Science.gov

Sample records for non-conservative aminoacid substitutions

  1. Amino-acid substitution in alpha-spectrin commonly coinherited with nondominant hereditary spherocytosis.

    PubMed

    Tse, W T; Gallagher, P G; Jenkins, P B; Wang, Y; Benoit, L; Speicher, D; Winkelmann, J C; Agre, P; Forget, B G; Marchesi, S L

    1997-03-01

    Nondominant hereditary spherocytosis (ndHS) is a disorder characterized in some patients by severe hemolytic anemia and marked deficiency of erythrocyte spectrin. This report describes the identification of a variant spectrin chain, alpha-spectrin Bughill or alpha(BH), that is associated with this disorder in a number of patients. Tryptic maps of spectrin from affected individuals revealed an acidic shift in isoelectric point of the alphaII domain peptides at 46 kD and 35 kD. A point mutation at codon 970 of the alpha-spectrin gene (GCT-->GAT), that changes the encoded amino acid from an alanine to an aspartic acid, was identified in genomic DNA of affected patients. The alpha(BH) variant was present in 8 patients with ndHS from five different kindreds but was absent in 4 patients from two other kindreds. The 8 ndHS patients with the alpha(BH) variant appeared to be homozygous for the alpha(BH) variant by analysis of peptide maps of limited tryptic digests of erythrocyte spectrin. However, following genomic DNA analysis, only 2 of these patients were true homozygotes, whereas 6 were found to be doubly heterozygous for the alpha(BH) allele and a second, presumably abnormal, alpha-spectrin gene. These results suggest that, in these 6 patients, the second alpha-spectrin allele is in fact associated with one or more genetic defect(s), causing decreased accumulation of alpha-spectrin. The pattern of transmission of the alpha(BH) allele in certain families suggests that the alpha(BH) amino-acid substitution is not itself responsible for ndHS but is more likely a polymorphic variant that, in some but not all cases, is in linkage disequilibrium with another uncharacterized alpha-spectrin gene defect that itself is a cause of ndHS. PMID:9067503

  2. Directed evolution of P-glycoprotein cysteines reveals site-specific, non-conservative substitutions that preserve multidrug resistance.

    PubMed

    Swartz, Douglas J; Mok, Leo; Botta, Sri K; Singh, Anukriti; Altenberg, Guillermo A; Urbatsch, Ina L

    2014-01-01

    Pgp (P-glycoprotein) is a prototype ABC (ATP-binding-cassette) transporter involved in multidrug resistance of cancer. We used directed evolution to replace six cytoplasmic Cys (cysteine) residues in Pgp with all 20 standard amino acids and selected for active mutants. From a pool of 75000 transformants for each block of three Cys, we identified multiple mutants that preserved drug resistance and yeast mating activity. The most frequent substitutions were glycine and serine for Cys427 (24 and 20%, respectively) and Cys1070 (37 and 25%) of the Walker A motifs in the NBDs (nucleotide-binding domains), Cys1223 in NBD2 (25 and 8%) and Cys638 in the linker region (24 and 16%), whereas close-by Cys669 tolerated glycine (16%) and alanine (14%), but not serine (absent). Cys1121 in NBD2 showed a clear preference for positively charged arginine (38%) suggesting a salt bridge with Glu269 in the ICL2 (intracellular loop 2) may stabilize domain interactions. In contrast, three Cys residues in transmembrane α-helices could be successfully replaced by alanine. The resulting CL (Cys-less) Pgp was fully active in yeast cells, and purified proteins displayed drug-stimulated ATPase activities indistinguishable from WT (wild-type) Pgp. Overall, directed evolution identified site-specific, non-conservative Cys substitutions that allowed building of a robust CL Pgp, an invaluable new tool for future functional and structural studies, and that may guide the construction of other CL proteins where alanine and serine have proven unsuccessful. PMID:24825346

  3. Computer-assisted automated synthesis. III. Synthesis of substituted N-(carboxyalkyl) amino-acid tert-butyl ester derivatives.

    PubMed

    Hayashi, N; Sugawara, T; Kato, S

    1991-01-01

    A versatile automated synthesis apparatus, equipped with a chemical artificial intelligence, was developed to prepare and isolate a wide variety of compounds. The apparatus was to the synthesis of substituted N-(carboxyalkyl)amino-acids. The apparatus [1,2] is composed of units for performing various tasks,for example reagent supply, reaction, purification and separation, each linked to a control system. All synthetic processes, including washing and drying of the apparatus after each synthetic run, were automatically performed from the mixing of the reactants to the isolation of the products as powders or crystals. The reaction of an amino-acid tertbutyl ester acetic acid salt with a 2-keto acid sodium salt produces an unstable intermediate, Schiff base, which is reduced with sodum cyanoborohydride to give a substituted N-(carboxyalkyl)aminoacid tert-butyl ester sodium salt. The equilibrium and the consecutive reactions were controlled by adding sodium cyanoborohydride using the artificial intelligence software, which contained novel kinetic equations [3] and substituent effects [4].Substitued N-(carboxyalkyl)amino-acid tert-butyl esters, 90 derivatives, were automatically synthesized using the computerassisted automated synthesis apparatus. The syntheses were performed unattended 24 hours a day, except for supplying the raw materials, reagents and solvents. The apparatus is extremely valuable for synthesizing many derivatives of a particular compound. The configurations of the products were determined by circular dichroism measurements. PMID:18924904

  4. Computer-assisted automated synthesis. III. Synthesis of substituted N-(carboxyalkyl) amino-acid tert-butyl ester derivatives

    PubMed Central

    Hayashi, Nobuyoshi; Sugawara, Tohru; Kato, Shinji

    1991-01-01

    A versatile automated synthesis apparatus, equipped with a chemical artificial intelligence, was developed to prepare and isolate a wide variety of compounds. The apparatus was to the synthesis of substituted N-(carboxyalkyl)amino-acids. The apparatus [1,2] is composed of units for performing various tasks,for example reagent supply, reaction, purification and separation, each linked to a control system. All synthetic processes, including washing and drying of the apparatus after each synthetic run, were automatically performed from the mixing of the reactants to the isolation of the products as powders or crystals. The reaction of an amino-acid tertbutyl ester acetic acid salt with a 2-keto acid sodium salt produces an unstable intermediate, Schiff base, which is reduced with sodum cyanoborohydride to give a substituted N-(carboxyalkyl)aminoacid tert-butyl ester sodium salt. The equilibrium and the consecutive reactions were controlled by adding sodium cyanoborohydride using the artificial intelligence software, which contained novel kinetic equations [3] and substituent effects [4]. Substitued N-(carboxyalkyl)amino-acid tert-butyl esters, 90 derivatives, were automatically synthesized using the computerassisted automated synthesis apparatus. The syntheses were performed unattended 24 hours a day, except for supplying the raw materials, reagents and solvents. The apparatus is extremely valuable for synthesizing many derivatives of a particular compound. The configurations of the products were determined by circular dichroism measurements. PMID:18924904

  5. Assignment strategy for fast relaxing signals: complete aminoacid identification in thulium substituted calbindin D 9K.

    PubMed

    Balayssac, Stéphane; Jiménez, Beatriz; Piccioli, Mario

    2006-02-01

    Paramagnetic proteins generally contain regions with diverse relaxation properties. Nuclei in regions far from the metal center may behave like those in diamagnetic proteins, but those closer to the metal experience rapid relaxation with accompanying line broadening. We have used a set of NMR experiments optimized to capture data from these various concentric regions in assigning the signals from a paramagnetic Calbindin D 9K derivative in which one of the two calcium ions has been replaced by thulium(III). Normal double- and triple-resonance experiments with 1H detection were used in collecting data from nuclei in the diamagnetic-like region; these approaches identified signals from fewer than 50% of the amino acid residues (those with d > 17.5 A from thulium(III)). Paramagnetism-optimized two-dimensional NMR experiments with 1H detection were used in collecting data from nuclei in the next nearer region (d > 15 A). Standard (d > 14 A) and optimized (d > 9 A) 13C direct-detection experiments were used to capture data from nuclei in the next layer. Finally nuclei closest to the metal were detected by one-dimensional 13C (d > 5 A) and one-dimensional 15N data collection (d > 4.2 A). NMR signals were assigned on the basis of through-bond correlations and, for signals closest to the metal, pseudocontact shifts. The latter were determined from chemical shift differences between assigned signals in thulium(III) and lanthanum(III) derivatives of Calbindin D 9K and they were interpreted on the basis of a structural model for the lanthanide-substituted protein. This approach yielded assignments of at least one resonance per amino acid residue, including those in the thulium(III) coordination sphere. PMID:16518694

  6. Structural and Functional Characteristics of Oxysterol 7α-Hydroxylase with Amino-Acid Substitution R486C and Their Relation to the Appearance of Neurodegenerative Diseases

    NASA Astrophysics Data System (ADS)

    Dichenko, Ya. V.; Yantsevich, A. V.; Usanov, S. A.

    2015-03-01

    The influence of the amino-acid substitution Arg486Cys on the conformational stability of recombinant cytochrome P450 7B1 (CYP7B1, oxysterol 7α-hydroxylase) was studied. The single base change was shown to decrease the free energy of the transition of the heme-protein from its native state to a denatured one, which pointed to a lower thermodynamic stability for the mutant form of the enzyme. This could be the cause of the metabolic disruption of neurosteroids and, as a consequence, the appearance of neurodegenerative diseases.

  7. LASER BIOLOGY AND MEDICINE: Application of laser fluorimetry for determining the influence of a single amino-acid substitution on the individual photophysical parameters of a fluorescent form of a fluorescent protein mRFP1

    NASA Astrophysics Data System (ADS)

    Banishev, A. A.; Vrzheshch, E. P.; Shirshin, E. A.

    2009-03-01

    Individual photophysical parameters of the chromophore of a fluorescent protein mRFP1 and its two mutants (amino-acid substitution at position 66 - mRFP1/ Q66C and mRFP1/Q66S proteins) are determined. For this purpose, apart from conventional methods of fluorimetry and spectrophotometry, nonlinear laser fluorimetry is used. It is shown that the individual extinction coefficients of the chromophore of proteins correlate (correlation coefficient above 0.9) with the volume of the substituted amino-acid residue at position 66 (similar to the positions of the absorption, fluorescence excitation and emission maxima).

