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Sample records for protein sp-b strongly

  1. A Function of Lung Surfactant Protein SP-B

    NASA Astrophysics Data System (ADS)

    Longo, M. L.; Bisagno, A. M.; Zasadzinski, J. A. N.; Bruni, R.; Waring, A. J.

    1993-07-01

    The primary function of lung surfactant is to form monolayers at the alveolar interface capable of lowering the normal surface tension to near zero. To accomplish this process, the surfactant must be capable of maintaining a coherent, tightly packed monolayer that avoids collapse during expiration. The positively charged amino-terminal peptide SP-B1-25 of lung surfactant-specific protein SP-B increases the collapse pressure of an important component of lung surfactant, palmitic acid (PA), to nearly 70 millinewtons per meter. This alteration of the PA isotherms removes the driving force for "squeeze-out" of the fatty acids from the primarily dipalmitoylphosphatidylcholine monolayers of lung surfactant. An uncharged mutant of SP-B1-25 induced little change in the isotherms, suggesting that a specific charge interaction between the cationic peptide and the anionic lipid is responsible for the stabilization. The effect of SP-B1-25 on fatty acid isotherms is remarkably similar to that of simple poly-cations, suggesting that such polymers might be useful as components of replacement surfactants for the treatment of respiratory distress syndrome.

  2. The Interactions between SP-B Protein and Anionic Lipids Found in Human Lung Surfactant

    NASA Astrophysics Data System (ADS)

    Lee, Ka Yee C.; Lipp, Michael M.; Zasadzinski, Joseph A.; Waring, Alan J.

    1997-03-01

    Several lung pathologies, including neonatal respiratory distress syndrome, are characterized by a failure of the lung surfactant (LS) system to function properly. Utilizing fluorescence and Brewster angle microscopy, we have investigated the phase behavior of monolayers of binary mixtures of anionic lipids found in LS (palmitic acid, and both saturated and unsaturated phosphatidylglycerol) with both the full length SP-B protein and a shorter, 25-amino acid sequence based on its amino terminus. We found that both protein candidates interact specifically yet differently with each of the lipid components, altering their phase behavior to resemble more closely to that of an ideal LS monolayer. The SP-B protein incorporates itself in the lipid monolayer in all cases, and partitions preferentially into the fluid-type phases during phase transitions; its presence drastically changes the collapse mechanism of the monolayer.

  3. Dimeric N-terminal segment of human surfactant protein B (dSP-B(1-25)) has enhanced surface properties compared to monomeric SP-B(1-25).

    PubMed Central

    Veldhuizen, E J; Waring, A J; Walther, F J; Batenburg, J J; van Golde, L M; Haagsman, H P

    2000-01-01

    Surfactant protein B (SP-B) is a 17-kDa dimeric protein produced by alveolar type II cells. Its main function is to lower the surface tension by inserting lipids into the air/liquid interface of the lung. SP-B's function can be mimicked by a 25-amino acid peptide, SP-B(1-25), which is based on the N-terminal sequence of SP-B. We synthesized a dimeric version of this peptide, dSP-B(1-25), and the two peptides were tested for their surface activity. Both SP-B(1-25) and dSP-B(1-25) showed good lipid mixing and adsorption activities. The dimeric peptide showed activity comparable to that of native SP-B in the pressure-driven captive bubble surfactometer. Spread surface films led to stable near-zero minimum surface tensions during cycling while protein free, and films containing SP-B(1-25) lost material from the interface during compression. We propose that dimerization of the peptide is required to create a lipid reservoir attached to the monolayer from which new material can enter the surface film upon expansion of the air/liquid interface. The dimeric state of SP-B can fulfill the same function in vivo. PMID:10866963

  4. Effects of lung surfactant proteins, SP-B and SP-C, and palmitic acid on monolayer stability.

    PubMed Central

    Ding, J; Takamoto, D Y; von Nahmen, A; Lipp, M M; Lee, K Y; Waring, A J; Zasadzinski, J A

    2001-01-01

    Langmuir isotherms and fluorescence and atomic force microscopy images of synthetic model lung surfactants were used to determine the influence of palmitic acid and synthetic peptides based on the surfactant-specific proteins SP-B and SP-C on the morphology and function of surfactant monolayers. Lung surfactant-specific protein SP-C and peptides based on SP-C eliminate the loss to the subphase of unsaturated lipids necessary for good adsorption and respreading by inducing a transition between monolayers and multilayers within the fluid phase domains of the monolayer. The morphology and thickness of the multilayer phase depends on the lipid composition of the monolayer and the concentration of SP-C or SP-C peptide. Lung surfactant protein SP-B and peptides based on SP-B induce a reversible folding transition at monolayer collapse that allows all components of surfactant to be retained at the interface during respreading. Supplementing Survanta, a clinically used replacement lung surfactant, with a peptide based on the first 25 amino acids of SP-B also induces a similar folding transition at monolayer collapse. Palmitic acid makes the monolayer rigid at low surface tension and fluid at high surface tension and modifies SP-C function. Identifying the function of lung surfactant proteins and lipids is essential to the rational design of replacement surfactants for treatment of respiratory distress syndrome. PMID:11325728

  5. Combinations of fluorescently labeled pulmonary surfactant proteins SP-B and SP-C in phospholipid films.

    PubMed Central

    Nag, K; Taneva, S G; Perez-Gil, J; Cruz, A; Keough, K M

    1997-01-01

    Hydrophobic pulmonary surfactant (PS) proteins B (SP-B) and C (SP-C) modulate the surface properties of PS lipids. Epifluorescence microscopy was performed on solvent-spread monolayers of fluorescently labeled porcine SP-B (R-SP-B, labeled with Texas Red) and SP-C (F-SP-C, labeled with fluorescein) in dipalmitoylphosphatidylcholine (DPPC) (at protein concentrations of 10 and 20 wt%, and 10 wt% of both) under conditions of cyclic compression and expansion. Matrix-assisted laser desorption/ionization (MALDI) spectroscopy of R-SP-B and F-SP-C indicated that the proteins were intact and labeled with the appropriate fluorescent probe. The monolayers were compressed and expanded for four cycles at an initial rate of 0.64 A2 x mol(-1) x s(-1) (333 mm2 x s x [-1]) up to a surface pressure pi approximately 65 mN/m, and pi-area per residue (pi-A) isotherms at 22 +/- 1 degrees C were obtained. The monolayers were microscopically observed for the fluorescence emission of the individual proteins present in the film lipid matrix, and their visual features were video recorded for image analysis. The pi-A isotherms of the DPPC/protein monolayers showed characteristic "squeeze out" effects at pi approximately 43 mN/m for R-SP-B and 55 mN/m for F-SP-C, as had previously been observed for monolayers of the native proteins in DPPC. Both proteins associated with the expanded (fluid) phase of DPPC monolayers remained in or associated with the monolayers at high pi (approximately 65 mN/m) and redispersed in the monolayer upon its reexpansion. At comparable pi and area/molecule of the lipid, the proteins reduced the amounts of condensed (gel-like) phase of DPPC monolayers, with F-SP-C having a greater effect on a weight basis than did R-SP-B. In any one of the lipid/protein monolayers the amounts of the DPPC in condensed phase were the same at equivalent pi during compression and expansion and from cycle to cycle. This indicated that only minor loss of components from these systems

  6. Conformational Stability of the NH2-Terminal Propeptide of the Precursor of Pulmonary Surfactant Protein SP-B.

    PubMed

    Bañares-Hidalgo, Ángeles; Pérez-Gil, Jesús; Estrada, Pilar

    2016-01-01

    Assembly of pulmonary surfactant lipid-protein complexes depends on conformational changes coupled with proteolytic maturation of proSP-B, the precursor of pulmonary surfactant protein B (SP-B), along the surfactant biogenesis pathway in pneumocytes. Conformational destabilization of the N-terminal propeptide of proSP-B (SP-BN) triggers exposure of the mature SP-B domain for insertion into surfactant lipids. We have studied the conformational stability during GdmCl- or urea-promoted unfolding of SP-BN with trp fluorescence and circular dichroism spectroscopies. Binding of the intermediate states to bis-ANS suggests their molten globule-like character. ΔG0H2O was ~ 12.7 kJ·mol-1 either with urea or GdmCl. None of the thermal transitions of SP-BN detected by CD correspond to protein unfolding. Differential scanning calorimetry of SP-BN evidenced two endothermic peaks involved in oligomer dissociation as confirmed with 2 M urea. Ionic strength was relevant since at 150 mM NaCl, the process originating the endotherm at the highest temperature was irreversible (Tm2 = 108.5°C) with an activation energy of 703.8 kJ·mol-1. At 500 mM NaCl the process became reversible (Tm2 = 114.4°C) and data were fitted to the Non-two States model with two subpeaks. No free thiols in the propeptide could be titrated by DTNB with or without 5.7 M GdmCl, indicating disulfide bonds establishment.

  7. Conformational Stability of the NH2-Terminal Propeptide of the Precursor of Pulmonary Surfactant Protein SP-B

    PubMed Central

    Bañares-Hidalgo, Ángeles; Estrada, Pilar

    2016-01-01

    Assembly of pulmonary surfactant lipid-protein complexes depends on conformational changes coupled with proteolytic maturation of proSP-B, the precursor of pulmonary surfactant protein B (SP-B), along the surfactant biogenesis pathway in pneumocytes. Conformational destabilization of the N-terminal propeptide of proSP-B (SP-BN) triggers exposure of the mature SP-B domain for insertion into surfactant lipids. We have studied the conformational stability during GdmCl- or urea-promoted unfolding of SP-BN with trp fluorescence and circular dichroism spectroscopies. Binding of the intermediate states to bis-ANS suggests their molten globule-like character. ΔG0H2O was ~ 12.7 kJ·mol-1 either with urea or GdmCl. None of the thermal transitions of SP-BN detected by CD correspond to protein unfolding. Differential scanning calorimetry of SP-BN evidenced two endothermic peaks involved in oligomer dissociation as confirmed with 2 M urea. Ionic strength was relevant since at 150 mM NaCl, the process originating the endotherm at the highest temperature was irreversible (Tm2 = 108.5°C) with an activation energy of 703.8 kJ·mol-1. At 500 mM NaCl the process became reversible (Tm2 = 114.4°C) and data were fitted to the Non-two States model with two subpeaks. No free thiols in the propeptide could be titrated by DTNB with or without 5.7 M GdmCl, indicating disulfide bonds establishment. PMID:27380171

  8. Experimental Study on How Human Lung Surfactant Protein SP-B1-25 is Oxidized by Ozone in the Presence of Fe(II) and Ascorbic Acid

    NASA Astrophysics Data System (ADS)

    Colussi, A. J.; Enami, S.; Hoffmann, M. R.

    2014-12-01

    We will report the results of experiments on the chemical fate of the human lung surfactant protein SP-B1-25 upon exposure to gaseous ozone in realistic aqueous media simulating the conditions prevalent in epithelial lining fluids in polluted ambient air. Our experiments consist of exposing aqueous microjets containing SP-B1-25, the natural antioxidant ascorbic acid, and the Fe2+ carried by most atmospheric fine particulates, under mild acidic conditions, such as those created by the innate lung host defense response. Reactants and the products of such interactions are detected via online electrospray ionization mass spectrometry. We will show that ascorbic acid largely inhibits the ozonation of SP-B1-25 in the absence of Fe2+, leading to the formation of an ascorbic acid ozonide (Enami et al., PNAS 2008). In the presence of Fe2+, however, the ozonide decomposes into reactive intermediates that result in the partial oxidation of SP-B1-25, presumable affecting its function as surfactant. We infer that these experimental results establish a plausible causal link for the observed synergic adverse health effects of ambient ozone and fine particulates

  9. Aberrant processing forms of lung surfactant proteins SP-B and SP-C revealed by high-resolution mass spectrometry.

    PubMed

    Galetskiy, Dmitry; Woischnik, Markus; Ripper, Jan; Griese, Matthias; Przybylski, Michael

    2008-01-01

    The mutation (g.1286T>C) of the pulmonary surfactant-associated protein C gene (SFTPC) leads to the I73T substitution in the precursor protein (pro-SP-C) and results in interstitial lung disease with the histological pattern of non-specific interstitial pneumonia and pulmonary alveolar proteinosis. Central for the disease is the abnormal processing of the SP-C pro-protein to mature SP-C; however little is known about the nature of intermediates and processing products. We report here the application of high resolution Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry to the characterization of processing intermediates of hydrophobic pulmonary surfactant proteins SP-B and SP-C in intra- alveolar surfactant material of a patient with I73T mutation. SP-C and SP-B processing forms were separated from broncho-alveolar lavage fluid using chloroform/methanol extraction and sodium dodecyl sulfate poly acrylamide gel electrophoreis, detected by Western blot and identified by electrospray- and matrix-assisted laser desorption/ionization-FT-ICR mass spectrometry. The mass spectrometric and immuno-analytical results show the intra-alveolar accumulation of an aberrant C-terminal SP-C processing products in which the mature SP-C protein part is missing and aberrant processing intermediates of SP-B.

  10. Lipid Polymorphism Induced by Surfactant Peptide SP-B1-25

    PubMed Central

    Farver, R. Suzanne; Mills, Frank D.; Antharam, Vijay C.; Chebukati, Janetricks N.; Fanucci, Gail E.; Long, Joanna R.

    2010-01-01

    Pulmonary surfactant protein B (SP-B) is an essential protein for lowering surface tension in the alveoli. SP-B1-25, a peptide comprised of the N-terminal 25 amino-acid residues of SP-B, is known to retain much of the biological activity of SP-B. Circular dichroism has shown that when SP-B1-25 interacts with negatively charged lipid vesicles, it contains significant helical structure for the lipid compositions and peptide/lipid ratios studied here. The effect of SP-B1-25 on lipid organization and polymorphisms was investigated via DSC, dynamic light scattering, transmission electron microscopy, and solid-state NMR spectroscopy. At 1-3 mol% peptide and physiologic temperature, SP-B1-25 partitions at the interface of negatively charged PC/PG lipid bilayers. In lipid mixtures containing 1-5 mol% peptide, the structure of SP-B1-25 remains constant, but 2H and 31P NMR spectra show the presence of an isotropic lipid phase in exchange with the lamellar phase below the Tm of the lipids. This behavior is observed for both DPPC/POPG and POPC/POPG lipid mixtures as well as for both the PC and PG components of the mixtures. For 1-3 mol% SP-B1-25, a return to a single lamellar phase above the lipid mixture Tm is observed, but for 5 mol% SP-B1-25 a significant isotropic component is observed at physiologic temperatures for DPPC and exchange broadening is observed in 2H and 31P NMR spectra of the other lipid components in the two mixtures. DLS and TEM rule out the formation of micellar structures and suggest that SP-B1-25 promotes the formation of a fluid isotropic phase. The ability of SP-B1-25 to fuse lipid lamellae via this mechanism, particularly those enriched in DPPC, suggests a specific role for the highly conserved N-terminus of SP-B in the packing of lipid lamellae into surfactant lamellar bodies or in stabilizing multilayer structures at the air-liquid interface. Importantly, this behavior has not been seen for the other SP-B fragments of SP-B8-25 and SP-B59

  11. Amplification of steroid-mediated SP-B expression by physiological levels of caffeine.

    PubMed

    Fehrholz, Markus; Hütten, Matthias; Kramer, Boris W; Speer, Christian P; Kunzmann, Steffen

    2014-01-01

    Factors positively influencing surfactant homeostasis in general and surfactant protein B (SP-B) expression in particular are considered of clinical importance regarding an improvement of lung function in preterm infants. The objective of this study was to identify effects of physiological levels of caffeine on glucocorticoid-mediated SP-B expression in vitro and in vivo. Levels of SP-B and pepsinogen C were quantified by quantitative real-time RT-PCR or immunoblotting in NCI-H441 cells daily exposed to caffeine and/or dexamethasone (DEX). In vivo, SP-B expression was analyzed in bronchoalveolar lavage (BAL) of preterm sheep exposed to antenatal DEX and/or postnatal caffeine. If DEX and caffeine were continuously present, SP-B mRNA and protein levels were increased for up to 6 days after induction (P < 0.05). Additionally, caffeine enhanced SP-B mRNA expression in DEX-pretreated cells (P < 0.05). Moreover, caffeine amplified DEX-induced pepsinogen C mRNA expression (P < 0.05). After short-term treatment with caffeine in vivo, only slightly higher SP-B levels could be detected in BAL of preterm sheep following antenatal DEX, combined with an increase of arterial oxygen partial pressure (P < 0.01). Our data demonstrated that the continuous presence of caffeine in vitro is able to amplify DEX-mediated SP-B expression. In contrast, short-term improvement of lung function in vivo is likely to be independent of altered SP-B transcription and translation. An impact of caffeine on release of surfactant reservoirs from lamellar bodies could, however, quickly affect SP-B content in BAL, which has to be further investigated. Our findings indicate that caffeine is able to amplify main effects of glucocorticoids that result from changes in surfactant production, maturation, and release.

  12. Genetic Polymorphisms of SP-A, SP-B, and SP-D and Risk of Respiratory Distress Syndrome in Preterm Neonates

    PubMed Central

    Chang, Hong-Yu; Li, Fang; Li, Feng-Sheng; Zheng, Cheng-Zhong; Lei, Yan-Zhe; Wang, Jing

    2016-01-01

    Background We examined selected polymorphisms in 3 pulmonary surfactant-associated proteins (SP) for their influence on serum SP levels and risk of respiratory distress syndrome (RDS) in preterm neonates. Material/Methods Premature infants from a Han population were enrolled, including 100 premature infants with RDS (case group) and 120 premature infants without RDS (control group). SNP genotyping for SP-A (+186A/G and +655C/T), SP-B (−18A/C and 1580C/T), and SP-D (Met11ThrT/C and Ala160ThrG/A) used polymerase chain reaction-restriction fragment length polymorphism. Haplotypes were calculated with Shesis software and serum SP-A/B/D levels were quantified by ELISA. Results Case and control groups exhibited significant differences in genotype and allele frequencies of SP-A (+186A/G, +655C/T) and SP-B (1580C/T). However, no statistically significant differences were observed in the allele and genotype frequencies of SP-B −18A/C, SP-D Met11ThrT/C, and SP-D Ala160ThrG/A. Importantly, serum SP-A and SP-B levels were reduced in RDS patients carrying SP-A (+186A/G, +655C/T) and SP-B (1580C/T) polymorphisms. AA genotype of +186A/G, SP-A level, and CC genotype of 1580C/T were independently correlated with increased RDS risk. Conclusions SP-A (+186A/G) and SP-B (1580C/T) polymorphisms are strongly associated with the risk of RDS in preterm infants. Notably, reduced serum SP-A levels were correlated with a high risk of RDS and may serve as novel biomarkers for RDS detection and monitoring. PMID:28011976

  13. Quantum Strong Coupling with Protein Vibrational Modes.

    PubMed

    Vergauwe, Robrecht M A; George, Jino; Chervy, Thibault; Hutchison, James A; Shalabney, Atef; Torbeev, Vladimir Y; Ebbesen, Thomas W

    2016-10-07

    In quantum electrodynamics, matter can be hybridized to confined optical fields by a process known as light-matter strong coupling. This gives rise to new hybrid light-matter states and energy levels in the coupled material, leading to modified physical and chemical properties. Here, we report for the first time the strong coupling of vibrational modes of proteins with the vacuum field of a Fabry-Perot mid-infrared cavity. For two model systems, poly(l-glutamic acid) and bovine serum albumin, strong coupling is confirmed by the anticrossing in the dispersion curve, the square root dependence on the concentration, and a vacuum Rabi splitting that is larger than the cavity and vibration line widths. These results demonstrate that strong coupling can be applied to the study of proteins with many possible applications including the elucidation of the role of vibrational dynamics in enzyme catalysis and in H/D exchange experiments.

  14. DIFFERENTIAL SUSCEPTIBILITY OF HUMAN SP-B GENETIC VARIANTS ON LUNG INJURY CAUSED BY BACTERIAL PNEUMONIA AND THE EFFECT OF A CHEMICALLY MODIFIED CURCUMIN.

    PubMed

    Xu, Yongan; Ge, Lin; Abdel-Razek, Osama; Jain, Sumeet; Liu, Zhiyong; Hong, Yucai; Nieman, Gary; Johnson, Francis; Golub, Lorne M; Cooney, Robert N; Wang, Guirong

    2016-04-01

    Staphylococcus aureus is a common cause of nosocomial pneumonia frequently resulting in acute respiratory distress syndrome (ARDS). Surfactant protein B (SP-B) gene expresses two proteins involved in lowering surface tension and host defense. Genotyping studies demonstrate a significant association between human SP-B genetic variants and ARDS. Curcumins have been shown to attenuate host inflammation in many sepsis models. Our hypothesis is that functional differences of SP-B variants and treatment with curcumin (CMC2.24) modulate lung injury in bacterial pneumonia. Humanized transgenic mice, expressing either SP-B T or C allele without mouse SP-B gene, were used. Bioluminescent labeled S. aureus Xen 36 (50 μL) was injected intratracheally to cause pneumonia. Infected mice received daily CMC2.24 (40 mg/kg) or vehicle alone by oral gavage. Dynamic changes of bacteria were monitored using in vivo imaging system. Histological, cellular, and molecular indices of lung injury were studied in infected mice 48 h after infection. In vivo imaging analysis revealed total flux (bacterial number) was higher in the lung of infected SP-B-C mice compared with infected SP-B-T mice (P < 0.05). Infected SP-B-C mice demonstrated increased mortality, lung injury, apoptosis, and NF-κB expression compared with infected SP-B-T mice. Compared with controls, CMC2.24 treatment significantly reduced the following: mortality, total bacterial flux and lung tissue apoptosis, inflammatory cells, NF-κB expression (P < 0.05), and MMPs-2, -9, -12 activities (P < 0.05). We conclude that mice with SP-B-C allele are more susceptible to S. aureus pneumonia than mice with SP-B-T allele, and that CMC2.24 attenuates lung injury thus reducing mortality.

  15. Phenanthrene degradation by Biejerinickia sp. B8/36

    SciTech Connect

    Strandberg, G.W.; Abraham, T.J. Jr.; Frazier, G.C.

    1986-01-01

    The use of fossil fuels has greatly increased the ubiquity of polynuclear aromatic hydrocarbons (PAHs) in the environment, and their potential toxicity has generated considerable interest in the ability of microorganisms to utilize and/or detoxify these pollutants. One PAH of concern is phenanthrene. Numerous microbial species are known to degrade phenanthrene and there appear to be several metabolic routes available, depending upon the species, strain, and even the cultural conditions. Although there is a substantial amount of literature on the metabolic pathways of phenanthrene utilization, the authors have found little information regarding the effects of environmental conditions on phenanthrene degradation rates. Such information would be of importance to understanding the fate of this compound in natural and controlled (i.e., wastewater treatment) biological systems. During preliminary experiments, the authors found Beijerinickia sp. B3/36 to be unable to grow solely on phenanthrene, but capable of growth and phenanthrene utilization when yeast extract was supplied. The authors discuss the effects of pH and temperature on growth and phenanthrene degradation by intact cells of Biejerinickia sp. B8/36.

  16. Spectroscopic Evidences for Strong Hydrogen Bonds with Selenomethionine in Proteins.

    PubMed

    Mundlapati, V Rao; Sahoo, Dipak Kumar; Ghosh, Sanat; Purame, Umesh Kumar; Pandey, Shubhant; Acharya, Rudresh; Pal, Nitish; Tiwari, Prince; Biswal, Himansu S

    2017-02-16

    Careful protein structure analysis unravels many unknown and unappreciated noncovalent interactions that control protein structure; one such unrecognized interaction in protein is selenium centered hydrogen bonds (SeCHBs). We report, for the first time, SeCHBs involving the amide proton and selenium of selenomethionine (Mse), i.e., amide-N-H···Se H-bonds discerned in proteins. Using mass selective and conformer specific high resolution vibrational spectroscopy, gold standard quantum chemical calculations at CCSD(T), and in-depth protein structure analysis, we establish that amide-N-H···Se and amide-N-H···Te H-bonds are as strong as conventional amide-NH···O and amide-NH···O═C H-bonds despite smaller electronegativity of selenium and tellurium than oxygen. It is in fact, electronegativity, atomic charge, and polarizability of the H-bond acceptor atoms are at play in deciding the strength of H-bonds. The amide-N-H···Se and amide-N-H···Te H-bonds presented here are not only new additions to the ever expanding world of noncovalent interactions, but also are of central importance to design new force-fields for better biomolecular structure simulations.

  17. Reaction mechanism of fluoroacetate dehalogenase from Moraxella sp. B.

    PubMed

    Liu, J Q; Kurihara, T; Ichiyama, S; Miyagi, M; Tsunasawa, S; Kawasaki, H; Soda, K; Esaki, N

    1998-11-20

    Fluoroacetate dehalogenase (EC 3.8.1.3) catalyzes the dehalogenation of fluoroacetate and other haloacetates. The amino acid sequence of fluoroacetate dehalogenase from Moraxella sp. B is similar to that of haloalkane dehalogenase (EC 3.8.1.5) from Xanthobacter autotrophicus GJ10 in the regions around Asp-105 and His-272, which correspond to the active site nucleophile Asp-124 and the base catalyst His-289 of the haloalkane dehalogenase, respectively (Krooshof, G. H., Kwant, E. M., Damborský, J., Koca, J., and Janssen, D. B. (1997) Biochemistry 36, 9571-9580). After multiple turnovers of the fluoroacetate dehalogenase reaction in H218O, the enzyme was digested with trypsin, and the molecular masses of the peptide fragments formed were measured by ion-spray mass spectrometry. Two 18O atoms were shown to be incorporated into the octapeptide, Phe-99-Arg-106. Tandem mass spectrometric analysis of this peptide revealed that Asp-105 was labeled with two 18O atoms. These results indicate that Asp-105 acts as a nucleophile to attack the alpha-carbon of the substrate, leading to the formation of an ester intermediate, which is subsequently hydrolyzed by the nucleophilic attack of a water molecule on the carbonyl carbon atom. A His-272 --> Asn mutant (H272N) showed no activity with either fluoroacetate or chloroacetate. However, ion-spray mass spectrometry revealed that the H272N mutant enzyme was covalently alkylated with the substrate. The reaction of the H272N mutant enzyme with [14C]chloroacetate also showed the incorporation of radioactivity into the enzyme. These results suggest that His-272 probably acts as a base catalyst for the hydrolysis of the covalent ester intermediate.

  18. Molecular Dynamics Simulations of the Anchoring and Tilting of the Lung-Surfactant Peptide SP-B1-25 in Palmitic Acid Monolayers

    PubMed Central

    Lee, Hwankyu; Kandasamy, Senthil K.; Larson, Ronald G.

    2005-01-01

    We have performed molecular dynamics simulations of multiple copies of the lung-surfactant peptide SP-B1-25 in a palmitic acid (PA) monolayer. SP-B1-25 is a shorter version of lung-surfactant protein B, an important component of lung surfactant. Up to 30 ns simulations of 20 wt % SP-B1-25 in the PA monolayers were performed with different surface areas of PA, extents of PA ionization, and various initial configurations of the peptides. Starting with initial peptide orientation perpendicular to the monolayer, the predicted final tilt angles average 54°∼ 62° with respect to the monolayer normal, similar to those measured experimentally by Lee et al. (Biophysical Journal. 2001. Synchrotron x-ray study of lung surfactant-specific protein SP-B in lipid monolayers. 81:572–585). In their final conformations, hydrogen-bond analysis and amino acid mutation studies show that the peptides are anchored by hydrogen bond interactions between the cationic residues Arg-12 and Arg-17 and the hydrogen bond acceptors of the ionized PA headgroup, and the tilt angle is affected by the interactions of Tyr-7 and Gln-19 with the PA headgroup. Our work indicates that the factors controlling orientation of small peptides in lipid layers can now be uncovered through molecular dynamics simulations. PMID:16169980

  19. An antioxidant exopolysaccharide devoid of pro-oxidant activity produced by the soil bacterium Bordetella sp. B4.

    PubMed

    Lin, Yanliang; Liu, Jinglei; Hu, Yibo; Song, Xin; Zhao, Yueran

    2012-11-01

    An exopolysaccharide (EPS) with a molecular weight of 230 kDa, was isolated from Bordetella sp. B4. The EPS was identified as linear alpha-1,6-(6-methyl)-glucan with N-acetyl-D-glucosamine branches at alpha-1, 4-linkages by IR and NMR spectroscopy. The free radical scavenging capacities of EPS on 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS(+)), H(2)O(2), -OH and lipid peroxidation were 2-, 86-, 134- and 18-fold higher than that of ascorbic acid, respectively. Compared with ascorbic acid, the EPS was more effective in preventing DNA and protein from free radical damage induced by 2,2'-azobis (2-amidinopropane) dihydrochloride (AAPH). More significantly, the EPS did not degrade DNA and protein by the pro-oxidant effect in the presence of copper ions and H(2)O(2). Furthermore, EPS could protect human umbilical vein endothelium cells (HUVECs) from high glucose-mediated damage. The production of EPS reached 10.2 g/L in the fermentation medium containing 3.0 g/L cholesterol, suggesting that Bordetella sp. B4 was a potential producer of antioxidant EPS.

  20. Molecular Dynamics Study of the Lung Surfactant Peptide SP-B1–25 with DPPC Monolayers: Insights into Interactions and Peptide Position and Orientation

    PubMed Central

    Kandasamy, Senthil K.; Larson, Ronald G.

    2005-01-01

    We have performed molecular dynamics simulations of the interactions of the peptide SP-B1–25, which is a truncated version of the full pulmonary surfactant protein SP-B, with dipalmitoylphosphatidylcholine monolayers, which are the major lipid components of lung surfactant. Simulations of durations of 10–20 ns show that persistent hydrogen bonds form between the donor atoms of the protein and the acceptors of the lipid headgroup and that these bonds determine the position, orientation, and secondary structure of the peptide in the membrane environment. From an ensemble of initial conditions, the most probable equilibrium orientation of the α-helix of the peptide is predicted to be parallel to the interface, matching recent experimental results on model lipid mixtures. Simulations of a few mutated analogs of SP-B1–25 also suggest that the charged amino acids are important in determining the position of the peptide in the interface. The first eight amino acids of the peptide, also known as the insertion sequence, are found to be essential in reducing the fluctuations and anchoring the peptide in the lipid/water interface. PMID:15738465

  1. Environmentally safe treatment of black liquor with Comamonas sp. B-9 under high-alkaline conditions.

    PubMed

    Zheng, Yu; Chai, Liyuan; Yang, Zhihui; Chen, Yuehui; Shi, Yan; Wang, Yangyang

    2014-02-01

    The strain Comamonas sp. B-9 was isolated from steeping fluid of erosive bamboo slips derived from Kingdom Wu during the Three-Kingdoms Dynasty of ancient China (A.D. 220-280). It could be used to treat black liquor (BL) with high-alkaline pH and with an initial chemical oxygen demand (COD) of 18,000-25,000 mg L(-1) , without the addition of other carbon and nitrogen sources. The results revealed that Comamonas sp. B-9 was capable of reducing the COD, color, and lignin content of BL by up to 56.8, 35.3, and 43.5%, respectively. High levels of laccase, manganese peroxidase, cellulase, and xylanase enzymatic activities were also observed, and these enzymes could play an important role in the biotreatment of BL. Further, GC-MS analysis showed that most of the compounds detected in BL after biotreatment with Comamonas sp. B-9 were diminished, while 4-methyl benzaldehyde, 3,4,5-trihydroxybenzoic acid ethyl ester, and 4-hydroxy-3,5-dimethoxy benzaldehyde were produced as metabolites. The presented results indicate that Comamonas sp. B-9 has potential application for the treatment of wastewaters from pulp and paper processing with high COD load under high-alkaline conditions.

  2. Effect of strong detergents and chaotropes on the detection of proteins in two-dimensional gels.

    PubMed

    Fountoulakis, M; Takács, B

    2001-05-01

    The solubilization of a particular protein is mandatory for its subsequent resolution and detection in two-dimensional gels. However, the extraction solutions, that are compatible with the first-dimensional separation step, such as urea and 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate (CHAPS), do not solubilize all proteins in a sample. We studied the effect of various common, strong detergents and chaotropes, widely used as solubilizing agents, such as sodium dodecyl sulfate, lithium dodecyl sulfate and guanidine hydrochloride, on the solubilization of the total and membrane proteins of the bacterium Haemophilus influenzae. The proteins solubilized with each system were analyzed by two-dimensional electrophoresis and these of interest were identified by matrix assisted laser desorption/ionization-mass spectrometry (MALDI-MS). Use of sodium dodecyl sulfate, lithium dodecyl sulfate or guanidine hydrochloride for the solubilization of total proteins of the microorganism resulted in the detection of several additional spots, representing mainly outer membrane proteins, in comparison with those detected in the soluble protein fraction. Solubilization of the proteins of the cell envelope fraction with sodium dodecyl sulfate did not result in a more efficient protein detection when compared to the extraction with the urea/CHAPS system. When the dry immobilized pH gradient strips were rehydrated in a solution containing the proteins of the membrane fraction solubilized with sodium dodecyl sulfate or lithium dodecyl sulfate, a larger number of protein spots were detected in comparison with strips that were rehydrated in the urea/CHAPS solution. However, no improvement was observed in comparison with protein application in sample cups. The additional proteins detected with the use of strong detergents and chaotropes are in the majority difficult to solubilize and less hydrophobic proteins.

  3. Conjugation Strategy Strongly Impacts the Conformational Stability of a PEG-Protein Conjugate.

    PubMed

    Lawrence, Paul B; Billings, Wendy M; Miller, McKenzie B; Pandey, Brijesh K; Stephens, Andrew R; Langlois, Minnie I; Price, Joshua L

    2016-07-15

    Site-specific PEGylation is an important strategy for enhancing the pharmacokinetic properties of protein drugs, and has been enabled by the recent development of many chemoselective reactions for protein side-chain modification. However, the impact of these different conjugation strategies on the properties of PEG-protein conjugates is poorly understood. Here we show that the ability of PEG to enhance protein conformational stability depends strongly on the identity of the PEG-protein linker, with the most stabilizing linkers involving conjugation of PEG to planar polar groups near the peptide backbone. We also find that branched PEGs provide superior stabilization relative to their linear counterparts, suggesting additional applications for branched PEGs in protein stabilization.

  4. Synthetic surfactant containing SP-B and SP-C mimics is superior to single-peptide formulations in rabbits with chemical acute lung injury.

    PubMed

    Walther, Frans J; Hernández-Juviel, José M; Gordon, Larry M; Waring, Alan J

    2014-01-01

    Background. Chemical spills are on the rise and inhalation of toxic chemicals may induce chemical acute lung injury (ALI)/acute respiratory distress syndrome (ARDS). Although the pathophysiology of ALI/ARDS is well understood, the absence of specific antidotes has limited the effectiveness of therapeutic interventions. Objectives. Surfactant inactivation and formation of free radicals are important pathways in (chemical) ALI. We tested the potential of lipid mixtures with advanced surfactant protein B and C (SP-B and C) mimics to improve oxygenation and lung compliance in rabbits with lavage- and chemical-induced ALI/ARDS. Methods. Ventilated young adult rabbits underwent repeated saline lung lavages or underwent intratracheal instillation of hydrochloric acid to induce ALI/ARDS. After establishment of respiratory failure rabbits were treated with a single intratracheal dose of 100 mg/kg of synthetic surfactant composed of 3% Super Mini-B (S-MB), a SP-B mimic, and/or SP-C33 UCLA, a SP-C mimic, in a lipid mixture (DPPC:POPC:POPG 5:3:2 by weight), the clinical surfactant Infasurf(®), a bovine lung lavage extract with SP-B and C, or synthetic lipids alone. End-points consisted of arterial oxygenation, dynamic lung compliance, and protein and lipid content in bronchoalveolar lavage fluid. Potential mechanism of surfactant action for S-MB and SP-C33 UCLA were investigated with captive bubble surfactometry (CBS) assays. Results. All three surfactant peptide/lipid mixtures and Infasurf equally lowered the minimum surface tension on CBS, and also improved oxygenation and lung compliance. In both animal models, the two-peptide synthetic surfactant with S-MB and SP-C33 UCLA led to better arterial oxygenation and lung compliance than single peptide synthetic surfactants and Infasurf. Synthetic surfactants and Infasurf improved lung function further in lavage- than in chemical-induced respiratory failure, with the difference probably due to greater capillary-alveolar protein

  5. Synthetic surfactant containing SP-B and SP-C mimics is superior to single-peptide formulations in rabbits with chemical acute lung injury

    PubMed Central

    Hernández-Juviel, José M.; Gordon, Larry M.; Waring, Alan J.

    2014-01-01

    Background. Chemical spills are on the rise and inhalation of toxic chemicals may induce chemical acute lung injury (ALI)/acute respiratory distress syndrome (ARDS). Although the pathophysiology of ALI/ARDS is well understood, the absence of specific antidotes has limited the effectiveness of therapeutic interventions. Objectives. Surfactant inactivation and formation of free radicals are important pathways in (chemical) ALI. We tested the potential of lipid mixtures with advanced surfactant protein B and C (SP-B and C) mimics to improve oxygenation and lung compliance in rabbits with lavage- and chemical-induced ALI/ARDS. Methods. Ventilated young adult rabbits underwent repeated saline lung lavages or underwent intratracheal instillation of hydrochloric acid to induce ALI/ARDS. After establishment of respiratory failure rabbits were treated with a single intratracheal dose of 100 mg/kg of synthetic surfactant composed of 3% Super Mini-B (S-MB), a SP-B mimic, and/or SP-C33 UCLA, a SP-C mimic, in a lipid mixture (DPPC:POPC:POPG 5:3:2 by weight), the clinical surfactant Infasurf®, a bovine lung lavage extract with SP-B and C, or synthetic lipids alone. End-points consisted of arterial oxygenation, dynamic lung compliance, and protein and lipid content in bronchoalveolar lavage fluid. Potential mechanism of surfactant action for S-MB and SP-C33 UCLA were investigated with captive bubble surfactometry (CBS) assays. Results. All three surfactant peptide/lipid mixtures and Infasurf equally lowered the minimum surface tension on CBS, and also improved oxygenation and lung compliance. In both animal models, the two-peptide synthetic surfactant with S-MB and SP-C33 UCLA led to better arterial oxygenation and lung compliance than single peptide synthetic surfactants and Infasurf. Synthetic surfactants and Infasurf improved lung function further in lavage- than in chemical-induced respiratory failure, with the difference probably due to greater capillary-alveolar protein

  6. Positive and strongly relaxed purifying selection drive the evolution of repeats in proteins

    PubMed Central

    Persi, Erez; Wolf, Yuri I.; Koonin, Eugene V

    2016-01-01

    Protein repeats are considered hotspots of protein evolution, associated with acquisition of new functions and novel phenotypic traits, including disease. Paradoxically, however, repeats are often strongly conserved through long spans of evolution. To resolve this conundrum, it is necessary to directly compare paralogous (horizontal) evolution of repeats within proteins with their orthologous (vertical) evolution through speciation. Here we develop a rigorous methodology to identify highly periodic repeats with significant sequence similarity, for which evolutionary rates and selection (dN/dS) can be estimated, and systematically characterize their evolution. We show that horizontal evolution of repeats is markedly accelerated compared with their divergence from orthologues in closely related species. This observation is universal across the diversity of life forms and implies a biphasic evolutionary regime whereby new copies experience rapid functional divergence under combined effects of strongly relaxed purifying selection and positive selection, followed by fixation and conservation of each individual repeat. PMID:27857066

  7. Strong Selection Significantly Increases Epistatic Interactions in the Long-Term Evolution of a Protein

    PubMed Central

    Gupta, Aditi; Adami, Christoph

    2016-01-01

    Epistatic interactions between residues determine a protein’s adaptability and shape its evolutionary trajectory. When a protein experiences a changed environment, it is under strong selection to find a peak in the new fitness landscape. It has been shown that strong selection increases epistatic interactions as well as the ruggedness of the fitness landscape, but little is known about how the epistatic interactions change under selection in the long-term evolution of a protein. Here we analyze the evolution of epistasis in the protease of the human immunodeficiency virus type 1 (HIV-1) using protease sequences collected for almost a decade from both treated and untreated patients, to understand how epistasis changes and how those changes impact the long-term evolvability of a protein. We use an information-theoretic proxy for epistasis that quantifies the co-variation between sites, and show that positive information is a necessary (but not sufficient) condition that detects epistasis in most cases. We analyze the “fossils” of the evolutionary trajectories of the protein contained in the sequence data, and show that epistasis continues to enrich under strong selection, but not for proteins whose environment is unchanged. The increase in epistasis compensates for the information loss due to sequence variability brought about by treatment, and facilitates adaptation in the increasingly rugged fitness landscape of treatment. While epistasis is thought to enhance evolvability via valley-crossing early-on in adaptation, it can hinder adaptation later when the landscape has turned rugged. However, we find no evidence that the HIV-1 protease has reached its potential for evolution after 9 years of adapting to a drug environment that itself is constantly changing. We suggest that the mechanism of encoding new information into pairwise interactions is central to protein evolution not just in HIV-1 protease, but for any protein adapting to a changing environment. PMID

  8. Hydrogen production of a salt tolerant strain Bacillus sp. B2 from marine intertidal sludge.

    PubMed

    Liu, Hongyan; Wang, Guangce

    2012-01-01

    To isolate a salt tolerant hydrogen-producing bacterium, we used the sludge from the intertidal zone of a bathing beach in Tianjin as inoculum to enrich hydrogen-producing bacteria. The sludge was treated by heat-shock pretreatment with three different temperature (80, 100 and 121°C) respectively. A hydrogen-producing bacterium was isolated from the sludge pretreated at 80°C by sandwich plate technique and identified using microscopic examination and 16S rDNA gene sequence analysis. The isolated bacterium was named as Bacillus sp. B2. The present study examined the hydrogen-producing ability of Bacillus sp. B2. The strain was able to produce hydrogen over a wide range of initial pH from 5.0 to 10.0, with an optimum at pH 7.0. The level of hydrogen production was also affected by the salt concentration. Strain B2 has unique capability to adapt high salt concentration. It could produce hydrogen at the salt concentration from 4 to 60‰. The maximum of hydrogen-producing yield of strain B2 was 1.65 ± 0.04 mol H(2)/mol glucose (mean ± SE) at an initial pH value of 7.0 in marine culture conditions. Hydrogen production under fresh culture conditions reached a higher level than that in marine ones. As a result, it is likely that Bacillus sp. B2 could be applied to biohydrogen production using both marine and fresh organic waste.

  9. Strong cation-exchange chromatography of proteins on a sulfoalkylated monolithic cryogel.

    PubMed

    Perçin, Işık; Khalaf, Rushd; Brand, Bastian; Morbidelli, Massimo; Gezici, Orhan

    2015-03-20

    A new strong cation exchanger (SCX) monolithic column was synthesized by at-line surface modification of a cryogel prepared by copolymerization of 2-hydroxyethylmethacrylate (HEMA) and glycidylmethacrylate (GMA). Sodium salt of 3-Mercaptopropane sulfonic acid (3-MPS) was used as the ligand to transform the surface of the monolith into a strong cation exchanger. The obtained material was characterized in terms of elemental analysis, infrared spectroscopy (FTIR), Scanning Electron Microscopy (SEM), Brunauer-Emmett-Teller (BET) N2 adsorption, and used as a stationary phase for strong-cation exchange chromatography of some proteins, such as α-chymotrypsinogen, cytochrome c and lysozyme. Water permeability of the column was calculated according to Darcy's law (2.66×10(-13)m(2)). The performance of the monolithic cryogel column was evaluated on the basis of Height Equivalent to a Theoretical Plate (HETP). Retention behavior of the studied proteins was modeled on the basis of Yamamoto model to understand the role of the ion-exchange mechanism in retention behaviors. The considered proteins were successfully separated, and the obtained chromatogram was compared with that obtained with a non-functionalized cryogel column.

  10. Discovery of a super-strong promoter enables efficient production of heterologous proteins in cyanobacteria.

    PubMed

    Zhou, Jie; Zhang, Haifeng; Meng, Hengkai; Zhu, Yan; Bao, Guanhui; Zhang, Yanping; Li, Yin; Ma, Yanhe

    2014-03-28

    Cyanobacteria are oxygenic photosynthetic prokaryotes that play important roles in the global carbon cycle. Recently, engineered cyanobacteria capable of producing various small molecules from CO2 have been developed. However, cyanobacteria are seldom considered as factories for producing proteins, mainly because of the lack of efficient strong promoters. Here, we report the discovery and verification of a super-strong promoter P(cpc560), which contains two predicted promoters and 14 predicted transcription factor binding sites (TFBSs). Using P(cpc560), functional proteins were produced at a level of up to 15% of total soluble protein in the cyanobacterium Synechocystis sp. 6803, a level comparable to that produced in Escherichia coli. We demonstrated that the presence of multiple TFBSs in P(cpc560) is crucial for its promoter strength. Genetically transformable cyanobacteria neither have endotoxins nor form inclusion bodies; therefore, P(cpc560) opens the possibility to use cyanobacteria as alternative hosts for producing heterogeneous proteins from CO2 and inorganic nutrients.

  11. Embedded proteins and sacrificial bonds provide the strong adhesive properties of gastroliths

    NASA Astrophysics Data System (ADS)

    Thormann, Esben; MizunoPresent Address: Nihon L'Oreal, Research; Innovation Center, 3-2-1 Sakado, Takatsu, Kawasaki, Kanagawa, Japan., Hiroyasu; Jansson, Kjell; Hedin, Niklas; Fernández, M. Soledad; Arias, José Luis; Rutland, Mark W.; PaiPresent Address: CenterFunctional Nanomaterials, Brookhaven National Laboratory, 735 Brookhaven Avenue, Upton, New York 11973., Ranjith Krishna; Bergström, Lennart

    2012-06-01

    The adhesive properties of gastroliths from a freshwater crayfish (Cherax quadricarinatus) were quantified by colloidal probe atomic force microscopy (AFM) between heavily demineralized gastrolith microparticles and gastrolith substrates of different composition. Combined AFM and transmission electron microscopy studies demonstrated that the sequential detachment and large adhesion energies that characterise the adhesive behaviour of a native gastrolith substrate are dominated by sacrificial bonds between chitin fibres and between chitin fibres and CaCO3. The sacrificial bonds were shown to be strongly related to the gastrolith proteins and when the majority of these proteins were removed by ethylenediaminetetraacetic acid (EDTA), the sequential detachment disappeared and the adhesive energy was reduced by more than two orders of magnitude.The adhesive properties of gastroliths from a freshwater crayfish (Cherax quadricarinatus) were quantified by colloidal probe atomic force microscopy (AFM) between heavily demineralized gastrolith microparticles and gastrolith substrates of different composition. Combined AFM and transmission electron microscopy studies demonstrated that the sequential detachment and large adhesion energies that characterise the adhesive behaviour of a native gastrolith substrate are dominated by sacrificial bonds between chitin fibres and between chitin fibres and CaCO3. The sacrificial bonds were shown to be strongly related to the gastrolith proteins and when the majority of these proteins were removed by ethylenediaminetetraacetic acid (EDTA), the sequential detachment disappeared and the adhesive energy was reduced by more than two orders of magnitude. Electronic supplementary information (ESI) available. See DOI: 10.1039/c2nr30536d

  12. Cell and protein compatible 3D bioprinting of mechanically strong constructs for bone repair.

    PubMed

    Sawkins, M J; Mistry, P; Brown, B N; Shakesheff, K M; Bonassar, L J; Yang, J

    2015-07-02

    Rapid prototyping of bone tissue engineering constructs often utilizes elevated temperatures, organic solvents and/or UV light for materials processing. These harsh conditions may prevent the incorporation of cells and therapeutic proteins in the fabrication processes. Here we developed a method for using bioprinting to produce constructs from a thermoresponsive microparticulate material based on poly(lactic-co-glycolic acid) at ambient conditions. These constructs could be engineered with yield stresses of up to 1.22 MPa and Young's moduli of up to 57.3 MPa which are within the range of properties of human cancellous bone. Further study showed that protein-releasing microspheres could be incorporated into the bioprinted constructs. The release of the model protein lysozyme from bioprinted constructs was sustainted for a period of 15 days and a high degree of protein activity could be measured up to day 9. This work suggests that bioprinting is a viable route to the production of mechanically strong constructs for bone repair under mild conditions which allow the inclusion of viable cells and active proteins.

  13. General Strategy for the Bioorthogonal Incorporation of Strongly Absorbing, Solvation-Sensitive Infrared Probes into Proteins

    PubMed Central

    2015-01-01

    A high-sensitivity metal-carbonyl-based IR probe is described that can be incorporated into proteins or other biomolecules in very high yield via Click chemistry. A two-step strategy is demonstrated. First, a methionine auxotroph is used to incorporate the unnatural amino acid azidohomoalanine at high levels. Second, a tricarbonyl (η5-cyclopentadienyl) rhenium(I) probe modified with an alkynyl linkage is coupled via the Click reaction. We demonstrate these steps using the C-terminal domain of the ribosomal protein L9 as a model system. An overall incorporation level of 92% was obtained at residue 109, which is a surface-exposed residue. Incorporation of the probe into a surface site is shown not to perturb the stability or structure of the target protein. Metal carbonyls are known to be sensitive to solvation and protein electrostatics through vibrational lifetimes and frequency shifts. We report that the frequencies and lifetimes of this probe also depend on the isotopic composition of the solvent. Comparison of the lifetimes measured in H2O versus D2O provides a probe of solvent accessibility. The metal carbonyl probe reported here provides an easy and robust method to label very large proteins with an amino-acid-specific tag that is both environmentally sensitive and a very strong absorber. PMID:24749542

  14. Strong underwater adhesives made by self-assembling multi-protein nanofibres.

    PubMed

    Zhong, Chao; Gurry, Thomas; Cheng, Allen A; Downey, Jordan; Deng, Zhengtao; Stultz, Collin M; Lu, Timothy K

    2014-10-01

    Many natural underwater adhesives harness hierarchically assembled amyloid nanostructures to achieve strong and robust interfacial adhesion under dynamic and turbulent environments. Despite recent advances, our understanding of the molecular design, self-assembly and structure-function relationships of these natural amyloid fibres remains limited. Thus, designing biomimetic amyloid-based adhesives remains challenging. Here, we report strong and multi-functional underwater adhesives obtained from fusing mussel foot proteins (Mfps) of Mytilus galloprovincialis with CsgA proteins, the major subunit of Escherichia coli amyloid curli fibres. These hybrid molecular materials hierarchically self-assemble into higher-order structures, in which, according to molecular dynamics simulations, disordered adhesive Mfp domains are exposed on the exterior of amyloid cores formed by CsgA. Our fibres have an underwater adhesion energy approaching 20.9 mJ m(-2), which is 1.5 times greater than the maximum of bio-inspired and bio-derived protein-based underwater adhesives reported thus far. Moreover, they outperform Mfps or curli fibres taken on their own and exhibit better tolerance to auto-oxidation than Mfps at pH ≥ 7.0.

  15. Strong underwater adhesives made by self-assembling multi-protein nanofibres

    NASA Astrophysics Data System (ADS)

    Zhong, Chao; Gurry, Thomas; Cheng, Allen A.; Downey, Jordan; Deng, Zhengtao; Stultz, Collin M.; Lu, Timothy K.

    2014-10-01

    Many natural underwater adhesives harness hierarchically assembled amyloid nanostructures to achieve strong and robust interfacial adhesion under dynamic and turbulent environments. Despite recent advances, our understanding of the molecular design, self-assembly and structure-function relationships of these natural amyloid fibres remains limited. Thus, designing biomimetic amyloid-based adhesives remains challenging. Here, we report strong and multi-functional underwater adhesives obtained from fusing mussel foot proteins (Mfps) of Mytilus galloprovincialis with CsgA proteins, the major subunit of Escherichia coli amyloid curli fibres. These hybrid molecular materials hierarchically self-assemble into higher-order structures, in which, according to molecular dynamics simulations, disordered adhesive Mfp domains are exposed on the exterior of amyloid cores formed by CsgA. Our fibres have an underwater adhesion energy approaching 20.9 mJ m-2, which is 1.5 times greater than the maximum of bio-inspired and bio-derived protein-based underwater adhesives reported thus far. Moreover, they outperform Mfps or curli fibres taken on their own and exhibit better tolerance to auto-oxidation than Mfps at pH ≥ 7.0.

  16. Study of Fluid Flow Control In Protein Crystallization Using Strong Magnetic Fields

    NASA Technical Reports Server (NTRS)

    Ramachandran, N.; Leslie, F.; Ciszak, E.; Curreri, Peter A. (Technical Monitor)

    2002-01-01

    An important component in biotechnology, particularly in the area of protein engineering and rational drug design is the knowledge of the precise three-dimensional molecular structure of proteins. The quality of structural information obtained from X-ray diffraction methods is directly dependent on the degree of perfection of the protein crystals. As a consequence, the growth of high quality macromolecular crystals for diffraction analyses has been the central focus for biochemists, biologists, and bioengineers. Macromolecular crystals are obtained from solutions that contain the crystallizing species in equilibrium with higher aggregates, ions, precipitants, other possible phases of the protein, foreign particles, the walls of the container, and a likely host of other impurities. By changing transport modes in general, i.e., reduction of convection and sedimentation, as is achieved in 'microgravity', researchers have been able to dramatically affect the movement and distribution of macromolecules in the fluid, and thus their transport, formation of crystal nuclei, and adsorption to the crystal surface. While a limited number of high quality crystals from space flights have been obtained, as the recent National Research Council (NRC) review of the NASA microgravity crystallization program pointed out, the scientific approach and research in crystallization of proteins has been mainly empirical yielding inconclusive results. We postulate that we can reduce convection in ground-based experiments and we can understand the different aspects of convection control through the use of strong magnetic fields and field gradients. Whether this limited convection in a magnetic field will provide the environment for the growth of high quality crystals is still a matter of conjecture that our research will address. The approach exploits the variation of fluid magnetic susceptibility with concentration for this purpose and the convective damping is realized by appropriately

  17. Molecular cloning of mouse erythrocyte protein 4.2: a membrane protein with strong homology with the transglutaminase supergene family.

    PubMed

    Rybicki, A C; Schwartz, R S; Qiu, J J; Gilman, J G

    1994-07-01

    We report the molecular cloning and characterization of mouse erythrocyte protein 4.2 (P4.2). Mouse erythrocyte P4.2 is a 691-amino-acid protein with a predicted MW of 77 kDa. Northern blot analysis detected a 2.2-kb transcript in mouse reticulocytes, compared with a 2.4- to 2.5-kb transcript in human reticulocytes, which is consistent with the absence of the 30-amino-acid splicing insert in mouse erythrocyte P4.2 that is found in the human protein (isoform I). Like the human erythrocyte P4.2, mouse erythrocyte P4.2 contains regions strikingly homologous with the transglutaminase (TGase) proteins although it too most likely lacks TGase crosslinking activity. Mouse P4.2 is on average 73% identical with human erythrocyte P4.2, although regional variations exist, with greatest conservation in the regions of the molecule that contain the TGase active site, the TGase calcium-binding site, and a band 3 binding site. Hydropathy analysis reveals a protein containing a series of hydrophobic domains, similar to the situation for human P4.2 and consistent with its tight binding to the membrane, although the mouse P4.2 is missing both the strongly hydrophilic region and adjacent highly charged region that are present in the human protein, suggesting that the two proteins could differ in their physical characteristics, binding associations, or functional properties. The availability of the complete mouse erythrocyte P4.2 cDNA should help in the design of P4.2-deficient animal models (for example, ribozyme or homologous recombinant "knockout" models) that should accelerate the understanding of P4.2 function in both erythroid and non-erythroid cells.

  18. Differential susceptibility of transgenic mice expressing human surfactant protein B genetic variants to Pseudomonas aeruginosa induced pneumonia

    PubMed Central

    Ge, Lin; Liu, Xinyu; Chen, Rimei; Xu, Yongan; Zuo, Yi Y.; Cooney, Robert N; Wang, Guirong

    2015-01-01

    Surfactant protein B (SP-B) is essential for lung function. Previous studies have indicated that a SP-B 1580C/T polymorphism (SNP rs1130866) was associated with lung diseases including pneumonia. The SNP causes an altered N-linked glycosylation modification at Asn129 of proSP-B, e.g. the C allele with this glycosylation site but not in the T allele. This study aimed to generate humanized SP-B transgenic mice carrying either SP-B C or T allele without a mouse SP-B background and then examine functional susceptibility to bacterial pneumonia in vivo. A total of 18 transgenic mouse founders were generated by the DNA microinjection method. These founders were back-crossed with SP-B KO mice to eliminate mouse SP-B background. Four founder lines expressing similar SP-B levels to human lung were chosen for further investigation. After intratracheal infection with 50μl of P. aeruginosa solution (1×107 CFU/mouse) or saline in SP-B-C, SP-B-T mice the mice were sacrificed 24 hours post-infection and tissues were harvested. Analysis of surfactant activity revealed differential susceptibility between SP-B-C and SP-B-T mice to bacterial infection, e.g. higher minimum surface tension in infected SP-B-C versus infected SP-B-T mice. These results demonstrate for the first time that human SP-B C allele is more susceptible to bacterial pneumonia than SP-B T allele in vivo. PMID:26620227

  19. L233P mutation of the Tax protein strongly correlated with leukemogenicity of bovine leukemia virus.

    PubMed

    Inoue, Emi; Matsumura, Keiko; Soma, Norihiko; Hirasawa, Shintaro; Wakimoto, Mayuko; Arakaki, Yoshihiro; Yoshida, Takashi; Osawa, Yoshiaki; Okazaki, Katsunori

    2013-12-27

    The bovine leukemia virus (BLV) Tax protein is believed to play a crucial role in leukemogenesis by the virus. BLV usually causes asymptomatic infections in cattle, but only one-third develop persistent lymphocytosis that rarely progress after a long incubation period to lymphoid tumors, namely enzootic bovine leucosis (EBL). In the present study, we demonstrated that the BLV tax genes could be divided into two alleles and developed multiplex PCR detecting an L233P mutation of the Tax protein. Then, in order to define the relationship between the Tax protein and leukemogenicity, we examined 360 tumor samples randomly collected from dairy or breeding cattle in Japan, of which Tax proteins were categorized, for age at the time of diagnosis of EBL. The ages of 288 animals (80.0%) associated with L233-Tax and those of 70 animals (19.4%) with P233-Tax individually followed log-normal distributions. Only the two earliest cases (0.6%) with L233-Tax disobeyed the log-normal distribution. These findings suggest that the animals affected by EBL were infected with the virus at a particular point in life, probably less than a few months after birth. Median age of those with P233-Tax was 22 months older than that with L233-Tax and geometric means exhibited a significant difference (P<0.01). It is also quite unlikely that viruses carrying the particular Tax protein infect older cattle. Here, we conclude that BLV could be divided into two categories on the basis of amino acid at position 233 of the Tax protein, which strongly correlated with leukemogenicity.

  20. The General Phosphotransferase System Proteins Localize to Sites of Strong Negative Curvature in Bacterial Cells

    PubMed Central

    Govindarajan, Sutharsan; Elisha, Yair; Nevo-Dinur, Keren; Amster-Choder, Orna

    2013-01-01

    ABSTRACT The bacterial cell poles are emerging as subdomains where many cellular activities take place, but the mechanisms for polar localization are just beginning to unravel. The general phosphotransferase system (PTS) proteins, enzyme I (EI) and HPr, which control preferential use of carbon sources in bacteria, were recently shown to localize near the Escherichia coli cell poles. Here, we show that EI localization does not depend on known polar constituents, such as anionic lipids or the chemotaxis receptors, and on the cell division machinery, nor can it be explained by nucleoid occlusion or localized translation. Detection of the general PTS proteins at the budding sites of endocytotic-like membrane invaginations in spherical cells and their colocalization with the negative curvature sensor protein DivIVA suggest that geometric cues underlie localization of the PTS system. Notably, the kinetics of glucose uptake by spherical and rod-shaped E. coli cells are comparable, implying that negatively curved “pole-like” sites support not only the localization but also the proper functioning of the PTS system in cells with different shapes. Consistent with the curvature-mediated localization model, we observed the EI protein from Bacillus subtilis at strongly curved sites in both B. subtilis and E. coli. Taken together, we propose that changes in cell architecture correlate with dynamic survival strategies that localize central metabolic systems like the PTS to subcellular domains where they remain active, thus maintaining cell viability and metabolic alertness. PMID:24129255

  1. Study of Fluid Flow Control in Protein Crystallization using Strong Magnetic Fields

    NASA Technical Reports Server (NTRS)

    Ramachandran, Narayanan; Leslie, Fred; Ciszak, Ewa

    2002-01-01

    An important component in biotechnology, particularly in the area of protein engineering and rational drug design is the knowledge of the precise three-dimensional molecular structure of proteins. The quality of structural information obtained from X-ray diffraction methods is directly dependent on the degree of perfection of the protein crystals. As a consequence, the growth of high quality macromolecular crystals for diffraction analyses has been the central focus for biochemists, biologists, and bioengineers. Macromolecular crystals are obtained from solutions that contain the crystallizing species in equilibrium with higher aggregates, ions, precipitants, other possible phases of the protein, foreign particles, the walls of the container, and a likely host of other impurities. By changing transport modes in general, i.e., reduction of convection and sedimentation, as is achieved in "microgravity", researchers have been able to dramatically affect the movement and distribution of macromolecules in the fluid, and thus their transport, formation of crystal nuclei, and adsorption to the crystal surface. While a limited number of high quality crystals from space flights have been obtained, as the recent National Research Council (NRC) review of the NASA microgravity crystallization program pointed out, the scientific approach and research in crystallization of proteins has been mainly empirical yielding inconclusive results. We postulate that we can reduce convection in ground-based experiments and we can understand the different aspects of convection control through the use of strong magnetic fields and field gradients. Whether this limited convection in a magnetic field will provide the environment for the growth of high quality crystals is still a matter of conjecture that our research will address. The approach exploits the variation of fluid magnetic susceptibility with concentration for this purpose and the convective damping is realized by appropriately

  2. Dimethyl disulfide produced by the naturally associated bacterium bacillus sp B55 promotes Nicotiana attenuata growth by enhancing sulfur nutrition.

    PubMed

    Meldau, Dorothea G; Meldau, Stefan; Hoang, Long H; Underberg, Stefanie; Wünsche, Hendrik; Baldwin, Ian T

    2013-07-01

    Bacillus sp B55, a bacterium naturally associated with Nicotiana attenuata roots, promotes growth and survival of wild-type and, particularly, ethylene (ET)-insensitive (35)S-ethylene response1 (etr1) N. attenuata plants, which heterologously express the mutant Arabidopsis thaliana receptor ETR1-1. We found that the volatile organic compound (VOC) blend emitted by B55 promotes seedling growth, which is dominated by the S-containing compound dimethyl disulfide (DMDS). DMDS was depleted from the headspace during cocultivation with seedlings in bipartite Petri dishes, and (35)S was assimilated from the bacterial VOC bouquet and incorporated into plant proteins. In wild-type and (35)S-etr1 seedlings grown under different sulfate (SO(4)(-2)) supply conditions, exposure to synthetic DMDS led to genotype-dependent plant growth promotion effects. For the wild type, only S-starved seedlings benefited from DMDS exposure. By contrast, growth of (35)S-etr1 seedlings, which we demonstrate to have an unregulated S metabolism, increased at all SO(4)(-2) supply rates. Exposure to B55 VOCs and DMDS rescued many of the growth phenotypes exhibited by ET-insensitive plants, including the lack of root hairs, poor lateral root growth, and low chlorophyll content. DMDS supplementation significantly reduced the expression of S assimilation genes, as well as Met biosynthesis and recycling. We conclude that DMDS by B55 production is a plant growth promotion mechanism that likely enhances the availability of reduced S, which is particularly beneficial for wild-type plants growing in S-deficient soils and for (35)S-etr1 plants due to their impaired S uptake/assimilation/metabolism.

  3. Strong precursor-pore interactions constrain models for mitochondrial protein import.

    PubMed Central

    Chauwin, J F; Oster, G; Glick, B S

    1998-01-01

    Mitochondrial precursor proteins are imported from the cytosol into the matrix compartment through a proteinaceous translocation pore. Import is driven by mitochondrial Hsp70 (mHsp70), a matrix-localized ATPase. There are currently two postulated mechanisms for this function of mHsp70: 1) The "Brownian ratchet" model proposes that the precursor chain diffuses within the pore, and that binding of mHsp70 to the lumenal portion of the chain biases this diffusion. 2) The "power stroke" model proposes that mHsp70 undergoes a conformational change that actively pulls the precursor chain through the pore. Here we formulate these two models quantitatively, and compare their performance in light of recent experimental evidence that precursor chains interact strongly with the walls of the translocation pore. Under these conditions the simulated Brownian ratchet is inefficient, whereas the power stroke mechanism seems to be a plausible description of the import process. PMID:9545036

  4. Study of Fluid Flow Control in Protein Crystallization using Strong Magnetic Fields

    NASA Astrophysics Data System (ADS)

    Ramachandran, Narayanan; Leslie, Fred; Ciszak, Ewa

    2002-11-01

    An important component in biotechnology, particularly in the area of protein engineering and rational drug design is the knowledge of the precise three-dimensional molecular structure of proteins. The quality of structural information obtained from X-ray diffraction methods is directly dependent on the degree of perfection of the protein crystals. As a consequence, the growth of high quality macromolecular crystals for diffraction analyses has been the central focus for biochemists, biologists, and bioengineers. Macromolecular crystals are obtained from solutions that contain the crystallizing species in equilibrium with higher aggregates, ions, precipitants, other possible phases of the protein, foreign particles, the walls of the container, and a likely host of other impurities. By changing transport modes in general, i.e., reduction of convection and sedimentation, as is achieved in "microgravity", researchers have been able to dramatically affect the movement and distribution of macromolecules in the fluid, and thus their transport, formation of crystal nuclei, and adsorption to the crystal surface. While a limited number of high quality crystals from space flights have been obtained, as the recent National Research Council (NRC) review of the NASA microgravity crystallization program pointed out, the scientific approach and research in crystallization of proteins has been mainly empirical yielding inconclusive results. We postulate that we can reduce convection in ground-based experiments and we can understand the different aspects of convection control through the use of strong magnetic fields and field gradients. Whether this limited convection in a magnetic field will provide the environment for the growth of high quality crystals is still a matter of conjecture that our research will address. The approach exploits the variation of fluid magnetic susceptibility with concentration for this purpose and the convective damping is realized by appropriately

  5. Study of Fluid Flow Control in Protein Crystallization using Strong Magnetic Fields

    NASA Technical Reports Server (NTRS)

    Ramachandran, Narayanan; Leslie, Fred; Ciszak, Ewa

    2002-01-01

    An important component in biotechnology, particularly in the area of protein engineering and rational drug design is the knowledge of the precise three-dimensional molecular structure of proteins. The quality of structural information obtained from X-ray diffraction methods is directly dependent on the degree of perfection of the protein crystals. As a consequence, the growth of high quality macromolecular crystals for diffraction analyses has been the central focus for biochemists, biologists, and bioengineers. Macromolecular crystals are obtained from solutions that contain the crystallizing species in equilibrium with higher aggregates, ions, precipitants, other possible phases of the protein, foreign particles, the walls of the container, and a likely host of other impurities. By changing transport modes in general, i.e., reduction of convection and sedimentation, as is achieved in "microgravity", researchers have been able to dramatically affect the movement and distribution of macromolecules in the fluid, and thus their transport, formation of crystal nuclei, and adsorption to the crystal surface. While a limited number of high quality crystals from space flights have been obtained, as the recent National Research Council (NRC) review of the NASA microgravity crystallization program pointed out, the scientific approach and research in crystallization of proteins has been mainly empirical yielding inconclusive results. We postulate that we can reduce convection in ground-based experiments and we can understand the different aspects of convection control through the use of strong magnetic fields and field gradients. Whether this limited convection in a magnetic field will provide the environment for the growth of high quality crystals is still a matter of conjecture that our research will address. The approach exploits the variation of fluid magnetic susceptibility with concentration for this purpose and the convective damping is realized by appropriately

  6. Identification, cloning, and expression of L-amino acid oxidase from marine Pseudoalteromonas sp. B3.

    PubMed

    Yu, Zhiliang; Zhou, Ning; Qiao, Hua; Qiu, Juanping

    2014-01-01

    L-amino acid oxidase (LAAO) is attracting more attentions due to its broad and important biological functions. Recently, an LAAO-producing marine microorganism (strain B3) was isolated from the intertidal zone of Dinghai sea area, China. Physiological, biochemical, and molecular identifications together with phylogenetic analysis congruously suggested that it belonged to the genus Pseudoalteromonas. Therefore, it was designated as Pseudoalteromonas sp. B3. Its capability of LAAO production was crossly confirmed by measuring the products of H2O2, a-keto acids, and NH4+ in oxidization reaction. Two rounds of PCR were performed to gain the entire B3-LAAO gene sequence of 1608 bps in length encoding for 535 amino acid residues. This deduced amino acid sequence showed 60 kDa of the calculated molecular mass, supporting the SDS-PAGE result. Like most of flavoproteins, B3-LAAO also contained two conserved typical motifs, GG-motif and βαβ-dinucleotide-binding domain motif. On the other hand, its unique substrate spectra and sequence information suggested that B3-LAAO was a novel LAAO. Our results revealed that it could be functionally expressed in E. coli BL21(DE3) using vectors, pET28b(+) and pET20b(+). However, compared with the native LAAO, the expression level of the recombinant one was relatively low, most probably due to the formation of inclusion bodies. Several solutions are currently being conducted in our lab to increase its expression level.

  7. Chromium (VI) detoxification by oxidation and flocculation of exopolysaccharides from Arthrobacter sp. B4.

    PubMed

    Li, Yumei; Li, Qiang; Fengying, Yang; Bao, Jie; Hu, Zhiheng; Zhu, Wenwen; Zhao, Yueyue; Lin, Zhaodang; Dong, Qingsheng

    2015-11-01

    The exopolysaccharides from Arthrobacter sp. B4 (B4-EPS) exhibited an excellent chromium (VI) (Cr(VI)) removal capability without any pH adjustment, whereby 50mgL(-1) of Cr(VI) could be completely removed by 4gL(-1) of B4-EPS. The kinetics tests revealed that the first-order rate constant was 8.3×10(-5)s(-1) and the optimal reaction time was 720min. However, a low initial concentration of Cr(VI) (5-30mgL(-1)) would accelerate the reaction rate of Cr(VI) removal and shorten reaction time to less than 360min. Meanwhile, the X-ray photoelectron spectroscopy (XPS) and ultraviolet-visible (UV-vis) spectra indicated that Cr(VI) was reduced to Cr(III) by B4-EPS in accordance with the emergence of the green reaction products. Furthermore, the Fourier transform-infrared spectra (FT-IR) and nuclear magnetic resonance (NMR) showed that carboxyl and hydroxyl groups of B4-EPS contributed to Cr(VI) reduction. Additionally, a feasible scheme for Cr(VI) detoxification by oxidation and flocculation of B4-EPS is presented.

  8. Two Novel Antioxidant Nonapeptides from Protein Hydrolysate of Skate (Raja porosa) Muscle

    PubMed Central

    Hu, Fa-Yuan; Chi, Chang-Feng; Wang, Bin; Deng, Shang-Gui

    2015-01-01

    In the current study, the preparation conditions of neutrase hydrolysate (SMH) from skate (Raja porosa) muscle protein were optimized using orthogonal L9(3)4 tests, and R values indicated that pH was the most important factor affecting HO· scavenging activity of SMH. Under the optimum conditions of pH 7.0, enzymolysis temperature 60 °C, enzyme/substrate ratio (E/S) 2%, and enzymolysis time 5 h, EC50 of SMH on HO· was 2.14 ± 0.17 mg/mL. Using ultrafiltration, gel filtration chromatography, and RP-HPLC, two novel antioxidant nonapeptides (SP-A and SP-B) were isolated from SMH and their amino acid sequences were found to be APPTAYAQS (SP-A) and NWDMEKIWD (SP-B) with calculated molecular masses of 904.98 Da and 1236.38 Da, respectively. Both showed strong antioxidant activities. SP-A and SP-B exhibited good scavenging activities on HO· (EC50 0.390 and 0.176 mg/mL), DPPH· (EC50 0.614 and 0.289 mg/mL), and O2−· (EC50 0.215 and 0.132 mg/mL) in a dose-dependent manner. SP-B was also effective against lipid peroxidation in the model system. The aromatic (2Trp), acidic (2Asp and Glu), and basic (Lys) amino acid residues within the sequences of SP-B might account for its pronounced antioxidant activity. The results of this study suggested that protein hydrolysate and peptides from skate muscle might be effective as food additives for retarding lipid peroxidation occurring in foodstuffs. PMID:25854645

  9. Two novel antioxidant nonapeptides from protein hydrolysate of skate (Raja porosa) muscle.

    PubMed

    Hu, Fa-Yuan; Chi, Chang-Feng; Wang, Bin; Deng, Shang-Gui

    2015-04-03

    In the current study, the preparation conditions of neutrase hydrolysate (SMH) from skate (Raja porosa) muscle protein were optimized using orthogonal L9(3)4 tests, and R values indicated that pH was the most important factor affecting HO· scavenging activity of SMH. Under the optimum conditions of pH 7.0, enzymolysis temperature 60 °C, enzyme/substrate ratio (E/S) 2%, and enzymolysis time 5 h, EC50 of SMH on HO· was 2.14 ± 0.17 mg/mL. Using ultrafiltration, gel filtration chromatography, and RP-HPLC, two novel antioxidant nonapeptides (SP-A and SP-B) were isolated from SMH and their amino acid sequences were found to be APPTAYAQS (SP-A) and NWDMEKIWD (SP-B) with calculated molecular masses of 904.98 Da and 1236.38 Da, respectively. Both showed strong antioxidant activities. SP-A and SP-B exhibited good scavenging activities on HO· (EC50 0.390 and 0.176 mg/mL), DPPH· (EC50 0.614 and 0.289 mg/mL), and O2-· (EC50 0.215 and 0.132 mg/mL) in a dose-dependent manner. SP-B was also effective against lipid peroxidation in the model system. The aromatic (2Trp), acidic (2Asp and Glu), and basic (Lys) amino acid residues within the sequences of SP-B might account for its pronounced antioxidant activity. The results of this study suggested that protein hydrolysate and peptides from skate muscle might be effective as food additives for retarding lipid peroxidation occurring in foodstuffs.

