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Sample records for acrb crystallisation highlighted

  1. Perspectives on protein crystallisation

    SciTech Connect

    Ochi, T.; Stojanoff, V.; Bolanos-Garcia, V.M.; Moreno, A.

    2009-12-11

    This final part on 'perspectives' is focused on new strategies that can be used to crystallise proteins and improve the crystal quality of macromolecular complexes using any of the methods reviewed in this focused issue. Some advantages and disadvantages, limitations, and plausible applications to high-resolution X-ray crystallography are discussed.

  2. Substrate path in the AcrB multidrug efflux pump of Escherichia coli

    PubMed Central

    Husain, Fasahath; Nikaido, Hiroshi

    2010-01-01

    A major tripartite multidrug efflux pump of Escherichia coli, AcrAB-TolC, confers resistance to a wide variety of compounds. The drug molecule is captured by AcrB probably from the periplasm or the periplasm/inner membrane interface, and is passed through AcrB and then TolC to the medium. Currently there exist numerous crystallographic and mutation data concerning the regions of AcrB and its homologs that may interact with substrates. Starting with these data, we devised fluorescence assays in whole cells to determine the entire substrate path through AcrB. We tested 48 residues in AcrB along the predicted substrate path and 25 gave positive results, based on the covalent labeling of cysteine residues by a lipophilic dye-maleimide and the blocking of Nile Red efflux by covalent labeling with bulky maleimide reagents. These residues are all located in the periplasmic domain, in regions we designate as the lower part of the large external cleft, the cleft itself, the crystallographically defined binding pocket, and the gate between the pocket and the funnel. Our observations suggest that the substrate is captured in the lower cleft region of AcrB, then transported through the binding pocket, the gate, and finally to the AcrB funnel that connects AcrB to TolC. PMID:20804453

  3. Crystallisation driven by sedimentation: a particle resolved study

    NASA Astrophysics Data System (ADS)

    Turci, Francesco; Royall, C. Patrick

    2016-08-01

    We investigate the effects of the reversal of the gravitational field onto a sedimented and partially crystallised suspension of nearly-hard sphere colloids. We analyse the structural changes that take place during the melting of the crystalline regions and the reorganisation and assembly of the sedimenting particles. Through a comparison with numerical simulation, we access the single-particle kinetics and identify the key structural mechanism in the competition between five-fold symmetric and cubic crystalline structures. With the use of a coarse-grained, discrete model, we reproduce the kinetic network of reactions underpinning crystallisation and highlight the main microscopic transitions.

  4. Detergents in Membrane Protein Purification and Crystallisation.

    PubMed

    Anandan, Anandhi; Vrielink, Alice

    2016-01-01

    Detergents play a significant role in structural and functional characterisation of integral membrane proteins (IMPs). IMPs reside in the biological membranes and exhibit a great variation in their structural and physical properties. For in vitro biophysical studies, structural and functional analyses, IMPs need to be extracted from the membrane lipid bilayer environment in which they are found and purified to homogeneity while maintaining a folded and functionally active state. Detergents are capable of successfully solubilising and extracting the IMPs from the membrane bilayers. A number of detergents with varying structure and physicochemical properties are commercially available and can be applied for this purpose. Nevertheless, it is important to choose a detergent that is not only able to extract the membrane protein but also provide an optimal environment while retaining the correct structural and physical properties of the protein molecule. Choosing the best detergent for this task can be made possible by understanding the physical and chemical properties of the different detergents and their interaction with the IMPs. In addition, understanding the mechanism of membrane solubilisation and protein extraction along with crystallisation requirements, if crystallographic studies are going to be undertaken, can help in choosing the best detergent for the purpose. This chapter aims to present the fundamental properties of detergents and highlight information relevant to IMP crystallisation. The first section of the chapter reviews the physicochemical properties of detergents and parameters essential for predicting their behaviour in solution. The second section covers the interaction of detergents with the biologic membranes and proteins followed by their role in membrane protein crystallisation. The last section will briefly cover the types of detergent and their properties focusing on custom designed detergents for membrane protein studies. PMID:27553232

  5. Substrate binding accelerates the conformational transitions and substrate dissociation in multidrug efflux transporter AcrB

    PubMed Central

    Wang, Beibei; Weng, Jingwei; Wang, Wenning

    2015-01-01

    The tripartite efflux pump assembly AcrAB-TolC is the major multidrug resistance transporter in E. coli. The inner membrane transporter AcrB is a homotrimer, energized by the proton movement down the transmembrane electrochemical gradient. The asymmetric crystal structures of AcrB with three monomers in distinct conformational states [access (A), binding (B) and extrusion (E)] support a functional rotating mechanism, in which each monomer of AcrB cycles among the three states in a concerted way. However, the relationship between the conformational changes during functional rotation and drug translocation has not been totally understood. Here, we explored the conformational changes of the AcrB homotrimer during the ABE to BEA transition in different substrate-binding states using targeted MD simulations. It was found that the dissociation of substrate from the distal binding pocket of B monomer is closely related to the concerted conformational changes in the translocation pathway, especially the side chain reorientation of Phe628 and Tyr327. A second substrate binding at the proximal binding pocket of A monomer evidently accelerates the conformational transitions as well as substrate dissociation in B monomer. The acceleration effect of the multi-substrate binding mode provides a molecular explanation for the positive cooperativity observed in the kinetic studies of substrate efflux and deepens our understanding of the functional rotating mechanism of AcrB. PMID:25918513

  6. Structures of Gate Loop Variants of the AcrB Drug Efflux Pump Bound by Erythromycin Substrate

    PubMed Central

    Ababou, Abdessamad; Koronakis, Vassilis

    2016-01-01

    Gram-negative bacteria such as E. coli use tripartite efflux pumps such as AcrAB-TolC to expel antibiotics and noxious compounds. A key feature of the inner membrane transporter component, AcrB, is a short stretch of residues known as the gate/switch loop that divides the proximal and distal substrate binding pockets. Amino acid substitutions of the gate loop are known to decrease antibiotic resistance conferred by AcrB. Here we present two new AcrB gate loop variants, the first stripped of its bulky side chains, and a second in which the gate loop is removed entirely. By determining the crystal structures of the variant AcrB proteins in the presence and absence of erythromycin and assessing their ability to confer erythromycin tolerance, we demonstrate that the gate loop is important for AcrB export activity but is not required for erythromycin binding. PMID:27403665

  7. The degassing and crystallisation behaviour of basaltic lavas

    NASA Astrophysics Data System (ADS)

    Applegarth, L. J.; Tuffen, H.; Pinkerton, H.; James, M. R.

    2010-12-01

    Degassing is a fundamental volcanic process that can play a major role in controlling eruptive styles. Volatile loss during magma ascent and decompression increases the liquidus temperature of the residual melt, resulting in undercooling that can trigger crystallisation (1,2). Late-stage crystallisation and vesiculation are significant factors in controlling the eruptive behaviour of volcanoes of intermediate composition (2), but their effects on basaltic volcanic activity have yet to be fully investigated. We present the results of experiments designed to measure the degassing and crystallisation behaviour of volcanic rocks at temperatures up to 1250°C, using thermo-gravimetric analysis coupled with differential scanning calorimetry and mass spectrometry (TGA-DSC-MS). During TGA-DSC-MS analysis, volatiles released from a sample under a controlled heating programme are identified in a mass spectrometer whilst changes to the sample weight and heat flow are simultaneously recorded. By subjecting samples of basaltic lava and bombs to two heating cycles, we have shown that the onset of degassing (mass loss) is systematically followed by crystallisation (exothermic events) on the first heating cycle. During the second cycle, when the sample has been fully degassed, no mass loss or crystallisation are recorded. Our results also highlight complexities in the processes; in some cases up to four pulses of degassing and crystallisation have been identified during a single heating cycle. Our results allow us to measure the total volatile content of samples, the onset temperatures of degassing and crystallisation and the time lag between the two processes, and the enthalpy, hence percentage, of crystallisation taking place. These results have important implications for our understanding of basaltic volcanic eruptions. During effusive basaltic eruptions, lava can travel many kilometres, threatening property and infrastructure. The final areal flow extent is partly dependent on

  8. Crystallising Experiences among Young Elite Dancers

    ERIC Educational Resources Information Center

    Pickard, Angela; Bailey, Richard

    2009-01-01

    Crystallising experiences are defined as memorable reactions an individual has to some quality or feature of an activity or domain that yields a long-term change in the individual performance and their view of themselves (Walters & Gardner, 1986; Freeman, 1999). This paper explores the nature and consequences of crystallising experiences from…

  9. Molecular Mechanism of MBX2319 Inhibition of Escherichia coli AcrB Multidrug Efflux Pump and Comparison with Other Inhibitors

    PubMed Central

    Vargiu, Attilio V.; Ruggerone, Paolo; Opperman, Timothy J.; Nguyen, Son T.

    2014-01-01

    Efflux pumps of the resistance nodulation division (RND) superfamily, such as AcrB, make a major contribution to multidrug resistance in Gram-negative bacteria. The development of inhibitors of the RND pumps would improve the efficacy of current and next-generation antibiotics. To date, however, only one inhibitor has been cocrystallized with AcrB. Thus, in silico structure-based analysis is essential for elucidating the interaction between other inhibitors and the efflux pumps. In this work, we used computer docking and molecular dynamics simulations to study the interaction between AcrB and the compound MBX2319, a novel pyranopyridine efflux pump inhibitor with potent activity against RND efflux pumps of Enterobacteriaceae species, as well as other known inhibitors (D13-9001, 1-[1-naphthylmethyl]-piperazine, and phenylalanylarginine-β-naphthylamide) and the binding of doxorubicin to the efflux-defective F610A variant of AcrB. We also analyzed the binding of a substrate, minocycline, for comparison. Our results show that MBX2319 binds very tightly to the lower part of the distal pocket in the B protomer of AcrB, strongly interacting with the phenylalanines lining the hydrophobic trap, where the hydrophobic portion of D13-9001 was found to bind by X-ray crystallography. Additionally, MBX2319 binds to AcrB in a manner that is similar to the way in which doxorubicin binds to the F610A variant of AcrB. In contrast, 1-(1-naphthylmethyl)-piperazine and phenylalanylarginine-β-naphthylamide appear to bind to somewhat different areas of the distal pocket in the B protomer of AcrB than does MBX2319. However, all inhibitors (except D13-9001) appear to distort the structure of the distal pocket, impairing the proper binding of substrates. PMID:25114133

  10. Substrate-dependent dynamics of the multidrug efflux transporter AcrB of Escherichia coli

    PubMed Central

    Yamamoto, Kentaro; Tamai, Rei; Yamazaki, Megumi; Inaba, Takehiko; Sowa, Yoshiyuki; Kawagishi, Ikuro

    2016-01-01

    The resistance-nodulation-cell division (RND)-type xenobiotic efflux system plays a major role in the multidrug resistance of gram-negative bacteria. The only constitutively expressed RND system of Escherichia coli consists of the inner membrane transporter AcrB, the membrane fusion protein AcrA, and the outer membrane channel TolC. The latter two components are shared with another RND-type transporter AcrD, whose expression is induced by environmental stimuli. Here, we demonstrate how RND-type ternary complexes, which span two membranes and the cell wall, form in vivo. Total internal reflection fluorescence (TIRF) microscopy revealed that most fluorescent foci formed by AcrB fused to green fluorescent protein (GFP) were stationary in the presence of TolC but showed lateral displacements when tolC was deleted. The fraction of stationary AcrB-GFP foci decreased with increasing levels of AcrD. We propose that the AcrB-containing complex becomes unstable upon the induction of AcrD, which presumably replaces AcrB, a process we call “transporter exchange.” This instability is suppressed by AcrB-specific substrates, suggesting that the ternary complex is stabilised when it is in action. These results suggest that the assembly of the RND-type efflux system is dynamically regulated in response to external stimuli, shedding new light on the adaptive antibiotic resistance of bacteria. PMID:26916090

  11. Substrate-dependent dynamics of the multidrug efflux transporter AcrB of Escherichia coli.

    PubMed

    Yamamoto, Kentaro; Tamai, Rei; Yamazaki, Megumi; Inaba, Takehiko; Sowa, Yoshiyuki; Kawagishi, Ikuro

    2016-01-01

    The resistance-nodulation-cell division (RND)-type xenobiotic efflux system plays a major role in the multidrug resistance of gram-negative bacteria. The only constitutively expressed RND system of Escherichia coli consists of the inner membrane transporter AcrB, the membrane fusion protein AcrA, and the outer membrane channel TolC. The latter two components are shared with another RND-type transporter AcrD, whose expression is induced by environmental stimuli. Here, we demonstrate how RND-type ternary complexes, which span two membranes and the cell wall, form in vivo. Total internal reflection fluorescence (TIRF) microscopy revealed that most fluorescent foci formed by AcrB fused to green fluorescent protein (GFP) were stationary in the presence of TolC but showed lateral displacements when tolC was deleted. The fraction of stationary AcrB-GFP foci decreased with increasing levels of AcrD. We propose that the AcrB-containing complex becomes unstable upon the induction of AcrD, which presumably replaces AcrB, a process we call "transporter exchange." This instability is suppressed by AcrB-specific substrates, suggesting that the ternary complex is stabilised when it is in action. These results suggest that the assembly of the RND-type efflux system is dynamically regulated in response to external stimuli, shedding new light on the adaptive antibiotic resistance of bacteria. PMID:26916090

  12. Molecular basis for inhibition of AcrB multidrug efflux pump by novel and powerful pyranopyridine derivatives.

    PubMed

    Sjuts, Hanno; Vargiu, Attilio V; Kwasny, Steven M; Nguyen, Son T; Kim, Hong-Suk; Ding, Xiaoyuan; Ornik, Alina R; Ruggerone, Paolo; Bowlin, Terry L; Nikaido, Hiroshi; Pos, Klaas M; Opperman, Timothy J

    2016-03-29

    TheEscherichia coliAcrAB-TolC efflux pump is the archetype of the resistance nodulation cell division (RND) exporters from Gram-negative bacteria. Overexpression of RND-type efflux pumps is a major factor in multidrug resistance (MDR), which makes these pumps important antibacterial drug discovery targets. We have recently developed novel pyranopyridine-based inhibitors of AcrB, which are orders of magnitude more powerful than the previously known inhibitors. However, further development of such inhibitors has been hindered by the lack of structural information for rational drug design. Although only the soluble, periplasmic part of AcrB binds and exports the ligands, the presence of the membrane-embedded domain in AcrB and its polyspecific binding behavior have made cocrystallization with drugs challenging. To overcome this obstacle, we have engineered and produced a soluble version of AcrB [AcrB periplasmic domain (AcrBper)], which is highly congruent in structure with the periplasmic part of the full-length protein, and is capable of binding substrates and potent inhibitors. Here, we describe the molecular basis for pyranopyridine-based inhibition of AcrB using a combination of cellular, X-ray crystallographic, and molecular dynamics (MD) simulations studies. The pyranopyridines bind within a phenylalanine-rich cage that branches from the deep binding pocket of AcrB, where they form extensive hydrophobic interactions. Moreover, the increasing potency of improved inhibitors correlates with the formation of a delicate protein- and water-mediated hydrogen bond network. These detailed insights provide a molecular platform for the development of novel combinational therapies using efflux pump inhibitors for combating multidrug resistant Gram-negative pathogens. PMID:26976576

  13. Correlation between AcrB trimer association affinity and efflux activity.

    PubMed

    Ye, Cui; Wang, Zhaoshuai; Lu, Wei; Zhong, Meng; Chai, Qian; Wei, Yinan

    2014-06-17

    The majority of membrane proteins function as oligomers. However, it remains largely unclear how the oligomer stability of protein complexes correlates with their function. Understanding the relationship between oligomer stability and activity is essential to protein research and to virtually all cellular processes that depend on the function of protein complexes. Proteins make lasting or transient interactions as they perform their functions. Obligate oligomeric proteins exist and function exclusively at a specific oligomeric state. Although oligomerization is clearly critical for such proteins to function, a direct correlation between oligomer affinity and biological activity has not yet been reported. Here, we used an obligate trimeric membrane transporter protein, AcrB, as a model to investigate the correlation between its relative trimer affinity and efflux activity. AcrB is a component of the major multidrug efflux system in Escherichia coli. We created six AcrB constructs with mutations at the transmembrane intersubunit interface, and we determined their activities using both a drug susceptibility assay and an ethidium bromide accumulation assay. The relative trimer affinities of these mutants in detergent micelles were obtained using blue native polyacrylamide gel electrophoresis. A correlation between the relative trimer affinity and substrate efflux activity was observed, in which a threshold trimer stability was required to maintain efflux activity. The trimer affinity of the wild-type protein was approximately 3 kcal/mol more stable than the threshold value. Once the threshold was reached, an additional increase of stability in the range observed had no observable effect on protein activity. PMID:24854514

  14. Microgravity protein crystallisation aboard the photon satellite

    NASA Astrophysics Data System (ADS)

    Chayen, Naomi E.

    1995-08-01

    Human immunodeficiency virus (HIV) reverse transcriptase was used as a sample protein to determine whether the optimum conditions for crystallisation in microgravity were identical to those on Earth. The degree of reproducibility of the results in microgravity was also tested. The results showed that, comparing experiments performed in identical apparatus, the conditions for obtaining the largest crystals in microgravity were different from the optimal conditions on Earth. Crystal form, size, visual quality and the reproducibility of the results were no different from those on Earth. Crystallisation took place in the vapour diffusion set-up of the Russian Kashtan apparatus which flew on a Photon satellite (4-20 October 1991).

  15. On the reaction coordinate for seeded crystallisation

    NASA Astrophysics Data System (ADS)

    Jungblut, Swetlana; Dellago, Christoph

    2015-09-01

    Small pre-structured seeds introduced into an undercooled fluid are known to increase the crystal nucleation rate by some orders of magnitude, if the structure of the seeds is commensurate with the bulk crystalline phase. The presence of such seeds also alters the crystallisation mechanism by favouring particular structures at the early stages of the nucleation process. Here, we study with computer simulations the effect of small face-centred cubic and body-centred cubic seeds on the crystallisation of a Lennard-Jones liquid in the strongly undercooled regime. We find that seeds with body-centred cubic structure lead to a larger enhancement of the crystallisation rate than face-centred cubic seeds. An analysis of recurrence times reveals that the size of the largest crystalline cluster used as reaction coordinate is affected by pronounced memory effects, which depend on the particular seed structure and point to the importance of structural information in the definition of a good reaction coordinate for crystallisation.

  16. Salt and ice crystallisation in porous sandstones

    NASA Astrophysics Data System (ADS)

    Ruedrich, Joerg; Siegesmund, Siegfried

    2007-03-01

    Salt and ice crystallisation in the pore spaces causes major physical damage to natural building stones. The damaging effect of these processes can be traced back to physically induced stress inside of the rock while crystallizing. The increasing scientific research done during the past century has shown that there are numerous parameters that have an influence on the weathering resulting from these processes. However, the working mechanisms of the stress development within the rock and its material dependency are still subject to discussion. This article gives an overview of salt and ice weathering. Additionally, laboratory results of various sandstones examined are presented. Salt crystallisation tests and freeze/thaw tests were done to obtain information about how crystallisation weathering depends on material characteristics such as pore space, water transportation, and mechanical features. Simultaneous measuring of the length alternating during the salt and ice crystallisation has revealed detailed information on the development of crystal in the pore spaces as well as the development of stress. These findings can help to understand the damaging mechanisms.

  17. Stepwise substrate translocation mechanism revealed by free energy calculations of doxorubicin in the multidrug transporter AcrB

    PubMed Central

    Zuo, Zhicheng; Weng, Jingwei; Wang, Wenning

    2015-01-01

    AcrB is the inner membrane transporter of the tripartite multidrug efflux pump AcrAB-TolC in E. coli, which poses a major obstacle to the treatment of bacterial infections. X-ray structures have identified two types of substrate-binding pockets in the porter domains of AcrB trimer: the proximal binding pocket (PBP) and the distal binding pocket (DBP), and suggest a functional rotating mechanism in which each protomer cycles consecutively through three distinct conformational states (access, binding and extrusion). However, the details of substrate binding and translocation between the binding pockets remain elusive. In this work, we performed atomic simulations to obtain the free energy profile of the translocation of an antibiotic drug doxorubicin (DOX) inside AcrB. Our simulation indicates that DOX binds at the PBP and DBP with comparable affinities in the binding state protomer, and overcomes a 3 kcal/mol energy barrier to transit between them. Obvious conformational changes including closing of the PC1/PC2 cleft and shrinking of the DBP were observed upon DOX binding in the PBP, resulting in an intermediate state between the access and binding states. Taken together, the simulation results reveal a detailed stepwise substrate binding and translocation process in the framework of functional rotating mechanism. PMID:26365278

  18. The influence of cooling, crystallisation and re-melting on the interpretation of geodetic signals in volcanic systems

    NASA Astrophysics Data System (ADS)

    Caricchi, Luca; Biggs, Juliet; Annen, Catherine; Ebmeier, Susanna

    2014-02-01

    Deformation of volcanic edifices is typically attributed to the movement of magma within the volcanic plumbing system, but a wide range of magmatic processes are capable of producing significant volume variations and may also produce deformation. In order to understand the evolution of magmatic systems prior to eruption and correctly interpret monitoring signals, it is necessary to quantify the patterns and timescales of surface deformation that processes such as crystallisation, degassing and expansion of the hydrothermal system can produce. We show how the combination of petrology and thermal modelling can be applied to geodetic observations to identify the processes occurring in a magmatic reservoir during volcanic unrest. Thermal modelling and petrology were used to determine the timescales and volumetric variations associated with cooling, crystallisation and gas exsolution. These calculations can be performed rapidly and highlight the most likely processes responsible for the variation of a set of monitoring parameters. We then consider the magnitude and timescales of deformation produced by other processes occurring within the vicinity of an active magma system. We apply these models to a time series of geodetic data spanning the period between the 1997 and 2008 eruptions of Okmok volcano, Aleutians, examining scenarios involving crystallisation, degassing and remelting of the crystallising shallow magmatic body and including a viscoelastic shell or hydrothermal system. The geodetic observations are consistent with the injection of a water-saturated basalt, followed by minor crystallisation and degassing. Other scenarios are not compatible either with the magnitude or rate of the deformation signals.

  19. G-SIMS of crystallisable organics

    NASA Astrophysics Data System (ADS)

    Gilmore, I. S.; Seah, M. P.

    2003-01-01

    In this study, the gentle SIMS (G-SIMS) concept has been applied to the crystallisable organic materials of Irganox 1010, caffeine, cholesterol, glucose, poly- L-lysine and bovine serum albumin. These are chosen to represent as wide a range of material types as possible. For each case, the G-SIMS spectra are considerably simpler than the static SIMS, enabling direct interpretation and identification. It is demonstrated that the amount of fragmentation in the mass spectrum may be controlled numerically and this information can be used to re-assemble the parent molecule. Wherever possible, the use of dual column ion beams is recommended to eliminate alignment requirements. Additionally, the total electron beam fluence should be kept below 6×10 18 electrons/m 2 to prevent electron damage.

  20. Improving olefin tolerance and production in E. coli using native and evolved AcrB

    DOE PAGESBeta

    Mingardon, Florence; Clement, Camille; Hirano, Kathleen; Nhan, Melissa; Luning, Eric G.; Chanal, Angelique; Mukhopadhyay, Aindrila

    2015-01-20

    Microorganisms can be engineered for the production of chemicals utilized in the polymer industry. However many such target compounds inhibit microbial growth and might correspondingly limit production levels. Here, we focus on compounds that are precursors to bioplastics, specifically styrene and representative alpha-olefins; 1-hexene, 1-octene, and 1-nonene. We evaluated the role of the Escherichia coli efflux pump, AcrAB-TolC, in enhancing tolerance towards these olefin compounds. AcrAB-TolC is involved in the tolerance towards all four compounds in E. coli. Both styrene and 1-hexene are highly toxic to E. coli. Styrene is a model plastics precursor with an established route for productionmore » in E. coli (McKenna and Nielsen, 2011). Though our data indicates that AcrAB-TolC is important for its optimal production, we observed a strong negative selection against the production of styrene in E. coli. Thus we used 1-hexene as a model compound to implement a directed evolution strategy to further improve the tolerance phenotype towards this alpha-olefin. We focused on optimization of AcrB, the inner membrane domain known to be responsible for substrate binding, and found several mutations (A279T, Q584R, F617L, L822P, F927S, and F1033Y) that resulted in improved tolerance. Several of these mutations could also be combined in a synergistic manner. Our study shows efflux pumps to be an important mechanism in host engineering for olefins, and one that can be further improved using strategies such as directed evolution, to increase tolerance and potentially production.« less

  1. Promoting crystallisation of the Salmonella enteritidis fimbriae 14 pilin SefD using deuterium oxide

    SciTech Connect

    Liu, Bing; Garnett, James A.; Lee, Wei-chao; Lin, Jing; Salgado, Paula; Taylor, Jonathan; Xu, Yingqi; Lambert, Sebastian; Cota, Ernesto; Matthews, Steve

    2012-05-04

    Highlights: Black-Right-Pointing-Pointer The benefits of D{sub 2}O in screening for crystallisation was explored. Black-Right-Pointing-Pointer The crystal structures of the SefD pilin in both H{sub 2}O and D{sub 2}O reveal differences. Black-Right-Pointing-Pointer Crystallisation improvements are explained by altered interactions in D{sub 2}O crystals. Black-Right-Pointing-Pointer D{sub 2}O is useful additive in sparse-matrix screening for crystallisation. -- Abstract: The use of heavy water (D{sub 2}O) as a solvent is commonplace in many spectroscopic techniques for the study of biological macromolecules. A significant deuterium isotope effect exists where hydrogen-bonding is important, such as in protein stability, dynamics and assembly. Here we illustrate the use of D{sub 2}O in additive screening for the production of reproducible diffraction-quality crystals for the Salmonella enteritidis fimbriae 14 (SEF14) putative tip adhesin, SefD.

  2. Phosphorus removal using novel crystallisation technology.

    PubMed

    Wood, K; Wood, G; Prokop, D; Lewyille, F

    2006-01-01

    A soy protein manufacturing facility was faced with the challenge of reducing its effluent phosphorus (P) content from 20-50 mg L(-1) down to <2 mg L(-1) total P without increasing soluble salt levels to comply with discharge and receiving water requirements. A number of biological and chemical P removal technologies previously evaluated either failed to achieve the new standards or would have produced prohibitive amounts of residual sludge and unacceptably high effluent salt concentrations. Lime precipitation, utilising a novel crystallisation technology, was demonstrated through on-site pilot testing to meet the process objectives. It is capable of achieving the required P removal at pH 10 while not increasing soluble salts and producing rapid settling and filterable particles. Also, minimal carbonate removal was observed with residual solids generation being only 40% of a complete lime softening reaction. This paper describes the technical evaluation that led to the full-scale treatment system that was put into operation in late 2005. PMID:16889253

  3. Coupling of remote alternating-access transport mechanisms for protons and substrates in the multidrug efflux pump AcrB

    PubMed Central

    Eicher, Thomas; Seeger, Markus A; Anselmi, Claudio; Zhou, Wenchang; Brandstätter, Lorenz; Verrey, François; Diederichs, Kay; Faraldo-Gómez, José D; Pos, Klaas M

    2014-01-01

    Membrane transporters of the RND superfamily confer multidrug resistance to pathogenic bacteria, and are essential for cholesterol metabolism and embryonic development in humans. We use high-resolution X-ray crystallography and computational methods to delineate the mechanism of the homotrimeric RND-type proton/drug antiporter AcrB, the active component of the major efflux system AcrAB-TolC in Escherichia coli, and one most complex and intriguing membrane transporters known to date. Analysis of wildtype AcrB and four functionally-inactive variants reveals an unprecedented mechanism that involves two remote alternating-access conformational cycles within each protomer, namely one for protons in the transmembrane region and another for drugs in the periplasmic domain, 50 Å apart. Each of these cycles entails two distinct types of collective motions of two structural repeats, coupled by flanking α-helices that project from the membrane. Moreover, we rationalize how the cross-talk among protomers across the trimerization interface might lead to a more kinetically efficient efflux system. DOI: http://dx.doi.org/10.7554/eLife.03145.001 PMID:25248080

  4. Crystallisation of minerals from concentrated saline dairy effluent.

    PubMed

    Kezia, K; Lee, J; Zisu, B; Weeks, M; Chen, G; Gras, S; Kentish, S

    2016-09-15

    An understanding of crystallisation within saline effluents is important for the design of both brine crystallisers and brine disposal ponds. In this work, crystallisation of a saline effluent concentrate from the Australian dairy industry has been examined at 22 wt% and 30 wt% total solids and at temperatures between 10 and 70 °C. The precipitation occurs more rapidly at higher temperatures. This trend is dictated by precipitation of calcium phosphate salts, albeit the major constituents of the mixture are NaCl and lactose. The crystallisation induction time can be shortened by introducing cavitation induced by ultrasound. In particular, the use of two short acoustic pulses between 3.7 J/g and 16 J/g at 20 kHz spaced ten minutes apart has maximum impact upon both induction time and crystal size. It is believed that the first ultrasound pulse either generates new nuclei or enhances the mass transfer of solute toward the surface of sub-micron growing crystals. Conversely, the second pulse disrupts the growing crystals and forms secondary nuclei. The ultrasound cannot shift the solution equilibrium and so is not able to improve the low crystal yield. To increase this total yield, further evaporation is necessary. The work provides direction to personnel in the dairy industry of the feasibility of brine crystallisation with respect to energy demand and solid recovery. PMID:27267478

  5. Membrane Protein Crystallisation: Current Trends and Future Perspectives.

    PubMed

    Parker, Joanne L; Newstead, Simon

    2016-01-01

    Alpha helical membrane proteins are the targets for many pharmaceutical drugs and play important roles in physiology and disease processes. In recent years, substantial progress has been made in determining their atomic structure using X-ray crystallography. However, a major bottleneck still remains; the identification of conditions that give crystals that are suitable for structure determination. Over the past 10 years we have been analysing the crystallisation conditions reported for alpha helical membrane proteins with the aim to facilitate a rational approach to the design and implementation of successful crystallisation screens. The result has been the development of MemGold, MemGold2 and the additive screen MemAdvantage. The associated analysis, summarised and updated in this chapter, has revealed a number of surprisingly successfully strategies for crystallisation and detergent selection. PMID:27553235

  6. Switch-Loop Flexibility Affects Transport of Large Drugs by the Promiscuous AcrB Multidrug Efflux Transporter

    PubMed Central

    Cha, Hi-jea; Müller, Reinke T.

    2014-01-01

    Multidrug efflux transporters recognize a variety of structurally unrelated compounds for which the molecular basis is poorly understood. For the resistance nodulation and cell division (RND) inner membrane component AcrB of the AcrAB-TolC multidrug efflux system from Escherichia coli, drug binding occurs at the access and deep binding pockets. These two binding areas are separated by an 11-amino-acid-residue-containing switch loop whose conformational flexibility is speculated to be essential for drug binding and transport. A G616N substitution in the switch loop has a distinct and local effect on the orientation of the loop and on the ability to transport larger drugs. Here, we report a distinct phenotypical pattern of drug recognition and transport for the G616N variant, indicating that drug substrates with minimal projection areas of >70 Å2 are less well transported than other substrates. PMID:24914123

  7. A Fluorescent Microplate Assay Quantifies Bacterial Efflux and Demonstrates Two Distinct Compound Binding Sites in AcrB

    PubMed Central

    Ferrari, Annette; Rijnbrand, R.; Erwin, Alice L.

    2015-01-01

    A direct assay of efflux by Escherichia coli AcrAB-TolC and related multidrug pumps would have great value in discovery of new Gram-negative antibiotics. The current understanding of how efflux is affected by the chemical structure and physical properties of molecules is extremely limited, derived from antibacterial data for compounds that inhibit growth of wild-type E. coli. We adapted a previously described fluorescent efflux assay to a 96-well microplate format that measured the ability of test compounds to compete for efflux with Nile Red (an environment-sensitive fluor), independent of antibacterial activity. We show that Nile Red and the lipid-sensitive probe DiBAC4-(3) [bis-(1,3-dibutylbarbituric acid)-trimethine oxonol] can quantify efflux competition in E. coli. We extend the previous findings that the tetracyclines compete with Nile Red and show that DiBAC4-(3) competes with macrolides. The extent of the competition shows a modest correlation with the effect of the acrB deletion on MICs within the compound sets for both dyes. Crystallographic studies identified at least two substrate binding sites in AcrB, the proximal and distal pockets. High-molecular-mass substrates bound the proximal pocket, while low-mass substrates occupied the distal pocket. As DiBAC4-(3) competes with macrolides but not with Nile Red, we propose that DiBAC4-(3) binds the proximal pocket and Nile Red likely binds the distal site. In conclusion, competition with fluorescent probes can be used to study the efflux process for diverse chemical structures and may provide information as to the site of binding and, in some cases, enable rank-ordering a series of related compounds by efflux. PMID:25645845

  8. Kinetics of the reversible reaction of struvite crystallisation.

    PubMed

    Crutchik, D; Garrido, J M

    2016-07-01

    The crystallisation of struvite could be a sustainable and economical alternative for recovering phosphorus from wastewater streams with high phosphate concentrations. Knowledge regarding the kinetics and thermodynamics that are involved in the crystallisation of struvite is the key to determine the optimal conditions for obtaining an efficient process. This study was conducted in a continuous stirred batch reactor. Different sets of experiments were performed in which struvite was either dissolved (undersaturated) or precipitated (oversaturated). These experiments were conducted at different temperatures (25, 30 and 35 °C) and pH values (8.2, 8.5 and 8.8) to determine the kinetics of struvite precipitation and dissolution. Struvite crystallisation was modelled as a reversible reaction. The kinetic rate parameters of struvite precipitation were 1.03·10(-4), 1.25·10(-4) and 1.54·10(-4) mol m(-2) min(-1) at 25, 30 and 35 °C, respectively. Similar kinetic rate parameters were determined for struvite dissolution. Struvite heterogeneous crystallisation can be represented by a first-order kinetic model that fitted well the experimental data. PMID:27085317

  9. Evidence of a Substrate-Discriminating Entrance Channel in the Lower Porter Domain of the Multidrug Resistance Efflux Pump AcrB.