  8. A Single Amino-Acid Substitution in the Sodium Transporter HKT1 Associated with Plant Salt Tolerance.

    PubMed

    Ali, Akhtar; Raddatz, Natalia; Aman, Rashid; Kim, Songmi; Park, Hyeong Cheol; Jan, Masood; Baek, Dongwon; Khan, Irfan Ullah; Oh, Dong-Ha; Lee, Sang Yeol; Bressan, Ray A; Lee, Keun Woo; Maggio, Albino; Pardo, Jose M; Bohnert, Hans J; Yun, Dae-Jin

    2016-07-01

    A crucial prerequisite for plant growth and survival is the maintenance of potassium uptake, especially when high sodium surrounds the root zone. The Arabidopsis HIGH-AFFINITY K(+) TRANSPORTER1 (HKT1), and its homologs in other salt-sensitive dicots, contributes to salinity tolerance by removing Na(+) from the transpiration stream. However, TsHKT1;2, one of three HKT1 copies in Thellungiella salsuginea, a halophytic Arabidopsis relative, acts as a K(+) transporter in the presence of Na(+) in yeast (Saccharomyces cerevisiae). Amino-acid sequence comparisons indicated differences between TsHKT1;2 and most other published HKT1 sequences with respect to an Asp residue (D207) in the second pore-loop domain. Two additional T salsuginea and most other HKT1 sequences contain Asn (n) in this position. Wild-type TsHKT1;2 and altered AtHKT1 (AtHKT1(N-D)) complemented K(+)-uptake deficiency of yeast cells. Mutant hkt1-1 plants complemented with both AtHKT1(N) (-) (D) and TsHKT1;2 showed higher tolerance to salt stress than lines complemented by the wild-type AtHKT1 Electrophysiological analysis in Xenopus laevis oocytes confirmed the functional properties of these transporters and the differential selectivity for Na(+) and K(+) based on the n/d variance in the pore region. This change also dictated inward-rectification for Na(+) transport. Thus, the introduction of Asp, replacing Asn, in HKT1-type transporters established altered cation selectivity and uptake dynamics. We describe one way, based on a single change in a crucial protein that enabled some crucifer species to acquire improved salt tolerance, which over evolutionary time may have resulted in further changes that ultimately facilitated colonization of saline habitats. PMID:27208305

  9. A Single Amino-Acid Substitution in the Sodium Transporter HKT1 Associated with Plant Salt Tolerance1[OPEN

    PubMed Central

    Ali, Akhtar; Aman, Rashid; Park, Hyeong Cheol; Jan, Masood; Baek, Dongwon; Khan, Irfan Ullah; Oh, Dong-Ha; Lee, Sang Yeol; Bressan, Ray A.; Lee, Keun Woo; Maggio, Albino; Yun, Dae-Jin

    2016-01-01

    A crucial prerequisite for plant growth and survival is the maintenance of potassium uptake, especially when high sodium surrounds the root zone. The Arabidopsis HIGH-AFFINITY K+ TRANSPORTER1 (HKT1), and its homologs in other salt-sensitive dicots, contributes to salinity tolerance by removing Na+ from the transpiration stream. However, TsHKT1;2, one of three HKT1 copies in Thellungiella salsuginea, a halophytic Arabidopsis relative, acts as a K+ transporter in the presence of Na+ in yeast (Saccharomyces cerevisiae). Amino-acid sequence comparisons indicated differences between TsHKT1;2 and most other published HKT1 sequences with respect to an Asp residue (D207) in the second pore-loop domain. Two additional T. salsuginea and most other HKT1 sequences contain Asn (n) in this position. Wild-type TsHKT1;2 and altered AtHKT1 (AtHKT1N-D) complemented K+-uptake deficiency of yeast cells. Mutant hkt1-1 plants complemented with both AtHKT1N-D and TsHKT1;2 showed higher tolerance to salt stress than lines complemented by the wild-type AtHKT1. Electrophysiological analysis in Xenopus laevis oocytes confirmed the functional properties of these transporters and the differential selectivity for Na+ and K+ based on the n/d variance in the pore region. This change also dictated inward-rectification for Na+ transport. Thus, the introduction of Asp, replacing Asn, in HKT1-type transporters established altered cation selectivity and uptake dynamics. We describe one way, based on a single change in a crucial protein that enabled some crucifer species to acquire improved salt tolerance, which over evolutionary time may have resulted in further changes that ultimately facilitated colonization of saline habitats. PMID:27208305

  10. A single amino-acid substitution toggles chloride dependence of the alpha-amylase paralog amyrel in Drosophila melanogaster and Drosophila virilis species.

    PubMed

    Claisse, Gaëlle; Feller, Georges; Bonneau, Magalie; Da Lage, Jean-Luc

    2016-08-01

    In animals, most α-amylases are chloride-dependent enzymes. A chloride ion is required for allosteric activation and is coordinated by one asparagine and two arginine side chains. Whereas the asparagine and one arginine are strictly conserved, the main chloride binding arginine is replaced by a glutamine in some rare instances, resulting in the loss of chloride binding and activation. Amyrel is a distant paralogue of α-amylase in Diptera, which was not characterized biochemically to date. Amyrel shows both substitutions depending on the species. In Drosophila melanogaster, an arginine is present in the sequence but in Drosophila virilis, a glutamine occurs at this position. We have investigated basic enzymological parameters and the dependence to chloride of Amyrel of both species, produced in yeast, and in mutants substituting arginine to glutamine or glutamine to arginine. We found that the amylolytic activity of Amyrel is about thirty times weaker than the classical Drosophila α-amylase, and that the substitution of the arginine by a glutamine in D. melanogaster suppressed the chloride-dependence but was detrimental to activity. In contrast, changing the glutamine into an arginine rendered D. virilis Amyrel chloride-dependent, and interestingly, significantly increased its catalytic efficiency. These results show that the chloride ion is not mandatory for Amyrel but stimulates the reaction rate. The possible phylogenetic origin of the arginine/glutamine substitution is also discussed. PMID:27312592

  11. Non-conservative mass transfers in Algols

    NASA Astrophysics Data System (ADS)

    Erdem, A.; Öztürk, O.

    2014-06-01

    We applied a revised model for non-conservative mass transfer in semi-detached binaries to 18 Algol-type binaries showing orbital period increase or decrease in their parabolic O-C diagrams. The combined effect of mass transfer and magnetic braking due to stellar wind was considered when interpreting the orbital period changes of these 18 Algols. Mass transfer was found to be the dominant mechanism for the increase in orbital period of 10 Algols (AM Aur, RX Cas, DK Peg, RV Per, WX Sgr, RZ Sct, BS Sct, W Ser, BD Vir, XZ Vul) while magnetic braking appears to be the responsible mechanism for the decrease in that of 8 Algols (FK Aql, S Cnc, RU Cnc, TU Cnc, SX Cas, TW Cas, V548 Cyg, RY Gem). The peculiar behaviour of orbital period changes in three W Ser-type binary systems (W Ser, itself a prototype, RX Cas and SX Cas) is discussed. The empirical linear relation between orbital period (P) and its rate of change (dP/dt) was also revised.

  12. Amino-Acid Sequence of Porcine Pepsin

    PubMed Central

    Tang, J.; Sepulveda, P.; Marciniszyn, J.; Chen, K. C. S.; Huang, W-Y.; Tao, N.; Liu, D.; Lanier, J. P.

    1973-01-01

    As the culmination of several years of experiments, we propose a complete amino-acid sequence for porcine pepsin, an enzyme containing 327 amino-acid residues in a single polypeptide chain. In the sequence determination, the enzyme was treated with cyanogen bromide. Five resulting fragments were purified. The amino-acid sequence of four of the fragments accounted for 290 residues. Because the structure of a 37-residue carboxyl-terminal fragment was already known, it was not studied. The alignment of these fragments was determined from the sequence of methionyl-peptides we had previously reported. We also discovered the locations of activesite aspartyl residues, as well as the pairing of the three disulfide bridges. A minor component of commercial crystalline pepsin was found to contain two extra amino-acid residues, Ala-Leu-, at the amino-terminus of the molecule. This minor component was apparently derived from a different site of cleavage during the activation of porcine pepsinogen. PMID:4587252

  13. Amino-acid contamination of aqueous hydrochloric acid.

    NASA Technical Reports Server (NTRS)

    Wolman, Y.; Miller, S. L.

    1971-01-01

    Considerable amino-acid contamination in commercially available analytical grade hydrochloric acid (37% HCl) was found. One bottle contained 8,300 nmol of amino-acids per liter. A bottle from another supplier contained 6,700 nmol per liter. The contaminants were mostly protein amino-acids and several unknowns. Data on the volatility of the amino-acids during HCl distillation were also obtained.

  14. Radiation reaction as a non-conservative force

    NASA Astrophysics Data System (ADS)

    Aashish, Sandeep; Haque, Asrarul

    2016-09-01

    We study a system of a finite size charged particle interacting with a radiation field by exploiting Hamilton’s principle for a non-conservative system recently introduced by Galley [1]. This formulation leads to the equation of motion of the charged particle that turns out to be the same as that obtained by Jackson [2]. We show that the radiation reaction stems from the non-conservative part of the effective action for a charged particle. We notice that a charge interacting with a radiation field modeled as a heat bath affords a way to justify that the radiation reaction is a non-conservative force. The topic is suitable for graduate courses on advanced electrodynamics and classical theory of fields.

  15. Stability of massless non-conservative elastic systems

    NASA Astrophysics Data System (ADS)

    Ingerle, Kurt

    2013-09-01

    The critical forces of massless conservative systems can be calculated using equilibrium conditions on the deformed systems. However, if non-trivial equilibrium conditions are absent (e.g., Beck's and Ziegler's column), then the equilibrium method is not applicable. Therefore, these systems were supplied with mass and calculations were performed dynamically. This manuscript demonstrates that the static stability of massless non-conservative systems can be calculated using the energetic stability criterion.

