global scale circulation likely modulating aerosol concentrations. Despite abatement efforts, significant lead pollution in Antarctica persists into the 21(st) century.

  7. Antarctic-wide array of high-resolution ice core records reveals pervasive lead pollution began in 1889 and persists today.

    PubMed

    McConnell, J R; Maselli, O J; Sigl, M; Vallelonga, P; Neumann, T; Anschütz, H; Bales, R C; Curran, M A J; Das, S B; Edwards, R; Kipfstuhl, S; Layman, L; Thomas, E R

    2014-01-01

    Interior Antarctica is among the most remote places on Earth and was thought to be beyond the reach of human impacts when Amundsen and Scott raced to the South Pole in 1911. Here we show detailed measurements from an extensive array of 16 ice cores quantifying substantial toxic heavy metal lead pollution at South Pole and throughout Antarctica by 1889 - beating polar explorers by more than 22 years. Unlike the Arctic where lead pollution peaked in the 1970s, lead pollution in Antarctica was as high in the early 20(th) century as at any time since industrialization. The similar timing and magnitude of changes in lead deposition across Antarctica, as well as the characteristic isotopic signature of Broken Hill lead found throughout the continent, suggest that this single emission source in southern Australia was responsible for the introduction of lead pollution into Antarctica at the end of the 19(th) century and remains a significant source today. An estimated 660 t of industrial lead have been deposited over Antarctica during the past 130 years as a result of mid-latitude industrial emissions, with regional-to-global scale circulation likely modulating aerosol concentrations. Despite abatement efforts, significant lead pollution in Antarctica persists into the 21(st) century. PMID:25068819

  8. Antarctic-Wide Array of High-Resolution Ice Core Records Reveals Pervasive Lead Pollution Began in 1889 and Persists Today

    NASA Technical Reports Server (NTRS)

    McConnell, J. R.; Maselli, O. J.; Sigl, M.; Vallelonga, P.; Neumann, Thomas Allen; Anschutz, H.; Bales, R. C.; Curran, M. A. J.; Das, S. B.; Edwards, R.; Kipfstuhl, S.; Layman, L.; Thomas, E. R.

    2014-01-01

    Interior Antarctica is among the most remote places on Earth and was thought to be beyond the reach of human impacts when Amundsen and Scott raced to the South Pole in 1911. Here we show detailed measurements from an extensive array of 16 ice cores quantifying substantial toxic heavy metal lead pollution at South Pole and throughout Antarctica by 1889 - beating polar explorers by more than 22 years. Unlike the Arctic where lead pollution peaked in the 1970s, lead pollution in Antarctica was as high in the early 20th century as at any time since industrialization. The similar timing and magnitude of changes in lead deposition across Antarctica, as well as the characteristic isotopic signature of Broken Hill lead found throughout the continent, suggest that this single emission source in southern Australia was responsible for the introduction of lead pollution into Antarctica at the end of the 19th century and remains a significant source today. An estimated 660 t of industrial lead have been deposited over Antarctica during the past 130 years as a result of mid-latitude industrial emissions, with regional-to-global scale circulation likely modulating aerosol concentrations. Despite abatement efforts, significant lead pollution in Antarctica persists into the 21st century.

  9. Antarctic-wide array of high-resolution ice core records reveals pervasive lead pollution began in 1889 and persists today

    NASA Astrophysics Data System (ADS)

    McConnell, J. R.; Maselli, O. J.; Sigl, M.; Vallelonga, P.; Neumann, T.; Anschütz, H.; Bales, R. C.; Curran, M. A. J.; Das, S. B.; Edwards, R.; Kipfstuhl, S.; Layman, L.; Thomas, E. R.

    2014-07-01

    Interior Antarctica is among the most remote places on Earth and was thought to be beyond the reach of human impacts when Amundsen and Scott raced to the South Pole in 1911. Here we show detailed measurements from an extensive array of 16 ice cores quantifying substantial toxic heavy metal lead pollution at South Pole and throughout Antarctica by 1889 - beating polar explorers by more than 22 years. Unlike the Arctic where lead pollution peaked in the 1970s, lead pollution in Antarctica was as high in the early 20th century as at any time since industrialization. The similar timing and magnitude of changes in lead deposition across Antarctica, as well as the characteristic isotopic signature of Broken Hill lead found throughout the continent, suggest that this single emission source in southern Australia was responsible for the introduction of lead pollution into Antarctica at the end of the 19th century and remains a significant source today. An estimated 660 t of industrial lead have been deposited over Antarctica during the past 130 years as a result of mid-latitude industrial emissions, with regional-to-global scale circulation likely modulating aerosol concentrations. Despite abatement efforts, significant lead pollution in Antarctica persists into the 21st century.

  10. Lead users’ ideas on core features to support physical activity in rheumatoid arthritis: a first step in the development of an internet service using participatory design

    PubMed Central

    2014-01-01

    Background Despite the growing evidence of the benefits of physical activity (PA) in individuals with rheumatoid arthritis (RA), the majority is not physically active enough. An innovative strategy is to engage lead users in the development of PA interventions provided over the internet. The aim was to explore lead users’ ideas and prioritization of core features in a future internet service targeting adoption and maintenance of healthy PA in people with RA. Methods Six focus group interviews were performed with a purposively selected sample of 26 individuals with RA. Data were analyzed with qualitative content analysis and quantification of participants’ prioritization of most important content. Results Six categories were identified as core features for a future internet service: up-to-date and evidence-based information and instructions, self-regulation tools, social interaction, personalized set-up, attractive design and content, and access to the internet service. The categories represented four themes, or core aspects, important to consider in the design of the future service: (1) content, (2) customized options, (3) user interface and (4) access and implementation. Conclusions This is, to the best of our knowledge, the first study involving people with RA in the development of an internet service to support the adoption and maintenance of PA. Participants helped identifying core features and aspects important to consider and further explore during the next phase of development. We hypothesize that involvement of lead users will make transfer from theory to service more adequate and user-friendly and therefore will be an effective mean to facilitate PA behavior change. PMID:24655757

  11. Synthesis of a des-B-Ring Bryostatin Analogue Leads to an Unexpected Ring Expansion of the Bryolactone Core

    PubMed Central

    2015-01-01

    A convergent synthesis of a des-B-ring bryostatin analogue is described. This analogue was found to undergo an unexpected ring expansion of the bryolactone core to generate the corresponding 21-membered macrocycle. The parent analogue and the ring-expanded product both displayed nanomolar binding affinity for PKC. Despite containing A-ring substitution identical to that of bryostatin 1 and displaying bryostatin-like biological function, the des-B-ring analogues displayed a phorbol-like biological function in cells. These studies shed new light on the role of the bryostatin B-ring in conferring bryo-like biological function to bryostatin analogues. PMID:25207434

  12. Synthesis of a des-B-ring bryostatin analogue leads to an unexpected ring expansion of the bryolactone core.

    PubMed

    Kraft, Matthew B; Poudel, Yam B; Kedei, Noemi; Lewin, Nancy E; Peach, Megan L; Blumberg, Peter M; Keck, Gary E

    2014-09-24

    A convergent synthesis of a des-B-ring bryostatin analogue is described. This analogue was found to undergo an unexpected ring expansion of the bryolactone core to generate the corresponding 21-membered macrocycle. The parent analogue and the ring-expanded product both displayed nanomolar binding affinity for PKC. Despite containing A-ring substitution identical to that of bryostatin 1 and displaying bryostatin-like biological function, the des-B-ring analogues displayed a phorbol-like biological function in cells. These studies shed new light on the role of the bryostatin B-ring in conferring bryo-like biological function to bryostatin analogues.

  13. Synthesis of a des-B-ring bryostatin analogue leads to an unexpected ring expansion of the bryolactone core.

    PubMed

    Kraft, Matthew B; Poudel, Yam B; Kedei, Noemi; Lewin, Nancy E; Peach, Megan L; Blumberg, Peter M; Keck, Gary E

    2014-09-24

    A convergent synthesis of a des-B-ring bryostatin analogue is described. This analogue was found to undergo an unexpected ring expansion of the bryolactone core to generate the corresponding 21-membered macrocycle. The parent analogue and the ring-expanded product both displayed nanomolar binding affinity for PKC. Despite containing A-ring substitution identical to that of bryostatin 1 and displaying bryostatin-like biological function, the des-B-ring analogues displayed a phorbol-like biological function in cells. These studies shed new light on the role of the bryostatin B-ring in conferring bryo-like biological function to bryostatin analogues. PMID:25207434

  14. Dioxygen Activation by a Macrocyclic Copper Complex Leads to a Cu2O2 Core with Unexpected Structure and Reactivity.

    PubMed

    Garcia-Bosch, Isaac; Cowley, Ryan E; Díaz, Daniel E; Siegler, Maxime A; Nam, Wonwoo; Solomon, Edward I; Karlin, Kenneth D

    2016-04-01

    We report the Cu(I)/O2 chemistry of complexes derived from the macrocylic ligands 14-TMC (1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane) and 12-TMC (1,4,7,10-tetramethyl-1,4,7,10-tetraazacyclododecane). While [(14-TMC)Cu(I)](+) is unreactive towards dioxygen, the smaller analog [(12-TMC)Cu(I)(CH3CN)](+) reacts with O2 to give a side-on bound peroxo-dicopper(II) species ((S)P), confirmed by spectroscopic and computational methods. Intriguingly, 12-TMC as a N4 donor ligand generates (S)P species, thus in contrast with the previous observation that such species are generated by N2 and N3 ligands. In addition, the reactivity of this macrocyclic side-on peroxo-dicopper(II) differs from typical (S)P species, because it reacts only with acid to release H2O2, in contrast with the classic reactivity of Cu2O2 cores. Kinetics and computations are consistent with a protonation mechanism whereby the TMC acts as a hemilabile ligand and shuttles H(+) to an isomerized peroxo core.

  15. CCiCap: Boeing

    NASA Video Gallery

    NASA announced today its plans to partner with The Boeing Company for the next phase of the agency's Commercial Crew Program (CCP). Called Commercial Crew integrated Capability (CCiCap), the initia...

  16. CENTRIFUGE END CAP

    DOEpatents

    Beams, J.W.; Snoddy, L.B.

    1960-08-01

    An end cap for ultra-gas centrifuges is designed to impart or remove angular momentum to or from the gas and to bring the entering gas to the temperature of the gas inside the centrifuge. The end cap is provided with slots or fins for adjusting the temperature and the angular momentum of the entering gas to the temperature and momentum of the gas in the centrifuge and is constructed to introduce both the inner and the peripheral stream into the centrifuge.

  17. ROTOR END CAP

    DOEpatents

    Rushing, F.C.

    1959-02-01

    An improved end cap is described for the cylindrical rotor or bowl of a high-speed centrifugal separator adapted to permit free and efficient continuous counter current flow of gas therethrough for isotope separation. The end cap design provides for securely mounting the same to the hollow central shaft and external wall of the centrifuge. Passageways are incorporated and so arranged as to provide for continuous counter current flow of the light and heavy portions of the gas fed to the centrifuge.

  18. Lead-Cooled Fast Reactor (LFR) Design: Safety, Neutronics, Thermal Hydraulics, Structural Mechanics, Fuel, Core, and Plant Design

    SciTech Connect

    Smith, C

    2010-02-22

    The idea of developing fast spectrum reactors with molten lead (or lead alloy) as a coolant is not a new one. Although initially considered in the West in the 1950s, such technology was not pursued to completion because of anticipated difficulties associated with the corrosive nature of these coolant materials. However, in the Soviet Union, such technology was actively pursued during the same time frame (1950s through the 1980s) for the specialized role of submarine propulsion. More recently, there has been a renewal of interest in the West for such technology, both for critical systems as well as for Accelerator Driven Subcritical (ADS) systems. Meanwhile, interest in the former Soviet Union, primarily Russia, has remained strong and has expanded well beyond the original limited mission of submarine propulsion. This section reviews the past and current status of LFR development.

  19. Photoactivable caps for reactive metal nanoparticles

    NASA Astrophysics Data System (ADS)

    Patel, Ashish

    The synthesis and stabilization of reactive metal nanoparticles is often challenging under normal atmospheric conditions. This problem can be alleviated by capping and passivation. Our lab has focused on forming polymer coatings on the surface of reactive metal nanoparticles. We discovered a convenient and effective route for stabilization of aluminum nanoparticles (Al NPs), which uses the nascent metal core as a polymerization initiator for various organic monomers. In our previous work, we used this method to passivate the Al NPs using variety of epoxides and copolymers of epoxides and alkenes. These products have demonstrated air stability for weeks to months with little to no degradation in the active Al content. Since our previously synthesized Al NP's were not beneficial for rapid and efficient thermodynamic access to the active Al core, our goal was find polymers that could easily be photochemically activated to enhance such access. Since poly(methyl methacrylate) (PMMA) has photodegrading properties, we used PMMA as a capping agent to passivate Al NPs. In this work, we present capping and stabilization of Al NPs with PMMA, and also with 1,2-epoxyhexane/ PMMA. In our previous work, we increased the stability of Al NP capped with 1,2-epoxy-9-decene by adding 1,13-tetradecadiene as a cross-linker. Here, we used the methyl methacrylate (MMA) monomer as cross-linker for Al NP capped with 1,2-epoxy-9-decene. We have also used the MMA as capping agent. We use powder x-ray diffractametry (PXRD), differential scanning calorimetry (DSC), and thermogravity analysis (TGA) to confirm the presence of elemental Al and ATR-FTIR to confirm the presence of polymers.

  20. Correlation of the neutron star crust-core properties with the slope of the symmetry energy and the lead skin thickness

    NASA Astrophysics Data System (ADS)

    Pais, H.; Sulaksono, A.; Agrawal, B. K.; Providência, C.

    2016-04-01

    The correlations of the crust-core transition density and pressure in neutron stars with the slope of the symmetry energy and the neutron skin thickness are investigated, using different families of relativistic mean-field parametrizations with constant couplings and nonlinear terms mixing the σ - , ω - , and ρ -meson fields. It is shown that the modification of the density dependence of the symmetry energy, involving the σ or the ω meson, gives rise to different behaviors: the effect of the ω meson may also be reproduced within nonrelativistic phenomenological models, while the effect of the σ meson is essentially relativistic. Depending on the parametrization with σ -ρ or ω -ρ mixing terms, different values of the slope of the symmetry energy at saturation must be considered in order to obtain a neutron matter equation of state compatible with results from chiral effective field theory. This difference leads to different pressures at the crust-core transition density. A linear correlation between the transition density and the symmetry energy slope or the neutron skin thickness of the 208Pb nucleus is obtained, only when the ω meson is used to describe the density dependence of the symmetry energy. A comparison is made between the crust-core transition properties of neutron stars obtained by three different methods, the relativistic random phase approximation (RRPA), the Vlasov equation, and thermodynamical method. It is shown that the RRPA and the Vlasov methods predict similar transition densities for p n e β -equilibrium stellar matter.

  1. Do Porins Pass CAPs?

    NASA Astrophysics Data System (ADS)

    Hanna, C. B.; Pink, D. A.; Gill, T. A.; Beveridge, T. J.; Quinn, B. E.; Durrant, J. J.; Jericho, M. H.

    2008-03-01

    The cationic antimicrobial peptide (CAP) protamine is known to inhibit bacterial survival (Pink et al., Langmuir 19, 8852 (2003), and references therein), but the mechanism of attack is as yet undetermined. For Gram-negative bacteria, two pathways have been proposed: (a) self-promoted uptake, and (b) passage through porins. Here, we study the latter possibility, and model part of the outer membrane of a Gram-negative bacterium in an aqueous solution containing multivalent ions and CAPs. The intent is to determine whether CAPs could pass through porins and, if so, what aspects of external (e.g., ionic concentration) and internal (e.g., porin and O-sidechain characteristics) parameters affect their passage. This study is accomplished via Monte Carlo computer simulations of a ``minimal model'' of the outer membrane of a Gram-negative bacterium with an embedded porin.

  2. Magnetospheric polar cap

    NASA Astrophysics Data System (ADS)

    Akasofu, S. I.; Kan, J. R.

    Mount Denali (McKinley), the Alaska Range, and countless glaciers welcomed all 86 participants of the Chapman Conference on the Magnetospheric Polar Cap, which was held on the University of Alaska, Fairbanks campus (UAF), on August 6-9, 1984. The magnetospheric polar cap is the highest latitude region of the earth which is surrounded by the ring of auroras (the auroral oval). This particular region of the earth has become a focus of magnetospheric physicists during the last several years. This is because a number of upper atmospheric phenomena in the polar cap are found to be crucial in understanding the solar wind—magnetosphere interaction. The conference was opened by J. G. Roederer, who was followed by the UAF Chancellor, P. J. O'Rourke, who officially welcomed the participants.

  3. North Polar Cap

    NASA Technical Reports Server (NTRS)

    2004-01-01

    7 September 2004 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a 1.4 m/pixel (5 ft/pixel) view of a typical martian north polar ice cap texture. The surface is pitted and rough at the scale of several meters. The north polar residual cap of Mars consists mainly of water ice, while the south polar residual cap is mostly carbon dioxide. This picture is located near 85.2oN, 283.2oW. The image covers an area approximately 1 km wide by 1.4 km high (0.62 by 0.87 miles). Sunlight illuminates this scene from the lower left.

  4. Commercialization Assistance Program (CAP)

    SciTech Connect

    Jenny C. Servo, Ph.D.

    2004-07-12

    In order to fulfill the objective of Small Business Innovation Research Program (SBIR), the Department of Energy funds an initiative referred to as the Commercialization Assistance Program (CAP). The over-arching purpose of the CAP is to facilitate transition of the SBIR-funded technology to Phase III defined as private sector investment or receipt of non-sbir dollars to further the commercialization of the technology. Phase III also includes increased sales. This report summarizes the stages involved in the implementation of the Commercialization Assistance Program, a program which has been most successful in fulfilling its objectives.

  5. Ice caps on venus?

    PubMed

    Libby, W F

    1968-03-01

    The data on Venus obtained by Mariner V and Venera 4 are interpreted as evidence of giant polar ice caps holding the water that must have come out of the volcanoes with the observed carbon dioxide, on the assumption that Earth and Venus are of similar composition and volcanic history. The measurements by Venera 4 of the equatorial surface temperature indicate that the microwave readings were high, so that the polar ice caps may be allowed to exist in the face of the 10-centimeter readings of polar temperature. Life seems to be distinctly possible at the edges of the ice sheets.

  6. South Polar Cap

    NASA Technical Reports Server (NTRS)

    2005-01-01

    8 December 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows landforms created by sublimation processes on the south polar residual cap of Mars. The bulk of the ice in the south polar residual cap is frozen carbon dioxide.

    Location near: 86.6oS, 342.2oW Image width: width: 3 km (1.9 mi) Illumination from: upper left Season: Southern Summer

  7. [Capping strategies in RNA viruses].

    PubMed

    Bouvet, Mickaël; Ferron, François; Imbert, Isabelle; Gluais, Laure; Selisko, Barbara; Coutard, Bruno; Canard, Bruno; Decroly, Etienne

    2012-04-01

    Most viruses use the mRNA-cap dependent cellular translation machinery to translate their mRNAs into proteins. The addition of a cap structure at the 5' end of mRNA is therefore an essential step for the replication of many virus families. Additionally, the cap protects the viral RNA from degradation by cellular nucleases and prevents viral RNA recognition by innate immunity mechanisms. Viral RNAs acquire their cap structure either by using cellular capping enzymes, by stealing the cap of cellular mRNA in a process named "cap snatching", or using virus-encoded capping enzymes. Many viral enzymes involved in this process have recently been structurally and functionally characterized. These studies have revealed original cap synthesis mechanisms and pave the way towards the development of specific inhibitors bearing antiviral drug potential. PMID:22549871

  8. The crystal structure of the PB2 cap-binding domain of influenza B virus reveals a novel cap recognition mechanism.

    PubMed

    Liu, Yong; Yang, Yongfeng; Fan, Jialin; He, Ruina; Luo, Ming; Zheng, Xiaofeng

    2015-04-01

    The influenza RNA-dependent RNA polymerase is a core enzyme required for both transcription and replication of the virus RNA genome, making it a potential drug target for the influenza virus. To detect the feature of cap-dependent transcription of influenza B virus (FluB) polymerase, we determined the crystal structures of the wild-type FluB polymerase PB2 subunit cap-binding domain (PB2cap) with bound GDP and the mutant FluB Q325F PB2cap with bound m(7)GDP or GDP. These structures revealed that, distinct from influenza A virus (FluA) PB2cap, the guanine and ribose moieties of substrates invert in FluB PB2caps. Moreover, we characterized the substrate specificity and affinity of the PB2caps using isothermal titration calorimetry. FluB PB2cap has a weaker affinity for m(7)GDP than FluA PB2cap. Unlike FluA PB2cap that has a preference for m(7)GDP in comparison with GDP, FluB PB2cap shows an analogous affinity for both substrates. Replacement of FluB PB2 Glu(325) by Phe, the corresponding residue of FluA PB2, increased the binding affinity of FluB PB2cap for m(7)GDP to a level approximate to that of FluA PB2cap and caused a significant higher affinity to GDP. This study indicated that FluB PB2cap has a unique cap recognition mechanism compared with FluA PB2cap, providing molecular insight into inhibitor design targeting FluB PB2cap.

  9. 3. CAP; CONICAL CAP HAS BOWED RAFTERS MORTISED INTO A ...

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

    3. CAP; CONICAL CAP HAS BOWED RAFTERS MORTISED INTO A BOSS; ALSO SEEN ARE THE BRAKE WHEEL, WINDSHAFT AND TOP BEARING OF THE UPRIGHT SHAFT - Hayground Windmill, Windmill Lane, East Hampton, Suffolk County, NY

  10. Advising. CAP Job Function.

    ERIC Educational Resources Information Center

    Ohio State Univ., Columbus. National Center for Research in Vocational Education.

    This Job Function Book (Advising) is one of the 14 components (see note) of the Career Alert Planning (CAP) program, a set of individualized materials designed to help participants find out about themselves and about the kind of work for which they are suited. In this program, participants become acquainted with occupations that are representative…

  11. Guard For Fuse Caps

    NASA Technical Reports Server (NTRS)

    Atwell, D. C.

    1985-01-01

    L-shaped guard attached to fuse holder. Guard prevents casual tampering with fuses in electrical junction box or fuse block. Protects fuses from being damaged by handling or by rope or string used to secure them. With fuse-cap guard, only responsible people have access to fuses.

  12. Arranging. CAP Job Function.

    ERIC Educational Resources Information Center

    Ohio State Univ., Columbus. National Center for Research in Vocational Education.

    This Job Function Booklet (Arranging) is one of the 14 components (see note) of the Career Alert Planning (CAP) program, a set of individualized materials designed to help participants find out about themselves and about the kind of work for which they are suited. In this program, participants become acquainted with occupations that are…

  13. Mechanical properties at high strain-rate of lead core and brass jacket of a NATO 7.62 mm ball bullet

    NASA Astrophysics Data System (ADS)

    Peroni, L.; Scapin, M.; Fichera, C.; Manes, A.; Giglio, M.

    2012-08-01

    Numerical simulations are now an actual option in order to try to reproduce and understand the mechanical response in components subjected to extreme loading conditions, like in a ballistic impact. A correct materials calibration is therefore necessary in order to extract the materials parameters. In this work the simple and widely used Johnson-Cook model was used to analyse the experimental data obtained for the characterization of the bullet materials. The bullet under investigation is a full metal jacket ball, with a lead-antimony alloy core and a brass jacket. The experimental tests cover a wide range in strain-rate, starting from quasi-static tests up to high dynamic tests performed on a standard Split Hopkinson Pressure Bar setup. In general, there is a great lack in strain-rate sensitivity and failure data. Pure lead is very soft and ductile, so antimony is used to give greater hardness and strength. The results of this study show a significant strain-rate influence for this alloy that can be associated with the presence of the lead-antimony phases and their structures. Also in case of the brass the results showed significant strain-rate sensitivity in the material response.

  14. Cap protects aircraft nose cone

    NASA Technical Reports Server (NTRS)

    Bryan, C. F., Jr.; Bryan, D. C.

    1981-01-01

    Inexpensive, easily fabricated cap protects aircraft nose cone from erosion. Made of molded polycarbonate, cap has been flight tested at both subsonic and supesonic speeds. Its strength and erosion characteristics are superior to those of fiberglass cones.

  15. Designing Smart Charter School Caps

    ERIC Educational Resources Information Center

    Dillon, Erin

    2010-01-01

    In 2007, Andrew J. Rotherham proposed a new approach to the contentious issue of charter school caps, the statutory limits on charter school growth in place in several states. Rotherham's proposal, termed "smart charter school caps," called for quality sensitive caps that allow the expansion of high-performing charter schools while also…

  16. The size of the EB cap determines instantaneous microtubule stability

    PubMed Central

    Duellberg, Christian; Cade, Nicholas I; Holmes, David; Surrey, Thomas

    2016-01-01

    The function of microtubules relies on their ability to switch between phases of growth and shrinkage. A nucleotide-dependent stabilising cap at microtubule ends is thought to be lost before this switch can occur; however, the nature and size of this protective cap are unknown. Using a microfluidics-assisted multi-colour TIRF microscopy assay with close-to-nm and sub-second precision, we measured the sizes of the stabilizing cap of individual microtubules. We find that the protective caps are formed by the extended binding regions of EB proteins. Cap lengths vary considerably and longer caps are more stable. Nevertheless, the trigger of instability lies in a short region at the end of the cap, as a quantitative model of cap stability demonstrates. Our study establishes the spatial and kinetic characteristics of the protective cap and provides an insight into the molecular mechanism by which its loss leads to the switch from microtubule growth to shrinkage. DOI: http://dx.doi.org/10.7554/eLife.13470.001 PMID:27050486

  17. Summer South Polar Cap

    NASA Technical Reports Server (NTRS)

    2004-01-01

    13 April 2004 The martian south polar residual ice cap is composed mainly of frozen carbon dioxide. Each summer, a little bit of this carbon dioxide sublimes away. Pits grow larger, and mesas get smaller, as this process continues from year to year. This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a view of a small portion of the south polar cap as it appeared in mid-summer in January 2004. The dark areas may be places where the frozen carbon dioxide contains impurities, such as dust, or places where sublimation of ice has roughened the surface so that it appears darker because of small shadows cast by irregularities in the roughened surface. The image is located near 86.9oS, 7.6oW. The image covers an area about 3 km (1.9 mi) across. Sunlight illuminates the scene from the upper left.

  18. Performance of blasting caps

    NASA Technical Reports Server (NTRS)

    Bement, Laurence J. (Inventor); Schimmel, Morry L. (Inventor); Perry, Ronnie B. (Inventor)

    1993-01-01

    Common blasting caps are made from an aluminum shell in the form of a tube which is closed at both ends. One end, which is called the output end, terminates in a principal side or face, and contains a detonating agent which communicates with a means for igniting the detonating agent. The improvement of the present invention is a flat, steel foil bonded to the face in a position which is aligned perpendicularly to the longitudinal axis of the tube.

  19. A Method for Computing the Core Flow in Three-Dimensional Leading-Edge Vortices. Ph.D. Thesis - North Carolina State Univ.

    NASA Technical Reports Server (NTRS)

    Luckring, J. M.

    1985-01-01

    A theory is presented for calculating the flow in the core of a separation-induced leading-edge vortex. The method is based on matching inner and outer representations of the vortex. The inner model of the vortex is based on the quasicylindrical Navier-Stokes equations; the flow is assumed to be steady, axially symmetric, and incompressible and in addition, gradients in the radial direction are assumed to be much larger then gradients in the axial direction. The outer model is based on the three-dimensional free-vortex-sheet theory, a higher-order panel method which solves the Prandtl-Glauert equation including nonlinear boundary conditions pertinent to the concentrated vorticity representation of the leading edge vortex. The resultant flow is evaluated a posteriori for evidence of incipient vortex breakdown and the critical helix angle concept, in conjunction with an adverse longitudinal pressure gradient, is found to correlate well with the occurrence of vortex breakdown at the trailing edge of delta, arrow, and diamond wings.

  20. North Polar Ice Cap

    NASA Technical Reports Server (NTRS)

    1997-01-01

    North polar ice cap of Mars, as seen during mid summer in the northern hemisphere. The reddish areas consist of eolian dust, bright white areas consist of a mixture of water ice and dust, and the dark blue areas consist of sand dunes forming a huge 'collar' around the polar ice cap. (The colors have been enhanced with a decorrelation stretch to better show the color variability.) Shown here is an oblique view of the polar region, as seen with the Viking 1 spacecraft orbiting Mars over latitude 39 degrees north. The spiral bands consist of valleys which form by a combination of the Coriolis forces, wind erosion, and differential sublimation and condensation. In high-resolution images the polar caps are seen to consist of thick sequences of layered deposits, suggesting that cyclical climate changes have occurred on Mars. Cyclical climate changes are readily explained by quasi-periodic changes in the amount and distribution of solar heating resulting from perturbations in orbital and axial elements. Variations in the Earth's orbit have also been linked to the terrestrial climate changes during the ice ages.

  1. Interaction of Ca(2+)-dependent activator protein for secretion 1 (CAPS1) with septin family proteins in mouse brain.

    PubMed

    Hosono, Mayu; Shinoda, Yo; Hirano, Touko; Ishizaki, Yasuki; Furuichi, Teiichi; Sadakata, Tetsushi

    2016-03-23

    The Ca(2+)-dependent activator protein for secretion 1 (CAPS1) protein plays a regulatory role in the dense-core vesicle exocytosis pathway. To clarify the functions of this protein in the brain, we searched for novel interaction partners of CAPS1 by mass spectrometry. We identified a specific interaction of CAPS1 with septin family proteins. We also demonstrated that the C-terminal region of the CAPS1 protein binds to part of the deduced GTP-binding domain of septin proteins. It is possible that a tertiary complex of septin, CAPS, and syntaxin contributes to dense-core vesicle trafficking and exocytosis in neurons.

  2. Saltstone Clean Cap Formulation

    SciTech Connect

    Langton, C

    2005-04-22

    The current operation strategy for using Saltstone Vault 4 to receive 0.2 Ci/gallon salt solution waste involves pouring a clean grout layer over the radioactive grout prior to initiating pour into another cell. This will minimize the radiating surface area and reduce the dose rate at the vault and surrounding area. The Clean Cap will be used to shield about four feet of Saltstone poured into a Z-Area vault cell prior to moving to another cell. The minimum thickness of the Clean Cap layer will be determined by the cesium concentration and resulting dose levels and it is expected to be about one foot thick based on current calculations for 0.1 Ci Saltstone that is produced in the Saltstone process by stabilization of 0.2 Ci salt solution. This report documents experiments performed to identify a formulation for the Clean Cap. Thermal transient calculations, adiabatic temperature rise measurements, pour height, time between pour calculations and shielding calculations were beyond the scope and time limitations of this study. However, data required for shielding calculations (composition and specific gravity) are provided for shielding calculations. The approach used to design a Clean Cap formulation was to produce a slurry from the reference premix (10/45/45 weight percent cement/slag/fly ash) and domestic water that resembled as closely as possible the properties of the Saltstone slurry. In addition, options were investigated that may offer advantages such as less bleed water and less heat generation. The options with less bleed water required addition of dispersants. The options with lower heat contained more fly ash and less slag. A mix containing 10/45/45 weight percent cement/slag/fly ash with a water to premix ratio of 0.60 is recommended for the Clean Cap. Although this mix may generate more than 3 volume percent standing water (bleed water), it has rheological, mixing and flow properties that are similar to previously processed Saltstone. The recommended

  3. Lack of parvalbumin in mice leads to behavioral deficits relevant to all human autism core symptoms and related neural morphofunctional abnormalities

    PubMed Central

    Wöhr, M; Orduz, D; Gregory, P; Moreno, H; Khan, U; Vörckel, K J; Wolfer, D P; Welzl, H; Gall, D; Schiffmann, S N; Schwaller, B

    2015-01-01

    Gene mutations and gene copy number variants are associated with autism spectrum disorders (ASDs). Affected gene products are often part of signaling networks implicated in synapse formation and/or function leading to alterations in the excitation/inhibition (E/I) balance. Although the network of parvalbumin (PV)-expressing interneurons has gained particular attention in ASD, little is known on PV's putative role with respect to ASD. Genetic mouse models represent powerful translational tools for studying the role of genetic and neurobiological factors underlying ASD. Here, we report that PV knockout mice (PV−/−) display behavioral phenotypes with relevance to all three core symptoms present in human ASD patients: abnormal reciprocal social interactions, impairments in communication and repetitive and stereotyped patterns of behavior. PV-depleted mice also showed several signs of ASD-associated comorbidities, such as reduced pain sensitivity and startle responses yet increased seizure susceptibility, whereas no evidence for behavioral phenotypes with relevance to anxiety, depression and schizophrenia was obtained. Reduced social interactions and communication were also observed in heterozygous (PV+/−) mice characterized by lower PV expression levels, indicating that merely a decrease in PV levels might be sufficient to elicit core ASD-like deficits. Structural magnetic resonance imaging measurements in PV−/− and PV+/− mice further revealed ASD-associated developmental neuroanatomical changes, including transient cortical hypertrophy and cerebellar hypoplasia. Electrophysiological experiments finally demonstrated that the E/I balance in these mice is altered by modification of both inhibitory and excitatory synaptic transmission. On the basis of the reported changes in PV expression patterns in several, mostly genetic rodent models of ASD, we propose that in these models downregulation of PV might represent one of the points of convergence, thus

  4. Environmental exposure to lead, but not other neurotoxic metals, relates to core elements of ADHD in Romanian children: performance and questionnaire data.

    PubMed

    Nicolescu, Rodica; Petcu, Cristian; Cordeanu, Aurelia; Fabritius, Klaus; Schlumpf, Margret; Krebs, Rolf; Krämer, Ursula; Winneke, Gerhard

    2010-07-01

    Neurobehavioral measures of attention, and clinical features of the attention-deficit hyperactivity disorder (ADHD) have been studied in pediatric environmental lead research. However rarely, if ever, have performance measures of attention or executive functions and questionnaire-based quantitative ADHD-observations been studied in the same subjects. We examined associations between pediatric blood lead concentrations (PbB), as well as those of mercury (Hg), and aluminum (Al), and performance in four different attention tasks, as well as behavioral ratings from an ICD-10 (hyperactivity) and DSM-IV-coded (attention deficit) German questionnaire (FBB-ADHS). Asymptomatic, 8-12 year old children from two Romanian cities were studied, namely Bucharest and Pantelimon, a city near a metal-processing plant. Blood was analyzed for Pb, Al, and Hg. Data from 83 children were available for final analysis. We assessed attention performance by means of four tasks of the computer-based ADHD-taylored German KITAP-battery. We also received questionnaire ratings from parents and teachers covering three ADHD-dimensions. Multiple linear regression analysis was used to estimate associations between the three neurotoxic trace metals in blood and the different ADHD features. After adjusting for eleven potentially confounding variables we found consistent borderline to significant associations between Pb, but not other metals, in blood and various performance- and questionnaire data. False alarm responses (FAR) in the KITAP subtests rather than response latencies exhibited positive associations with PbB. Questionnaire ratings for ADHD dimensions also revealed PbB-related adversity. With any two-fold increase of PbB outcome changed markedly, namely up to 35%. Restriction to children with PbBs<10mug/dl had only a marginal influence on outcome.The converging evidence from performance- and questionnaire data confirms that core elements of ADHD are adversely affected by low environmental Pb

  5. Environmental exposure to lead, but not other neurotoxic metals, relates to core elements of ADHD in Romanian children: performance and questionnaire data.

    PubMed

    Nicolescu, Rodica; Petcu, Cristian; Cordeanu, Aurelia; Fabritius, Klaus; Schlumpf, Margret; Krebs, Rolf; Krämer, Ursula; Winneke, Gerhard

    2010-07-01

    Neurobehavioral measures of attention, and clinical features of the attention-deficit hyperactivity disorder (ADHD) have been studied in pediatric environmental lead research. However rarely, if ever, have performance measures of attention or executive functions and questionnaire-based quantitative ADHD-observations been studied in the same subjects. We examined associations between pediatric blood lead concentrations (PbB), as well as those of mercury (Hg), and aluminum (Al), and performance in four different attention tasks, as well as behavioral ratings from an ICD-10 (hyperactivity) and DSM-IV-coded (attention deficit) German questionnaire (FBB-ADHS). Asymptomatic, 8-12 year old children from two Romanian cities were studied, namely Bucharest and Pantelimon, a city near a metal-processing plant. Blood was analyzed for Pb, Al, and Hg. Data from 83 children were available for final analysis. We assessed attention performance by means of four tasks of the computer-based ADHD-taylored German KITAP-battery. We also received questionnaire ratings from parents and teachers covering three ADHD-dimensions. Multiple linear regression analysis was used to estimate associations between the three neurotoxic trace metals in blood and the different ADHD features. After adjusting for eleven potentially confounding variables we found consistent borderline to significant associations between Pb, but not other metals, in blood and various performance- and questionnaire data. False alarm responses (FAR) in the KITAP subtests rather than response latencies exhibited positive associations with PbB. Questionnaire ratings for ADHD dimensions also revealed PbB-related adversity. With any two-fold increase of PbB outcome changed markedly, namely up to 35%. Restriction to children with PbBs<10mug/dl had only a marginal influence on outcome.The converging evidence from performance- and questionnaire data confirms that core elements of ADHD are adversely affected by low environmental Pb

  6. Vinyl capped addition polyimides

    NASA Technical Reports Server (NTRS)

    Vannucci, Raymond D. (Inventor); Malarik, Diane C. (Inventor); Delvigs, Peter (Inventor)

    1990-01-01

    Polyimide resins having improved thermo-oxidative stability are provided having aromatic vinyl end-caps. The polyimides are prepared by the reaction of a mixture of monomers comprising (1) a diamine, (2) an ester of tetracarboxylic acid and (3) an aromatic vinyl compound in a molar ratio of 1:2:3 of n: (n + 1):2 when the aromatic vinyl compound contains nitrogen and in a ratio of (n + 1):n:2 when the aromatic vinyl compound does not contain nitrogen, wherein n ranges from about 5 to about 20.

  7. Effect of swim cap model on passive drag.

    PubMed

    Gatta, Giorgio; Zamparo, Paola; Cortesi, Matteo

    2013-10-01

    Hydrodynamics plays an important role in swimming because even small decreases in a swimmer's drag can lead to performance improvements. During the gliding phases of a race, the head of a swimmer is an important point of impact with the fluid, and the swim cap, even if it covers only a small portion of the swimmer's body, can have an influence on drag. The purpose of this study was to investigate the effects on passive drag (Dp) of wearing 3 different types of swim caps (LSC: a lycra cap; CSC: a silicone cap; HSC: a silicone helmet cap without seams). Sixteen swimmers were tested at 3 velocities (1.5, 1.7, 1.9 m·s), and the Dp measurements were repeated at each condition 5 times. A statistical analysis revealed significant differences in drag (p < 0.01) among caps: Dp is 5-6.5% lower for HSC than for CSC at all speeds and 6% lower in HSC than CSC at 1.9 m·s. No differences in Dp were observed between LSC and CSC at all speeds. Thus, the differences in Dp are based on the type of material (lycra vs. silicone) and on the presence/lack of seams: the HSC swim cap is the most rigid, the most adherent to the swimmer's head, and does not allow the formation of wrinkles compared with the other 2 investigated swim caps. Therefore, the following conclusions can be made: (a) swimmers should take care when selecting their swim cap if they want to improve the fluid dynamics at the "leading edge" of their body and (b) because Dp is affected by the swim cap model, care should be taken when comparing data from different studies, especially at faster investigated speeds.

  8. Edge of polar cap patches

    NASA Astrophysics Data System (ADS)

    Hosokawa, K.; Taguchi, S.; Ogawa, Y.

    2016-04-01

    On the night of 4 December 2013, a sequence of polar cap patches was captured by an all-sky airglow imager (ASI) in Longyearbyen, Norway (78.1°N, 15.5°E). The 630.0 nm airglow images from the ASI of 4 second exposure time, oversampled the emission of natural lifetime (with quenching) of at least ˜30 sec, introduce no observational blurring effects. By using such high-quality ASI images, we succeeded in visualizing an asymmetry in the gradients between the leading/trailing edges of the patches in a 2-D fashion. The gradient in the leading edge was found to be 2-3 times steeper than that in the trailing edge. We also identified fingerlike structures, appearing only along the trailing edge of the patches, whose horizontal scale size ranged from 55 to 210 km. These fingers are considered to be manifestations of plasma structuring through the gradient-drift instability (GDI), which is known to occur only along the trailing edge of patches. That is, the current 2-D observations visualized, for the first time, how GDI stirs the patch plasma and such a mixing process makes the trailing edge more gradual. This result strongly implies a close connection between the GDI-driven plasma stirring and the asymmetry in the large-scale shape of patches and then suggests that the fingerlike structures can be used as markers to estimate the fine-scale structure in the plasma flow within patches.

  9. Polar Cap Pits

    NASA Technical Reports Server (NTRS)

    2005-01-01

    17 August 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows kidney bean-shaped pits, and other pits, formed by erosion in a landscape of frozen carbon dioxide. This images shows one of about a dozen different patterns that are common in various locations across the martian south polar residual cap, an area that has been receiving intense scrutiny by the MGS MOC this year, because it is visible on every orbit and in daylight for most of 2005.

    Location near: 86.9oS, 6.9oW Image width: width: 3 km (1.9 mi) Illumination from: upper left Season: Southern Spring

  10. South Polar Ice Cap

    NASA Technical Reports Server (NTRS)

    2003-01-01

    MGS MOC Release No. MOC2-337, 21 April 2003

    This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows the 'swiss cheese' pattern of frozen carbon dioxide on the south polar residual cap. Observation of these materials over two Mars years has revealed that the scarps that bound the mesas and small buttes are retreating-the carbon dioxide ice is subliming away-at a rate of about 3 meters (3 yards) per Mars year in some places. The picture covers an area about 900 m (about 900 yards) wide near 87.1oS, 93.7oW. Sunlight illuminates the scene from the upper left.

  11. Global Core Plasma Model

    NASA Technical Reports Server (NTRS)

    Gallagher, Dennis L.; Craven, P. D.; Comfort, R. H.

    1999-01-01

    Abstract. The Global Core Plasma Model (GCPM) provides, empirically derived, core plasma density as a function of geomagnetic and solar conditions throughout the inner magnetosphere. It is continuous in value and gradient and is composed of separate models for the ionosphere, the plasmasphere, the plasmapause, the trough, and the polar cap. The relative composition of plasmaspheric H+, He+, and O+ is included in the GCPM. A blunt plasmaspheric bulge and rotation of the bulge with changing geomagnetic conditions is included. The GCPM is an amalgam of density models, intended to serve as a framework for continued improvement as new measurements become available and are used to characterize core plasma density, composition, and temperature.

  12. Capping motifs stabilize the leucine-rich repeat protein PP32 and rigidify adjacent repeats.

    PubMed

    Dao, Thuy P; Majumdar, Ananya; Barrick, Doug

    2014-06-01

    Capping motifs are found to flank most β-strand-containing repeat proteins. To better understand the roles of these capping motifs in organizing structure and stability, we carried out folding and solution NMR studies on the leucine-rich repeat (LRR) domain of PP32, which is composed of five tandem LRR, capped by α-helical and β-hairpin motifs on the N- and C-termini. We were able to purify PP32 constructs lacking either cap and containing destabilizing substitutions. Removing the C-cap results in complete unfolding of PP32. Removing the N-cap has a much less severe effect, decreasing stability but retaining much of its secondary structure. In contrast, the dynamics and tertiary structure of the first two repeats are significantly perturbed, based on (1)H-(15)N relaxation studies, chemical shift perturbations, and residual dipolar couplings. However, more distal repeats (3 to C-cap) retain their native tertiary structure. In this regard, the N-cap drives the folding of adjacent repeats from what appears to be a molten-globule-like state. This interpretation is supported by extensive analysis using core packing substitutions in the full-length and N-cap-truncated PP32. This work highlights the importance of caps to the stability and structural integrity of β-strand-containing LRR proteins, and emphasizes the different contributions of the N- and C-terminal caps. PMID:24659532

  13. Regulation of phytochrome message abundance in root caps of maize

    NASA Technical Reports Server (NTRS)

    Johnson, E. M.; Pao, L. I.; Feldman, L. J.

    1991-01-01

    In many cultivars of maize (Zea mays L.) red light affects root development via the photomorphogenetic pigment phytochrome. The site of perception for the light is the root cap. In the maize cultivar Merit, we investigated phytochrome-mediated events in the cap. We established that the message encoded by the phyA1 gene was most abundant in dark-grown tissue and was asymmetrically distributed in the root cap, with greatest expression in the cells which make up the central columella core of the cap. Phytochrome message was negatively autoregulated in a specific region within the root cap. This autoregulation was sensitive to very-low-fluence red light, and thus was characterized as a phytochrome-mediated, very-low-fluence event. The kinetics of message reaccumulation in the dark were also examined and compared to the kinetics of the light requirement for root gravitropism in this cultivar. Similarly, the degree of autoregulation present in two other maize cultivars with different light requirements for gravitropic sensitivity was investigated. It appears that the Merit cultivar expresses a condition of hypersensitivity to phytochrome-mediated light regulation in root tissues. We conclude that phytochrome regulates many activities within the cap, but the degree to which these activities share common phytochrome-mediated steps is not known.

  14. General RNA binding proteins render translation cap dependent.

    PubMed Central

    Svitkin, Y V; Ovchinnikov, L P; Dreyfuss, G; Sonenberg, N

    1996-01-01

    Translation in rabbit reticulocyte lysate is relatively independent of the presence of the mRNA m7G cap structure and the cap binding protein, eIF-4E. In addition, initiation occurs frequently at spurious internal sites. Here we show that a critical parameter which contributes to cap-dependent translation is the amount of general RNA binding proteins in the extract. Addition of several general RNA binding proteins, such as hnRNP A1, La autoantigen, pyrimidine tract binding protein (hnRNP I/PTB) and the major core protein of cytoplasmic mRNP (p50), rendered translation in a rabbit reticulocyte lysate cap dependent. These proteins drastically inhibited the translation of an uncapped mRNA, but had no effect on translation of a capped mRNA. Based on these and other results, we suggest that one function of general mRNA binding proteins in the cytoplasm is to promote ribosome binding by a 5' end, cap-mediated mechanism, and prevent spurious initiations at aberrant translation start sites. Images PMID:9003790

  15. Overexpression of the waaZ Gene Leads to Modification of the Structure of the Inner Core Region of Escherichia coli Lipopolysaccharide, Truncation of the Outer Core, and Reduction of the Amount of O Polysaccharide on the Cell Surface

    PubMed Central

    Frirdich, Emilisa; Lindner, Buko; Holst, Otto; Whitfield, Chris

    2003-01-01

    The waa gene cluster is responsible for the biosynthesis of the lipopolysaccharide (LPS) core region in Escherichia coli and Salmonella. Homologs of the waaZ gene product are encoded by the waa gene clusters of Salmonella enterica and E. coli strains with the K-12 and R2 core types. Overexpression of WaaZ in E. coli and S. enterica led to a modified LPS structure showing core truncations and (where relevant) to a reduction in the amount of O-polysaccharide side chains. Mass spectrometry and nuclear magnetic resonance spectroscopy were used to determine the predominant LPS structures in an E. coli isolate with an R1 core (waaZ is lacking from the type R1 waa gene cluster) with a copy of the waaZ gene added on a plasmid. Novel truncated LPS structures, lacking up to 3 hexoses from the outer core, resulted from WaaZ overexpression. The truncated molecules also contained a KdoIII residue not normally found in the R1 core. PMID:12591884

  16. South Polar Cap

    NASA Technical Reports Server (NTRS)

    2004-01-01

    [figure removed for brevity, see original site]

    Released 8 March 2004

    The Odyssey spacecraft has completed a full Mars year of observations of the red planet. For the next several weeks the Image of the Day will look back over this first mars year. It will focus on four themes: 1) the poles - with the seasonal changes seen in the retreat and expansion of the caps; 2) craters - with a variety of morphologies relating to impact materials and later alteration, both infilling and exhumation; 3) channels - the clues to liquid surface flow; and 4) volcanic flow features. While some images have helped answer questions about the history of Mars, many have raised new questions that are still being investigated as Odyssey continues collecting data as it orbits Mars.

    This image was collected March 5, 2002 during the southern summer season. Layering in the South polar cap interior is readily visible and may indicate yearly ice/dust deposition.

    Image information: VIS instrument. Latitude -86.6, Longitude 156.8 East (203.2 West). 19 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the

  17. Facile synthesis and characterization of highly fluorescent and biocompatible N-acetyl-L-cysteine capped CdTe/CdS/ZnS core/shell/shell quantum dots in aqueous phase.

    PubMed

    Xiao, Qi; Huang, Shan; Su, Wei; Chan, W H; Liu, Yi

    2012-12-14

    The synthesis of water-soluble quantum dots (QDs) in aqueous phase has received much attention recently. To date various kinds of QDs such as CdTe, CdSe, CdTe/CdS and CdSe/ZnS have been synthesized by aqueous methods. However, generally poor-quality QDs (photoluminescent quantum yield (PLQY) lower than 30%) are obtained via this method and the 3-mercaptopropionic acid stabilizer is notorious for its toxicity and awful odor. Here we introduce a novel thiol ligand, N-acetyl-L-cysteine, as an ideal stabilizer that is successfully employed to synthesize high-quality CdTe/CdS/ZnS QDs via a simple aqueous phase. The core/shell/shell structures of the CdTe/CdS/ZnS QDs were verified by x-ray photoelectron spectroscopy, energy dispersive x-ray spectroscopy, x-ray powder diffraction and transmission electron microscopy. These QDs not only possess a high PLQY but also have excellent photostability and favorable biocompatibility, which is vital for many biological applications. This type of water-dispersed QD is a promising candidate for fluorescent probes in biological and medical fields.

  18. CAPS1 Negatively Regulates Hepatocellular Carcinoma Development through Alteration of Exocytosis-Associated Tumor Microenvironment

    PubMed Central

    Xue, Ruyi; Tang, Wenqing; Dong, Pingping; Weng, Shuqiang; Ma, Lijie; Chen, She; Liu, Taotao; Shen, Xizhong; Huang, Xiaowu; Zhang, Si; Dong, Ling

    2016-01-01

    The calcium-dependent activator protein for secretion 1 (CAPS1) regulates exocytosis of dense-core vesicles (DCVs) in neurons and neuroendocrine cells. The role of CAPS1 in cancer biology remains unknown. The purpose of this study was to investigate the role of CAPS1 in hepatocellular carcinoma (HCC). We determined the levels of CAPS1 in eight hepatoma cell lines and 141 HCC specimens. We evaluated the prognostic value of CAPS1 expression and its association with clinical parameters. We investigated the biological consequences of CAPS1 overexpression in two hepatoma cell lines in vitro and in vivo. The results showed that loss of CAPS1 expression in HCC tissues was markedly correlated with aggressive tumor phenotypes, such as high-grade tumor node metastasis (TNM) stage (p = 0.003) and absence of tumor encapsulation (p = 0.016), and was associated with poor overall survival (p = 0.008) and high recurrence (p = 0.015). CAPS1 overexpression inhibited cell proliferation and migration by changing the exocytosis-associated tumor microenvironment in hepatoma cells in vitro. The in vivo study showed that CAPS1 overexpression inhibited xenograft tumor growth. Together, these results identified a previously unrecognized tumor suppressor role for CAPS1 in HCC development. PMID:27689999

  19. Genetics Home Reference: cap myopathy

    MedlinePlus

    ... Groote C, de Jonghe P, Marttila M, Laing NG, Pelin K, Wallgren-Pettersson C. Cap disease caused ... E, Wallefeld W, Memo M, Donner K, Laing NG, Marston S, Grönholm M, Wallgren-Pettersson C. Abnormal actin ...

  20. Stuck fuel rod capping sleeve

    DOEpatents

    Gorscak, Donald A.; Maringo, John J.; Nilsen, Roy J.

    1988-01-01

    A stuck fuel rod capping sleeve to be used during derodding of spent fuel assemblies if a fuel rod becomes stuck in a partially withdrawn position and, thus, has to be severed. The capping sleeve has an inner sleeve made of a lower work hardening highly ductile material (e.g., Inconel 600) and an outer sleeve made of a moderately ductile material (e.g., 304 stainless steel). The inner sleeve may be made of an epoxy filler. The capping sleeve is placed on a fuel rod which is then severed by using a bolt cutter device. Upon cutting, the capping sleeve deforms in such a manner as to prevent the gross release of radioactive fuel material

  1. Direct Binding of Hepatitis C Virus Core to gC1qR on CD4+ and CD8+ T Cells Leads to Impaired Activation of Lck and Akt

    PubMed Central

    Yao, Zhi Qiang; Eisen-Vandervelde, Audrey; Waggoner, Stephen N.; Cale, Evan M.; Hahn, Young S.

    2004-01-01

    Complement plays a pivotal role in the regulation of innate and adaptive immunity. It has been shown that the binding of C1q, a natural ligand of gC1qR, on T cells inhibits their proliferation. Here, we demonstrate that direct binding of the hepatitis C virus (HCV) core to gC1qR on T cells leads to impaired Lck/Akt activation and T-cell function. The HCV core associates with the surface of T cells specifically via gC1qR, as this binding is inhibited by the addition of either anti-gC1qR antibody or soluble gC1qR. The binding affinity constant of core protein for gC1qR, as determined by BIAcore analysis, is 3.8 × 10−7 M. The specificity of the HCV core-gC1qR interaction is confirmed by reduced core binding on Molt-4 T cells treated with gC1qR-silencing small interfering RNA and enhanced core binding on GPC-16 guinea pig cells transfected with human gC1qR. Interestingly, gC1qR is expressed at higher levels on CD8+ than on CD4+ T cells, resulting in more severe core-induced suppression of the CD8+-T-cell population. Importantly, T-cell receptor-mediated activation of the Src kinases Lck and ZAP-70 but not Fyn and the phosphorylation of Akt are impaired by the HCV core, suggesting that it inhibits the very early events of T-cell activation. PMID:15163734

  2. Ferroelectric capped magnetization in multiferroic PZT/LSMO tunnel junctions

    SciTech Connect

    Kumar, Ashok Shukla, A. K.; Barrionuevo, D.; Ortega, N.; Katiyar, Ram S.; Shannigrahi, Santiranjan; Scott, J. F.

    2015-03-30

    Self-poled ultra-thin ferroelectric PbZr{sub 0.52}Ti{sub 0.48}O{sub 3} (PZT) (5 and 7 nm) films have been grown by pulsed laser deposition technique on ferromagnetic La{sub 0.67}Sr{sub 0.33}MnO{sub 3} (LSMO) (30 nm) to check the effect of polar capping on magnetization for ferroelectric tunnel junction devices. PZT/LSMO heterostructures with thick polar PZT (7 nm) capping show nearly 100% enhancement in magnetization compared with thin polar PZT (5 nm) films, probably due to excess hole transfer from the ferroelectric to the ferromagnetic layers. Core-level x-ray photoelectron spectroscopy studies revealed the presence of larger Mn 3s exchange splitting and higher Mn{sup 3+}/Mn{sup 4+} ion ratio in the LSMO with 7 nm polar capping.

  3. Polar Cap Colors

    NASA Technical Reports Server (NTRS)

    2004-01-01

    [figure removed for brevity, see original site]

    Released 12 May 2004 This daytime visible color image was collected on June 6, 2003 during the Southern Spring season near the South Polar Cap Edge.

    The THEMIS VIS camera is capable of capturing color images of the martian surface using its five different color filters. In this mode of operation, the spatial resolution and coverage of the image must be reduced to accommodate the additional data volume produced from the use of multiple filters. To make a color image, three of the five filter images (each in grayscale) are selected. Each is contrast enhanced and then converted to a red, green, or blue intensity image. These three images are then combined to produce a full color, single image. Because the THEMIS color filters don't span the full range of colors seen by the human eye, a color THEMIS image does not represent true color. Also, because each single-filter image is contrast enhanced before inclusion in the three-color image, the apparent color variation of the scene is exaggerated. Nevertheless, the color variation that does appear is representative of some change in color, however subtle, in the actual scene. Note that the long edges of THEMIS color images typically contain color artifacts that do not represent surface variation.