    PubMed

    Schuster, Sabine; Vavra, Martina; Kern, Winfried V

    2016-07-01

    Efflux pumps of the resistance nodulation cell division (RND) transporter family, such as AcrB of Escherichia coli, play an important role in the development of multidrug resistance, but the molecular basis for their substrate promiscuity is not yet completely understood. From a collection of highly clarithromycin-resistant AcrB periplasmic domain mutants derived from in vitro random mutagenesis, we identified variants with an unusually altered drug resistance pattern characterized by increased susceptibility to many drugs of lower molecular weight, including fluoroquinolones, tetracyclines, and oxazolidinones, but unchanged or increased resistance to drugs of higher molecular weight, including macrolides. Sequencing of 14 such "divergent resistance" phenotype mutants and 15 control mutants showed that this unusual phenotype was associated with mutations at residues I38 and I671 predominantly to phenylalanine and threonine, respectively, both conferring a similar susceptibility pattern. Reconstructed I38F and I671T single mutants as well as an engineered I38F I671T double mutant with proved efflux competence revealed an equivalent phenotype with enhanced or unchanged resistance to many large AcrB substrates but increased susceptibility to several lower-molecular-weight drugs known to bind within the distal binding pocket. The two isoleucines located in close vicinity to each other in the lower porter domain of AcrB beneath the bottom of the proximal binding pocket may be part of a preferential small-drug entrance pathway that is compromised by the mutations. This finding supports recent indications of distinct entrance channels used by compounds with different physicochemical properties, of which molecular size appears to play a prominent role. PMID:27161641

  10. Enhancing tolerance to short-chain alcohols by engineering the Escherichia coli AcrB efflux pump to secrete the non-native substrate n-butanol.

    PubMed

    Fisher, Michael A; Boyarskiy, Sergey; Yamada, Masaki R; Kong, Niwen; Bauer, Stefan; Tullman-Ercek, Danielle

    2014-01-17

    The microbial conversion of sugars to fuels is a promising technology, but the byproducts of biomass pretreatment processes and the fuels themselves are often toxic at industrially relevant levels. One promising solution to these problems is to engineer efflux pumps to secrete fuels and inhibitory chemicals from the cell, increasing microbial tolerance and enabling higher fuel titer. Toward that end, we used a directed evolution strategy to generate variants of the Escherichia coli AcrB efflux pump that act on the non-native substrate n-butanol, enhancing growth rates of E. coli in the presence of this biofuel by up to 25%. Furthermore, these variants confer improved tolerance to isobutanol and straight-chain alcohols up to n-heptanol. Single amino acid changes in AcrB responsible for this phenotype were identified. We have also shown that both the chemical and genetic inactivation of pump activity eliminate the tolerance conferred by AcrB pump variants, supporting our assertion that the variants secrete the non-native substrates. This strategy can be applied to create an array of efflux pumps that modulate the intracellular concentrations of small molecules of interest to microbial fuel and chemical production. PMID:23991711

  11. Crystallisation of Ge nanoclusters in SiO 2 caused by electron irradiation in TEM

    NASA Astrophysics Data System (ADS)

    Klimenkov, M.; Matz, W.; Nepijko, S. A.; Lehmann, M.

    2001-07-01

    Ge nanoparticles fabricated by ion implantation technique in SiO 2 thin film crystallise after irradiation with a high-energy electron beam. The crystallisation process depends on the irradiation fluence and flux. Irradiation with a fluence above 6×10 3 C/ cm2 results in cluster growth and above 4×10 4 C/ cm2 in crystallisation. An irradiation with flux below 150 A/cm 2 leads to the crystallisation of Ge nanoparticles in the form of single crystals. For irradiation flux above this value the formation of twinned and multiply twinned particles (MTP) was observed.

  12. An investigation of the effects of self-assembled monolayers on protein crystallisation.

    PubMed

    Zhang, Chen-Yan; Shen, He-Fang; Wang, Qian-Jin; Guo, Yun-Zhu; He, Jin; Cao, Hui-Ling; Liu, Yong-Ming; Shang, Peng; Yin, Da-Chuan

    2013-01-01

    Most protein crystallisation begins from heterogeneous nucleation; in practice, crystallisation typically occurs in the presence of a solid surface in the solution. The solid surface provides a nucleation site such that the energy barrier for nucleation is lower on the surface than in the bulk solution. Different types of solid surfaces exhibit different surface energies, and the nucleation barriers depend on the characteristics of the solid surfaces. Therefore, treatment of the solid surface may alter the surface properties to increase the chance to obtain protein crystals. In this paper, we propose a method to modify the glass cover slip using a self-assembled monolayer (SAM) of functional groups (methyl, sulfydryl and amino), and we investigated the effect of each SAM on protein crystallisation. The results indicated that both crystallisation success rate in a reproducibility study, and crystallisation hits in a crystallisation screening study, were increased using the SAMs, among which, the methyl-modified SAM demonstrated the most significant improvement. These results illustrated that directly modifying the crystallisation plates or glass cover slips to create surfaces that favour heterogeneous nucleation can be potentially useful in practical protein crystallisation, and the utilisation of a SAM containing a functional group can be considered a promising technique for the treatment of the surfaces that will directly contact the crystallisation solution. PMID:23749116

  13. Improving olefin tolerance and production in E. coli using native and evolved AcrB

    SciTech Connect

    Mingardon, Florence; Clement, Camille; Hirano, Kathleen; Nhan, Melissa; Luning, Eric G.; Chanal, Angelique; Mukhopadhyay, Aindrila

    2015-01-20

    Microorganisms can be engineered for the production of chemicals utilized in the polymer industry. However many such target compounds inhibit microbial growth and might correspondingly limit production levels. Here, we focus on compounds that are precursors to bioplastics, specifically styrene and representative alpha-olefins; 1-hexene, 1-octene, and 1-nonene. We evaluated the role of the Escherichia coli efflux pump, AcrAB-TolC, in enhancing tolerance towards these olefin compounds. AcrAB-TolC is involved in the tolerance towards all four compounds in E. coli. Both styrene and 1-hexene are highly toxic to E. coli. Styrene is a model plastics precursor with an established route for production in E. coli (McKenna and Nielsen, 2011). Though our data indicates that AcrAB-TolC is important for its optimal production, we observed a strong negative selection against the production of styrene in E. coli. Thus we used 1-hexene as a model compound to implement a directed evolution strategy to further improve the tolerance phenotype towards this alpha-olefin. We focused on optimization of AcrB, the inner membrane domain known to be responsible for substrate binding, and found several mutations (A279T, Q584R, F617L, L822P, F927S, and F1033Y) that resulted in improved tolerance. Several of these mutations could also be combined in a synergistic manner. Our study shows efflux pumps to be an important mechanism in host engineering for olefins, and one that can be further improved using strategies such as directed evolution, to increase tolerance and potentially production.

  14. Phosphorus removal from soy protein wastewater using novel crystallisation technology.

    PubMed

    Wood, K; Wood, G; Prokop, D; Lewyllie, F

    2007-01-01

    The objective of this work was to identify and implement a treatment method that would reduce the phosphorus (P) content of soy protein isolate manufacturing wastewater to an average of 2 mg L(-1) total P without increasing soluble salts in order to comply with discharge and receiving-water requirements. A novel crystallisation technology was evaluated through pilot studies that demonstrated these objectives could be met. Rapid settling (3.6 cm min(-1)) and filterable particles (65% filter cake dry solids content) were produced with lime precipitation at 10.0-10.2 pH in the high-aspect ratio, draft tube crystalliser (HARDTAC). Crystal growth in the full-scale system has yielded mean particle sizes of >60 microm. Also, minimal carbonate removal resulted in residual sludge generation of 0.6-0.8 g and lime consumption of 0.40-0.75 g per litre treated, which is substantially less than with a complete softening reaction. This paper describes the technical evaluation and full-scale treatment system that has been in operation since late 2005. PMID:17564367

  15. Coalescence-induced crystallisation wave in Pd nanoparticles

    PubMed Central

    Grammatikopoulos, Panagiotis; Cassidy, Cathal; Singh, Vidyadhar; Sowwan, Mukhles

    2014-01-01

    Palladium nanoparticles offer an attractive alternative to bulk palladium for catalysis, hydrogen storage and gas sensing applications. Their performance depends strongly on surface structure; therefore, nanoparticle coalescence can play an important role, as it determines the resultant structure of the active sites where reactions (e.g. catalysis) actually take place, i.e. facets, edges, vertices or protrusions. With this in mind, we performed classical molecular dynamics (MD) simulations and magnetron-sputtering inert gas condensation depositions of palladium nanoparticles, supported by high-resolution transmission electron microscopy (HRTEM), to study the mechanisms that govern their coalescence. Surface energy minimisation drove the interactions initially, leading to the formation of an interface/neck, as expected. Intriguingly, at a later stage, atomic rearrangements triggered a crystallisation wave propagating through the amorphous nanoparticles, leading to mono- or polycrystalline fcc structures. In the case of crystalline nanoparticles, almost-epitaxial alignment occurred and the formation of twins and surface protrusions were observed. PMID:25047807

  16. An X-ray diffraction analysis of crystallised whey and whey-permeate powders.

    PubMed

    Nijdam, Justin; Ibach, Alexander; Eichhorn, Klaus; Kind, Matthias

    2007-11-26

    Amorphous whey, whey-permeate and lactose powders have been crystallised at various air temperatures and humidities, and these crystallised powders have been examined using X-ray diffraction. The most stable lactose crystal under normal storage conditions, alpha-lactose monohydrate, forms preferentially in whey and whey-permeate powders at 50 degrees C, provided sufficient moisture is available, whereas anhydrous beta-lactose and mixed anhydrous lactose crystals, which are unstable under normal storage conditions, form preferentially at 90 degrees C. Thus, faster crystallisation at higher temperatures is offset by the formation of lactose-crystal forms that are less stable under normal storage conditions. Very little alpha-lactose monohydrate crystallised in the pure lactose powders over the range of temperatures and humidities tested, because the crystallisation of alpha- and beta-lactose is considerably more rapid than the mutarotation of beta- to alpha-lactose in the amorphous phase and the hydration of alpha-lactose during crystallisation. Protein and salts hinder the crystallisation process, which provides more time for mutarotation and crystal hydration in the whey and whey-permeate powders. PMID:17719020

  17. Research Highlights

    ERIC Educational Resources Information Center

    Australian Council for Educational Research, 2004

    2004-01-01

    This document is an annual publication documenting developments in the Australian Council for Educational Research (ACER)'s research programs for the previous year. The 2004 edition highlights research on the following themes: (1) Helping international schools measure achievement; (2) Evaluating Australian teachers; (3) Tests of reading…

  18. Three ways in, one way out: water dynamics in the trans-membrane domains of the inner membrane translocase AcrB.

    PubMed

    Fischer, Nadine; Kandt, Christian

    2011-10-01

    Powered by proton-motive force, the inner membrane translocase AcrB is the engine of the AcrAB-TolC efflux pump in Escherichia coli. As proton conduction in proteins occurs along hydrogen-bonded networks of polar residues and water molecules, knowledge of the protein-internal water distribution and water-interacting residues allows drawing conclusions to possible pathways of proton conduction. Here, we report a series of 6× 50 ns independent molecular dynamics simulations of asymmetric AcrB embedded in a phospholipid/water environment. Simulating each monomer in its proposed protonation state, we calculated for each trans-membrane domain the average water distribution, identified residues interacting with these waters and quantified each residue's frequency of water hydrogen bond contact. Combining this information we find three possible routes of proton transfer connecting a continuously hydrated region of known key residues in the TMD interior to bulk water by one cytoplasmic and up to three periplasm water channels in monomer B and A. We find that water access of the trans-membrane domains is regulated by four groups of residues in a combination of side chain re-orientations and shifts of trans-membrane helices. Our findings support a proton release event via Arg971 during the C intermediate or in the transition to A, and proton uptake occurring in the A or B state or during a so far unknown intermediate in between B and C where cytoplasmic water access is still possible. Our simulations suggest experimentally testable hypotheses, which have not been investigated so far. PMID:21905112

  19. Brilliant crystallisation in the anterior chamber and subretinal space following adjunctive intravitreal ranibizumab for diabetic vitrectomy

    PubMed Central

    Bastion, Mae-Lynn Catherine; Mustapha, Mushawiahti; Ho, Ivan

    2012-01-01

    To report a unique case of crystallisation in the anterior chamber and subretinal space in a Malay lady following inadvertent subretinal injection of ranibizumab prior to vitrectomy for proliferative diabetic retinopathy. PMID:23093508

  20. Effects of emulsion droplet sizes on the crystallisation of milk fat.

    PubMed

    Truong, Tuyen; Bansal, Nidhi; Sharma, Ranjan; Palmer, Martin; Bhandari, Bhesh

    2014-02-15

    The crystallisation properties of milk fat emulsions containing dairy-based ingredients as functions of emulsion droplet size, cooling rate, and emulsifier type were investigated using a differential scanning calorimeter (DSC). Anhydrous milk fat and its fractions (stearin and olein) were emulsified with whey protein concentrate, sodium caseinate, and Tween80 by homogenisation to produce emulsions in various size ranges (0.13-3.10 μm). Particle size, cooling rate, and types of emulsifier all had an influence on the crystallisation properties of fat in the emulsions. In general, the crystallisation temperature of emulsified fats decreased with decreasing average droplet size and was of an exponent function of size, indicating that the influence of particle size on crystallisation temperature is more pronounced in the sub-micron range. This particle size effect was also verified by electron microscopy. PMID:24128537

  1. Brilliant crystallisation in the anterior chamber and subretinal space following adjunctive intravitreal ranibizumab for diabetic vitrectomy.

    PubMed

    Bastion, Mae-Lynn Catherine; Mustapha, Mushawiahti; Ho, Ivan

    2012-01-01

    To report a unique case of crystallisation in the anterior chamber and subretinal space in a Malay lady following inadvertent subretinal injection of ranibizumab prior to vitrectomy for proliferative diabetic retinopathy. PMID:23093508

  2. Isotopic composition of water of crystallisation of sulfates of Permian-Triassic age, Eastern Alps, Austria

    NASA Astrophysics Data System (ADS)

    Bojar, Ana-Voica; Halas, Stanislaw; Trembaczowski, Andrzej; Bojar, Hans-Peter

    2016-04-01

    The investigated sulfates as gypsum and polyhalite were selected from various gypsum and halite rich deposits of the Northern Calcareous Alps and the Central Alpine Mesozoic. The two units of the Eastern Alps are characterised by the presence of Permian-Triassic evaporitic deposits. Crystallisation water of mineral phases was extracted by heating the samples under vacuum. The cryogenically trapped water was subsequently analysed for delta 18O and delta D on a Picarro L2120-i Analyzer. The isotopic compositions were synchronously measured, with a standard deviation better than 0.1 permil. The fractionation factors for both oxygen and hydrogen between brine where the sulfates formed and crystallisation water of sulfates are not temperature dependent. Using the appropriate relationships, we conclude from the calculations that, for gypsum, oxygen and hydrogen isotopic composition of fluid in equilibrium with crystallisation water varied between -16 to -6 permil and between -90 to -25 permil, respectively. The crystallization water of gypsum associated with halite type deposits has heavier isotopic compositions. The isotopic composition of crystallisation water of gypsum points towards reequilibration with a younger meteoric fluid. In contrast, polyhalite crystallisation water show much heavier values between +10 to +11 permil for oxygen and +16 to +19 permil for hydrogen. These values suggest the fact that this water of crystallisation indicates the isotopic composition of brines. The origin of these brines, diagenetic versus later thermal overprint is subject of further investigations. All the measured values plot along a regression line.

  3. Target selection for structural genomics based on combining fold recognition and crystallisation prediction methods: application to the human proteome.

    PubMed

    Bray, James E

    2012-03-01

    The objective of this study is to automatically identify regions of the human proteome that are suitable for 3D structure determination by X-ray crystallography and to annotate them according to their likelihood to produce diffraction quality crystals. The results provide a powerful tool for structural genomics laboratories who wish to select human proteins based on the statistical likelihood of crystallisation success. Combining fold recognition and crystallisation prediction algorithms enables the efficient calculation of the crystallisability of the entire human proteome. This novel study estimates that there are approximately 40,000 crystallisable regions in the human proteome. Currently, only 15% of these regions (approx. 6,000 sequences) have been solved to at least 95% sequence identity. The remaining unsolved regions have been categorised into 5 crystallisation classes and an integral membrane protein (IMP) class, based on established structure prediction, crystallisation prediction and transmembrane (TM) helix prediction algorithms. Approximately 750 unsolved regions (2% of the proteome) have been identified as having a PDB fold representative (template) and an 'optimal' likelihood of crystallisation. At the other end of the spectrum, more than 10,500 non-IMP regions with a PDB template are classified as 'very difficult' to crystallise (26%) and almost 2,500 regions (6%) were predicted to contain at least 3 TM helices. The 3D-SPECS (3D Structural Proteomics Explorer with Crystallisation Scores) website contains crystallisation predictions for the entire human proteome and can be found at http://www.bioinformaticsplus.org/3dspecs. PMID:22354707

  4. Geochemical variability in MORB controlled by concurrent mixing and crystallisation

    NASA Astrophysics Data System (ADS)

    Shorttle, Oliver

    2015-08-01

    The isotopic and elemental diversity in mid-ocean ridge basalts (MORB) traces the history of mantle differentiation, recycling and convective stirring. However, to interpret this record it is critical to account for the magma transport and storage processes modifying the primary geochemical variability of mantle derived melts. Magma mixing during low pressure differentiation is a key petrological process that controls the chemical variability of basalts throughout the global mid-ocean ridge system. Mixing occurs concurrent with crystallisation and must in general be dominant over any assimilatory processes in controlling the chemical evolution of basalts with MgO concentrations >5 wt% MgO. The effect of this mixing is to collapse the diversity of melt compositions leaving the mantle into the narrow range expressed in most mid-ocean ridge settings. In this context magma mixing can be viewed as contaminating the variance structure of primitive mantle melts, which leads to irreversible information loss on the sources and processes involved in melt generation unless primitive, unmixed, liquids and crystal phases are erupted. However, where we can track magma mixing, the homogenisation itself offers the potential to be an important petrological tool, which constrains the storage and transport processes magma experiences during its ascent through the mantle and crust. In the global dataset interrogated here systematic mixing trends are visible up to the length scales of first order ridge segmentation (∼300 km), indicating the possible links between surface tectonics and the record of mantle heterogeneity in basalts. The importance of magma mixing at mid-ocean ridges hints at the need to reevaluate the MORB-ocean island basalt chemical dichotomy, given the poorly understood mixing processes operating during intraplate magma transport from mantle to surface.

  5. Infrared thermography monitoring of the NaCl crystallisation process

    NASA Astrophysics Data System (ADS)

    Vázquez, Patricia; Thomachot-Schneider, Céline; Mouhoubi, Kamel; Fronteau, Gilles; Gommeaux, Maxime; Benavente, David; Barbin, Vincent; Bodnar, Jean-Luc

    2015-07-01

    In this work, we describe the growth of NaCl crystals by evaporating droplets of aqueous solution while monitoring them with infrared thermography. Over the course of the evaporation experiments, variations in the recorded signal were observed and interpreted as being the result of evaporation and crystallisation. In particular, we observed sharp and transient decreases in the thermosignal during the later stages of high-concentration drop evaporation. The number of such events per experiment, referred to as "pop-cold events", varied from 1 to over 100 and had durations from 1 to 15 s. These events are interpreted as a consequence from the top-supplied creeping (TSC) of the solution feeding the growth of efflorescence-like crystals. This phenomenon occurred when the solution was no longer macroscopically visible. In this case, efflorescence-like crystals with a spherulite shape grew around previously formed cubic crystals. Other crystal morphologies were also observed but were likely fed by mass diffusion or bottom-supplied creeping (BSC) and were not associated with "pop-cold events"; these morphologies included the cubic crystals at the centre, ring-shaped at the edge of droplets and fan-shaped crystals. After complete evaporation, an analysis of the numbers and sizes of the different types of crystals was performed using image processing. Clear differences in their sizes and distribution were observed in relation to the salt concentration. Infrared thermography permitted a level of quantification that previously was only possible using other techniques. As example, the intermittent efflorescence growth process was clearly observed and measured for the first time using infrared thermography.

  6. Development of a solvate as an active pharmaceutical ingredient: Developability, crystallisation and isolation challenges

    NASA Astrophysics Data System (ADS)

    Douillet, Julien; Stevenson, Neil; Lee, Mei; Mallet, Franck; Ward, Richard; Aspin, Peter; Dennehy, Daniel Robert; Camus, Laure

    2012-03-01

    The preclinical development of an active pharmaceutical ingredient (API) begins with the selection of a solid state form. A solvate may be selected for development if it is sufficiently stable and if the solvent quantity administered to the patient is lower than the tolerated potential daily exposure (PDE). The selection and process development of a solvate is presented here. The initial crystallisation process gave poor control over the particle size distribution (PSD) and inclusion of additional crystallisation solvent in the crystal lattice. These two API attributes were controlled using micronised seeds and optimising the crystallisation conditions. After filtration, slurry washing with a second solvent was used to replace the high boiling point crystallisation solvent to improve the drying efficiency. The slurry washing was modelled and studied in the laboratory to control the level of unbound crystallisation solvent in the API. The API desolvation during slurry washing was studied by considering thermodynamics, by construction of the ternary phase diagram, and kinetics aspects. This work provides useful approaches and considerations to assess the risks specific to the controlled production of a solvate that are rarely presented in the literature.

  7. Micro-sphere model for strain-induced crystallisation and three-dimensional applications

    NASA Astrophysics Data System (ADS)

    Guilié, J.; Le, Thien-Nga; Le Tallec, P.

    2015-08-01

    Strain-crystallising rubber exhibits interesting properties: for instance, fatigue lifetime is known to be modified by this microstructural evolution which dissipates energy and creates a strong anisotropic reinforcement. We develop herein a micro-sphere 3D constitutive model for such strain-crystallising rubber. It is based on a simplified 1D micromechanical model that we extend with a micro-sphere approach to a full thermodynamically consistent evolutive anisotropic model. A specific numerical strategy is then proposed. The model is assessed on several significative configurations and reproduces the main experimental features while predicting the evolution of anisotropy as a function of the loading history. We finally show that it can also predict the crystallised zone in front of a mode I crack.

  8. Utilisation of adsorption and desorption for simultaneously improving protein crystallisation success rate and crystal quality.

    PubMed

    Guo, Yun-Zhu; Sun, Li-Hua; Oberthuer, Dominik; Zhang, Chen-Yan; Shi, Jian-Yu; Di, Jiang-Lei; Zhang, Bao-Liang; Cao, Hui-Ling; Liu, Yong-Ming; Li, Jian; Wang, Qian; Huang, Huan-Huan; Liu, Jun; Schulz, Jan-Mirco; Zhang, Qiu-Yu; Zhao, Jian-Lin; Betzel, Christian; He, Jian-Hua; Yin, Da-Chuan

    2014-01-01

    High-quality protein crystals of suitable size are an important prerequisite for applying X-ray crystallography to determine the 3-dimensional structure of proteins. However, it is often difficult to obtain protein crystals of appropriate size and quality because nucleation and growth processes can be unsuccessful. Here, we show that by adsorbing proteins onto porous polystyrene-divinylbenzene microspheres (SDB) floating on the surface of the crystallisation solution, a localised high supersaturation region at the surface of the microspheres and a low supersaturation region below the microspheres can coexist in a single solution. The crystals will easily nucleate in the region of high supersaturation, but when they grow to a certain size, they will sediment to the region of low supersaturation and continue to grow. In this way, the probability of crystallisation and crystal quality can be simultaneously increased in a single solution without changing other crystallisation parameters. PMID:25471817

  9. Expression of homologous RND efflux pump genes is dependent upon AcrB expression: implications for efflux and virulence inhibitor design

    PubMed Central

    Blair, Jessica M. A.; Smith, Helen E.; Ricci, Vito; Lawler, Amelia J.; Thompson, Louisa J.; Piddock, Laura J. V.

    2015-01-01

    Objectives Enterobacteriaceae have multiple efflux pumps that confer intrinsic resistance to antibiotics. AcrB mediates clinically relevant multidrug resistance and is required for virulence and biofilm formation, making it an attractive target for the design of inhibitors. The aim of this study was to assess the viability of single transporters as a target for efflux inhibition using Salmonella Typhimurium as the model pathogen. Methods The expression of resistance–nodulation–division (RND) efflux pump genes in response to the inactivation of single or multiple homologues was measured using real-time RT–PCR. Phenotypes of mutants were characterized by measuring antimicrobial susceptibility, dye accumulation and the ability to cause infection in vitro. Results The expression of all RND efflux pump genes was increased when single or multiple acr genes were inactivated, suggesting a feedback mechanism that activates the transcription of homologous efflux pump genes. When two or three acr genes were inactivated, the mutants had further reduced efflux, altered susceptibility to antimicrobials (including increased susceptibility to some, but conversely and counterintuitively, decreased susceptibility to some others) and were more attenuated in the tissue culture model than mutants lacking single pumps were. Conclusions These data indicate that it is critical to understand which pumps an inhibitor is active against and the effect of this on the expression of homologous systems. For some antimicrobials, an inhibitor with activity against multiple pumps will have a greater impact on susceptibility, but an unintended consequence of this may be decreased susceptibility to other drugs, such as aminoglycosides. PMID:25288678

  10. ESA's Research on Growing from Solutions in Microgravity: The Protein Crystallisation Diagnostics Facility and Future Prospects with the Solution Crystallisation Diagnostics Facility

    NASA Astrophysics Data System (ADS)

    Pletser, V.; Mazzoni, S.; Minster, O.; Potthast, L.

    The Protein Crystallization Diagnostics Facility (PCDF) is an instrument developed by Astrium under an ESA contract to observe and study nucleation and crystallisation processes of molecules from solutions in long duration microgravity experiments on board the International Space Station using advanced diagnostics. The experiment PROTEIN, performed with PCDF, aimed at unravelling physical processes and relating the formation of defects in crystals to their growth conditions. This PCDF experiment was performed on the ISS in 2009, integrated in the European Drawer Rack. The PCDF mission was an important milestone and a basis for future experiments. On the occasion of the 2004 Announcement of Opportunity, new proposals in crystallisation and growth have been selected, which targeted a broader range of systems like synthetic zeolites and model colloidal systems. The preparatory activities within the relevant Topical Teams identified a common need for scattering techniques, ranging from traditional state of the art dynamic and static light scattering to sophisticated multi-speckle techniques based on multipixel sensors. This led to the idea of upgrading the process unit of PCDF with a set of diagnostic techniques and interfaces adapted to investigations on zeolites, and to study the possibility of developing a new instrument for studying colloidal structures. The feasibility study of these instruments, called respectively Solution Crystallisation Diagnostics Facility (SCDF) for zeolites and for colloids, has been recently completed, aiming at a consolidated instrument design and development with a plan to upload it in ISS tentatively in 2013. A general overview of present and future activities in aggregation and crystallisation are presented. Starting with the first results from the PCDF mission, the planned future experiments in SCDF will be discussed along with a detailed description of the instrument capabilities.

  11. Timing of Crystallisation of the Lunar Magma Ocean Constrained by the Oldest Zircon

    NASA Technical Reports Server (NTRS)

    Nemchin, A.; Timms, N.; Pidgeon, R.; Geisler, T.; Reddy, S.; Meyer, C.

    2009-01-01

    The presently favoured concept for the early evolution of the Moon involves consolidation of debris from a giant impact of a Mars sized body with Earth forming a primitive Moon with a thick global layer of melt referred to as the Lunar Magma Ocean1 . It is widely accepted that many significant features observed on the Moon today are the result of crystallisation of this magma ocean. However, controversy exists over the precise timing and duration of the crystallisation process. Resolution of this problem depends on the establishment of precise and robust key crystallisation time points. We report a 4417 6 Myr old zircon in lunar breccia sample 72215,195, which provides a precisely determined younger limit for the solidification of the Lunar Magma Ocean. A model based on these data, together with the age of the Moon forming giant impact, defines an exponential time frame for crystallisation and suggests formation of anorthositic crust after about 80-85% of the magma ocean was solidified. In combination with other zircon ages the 4417 +/- 6 Myr age also suggests that the very small (less than a few per cent) residual portion of the magma ocean continued to solidify during the following 300-500 m.y.

  12. Studies of isothermal crystallisation kinetics of sunflower hard stearin-based confectionery fats.

    PubMed

    Bootello, Miguel A; Hartel, Richard W; Levin, Madeline; Martínez-Blanes, Jose M; Real, Concepción; Garcés, Rafael; Martínez-Force, Enrique; Salas, Joaquín J

    2013-08-15

    The crystallisation and polymorphic properties of three sunflower hard stearins (SHSs) and cocoa butter equivalents (CBEs) formulated by blending SHSs and palm mid fraction (PMF) were studied and compared with those from cocoa butter (CB), to explore their possibilities as confectionery fats. The isothermal crystallisation kinetics of these fats were examined by pNMR and DSC at three different temperatures. All samples studied displayed a two-step crystallisation profile that could be fitted to an exponential-Gompertz equation. Stop-and-return DSC studies showed that SHSs and CBEs exhibited different crystallisation mechanisms according to their triacylglycerol composition, with a quick formation of metastable crystals, followed by a polymorphic transition to the more stable β or β' forms. X-ray diffraction (XRD) was used to investigate the polymorphic forms of tempered SHSs and CBEs in the long term. In all cases the resulting fats displayed short spacing patterns associated with β polymorphism. These formulations based on SHSs and PMF met all the requirements to be considered as CBEs; therefore they could be used as an alternative to traditional confectionery fats. PMID:23561095

  13. Image analysis of palm oil crystallisation as observed by hot stage microscopy

    NASA Astrophysics Data System (ADS)

    Harrison, Peter D.; Smith, Kevin W.; Bhaggan, Krishnadath; Stapley, Andrew G. F.

    2016-06-01

    An image processing algorithm previously used to analyse the crystallisation of a pure fat (tripalmitin) has been applied to the crystallisation of a multicomponent natural fat (palm oil). In contrast to tripalmitin, which produced circular crystals with a constant growth rate, palm oil produced speckled crystals caused by the inclusion of entrapped liquid, and growth rates gradually decreased with time. This can be explained by the depletion of crystallisable material in the liquid phase, whereas direct impingement of crystals (the basis of the Avrami equation) was less common. A theoretical analysis combining this depletion with assuming that the growth rate is proportional to the supersaturation of a crystallisable pseudo-component predicted a tanh function variation of radius with time. This was generally able to provide good fits to the growth curves. It was found that growth rate was a relatively mild function of temperature but also varied from crystal to crystal and even between different sides of the same crystal, which may be due to variations in composition within the liquid phase. Nucleation rates were confirmed to vary approximately exponentially with decreasing temperature, resulting in much greater numbers of crystals and a smaller final average crystal size at lower temperatures.

  14. Use of extension-deformation-based crystallisation of silk fibres to differentiate their functions in nature.

    PubMed

    Numata, Keiji; Masunaga, Hiroyasu; Hikima, Takaaki; Sasaki, Sono; Sekiyama, Kazuhide; Takata, Masaki

    2015-08-21

    β-Sheet crystals play an important role in determining the stiffness, strength, and optical properties of silk and in the exhibition of silk-type-specific functions. It is important to elucidate the structural changes that occur during the stretching of silk fibres to understand the functions of different types of fibres. Herein, we elucidate the initial crystallisation behaviour of silk molecules during the stretching of three types of silk fibres using synchrotron radiation X-ray analysis. When spider dragline silk was stretched, it underwent crystallisation and the alignment of the β-sheet crystals became disordered initially but was later recovered. On the other hand, silkworm cocoon silk did not exhibit further crystallisation, whereas capture spiral silk was predominantly amorphous. Structural analyses showed that the crystallisation of silks following extension deformation has a critical effect on their mechanical and optical properties. These findings should aid the production of artificial silk fibres and facilitate the development of silk-inspired functional materials. PMID:26166211

  15. Thermodynamic modelling of a membrane distillation crystallisation process for the treatment of mining wastewater.

    PubMed

    Nathoo, Jeeten; Randall, Dyllon Garth

    2016-01-01

    Membrane distillation (MD) could be applicable in zero liquid discharge applications. This is due to the fact that MD is applicable at high salinity ranges which are generally outside the scope of reverse osmosis (RO) applications, although this requires proper management of precipitating salts to avoid membrane fouling. One way of managing these salts is with MD crystallisation (MDC). This paper focuses on the applicability of MDC for the treatment of mining wastewater by thermodynamically modelling the aqueous chemistry of the process at different temperatures. The paper is based on the typical brine generated from an RO process in the South African coal mining industry and investigates the effect water recovery and operating temperature have on the salts that are predicted to crystallise out, the sequence in which they will crystallise out and purities as a function of the water recovery. The study confirmed the efficacy of using thermodynamic modelling as a tool for investigating and predicting the crystallisation aspects of the MDC process. The key finding from this work was that, for an MDC process, a purer product can be obtained at higher operating temperatures and recoveries because of the inverse solubility of calcium sulphate. PMID:26877038

  16. Cation effects during aggregation and agglomeration of gibbsite particles under synthetic Bayer crystallisation conditions

    NASA Astrophysics Data System (ADS)

    Prestidge, Clive A.; Ametov, Igor

    2000-02-01

    Rheological methods have been used to study the influence of the liquor cation (sodium versus potassium) on the time-dependent gibbsite particle interactions that occur during Bayer process crystallisation. The temperature, supersaturation and seeding levels investigated simulate those experienced in industrial crystallisers. Gibbsite agglomeration was shown to occur by reversible aggregation followed by irreversible cementation. These two sub-steps were individually characterised by careful choice of seed surface area and liquor supersaturation during batch crystallisation. At seed loading levels less than 10% w/w aggregates are rapidly cemented into agglomerates, this is more pronounced in sodium- than potassium-based liquors. These suspensions were Newtonian and the extent of agglomeration correlated with their viscosity. At seed loading levels greater than 20% w/w particle aggregation resulted in extensively time-dependent and non-Newtonian rheology. However, the aggregates did not undergo cementation into agglomerates and no irreversible size enlargement was evident. Yield stress development with time was used to probe the kinetics of aggregation and quantify the particle interaction behaviour. The rate and extent of the particle network formation is more pronounced in sodium rather than potassium-based liquors, supersaturation dependent, alkali concentration dependent, but only weakly temperature dependent. These findings are discussed with respect to the chemical and physical mechanisms of agglomeration in Bayer crystallisation and the role of cation.