  16. Helicity non-conserving form factor of the proton

    SciTech Connect

    Voutier, E.; Furget, C.; Knox, S.

    1994-04-01

    The study of the hadron structure in the high Q{sup 2} range contributes to the understanding of the mechanisms responsible for the confinement of quarks and gluons. Among the numerous experimental candidates sensitive to these mechanisms, the helicity non-conserving form factor of the proton is a privileged observable since it is controlled by non-perturbative effects. The authors investigate here the feasibility of high Q{sup 2} measurements of this form factor by means of the recoil polarization method in the context of the CEBAF 8 GeV facility. For that purpose, they discuss the development of a high energy proton polarimeter, based on the H({rvec p},pp) elastic scattering, to be placed at the focal plane of a new hadron spectrometer. It is shown that this experimental method significantly improves the knowledge of the helicity non-conserving form factor of the proton up to 10 GeV{sup 2}/c{sup 2}.

  17. Generalized Helmholtz Conditions for Non-Conservative Lagrangian Systems

    NASA Astrophysics Data System (ADS)

    Bucataru, Ioan; Constantinescu, Oana

    2015-12-01

    In this paper we provide generalized Helmholtz conditions, in terms of a semi-basic 1-form, which characterize when a given system of second order ordinary differential equations is equivalent to the Lagrange equations, for some given arbitrary non-conservative forces. For the particular cases of dissipative or gyroscopic forces, these conditions, when expressed in terms of a multiplier matrix, reduce to those obtained in Mestdag et al. (Differential Geom. Appl. 29(1), 55-72, 2011). When the involved geometric structures are homogeneous with respect to the fibre coordinates, we show how one can further simplify the generalized Helmholtz conditions. We provide examples where the proposed generalized Helmholtz conditions, expressed in terms of a semi-basic 1-form, can be integrated and the corresponding Lagrangian and Lagrange equations can be found.

  18. Non-conservative perturbations of homoclinic snaking scenarios

    NASA Astrophysics Data System (ADS)

    Knobloch, Jürgen; Vielitz, Martin

    2016-01-01

    Homoclinic snaking refers to the continuation of homoclinic orbits to an equilibrium E near a heteroclinic cycle connecting E and a periodic orbit P. Typically homoclinic snaking appears in one-parameter families of reversible, conservative systems. Here we discuss perturbations of this scenario which are both non-reversible and non-conservative. We treat this problem analytically in the spirit of the work [3]. The continuation of homoclinic orbits happens with respect to both the original continuation parameter μ and the perturbation parameter λ. The continuation curves are parametrised by the dwelling time L of the homoclinic orbit near P. It turns out that λ (L) tends to zero while the μ vs. L diagram displays isolas or criss-cross snaking curves in a neighbourhood of the original snakes-and-ladder structure. In the course of our studies we adapt both Fenichel coordinates near P and the analysis of Shilnikov problems near P to the present situation.

  19. Plasma amino-acid patterns in liver disease.

    PubMed Central

    Morgan, M Y; Marshall, A W; Milsom, J P; Sherlock, S

    1982-01-01

    Plasma amino-acid concentrations were measured in 167 patients with liver disease of varying aetiology and severity, all free of encephalopathy, and the results compared with those in 57 control subjects matched for age and sex. In the four groups of patients with chronic liver disease (26 patients with chronic active hepatitis, 23 with primary biliary cirrhosis, 11 with cryptogenic cirrhosis, and 48 with alcoholic hepatitis +/- cirrhosis) plasma concentrations of methionine were significantly increased, while concentrations of the three branched chain amino-acids were significantly reduced. In the first three groups of patients plasma concentrations of aspartate, serine, and one or both of the aromatic amino-acids tyrosine and phenylalanine were also significantly increased, while in the patients with alcoholic hepatitis +/- cirrhosis plasma concentrations of glycine, alanine, and phenylalanine were significantly reduced. In the three groups of patients with minimal, potentially reversible liver disease (31 patients with alcoholic fatty liver, 10 with viral hepatitis, and 18 with biliary disease) plasma concentrations of proline and the three branched chain amino-acids were significantly reduced. Patients with alcoholic fatty liver also showed significantly reduced plasma phenylalanine values. Most changes in plasma amino-acid concentrations in patients with chronic liver disease may be explained on the basis of impaired hepatic function, portal-systemic shunting of blood, and hyperinsulinaemia and hyperglucagonaemia. The changes in patients with minimal liver disease are less easily explained. PMID:7076013

  20. The chlorinating behaviour of WCl₆ towards α-aminoacids.

    PubMed

    Bortoluzzi, Marco; Marchetti, Fabio; Murrali, Maria Grazia; Pampaloni, Guido; Zacchini, Stefano

    2015-05-14

    Cl/O interchange took place when WCl6 was allowed to interact with a series of α-aminoacids. The α-ammonium-acylchloride salts [NH2(CH2)3CHC(O)Cl][WOCl5], 1a, and [MeNH2CH2C(O)Cl][WOCl5], 1b, were afforded in ca. 55% yields from the reactions of WCl6 with, respectively, L-proline and sarcosine in CH2Cl2. By using other reaction media (hexane or CHCl3), the α-amino-acylchloride complexes WOCl4[O=C(Cl)CH(CH2)3NH2], 5a, and WOCl4[O=C(Cl)CH(R)NHR'] (R = H, R' = Me, 5b; R = R' = H, 5c; R = Me, R' = H, 5d) were isolated in moderate to good yields from WCl6 and, respectively, L-proline, sarcosine, glycine and L-alanine. The formation of 5a,b is basically the result of HCl release from the parent compounds 1a,b. 5a represents a key intermediate in the course of the reaction leading to (WOCl4)2[μ:κ(2)(O)-dkp], 2, dkp = (S,S)-octahydrodipyrrolo[1,2-a:1',2'-d]pyrazine-5,10-dione. 2 was optimally prepared from WCl6/L-proline under high temperature conditions. Hydrolytic treatment of 2 afforded the L-proline-derived 2,5-diketopiperazine (dkp), which was finally isolated with an overall yield of 70%. 1a,b were characterized by X-ray diffractometry, thus providing very rare examples of crystallographically characterized acylchloride derivatives of α-aminoacids. DFT calculations were extensively carried out in order to shed light on structural and mechanistic features. PMID:25858790

  1. An uncertainty inclusive un-mixing model to identify tracer non-conservativeness

    NASA Astrophysics Data System (ADS)

    Sherriff, Sophie; Rowan, John; Franks, Stewart; Fenton, Owen; Jordan, Phil; hUallacháin, Daire Ó.

    2015-04-01

    Sediment fingerprinting is being increasingly recognised as an essential tool for catchment soil and water management. Selected physico-chemical properties (tracers) of soils and river sediments are used in a statistically-based 'un-mixing' model to apportion sediment delivered to the catchment outlet (target) to its upstream sediment sources. Development of uncertainty-inclusive approaches, taking into account uncertainties in the sampling, measurement and statistical un-mixing, are improving the robustness of results. However, methodological challenges remain including issues of particle size and organic matter selectivity and non-conservative behaviour of tracers - relating to biogeochemical transformations along the transport pathway. This study builds on our earlier uncertainty-inclusive approach (FR2000) to detect and assess the impact of tracer non-conservativeness using synthetic data before applying these lessons to new field data from Ireland. Un-mixing was conducted on 'pristine' and 'corrupted' synthetic datasets containing three to fifty tracers (in the corrupted dataset one target tracer value was manually corrupted to replicate non-conservative behaviour). Additionally, a smaller corrupted dataset was un-mixed using a permutation version of the algorithm. Field data was collected in an 11 km2 river catchment in Ireland. Source samples were collected from topsoils, subsoils, channel banks, open field drains, damaged road verges and farm tracks. Target samples were collected using time integrated suspended sediment samplers at the catchment outlet at 6-12 week intervals from July 2012 to June 2013. Samples were dried (<40°C), sieved (125 µm) and analysed for mineral magnetic susceptibility, anhysteretic remanence and iso-thermal remanence, and geochemical elements Cd, Co, Cr, Cu, Mn, Ni, Pb and Zn (following microwave-assisted acid digestion). Discriminant analysis was used to reduce the number of tracer numbers before un-mixing. Tracer non-conservativeness

  2. Review on hydroxylamine, a precursor to amino-acids

    NASA Astrophysics Data System (ADS)

    Lemaire, Jean Louis

    2015-08-01

    Does life on earth come from interstellar space (IS)?It has been recently demonstrated that part of the terrestrial water is of IS origin [Cleeves et al. Science 2014]. This raises the question whether materials like amino-acids or their pre-biotic molecular precursors could have been formed and brought to earth in the same way than water. Another question is whether these molecules were formed in the gas phase or through reactions on the surface/volume of ice-covered grains. This may then have occurred in the vicinity of proto-stellar cores or deep into a pristine dense molecular clouds at very low temperatures.As far as bio-related molecules are concerned, chemistry with nitrogen-bearing molecules (like NH3 and NO) is involved. I review recent experimental work showing that hydroxylamine (NH2OH) could be formed either by surface or by volume reactions in conditions close to those prevailing in dense media. They use either electron-UV irradiation of water-ammonia ices [Zheng & Kaiser JCPA 2010] or successive hydrogenation of solid nitric oxide[Congiu, Fedoseev & al. ApJL.2012] or the simple oxidation of ammonia [He, Vidali, Lemaire & Garrod, ApJ, 2015] or the reaction of ammonia with hydroxyl radicals in a rare gas matrix [Zins & Krim, 2014, 69th ISMS]. A step further, the synthesis of the simplest amino-acids, glycine (NH2CH2COOH) and L- or D-alanine (NH2CH3CHCOOH) has already been obtained via reactions in the gas phase involving NH2OH+ [Blagojevic & al. MNRAS 2003].In addition to several earlier models demonstrating that the formation of all these molecules is possible in the gas phase, a new recent three-phase gas-grain chemical kinetics model of hot cores [Garrod ApJ 2013] shows that the results of ammonia oxidation we obtain are plausible by surface/volume reactions.Although none of the aforementioned molecules (except glycine in a sample of cometary origin) has been yet detected in the IS, they all are considered by many observers and modelers as likely

  3. Family number non-conservation induced by the supersymmetric mixing of scalar leptons

    SciTech Connect

    Levine, M.J.S.