    Image information: VIS instrument. Latitude -77.8, Longitude 195 East (165 West). 38 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA

  4. Which Core Matters More? Differences in Definitions of Quality Lead to New Debates over the Importance of Teaching Practical Skills versus Specific Knowledge

    ERIC Educational Resources Information Center

    Berrett, Dan

    2012-01-01

    Potential students hoping to gauge the quality of courses at Portland State University might be forgiven for feeling confused. On the one hand, the University Studies program, which uses interdisciplinary seminars during the first two years to develop students' core skills, has been widely praised and emulated. The Council for Higher Education…

  5. Myc Regulation of mRNA Cap Methylation

    PubMed Central

    Cowling, Victoria H.; Cole, Michael D.

    2010-01-01

    The c-myc proto-oncogene regulates the expression of 15% to 20% of all genes, depending on the cell type, and the regulation is usually modest (1.5- to 2.0-fold). The authors discovered that in addition to regulating mRNA abundance, c-Myc regulates the formation of the 7-methylguanosine cap on many mRNAs, including transcriptional target genes and others not transcriptionally activated. Because the 7-methylguanosine cap is required for effective translation, enhanced methyl cap formation leads to increased protein production from Myc-responsive genes that exceeds the transcriptional induction. Increased cap methylation is linked to Myc-dependent enhanced activity of 2 critical kinases, TFIIH and p-TEFb, which phosphorylate the RNA polymerase II carboxy-terminal domain (CTD). Phosphorylation of the CTD recruits RNGTT and RNMT, the enzymes involved in mRNA capping, to the nascent transcript. Evidence is accumulating that enhanced cap methylation makes a significant contribution to Myc-dependent gene regulation and protein production. PMID:21170289

  6. Enhanced thermal stability of phosphate capped magnetite nanoparticles

    SciTech Connect

    Muthukumaran, T.; Philip, John

    2014-06-14

    We have studied the effect of phosphate capping on the high temperature thermal stability and magnetic properties of magnetite (Fe{sub 3}O{sub 4}) nanoparticles synthesized through a single-step co-precipitation method. The prepared magnetic nanoparticles are characterized using various techniques. When annealed in air, the phosphate capped nanoparticle undergoes a magnetic to non-magnetic phase transition at a temperature of 689 °C as compared to 580 °C in the uncoated nanoparticle of similar size. The observed high temperature phase stability of phosphate capped nanoparticle is attributed to the formation of a phosphocarbonaceous shell over the nanoparticles, which acts as a covalently attached protective layer and improves the thermal stability of the core material by increasing the activation energy. The phosphocarbonaceous shell prevents the intrusion of heat, oxygen, volatiles, and mass into the magnetic core. At higher temperatures, the coalescence of nanoparticles occurs along with the restructuring of the phosphocarbonaceous shell into a vitreous semisolid layer on the nanoparticles, which is confirmed from the small angle X-ray scattering, Fourier transform infra red spectroscopy, and transmission electron microscopy measurements. The probable mechanism for the enhancement of thermal stability of phosphocarbonaceous capped nanoparticles is discussed.

  7. Investigation about the influence of the mechanical properties of lead core and brass jacket of a NATO 7.62 mm ball bullet in numerical simulations of ballistic impacts

    NASA Astrophysics Data System (ADS)

    Giglio, M.; Gilioli, A.; Manes, A.; Peroni, L.; Scapin, M.

    2012-08-01

    In the present work a validated numerical approach has been used in order to build a robust and reliable FE model of the impact of a NATO 7.62 mm ball bullet, against an aluminium transmission shaft. The bullet is a full metal jacket type, with a lead alloy core and a brass jacket. Target shaft is made by an Al6061-T6 aluminium alloy. According to the soft core (lead alloy) of the bullet, most effort has been spent in order to evaluate the effect of bullet materials mechanical properties on the numerical results. Numerical analyses, carried out using the non-linear dynamic finite element solver Abaqus∖Explicit 6.10, have been performed focusing on core and jacket material behaviour (target material, Al6061-T6, has been previously calibrated by the authors). Thus numerical analyses have been performed considering for the mechanical behaviour of the bullet both a simplified approach (as reported in literature) and new material data (with strain rate effect) obtained by means of experimental tests on the two materials (lead and brass) with specimens cut directly from the bullet. Finally the results of the analyses have been compared with real experimental ballistic tests.

  8. Mathematical modeling of cold cap

    SciTech Connect

    Pokorny, Richard; Hrma, Pavel R.

    2012-10-13

    The ultimate goal of studies of cold cap behavior in glass melters is to increase the rate of glass processing in an energy-efficient manner. Regrettably, mathematical models, which are ideal tools for assessing the responses of melters to process parameters, have not paid adequate attention to the cold cap. In this study, we consider a cold cap resting on a pool of molten glass from which it receives a steady heat flux while temperature, velocity, and extent of conversion are functions of the position along the vertical coordinate. A one-dimensional (1D) mathematical model simulates this process by solving the differential equations for mass and energy balances with appropriate boundary conditions and constitutive relationships for material properties. The sensitivity analyses on the effects of incoming heat fluxes to the cold cap through its lower and upper boundaries show that the cold cap thickness increases as the heat flux from above increases, and decreases as the total heat flux increases. We also discuss the effects of foam, originating from batch reactions and from redox reactions in molten glass and argue that models must represent the foam layer to achieve a reliable prediction of the melting rate as a function of feed properties and melter conditions.

  9. Polar Cap Plasma and Convection

    NASA Technical Reports Server (NTRS)

    Elliott, Heather A.; Craven, Paul D.; Comfort, Richard H.; Chandler, Michael O.; Moore, Thomas E.; Ruohoniemi, J. M.

    1998-01-01

    This presentation will describe the character of the polar cap plasma in 10% AGU Spring 1998 particular the convection velocities at the perigee (about 1.8 Re) and apogee( about 8.9 Re) of Polar in relationship to Interplanetary Magnetic Field (IMF) and solar wind parameters. This plasma is thought to be due to several sources; the polar wind, cleft ion fountain, and auroral outflow. The plasma in the polar cap tends to be mostly field-aligned. At any given point in the polar cap, this plasma could be from a different regions since convection of magnetic field lines can transport this material. it is quite difficult to study such a phenomena with single point measurements. Current knowledge of the polar cap plasma obtained by in situ measurements will be presented along with recent results from the Polar mission. This study also examines the direct electrical coupling between the magnetosphere and ionosphere by comparing convection velocities measured by the Thermal Ion Dynamics Experiment (TIDE) and Magnetic Field Experiment (MFE) instruments in magnetosphere and measurements of the ionosphere by ground-based radars. At times such a comparison is difficult because the Polar satellite at apogee spends a large amount of time in the polar cap which is a region that is not coverage well by the current SuperDam coherent radars. This is impart due to the lack of irregularities that returns the radar signal.

  10. South Polar Residual Ice Cap

    NASA Technical Reports Server (NTRS)

    1990-01-01

    This mosaic is composed of 18 Viking Orbiter images (6 each in red, green, and violet filters), acquired on September 28, 1977, during revolution 407 of Viking Orbiter 2. The south pole is located just off the lower left edge of the polar cap, and the 0 degree longitude meridian extends toward the top of the mosaic. The large crater near the right edge (named 'South') is about 100 km in diameter. These images were acquired during southern summer on Mars (Ls = 341 degrees); the sub-solar declination was 8 degrees S., and the south polar cap was nearing its final stage of retreat just prior to vernal equinox. The south residual cap is approximately 400 km across, and the exposed surface is thought to consist dominantly of carbon-dioxide frost. This is in contrast to the water-ice surface of the north polar residual cap. It is likely that water ice is present in layers that underlie the south polar cap and that comprise the surrounding layered terrains. Near the top of this image, irregular pits with sharp-rimmed cliffs appear 'etched', presumably by wind. A series of rugged mountains (extending toward the upper right corner of the image) are of unknown origin.

  11. The Drangajökull ice cap, northwest Iceland, persisted into the early-mid Holocene

    NASA Astrophysics Data System (ADS)

    Schomacker, Anders; Brynjólfsson, Skafti; Andreassen, Julie M.; Gudmundsdóttir, Esther Ruth; Olsen, Jesper; Odgaard, Bent V.; Håkansson, Lena; Ingólfsson, Ólafur; Larsen, Nicolaj K.

    2016-09-01

    Most glaciers and ice caps in Iceland experienced rapid deglaciation in the early Holocene, reaching a minimum extent during the Holocene Thermal Maximum. Here we present evidence of the Holocene glacial history from lake sediment cores retrieved from seven threshold lakes around the Drangajökull ice cap in the Vestfirðir peninsula, NW Iceland. The sediment cores show on/off signals of glacial meltwater activity, as minerogenic material deposited from glacial meltwater alternates with organic-rich material (gyttja) deposited without glacial meltwater. We base the chronology of the sediment cores on 14C ages and geochemical identification of key tephra layers with known ages. A 25-cm thick layer of the Saksunarvatn tephra in Lake Skorarvatn indicates that the northern part of the ice cap had reached a similar size as today or was smaller already by 10.2 cal kyr BP. However, 14C ages of lake sediment cores from the highlands southeast of Drangajökull suggest that this part of the ice cap was larger than today until 7.8-7.2 cal kyr BP. Even today, the Drangajökull ice cap has a different behavior than the main ice caps in Iceland, characterized by a very low glaciation limit. Because palaeoclimatic proxies show an early-mid Holocene temperature optimum in this part of Iceland, we suggest that the persistence of Drangajökull into the early Holocene and, possibly, also the entire Holocene was due to high winter precipitation.

  12. Polar Cap Formation on Ganymede

    NASA Technical Reports Server (NTRS)

    Pilcher, C. B.; Shaya, E. J.

    1985-01-01

    Since thermal migration is not an effective mechanism for water transport in the polar regions at the Galilean satellites, some other process must be responsible for the formation of Ganymede's polar caps. It is proposed that Ganymede's polar caps are the optical manifestation of a process that began with the distribution of an ice sheet over the surface of Ganymede. The combined processes of impact gardening and thermal migration led, in regions at latitudes less than 40 to 45 deg., to the burial of some fraction of this ice, the migration of some to the polar caps margins, and a depletion of free ice in the optical surface. At higher latitudes, no process was effective in removing ice from the optical surface, so the remanants of the sheet are visible today.

  13. Polar cap formation on Ganymede

    NASA Technical Reports Server (NTRS)

    Shaya, E. J.; Pilcher, C. B.

    1984-01-01

    It is argued that Ganymede's polar caps are the remnants of a more extensive covering of water ice that formed during a period in which the satellite was geologically active. It is inferred that the initial thickness of this covering was a significant fraction of the gardening depth since the covering formed. This suggests an initial thickness of at least a few meters over heavily cratered regions such as the south polar grooved terrain. The absence of similar polar caps on Callisto apparently reflects the absence of comparable geologic activity in the history of this satellite.

  14. The Enigmatic Martian Polar Caps

    SciTech Connect

    James, Philip

    2005-08-17

    The Martian polar caps have puzzled astronomers for over a century. Extensive study by many instruments on various spacecraft has resolved many questions but has at the same time created a new generation of puzzles. The polar caps are intimately coupled to the current Martian climate and volatile cycles. They also hold clues to climate variations on a variety of longer time scales. The results of recent missions will be reviewed, and the potential outlook for resolution of the outstanding questions will be examined.

  15. Immunization with Recombinant Adenoviral Vectors Expressing HCV Core or F Proteins Leads to T Cells with Reduced Effector Molecules Granzyme B and IFN-γ: A Potential New Strategy for Immune Evasion in HCV Infection.

    PubMed

    Samrat, Subodh Kumar; Vedi, Satish; Singh, Shakti; Li, Wen; Kumar, Rakesh; Agrawal, Babita

    2015-01-01

    Multispecific, broad, and potent T cell responses have been correlated with viral clearance in hepatitis C virus (HCV) infection. However, the majority of infected patients develop chronic infection, suggesting that natural infection mostly leads to development of inefficient T cell immunity. Multiple mechanisms of immune modulation and evasion have been shown in HCV infection through various investigations. This study examined the generation and modulation of T cell responses against core and frameshift (F) proteins of HCV. A single immunization of mice with replication incompetent recombinant adenovirus vectors encoding for F or core antigens induces poor T cell responses and leads to generation of CD4+ and CD8+ T cells with low granzyme B (GrB) expression. These T cells have impaired GrB enzyme activity and are unable to kill peptide loaded target cells. The low intracellular expression of GrB is not due to degranulation of cytotoxic granules containing cytotoxic T cells. Addition of exogenous IL-2 in in vitro cultures leads to partial recovery of GrB production, whereas immunization with the Toll-like receptor (TLR) agonist poly I:C leads to complete restoration of GrB expression in both CD4+ and CD8+ T cells. Thus, a possible new strategy of T cell modulation is recognized wherein effector T cells are caused to be dysfunctional by HCV-derived antigens F or core, and strategies are also delineated to overcome this dysfunction. These studies are important in the investigation of prophylactic vaccine and immunotherapy strategies for HCV infection.

  16. Holocene fluctuations of Bregne ice cap, Scoresby Sund, eastern Greenland

    NASA Astrophysics Data System (ADS)

    Levy, L.; Kelly, M. A.; Lowell, T. V.; Hall, B. L.

    2011-12-01

    TML. 10Be ages of boulders and bedrock just outside these moraines indicate that deglaciation occurred at 10.4±0.5 ka and that the moraines mark the maximum ice extent during the Holocene. Beginning in the early Holocene, the ice cap then had either entirely retreated from the TML basin or contributed minimal sediment input until ~2,800 cal yr BP when clay-rich, finely laminated sediments begin to occur. This chronology is in contrast to small ice caps located in Liverpool Land, 130 km east of Milne Land. In Liverpool Land, lake sediment records indicate that the onset of Neoglaciation occurred at ~800 cal yr BP. The difference between the onset of Neoglaciation in western and eastern Scoresby Sund may be due to differences in basin position relative to the ice cap or may represent a temperature gradient between the inland, high elevation of Bregne ice cap and the coastal, low elevation Liverpool Land ice caps. Other records, such as GRIP borehole temperatures and the δ18O record from the Renland ice cap show cooling from ~4,500-2,000 yr BP suggesting that the terrestrial advances of ice caps in Scoresby Sund lagged behind temperatures registered in ice cores or ice core records are not good proxies for changes at the ice margins.

  17. Gold nanoparticles with different capping systems: an electronic and structural XAS analysis.

    PubMed

    López-Cartes, C; Rojas, T C; Litrán, R; Martínez-Martínez, D; de la Fuente, J M; Penadés, S; Fernández, A

    2005-05-12

    Gold nanoparticles (NPs) have been prepared with three different capping systems: a tetralkylammonium salt, an alkanethiol, and a thiol-derivatized neoglycoconjugate. Also gold NPs supported on a porous TiO(2) substrate have been investigated. X-ray absorption spectroscopy (XAS) has been used to determine the electronic behavior of the different capped/supported systems regarding the electron/hole density of d states. Surface and size effects, as well as the role of the microstructure, have been also studied through an exhaustive analysis of the EXAFS (extended X-ray absorption fine structure) data. Very small gold NPs functionalized with thiol-derivatized molecules show an increase in d-hole density at the gold site due to Au-S charge transfer. This effect is overcoming size effects (which lead to a slightly increase of the d-electron density) for high S:Au atomic ratios and core-shell microstructures where an atomically abrupt Au-S interface likely does not exist. It has been also shown that thiol functionalization of very small gold NPs is introducing a strong distortion as compared to fcc order. To the contrary, electron transfer from reduced support oxides to gold NPs can produce a higher increase in d-electron density at the gold site, as compared to naked gold clusters. PMID:16852039

  18. Gold nanoparticles with different capping systems: an electronic and structural XAS analysis.

    PubMed

    López-Cartes, C; Rojas, T C; Litrán, R; Martínez-Martínez, D; de la Fuente, J M; Penadés, S; Fernández, A

    2005-05-12

    Gold nanoparticles (NPs) have been prepared with three different capping systems: a tetralkylammonium salt, an alkanethiol, and a thiol-derivatized neoglycoconjugate. Also gold NPs supported on a porous TiO(2) substrate have been investigated. X-ray absorption spectroscopy (XAS) has been used to determine the electronic behavior of the different capped/supported systems regarding the electron/hole density of d states. Surface and size effects, as well as the role of the microstructure, have been also studied through an exhaustive analysis of the EXAFS (extended X-ray absorption fine structure) data. Very small gold NPs functionalized with thiol-derivatized molecules show an increase in d-hole density at the gold site due to Au-S charge transfer. This effect is overcoming size effects (which lead to a slightly increase of the d-electron density) for high S:Au atomic ratios and core-shell microstructures where an atomically abrupt Au-S interface likely does not exist. It has been also shown that thiol functionalization of very small gold NPs is introducing a strong distortion as compared to fcc order. To the contrary, electron transfer from reduced support oxides to gold NPs can produce a higher increase in d-electron density at the gold site, as compared to naked gold clusters.

  19. Label-free molecular detection with capped carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Koleini, Mohammad; Colombi Ciacchi, Lucio

    2013-02-01

    We present a theoretical proof-of-principle analysis of a device composed of mutually faced capped carbon nanotubes for the selective detection of hardly distinguishable gas molecules in binary mixtures (methanol/formaldehyde and H2O/H2S). Selectivity arises, on one side, from I-V responses of the sensor in the presence of different gases trapped between the nanotube caps. On the other side, the different dipole moments and polarizabilities of the molecules lead to different population probabilities in the sensing region, acting as a highly selective electrostatic trapping device. The selectivity can be tuned by the bias voltage and by the gap distance between the nanotubes.

  20. Indirect pulp capping: a survey.

    PubMed

    Kaplowitz, G J

    1992-01-01

    This study addresses the acceptance of the clinical practice of indirect pulp capping. State and regional dental boards and postgraduate dental education programs throughout the United States were surveyed. Results indicate that no clear consensus exists for the acceptance of this clinical procedure.

  1. From Blogs to Bottle Caps

    ERIC Educational Resources Information Center

    Edinger, Ted

    2012-01-01

    There is a wonderful community of art educators connecting a once-isolated profession through blogging. Art educators around the world are sharing ideas and communicating with their peers through this amazing resource. In this article, the author describes the bottle cap mural at Tulip Grove Elementary School which was inspired by this exchange of…

  2. A new approach for quantifying cumulative, anthropogenic, atmospheric lead deposition using peat cores from bogs: Pb in eight Swiss peat bog profiles.

    PubMed

    Shotyk, W; Blaser, P; Grünig, A; Cheburkin, A K

    2000-04-17

    Peat cores taken from eight Swiss peatlands were used to calculate inventories of anthropogenic Pb using either Sc or Zr to quantify Pb derived from rock weathering. The shapes of the Pb/Sc and Pb/Zr profiles suggest that Pb was supplied exclusively by atmospheric deposition at all sites. At one of the sites (Etang de la Gruère), anthropogenic Pb was calculated using both Sc and Zr as the conservative reference element. Lithogenic Pb determined using Sc was twice that obtained using Zr, possibly because Zr resides only in zircons which are dense compared to pyroxene and amphibole which are the main Sc-bearing phases in the earth's crust. However, the inventory of 'natural' Pb (supplied almost entirely by soil dust) is dwarfed by the anthropogenic inventory such that anthropogenic Pb calculated using Sc and Zr agree to within 5%. The total amount of anthropogenic Pb accumulated in the bogs was calculated by simply adding the mass of anthropogenic Pb for each peat slice over the length of each core. Cumulative, anthropogenic Pb calculated in this way ranged from 1.0 to 9.7 g/m2 and showed pronounced regional differences: the site south of the Alps (Gola di Lago in Canton Ticino) with direct exposure to the heavily industrialized region of northern Italy received nearly 10 times more anthropogenic Pb as the sites in more remote alpine regions (Schöpfenwaldmoor in Canton Berne, and Mauntschas in Canton Grisons). The approach used here to calculate cumulative, anthropogenic, atmospheric Pb (CAAPb) is simple and robust, independent of the chronology of Pb deposition, and makes no assumptions about the immobility of Pb within the peat profile. Given the worldwide distribution of peat bogs, it should be possible to undertake continental and global inventories of atmospheric metal deposition, for both the natural and anthropogenic components of most trace metals of environmental interest.

  3. Reduced blinking behavior of single 2-mercapto ethanol capped CdTe quantum dots

    NASA Astrophysics Data System (ADS)

    Mandal, Abhijit; Tamai, Naoto

    2013-11-01

    Water soluble small size CdTe QDs were synthesized by using 2-mercapto ethanol (2ME) as stabilizer. The optimum size of QDs was obtained after certain time of reflux. Synthesized 2ME capped CdTe QDs show large Stokes shifted photoluminescence. At the single particle detection level, 2ME capped CdTe QDs showed reduced blinking behavior compared to that of TGA capped CdTe QDs. These results indicate that the thiol moiety of 2ME, which is a strong electron donor, saturated the surface traps with electrons, preventing the traps from accepting the Auger ionized electrons from the core of CdTe QD.

  4. Ultrastable BSA-capped gold nanoclusters with a polymer-like shielding layer against reactive oxygen species in living cells.

    PubMed

    Zhou, Wenjuan; Cao, Yuqing; Sui, Dandan; Guan, Weijiang; Lu, Chao; Xie, Jianping

    2016-05-01

    The prevalence of reactive oxygen species (ROS) production and the enzyme-containing intracellular environment could lead to the fluorescence quenching of bovine serum albumin (BSA)-capped gold nanoclusters (AuNCs). Here we report an efficient strategy to address this issue, where a polymer-like shielding layer is designed to wrap around the Au core to significantly improve the stability of AuNCs against ROS and protease degradation. The key of our design is to covalently incorporate a thiolated AuNC into the BSA-AuNC via carbodiimide-activated coupling, leading to the formation of a AuNC pair inside the cross-linked BSA molecule. The as-designed paired AuNCs in BSA (or BSA-p-AuNCs for short) show improved performances in living cells.

  5. Functional end-capped conducting poly (3,4-ethylenedioxythiophene)

    NASA Astrophysics Data System (ADS)

    Sabatini, V.; Farina, H.; Ortenzi, Marco A.

    2016-05-01

    Methacrylate-terminated Poly(3,4-Ethylenedioxythiophene) (PEDOT) polymers with controlled degree of polymerization were successfully prepared by direct oxidative polycondensation between Ethylenedioxythiophene (EDOT) and a cross-linkable methacrylate end-capper monomer, obtained via Friedel Crafts acylation starting from EDOT and Methacryloyl chloride. The new polymer was synthesized in order to overcome the well-known technical problems of PEDOT, i.e. difficult processability and patterning, due to its poor solubility in common organic and inorganic solvents. The chemical structure and the degree of polymerization of the end-capped polymers were determined by 1H NMR spectra. A new synthesis of Methacrylate end-capped PEDOT with controlled degree of polymerization, soluble in common organic and chlorinated solvents and with improved conductivity, 210 S/cm, was performed. This method includes: direct oxidative polycondensation of 3,4-Ethylenedioxythiophene (EDOT) in the presence of a cross-linkable end-capper, i.e. Methacrylate end-capped EDOT prepared via Friedel Crafts acylation with Methacryloyl chloride and oxidant species, i.e. ferric sulfate. Furthermore, the oxidative polycondensation of EDOT monomer and Methacrylate end-capped EDOT in the presence of Sulfonated Polyethersulfone (SPES)- characterized by different degree of Sulfonation (DS)- as dopant agent was performed, leading to functional end-capped conducting PEDOT, easy to process and pattern, with conductivity of 210 S/cm, 50 S/cm higher than the one of commercial PEDOT.

  6. Tip cap for a rotor blade

    NASA Technical Reports Server (NTRS)

    Kofel, W. K.; Tuley, E. N.; Gay, C. H., Jr.; Troeger, R. E.; Sterman, A. P. (Inventor)

    1983-01-01

    A replaceable tip cap for attachment to the end of a rotor blade is described. The tip cap includes a plurality of walls defining a compartment which, if desired, can be divided into a plurality of subcompartments. The tip cap can include inlet and outlet holes in walls thereof to permit fluid communication of a cooling fluid there through. Abrasive material can be attached with the radially outer wall of the tip cap.

  7. Ultrastable BSA-capped gold nanoclusters with a polymer-like shielding layer against reactive oxygen species in living cells

    NASA Astrophysics Data System (ADS)

    Zhou, Wenjuan; Cao, Yuqing; Sui, Dandan; Guan, Weijiang; Lu, Chao; Xie, Jianping

    2016-05-01

    The prevalence of reactive oxygen species (ROS) production and the enzyme-containing intracellular environment could lead to the fluorescence quenching of bovine serum albumin (BSA)-capped gold nanoclusters (AuNCs). Here we report an efficient strategy to address this issue, where a polymer-like shielding layer is designed to wrap around the Au core to significantly improve the stability of AuNCs against ROS and protease degradation. The key of our design is to covalently incorporate a thiolated AuNC into the BSA-AuNC via carbodiimide-activated coupling, leading to the formation of a AuNC pair inside the cross-linked BSA molecule. The as-designed paired AuNCs in BSA (or BSA-p-AuNCs for short) show improved performances in living cells.The prevalence of reactive oxygen species (ROS) production and the enzyme-containing intracellular environment could lead to the fluorescence quenching of bovine serum albumin (BSA)-capped gold nanoclusters (AuNCs). Here we report an efficient strategy to address this issue, where a polymer-like shielding layer is designed to wrap around the Au core to significantly improve the stability of AuNCs against ROS and protease degradation. The key of our design is to covalently incorporate a thiolated AuNC into the BSA-AuNC via carbodiimide-activated coupling, leading to the formation of a AuNC pair inside the cross-linked BSA molecule. The as-designed paired AuNCs in BSA (or BSA-p-AuNCs for short) show improved performances in living cells. Electronic supplementary information (ESI) available: Detailed experimental materials, apparatus, experimental procedures and characterization data. See DOI: 10.1039/c6nr02178f

  8. Climate-related changes in lead isotopes over the past 800,000 years in the EPICA Dome C Antarctic ice core

    NASA Astrophysics Data System (ADS)

    Han, C.; Hur, S.; Burn, L. J.; Gabrielli, P.; Vallelonga, P. T.; Barbante, C.; Boutron, C. F.; Hong, S.

    2013-12-01

    A record of Pb isotopic compositions from 3,260 m deep Antarctic ice, recovered at Dome C on the East Antarctic plateau, and covering the past 800 kyr, is presented. Pb isotopic compositions have been determined using thermal ionization mass spectrometry (TRITON, Thermo Scientific). All sample handling and analytical operations were performed inside a Class 1 - Class 10 clean room provided with High Efficiency Particulate Air (HEPA) multi-staged filtration (Curtin University) and under a class 10 laminar airflow bench or booth in class 1000 clean laboratories (KOPRI). Lower 206Pb/207Pb ratios are found during glacial periods when Pb concentrations are high, while higher values are found during warm periods when Pb concentrations are low. The characteristics of Pb isotopes vary with climatic conditions, which is likely associated with the relative strength of dust and volcanic contributions to Pb deposition in central East Antarctica. Using Pb, Sr and Nd isotopes in Antarctic deep ice cores, previous studies suggested that Southern South America (SSA) was an important source of dust in Antarctic ice during both glacial and interglacial periods, with negligible contributions from Australian mineral dust. Here we present the first Pb isotopic evidence that dust from Eastern Australia could be an important source of Antarctic dust between 300 kyr BP and 600 kry BP.

  9. 47 CFR 54.507 - Cap.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Universal Service Support for Schools and Libraries § 54.507 Cap. (a) Amount of the annual cap. The annual funding cap on federal universal service support for schools and libraries shall be $2.25 billion per... into subsequent funding years for use in the schools and libraries support mechanism in accordance...

  10. Dynamic Modeling of an Evapotranspiration Cap

    SciTech Connect

    Jacob J. Jacobson; Steven Piet; Rafael Soto; Gerald Sehlke; Harold Heydt; John Visser

    2005-10-01

    The U.S. Department of Energy is scheduled to design and install hundreds of landfill caps/barriers over the next several decades and these caps will have a design life expectancy of up to 1,000 years. Other landfill caps with 30 year design lifetimes are reaching the end of their original design life; the changes to these caps need to be understood to provide a basis for lifetime extension. Defining the attributes that make a successful cap (one that isolates the waste from the environment) is crucial to these efforts. Because cap systems such as landfill caps are dynamic in nature, it is impossible to understand, monitor, and update lifetime predictions without understanding the dynamics of cap degradation, which is most often due to multiple interdependent factors rather than isolated independent events. In an attempt to understand the dynamics of cap degradation, a computer model using system dynamics is being developed to capture the complex behavior of an evapotranspiration cap. The specific objectives of this project are to capture the dynamic, nonlinear feedback loop structures underlying an evapotranspiration cap and, through computer simulation, gain a better understanding of long-term behavior, influencing factors, and, ultimately, long-term cap performance.

  11. Indoleacetic acid movement in the root cap.

    PubMed

    Pernet, J J; Pilet, P E

    1976-01-01

    When applied on the root cap of Zea mays L., indol-3yl-acetic acid (IAA) may enter the root tip and move basipetally inside the cap. From the cap to the apex (quiescent centre and meristem) the IAA transport is very slow. Polarity of IAA movement, in relation to growth, is discussed.

  12. 21 CFR 888.3000 - Bone cap.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Bone cap. 888.3000 Section 888.3000 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3000 Bone cap. (a) Identification. A bone cap is a...

  13. 21 CFR 888.3000 - Bone cap.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Bone cap. 888.3000 Section 888.3000 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3000 Bone cap. (a) Identification. A bone cap is a...

  14. 21 CFR 888.3000 - Bone cap.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Bone cap. 888.3000 Section 888.3000 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3000 Bone cap. (a) Identification. A bone cap is a...

  15. 47 CFR 54.507 - Cap.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... schools and libraries support mechanism in accordance with the public interest and notwithstanding the... schools and libraries mechanism in accordance with the public interest and notwithstanding the annual cap... Universal Service Support for Schools and Libraries § 54.507 Cap. (a) Amount of the annual cap. In...

  16. 47 CFR 54.507 - Cap.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... schools and libraries support mechanism in accordance with the public interest and notwithstanding the... schools and libraries mechanism in accordance with the public interest and notwithstanding the annual cap... Universal Service Support for Schools and Libraries § 54.507 Cap. (a) Amount of the annual cap. In...

  17. 21 CFR 888.3000 - Bone cap.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Bone cap. 888.3000 Section 888.3000 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3000 Bone cap. (a) Identification. A bone cap is a...

  18. 21 CFR 884.5250 - Cervical cap.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Cervical cap. 884.5250 Section 884.5250 Food and... OBSTETRICAL AND GYNECOLOGICAL DEVICES Obstetrical and Gynecological Therapeutic Devices § 884.5250 Cervical cap. (a) Identification. A cervical cap is a flexible cuplike receptacle that fits over the cervix...

  19. 21 CFR 884.5250 - Cervical cap.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Cervical cap. 884.5250 Section 884.5250 Food and... OBSTETRICAL AND GYNECOLOGICAL DEVICES Obstetrical and Gynecological Therapeutic Devices § 884.5250 Cervical cap. (a) Identification. A cervical cap is a flexible cuplike receptacle that fits over the cervix...

  20. 21 CFR 884.5250 - Cervical cap.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Cervical cap. 884.5250 Section 884.5250 Food and... OBSTETRICAL AND GYNECOLOGICAL DEVICES Obstetrical and Gynecological Therapeutic Devices § 884.5250 Cervical cap. (a) Identification. A cervical cap is a flexible cuplike receptacle that fits over the cervix...

  1. 21 CFR 884.5250 - Cervical cap.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Cervical cap. 884.5250 Section 884.5250 Food and... OBSTETRICAL AND GYNECOLOGICAL DEVICES Obstetrical and Gynecological Therapeutic Devices § 884.5250 Cervical cap. (a) Identification. A cervical cap is a flexible cuplike receptacle that fits over the cervix...

  2. Surface mass balance of Greenland mountain glaciers and ice caps

    NASA Astrophysics Data System (ADS)

    Benson, R. J.; Box, J. E.; Bromwich, D. H.; Wahr, J. M.

    2009-12-01

    Mountain glaciers and ice caps contribute roughly half of eustatic sea-level rise. Greenland has thousands of small mountain glaciers and several ice caps > 1000 sq. km that have not been included in previous mass balance calculations. To include small glaciers and ice caps in our study, we use Polar WRF, a next-generation regional climate data assimilation model is run at grid resolution less than 10 km. WRF provides surface mass balance data at sufficiently high resolution to resolve not only the narrow ice sheet ablation zone, but provides information useful in downscaling melt and accumulation rates on mountain glaciers and ice caps. In this study, we refine Polar WRF to simulate a realistic surface energy budget. Surface melting is calculated in-line from surface energy budget closure. Blowing snow sublimation is computed in-line. Melt water re-freeze is calculated using a revised scheme. Our results are compared with NASA's Gravity Recovery and Climate Experiment (GRACE) and associated error is calculated on a regional and local scale with validation from automated weather stations (AWS), snow pits and ice core data from various regions along the Greenland ice sheet.

  3. CAP2 in cardiac conduction, sudden cardiac death and eye development.

    PubMed

    Field, Jeffrey; Ye, Diana Z; Shinde, Manasi; Liu, Fang; Schillinger, Kurt J; Lu, MinMin; Wang, Tao; Skettini, Michelle; Xiong, Yao; Brice, Angela K; Chung, Daniel C; Patel, Vickas V

    2015-11-30

    Sudden cardiac death kills 180,000 to 450,000 Americans annually, predominantly males. A locus that confers a risk for sudden cardiac death, cardiac conduction disease, and a newly described developmental disorder (6p22 syndrome) is located at 6p22. One gene at 6p22 is CAP2, which encodes a cytoskeletal protein that regulates actin dynamics. To determine the role of CAP2 in vivo, we generated knockout (KO) mice. cap2(-)/cap2(-) males were underrepresented at weaning and ~70% died by 12 weeks of age, but cap2(-)/cap2(-) females survived at close to the expected levels and lived normal life spans. CAP2 knockouts resembled patients with 6p22 syndrome in that mice were smaller and they developed microphthalmia and cardiac disease. The cardiac disease included cardiac conduction disease (CCD) and, after six months of age, dilated cardiomyopathy (DCM), most noticeably in the males. To address the mechanisms underlying these phenotypes, we used Cre-mediated recombination to knock out CAP2 in cardiomyocytes. We found that the mice developed CCD, leading to sudden cardiac death from complete heart block, but no longer developed DCM or the other phenotypes, including sex bias. These studies establish a direct role for CAP2 and actin dynamics in sudden cardiac death and cardiac conduction disease.

  4. Neuronal Actin Dynamics, Spine Density and Neuronal Dendritic Complexity Are Regulated by CAP2.

    PubMed

    Kumar, Atul; Paeger, Lars; Kosmas, Kosmas; Kloppenburg, Peter; Noegel, Angelika A; Peche, Vivek S

    2016-01-01

    Actin remodeling is crucial for dendritic spine development, morphology and density. CAP2 is a regulator of actin dynamics through sequestering G-actin and severing F-actin. In a mouse model, ablation of CAP2 leads to cardiovascular defects and delayed wound healing. This report investigates the role of CAP2 in the brain using Cap2(gt/gt) mice. Dendritic complexity, the number and morphology of dendritic spines were altered in Cap2(gt/gt) with increased number of excitatory synapses. This was accompanied by increased F-actin content and F-actin accumulation in cultured Cap2(gt/gt) neurons. Moreover, reduced surface GluA1 was observed in mutant neurons under basal condition and after induction of chemical LTP. Additionally, we show an interaction between CAP2 and n-cofilin, presumably mediated through the C-terminal domain of CAP2 and dependent on cofilin Ser3 phosphorylation. In vivo, the consequences of this interaction were altered phosphorylated cofilin levels and formation of cofilin aggregates in the neurons. Thus, our studies identify a novel role of CAP2 in neuronal development and neuronal actin dynamics. PMID:27507934

  5. CAP2 in cardiac conduction, sudden cardiac death and eye development

    PubMed Central

    Field, Jeffrey; Ye, Diana Z.; Shinde, Manasi; Liu, Fang; Schillinger, Kurt J.; Lu, MinMin; Wang, Tao; Skettini, Michelle; Xiong, Yao; Brice, Angela K.; Chung, Daniel C.; Patel, Vickas V.

    2015-01-01

    Sudden cardiac death kills 180,000 to 450,000 Americans annually, predominantly males. A locus that confers a risk for sudden cardiac death, cardiac conduction disease, and a newly described developmental disorder (6p22 syndrome) is located at 6p22. One gene at 6p22 is CAP2, which encodes a cytoskeletal protein that regulates actin dynamics. To determine the role of CAP2 in vivo, we generated knockout (KO) mice. cap2−/cap2− males were underrepresented at weaning and ~70% died by 12 weeks of age, but cap2−/cap2− females survived at close to the expected levels and lived normal life spans. CAP2 knockouts resembled patients with 6p22 syndrome in that mice were smaller and they developed microphthalmia and cardiac disease. The cardiac disease included cardiac conduction disease (CCD) and, after six months of age, dilated cardiomyopathy (DCM), most noticeably in the males. To address the mechanisms underlying these phenotypes, we used Cre-mediated recombination to knock out CAP2 in cardiomyocytes. We found that the mice developed CCD, leading to sudden cardiac death from complete heart block, but no longer developed DCM or the other phenotypes, including sex bias. These studies establish a direct role for CAP2 and actin dynamics in sudden cardiac death and cardiac conduction disease. PMID:26616005

  6. Neuronal Actin Dynamics, Spine Density and Neuronal Dendritic Complexity Are Regulated by CAP2

    PubMed Central

    Kumar, Atul; Paeger, Lars; Kosmas, Kosmas; Kloppenburg, Peter; Noegel, Angelika A.; Peche, Vivek S.

    2016-01-01

    Actin remodeling is crucial for dendritic spine development, morphology and density. CAP2 is a regulator of actin dynamics through sequestering G-actin and severing F-actin. In a mouse model, ablation of CAP2 leads to cardiovascular defects and delayed wound healing. This report investigates the role of CAP2 in the brain using Cap2gt/gt mice. Dendritic complexity, the number and morphology of dendritic spines were altered in Cap2gt/gt with increased number of excitatory synapses. This was accompanied by increased F-actin content and F-actin accumulation in cultured Cap2gt/gt neurons. Moreover, reduced surface GluA1 was observed in mutant neurons under basal condition and after induction of chemical LTP. Additionally, we show an interaction between CAP2 and n-cofilin, presumably mediated through the C-terminal domain of CAP2 and dependent on cofilin Ser3 phosphorylation. In vivo, the consequences of this interaction were altered phosphorylated cofilin levels and formation of cofilin aggregates in the neurons. Thus, our studies identify a novel role of CAP2 in neuronal development and neuronal actin dynamics. PMID:27507934

  7. Radiation Characterization Summary: ACRR Polyethylene-Lead-Graphite (PLG) Bucket Located in the Central Cavity on the 32-Inch Pedestal at the Core Centerline (ACRR-PLG-CC-32-cl).

    SciTech Connect

    Parma, Edward J.,; Vehar, David W.; Lippert, Lance L.; Griffin, Patrick J.; Naranjo, Gerald E.; Luker, Spencer M.

    2015-06-01

    This document presents the facility-recommended characterization of the neutron, prompt gamma-ray, and delayed gamma-ray radiation fields in the Annular Core Research Reactor (ACRR) for the polyethylene-lead-graphite (PLG) bucket in the central cavity on the 32-inch pedestal at the core centerline. The designation for this environment is ACRR-PLG-CC-32-cl. The neutron, prompt gamma-ray, and delayed gamma-ray energy spectra, uncertainties, and covariance matrices are presented as well as radial and axial neutron and gamma-ray fluence profiles within the experiment area of the bucket. Recommended constants are given to facilitate the conversion of various dosimetry readings into radiation metrics desired by experimenters. Representative pulse operations are presented with conversion examples. Acknowledgements The authors wish to thank the Annular Core Research Reactor staff and the Radiation Metrology Laboratory staff for their support of this work. Also thanks to David Ames for his assistance in running MCNP on the Sandia parallel machines.

  8. Structural characterisation of alkyl amine-capped zinc sulphide nanoparticles.

    PubMed

    Kremser, Gabriele; Rath, Thomas; Kunert, Birgit; Edler, Michael; Fritz-Popovski, Gerhard; Resel, Roland; Letofsky-Papst, Ilse; Grogger, Werner; Trimmel, Gregor

    2012-03-01

    Nanoparticles capped with amine ligands with different steric properties, dodecylamine and oleylamine, respectively, are investigated in the solid state as well as in solution. A combined X-ray diffraction, small angle X-ray scattering and electron microscopy investigation showed that the nanoparticles exhibit the sphalerite modification of ZnS as crystal phase with a diameter of 3-5 nm. A close packing of the monocrystalline nanoparticles in the solid state is observed. However, in the dodecylamine sample, besides spherical particles, a fraction of the nanoparticles is elongated. The nanoparticles are readily resoluble in apolar solvents like hexane. Dynamic light scattering (DLS) and SAXS investigations of the solutions reveal that the nanoparticles are dissolved as singular particles. In the case of oleylamine-capped ZnS, a defined core-shell structure with a ZnS core with a diameter of 4 nm and an organic shell with a thickness of approximately 2 nm have been found. Dodecylamine-capped nanoparticles slightly tend to form agglomerates with a diameter of approximately 40 nm. PMID:22239986

  9. Condensin II Subunit dCAP-D3 Restricts Retrotransposon Mobilization in Drosophila Somatic Cells

    PubMed Central

    Schuster, Andrew T.; Sarvepalli, Kavitha; Murphy, Eain A.; Longworth, Michelle S.

    2013-01-01

    Retrotransposon sequences are positioned throughout the genome of almost every eukaryote that has been sequenced. As mobilization of these elements can have detrimental effects on the transcriptional regulation and stability of an organism's genome, most organisms have evolved mechanisms to repress their movement. Here, we identify a novel role for the Drosophila melanogaster Condensin II subunit, dCAP-D3 in preventing the mobilization of retrotransposons located in somatic cell euchromatin. dCAP-D3 regulates transcription of euchromatic gene clusters which contain or are proximal to retrotransposon sequence. ChIP experiments demonstrate that dCAP-D3 binds to these loci and is important for maintaining a repressed chromatin structure within the boundaries of the retrotransposon and for repressing retrotransposon transcription. We show that dCAP-D3 prevents accumulation of double stranded DNA breaks within retrotransposon sequence, and decreased dCAP-D3 levels leads to a precise loss of retrotransposon sequence at some dCAP-D3 regulated gene clusters and a gain of sequence elsewhere in the genome. Homologous chromosomes exhibit high levels of pairing in Drosophila somatic cells, and our FISH analyses demonstrate that retrotransposon-containing euchromatic loci are regions which are actually less paired than euchromatic regions devoid of retrotransposon sequences. Decreased dCAP-D3 expression increases pairing of homologous retrotransposon-containing loci in tissue culture cells. We propose that the combined effects of dCAP-D3 deficiency on double strand break levels, chromatin structure, transcription and pairing at retrotransposon-containing loci may lead to 1) higher levels of homologous recombination between repeats flanking retrotransposons in dCAP-D3 deficient cells and 2) increased retrotransposition. These findings identify a novel role for the anti-pairing activities of dCAP-D3/Condensin II and uncover a new way in which dCAP-D3/Condensin II influences local

  10. Condensin II subunit dCAP-D3 restricts retrotransposon mobilization in Drosophila somatic cells.

    PubMed

    Schuster, Andrew T; Sarvepalli, Kavitha; Murphy, Eain A; Longworth, Michelle S

    2013-10-01

    Retrotransposon sequences are positioned throughout the genome of almost every eukaryote that has been sequenced. As mobilization of these elements can have detrimental effects on the transcriptional regulation and stability of an organism's genome, most organisms have evolved mechanisms to repress their movement. Here, we identify a novel role for the Drosophila melanogaster Condensin II subunit, dCAP-D3 in preventing the mobilization of retrotransposons located in somatic cell euchromatin. dCAP-D3 regulates transcription of euchromatic gene clusters which contain or are proximal to retrotransposon sequence. ChIP experiments demonstrate that dCAP-D3 binds to these loci and is important for maintaining a repressed chromatin structure within the boundaries of the retrotransposon and for repressing retrotransposon transcription. We show that dCAP-D3 prevents accumulation of double stranded DNA breaks within retrotransposon sequence, and decreased dCAP-D3 levels leads to a precise loss of retrotransposon sequence at some dCAP-D3 regulated gene clusters and a gain of sequence elsewhere in the genome. Homologous chromosomes exhibit high levels of pairing in Drosophila somatic cells, and our FISH analyses demonstrate that retrotransposon-containing euchromatic loci are regions which are actually less paired than euchromatic regions devoid of retrotransposon sequences. Decreased dCAP-D3 expression increases pairing of homologous retrotransposon-containing loci in tissue culture cells. We propose that the combined effects of dCAP-D3 deficiency on double strand break levels, chromatin structure, transcription and pairing at retrotransposon-containing loci may lead to 1) higher levels of homologous recombination between repeats flanking retrotransposons in dCAP-D3 deficient cells and 2) increased retrotransposition. These findings identify a novel role for the anti-pairing activities of dCAP-D3/Condensin II and uncover a new way in which dCAP-D3/Condensin II influences local

  11. Helix Capping in RNA Structure

    PubMed Central

    Lee, Jung C.; Gutell, Robin R.

    2014-01-01

    Helices are an essential element in defining the three-dimensional architecture of structured RNAs. While internal basepairs in a canonical helix stack on both sides, the ends of the helix stack on only one side and are exposed to the loop side, thus susceptible to fraying unless they are protected. While coaxial stacking has long been known to stabilize helix ends by directly stacking two canonical helices coaxially, based on analysis of helix-loop junctions in RNA crystal structures, herein we describe helix capping, topological stacking of a helix end with a basepair or an unpaired nucleotide from the loop side, which in turn protects helix ends. Beyond the topological protection of helix ends against fraying, helix capping should confer greater stability onto the resulting composite helices. Our analysis also reveals that this general motif is associated with the formation of tertiary structure interactions. Greater knowledge about the dynamics at the helix-junctions in the secondary structure should enhance the prediction of RNA secondary structure with a richer set of energetic rules and help better understand the folding of a secondary structure into its three-dimensional structure. These together suggest that helix capping likely play a fundamental role in driving RNA folding. PMID:24691270

  12. Phytoremediation -- a practical capping alternative

    SciTech Connect

    Beath, J.M.; Peak, M.J.

    1997-12-31

    Much literature has been devoted recently to the use of various plant species for the uptake of heavy metals and organic contaminants. Other uses for plants as part of the remediation process are growing in perceived effectiveness. Consequently, this paper deals with two other equally important potential uses of plants to address environmental problems that are just now evolving to the field trial stage: the use of plants to remediate organic pollutants; and the use of plants to control the rainfall-driven leaching of contaminants and the subsequent delivery to underlying groundwater. The traditional Resource Conservation and Recovery Act (RCRA) approach to capping landfills will be contrasted with the potential benefits of using plants that can balance incoming rainfall with evapotranspiration, as well as plants which can act on organic constituents in soil or sludge by either uptake or by promoting microbial activity in soil. This paper compares traditional RCRA capping costs to those for a phytoremediation capping alternative, whose benefits include significantly lower implementation cost and continued remediation. This paper discusses important elements of a successful approach to phytoremediation including: species selection, implementation techniques, cost-efficient monitoring, regulatory aspects, project timing, and realistic expectations.

  13. Cassini CAPS and INMS Detection of Water Group Pick-Up Ions Near the Orbits of Saturn's Icy Moons Enceladus, Dione and Rhea

    NASA Astrophysics Data System (ADS)

    Tokar, R. L.; Bagenal, F.; Crary, F. J.; Omidi, N.; Paty, C. S.; Perry, M. E.; Thomsen, M. F.; Waite, J. H.; Wilson, R. J.

    2013-12-01

    In this study water group pick up ions near the orbits of Saturn's moons Enceladus, Dione, and Rhea are studied for all Cassini plasma spectrometer (CAPS) data since orbit insertion with comparisons made to Cassini ion and neutral mass spectrometer (INMS) observations in ion mode. In addition, in-situ CAPS pick-up ion phase space measurements during Cassini's Enceladus close encounters are compared with hybrid and multi-fluid simulations. The icy surfaces of Enceladus, Dione and Rhea, along with Enceladus' south polar plumes (~90% water vapor with a smaller admixture of CO2, CO, N2, and CH4), are sources of neutral H2O vapor. In the case of Enceladus, due to the plumes, the region of dense vapor is large whereas in the case of Dione and Rhea only a smaller exosphere near the surfaces exists. The dense bulk plasma in Saturn's inner magnetosphere (electrons, protons, water group ions) nearly co-rotates with Saturn near the orbits of these moons with speeds ~40 to 60 km/s while the neutral gas, both near the moons and in extended tori, moves at the slower gravitational orbital speeds. This relative speed leads to a characteristic 'pick-up' velocity space signature for these ions near their source region (before assimilation into the core ion population) and since arriving at Saturn CAPS has detected O+, OH+, H2O+ and H3O+ with these fresh 'pick-up' signatures. In addition, previous studies have shown that the Cassini INMS detected H3O+ near Enceladus with similar phase space density and simultaneous with the CAPS observations. These studies are extended, using the full CAPS/INMS data sets and the highest fidelity simulations.

  14. Nanosized (mu12-Pt)Pd164-xPtx(CO)72(PPh3)20 (x approximately 7) containing Pt-centered four-shell 165-atom Pd-Pt core with unprecedented intershell bridging carbonyl ligands: comparative analysis of icosahedral shell-growth patterns with geometrically related Pd145(CO)x(PEt3)30 (x approximately 60) containing capped three-shell Pd145 core.

    PubMed

    Mednikov, Evgueni G; Jewell, Matthew C; Dahl, Lawrence F

    2007-09-19

    Presented herein are the preparation and crystallographic/microanalytical/magnetic/spectroscopic characterization of the Pt-centered four-shell 165-atom Pd-Pt cluster, (mu(12)-Pt)Pd(164-x)Pt(x)(CO)(72)(PPh(3))(20) (x approximately 7), 1, that replaces the geometrically related capped three-shell icosahedral Pd(145) cluster, Pd(145)(CO)(x)(PEt(3))(30) (x approximately 60), 2, as the largest crystallographically determined discrete transition metal cluster with direct metal-metal bonding. A detailed comparison of their shell-growth patterns gives rise to important stereochemical implications concerning completely unexpected structural dissimilarities as well as similarities and provides new insight concerning possible synthetic approaches for generation of multi-shell metal clusters. 1 was reproducibly prepared in small yields (<10%) from the reaction of Pd(10)(CO)(12)(PPh(3))(6) with Pt(CO)(2)(PPh(3))(2). Its 165-atom metal-core geometry and 20 PPh(3) and 72 CO ligands were established from a low-temperature (100 K) CCD X-ray diffraction study. The well-determined crystal structure is attributed largely to 1 possessing cubic T(h) (2/m3) site symmetry, which is the highest crystallographic subgroup of the noncrystallographic pseudo-icosahedral I(h) (2/m35) symmetry. The "full" four-shell Pd-Pt anatomy of 1 consists of: (a) shell 1 with the centered (mu(12)-Pt) atom encapsulated by the 12-atom icosahedral Pt(x)Pd(12-x) cage, x = 1.2(3); (b) shell 2 with the 42-atom nu(2) icosahedral Pt(x)Pd(42-x) cage, x = 3.5(5); (c) shell 3 with the anti-Mackay 60-atom semi-regular rhombicosidodecahedral Pt(x)Pd(60-x) cage, x = 2.2(6); (d) shell 4 with the 50-atom nu(2) pentagonal dodecahedral Pd(50) cage. The total number of crystallographically estimated Pt atoms, 8 +/- 3, which was obtained from least-squares (Pt(x)/Pd(1-x))-occupancy analysis of the X-ray data that conclusively revealed the central atom to be pure Pt (occupancy factor, x = 1.00(3)), is fortuitously in agreement

  15. Identification and characterization of a cDNA encoding mouse CAP: a homolog of the yeast adenylyl cyclase associated protein.

    PubMed

    Vojtek, A B; Cooper, J A

    1993-07-01

    CAP, an adenylyl cyclase associated protein, is present in Saccharomyces cerevisiae and Schizosaccharomyces pombe. In both organisms, CAP is bifunctional: the N-terminal domain binds to adenylyl cyclase, thereby enabling adenylyl cyclase to respond appropriately to upstream regulatory signals, such as RAS in S. cerevisiae; the C-terminal domain is required for cellular morphogenesis. Here, we describe the isolation of a cDNA encoding a CAP homolog from a higher eukaryote. The mouse CAP cDNA contains an open reading frame capable of encoding a 474 amino acid protein. The protein encoded by the mouse CAP cDNA shows extensive homology to the yeast CAP proteins, particularly in the central poly-proline rich region and in the C-terminal domain. By northern analysis, the CAP message appears to be ubiquitous, but not uniform. By indirect immunofluorescence, ectopically expressed mouse CAP protein is found in the cytoplasm of fibroblasts and, in migrating cells, at the leading edge. Expression of the mouse CAP cDNA in S. cerevisiae complements defects associated with loss of the yeast CAP carboxy-terminal domain. Hence, the function of the CAP carboxy-terminal domain has been conserved from yeast to mouse.

  16. A late Holocene record of trace metal deposition in lake sediments near Quelccaya Ice Cap, Peru

    NASA Astrophysics Data System (ADS)

    Beal, S. A.; Kelly, M. A.; Jackson, B. P.; Osterberg, E. C.; Stroup, J. S.; Baker, R. A.

    2010-12-01

    Records of atmospheric metal deposition have been used extensively in the Northern Hemisphere to examine historical events ranging from the evolution of ancient metallurgy to climatic change. Establishing such a record in tropical South America is pertinent due to ongoing questions about the metallurgical history of pre-colonial Andean civilizations, recent atmospheric pollution levels, and late Holocene climate variability. Here we present a late Holocene record of the Ag, As, Cd, Co, Cu, Hg, Ni, Pb, Sr, Zn, and Pb isotopic compositions of atmospheric deposition from three 1.5 m-long lake cores and one 5 m-long bog core recovered near Quelccaya Ice Cap (13.9 °S), in the southeastern Peruvian Andes. The bog core, representing deposition from the present to at least 2415 yr BP, records relatively stable concentrations of As, Co, Cu, Hg, Ni, Pb, Sr, and Zn between 2415 (±78) and 916 (±29) yr BP. However, Ag and Cd exhibit brief gradual enrichments over background levels by factors of 6 and 11, respectively, shortly after 2415 (±78) yr BP as a possible result of ancient metallurgy. Sometime following the 916 (±29) yr BP date, Ag, As, Cd, Cu, Hg, Ni, Pb, and Sr abruptly become enriched by factors of 10, 37, 11, 11, 47, 6, 16, and 24, respectively, possibly from anthropogenic sources and/or the 1600 AD eruption of Huaynaputina in southern Peru. These enrichments are concurrent with a shift in 206Pb/207Pb to 1.182 from background levels of 1.213 (±0.002, n=20). A subsequent quiescent period in metal concentrations is marked by a brief return to background 206Pb/207Pb values, followed by erratic 206Pb/207Pb values yet decreased metal concentrations in the most recent sediments. Only Hg is enriched over background levels, by a factor of 3, in the most recent sediment. Forthcoming higher-resolution data from the three lake cores will utilize pre-industrial lead isotope ratios and Ti, Zr, and REE fluxes to examine past variability of the El Niño-Southern Oscillation

  17. Relationship between cap structure and energy gap in capped carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Ono, Shota; Tanikawa, Kousei; Kuwahara, Riichi; Ohno, Kaoru

    2016-07-01

    Revealing a universal relation between geometrical structures and electronic properties of capped carbon nanotubes (CNTs) is one of the current objectives in nanocarbon community. Here, we investigate the local curvature of capped CNTs and define the cap region by a crossover behavior of the curvature energy versus the number of carbon atoms integrated from the tip to the tube region. Clear correlations among the energy gap of the cap localized states, the curvature energy, the number of carbon atoms in the cap region, and the number of specific carbon clusters are observed. The present analysis opens the way to understand the cap states.