  17. Strong Isotope Effects on Melting Dynamics and Ice Crystallisation Processes in Cryo Vitrification Solutions

    PubMed Central

    Kirichek, Oleg; Soper, Alan; Dzyuba, Boris; Callear, Sam; Fuller, Barry

    2015-01-01

    The nucleation and growth of crystalline ice during cooling, and further crystallization processes during re-warming are considered to be key processes determining the success of low temperature storage of biological objects, as used in medical, agricultural and nature conservation applications. To avoid these problems a method, termed vitrification, is being developed to inhibit ice formation by use of high concentration of cryoprotectants and ultra-rapid cooling, but this is only successful across a limited number of biological objects and in small volume applications. This study explores physical processes of ice crystal formation in a model cryoprotective solution used previously in trials on vitrification of complex biological systems, to improve our understanding of the process and identify limiting biophysical factors. Here we present results of neutron scattering experiments which show that even if ice crystal formation has been suppressed during quench cooling, the water molecules, mobilised during warming, can crystallise as detectable ice. The crystallisation happens right after melting of the glass phase formed during quench cooling, whilst the sample is still transiting deep cryogenic temperatures. We also observe strong water isotope effects on ice crystallisation processes in the cryoprotectant mixture. In the neutron scattering experiment with a fully protiated water component, we observe ready crystallisation occurring just after the glass melting transition. On the contrary with a fully deuteriated water component, the process of crystallisation is either completely or substantially supressed. This behaviour might be explained by nuclear quantum effects in water. The strong isotope effect, observed here, may play an important role in development of new cryopreservation strategies. PMID:25815751

  18. Hen egg-white lysozyme crystallisation: protein stacking and structure stability enhanced by a Tellurium(VI)-centred polyoxotungstate.

    PubMed

    Bijelic, Aleksandar; Molitor, Christian; Mauracher, Stephan G; Al-Oweini, Rami; Kortz, Ulrich; Rompel, Annette

    2015-01-19

    As synchrotron radiation becomes more intense, detectors become faster and structure-solving software becomes more elaborate, obtaining single crystals suitable for data collection is now the bottleneck in macromolecular crystallography. Hence, there is a need for novel and advanced crystallisation agents with the ability to crystallise proteins that are otherwise challenging. Here, an Anderson-Evans-type polyoxometalate (POM), specifically Na6 [TeW6 O24 ]⋅22 H2 O (TEW), is employed as a crystallisation additive. Its effects on protein crystallisation are demonstrated with hen egg-white lysozyme (HEWL), which co-crystallises with TEW in the vicinity (or within) the liquid-liquid phase separation (LLPS) region. The X-ray structure (PDB ID: 4PHI) determination revealed that TEW molecules are part of the crystal lattice, thus demonstrating specific binding to HEWL with electrostatic interactions and hydrogen bonds. The negatively charged TEW polyoxotungstate binds to sites with a positive electrostatic potential located between two (or more) symmetry-related protein chains. Thus, TEW facilitates the formation of protein-protein interfaces of otherwise repulsive surfaces, and thereby the realisation of a stable crystal lattice. In addition to retaining the isomorphicity of the protein structure, the anomalous scattering of the POMs was used for macromolecular phasing. The results suggest that hexatungstotellurate(VI) has great potential as a crystallisation additive to promote both protein crystallisation and structure elucidation. PMID:25521080

  19. Mechanism and modelling of aluminium nanoparticle oxidation coupled with crystallisation of amorphous Al2O3 shell

    NASA Astrophysics Data System (ADS)

    Kong, Chengdong; Yu, Dan; Li, Shuiqing; Yao, Qiang

    2016-03-01

    The oxidation of aluminium nanoparticles coupled with crystallisation of amorphous alumina shell is investigated through the thermogravimetric analyser and differential scanning calorimetry (TGA-DSC) and the transmission electron microscope (TEM). The thermogravimetric (TG) curves show stepwise shapes with temperature increase and could be divided into four stages. The reaction at the second stage is complex, including the simultaneous crystallisation of amorphous alumina (am-Al2O3) and Al oxidation. The crystallisation of am-Al2O3 promotes the reaction through generating fast diffusion channels, like micro-cracks and grain boundaries in the oxide shell to accelerate the ionic diffusion. An enhancement factor (freact), which follows a power-law formula with the crystallisation rate, is introduced to quantify the impact of crystallisation on reaction. With heating rate increase, the second stage of TG curves shifts to the high temperature regime and the total weight gain at the second stage decreases slowly. A crystallisation-reaction model is constructed to fit and predict the weight gain after derivation of diffusivities and crystallisation kinetics. Modelling indicates that with heating rate rise, the mass increment at the second stage of TG curves decreases owing to the reduced reaction time, although the reaction is accelerated. The shift of TG curve to higher temperature is due to the polymorphic phase transition. Actually the derived kinetics of the crystallisation of amorphous alumina indicates that the polymorphic phase transformation mechanism works mainly below the heating rate of 3 K s-1. At higher heating rate, the melting of Al takes place firstly and the crystallisation of am-Al2O3 follows to enhance the ionic diffusion. Therefore, when the heating rate is fast during ignition or combustion, the Al nanoparticles undergo both the melting of Al and the polymorphic phase transition of am-Al2O3 to accelerate the reaction.

  20. The Rustenburg Layered Suite (Bushveld Complex) crystallised in less than 1.5 million years

    NASA Astrophysics Data System (ADS)

    Zeh, Armin; Ovtcharova, Maria; Wilson, Allan; Schaltegger, Urs

    2014-05-01

    The timing and crystallisation of the ca. 2.055 Ga old Rustenburg Layered Suite (RLS) of the Bushveld Complex is the subject of ongoing debate. The RLS represents one of the Earth's oldest large igneous provinces, and contains the world's largest reserves of PGE, chromium and vanadium. Previous high-precision U-Pb zircon dating indicated periodic crystallisation over an interval of 5.2 ± 0.79 Ma, with zircon crystallisation events at 2060.5 Ma, below the UG2 chromitite, and at 2055.3 Ma from the Merensky Reef (MR) upwards in the succession (Scoates & Friedman, 2008; Scoates et. al., 2012). Such a prolonged and periodic crystallisation history, however, contradicts field observations and petrological data, which rather require a relatively fast and continuous crystallisation process, periodically interrupted by new magma replenishment (Eales & Cawthorn, 1996; Cawthorn & Walraven, 1998). Here, we present new data from high-precision U-Pb dating, Ti-in-zircon thermometry, and mineral inclusion studies that support this latter interpretation. Our data indicate that zircon crystallised from highly fractionated, silica-saturated intercumulus melts at temperatures between 890 and 700°C most likely continuously from the base of the RLS (Marginal Zone) to the top (Upper Zone), within 0.92 ± 0.57 Ma, between 2055.81 ± 0.20 and 2054.89 ± 0.37 Ma. References Eales, H. V. & Cawthorn, R. G. (1996). The Bushveld Complex, in Layered Intrusions (ed. Cawthorn, R. G.) 181-229 (Elsevier Science, Amsterdam). Cawthorn, R. G. & Walraven, F. (1998). Emplacement and crystallization time for the Bushveld Complex. J. Petrol. 39, 1669-1687. Scoates, J. S. & Friedman, R. M. (2008). Precise age of the platiniferous Merensky Reef, Bushveld Complex, South Africa, by the U-Pb zircon chemical abrasion ID-TIMS technique. Econ. Geol. 103, 465-471. Scoates, J. S., Wall, C. J., Friedman, R. M., VanTongeren, J. A. & Mathez, E. A (2012). Age of the Bushveld Complex. Abstr. Goldschmidt Conference

  1. Approaches to determine the enthalpy of crystallisation, and amorphous content, of lactose from isothermal calorimetric data.

    PubMed

    Dilworth, Sarah E; Buckton, Graham; Gaisford, Simon; Ramos, Rita

    2004-10-13

    Amorphous lactose will crystallise rapidly if its glass transition temperature is reduced below its storage temperature. This is readily achieved by storing samples at ambient temperature and a relative humidity (RH) of greater than 50%. If the sample is monitored in an isothermal microcalorimeter as it crystallises, the heat changes associated with the event can be measured; indeed this is one of the methods used to quantify the amorphous content of powders and formulations. However, variations in the calculation methods used to determine these heat changes have led to discrepancies in the values reported in the literature and frequently make comparison of data from different sources difficult. Data analysis and peak integration software allow the selection and integration of specific areas of complex traces with great reproducibility; this has led to the observation that previously ignored artefacts are in fact of sufficient magnitude to affect calculated enthalpies. In this work a number of integration methodologies have been applied to the analysis of amorphous spray-dried lactose, crystallised under 53 or 75% RH at 25 degrees C. The data allowed the selection of a standard methodology from which reproducible heat changes could be determined. The method was subsequently applied to the analysis of partially amorphous lactose samples (containing 1-100% (w/w) amorphous content) allowing the quantification limit of the technique to be established. It was found that the best approach for obtaining reproducible results was (i) to crystallise under an RH of 53%, because this slowed the crystallisation response allowing better experimental measurement and (ii) to integrate all the events occurring in the ampoule, rather than trying to select only that region corresponding to crystallisation, since it became clear that the processes occurring in the cell overlapped and could not be deconvoluted. The technique was able to detect amorphous contents as low as 1% (w

  2. Computer simulations suggest direct and stable tip to tip interaction between the outer membrane channel TolC and the isolated docking domain of the multidrug RND efflux transporter AcrB.

    PubMed

    Schmidt, Thomas H; Raunest, Martin; Fischer, Nadine; Reith, Dirk; Kandt, Christian

    2016-07-01

    One way by which bacteria achieve antibiotics resistance is preventing drug access to its target molecule for example through an overproduction of multi-drug efflux pumps of the resistance nodulation division (RND) protein super family of which AcrAB-TolC in Escherichia coli is a prominent example. Although representing one of the best studied efflux systems, the question of how AcrB and TolC interact is still unclear as the available experimental data suggest that either both proteins interact in a tip to tip manner or do not interact at all but are instead connected by a hexamer of AcrA molecules. Addressing the question of TolC-AcrB interaction, we performed a series of 100 ns - 1 µs-molecular dynamics simulations of membrane-embedded TolC in presence of the isolated AcrB docking domain (AcrB(DD)). In 5/6 simulations we observe direct TolC-AcrB(DD) interaction that is only stable on the simulated time scale when both proteins engage in a tip to tip manner. At the same time we find TolC opening and closing freely on extracellular side while remaining closed at the inner periplasmic bottleneck region, suggesting that either the simulated time is too short or additional components are required to unlock TolC. PMID:27045078

  3. Use of RNA tertiary interaction modules for the crystallisation of the spliceosomal snRNP core domain.

    PubMed

    Leung, Adelaine K W; Kambach, Christian; Kondo, Yasushi; Kampmann, Martin; Jinek, Martin; Nagai, Kiyoshi

    2010-09-10

    RNA is known to perform diverse roles in the cell, often as ribonucleoprotein (RNP) particles. While the crystal structure of these RNP particles could provide crucial insights into their functions, crystallographic work on RNP complexes is often hampered by difficulties in obtaining well-diffracting crystals. The small nuclear ribonucleoprotein (snRNP) core domain, acting as an assembly nucleus for the maturation of snRNPs, plays a crucial role in the biogenesis of four of the spliceosomal snRNPs. We have succeeded in crystallising the human U4 snRNP core domain containing seven Sm proteins and a truncated U4 snRNA variant. The most critical factor in our success in the crystallisation was the introduction of various tertiary interaction modules into the RNA that could promote crystal packing without altering the core structure. Here, we describe various strategies employed in our crystallisation effort that could be applied to crystallisation of other RNP particles. PMID:20643141

  4. Solvothermal synthesis of perovskites and pyrochlores: crystallisation of functional oxides under mild conditions.

    PubMed

    Modeshia, Deena R; Walton, Richard I

    2010-11-01

    In this critical review we consider the large literature that has accumulated in the past 5-10 years concerning solution-mediated crystallisation of complex oxide materials using hydrothermal, or more generally solvothermal, reaction conditions. The aim is to show how the synthesis of dense, mixed-metal oxide materials, usually prepared using the high temperatures associated with solid-chemistry, is perfectly feasible from solution in one step reactions, typically at temperatures as low as 200 °C, and that important families of oxide materials have now been reported to crystallise using such synthetic approaches. We will focus on two common structures seen in oxide chemistry, ABO(3) perovskites and A(2)B(2)O(6)O' pyrochlores, and include a systematic survey of the variety of chemical elements now included in these two prototypical structure types, from transition metals, in families of materials that include titanates, niobates, manganites and ferrites, to main-group elements in stannates, plumbates and bismuthates. The significant advantages of solution-mediated crystallisation are well illustrated by the recent literature: examples are provided of elegant control of crystal form from the nanometre to the micron length scale to give thin films, anisotropic crystal morphologies, or hierarchical structures of materials with properties desirable for many important contemporary applications. In addition, new metastable materials have been reported, not stable once high temperatures and pressures are applied and hence not amenable using conventional synthesis. We critically discuss the possible control offered by solvothermal synthesis from crystal chemistry to crystal form and how the discovery of new materials may be achieved. Computer simulation, combinatorial synthesis approaches and in situ methods to follow crystallisation will be vital in providing the predictability in synthesis that is needed for rational design of new materials (232 references). PMID

  5. Crystallisation in apatite-mullite glass-ceramics as a function of fluorine content

    NASA Astrophysics Data System (ADS)

    Stanton, Kenneth T.; Hill, Robert G.

    2005-02-01

    Apatite-mullite glass-ceramics are materials prepared by the controlled heat-induced devitrification of glasses of suitable composition and are under investigation for applications in dentistry and orthopaedics. The glasses used here are based on a system with the composition 1.5(5- x)SiO 2·(5- x)Al 2O 3·1.5P 2O 5·(5- x)CaO· xCaF 2. The amount of fluorine in the glasses was varied to investigate the crystallisation behaviour as a function of both fluorine content and temperature. The resultant crystalline phases are fluorapatite [Ca 10(PO 4) 6F 2], mullite [Al 6Si 2O 13] and in some cases, anorthite [CaAl 2Si 2O 8]. Crystal phases were identified using X-ray diffraction (XRD) from both the surface and the bulk of heat-treated monolithic samples and scanning electron microscopy (SEM) was used to image the crystal phase morphologies. Crystallisation characteristics varied widely in terms of apparent nucleation mechanism, crystal phases formed and microstructure. In general, glasses with higher fluorine content devitrified more readily to fluorapatite (FAp) with a higher nucleation density and for glasses with an intermediate to low fluorine content there tended to be an interdependence between FAp and mullite crystallisation. A greater tendency towards anorthite formation, especially at surfaces, was observed for glasses with lower fluorine contents. Furthermore, on decreasing the fluorine content, glasses tended to crystallise by formation of FAp spherulites with increasing diameter and with greater crystal aspect ratio.

  6. Crystallisation of paracetamol (acetaminophen) in the presence of structurally related substances

    NASA Astrophysics Data System (ADS)

    Hendriksen, Barry A.; Grant, David J. W.; Meenan, Paul; Green, Daniel A.

    1998-02-01

    Paracetamol was crystallised from aqueous solutions containing various concentrations of structurally related compounds. Crystal shape was characterised by image analysis and the additive concentration incorporated into the crystals determined by HPLC. The crystal structure of pure acetaminophen displays a hydrogen bonded network, from which is derived a mechanistic interpretation of the abilities of additive molecules to influence crystal growth. This structural approach was used to explain the observed additive uptake, the morphological changes, and the previously reported inhibition of nucleation.

  7. Effect of crystallisation conditions and feedstock morphology on the aerosolization performance of micronised salbutamol sulphate.

    PubMed

    Shariare, M H; de Matas, M; York, P

    2011-08-30

    Salbutamol sulphate (SS) used in dry powder inhalers requires drug particles in the respirable size range of 1-5 μm to achieve a suitable therapeutic effect. The aim of this study was therefore to determine strategies for controlling drug substance characteristics pre and post-crystallisation to facilitate the production of micronised SS with desirable particle attributes for optimal delivery as an inhaled aerosol. SS batches were crystallised using an antisolvent method to produce a range of crystal morphologies. Air jet milling was then used to reduce the size of crystallised SS particles. Starting materials and micronised batches of SS were characterised in the solid state using a range of techniques with subsequent assessment of aerosol properties. Assessment of the aerodynamic characteristics of micronised SS delivered by DPI (without any carrier) indicated that fine particle fraction and emitted dose as a percentage of the total recovered dose were dependent on the quality attributes of the micronised SS, which were directly linked to the degree of imperfections and the morphology of the crystalline feedstock used in micronisation. Aerosolization performance of micronised SS can be optimised by manipulation of feedstock characteristics through crystal engineering and through definition of optimal processing conditions for micronisation. PMID:21683128

  8. Cell-free expression and in meso crystallisation of an integral membrane kinase for structure determination.

    PubMed

    Boland, Coilín; Li, Dianfan; Shah, Syed Tasadaque Ali; Haberstock, Stefan; Dötsch, Volker; Bernhard, Frank; Caffrey, Martin

    2014-12-01

    Membrane proteins are key elements in cell physiology and drug targeting, but getting a high-resolution structure by crystallographic means is still enormously challenging. Novel strategies are in big demand to facilitate the structure determination process that will ultimately hasten the day when sequence information alone can provide a three-dimensional model. Cell-free or in vitro expression enables rapid access to large quantities of high-quality membrane proteins suitable for an array of applications. Despite its impressive efficiency, to date only two membrane proteins produced by the in vitro approach have yielded crystal structures. Here, we have analysed synergies of cell-free expression and crystallisation in lipid mesophases for generating an X-ray structure of the integral membrane enzyme diacylglycerol kinase to 2.28-Å resolution. The quality of cellular and cell-free-expressed kinase samples has been evaluated systematically by comparing (1) spectroscopic properties, (2) purity and oligomer formation, (3) lipid content and (4) functionality. DgkA is the first membrane enzyme crystallised based on cell-free expression. The study provides a basic standard for the crystallisation of cell-free-expressed membrane proteins and the methods detailed here should prove generally useful and contribute to accelerating the pace at which membrane protein structures are solved. PMID:25012698

  9. Cell-free Expression and In Meso Crystallisation of an Integral Membrane Kinase for Structure Determination

    PubMed Central

    Shah, Syed Tasadaque Ali; Haberstock, Stefan; Dötsch, Volker; Bernhard, Frank; Caffrey, Martin

    2014-01-01

    Membrane proteins are key elements in cell physiology and drug targeting, but getting a high-resolution structure by crystallographic means is still enormously challenging. Novel strategies are in big demand to facilitate the structure determination process that will ultimately hasten the day when sequence information alone can provide a 3-dimensional model. Cell-free or in vitro expression enables rapid access to large quantities of high quality membrane proteins suitable for an array of applications. Despite its impressive efficiency, to date only two membrane proteins produced by the in vitro approach have yielded crystal structures. Here, we have analysed synergies of cell-free expression and crystallisation in lipidic mesophases for generating an X-ray structure of the integral membrane enzyme diacylglycerol kinase to 2.28 Å resolution. The quality of cellular and cell-free expressed kinase samples have been evaluated systematically by comparing i) spectroscopic properties, ii) purity and oligomer formation, iii) lipid content and iv) functionality. DgkA is the first membrane enzyme crystallised based on cell-free expression. The study provides a basic standard for the crystallisation of cell-free expressed membrane proteins and the methods detailed here should prove generally useful and contribute to accelerating the pace at which membrane protein structures are solved. PMID:25012698

  10. The influence of physical properties and morphology of crystallised lactose on delivery of salbutamol sulphate from dry powder inhalers.

    PubMed

    Kaialy, Waseem; Martin, Gary P; Larhrib, Hassan; Ticehurst, Martyn D; Kolosionek, Ewa; Nokhodchi, Ali

    2012-01-01

    The aim of this work was to investigate the mechanistic evaluation of physicochemical properties of new engineered lactose on aerosolisation performance of salbutamol sulphate (SS) delivered from dry powder inhaler (DPI). Different crystallised lactose particles were obtained from binary mixtures of butanol:acetone. The sieved fractions (63-90 μm) of crystallised lactose were characterised in terms of size, shape, flowability, true density and aerosolisation performance (using multiple twin stage impinger (MSLI), Aerolizer(®) inhaler device, and salbutamol sulphate as a model drug). Compared to commercial lactose, crystallised lactose particles were less elongated, covered with fine lactose particles, and had a rougher surface morphology. The crystallised lactose powders had a considerably lower bulk and tap density and poorer flow when compared to commercial lactose. Engineered carrier with better flow showed improved drug content homogeneity, reduced amounts of drug "deposited" on the inhaler device and throat, and a smaller drug aerodynamic diameter upon inhalation. Aerodynamic diameter of salbutamol sulphate increased as lactose aerodynamic diameter decreased (linear, R(2)=0.9191) and/or as fine particle lactose content increased (linear, R(2)=0.8653). Improved drug aerosolisation performance in the case of crystallised lactose particles was attributed to lower drug-carrier adhesion forces due to a rougher surface and higher fine particle content. In conclusion, this work proved that using binary combinations of solvents in crystallisation medium is vital in modification of the physicochemical and micromeritic properties of carriers to achieve a desirable aerosolisation performance from DPI formulations. Among all lactose samples, lactose particles crystallised from pure butanol generated the highest overall DPI formulations desirability. PMID:21962946

  11. Diatom-inspired skeletonisation of insulin - Mechanistic insights into crystallisation and extracellular bioactivity.

    PubMed

    Véliz, Diosángeles Soto; Alam, Catharina; Nietzel, Thiago; Wyborski, Rebecca; Rivero-Müller, Adolfo; Alam, Parvez

    2015-09-01

    In this paper, we encage insulin within calcium carbonate by means of a biomineralisation process. We find that both dogbone and crossbone morphologies develop during the crystallisation process. The crystals break down into small nanocrystals after prolonged immersion in phosphate buffer solution, which adhere extracellularly to mammalian cells without causing any observable damage or early cell-death. The mechanisms behind calcium carbonate encaging of single insulin monomers are detailed. This communication elucidates a novel, diatom-inspired approach to the mineral skeletonisation of insulin. PMID:26094146

  12. Coarse-grained modelling of triglyceride crystallisation: a molecular insight into tripalmitin tristearin binary mixtures by molecular dynamics simulations

    NASA Astrophysics Data System (ADS)

    Pizzirusso, Antonio; Brasiello, Antonio; De Nicola, Antonio; Marangoni, Alejandro G.; Milano, Giuseppe

    2015-12-01

    The first simulation study of the crystallisation of a binary mixture of triglycerides using molecular dynamics simulations is reported. Coarse-grained models of tristearin (SSS) and tripalmitin (PPP) molecules have been considered. The models have been preliminarily tested in the crystallisation of pure SSS and PPP systems. Two different quenching procedures have been tested and their performances have been analysed. The structures obtained from the crystallisation procedures show a high orientation order and a high content of molecules in the tuning fork conformation, comparable with the crystalline α phase. The behaviour of melting temperatures for the α phase of the mixture SSS/PPP obtained from the simulations is in qualitative agreement with the behaviour that was experimentally determined.

  13. Epitaxially grown polycrystalline silicon thin-film solar cells on solid-phase crystallised seed layers

    NASA Astrophysics Data System (ADS)

    Li, Wei; Varlamov, Sergey; Xue, Chaowei

    2014-09-01

    This paper presents the fabrication of poly-Si thin film solar cells on glass substrates using seed layer approach. The solid-phase crystallised P-doped seed layer is not only used as the crystalline template for the epitaxial growth but also as the emitter for the solar cell structure. This paper investigates two important factors, surface cleaning and intragrain defects elimination for the seed layer, which can greatly influence the epitaxial grown solar cell performance. Shorter incubation and crystallisation time is observed using a simplified RCA cleaning than the other two wet chemical cleaning methods, indicating a cleaner seed layer surface is achieved. Cross sectional transmission microscope images confirm a crystallographic transferal of information from the simplified RCA cleaned seed layer into the epi-layer. RTA for the SPC seed layer can effectively eliminate the intragrain defects in the seed layer and improve structural quality of both of the seed layer and the epi-layer. Consequently, epitaxial grown poly-Si solar cell on the RTA treated seed layer shows better solar cell efficiency, Voc and Jsc than the one on the seed layer without RTA treatment.

  14. Influence of environment and grinding on the crystallisation mechanism of ZrO2 gel

    NASA Astrophysics Data System (ADS)

    Criado, J. M.; González, M.; Diánez, M. J.; Pérez-Maqueda, L. A.; Málek, Jiri

    2007-05-01

    The influence of grinding and surrounding atmosphere on the thermal transformations of zirconia gel has been studied. The XRD analysis of the products obtained by thermal decomposition of zirconia gel has shown that pure tetragonal phase is obtained if the gel decomposition is carried out under high vacuum or dry inert atmosphere, while monoclinic zirconia results from the decomposition of the zirconia gel under air or inert gas saturated with water vapour. A mechanism for the thermal crystallisation of zirconia gel has been proposed from the study of the variation of the crystal size of the monoclinic and tetragonal zirconia phases formed as a function of the temperature and the surrounding atmosphere. The thermal decomposition of ground zirconia leads to the formation of ZrO2 with a percentage of tetragonal phase closed to 90% irrespectively of the surrounding atmosphere. The stabilisation of the tetragonal phase by grinding seems to be connected with the formation of tetragonal zirconia nuclei that cannot be observed by XRD. The crystallisation enthalpy measurements carried out by DSC support this conclusion.

  15. A zero density change phase change memory material: GeTe-O structural characteristics upon crystallisation

    PubMed Central

    Zhou, Xilin; Dong, Weiling; Zhang, Hao; Simpson, Robert E.

    2015-01-01

    Oxygen-doped germanium telluride phase change materials are proposed for high temperature applications. Up to 8 at.% oxygen is readily incorporated into GeTe, causing an increased crystallisation temperature and activation energy. The rhombohedral structure of the GeTe crystal is preserved in the oxygen doped films. For higher oxygen concentrations the material is found to phase separate into GeO2 and TeO2, which inhibits the technologically useful abrupt change in properties. Increasing the oxygen content in GeTe-O reduces the difference in film thickness and mass density between the amorphous and crystalline states. For oxygen concentrations between 5 and 6 at.%, the amorphous material and the crystalline material have the same density. Above 6 at.% O doping, crystallisation exhibits an anomalous density change, where the volume of the crystalline state is larger than that of the amorphous. The high thermal stability and zero-density change characteristic of Oxygen-incorporated GeTe, is recommended for efficient and low stress phase change memory devices that may operate at elevated temperatures. PMID:26068587

  16. One plate, two plates, a thousand plates. How crystallisation changes with large numbers of samples.

    PubMed

    Newman, Janet

    2011-09-01

    Turning commercial lab automation into a high-throughput centre requires an underlying process, and implementing checks to ensure that the process is working as it should. At the Collaborative Crystallisation Centre (C3), protein samples from local, national and international groups are set up in crystallisation screening and optimisation experiments with two thousand 96 well plates being set up each year. During its five years of operation, the C3 has implemented a series of enabling protocols - from simple 'reality checks' to determine if a screen has evaporated during storage to more sophisticated systems such as a sample labelling and tracking system. The most important - and perhaps surprising - lesson has been how much effort is required to effectively communicate between the centre and its clients, as well as between the centre's staff members. It is easy to confuse the concept of 'high throughput' in any field with the idea of setting up an experiment quickly. Although automation can be used to set up a single experiment more rapidly than can be done by hand, the distinguishing feature of a high throughput technology is the sustainability of the increased rate. PMID:21571072

  17. Inhibition of calcium oxalate crystallisation in vitro by an extract of Bergenia ciliata

    PubMed Central

    Saha, Sarmistha; Verma, Ramtej J.

    2013-01-01

    Objective To evaluate the effectiveness of an extract obtained from the rhizomes of Bergenia ciliata (Saxifragaceae) on the inhibition of calcium oxalate (CaOx) crystallisation in vitro. Materials and methods A hydro-alcoholic extract (30:70, v/v) of rhizomes of B. ciliata was prepared at different concentrations (1–10 mg/mL). The crystallisation of CaOx monohydrate (COM) was induced in a synthetic urine system. The nucleation and aggregation of COM crystals were measured using spectrophotometric methods. The rates of nucleation and aggregation were evaluated by comparing the slope of the turbidity of a control system with that of one exposed to the extract. The results were compared with a parallel study conducted with a marketed poly-herbal combination, Cystone, under identical concentrations. Crystals generated in the urine were also analysed by light microscopy. Statistical differences and percentage inhibitions were calculated and assessed. Results The extract of B. ciliata was significantly more effective in inhibiting the nucleation and aggregation of COM crystals in a dose-dependent manner than was Cystone. Moreover, the extract induced more CaOx dihydrate crystals, with a significant reduction in the number and size of COM crystals. Conclusion An extract of the traditional herb B. ciliata has an excellent inhibitory activity on crystalluria and therefore might be beneficial in dissolving urinary stones. However, further study in animal models of urolithiasis is needed to evaluate its potential anti-urolithiatic activity. PMID:26558080

  18. Over 50% reduction in the formation energy of Co-based Heusler alloy films by two-dimensional crystallisation

    SciTech Connect

    Sagar, James; Fleet, Luke R.; Walsh, Michael; Whear, Oliver; Huminiuc, Teodor; Lari, Leonardo; Boyes, Edward D.; Vick, Andrew; Hirohata, Atsufumi

    2014-07-21

    Crystalline formation of high magnetic-moment thin films through low-temperature annealing processes compatible with current semiconductor technologies is crucial for the development of next generation devices, which can utilise the spin degree of freedom. Utilising in-situ aberration corrected electron microscopy, we report a 235 °C crystallisation process for a Co-based ternary Heusler-alloy film whose initial nucleation is initiated by as few as 27 unit cells. The crystallisation occurs preferentially in the 〈111〉 crystalline directions via a two-dimensional (2D) layer-by-layer growth mode; resulting in grains with [110] surface normal and [111] plane facets. This growth process was found to reduce the crystallisation energy by more than 50% when compared to bulk samples whilst still leading to the growth of highly ordered grains expected to give a high degree of spin-polarisation. Our findings suggest that the 2D layer-by-layer growth minimises the crystallisation energy allowing for the possible implementation of highly spin-polarised alloy films into current chip and memory technologies.

  19. Over 50% reduction in the formation energy of Co-based Heusler alloy films by two-dimensional crystallisation

    NASA Astrophysics Data System (ADS)

    Sagar, James; Fleet, Luke R.; Walsh, Michael; Lari, Leonardo; Boyes, Edward D.; Whear, Oliver; Huminiuc, Teodor; Vick, Andrew; Hirohata, Atsufumi

    2014-07-01

    Crystalline formation of high magnetic-moment thin films through low-temperature annealing processes compatible with current semiconductor technologies is crucial for the development of next generation devices, which can utilise the spin degree of freedom. Utilising in-situ aberration corrected electron microscopy, we report a 235 °C crystallisation process for a Co-based ternary Heusler-alloy film whose initial nucleation is initiated by as few as 27 unit cells. The crystallisation occurs preferentially in the ⟨111⟩ crystalline directions via a two-dimensional (2D) layer-by-layer growth mode; resulting in grains with [110] surface normal and [111] plane facets. This growth process was found to reduce the crystallisation energy by more than 50% when compared to bulk samples whilst still leading to the growth of highly ordered grains expected to give a high degree of spin-polarisation. Our findings suggest that the 2D layer-by-layer growth minimises the crystallisation energy allowing for the possible implementation of highly spin-polarised alloy films into current chip and memory technologies.

  20. Selective preparation of elusive and alternative single component polymorphic solid forms through multi-component crystallisation routes.

    PubMed

    Thomas, Lynne H; Wales, Craig; Wilson, Chick C

    2016-05-31

    A transferable, simple, method for producing previously elusive and novel polymorphic forms of important active pharmaceutical ingredients (APIs; paracetamol (acetaminophen), piroxicam and piracetam) is demonstrated. Nitrogen heterocyclic co-molecules are employed to influence the self-assembly crystallisation process in a multi-component environment. Previously unknown solvates have also been synthesised by this method. PMID:27079688

  1. Crystallisation of alpha-crustacyanin, the lobster carapace astaxanthin-protein: results from EURECA

    NASA Astrophysics Data System (ADS)

    Zagalsky, P. F.; Wright, C. E.; Parsons, M.

    1995-08-01

    Crystallisation of alpha-crustacyanin, the lobster carapace astaxanthin-protein was attempted under microgravity conditions in EURECA satellite using liquid-liquid diffusion with polyethyleneglycol (PEG) as precipitant; in a second reaction chamber phenol and dioxan were used as additives to prevent composite crystal growth. Crystals of alpha-crustacyanin grown under microgravity from PEG were larger than those grown terrestrially in the same apparatus under otherwise identical conditions. On retrieval, the crystals from PEG were shown to be composite and gave a powder diffraction pattern. The second reaction chamber showed leakage on retrieval and had also been subjected to rapid temperature variation during flight. Crystal fragments were nevertheless recovered but showed a powder diffraction pattern. It is concluded, certainly for liquid-liquid diffusion using PEG alone, that, for crustacyanin, although microgravity conditions resulted in an increase in dimensions of crystals, a measurable improvement in molecular ordering was not achieved.