  10. FTIR investigation of the effects of ultra-strong static magnetic field on the secondary structures of protein in bacteria

    NASA Astrophysics Data System (ADS)

    She, Zichao; Hu, Xing; Zhao, Xusheng; Ren, Zhongming; Ding, Guoji

    2009-07-01

    Secondary structures of protein in Escherichia coli ( E. coli) and Staphylococcus aureus ( S. aureus) exposed to the ultra-strong static magnetic field (SMF) were investigated by Fourier transformation infrared spectroscopy (FTIR). Difference index D value of amide I (1600-1700 cm -1) showed that the ultra-strong magnetic field had little impact on S. aureus, but had strong impact on E. coli. The results indicated that 3.46-9.92% of the disorder coils in the secondary structures of protein in E. coli were turned into α-helices under SMF while applying deconvolution and curve fitting to amide I. At the same time, intermolecular β-sheets transforming into intramolecular ones suggested that cohesion among protein molecules had been destroyed and intramolecular hydrogen bonds strengthened. All the differences among the compositions of protein's secondary structures in E. coli were mostly due to the varying degrees of various proteins affected by the magnetic field. The results may provide new insights into the structural changes of proteins induced by the SMF.

  11. New Method for Measuring the Anchoring Energy of Strongly-Bound Membrane-Associated Proteins [Method for measuring the anchoring energy of strongly-bound membrane-associated proteins].

    SciTech Connect

    Kent, Michael S.; La Bauve, Elisa; Vernon, Briana C.; Ye, Dongmei; Rogers, David M.; Siegrist, Cathryn M.; Carson, Bryan; Rempe, Susan L.; Zheng, Aihua; Kielian, Margaret; Schreve, Andrew P.

    2016-02-01

    Here, we describe a new method to measure the activation energy required to remove a strongly-bound membrane-associated protein from a lipid membrane (anchoring energy). It is based on measuring the rate of release of a liposome-bound protein during centrifugation on a sucrose gradient as a function of time and temperature. The method was used to determine anchoring energy for the soluble dengue virus envelope protein (sE) strongly bound to 80:20 POPC:POPG liposomes at pH 5.5. We also measured the binding energy of sE at the same pH for the initial, predominantly reversible, phase of binding to a 70:30 PC:PG lipid bilayer. The anchoring energy (37 +/- 1.7 kcal/mol, 20% PG) was found to be much larger than the binding energy (7.8 +/- 0.3 kcal/mol for 30% PG, or est. 7.0 kcal/mol for 20% PG). This is consistent with data showing that free sE is a monomer at pH 5.5, but assembles into trimers after associating with membranes. But, trimerization alone is insufficient to account for the observed difference in energies, and we conclude that some energy dissipation occurs during the release process. This new method to determine anchoring energy should be useful to understand the complex interactions of integral monotopic proteins and strongly-bound peripheral membrane proteins with lipid membranes.

  12. Cooperative folding of intrinsically disordered domains drives assembly of a strong elongated protein

    NASA Astrophysics Data System (ADS)

    Gruszka, Dominika T.; Whelan, Fiona; Farrance, Oliver E.; Fung, Herman K. H.; Paci, Emanuele; Jeffries, Cy M.; Svergun, Dmitri I.; Baldock, Clair; Baumann, Christoph G.; Brockwell, David J.; Potts, Jennifer R.; Clarke, Jane

    2015-06-01

    Bacteria exploit surface proteins to adhere to other bacteria, surfaces and host cells. Such proteins need to project away from the bacterial surface and resist significant mechanical forces. SasG is a protein that forms extended fibrils on the surface of Staphylococcus aureus and promotes host adherence and biofilm formation. Here we show that although monomeric and lacking covalent cross-links, SasG maintains a highly extended conformation in solution. This extension is mediated through obligate folding cooperativity of the intrinsically disordered E domains that couple non-adjacent G5 domains thermodynamically, forming interfaces that are more stable than the domains themselves. Thus, counterintuitively, the elongation of the protein appears to be dependent on the inherent instability of its domains. The remarkable mechanical strength of SasG arises from tandemly arrayed `clamp' motifs within the folded domains. Our findings reveal an elegant minimal solution for the assembly of monomeric mechano-resistant tethers of variable length.

  13. Coarsening of protein clusters on subcellular drops exhibits strong and sudden size selectivity

    NASA Astrophysics Data System (ADS)

    Brown, Aidan; Rutenberg, Andrew

    2015-03-01

    Autophagy is an important process for the degradation of cellular components, with receptor proteins targeting substrates to downstream autophagy machinery. An important question is how receptor protein interactions lead to their selective accumulation on autophagy substrates. Receptor proteins have recently been observed in clusters, raising the possibility that clustering could affect autophagy selectivity. We investigate the clustering dynamics of the autophagy receptor protein NBR1. In addition to standard receptor protein domains, NBR1 has a ``J'' domain that anchors it to membranes, and a coiled-coil domain that enhances self-interaction. We model coarsening clusters of NBR1 on the surfaces of a polydisperse collection of drops, representing organelles. Despite the disconnected nature of the drop surfaces, we recover dynamical scaling of cluster sizes. Significantly, we find that at a well-defined time after coarsening begins, clusters evaporate from smaller drops and grow on larger drops. Thus, coarsening-driven size selection will localize protein clusters to larger substrates, leaving smaller substrates without clusters. This provides a possible physical mechanism for autophagy selectivity, and can explain reports of size selection during peroxisome degradation.

  14. New Method for Measuring the Anchoring Energy of Strongly-Bound Membrane-Associated Proteins [Method for measuring the anchoring energy of strongly-bound membrane-associated proteins].

    DOE PAGES

    Kent, Michael S.; La Bauve, Elisa; Vernon, Briana C.; ...

    2016-02-01

    Here, we describe a new method to measure the activation energy required to remove a strongly-bound membrane-associated protein from a lipid membrane (anchoring energy). It is based on measuring the rate of release of a liposome-bound protein during centrifugation on a sucrose gradient as a function of time and temperature. The method was used to determine anchoring energy for the soluble dengue virus envelope protein (sE) strongly bound to 80:20 POPC:POPG liposomes at pH 5.5. We also measured the binding energy of sE at the same pH for the initial, predominantly reversible, phase of binding to a 70:30 PC:PG lipidmore » bilayer. The anchoring energy (37 +/- 1.7 kcal/mol, 20% PG) was found to be much larger than the binding energy (7.8 +/- 0.3 kcal/mol for 30% PG, or est. 7.0 kcal/mol for 20% PG). This is consistent with data showing that free sE is a monomer at pH 5.5, but assembles into trimers after associating with membranes. But, trimerization alone is insufficient to account for the observed difference in energies, and we conclude that some energy dissipation occurs during the release process. This new method to determine anchoring energy should be useful to understand the complex interactions of integral monotopic proteins and strongly-bound peripheral membrane proteins with lipid membranes.« less

  15. Synthetic lung surfactants containing SP-B and SP-C peptides plus novel phospholipase-resistant lipids or glycerophospholipids

    PubMed Central

    Notter, Robert H.; Gupta, Rohun; Schwan, Adrian L.; Wang, Zhengdong; Shkoor, Mohanad Gh

    2016-01-01

    Background This study examines the biophysical and preclinical pulmonary activity of synthetic lung surfactants containing novel phospholipase-resistant phosphonolipids or synthetic glycerophospholipids combined with Super Mini-B (S-MB) DATK and/or SP-Css ion-lock 1 peptides that replicate the functional biophysics of surfactant proteins (SP)-B and SP-C. Phospholipase-resistant phosphonolipids used in synthetic surfactants are DEPN-8 and PG-1, molecular analogs of dipalmitoyl phosphatidylcholine (DPPC) and palmitoyl-oleoyl phosphatidylglycerol (POPG), while glycerophospholipids used are active lipid components of native surfactant (DPPC:POPC:POPG 5:3:2 by weight). The objective of the work is to test whether these novel lipid/peptide synthetic surfactants have favorable preclinical activity (biophysical, pulmonary) for therapeutic use in reversing surfactant deficiency or dysfunction in lung disease or injury. Methods Surface activity of synthetic lipid/peptide surfactants was assessed in vitro at 37 °C by measuring adsorption in a stirred subphase apparatus and dynamic surface tension lowering in pulsating and captive bubble surfactometers. Shear viscosity was measured as a function of shear rate on a Wells-Brookfield micro-viscometer. In vivo pulmonary activity was determined by measuring lung function (arterial oxygenation, dynamic lung compliance) in ventilated rats and rabbits with surfactant deficiency/dysfunction induced by saline lavage to lower arterial PO2 to <100 mmHg, consistent with clinical acute respiratory distress syndrome (ARDS). Results Synthetic surfactants containing 5:3:2 DPPC:POPC:POPG or 9:1 DEPN-8:PG-1 combined with 3% (by wt) of S-MB DATK, 3% SP-Css ion-lock 1, or 1.5% each of both peptides all adsorbed rapidly to low equilibrium surface tensions and also reduced surface tension to ≤1 mN/m under dynamic compression at 37 °C. However, dual-peptide surfactants containing 1.5% S-MB DATK + 1.5% SP-Css ion-lock 1 combined with 9:1 DEPN-8

  16. Force sensing by the vascular protein von Willebrand factor is tuned by a strong intermonomer interaction

    PubMed Central

    Müller, Jochen P.; Mielke, Salomé; Löf, Achim; Obser, Tobias; Beer, Christof; Bruetzel, Linda K.; Pippig, Diana A.; Vanderlinden, Willem; Lipfert, Jan; Schneppenheim, Reinhard; Benoit, Martin

    2016-01-01

    The large plasma glycoprotein von Willebrand factor (VWF) senses hydrodynamic forces in the bloodstream and responds to elevated forces with abrupt elongation, thereby increasing its adhesiveness to platelets and collagen. Remarkably, forces on VWF are elevated at sites of vascular injury, where VWF’s hemostatic potential is important to mediate platelet aggregation and to recruit platelets to the subendothelial layer. Adversely, elevated forces in stenosed vessels lead to an increased risk of VWF-mediated thrombosis. To dissect the remarkable force-sensing ability of VWF, we have performed atomic force microscopy (AFM)-based single-molecule force measurements on dimers, the smallest repeating subunits of VWF multimers. We have identified a strong intermonomer interaction that involves the D4 domain and critically depends on the presence of divalent ions, consistent with results from small-angle X-ray scattering (SAXS). Dissociation of this strong interaction occurred at forces above ∼50 pN and provided ∼80 nm of additional length to the elongation of dimers. Corroborated by the static conformation of VWF, visualized by AFM imaging, we estimate that in VWF multimers approximately one-half of the constituent dimers are firmly closed via the strong intermonomer interaction. As firmly closed dimers markedly shorten VWF’s effective length contributing to force sensing, they can be expected to tune VWF’s sensitivity to hydrodynamic flow in the blood and to thereby significantly affect VWF’s function in hemostasis and thrombosis. PMID:26787887

  17. Native-sized recombinant spider silk protein produced in metabolically engineered Escherichia coli results in a strong fiber

    PubMed Central

    Xia, Xiao-Xia; Qian, Zhi-Gang; Ki, Chang Seok; Park, Young Hwan; Kaplan, David L.; Lee, Sang Yup

    2010-01-01

    Spider dragline silk is a remarkably strong fiber that makes it attractive for numerous applications. Much has thus been done to make similar fibers by biomimic spinning of recombinant dragline silk proteins. However, success is limited in part due to the inability to successfully express native-sized recombinant silk proteins (250–320 kDa). Here we show that a 284.9 kDa recombinant protein of the spider Nephila clavipes is produced and spun into a fiber displaying mechanical properties comparable to those of the native silk. The native-sized protein, predominantly rich in glycine (44.9%), was favorably expressed in metabolically engineered Escherichia coli within which the glycyl-tRNA pool was elevated. We also found that the recombinant proteins of lower molecular weight versions yielded inferior fiber properties. The results provide insight into evolution of silk protein size related to mechanical performance, and also clarify why spinning lower molecular weight proteins does not recapitulate the properties of native fibers. Furthermore, the silk expression, purification, and spinning platform established here should be useful for sustainable production of natural quality dragline silk, potentially enabling broader applications. PMID:20660779

  18. Enhancement of protein production via the strong DIT1 terminator and two RNA-binding proteins in Saccharomyces cerevisiae

    PubMed Central

    Ito, Yoichiro; Kitagawa, Takao; Yamanishi, Mamoru; Katahira, Satoshi; Izawa, Shingo; Irie, Kenji; Furutani-Seiki, Makoto; Matsuyama, Takashi

    2016-01-01

    Post-transcriptional upregulation is an effective way to increase the expression of transgenes and thus maximize the yields of target chemicals from metabolically engineered organisms. Refractory elements in the 3′ untranslated region (UTR) that increase mRNA half-life might be available. In Saccharomyces cerevisiae, several terminator regions have shown activity in increasing the production of proteins by upstream coding genes; among these terminators the DIT1 terminator has the highest activity. Here, we found in Saccharomyces cerevisiae that two resident trans-acting RNA-binding proteins (Nab6p and Pap1p) enhance the activity of the DIT1 terminator through the cis element GUUCG/U within the 3′-UTR. These two RNA-binding proteins could upregulate a battery of cell-wall–related genes. Mutagenesis of the DIT1 terminator improved its activity by a maximum of 500% of that of the standard PGK1 terminator. Further understanding and improvement of this system will facilitate inexpensive and stable production of complicated organism-derived drugs worldwide. PMID:27845367

  19. Enhancement of protein production via the strong DIT1 terminator and two RNA-binding proteins in Saccharomyces cerevisiae.

    PubMed

    Ito, Yoichiro; Kitagawa, Takao; Yamanishi, Mamoru; Katahira, Satoshi; Izawa, Shingo; Irie, Kenji; Furutani-Seiki, Makoto; Matsuyama, Takashi

    2016-11-15

    Post-transcriptional upregulation is an effective way to increase the expression of transgenes and thus maximize the yields of target chemicals from metabolically engineered organisms. Refractory elements in the 3' untranslated region (UTR) that increase mRNA half-life might be available. In Saccharomyces cerevisiae, several terminator regions have shown activity in increasing the production of proteins by upstream coding genes; among these terminators the DIT1 terminator has the highest activity. Here, we found in Saccharomyces cerevisiae that two resident trans-acting RNA-binding proteins (Nab6p and Pap1p) enhance the activity of the DIT1 terminator through the cis element GUUCG/U within the 3'-UTR. These two RNA-binding proteins could upregulate a battery of cell-wall-related genes. Mutagenesis of the DIT1 terminator improved its activity by a maximum of 500% of that of the standard PGK1 terminator. Further understanding and improvement of this system will facilitate inexpensive and stable production of complicated organism-derived drugs worldwide.

  20. Strong seed-specific protein expression from the Vigna radiata storage protein 8SGα promoter in transgenic Arabidopsis seeds.

    PubMed

    Chen, Mo-Xian; Zheng, Shu-Xiao; Yang, Yue-Ning; Xu, Chao; Liu, Jie-Sheng; Yang, Wei-Dong; Chye, Mee-Len; Li, Hong-Ye

    2014-03-20

    Vigna radiata (mung bean) is an important crop plant and is a major protein source in developing countries. Mung bean 8S globulins constitute nearly 90% of total seed storage protein and consist of three subunits designated as 8SGα, 8SGα' and 8SGβ. The 5'-flanking sequences of 8SGα' has been reported to confer high expression in transgenic Arabidopsis seeds. In this study, a 472-bp 5'-flanking sequence of 8SGα was identified by genome walking. Computational analysis subsequently revealed the presence of numerous putative seed-specific cis-elements within. The 8SGα promoter was then fused to the gene encoding β-glucuronidase (GUS) to create a reporter construct for Arabidopsis thaliana transformation. The spatial and temporal expression of 8SGα∷GUS, as investigated using GUS histochemical assays, showed GUS expression exclusively in transgenic Arabidopsis seeds. Quantitative GUS assays revealed that the 8SGα promoter showed 2- to 4-fold higher activity than the Cauliflower Mosaic Virus (CaMV) 35S promoter. This study has identified a seed-specific promoter of high promoter strength, which is potentially useful for directing foreign protein expression in seed bioreactors.

  1. MAP5: a novel brain microtubule-associated protein under strong developmental regulation.

    PubMed

    Riederer, B; Cohen, R; Matus, A

    1986-12-01

    A novel microtubule-associated protein, MAP5, is described, whose chemical properties and cytological distribution distinguish it from other known microtubule-associated proteins (MAPs). Its status as a MAP is indicated by the observations that (i) it co-assembles efficiently with microtubules in vitro, (ii) it is localized on microtubules in brain sections by immunogold staining with monoclonal antibody against MAP5 and (iii) immunoaffinity purified MAP5 stimulates tubulin polymerization. Immunoperoxidase staining of brain sections showed that MAP5 is present in neurons throughout the brain and that in them it is evenly distributed throughout axons, dendrites and cell bodies. In this respect it differs from previously described MAPs (1, 2, 3 and tau) which are differentially compartmentalized in brain neurons. MAP5 is not present in axon terminals, dendritic spines or other synaptic elements. It is present at substantially higher levels in neonatal brain than adult and it is more abundant than either MAP1 or MAP2a up to postnatal day 10. The fall in amount of MAP5, from juvenile to adult levels, is completed between postnatal days 10 and 20. This suggests that MAP5 is particularly important in modulating microtubule function during the formation of neuronal processes.

  2. Open reading frame UL26 of human cytomegalovirus encodes a novel tegument protein that contains a strong transcriptional activation domain.

    PubMed

    Stamminger, Thomas; Gstaiger, Matthias; Weinzierl, Konstanze; Lorz, Kerstin; Winkler, Michael; Schaffner, Walter

    2002-05-01

    A selection strategy, the activator trap, was used in order to identify genes of human cytomegalovirus (HCMV) that encode strong transcriptional activation domains in mammalian cells. This approach is based on the isolation of activation domains from a GAL4 fusion library by means of selective plasmid replication, which is mediated in transfected cells by a GAL4-inducible T antigen gene. With this screening strategy, we were able to isolate two types of plasmids encoding transactivating fusion proteins from a library of random HCMV DNA inserts. One plasmid contained the exon 3 of the HCMV IE-1/2 gene region, which has previously been identified as a strong transcriptional activation domain. In the second type of plasmid, the open reading frame (ORF) UL26 of HCMV was fused to the GAL4 DNA-binding domain. By quantitative RNA mapping using S1 nuclease analysis, we were able to classify UL26 as a strong enhancer-type activation domain with no apparent homology to characterized transcriptional activators. Western blot analysis with a specific polyclonal antibody raised against a prokaryotic UL26 fusion protein revealed that two protein isoforms of 21 and 27 kDa are derived from the UL26 ORF in both infected and transfected cells. Both protein isoforms, which arise via alternative usage of two in-frame translational start codons, showed a nuclear localization and could be detected as early as 6 h after infection of primary human fibroblasts. By performing Western blot analysis with purified virions combined with fractionation experiments, we provide evidence that pUL26 is a novel tegument protein of HCMV that is imported during viral infection. Furthermore, we observed transactivation of the HCMV major immediate-early enhancer-promoter by pUL26, whereas several early and late promoters were not affected. Our data suggest that pUL26 is a novel tegument protein of HCMV with a strong transcriptional activation domain that could play an important role during initiation of

  3. Protein domains correlate strongly with exons in multiple eukaryotic genomes--evidence of exon shuffling?

    PubMed

    Liu, Mingyi; Grigoriev, Andrei

    2004-09-01

    We conducted a multi-genome analysis correlating protein domain organization with the exon-intron structure of genes in nine eukaryotic genomes. We observed a significant correlation between the borders of exons and domains on a genomic scale for both invertebrates and vertebrates. In addition, we found that the more complex organisms displayed consistently stronger exon-domain correlation, with substantially more significant correlations detected in vertebrates compared with invertebrates. Our observations concur with the principles of exon shuffling theory, including the prediction of predominantly symmetric phase of introns flanking the borders of correlating exons. These results suggest that extensive exon shuffling events during evolution significantly contributed to the shaping of eukaryotic proteomes.

  4. Bone morphogenetic protein-4 strongly potentiates growth factor-induced proliferation of mammary epithelial cells

    SciTech Connect

    Montesano, Roberto Sarkoezi, Rita; Schramek, Herbert

    2008-09-12

    Bone morphogenetic proteins (BMPs) are multifunctional cytokines that elicit pleiotropic effects on biological processes such as cell proliferation, cell differentiation and tissue morphogenesis. With respect to cell proliferation, BMPs can exert either mitogenic or anti-mitogenic activities, depending on the target cells and their context. Here, we report that in low-density cultures of immortalized mammary epithelial cells, BMP-4 did not stimulate cell proliferation by itself. However, when added in combination with suboptimal concentrations of fibroblast growth factor (FGF)-2, FGF-7, FGF-10, epidermal growth factor (EGF) or hepatocyte growth factor (HGF), BMP-4 potently enhanced growth factor-induced cell proliferation. These results reveal a hitherto unsuspected interplay between BMP-4 and growth factors in the regulation of mammary epithelial cell proliferation. We suggest that the ability of BMP-4 to potentiate the mitogenic activity of multiple growth factors may contribute to mammary gland ductal morphogenesis as well as to breast cancer progression.

  5. Preclinical evaluation of bacterially produced RSV-G protein vaccine: Strong protection against RSV challenge in cotton rat model

    PubMed Central

    Fuentes, Sandra; Klenow, Laura; Golding, Hana; Khurana, Surender

    2017-01-01

    In current study, we evaluated the safety and protective efficacy of recombinant unglycosylated RSV G protein ectodomain produced in E. coli (in presence and absence of oil-in-water adjuvant) in a preclinical RSV susceptible cotton rat challenge model compared to formaldehyde inactivated RSV (FI-RSV) and live RSV experimental infection. The adjuvanted G protein vaccine induced robust neutralization antibody responses comparable to those generated by live RSV infection. Importantly, adjuvanted G protein significantly reduced viral loads in both the lungs and nose at early time points following viral challenge. Antibody kinetics determined by Surface Plasmon Resonance showed that adjuvanted G generated 10-fold higher G-binding antibodies compared to non-adjvuanted G vaccine and live RSV infection, which correlated strongly with both neutralization titers and viral load titers in the nose and lungs post-viral challenge. Antibody diversity analysis revealed immunodominant antigenic sites in the N- and C-termini of the RSV-G protein, that were boosted >10-fold by adjuvant and inversely correlated with viral load titers. Enhanced lung pathology was observed only in animals vaccinated with FI-RSV, but not in animals vaccinated with unadjuvanted or adjuvanted RSV-G vaccine after viral challenge. The bacterially produced unglycosylated G protein could be developed as a protective vaccine against RSV disease. PMID:28186208

  6. Preparation of a novel dual-function strong cation exchange/hydrophobic interaction chromatography stationary phase for protein separation.

    PubMed

    Zhao, Kailou; Yang, Li; Wang, Xuejiao; Bai, Quan; Yang, Fan; Wang, Fei

    2012-08-30

    We have explored a novel dual-function stationary phase which combines both strong cation exchange (SCX) and hydrophobic interaction chromatography (HIC) characteristics. The novel dual-function stationary phase is based on porous and spherical silica gel functionalized with ligand containing sulfonic and benzyl groups capable of electrostatic and hydrophobic interaction functionalities, which displays HIC character in a high salt concentration, and IEC character in a low salt concentration in mobile phase employed. As a result, it can be employed to separate proteins with SCX and HIC modes, respectively. The resolution and selectivity of the dual-function stationary phase were evaluated under both HIC and SCX modes with standard proteins and can be comparable to that of conventional IEC and HIC columns. More than 96% of mass and bioactivity recoveries of proteins can be achieved in both HIC and SCX modes, respectively. The results indicated that the novel dual-function column could replace two individual SCX and HIC columns for protein separation. Mixed retention mechanism of proteins on this dual-function column based on stoichiometric displacement theory (SDT) in LC was investigated to find the optimal balance of the magnitude of electrostatic and hydrophobic interactions between protein and the ligand on the silica surface in order to obtain high resolution and selectivity for protein separation. In addition, the effects of the hydrophobicity of the ligand of the dual-function packings and pH of the mobile phase used on protein separation were also investigated in detail. The results show that the ligand with suitable hydrophobicity to match the electrostatic interaction is very important to prepare the dual-function stationary phase, and a better resolution and selectivity can be obtained at pH 6.5 in SCX mode. Therefore, the dual-function column can replace two individual SCX and HIC columns for protein separation and be used to set up two-dimensional liquid

  7. Structural Ensembles of Intrinsically Disordered Proteins Depend Strongly on Force Field: A Comparison to Experiment.

    PubMed

    Rauscher, Sarah; Gapsys, Vytautas; Gajda, Michal J; Zweckstetter, Markus; de Groot, Bert L; Grubmüller, Helmut

    2015-11-10

    Intrinsically disordered proteins (IDPs) are notoriously challenging to study both experimentally and computationally. The structure of IDPs cannot be described by a single conformation but must instead be described as an ensemble of interconverting conformations. Atomistic simulations are increasingly used to obtain such IDP conformational ensembles. Here, we have compared the IDP ensembles generated by eight all-atom empirical force fields against primary small-angle X-ray scattering (SAXS) and NMR data. Ensembles obtained with different force fields exhibit marked differences in chain dimensions, hydrogen bonding, and secondary structure content. These differences are unexpectedly large: changing the force field is found to have a stronger effect on secondary structure content than changing the entire peptide sequence. The CHARMM 22* ensemble performs best in this force field comparison: it has the lowest error in chemical shifts and J-couplings and agrees well with the SAXS data. A high population of left-handed α-helix is present in the CHARMM 36 ensemble, which is inconsistent with measured scalar couplings. To eliminate inadequate sampling as a reason for differences between force fields, extensive simulations were carried out (0.964 ms in total); the remaining small sampling uncertainty is shown to be much smaller than the observed differences. Our findings highlight how IDPs, with their rugged energy landscapes, are highly sensitive test systems that are capable of revealing force field deficiencies and, therefore, contributing to force field development.

  8. Strong morphological defects in conditional Arabidopsis abp1 knock-down mutants generated in absence of functional ABP1 protein

    PubMed Central

    Perrot-Rechenmann, Catherine; Friml, Jiří

    2016-01-01

    The Auxin Binding Protein 1 (ABP1) is one of the most studied proteins in plants. Since decades ago, it has been the prime receptor candidate for the plant hormone auxin with a plethora of described functions in auxin signaling and development. The developmental importance of ABP1 has recently been questioned by identification of Arabidopsis thaliana abp1 knock-out alleles that show no obvious phenotypes under normal growth conditions. In this study, we examined the contradiction between the normal growth and development of the abp1 knock-outs and the strong morphological defects observed in three different ethanol-inducible abp1 knock-down mutants ( abp1-AS, SS12K, SS12S). By analyzing segregating populations of abp1 knock-out vs. abp1 knock-down crosses we show that the strong morphological defects that were believed to be the result of conditional down-regulation of ABP1 can be reproduced also in the absence of the functional ABP1 protein. This data suggests that the phenotypes in  abp1 knock-down lines are due to the off-target effects and asks for further reflections on the biological function of ABP1 or alternative explanations for the missing phenotypic defects in the abp1 loss-of-function alleles. PMID:26925228

  9. Achieving efficient protein expression in Trichoderma reesei by using strong constitutive promoters

    PubMed Central

    2012-01-01

    Backgrounds The fungus Trichoderma reesei is an important workhorse for expression of homologous or heterologous genes, and the inducible cbh1 promoter is generally used. However, constitutive expression is more preferable in some cases than inducible expression that leads to production of unwanted cellulase components. In this work, constitutive promoters of T. reesei were screened and successfully used for high level homologous expression of xylanase II. Results The transcriptional profiles of 13 key genes that participate in glucose metabolism in T. reesei were analyzed by quantitative real-time reverse-transcription polymerase chain reaction (RT-qPCR). The results indicated that the mRNA levels of pdc (encoding pyruvate decarboxylase) and eno (encoding enolase) genes were much higher than other genes under high glucose conditions. Recombinant T. reesei strains that homologously expressed xylanase II were constructed by using the promoters of the pdc and eno genes, and they respectively produced 9266 IU/ml and 8866 IU/ml of xylanase activities in the cultivation supernatant in a medium with high glucose concentration. The productivities of xylanase II were 1.61 g/L (with the pdc promoter) and 1.52 g/L (with the eno promoter), approximately accounted for 83% and 82% of the total protein secreted by T. reesei, respectively. Conclusions This work demonstrates the screening of constitutive promoters by using RT-qPCR in T. reesei, and has obtained the highest expression of recombinant xylanase II to date by using these promoters. PMID:22709462

  10. The Expression of the Zonula Adhaerens Protein PLEKHA7 Is Strongly Decreased in High Grade Ductal and Lobular Breast Carcinomas

    PubMed Central

    Tille, Jean-Christophe; Ho, Liza; Shah, Jimit; Seyde, Olivia; McKee, Thomas A.; Citi, Sandra

    2015-01-01

    PLEKHA7 is a junctional protein, which participates in a complex that stabilizes E-cadherin at the zonula adhaerens. Since E-cadherin is involved in epithelial morphogenesis, signaling, and tumor progression, we explored PLEKHA7 expression in cancer. PLEKHA7 expression was assessed in invasive ductal and lobular carcinomas of the breast by immunohistochemistry, immunofluorescence and quantitative RT-PCR. PLEKHA7 was detected at epithelial junctions of normal mammary ducts and lobules, and of tubular and micropapillary structures within G1 and G2 ductal carcinomas. At these junctions, the localization of PLEKHA7 was along the circumferential belt (zonula adhaerens), and only partially overlapping with that of E-cadherin, p120ctn and ZO-1, as shown previously in rodent tissues. PLEKHA7 immunolabeling was strongly decreased in G3 ductal carcinomas and undetectable in lobular carcinomas. PLEKHA7 mRNA was detected in both ductal and lobular carcinomas, with no observed correlation between mRNA levels and tumor type or grade. In summary, PLEKHA7 is a junctional marker of epithelial cells within tubular structures both in normal breast tissue and ductal carcinomas, and since PLEKHA7 protein but not mRNA expression is strongly decreased or lost in high grade ductal carcinomas and in lobular carcinomas, loss of PLEKHA7 is a newly characterized feature of these carcinomas. PMID:26270346

  11. Polymer monoliths with low hydrophobicity for strong cation-exchange capillary liquid chromatography of peptides and proteins.

    PubMed

    Gu, Binghe; Li, Yun; Lee, Milton L

    2007-08-01

    Two polymer monoliths were designed and synthesized from commercially available monomers with an attempt to decrease hydrophobicity for strong cation-exchange chromatography. One was prepared from the copolymerization of sulfoethyl methacrylate and poly(ethylene glycol) diacrylate, and the other was synthesized from vinylsulfonic acid and poly(ethylene glycol) diacrylate. Both of the monoliths were synthesized inside 75-microm i.d., UV-transparent fused-silica capillaries by photopolymerization. The hydrophobicities of the two monoliths were systematically evaluated using standard synthetic undecapeptides under ion-exchange conditions and propyl paraben under reversed-phase conditions. The poly(sulfoethyl methacrylate) monolith demonstrated similar hydrophobicity as a monolith prepared from copolymerization of 2-acrylamido-2-methyl-1-propanesulfonic acid and poly(ethylene glycol) diacrylate, and 40% acetonitrile was required to suppress any hydrophobic interactions with peptides under ion-exchange conditions. However, with the use of vinylsulfonic acid as the functional monomer, a monolith with very low hydrophobicity was obtained, making it suitable for strong cation-exchange liquid chromatography of both peptides and proteins. It was found that monolith hydrophobicity could be adjusted by selection of monomers that differ in hydrocarbon content and type of vinyl group. Finally, excellent separations of model protein standards and high-density lipoproteins were achieved using the poly(vinylsulfonic acid) monolith. Five subclasses of high-density lipoproteins were resolved using a simple linear NaCl gradient.

  12. Dengue E Protein Domain III-Based DNA Immunisation Induces Strong Antibody Responses to All Four Viral Serotypes

    PubMed Central

    Chan, Kuan Rong; Tan, Hwee Cheng; Bestagno, Marco; Ooi, Eng Eong; Burrone, Oscar R.

    2015-01-01

    Dengue virus (DENV) infection is a major emerging disease widely distributed throughout the tropical and subtropical regions of the world affecting several millions of people. Despite constants efforts, no specific treatment or effective vaccine is yet available. Here we show a novel design of a DNA immunisation strategy that resulted in the induction of strong antibody responses with high neutralisation titres in mice against all four viral serotypes. The immunogenic molecule is an engineered version of the domain III (DIII) of the virus E protein fused to the dimerising CH3 domain of the IgG immunoglobulin H chain. The DIII sequences were also codon-optimised for expression in mammalian cells. While DIII alone is very poorly secreted, the codon-optimised fusion protein is rightly expressed, folded and secreted at high levels, thus inducing strong antibody responses. Mice were immunised using gene-gun technology, an efficient way of intradermal delivery of the plasmid DNA, and the vaccine was able to induce neutralising titres against all serotypes. Additionally, all sera showed reactivity to a recombinant DIII version and the recombinant E protein produced and secreted from mammalian cells in a mono-biotinylated form when tested in a conformational ELISA. Sera were also highly reactive to infective viral particles in a virus-capture ELISA and specific for each serotype as revealed by the low cross-reactive and cross-neutralising activities. The serotype specific sera did not induce antibody dependent enhancement of infection (ADE) in non-homologous virus serotypes. A tetravalent immunisation protocol in mice showed induction of neutralising antibodies against all four dengue serotypes as well. PMID:26218926

  13. Natural Anti-Infective Pulmonary Proteins: In Vivo Cooperative Action of Surfactant Protein SP-A and the Lung Antimicrobial Peptide SP-BN.

    PubMed

    Coya, Juan Manuel; Akinbi, Henry T; Sáenz, Alejandra; Yang, Li; Weaver, Timothy E; Casals, Cristina

    2015-08-15

    The anionic antimicrobial peptide SP-B(N), derived from the N-terminal saposin-like domain of the surfactant protein (SP)-B proprotein, and SP-A are lung anti-infective proteins. SP-A-deficient mice are more susceptible than wild-type mice to lung infections, and bacterial killing is enhanced in transgenic mice overexpressing SP-B(N). Despite their potential anti-infective action, in vitro studies indicate that several microorganisms are resistant to SP-A and SP-B(N). In this study, we test the hypothesis that these proteins act synergistically or cooperatively to strengthen each other's microbicidal activity. The results indicate that the proteins acted synergistically in vitro against SP-A- and SP-B(N)-resistant capsulated Klebsiella pneumoniae (serotype K2) at neutral pH. SP-A and SP-B(N) were able to interact in solution (Kd = 0.4 μM), which enabled their binding to bacteria with which SP-A or SP-B(N) alone could not interact. In vivo, we found that treatment of K. pneumoniae-infected mice with SP-A and SP-B(N) conferred more protection against K. pneumoniae infection than each protein individually. SP-A/SP-B(N)-treated infected mice showed significant reduction of bacterial burden, enhanced neutrophil recruitment, and ameliorated lung histopathology with respect to untreated infected mice. In addition, the concentrations of inflammatory mediators in lung homogenates increased early in infection in contrast with the weak inflammatory response of untreated K. pneumoniae-infected mice. Finally, we found that therapeutic treatment with SP-A and SP-B(N) 6 or 24 h after bacterial challenge conferred significant protection against K. pneumoniae infection. These studies show novel anti-infective pathways that could drive development of new strategies against pulmonary infections.

  14. Dimethyl Disulfide Produced by the Naturally Associated Bacterium Bacillus sp B55 Promotes Nicotiana attenuata Growth by Enhancing Sulfur Nutrition[W

    PubMed Central

    Meldau, Dorothea G.; Meldau, Stefan; Hoang, Long H.; Underberg, Stefanie; Wünsche, Hendrik; Baldwin, Ian T.

    2013-01-01

    Bacillus sp B55, a bacterium naturally associated with Nicotiana attenuata roots, promotes growth and survival of wild-type and, particularly, ethylene (ET)–insensitive 35S-ethylene response1 (etr1) N. attenuata plants, which heterologously express the mutant Arabidopsis thaliana receptor ETR1-1. We found that the volatile organic compound (VOC) blend emitted by B55 promotes seedling growth, which is dominated by the S-containing compound dimethyl disulfide (DMDS). DMDS was depleted from the headspace during cocultivation with seedlings in bipartite Petri dishes, and 35S was assimilated from the bacterial VOC bouquet and incorporated into plant proteins. In wild-type and 35S-etr1 seedlings grown under different sulfate (SO4−2) supply conditions, exposure to synthetic DMDS led to genotype-dependent plant growth promotion effects. For the wild type, only S-starved seedlings benefited from DMDS exposure. By contrast, growth of 35S-etr1 seedlings, which we demonstrate to have an unregulated S metabolism, increased at all SO4−2 supply rates. Exposure to B55 VOCs and DMDS rescued many of the growth phenotypes exhibited by ET-insensitive plants, including the lack of root hairs, poor lateral root growth, and low chlorophyll content. DMDS supplementation significantly reduced the expression of S assimilation genes, as well as Met biosynthesis and recycling. We conclude that DMDS by B55 production is a plant growth promotion mechanism that likely enhances the availability of reduced S, which is particularly beneficial for wild-type plants growing in S-deficient soils and for 35S-etr1 plants due to their impaired S uptake/assimilation/metabolism. PMID:23903320

  15. No strong association between HER-2/neu protein overexpression and gene amplification in high-grade invasive urothelial carcinomas.

    PubMed

    Caner, Vildan; Turk, Nilay Sen; Duzcan, Fusun; Tufan, N Lale Satiroglu; Kelten, E Canan; Zencir, Sevil; Dodurga, Yavuz; Bagci, Huseyin; Duzcan, S Ender

    2008-09-01

    The generation of urothelial carcinoma is caused by the accumulation of various molecular changes, as in most malignancies. There are conflicting data about the status of HER-2/neu oncogene in urothelial carcinomas. The aim of this study was to determine the status of HER-2/neu oncogene in high-grade invasive urothelial carcinoma of urinary bladder both in protein and DNA level. We evaluated HER-2/neu protein overexpression by immunohistochemistry (IHC) and gene amplification by fluorescent in situ hybridization (FISH) and real-time quantitative PCR in paraffin-embedded samples of high-grade invasive urothelial carcinoma obtained from 36 patients. Polysomy 17 was also assessed by FISH. Immunohistochemically, HER-2/neu protein overexpression was observed in 22 (61.1%) tumors (ten tumors with score 3+ and 12 with score 2+). Fourteen of 36 tumors (38.9%) were evaluated as negative (score 0 or 1+). Complete concordance between FISH and the PCR was seen in all of the samples scored as 0 and 1+ by IHC. HER-2/neu gene amplification was observed in three of 27 (11.1%) tumors by FISH (nine samples were non-informative) and in eight of 36 (22.2%) tumors by the PCR. The complete concordance between HER2-2/neu protein overexpression and gene amplification was seen only in three of 27 tumors. Polysomy 17 was seen in nine tumors (33.3%). The results indicated that, in contrast to breast cancer, there was no strong association between HER-2/neu overexpression and gene amplification in invasive urothelial carcinomas, and polysomy 17 was higher in tumors showing HER-2/neu overexpression.

  16. Strong stimulation of recombinant protein production in Escherichia coli by combining stimulatory control elements in an expression cassette

    PubMed Central

    2012-01-01

    Background The XylS/Pm expression system has been used to produce recombinant proteins at industrial levels in Escherichia coli. Activation of transcription from the Pm promoter takes place in the presence of benzoic acid or derivatives of it. Previous mutagenesis studies resulted in identification of several variants of the expression control elements xylS (X), Pm (P) and the 5'-untranslated region (U) that individually gave rise to strongly stimulated expression. The goal of this study was to test if combination of such stimulatory mutations in the same expression vectors would lead to further increase of expression levels. Results We combined X, P and U variants that were originally identified due to their ability to strongly stimulate expression of the reporter gene bla (resistance to penicillin). Combination of optimized elements stimulated bla expression up to 75-fold (X, P and U combined) relative to the wild-type system, while accumulated transcript levels increased about 50-fold. This is much more than for the elements individually. We also tested combination of the variant elements on two other and unrelated genes, celB (encoding phosphoglucomutase) and the human growth factor gene gm-csf. Protein production from these genes is much more efficient than from bla in the wild-type system, but expression was still significantly stimulated by the combination of X, P and U variants, although not to the same extent as for bla. We also integrated a single copy of the expression cassette with each gene into the E. coli chromosome and found that the expression level from this single copy was higher for bla than for the wild-type plasmid system, while it was lower for celB and gm-csf. Conclusion Our results show that combination of stimulatory expression control elements can be used to further increase production of different proteins in E. coli. For one reporter gene (bla) this allowed for more protein production from a single gene copy integrated on the chromosome

  17. Draft Genome Sequence of the Fungus Paraphoma sp. B47-9, a Producer of a Biodegradable Plastic–Degrading Enzyme

    PubMed Central

    Sameshima-Yamashita, Yuka; Koike, Hideaki; Koitabashi, Motoo; Saika, Azusa; Morita, Tomotake; Yarimizu, Tohru

    2016-01-01

    Paraphoma sp. B47-9 is a producer of a biodegradable plastic–degrading enzyme. Here, we report the draft genome sequence of this strain. The draft genome assembly has a size of 39.3 Mb with a GC content of 52.4% and consists of 185 scaffolds. PMID:27795277

  18. Draft Genome Sequence of the Fungus Paraphoma sp. B47-9, a Producer of a Biodegradable Plastic-Degrading Enzyme.

    PubMed

    Sameshima-Yamashita, Yuka; Koike, Hideaki; Koitabashi, Motoo; Saika, Azusa; Morita, Tomotake; Yarimizu, Tohru; Kitamoto, Hiroko

    2016-10-20

    Paraphoma sp. B47-9 is a producer of a biodegradable plastic-degrading enzyme. Here, we report the draft genome sequence of this strain. The draft genome assembly has a size of 39.3 Mb with a GC content of 52.4% and consists of 185 scaffolds.

  19. Elongation Factor Tu and Heat Shock Protein 70 Are Membrane-Associated Proteins from Mycoplasma ovipneumoniae Capable of Inducing Strong Immune Response in Mice

    PubMed Central

    Jiang, Fei; He, Jinyan; Navarro-Alvarez, Nalu; Xu, Jian; Li, Xia; Li, Peng; Wu, Wenxue

    2016-01-01

    Chronic non-progressive pneumonia, a disease that has become a worldwide epidemic has caused considerable loss to sheep industry. Mycoplasma ovipneumoniae (M. ovipneumoniae) is the causative agent of interstitial pneumonia in sheep, goat and bighorn. We here have identified by immunogold and immunoblotting that elongation factor Tu (EF-Tu) and heat shock protein 70 (HSP 70) are membrane-associated proteins on M. ovipneumonaiea. We have evaluated the humoral and cellular immune responses in vivo by immunizing BALB/c mice with both purified recombinant proteins rEF-Tu and rHSP70. The sera of both rEF-Tu and rHSP70 treated BALB/c mice demonstrated increased levels of IgG, IFN-γ, TNF-α, IL-12(p70), IL-4, IL-5 and IL-6. In addition, ELISPOT assay showed significant increase in IFN-γ+ secreting lymphocytes in the rHSP70 group when compared to other groups. Collectively our study reveals that rHSP70 induces a significantly better cellular immune response in mice, and may act as a Th1 cytokine-like adjuvant in immune response induction. Finally, growth inhibition test (GIT) of M. ovipneumoniae strain Y98 showed that sera from rHSP70 or rEF-Tu-immunized mice inhibited in vitro growth of M. ovipneumoniae. Our data strongly suggest that EF-Tu and HSP70 of M. ovipneumoniae are membrane-associated proteins capable of inducing antibody production, and cytokine secretion. Therefore, these two proteins may be potential candidates for vaccine development against M. ovipneumoniae infection in sheep. PMID:27537186

  20. Elongation Factor Tu and Heat Shock Protein 70 Are Membrane-Associated Proteins from Mycoplasma ovipneumoniae Capable of Inducing Strong Immune Response in Mice.

    PubMed

    Jiang, Fei; He, Jinyan; Navarro-Alvarez, Nalu; Xu, Jian; Li, Xia; Li, Peng; Wu, Wenxue

    2016-01-01

    Chronic non-progressive pneumonia, a disease that has become a worldwide epidemic has caused considerable loss to sheep industry. Mycoplasma ovipneumoniae (M. ovipneumoniae) is the causative agent of interstitial pneumonia in sheep, goat and bighorn. We here have identified by immunogold and immunoblotting that elongation factor Tu (EF-Tu) and heat shock protein 70 (HSP 70) are membrane-associated proteins on M. ovipneumonaiea. We have evaluated the humoral and cellular immune responses in vivo by immunizing BALB/c mice with both purified recombinant proteins rEF-Tu and rHSP70. The sera of both rEF-Tu and rHSP70 treated BALB/c mice demonstrated increased levels of IgG, IFN-γ, TNF-α, IL-12(p70), IL-4, IL-5 and IL-6. In addition, ELISPOT assay showed significant increase in IFN-γ+ secreting lymphocytes in the rHSP70 group when compared to other groups. Collectively our study reveals that rHSP70 induces a significantly better cellular immune response in mice, and may act as a Th1 cytokine-like adjuvant in immune response induction. Finally, growth inhibition test (GIT) of M. ovipneumoniae strain Y98 showed that sera from rHSP70 or rEF-Tu-immunized mice inhibited in vitro growth of M. ovipneumoniae. Our data strongly suggest that EF-Tu and HSP70 of M. ovipneumoniae are membrane-associated proteins capable of inducing antibody production, and cytokine secretion. Therefore, these two proteins may be potential candidates for vaccine development against M. ovipneumoniae infection in sheep.

  1. Oral Combination Vaccine, Comprising Bifidobacterium Displaying Hepatitis C Virus Nonstructural Protein 3 and Interferon-α, Induces Strong Cellular Immunity Specific to Nonstructural Protein 3 in Mice.

    PubMed

    Kitagawa, Koichi; Omoto, Chika; Oda, Tsugumi; Araki, Ayame; Saito, Hiroki; Shigemura, Katsumi; Katayama, Takane; Hotta, Hak; Shirakawa, Toshiro

    2017-01-23

    We previously generated an oral hepatitis C virus (HCV) vaccine using Bifidobacterium displaying the HCV nonstructural protein 3 (NS3) polypeptide. NS3-specific cellular immunity is important for viral clearance and recovery from HCV infection. In this study, we enhanced the cellular immune responses induced by our oral HCV vaccine, Bifidobacterium longum 2165 (B. longum 2165), by combining interferon-α (IFN-α) as an adjuvant with the vaccine in a mouse experimental model. IFN-α is a widely used cytokine meeting the standard of care (SOC) for HCV infection and plays various immunoregulatory roles. We treated C57BL/6N mice with B. longum 2165 every other day and/or IFN-α twice a week for a month and then analyzed the immune responses using spleen cells. We determined the induction of NS3-specific cellular immunity by cytokine quantification, intracellular cytokine staining, and a cytotoxic T lymphocyte (CTL) assay targeting EL4 tumor cells expressing NS3/4A protein (EL4-NS3/4A). We also treated mice bearing EL4-NS3/4A tumor with the combination therapy in vivo. The results confirmed that the combination therapy of B. longum 2165 and IFN-α induced significantly higher IFN-γ secretion, higher population of CD4(+)T and CD8(+)T cells secreting IFN-γ, and higher CTL activity against EL4-NS3/4A cells compared with the control groups of phosphate-buffered saline, B. longum 2165 alone, and IFN-α alone (p < 0.05). We also confirmed that the combination therapy strongly enhanced tumor growth inhibitory effects in vivo with no serious adverse effects (p < 0.05). These results suggest that the combination of B. longum 2165 and IFN-α could induce a strong cellular immunity specific to NS3 protein as a combination therapy augmenting the current SOC immunotherapy against chronic HCV infection.

  2. Cloning, expression and biochemical characterization of a β-carbonic anhydrase from the soil bacterium Enterobacter sp. B13.

    PubMed

    Eminoğlu, Ayşenur; Vullo, Daniela; Aşık, Aycan; Çolak, Dilşat Nigar; Supuran, Claudiu T; Çanakçı, Sabriye; Osman Beldüz, Ali

    2016-12-01

    A recombinant carbonic anhydrase (CA, EC 4.2.1.1) from the soil-dwelling bacterium Enterobacter sp. B13 was cloned and purified by Co(2+) affinity chromatography. Bioinformatic analysis showed that the new enzyme (denominated here B13-CA) belongs to the β-class CAs and to possess 95% homology with the ortholog enzyme from Escherichia coli encoded by the can gene, whereas its sequence homology with the other such enzyme from E. coli (encoded by the cynT gene) was of 33%. B13-CA was characterized kinetically as a catalyst for carbon dioxide hydration to bicarbonate and protons. The enzyme shows a significant catalytic activity, with the following kinetic parameters at 20 °C and pH of 8.3: kcat of 4.8 × 10(5) s(-1) and kcat/Km of 5.6 × 10(7) M(-1) × s(-1). This activity was potently inhibited by acetazolamide which showed a KI of 78.9 nM. Although only this compound was investigated for the moment as B13-CA inhibitor, further studies may reveal new classes of inhibitors/activators of this enzyme which may show biomedical or environmental applications, considering the posssible role of this enzyme in CaCO3 biomineralization processes.

  3. Sulfonamide inhibition studies of the β-carbonic anhydrase from the newly discovered bacterium Enterobacter sp. B13.

    PubMed

    Eminoğlu, Ayşenur; Vullo, Daniela; Aşık, Aycan; Çolak, Dilşat Nigar; Çanakçı, Sabriye; Beldüz, Ali Osman; Supuran, Claudiu T

    2016-04-01

    The genome of the newly identified bacterium Enterobacter sp. B13 encodes for a β-class carbonic anhydrases (CAs, EC 4.2.1.1), EspCA. This enzyme was recently cloned, and characterized kinetically by this group (J. Enzyme Inhib. Med. Chem. 2016, 31). Here we report an inhibition study with sulfonamides and sulfamates of this enzyme. The best EspCA inhibitors were some sulfanylated sulfonamides with elongated molecules, metanilamide, 4-aminoalkyl-benzenesulfonamides, acetazolamide, and deacetylated methazolamide (KIs in the range of 58.7-96.5nM). Clinically used agents such as methazolamide, ethoxzolamide, dorzolamide, brinzolamide, benzolamide, zonisamide, sulthiame, sulpiride, topiramate and valdecoxib were slightly less effective inhibitors (KIs in the range of 103-138nM). Saccharin, celecoxib, dichlorophenamide and many simple benzenesulfonamides were even less effective as EspCA inhibitors, with KIs in the range of 384-938nM. Identification of effective inhibitors of this bacterial enzyme may lead to pharmacological tools useful for understanding the physiological role(s) of the β-class CAs in bacterial pathogenicity/virulence.

  4. SP-B and SP-C Containing New Synthetic Surfactant for Treatment of Extremely Immature Lamb Lung

    PubMed Central

    Sato, Atsuyasu; Ikegami, Machiko

    2012-01-01

    Although superiority of synthetic surfactant over animal-driven surfactant has been known, there is no synthetic surfactant commercially available at present. Many trials have been made to develop synthetic surfactant comparable in function to animal-driven surfactant. The efficacy of treatment with a new synthetic surfactant (CHF5633) containing dipalmitoylphosphatidylcholine, phosphatidylglycerol, SP-B analog, and SP-C analog was evaluated using immature newborn lamb model and compared with animal lung tissue-based surfactant Survanta. Lambs were treated with a clinical dose of 200 mg/kg CHF5633, 100 mg/kg Survanta, or air after 15 min initial ventilation. All the lambs treated with air died of respiratory distress within 90 min of age. During a 5 h study period, Pco2 was maintained at 55 mmHg with 24 cmH2O peak inspiratory pressure for both groups. The preterm newborn lamb lung functions were dramatically improved by CHF5633 treatment. Slight, but significant superiority of CHF5633 over Survanta was demonstrated in tidal volume at 20 min and dynamic lung compliance at 20 and 300 min. The ultrastructure of CHF5633 was large with uniquely aggregated lipid particles. Increased uptake of CHF5633 by alveolar monocytes for catabolism was demonstrated by microphotograph, which might be associated with the higher treatment dose of CHF5633. The higher catabolism of CHF5633 was also suggested by the similar amount of surfactant lipid in bronchoalveolar lavage fluid (BALF) between CHF5633 and Survanta groups, despite the 2-fold higher treatment dose of CHF5633. Under the present ventilation protocol, lung inflammation was minimal for both groups, evaluated by inflammatory cell numbers in BALF and expression of IL-1β, IL-6, IL-8, and TNFα mRNA in the lung tissue. In conclusion, the new synthetic surfactant CHF5633 was effective in treating extremely immature newborn lambs with surfactant deficiency during the 5 h study period. PMID:22808033

  5. High yield expression of an AHL-lactonase from Bacillus sp. B546 in Pichia pastoris and its application to reduce Aeromonas hydrophila mortality in aquaculture

    PubMed Central

    2010-01-01

    Background Aeromonas hydrophila is a serious pathogen and can cause hemorrhagic septicemia in fish. To control this disease, antibiotics and chemicals are widely used which can consequently result in "superbugs" and chemical accumulation in the food chain. Though vaccine against A. hydrophila is available, its use is limited due to multiple serotypes of this pathogen and problems of safety and efficacy. Another problem with vaccination is the ability to apply it to small fish especially in high numbers. In this study, we tried a new way to attenuate the A. hydrophila infection by using a quorum quenching strategy with a recombinant AHL-lactonase expressed in Pichia pastoris. Results The AHL-lactonase (AiiAB546) from Bacillus sp. B546 was produced extracellularly in P. pastoris with a yield of 3,558.4 ± 81.3 U/mL in a 3.7-L fermenter when using 3-oxo-C8-HSL as the substrate. After purification with a HiTrap Q Sepharose column, the recombinant homogenous protein showed a band of 33.6 kDa on SDS-PAGE, higher than the calculated molecular mass (28.14 kDa). Deglycosylation of AiiAB546 with Endo H confirmed the occurrence of N-glycosylation. The purified recombinant AiiAB546 showed optimal activity at pH 8.0 and 20°C, exhibited excellent stability at pH 8.0-12.0 and thermal stability at 70°C, was firstly confirmed to be significantly protease-resistant, and had wide substrate specificity. In application test, when co-injected with A. hydrophila in common carp, recombinant AiiAB546 decreased the mortality rate and delayed the mortality time of fish. Conclusions Our results not only indicate the possibility of mass-production of AHL-lactonase at low cost, but also open up a promising foreground of application of AHL-lactonase in fish to control A. hydrophila disease by regulating its virulence. To our knowledge, this is the first report on heterologous expression of AHL-lactonase in P. pastoris and attenuating A. hydrophila virulence by co-injection with AHL

  6. Strong HER-2/neu protein overexpression by immunohistochemistry often does not predict oncogene amplification by fluorescence in situ hybridization.

    PubMed

    Hammock, Lauren; Lewis, Melinda; Phillips, Carol; Cohen, Cynthia

    2003-10-01

    Breast cancer patients with HER-2/neu oncogene amplification by fluorescence in situ hybridization (FISH) have been shown to have a better response to trastuzumab (Herceptin) therapy than those showing HER-2/neu protein overexpression only. Many centers currently perform FISH only on tumors showing 2+ HER-2/neu positivity by immunohistochemistry (IHC), with the assumption that 3+ positivity virtually equates with amplification. Results of FISH performed on 102 breast cancer cases over a 12-month period were correlated with HER-2/neu IHC results. FISH was performed using a ratio of HER-2/neu and chromosome 17 centromere signal counts (PathVysion; Vysis, Downers Grove, IL). Immunohistochemical expression of HER-2/neu was evaluated according to the published scoring guidelines of the HercepTest (Dako, Carpinteria, CA). Only 22 of 45 tumors with 3+ positivity (49%) showed amplification by FISH. Only 2 of 25 cases with 2+ staining by IHC (6%) showed gene amplification, and 1 of 25 cases with negative IHC staining (4%) showed weak amplification. Of the 25 cases showing oncogene amplification, 22 (88%) showed 3+ IHC positivity, 2 (8%) showed 2+ positivity, and 1 (4%) was negative by IHC. More than 50% of breast tumors showing strong 3+ HER-2/neu staining do not show oncogene amplification by FISH. Most tumors with 2+ and negative IHC also fail to amplify. In our experience, FISH studies should be performed on all 3+ and 2+ staining tumors to avoid inappropriate and toxic treatment. The decision to perform FISH on IHC-negative tumors should be guided by additional parameters, including tumor grade and estrogen receptor status.

  7. Strong associations among rumen endotoxin and acute phase proteins with plasma minerals in lactating cows fed graded amounts of concentrate.

    PubMed

    Zebeli, Q; Dunn, S M; Ametaj, B N

    2010-04-01

    The objective of this investigation was to determine associations among rumen endotoxin, plasma serum amyloid A (SAA), and C-reactive protein (CRP) with plasma Ca, Fe, Zn, and Cu in lactating cows challenged with graded amounts of rolled barley grain in the diet (i.e., 0, 15, 30, and 45% of DMI). Correlative relationships among variables were determined by linear and nonlinear regression procedures adjusted for the effects of day, animal, and experimental period. Increasing the amount of grain in the diet was successful in inducing an acute phase response, as assessed by augmentation of rumen endotoxin and plasma CRP and SAA (P < 0.01). The correlative analysis revealed inverse, nonlinear relationships of rumen endotoxin and plasma SAA with circulating Ca. Interestingly, plasma Ca reached the asymptotic plateau at 10.6 mg/dL. The increase in rumen endotoxin was associated with an abrupt decrease in plasma Fe (R(2) = 0.91; P < 0.001). A similar relationship, although at a reduced estimation accuracy (R(2) = 0.21; P < 0.01), was observed between rumen endotoxin and plasma Zn. Augmentation of rumen endotoxin and plasma CRP resulted in a positive, biphasic response of plasma Cu. In conclusion, the increase in rumen endotoxin in response to high-grain diets, and the resulting increases in plasma SAA and CRP, were strongly correlated with fluctuations of plasma minerals. Results suggest that new feeding strategies should be developed to curb the release of endotoxin in the rumen fluid to prevent perturbing minerals in the plasma.

  8. Essentiality Is a Strong Determinant of Protein Rates of Evolution during Mutation Accumulation Experiments in Escherichia coli.

    PubMed

    Alvarez-Ponce, David; Sabater-Muñoz, Beatriz; Toft, Christina; Ruiz-González, Mario X; Fares, Mario A

    2016-09-26

    The Neutral Theory of Molecular Evolution is considered the most powerful theory to understand the evolutionary behavior of proteins. One of the main predictions of this theory is that essential proteins should evolve slower than dispensable ones owing to increased selective constraints. Comparison of genomes of different species, however, has revealed only small differences between the rates of evolution of essential and nonessential proteins. In some analyses, these differences vanish once confounding factors are controlled for, whereas in other cases essentiality seems to have an independent, albeit small, effect. It has been argued that comparing relatively distant genomes may entail a number of limitations. For instance, many of the genes that are dispensable in controlled lab conditions may be essential in some of the conditions faced in nature. Moreover, essentiality can change during evolution, and rates of protein evolution are simultaneously shaped by a variety of factors, whose individual effects are difficult to isolate. Here, we conducted two parallel mutation accumulation experiments in Escherichia coli, during 5,500-5,750 generations, and compared the genomes at different points of the experiments. Our approach (a short-term experiment, under highly controlled conditions) enabled us to overcome many of the limitations of previous studies. We observed that essential proteins evolved substantially slower than nonessential ones during our experiments. Strikingly, rates of protein evolution were only moderately affected by expression level and protein length.

  9. Identification of two homologous mitochondrial DNA sequences, which bind strongly and specifically to a mitochondrial protein of Paracentrotus lividus.

    PubMed Central

    Roberti, M; Mustich, A; Gadaleta, M N; Cantatore, P

    1991-01-01

    Using a combination of band shift and DNasel protection experiments, two Paracentrotus lividus mitochondrial sequences, able to bind tightly and selectively to a mitochondrial protein from sea urchin embryos, have been found. The two sequences, which compete with each other for binding to the protein, are located in two genome regions which are thought to contain regulatory signals for mitochondrial replication and transcription. A computer analysis suggests that the sequence TTTTRTANNTCYYATCAYA, common to the two binding regions, is the minimal recognition signal for the binding to the protein. We discuss the hypothesis that the protein binding capacity of these two sequences is involved in the control of sea urchin mtDNA replication during developmental stages. Images PMID:1956785

  10. Macrophages in T cell/histiocyte rich large B cell lymphoma strongly express metal-binding proteins and show a bi-activated phenotype.

    PubMed

    Hartmann, Sylvia; Tousseyn, Thomas; Döring, Claudia; Flüchter, Patricia; Hackstein, Holger; Herreman, An; Ponzoni, Maurilio; de Wolf-Peeters, Chris; Facchetti, Fabio; Gascoyne, Randy D; Küppers, Ralf; Steidl, Christian; Hansmann, Martin-Leo

    2013-12-01

    Abundant macrophage infiltration in tumors often correlates with a poor prognosis. T cell/histiocyte rich large B cell lymphoma (THRLBCL) is a distinct aggressive B cell lymphoma entity showing a high macrophage content. To further elucidate the role of tumor-associated macrophages in THRLBCL, we performed gene expression profiling of microdissected histiocyte subsets of THRLBCL, nodular lymphocyte predominant Hodgkin lymphoma (NLPHL), Piringer lymphadenitis, sarcoidosis, nonspecific lymphadenitis and monocytes from peripheral blood. In a supervised principal component analysis, histiocytes from THRLBCL were most closely related to epithelioid cells from NLPHL, with both types of cells expressing genes related to proinflammatory and regulatory macrophage activity. Moreover, histiocytes from THRLBCL strongly expressed metal-binding proteins like MT2A, by which histiocytes of THRLBCL can be distinguished from the other histiocyte subsets investigated. Interestingly, the validation at the protein level showed a strong expression of TXN, CXCL9, MT2A and SOD2 not only in macrophages of THRLBCL but also in the tumor cells of NLPHL and classical Hodgkin lymphoma (cHL). Overall, the present findings indicate that macrophages in the microenvironment of THRLBCL have acquired a distinct gene expression pattern that is characterized by a mixed M1/M2 phenotype and a strong expression of several metal binding proteins. The microenvironments in NLPHL and THRLBCL appear to have a similar influence on the macrophage phenotype. The high expression of metal binding proteins in histiocytes of THRLBCL may be diagnostically useful, but a potential pathophysiological role remains to be identified.

  11. Hypoxia Strongly Affects Mitochondrial Ribosomal Proteins and Translocases, as Shown by Quantitative Proteomics of HeLa Cells.

    PubMed

    Bousquet, Paula A; Sandvik, Joe Alexander; Arntzen, Magnus Ø; Jeppesen Edin, Nina F; Christoffersen, Stine; Krengel, Ute; Pettersen, Erik O; Thiede, Bernd

    2015-01-01

    Hypoxia is an important and common characteristic of many human tumors. It is a challenge clinically due to the correlation with poor prognosis and resistance to radiation and chemotherapy. Understanding the biochemical response to hypoxia would facilitate the development of novel therapeutics for cancer treatment. Here, we investigate alterations in gene expression in response to hypoxia by quantitative proteome analysis using stable isotope labeling with amino acids in cell culture (SILAC) in conjunction with LCMS/MS. Human HeLa cells were kept either in a hypoxic environment or under normoxic conditions. 125 proteins were found to be regulated, with maximum alteration of 18-fold. In particular, three clusters of differentially regulated proteins were identified, showing significant upregulation of glycolysis and downregulation of mitochondrial ribosomal proteins and translocases. This interaction is likely orchestrated by HIF-1. We also investigated the effect of hypoxia on the cell cycle, which shows accumulation in G1 and a prolonged S phase under these conditions. Implications. This work not only improves our understanding of the response to hypoxia, but also reveals proteins important for malignant progression, which may be targeted in future therapies.

  12. Novel Halomonas sp. B15 isolated from Larnaca Salt Lake in Cyprus that generates vanillin and vanillic acid from ferulic acid.

    PubMed

    Vyrides, Ioannis; Agathangelou, Maria; Dimitriou, Rodothea; Souroullas, Konstantinos; Salamex, Anastasia; Ioannou, Aristostodimos; Koutinas, Michalis

    2015-08-01

    Vanillin is a high value added product with many applications in the food, fragrance and pharmaceutical industries. A natural and low-cost method to produce vanillin is by microbial bioconversions through ferulic acid. Until now, limited microorganisms have been found capable of bioconverting ferulic acid to vanillin at high yield. This study aimed to screen halotolerant strains of bacteria from Larnaca Salt Lake which generate vanillin and vanillic acid from ferulic acid. From a total of 50 halotolenant/halophilic strains 8 grew in 1 g/L ferulic acid and only 1 Halomonas sp. B15 and 3 Halomonas elognata strains were capable of bioconverting ferulic acid to vanillic acid at 100 g NaCl/L. The highest vanillic acid (365 mg/L) at these conditions generated by Halomonas sp. B15 which corresponds to ferulic acid bioconversion yield of 36.5%. Using the resting cell technique with an initial ferulic acid concentration of 0.5 g/L at low salinity, the highest production of vanillin (245 mg/L) took place after 48 h, corresponding to a bioconversion yield of 49%. This is the first reported Halomonas sp. with high yield of vanillin production from ferulic acid at low salinity.

  13. Crystallization and preliminary X-ray analysis of the complex of NADH and 3α-hydroxysteroid dehydrogenase from Pseudomonas sp. B-0831

    SciTech Connect

    Kataoka, Sachiyo; Nakamura, Shota; Ohkubo, Tadayasu; Ueda, Shigeru; Uchiyama, Susumu; Kobayashi, Yuji; Oda, Masayuki

    2006-06-01

    The complex of NADH and 3α-HSD from Pseudomonas sp. B-0831 has been crystallized and X-ray diffraction data have been collected to 1.8 Å resolution. The NAD(P){sup +}-dependent enzyme 3α-hydroxysteroid dehydrogenase (3α-HSD) catalyzes the reversible interconversion of hydroxyl and oxo groups at position 3 of the steroid nucleus. The complex of NADH and 3α-HSD from Pseudomonas sp. B-0831 was crystallized by the hanging-drop vapour-diffusion method. Refinement of crystallization conditions with microseeding improved the quality of the X-ray diffraction data to a resolution of 1.8 Å. The crystals belonged to the orthorhombic space group P2{sub 1}2{sub 1}2{sub 1}, with unit-cell parameters a = 62.46, b = 82.25, c = 86.57 Å, and contained two molecules, reflecting dimer formation of 3α-HSD, in the asymmetric unit.

  14. Investigations of ultrafast ligand rebinding to heme and heme proteins using temperature and strong magnetic field perturbations

    NASA Astrophysics Data System (ADS)

    Zhang, Zhenyu

    This thesis is written to summarize investigations of the mechanisms that underlie the kinetics of diatomic ligand rebinding to the iron atom of the heme group, which is chelated inside heme proteins. The family of heme proteins is a major object of studies for several branches of scientific research activity. Understanding the ligand binding mechanisms and pathways is one of the major goals for biophysics. My interests mainly focus on the physics of this ligand binding process. Therefore, to investigate the problem, isolated from the influence of the protein matrix, Fe-protophorphyrin IX is chosen as the prototype system in my studies. Myoglobin, the most extensively and intensively studied protein, is another ideal system that allows coupling the protein polypeptide matrix into the investigation. A technique to synchro-lock two laser pulse trains electronically is applied to our pump-probe spectroscopic studies. Based on this technique, a two color, fs/ps pump-probe system is developed which extends the temporal window for our investigation to 13ns and fills a gap existing in previous pump-probe investigations. In order to apply this newly-developed pump-probe laser system to implement systematic studies on the kinetics of diatomic ligand (NO, CO, O2) rebinding to heme and heme proteins, several experimental setups are utilized. In Chapter 1, the essential background knowledge, which helps to understand the iron-ligand interaction, is briefly described. In Chapter 2, in addition to a description of the preparation protocols of protein samples and details of the method for data analysis, three home-made setups are described, which include: a picosecond laser regenerative amplifier, a pump-probe application along the bore (2-inch in diameter) of a superconducting magnet and a temperature-controllable cryostat for spinning sample cell. Chapter 3 presents high magnetic field studies of several heme-ligand or protein-ligand systems. Pump-probe spectroscopy is used to

  15. Structural and functional analyses of a strong chitin-binding protein-1 (SCBP-1) from the exoskeleton of the crayfish Procambarus clarkii.

    PubMed

    Suzuki, Michio; Sugisaka-Nobayashi, Arisa; Kogure, Toshihiro; Nagasawa, Hiromichi

    2013-01-01

    The organic matrices in the exoskeleton of the crayfish Procambarus clarkii are classified into three groups depending on solubility; acid soluble, acid insoluble-SDS/dithiothreitol (DTT) soluble, and acid insoluble-SDS/DTT insoluble fractions. In our previous studies, Casp-1 and -2 were identified in the acid soluble fraction, and CAP-1 and -2 were identified in the acid insoluble-SDS/DTT soluble fraction. In this study, acid insoluble-SDS/DTT insoluble materials were digested with proteases and the resulting peptides were purified and sequenced. Based on the sequences, a cDNA encoding this protein was cloned. The whole primary sequence of the matrix protein named strong chitin-binding protein-1 (SCBP-1), was deduced. SCBP-1 consisted of 155 amino acid residues and had a Rebers-Riddiford consensus sequence for chitin binding. A recombinant protein of SCBP-N corresponding to the N-terminal part of SCBP-1 showed no chitin-binding ability, while SCBP-C corresponding to the C-terminal part of SCBP-1, showed weak affinity to chitin. These results suggest that the primary sequence of SCBP-1 does not have strong chitin-binding ability. Therefore, SCBP-1 probably binds covalently to chitin through a particular residue contained in the peptide part that was not obtained by protease digestion.

  16. Strong and widespread action of site-specific positive selection in the snake venom Kunitz/BPTI protein family

    PubMed Central

    Župunski, Vera; Kordiš, Dušan

    2016-01-01

    S1 family of serine peptidases is the largest family of peptidases. They are specifically inhibited by the Kunitz/BPTI inhibitors. Kunitz domain is characterized by the compact 3D structure with the most important inhibitory loops for the inhibition of S1 peptidases. In the present study we analysed the action of site-specific positive selection and its impact on the structurally and functionally important parts of the snake venom Kunitz/BPTI family of proteins. By using numerous models we demonstrated the presence of large numbers of site-specific positively selected sites that can reach between 30–50% of the Kunitz domain. The mapping of the positively selected sites on the 3D model of Kunitz/BPTI inhibitors has shown that these sites are located in the inhibitory loops 1 and 2, but also in the Kunitz scaffold. Amino acid replacements have been found exclusively on the surface, and the vast majority of replacements are causing the change of the charge. The consequence of these replacements is the change in the electrostatic potential on the surface of the Kunitz/BPTI proteins that may play an important role in the precise targeting of these inhibitors into the active site of S1 family of serine peptidases. PMID:27841308

  17. Strong Interaction

    SciTech Connect

    Karsch, F.; Vogelsang, V.