  18. Relationship between cap structure and energy gap in capped carbon nanotubes.

    PubMed

    Ono, Shota; Tanikawa, Kousei; Kuwahara, Riichi; Ohno, Kaoru

    2016-07-14

    Revealing a universal relation between geometrical structures and electronic properties of capped carbon nanotubes (CNTs) is one of the current objectives in nanocarbon community. Here, we investigate the local curvature of capped CNTs and define the cap region by a crossover behavior of the curvature energy versus the number of carbon atoms integrated from the tip to the tube region. Clear correlations among the energy gap of the cap localized states, the curvature energy, the number of carbon atoms in the cap region, and the number of specific carbon clusters are observed. The present analysis opens the way to understand the cap states. PMID:27421422

  19. Crystal chemistry of layered structures formed by linear rigid silyl-capped molecules

    PubMed Central

    Lumpi, Daniel; Kautny, Paul; Stöger, Berthold; Fröhlich, Johannes

    2015-01-01

    The crystallization behavior of methylthio- or methylsulfonyl-containing spacer extended Z,Z-bis-ene–yne molecules capped with trimethylsilyl groups obtained by (tandem) thiophene ring fragmentation and of two non-spacer extended analogs were investigated. The rigid and linear molecules generally crystallized in layers whereby the flexibility of the layer interfaces formed by the silyl groups leads to a remarkably rich crystal chemistry. The molecules with benzene and thiophene spacers both crystallized with C2/c symmetry and can be considered as merotypes. Increasing the steric bulk of the core by introduction of ethylenedioxythiophene (EDOT) gave a structure incommensurately modulated in the [010] direction. Further increase of steric demand in the case of a dimethoxythiophene restored periodicity along [010] but resulted in a doubling of the c vector. Two different polytypes were observed, which feature geometrically different layer interfaces (non-OD, order–disorder, polytypes), one with a high stacking fault probability. Oxidation of the methylthio groups of the benzene-based molecule to methylsulfonyl groups led to three polymorphs (two temperature-dependent), which were analyzed by Hirshfeld surface d e/d i fingerprint plots. The analogously oxidized EDOT-based molecule crystallized as systematic twins owing to its OD polytypism. Shortening of the backbone by removal of the aryl core resulted in an enantiomorphic structure and a further shortening by removal of a methylthio-ene fragment again in a systematically twinned OD polytype. PMID:26306200

  20. CAP defines a second signalling pathway required for insulin-stimulated glucose transport

    NASA Astrophysics Data System (ADS)

    Baumann, Christian A.; Ribon, Vered; Kanzaki, Makoto; Thurmond, Debbie C.; Mora, Silvia; Shigematsu, Satoshi; Bickel, Perry E.; Pessin, Jeffrey E.; Saltiel, Alan R.

    2000-09-01

    Insulin stimulates the transport of glucose into fat and muscle cells. Although the precise molecular mechanisms involved in this process remain uncertain, insulin initiates its actions by binding to its tyrosine kinase receptor, leading to the phosphorylation of intracellular substrates. One such substrate is the Cbl protooncogene product. Cbl is recruited to the insulin receptor by interaction with the adapter protein CAP, through one of three adjacent SH3 domains in the carboxy terminus of CAP. Upon phosphorylation of Cbl, the CAP-Cbl complex dissociates from the insulin receptor and moves to a caveolin-enriched, triton-insoluble membrane fraction. Here, to identify a molecular mechanism underlying this subcellular redistribution, we screened a yeast two-hybrid library using the amino-terminal region of CAP and identified the caveolar protein flotillin. Flotillin forms a ternary complex with CAP and Cbl, directing the localization of the CAP-Cbl complex to a lipid raft subdomain of the plasma membrane. Expression of the N-terminal domain of CAP in 3T3-L1 adipocytes blocks the stimulation of glucose transport by insulin, without affecting signalling events that depend on phosphatidylinositol-3-OH kinase. Thus, localization of the Cbl-CAP complex to lipid rafts generates a pathway that is crucial in the regulation of glucose uptake.

  1. Mountain Glaciers and Ice Caps

    USGS Publications Warehouse

    Ananichheva, Maria; Arendt, Anthony; Hagen, Jon-Ove; Hock, Regine; Josberger, Edward G.; Moore, R. Dan; Pfeffer, William Tad; Wolken, Gabriel J.

    2011-01-01

    Projections of future rates of mass loss from mountain glaciers and ice caps in the Arctic focus primarily on projections of changes in the surface mass balance. Current models are not yet capable of making realistic forecasts of changes in losses by calving. Surface mass balance models are forced with downscaled output from climate models driven by forcing scenarios that make assumptions about the future rate of growth of atmospheric greenhouse gas concentrations. Thus, mass loss projections vary considerably, depending on the forcing scenario used and the climate model from which climate projections are derived. A new study in which a surface mass balance model is driven by output from ten general circulation models (GCMs) forced by the IPCC (Intergovernmental Panel on Climate Change) A1B emissions scenario yields estimates of total mass loss of between 51 and 136 mm sea-level equivalent (SLE) (or 13% to 36% of current glacier volume) by 2100. This implies that there will still be substantial glacier mass in the Arctic in 2100 and that Arctic mountain glaciers and ice caps will continue to influence global sea-level change well into the 22nd century.

  2. Composite Cores

    NASA Technical Reports Server (NTRS)

    1990-01-01

    Spang & Company's new configuration of converter transformer cores is a composite of gapped and ungapped cores assembled together in concentric relationship. The net effect of the composite design is to combine the protection from saturation offered by the gapped core with the lower magnetizing requirement of the ungapped core. The uncut core functions under normal operating conditions and the cut core takes over during abnormal operation to prevent power surges and their potentially destructive effect on transistors. Principal customers are aerospace and defense manufacturers. Cores also have applicability in commercial products where precise power regulation is required, as in the power supplies for large mainframe computers.

  3. Where Will LEAD Lead?

    ERIC Educational Resources Information Center

    Wildman, Louis

    After setting forth eight assumptions concerning the education of educational administrators, findings about the Leadership in Educational Administration Development (LEAD) program are discussed. The analysis is based on the first-year applications, telephone conversations with staff at a majority of the project sites, and additional material…

  4. Structural characterisation of alkyl amine-capped zinc sulphide nanoparticles

    PubMed Central

    Kremser, Gabriele; Rath, Thomas; Kunert, Birgit; Edler, Michael; Fritz-Popovski, Gerhard; Resel, Roland; Letofsky-Papst, Ilse; Grogger, Werner; Trimmel, Gregor

    2012-01-01

    Nanoparticles capped with amine ligands with different steric properties, dodecylamine and oleylamine, respectively, are investigated in the solid state as well as in solution. A combined X-ray diffraction, small angle X-ray scattering and electron microscopy investigation showed that the nanoparticles exhibit the sphalerite modification of ZnS as crystal phase with a diameter of 3–5 nm. A close packing of the monocrystalline nanoparticles in the solid state is observed. However, in the dodecylamine sample, besides spherical particles, a fraction of the nanoparticles is elongated. The nanoparticles are readily resoluble in apolar solvents like hexane. Dynamic light scattering (DLS) and SAXS investigations of the solutions reveal that the nanoparticles are dissolved as singular particles. In the case of oleylamine-capped ZnS, a defined core–shell structure with a ZnS core with a diameter of 4 nm and an organic shell with a thickness of approximately 2 nm have been found. Dodecylamine-capped nanoparticles slightly tend to form agglomerates with a diameter of approximately 40 nm. PMID:22239986

  5. Structure-activity relationships for in vitro diuretic activity of CAP2b in the housefly

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A series of truncated and Ala-replacement analogs of the peptide Manse-CAP2b (pELYAFPRV-NH2) were assayed for diuretic activity on Malpighian tubules of the housefly Musca domestica. The C-terminal hexapeptide proved to be the active core, the minimum sequence required to retain significant diureti...

  6. LEAD IN CANDLE EMISSIONS

    EPA Science Inventory

    The candle-using public should be made aware that the core of candle wicks may contain lead. Used as a stiffening agent to keep the wick out of the molten wax, lead can be emitted as particulate to the air and then deposited on indoor surfaces. To define the problem, 100 sets of ...

  7. LEADING WITH LEADING INDICATORS

    SciTech Connect

    PREVETTE, S.S.

    2005-01-27

    This paper documents Fluor Hanford's use of Leading Indicators, management leadership, and statistical methodology in order to improve safe performance of work. By applying these methods, Fluor Hanford achieved a significant reduction in injury rates in 2003 and 2004, and the improvement continues today. The integration of data, leadership, and teamwork pays off with improved safety performance and credibility with the customer. The use of Statistical Process Control, Pareto Charts, and Systems Thinking and their effect on management decisions and employee involvement are discussed. Included are practical examples of choosing leading indicators. A statistically based color coded dashboard presentation system methodology is provided. These tools, management theories and methods, coupled with involved leadership and employee efforts, directly led to significant improvements in worker safety and health, and environmental protection and restoration at one of the nation's largest nuclear cleanup sites.

  8. CAPS Capsule. Volume 5, Number 1.

    ERIC Educational Resources Information Center

    Walz, Garry, Ed.; And Others

    Published 3 times yearly by the ERIC Clearinghouse on Counseling and Personnel Services, CAPS Capsule acquaints the reader with recent projects, meetings, publications and materials which are of interest to those in the helping professions. This issue introduces several new publications offered by CAPS under the name, "The Counselor's S x-Pack."…

  9. 31 CFR 50.15 - Cap disclosure.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 31 Money and Finance: Treasury 1 2013-07-01 2013-07-01 false Cap disclosure. 50.15 Section 50.15 Money and Finance: Treasury Office of the Secretary of the Treasury TERRORISM RISK INSURANCE PROGRAM Disclosures as Conditions for Federal Payment § 50.15 Cap disclosure. (a) General. Under section 103(e)(2)...

  10. 31 CFR 50.15 - Cap disclosure.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 31 Money and Finance: Treasury 1 2011-07-01 2011-07-01 false Cap disclosure. 50.15 Section 50.15 Money and Finance: Treasury Office of the Secretary of the Treasury TERRORISM RISK INSURANCE PROGRAM Disclosures as Conditions for Federal Payment § 50.15 Cap disclosure. (a) General. Under section 103(e)(2)...

  11. 31 CFR 50.15 - Cap disclosure.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 31 Money and Finance: Treasury 1 2014-07-01 2014-07-01 false Cap disclosure. 50.15 Section 50.15 Money and Finance: Treasury Office of the Secretary of the Treasury TERRORISM RISK INSURANCE PROGRAM Disclosures as Conditions for Federal Payment § 50.15 Cap disclosure. (a) General. Under section 103(e)(2)...

  12. 31 CFR 50.15 - Cap disclosure.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 31 Money and Finance: Treasury 1 2012-07-01 2012-07-01 false Cap disclosure. 50.15 Section 50.15 Money and Finance: Treasury Office of the Secretary of the Treasury TERRORISM RISK INSURANCE PROGRAM Disclosures as Conditions for Federal Payment § 50.15 Cap disclosure. (a) General. Under section 103(e)(2)...

  13. 31 CFR 50.15 - Cap disclosure.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 31 Money and Finance: Treasury 1 2010-07-01 2010-07-01 false Cap disclosure. 50.15 Section 50.15 Money and Finance: Treasury Office of the Secretary of the Treasury TERRORISM RISK INSURANCE PROGRAM Disclosures as Conditions for Federal Payment § 50.15 Cap disclosure. (a) General. Under section 103(e)(2)...

  14. Seasonal Changes in Mars' North Polar Ice Cap

    NASA Technical Reports Server (NTRS)

    1997-01-01

    , noted previously by HST in 1995 and Mariner 9 in 1972; this may be due to topography, which isn't well known, or to wave structure in the circulation. This map was assembled from WFPC2 images obtained between Dec. 30, 1996 and Jan. 4, 1997.

    March 30, 1997 (early summer): The cap has fully retreated to its remnant core of water-ice. This residual cap is actually almost cut into two by a large, horn-shaped canyon called Chasma Borealis which is cut deeply into the polar terrain. The HST images also reveal a curious layered terrain which is evidence of past climatic changes on Mars. The sublimation of all of the carbon dioxide has exposed the ring of dark sand dunes which encircle the North Polar Cap. Outliers of ice persist south of the polar sand sea (between the 3 o'clock and 9 o'clock positions). The bright circular features at 3, 6, and 9 o'clock are ice-filled craters.

    All images were taken with the Wide Field and Planetary Camera 2. The color is constructed from images taken in red (673 nm) , blue (410 nm) and green (502 nm) light. The resolution at the North Pole ranges from about 115 km/pixel in October '96 to about 45 km/pixel in March '97.

    This image and other images and data received from the Hubble Space Telescope are posted on the World Wide Web on the Space Telescope Science Institute home page at URL http://oposite.stsci.edu/pubinfo/

  15. The small ice cap instability in diffusive climate models

    NASA Technical Reports Server (NTRS)

    North, G. R.

    1984-01-01

    Simple climate models which invoke diffusive heat transport and ice cap albedo feedback have equilibrium solutions with no stable ice cap smaller than a radius of about 20 deg on a great circle. Attention is presently given to a solution of this phenomenon which is physically appealing. The ice-free solution has a thermal minimum, and if the minimum temperature is just above the critical value for ice formation, then the artificial addition of a patch of ice leads to a widespread depression of the temperature below the critical freezing temperature. A second stable solution will then exist whose spatial extent is determined by the range of the influence function of a point sink of heat, due to the albedo shift in the patch.

  16. Ground penetrating radar and direct current resistivity evaluation of the desiccation test cap, Savannah River Site

    SciTech Connect

    Wyatt, D.E.; Cumbest, R.J.

    1996-04-01

    The Savannah River Site (SRS) has a variety of waste units that may be temporarily or permanently stabilized by closure using an impermeable cover to prevent groundwater infiltration. The placement of an engineered kaolin clay layer over a waste unit is an accepted and economical technique for providing an impermeable cover but the long term stability and integrity of the clay in non-arid conditions is unknown. A simulated kaolin cap has been constructed at the SRA adjacent to the Burial Ground Complex. The cap is designed to evaluate the effects of desiccation on clay integrity, therefore half of the cap is covered with native soil to prevent drying, while the remainder of the cap is exposed. Measurements of the continuing impermeability of a clay cap are difficult because intrusive techniques may locally compromise the structure. Point measurements made to evaluate clay integrity, such as those from grid sampling or coring and made through a soil cover, may miss cracks, joints or fissures, and may not allow for mapping of the lateral extent of elongate features. Because of these problems, a non-invasive technique is needed to map clay integrity, below a soil or vegetation cover, which is capable of moderate to rapid investigation speeds. Two non-intrusive geophysical techniques, direct current resistivity and ground penetrating radar (GPR), have been successful at the SRS in geologically mapping shallow subsurface clay layers. The applicability of each technique in detecting the clay layer in the desiccation test cap and associated anomalies was investigated.

  17. Origin of interfacial perpendicular magnetic anisotropy in MgO/CoFe/metallic capping layer structures

    PubMed Central

    Peng, Shouzhong; Wang, Mengxing; Yang, Hongxin; Zeng, Lang; Nan, Jiang; Zhou, Jiaqi; Zhang, Youguang; Hallal, Ali; Chshiev, Mairbek; Wang, Kang L.; Zhang, Qianfan; Zhao, Weisheng

    2015-01-01

    Spin-transfer-torque magnetic random access memory (STT-MRAM) attracts extensive attentions due to its non-volatility, high density and low power consumption. The core device in STT-MRAM is CoFeB/MgO-based magnetic tunnel junction (MTJ), which possesses a high tunnel magnetoresistance ratio as well as a large value of perpendicular magnetic anisotropy (PMA). It has been experimentally proven that a capping layer coating on CoFeB layer is essential to obtain a strong PMA. However, the physical mechanism of such effect remains unclear. In this paper, we investigate the origin of the PMA in MgO/CoFe/metallic capping layer structures by using a first-principles computation scheme. The trend of PMA variation with different capping materials agrees well with experimental results. We find that interfacial PMA in the three-layer structures comes from both the MgO/CoFe and CoFe/capping layer interfaces, which can be analyzed separately. Furthermore, the PMAs in the CoFe/capping layer interfaces are analyzed through resolving the magnetic anisotropy energy by layer and orbital. The variation of PMA with different capping materials is attributed to the different hybridizations of both d and p orbitals via spin-orbit coupling. This work can significantly benefit the research and development of nanoscale STT-MRAM. PMID:26656721

  18. Mars seasonal polar caps as a test of the equivalence principle

    NASA Astrophysics Data System (ADS)

    Rubincam, David Parry

    2011-08-01

    The seasonal polar caps of Mars can be used to test the equivalence principle in general relativity. The north and south caps, which are composed of carbon dioxide, wax and wane with the seasons. If the ratio of the inertial (passive) to gravitational (active) masses of the caps differs from the same ratio for the rest of Mars, then the equivalence principle fails, Newton’s third law fails, and the caps will pull Mars one way and then the other with a force aligned with the planet’s spin axis. This leads to a secular change in Mars’s along-track position in its orbit about the Sun, and to a secular change in the orbit’s semimajor axis. The caps are a poor Eötvös test of the equivalence principle, being 4 orders-of-magnitude weaker than laboratory tests and 7 orders-of-magnitude weaker than that found by lunar laser ranging; the reason is the small mass of the caps compared to Mars as a whole. The principal virtue of using Mars is that the caps contain carbon, an element not normally considered in such experiments. The Earth with its seasonal snow cover can also be used for a similar test.

  19. Mars Seasonal Polar Caps as a Test of the Equivalence Principle

    NASA Technical Reports Server (NTRS)

    Rubincam, Daivd Parry

    2011-01-01

    The seasonal polar caps of Mars can be used to test the equivalence principle in general relativity. The north and south caps, which are composed of carbon dioxide, wax and wane with the seasons. If the ratio of the inertial to gravitational masses of the caps differs from the same ratio for the rest of Mars, then the equivalence principle fails, Newton's third law fails, and the caps will pull Mars one way and then the other with a force aligned with the planet's spin axis. This leads to a secular change in Mars's along-track position in its orbit about the Sun, and to a secular change in the orbit's semimajor axis. The caps are a poor E6tv6s test of the equivalence principle, being 4 orders-of-magnitude weaker than laboratory tests and 7 orders-of-magnitude weaker than that found by lunar laser ranging; the reason is the small mass of the caps compared to Mars as a whole. The principal virtue of using Mars is that the caps contain carbon, an element not normally considered in such experiments. The Earth with its seasonal snow cover can also be used for a similar test.

  20. Innovation under cap-and-trade programs

    PubMed Central

    Taylor, Margaret R.

    2012-01-01

    Policies incentivizing the private sector to reach its innovative potential in “clean” technologies are likely to play a key role in achieving climate stabilization. This article explores the relationship between innovation and cap-and-trade programs (CTPs)—the world's most prominent climate policy instrument—through empirical evidence drawn from successful CTPs for sulfur dioxide and nitrogen oxide control. The article shows that before trading began for these CTPs, analysts overestimated the value of allowances in a pattern suggestive of the frequent a priori overestimation of the compliance costs of regulation. When lower-than-expected allowance prices were observed, in part because of the unexpected range of abatement approaches used in the lead-up to trading, emissions sources chose to bank allowances in significant numbers and reassess abatement approaches going forward. In addition, commercially oriented inventive activity declined for emissions-reducing technologies with a wide range of costs and technical characteristics, dropping from peaks before the establishment of CTPs to nadirs a few years into trading. This finding is consistent with innovators deciding during trading that their research and development investments should be reduced, based on assessments of future market conditions under the relevant CTPs. The article concludes with a discussion of the results and their implications for innovation and climate policy. PMID:22411797

  1. The role of rotation and polar-cap currents on pulsar radio emission and polarization

    SciTech Connect

    Kumar, D.; Gangadhara, R. T. E-mail: ganga@iiap.res.in

    2013-06-01

    Perturbations such as rotation and polar-cap current (PC-current) have been believed to greatly affect the pulsar radio emission and polarization. The two effects have not been considered simultaneously in the literature; each one of these has been considered separately, and a picture has been deduced by simply superposing them, but such an approach can lead to spurious results. Hence, by considering pulsar rotation and PC-current perturbations together instead of one at a time, we have developed a single particle curvature radiation model, which is expected to be much more realistic. By simulating a set of typical pulse profiles, we have made an attempt to explain most of the observational results of pulsar radio emission and polarization. The model predicts that due to the perturbations the leading side component can become either stronger or weaker than the corresponding trailing one in any given cone, depending on the passage of the sight line and modulation (nonuniform source distribution). Further, we find that the phase delay of the polarization angle inflection point with respect to the core component greatly depends on the viewing geometry. The correlation between the sign reversal of circular polarization and the polarization angle swing in the case of core-dominated pulsars becomes obscure once the perturbations and modulation become significant. However, the correlation between the negative circular polarization and the increasing polarization angle and vice versa is very clear in the case of conal-double pulsars. The 'kinky'-type distortions in polarization angle swing could be due to the incoherent superposition of modulated emission in the presence of strong perturbations.

  2. Effect of tissue properties, shape and orientation of microcalcifications on vulnerable cap stability using different hyperelastic constitutive models

    PubMed Central

    Cardoso, Luis; Kelly-Arnold, Adreanne; Maldonado, Natalia; Laudier, Damien; Weinbaum, Sheldon

    2014-01-01

    Approximately half of all cardiovascular deaths associated with acute coronary syndrome occur when the thin fibrous cap tissue overlying the necrotic core in a coronary vessel is torn, ripped or fissured under the action of high blood pressure. From a biomechanics point of view, the rupture of an atheroma is due to increased mechanical stresses in the lesion, in which the ultimate stress (i.e. peak circumferential stress (PCS) at failure) of the tissue is exceeded. Several factors including the cap thickness, morphology, residual stresses and tissue composition of the atheroma have been shown to affect the PCS. Also important, we recently demonstrated that microcalcifications (µCalcs) > 5 µm are a common feature in human atheroma caps, which behave as local stress concentrators, increasing the local tissue stress by at least a factor of two surpassing the ultimate stress threshold for cap tissue rupture. In the present study, we used both idealized µCalcs with spherical shape and actual µCalcs from human coronary atherosclerotic caps, to determine their effect on increasing the circumferential stress in the fibroatheroma cap using different hyperelastic constitutive models. We have found that the stress concentration factor (SCF) produced by µCalcs in the fibroatheroma cap is affected by the material tissue properties, µCalcs spacing, aspect ratio and their alignment relative to the tensile axis of the cap. PMID:24503048

  3. Effect of tissue properties, shape and orientation of microcalcifications on vulnerable cap stability using different hyperelastic constitutive models.

    PubMed

    Cardoso, Luis; Kelly-Arnold, Adreanne; Maldonado, Natalia; Laudier, Damien; Weinbaum, Sheldon

    2014-03-01

    Approximately half of all cardiovascular deaths associated with acute coronary syndrome occur when the thin fibrous cap tissue overlying the necrotic core in a coronary vessel is torn, ripped or fissured under the action of high blood pressure. From a biomechanics point of view, the rupture of an atheroma is due to increased mechanical stresses in the lesion, in which the ultimate stress (i.e. peak circumferential stress (PCS) at failure) of the tissue is exceeded. Several factors including the cap thickness, morphology, residual stresses and tissue composition of the atheroma have been shown to affect the PCS. Also important, we recently demonstrated that microcalcifications (μCalcs>5 µm are a common feature in human atheroma caps, which behave as local stress concentrators, increasing the local tissue stress by at least a factor of two surpassing the ultimate stress threshold for cap tissue rupture. In the present study, we used both idealized µCalcs with spherical shape and actual µCalcs from human coronary atherosclerotic caps, to determine their effect on increasing the circumferential stress in the fibroatheroma cap using different hyperelastic constitutive models. We have found that the stress concentration factor (SCF) produced by μCalcs in the fibroatheroma cap is affected by the material tissue properties, μCalcs spacing, aspect ratio and their alignment relative to the tensile axis of the cap. PMID:24503048

  4. CAPS and INMS Major Accomplishments

    NASA Astrophysics Data System (ADS)

    Waite, J. Hunter

    2014-05-01

    The Cassini-Huygens Ion Neutral Mass Spectrometer (Cassini INMS) and the Cassini Plasma Spectrometer (CAPS) have provided "discovery" science at Titan, Enceladus, Rhea/Dione, and throughout the magnetosphere of Saturn during the course of the mission. In this talk we will review some of the major scientific achievements: 1) the discovery of an extremely complex ion neutral organic chemistry in Titan's upper atmosphere that forms the building blocks for aerosol processes below, 2) the discovery of gases and grains emanating from Enceladus' cryo-geysers that tell us about chemical processes in an interior sea, 3) the first direct compositional measurements of sputtered icy moon surfaces, 4) the clearest example to date of the complex plasma interchange processes that occur in rapidly rotating magnetospheres of gas giants, initiating global dynamic processes that enable Saturn to shed the plasma from Enceladus' plume, and complete with a myriad of longitudinal and solar local-time variations, and 5) the dominance of Enceladus water outgassing as a source of magnetospheric plasma that stretches out to Titan and provides oxygen that can convert Titan's rich nitrile populations into amino acids.

  5. The pharmaceutical vial capping process: Container closure systems, capping equipment, regulatory framework, and seal quality tests.

    PubMed

    Mathaes, Roman; Mahler, Hanns-Christian; Buettiker, Jean-Pierre; Roehl, Holger; Lam, Philippe; Brown, Helen; Luemkemann, Joerg; Adler, Michael; Huwyler, Joerg; Streubel, Alexander; Mohl, Silke

    2016-02-01

    Parenteral drug products are protected by appropriate primary packaging to protect against environmental factors, including potential microbial contamination during shelf life duration. The most commonly used CCS configuration for parenteral drug products is the glass vial, sealed with a rubber stopper and an aluminum crimp cap. In combination with an adequately designed and controlled aseptic fill/finish processes, a well-designed and characterized capping process is indispensable to ensure product quality and integrity and to minimize rejections during the manufacturing process. In this review, the health authority requirements and expectations related to container closure system quality and container closure integrity are summarized. The pharmaceutical vial, the rubber stopper, and the crimp cap are described. Different capping techniques are critically compared: The most common capping equipment with a rotating capping plate produces the lowest amount of particle. The strength and challenges of methods to control the capping process are discussed. The residual seal force method can characterize the capping process independent of the used capping equipment or CCS. We analyze the root causes of several cosmetic defects associated with the vial capping process.

  6. Lead Poisoning

    MedlinePlus

    ... Experiments Stories Lessons Topics Games Activities Lessons MENU Lead Poisoning Kids Homepage Topics Pollution Lead Poisoning What is ... you can avoid contact with it! Sources of Lead Poisoning HOUSE PAINTS: Before1950, lead-based paint was used ...

  7. Lead Test

    MedlinePlus

    ... to determine lead sources, educating family members about lead poisoning , and instituting follow-up testing to monitor the ... high levels of lead, see the article on Lead Poisoning . The Occupational Safety and Health Administration (OSHA) has ...

  8. Lead Poisoning

    MedlinePlus

    Lead Poisoning What is it and who is affected? Lead is a highly toxic substance, exposure to which ... and children can suffer from the effects of lead poisoning, but childhood lead poisoning is much more frequent. ...

  9. Ice-core evidence of abrupt climate changes

    PubMed Central

    Alley, Richard B.

    2000-01-01

    Ice-core records show that climate changes in the past have been large, rapid, and synchronous over broad areas extending into low latitudes, with less variability over historical times. These ice-core records come from high mountain glaciers and the polar regions, including small ice caps and the large ice sheets of Greenland and Antarctica. PMID:10677460

  10. Ice-core evidence of abrupt climate changes.

    PubMed

    Alley, R B

    2000-02-15

    Ice-core records show that climate changes in the past have been large, rapid, and synchronous over broad areas extending into low latitudes, with less variability over historical times. These ice-core records come from high mountain glaciers and the polar regions, including small ice caps and the large ice sheets of Greenland and Antarctica.

  11. cap alpha. -Methyl-p-tyrosine shifts circadian temperature rhythms

    SciTech Connect

    Cahill, A.L.; Ehret, C.F.

    1982-09-01

    ..cap alpha..-Methyl-p-tyrosine shifts the acrophase (time of highest temperature) of the circadian temperature rhythm of the rat to earlier or later times of day depending on the phase of the cicadian cycle at which the drug is administered. When ..cap alpha..-methyl-p-tyrosine methyl ester HCl is injected intraperitoneally at a dose of 100 mg/kg late in the projected 8-h light phase, the acrophase of the intraperitoneal temperature rhythm is delayed by up to 3 h.However, when the same dose of drug is given 9-10 h into the projected 16-h dark phase of the daily cycle, the acrophase of the temperature rhythm occurs about 2 h earlier than expected. The times of ..cap alpha..-methyl-p-tyrosine administration leading to maximal phase delays or advances are correlated with the times of minimal and maximal turnover of norepinephrine in the hypothalamus. These results suggest that changing rates of norepinephrine turnover in the hypothalamus may regulate the circadian temperature rhythm in rats. The results also emphasize the fact that the effects of drugs may vary as a function of the time of administration. This fact must be taken into account in pharmacologic testing.

  12. The cytotoxicity of NiO nanoparticle with borate capping.

    PubMed

    Liu, Zunjing; Wang, Yongjing; Pan, Danmei; Chen, Zhi; Pan, Xiaohong; Wang, Yonghao; Lin, Zhang

    2011-11-01

    The impact of surface capping on cytotoxicity of NiO nanoparticle was investigated with Escherichia coil (E.coli) in this work. The NiO nanoparticle and NiO nanoparticle capped by borate (denoted as NiO-borate) were synthesized by hydrothermal method. The average size of both nanoparticles is about 4.0 nm. The plate experiments demonstrated that NiO-borate nanoparticles show lower cytotoxicity than NiO nanopaticles. Further spectrophotometric analysis revealed that the concentration of both extracellular and intercellular Ni2+ in NiO-borate system were lower than that of uncapped one. Intracellular ICP-AES analysis also showed the concentration of Ni element was higher than Ni2+, suggesting the NiO nanoparticles might penetrate into the cellular interior. Comprehensive AFM, SEM and TEM observation illustrated both NiO-borate and NiO nanoparticles lead to the collapse of cellular body, the convex on the cell wall and the damage of cell wall ultimately. In summary, the surface capping with borate on NiO nanopaticles will suppress the release of the Ni2+ ions and impede the contact between the NiO nanoparticle and cell wall, which ultimately decreased the cytotoxicity of NiO nanoparticles.

  13. Tip cap for a turbine rotor blade

    DOEpatents

    Kimmel, Keith D

    2014-03-25

    A turbine rotor blade with a spar and shell construction, and a tip cap that includes a row of lugs extending from a bottom side that form dovetail grooves that engage with similar shaped lugs and grooves on a tip end of the spar to secure the tip cap to the spar against radial displacement. The lug on the trailing edge end of the tip cap is aligned perpendicular to a chordwise line of the blade in the trailing edge region in order to minimize stress due to the lugs wanting to bend under high centrifugal loads. A two piece tip cap with lugs at different angles will reduce the bending stress even more.

  14. The ATLAS TRT end-cap detectors

    NASA Astrophysics Data System (ADS)

    ATLAS TRT Collaboration; Abat, E.; Addy, T. N.; Åkesson, T. P. A.; Alison, J.; Anghinolfi, F.; Arik, E.; Arik, M.; Atoian, G.; Auerbach, B.; Baker, O. K.; Banas, E.; Baron, S.; Bault, C.; Becerici, N.; Beddall, A.; Beddall, A. J.; Bendotti, J.; Benjamin, D. P.; Bertelsen, H.; Bingul, A.; Blampey, H.; Bocci, A.; Bochenek, M.; Bondarenko, V. G.; Bychkov, V.; Callahan, J.; Capeáns Garrido, M.; Cardiel Sas, L.; Catinaccio, A.; Cetin, S. A.; Chandler, T.; Chritin, R.; Cwetanski, P.; Dam, M.; Danielsson, H.; Danilevich, E.; David, E.; Degenhardt, J.; Di Girolamo, B.; Dittus, F.; Dixon, N.; Dobos, D.; Dogan, O. B.; Dolgoshein, B. A.; Dressnandt, N.; Driouchi, C.; Ebenstein, W. L.; Eerola, P.; Egede, U.; Egorov, K.; Evans, H.; Farthouat, P.; Fedin, O. L.; Fowler, A. J.; Fratina, S.; Froidevaux, D.; Fry, A.; Gagnon, P.; Gavrilenko, I. L.; Gay, C.; Ghodbane, N.; Godlewski, J.; Goulette, M.; Gousakov, I.; Grigalashvili, N.; Grishkevich, Y.; Grognuz, J.; Hajduk, Z.; Hance, M.; Hansen, F.; Hansen, J. B.; Hansen, J. D.; Hansen, P. H.; Hare, G. A.; Harvey, A., Jr.; Hauviller, C.; High, A.; Hulsbergen, W.; Huta, W.; Issakov, V.; Istin, S.; Jain, V.; Jarlskog, G.; Jeanty, L.; Kantserov, V. A.; Kaplan, B.; Kapliy, A. S.; Katounine, S.; Kayumov, F.; Keener, P. T.; Kekelidze, G. D.; Khabarova, E.; Khristachev, A.; Kisielewski, B.; Kittelmann, T. H.; Kline, C.; Klinkby, E. B.; Klopov, N. V.; Ko, B. R.; Koffas, T.; Kondratieva, N. V.; Konovalov, S. P.; Koperny, S.; Korsmo, H.; Kovalenko, S.; Kowalski, T. Z.; Krüger, K.; Kramarenko, V.; Kudin, L. G.; LeBihan, A.-C.; LeGeyt, B. C.; Levterov, K.; Lichard, P.; Lindahl, A.; Lisan, V.; Lobastov, S.; Loginov, A.; Loh, C. W.; Lokwitz, S.; Long, M. C.; Lucas, S.; Lucotte, A.; Luehring, F.; Lundberg, B.; Mackeprang, R.; Maleev, V. P.; Manara, A.; Mandl, M.; Martin, A. J.; Martin, F. F.; Mashinistov, R.; Mayers, G. M.; McFarlane, K. W.; Mialkovski, V.; Mills, B. M.; Mindur, B.; Mitsou, V. A.; Mjörnmark, J. U.; Morozov, S. V.; Morris, E.; Mouraviev, S. V.; Muir, A. M.; Munar, A.; Nadtochi, A. V.; Nesterov, S. Y.; Newcomer, F. M.; Nikitin, N.; Novgorodova, O.; Novodvorski, E. G.; Ogren, H.; Oh, S. H.; Oleshko, S. B.; Olivito, D.; Olszowska, J.; Ostrowicz, W.; Passmore, M. S.; Patrichev, S.; Penwell, J.; Perez-Gomez, F.; Peshekhonov, V. D.; Petersen, T. C.; Petti, R.; Placci, A.; Poblaguev, A.; Pons, X.; Price, M. J.; hne, O. Rø; Reece, R. D.; Reilly, M. B.; Rembser, C.; Romaniouk, A.; Rousseau, D.; Rust, D.; Ryabov, Y. F.; Ryjov, V.; Söderberg, M.; Savenkov, A.; Saxon, J.; Scandurra, M.; Schegelsky, V. A.; Scherzer, M. I.; Schmidt, M. P.; Schmitt, C.; Sedykh, E.; Seliverstov, D. M.; Shin, T.; Shmeleva, A.; Sivoklokov, S.; Smirnov, S. Yu; Smirnova, L.; Smirnova, O.; Smith, P.; Sosnovtsev, V. V.; Sprachmann, G.; Subramania, S.; Suchkov, S. I.; Sulin, V. V.; Szczygiel, R. R.; Tartarelli, G.; Thomson, E.; Tikhomirov, V. O.; Tipton, P.; Valls Ferrer, J. A.; Van Berg, R.; Vassilakopoulos, V. I.; Vassilieva, L.; Wagner, P.; Wall, R.; Wang, C.; Whittington, D.; Williams, H. H.; Zhelezko, A.; Zhukov, K.

    2008-10-01

    The ATLAS TRT end-cap is a tracking drift chamber using 245,760 individual tubular drift tubes. It is a part of the TRT tracker which consist of the barrel and two end-caps. The TRT end-caps cover the forward and backward pseudo-rapidity region 1.0 < |η| < 2.0, while the TRT barrel central η region |η| < 1.0. The TRT system provides a combination of continuous tracking with many measurements in individual drift tubes (or straws) and of electron identification based on transition radiation from fibers or foils interleaved between the straws themselves. Along with other two sub-system, namely the Pixel detector and Semi Conductor Tracker (SCT), the TRT constitutes the ATLAS Inner Detector. This paper describes the recently completed and installed TRT end-cap detectors, their design, assembly, integration and the acceptance tests applied during the construction.

  15. Commercial Crew Program CCiCap Partners

    NASA Video Gallery

    NASA's Commercial Crew Program and its newest Commercial Crew Integrated Capability (CCiCap) partners are embracing the American spirit as they advance their integrated rocket and spacecraft design...

  16. DESIGN CONSIDERATION INVOLVING ACTIVE SEDIMENT CAPS

    EPA Science Inventory

    When contaminated sediments pose unacceptable risks to human health and the environment, management activities such as removal, treatment, or isolation of contaminated sediments may be required. Various capping designs are being considered for isolating contaminated sediment are...

  17. DESIGN CONSIDERATION INVOLVING ACTIVE SEDIMENT CAPS (PRESENTATION)

    EPA Science Inventory

    When contaminated sediments pose unacceptable risks to human health and the environment, management activities such as removal, treatment, or isolation of contaminated sediments may be required. Various capping designs are being considered for isolating contaminated sediment are...

  18. Textures in south polar ice cap #1

    NASA Technical Reports Server (NTRS)

    1998-01-01

    Textures of the south polar permanent residual ice cap and polar layered terrains. This 30 x 29 km area image (frame 7709) is centered near 87 degrees south, 77 degrees west.

    Figure caption from Science Magazine

  19. Textures in south polar ice cap #2

    NASA Technical Reports Server (NTRS)

    1998-01-01

    Textures of the south polar permanent residual ice cap and polar layered terrains. This 15 x 14 km area image (frame 7306) is centered near 87 degrees south, 341 degrees west.

    Figure caption from Science Magazine

  20. CCiCap: Sierra Nevada Corporation

    NASA Video Gallery

    NASA announced today its plans to partner with Sierra Nevada Corp. (SNC) for the next phase of the agency's Commercial Crew Program (CCP). Called Commercial Crew integrated Capability (CCiCap), the...

  1. Perfluorocarbon vapor tagging of blasting cap detonators

    DOEpatents

    Dietz, R.N.; Senum, G.I.

    A plug for a blasting cap is made of an elastomer in which is dissolved a perfluorocarbon. The perfluorocarbon is released as a vapor into the ambient over a long period of time to serve as a detectable taggant.

  2. Secondary capping beams for offshore drilling platforms

    SciTech Connect

    Albaugh, E. K.

    1985-08-13

    A pair of I-shaped elongated girders secured to, and extending outwardly from, the capping beams of a four pile platform, to form cantilever secondary capping beams which support modified self-contained drilling rigs of a size and weight normally installed on eight pile platforms. Rig modifications comprise separation of pump and engine packages, a pipe rack extension, and a novel skidding system.

  3. Truncated Dual-Cap Nucleation Site Development

    NASA Technical Reports Server (NTRS)

    Matson, Douglas M.; Sander, Paul J.

    2012-01-01

    During heterogeneous nucleation within a metastable mushy-zone, several geometries for nucleation site development must be considered. Traditional spherical dual cap and crevice models are compared to a truncated dual cap to determine the activation energy and critical cluster growth kinetics in ternary Fe-Cr-Ni steel alloys. Results of activation energy results indicate that nucleation is more probable at grain boundaries within the solid than at the solid-liquid interface.

  4. Enhanced gravitropism of roots with a disrupted cap actin cytoskeleton

    NASA Technical Reports Server (NTRS)

    Hou, Guichuan; Mohamalawari, Deepti R.; Blancaflor, Elison B.

    2003-01-01

    The actin cytoskeleton has been proposed to be a major player in plant gravitropism. However, understanding the role of actin in this process is far from complete. To address this problem, we conducted an analysis of the effect of Latrunculin B (Lat B), a potent actin-disrupting drug, on root gravitropism using various parameters that included detailed curvature kinetics, estimation of gravitropic sensitivity, and monitoring of curvature development after extended clinorotation. Lat B treatment resulted in a promotion of root curvature after a 90 degrees reorientation in three plant species tested. More significantly, the sensitivity of maize (Zea mays) roots to gravity was enhanced after actin disruption, as determined from a comparison of presentation time of Lat B-treated versus untreated roots. A short 10-min gravistimulus followed by extended rotation on a 1-rpm clinostat resulted in extensive gravitropic responses, manifested as curvature that often exceeded 90 degrees. Application of Lat B to the cap or elongation zone of maize roots resulted in the disruption of the actin cytoskeleton, which was confined to the area of localized Lat B application. Only roots with Lat B applied to the cap displayed the strong curvature responses after extended clinorotation. Our study demonstrates that disrupting the actin cytoskeleton in the cap leads to the persistence of a signal established by a previous gravistimulus. Therefore, actin could function in root gravitropism by providing a mechanism to regulate the proliferation of a gravitropic signal originating from the cap to allow the root to attain its correct orientation or set point angle.

  5. Enhanced gravitropism of roots with a disrupted cap actin cytoskeleton.

    PubMed

    Hou, Guichuan; Mohamalawari, Deepti R; Blancaflor, Elison B

    2003-03-01

    The actin cytoskeleton has been proposed to be a major player in plant gravitropism. However, understanding the role of actin in this process is far from complete. To address this problem, we conducted an analysis of the effect of Latrunculin B (Lat B), a potent actin-disrupting drug, on root gravitropism using various parameters that included detailed curvature kinetics, estimation of gravitropic sensitivity, and monitoring of curvature development after extended clinorotation. Lat B treatment resulted in a promotion of root curvature after a 90 degrees reorientation in three plant species tested. More significantly, the sensitivity of maize (Zea mays) roots to gravity was enhanced after actin disruption, as determined from a comparison of presentation time of Lat B-treated versus untreated roots. A short 10-min gravistimulus followed by extended rotation on a 1-rpm clinostat resulted in extensive gravitropic responses, manifested as curvature that often exceeded 90 degrees. Application of Lat B to the cap or elongation zone of maize roots resulted in the disruption of the actin cytoskeleton, which was confined to the area of localized Lat B application. Only roots with Lat B applied to the cap displayed the strong curvature responses after extended clinorotation. Our study demonstrates that disrupting the actin cytoskeleton in the cap leads to the persistence of a signal established by a previous gravistimulus. Therefore, actin could function in root gravitropism by providing a mechanism to regulate the proliferation of a gravitropic signal originating from the cap to allow the root to attain its correct orientation or set point angle. PMID:12644685

  6. Fourier spectra from exoplanets with polar caps and ocean glint

    NASA Astrophysics Data System (ADS)

    Visser, P. M.; van de Bult, F. J.

    2015-07-01

    Context. The weak orbital-phase dependent reflection signal of an exoplanet contains information on the planet surface, such as the distribution of continents and oceans on terrestrial planets. This light curve is usually studied in the time domain, but because the signal from a stationary surface is (quasi)periodic, analysis of the Fourier series may provide an alternative, complementary approach. Aims: We study Fourier spectra from reflected light curves for geometrically simple configurations. Depending on its atmospheric properties, a rotating planet in the habitable zone could have circular polar ice caps. Tidally locked planets, on the other hand, may have symmetric circular oceans facing the star. These cases are interesting because the high-albedo contrast at the sharp edges of the ice-sheets and the glint from the host star in the ocean may produce recognizable light curves with orbital periodicity, which could also be interpreted in the Fourier domain. Methods: We derive a simple general expression for the Fourier coefficients of a quasiperiodic light curve in terms of the albedo map of a Lambertian planet surface. Analytic expressions for light curves and their spectra are calculated for idealized situations, and dependence of the spectral peaks on the key parameters inclination, obliquity, and cap size is studied. Results: The ice-scattering and ocean glint contributions can be separated out, because the coefficients for glint are all positive, whereas ice sheets lead to even-numbered, higher harmonics. An in-view polar cap on a planet without axial tilt only produces a single peak. The special situation of edge-on observation, which is important for planets in transit, leads to the most pronounced spectral behavior. Then the respective spectra from planets with a circumventing ocean, a circular ocean (eyeball world), polar caps, and rings, have characteristic power-law tails n-2, n-7/2, n-4, and (-1)n + 1n-2. Conclusions: Promising recently discovered

  7. The effect of polar caps on obliquity

    NASA Technical Reports Server (NTRS)

    Lindner, B. L.

    1993-01-01

    Rubincam has shown that the Martian obliquity is dependent on the seasonal polar caps. In particular, Rubincam analytically derived this dependence and showed that the change in obliquity is directly proportional to the seasonal polar cap mass. Rubincam concludes that seasonal friction does not appear to have changed Mars' climate significantly. Using a computer model for the evolution of the Martian atmosphere, Haberle et al. have made a convincing case for the possibility of huge polar caps, about 10 times the mass of the current polar caps, that exist for a significant fraction of the planet's history. Since Rubincam showed that the effect of seasonal friction on obliquity is directly proportional to polar cap mass, a scenario with a ten-fold increase in polar cap mass over a significant fraction of the planet's history would result in a secular increase in Mars' obliquity of perhaps 10 degrees. Hence, the Rubincam conclusion of an insignificant contribution to Mars' climate by seasonal friction may be incorrect. Furthermore, if seasonal friction is an important consideration in the obliquity of Mars, this would significantly alter the predictions of past obliquity.

  8. An inorganic capping strategy for the seeded growth of versatile bimetallic nanostructures

    SciTech Connect

    Pei, Yuchen; Maligal-Ganesh, Raghu V.; Xiao, Chaoxian; Goh, Tian -Wei; Brashler, Kyle; Gustafson, Jeffrey A.; Huang, Wenyu

    2015-09-11

    Metal nanostructures have attracted great attention in various fields due to their tunable properties through precisely tailored sizes, compositions and structures. Using mesoporous silica (mSiO2) as the inorganic capping agent and encapsulated Pt nanoparticles as the seeds, we developed a robust seeded growth method to prepare uniform bimetallic nanoparticles encapsulated in mesoporous silica shells (PtM@mSiO2, M = Pd, Rh, Ni and Cu). Unexpectedly, we found that the inorganic silica shell is able to accommodate an eight-fold volume increase in the metallic core by reducing its thickness. The bimetallic nanoparticles encapsulated in mesoporous silica shells showed enhanced catalytic properties and thermal stabilities compared with those prepared with organic capping agents. As a result, this inorganic capping strategy could find a broad application in the synthesis of versatile bimetallic nanostructures with exceptional structural control and enhanced catalytic properties.

  9. An inorganic capping strategy for the seeded growth of versatile bimetallic nanostructures

    DOE PAGESBeta

    Pei, Yuchen; Maligal-Ganesh, Raghu V.; Xiao, Chaoxian; Goh, Tian -Wei; Brashler, Kyle; Gustafson, Jeffrey A.; Huang, Wenyu

    2015-09-11

    Metal nanostructures have attracted great attention in various fields due to their tunable properties through precisely tailored sizes, compositions and structures. Using mesoporous silica (mSiO2) as the inorganic capping agent and encapsulated Pt nanoparticles as the seeds, we developed a robust seeded growth method to prepare uniform bimetallic nanoparticles encapsulated in mesoporous silica shells (PtM@mSiO2, M = Pd, Rh, Ni and Cu). Unexpectedly, we found that the inorganic silica shell is able to accommodate an eight-fold volume increase in the metallic core by reducing its thickness. The bimetallic nanoparticles encapsulated in mesoporous silica shells showed enhanced catalytic properties and thermalmore » stabilities compared with those prepared with organic capping agents. As a result, this inorganic capping strategy could find a broad application in the synthesis of versatile bimetallic nanostructures with exceptional structural control and enhanced catalytic properties.« less

  10. An inorganic capping strategy for the seeded growth of versatile bimetallic nanostructures

    NASA Astrophysics Data System (ADS)

    Pei, Yuchen; Maligal-Ganesh, Raghu V.; Xiao, Chaoxian; Goh, Tian-Wei; Brashler, Kyle; Gustafson, Jeffrey A.; Huang, Wenyu

    2015-10-01

    Metal nanostructures have attracted great attention in various fields due to their tunable properties through precisely tailored sizes, compositions and structures. Using mesoporous silica (mSiO2) as the inorganic capping agent and encapsulated Pt nanoparticles as the seeds, we developed a robust seeded growth method to prepare uniform bimetallic nanoparticles encapsulated in mesoporous silica shells (PtM@mSiO2, M = Pd, Rh, Ni and Cu). Unexpectedly, we found that the inorganic silica shell is able to accommodate an eight-fold volume increase in the metallic core by reducing its thickness. The bimetallic nanoparticles encapsulated in mesoporous silica shells showed enhanced catalytic properties and thermal stabilities compared with those prepared with organic capping agents. This inorganic capping strategy could find a broad application in the synthesis of versatile bimetallic nanostructures with exceptional structural control and enhanced catalytic properties.Metal nanostructures have attracted great attention in various fields due to their tunable properties through precisely tailored sizes, compositions and structures. Using mesoporous silica (mSiO2) as the inorganic capping agent and encapsulated Pt nanoparticles as the seeds, we developed a robust seeded growth method to prepare uniform bimetallic nanoparticles encapsulated in mesoporous silica shells (PtM@mSiO2, M = Pd, Rh, Ni and Cu). Unexpectedly, we found that the inorganic silica shell is able to accommodate an eight-fold volume increase in the metallic core by reducing its thickness. The bimetallic nanoparticles encapsulated in mesoporous silica shells showed enhanced catalytic properties and thermal stabilities compared with those prepared with organic capping agents. This inorganic capping strategy could find a broad application in the synthesis of versatile bimetallic nanostructures with exceptional structural control and enhanced catalytic properties. Electronic supplementary information (ESI

  11. Lead Toxicity

    MedlinePlus

    ... homes. • Most people, especially children, who suffer from lead poisoning are exposed through lead-contaminated household dust or ... and six if they are at risk of lead poisoning (see: ). Who can I call to get more ...

  12. Determination of lead isotopes in a new Greenland deep ice core at the sub-picogram per gram level by thermal ionization mass spectrometry using an improved decontamination method.

    PubMed

    Han, Changhee; Burn-Nunes, Laurie J; Lee, Khanghyun; Chang, Chaewon; Kang, Jung-Ho; Han, Yeongcheol; Hur, Soon Do; Hong, Sungmin

    2015-08-01

    An improved decontamination method and ultraclean analytical procedures have been developed to minimize Pb contamination of processed glacial ice cores and to achieve reliable determination of Pb isotopes in North Greenland Eemian Ice Drilling (NEEM) deep ice core sections with concentrations at the sub-picogram per gram level. A PL-7 (Fuso Chemical) silica-gel activator has replaced the previously used colloidal silica activator produced by Merck and has been shown to provide sufficiently enhanced ion beam intensity for Pb isotope analysis for a few tens of picograms of Pb. Considering the quantities of Pb contained in the NEEM Greenland ice core and a sample weight of 10 g used for the analysis, the blank contribution from the sample treatment was observed to be negligible. The decontamination and analysis of the artificial ice cores and selected NEEM Greenland ice core sections confirmed the cleanliness and effectiveness of the overall analytical process.

  13. Al capping layers for nondestructive x-ray photoelectron spectroscopy analyses of transition-metal nitride thin films

    SciTech Connect

    Greczynski, Grzegorz Hultman, Lars; Petrov, Ivan; Greene, J. E.

    2015-09-15

    X-ray photoelectron spectroscopy (XPS) compositional analyses of materials that have been air exposed typically require ion etching in order to remove contaminated surface layers. However, the etching step can lead to changes in sample surface and near-surface compositions due to preferential elemental sputter ejection and forward recoil implantation; this is a particular problem for metal/gas compounds and alloys such as nitrides and oxides. Here, the authors use TiN as a model system and compare XPS analysis results from three sets of polycrystalline TiN/Si(001) films deposited by reactive magnetron sputtering in a separate vacuum chamber. The films are either (1) air-exposed for ≤10 min prior to insertion into the ultrahigh-vacuum (UHV) XPS system; (2) air-exposed and subject to ion etching, using different ion energies and beam incidence angles, in the XPS chamber prior to analysis; or (3) Al-capped in-situ in the deposition system prior to air-exposure and loading into the XPS instrument. The authors show that thin, 1.5–6.0 nm, Al capping layers provide effective barriers to oxidation and contamination of TiN surfaces, thus allowing nondestructive acquisition of high-resolution core-level spectra representative of clean samples, and, hence, correct bonding assignments. The Ti 2p and N 1s satellite features, which are sensitive to ion bombardment, exhibit high intensities comparable to those obtained from single-crystal TiN/MgO(001) films grown and analyzed in-situ in a UHV XPS system and there is no indication of Al/TiN interfacial reactions. XPS-determined N/Ti concentrations acquired from Al/TiN samples agree very well with Rutherford backscattering and elastic recoil analysis results while ion-etched air-exposed samples exhibit strong N loss due to preferential resputtering. The intensities and shapes of the Ti 2p and N 1s core level signals from Al/TiN/Si(001) samples do not change following long-term (up to 70 days) exposure to ambient conditions

  14. Polar cap response to the solar wind density jump under constant southward IMF

    NASA Astrophysics Data System (ADS)

    Belenkaya, E. S.; Kalegaev, V. V.; Blokhina, M. S.

    2014-11-01

    Sharp changes of the solar wind parameters determining the dynamic pressure jump lead to strong magnetosphere-ionosphere disturbances. Here the effect on the Earth's ionospheric high latitudes of the solar wind dynamic pressure pulse caused only by the increase of the interplanetary plasma density under southward constant IMF is considered. We investigate reaction of the cross-polar cap potential on the increase of AL index and/or jump of the solar wind density. It is found that for the case of 10 January 1997 the main contribution to the polar cap potential drop increase gave the growth of AL index relative to the input of the solar wind density jump. We also study the influence of the solar wind density increase on the crosspolar cap potential for the quiet magnetospheric conditions. It occurred that the polar cap potential difference decreases with the great increase of the interplanetary plasma density. For the disturbed magnetosphere the main role in the polar cap potential drop increase plays increase of AL. Thus, we found the change of the cross-polar cap potential due to the AL index variations and/or the solar wind density drop even in a case when the interplanetary electric field is constant.

  15. The Medieval Warm/Little Ice Age Transition as Recorded by Ice Caps in East Greenland

    NASA Astrophysics Data System (ADS)

    Lowell, T. V.; Kelly, M. A.; Hall, B. L.; Bennike, O.; Honsaker, W. M.; Levy, L.; Lusas, A.

    2011-12-01

    The spatial-temporal distribution of late Holocene temperature changes over the last 2000 yr is still being defined. The high Arctic is often represented by the borehole tem-perature records from GISP and Dye 3. These both show a distinct, but different magni-tude, Medieval warm interval from ~500 to ~1200 AD, with two cold intervals after 1500 AD. However small glaciers in the high Arctic appear reflect a more complex late Holo-cene pattern. On the eastern coast of Greenland two ice caps record a warm interval from 400 AD to 600 AD but cooling after that. These ice caps, Istorvet ,on the coast beside the cold East Greenland Current, and Bregne ice cap, ~ 100 km inland, have yielded organic remains from > 50 sites. A preliminary interpretation is that the organic remains record the last time these ice caps were as small or smaller than the present configuration. Exposure ages show these ice caps reached their post glacial maximum extent within the last 1000 yr. The Istorvet ice cap is thought to show initial cooling at ~AD 884 and an advance to within 500 m of the Little Ice Age extent at AD 1022 and its fullest extent at 1125 AD. Core sediments suggest that extent was maintained until 1750 AD. Results from the inland site indicate a retracted ice cap from AD 1054 to 1393, followed by expansion. Although some of these events appear to have correlative events recorded in SST or sea ice near Iceland. Taken together they appear to have a different signature than lo-cations further south. This may indicate that temperature patterns at high latitudes are only partly coupled with those at lower latitudes.

  16. Trapped Air in Glacial Ice from the base of Penny, Agassiz, and Devon Ice Caps, Canada

    NASA Astrophysics Data System (ADS)

    Yau, A. M.; Fisher, D.