  2. New insights into the early stages of silica-controlled barium carbonate crystallisation

    NASA Astrophysics Data System (ADS)

    Eiblmeier, Josef; Schürmann, Ulrich; Kienle, Lorenz; Gebauer, Denis; Kunz, Werner; Kellermeier, Matthias

    2014-11-01

    Recent work has demonstrated that the dynamic interplay between silica and carbonate during co-precipitation can result in the self-assembly of unusual, highly complex crystal architectures with morphologies and textures resembling those typically displayed by biogenic minerals. These so-called biomorphs were shown to be composed of uniform elongated carbonate nanoparticles that are arranged according to a specific order over mesoscopic scales. In the present study, we have investigated the circumstances leading to the continuous formation and stabilisation of such well-defined nanometric building units in these inorganic systems. For this purpose, in situ potentiometric titration measurements were carried out in order to monitor and quantify the influence of silica on both the nucleation and early growth stages of barium carbonate crystallisation in alkaline media at constant pH. Complementarily, the nature and composition of particles occurring at different times in samples under various conditions were characterised ex situ by means of high-resolution electron microscopy and elemental analysis. The collected data clearly evidence that added silica affects carbonate crystallisation from the very beginning (i.e. already prior to, during, and shortly after nucleation), eventually arresting growth on the nanoscale by cementation of BaCO3 particles within a siliceous matrix. Our findings thus shed light on the fundamental processes driving bottom-up self-organisation in silica-carbonate materials and, for the first time, provide direct experimental proof that silicate species are responsible for the miniaturisation of carbonate crystals during growth of biomorphs, hence confirming previously discussed theoretical models for their formation mechanism.Recent work has demonstrated that the dynamic interplay between silica and carbonate during co-precipitation can result in the self-assembly of unusual, highly complex crystal architectures with morphologies and textures

  3. New insights into the early stages of silica-controlled barium carbonate crystallisation.

    PubMed

    Eiblmeier, Josef; Schürmann, Ulrich; Kienle, Lorenz; Gebauer, Denis; Kunz, Werner; Kellermeier, Matthias

    2014-12-21

    Recent work has demonstrated that the dynamic interplay between silica and carbonate during co-precipitation can result in the self-assembly of unusual, highly complex crystal architectures with morphologies and textures resembling those typically displayed by biogenic minerals. These so-called biomorphs were shown to be composed of uniform elongated carbonate nanoparticles that are arranged according to a specific order over mesoscopic scales. In the present study, we have investigated the circumstances leading to the continuous formation and stabilisation of such well-defined nanometric building units in these inorganic systems. For this purpose, in situ potentiometric titration measurements were carried out in order to monitor and quantify the influence of silica on both the nucleation and early growth stages of barium carbonate crystallisation in alkaline media at constant pH. Complementarily, the nature and composition of particles occurring at different times in samples under various conditions were characterised ex situ by means of high-resolution electron microscopy and elemental analysis. The collected data clearly evidence that added silica affects carbonate crystallisation from the very beginning (i.e. already prior to, during, and shortly after nucleation), eventually arresting growth on the nanoscale by cementation of BaCO3 particles within a siliceous matrix. Our findings thus shed light on the fundamental processes driving bottom-up self-organisation in silica-carbonate materials and, for the first time, provide direct experimental proof that silicate species are responsible for the miniaturisation of carbonate crystals during growth of biomorphs, hence confirming previously discussed theoretical models for their formation mechanism. PMID:25362999

  4. Groundmass crystallisation and cooling rates of lava-like ignimbrites: the Grey's Landing ignimbrite, southern Idaho, USA

    NASA Astrophysics Data System (ADS)

    Ellis, B. S.; Cordonnier, B.; Rowe, M. C.; Szymanowski, D.; Bachmann, O.; Andrews, G. D. M.

    2015-10-01

    Constraining magmatic and eruptive processes is key to understanding how volcanoes operate. However, reconstructing eruptive and pre-eruptive processes requires the ability to see through any post-eruptive modification of the deposit. The well-preserved Grey's Landing ignimbrite from the central Snake River Plain provides an opportunity to systematically investigate the post-eruptive processes occurring through a single deposit sheet. Despite overall compositional homogeneity in both bulk and glass compositions, the Grey's Landing ignimbrite does preserve differences in the abundance of Li in plagioclase crystals which are strongly associated with the host lithology. Li abundances in plagioclase from the quickly cooled upper and basal vitrophyres are typically low (average 5 ppm, n = 262) while plagioclase from the microcrystalline interior of the deposit has higher Li contents (average 33 ppm, n = 773). Given that no other trace elemental parameter in plagioclase varies, we interpret the variability in Li to reflect a post-depositional process. Groundmass crystallisation of a rhyolite like Grey's Landing requires ˜50 % crystallisation of sanidine and variable amounts of a silica-rich phase (quartz, tridymite, cristobalite) and plagioclase to satisfy mass balance. We suggest the low affinity of Li for sanidine causes migration of groundmass Li into plagioclase during crystallisation. Even within the microcrystalline interior of the deposit, the morphology of the groundmass varies. The more marginal, finer-grained regions are dominated by cristobalite as the SiO2-rich phase while tridymite and quartz are additionally found in the more slowly cooled, coarser-grained portions of thick sections of the ignimbrite. Numerical models of cooling and crystallisation tested against field observations indicate that the groundmass crystallisation occurred relatively rapidly following emplacement (a maximum of a few years where the ignimbrite is thickest). These numerical

  5. APPA 2011 Conference Highlights

    ERIC Educational Resources Information Center

    Facilities Manager, 2011

    2011-01-01

    This article presents highlights of APPA conference that was held on July 16-18, 2011. The highlights feature photos of 2011-2012 board of directors, outgoing senior regional representatives to the board, meritorious service award, APPA fellow, president's recognition and gavel exchange, and diamond business partner award.

  6. Research Highlights, 2003

    ERIC Educational Resources Information Center

    ACER Press (Australian Council for Educational Research), 2003

    2003-01-01

    "Research Highlights" is an annual publication documenting developments in the Australian Council for Educational Research's (ACER's) research programs for the previous year. The 2003 edition highlights research on the following themes: (1) Australian students excel in international study; (2) Assessing the moral and ethical outcomes of schooling;…

  7. Highlights of 1978 activities

    NASA Technical Reports Server (NTRS)

    1978-01-01

    General highlights of NASA's activities for 1978 are presented. The highlights are categorized into topics such as space science, space transportation systems, space and terrestrial applications, environment, technology utilization, aeronautics, space research and technology, energy programs, and international. A list of the 1978 launches including: (1) launch date; (2) payload designation; (3) launch vehicle; (4) launch site and (5) mission remarks is also presented.

  8. Highlights from Fermilab

    SciTech Connect

    Parke, Stephen J.; /Fermilab

    2009-12-01

    In these two lectures I will chose some highlights from the Tevatron experiments (CDF/D0) and the Neutrino experiments and then discuss the future direction of physics at Fermilab after the Tevatron collider era.

  9. NSI organization and highlights

    NASA Technical Reports Server (NTRS)

    Rounds, Fred

    1991-01-01

    The agenda of the NASA Science Internet (NSI) Users Working Group is given. The NSI project organization is laid out in view graph format. Also given are NSI highlights which are divided into three areas: administration, engineering, and operations.

  10. Langley test highlights, 1981

    NASA Technical Reports Server (NTRS)

    1982-01-01

    Significant aircraft tests which were performed are highlighted. The broad range of the research and technology activities. The conributions of this work toward maintaining United States leadership in aeronautics and space research are illustrated.

  11. Highlights from Fermilab

    NASA Astrophysics Data System (ADS)

    Oddone, P. J.

    2010-12-01

    DISCUSSION by CHAIRMAN: P.J. ODDONE, Scientific Secretaries: W. Fisher, A. Holzner Note from Publisher: The Slides of the Lecture: "Highlights from Fermilab" can be found at http://www.ccsem.infn.it/issp2007/

  12. Crystallisation kinetics of some archetypal ionic liquids: isothermal and non-isothermal determination of the Avrami exponent.

    PubMed

    Pas, Steven J; Dargusch, Matthew S; MacFarlane, Douglas R

    2011-07-01

    The properties of ionic liquids give rise to applications in diverse technology areas including mechanical engineering, mining, aerospace and defence. The arbitrary physical property that defines an ionic liquid is a melting point below 100 °C, and as such, an understanding of crystallisation phenomena is extremely important. This is the first report dealing with the mechanism of crystallisation in ionic liquids. Assuming crystallisation of the ionic liquids is a thermal or mass diffusion-controlled process, the values of the isothermal Avrami exponent obtained from three different ionic liquids with three different anions and cations all indicate that growth occurs with a decreasing nucleation rate (n=1.8-2.2). For one of the ionic liquids it was possible to avoid crystallisation by fast cooling and then observe a devitrification upon heating through the glass transition. The isothermal Avrami exponent of devitrification suggested growth with an increasing nucleating rate (n=4.1), compared to a decreasing nucleation rate when crystallisation occurs on cooling from the melt (n=2.0). Two non-isothermal methods were employed to determine the Avrami exponent of devitrification. Both non-isothermal Avrami exponents were in agreement with the isothermal case (n=4.0-4.15). The applicability of JMAK theory suggests that the nucleation event in the ionic liquids selected is a random stochastic process in the volume of the material. Agreement between the isothermal and non-isothermal techniques for determining the Avrami exponent of devitrification suggests that the pre-exponential factor and the activation energy are independent of thermal history. The heating rate dependence of the glass transition enabled the calculation of the fragility index, which suggests that the ionic liquid is a "strong" glass former. This suggests that the temperature dependence of the rate constant could be close to Arrhenius, as assumed by JMAK theory. More generally, therefore, it can be

  13. Petrology of the freetown layered complex, Sierra Leone: part II. Magma evolution and crystallisation conditions

    NASA Astrophysics Data System (ADS)

    Chalokwu, C. I.

    2001-04-01

    The Freetown Layered Complex, Sierra Leone, is a 65 km long, 14 km wide and 7 km thick tholeiitic intrusion, which had been intruded in the West African Craton during the Jurassic (˜ 190 Ma) opening of the middle Atlantic Ocean. The complex consists of four zones of rhythmically layered sequences of Pl+Ol+Aug±Tmt-Ol+Opx+Pgt+Ol-Pgt. Cumulus inverted pigeonite first appeared at the bottom of Zone 2 before disappearing in the middle of Zone 3 only to reappear at the top of Zone 4 with cumulus titanomagnetite. Calculated emplacement pressures, based on the compositions of coexisting plagioclase-pyroxene and the CaTs reaction, range from 2.8 to 5.1 kbar. Two-pyroxene geothermometer gives crystallisation temperatures of 972-1305 ± 70°C, which compare favourably with temperatures estimated from O isotope thermometers (1040-1290 ± 60°C) and plagioclase-liquid thermometers (1045-1381°C) applied to the Freetown bulk composition and obtained by geochemical summation for each zone. Fe-Ti oxides have all re-equilibrated during subsolidus cooling of the complex, but yield fO 2 between quartz-fayalite-magnetite and wüstite-magnetite buffers at high pressure. Silica activity, based on the En = Fo + SiO 2 equilibrium, has been calculated for the entire stratigraphic section. Instead of a progressive increase from the bottom to the top of the complex, values of silica activity fluctuate within the zones, with major decreases corresponding to levels of new magma additions or the arrival of cumulus titanomagnetite. Stratigraphic summation of whole rock chemical composition of cumulates for zones 2-4, weighted according to the average density of the zones, indicates the zones were produced by multiple injection of high alumina (18.38-20.47 wt%) low Ti (0.46-0.70 wt%) hypersthene-normative tholeiites with moderately high activities of silica. Numerical simulation using the COMAGMAT computer algorithm indicates zone 4 bulk composition, interpreted as approximating the parental

  14. Cold crystallisation behaviour of water molecules in ionic liquids as a screening method to evaluate biocompatibility of the hydrated ionic liquids.

    PubMed

    Fujita, Kyoko; Nikawa, Yohsuke; Ohno, Hiroyuki

    2013-04-21

    Hydrated ionic liquids, exhibiting cold crystallisation behaviour of water molecules in a certain range of water contents, successfully dissolved cytochrome c maintaining the original spin state of heme. PMID:23486783

  15. NASA Langley Highlights, 1997

    NASA Technical Reports Server (NTRS)

    1998-01-01

    Langley's mission is accomplished by performing innovative research relevant to national needs and Agency goals, transferring technology to users in a timely manner, and providing development support to other United States Government Agencies, industry, other NASA Centers, the educational community, and the local community. This report contains highlights of some of the major accomplishments and applications that have been made by Langley researchers and by our university and industry colleagues during the past year. The highlights illustrate the broad range of research and technology activities carried out by NASA Langley Research Center and the contributions of this work toward maintaining United States' leadership in aeronautics and space research.

  16. In Situ Thermal Characterization of Cooling/Crystallising Lavas During Rheology Measurement.

    NASA Astrophysics Data System (ADS)

    Kolzenburg, S.; Giordano, D.; Cimarelli, C.; Dingwell, D. B.

    2015-12-01

    Transport properties of silicate melts at super-liquidus temperatures are reasonably well understood. Migration and transport of silicate melts in the earth's crust and at its surface generally occur at sub-liquidus temperature regimes where they are subject to non-isothermal and non-equilibrium crystallization. To date, rheological data at sub-liquidus temperatures are scarce. In such dynamic situations heat capacities, latent heats of phase changes, viscous heating, thermal advection and thermal inertia of the apparatus are all potential factors in determining the thermal regime. Yet thermal characterisation of non- equilibrium conditions are absent, hampered by the inconvenience of recording in situ sample temperature during dynamic rheological measurements. Here we present a new experimental setup for in situ sample temperature monitoring in high temperature rheometry. We overcome the limitation of hardwired thermocouples during sample deformation by employing wireless data transmitters directly mounted onto the rotating spindle, immersed in the sample. This adaptation enables in situ, real-time, observations of the thermal regime of crystallising, deforming lava samples under the transient and non-equilibrium crystallization conditions expected in lava flows in nature. We present the apparatus calibration procedure, assess the experimental uncertainty in viscosity measurements and discuss experimental data investigating the dynamic, rheologic and thermal evolution of lavas in both temperature step and continuous cooling experiments.

  17. The potential energy landscape for crystallisation of a Lennard-Jones fluid

    NASA Astrophysics Data System (ADS)

    de Souza, Vanessa K.; Wales, David J.

    2016-07-01

    Crystallisation pathways are explored by direct analysis of the potential energy landscape for a system of Lennard-Jones particles with periodic boundary conditions. A database of minima and transition states linking liquid and crystalline states is constructed using discrete path sampling and the entire potential energy landscape from liquid to crystal is visualised. We demonstrate that there is a strong negative correlation between the number of atoms in the largest crystalline cluster and the potential energy. In common with previous results we find a strong bias towards the growth of FCC rather than HCP clusters, despite a very small potential energy difference. We characterise three types of perfect crystals with very similar energies: pure FCC, pure HCP, and combinations of FCC and HCP layers. There are also many slightly defective crystalline structures. The effect of the simulation box is analysed for a supercell containing 864 atoms. There are low barriers between some of the different crystalline structures via pathways involving sliding layers, and many different defective structures with FCC layers stacked at an angle to the periodic box. Finally, we compare a binary Lennard-Jones system and visualise the potential energy landscape from supercooled liquid to crystal.

  18. Carbon isotope fractionation during experimental crystallisation of diamond from carbonate fluid at mantle conditions

    NASA Astrophysics Data System (ADS)

    Reutsky, Vadim; Borzdov, Yuri; Palyanov, Yuri; Sokol, Alexander; Izokh, Olga

    2015-12-01

    We report first results of a systematic study of carbon isotope fractionation in a carbonate fluid system under mantle PT conditions. The system models a diamond-forming alkaline carbonate fluid using pure sodium oxalate (Na2C2O4) as the starting material, which decomposes to carbonate, CO2 and elementary carbon (graphite and diamond) involving a single source of carbon following the reaction 2Na2C2O4 → 2Na2CO3 + CO2 + C. Near-liquidus behaviour of carbonate was observed at 1300 °C and 6.3 GPa. The experimentally determined isotope fractionation between the components of the system in the temperature range from 1300 to 1700 °C at 6.3 and 7.5 GPa fit the theoretical expectations well. Carbon isotope fractionation associated with diamond crystallisation from the carbonate fluid at 7.5 GPa decreases with an increase in temperature from 2.7 to 1.6 ‰. This trend corresponds to the function ΔCarbonate fluid-Diamond = 7.38 × 106 T-2.

  19. Direct measurement of molecular mobility and crystallisation of amorphous pharmaceuticals using terahertz spectroscopy.

    PubMed

    Sibik, Juraj; Zeitler, J Axel

    2016-05-01

    Despite much effort in the area, no comprehensive understanding of the formation and behaviour of amorphous solids has yet been achieved. This severely limits the industrial application of such materials, including drug delivery where, in principle, amorphous solids have demonstrated their great usefulness in increasing the bioavailability of poorly aqueous soluble active pharmaceutical ingredients. Terahertz time-domain spectroscopy is a relatively novel analytical technique that can be used to measure the fast molecular dynamics of molecules with high accuracy in a non-contact and non-destructive fashion. Over the past decade a number of applications for the characterisation of amorphous drug molecules and formulations have been developed and it has been demonstrated how this technique can be used to determine the onset and strength in molecular mobility that underpins the crystallisation of amorphous drugs. In this review we provide an overview of the history, fundamentals and future perspective of pharmaceutical applications related to the terahertz dynamics of amorphous systems. PMID:26772139

  20. Estimation of the growth kinetics for the cooling crystallisation of paracetamol and ethanol solutions

    NASA Astrophysics Data System (ADS)

    Mitchell, Niall A.; Ó'Ciardhá, Clifford T.; Frawley, Patrick J.

    2011-08-01

    This work details the estimation of the growth kinetics of paracetamol in ethanol solutions for cooling crystallisation processes, by means of isothermal seeded batch experiments. The growth kinetics of paracetamol crystals were evaluated in isolation, with the growth rate assumed to be size independent. Prior knowledge of the Metastable Zone Width (MSZW) was required, so that supersaturation ratios of 1.7-1.1 could be induced in solution without the occurrence of nucleation. The technique involved the utilisation of two in-situ Process Analytical Techniques (PATs), with a Focused Beam Reflectance Measurement (FBRM ®) utilised to ensure that negligible nucleation occurred and an Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR) probe employed for online monitoring of solute concentration. Initial Particle Size Distributions (PSDs) were used in conjunction with desupersaturation profiles to determine the growth rate as a function of temperature and supersaturation. Furthermore, the effects of seed loading and size on the crystal growth rate were investigated. A numerical model, incorporating the population balance equation and the method of moments, was utilised to describe the crystal growth process. Experimental parameters were compared to the model simulation, with the accuracy of the model validated by means of the final product PSDs and solute concentration.

  1. Analysis and statistics of crystallisation success increase by composition modification of protein and precipitant mixing ratio.

    PubMed

    Zhang, Chen-Yan; Mazumdar, Mausumi; Zhu, Dao-Wei; Yin, Da-Chuan; Lin, Sheng-Xiang

    2011-10-01

    The nucleation zone has to be reached for any crystal to grow, and the search for crystallization conditions of new proteins is a trial and error process. Here a convenient screening strategy is studied in detail that varies the volume ratio of protein sample to the reservoir solution in the drop to initiate crystallization that is named "composition modification". It is applied after the first screen and has been studied with twelve proteins. Statistical analysis shows a significant improvement in screening using this strategy. The average improvement of "hits" at different temperatures is between 32 and 42%, for examples, 41.8% ± 14.0% and 35.7% ± 12.4% (± standard deviation) at 288 K and 300 K, respectively. Remarkably, some new crystals were found by composition modification which increased the probability of reaching the nucleation zone to initiate crystallization. This was confirmed by a phase diagram study. It is also demonstrated that composition modification can further increase crystallisation success significantly (1.3 times) after the improvement of "hits" by temperature screening. The trajectories of different composition modifications during vapour diffusion were plotted, further demonstrating that protein crystallizability can be increased by hitting more parts of the nucleation zone. It was also found to facilitate the finding of initial crystals for proteins of low solubility. These proteins gradually become more concentrated during the vapour diffusion process starting from a larger protein solution ratio in the initial mixture. PMID:21592082

  2. Effect of annealing treatment on the crystallisation and leaching of dumped base metal smelter slags.

    PubMed

    Maweja, Kasonde; Mukongo, Tshikele; Mbaya, Richard K; Mochubele, Emela A

    2010-11-15

    Leaching tests of base metals contained in two smelter slags were undertaken in ammonia and nitric acid solutions aiming to recover Co, Cu and Zn. Leaching tests were conducted at 25 and 60°C at pH=0 and 3 in HNO(3) and pH=12 in NH(4)OH media. XRD analysis revealed that the dumped slags were amorphous. Annealing these slags at 1180°C produced crystalline phases comprising diopside, magnetite and fayalite. SEM and EDS analysis revealed that Cu and Pb compounds have concentrated in the magnetite phase, whereas another phase rich in Zn and Cu was located in the diopside matrix. ICP-OES analysis of the pregnant leaching solutions (PLS) showed that 30-60% of Co, Cu and Zn were released from the amorphous slags treated in HNO(3) at pH=0, and lesser in ammonia. However, the contamination by Fe and Pb was higher at pH=0. The contamination of the PLS obtained by leaching of the crystallised slags remained low. The low Fe and Pb contamination was attributed in this case to the chemical stability of the crystalline phases formed upon annealing treatment. The higher solubilisation of metals contained in amorphous slags was attributed to the collapse of silicate structures during nitric acid leaching at pH∼0. PMID:20674164

  3. Recent Highlights from VERITAS

    NASA Astrophysics Data System (ADS)

    Wakely, Scott

    VERITAS, an array of atmospheric Cherenkov TeV gamma-ray telescopes, has been in opera-tion since 2007. We will present some highlights from the first few years of observations, with an emphasis on those results most relevant to galactic cosmic-ray astrophysics.

  4. Collegiate Athletics Highlights.

    ERIC Educational Resources Information Center

    St. John, Eric

    1999-01-01

    Highlights 15 trends/events in black college athletics, including championship coaches, Black Coaches Association, eligibility issues, disclosure of athlete graduation rates, athletics resource allocation, early adoption of professional athlete status, success of the Women's National Basketball Association, lack of black access to certain sports,…

  5. E News: Report highlights

    SciTech Connect

    1995-01-01

    Three technologies are highlighted in this issue: a rooftop ice storage system for small commercial loads; chlorofluorocarbon-free electric chillers and their expected market; and the FlashBake oven, a commercial-sized oven that uses high intensity quartz lamps to cook food quickly. Regular columns on Member News and Work in Progress are included.

  6. Highlights of 1981 activities

    NASA Technical Reports Server (NTRS)

    1981-01-01

    The highlights of NASA's 1981 activities are presented, including the results of the two flights of the space shuttle Columbia and the Voyager 2 encounter with Saturn. Accomplishments in the areas of space transportation operations; space science; aeronautical, energy, and space research and development; as well as space tracking, international activities, and 1981 launch activities are discussed.

  7. NASA highlights, 1986 - 1988

    NASA Technical Reports Server (NTRS)

    1990-01-01

    Highlights of NASA research from 1986 to 1988 are discussed. Topics covered include Space Shuttle flights, understanding the Universe and its origins, understanding the Earth and its environment, air and space transportation, using space to make America more competitive, using space technology an Earth, strengthening America's education in science and technology, the space station, and human exploration of the solar system.

  8. Highlights of 1976 activities

    NASA Technical Reports Server (NTRS)

    Fitzpatrick, M.

    1976-01-01

    Highlights of NASA's 1976 activities are summarized. Sixteen successful launches were made. Two landings of Viking spacecraft on Mars and rollout of the space shuttle orbiter are reviewed. Applications of aerospace science to education, health care, and community services are also discussed.

  9. NASA Langley Highlights, 1998

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Langley's mission is accomplished by performing innovative research relevant to national needs and Agency goals, transferring technology to users in a timely manner, and providing development support to other United States Government Agencies, industry, other NASA Centers, the educational community, and the local community. This report contains highlights of some of the major accomplishments and applications that have been made by Langley researchers and by our university and industry colleagues during the past year. The highlights illustrate the broad range of research and technology activities carried out by NASA Langley Research Center and the contributions of this work toward maintaining United States' leadership in aeronautics and space research. A color electronic version of this report is available at URL http://larcpubs.larc.nasa.gov/randt/1998/.

  10. 1999 Digital Avionics Highlights

    NASA Technical Reports Server (NTRS)

    Polites, Michael E.

    1999-01-01

    This article summarizes the highlights of recent events and developments in guidance, navigation, and control in space, aircraft, and weapons. This article is about 1,200 words long. Information for the article was collected from other NASA Centers, DoD, and industry. All information was previously cleared by the originating organizations. Information for the article was also gathered from Aviation Week and Space Technology, and similar sources.

  11. Splice Variants of Perlucin from Haliotis laevigata Modulate the Crystallisation of CaCO3

    PubMed Central

    Franken, Sebastian; Grunwald, Ingo; Kelm, Sørge

    2014-01-01

    Perlucin is one of the proteins of the organic matrix of nacre (mother of pearl) playing an important role in biomineralisation. This nacreous layer can be predominately found in the mollusc lineages and is most intensively studied as a compound of the shell of the marine Australian abalone Haliotis laevigata. A more detailed analysis of Perlucin will elucidate some of the still unknown processes in the complex interplay of the organic/inorganic compounds involved in the formation of nacre as a very interesting composite material not only from a life science-based point of view. Within this study we discovered three unknown Perlucin splice variants of the Australian abalone H. laevigata. The amplified cDNAs vary from 562 to 815 base pairs and the resulting translation products differ predominantly in the absence or presence of a varying number of a 10 mer peptide C-terminal repeat. The splice variants could further be confirmed by matrix-assisted laser desorption ionisation time of flight mass spectrometry (MALDI-ToF MS) analysis as endogenous Perlucin, purified from decalcified abalone shell. Interestingly, we observed that the different variants expressed as maltose-binding protein (MBP) fusion proteins in E. coli showed strong differences in their influence on precipitating CaCO3 and that these differences might be due to a splice variant-specific formation of large protein aggregates influenced by the number of the 10 mer peptide repeats. Our results are evidence for a more complex situation with respect to Perlucin functional regulation by demonstrating that Perlucin splice variants modulate the crystallisation of calcium carbonate. The identification of differentially behaving Perlucin variants may open a completely new perspective for the field of nacre biomineralisation. PMID:24824517

  12. Cloning, expression and crystallisation of SGT1 co-chaperone protein from Glaciozyma antarctica

    NASA Astrophysics Data System (ADS)

    Yusof, Nur Athirah; Bakar, Farah Diba Abu; Beddoe, Travis; Murad, Abdul Munir Abdul

    2013-11-01

    Studies on psycrophiles are now in the limelight of today's post genomic era as they fascinate the research and development industries. The discovery from Glaciozyma antarctica, an extreme cold adapted yeast from Antarctica shows promising future to provide cost effective natural sustainable energy and create wider understanding of the property that permits this organisms to adapt to extreme temperature downshift. In plants and yeast, studies show the interaction between SGT1 and HSP90 are essential for disease resistance and heat stress by activating a number of resistance proteins. Here we report for the first time cloning, expression and crystallization of the recombinant SGT1 protein of G. antarctica (rGa_SGT1), a highly conserved eukaryotic protein that interacts with the molecular chaperones HSP90 (heat shock protein 90) apparently associated in a role of co-chaperone that may play important role in cold adaptation. The sequence analysis of rGa_SGT1 revealed the presence of all the characteristic features of SGT1 protein. In this study, we present the outlines and results of protein structural study of G. antarctica SGT1 protein. We validate this approach by starting with cloning the target insert into Ligation Independent Cloning system proceeded with expression using E. coli system, and crystallisation of the target rGA_SGT1 protein. The work is still on going with the target subunit of the complex proteins yielded crystals. These results, still ongoing, open a platform for better understanding of the uniqueness of this crucial molecular machine function in cold adaptation.

  13. Splice variants of perlucin from Haliotis laevigata modulate the crystallisation of CaCO3.

    PubMed

    Dodenhof, Tanja; Dietz, Frank; Franken, Sebastian; Grunwald, Ingo; Kelm, Sørge

    2014-01-01

    Perlucin is one of the proteins of the organic matrix of nacre (mother of pearl) playing an important role in biomineralisation. This nacreous layer can be predominately found in the mollusc lineages and is most intensively studied as a compound of the shell of the marine Australian abalone Haliotis laevigata. A more detailed analysis of Perlucin will elucidate some of the still unknown processes in the complex interplay of the organic/inorganic compounds involved in the formation of nacre as a very interesting composite material not only from a life science-based point of view. Within this study we discovered three unknown Perlucin splice variants of the Australian abalone H. laevigata. The amplified cDNAs vary from 562 to 815 base pairs and the resulting translation products differ predominantly in the absence or presence of a varying number of a 10 mer peptide C-terminal repeat. The splice variants could further be confirmed by matrix-assisted laser desorption ionisation time of flight mass spectrometry (MALDI-ToF MS) analysis as endogenous Perlucin, purified from decalcified abalone shell. Interestingly, we observed that the different variants expressed as maltose-binding protein (MBP) fusion proteins in E. coli showed strong differences in their influence on precipitating CaCO3 and that these differences might be due to a splice variant-specific formation of large protein aggregates influenced by the number of the 10 mer peptide repeats. Our results are evidence for a more complex situation with respect to Perlucin functional regulation by demonstrating that Perlucin splice variants modulate the crystallisation of calcium carbonate. The identification of differentially behaving Perlucin variants may open a completely new perspective for the field of nacre biomineralisation. PMID:24824517

  14. Laser crystallisation during pulsed laser deposition of barium titanate thin films at low temperatures

    NASA Astrophysics Data System (ADS)

    Gottmann, J.; Vosseler, B.; Kreutz, E. W.

    2002-09-01

    Using a high dielectric material as substitute for SiO xN y in dielectric film capacitors of dynamic memories (DRAM) allows a significantly higher integration density and a reduction of the die size, even with planar capacitors. BaTiO 3 is such a material. A dielectric constant of ɛr>1000 has been achieved in thin films, made by pulsed laser deposition (PLD). For applications in microelectronic memories it is necessary to produce crystalline, defect-free and oriented BaTiO 3 thin films at substrate temperatures, TS<450 °C. Sintered targets of BaTiO 3 are ablated by KrF excimer laser radiation. The processing gas atmosphere consists of O 2 at pressures of 0.1-50 Pa. The substrate is resitively heated to 360-440 °C and annealed after or during PLD on Pt/Ti/Si multilayer substrates using KrF excimer laser radiation with fluences up to 120 mJ/cm 2. The temperature distribution in the BaTiO 3/Pt/Ti/Si multilayers during laser annealing is dynamically modelled and related to the resulting crystal quality and the dielectric properties of the films. With PLD a minimum substrate temperature of 500 °C is necessary to deposit crystalline BaTiO 3 films. Using in situ laser crystallisation crystalline BaTiO 3 films can be deposited at substrate temperatures of TS=360-440 °C showing a dielectric constant of up to ɛr=1200. The ferroelectric and dielectric properties of the films are determined by C- V and P- V impedance measurements and correlated to the chemical and structural properties, as determined by X-ray photoemission spectroscopy, X-ray diffraction, micro Raman spectroscopy and scanning electron microscopy.

  15. Antisolvent crystallisation is a potential technique to prepare engineered lactose with promising aerosolisation properties: effect of saturation degree.

    PubMed

    Kaialy, Waseem; Nokhodchi, Ali

    2012-11-01

    Engineered lactose particles were prepared by anti-solvent crystallisation technique using lactose solutions with different saturation degrees. In comparison to commercial lactose, engineered lactose particles exhibited less elongated and more irregular shape (large aggregates composed of smaller sub-units), rougher surface texture, higher specific surface area, and different anomer form. Engineered lactose powders demonstrated smaller bulk density, smaller tap density, and higher porosity than commercial lactose powder. Dry powder inhaler (DPI) formulations containing engineered lactose and salbutamol sulphate as a model drug demonstrated improved drug content homogeneity and higher amounts of drug delivered to lower airway regions. Higher fine particle fraction of drug was obtained in the case of lactose powders with higher porosity, higher specific surface area and higher fine particle content (<5 μm). The results indicated that the higher the saturation degree of lactose solution used during crystallisation the smaller the specific surface area, the higher the amorphous lactose content, and the higher the β-lactose content of engineered lactose particles. Also, lactose powders obtained from lactose solution with higher degree of saturation showed higher bulk and tap densities and smaller porosity. Engineered lactose powders crystallized from lower saturation degree (20% and 30% w/v) deposited higher amounts of drug on lower airway regions. In conclusion, this study demonstrated that it is possible to prepare engineered lactose particles with favourable properties (e.g. higher fine particle fraction and better drug content homogeneity) for DPI formulations by using lactose solutions with lower degree of saturation during crystallisation process. PMID:22884837

  16. Investigation of the hydrothermal crystallisation of the perovskite solid solution NaCe{sub 1−x}La{sub x}Ti{sub 2}O{sub 6} and its defect chemistry

    SciTech Connect

    Harunsani, Mohammad H.; Woodward, David I.; Peel, Martin D.; Ashbrook, Sharon E.; Walton, Richard I.

    2013-11-15

    Perovskites of nominal composition NaCe{sub 1−x}La{sub x}Ti{sub 2}O{sub 6} (0≤x≤1) crystallise directly under hydrothermal conditions at 240 °C. Raman spectroscopy shows distortion from the ideal cubic structure and Rietveld analysis of powder X-ray and neutron diffraction reveals that the materials represent a continuous series in rhombohedral space group R3-bar c. Ce L{sub III}-edge X-ray absorption near edge structure spectroscopy shows that while the majority of cerium is present as Ce{sup 3+} there is evidence for Ce{sup 4+}. The paramagnetic Ce{sup 3+} affects the chemical shift and line width of {sup 23}Na MAS NMR spectra, which also show with no evidence for A-site ordering. {sup 2}H MAS NMR of samples prepared in D{sub 2}O shows the inclusion of deuterium, which IR spectroscopy shows is most likely to be as D{sub 2}O. The deuterium content is highest for the cerium-rich materials, consistent with oxidation of some cerium to Ce{sup 4+} to provide charge balance of A-site water. - Graphical abstract: A multi-element A-site perovskite crystallises directly from aqueous, basic solutions at 240 °C; while the paramagnetic effect of Ce{sup 3+} on the {sup 23}Na NMR shows a homogeneous solid-solution, the incorporation of A-site water is also found from {sup 2}H NMR and IR, with oxidation of some cerium to charge balance proved by XANES spectroscopy. Display Omitted - Highlights: • Direct hydrothermal synthesis allows crystallisation of a perovskite solid-solution. • XANES spectroscopy shows some oxidation of Ce{sup 3+} to Ce{sup 4+}. • The paramagnetism of Ce{sup 3+} shifts and broadens the {sup 23}Na solid-state NMR. • The perovskite materials incorporate water as an A-site defect.