    2009-09-29

    We will give here an overview of our theory of the strong interactions, Quantum Chromo Dynamics (QCD) and its properties. We will also briefly review the history of the study of the strong interactions, and the discoveries that ultimately led to the formulation of QCD. The strong force is one of the four known fundamental forces in nature, the others being the electromagnetic, the weak and the gravitational force. The strong force, usually referred to by scientists as the 'strong interaction', is relevant at the subatomic level, where it is responsible for the binding of protons and neutrons to atomic nuclei. To do this, it must overcome the electric repulsion between the protons in an atomic nucleus and be the most powerful force over distances of a few fm (1fm=1 femtometer=1 fermi=10{sup -15}m), the typical size of a nucleus. This property gave the strong force its name.

  18. Molecular energy dissipation in nanoscale networks of Dentin Matrix Protein 1 is strongly dependent on ion valence

    PubMed Central

    Adams, J; Fantner, G E; Fisher, L W; Hansma, P K

    2008-01-01

    The fracture resistance of biomineralized tissues such as bone, dentin, and abalone is greatly enhanced through the nanoscale interactions of stiff inorganic mineral components with soft organic adhesive components. A proper understanding of the interactions that occur within the organic component, and between the organic and inorganic components, is therefore critical for a complete understanding of the mechanics of these tissues. In this paper, we use Atomic Force Microscope (AFM) force spectroscopy and dynamic force spectroscopy to explore the effect of ionic interactions within a nanoscale system consisting of networks of Dentin Matrix Protein 1 (DMP1) (a component of both bone and dentin organic matrix), a mica surface, and an AFM tip. We find that DMP1 is capable of dissipating large amounts of energy through an ion-mediated mechanism, and that the effectiveness increases with increasing ion valence. PMID:18843380

  19. Strong functional patterns in the evolution of eukaryotic genomes revealed by the reconstruction of ancestral protein domain repertoires

    PubMed Central

    2011-01-01

    Background Genome size and complexity, as measured by the number of genes or protein domains, is remarkably similar in most extant eukaryotes and generally exhibits no correlation with their morphological complexity. Underlying trends in the evolution of the functional content and capabilities of different eukaryotic genomes might be hidden by simultaneous gains and losses of genes. Results We reconstructed the domain repertoires of putative ancestral species at major divergence points, including the last eukaryotic common ancestor (LECA). We show that, surprisingly, during eukaryotic evolution domain losses in general outnumber domain gains. Only at the base of the animal and the vertebrate sub-trees do domain gains outnumber domain losses. The observed gain/loss balance has a distinct functional bias, most strikingly seen during animal evolution, where most of the gains represent domains involved in regulation and most of the losses represent domains with metabolic functions. This trend is so consistent that clustering of genomes according to their functional profiles results in an organization similar to the tree of life. Furthermore, our results indicate that metabolic functions lost during animal evolution are likely being replaced by the metabolic capabilities of symbiotic organisms such as gut microbes. Conclusions While protein domain gains and losses are common throughout eukaryote evolution, losses oftentimes outweigh gains and lead to significant differences in functional profiles. Results presented here provide additional arguments for a complex last eukaryotic common ancestor, but also show a general trend of losses in metabolic capabilities and gain in regulatory complexity during the rise of animals. PMID:21241503

  20. Strong protection against ricin challenge induced by a novel modified ricin A-chain protein in mouse model

    PubMed Central

    Zhang, Tao; Yang, Hao; Kang, Lin; Gao, Shan; Xin, Wenwen; Yao, Wenwu; Zhuang, Xiangjin; Ji, Bin; Wang, Jinglin

    2015-01-01

    Ricin toxin (RT) is an extremely potent toxin derived from the castor bean plant. As a possible bioterrorist weapon, it was categorized as a level B agent in international society. With the growing awareness and concerns of the “white powder incident” in recent years, it is indispensable to develop an effective countermeasure against RT intoxication. In this study we used site-directed mutagenesis and polymerase chain reaction (PCR) techniques to modify the gene of ricin A-chain (RTA). As a result, we have generated a mutated and truncated ricin A-chain (mtRTA) vaccine antigen by E.coli strain. The cytotoxicity assay was used to evaluate the safety of the as-prepared mtRTA antigen, and the results showed that there was no residual toxicity observed when compared to the recombinant RTA (rRTA) or native RT. Furthermore, BALB/c mice were subcutaneously (s.c.) vaccinated with mtRTA 3 times at an interval of 2 weeks, and then the survivals were evaluated after intraperitoneal (i.p.) or intratracheal challenge of RT. The vaccinated mice developed a strong protective immune response that was wholly protective against 40 × LD50 of RT i.p. injection or 20 × LD50 of RT intratracheal spraying. The mtRTA antigen has great potential to be a vaccine candidate for future application in humans. PMID:26038805

  1. Strong protection against ricin challenge induced by a novel modified ricin A-chain protein in mouse model.

    PubMed

    Zhang, Tao; Yang, Hao; Kang, Lin; Gao, Shan; Xin, Wenwen; Yao, Wenwu; Zhuang, Xiangjin; Ji, Bin; Wang, Jinglin

    2015-01-01

    Ricin toxin (RT) is an extremely potent toxin derived from the castor bean plant. As a possible bioterrorist weapon, it was categorized as a level B agent in international society. With the growing awareness and concerns of the "white powder incident" in recent years, it is indispensable to develop an effective countermeasure against RT intoxication. In this study we used site-directed mutagenesis and polymerase chain reaction (PCR) techniques to modify the gene of ricin A-chain (RTA). As a result, we have generated a mutated and truncated ricin A-chain (mtRTA) vaccine antigen by E.coli strain. The cytotoxicity assay was used to evaluate the safety of the as-prepared mtRTA antigen, and the results showed that there was no residual toxicity observed when compared to the recombinant RTA (rRTA) or native RT. Furthermore, BALB/c mice were subcutaneously (s.c.) vaccinated with mtRTA 3 times at an interval of 2 weeks, and then the survivals were evaluated after intraperitoneal (i.p.) or intratracheal challenge of RT. The vaccinated mice developed a strong protective immune response that was wholly protective against 40 × LD50 of RT i.p. injection or 20 × LD50 of RT intratracheal spraying. The mtRTA antigen has great potential to be a vaccine candidate for future application in humans.

  2. Strong immunogenicity and cross-reactivity of Mycobacterium tuberculosis ESX-5 type VII secretion: encoded PE-PPE proteins predicts vaccine potential.

    PubMed

    Sayes, Fadel; Sun, Lin; Di Luca, Mariagrazia; Simeone, Roxane; Degaiffier, Nathalie; Fiette, Laurence; Esin, Semih; Brosch, Roland; Bottai, Daria; Leclerc, Claude; Majlessi, Laleh

    2012-04-19

    The genome of Mycobacterium tuberculosis (Mtb) encodes five type VII secretion systems, ESX-1 to ESX-5, most of which are associated with genes encoding PE/PPE proteins, named after their N-terminal Pro-Glu (PE) or Pro-Pro-Glu (PPE) motifs. Here, we describe the strong T cell immunogenicity of the ESX-5-encoded PE/PPE proteins, which share a large panel of cross-reactive CD4(+) epitopes with substantial numbers of their ESX-5-nonassociated PE/PPE homologs. The immunogenicity of these numerous PE/PPE proteins is dependent on their export by a functional EccD(5), the predicted transmembrane channel of the ESX-5 secretion apparatus. The Mtb Δppe25-pe19 mutant deleted for all ESX-5-associated pe and ppe genes, although highly attenuated in immunocompetent mice, remains able to induce immunity against the ESX-5-associated PE/PPE virulence factors, via cross-reactivity with their numerous homologs, and against the ESX-1 virulence factors ESAT-6/CFP-10. The Δppe25-pe19 strain is strongly protective against Mtb infection in mice and represents a potential antituberculosis vaccine candidate.

  3. Mercury (II) removal by resistant bacterial isolates and mercuric (II) reductase activity in a new strain of Pseudomonas sp. B50A.

    PubMed

    Giovanella, Patricia; Cabral, Lucélia; Bento, Fátima Menezes; Gianello, Clesio; Camargo, Flávio Anastácio Oliveira

    2016-01-25

    This study aimed to isolate mercury resistant bacteria, determine the minimum inhibitory concentration for Hg, estimate mercury removal by selected isolates, explore the mer genes, and detect and characterize the activity of the enzyme mercuric (II) reductase produced by a new strain of Pseudomonas sp. B50A. The Hg removal capacity of the isolates was determined by incubating the isolates in Luria Bertani broth and the remaining mercury quantified by atomic absorption spectrophotometry. A PCR reaction was carried out to detect the merA gene and the mercury (II) reductase activity was determined in a spectrophotometer at 340 nm. Eight Gram-negative bacterial isolates were resistant to high mercury concentrations and capable of removing mercury, and of these, five were positive for the gene merA. The isolate Pseudomonas sp. B50A removed 86% of the mercury present in the culture medium and was chosen for further analysis of its enzyme activity. Mercuric (II) reductase activity was detected in the crude extract of this strain. This enzyme showed optimal activity at pH 8 and at temperatures between 37 °C and 45 °C. The ions NH4(+), Ba(2+), Sn(2+), Ni(2+) and Cd(2+) neither inhibited nor stimulated the enzyme activity but it decreased in the presence of the ions Ca(2+), Cu(+) and K(+). The isolate and the enzyme detected were effective in reducing Hg(II) to Hg(0), showing the potential to develop bioremediation technologies and processes to clean-up the environment and waste contaminated with mercury.

  4. An alternatively spliced surfactant protein B mRNA in normal human lung: disease implication.

    PubMed Central

    Lin, Z; Wang, G; Demello, D E; Floros, J

    1999-01-01

    We identified an alternatively-spliced surfactant protein B (SP-B) mRNA from normal human lung with a 12 nt deletion at the beginning of exon 8. This deletion causes a loss of four amino acids in the SP-B precursor protein. Sequence comparison of the 3' splice sites reveals only one difference in the frequency of U/C in the 11 predominantly-pyrimidine nucleotide tract, 73% for the normal and 45% for the alternatively-spliced SP-B mRNA (77-99% for the consensus sequence). Analysis of SP-B mRNA in lung indicates that the abundance of the alternatively-spliced form is very low and varies among individuals. Although the relative abundance of the deletion form of SP-B mRNA remains constant among normal lungs, it is found with relatively higher abundance in the lungs of some individuals with diseases such as congenital alveolar proteinosis, respiratory distress syndrome, bronchopulmonary dysplasia, alveolar capillary dysplasia and hypophosphatasia. This observation points to the possibility that the alternative splicing is a potential regulatory mechanism of SP-B and may play a role in the pathogenesis of disease under certain circumstances. PMID:10493923

  5. Goose parvovirus structural proteins expressed by recombinant baculoviruses self-assemble into virus-like particles with strong immunogenicity in goose

    SciTech Connect

    Ju, Huanyu; Wei, Na; Wang, Qian; Wang, Chunyuan; Jing, Zhiqiang; Guo, Lu; Liu, Dapeng; Gao, Mingchun; Ma, Bo; Wang, Junwei

    2011-05-27

    Highlights: {yields} All three capsid proteins can be expressed in insect cells in baculovirus expression system. {yields} All three recombinant proteins were spontaneously self-assemble into virus-like particles whose size and appearance were similar to those of native purified GPV virions. {yields} The immunogenicity of GPV-VLPs was better than commercial inactivated vaccine and attenuated vaccine. -- Abstract: Goose parvovirus (GPV), a small non-enveloped ssDNA virus, can cause Derzsy's disease, and three capsid proteins of VP1, VP2, and VP3 are encoded by an overlapping nucleotide sequence. However, little is known on whether recombinant viral proteins (VPs) could spontaneously assemble into virus-like particles (VLPs) in insect cells and whether these VLPs could retain their immunoreactivity and immunogenicity in susceptible geese. To address these issues, genes for these GPV VPs were amplified by PCR, and the recombinant VPs proteins were expressed in insect cells using a baculovirus expression system for the characterization of their structures, immunoreactivity, and immunogenicity. The rVP1, rVP2, and rVP3 expressed in Sf9 cells were detected by anti-GPV sera, anti-VP3 sera, and anti-His antibodies, respectively. Electron microscopy revealed that these rVPs spontaneously assembled into VLPs in insect cells, similar to that of the purified wild-type GPV virions. In addition, vaccination with individual types of VLPs, particularly with the rVP2-VLPs, induced higher titers of antibodies and neutralized different strains of GPVs in primary goose and duck embryo fibroblast cells in vitro. These data indicated that these VLPs retained immunoreactivity and had strong immunogenicity in susceptible geese. Therefore, our findings may provide a framework for development of new vaccines for the prevention of Derzsy's disease and vehicles for the delivery of drugs.

  6. Strong anion exchange liquid chromatographic separation of protein amino acids for natural 13C-abundance determination by isotope ratio mass spectrometry.

    PubMed

    Abaye, Daniel A; Morrison, Douglas J; Preston, Tom

    2011-02-15

    Amino acids are the building blocks of proteins and the analysis of their (13)C abundances is greatly simplified by the use of liquid chromatography (LC) systems coupled with isotope ratio mass spectrometry (IRMS) compared with gas chromatography (GC)-based methods. To date, various cation exchange chromatography columns have been employed for amino acid separation. Here, we report strong anion exchange chromatography (SAX) coupled to IRMS with a Liquiface interface for amino acid δ(13)C determination. Mixtures of underivatised amino acids (0.1-0.5 mM) and hydrolysates of representative proteins (prawns and bovine serum albumin) were resolved by LC/IRMS using a SAX column and inorganic eluents. Background inorganic carbon content was minimised through careful preparation of alkaline reagents and use of a pre-injector on-line carbonate removal device. SAX chromatography completely resolved 11 of the 16 expected protein amino acids following acid hydrolysis in underivatised form. Basic and neutral amino acids were resolved with 35 mM NaOH in isocratic mode. Elution of the aromatic and acidic amino acids required a higher hydroxide concentration (180 mM) and a counterion (NO 3-, 5-25 mM). The total run time was 70 min. The average δ(13)C precision of baseline-resolved peaks was 0.75‰ (range 0.04 to 1.06‰). SAX is a viable alternative to cation chromatography, especially where analysis of basic amino acids is important. The technology shows promise for (13)C amino acid analysis in ecology, archaeology, forensic science, nutrition and protein metabolism.

  7. The regulation of synaptic vesicle recycling by cGMP-dependent protein kinase type II in cerebellar granule cells under strong and sustained stimulation.

    PubMed

    Collado-Alsina, Andrea; Ramírez-Franco, Jorge; Sánchez-Prieto, José; Torres, Magdalena

    2014-06-25

    From the early periods of neurogenesis and migration, up until synaptogenesis, both nitric oxide (NO) and its downstream messenger, cGMP, are thought to influence the development of neurons. The NO/cGMP/cGMP-dependent protein kinase (cGK) pathway regulates the clustering and recruitment of synaptic proteins and vesicles to the synapse, adjusting the exoendocytic cycle to the intensity of activity and accelerating endocytosis following large-scale exocytosis. Here, we show that blockage of the N-methyl-D-aspartate receptor impairs the cycling of synaptic vesicles in a subset of boutons on cerebellar granule cells, an effect that was reversed by increasing cGMP. Furthermore, we demonstrate that presynaptic cGK type II (cGKII) plays a major role in this process. Using the FM1-43 dye to track vesicle recycling, we found that knockdown of cGKII and/or the application of a cGK inhibitor reduced the efficiency of synaptic vesicle recycling to a similar extent. Likewise, in cerebellar granule cells transfected with vGlut1-pHluorin to follow the exoendocytotic cycle, application of a cGK inhibitor slowed vesicle endocytosis when exocytosis was accelerated through strong and sustained stimulation. Additionally, ultrastructural analysis showed that cGKII knockdown or inhibition favored the formation of endosomal-like structures after strong and sustained stimulation. We conclude that cGKII controls the homeostatic balance of vesicle exocytosis and endocytosis in synaptic boutons of rat cerebellar granule cells.

  8. Interfacial reactions of ozone with surfactant protein B in a model lung surfactant system.

    PubMed

    Kim, Hugh I; Kim, Hyungjun; Shin, Young Shik; Beegle, Luther W; Jang, Seung Soon; Neidholdt, Evan L; Goddard, William A; Heath, James R; Kanik, Isik; Beauchamp, J L

    2010-02-24

    Oxidative stresses from irritants such as hydrogen peroxide and ozone (O(3)) can cause dysfunction of the pulmonary surfactant (PS) layer in the human lung, resulting in chronic diseases of the respiratory tract. For identification of structural changes of pulmonary surfactant protein B (SP-B) due to the heterogeneous reaction with O(3), field-induced droplet ionization (FIDI) mass spectrometry has been utilized. FIDI is a soft ionization method in which ions are extracted from the surface of microliter-volume droplets. We report structurally specific oxidative changes of SP-B(1-25) (a shortened version of human SP-B) at the air-liquid interface. We also present studies of the interfacial oxidation of SP-B(1-25) in a nonionizable 1-palmitoyl-2-oleoyl-sn-glycerol (POG) surfactant layer as a model PS system, where competitive oxidation of the two components is observed. Our results indicate that the heterogeneous reaction of SP-B(1-25) at the interface is quite different from that in the solution phase. In comparison with the nearly complete homogeneous oxidation of SP-B(1-25), only a subset of the amino acids known to react with ozone are oxidized by direct ozonolysis in the hydrophobic interfacial environment, both with and without the lipid surfactant layer. Combining these experimental observations with the results of molecular dynamics simulations provides an improved understanding of the interfacial structure and chemistry of a model lung surfactant system subjected to oxidative stress.

  9. [Preparation of strong cation exchange packings based on monodisperse hydrophilic non-porous resins and their application for fast separation of proteins].

    PubMed

    Zhu, Jinxia; Bo, Chunmiao; Gong, Bolin

    2006-03-01

    Monodisperse, 3.0 microm non-porous hydrophilic poly (glycidylmethacrylate-co-ethylenedimethacrylate) particles were prepared by an one-step swelling and polymerization method. The particles were modified to be a strong cation exchange (SCX) stationary phase for high performance liquid chromatography (HPLC) in the following steps. First, the particles were completely hydrolyzed. Second, the hydrolyzed particles were treated with epichlorhydrin followed by another hydrolysis of the newly introduced epoxide groups. Third, the particles were reacted with chlorosulfonic acid. The SCX stationary phase was evaluated in light of the ion exchange property, separability and hydrophilicity on the separation and retention of proteins in detail. Four proteins were quickly separated in 1.0 min with linear gradient elution using the synthesized SCX stationary phase. It was found that it followed ion exchange chromatographic (IEC) retention mechanism. The SCX resin was used for the fast purification of lysozyme from egg white and cytochrome-C from pig heart in 3.0 min with only one step. The results obtained were satisfactory.

  10. AFCo1, a meningococcal B-derived cochleate adjuvant, strongly enhances antibody and T-cell immunity against Plasmodium falciparum merozoite surface protein 4 and 5

    PubMed Central

    Bracho, Gustavo; Zayas, Caridad; Wang, Lina; Coppel, Ross; Pérez, Oliver; Petrovsky, Nikolai

    2009-01-01

    Background Whilst a large number of malaria antigens are being tested as candidate malaria vaccines, a major barrier to the development of an effective vaccine is the lack of a suitable human adjuvant capable of inducing a strong and long lasting immune response. In this study, the ability of AFCo1, a potent T and B cell adjuvant based on cochleate structures derived from meningococcal B outer membrane proteoliposomes (MBOMP), to boost the immune response against two Plasmodium falciparum antigens, merozoite surface protein 4 (MSP4) and 5 (MSP5), was evaluated. Methods Complete Freund's adjuvant (CFA), which is able to confer protection against malaria in animal MSP4/5 vaccine challenge models, was used as positive control adjuvant. MSP4 and 5-specific IgG, delayed-type hypersensitivity (DTH), T-cell proliferation, and cytokine production were evaluated in parallel in mice immunized three times intramuscularly with MSP4 or MSP5 incorporated into AFCo1, synthetic cochleate structures, CFA or phosphate buffered saline. Results AFCo1 significantly enhanced the IgG and T-cell response against MSP4 and MSP5, with a potency equivalent to CFA, with the response being characterized by both IgG1 and IgG2a isotypes, increased interferon gamma production and a strong DTH response, consistent with the ability of AFCo1 to induce Th1-like immune responses. Conclusion Given the proven safety of MBOMP, which is already in use in a licensed human vaccine, AFCo1 could assist the development of human malaria vaccines that require a potent and safe adjuvant. PMID:19250541

  11. Glucocorticoids regulate surfactant protein synthesis in a pulmonary adenocarcinoma cell line

    SciTech Connect

    O'Reilly, M.A.; Gazdar, A.F.; Clark, J.C.; Pilot-Matias, T.J.; Wert, S.E.; Hull, W.M.; Whitsett, J.A. )

    1989-12-01

    Synthesis of pulmonary surfactant proteins SP-A, SP-B, and SP-C was demonstrated in a cell line derived from a human adenocarcinoma of the lung. The cells contained numerous lamellar inclusion bodies and formed organized groups of cells containing well-developed junctional complexes and apical microvillous membranes. Synthesis of SP-A was detected in the cells by enzyme-linked immunoabsorbent assay and by immunoprecipitation of (35S)methionine-labeled protein. SP-A was identified as an Mr 31,000-36,000 polypeptide containing asparagine-linked carbohydrate. Northern blot analysis detected SP-A mRNA of 2.2 kb. Dexamethasone (1-10 nM) enhanced the relative abundance of SP-A mRNA. Despite stimulation of SP-A mRNA, intracellular SP-A content was unaltered or inhibited by dexamethasone. SP-B and SP-C mRNAs and synthesis of the SP-B and SP-C precursors were markedly induced by dexamethasone. ProSP-B was synthesized and secreted primarily as an Mr 42,000-46,000 polypeptide. Proteolysis of the proSP-B resulted in the generation of endoglycosidase F-sensitive Mr = 19,000-21,000 and 25,000-27,000 peptides, which were detected both intra- and extracellularly. SP-C proprotein of Mr = 22,000 and smaller SP-C fragments were detected intracellularly but were not detected in the media. Mature forms of SP-B (Mr = 8,000) and SP-C (Mr = 4,000) were not detected. Glucocorticoids directly enhance the relative synthesis and mRNA of the surfactant proteins SP-A, SP-B, and SP-C. Discrepancies among SP-A mRNA, its de novo synthesis, and cell content suggest that glucocorticoid may alter both pre- and posttranslational factors modulating SP-A expression.

  12. Endogenous proteolytic cleavage of disease-associated prion protein to produce C2 fragments is strongly cell- and tissue-dependent.

    PubMed

    Dron, Michel; Moudjou, Mohammed; Chapuis, Jérôme; Salamat, Muhammad Khalid Farooq; Bernard, Julie; Cronier, Sabrina; Langevin, Christelle; Laude, Hubert

    2010-04-02

    The abnormally folded form of the prion protein (PrP(Sc)) accumulating in nervous and lymphoid tissues of prion-infected individuals can be naturally cleaved to generate a N-terminal-truncated fragment called C2. Information about the identity of the cellular proteases involved in this process and its possible role in prion biology has remained limited and controversial. We investigated PrP(Sc) N-terminal trimming in different cell lines and primary cultured nerve cells, and in the brain and spleen tissue from transgenic mice infected by ovine and mouse prions. We found the following: (i) the full-length to C2 ratio varies considerably depending on the infected cell or tissue. Thus, in primary neurons and brain tissue, PrP(Sc) accumulated predominantly as untrimmed species, whereas efficient trimming occurred in Rov and MovS cells, and in spleen tissue. (ii) Although C2 is generally considered to be the counterpart of the PrP(Sc) proteinase K-resistant core, the N termini of the fragments cleaved in vivo and in vitro can actually differ, as evidenced by a different reactivity toward the Pc248 anti-octarepeat antibody. (iii) In lysosome-impaired cells, the ratio of full-length versus C2 species dramatically increased, yet efficient prion propagation could occur. Moreover, cathepsin but not calpain inhibitors markedly inhibited C2 formation, and in vitro cleavage by cathepsins B and L produced PrP(Sc) fragments lacking the Pc248 epitope, strongly arguing for the primary involvement of acidic hydrolases of the endolysosomal compartment. These findings have implications on the molecular analysis of PrP(Sc) and cell pathogenesis of prion infection.

  13. A yeast two-hybrid screen reveals a strong interaction between the Legionella chaperonin Hsp60 and the host cell small heat shock protein Hsp10.

    PubMed

    Nasrallah, Gheyath K

    2015-06-01

    L. pneumophila is an intracellular bacterium that replicates inside a membrane-bound vacuole called Legionella-containing vacuole (LCV), where it plentifully liberates its HtpB chaperonin. From LCV, HtpB reaches the host cell cytoplasm, where it interacts with SAMDC, a cytoplasmic protein required for synthesis of host polyamines that are important for intracellular growth of L. pneumophila. Additionally, cytoplasmic expression of HtpB in S. cerevisiae induces pseudohyphal growth, and in mammalian cells recruits mitochondria to LCV, and modifies actin microfilaments organization. This led us to hypothesize here that HtpB recruits a protein(s) from eukaryotic cells that is involved in the emergence of the aforementioned phenotypes. To identify this protein, a commercially available HeLa cDNA library was screened using a yeast two-hybrid system. Approximately 5×10(6) yeast clones carrying HeLa cDNA library plasmid were screened. Twenty-one positive clones were identified. DNA sequence analysis revealed that all of these positive clones encoded the mammalian small heat shock protein Hsp10. Based on the fact that chaperonions are required to interact with co-chaperonins to function properly in protein folding, we believe that HtpB recruits the host cell Hsp10 to appropriately interact with SAMDC and to induce the multifunction phenotypes deemed important in L. pneumophila pathogenesis.

  14. The heat treatment and the gelation are strong determinants of the kinetics of milk proteins digestion and of the peripheral availability of amino acids.

    PubMed

    Barbé, Florence; Ménard, Olivia; Le Gouar, Yann; Buffière, Caroline; Famelart, Marie-Hélène; Laroche, Béatrice; Le Feunteun, Steven; Dupont, Didier; Rémond, Didier

    2013-02-15

    This study aimed to determine the kinetics of milk protein digestion and amino acid absorption after ingestion of four dairy matrices by six minipigs: unheated or heated skim milk and corresponding rennet gels. Digestive contents and plasma samples were collected over a 7 h-period after meal ingestion. Gelation of milk slowed down the outflow of the meal from the stomach and the subsequent absorption of amino acids, and decreased their bioavailability in peripheral blood. The gelled rennet matrices also led to low levels of milk proteins at the duodenum. Caseins and β-lactoglobulin, respectively, were sensitive and resistant to hydrolysis in the stomach with the unheated matrices, but showed similar digestion with the heated matrices, with a heat-induced susceptibility to hydrolysis for β-lactoglobulin. These results suggest a significant influence of the meal microstructure (resulting from heat treatment) and macrostructure (resulting from gelation process) on the different steps of milk proteins digestion.

  15. Functional and evolutionary analyses of Helicobacter pylori HP0231 (DsbK) protein with strong oxidative and chaperone activity characterized by a highly diverged dimerization domain.

    PubMed

    Bocian-Ostrzycka, Katarzyna M; Łasica, Anna M; Dunin-Horkawicz, Stanisław; Grzeszczuk, Magdalena J; Drabik, Karolina; Dobosz, Aneta M; Godlewska, Renata; Nowak, Elżbieta; Collet, Jean-Francois; Jagusztyn-Krynicka, Elżbieta K

    2015-01-01

    Helicobacter pylori does not encode the classical DsbA/DsbB oxidoreductases that are crucial for oxidative folding of extracytoplasmic proteins. Instead, this microorganism encodes an untypical two proteins playing a role in disulfide bond formation - periplasmic HP0231, which structure resembles that of EcDsbC/DsbG, and its redox partner, a membrane protein HpDsbI (HP0595) with a β-propeller structure. The aim of presented work was to assess relations between HP0231 structure and function. We showed that HP0231 is most closely related evolutionarily to the catalytic domain of DsbG, even though it possesses a catalytic motif typical for canonical DsbA proteins. Similarly, the highly diverged N-terminal dimerization domain is homologous to the dimerization domain of DsbG. To better understand the functioning of this atypical oxidoreductase, we examined its activity using in vivo and in vitro experiments. We found that HP0231 exhibits oxidizing and chaperone activities but no isomerizing activity, even though H. pylori does not contain a classical DsbC. We also show that HP0231 is not involved in the introduction of disulfide bonds into HcpC (Helicobacter cysteine-rich protein C), a protein involved in the modulation of the H. pylori interaction with its host. Additionally, we also constructed a truncated version of HP0231 lacking the dimerization domain, denoted HP0231m, and showed that it acts in Escherichia coli cells in a DsbB-dependent manner. In contrast, HP0231m and classical monomeric EcDsbA (E. coli DsbA protein) were both unable to complement the lack of HP0231 in H. pylori cells, though they exist in oxidized forms. HP0231m is inactive in the insulin reduction assay and possesses high chaperone activity, in contrast to EcDsbA. In conclusion, HP0231 combines oxidative functions characteristic of DsbA proteins and chaperone activity characteristic of DsbC/DsbG, and it lacks isomerization activity.

  16. Functional and evolutionary analyses of Helicobacter pylori HP0231 (DsbK) protein with strong oxidative and chaperone activity characterized by a highly diverged dimerization domain

    PubMed Central

    Bocian-Ostrzycka, Katarzyna M.; Łasica, Anna M.; Dunin-Horkawicz, Stanisław; Grzeszczuk, Magdalena J.; Drabik, Karolina; Dobosz, Aneta M.; Godlewska, Renata; Nowak, Elżbieta; Collet, Jean-Francois; Jagusztyn-Krynicka, Elżbieta K.

    2015-01-01

    Helicobacter pylori does not encode the classical DsbA/DsbB oxidoreductases that are crucial for oxidative folding of extracytoplasmic proteins. Instead, this microorganism encodes an untypical two proteins playing a role in disulfide bond formation – periplasmic HP0231, which structure resembles that of EcDsbC/DsbG, and its redox partner, a membrane protein HpDsbI (HP0595) with a β-propeller structure. The aim of presented work was to assess relations between HP0231 structure and function. We showed that HP0231 is most closely related evolutionarily to the catalytic domain of DsbG, even though it possesses a catalytic motif typical for canonical DsbA proteins. Similarly, the highly diverged N-terminal dimerization domain is homologous to the dimerization domain of DsbG. To better understand the functioning of this atypical oxidoreductase, we examined its activity using in vivo and in vitro experiments. We found that HP0231 exhibits oxidizing and chaperone activities but no isomerizing activity, even though H. pylori does not contain a classical DsbC. We also show that HP0231 is not involved in the introduction of disulfide bonds into HcpC (Helicobacter cysteine-rich protein C), a protein involved in the modulation of the H. pylori interaction with its host. Additionally, we also constructed a truncated version of HP0231 lacking the dimerization domain, denoted HP0231m, and showed that it acts in Escherichia coli cells in a DsbB-dependent manner. In contrast, HP0231m and classical monomeric EcDsbA (E. coli DsbA protein) were both unable to complement the lack of HP0231 in H. pylori cells, though they exist in oxidized forms. HP0231m is inactive in the insulin reduction assay and possesses high chaperone activity, in contrast to EcDsbA. In conclusion, HP0231 combines oxidative functions characteristic of DsbA proteins and chaperone activity characteristic of DsbC/DsbG, and it lacks isomerization activity. PMID:26500620

  17. StGCPRP, a Potato Gene Strongly Expressed in Stomatal Guard Cells, Defines a Novel Type of Repetitive Proline-Rich Proteins1

    PubMed Central

    Menke, Ulrich; Renault, Nathalie; Mueller-Roeber, Bernd

    2000-01-01

    Guard cells represent a highly differentiated cell type within the epidermis of plant leaves and stems. They respond to many endogenous and environmental signals and thereby modify the size of the stomatal pore they surround. We identified a novel gene that is highly expressed in guard cells of potato (Solanum tuberosum). It encodes a repetitive proline (Pro)-rich protein of 54 kD (491 amino acids) and was named StGCPRP (S. tuberosum guard cell Pro-rich protein). StGCPRP has a bipartite structure. The C-terminal part of StGCPRP contains a high percentage (46%) of Pro residues organized in distinct repetitive sequence motifs, whereas its extended N terminus is essentially free of Pros. StGCPRP represents the first member of a novel class of hybrid Pro-rich proteins that we designated NHyPRPs. In young but not in mature leaves, StGCPRP transcripts were also present at high levels in mesophyll cells (in addition to guard cells), indicating developmental regulation of StGCPRP gene expression. In addition, StGCPRP expression is regulated by environmental factors, as shown by a decrease in StGCPRP transcript levels under drought stress. Two proteins similar to StGCPRP were found to be encoded by the Arabidopsis genome, indicating that NHyPRPs are more widely distributed in higher plants. PMID:10712530

  18. In Vivo-Expressed Proteins of Virulent Leptospira interrogans Serovar Autumnalis N2 Elicit Strong IgM Responses of Value in Conclusive Diagnosis

    PubMed Central

    Raja, Veerapandian; Shanmughapriya, Santhanam; Kanagavel, Murugesan; Artiushin, Sergey C.; Velineni, Sridhar; Timoney, John F.

    2015-01-01

    Leptospirosis is a serious zoonosis that is underdiagnosed because of limited access to laboratory facilities in Southeast Asia, Central and South America, and Oceania. Timely diagnosis of locally distributed serovars of high virulence is crucial for successful care and outbreak management. Using pooled patient sera, an expression gene library of a virulent Leptospira interrogans serovar Autumnalis strain N2 isolated in South India was screened. The identified genes were characterized, and the purified recombinant proteins were used as antigens in IgM enzyme-linked immunosorbent assay (ELISA) either singly or in combination. Sera (n = 118) from cases of acute leptospirosis along with sera (n = 58) from healthy subjects were tested for reactivity with the identified proteins in an ELISA designed to detect specific IgM responses. We have identified nine immunoreactive proteins, ArgC, RecA, GlpF, FliD, TrmD, RplS, RnhB, Lp28.6, and Lrr44.9, which were found to be highly conserved among pathogenic leptospires. Apparently, the proteins ArgC, RecA, GlpF, FliD, TrmD, and Lrr44.9 are expressed during natural infection of the host and undetectable in in vitro cultures. Among all the recombinant proteins used as antigens in IgM ELISA, ArgC had the highest sensitivity and specificity, 89.8% and 95.5%, respectively, for the conclusive diagnosis of leptospirosis. The use of ArgC and RecA in combination for IgM ELISA increased the sensitivity and specificity to 95.7% and 94.9%, respectively. ArgC and RecA thus elicited specific IgM responses and were therefore effective in laboratory confirmation of Leptospira infection. PMID:26607308

  19. A single endoplasmic reticulum aminopeptidase-1 protein allotype is a strong risk factor for Behçet’s disease in HLA-B*51 carriers

    PubMed Central

    Takeuchi, Masaki; Ombrello, Michael J; Kirino, Yohei; Erer, Burak; Tugal-Tutkun, Ilknur; Seyahi, Emire; Özyazgan, Yilmaz; Watts, Norman; Gül, Ahmet; Kastner, Daniel L.; Remmers, Elaine F

    2016-01-01

    Introduction Endoplasmic reticulum aminopeptidase 1 (ERAP1) protein is highly polymorphic with numerous missense amino acid variants. We sought to determine the naturally occurring ERAP1 protein allotypes and their contribution to Behçet’s disease. Methods Genotypes of all reported missense ERAP1 gene variants with 1000 Genomes EUR super-population frequency greater than 1% were determined in 1,900 Behçet’s disease cases and 1,779 controls from Turkey. ERAP1 protein allotypes and their contributions to Behçet’s disease risk were determined by haplotype identification and disease association analyses. Results One ERAP1 protein allotype with 5 non-ancestral amino acids was recessively associated with disease (P = 3.13 × 10−6, odds ratio 2.55, 95% CI 1.70 to 3.82). The ERAP1 association was absent in individuals who lacked HLA-B*51. Individuals who carry HLA-B*51 and who are also homozygous for the haplotype had an increased disease odds compared with those with neither risk factor (P = 4.80 × 10−20, odds ratio 10.96, 95% CI 5.91 to 20.32). Discussion The Behçet’s disease-associated ERAP1 protein allotype was previously shown to have poor peptide trimming activity. Combined with its requirement for HLA-B*51, these data suggest that a hypoactive ERAP1 allotype contributes to Behçet’s disease risk by altering the peptides available for binding to HLA-B*51. PMID:27217550

  20. Directed, strong, and reversible immobilization of proteins tagged with a β-trefoil lectin domain: a simple method to immobilize biomolecules on plain agarose matrixes.

    PubMed

    López-Gallego, Fernando; Acebrón, Ivan; Mancheño, Jose Miguel; Raja, Sebastian; Lillo, M Pilar; Guisán Seijas, Jose Manuel

    2012-03-21

    A highly stable lipase from Geobacillus thermocatenolatus (BTL2) and the enhanced green fluorescent protein from Aquorea victoria (EGFP) were recombinantly produced N-terminally tagged to the lectin domain of the hemolytic pore-forming toxin LSLa from the mushroom Laetiporus sulphureus . Such a domain (LSL(150)), recently described as a novel fusion tag, is based on a β-trefoil scaffold with two operative binding sites for galactose or galactose-containing derivatives. The fusion proteins herein analyzed have enabled us to characterize the binding mode of LSL(150) to polymeric and solid substrates such as agarose beads. The lectin-fusion proteins are able to be quantitatively bound to both cross-linked and non-cross-linked agarose matrixes in a very rapid manner, resulting in a surprisingly dynamic protein distribution inside the porous beads that evolves from heterogeneous to homogeneous along the postimmobilization time. Such dynamic distribution can be related to the reversible nature of the LSL(150)-agarose interaction. Furthermore, this latter interaction is temperature dependent since it is 4-fold stronger when the immobilization takes place at 25 °C than when it does at 4 °C. The strongest lectin-agarose interaction is also quite stable under a survey of different conditions such as high temperatures (up to 60 °C) or high organic solvent concentrations (up to 60% of acetonitrile). Notably, the use of cross-linked agarose would endow the system with more robustness due to its better mechanical properties compared to the noncross-linked one. The stability of the LSL(150)-agarose interaction would prevent protein leaching during the operation process unless high pH media are used. In summary, we believe that the LSL(150) lectin domain exhibits interesting structural features as an immobilization domain that makes it suitable to reversibly immobilize industrially relevant enzymes in very simple carriers as agarose.

  1. The bovine viral diarrhea virus E2 protein formulated with a novel adjuvant induces strong, balanced immune responses and provides protection from viral challenge in cattle.

    PubMed

    Snider, Marlene; Garg, Ravendra; Brownlie, Robert; van den Hurk, Jan V; van Drunen Littel-van den Hurk, Sylvia

    2014-11-28

    Bovine viral diarrhea virus (BVDV) is still one of the most serious pathogens in cattle, meriting the development of improved vaccines. Recently, we developed a new adjuvant consisting of poly[di(sodium carboxylatoethylphenoxy)]-phosphazene (PCEP), either CpG ODN or poly(I:C), and an immune defense regulator (IDR) peptide. As this adjuvant has been shown to mediate the induction of robust, balanced immune responses, it was evaluated in an E2 subunit vaccine against BVDV in lambs and calves. The BVDV type 2 E2 protein was produced at high levels in a mammalian expression system and purified. When formulated with either CpG ODN or poly(I:C), together with IDR and PCEP, the E2 protein elicited high antibody titers and production of IFN-γ secreting cells in lambs. As the immune responses were stronger when poly(I:C) was used, the E2 protein with poly(I:C), IDR and PCEP was subsequently tested in cattle. Robust virus neutralizing antibodies as well as cell-mediated immune responses, including CD8(+) cytotoxic T cell (CTL) responses, were induced. The fact that CTL responses were demonstrated in calves vaccinated with an E2 protein subunit vaccine indicates that this adjuvant formulation promotes cross-presentation. Furthermore, upon challenge with a high dose of virulent BVDV-2, the vaccinated calves showed almost no temperature response, weight loss, leukopenia or virus replication, in contrast to the control animals, which had severe clinical disease. These data suggest that this E2 subunit formulation induces significant protection from BVDV-2 challenge, and thus is a promising BVDV vaccine candidate; in addition, the adjuvant platform has applications in bovine vaccines in general.

  2. Characterization of Streptokinases from Group A Streptococci Reveals a Strong Functional Relationship That Supports the Coinheritance of Plasminogen-binding M Protein and Cluster 2b Streptokinase*

    PubMed Central

    Zhang, Yueling; Liang, Zhong; Hsueh, Hsing-Tse; Ploplis, Victoria A.; Castellino, Francis J.

    2012-01-01

    Group A streptococcus (GAS) strains secrete the protein streptokinase (SK), which functions by activating host human plasminogen (hPg) to plasmin (hPm), thus providing a proteolytic framework for invasive GAS strains. The types of SK secreted by GAS have been grouped into two clusters (SK1 and SK2) and one subcluster (SK2a and SK2b). SKs from cluster 1 (SK1) and cluster 2b (SK2b) display significant evolutionary and functional differences, and attempts to relate these properties to GAS skin or pharynx tropism and invasiveness are of great interest. In this study, using four purified SKs from each cluster, new relationships between plasminogen-binding group A streptococcal M (PAM) protein and SK2b have been revealed. All SK1 proteins efficiently activated hPg, whereas all subclass SK2b proteins only weakly activated hPg in the absence of PAM. Surface plasmon resonance studies revealed that the lower affinity of SK2b to hPg served as the basis for the attenuated activation of hPg by SK2b. Binding of hPg to either human fibrinogen (hFg) or PAM greatly enhanced activation of hPg by SK2b but minimally influenced the already effective activation of hPg by SK1. Activation of hPg in the presence of GAS cells containing PAM demonstrated that PAM is the only factor on the surface of SK2b-expressing cells that enabled the direct activation of hPg by SK2b. As the binding of hPg to PAM is necessary for hPg activation by SK2b, this dependence explains the coinherant relationship between PAM and SK2b and the ability of these particular strains to generate the proteolytic activity that disrupts the innate barriers that limit invasiveness. PMID:23086939

  3. A phenylalanine to serine substitution within an O-protein mannosyltransferase led to strong resistance to PMT-inhibitors in Pichia pastoris.

    PubMed

    Argyros, Rebecca; Nelson, Stephanie; Kull, Angela; Chen, Ming-Tang; Stadheim, Terrance A; Jiang, Bo

    2013-01-01

    Protein O-mannosyltransferases (PMTs) catalyze the initial reaction of protein O-mannosylation by transferring the first mannose unit onto serine and threonine residues of a nascent polypeptide being synthesized in the endoplasmic reticulum (ER). The PMTs are well conserved in eukaryotic organisms, and in vivo defects of these enzymes result in cell death in yeast and congenital diseases in humans. A group of rhodanine-3-acetic acid derivatives (PMTi) specifically inhibits PMT activity both in vitro and in vivo. As such, these chemical compounds have been effectively used to minimize the extent of O-mannosylation on heterologously produced proteins from different yeast expression hosts. However, very little is known about how these PMT-inhibitors interact with the PMT enzyme, or what structural features of the PMTs are required for inhibitor-protein interactions. To better understand the inhibitor-enzyme interactions, and to gain potential insights for developing more effective PMT-inhibitors, we isolated PMTi-resistant mutants in Pichia pastoris. In this study, we report the identification and characterization of a point mutation within the PpPMT2 gene. We demonstrate that this F664S point mutation resulted in a near complete loss of PMTi sensitivity, both in terms of growth-inhibition and reduction in O-mannosylglycan site occupancy. Our results provide genetic evidence demonstrating that the F664 residue plays a critical role in mediating the inhibitory effects of these PMTi compounds. Our data also indicate that the main target of these PMT-inhibitors in P. pastoris is Pmt2p, and that the F664 residue most likely interacts directly with the PMTi-compounds.

  4. Disruption of the ESX-5 system of Mycobacterium tuberculosis causes loss of PPE protein secretion, reduction of cell wall integrity and strong attenuation.

    PubMed

    Bottai, Daria; Di Luca, Mariagrazia; Majlessi, Laleh; Frigui, Wafa; Simeone, Roxane; Sayes, Fadel; Bitter, Wilbert; Brennan, Michael J; Leclerc, Claude; Batoni, Giovanna; Campa, Mario; Brosch, Roland; Esin, Semih

    2012-03-01

    The chromosome of Mycobacterium tuberculosis encodes five type VII secretion systems (ESX-1-ESX-5). While the role of the ESX-1 and ESX-3 systems in M. tuberculosis has been elucidated, predictions for the function of the ESX-5 system came from data obtained in Mycobacterium marinum, where it transports PPE and PE_PGRS proteins and modulates innate immune responses. To define the role of the ESX-5 system in M. tuberculosis, in this study, we have constructed five M. tuberculosis H37Rv ESX-5 knockout/deletion mutants, inactivating eccA(5), eccD(5), rv1794 and esxM genes or the ppe25-pe19 region. Whereas the Mtbrv1794ko displayed no obvious phenotype, the other four mutants showed defects in secretion of the ESX-5-encoded EsxN and PPE41, a representative member of the large PPE protein family. Strikingly, the MtbeccD(5) ko mutant also showed enhanced sensitivity to detergents and hydrophilic antibiotics. When the virulence of the five mutants was evaluated, the MtbeccD(5) ko and MtbΔppe25-pe19 mutants were found attenuated both in macrophages and in the severe combined immune-deficient mouse infection model. Altogether these findings indicate an essential role of ESX-5 for transport of PPE proteins, cell wall integrity and full virulence of M. tuberculosis, thereby opening interesting new perspectives for the study of this human pathogen.

  5. AdoMet radical proteins—from structure to evolution—alignment of divergent protein sequences reveals strong secondary structure element conservation

    PubMed Central

    Nicolet, Yvain; Drennan, Catherine L.

    2004-01-01

    Eighteen subclasses of S-adenosyl-l-methionine (AdoMet) radical proteins have been aligned in the first bioinformatics study of the AdoMet radical superfamily to utilize crystallographic information. The recently resolved X-ray structure of biotin synthase (BioB) was used to guide the multiple sequence alignment, and the recently resolved X-ray structure of coproporphyrinogen III oxidase (HemN) was used as the control. Despite the low 9% sequence identity between BioB and HemN, the multiple sequence alignment correctly predicted all but one of the core helices in HemN, and correctly predicted the residues in the enzyme active site. This alignment further suggests that the AdoMet radical proteins may have evolved from half-barrel structures (αβ)4 to three-quarter-barrel structures (αβ)6 to full-barrel structures (αβ)8. It predicts that anaerobic ribonucleotide reductase (RNR) activase, an ancient enzyme that, it has been suggested, serves as a link between the RNA and DNA worlds, will have a half-barrel structure, whereas the three-quarter barrel, exemplified by HemN, will be the most common architecture for AdoMet radical enzymes, and fewer members of the superfamily will join BioB in using a complete (αβ)8 TIM-barrel fold to perform radical chemistry. These differences in barrel architecture also explain how AdoMet radical enzymes can act on substrates that range in size from 10 atoms to 608 residue proteins. PMID:15289575

  6. [A novel immunization strategy to induce strong humoral responses against HIV-1 using combined DNA, recombinant vaccinia virus and protein vaccines].

    PubMed

    Liu, Chang; Wang, Shu-hui; Ren, Li; Hao, Yan-ling; Zhang, Qi-cheng; Liu, Ying

    2014-11-01

    To optimize the immunization strategy against HIV-1, a DNA vaccine was combined with a recombinant vaccinia virus (rTV) vaccine and a protein vaccine. Immune responses against HIV-1 were detected in 30 female guinea pigs divided into six groups. Three groups of guinea pigs were primed with HIV-1 DNA vaccine three times, boosted with rTV at week 14, and then boosted with gp140 protein at intervals of 4, 8 or 12 weeks. Simultaneously, the other three groups of animals were primed with rTV vaccine once, and then boosted with gp140 after 4, 8 or 12 weeks. The HIV-1 specific binding antibody and neutralizing antibody, in addition to the relative affinity of these antibodies, were detected at different time points after the final administration of vaccine in each group. The DNA-rTV-gp140 immune regimen induced higher titers and affinity levels of HIV-1 gp120/gp140 antibodies and stronger V1V2-gp70 antibodies than the rTV-gp140 regimen. In the guinea pigs that underwent the DNA-rTV-gp140 regimen, the highest V1V2-gp70 antibody was induced in the 12-week-interval group. However, the avidity of antibodies was improved in the 4-week-interval group. Using the rTV-gp140 immunization strategy, guinea pigs boosted at 8 or 12 weeks after rTV priming elicited stronger humoral responses than those boosted at 4 weeks after priming. In conclusion, this study shows that the immunization strategy of HIV-1 DNA vaccine priming, followed by rTV and protein vaccine boosting, could strengthen the humoral response against HIV-1. Longer intervals were better to induce V1V2-gp70-specific antibodies, while shorter intervals were more beneficial to enhance the avidity of antibodies.

  7. Reconstituting redox active centers of heme-containing proteins with biomineralized gold toward peroxidase mimics with strong intrinsic catalysis and electrocatalysis for H2O2 detection.

    PubMed

    Zhang, Liyan; Li, Shuai; Dong, Minmin; Jiang, Yao; Li, Ru; Zhang, Shuo; Lv, Xiaoxia; Chen, Lijun; Wang, Hua

    2017-01-15

    A facile and efficient enzymatic reconstitution methodology has been proposed for high-catalysis peroxidase mimics by remolding the redox active centers of heme-containing proteins with the in-site biomineralized gold using hemoglobin (Hb) as a model. Catalytic hemin (Hem) was extracted from the active centers of Hb for the gold biomineralization and then reconstituted into apoHb to yield the Hem-Au@apoHb nanocomposites showing dramatically improved intrinsic catalysis and electrocatalysis over natural Hb and Hem. The biomineralized gold, on the one hand, would act as "nanowires" to promote the electron transferring of the nanocomposites. On the other hand, it would create a reactivity pathway to pre-organize and accumulate more substrates towards the active sites of the peroxidase mimics. Steady-state kinetics studies indicate that Hem-Au@apoHb could present much higher substrate affinity (lower Michaelis constants) and intrinsic catalysis even than some natural peroxidases. Moreover, the application feasibility of the prepared artificial enzymes was demonstrated by colorimetric assays and direct electrocatalysis for H2O2 sensing, showing a detection limitation low as 0.45μM. Importantly, such a catalysis active-center reconstitution protocol may circumvent the substantial improvement of the intrinsic catalysis and electrocatalysis of diverse heme-containing proteins or enyzmes toward the extensive applications in the chemical, enviromental, and biomedical catalysis fields.

  8. A bacterial transgene for catalase protects translation of d1 protein during exposure of salt-stressed tobacco leaves to strong light.

    PubMed

    Al-Taweel, Khaled; Iwaki, Toshio; Yabuta, Yukinori; Shigeoka, Shigeru; Murata, Norio; Wadano, Akira

    2007-09-01

    During photoinhibition of photosystem II (PSII) in cyanobacteria, salt stress inhibits the repair of photodamaged PSII and, in particular, the synthesis of the D1 protein (D1). We investigated the effects of salt stress on the repair of PSII and the synthesis of D1 in wild-type tobacco (Nicotiana tabacum 'Xanthi') and in transformed plants that harbored the katE gene for catalase from Escherichia coli. Salt stress due to NaCl enhanced the photoinhibition of PSII in leaf discs from both wild-type and katE-transformed plants, but the effect of salt stress was less significant in the transformed plants than in wild-type plants. In the presence of lincomycin, which inhibits protein synthesis in chloroplasts, the activity of PSII decreased rapidly and at similar rates in both types of leaf disc during photoinhibition, and the observation suggests that repair of PSII was protected by the transgene-coded enzyme. Incorporation of [(35)S]methionine into D1 during photoinhibition was inhibited by salt stress, and the transformation mitigated this inhibitory effect. Northern blotting revealed that the level of psbA transcripts was not significantly affected by salt stress or by the transformation. Our results suggest that salt stress enhanced photoinhibition by inhibiting repair of PSII and that the katE transgene increased the resistance of the chloroplast's translational machinery to salt stress by scavenging hydrogen peroxide.

  9. Schistosoma mansoni Infection of Mice, Rats and Humans Elicits a Strong Antibody Response to a Limited Number of Reduction-Sensitive Epitopes on Five Major Tegumental Membrane Proteins

    PubMed Central

    Tremblay, Jacqueline M.; Oliveira, Sergio C.; Da’dara, Akram A.; Skelly, Patrick J.

    2017-01-01

    Schistosomiasis is a major disease of the developing world for which no vaccine has been successfully commercialized. While numerous Schistosoma mansoni worm antigens have been identified that elicit antibody responses during natural infections, little is known as to the identities of the schistosome antigens that are most prominently recognized by antibodies generated through natural infection. Non-reducing western blots probed with serum from schistosome-infected mice, rats and humans on total extracts of larval or adult schistosomes revealed that a small number of antigen bands predominate in all cases. Recognition of each of these major bands was lost when the blots were run under reducing condition. We expressed a rationally selected group of schistosome tegumental membrane antigens in insect host cells, and used the membrane extracts of these cells to unambiguously identify the major antigens recognized by S. mansoni infected mouse, rat and human serum. These results revealed that a limited number of dominant, reduction-sensitive conformational epitopes on five major tegumental surface membrane proteins: SmTsp2, Sm23, Sm29, SmLy6B and SmLy6F, are primary targets of mouse, rat and human S. mansoni infection sera antibodies. We conclude that, Schistosoma mansoni infection of both permissive (mouse) and non-permissive (rat) rodent models, as well as humans, elicit a dominant antibody response recognizing a limited number of conformational epitopes on the same five tegumental membrane proteins. Thus it appears that neither infecting schistosomula nor mature adult schistosomes are substantively impacted by the robust circulating anti-tegumental antibody response they elicit to these antigens. Importantly, our data suggest a need to re-evaluate host immune responses to many schistosome antigens and has important implications regarding schistosome immune evasion mechanisms and schistosomiasis vaccine development. PMID:28095417

  10. Plasma Levels of Acylation-Stimulating Protein Are Strongly Predicted by Waist/Hip Ratio and Correlate with Decreased LDL Size in Men

    PubMed Central

    Saleh, Jumana; Wahab, Rabab A.; Farhan, Hatem; Al-Amri, Issa; Cianflone, Katherine

    2013-01-01

    The association of abdominal obesity with cardiovascular risk is often linked to altered secretion of adipose-derived factors and an abnormal lipid profile including formation of atherogenic small dense low density lipoprotein particles (sdLDL). Acylation-stimulating protein (ASP) is an adipose-derived hormone that exhibits potent lipogenic effects. Plasma ASP levels increase in obesity; however, the association of ASP levels with body fat distribution is not yet established, and no study to date has investigated the association of ASP with LDL size. In this study, we examined the association of ASP levels with abdominal obesity measures and the lipid profile including LDL size in 83 men with a wide range of abdominal girths. Regression analysis showed that waist/hip ratio was the main predictor of ASP levels (β = 0.52, P < 0.0001), significantly followed by decreased LDL size. BMI and TG levels, although positively correlated with ASP levels, were excluded as significant predictors in regression analysis. No correlation was found with LDL-C or apoB levels. ASP levels were 62.5% higher in abdominally obese compared to nonobese men. Waist/hip ratio presenting as the main predictor of ASP levels, suggests increased ASP production by abdominal fat which, as proposed previously, may result from resistance to ASP function causing delayed TG clearance and subsequent formation of atherogenic sdLDL. PMID:24533222

  11. Cell-specific modulation of surfactant proteins by ambroxol treatment

    SciTech Connect

    Seifart, Carola . E-mail: zwiebel@mailer.uni-marburg.de; Clostermann, Ursula; Seifart, Ulf

    2005-02-15

    Ambroxol [trans-4-(2-amino-3,5-dibromobenzylamino)-cyclohexanole hydrochloride], a mucolytic agent, was postulated to provide surfactant stimulatory properties and was previously used to prevent surfactant deficiency. Currently, the underlying mechanisms are not exactly clear. Because surfactant homeostasis is regulated by surfactant-specific proteins (SP), we analyzed protein amount and mRNA expression in whole lung tissue, isolated type II pneumocytes and bronchoalveolar lavage of Sprague-Dawley rats treated with ambroxol i.p. (75 mg/kg body weight, twice a day [every 12 h]). The methods used included competitive polymerase chain reaction (RT-PCR), Northern blotting, Western immunoblotting, and immunohistochemistry. In isolated type II pneumocytes of ambroxol-treated animals, SP-C protein and mRNA content were increased, whereas SP-A, -B and -D protein, mRNA, and immunoreactivity remained unaffected. However, ambroxol treatment resulted in a significant increase of SP-B and in a decrease of SP-D in whole lung tissue with enhanced immunostaining for SP-B in Clara Cells. SP-A and SP-D were significantly decreased in BAL fluid of ambroxol-treated animals. The data suggest that surfactant protein expression is modulated in a cell-specific manner by ambroxol, as type II pneumocytes exhibited an increase in SP-C, whereas Clara cells exhibited an increase in the immunoreactivity for SP-B accounting for the increased SP-B content of whole lung tissue. The results indicate that ambroxol may exert its positive effects, observed in the treatment of diseases related to surfactant deficiency, via modulation of surfactant protein expression.

  12. Cell-specific modulation of surfactant proteins by ambroxol treatment.

    PubMed

    Seifart, Carola; Clostermann, Ursula; Seifart, Ulf; Müller, Bernd; Vogelmeier, Claus; von Wichert, Peter; Fehrenbach, Heinz

    2005-02-15

    Ambroxol [trans-4-(2-amino-3,5-dibromobenzylamino)-cyclohexanole hydrochloride], a mucolytic agent, was postulated to provide surfactant stimulatory properties and was previously used to prevent surfactant deficiency. Currently, the underlying mechanisms are not exactly clear. Because surfactant homeostasis is regulated by surfactant-specific proteins (SP), we analyzed protein amount and mRNA expression in whole lung tissue, isolated type II pneumocytes and bronchoalveolar lavage of Sprague-Dawley rats treated with ambroxol i.p. (75 mg/kg body weight, twice a day [every 12 h]). The methods used included competitive polymerase chain reaction (RT-PCR), Northern blotting, Western immunoblotting, and immunohistochemistry. In isolated type II pneumocytes of ambroxol-treated animals, SP-C protein and mRNA content were increased, whereas SP-A, -B and -D protein, mRNA, and immunoreactivity remained unaffected. However, ambroxol treatment resulted in a significant increase of SP-B and in a decrease of SP-D in whole lung tissue with enhanced immunostaining for SP-B in Clara Cells. SP-A and SP-D were significantly decreased in BAL fluid of ambroxol-treated animals. The data suggest that surfactant protein expression is modulated in a cell-specific manner by ambroxol, as type II pneumocytes exhibited an increase in SP-C, whereas Clara cells exhibited an increase in the immunoreactivity for SP-B accounting for the increased SP-B content of whole lung tissue. The results indicate that ambroxol may exert its positive effects, observed in the treatment of diseases related to surfactant deficiency, via modulation of surfactant protein expression.

  13. Strong conservation of rhoptry-associated-protein-1 (RAP-1) locus organization and sequence among Babesia isolates infecting sheep from China (Babesia motasi-like phylogenetic group).

    PubMed

    Niu, Qingli; Valentin, Charlotte; Bonsergent, Claire; Malandrin, Laurence

    2014-12-01

    Rhoptry-associated-protein 1 (RAP-1) is considered as a potential vaccine candidate due to its involvement in red blood cell invasion by parasites in the genus Babesia. We examined its value as a vaccine candidate by studying RAP-1 conservation in isolates of Babesia sp. BQ1 Ningxian, Babesia sp. Tianzhu and Babesia sp. Hebei, responsible for ovine babesiosis in different regions of China. The rap-1 locus in these isolates has very similar features to those described for Babesia sp. BQ1 Lintan, another Chinese isolate also in the B. motasi-like phylogenetic group, namely the presence of three types of rap-1 genes (rap-1a, rap-1b and rap-1c), multiple conserved rap-1b copies (5) interspaced with more or less variable rap-1a copies (6), and the 3' localization of one rap-1c. The isolates Babesia sp. Tianzhu, Babesia sp. BQ1 Lintan and Ningxian were almost identical (average nucleotide identity of 99.9%) over a putative locus of about 31 Kb, including the intergenic regions. Babesia sp. Hebei showed a similar locus organization but differed in the rap-1 locus sequence, for each gene and intergenic region, with an average nucleotide identity of 78%. Our results are in agreement with 18S rDNA phylogenetic studies performed on these isolates. However, in extremely closely related isolates the rap-1 locus seems more conserved (99.9%) than the 18S rDNA (98.7%), whereas in still closely related isolates the identities are much lower (78%) compared with the 18S rDNA (97.7%). The particularities of the rap-1 locus in terms of evolution, phylogeny, diagnosis and vaccine development are discussed.

  14. Liquid-liquid extraction of strongly protein bound BMS-299897 from human plasma and cerebrospinal fluid, followed by high-performance liquid chromatography/tandem mass spectrometry.

    PubMed

    Xue, Y J; Pursley, Janice; Arnold, Mark

    2007-04-11

    BMS-299897 is a gamma-secretase inhibitor that is being developed for the treatment of Alzheimer's disease. Liquid-liquid extraction (LLE), chromatographic/tandem mass spectrometry (LC/MS/MS) methods have been developed and validated for the quantitation of BMS-299897 in human plasma and cerebrospinal fluid (CSF). Both methods utilized (13)C6-BMS-299897, the stable label isotope analog, as the internal standard. For the human plasma extraction method, two incubation steps were required after the addition of 5 mM ammonium acetate and the internal standard in acetonitrile to release the analyte bound to proteins prior to LLE with toluene. For the human CSF extraction method, after the addition of 0.5 N HCl and the internal standard, CSF samples were extracted with toluene and no incubation was required. The organic layers obtained from both extraction methods were removed and evaporated to dryness. The residues were reconstituted and injected into the LC/MS/MS system. Chromatographic separation was achieved isocratically on a MetaChem C18 Hypersil BDS column (2.0 mm x 50 mm, 3 microm). The mobile phase contained 10 mM ammonium acetate pH 5 and acetonitrile. Detection was by negative ion electrospray tandem mass spectrometry. The standard curves ranged from 1 to 1000 ng/ml for human plasma and 0.25-100 ng/ml for human CSF. Both standard curves were fitted to a 1/x weighted quadratic regression model. For both methods, the intra-assay precision was within 8.2% CV, the inter-assay precision was within 5.4% CV, and assay accuracy was within +/-7.4% of the nominal values. The validation and sample analysis results demonstrated that both methods had acceptable precision and accuracy across the calibration ranges.

  15. Characterization of Ca(2+)-binding sites in the kidney stone inhibitor glycoprotein nephrocalcin using vanadyl ions: different metal binding properties in strong and weak inhibitor proteins revealed by EPR and ENDOR.

    PubMed

    Mustafi, D; Nakagawa, Y

    1996-11-26

    Nephrocalcin (NC), a calcium-binding glycoprotein of 14,000 molecular weight as a monomer, is known to inhibit the growth of calcium oxalate monohydrate (COM) crystals in renal tubules. We have isolated NC from bovine kidney tissue and purified into four isoforms, fractions A-D. NC-A and NC-B strongly inhibit the growth of COM crystals, and NC-C and NC-D inhibit crystal growth weakly. The strongly inhibitor proteins are abundant in normal subjects, whereas stone formers excrete less of NC-A and NC-B and more of NC-C and NC-D. NC-C was characterized with respect to its metal binding sites by using vanadyl ion (VO2+) as a paramagnetic probe in electron paramagnetic resonance (EPR) and electron nuclear double resonance (ENDOR) spectroscopic studies. We demonstrated that VO2+ binds to NC-C with a stoichiometry of metal:protein binding of 4:1 and that VO2+ competes with Ca2+ in binding to NC-C. In NC-C, the metal ion is exposed to solvent water molecules and two water molecules are detected in the inner coordination sphere of the metal ion by ENDOR. In the metal binding environment of NC-A, as reported previously (Mustafi, D., & Nakagawa, Y. (1994) Proc. Natl. Acad. Sci. U.S.A. 91, 11323-11327), inner sphere coordinated water is completely excluded. Based on the results of the metal binding properties in both strong and weak inhibitor proteins, a probable mechanism of inhibition of COM crystal growth by NC has been outlined.

  16. Nearly 1000 Protein Identifications from 50 ng of Xenopus laevis Zygote Homogenate Using Online Sample Preparation on a Strong Cation Exchange Monolith Based Microreactor Coupled with Capillary Zone Electrophoresis.

    PubMed

    Zhang, Zhenbin; Sun, Liangliang; Zhu, Guijie; Cox, Olivia F; Huber, Paul W; Dovichi, Norman J

    2016-01-05

    A sulfonate-silica hybrid strong cation exchange monolith microreactor was synthesized and coupled to a linear polyacrylamide coated capillary for online sample preparation and capillary zone electrophoresis-tandem mass spectrometry (CZE-MS/MS) bottom-up proteomic analysis. The protein sample was loaded onto the microreactor in an acidic buffer. After online reduction, alkylation, and digestion with trypsin, the digests were eluted with 200 mM ammonium bicarbonate at pH 8.2 for CZE-MS/MS analysis using 1 M acetic acid as the background electrolyte. This combination of basic elution and acidic background electrolytes results in both sample stacking and formation of a dynamic pH junction. 369 protein groups and 1274 peptides were identified from 50 ng of Xenopus laevis zygote homogenate, which is comparable with an offline sample preparation method, but the time required for sample preparation was decreased from over 24 h to less than 40 min. Dramatically improved performance was produced by coupling the reactor to a longer separation capillary (∼100 cm) and a Q Exactive HF mass spectrometer. 975 protein groups and 3749 peptides were identified from 50 ng of Xenopus protein using the online sample preparation method.

  17. A truncated receptor-binding domain of MERS-CoV spike protein potently inhibits MERS-CoV infection and induces strong neutralizing antibody responses: implication for developing therapeutics and vaccines.

    PubMed

    Du, Lanying; Kou, Zhihua; Ma, Cuiqing; Tao, Xinrong; Wang, Lili; Zhao, Guangyu; Chen, Yaoqing; Yu, Fei; Tseng, Chien-Te K; Zhou, Yusen; Jiang, Shibo

    2013-01-01

    An emerging respiratory infectious disease with high mortality, Middle East respiratory syndrome (MERS), is caused by a novel coronavirus (MERS-CoV). It was first reported in 2012 in Saudi Arabia and has now spread to eight countries. Development of effective therapeutics and vaccines is crucial to save lives and halt the spread of MERS-CoV. Here, we show that a recombinant protein containing a 212-amino acid fragment (residues 377-588) in the truncated receptor-binding domain (RBD: residues 367-606) of MERS-CoV spike (S) protein fused with human IgG Fc fragment (S377-588-Fc) is highly expressed in the culture supernatant of transfected 293T cells. The purified S377-588-Fc protein efficiently binds to dipeptidyl peptidase 4 (DPP4), the receptor of MERS-CoV, and potently inhibited MERS-CoV infection, suggesting its potential to be further developed as a therapeutic modality for treating MERS-CoV infection and saving the patients' lives. The recombinant S377-588-Fc is able to induce in the vaccinated mice strong MERS-CoV S-specific antibodies, which blocks the binding of RBD to DPP4 receptor and effectively neutralizes MERS-CoV infection. These findings indicate that this truncated RBD protein shows promise for further development as an effective and safe vaccine for the prevention of MERS-CoV infection.

  18. The mitochondrial precursor protein apocytochrome c strongly influences the order of the headgroup and acyl chains of phosphatidylserine dispersions. A sup 2 H and sup 31 P NMR study

    SciTech Connect

    Jordi, W.; de Kroon, A.I.P.M.; Killian, A.; de Kruijff, B. )

    1990-03-06

    Deuterium and phosphorus nuclear magnetic resonance techniques were used to study the interaction of the mitochondrial precursor protein apocytochrome c with headgroup-deuterated (dioleoylphosphatidyl-L-(2-{sup 2}H{sub 1})serine) and acyl chain deuterated (1,2-(11,11-{sup 2}H{sub 2})dioleoylphosphatidylserine) dispersions. Binding of the protein to dioleoylphosphatidylserine liposomes results in phosphorus nuclear magnetic resonance spectra typical of phospholipids undergoing fast axial rotation in extended liquid-crystalline bilayers with a reduced residual chemical shift anisotropy and an increased line width. {sup 2}H NMR spectra on headgroup-deuterated dioleoylphosphatidylserine dispersions showed a decrease in quadrupolar splitting and a broadening of the signal on interaction with apocytochrome c. Addition of increasing amounts of apocytochrome c to the acyl chain deuterated dioleoylphosphatidylserine dispersions results in the gradual appearance of a second component in the spectra with a 44% reduced quadrupolar splitting. Such large reduction of the quadrupolar splitting has never been observed for any protein studied yet. The induction of a new spectral component with a well-defined reduced quadrupolar splitting seems to be confined to the N-terminus since addition of a small hydrophilic amino-terminal peptide (residues 1-38) also induces a second component with a strongly reduced quadrupolar splitting. A chemically synthesized peptide corresponding to amino acid residues 2-17 of the presequence of the mitochondrial protein cytochrome oxidase subunit IV also has a large perturbing effect on the order of the acyl chains, indicating that the observed effects may be a property shared by many mitochondrial precursor proteins. Implications of these data for the import of apocytochrome c into mitochondria will be discussed.

  19. Mature Surfactant Protein-B Expression by Immunohistochemistry as a Marker for Surfactant System Development in the Fetal Sheep Lung.

    PubMed

    Lock, Mitchell C; McGillick, Erin V; Orgeig, Sandra; Zhang, Song; McMillen, I Caroline; Morrison, Janna L

    2015-11-01

    Evaluation of the number of type II alveolar epithelial cells (AECs) is an important measure of the lung's ability to produce surfactant. Immunohistochemical staining of these cells in lung tissue commonly uses antibodies directed against mature surfactant protein (SP)-C, which is regarded as a reliable SP marker of type II AECs in rodents. There has been no study demonstrating reliable markers for surfactant system maturation by immunohistochemistry in the fetal sheep lung despite being widely used as a model to study lung development. Here we examine staining of a panel of surfactant pro-proteins (pro-SP-B and pro-SP-C) and mature proteins (SP-B and SP-C) in the fetal sheep lung during late gestation in the saccular/alveolar phase of development (120, 130, and 140 days), with term being 150 ± 3 days, to identify the most reliable marker of surfactant producing cells in this species. Results from this study indicate that during late gestation, use of anti-SP-B antibodies in the sheep lung yields significantly higher cell counts in the alveolar epithelium than SP-C antibodies. Furthermore, this study highlights that mature SP-B antibodies are more reliable markers than SP-C antibodies to evaluate surfactant maturation in the fetal sheep lung by immunohistochemistry.

  20. Cartilage-specific matrix protein, chondromodulin-I (ChM-I), is a strong angio-inhibitor in endochondral ossification of human neonatal vertebral tissues in vivo: relationship with angiogenic factors in the cartilage.