    2013-12-01

    Basal ice from the Canadian Arctic ice caps, Penny, Agassiz, and Devon, has long been suggested to date back into the last interglacial, or Stage 5e. Cores from all three ice caps contain long Holocene sections with heavy δ18Oice values, overlaying condensed glacial sections with light δ18Oice values, which are underlain by ~1-7 m of ice with δ18Oice values similar to that of the Holocene, suggesting accumulation during the last interglacial. However, the origin of the ice, whether the ice is regelation/segregated or pristine glacial ice has been debated, with important implications as to whether or not ice caps in the Canadian arctic persisted through the last interglacial. Here we present analyses of the trapped air from the bottom portions of Penny, Agassiz, and Devon ice caps to provide context about the nature of the basal ice. Geochemical analyses of N2/Ar, O2/Ar, O2/N2, δ15N2, δ18OATM, and total air content (TAC) indicate a spectrum of ice conditions in basal ice. Low N2/Ar ratios and low TAC indicate partial melting in some of the samples from all three ice caps. High δ15N2, high TAC, and N2/Ar ratios close to air indicate that clean glacial ice is also present in the basal section of each ice cap. Low O2/Ar and high δ18OATM indicates microbial respiration in most samples. The lowest δ18OATM values, near 0‰, indicate trapped air ages >80 ka for the Devon and Agassiz ice caps.

  17. Enhancement of the optical performances for the LED backlight systems with a novel lens cap

    NASA Astrophysics Data System (ADS)

    Chang, Jee-Gong; Liao, Charles Lun-De; Hwang, Chi-Chuan

    2006-08-01

    A novel dual-cone-shaped side-emitting lens cap for High Brightness Light Emitting Diodes (HB-LEDs) is proposed for improving brightness and high uniformity of the direct LED acklight Units (BLUs) for large area LCD-TVs. Combining the designed lens cap with red, green and blue (RGB) chips on a Metal Core Printed Circuit Board (MCPCB), the LED module with the proposed cap is able to provide a compact white light source with unique features such as instant color variability and lower power usage, etc. The dual-cone-shaped of the proposed lens cap is designed to emitting most of the light rays to the sides, only a small portion of light upward along the optical axis of the lens, providing a uniform luminance distribution and the high brightness on the backlight. In addition, a small, half-circle eflective surface is designed and upon the proposed LED module about 10mm, the surfaces of which are attached with reflective films to increase the level of light mixing in the larger, global reflector optical box. With the structure of the LED module well designed, the LED backlight Module would design for the large area LCD-TV using the fewer number of LEDs and also have low power consumption. The results indeed identify the attributes of the BLU, which make it possible to achieve excellent backlight performance using a direct illumination approach from the light source of "Dual-Cone-Shaped Side-Emitting Lens Cap of LEDs".

  18. GaAs nanowires with oxidation-proof arsenic capping for the growth of an epitaxial shell.

    PubMed

    Guan, X; Becdelievre, J; Benali, A; Botella, C; Grenet, G; Regreny, P; Chauvin, N; Blanchard, N P; Jaurand, X; Saint-Girons, G; Bachelet, R; Gendry, M; Penuelas, J

    2016-08-25

    We propose an arsenic-capping/decapping method, allowing the growth of an epitaxial shell around the GaAs nanowire (NW) core which is exposed to an ambient atmosphere, and without the introduction of impurities. Self-catalyzed GaAs NW arrays were firstly grown on Si(111) substrates by solid-source molecular beam epitaxy. Aiming for protecting the active surface of the GaAs NW core, the arsenic-capping/decapping method has been applied. To validate the effect of this method, different core/shell NWs have been fabricated. Analyses highlight the benefit of the As capping-decapping method for further epitaxial shell growth: an epitaxial shell with a smooth surface is achieved in the case of As-capped-decapped GaAs NWs, comparable to the in situ grown GaAs/AlGaAs NWs. This As capping method opens a way for the epitaxial growth of heterogeneous material shells such as functional oxides using different reactors. PMID:27513669

  19. Measurement of fibrous cap thickness in atherosclerotic plaques by spatiotemporal analysis of laser speckle images

    NASA Astrophysics Data System (ADS)

    Nadkarni, Seemantini K.; Bilenca, Alberto; Bouma, Brett E.; Tearney, Guillermo J.

    2006-03-01

    Necrotic-core fibroatheromas (NCFA) with thin, mechanically weak fibrous caps overlying lipid cores comprise the majority of plaques that rupture and cause acute myocardial infarction. Laser speckle imaging (LSI) has been recently demonstrated to enable atherosclerotic plaque characterization with high accuracy. We investigate spatio-temporal analysis of LSI data, in conjunction with diffusion theory and Monte Carlo modeling of light transport, to estimate fibrous cap thickness in NCFAs. Time-varying laser speckle images of 20 NCFAs are selected for analysis. Spatio-temporal intensity fluctuations are analyzed by exponential fitting of the windowed normalized cross-correlation of sequential laser speckle patterns to obtain the speckle decorrelation time constant, τ(ρ), as a function of distance ρ from the source entry location. The distance, ρ‧, at which τ(ρ) dropped to 65% of its maximum value is recorded. Diffusion theory and Monte Carlo models are utilized to estimate the maximum photon penetration depth, zmax(ρ‧), for a distance equal to ρ‧, measured from LSI. Measurements of zmax(ρ‧) correlate well with histological measurements of fibrous cap thickness (R=0.78,p<0.0001), and paired t-tests show no significant difference between the groups (p=0.4). These results demonstrate that spatio-temporal LSI may allow the estimation of fibrous cap thickness in NCFAs, which is an important predictor of plaque stability.

  20. 75 FR 49527 - Caps Visual Communications, LLC; Black Dot Group; Formerly Known as Caps Group Acquisition, LLC...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-13

    ... Employment and Training Administration Caps Visual Communications, LLC; Black Dot Group; Formerly Known as... Adjustment Assistance on June 24, 2010, applicable to workers of Caps Visual Communications, LLC, Black Dot..., Caps Visual Communications, LLC, Black Dot Group, formerly known as Caps Group Acquisition,...

  1. Actin capping proteins, CapZ (β-actinin) and tropomodulin in amphioxus striated muscle.

    PubMed

    Bao, Yulong; Kake, Takei; Hanashima, Akira; Nomiya, Yui; Kubokawa, Kaoru; Kimura, Sumiko

    2012-11-15

    CapZ (β-actinin) and tropomodulin (Tmod) are capping proteins involved in the maintenance of thin filaments in vertebrate skeletal muscles. In this study, we focused on amphioxus, the most primitive chordate. We searched for CapZ and Tmod genes in the amphioxus genome and determined their primary structures. Amphioxus possess one CapZα gene (CAPZA) and one CapZβ gene (CAPZB), and the transcripts of these genes were found to be 67%-85% identical to those of human CapZ genes. On the other hand, amphioxus contain one Tmod gene (TMOD), and the product of this gene has an identity of approximately 50% with human Tmod genes 1-4. However, helix 2 of amphioxus Tmod, which is involved in protein-binding to tropomyosin, was highly conserved with approximately 74% identity to human Tmod genes. Western blotting indicated the presence of CapZ and Tmod in the striated muscle of amphioxus. These results suggest that unlike most of vertebrates, such as fish, amphibian, bird, and mammal, CapZ from amphioxus striated muscle is derived from two genes CAPZA and CAPZB, and Tmod is derived from one TMOD gene.

  2. CAP - JET PROPULSION LABORATORY CONTAMINATION ANALYSIS PROGRAM

    NASA Technical Reports Server (NTRS)

    Millard, J. M.

    1994-01-01

    The Jet Propulsion Laboratory Contamination Analysis Program (CAP) is a generalized transient executive analysis computer code which solves realistic mass transport problems in the free molecular flow environment. These transport problems involve mass flux from surface source emission and re-emission, venting, and engine emission. CAP solution capability allows for one-bounce mass reflections if required. CAP was developed to solve thin-film contamination problems in the free molecular flow environment, the intent being to provide a powerful analytic tool for evaluating spacecraft contamination problems. The solution procedure uses an enclosure method based on a lumped-parameter multinodal approach with mass exchange between nodes. Transient solutions are computed by the finite difference Euler method. First-order rate theory is used to represent surface emission and reemission (user care must be taken to insure the problem is appropriate for such behavior), and all surface emission and reflections are assumed diffuse. CAP does not include the effects of post-deposition chemistry or interaction with the ambient atmosphere. CAP reads in a model represented by a multiple-block data stream. CAP allows the user to edit the input data stream and stack sequential editing operations (or cases) in order to make complex changes in behavior (surface temperatures, engine start-up and shut-down, etc.) in a single run if desired. The eight data blocks which make up the input data stream consist of problem control parameters, nodal data (area, temperature, mass, etc.), engine or vent distribution factors (based upon plume definitions), geometric configuration factors (diffuse surface emission), surface capture coefficient tables, source emission rate constant tables, reemission rate constant tables, and partial node to body collapse capability (for deposition rates only). The user must generate this data stream, since neither the problem-specific geometric relationships, the

  3. Transmission Through Carbon Nanotubes with Polyhedral Caps

    NASA Technical Reports Server (NTRS)

    Anantram, M. P.; Govindan, T. R.

    1999-01-01

    We study electron transport between capped carbon nanotubes and a substrate, and relate this transport to the local density of states in the cap. Our results show that that the transmission probability mimics the behavior of the density of states at all energies except those that correspond to localized states. For a capped carbon nanotube that is not connected to a substrate, the localized states do not couple to the coexisting continuum states. However, close proximity of a substrate causes hybridization between these states. As a result, new transmission paths open from substrate states to nanotube continuum states via the localized states in the cap. We show that the interference between various paths gives rise to transmission antiresonances with the minimum equal to zero at the energy of the localized state. The presence of defects in the tube places close to the cap transforms antiresonances into resonances. Depending on the spatial position of defects, these resonant states are capable of carrying a large current. The results of this paper are of relevance to carbon nanotube based studies on molecular electronics and probe tip applications.

  4. Eddy intrustion of hot plasma into the polar cap and formation of polar-cap arcs

    NASA Technical Reports Server (NTRS)

    Chiu, Y. T.; Gorney, D. J.

    1983-01-01

    Under the simple postulate that multiple large scale detachable magnetospheric convection eddies can exist in the vicinity of the convection reversal boundary and in the polar cap, by Kelvin-Helmholtz instability or otherwise, it is shown that a number of seemingly disconnected plasma and electric field observations in the polar cap can be organized into a theory of magnetosheath and plasmasheet plasma intrusion into the polar cap. Current theory of inverted V structures then predicts existence of similar, but weaker, structures at the eddy convection reversal boundaries in the polar cap. A possible consequence is that the polar cap auroras are natural offshoots from discrete oval arcs and evidently are formed by similar processes. The two arc systems can occassionally produce an optical image in the form of the theta aurora.

  5. Lead Poisoning

    MedlinePlus

    ... can be found in all parts of our environment. Much of it comes from human activities such as mining and manufacturing. Lead used to be in paint; older houses may still have lead paint. You could be exposed to lead by Eating food or drinking water that contains lead. Water pipes in older homes ...

  6. Lead poisoning

    SciTech Connect

    Rekus, J.F.

    1992-08-01

    Construction workers who weld, cut or blast structural steel coated with lead-based paint are at significant risk of lead poisoning. Although technology to control these exposures may not have existed when the lead standard was promulgated, it is available today. Employers who do not take steps to protect their employees from lead exposure may be cited and fined severely for their failure.

  7. Science goals for a Mars Polar Cap subsurface mission : optical approaches for investigations of inclusions in ice

    NASA Technical Reports Server (NTRS)

    Carsey, Frank; Mogensen, Claus T.; Behar, Alberto; Engelhardt, Hermann; Lane, Arthur L.

    2002-01-01

    The Mars Polar Caps are highly interesting features of Mars and have received much recent attention with new and exciting data on morphology, basal units, and layered outcroppings. We have examined the climatological, glaciological, and geological issues associated with a subsurface exploration of the Mars North Polar Cap and have determined that a finescale optical examination of ice in a borehole, to examine the stratigraphy, geochemistry and geochronology of the ice, is feasible. This information will enable reconstruction of the development of the cap as well as prediction of the properties of its ice. We present visible imagery taken of dust inclusions in archived Greenland ice cores as well as in-situ images of accreted lithologic inclusions in West Antarctica, and we argue for use of this kind of data in Mars climate reconstruction as has been successful with Greenland and Antarctic ice core analysis. .

  8. Science goals for a Mars Polar Cap subsurface mission : optical approaches for investiagations of inclusions in ice

    NASA Technical Reports Server (NTRS)

    Mogensen, Claus T.; Carsey, Frank D.; Behar, Alberto; Engelhardt, Hermann; Lane, Arthur L.

    2002-01-01

    The Mars Polar Caps are highly interesting features of Mars and have received much recent attention with new and exciting data on morphology, basal units, and layered outcroppings. We have examined the climatological, glaciological, and geological issues associated with a subsurface exploration of the Mars North Polar Cap and have determined that a finescale optical examination of ice in a borehole, to examine the stratigraphy, geochemistry and geochronology of the ice, is feasible. This information will enable reconstruction of the development of the cap as well as predication of the properties of its ice. We present visible imagery taken of dust inclusions in archived Greenland ice cores as well as in-situ images of accreted lithologic inclusions in West Antarctica, and we argue for use of this kind of data in Mars climate reconstruction as has been successful with Greenland and Antarctic ice core anlaysis.

  9. Fluid core size of Mars from detection of the solar tide

    NASA Technical Reports Server (NTRS)

    Yoder, C. F.; Konopliv, A. S.; Yuan, D. N.; Standish, E. M.; Folkner, W. M.

    2003-01-01

    The solar tidal deformation of Mars, measured by its k2 potential Love number, has been obtained from an analysis of Mars Global Surveyor radio tracking. The observed k2 of 0.153 +/- 0.017 is large enough to rule out a solid iron core and so indicates that at least the outer part of the core is liquid. The inferred core radius is between 1520 and 1840 kilometers and is independent of many interior properties, although partial melt of the mantle is one factor that could reduce core size. Ice-cap mass changes can be deduced from the seasonal variations in air pressure and the odd gravity harmonic J3, given knowledge of cap mass distribution with latitude. The south cap seasonal mass change is about 30 to 40% larger than that of the north cap.

  10. Fluid core size of Mars from detection of the solar tide.

    PubMed

    Yoder, C F; Konopliv, A S; Yuan, D N; Standish, E M; Folkner, W M

    2003-04-11

    The solar tidal deformation of Mars, measured by its k2 potential Love number, has been obtained from an analysis of Mars Global Surveyor radio tracking. The observed k2 of 0.153 +/- 0.017 is large enough to rule out a solid iron core and so indicates that at least the outer part of the core is liquid. The inferred core radius is between 1520 and 1840 kilometers and is independent of many interior properties, although partial melt of the mantle is one factor that could reduce core size. Ice-cap mass changes can be deduced from the seasonal variations in air pressure and the odd gravity harmonic J3, given knowledge of cap mass distribution with latitude. The south cap seasonal mass change is about 30 to 40% larger than that of the north cap. PMID:12624177

  11. Tumor-Triggered Controlled Drug Release from Electrospun Fibers Using Inorganic Caps for Inhibiting Cancer Relapse.

    PubMed

    Zhao, Xin; Yuan, Ziming; Yildirimer, Lara; Zhao, Jingwen; Lin, Zhi Yuan William; Cao, Zhi; Pan, Guoqing; Cui, Wenguo

    2015-09-01

    A smart, tumor-trigged, controlled drug release using inorganic "caps" with CO3 (2-) functional groups in electrospun fibers is presented for inhibiting cancer relapse. When the drug-loaded intelligent electrospun fibers encounter pathological acidic environments, the inorganic gates react with the acids and produce CO2 gas, which enables water penetration into the core of the fibers to induce rapid drug release.

  12. Martian north polar cap summer water cycle

    NASA Astrophysics Data System (ADS)

    Brown, Adrian J.; Calvin, Wendy M.; Becerra, Patricio; Byrne, Shane

    2016-10-01

    A key outstanding question in Martian science is "are the polar caps gaining or losing mass and what are the implications for past, current and future climate?" To address this question, we use observations from the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) of the north polar cap during late summer for multiple Martian years, to monitor the summertime water cycle in order to place quantitative limits on the amount of water ice deposited and sublimed in late summer. We establish here for the first time the summer cycle of water ice absorption band signatures on the north polar cap. We show that in a key region in the interior of the north polar cap, the absorption band depths grow until Ls = 120, when they begin to shrink, until they are obscured at the end of summer by the north polar hood. This behavior is transferable over the entire north polar cap, where in late summer regions 'flip' from being net sublimating into net condensation mode. This transition or 'mode flip' happens earlier for regions closer to the pole, and later for regions close to the periphery of the cap. The observations and calculations presented herein estimate that on average a water ice layer ∼70 microns thick is deposited during the Ls = 135-164 period. This is far larger than the results of deposition on the south pole during summer, where an average layer 0.6-6 microns deep has been estimated by Brown et al. (2014) Earth Planet. Sci. Lett., 406, 102-109.

  13. Holocene Fluctuations of North Ice Cap, a Proxy for Climate Conditions along the Northwestern Margin of the Greenland Ice Sheet

    NASA Astrophysics Data System (ADS)

    Kelly, M. A.; Osterberg, E. C.; Lasher, G. E.; Farnsworth, L. B.; Howley, J. A.; Axford, Y.; Zimmerman, S. R. H.

    2015-12-01

    North Ice Cap (~76.9°N, 68°W, summit elevation 1322 m asl), a small, independent ice cap in northwestern Greenland, is located within ~25 km of the Greenland Ice Sheet margin and Harald Molkte Bræ outlet glacier. We present geochronological, geomorphic and sedimentological data constraining the Holocene extents of North Ice Cap and suggest that its past fluctuations can be used as a proxy for climate conditions along the northwestern margin of the Greenland Ice Sheet. Prior work by Goldthwait (1960) used glacial geomorphology and radiocarbon ages of subfossil plants emerging along shear planes in the ice cap margin to suggest that that North Ice Cap was not present during the early Holocene and nucleated in the middle to late Holocene time, with the onset of colder conditions. Subfossil plants emerging at shear planes in the North Ice Cap margin yield radiocarbon ages of ~4.8-5.9 cal kyr BP (Goldthwait, 1960) and ~AD 1000-1350 (950-600 cal yr BP), indicating times when the ice cap was smaller than at present. In situ subfossil plants exposed by recent ice cap retreat date to ~AD 1500-1840 (450-110 cal yr BP) and indicate small fluctuations of the ice cap margin. 10Be ages of an unweathered, lichen-free drift <100 m from the present North Ice Cap margin range from ~500 to 8000 yrs ago. We suggest that the drift was deposited during the last ~500 yrs and that the older 10Be ages are influenced by 10Be inherited from a prior period of exposure. We also infer ice cap fluctuations using geochemical data from a Holocene-long sediment core from Deltasø, a downstream lake that currently receives meltwater from North Ice Cap. The recent recession of the North Ice Cap margin influenced a catastrophic drainage of a large proglacial lake, Søndre Snesø, that our field team documented in August 2012. To our knowledge, this is the first significant lowering of Søndre Snesø in historical time.

  14. Landfill capping: The Croton Point Landfill experience

    SciTech Connect

    Srinivasaraghaven, R.; Gavin, J.M.; Landi, A.M.; Ritchie, M.D.

    1996-12-31

    The Croton Point Landfill Capping involved the installation of an impermeable, geosynthetic cap and the attendant geotechnical cover soils over a 113 acre hazardous waste landfill in Croton-On-Hudson, New York. The remediation process - Remedial Investigation, Feasibility Study (RI/FS) Remedial Design and Remedial Construction lasted six years. This paper sets forth some of the insights and experiences gained during that process and provides some practical recommendations. In particular, the paper evaluates the Croton Landfill experience in regard to Health and Safety; Stormwater Control; erosion and sediment control; QA/QC; leachate treatment and disposal; and wildlife control.

  15. Valve Cap For An Electric Storage Cell

    DOEpatents

    Verhoog, Roelof; Genton, Alain

    2000-04-18

    The valve cap for an electric storage cell includes a central annular valve seat (23) and a membrane (5) fixed by its peripheral edge and urged against the seat by a piston (10) bearing thereagainst by means of a spring (12), the rear end of said spring (12) bearing on the endwall (8) of a chamber (20) formed in the cap and containing the piston (10) and the spring. A vent (19) puts the chamber (20) into communication with the atmosphere. A central orifice (26, 28) through the piston (10) and the membrane (5), enables gas from within the cell to escape via the top vent (19) when the valve opens.

  16. Steel Foil Improves Performance Of Blasting Caps

    NASA Technical Reports Server (NTRS)

    Bement, Laurence J.; Perry, Ronnie; Schimmel, Morry L.

    1990-01-01

    Blasting caps, which commonly include deep-drawn aluminum cups, give significantly higher initiation performance by application of steel foils on output faces. Steel closures 0.005 in. (0.13 mm) thick more effective than aluminum. Caps with directly bonded steel foil produce fragment velocities of 9,300 ft/s (2.8 km/s) with large craters and unpredictable patterns to such degree that no attempts made to initiate explosions. Useful in military and aerospace applications and in specialized industries as mining and exploration for oil.

  17. Pharmacy benefit caps and the chronically ill.

    PubMed

    Joyce, Geoffrey F; Goldman, Dana P; Karaca-Mandic, Pinar; Zheng, Yuhui

    2007-01-01

    In this paper we examine medication use among retirees with employer-sponsored drug coverage both with and without annual benefit limits. We find that pharmacy benefit caps are associated with higher rates of medication discontinuation across the most common therapeutic classes and that only a minority of those who discontinue use reinitiate therapy once coverage resumes. Plan members who reach their cap are more likely than others to switch plans and increase their rate of generic use; however, in most cases, the shift is temporary. Given the similarities between these plans and Part D, we make some inferences about reforms for Medicare.

  18. The use of airborne radar reflectometry to characterize near-surface snow/firn stratigraphy on Devon Ice Cap, Canadian Arctic: A path to identifying refrozen melt layers

    NASA Astrophysics Data System (ADS)

    Rutishauser, A.; Grima, C.; Sharp, M. J.; Blankenship, D. D.; Young, D. A.; Dowdeswell, J. A.

    2015-12-01

    Under present warming conditions, summer surface melt has been observed to intensify and shift towards higher elevations in the accumulation zones of Canadian Arctic ice caps. Consequently, more meltwater percolates into the near surface snow and firn, and refreezes as ice layers. This process can lead to a significant increase in firn densification rates. Knowledge of spatiotemporal variations of the near-surface firn density, especially the distribution of ice layer formation is of great importance when assessing mass change estimates from repeat altimetry measurements. Here, we present an approach for characterizing the near-surface firn stratigraphy and determining the spatial distribution of refrozen melt layers on Devon Ice Cap, using the surface echo from airborne radio-echo sounding (RES) measurements. The RES surface echo is affected by the upper few meters of snow/firn/ice and thus contains information about the near-surface properties. More specifically, the radar surface return is a combination of a coherent (Pc) and a scattering signal component (Pn). Pc is related to the dielectric constant of the probed surface, whereas Pn is related to the near surface roughness. Hence, different near-surface snow/firn properties can be investigated by analyzing the signal components Pc and Pn and their spatial variability. The Radar Statistical Reconnaissance (RSR) methodology [1] allows the extraction of Pc and Pn from the surface radar return, which then can be used to compute near-surface roughness and firn density estimates. We apply the RSR method to RES data collected on Devon Ice Cap and determine Pc and Pn values. We then compare the results to ground based RES measurements and shallow firn cores (~11 m deep) collected along the airborne RES flight lines. This comparison shows that variations in the scattering coefficient Pn correlate to changes in the pattern of near-surface firn stratigraphy revealed by the ground based RES data and firn cores. Based on

  19. Models of the Earth's Core.

    PubMed

    Stevenson, D J

    1981-11-01

    Combined inferences from seismology, high-pressure experiment and theory, geomagnetism, fluid dynamics, and current views of terrestrial planetary evolution lead to models of the earth's core with the following properties. Core formation was contemporaneous with earth accretion; the core is not in chemical equilibrium with the mantle; the outer core is a fluid iron alloy containing significant quantities of lighter elements and is probably almost adiabatic and compositionally uniform; the more iron-rich inner solid core is a consequence of partial freezing of the outer core, and the energy release from this process sustains the earth's magnetic field; and the thermodynamic properties of the core are well constrained by the application of liquid-state theory to seismic and laboratory data. PMID:17839632

  20. Core fluctuations test. Revision 1

    SciTech Connect

    Betts, W.S.

    1987-06-01

    Fluctuations were first encountered in the Fort St. Vrain reactor early in cycle 1 operation, during the initial rise from 40% to 70% power. Subsequent in-core tests and operation throughout cycles 1 and 2 demonstrated that fluctuations were repeatable, occurring at core pressure drops of between 2.5 psi and 4.0 psi, and that in each instance their characteristics were very similar. Subsequently, tests and analysis were done to understand the core fluctuation phenomenon. These efforts also lead to a design fix which stopped these fluctuations in the FSV reactor core. This fix required that keys be used in addition to the keys in the core support floor which already existed. This report outlines a test plan to validate that core fluctuations will not occur in the MHTGR core. 2 refs., 12 figs., 3 tabs.

  1. Evaluation of MerCAP for Power Plant Mercury Control

    SciTech Connect

    Carl Richardson

    2008-09-30

    {trademark} performance. At Site 2, a pilot-scale array was installed in a horizontal reactor chamber designed to treat approximately 2800 acfm of flue gas obtained from downstream of the plant's flue gas desulfurization (FGD) system. The initial MerCAP{trademark} array was installed at Plant Yates in January 2004, operating continuously for several weeks before a catastrophic system failure resulting from a failed flue gas fan. A second MerCAP{trademark} array was installed in July 2006 and operated for one month before being shut down for a reasons pertaining to system performance and host site scheduling. A longer-term continuous-operation test was then conducted during the summer and fall of 2007. Tests were conducted to evaluate the impacts of flue gas flow rate, sorbent space velocity, and sorbent rinsing frequency on mercury removal performance. Detailed characterization of treated sorbent plates was carried out in an attempt to understand the nature of reactions leading to excessive corrosion of the substrate surfaces.

  2. 24. A CORE WORKER DISPLAYS THE CORE BOX AND CORES ...

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

    24. A CORE WORKER DISPLAYS THE CORE BOX AND CORES FOR A BRASS GATE VALVE BODY MADE ON A CORE BOX, CA. 1950. - Stockham Pipe & Fittings Company, 4000 Tenth Avenue North, Birmingham, Jefferson County, AL

  3. Lead poisoning.

    PubMed Central

    Landrigan, P J; Todd, A C

    1994-01-01

    Lead poisoning is the most common disease of environmental origin in the United States today. Adult lead poisoning results primarily from exposure by inhalation in the workplace. Pediatric lead poisoning results principally from the ingestion of lead from environmental media, including paint chips, dust, soil, drinking water, ceramics, and medications. Lead is toxic to many organ systems, among them developing erythrocytes, the kidneys, and the nervous system. Lead-induced toxicity to the central nervous system causes delayed development, diminished intelligence, and altered behavior. In young children, this effect has been demonstrated convincingly to occur at blood lead levels between 10 and 20 micrograms per dl. The Centers for Disease Control and Prevention has recommended that a blood lead level of 10 micrograms per dl or higher be considered evidence of increased lead absorption, and the National Academy of Sciences has concurred in that recommendation. Unresolved issues in need of further study include the frequency of screening young children for lead, the question of whether women should be offered screening for lead before conceiving a pregnancy, the role of x-ray fluorescence analysis in assessing lead in bone, and the appropriate legislative response of the United States government to lead-based paint abatement. PMID:7941534

  4. Geological and geophysical properties of cap rock in a natural CO2 occurrence, Mihályi-Répcelak area, Western Hungary

    NASA Astrophysics Data System (ADS)

    Király, Csilla; Szamosfalvi, Ágnes; Sendula, Eszter; Páles, Mariann; Kovács, István; Kónya, Péter; Falus, György; Szabó, Csaba

    2015-04-01

    The physical and geochemical consistency of the cap rock is primarily important for safe geological storage of CO2.. As a consequence of CO2 injection reactions took place between the minerals of the reservoir, the cap rock and CO2 saturated pore water. These reactions may change the mineral composition and petrophysical properties of the storage reservoir as well as the cap rock that provides the only physical barrier that retains carbon dioxide in the target reservoir formation. Study of the natural CO2 occurrences delivers information to understand which properties of a cap rock provide the sustainable closure and retainment. Knowledge of the long term effect of CO2 on the behavior of the cap rock is an important input in the selection procedure of a potential CO2 injection site. Yet, very few data exist on geochemical properties and reactivity of the cap rocks. During normal commercial operations the reservoir is typically cored, but not the cap rock. This study may enhance our knowledge about possible mineralogical reactions, which can occur in clayey-aleuritic cap rocks. The Mihályi-Répcelak natural CO2 occurrence is believed to be leakage safe. There is no known seepage on the surface. It is suggested that the aleuritic clay rich cap rock occurring at the natural reservoir can stop CO2 migration into other reservoirs or to the surface. The most important characteristics of cap rocks that they have low permeability (<0.1 mD) and porosity (eff.por. = 4%) and high clayeyness (approx. 80%). However, we demonstrate that in addition to these parameters the geochemical properties of cap rock is also important. In order to characterize the natural CO2 occurrence, we applied the following analysis, like XRD, FTIR, SEM. The petrophysical properties are determined from the interpretation of geophysical well-logs and grain size distribution. The most important result of this study that adequate petrophysical properties do not completely define the suitability of a cap

  5. Lead poisoning

    MedlinePlus

    ... lead is still found in some modern faucets. Soil contaminated by decades of car exhaust or years ... house paint scrapings. Lead is more common in soil near highways and houses. Hobbies involving soldering, stained ...

  6. Distinct Features of Cap Binding by eIF4E1b Proteins

    PubMed Central

    Kubacka, Dorota; Miguel, Ricardo Núñez; Minshall, Nicola; Darzynkiewicz, Edward; Standart, Nancy; Zuberek, Joanna

    2015-01-01

    eIF4E1b, closely related to the canonical translation initiation factor 4E (eIF4E1a), cap-binding protein is highly expressed in mouse, Xenopus and zebrafish oocytes. We have previously characterized eIF4E1b as a component of the CPEB mRNP translation repressor complex along with the eIF4E-binding protein 4E-Transporter, the Xp54/DDX6 RNA helicase and additional RNA-binding proteins. eIF4E1b exhibited only very weak interactions with m7GTP-Sepharose and, rather than binding eIF4G, interacted with 4E-T. Here we undertook a detailed examination of both Xenopus and human eIF4E1b interactions with cap analogues using fluorescence titration and homology modeling. The predicted structure of eIF4E1b maintains the α + β fold characteristic of eIF4E proteins and its cap-binding pocket is similarly arranged by critical amino acids: Trp56, Trp102, Glu103, Trp166, Arg112, Arg157 and Lys162 and residues of the C-terminal loop. However, we demonstrate that eIF4E1b is 3-fold less well able to bind the cap than eIF4E1a, both proteins being highly stimulated by methylation at N7 of guanine. Moreover, eIF4E1b proteins are distinguishable from eIF4E1a by a set of conserved amino acid substitutions, several of which are located near to cap-binding residues. Indeed, eIF4E1b possesses several distinct features, namely, enhancement of cap binding by a benzyl group at N7 position of guanine, a reduced response to increasing length of the phosphate chain and increased binding to a cap separated by a linker from Sepharose, suggesting differences in the arrangement of the protein's core. In agreement, mutagenesis of the amino acids differentiating eIF4E1b from eIF4E1a reduces cap binding by eIF4E1a 2-fold, demonstrating their role in modulating cap binding. PMID:25463438

  7. Purification and characterization of the glycoprotein hormone. cap alpha. -subunit-like material secreted by HeLa cells

    SciTech Connect

    Cox, G.S.; Rimerman, R.A.

    1988-08-23

    The protein secreted by HeLa cells that cross-reacts with antiserum developed against the ..cap alpha..-subunit of human chorionic gonadotropin (hCG) has been purified approximately 30,000-fold from concentrated culture medium by organic solvent fractionation followed by ion exchange, gel filtration, and lectin affinity chromatography. The final preparation had a specific activity (by RIA) of 6.8 x 10/sup 5/ ng of ..cap alpha../mg of protein and appeared homogeneous by electrophoresis on reducing/denaturing polyacrylamide gels (SDS-PAGE). Amino acid analysis indicated that HeLa-..cap alpha.. had a composition very similar to that of the urinary hCG ..cap alpha..-subunit. However, comparison of hCG-..cap alpha.. and HeLa-..cap alpha.. demonstrated that the tumor-associated subunit was not identical with its normal counterpart. The purified tumor protein had an apparent molecular weight greater than that of the urinary ..cap alpha..-subunit when analyzed by SDS-PAGE, and this difference was even greater when a partially purified preparation was examined by an immunoblot technique (Western). Isoelectric focusing of the HeLa and hCG subunits demonstrated that the tumor protein had a lower pI. Immunoprecipitation and electrophoresis of ..cap alpha..-subunit from HeLa cultures labeled with (/sup 3/H)fucose indicated that the tumor subunit was fucosylated, whereas analysis of hCG-..cap alpha.. hydrosylates by HPLC confirmed previous reports that the placental subunit does not contain fucose. The results indicate that, regardless of whether or not a single ..cap alpha..-subunit gene is being expressed in both normal and neoplastic tissues, posttranslational modifications lead to a highly altered subunit in the tumor. The differences observed may be useful in diagnosing neoplastic vs hyperplastic conditions and may lend insight into the mechanism of ectopic hormone production by tumors.

  8. Unsolved problems: Mesoscale polar cap flow channels' structure, propagation, and effects on space weather disturbances

    NASA Astrophysics Data System (ADS)

    Lyons, L. R.; Nishimura, Y.; Zou, Y.

    2016-04-01

    Recent evidence indicates that the magnetosphere-ionosphere system is frequently driven by dynamic mesoscale flow structures that are first seen near the dayside cusps, move across the open field line regions of the polar caps, and then enter the plasma sheet where they lead to a large variety of space weather disturbances. It will be important to uncover the features of these flow enhancements, including their structure, how they propagate across the polar cap, and what controls their dynamic effects after reaching the nightside plasma sheet.

  9. Survey of Enabling Technologies for CAPS

    NASA Technical Reports Server (NTRS)

    Antol, Jeffrey; Mazanek, Daniel D.; Koons, Robert H.

    2005-01-01

    The enabling technologies required for the development of a viable Comet/Asteroid Protection System (CAPS) can be divided into two principal areas: detection and deflection/orbit modification. With the proper funding levels, many of the technologies needed to support a CAPS architecture could be achievable within the next 15 to 20 years. In fact, many advanced detection technologies are currently in development for future in-space telescope systems such as the James Webb Space Telescope (JWST), formerly known as the Next Generation Space Telescope. It is anticipated that many of the JWST technologies would be available for application for CAPS detection concepts. Deflection/orbit modification technologies are also currently being studied as part of advanced power and propulsion research. However, many of these technologies, such as extremely high-output power systems, advanced propulsion, heat rejection, and directed energy systems, would likely be farther term in availability than many of the detection technologies. Discussed subsequently is a preliminary examination of the main technologies that have been identified as being essential to providing the element functionality defined during the CAPS conceptual study. The detailed requirements for many of the technology areas are still unknown, and many additional technologies will be identified as future in-depth studies are conducted in this area.

  10. Plasma structuring in the polar cap

    SciTech Connect

    Basu, S.; Basu, S.; Weber, E.J.; Bishop, G.J.

    1990-01-01

    Propagation experiments providing scintillation, total electron content and drift data in the field of view of an all-sky imager near the magnetic polar in Greenland are utilized to investigate the manner in which ionospheric plasma becomes structured within the polar cap. It is found that under IMF Bz southward conditions, large scale ionization patches which are convected through the dayside cusp into the polar cap get continually structured. The structuring occurs through the ExB gradient drift instability process which operates through an interaction between the antisunward plasma convection in the neutral rest frame and large scale plasma density gradients that exist at the edges of the ionization patches. It is shown that with the increase of solar activity the strength of the irregularities integrated through the ionosphere is greatly increased. Under the IMF Bz northward conditions, the plasma structuring occurs around the polar cap arcs in the presence of inhomogeneous electric field or disordered plasma convection. In that case, the irregularity generation is caused by the competing processes of non-linear Kelvin-Helmholtz instability driven by sheared plasma flows and the gradient drift instability process which operates in the presence of dawn-dusk motion of arc structures. The integrated strength of this class of irregularities also exhibits marked increase with increasing solar activity presumably because the ambient plasma density over the polar cap is enhanced.

  11. 47 CFR 54.675 - Cap.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 3 2013-10-01 2013-10-01 false Cap. 54.675 Section 54.675 Telecommunication..., the Administrator shall implement a filing window period that treats all eligible health care providers filing within the window period as if their applications were simultaneously received. (3) (4)...

  12. H. cap alpha. in RS CVn binaries

    SciTech Connect

    Bopp, B.W.; Talcott, J.C.

    1980-01-01

    The 1976--78 results of a spectroscopic program to monitor H..cap alpha.. in several RS CVn-type binaries are reported. For six objects well observed over orbital phase, four (HR 4665, HR 5110, sigma Gem, Z Her) show H..cap alpha.. as an absorption feature having a constant ( +- 15%) equivalent width (EW). AR Lac exhibits an absorption profile also, but the EW varies by a factor of three due to partial filling by emission. This variation is sporadic and not phase dependent. The H..cap alpha.. feature in HK Lac shows the most extreme variation: normally seen as an absorption feature with variable EW, it has been observed as a pure emission feature on three spectrograms, showing a blueshift with respect to the photosphere of approx.50--100 km sec/sup -1/. On a single occasion HK Lac showed double H..cap alpha.. emission with a separation of the peaks of approx.300 km sec/sup -1/. These high velocity features are interpreted in terms of prominence-like structure in the atmosphere of the active star.

  13. Capping blowouts from Iran's 8-year war

    SciTech Connect

    Sayers, B. )

    1991-07-01

    Control well blown up by the Iraqi military were a 2 1/2 year legacy left the National Iranian Oil Co. at the end of this long conflict. This final installment of a 2-part series describes capping of the largest wind oil well.

  14. 21 CFR 884.5250 - Cervical cap.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Cervical cap. 884.5250 Section 884.5250 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES... collect menstrual flow or to aid artificial insemination. This generic type of device is not...

  15. Natural attenuation processes during in situ capping.

    PubMed

    Himmelheber, David W; Pennell, Kurt D; Hughes, Joseph B

    2007-08-01

    Chlorinated solvents are common groundwater contaminants that threaten surface water quality and benthic health when present in groundwater seeps. Aquatic sediments can act as natural biobarriers to detoxify chlorinated solvent plumes via reductive dechlorination. In situ sediment capping, a remedial technique in which clean material is placed at the sediment-water interface, may alter sedimentary natural attenuation processes. This research explores the potential of Anacostia River sediment to naturally attenuate chlorinated solvents under simulated capping conditions. Results of microcosm studies demonstrated that intrinsic dechlorination of dissolved-phase PCE to ethene was possible, with electron donor availability controlling microbial activity. A diverse microbial community was present in the sediment, including multiple Dehalococcoides strains indicated by the amplification of the reductive dehalogenases tceA, vcrA, and bvcA. An upflow column simulating a capped sediment bed subject to PCE-contaminated groundwater seepage lost dechlorination activity with time and only achieved complete dechlorination when microorganisms present in the sediment were provided electron donor. Increases in effluent chloroethene concentrations during the period of biostimulation were attributed to biologically enhanced desorption and the formation of less sorptive dechlorination products. These findings suggest that in situ caps should be designed to account for reductions in natural biobarrier reactivity and for the potential breakthrough of groundwater contaminants. PMID:17822095

  16. Shrinking ice caps in the spotlight.

    PubMed

    Gross, Michael

    2014-10-01

    From the disappearing sea ice of the Arctic to the thriving microbial communities in subglacial lakes of Antarctica, the Earth's ice caps have often made the news in recent months and years, and polar science has emerged as being crucial to our understanding of our planet's biology and climate. Michael Gross reports.

  17. 47 CFR 54.507 - Cap.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... yearly average GDP-CPI is determined, the Wireline Competition Bureau shall publish a public notice in... category one services, the Administrator, at the direction of the Wireline Competition Bureau, shall direct... notwithstanding the annual cap. The Chief, Wireline Competition Bureau, is delegated authority to determine...

  18. Science CAP: Curriculum Assistance Program. [Multimedia.

    ERIC Educational Resources Information Center

    DEMCO, Inc., Madison, WI.

    Science Curriculum Assistance Program (Science CAP(TM)) is a multimedia package developed to create a model for preserving classroom science activities that can be shared and customized by teachers. This program is designed to assist teachers in preparing classroom science activities for grades five through eight, and to foster an environment of…

  19. Natural attenuation processes during in situ capping.

    PubMed

    Himmelheber, David W; Pennell, Kurt D; Hughes, Joseph B

    2007-08-01

    Chlorinated solvents are common groundwater contaminants that threaten surface water quality and benthic health when present in groundwater seeps. Aquatic sediments can act as natural biobarriers to detoxify chlorinated solvent plumes via reductive dechlorination. In situ sediment capping, a remedial technique in which clean material is placed at the sediment-water interface, may alter sedimentary natural attenuation processes. This research explores the potential of Anacostia River sediment to naturally attenuate chlorinated solvents under simulated capping conditions. Results of microcosm studies demonstrated that intrinsic dechlorination of dissolved-phase PCE to ethene was possible, with electron donor availability controlling microbial activity. A diverse microbial community was present in the sediment, including multiple Dehalococcoides strains indicated by the amplification of the reductive dehalogenases tceA, vcrA, and bvcA. An upflow column simulating a capped sediment bed subject to PCE-contaminated groundwater seepage lost dechlorination activity with time and only achieved complete dechlorination when microorganisms present in the sediment were provided electron donor. Increases in effluent chloroethene concentrations during the period of biostimulation were attributed to biologically enhanced desorption and the formation of less sorptive dechlorination products. These findings suggest that in situ caps should be designed to account for reductions in natural biobarrier reactivity and for the potential breakthrough of groundwater contaminants.

  20. Possible contemporary evaporites formation at the Martian Northern Polar Cap

    NASA Astrophysics Data System (ADS)

    Losiak, Anna; Czechowski, Leszek

    Evaporitic minerals are abundant on the surface of Mars (e.g., Wentworth et al. 2005, Velbel 2012, Clark and Van Hart 1981, Wang et al. 2006, Kuzmin et al. 2009), especially within the Circumpolar Dune Field and on the Northern Ice Cap itself (e.g., Langevin et al., 2005, Roach et al. 2007, Horgan et al. 2009, Masse et al. 2010, 2012). Most of their proposed formation mechanisms require significant amounts of liquid water and are thus not possible under current Martian conditions (Arvidson et al. 2006, Andrews-Hanna et al. 2007, Fishbaugh et al. 2007, Szynkiewicz et al. 2010). Some authors have considered the potential role of ice and ice- or snowmelt-related alteration in the weathering of Martian materials (e.g., Catling et al. 2006, Zolotov and Mironenko 2007, Niles and Michalski 2009, Masse et al. 2010). However, none of those studies discussed details of the process leading to the formation of the evaporites or the timing of the processes. The aim of this paper is to model numerically if the current radiant heating is sufficient to melt a thin layer of ice surrounding a single dust grain exposed within the south facing side of the Martian North Polar Cap trench. The results of our initial study suggest that for dust grains with basaltic properties and ice with low values of coefficient of heat conduction, and solar constant = 492 W/m2 liquid water may exist below a dust grain for up to 4 hours a sol. This suggest that contemporary evaporites formation on Martian Polar Cap is possible.

  1. Nuclear waste vitrification efficiency: cold cap reactions

    SciTech Connect

    Hrma, Pavel R.; Kruger, Albert A.; Pokorny, Richard

    2012-12-15

    The cost and schedule of nuclear waste treatment and immobilization are greatly affected by the rate of glass production. Various factors influence the performance of a waste-glass melter. One of the most significant, and also one of the least understood, is the process of batch melting. Studies are being conducted to gain fundamental understanding of the batch reactions, particularly those that influence the rate of melting, and models are being developed to link batch makeup and melter operation to the melting rate. Batch melting takes place within the cold cap, i.e., a batch layer floating on the surface of molten glass. The conversion of batch to glass consists of various chemical reactions, phase transitions, and diffusion-controlled processes. These include water evaporation (slurry feed contains as high as 60% water), gas evolution, the melting of salts, the formation of borate melt, reactions of borate melt with molten salts and with amorphous oxides (Fe2O3 and Al2O3), the formation of intermediate crystalline phases, the formation of a continuous glass-forming melt, the growth and collapse of primary foam, and the dissolution of residual solids. To this list we also need to add the formation of secondary foam that originates from molten glass but accumulates on the bottom of the cold cap. This study presents relevant data obtained for a high-level-waste melter feed and introduces a one-dimensional (1D) mathematical model of the cold cap as a step toward an advanced three-dimensional (3D) version for a complete model of the waste glass melter. The 1D model describes the batch-to-glass conversion within the cold cap as it progresses in a vertical direction. With constitutive equations and key parameters based on measured data, and simplified boundary conditions on the cold-cap interfaces with the glass melt and the plenum space of the melter, the model provides sensitivity analysis of the response of the cold cap to the batch makeup and melter conditions

  2. NUCLEAR WASTE VITRIFICATION EFFICIENCY COLD CAP REACTIONS

    SciTech Connect

    KRUGER AA; HRMA PR; POKORNY R

    2011-07-29

    The cost and schedule of nuclear waste treatment and immobilization are greatly affected by the rate of glass production. Various factors influence the performance of a waste-glass melter. One of the most significant, and also one of the least understood, is the process of batch melting. Studies are being conducted to gain fundamental understanding of the batch reactions, particularly those that influence the rate of melting, and models are being developed to link batch makeup and melter operation to the melting rate. Batch melting takes place within the cold cap, i.e., a batch layer floating on the surface of molten glass. The conversion of batch to glass consists of various chemical reactions, phase transitions, and diffusion-controlled processes. These include water evaporation (slurry feed contains as high as 60% water), gas evolution, the melting of salts, the formation of borate melt, reactions of borate melt with molten salts and with amorphous oxides (Fe{sub 2}O{sub 3} and Al{sub 2}O{sub 3}), the formation of intermediate crystalline phases, the formation of a continuous glass-forming melt, the growth and collapse of primary foam, and the dissolution of residual solids. To this list we also need to add the formation of secondary foam that originates from molten glass but accumulates on the bottom of the cold cap. This study presents relevant data obtained for a high-level-waste melter feed and introduces a one-dimensional (1D) mathematical model of the cold cap as a step toward an advanced three-dimensional (3D) version for a complete model of the waste glass melter. The 1D model describes the batch-to-glass conversion within the cold cap as it progresses in a vertical direction. With constitutive equations and key parameters based on measured data, and simplified boundary conditions on the cold-cap interfaces with the glass melt and the plenum space of the melter, the model provides sensitivity analysis of the response of the cold cap to the batch makeup

  3. Rapidly Melting Ice Caps of Northern Baffin Island: Insights From Cosmogenic and Conventional Radiocarbon Dating

    NASA Astrophysics Data System (ADS)

    Anderson, R. K.; Miller, G. H.; Briner, J. P.; Lifton, N.; Devogel, S. B.

    2006-12-01

    The interior plateau of northern Baffin Island in the eastern Canadian Arctic is home to several small (< 50 km2) ice caps whose melt has been well recorded since 1949. Modern equilibrium line altitude (ELA) is well above all existing ice and a continuation of current climatic conditions will lead to the disappearance of all ice on the plateau in the future. Between 2000 and 2005, approximately 1 km2 of ice was lost per year, equivalent to ~1.3% of the total ice cover on the plateau. To put this current melt into a larger picture of ice-cap history on the plateau since deglaciation 6 ka, several techniques have been used in concert. The recent extent of the ice caps during the Little Ice Age can be estimated from the preservation of lichen trimlines across much of the plateau. These trimlines represent previous multi-year snow or ice cover and their aerial extent can be measured via satellite imagery. Based on these measurements, modern ice caps represent only ~3% of ice-cap extent during the Little Ice Age. Radiocarbon dating of moss, preserved beneath the ice caps due to their cold-based nature, suggests a sudden expansion of ice cover around 520 calendar years before present (cal BP), indicated by a mode of 7 dates of approximately this age. This coincides with a pulse of global volcanic activity; predicted cooling from increased aerosol loading may have triggered rapid ice-cap growth. However, dead moss emerging at three sites is more than 1000 years old, with a maximum age of 1326±15 cal BP, indicating that portions of the remaining ice caps have remained intact from more than 1000 years Further constraints on ice cap size are provided by 14C cosmogenic exposure dating. 14C concentrations in rocks at the modern ice margin are too low to be the result of continuous exposure since deglaciation followed by shielding for 500-1000 years by ice cover. Exposure history modeling indicates at least one additional prior period of ice cover of approximately 1000 years

  4. High-pressure jet cutters improve capping operations

    SciTech Connect

    Abel, L.W.; Campbell, P.J.; Bowden, J.R. Sr.

    1995-05-08

    Advances in abrasive cutting technology have improved the methods for removing damaged equipment and preparing wellheads for capping. This technology, much of which was refined during well control operations in Kuwait in 1991, can improve the safety and efficiency of capping jobs by cutting wellheads or casing quickly and cleanly. The majority of well control jobs involve one of three types of capping operations: capping to a flange, capping by installing a wellhead, or capping to a casing stub. Capping operations are often the first major step in regaining control of the well during blowout intervention. Proper planning of a capping operation must take into account the mass flow rate, combustible nature of the flow, well bore geometry, and operations in the post-capping phase of the project. The paper discusses capping vehicles, tree removal, jet cutters, capping to a flange, capping to a stub, swallowing the stub, spin-on technique, capping on fire, stinging, offshore blowouts, firefighting, pollution control, intervention equipment, and rig removal.

  5. MSA-capped gold nanoparticle-supported alumina for the determination of Pb and Cd in various environmental water samples

    NASA Astrophysics Data System (ADS)

    Kiran, K.

    2014-11-01

    2-Mercaptosuccinic acid (MSA)-capped gold nanoparticles (GNPs) were used to determine the level of concentration of lead and cadmium metals in various environmental samples. Alumina-coated MSA-capped GNPs easily remove lead and cadmium present in various samples. The absorbance spectrum was obtained at 547 nm. Effects of pH, reagent concentration, interferences, were studied. This method is simple, selective and successfully applied for the determination of lead and cadmium species in various water samples collected in and around four industries.

  6. Low flammability cap-sensitive flexible explosive composition

    DOEpatents

    Wagner, Martin G.

    1992-01-14

    A cap-sensitive flexible explosive composition of reduced flammability is provided by incorporating a finely divided, cap-sensitive explosive in a flame resistant polymeric binder system which contains a compatible flame retardant material.

  7. Taxon interactions control the distributions of cryoconite bacteria colonizing a High Arctic ice cap.

    PubMed

    Gokul, Jarishma K; Hodson, Andrew J; Saetnan, Eli R; Irvine-Fynn, Tristram D L; Westall, Philippa J; Detheridge, Andrew P; Takeuchi, Nozomu; Bussell, Jennifer; Mur, Luis A J; Edwards, Arwyn

    2016-08-01

    Microbial colonization of glacial ice surfaces incurs feedbacks which affect the melting rate of the ice surface. Ecosystems formed as microbe-mineral aggregates termed cryoconite locally reduce ice surface albedo and represent foci of biodiversity and biogeochemical cycling. Consequently, greater understanding the ecological processes in the formation of functional cryoconite ecosystems upon glacier surfaces is sought. Here, we present the first bacterial biogeography of an ice cap, evaluating the respective roles of dispersal, environmental and biotic filtration occurring at local scales in the assembly of cryoconite microbiota. 16S rRNA gene amplicon semiconductor sequencing of cryoconite colonizing a Svalbard ice cap coupled with digital elevation modelling of physical parameters reveals the bacterial community is dominated by a ubiquitous core of generalist taxa, with evidence for a moderate pairwise distance-decay relationship. While geographic position and melt season duration are prominent among environmental predictors of community structure, the core population of taxa appears highly influential in structuring the bacterial community. Taxon co-occurrence network analysis reveals a highly modular community structured by positive interactions with bottleneck taxa, predominantly Actinobacteria affiliated to isolates from soil humus. In contrast, the filamentous cyanobacterial taxon (assigned to Leptolyngbya/Phormidesmis pristleyi) which dominates the community and binds together granular cryoconite are poorly connected to other taxa. While our study targeted one ice cap, the prominent role of generalist core taxa with close environmental relatives across the global cryosphere indicate discrete roles for cosmopolitan Actinobacteria and Cyanobacteria as respective keystone taxa and ecosystem engineers of cryoconite ecosystems colonizing ice caps. PMID:27261672

  8. Multi-stage polar cap convection response to enhanced interplanetary driving

    NASA Astrophysics Data System (ADS)

    Sandholt, Per Even; Farrugia, Charlie; Andalsvik, Yngvild

    2013-04-01

    In two case studies we investigate the response of ionospheric convection to enhanced magnetopause reconnection rate leading to repetitive substorm activity. Our interplanetary (IP) driver is coronal mass ejections (CMEs). The aim is to estimate the cross-polar cap potential (CPCP) at high temporal resolution (1 min). To achieve this, we use a method where we combine direct measurements of the CPCP from satellite ion drift data, which have limited temporal coverage, with high-resolution (1 min) ground observations of equivalent convection in the central polar cap, obtained from the polar cap index in the northern hemisphere (PCN). In our CPCP estimates we distinguish between contributions from different sectors of the polar cap (center and periphery) as well as from the dayside and nightside sources. The polar cap (PC) periphery is characterized by channels of enhanced antisunward flows, which are particularly pronounced in the winter hemisphere. These flow channels are continuously monitored by ground data from the IMAGE chain of magnetometers in Svalbard - Scandinavia - Finland. They are discussed as stages in the evolution of the Dungey flux circulation cycle driven by both dayside and nightside sources. Following Siscoe et al. (2011) we distinguish between two stages of the evolution of the convection response, i.e., an initial transient phase, and a subsequent persistent phase.

  9. Correlation of Pectin Methylesterase Activity in Root Caps of Pea with Root Border Cell Separation.

    PubMed Central

    Stephenson, M. B.; Hawes, M. C.

    1994-01-01

    We tested predictions of the hypothesis that pectin methylesterase in the root cap plays a role in cell wall solubilization leading to separation of root border cells from the root tip. Root cap pectin methylesterase activity was detected only in species that release large numbers of border cells daily. In pea (Pisum sativum) root caps, enzyme activity is correlated with border cell separation during development: 6-fold more activity occurs during border cell separation than after cell separation is complete. Higher levels of enzyme activity are restored by experimental induction of border cell separation. A corresponding increase in transcription of a gene encoding root cap pectin methylesterase precedes the increase in enzyme activity. A dramatic increase in the level of soluble, de-esterified pectin in the root tip also is correlated with pectin methylesterase activity during border cell development. This increase in acidic, de-esterified pectin during development occurs in parallel with a decrease in cell wall/apoplastic pH of cells in the periphery of the root cap. PMID:12232366

  10. Considerations for the direct pulp capping procedure in primary teeth: a review of the literature.

    PubMed

    Kopel, H M

    1992-01-01

    In reviewing the various studies concerning the direct pulp capping procedure in primary teeth, using rigid criteria for case selection and procedure appears to insure a significant amount of success. It is acknowledged that vital primary pulp tissue is capable of healing without resorting to complete pulpectomy, although statistically direct pulp capping has been found to be less successful in primary teeth than indirect pulp therapy or coronal amputation (pulpotomy). To achieve success for direct pulp capping in primary teeth, the considerations involve: selecting teeth with minimal or no clinical signs of pulpal inflammation; or pretreating the carious tooth with a sedative restoration before excavating the caries; disinfecting the cavity floor; enlarging the actual exposure, and flushing out dentinal debris with mild solutions; controlling bleeding by not allowing a clot to form; placing a hard-set, CaOH material over the exposure, followed by a fast-setting, zinc oxide-eugenol cement to achieve a hermetic seal; and lastly, placing a stainless steel crown to minimize microleakage and prevent a fractured or defective restoration. These procedural steps can hardly ensure complete success in direct pulp capping of a primary tooth; but, based on the many cited investigations in this review, a significant amount of success can be expected without resorting more frequently to invasive techniques. Surely the evidence presented leading to the feasibility of direct pulp capping in primary teeth merits further investigations, before dogmatically rejecting this procedure of pulp therapy. PMID:1583199

  11. Gamma-Ray Pulsar Light Curves in Offset Polar Cap Geometry

    NASA Technical Reports Server (NTRS)

    Harding, Alice K.; DeCesar, Megan; Miller, M. Coleman

    2011-01-01

    Recent studies have shown that gamma-ray pulsar light curves are very sensitive to the geometry of the pulsar magnetic field. Pulsar magnetic field geometries, such as the retarded vacuum dipole and force-free magnetospheres, used to model high-energy light curves have distorted polar caps that are offset from the magnetic axis in the direction opposite to rotation. Since this effect is due to the sweepback of field lines near the light cylinder, offset polar caps are a generic property of pulsar magnetospheres and their effects should be included in gamma-ray pulsar light curve modeling. In slot gap models (having two-pole caustic geometry), the offset polar caps cause a strong azimuthal asymmetry of the particle acceleration around the magnetic axis. We have studied the effect of the offset polar caps in both retarded vacuum dipole and force-free geometry on the model high-energy pulse profile. We find that. corn pared to the profile:-; derived from :-;ymmetric caps, the flux in the pulse peaks, which are caustics formed along the trailing magnetic field lines. increases significantly relative to the off-peak emission. formed along leading field lines. The enhanced contrast produces greatly improved slot gap model fits to Fermi pulsar light curves like Vela, which show very little off-peak emIssIon.