  17. Voyager: Neptune Encounter Highlights

    NASA Technical Reports Server (NTRS)

    1989-01-01

    Voyager encounter data are presented in computer animation (CA) and real (R) animation. The highlights include a view of 2 full rotations of Neptune. It shows spacecraft trajectory 'diving' over Neptune and intercepting Triton's orbit, depicting radiation and occulation zones. Also shown are a renegade orbit of Triton and Voyager's encounter with Neptune's Magnetopause. A model of the spacecraft's complex maneuvers during close encounters of Neptune and Triton is presented. A view from Earth of Neptune's occulation experiment is is shown as well as a recreation of Voyager's final pass. There is detail of Voyager's Image Compensation technique which produces Voyager images. Eighteen images were produced on June 22 - 23, 1989, from 57 million miles away. A 68 day sequence which provides a stroboscopic view - colorization approximates what is seen by the human eye. Real time images recorded live from Voyager on 8/24/89 are presented. Photoclinometry produced the topography of Triton. Three images are used to create a sequence of Neptune's rings. The globe of Neptune and 2 views of the south pole are shown as well as Neptune rotating. The rotation of a scooter is frozen in images showing differential motion. There is a view of rotation of the Great Dark Spot about its own axis. Photoclinometry provides a 3-dimensional perspective using a color mosaic of Triton images. The globe is used to indicate the orientation of Neptune's crescent. The east and west plumes on Triton are shown.

  18. 1999 NCCS Highlights

    NASA Technical Reports Server (NTRS)

    Bennett, Jerome (Technical Monitor)

    2002-01-01

    The NASA Center for Computational Sciences (NCCS) is a high-performance scientific computing facility operated, maintained and managed by the Earth and Space Data Computing Division (ESDCD) of NASA Goddard Space Flight Center's (GSFC) Earth Sciences Directorate. The mission of the NCCS is to advance leading-edge science by providing the best people, computers, and data storage systems to NASA's Earth and space sciences programs and those of other U.S. Government agencies, universities, and private institutions. Among the many computationally demanding Earth science research efforts supported by the NCCS in Fiscal Year 1999 (FY99) are the NASA Seasonal-to-Interannual Prediction Project, the NASA Search and Rescue Mission, Earth gravitational model development efforts, the National Weather Service's North American Observing System program, Data Assimilation Office studies, a NASA-sponsored project at the Center for Ocean-Land-Atmosphere Studies, a NASA-sponsored microgravity project conducted by researchers at the City University of New York and the University of Pennsylvania, the completion of a satellite-derived global climate data set, simulations of a new geodynamo model, and studies of Earth's torque. This document presents highlights of these research efforts and an overview of the NCCS, its facilities, and its people.

  19. FY 1986 budget highlights

    SciTech Connect

    Not Available

    1985-02-01

    The FY 1986 budget request for DOE supports the energy, general science and defense missions of the Department in a comprehensive manner, while being responsive to the President's directive to all Federal agencies to freeze or reduce Government spending wherever possible to reduce the Federal deficit. The discussion displays the budget in a format designed to emphasize the varied activities of DOE. ''Research and Development'' describes the nature of the scientific and technical effort which underlies the Department's programs in a number of areas, such as energy, general science, and weapons research, which previously appeared in three distinct sections of our budget presentation. ''Defense Production and Support'' highlights a significant element of our defense activities which have production, whether of weapons or materials, as a common thread. ''Waste Activities'' combines programs from the civilian and defense areas to bring attention to a major effort of DOE ''Business Enterprises'' focuses attention on the fact that a number of the Department's activities are operated like businesses, marketing products and generating revenues. ''Grants and Other Energy Functions'' is how we group non-research and development grant programs and such essential activities as energy information and regulation. Finally, ''Department Management'' includes the various ''overhead'' organizations which keep the Department functioning at headquarters and in the field.

  20. STS-70 mission highlights

    NASA Astrophysics Data System (ADS)

    1995-09-01

    The highlights of the STS-70 mission are presented in this video. The flight crew consisted of Cmdr. John Hendricks, Pilot Kevin Kregel, Flight Engineer Nancy Curie, and Mission Specialists Dr. Don Thomas and Dr. Mary Ellen Weber. The mission's primary objective was the deployment of the 7th Tracking Data and Relay Satellite (TDRS), which will provide a communication, tracking, telemetry, data acquisition, and command services space-based network system essential to low Earth orbital spacecraft. Secondary mission objectives included activating and studying the Physiological and Anatomical Rodent Experiment/National Institutes of Health-Rodents (PARE/NIH-R), The Bioreactor Demonstration System (BDS), the Commercial Protein Crystal Growth (CPCG) studies, the Space Tissue Loss/National Institutes of Health-Cells (STL/NIH-C) experiment, the Biological Research in Canisters (BRIC) experiment, Shuttle Amateur Radio Experiment-2 (SAREX-2), the Visual Function Tester-4 (VFT-4), the Hand-Held, Earth Oriented, Real-Time, Cooperative, User-Friendly, Location-Targeting and Environmental System (HERCULES), the Microcapsules in Space-B (MIS-B) experiment, the Windows Experiment (WINDEX), the Radiation Monitoring Equipment-3 (RME-3), and the Military Applications of Ship Tracks (MAST) experiment. There was an in-orbit dedication ceremony by the spacecrew and the newly Integrated Mission Control Center to commemorate the Center's integration. The STS-70 mission was the first mission monitored by this new control center. Earth views included the Earth's atmosphere, a sunrise over the Earth's horizon, several views of various land masses, some B/W lightning shots, some cloud cover, and a tropical storm.

  1. Highlights of Astronomy

    NASA Astrophysics Data System (ADS)

    van der Hucht, Karel

    2008-02-01

    Preface Karel A. van der Hucht; Part I. Invited Discourses: Part II. Joint Discussions: 1. Particle acceleration - from Solar System to AGN Marian Karlicky and John C. Brown; 2. Pulsar emission and related phenomena Werner Becker, Janusz A. Gil and Bronislaw Rudak; 3. Solar activity regions and magnetic structure Debi Prasad Choudhary and Michal Sobotka; 4. The ultraviolet universe: Stars from birth to death Ana I. Gomez de Castro and Martin A. Barstow; 5. Calibrating the top of the stellar M-L relationship Claus Leitherer, Anthony F. J. Moat and Joachim Puls; 6. Neutron stars and black holes in star clusters Frederic A. Rasio; 7. The Universe at z > 6 Daniel Schaerer and Andrea Ferrara; 8. Solar and stellar activity cycles Klaus G. Strassmeier and Alexander Kosovichev; 9. Supernovae: One millennium after SN 1006 P. Frank Winkler, Wolfgang Hillebrandt and Brian P. Schmidt; 10. Progress in planetary exploration missions Guy J. Consolmagno; 11. Pre-solar grains as astrophysical tools Anja C. Andersen and John C. Lattanzio; 12. Long wavelength astrophysics T. Joseph W. Lazio and Namir E. Kassim; 13. Exploiting large surveys for galactic astronomy Christopher J. Corbally, Coryn A. L. Bailer-Jones, Sunetra Giridhar and Thomas H. Lloyd Evans; 14. Modeling dense stellar systems Alison I. Sills, Ladislav Subr and Simon F. Portegies Zwart; 15. New cosmology results from the Spitzer Space Telescope George Helou and David T. Frayer; 16. Nomenclature, precession and new models in fundamental astronomy Nicole Capitaine, Jan Vondrak & James L. Hilton; 17. Highlights of recent progress in seismology of the Sun and Sun-like stars John W. Leibacher and Michael J. Thompson; Part III. Special Sessions: SpS 1. Large astronomical facilities of the next decade Gerard F. Gilmore and Richard T. Schilizzi; SpS 2. Innovation in teaching and learning astronomy methods Rosa M. Ros and Jay M. Pasachoff; SpS 3. The Virtual Observatory in action: New science, new technology and next

  2. Extreme chemical conditions of crystallisation of Umbrian Melilitolites and wealth of rare, late stage/hydrothermal minerals

    NASA Astrophysics Data System (ADS)

    Stoppa, F.; Schiazza, M.

    2014-12-01

    Melilitolites of the Umbria Latium Ultra-alkaline District display a complete crystallisation sequence of peculiar, late-stage mineral phases and hydrothermal/cement minerals, analogous to fractionated mineral associations from the Kola Peninsula. This paper summarises 20 years of research which has resulted in the identification of a large number of mineral species, some very rare or completely new and some not yet classified. The progressive increasing alkalinity of the residual liquid allowed the formation of Zr-Ti phases and further delhayelitemacdonaldite mineral crystallisation in the groundmass. The presence of leucite and kalsilite in the igneous assemblage is unusual and gives a kamafugitic nature to the rocks. Passage to non-igneous temperatures (T<600 °C) is marked by the metastable reaction and formation of a rare and complex zeolite association (T<300 °C). Circulation of low-temperature (T<100 °C) K-Ca-Ba-CO2-SO2-fluids led to the precipitation of sulphates and hydrated and/or hydroxylated silicate-sulphate-carbonates. As a whole, this mineral assemblage can be considered typical of ultra-alkaline carbonatitic rocks.

  3. Estimation of the nucleation kinetics for the anti-solvent crystallisation of paracetamol in methanol/water solutions

    NASA Astrophysics Data System (ADS)

    Ó'Ciardhá, Clifford T.; Frawley, Patrick J.; Mitchell, Niall A.

    2011-08-01

    In this work the primary nucleation kinetics have been estimated for the anti-solvent crystallisation of paracetamol in methanol-water solutions from metastable zone widths (MSZW) and induction times at 25 °C. Laser back-scattering via a focused beam reflectance Measurement (FBRM ®) is utilised to detect the onset of nucleation. The theoretical approach of Kubota was employed to estimate the nucleation kinetics, which accounts for the sensitivity of the nucleation detection technique. This approach is expanded in this work to analyse the induction time for an anti-solvent crystallisation process. Solvent composition is known to have a significant impact on the measured induction times and MSZW. The induction time in this paper was measured from 40% to 70% mass water and the MSZW is measured from 40% to 60% mass water. The primary focus of the paper was to gauge the extent of how solvent composition affects nucleation kinetics so that this effect may be incorporated into a population balance model. Furthermore, the effects of solvent composition on the estimated nucleation rates are investigated. The primary nucleation rates were found to decrease with dynamic solvent composition, with the extent of their reduction linked to the gradient of the solubility curve. Finally, both MSZW and induction time methods have been found to produce similar estimates for the nucleation parameters.

  4. ESO Highlights in 2008

    NASA Astrophysics Data System (ADS)

    2009-01-01

    As is now the tradition, the European Southern Observatory looks back at the exciting moments of last year. 2008 was in several aspects an exceptionally good year. Over the year, ESO's telescopes provided data for more than 700 scientific publications in refereed journals, making ESO the most productive ground-based observatory in the world. ESO PR Highlights 2008 ESO PR Photo 01a/09 The image above is a clickable map. These are only some of the press releases issued by ESO in 2008. For a full listing, please go to ESO 2008 page. Austria signed the agreement to join the other 13 ESO member states (ESO 11/08 and 20/08), while the year marked the 10th anniversary of first light for ESO's "perfect science machine", the Very Large Telescope (ESO 16/08 and 17/08). The ALMA project, for which ESO is the European partner, had a major milestone in December, as the observatory was equipped with its first antenna (ESO 49/08). Also the Atacama Pathfinder Experiment (APEX) telescope impressed this year with some very impressive and publicly visible results. Highlights came in many fields: Astronomers for instance used the Very Large Telescope (VLT) to discover and image a probable giant planet long sought around the star Beta Pictoris (ESO 42/08). This is now the eighth extrasolar planet to have been imaged since the VLT imaged the first extrasolar planet in 2004 (three of eight were imaged with VLT). The VLT also enabled three students to confirm the nature of a unique planet (ESO 45/08). This extraordinary find, which turned up during their research project, is a planet about five times as massive as Jupiter. This is the first planet discovered orbiting a fast-rotating hot star. The world's foremost planet-hunting instrument, HARPS, located at ESO's La Silla observatory, scored a new first, finding a system of three super-Earths around a star (ESO 19/08). Based on the complete HARPS sample, astronomers now think that one Sun-like star out of three harbours short orbit, low

  5. ESO Highlights in 2008

    NASA Astrophysics Data System (ADS)

    2009-01-01

    As is now the tradition, the European Southern Observatory looks back at the exciting moments of last year. 2008 was in several aspects an exceptionally good year. Over the year, ESO's telescopes provided data for more than 700 scientific publications in refereed journals, making ESO the most productive ground-based observatory in the world. ESO PR Highlights 2008 ESO PR Photo 01a/09 The image above is a clickable map. These are only some of the press releases issued by ESO in 2008. For a full listing, please go to ESO 2008 page. Austria signed the agreement to join the other 13 ESO member states (ESO 11/08 and 20/08), while the year marked the 10th anniversary of first light for ESO's "perfect science machine", the Very Large Telescope (ESO 16/08 and 17/08). The ALMA project, for which ESO is the European partner, had a major milestone in December, as the observatory was equipped with its first antenna (ESO 49/08). Also the Atacama Pathfinder Experiment (APEX) telescope impressed this year with some very impressive and publicly visible results. Highlights came in many fields: Astronomers for instance used the Very Large Telescope (VLT) to discover and image a probable giant planet long sought around the star Beta Pictoris (ESO 42/08). This is now the eighth extrasolar planet to have been imaged since the VLT imaged the first extrasolar planet in 2004 (three of eight were imaged with VLT). The VLT also enabled three students to confirm the nature of a unique planet (ESO 45/08). This extraordinary find, which turned up during their research project, is a planet about five times as massive as Jupiter. This is the first planet discovered orbiting a fast-rotating hot star. The world's foremost planet-hunting instrument, HARPS, located at ESO's La Silla observatory, scored a new first, finding a system of three super-Earths around a star (ESO 19/08). Based on the complete HARPS sample, astronomers now think that one Sun-like star out of three harbours short orbit, low

  6. Electrochemical effects of magmatic crystallisation: cyclic units of the Bushveld Igneous Complex

    NASA Astrophysics Data System (ADS)

    Veksler, Ilya V.; Reid, David L.; Dulski, Peter; Keiding, Jakob K.; Trumbull, Robert B.

    2013-04-01

    The Upper Critical Zone (UCZ) of the Bushveld Igneous Complex displays spectacular layering in the form of cyclic units comprising a basal chromitite layer overlain by a sequence of silicate cumulates in the order, from the bottom to the top, pyroxentite-norite-anorthosite. Electron microprobe and laser ablation ICP-MS analyses of chromite and silicate cumulate minerals in the cyclic units between the UG2 chromitite and the Merensky reef revealed variations in major and trace element compositions that are difficult to reconcile with existing models of cumulate mineral-melt evolution. The anomalies in mineral chemistry are best developed at sharp contacts of chromitites with adjacent anorthosite and pyroxenitic cumulates. At the contacts, major element characteristics of chromite composition change abruptly from high and stable Mg/(Mg+Fe2+) and Fe2+/Fe3+ typical for cumulus chromitites to variable and generally low values in chromite crystals disseminated in silicate cumulates. Chromites from different types of cumulates also differ in Sc, V, Ni and Zn contents. The abrupt changes in chromite composition mark the contacts regardless of the thickness of the chromitite layer and estimated mass proportions of chromite to intercumulus liquid. Chemical variations, which defy a simple explanation, are also observed in plagioclase. In addition to previously revealed inconsistency between chemical trends of cumulus plagioclase and orthopyroxene in the UCZ cyclic units our study demonstrates that intercumulus, poikilitic plagioclase cementing chromitite layers has anomalously low Li, K, Rb concentrations and K/La values. Summarising previous studies and the new trace element data we propose a model of post-cumulus re-crystallisation leading to consolidation of a modally layered crystal-liquid mush into a sequence of nearly monomineral layers of chromitites, pyroxenites and anorthosites, which defines the cyclic units. The crucial element of the model is the establishment of

  7. Copper stable isotopes as tracers of metal-sulphide segregation and fractional crystallisation processes on iron meteorite parent bodies

    NASA Astrophysics Data System (ADS)

    Williams, Helen M.; Archer, Corey

    2011-06-01

    lowest Δ 65Cu M-FeS values, whereas the converse is observed in the irons with large values D Cu that deviate most from Cu concentration equilibrium. The magnitudes of Cu and Fe isotope fractionation between metal and FeS in the most equilibrated samples are similar: 0.25 and 0.32‰/amu, respectively. As proposed in an earlier study ( Williams et al., 2006) the range in Δ 57Fe M-FeS values can be explained by incomplete Fe isotope equilibrium between metal and sulphide during cooling, where the most rapidly-cooled samples are furthest from isotopic equilibrium and display the smallest Δ 57Fe M-FeS and largest D Cu values. The range in Δ 65Cu M-FeS, however, reflects the combined effects of partial isotopic equilibrium overprinting an initial kinetic signature produced by the diffusion of Cu from metal into exsolving sulphides and the faster diffusion of the lighter isotope. In this scenario, newly-exsolved sulphides initially have low Cu contents (i.e. high D Cu) and extremely light δ 65Cu FeS values; with progressive equilibrium and fractional crystallisation the Cu contents of the sulphides increase as their isotopic composition becomes less extreme and closer to the metal value. The correlation between Δ 65Cu M-FeS and Δ 57Fe M-FeS is therefore a product of the superimposed effects of kinetic fractionation of Cu and incomplete equilibrium between metal and sulphide for both isotope systems during cooling. The correlations between Δ 65Cu M-FeS and Δ 57Fe M-FeS are defined by both magmatic and non-magmatic irons record fractional crystallisation and cooling of metallic melts on their respective parent bodies as sulphur and chalcophile elements become excluded from crystallised solid iron and concentrated in the residual melt. Fractional crystallisation processes at shallow levels have been implicated in the two main classes of models for the origin of the non-magmatic iron meteorites; at (i) shallow levels in impact melt models and (ii) at much deeper levels

  8. An in situ synchrotron X-ray diffraction investigation of lepidocrocite and ferrihydrite-seeded Al(OH) 3 crystallisation from supersaturated sodium aluminate liquor

    NASA Astrophysics Data System (ADS)

    Webster, Nathan A. S.; Loan, Melissa J.; Madsen, Ian C.; Knott, Robert B.; Brodie, Greta M.; Kimpton, Justin A.

    2012-02-01

    Lepidocrocite and ferrihydrite-seeded Al(OH) 3 crystallisation from supersaturated sodium aluminate liquor at 70 °C was investigated using in situ synchrotron X-ray diffraction. The presence of iron oxides and oxyhydroxides in the Bayer process has implications for the nucleation and growth of scale on process equipment, and a greater understanding of the effect they have on Al(OH) 3 crystallisation may allow for development of methods for Al(OH) 3 scale prevention. The early stages of both crystallisation reactions were characterised by nucleation of gibbsite on the seed material. This was followed by a rapid increase in gibbsite concentration, which coincided with the appearance of the bayerite and nordstrandite polymorphs of Al(OH) 3. The lepidocrocite-seeded reaction then proceeded via a mechanism similar to that which has been observed previously for goethite, hematite and magnetite-seeded Al(OH) 3 crystallisation. Different behaviour was observed in the ferrihydrite-seeded experiment, with nucleation as well as growth occurring during the period of rapid increase in gibbsite concentration, followed by a period of diffusion controlled growth.

  9. Highlights

    ERIC Educational Resources Information Center

    Mathematical Gazette, 1971

    1971-01-01

    Reprinted are "The Teaching of Euclid" by Bertrand Russell, an article on integrals by G. H. Hardy, "An Address on Relativity" by A. S. Eddington, "The Food of the Gods" by Prof. E. H. Neville, and "Simplicity and Truthfulness in Arithmetic" by W. Hope-Jones. (CT)

  10. Atmospheric Research 2011 Technical Highlights

    NASA Technical Reports Server (NTRS)

    2012-01-01

    The 2011 Technical Highlights describes the efforts of all members of Atmospheric Research. Their dedication to advancing Earth Science through conducting research, developing and running models, designing instruments, managing projects, running field campaigns, and numerous other activities, is highlighted in this report.

  11. Pre- and syn-eruptive degassing and crystallisation processes of the 2010 and 2006 eruptions of Merapi volcano, Indonesia

    NASA Astrophysics Data System (ADS)

    Preece, Katie; Gertisser, Ralf; Barclay, Jenni; Berlo, Kim; Herd, Richard A.

    2014-10-01

    The 2010 eruption of Merapi (VEI 4) was the volcano's largest since 1872. In contrast to the prolonged and effusive dome-forming eruptions typical of Merapi's recent activity, the 2010 eruption began explosively, before a new dome was rapidly emplaced. This new dome was subsequently destroyed by explosions, generating pyroclastic density currents (PDCs), predominantly consisting of dark coloured, dense blocks of basaltic andesite dome lava. A shift towards open-vent conditions in the later stages of the eruption culminated in multiple explosions and the generation of PDCs with conspicuous grey scoria and white pumice clasts resulting from sub-plinian convective column collapse. This paper presents geochemical data for melt inclusions and their clinopyroxene hosts extracted from dense dome lava, grey scoria and white pumice generated during the peak of the 2010 eruption. These are compared with clinopyroxene-hosted melt inclusions from scoriaceous dome fragments from the prolonged dome-forming 2006 eruption, to elucidate any relationship between pre-eruptive degassing and crystallisation processes and eruptive style. Secondary ion mass spectrometry analysis of volatiles (H2O, CO2) and light lithophile elements (Li, B, Be) is augmented by electron microprobe analysis of major elements and volatiles (Cl, S, F) in melt inclusions and groundmass glass. Geobarometric analysis shows that the clinopyroxene phenocrysts crystallised at depths of up to 20 km, with the greatest calculated depths associated with phenocrysts from the white pumice. Based on their volatile contents, melt inclusions have re-equilibrated during shallower storage and/or ascent, at depths of ~0.6-9.7 km, where the Merapi magma system is interpreted to be highly interconnected and not formed of discrete magma reservoirs. Melt inclusions enriched in Li show uniform "buffered" Cl concentrations, indicating the presence of an exsolved brine phase. Boron-enriched inclusions also support the presence of a

  12. Johnson Space Center 2012 Highlights

    NASA Video Gallery

    The year has seen many highlights at NASA’s Johnson Space Center, Houston in the realm of human spaceflight exploration, international and commercial partnerships, and research and technology dev...

  13. LAMA Preconference and Program Highlights.

    ERIC Educational Resources Information Center

    Library Administration & Management, 1988

    1988-01-01

    Highlights events of the Library Administration and Management Association 1988 conference, including presentation of awards and programs on: (1) transfer of training; (2) hiring; (3) mentoring; (4) acquisitions automation; (5) library building consultation; and (6) managing shared systems. (MES)

  14. Research and technology highlights, 1993

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This report contains highlights of the major accomplishments and applications that have been made by Langley researchers and by our university and industry colleagues during the past year. The highlights illustrate both the broad range of the research and technology activities supported by NASA Langley Research Center and the contributions of this work toward maintaining United States leadership in aeronautics and space research. This report also describes some of the Center's most important research and testing facilities.

  15. Ba4Ru3O10.2(OH)1.8: a new member of the layered hexagonal perovskite family crystallised from water.

    PubMed

    Hiley, Craig I; Lees, Martin R; Hammond, David L; Kashtiban, Reza J; Sloan, Jeremy; Smith, Ronald I; Walton, Richard I

    2016-05-11

    A new barium ruthenium oxyhydroxide Ba4Ru3O10.2(OH)1.8 crystallises under hydrothermal conditions at 200 °C: powder neutron diffraction data show it adopts an 8H hexagonal perovskite structure with a new stacking sequence, while high resolution electron microscopy reveals regions of ordered layers of vacant Ru sites, and magnetometry shows antiferromagnetism with TN = 200(5) K. PMID:27074292

  16. Nature of mantle source contributions and the role of contamination and in situ crystallisation in the petrogenesis of Proterozoic mafic dykes and flood basalts Labrador

    NASA Astrophysics Data System (ADS)

    Cadman, A. C.; Tarney, J.; Baragar, W. R. A.

    1995-12-01

    Proterozoic tholeiitic dyke swarms share many compositional features with, and pose similar petrogenetic problems to, Phanerozoic continental flood basalts, but there are few extrusive equivalents of such swarms. The Mesoproterozoic (1.27 Ga) Harp dyke swarm in Labrador is one where possible extrusive equivalents exist in the Seal Lake group, but are slightly displaced in space and time, and can probably be related by models of progressive crustal extension. Here we try to evaluate the roles of crystal differentiation, in situ crystallisation, crustal assimilation and the relative contributions of asthenosphere- and lithosphere-derived melts in the petrogenesis of the mafic magmas. Modelling of the major and trace element variations both within individual dykes and between dykes, and within the lava sequence, does not suggest an important role for continental crust involvement. While in situ crystallisation processes could account for some of the compositional variations, the most successful models invoke mixing or contamination of asthenospheric magmas with/by veined material in the lower lithosphere / upper asthenosphere which carries the ‘continental’ characteristics. The results imply an important role for hydrous phases such as phlogopite and hornblende in the sub-lithosphere mantle. Much of the low-MgO character of mafic dykes may result from significant removal of mafic phases during in situ crystallisation within the lithosphere.

  17. Influence of ZnO/MgO substitution on sintering, crystallisation, and bio-activity of alkali-free glass-ceramics.

    PubMed

    Kapoor, Saurabh; Goel, Ashutosh; Correia, Ana Filipa; Pascual, Maria J; Lee, Hye-Young; Kim, Hae-Won; Ferreira, José M F

    2015-08-01

    The present study reports on the influence of partial replacement of MgO by ZnO on the structure, crystallisation behaviour and bioactivity of alkali-free bioactive glass-ceramics (GCs). A series of glass compositions (mol%): 36.07 CaO-(19.24-x) MgO-x ZnO-5.61 P2O5-38.49 SiO2-0.59 CaF2 (x=2-10) have been synthesised by melt-quench technique. The structural changes were investigated by solid-state magic angle spinning nuclear magnetic resonance (MAS-NMR), X-ray diffraction and differential thermal analysis. The sintering and crystallisation behaviours of glass powders were studied by hot-stage microscopy and differential thermal analysis, respectively. All the glass compositions exhibited good densification ability resulting in well sintered and mechanically strong GCs. The crystallisation and mechanical behaviour were studied under non-isothermal heating conditions at 850 °C for 1h. Diopside was the primary crystalline phase in all the GCs followed by fluorapatite and rankinite as secondary phases. Another phase named petedunnite was identified in GCs with ZnO content >4 mol. The proliferation of mesenchymal stem cells (MSCs) and their alkaline phosphatase activity (ALP) on GCs was revealed to be Zn-dose dependent with the highest performance being observed for 4 mol% ZnO. PMID:26042713

  18. Methyl tetra-O-acetyl-α-D-glucopyranuronate: crystal structure and influence on the crystallisation of the β anomer.

    PubMed

    Hayes, John A; Eccles, Kevin S; Lawrence, Simon E; Moynihan, Humphrey A

    2016-04-29

    Methyl tetra-O-acetyl-β-D-glucopyranuronate (1) and methyl tetra-O-acetyl-α-D-glucopyranuronate (3) were isolated as crystalline solids and their crystal structures were obtained. That of the β anomer (1) was the same as that reported by Root et al., while anomer (3) was found to crystallise in the orthorhombic space group P212121 with two independent molecules in the asymmetric unit. No other crystal forms were found for either compound upon recrystallisation from a range of solvents. The α anomer (3) was found to be an impurity in initially precipitated batches of β-anomer (1) in quantities <3%; however, it was possible to remove the α impurity either by recrystallisation or by efficient washing, i.e. the α anomer is not incorporated inside the β anomer crystals. The β anomer (1) was found to grow as prisms or needles elongated in the a crystallographic direction in the absence of the α impurity, while the presence of the α anomer (3) enhanced this elongation. PMID:27031190

  19. Tail proteins of phage T5: investigation of the effect of the His6-tag position, from expression to crystallisation.

    PubMed

    Noirclerc-Savoye, Marjolaine; Flayhan, Ali; Pereira, Cindy; Gallet, Benoit; Gans, Pierre; Ebel, Christine; Breyton, Cécile

    2015-05-01

    Upon binding to its bacterial host receptor, the tail tip of phage T5 perforates, by an unknown mechanism, the heavily armoured cell wall of the host. This allows the injection of phage DNA into the cytoplasm to hijack the cell machinery and enable the production of new virions. In the perspective of a structural study of the phage tail, we have systematically overproduced eight of the eleven T5 tail proteins, with or without a N- or a C-terminal His6-tag. The widely used Hi6-tag is very convenient to purify recombinant proteins using immobilised-metal affinity chromatography. The presence of a tag however is not always innocuous. We combined automated gene cloning and expression tests to rapidly identify the most promising constructs for proteins of phage T5 tail, and performed biochemical and biophysical characterisation and crystallisation screening on available proteins. Automated small-scale purification was adapted for two highly expressed proteins. We obtained structural information for three of the proteins. We showed that the presence of a His6-tag can have drastic effect on protein expression, solubility, oligomerisation propensity and crystal quality. PMID:25676818

  20. ASTD's 1974 Conference--Highlights

    ERIC Educational Resources Information Center

    Training and Development Journal, 1974

    1974-01-01

    Highlights of speeches presented at the 30th ASTD National Conference in San Francisco are given: S.I. Hayakawa outlined developments in higher education during the 1970's; Joe Batten called for life enrichment, not just job enrichment; and Dorothy Jongeward discussed transactional analysis as a tool for more effective interpersonal relationships.…

  1. CEAS-ASC highlights 2006

    NASA Astrophysics Data System (ADS)

    Caro, Stéphane

    2007-07-01

    The Council of European Aerospace Societies (CEAS) Aeroacoustics Specialists Committee (ASC) supports and promotes the interests of the scientific and industrial aeroacoustics community on a European scale and European aeronautics activities internationally. In this context, "aeroacoustics" encompasses all aerospace acoustics and related areas. Each year the committee highlights some of the research and development projects in Europe. This paper is a report on some highlights of aeroacoustics research in Europe in 2006, compiled from information provided to the ASC of the CEAS. During 2006, numerous research programmes were funded by the European Union. Some of the contributions submitted to the editor summarize selected findings from these programmes, while other articles cover issues supported by national associations. Furthermore, a concise summary of the workshop on "Aeroacoustics of Jet Noise" held in Dublin in September is included in this report. Enquiries concerning all contributions should be addressed to the authors who are given at the end of each subsection.

  2. Research and technology highlights, 1992

    NASA Technical Reports Server (NTRS)

    1993-01-01

    The mission of the NASA Langley Research Center is to increase the knowledge and capability of the United States in a full range of aeronautics disciplines and in selected space disciplines. This mission will be accomplished by performing innovative research relevant to national needs and Agency goals, transferring technology to users in a timely manner, and providing development support to other United States Government agencies, industry, and other NASA centers. Highlights of the major accomplishments and applications that have been made by Langley researchers and by our university and industry colleagues during the past year are presented. The highlights illustrate both the broad range of research and technology (R&T) activities supported by NASA Langley Research Center and the contributions of this work toward maintaining United States leadership in aeronautics and space research. Some of the Center's most important research and testing facilities are also described.

  3. Langley aerospace test highlights, 1990

    NASA Technical Reports Server (NTRS)

    1991-01-01

    The role of NASA-Langley is to perform basic and applied research necessary for the advancement of aeronautics and spaceflight, to generate new and advanced concepts for the accomplishment of related national goals, and to provide research advice, technological support, and assistance to other NASA installations, other government agencies, and industry. Some of the significant tests are highlighted which were performed during 1990 in the NASA-Langley test facilities, a number of which are unique in the world. Both the broad range of the research and technology activities at NASA-Langley and the contributions of this work toward maintaining U.S. leadership in aeronautics and space research are illustrated. Other highlights of Langley research and technology for 1990 are described in Research and Technology 1990 Langley Research Center.

  4. Langley aerospace test highlights, 1985

    NASA Technical Reports Server (NTRS)

    1986-01-01

    The role of the Langley Research Center is to perform basic and applied research necessary for the advancement of aeronautics and space flight, to generate new and advanced concepts for the accomplishment of related national goals, and to provide research advice, technological support, and assistance to other NASA installations, other government agencies, and industry. Significant tests which were performed during calendar year 1985 in Langley test facilities, are highlighted. Both the broad range of the research and technology activities at the Langley Research Center and the contributions of this work toward maintaining United States leadership in aeronautics and space research, are illustrated. Other highlights of Langley research and technology for 1985 are described in Research and Technology-1985 Annual Report of the Langley Research Center.

  5. Langley aerospace test highlights, 1989

    NASA Technical Reports Server (NTRS)

    1990-01-01

    The role of the NASA Langley Research Center is to perform basic and applied research necessary for the advancement of aeronautics and spaceflight, to generate new and advanced concepts for the accomplishment of related national goals, and to provide research advice, technological support, and assistance to other NASA installations, other government agencies, and industry. Some of the significant tests that were performed during calendar year 1989 in the NASA Langley Research Center test facilities are highlighted. Both the broad range of the research and technology activities at the NASA Langley Research Center are illustrated along with the contributions of this work toward maintaining United States leadership in aeronautics and space research. Other highlights of Langley research and technology for 1989 are described in Research and Technology 1989 - Langley Research Center.

  6. Tourette syndrome research highlights 2015

    PubMed Central

    Richards, Cheryl A.; Black, Kevin J.

    2016-01-01

    We present selected highlights from research that appeared during 2015 on Tourette syndrome and other tic disorders. Topics include phenomenology, comorbidities, developmental course, genetics, animal models, neuroimaging, electrophysiology, pharmacology, and treatment. We briefly summarize articles whose results we believe may lead to new treatments, additional research or modifications in current models of TS. PMID:27429744

  7. Highlights of Spanish Astrophysics VII

    NASA Astrophysics Data System (ADS)

    Guirado, J. C.; Lara, L. M.; Quilis, V.; Gorgas, J.

    2013-05-01

    "Highlights of Astronomy and Astrophysics VII" contains the Proceedings of the biannual meeting of the Spanish Astronomical Society held in Valencia from July 9 to 13, 2012. Over 300 astronomer, both national and international researchers, attended to the conference covering a wide variety of astrophysical topics: Galaxies and Cosmology, The Milky Way and Its Components, Planetary Sciences, Solar Physics, Instrumentation and Computation, and Teaching and Outreach of Astronomy.