    PubMed

    Kusafuka, Kimihide; Hiraki, Yuji; Shukunami, Chisa; Kayano, Teruo; Takemura, Tamiko

    2002-01-01

    Although cartilage contains many angiogenic factors during endochondral ossification, it is an avascular tissue. The cartilage-specific non-collagenous matrix protein chondromodulin-I (ChM-I) has been shown to be a strong angio-inhibitor. To elucidate whether ChM-I plays an essential role in angio-inhibition during endochondral ossification in man, we investigated the expression and localization of ChM-I in comparison with those of angiogenic factors and the endothelial cell marker CD34 in human neonatal vertebral tissues. Although invasion of CD34-positive endothelial cells was observed in primary subchondral spongiosa, expression of the marker of endothelial cells, CD34, was not found in neonatal vertebral cartilage matrix. Type II collagen was deposited in all matrices during endochondral ossification, whereas aggrecan was deposited in the matrix of hypertrophic cartilage, especially around lacunae. Vascular endothelial growth factor (VEGF), which is known to be a strong angiogenic factor, was localized in chondrocytes in mature to hypertrophic cartilage and also in bone marrow. Fibroblast growth factor-2 (FGF-2; basic fibroblast growth factor), which is also known to be a strong angiogenic factor, was localized in the cytoplasm of chondrocytes of mature cartilage in human vertebral cartilage tissues. Transforming growth factor (TGF)-beta has been reported to have many functions including angiogenesis, and TGF-beta1 was also localized in mature chondrocytes in endochondral tissues undergoing ossification. On the other hand, the novel cartilage-specific matrix protein ChM-I was localized in interterritorial regions of the matrix in mature to hypertrophic cartilage, especially around lacunae. In conclusion, these observations indicate that ChM-I may serve as a barrier against the angiogenic properties of VEGF, FGF-2 and TGF-beta1 during endochondral ossification, and this matrix molecule may play an essential role in determining the avascular nature of cartilage

  1. Biophysical mimicry of lung surfactant protein B by random nylon-3 copolymers.

    PubMed

    Dohm, Michelle T; Mowery, Brendan P; Czyzewski, Ann M; Stahl, Shannon S; Gellman, Samuel H; Barron, Annelise E

    2010-06-16

    Non-natural oligomers have recently shown promise as functional analogues of lung surfactant proteins B and C (SP-B and SP-C), two helical and amphiphilic proteins that are critical for normal respiration. The generation of non-natural mimics of SP-B and SP-C has previously been restricted to step-by-step, sequence-specific synthesis, which results in discrete oligomers that are intended to manifest specific structural attributes. Here we present an alternative approach to SP-B mimicry that is based on sequence-random copolymers containing cationic and lipophilic subunits. These materials, members of the nylon-3 family, are prepared by ring-opening polymerization of beta-lactams. The best of the nylon-3 polymers display promising in vitro surfactant activities in a mixed lipid film. Pulsating bubble surfactometry data indicate that films containing the most surface-active polymers attain adsorptive and dynamic-cycling properties that surpass those of discrete peptides intended to mimic SP-B. Attachment of an N-terminal octadecanoyl unit to the nylon-3 copolymers, inspired by the post-translational modifications found in SP-C, affords further improvements by reducing the percent surface area compression to reach low minimum surface tension. Cytotoxic effects of the copolymers are diminished relative to that of an SP-B-derived peptide and a peptoid-based mimic. The current study provides evidence that sequence-random copolymers can mimic the in vitro surface-active behavior of lung surfactant proteins in a mixed lipid film. These findings raise the possibility that random copolymers might be useful for developing a lung surfactant replacement, which is an attractive prospect given that such polymers are easier to prepare than are sequence-specific oligomers.

  2. A sugar beet chlorophyll a/b binding protein promoter void of G-box like elements confers strong and leaf specific reporter gene expression in transgenic sugar beet

    PubMed Central

    Stahl, Dietmar J; Kloos, Dorothee U; Hehl, Reinhard

    2004-01-01

    Background Modification of leaf traits in sugar beet requires a strong leaf specific promoter. With such a promoter, expression in taproots can be avoided which may otherwise take away available energy resources for sugar accumulation. Results Suppression Subtractive Hybridization (SSH) was utilized to generate an enriched and equalized cDNA library for leaf expressed genes from sugar beet. Fourteen cDNA fragments corresponding to thirteen different genes were isolated. Northern blot analysis indicates the desired tissue specificity of these genes. The promoters for two chlorophyll a/b binding protein genes (Bvcab11 and Bvcab12) were isolated, linked to reporter genes, and transformed into sugar beet using promoter reporter gene fusions. Transient and transgenic analysis indicate that both promoters direct leaf specific gene expression. A bioinformatic analysis revealed that the Bvcab11 promoter is void of G-box like regulatory elements with a palindromic ACGT core sequence. The data indicate that the presence of a G-box element is not a prerequisite for leaf specific and light induced gene expression in sugar beet. Conclusions This work shows that SSH can be successfully employed for the identification and subsequent isolation of tissue specific sugar beet promoters. These promoters are shown to drive strong leaf specific gene expression in transgenic sugar beet. The application of these promoters for expressing resistance improving genes against foliar diseases is discussed. PMID:15579211

  3. Partially strong WW scattering

    SciTech Connect

    Cheung Kingman; Chiang Chengwei; Yuan Tzuchiang

    2008-09-01

    What if only a light Higgs boson is discovered at the CERN LHC? Conventional wisdom tells us that the scattering of longitudinal weak gauge bosons would not grow strong at high energies. However, this is generally not true. In some composite models or general two-Higgs-doublet models, the presence of a light Higgs boson does not guarantee complete unitarization of the WW scattering. After partial unitarization by the light Higgs boson, the WW scattering becomes strongly interacting until it hits one or more heavier Higgs bosons or other strong dynamics. We analyze how LHC experiments can reveal this interesting possibility of partially strong WW scattering.

  4. Proteins.

    ERIC Educational Resources Information Center

    Doolittle, Russell F.

    1985-01-01

    Examines proteins which give rise to structure and, by virtue of selective binding to other molecules, make genes. Binding sites, amino acids, protein evolution, and molecular paleontology are discussed. Work with encoding segments of deoxyribonucleic acid (exons) and noncoding stretches (introns) provides new information for hypotheses. (DH)

  5. Strong Navajo Marriages

    ERIC Educational Resources Information Center

    Skogrand, Linda; Mueller, Mary Lou; Arrington, Rachel; LeBlanc, Heidi; Spotted Elk, Davina; Dayzie, Irene; Rosenbrand, Reva

    2008-01-01

    The purpose of this qualitative study, conducted in two Navajo Nation chapters, was to learn what makes Navajo marriages strong because no research has been done on this topic. Twenty-one Navajo couples (42 individuals) who felt they had strong marriages volunteered to participate in the study. Couples identified the following marital strengths:…

  6. Protein

    MedlinePlus

    ... Search for: Harvard T.H. Chan School of Public Health Email People Departments Calendar Careers Give my.harvard ... Nutrition Source Harvard T.H. Chan School of Public Health > The Nutrition Source > What Should I Eat? > Protein ...

  7. Protein

    MedlinePlus

    ... Go lean with protein. • Choose lean meats and poultry. Lean beef cuts include round steaks (top loin, ... main dishes. • Use nuts to replace meat or poultry, not in addition to meat or poultry (i. ...

  8. Living Bones, Strong Bones

    NASA Video Gallery

    In this classroom activity, engineering, nutrition, and physical activity collide when students design and build a healthy bone model of a space explorer which is strong enough to withstand increas...

  9. The Strong Nuclear Force

    SciTech Connect

    Lincoln, Don

    2016-05-24

    Scientists are aware of four fundamental forces- gravity, electromagnetism, and the strong and weak nuclear forces. Most people have at least some familiarity with gravity and electromagnetism, but not the other two. How is it that scientists are so certain that two additional forces exist? In this video, Fermilab’s Dr. Don Lincoln explains why scientists are so certain that the strong force exists.

  10. The Strong Nuclear Force

    ScienceCinema

    Lincoln, Don

    2016-07-12

    Scientists are aware of four fundamental forces- gravity, electromagnetism, and the strong and weak nuclear forces. Most people have at least some familiarity with gravity and electromagnetism, but not the other two. How is it that scientists are so certain that two additional forces exist? In this video, Fermilab’s Dr. Don Lincoln explains why scientists are so certain that the strong force exists.

  11. Strong Cosmic Censorship

    NASA Astrophysics Data System (ADS)

    Isenberg, James

    2017-01-01

    The Hawking-Penrose theorems tell us that solutions of Einstein's equations are generally singular, in the sense of the incompleteness of causal geodesics (the paths of physical observers). These singularities might be marked by the blowup of curvature and therefore crushing tidal forces, or by the breakdown of physical determinism. Penrose has conjectured (in his `Strong Cosmic Censorship Conjecture`) that it is generically unbounded curvature that causes singularities, rather than causal breakdown. The verification that ``AVTD behavior'' (marked by the domination of time derivatives over space derivatives) is generically present in a family of solutions has proven to be a useful tool for studying model versions of Strong Cosmic Censorship in that family. I discuss some of the history of Strong Cosmic Censorship, and then discuss what is known about AVTD behavior and Strong Cosmic Censorship in families of solutions defined by varying degrees of isometry, and discuss recent results which we believe will extend this knowledge and provide new support for Strong Cosmic Censorship. I also comment on some of the recent work on ``Weak Null Singularities'', and how this relates to Strong Cosmic Censorship.

  12. Novel influenza virus vectors expressing Brucella L7/L12 or Omp16 proteins in cattle induced a strong T-cell immune response, as well as high protectiveness against B. abortus infection.

    PubMed

    Tabynov, Kaissar; Kydyrbayev, Zhailaubay; Ryskeldinova, Sholpan; Yespembetov, Bolat; Zinina, Nadezhda; Assanzhanova, Nurika; Kozhamkulov, Yerken; Inkarbekov, Dulat; Gotskina, Tatyana; Sansyzbay, Abylai

    2014-04-11

    This paper presents the results of a study of the immunogenicity and protectiveness of new candidate vector vaccine against Brucella abortus - a bivalent vaccine formulation consisting of a mixture of recombinant influenza A subtype H5N1 or H1N1 (viral constructs vaccine formulation) viruses expressing Brucella ribosomal protein L7/L12 and Omp16, in cattle. To increase the effectiveness of the candidate vaccine, adjuvants such as Montanide Gel01 or chitosan were included in its composition. Immunization of cattle (heifers aged 1-1.5 years, 5 animals per group) with the viral constructs vaccine formulation only, or its combination with adjuvants Montanide Gel01 or chitosan, was conducted via the conjunctival method using cross prime (influenza virus subtype H5N1) and booster (influenza virus subtype H1N1) vaccination schedules at an interval of 28 days. Vaccine candidates were evaluated in comparison with the positive (B. abortus S19) and negative (PBS) controls. The viral constructs vaccine formulations, particularly in combination with Montanide Gel01 adjuvant promoted formation of IgG antibodies (with a predominance of antibodies of isotype IgG2a) against Brucella L7/L12 and Omp16 proteins in ELISA. Moreover, these vaccines in cattle induced a strong antigen-specific T-cell immune response, as indicated by a high number of CD4(+) and CD8(+) cells, as well as the concentration of IFN-γ, and most importantly provided a high level of protectiveness comparable to the commercial B. abortus S19 vaccine and superior to the B. abortus S19 vaccine in combination with Montanide Gel01 adjuvant. Based on these findings, we recommended the bivalent vaccine formulation containing the adjuvant Montanide Gel01 for practical use in cattle.

  13. A mutation in the surfactant protein B gene responsible for fatal neonatal respiratory disease in multiple kindreds.

    PubMed Central

    Nogee, L M; Garnier, G; Dietz, H C; Singer, L; Murphy, A M; deMello, D E; Colten, H R

    1994-01-01

    To determine the molecular defect accounting for the deficiency of pulmonary surfactant protein B (SP-B) in full-term neonates who died from respiratory failure associated with alveolar proteinosis, the sequence of the SP-B transcript in affected infants was ascertained. A frameshift mutation consisting of a substitution of GAA for C in codon 121 of the SP-B cDNA was identified. The three affected infants in the index family were homozygous for this mutation, which segregated in a fashion consistent with autosomal recessive inheritance of disease. The same mutation was found in two other unrelated infants who died from alveolar proteinosis, one of whom was also homozygous, and in the parents of an additional unrelated, affected infant, but was not observed in 50 control subjects. We conclude that this mutation is responsible for SP-B deficiency and neonatal alveolar proteinosis in multiple families and speculate that the disorder is more common than was recognized previously. Images PMID:8163685

  14. On Strong Anticipation

    PubMed Central

    Stepp, N.; Turvey, M. T.

    2009-01-01

    We examine Dubois's (2003) distinction between weak anticipation and strong anticipation. Anticipation is weak if it arises from a model of the system via internal simulations. Anticipation is strong if it arises from the system itself via lawful regularities embedded in the system's ordinary mode of functioning. The assumption of weak anticipation dominates cognitive science and neuroscience and in particular the study of perception and action. The assumption of strong anticipation, however, seems to be required by anticipation's ubiquity. It is, for example, characteristic of homeostatic processes at the level of the organism, organs, and cells. We develop the formal distinction between strong and weak anticipation by elaboration of anticipating synchronization, a phenomenon arising from time delays in appropriately coupled dynamical systems. The elaboration is conducted in respect to (a) strictly physical systems, (b) the defining features of circadian rhythms, often viewed as paradigmatic of biological behavior based in internal models, (c) Pavlovian learning, and (d) forward models in motor control. We identify the common thread of strongly anticipatory systems and argue for its significance in furthering understanding of notions such as “internal”, “model” and “prediction”. PMID:20191086

  15. Yugoslav strong motion network

    NASA Astrophysics Data System (ADS)

    Mihailov, Vladimir

    1985-04-01

    Data concerning ground motion and the response of structures during strong earthquakes are necessary for seismic hazard evaluation and the definition of design criteria for structures to be constructed in seismically active zones. The only way to obtain such data is the installation of a strong-motion instrument network. The Yugoslav strong-motion programme was created in 1972 to recover strong-motion response data used by the structural engineering community in developing earthquake resistant design. Instruments, accelerographs SMA-1 and seismoscopes WM-1, were installed in free-field stations and on structures (high-rise buildings, dams, bridges, etc.). A total number of 176 accelerographs and 137 seismoscopes have been installed and are operating in Yugoslavia. The strong-motion programme in Yugoslavia consists of five subactivities: network design, network operation, data processing, network management and research as well as application. All these activities are under the responsibility of IZIIS in cooperation with the Yugoslav Association of Seismology. By 1975 in the realisation of this project participated the CALTECH as cooperative institution in the joint American-Yugoslav cooperative project. The results obtained which are presented in this paper, and their application in the aseismic design justify the necessity for the existence of such a network in Yugoslavia.

  16. Strongly correlated Bose gases

    NASA Astrophysics Data System (ADS)

    Chevy, F.; Salomon, C.

    2016-10-01

    The strongly interacting Bose gas is one of the most fundamental paradigms of quantum many-body physics and the subject of many experimental and theoretical investigations. We review recent progress on strongly correlated Bose gases, starting with a description of beyond mean-field corrections. We show that the Efimov effect leads to non universal phenomena and to a metastability of the low temperature Bose gas through three-body recombination to deeply bound molecular states. We outline differences and similarities with ultracold Fermi gases, discuss recent experiments on the unitary Bose gas, and finally present a few perspectives for future research.

  17. Partners: Forging Strong Relationships.

    ERIC Educational Resources Information Center

    Spears, Ellen, Ed.

    1999-01-01

    This newsletter issue asserts that sound, effective relationships in which diverse groups of people and organizations work together toward a common goal are the basis of the collaborative efforts in education that can accomplish change. The first article, "Partners: Forging Strong Relationships" (Sarah E. Torian), briefly describes the…

  18. Strong Little Magnets

    ERIC Educational Resources Information Center

    Moloney, Michael J.

    2007-01-01

    Did you know that some strong little cylindrical magnets available in local hardware stores can have an effective circumferential current of 2500 A? This intriguing information can be obtained by hanging a pair of magnets at the center of a coil, as shown in Fig. 1, and measuring the oscillation frequency as a function of coil current.

  19. Mucosal Administration of CpG Oligodeoxynucleotide Elicits Strong CC and CXC Chemokine Responses in the Vagina and Serves as a Potent Th1-Tilting Adjuvant for Recombinant gD2 Protein Vaccination against Genital Herpes

    PubMed Central

    Tengvall, Sara; Lundqvist, Annika; Eisenberg, Roselyn J.; Cohen, Gary H.; Harandi, Ali M.

    2006-01-01

    Although sexually transmitted pathogens are capable of inducing pathogen-specific immune responses, vaginal administration of nonreplicating antigens elicits only weak, nondisseminating immune responses. The present study was undertaken to examine the potential of CpG-containing oligodeoxynucleotide (CpG ODN) for induction of chemokine responses in the genital tract mucosa and also as a vaginal adjuvant in combination with glycoprotein D of herpes simplex virus type 2 (HSV-2) for induction of antigen-specific immune responses. We found that a single intravaginal administration of CpG ODN in mice stimulates a rapid and potent response of CC chemokines macrophage inflammatory protein 1α (MIP-1α), MIP-1β, and RANTES as well as of CXC chemokines MIP-2 and IP-10 in the vagina and/or the genital lymph nodes. Importantly, intravaginal vaccination with recombinant gD2 in combination with CpG ODN gave rise to a strong antigen-specific Th1-like immune response in the genital lymph nodes as well as the spleens of the vaccinated mice. Further, such an immunization scheme conferred both systemic and mucosal immunoglobulin G antibody responses as well as protection against an otherwise lethal vaginal challenge with HSV-2. These results illustrate the potential of CpG ODN for induction of potent chemokine responses in the genital tract and also as a vaginal adjuvant for generation of Th1-type mucosal and systemic immune responses towards a nonreplicating antigen derived from a sexually transmitted pathogen. These data have implications for the development of a mucosal vaccine against genital herpes and possibly other sexually transmitted diseases. PMID:16699008

  20. Strongly Regular Graphs,

    DTIC Science & Technology

    1973-10-01

    The theory of strongly regular graphs was introduced by Bose r7 1 in 1963, in connection with partial geometries and 2 class association schemes. One...non adjacent vertices is constant and equal to ~. We shall denote by ~(p) (reap.r(p)) the set of vertices adjacent (resp.non adjacent) to a vertex p...is the complement of .2’ if the set of vertices of ~ is the set of vertices of .2’ and if two vertices in .2’ are adjacent if and only if they were

  1. Electromagnetic strong plasma turbulence

    SciTech Connect

    Melatos, A.; Jenet, F. A.; Robinson, P. A.

    2007-02-15

    The first large-scale simulations of continuously driven, two-dimensional electromagnetic strong plasma turbulence are performed, for electron thermal speeds 0.01c{<=}v{<=}0.57c, by integrating the Zakharov equations for coupled Langmuir and transverse (T) waves near the plasma frequency. Turbulence scalings and wave number spectra are calculated, a transition is found from a mix of trapped and free T eigenstates for v{>=}0.1c to just free eigenstates for v{<=}0.1c, and wave energy densities are observed to undergo slow quasiperiodic oscillations.

  2. Strongly correlated materials.

    PubMed

    Morosan, Emilia; Natelson, Douglas; Nevidomskyy, Andriy H; Si, Qimiao

    2012-09-18

    Strongly correlated materials are profoundly affected by the repulsive electron-electron interaction. This stands in contrast to many commonly used materials such as silicon and aluminum, whose properties are comparatively unaffected by the Coulomb repulsion. Correlated materials often have remarkable properties and transitions between distinct, competing phases with dramatically different electronic and magnetic orders. These rich phenomena are fascinating from the basic science perspective and offer possibilities for technological applications. This article looks at these materials through the lens of research performed at Rice University. Topics examined include: Quantum phase transitions and quantum criticality in "heavy fermion" materials and the iron pnictide high temperature superconductors; computational ab initio methods to examine strongly correlated materials and their interface with analytical theory techniques; layered dichalcogenides as example correlated materials with rich phases (charge density waves, superconductivity, hard ferromagnetism) that may be tuned by composition, pressure, and magnetic field; and nanostructure methods applied to the correlated oxides VO₂ and Fe₃O₄, where metal-insulator transitions can be manipulated by doping at the nanoscale or driving the system out of equilibrium. We conclude with a discussion of the exciting prospects for this class of materials.

  3. Strong Poison Revisited

    SciTech Connect

    Prince, R.C.; Gailer, J.; Gunson, D.E.; Turner, R.J.; George, G.N.; Pickering, I.J.

    2009-06-04

    Selenium in the form of selenocysteine plays an essential role in a number of proteins, but its role in non-enzymatic biochemistry is also important. In this short review we discuss the interactions between inorganic selenium, arsenic and mercury under physiological conditions, especially in the presence of glutathione. This chemistry is obviously important in making the arsenic and mercury unavailable for more toxic interactions, but in the process it suggests that a side-effect of chronic arsenic and/or mercury exposure is likely to be functional selenium deficiency.

  4. Quine's 'needlessly strong' holism.

    PubMed

    Verhaegh, Sander

    2017-02-01

    Quine is routinely perceived as having changed his mind about the scope of the Duhem-Quine thesis, shifting from what has been called an 'extreme holism' to a more moderate view. Where the Quine of 'Two Dogmas of Empiricism' argues that "the unit of empirical significance is the whole of science" (1951, 42), the later Quine seems to back away from this "needlessly strong statement of holism" (1991, 393). In this paper, I show that the received view is incorrect. I distinguish three ways in which Quine's early holism can be said to be wide-scoped and show that he has never changed his mind about any one of these aspects of his early view. Instead, I argue that Quine's apparent change of mind can be explained away as a mere shift of emphasis.

  5. Strong, Lightweight, Porous Materials

    NASA Technical Reports Server (NTRS)

    Leventis, Nicholas; Meador, Mary Ann B.; Johnston, James C.; Fabrizio, Eve F.; Ilhan, Ulvi

    2007-01-01

    A new class of strong, lightweight, porous materials has been invented as an outgrowth of an effort to develop reinforced silica aerogels. The new material, called X-Aerogel is less hygroscopic, but no less porous and of similar density to the corresponding unmodified aerogels. However, the property that sets X-Aerogels apart is their mechanical strength, which can be as much as two and a half orders of magnitude stronger that the unmodified aerogels. X-Aerogels are envisioned to be useful for making extremely lightweight, thermally insulating, structural components, but they may also have applications as electrical insulators, components of laminates, catalyst supports, templates for electrode materials, fuel-cell components, and filter membranes.

  6. Segregated ordered lipid phases and protein-promoted membrane cohesivity are required for pulmonary surfactant films to stabilize and protect the respiratory surface.

    PubMed

    Bernardino de la Serna, Jorge; Vargas, Rodolfo; Picardi, Victoria; Cruz, Antonio; Arranz, Rocío; Valpuesta, José M; Mateu, Leonardo; Pérez-Gil, Jesús

    2013-01-01

    Pulmonary surfactant is a lipid-protein complex essential to stabilize alveoli, by forming surface active films able to reach and sustain very low surface tensions (< 2 mN m(-1)) during the film compression that occurs at end-expiration. The particular lipid composition of surfactant, including a high proportion of dipalmitoylphosphatidylcholine (DPPC), induces segregation of fluid ordered and disordered phases in surfactant membranes and films at physiological temperatures. The segregation of DPPC-enriched ordered phase has been related with the ability of surfactant films to produce very low tensions, while the presence in surfactant of two specific hydrophobic polypeptides, SP-B and SP-C, is absolutely required to facilitate surfactant dynamics, including film formation and re-spreading during expansion at inspiration. In the present study, we have used X-ray scattering to analyze the structure of (1) whole native surfactant membranes purified from porcine lungs, (2) membranes reconstituted from the organic extract of surfactant containing the full lipid complement and the physiological proportion of SP-B and SP-C, and (3) membranes reconstituted from the lipid fraction of surfactant depleted of proteins. Small angle X-ray scattering data from whole surfactant or from membranes reconstituted from surfactant organic extract indicated the co-existence of two lamellar phases with different thicknesses. Such phase coexistence disappeared upon heating of the samples at temperatures above physiological values. When assessed in a captive bubble surfactometer, which mimics interfacial compression-expansion dynamics, the ability of surfactant films to produce very low tensions is only maintained at temperatures permitting the coexistence of the two lamellar phases. On the other hand, membranes reconstituted in the absence of proteins produced diffractograms indicative of the existence of a single dominant lamellar phase at all temperatures. These data suggest that SP-B

  7. Foreshocks of strong earthquakes

    NASA Astrophysics Data System (ADS)

    Guglielmi, A. V.; Sobisevich, L. E.; Sobisevich, A. L.; Lavrov, I. P.

    2014-07-01

    The specific enhancement of ultra-low-frequency (ULF) electromagnetic oscillations a few hours prior to the strong earthquakes, which was previously mentioned in the literature, motivated us to search for the distinctive features of the mechanical (foreshock) activity of the Earth's crust in the epicentral zones of the future earthquakes. Activation of the foreshocks three hours before the main shock is revealed, which is roughly similar to the enhancement of the specific electromagnetic ULF emission. It is hypothesized that the round-the-world seismic echo signals from the earthquakes, which form the peak of energy release 2 h 50 min before the main events, act as the triggers of the main shocks due to the cumulative action of the surface waves converging to the epicenter. It is established that the frequency of the fluctuations in the foreshock activity decreases at the final stages of the preparation of the main shocks, which probably testifies to the so-called mode softening at the approach of the failure point according to the catastrophe theory.

  8. Strong-interaction nonuniversality

    SciTech Connect

    Volkas, R. R.; Foot, R.; He, X.; Joshi, G. C.

    1989-07-01

    The universal QCD color theory is extended to an SU(3)/sub 1//direct product/SU(3)/sub 2//direct product/SU(3)/sub 3/ gauge theory, where quarks of the /ital i/th generation transform as triplets under SU(3)/sub /ital i// and singlets under the other two factors. The usual color group is then identified with the diagonal subgroup, which remains exact after symmetry breaking. The gauge bosons associated with the 16 broken generators then form two massive octets under ordinary color. The interactions between quarks and these heavy gluonlike particles are explicitly nonuniversal and thus an exploration of their physical implications allows us to shed light on the fundamental issue of strong-interaction universality. Nonuniversality and weak flavor mixing are shown to generate heavy-gluon-induced flavor-changing neutral currents. The phenomenology of these processes is studied, as they provide the major experimental constraint on the extended theory. Three symmetry-breaking scenarios are presented. The first has color breaking occurring at the weak scale, while the second and third divorce the two scales. The third model has the interesting feature of radiatively induced off-diagonal Kobayashi-Maskawa matrix elements.

  9. Studies on Strong Interactions

    NASA Astrophysics Data System (ADS)

    Coriano, Claudio

    Five studies, four in Quantum field theory and one in fermionic molecular dynamics are presented. In the first study, introduced in chapter one and developed in chapter two of this dissertation, we formulate an extension of QCD sum rules to Compton scattering of the pion at intermediate energy. The chapter is based on the research paper Fixed angle pion Compton scattering and QCD sum rules by Prof. George Sterman and the author, which has been submitted for publication as a regular article. In chapter 3 we discuss the relation between traditional bosonic exchange models of nuclear strong interaction and soliton models, in the particular case of the sine-Gordon model. The chapter is based on the research paper "Scattering in soliton models and bosonic exchange descriptions", by R. R. Parwani, H. Yamagishi, I. Zahed and the author, and is published in Phys. Rev. D 45 (1992), 2542. A preprint of this paper (Preprint 1) has been included as an Appendix to the Chapter. In Chapter 4 we discuss aspects of the propagation of quantized fields in classical backgrounds, using the light-cone expansion of the propagator. The chapter is based on the research papers "Electrodynamics in the presence of an axion", published by the author in Modern Physics Letters A 7 (1992), 1253, and on the paper "Singularity of Green's function and the effective action in massive Yang Mills theories, by Prof. H. Yamagishi and the author. This last paper is published in Physical Review D 41 (1990), 3226 and its reprint appears in the final part of the Chapter (Reprint 1). In chapter 5, entitled "On the time dependent Rayleigh-Ritz equations", we discuss aspects of the variational approach to fermionic molecular dynamics. This investigation by R. Parwani, H. Yamagishi and the author has been published in Nucl. Physics A 522 (1991), 591. A preprint of this research paper has been inserted in the final part of the Chapter (Preprint 2).

  10. The immunodominant T helper 2 (Th2) response elicited in BALB/c mice by the Leishmania LiP2a and LiP2b acidic ribosomal proteins cannot be reverted by strong Th1 inducers.

    PubMed

    Iborra, S; Abánades, D R; Parody, N; Carrión, J; Risueño, R M; Pineda, M A; Bonay, P; Alonso, C; Soto, M

    2007-11-01

    The search for disease-associated T helper 2 (Th2) Leishmania antigens and the induction of a Th1 immune response to them using defined vaccination protocols is a potential strategy to induce protection against Leishmania infection. Leishmania infantum LiP2a and LiP2b acidic ribosomal protein (P proteins) have been described as prominent antigens during human and canine visceral leishmaniasis. In this study we demonstrate that BALB/c mice infected with Leishmania major develop a Th2-like humoral response against Leishmania LiP2a and LiP2b proteins and that the same response is induced in BALB/c mice when the parasite P proteins are immunized as recombinant molecules without adjuvant. The genetic immunization of BALB/c mice with eukaryotic expression plasmids coding for these proteins was unable to redirect the Th2-like response induced by these antigens, and only the co-administration of the recombinant P proteins with CpG oligodeoxynucleotides (CpG ODN) promoted a mixed Th1/Th2 immune response. According to the preponderance of a Th2 or mixed Th1/Th2 responses elicited by the different regimens of immunization tested, no evidence of protection was observed in mice after challenge with L. major. Although alterations of the clinical outcome were not detected in mice presensitized with the P proteins, the enhanced IgG1 and interleukin (IL)-4 response against total Leishmania antigens in these mice may indicate an exacerbation of the disease.

  11. Adsorption of peptides and small proteins with control access polymer permeation to affinity binding sites. Part II: Polymer permeation-ion exchange separation adsorbents with polyethylene glycol and strong anion exchange groups.

    PubMed

    González-Ortega, Omar; Porath, Jerker; Guzmán, Roberto

    2012-03-02

    In chromatographic separations, the most general problem in small biomolecule isolation and purification is that such biomolecules are usually found in extremely low concentrations together with high concentrations of large molecular weight proteins. In the first part of this work, adsorption and size exclusion chromatography (AdSEC) controlled access media, using polyethylene glycol (PEG) as a semi-permeable barrier on a polysaccharide Immobilized Metal Affinity Chromatography (IMAC) matrix was synthesized and used to develop chromatographic adsorbents that preferentially adsorb and separate low molecular weight biomolecules while rejecting large molecular weight proteins. In this second part, we expand the concept of controlled access polymer permeation adsorption (CAPPA) media by grafting polyethylene glycol (PEG) on a high capacity polysaccharide ion exchange (IEX) chromatographic resin where PEG acts as a semi-permeable barrier that preferentially allows the permeation of small molecules while rejecting large ones. The IEX resin bearing quaternary ammonium groups binds permeated biomolecules according to their ion exchange affinity while excluding large biomolecules by the PEG barrier and thus cannot compete for the binding sites. This new AdSEC media was used to study the retention of peptides and proteins covering a wide range of molecular weights from 1 to 150 kDa. The effect of protein molecular weight towards retention by ion exchange was performed using pure protein solutions. Recovery of insulin from insulin-spiked human serum and insulin-spiked human urine was evaluated under polymer controlled permeation conditions. The CAPPA media consisted of agarose beads modified with amino-PEG-methoxy and with trimethyl ammonium groups, having chloride capacities between 20 and 40 μeq/mL and were effective in rejecting high molecular weight proteins while allowing the preferential adsorption of small proteins and peptides.

  12. [Surfactant protein and thyroid transcription factor 1 in pleuro-pulmonary neoplasia. Immunohistochemical study].

    PubMed

    Dessy, E; Falleni, M; Del Curto, B; Braidotti, P; Pietra, G G

    2000-12-01

    Aim of this work was to investigate the ability of the antibodies against Surfactant proteins (SP) and Thyroid transcription factor 1 (TTF-1) to distinguish primary neoplasms of the lung from metastatic carcinomas to the lung and pleural mesotheliomas. We evaluated the immunohistochemical expression of the antibodies anti SP-A, SP-B, pro SP-C, SP-D, and TTF-1 in a series of 56 primary lung carcinomas, 9 metastatic carcinomas to the lung, 5 pleural mesotheliomas and 8 non-pulmonary carcinomas. Among primary lung neoplasms, only adenocarcinomas immunostained for all SP (specificity = 1; total sensitivity = 0.52). TTF-1 had an excellent specificity (= 1), but a weak sensitivity (= 0.34) in recognizing primary lung carcinomas. TTF-1 was present in lung adenocarcinomas which were negative for SPs; however it failed to distinguish the subtypes. Pleural mesotheliomas, pulmonary metastases and non-pulmonary carcinomas were not immunoreactive for SP-A, SP-B, SP-D, and TTF-1. Pro SP-C was positive also in the adenocarcinomas of the large bowel and in their pulmonary and nodal metastases. These results demonstrate that the combined use of antibodies anti SP-A, SP-B and TTF-1 is the best association in distinguishing primary lung carcinomas from metastatic carcinomas to the lung and pleural mesotheliomas.

  13. NY-ESO-1 Protein Cancer Vaccine With Poly-ICLC and OK-432: Rapid and Strong Induction of NY-ESO-1-specific Immune Responses by Poly-ICLC.

    PubMed

    Takeoka, Tomohira; Nagase, Hirotsugu; Kurose, Koji; Ohue, Yoshihiro; Yamasaki, Makoto; Takiguchi, Shuji; Sato, Eiichi; Isobe, Midori; Kanazawa, Takayuki; Matsumoto, Mitsunobu; Iwahori, Kota; Kawashima, Atsunari; Morimoto-Okazawa, Akiko; Nishikawa, Hiroyoshi; Oka, Mikio; Pan, Linda; Venhaus, Ralph; Nakayama, Eiichi; Mori, Masaki; Doki, Yuichiro; Wada, Hisashi

    2017-03-23

    We conducted a clinical trial of a cancer vaccine using NY-ESO-1 protein with polyinosinic-polycytidylic acid-poly-L-lysine carboxymethylcellulose (poly-ICLC) and/or OK-432 against solid tumors. A total of 15 patients were sequentially enrolled in 4 cohorts. Patients in cohort 1 received NY-ESO-1 protein; cohort 2a received NY-ESO-1 protein+OK-432; cohort 2b received NY-ESO-1 protein+poly-ICLC; cohort 3 received NY-ESO-1 protein+OK-432+poly-ICLC with Montanide ISA-51. The endpoints of this trial were safety, NY-ESO-1 immune responses, and clinical response. Vaccine-related adverse events observed were fever and injection-site reaction (grade 1). Two patients showed stable disease after vaccination. NY-ESO-1 antibodies were observed in 4 patients at the baseline (sero-positive) and augmented in all patients after vaccination. Eleven patients showed a conversion of negative antibody responses at baseline to positive after vaccination (seroconversion). The seroconversions were observed in all 11 sero-negative patients by the fourth immunization; in particular, it was observed by the second immunization in patients with poly-ICLC, and these induced antibody responses were stronger than those in patients immunized without poly-ICLC. The number of NY-ESO-1-specific interferon (IFN)γ-producing T cells was increased in patients immunized with poly-ICLC and/or OK-432, and furthermore, the increase of IFNγ-producing CD8 T cells in patients immunized with poly-ICLC was significantly higher than that in patients without poly-ICLC. Nonspecific activations of T-cell or antigen presenting cells were not observed. Our present study showed that poly-ICLC is a promising adjuvant for cancer vaccines.

  14. Interdependent TTF1 - ErbB4 interactions are critical for surfactant protein-B homeostasis in primary mouse lung alveolar type II cells.

    PubMed

    Marten, Elger; Nielsen, Heber C; Dammann, Christiane E L

    2015-09-01

    ErbB4 receptor and thyroid transcription factor (TTF)-1 are important modulators of fetal alveolar type II (ATII) cell development and injury. ErbB4 is an upstream regulator of TTF-1, promoting its expression in MLE-12 cells, an ATII cell line. Both proteins are known to promote surfactant protein-B gene (SftpB) and protein (SP-B) expression, but their feedback interactions on each other are not known. We hypothesized that TTF-1 expression has a feedback effect on ErbB4 expression in an in-vitro model of isolated mouse ATII cells. We tested this hypothesis by analyzing the effects of overexpressing HER4 and Nkx2.1, the genes of ErbB4 and TTF-1 on TTF-1 and ErbB4 protein expression, respectively, as well as SP-B protein expression in primary fetal mouse lung ATII cells. Transient ErbB4 protein overexpression upregulated TTF-1 protein expression in primary fetal ATII cells, similarly to results previously shown in MLE-12 cells. Transient TTF-1 protein overexpression down regulated ErbB4 protein expression in both cell types. TTF-1 protein was upregulated in primary transgenic ErbB4-depleted adult ATII cells, however SP-B protein expression in these adult transgenic ATII cells was not affected by the absence of ErbB4. The observation that TTF-1 is upregulated in fetal ATII cells by ErbB4 overexpression and also in ErbB4-deleted adult ATII cells suggests additional factors interact with ErbB4 to regulate TTF-1 levels. We conclude that the interdependency of TTF-1 and ErbB4 is important for surfactant protein levels. The interactive regulation of ErbB4 and TTF-1 needs further elucidation.

  15. Co-vaccination with adeno-associated virus vectors encoding human papillomavirus 16 L1 proteins and adenovirus encoding murine GM-CSF can elicit strong and prolonged neutralizing antibody.

    PubMed

    Liu, Dai-Wei; Chang, Junn-Liang; Tsao, Yeou-Ping; Huang, Chien-Wei; Kuo, Shu-Wen; Chen, Show-Li

    2005-01-01

    Non-infectious human papillomavirus-like particles (VLPs), encoded by the major capsid gene L1, have been shown to be effective as vaccines to prevent cervical cancer. We have developed the genetic immunization of the L1 gene to induce a neutralizing antibody. We constructed and generated a recombinant adeno-associated virus encoding human papillomavirus (HPV) 16 L1 protein that could form virus-like particles in transduced cells. Previous reports have demonstrated that the formation of VLP is necessary to induce high titers of neutralizing antibodies to protect an animal from viral challenge. Therefore, we carried out a single intramuscular (i.m.) injection with recombinant adeno-associated virus encoding HPV-16 L1 protein (rAAV-16L1) in BALB/c mice, which ultimately produced stronger and more prolonged neutralizing L1 antibodies, when compared to the DNA vaccine. Immunohistochemistry showed that the accumulation of antigen presenting cells, such as macrophages and dendritic cells, in rAAV-16L1 and L1 DNA-injected muscle fibers may be due to the L1 protein expression, but not to AAV infection. When compared to the L1 VLP vaccine, however, the titers of neutralizing L1 antibodies induced by VLP were higher than those induced by rAAV-16L1. Co-vaccinating with rAAV-16L1 and adenovirus encoding murine GM-CSF (rAAV-16L1/rAd-mGM-CSF) induced comparable higher levels of neutralizing L1 antibodies with those of VLP. This implies that a single i.m. co-injection with rAAV-16L1/rAd-mGM-CSF can achieve the same vaccine effect as a VLP vaccine requiring 3 booster injections.

  16. Osa Protein Constitutes a Strong Oncogenic Suppression System That Can Block vir-Dependent Transfer of IncQ Plasmids between Agrobacterium Cells and the Establishment of IncQ Plasmids in Plant Cells

    PubMed Central

    Lee, Lan-Ying; Gelvin, Stanton B.

    2004-01-01

    The osa (oncogenic suppressive activity) gene of the IncW group plasmid pSa is sufficient to suppress tumorigenesis by Agrobacterium tumefaciens. osa confers oncogenic suppression by inhibiting VirE2 protein export. This result is similar, but not identical, to that of oncogenic suppression by the IncQ plasmid RSF1010. We conducted a series of experiments to compare oncogenic suppression by these two systems. Agrobacterium strains harboring plasmids containing osa are more able to effect oncogenic suppression than are similar strains containing various RSF1010 derivatives. When osa is present within a donor Agrobacterium strain that also carries a derivative of RSF1010, the transfer of RSF1010 derivatives to recipient bacteria and their establishment in plants are blocked. Oncogenic suppression is still effected when the osa gene is integrated into the Agrobacterium chromosome, suggesting that it is the osa gene product that is active in suppression and that suppression does not require a protein-nucleic acid intermediate like that described for IncQ plasmids. Extracellular complementation experiments with tobacco leaf disks indicated that Osa blocks stable transfer of RSF1010 to plant cells by inhibiting transfer of VirE2, which is essential for the transfer of RSF1010 into plant cells, and not by inhibiting the actual transfer of RSF1010 itself. Our results suggest that Osa and RSF1010 cause oncogenic suppression by using different mechanisms. PMID:15489437

  17. Recent advances of strong-strong beam-beam simulation

    SciTech Connect

    Qiang, Ji; Furman, Miguel A.; Ryne, Robert D.; Fischer, Wolfram; Ohmi,Kazuhito

    2004-09-15

    In this paper, we report on recent advances in strong-strong beam-beam simulation. Numerical methods used in the calculation of the beam-beam forces are reviewed. A new computational method to solve the Poisson equation on nonuniform grid is presented. This method reduces the computational cost by a half compared with the standard FFT based method on uniform grid. It is also more accurate than the standard method for a colliding beam with low transverse aspect ratio. In applications, we present the study of coherent modes with multi-bunch, multi-collision beam-beam interactions at RHIC. We also present the strong-strong simulation of the luminosity evolution at KEKB with and without finite crossing angle.

  18. Effects of strong disorder in strongly correlated superconductors

    NASA Astrophysics Data System (ADS)

    Chakraborty, Debmalya; Sensarma, Rajdeep; Ghosal, Amit

    2017-01-01

    We investigate the effect of strong disorder on a system with strong electronic repulsion. In the absence of disorder, the system has a d-wave superconducting ground state with strong non-BCS features due to its proximity to a Mott insulator. We find that while strong correlations make superconductivity in this system immune to weak disorder, superconductivity is destroyed efficiently when disorder strength is comparable to the effective bandwidth. The suppression of charge motion in regions of strong potential fluctuation leads to the formation of Mott insulating patches, which anchor a larger nonsuperconducting region around them. The system thus breaks into islands of Mott insulating and superconducting regions, with Anderson insulating regions occurring along the boundary of these regions. Thus, electronic correlation and disorder, when both are strong, aid each other in destroying superconductivity, in contrast to their competition at weak disorder. Our results shed light on why zinc impurities are efficient in destroying superconductivity in cuprates, even though it is robust to weaker impurities.

  19. Identification of quantitative trait loci (QTL) for oil and protein contents and their relationships with other seed quality traits in Brassica juncea.

    PubMed

    Mahmood, T; Rahman, M H; Stringam, G R; Yeh, F; Good, A G

    2006-11-01

    A detailed RFLP-genomic map was used to study the genetics of oil, seed and meal protein and sum of oil and seed/meal protein contents in a recombinant doubled-haploid population developed by crossing black- and yellow-seeded Brassica juncea lines. Two yellow seed color genes (SC-B4, SC-A6) and one QTL for erucic acid content (E(1b)) showed pleiotropic effect for oil, protein and sum of oil and seed/meal protein contents. Six (O-A1, O-A6, O-A9, O-B3, O-B4, O-B5) and five (SP-A1, SP-A9, SP-B4, SP-B6, SP-C) QTLs were significant for oil and seed protein contents, respectively. Tight linkage of three of these QTLs (SP-A1, SP-A9, SP-B4, O-A1, O-A9, O-B4), with opposite effects, poses challenge to the plant breeders for simultaneous improvement of negatively correlated (r = -0.7**) oil and seed protein contents. However, one QTL for oil content (O-B3) and two for seed protein content (SP-B6, SP-C) were found to be unlinked, which offer the possibility for simultaneous improvement of these two traits. QTLs significant for meal protein (MP-A1, MP-A6, MP-A9, MP-B5, MP-B6) were significant at least for oil, seed protein or sum of oil and seed/meal protein contents (T-A6, T-A7, T-B4, T-B5). Sum of oil and seed protein contents and sum of oil and meal protein contents had a perfect correlation, as well as same epistatic interactions and QTLs with similar additive effect. This indicates that protein in seed or meal has practically the same meaning for breeding purposes. Epistatic interactions were significant for the quality traits, and their linkage reflected association among the traits.

  20. Titanium: light, strong, and white

    USGS Publications Warehouse

    Woodruff, Laurel; Bedinger, George

    2013-01-01

    Titanium (Ti) is a strong silver-gray metal that is highly resistant to corrosion and is chemically inert. It is as strong as steel but 45 percent lighter, and it is twice as strong as aluminum but only 60 percent heavier. Titanium dioxide (TiO2) has a very high refractive index, which means that it has high light-scattering ability. As a result, TiO2 imparts whiteness, opacity, and brightness to many products. ...Because of the unique physical properties of titanium metal and the whiteness provided by TiO2, titanium is now used widely in modern industrial societies.

  1. Creating and Nurturing Strong Teams.

    ERIC Educational Resources Information Center

    Martin, Kaye M.

    1999-01-01

    Discusses ways to create and sustain strong teaching teams, including matching curriculum goals, complementary professional strengths, and exercise of autonomy. Elaborates the administrator's role in nurturing and supporting teamwork. (JPB)

  2. Cavity quantum electrodynamics: Beyond strong

    NASA Astrophysics Data System (ADS)

    Murch, Kater

    2017-01-01

    When light and matter are strongly coupled, they lose their distinct character and merge into a hybrid state. Three experiments explore this exotic regime using artificial atoms, with promise for quantum technologies.

  3. Simulating strongly correlated electrons with a strongly interacting Fermi gas

    SciTech Connect

    Thomas, John E.

    2013-05-28

    The quantum many-body physics of strongly-correlated fermions is studied in a degenerate, strongly- interacting atomic Fermi gas, first realized by our group with DOE support in 2002. This system, which exhibits strong spin pairing, is now widely studied and provides an important paradigm for testing predictions based on state-of-the-art many-body theory in fields ranging from nuclear matter to high temperature superfluidity and superconductivity. As the system is strongly interacting, both the superfluid and the normal fluid are nontrivial and of great interest. A central part of our program on Fermi gases is the connection between the study of thermodynamics, supported by DOE and the study of hydrodynamic transport, supported by NSF. This connection is especially interesting in view of a recent conjecture from the string theory community on the concept of nearly perfect normal fluids, which exhibit a minimum ratio of shear viscosity to entropy density in strongly-interacting, scale-invariant systems.

  4. Strong Photoassociation in Ultracold Fermions

    NASA Astrophysics Data System (ADS)

    Jing, Li; Jamison, Alan; Rvachov, Timur; Ebadi, Sepher; Son, Hyungmok; Jiang, Yijun; Zwierlein, Martin; Ketterle, Wolfgang

    2016-05-01

    Despite many studies there are still open questions about strong photoassociation in ultracold gases. Photoassociation occurs only at short range and thus can be used as a tool to probe and control the two-body correlation function in an interacting many-body system and to engineer Hamiltonians using dissipation. We propose the possibility to slow down decoherence by photoassociation through the quantum Zeno effect. This can realized by shining strong photoassociation light on the superposition of the lowest two hyperfine states of Lithium 6. NSF, ARO-MURI, Samsung, NSERC.

  5. PREFACE: Strongly Coupled Coulomb Systems Strongly Coupled Coulomb Systems

    NASA Astrophysics Data System (ADS)

    Neilson, David; Senatore, Gaetano

    2009-05-01

    This special issue contains papers presented at the International Conference on Strongly Coupled Coulomb Systems (SCCS), held from 29 July-2 August 2008 at the University of Camerino. Camerino is an ancient hill-top town located in the Apennine mountains of Italy, 200 kilometres northeast of Rome, with a university dating back to 1336. The Camerino conference was the 11th in a series which started in 1977: 1977: Orleans-la-Source, France, as a NATO Advanced Study Institute on Strongly Coupled Plasmas (hosted by Marc Feix and Gabor J Kalman) 1982: Les Houches, France (hosted by Marc Baus and Jean-Pierre Hansen) 1986: Santa Cruz, California, USA (hosted by Forrest J Rogers and Hugh E DeWitt) 1989: Tokyo, Japan (hosted by Setsuo Ichimaru) 1992: Rochester, New York, USA (hosted by Hugh M Van Horn and Setsuo Ichimaru) 1995: Binz, Germany (hosted by Wolf Dietrich Kraeft and Manfred Schlanges) 1997: Boston, Massachusetts, USA (hosted by Gabor J Kalman) 1999: St Malo, France (hosted by Claude Deutsch and Bernard Jancovici) 2002: Santa Fe, New Mexico, USA (hosted by John F Benage and Michael S Murillo) 2005: Moscow, Russia (hosted by Vladimir E Fortov and Vladimir Vorob'ev). The name of the series was changed in 1996 from Strongly Coupled Plasmas to Strongly Coupled Coulomb Systems to reflect a wider range of topics. 'Strongly Coupled Coulomb Systems' encompasses diverse many-body systems and physical conditions. The purpose of the conferences is to provide a regular international forum for the presentation and discussion of research achievements and ideas relating to a variety of plasma, liquid and condensed matter systems that are dominated by strong Coulomb interactions between their constituents. Each meeting has seen an evolution of topics and emphases that have followed new discoveries and new techniques. The field has continued to see new experimental tools and access to new strongly coupled conditions, most recently in the areas of warm matter, dusty plasmas

  6. Galaxies with Strong Nitrogen Lines

    NASA Astrophysics Data System (ADS)

    Bergmann, T. S.; Pastoriza, M. G.

    1987-05-01

    ABSTRACT. From a qualitative spectroscopic survey of southern galaxies made by Pastoriza, a group with different morphological types whose nuclear region showed particular strong emission [N II]A6548-6584 lines when compared to Hn, was selected in order to investigate why [N II] is so strong. This work presents the results of a first analysis of the spectra of some of the galaxies above obtained with the 1-m telescope plus 2DFRUTTI detector of the Cerro Tololo Inter-American Observatory. The spectra are all very similar showing strong stellar continuum and absorption lines, and all the emission spectra show [0111] >[OII], [NIl] > H . None of the spectra show H in emission. Using the relative intensities of the H and K Call lines (Talent 1982, PLtb. A.S.P., 94,36), the obtained integrated spectra for all the observed galaxies is later than GO, which means that the H absorption lines should not be strong. From the relative intensities of the emission lines, we conclude that these galaxies cannot be classified as Starburst or LINERS. They are similar to Seyfert 2 (Osterbrock 1986, Act#va QSO4, preprint), but the FWHM of the lines is less than 300 km s . Also Ol X6300 is not clearly seen, and the absorption spectrum is strong relative to the emission spectrum. The preliminary conclusion is an activity similar but milder than that present in Seyfert 2 galaxies, as sug gested by Rose and Searle (1982, Ap. 5., 253, 556) and Rose and Cecil (1983, Ap. 5., 266, 531) for the nucleus of M51, maybe affected by an anomalous nitrogen abundance. K o : GALAXIES-ACTIVE - SPECTROSCOPY

  7. Quality control by <strong>HyperS>pectral <strong>I>maging (HSI) in solid waste recycling: logics, algorithms and procedures

    NASA Astrophysics Data System (ADS)

    Bonifazi, Giuseppe; Serranti, Silvia

    2014-03-01

    In secondary raw materials and recycling sectors, the products quality represents, more and more, the key issue to pursuit in order to be competitive in a more and more demanding market, where quality standards and products certification play a preheminent role. These goals assume particular importance when recycling actions are applied. Recovered products, resulting from waste materials, and/or dismissed products processing, are, in fact, always seen with a certain suspect. An adequate response of the industry to the market can only be given through the utilization of equipment and procedures ensuring pure, high-quality production, and efficient work and cost. All these goals can be reached adopting not only more efficient equipment and layouts, but also introducing new processing logics able to realize a full control of the handled material flow streams fulfilling, at the same time, i) an easy management of the procedures, ii) an efficient use of the energy, iii) the definition and set up of reliable and robust procedures, iv) the possibility to implement network connectivity capabilities finalized to a remote monitoring and control of the processes and v) a full data storage, analysis and retrieving. Furthermore the ongoing legislation and regulation require the implementation of recycling infrastructure characterised by high resources efficiency and low environmental impacts, both aspects being strongly linked to the waste materials and/or dismissed products original characteristics. For these reasons an optimal recycling infrastructure design primarily requires a full knowledge of the characteristics of the input waste. What previously outlined requires the introduction of a new important concept to apply in solid waste recycling, the recycling-oriented characterization, that is the set of actions addressed to strategically determine selected attributes, in order to get goaloriented data on waste for the development, implementation or improvement of recycling

  8. PREFACE: Strongly correlated electron systems Strongly correlated electron systems

    NASA Astrophysics Data System (ADS)

    Saxena, Siddharth S.; Littlewood, P. B.

    2012-07-01

    This special section is dedicated to the Strongly Correlated Electron Systems Conference (SCES) 2011, which was held from 29 August-3 September 2011, in Cambridge, UK. SCES'2011 is dedicated to 100 years of superconductivity and covers a range of topics in the area of strongly correlated systems. The correlated electronic and magnetic materials featured include f-electron based heavy fermion intermetallics and d-electron based transition metal compounds. The selected papers derived from invited presentations seek to deepen our understanding of the rich physical phenomena that arise from correlation effects. The focus is on quantum phase transitions, non-Fermi liquid phenomena, quantum magnetism, unconventional superconductivity and metal-insulator transitions. Both experimental and theoretical work is presented. Based on fundamental advances in the understanding of electronic materials, much of 20th century materials physics was driven by miniaturisation and integration in the electronics industry to the current generation of nanometre scale devices. The achievements of this industry have brought unprecedented advances to society and well-being, and no doubt there is much further to go—note that this progress is founded on investments and studies in the fundamentals of condensed matter physics from more than 50 years ago. Nevertheless, the defining challenges for the 21st century will lie in the discovery in science, and deployment through engineering, of technologies that can deliver the scale needed to have an impact on the sustainability agenda. Thus the big developments in nanotechnology may lie not in the pursuit of yet smaller transistors, but in the design of new structures that can revolutionise the performance of solar cells, batteries, fuel cells, light-weight structural materials, refrigeration, water purification, etc. The science presented in the papers of this special section also highlights the underlying interest in energy-dense materials, which

  9. Kinetic mixing at strong coupling

    NASA Astrophysics Data System (ADS)

    Del Zotto, Michele; Heckman, Jonathan J.; Kumar, Piyush; Malekian, Arada; Wecht, Brian

    2017-01-01

    A common feature of many string-motivated particle physics models is additional strongly coupled U (1 )'s. In such sectors, electric and magnetic states have comparable mass, and integrating out modes also charged under U (1 ) hypercharge generically yields C P preserving electric kinetic mixing and C P violating magnetic kinetic mixing terms. Even though these extra sectors are strongly coupled, we show that in the limit where the extra sector has approximate N =2 supersymmetry, we can use formal methods from Seiberg-Witten theory to compute these couplings. We also calculate various quantities of phenomenological interest such as the cross section for scattering between visible sector states and heavy extra sector states as well as the effects of supersymmetry breaking induced from coupling to the minimal supersymmetric Standard Model.

  10. Topics in strong Langmuir turbulence

    NASA Technical Reports Server (NTRS)

    Nicholson, D. R.

    1983-01-01

    Progress in two approaches to the study of strong Langmuir turbulence is reported. In two spatial dimensions, numerical solution of the Zakharov equations yields a steady state involving linear growth, linear damping, and a collection of coherent, long-lived entities which might loosely be called solitons. In one spatial dimension, a statistical theory is applied to the cubically nonlinear Schroedinger equation and is solved analytically in a special case.

  11. Topics in strong Langmuir turbulence

    NASA Technical Reports Server (NTRS)

    Nicholson, D. R.

    1982-01-01

    Progress in two approaches to the study of strong Langmuir turbulence is reported. In two spatial dimensions, numerical solution of the Zakharov equations yields a steady state involving linear growth, linear damping, and a collection of coherent, long-lived entities which might loosely be called solitons. In one spatial dimension, a statistical theory is applied to the cubically nonlinear Schroedinger equation and is solved analytically in a special case.

  12. Flavour democracy in strong unification

    NASA Astrophysics Data System (ADS)

    Abel, S. A.; King, S. F.

    1998-09-01

    We show that the fermion mass spectrum may naturally be understood in terms of flavour democratic fixed points in supersymmetric theories which have a large domain of attraction in the presence of ``strong unification''. Our approach provides an alternative to the approximate Yukawa texture zeroes of the Froggatt-Nielsen mechanism. We discuss a particular model based on a broken gauged SU(3)LxSU(3)R family symmetry which illustrates our approach.

  13. Strongly interacting parton matter equilibration

    SciTech Connect

    Ozvenchuk, V.; Linnyk, O.; Bratkovskaya, E.; Gorenstein, M.; Cassing, W.

    2012-07-15

    We study the kinetic and chemical equilibration in 'infinite' parton matter within the Parton-Hadron-String Dynamics transport approach. The 'infinite' matter is simulated within a cubic box with periodic boundary conditions initialized at different energy densities. Particle abundances, kinetic energy distributions, and the detailed balance of the off-shell quarks and gluons in the strongly-interacting quarkgluon plasma are addressed and discussed.

  14. Tilts in strong ground motion

    USGS Publications Warehouse

    Graizer, V.

    2006-01-01

    Most instruments used in seismological practice to record ground motion are pendulum seismographs, velocigraphs, or accelerographs. In most cases it is assumed that seismic instruments are only sensitive to the translational motion of the instrument's base. In this study the full equation of pendulum motion, including the inputs of rotations and tilts, is considered. It is shown that tilting the accelerograph's base can severely impact its response to the ground motion. The method of tilt evaluation using uncorrected strong-motion accelerograms was first suggested by Graizer (1989), and later tested in several laboratory experiments with different strong-motion instruments. The method is based on the difference in the tilt sensitivity of the horizontal and vertical pendulums. The method was applied to many of the strongest records of the Mw 6.7 Northridge earthquake of 1994. Examples are shown when relatively large tilts of up to a few degrees occurred during strong earthquake ground motion. Residual tilt extracted from the strong-motion record at the Pacoima Dam-Upper Left Abutment reached 3.1?? in N45??E direction, and was a result of local earthquake-induced tilting due to high-amplitude shaking. This value is in agreement with the residual tilt measured by using electronic level a few days after the earthquake. The method was applied to the building records from the Northridge earthquake. According to the estimates, residual tilt reached 2.6?? on the ground floor of the 12-story Hotel in Ventura. Processing of most of the strongest records of the Northridge earthquake shows that tilts, if happened, were within the error of the method, or less than about 0.5??.

  15. Strongly interacting parton matter equilibration

    NASA Astrophysics Data System (ADS)

    Ozvenchuk, V.; Linnyk, O.; Bratkovskaya, E.; Gorenstein, M.; Cassing, W.

    2012-07-01

    We study the kinetic and chemical equilibration in "infinite" parton matter within the Parton-Hadron-String Dynamics transport approach. The "infinite" matter is simulated within a cubic box with periodic boundary conditions initialized at different energy densities. Particle abundances, kinetic energy distributions, and the detailed balance of the off-shell quarks and gluons in the strongly-interacting quarkgluon plasma are addressed and discussed.

  16. Strongly magnetized classical plasma models

    NASA Technical Reports Server (NTRS)

    Montgomery, D.; Peyraud, J.; Dewitt, C.

    1974-01-01

    Discrete particle processes in the presence of a strong external magnetic field were investigated. These processes include equations of state and other equilibrium thermodynamic relations, thermal relaxation phenomena, transport properties, and microscopic statistical fluctuations in such quantities as the electric field and the charge density. Results from the equilibrium statistical mechanics of two-dimensional plasmas are discussed, along with nonequilibrium statistical mechanics of the electrostatic guiding-center plasma (a two-dimensional plasma model).

  17. Disordered strongly correlated electronic systems

    NASA Astrophysics Data System (ADS)

    Javan Mard, Hossein

    Disorder can have a vast variety of consequences for the physics of phase transitions. Some transitions remain unchanged in the presence of disorder while others are completely destroyed. In this dissertation we study the effects of quenched disorder on electronic systmens at zero temperature. First, we perform variational studies of the interaction-localization problem to describe the interaction-induced renormalizations of the effective (screened) random potential seen by quasiparticles. Here we present results of careful finite-size scaling studies for the conductance of disordered Hubbard chains at half-filling and zero temperature. While our results indicate that quasiparticle wave functions remain exponentially localized even in the presence of moderate to strong repulsive interactions, we show that interactions produce a strong decrease of the characteristic conductance scale g* signaling the crossover to strong localization. This effect, which cannot be captured by a simple renormalization of the disorder strength, instead reflects a peculiar non-Gaussian form of the spatial correlations of the screened disordered potential, a hitherto neglected mechanism to dramatically reduce the impact of Anderson localization (interference) effects. Second, we formulate a strong-disorder renormalization-group (SDRG) approach to study the beta function of the tight-binding model in one dimension with both diagonal and off-diagonal disorder for states at the band center. We show that the SDRG method, when used to compute transport properties, yields exact results since it is identical to the transfer matrix method. The beta function is shown to be universal when only off-diagonal disorder is present even though single-parameter scaling is known to be violated. A different single-parameter scaling theory is formulated for this particular (particle-hole symmetric) case. Upon breaking particle-hole symmetry (by adding diagonal disorder), the beta function is shown to

  18. Strong interactive massive particles from a strong coupled theory

    SciTech Connect

    Khlopov, Maxim Yu.; Kouvaris, Chris

    2008-03-15

    Minimal walking technicolor models can provide a nontrivial solution for cosmological dark matter, if the lightest technibaryon is doubly charged. Technibaryon asymmetry generated in the early Universe is related to baryon asymmetry, and it is possible to create an excess of techniparticles with charge (-2). These excessive techniparticles are all captured by {sup 4}He, creating techni-O-helium tOHe atoms, as soon as {sup 4}He is formed in big bang nucleosynthesis. The interaction of techni-O-helium with nuclei opens new paths to the creation of heavy nuclei in big bang nucleosynthesis. Because of the large mass of technibaryons, the tOHe ''atomic'' gas decouples from the baryonic matter and plays the role of dark matter in large scale structure formation, while structures in small scales are suppressed. Nuclear interactions with matter slow down cosmic techni-O-helium in the Earth below the threshold of underground dark matter detectors, thus escaping severe cryogenic dark matter search constraints. On the other hand, these nuclear interactions are not sufficiently strong to exclude this form of strongly interactive massive particles by constraints from the XQC experiment. Experimental tests of this hypothesis are possible in the search for tOHe in balloon-borne experiments (or on the ground) and for its charged techniparticle constituents in cosmic rays and accelerators. The tOHe atoms can cause cold nuclear transformations in matter and might form anomalous isotopes, offering possible ways to exclude (or prove?) their existence.

  19. PREFACE: Strongly Coupled Coulomb Systems

    NASA Astrophysics Data System (ADS)

    Fortov, Vladimir E.; Golden, Kenneth I.; Norman, Genri E.

    2006-04-01

    This special issue contains papers presented at the International Conference on Strongly Coupled Coulomb Systems (SCCS) which was held during the week of 20 24 June 2005 in Moscow, Russia. The Moscow conference was the tenth in a series of conferences. The previous conferences were organized as follows. 1977: Orleans-la-Source, France, as a NATO Advanced Study Institute on Strongly Coupled Plasmas (organized by Marc Feix and Gabor J Kalman) 1982: Les Houches, France (organized by Marc Baus and Jean-Pierre Hansen) 1986: Santa Cruz, California, USA (hosted by Forrest J Rogers and Hugh E DeWitt) 1989: Tokyo, Japan (hosted by Setsuo Ichimaru) 1992: Rochester, NY, USA (hosted by Hugh M Van Horn and Setsuo Ichimaru) 1995: Binz, Germany (hosted by Wolf Dietrich Kraeft and Manfred Schlanges) 1997: Boston, Massachusetts, USA (hosted by Gabor J Kalman) 1999: St Malo, France (hosted by Claude Deutsch and Bernard Jancovici) 2002: Santa Fe, New Mexico, USA (hosted by John F Benage and Michael S Murillo) After 1995 the name of the series was changed from `Strongly Coupled Plasmas' to the present name in order to extend the topics of the conferences. The planned frequency for the future is once every three years. The purpose of these conferences is to provide an international forum for the presentation and discussion of research accomplishments and ideas relating to a variety of plasma liquid and condensed matter systems, dominated by strong Coulomb interactions between their constituents. Strongly coupled Coulomb systems encompass diverse many-body systems and physical conditions. Each meeting has seen an evolution of topics and emphasis as new discoveries and new methods appear. This year, sessions were organized for invited presentations and posters on dense plasmas and warm matter, astrophysics and dense hydrogen, non-neutral and ultracold plasmas, dusty plasmas, condensed matter 2D and layered charged-particle systems, Coulomb liquids, and statistical theory of SCCS. Within

  20. Dynamics of strongly correlated and strongly inhomogeneous plasmas.

    PubMed

    Kählert, Hanno; Kalman, Gabor J; Bonitz, Michael

    2014-07-01

    Kinetic and fluid equations are derived for the dynamics of classical inhomogeneous trapped plasmas in the strong coupling regime. The starting point is an extended Singwi-Tosi-Land-Sjölander (STLS) ansatz for the dynamic correlation function, which is allowed to depend on time and both particle coordinates separately. The time evolution of the correlation function is determined from the second equation of the Bogolyubov-Born-Green-Kirkwood-Yvon hierarchy. We study the equations in the linear limit and derive a nonlocal equation for the fluid displacement field. Comparisons to first-principles molecular dynamics simulations reveal an excellent quality of our approach thereby overcoming the limitations of the broadly used STLS scheme.

  1. Numerical micromagnetism of strong inhomogeneities

    NASA Astrophysics Data System (ADS)

    Andreas, Christian; Gliga, Sebastian; Hertel, Riccardo

    2014-08-01

    The size of micromagnetic structures, such as domain walls or vortices, is comparable to the exchange length of the ferromagnet. Both, the exchange length of the stray field ls and the magnetocrystalline exchange length lk, are material-dependent quantities that usually lie in the nanometer range. This emphasizes the theoretical challenges associated with the mesoscopic nature of micromagnetism: the magnetic structures are much larger than the atomic lattice constant, but at the same time much smaller than the sample size. In computer simulations, the smallest exchange length serves as an estimate for the largest cell size admissible to prevent appreciable discretization errors. This general rule is not valid in special situations where the magnetization becomes particularly inhomogeneous. When such strongly inhomogeneous structures develop, micromagnetic simulations inevitably contain systematic and numerical errors. It is suggested to combine micromagnetic theory with a Heisenberg model to resolve such problems. We analyze cases where strongly inhomogeneous structures pose limits to standard micromagnetic simulations, arising from fundamental aspects as well as from numerical drawbacks.

  2. Strong dynamics at the LHC

    NASA Astrophysics Data System (ADS)

    Ittisamai, Pawin

    The limitations of the Standard Model of particle physics, despite its being a well-established theory, have prompted various proposals for new physics capable of addressing its shortcomings. The particular issue to be explored here is the mechanism of electroweak symmetry breaking, the probing of which lies within the TeV-scale physics accessible to the Large Hadron Collider (LHC). This thesis focuses on the phenomenology of a class of models featuring a dynamical breaking of the electroweak symmetry via strong dynamics. Consequences of recent experiments and aspects of near-future experiments are presented. We study the implications of the LHC Higgs searches available at the time the related journal article was written for technicolor models that feature colored technifermions. Then we discuss the properties of a technicolor model featuring strong-top dynamics that is viable for explaining the recently discovered boson of mass 126 GeV. We introduce a novel method of characterizing the color structure of a new massive vector boson, often predicted in various new physics models, using information that will be promptly available if it is discovered in the near-future experiments at the LHC. We generalize the idea for more realistic models where a vector boson has flavor non-universal couplings to quarks. Finally, we discuss the possibilities of probing the chiral structure of a new color-octet vector boson.

  3. Strong-Coupling Superconductivity. I

    NASA Astrophysics Data System (ADS)

    Scalapino, D. J.; Schrieffer, J. R.; Wilkins, J. W.

    The pairing theory of superconductivity is extended to treat systems having strong electron-phonon coupling. In this regime the Landau quasiparticle approximation is invalid. In the theory we treat phonon and Coulomb interactions on the same basis and carry out the analysis using the nonzero-temperature Green's functions of the Nambu formalism. The generalized energy-gap equation thus obtained is solved (at T = 0°K) for a model which closely represents lead and the complex energy-gap parameter Δ(ω)) is plotted as a function of energy for several choices of phonon and Coulomb interaction strengths. An expression for the single-particle tunneling density of states is derived, which, when combined with Δ(ω), gives excellent agreement with experiment, if the phonon interaction strength is chosen to give the observed energy gap Δ0 at zero temperature. The tunneling experiments therefore give a detailed justification of the phonon mechanism of superconductivity and of the validity of the strong-coupling theory. In addition, by combining theory and the tunneling experiments, much can be learned about the electron-phon interaction and the phonon density of states. The theory is accurate to terms of order the square root of the electron-ion mass ratio, 10-2-10-3.

  4. EDITORIAL: Strongly correlated electron systems Strongly correlated electron systems

    NASA Astrophysics Data System (ADS)

    Ronning, Filip; Batista, Cristian

    2011-03-01

    Strongly correlated electrons is an exciting and diverse field in condensed matter physics. This special issue aims to capture some of that excitement and recent developments in the field. Given that this issue was inspired by the 2010 International Conference on Strongly Correlated Electron Systems (SCES 2010), we briefly give some history in order to place this issue in context. The 2010 International Conference on Strongly Correlated Electron Systems was held in Santa Fe, New Mexico, a reunion of sorts from the 1989 International Conference on the Physics of Highly Correlated Electron Systems that also convened in Santa Fe. SCES 2010—co-chaired by John Sarrao and Joe Thompson—followed the tradition of earlier conferences, in this century, hosted by Buzios (2008), Houston (2007), Vienna (2005), Karlsruhe (2004), Krakow (2002) and Ann Arbor (2001). Every three years since 1997, SCES has joined the International Conference on Magnetism (ICM), held in Recife (2000), Rome (2003), Kyoto (2006) and Karlsruhe (2009). Like its predecessors, SCES 2010 topics included strongly correlated f- and d-electron systems, heavy-fermion behaviors, quantum-phase transitions, non-Fermi liquid phenomena, unconventional superconductivity, and emergent states that arise from electronic correlations. Recent developments from studies of quantum magnetism and cold atoms complemented the traditional subjects and were included in SCES 2010. 2010 celebrated the 400th anniversary of Santa Fe as well as the birth of astronomy. So what's the connection to SCES? The Dutch invention of the first practical telescope and its use by Galileo in 1610 and subsequent years overturned dogma that the sun revolved about the earth. This revolutionary, and at the time heretical, conclusion required innovative combinations of new instrumentation, observation and mathematics. These same combinations are just as important 400 years later and are the foundation of scientific discoveries that were discussed

  5. An engineered strong promoter for streptomycetes.

    PubMed

    Wang, Weishan; Li, Xiao; Wang, Juan; Xiang, Sihai; Feng, Xiaozhou; Yang, Keqian

    2013-07-01

    Well-characterized promoters are essential tools for metabolic engineering and synthetic biology. In Streptomyces coelicolor, the native kasOp is a temporally expressed promoter strictly controlled by two regulators, ScbR and ScbR2. In this work, first, kasOp was engineered to remove a common binding site of ScbR and ScbR2 upstream of its core region, thus generating a stronger promoter, kasOp3. Second, another ScbR binding site internal to the kasOp3 core promoter region was abolished by random mutation and screening of the mutant library to obtain the strongest promoter, kasOp* (where the asterisk is used to distinguish the engineered promoter from the native promoter). The activities of kasOp* were compared with those of two known strong promoters, ermEp* and SF14p, in three Streptomyces species. kasOp* showed the highest activity at the transcription and protein levels in all three hosts. Furthermore, relative to ermEp* and SF14p, kasOp* was shown to confer the highest actinorhodin production level when used to drive the expression of actII-ORF4 in S. coelicolor. Therefore, kasOp* is a simple and well-defined strong promoter useful for gene overexpression in streptomycetes.

  6. A metafluid exhibiting strong optical magnetism.

    PubMed

    Sheikholeslami, Sassan N; Alaeian, Hadiseh; Koh, Ai Leen; Dionne, Jennifer A

    2013-09-11

    Advances in the field of metamaterials have enabled unprecedented control of light-matter interactions. Metamaterial constituents support high-frequency electric and magnetic dipoles, which can be used as building blocks for new materials capable of negative refraction, electromagnetic cloaking, strong visible-frequency circular dichroism, and enhancing magnetic or chiral transitions in ions and molecules. While all metamaterials to date have existed in the solid-state, considerable interest has emerged in designing a colloidal metamaterial or "metafluid". Such metafluids would combine the advantages of solution-based processing with facile integration into conventional optical components. Here we demonstrate the colloidal synthesis of an isotropic metafluid that exhibits a strong magnetic response at visible frequencies. Protein-antibody interactions are used to direct the solution-phase self-assembly of discrete metamolecules comprised of silver nanoparticles tightly packed around a single dielectric core. The electric and magnetic response of individual metamolecules and the bulk metamaterial solution are directly probed with optical scattering and spectroscopy. Effective medium calculations indicate that the bulk metamaterial exhibits a negative effective permeability and a negative refractive index at modest fill factors. This metafluid can be synthesized in large-quantity and high-quality and may accelerate development of advanced nanophotonic and metamaterial devices.