  12. Interaction between Ca/sup + +/-channel antagonists and. cap alpha. /sub 2/-adrenergic receptors in rabbit ileal cell membrane

    SciTech Connect

    Homeidan, F.R.; Wicks, J.; Cusolito, S.; El-Sabban, M.E.; Sharp, G.W.G.; Donowitz, M.

    1986-03-05

    An interaction between Ca/sup + +/-channel antagonists and the ..cap alpha../sub 2/-adrenergic receptor on active electrolyte transport was demonstrated in rabbit ileum. Clonidine, an ..cap alpha../sub 2/-agonist, stimulated NaCl absorption apparently by Ca/sup + +/-channel antagonism since it inhibited /sup 45/Ca/sup + +/ uptake across the basolateral membrane and decreased total ileal calcium content. This stimulation was inhibited by the Ca/sup + +/-channel antagonists dl- and l-verapamil and cadmium but not by nifedipine. The binding of /sup 3/H-yohimbine, a specific ..cap alpha../sub 2/-adrenergic antagonist, was studied on purified ileal cell membranes using a rapid filtration technique. dl-Verapamil and Cd/sup + +/ inhibited the specific binding of /sup 3/H-yohimbine over the same concentration range in which they affected transport. In contrast, nifedipine had no effect on binding, just as it had no effect on clonidine-stimulated NaCl absorption. These data demonstrate that there is an interaction between Ca/sup + +/-channels and ..cap alpha../sub 2/-adrenergic receptors in ileal basolateral membranes. Some Ca/sup + +/-channel antagonists alter ..cap alpha../sub 2/-adrenergic binding to the receptor and ..cap alpha../sub 2/-agonist binding leads to changes in Ca/sup + +/ entry. A close spatial relationship between the Ca/sup + +/-channel and the ..cap alpha../sub 2/-receptor could explain the data.

  13. Core layering

    NASA Astrophysics Data System (ADS)

    Jacobson, S. A.; Rubie, D. C.; Hernlund, J. W.; Morbidelli, A.

    2015-12-01

    We have created a planetary accretion and differentiation model that self-consistently builds and evolves Earth's core. From this model, we show that the core grows stably stratified as the result of rising metal-silicate equilibration temperatures and pressures, which increases the concentrations of light element impurities into each newer core addition. This stable stratification would naturally resist convection and frustrate the onset of a geodynamo, however, late giant impacts could mechanically mix the distinct accreted core layers creating large homogenous regions. Within these regions, a geodynamo may operate. From this model, we interpret the difference between the planetary magnetic fields of Earth and Venus as a difference in giant impact histories. Our planetary accretion model is a numerical N-body integration of the Grand Tack scenario [1]—the most successful terrestrial planet formation model to date [2,3]. Then, we take the accretion histories of Earth-like and Venus-like planets from this model and post-process the growth of each terrestrial planet according to a well-tested planetary differentiation model [4,5]. This model fits Earth's mantle by modifying the oxygen content of the pre-cursor planetesimals and embryos as well as the conditions of metal-silicate equilibration. Other non-volatile major, minor and trace elements included in the model are assumed to be in CI chondrite proportions. The results from this model across many simulated terrestrial planet growth histories are robust. If the kinetic energy delivered by larger impacts is neglected, the core of each planet grows with a strong stable stratification that would significantly impede convection. However, if giant impact mixing is very efficient or if the impact history delivers large impacts late, than the stable stratification can be removed. [1] Walsh et al. Nature 475 (2011) [2] O'Brien et al. Icarus 223 (2014) [3] Jacobson & Morbidelli PTRSA 372 (2014) [4] Rubie et al. EPSL 301

  14. 31 CFR 50.90 - Cap on annual liability.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 31 Money and Finance: Treasury 1 2014-07-01 2014-07-01 false Cap on annual liability. 50.90 Section 50.90 Money and Finance: Treasury Office of the Secretary of the Treasury TERRORISM RISK INSURANCE PROGRAM Cap on Annual Liability § 50.90 Cap on annual liability. Pursuant to Section 103 of the Act,...

  15. mRNA capping: biological functions and applications.

    PubMed

    Ramanathan, Anand; Robb, G Brett; Chan, Siu-Hong

    2016-09-19

    The 5' m7G cap is an evolutionarily conserved modification of eukaryotic mRNA. Decades of research have established that the m7G cap serves as a unique molecular module that recruits cellular proteins and mediates cap-related biological functions such as pre-mRNA processing, nuclear export and cap-dependent protein synthesis. Only recently has the role of the cap 2'O methylation as an identifier of self RNA in the innate immune system against foreign RNA has become clear. The discovery of the cytoplasmic capping machinery suggests a novel level of control network. These new findings underscore the importance of a proper cap structure in the synthesis of functional messenger RNA. In this review, we will summarize the current knowledge of the biological roles of mRNA caps in eukaryotic cells. We will also discuss different means that viruses and their host cells use to cap their RNA and the application of these capping machineries to synthesize functional mRNA. Novel applications of RNA capping enzymes in the discovery of new RNA species and sequencing the microbiome transcriptome will also be discussed. We will end with a summary of novel findings in RNA capping and the questions these findings pose. PMID:27317694

  16. 31 CFR 50.90 - Cap on annual liability.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 31 Money and Finance: Treasury 1 2013-07-01 2013-07-01 false Cap on annual liability. 50.90 Section 50.90 Money and Finance: Treasury Office of the Secretary of the Treasury TERRORISM RISK INSURANCE PROGRAM Cap on Annual Liability § 50.90 Cap on annual liability. Pursuant to Section 103 of the Act,...

  17. mRNA capping: biological functions and applications.

    PubMed

    Ramanathan, Anand; Robb, G Brett; Chan, Siu-Hong

    2016-09-19

    The 5' m7G cap is an evolutionarily conserved modification of eukaryotic mRNA. Decades of research have established that the m7G cap serves as a unique molecular module that recruits cellular proteins and mediates cap-related biological functions such as pre-mRNA processing, nuclear export and cap-dependent protein synthesis. Only recently has the role of the cap 2'O methylation as an identifier of self RNA in the innate immune system against foreign RNA has become clear. The discovery of the cytoplasmic capping machinery suggests a novel level of control network. These new findings underscore the importance of a proper cap structure in the synthesis of functional messenger RNA. In this review, we will summarize the current knowledge of the biological roles of mRNA caps in eukaryotic cells. We will also discuss different means that viruses and their host cells use to cap their RNA and the application of these capping machineries to synthesize functional mRNA. Novel applications of RNA capping enzymes in the discovery of new RNA species and sequencing the microbiome transcriptome will also be discussed. We will end with a summary of novel findings in RNA capping and the questions these findings pose.

  18. mRNA capping: biological functions and applications

    PubMed Central

    Ramanathan, Anand; Robb, G. Brett; Chan, Siu-Hong

    2016-01-01

    The 5′ m7G cap is an evolutionarily conserved modification of eukaryotic mRNA. Decades of research have established that the m7G cap serves as a unique molecular module that recruits cellular proteins and mediates cap-related biological functions such as pre-mRNA processing, nuclear export and cap-dependent protein synthesis. Only recently has the role of the cap 2′O methylation as an identifier of self RNA in the innate immune system against foreign RNA has become clear. The discovery of the cytoplasmic capping machinery suggests a novel level of control network. These new findings underscore the importance of a proper cap structure in the synthesis of functional messenger RNA. In this review, we will summarize the current knowledge of the biological roles of mRNA caps in eukaryotic cells. We will also discuss different means that viruses and their host cells use to cap their RNA and the application of these capping machineries to synthesize functional mRNA. Novel applications of RNA capping enzymes in the discovery of new RNA species and sequencing the microbiome transcriptome will also be discussed. We will end with a summary of novel findings in RNA capping and the questions these findings pose. PMID:27317694

  19. 31 CFR 50.90 - Cap on annual liability.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 31 Money and Finance: Treasury 1 2010-07-01 2010-07-01 false Cap on annual liability. 50.90 Section 50.90 Money and Finance: Treasury Office of the Secretary of the Treasury TERRORISM RISK INSURANCE PROGRAM Cap on Annual Liability § 50.90 Cap on annual liability. Pursuant to Section 103 of the Act,...

  20. 31 CFR 50.90 - Cap on annual liability.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 31 Money and Finance: Treasury 1 2011-07-01 2011-07-01 false Cap on annual liability. 50.90 Section 50.90 Money and Finance: Treasury Office of the Secretary of the Treasury TERRORISM RISK INSURANCE PROGRAM Cap on Annual Liability § 50.90 Cap on annual liability. Pursuant to Section 103 of the Act,...

  1. 31 CFR 50.90 - Cap on annual liability.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 31 Money and Finance: Treasury 1 2012-07-01 2012-07-01 false Cap on annual liability. 50.90 Section 50.90 Money and Finance: Treasury Office of the Secretary of the Treasury TERRORISM RISK INSURANCE PROGRAM Cap on Annual Liability § 50.90 Cap on annual liability. Pursuant to Section 103 of the Act,...

  2. An Historical Look at a Contemporary Question: The Cervical Cap.

    ERIC Educational Resources Information Center

    Zimmet, Judy A.; Reagan, Patricia A.

    1986-01-01

    The history of the use of cervical caps as a birth control method is recounted in the areas of (1) revival of the cervical cap; (2) repopularization of the cervical cap; (3) empirical research; (4) nonbehavioral factors; (5) behavioral problems; and (6) health problems. (CB)

  3. Leading Democratically

    ERIC Educational Resources Information Center

    Brookfield, Stephen

    2010-01-01

    Democracy is the most venerated of American ideas, the one for which wars are fought and people die. So most people would probably agree that leaders should be able to lead well in a democratic society. Yet, genuinely democratic leadership is a relative rarity. Leading democratically means viewing leadership as a function or process, rather than…

  4. Bioavailability of Hydrophobic Organic Compounds in Thin-Layered Capped Sediments

    PubMed Central

    Meric, Dogus; Alshawabkeh, Akram N.; Shine, James P.; Sheahan, Thomas C.

    2014-01-01

    The effect of a thin sand capping layer (7.5 cm) on the bioavailability of hydrophobic organic compounds (HOCs, i.e., PCBs and naphthalene) was studied using oligochaete worms, and the results compared to previously obtained bioavailability tests with a reactive core mat (RCM) cap. The study investigated the difference in HOC concentration in worms exposed to: a) a grab sample of sediment used as sampled for PCBs and spiked for PAHs; b) an initially clean mixture of sand and organic matter (biouptake layer) directly overlying the sediment; and c) the biouptake layer placed on top of the RCM-capped sediment. Benchscale experiments were performed to induce pore fluid flux through the sediment and into the overlying layer(s). Principal component analysis (PCA) was used to assess PCB homolog group concentrations. Results indicate that the thin sand cap alone reduced the average bioavailability of PCBs by a factor of 100 compared to direct exposure, but had no effect on the bioavailability of naphthalene. However, worms exposed to the RCM-protected biouptake layer show virtually the same HOC concentrations as those in the background worm samples, indicating effective isolation by the RCM. PMID:24374187

  5. Volcanic unrest primed by ice cap melting: A case study of Snæfellsjökull volcano, Western Iceland

    NASA Astrophysics Data System (ADS)

    Bakker, Richard; Lupi, Matteo; Frehner, Marcel; Berger, Julien; Fuchs, Florian

    2014-05-01

    The most dramatic effect of global warming is the water level rise due to rapid melting of ice sheets. In addition, recent studies suggest that accelerated glacial retreat and associated lithospheric relaxation may enhance upwelling of magmatic fluids through the crust. Here, we investigate whether, also at short geological timescales, shallow magmatic systems may be affected by rapid melting of ice caps. As a case study, we chose the Snæfellsjökull volcanic system in western Iceland, whose ice cap is rapidly melting with 1.25 m(w.e.)/year. To investigate the role of deglaciation in promoting volcanic unrest we use a cross-disciplinary approach integrating geophysical field data, laboratory rheological rock tests, and numerical finite-element analysis. Initial results from seismic data acquisition and interpretation in 2011 show seismic activity (occasionally in swarm sequences) at around a depth range of 8-13 km, indicating the presence of a magmatic reservoir in the crust. In addition, a temporary seismic network of 21 broad-band stations has been deployed in spring 2013 and continuously collected data for several months, which will help better constrain the subsurface geometry. During summer 2013 we collected samples of Tertiary basaltic bedrock from the flanks of Snæfellsjökull, which we assume to be representative for the subsurface volcanic system. Cores drilled from these samples were tri-axially deformed in a Paterson-type apparatus at a constant strain rate of 10-5 s-1, a confining pressure of 50 MPa (i.e. ~2 km depth), and a temperature ranging from 200 °C to 1000 °C (i.e. various proximities to magma chamber). From the obtained stress-strain curves the static Young's modulus is calculated to be around 35 (±2) GPa, which is not significantly influenced by increasing temperatures up to 800 °C. Beyond the elastic domain, cataclastic shear bands develop, accommodating up to 7% strain before brittle failure. The subsurface geometrical constraints from

  6. Some core contested concepts.

    PubMed

    Chomsky, Noam

    2015-02-01

    Core concepts of language are highly contested. In some cases this is legitimate: real empirical and conceptual issues arise. In other cases, it seems that controversies are based on misunderstanding. A number of crucial cases are reviewed, and an approach to language is outlined that appears to have strong conceptual and empirical motivation, and to lead to conclusions about a number of significant issues that differ from some conventional beliefs.

  7. Late Holocene expansion of Istorvet ice cap, Liverpool Land, east Greenland

    NASA Astrophysics Data System (ADS)

    Lowell, Thomas V.; Hall, Brenda L.; Kelly, Meredith A.; Bennike, Ole; Lusas, Amanda R.; Honsaker, William; Smith, Colby A.; Levy, Laura B.; Travis, Scott; Denton, George H.

    2013-03-01

    The Greenland Ice Sheet is undergoing dynamic changes that will have global implications if they continue into the future. In this regard, an understanding of how the ice sheet responded to past climate changes affords a baseline for anticipating future behavior. Small, independent ice caps adjacent to the Greenland Ice Sheet (hereinafter called "local ice caps") are sensitive indicators of the response of Greenland ice-marginal zones to climate change. Therefore, we reconstructed late Holocene ice-marginal fluctuations of the local Istorvet ice cap in east Greenland, using radiocarbon dates of subfossil plants, 10Be dates of surface boulders, and analyses of sediment cores from both threshold and control lakes. During the last termination, the Istorvet ice cap had retreated close to its maximum Holocene position by ˜11,730 cal yr BP. Radiocarbon dates of subfossil plants exposed by recent recession of the ice margin indicate that the Istorvet cap was smaller than at present from AD 200 to AD 1025. Sediments from a threshold lake show no glacial input until the ice cap advanced to within 365 m of its Holocene maximum position by ˜AD 1150. Thereafter the ice cap remained at or close to this position until at least AD 1660. The timing of this, the most extensive of the Holocene, expansion is similar to that recorded at some glaciers in the Alps and in southern Alaska. However, in contrast to these other regions, the expansion in east Greenland at AD 1150 appears to have been very close to, if not at, a maximum Holocene value. Comparison of the Istorvet ice-cap fluctuations with Holocene glacier extents in Southern Hemisphere middle-to-high latitude locations on the Antarctic Peninsula and in the Andes and the Southern Alps suggests an out-of-phase relationship. If correct, this pattern supports the hypothesis that a bipolar see-saw of oceanic and/or atmospheric circulation during the Holocene produced asynchronous glacier response at some localities in the two

  8. The Phase Composition of Triton's Polar Caps.

    PubMed

    Duxbury, N S; Brown, R H

    1993-08-01

    Triton's polar caps are modeled as permanent nitrogen deposits hundreds of meters thick. Complex temperature variations on Triton's surface induce reversible transitions between the cubic and hexagonal phases of solid nitrogen, often with two coexisting propagating transition fronts. Subsurface temperature distributions are calculated using a two-dimensional thermal model with phase changes. The phase changes fracture the upper nitrogen layer, increasing its reflectivity and thus offering an explanation for the surprisingly high southern polar cap albedo (approximately 0.8) seen during the Voyager 2 flyby. The model has other implications for the phase transition phenomena on Triton, such as a plausible mechanism for the origin of geyser-like plume vent areas and a mechanism of energy transport toward them.

  9. The phase composition of Triton's polar caps

    NASA Technical Reports Server (NTRS)

    Duxbury, N. S.; Brown, R. H.

    1993-01-01

    Triton's polar caps are modeled as permanent nitrogen deposits hundreds of meters thick. Complex temperature variations on Triton's surface induce reversible transitions between the cubic and hexagonal phases of solid nitrogen, often with two coexisting propagating transition fronts. Subsurface temperature distributions are calculated using a two-dimensional thermal model with phase changes. The phase changes fracture the upper nitrogen layer, increasing its reflectivity and thus offering an explanation for the surprisingly high southern polar cap albedo (approximately 0.8) seen during the Voyager 2 flyby. The model has other implications for the phase transition phenomena on Triton, such as a plausible mechanism for the origin of geyser-like plume vent areas and a mechanism of energy transport toward them.

  10. The Phase Composition of Triton's Polar Caps.

    PubMed

    Duxbury, N S; Brown, R H

    1993-08-01

    Triton's polar caps are modeled as permanent nitrogen deposits hundreds of meters thick. Complex temperature variations on Triton's surface induce reversible transitions between the cubic and hexagonal phases of solid nitrogen, often with two coexisting propagating transition fronts. Subsurface temperature distributions are calculated using a two-dimensional thermal model with phase changes. The phase changes fracture the upper nitrogen layer, increasing its reflectivity and thus offering an explanation for the surprisingly high southern polar cap albedo (approximately 0.8) seen during the Voyager 2 flyby. The model has other implications for the phase transition phenomena on Triton, such as a plausible mechanism for the origin of geyser-like plume vent areas and a mechanism of energy transport toward them. PMID:17757213

  11. The phase composition of Triton's polar caps

    NASA Astrophysics Data System (ADS)

    Duxbury, N. S.; Brown, R. H.

    1993-08-01

    Triton's polar caps are modeled as permanent nitrogen deposits hundreds of meters thick. Complex temperature variations on Triton's surface induce reversible transitions between the cubic and hexagonal phases of solid nitrogen, often with two coexisting propagating transition fronts. Subsurface temperature distributions are calculated using a two-dimensional thermal model with phase changes. The phase changes fracture the upper nitrogen layer, increasing its reflectivity and thus offering an explanation for the surprisingly high southern polar cap albedo (approximately 0.8) seen during the Voyager 2 flyby. The model has other implications for the phase transition phenomena on Triton, such as a plausible mechanism for the origin of geyser-like plume vent areas and a mechanism of energy transport toward them.

  12. Innovative endodontic therapy for anti-inflammatory direct pulp capping of permanent teeth with a mature apex

    PubMed Central

    Komabayashi, Takashi; Zhu, Qiang

    2010-01-01

    Direct pulp capping is a treatment of an exposed vital pulp with a dental material to facilitate the formation of reparative dentin and maintenance of vital pulp. It has been studied as an alternate way to avoid vital pulp extirpation. However, the success rate of pulp capping is much lower than that of vital pulp extirpation. Therefore, direct pulp capping is currently considered controversial by many clinicians. To increase success rate, a critical need exists to develop new biologically-based therapeutics that reduce pulp inflammation, promote the continued formation of new dentin-pulp complex, and restore vitality by stimulating the regrowth of pulpal tissue. Bioengineered anti-inflammatory direct pulp capping materials, together with adhesive materials for leakage prevention, have great potential to improve the condition of the existing pulp from an inflamed to a non-inflamed status and lead to a high rate of long-term success. PMID:20416524

  13. Innovative endodontic therapy for anti-inflammatory direct pulp capping of permanent teeth with a mature apex.

    PubMed

    Komabayashi, Takashi; Zhu, Qiang

    2010-05-01

    Direct pulp capping is treatment of an exposed vital pulp with a dental material to facilitate the formation of reparative dentin and maintenance of vital pulp. It has been studied as an alternate way to avoid vital pulp extirpation. However, the success rate of pulp capping is much lower than that of vital pulp extirpation. Therefore, direct pulp capping is currently considered controversial by many clinicians. To increase the success rate, a critical need exists to develop new biologically based therapeutics that reduce pulp inflammation, promote the continued formation of new dentin-pulp complex, and restore vitality by stimulating the regrowth of pulpal tissue. Bioengineered anti-inflammatory direct pulp-capping materials, together with adhesive materials for leakage prevention, have great potential to improve the condition of the existing pulp from an inflamed to a noninflamed status and lead to a high rate of long-term success.

  14. Atomistic description of thiostannate-capped CdSe nanocrystals: retention of four-coordinate SnS4 motif and preservation of Cd-rich stoichiometry.

    PubMed

    Protesescu, Loredana; Nachtegaal, Maarten; Voznyy, Oleksandr; Borovinskaya, Olga; Rossini, Aaron J; Emsley, Lyndon; Copéret, Christophe; Günther, Detlef; Sargent, Edward H; Kovalenko, Maksym V

    2015-02-11

    Colloidal semiconductor nanocrystals (NCs) are widely studied as building blocks for novel solid-state materials. Inorganic surface functionalization, used to displace native organic capping ligands from NC surfaces, has been a major enabler of electronic solid-state devices based on colloidal NCs. At the same time, very little is known about the atomistic details of the organic-to-inorganic ligand exchange and binding motifs at the NC surface, severely limiting further progress in designing all-inorganic NCs and NC solids. Taking thiostannates (K4SnS4, K4Sn2S6, K6Sn2S7) as typical examples of chalcogenidometallate ligands and oleate-capped CdSe NCs as a model NC system, in this study we address these questions through the combined application of solution (1)H NMR spectroscopy, solution and solid-state (119)Sn NMR spectroscopy, far-infrared and X-ray absorption spectroscopies, elemental analysis, and by DFT modeling. We show that through the X-type oleate-to-thiostannate ligand exchange, CdSe NCs retain their Cd-rich stoichiometry, with a stoichiometric CdSe core and surface Cd adatoms serving as binding sites for terminal S atoms of the thiostannates ligands, leading to all-inorganic (CdSe)core[Cdm(Sn2S7)yK(6y-2m)]shell (taking Sn2S7(6-) ligand as an example). Thiostannates SnS4(4-) and Sn2S7(6-) retain (distorted) tetrahedral SnS4 geometry upon binding to NC surface. At the same time, experiments and simulations point to lower stability of Sn2S6(4-) (and SnS3(2-)) in most solvents and its lower adaptability to the NC surface caused by rigid Sn2S2 rings.

  15. Atomistic Description of Thiostannate-Capped CdSe Nanocrystals: Retention of Four-Coordinate SnS4 Motif and Preservation of Cd-Rich Stoichiometry

    PubMed Central

    2016-01-01

    Colloidal semiconductor nanocrystals (NCs) are widely studied as building blocks for novel solid-state materials. Inorganic surface functionalization, used to displace native organic capping ligands from NC surfaces, has been a major enabler of electronic solid-state devices based on colloidal NCs. At the same time, very little is known about the atomistic details of the organic-to-inorganic ligand exchange and binding motifs at the NC surface, severely limiting further progress in designing all-inorganic NCs and NC solids. Taking thiostannates (K4SnS4, K4Sn2S6, K6Sn2S7) as typical examples of chalcogenidometallate ligands and oleate-capped CdSe NCs as a model NC system, in this study we address these questions through the combined application of solution 1H NMR spectroscopy, solution and solid-state 119Sn NMR spectroscopy, far-infrared and X-ray absorption spectroscopies, elemental analysis, and by DFT modeling. We show that through the X-type oleate-to-thiostannate ligand exchange, CdSe NCs retain their Cd-rich stoichiometry, with a stoichiometric CdSe core and surface Cd adatoms serving as binding sites for terminal S atoms of the thiostannates ligands, leading to all-inorganic (CdSe)core[Cdm(Sn2S7)yK(6y-2m)]shell (taking Sn2S76– ligand as an example). Thiostannates SnS44– and Sn2S76– retain (distorted) tetrahedral SnS4 geometry upon binding to NC surface. At the same time, experiments and simulations point to lower stability of Sn2S64– (and SnS32–) in most solvents and its lower adaptability to the NC surface caused by rigid Sn2S2 rings. PMID:25597625

  16. Process for making surfactant capped nanocrystals

    DOEpatents

    Alivisatos, A Paul; Rockenberger, Joerg

    2002-01-01

    Disclosed is a process for making surfactant capped nanocrystals of transition metal oxides. The process comprises reacting a metal cupferron complex of the formula M Cup, wherein M is a transition metal, and Cup is a cupferron, with a coordinating surfactant, the reaction being conducted at a temperature ranging from about 250 to about 300 C., for a period of time sufficient to complete the reaction.

  17. Morphology of Mars North Polar Ice Cap

    NASA Technical Reports Server (NTRS)

    Zwally, H. J.; Fountain, A.; Kargel, J.; Kouvaris, L.; Lewis, K.; MacAyeal, D.; Pfeffer, T.; Saba, J. L.

    2000-01-01

    The northern ice cap of Mars consists of a parabolic dome centered within 13 km of the pole, plus an arm-like ridge extending from the dome between about 135 and 225 east. Chasma Boreale lies between the dome and the extended ridge. The base of the dome is approximately elliptical with a major axis of 1100 km along the 90 east to 270 east direction and minor axis of 700 km along zero east to 180 deg. The heights of the dome and the extended ridge are respectively 2900 inches and 1700 inches above the surrounding basin. Least-squares fitting of a parabola through height profiles of the dome along longitudes 90 deg to 270 deg and zero deg to 180 deg gives an elliptic-paraboloid equation for the dome: Z(m) = 2800 - [(X-x)(exp 2)/113.6] - [(Y-y)(exp 2)/50.3], where X is the 90 deg to 270 deg axis, x = 9.90 km, y = 13.32 km, and the slightly-different fitted heights for the two axes are averaged. The center of the dome is shifted 13.32 km from the pole along zero deg longitude and 9.90 km along 90 deg longitude. Typical mean surface slopes on the ice cap are the order of 1/100 (0.6 deg), A small central portion of the cap, about 100 km by 200 km, extends in elevation about 200 inches above the parabolic shape of the cap. Additional information is contained in the original extended abstract.

  18. Mars South Polar Cap 'Fingerprint' Terrain

    NASA Technical Reports Server (NTRS)

    2000-01-01

    This picture is illuminated by sunlight from the upper left.

    Some portions of the martian south polar residual cap have long, somewhat curved troughs instead of circular pits. These appear to form in a layer of material that may be different than that in which 'swiss cheese' circles and pits form, and none of these features has any analog in the north polar cap or elsewhere on Mars. This picture shows the 'fingerprint' terrain as a series of long, narrow depressions considered to have formed by collapse and widening by sublimation of ice. Unlike the north polar cap, the south polar region stays cold enough in summer to retain frozen carbon dioxide. Viking Orbiter observations during the late 1970s showed that very little water vapor comes off the south polar cap during summer, indicating that any frozen water that might be there remains solid throughout the year.

    This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image was obtained in early southern spring on August 4, 1999. It shows an area 3 x 5 kilometers (1.9 x 3.1 miles) at a resolution of about 7.3 meters (24 ft) per pixel. Located near 86.0oS, 53.9oW.

    Malin Space Science Systems and the California Institute of Technology built the MOC using spare hardware from the Mars Observer mission. MSSS operates the camera from its facilities in San Diego, CA. The Jet Propulsion Laboratory's Mars Surveyor Operations Project operates the Mars Global Surveyor spacecraft with its industrial partner, Lockheed Martin Astronautics, from facilities in Pasadena, CA and Denver, CO.

  19. Thermal barrier and support for nuclear reactor fuel core

    DOEpatents

    Betts, Jr., William S.; Pickering, J. Larry; Black, William E.

    1987-01-01

    A thermal barrier/core support for the fuel core of a nuclear reactor having a metallic cylinder secured to the reactor vessel liner and surrounded by fibrous insulation material. A top cap is secured to the upper end of the metallic cylinder that locates and orients a cover block and post seat. Under normal operating conditions, the metallic cylinder supports the entire load exerted by its associated fuel core post. Disposed within the metallic cylinder is a column of ceramic material, the height of which is less than that of the metallic cylinder, and thus is not normally load bearing. In the event of a temperature excursion beyond the design limits of the metallic cylinder and resulting in deformation of the cylinder, the ceramic column will abut the top cap to support the fuel core post.

  20. Lobe cell convection and polar cap precipitation

    NASA Astrophysics Data System (ADS)

    Eriksson, S.; Peria, W. J.; Bonnell, J. W.; Su, Y.-J.; Ergun, R. E.; Tung, Y.-K.; Parks, G. K.; Carlson, C. W.

    2003-05-01

    The characteristic electric and magnetic field signature of lobe cells as observed by the low-altitude FAST satellite in 55 dawn-dusk passes are compared with Polar ultraviolet images of polar cap auroral activity. Initial results from 34 events of UV image coverage suggest that there is an intimate coupling between the sunward convection flow of the lobe cell and transpolar auroral arcs or diffuse polar cap precipitation in ˜62% of these cases. However, in some cases where the field signatures are suggestive of lobe cell convection, there is no detectable particle precipitation either in Polar UVI or the FAST data sets. Moreover, the presence of lobe cells coincide with UV data intensifications in the premidnight 2000-2400 MLT sector and/or the postnoon 1500 MLT region in ˜59% of all cases with UVI coverage. The magnetic local time dependence of the lobe cells and polar cap precipitation on the interplanetary magnetic field (IMF) are examined using the upstream Wind monitor. The relative importance of the IMF By and Bz components are investigated and compared with the predictions of the antiparallel merging model and strongly suggests a connection with the magnetospheric sash, as is further implied by the mapping of magnetic field lines using the [2002] (T01) model. It was also noted that a majority of lobe cell events occurred during enhanced AE index substorm-like conditions and that generally stronger AE indices are measured for stronger IMF By magnitudes during these events.

  1. Lobe Cell Convection and Polar cap Precipitation

    NASA Astrophysics Data System (ADS)

    Eriksson, S.; Peria, W. J.; Su, Y.; Ergun, R. E.; Tung, Y.; Parks, G.; Carlson, C. W.

    2002-12-01

    The characteristic electric and magnetic field signature of lobe cells as observed by the low-altitude FAST satellite are compared with Polar ultraviolet images of polar cap auroral activity. Initial results from 55 events suggest that there is an intimate coupling between the sunward convection flow of the lobe cell and transpolar auroral arcs or diffuse polar cap precipitation. Moreover, the presence of lobe cells coincide with UV data intensifications in the premidnight 2100-2400 MLT sector and/or the postnoon 1500 MLT region in ~54% of all cases with UVI coverage. The magnetic local time dependence of the lobe cells and polar cap precipitation on the interplanetary magnetic field (IMF) are examined using the upstream Wind monitor. The relative importance of the IMF By and Bz components are investigated and compared with the predictions of the antiparallel merging model and strongly suggests a connection with the magnetospheric sash, as is further implied by the mapping of magnetic field lines using the Tsyganenko [2002] (T01) model. It was also noted that a majority of events occurred during enhanced AE index substorm-like conditions and that generally stronger AE indices are measured for stronger IMF By magnitudes.

  2. MycoCAP - Mycobacterium Comparative Analysis Platform

    PubMed Central

    Choo, Siew Woh; Ang, Mia Yang; Dutta, Avirup; Tan, Shi Yang; Siow, Cheuk Chuen; Heydari, Hamed; Mutha, Naresh V. R.; Wee, Wei Yee; Wong, Guat Jah

    2015-01-01

    Mycobacterium spp. are renowned for being the causative agent of diseases like leprosy, Buruli ulcer and tuberculosis in human beings. With more and more mycobacterial genomes being sequenced, any knowledge generated from comparative genomic analysis would provide better insights into the biology, evolution, phylogeny and pathogenicity of this genus, thus helping in better management of diseases caused by Mycobacterium spp.With this motivation, we constructed MycoCAP, a new comparative analysis platform dedicated to the important genus Mycobacterium. This platform currently provides information of 2108 genome sequences of at least 55 Mycobacterium spp. A number of intuitive web-based tools have been integrated in MycoCAP particularly for comparative analysis including the PGC tool for comparison between two genomes, PathoProT for comparing the virulence genes among the Mycobacterium strains and the SuperClassification tool for the phylogenic classification of the Mycobacterium strains and a specialized classification system for strains of Mycobacterium abscessus. We hope the broad range of functions and easy-to-use tools provided in MycoCAP makes it an invaluable analysis platform to speed up the research discovery on mycobacteria for researchers. Database URL: http://mycobacterium.um.edu.my PMID:26666970

  3. Comparison of Detector Technologies for CAPS

    NASA Technical Reports Server (NTRS)

    Stockum, Jana L.

    2005-01-01

    In this paper, several different detectors are examined for use in a Comet/Asteroid Protection System (CAPS), a conceptual study for a possible future space-based system. Each detector will be examined for its future (25 years or more in the future) ability to find and track near-Earth Objects (NEOs) from a space-based detection platform. Within the CAPS study are several teams of people who each focus on different aspects of the system concept. This study s focus is on detection devices. In particular, evaluations on the following devices have been made: charge-coupled devices (CCDs), charge-injected devices (CIDs), superconducting tunneling junctions (STJs), and transition edge sensors (TESs). These devices can be separated into two main categories; the first category includes detectors that are currently being widely utilized, such as CCDs and CIDs. The second category includes experimental detectors, such as STJs and TESs. After the discussion of the detectors themselves, there will be a section devoted to the explicit use of these detectors with CAPS.

  4. Protein synthesis in geostimulated root caps

    NASA Technical Reports Server (NTRS)

    Feldman, L. J.

    1982-01-01

    A study is presented of the processes occurring in the root cap of corn which are requisite for the formation of root cap inhibitor and which can be triggered or modulated by both light and gravity. The results of this study indicate the importance of protein synthesis for light-induced gravitropic bending in roots. Root caps in which protein synthesis is prevented are unable to induce downward bending. This suggests that light acts by stimulating proteins which are necessary for the translation of the gravitropic stimulus into a growth response (downward bending). The turnover of protein with time was also examined in order to determine whether light acts by stimulating the synthesis of unique proteins required for downward growth. It is found that auxin in combination with light allows for the translation of the gravitropic stimulus into a growth response at least in part through the modification of protein synthesis. It is concluded that unique proteins are stimulated by light and are involved in promoting the downward growth in roots which are responding to gravity.

  5. MycoCAP - Mycobacterium Comparative Analysis Platform.

    PubMed

    Choo, Siew Woh; Ang, Mia Yang; Dutta, Avirup; Tan, Shi Yang; Siow, Cheuk Chuen; Heydari, Hamed; Mutha, Naresh V R; Wee, Wei Yee; Wong, Guat Jah

    2015-01-01

    Mycobacterium spp. are renowned for being the causative agent of diseases like leprosy, Buruli ulcer and tuberculosis in human beings. With more and more mycobacterial genomes being sequenced, any knowledge generated from comparative genomic analysis would provide better insights into the biology, evolution, phylogeny and pathogenicity of this genus, thus helping in better management of diseases caused by Mycobacterium spp.With this motivation, we constructed MycoCAP, a new comparative analysis platform dedicated to the important genus Mycobacterium. This platform currently provides information of 2108 genome sequences of at least 55 Mycobacterium spp. A number of intuitive web-based tools have been integrated in MycoCAP particularly for comparative analysis including the PGC tool for comparison between two genomes, PathoProT for comparing the virulence genes among the Mycobacterium strains and the SuperClassification tool for the phylogenic classification of the Mycobacterium strains and a specialized classification system for strains of Mycobacterium abscessus. We hope the broad range of functions and easy-to-use tools provided in MycoCAP makes it an invaluable analysis platform to speed up the research discovery on mycobacteria for researchers. Database URL: http://mycobacterium.um.edu.my.

  6. LEAD STUDIES

    PubMed Central

    Aub, Joseph C.; Reznikoff, Paul; Smith, Dorothea E.

    1924-01-01

    It appears, from the investigations in other laboratories, that the anemia observed in cases of lead poisoning is due to destruction of blood rather than to diminished production of blood. The method of poisoning cells in vitro with lead was adopted in order to study this phenomenon, and distinct effects were thereby obtained, even when only 0.001 mg. of lead is added to approximately 5 billion washed red corpuscles. In order to obtain optimum results the usual dosage employed was ten times this or 0.01 mg. per 5 billion cells. The following changes were observed in cells so treated. 1. Such a marked increase in the resistance to hypotonic salt solution develops that complete hemolysis does not occur until the cells are exposed to a saline solution of 0.05 per cent. Untreated cells are completely hemolyzed in 0.25 or 0.225 per cent saline. 2. This reaction is quantitative and varies with the concentration of lead used. Under the conditions of our experiments this phenomenon seems to be unique. The effects of arsenic are very slight in comparison. 3. While from this reaction it may be concluded that lead increases cellular resistance, it also appears that it shortens the life of blood cells. This may be demonstrated by the much more rapid appearance of hemolysis than normal when the cells are merely allowed to stand in Ringer solution of any dilution. 4. In rabbits with acute lead poisoning these same phenomena may be noted in vivo. 5. Both phenomena may be changed in vitro by varying the time and temperature of the reaction and the concentration of lead, as Fici has already pointed out. 6. If normal cells stand in Ringer solution for 6 hours something diffuses into the solution which largely reduces the action of lead. After repeated washing these cells react with lead in the usual manner. 7. Small amounts of serum react with lead and eliminate its effects. Red blood cells, treated with a mixture of lead and blood serum, show normal hemolysis in hypotonic salt

  7. What Lies Below a Martian Ice Cap

    NASA Technical Reports Server (NTRS)

    2008-01-01

    [figure removed for brevity, see original site] Click on image for larger annotated version

    This image (top) taken by the Shallow Radar instrument on NASA's Mars Reconnaissance Orbiter reveals the layers of ice, sand and dust that make up the north polar ice cap on Mars. It is the most detailed look to date at the insides of this ice cap. The colored map below the radar picture shows the topography of the corresponding Martian terrain (red and white represent higher ground, and green and yellow lower).

    The radar image reveals four never-before-seen thick layers of ice and dust separated by layers of nearly pure ice. According to scientists, these thick ice-free layers represent approximately one-million-year-long cycles of climate change on Mars caused by variations in the planet's tilted axis and its eccentric orbit around the sun. Adding up the entire stack of ice gives an estimated age for the north polar ice cap of about 4 million years a finding that agrees with previous theoretical estimates. The ice cap is about 2 kilometers (1.2 miles) thick.

    The radar picture also shows that the boundary between the ice layers and the surface of Mars underneath is relatively flat (bottom white line on the right). This implies that the surface of Mars is not sagging, or bending, under the weight of the ice cap and this, in turn, suggests that the planet's lithosphere, a combination of the crust and the strong parts of the upper mantle, is thicker than previously thought.

    A thicker lithosphere on Mars means that temperatures increase more gradually with depth toward the interior. Temperatures warm enough for water to be liquid are therefore deeper than previously thought. Likewise, if liquid water does exist in aquifers below the surface of Mars, and if there are any organisms living in that water, they would have to be located deeper in the planet.

    The topography data are from Mars Orbiter Laser Altimeter, which was flown on NASA's Mars Global

  8. Cap buckling as a potential mechanism of atherosclerotic plaque vulnerability.

    PubMed

    Abdelali, Maria; Reiter, Steven; Mongrain, Rosaire; Bertrand, Michel; L'Allier, Philippe L; Kritikou, Ekaterini A; Tardif, Jean-Claude

    2014-04-01

    Plaque rupture in atherosclerosis is the primary cause of potentially deadly coronary events, yet about 40% of ruptures occur away from the plaque cap shoulders and cannot be fully explained with the current biomechanical theories. Here, cap buckling is considered as a potential destabilizing factor which increases the propensity of the atherosclerotic plaque to rupture and which may also explain plaque failure away from the cap shoulders. To investigate this phenomenon, quasistatic 2D finite element simulations are performed, considering the salient geometrical and nonlinear material properties of diverse atherosclerotic plaques over the range of physiological loads. The numerical results indicate that buckling may displace the location of the peak von Mises stresses in the deflected caps. Plaque buckling, together with its deleterious effects is further observed experimentally in plaque caps using a physical model of deformable mock coronary arteries with fibroatheroma. Moreover, an analytical approach combining quasistatic equilibrium equations with the Navier-Bresse formulas is used to demonstrate the buckling potential of a simplified arched slender cap under intraluminal pressure and supported by foundations. This analysis shows that plaque caps - calcified, fibrotic or cellular - may buckle in specific undulated shapes once submitted to critical loads. Finally, a preliminary analysis of intravascular ultrasonography recordings of patients with atherosclerotic coronary arteries corroborates the numerical, experimental and theoretical findings and shows that various plaque caps buckle in vivo. By displacing the sites of high stresses in the plaque cap, buckling may explain the atherosclerotic plaque cap rupture at various locations, including cap shoulders.

  9. Purification, characterization, and immunofluorescence localization of Saccharomyces cerevisiae capping protein.

    PubMed

    Amatruda, J F; Cooper, J A

    1992-06-01

    Capping protein binds the barbed ends of actin filaments and nucleates actin filament assembly in vitro. We purified capping protein from Saccharomyces cervisiae. One of the two subunits is the product of the CAP2 gene, which we previously identified as the gene encoding the beta subunit of capping protein based on its sequence similarity to capping protein beta subunits in chicken and Dictyostelium (Amatruda, J. F., J. F. Cannon, K. Tatchell, C. Hug, and J. A. Cooper. 1990. Nature (Lond.) 344:352-354). Yeast capping protein has activity in critical concentration and low-shear viscometry assays consistent with barbed-end capping activity. Like chicken capping protein, yeast capping protein is inhibited by PIP2. By immunofluorescence microscopy yeast capping protein colocalizes with cortical actin spots at the site of bud emergence and at the tips of growing buds and shmoos. In contrast, capping protein does not colocalize with actin cables or with actin rings at the site of cytokinesis. PMID:1315784

  10. Di-μ-oxo dimetal core of Mn(IV) and Ti(IV) as a linker between two chiral salen complexes leading to the stereoselective formation of different M- and P-helical structures.

    PubMed

    Kurahashi, Takuya; Hada, Masahiko; Fujii, Hiroshi

    2014-01-21

    Because of restricted rotational freedom along the metal-metal axis, a di-μ-oxo dimetal core could be an excellent building block to create dinuclear compounds with well-defined stereochemistry, but their stereoselective synthesis remains a challenge. We herein report the formation of di-μ-oxo dimanganese(IV) complexes with tetradentate salen ligands bearing different degrees of steric bulk, in order to study stereochemical aspects of the dimerization reaction that potentially generates multiple stereoisomers. X-ray crystallography shows that the di-μ-oxo dimanganese(IV) complex with salen, where salen is (R,R)-N,N'-bis(3,5-di-tert-butylsalicylidene)-1,2-cyclohexanediamine, adopts a unique structure in which two salen complexes are arranged in an M-helical fashion. According to the solution study using (1)H, (2)H NMR, and circular dichroism spectroscopies, the dimerization reaction is highly diastereoselective in the presence of the tert-butyl group at the 3/3' position as a determinant steric factor. In contrast, the di-μ-oxo dititanium(IV) complex with the same salen ligand was previously reported to afford an opposite P-helical dimer. The present DFT study clarifies that a less-covalent Ti-O bonding causes a distortion of the di-μ-oxo dititanium(IV) core structure, generating a completely different framework for interligand interaction. The present study provides a solid basis to understand the stereochemistry for the formation of the di-μ-oxo dimetal core.

  11. Antiatherogenic effect of Caps HT2, a herbal Ayurvedic medicine formulation.

    PubMed

    Mary, N K; Babu, B H; Padikkala, J

    2003-01-01

    The antiatherogenic effect of a herbal formulation, Caps HT2, was evaluated as antioxidant, anticoagulant, platelet antiaggregatory, lipoprotein lipase releasing, anti-inflammatory and hypolipidaemic activity in rats. The formulation contained the methanolic extracts of selected parts of plants, Commiphora mukul, Allium sativum, Plumbago indica, Semecarpus anacardium, Hemidesmus indicus, Terminalia arjuna, Tinospora cordifolia, Withania somnifera and Ocimum sanctum. The formulation, Caps HT2 was found to scavenge superoxide and hydroxyl radicals; the IC50 required being 55.0 and 610.0 microg/ml respectively. The lipid peroxidation was found inhibited (50%) by 48.5 microg/ml of Caps HT2. The intravenous administration of the formulation (5 mg/kg) delayed the plasma recalcification time in rabbits and enhanced the release of lipoprotein lipase enzyme significantly (p < 0.001). The formulation also inhibited ADP induced platelet aggregation in vitro, which was comparable to commercial heparin. The anti-inflammatory action of the formulation was significant (p < 0.001) with acute and chronic inflammations induced by carrageenan and formalin respectively in rats. The hypolipidaemic effect of Caps HT2 was significant (p < 0.001) with the administration of the formulation, in diet-induced hyperlipidaemia of rats for a period of 30 days. Oral administration of the formulation, Caps HT2 (100, 200, 300 and 400 mg/kg) significantly raised HDL cholesterol levels. The atherogenic index and the reduction in body weight were significant indicating the effectiveness against hyperlipidaemia and obesity. All these results revealed the therapeutic potential of Caps HT2 against vascular intimal damage and atherogenesis leading to various types of cardiovascular problems. PMID:13678230

  12. LRRCE: a leucine-rich repeat cysteine capping motif unique to the chordate lineage

    PubMed Central

    Park, Hosil; Huxley-Jones, Julie; Boot-Handford, Ray P; Bishop, Paul N; Attwood, Teresa K; Bella, Jordi

    2008-01-01

    Background The small leucine-rich repeat proteins and proteoglycans (SLRPs) form an important family of regulatory molecules that participate in many essential functions. They typically control the correct assembly of collagen fibrils, regulate mineral deposition in bone, and modulate the activity of potent cellular growth factors through many signalling cascades. SLRPs belong to the group of extracellular leucine-rich repeat proteins that are flanked at both ends by disulphide-bonded caps that protect the hydrophobic core of the terminal repeats. A capping motif specific to SLRPs has been recently described in the crystal structures of the core proteins of decorin and biglycan. This motif, designated as LRRCE, differs in both sequence and structure from other, more widespread leucine-rich capping motifs. To investigate if the LRRCE motif is a common structural feature found in other leucine-rich repeat proteins, we have defined characteristic sequence patterns and used them in genome-wide searches. Results The LRRCE motif is a structural element exclusive to the main group of SLRPs. It appears to have evolved during early chordate evolution and is not found in protein sequences from non-chordate genomes. Our search has expanded the family of SLRPs to include new predicted protein sequences, mainly in fishes but with intriguing putative orthologs in mammals. The chromosomal locations of the newly predicted SLRP genes would support the large-scale genome or gene duplications that are thought to have occurred during vertebrate evolution. From this expanded list we describe a new class of SLRP sequences that could be representative of an ancestral SLRP gene. Conclusion Given its exclusivity the LRRCE motif is a useful annotation tool for the identification and classification of new SLRP sequences in genome databases. The expanded list of members of the SLRP family offers interesting insights into early vertebrate evolution and suggests an early chordate evolutionary

  13. Ecotoxicology: Lead

    USGS Publications Warehouse

    Scheuhammer, A.M.; Beyer, W.N.; Schmitt, C.J.; Jorgensen, Sven Erik; Fath, Brian D.

    2008-01-01

    Lead (Pb) is a naturally occurring metallic element; trace concentrations are found in all environmental media and in all living things. However, certain human activities, especially base metal mining and smelting; combustion of leaded gasoline; the use of Pb in hunting, target shooting, and recreational angling; the use of Pb-based paints; and the uncontrolled disposal of Pb-containing products such as old vehicle batteries and electronic devices have resulted in increased environmental levels of Pb, and have created risks for Pb exposure and toxicity in invertebrates, fish, and wildlife in some ecosystems.

  14. ASM LabCap's contributions to disease surveillance and the International Health Regulations (2005).

    PubMed

    Specter, Steven; Schuermann, Lily; Hakiruwizera, Celestin; Sow, Mah-Séré Keita

    2010-01-01

    The revised International Health Regulations [IHR(2005)], which requires the Member States of the World Health Organization (WHO) to develop core capacities to detect, assess, report, and respond to public health threats, is bringing new challenges for national and international surveillance systems. As more countries move toward implementation and/or strengthening of their infectious disease surveillance programs, the strengthening of clinical microbiology laboratories becomes increasingly important because they serve as the first line responders to detect new and emerging microbial threats, re-emerging infectious diseases, the spread of antibiotic resistance, and the possibility of bioterrorism. In fact, IHR(2005) Core Capacity #8, "Laboratory", requires that laboratory services be a part of every phase of alert and response.Public health laboratories in many resource-constrained countries require financial and technical assistance to build their capacity. In recognition of this, in 2006, the American Society for Microbiology (ASM) established an International Laboratory Capacity Building Program, LabCap, housed under the ASM International Board. ASM LabCap utilizes ASM's vast resources and its membership's expertise-40,000 microbiologists worldwide-to strengthen clinical and public health laboratory systems in low and low-middle income countries. ASM LabCap's program activities align with HR(2005) by building the capability of resource-constrained countries to develop quality-assured, laboratory-based information which is critical to disease surveillance and the rapid detection of disease outbreaks, whether they stem from natural, deliberate or accidental causes.ASM LabCap helps build laboratory capacity under a cooperative agreement with the U.S. Centers for Disease Control and Prevention (CDC) and under a sub-contract with the Program for Appropriate Technology in Health (PATH) funded by the United States Agency for International Development (USAID

  15. ASM LabCap's contributions to disease surveillance and the International Health Regulations (2005).

    PubMed

    Specter, Steven; Schuermann, Lily; Hakiruwizera, Celestin; Sow, Mah-Séré Keita

    2010-01-01

    The revised International Health Regulations [IHR(2005)], which requires the Member States of the World Health Organization (WHO) to develop core capacities to detect, assess, report, and respond to public health threats, is bringing new challenges for national and international surveillance systems. As more countries move toward implementation and/or strengthening of their infectious disease surveillance programs, the strengthening of clinical microbiology laboratories becomes increasingly important because they serve as the first line responders to detect new and emerging microbial threats, re-emerging infectious diseases, the spread of antibiotic resistance, and the possibility of bioterrorism. In fact, IHR(2005) Core Capacity #8, "Laboratory", requires that laboratory services be a part of every phase of alert and response.Public health laboratories in many resource-constrained countries require financial and technical assistance to build their capacity. In recognition of this, in 2006, the American Society for Microbiology (ASM) established an International Laboratory Capacity Building Program, LabCap, housed under the ASM International Board. ASM LabCap utilizes ASM's vast resources and its membership's expertise-40,000 microbiologists worldwide-to strengthen clinical and public health laboratory systems in low and low-middle income countries. ASM LabCap's program activities align with HR(2005) by building the capability of resource-constrained countries to develop quality-assured, laboratory-based information which is critical to disease surveillance and the rapid detection of disease outbreaks, whether they stem from natural, deliberate or accidental causes.ASM LabCap helps build laboratory capacity under a cooperative agreement with the U.S. Centers for Disease Control and Prevention (CDC) and under a sub-contract with the Program for Appropriate Technology in Health (PATH) funded by the United States Agency for International Development (USAID

  16. Apparatus and method for transferring coil leads from a partially assembled stator to a lead finishing assembly

    SciTech Connect

    Moser, K.W.

    1988-02-09

    This patent describes a method for transferring coil leads from a partially assembled dynamoelectric stator core to a lead finishing assembly in an apparatus for assembling coils into a stator core. The apparatus includes a stator pallet having lead retaining means thereon, and lead capturing means for catching the leads. The lead capturing means are movable between the lead finishing assembly and the pallet. The method comprises the steps of: moving the lead capturing means adjacent the lead retaining means; capturing a lead; retracting the capturing means to a lead transferring position adjacent the lead finishing assembly; and transferring the lead.

  17. Tetraethyl lead

    Integrated Risk Information System (IRIS)

    Tetraethyl lead ; CASRN 78 - 00 - 2 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogenic Ef

  18. cap alpha. -2 adrenergic receptor: a radiohistochemical study

    SciTech Connect

    Unnerstall, J.R.

    1984-01-01

    ..cap alpha..-2 adrenergic agents have been shown to influence blood pressure, heart rate and other physiological and behavioral functions through interactions with adrenergic pathways within the central nervous system. Pharmacologically relevant ..cap alpha..-1 adrenergic receptors were biochemically characterized and radiohistochemically analyzed in intact tissue sections of the rat and human central nervous system. The anatomical distribution of the ..cap alpha..-2 receptors, labeled with the agonist (/sup 3/H)para-aminoclonidine, verified the concept that ..cap alpha..-2 receptors are closely associated with adrenergic nerve terminals and that ..cap alpha..-2 agents can influence autonomic and endocrine function through an action in the central nervous system. Since ..cap alpha..-2 agonists can influence sympathetic outflow, ..cap alpha..-2 binding sites were closely analyzed in the intermediolateral cell column of the thoracic spinal cord. The transport of putative presynaptic ..cap alpha..-2 binding sites in the rat sciatic nerve was analyzed by light microscopic radiohistochemical techniques. Finally, in intact tissue section of the rat central nervous system, the biochemical characteristics of (/sup 3/H)rauwolscine binding were analyzed. Data were also shown which indicates that the synthetic ..cap alpha..-2 antagonist (/sup 3/H)RX781094 also binds to ..cap alpha..-2 receptors with high-affinity. Further, the distribution of (/sup 3/H)RX781094 binding sites in the rat central nervous system was identical to the distribution seen when using (/sup 3/H)para-aminoclonidine.

  19. Phosphogypsum capping depth affects revegetation and hydrology in Western Canada.

    PubMed

    Jackson, Mallory E; Naeth, M Anne; Chanasyk, David S; Nichol, Connie K

    2011-01-01

    Phosphogypsum (PG), a byproduct of phosphate fertilizer manufacturing, is commonly stacked and capped with soil at decommissioning. Shallow (0, 8, 15, and 30 cm) and thick (46 and 91 cm) sandy loam caps on a PG stack near Fort Saskatchewan, Alberta, Canada, were studied in relation to vegetation establishment and hydrologic properties. Plant response was evaluated over two growing seasons for redtop ( L.), slender wheatgrass ( (Link) Malte ex H.F. Lewis), tufted hairgrass ( (L.) P. Beauv.), and sheep fescue ( L.) and for a mix of these grasses with alsike clover ( L.). Water content below the soil-PG interface was monitored with time-domain reflectometry probes, and leachate water quantity and quality at a depth of 30 cm was measured using lysimeters. Vegetation responded positively to all cap depths relative to bare PG, with few significant differences among cap depths. Slender wheatgrass performed best, and tufted hairgrass performed poorly. Soil caps <1 m required by regulation were sufficient for early revegetation. Soil water fluctuated more in shallow than in thick caps, and water content was generally between field capacity and wilting point regardless of cap depth. Water quality was not affected by cap depths ≤30 cm. Leachate volumes at 30 cm from distinct rainfall events were independent of precipitation amount and cap depth. The study period had lower precipitation than normal, yet soil caps were hospitable for plant growth in the first 2 yr of establishment.