  8. Research and Technology Highlights 1995

    NASA Technical Reports Server (NTRS)

    1996-01-01

    The mission of the NASA Langley Research Center is to increase the knowledge and capability of the United States in a full range of aeronautics disciplines and in selected space disciplines. This mission is accomplished by performing innovative research relevant to national needs and Agency goals, transferring technology to users in a timely manner, and providing development support to other United States Government agencies, industry, other NASA Centers, the educational community, and the local community. This report contains highlights of the major accomplishments and applications that have been made by Langley researchers and by our university and industry colleagues during the past year. The highlights illustrate both the broad range of research and technology (R&T) activities carried out by NASA Langley Research Center and the contributions of this work toward maintaining United States leadership in aeronautics and space research. An electronic version of the report is available at URL http://techreports.larc.nasa.gov/RandT95. This color version allows viewing, retrieving, and printing of the highlights, searching and browsing through the sections, and access to an on-line directory of Langley researchers.

  9. ESO PR Highlights in 2003

    NASA Astrophysics Data System (ADS)

    2004-01-01

    Among the many astronomical highlights of 2003, the Transit of Mercury certainly attracted great attention as shown by the record number of hits the ESO web page received on that day. But this was a mere rehearsal of an even bigger event we will enjoy in 2004: the Venus Transit. ESO, in partnership with several institutions, is organising a major educational event in connection with it. During 2003, the ESO Educational Office was also involved in various other programmes. They included the web-based "Catch a Star!" and the "Physics and Life" projects, organised with EC sponsorship in connection with the 2003 European Science and Technology Week. The ALMA project, an European-North American collaboration to build an array of 64 12-m submillimetre antennas, moved forward with the signature of the agreement between ESO and the NSF and with the Ground-breaking at Chajnantor. Conceptual studies of a 100-m optical/infrared telescope (OWL) also proceeded well. Several new instruments were installed at ESO telescopes, e.g. HARPS . And the VLT Interferometer (VLTI) received a powerful Adaptive Optics System and made the first detection through infrared interferometry of an extragalactic object. A rapidly increasing number of new scientific results were obtained on the basis of data from ESO telescopes, some of which were highlighted in ESO Press Releases. A number of beautiful images were published. Many of these developments are described in ESO's Press Releases, most with Press Photos, cf. the 2003 PR Index. Some of last year's ESO PR highlights may be accessed directly via the clickable image above.

  10. Recent Highlights of ATVB Atherosclerosis

    PubMed Central

    Lu, Hong; Daugherty, Alan

    2015-01-01

    Summary Mechanistic studies over the past decades using in vitro systems, animal models, and human tissues have highlighted the complexity of pathophysiological processes of atherosclerosis. Hypercholesterolemia, as one of the major risk factors for the development and progression of atherosclerosis, is still the focus of many mechanistic studies and the major therapeutic target of atherosclerosis. Although there is a dire need to validate many experimental findings in humans, there is a large number of approaches that have been showing promise for contributing to future therapeutic strategies. PMID:25717174

  11. Compare and contrast the effects of surfactants (PluronicF-127 and CremophorEL) and sugars (β-cyclodextrin and inulin) on properties of spray dried and crystallised lysozyme.

    PubMed

    Haj-Ahmad, Rita Rochdy; Elkordy, Amal Ali; Chaw, Cheng Shu; Moore, Adrian

    2013-07-16

    The stabilisation of proteins using different excipients in dried forms for possible therapeutic use is extensively studied. However, the effects of excipients on proteins in crystallised forms are sparsely documented. Therefore, the influences of PluronicF-127 and CremophorEL (as surfactants) and β-cyclodextrin and inulin (as sugars) on stability and biological activity of lysozyme, a model protein, in spray dried and crystallised forms were investigated. Spray dried and crystallised lysozyme were prepared in absence and presence of the mentioned excipients in a concentration of 0.05% w/v. The protein formulations were characterised in both solution state (using biological assay, particle size analysis and protein concentration determination) and solid state (employing yield determination, scanning electron microscopic (SEM) examination, Fourier transform infrared (FT-IR) spectroscopy for secondary structure analysis and Differential Scanning Calorimetry (DSC) for thermal study). Also, protein samples were assayed for their biological activities after exposing to storage stability study for 20 weeks in solid states at 24 °C/76% relative humidity (RH) and in aqueous states at 24 °C. The results showed that lysozyme crystals with CremophorEL, PluronicF-127, β-cyclodextrin and inulin maintained protein thermal stability (as indicated by DSC) to greater extent compared with spray dried protein formulations. Also, PluronicF-127 was competent to recover 100% lysozyme from crystallisation protein solutions (as confirmed by yield determination); this surfactant was able to prevent aggregate formation within spray dried lysozyme (as demonstrated by particle size analysis). The presence of PluronicF-127, β-cyclodextrin and inulin preserved the protein biological activity in freshly prepared spray dried and crystallised samples. PluronicF-127 was competent to protect lysozyme in both spray dried and crystallised forms after storage. PluronicF-127 has proved to be a

  12. Cluster highlights in magnetospheric physics

    NASA Astrophysics Data System (ADS)

    Escoubet, C. Philippe; Laakso, Harri; Taylor, Matthew; Goldstein, Mevlyn; Hapgood, Mike; Masson, Arnaud; Volpp, Juergen; Sieg, Detlef

    The Cluster mission has been operated successfully for 14 years. As the first science mission comprising four identical spacecraft, Cluster has faced many challenges during its lifetime: its long selection process together with SOHO, the failure of the first Ariane V launch, its fast rebuilt, and the launch on two Soyuz rockets in 2000. The separation of the Cluster spacecraft was changed more than 25 times from a few kilometers up to 36000 km to address the various scientific objectives; the smallest distance achieved between two Cluster spacecraft was 4 km, about 50 times smaller than planned at the beginning of the mission. The main goal of the Cluster mission is to study in three dimensions small-scale plasma structures in key plasma regions of Earth’s geospace environment: solar wind and bow shock, magnetopause, polar cusps, magnetotail, plasmasphere and auroral zone. We will present science highlights obtained such as ripples on the bow shock, 3D current measurements and Kelvin-Helmholtz waves at the magnetopause, bifurcated current sheet in the magnetotail, and first measurement of the electron pressure tensor near a site of magnetic reconnection. In addition, we highlight Cluster results on understanding the impact of Coronal Mass Ejections (CME) on the Earth's environment. We will also present the distribution of data through the Cluster Science Data System (CSDS), and the Cluster Archive. Those systems were implemented to provide, for the first time for a plasma physics mission, a permanent and public archive of all the high resolution data from all instruments.

  13. A Dual-Porosity, In Situ Crystallisation Model For Fast-Spreading Mid-Ocean Ridge Magma Chambers Based Upon Direct Observation From Hess Deep

    NASA Astrophysics Data System (ADS)

    MacLeod, C. J.; Lissenberg, C. J.

    2014-12-01

    We propose a revised magma chamber model for fast-spreading mid-ocean ridges based upon a synthesis of new data from a complete section of lower crust from the East Pacific Rise, reconstructed from samples collected from the Hess Deep rift valley during cruise JC21. Our investigation includes detailed sampling across critical transitions in the upper part of the plutonic section, including the inferred axial melt lens (AML) within the dyke-gabbro transition. We find that an overall petrological progression, from troctolite and primitive gabbro at the base up into evolved (oxide) gabbro and gabbronorite at the top of the lower crustal section, is mirrored by a progressive upward chemical fractionation as recorded in bulk rock and mineral compositions. Crystallographic preferred orientations measured using EBSD show that the downward increase in deformation of mush required in crystal subsidence models is not observed. Together these observations are consistent only with a model in which crystallisation of upward migrating evolving melts occurs in situ in the lower crust. Over-enrichment in incompatible trace element concentrations and ratios above that possible by fractional crystallisation is ubiquitous. This implies redistribution of incompatible trace elements in the lower crust by low porosity, near-pervasive reactive porous flow of interstitial melt moving continuously upward through the mush pile. Mass balance calculations reveal a significant proportion of this trace element enriched melt is trapped at mid-crustal levels. Mineral compositions in the upper third to half of the plutonic section are too evolved to represent the crystal residues of MORB. Erupted MORB therefore must be fed from melts sourced in the deeper part of the crystal mush pile, and which must ascend rapidly without significant modification in the upper plutonics or AML. From physical models of mush processes we posit that primitive melts are transported through transient, high porosity

  14. Laboratory studies on recovery of N and P from human urine through struvite crystallisation and zeolite adsorption.

    PubMed

    Bán, Zs; Dave, G

    2004-01-01

    Struvite [Mg (K, NH4)(PO4) x 6H2O] crystallisation and adsorption to zeolite have been proposed as a method for nutrient recovery from human urine collected with urine separating toilets. The aim of the present study was to optimise the use of MgO (to precipitate struvite) and zeolite (to adsorb ammonia) in this process. The experiments were performed with fresh urine, to which various amounts of MgO and zeolite were added. After repeated stirring and settling for 3 days the supernatant was analysed for pH, total-N, total-P and acute toxicity for Daphnia magna (24- and 48-h EC50). The results show that addition of MgO reduced P and addition of zeolite reduced N in the supernatant, as expected. The required concentration of MgO added was less than expected from the stoichiometric Mg-P-ratio for struvite. In combination with zeolite the requirement for MgO was reduced even further. Zeolite was effective in reducing total-N, but because of its interaction with MgO the effect of zeolite on N as well as P reduction was rather complicated. The optimal combination of MgO and zeolite for combined N and P recovery was found to be around 0.5 MgO per litre urine and 15 g zeolite per litre urine. These additions reduced supernatant P from about 1300 mg l(-1) to 10 mg l(-1) and N from 8000 mg l(-1) to 1000 mg l(-1). The 24-h EC50 for D. magna was not significantly affected by these additions. The expected recovery potentials for P and N by addition of MgO and zeolite are, thus, about 99% for P and 90% for N. However, these figures need to be verified, and pilot plant experiments at a science centre with urine separation wastewater treatment (www.universeum.se) are in progress. PMID:15027655

  15. Highlights in pathogenesis of vitiligo

    PubMed Central

    Mohammed, Ghada F; Gomaa, Amal HA; Al-Dhubaibi, Mohammed Saleh

    2015-01-01

    Vitiligo is a common pigmentary disorder. Many studies across decades and all over the world have attempted to illustrate the pathogenesis behind it; however, the pathogenesis of vitiligo remains elusive. This review article, we present the findings behind the most and updated theories behind this psychologically debilitating and disfiguring disease. The discussion begun with the role of genetic predisposition followed by neural theory first proposed in the 1950s. We highlight the autoimmune hypothesis, followed by the reactive oxygen species model, zinc-α2-glycoprotein deficiency hypothesis, viral theory, intrinsic theory and biochemical, molecular and cellular alterations accounting for loss of functioning melanocytes in vitiligo. Many theories were elaborated to clarify vitiligo pathogenesis. It is a multifactorial disease involving the interplay of several factors. Future research is needed to clarify the interaction of these factors for better understanding of vitiligo pathogenesis and subsequent successful treatment. PMID:25789295

  16. Langley aerospace test highlights, 1988

    NASA Technical Reports Server (NTRS)

    1989-01-01

    The role of the Langley Research Center is to perform basic and applied research necessary for the advancement of aeronautics and space flight, to generate new and advanced concepts for the accomplishment of related national goals, and to provide research advice, technological support, and assistance to other NASA installations, other government agencies, and industry. Some of the significant tests which were performed during calendar year 1988 in Langley test facilities, a number of which are unique in the world are highlighted. Both the broad range of the research and technology activities at the Langley Research Center and the contributions of this work toward maintaining United States leadership in aeronautics and space research are illustrated.

  17. CP VIOLATION HIGHLIGHTS: CIRCA 2005

    SciTech Connect

    SONI A.

    2005-02-27

    Recent highlights in CP violation phenomena, are reviewed. B-factory results imply that, CP-violation phase in the CKM matrix is the dominant contributor to the observed CP violation in K and B-physics. Deviations from the predictions of the CKM-paradigm due to beyond the Standard Model CP-odd phase are likely to be a small perturbation. Therefore, large data sample of clean B's will be needed. Precise determination of the unitarity triangle, along with time dependent CP in penguin dominated hadronic and radiative modes are discussed. Null tests in B, K and top-physics and separate determination of the K-unitarity triangle are also emphasized.

  18. Highlights in pathogenesis of vitiligo.

    PubMed

    Mohammed, Ghada F; Gomaa, Amal Ha; Al-Dhubaibi, Mohammed Saleh

    2015-03-16

    Vitiligo is a common pigmentary disorder. Many studies across decades and all over the world have attempted to illustrate the pathogenesis behind it; however, the pathogenesis of vitiligo remains elusive. This review article, we present the findings behind the most and updated theories behind this psychologically debilitating and disfiguring disease. The discussion begun with the role of genetic predisposition followed by neural theory first proposed in the 1950s. We highlight the autoimmune hypothesis, followed by the reactive oxygen species model, zinc-α2-glycoprotein deficiency hypothesis, viral theory, intrinsic theory and biochemical, molecular and cellular alterations accounting for loss of functioning melanocytes in vitiligo. Many theories were elaborated to clarify vitiligo pathogenesis. It is a multifactorial disease involving the interplay of several factors. Future research is needed to clarify the interaction of these factors for better understanding of vitiligo pathogenesis and subsequent successful treatment. PMID:25789295

  19. Atmospheric Research 2012 Technical Highlights

    NASA Technical Reports Server (NTRS)

    Lau, William K -M.

    2013-01-01

    This annual report, as before, is intended for a broad audience. Our readers include colleagues within NASA, scientists outside the Agency, science graduate students, and members of the general public. Inside are descriptions of atmospheric research science highlights and summaries of our education and outreach accomplishments for calendar year 2012.The report covers research activities from the Mesoscale Atmospheric Processes Laboratory, the Climate and Radiation Laboratory, the Atmospheric Chemistry and Dynamics Laboratory, and the Wallops Field Support Office under the Office of Deputy Director for Atmospheres, Earth Sciences Division in the Sciences and Exploration Directorate of NASAs Goddard Space Flight Center. The overall mission of the office is advancing knowledge and understanding of the Earths atmosphere. Satellite missions, field campaigns, peer-reviewed publications, and successful proposals are essential to our continuing research.

  20. Highlighting inconsistencies regarding metal biosorption.

    PubMed

    Robalds, Artis; Naja, Ghinwa Melodie; Klavins, Maris

    2016-03-01

    Thousands of articles have been devoted to examine different types of biosorbents and their use in cleaning polluted waters. An important objective of some studies has been the identification of the biosorption mechanisms. This type of investigation is not always performed, as it can only be done if scientists are aware of all mechanisms that, at least theoretically, control the removal of the target substances. Mistakes are often made, even in highly cited review articles, where biosorption mechanisms are named and/or grouped. The aim of this article is to highlight errors and inaccuracies as well as to discuss different classification systems of the biosorption mechanisms. This article serves as a guide, as well as a platform for discussion among researchers involved in the investigation of biosorbents, in an effort to avoid reproducing errors in subsequent articles. PMID:26607871

  1. Langley aerospace test highlights - 1986

    NASA Technical Reports Server (NTRS)

    1987-01-01

    The role of the Langley Research Center is to perform basic and applied research necessary for the advancement of aeronautics and space flight, to generate new and advanced concepts for the accomplishment of related national goals, and to provide research advice, technological support, and assistance to other NASA installations, other government agencies, and industry. This report highlights some of the significant tests which were performed during calendar year 1986 in Langley test facilities, a number of which are unique in the world. The report illustrates both the broad range of the research and technology activities at the Langley Research Center and the contributions of this work toward maintaining United States leadership in aeronautics and space research.

  2. Highlights of Coastal Waves 1996.

    NASA Astrophysics Data System (ADS)

    Rogers, David P.; Dorman, Clive E.; Edwards, Kathleen A.; Brooks, Ian M.; Melville, W. Kendall; Burk, Stephen D.; Thompson, William T.; Holt, Teddy; Ström, Linda M.; Tjernström, Michael; Grisogono, Branko; Bane, John M.; Nuss, Wendell A.; Morley, Bruce M.; Schanot, Allen J.

    1998-07-01

    Some of the highlights of an experiment designed to study coastal atmospheric phenomena along the California coast (Coastal Waves 1996 experiment) are described. This study was designed to address several problems, including the cross-shore variability and turbulent structure of the marine boundary layer, the influence of the coast on the development of the marine layer and clouds, the ageostrophy of the flow, the dynamics of trapped events, the parameterization of surface fluxes, and the supercriticality of the marine layer.Based in Monterey, California, the National Center for Atmospheric Research (NCAR) C-130 Hercules and the University of North Carolina Piper Seneca obtained a comprehensive set of measurements on the structure of the marine layer. The study focused on the effects of prominent topographic features on the wind. Downstream of capes and points, narrow bands of high winds are frequently encountered. The NCAR-designed Scanning Aerosol Backscatter Lidar (SABL) provided a unique opportunity to connect changes in the depth of the boundary layer with specific features in the dynamics of the flow field.An integral part of the experiment was the use of numerical models as forecast and diagnostic tools. The Naval Research Laboratory's Coupled Ocean Atmosphere Model System (COAMPS) provided high-resolution forecasts of the wind field in the vicinity of capes and points, which aided the deployment of the aircraft. Subsequently, this model and the MIUU (University of Uppsala) numerical model were used to support the analysis of the field data.These are some of the most comprehensive measurements of the topographically forced marine layer that have been collected. SABL proved to be an exceptionally useful tool to resolve the small-scale structure of the boundary layer and, combined with in situ turbulence measurements, provides new insight into the structure of the marine atmosphere. Measurements were made sufficiently far offshore to distinguish between the

  3. ESO PR Highlights in 2000

    NASA Astrophysics Data System (ADS)

    2001-01-01

    At the beginning of the new millennium, ESO and its staff are facing the future with confidence. The four 8.2-m Unit Telescopes of the Very Large Telescope (VLT) are in great shape and the VLT Interferometer (VLTI) will soon have "first fringes". The intercontinental ALMA project is progressing well and concepts for extremely large optical/infrared telescopes are being studied. They can also look back at a fruitful and rewarding past year. Perhaps the most important, single development has been the rapid transition of the Very Large Telescope (VLT). From being a "high-tech project under construction" it has now become a highly proficient, world-class astronomical observatory. This trend is clearly reflected in ESO's Press Releases , as more and more front-line scientific results emerge from rich data obtained at this very efficient facility. There were also exciting news from several of the instruments at La Silla. At the same time, the ESO community may soon grow, as steps towards membership are being taken by various European countries. Throughout 2000, a total of 54 PR communications were made, with a large number of Press Photos and Video Clips, cf. the 2000 PR Index. Some of the ESO PR highlights may be accessed directly via the clickable image on the present page. ESO PR Photo 01/01 is also available in a larger (non-clickable) version [ JPEG: 566 x 566 pix - 112k]. It may be reproduced, if credit is given to the European Southern Observatory.

  4. ESO PR Highlights in 2004

    NASA Astrophysics Data System (ADS)

    2005-01-01

    new interesting scientific results on the basis of data from ESO telescopes, including several results from the unmatched interferometer mode of the VLT, the VLTI, some of which were highlighted in ESO Press Releases. Certainly worth noting is the possible first ever bona-fide image of an exoplanet and the discovery of the lightest known exoplanet . At the beginning of the year, Paranal welcomed the first Auxiliary Telescope, while on the instrument side as well, 2004 was a good year: we saw the arrival of SINFONI on the VLT, of AMBER on the VLTI, and the installation at the NACO Adaptive Optics instrument of the " Simultaneous Differential Imager (SDI)" to detect exoplanets. And the first prototype of the Astrophysical Virtual Observatory was able to provide unprecedented results on the existence of Type-2 quasars by discovering an entire population of obscured, powerful supermassive black holes. Many of these developments are described in ESO's Press Releases, most with Press Photos, cf. the 2004 PR Index. Some of last year's ESO PR highlights may be accessed directly via the clickable image above.

  5. Highlighting Your Science to NASA

    NASA Astrophysics Data System (ADS)

    Sharkey, C.

    2003-12-01

    An effort is underway to provide greater visibility within NASA headquarters, and to those who provide funding to NASA, of the outstanding work that is being performed by scientists involved in the Solar System Exploration Research and Analysis Programs, most of whom are DPS members. In support of this effort, a new feature has been developed for the NASA Headquarters Solar System Exploration Division web site whereby researchers can provide a synopsis of their current research results. The site (http://solarsystem.nasa.gov/spotlight/ - Username: your email address Password: sse) is an online submission area where NASA-funded scientists can upload the results of their research. There they provide their contact information, briefly describe their research, and upload any associated images or graphics. The information is available to a limited number of reviewers and writers at JPL. Each month, one researcher's work will be chosen as a science spotlight. After a writer interviews the scientist, a brief Power Point presentation that encapsulates their work will be given to Dr. Colleen Hartman at NASA headquarters. She will then present the exciting findings to Associate Administrator for Space Science, Dr. Ed Weiler. The information from some of these highlights can serve as a basis to bring Principal Investigators to NASA Headquarters for exposure to media through Space Science Updates on NASA television. In addition, the science results may also be incorporated into briefing material for the Office of Management and Budget and congressional staffers. Some spotlights will also be converted into feature stories for the Solar System Exploration website so the public, too, can learn about exciting new research. The site, http://solarsystem.nasa.gov/, is one of NASA's most visited. Over the past decade, there has been a trend of flat budgets for Research and Analysis activities. By giving more visibility to results of Solar System research, our goal is to encourage

  6. ESO PR Highlights in 2005

    NASA Astrophysics Data System (ADS)

    2006-01-01

    2005 was the year of Physics. It was thus also in part the year of astronomy and this is clearly illustrated by the numerous breakthroughs that were achieved, in particular using ESO's telescopes. One of the highlights was without any doubt the confirmation of the first image of an exoplanet , around the star 2M1207 (see ESO PR 12/05). ESO's telescopes also found a Neptune-mass exoplanet around a small star ( PR 30/05) - a discovery that proves crucial in the census of other planetary systems, and imaged a tiny companion in the close vicinity of the star GQ Lupi, a very young object still surrounded by a disc, with an age between 100,000 and 2 million years ( PR 09/05). Moreover, using a new high-contrast adaptive optics camera on the VLT, the NACO Simultaneous Differential Imager, or NACO SDI, astronomers were able for the first time to image a companion 120 times fainter than its star , very near the star AB Doradus A. This companion appears to be almost twice as heavy as theory predicts it to be ( PR 02/05). ESO's telescopes proved very useful in helping to solve a 30-year old puzzle . Astronomers have for the first time observed the visible light from a short gamma-ray burst (GRB). Using the 1.5m Danish telescope at La Silla (Chile), they showed that these short, intense bursts of gamma-ray emission most likely originate from the violent collision of two merging neutron stars ( PR 26/05). Additional evidence came from witnessing another event with the VLT ( PR 32/05). Also in this field, astronomers found the farthest known gamma-ray burst with ESO's VLT, observing an object with a redshift 6.3, i.e. that is seen when the Universe was less than 900 million years old ( PR 22/05). On July 4, NASA's Deep Impact spacecraft plunged onto Comet 9P/Tempel 1 with the aim to create a crater and expose pristine material from beneath the surface. For two days before and six days after, all major ESO telescopes have been observing the comet, in a coordinated fashion and in

  7. ESO PR Highlights in 2001

    NASA Astrophysics Data System (ADS)

    2002-01-01

    great research possibilities at these sites. And this year will also see further development of Europe's Astrophysical Virtual Observatory, a most powerful research tool of the future. Many of these developments are described in ESO's Press Releases , most with Press Photos and several also with PR Video Clips , cf. the 2001 PR Index. Some of last year's ESO PR highlights may be accessed directly via the clickable image on the present page.

  8. Highlights of Astronomy, Volume 14

    NASA Astrophysics Data System (ADS)

    van der Hucht, Karel

    2007-08-01

    Preface Karel A. van der Hucht; Part I. Invited Discourses: Part II. Joint Discussions: 1. Particle acceleration - from Solar System to AGN Marian Karlicky and John C. Brown; 2. Pulsar emission and related phenomena Werner Becker, Janusz A. Gil and Bronislaw Rudak; 3. Solar activity regions and magnetic structure Debi Prasad Choudhary and Michal Sobotka; 4. The ultraviolet universe: Stars from birth to death Ana I. Gomez de Castro and Martin A. Barstow; 5. Calibrating the top of the stellar M-L relationship Claus Leitherer, Anthony F. J. Moat and Joachim Puls; 6. Neutron stars and black holes in star clusters Frederic A. Rasio; 7. The Universe at z > 6 Daniel Schaerer and Andrea Ferrara; 8. Solar and stellar activity cycles Klaus G. Strassmeier and Alexander Kosovichev; 9. Supernovae: One millennium after SN 1006 P. Frank Winkler, Wolfgang Hillebrandt and Brian P. Schmidt; 10. Progress in planetary exploration missions Guy J. Consolmagno; 11. Pre-solar grains as astrophysical tools Anja C. Andersen and John C. Lattanzio; 12. Long wavelength astrophysics T. Joseph W. Lazio and Namir E. Kassim; 13. Exploiting large surveys for galactic astronomy Christopher J. Corbally, Coryn A. L. Bailer-Jones, Sunetra Giridhar and Thomas H. Lloyd Evans; 14. Modeling dense stellar systems Alison I. Sills, Ladislav Subr and Simon F. Portegies Zwart; 15. New cosmology results from the Spitzer Space Telescope George Helou and David T. Frayer; 16. Nomenclature, precession and new models in fundamental astronomy Nicole Capitaine, Jan Vondrak & James L. Hilton; 17. Highlights of recent progress in seismology of the Sun and Sun-like stars John W. Leibacher and Michael J. Thompson; Part III. Special Sessions: SpS 1. Large astronomical facilities of the next decade Gerard F. Gilmore and Richard T. Schilizzi; SpS 2. Innovation in teaching and learning astronomy methods Rosa M. Ros and Jay M. Pasachoff; SpS 3. The Virtual Observatory in action: New science, new technology and next

  9. Fractional Crystallisation of Archaean Trondhjemite Magma at 12-7 Kbar: Constraints on Rheology of Archaean Continental Crust

    NASA Astrophysics Data System (ADS)

    Sarkar, Saheli; Saha, Lopamudra; Satyanarayan, Manavalan; Pati, Jayanta

    2015-04-01

    Fractional Crystallisation of Archaean Trondhjemite Magma at 12-7 Kbar: Constraints on Rheology of Archaean Continental Crust Sarkar, S.1, Saha, L.1, Satyanarayan, M2. and Pati, J.K.3 1. Department of Earth Sciences, Indian Institute of Technology Roorkee, Roorkee-247667, Haridwar, India, 2. HR-ICPMS Lab, Geochemistry Group, CSIR-National Geophysical Research Institute, Hyderabad-50007, India. 3. Department of Earth and Planetary Sciences, Nehru Science Centre, University of Allahabad, Allahabad-211002, India. Tonalite-Trondhjemite-Granodiorite (TTGs) group of rocks, that mostly constitute the Archaean continental crusts, evolved through a time period of ~3.8 Ga-2.7 Ga with major episodes of juvenile magma generations at ~3.6 Ga and ~2.7 Ga. Geochemical signatures, especially HREE depletions of most TTGs conform to formation of this type of magma by partial melting of amphibolites or eclogites at 15-20 kbar pressure. While TTGs (mostly sodic in compositions) dominates the Eoarchaean (~3.8-3.6 Ga) to Mesoarchaean (~3.2-3.0 Ga) domains, granitic rocks (with significantly high potassium contents) became more dominant in the Neoarchaean period. The most commonly accepted model proposed for the formation of the potassic granite in the Neoarchaean time is by partial melting of TTGs along subduction zones. However Archaean granite intrusive into the gabbro-ultramafic complex from Scourie, NW Scotland has been interpreted to have formed by fractional crystallization of hornblende and plagioclase from co-existing trondhjemitic gneiss. In this study we have studied fractional crystallization paths from a Mesoarchaean trondhjemite from the central Bundelkhand craton, India using MELTS algorithm. Fractional crystallization modeling has been performed at pressure ranges of 20 kbar to 7 kbar. Calculations have shown crystallization of garnet-clinopyroxene bearing assemblages with progressive cooling of the magma at 20 kbar. At pressure ranges 19-16 kbar, solid phases

  10. Atmospheric Research 2014 Technical Highlights

    NASA Technical Reports Server (NTRS)

    Platnick, Steven

    2015-01-01

    Earth Sciences Division in atmospheric science research. Figure 1.1 shows the 20-year record of peer-reviewed publications and proposals among the various Laboratories. This data shows that the scientific work being conducted in the Laboratories is competitive with the work being done elsewhere in universities and other government agencies. The office of Deputy Director for Atmospheric Research will strive to maintain this record by rigorously monitoring and promoting quality while emphasizing coordination and integration among atmospheric disciplines. Also, an appropriate balance will be maintained between the scientists' responsibility for large collaborative projects and missions and their need to carry out active science research as a principal investigator. This balance allows members of the Laboratories to improve their scientific credentials, and develop leadership potentials. Interdisciplinary research is carried out in collaboration with other laboratories and research groups within the Earth Sciences Division, across the Sciences and Exploration Directorate, and with partners in universities and other government agencies. Members of the Laboratories interact with the general public to support a wide range of interests in the atmospheric sciences. Among other activities, the Laboratories raise the public's awareness of atmospheric science by presenting public lectures and demonstrations, by making scientific data available to wide audiences, by teaching, and by mentoring students and teachers. The Atmosphere Laboratories make substantial efforts to attract and recruit new scientists to the various areas of atmospheric research. We strongly encourage the establishment of partnerships with Federal and state agencies that have operational responsibilities to promote the societal application of our science products. This report describes our role in NASA's mission, provides highlights of our research scope and activities, and summarizes our scientists' major

  11. Primary welding and crystallisation textures preserved in the intra-caldera ignimbrites of the Permian Ora Formation, northern Italy: implications for deposit thermal state and cooling history

    NASA Astrophysics Data System (ADS)

    Willcock, M. A. W.; Cas, R. A. F.

    2014-06-01

    Exceptional exposure through a Permian intra-caldera ignimbrite fill within the 42 × 40 km Ora caldera (>1,290 km3 erupted volume) provides an opportunity to study welding textures in a thick intra-caldera ignimbrite succession. The ignimbrite succession records primary dense welding, a simple cooling unit structure, common crystallisation zones, and remarkably preserves fresh to slightly hydrated glass in local vitrophyre zones. Evidence for primary syn- and post-emplacement welding consists of (a) viscously deformed and sintered juvenile glass and relict shard textures; (b) complete deposit welding; (c) subtle internal welding intensity variations; (d) vitrophyre preserved locally at the base of the ignimbrite succession; (e) persistent fiamme juvenile clast shapes throughout the succession at the macroscopic and microscopic scales, defining a moderate to well-developed eutaxitic texture; (f) common undulating juvenile clast (pumice) margins and feathery terminations; (g) a general loss of deposit porosity; and (h) perlitic fracturing. A low collapsing or fountaining explosive eruption column model is proposed to have facilitated the ubiquitous welding of the deposit, which in turn helped preserve original textures. The ignimbrite succession preserves no evidence of a time break through the sequence and columnar joints cross-gradational ignimbrite lithofacies boundaries, so the ignimbrite is interpreted to represent a simple cooling unit. Aspect ratio and anisotropy of magnetic susceptibility (AMS) analyses through stratigraphic sections within the thick intra-caldera succession and at the caldera margin reveal variable welding compaction and strain profiles. Significantly, these data show that welding degree/intensity may vary in an apparently simple cooling unit because of variations in eruption process recorded in differing lithofacies. These data imply complex eruption, emplacement, and cooling processes. Three main crystallisation textural zones are

  12. ESO PR Highlights in 2006

    NASA Astrophysics Data System (ADS)

    2007-01-01

    Last year proved to be another exceptional year for the European organisation for ground-based astronomy. ESO should begin the New Year with two new member states: Spain (PR 05/06) and the Czech Republic (PR 52/06). ESO PR Highlights 2006 2006 was a year of renovation and revolution in the world of planets. A new Earth-like exoplanet has been discovered (PR 03/06) using a network of telescopes from all over the world (including the Danish 1.54-m one at ESO La Silla). It is not the only child of this fruitful year: thanks to the combined use of ESO's Very Large Telescope (VLT) and La Silla instruments, a surprising system of twin giant exoplanets was found (PR 29/06), and a trio of Neptune-like planets hosted by a nearby star were identified (PR 18/06). These results open new perspectives on the search for habitable zones and on the understanding of the mechanism of planet formation. The VISIR instrument on the VLT has been providing unique information to answer this last question, by supplying a high resolution view of a planet-forming disc (PR 36/06). There are not only new members in the planets' register: during the General Assembly of the International Astronomical Union held in Prague (Czech Republic), it was decided that Pluto is not a planet anymore but a 'dwarf planet'. Whatever its status, Pluto still has a satellite, Charon, whose radius and density have been measured more accurately by observing a rare occultation from different sites, including Cerro Paranal (PR 02/06). The scientific community dedicated 2006 to the great physicist James Clerk Maxwell (it was the 175th anniversary of the birth): without his electromagnetic theory of light, none of the astonishing discoveries of modern physics could have been achieved. Nowadays we can look at distant galaxies in great detail: the GIRAFFE spectrograph on the VLT revealed that galaxies 6 billion years ago had the same amount of dark matter relative to stars than nowadays (PR 10/06), while SINFONI gave an

  13. ESO PR Highlights in 2007

    NASA Astrophysics Data System (ADS)

    2008-01-01

    Another great year went by for ESO, the European Organisation for Astronomical Research in the Southern Hemisphere. From 1 January 2007, with the official joining of the Czech Republic, ESO has 13 member states, and since September, ESO has a new Director General, Tim de Zeeuw (ESO 03/07 and 38/07). Many scientific discoveries were made possible with ESO's telescopes. Arguably, the most important is the discovery of the first Earth-like planet in the habitable zone of a low-mass red dwarf (ESO 22/07). If there is water on this planet, then it should be liquid! ESO PR Highlights 2007 This is a clickable map. These are only some of the press releases issued by ESO in 2007. For a full listing, please go to ESO 2007 page. In our own Solar System also, astronomers made stunning breakthroughs with ESO's telescopes, observing the effect of the light from the Sun on an asteroid's rotation (ESO 11/07), describing in unprecedented detail the double asteroid Antiope (ESO 18/07), peering at the rings of Uranus (ESO 37/07), discovering a warm south pole on Neptune (ESO 41/07), showing a widespread and persistent morning drizzle of methane over the western foothills of Titan's major continent (ESO 47/07), and studying in the greatest details the wonderful Comet McNaught (ESO 05/07 and 07/07). In the study of objects slightly more massive than planets, the VLT found that brown dwarfs form in a similar manner to normal stars (ESO 24/07). The VLT made it also possible to measure the age of a fossil star that was clearly born at the dawn of time (ESO 23/07). Other discoveries included reconstructing the site of a flare on a solar-like star (ESO 53/07), catching a star smoking (ESO 34/07), revealing a reservoir of dust around an elderly star (ESO 43/07), uncovering a flat, nearly edge-on disc of silicates in the heart of the magnificent Ant Nebula (ESO 42/07), finding material around a star before it exploded (ESO 31/07), fingerprinting the Milky Way (ESO 15/07), revealing a rich

  14. The pharmacological effects of the thermostabilising (m23) mutations and intra and extracellular (β36) deletions essential for crystallisation of the turkey β-adrenoceptor.