  7. An Engineered Strong Promoter for Streptomycetes

    PubMed Central

    Wang, Weishan; Li, Xiao; Wang, Juan; Xiang, Sihai; Feng, Xiaozhou

    2013-01-01

    Well-characterized promoters are essential tools for metabolic engineering and synthetic biology. In Streptomyces coelicolor, the native kasOp is a temporally expressed promoter strictly controlled by two regulators, ScbR and ScbR2. In this work, first, kasOp was engineered to remove a common binding site of ScbR and ScbR2 upstream of its core region, thus generating a stronger promoter, kasOp3. Second, another ScbR binding site internal to the kasOp3 core promoter region was abolished by random mutation and screening of the mutant library to obtain the strongest promoter, kasOp* (where the asterisk is used to distinguish the engineered promoter from the native promoter). The activities of kasOp* were compared with those of two known strong promoters, ermEp* and SF14p, in three Streptomyces species. kasOp* showed the highest activity at the transcription and protein levels in all three hosts. Furthermore, relative to ermEp* and SF14p, kasOp* was shown to confer the highest actinorhodin production level when used to drive the expression of actII-ORF4 in S. coelicolor. Therefore, kasOp* is a simple and well-defined strong promoter useful for gene overexpression in streptomycetes. PMID:23686264

  8. Electrophoresis in strong electric fields.

    PubMed

    Barany, Sandor

    2009-01-01

    Two kinds of non-linear electrophoresis (ef) that can be detected in strong electric fields (several hundred V/cm) are considered. The first ("classical" non-linear ef) is due to the interaction of the outer field with field-induced ionic charges in the electric double layer (EDL) under conditions, when field-induced variations of electrolyte concentration remain to be small comparatively to its equilibrium value. According to the Shilov theory, the non-linear component of the electrophoretic velocity for dielectric particles is proportional to the cubic power of the applied field strength (cubic electrophoresis) and to the second power of the particles radius; it is independent of the zeta-potential but is determined by the surface conductivity of particles. The second one, the so-called "superfast electrophoresis" is connected with the interaction of a strong outer field with a secondary diffuse layer of counterions (space charge) that is induced outside the primary (classical) diffuse EDL by the external field itself because of concentration polarization. The Dukhin-Mishchuk theory of "superfast electrophoresis" predicts quadratic dependence of the electrophoretic velocity of unipolar (ionically or electronically) conducting particles on the external field gradient and linear dependence on the particle's size in strong electric fields. These are in sharp contrast to the laws of classical electrophoresis (no dependence of V(ef) on the particle's size and linear dependence on the electric field gradient). A new method to measure the ef velocity of particles in strong electric fields is developed that is based on separation of the effects of sedimentation and electrophoresis using videoimaging and a new flowcell and use of short electric pulses. To test the "classical" non-linear electrophoresis, we have measured the ef velocity of non-conducting polystyrene, aluminium-oxide and (semiconductor) graphite particles as well as Saccharomice cerevisiae yeast cells as a

  9. Strong Winds over the Keel

    NASA Astrophysics Data System (ADS)

    2009-02-01

    The latest ESO image reveals amazing detail in the intricate structures of one of the largest and brightest nebulae in the sky, the Carina Nebula (NGC 3372), where strong winds and powerful radiation from an armada of massive stars are creating havoc in the large cloud of dust and gas from which the stars were born. ESO PR Photo 05a/09 The Carina Nebula ESO PR Video 05a/09 Pan over the Carina Nebula ESO PR Video 05b/09 Carina Nebula Zoom-in The large and beautiful image displays the full variety of this impressive skyscape, spattered with clusters of young stars, large nebulae of dust and gas, dust pillars, globules, and adorned by one of the Universe's most impressive binary stars. It was produced by combining exposures through six different filters from the Wide Field Imager (WFI), attached to the 2.2 m ESO/MPG telescope at ESO's La Silla Observatory, in Chile. The Carina Nebula is located about 7500 light-years away in the constellation of the same name (Carina; the Keel). Spanning about 100 light-years, it is four times larger than the famous Orion Nebula and far brighter. It is an intensive star-forming region with dark lanes of cool dust splitting up the glowing nebula gas that surrounds its many clusters of stars. The glow of the Carina Nebula comes mainly from hot hydrogen basking in the strong radiation of monster baby stars. The interaction between the hydrogen and the ultraviolet light results in its characteristic red and purple colour. The immense nebula contains over a dozen stars with at least 50 to 100 times the mass of our Sun. Such stars have a very short lifespan, a few million years at most, the blink of an eye compared with the Sun's expected lifetime of ten billion years. One of the Universe's most impressive stars, Eta Carinae, is found in the nebula. It is one of the most massive stars in our Milky Way, over 100 times the mass of the Sun and about four million times brighter, making it the most luminous star known. Eta Carinae is highly

  10. Acidic pH triggers conformational changes at the NH2-terminal propeptide of the precursor of pulmonary surfactant protein B to form a coiled coil structure.

    PubMed

    Bañares-Hidalgo, A; Pérez-Gil, J; Estrada, P

    2014-07-01

    Pulmonary surfactant protein SP-B is synthesized as a larger precursor, proSP-B. We report that a recombinant form of human SP-BN forms a coiled coil structure at acidic pH. The protonation of a residue with pK=4.8±0.06 is the responsible of conformational changes detected by circular dichroism and intrinsic fluorescence emission. Sedimentation velocity analysis showed protein oligomerisation at any pH condition, with an enrichment of the species compatible with a tetramer at acidic pH. Low 2,2,2,-trifluoroethanol concentration promoted β-sheet structures in SP-BN, which bind Thioflavin T, at acidic pH, whereas it promoted coiled coil structures at neutral pH. The amino acid stretch predicted to form β-sheet parallel association in SP-BN overlaps with the sequence predicted by several programs to form coiled coil structure. A synthetic peptide ((60)W-E(85)) designed from the sequence of the amino acid stretch of SP-BN predicted to form coiled coil structure showed random coil conformation at neutral pH but concentration-dependent helical structure at acidic pH. Sedimentation velocity analysis of the peptide indicated monomeric state at neutral pH (s20, w=0.55S; Mr~3kDa) and peptide association (s20, w=1.735S; Mr=~14kDa) at acidic pH, with sedimentation equilibrium fitting to a Monomer-Nmer-Mmer model with N=6 and M=4 (Mr=14692Da). We propose that protein oligomerisation through coiled-coil motifs could then be a general feature in the assembly of functional units in saposin-like proteins in general and in the organization of SP-B in a functional surfactant, in particular.

  11. Strongly correlated perovskite fuel cells

    NASA Astrophysics Data System (ADS)

    Zhou, You; Guan, Xiaofei; Zhou, Hua; Ramadoss, Koushik; Adam, Suhare; Liu, Huajun; Lee, Sungsik; Shi, Jian; Tsuchiya, Masaru; Fong, Dillon D.; Ramanathan, Shriram

    2016-06-01

    Fuel cells convert chemical energy directly into electrical energy with high efficiencies and environmental benefits, as compared with traditional heat engines. Yttria-stabilized zirconia is perhaps the material with the most potential as an electrolyte in solid oxide fuel cells (SOFCs), owing to its stability and near-unity ionic transference number. Although there exist materials with superior ionic conductivity, they are often limited by their ability to suppress electronic leakage when exposed to the reducing environment at the fuel interface. Such electronic leakage reduces fuel cell power output and the associated chemo-mechanical stresses can also lead to catastrophic fracture of electrolyte membranes. Here we depart from traditional electrolyte design that relies on cation substitution to sustain ionic conduction. Instead, we use a perovskite nickelate as an electrolyte with high initial ionic and electronic conductivity. Since many such oxides are also correlated electron systems, we can suppress the electronic conduction through a filling-controlled Mott transition induced by spontaneous hydrogen incorporation. Using such a nickelate as the electrolyte in free-standing membrane geometry, we demonstrate a low-temperature micro-fabricated SOFC with high performance. The ionic conductivity of the nickelate perovskite is comparable to the best-performing solid electrolytes in the same temperature range, with a very low activation energy. The results present a design strategy for high-performance materials exhibiting emergent properties arising from strong electron correlations.

  12. Strongly correlated perovskite fuel cells

    SciTech Connect

    Zhou, You; Guan, Xiaofei; Zhou, Hua; Ramadoss, Koushik; Adam, Suhare; Liu, Huajun; Lee, Sungsik; Shi, Jian; Tsuchiya, Masaru; Fong, Dillon D.; Ramanathan, Shriram

    2016-05-16

    Fuel cells convert chemical energy directly into electrical energy with high efficiencies and environmental benefits, as compared with traditional heat engines1, 2, 3, 4. Yttria-stabilized zirconia is perhaps the material with the most potential as an electrolyte in solid oxide fuel cells (SOFCs), owing to its stability and near-unity ionic transference number5. Although there exist materials with superior ionic conductivity, they are often limited by their ability to suppress electronic leakage when exposed to the reducing environment at the fuel interface. Such electronic leakage reduces fuel cell power output and the associated chemo-mechanical stresses can also lead to catastrophic fracture of electrolyte membranes6. Here we depart from traditional electrolyte design that relies on cation substitution to sustain ionic conduction. Instead, we use a perovskite nickelate as an electrolyte with high initial ionic and electronic conductivity. Since many such oxides are also correlated electron systems, we can suppress the electronic conduction through a filling-controlled Mott transition induced by spontaneous hydrogen incorporation. Using such a nickelate as the electrolyte in free-standing membrane geometry, we demonstrate a low-temperature micro-fabricated SOFC with high performance. The ionic conductivity of the nickelate perovskite is comparable to the best-performing solid electrolytes in the same temperature range, with a very low activation energy. The results present a design strategy for high-performance materials exhibiting emergent properties arising from strong electron correlations.

  13. Strongly correlated perovskite fuel cells.

    PubMed

    Zhou, You; Guan, Xiaofei; Zhou, Hua; Ramadoss, Koushik; Adam, Suhare; Liu, Huajun; Lee, Sungsik; Shi, Jian; Tsuchiya, Masaru; Fong, Dillon D; Ramanathan, Shriram

    2016-06-09

    Fuel cells convert chemical energy directly into electrical energy with high efficiencies and environmental benefits, as compared with traditional heat engines. Yttria-stabilized zirconia is perhaps the material with the most potential as an electrolyte in solid oxide fuel cells (SOFCs), owing to its stability and near-unity ionic transference number. Although there exist materials with superior ionic conductivity, they are often limited by their ability to suppress electronic leakage when exposed to the reducing environment at the fuel interface. Such electronic leakage reduces fuel cell power output and the associated chemo-mechanical stresses can also lead to catastrophic fracture of electrolyte membranes. Here we depart from traditional electrolyte design that relies on cation substitution to sustain ionic conduction. Instead, we use a perovskite nickelate as an electrolyte with high initial ionic and electronic conductivity. Since many such oxides are also correlated electron systems, we can suppress the electronic conduction through a filling-controlled Mott transition induced by spontaneous hydrogen incorporation. Using such a nickelate as the electrolyte in free-standing membrane geometry, we demonstrate a low-temperature micro-fabricated SOFC with high performance. The ionic conductivity of the nickelate perovskite is comparable to the best-performing solid electrolytes in the same temperature range, with a very low activation energy. The results present a design strategy for high-performance materials exhibiting emergent properties arising from strong electron correlations.

  14. Promoting Strong Written Communication Skills

    NASA Astrophysics Data System (ADS)

    Narayanan, M.

    2015-12-01

    The reason that an improvement in the quality of technical writing is still needed in the classroom is due to the fact that universities are facing challenging problems not only on the technological front but also on the socio-economic front. The universities are actively responding to the changes that are taking place in the global consumer marketplace. Obviously, there are numerous benefits of promoting strong written communication skills. They can be summarized into the following six categories. First, and perhaps the most important: The University achieves learner satisfaction. The learner has documented verbally, that the necessary knowledge has been successfully acquired. This results in learner loyalty that in turn will attract more qualified learners.Second, quality communication lowers the cost per pupil, consequently resulting in increased productivity backed by a stronger economic structure and forecast. Third, quality communications help to improve the cash flow and cash reserves of the university. Fourth, having high quality communication enables the university to justify the need for high costs of tuition and fees. Fifth, better quality in written communication skills result in attracting top-quality learners. This will lead to happier and satisfied learners, not to mention greater prosperity for the university as a whole. Sixth, quality written communication skills result in reduced complaints, thus meaning fewer hours spent on answering or correcting the situation. The University faculty and staff are thus able to devote more time on scholarly activities, meaningful research and productive community service. References Boyer, Ernest L. (1990). Scholarship reconsidered: Priorities of the Professorate.Princeton, NJ: Carnegie Foundation for the Advancement of Teaching. Hawkins, P., & Winter, J. (1997). Mastering change: Learning the lessons of the enterprise.London: Department for Education and Employment. Buzzel, Robert D., and Bradley T. Gale. (1987

  15. The strong maximum principle revisited

    NASA Astrophysics Data System (ADS)

    Pucci, Patrizia; Serrin, James

    In this paper we first present the classical maximum principle due to E. Hopf, together with an extended commentary and discussion of Hopf's paper. We emphasize the comparison technique invented by Hopf to prove this principle, which has since become a main mathematical tool for the study of second order elliptic partial differential equations and has generated an enormous number of important applications. While Hopf's principle is generally understood to apply to linear equations, it is in fact also crucial in nonlinear theories, such as those under consideration here. In particular, we shall treat and discuss recent generalizations of the strong maximum principle, and also the compact support principle, for the case of singular quasilinear elliptic differential inequalities, under generally weak assumptions on the quasilinear operators and the nonlinearities involved. Our principal interest is in necessary and sufficient conditions for the validity of both principles; in exposing and simplifying earlier proofs of corresponding results; and in extending the conclusions to wider classes of singular operators than previously considered. The results have unexpected ramifications for other problems, as will develop from the exposition, e.g. two point boundary value problems for singular quasilinear ordinary differential equations (Sections 3 and 4); the exterior Dirichlet boundary value problem (Section 5); the existence of dead cores and compact support solutions, i.e. dead cores at infinity (Section 7); Euler-Lagrange inequalities on a Riemannian manifold (Section 9); comparison and uniqueness theorems for solutions of singular quasilinear differential inequalities (Section 10). The case of p-regular elliptic inequalities is briefly considered in Section 11.

  16. Surfactant proteins, SP-A and SP-D, in respiratory fungal infections: their role in the inflammatory response.

    PubMed

    Carreto-Binaghi, Laura Elena; Aliouat, El Moukhtar; Taylor, Maria Lucia

    2016-06-01

    Pulmonary surfactant is a complex fluid that comprises phospholipids and four proteins (SP-A, SP-B, SP-C, and SP-D) with different biological functions. SP-B, SP-C, and SP-D are essential for the lungs' surface tension function and for the organization, stability and metabolism of lung parenchyma. SP-A and SP-D, which are also known as pulmonary collectins, have an important function in the host's lung immune response; they act as opsonins for different pathogens via a C-terminal carbohydrate recognition domain and enhance the attachment to phagocytic cells or show their own microbicidal activity by increasing the cellular membrane permeability. Interactions between the pulmonary collectins and bacteria or viruses have been extensively studied, but this is not the same for fungal pathogens. SP-A and SP-D bind glucan and mannose residues from fungal cell wall, but there is still a lack of information on their binding to other fungal carbohydrate residues. In addition, both their relation with immune cells for the clearance of these pathogens and the role of surfactant proteins' regulation during respiratory fungal infections remain unknown. Here we highlight the relevant findings associated with SP-A and SP-D in those respiratory mycoses where the fungal infective propagules reach the lungs by the airways.

  17. 78 FR 15710 - Strong Sensitizer Guidance

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-12

    ... document is intended to clarify the ``strong sensitizer'' definition, assist manufacturers in understanding... definition of ``strong sensitizer'' found at 16 CFR 1500.3(c)(5). The Commission is proposing to revise the supplemental definition of ``strong sensitizer'' due to advancements in the science of sensitization that...

  18. Quantum dynamics in strong fluctuating fields

    NASA Astrophysics Data System (ADS)

    Goychuk, Igor; Hänggi, Peter

    A large number of multifaceted quantum transport processes in molecular systems and physical nanosystems, such as e.g. nonadiabatic electron transfer in proteins, can be treated in terms of quantum relaxation processes which couple to one or several fluctuating environments. A thermal equilibrium environment can conveniently be modelled by a thermal bath of harmonic oscillators. An archetype situation provides a two-state dissipative quantum dynamics, commonly known under the label of a spin-boson dynamics. An interesting and nontrivial physical situation emerges, however, when the quantum dynamics evolves far away from thermal equilibrium. This occurs, for example, when a charge transferring medium possesses nonequilibrium degrees of freedom, or when a strong time-dependent control field is applied externally. Accordingly, certain parameters of underlying quantum subsystem acquire stochastic character. This may occur, for example, for the tunnelling coupling between the donor and acceptor states of the transferring electron, or for the corresponding energy difference between electronic states which assume via the coupling to the fluctuating environment an explicit stochastic or deterministic time-dependence. Here, we review the general theoretical framework which is based on the method of projector operators, yielding the quantum master equations for systems that are exposed to strong external fields. This allows one to investigate on a common basis, the influence of nonequilibrium fluctuations and periodic electrical fields on those already mentioned dynamics and related quantum transport processes. Most importantly, such strong fluctuating fields induce a whole variety of nonlinear and nonequilibrium phenomena. A characteristic feature of such dynamics is the absence of thermal (quantum) detailed balance.ContentsPAGE1. Introduction5262. Quantum dynamics in stochastic fields531 2.1. Stochastic Liouville equation531 2.2. Non-Markovian vs. Markovian discrete

  19. Strongly Magnetized Accretion Disks Around Black Holes

    NASA Astrophysics Data System (ADS)

    Salvesen, Greg; Armitage, Philip J.; Simon, Jacob B.; Begelman, Mitchell C.

    2017-01-01

    Recent observations are suggestive of strongly magnetized accretion disks around black holes. Performing local (shearing box) simulations of accretion disks, we investigate how a strong magnetization state can develop and persist. We demonstrate that poloidal flux is a necessary prerequisite for the sustainability of strongly magnetized accretion disks. We also show that black hole spin measurements can become unconstrained if magnetic fields provide a significant contribution to the vertical pressure support of the accretion disk atmosphere.

  20. Biomimicry of surfactant protein C.

    PubMed

    Brown, Nathan J; Johansson, Jan; Barron, Annelise E

    2008-10-01

    Since the widespread use of exogenous lung surfactant to treat neonatal respiratory distress syndrome, premature infant survival and respiratory morbidity have dramatically improved. Despite the effectiveness of the animal-derived surfactant preparations, there still remain some concerns and difficulties associated with their use. This has prompted investigation into the creation of synthetic surfactant preparations. However, to date, no clinically used synthetic formulation is as effective as the natural material. This is largely because the previous synthetic formulations lacked analogues of the hydrophobic proteins of the lung surfactant system, SP-B and SP-C, which are critical functional constituents. As a result, recent investigation has turned toward the development of a new generation of synthetic, biomimetic surfactants that contain synthetic phospholipids along with a mimic of the hydrophobic protein portion of lung surfactant. In this Account, we detail our efforts in creating accurate mimics of SP-C for use in a synthetic surfactant replacement therapy. Despite SP-C's seemingly simple structure, the predominantly helical protein is extraordinarily challenging to work with given its extreme hydrophobicity and structural instability, which greatly complicates the creation of an effective SP-C analogue. Drawing inspiration from Nature, two promising biomimetic approaches have led to the creation of rationally designed biopolymers that recapitulate many of SP-C's molecular features. The first approach utilizes detailed SP-C structure-activity relationships and amino acid folding propensities to create a peptide-based analogue, SP-C33. In SP-C33, the problematic and metastable polyvaline helix is replaced with a structurally stable polyleucine helix and includes a well-placed positive charge to prevent aggregation. SP-C33 is structurally stable and eliminates the association propensity of the native protein. The second approach follows the same design

  1. 77 FR 16131 - Establishing a White House Council on Strong Cities, Strong Communities

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-20

    ... White House Council on Strong Cities, Strong Communities By the authority vested in me as President by...: Section 1. Policy. Cities, towns, and regions across our Nation continue to face difficult economic... established the Strong Cities, Strong Communities (SC2) pilot initiative. By partnering with cities...

  2. Keeping Marriages Strong in Challenging Times

    ERIC Educational Resources Information Center

    Ober, Marci Wolff

    2009-01-01

    What makes a strong marriage anyway...? There are definite qualities that exist in healthy marriages, that is, a marriage that is defined by both partners to be "mostly" or "usually" very satisfying. This article explores these qualities and looks at what really works to make and keep marriages strong, healthy, and satisfying…

  3. On the Strong Direct Summand Conjecture

    ERIC Educational Resources Information Center

    McCullough, Jason

    2009-01-01

    In this thesis, our aim is the study the Vanishing of Maps of Tor Conjecture of Hochster and Huneke. We mainly focus on an equivalent characterization called the Strong Direct Summand Conjecture, due to N. Ranganathan. Our results are separated into three chapters. In Chapter 3, we prove special cases of the Strong Direct Summand Conjecture in…

  4. Strong diamagnetism of normal metals and superconductivity

    NASA Astrophysics Data System (ADS)

    Abramov, O. V.; Gradov, O. M.; Kyrie, A. Yu

    1992-07-01

    The theory of strong diamagnetism of metals caused by the formation of a superlattice with the period being much larger than the crystal cell size has been developed. Strong diamagnetism has been shown to be the cause of the superconductivity of metals.

  5. Seismic switch for strong motion measurement

    DOEpatents

    Harben, Philip E.; Rodgers, Peter W.; Ewert, Daniel W.

    1995-01-01

    A seismic switching device that has an input signal from an existing microseismic station seismometer and a signal from a strong motion measuring instrument. The seismic switch monitors the signal level of the strong motion instrument and passes the seismometer signal to the station data telemetry and recording systems. When the strong motion instrument signal level exceeds a user set threshold level, the seismometer signal is switched out and the strong motion signal is passed to the telemetry system. The amount of time the strong motion signal is passed before switching back to the seismometer signal is user controlled between 1 and 15 seconds. If the threshold level is exceeded during a switch time period, the length of time is extended from that instant by one user set time period.

  6. Seismic switch for strong motion measurement

    DOEpatents

    Harben, P.E.; Rodgers, P.W.; Ewert, D.W.

    1995-05-30

    A seismic switching device is described that has an input signal from an existing microseismic station seismometer and a signal from a strong motion measuring instrument. The seismic switch monitors the signal level of the strong motion instrument and passes the seismometer signal to the station data telemetry and recording systems. When the strong motion instrument signal level exceeds a user set threshold level, the seismometer signal is switched out and the strong motion signal is passed to the telemetry system. The amount of time the strong motion signal is passed before switching back to the seismometer signal is user controlled between 1 and 15 seconds. If the threshold level is exceeded during a switch time period, the length of time is extended from that instant by one user set time period. 11 figs.

  7. Puerto Rico Strong Motion Seismic Network

    NASA Astrophysics Data System (ADS)

    Huerta-Lopez, C. I.; Martínez-Cruzado, J. A.; Martínez-Pagan, J.; Santana-Torres, E. X.; Torres-O, D. M.

    2014-12-01

    The Puerto Rico Strong Motion Seismic Network is currently in charge of the operation of: (i) free-field (ff) strong motion stations, (ii) instrumented structures (STR) (Dams, Bridges, Buildings), and (iii) the data acquisition/monitoring and analysis of earthquakes considered strong from the point of view of their intensity and magnitude. All these instruments are deployed in the Puerto Rico Island (PRI), US-, and British-Virgin Islands (BVI), and Dominican Republic (DR). The Puerto Rico Island and the Caribbean region have high potential to be affected by earthquakes that could be catastrophic for the area. The Puerto Rico Strong Motion Seismic Network (actually Puerto Rico Strong Motion Program, PRSMP) has grown since 1970's from 7 ff strong motion stations and one instrumented building with analog accelerographs to 111 ff strong motion stations and 16 instrumented buildings with digital accelerographs: PRI: 88 ff, 16 STR., DR: 13 ff, BVI: 5 ff, 2 STR collecting data via IP (internet), DU (telephone), and stand alone stations The current stage of the PRSMP seismic network, the analysis of moderate earthquakes that were recorded and/or occurred on the island, results of the intensity distribution of selected earthquakes, as well as results of dynamic parameter identification of some of the instrumented structures are here presented.

  8. Dual field theory of strong interactions

    SciTech Connect

    Akers, D.

    1987-07-01

    A dual field theory of strong interactions is derived from a Lagrangian of the Yang-Mills and Higgs fields. The existence of a magnetic monopole of mass 2397 MeV and Dirac charge g = (137/2)e is incorporated into the theory. Unification of the strong, weak, and electromagnetic forces is shown to converge at the mass of the intermediate vector boson W/sup +/-/. The coupling constants of the strong and weak interactions are derived in terms of the fine-structure constant ..cap alpha.. = 1/137.

  9. Strong photoassociation in a degenerate fermi gas

    NASA Astrophysics Data System (ADS)

    Rvachov, Timur; Jamison, Alan; Jing, Li; Son, Hyungmok; Ebadi, Sepehr; Jiang, Yijun; Zwierlein, Martin; Ketterle, Wolfgang

    2016-05-01

    Despite many studies there remain open questions about strong photoassociation in ultracold gases. We study the effects of strong photoassociation in ultracold fermions. Photoassociation occurs only at short range and thus can be used as a tool to probe and control the two-body correlation function in an interacting many-body system. We study the effects of strong photoassociation in 6 Li, the onset of saturation, and its effects on spin polarized and interacting spin-mixtures. This work was funded by the NSF, ARO-MURI, SAMSUNG, and NSERC.

  10. Strongly magnetized accretion discs require poloidal flux

    NASA Astrophysics Data System (ADS)

    Salvesen, Greg; Armitage, Philip J.; Simon, Jacob B.; Begelman, Mitchell C.

    2016-08-01

    Motivated by indirect observational evidence for strongly magnetized accretion discs around black holes, and the novel theoretical properties of such solutions, we investigate how a strong magnetization state can develop and persist. To this end, we perform local simulations of accretion discs with an initially purely toroidal magnetic field of equipartition strength. We demonstrate that discs with zero net vertical magnetic flux and realistic boundary conditions cannot sustain a strong toroidal field. However, a magnetic pressure-dominated disc can form from an initial configuration with a sufficient amount of net vertical flux and realistic boundary conditions. Our results suggest that poloidal flux is a necessary prerequisite for the sustainability of strongly magnetized accretion discs.

  11. Green jobs and a strong middle class.

    PubMed

    Podesta, John D

    2009-01-01

    Green jobs are critical to building a strong middle class, and millions of green jobs can be created through energy efficiency. The models already exist for this work, but we need sustained investment to bring them to scale.

  12. Electronic spectra of strongly modulated aperiodic structures

    SciTech Connect

    Barache, D. ); Luck, J.M. )

    1994-06-01

    We consider the tight-binding Hamiltonian on strongly modulated aperiodic chains (e.g., quasiperiodic, self-similar, random). The site energies are distributed according to a given binary sequence ([ital V][sub [ital n

  13. Diffusive Mixing in Strongly Coupled Plasmas

    NASA Astrophysics Data System (ADS)

    Diaw, Abdourahmane; Murillo, Michael

    2016-10-01

    A multispecies hydrodynamic model based on moments of the Born-Bogolyubov-Green-Kirkwood-Yvon (BBGKY) hierarchy is developed for physical conditions relevant to astrophysical plasmas. The modified transport equations incorporate strong correlations through a density functional theory closure, while fluctuations enters through a mixture BGK operator. This model extends the usual Burgers equations for a dilute gas to strongly coupled and isothermal plasmas mixtures. The diffusive currents for these strongly coupled plasmas is self-consistently derived. The settling of impurities and its impact on cooling of white dwarfs and neutron stars can be greatly affected by strong Coulomb coupling, which we show can be quantified using the direct-correlation function. This work was supported by the Air Force Office of Scientific Research (Grant No. FA9550-12-1-0344).

  14. Attract Academically Strong Students: Market the Faculty.

    ERIC Educational Resources Information Center

    Rickard, Charles E.; Walters, James C.

    1984-01-01

    Presents a marketing strategy to assist admissions personnel in recruiting academically strong students to colleges and universities. Discusses the importance of institutional prestige and faculty achievement as well as the need to involve faculty in student recruitment. (JAC)

  15. Thermalization of strongly disordered nonlinear chains.

    PubMed

    Kottos, Tsampikos; Shapiro, Boris

    2011-06-01

    Thermalization of systems described by the discrete nonlinear Schrödinger equation, in the strong disorder limit, is investigated both theoretically and numerically. We show that introducing correlations in the disorder potential, while keeping the "effective" disorder fixed (as measured by the localization properties of wave-packet dynamics), strongly facilitates the thermalization process and leads to a standard grand canonical distribution of the probability norms associated with each site.

  16. Evolutionary games on cycles with strong selection.

    PubMed

    Altrock, P M; Traulsen, A; Nowak, M A

    2017-02-01

    Evolutionary games on graphs describe how strategic interactions and population structure determine evolutionary success, quantified by the probability that a single mutant takes over a population. Graph structures, compared to the well-mixed case, can act as amplifiers or suppressors of selection by increasing or decreasing the fixation probability of a beneficial mutant. Properties of the associated mean fixation times can be more intricate, especially when selection is strong. The intuition is that fixation of a beneficial mutant happens fast in a dominance game, that fixation takes very long in a coexistence game, and that strong selection eliminates demographic noise. Here we show that these intuitions can be misleading in structured populations. We analyze mean fixation times on the cycle graph under strong frequency-dependent selection for two different microscopic evolutionary update rules (death-birth and birth-death). We establish exact analytical results for fixation times under strong selection and show that there are coexistence games in which fixation occurs in time polynomial in population size. Depending on the underlying game, we observe inherence of demographic noise even under strong selection if the process is driven by random death before selection for birth of an offspring (death-birth update). In contrast, if selection for an offspring occurs before random removal (birth-death update), then strong selection can remove demographic noise almost entirely.

  17. Evolutionary games on cycles with strong selection

    NASA Astrophysics Data System (ADS)

    Altrock, P. M.; Traulsen, A.; Nowak, M. A.

    2017-02-01

    Evolutionary games on graphs describe how strategic interactions and population structure determine evolutionary success, quantified by the probability that a single mutant takes over a population. Graph structures, compared to the well-mixed case, can act as amplifiers or suppressors of selection by increasing or decreasing the fixation probability of a beneficial mutant. Properties of the associated mean fixation times can be more intricate, especially when selection is strong. The intuition is that fixation of a beneficial mutant happens fast in a dominance game, that fixation takes very long in a coexistence game, and that strong selection eliminates demographic noise. Here we show that these intuitions can be misleading in structured populations. We analyze mean fixation times on the cycle graph under strong frequency-dependent selection for two different microscopic evolutionary update rules (death-birth and birth-death). We establish exact analytical results for fixation times under strong selection and show that there are coexistence games in which fixation occurs in time polynomial in population size. Depending on the underlying game, we observe inherence of demographic noise even under strong selection if the process is driven by random death before selection for birth of an offspring (death-birth update). In contrast, if selection for an offspring occurs before random removal (birth-death update), then strong selection can remove demographic noise almost entirely.

  18. Surface Mediated Protein Disaggregation

    NASA Astrophysics Data System (ADS)

    Radhakrishna, Mithun; Kumar, Sanat K.

    2014-03-01

    Preventing protein aggregation is of both biological and industrial importance. Biologically these aggregates are known to cause amyloid type diseases like Alzheimer's and Parkinson's disease. Protein aggregation leads to reduced activity of the enzymes in industrial applications. Inter-protein interactions between the hydrophobic residues of the protein are known to be the major driving force for protein aggregation. In the current paper we show how surface chemistry and curvature can be tuned to mitigate these inter-protein interactions. Our results calculated in the framework of the Hydrophobic-Polar (HP) lattice model show that, inter-protein interactions can be drastically reduced by increasing the surface hydrophobicity to a critical value corresponding to the adsorption transition of the protein. At this value of surface hydrophobicity, proteins lose inter-protein contacts to gain surface contacts and thus the surface helps in reducing the inter-protein interactions. Further, we show that the adsorption of the proteins inside hydrophobic pores of optimal sizes are most efficient both in reducing inter-protein contacts and simultaneously retaining most of the native-contacts due to strong protein-surface interactions coupled with stabilization due to the confinement. Department of Energy (Grant No DE-FG02-11ER46811).

  19. The Italian Strong Motion Network (RAN)

    NASA Astrophysics Data System (ADS)

    Costa, Giovanni; Ammirati, Alfredo; de Nardis, Rita; Filippi, Luisa; Gallo, Antonella; Lavecchia, Giusy; Sirignano, Sebastiano; Zambonelli, Elisa; Nicoletti, Mario

    2014-05-01

    A network for the strong motion monitoring of the territory allows recording data that provide an excellent opportunity to study the source, path, and site effects on the ground motions, specifically in near source area, for updating seismic hazard map and consequently construction codes and earthquake resistant design. Strong motion data also help to increase the effective preparation and response to seismic emergencies and the ability of a community to quickly recover from the damages of an earthquake contributes to lower the seismic risk usually measured in term of casualties and economic losses. The Italian network for monitoring the strong movement of the national territory (RAN) is the result of a fruitful cooperation over the last 16 years between the Italian government, the regions and local authorities and now counts more than 500 stations. Over the years, as a priority the DPC has focused mainly on the expansion of the network in terms of the number of measurement points and technological improvement of instrumentation as well as the data transmission system. A data acquisition centre was implemented in which the Antelope software collects, processes and archives, automatically, the data of the RAN and of the external strong motion networks that contribute to the database of the RAN. Recently the DPC has dedicated specific resources to improve the response of the network, in particular, in case of emergency. The efficiency of the network on a daily basis is not less than 95% and temporary networks were installed in the epicentral area within 24 hours after the earthquake and connected to the data acquisition centre in Rome. A fast seismic data analysis is essential to provide useful information to Authorities which make decisions immediately after a strong earthquake occurrence. During a strong earthquake, the modern accelerometers are the only instruments which can provide near source high-quality data that are important both for scientific and for civil

  20. Strong Motion Recording in the United States

    NASA Astrophysics Data System (ADS)

    Archuleta, R. J.; Fletcher, J. B.; Shakal, A. F.

    2014-12-01

    The United States strong motion program began in 1932 when the Coast and Geodetic Survey (C&GS) installed eight strong motion accelerographs in California. During the March 1933 Long Beach earthquake, three of these produced the first strong motion records. With this success the C&GS expanded the number of accelerographs to 71 by 1964. With development of less expensive, mass-produced accelerographs the number of strong motion accelerographs expanded to ~575 by 1972. Responsibilities for operating the network and disseminating data were transferred to the National Oceanic and Atmospheric Administration in 1970 and then to the U.S. Geological Survey in 1973. In 1972 the California Legislature established the California Strong Motion Instrumentation Program (CSMIP). CSMIP operates accelerographs at 812 ground stations, with multi-channel accelerographs in 228 buildings, 125 lifelines and 37 geotechnical arrays, in California. The USGS and the ANSS effort operate accelerographs at 1584 ground stations, 96 buildings, 14 bridges, 70 dams, and 15 multi-channel geotechnical arrays. The USC Los Angeles array has 78 ground stations; UCSB operates 5 geotechnical arrays; other government and private institutions also operate accelerographs. Almost all accelerographs are now digital with a sampling rate of 200 Hz. Most of the strong motion data can be downloaded from the Center for Engineering Strong Motion Data (http://strongmotioncenter.org). As accelerographs have become more sophisticated, the concept of what constitutes strong motion has blurred because small earthquakes (M ~3) are well recorded on accelerometers as well as seismometers. However, when accelerations are over ~10%g and velocities over ~1 cm/s, the accelerometers remain on scale, providing the unclipped data necessary to analyze the ground motion and its consequences. Strong motion data are essential to the development of ground motion prediction equations, understanding structural response, performance

  1. Visible periodicity of strong nucleosome DNA sequences.

    PubMed

    Salih, Bilal; Tripathi, Vijay; Trifonov, Edward N

    2015-01-01

    Fifteen years ago, Lowary and Widom assembled nucleosomes on synthetic random sequence DNA molecules, selected the strongest nucleosomes and discovered that the TA dinucleotides in these strong nucleosome sequences often appear at 10-11 bases from one another or at distances which are multiples of this period. We repeated this experiment computationally, on large ensembles of natural genomic sequences, by selecting the strongest nucleosomes--i.e. those with such distances between like-named dinucleotides, multiples of 10.4 bases, the structural and sequence period of nucleosome DNA. The analysis confirmed the periodicity of TA dinucleotides in the strong nucleosomes, and revealed as well other periodic sequence elements, notably classical AA and TT dinucleotides. The matrices of DNA bendability and their simple linear forms--nucleosome positioning motifs--are calculated from the strong nucleosome DNA sequences. The motifs are in full accord with nucleosome positioning sequences derived earlier, thus confirming that the new technique, indeed, detects strong nucleosomes. Species- and isochore-specific variations of the matrices and of the positioning motifs are demonstrated. The strong nucleosome DNA sequences manifest the highest hitherto nucleosome positioning sequence signals, showing the dinucleotide periodicities in directly observable rather than in hidden form.

  2. Global gyrokinetic simulations with strong flows

    NASA Astrophysics Data System (ADS)

    Collier, J. D.; McMillan, B. F.; Robinson, J. R.

    2016-11-01

    We report on the investigation of strong toroidal rotation effects in a global tokamak code, ORB5. This includes the implementation of a strong flow gyrokinetic Lagrangian, allowing a complete treatment of centrifugal and Coriolis effects in the laboratory frame. In order to consistently perform the linear analysis in this system, an axisymmetric gyrokinetic equilibrium distribution function is defined using the constants of motion: we show it corresponds to the standard choice in the local limit and is close to the neoclassical solution in the banana regime. The energy and momentum transport equations are presented in an analogous form to those for the weak flow system. Linear studies of Ion Temperature Gradient (ITG) modes in rotating plasmas are performed to determine how the global effects interact with the effects of strong rotation. We also determine the geodesic acoustic mode dispersion with respect to plasma rotation rate in this gyrokinetic model and compare it to MHD theory.

  3. Multiscale equations for strongly stratified turbulent flows

    NASA Astrophysics Data System (ADS)

    Chini, Greg; Rocha, Cesar; Julien, Keith; Caulfield, Colm-Cille

    2016-11-01

    Strongly stratified turbulent shear flows are of fundamental importance owing to their widespread occurrence and their impact on diabatic mixing, yet direct numerical simulations of such flows remain challenging. Here, a reduced, multiscale description of turbulent shear flows in the presence of strong stable density stratification is derived via asymptotic analysis of the governing Boussinesq equations. The analysis explicitly recognizes the occurrence of dynamics on disparate spatiotemoporal scales, and yields simplified partial differential equations governing the coupled evolution of slowly-evolving small aspect-ratio ('pancake') modes and isotropic, strongly non-hydrostatic stratified-shear (e.g. Kelvin-Helmholtz) instability modes. The reduced model is formally valid in the physically-relevant regime in which the aspect-ratio of the pancake structures tends to zero in direct proportion to the horizontal Froude number. Relative to the full Boussinesq equations, the model offers both computational and conceptual advantages.

  4. Strong field laser control of photochemistry.

    PubMed

    Solá, Ignacio R; González-Vázquez, Jesús; de Nalda, Rebeca; Bañares, Luis

    2015-05-28

    Strong ultrashort laser pulses have opened new avenues for the manipulation of photochemical processes like photoisomerization or photodissociation. The presence of light intense enough to reshape the potential energy surfaces may steer the dynamics of both electrons and nuclei in new directions. A controlled laser pulse, precisely defined in terms of spectrum, time and intensity, is the essential tool in this type of approach to control chemical dynamics at a microscopic level. In this Perspective we examine the current strategies developed to achieve control of chemical processes with strong laser fields, as well as recent experimental advances that demonstrate that properties like the molecular absorption spectrum, the state lifetimes, the quantum yields and the velocity distributions in photodissociation processes can be controlled by the introduction of carefully designed strong laser fields.

  5. Strongly nonlinear stress waves in dissipative metamaterials

    NASA Astrophysics Data System (ADS)

    Xu, Yichao; Nesterenko, Vitali F.

    2017-01-01

    We present the results of measurements and numerical simulations of stress wave propagation in a one-dimensional strongly nonlinear dissipative metamaterial composed of steel disks and Nitrile O-rings. The incoming bell shape stress wave is generated by the strikers with different masses. Numerical modeling including a viscous dissipative term to describe dynamic behavior of O-rings is developed to predict the wave amplitude, shape and propagation speed of stress waves. The viscous dissipation prevented the incoming pulse from splitting into trains of solitary waves typical for non-dissipative strongly nonlinear discrete systems. The linear momentum and energy from the striker were completely transferred into this strongly nonlinear "soft" metamaterial.

  6. Nanostructure studies of strongly correlated materials.

    PubMed

    Wei, Jiang; Natelson, Douglas

    2011-09-01

    Strongly correlated materials exhibit an amazing variety of phenomena, including metal-insulator transitions, colossal magnetoresistance, and high temperature superconductivity, as strong electron-electron and electron-phonon couplings lead to competing correlated ground states. Recently, researchers have begun to apply nanostructure-based techniques to this class of materials, examining electronic transport properties on previously inaccessible length scales, and applying perturbations to drive systems out of equilibrium. We review progress in this area, particularly emphasizing work in transition metal oxides (Fe(3)O(4), VO(2)), manganites, and high temperature cuprate superconductors. We conclude that such nanostructure-based studies have strong potential to reveal new information about the rich physics at work in these materials.

  7. Coherency properties of strong Langmuir turbulence

    SciTech Connect

    Rose, H.A.; DuBois, D.F.; Russell, D. )

    1989-01-01

    Strongly correlated Langmuir wave collapse has been observed in two dimensional simulations of Zakharov's model in a regime characterized by strong ion sound wave damping and an external drive frequency, {omega}{sub 0}, close to but less than the plasma frequency, ({omega}{sub p} {minus} {omega}{sub 0})/{omega}{sub 0} > {epsilon} with {epsilon} {approx equal} 0.005. Caviton-caviton interactions induce temporal correlations between different collapse sites on a time scale the order of a collapse cycle, and on a longer time scale site locations migrate possibly leading to strong spatial correlations. Certain features of ionospheric incoherent scatter radar (ISR) spectra are consistent with such correlations. 6 refs.

  8. Metallic Clusters in Strong Femtosecond Laser Pulses

    NASA Astrophysics Data System (ADS)

    Suraud, Eric; Reinhard, P.-G.; Ullrich, Carsten A.

    1998-03-01

    We present a theoretical study of the electron response of a Na_9^+ cluster excited by strong femtosecond laser pulses.(C. A. Ullrich, P.-G. Reinhard, and E. Suraud, J. Phys. B 30), 5043 (1997) Our approach is based on time-dependent density functional theory within the adiabatic local density approximation, including a recently developed self-interaction correction scheme. We investigate numerically the full electronic dipolar response and multiphoton ionization of the cluster and discuss the ionization mechanism. A strong correlation between induced electronic dipole oscillations and electron emission is observed, leading to a pronounced resonant enhancement of ionization at the frequency of the Mie plasmon.

  9. Strong Purifying Selection in Transmission of Mammalian Mitochondrial DNA

    PubMed Central

    Stewart, James Bruce; Freyer, Christoph; Elson, Joanna L; Wredenberg, Anna; Cansu, Zekiye; Trifunovic, Aleksandra; Larsson, Nils-Göran

    2008-01-01

    There is an intense debate concerning whether selection or demographics has been most important in shaping the sequence variation observed in modern human mitochondrial DNA (mtDNA). Purifying selection is thought to be important in shaping mtDNA sequence evolution, but the strength of this selection has been debated, mainly due to the threshold effect of pathogenic mtDNA mutations and an observed excess of new mtDNA mutations in human population data. We experimentally addressed this issue by studying the maternal transmission of random mtDNA mutations in mtDNA mutator mice expressing a proofreading-deficient mitochondrial DNA polymerase. We report a rapid and strong elimination of nonsynonymous changes in protein-coding genes; the hallmark of purifying selection. There are striking similarities between the mutational patterns in our experimental mouse system and human mtDNA polymorphisms. These data show strong purifying selection against mutations within mtDNA protein-coding genes. To our knowledge, our study presents the first direct experimental observations of the fate of random mtDNA mutations in the mammalian germ line and demonstrates the importance of purifying selection in shaping mitochondrial sequence diversity. PMID:18232733

  10. Markovian evolution of strongly coupled harmonic oscillators

    NASA Astrophysics Data System (ADS)

    Joshi, Chaitanya; Öhberg, Patrik; Cresser, James D.; Andersson, Erika

    2014-12-01

    We investigate how to model Markovian evolution of coupled harmonic oscillators, each of them interacting with a local environment. When the coupling between the oscillators is weak, dissipation may be modeled using local Lindblad terms for each of the oscillators in the master equation, as is commonly done. When the coupling between oscillators is strong, this model may become invalid. We derive a master equation for two coupled harmonic oscillators that are subject to individual heat baths modeled by a collection of harmonic oscillators and show that this master equation in general contains nonlocal Lindblad terms. We compare the resulting time evolution with that obtained for dissipation through local Lindblad terms for each individual oscillator and show that the evolution is different in the two cases. In particular, the two descriptions give different predictions for the steady state and for the entanglement between strongly coupled oscillators. This shows that when describing strongly coupled harmonic oscillators, one must take great care in how dissipation is modeled and that a description using local Lindblad terms may fail. This may be particularly relevant when attempting to generate entangled states of strongly coupled quantum systems.

  11. MRS photodiode in strong magnetic field

    SciTech Connect

    Beznosko, D.; Blazey, G.; Dyshkant, A.; Francis, K.; Kubik, D.; Rykalin, V.; Tartaglia, M.A.; Zutshi, v.; /Northern Illinois U.

    2004-12-01

    The experimental results on the performance of the MRS (Metal/Resistor/Semiconductor) photodiode in the strong magnetic field of 4.4T, and the possible impact of the quench of the magnet at 4.5T on sensor's operation are reported.

  12. Semimetallization of dielectrics in strong optical fields

    DOE PAGES

    Kwon, Ojoon; Paasch-Colberg, Tim; Apalkov, Vadym; ...

    2016-02-18

    At the heart of ever growing demands for faster signal processing is ultrafast charge transport and control by electromagnetic fields in semiconductors. Intense optical fields have opened fascinating avenues for new phenomena and applications in solids. Because the period of optical fields is on the order of a femtosecond, the current switching and its control by an optical field may pave a way to petahertz optoelectronic devices. Lately, a reversible semimetallization in fused silica on a femtosecond time scale by using a few-cycle strong field (~1 V/Å) is manifested. The strong Wannier-Stark localization and Zener-type tunneling were expected to drivemore » this ultrafast semimetallization. Wider spread of this technology demands better understanding of whether the strong field behavior is universally similar for different dielectrics. Here we employ a carrier-envelope-phase stabilized, few-cycle strong optical field to drive the semimetallization in sapphire, calcium fluoride and quartz and to compare this phenomenon and show its remarkable similarity between them. The similarity in response of these materials, despite the distinguishable differences in their physical properties, suggests the universality of the physical picture explained by the localization of Wannier-Stark states. Lastly, our results may blaze a trail to PHz-rate optoelectronics.« less

  13. Strong Female Characters in Recent Children's Literature.

    ERIC Educational Resources Information Center

    Heine, Pat; Inkster, Christine; Kazemek, Frank; Williams, Sandra; Raschke, Sylvia; Stevens, Della

    1999-01-01

    Shares the authors' criteria for evaluating female characters as positive role models in children's literature. Explores the criteria by examining "The Ballad of Lucy Wipple" (Karen Cushman). Discusses other recently published picture books and novels which feature strong females in history, in contemporary times, and in fantasy. (SR)

  14. Patterns of strong coupling for LHC searches

    NASA Astrophysics Data System (ADS)

    Liu, Da; Pomarol, Alex; Rattazzi, Riccardo; Riva, Francesco

    2016-11-01

    Even though the Standard Model (SM) is weakly coupled at the Fermi scale, a new strong dynamics involving its degrees of freedom may conceivably lurk at slightly higher energies, in the multi TeV range. Approximate symmetries provide a structurally robust context where, within the low energy description, the dimensionless SM couplings are weak, while the new strong dynamics manifests itself exclusively through higher-derivative interactions. We present an exhaustive classification of such scenarios in the form of effective field theories, paying special attention to new classes of models where the strong dynamics involves, along with the Higgs boson, the SM gauge bosons and/or the fermions. The IR softness of the new dynamics suppresses its effects at LEP energies, but deviations are in principle detectable at the LHC, even at energies below the threshold for production of new states. We believe our construction provides the so far unique structurally robust context where to motivate several LHC searches in Higgs physics, diboson production, or W W scattering. Perhaps surprisingly, the interplay between weak coupling, strong coupling and derivatives, which is controlled by symmetries, can override the naive expansion in operator dimension, providing instances where dimension-8 dominates dimension-6, well within the domain of validity of the low energy effective theory. This result reveals the limitations of an analysis that is both ambitiously general and restricted to dimension-6 operators.

  15. Strong motion duration and earthquake magnitude relationships

    SciTech Connect

    Salmon, M.W.; Short, S.A.; Kennedy, R.P.

    1992-06-01

    Earthquake duration is the total time of ground shaking from the arrival of seismic waves until the return to ambient conditions. Much of this time is at relatively low shaking levels which have little effect on seismic structural response and on earthquake damage potential. As a result, a parameter termed ``strong motion duration`` has been defined by a number of investigators to be used for the purpose of evaluating seismic response and assessing the potential for structural damage due to earthquakes. This report presents methods for determining strong motion duration and a time history envelope function appropriate for various evaluation purposes, for earthquake magnitude and distance, and for site soil properties. There are numerous definitions of strong motion duration. For most of these definitions, empirical studies have been completed which relate duration to earthquake magnitude and distance and to site soil properties. Each of these definitions recognizes that only the portion of an earthquake record which has sufficiently high acceleration amplitude, energy content, or some other parameters significantly affects seismic response. Studies have been performed which indicate that the portion of an earthquake record in which the power (average rate of energy input) is maximum correlates most closely with potential damage to stiff nuclear power plant structures. Hence, this report will concentrate on energy based strong motion duration definitions.

  16. Semimetallization of dielectrics in strong optical fields

    SciTech Connect

    Kwon, Ojoon; Apalkov, Vadym; Kim, Bum -Kyu; Kim, Ju -Jin; Stockman, Mark I.; Kim, D.

    2016-02-18

    At the heart of ever growing demands for faster signal processing is ultrafast charge transport and control by electromagnetic fields in semiconductors. Intense optical fields have opened fascinating avenues for new phenomena and applications in solids. Because the period of optical fields is on the order of a femtosecond, the current switching and its control by an optical field may pave a way to petahertz optoelectronic devices. Lately, a reversible semimetallization in fused silica on a femtosecond time scale by using a few-cycle strong field (~1 V/Å) is manifested. The strong Wannier-Stark localization and Zener-type tunneling were expected to drive this ultrafast semimetallization. Wider spread of this technology demands better understanding of whether the strong field behavior is universally similar for different dielectrics. Here we employ a carrier-envelope-phase stabilized, few-cycle strong optical field to drive the semimetallization in sapphire, calcium fluoride and quartz and to compare this phenomenon and show its remarkable similarity between them. The similarity in response of these materials, despite the distinguishable differences in their physical properties, suggests the universality of the physical picture explained by the localization of Wannier-Stark states. Lastly, our results may blaze a trail to PHz-rate optoelectronics.

  17. Strongly correlated photons on a chip

    NASA Astrophysics Data System (ADS)

    Reinhard, Andreas; Volz, Thomas; Winger, Martin; Badolato, Antonio; Hennessy, Kevin J.; Hu, Evelyn L.; Imamoğlu, Ataç

    2012-02-01

    Optical nonlinearities at the single-photon level are key ingredients for future photonic quantum technologies. Prime candidates for the realization of the strong photon-photon interactions necessary for implementing quantum information processing tasks, as well as for studying strongly correlated photons in an integrated photonic device setting, are quantum dots embedded in photonic-crystal nanocavities. Here, we report strong quantum correlations between photons on picosecond timescales. We observe (i) photon antibunching upon resonant excitation of the lowest-energy polariton state, proving that the first cavity photon blocks the subsequent injection events, and (ii) photon bunching when the laser field is in two-photon resonance with the polariton eigenstates of the second Jaynes-Cummings manifold, demonstrating that two photons at this colour are more likely to be injected into the cavity jointly than they would otherwise. Together, these results demonstrate unprecedented strong single-photon nonlinearities, paving the way for the realization of a quantum optical Josephson interferometer or a single-photon transistor.

  18. Semimetallization of dielectrics in strong optical fields

    NASA Astrophysics Data System (ADS)

    Kwon, Ojoon; Paasch-Colberg, Tim; Apalkov, Vadym; Kim, Bum-Kyu; Kim, Ju-Jin; Stockman, Mark I.; Kim, D.

    2016-02-01

    At the heart of ever growing demands for faster signal processing is ultrafast charge transport and control by electromagnetic fields in semiconductors. Intense optical fields have opened fascinating avenues for new phenomena and applications in solids. Because the period of optical fields is on the order of a femtosecond, the current switching and its control by an optical field may pave a way to petahertz optoelectronic devices. Lately, a reversible semimetallization in fused silica on a femtosecond time scale by using a few-cycle strong field (~1 V/Å) is manifested. The strong Wannier-Stark localization and Zener-type tunneling were expected to drive this ultrafast semimetallization. Wider spread of this technology demands better understanding of whether the strong field behavior is universally similar for different dielectrics. Here we employ a carrier-envelope-phase stabilized, few-cycle strong optical field to drive the semimetallization in sapphire, calcium fluoride and quartz and to compare this phenomenon and show its remarkable similarity between them. The similarity in response of these materials, despite the distinguishable differences in their physical properties, suggests the universality of the physical picture explained by the localization of Wannier-Stark states. Our results may blaze a trail to PHz-rate optoelectronics.

  19. Semimetallization of dielectrics in strong optical fields

    PubMed Central

    Kwon, Ojoon; Paasch-Colberg, Tim; Apalkov, Vadym; Kim, Bum-Kyu; Kim, Ju-Jin; Stockman, Mark I.; Kim, D.

    2016-01-01

    At the heart of ever growing demands for faster signal processing is ultrafast charge transport and control by electromagnetic fields in semiconductors. Intense optical fields have opened fascinating avenues for new phenomena and applications in solids. Because the period of optical fields is on the order of a femtosecond, the current switching and its control by an optical field may pave a way to petahertz optoelectronic devices. Lately, a reversible semimetallization in fused silica on a femtosecond time scale by using a few-cycle strong field (~1 V/Å) is manifested. The strong Wannier-Stark localization and Zener-type tunneling were expected to drive this ultrafast semimetallization. Wider spread of this technology demands better understanding of whether the strong field behavior is universally similar for different dielectrics. Here we employ a carrier-envelope-phase stabilized, few-cycle strong optical field to drive the semimetallization in sapphire, calcium fluoride and quartz and to compare this phenomenon and show its remarkable similarity between them. The similarity in response of these materials, despite the distinguishable differences in their physical properties, suggests the universality of the physical picture explained by the localization of Wannier-Stark states. Our results may blaze a trail to PHz-rate optoelectronics. PMID:26888147

  20. Strong correlations in bosons and fermions

    NASA Astrophysics Data System (ADS)

    Tilahun, Dagim

    If there is a general theme to this thesis, it is the effects of strong correlations in both bosons and fermions. The bosonic system considered here consists of ultracold alkali atoms trapped by interfering lasers, so called optical lattices. Strong interactions, realized by increasing the depth of the lattice potential, or through the phenomenon of Feshbach resonances induce strong correlations amongst the atoms, rendering attempts to describe the systems in terms of single particle type physics unsuccessful. Of course strong correlations are not the exclusive domain of bosons, and also are not caused only by strong interactions. Other factors such as reduced dimensionality, in one-dimensional electron gases, or strong magnetic fields, in two-dimensional electron gases are known to induce strong correlations. In this thesis, we explore the manifestations of strong correlations in ultracold atoms in optical lattices and interacting electron gases. Optical lattices provide a near-perfect realization of lattice models, such as the bosonic Hubbard model (BHM) that have been formulated to study solid state systems. This follows from the absence of defects or impurities that usually plague real solid state systems. Another novel feature of optical lattices is the unprecedented control experimenters have in tuning the different lattice parameters, such as the lattice spacing and the intensity of the lasers. This control enables one to study the model Hamiltonians over a wide range of variables, such as the interaction strength between the atoms, thereby opening the door towards the observation of diverse and interesting phenomena. The BHM, and also its variants, predict various quantum phases, such as the strongly correlated Mott insulator (MI) phase that appears as a function of the parameter t/U, the ratio of the nearest neighbor hopping amplitude to the on-site interaction, which one varies experimentally over a wide range of values simply by switching the intensity

  1. Using Strong Magnetic Fields to Control Solutal Convection

    NASA Technical Reports Server (NTRS)

    Ramachandran, N.; Leslie, F. W.

    2003-01-01

    An important component in biotechnology, particularly in the area of protein engineering and rational drug design is the knowledge of the precise three-dimensional molecular structure of proteins. The quality of structural information obtained from X-ray diffraction methods is directly dependent on the degree of perfection of the protein crystals. As a consequence, the growth of high quality macromolecular crystals for diffraction analyses has been the central focus for biochemists, biologists, and bioengineers. Macromolecular crystals are obtained from solutions that contain the crystallizing species in equilibrium with higher aggregates, ions, precipitants, other possible phases of the protein, foreign particles, the walls of the container, and a likely host of other impurities. By changing transport modes in general, i.e., reduction of convection and sedimentation, as is achieved in microgravity , we have been able to dramatically affect the movement and distribution of macromolecules in the fluid, and thus their transport, formation of crystal nuclei, and adsorption to the crystal surface. While a limited number of high quality crystals from space flights have been obtained, as the recent National Research Council (NRC) review of the NASA microgravity crystallization program pointed out, the scientific approach and research in crystallization of proteins has been mainly empirical yielding inconclusive results. We postulate that we can reduce convection in ground-based experiments and we can understand the different aspects of convection control through the use of strong magnetic fields and field gradients. We postulate that limited convection in a magnetic field will provide the environment for the growth of high quality crystals. The approach exploits the variation of fluid magnetic susceptibility with concentration for this purpose and the convective damping is realized by appropriately positioning the crystal growth cell so that the magnetic susceptibility

  2. Solvable model of a strongly driven micromaser

    SciTech Connect

    Lougovski, P.; Walther, H.; Casagrande, F.; Lulli, A.; Englert, B.-G.; Solano, E.

    2004-02-01

    We study the dynamics of a micromaser where the pumping atoms are strongly driven by a resonant classical field during their transit through the cavity mode. We derive a master equation for this strongly driven micromaser, involving the contributions of the unitary atom-field interactions and the dissipative effects of a thermal bath. We find analytical solutions for the temporal evolution and the steady state of this system by means of phase-space techniques, providing an unusual solvable model of an open quantum system, including pumping and decoherence. We derive closed expressions for all relevant expectation values, describing the statistics of the cavity field and the detected atomic levels. The transient regime shows the buildup of mixtures of mesoscopic fields evolving towards a super-Poissonian steady-state field that, nevertheless, yields atomic correlations that exhibit stronger nonclassical features than the conventional micromaser.

  3. Strong correlation induced charge localization in antiferromagnets

    PubMed Central

    Zhu, Zheng; Jiang, Hong-Chen; Qi, Yang; Tian, Chushun; Weng, Zheng-Yu

    2013-01-01

    The fate of a hole injected in an antiferromagnet is an outstanding issue of strongly correlated physics. It provides important insights into doped Mott insulators closely related to high-temperature superconductivity. Here, we report a systematic numerical study of t-J ladder systems based on the density matrix renormalization group. It reveals a surprising result for the single hole's motion in an otherwise well-understood undoped system. Specifically, we find that the common belief of quasiparticle picture is invalidated by the self-localization of the doped hole. In contrast to Anderson localization caused by disorders, the charge localization discovered here is an entirely new phenomenon purely of strong correlation origin. It results from destructive quantum interference of novel signs picked up by the hole, and since the same effect is of a generic feature of doped Mott physics, our findings unveil a new paradigm which may go beyond the single hole doped system. PMID:24002668

  4. New strong interactions above the electroweak scale

    SciTech Connect

    White, A.R.

    1994-08-09

    Theoretical arguments for a new higher-color quark sector, based on Pomeron physics in QCD, are briefly described. The electroweak symmetry-breaking, Strong CP conservation, and electroweak scale CP violation, that is naturally produced by this sector is also outlined. A further consequence is that above the electroweak scale there will be a radical change in the strong interaction. Electroweak states, in particular multiple W`s and Z`s, and new, semi-stable, very massive, baryons, will be commonly produced. The possible correlation of expected phenomena with a wide range of observed Cosmic Ray effects at and above the primary spectrum knee is described. Related phenomena that might be seen in the highest energy hard scattering events at the Fermilab Tevatron, some of which could be confused with top production, are also briefly discussed.

  5. Cosmogenic photons strongly constrain UHECR source models

    NASA Astrophysics Data System (ADS)

    van Vliet, Arjen

    2017-03-01

    With the newest version of our Monte Carlo code for ultra-high-energy cosmic ray (UHECR) propagation, CRPropa 3, the flux of neutrinos and photons due to interactions of UHECRs with extragalactic background light can be predicted. Together with the recently updated data for the isotropic diffuse gamma-ray background (IGRB) by Fermi LAT, it is now possible to severely constrain UHECR source models. The evolution of the UHECR sources especially plays an important role in the determination of the expected secondary photon spectrum. Pure proton UHECR models are already strongly constrained, primarily by the highest energy bins of Fermi LAT's IGRB, as long as their number density is not strongly peaked at recent times.

  6. Firefly flashing under strong static magnetic field.

    PubMed

    Barua, Anurup Gohain; Iwasaka, Masakazu; Miyashita, Yuito; Kurita, Satoru; Owada, Norio

    2012-02-01

    Firefly flashing has been the subject of numerous scientific investigations. Here we present in vivo flashes from male specimens of three species of fireflies-two Japanese species Luciola cruciata, Luciola lateralis and one Indian species Luciola praeusta-positioned under a superconducting magnet. When the OFF state of the firefly becomes long after flashing in an immobile state under the strong static magnetic field of strength 10 Tesla for a long time, which varies widely from species to species as well as from specimen to specimen, the effect of the field becomes noticeable. The flashes in general are more rapid, and occasionally overlap to produce broad compound flashes. We present the broadest flashes recorded to date, and propose that the strong static magnetic field affects the neural activities of fireflies, especially those in the spent up or 'exhausted' condition.

  7. Strong sum distance in fuzzy graphs.

    PubMed

    Tom, Mini; Sunitha, Muraleedharan Shetty

    2015-01-01

    In this paper the idea of strong sum distance which is a metric, in a fuzzy graph is introduced. Based on this metric the concepts of eccentricity, radius, diameter, center and self centered fuzzy graphs are studied. Some properties of eccentric nodes, peripheral nodes and central nodes are obtained. A characterisation of self centered complete fuzzy graph is obtained and conditions under which a fuzzy cycle is self centered are established. We have proved that based on this metric, an eccentric node of a fuzzy tree G is a fuzzy end node of G and a node is an eccentric node of a fuzzy tree if and only if it is a peripheral node of G and the center of a fuzzy tree consists of either one or two neighboring nodes. The concepts of boundary nodes and interior nodes in a fuzzy graph based on strong sum distance are introduced. Some properties of boundary nodes, interior nodes and complete nodes are studied.

  8. Molecular systems in a strong magnetic field

    NASA Astrophysics Data System (ADS)

    Turbiner, Alexander V.

    2007-04-01

    Brief overview of one-two electron molecular systems made out of protons and/or α-particles in a strong magnetic field B≤4.414×1013 G is presented. A particular emphasis is given to the one-electron exotic ions H 3 ++ (pppe), He 2 3+ (α α e) and to two-electron ionsH 3 + (pppee), He 2 ++ (α α ee). Quantitative studies in a strong magnetic field are very complicated technically. Novel approach to the few-electron Coulomb systems in magnetic field, which provides accurate results, based on variational calculus with physically relevant trial functions is briefly described.

  9. Strong gravitational lensing and dark energy complementarity

    SciTech Connect

    Linder, Eric V.

    2004-01-21

    In the search for the nature of dark energy most cosmological probes measure simple functions of the expansion rate. While powerful, these all involve roughly the same dependence on the dark energy equation of state parameters, with anticorrelation between its present value w{sub 0} and time variation w{sub a}. Quantities that have instead positive correlation and so a sensitivity direction largely orthogonal to, e.g., distance probes offer the hope of achieving tight constraints through complementarity. Such quantities are found in strong gravitational lensing observations of image separations and time delays. While degeneracy between cosmological parameters prevents full complementarity, strong lensing measurements to 1 percent accuracy can improve equation of state characterization by 15-50 percent. Next generation surveys should provide data on roughly 105 lens systems, though systematic errors will remain challenging.

  10. Decay of Resonaces in Strong Magnetic Field

    NASA Astrophysics Data System (ADS)

    Filip, Peter

    2015-08-01

    We suggest that decay properties (branching ratios) of hadronic resonances may become modified in strong external magnetic field. The behavior of K±*, K0* vector mesons as well as Λ* (1520) and Ξ0* baryonic states is considered in static fields 1013-1015 T. In particular, n = 0 Landau level energy increase of charged particles in the external magnetic field, and the interaction of hadron magnetic moments with the field is taken into account. We suggest that enhanced yield of dileptons and photons from ρ0(770) mesons may occur if strong decay channel ρ0 → π+π- is significantly suppressed. CP - violating π+π- decays of pseudoscalar ηc and η(547) mesons in the magnetic field are discussed, and superpositions of quarkonium states ηc,b and χc,b(nP) with Ψ(nS), ϒ(nS) mesons in the external field are considered.

  11. Strong ground motion prediction using virtual earthquakes.

    PubMed

    Denolle, M A; Dunham, E M; Prieto, G A; Beroza, G C

    2014-01-24

    Sedimentary basins increase the damaging effects of earthquakes by trapping and amplifying seismic waves. Simulations of seismic wave propagation in sedimentary basins capture this effect; however, there exists no method to validate these results for earthquakes that have not yet occurred. We present a new approach for ground motion prediction that uses the ambient seismic field. We apply our method to a suite of magnitude 7 scenario earthquakes on the southern San Andreas fault and compare our ground motion predictions with simulations. Both methods find strong amplification and coupling of source and structure effects, but they predict substantially different shaking patterns across the Los Angeles Basin. The virtual earthquake approach provides a new approach for predicting long-period strong ground motion.

  12. Photoneutrino energy losses in strong magnetic fields.

    NASA Technical Reports Server (NTRS)

    Canuto, V.; Fassio-Canuto, L.

    1973-01-01

    Previously computed rates of energy losses (Petrosian et al., 1967) ignored the presence of strong magnetic fields, hence the change brought in when such a field (about 10 to the 12th to 10 to the 13th power G) is included is studied. The results indicate that for T about 10 to the 8th power K and densities rho of about 10,000 g/cu cm, the presence of a strong H field decreases the energy losses by at the most a factor between 10 and 100 in the region up to rho = 1,000,000 g/cu cm. At higher densities the neutrino emissivities are almost identical.

  13. Peltier effect in strongly driven quantum wires

    NASA Astrophysics Data System (ADS)

    Mierzejewski, M.; Crivelli, D.; Prelovšek, P.

    2014-08-01

    We study a microscopic model of a thermocouple device with two connected correlated quantum wires driven by a constant electric field. In such a closed system we follow the time and position dependence of the entropy density using the concept of the reduced density matrix. At weak driving, the initial changes of the entropy at the junctions can be described by the linear Peltier response. At longer times the quasiequilibrium situation is reached with well defined local temperatures which increase due to an overall Joule heating. On the other hand, a strong electric field induces a nontrivial nonlinear thermoelectric response, e.g., the Bloch oscillations of the energy current. Moreover, we show for the doped Mott insulators that strong driving can reverse the Peltier effect.

  14. Quantum strongly secure ramp secret sharing

    NASA Astrophysics Data System (ADS)

    Zhang, Paul; Matsumoto, Ryutaroh

    2015-02-01

    Quantum secret sharing is a scheme for encoding a quantum state (the secret) into multiple shares and distributing them among several participants. If a sufficient number of shares are put together, then the secret can be fully reconstructed. If an insufficient number of shares are put together however, no information about the secret can be revealed. In quantum ramp secret sharing, partial information about the secret is allowed to leak to a set of participants, called an unqualified set, that cannot fully reconstruct the secret. By allowing this, the size of a share can be drastically reduced. This paper introduces a quantum analog of classical strong security in ramp secret sharing schemes. While the ramp secret sharing scheme still leaks partial information about the secret to unqualified sets of participants, the strong security condition ensures that qudits with critical information can no longer be leaked.

  15. NON-PARAMETRIC ESTIMATION UNDER STRONG DEPENDENCE

    PubMed Central

    Zhao, Zhibiao; Zhang, Yiyun; Li, Runze

    2014-01-01

    We study non-parametric regression function estimation for models with strong dependence. Compared with short-range dependent models, long-range dependent models often result in slower convergence rates. We propose a simple differencing-sequence based non-parametric estimator that achieves the same convergence rate as if the data were independent. Simulation studies show that the proposed method has good finite sample performance. PMID:25018572

  16. Strong transverse fields in delta-spots

    NASA Technical Reports Server (NTRS)

    Zirin, Harold; Wang, Haimin

    1993-01-01

    Spectroscopic measurements of the strength and direction of transverse magnetic fields in six delta-spots are presented. The field direction is determined by the relative strength of the pi- and sigma-components at different polarizer orientations, and is, with one exception, parallel to the neutral line and as strong as the umbral field. Field strengths determined by line splitting are as high as 3980 G.

  17. Kinetic Characterization of Strongly Coupled Systems

    SciTech Connect

    Knapek, C. A.; Ivlev, A. V.; Klumov, B. A.; Morfill, G. E.; Samsonov, D.

    2007-01-05

    We propose a simple method to determine the local coupling strength {gamma} experimentally, by linking the individual particle dynamics with the local density and crystal structure of a 2D plasma crystal. By measuring particle trajectories with high spatial and temporal resolution we obtain the first maps of {gamma} and temperature at individual particle resolution. We employ numerical simulations to test this new method, and discuss the implications to characterize strongly coupled systems.

  18. Quantum states with strong positive partial transpose

    SciTech Connect

    Chruscinski, Dariusz; Jurkowski, Jacek; Kossakowski, Andrzej

    2008-02-15

    We construct a large class of bipartite M x N quantum states which defines a proper subset of states with positive partial transposes (PPTs). Any state from this class has PPT but the positivity of its partial transposition is recognized with respect to canonical factorization of the original density operator. We propose to call elements from this class states with strong positive partial transposes (SPPTs). We conjecture that all SPPT states are separable.

  19. Strong coupling QED with two fermionic flavors

    SciTech Connect

    Wang, K.C.

    1990-11-01

    We report the recent results of our simulation of strong coupling QED, with non-compact action, on lattices 10{sup 4} and 16{sup 4}. Since we are dealing with two staggered fermionic flavors, we use hybrid algorithm to do the simulation. In addition to the measurement of the chiral order parameter {l angle}{bar {psi}}{psi}{r angle}, we also measure magnetic monopole susceptibility, {chi}, throughout the region of chiral transition. 6 refs., 6 figs.

  20. Bose polarons in the strongly interacting regime

    NASA Astrophysics Data System (ADS)

    Kedar, Dhruv; Hu, Ming-Guang; van de Graaff, Michael; Corson, John; Cornell, Eric; Jin, Deborah

    2016-05-01

    Impurities immersed in and interacting with a Bose-Einstein condensate (BEC) are predicted to form quasiparticle excitations called Bose polarons. I will present experimental evidence of Bose polarons in cold atoms obtained using radio-frequency spectroscopy to measure the excitation spectrum of fermionic K-40 impurities interacting with a BEC of Rb-87 atoms. We use an interspecies Feshbach resonance to tune the interactions between the impurities and the bosons, and we take data in the strongly interacting regime.

  1. NON-PARAMETRIC ESTIMATION UNDER STRONG DEPENDENCE.

    PubMed

    Zhao, Zhibiao; Zhang, Yiyun; Li, Runze

    2014-01-01

    We study non-parametric regression function estimation for models with strong dependence. Compared with short-range dependent models, long-range dependent models often result in slower convergence rates. We propose a simple differencing-sequence based non-parametric estimator that achieves the same convergence rate as if the data were independent. Simulation studies show that the proposed method has good finite sample performance.

  2. Concepts in strong Langmuir turbulence theory

    SciTech Connect

    DuBois, D.F.; Rose, H.A.

    1990-01-01

    Some of the basic concepts of strong Langmuir turbulence (SLT) theory are reviewed. In SLT system, a major fraction of the turbulent energy is carried by local, time-dependent, nonlinear excitations called cavitons. Modulational instability, localization of Langmuir fields by density fluctuations, caviton nucleation, collapse, and burnout and caviton correlations are reviewed. Recent experimental evidence will be presented for SLT phenomena in the interaction of powerful HF waves with the ionosphere and in laser-plasma interaction experiments. 38 refs., 11 figs.