  20. IAA transport in corn roots includes the root cap

    SciTech Connect

    Hasenstein, K.H. )

    1989-04-01

    In earlier reports we concluded that auxin is the growth regulator that controls gravicurvature in roots and that the redistribution of auxin occurs within the root cap. Since other reports did not detect auxin in the root cap, we attempted to confirm the IAA does move through the cap. Agar blocks containing {sup 3}H-IAA were applied to the cut surface of 5 mm long apical segments of primary roots of corn (mo17xB73). After 30 to 120 min radioactivity (RA) of the cap and root tissue was determined. While segments suspended in water-saturated air accumulated very little RA in the cap, application of 0.5 {mu}1 of dist. water to the cap (=controls) increased RA of the cap dramatically. Application to the cap of 0.5 {mu}1 of sorbitol or the Ca{sup 2+} chelator EGTA reduced cap RA to 46% and 70% respectively compared to water, without affecting uptake. Control root segments gravireacted faster than non-treated or osmoticum or EGTA treated segments. The data indicate that both the degree of hydration and calcium control the amount of auxin moving through the cap.

  1. Genetic ablation of root cap cells in Arabidopsis

    NASA Technical Reports Server (NTRS)

    Tsugeki, R.; Fedoroff, N. V.

    1999-01-01

    The root cap is increasingly appreciated as a complex and dynamic plant organ. Root caps sense and transmit environmental signals, synthesize and secrete small molecules and macromolecules, and in some species shed metabolically active cells. However, it is not known whether root caps are essential for normal shoot and root development. We report the identification of a root cap-specific promoter and describe its use to genetically ablate root caps by directing root cap-specific expression of a diphtheria toxin A-chain gene. Transgenic toxin-expressing plants are viable and have normal aerial parts but agravitropic roots, implying loss of root cap function. Several cell layers are missing from the transgenic root caps, and the remaining cells are abnormal. Although the radial organization of the roots is normal in toxin-expressing plants, the root tips have fewer cytoplasmically dense cells than do wild-type root tips, suggesting that root meristematic activity is lower in transgenic than in wild-type plants. The roots of transgenic plants have more lateral roots and these are, in turn, more highly branched than those of wild-type plants. Thus, root cap ablation alters root architecture both by inhibiting root meristematic activity and by stimulating lateral root initiation. These observations imply that the root caps contain essential components of the signaling system that determines root architecture.

  2. Quantifying Solar Wind-Polar Cap Interactions

    NASA Astrophysics Data System (ADS)

    Urban, K. D.; Gerrard, A. J.; Lanzerotti, L. J.; Weatherwax, A. T.; Huang, Y.

    2015-12-01

    It is well known that the solar wind is a major driver of ultra-low frequency [ULF] power at ground locations from low to high latitudes. However, due to the scarcity of deep polar cap magnetometer sites, it is not clear when, where, or if this is true deep inside the polar cap on open field lines where interplanetary magnetic field [IMF] ULF waves could possibly be directly detected. Given recent observations of very large Joule heating estimates from DMSP data, together with the large heating reported by the CHAMP satellite, it is important to understand the degree to which ULF waves in the solar wind can directly cause such heating. Using a time series of lagged correlation sequences ("dynamic correlograms") between GSM Bz ULF power (computed via data obtained from NASA's Advanced Composition Explorer [ACE] ahead of Earth in the solar wind) and the horizontal ULF power (H^2=N^2+E^2) from ground-based magnetometers in Earth's southern polar cap, we investigate the direct penetration of ULF waves from the solar wind into the polar ionosphere during a gamut of space weather conditions at a distributed network of Automated Geophysical Observatories [AGOs] in Antarctica. To infer causation, a predicted lag correlation maximum at each time step is computed by simply dividing the associated distance of ACE from Earth by the concurrent bulk solar wind speed. This technique helps parse out direct penetration of solar wind ULF waves from other sources (e.g., via leakage from closed field line resonances due to the bulk solar wind plasma viscously interacting at dawn/dusk flanks inducing Kelvin-Helmholtz instabilities [KHI] or compressional modes induced by impulses in solar wind dynamic pressure). The identified direct-penetrating ULF waves are related to the DMSP-derived Poynting fluxes by regression analysis, and conclusions are drawn for the importance of the ULF source for the measured heating.

  3. Underwater Christmas tree cap and lockdown apparatus

    SciTech Connect

    Best, M.J.A.

    1983-09-20

    A cap is disclosed for an underwater Christmas tree having locking probes to lock down the operating rods of a connector connecting the Christmas tree to an underwater wellhead housing. The tops of the operating rods are housed within hollow canisters at the top of the Christmas tree. The cap includes a body having circumferentially disposed locking dogs housed therein for engagement with the top of the Christmas tree. The dogs are actuated by a cam ring which telescopically receive the body and has a tapered surface for sliding over a correlatively tapered surface on each of the dogs. The body includes a metal gasket seal for sealing engagement with the top of the Christmas tree, and seals are provided between the cam ring and body. The cap has downwardly extending locking probes which extend telescopically into the canisters above the operating rods. The locking probes each include a housing and a releasable tubular piston slidably disposed in the housing. The piston is biased in a downward direction, and is held in a cocked or loaded raised position prior to release by a trigger held in engagement with the piston and housing a pin on a running tool telescopically slidably disposed in the piston. The piston is released by removal of the pin, which cams the trigger out of engagement with the housing. Upon release the piston is biased into engagement with the rod. The piston is provided with locking dogs which engage the walls of the housing and prevent upward movement of the piston and rod after release of the piston.

  4. MARK II end cap calorimeter electronics

    SciTech Connect

    Jared, R.C.; Haggerty, J.S.; Herrup, D.A.; Kirsten, F.A.; Lee, K.L.; Olson, S.R.; Wood, D.R.

    1985-10-01

    An end cap calorimeter system has been added to the MARK II detector in preparation for its use at the SLAC Linear Collider. The calorimeter uses 8744 rectangular proportional counter tubes. This paper describes the design features of the data acquisition electronics that has been installed on the calorimeter. The design and use of computer-based test stands for the amplification and signal-shaping components is also covered. A portion of the complete system has been tested in a beam at SLAC. In these initial tests, using only the calibration provided by the test stands, a resolution of 18%/..sqrt..E was achieved.

  5. Comparative behavior of membrane protein-antibody complexes on motile fibroblasts: implications for a mechanism of capping

    PubMed Central

    1990-01-01

    A characteristic feature of fibroblast locomotory activity is the rearward transport across the leading lamella of various materials used to mark the cell surface. The two processes most frequently invoked as explanations for this transport phenomenon, called capping, are (a) retrograde membrane flow arising from directed membrane insertion and (b) rearward cortical cytoskeletal flow arising from cytoskeletal assembly and contraction. The retrograde lipid flow hypothesis, the most current form of the membrane flow scheme, makes explicit predictions about the movement of membrane proteins subjected to the postulated rearward lipid flow. Several of these predictions were tested by comparing the behavior of four membrane proteins, Pgp-1, Thy- 1, H-2, and influenza HA0, identified by fluorescent antibodies. With the exception of Pgp-1, these proteins were uniformly distributed under nonaggregated conditions but were capped when aggregated into patches. In contrast, Pgp-1 was capped in similar time frames in both nonaggregated and aggregated states where the lateral diffusion coefficients were very different. Furthermore, the capping behavior of two tagged membrane proteins was markedly different yet both had similar diffusion coefficients. The results from these tests disprove the bulk membrane flow hypothesis and are at odds with explicit predictions of the retrograde lipid flow hypothesis for the mechanism of capping. This work, therefore, supports the alternative cytoskeletal- based mechanism for driving capping. Requirements for coupling cytoskeletal movement to membrane components are discussed. PMID:2277071

  6. Fat4/Dchs1 signaling between stromal and cap mesenchyme cells influences nephrogenesis and ureteric bud branching.

    PubMed

    Mao, Yaopan; Francis-West, Philippa; Irvine, Kenneth D

    2015-08-01

    Formation of the kidney requires reciprocal signaling among the ureteric tubules, cap mesenchyme and surrounding stromal mesenchyme to orchestrate complex morphogenetic events. The protocadherin Fat4 influences signaling from stromal to cap mesenchyme cells to regulate their differentiation into nephrons. Here, we characterize the role of a putative binding partner of Fat4, the protocadherin Dchs1. Mutation of Dchs1 in mice leads to increased numbers of cap mesenchyme cells, which are abnormally arranged around the ureteric bud tips, and impairment of nephron morphogenesis. Mutation of Dchs1 also reduces branching of the ureteric bud and impairs differentiation of ureteric bud tip cells into trunk cells. Genetically, Dchs1 is required specifically within cap mesenchyme cells. The similarity of Dchs1 phenotypes to stromal-less kidneys and to those of Fat4 mutants implicates Dchs1 in Fat4-dependent stroma-to-cap mesenchyme signaling. Antibody staining of genetic mosaics reveals that Dchs1 protein localization is polarized within cap mesenchyme cells, where it accumulates at the interface with stromal cells, implying that it interacts directly with a stromal protein. Our observations identify a role for Fat4 and Dchs1 in signaling between cell layers, implicate Dchs1 as a Fat4 receptor for stromal signaling that is essential for kidney development, and establish that vertebrate Dchs1 can be molecularly polarized in vivo. PMID:26116666

  7. The "baseball cap orthosis": a simple solution for dropped head syndrome.

    PubMed

    Fast, Avital; Thomas, Mark A

    2008-01-01

    Dropped head syndrome (DHS) is a well-recognized condition characterized by gradual sagging of the head. At the extreme, the condition may lead to a "chin on chest deformity" where the chin rests on the chest wall and the patient is unable to look straight ahead. Dropped head syndrome tends to develop in patients with severe weakness of the neck extensors. Various neuromuscular disorders and surgical procedures may compromise the stability of the cervical spine and lead to this disorder. The condition may severely compromise the patient's quality of life and result in significant disability. A simple device-the "baseball cap orthosis"-was developed to help patients maintain their head in the upright position. Two patients with DHS who were provided with the baseball cap orthosis are presented.

  8. Strontium Isotopes of Gaskiers Cap Carbonate, Avalon, Newfoundland: Sequential Digestion Aids Interpretation of Petrologic Complexity

    NASA Astrophysics Data System (ADS)

    Tang, T.; Raub, T. D.; Wang, Z.

    2013-12-01

    Strontium isotope chemostratigraphy in limestones appear to track a near monotonic rising trend from the tail of the breakup of the supercontinent Rodinia at ~750 Ma into the latest Ediacaran Period at ~ 550 Ma (Halverson et al., 2007). This offers a potentially powerful tool to date carbonates occurring within this time period of stepwise environmental oxidation. Furthermore, aspects of the Snowball Earth hypothesis predict that some magnitude of 87Sr/86Sr excursions of seawater is expected at multiple intervals during this time, because balancing influences from prolonged synglacial hydrothermal input in entombed oceans, deglacial freshwater plumes of varying temperature and salinity, and enhanced postglacial silicate weathering from the continents can leave multiple isotopic trends plausible during these critical intervals. The positions of these deglaciations appear to correlate specifically to marine oxidation events, with cause/effect relations still under investigation. To capitalize on all of these interpretive possibilities, it is crucial to establish a high-precision and high-resolution strontium chemostratigraphic record over both short and long timescales. However, difficulties in establishing such a record based on carbonates are associated with 1) diagenetic influence over extensive geological time; and 2) petrologic complexities of the studied samples. Using a sequential digestion technique, Liu et al. (2013) demonstrated that these hurdles can be overcome, and that primary 87Sr/86Sr ratios of contemporaneous seawater can be obtained from Marinoan cap dolostones (~635 Ma), which have considerably less Sr than limestones, and whose Sr isotope compositions are commonly ignored in the strontium chemostratigraphic record. This leads to several viable, specific interpretations about the origin of Marinoan cap carbonate: either 1) very fast deposition; 2) slow deposition in a long-Sr-residence-time ocean; 3) mid-cap deposition in a freshwater "Glacial Lake

  9. Interleukin-10 -1082 G/A gene polymorphisms in Egyptian children with CAP

    PubMed Central

    Azab, Seham F.; Abdalhady, Mohamed A.; Elsaadany, Hosam F.; Elkomi, Mohamed A.; Elhindawy, Eman M.; Sarhan, Dina T.; Salam, Mohamed M.A.; Allah, Mayy A.N.; Emam, Ahmed A.; Noah, Maha A.; Abdelsalam, Nasser I.; Abdellatif, Sawsan H.; Rass, Anwar A.; Ismail, Sanaa M.; Gheith, Tarek; Aziz, Khalid A.; Hamed, Mohammed E.; Abdelrahman, Hind M.; Ahmed, Ahmed R.; Nabil, Rehab M.; Abdulmaksoud, Rehab S.; Yousef, Hala Y.

    2016-01-01

    Abstract Community-acquired pneumonia (CAP) is one of the leading causes of death worldwide. Cytokines are involved in the pathogenesis of CAP. To date, only a few studies concerned the association of interleukin-10 (IL-10) gene polymorphisms with CAP. In this study, we aimed to investigate whether the -1082(G/A) polymorphism in the promoter region of the IL-10 gene is involved in susceptibility to and the outcome of CAP, and we also measured the serum level of IL-10 to assess its relation to such polymorphism. This was a case–control study included 100 patients with CAP, and matched with age, gender, and ethnicity of 100 healthy control children. IL-10 -1082(G/A) gene polymorphism was genotyped by polymerase chain reaction-restriction fragment length polymorphism, while the serum IL-10 levels were measured by ELISA method. Compared to the controls subjects, the frequencies of the IL-10 -1082 AA genotype and A allele were observed to be overrepresented in patients with CAP (51%; odds ratio [OR] = 2.8; 95% confidence interval [CI]: 1.5–5.3 for the AA genotype; P < 0.01) and (70%; OR: 1.95; 95% CI: 1.27–3.00 for the A allele; P < 0.01, respectively). We found that patients with the GG genotype had significantly higher serum IL-10 levels (46.7 ± 9.5 pg/mL) compared to those with AG genotype (21.8 ± 4.5 pg/mL) and AA genotype (11.5 ± 3.3 pg/mL); P < 0.01, respectively. Our data revealed a significant positive association between the -1082 GG genotype and susceptibility to severe sepsis, acute respiratory failure, and hospital mortality (OR: 3.8; 95% CI: 1.3–11.2; P < 0.01). We demonstrate for the first time, to the best of our knowledge, that IL-10 -1082 (G/A) gene polymorphism may contribute to susceptibility to CAP in Egyptian children. Moreover, we observed that the presence of a G allele or GG genotype at the -1082 position of the promoter region of the IL-10 gene constitute risk factors for developing severe sepsis

  10. Extending Icelandic volcanological network operations into the ice caps

    NASA Astrophysics Data System (ADS)

    Vogfjord, Kristin; Bean, Chris; Roberts, Matthew; Ofeigsson, Benedikt; Guralp Systems Ltd.

    2013-04-01

    Many of Iceland's most active volcanoes are located under glaciers, with limited access for monitoring equipment. In the warming climate however, a few rock outcrops (nunataks) have emerged from the ice permitting some access improvement, but to properly monitor seismic signals from volcanoes deep inside the ice caps, instruments placed in the ice itself are needed. Continuous, real-time operation of monitoring equipment in harsh climate, heavy snow accumulation and icing conditions on a glacier is a considerable challenge. The FP7 project FUTUREVOLC, which focusses on Icelandic volcanoes, aims for the development of a multiparametric volcano monitoring and early warning system. One of the new developments in the project involves strengthening the existing real-time seismic monitoring and analysis systems by extending the permanent network into the Vatnajökull ice cap. The goal is to improve detection and location of seismic signals, such as microseismicity, LP events, ice-quakes and continuous tremor due to volcanic eruptions at the volcanoes under the ice cap. Real-time processing and discrimination of these signals could give early warnings of an imminent eruption. At subglacial volcanoes however, other processes, such as subglacial floods (jökulhlaup) and subglacial hydrothermal systems - boiling due to sudden drainage -also generate continuous tremor and can therefore lead to false eruption alarms. To minimise the number of false alarms, the network and processing will need to discriminate between the different tremor sources by determining their characteristics and track the temporal evolution and location of the source. For this purpose broad-band instruments will be placed on nunataks as well as in the ice and two short-period arrays will be located at the margin of Vatnajökull, close to subglacial flood paths from the Skaftár ice cauldrons. To record ice movements associated with the jökulhlaups, GPS receivers will be placed on outlet glaciers during

  11. The ATLAS semiconductor tracker end-cap module

    NASA Astrophysics Data System (ADS)

    Abdesselam, A.; Adkin, P. J.; Allport, P. P.; Alonso, J.; Andricek, L.; Anghinolfi, F.; Antonov, A. A.; Apsimon, R. J.; Atkinson, T.; Batchelor, L. E.; Bates, R. L.; Beck, G.; Becker, H.; Bell, P.; Bell, W.; Beneš, P.; Bernabeu, J.; Bethke, S.; Bizzell, J. P.; Blocki, J.; Broklová, Z.; Brož, J.; Bohm, J.; Booker, P.; Bright, G.; Brodbeck, T. J.; Bruckman, P.; Buttar, C. M.; Butterworth, J. M.; Campabadal, F.; Campbell, D.; Carpentieri, C.; Carroll, J. L.; Carter, A. A.; Carter, J. R.; Casse, G. L.; Čermák, P.; Chamizo, M.; Charlton, D. G.; Cheplakov, A.; Chesi, E.; Chilingarov, A.; Chouridou, S.; Chren, D.; Christinet, A.; Chu, M. L.; Cindro, V.; Ciocio, A.; Civera, J. V.; Clark, A.; Colijn, A. P.; Cooke, P. A.; Costa, M. J.; Costanzo, D.; Dabrowski, W.; Danielsen, K. M.; Davies, V. R.; Dawson, I.; de Jong, P.; Dervan, P.; Doherty, F.; Doležal, Z.; Donega, M.; D'Onofrio, M.; Dorholt, O.; Drásal, Z.; Dowell, J. D.; Duerdoth, I. P.; Duxfield, R.; Dwuznik, M.; Easton, J. M.; Eckert, S.; Eklund, L.; Escobar, C.; Fadeyev, V.; Fasching, D.; Feld, L.; Ferguson, D. P. S.; Ferrari, P.; Ferrere, D.; Fleta, C.; Fortin, R.; Foster, J. M.; Fowler, C.; Fox, H.; Freestone, J.; French, R. S.; Fuster, J.; Gadomski, S.; Gallop, B. J.; García, C.; García-Navarro, J. E.; Gibson, S.; Gilchriese, M. G. D.; Gonzalez, F.; Gonzalez-Sevilla, S.; Goodrick, M. J.; Gorisek, A.; Gornicki, E.; Greenall, A.; Greenfield, D.; Gregory, S.; Grigorieva, I. G.; Grillo, A. A.; Grosse-Knetter, J.; Gryska, C.; Guipet, A.; Haber, C.; Hara, K.; Hartjes, F. G.; Hauff, D.; Haywood, S. J.; Hegeman, S. J.; Heinzinger, K.; Hessey, N. P.; Heusch, C.; Hicheur, A.; Hill, J. C.; Hodgkinson, M.; Hodgson, P.; Horažďovský, T.; Hollins, T. I.; Hou, L. S.; Hou, S.; Hughes, G.; Huse, T.; Ibbotson, M.; Iglesias, M.; Ikegami, Y.; Ilyashenko, I.; Issever, C.; Jackson, J. N.; Jakobs, K.; Jared, R. C.; Jarron, P.; Johansson, P.; Jones, R. W. L.; Jones, T. J.; Joos, D.; Joseph, J.; Jovanovic, P.; Jusko, O.; Jusko, V.; Kaplon, J.; Kazi, S.; Ketterer, Ch.; Kholodenko, A. G.; King, B. T.; Kodyš, P.; Koffeman, E.; Kohout, Z.; Kohriki, T.; Kondo, T.; Koperny, S.; Koukol, H.; Král, V.; Kramberger, G.; Kubík, P.; Kudlaty, J.; Lacasta, C.; Lagouri, T.; Lee, S. C.; Leney, K.; Lenz, S.; Lester, C. G.; Liebicher, K.; Limper, M.; Lindsay, S.; Linhart, V.; LLosá, G.; Loebinger, F. K.; Lozano, M.; Ludwig, I.; Ludwig, J.; Lutz, G.; Lys, J.; Maassen, M.; Macina, D.; Macpherson, A.; MacWaters, C.; Magrath, C. A.; Malecki, P.; Mandić, I.; Mangin-Brinet, M.; Martí-García, S.; Matheson, J. P.; Matson, R. M.; McMahon, S. J.; McMahon, T. J.; Meinhardt, J.; Mellado, B.; Melone, J. J.; Mercer, I. J.; Messmer, I.; Mikulec, B.; Mikuž, M.; Miñano, M.; Mitsou, V. A.; Modesto, P.; Moed, S.; Mohn, B.; Moncrieff, S.; Moorhead, G.; Morris, F. S.; Morris, J.; Morrissey, M.; Moser, H. G.; Moszczynski, A.; Muijs, A. J. M.; Murray, W. J.; Muskett, D.; Nacher, J.; Nagai, K.; Nakano, I.; Nickerson, R. B.; Nisius, R.; Oye, O. K.; O'Shea, V.; Paganis, E.; Parker, M. A.; Parzefall, U.; Pater, J. R.; Peeters, S. J. M.; Pellegrini, G.; Pelleriti, G.; Pernegger, H.; Perrin, E.; Phillips, P. W.; Pilavova, L. V.; Poltorak, K.; Pospíšil, S.; Postranecky, M.; Pritchard, T.; Prokofiev, K.; Rafí, J. M.; Raine, C.; Ratoff, P. N.; Řezníček, P.; Riadovikov, V. N.; Richter, R. H.; Robichaud-Véronneau, A.; Robinson, D.; Rodriguez-Oliete, R.; Roe, S.; Rudge, A.; Runge, K.; Saavedra, A.; Sadrozinski, H. F. W.; Sanchez, F. J.; Sandaker, H.; Saxon, D. H.; Scheirich, D.; Schieck, J.; Seiden, A.; Sfyrla, A.; Slavíček, T.; Smith, K. M.; Smith, N. A.; Snow, S. W.; Solar, M.; Sopko, B.; Sopko, V.; Sospedra, L.; Spencer, E.; Stanecka, E.; Stapnes, S.; Stastny, J.; Strachko, V.; Stradling, A.; Stugu, B.; Su, D. S.; Sutcliffe, P.; Szczygiel, R.; Tanaka, R.; Taylor, G.; Teng, P. K.; Terada, S.; Thompson, R. J.; Titov, M.; Toczek, B.; Tovey, D. R.; Tratzl, G.; Troitsky, V. L.; Tseng, J.; Turala, M.; Turner, P. R.; Tyndel, M.; Ullán, M.; Unno, Y.; Vickey, T.; Van der Kraaij, E.; Viehhauser, G.; Villani, E. G.; Vitek, T.; Vu Anh, T.; Vorobiev, A. P.; Vossebeld, J. H.; Wachler, M.; Wallny, R.; Ward, C. P.; Warren, M. R. M.; Webel, M.; Weber, M.; Weber, M.; Weidberg, A. R.; Weilhammer, P.; Wells, P. S.; Wetzel, P.; Whitley, M.; Wiesmann, M.; Wilhelm, I.; Willenbrock, M.; Wilmut, I.; Wilson, J. A.; Winton, J.; Wolter, M.; Wormald, M. P.; Wu, S. L.; Wu, X.; Zhu, H.; Bingefors, N.; Brenner, R.; Ekelof, T.

    2007-06-01

    The challenges for the tracking detector systems at the LHC are unprecedented in terms of the number of channels, the required read-out speed and the expected radiation levels. The ATLAS Semiconductor Tracker (SCT) end-caps have a total of about 3 million electronics channels each reading out every 25 ns into its own on-chip 3.3 μs buffer. The highest anticipated dose after 10 years operation is 1.4×1014 cm-2 in units of 1 MeV neutron equivalent (assuming the damage factors scale with the non-ionising energy loss). The forward tracker has 1976 double-sided modules, mostly of area ˜70 cm2, each having 2×768 strips read out by six ASICs per side. The requirement to achieve an average perpendicular radiation length of 1.5% X0, while coping with up to 7 W dissipation per module (after irradiation), leads to stringent constraints on the thermal design. The additional requirement of 1500e- equivalent noise charge (ENC) rising to only 1800e- ENC after irradiation, provides stringent design constraints on both the high-density Cu/Polyimide flex read-out circuit and the ABCD3TA read-out ASICs. Finally, the accuracy of module assembly must not compromise the 16 μm (rφ) resolution perpendicular to the strip directions or 580 μm radial resolution coming from the 40 mrad front-back stereo angle. A total of 2210 modules were built to the tight tolerances and specifications required for the SCT. This was 234 more than the 1976 required and represents a yield of 93%. The component flow was at times tight, but the module production rate of 40-50 per week was maintained despite this. The distributed production was not found to be a major logistical problem and it allowed additional flexibility to take advantage of where the effort was available, including any spare capacity, for building the end-cap modules. The collaboration that produced the ATLAS SCT end-cap modules kept in close contact at all times so that the effects of shortages or stoppages at different sites could be

  12. Mercury's Core

    NASA Astrophysics Data System (ADS)

    Peale, S. J.

    2005-05-01

    In determining Mercury's core structure from its rotational properties, the location of Cassini state 1 is crucial. Convincing radar evidence indicates that the mantle rests on a liquid layer (Margot et al. 2005), but there are no empirical constraints on the moment of inertia C/MR2, which constraints must wait for the determination of the gravitational coefficients J2 and C22 from the MESSENGER orbiting spacecraft, and an accurate determination of the obliquity of the Cassini state. Tidal and core-mantle dissipation drive the spin to the Cassini state with a time scale O(105) years, so the spin should occupy the Cassini state and thereby define its obliquity---unless there has been a recent excitation of a free precession of the spin. Another way the spin might be displaced from the Cassini state is if the variations in the orbital elements, which change the position of the Cassini state, cause the spin axis to lag behind as it attempts to follow the state. Fortunately, the solid angle the spin axis encloses as it precesses around the Cassini state is an adiabatic invariant, and it is conserved if the orbital element variations are slow compared to the precession rate. As the precession period is O(1000) years, and the time scales of orbital parameter variations are O(105) years, the spin axis should remain very close to the Cassini state if it were ever close. But how close is close? The increasing precision of the radar and eventual spacecraft measurements warrants a check on the likely proximity of the spin axis to the Cassini state. By numerically following the positions of the spin axis and Cassini state with orbital parameters varying with time scales and amplitudes comparable to the real variations, we show that the spin should remain within 1″ of the Cassini state once dissipative torques bring it there. The current spin axis position should thus define the Cassini state sufficiently to put reasonably tight constraints on the core structure

  13. CAPS1 stabilizes the state of readily releasable synaptic vesicles to fusion competence at CA3–CA1 synapses in adult hippocampus

    PubMed Central

    Shinoda, Yo; Ishii, Chiaki; Fukazawa, Yugo; Sadakata, Tetsushi; Ishii, Yuki; Sano, Yoshitake; Iwasato, Takuji; Itohara, Shigeyoshi; Furuichi, Teiichi

    2016-01-01

    Calcium-dependent activator protein for secretion 1 (CAPS1) regulates exocytosis of dense-core vesicles in neuroendocrine cells and of synaptic vesicles in neurons. However, the synaptic function of CAPS1 in the mature brain is unclear because Caps1 knockout (KO) results in neonatal death. Here, using forebrain-specific Caps1 conditional KO (cKO) mice, we demonstrate, for the first time, a critical role of CAPS1 in adult synapses. The amplitude of synaptic transmission at CA3–CA1 synapses was strongly reduced, and paired-pulse facilitation was significantly increased, in acute hippocampal slices from cKO mice compared with control mice, suggesting a perturbation in presynaptic function. Morphological analysis revealed an accumulation of synaptic vesicles in the presynapse without any overall morphological change. Interestingly, however, the percentage of docked vesicles was markedly decreased in the Caps1 cKO. Taken together, our findings suggest that CAPS1 stabilizes the state of readily releasable synaptic vesicles, thereby enhancing neurotransmitter release at hippocampal synapses. PMID:27545744

  14. Critical CRBR core pressure

    SciTech Connect

    Ju, F.D.

    1980-06-01

    The conditions are detailed under which gas pressure will cause or initiate failure in the structural containment of the fuel core. The Clinch River Breeder Reactor Plant is the prototype structure. Two general classes of problems have been studied, representing two entirely distinct configurations of containment failure. The first model determines the minimum pressure to lift a portion or the entire core from its containment. The second model estimates the critical pressure above which the fuel rods interior to the hexagonal fuel can warp, leading to blockage of the gas passages. Such blockage might cause further buildup of the gas pressure to a level causing the failure of the fuel rod containment in the hexagonal fuel container.

  15. Stratigraphic features of firn as proxy climate signals at the summit ice cap of Ushkovsky volcano, Kamchatka, Russia

    SciTech Connect

    Shiraiwa, Takayuki; Yamaguchi, Satoru; Muravyev, Y.D.

    1997-11-01

    Field observations were conducted at the summit ice cap of the Ushkovsky volcano, central Kamchatka, in the summer of 1996, in order to evaluate the potential of the ice cap for reconstruction of the past climate over Kamchatka. A 27-m-long firn-core contains an approximate 27-yr record of net balance with an average accumulation rate of 0.57 m a{sup -1} water equivalent. The temperature of the firn is -16.5{degrees}C at 10-m depth. Average annual accumulation rates are calculated by reference to dated ash layers and amount to between 0.38 and 0.88 m a{sup -1} during six fixed periods. Depth and age of pore close-off are calculated as 58 m and 66 yr at this site by empirical formulas. Comparisons of the accumulation rates with winter precipitation at lowland stations indicate that there is a positive relationship with winter precipitation on the eastern and western coasts of the peninsula. We cannot find a clear relation between the rates and annual average sea-ice extent in the Sea of Okhotsk, which implies the vapor source to the ice cap could have been the North Pacific. Melt feature percentage in the firn core displays a clear positive relationship with summer air temperature at 700 hPa over Kamchatka. The result obtained suggests that the ice cap has potential for the reconstruction of paleoclimate over the Kamchatka Peninsula. 15 refs., 9 figs.

  16. Toward the mechanism of eIF4F-mediated ribosomal attachment to mammalian capped mRNAs.

    PubMed

    Kumar, Parimal; Hellen, Christopher U T; Pestova, Tatyana V

    2016-07-01

    Ribosomal attachment to mammalian capped mRNAs is achieved through the cap-eukaryotic initiation factor 4E (eIF4E)-eIF4G-eIF3-40S chain of interactions, but the mechanism by which mRNA enters the mRNA-binding channel of the 40S subunit remains unknown. To investigate this process, we recapitulated initiation on capped mRNAs in vitro using a reconstituted translation system. Formation of initiation complexes at 5'-terminal AUGs was stimulated by the eIF4E-cap interaction and followed "the first AUG" rule, indicating that it did not occur by backward scanning. Initiation complexes formed even at the very 5' end of mRNA, implying that Met-tRNAi (Met) inspects mRNA from the first nucleotide and that initiation does not have a "blind spot." In assembled initiation complexes, the cap was no longer associated with eIF4E. Omission of eIF4A or disruption of eIF4E-eIF4G-eIF3 interactions converted eIF4E into a specific inhibitor of initiation on capped mRNAs. Taken together, these results are consistent with the model in which eIF4E-eIF4G-eIF3-40S interactions place eIF4E at the leading edge of the 40S subunit, and mRNA is threaded into the mRNA-binding channel such that Met-tRNAi (Met) can inspect it from the first nucleotide. Before entering, eIF4E likely dissociates from the cap to overcome steric hindrance. We also found that the m(7)G cap specifically interacts with eIF3l. PMID:27401559

  17. Core-shell nano-architectures: the incorporation mechanism of hydrophobic nanoparticles into the aqueous core of a microemulsion.

    PubMed

    Scorciapino, Mariano A; Sanna, Roberta; Ardu, Andrea; Orrù, Federica; Casu, Mariano; Musinu, Anna; Cannas, Carla

    2013-10-01

    This work presents an in-depth investigation of the molecular interactions in the incorporation mechanism of colloidal hydrophobic-capped nanoparticles into the hydrophilic core of reverse microemulsions. (1)H Nuclear Magnetic Resonance (NMR) was employed to obtain molecular level details of the interaction between the nanoparticles capping amphiphiles and the microemulsion surfactants. The model system of choice involved oleic acid (OAC) and oleylamine (OAM) as capping molecules, while igepal-CO520 was the surfactant. The former were studied both in their "free" state and "ligated" one, i.e., bound to nanoparticles. The latter was investigated either in cyclohexane (micellar solution) or in water/cyclohexane microemulsions. The approach was extremely useful to gain a deeper understanding of the equilibria involved in this complex system (oleic acid capped-Bi2S3 in igepal/water/cyclohexane microemulsions). In difference to previously proposed mechanisms, the experimental data showed that the high affinity of the capping ligands for the reverse micelle interior was the drivingforce for the incorporation of the nanoparticles. A simple ligand-exchange mechanism could be ruled out. The collected information about the nanoparticle incorporation mechanism is extremely useful to develop new synthetic routes with an improved/tuned coating efficiency, in order to tailor the core-shell structure preparation. PMID:23910706

  18. Incorporating Wind Generation in Cap and Trade Programs

    SciTech Connect

    Bluestein, J.; Salerno, E.; Bird, L.; Vimmerstedt, L.

    2006-07-01

    Cap and trade programs are increasingly being used to reduce emissions from electricity generation in the United States. Cap and trade programs primarily target emitting generators, but programs have also included renewable generators, such as wind generators. States cite several reasons why they have considered the policy option of including renewable generators in cap and trade programs: to provide an incentive for lower-emitting generation, to achieve emissions reductions in non-capped pollutants, and to gain local economic benefits associated with renewable energy projects. The U.S. Environmental Protection Agency also notes these rationales for considering this policy alternative, and the National Association of Regulatory Commissioners (NARUC) passed a resolution supporting the inclusion of renewable energy in cap and trade programs. This report explores why states consider this policy option, what participation could mean for wind generators, and how wind generation can most effectively be included in state, federal, and regional cap and trade programs.

  19. Magnetically capped rolled-up nanomembranes.

    PubMed

    Streubel, Robert; Thurmer, Dominic J; Makarov, Denys; Kronast, Florian; Kosub, Tobias; Kravchuk, Volodymyr; Sheka, Denis D; Gaididei, Yuri; Schäfer, Rudolf; Schmidt, Oliver G

    2012-08-01

    Modifying the curvature in magnetic nanostructures is a novel and elegant way toward tailoring physical phenomena at the nanoscale, allowing one to overcome limitations apparent in planar counterparts. Here, we address curvature-driven changes of static magnetic properties in cylindrically curved magnetic segments with different radii of curvature. The curved architectures are prepared by capping nonmagnetic micrometer- and nanometer-sized rolled-up membranes with a soft-magnetic 20 nm thick permalloy (Ni(80)Fe(20)) film. A quantitative comparison between the magnetization reversal processes in caps with different diameters is given. The phase diagrams of magnetic equilibrium domain patterns (diameter versus length) are generated. For this, joint experimental, including X-ray magnetic circular dichroism photoelectron emission microscopy (XMCD-PEEM), and theoretical studies are carried out. The anisotropic magnetostatic interaction in cylindrically curved architectures originating from the thickness gradient reduces substantially the magnetostatic interaction between closely packed curved nanowires. This feature is beneficial for racetrack memory devices, since a much higher areal density might be achieved than possible with planar counterparts.

  20. Comparison of Polar Cap (PC) index calculations.

    NASA Astrophysics Data System (ADS)

    Stauning, P.

    2012-04-01

    The Polar Cap (PC) index introduced by Troshichev and Andrezen (1985) is derived from polar magnetic variations and is mainly a measure of the intensity of the transpolar ionospheric currents. These currents relate to the polar cap antisunward ionospheric plasma convection driven by the dawn-dusk electric field, which in turn is generated by the interaction of the solar wind with the Earth's magnetosphere. Coefficients to calculate PCN and PCS index values from polar magnetic variations recorded at Thule and Vostok, respectively, have been derived by several different procedures in the past. The first published set of coefficients for Thule was derived by Vennerstrøm, 1991 and is still in use for calculations of PCN index values by DTU Space. Errors in the program used to calculate index values were corrected in 1999 and again in 2001. In 2005 DMI adopted a unified procedure proposed by Troshichev for calculations of the PCN index. Thus there exists 4 different series of PCN index values. Similarly, at AARI three different sets of coefficients have been used to calculate PCS indices in the past. The presentation discusses the principal differences between the various PC index procedures and provides comparisons between index values derived from the same magnetic data sets using the different procedures. Examples from published papers are examined to illustrate the differences.

  1. MFTF-. cap alpha. + T progress report

    SciTech Connect

    Nelson, W.D.

    1985-04-01

    Early in FY 1983, several upgrades of the Mirror Fusion Test Facility (MFTF-B) at Lawrence Livermore National Laboratory (LLNL) were proposed to the fusion community. The one most favorably received was designated MFTF-..cap alpha..+T. The engineering design of this device, guided by LLNL, has been a principal activity of the Fusion Engineering Design Center during FY 1983. This interim progress report represents a snapshot of the device design, which was begun in FY 1983 and will continue for several years. The report is organized as a complete design description. Because it is an interim report, some parts are incomplete; they will be supplied as the design study proceeds. As described in this report, MFTF-..cap alpha..+T uses existing facilities, many MFTF-B components, and a number of innovations to improve on the physics parameters of MFTF-B. It burns deuterium-tritium and has a central-cell Q of 2, a wall loading GAMMA/sub n/ of 2 MW/m/sup 2/ (with a central-cell insert module), and an availability of 10%. The machine is fully shielded, allows hands-on maintenance of components outside the vacuum vessel 24 h after shutdown, and has provisions for repair of all operating components.

  2. Cannibalism and early capping: strategy of honeybee colonies in times of experimental pollen shortages.

    PubMed

    Schmickl, T; Crailsheim, K

    2001-09-01

    We observed the impact of bad pollen supply (non-foraging due to artificial rain and pollen removal under poor-foraging conditions) on the survival of honey bee larvae, and on the total development time from egg-laying to the capping of a larval cell. Five days of non-foraging led to cannibalism of larvae younger than 3 days old and to a shortening of the time until larvae were sealed, but 4- and 5-day-old larvae survived even worse pollen supply situations. Manual pollen removal and reduction of income (pollen trap) induced cannibalism of younger larvae. The larvae's mean capping age significantly correlated with the mean pollen income: the less pollen was stored by the hive during the larvae's development, the earlier the larvae were capped. Both behavioral patterns lead to a quick reduction in the amount of unsealed older brood in response to a shortage of available protein. Older larvae have the highest pollen demand, so this strategy compensates for a shortage of supply by reducing demand. Additionally worker jelly gets enriched by protein gained from cannibalism, and the early capping of older larvae saves the oldest part of the brood, which represents the highest broodcare investment. PMID:11730301

  3. pH responsive polyurethane (core) and cellulose acetate phthalate (shell) electrospun fibers for intravaginal drug delivery.

    PubMed

    Hua, Dawei; Liu, Zhongche; Wang, Fang; Gao, Buhong; Chen, Fei; Zhang, Qilu; Xiong, Ranhua; Han, Jingquan; Samal, Sangram Keshari; De Smedt, Stefaan C; Huang, Chaobo

    2016-10-20

    In this study we present the use of co-axial electrospinning to produce core-shell composite micro-/nano- fibers of polyurethane (PU) and cellulose acetate phthalate (CAP). The designed fibers possess enhanced mechanical properties with a tensile strength of 13.27±2.32MPa, which is a clear improvement over the existing CAP fibers that suffer from a poor mechanical strength (0.2±0.03MPa). The CAP imparts pH responsiveness to the core-shell structure giving the fibers potential for "semen sensitive" (intravaginal) drug delivery. PMID:27474676

  4. pH responsive polyurethane (core) and cellulose acetate phthalate (shell) electrospun fibers for intravaginal drug delivery.

    PubMed

    Hua, Dawei; Liu, Zhongche; Wang, Fang; Gao, Buhong; Chen, Fei; Zhang, Qilu; Xiong, Ranhua; Han, Jingquan; Samal, Sangram Keshari; De Smedt, Stefaan C; Huang, Chaobo

    2016-10-20

    In this study we present the use of co-axial electrospinning to produce core-shell composite micro-/nano- fibers of polyurethane (PU) and cellulose acetate phthalate (CAP). The designed fibers possess enhanced mechanical properties with a tensile strength of 13.27±2.32MPa, which is a clear improvement over the existing CAP fibers that suffer from a poor mechanical strength (0.2±0.03MPa). The CAP imparts pH responsiveness to the core-shell structure giving the fibers potential for "semen sensitive" (intravaginal) drug delivery.

  5. Acoustic Monitoring of the Arctic Ice Cap

    NASA Astrophysics Data System (ADS)

    Porter, D. L.; Goemmer, S. A.; Chayes, D. N.

    2012-12-01

    Introduction The monitoring of the Arctic Ice Cap is important economically, tactically, and strategically. In the scenario of ice cap retreat, new paths of commerce open, e.g. waterways from Northern Europe to the Far East. Where ship-going commerce is conducted, the U.S. Navy and U.S. Coast Guard have always stood guard and been prepared to assist from acts of nature and of man. It is imperative that in addition to measuring the ice from satellites, e.g. Icesat, that we have an ability to measure the ice extent, its thickness, and roughness. These parameters play an important part in the modeling of the ice and the processes that control its growth or shrinking and its thickness. The proposed system consists of three subsystems. The first subsystem is an acoustic source, the second is an array of geophones and the third is a system to supply energy and transmit the results back to the analysis laboratory. The subsystems are described below. We conclude with a plan on how to tackle this project and the payoff to the ice cap modeler and hence the users, i.e. commerce and defense. System Two historically tested methods to generate a large amplitude multi-frequency sound source include explosives and air guns. A new method developed and tested by the University of Texas, ARL is a combustive Sound Source [Wilson, et al., 1995]. The combustive sound source is a submerged combustion chamber that is filled with the byproducts of the electrolysis of sea water, i.e. Hydrogen and Oxygen, an explosive mixture which is ignited via a spark. Thus, no additional compressors, gases, or explosives need to be transported to the Arctic to generate an acoustic pulse capable of the sediment and the ice. The second subsystem would be geophones capable of listening in the O(10 Hz) range and transmitting that data back to the laboratory. Thus two single arrays of geophones arranged orthogonal to each other with a range of 1000's of kilometers and a combustive sound source where the two

  6. Microfine toe caps: an innovative and cost-saving solution.

    PubMed

    Elwell, Rebecca; Wigg, Jane

    2015-04-01

    This article discusses the use of Microfine toe caps (Haddenham, UK) for the treatment of digit swelling. It will discuss the indications and contraindications of the device and offers some case studies where toe caps have been used in clinical practice. The use of the Microfine toe cap offers an alternative to toe bandaging, has many different applications and can be safe and time-saving to apply when used appropriately following a full and holistic assessment.

  7. Capped bit patterned media for high density magnetic recording

    NASA Astrophysics Data System (ADS)

    Li, Shaojing; Livshitz, Boris; Bertram, H. Neal; Inomata, Akihiro; Fullerton, Eric E.; Lomakin, Vitaliy

    2009-04-01

    A capped composite patterned medium design is described which comprises an array of hard elements exchange coupled to a continuous cap layer. The role of the cap layer is to lower the write field of the individual hard element and introduce ferromagnetic exchange interactions between hard elements to compensate the magnetostatic interactions. Modeling results show significant reduction in the reversal field distributions caused by the magnetization states in the array which is important to prevent bit errors and increase achievable recording densities.

  8. Preform spar cap for a wind turbine rotor blade

    DOEpatents

    Livingston, Jamie T.; Driver, Howard D.; van Breugel, Sjef; Jenkins, Thomas B.; Bakhuis, Jan Willem; Billen, Andrew J.; Riahi, Amir

    2011-07-12

    A spar cap for a wind turbine rotor blade. The spar cap may include multiple preform components. The multiple preform components may be planar sheets having a swept shape with a first end and a second end. The multiple preform components may be joined by mating the first end of a first preform component to the second end of a next preform component, forming the spar cap.

  9. Quelccaya Ice Core Evidence of Widespread Atmospheric Pollution from Colonial Metallurgy after the Spanish Conquest of South America (1532 AD)

    NASA Astrophysics Data System (ADS)

    Gabrielli, P.; Uglietti, C.; Cooke, C. A.; Thompson, L. G.

    2014-12-01

    A few ice core records recovered from remote arctic regions suggest a widespread impact of toxic trace elements (Pb, Cu, Sb, As and Bi) to the North Hemisphere atmosphere prior to the onset of the Industrial Revolution (1780s-1830s). In the Southern Hemisphere, evidence for preindustrial trace element emissions are, to date, limited to sediment cores recovered from lakes located within the immediate airshed of major metallurgical centers of South America. Thus it remains unresolved whether they could have had a larger scale impact. Here, we present an annually resolved ice core record of anthropogenic trace element deposition from the remote drilling site of the Quelccaya Ice Cap (Peru) that spans 793-1989 AD. During the pre-Inca period (i.e., prior to ~1450 AD) the deposition of trace elements was dominated by the fallout of aeolian dust from the deglaciated margins of the ice cap and of ash from occasional volcanic eruptions. In contrast, the ice core record indicates a clear anthropogenic signal emerging after the onset of large scale colonial mining and metallurgy (1532-1820 AD), ~300 years prior to the Industrial Revolution during the last part of the Little Ice Age. This shift was coincidental with a major technological transition for silver extraction (1572 AD), from lead-based smelting to mercury amalgamation, that initiated a major increase in ore mining and milling that likely resulted in an increase of metallic dust emissions. While atmospheric trace element deposition resulting from colonial metallurgy was certainly much larger than during the pre-Colonial period, trace element fallout during the Colonial era was still several factors lower than during the 20th century, when the construction of the trans-Andean railway and highways promoted a widespread societal and industrial development of South America.

  10. The little ice age as recorded in the stratigraphy of the tropical quelccaya ice cap.

    PubMed

    Thompson, L G; Mosley-Thompson, E; Dansgaard, W; Grootes, P M

    1986-10-17

    The analyses of two ice cores from a southern tropical ice cap provide a record of climatic conditions over 1000 years for a region where other proxy records are nearly absent. Annual variations in visible dust layers, oxygen isotopes, microparticle concentrations, conductivity, and identification of the historical (A.D. 1600) Huaynaputina ash permit accurate dating and time-scale verification. The fact that the Little Ice Age (about A.D. 1500 to 1900) stands out as a significant climatic event in the oxygen isotope and electrical conductivity records confirms the worldwide character of this event.

  11. Anisotropic. cap alpha. -emission of on-line separated isotopes

    SciTech Connect

    Wouters, J.; Vandeplassche, D.; van Walle, E.; Severijns, N.; Van Haverbeke, J.; Vanneste, L.

    1987-12-10

    The technical realization of particle detection at very low temperatures (4K) has made it possible to study for the first time the anisotropic ..cap alpha..-decay of oriented nuclei which have been produced, separated and implanted on line. The measured ..cap alpha..-angular distributions reveal surprising new results on nuclear aspects as well as in solid state physics. The nuclear structure information from these data questions the older ..cap alpha..-decay theoretical interpretation and urges for a reaxamination of the earliest work on anisotropic ..cap alpha..-decay.

  12. Trap door and underside of cap stone of pyramid ion ...

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

    Trap door and underside of cap stone of pyramid ion - Washington Monument, High ground West of Fifteenth Street, Northwest, between Independence & Constitution Avenues, Washington, District of Columbia, DC

  13. Design and Performance of Capping Layers for EUV Multilayer Mirrors

    SciTech Connect

    Bajt, S; Chapman, H N; Nuygen, N; Alameda, J; Robinson, J C; Malinowski, M; Gullikson, E; Aquila, A; Tarrio, C; Grantham, S

    2003-03-10

    The reflectance stability of multilayer coatings for extreme ultraviolet lithography (EUVL) in a commercial tool environment is of uttermost importance to ensure continuous exposures with minimum maintenance cost. We have made substantial progress in designing the protective capping layer coatings, understanding their performance and estimating their lifetimes based on accelerated electron beam and EUV exposure studies. Our current capping layer coatings have about 40 times longer lifetimes than Si-capped multilayer optics. Nevertheless, the lifetime of current Ru-capped multilayers is too short to satisfy commercial tool requirements and further improvements are essential.

  14. Adsorption properties of. cap alpha. -modification of boron nitride

    SciTech Connect

    Gavrilova, T.B.; Kiselev, A.V.; Parshina, I.V.; Roshchina, T.M.

    1986-11-01

    The adsorption properties of four samples of ..cap alpha..-BN were studied by means of gas chromatography. The particles of ..cap alpha..-BN particles, according to data obtained by electron microscopy, have the shape of thin platelets. A sample of ..cap alpha..-BN prepared from magnesium polyboride was found to be the most nearly homogeneous adsorbent. For a number of n-alkanes, benzene, and alkylbenzenes, data have been obtained on the retention volumes (Henry constants) and the differential heats of adsorption for surface coverages approaching zero. These thermodynamic data on the adsorption showed that ..cap alpha..-BN, like graphitized thermal carbon black, is a nonspecific adsorbent.

  15. Generalized method for constructing the atomic coordinates of nanotube caps

    NASA Astrophysics Data System (ADS)

    Robinson, M.; Suarez-Martinez, I.; Marks, N. A.

    2013-04-01

    A practical numerical method for the rapid construction of nanotube caps is proposed. Founded upon the notion of lattice duality, the algorithm considers the face dual representation of a given nanotube which is used to solve an energy minimization problem analogous to The Thomson Problem. Not only does this produce caps for nanotubes of arbitrary chirality, but the caps generated will be physically sensible and in most cases the lowest energy structure. To demonstrate the applicability of the technique, caps of the (5,5) and the (10,0) nanotubes are investigated by means of density-functional tight binding (DFTB). The calculation of cap energies highlights the ability of the algorithm to produce lowest energy caps. Due to the preferential construction of spherical caps, the technique is particularly well suited for the construction of capped multiwall nanotubes (MWNTs). To validate this proposal and the overall robustness of the algorithm, a MWNT is constructed containing the chiralities (9,2)@(15,6)@(16,16). The algorithm presented paves the way for future computational investigations into the physics and chemistry of capped nanotubes.

  16. COLORFUL FIREWORKS FINALE CAPS A STAR'S LIFE

    NASA Technical Reports Server (NTRS)

    2002-01-01

    stars begin a complex chain of events that lead to the final dramatic explosion. Their cores rapidly collapse, releasing an enormous amount of gravitational energy. This sudden burst of energy reverses the collapse and tosses most of the star's mass into space. The ejected material can travel as fast as 45 million miles per hour (72 million kilometers per hour). The images were taken with the Wide Field and Planetary Camera 2 in January 2000 and January 2002. Image Credit: NASA and the Hubble Heritage Team (STScI/AURA) Acknowledgment: R. Fesen (Dartmouth) and J. Morse (Univ. of Colorado)

  17. First continuous flow analysis results from the Greenland ReCAP project

    NASA Astrophysics Data System (ADS)

    Kjær, Helle Astrid

    2016-04-01

    The new Renland ice core was drilled in summer 2015 in Greenland and measured by means of Continuous flow analysis during the last 3 months of 2015. The Renland ice core was obtained as part of the ReCAP project, extending 584.11 meters to the bottom of the Renland ice cap located in east Greenland. The unique position on a mountain saddle above 2000 meters altitude, but close to the coast, ensures that the Renland ice core offers high accumulation, but also reaches far back in time. Preliminary results show that the record holds ice from the past warm interglacial period, the Eemian. The record was analyzed for multiple elements including the forest fire tracers NH4+ and black carbon, insoluble dust particles by means of Abakus laser particle counter and the dust ion Ca2+, sea salt Na and acidity useful for finding volcanic layers to date the core. Further H2O2, and the nutrients Fe and dissolved reactive phosphorus was analyzed as well as the temperature indicator δ18O all by means of continuous flow analysis (CFA). The core was melted at a rate of 3 cm/min providing a temporal resolution for most components determined sufficient to resolve annual layers through the Holocene. The glacial section is strongly thinned, but nonetheless due to the high resolution of the measurements all DO events could be identified. Below the glacial section another ˜20 meters of warm Eemian ice have been analysed. Here we present the first chemistry results as obtained by continuous flow analysis (CFA).

  18. Ice Core Records of Recent Northwest Greenland Climate

    NASA Astrophysics Data System (ADS)

    Osterberg, E. C.; Wong, G. J.; Ferris, D.; Lutz, E.; Howley, J. A.; Kelly, M. A.; Axford, Y.; Hawley, R. L.

    2014-12-01

    Meteorological station data from NW Greenland indicate a 3oC temperature rise since 1990, with most of the warming occurring in fall and winter. According to remote sensing data, the NW Greenland ice sheet (GIS) and coastal ice caps are responding with ice mass loss and margin retreat, but the cryosphere's response to previous climate variability is poorly constrained in this region. We are developing multi-proxy records (lake sediment cores, ice cores, glacial geologic data, glaciological models) of Holocene climate change and cryospheric response in NW Greenland to improve projections of future ice loss and sea level rise in a warming climate. As part of our efforts to develop a millennial-length ice core paleoclimate record from the Thule region, we collected and analyzed snow pit samples and short firn cores (up to 21 m) from the coastal region of the GIS (2Barrel site; 76.9317o N, 63.1467o W, 1685 m el.) and the summit of North Ice Cap (76.938o N, 67.671o W, 1273 m el.) in 2011, 2012 and 2014. The 2Barrel ice core record has statistically significant relationships with regional spring and fall Baffin Bay sea ice extent, summertime temperature, and annual precipitation. Here we evaluate relationships between the 2014 North Ice Cap firn core glaciochemical record and climate variability from regional instrumental stations and reanalysis datasets. We compare the coastal North Ice Cap record to more inland records from 2Barrel, Camp Century and NEEM to evaluate spatial and elevational gradients in recent NW Greenland climate change.

  19. Complications of Cardiac Perforation and Lead Dislodgement with an MRI-Conditional Pacing Lead: a Korean Multi-Center Experience

    PubMed Central

    2016-01-01

    Medtronic CapSureFix MRI 5086 pacing lead (5086; Medtronic, Inc., Minneapolis, MN, USA) has been reported to be associated with increased cardiac perforation and lead dislodgement. This study aimed to compare the incidence of cardiac perforation and lead dislodgement within 30 days after pacemaker implantation between 5086 MRI lead and previous Medtronic CapSureFix Novus 5076 non-MRI pacing lead. This was a nationwide, multicenter retrospective study in which we compared the incidence of adverse events between 277 patients implanted with 5086 lead and 205 patients implanted with 5076 lead between March 2009 and September 2014. Cardiac perforation within 30 days of pacemaker implantation occurred in 4 patients (1.4%) with the 5086 lead and in no patient with the 5076 lead (P = 0.084). Lead dislodgement occurred in 8 patients (2.9%) with the 5086 lead and in 5 patients (2.4%) with the 5076 lead (P = 0.764). On multivariate logistic regression analysis, age was significantly associated with cardiac perforation. Congestive heart failure and implantation of right atrial (RA) lead at RA free wall or septum were significant factors for the incidence of lead dislodgement and lead revision. The incidence of cardiac perforation and lead dislodgement were not statistically different between the patients with 5086 lead and the patients with 5076 lead. However, careful attention for cardiac perforation may be needed when using the 5086 MRI lead, especially in elderly patients. PMID:27510382

  20. Complications of Cardiac Perforation and Lead Dislodgement with an MRI-Conditional Pacing Lead: a Korean Multi-Center Experience.