    1987-08-01

    The most egregious aspect of (N = 1) supersymmetric theories is that each particle state is accompanied by a 'super-partner', a state with identical quantum numbers save that it differs in spin by one half unit. For the leptons these are scalars and are called ''sleptons'', or scalar leptons. These consist of the charged sleptons (selectron, smuon, stau) and the scalar neutrinos ('sneutrinos'). We examine a model of supersymmetry with soft breaking terms in the electroweak sector. Explicit mixing among the scalar leptons results in a number of effects, principally non-conservation of lepton family number. Comparison with experiment permits us to place constraints upon the model. 49 refs., 12 figs.

  4. Vortex motion of dust particles due to non-conservative ion drag force in a plasma

    NASA Astrophysics Data System (ADS)

    Chai, Kil-Byoung; Bellan, Paul M.

    2016-02-01

    Vortex motion of the dust in a dusty plasma is shown to result because non-parallelism of the ion density gradient and the gradient of the magnitude of the ion ambipolar velocity cause the ion drag force on dust grains to be non-conservative. Dust grain poloidal vortices consistent with the model predictions are experimentally observed, and the vortices change character with imposed changes in the ion temperature profile as predicted. For a certain ion temperature profile, two adjacent co-rotating poloidal vortices have a well-defined X-point analogous to the X-point in magnetic reconnection.

  5. Spectroscopy with Laser-cooled Francium and Progress on Atomic Parity Non-conservation

    NASA Astrophysics Data System (ADS)

    Zhang, Jiehang

    Francium, the heaviest alkali, possesses a unique combination of structural simplicity and great sensitivity to effects such as atomic parity non-conservation (APNC). We report in this thesis our progress towards measuring weak-interaction physics in a low energy system: the francium atom. We have built a new generation of high-efficiency laser cooling and trapping facility at TRIUMF national laboratory in Canada. We constructed a precision science chamber and demonstrate francium atom transfer into the precision trap, where the electromagnetic field environments can be exquisitely controlled such that weak-interaction studies via optical and microwave excitations can take place. We perform laser spectroscopy measurements of the hyperfine structure and isotope shifts in a chain of francium isotopes near the neutron closed shell (N = 126), including both ground and isomeric nuclear states. These measurements provide a basis for benchmarking state of the art atomic theory, as well as future nuclear structure calculations in Fr, necessary for interpreting the weak-interaction studies. These developments lay important foundations for precision parity non-conservation measurements with francium.

  6. Evolution of wealth in a non-conservative economy driven by local Nash equilibria

    PubMed Central

    Degond, Pierre; Liu, Jian-Guo; Ringhofer, Christian

    2014-01-01

    We develop a model for the evolution of wealth in a non-conservative economic environment, extending a theory developed in Degond et al. (2014 J. Stat. Phys. 154, 751–780 (doi:10.1007/s10955-013-0888-4)). The model considers a system of rational agents interacting in a game-theoretical framework. This evolution drives the dynamics of the agents in both wealth and economic configuration variables. The cost function is chosen to represent a risk-averse strategy of each agent. That is, the agent is more likely to interact with the market, the more predictable the market, and therefore the smaller its individual risk. This yields a kinetic equation for an effective single particle agent density with a Nash equilibrium serving as the local thermodynamic equilibrium. We consider a regime of scale separation where the large-scale dynamics is given by a hydrodynamic closure with this local equilibrium. A class of generalized collision invariants is developed to overcome the difficulty of the non-conservative property in the hydrodynamic closure derivation of the large-scale dynamics for the evolution of wealth distribution. The result is a system of gas dynamics-type equations for the density and average wealth of the agents on large scales. We recover the inverse Gamma distribution, which has been previously considered in the literature, as a local equilibrium for particular choices of the cost function. PMID:25288808

  7. The amino-acid sequence of kangaroo pancreatic ribonuclease.

    PubMed

    Gaastra, W; Welling, G W; Beintema, J J

    1978-05-01

    Red kangaroo (Macropus rufus) ribonuclease was isolated from pancreatic tissue by affinity chromatography. The amino acid sequence was determined by automatic sequencing of overlapping large fragments and by analysis of shorter peptides obtained by digestion with a number of proteolytic enzymes. The polypeptide chain consists of 122 amino acid residues. Compared to other ribonucleases, the N-terminal residue and residue 114 are deleted. In other pancreatic ribonucleases position 114 is occupied by a cis proline residue in an external loop at the surface of the molecule. Other remarkable substitutions are the presence of a tyrosine residue at position 123 instead of a serine which forms a hydrogen bond with the pyrimidine ring of a nucleotide substrate, and a number of hydrophobichydrophilic interchanges in the sequence 51-55, which forms part of an alpha-helix in bovine ribonuclease and exhibits few substitutions in the placental mammals. Kangaroo ribonuclease contains no carbohydrate, although the enzyme possesses a recognition site for carbohydrate attachment in the sequence Asn-Val-Thr (62-64). The enzyme differs at about 35-40% of the positions from all other mammalian pancreatic ribonucleases sequenced to date, which is in agreement with the early divergence between the marsupials and the placental mammals. From fragmentary data a tentative sequence of red-necked wallaby (Macropus rufogriseus) pancreatic ribonuclease has been derived. Eight differences with the kangaroo sequence were found. PMID:658039

  8. The FrPNC experiment at TRIUMF: Atomic parity non-conservation in francium

    NASA Astrophysics Data System (ADS)

    Aubin, S.; Gomez, E.; Behr, J. A.; Pearson, M. R.; Sheng, D.; Zhang, J.; Collister, R.; Melconian, D.; Flambaum, V. V.; Sprouse, G. D.; Orozco, L. A.; Gwinner, G.

    2012-09-01

    The FrPNC collaboration has begun the construction of an on-line laser cooling and trapping apparatus at TRIUMF to measure atomic parity non-conservation (PNC) and the nuclear anapole moment in a string of artificially produced francium isotopes. Atomic PNC experiments provide unique high precision tests of the electroweak sector of the Standard Model at very low energies. Furthermore, precision measurements of spin-dependent atomic PNC can determine nuclear anapole moments and probe the weak force within the nucleus. Francium is an excellent candidate for precision measurements of atomic PNC due to its simple electronic structure and enhanced parity violation: both the optical PNC and anapole moment signals are expected to be over an order of magnitude larger than in cesium.

  9. Tracking channel-floodplain sediment exchange with conservative and non-conservative geochemical tracers

    NASA Astrophysics Data System (ADS)

    Belmont, Patrick; Stout, Justin

    2013-04-01

    Fine sediment is routed through landscapes and channel networks in a highly unsteady and non-uniform manner, potentially experiencing deposition and re-suspension many times during transport from source to sink. Developing a better understanding of sediment routing at the landscape scale is an intriguing challenge from a modeling perspective because it requires consideration of a multitude of processes that interact and vary in space and time. From an applied perspective, an improved understanding of sediment routing is essential for predicting how conservation and restoration practices within a watershed will influence water quality, to support land and water management decisions. Two key uncertainties in predicting sediment routing at the landscape scale are 1) determining the proportion of suspended sediment that is derived from terrestrial (soil) erosion versus channel (bank) erosion, and 2) constraining the proportion of sediment that is temporarily stored and re-suspended within the channel-floodplain complex. Sediment fingerprinting that utilizes a suite of conservative and non-conservative geochemical tracers associated with suspended sediment can provide insight regarding both of these key uncertainties. Here we present a model that tracks suspended sediment with associated conservative and non-conservative geochemical tracers. The model assumes that particle residence times are described by a bimodal distribution wherein some fraction of sediment is transported through the system in a relatively short time (< 1 year) and the remainder experiences temporary storage (of variable duration) within the channel-floodplain complex. We use the model to explore the downstream evolution of non-conservative tracers under equilibrium conditions (i.e., exchange between the channel and floodplain is allowed, but no net change in channel-floodplain storage can occur) to illustrate how the process of channel-floodplain storage and re-suspension can potentially bias

  10. A measurement of parity non-conserving optical rotation in atomic lead

    NASA Astrophysics Data System (ADS)

    Phipp, S. J.; Edwards, N. H.; Baird, P. E. G.; Nakayama, S.

    1996-05-01

    We report a measurement of parity non-conserving (PNC) optical rotation in the vicinity of the 1.279 0953-4075/29/9/028/img7 magnetic dipole transition in atomic lead. We obtain a value for the conventional parameter, 0953-4075/29/9/028/img8, with limits on the nuclear spin-dependent contribution set by the anapole constant 0953-4075/29/9/028/img9. The experimental results, when combined with the relevant atomic calculations, lead to a value for the mass of the 0953-4075/29/9/028/img10 boson or, alternatively, place a limit on physics beyond the standard model through the isospin-conserving parameter, S.

  11. Non-conservative GNSS satellite modeling: long-term orbit behavior

    NASA Astrophysics Data System (ADS)

    Rodriguez-Solano, C. J.; Hugentobler, U.; Steigenberger, P.; Sosnica, K.; Fritsche, M.

    2012-04-01

    Modeling of non-conservative forces is a key issue for precise orbit determination of GNSS satellites. Furthermore, mismodeling of these forces has the potential to explain orbit-related frequencies found in GPS-derived station coordinates and geocenter, as well as the observed bias in the SLR-GPS residuals. Due to the complexity of the non-conservative forces, usually they have been compensated by empirical models based on the real in-orbit behavior of the satellites. Recent studies have focused on the physical/analytical modeling of solar radiation pressure, Earth radiation pressure, thermal effects, antenna thrust, among different effects. However, it has been demonstrated that pure physical models fail to predict the real orbit behavior with sufficient accuracy. In this study we use a recently developed solar radiation pressure model based on the physical interaction between solar radiation and satellite, but also capable of fitting the GNSS tracking data, called adjustable box-wing model. Furthermore, Earth radiation pressure and antenna thrust are included as a priori acceleration. The adjustable parameters of the box-wing model are surface optical properties, the so-called Y-bias and a parameter capable of compensating for non-nominal orientation of the solar panels. Using the adjustable box-wing model a multi-year GPS/GLONASS solution has been computed, using a processing scheme derived from CODE (Center for Orbit Determination in Europe). This multi-year solution allows studying the long-term behavior of satellite orbits, box-wing parameters and geodetic parameters like station coordinates and geocenter. Moreover, the accuracy of GNSS orbits is assessed by using SLR data. This evaluation also allows testing, whether the current SLR-GPS bias could be further reduced.