  3. Relativistically modulational instability by strong Langmuir waves

    SciTech Connect

    Liu, X. L.; Liu, S. Q.; Li, X. Q.

    2012-09-15

    Based on the set of nonlinear coupling equations, which has considered the relativistic effects of electrons, modulational instability by strong Langmuir waves has been investigated in this paper. Both the characteristic scale and maximum growth rate of the Langmuir field will enhance with the increase in the electron relativistic effect. The numerical results indicate that longitudinal perturbations induce greater instability than transverse perturbations do, which will lead to collapse and formation of the pancake-like structure.

  4. Inflationary magnetogenesis without the strong coupling problem

    SciTech Connect

    Ferreira, Ricardo J.Z.; Jain, Rajeev Kumar; Sloth, Martin S. E-mail: jain@cp3.dias.sdu.dk

    2013-10-01

    The simplest gauge invariant models of inflationary magnetogenesis are known to suffer from the problems of either large backreaction or strong coupling, which make it difficult to self-consistently achieve cosmic magnetic fields from inflation with a field strength larger than 10{sup −32}G today on the Mpc scale. Such a strength is insufficient to act as seed for the galactic dynamo effect, which requires a magnetic field larger than 10{sup −20}G. In this paper we analyze simple extensions of the minimal model, which avoid both the strong coupling and back reaction problems, in order to generate sufficiently large magnetic fields on the Mpc scale today. First we study the possibility that the coupling function which breaks the conformal invariance of electromagnetism is non-monotonic with sharp features. Subsequently, we consider the effect of lowering the energy scale of inflation jointly with a scenario of prolonged reheating where the universe is dominated by a stiff fluid for a short period after inflation. In the latter case, a systematic study shows upper bounds for the magnetic field strength today on the Mpc scale of 10{sup −13}G for low scale inflation and 10{sup −25}G for high scale inflation, thus improving on the previous result by 7-19 orders of magnitude. These results are consistent with the strong coupling and backreaction constraints.

  5. Cosmological test using strong gravitational lensing systems

    NASA Astrophysics Data System (ADS)

    Yuan, C. C.; Wang, F. Y.

    2015-09-01

    As one of the probes of universe, strong gravitational lensing systems allow us to compare different cosmological models and constrain vital cosmological parameters. This purpose can be reached from the dynamic and geometry properties of strong gravitational lensing systems, for instance, time-delay Δτ of images, the velocity dispersion σ of the lensing galaxies and the combination of these two effects, Δτ/σ2. In this paper, in order to carry out one-on-one comparisons between ΛCDM universe and Rh = ct universe, we use a sample containing 36 strong lensing systems with the measurement of velocity dispersion from the Sloan Lens Advanced Camera for Surveys (SLACS) and Lens Structure and Dynamic survey (LSD) survey. Concerning the time-delay effect, 12 two-image lensing systems with Δτ are also used. In addition, Monte Carlo simulations are used to compare the efficiency of the three methods as mentioned above. From simulations, we estimate the number of lenses required to rule out one model at the 99.7 per cent confidence level. Comparing with constraints from Δτ and the velocity dispersion σ, we find that using Δτ/σ2 can improve the discrimination between cosmological models. Despite the independence tests of these methods reveal a correlation between Δτ/σ2 and σ, Δτ/σ2 could be considered as an improved method of σ if more data samples are available.

  6. Diphotons, new vacuum angles, and strong CP

    DOE PAGES

    Draper, Patrick; McKeen, David

    2016-04-20

    The Standard Model contains a well-understood, natural, spin-0 diphoton resonance: the π0. Numerous studies have pointed out that the hint of a new diphoton resonance at 750 GeV could be a pion analog, identified with the pseudo-Nambu-Goldstone boson of a chiral symmetry spontaneously broken by new strong dynamics at the TeV scale. These “hypercolor” models are generically expected to violate parity through a topological angle θ~. We discuss the physics of θ~ and its impact on the phenomenology of the new sector. We also describe some of the theoretical implications of a nonzero θ~. In particular, θ~ can generate anmore » O(1) threshold correction to the QCD vacuum angle θ near the TeV scale, sharply constraining ultraviolet solutions to the strong CP problem. Furthermore, finding that θ~ is small may be interpreted as evidence in favor of UV solutions to strong CP, particularly those based on spontaneously broken P or CP symmetries.« less

  7. Diphotons, new vacuum angles, and strong CP

    SciTech Connect

    Draper, Patrick; McKeen, David

    2016-04-20

    The Standard Model contains a well-understood, natural, spin-0 diphoton resonance: the π0. Numerous studies have pointed out that the hint of a new diphoton resonance at 750 GeV could be a pion analog, identified with the pseudo-Nambu-Goldstone boson of a chiral symmetry spontaneously broken by new strong dynamics at the TeV scale. These “hypercolor” models are generically expected to violate parity through a topological angle θ~. We discuss the physics of θ~ and its impact on the phenomenology of the new sector. We also describe some of the theoretical implications of a nonzero θ~. In particular, θ~ can generate an O(1) threshold correction to the QCD vacuum angle θ near the TeV scale, sharply constraining ultraviolet solutions to the strong CP problem. Furthermore, finding that θ~ is small may be interpreted as evidence in favor of UV solutions to strong CP, particularly those based on spontaneously broken P or CP symmetries.

  8. A Strong Merger Shock in Abell 665

    NASA Technical Reports Server (NTRS)

    Dasadia, S.; Sun, M.; Sarazin, C.; Morandi, A.; Markevitch, M.; Wik, D.; Feretti, L.; Giovannini, G.; Govoni, F.

    2016-01-01

    Deep (103 ks) Chandra observations of Abell 665 have revealed rich structures in this merging galaxy cluster, including a strong shock and two cold fronts. The newly discovered shock has a Mach number of M =?3.0 +/- 0.6, propagating in front of a cold disrupted cloud. This makes Abell 665 the second cluster, after the Bullet cluster, where a strong merger shock of M is approximately 3 has been detected. The shock velocity from jump conditions is consistent with (2.7 +/- 0.7) × 10(exp 3) km s(exp -1). The new data also reveal a prominent southern cold front with potentially heated gas ahead of it. Abell 665 also hosts a giant radio halo. There is a hint of diffuse radio emission extending to the shock at the north, which needs to be examined with better radio data. This new strong shock provides a great opportunity to study the reacceleration model with the X-ray and radio data combined.

  9. Cosmology with Strong-lensing Systems

    NASA Astrophysics Data System (ADS)

    Cao, Shuo; Biesiada, Marek; Gavazzi, Raphaël; Piórkowska, Aleksandra; Zhu, Zong-Hong

    2015-06-01

    In this paper, we assemble a catalog of 118 strong gravitational lensing systems from the Sloan Lens ACS Survey, BOSS emission-line lens survey, Lens Structure and Dynamics, and Strong Lensing Legacy Survey and use them to constrain the cosmic equation of state. In particular, we consider two cases of dark energy phenomenology: the XCDM model, where dark energy is modeled by a fluid with constant w equation-of-state parameter, and in the Chevalier-Polarski-Linder (CPL) parameterization, where w is allowed to evolve with redshift, w(z)={{w}0}+{{w}1}\\frac{z}{1 + z} . We assume spherically symmetric mass distribution in lensing galaxies, but we relax the rigid assumption of the SIS model in favor of a more general power-law index γ, also allowing it to evolve with redshifts γ (z). Our results for the XCDM cosmology show agreement with values (concerning both w and γ parameters) obtained by other authors. We go further and constrain the CPL parameters jointly with γ (z). The resulting confidence regions for the parameters are much better than those obtained with a similar method in the past. They are also showing a trend of being complementary to the Type Ia supernova data. Our analysis demonstrates that strong gravitational lensing systems can be used to probe cosmological parameters like the cosmic equation of state for dark energy. Moreover, they have a potential to judge whether the cosmic equation of state evolved with time or not.

  10. Quantum Symmetries and Strong Haagerup Inequalities

    NASA Astrophysics Data System (ADS)

    Brannan, Michael

    2012-04-01

    In this paper, we consider families of operators {\\{x_r\\}_{r in Λ}} in a tracial C*-probability space {({mathcal{A}}, \\varphi)} , whose joint *-distribution is invariant under free complexification and the action of the hyperoctahedral quantum groups {\\{H_n^+\\}_{n in mathbb {N}}} . We prove a strong form of Haagerup's inequality for the non-self-adjoint operator algebra {{mathcal{B}}} generated by {\\{x_r\\}_{r in Λ}} , which generalizes the strong Haagerup inequalities for *-free R-diagonal families obtained by Kemp-Speicher (J Funct Anal 251:141-173, 2007). As an application of our result, we show that {{mathcal{B}}} always has the metric approximation property (MAP). We also apply our techniques to study the reduced C*-algebra of the free unitary quantum group {U_n^+} . We show that the non-self-adjoint subalgebra {{mathcal{B}}_n} generated by the matrix elements of the fundamental corepresentation of {U_n^+} has the MAP. Additionally, we prove a strong Haagerup inequality for {{mathcal{B}}_n} , which improves on the estimates given by Vergnioux's property RD (Vergnioux in J Oper Theory 57:303-324, 2007).

  11. Systematic errors in strong lens modeling

    NASA Astrophysics Data System (ADS)

    Johnson, Traci Lin; Sharon, Keren; Bayliss, Matthew B.

    2015-08-01

    The lensing community has made great strides in quantifying the statistical errors associated with strong lens modeling. However, we are just now beginning to understand the systematic errors. Quantifying these errors is pertinent to Frontier Fields science, as number counts and luminosity functions are highly sensitive to the value of the magnifications of background sources across the entire field of view. We are aware that models can be very different when modelers change their assumptions about the parameterization of the lensing potential (i.e., parametric vs. non-parametric models). However, models built while utilizing a single methodology can lead to inconsistent outcomes for different quantities, distributions, and qualities of redshift information regarding the multiple images used as constraints in the lens model. We investigate how varying the number of multiple image constraints and available redshift information of those constraints (ex., spectroscopic vs. photometric vs. no redshift) can influence the outputs of our parametric strong lens models, specifically, the mass distribution and magnifications of background sources. We make use of the simulated clusters by M. Meneghetti et al. and the first two Frontier Fields clusters, which have a high number of multiply imaged galaxies with spectroscopically-measured redshifts (or input redshifts, in the case of simulated clusters). This work will not only inform upon Frontier Field science, but also for work on the growing collection of strong lensing galaxy clusters, most of which are less massive and are capable of lensing a handful of galaxies, and are more prone to these systematic errors.

  12. Quantum processes in strong magnetic fields

    NASA Technical Reports Server (NTRS)

    Canuto, V.

    1975-01-01

    Quantum-mechanical processes that occur in a piece of matter embedded in a magnetic field with a strength of the order of 10 to the 13th power G are described which either are entirely due to the presence of the field or become modified because of it. The conversion of rotational energy into electromagnetic energy in pulsars is analyzed as a mechanism for producing such a field, and it is shown that a strong magnetic field is not sufficient for quantum effects to play a significant role; in addition, the density must be adjusted to be as low as possible. The pressure and energy density of a free electron gas in a uniform magnetic field are evaluated, neutron beta-decay in the presence of a strong field is examined, and the effect of such a field on neutrino reactions is discussed. The thermal history of a neutron star is studied, and it is concluded that a strong magnetic field helps to increase the cooling rate of the star by producing new channels through which neutrinos can carry away energy.

  13. Engaging Military Fathers in a Reflective Parenting Program: Lessons from Strong Families Strong Forces

    ERIC Educational Resources Information Center

    DeVoe, Ellen R.; Paris, Ruth

    2015-01-01

    Through Strong Families Strong Forces, a reflective parenting program for military families with young children, we were privileged to work with contemporary military fathers who served in the post-9/11 conflicts in Afghanistan and Iraq. Due to this work, the authors gained valuable insight into the complexity of fathering during wartime, the…

  14. Is strong reciprocity really strong in the lab, let alone in the real world?

    PubMed

    Güney, Şule; Newell, Ben R

    2012-02-01

    We argue that standard experiments supporting the existence of "strong reciprocity" do not represent many cooperative situations outside the laboratory. More representative experiments that incorporate "earned" rather than "windfall" wealth also do not provide evidence for the impact of strong reciprocity on cooperation in contemporary real-life situations or in evolutionary history, supporting the main conclusions of the target article.

  15. Prevention of strong earthquakes: Goal or utopia?

    NASA Astrophysics Data System (ADS)

    Mukhamediev, Sh. A.

    2010-11-01

    In the present paper, we consider ideas suggesting various kinds of industrial impact on the close-to-failure block of the Earth’s crust in order to break a pending strong earthquake (PSE) into a number of smaller quakes or aseismic slips. Among the published proposals on the prevention of a forthcoming strong earthquake, methods based on water injection and vibro influence merit greater attention as they are based on field observations and the results of laboratory tests. In spite of this, the cited proofs are, for various reasons, insufficient to acknowledge the proposed techniques as highly substantiated; in addition, the physical essence of these methods has still not been fully understood. First, the key concept of the methods, namely, the release of the accumulated stresses (or excessive elastic energy) in the source region of a forthcoming strong earthquake, is open to objection. If we treat an earthquake as a phenomenon of a loss in stability, then, the heterogeneities of the physicomechanical properties and stresses along the existing fault or its future trajectory, rather than the absolute values of stresses, play the most important role. In the present paper, this statement is illustrated by the classical examples of stable and unstable fractures and by the examples of the calculated stress fields, which were realized in the source regions of the tsunamigenic earthquakes of December 26, 2004 near the Sumatra Island and of September 29, 2009 near the Samoa Island. Here, just before the earthquakes, there were no excessive stresses in the source regions. Quite the opposite, the maximum shear stresses τmax were close to their minimum value, compared to τmax in the adjacent territory. In the present paper, we provide quantitative examples that falsify the theory of the prevention of PSE in its current form. It is shown that the measures for the prevention of PSE, even when successful for an already existing fault, can trigger or accelerate a catastrophic

  16. Gutzwiller approximation in strongly correlated electron systems

    NASA Astrophysics Data System (ADS)

    Li, Chunhua

    Gutzwiller wave function is an important theoretical technique for treating local electron-electron correlations nonperturbatively in condensed matter and materials physics. It is concerned with calculating variationally the ground state wave function by projecting out multi-occupation configurations that are energetically costly. The projection can be carried out analytically in the Gutzwiller approximation that offers an approximate way of calculating expectation values in the Gutzwiller projected wave function. This approach has proven to be very successful in strongly correlated systems such as the high temperature cuprate superconductors, the sodium cobaltates, and the heavy fermion compounds. In recent years, it has become increasingly evident that strongly correlated systems have a strong propensity towards forming inhomogeneous electronic states with spatially periodic superstrutural modulations. A good example is the commonly observed stripes and checkerboard states in high- Tc superconductors under a variety of conditions where superconductivity is weakened. There exists currently a real challenge and demand for new theoretical ideas and approaches that treats strongly correlated inhomogeneous electronic states, which is the subject matter of this thesis. This thesis contains four parts. In the first part of the thesis, the Gutzwiller approach is formulated in the grand canonical ensemble where, for the first time, a spatially (and spin) unrestricted Gutzwiller approximation (SUGA) is developed for studying inhomogeneous (both ordered and disordered) quantum electronic states in strongly correlated electron systems. The second part of the thesis applies the SUGA to the t-J model for doped Mott insulators which led to the discovery of checkerboard-like inhomogeneous electronic states competing with d-wave superconductivity, consistent with experimental observations made on several families of high-Tc superconductors. In the third part of the thesis, new

  17. Surfactant proteins A and D in the genital tract of mares.

    PubMed

    Kankavi, Orhan; Ata, Ayhan; Gungor, Orsan

    2007-04-01

    The presence of surface-active material in the lung alveolus has been known for several decades as being essential for normal lung function. Surfactant is essential for reducing the surface tension at the alveolar air-liquid interface. Pulmonary surfactant is composed of 90% lipids and 10% proteins. There are four non-serum proteins surfactant protein-A (SP-A), surfactant protein-B (SP-B), surfactant protein-C (SP-C) and surfactant protein-D (SP-D) named in chronologic order of discovery. Lung SP-A and SP-D belong to a family of collagen-containing C-type lectin family called collectins. The host defence and controlling inflammatory processes of the lung are the major functions of SP-A and SP-D. SP-A and SP-D were originally demonstrated in alveolar type II cells, but recent studies have shown extrapulmonary expression of SP-A and SP-D indicating systemic roles of these proteins. Present study describes the presence of SP-A and SP-D in the mare genital tract, vulva, vagina, ovarium, uterus and tuba uterina using immunohistochemistry and Western blotting. The aim of this study was to characterize surfactant proteins in terms of: (i) whether surfactant proteins were present in the various structures of the mare genital system, (ii) if so, identifying and locating the surfactant proteins and finally (iii) determining the differences from those previously characterized for the lung. Although beyond the scope of this report, it is recognized that there are also some potential implications for better defining the reproductive defence mechanisms in mare. Therefore, genital system organs and tissues from mares were examined. We were able to show that proteins reactive with surfactant-specific antibodies were present in the mare genital tract. Thus, surfactant proteins are present not in just lamellar bodies associated with lung, but also genital system of mare.

  18. Strong correlations in actinide redox reactions

    NASA Astrophysics Data System (ADS)

    Horowitz, S. E.; Marston, J. B.

    2011-02-01

    Reduction-oxidation (redox) reactions of the redox couples An(VI)/An(V), An(V)/An(IV), and An(IV)/An(III), where An is an element in the family of early actinides (U, Np, and Pu), as well as Am(VI)/Am(V) and Am(V)/Am(III), are modeled by combining density functional theory with a generalized Anderson impurity model that accounts for the strong correlations between the 5f electrons. Diagonalization of the Anderson impurity model yields improved estimates for the redox potentials and the propensity of the actinide complexes to disproportionate.

  19. Vacuum orientations in strong CP violation

    SciTech Connect

    Huang, Zheng; Viswanathan, K.S.; Wu, Dan-di

    1991-12-01

    We study the QCD vacuum orientation angles in correlation with the strong CP phases. A vacuum alignment equation of the dynamical chiral symmetry breaking is derived based on the anomalous Ward identity. It is emphasized that a chiral rotation of the quark field causes a change of the vacuum orientation and a change in the definition of the light pseudoscalar generators. As an illustration of the idea, {eta} {yields} 2{pi} decays are carefully studied in different chiral frames and shown to be independent of. chiral rotations.

  20. Obama Indicates Strong Support for Science

    NASA Astrophysics Data System (ADS)

    Showstack, Randy

    2009-05-01

    In remarks delivered at the U.S. National Academy of Sciences (NAS) annual meeting on 27 April, U.S. President Barack Obama indicated his administration's strong support for science and for pursuing a clean energy economy. He also announced a goal that the United States “will devote more than 3% of our [gross domestic product] to research and development.” “This represents the largest commitment to scientific research and innovation in American history,” Obama said, noting that the American Recovery and Reinvestment Act already is providing the nation with its largest single boost to investment in basic research.

  1. Fundamental Structure of Matter and Strong Interaction

    SciTech Connect

    Jian-Ping Chen

    2011-11-01

    More than 99% of the visible matter in the universe are the protons and neutrons. Their internal structure is mostly governed by the strong interaction. Understanding their internal structure in terms of fundamental degrees-of-freedom is one of the most important subjects in modern physics. Worldwide efforts in the last few decades have lead to numerous surprises and discoveries, but major challenges still remain. An overview of the progress will be presented with a focus on the recent studies of the proton and neutron's electromagnetic and spin structure. Future perspectives will be discussed.

  2. Strong Interaction Studies with PANDA at FAIR

    NASA Astrophysics Data System (ADS)

    Schönning, Karin

    2016-10-01

    The Facility for Antiproton and Ion Research (FAIR) in Darmstadt, Germany, provides unique possibilities for a new generation of nuclear-, hadron- and atomic physics experiments. The future PANDA experiment at FAIR will offer a broad physics programme with emphasis on different aspects of hadron physics. Understanding the strong interaction in the perturbative regime remains one of the greatest challenges in contemporary physics and hadrons provide several important keys. In these proceedings, PANDA will be presented along with some high-lights of the planned physics programme.

  3. Hypervelocity Plasmas with Strong MHD (Magnetohydrodynamic) Interactions.

    DTIC Science & Technology

    1984-12-01

    ARD-Ai5S 867 HYPERVELOCITY PLASMAS WITH STRONG NHD j/j (MAGNETOHYDRODYNANIC) INTERRCTIONS(U) STD RESEARCH CORP ARCADIA CA S T DEMETRIADES FT AL DEC...MIRCP RSLTO-TS HR NAINLBUEUO SADRS-16- -ArO’ mi -T7- (7 % STD RESEARCH CORPORATION POST OFFICE OX ’C’ ARC ADIA, CALIFORNIA 91006 LTf.LEPHONE! (213...Covered: 1 June 1983 -31 May 1984 December 1984 STD Research Corporation P.O. Box "’C" Arcadia, California 91006 Appi-u ’, 2 I~t or1 ’Pub I rege

  4. Understanding strongly coupling magnetism from holographic duality

    NASA Astrophysics Data System (ADS)

    Cai, Rong-Gen; Yang, Run-Qiu

    2016-07-01

    The unusual magnetic materials are significant in both science and technology. However, because of the strongly correlated effects, it is difficult to understand their novel properties from theoretical aspects. Holographic duality offers a new approach to understanding such systems from gravity side. This paper will give a brief review of our recent works on the applications of holographic duality in understanding unusual magnetic materials. Some quantitative comparision between holographic results and experimental data will be shown and some predictions from holographic duality models will be discussed.

  5. Strong correlations in actinide redox reactions.

    PubMed

    Horowitz, S E; Marston, J B

    2011-02-14

    Reduction-oxidation (redox) reactions of the redox couples An(VI)/An(V), An(V)/An(IV), and An(IV)/An(III), where An is an element in the family of early actinides (U, Np, and Pu), as well as Am(VI)/Am(V) and Am(V)/Am(III), are modeled by combining density functional theory with a generalized Anderson impurity model that accounts for the strong correlations between the 5f electrons. Diagonalization of the Anderson impurity model yields improved estimates for the redox potentials and the propensity of the actinide complexes to disproportionate.

  6. Bose Polarons in the Strongly Interacting Regime

    NASA Astrophysics Data System (ADS)

    Hu, Ming-Guang; Van de Graaff, Michael J.; Kedar, Dhruv; Corson, John P.; Cornell, Eric A.; Jin, Deborah S.

    2016-07-01

    When an impurity is immersed in a Bose-Einstein condensate, impurity-boson interactions are expected to dress the impurity into a quasiparticle, the Bose polaron. We superimpose an ultracold atomic gas of 87Rb with a much lower density gas of fermionic 40 impurities. Through the use of a Feshbach resonance and radio-frequency spectroscopy, we characterize the energy, spectral width, and lifetime of the resultant polaron on both the attractive and the repulsive branches in the strongly interacting regime. The width of the polaron in the attractive branch is narrow compared to its binding energy, even as the two-body scattering length diverges.

  7. SENTINEL-1 Image Matching Using Strong Scatters

    NASA Astrophysics Data System (ADS)

    Ghannadi, M. A.; Saadatseresht, M.; Motagh, M.

    2015-12-01

    The availability of new radar spaceborne sensors offers new interesting potentialities for the geomatics application: spatial and temporal change detection, generation of Digital Elevation Model(DEM) using radargrametry and interferometry. Since the start of the sentinel-1 mission to take images from different regions all over the world, the ability to use these images in variety domains has been treasured. This paper suggests a method for image matching using strong scatters. all the experiments are done on sentinel-1 stereo images from Jam, Bushehr, Iran.

  8. Why so strong for the lotus leaf?

    NASA Astrophysics Data System (ADS)

    Guo, Zhiguang; Liu, Weimin; Su, Bao-Lian

    2008-11-01

    The authors discussed the potential reasons why the lotus leaf is so strong by means of scanning electron microscopy (SEM). The results showed that the good mechanical properties of lotus leaf should be attributed to its architecture, such as paralleled microtubes structure, umbrellalike structure, and hierarchically layered hexagon structure. The important observation from this work is that the surface of the rear face of the lotus leaf seems to be constituted by the layers of hexagons whose hierarchical pilling up of size decreases as we go deeper from surface. This is a typical fractal-like phenomenon.

  9. Strong intrinsic mixing in vortex magnetic fields.

    PubMed

    Martin, James E; Shea-Rohwer, Lauren; Solis, Kyle J

    2009-07-01

    We report a method of magnetic mixing wherein a "vortex" magnetic field applied to a suspension of magnetic particles creates strong homogeneous mixing throughout the fluid volume. Experiments designed to elucidate the microscopic mechanism of mixing show that the torque is quadratic in the field, decreases with field frequency, and is optimized at a vortex field angle of approximately 55 degrees . Theory and simulations indicate that the field-induced formation of volatile particle chains is responsible for these phenomena. This technique has applications in microfluidic devices and is ideally suited to applications such as accelerating the binding of target biomolecules to biofunctionalized magnetic microbeads.

  10. Determination of Lipid-Protein Interactions in Lung Surfactants Using Computer Simulations and Structural Bioinformatics.

    NASA Astrophysics Data System (ADS)

    Kaznessis, Yiannis

    2001-06-01

    Proteins are the primary components of the networks that conduct the flows of mass, energy and information in living organisms. The discovery of the principles of protein structure and function allows the development of design rules for biological activities. The microscopic nature of the operating mechanisms of protein activity, and the vast complexity of the networks of interaction call for the employment of powerful computational methodologies that can decipher the physicochemical and evolutionary principles underlying protein structure and function. An example will be presented that reflects the strength of computational approaches. Atomistic molecular dynamics simulations and structural bioinformatics tools are employed to investigate the interactions between the first 25 N-terminal residues of surfactant protein B (SP-B 1-25) and the lipid components of the lung surfactant (LS). An understanding of the molecular level interactions between the LS components is essential for the establishment of design rules for the development of synthetic LS and the treatment of the neonatal respiratory distress syndrome, which results from deficiency or inactivation of LS.

  11. Multimode Strong Coupling in Circuit QED

    NASA Astrophysics Data System (ADS)

    Sundaresan, Neereja; Liu, Yanbing; Sadri, Darius; Szocs, Laszlo; Underwood, Devin; Malekakhlagh, Moein; Tureci, Hakan; Houck, Andrew

    We present experimental and theoretical studies in the multimode strong coupling (MMSC) regime of cavity quantum electrodynamics (QED). In MMSC, a single atom is simultaneously coupled to a large, but discrete, number of cavity harmonics, with atom-mode coupling strengths comparable to the free spectral range (FSR). This regime is readily accessible in circuit QED, by strongly coupling a transmon qubit to a low fundamental frequency microwave cavity. We present some key results from our original experiment (PRX 5, 021035, 2015), in which a transmon qubit, resonant with the 75th harmonic of a 90 MHz cavity, reached qubit-mode coupling strengths exceeding 30MHz. When this system is coherently driven, we observed complex multimode fluorescence, with the notable formation of ultra-narrow linewidths. To better understand these unique features of multimode resonance fluorescence we developed a quantum formalism, which attributes the spectral linewidth narrowing to the correlated spontaneous emission of doubly dressed states. Finally we will share preliminary experimental results from our continuing study of MMSC, this time from a system where qubit-mode coupling strengths approach and even exceed the FSR.

  12. Proton tautomerism for strong polarization switching

    NASA Astrophysics Data System (ADS)

    Horiuchi, Sachio; Kobayashi, Kensuke; Kumai, Reiji; Ishibashi, Shoji

    2017-02-01

    Ferroelectrics based on proton tautomerism are promising in low-field and above-room-temperature operations. Here seven organic ferroelectric crystals are examined to search for efficient switching of strong spontaneous polarization on proton tautomerism. Solution-grown crystals exhibit strong pinning of ferroelectric domain walls, but excellent switching performance is awakened by depinning domain walls under thermal annealing and/or repetitive bipolar pulses with a high voltage. Compared with ferroelectric polymers such as polyvinylidefluoride, the optimized polarizations are comparable or stronger in magnitude whereas the coercive fields are two orders of magnitude weaker. The polarization of croconic acid, in particular, breaks its own record for organic systems in increasing from 21 to 30 μC cm-2 and now exceeds those of some commercial ferroelectric materials such as SrBi2Ta2O9 and BaTiO3. Optimization reduces the discrepancy of the spontaneous polarization with the results of the first-principles calculations to less than 15%. The cooperative roles of proton transfer and π-bond switching are discussed by employing the point-charge model and hydrogen-bond geometry.

  13. Coping with strongly coupled string theory

    NASA Astrophysics Data System (ADS)

    Banks, Tom; Dine, Michael

    1994-12-01

    String theory, if it describes nature, is probably strongly coupled. As a result, one might despair of making any statements about the theory. In the framework of a set of clearly spelled out assumptions, we show that this is not necessarily the case. Certain discrete gauge symmetries, combined with supersymmetry, tightly constrain the form of the effective action. Among our assumptions are that the true ground state can be obtained from some perturbative ground state by varying the coupling, and that the actual numerical value of the low energy field-theoretic coupling g2/4π is small. It follows that the low energy theory is approximately supersymmetric; corrections to the superpotential and gauge coupling function are small, while corrections to the Kahler potential are large; the spectrum of light particles is the same at strong as at weak coupling. We survey the phenomenological consequences of this viewpoint. We also note that the string axion can serve as a QCD axion in this framework (modulo cosmological problems).

  14. The Athens Acropolis Strong Motion Array

    NASA Astrophysics Data System (ADS)

    Kalogeras, I. S.; Evangelidis, C. P.; Melis, N. S.; Boukouras, K.

    2012-04-01

    During the last decades, extensive restoration works through a dedicated "Acropolis Restoration Service" (YSMA) take place in the Acropolis, the greatest sanctuary of ancient Athens. Since 2008, a permanent strong motion array was deployed by the Institute of Geodynamics, National Observatory of Athens (NOA-IG) in collaboration with YSMA. Free field installations were decided at sites showing various characteristics, aiming to investigate differences in geotechnical properties as well as the structure response of Parthenon itself. The installation phase is presented, with the techniques used to overcome difficulties (i.e. extreme weather conditions, power and communication limitations, restoration works and visitors) and the special care taken for the specific archaeological site. Furthermore, indicative examples of seismic events recorded by the array are analyzed and the complexity of the hill and the monument is made apparent. Among them, the long distance events of Tohoku, Japan 2010 and Van, Turkey 2011, some regional moderate earthquakes in Greece and some weak earthquakes from the vicinity. Continuous ambient noise monitoring using PQLX software gives some first indicative results, showing a variety of characteristics at installation sites. Finally, further developments and future steps are presented such as: the extension of the array, the integration of seismic data within the GIS platform of YSMA at the site and the use of strong motion records, in conjunction with data from other monitoring systems operating in Acropolis for the study of specific monuments.

  15. Strong interaction physics from hadronic atoms

    NASA Astrophysics Data System (ADS)

    Batty, C. J.; Friedman, E.; Gal, A.

    1997-08-01

    Hadronic atoms provide a unique laboratory for studying strong interactions and nuclear medium effects at zero kinetic energy. Previous results from analyses of strong-interaction data consisting of level shifts, widths and yields in π-, K -, p¯ and ∑ - atoms are reviewed. Recent results from fits to comprehensive sets of data in terms of density-dependent optical potentials that respect the low-density limit, where the interaction tends to the free hadron nucleon value, are discussed. The importance of using realistic nuclear density distributions is highlighted. The introduction of density dependence in most cases significantly improves the fit to the data and leads to some novel results. For K - atoms, a substantial attraction of order 200 MeV in nuclear matter is suggested, with interesting repercussions for K¯ condensation and the evolution of strangeness in high-density stars. For p¯ atoms it is found that a reasonable p-wave strength can be accommodated in the fitted optical potential, in agreement with the energy dependence observed for some low-energy p¯N reactions. For ∑ - atoms, the fitted potential becomes repulsive inside the nucleus, implying that Σ hyperons generally do not bind in nuclei in agreement with recent measurements. This repulsion significantly affects calculated masses of neutron stars.

  16. Caviton dynamics in strong Langmuir turbulence

    SciTech Connect

    DuBois, D.; Rose, H.A.; Russell, D.

    1989-01-01

    Recent studies based on long time computer simulations of Langmuir turbulence as described by Zakharov's model will be reviewed. These show that for strong to moderate ion sound samping the turbulent energy is dominantly in nonlinear ''caviton'' excitations which are localized in space and time. A local caviton model will be presented which accounts for the nucleation-collapse-burnout cycles of individual cavitons as well as their space-time correlations. This model is in detailed agreement with many features of the electron density fluctuation spectra in the ionosphere modified by powerful hf waves as measured by incoherent scatter radar. Recently such observations have verified a prediction of the theory that ''free'' Langmuir waves are emitted in the caviton collapse process. These observations and theoretical considerations also strongly imply that cavitons in the heated ionosphere, under certain conditions, evolve to states in which they are ordered in space and time. The sensitivity of the high frequency Langmuir field dynamics to the low frequency ion density fluctuations and the related caviton nucleation process will be discussed. 40 refs., 19 figs.

  17. The evolution of strong reproductive isolation.

    PubMed

    Barton, Nicholas H; de Cara, Maria Angeles Rodriguez

    2009-05-01

    Felsenstein distinguished two ways by which selection can directly strengthen isolation. First, a modifier that strengthens prezygotic isolation can be favored everywhere. This fits with the traditional view of reinforcement as an adaptation to reduce deleterious hybridization by strengthening assortative mating. Second, selection can favor association between different incompatibilities, despite recombination. We generalize this "two allele" model to follow associations among any number of incompatibilities, which may include both assortment and hybrid inviability. Our key argument is that this process, of coupling between incompatibilities, may be quite different from the usual view of reinforcement: strong isolation can evolve through the coupling of any kind of incompatibility, whether prezygotic or postzygotic. Single locus incompatibilities become coupled because associations between them increase the variance in compatibility, which in turn increases mean fitness if there is positive epistasis. Multiple incompatibilities, each maintained by epistasis, can become coupled in the same way. In contrast, a single-locus incompatibility can become coupled with loci that reduce the viability of haploid hybrids because this reduces harmful recombination. We obtain simple approximations for the limits of tight linkage, and strong assortment, and show how assortment alleles can invade through associations with other components of reproductive isolation.

  18. Hofstadter's Butterfly in the strongly interacting regime

    NASA Astrophysics Data System (ADS)

    Dean, Cory

    2015-03-01

    In 1976, Douglas Hofstadter predicted that in the presence of both a strong magnetic field, and a spatially varying periodic potential, Bloch electrons confined to a 2D quantum well exhibit a self-similar fractal energy spectrum known as the ``Hofstadter's Butterfly.'' In subsequent years, experimental discovery of the quantum Hall effect gave birth to an expansive field of research into 2D electronic systems in the presence of a magnetic field, however, direct confirmation of the fractal spectrum remained elusive. Recently we demonstrated that graphene, in which Bloch electrons can be described by Dirac fermions, provides a new opportunity to investigate this nearly 40 year old problem. In this talk I will discuss the experimental realization of Hofstader's butterfly by exploiting nano-scale interfacial effects between graphene and hexagonal boron nitride substrates, together with application of extremely high magnetic fields. Utilizing newly developed techniques to fabricate ultra-clean graphene devices, I will additionally demonstrate the capability to probe for the first time the effect of strong electron interactions within the fractal Hofstadter spectrum.

  19. Proton tautomerism for strong polarization switching

    PubMed Central

    Horiuchi, Sachio; Kobayashi, Kensuke; Kumai, Reiji; Ishibashi, Shoji

    2017-01-01

    Ferroelectrics based on proton tautomerism are promising in low-field and above-room-temperature operations. Here seven organic ferroelectric crystals are examined to search for efficient switching of strong spontaneous polarization on proton tautomerism. Solution-grown crystals exhibit strong pinning of ferroelectric domain walls, but excellent switching performance is awakened by depinning domain walls under thermal annealing and/or repetitive bipolar pulses with a high voltage. Compared with ferroelectric polymers such as polyvinylidefluoride, the optimized polarizations are comparable or stronger in magnitude whereas the coercive fields are two orders of magnitude weaker. The polarization of croconic acid, in particular, breaks its own record for organic systems in increasing from 21 to 30 μC cm−2 and now exceeds those of some commercial ferroelectric materials such as SrBi2Ta2O9 and BaTiO3. Optimization reduces the discrepancy of the spontaneous polarization with the results of the first-principles calculations to less than 15%. The cooperative roles of proton transfer and π-bond switching are discussed by employing the point-charge model and hydrogen-bond geometry. PMID:28205550

  20. Orientation of llama antibodies strongly increases sensitivity of biosensors.

    PubMed

    Trilling, Anke K; Hesselink, Thamara; van Houwelingen, Adèle; Cordewener, Jan H G; Jongsma, Maarten A; Schoffelen, Sanne; van Hest, Jan C M; Zuilhof, Han; Beekwilder, Jules

    2014-10-15

    Sensitivity of biosensors depends on the orientation of bio-receptors on the sensor surface. The objective of this study was to organize bio-receptors on surfaces in a way that their analyte binding site is exposed to the analyte solution. VHH proteins recognizing foot-and-mouth disease virus (FMDV) were used for making biosensors, and azides were introduced in the VHH to function as bioorthogonal reactive groups. The importance of the orientation of bio-receptors was addressed by comparing sensors with randomly oriented VHH (with multiple exposed azide groups) to sensors with uniformly oriented VHH (with only a single azide group). A surface plasmon resonance (SPR) chip exposing cyclooctyne was reacted to azide functionalized VHH domains, using click chemistry. Comparison between randomly and uniformly oriented bio-receptors showed up to 800-fold increase in biosensor sensitivity. This technique may increase the containment of infectious diseases such as FMDV as its strongly enhanced sensitivity may facilitate early diagnostics.

  1. BOOK REVIEW: Physics of Strongly Coupled Plasma

    NASA Astrophysics Data System (ADS)

    Kraeft, Wolf-Dietrich

    2007-07-01

    Strongly coupled plasmas (or non-ideal plasmas) are multi-component charged many-particle systems, in which the mean value of the potential energy of the system is of the same order as or even higher than the mean value of the kinetic energy. The constituents are electrons, ions, atoms and molecules. Dusty (or complex) plasmas contain still mesoscopic (multiply charged) particles. In such systems, the effects of strong coupling (non-ideality) lead to considerable deviations of physical properties from the corresponding properties of ideal plasmas, i.e., of plasmas in which the mean kinetic energy is essentially larger than the mean potential energy. For instance, bound state energies become density dependent and vanish at higher densities (Mott effect) due to the interaction of the pair with the surrounding particles. Non-ideal plasmas are of interest both for general scientific reasons (including, for example, astrophysical questions), and for technical applications such as inertially confined fusion. In spite of great efforts both experimentally and theoretically, satisfactory information on the physical properties of strongly coupled plasmas is not at hand for any temperature and density. For example, the theoretical description of non-ideal plasmas is possible only at low densities/high temperatures and at extremely high densities (high degeneracy). For intermediate degeneracy, however, numerical experiments have to fill the gap. Experiments are difficult in the region of `warm dense matter'. The monograph tries to present the state of the art concerning both theoretical and experimental attempts. It mainly includes results of the work perfomed in famous Russian laboratories in recent decades. After outlining basic concepts (chapter 1), the generation of plasmas is considered (chapter 2, chapter 3). Questions of partial (chapter 4) and full ionization (chapter 5) are discussed including Mott transition and Wigner crystallization. Electrical and optical

  2. Strong correlations in gravity and biophysics

    NASA Astrophysics Data System (ADS)

    Krotov, Dmitry

    The unifying theme of this dissertation is the use of correlations. In the first part (chapter 2), we investigate correlations in quantum field theories in de Sitter space. In the second part (chapters 3,4,5), we use correlations to investigate a theoretical proposal that real (observed in nature) transcriptional networks of biological organisms are operating at a critical point in their phase diagram. In chapter 2 we study the infrared dependence of correlators in various external backgrounds. Using the Schwinger-Keldysh formalism we calculate loop corrections to the correlators in the case of the Poincare patch and the complete de Sitter space. In the case of the Poincare patch, the loop correction modifies the behavior of the correlator at large distances. In the case of the complete de Sitter space, the loop correction has a strong dependence on the infrared cutoff in the past. It grows linearly with time, suggesting that at some point the correlations become strong and break the symmetry of the classical background. In chapter 3 we derive the signatures of critical behavior in a model organism, the embryo of Drosophila melanogaster. They are: strong correlations in the fluctuations of different genes, a slowing of dynamics, long range correlations in space, and departures from a Gaussian distribution of these fluctuations. We argue that these signatures are observed experimentally. In chapter 4 we construct an effective theory for the zero mode in this system. This theory is different from the standard Landau-Ginsburg description. It contains gauge fields (the result of the broken translational symmetry inside the cell), which produce observable contributions to the two-point function of the order parameter. We show that the behavior of the two-point function for the network of N genes is described by the action of a relativistic particle moving on the surface of the N - 1 dimensional sphere. We derive a theoretical bound on the decay of the correlations and

  3. Strong Dietary Restrictions Protect Drosophila against Anoxia/Reoxygenation Injuries

    PubMed Central

    Vigne, Paul; Tauc, Michel; Frelin, Christian

    2009-01-01

    Background Reoxygenation of ischemic tissues is a major factor that determines the severity of cardiovascular diseases. This paper describes the consequences of anoxia/reoxygenation (A/R) stresses on Drosophila, a useful, anoxia tolerant, model organism. Methodology/Principal Findings Newly emerged adult male flies were exposed to anoxic conditions (<1% O2) for 1 to 6 hours, reoxygenated and their survival was monitored. Results A/R stresses induced a transient increase in mortality which peaked at the time of reoxygenation. Then flies recovered low mortality rates similar to those of control flies. A/R induced mortality was strongly dependent on dietary conditions during the 48 h that preceded anoxia. Well fed flies were anoxia sensitive. Strong dietary restrictions and starvation conditions protected flies against A/R injuries. The tolerance to anoxia was associated to large decreases in glycogen, protein, and ATP contents. During anoxia, anoxia tolerant flies produced more lactate, less phosphate and they maintained more stable ATP levels than anoxia sensitive flies. Moderate dietary restrictions, which increased the longevity of normoxic flies, did not promote resistance to A/R stresses. Diet dependent A/R injuries were still observed in sima loss of function mutants and they were insensitive to dietary rapamycin or resveratrol. AICAR (5-aminoimidazole-4-carboxamide-1-beta-D-ribosefuranoside), an activator AMP kinase decreased A/R injuries. Mutants in the insulin signalling pathway were more anoxia tolerant in a fed state. Conclusion/Significance Long A/R stresses induce a transient increase in mortality in Drosophila. This mortality is highly dependent on dietary conditions prior to the stress. Strong dietary restrictions and starvation conditions protect flies against A/R injuries, probably by inducing a major remodelling of energy metabolism. The results also indicate that mechanistically different responses develop in response to dietary restrictions of

  4. Utilizing Nanofabrication to Construct Strong, Luminescent Materials

    SciTech Connect

    Chen, Wei; Huang, Gang; Lu, Hong B.; McCready, David E.; Joly, Alan G.; Bovin, Jan-Olov

    2006-05-28

    Luminescent materials have been utilized widely in applications from lighting to sensing. The new development of technologies based on luminescence properties requires the materials to have high luminescence efficiency and mechanical strength. In this article, we report the fabrication of luminescent materials possessing high mechanical strength by nanofabrication with polyvinyl alcohol used as a stabilizer or coupling agent. X-ray diffraction and high resolution transmission microscope observations reveal that the nanocomposite sample contains ZnS and ZnO nanoparticles as well as kozoite and sodium nitrate. The mechanical strength and hardness of these nanocomposite materials are higher than polycarbonate and some carbon nanotube reinforced nanocomposites. Strong luminescence is observed in the new nanocomposites and the luminescence intensity does not degrade following up to 30 minutes of X-ray irradiation. Our results indicate that nanofabrication may provide a good method to improve the mechanical strength of luminescent materials for some applications in which high strength luminescent materials are needed.

  5. Strong quantum scarring by local impurities

    NASA Astrophysics Data System (ADS)

    Luukko, Perttu J. J.; Drury, Byron; Klales, Anna; Kaplan, Lev; Heller, Eric J.; Räsänen, Esa

    2016-11-01

    We discover and characterise strong quantum scars, or quantum eigenstates resembling classical periodic orbits, in two-dimensional quantum wells perturbed by local impurities. These scars are not explained by ordinary scar theory, which would require the existence of short, moderately unstable periodic orbits in the perturbed system. Instead, they are supported by classical resonances in the unperturbed system and the resulting quantum near-degeneracy. Even in the case of a large number of randomly scattered impurities, the scars prefer distinct orientations that extremise the overlap with the impurities. We demonstrate that these preferred orientations can be used for highly efficient transport of quantum wave packets across the perturbed potential landscape. Assisted by the scars, wave-packet recurrences are significantly stronger than in the unperturbed system. Together with the controllability of the preferred orientations, this property may be very useful for quantum transport applications.

  6. New strongly deformed proton emitter: 117La

    NASA Astrophysics Data System (ADS)

    Soramel, F.; Guglielmetti, A.; Stroe, L.; Müller, L.; Bonetti, R.; Poli, G. L.; Malerba, F.; Bianchi, E.; Andrighetto, A.; Guo, J. Y.; Li, Z. C.; Maglione, E.; Scarlassara, F.; Signorini, C.; Liu, Z. H.; Ruan, M.; Ivaşcu, M.; Broude, C.; Bednarczyk, P.; Ferreira, L. S.

    2001-03-01

    The decay by proton emission of the 117La nucleus has been studied via the 310 MeV 58Ni+64Zn reaction. The nucleus has two levels that decay to the ground state of 116Ba with Ep=783(6) keV (T1/2=22(5) ms] and Ep=933(10) keV [T1/2=10(5) ms]. Calculations performed for a deformed proton emitter reproduce quite well the experimental results confirming that 117La is strongly deformed (β2~0.3). Spin and parity of the two p-decaying levels have been determined as well: 3/2+ for the ground state and 9/2+ for the Ex=151(12) keV excited state.

  7. Strong Localization of Positive Charge in DNA

    NASA Astrophysics Data System (ADS)

    Uskov, Dmitry; Burin, Alex

    2008-05-01

    The positive charge transfer in a DNA molecule is determined by two main factors: the structure and composition of specific DNA strand, and interaction of a positive charge with the DNA environment. In this letter we present results of microscopic linear response theory for balance of charge transfer reaction in synthetic strands GAGG and GAGGG, where experimental data on the rates of electron hole migration has been reported by Lewis et al Nature, 406, 51-53 (2000). Our theoretical predictions, based on experimental data for the ratio of reaction rates G^+A(G)n<->GA(G)n^+ , n=2,3, suggest that charge in DNA is strongly localized within the single base pair because of the self-induced reorganization of classical environment. The onset of localization has a threshold behavior characteristic to quantum bistability. We also demonstrate that our conclusion does not depend on details of the model.

  8. On a strong coupling property of QCD

    NASA Astrophysics Data System (ADS)

    Grandou, T.

    2017-03-01

    The fermionic Green's functions of QCD exhibit an unexpected property of effective locality, which appears to be exact, involving no approximation. In the limit of strong coupling, and at eikonal and quenching approximations (where this property was first discovered), effective locality implies a dependence of non-perturbative fermionic Green's functions on the full algebraic content of the rank 2-SUc(3) color algebra. At variance with Perturbation Theory and a variety of non-perturbative approaches also, C3-dependences show up, where C3 stands for the second, trilinear Casimir invariant of SUc(3). These dependences are sub-leading in magnitude and seem to comply with the maximally allowed departures from the pure C2 behaviours advocated by lattice numerical estimates.

  9. Strong-field ionization of lithium

    SciTech Connect

    Schuricke, Michael; Zhu Ganjun; Steinmann, Jochen; Simeonidis, Konstantinos; Dorn, Alexander; Ullrich, Joachim; Ivanov, Igor; Kheifets, Anatoli; Grum-Grzhimailo, Alexei N.; Bartschat, Klaus

    2011-02-15

    We report photoelectron energy spectra, momentum, and angular distributions for the strong-field single ionization of lithium by 30-fs laser pulses. For peak intensities between 10{sup 11} and 10{sup 14} W/cm{sup 2} at a central wavelength of 785 nm, the classical over-the-barrier intensity was reached well inside the multiphoton regime. The complete vector momenta of the ionization fragments were recorded by a reaction microscope with a magneto-optically trapped target (MOTREMI). On the theoretical side, the time-dependent Schroedinger equation was solved by two independent methods seeking the solution directly on a radial grid. Distinct differences between the results of both calculations and also in comparison with experiment point to a high sensitivity of this reaction with respect to small details, particularly in the description of the Li{sup +} core.

  10. Ionization Potential Depression in Strongly Coupled Plasmas

    NASA Astrophysics Data System (ADS)

    Wark, Justin; Ciricosta, Orlando; Vinko, Sam; Crowley, Basil

    2013-10-01

    The focusing of the output of 4th generation femtosecond X-ray sources to ultra-high intensities has enabled the creation of hot (close to 200-eV) aluminum plasmas at exactly solid density. Tuning of the X-ray FEL energy that produces the plasma, and observation of the subsequent K- α fluorescence from the highly charged ions allows direct measurements of the K-edges, and hence ionization potential depression (IPD). The results of these experiments show far higher depressions than those predicted by the frequently-used Stewart-Pyatt model, but appear to be in contradiction with laser-plasma experimental data at similar densities, but with hotter, less strongly-coupled plasmas. We present here new calculations of the IPD, both ab initio and analytic, and discuss the relevance of the coupling parameter to the IPD. We further explore what constitutes our understanding of the physics of IPD, and how it should be modelled.

  11. Strong quantum scarring by local impurities

    PubMed Central

    Luukko, Perttu J. J.; Drury, Byron; Klales, Anna; Kaplan, Lev; Heller, Eric J.; Räsänen, Esa

    2016-01-01

    We discover and characterise strong quantum scars, or quantum eigenstates resembling classical periodic orbits, in two-dimensional quantum wells perturbed by local impurities. These scars are not explained by ordinary scar theory, which would require the existence of short, moderately unstable periodic orbits in the perturbed system. Instead, they are supported by classical resonances in the unperturbed system and the resulting quantum near-degeneracy. Even in the case of a large number of randomly scattered impurities, the scars prefer distinct orientations that extremise the overlap with the impurities. We demonstrate that these preferred orientations can be used for highly efficient transport of quantum wave packets across the perturbed potential landscape. Assisted by the scars, wave-packet recurrences are significantly stronger than in the unperturbed system. Together with the controllability of the preferred orientations, this property may be very useful for quantum transport applications. PMID:27892510

  12. Designing asymmetric multiferroics with strong magnetoelectric coupling

    NASA Astrophysics Data System (ADS)

    Lu, Xuezeng; Xiang, Hongjun; Rondinelli, James; Materials Theory; Design Group Team

    2015-03-01

    Multiferroics offer exciting opportunities for electric-field control of magnetism. Single-phase multiferroics suitable for such applications at room temperature need much more study. Here, we propose the concept of an alternative type of multiferroics, namely, the ``asymmetric multiferroic.'' In asymmetric multiferroics, two locally stable ferroelectric states are not symmetrically equivalent, leading to different magnetic properties between these two states. Furthermore, we predict from first principles that a Fe-Cr-Mo superlattice with the LiNbO3-type structure is such an asymmetric multiferroic. The strong ferrimagnetism, high ferroelectric polarization, and significant dependence of the magnetic transition temperature on polarization make this asymmetric multiferroic an ideal candidate for realizing electric-field control of magnetism at room temperature. Our study suggests that the asymmetric multiferroic may provide an alternative playground for voltage control of magnetism and find its applications in spintronics and quantum computing.

  13. Designing asymmetric multiferroics with strong magnetoelectric coupling

    NASA Astrophysics Data System (ADS)

    Lu, X. Z.; Xiang, H. J.

    2014-09-01

    Multiferroics offer exciting opportunities for electric-field control of magnetism. Single-phase multiferroics suitable for such applications at room temperature need much more study. Here, we propose the concept of an alternative type of multiferroics, namely, the "asymmetric multiferroic." In asymmetric multiferroics, two locally stable ferroelectric states are not symmetrically equivalent, leading to different magnetic properties between these two states. Furthermore, we predict from first principles that a Fe-Cr-Mo superlattice with the LiNbO3-type structure is such an asymmetric multiferroic. The strong ferrimagnetism, high ferroelectric polarization, and significant dependence of the magnetic transition temperature on polarization make this asymmetric multiferroic an ideal candidate for realizing electric-field control of magnetism at room temperature. Our study suggests that the asymmetric multiferroic may provide an alternative playground for voltage control of magnetism and find its applications in spintronics and quantum computing.

  14. Bound states in a strong magnetic field

    SciTech Connect

    Machado, C. S.; Navarra, F. S.; Noronha, J.; Oliveira, E. G.; Ferreira Filho, L. G.

    2013-03-25

    We expect a strong magnetic field to be produced in the perpendicular direction to the reaction plane, in a noncentral heavy-ion collision . The strength of the magnetic field is estimated to be eB{approx}m{sup 2}{sub {pi}}{approx} 0.02 GeV{sup 2} at the RHIC and eB{approx} 15m{sup 2}{sub {pi}}{approx} 0.3 GeV{sup 2} at the LHC. We investigate the effects of the magnetic field on B{sup 0} and D{sup 0} mesons, focusing on the changes of the energy levels and of the mass of the bound states.

  15. Towards Integrated Marmara Strong Motion Network

    NASA Astrophysics Data System (ADS)

    Durukal, E.; Erdik, M.; Safak, E.; Ansal, A.; Ozel, O.; Alcik, H.; Mert, A.; Kafadar, N.; Korkmaz, A.; Kurtulus, A.

    2009-04-01

    Istanbul has a 65% chance of having a magnitude 7 or above earthquake within the next 30 years. As part of the preparations for the future earthquake, strong motion networks have been installed in and around Istanbul. The Marmara Strong Motion Network, operated by the Department of Earthquake Engineering of Kandilli Observatory and Earthquake Research Institute, encompasses permanent systems outlined below. It is envisaged that the networks will be run by a single entity responsible for technical management and maintanence, as well as for data management, archiving and dissemination through dedicated web-based interfaces. • Istanbul Earthquake Rapid Response and Early Warning System - IERREWS (one hundred 18-bit accelerometers for rapid response; ten 24-bit accelerometers for early warning) • IGDAŞ Gas Shutoff Network (100 accelerometers to be installed in 2010 and integrated with IERREWS) • Structural Monitoring Arrays - Fatih Sultan Mehmet Suspension Bridge (1200m-long suspension bridge across the Bosphorus, five 3-component accelerometers + GPS sensors) - Hagia Sophia Array (1500-year-old historical edifice, 9 accelerometers) - Süleymaniye Mosque Array (450-year-old historical edifice,9 accelerometers) - Fatih Mosque Array (237-year-old historical edifice, 9 accelerometers) - Kanyon Building Array (high-rise office building, 5 accelerometers) - Isbank Tower Array (high-rise office building, 5 accelerometers) - ENRON Array (power generation facility, 4 acelerometers) - Mihrimah Sultan Mosque Array (450-year-old historical edifice,9 accelerometers + tiltmeters, to be installed in 2009) - Sultanahmet Mosque Array, (390-year-old historical edifice, 9 accelerometers + tiltmeters, to be installed in 2009) • Special Arrays - Atakoy Vertical Array (four 3-component accelerometers at 25, 50, 75, and 150 m depths) - Marmara Tube Tunnel (1400 m long submerged tunnel, 128 ch. accelerometric data, 24 ch. strain data, to be installed in 2010) - Air-Force Academy

  16. Observable properties of strong gravitational lenses

    NASA Astrophysics Data System (ADS)

    Tessore, Nicolas

    2017-01-01

    It is shown which properties of a strong gravitational lens can in principle be recovered from observations of multiple extended images when no assumptions are made about the deflector or sources. The mapping between individual multiple images is identified as the carrier of information about the gravitational lens and it is shown how this information can be extracted from a hypothetical observation. The derivatives of the image map contain information about convergence ratios and reduced shears over the regions of the multiple images. For two observed images, it is not possible to reconstruct the convergence ratio and shear at the same time. For three observed images, it is possible to recover the convergence ratios and reduced shears identically. For four or more observed images, the system of constraints is overdetermined, but the same quantities can theoretically be recovered.

  17. Strongly Acidic Auxin Indole-3-Methanesulfonic Acid

    PubMed Central

    Cohen, Jerry D.; Baldi, Bruce G.; Bialek, Krystyna

    1985-01-01

    A radiochemical synthesis is described for [14C]indole-3-methanesulfonic acid (IMS), a strongly acidic auxin analog. Techniques were developed for fractionation and purification of IMS using normal and reverse phase chromatography. In addition, the utility of both Fourier transform infrared spectrometry and fast atom bombardment mass spectrometry for analysis of IMS has been demonstrated. IMS was shown to be an active auxin, stimulating soybean hypocotyl elongation, bean first internode curvature, and ethylene production. IMS uptake by thin sections of soybean hypocotyl was essentially independent of solution pH and, when applied at a 100 micromolar concentration, IMS exhibited a basipetal polarity in its transport in both corn coleoptile and soybean hypocotyl sections. [14C]IMS should, therefore, be a useful compound to study fundamental processes related to the movement of auxins in plant tissues and organelles. PMID:16664007

  18. Strong spurious phase in teleseismic correlations

    NASA Astrophysics Data System (ADS)

    Li, Lei; Campillo, Michel; Boue, Pierre; Thomas, Christine; Roux, Philippe; Shapiro, Nikolai

    2016-04-01

    In the teleseismic correlations of continuous ambient noise data from Fnet array in Japan and Lapnet array in Finland, we observed a clear spurious phase with an apparent slowness of about 4.6 s/deg and an arrival time of about 430 s, far ahead of the P arrival at around 628 s. The spurious signal is rather strong from Fnet to Lapnet, arising from the correlating between the P wave from New Zealand arriving at Fnet and the PKP wave at Lapnet. The spurious phase in the opposite direction is weaker, with the source region locating in the low-latitude Atlantic Ocean near South America. Spurious phases near P and PcP waves are also present.

  19. Strong gravity and structure of topological solitons

    NASA Astrophysics Data System (ADS)

    Rybakov, Yu. P.

    The unification of Skyrme and Faddeev chiral models describing baryons and leptons respectively as topological solitons is suggested within the framework of 16-spinor field ψ = ψ1 ⊕ ψ2 nonlinear model containing two 8-semispinors ψ1 and ψ2. Using Brioschi identity for 8-spinors and special structure of the Higgs potential V implying the spontaneous symmetry breaking, it is possible to realize topological soliton-like excitations of two kinds due to the choice of S2- or S3- manifolds as phase spaces. The interactions with electromagnetic, Yang--Mills and gravitational fields are exhibited through the extention of derivatives via gauge invariance principle. Specific inclusion in the Higgs potential of the Kretschmann gravitational invariant K = RμνσλRμνσλ/48 permits one to obtain the strong gravity behavior at small distances and guarantee the correspondence with Quantum Mechanics at large distances.

  20. Strong acoustic coupling to a superconducting qubit

    NASA Astrophysics Data System (ADS)

    Gustafsson, Martin; Aref, Thomas; Frisk Kockum, Anton; Ekström, Maria; Johansson, Göran; Delsing, Per

    2014-03-01

    Micromechanical resonators can be used to store quantum information, as shown in several recent experiments. These resonators typically have the form of membranes or beams, and phonons are localized to their vibrational eigenmodes. We present a different kind of mechanical quantum device, where propagating phonons serve as carriers for quantum information. At the core of our device is a superconducting qubit, designed to couple to Surface Acoustic Waves (SAW) in the underlying substrate through the piezoelectric effect. This type of coupling can be very strong, and in our case exceeds the coupling to any external electromagnetic modes. The acoustic waves propagate freely on the surface of the substrate, and we use a remote electro-acoustic transducer to address the qubit acoustically and listen to its emission of phonons. This presentation focuses on the basic properties of our acoustic quantum system, and we include experimental data that demonstrate the quantized coupling between the qubit and the propagating acoustic waves.

  1. Strong mobility in weakly disordered systems

    SciTech Connect

    Ben-naim, Eli; Krapivsky, Pavel

    2009-01-01

    We study transport of interacting particles in weakly disordered media. Our one-dimensional system includes (i) disorder, the hopping rate governing the movement of a particle between two neighboring lattice sites is inhomogeneous, and (ii) hard core interaction, the maximum occupancy at each site is one particle. We find that over a substantial regime, the root-mean-square displacement of a particle s grows superdiffusively with time t, {sigma}{approx}({epsilon}t){sup 2/3}, where {epsilon} is the disorder strength. Without disorder the particle displacement is subdiffusive, {sigma} {approx}t{sup 1/4}, and therefore disorder strongly enhances particle mobility. We explain this effect using scaling arguments, and verify the theoretical predictions through numerical simulations. Also, the simulations show that regardless of disorder strength, disorder leads to stronger mobility over an intermediate time regime.

  2. Resonant Strong Field Nonlinear Optical Interactions

    NASA Astrophysics Data System (ADS)

    Coppeta, David Anthony

    This work considers the steady state nonlinear response of a medium subjected to electromagnetic fields which are resonant and/or strong. In this regime, pertubation expansions in the field amplitude(s) diverge and non-pertubative techniques are required. Two general cases are considered. In the first case, radiative renormalization is applied to Four Wave Mixing (FWM) in a four level system with three resonant driving fields. The absorption and generation of a weak FWM signal are considered. Several variants including coherent anti-Stokes Raman scattering are considered. The second case is a two level atom subject to excitation by an arbitrarily amplitude modulated field. The domain of solution is extended to non-equal damping rates with zero detuning from resonance. As an example, the steady state response to step function amplitude modulation is treated.

  3. Strongly Interacting Matter at High Energy Density

    SciTech Connect

    McLerran,L.

    2008-09-07

    This lecture concerns the properties of strongly interacting matter (which is described by Quantum Chromodynamics) at very high energy density. I review the properties of matter at high temperature, discussing the deconfinement phase transition. At high baryon density and low temperature, large N{sub c} arguments are developed which suggest that high baryonic density matter is a third form of matter, Quarkyonic Matter, that is distinct from confined hadronic matter and deconfined matter. I finally discuss the Color Glass Condensate which controls the high energy limit of QCD, and forms the low x part of a hadron wavefunction. The Glasma is introduced as matter formed by the Color Glass Condensate which eventually thermalizes into a Quark Gluon Plasma.

  4. Convex Modeling of Interactions with Strong Heredity

    PubMed Central

    Haris, Asad; Witten, Daniela; Simon, Noah

    2015-01-01

    We consider the task of fitting a regression model involving interactions among a potentially large set of covariates, in which we wish to enforce strong heredity. We propose FAMILY, a very general framework for this task. Our proposal is a generalization of several existing methods, such as VANISH [Radchenko and James, 2010], hierNet [Bien et al., 2013], the all-pairs lasso, and the lasso using only main effects. It can be formulated as the solution to a convex optimization problem, which we solve using an efficient alternating directions method of multipliers (ADMM) algorithm. This algorithm has guaranteed convergence to the global optimum, can be easily specialized to any convex penalty function of interest, and allows for a straightforward extension to the setting of generalized linear models. We derive an unbiased estimator of the degrees of freedom of FAMILY, and explore its performance in a simulation study and on an HIV sequence data set.

  5. Circuit electromechanics with single photon strong coupling

    SciTech Connect

    Xue, Zheng-Yuan Yang, Li-Na; Zhou, Jian

    2015-07-13

    In circuit electromechanics, the coupling strength is usually very small. Here, replacing the capacitor in circuit electromechanics by a superconducting flux qubit, we show that the coupling among the qubit and the two resonators can induce effective electromechanical coupling which can attain the strong coupling regime at the single photon level with feasible experimental parameters. We use dispersive couplings among two resonators and the qubit while the qubit is also driven by an external classical field. These couplings form a three-wave mixing configuration among the three elements where the qubit degree of freedom can be adiabatically eliminated, and thus results in the enhanced coupling between the two resonators. Therefore, our work constitutes the first step towards studying quantum nonlinear effect in circuit electromechanics.

  6. Pairing phenomena in strongly correlated Fermi liquids

    NASA Astrophysics Data System (ADS)

    Krotscheck, E.; Smith, R. A.; Jackson, A. D.

    1981-12-01

    The correlated-basis-function method is extended to deal with pairing phenomena in strongly correlated Fermi liquids. With a variational ansatz for the model wave function we derive the "correlated" analog of the conventional Bardeen-Cooper-Schrieffer (or Balian-Werthamer), Anderson-Brinkman-Morel theory of pairing. A suitable (and well-controlled) set of approximations brings the theory into a form identical to the conventional theories, but with the bare interaction replaced by a weak effective interaction and the bare single-particle energies replaced by an effective single-particle spectrum. As usual, liquid 3He provides a very stringent test of the theory, as both the interaction and the experimental facts are pretty clear. The variational estimates for the pairing interaction are improved by nonorthogonal perturbation theory. We find the expected enhancement of the attraction in P waves, although the restriction to effective two-body interactions appears to be insufficient to generate P-wave pairing.

  7. Origin of strong dispersion in Hubbard insulators

    DOE PAGES

    Wang, Y.; Wohlfeld, K.; Moritz, B.; ...

    2015-08-10

    Using cluster perturbation theory, we explain the origin of the strongly dispersive feature found at high binding energy in the spectral function of the Hubbard model. By comparing the Hubbard and $t₋J₋3s$ model spectra, we show that this dispersion does not originate from either coupling to spin fluctuations ($∝ J$ ) or the free hopping ($∝ t$ ). Instead, it should be attributed to a long-range, correlated hopping $∝ t²/U$ which allows an effectively free motion of the hole within the same antiferromagnetic sublattice. This origin explains both the formation of the high-energy anomaly in the single-particle spectrum and themore » sensitivity of the high-binding-energy dispersion to the next-nearest-neighbor hopping $t'$ .« less

  8. Origin of strong dispersion in Hubbard insulators

    SciTech Connect

    Wang, Y.; Wohlfeld, K.; Moritz, B.; Jia, C. J.; van Veenendaal, M.; Wu, K.; Chen, C. -C.; Devereaux, T. P.

    2015-08-10

    Using cluster perturbation theory, we explain the origin of the strongly dispersive feature found at high binding energy in the spectral function of the Hubbard model. By comparing the Hubbard and $t₋J₋3s$ model spectra, we show that this dispersion does not originate from either coupling to spin fluctuations ($∝ J$ ) or the free hopping ($∝ t$ ). Instead, it should be attributed to a long-range, correlated hopping $∝ t²/U$ which allows an effectively free motion of the hole within the same antiferromagnetic sublattice. This origin explains both the formation of the high-energy anomaly in the single-particle spectrum and the sensitivity of the high-binding-energy dispersion to the next-nearest-neighbor hopping $t'$ .

  9. Competition between radiative and strong force decay

    NASA Astrophysics Data System (ADS)

    Tabor, Samuel

    2017-01-01

    For nuclear states unbound to neutron decay, radiative emission is often assumed to not dominate over neutron decay mediated by the far stronger strong interaction, except for very low neutron energies and high angular momentum barriers. Recent experimental investigations of 19O and 27 Mg populated in heavy-ion fusion-evaporation reactions have revealed predominantly gamma decays from a number of states unbound to neutron decay by up to 2 MeV. In most cases the angular momentum barrier is not sufficient to inhibit neutron decay enough to allow E-M decay with widths of up to an eV or so to win. Other inhibitions to particle decay, including low spectroscopic factors, will be discussed. Supported in part by NSF Grant No. 1401574.

  10. Scaling of chaos in strongly nonlinear lattices

    SciTech Connect

    Mulansky, Mario

    2014-06-15

    Although it is now understood that chaos in complex classical systems is the foundation of thermodynamic behavior, the detailed relations between the microscopic properties of the chaotic dynamics and the macroscopic thermodynamic observations still remain mostly in the dark. In this work, we numerically analyze the probability of chaos in strongly nonlinear Hamiltonian systems and find different scaling properties depending on the nonlinear structure of the model. We argue that these different scaling laws of chaos have definite consequences for the macroscopic diffusive behavior, as chaos is the microscopic mechanism of diffusion. This is compared with previous results on chaotic diffusion [M. Mulansky and A. Pikovsky, New J. Phys. 15, 053015 (2013)], and a relation between microscopic chaos and macroscopic diffusion is established.

  11. Is It Possible to Predict Strong Earthquakes?

    NASA Astrophysics Data System (ADS)

    Polyakov, Y. S.; Ryabinin, G. V.; Solovyeva, A. B.; Timashev, S. F.

    2015-07-01

    The possibility of earthquake prediction is one of the key open questions in modern geophysics. We propose an approach based on the analysis of common short-term candidate precursors (2 weeks to 3 months prior to strong earthquake) with the subsequent processing of brain activity signals generated in specific types of rats (kept in laboratory settings) who reportedly sense an impending earthquake a few days prior to the event. We illustrate the identification of short-term precursors using the groundwater sodium-ion concentration data in the time frame from 2010 to 2014 (a major earthquake occurred on 28 February 2013) recorded at two different sites in the southeastern part of the Kamchatka Peninsula, Russia. The candidate precursors are observed as synchronized peaks in the nonstationarity factors, introduced within the flicker-noise spectroscopy framework for signal processing, for the high-frequency component of both time series. These peaks correspond to the local reorganizations of the underlying geophysical system that are believed to precede strong earthquakes. The rodent brain activity signals are selected as potential "immediate" (up to 2 weeks) deterministic precursors because of the recent scientific reports confirming that rodents sense imminent earthquakes and the population-genetic model of K irshvink (Soc Am 90, 312-323, 2000) showing how a reliable genetic seismic escape response system may have developed over the period of several hundred million years in certain animals. The use of brain activity signals, such as electroencephalograms, in contrast to conventional abnormal animal behavior observations, enables one to apply the standard "input-sensor-response" approach to determine what input signals trigger specific seismic escape brain activity responses.

  12. Strong curvature effects in Neumann wave problems

    SciTech Connect

    Willatzen, M.; Pors, A.; Gravesen, J.

    2012-08-15

    Waveguide phenomena play a major role in basic sciences and engineering. The Helmholtz equation is the governing equation for the electric field in electromagnetic wave propagation and the acoustic pressure in the study of pressure dynamics. The Schroedinger equation simplifies to the Helmholtz equation for a quantum-mechanical particle confined by infinite barriers relevant in semiconductor physics. With this in mind and the interest to tailor waveguides towards a desired spectrum and modal pattern structure in classical structures and nanostructures, it becomes increasingly important to understand the influence of curvature effects in waveguides. In this work, we demonstrate analytically strong curvature effects for the eigenvalue spectrum of the Helmholtz equation with Neumann boundary conditions in cases where the waveguide cross section is a circular sector. It is found that the linear-in-curvature contribution originates from parity symmetry breaking of eigenstates in circular-sector tori and hence vanishes in a torus with a complete circular cross section. The same strong curvature effect is not present in waveguides subject to Dirichlet boundary conditions where curvature contributions contribute to second-order in the curvature only. We demonstrate this finding by considering wave propagation in a circular-sector torus corresponding to Neumann and Dirichlet boundary conditions, respectively. Results for relative eigenfrequency shifts and modes are determined and compared with three-dimensional finite element method results. Good agreement is found between the present analytical method using a combination of differential geometry with perturbation theory and finite element results for a large range of curvature ratios.

  13. Bodrum Strong Motion Network, Mugla, Turkey

    NASA Astrophysics Data System (ADS)

    Alcik, H. A.; Tanircan, G.; Korkmaz, A.

    2015-12-01

    The Gulf of Gökova is located in southwestern Turkey near the Aegean Sea and surrounded by Datça Peninsula to the south, the island of Kos to the west and Bodrum Peninsula to the north. The Bodrum peninsula with a population of one million in summer season is one of the most populated touristic centers of Turkey. This region is also surrounded by numerous active seismic entities such as Ula-Ören Fault Zone, Gökova Graben etc.. and demonstrates high seismic hazard. In the past, many destructive earthquakes have occurred in southwestern Turkey. One of the destructive historical earthquakes is 1493 Kos event (Mw=6.9) caused heavy damage in Bodrum. In the instrumental period seismic activity in the Gökova region includes the Ms>6.0 earthquakes of 23 April 1933 (Ms=6.4), 23 May 1941 (Ms=6.0), 13 December 1941 (Ms=6.5) events. Intense earthquake activity (Mw5+) occurred in Gulf of Gökova in August 2004 and January 2005. Considering the high seismicity and population of this region, a strong ground motion monitoring system stationed in dense settlements in the Bodrum Peninsula: Bodrum, Turgutreis, Yalıkavak, Çiftlik and Ortakent was deployed on June 2015. The network consists of 5 strong motion recorders, has been set up with the aim of monitoring of regional earthquakes, collecting accurate and reliable data for engineering and scientific research purposes, in particular to provide input for future earthquake rapid reporting and early warning implementation projects on urban environments in the Bodrum peninsula and the surrounding areas. In this poster presentation, we briefly introduce the Bodrum Network and discuss our future plans for further developments.