    PubMed

    Kwon, Chang Hee; Choi, Jin Hee; Kim, Jun; Jo, Uk; Lee, Ji Hyun; Lee, Woo Seok; Kim, Yoo Ri; Lee, Soo Yong; Whang, Ki Won; Yang, Jihyun; Kim, Sung Hwan; Oh, Yong Seog; Park, Kyoung Min; Nam, Gi Byoung; Choi, Kee Joon; Kim, You Ho

    2016-09-01

    Medtronic CapSureFix MRI 5086 pacing lead (5086; Medtronic, Inc., Minneapolis, MN, USA) has been reported to be associated with increased cardiac perforation and lead dislodgement. This study aimed to compare the incidence of cardiac perforation and lead dislodgement within 30 days after pacemaker implantation between 5086 MRI lead and previous Medtronic CapSureFix Novus 5076 non-MRI pacing lead. This was a nationwide, multicenter retrospective study in which we compared the incidence of adverse events between 277 patients implanted with 5086 lead and 205 patients implanted with 5076 lead between March 2009 and September 2014. Cardiac perforation within 30 days of pacemaker implantation occurred in 4 patients (1.4%) with the 5086 lead and in no patient with the 5076 lead (P = 0.084). Lead dislodgement occurred in 8 patients (2.9%) with the 5086 lead and in 5 patients (2.4%) with the 5076 lead (P = 0.764). On multivariate logistic regression analysis, age was significantly associated with cardiac perforation. Congestive heart failure and implantation of right atrial (RA) lead at RA free wall or septum were significant factors for the incidence of lead dislodgement and lead revision. The incidence of cardiac perforation and lead dislodgement were not statistically different between the patients with 5086 lead and the patients with 5076 lead. However, careful attention for cardiac perforation may be needed when using the 5086 MRI lead, especially in elderly patients. PMID:27510382

  1. Is There an Effect of Incremental Welfare Benefits on Fertility Behavior?: A Look at the Family Cap

    ERIC Educational Resources Information Center

    Kearney, Melissa Schettini

    2004-01-01

    This analysis exploits the variation across states in the timing of policy implementation to determine if family cap policies lead to a reduction in births to women aged 15 to 34. Vital statistics birth data for the years 1989 to 1998 offer no such evidence. The data reject a decline in births of more than one percent. The finding is robust to…

  2. Speciation of a group I intron into a lariat capping ribozyme

    PubMed Central

    Meyer, Mélanie; Nielsen, Henrik; Oliéric, Vincent; Roblin, Pierre; Johansen, Steinar D.; Westhof, Eric; Masquida, Benoît

    2014-01-01

    The lariat-capping (LC) ribozyme is a natural ribozyme isolated from eukaryotic microorganisms. Despite apparent structural similarity to group I introns, the LC ribozyme catalyzes cleavage by a 2′,5′ branching reaction, leaving the 3′ product with a 3-nt lariat cap that functionally substitutes for a conventional mRNA cap in the downstream pre-mRNA encoding a homing endonuclease. We describe the crystal structures of the precleavage and postcleavage LC ribozymes, which suggest that structural features inherited from group I ribozymes have undergone speciation due to profound changes in molecular selection pressure, ultimately giving rise to an original branching ribozyme family. The structures elucidate the role of key elements that regulate the activity of the LC ribozyme by conformational switching and suggest a mechanism by which the signal for branching is transmitted to the catalytic core. The structures also show how conserved interactions twist residues, forming the lariat to join chemical groups involved in branching. PMID:24821772

  3. Actin filament barbed-end capping activity in neutrophil lysates: the role of capping protein-beta 2.

    PubMed

    DiNubile, M J; Cassimeris, L; Joyce, M; Zigmond, S H

    1995-12-01

    A barbed-end capping activity was found in high speed supernates of neutrophils lysed in submicromolar calcium. In dilute supernate (> or = 100-fold dilution of cytoplasm), this activity accounted for most of the inhibition of barbed-end elongation of pyrenyl-G-actin from spectrin-F-actin seeds. Pointed-end elongation from gelsolin-capped F-actin seeds was not inhibited at comparable concentrations of supernate, thus excluding actin monomer sequestration as a cause of the observed inhibition. Most of the capping activity was due to capping protein-beta 2 (a homologue of cap Z). Thus, while immunoadsorption of > or = 95% of the gelsolin in the supernate did not decrease capping activity, immunoadsorption of capping protein-beta 2 reduced capping activity proportionally to the amount of capping protein-beta 2 adsorbed. Depletion of > 90% of capping protein-beta 2 from the supernate removed 90% of its capping activity. The functional properties of the capping activity were defined. The dissociation constant for binding to barbed ends (determined by steady state and kinetic analyses) was approximately 1-2 nM; the on-rate of capping was between 7 x 10(5) and 5 x 10(6) M-1 s-1; and the off-rate was approximately 2 x 10(-3) s-1. The concentration of capper free in the intact cell (determined by adsorption of supernate with spectrin-actin seeds) was estimated to be approximately 1-2 microM. Thus, there appeared to be enough high affinity capper to cap all the barbed ends in vivo. Nevertheless, immediately after lysis with detergent, neutrophils contained sites that nucleate barbed-end elongation of pyrenyl-G-actin. These barbed ends subsequently become capped with a time course and concentration dependence similar to that of spectrin-F-actin seeds in high speed supernates. These observations suggest that, despite the excess of high affinity capper, some ends either are not capped in vivo or are transiently uncapped upon lysis and dilution. PMID:8590796

  4. Interannual variability of Mars' south polar CAP

    NASA Astrophysics Data System (ADS)

    James, P. B.; Malolepszy, K. M.; Martin, L. J.

    1987-08-01

    Published observational data on the seasonal recession of the south polar cap on Mars (covering the period 1903-1977) are compiled in tables and graphs and analyzed statistically. The basic data set (photographic observations obtained at Lowell Observatory) of Fischbacher et al. (1960) and James and Lumme (1982) and the reduction procedures described by Baum and Martin (1973) are employed, and Viking data from 1977 are used for comparison; the early onset (relative to the mean) of the 1956 recession is characterized in detail. A list of photographically documented large dust storms is provided, and it is suggested that in years with early spring storms, recession may be slower than in years without such storms.

  5. Optimized capping layers for EUV multilayers

    DOEpatents

    Bajt, Sasa; Folta, James A.; Spiller, Eberhard A.

    2004-08-24

    A new capping multilayer structure for EUV-reflective Mo/Si multilayers consists of two layers: A top layer that protects the multilayer structure from the environment and a bottom layer that acts as a diffusion barrier between the top layer and the structure beneath. One embodiment combines a first layer of Ru with a second layer of B.sub.4 C. Another embodiment combines a first layer of Ru with a second layer of Mo. These embodiments have the additional advantage that the reflectivity is also enhanced. Ru has the best oxidation resistance of all materials investigated so far. B.sub.4 C is an excellent barrier against silicide formation while the silicide layer formed at the Si boundary is well controlled.

  6. Glass microstructure capping and bonding techniques.

    PubMed

    Mazurczyk, Radoslaw; Mansfield, Colin D; Lygan, Marcin

    2013-01-01

    The capping of microfluidic features fabricated in glass substrates is achievable by various technological methods. Of the entire spectrum of possibilities (gluing, glass bonding via intermediate layers, pressure or plasma-assisted glass bonding, etc.) a detailed description of three techniques is presented here. The first is a low temperature PDMS-glass adhesion bonding, the second is medium temperature pressure assisted glass-glass bonding, and finally, high temperature glass-glass fusion bonding. All these protocols allow completion of the manufacturing process for a fully enclosed microfluidic chip. Nevertheless, as they are complementary rather than competing methods, they effectively extend the range of tools available to fabricate lab-on-a-chip microdevices. Each has its own merits and each could feasibly be used at different developmental stages of a given microfluidic device.

  7. Glaciers and ice caps outside Greenland

    USGS Publications Warehouse

    Sharp, Marin; Wolken, G.; Burgess, D.; Cogley, J.G.; Copland, L.; Thomson, L.; Arendt, A.; Wouters, B.; Kohler, J.; Andreassen, L.M.; O'Neel, Shad; Pelto, M.

    2015-01-01

    Mountain glaciers and ice caps cover an area of over 400 000 km2 in the Arctic, and are a major influence on global sea level (Gardner et al. 2011, 2013; Jacob et al. 2012). They gain mass by snow accumulation and lose mass by meltwater runoff. Where they terminate in water (ocean or lake), they also lose mass by iceberg calving. The climatic mass balance (Bclim, the difference between annual snow accumulation and annual meltwater runoff) is a widely used index of how glaciers respond to climate variability and change. The total mass balance (ΔM) is defined as the difference between annual snow accumulation and annual mass losses (by iceberg calving plus runoff).

  8. In situ capping for size control of monochalcogenides (ZnS, CdS, and SnS) nanocrystals produced by anaerobic metal-reducing bacteria

    DOE PAGESBeta

    Jang, Gyoung Gug; Jacobs, Christopher B.; Ivanov, Ilia N.; Joshi, Pooran C.; Meyer, III, Harry M.; Kidder, Michelle; Armstrong, Beth L.; Datskos, Panos G.; Graham, David E.; Moon, Ji -Won

    2015-07-24

    Metal monochalcogenide quantum dot nanocrystals of ZnS, CdS and SnS were prepared by anaerobic, metal-reducing bacteria using in situ capping by oleic acid or oleylamine. Furthermore, the capping agent preferentially adsorbs on the surface of the nanocrystal, suppressing the growth process in the early stages, thus leading to production of nanocrystals with a diameter of less than 5 nm.

  9. Geochemical evolution of a fractured zone in the cap rock of an underground carbon storage site

    NASA Astrophysics Data System (ADS)

    Vialle, S.; Druhan, J. L.; Maher, K.

    2013-12-01

    Assessment and management of environmental risks associated with underground storage of CO2 in geological systems is essential for the commercial deployment of this technology. A major risk is leakage of the CO2 from its storage reservoir, through wellbores, and along faults and fractures in the cap rock. The geochemical reactions likely to take place as CO2 leaks through a damage zone and their impact on cap rock integrity still need to be better understood and quantified. Should CO2 leakage occur, geochemical reactions would govern the environmental impact on shallow groundwater aquifers and could provide an indication of the leak prior to surface-based monitoring techniques. We used the reactive transport code TOUGH2/TOUGHREACT to model a leakage scenario through a fractured cap rock. Since geochemical reactions will strongly depend upon the local hydrodynamics of the CO2 leak, the first step of the study is to provide an appropriate physical representation of fluid flow through the system. Typically, for a low porosity rock formation, a fault/damaged zone system is composed of a core of low permeability and a damage zone with second-order fractures whose density decreases with distance from the fault core. Permeability is thus increased along the fault plane and laterally decreases down to the permeability value of the undamaged cap rock. Appropriate scaling relationships (e.g., and analytical expression of for permeability as a function of fracture aperture and fracture density), effective physical parameters as well as constitutive relationships are carefully chosen to model the fractured system, treated as an equivalent porous medium. The cap rock is initially saturated with brine (salinity of 0.15 in mass fraction) and due to overpressure in the lower storage reservoir, CO2 migrates through the damage zone. Geochemical reactions involve both salt precipitation due to the partitioning of H2O and CO2 between liquid and gas phases as well as well reactions

  10. The quiet time polar cap: DE 1 observations and conceptual model

    SciTech Connect

    Burch, J.L. ); Saflekos, N.A. ); Gurnett, D.A.; Frank, L.A. ); Craven, J.D. )

    1992-12-01

    Auroral activity increases over the polar caps during quiet times, which are associated with northward interplanetary magnetic field (IMF) components. Polar cap auroras (Sun-aligned arcs, theta auroras, and horse collar auroras) occur under these conditions. DE 1 data have provided partial characterization of these events. A conceptual northward IMF merging model containing lobe cells, merging cells, and viscous cells is shown to be consistent with the observations. As the IMF becomes more northward, the polar arc configuration changes from the horse collar pattern to the theta aurora pattern in the model, and this is shown to be generally true for the set of published data on these phenomena. The model involves dayside merging both at high latitudes on open field lines and at lower latitudes on closed field lines. The ratio between the merged flux produced by the high-latitude merging to that produced by the lower-latitude merging increases as the IMF becomes more northward. Two types of open field lines, equator-crossing and non-equator-crossing, are produced by the higher- and lower-latitude merging, respectively. The equator-crossing field lines have a strong azimuthal component of convection as they flow around the magnetopause, while the non-equator-crossing field lines can convect more or less directly across the polar cap, leading to an antisunward flow channel across the central polar cap. This antisunward flow region grows as the IMF becomes less northward, causing dual polar cap arcs to spread out into the horse collar configuration.

  11. Influence of dimensionality and interface type on optical and electronic properties of CdS/ZnS core-shell nanocrystals—A first-principles study

    SciTech Connect

    Kocevski, V. E-mail: vancho.kocevski@physics.uu.se; Eriksson, O.; Gerard, C.; Rusz, J.; Sarma, D. D.

    2015-10-28

    Semiconducting nanocrystals (NCs) have become one of the leading materials in a variety of applications, mainly due to their size tunable band gap and high intensity emission. Their photoluminescence (PL) properties can be notably improved by capping the nanocrystals with a shell of another semiconductor, making core-shell structures. We focus our study on the CdS/ZnS core-shell nanocrystals that are closely related to extensively studied CdSe/CdS NCs, albeit exhibiting rather different photoluminescence properties. We employ density functional theory to investigate the changes in the electronic and optical properties of these nanocrystals with size, core/shell ratio, and interface structure between the core and the shell. We have found that both the lowest unoccupied eigenstate (LUES) and the highest occupied eigenstate (HOES) wavefunction (WF) are localized in the core of the NCs, with the distribution of the LUES WF being more sensitive to the size and the core/shell ratio. We show that the radiative lifetimes are increasing, and the Coulomb interaction energies decrease with increasing NC size. Furthermore, we investigated the electronic and optical properties of the NCs with different interfaces between the core and the shell and different core types. We find that the different interfaces and core types have rather small influence on the band gaps and the absorption indexes, as well as on the confinement of the HOES and LUES WFs. Also the radiative lifetimes are found to be only slightly influenced by the different structural models. In addition, we compare these results with the previous results for CdSe/CdS NCs, reflecting the different PL properties of these two types of NCs. We argue that the difference in their Coulomb interaction energies is one of the main reasons for their distinct PL properties.

  12. Analysis of the Staphylococcus aureus capsule biosynthesis pathway in vitro: characterization of the UDP-GlcNAc C6 dehydratases CapD and CapE and identification of enzyme inhibitors.

    PubMed

    Li, Wenjin; Ulm, Hannah; Rausch, Marvin; Li, Xue; O'Riordan, Katie; Lee, Jean C; Schneider, Tanja; Müller, Christa E

    2014-11-01

    Polysaccharide capsules significantly contribute to virulence of invasive pathogens, and inhibition of capsule biosynthesis may offer a valuable strategy for novel anti-infective treatment. We purified and characterized the enzymes CapD and CapE of the Staphylococcus aureus serotype 5 biosynthesis cluster, which catalyze the first steps in the synthesis of the soluble capsule precursors UDP-D-FucNAc and UDP-L-FucNAc, respectively. CapD is an integral membrane protein and was obtained for the first time in a purified, active form. A capillary electrophoresis (CE)-based method applying micellar electrokinetic chromatography (MEKC) coupled with UV detection at 260 nm was developed for functional characterization of the enzymes using a fused-silica capillary, electrokinetic injection, and dynamic coating with polybrene at pH 12.4. The limits of detection for the CapD and CapE products UDP-2-acetamido-2,6-dideoxy-α-D-xylo-hex-4-ulose and UDP-2-acetamido-2,6-dideoxy-β-L-arabino-hex-4-ulose, respectively, were below 1 μM. Using this new, robust and sensitive method we performed kinetic studies for CapD and CapE and screened a compound library in search for enzyme inhibitors. Several active compounds were identified and characterized, including suramin (IC50 at CapE 1.82 μM) and ampicillin (IC50 at CapD 40.1 μM). Furthermore, the cell wall precursors UDP-D-MurNAc-pentapeptide and lipid II appear to function as inhibitors of CapD enzymatic activity, suggesting an integrated mechanism of regulation for cell envelope biosynthesis pathways in S. aureus. Corroborating the in vitro findings, staphylococcal cells grown in the presence of subinhibitory concentrations of ampicillin displayed drastically reduced CP production. Our studies contribute to a profound understanding of the capsule biosynthesis in pathogenic bacteria. This approach may lead to the identification of novel anti-virulence and antibiotic drugs.

  13. Analysis of the Staphylococcus aureus capsule biosynthesis pathway in vitro: characterization of the UDP-GlcNAc C6 dehydratases CapD and CapE and identification of enzyme inhibitors.

    PubMed

    Li, Wenjin; Ulm, Hannah; Rausch, Marvin; Li, Xue; O'Riordan, Katie; Lee, Jean C; Schneider, Tanja; Müller, Christa E

    2014-11-01

    Polysaccharide capsules significantly contribute to virulence of invasive pathogens, and inhibition of capsule biosynthesis may offer a valuable strategy for novel anti-infective treatment. We purified and characterized the enzymes CapD and CapE of the Staphylococcus aureus serotype 5 biosynthesis cluster, which catalyze the first steps in the synthesis of the soluble capsule precursors UDP-D-FucNAc and UDP-L-FucNAc, respectively. CapD is an integral membrane protein and was obtained for the first time in a purified, active form. A capillary electrophoresis (CE)-based method applying micellar electrokinetic chromatography (MEKC) coupled with UV detection at 260 nm was developed for functional characterization of the enzymes using a fused-silica capillary, electrokinetic injection, and dynamic coating with polybrene at pH 12.4. The limits of detection for the CapD and CapE products UDP-2-acetamido-2,6-dideoxy-α-D-xylo-hex-4-ulose and UDP-2-acetamido-2,6-dideoxy-β-L-arabino-hex-4-ulose, respectively, were below 1 μM. Using this new, robust and sensitive method we performed kinetic studies for CapD and CapE and screened a compound library in search for enzyme inhibitors. Several active compounds were identified and characterized, including suramin (IC50 at CapE 1.82 μM) and ampicillin (IC50 at CapD 40.1 μM). Furthermore, the cell wall precursors UDP-D-MurNAc-pentapeptide and lipid II appear to function as inhibitors of CapD enzymatic activity, suggesting an integrated mechanism of regulation for cell envelope biosynthesis pathways in S. aureus. Corroborating the in vitro findings, staphylococcal cells grown in the presence of subinhibitory concentrations of ampicillin displayed drastically reduced CP production. Our studies contribute to a profound understanding of the capsule biosynthesis in pathogenic bacteria. This approach may lead to the identification of novel anti-virulence and antibiotic drugs. PMID:25023075

  14. Lead and cadmium in fruiting bodies of macrofungi in the vicinity of a lead smelter.

    PubMed

    Lepsová, A; Král, R

    1988-10-15

    The concentrations of lead and cadmium in the fruiting bodies of mycorrhizal and edible macrofungi (Basidiomycetes, Agaricales) were measured in the vicinity of a lead smelter. Very high concentrations of both metals were found 1 km from the stack, and elevated concentrations were observed up to a distance of 4.5 km. The dependence of the concentrations on the distance from the stack were approximated by an exponential function, the extrapolation of which showed that only at a distance of 6 km did the concentrations approach those reported from an area in the Krusné Hory Mountains with a medium level of air pollution. The concentrations of lead were slightly higher in the caps than in the stems of the fungal fruiting bodies from the sites close to the smelters; at a distance of 1.7 km they were the same, and at greater distances the lead concentrations in the caps were slightly lower than those in the stems. The cap/stem concentration ratio for cadmium does not exhibit any change with distance. The different behaviour of the two metals can be explained in terms of the lower mobility of Pb2+ ions. Because of their lead and cadmium contents, edible mycorrhizal fungi picked within a distance of 0.6 km of the stack can be toxic to man if eaten often in quantities that are usual in Czechoslovakia. PMID:3238420

  15. Cold atmospheric plasma (CAP) changes gene expression of key molecules of the wound healing machinery and improves wound healing in vitro and in vivo.

    PubMed

    Arndt, Stephanie; Unger, Petra; Wacker, Eva; Shimizu, Tetsuji; Heinlin, Julia; Li, Yang-Fang; Thomas, Hubertus M; Morfill, Gregor E; Zimmermann, Julia L; Bosserhoff, Anja-Katrin; Karrer, Sigrid

    2013-01-01

    Cold atmospheric plasma (CAP) has the potential to interact with tissue or cells leading to fast, painless and efficient disinfection and furthermore has positive effects on wound healing and tissue regeneration. For clinical implementation it is necessary to examine how CAP improves wound healing and which molecular changes occur after the CAP treatment. In the present study we used the second generation MicroPlaSter ß® in analogy to the current clinical standard (2 min treatment time) in order to determine molecular changes induced by CAP using in vitro cell culture studies with human fibroblasts and an in vivo mouse skin wound healing model. Our in vitro analysis revealed that the CAP treatment induces the expression of important key genes crucial for the wound healing response like IL-6, IL-8, MCP-1, TGF-ß1, TGF-ß2, and promotes the production of collagen type I and alpha-SMA. Scratch wound healing assays showed improved cell migration, whereas cell proliferation analyzed by XTT method, and the apoptotic machinery analyzed by protein array technology, was not altered by CAP in dermal fibroblasts. An in vivo wound healing model confirmed that the CAP treatment affects above mentioned genes involved in wound healing, tissue injury and repair. Additionally, we observed that the CAP treatment improves wound healing in mice, no relevant side effects were detected. We suggest that improved wound healing might be due to the activation of a specified panel of cytokines and growth factors by CAP. In summary, our in vitro human and in vivo animal data suggest that the 2 min treatment with the MicroPlaSter ß® is an effective technique for activating wound healing relevant molecules in dermal fibroblasts leading to improved wound healing, whereas the mechanisms which contribute to these observed effects have to be further investigated.

  16. Temperature Distribution within a Cold Cap during Nuclear Waste Vitrification

    SciTech Connect

    Dixon, Derek R.; Schweiger, Michael J.; Riley, Brian J.; Pokorny, Richard; Hrma, Pavel R.

    2015-07-21

    The kinetics of the feed-to-glass conversion affects the waste vitrification rate in an electric melter. The primary area of interest in this conversion process is the cold cap, a layer of reacting feed on top of molten glass. Knowing the temperature profile within a cold cap will help determine its characteristics and relate them to the rate of glass production. The work presented here provides an experimental determination of the temperature distribution within the cold cap. Since a direct measurement of the temperature field within the cold cap is impracticable, an indirect method was developed where the textural features in a laboratory-made cold cap with a high-level waste feed were mapped as a function of position using optical microscopy, scanning electron microscopy, energy dispersive spectroscopy, and X-ray diffraction. To correlate the temperature distribution to microstructures within the cold cap, microstructures were identified of individual feed samples that were heat treated to set temperatures between 400°C and 1200°C and quenched. The temperature distribution within the cold cap was then established by correlating cold-cap regions with the feed samples of nearly identical structures and was compared with the temperature profile from a mathematical model.

  17. 47 CFR 61.41 - Price cap requirements generally.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... party to a merger, acquisition, or similar transaction shall continue to be subject to price cap... no later than one year following the effective date of such merger, acquisition, or similar... subject to price cap regulation, as that term is defined in § 61.3(ee), which are involved in...

  18. IN SITU REMEDIATION OF CONTAMINATED SEDIMENTS - ACTIVE CAPPING TECHNOLOGY

    SciTech Connect

    Knox, A.; Roberts, J.; Paller, M.; Reible, D.

    2010-09-02

    Active capping is a relatively new approach for treating contaminated sediments. It involves applying chemically reactive amendments to the sediment surface. The main role of active caps is to stabilize contaminants in contaminated sediments, lower the bioavailable pool of contaminants, and reduce the release of contaminants to the water column. Metals are common contaminants in many marine and fresh water environments as a result of industrial and military activities. The mobile, soluble forms of metals are generally considered toxic. Induced chemical precipitation of these metals can shift toxic metals from the aqueous phase to a solid, precipitated phase which is often less bioavailable. This approach can be achieved through application of sequestering agents such as rock phosphates, organoclays, zeolites, clay minerals, and biopolymers (e.g., chitosan) in active capping technology. Active capping holds great potential for a more permanent solution that avoids residual risks resulting from contaminant migration through the cap or breaching of the cap. In addition to identifying superior active capping agents, research is needed to optimize application techniques, application rates, and amendment combinations that maximize sequestration of contaminants. A selected set of active capping treatment technologies has been demonstrated at a few sites, including a field demonstration at the Savannah River Site, Aiken, SC. This demonstration has provided useful information on the effects of sequestering agents on metal immobilization, bioavailability, toxicity, and resistance to mechanical disturbance.

  19. Better End-Cap Processing for Oxidation-Resistant Polyimides

    NASA Technical Reports Server (NTRS)

    Meador, Mary Ann B.; Frimer, Aryeh A.

    2004-01-01

    A class of end-cap compounds that increase the thermo-oxidative stab ility of polyimides of the polymerization of monomeric reactants (PM R) type has been extended. In addition, an improved processing proto col for this class of end-cap compounds has been invented.

  20. Interfacial strain effect on type-I and type-II core/shell quantum dots

    NASA Astrophysics Data System (ADS)

    Gheshlaghi, Negar; Pisheh, Hadi Sedaghat; Karim, M. Rezaul; Malkoc, Derya; Ünlü, Hilmi

    2016-09-01

    A comparative experimental and theoretical study on the calculation of capped core diameter in ZnSe/ZnS, CdSe/Cd(Zn)S type-I and ZnSe/CdS type-II core/shell nanocrystals is presented. The lattice mismatch induced interface strain between core and shell was calculated from continuum elastic theory and applied in effective mass approximation method to obtain the corresponding capped core diameter. The calculated results were compared with diameter of bare cores (CdSe and ZnSe) from transmission electron microscopy images to obtain the amount of the stretched or squeezed core after deposition of tensile or compressive shells. The result of the study showed that the core is squeezed in ZnSe/ZnS and CdSe/Cd(Zn)S after compressive shell and stretched in ZnSe/CdS after tensile shell deposition. The stretched and squeezed amount of the capped core found to be in proportion with lattice mismatch amount in the core/shell structure.

  1. A Cost and Performance System (CAPS) in a Federal agency

    NASA Technical Reports Server (NTRS)

    Huseonia, W. F.; Penton, P. G.

    1994-01-01

    Cost and Performance System (CAPS) is an automated system used from the planning phase through implementation to analysis and documentation. Data is retrievable or available for analysis of cost versus performance anomalies. CAPS provides a uniform system across intra- and international elements. A common system is recommended throughout an entire cost or profit center. Data can be easily accumulated and aggregated into higher levels of tracking and reporting of cost and performance.The level and quality of performance or productivity is indicated in the CAPS model and its process. The CAPS model provides the necessary decision information and insight to the principal investigator/project engineer for a successful project management experience. CAPS provides all levels of management with the appropriate detailed level of data.

  2. Involvement of prostaglandins F/sub 2. cap alpha. / and E/sub 1/ with rabbit endometrium

    SciTech Connect

    Orlicky, D.J.

    1985-01-01

    Several growth factors and hormones are thought to play a role in the growth control of endometrial cells. The authors have shown that prostaglandin F/sub 2..-->../ (PGF/sub 2..cap alpha../) is a growth factor for primary cultures of rabbit endometrium cultured in chemically-defined serum-free medium and that prostaglandin E/sub 1/ (PGE/sub 1/) antagonizes the PGF/sub 2..-->../ induction of growth. Both (/sup 3/H)PGF/sub 2..cap alpha../ and (/sup 3/H)PGE/sub 1/ bind in a time and temperature dependent, dissociable, saturable and specific manner. The binding of (/sup 3/H)PGF/sub 2..cap alpha../ and (/sup 3/H)PGE/sub 1/ can be both down and up regulated and is enzyme sensitive. PGE /sub 1/ stimulates intracellular cAMP synthesis and accumulation in a time and concentration dependent manner. PGF/sub 2..cap alpha../ probably exerts its effects through an amiloride-sensitive intermediate. Both PGF/sub 2..cap alpha../ and PGE/sub 1/ are constitutively synthesized by these primary cultures, and they have shown this synthesis to be both drug and hormone sensitive. They hypothesize that it is the ratio, rather than the absolute quantities, of PGF/sub 2..cap alpha../ and PGE/sub 1/ which is of more importance in the regulation of endometrial cell growth. Furthermore, they believe this regulation of endometrial growth plays a role in control of proliferation during the decidual response and that a derangement in the ratio of these prostaglandins may lead to either infertility or hyperplasia. The ability of these cultures to synthesize prostaglandins in a hormonally regulatable manner may be of importance in the study of dysmenorrhea and uterine cramping as caused by the myometrial contracting prostaglandin, PGF/sub 2..cap alpha../.

  3. Rocket measurements within a polar cap arc - Plasma, particle, and electric circuit parameters

    NASA Technical Reports Server (NTRS)

    Weber, E. J.; Ballenthin, J. O.; Basu, S.; Carlson, H. C.; Hardy, D. A.; Maynard, N. C.; Kelley, M. C.; Fleischman, J. R.; Pfaff, R. F.

    1989-01-01

    Results are presented from the Polar Ionospheric Irregularities Experiment (PIIE), conducted from Sondrestrom, Greenland, on March 15, 1985, designed for an investigation of processes which lead to the generation of small-scale (less than 1 km) ionospheric irregularities within polar-cap F-layer auroras. An instrumented rocket was launched into a polar cap F layer aurora to measure energetic electron flux, plasma, and electric circuit parameters of a sun-aligned arc, coordinated with simultaneous measurements from the Sondrestrom incoherent scatter radar and the AFGL Airborne Ionospheric Observatory. Results indicated the existence of two different generation mechanisms on the dawnside and duskside of the arc. On the duskside, parameters are suggestive of an interchange process, while on the dawnside, fluctuation parameters are consistent with a velocity shear instability.

  4. 30 CFR 250.1157 - How do I receive approval to produce gas-cap gas from an oil reservoir with an associated gas cap?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... gas from an oil reservoir with an associated gas cap? 250.1157 Section 250.1157 Mineral Resources... do I receive approval to produce gas-cap gas from an oil reservoir with an associated gas cap? (a... from each completion in an oil reservoir that is known to have an associated gas cap. (2) To...

  5. Dual-core antiresonant hollow core fibers.

    PubMed

    Liu, Xuesong; Fan, Zhongwei; Shi, Zhaohui; Ma, Yunfeng; Yu, Jin; Zhang, Jing

    2016-07-25

    In this work, dual-core antiresonant hollow core fibers (AR-HCFs) are numerically demonstrated, based on our knowledge, for the first time. Two fiber structures are proposed. One is a composite of two single-core nested nodeless AR-HCFs, exhibiting low confinement loss and a circular mode profile in each core. The other has a relatively simple structure, with a whole elliptical outer jacket, presenting a uniform and wide transmission band. The modal couplings of the dual-core AR-HCFs rely on a unique mechanism that transfers power through the air. The core separation and the gap between the two cores influence the modal coupling strength. With proper designs, both of the dual-core fibers can have low phase birefringence and short modal coupling lengths of several centimeters.

  6. cap alpha. -skeletal and. cap alpha. -cardiac actin genes are coexpressed in adult human skeletal muscle and heart

    SciTech Connect

    Gunning, P.; Ponte, P.; Blau, H.; Kedes, L.

    1983-11-01

    The authors determined the actin isotypes encoded by 30 actin cDNA clones previously isolated from an adult human muscle cDNA library. Using 3' untranslated region probes, derived from ..cap alpha.. skeletal, ..beta..- and ..gamma..-actin cDNAs and from an ..cap alpha..-cardiac actin genomic clone, they showed that 28 of the cDNAs correspond to ..cap alpha..-skeletal actin transcripts. Unexpectedly, however, the remaining two cDNA clones proved to derive from ..cap alpha..-cardiac actin mRNA. Sequence analysis confirmed that the two skeletal muscle ..cap alpha..-cardiac actin cDNAs are derived from transcripts of the cloned ..cap alpha..-cardiac actin gene. Comparison of total actin mRNA levels in adult skeletal muscle and adult heart revealed that the steady-state levels in skeletal muscle are about twofold greater, per microgram of total cellular RNA, than those in heart. Thus, in skeletal muscle and in heart, both of the sarcomeric actin mRNA isotypes are quite abundant transcripts. They conclude that ..cap alpha..-skeletal and ..cap alpha..-cardiac actin genes are coexpressed as an actin pair in human adult striated muscles. Since the smooth-muscle actins (aortic and stomach) and the cytoplasmic actins (..beta.. and ..gamma..) are known to be coexpressed in smooth muscle and nonmuscle cells, respectively, they postulate that coexpression of actin pairs may be a common feature of mammalian actin gene expression in all tissues.

  7. Development, genetic mapping and QTL association of cotton PHYA, PHYB, and HY5-specific CAPS and dCAPS markers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Among SNP markers that become increasingly valuable in molecular breeding of crop plants are the CAP and dCAP markers derived from the genes of interest. To date, the number of such gene-based markers is small in polyploid crop plants such as tetraploid cotton that has A and D subgenomes. The obje...

  8. Structural analysis of human 2'-O-ribose methyltransferases involved in mRNA cap structure formation

    NASA Astrophysics Data System (ADS)

    Smietanski, Miroslaw; Werner, Maria; Purta, Elzbieta; Kaminska, Katarzyna H.; Stepinski, Janusz; Darzynkiewicz, Edward; Nowotny, Marcin; Bujnicki, Janusz M.

    2014-01-01

    The 5' cap of human messenger RNA contains 2'-O-methylation of the first and often second transcribed nucleotide that is important for its processing, translation and stability. Human enzymes that methylate these nucleotides, termed CMTr1 and CMTr2, respectively, have recently been identified. However, the structures of these enzymes and their mechanisms of action remain unknown. In the present study, we solve the crystal structures of the active CMTr1 catalytic domain in complex with a methyl group donor and a capped oligoribonucleotide, thereby revealing the mechanism of specific recognition of capped RNA. This mechanism differs significantly from viral enzymes, thus providing a framework for their specific targeting. Based on the crystal structure of CMTr1, a comparative model of the CMTr2 catalytic domain is generated. This model, together with mutational analysis, leads to the identification of residues involved in RNA and methyl group donor binding.

  9. Structural analysis of human 2′-O-ribose methyltransferases involved in mRNA cap structure formation

    PubMed Central

    Smietanski, Miroslaw; Werner, Maria; Purta, Elzbieta; Kaminska, Katarzyna H.; Stepinski, Janusz; Darzynkiewicz, Edward; Nowotny, Marcin; Bujnicki, Janusz M.

    2014-01-01

    The 5′ cap of human messenger RNA contains 2′-O-methylation of the first and often second transcribed nucleotide that is important for its processing, translation and stability. Human enzymes that methylate these nucleotides, termed CMTr1 and CMTr2, respectively, have recently been identified. However, the structures of these enzymes and their mechanisms of action remain unknown. In the present study, we solve the crystal structures of the active CMTr1 catalytic domain in complex with a methyl group donor and a capped oligoribonucleotide, thereby revealing the mechanism of specific recognition of capped RNA. This mechanism differs significantly from viral enzymes, thus providing a framework for their specific targeting. Based on the crystal structure of CMTr1, a comparative model of the CMTr2 catalytic domain is generated. This model, together with mutational analysis, leads to the identification of residues involved in RNA and methyl group donor binding. PMID:24402442

  10. Key Role of End-Capping Groups in Optoelectronic Properties of Poly-p-phenylene Cation Radicals

    PubMed Central

    2015-01-01

    Poly-p-phenylenes (PPs) are prototype systems for understanding the charge transport in π-conjugated polymers. In a combined computational and experimental study, we demonstrate that the smooth evolution of redox and optoelectronic properties of PP cation radicals toward the polymeric limit can be significantly altered by electron-donating iso-alkyl and iso-alkoxy end-capping groups. A multiparabolic model (MPM) developed and validated here rationalizes this unexpected effect by interplay of the two modes of hole stabilization: due to the framework of equivalent p-phenylene units and due to the electron-donating end-capping groups. A symmetric, bell-shaped hole in unsubstituted PPs becomes either slightly skewed and shifted toward an end of the molecule in iso-alkyl-capped PPs or highly deformed and concentrated on a terminal unit in PPs with strongly electron-donating iso-alkoxy capping groups. The MPM shows that the observed linear 1/n evolution of the PP cation radical properties toward the polymer limit originates from the hole stabilization due to the growing chain of p-phenylene units, while shifting of the hole toward electron-donating end-capping groups leads to early breakdown of these 1/n dependencies. These insights, along with the readily applicable and flexible multistate parabolic model, can guide studies of complex donor–spacer–acceptor systems and doped molecular wires to aid the design of the next generation materials for long-range charge transport and photovoltaic applications. PMID:25264475

  11. Cap0037, a Novel Global Regulator of Clostridium acetobutylicum Metabolism

    PubMed Central

    Nguyen, Ngoc-Phuong-Thao; Linder, Sonja; Flitsch, Stefanie K.; Schiel-Bengelsdorf, Bettina; Dürre, Peter

    2016-01-01

    ABSTRACT An operon comprising two genes, CA_P0037 and CA_P0036, that encode proteins of unknown function that were previously shown to be highly expressed in acidogenic cells and repressed in solventogenic and alcohologenic cells is located on the pSOL1 megaplasmid of Clostridium acetobutylicum upstream of adhE2. A CA_P0037::int (189/190s) mutant in which an intron was inserted at position 189/190 in the sense strand of CA_P0037 was successfully generated by the Targetron technique. The resultant mutant showed significantly different metabolic flux patterns in acidogenic (producing mainly lactate, butyrate, and butanol) and alcohologenic (producing mainly butyrate, acetate, and lactate) chemostat cultures but not in solventogenic or batch cultures. Transcriptomic investigation of the CA_P0037::int (189/190s) mutant showed that inactivation of CA_P0037 significantly affected the expression of more than 258 genes under acidogenic conditions. Surprisingly, genes belonging to the Fur regulon, involved in iron transport (CA_C1029-CA_C1032), or coding for the main flavodoxin (CA_C0587) were the most significantly expressed genes under all conditions, whereas fur (coding for the ferric uptake regulator) gene expression remained unchanged. Furthermore, most of the genes of the Rex regulon, such as the adhE2 and ldhA genes, and of the PerR regulon, such as rbr3A-rbr3B and dfx, were overexpressed in the mutant. In addition, the whole CA_P0037-CA_P0036 operon was highly expressed under all conditions in the CA_P0037::int (189/190s) mutant, suggesting a self-regulated expression mechanism. Cap0037 was shown to bind to the CA_P0037-CA_P0036 operon, sol operon, and adc promoters, and the binding sites were determined by DNA footprinting. Finally, a putative Cap0037 regulon was generated using a bioinformatic approach. PMID:27703070

  12. Physics of Stratocumulus Top (POST): turbulent mixing across capping inversion

    NASA Astrophysics Data System (ADS)

    Malinowski, S. P.; Gerber, H.; Jen-LaPlante, I.; Kopec, M. K.; Kumala, W.; Nurowska, K.; Chuang, P. Y.; Khelif, D.; Haman, K. E.

    2013-06-01

    High spatial resolution measurements of temperature and liquid water content, accompanied by moderate resolution measurements of humidity and turbulence, collected during the Physics of Stratocumulus Top experiment are analyzed. Two thermodynamically, meteorologically and even optically different cases are investigated. An algorithmic division of the cloud top region into layers is proposed. Analysis of dynamic stability across these layers leads to the conclusion that the inversion capping the cloud and the cloud top region are turbulent due to the wind shear, which is strong enough to compensate for high static stability of the inversion. The thickness of this mixing layer adapts to wind and temperature jumps such that the gradient Richardson number stays close to its critical value. Turbulent mixing governs transport across the inversion, but the consequences of this mixing depend on the thermodynamic properties of cloud top and free troposphere. The effects of buoyancy-sorting of the mixed parcels in the cloud top region are different in conditions that permit or prevent cloud top entrainment instability. Removal of negatively buoyant air from the cloud top is observed in the first case, while buildup of the diluted cloud top layer is observed in the second one.

  13. Physics of Stratocumulus Top (POST): turbulent mixing across capping inversion

    NASA Astrophysics Data System (ADS)

    Malinowski, S. P.; Gerber, H.; Jen-La Plante, I.; Kopec, M. K.; Kumala, W.; Nurowska, K.; Chuang, P. Y.; Khelif, D.; Haman, K. E.

    2013-12-01

    High spatial resolution measurements of temperature and liquid water content, accompanied by moderate-resolution measurements of humidity and turbulence, collected during the Physics of Stratocumulus Top experiment are analyzed. Two thermodynamically, meteorologically and even optically different cases are investigated. An algorithmic division of the cloud-top region into layers is proposed. Analysis of dynamic stability across these layers leads to the conclusion that the inversion capping the cloud and the cloud-top region is turbulent due to the wind shear, which is strong enough to overcome the high static stability of the inversion. The thickness of this mixing layer adapts to wind and temperature jumps such that the gradient Richardson number stays close to its critical value. Turbulent mixing governs transport across the inversion, but the consequences of this mixing depend on the thermodynamic properties of cloud top and free troposphere. The effects of buoyancy sorting of the mixed parcels in the cloud-top region are different in conditions that permit or prevent cloud-top entrainment instability. Removal of negatively buoyant air from the cloud top is observed in the first case, while buildup of the diluted cloud-top layer is observed in the second one.

  14. Enhanced oil recovery. Improved reservoir evaluation object of sponge coring process

    SciTech Connect

    Mickey, V.

    1981-04-01

    Oil saturation data determined by core analysis have improved. One result is the development of the sponge coring process. In the sponge coring method, the core sample is taken in much the same way as in conventional coring. The major difference is the porous, hard sponge that lines the core barrel. The sponge is so porous (approximately 80%) that cigarette smoke can be blown through it. It has one full darcy permeability and is oil-wet. The sponge is inside a thin polyvinyl chloride liner with small perforations in it. As the sponge core barrel is run into the hole, the sponge becomes wet with drilling fluid, usually water. Any oil in the core being forced out by the water and the reduction in pressure as the core is brought to surface is caught by the sponge. Since it is oil-wet the oil is retained. But water is forced out the small perforations in the liner. At the surface the 20-ft core is cut into 5-ft sections and put into special containers filled with fluid from the formation. That keeps the core in standard condition. Even much of the gas in solution remains in the core. This is noted during capping operations as the cap is forced back until the glue on it holds and seals the tube.

  15. EPA'S FIELD DEMONSTRATION OF INNOVATIVE CAPPING TECHNOLOGIES FOR THE RISK MANAGEMENT OF CONTAMINATED SEDIMENTS

    EPA Science Inventory

    Research on capping technologies is directed at assessing the effectiveness of innovative capping materials, factors that control contaminant release at the sediment-water interface, installation of cap, resuspension mechanism, and gas ebullition. U.S. EPA's Land Remediation and ...

  16. Fixing mechanism for a wireline core barrel of core drilling equipment

    SciTech Connect

    Nenkov, N.D.; Petrov, I.B.; Peev, S.P.

    1987-05-12

    This patent describes a wireline mechanism for removing a core barrel containing a core from within a hollow drill string carrying a hollow drill crown cutter on its lower end while the drill string is in position in the earth. The mechanism comprises a cylindrical fixer adapted to be mounted within the drill string coaxially thereof. A cap for attachment to a flexible elongated core-removing member is secured to the upper end of the fixer, a cylindrical hollow body is adapted to be mounted within the drill string coaxially thereof and generally below the fixer. A lower portion of the fixer is adapted to be telescoped within the upper portion of the cylindrical hollow body, a longitudinally extending stopper bar is connected to the upper part of the cylindrical hollow body, a locking bar and a nut connect the fixer to the lower part of the cylindrical hollow body.

  17. The 4 CORE Factors for School Success

    ERIC Educational Resources Information Center

    Whitaker, Todd; Zoul, Jeffrey

    2008-01-01

    This book clarifies the core values which all great educators have in common and contribute to school success. For all those who want to create better schools, these factors are at the center of behaviors which lead to "results". The 4 CORE Factors are Communication, Observation, Relationships, and Expectations.

  18. Fractions, Decimals, and the Common Core

    ERIC Educational Resources Information Center

    Kreith, Kurt

    2014-01-01

    At grade 7, Common Core's content standards call for the use of long division to find the decimal representation of a rational number. With an eye to reconciling this requirement with Common Core's call for "a balanced combination of procedure and understanding," a more transparent form of long division is developed. This leads to the…

  19. Temperature Distribution within a Cold Cap during Nuclear Waste Vitrification.

    PubMed

    Dixon, Derek R; Schweiger, Michael J; Riley, Brian J; Pokorny, Richard; Hrma, Pavel

    2015-07-21

    The kinetics of the feed-to-glass conversion affects the waste vitrification rate in an electric glass melter. The primary area of interest in this conversion process is the cold cap, a layer of reacting feed on top of the molten glass. The work presented here provides an experimental determination of the temperature distribution within the cold cap. Because direct measurement of the temperature field within the cold cap is impracticable, an indirect method was developed in which the textural features in a laboratory-made cold cap with a simulated high-level waste feed were mapped as a function of position using optical microscopy, scanning electron microscopy, energy dispersive spectroscopy, and X-ray diffraction. The temperature distribution within the cold cap was established by correlating microstructures of cold-cap regions with heat-treated feed samples of nearly identical structures at known temperatures. This temperature profile was compared with a mathematically simulated profile generated by a cold-cap model that has been developed to assess the rate of glass production in a melter.

  20. Native Grasses as a Management Alternative on Vegetated Closure Caps

    NASA Astrophysics Data System (ADS)

    Kwit, Charles; Collins, Beverly

    2008-06-01

    Capped waste sites often are vegetated with commercial turf grasses to increase evapotranspiration and prevent erosion and possible exposure of the barrier. Fertilizer, frequent watering, and mowing may be required to establish the turf grass and prevent invasion by trees and shrubs. Oldfield vegetation of grasses and forbs is a possible sustainable alternative to turf grass communities. To determine if oldfield vegetation can establish on caps, we (1) compared establishment of a dominant oldfield grass and a commercial turf grass under different combinations of new closure cap management: spring or summer planting and presence or absence of amendments to alleviate drought (watering, mulch) or increase soil fertility (fertilizer, lime, a nitrogen-fixing legume); (2) surveyed existing caps to determine if oldfield species establish naturally; and (3) performed a greenhouse experiment to compare growth of two native grasses under low and amended (added water, soil nutrients) conditions. Both the commercial grass and oldfield species established under new cap conditions; fertilizer, water, and mulch improved vegetation establishment in spring or summer, but legumes decreased grass cover. In the greenhouse, both native grasses grew best with amendments; however, substantial stem and root length were obtained with no fertilizer and only once-weekly watering. Existing vegetated caps supported planted grasses and naturally established oldfield species. Overall, the results indicate native grasses can establish on new caps and oldfields can serve as a management model; further work is needed to determine the management strategy to maintain herbaceous vegetation and slow woody species invasion.

  1. Conventional and unconventional mechanisms for capping viral mRNA.

    PubMed

    Decroly, Etienne; Ferron, François; Lescar, Julien; Canard, Bruno

    2012-01-01

    In the eukaryotic cell, capping of mRNA 5' ends is an essential structural modification that allows efficient mRNA translation, directs pre-mRNA splicing and mRNA export from the nucleus, limits mRNA degradation by cellular 5'-3' exonucleases and allows recognition of foreign RNAs (including viral transcripts) as 'non-self'. However, viruses have evolved mechanisms to protect their RNA 5' ends with either a covalently attached peptide or a cap moiety (7-methyl-Gppp, in which p is a phosphate group) that is indistinguishable from cellular mRNA cap structures. Viral RNA caps can be stolen from cellular mRNAs or synthesized using either a host- or virus-encoded capping apparatus, and these capping assemblies exhibit a wide diversity in organization, structure and mechanism. Here, we review the strategies used by viruses of eukaryotic cells to produce functional mRNA 5'-caps and escape innate immunity. PMID:22138959

  2. Trafficking of. cap alpha. -L-fucosidase in lymphoid cells

    SciTech Connect

    DiCioccio, R.A.; Brown, K.S.

    1987-05-01

    The quantity of ..cap alpha..-L-fucosidase in human serum is determined by heredity. The mechanism controlling levels of the enzyme in serum is unknown. To investigate this, lymphoid cell lines derived from individuals with either low, intermediate or high ..cap alpha..-L-fucosidase in serum were established. Steady state levels of extracellular ..cap alpha..-L-fucosidase protein and activity overlapped among the cell lines. Thus, in vivo serum phenotypes of ..cap alpha..-L-fucosidase are not adequately expressed in this system. ..cap alpha..-L-Fucosidase was also metabolically labelled with /sup 35/S-methionine, immunoprecipitated, and examined by SDS-PAGE. Cells pulse-labelled from 0.25-2 h had a major intracellular form of enzyme (Mr = 58,000). Cells pulsed for 1.5 h and chased for 21 h with unlabeled methionine had an intracellular form of Mr = 60,000 and an extracellular form of Mr = 62,000. Cells treated with chloroquine had only the 58,000-form both intra- and extra-cellularly. Moreover, chloroquine did not effect the quantitative distribution of ..cap alpha..-L-fucosidase between cells and medium. In fibroblasts, chloroquine enhanced the secretion of newly made lysosomal enzymes and blocked the processing of intercellular enzyme forms from a higher to a lower molecular mass. Thus, there are trafficking differences between ..cap alpha..-L-fucosidase in lymphoid cells and lysosomal enzymes in fibroblasts. This suggests that alternative targeting mechanisms for lysosomal enzymes exist in these cells.

  3. Inner Core Structure Behind the PKP Core Phase Triplication

    NASA Astrophysics Data System (ADS)

    Blom, N.; Paulssen, H.; Deuss, A. F.; Waszek, L.

    2015-12-01

    Despite its small size, the Earth's inner core plays an important role in the Earth's dynamics. Because it is slowly growing, its structure - and the variation thereof with depth - may reveal important clues about the history of the core, its convection and the resulting geodynamo. Learning more about this structure has been a prime effort in the past decades, leading to discoveries about anisotropy, hemispheres and heterogeneity in the inner core in general. In terms of detailed structure, mainly seismic body waves have contributed to these advances. However, at depths between ~100-200 km, the seismic structure is relatively poorly known. This is a result of the PKP core phase triplication and the existence of strong precursors to PKP phases, whose simultaneous arrival hinders the measurement of inner core waves PKIKP at epicentral distances between roughly 143-148°. As a consequence, the interpretation of deeper structure also remains difficult. To overcome these issues, we stack seismograms in slowness and time, separating PKP and PKIKP phases which arrive simultaneously, but with different slowness. We apply this method to study the inner core's Western hemisphere between South and Central America using paths travelling in the quasi-polar direction between epicentral distances of 140-150°. This enables us to measure PKiKP-PKIKP differential travel times up to greater epicentral distance than has previously been done. The resulting differential travel time residuals increase with epicentral distance, indicating a marked increase in seismic velocity with depth compared to reference model AK135 for the studied polar paths. Assuming a homogeneous outer core, these findings can be explained by either (i) inner core heterogeneity due to an increase in isotropic velocity, or (ii) increase in anisotropy over the studied depth range. Our current data set cannot distinguish between the two hypotheses, but in light of previous work we prefer the latter interpretation.

  4. Reducing the recruitment of sedimented algae and nutrient release into the overlying water using modified soil/sand flocculation-capping in eutrophic lakes.

    PubMed

    Pan, Gang; Dai, Lichun; Li, Liang; He, Linchen; Li, Hong; Bi, Lei; Gulati, Ramesh D

    2012-05-01

    The effect of simultaneously removing algal blooms from water and reducing the resuspension and nutrient release from the sediment was studied using modified local soil/sand flocculation-capping (MLS-capping) in simulated water-sediment systems. Twenty one sediment cores in situ with overlying water containing algal blooms were collected from Meiliang Bay of Lake Taihu (China) in July 2011. The algal cells in the water were flocculated and sunk to the sediment using chitosan modified local soils, and the algal flocs were capped with modified and nonmodified soil/sand and then incubated at 25 °C for 20 days. In the MLS-capping treated systems, the TP concentration was reduced from 2.56 mg P L(-1) to 0.06-0.14 mg P L(-1) and TN from 14.66 mg N L(-1) to 6.03-9.56 mg N L(-1) throughout the experiment, whereas the sediment to water fluxes of TP, TN, PO(4)-P, and NH(4)-N were greatly reduced or reversed and the redox potential remarkably increased compared to the control system. A capping layer of 1 cm chitosan-modified sand decreased the resuspension of the sediment by a factor of 5 compared to the clay/soil/sediment systems and the overlying water kept clear even under constant stirring conditions (200 rpm). The study suggested that by using MLS-capping technology it is possible to quickly reduce the nutrient and turbidity of water by flocculating and capping the algal cells into the sediment, where the resuspension of algal flocs is physically reduced and the diffusion of nutrients from sediment to the overlying water chemically blocked by the MLS capping layers.

  5. Influenza A virus preferentially snatches noncoding RNA caps.

    PubMed

    Gu, Weifeng; Gallagher, Glen R; Dai, Weiwei; Liu, Ping; Li, Ruidong; Trombly, Melanie I; Gammon, Don B; Mello, Craig C; Wang, Jennifer P; Finberg, Robert W

    2015-12-01

    Influenza A virus (IAV) lacks the enzyme for adding 5' caps to its RNAs and snatches the 5' ends of host capped RNAs to prime transcription. Neither the preference of the host RNA sequences snatched nor the effect of cap-snatching on host processes is completely defined. Previous studies of influenza cap-snatching used poly(A)-selected RNAs from infected cells or relied on annotated host genes to define the snatched host RNAs, and thus lack details on many noncoding host RNAs including snRNAs, snoRNAs, and promoter-associated capped small (cs)RNAs, which are made by "paused" Pol II during transcription initiation. In this study, we used a nonbiased technique, CapSeq, to identify host and viral-capped RNAs including nonpolyadenylated RNAs in the same samples, and investigated the substrate-product correlation between the host RNAs and the viral RNAs. We demonstrated that noncoding host RNAs, particularly U1 and U2, are the preferred cap-snatching source over mRNAs or pre-mRNAs. We also found that csRNAs are highly snatched by IAV. Because the functions of csRNAs remain mostly unknown, especially in somatic cells, our finding reveals that csRNAs at least play roles in the process of IAV infection. Our findings support a model where nascent RNAs including csRNAs are the preferred targets for cap-snatching by IAV and raise questions about how IAV might use snatching preferences to modulate host-mRNA splicing and transcription.

  6. Simian virus 40 early mRNA's in lytically infected and transformed cells contain six 5'-terminal caps.

    PubMed

    Kahana, C; Gidoni, D; Canaani, D; Groner, Y

    1981-01-01

    Late simian virus 40 (SV40) mRNA contains eight different cap structures which we have previously identified and mapped on the viral genome. As reported here, 5'-cap heterogeneity is a common feature to both the early and the late SV40 mRNA's. methyl-3H-labeled viral mRNA was purified from cells infected at 41 degrees C with SV40 mutant tsA209. Three different cap cores were identified: m7GpppGm, m7GpppCm, and m7GpppAm. An average of three to four m6A residues per mRNA molecule was found. RNase T2-resistant 32P-labeled early caps from tsA209-infected cells isolated and characterized. Six distinct cap I structures were identified: m7GpppCmpU (30%), m7GpppGmpC (24%), m7GpppAmpG (18%), m7GpppGmpU (13%), m7GpppGmpG (12%), and m7GpppAmpU (3%). A similar 5'-end heterogeneity was observed in early SV40 mRNA from BSC-1 cells infected with wild-type SV40 strain 777 in the presence of cytosine arabinoside and in the SV40 UV-transformed permissive line C-6. Five of these capped dinucleotides are complementary to DNA sequences at 0.66 map unit in a region previously identified by the primer extension method (Reddy et al., J. Virol. 30:279-296, 1979; Thompson et al., J. Virol. 31:437-438, 1979) as the 5' end of the early message. DNA sequences upstream from this region contain the TATTTAT (Hogness-Goldberg box), which is missing from upstream of the 5'-cap sites of late SV40 mRNA. Thus, 5'-end heterogeneity is not necessarily related to the presence or the absence of this putative transcriptional "initiation signal." When the possibility that SV40 5' caps represent transcriptional initiation sites is considered, the data also suggest that, on SV40 DNA, eucaryotic RNA polymerase II initiates transcription at multiple nucleotide sequences, including pyrimidines. PMID:6261002

  7. Accumulations of Ca/P in the core of hairs from Taklamakan desert mummies

    NASA Astrophysics Data System (ADS)

    Hallégot, P.; Walter, P.; Cotte, M.; Audinot, J.-N.; Guillot, J.; Migeon, H.-N.; Tallarek, E.; Hagenhoff, B.

    2008-12-01

    Hairs from mummies discovered in the west China Taklamakan desert are investigated by NanoSIMS, ToF-SIMS, Auger and TEM. Intra-medullar accumulations of calcium and phosphorus are described. The present study is an attempt to understand the significance of these accumulations. Their possible exogenous or endogenous origin is debated. Moreover, TEM revealed a particular nature of the accumulation that decorates a fibrilar structure of the medullar. To what extent did molecular control govern the particle growth and does such an accumulation represent a step toward the mineralization of the keratinized fiber?