    PubMed

    Baker, Jillian G; Proudman, Richard G W; Tate, Christopher G

    2011-07-01

    The X-ray crystal structure of the turkey β-adrenoceptor has recently been determined. However, mutations were introduced into the native receptor that was essential for structure determination. These may cause alterations to the receptor pharmacology. It is therefore essential to understand the effects of these mutations on the pharmacological characteristics of the receptor. This study examined the pharmacological effects of both the m23 mutations and the β36 deletions, both alone and then in combination in the β36-m23 mutant used in the crystallisation and structure determination of the turkey β-adrenoceptor. Stable CHO-K1 cell lines were made of each of the receptor mutants and the affinity and efficacy of ligands assessed by (3)H-CGP 12177 whole cell ligand binding, (3)H-cAMP accumulation, and CRE-SPAP gene transcription assays. The m23 mutations reduced affinity for agonists, partial agonists and neutral antagonists by about tenfold whilst the β36 deletions alone had no effect on ligand affinity. Both sets of changes appeared to reduce the agonist activation of the receptor. Both the m23 and the β36 receptors retained two active agonist-induced receptor conformations similar to that of the original tβtrunc receptor. The combined β36-m23 receptor bound ligands with similar affinity to the m23 receptor; however, agonist activation was only observed with a few agonists including the catecholamines. Although the combination of mutations severely reduced the activation ability, the final crystallised receptor (β36-m23) was still a fully functional receptor capable of binding agonist and antagonist ligands and activating intracellular agonist responses. PMID:21547538

  15. Crystallisation of magmatic topaz and implications for Nb-Ta-W mineralisation in F-rich silicic melts - The Ary-Bulak ongonite massif

    NASA Astrophysics Data System (ADS)

    Agangi, Andrea; Kamenetsky, Vadim S.; Hofmann, Axel; Przybyłowicz, Wojciech; Vladykin, Nikolay V.

    2014-08-01

    Textural, mineralogical and geochemical data on F-rich rhyolite (ongonite) from the Ary-Bulak massif of eastern Transbaikalia help constrain the formation of magmatic topaz. In these rocks, topaz occurs as phenocrysts, thus providing compelling evidence for crystallisation at the orthomagmatic stage. Cathodoluminescence images of topaz and quartz reveal growth textures with multiple truncation events in single grains, indicative of a dynamic system that shifted from saturated to undersaturated conditions with respect to topaz and quartz. Electron microprobe and Raman analyses of topaz indicate near-pure F composition [Al2SiO4F2], with very limited OH replacement. Laser ablation ICP-MS traverses revealed the presence of a large number of trace elements present at sub-ppm to hundreds of ppm levels. The chemical zoning of topaz records trace element fluctuations in the coexisting melt. Concentrations of some trace elements (Li, Ga, Nb, Ta and W) are correlated with cathodoluminescence intensity, thus suggesting that some of these elements act as CL activators in topaz. The study of melt inclusions indicates that melts with different F contents were trapped at different stages during formation of quartz and topaz phenocrysts, respectively. Electron microprobe analyses of glass in subhedral quartz-hosted melt inclusions indicate F ≤ 1.2 wt.%, whereas irregular-shaped melt inclusions hosted in both topaz and quartz have F ≤ 9 wt.%. Cryolithionite [Na3Li3Al2F12] coexists with glass in irregular inclusions, implying high Li contents in the melt. The very high F contents would have increased the solubility of Nb, Ta and W in the melt, thus allowing progressive concentration of these elements during magma evolution. Crystallisation of Nb-Ta-W-oxides (W-ixiolite and tantalite-columbite) may have been triggered by separation of cryolithionite, which would have caused F and Li depletion and consequent drop in the solubility of these elements.

  16. Using an Electronic Highlighter to Eliminate the Negative Effects of Pre-Existing, Inappropriate Highlighting

    ERIC Educational Resources Information Center

    Gier, Vicki; Kreiner, David; Hudnell, Jason; Montoya, Jodi; Herring, Daniel

    2011-01-01

    The purpose of the present experiment was to determine whether using an active learning technique, electronic highlighting, can eliminate the negative effects of pre-existing, poor highlighting on reading comprehension. Participants read passages containing no highlighting, appropriate highlighting, or inappropriate highlighting. We hypothesized…

  17. Crystallisation ages in coeval silicic magma bodies: 238U-230Th disequilibrium evidence from the Rotoiti and earthquake flat eruption deposits, Taupo volcanic zone, New Zealand

    USGS Publications Warehouse

    Charlier, B.L.A.; Peate, D.W.; Wilson, C.J.N.; Lowenstern, J. B.; Storey, M.; Brown, S.J.A.

    2003-01-01

    The timescales over which moderate to large bodies of silicic magma are generated and stored are addressed here by studies of two geographically adjacent, successive eruption deposits in the Taupo Volcanic Zone, New Zealand. The earlier, caldera-forming Rotoiti eruption (>100 km3 magma) at Okataina volcano was followed, within months at most, by the Earthquake Flat eruption (??? 10 km3 magma) from nearby Kapenga volcano; both generated nonwelded ignimbrite and coeval widespread fall deposits. The Rotoiti and Earthquake Flat deposits are both crystal-rich high-silica rhyolites, with sparse glass-bearing granitoid fragments also occurring in Rotoiti lag breccias generated during caldera collapse. Here we report 238U-230Th disequilibrium data on whole rocks and mineral separates from representative Rotoiti and Earthquake Flat pumices and the co-eruptive Rotoiti granitoid fragments using TIMS and in situ zircon analyses by SIMS. Multiple-grain zircon-controlled crystallisation ages measured by TIMS from the Rotoiti pumice range from 69??3 ka ( 350 ka, with a pronounced peak at 70-90 ka. The weighted mean of isochrons is 83??14 ka, in accord with the TIMS data. One glass-bearing Rotoiti granitoid clast yielded an age of 57??8 ka by TIMS (controlled by Th-rich phases that, however, are not apparently present in the juvenile pumices). Another glass-bearing Rotoiti granitoid yielded SIMS zircon model ages peaking at 60-90 ka, having a similar age distribution to the pumice. Age data from pumices are consistent with a published 64??4 ka eruptive age (now modified to 62??2 ka), but chemical and/or mineralogical data imply that the granitoid lithics are not largely crystalline Rotoiti rhyolite, but instead represent contemporaneous partly molten intrusions reflecting different sources in their chemistries and mineralogies. Similarly, although the Earthquake Flat eruption immediately followed (and probably was triggered by) the Rotoiti event, age data from juvenile material

  18. Laboratory for Atmospheres 2010 Technical Highlights

    NASA Technical Reports Server (NTRS)

    2011-01-01

    The 2010 Technical Highlights describes the efforts of all members of the Laboratory for Atmospheres. Their dedication to advancing Earth Science through conducting research, developing and running models, designing instruments, managing projects, running field campaigns, and numerous other activities, is highlighted in this report.

  19. Laboratory for Atmospheres 2009 Technical Highlights

    NASA Technical Reports Server (NTRS)

    Cote, Charles E.

    2010-01-01

    The 2009 Technical Highlights describes the efforts of all members of the Laboratory for Atmospheres. Their dedication to advancing Earth Science through conducting research, developing and running models, designing instruments, managing projects, running field campaigns, and numerous other activities, is highlighted in this report.

  20. Laboratory for Atmospheres 2007 Technical Highlights

    NASA Technical Reports Server (NTRS)

    Stewart, Richard W.

    2008-01-01

    The 2007 Technical Highlights describes the efforts of all members of the Laboratory for Atmospheres. Their dedication to advancing Earth Science through conducting research, developing and running models, designing instruments, managing projects, running field campaigns, and numerous other activities, is highlighted in this report.

  1. Laboratory for Atmospheres 2005 Technical Highlights

    NASA Technical Reports Server (NTRS)

    2006-01-01

    The 2005 Technical highlights describes the efforts of all members of the Laboratory for Atmospheres. Their dedication to advancing Earth Science through conducting research, developing and running models, designing instruments, managing projects, running field campaigns, and numerous other activities, is highlighted in this report.

  2. Laboratory for Atmospheres: 2006 Technical Highlights

    NASA Technical Reports Server (NTRS)

    Stewart, Richard W.

    2007-01-01

    The 2006 Technical Highlights describes the efforts of all members of the Laboratory for Atmospheres. Their dedication to advancing Earth science through conducting research, developing and running models, designing instruments, managing projects, running field campaigns, and numerous other activities, are highlighted in this report.

  3. Using Highlighting to Train Attentional Expertise

    PubMed Central

    Roads, Brett; Mozer, Michael C.; Busey, Thomas A.

    2016-01-01

    Acquiring expertise in complex visual tasks is time consuming. To facilitate the efficient training of novices on where to look in these tasks, we propose an attentional highlighting paradigm. Highlighting involves dynamically modulating the saliency of a visual image to guide attention along the fixation path of a domain expert who had previously viewed the same image. In Experiment 1, we trained naive subjects via attentional highlighting on a fingerprint-matching task. Before and after training, we asked subjects to freely inspect images containing pairs of prints and determine whether the prints matched. Fixation sequences were automatically scored for the degree of expertise exhibited using a Bayesian discriminative model of novice and expert gaze behavior. Highlighted training causes gaze behavior to become more expert-like not only on the trained images but also on transfer images, indicating generalization of learning. In Experiment 2, to control for the possibility that the increase in expertise is due to mere exposure, we trained subjects via highlighting of fixation sequences from novices, not experts, and observed no transition toward expertise. In Experiment 3, to determine the specificity of the training effect, we trained subjects with expert fixation sequences from images other than the one being viewed, which preserves coarse-scale statistics of expert gaze but provides no information about fine-grain features. Observing at least a partial transition toward expertise, we obtain only weak evidence that the highlighting procedure facilitates the learning of critical local features. We discuss possible improvements to the highlighting procedure. PMID:26744839

  4. Using Highlighting to Train Attentional Expertise.

    PubMed

    Roads, Brett; Mozer, Michael C; Busey, Thomas A

    2016-01-01

    Acquiring expertise in complex visual tasks is time consuming. To facilitate the efficient training of novices on where to look in these tasks, we propose an attentional highlighting paradigm. Highlighting involves dynamically modulating the saliency of a visual image to guide attention along the fixation path of a domain expert who had previously viewed the same image. In Experiment 1, we trained naive subjects via attentional highlighting on a fingerprint-matching task. Before and after training, we asked subjects to freely inspect images containing pairs of prints and determine whether the prints matched. Fixation sequences were automatically scored for the degree of expertise exhibited using a Bayesian discriminative model of novice and expert gaze behavior. Highlighted training causes gaze behavior to become more expert-like not only on the trained images but also on transfer images, indicating generalization of learning. In Experiment 2, to control for the possibility that the increase in expertise is due to mere exposure, we trained subjects via highlighting of fixation sequences from novices, not experts, and observed no transition toward expertise. In Experiment 3, to determine the specificity of the training effect, we trained subjects with expert fixation sequences from images other than the one being viewed, which preserves coarse-scale statistics of expert gaze but provides no information about fine-grain features. Observing at least a partial transition toward expertise, we obtain only weak evidence that the highlighting procedure facilitates the learning of critical local features. We discuss possible improvements to the highlighting procedure. PMID:26744839

  5. Highlight area inpainting guided by illumination model

    NASA Astrophysics Data System (ADS)

    Wang, Yifan; Jiang, Zhiguo; Shi, Jun

    2014-01-01

    In this paper, we proposed a two-step algorithm based on the combination of the exemplar-based algorithm and the illumination model to deal with specular images, especially those contain saturated pixels in the highlight areas. First the proposed modified exemplar-based algorithm is employed to process the unsaturated specular pixels under the supervision of illumination model. Then we inpaint the rest regions in which the pixels are saturated with original exemplar-based algorithm to obtain the final result. Experimental results demonstrate that the proposed algorithm performs better on the images with saturated pixels in the highlight areas compared with classical highlight removal and image inpainting algorithms.

  6. Are arc-type rocks the products of magma crystallisation? Observations from a simple oceanic arc volcano: Raoul Island, Kermadec Arc, SW Pacific

    NASA Astrophysics Data System (ADS)

    Smith, Ian E. M.; Stewart, Robert B.; Price, Richard C.; Worthington, Timothy J.

    2010-02-01

    Raoul Island is the emergent summit of a large intra-oceanic strato-volcano in what is globally one of the simplest of subduction settings. In this simple setting erupted magmas span the compositional range from basalt to dacite but none have the high Mg-numbers and high Ni and Cr expected of primitive mantle-derived melts. The lavas range from aphyric to highly porphyritic and are characterised by phenocryst assemblages dominated by plagioclase accompanied by clinopyroxene, olivine, orthopyroxene and spinel. Phenocryst core compositions and zoning profiles are remarkably uniform irrespective of total phenocryst content or geochemical composition, indicating a decoupling of melt and crystal components in the system. A consistent model for the Raoul magmatic system is that primitive high-Mg magma generated in a melt column within the underlying mantle wedge is transformed into a series of derivative low-Mg magmas by fractional crystallisation within the lower crust. Low-Mg magma accumulates variable quantities of crystal cargo as it ascends toward the surface through a crystal mush zone. These processes are essentially those that characterise continental subduction-related magmatic systems but differ only in the absence of an evolved crustal component.

  7. Physicochemical properties and crystallisation behaviour of bakery shortening produced from stearin fraction of palm-based diacyglycerol blended with various vegetable oils.

    PubMed

    Latip, Razam Ab; Lee, Yee-Ying; Tang, Teck-Kim; Phuah, Eng-Tong; Tan, Chin-Ping; Lai, Oi-Ming

    2013-12-15

    The stearin fraction of palm-based diacylglycerol (PDAGS) was produced from dry fractionation of palm-based diacylglycerol (PDAG). Bakery shortening blends were produced by mixing PDAGS with either palm mid fraction, PMF (PDAGS/PMF), palm olein, POL(PDAGS/POL) or sunflower oil, SFO (PDAGS/SFO) at PDAGS molar fraction of XPDAGS=0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%. The physicochemical results obtained indicated that C16:0 and C18:1 were the dominant fatty acids for PDAGS/PMF and PDAGS/POL, while C18:1 and C18:2 were dominant in the PDAGS/SFO mixtures. SMP and SFC of the PDAGS were reduced with the addition of PMF, POL and SFO. Binary mixtures of PDAGS/PMF had better structural compatibility and full miscibility with each other. PDAGS/PMF and PDAGS/SFO crystallised in β'+β polymorphs in the presence of 0.4-0.5% PDAGS while PDAGS/POL resulted in β polymorphs crystal. The results gave indication that PDAGS: PMF at 50%:50% and 60%:40% (w/w) were the most suitable fat blend to be used as bakery shortening. PMID:23993569

  8. Highlights from NNSA's Decade of Success

    SciTech Connect

    2010-04-28

    On April 28, 2010, the National Nuclear Security Administration celebrated its 10-year anniversary with a series of events aimed at highlighting a decade of success across the nuclear security enterprise. This slideshow features images from the past 10 years.

  9. EuroEcho-Imaging 2015: highlights.

    PubMed

    Magne, Julien; Popescu, Bogdan A; Cosyns, Bernard; Donal, Erwan; Miller, Owen; Neglia, Danilo; Plein, Sven; Lancellotti, Patrizio; Habib, Gilbert

    2016-06-01

    The annual meeting of the European Association of Cardiovascular Imaging, EuroEcho-Imaging, was held in Seville, Spain, in December 2015. In the present paper, we present a summary of the 'Highlights' session. PMID:27099280

  10. Highlights of the 2009 Hurricane Season

    NASA Video Gallery

    Picture yourself sitting in space watching the highlights of the 2009's Atlantic Ocean hurricane season in fast-forward. This latest animation from NASA and the National Oceanic and Atmospheric Adm...

  11. Highlights from NNSA's Decade of Success

    ScienceCinema

    None

    2010-09-01

    On April 28, 2010, the National Nuclear Security Administration celebrated its 10-year anniversary with a series of events aimed at highlighting a decade of success across the nuclear security enterprise. This slideshow features images from the past 10 years.

  12. Display format, highlight validity, and highlight method: Their effects on search performance

    NASA Technical Reports Server (NTRS)

    Donner, Kimberly A.; Mckay, Tim D.; Obrien, Kevin M.; Rudisill, Marianne

    1991-01-01

    Display format and highlight validity were shown to affect visual display search performance; however, these studies were conducted on small, artificial displays of alphanumeric stimuli. A study manipulating these variables was conducted using realistic, complex Space Shuttle information displays. A 2x2x3 within-subjects analysis of variance found that search times were faster for items in reformatted displays than for current displays. Responses to valid applications of highlight were significantly faster than responses to non or invalidly highlighted applications. The significant format by highlight validity interaction showed that there was little difference in response time to both current and reformatted displays when the highlight validity was applied; however, under the non or invalid highlight conditions, search times were faster with reformatted displays. A separate within-subject analysis of variance of display format, highlight validity, and several highlight methods did not reveal a main effect of highlight method. In addition, observed display search times were compared to search time predicted by Tullis' Display Analysis Program. Benefits of highlighting and reformatting displays to enhance search and the necessity to consider highlight validity and format characteristics in tandem for predicting search performance are discussed.

  13. Education at a Glance 2012: Highlights

    ERIC Educational Resources Information Center

    OECD Publishing (NJ3), 2012

    2012-01-01

    "Education at a Glance 2012: Highlights" offers a reader-friendly introduction to the Organisation for Economic Cooperation and Development's (OECD's) collection of internationally comparable data on education. As the name suggests, it is derived from "Education at a Glance 2012", the OECD's flagship compendium of education statistics. However, it…

  14. PARTICULATE CONTROL HIGHLIGHTS: FINE PARTICLE SCRUBBER RESEARCH

    EPA Science Inventory

    The report gives highlights of fine particle scrubber research performed by, or under the direction of, EPA's Industrial Environmental Research Laboratory (IERL-RTP) at Research Triangle Park, North Carolina. The U.S. EPA has been actively involved in research and development in ...

  15. LibTech Highlights from ALA Midwinter

    ERIC Educational Resources Information Center

    Hane, Paula J.

    2009-01-01

    Despite lower attendance than in the past and blustery, cold weather, the American Library Association's Midwinter Meeting in Denver in January offered lots of news from industry vendors and lots of opportunities to discuss important issues and trends. In this report, the author highlights some of the most important product announcements with a…

  16. The Nation's Report Card: Science Highlights 2000.

    ERIC Educational Resources Information Center

    Education Statistics Quarterly, 2001

    2001-01-01

    Presents highlights from the National Assessment of Educational Progress (NAEP) 2000 Science Assessment, including average scores and achievement-level performance at the national and state levels. Results show no change in national average scores at grades 4 and 8 and a decline at grade 12, with few changes overall in students' 2000 achievement…

  17. Brookhaven highlights - Brookhaven National Laboratory 1995

    SciTech Connect

    1996-09-01

    This report highlights research conducted at Brookhaven National Laboratory in the following areas: alternating gradient synchrotron; physics; biology; national synchrotron light source; department of applied science; medical; chemistry; department of advanced technology; reactor; safety and environmental protection; instrumentation; and computing and communications.

  18. Brookhaven highlights, October 1979-September 1980

    SciTech Connect

    Not Available

    1980-01-01

    Highlights are given for the research areas of the Brookhaven National Laboratory. These areas include high energy physics, physics and chemistry, life sciences, applied energy science (energy and environment, and nuclear energy), and support activities (including mathematics, instrumentation, reactors, and safety). (GHT)

  19. Highlights from Education at a Glance 2010

    ERIC Educational Resources Information Center

    OECD Publishing (NJ3), 2010

    2010-01-01

    "Highlights from Education at a Glance 2010" is a companion publication to the OECD's flagship compendium of education statistics, Education at a Glance. It provides easily accessible data on key topics in education today, including: education levels and student numbers, economic and social benefits of education, education spending, the school…

  20. Highlights on DESD Progress to Date

    ERIC Educational Resources Information Center

    United Nations Educational, Scientific and Cultural Organization (UNESCO), 2007

    2007-01-01

    This brief report, delivered after the completion of the 1st year of the United Nations (UN) Decade of Education for Sustainable Development (DESD) (2005-2014), highlights the recent developments regarding the Decade (2005). It reports on the documents prepared, the regional and national launches of the Decade held so far and presents relevant…

  1. The Nation's Report Card: Mathematics Highlights, 2003.

    ERIC Educational Resources Information Center

    National Center for Education Statistics (ED), Washington, DC.

    This issue of The Nation's Report Card highlights mathematics in 2003. It includes sections on Average Scale Scores, Students Reaching NAEP Achievement Levels, Percentile Results, 2003 Assessment Design, State Results, Subgroup Results, Sample Mathematics Questions, Technical Notes, Additional Data Tables, and NAEP on the Web. (AMT)

  2. Highlights from AQMEII Phase 2 & Next Steps

    EPA Science Inventory

    We present highlights of the results obtained in the second phase of the Air Quality Model Evaluation International Initiative (AQMEII) that was completed in May 2014. Activities in this phase were focused on the application and evaluation of coupled meteorology-chemistry models ...

  3. EM international activities. February 1997 highlights

    SciTech Connect

    1997-02-01

    EM International Highlights is a brief summary of on-going international projects within the Department of Energy`s Office of Environmental Management (EM). This document contains sections on: Global Issues, activities in Western Europe, activities in central and Eastern Europe, activities in Russia, activities in Asia and the Pacific Rim, activities in South America, activities in North America, and International Organizations.

  4. Education at a Glance 2011: Highlights

    ERIC Educational Resources Information Center

    OECD Publishing (NJ1), 2011

    2011-01-01

    "Education at a Glance 2011: Highlights" offers a reader-friendly introduction to the Organisation for Economic Cooperation and Development's (OECD's) collection of internationally comparable data on education. As the name suggests, it is derived from "Education at a Glance 2011", the OECD's flagship compendium of education statistics. However, it…

  5. Highlighting relatedness promotes prosocial motives and behavior.

    PubMed

    Pavey, Louisa; Greitemeyer, Tobias; Sparks, Paul

    2011-07-01

    According to self-determination theory, people have three basic psychological needs: relatedness, competence, and autonomy. Of these, the authors reasoned that relatedness need satisfaction is particularly important for promoting prosocial behavior because of the increased sense of connectedness to others that this engenders. In Experiment 1, the authors manipulated relatedness, autonomy, competence, or gave participants a neutral task, and found that highlighting relatedness led to higher interest in volunteering and intentions to volunteer relative to the other conditions. Experiment 2 found that writing about relatedness experiences promoted feelings of connectedness to others, which in turn predicted greater prosocial intentions. Experiment 3 found that relatedness manipulation participants donated significantly more money to charity than did participants given a neutral task. The results suggest that highlighting relatedness increases engagement in prosocial activities and are discussed in relation to the conflict and compatibility between individual and social outcomes. PMID:21521720

  6. 2000 Guidance, Navigation, and Control Highlights

    NASA Technical Reports Server (NTRS)

    Polites, Michael E.

    2000-01-01

    This article summarizes the highlights of recent events and developments in guidance, navigation, and control in space, aircraft, and weapons. This article is about 1,200 words long. Information for the article was collected from other NASA centers, DoD, and industry. All information was previously cleared by the originating organizations. Information for the article was also gathered from Aviation Week and Space Technology, Space News, and similar sources.

  7. Science Highlights from the Cassini magnetometer instrument

    NASA Astrophysics Data System (ADS)

    Dougherty, Michele

    2014-05-01

    The Cassini dual technique magnetometer instrument has been taking data in the Saturn system for the last 10 years. Science highlights encompass topics including the magnetosphere and its aurora, the internal dynamo magnetic field of Saturn, the icy satellites and Enceladus in particular, as well as the large moon Titan. The science discoveries will be described as well as important science observations yet to be made in the remaining 4 years of the mission.

  8. 1999 Guidance, Navigation, and Control Highlights

    NASA Technical Reports Server (NTRS)

    Polites, Michael E.

    1999-01-01

    This article summarizes the highlights of recent events and developments in guidance, navigation, and control in space, aircraft, and weapons. This article is about 1,200 words long. Information for the article was collected from other NASA Centers, DoD, and industry. All information was previously cleared by the originating organizations. Information for the article was also gathered from Aviation Week and Space Technology, Space News, and similar sources.

  9. Recent Highlights from the ISOLDE Facility

    NASA Astrophysics Data System (ADS)

    Johnston, K.

    2015-11-01

    The ISOLDE facility is CERN's longest running experiment. In its 45 years of operation it has become the world's most comprehensive radioactive-isotope factory. Now capable of delivering more than 1000 isotopes from 70 chemical elements, ISOLDE supports a wide and diverse physics programme. This short article summarizes some of the recent highlights from this programme in the areas of nuclear physics, medicine and biology.

  10. STS-111 Flight Day 10 Highlights Replay

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The most important highlight of flight day 10 of STS-111 was the undocking of the Leonardo Multi Purpose Logistical Module (MPLM) from the Unity module of the International Space Station (ISS). The undocking is shown, as is Leonardo resting in Endeavour's payload bay. The video also includes an interview, and footage of the West Africa and the Atlantic Ocean, Gibraltar and the Mediterranean Sea, Italy, Mexico and the Pacific Ocean, Hispanola, an unknown land mass, and unknown mountains.

  11. STS-109 Mission Highlights Resource Tape

    NASA Astrophysics Data System (ADS)

    2002-05-01

    This video, Part 3 of 4, shows the activities of the STS-109 crew (Scott Altman, Commander; Duane Carey, Pilot; John Grunsfeld, Payload Commander; Nancy Currie, James Newman, Richard Linnehan, Michael Massimino, Mission Specialists) during flight days 6 and 7. The activities from other flight days can be seen on 'STS-109 Mission Highlights Resource Tape' Part 1 of 4 (internal ID 2002139471), 'STS-109 Mission Highlights Resource Tape' Part 2 of 4 (internal ID 2002137664), and 'STS-109 Mission Highlights Resource Tape' Part 4 of 4 (internal ID 2002137577). Flight day 6 features a very complicated EVA (extravehicular activity) to service the HST (Hubble Space Telescope). Astronauts Grunsfeld and Linnehan replace the HST's power control unit, disconnecting and reconnecting 36 tiny connectors. The procedure includes the HST's first ever power down. The cleanup of spilled water from the coollant system in Grunsfeld's suit is shown. The pistol grip tool, and two other space tools are also shown. On flight day 7, Newman and Massimino conduct an EVA. They replace the HST's FOC (Faint Object Camera) with the ACS (Advanced Camera for Surveys). The video ends with crew members playing in the shuttle's cabin with a model of the HST.

  12. STS-111 Mission Highlights Resource Tape

    NASA Astrophysics Data System (ADS)

    2002-08-01

    This video, Part 1 of 4, shows the activities of the STS-111 crew (Kenneth Cockrell, Commander; Paul Lockhart, Pilot; Franklin Chang-Diaz, Phillipe Perrin, Mission Specialists) during flight days 1 through 4. Also shown are the incoming Expedition 5 (Valeri Korzun, Commander; Peggy Whitson, NASA ISS Science Officer; Sergei Treschev, Flight Engineer) and outgoing Expedition 4 (Yuri Onufriyenko, Commander; Carl Walz, Daniel Bursch, Flight Engineers) crews of the ISS (International Space Station). The activities from other flight days can be seen on 'STS-111 Mission Highlights Resource Tape' Part 2 of 4 (internal ID 2002139469), 'STS-111 Mission Highlights Resource Tape' Part 3 of 4 (internal ID 2002139468), and 'STS-111 Mission Highlights Resource Tape' Part 4 of 4 (internal ID 2002139474). The primary activity of flight day 1 is the launch of Space Shuttle Endeavour. The crew is seen before the launch at a meal and suit-up, and some pre-flight procedures are shown. Perrin holds a sign with a personalized message. The astronauts communicate with Mission Control extensively after launch, and an inside view of the shuttle cabin is shown. The replays of the launch include close-ups of the nozzles at liftoff, and the fall of the solid rocket boosters and the external fuel tank. Flight day 2 shows footage of mainland Asia at night, and daytime views of the eastern United States and Lake Michigan. Flight day three shows the Endeavour orbiter approaching and docking with the ISS. After the night docking, the crews exchange greetings, and a view of the Nile river and Egypt at night is shown. On flight day 4, the MPLM (Multi-Purpose Logistics Module) Leonardo was temporarily transferred from Endeavour's payload bay to the ISS.

  13. STS-109 Mission Highlights Resource Tape

    NASA Astrophysics Data System (ADS)

    2002-05-01

    This video, Part 1 of 4, shows the activities of the STS-109 crew (Scott Altman, Commander; Duane Carey, Pilot; John Grunsfeld, Payload Commander; Nancy Currie, James Newman, Richard Linnehan, Michael Massimino, Mission Specialists) during flight days 1 through 3. The activities from other flight days can be seen on 'STS 109 Mission Highlights Resource Tape' Part 2 of 4 (internal ID 2002137664), 'STS 109 Mission Highlights Resource Tape' Part 3 of 4 (internal ID 2002139471), and 'STS-109 Mission Highlights Resource Tape' Part 4 of 4 (internal ID 2002137577). The main activity recorded during flight day 1 is the liftoff of Columbia. Attention is given to suit-up, boarding, and pre-flight procedures. The pre-launch crew meal has no sound. The crew members often wave to the camera before liftoff. The jettisoning of the solid rocket boosters is shown, and the External Tank is seen as it falls to Earth, moving over African dunes in the background. There are liftoff replays, including one from inside the cockpit. The opening of the payload bay doors is seen from the rear of the shuttle's cockpit. The footage from flight day 2 shows the Flight Support System for bearthing the HST (Hubble Space Telescope). Crew preparations for the bearthing are shown. Flight day 3 shows the tracking of and approach to the HST by Columbia, including orbital maneuvers, the capture of the HST, and its lowering onto the Flight Support System. Many views of the HST are shown, including one which reveals an ocean and cloud background as the HST retracts a solar array.

  14. STS-109 Mission Highlights Resource Tape

    NASA Astrophysics Data System (ADS)

    2002-05-01

    This video, Part 4 of 4, shows footage of crew activities from flight days 8 through 12 of STS-109. The crew included: Scott Altman, Commander; Duane Carey, Pilot; John Grunsfeld, Payload Commander; Nancy Currie, Richard Linnehan, James Newman, Michael Massimino, Mission Speicalists. The activities from other flights days can be seen on 'STS-109 Mission Highlights Resource Tape' Part 1 of 4 (internal ID 2002139471), 'STS-109 Mission Highlights Resource Tape' Part 2 of 4 (internal ID 2002137664), and 'STS-109 Mission Highlights Resource Tape' Part 3 of 4 (internal ID 2002139476). The primary activity on flight day 8 was an EVA (extravehicular activity) by Grunsfeld and Linnehan to install a cryocooler and radiator for the NICMOS (Near Infrared Camera and Multi-Object Spectrometer) on the HST (Hubble Space Telescope). Before returning to Columbia's airlock, the astronauts, with a cloudy background, hold onto the orbiter and offer their thoughts on the significance of their mission, the HST, and spaceflight. Footage from flight day 9 includes the grappling, unbearthing, and deployment of the HST from Columbia, and the crew coordinating and videotaping Columbia's departure. Flight day 10 was a relatively inactive day, and flight day 11 includes a checkout of Columbia's aerodynamic surfaces. Columbia landed on flight day 12, which is covered by footage of the crew members speaking during reentry, and their night landing, primarily shown through the orbiter's head-up display. The video includes numerous views of the HST, as well as views of the the Galapagos Islands, Madagascar, and Southern Africa with parts of the Atlantic, Indian, and Pacific Oceans, and part of the coast of Chile. The pistol grip space tool is shown in use, and the crew answers two messages from the public, including a message to Massimino from the Fire Department of New York.

  15. STS-109 Mission Highlights Resource Tape

    NASA Astrophysics Data System (ADS)

    2002-05-01

    This video, Part 2 of 4, shows the activities of the STS-109 crew (Scott Altman, Commander; Duane Carey, Pilot; John Grunsfeld, Payload Commander; Nancy Currie, James Newman, Richard Linnehan, Michael Massimino, Mission Specialists) during flight days 4 and 5. The activities from other flights days can be seen on 'STS-109 Mission Highlights Resource Tape' Part 1 of 4 (internal ID 2002139471), 'STS-109 Mission Highlights Resource Tape' Part 3 of 4 (internal ID 2002139476), and 'STS-109 Mission Highlights Resource Tape' Part 4 of 4 (internal ID 2002137577). The primary activities during these days were EVAs (extravehicular activities) to replace two solar arrays on the HST (Hubble Space Telescope). Footage from flight day 4 records an EVA by Grunsfeld and Linnehan, including their exit from Columbia's payload bay airlock, their stowing of the old HST starboard rigid array on the rigid array carrier in Columbia's payload bay, their attachment of the new array on HST, the installation of a new starboard diode box, and the unfolding of the new array. The pistol grip space tool used to fasten the old array in its new location is shown in use. The video also includes several shots of the HST with Earth in the background. On flight day 5 Newman and Massimino conduct an EVA to change the port side array and diode box on HST. This EVA is very similar to the one on flight day 4, and is covered similarly in the video. A hand operated ratchet is shown in use. In addition to a repeat of the previous tasks, the astronauts change HST's reaction wheel assembly, and because they are ahead of schedule, install installation and lubricate an instrument door on the telescope. The Earth views include a view of Egypt and Israel, with the Nile River, Red Sea, and Mediterranean Sea.