  12. Effect of leucine-to-methionine substitutions on the diffraction quality of histone chaperone SET/TAF-Ibeta/INHAT crystals.

    PubMed

    Senda, Miki; Muto, Shinsuke; Horikoshi, Masami; Senda, Toshiya

    2008-10-01

    One of the most frequent problems in crystallization is poor quality of the crystals. In order to overcome this obstacle several methods have been utilized, including amino-acid substitutions of the target protein. Here, an example is presented of crystal-quality improvement by leucine-to-methionine substitutions. A variant protein with three amino-acid substitutions enabled improvement of the crystal quality of the histone chaperone SET/TAF-Ibeta/INHAT when combined with optimization of the cryoconditions. This procedure improved the resolution of the SET/TAF-Ibeta/INHAT crystals from around 5.5 to 2.3 A without changing the crystallization conditions. PMID:18931446

  13. Basic amino-acid side chains regulate transmembrane integrin signalling.

    PubMed

    Kim, Chungho; Schmidt, Thomas; Cho, Eun-Gyung; Ye, Feng; Ulmer, Tobias S; Ginsberg, Mark H

    2012-01-12

    Side chains of Lys/Arg near transmembrane domain (TMD) membrane-water interfaces can 'snorkel', placing their positive charge near negatively charged phospholipid head groups; however, snorkelling's functional effects are obscure. Integrin β TMDs have such conserved basic amino acids. Here we use NMR spectroscopy to show that integrin β(3)(Lys 716) helps determine β(3) TMD topography. The α(ΙΙb)β(3) TMD structure indicates that precise β(3) TMD crossing angles enable the assembly of outer and inner membrane 'clasps' that hold the αβ TMD together to limit transmembrane signalling. Mutation of β(3)(Lys 716) caused dissociation of α(ΙΙb)β(3) TMDs and integrin activation. To confirm that altered topography of β(3)(Lys 716) mutants activated α(ΙΙb)β(3), we used directed evolution of β(3)(K716A) to identify substitutions restoring default state. Introduction of Pro(711) at the midpoint of β(3) TMD (A711P) increased α(ΙΙb)β(3) TMD association and inactivated integrin α(ΙΙb)β(3)(A711P,K716A). β(3)(Pro 711) introduced a TMD kink of 30 ± 1° precisely at the border of the outer and inner membrane clasps, thereby decoupling the tilt between these segments. Thus, widely occurring snorkelling residues in TMDs can help maintain TMD topography and membrane-embedding, thereby regulating transmembrane signalling. PMID:22178926

  14. Pilot trial of branched-chain aminoacids in amyotrophic lateral sclerosis.

    PubMed

    Plaitakis, A; Smith, J; Mandeli, J; Yahr, M D

    1988-05-01

    22 patients with amyotrophic lateral sclerosis were entered into a double-blind, randomised, placebo-controlled trial of treatment with branched-chain aminoacids. 11 received daily 12 g L-leucine, 8 g L-isoleucine, and 6.4 g L-valine, by mouth, and the remainder received placebo. During the one-year trial, patients in the placebo group showed a linear decline in functional status consistent with the natural history of the disease. Those treated with aminoacids showed significant benefit in terms of maintenance of extremity muscle strength and continued ability to walk. PMID:2896868

  15. Noether's theorem for non-conservative Hamilton system based on El-Nabulsi dynamical model extended by periodic laws

    NASA Astrophysics Data System (ADS)

    Long, Zi-Xuan; Zhang, Yi

    2014-11-01

    This paper focuses on the Noether symmetries and the conserved quantities for both holonomic and nonholonomic systems based on a new non-conservative dynamical model introduced by El-Nabulsi. First, the El-Nabulsi dynamical model which is based on a fractional integral extended by periodic laws is introduced, and El-Nabulsi—Hamilton's canonical equations for non-conservative Hamilton system with holonomic or nonholonomic constraints are established. Second, the definitions and criteria of El-Nabulsi—Noether symmetrical transformations and quasi-symmetrical transformations are presented in terms of the invariance of El-Nabulsi—Hamilton action under the infinitesimal transformations of the group. Finally, Noether's theorems for the non-conservative Hamilton system under the El-Nabulsi dynamical system are established, which reveal the relationship between the Noether symmetry and the conserved quantity of the system.

  16. Mechanical damage to Escherichia coli cells in a model of amino-acid crystal fermentation.

    PubMed

    Okutani, Satoshi; Iwai, Takayoshi; Iwatani, Shintaro; Kondo, Kazuya; Osumi, Tsuyoshi; Tsujimoto, Nobuharu; Matsuno, Kiyoshi

    2012-04-01

    We investigated the mechanical damage to the Escherichia coli cell caused by polyvinyl chloride particles as a model of amino-acid crystal fermentation. Our results indicated that the glucose-consumption rate and the intracellular ATP concentration temporarily increased by the mechanical damage, and decreased after considerable damage had occurred on cell membrane. PMID:22153714

  17. cDNA-derived amino-acid sequence of a land turtle (Geochelone carbonaria) beta-chain hemoglobin.

    PubMed

    Bordin, S; Meza, A N; Saad, S T; Ogo, S H; Costa, F F

    1997-06-01

    The cDNA sequence encoding the turtle Geochelone carbonaria beta-chain was determinated. The isolation of hemoglobin mRNA was based on degenerate primers' PCR in combination with 5'- and 3'-RACE protocol. The full length cDNA is 615 bp with the ATG start codon at position 53 and TGA stop codon at position 495; The AATAAA polyadenylation signal is found at position 599. The deduced polypeptyde contains 146 amino-acid residues. The predicted amino acid sequence shares 83% identity with the beta-globin of a related specie, the aquatic turtle C. p. belli. Otherwise, identity is higher when compared with chicken beta-Hb (80%) than with other reptilian orders (Squamata, 69%, and Crocodilia, 61%). Compared with human HbA, there is 67% identity, and at least three amino acid substitutions could be of some functional significance (Glu43 beta-->Ser, His116 beta-->Thr and His143 beta-->Leu). To our knowledge this represents the first cDNA sequence of a reptile globin gene described. PMID:9238523

  18. About an H-theorem for systems with non-conservative interactions

    NASA Astrophysics Data System (ADS)

    Marini Bettolo Marconi, Umberto; Puglisi, Andrea; Vulpiani, Angelo

    2013-08-01

    We present some arguments in favor of an H-theorem for a generalization of the Boltzmann equation including non-conservative interactions and a linear Fokker-Planck-like thermostatting term. Such a non-linear equation describing the evolution of the single particle probability Pi(t) of being in state i at time t is a suitable model for granular gases and is referred to here as the Boltzmann-Fokker-Planck (BFP) equation. The conjectured H-functional, which appears to be non-increasing, is HC(t) = ∑iPi(t)lnPi(t)/Πi with Πi = limt→∞Pi(t), in analogy with the H-functional of Markov processes. The extension to continuous states is straightforward. A simple proof can be given for the elastic BFP equation. A semi-analytical proof is also offered for the BFP equation for so-called inelastic Maxwell molecules. Other evidence is obtained by solving particular BFP cases through numerical integration or through ‘particle schemes’ such as the direct simulation Monte Carlo.

  19. Rolling vs. Sliding: The inclusion of non-conservative work in the classic comparison

    NASA Astrophysics Data System (ADS)

    Chediak, Alex; Buehler, Terry

    2010-03-01

    A semester-long mechanics course typically covers moment of inertia, angular velocity, and rolling. A classic comparison is made between rolling without slipping and sliding without friction. In either case, no non-conservation work is performed---all the gravitational potential energy that the rolling or sliding object possesses at the top of the incline plane is converted into kinetic energy. In the case of the sliding object, the kinetic energy term is simply .5ex1 -.1em/ -.15em.25ex2 mv^2. In the case of the rolling object, the kinetic energy term is .5ex1 -.1em/ -.15em.25ex2 mv^2 + .5ex1 -.1em/ -.15em.25ex2 Iφ^2. The friction here is static not kinetic, so it does no mechanical work. Since the sliding object has no angular velocity, its linear velocity is greater than that of the rolling object, and it reaches the bottom of the track faster. But if a rolling and sliding object, each of the same material, were to race down an incline plane, which would win? The answer depends on the effective coefficient of friction, C. If C > μs, which will occur at angles approaching 90^o, the rolling object slips. And if C < μk, the rolling object has a greater linear acceleration and wins the race to the bottom. Experimental results to verify a theoretical model (including the dependency on incline angle) will also be presented.

  20. Non-conservative behavior of fluorescent dissolved organic matter (FDOM) within a subterranean estuary

    NASA Astrophysics Data System (ADS)

    Suryaputra, I. G. N. A.; Santos, I. R.; Huettel, M.; Burnett, W. C.; Dittmar, T.

    2015-11-01

    The role of submarine groundwater discharge (SGD) in releasing fluorescent dissolved organic matter (FDOM) to the coastal ocean and the possibility of using FDOM as a proxy for dissolved organic carbon (DOC) was investigated in a subterranean estuary in the northeastern Gulf of Mexico (Turkey Point, Florida). FDOM was continuously monitored for three weeks in shallow beach groundwater and in the adjacent coastal ocean. Radon (222Rn) was used as a natural groundwater tracer. FDOM and DOC correlated in groundwater and seawater samples, implying that FDOM may be a proxy of DOC in waters influenced by SGD. A mixing model using salinity as a seawater tracer revealed FDOM production in the high salinity region of the subterranean estuary. This production was probably a result of infiltration and transformation of labile marine organic matter in the beach sediments. The non-conservative FDOM behavior in this subterranean estuary differs from most surface estuaries where FDOM typically behaves conservatively. At the study site, fresh and saline SGD delivered about 1800 mg d-1 of FDOM (quinine equivalents) to the coastal ocean per meter of shoreline. About 11% of this input was related to fresh SGD, while 89% were related to saline SGD resulting from FDOM production within the shallow aquifer. If these fluxes are representative of the Florida Gulf Coast, SGD-derived FDOM fluxes would be equivalent to at least 18% of the potential regional riverine FDOM inputs. To reduce uncertainties related to the scarcity of FDOM data, further investigations of river and groundwater FDOM inputs in Florida and elsewhere are necessary.