  8. Oxidation resistance of Ru-capped EUV multilayers

    SciTech Connect

    Bajt, S; Dai, Z; Nelson, E J; Wall, M A; Alameda, J; Nguyen, N; Baker, S; Robinson, J C; Taylor, J S; Clift, M; Aquila, A; Gullikson, E M; Edwards, N G

    2005-02-23

    Differently prepared Ru-capping layers, deposited on Mo/Si EUV multilayers, have been characterized using a suite of metrologies to establish their baseline structural, optical, and surface properties in as-deposited state. Same capping layer structures were tested for their thermal stability and oxidation resistance. Post-mortem characterization identified changes due to accelerated tests. The best performing Ru-capping layer structure was studied in detail with transmission electron microscopy to identify the grain microstructure and texture. This information is essential for modeling and performance optimization of EUVL multilayers.

  9. Space fabrication demonstration system composite beam cap fabricator

    NASA Technical Reports Server (NTRS)

    1982-01-01

    A detailed design for a prototype, composite beam cap fabricator was established. Inputs to this design included functional tests and system operating requirements. All required materials were procured, detail parts were fabricated, and one composite beam cap forming machine was assembled. The machine was demonstrated as a stand-alone system. Two 12-foot-long beam cap members were fabricated from laminates graphite/polysulfane or an equivalent material. One of these members, which as structurally tested in axial compression, failed at 490 pounds.

  10. The hemispherical asymmetry of the residual polar caps on Mars

    NASA Technical Reports Server (NTRS)

    Lindner, Bernhard Lee

    1991-01-01

    A model of the polar caps of Mars was created which allows: (1) for light penetration into the cap; (2) ice albedo to vary with age, latitude, hemisphere, dust content, and solar zenith angle; and (3) for diurnal variability. The model includes the radiative effects of clouds and dust, and heat transport as represented by a thermal wind. The model reproduces polar cap regression data very well, including the survival of CO2 frost at the south pole and reproduces the general trend in the Viking Lander pressure data.

  11. The catheter hub disinfection cap as esophageal foreign body.

    PubMed

    Tawfik, Kareem O; Myer, Charles M; Shikary, Tasneem; Goldschneider, Kenneth R

    2015-12-01

    Disinfection caps are increasingly being used to prevent catheter-associated bloodstream infections. These devices, designed for continuous passive disinfection of catheter hubs, are typically small and often brightly colored. As such, they have the potential to become pediatric airway and esophageal foreign bodies. We report two patients who developed esophageal foreign body following ingestion of disinfection caps. Given the increasing use of these devices, it is imperative that health care providers be aware of this potential iatrogenic problem. We propose that the use of disinfection caps may not be appropriate in pediatric patients with risk factors for foreign body ingestion.

  12. Apparatus and method for cooling a combustor cap

    DOEpatents

    Zuo, Baifang; Washam, Roy Marshall; Wu, Chunyang

    2014-04-29

    A combustor includes an end cap having a perforated downstream plate and a combustion chamber downstream of the downstream plate. A plenum is in fluid communication with the downstream plate and supplies a cooling medium to the combustion chamber through the perforations in the downstream plate. A method for cooling a combustor includes flowing a cooling medium into a combustor end cap and impinging the cooling medium on a downstream plate in the combustor end cap. The method further includes flowing the cooling medium into a combustion chamber through perforations in the downstream plate.

  13. Model for the positional differentiation of the cap in Acetabularia.

    PubMed

    Rommelaere, J; Hiernaux, J

    1975-10-01

    A late stage during the biological cycle of the unicellular alga Acetabularia is the differentiation of a cap at the apical end of the stalk. A minimal model of the spatio-temporal regulation of this event is proposed on the basis of biological data available and current hypotheses. This involves the interaction between a diffusing inhibitor specific to the translation of cap mRNAs and a graded distribution of these messengers. The model accounts for delayed protein synthesis which occurs preferably at the apex and is likely to initiate the formation of the cap. The biological and theoretical implications are discussed.

  14. Biomolecularly capped uniformly sized nanocrystalline materials: glutathione-capped ZnS nanocrystals

    NASA Astrophysics Data System (ADS)

    Torres-Martínez, Claudia L.; Nguyen, Liem; Kho, Richard; Bae, Weon; Bozhilov, Krassimir; Klimov, Victor; Mehra, Rajesh K.

    1999-09-01

    Micro-organisms such as bacteria and yeasts form CdS to detoxify toxic cadmium ions. Frequently, CdS particles formed in yeasts and bacteria were found to be associated with specific biomolecules. It was later determined that these biomolecules were present at the surface of CdS. This coating caused a restriction in the growth of CdS particles and resulted in the formation of nanometre-sized semiconductors (NCs) that exhibited typical quantum confinement properties. Glutathione and related phytochelatin peptides were shown to be the biomolecules that capped CdS nanocrystallites synthesized by yeasts Candida glabrata and Schizosaccharomyces pombe. Although early studies showed the existence of specific biochemical pathways for the synthesis of biomolecularly capped CdS NCs, these NCs could be formed in vitro under appropriate conditions. We have recently shown that cysteine and cysteine-containing peptides such as glutathione and phytochelatins can be used in vitro to dictate the formation of discrete sizes of CdS and ZnS nanocrystals. We have evolved protocols for the synthesis of ZnS or CdS nanocrystals within a narrow size distribution range. These procedures involve three steps: (1) formation of metallo-complexes of cysteine or cysteine-containing peptides, (2) introduction of stoichiometric amounts of inorganic sulfide into the metallo-complexes to initiate the formation of nanocrystallites and finally (3) size-selective precipitation of NCs with ethanol in the presence of Na+. The resulting NCs were characterized by optical spectroscopy, high-resolution transmission electron microscopy (HRTEM), x-ray diffraction and electron diffraction. HRTEM showed that the diameter of the ZnS-glutathione nanocrystals was 3.45+/-0.5 nm. X-ray diffraction and electron diffraction analyses indicated ZnS-glutathione to be hexagonal. Photocatalytic studies suggest that glutathione-capped ZnS nanocrystals prepared by our procedure are highly efficient in degrading a test model

  15. Disease causing mutations in inverted formin 2 regulate its binding to G-actin, F-actin capping protein (CapZ α-1) and profilin 2

    PubMed Central

    Rollason, Ruth; Wherlock, Matthew; Heath, Jenny A.; Heesom, Kate J.; Saleem, Moin A.; Welsh, Gavin I.

    2016-01-01

    Focal segmental glomerulosclerosis (FSGS) is a devastating form of nephrotic syndrome which ultimately leads to end stage renal failure (ESRF). Mutations in inverted formin 2 (INF2), a member of the formin family of actin-regulating proteins, have recently been associated with a familial cause of nephrotic syndrome characterized by FSGS. INF2 is a unique formin that can both polymerize and depolymerize actin filaments. How mutations in INF2 lead to disease is unknown. In the present study, we show that three mutations associated with FSGS, E184K, S186P and R218Q, reduce INF2 auto-inhibition and increase association with monomeric actin. Furthermore using a combination of GFP–INF2 expression in human podocytes and GFP-Trap purification coupled with MS we demonstrate that INF2 interacts with profilin 2 and the F-actin capping protein, CapZ α-1. These interactions are increased by the presence of the disease causing mutations. Since both these proteins are involved in the dynamic turnover and restructuring of the actin cytoskeleton these changes strengthen the evidence that aberrant regulation of actin dynamics underlies the pathogenesis of disease. PMID:26764407

  16. The Non-catalytic “Cap Domain” of a Mycobacterial Metallophosphoesterase Regulates Its Expression and Localization in the Cell*

    PubMed Central

    Matange, Nishad; Podobnik, Marjetka; Visweswariah, Sandhya S.

    2014-01-01

    Despite highly conserved core catalytic domains, members of the metallophosphoesterase (MPE) superfamily perform diverse and crucial functions ranging from nucleotide and nucleic acid metabolism to phospholipid hydrolysis. Unique structural elements outside of the catalytic core called “cap domains” are thought to provide specialization to these enzymes; however, no directed study has been performed to substantiate this. The cap domain of Rv0805, an MPE from Mycobacterium tuberculosis, is located C-terminal to its catalytic domain and is dispensable for the catalytic activity of this enzyme in vitro. We show here that this C-terminal extension (CTE) mediates in vivo localization of the protein to the cell membrane and cell wall as well as modulates expression levels of Rv0805 in mycobacteria. We also demonstrate that Rv0805 interacts with the cell wall of mycobacteria, possibly with the mycolyl-arabinogalactan-peptidoglycan complex, by virtue of its C terminus, a hitherto unknown property of this MPE. Using a panel of mutant proteins, we identify interactions between active site residues of Rv0805 and the CTE that determine its association with the cell wall. Finally, we show that Rv0805 and a truncated mutant devoid of the CTE produce different phenotypic effects when expressed in mycobacteria. Our study thus provides a detailed dissection of the functions of the cap domain of an MPE and suggests that the repertoire of cellular functions of MPEs cannot be understood without exploring the modulatory effects of these subdomains. PMID:24970891

  17. Effect of high-latitude ionospheric convection on Sun-aligned polar caps

    NASA Technical Reports Server (NTRS)

    Sojka, J. J.; Zhu, L.; Crain, D. J.; Schunk, R. W.

    1994-01-01

    A coupled magnetospheric-ionospheric (M-I) magnetohydrodynamic (MHD) model has been used to simulate the formation of Sun-aligned polar cap arcs for a variety of interplanetary magnetic field (IMF) dependent polar cap convection fields. The formation process involves launching an Alfven shear wave from the magnetosphere to the ionosphere where the ionospheric conductance can react self-consistently to changes in the upward currents. We assume that the initial Alfven shear wave is the result of solar wind-magnetosphere interactions. The simulations show how the E region density is affected by the changes in the electron precipitation that are associated with the upward currents. These changes in conductance lead to both a modified Alfven wave reflection at the ionosphere and the generation of secondary Alfven waves in the ionosphere. The ensuing bouncing of the Alfven waves between the ionosphere and magnetosphere is followed until an asymptotic solution is obtained. At the magnetosphere the Alfven waves reflect at a fixed boundary. The coupled M-I Sun-aligned polar cap arc model of Zhu et al.(1993a) is used to carry out the simulations. This study focuses on the dependence of the polar cap arc formation on the background (global) convection pattern. Since the polar cap arcs occur for northward and strong B(sub y) IMF conditions, a variety of background convection patterns can exist when the arcs are present. The study shows that polar cap arcs can be formed for all these convection patterns; however, the arc features are dramatically different for the different patterns. For weak sunward convection a relatively confined single pair of current sheets is associated with the imposed Alfven shear wave structure. However, when the electric field exceeds a threshold, the arc structure intensifies, and the conductance increases as does the local Joule heating rate. These increases are faster than a linear dependence on the background electric field strength. Furthermore

  18. Core-core and core-valence correlation

    NASA Technical Reports Server (NTRS)

    Bauschlicher, Charles W., Jr.; Langhoff, Stephen R.; Taylor, Peter R.

    1988-01-01

    The effect of (1s) core correlation on properties and energy separations was analyzed using full configuration-interaction (FCI) calculations. The Be 1 S - 1 P, the C 3 P - 5 S and CH+ 1 Sigma + or - 1 Pi separations, and CH+ spectroscopic constants, dipole moment and 1 Sigma + - 1 Pi transition dipole moment were studied. The results of the FCI calculations are compared to those obtained using approximate methods. In addition, the generation of atomic natural orbital (ANO) basis sets, as a method for contracting a primitive basis set for both valence and core correlation, is discussed. When both core-core and core-valence correlation are included in the calculation, no suitable truncated CI approach consistently reproduces the FCI, and contraction of the basis set is very difficult. If the (nearly constant) core-core correlation is eliminated, and only the core-valence correlation is included, CASSCF/MRCI approached reproduce the FCI results and basis set contraction is significantly easier.

  19. Surface exposure dating of Little Ice Age ice cap advances on Disko Island, West Greenland

    NASA Astrophysics Data System (ADS)

    Lane, Timothy; Jomelli, Vincent; Rinterknecht, Vincent; Brunstein, Daniel; Schimmelpfennig, Irene; Swingedouw, Didier; Favier, Vincent; Masson-Delmotte, Valerie

    2015-04-01

    Little Ice Age (LIA: 1200-1920 AD) glacier advances in Greenland often form the most extensive positions of Greenland Ice Sheet (GrIS) ice cap and margins since the Early Holocene. Across Greenland these advances are commonly represented by un-vegetated moraines, usually within 1-5 km of the present ice margin. However, chronological constraints on glacier advances during this period are sparse, meaning that GrIS and ice cap behavior and advance/retreat chronology remains poorly understood during this period. At present the majority of ages are based on historical accounts, ice core data, and radiocarbon ages from proglacial threshold lakes. However, developments in the accuracy and precision of surface exposure methods allow dating of LIA moraine boulders, permitting an opportunity to better understand of ice dynamics during this period. Geomorphological mapping and surface exposure dating (36Cl) were used to interpret moraine deposits from the Lyngmarksbræen on Disko Island, West Greenland. A Positive Degree Day (PDD) model was used to estimate Equilibrium Line Altitude (ELA) and mass balance changes for two distinct paleo-glacial extents. Three moraines (M1, M2, and M3) were mapped in the field, and sampled for 36Cl surface exposure dating. The outermost moraine (M1) was of clearly different morphology to the inner moraines, and present only in small fragments. M2 and M3 were distinct arcuate termino-lateral moraines within 50 m of one another, 1.5 km from the present ice margin. The weighted average of four 36Cl ages from M1 returned an early Holocene age of 8.4 ± 0.6 ka. M2 (four samples) returned an age of 0.57 ± 0.04 ka (1441 AD) and M3 (four samples) returned an age of 0.28 ± 0.02 ka (1732 AD). These surface exposure ages represent the first robustly dated Greenlandic ice cap moraine sequence from the LIA. The two periods of ice cap advance and marginal stabilisation are similar to recorded periods of LIA GrIS advance in west Greenland, constrained

  20. Optical properties of P3HT:tributylphosphine oxide-capped CdSe nanocomposites

    NASA Astrophysics Data System (ADS)

    Benchaabane, A.; Ben Hamed, Z.; Lahmar, A.; Sanhoury, M. A.; Kouki, F.; Zellama, K.; Zeinert, A.; Bouchriha, H.

    2016-08-01

    The optical properties of nanocomposite layers prepared by incorporation of tributylphosphine oxide (TBPO)-capped CdSe nanocrystals (NCs) in a P3HT polymer matrix are studied using different nanocrystal concentrations. Reflection spectra analyzed through Kim oscillator model lead to the determination of optical constants such as refractive index n, extinction coefficient k, dielectric permittivity ɛ and absorption coefficient α.Using the common Cauchy, Drude-Lorentz, Tauc and single-effective-oscillator theoretical models, we have determined the values of static refractive index n s and permittivity ɛ s, plasma frequency ω_{{p}}, carrier density N, optical band gap E g and oscillator and dispersion energies E0 and E d, respectively. It is found that TBPO-capped CdSe NCs concentration affects the optoelectronic parameters of the nanocomposite thin films. Moreover, the disorder of this hybrid system is also studied by the determination of Urbach energy, which increases with TBPO-capped CdSe concentration.

  1. The RECAP ice core - recovering a full Glacial record from Eastern Greenland

    NASA Astrophysics Data System (ADS)

    Vinther, Bo

    2016-04-01

    During May-June 2015 the 584m an international team drilled the RECAP (REnland ice CAp Project) ice core to bedrock on the Renland ice cap in Eastern Greenland. The exact drill site selection was determined from a detailed radio echo sounding (RES) grid, that had been measured from the ice cap surface right before drilling operations began. The RES data suggested that the ice cap internal layers are horizontal almost right down to the bed at the selected site, and that ice from the Glacial period was present some 30-50m above bedrock. The RES results have now been confirmed by measurements on the RECAP core that shows the entire Glacial being nicely preserved in the 20m section indicated by the RES measurements. The RECAP core thus yields the first undisturbed ice core record from Eastern Greenland covering the last Glacial, a marked improvement compared to the landmark 1988 Renland ice core that was disturbed by ice flow features both during the mid-Holocene and especially during Marine Isotope Stages 4 and 5.

  2. Idealized model of polar cap currents, fields, and auroras

    NASA Technical Reports Server (NTRS)

    Cornwall, J. M.

    1985-01-01

    During periods of northward Bz, the electric field applied to the magnetosphere is generally opposite to that occurring during southward Bz and complicated patterns of convection result, showing some features reversed in comparison with the southward Bz case. A study is conducted of a simple generalization of early work on idealized convection models, which allows for coexistence of sunward convection over the central polar cap and antisunward convection elsewhere in the cap. The present model, valid for By approximately 0, has a four-cell convection pattern and is based on the combination of ionospheric current conservation with a relation between parallel auroral currents and parallel potential drops. Global magnetospheric issues involving, e.g., reconnection are not considered. The central result of this paper is an expression giving the parallel potential drop for polar cap auroras (with By approximately 0) in terms of the polar cap convection field profile.

  3. Fluctuant magnetism in metal oxide nanocrystals capped with surfactants

    NASA Astrophysics Data System (ADS)

    Zhang, Jianhui; Xiong, Shijie; Wu, Xinglong; Thurber, Aaron; Jones, Michael; Gu, Min; Pan, Zhongda; Tenne, Dmitri A.; Hanna, Charles B.; Du, Youwei; Punnoose, Alex

    2013-08-01

    We demonstrate experimentally that magnetism in ZnO, TiO2, CeO2, and SnO2 nanocrystals (NCs) has a fluctuant nature that varies with capping surfactant type and concentration. By developing a forced hydrolysis approach with additional postprocessing for the synthesis and surfactant capping of these NCs, we effectively avoid the influence of size, shape, and magnetic impurities on the magnetic behavior of NCs, thus revealing the systematic influence of the capping surfactants on the NC magnetism. The x-ray photoelectron spectroscopy results and theoretical calculations clearly show that the magnetism fluctuation with surfactant concentration can be attributed to the periodic variation of spins, which arises from the concentration-dependent electron transfer from surfactants to NCs. Our results not only explain the previously reported seemingly irregular magnetism induced by capping surfactants but also provide an effective approach to tune or optimize the NC magnetism.

  4. Mechanical capping of silica nanotubes for encapsulation of molecules.

    PubMed

    Yu, Jaeeun; Bai, Xia; Suh, Junghun; Lee, Sang Bok; Son, Sang Jun

    2009-11-01

    Multifunctional silica nanotubes (SNTs) are being widely used for many biomedical applications due to their structural benefits. Controlling the structure of the open end of an SNT is a crucial step for drug/gene delivery and for fabrication of multifunctional SNTs. We developed a mechanical capsulation method to fabricate caps at the ends of SNTs. A thin layer of malleable capping materials (Au, Ag, PLGA) was deposited onto the surface of an SNT-grown AAO template. Capped SNTs were then obtained by hammering with alumina microbeads. For a proof-of-concept experiment, we demonstrated dye-encapsulated SNTs without any chemical functionalizations. Since a mechanical approach is free of the issue of chemical compatibility between cargo molecules and capping materials, the method can provide an effective platform for the preparation of smart multifunctional nanotubes for biomedical applications. PMID:19824675

  5. Wind blade spar cap and method of making

    DOEpatents

    Mohamed, Mansour H.

    2008-05-27

    A wind blade spar cap for strengthening a wind blade including an integral, unitary three-dimensional woven material having a first end and a second end, corresponding to a root end of the blade and a tip end of the blade, wherein the material tapers in width from the first to the second end while maintaining a constant thickness and decreasing weight therebetween, the cap being capable of being affixed to the blade for providing increased strength with controlled variation in weight from the root end to the tip end based upon the tapered width of the material thereof. The present inventions also include the method of making the wind blade spar cap and a wind blade including the wind blade spar cap.

  6. 6. Detail of pilaster cap. Aug. 10, 1936. Joseph Hill, ...

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

    6. Detail of pilaster cap. Aug. 10, 1936. Joseph Hill, photographer, copied from small photo taken by survey member. - Jansonist Colony, Steeple Building, Main & Bishop Hill Streets, Bishop Hill, Henry County, IL

  7. 10. Substructure of bridge, showing timber bents, piles, crossbracing, caps ...

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

    10. Substructure of bridge, showing timber bents, piles, cross-bracing, caps and stringers under deck. View to northeast. - Outlet Creek Bridge, Sullivan Lake Ranger Administrative Site, Metaline Falls, Pend Oreille County, WA

  8. Fast-flowing outlet glaciers on Svalbard ice caps

    SciTech Connect

    Dowdeswell, J.A. ); Collin, R.L. )

    1990-08-01

    Four well-defined outlet glaciers are present on the 2510 km{sup 2} cap of Vestfonna in Nordaustlandet, Svalbard. Airborne radio echo sounding and aerial-photograph and satellite-image analysis methods are used to analyze the morphology and dynamics of the ice cap and its component outlet glaciers. The heavily crevassed outlets form linear depressions in the ice-cap surface and flow an order of magnitude faster than the ridges of uncrevassed ice between them. Ice flow on the ridges is accounted for by internal deformation alone, whereas rates of outlet glacier flow require basal motion. One outlet has recently switched into and out of a faster mode of flow. Rapid terminal advance, a change from longitudinal compression to tension, and thinning in the upper basin indicate surge behavior. Observed outlet glacier discharge is significantly greater than current inputs of mass of the ice cap, indicating that present rates of flow cannot be sustained under the contemporary climate.

  9. 16. PIER CAP DETAIL, SHOWING EXPANSION AND FIXED BEARING SHOES, ...

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

    16. PIER CAP DETAIL, SHOWING EXPANSION AND FIXED BEARING SHOES, BOTTOM CHORD / END POST CONNECTION AND CANTILEVERED SIDEWALK. VIEW TO WEST. - Holbrook Bridge, Spanning Little Colorado River at AZ 77, Holbrook, Navajo County, AZ

  10. Cervical Caps or Diaphragms: Answering Your Patients' Questions

    PubMed Central

    Donlevy, Mary J.

    1987-01-01

    Cervical caps and diaphragms offer a plausible contraceptive alternative for some women. Selection of patients, advantages, disadvantages, and fitting techniques are discussed in order to help answer those difficult patient questions. ImagesFigure 1 PMID:21263962

  11. 11. TIMBER COLUMN AND CAST IRON COLUMN CAP IN FIFTH ...

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

    11. TIMBER COLUMN AND CAST IRON COLUMN CAP IN FIFTH FLOOR WAREHOUSE SPACE. VIEW TO SOUTHWEST. - Commercial & Industrial Buildings, Becker-Hazelton Company Warehouse, 280 Iowa Street, Dubuque, Dubuque County, IA

  12. Extreme Poynting Flux Depostion in the Polar Cap and Polar Cap Boundary Regions During Northward IMF

    NASA Astrophysics Data System (ADS)

    Knipp, D.; Kilcommons, L. M.; Cook, M. R.; Larson, T.; Redmon, R. J.

    2015-12-01

    We investigate several intervals of prolonged northward Interplanetary Magnetic Field (IMF) and describe the correlation between strong Poynting flux and the transverse components of the IMF. We primarily focus on Summer events in each hemisphere when the polar regions are sunlit. During northward IMF the magnetic reconnection regions can form tailward of the magnetic cusp. Using data from the Defense Meteorological Satellite Program (DMSP) F13, F15 and F16 spacecraft we looked for and found areas of strong Poynting flux over the magnetic polar cap regions. Values ranging from 20 mW/m^2 to 140 mW/m^2 were measured in narrow channels, showing that there can be significant energy transport to small concentrated regions at very high latitudes. An example of an event from 2001 is shown in the attached image. We also show where these events occur with respect to the dynamic polar cap boundary and discuss the implications of this extreme Poynting flux for other aspects of polar thermodynamics and electrodynamics.

  13. Recent Advances in Pulp Capping Materials: An Overview

    PubMed Central

    Qureshi, Asma; E., Soujanya; Nandakumar; Pratapkumar; Sambashivarao

    2014-01-01

    Emphasis has shifted from the “doomed” organ concept of an exposed pulp to one of hope and recovery. The era of vital-pulp therapy has been greatly enhanced with the introduction of various pulp capping materials. The aim of this article is to summarize and discuss about the various and newer pulp capping materials used for protection of the dentin-pulp complex. PMID:24596805

  14. Molecular-Weight-Controlled, End-Capped Polybenzimidazoles

    NASA Technical Reports Server (NTRS)

    Connell, John W.; Hergenrother, Paul M.; Smith, Joseph G., Jr.

    1993-01-01

    Novel molecular-weight-controlled end-capped poly(arylene ether benzimidazole)s (PAEBI's) prepared by nucleophilic displacement reaction of di(hydroxyl)benzimidazole monomers with activated aromatic dihalides. Polymers prepared at various molecular weights by upsetting stoichiometry of monomers and end-capped with monohydroxybenzimidazole. Exhibit favorable physical and mechanical properties, improved solubility in polar aprotic solvents and better compression moldability. Potential applications as adhesives, coatings, films, fibers, membranes, moldings, and composite matrix resins.

  15. Capping blowouts from Iran's eight-year war

    SciTech Connect

    Sayers, B. )

    1991-05-01

    This paper reports on capping blowouts from Iran's eight year war. Fires in three Iranian wells (two oil, one gas), started during 1987 by Iraqi sabotage, finally were extinguished during the last several months of 1990. Burning during the final months of the countries' eight-year war, plus another subsequent peaceful two years, the fires consumed millions of barrels of oil and billions of cubic feet of gas before they were capped. Ironically, bringing the wells under control took relatively little time.

  16. RNA methyltransferases involved in 5′ cap biosynthesis

    PubMed Central

    Byszewska, Magdalena; Śmietański, Mirosław; Purta, Elżbieta; Bujnicki, Janusz M

    2014-01-01

    In eukaryotes and viruses that infect them, the 5′ end of mRNA molecules, and also many other functionally important RNAs, are modified to form a so-called cap structure that is important for interactions of these RNAs with many nuclear and cytoplasmic proteins. The RNA cap has multiple roles in gene expression, including enhancement of RNA stability, splicing, nucleocytoplasmic transport, and translation initiation. Apart from guanosine addition to the 5′ end in the most typical cap structure common to transcripts produced by RNA polymerase II (in particular mRNA), essentially all cap modifications are due to methylation. The complexity of the cap structure and its formation can range from just a single methylation of the unprocessed 5′ end of the primary transcript, as in mammalian U6 and 7SK, mouse B2, and plant U3 RNAs, to an elaborate m7Gpppm6,6AmpAmpCmpm3Um structure at the 5′ end of processed RNA in trypanosomes, which are formed by as many as 8 methylation reactions. While all enzymes responsible for methylation of the cap structure characterized to date were found to belong to the same evolutionarily related and structurally similar Rossmann Fold Methyltransferase superfamily, that uses the same methyl group donor, S-adenosylmethionine; the enzymes also exhibit interesting differences that are responsible for their distinct functions. This review focuses on the evolutionary classification of enzymes responsible for cap methylation in RNA, with a focus on the sequence relationships and structural similarities and dissimilarities that provide the basis for understanding the mechanism of biosynthesis of different caps in cellular and viral RNAs. Particular attention is paid to the similarities and differences between methyltransferases from human cells and from human pathogens that may be helpful in the development of antiviral and antiparasitic drugs. PMID:25626080

  17. Density functional study of condensation in capped capillaries.

    PubMed

    Yatsyshin, P; Savva, N; Kalliadasis, S

    2015-07-15

    We study liquid adsorption in narrow rectangular capped capillaries formed by capping two parallel planar walls (a slit pore) with a third wall orthogonal to the two planar walls. The most important transition in confined fluids is arguably condensation, where the pore becomes filled with the liquid phase which is metastable in the bulk. Depending on the temperature T, the condensation in capped capillaries can be first-order (at T≤Tcw) or continuous (at T>Tcw), where Tcw is the capillary wetting temperature. At T>Tcw, the capping wall can adsorb mesoscopic amounts of metastable under-condensed liquid. The onset of condensation is then manifested by the continuous unbinding of the interface between the liquid adsorbed on the capping wall and the gas filling the rest of the capillary volume. In wide capped capillaries there may be a remnant of wedge filling transition, which is manifested by the adsorption of liquid drops in the corners. Our classical statistical mechanical treatment predicts a possibility of three-phase coexistence between gas, corner drops and liquid slabs adsorbed on the capping wall. In sufficiently wide capillaries we find that thick prewetting films of finite length may be nucleated at the capping wall below the boundary of the prewetting transition. Prewetting then proceeds in a continuous manner manifested by the unbinding interface between the thick and thin films adsorbed on the side walls. Our analysis is based on a detailed numerical investigation of the density functional theory for the fluid equilibria for a number of illustrative case studies.

  18. Protein and carotenoid synthesis and turnover in gravistimulated root caps

    NASA Technical Reports Server (NTRS)

    Feldman, L. J.

    1984-01-01

    In certain cultivars of corn gravitropic bending occurs only after the root cap, the site of gravity perception, is exposed to light. Light appears to trigger or to remove some block in the gravity translation process. Using light sensitive cultivars of corn, it was shown that light affects various processes in the cap. The roles of these light-induced processes in gravitropic bending in roots were studied.

  19. Novel Multipin Electrode Cap System for Dry Electroencephalography.

    PubMed

    Fiedler, P; Pedrosa, P; Griebel, S; Fonseca, C; Vaz, F; Supriyanto, E; Zanow, F; Haueisen, J

    2015-09-01

    Current usage of electroencephalography (EEG) is limited to laboratory environments. Self-application of a multichannel wet EEG caps is practically impossible, since the application of state-of-the-art wet EEG sensors requires trained laboratory staff. We propose a novel EEG cap system with multipin dry electrodes overcoming this problem. We describe the design of a novel 24-pin dry electrode made from polyurethane and coated with Ag/AgCl. A textile cap system holds 97 of these dry electrodes. An EEG study with 20 volunteers compares the 97-channel dry EEG cap with a conventional 128-channel wet EEG cap for resting state EEG, alpha activity, eye blink artifacts and checkerboard pattern reversal visual evoked potentials. All volunteers report a good cap fit and good wearing comfort. Average impedances are below 150 kΩ for 92 out of 97 dry electrodes, enabling recording with standard EEG amplifiers. No significant differences are observed between wet and dry power spectral densities for all EEG bands. No significant differences are observed between the wet and dry global field power time courses of visual evoked potentials. The 2D interpolated topographic maps show significant differences of 3.52 and 0.44% of the map areas for the N75 and N145 VEP components, respectively. For the P100 component, no significant differences are observed. Dry multipin electrodes integrated in a textile EEG cap overcome the principle limitations of wet electrodes, allow rapid application of EEG multichannel caps by non-trained persons, and thus enable new fields of application for multichannel EEG acquisition.

  20. Effect of Swim Cap Surface Roughness on Passive Drag.

    PubMed

    Gatta, Giorgio; Cortesi, Matteo; Zamparo, Paola

    2015-11-01

    In the last decade, great attention has been given to the improvements in swimming performance that can be obtained by wearing "technical swimsuits"; the technological evolution of these materials only marginally involved swim caps production, even if several studies have pointed out the important role of the head (as main impact point with the fluid) on hydrodynamics. The aim of this study was to compare the effects on passive drag (Dp) of 3 swim cap models: a smooth silicon helmet cap (usually used during swimming competitions), a silicon helmet cap with "dimples," and a silicon helmet cap with "wrinkles." Experiments were performed on 10 swimmers who were towed underwater (at a depth of 60 cm) at 3 speeds (1.5, 1.7, and 1.9 m·s) and in 2 body positions: LA (arms above the swimmer's head) and SA (arms alongside the body). The Dp values obtained in each trial were divided by the square of the corresponding speed to obtain the speed-specific drag (the k coefficient = Dp/v). No differences in k were observed among swim caps in the LA position. No differences in k were observed between the smooth and dimpled helmets also in the SA position; however, the wrinkled swim cap helmet showed a significant larger k (4.4%) in comparison with the model with dimples, when the swimmers kept their arms alongside the body (in the SA position). These data suggest that wearing a wrinkled swim cap helmet can be detrimental to performance at least in this specific position.

  1. Behavior of pile group with elevated cap subjected to cyclic lateral loads

    NASA Astrophysics Data System (ADS)

    Chen, Yun-min; Gu, Ming; Chen, Ren-peng; Kong, Ling-gang; Zhang, Zhe-hang; Bian, Xue-cheng

    2015-06-01

    The pile group with elevated cap is widely used as foundation of offshore structures such as turbines, power transmission towers and bridge piers, and understanding its behavior under cyclic lateral loads induced by waves, tide water and winds, is of great importance to designing. A large-scale model test on 3×3 pile group with elevated cap subjected to cyclic lateral loads was performed in saturated silts. The preparation and implementation of the test is presented. Steel pipes with the outer diameter of 114 mm, thickness of 4.5 mm, and length of 6 m were employed as model piles. The pile group was cyclic loaded in a multi-stage sequence with the lateral displacement controlled. In addition, a single pile test was also conducted at the same site for comparison. The displacement of the pile cap, the internal forces of individual piles, and the horizontal stiffness of the pile group are presented and discussed in detail. The results indicate that the lateral cyclic loads have a greater impact on pile group than that on a single pile, and give rise to the significant plastic strain in the soil around piles. The lateral loads carried by each row of piles within the group would be redistributed with loading cycles. The lateral stiffness of the pile group decreases gradually with cycles and broadly presents three different degradation patterns in the test. Significant axial forces were measured out in some piles within the group, owing to the strong restraint provided by the cap, and finally lead to a large settlement of the pile group. These findings can be referred for foundation designing of offshore structures.

  2. Comparison of auroral latitude convection to central polar cap convection. (Invited)

    NASA Astrophysics Data System (ADS)

    Bristow, W. A.; Amata, E.

    2013-12-01

    The SuperDARN radar at McMurdo station has been providing convection observations in the central polar cap since January 2010. The Antarctic magnetic pole lies in the center of the radar field of view at about 1000 km range, which is optimum for convection observations. A new pair of SuperDARN radars was constructed in the Antarctic summer of 2012/2013, which add highly complimentary fields of view. The radars, one located at the Italian station at Dome-C, and one located at the US South Pole Station, are directed into a region directly equatorward of the McMurdo field of view. The radars came on line in late January 2013 and are producing excellent convection observations. This paper presents initial results combining the three radar's convection observations. Intervals when the IMF clock angle was between 135 and 225 for periods of more than an hour were selected for study. Just under 50 hours of observations met this criteria since the radars began operation. Convection vectors were formed using the standard SuperDARN algorithm [Ruohoniemi and Baker, 1998] and the auroral-zone flows were compared to those in the central polar cap. Central polar cap flows are typically spatially uniform though highly variable in time, even though the lower latitude observations were spatially structured. The central polar cap average flow velocity is less than 500 m/s, though it often exceeds 1000 m/s. Conditions that lead to the high-speed flow are presented. In addition, correlation with the IMF and solar wind are presented. At times the correlation exceeds 80% while at others it is near zero.

  3. Active capping technology: a new environmental remediation of contaminated sediment.

    PubMed

    Zhang, Chang; Zhu, Meng-Ying; Zeng, Guang-Ming; Yu, Zhi-Gang; Cui, Fang; Yang, Zhong-Zhu; Shen, Liu-Qing

    2016-03-01

    The management and treatment of contaminated sediment is a worldwide problem and poses major technical and economic challenges. Nowadays, various attempts have been committed to investigating a cost-effective way in contaminated sediment restoration. Among the remediation options, in situ capping turns out to be a less expensive, less disruptive, and more durable approach. However, by using the low adsorption capacity materials, traditional caps do not always fulfill the reduction of risks that can be destructive for human health, ecosystem, and even natural resources. Active caps, therefore, are designed to employ active materials (activated carbon, apatite, zeolite, organoclay, etc.) to strengthen their adsorption and degradation capacity. The active capping technology promises to be a permanent and cost-efficient solution to contaminated sediments. This paper provides a review on the types of active materials and the ways of these active materials employed in recent active capping studies. Cap design considerations including site-specific conditions, diffusion/advection, erosive forces, and active material selection that should be noticed in an eligible remediation project are also presented. PMID:26762937

  4. Response of northern winter polar cap to auroral substorms

    NASA Astrophysics Data System (ADS)

    Liou, Kan; Sotirelis, Thomas

    2016-05-01

    The three-phase substorm sequence has been generally accepted and is often tied to the Dungey cycle. Although previous studies have mostly agreed on the increase and decrease in the polar cap area during an episode of substorm, there are disparate views on when the polar cap starts to contract relative to substorm onset. Here we address this conflict using high-resolution (~1-3 min) snapshot global auroral images from the ultraviolet imager on board the Polar spacecraft. On the basis of 28 auroral substorm events, all observed in the Northern Hemispheric winter, it is found that the polar cap inflated prior to onset in all events and it attained the largest area ~6 min prior to the substorm expansion phase onset, while the dayside polar cap area remained steady around the onset. The onset of nightside polar cap deflation is found to be attributed to intensifications of aurora on the poleward edge of the nightside oval, mostly in the midnight sector. Although this result supports the loading-unloading and reconnection substorm models, it is not clear if the initial polar cap deflation and the substorm expansion are parts of the same process.

  5. In vitro antibacterial activity of different pulp capping materials

    PubMed Central

    Beltrami, Riccardo; Colombo, Marco; Ceci, Matteo; Dagna, Alberto; Chiesa, Marco

    2015-01-01

    Background Direct pulp capping involves the application of a dental material to seal communications between the exposed pulp and the oral cavity (mechanical and carious pulp exposures) in an attempt to act as a barrier, protect the dental pulp complex and preserve its vitality. The aim of this study was to evaluate and compare, by the agar disc diffusion test, the antimicrobial activity of six different pulp-capping materials: Dycal (Dentsply), Calcicur (Voco), Calcimol LC (Voco), TheraCal LC (Bisco), MTA Angelus (Angelus), Biodentine (Septodont). Material and Methods Streptococcus salivarius, Streptococcus sanguis and Streptococcus mutans strains were selected to evaluate the antimicrobial activity by the agar disc diffusion test of different pulp capping materials. Paper disks were impregnated whit each pulp capping materials and placed onto culture agar-plates pre-adsorbed with bacterial cells and further incubated for 24 h at 37°C. The growth inhibition zones around each pulp capping materials were recorded and compared for each bacterial strain. Results For the investigation of the antibacterial properties the ANOVA showed the presence of significant differences among the various materials. Tukey test showed that MTA-based materials induced lower growth inhibition zones. Conclusions MTA-based products show a discrete antibacterial activity varying from calcium hydroxide-based materials which present an higher antibacterial activity. Key words:Agar disc diffusion test, antimicrobial activity, calcium hydroxide, MTA, pulp capping materials. PMID:26644833

  6. Systematics of. cap alpha. decay of even--even isotones

    SciTech Connect

    Poplavskii-breve, I.V.

    1987-02-01

    On the basis of an analysis of experimental data we have investigated for the first time the ..cap alpha.. decay of even--even isotones. We have established that the ..cap alpha..-decay energy of isotones depends on the number of protons approximately according to a linear law. We have shown that the Geiger--Nuttall law is valid both for isotopes and isobars, and also for isotones. The deviations from the Geiger--Nuttall law are due to the shell structure of the nucleus. The regularities observed in the ..cap alpha.. decay of isotones have been used to estimate the magnitudes of the ..cap alpha..-decay energies, the kinetic energies of the emitted ..cap alpha.. particles, and the partial half-lives for ..cap alpha.. decay of the known and unknown neutron--deficient nuclei /sup 202//sup ,//sup 204/Ra, /sup 210/Th, /sup 228//sup ,//sup 230/Pu, /sup 234//sup ,//sup 236/Cm, /sup 242//sup ,//sup 244/Fm, /sup 250//sup ,//sup 258/No, and /sup 254//sup ,//sup 256/Ku.

  7. A decision tool for selecting trench cap designs

    SciTech Connect

    Paige, G.B.; Stone, J.J.; Lane, L.J.

    1995-12-31

    A computer based prototype decision support system (PDSS) is being developed to assist the risk manager in selecting an appropriate trench cap design for waste disposal sites. The selection of the {open_quote}best{close_quote} design among feasible alternatives requires consideration of multiple and often conflicting objectives. The methodology used in the selection process consists of: selecting and parameterizing decision variables using data, simulation models, or expert opinion; selecting feasible trench cap design alternatives; ordering the decision variables and ranking the design alternatives. The decision model is based on multi-objective decision theory and uses a unique approach to order the decision variables and rank the design alternatives. Trench cap designs are evaluated based on federal regulations, hydrologic performance, cover stability and cost. Four trench cap designs, which were monitored for a four year period at Hill Air Force Base in Utah, are used to demonstrate the application of the PDSS and evaluate the results of the decision model. The results of the PDSS, using both data and simulations, illustrate the relative advantages of each of the cap designs and which cap is the {open_quotes}best{close_quotes} alternative for a given set of criteria and a particular importance order of those decision criteria.

  8. Cap homeostasis is independent of poly(A) tail length

    PubMed Central

    Kiss, Daniel L.; Oman, Kenji M.; Dougherty, Julie A.; Mukherjee, Chandrama; Bundschuh, Ralf; Schoenberg, Daniel R.

    2016-01-01

    Cap homeostasis is a cyclical process of decapping and recapping that maintains the cap on a subset of the cytoplasmic transcriptome. Interfering with cytoplasmic capping results in the redistribution of target transcripts from polysomes to non-translating mRNPs, where they accumulate in an uncapped but nonetheless stable form. It is generally thought that decapping is preceded by shortening of the poly(A) tail to a length that can no longer support translation. Therefore recapped target transcripts would either have to undergo cytoplasmic polyadenylation or retain a reasonably long poly(A) tail if they are to return to the translating pool. In cells that are inhibited for cytoplasmic capping there is no change in the overall distribution of poly(A) lengths or in the elution profile of oligo(dT)-bound targets. Poly(A) tail lengths were similar for target mRNAs on polysomes or in non-translating mRNPs, and the presence of polyadenylated uncapped mRNA in mRNPs was confirmed by separation into capped and uncapped pools prior to assay. Finally, in silico analysis of cytoplasmic capping targets revealed significant correlations with genes encoding transcripts with uridylated or multiply modified 3′ ends, and genes possessing multiple 3′-untranslated regions (UTRs) generated by alternative cleavage and polyadenylation. PMID:26673707

  9. Neoproterozoic cap-dolostone deposition in stratified glacial meltwater plume

    NASA Astrophysics Data System (ADS)

    Liu, Chao; Wang, Zhengrong; Raub, Timothy D.; Macdonald, Francis A.; Evans, David A. D.

    2014-10-01

    Neoproterozoic cap carbonates host distinctive geochemical and sedimentological features that reflect prevailing conditions in the aftermath of Snowball Earth. Interpretation of these features has remained contentious, with hypotheses hinging upon timescale and synchronicity of deposition, and whether or not geochemical signatures of cap carbonates represent those of a well-mixed ocean. Here we present new high-resolution Sr and Mg isotope results from basal Ediacaran cap dolostones in South Australia and Mongolia. Least-altered Sr and Mg isotope compositions of carbonates are identified through a novel incremental leaching technique that monitors the purity of a carbonate sample and the effects of diagenesis. These data can be explained by the formation of these cap dolostones involving two chemically distinct solutions, a glacial meltwater plume enriched in radiogenic Sr, and a saline ocean residue with relatively lower 87Sr/86Sr ratios. Model simulations suggest that these water bodies remained dynamically stratified during part of cap-dolostone deposition, most likely lasting for ∼8 thousand years. Our results can potentially reconcile previous conflicts between timescales estimated from physical mixing models and paleomagnetic constraints. Geochemical data from cap carbonates used to interpret the nature of Snowball Earth and its aftermath should be recast in terms of a chemically distinct meltwater plume.

  10. Active capping technology: a new environmental remediation of contaminated sediment.

    PubMed

    Zhang, Chang; Zhu, Meng-Ying; Zeng, Guang-Ming; Yu, Zhi-Gang; Cui, Fang; Yang, Zhong-Zhu; Shen, Liu-Qing

    2016-03-01

    The management and treatment of contaminated sediment is a worldwide problem and poses major technical and economic challenges. Nowadays, various attempts have been committed to investigating a cost-effective way in contaminated sediment restoration. Among the remediation options, in situ capping turns out to be a less expensive, less disruptive, and more durable approach. However, by using the low adsorption capacity materials, traditional caps do not always fulfill the reduction of risks that can be destructive for human health, ecosystem, and even natural resources. Active caps, therefore, are designed to employ active materials (activated carbon, apatite, zeolite, organoclay, etc.) to strengthen their adsorption and degradation capacity. The active capping technology promises to be a permanent and cost-efficient solution to contaminated sediments. This paper provides a review on the types of active materials and the ways of these active materials employed in recent active capping studies. Cap design considerations including site-specific conditions, diffusion/advection, erosive forces, and active material selection that should be noticed in an eligible remediation project are also presented.

  11. Effects of Atmospheric Dust on Residual South Polar Cap Stability

    NASA Technical Reports Server (NTRS)

    Bonrv, B. P.; Bjorkman, J. E.; Hansen, G. B.; James, P. B.; Wolff, M. J.

    2005-01-01

    The Martian polar caps have been studied from the time of Herschel. Neither polar cap normally disappears in summer. The Residual North Polar Cap (portion that remains through summer) is composed of a mixture of water ice and dust, and its interannual stability is due to its low sublimation rate at the summer temperatures in the North Polar Region. The Residual South Polar Cap (RSPC) is more enigmatic, surviving the relatively hot perihelic summer season despite being composed of much more volatile CO2. It is able to do so because of its unusually high albedo, which is larger than that of other bright regions in the seasonal cap (e.g. Mountains of Mitchel). The proximity of the albedo of the RSPC to the critical albedo for stability raises the question of whether the RSPC exists in every Martian year. The ground based record is somewhat ambivalent. Douglass and Lowell reported that RSPC suddenly vanished at Ls=297deg in 1894 and did not reappear until Ls=0deg [1], and Kuiper reported that it disappeared in 1956 [2]; but both observations were questioned by contemporaries, who tended to attribute them to obscuring dust. Barker [3] reported a large amount of water vapor over the south polar cap in 1969 that could be attributed to exposure of near surface water ice during partial removal of the CO2 in the RSPC in 1969.

  12. Cortical and cap sedimentation in gravitropic Equisetum roots

    NASA Technical Reports Server (NTRS)

    Ridge, R. W.; Sack, F. D.

    1992-01-01

    Although the rootcap is required for gravitropic sensing, various classical and contemporary data raise the question of whether additional sensing occurs away from the cap in roots. Roots of Equisetum hyemale L. (horsetail) were examined by light and electron microscopy to determine which cell components were distributed with respect to gravity both in and away from the rootcap. Adventitious roots from stem cuttings were gravitropic in a vertical orientation or if reoriented to the horizontal. Obvious amyloplast sedimentation was found in vertical and in reoriented roots 1) in cells in the center of the rootcap and 2) in young, elongating cortical cells located in two to three layers outside the endodermis. These cortical amyloplasts were smaller than cap amyloplasts and, unlike central cap amyloplasts, were occasionally found in the top of the cell. The nucleus was also sedimented on top of the amyloplasts in both cell types, both in vertical and in reoriented roots. Sedimentation of both organelles ceased as cortical cells elongated further or as cap cells became peripheral in location. In both cell types with sedimentation, endoplasmic reticulum was located in the cell periphery, but showed no obvious enrichment near the lower part of the cell in vertical roots. This is the first modern report of sedimentation away from the cap in roots, and it provides structural evidence that gravitropic sensing may not be confined to the cap in all roots.

  13. The root cap: a short story of life and death.

    PubMed

    Kumpf, Robert P; Nowack, Moritz K

    2015-09-01

    Over 130 years ago, Charles Darwin recognized that sensory functions in the root tip influence directional root growth. Modern plant biology has unravelled that many of the functions that Darwin attributed to the root tip are actually accomplished by a particular organ-the root cap. The root cap surrounds and protects the meristematic stem cells at the growing root tip. Due to this vanguard position, the root cap is predisposed to receive and transmit environmental information to the root proper. In contrast to other plant organs, the root cap shows a rapid turnover of short-lived cells regulated by an intricate balance of cell generation, differentiation, and degeneration. Thanks to these particular features, the root cap is an excellent developmental model system, in which generation, differentiation, and degeneration of cells can be investigated in a conveniently compact spatial and temporal frame. In this review, we give an overview of the current knowledge and concepts of root cap biology, focusing on the model plant Arabidopsis thaliana.

  14. Trafficking of Hepatitis C Virus Core Protein during Virus Particle Assembly

    PubMed Central

    Counihan, Natalie A.; Rawlinson, Stephen M.; Lindenbach, Brett D.

    2011-01-01

    Hepatitis C virus (HCV) core protein is directed to the surface of lipid droplets (LD), a step that is essential for infectious virus production. However, the process by which core is recruited from LD into nascent virus particles is not well understood. To investigate the kinetics of core trafficking, we developed methods to image functional core protein in live, virus-producing cells. During the peak of virus assembly, core formed polarized caps on large, immotile LDs, adjacent to putative sites of assembly. In addition, LD-independent, motile puncta of core were found to traffic along microtubules. Importantly, core was recruited from LDs into these puncta, and interaction between the viral NS2 and NS3-4A proteins was essential for this recruitment process. These data reveal new aspects of core trafficking and identify a novel role for viral nonstructural proteins in virus particle assembly. PMID:22028650

  15. Two-headed tetraphosphate cap analogs are inhibitors of the Dcp1/2 RNA decapping complex.

    PubMed

    Ziemniak, Marcin; Mugridge, Jeffrey S; Kowalska, Joanna; Rhoads, Robert E; Gross, John D; Jemielity, Jacek

    2016-04-01

    Dcp1/2 is the major eukaryotic RNA decapping complex, comprised of the enzyme Dcp2 and activator Dcp1, which removes the 5' m(7)G cap from mRNA, committing the transcript to degradation. Dcp1/2 activity is crucial for RNA quality control and turnover, and deregulation of these processes may lead to disease development. The molecular details of Dcp1/2 catalysis remain elusive, in part because both cap substrate (m(7)GpppN) and m(7)GDP product are bound by Dcp1/2 with weak (mM) affinity. In order to find inhibitors to use in elucidating the catalytic mechanism of Dcp2, we screened a small library of synthetic m(7)G nucleotides (cap analogs) bearing modifications in the oligophosphate chain. One of the most potent cap analogs, m(7)GpSpppSm(7)G, inhibited Dcp1/2 20 times more efficiently than m(7)GpppN or m(7)GDP. NMR experiments revealed that the compound interacts with specific surfaces of both regulatory and catalytic domains of Dcp2 with submillimolar affinities. Kinetics analysis revealed that m(7)GpSpppSm(7)G is a mixed inhibitor that competes for the Dcp2 active site with micromolar affinity. m(7)GpSpppSm(7)G-capped RNA undergoes rapid decapping, suggesting that the compound may act as a tightly bound cap mimic. Our identification of the first small molecule inhibitor of Dcp2 should be instrumental in future studies aimed at understanding the structural basis of RNA decapping and may provide insight toward the development of novel therapeutically relevant decapping inhibitors.

  16. North-Polar Martian Cap as Habitat for Elementary Life

    NASA Astrophysics Data System (ADS)

    Wallis, M. K.; Wickramasinghe, J. T.; Wickramasinghe, N. C.

    2008-09-01

    North-polar cap over millenia Atmospheric water in Mars tends currently as for the past millenia to distil onto the polar caps and be buried under dust deposits. Diffusive release from ground-ice (and its excavation in meteorite impacts [1]) replenishes atmospheric water, allowing the gradual build up of polar ice-dust deposits. When sunlit, this warmed and sublimating ice-dust mix has interest as a potential habitat for micro-organisms. Modelling shows precipitable vapour at 10-50μm/yr, varying sensitively with small changes in orbitable obliquity around the present 25° [2]. The modelling applies to a globe with regionally uniform albedo, unlike the steep topography and dark layering of the north polar cap whose upper 300m have accumulated over the last 500 kyr [3]. The cliffs and ravines of the north-polar cap are thought to form through south-facing slopes sublimating and gaining a dirt-encrusted surface, while horizontal surfaces brighten through frost deposits. The two-phase surface derives from the dust and frost feedback on surface albedo [4] and the resulting terrain develops over diurnal cycles of frosting and sublimation, and over annual seasonal cycles. The steep south-facing sides of observed ravines when unshadowed would see for a few hours the full intensity of sunlight at near normal incidence, without the atmospheric dimming at similar inclinations on Earth. As exposed ice sublimates at T > 200K (partial pressure exceeds typical martian 0.1 Pa), a crust of dirt develops to maintain quasi-stability. The dirt crust's main function is to buffer the ice against diurnal temperature fluctuations, but it also slows down vapour diffusion - analogous to south polar ice sublimation [5] and the growth of ground-ice [6]. We envisage 1-10 mm/yr as the net sublimation rate, compatible with the 100 kyr life and scales of the north polar ravines. Modelling of icy-dirt crusts in the polar cap Plane-parallel layers have been used to model the changing temperature

  17. InGaAs/GaAs quantum dot interdiffiusion induced by cap layer overgrowth

    SciTech Connect

    Jasinski, J.; Babinski, A.; Czeczott, M.; Bozek, R.

    2000-06-28

    The effect of thermal treatment during and after growth of InGaAs/GaAs quantum dot (QD) structures was studied. Transmission electron microscopy and atomic force microscopy confirmed the presence of interacting QDs, as was expected from analysis of temperature dependence of QD photoluminescence (PL) peak. The results indicate that the effect of post-growth annealing can be similar to the effect of elevated temperature of capping layer growth. Both, these thermal treatments can lead to a similar In and Ga interdiffiusion resulting in a similar blue-shift of QD PL peak.

  18. Suppressed blinking behavior of thioglycolic acid capped CdTe quantum dot by amine functionalization

    NASA Astrophysics Data System (ADS)

    Mandal, Abhijit; Tamai, Naoto

    2011-12-01

    Prepared water soluble thioglycolic acid capped CdTe quantum dots (QDs) were further surface functionalized by ethylene diamine (EDA). Amine functionalized CdTe QDs demonstrate enhanced luminescence intensity at ensemble measurements and suppressed luminescence intermittency behavior at the single molecule level. A clear decrease in the power law exponent for "on" time behavior is observed in amine modified CdTe QDs. Our results show that surface of CdTe QDs modified by EDA can lead to an important physical mechanism to enhance fluorescence intensity, reduce blinking, and increase photostability.

  19. Tropical Glaciers in the Common Era: Papua, Indonesia, Quelccaya Ice Cap, Peru and Kilimanjaro, Tanzania

    NASA Astrophysics Data System (ADS)

    Thompson, L. G.; Mosley-Thompson, E. S.; Davis, M. E.

    2011-12-01

    High-resolution ice core stratigraphic records of δ18O (temperature proxy) demonstrate that the current warming at high elevations in mid- to lower latitudes is unprecedented for at least the last two millennia, although at many sites the Early Holocene was much warmer than at present. Here we discuss the interaction of El Niño-Southern Oscillation (ENSO) variability and warming trends as recorded in ice core records from high-altitude tropical glaciers and the implications of the warming trends for the future of these glaciers. ENSO has strong impacts on meteorological phenomena that either directly or indirectly affect most regions on the planet and their populations, particularly throughout the Tropics. Here we examine similarities and differences among ice core records from Papua (Indonesia), Quelccaya Ice Cap (Peru) and Kilimanjaro (Tanzania). Quelccaya, Earth's largest tropical ice cap, has provided continuous, annually-resolved proxy records of climatic and environmental variability preserved in many measurable parameters, especially oxygen and hydrogen isotopic ratios (δ18O, δD) and the net mass balance (accumulation) spanning the last 1800 years. The remarkable similarity between changes in the highland and coastal cultures of Peru and climate variability in the Andes, especially with regard to precipitation, implies a strong connection between prehistoric human activities and climate in this region. The well-documented ice loss on Quelccaya, Kilimanjaro in eastern Africa and the ice fields near Puncak Jaya in Papua, Indonesia presents a possible analog for glacier response in the tropics during the Holocene. The ongoing melting of these ice fields is consistent with model predictions of a vertical amplification of temperature in the Tropics. A sequence of over 50 recently exposed, rooted, soft-bodied plant deposits collected between 2002 and 2011 from the retreating margins of the Quelccaya ice cap provide a longer term perspective for the recent

  20. Academic Rigor: The Core of the Core

    ERIC Educational Resources Information Center

    Brunner, Judy

    2013-01-01

    Some educators see the Common Core State Standards as reason for stress, most recognize the positive possibilities associated with them and are willing to make the professional commitment to implementing them so that academic rigor for all students will increase. But business leaders, parents, and the authors of the Common Core are not the only…