  14. Cyclotron resonance cooling by strong laser field

    SciTech Connect

    Tagcuhi, Toshihiro; Mima, Kunioka

    1995-12-31

    Reduction of energy spread of electron beam is very important to increase a total output radiation power in free electron lasers. Although several cooling systems of particle beams such as a stochastic cooling are successfully operated in the accelerator physics, these cooling mechanisms are very slow and they are only applicable to high energy charged particle beams of ring accelerators. We propose here a new concept of laser cooling system by means of cyclotron resonance. Electrons being in cyclotron motion under a strong magnetic field can resonate with circular polarized electromagnetic field, and the resonance take place selectively depending on the velocity of the electrons. If cyclotron frequency of electrons is equal to the frequency of the electromagnetic field, they absorb the electromagnetic field energy strongly, but the other electrons remain unchanged. The absorbed energy will be converted to transverse kinetic energy, and the energy will be dumped into the radiation energy through bremastrahlung. To build a cooling system, we must use two laser beams, where one of them is counter-propagating and the other is co-propagating with electron beam. When the frequency of the counter-propagating laser is tuned with the cyclotron frequency of fast electrons and the co-propagating laser is tuned with the cyclotron frequency of slow electrons, the energy of two groups will approach and the cooling will be achieved. We solve relativistic motions of electrons with relativistic radiation dumping force, and estimate the cooling rate of this mechanism. We will report optimum parameters for the electron beam cooling system for free electron lasers.

  15. Surfactant Protein A and B Gene Polymorphisms and Risk of Respiratory Distress Syndrome in Late-Preterm Neonates

    PubMed Central

    Tsitoura, Maria-Eleni I.; Stavrou, Eleana F.; Maraziotis, Ioannis A.; Sarafidis, Kosmas; Athanassiadou, Aglaia; Dimitriou, Gabriel

    2016-01-01

    Background and Objectives Newborns delivered late-preterm (between 340/7 and 366/7 weeks of gestation) are at increased risk of respiratory distress syndrome (RDS). Polymorphisms within the surfactant protein (SP) A and B gene have been shown to predispose to RDS in preterm neonates. The aim of this study was to investigate whether specific SP-A and/or SP-B genetic variants are also associated with RDS in infants born late-preterm. Methods This prospective cross-sectional study included 56 late-preterm infants with and 60 without RDS. Specific SP-A1/SP-A2 haplotypes and SP-B Ile131Thr polymorphic alleles were determined in blood specimens using polymerase-chain-reaction and DNA sequencing. Results The SP-A1 6A4 and the SP-A2 1A5 haplotypes were significantly overrepresented in newborns with RDS compared to controls (OR 2.86, 95%CI 1.20–6.83 and OR 4.68, 95%CI 1.28–17.1, respectively). The distribution of the SP-B Ile131Thr genotypes was similar between the two late-preterm groups. Overall, the SP-A1 6A4 or/and SP-A2 1A5 haplotype was present in 20 newborns with RDS (35.7%), resulting in a 4.2-fold (1.60–11.0) higher probability of RDS in carriers. Multivariable regression analysis revealed that the effect of SP-A1 6A4 and SP-A2 1A5 haplotypes was preserved when adjusting for known risk or protective factors, such as male gender, smaller gestational age, smaller weight, complications of pregnancy, and administration of antenatal corticosteroids. Conclusions Specific SP-A genetic variants may influence the susceptibility to RDS in late-preterm infants, independently of the effect of other perinatal factors. PMID:27835691

  16. A genetic sensor for strong methylating compounds

    PubMed Central

    Moser, Felix; Horwitz, Andrew; Chen, Jacinto; Lim, Wendell A.; Voigt, Christopher A.

    2013-01-01

    Methylating chemicals are common in industry and agriculture and are often toxic, partly due to their propensity to methylate DNA. The Escherichia coli Ada protein detects methylating compounds by sensing aberrant methyl adducts on the phosphoester backbone of DNA. We characterize this system as a genetic sensor and engineer it to lower the detection threshold. By overexpressing Ada from a plasmid, we improve the sensor’s dynamic range to 350-fold induction and lower its detection threshold to 40 µM for methyl iodide. In eukaryotes, there is no known sensor of methyl adducts on the phosphoester backbone of DNA. By fusing the N-terminal domain of Ada to the Gal4 transcriptional activation domain, we built a functional sensor for methyl phosphotriester adducts in Saccharomyces cerevisiae. This sensor can be tuned to variable specifications by altering the expression level of the chimeric sensor and changing the number of Ada operators upstream of the Gal4-sensitive reporter promoter. These changes result in a detection threshold of 28 µM and 5.2-fold induction in response to methyl iodide. When the yeast sensor is exposed to different SN1 and SN2 alkylating compounds, its response profile is similar to that observed for the native Ada protein in E. coli, indicating that its native function is retained in yeast. Finally, we demonstrate that the specifications achieved for the yeast sensor are suitable for detecting methylating compounds at relevant concentrations in environmental samples. This work demonstrates the movement of a sensor from a prokaryotic to eukaryotic system and its rational tuning to achieve desired specifications. PMID:24032656

  17. Momentum transport in strongly coupled anisotropic plasmas in the presence of strong magnetic fields

    NASA Astrophysics Data System (ADS)

    Finazzo, Stefano Ivo; Critelli, Renato; Rougemont, Romulo; Noronha, Jorge

    2016-09-01

    We present a holographic perspective on momentum transport in strongly coupled, anisotropic non-Abelian plasmas in the presence of strong magnetic fields. We compute the anisotropic heavy quark drag forces and Langevin diffusion coefficients and also the anisotropic shear viscosities for two different holographic models, namely, a top-down deformation of strongly coupled N =4 super-Yang-Mills theory triggered by an external Abelian magnetic field, and a bottom-up Einstein-Maxwell-dilaton (EMD) model which is able to provide a quantitative description of lattice QCD thermodynamics with (2 +1 ) flavors at both zero and nonzero magnetic fields. We find that, in general, energy loss and momentum diffusion through strongly coupled anisotropic plasmas are enhanced by a magnetic field being larger in transverse directions than in the direction parallel to the magnetic field. Moreover, the anisotropic shear viscosity coefficient is smaller in the direction of the magnetic field than in the plane perpendicular to the field, which indicates that strongly coupled anisotropic plasmas become closer to the perfect fluid limit along the magnetic field. We also present, in the context of the EMD model, holographic predictions for the entropy density and the crossover critical temperature in a wider region of the (T , B ) phase diagram that has not yet been covered by lattice simulations. Our results for the transport coefficients in the phenomenologically realistic magnetic EMD model could be readily used as inputs in numerical codes for magnetohydrodynamics.

  18. Strong Motion Seismograph Based On MEMS Accelerometer

    NASA Astrophysics Data System (ADS)

    Teng, Y.; Hu, X.

    2013-12-01

    The MEMS strong motion seismograph we developed used the modularization method to design its software and hardware.It can fit various needs in different application situation.The hardware of the instrument is composed of a MEMS accelerometer,a control processor system,a data-storage system,a wired real-time data transmission system by IP network,a wireless data transmission module by 3G broadband,a GPS calibration module and power supply system with a large-volumn lithium battery in it. Among it,the seismograph's sensor adopted a three-axis with 14-bit high resolution and digital output MEMS accelerometer.Its noise level just reach about 99μg/√Hz and ×2g to ×8g dynamically selectable full-scale.Its output data rates from 1.56Hz to 800Hz. Its maximum current consumption is merely 165μA,and the device is so small that it is available in a 3mm×3mm×1mm QFN package. Furthermore,there is access to both low pass filtered data as well as high pass filtered data,which minimizes the data analysis required for earthquake signal detection. So,the data post-processing can be simplified. Controlling process system adopts a 32-bit low power consumption embedded ARM9 processor-S3C2440 and is based on the Linux operation system.The processor's operating clock at 400MHz.The controlling system's main memory is a 64MB SDRAM with a 256MB flash-memory.Besides,an external high-capacity SD card data memory can be easily added.So the system can meet the requirements for data acquisition,data processing,data transmission,data storage,and so on. Both wired and wireless network can satisfy remote real-time monitoring, data transmission,system maintenance,status monitoring or updating software.Linux was embedded and multi-layer designed conception was used.The code, including sensor hardware driver,the data acquisition,earthquake setting out and so on,was written on medium layer.The hardware driver consist of IIC-Bus interface driver, IO driver and asynchronous notification driver. The

  19. The quality of microparticulated protein.

    PubMed

    Erdman, J W

    1990-08-01

    The purpose of this paper is to describe the effects of microparticulation upon the quality of microparticulated protein products and to confirm that microparticulation does not result in changes in protein structure or quality different from those that occur with cooking. Two products were tested: microparticulated egg white and skim milk proteins and microparticulated whey protein concentrate. Three approaches were used to monitor for changes in amino acid and protein value: amino acid analysis, protein efficiency ratio (PER) bioassay, and both one- and two-dimensional sodium dodecyl sulfate polyacrylamide gel electrophoresis. Evaluation of the results of these tests indicates that no significant differences were found when comparing the premix before and after microparticulation. Significant differences also did not occur when the premix was cooked using conventional methods. Collectively, the data provide strong evidence that the protein microparticulation process used to prepare microparticulated protein products (e.g., Simplesse) does not alter the quality or nutritional value of protein in the final products.

  20. Electronic properties of strongly correlated layered oxides

    NASA Astrophysics Data System (ADS)

    Lee, Wei-Cheng

    The two-dimensional electronic systems (2DESs) have kept surprising physicists for the last few decades. Examples include the integer and fractional quantum Hall effects, cuprate superconductivity, and graphene. This thesis is intended to develop suitable theoretical tools which can be generalized to study new types of 2DESs with strong correlation feature. The first part of this thesis describes the investigation of heterostructures made by Mott insulators. This work is mostly motivated by the significant improvement of techniques for layer-by-layer growth of transition metal oxides in the last few years. We construct a toy model based on generalized Hubbard model complemented with long-ranged Coulomb interaction, and we study it by Hartree-Fock theory, dynamical mean-field theory, and Thomas-Fermi theory. We argue that interesting 2D strongly correlated electronic systems can be created in such heterostructures under several conditions. Since these 2D systems are formed entirely due to the gap generated by electron-electron interaction, they are not addiabatically connected to a noninteracting electron states. This feature makes these 2D systems distinguish from the ones created in semiconductor heterostructures, and they may be potential systems having non-Fermi liquid behaviors. The second part of this thesis is devoted to the study of collective excitations in high-temperature superconductors. One important achievement in this work is to develop a time-dependent mean-field theory for t -- U -- J -- V model, an effective low energy model for cuprates. The time-dependent mean-field theory is proven to be identical to the generalized random-phase approximation (GRPA) which includes both the bubble and ladder diagrams. We propose that the famous 41 meV magnetic resonance mode observed in the inelastic neutron scattering measurements is a collective mode arising from a conjugation relation, which has been overlooked in previous work, between the antiferromagnetic

  1. Developing Strong Geoscience Programs and Departments

    NASA Astrophysics Data System (ADS)

    MacDonald, R.; Manduca, C. A.

    2002-12-01

    Strong geoscience programs are essential for preparing future geoscientists and developing a broad public understanding of our science. Faculty working as a department team can create stronger programs than individual faculty working alone. Workshops sponsored by Project Kaleidoscope (www.pkal.org) on departmental planning in the geosciences have emphasized the importance of designing programs in the context of both departmental and student goals. Well-articulated goals form a foundation for designing curriculum, courses, and other departmental activities. Course/skill matrices have emerged as particularly valuable tools for analyzing how individual courses combine in a curriculum to meet learning goals. Integrated programs where students have opportunities to learn and use skills in multiple contexts have been developed at several institutions. Departments are leveraging synergies between courses to more effectively reach departmental goals and capitalize on opportunities in the larger campus environment. A full departmental program extends beyond courses and curriculum. Studies in physics (National Task Force on Undergraduate Physics, Hilborne, 2002) indicate the importance of activities such as recruiting able students, mentoring students, providing courses appropriate for pre-service K-12 teachers, assisting with professional development for a diversity of careers, providing opportunities for undergraduates to participate in research, and making connections with the local industries and businesses that employ graduates. PKAL workshop participants have articulated a wide variety of approaches to undergraduate research opportunities within and outside of class based on their departmental goals, faculty goals, and resources. Similarly, departments have a wide variety of strategies for developing productive synergies with campus-wide programs including those emphasizing writing skills, quantitative skills, and environmental studies. Mentoring and advising

  2. Strong liquid-crystalline polymeric compositions

    DOEpatents

    Dowell, F.

    1993-12-07

    Strong liquid-crystalline polymeric (LCP) compositions of matter are described. LCP backbones are combined with liquid crystalline (LC) side chains in a manner which maximizes molecular ordering through interdigitation of the side chains, thereby yielding materials which are predicted to have superior mechanical properties over existing LCPs. The theoretical design of LCPs having such characteristics includes consideration of the spacing distance between side chains along the backbone, the need for rigid sections in the backbone and in the side chains, the degree of polymerization, the length of the side chains, the regularity of the spacing of the side chains along the backbone, the interdigitation of side chains in sub-molecular strips, the packing of the side chains on one or two sides of the backbone to which they are attached, the symmetry of the side chains, the points of attachment of the side chains to the backbone, the flexibility and size of the chemical group connecting each side chain to the backbone, the effect of semiflexible sections in the backbone and the side chains, and the choice of types of dipolar and/or hydrogen bonding forces in the backbones and the side chains for easy alignment. 27 figures.

  3. Strong liquid-crystalline polymeric compositions

    DOEpatents

    Dowell, Flonnie

    1993-01-01

    Strong liquid-crystalline polymeric (LCP) compositions of matter. LCP backbones are combined with liquid crystalline (LC) side chains in a manner which maximizes molecular ordering through interdigitation of the side chains, thereby yielding materials which are predicted to have superior mechanical properties over existing LCPs. The theoretical design of LCPs having such characteristics includes consideration of the spacing distance between side chains along the backbone, the need for rigid sections in the backbone and in the side chains, the degree of polymerization, the length of the side chains, the regularity of the spacing of the side chains along the backbone, the interdigitation of side chains in sub-molecular strips, the packing of the side chains on one or two sides of the backbone to which they are attached, the symmetry of the side chains, the points of attachment of the side chains to the backbone, the flexibility and size of the chemical group connecting each side chain to the backbone, the effect of semiflexible sections in the backbone and the side chains, and the choice of types of dipolar and/or hydrogen bonding forces in the backbones and the side chains for easy alignment.

  4. Strong washout approximation to resonant leptogenesis

    NASA Astrophysics Data System (ADS)

    Garbrecht, Björn; Gautier, Florian; Klaric, Juraj

    2014-09-01

    We show that the effective decay asymmetry for resonant Leptogenesis in the strong washout regime with two sterile neutrinos and a single active flavour can in wide regions of parameter space be approximated by its late-time limit ɛ=Xsin(2varphi)/(X2+sin2varphi), where X=8πΔ/(|Y1|2+|Y2|2), Δ=4(M1-M2)/(M1+M2), varphi=arg(Y2/Y1), and M1,2, Y1,2 are the masses and Yukawa couplings of the sterile neutrinos. This approximation in particular extends to parametric regions where |Y1,2|2gg Δ, i.e. where the width dominates the mass splitting. We generalise the formula for the effective decay asymmetry to the case of several flavours of active leptons and demonstrate how this quantity can be used to calculate the lepton asymmetry for phenomenological scenarios that are in agreement with the observed neutrino oscillations. We establish analytic criteria for the validity of the late-time approximation for the decay asymmetry and compare these with numerical results that are obtained by solving for the mixing and the oscillations of the sterile neutrinos. For phenomenologically viable models with two sterile neutrinos, we find that the flavoured effective late-time decay asymmetry can be applied throughout parameter space.

  5. Observed strong currents under global tropical cyclones

    NASA Astrophysics Data System (ADS)

    Chang, Yu-Chia; Tseng, Ruo-Shan; Chu, Peter C.; Chen, Jau-Ming; Centurioni, Luca R.

    2016-07-01

    Global data from drifters of the Surface Velocity Program (Niiler, 2001) and tropical cyclones (TCs) from the Joint Typhoon Warning Center and National Hurricane Center were analyzed to demonstrate strong ocean currents and their characteristics under various storm intensities in the Northern Hemisphere (NH) and in the Southern Hemisphere (SH). Mean TC's translation speed (Uh) is faster in the NH (~ 4.7 m s- 1) than in the SH (~ 4.0 m s- 1), owing to the fact that TCs are more intense in the NH than in the SH. The rightward (leftward) bias of ocean mixed-layer (OML) velocity occurs in the NH (SH). As a result of this slower Uh and thus a smaller Froude number in the SH, the flow patterns in the SH under the same intensity levels of TCs are more symmetric relative to the TC center and the OML velocities are stronger. This study provides the first characterization of the near-surface OML velocity response to all recorded TCs in the SH from direct velocity measurements.

  6. Strong thin membrane structure. [solar sails

    NASA Technical Reports Server (NTRS)

    Frazer, R. E. (Inventor)

    1979-01-01

    A continuous process is described for producing strong lightweight structures for use as solar sails for spacecraft propulsion by radiation pressure. A thin reflective coating, such as aluminum, is applied to a rotating cylinder. A nylon mesh, applied over the aluminum coating, is then coated with a polymerizing material such as a para-xylylene monomer gas to polymerize as a film bound to the mesh and the aluminum. An emissivity increasing material such as chromium or silicon monoxide is applied to the polymer film to disperse such material colloidally into the growing polymer film, or to the final polymer film. The resulting membrane structure is then removed from the cylinder. Alternately, the membrane structure can be formed by etching a substrate in the form of an organic film such as a polymide, or a metal foil, to remove material from the substrate and reduce its thickness. A thin reflective coating (aluminum) is applied on one side of the substrate, and an emissivity increasing coating is applied on the reverse side of the substrate.

  7. Atoms and Molecules in Strong Magnetic Fields

    NASA Astrophysics Data System (ADS)

    Schmelcher, P.; Cederbaum, L. S.

    Selected topics on atoms and molecules in strong magnetic fields are reviewed. The enormous progress made for the hydrogen atom in a magnetic field and its impact on different areas like, for example, modern semi-classics and dynamics of non-integrable systems as well as laser spectroscopy are outlined. Due to the non-separability of the centre of mass and electronic motion of atoms/molecules in magnetic fields a variety of two-body phenomena can be observed in highly excited systems. Examples are the classical diffusion of the centre of mass and the giant dipole states for crossed fields. For ions energy transfer processes lead to the so-called self-ionisation process. Magnetically induced crossovers for the ground states of atoms are investigated. The increasing complexity of the ground state behaviour of magnetically dressed multi-electron atoms due to changes of the spin polarisation as well as spatial orbitals is demonstrated. For molecules, both fundamental aspects as well as the electronic structure of few-electron diatomics are reviewed.

  8. Binary Polymer Brushes of Strongly Immiscible Polymers.

    PubMed

    Chu, Elza; Babar, Tashnia; Bruist, Michael F; Sidorenko, Alexander

    2015-06-17

    The phenomenon of microphase separation is an example of self-assembly in soft matter and has been observed in block copolymers (BCPs) and similar materials (i.e., supramolecular assemblies (SMAs) and homo/block copolymer blends (HBCs)). In this study, we use microphase separation to construct responsive polymer brushes that collapse to generate periodic surfaces. This is achieved by a chemical reaction between the minor block (10%, poly(4-vinylpyridine)) of the block copolymer and a substrate. The major block of polystyrene (PS) forms mosaic-like arrays of grafted patches that are 10-20 nm in size. Depending on the nature of the assembly (SMA, HBC, or neat BCP) and annealing method (exposure to vapors of different solvents or heating above the glass transition temperature), a range of "mosaic" brushes with different parameters can be obtained. Successive grafting of a secondary polymer (polyacrylamide, PAAm) results in the fabrication of binary polymer brushes (BPBs). Upon being exposed to specific selective solvents, BPBs may adopt different conformations. The surface tension and adhesion of the binary brush are governed by the polymer occupying the top stratum. The "mosaic" brush approach allows for a combination of strongly immiscible polymers in one brush. This facilitates substantial contrast in the surface properties upon switching, previously only possible for substrates composed of predetermined nanostructures. We also demonstrate a possible application of such PS/PAAm brushes in a tunable bioadhesion-bioadhesive (PS on top) or nonbioadhesive (PAAm on top) surface as revealed by Escherichia coli bacterial seeding.

  9. Simulating strongly coupled plasmas at low temperatures

    NASA Astrophysics Data System (ADS)

    Bussmann, M.; Schramm, U.; Habs, D.

    2006-10-01

    Realistic molecular dynamics (MD) simulations of the particle dynamics in strongly coupled plasmas require the computation of the mutual Coulomb-force for each pair of charged particles if a correct treatment of long range correlations is required. For plasmas with N > 104 particles this requires a tremendous number of computational steps which can only be addressed using efficient parallel algorithms adopted to modern super-computers. We present a new versatile MD simulation code which can simulate the non-relativistic mutual Coulomb-interaction of a large number of charged particles in arbitrary external field configurations. A demanding application is the simulation of the complete dynamics of in-trap stopping of highly charged ions in a laser cooled plasma of N = 105 24Mg+ ions. We demonstrate that the simulation is capable of delivering results on stopping times and plasma dynamics under realistic conditions. The results suggest that this stopping scheme can compete with in-trap electron cooling and might be an alternative approach for delivering ultra cold highly charged ions for future trap-based experiments aiming for precision mass measurements of stable and radioactive nuclei.

  10. Emergent behavior in strongly correlated electron systems

    NASA Astrophysics Data System (ADS)

    Pines, David

    2016-09-01

    I describe early work on strongly correlated electron systems (SCES) from the perspective of a theoretical physicist who, while a participant in their reductionist top-down beginnings, is now part of the paradigm change to a bottom-up ‘emergent’ approach with its focus on using phenomenology to find the organizing principles responsible for their emergent behavior disclosed by experiment—and only then constructing microscopic models that incorporate these. After considering the organizing principles responsible for the emergence of plasmons, quasiparticles, and conventional superconductivity in SCES, I consider their application to three of SCES’s sister systems, the helium liquids, nuclei, and the nuclear matter found in neutron stars. I note some recent applications of the random phase approximation and examine briefly the role that paradigm change is playing in two central problems in our field: understanding the emergence and subsequent behavior of heavy electrons in Kondo lattice materials; and finding the mechanism for the unconventional superconductivity found in heavy electron, organic, cuprate, and iron-based materials.

  11. Emergent behavior in strongly correlated electron systems.

    PubMed

    Pines, David

    2016-09-01

    I describe early work on strongly correlated electron systems (SCES) from the perspective of a theoretical physicist who, while a participant in their reductionist top-down beginnings, is now part of the paradigm change to a bottom-up 'emergent' approach with its focus on using phenomenology to find the organizing principles responsible for their emergent behavior disclosed by experiment-and only then constructing microscopic models that incorporate these. After considering the organizing principles responsible for the emergence of plasmons, quasiparticles, and conventional superconductivity in SCES, I consider their application to three of SCES's sister systems, the helium liquids, nuclei, and the nuclear matter found in neutron stars. I note some recent applications of the random phase approximation and examine briefly the role that paradigm change is playing in two central problems in our field: understanding the emergence and subsequent behavior of heavy electrons in Kondo lattice materials; and finding the mechanism for the unconventional superconductivity found in heavy electron, organic, cuprate, and iron-based materials.

  12. Thermal infrared anomalies of several strong earthquakes.

    PubMed

    Wei, Congxin; Zhang, Yuansheng; Guo, Xiao; Hui, Shaoxing; Qin, Manzhong; Zhang, Ying

    2013-01-01

    In the history of earthquake thermal infrared research, it is undeniable that before and after strong earthquakes there are significant thermal infrared anomalies which have been interpreted as preseismic precursor in earthquake prediction and forecasting. In this paper, we studied the characteristics of thermal radiation observed before and after the 8 great earthquakes with magnitude up to Ms7.0 by using the satellite infrared remote sensing information. We used new types of data and method to extract the useful anomaly information. Based on the analyses of 8 earthquakes, we got the results as follows. (1) There are significant thermal radiation anomalies before and after earthquakes for all cases. The overall performance of anomalies includes two main stages: expanding first and narrowing later. We easily extracted and identified such seismic anomalies by method of "time-frequency relative power spectrum." (2) There exist evident and different characteristic periods and magnitudes of thermal abnormal radiation for each case. (3) Thermal radiation anomalies are closely related to the geological structure. (4) Thermal radiation has obvious characteristics in abnormal duration, range, and morphology. In summary, we should be sure that earthquake thermal infrared anomalies as useful earthquake precursor can be used in earthquake prediction and forecasting.

  13. Internal bremsstrahlung of strongly interacting charged particles

    NASA Astrophysics Data System (ADS)

    Kurgalin, S. D.; Tchuvil'sky, Yu. M.; Churakova, T. A.

    2016-11-01

    A universal theoretical model intended for calculating internal-bremsstrahlung spectra is proposed. In this model, which can be applied to describing nuclear decays of various type (such as alpha decay, cluster decay, and proton emission), use is made of realistic nucleus-nucleus potentials. Theoretical internal-bremsstrahlung spectra were obtained for the alpha decay of the 214Po nucleus, as well as for the decay of the 222Ra nucleus via the emission of a 14C cluster and for the decay of the 113Cs nucleus via proton emission, and the properties of these spectra were studied. The contributions of various regions (internal, subbarrier, and external) to the internal-bremsstrahlung amplitude were analyzed in detail. It is shown that the contribution of the internal region to the amplitude for internal bremsstrahlung generated in nuclear decay via proton emission is quite large, but that this is not so for alpha decay and decay via cluster emission. Thus, a process in which strong interaction of nuclear particles affects the internal-bremsstrahlung spectrum if found.

  14. Strong-Field THz Interactions with Wavepackets

    NASA Astrophysics Data System (ADS)

    Bucksbaum, Philip H.

    1998-03-01

    Intense THz radiation from photoconducting antennas are particularly useful for manipulating the structure and dynamics of atomic and molecular Rydberg states. We have used sub-picosecond ``half-cycle'' field pulses to follow both the radial(C. Raman, C.W.S. Conover, C.I. Sukenik, and P. H. Bucksbaum, Physical Review Letters 76), 2436 (1996). and angular motion(C.S. Raman, T.C. Weinacht, and P.H. Bucksbaum, Physical Review A 55), R3995-8 (1997). of wavepackets. The impulse imparted to an atomic electron by these pulses can also be used to produce or alter wavepacket motion. The THz radiation can be shaped by modulating optical radiation which photo-excites the antenna.(A. S. Weling et al., Appl. Phys. Lett. 64), 137, 1994. In this way we have produced intense tunable narrow-band THz radiation, which was employed to study population transfer in strongly driven Rydberg systems.(C. Raman, M. F. DeCamp and P. H. Bucksbaum, Optics Express 1) 186 (1997). The same techniques is used to arbitrarily adjust the intensity envelope of the THz pulse, alter its central frequency over a wide range, and to produce and control dispersion. When combined with active pulse-shaping and adaptive feedback techniques, wavepacket shapes and dispersion properties can be controlled.

  15. Estimating strong correlations in optical lattices

    NASA Astrophysics Data System (ADS)

    Gertis, J.; Friesdorf, M.; Riofrío, C. A.; Eisert, J.

    2016-11-01

    Ultracold atoms in optical lattices provide one of the most promising platforms for analog quantum simulations of complex quantum many-body systems. Large-size systems can now routinely be reached and are already used to probe a large variety of different physical situations, ranging from quantum phase transitions to artificial gauge theories. At the same time, measurement techniques are still limited and full tomography for these systems seems out of reach. Motivated by this observation, we present a method to directly detect and quantify to what extent a quantum state deviates from a local Gaussian description, based on available noise correlation measurements from in situ and time-of-flight measurements. This is an indicator of the significance of strong correlations in ground and thermal states, as Gaussian states are precisely the ground and thermal states of noninteracting models. We connect our findings, augmented by numerical tensor network simulations, to notions of equilibration, disordered systems, and the suppression of transport in Anderson insulators.

  16. Where are all the Strongly Shocked Meteorites?

    NASA Astrophysics Data System (ADS)

    de Carli, P. S.; Xie, Z.; Sharp, T. G.

    2008-12-01

    Recent studies of high pressure minerals in melt veins have shown that the S6 shock stage, designating the most strongly shocked chondriticmeteorites, corresponds to a peak shock pressure of about 25 GPa and an effective shock pressure duration of the order of one second. (Sharp and De Carli 2006) Calculations of the probability distribution of asteroid-asteroid impact velocities in the early solar system indicate a broad peak over the range of 2-7 km/s with a mean of 5.29 km/s. (Bottke et al 1994) The peak pressure at the point of impact between two bodies of chondritic composition would be about 25 GPa for a 2 km/s impact. For a 7 km/s impact, the peak pressure would be about 100 GPa. We would therefore expect to find a substantial population of meteorites showing evidence of having been shocked to pressures over the range between 25 and 100 GPa. In fact, there are very few chondrites that appear to have been shocked to pressures above 25 GPa. Here we present the results of Autodyn (TM) hydrocode calculations of asteroid-asteroid impacts over the velocity range of 2-7 km/s to provide a measure of the range of expected shock effects in meteorites

  17. Tolman wormholes violate the strong energy condition

    SciTech Connect

    Hochberg, D.; Molina-Paris, C.; Visser, M.

    1999-02-01

    For an arbitrary Tolman wormhole, unconstrained by symmetry, we shall define the bounce in terms of a 3-dimensional edgeless achronal spacelike hypersurface of minimal volume (zero trace for the extrinsic curvature plus a {open_quotes}flare-out{close_quotes} condition). This enables us to severely constrain the geometry of spacetime at and near the bounce and to derive general theorems regarding violations of the energy conditions{emdash}theorems that do not involve geodesic averaging but nevertheless apply to situations much more general than the highly symmetric FRW-based subclass of Tolman wormholes. [For example, even under the mildest of hypotheses, the strong energy condition (SEC) must be violated.] Alternatively, one can dispense with the minimal volume condition and define a generic bounce entirely in terms of the motion of test particles (future-pointing timelike geodesics), by looking at the expansion of their timelike geodesic congruences. One re-confirms that the SEC must be violated at or near the bounce. In contrast, it is easy to arrange for {ital all} the other standard energy conditions to be satisfied. {copyright} {ital 1999} {ital The American Physical Society}

  18. Nanoscale electrodynamics of strongly correlated quantum materials.

    PubMed

    Liu, Mengkun; Sternbach, Aaron J; Basov, D N

    2017-01-01

    Electronic, magnetic, and structural phase inhomogeneities are ubiquitous in strongly correlated quantum materials. The characteristic length scales of the phase inhomogeneities can range from atomic to mesoscopic, depending on their microscopic origins as well as various sample dependent factors. Therefore, progress with the understanding of correlated phenomena critically depends on the experimental techniques suitable to provide appropriate spatial resolution. This requirement is difficult to meet for some of the most informative methods in condensed matter physics, including infrared and optical spectroscopy. Yet, recent developments in near-field optics and imaging enabled a detailed characterization of the electromagnetic response with a spatial resolution down to 10 nm. Thus it is now feasible to exploit at the nanoscale well-established capabilities of optical methods for characterization of electronic processes and lattice dynamics in diverse classes of correlated quantum systems. This review offers a concise description of the state-of-the-art near-field techniques applied to prototypical correlated quantum materials. We also discuss complementary microscopic and spectroscopic methods which reveal important mesoscopic dynamics of quantum materials at different energy scales.

  19. Nanoscale electrodynamics of strongly correlated quantum materials

    NASA Astrophysics Data System (ADS)

    Liu, Mengkun; Sternbach, Aaron J.; Basov, D. N.

    2017-01-01

    Electronic, magnetic, and structural phase inhomogeneities are ubiquitous in strongly correlated quantum materials. The characteristic length scales of the phase inhomogeneities can range from atomic to mesoscopic, depending on their microscopic origins as well as various sample dependent factors. Therefore, progress with the understanding of correlated phenomena critically depends on the experimental techniques suitable to provide appropriate spatial resolution. This requirement is difficult to meet for some of the most informative methods in condensed matter physics, including infrared and optical spectroscopy. Yet, recent developments in near-field optics and imaging enabled a detailed characterization of the electromagnetic response with a spatial resolution down to 10 nm. Thus it is now feasible to exploit at the nanoscale well-established capabilities of optical methods for characterization of electronic processes and lattice dynamics in diverse classes of correlated quantum systems. This review offers a concise description of the state-of-the-art near-field techniques applied to prototypical correlated quantum materials. We also discuss complementary microscopic and spectroscopic methods which reveal important mesoscopic dynamics of quantum materials at different energy scales.

  20. Strong reinforcing selection in a Texas wildflower.

    PubMed

    Hopkins, Robin; Guerrero, Rafael F; Rausher, Mark D; Kirkpatrick, Mark

    2014-09-08

    Reinforcement, the process of increased reproductive isolation due to selection against hybrids, is an important mechanism by which natural selection contributes to speciation [1]. Empirical studies suggest that reinforcement has generated reproductive isolation in many taxa (reviewed in [2-4]), and theoretical work shows it can act under broad selective conditions [5-11]. However, the strength of selection driving reinforcement has never been measured in nature. Here, we quantify the strength of reinforcing selection in the Texas wildflower Phlox drummondii using a strategy that weds a population genetic model with field data. Reinforcement in this system is caused by variation in two loci that affect flower color [12]. We quantify sharp clines in flower color where this species comes into contact with its congener, Phlox cuspidata. We develop a spatially explicit population genetic model for these clines based on the known genetics of flower color. We fit our model to the data using likelihood, and we searched parameter space using Markov chain Monte Carlo methods. We find that selection on flower color genes generated by reinforcement is exceptionally strong. Our findings demonstrate that natural selection can play a decisive role in the evolution of reproductive isolation through the process of reinforcement.

  1. Grassy Silica Nanoribbons and Strong Blue Luminescence

    NASA Astrophysics Data System (ADS)

    Wang, Shengping; Xie, Shuang; Huang, Guowei; Guo, Hongxuan; Cho, Yujin; Chen, Jun; Fujita, Daisuke; Xu, Mingsheng

    2016-09-01

    Silicon dioxide (SiO2) is one of the key materials in many modern technological applications such as in metal oxide semiconductor transistors, photovoltaic solar cells, pollution removal, and biomedicine. We report the accidental discovery of free-standing grassy silica nanoribbons directly grown on SiO2/Si platform which is commonly used for field-effect transistors fabrication without other precursor. We investigate the formation mechanism of this novel silica nanostructure that has not been previously documented. The silica nanoribbons are flexible and can be manipulated by electron-beam. The silica nanoribbons exhibit strong blue emission at about 467 nm, together with UV and red emissions as investigated by cathodoluminescence technique. The origins of the luminescence are attributed to various defects in the silica nanoribbons; and the intensity change of the blue emission and green emission at about 550 nm is discussed in the frame of the defect density. Our study may lead to rational design of the new silica-based materials for a wide range of applications.

  2. DYNAMICS OF STRONGLY TWISTED RELATIVISTIC MAGNETOSPHERES

    SciTech Connect

    Parfrey, Kyle; Beloborodov, Andrei M.; Hui, Lam

    2013-09-10

    Magnetar magnetospheres are believed to be strongly twisted due to shearing of the stellar crust by internal magnetic stresses. We present time-dependent axisymmetric simulations showing in detail the evolution of relativistic force-free magnetospheres subjected to slow twisting through large angles. When the twist amplitude is small, the magnetosphere moves quasi-statically through a sequence of equilibria of increasing free energy. At some twist amplitude the magnetosphere becomes tearing-mode unstable to forming a resistive current sheet, initiating large-scale magnetic reconnection in which a significant fraction of the magnetic free energy can be dissipated. This ''critical'' twist angle is insensitive to the resistive length scale. Rapid shearing temporarily stabilizes the magnetosphere beyond the critical angle, allowing the magnetosphere of a rapidly differentially rotating star to store and dissipate more free energy. In addition to these effects, shearing the surface of a rotating star increases the spindown torque applied to the star. If shearing is much slower than rotation, the resulting spikes in spindown rate can occur on timescales anywhere from the long twisting timescale to the stellar spin period or shorter, depending both on the stellar shear distribution and the existing distribution of magnetospheric twists. A model in which energy is stored in the magnetosphere and released by a magnetospheric instability therefore predicts large changes in the measured spindown rate before soft gamma repeater giant flares.

  3. Bioinspired Strong and Highly Porous Glass Scaffolds.

    PubMed

    Fu, Qiang; Saiz, Eduardo; Tomsia, Antoni P

    2011-03-22

    The quest for more efficient energy-related technologies is driving the development of porous and high-performance structural materials with exceptional mechanical strength. Natural materials achieve their strength through complex hierarchical designs and anisotropic structures that are extremely difficult to replicate synthetically. We emulate nature's design by direct-ink-write assembling of glass scaffolds with a periodic pattern, and controlled sintering of the filaments into anisotropic constructs similar to biological materials. The final product is a porous glass scaffold with a compressive strength (136 MPa) comparable to that of cortical bone and a porosity (60%) comparable to that of trabecular bone. The strength of this porous glass scaffold is ~100 times that of polymer scaffolds and 4-5 times that of ceramic and glass scaffolds with comparable porosities reported elsewhere. The ability to create both porous and strong structures opens a new avenue for fabricating scaffolds for a broad array of applications, including tissue engineering, filtration, lightweight composites, and catalyst support.

  4. Grassy Silica Nanoribbons and Strong Blue Luminescence

    PubMed Central

    Wang, Shengping; Xie, Shuang; Huang, Guowei; Guo, Hongxuan; Cho, Yujin; Chen, Jun; Fujita, Daisuke; Xu, Mingsheng

    2016-01-01

    Silicon dioxide (SiO2) is one of the key materials in many modern technological applications such as in metal oxide semiconductor transistors, photovoltaic solar cells, pollution removal, and biomedicine. We report the accidental discovery of free-standing grassy silica nanoribbons directly grown on SiO2/Si platform which is commonly used for field-effect transistors fabrication without other precursor. We investigate the formation mechanism of this novel silica nanostructure that has not been previously documented. The silica nanoribbons are flexible and can be manipulated by electron-beam. The silica nanoribbons exhibit strong blue emission at about 467 nm, together with UV and red emissions as investigated by cathodoluminescence technique. The origins of the luminescence are attributed to various defects in the silica nanoribbons; and the intensity change of the blue emission and green emission at about 550 nm is discussed in the frame of the defect density. Our study may lead to rational design of the new silica-based materials for a wide range of applications. PMID:27666663

  5. Strongly magnetized rotating dipole in general relativity

    NASA Astrophysics Data System (ADS)

    Pétri, J.

    2016-10-01

    Context. Electromagnetic waves arise in many areas of physics. Solutions are difficult to find in the general case. Aims: We numerically integrate Maxwell equations in a 3D spherical polar coordinate system. Methods: Straightforward finite difference methods would lead to a coordinate singularity along the polar axis. Spectral methods are better suited for such artificial singularities that are related to the choice of a coordinate system. When the radiating object rotates like a star, for example, special classes of solutions to Maxwell equations are worthwhile to study, such as quasi-stationary regimes. Moreover, in high-energy astrophysics, strong gravitational and magnetic fields are present especially around rotating neutron stars. Results: To study such systems, we designed an algorithm to solve the time-dependent Maxwell equations in spherical polar coordinates including general relativity and quantum electrodynamical corrections to leading order. As a diagnostic, we computed the spin-down luminosity expected for these stars and compared it to the classical or non-relativistic and non-quantum mechanical results. Conclusions: Quantum electrodynamics leads to an irrelevant change in the spin-down luminosity even for a magnetic field of about the critical value of 4.4 × 109 T. Therefore the braking index remains close to its value for a point dipole in vacuum, namely n = 3. The same conclusion holds for a general-relativistic quantum electrodynamically corrected force-free magnetosphere.

  6. PARTICLE ACCELERATION IN SUPERLUMINAL STRONG WAVES

    SciTech Connect

    Teraki, Yuto; Ito, Hirotaka; Nagataki, Shigehiro

    2015-06-01

    We calculate the electron acceleration in random superluminal strong waves (SLSWs) and radiation from them using numerical methods in the context of the termination shocks of pulsar wind nebulae. We pursue the orbit of electrons by solving the equation of motion in the analytically expressed electromagnetic turbulences. These consist of a primary SLS and isotropically distributed secondary electromagnetic waves. Under the dominance of the secondary waves, all electrons gain nearly equal energy. On the other hand, when the primary wave is dominant, selective acceleration occurs. The phase of the primary wave for electrons moving nearly along the wavevector changes very slowly compared with the oscillation of the wave, which is “phase-locked,” and such electrons are continuously accelerated. This acceleration by SLSWs may play a crucial role in pre-shock acceleration. In general, the radiation from the phase-locked population is different from the synchro-Compton radiation. However, when the amplitude of the secondary waves is not extremely weaker than that of the primary wave, the typical frequency can be estimated from synchro-Compton theory using the secondary waves. The primary wave does not contribute to the radiation because the SLSW accelerates electrons almost linearly. This radiation can be observed as a radio knot at the upstream of the termination shocks of the pulsar wind nebulae without counterparts in higher frequency ranges.

  7. Protein Condensation

    NASA Astrophysics Data System (ADS)

    Gunton, James D.; Shiryayev, Andrey; Pagan, Daniel L.

    2007-09-01

    Preface; 1. Introduction; 2. Globular protein structure; 3. Experimental methods; 4. Thermodynamics and statistical mechanics; 5. Protein-protein interactions; 6. Theoretical studies of equilibrium; 7. Nucleation theory; 8. Experimental studies of nucleation; 9. Lysozyme; 10. Some other globular proteins; 11. Membrane proteins; 12. Crystallins and cataracts; 13. Sickle hemoglobin and sickle cell anemia; 14, Alzheimer's disease; Index.

  8. Protein Condensation

    NASA Astrophysics Data System (ADS)

    Gunton, James D.; Shiryayev, Andrey; Pagan, Daniel L.

    2014-07-01

    Preface; 1. Introduction; 2. Globular protein structure; 3. Experimental methods; 4. Thermodynamics and statistical mechanics; 5. Protein-protein interactions; 6. Theoretical studies of equilibrium; 7. Nucleation theory; 8. Experimental studies of nucleation; 9. Lysozyme; 10. Some other globular proteins; 11. Membrane proteins; 12. Crystallins and cataracts; 13. Sickle hemoglobin and sickle cell anemia; 14, Alzheimer's disease; Index.

  9. PIC: Protein Interactions Calculator

    PubMed Central

    Tina, K. G.; Bhadra, R.; Srinivasan, N.

    2007-01-01

    Interactions within a protein structure and interactions between proteins in an assembly are essential considerations in understanding molecular basis of stability and functions of proteins and their complexes. There are several weak and strong interactions that render stability to a protein structure or an assembly. Protein Interactions Calculator (PIC) is a server which, given the coordinate set of 3D structure of a protein or an assembly, computes various interactions such as disulphide bonds, interactions between hydrophobic residues, ionic interactions, hydrogen bonds, aromatic–aromatic interactions, aromatic–sulphur interactions and cation–π interactions within a protein or between proteins in a complex. Interactions are calculated on the basis of standard, published criteria. The identified interactions between residues can be visualized using a RasMol and Jmol interface. The advantage with PIC server is the easy availability of inter-residue interaction calculations in a single site. It also determines the accessible surface area and residue-depth, which is the distance of a residue from the surface of the protein. User can also recognize specific kind of interactions, such as apolar–apolar residue interactions or ionic interactions, that are formed between buried or exposed residues or near the surface or deep inside. PMID:17584791

  10. PIC: Protein Interactions Calculator.

    PubMed

    Tina, K G; Bhadra, R; Srinivasan, N

    2007-07-01

    Interactions within a protein structure and interactions between proteins in an assembly are essential considerations in understanding molecular basis of stability and functions of proteins and their complexes. There are several weak and strong interactions that render stability to a protein structure or an assembly. Protein Interactions Calculator (PIC) is a server which, given the coordinate set of 3D structure of a protein or an assembly, computes various interactions such as disulphide bonds, interactions between hydrophobic residues, ionic interactions, hydrogen bonds, aromatic-aromatic interactions, aromatic-sulphur interactions and cation-pi interactions within a protein or between proteins in a complex. Interactions are calculated on the basis of standard, published criteria. The identified interactions between residues can be visualized using a RasMol and Jmol interface. The advantage with PIC server is the easy availability of inter-residue interaction calculations in a single site. It also determines the accessible surface area and residue-depth, which is the distance of a residue from the surface of the protein. User can also recognize specific kind of interactions, such as apolar-apolar residue interactions or ionic interactions, that are formed between buried or exposed residues or near the surface or deep inside.

  11. Simple rheology of mixed proteins

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Mixing different proteins to form strong gel networks for food applications may create synergistic increases in viscoelasticity that cannot be achieved with a single protein. In this study, small amplitude oscillatory shear analyses were used to investigate the rheology of calcium caseinate (CC), e...

  12. Strong washout approximation to resonant leptogenesis

    SciTech Connect

    Garbrecht, Björn; Gautier, Florian; Klaric, Juraj E-mail: florian.gautier@tum.de

    2014-09-01

    We show that the effective decay asymmetry for resonant Leptogenesis in the strong washout regime with two sterile neutrinos and a single active flavour can in wide regions of parameter space be approximated by its late-time limit ε=Xsin(2φ)/(X{sup 2}+sin{sup 2}φ), where X=8πΔ/(|Y{sub 1}|{sup 2}+|Y{sub 2}|{sup 2}), Δ=4(M{sub 1}-M{sub 2})/(M{sub 1}+M{sub 2}), φ=arg(Y{sub 2}/Y{sub 1}), and M{sub 1,2}, Y{sub 1,2} are the masses and Yukawa couplings of the sterile neutrinos. This approximation in particular extends to parametric regions where |Y{sub 1,2}|{sup 2}>> Δ, i.e. where the width dominates the mass splitting. We generalise the formula for the effective decay asymmetry to the case of several flavours of active leptons and demonstrate how this quantity can be used to calculate the lepton asymmetry for phenomenological scenarios that are in agreement with the observed neutrino oscillations. We establish analytic criteria for the validity of the late-time approximation for the decay asymmetry and compare these with numerical results that are obtained by solving for the mixing and the oscillations of the sterile neutrinos. For phenomenologically viable models with two sterile neutrinos, we find that the flavoured effective late-time decay asymmetry can be applied throughout parameter space.

  13. Strongly correlated states in ultracold atoms

    NASA Astrophysics Data System (ADS)

    Dalla Torre, Emanuele G.

    This thesis deals with novel phases and dynamical effects in strongly correlated quantum systems and is divided in two main parts. The first part deals with the effects of extended interactions on lattice bosons in one dimension. Using the density matrix renormalization group (DMRG) we showed that ultracold atoms or molecules with extended interactions, in a one dimensional optical lattice can form a novel quantum phase characterized by non-local string correlations and no broken symmetry[1]. We termed this phase a Haldane insulator due to an analogy with Haldane gapped Heisenberg spin chains. We derived a field theory description of the phase and the phase transitions from it to the conventional states, a Mott insulator and a density wave. One important outcome from this study was the observation that the topological distinction between the Haldane and Mott insulator is protected by the lattice inversion symmetry[2]. In addition, the field theoretical description allowed us to describe universal features in the dynamic response of the system to time-dependent probes[3]. In the second part, we study the effects of time-dependent noise on quantum phase transitions. We consider one particular type of noise, 1/f noise, omnipresent in low-frequency electric devices. This type of noise is scale invariant, and leads to the formation of novel non-equilibrium quantum critical states[?]. We study the effects of small static perturbations around the critical states, through a real-time renormalization group (RG) approach[4]. At the first order of our expansion (valid for short times), we find that these perturbations can lead to a sharp non-equilibrium quantum phase transition, controlled by the non-equilibrium quantum critical state. However, at the second order (valid for longer times), we actually find that the system develops a finite effective temperature, which destroys the scale invariance and turns the phase transition into a smooth crossover. Using the RG approach

  14. Physics of protein motility and motor proteins

    NASA Astrophysics Data System (ADS)

    Kolomeisky, Anatoly B.

    2013-09-01

    Motor proteins are enzymatic molecules that transform chemical energy into mechanical motion and work. They are critically important for supporting various cellular activities and functions. In the last 15 years significant progress in understanding the functioning of motor proteins has been achieved due to revolutionary breakthroughs in single-molecule experimental techniques and strong advances in theoretical modelling. However, microscopic mechanisms of protein motility are still not well explained, and the collective efforts of many scientists are needed in order to solve these complex problems. In this special section the reader will find the latest advances on the difficult road to mapping motor proteins dynamics in various systems. Recent experimental developments have allowed researchers to monitor and to influence the activity of single motor proteins with a high spatial and temporal resolution. It has stimulated significant theoretical efforts to understand the non-equilibrium nature of protein motility phenomena. The latest results from all these advances are presented and discussed in this special section. We would like to thank the scientists from all over the world who have reported their latest research results for this special section. We are also grateful to the staff and editors of Journal of Physics: Condensed Matter for their invaluable help in handling all the administrative and refereeing activities. The field of motor proteins and protein motility is fast moving, and we hope that this collection of articles will be a useful source of information in this highly interdisciplinary area. Physics of protein motility and motor proteins contents Physics of protein motility and motor proteinsAnatoly B Kolomeisky Identification of unique interactions between the flexible linker and the RecA-like domains of DEAD-box helicase Mss116 Yuan Zhang, Mirkó Palla, Andrew Sun and Jung-Chi Liao The load dependence of the physical properties of a molecular motor

  15. Strong Coupling Gauge Theories in LHC ERA

    NASA Astrophysics Data System (ADS)

    Fukaya, H.; Harada, M.; Tanabashi, M.; Yamawaki, K.

    2011-01-01

    Higgs, or techni-dilaton - composite Higgs near conformality / Koichi Yamawaki -- Phase diagram of strongly interacting theories / Francesco Sannino -- Resizing conformal windows / O. Antipin and K. Tuominen -- Nearly conformal gauge theories on the lattice / Zoltan Fodor ... [et al.] -- Going beyond QCD in lattice gauge theory / G. T. Fleming -- Phases of QCD from small to large N[symbol]: (some) lattice results / A. Deuzeman, E. Pallante and M. P. Lombardo -- Lattice gauge theory and (quasi)-conformal technicolor / D. K. Sinclair and J. B. Kogut -- Study of the running coupling constant in 10-flavor QCD with the Schrodinger functional method / N. Yamada ... [et al.] -- Study of the running coupling in twisted Polyakov scheme / T. Aoyama ... [et al.].Running coupling in strong gauge theories via the lattice / Zoltan Fodor ... [et al.] -- Higgsinoless supersymmetry and hidden gravity / Michael L. Graesser, Ryuichiro Kitano and Masafumi Kurachi -- The latest status of LHC and the EWSB physics / S. Asai -- Continuum superpartners from supersymmetric unparticles / Hsin-Chia Cheng -- Review of minimal flavor constraints for technicolor / Hidenori S. Fukano and Francesco Sannino -- Standard model and high energy Lorentz violation / Damiano Anselmi -- Dynamical electroweak symmetry breaking and fourth family / Michio Hashimoto -- Holmorphic supersymmetric Nambu-Jona-Lasino model and dynamical electroweak symmetry breaking / Dong-Won Jung, Otto C. W. Kong and Jae Sik Lee -- Ratchet model of Baryogenesis / Tatsu Takeuchi, Azusa Minamizaki and Akio Sugamoto -- Classical solutions of field equations in Einstein Gauss-Bonnet gravity / P. Suranyi, C. Vaz and L. C. R. Wijewardhana -- Black holes constitute all dark matter / Paul H. Frampton -- Electroweak precision test and Z [symbol] in the three site Higgsless model / Tomohiro Abe -- Chiral symmetry and BRST symmetry breaking, quaternion reality and the lattice simulation / Sadataka Furui -- Holographic techni-dilaton, or

  16. Ultrafiltration of pegylated proteins

    NASA Astrophysics Data System (ADS)

    Molek, Jessica R.

    groups in the PEGylated proteins. Ultrafiltration experiments were performed using PEGylated alpha-lactalbumin, ovalbumin, and bovine serum albumin. In contrast to the size exclusion chromatography data, the sieving coefficient of the PEGylated proteins depended upon both the number and size of the attached PEG chains due to the elongation or deformation of the PEG associated with the filtrate flux. Sieving coefficients at low filtrate flux were in good agreement with predictions of available hydrodynamic models, with significant elongation occurring when the Deborah number for the PEG chain exceeded 0.001. The effects of electrostatic interactions on the ultrafiltration of PEGylated proteins were examined using electrically-charged membranes generated by covalent attachment of sulphonic acid groups to the base cellulosic membrane. Transmission of PEGylated proteins through charged membranes was dramatically reduced at low ionic strength due to strong electrostatic interactions, despite the presence of the neutral PEG. The experimental results were in good agreement with model calculations developed for the partitioning of charged spheres into charged cylindrical pores. The experimental and theoretical results provide the first quantitative analysis of the effects of PEGylation on transport through semipermeable ultrafiltration membranes. The results from small-scale ultrafiltration experiments were used to develop a two-stage diafiltration process to purify PEGylated alpha-lactalbumin. The first-stage used a neutral membrane to remove the unreacted protein by exploiting differences in size. The second stage used a negatively-charged membrane to remove hydrolyzed PEG, with the PEGylated product retained by strong electrostatic interactions. This process provided a purification factor greater than 1000 with respect to the unreacted protein and greater than 20-fold with respect to the PEG with an overall yield of PEGylated alpha-lactalbumin of 78%. These results provide

  17. Implication of Terminal Residues at Protein-Protein and Protein-DNA Interfaces.

    PubMed

    Martin, Olivier M F; Etheve, Loïc; Launay, Guillaume; Martin, Juliette

    2016-01-01

    Terminal residues of protein chains are charged and more flexible than other residues since they are constrained only on one side. Do they play a particular role in protein-protein and protein-DNA interfaces? To answer this question, we considered large sets of non-redundant protein-protein and protein-DNA complexes and analyzed the status of terminal residues and their involvement in interfaces. In protein-protein complexes, we found that more than half of terminal residues (62%) are either modified by attachment of a tag peptide (10%) or have missing coordinates in the analyzed structures (52%). Terminal residues are almost exclusively located at the surface of proteins (94%). Contrary to charged residues, they are not over or under-represented in protein-protein interfaces, but strongly prefer the peripheral region of interfaces when present at the interface (83% of terminal residues). The almost exclusive location of terminal residues at the surface of the proteins or in the rim regions of interfaces explains that experimental methods relying on tail hybridization can be successfully applied without disrupting the complexes under study. Concerning conformational rearrangement in protein-protein complexes, despite their expected flexibility, terminal residues adopt similar locations between the free and bound forms of the docking benchmark. In protein-DNA complexes, N-terminal residues are twice more frequent than C-terminal residues at interfaces. Both N-terminal and C-terminal residues are under-represented in interfaces, in contrast to positively charged residues, which are strongly favored. When located in protein-DNA interfaces, terminal residues prefer the periphery. N-terminal and C-terminal residues thus have particular properties with regard to interfaces, which cannot be reduced to their charged nature.

  18. Effective Theories Of The Strong Interaction

    SciTech Connect

    Dr. Ubirajara van Kolck

    2004-07-31

    This is the final report corresponding to the full funding period (08/01-07/04) in the Department of Energy Outstanding Junior Investigator Grant DE-FG03-01ER41196. The development of an understanding of the interplay between perturbative and non-perturbative effects in strong-interacting systems forms the broad context of this research. The main thrust is the application of effective theories to QCD. Topics included a new power counting in the pionful effective theory, low-energy Compton scattering, charge-symmetry breaking in pion production and in the two-nucleon potential, parity violation, coupled-channel scattering, shallow resonances and halo nuclei, chiral symmetry in the baryon spectrum, existence of a tetraquark state, and molecular meson states. DOE grant DE-FG03-01ER41196 was used to partially support in the period 08/01-07/04 the research activities of the Principal Investigator, Dr. Ubirajara van Kolck, one post-doctoral research associate, Dr. Boris A. Gelman, and one graduate student, Mr. Will Hockings. During the grant period the PI was first Assistant then Associate Professor of Physics at the University of Arizona (UA), and a RHIC Physics Fellow at the RIKEN-BNL Research Center (RBRC). The association with RBRC ended in the Summer of 2004. Since September of 2002 the PI has also been partially supported by a Sloan Research Fellowship. Dr. Boris Gelman was supported by the grant from September 2002 to May 2004. He joined the UA after receiving a Ph.D. from the University of Maryland in the Summer of 2002. He left to take a research associate position in the nuclear theory group of the State University of New York at Stony Brook. The support of a post-doctoral researcher on this grant for two years was only possible by carrying over first- and second-year funds to later years. In addition, Mr. William Hockings started doing research under the PI's guidance. Mr. Hockings took Independent Study courses with the PI, while working as a teaching

  19. The Commercial TREMOR Strong-Motion Seismograph

    NASA Astrophysics Data System (ADS)

    Evans, J. R.; Hamstra, R. H.; Kuendig, C.; Camina, P.

    2001-12-01

    The emergence of major seismological and earthquake-engineering problems requiring large, dense instrument arrays led several of us to investigate alternate solutions. Evans and Rogers (USGS Open File Report 95-555, 1995) and Evans (USGS Open File Report 98-109, 1998) demonstrated the efficacy of low-cost robust silicon accelerometers in strong-motion seismology, making possible a vast increase in the spatial density of such arrays. The 1998 design displays true 16-bit performance and excellent robustness and linearity---13 of these prototype near-real-time instruments are deployed in Oakland, California, and have recorded data from seven small events (up to 5.7 %g). Since this technology is a radical departure from past efforts, it was necessary for the USGS to develop the sensor and demonstrate its efficacy thoroughly. Since it is neither practical nor appropriate for the USGS to produce instrumentation beyond a demonstration phase, the US Geological Survey and GeoSIG Ltd undertook a collaborative effort (a ``CRAD'') to commercialize the new technology. This effort has resulted in a fully temperature-compensated 16-bit system, the GeoSIG GT-316, announced in April, 2001, combining the ICS-3028 TM-based USGS sensor, temperature compensation technique, and peak ground velocity (PGV) computation with a highly customized 16-bit GeoSIG recorder. The price has not been set but is likely to be around \\2000 in large quantities. The result is a near-real-time instrument telemetering peak ground acceleration (PGA) and PGV about 90 s after onset of the P wave, then minutes later transmitting the waveform. The receiving software, ``HomeBase()'', also computes spectral acceleration, S_{a}. PGA, PGV, S_{a}, and waveforms are forwarded immediately by HomeBase() for ShakeMap generation and other uses. Shaking metrics from the prototypes in Oakland are consistently among the first to arrive for the northern California ShakeMap. For telemetry we use a low-cost always

  20. OBSERVATION OF STRONG - STRONG AND OTHER BEAM - BEAM EFFECTS IN RHIC.

    SciTech Connect

    Fischer, W; Brennan, J M; Cameron, P; Connolly, R; Montag, C; Peggs, S; Pilat, F; Ptitsyn, V; Tepikian, S; Trbojevic, D; Van Zeijts, J

    2003-05-12

    RHIC is currently the only hadron collider in which strong-strong beam-beam effects can be seen. For the first time, coherent beam-beam modes were observed in a bunched beam hadron collider. Other beam-beam effects in RHIC were observed in operation and in dedicated experiments with gold ions, deuterons and protons. Observations include measurements of beam-beam induced tune shifts, lifetime and emittance growth measurements with and without beam-beam interaction, and background rates as a function of tunes. During ramps unequal radio frequencies in the two rings cause the crossing points to move longitudinally. Thus bunches experience beam-beam interactions only in intervals and the tunes are modulated. In this article we summarize the most important beam-beam observations made so far.

  1. Strong electron correlations in biomimetic transition metal molecules

    NASA Astrophysics Data System (ADS)

    Labute, Montiago Xavier

    The first-row transition metals (Fe, Co, V,...) are key players in the active sites of proteins and enzymes responsible for diverse biological processes such as NO regulation and photosynthesis. Many small transition metal complexes possess chemical coordination environments in the vicinity of the metal atom that are reminiscent of these active sites. We have studied the electronic structure of these molecules and discussed the relevance for their biological analogues. The specific question on which we wish to focus is: Do strong correlations (resulting from the localized character of the TM 3d-orbitals) contribute significantly to the reaction energetics of these molecules and, if so, can these effects be observed by experiment? To accomplish these ends we focus on the cobalt valence tautomer molecules and the phenomenon of electron transfer in aqueous hexaammine cobalt ions. We utilize theoretical methods in order to study the cobalt valence tautomer molecules which undergo an interconversion with temperature that is reminiscent of the changes in structure and spin that the heme group experiences as the result of Fe-ligand interactions. We perform fully ab initio calculations using the GGA implementation of density functional theory with the computer code SIESTA. In addition, a simple Anderson Impurity Model has been employed that more properly accounts for the Coulomb interaction among the 3d electrons on the cobalt atom. The calculated Co K x-ray absorption near-edge spectra XANES agrees well with experimental data and a prediction for the Co L-edge XAS that could be tested in future experiments is also presented. We believe that there are structures in both spectra that may only be explained by a strong admixture of configurations. It is conjectured that strong electron correlations help explain the non-Arrhenius rate behavior observed in the high-spin to low-spin relaxation rate at low temperatures. Work on electron-transfer in CoNH32 +/3+6aq using these

  2. Strongly Lacunary Ward Continuity in 2-Normed Spaces

    PubMed Central

    Çakalli, Hüseyin; Ersan, Sibel

    2014-01-01

    A function f defined on a subset E of a 2-normed space X is strongly lacunary ward continuous if it preserves strongly lacunary quasi-Cauchy sequences of points in E; that is, (f(xk)) is a strongly lacunary quasi-Cauchy sequence whenever (xk) is strongly lacunary quasi-Cauchy. In this paper, not only strongly lacunary ward continuity, but also some other kinds of continuities are investigated in 2-normed spaces. PMID:25050397

  3. Strong Coupling of Localized Surface Plasmons to Excitons in Light-Harvesting Complexes

    PubMed Central

    2016-01-01

    Gold nanostructure arrays exhibit surface plasmon resonances that split after attaching light harvesting complexes 1 and 2 (LH1 and LH2) from purple bacteria. The splitting is attributed to strong coupling between the localized surface plasmon resonances and excitons in the light-harvesting complexes. Wild-type and mutant LH1 and LH2 from Rhodobacter sphaeroides containing different carotenoids yield different splitting energies, demonstrating that the coupling mechanism is sensitive to the electronic states in the light harvesting complexes. Plasmon–exciton coupling models reveal different coupling strengths depending on the molecular organization and the protein coverage, consistent with strong coupling. Strong coupling was also observed for self-assembling polypeptide maquettes that contain only chlorins. However, it is not observed for monolayers of bacteriochlorophyll, indicating that strong plasmon–exciton coupling is sensitive to the specific presentation of the pigment molecules. PMID:27689237

  4. Quantum phase transition in strongly correlated systems

    NASA Astrophysics Data System (ADS)

    Jiang, Longhua

    In this thesis, we investigated the strongly correlated phenomena in bilayer quantum Hall effect, inhomogeneous superconductivity and Boson Hubbard model. Bilayer quantum Hall system is studied in chapter 2. By using the Composite Boson (CB) theory developed by J. Ye, we derive the ground state, quasihole and a quasihole-pair wave functions from the CB theory and its dual action. We find that the ground state wave function is the product of two parts, one in the charge sector which is the well known Halperin's (111) wave function and the other in the spin sector which is non-trivial at any finite d due to the gapless mode. So the total groundstate wave function differs from the well known (111) wave function at any finite d. In addition to commonly known multiplicative factors, the quasihole and quasihole-pair wave functions also contain non-trivial normalization factors multiplying the correct ground state wave function. Then we continue to study the quantum phase transition from the excitonic superfluid (ESF) to a possible pseudo-spin density wave (PSDW) at some intermediate distances driven by the magneto-roton minimum collapsing at a finite wavevector. We analyze the properties of the PSDW and explicitly show that a square lattice is the favored lattice. We suggest that correlated hopping of vacancies in the active and passive layers in the PSDW state leads to very large and temperature-dependent drag, consistent with the experimental data. Comparisons with previous microscopic numerical calculations are made. Further experimental implications are given. In chapter 3, we investigate inhomogeneous superconductivity. Starting from the Ginzburg-Landau free energy describing the normal state to Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) state transition, we evaluate the free energy of seven most common lattice structures: stripe, square, triangular, Simple Cubic (SC), Face centered Cubic (FCC), Body centered Cubic (BCC) and Quasicrystal (QC). We find that the stripe

  5. Strong Seasonality and Interannual Recurrence in Marine Myovirus Communities

    PubMed Central

    Chow, C.-E. T.; Johannessen, T.; Fuhrman, J. A.; Thingstad, T. F.; Sandaa, R. A.

    2013-01-01

    The temporal community dynamics and persistence of different viral types in the marine environment are still mostly obscure. Polymorphism of the major capsid protein gene, g23, was used to investigate the community composition dynamics of T4-like myoviruses in a North Atlantic fjord for a period of 2 years. A total of 160 unique operational taxonomic units (OTUs) were identified by terminal restriction fragment length polymorphism (TRFLP) of the gene g23. Three major community profiles were identified (winter-spring, summer, and autumn), which resulted in a clear seasonal succession pattern. These seasonal transitions were recurrent over the 2 years and significantly correlated with progression of seawater temperature, Synechococcus abundance, and turbidity. The appearance of the autumn viral communities was concomitant with the occurrence of prominent Synechococcus blooms. As a whole, we found a highly dynamic T4-like viral community with strong seasonality and recurrence patterns. These communities were unexpectedly dominated by a group of persistently abundant viruses. PMID:23913432

  6. Correlated Fluctuations in Strongly Coupled Binary Networks Beyond Equilibrium

    NASA Astrophysics Data System (ADS)

    Dahmen, David; Bos, Hannah; Helias, Moritz

    2016-07-01

    Randomly coupled Ising spins constitute the classical model of collective phenomena in disordered systems, with applications covering glassy magnetism and frustration, combinatorial optimization, protein folding, stock market dynamics, and social dynamics. The phase diagram of these systems is obtained in the thermodynamic limit by averaging over the quenched randomness of the couplings. However, many applications require the statistics of activity for a single realization of the possibly asymmetric couplings in finite-sized networks. Examples include reconstruction of couplings from the observed dynamics, representation of probability distributions for sampling-based inference, and learning in the central nervous system based on the dynamic and correlation-dependent modification of synaptic connections. The systematic cumulant expansion for kinetic binary (Ising) threshold units with strong, random, and asymmetric couplings presented here goes beyond mean-field theory and is applicable outside thermodynamic equilibrium; a system of approximate nonlinear equations predicts average activities and pairwise covariances in quantitative agreement with full simulations down to hundreds of units. The linearized theory yields an expansion of the correlation and response functions in collective eigenmodes, leads to an efficient algorithm solving the inverse problem, and shows that correlations are invariant under scaling of the interaction strengths.

  7. Improving experimental phases for strong reflections prior to density modification

    SciTech Connect

    Uervirojnangkoorn, Monarin; Hilgenfeld, Rolf; Terwilliger, Thomas C.; Read, Randy J.

    2013-09-20

    Experimental phasing of diffraction data from macromolecular crystals involves deriving phase probability distributions. These distributions are often bimodal, making their weighted average, the centroid phase, improbable, so that electron-density maps computed using centroid phases are often non-interpretable. Density modification brings in information about the characteristics of electron density in protein crystals. In successful cases, this allows a choice between the modes in the phase probability distributions, and the maps can cross the borderline between non-interpretable and interpretable. Based on the suggestions by Vekhter [Vekhter (2005), Acta Cryst. D61, 899–902], the impact of identifying optimized phases for a small number of strong reflections prior to the density-modification process was investigated while using the centroid phase as a starting point for the remaining reflections. A genetic algorithm was developed that optimizes the quality of such phases using the skewness of the density map as a target function. Phases optimized in this way are then used in density modification. In most of the tests, the resulting maps were of higher quality than maps generated from the original centroid phases. In one of the test cases, the new method sufficiently improved a marginal set of experimental SAD phases to enable successful map interpretation. Lastly, a computer program,SISA, has been developed to apply this method for phase improvement in macromolecular crystallography.

  8. Improving experimental phases for strong reflections prior to density modification

    DOE PAGES

    Uervirojnangkoorn, Monarin; Hilgenfeld, Rolf; Terwilliger, Thomas C.; ...

    2013-09-20

    Experimental phasing of diffraction data from macromolecular crystals involves deriving phase probability distributions. These distributions are often bimodal, making their weighted average, the centroid phase, improbable, so that electron-density maps computed using centroid phases are often non-interpretable. Density modification brings in information about the characteristics of electron density in protein crystals. In successful cases, this allows a choice between the modes in the phase probability distributions, and the maps can cross the borderline between non-interpretable and interpretable. Based on the suggestions by Vekhter [Vekhter (2005), Acta Cryst. D61, 899–902], the impact of identifying optimized phases for a small number ofmore » strong reflections prior to the density-modification process was investigated while using the centroid phase as a starting point for the remaining reflections. A genetic algorithm was developed that optimizes the quality of such phases using the skewness of the density map as a target function. Phases optimized in this way are then used in density modification. In most of the tests, the resulting maps were of higher quality than maps generated from the original centroid phases. In one of the test cases, the new method sufficiently improved a marginal set of experimental SAD phases to enable successful map interpretation. Lastly, a computer program,SISA, has been developed to apply this method for phase improvement in macromolecular crystallography.« less

  9. Polaronic approach to strongly correlated electron systems with strong electron-phonon interaction

    NASA Astrophysics Data System (ADS)

    Makarov, I. A.; Shneyder, E. I.; Kozlov, P. A.; Ovchinnikov, S. G.

    2015-10-01

    The three-band p -d model of strongly correlated electrons interacting with optical phonons via diagonal and off-diagonal electron-phonon interactions is considered within the cluster perturbation theory. In the beginning, the exact diagonalization of the Hamiltonian of a CuO4 cluster results in the construction of local polaronic eigenstates |p > with hole numbers nh=0 ,1 ,2 per unit cell. The intercluster hoppings and interactions are exactly written in terms of Hubbard operators Xfp q=|p > at site f . The Fermi-type single-electron quasiparticle dispersion and spectral weight are calculated for the undoped antiferromagnetic parent insulator like La2CuO4 . The quasiparticle dispersion of Hubbard polarons is determined by a hybridization of the Hubbard fermion subbands with local Franck-Condon resonances so the main polaronic effect of the quasiparticle band structure is a splitting of the Hubbard bands on the number of Hubbard polaron subbands. Increasing of the EPI constant results in an increase of splitting, decrease of the subband width, transfer of the spectral weight to high-energy multiphonon excitations, and subsequent localization of the charge carriers. Herewith, the effect of such renormalization for the conduction band and the valence one differs depending on the ratio of the diagonal and off-diagonal EPI. In the framework of the GTB method, the Franck-Condon broadening of the spectral function of polaronic excitations is also reproduced for strongly correlated systems with strong electron-phonon interaction.

  10. NDR proteins

    PubMed Central

    Jones, Alan M

    2010-01-01

    N-myc downregulated (NDR) genes were discovered more than fifteen years ago. Indirect evidence support a role in tumor progression and cellular differentiation, but their biochemical function is still unknown. Our detailed analyses on Arabidopsis NDR proteins (deisgnated NDR-like, NDL) show their involvement in altering auxin transport, local auxin gradients and expression level of auxin transport proteins. Animal NDL proteins may be involved in membrane recycling of E-cadherin and effector for the small GTPase. In light of these findings, we hypothesize that NDL proteins regulate vesicular trafficking of auxin transport facilitator PIN proteins by biochemically alterating the local lipid environment of PIN proteins. PMID:20724844

  11. Is there a protein ligase?

    PubMed

    Erhan, S

    1976-01-01

    Results obtained from experiments dealing with mammalian, bacterial, phage and mitochondrial protein biosynthesis as well as certain enzymatically performed amino acid replacement studies on Kunitz trypsin inhibitor strongly suggest that protein ligation may be occuring in vivo. Amino acid substitution experiments prove the reversibility of endopeptidase reactions, and protein ligation is the reverse of endopeptidase reaction. These experiments are discussed in detail and the suggestion is made that ligation may also be useful in the repair of certain essential proteins which may become damaged.