  1. Tracing non-conservative mass transfer eras in close binaries from observed period variations

    NASA Astrophysics Data System (ADS)

    Nanouris, N.; Kalimeris, A.; Antonopoulou, E.; Rovithis-Livaniou, H.

    2013-09-01

    The pure information directly taken from the observed orbital evolution of eclipsing binary stars (centuries at most) is valuable for the study of many important physical mechanisms related to the stellar structure. Especially in the case of eclipsing binary systems, this may happen by monitoring their eclipse timing variations, i.e. by means of an O-C diagram analysis. As long as a binary system attains a semi-detached configuration, material begins to flow from the component that fills its Roche lobe toward its mate through the first Lagrangian (L1) point. Here, we examine two non conservative mass transfer (MT) paths. The MT process is then accompanied by mass and angular momentum loss from the system. In the first path, angular momentum is removed through a hot spot which re-emits part of the incoming material, and in the second, angular momentum is carried away via an outer Lagrangian point (L2/L3) due to the small accumulating efficiency of the accretion disk surrounding the gainer. Dealing with the less massive component as the donor in the latter path, it is shown that there is always a critical mass ratio over which the period is expected to decrease, contrary to what the fully conservative MT predicts. Consistent with our expectations, the critical values become progressively smaller as the degree of liberalism is gradually widened. The O-C diagram of several semi-detached systems, expecting to experience a liberal era, is individually examined aiming to estimate both the mass transfer and the mass loss rate.

  2. Non-Conserved Residues in Clostridium acetobutylicum tRNAAla Contribute to tRNA Tuning for Efficient Antitermination of the alaS T Box Riboswitch

    PubMed Central

    Liu, Liang-Chun; Grundy, Frank J.; Henkin, Tina M.

    2015-01-01

    The T box riboswitch regulates expression of amino acid-related genes in Gram-positive bacteria by monitoring the aminoacylation status of a specific tRNA, the binding of which affects the folding of the riboswitch into mutually exclusive terminator or antiterminator structures. Two main pairing interactions between the tRNA and the leader RNA have been demonstrated to be necessary, but not sufficient, for efficient antitermination. In this study, we used the Clostridium acetobutylicum alaS gene, which encodes alanyl-tRNA synthetase, to investigate the specificity of the tRNA response. We show that the homologous C. acetobutylicum tRNAAla directs antitermination of the C. acetobutylicum alaS gene in vitro, but the heterologous Bacillus subtilis tRNAAla (with the same anticodon and acceptor end) does not. Base substitutions at positions that vary between these two tRNAs revealed synergistic and antagonistic effects. Variation occurs primarily at positions that are not conserved in tRNAAla species, which indicates that these non-conserved residues contribute to optimal antitermination of the homologous alaS gene. This study suggests that elements in tRNAAla may have coevolved with the homologous alaS T box leader RNA for efficient antitermination. PMID:26426057

  3. [Aminoacids and hyaluronic acid in topical treatment of bedsores. Clinical report].

    PubMed

    Chiummariello, S; Arleo, S; Alfano, C

    2010-05-01

    Pressure ulcers are evolutive tissue of the skin, derma and subcutaneous layer. If not treated properly, but sometimes despite that, they may even reach muscles and bones. Nutritional status of the patient is the most important and potentially reversible factor which can contribute to wound recovery. Several studies underline in particular the importance of the proteic and caloric intake in order to stimulate the formation of granulation tissue and collagen. We thought giving the nutrients for wound repair directly on the wound bed, topically, therefore using the wound bed as exchange surface and presuming the wounded tissues are able to absorb, metabolize and ultimately use the aminoacids to repair the damage. The goal of our work is to describe the clinical case patient treated with a new active wound dressing releasing aminoacids and hyaluronic acid. PMID:20615371

  4. New Insights into CO2 Absorption Mechanisms with Amino-Acid Ionic Liquids.

    PubMed

    Yang, Qiwei; Wang, Zhiping; Bao, Zongbi; Zhang, Zhiguo; Yang, Yiwen; Ren, Qilong; Xing, Huabin; Dai, Sheng

    2016-04-21

    The last decade saw an explosion of interest in using amine-functionalized materials for CO2 capture and conversion, and it is of great importance to elucidate the relationship between the molecular structure of amine-functionalized materials and their CO2 capacity. In this work, based on a new quantitative analysis method for the CO2 absorption mechanism of amino-acid ionic liquids (ILs) and quantum chemical calculations, we show that the small difference in the local structure of amine groups in ILs could lead to much different CO2 absorption mechanisms, which provides an opportunity for achieving higher CO2 capacity by structure design. This work revealed that the actual CO2 absorption mechanism by amino-acid ILs goes beyond the apparent CO2 /amine stoichiometry; a rigid ring structure around the amine group in ILs creates a unique electrostatic environment that inhibits the deprotonation of carbamic acid and enables actually equimolar CO2 /amine absorption. PMID:27061812

  5. Plasma amino-acids in hereditary retinal disease. Ornithine, lysine, and taurine.

    PubMed Central

    Berson, E. L.; Schmidt, S. Y.; Rabin, A. R.

    1976-01-01

    Plasma free amino-acids were measured in 41 patients with hereditary chorio-retinal degenerations including 26 with retinitis pigmentosa and five with gyrate atrophy of the choroid, six relatives of patients with gyrate atrophy, and 13 normal subjects. Patients with gyrate atrophy had very increased levels of ornithine and slightly decreased mean lysine values. Most relatives had slightly increased ornithine. Taurine, known to be deficient in the plasma of casein-fed cats with photoreceptor degeneration, was normal in all patients. Amino-acid precursors and metabolites of ornithine and taurine were also normal in the plasma. Although the association of high ornithine and gyrate atrophy appears constant, high levels of ornithine alone do not necessarily lead to this degeneration; one patient with known hyperammonaemia, homocitrullinuria and a tenfold increase in plasma ornithine was found to have a normal fundus appearance and normal electroretinogram. PMID:1268174

  6. Multi-scale coarse-graining of non-conservative interactions in molecular liquids

    SciTech Connect

    Izvekov, Sergei Rice, Betsy M.

    2014-03-14

    A new bottom-up procedure for constructing non-conservative (dissipative and stochastic) interactions for dissipative particle dynamics (DPD) models is described and applied to perform hierarchical coarse-graining of a polar molecular liquid (nitromethane). The distant-dependent radial and shear frictions in functional-free form are derived consistently with a chosen form for conservative interactions by matching two-body force-velocity and three-body velocity-velocity correlations along the microscopic trajectories of the centroids of Voronoi cells (clusters), which represent the dissipative particles within the DPD description. The Voronoi tessellation is achieved by application of the K-means clustering algorithm at regular time intervals. Consistently with a notion of many-body DPD, the conservative interactions are determined through the multi-scale coarse-graining (MS-CG) method, which naturally implements a pairwise decomposition of the microscopic free energy. A hierarchy of MS-CG/DPD models starting with one molecule per Voronoi cell and up to 64 molecules per cell is derived. The radial contribution to the friction appears to be dominant for all models. As the Voronoi cell sizes increase, the dissipative forces rapidly become confined to the first coordination shell. For Voronoi cells of two and more molecules the time dependence of the velocity autocorrelation function becomes monotonic and well reproduced by the respective MS-CG/DPD models. A comparative analysis of force and velocity correlations in the atomistic and CG ensembles indicates Markovian behavior with as low as two molecules per dissipative particle. The models with one and two molecules per Voronoi cell yield transport properties (diffusion and shear viscosity) that are in good agreement with the atomistic data. The coarser models produce slower dynamics that can be appreciably attributed to unaccounted dissipation introduced by regular Voronoi re-partitioning as well as by larger

  7. A Roe-like numerical method for weakly hyperbolic systems of equations in conservation and non-conservation form

    NASA Astrophysics Data System (ADS)

    Smith, Timothy A.; Petty, David J.; Pantano, Carlos

    2016-07-01

    We describe a scheme for the numerical approximation of uniformly or locally weakly hyperbolic systems of equations in conservation and non-conservation forms. The strategy focuses on generalizations of the Roe scheme for non-conservation systems that can be considered as upstream differencing discretizations. The present work explicitly treats an advection matrix that is not diagonalizable by extending previous ideas that introduce a perturbation into the weakly hyperbolic problem to convert it to a nearby strongly hyperbolic problem. The perturbative expansion allows one to identify and remove the terms that would otherwise result in an apparent singularity and isolate the regular part of the numerical method. The performance of the method is showcased for uniformly and locally weakly hyperbolic systems in one and two dimensions. Generalization to higher dimensional systems can be performed by following the usual practice of dimension-by-dimension splitting.

  8. Atomic parity non-conservation: the francium anapole project of the FrPNC collaboration at TRIUMF

    NASA Astrophysics Data System (ADS)

    Aubin, S.; Behr, J. A.; Collister, R.; Flambaum, V. V.; Gomez, E.; Gwinner, G.; Jackson, K. P.; Melconian, D.; Orozco, L. A.; Pearson, M. R.; Sheng, D.; Sprouse, G. D.; Tandecki, M.; Zhang, J.; Zhao, Y.

    2013-03-01

    We present a method for measuring the nuclear anapole in a string of francium isotopes. The anapole is a parity non-conserving electromagnetic moment that enables parity-forbidden transitions between ground state hyperfine levels of an atom. The experiment is run by the FrPNC collaboration and relies on a beam of artificially-produced francium from the ISAC facility at TRIUMF.