  16. Highlights in the study of exoplanet atmospheres

    NASA Astrophysics Data System (ADS)

    Burrows, Adam S.

    2014-09-01

    Exoplanets are now being discovered in profusion. To understand their character, however, we require spectral models and data. These elements of remote sensing can yield temperatures, compositions and even weather patterns, but only if significant improvements in both the parameter retrieval process and measurements are made. Despite heroic efforts to garner constraining data on exoplanet atmospheres and dynamics, reliable interpretation has frequently lagged behind ambition. I summarize the most productive, and at times novel, methods used to probe exoplanet atmospheres; highlight some of the most interesting results obtained; and suggest various broad theoretical topics in which further work could pay significant dividends.

  17. Langley aeronautics and space test highlights, 1984

    NASA Technical Reports Server (NTRS)

    1984-01-01

    The role of the Langley Research Center is to perform basic and applied research necessary for the advancement of aeronautics and space flight, to generate new and advanced concepts for the accomplishment of related national goals, and to provide research advice, technological support, and assistance to other NASA installations, other government agencies, and industry. Some of the significant tests which were performed during calendar year 1984 in Langley test facilities are highlighted. The broad range of the research and technology activities at the Langley Research Center and the contributions of this work toward maintaining United States leadership in aeronautics and space research are illustrated.

  18. Fermi GBM: Highlights from the First Year

    NASA Technical Reports Server (NTRS)

    Wilson-Hodge, Colleen A.

    2009-01-01

    The Fermi Gamma ray Burst Monitor is an all-sky instrument sensitive to photons from about 8 keV to 40 MeV. I will summarize highlights from the first year, including triggered observations of gamma ray bursts, soft gamma ray repeaters, and terrestrial gamma flashes, and observations in the continuous data of X-ray binaries and accreting X-ray pulsars. GBM provides complementary observations to Swift/BAT, observing many of the same sources, but over a wider energy range.

  19. Highlights in Astronomy Education, Outreach, and Heritage

    NASA Astrophysics Data System (ADS)

    Hemenway, Mary

    2015-08-01

    Short talks and a panel discussion by members of the leadership of Division C will highlight important work that has occurred since the last General Assembly. Although a small portion of the session will cover administrative matters of the Division, Commissions, and Working Groups, the focus will be on accomplishments in the broad fields of education, outreach, and heritage. The purpose of the session is to not only inform the audience about a sample of cutting edge projects and methodologies in our fields, but to invite participants to become more involved.

  20. STS-111 Flight Day 4 Highlights Replay

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The most significant highlights of flight day 4 of STS-111 are the lifting of the Leonardo Multi Purpose Logistics Module (MPLM) out of Endeavour's payload bay, and its temporary attachment to the Unity module of the International Space Station (ISS). The lifting and attachment are shown. Also shown is the testing of cameras on the CANADARM2 robotic arm on the ISS, an ISS extravehicular activity (EVA) suit, and an interview with the outgoing Expedition 4 crew of the ISS. Earth views include the ISS and Earth limb, and cloud formations.

  1. Highlights in the study of exoplanet atmospheres.

    PubMed

    Burrows, Adam S

    2014-09-18

    Exoplanets are now being discovered in profusion. To understand their character, however, we require spectral models and data. These elements of remote sensing can yield temperatures, compositions and even weather patterns, but only if significant improvements in both the parameter retrieval process and measurements are made. Despite heroic efforts to garner constraining data on exoplanet atmospheres and dynamics, reliable interpretation has frequently lagged behind ambition. I summarize the most productive, and at times novel, methods used to probe exoplanet atmospheres; highlight some of the most interesting results obtained; and suggest various broad theoretical topics in which further work could pay significant dividends. PMID:25230656

  2. Introducing Open Highlights: Highlighting Open Access Research from PLOS and Beyond.

    PubMed

    2016-07-01

    PLOS Biology announces a new article type, Open Highlights, which uses a recent research article to nucleate a short synthesis of up to ten related research articles from other PLOS journals and from the wider Open Access corpus. PMID:27400228

  3. Physical Sciences 2007 Science & Technology Highlights

    SciTech Connect

    Hazi, A U

    2008-04-07

    The Physical Sciences Directorate applies frontier physics and technology to grand challenges in national security. Our highly integrated and multidisciplinary research program involves collaborations throughout Lawrence Livermore National Laboratory, the National Nuclear Security Administration, the Department of Energy, and with academic and industrial partners. The Directorate has a budget of approximately $150 million, and a staff of approximately 350 employees. Our scientists provide expertise in condensed matter and high-pressure physics, plasma physics, high-energy-density science, fusion energy science and technology, nuclear and particle physics, accelerator physics, radiation detection, optical science, biotechnology, and astrophysics. This document highlights the outstanding research and development activities in the Physical Sciences Directorate that made news in 2007. It also summarizes the awards and recognition received by members of the Directorate in 2007.

  4. STS-114 Flight Day 2 Highlights

    NASA Technical Reports Server (NTRS)

    2005-01-01

    Video coverage of NASA's Return to Flight continues with highlights from Day 2 of STS-114. After a wake-up song from Mission Control Center, the crew of Space Shuttle Discovery (Commander Eileen Collins, Pilot James Kelly, Mission Specialists Soichi Noguchi, Stephen Robinson, Andrew Thomas, Wendy Lawrence, and Charles Camarda) inspects the orbiter for damage using a camera on the Shuttle Remote Manipulator System (SRMS). The SRMS, a robot arm, extends its length by grappling the new Orbiter Boom Sensor System, in order to image Discovery's wing leading edges and the underside of its nose. After the boom is stowed in the payload bay, the top and sides of the crew cabin are then imaged, including the Reaction Control System jets. The Shuttle's Ku-band antenna is then deployed. The video includes scenes of the payload bay contents, and crew members on the flight deck.

  5. STS-67 mission highlights resource tape

    NASA Astrophysics Data System (ADS)

    Welch, Chuck

    1995-05-01

    The Space Shuttle Mission, STS-67, is highlighted in this video. Flight crew (Stephen S. Oswald (Commander), William G. Gregory (Pilot), Tamara E. Jernigan, Wendy B. Lawrence, John M. Grunfeld (Mission Specialists), Samuel T. Durrance, and Ronald A. Parise (Payload Specialists)) prelaunch and launch activities, EVA activities with payload deployment and retrieval (ASTRO-2 and WUPPE (Wisconsin Ultraviolet Photo Polarimeter Experiment)), spaceborne experiments (astronomical observation and data collection, protein crystal growth, and human physiological processes), and pre-reentry activities are shown. There are astronomical telescopic observation from the two telescopes in the payload, the Hopkins Ultraviolet Telescope and the Ultraviolet Imaging Telescope, of Io and of globular clusters, and their emission spectra is collected via a spectrometer. Earth view film and photography is shown, which includes lightning on terrestrial surfaces, cyclone activity, and cloud cover.

  6. FY 1996 Congressional budget request: Budget highlights

    SciTech Connect

    Not Available

    1995-02-01

    The FY 1996 budget presentation is organized by the Department`s major business lines. An accompanying chart displays the request for new budget authority. The report compares the budget request for FY 1996 with the appropriated FY 1995 funding levels displayed on a comparable basis. The FY 1996 budget represents the first year of a five year plan in which the Department will reduce its spending by $15.8 billion in budget authority and by $14.1 billion in outlays. FY 1996 is a transition year as the Department embarks on its multiyear effort to do more with less. The Budget Highlights are presented by business line; however, the fifth business line, Economic Productivity, which is described in the Policy Overview section, cuts across multiple organizational missions, funding levels and activities and is therefore included in the discussion of the other four business lines.

  7. Pulsars, PTAs, and PALFA: Highlights and Opportunities

    NASA Astrophysics Data System (ADS)

    Scholz, Paul A.

    2015-08-01

    The detection of gravitational waves with nanohertz frequencies from SMBHs in merging galaxies, either a single source or a background, is greatly aided by increasing the sensitivity of pulsar timing arrays (PTAs). Increasing the number of millisecond pulsars in PTAs is one of the best ways to enhance their sensitivity. Therefore searches for new millisecond pulsars are absolutely essential to the detection of gravitational waves from merging galaxies. I will review the status of current pulsar search efforts and how they have contributed to PTAs. I will then present some of the recent highlights of the PALFA survey. Using the PALFA survey as a case study, I will outline the current challenges faced by pulsar searches, including RFI and a large number of false positives, and potential solutions to those issues.

  8. AGILE Data Center and AGILE science highlights

    NASA Astrophysics Data System (ADS)

    Pittori, C.

    2013-06-01

    AGILE is a scientific mission of the Italian Space Agency (ASI) with INFN, INAF e CIFS participation, devoted to gamma-ray astrophysics. The satellite is in orbit since April 23rd, 2007. Gamma-ray astrophysics above 100 MeV is an exciting field of astronomical sciences that has received a strong impulse in recent years. Despite the small size and budget, AGILE produced several important scientific results, among which the unexpected discovery of strong and rapid gamma-ray flares from the Crab Nebula. This discovery won to the AGILE PI and the AGILE Team the prestigious Bruno Rossi Prize for 2012, an international recognition in the field of high energy astrophysics. We present here the AGILE data center main activities, and we give an overview of the AGILE scientific highlights after 5 years of operations.

  9. Country break-out session highlights.

    PubMed

    Fazekas, Franz; Gehring, Klaus; Gallo, Paolo; Lebrun-Frénay, Christine; Moral, Ester; Myhr, Kjell-Morten

    2015-01-01

    Individuals with multiple sclerosis (MS) spasticity present a wide range of symptoms and disability levels that are frequently challenging to manage. At the MS Experts Summit 2015, five country breakout sessions were conducted in parallel, and mainly in the native language, to examine various aspects about the management of treatment-resistant MS spasticity. Topics covered included video documentation of MS spasticity management (Germany), use of cannabinoid medicines in daily practice (Italy), multidisciplinary approach to MS spasticity care (France), titration and adherence to treatments for MS spasticity (Spain) and management of MS symptoms (Norway/Rest of World). For the benefit of all attendees, session highlights were collated and presented in a Plenary Session which is summarized herein. PMID:26611270

  10. STS-66 Mission Highlights Resource Tape

    NASA Technical Reports Server (NTRS)

    1995-01-01

    This video contains the mission highlights of the STS-66 Space Shuttle Atlantis Mission in November 1994. Astronauts included: Don McMonagle (Mission Commander), Kurt Brown, Ellen Ochoa (Payload Commander), Joe Tanner, Scott Parazynski, and Jean-Francois Clervoy (collaborating French astronaut). Footage includes: pre-launch suitup, entering Space Shuttle, countdown and launching of Shuttle, EVA activities (ATLAS-3, CRISTA/SPAS, SSBUV/A, ESCAPE-2), on-board experiments dealing with microgravity and its effects, protein crystal growth experiments, daily living and sleeping compartment footage, earthviews of various meteorological processes (dust storms, cloud cover, ocean storms), pre-landing and land footage (both from inside the Shuttle and from outside with long range cameras), and tracking and landing shots from inside Mission Control Center. Included is air-to-ground communication between Mission Control and the Shuttle. This Shuttle was the last launch of 1994.

  11. Langley aeronautics and space test highlights, 1983

    NASA Technical Reports Server (NTRS)

    1984-01-01

    The role of the Langley Research Center is to perform basic and applied research necessary for the advancement of aeronautics and space flight, to generate new and advanced concepts for the accomplishment of related national goals, and to provide research advice, technological support, and assistance to other NASA installations, other government agencies, and industry. Some of the significant tests which were performed during calendar year 1983 in Langley test facilities, a number of which are unique in the world are highlighted. Both the broad range of the research and technology activities at the Langley Research Center and the contributions of this work toward maintaining United States leadership in aeronautics and space research are illustrated.

  12. Research highlights: impacts of microplastics on plankton.

    PubMed

    Lin, Vivian S

    2016-02-01

    Each year, millions of metric tons of the plastic produced for food packaging, personal care products, fishing gear, and other human activities end up in lakes, rivers, and the ocean. The breakdown of these primary plastics in the environment results in microplastics, small fragments of plastic typically less than 1-5 mm in size. These synthetic particles have been detected in all of the world's oceans and also in many freshwater systems, accumulating in sediment, on shorelines, suspended in surface waters, and being ingested by plankton, fish, birds, and marine mammals. While the occurrence of plastics in surface waters has been surveyed in a number of studies, the impacts of microplastics on marine organisms are still being elucidated. This highlight features three recent publications that explore the interactions of microplastics with planktonic organisms to clarify the effects of these pollutants on some of the ocean's smallest and most important inhabitants. PMID:26829584

  13. STS-114 Flight Day 5 Highlights

    NASA Technical Reports Server (NTRS)

    2005-01-01

    Highlights of Day 5 of the STS-114 Return to Flight mission (Commander Eileen Collins, Pilot James Kelly, Mission Specialists Soichi Noguchi, Stephen Robinson, Andrew Thomas, Wendy Lawrence, and Charles Camarda) include video coverage of an extravehiclular activity (EVA) by Noguchi and Robinson. The other crew members of Discovery are seen on the flight deck and mid-deck helping the astronauts to suit-up. The objectives of the EVA are to test repair techniques on sample tiles in the shuttle's payload bay, to repair electrical equipment for a gyroscope on the International Space Station (ISS), and to install a replacement GPS antenna on the ISS. Noguchi and Robinson use a caulk gun and a putty knife to repair the sample tiles. The video contains several Earth views, including one of Baja California.

  14. Research highlights: microfluidics meets big data.

    PubMed

    Tseng, Peter; Weaver, Westbrook M; Masaeli, Mahdokht; Owsley, Keegan; Di Carlo, Dino

    2014-03-01

    In this issue we highlight a collection of recent work in which microfluidic parallelization and automation have been employed to address the increasing need for large amounts of quantitative data concerning cellular function--from correlating microRNA levels to protein expression, increasing the throughput and reducing the noise when studying protein dynamics in single-cells, and understanding how signal dynamics encodes information. The painstaking dissection of cellular pathways one protein at a time appears to be coming to an end, leading to more rapid discoveries which will inevitably translate to better cellular control--in producing useful gene products and treating disease at the individual cell level. From these studies it is also clear that development of large scale mutant or fusion libraries, automation of microscopy, image analysis, and data extraction will be key components as microfluidics contributes its strengths to aid systems biology moving forward. PMID:24473594

  15. ISPAE Research Highlights 1995-1997

    NASA Technical Reports Server (NTRS)

    Harwell, Ken

    1997-01-01

    This paper presents ISPAE (Institute for Space Physics, Astrophysics and Education) research highlights from 1995-1997. The topics include: 1) High-Energy Astrophysics (Finding the smoking gun in gamma-ray bursts, Playing peekaboo with gamma ray bursts, and Spectral pulses muddle burst source study, Einstein was right: Black holes do spin, Astronomers find "one-man X-ray band", and Cosmic rays from the supernova next door?); 2) Solar Physics (Bright burst confirms solar storm model, Model predicts speed of solar wind in space, and Angry sunspots snap under the strain); 3) Gravitational Physics; 4) Tether Dynamics; and 5) Space Physics (Plasma winds blow form polar regions, De-SCIFERing thermal electrons, and UVI lets scientists see daytime aurora).

  16. Research highlights: digital assays on chip.

    PubMed

    Kim, Donghyuk; Wei, Qingshan; Kong, Janay Elise; Ozcan, Aydogan; Di Carlo, Dino

    2015-01-01

    The ability to break up a volume of fluid into smaller pieces that are confined or separated to prevent molecular communication/transport is a key capability intrinsic to microfluidic systems. This capability has been used to develop or implement digital versions of traditional molecular analysis assays, including digital PCR and digital immunoassays/ELISA. In these digital versions, the concentration of the target analyte is in a range such that, when sampled into smaller fluid volumes, either a single molecule or no molecule may be present. Subsequent amplification is sensitive enough to obtain a digital readout of the presence of these target molecules. Advantages of such approaches that are claimed include quantification without calibration and robustness to variations in reaction conditions or times because the digital readout is less sensitive to absolute signal intensity levels. Weaknesses of digital approaches include a lower dynamic range of concentrations over which the assay is sensitive, which depends on the total volume that can be analyzed. We highlight recent efforts to expand the dynamic range of digital assays based on exploiting reaction/diffusion phenomena. A side-by-side study that evaluates the strengths of digital assays reveals that the majority of these claims are supported, with specific caveats. Finally, we highlight approaches to apply digital assays to analyze new types of reactions, including the active transport of protons across membranes by ATPases at the single protein level - perhaps opening up new biophysical understanding and screening opportunities, similar to widely deployed single-molecule ion channel analysis. PMID:25410901

  17. Highlights of Commission 37 Science Results

    NASA Astrophysics Data System (ADS)

    Carraro, Giovanni; de Grijs, Richard; Elmegreen, Bruce; Stetson, Peter; Anthony-Twarog, Barbara; Goodwin, Simon; Geisler, Douglas; Minniti, Dante

    2016-04-01

    It is widely accepted that stars do not form in isolation but result from the fragmentation of molecular clouds, which in turn leads to star cluster formation. Over time, clusters dissolve or are destroyed by interactions with molecular clouds or tidal stripping, and their members become part of the general field population. Star clusters are thus among the basic building blocks of galaxies. In turn, star cluster populations, from young associations and open clusters to old globulars, are powerful tracers of the formation, assembly, and evolutionary history of their parent galaxies. Although their importance (e.g., in mapping out the Milky Way) had been recognised for decades, major progress in this area has only become possible in recent years, both for Galactic and extragalactic cluster populations. Star clusters are the observational foundation for stellar astrophysics and evolution, provide essential tracers of galactic structure, and are unique stellar dynamical environments. Star formation, stellar structure, stellar evolution, and stellar nucleosynthesis continue to benefit and improve tremendously from the study of these systems. Additionally, fundamental quantities such as the initial mass function can be successfully derived from modelling either the Hertzsprung-Russell diagrams or the integrated velocity structures of, respectively, resolved and unresolved clusters and cluster populations. Star cluster studies thus span the fields of Galactic and extragalactic astrophysics, while heavily affecting our detailed understanding of the process of star formation in dense environments. This report highlights science results of the last decade in the major fields covered by IAU Commission 37: Star clusters and associations. Instead of focusing on the business meeting - the out-going president presentation can be found here: http://www.sc.eso.org/gcarraro/splinter2015.pdf - this legacy report contains highlights of the most important scientific achievements in

  18. Biotransformation and bioactivation reactions - 2015 literature highlights.

    PubMed

    Baillie, Thomas A; Dalvie, Deepak; Rietjens, Ivonne M C M; Cyrus Khojasteh, S

    2016-05-01

    Since 1972, Drug Metabolism Reviews has been recognized as one of the principal resources for researchers in pharmacological, pharmaceutical and toxicological fields to keep abreast of advances in drug metabolism science in academia and the pharmaceutical industry. With a distinguished list of authors and editors, the journal covers topics ranging from relatively mature fields, such as cytochrome P450 enzymes, to a variety of emerging fields. We hope to continue this tradition with the current compendium of mini-reviews that highlight novel biotransformation processes that were published during the past year. Each review begins with a summary of the article followed by our comments on novel aspects of the research and their biological implications. This collection of highlights is not intended to be exhaustive, but rather to be illustrative of recent research that provides new insights or approaches that advance the field of drug metabolism. Abbreviations NAPQI N-acetyl-p-benzoquinoneimine ALDH aldehyde dehydrogenase AO aldehyde oxidase AKR aldo-keto reductase CES carboxylesterase CSB cystathionine β-synthase CSE cystathionine γ-lyase P450 cytochrome P450 DHPO 2,3-dihydropyridin-4-one ESI electrospray FMO flavin monooxygenase GSH glutathione GSSG glutathione disulfide ICPMS inductively coupled plasma mass spectrometry i.p. intraperitoneal MDR multidrug-resistant NNAL 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol NNK 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone oaTOF orthogonal acceleration time-of-flight PBK physiologically based kinetic PCP pentachlorophenol SDR short-chain dehydrogenase/reductase SULT sulfotransferase TB tuberculosis. PMID:27362326

  19. Active Reading Procedures for Moderating the Effects of Poor Highlighting

    ERIC Educational Resources Information Center

    Gier, Vicki S.; Herring, Daniel; Hudnell, Jason; Montoya, Jodi; Kreiner, David S.

    2010-01-01

    We investigated two active reading techniques intended to eliminate the negative effect on reading comprehension of preexisting, inappropriate highlighting. College students read passages in three highlighting conditions: no highlighting, appropriate highlighting, and inappropriate highlighting. In Experiment 1, 30 students read the passages while…

  20. UKIDSS UDS Progress and Science Highlights

    NASA Astrophysics Data System (ADS)

    Hartley, W. G.; Almaini, O.; Foucaud, S.

    In this contribution we provide a comprehensive update of the progress of the UDS survey and the science that has already been achieved through its use. In the context of this meeting (a look-back over the life of UKIRT to date) we begin with a retrospective of the original motivation for the UDS and how it remains well-placed to answer some of the biggest questions in extra-galactic astronomy. Following this is a progress report of the UDS data collection and a summary of the multi-wavelength data covering the field. We then detail a few of the science highlights that have resulted from the survey, concentrating on those which rely most heavily on the infrared data and are of greatest impact. With the survey now less than 3 years from completion, we end with a look forward to the final probable depths and the continuing data acquisition which will maintain the UDS as one of the most important surveys for several years to come.

  1. STS-96 Mission Highlights. Part 1

    NASA Technical Reports Server (NTRS)

    1999-01-01

    In this first part of a three-part video mission-highlights set, the flight of the STS-96 Space Shuttle Orbiter Discovery is reviewed. The flight crew consists of Kent V. Rominger, Commander; Rick D. Husband, Pilot; and Mission Specialists Ellen Ochoa, Tamara E. Jernigan, Daniel T. Barry, Julie Payette (Canadian), and Valery Ivanovich Tokarev (Russian). The primary goals of this mission were to work on logistics and resupply the International Space Station (ISS). This is the first flight to dock to the International Space Station. The primary payloads are the Russian cargo crane, known as STRELA, which the astronauts mount to the exterior of the Russian station segment, the SPACEHAB Oceaneering Space System Box (SHOSS), and a U.S. built crane called the ORU Transfer Device (OTD). Other payloads include the Student Tracked Atmospheric Research Satellite for Heuristic International Networking Equipment (STARSHINE), the Shuttle Vibration Forces Experiment (SVF), and the Orbiter Integrated Vehicle Health Monitoring - HEDS Technology Demonstration (IVHM HTD). The traditional pre-launch breakfast, being suited up, entry into the Shuttle, and views of the liftoff from several different vantage points are shown. In-flight footage includes views from the robot arm conducting a television survey of Discovery's payload bay and the flawless docking of the Unity module with the International Space Station. During the docking, camera views from both the ISS and Discovery are presented. These activities make up the first three Flight Days of STS-96.

  2. Recent highlights from ISOLDE@CERN

    NASA Astrophysics Data System (ADS)

    Fraile, L. M.

    2005-09-01

    The ISOLDE online mass separator located at CERN provides a large variety of radioactive ion beams for research on nuclear physics, nuclear astrophysics, fundamental interactions, atomic physics, radiochemistry, nuclear medicine, condensed matter science, life sciences and others. The recently operational REX-ISOLDE post-accelerator is capable of accelerating the isotopes produced at ISOLDE to energies of up to 3.0MeV/u by using an ion trap and charge breeder and a compact linear accelerator structure. The post-accelerator is complemented by a highly segmented Ge array in conjunction with a compact silicon strip detector at one of the secondary target positions, while a general spectroscopy setup occupies a second station. REX-ISOLDE has opened up the possibility of nuclear spectroscopy studies by means of transfer reactions and Coulomb excitation of exotic nuclei. The facility maintains an extensive physics-driven target and ion source development program, which has helped ISOLDE keep its international status for more than 35 years. Some recent experimental highlights and technical developments are discussed.

  3. STS-114 Flight Day 3 Highlights

    NASA Technical Reports Server (NTRS)

    2005-01-01

    Video coverage of Day 3 includes highlights of STS-114 during the approach and docking of Discovery with the International Space Station (ISS). The Return to Flight continues with space shuttle crew members (Commander Eileen Collins, Pilot James Kelly, Mission Specialists Soichi Noguchi, Stephen Robinson, Andrew Thomas, Wendy Lawrence, and Charles Camarda) seen in onboard activities on the fore and aft portions of the flight deck during the orbiter's approach. Camarda sends a greeting to his family, and Collins maneuvers Discovery as the ISS appears steadily closer in sequential still video from the centerline camera of the Orbiter Docking System. The approach includes video of Discovery from the ISS during the orbiter's Rendezvous Pitch Maneuver, giving the ISS a clear view of the thermal protection systems underneath the orbiter. Discovery docks with the Destiny Laboratory of the ISS, and the shuttle crew greets the Expedition 11 crew (Commander Sergei Krikalev and NASA ISS Science Officer and Flight Engineer John Phillips) of the ISS onboard the station. Finally, the Space Station Remote Manipulator System hands the Orbiter Boom Sensor System to its counterpart, the Shuttle Remote Manipulator System.

  4. STS-107 Crew Choice Television Highlights

    NASA Astrophysics Data System (ADS)

    2003-01-01

    The STS-107 flight day highlights begin with a shot inside the flight deck of the Space Shuttle Columbia where Commander Rick Husband, Pilot William McCool, and Mission Specialists David Brown and Kalpana Chawla are seated. The actual liftoff of the Space Shuttle Columbia is shown with Mission Specialists Michael Anderson and Laurel Clark, and Payload Specialist Ilan Ramon seated on the middeck of the spacecraft. Mission Specialist David Brown exits his seat to take pictures of the external tank while Michael Anderson also prepares to take photographs. A beautiful shot of the orbiter flying over Egypt is presented. A view of the Spacehab Research Double Module is shown where crystals are growing in microgravity. Laurel Clark is also shown working on the Bioreactor experiment. Michael Anderson is shown performing various breathing experiments in space. This video shows the last flight of STS-107 during ascent as the crew is seated in the flight deck and middeck of the Space Shuttle Columbia.

  5. WFC3: In-Flight Performance Highlights

    NASA Technical Reports Server (NTRS)

    Kimble, Randy A.

    2010-01-01

    Wide Field Camera 3 (WFC3), a powerful new imager for the Hubble Space Telescope (HST), was successfully installed in the telescope in May 2009 during the first dramatic spacewalk of space shuttle flight STS-125, also known as HST Servicing Mission 4. This new camera offers unique observing capabilities in two channels spanning a broad wavelength range from the near ultraviolet to the near infrared (200-1000nm in the UV/Visible [UVIS] channel; 850-1700nm in the IR channel). After an initial outgassing period, WFC3 was cooled to its observing configuration in June. In the following months, a highly successful Servicing Mission Observatory Verification (SMOV4) program was executed, which has confirmed the exciting scientific potential of the instrument. Detailed performance results from the SMOV 4 program are presented in a number of papers in this session. In this paper, we highlight some top-level performance assessments (throughput, limiting magnitudes, survey speeds) for WFC3, which is now actively engaged in the execution of forefront astronomical observing programs.

  6. STS-114 Flight Day 9 Highlights

    NASA Technical Reports Server (NTRS)

    2005-01-01

    The highlight of Day 9 is the third extravehicular activity (EVA) of the STS-114 mission (Commander Eileen Collins, Pilot James Kelly, Mission Specialists Soichi Noguchi, Stephen Robinson, Andrew Thomas, Wendy Lawrence, and Charles Camarda). Astronauts Noguchi and Robinson are seen preparing for the EVA in the closed payload bay of Space Shuttle Discovery; on the EVA they install on the International Space Station (ISS) a Materials on the International Space Station Experiments (MISSE) unit, an External Stowage Platform (ESP-2), and a wireless antenna. The astronauts are seen working on the ISS under different lighting conditions, and use a pistol-grip tool to remove ESP-2 from the shuttle payload bay. The Space Station Remote Manipulator System then carries Robinson to the underside of the Discovery orbiter, where he communicates with Mission Control during the delicate and unprecedented removal of gap fillers from between the shuttle's tiles. Before and the after the EVA the video includes views of a damaged thermal blanket beneath the shuttle cockpit window. Other views of the shuttle include pans along the underside and topside by the Orbiter Boom Sensor System. The video also includes a view from orbit of Kazakhstan.

  7. Laboratory for Atmospheres 2008 Technical Highlights

    NASA Technical Reports Server (NTRS)

    Cote, Charles E.

    2009-01-01

    The 2008 Technical Highlights describes the efforts of all members of the Laboratory for Atmospheres. Their dedication to advancing Earth Science through conducting research, developing and running models, designing instruments, managing projects, running field campaigns, and numerous other activities, is highlighted in this report. The Laboratory for Atmospheres (Code 613) is part of the Earth Sciences Division (Code 610), formerly the Earth Sun Exploration Division, under the Sciences and Exploration Directorate (Code 600) based at NASA s Goddard Space Flight Center in Greenbelt, Maryland. In line with NASA s Exploration Initiative, the Laboratory executes a comprehensive research and technology development program dedicated to advancing knowledge and understanding of the atmospheres of Earth and other planets. The research program is aimed at understanding the influence of solar variability on the Earth s climate; predicting the weather and climate of Earth; understanding the structure, dynamics, and radiative properties of precipitation, clouds, and aerosols; understanding atmospheric chemistry, especially the role of natural and anthropogenic trace species on the ozone balance in the stratosphere and the troposphere; and advancing our understanding of physical properties of Earth s atmosphere. The research program identifies problems and requirements for atmospheric observations via satellite missions. Laboratory scientists conceive, design, develop, and implement ultraviolet, infrared, optical, radar, laser, and lidar technology for remote sensing of the atmosphere. Laboratory members conduct field measurements for satellite data calibration and validation, and carry out numerous modeling activities. These modeling activities include climate model simulations, modeling the chemistry and transport of trace species on regional-to-global scales, cloud-resolving models, and development of next-generation Earth system models. Interdisciplinary research is carried

  8. "Suzaku Highlight Results on Supernova Remnants"

    NASA Technical Reports Server (NTRS)

    Petre, Robert

    2006-01-01

    Highlights of the early Suzaku (formerly Astro-E2) observations of supernova remnants are presented. Suzaku offers unique capabilities for the study of supernova remnants. The unprecedented combination of imaging and spectral resolution below 1 keV in the X-ray Imaging Spectrometer (XIS) makes possible mapping of C, N and O abundances in Galactic remnants of all ages. The first detection of carbon lines in the Cygnus Loop and mapping of the O VII to O VIII ratio in SN 1006 demonstrate this capability. The XIS sensitivity to soft, low surface brightness emission is exemplified by spectroscopy in the 0.3-1.0 keV band of the North Polar Spur and other Galactic ISM structures. Such observations make possible inferences about plasma conditions and abundances. The sensitivity above 6 keV via a combination of the XIS (below 10 keV) and the Hard X-ray Detector (above 10 keV) allows broad band (2-40 keV) spectroscopy and mapping of extended remnants with hard emission components. These components are generally associated with sites of particle acceleration, and measuring their spectral shape potentially provides information about the TeV electron population and its acceleration and energy loss mechanisms. Examples of such remnants observed by Suzaku are the non-thermal emission dominated remnants RX J1713.7-3946 and RX J0852.0-4622, for which flux beyond 30 keV has been detected. The status of the mission and prospects for future groundbreaking observations of supernova remnants will be discussed.

  9. Cluster recent highlights in magnetospheric physics

    NASA Astrophysics Data System (ADS)

    Escoubet, C. Philippe; Laakso, Harri; Goldstein, Mevlyn; Masson, Arnaud

    2016-07-01

    After more than 15 years in space, the Cluster mission is continuing to deliver groundbreaking results, thanks to its ability to move the four spacecraft with respect to each other, according to the science topic to be studied. The main goal of the Cluster mission, made of four identical spacecraft carrying each 11 complementary instruments, is to study in three dimensions the key plasma processes at work in the main regions of the Earth's environment: solar wind and bow shock, magnetopause, polar cusps, magnetotail, and auroral zone. During the course of the mission, the relative distance between the four spacecraft has been varied more than 55 times from a few km up to 36000 km to address the various scientific objectives. The smallest distance achieved between two Cluster spacecraft was 3.1 km in December 2015, about 50 times smaller than planned at the beginning of the mission. The rate of change of separation distances has accelerated in the last few years with the Guest Investigator programme that allowed scientists in the community to propose special science programmes requiring a new spacecraft constellation. We will present recent science highlights obtained such as solar wind reconnection and bifurcated current sheet development, multi-altitude measurements of field aligned currents, reconnection efficiency in accelerating particles and effect of cold ions, motion of X-lines, speed and direction of tail reconnection events, flux transfer events evolution, new method to find magnetic nulls outside the Cluster tetrahedron, interplanetary shock waves very quick damping and origin of theta auroras. We will also present the distribution of data through the Cluster Science Data System (CSDS), and the Cluster Science Archive (CSA). CSA was implemented to provide, for the first time for a plasma physics mission, a permanent and public archive of all the high-resolution data from all instruments.

  10. The 1990 annual statistics and highlights report

    NASA Technical Reports Server (NTRS)

    Green, James L.

    1991-01-01

    The National Space Science Data Center (NSSDC) has archived over 6 terabytes of space and Earth science data accumulated over nearly 25 years. It now expects these holdings to nearly double every two years. The science user community needs rapid access to this archival data and information about data. The NSSDC has been set on course to provide just that. Five years ago the NSSDC came on line, becoming easily reachable for thousands of scientists around the world through electronic networks it managed and other international electronic networks to which it connected. Since that time, the data center has developed and implemented over 15 interactive systems, operational nearly 24 hours per day, and is reachable through DECnet, TCP/IP, X25, and BITnet communication protocols. The NSSDC is a clearinghouse for the science user to find data needed through the Master Directory system whether it is at the NSSDC or deposited in over 50 other archives and data management facilities around the world. Over 13,000 users accessed the NSSDC electronic systems, during the past year. Thousands of requests for data have been satisfied, resulting in the NSSDC's sending out a volume of data last year that nearly exceeded a quarter of its holdings. This document reports on some of the highlights and distribution statistics for most of the basic NSSDC operational services for fiscal year 1990. It is intended to be the first of a series of annual reports on how well NSSDC is doing in supporting the space and Earth science user communities.