  12. On strongly GA-convex functions and stochastic processes

    SciTech Connect

    Bekar, Nurgül Okur; Akdemir, Hande Günay; İşcan, İmdat

    2014-08-20

    In this study, we introduce strongly GA-convex functions and stochastic processes. We provide related well-known Kuhn type results and Hermite-Hadamard type inequality for strongly GA-convex functions and stochastic processes.

  13. On strongly GA-convex functions and stochastic processes

    NASA Astrophysics Data System (ADS)

    Bekar, Nurgül Okur; Akdemir, Hande Günay; Işcan, Imdat

    2014-08-01

    In this study, we introduce strongly GA-convex functions and stochastic processes. We provide related well-known Kuhn type results and Hermite-Hadamard type inequality for strongly GA-convex functions and stochastic processes.

  14. 7 CFR 51.906 - Well developed and strong.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 2 2012-01-01 2012-01-01 false Well developed and strong. 51.906 Section 51.906 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards....906 Well developed and strong. Well developed and strong means that the main and lateral stems...

  15. 7 CFR 51.906 - Well developed and strong.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 2 2011-01-01 2011-01-01 false Well developed and strong. 51.906 Section 51.906 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards....906 Well developed and strong. Well developed and strong means that the main and lateral stems...

  16. 7 CFR 51.906 - Well developed and strong.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Well developed and strong. 51.906 Section 51.906 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards....906 Well developed and strong. Well developed and strong means that the main and lateral stems...

  17. 7 CFR 51.906 - Well developed and strong.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 2 2014-01-01 2014-01-01 false Well developed and strong. 51.906 Section 51.906 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards... Vinifera Type) 1 Definitions § 51.906 Well developed and strong. Well developed and strong means that...

  18. 7 CFR 51.906 - Well developed and strong.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 2 2013-01-01 2013-01-01 false Well developed and strong. 51.906 Section 51.906 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards... Vinifera Type) 1 Definitions § 51.906 Well developed and strong. Well developed and strong means that...

  19. Cantharidin, a protein phosphatase inhibitor, strongly upregulates detoxification enzymes in the Arabidopsis proteome

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cantharidin is a potent natural herbicide. This work was conducted to probe its mode of action. We previously published its effect on transcription of plant genes (mRNA production) with transcriptomic methods. This paper follows up and looks at cantharidin effects translation of mRNA using proteom...

  20. Proteins (image)

    MedlinePlus

    ... is an important nutrient that builds muscles and bones and provides energy. Protein can help with weight control because it helps you feel full and satisfied from your meals. The healthiest proteins are the leanest. This means ...

  1. Binding constants of membrane-anchored receptors and ligands depend strongly on the nanoscale roughness of membranes.

    PubMed

    Hu, Jinglei; Lipowsky, Reinhard; Weikl, Thomas R

    2013-09-17

    Cell adhesion and the adhesion of vesicles to the membranes of cells or organelles are pivotal for immune responses, tissue formation, and cell signaling. The adhesion processes depend sensitively on the binding constant of the membrane-anchored receptor and ligand proteins that mediate adhesion, but this constant is difficult to measure in experiments. We have investigated the binding of membrane-anchored receptor and ligand proteins with molecular dynamics simulations. We find that the binding constant of the anchored proteins strongly decreases with the membrane roughness caused by thermally excited membrane shape fluctuations on nanoscales. We present a theory that explains the roughness dependence of the binding constant for the anchored proteins from membrane confinement and that relates this constant to the binding constant of soluble proteins without membrane anchors. Because the binding constant of soluble proteins is readily accessible in experiments, our results provide a useful route to compute the binding constant of membrane-anchored receptor and ligand proteins.

  2. Aeolotopic interactions of globular proteins

    PubMed Central

    Lomakin, Aleksey; Asherie, Neer; Benedek, George B.

    1999-01-01

    Protein crystallization, aggregation, liquid–liquid phase separation, and self-assembly are important in protein structure determination in the industrial processing of proteins and in the inhibition of protein condensation diseases. To fully describe such phase transformations in globular protein solutions, it is necessary to account for the strong spatial variation of the interactions on the protein surface. One difficulty is that each globular protein has its own unique surface, which is crucial for its biological function. However, the similarities amongst the macroscopic properties of different protein solutions suggest that there may exist a generic model that is capable of describing the nonuniform interactions between globular proteins. In this paper we present such a model, which includes the short-range interactions that vary from place to place on the surface of the protein. We show that this aeolotopic model [from the Greek aiolos (“variable”) and topos (“place”)] describes the phase diagram of globular proteins and provides insight into protein aggregation and crystallization. PMID:10449715

  3. Protein Structure

    ERIC Educational Resources Information Center

    Asmus, Elaine Garbarino

    2007-01-01

    Individual students model specific amino acids and then, through dehydration synthesis, a class of students models a protein. The students clearly learn amino acid structure, primary, secondary, tertiary, and quaternary structure in proteins and the nature of the bonds maintaining a protein's shape. This activity is fun, concrete, inexpensive and…

  4. 76 FR 52934 - Request for Comments: Public Input for the Launch of the Strong Cities, Strong Communities...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-24

    ... Economic Development Administration Request for Comments: Public Input for the Launch of the Strong Cities, Strong Communities Visioning Challenge AGENCY: Economic Development Administration, U.S. Department of..., 2011, the Economic Development Administration (EDA) published a Federal Register notice...

  5. Strong bending of purple membranes in the M-state.

    PubMed

    Porschke, Dietmar

    2003-08-15

    Structure changes of purple membranes during the photocycle were analysed in solution by measurements of the electric dichroism. The D96N-mutant was used to characterize the M-state at neutral pH. The transition from the resting state to 61% photo-stationary M-state is associated with a strong reduction of the dichroism decay time constant by a factor of approximately 2. Because the change of the time constant is independent of the bacteriorhodopsin concentration, the effect is not attributed to light-induced dissociation but to light-induced bending of purple membranes. After termination of light-activation the dichroism decay of the resting state is restored with a time constant close to that of the M-state decay, which is more than two orders of magnitude slower than proton transfer to the bulk. Thus, bending is not due to asymmetric protonation but to the structure of the M-state. A very similar reduction of decay time constants at a corresponding degree of light-activation was found for wild-type bacteriorhodopsin at pH-values 7.8-9.3, where the lifetime of the M-state is extended. Light-induced bending is also reflected in changes of the stationary dichroism, whereas the overall permanent dipole moment remains almost constant, suggesting compensation of changes in molecular and global contributions. Bead model simulations indicate that disks of approximately 1 microm diameter are bent at a degree of photo-activation of 61% to a radius of approximately 0.25 microm, assuming a cylindrical bending modus. The large light-induced bending effect is consistent with light-induced opening of the protein on the cytoplasmic side of the membrane detected by electron crystallography, which is amplified due to coupling of monomers in the membrane. Bending may function as a mechanical signal.

  6. Traces of strong selective pressures in the genomes of C4 grasses.

    PubMed

    Christin, Pascal-Antoine

    2017-01-01

    C4 photosynthesis is nature's response to CO2 limitations, and evolved recurrently in several groups of plants. To identify genes related to C4 photosynthesis, Huang et al. looked for evidence of past episodes of adaptive evolution in the genomes of C4 grasses. They identified a large number of candidate genes that evolved under divergent selection, indicating that, besides alterations to expression patterns, the history of C4 involved strong selection on protein-coding sequences.

  7. Toponomics: studying protein-protein interactions and protein networks in intact tissue.

    PubMed

    Pierre, Sandra; Scholich, Klaus

    2010-04-01

    The function of a protein is determined on several levels including the genome, transcriptome, proteome, and the recently introduced toponome. The toponome describes the topology of all proteins, protein complexes and protein networks which constitute and influence the microenvironment of a given protein. It has long been known that cellular function or dysfunction of proteins strongly depends on their microenvironment and even small changes in protein arrangements can dramatically alter their activity/function. Thus, deciphering the topology of the multi-dimensional networks which control normal and disease-related pathways will give a better understanding of the mechanisms underlying disease development. While various powerful proteomic tools allow simultaneous quantification of proteins, only a limited number of techniques are available to visualize protein networks in intact cells and tissues. This review discusses a novel approach to map and decipher functional molecular networks of proteins in intact cells or tissues. Multi-epitope-ligand-cartography (MELC) is an imaging technology that identifies and quantifies protein networks at the subcellular level of morphologically-intact specimens. This immunohistochemistry-based method allows serial visualization and biomathematical analysis of up to 100 cellular components using fluorescence-labelled tags. The resulting toponome maps, simultaneously ranging from the subcellular to the supracellular scale, have the potential to provide the basis for a mathematical description of the dynamic topology of protein networks, and will complement current proteomic data to enhance the understanding of physiological and pathophysiological cell functions.

  8. Simple but Strong: A Mussel-Inspired Hot Curing Adhesive Based on Polyvinyl Alcohol Backbone.

    PubMed

    Mu, Youbing; Wan, Xiaobo

    2016-03-01

    The strong adhesion ability of mussel foot-byssal proteins (Mfps) has inspired scientists to develop novel materials for strong and reversible adhesion, coating, antifouling, and many other applications. However, in many cases, the high costs and the tedious preparation steps of such bioinspired materials hamper the process to push them into practical application. Here a simple but effective way (one step) is presented to synthesize a mussel-inspired glue from two cheap commercially available materials: polyvinyl alcohol (PVA) and 3,4-dihydroxybenzaldehyde (DBA). This bioinspired hot curing adhesive exhibits a strong bonding ability as high as 17.3 MPa on stainless steel surfaces, which surpasses most of the commercially available adhesives.

  9. Assay and characterization of a strong promoter element from B. subtilis.

    PubMed

    Zhang, Ai-Ling; Liu, Hui; Yang, Ming-Ming; Gong, Yue-Sheng; Chen, Hong

    2007-03-02

    A new strong promoter fragment isolated from Bacillus subtilis was identified and characterized. Using the heat stable beta-galactosidase as reporter, the promoter fragment exhibited high expression strength both in Escherichia coli and B. subtilis. The typical prokaryotic promoter conservation regions were found in the promoter fragment and the putative promoter was identified as the control element of yxiE gene via sequencing assay and predication of promoter. To further verify and characterize the cloned strong promoter, the putative promoter was sub-cloned and the beta-Gal directed by the promoters was high-level expressed both in E. coli and B. subtilis. By means of the isolated promoter, an efficient expression system was developed in B. subtilis and the benefit and usefulness was demonstrated through expression of three heterologous and homogenous proteins. Thus, we identified a newly strong promoter of B. subtilis and provided a robust expression system for genetic engineering of B. subtilis.

  10. Protein-protein interactions in complex cosolvent solutions.

    PubMed

    Javid, Nadeem; Vogtt, Karsten; Krywka, Chris; Tolan, Metin; Winter, Roland

    2007-04-02

    The effects of various kosmotropic and chaotropic cosolvents and salts on the intermolecular interaction potential of positively charged lysozyme is evaluated at varying protein concentrations by using synchrotron small-angle X-ray scattering in combination with liquid-state theoretical approaches. The experimentally derived static structure factors S(Q) obtained without and with added cosolvents and salts are analysed with a statistical mechanical model based on the Derjaguin-Landau-Verwey-Overbeek (DLVO) potential, which accounts for repulsive and attractive interactions between the protein molecules. Different cosolvents and salts influence the interactions between protein molecules differently as a result of changes in the hydration level or solvation, in charge screening, specific adsorption of the additives at the protein surface, or increased hydrophobic interactions. Intermolecular interaction effects are significant above protein concentrations of 1 wt %, and with increasing protein concentration, the repulsive nature of the intermolecular pair potential V(r) increases markedly. Kosmotropic cosolvents like glycerol and sucrose exhibit strong concentration-dependent effects on the interaction potential, leading to an increase of repulsive forces between the protein molecules at low to medium high osmolyte concentrations. Addition of trifluoroethanol exhibits a multiphasic effect on V(r) when changing its concentration. Salts like sodium chloride and potassium sulfate exhibit strong concentration-dependent changes of the interaction potential due to charge screening of the positively charged protein molecules. Guanidinium chloride (GdmCl) at low concentrations exhibits a similar charge-screening effect, resulting in increased attractive interactions between the protein molecules. At higher GdmCl concentrations, V(r) becomes more repulsive in nature due to the presence of high concentrations of Gdm(+) ions binding to the protein molecules. Our findings also

  11. Therapeutic proteins.

    PubMed

    Dimitrov, Dimiter S

    2012-01-01

    Protein-based therapeutics are highly successful in clinic and currently enjoy unprecedented recognition of their potential. More than 100 genuine and similar number of modified therapeutic proteins are approved for clinical use in the European Union and the USA with 2010 sales of US$108 bln; monoclonal antibodies (mAbs) accounted for almost half (48%) of the sales. Based on their pharmacological activity, they can be divided into five groups: (a) replacing a protein that is deficient or abnormal; (b) augmenting an existing pathway; (c) providing a novel function or activity; (d) interfering with a molecule or organism; and (e) delivering other compounds or proteins, such as a radionuclide, cytotoxic drug, or effector proteins. Therapeutic proteins can also be grouped based on their molecular types that include antibody-based drugs, Fc fusion proteins, anticoagulants, blood factors, bone morphogenetic proteins, engineered protein scaffolds, enzymes, growth factors, hormones, interferons, interleukins, and thrombolytics. They can also be classified based on their molecular mechanism of activity as (a) binding non-covalently to target, e.g., mAbs; (b) affecting covalent bonds, e.g., enzymes; and (c) exerting activity without specific interactions, e.g., serum albumin. Most protein therapeutics currently on the market are recombinant and hundreds of them are in clinical trials for therapy of cancers, immune disorders, infections, and other diseases. New engineered proteins, including bispecific mAbs and multispecific fusion proteins, mAbs conjugated with small molecule drugs, and proteins with optimized pharmacokinetics, are currently under development. However, in the last several decades, there are no conceptually new methodological developments comparable, e.g., to genetic engineering leading to the development of recombinant therapeutic proteins. It appears that a paradigm change in methodologies and understanding of mechanisms is needed to overcome major

  12. Strong-field ionization via a high-order Coulomb-corrected strong-field approximation

    NASA Astrophysics Data System (ADS)

    Klaiber, Michael; Daněk, Jiří; Yakaboylu, Enderalp; Hatsagortsyan, Karen Z.; Keitel, Christoph H.

    2017-02-01

    Signatures of the Coulomb corrections in the photoelectron momentum distribution during laser-induced ionization of atoms or ions in tunneling and multiphoton regimes are investigated analytically in the case of a one-dimensional problem. A high-order Coulomb-corrected strong-field approximation is applied, where the exact continuum state in the S matrix is approximated by the eikonal Coulomb-Volkov state including the second-order corrections to the eikonal. Although without high-order corrections our theory coincides with the known analytical R -matrix (ARM) theory, we propose a simplified procedure for the matrix element derivation. Rather than matching the eikonal Coulomb-Volkov wave function with the bound state as in the ARM theory to remove the Coulomb singularity, we calculate the matrix element via the saddle-point integration method by time as well as by coordinate, and in this way avoiding the Coulomb singularity. The momentum shift in the photoelectron momentum distribution with respect to the ARM theory due to high-order corrections is analyzed for tunneling and multiphoton regimes. The relation of the quantum corrections to the tunneling delay time is discussed.

  13. Review fifteen years of search for strong nucleosomes.

    PubMed

    Trifonov, Edward N; Nibhani, Reshma

    2015-08-01

    Don Crothers, Mikael Kubista, Jon Widom, and their teams have been first to look for strong nucleosomes, in a bid to reveal the nucleosome positioning pattern(s) carried by the nucleosome DNA sequences. They were first to demonstrate that the nucleosome stability correlates with 10-11 base sequence periodicity, and that the strong nucleosomes localize preferentially in centromeres. This review describes these findings and their connection to recent discovery of the strong nucleosomes (SNs) with visibly periodic nucleosome DNA sequences.

  14. A brief introduction to the strong CP problem

    SciTech Connect

    Wu, Dan-di Melbourne Univ., Parkville . School of Physics)

    1991-09-01

    The present status of the strong CP problem is briefly reviewed in a heuristic way. A crisis in EDMN calculation is explained. The equation of vacuum alignment obtained by the author and collaborators last year put a constraint on strong CP parameters. Thus the strong CP will be forced to vanish in one of the three scenarios characterized by axion, zero quark mass, and vanishing quark condensate. 12 refs.

  15. Suppression of Rayleigh Taylor instability in strongly coupled plasmas

    SciTech Connect

    Das, Amita; Kaw, Predhiman

    2014-06-15

    The Rayleigh Taylor instability in a strongly coupled plasma medium has been investigated using the equations of generalized hydrodynamics. It is demonstrated that the visco-elasticity of the strongly coupled medium due to strong inter particle correlations leads to a suppression of the Rayleigh Taylor instability unless certain threshold conditions are met. The relevance of these results to experiments on laser compression of matter to high densities including those related to inertial confinement fusion using lasers has also been shown.

  16. Energy Spectra of Strongly Stratified and Rotating Turbulence

    NASA Technical Reports Server (NTRS)

    Mahalov, Alex; Nicolaenko, Basil; Zhou, Ye

    1998-01-01

    Turbulence under strong stratification and rotation is usually characterized as quasi-two dimensional turbulence. We develop a "quasi-two dimensional" energy spectrum which changes smoothly between the Kolmogorov -5/3 law (no stratification), the -2 scalings of Zhou for the case of strong rotation, as well as the -2 scalings for the case of strong rotation and stratification. For strongly stratified turbulence, the model may give the -2 scaling predicted by Herring; and the -5/3 scaling indicated by some mesoscale observations.

  17. A perspective on the history of Strong Motion Seismology

    NASA Astrophysics Data System (ADS)

    Aki, Keiiti

    2003-05-01

    Today, Strong Motion Seismology is widely recognized as an effective bridge between earthquake information from earth sciences and the engineering practice for mitigating the earthquake hazard. This paper describes how this development of Strong Motion Seismology occurred in a relatively short time span of around three decades. We also discuss the emergence of the concept of the master model for a broader integration of earthquake information, of which Strong Motion Seismology is a key part, promoted at the Southern California Earthquake Center (SCEC) in the past decade. We shall conclude the paper with a future perspective for Strong Motion Seismology.

  18. Classical and quantum distinctions between weak and strong coupling

    NASA Astrophysics Data System (ADS)

    Rahimzadeh-Kalaleh Rodriguez, Said

    2016-03-01

    Coupled systems subject to dissipation exhibit two different regimes known as weak coupling and strong coupling. Two damped coupled harmonic oscillators (CHOs) constitute a model system where the key features of weak and strong coupling can be identified. Several of these features are common to classical and quantum systems, as a number of quantum-classical correspondences have shown. However, the condition defining the boundary between weak and strong coupling is distinct in classical and quantum formalisms. Here we describe the origin of two widely used definitions of strong coupling. Using a classical CHO model, we show that energy exchange cycles and avoided resonance crossings signal the onset of strong coupling according to one criterion. From the classical CHO model we derive a non-Hermitian Hamiltonian describing open quantum systems. Based on the analytic properties of the Hamiltonian, we identify the boundary between weak and strong coupling with a different feature: a non-Hermitian degeneracy known as the exceptional point. For certain parameter ranges the classical and quantum criterion for strong coupling coincide; for other ranges they do not. Examples of systems in strong coupling according to one or another criterion, but not both, are illustrated. The framework here presented is suitable for introducing graduate or advanced undegraduate students to the basic properties of strongly coupled systems, as well as to the similarities and subtle differences between classical and quantum descriptions of coupled dissipative systems.

  19. Electron Dynamics in Nanostructures in Strong Laser Fields

    SciTech Connect

    Kling, Matthias

    2014-09-11

    The goal of our research was to gain deeper insight into the collective electron dynamics in nanosystems in strong, ultrashort laser fields. The laser field strengths will be strong enough to extract and accelerate electrons from the nanoparticles and to transiently modify the materials electronic properties. We aimed to observe, with sub-cycle resolution reaching the attosecond time domain, how collective electronic excitations in nanoparticles are formed, how the strong field influences the optical and electrical properties of the nanomaterial, and how the excitations in the presence of strong fields decay.

  20. Flow behavior of mixed-protein incipient gels

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Strong protein gel networks may result from synergistic interactions with other proteins or food materials above that achievable with a single protein alone. We determined varying flow and viscoelastic behavior of calcium caseinate (CC) or whey protein isolate (WPI) mixed with egg albumin (EA), fish...

  1. Protein Dynamics in Enzymology

    NASA Astrophysics Data System (ADS)

    Brooks, , III

    2001-03-01

    Enzymes carry-out the chemical activity essential for living processes by providing particular structural arrangements of chemically functional moieties through the structure of their constituent proteins. They are suggested to be optimized through evolution to specifically bind the transition state for the chemical processes they participate in, thereby enhancing the rate of these chemical events by 6-12 orders of magnitude. However, proteins are malleable and fluctuating many-body systems and may also utilize coupling between motional processes with catalysis to regulate or promote these processes. Our studies are aimed at exploring the hypothesis that motions of the protein couple distant regions of the molecule to assist catalytic processes. We demonstrate, through the use of molecular simulations, that strongly coupled motions occur in regions of protein molecules distant in sequence and space from each other, and the enzyme’s active site, when the protein is in a reactant state. Further, we find that the presence of this coupling disappears in complexes no longer reactive-competent, i.e., for product configurations and mutant sequences. The implications of these findings and aspects of evolutionary relationships and mutational studies which support the coupling hypothesis will be discussed in the context of our work on dihydrofolate reductase.

  2. Byelyankacin: a novel melanogenesis inhibitor produced by Enterobacter sp. B20.

    PubMed

    Takahashi, Senji; Iwai, Hiroki; Kosaka, Kunio; Miyazaki, Toshitsugu; Osanai, Yuko; Arao, Nakako; Tanaka, Kouichi; Nagai, Koji; Nakagawa, Akira

    2007-11-01

    A novel melanogenesis inhibitor, byelyankacin (1), was isolated from the fermentation broth of a bacterial strain. The producing organism, designated B20, was identified as a member of the genus Enterobacter based on taxonomic characteristics. 1 was obtained as a white powder from the culture medium by solvent extraction and serial chromatographic purification. The structure of 1 was determined as (E)-4-(2-isocyanovinyl)phenyl alpha-L-rhamnopyranoside on the basis of spectroscopic data. 1 potently inhibited mushroom tyrosinase and melanogenesis of B16-2D2 melanoma cells with IC50 value of 2.1 nM and 30 nM, respectively.

  3. Activation of macrophages by an exopolysaccharide isolated from Antarctic Psychrobacter sp. B-3

    NASA Astrophysics Data System (ADS)

    Yu, Leiye; Sun, Guojie; Wei, Jingfang; Wang, Yingze; Du, Chao; Li, Jiang

    2016-09-01

    An exopolysaccharide (EPS) was isolated and purified from an Antarctic psychrophilic bacterium B-3, identified as Psychrobacter sp., and the activation of RAW264.7 cells by B-3 EPS was investigated. The results show that B-3 EPS, over a certain concentration range, promoted cell viability, nitric oxide production, tumor necrosis factor (TNF)α secretion, and phagocytic ability. Furthermore, TAK-242, an inhibitor of the toll-like receptor 4 (TLR4) significantly reduced nitric oxide production by these cells after stimulation with B-3 EPS. Moreover, B-3 EPS induced p65 phosphorylation and IκBα degradation in these cells. In conclusion, B-3 EPS might have activated RAW264.7 cells by combining with TLR4 on cell surface and triggering activation of NF-κB signaling pathways, implying that this EPS could activate macrophages and regulate initial immune response.

  4. The Strong-Inference Protocol: Not Just for Grant Proposals

    ERIC Educational Resources Information Center

    Hiebert, Sara M.

    2007-01-01

    The strong-inference protocol puts into action the important concepts in Platt's often-assigned, classic paper on the strong-inference method (10). Yet, perhaps because students are frequently performing experiments with known outcomes, the protocols they write as undergraduates are usually little more than step-by-step instructions for performing…

  5. Strong motion instrumentation of an RC building structure

    USGS Publications Warehouse

    Li, H.-J.; Celebi, M.

    2001-01-01

    The strong-motion instrumentation scheme of a reinforced concrete building observed by California Strong-Motion Instrumentation Program (CSMIP) is introduced in this paper. The instrumented building is also described and the recorded responses during 1994 Northridge earthquake are provided.

  6. Strong Couplings of Three Mesons with Charm(ing) Involvement

    NASA Astrophysics Data System (ADS)

    Lucha, Wolfgang; Melikhov, Dmitri; Sazdjian, Hagop; Simula, Silvano

    2017-03-01

    We determine the strong couplings of three mesons that involve, at least, one ηc or J/ψ meson, within the framework of a constituent-quark model by means of relativistic dispersion formulations. For strong couplings of J/ψ mesons to two charmed mesons, our approach leads to predictions roughly twice as large as those arising from QCD sum rules.

  7. Plasma transport theory spanning weak to strong coupling

    SciTech Connect

    Daligault, Jérôme; Baalrud, Scott D.

    2015-06-29

    We describe some of the most striking characteristics of particle transport in strongly coupled plasmas across a wide range of Coulomb coupling strength. We then discuss the effective potential theory, which is an approximation that was recently developed to extend conventional weakly coupled plasma transport theory into the strongly coupled regime in a manner that is practical to evaluate efficiently.

  8. Quantum Liquid Crystal Phases in Strongly Correlated Fermionic Systems

    ERIC Educational Resources Information Center

    Sun, Kai

    2009-01-01

    This thesis is devoted to the investigation of the quantum liquid crystal phases in strongly correlated electronic systems. Such phases are characterized by their partially broken spatial symmetries and are observed in various strongly correlated systems as being summarized in Chapter 1. Although quantum liquid crystal phases often involve…

  9. Theory and Meaning in Counseling Research: Comment on Strong (1991).

    ERIC Educational Resources Information Center

    Patton, Michael J.; Jackson, Aaron P.

    1991-01-01

    Responds to previous article by Strong on theory-driven science and naive empiricism in counseling psychology. Questions distinction Strong makes between theory-driven science and naive empiricism. Argues that more relevant debate is between qualitative and quantitative approaches to counseling research. Presents some differences between the two…

  10. 75 FR 47316 - Centennial Challenges 2010 Strong Tether Challenge

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-05

    .... 2451 (314)(d). The 2010 Strong Tether Challenge is scheduled and teams that wish to compete may... designed to encourage development of very strong, lightweight material for use in a multitude of structural... prize competitors must (1) register and comply with all requirements in the rules and team agreement;...

  11. Whey Protein

    MedlinePlus

    ... inflammation (polymyalgia rheumatica). Taking whey protein in a dairy product twice daily for 8 weeks does not improve muscle function, walking speed, or other movement tests in people with polymyalgia rheumatica. Other conditions. More evidence is needed to rate whey protein for these uses.

  12. Correlations of Ventricular Enlargement with Rheologically Active Surfactant Proteins in Cerebrospinal Fluid

    PubMed Central

    Schob, Stefan; Weiß, Alexander; Dieckow, Julia; Richter, Cindy; Pirlich, Mandy; Voigt, Peter; Surov, Alexey; Hoffmann, Karl-Titus; Quaeschling, Ulf; Preuß, Matthias

    2017-01-01

    Purpose: Surfactant proteins (SPs) are involved in the regulation of rheological properties of body fluids. Concentrations of SPs are altered in the cerebrospinal fluid (CSF) of hydrocephalus patients. The common hallmark of hydrocephalus is enlargement of the brain ventricles. The relationship of both phenomena has not yet been investigated. The aim of this study was to evaluate the association between SP concentrations in the CSF and enlargement of the brain ventricles. Procedures: Ninty-six individuals (41 healthy subjects and 55 hydrocephalus patients) were included in this retrospective analysis. CSF specimens were analyzed for SP-A, SP-B, SP-C and SP-D concentrations by use of enzyme linked immunosorbent assays (ELISA). Ventricular enlargement was quantified in T2 weighted (T2w) magnetic resonance imaging (MRI) sections using an uni-dimensional (Evans’ Index) and a two-dimensional approach (lateral ventricles area index, LVAI). Results: CSF-SP concentrations (mean ± standard deviation in ng/ml) were as follows: SP-A 0.71 ± 0.58, SP-B 0.18 ± 0.43, SP-C 0.89 ± 0.77 and SP-D 7.4 ± 5.4. Calculated values of Evans’ Index were 0.37 ± 0.11, a calculation of LVAI resulted in 0.18 ± 0.15 (each mean ± standard deviation). Significant correlations were identified for Evans’ Index with SP-A (r = 0.388, p < 0.001) and SP-C (r = 0.392, p < 0.001), LVAI with SP-A (r = 0.352, p = 0.001), SP-C (r = 0.471, p < 0.001) and SP-D (r = 0.233, p = 0.025). Furthermore, SP-C showed a clear inverse correlation with age (r = −0.357, p = 0.011). Conclusion: The present study confirmed significant correlations between SPs A, C and D in the CSF with enlargement of the inner CSF spaces. In conclusion, SPs clearly play an important role for CSF rheology. CSF rheology is profoundly altered in hydrocephalic diseases, however, diagnosis and therapy of hydrocephalic conditions are still almost exclusively based on ventricular enlargement. Until now it was unclear, whether the

  13. Structural Symmetry in Membrane Proteins.

    PubMed

    Forrest, Lucy R

    2015-01-01

    Symmetry is a common feature among natural systems, including protein structures. A strong propensity toward symmetric architectures has long been recognized for water-soluble proteins, and this propensity has been rationalized from an evolutionary standpoint. Proteins residing in cellular membranes, however, have traditionally been less amenable to structural studies, and thus the prevalence and significance of symmetry in this important class of molecules is not as well understood. In the past two decades, researchers have made great strides in this area, and these advances have provided exciting insights into the range of architectures adopted by membrane proteins. These structural studies have revealed a similarly strong bias toward symmetric arrangements, which were often unexpected and which occurred despite the restrictions imposed by the membrane environment on the possible symmetry groups. Moreover, membrane proteins disproportionately contain internal structural repeats resulting from duplication and fusion of smaller segments. This article discusses the types and origins of symmetry in membrane proteins and the implications of symmetry for protein function.

  14. Towards an integrated European strong motion data distribution

    NASA Astrophysics Data System (ADS)

    Luzi, Lucia; Clinton, John; Cauzzi, Carlo; Puglia, Rodolfo; Michelini, Alberto; Van Eck, Torild; Sleeman, Reinhoud; Akkar, Sinan

    2013-04-01

    Recent decades have seen a significant increase in the quality and quantity of strong motion data collected in Europe, as dense and often real-time and continuously monitored broadband strong motion networks have been constructed in many nations. There has been a concurrent increase in demand for access to strong motion data not only from researchers for engineering and seismological studies, but also from civil authorities and seismic networks for the rapid assessment of ground motion and shaking intensity following significant earthquakes (e.g. ShakeMaps). Aside from a few notable exceptions on the national scale, databases providing access to strong motion data has not appeared to keep pace with these developments. In the framework of the EC infrastructure project NERA (2010 - 2014), that integrates key research infrastructures in Europe for monitoring earthquakes and assessing their hazard and risk, the network activity NA3 deals with the networking of acceleration networks and SM data. Within the NA3 activity two infrastructures are being constructed: i) a Rapid Response Strong Motion (RRSM) database, that following a strong event, automatically parameterises all available on-scale waveform data within the European Integrated waveform Data Archives (EIDA) and makes the waveforms easily available to the seismological community within minutes of an event; and ii) a European Strong Motion (ESM) database of accelerometric records, with associated metadata relevant to earthquake engineering and seismology research communities, using standard, manual processing that reflects the state of the art and research needs in these fields. These two separate repositories form the core infrastructures being built to distribute strong motion data in Europe in order to guarantee rapid and long-term availability of high quality waveform data to both the international scientific community and the hazard mitigation communities. These infrastructures will provide the access to

  15. Protein Adsorption in Three Dimensions

    PubMed Central

    Vogler, Erwin A.

    2011-01-01

    initially-adsorbed protein. Interphase protein concentration CI increases as VI decreases, resulting in slow reduction in interfacial energetics. Steady-state is governed by a net partition coefficient P=(/CBCI). In the process of occupying space within the interphase, adsorbing protein molecules must displace an equivalent volume of interphase water. Interphase water is itself associated with surface-bound water through a network of transient hydrogen bonds. Displacement of interphase water thus requires an amount of energy that depends on the adsorbent surface chemistry/energy. This “adsorption-dehydration” step is the significant free-energy cost of adsorption that controls the maximum amount of protein that can be adsorbed at steady state to a unit adsorbent-surface area (the adsorbent capacity). As adsorbent hydrophilicity increases, protein adsorption monotonically decreases because the energetic cost of surface dehydration increases, ultimately leading to no protein adsorption near an adsorbent water wettability (surface energy) characterized by a water contact angle θ → 65°. Consequently, protein does not adsorb (accumulate at interphase concentrations greater than bulk solution) to more hydrophilic adsorbents exhibiting θ < 65° . For adsorbents bearing strong Lewis acid/base chemistry such as ion-exchange resins, protein/surface interactions can be highly favorable, causing protein to adsorb in multilayers in a relatively thick interphase. A straightforward, three-component free energy relationship captures salient features of protein adsorption to all surfaces predicting that the overall free energy of protein adsorption ΔGadso is a relatively small multiple of thermal energy for any surface chemistry (except perhaps for bioengineered surfaces bearing specific ligands for adsorbing protein) because a surface chemistry that interacts chemically with proteins must also interact with water through hydrogen bonding. In this way, water moderates protein

  16. Formation of a Polycomb-Domain in the Absence of Strong Polycomb Response Elements

    PubMed Central

    De, Sandip; Mitra, Apratim; Cheng, Yuzhong; Pfeifer, Karl; Kassis, Judith A.

    2016-01-01

    Polycomb group response elements (PREs) in Drosophila are DNA-elements that recruit Polycomb proteins (PcG) to chromatin and regulate gene expression. PREs are easily recognizable in the Drosophila genome as strong peaks of PcG-protein binding over discrete DNA fragments; many small but statistically significant PcG peaks are also observed in PcG domains. Surprisingly, in vivo deletion of the four characterized strong PREs from the PcG regulated invected-engrailed (inv-en) gene complex did not disrupt the formation of the H3K27me3 domain and did not affect inv-en expression in embryos or larvae suggesting the presence of redundant PcG recruitment mechanism. Further, the 3D-structure of the inv-en domain was only minimally altered by the deletion of the strong PREs. A reporter construct containing a 7.5kb en fragment that contains three weak peaks but no large PcG peaks forms an H3K27me3 domain and is PcG-regulated. Our data suggests a model for the recruitment of PcG-complexes to Drosophila genes via interactions with multiple, weak PREs spread throughout an H3K27me3 domain. PMID:27466807

  17. Engineering Yarrowia lipolytica to express secretory invertase with strong FBA1IN promoter.

    PubMed

    Hong, Seung-Pyo; Seip, John; Walters-Pollak, Dana; Rupert, Ross; Jackson, Raymond; Xue, Zhixiong; Zhu, Quinn

    2012-02-01

    Oleaginous yeast Yarrowia lipolytica is an important host for the production of lipid-derived compounds or heterologous proteins. Selection of strong promoters and effective expression systems is critical for heterologous protein secretion. To search for a strong promoter in Y. lipolytica, activities of FBA1, TDH1 and GPM1 promoters were compared to that of TEF1 promoter by constructing GUS reporter fusions. The FBA1 promoter activity was 2.2 and 5.5 times stronger than the TDH1 and GPM1 promoters, respectively. The FBA1IN promoter (FBA1 sequence of -826 to +169) containing an intron (+64 to +165) showed five-fold higher expression than the FBA1 promoter (-831 to -1). The transcriptional enhancement by the 5'-region within the FBA1 gene was confirmed by GPM1::FBA1 chimeric promoter construction. Using the strong FBA1IN promoter, four different S. cerevisiae SUC2 expression cassettes were tested for the SUC+ phenotype in Y. lipolytica. Functional invertase secretion was facilitated by the Xpr2 prepro-region with an additional 13 amino acids of mature Xpr2, or by the native Suc2 signal sequence. However, these two secretory signals in tandem, or the mature Suc2 with no secretory signal, did not direct secretion of functional invertase. Unlike previously reported Y. lipolytica SUC+ strains, our engineered stains secreted most of invertase into the medium.

  18. 78 FR 27249 - Announcement of Funding Awards for Fiscal Year 2012/2013; Strong Cities, Strong Communities...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-09

    ..., Development and Research (PD&R), U.S. Department of Housing and Urban Development, Room 8116, 451 Seventh... Council on Strong Cities, Strong Communities and PD&R administers this program. In addition to this program, PD&R administers another key component of the White House SC2 initiative-- the SC2...

  19. Acceleration of Polarized Beams Using Multiple Strong Partial Siberian Snakes

    NASA Astrophysics Data System (ADS)

    Roser, T.; Ahrens, L. A.; Bai, M.; Courant, E. D.; Glenn, J. W.; Gupta, R. C.; Huang, H.; Luccio, A. U.; Mackay, W. W.; Tsoupas, N.; Willen, E.; Okamura, M.; Takano, J.

    2005-08-01

    Acceleration of polarized protons in the energy range of 5 to 25 GeV is particularly difficult since depolarizing spin resonances are strong enough to cause significant depolarization, but full Siberian snakes cause intolerably large orbit excursions. Using a 20 - 30 % partial Siberian snake, both imperfection and intrinsic resonances can be overcome. Such a strong partial Siberian snake was designed for the Brookhaven AGS using a dual pitch helical super-conducting dipole. Multiple strong partial snakes are also discussed for spin matching at beam injection and extraction.

  20. Strongly Interacting Fermi Gases: Current Issues and Future Prospects

    NASA Astrophysics Data System (ADS)

    Ho, Tin-Lun Jason

    2005-03-01

    There has been rapid development in the study of interacting atomic Fermi gases last year. In this talk, I shall discuss the issues brought forth by current experiments with regard to the nature of the newly found pair condensate, the universal thermodynamic and dynamical features in strongly interacting regime, and new methods of probing strongly interacting physics not possible in solid state environment. In the last part of the talk, I shall discuss the exciting theoretical possibilities associating with the latest experimental progress on producing molecules with higher orbital angular momentum, and on strongly interacting Fermi gases in optical lattices. In collaboration with Roberto Diener.

  1. Black hole tidal charge constrained by strong gravitational lensing

    NASA Astrophysics Data System (ADS)

    Horváth, Zs.; Gergely, L. Á.

    2013-11-01

    Spherically symmetric brane black holes have tidal charge which modifies both weak and strong lensing characteristics. Even if lensing measurements are in agreement with a Schwarzschild lens, the margin of error of the detecting instrument allows for a certain tidal charge only. In this paper we derive the respective constraint on the tidal charge of the supermassive black hole (SMBH) in the center of our galaxy, based on the radius of the first relativistic Einstein ring due to strong lensing. We find that even if general relativistic predictions are confirmed by high precision strong lensing measurements, SMBHs could have a much larger tidal charge than the Sun or neutron stars.

  2. Nuclear physics from lattice QCD at strong coupling.

    PubMed

    de Forcrand, Ph; Fromm, M

    2010-03-19

    We study numerically the strong coupling limit of lattice QCD with one flavor of massless staggered quarks. We determine the complete phase diagram as a function of temperature and chemical potential, including a tricritical point. We clarify the nature of the low temperature dense phase, which is strongly bound "nuclear" matter. This strong binding is explained by the nuclear potential, which we measure. Finally, we determine, from this first-principles limiting case of QCD, the masses of "atomic nuclei" up to A=12 "carbon".

  3. ACCELERATION OF POLARIZED BEAMS USING MULTIPLE STRONG PARTIAL SIBERIAN SNAKES.

    SciTech Connect

    ROSER,T.AHRENS,L.BAI,M.ET AL.

    2004-07-05

    Acceleration of polarized protons in the energy range of 5 to 25 GeV is particularly difficult since depolarizing spin resonances are strong enough to cause significant depolarization but full Siberian snakes cause intolerably large orbit excursions. Using a 20-30% partial Siberian snake both imperfection and intrinsic resonances can be overcome. Such a strong partial Siberian snake was designed for the Brookhaven AGS using a dual pitch helical superconducting dipole. Multiple strong partial snakes are also discussed for spin matching at beam injection and extraction.

  4. ACCELERATION OF POLARIZED BEAMS USING MULTIPLE STRONG PARTIAL SIBERIAN SNAKES.

    SciTech Connect

    ROSER,T.; AHRENS,L.; BAI,M.; COURANT,E.; GLENN,J.W.; GUPTA,R.C.; HUANG,H.; LUCCIO,A.U.; MACKAY,W.W.; TSOUPAS,N.; WILLEN,E.; OKAMURA,M.; TAKANO,J.

    2004-10-10

    Acceleration of polarized protons in the energy range of 5 to 25 GeV is particularly difficult since depolarizing spin resonances are strong enough to cause significant depolarization but full Siberian snakes cause intolerably large orbit excursions. Using a 20-30% partial Siberian snake both imperfection and intrinsic resonances can be overcome. Such a strong partial Siberian snake was designed for the Brookhaven AGS using a dual pitch helical superconducting dipole. Multiple strong partial snakes are also discussed for spin matching at beam injection and extraction.

  5. Strongly enhanced field-dependent single-molecule electroluminescence

    NASA Astrophysics Data System (ADS)

    Lee, Tae-Hee; Gonzalez, Jose I.; Dickson, Robert M.

    2002-08-01

    Individual, strongly electroluminescent Agn molecules (n = 28 atoms) have been electrically written within otherwise nonemissive silver oxide films. Exhibiting characteristic single-molecule behavior, these individual room-temperature molecules exhibit extreme electroluminescence enhancements (>104 vs. bulk and dc excitation on a per molecule basis) when excited with specific ac frequencies. Occurring through field extraction of electrons with subsequent reinjection and radiative recombination, single-molecule electroluminescence is enhanced by a general mechanism that avoids slow bulk material response. Thus, while we detail strong electroluminescence from single, highly fluorescent Agn molecules, this mechanism also yields strong ac-excited electroluminescence from similarly prepared, but otherwise nonemissive, individual Cu nanoclusters.

  6. Some results on the spectra of strongly regular graphs

    NASA Astrophysics Data System (ADS)

    Vieira, Luís António de Almeida; Mano, Vasco Moço

    2016-06-01

    Let G be a strongly regular graph whose adjacency matrix is A. We associate a real finite dimensional Euclidean Jordan algebra 𝒱, of rank three to the strongly regular graph G, spanned by I and the natural powers of A, endowed with the Jordan product of matrices and with the inner product as being the usual trace of matrices. Finally, by the analysis of the binomial Hadamard series of an element of 𝒱, we establish some inequalities on the parameters and on the spectrum of a strongly regular graph like those established in theorems 3 and 4.

  7. Sucralose Destabilization of Protein Structure.

    PubMed

    Chen, Lee; Shukla, Nimesh; Cho, Inha; Cohn, Erin; Taylor, Erika A; Othon, Christina M

    2015-04-16

    Sucralose is a commonly employed artificial sweetener that behaves very differently than its natural disaccharide counterpart, sucrose, in terms of its interaction with biomolecules. The presence of sucralose in solution is found to destabilize the native structure of two model protein systems: the globular protein bovine serum albumin and an enzyme staphylococcal nuclease. The melting temperature of these proteins decreases as a linear function of sucralose concentration. We correlate this destabilization to the increased polarity of the molecule. The strongly polar nature is manifested as a large dielectric friction exerted on the excited-state rotational diffusion of tryptophan using time-resolved fluorescence anisotropy. Tryptophan exhibits rotational diffusion proportional to the measured bulk viscosity for sucrose solutions over a wide range of concentrations, consistent with a Stokes-Einstein model. For sucralose solutions, however, the diffusion is dependent on the concentration, strongly diverging from the viscosity predictions, and results in heterogeneous rotational diffusion.

  8. A novel Arometic compound acts synergistically with a naturally occurring monoterpene to elicit strong behavioral responses in Asian citrus psyllid

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Inscent, Inc. has developed methodologies for rapidly screening potential ligands of chemosensory proteins (CSPs) isolated from the antennae of target insects. These novel ligands, referred to as Arometics, mimic naturally-occurring odorants and may function as super-stimuli because of their strong ...

  9. Conversion of high and low pollen protein diets into protein in worker honey bees (Hymenoptera: Apidae).

    PubMed

    Basualdo, M; Barragán, S; Vanagas, L; García, C; Solana, H; Rodríguez, E; Bedascarrasbure, E

    2013-08-01

    Adequate protein levels are necessary to maintain strong honey bee [Apis mellifera (L.)] colonies. The aim of this study was to quantify how pollens with different crude protein contents influence protein stores within individual honey bees. Caged bees were fed one of three diets, consisting of high-protein-content pollen, low-protein-content pollen, or protein-free diet as control; measurements were made based on protein content in hemolymph and fat body, fat body weight, and body weight. Vitellogenin in hemolymph was also measured. Bees fed with high crude protein diet had significantly higher levels of protein in hemolymph and fat bodies. Caged bees did not increase pollen consumption to compensate for the lower protein in the diet, and ingesting approximately 4 mg of protein per bee could achieve levels of 20 microg/microl protein in hemolymph. Worker bees fed with low crude protein diet took more time in reaching similar protein content of the bees that were fed with high crude protein diet. The data showed that fat bodies and body weight were not efficient methods of measuring the protein status of bees. The determination of total protein or vitellogenin concentration in the hemolymph from 13-d-old bees and protein concentration of fat bodies from 9-d-old bees could be good indicators of nutritional status of honey bees.

  10. Total protein

    MedlinePlus

    ... 2016:chap 215. Read More Agammaglobulinemia Albumin - blood (serum) test Amino acids Antibody Burns Chronic Congenital nephrotic syndrome Fibrinogen blood test Glomerulonephritis Hemoglobin Liver disease Malabsorption Multiple myeloma Polycythemia vera Protein in diet ...

  11. Detergent-solubilized Patched purified from Sf9 cells fails to interact strongly with cognate Hedgehog or Ihog homologs.

    PubMed

    Cleveland, Thomas E; McCabe, Jacqueline M; Leahy, Daniel J

    2014-12-01

    Patched (Ptc) is a twelve-pass transmembrane protein that functions as a receptor for the Hedgehog (Hh) family of morphogens. In addition to Ptc, several accessory proteins including the CDO/Ihog family of co-receptors are necessary for proper Hh signaling. Structures of Hh proteins bound to members of the CDO/Ihog family are known, but the nature of the full Hh receptor complex is not well understood. We have expressed the Drosophila Patched and Mouse Patched-1 proteins in Sf9 cells and find that Sonic Hedgehog will bind to Mouse Patched-1 in isolated Sf9 cell membranes but that purified, detergent-solubilized Ptc proteins do not interact strongly with cognate Hh and CDO/Ihog homologs. These results may reflect a nonnative conformation of detergent-solubilized Ptc or that an additional factor or factors lost during purification are required for high-affinity Ptc binding to Hh.

  12. Synchrotron radiation in strongly coupled conformal field theories

    SciTech Connect

    Athanasiou, Christiana; Chesler, Paul M.; Liu, Hong; Rajagopal, Krishna; Nickel, Dominik

    2010-06-15

    Using gauge/gravity duality, we compute the energy density and angular distribution of the power radiated by a quark undergoing circular motion in strongly coupled N=4 supersymmetric Yang-Mills theory. We compare the strong coupling results to those at weak coupling, finding them to be very similar. In both regimes, the angular distribution of the radiated power is in fact similar to that of synchrotron radiation produced by an electron in circular motion in classical electrodynamics: the quark emits radiation in a narrow beam along its velocity vector with a characteristic opening angle {alpha}{approx}1/{gamma}. To an observer far away from the quark, the emitted radiation appears as a short periodic burst, just like the light from a lighthouse does to a ship at sea. Our strong coupling results are valid for any strongly coupled conformal field theory with a dual classical gravity description.

  13. Strong Magnetic Anomalies on the Lunar Near Side

    NASA Technical Reports Server (NTRS)

    Halekas, J. S.; Mitchell, D. L.; Lin, R. P.; Frey, S.; Acuna, M. H.; Hood, L. L.; Binder, A.

    2000-01-01

    The near side magnetic field is dominated by the demagnetized Imbrium basin and Oceanus Procellarum regions. However, surrounding this area are a number of strong magnetic anomalies, including Rima Sirsalis and Reiner Gamma.

  14. Strong decays of excited baryons in Large Nc QCD

    SciTech Connect

    Goity, Jose; Scoccola, Norberto

    2007-02-01

    We present the analysis of the strong decays widths of excited baryons in the framework of the 1/Nc expansion of QCD. These studies are performed up to order 1/Nc and include both positive and negative parity excited baryons.

  15. Measurement, characterization, and prediction of strong ground motion

    USGS Publications Warehouse

    Joyner, William; Boore, David M.

    1988-01-01

    A number of predictive relationships derived from regression analysis of strong-motion data are available for horizontal peak acceleration, velocity, and response spectral values. Theoretical prediction of ground motion calls for stochastic source models because source heterogeneities control the amplitude of ground motion at most, if not all, frequencies of engineering interest. Theoretical methods have been developed for estimation of ground-motion parameters and simulation of ground-motion time series. These methods are particularly helpful for regions such, as eastern North America where strong-motion data are sparse. The authors survey the field, first reviewing developments in ground-motion measurement and data processing. The authors then consider the choice of parameters for characterizing strong ground motion and describe the wave-types involved in strong ground motion and the factors affecting ground-motion amplitudes. They conclude by describing methods for predicting ground motion.

  16. Strong profiling is not mathematically optimal for discovering rare malfeasors

    SciTech Connect

    Press, William H

    2008-01-01

    In a large population of individuals labeled j = 1,2,...,N, governments attempt to find the rare malfeasor j = j, (terrorist, for example) by making use of priors p{sub j} that estimate the probability of individual j being a malfeasor. Societal resources for secondary random screening such as airport search or police investigation are concentrated against individuals with the largest priors. They may call this 'strong profiling' if the concentration is at least proportional to p{sub j} for the largest values. Strong profiling often results in higher probability, but otherwise innocent, individuals being repeatedly subjected to screening. They show here that, entirely apart from considerations of social policy, strong profiling is not mathematically optimal at finding malfeasors. Even if prior probabilities were accurate, their optimal use would be only as roughly the geometric mean between a strong profiling and a completely uniform sampling of the population.

  17. Physics in Strong Magnetic Fields Near Neutron Stars.

    ERIC Educational Resources Information Center

    Harding, Alice K.

    1991-01-01

    Discussed are the behaviors of particles and energies in the magnetic fields of neutron stars. Different types of possible research using neutron stars as a laboratory for the study of strong magnetic fields are proposed. (CW)

  18. Strong, reversible underwater adhesion via gecko-inspired hydrophobic fibers.

    PubMed

    Soltannia, Babak; Sameoto, Dan

    2014-12-24

    Strong, reversible underwater adhesion using gecko-inspired surfaces is achievable through the use of a hydrophobic structural material and does not require surface modification or suction cup effects for this adhesion to be effective. Increased surface energy can aid in dry adhesion in an air environment but strongly degrades wet adhesion via reduction of interfacial energy underwater. A direct comparison of structurally identical but chemically different mushroom shaped fibers shows that strong, reversible adhesion, even in a fully wetted, stable state, is feasible underwater if the structural material of the fibers is hydrophobic and the mating surface is not strongly hydrophilic. The exact adhesion strength will be a function of the underwater interfacial energy between surfaces and the specific failure modes of individual fibers. This underwater adhesion has been calculated to be potentially greater than the dry adhesion for specific combinations of hydrophobic surfaces.

  19. QCD and strongly coupled gauge theories: challenges and perspectives.

    PubMed

    Brambilla, N; Eidelman, S; Foka, P; Gardner, S; Kronfeld, A S; Alford, M G; Alkofer, R; Butenschoen, M; Cohen, T D; Erdmenger, J; Fabbietti, L; Faber, M; Goity, J L; Ketzer, B; Lin, H W; Llanes-Estrada, F J; Meyer, H B; Pakhlov, P; Pallante, E; Polikarpov, M I; Sazdjian, H; Schmitt, A; Snow, W M; Vairo, A; Vogt, R; Vuorinen, A; Wittig, H; Arnold, P; Christakoglou, P; Di Nezza, P; Fodor, Z; Garcia I Tormo, X; Höllwieser, R; Janik, M A; Kalweit, A; Keane, D; Kiritsis, E; Mischke, A; Mizuk, R; Odyniec, G; Papadodimas, K; Pich, A; Pittau, R; Qiu, J-W; Ricciardi, G; Salgado, C A; Schwenzer, K; Stefanis, N G; von Hippel, G M; Zakharov, V I

    We highlight the progress, current status, and open challenges of QCD-driven physics, in theory and in experiment. We discuss how the strong interaction is intimately connected to a broad sweep of physical problems, in settings ranging from astrophysics and cosmology to strongly coupled, complex systems in particle and condensed-matter physics, as well as to searches for physics beyond the Standard Model. We also discuss how success in describing the strong interaction impacts other fields, and, in turn, how such subjects can impact studies of the strong interaction. In the course of the work we offer a perspective on the many research streams which flow into and out of QCD, as well as a vision for future developments.

  20. Strongly-Interacting Fermi Gases in Reduced Dimensions

    DTIC Science & Technology

    2009-05-29

    effective theories of the strong interactions), astrophysics (compact stellar objects), the physics of quark -gluon plasmas (elliptic flow), and most...strong interactions: Superconductors, neutron stars and quark -gluon plasmas on a desktop," Seminar on Modern Optics and Spectroscopy, M. I. T...interface of quark -gluon plasma physics and cold-atom physics," (Trento, Italy, March 19-23, 2007). Talk given by Andrey Turlapov. 17) J. E. Thomas

  1. Thermoelectric effects in organic conductors in a strong magnetic field

    SciTech Connect

    Kirichenko, O. V.; Peschanskii, V. G. Hasan, R. A.

    2007-07-15

    The linear response of the electron system of a layered conductor to the temperature gradient in this system in a strong magnetic field is investigated theoretically. Thermoelectric emf is studied as a function of the magnitude and orientation of a strong external magnetic field; the experimental investigation of this function, combined with the study of the electric and thermal resistance, allows one to completely determine the structure of the energy spectrum of charge carriers.

  2. Nonlinear Generalized Hydrodynamic Wave Equations in Strongly Coupled Dusty Plasmas

    SciTech Connect

    Veeresha, B. M.; Sen, A.; Kaw, P. K.

    2008-09-07

    A set of nonlinear equations for the study of low frequency waves in a strongly coupled dusty plasma medium is derived using the phenomenological generalized hydrodynamic (GH) model and is used to study the modulational stability of dust acoustic waves to parallel perturbations. Dust compressibility contributions arising from strong Coulomb coupling effects are found to introduce significant modifications in the threshold and range of the instability domain.

  3. Strong WW scattering chiral lagrangians, unitarity and resonances

    SciTech Connect

    Pelaez, J.R.

    1996-08-01

    Chiral lagrangians provide a model independent description of the strongly interacting symmetry breaking sector. In this work, first we review the LHC sensitivity to the chiral parameters (in the hardest case of non-resonant low-energy WW scattering). Later we show how to reproduce or predict the resonance spectrum by means of dispersion theory and the inverse amplitude method. We present a parameter space scan that covers many different strong WW scattering scenarios.

  4. Low-energy structures in strong-field ionization

    NASA Astrophysics Data System (ADS)

    Ivanov, I. A.; Nam, Chang Hee; Kim, Kyung Taec

    2016-04-01

    We show that the Gabor transform provides a convenient tool allowing one to study the origin of the low-energy structures (LES) in the process of the strong-field ionization. The classical trajectories associated with the stationary points of the Gabor transform enable us to explicate the role of the forward scattering process in forming LES. Our approach offers a fully quantum mechanical description of LES, which can also be applied for other strong-field processes.

  5. Line-of-sight structure toward strong lensing galaxy clusters

    SciTech Connect

    Bayliss, Matthew B.; Johnson, Traci; Sharon, Keren; Gladders, Michael D.; Oguri, Masamune

    2014-03-01

    We present an analysis of the line-of-sight structure toward a sample of 10 strong lensing cluster cores. Structure is traced by groups that are identified spectroscopically in the redshift range, 0.1 ≤ z ≤ 0.9, and we measure the projected angular and comoving separations between each group and the primary strong lensing clusters in each corresponding line of sight. From these data we measure the distribution of projected angular separations between the primary strong lensing clusters and uncorrelated large-scale structure as traced by groups. We then compare the observed distribution of angular separations for our strong lensing selected lines of sight against the distribution of groups that is predicted for clusters lying along random lines of sight. There is clear evidence for an excess of structure along the line of sight at small angular separations (θ ≤ 6') along the strong lensing selected lines of sight, indicating that uncorrelated structure is a significant systematic that contributes to producing galaxy clusters with large cross sections for strong lensing. The prevalence of line-of-sight structure is one of several biases in strong lensing clusters that can potentially be folded into cosmological measurements using galaxy cluster samples. These results also have implications for current and future studies—such as the Hubble Space Telescope Frontier Fields—that make use of massive galaxy cluster lenses as precision cosmological telescopes; it is essential that the contribution of line-of-sight structure be carefully accounted for in the strong lens modeling of the cluster lenses.

  6. John Donovan Strong; 50 years in optics: introduction.

    PubMed

    Cook, L F; Sakai, H; Barron, L

    1982-01-15

    In March 1981 the Department of Physics and Astronomy of the University of Massachusetts held a two-day symposium on its Amherst campus to honor John Strong and to mark his retirement at the close of the 1981 academic year after 50 years of optics teaching and research. This introduction briefly reviews the symposium papers (published in this issue) that are a testimony to the respect and affection that the world of optics has for John Donovan Strong.

  7. Signature Tracking for Optimized Nutrition and Training (STRONG)

    DTIC Science & Technology

    2014-08-01

    ii   AFRL-RH-WP-TP-2014-0038 SIGNATURE TRACKING FOR OPTIMIZED NUTRITION AND TRAINING (STRONG) Joshua Hagen Human Signatures Branch...Signature TRacking for Optimized Nutrition and TraininG (STRONG) 5a. CONTRACT NUMBER In-House 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 62202F 6...human performance augmentation led by multiple researchers at AFRL. Research areas include Physical Training, Nutrition /Supplementation, Signatures, and

  8. Mean-field descriptions of collective migration with strong adhesion.

    PubMed

    Johnston, Stuart T; Simpson, Matthew J; Baker, Ruth E

    2012-05-01

    Random walk models based on an exclusion process with contact effects are often used to represent collective migration where individual agents are affected by agent-to-agent adhesion. Traditional mean-field representations of these processes take the form of a nonlinear diffusion equation which, for strong adhesion, does not predict the averaged discrete behavior. We propose an alternative suite of mean-field representations, showing that collective migration with strong adhesion can be accurately represented using a moment closure approach.

  9. Strongly-coupled plasmas formed from laser-heated solids

    PubMed Central

    Lyon, M.; Bergeson, S. D.; Hart, G.; Murillo, M. S.

    2015-01-01

    We present an analysis of ion temperatures in laser-produced plasmas formed from solids with different initial lattice structures. We show that the equilibrium ion temperature is limited by a mismatch between the initial crystallographic configuration and the close-packed configuration of a strongly-coupled plasma, similar to experiments in ultracold neutral plasmas. We propose experiments to demonstrate and exploit this crystallographic heating in order to produce a strongly coupled plasma with a coupling parameter of several hundred. PMID:26503293

  10. Reorganization of hydrogen bond network makes strong polyelectrolyte brushes pH-responsive

    PubMed Central

    Wu, Bo; Wang, Xiaowen; Yang, Jun; Hua, Zan; Tian, Kangzhen; Kou, Ran; Zhang, Jian; Ye, Shuji; Luo, Yi; Craig, Vincent S. J.; Zhang, Guangzhao; Liu, Guangming

    2016-01-01

    Weak polyelectrolytes have found extensive practical applications owing to their rich pH-responsive properties. In contrast, strong polyelectrolytes have long been regarded as pH-insensitive based on the well-established fact that the average degree of charging of strong polyelectrolyte chains is independent of pH. The possible applications of strong polyelectrolytes in smart materials have, thus, been severely limited. However, we demonstrate that almost all important properties of strong polyelectrolyte brushes (SPBs), such as chain conformation, hydration, stiffness, surface wettability, lubricity, adhesion, and protein adsorption are sensitive to pH. The pH response originates from the reorganization of the interchain hydrogen bond network between the grafted chains, triggered by the pH-mediated adsorption-desorption equilibrium of hydronium or hydroxide with the brushes. The reorganization process is firmly identified by advanced sum-frequency generation vibrational spectroscopy. Our findings not only provide a new understanding of the fundamental properties of SPBs but also uncover an extensive family of building blocks for constructing pH-responsive materials. PMID:27532049

  11. Strong-Motion Program report, January-December 1985

    USGS Publications Warehouse

    Porcella, R. L.

    1989-01-01

    This Program Report contains preliminary information on the nature and availability of strong-motion data recorded by the U.S. Geological Survey (USGS). The Strong-Motion Program is operated by the USGS in cooperation with numerous Federal, State, and local agencies and private organizations. Major objective of this program are to record both strong ground motion and the response of various types of engineered structures during earthquakes, and to disseminate this information and data to the international earthquake-engineering research and design community. This volume contains a summary of the accelerograms recovered from the USGS National Strong-Motion Instrumentation Network during 1985, summaries of recent strong-motion publications, notes on the availability of digitized data, and general information related to the USGS and other strong-motion programs. The data summary in table 1 contains information on all USGS accelerograms recovered (though not necessarily recorded) during 1985; event data are taken from "Preliminary Determination of Epicenters," published by the USGS.

  12. Atomic excitation and acceleration in strong laser fields

    NASA Astrophysics Data System (ADS)

    Zimmermann, H.; Eichmann, U.

    2016-10-01

    Atomic excitation in the tunneling regime of a strong-field laser-matter interaction has been recently observed. It is conveniently explained by the concept of frustrated tunneling ionization (FTI), which naturally evolves from the well-established tunneling picture followed by classical dynamics of the electron in the combined laser field and Coulomb field of the ionic core. Important predictions of the FTI model such as the n distribution of Rydberg states after strong-field excitation and the dependence on the laser polarization have been confirmed in experiments. The model also establishes a sound basis to understand strong-field acceleration of neutral atoms in strong laser fields. The experimental observation has become possible recently and initiated a variety of experiments such as atomic acceleration in an intense standing wave and the survival of Rydberg states in strong laser fields. Furthermore, the experimental investigations on strong-field dissociation of molecules, where neutral excited fragments after the Coulomb explosion of simple molecules have been observed, can be explained. In this review, we introduce the subject and give an overview over relevant experiments supplemented by new results.

  13. Membrane tension controls the assembly of curvature-generating proteins

    NASA Astrophysics Data System (ADS)

    Simunovic, Mijo; Voth, Gregory A.

    2015-05-01

    Proteins containing a Bin/Amphiphysin/Rvs (BAR) domain regulate membrane curvature in the cell. Recent simulations have revealed that BAR proteins assemble into linear aggregates, strongly affecting membrane curvature and its in-plane stress profile. Here, we explore the opposite question: do mechanical properties of the membrane impact protein association? By using coarse-grained molecular dynamics simulations, we show that increased surface tension significantly impacts the dynamics of protein assembly. While tensionless membranes promote a rapid formation of long-living linear aggregates of N-BAR proteins, increase in tension alters the geometry of protein association. At high tension, protein interactions are strongly inhibited. Increasing surface density of proteins leads to a wider range of protein association geometries, promoting the formation of meshes, which can be broken apart with membrane tension. Our work indicates that surface tension may play a key role in recruiting proteins to membrane-remodelling sites in the cell.

  14. Recombinant Newcastle Disease virus capsids displaying enterovirus 71 VP1 fragment induce a strong immune response in rabbits.

    PubMed

    Sivasamugham, Lalita Ambigai; Cardosa, Mary Jane; Tan, Wen Siang; Yusoff, Khatijah

    2006-08-01

    The complete VP1 protein of EV71 was truncated into six segments and fused to the C-terminal ends of full-length nucleocapsid protein (NPfl) and truncated NP (NPt; lacks 20% amino acid residues from its C-terminal end) of newcastle disease virus (NDV). Western blot analysis using anti-VP1 rabbit serum showed that the N-terminal region of the VP1 protein contains a major antigenic region. The recombinant proteins carrying the truncated VP1 protein, VP1(1-100), were expressed most efficiently in Escherichia coli as determined by Western blot analysis. Electron microscopic analysis of the purified recombinant protein, NPt-VP(1-100) revealed that it predominantly self-assembled into intact ring-like structures whereas NPfl-VP(1-100) recombinant proteins showed disrupted ring-like formations. Rabbits immunized with the purified NPt-VP(1-100) and NPfl-VP(1-100) exhibited a strong immune response against the complete VP1 protein. The antisera of these recombinant proteins also reacted positively with authentic enterovirus 71 and the closely related Coxsackievirus A16 when analyzed by an immunofluorescence assay suggesting their potential as immunological reagents for the detection of anti-enterovirus 71 antibodies in serum samples.

  15. Calcium transport in strongly calcifying laying birds: mechanisms and regulation.

    PubMed

    Bar, Arie

    2009-04-01

    Birds that lay long clutches (series of eggs laid sequentially before a "pause day"), among them the high-producing, strongly-calcifying Gallus gallus domesticus (domestic hen) and Coturnix coturnix japonica (Japanese quail), transfer about 10% of their total body calcium daily. They appear, therefore, to be the most efficient calcium-transporters among vertebrates. Such intensive transport imposes severe demands on ionic calcium (Ca2+) homeostasis, and activates at least two extremely effective mechanisms for Ca2+ transfer from food and bone to the eggshell. This review focuses on the development, action and regulation of the mechanisms associated with paracellular and transcellular Ca2+ transport in the intestine and the eggshell gland (ESG); it also considers some of the proteins (calbindin, Ca2+ATPase, Na+/Ca2+ exchange, epithelial calcium channels (TRPVs), osteopontin and carbonic anhydrase (CA) associated with this phenomenon. Calbindins are discussed in some detail, as they appear to be a major component of the transcellular transport system, and as only they have been studied extensively in birds. The review aims to gather old and new knowledge, which could form a conceptual basis, albeit not a completely accepted one, for our understanding of the mechanisms associated with this phenomenon. In the intestine, the transcellular pathway appears to compensate for low Ca2+ intake, but in birds fed adequate calcium the major drive for calcium absorption remains the electrochemical potential difference (ECPD) that facilitates paracellular transport. However, the mechanisms involved in Ca2+ transport into the ESG lumen are not yet established. In the ESG, the presence of Ca2+-ATPase and calbindin--two components of the transcellular transport pathway--and the apparently uphill transport of Ca2+ support the idea that Ca2+ is transported via the transcellular pathway. However, the positive (plasma with respect to mucosa) electrical potential difference (EPD) in the

  16. Strong cation exchange chromatography in analysis of posttranslational modifications: innovations and perspectives.

    PubMed

    Edelmann, Mariola J

    2011-01-01

    Strong cation exchange (SCX) chromatography has been utilized as an excellent separation technique that can be combined with reversed-phase (RP) chromatography, which is frequently used in peptide mass spectrometry. Although SCX is valuable as the second component of such two-dimensional separation methods, its application goes far beyond efficient fractionation of complex peptide mixtures. Here I describe how SCX facilitates mapping of the protein posttranslational modifications (PTMs), specifically phosphorylation and N-terminal acetylation. The SCX chromatography has been mainly used for enrichment of these two PTMs, but it might also be beneficial for high-throughput analysis of other modifications that alter the net charge of a peptide.

  17. Separating proteins with activated carbon.

    PubMed

    Stone, Matthew T; Kozlov, Mikhail

    2014-07-15

    Activated carbon is applied to separate proteins based on differences in their size and effective charge. Three guidelines are suggested for the efficient separation of proteins with activated carbon. (1) Activated carbon can be used to efficiently remove smaller proteinaceous impurities from larger proteins. (2) Smaller proteinaceous impurities are most efficiently removed at a solution pH close to the impurity's isoelectric point, where they have a minimal effective charge. (3) The most efficient recovery of a small protein from activated carbon occurs at a solution pH further away from the protein's isoelectric point, where it is strongly charged. Studies measuring the binding capacities of individual polymers and proteins were used to develop these three guidelines, and they were then applied to the separation of several different protein mixtures. The ability of activated carbon to separate proteins was demonstrated to be broadly applicable with three different types of activated carbon by both static treatment and by flowing through a packed column of activated carbon.

  18. Live strong and prosper: the importance of skeletal muscle strength for healthy ageing.

    PubMed

    McLeod, Michael; Breen, Leigh; Hamilton, D Lee; Philp, Andrew

    2016-06-01

    Due to improved health care, diet and infrastructure in developed countries, since 1840 life expectancy has increased by approximately 2 years per decade. Accordingly, by 2050, a quarter of Europe's population will be over 65 years, representing a 10 % rise in half a century. With this rapid rise comes an increased prevalence of diseases of ageing and associated healthcare expenditure. To address the health consequences of global ageing, research in model systems (worms, flies and mice) has indicated that reducing the rate of organ growth, via reductions in protein synthetic rates, has multi-organ health benefits that collectively lead to improvements in lifespan. In contrast, human pre-clinical, clinical and large cohort prospective studies demonstrate that ageing leads to anabolic (i.e. growth) impairments in skeletal muscle, which in turn leads to reductions in muscle mass and strength, factors directly associated with mortality rates in the elderly. As such, increasing muscle protein synthesis via exercise or protein-based nutrition maintains a strong, healthy muscle mass, which in turn leads to improved health, independence and functionality. The aim of this review is to critique current literature relating to the maintenance of muscle mass across lifespan and discuss whether maintaining or reducing protein synthesis is the most logical approach to support musculoskeletal function and by extension healthy human ageing.

  19. Ionization and dissociation dynamics of molecules in strong laser fields

    NASA Astrophysics Data System (ADS)

    Lai, Wei

    The fast advancement of ultrashort-pulsed high-intensity laser technology allows for generating an electric field equivalent to the Coulomb field inside an atom or a molecule (e.g., EC=5.14x109 V/cm at the 1s orbit radius a0=0.0529 nm of the hydrogen atom, which corresponds to an intensity of 3.54x1016 W/cm2). Atoms and molecules exposed in such a field will easily be ionized, as the external field is strong enough to remove the electrons from the core. This is usually referred to "strong field". Strong fields provide a new tool for studying the interaction of atoms and molecules with light in the nonlinear nonperturbative regime. During the past three decades, significant progress has been made in the strong field science. Today, most phenomena involving atoms in strong fields have been relatively well understood by the single-active-electron (SAE) approximation. However, the interpretation of these responses in molecules has encountered great difficulties. Not like atoms that only undergo excitation and ionization, various dissociation channels accompanying excitation and ionization can occur in molecules during the laser pulse interaction, which imparts further complexity to the study of molecules in strong fields. Previous studies have shown that molecules can behave significantly different from rare gas atoms in phenomena as simple as single and double ionization. Molecular dissociation following ionization also presents challenges in strong fields compared to what we have learned in the weak-field regime. This dissertation focuses on experimental studies on ionization and dissociation of some commonly-seen small molecules in strong laser fields. Previous work of molecules in strong fields will be briefly reviewed, particularly on some open questions about multiple dissociation channels, nonsequential double ionization, enhanced ionization and molecular alignment. The identification of various molecular dissociation channels by recent experimental technical

  20. Titanium Alloy Strong Back for IXO Mirror Segments

    NASA Technical Reports Server (NTRS)

    Byron, Glenn P.; Kai-Wang, Chan

    2011-01-01

    A titanium-alloy mirror-holding fixture called a strong back allows the temporary and permanent bonding of a 50 degree D263 glass x-ray mirror (IXO here stands for International X-ray Observatory). The strong back is used to hold and position a mirror segment so that mounting tabs may be bonded to the mirror with ultra-low distortion of the optical surface. Ti-15%Mo alloy was the material of choice for the strong back and tabs because the coefficient of thermal expansion closely matches that of the D263 glass and the material is relatively easy to machine. This invention has the ability to transfer bonded mounting points from a temporary location on the strong back to a permanent location on the strong back with minimal distortion. Secondly, it converts a single mirror segment into a rigid body with an acceptable amount of distortion of the mirror, and then maneuvers that rigid body into optical alignment such that the mirror segment can be bonded into a housing simulator or mirror module. Key problems are that the mirrors are 0.4-mm thick and have a very low coefficient of thermal expansion (CTE). Because the mirrors are so thin, they are very flexible and are easily distorted. When permanently bonding the mirror, the goal is to achieve a less than 1-micron distortion. Temperature deviations in the lab, which have been measured to be around 1 C, have caused significant distortions in the mirror segment.