  9. Amino-acid substitutions at codon 13 of the N-ras oncogene in human acute myeloid leukaemia

    NASA Astrophysics Data System (ADS)

    Bos, Johannes L.; Toksoz, Deniz; Marshall, Christopher J.; Verlaan-de Vries, Matty; Veeneman, Gerrit H.; van der Eb, Alex J.; van Boom, Jacques H.; Janssen, Johannes W. G.; Steenvoorden, Ada C. M.

    1985-06-01

    DNAs from four out of five patients with acute myeloid leukaemia (AML) tested by an in vivo selection assay in nude mice using transfected mouse NIH 3T3 cells were found to contain an activated N-ras oncogene. Using a set of synthetic oligonucleotide probes, we have detected a mutation at codon 13 in all four genes. The same codon is mutated in an additional AML DNA that is positive in the focus-formation assay on 3T3 cells. DNA from the peripheral blood of one patient in remission does not contain a codon 13 mutation.

  10. Skin Substitutes

    PubMed Central

    Howe, Nicole; Cohen, George

    2014-01-01

    In a relatively short timespan, a wealth of new skin substitutes made of synthetic and biologically derived materials have arisen for the purpose of wound healing of various etiologies. This review article focuses on providing an overview of skin substitutes including their indications, contraindications, benefits, and limitations. The result of this overview was an appreciation of the vast array of options available for clinicians, many of which did not exist a short time ago. Yet, despite the rapid expansion this field has undergone, no ideal skin substitute is currently available. More research in the field of skin substitutes and wound healing is required not only for the development of new products made of increasingly complex biomolecular material, but also to compare the existing skin substitutes. PMID:25371771

  11. Surveying determinants of protein structure designability across different energy models and amino-acid alphabets: A consensus

    NASA Astrophysics Data System (ADS)

    Buchler, Nicolas E. G.; Goldstein, Richard A.

    2000-02-01

    A variety of analytical and computational models have been proposed to answer the question of why some protein structures are more "designable" (i.e., have more sequences folding into them) than others. One class of analytical and statistical-mechanical models has approached the designability problem from a thermodynamic viewpoint. These models highlighted specific structural features important for increased designability. Furthermore, designability was shown to be inherently related to thermodynamically relevant energetic measures of protein folding, such as the foldability F and energy gap Δ10. However, many of these models have been done within a very narrow focus: Namely, pair-contact interactions and two-letter amino-acid alphabets. Recently, two-letter amino-acid alphabets for pair-contact models have been shown to contain designability artifacts which disappear for larger-letter amino-acid alphabets. In addition, a solvation model was demonstrated to give identical designability results to previous two-letter amino-acid alphabet pair-contact models. In light of these discordant results, this report synthesizes a broad consensus regarding the relationship between specific structural features, foldability F, energy gap Δ10, and structure designability for different energy models (pair-contact vs solvation) across a wide range of amino-acid alphabets. We also propose a novel measure Zdk which is shown to be well correlated to designability. Finally, we conclusively demonstrate that two-letter amino-acid alphabets for pair-contact models appear to be solvation models in disguise.

  12. Wide bandsaw blade under cutting conditions. Part III: Stability of a plate moving in its plane while subjected to non-conservative cutting forces

    NASA Astrophysics Data System (ADS)

    Lengoc, L.; McCallion, H.

    1995-09-01

    This study provides yet another possible mechanism for instability of bandsaw blades during sawing, namely dynamic instability of a moving plate when subjected to non-conservative tangential edge loading. In previous publications, the effect of non-conservative edge loading has been neglected; only the divergent buckling and the parametric instability have been considered as causes of unstable bandsaw blade motion. However, the non-conservative loading due to sawing can excite a flutter-type instability, similar to flutter in aeroplane wings. The extended Galerkin method is used to discretize the equation of motion, and a non-self-adjoint eigenvalue solver is employed to find the solutions.

  13. A new efficient formulation of the HLLEM Riemann solver for general conservative and non-conservative hyperbolic systems

    NASA Astrophysics Data System (ADS)

    Dumbser, Michael; Balsara, Dinshaw S.

    2016-01-01

    In this paper a new, simple and universal formulation of the HLLEM Riemann solver (RS) is proposed that works for general conservative and non-conservative systems of hyperbolic equations. For non-conservative PDE, a path-conservative formulation of the HLLEM RS is presented for the first time in this paper. The HLLEM Riemann solver is built on top of a novel and very robust path-conservative HLL method. It thus naturally inherits the positivity properties and the entropy enforcement of the underlying HLL scheme. However, with just the slight additional cost of evaluating eigenvectors and eigenvalues of intermediate characteristic fields, we can represent linearly degenerate intermediate waves with a minimum of smearing. For conservative systems, our paper provides the easiest and most seamless path for taking a pre-existing HLL RS and quickly and effortlessly converting it to a RS that provides improved results, comparable with those of an HLLC, HLLD, Osher or Roe-type RS. This is done with minimal additional computational complexity, making our variant of the HLLEM RS also a very fast RS that can accurately represent linearly degenerate discontinuities. Our present HLLEM RS also transparently extends these advantages to non-conservative systems. For shallow water-type systems, the resulting method is proven to be well-balanced. Several test problems are presented for shallow water-type equations and two-phase flow models, as well as for gas dynamics with real equation of state, magnetohydrodynamics (MHD & RMHD), and nonlinear elasticity. Since our new formulation accommodates multiple intermediate waves and has a broader applicability than the original HLLEM method, it could alternatively be called the HLLI Riemann solver, where the "I" stands for the intermediate characteristic fields that can be accounted for.

  14. The Modeling of Time-Varying Stream Water Age Distributions: Preliminary Investigations with Non-Conservative Solutes

    NASA Astrophysics Data System (ADS)

    Wilusz, D. C.; Harman, C. J.; Ball, W. P.

    2014-12-01

    Modeling the dynamics of chemical transport from the landscape to streams is necessary for water quality management. Previous work has shown that estimates of the distribution of water age in streams, the transit time distribution (TTD), can improve prediction of the concentration of conservative tracers (i.e., ones that "follow the water") based on upstream watershed inputs. A major challenge however has been accounting for climate and transport variability when estimating TDDs at the catchment scale. In this regard, Harman (2014, in review) proposed the Omega modeling framework capable of using watershed hydraulic fluxes to approximate the time-varying TTD. The approach was previously applied to the Plynlimon research watershed in Wales to simulate stream concentration dynamics of a conservative tracer (chloride) including 1/f attenuation of the power spectra density. In this study we explore the extent to which TTDs estimated by the Omega model vary with the concentration of non-conservative tracers (i.e., ones whose concentrations are also affected by transformations and interactions with other phases). First we test the hypothesis that the TTD calibrated in Plynlimon can explain a large part of the variation in non-conservative stream water constituents associated with storm flow (acidity, Al, DOC, Fe) and base flow (Ca, Si). While controlling for discharge, we show a correlation between the percentage of water of different ages and constituent concentration. Second, we test the hypothesis that TTDs help explain variation in stream nitrate concentration, which is of particular interest for pollution control but can be highly non-conservative. We compare simulation runs from Plynlimon and the agricultural Choptank watershed in Maryland, USA. Following a top-down approach, we estimate nitrate concentration as if it were a conservative tracer and examine the structure of residuals at different temporal resolutions. Finally, we consider model modifications to

  15. Sensitivity test of a blue-detuned dipole trap designed for parity non-conservation measurements in Fr.

    PubMed

    Sheng, D; Zhang, J; Orozco, L A

    2012-04-01

    A dynamic blue-detuned optical dipole trap with stable (87)Rb atoms produces a differential ac Stark shift of 18 Hz in the ground state hyperfine transition, and it preserves the ground state hyperfine superpositions for a long coherence time of 180 ms. The trapped atoms undergoing microwave Rabi oscillations are sensitive to a small signal, artificially generated with a second microwave source, phase locked to the first allowing a simple and effective method for determining signal-to-noise ratio limits through interference techniques. This provides an excellent means of calibrating sensitivity in experiments such as our ongoing Fr parity non-conservation measurement. PMID:22559514

  16. Sensitivity test of a blue-detuned dipole trap designed for parity non-conservation measurements in Fr

    NASA Astrophysics Data System (ADS)

    Sheng, D.; Zhang, J.; Orozco, L. A.

    2012-04-01

    A dynamic blue-detuned optical dipole trap with stable 87Rb atoms produces a differential ac Stark shift of 18 Hz in the ground state hyperfine transition, and it preserves the ground state hyperfine superpositions for a long coherence time of 180 ms. The trapped atoms undergoing microwave Rabi oscillations are sensitive to a small signal, artificially generated with a second microwave source, phase locked to the first allowing a simple and effective method for determining signal-to-noise ratio limits through interference techniques. This provides an excellent means of calibrating sensitivity in experiments such as our ongoing Fr parity non-conservation measurement.

  17. Accurate Measurement of the Effects of All Amino-Acid Mutations on Influenza Hemagglutinin

    PubMed Central

    Doud, Michael B.; Bloom, Jesse D.

    2016-01-01

    Influenza genes evolve mostly via point mutations, and so knowing the effect of every amino-acid mutation provides information about evolutionary paths available to the virus. We and others have combined high-throughput mutagenesis with deep sequencing to estimate the effects of large numbers of mutations to influenza genes. However, these measurements have suffered from substantial experimental noise due to a variety of technical problems, the most prominent of which is bottlenecking during the generation of mutant viruses from plasmids. Here we describe advances that ameliorate these problems, enabling us to measure with greatly improved accuracy and reproducibility the effects of all amino-acid mutations to an H1 influenza hemagglutinin on viral replication in cell culture. The largest improvements come from using a helper virus to reduce bottlenecks when generating viruses from plasmids. Our measurements confirm at much higher resolution the results of previous studies suggesting that antigenic sites on the globular head of hemagglutinin are highly tolerant of mutations. We also show that other regions of hemagglutinin—including the stalk epitopes targeted by broadly neutralizing antibodies—have a much lower inherent capacity to tolerate point mutations. The ability to accurately measure the effects of all influenza mutations should enhance efforts to understand and predict viral evolution. PMID:27271655

  18. Exploring the evolution of standard amino-acid alphabet: When genomics meets thermodynamics

    SciTech Connect

    Zhang, Hong-Yu . E-mail: zhanghy@sdut.edu.cn

    2007-08-03

    One of the most intriguing aspects of life is that despite the diversified apparent shapes, similar building blocks and infrastructures, such as standard amino acids and canonical genetic codes, are shared by most life on Earth. Thus, it is challenging to explore: why nature just selects these building blocks and strategies from numerous candidates to construct life? Was this deterministic or fortuitous? Thanks to the rapid progress in genomics, bioinformatics and synthetic biology, more and more basic principles underlying life design and construction were disclosed in the past decade. However, since the origin of early life is substantially a chemical process, to understand the enigma of life origin, chemists' efforts can not be neglected. In this paper, we focus on the evolution of standard amino-acid alphabet and indicate that chemistry, especially thermodynamics, is indeed critical to understanding the forming mechanisms of amino-acid alphabet. It is revealed that nature prefers low free energy and thus ubiquitous (cheap) small amino acids when beginning to build life, which is compatible with many recent findings from genomics and bioinformatics.

  19. A stress assembly that confers cell viability by preserving ERES components during amino-acid starvation

    PubMed Central

    Zacharogianni, Margarita; Aguilera Gomez, Angelica; Veenendaal, Tineke; Smout, Jan; Rabouille, Catherine

    2014-01-01

    Nutritional restriction leads to protein translation attenuation that results in the storage and degradation of free mRNAs in cytoplasmic assemblies. In this study, we show in Drosophila S2 cells that amino-acid starvation also leads to the inhibition of another major anabolic pathway, the protein transport through the secretory pathway, and to the formation of a novel reversible non-membrane bound stress assembly, the Sec body that incorporates components of the ER exit sites. Sec body formation does not depend on membrane traffic in the early secretory pathway, yet requires both Sec23 and Sec24AB. Sec bodies have liquid droplet-like properties, and they act as a protective reservoir for ERES components to rebuild a functional secretory pathway after re-addition of amino-acids acting as a part of a survival mechanism. Taken together, we propose that the formation of these structures is a novel stress response mechanism to provide cell viability during and after nutrient stress. DOI: http://dx.doi.org/10.7554/eLife.04132.001 PMID:25386913

  20. Accurate Measurement of the Effects of All Amino-Acid Mutations on Influenza Hemagglutinin.

    PubMed

    Doud, Michael B; Bloom, Jesse D

    2016-01-01

    Influenza genes evolve mostly via point mutations, and so knowing the effect of every amino-acid mutation provides information about evolutionary paths available to the virus. We and others have combined high-throughput mutagenesis with deep sequencing to estimate the effects of large numbers of mutations to influenza genes. However, these measurements have suffered from substantial experimental noise due to a variety of technical problems, the most prominent of which is bottlenecking during the generation of mutant viruses from plasmids. Here we describe advances that ameliorate these problems, enabling us to measure with greatly improved accuracy and reproducibility the effects of all amino-acid mutations to an H1 influenza hemagglutinin on viral replication in cell culture. The largest improvements come from using a helper virus to reduce bottlenecks when generating viruses from plasmids. Our measurements confirm at much higher resolution the results of previous studies suggesting that antigenic sites on the globular head of hemagglutinin are highly tolerant of mutations. We also show that other regions of hemagglutinin-including the stalk epitopes targeted by broadly neutralizing antibodies-have a much lower inherent capacity to tolerate point mutations. The ability to accurately measure the effects of all influenza mutations should enhance efforts to understand and predict viral evolution. PMID:27271655

  1. Non-conservative behaviors of chromophoric dissolved organic matter in a turbid estuary: Roles of multiple biogeochemical processes

    NASA Astrophysics Data System (ADS)

    Yang, Liyang; Guo, Weidong; Hong, Huasheng; Wang, Guizhi

    2013-11-01

    Chromophoric dissolved organic matter (CDOM) may show notable non-conservative behaviors in many estuaries due to a variety of biogeochemical processes. The partition between CDOM and chromophoric particulate organic matter (CPOM) was examined in the Jiulong Estuary (China) using absorption and fluorescence spectroscopy, which was also compared with microbial and photochemical degradations. The absorption coefficient of water-soluble CPOM (aCPOM(280)) at ambient Milli-Q water pH (6.1) ranged from 0.11 to 7.94 m-1 in the estuary and was equivalent to 5-101% of CDOM absorption coefficient. The aCPOM(280) correlated significantly with the concentration of suspended particulate matter and was highest in the bottom water of turbidity maximum zone. Absorption spectral slope (S275-295) and slope ratio (SR) correlated positively with salinity for both CPOM and CDOM, suggesting decreases in the average molecular weight with increasing salinity. The adsorption of CDOM to re-suspended sediments (at 500 mg L-1) within 2 h was equivalent to 4-26% of the initial aCDOM(280). The adsorption of CDOM to particles was less selective with respect to various CDOM constituents, while the microbial degradation resulted decreases in S275-295 and SR of CDOM and preferential removal of protein-like components. The partition between CPOM and CDOM represented a rapid and important process for the non-conservative behavior of CDOM in turbid estuaries.

  2. Hydrophobicity, expressivity and aromaticity are the major trends of amino-acid usage in 999 Escherichia coli chromosome-encoded genes.

    PubMed Central

    Lobry, J R; Gautier, C

    1994-01-01

    Multivariate analysis of the amino-acid compositions of 999 chromosome-encoded proteins from Escherichia coli showed that three main factors influence the variability of amino-acid composition. The first factor was correlated with the global hydrophobicity of proteins, and it discriminated integral membrane proteins from the others. The second factor was correlated with gene expressivity, showing a bias in highly expressed genes towards amino-acids having abundant major tRNAs. Just as highly expressed genes have reduced codon diversity in protein coding sequences, so do they have a reduced diversity of amino-acid choice. This showed that translational constraints are important enough to affect the global amino-acid composition of proteins. The third factor was correlated with the aromaticity of proteins, showing that aromatic amino-acid content is highly variable. PMID:8065933

  3. Solvent substitution

    SciTech Connect

    Not Available

    1990-01-01

    The DOE Environmental Restoration and Waste Management Office of Technology Development and the Air Force Engineering and Services Center convened the First Annual International Workshop on Solvent Substitution on December 4--7, 1990. The primary objectives of this joint effort were to share information and ideas among attendees in order to enhance the development and implementation of required new technologies for the elimination of pollutants associated with industrial use of hazardous and toxic solvents; and to aid in accelerating collaborative efforts and technology transfer between government and industry for solvent substitution. There were workshop sessions focusing on Alternative Technologies, Alternative Solvents, Recovery/Recycling, Low VOC Materials and Treatment for Environmentally Safe Disposal. The 35 invited papers presented covered a wide range of solvent substitution activities including: hardware and weapons production and maintenance, paint stripping, coating applications, printed circuit boards, metal cleaning, metal finishing, manufacturing, compliance monitoring and process control monitoring. This publication includes the majority of these presentations. In addition, in order to further facilitate information exchange and technology transfer, the US Air Force and DOE solicited additional papers under a general Call for Papers.'' These papers, which underwent review and final selection by a peer review committee, are also included in this combined Proceedings/Compendium. For those involved in handling, using or managing hazardous and toxic solvents, this document should prove to be a valuable resource, providing the most up-to-date information on current technologies and practices in solvent substitution. Individual papers are abstracted separated.

  4. Thermodynamics of helix-coil transitions in amino-acid homopolymers studied by multicanonical algorithms

    NASA Astrophysics Data System (ADS)

    Hansmann, Ulrich H. E.; Okamoto, Yuko

    1996-03-01

    Thermodynamics of helix-coil transitions in amino-acid homopolymers are studied by the multicanonical algorithms. Homopolymers of length 10 are considered for three characteristic amino acids, alanine (helix former), valine (helix indifferent), and glycine (helix breaker). For alanine other lengths (15 and 20) are also considered in order to examine the length dependence. From one multicanonical production run with completely random initial conformations, we have obtained various thermodynamic quantities (average helix length, specific heat, etc.) as functions of temperature. The results, though preliminary, suggest that the helix-coil transition for poly-alanine is second-order, while the nature of phase transition is not clear for poly-valine and poly-glycine.

  5. Alkylamine-Dependent Amino-Acid Oxidation by Lysine Monooxygenase—Fragmented Substrate of Oxygenase

    PubMed Central

    Yamamoto, Shozo; Yamauchi, Takashi; Hayaishi, Osamu

    1972-01-01

    Lysine monooxygenase catalyzes the oxygenative decarboxylation of L-lysine and produces a corresponding acid amide. L-Alanine was inactive as substrate. However, when propylamine was present, oxidation, but not oxygenation, of alanine was demonstrated with the oxygenase. Alanine was converted to pyruvate, with the liberation of ammonia and hydrogen peroxide, but propylamine remained unchanged. Other α-monoamino acids were also oxidized in the presence of alkylamines with various carbon chain lengths. The highest oxidase activity was observed when the total chain length of both amino acid and amine was nearly identical with that of lysine. Available evidence indicates that the amine-dependent amino-acid oxidase activity is associated with the lysine oxygenase activity. PMID:4509334

  6. Theory of Metastable State Relaxation for Non-Critical Binary Systems with Non-Conserved Order Parameter

    NASA Technical Reports Server (NTRS)

    Izmailov, Alexander; Myerson, Allan S.

    1993-01-01

    A new mathematical ansatz for a solution of the time-dependent Ginzburg-Landau non-linear partial differential equation is developed for non-critical systems such as non-critical binary solutions (solute + solvent) described by the non-conserved scalar order parameter. It is demonstrated that in such systems metastability initiates heterogeneous solute redistribution which results in formation of the non-equilibrium singly-periodic spatial solute structure. It is found how the time-dependent period of this structure evolves in time. In addition, the critical radius r(sub c) for solute embryo of the new solute rich phase together with the metastable state lifetime t(sub c) are determined analytically and analyzed.

  7. ERK1 nucleocytoplasmic shuttling rate depends on specific N-terminal aminoacids

    SciTech Connect

    Marchi, Matilde; NEST-INFM, Scuola Normale Superiore, Pisa ; Pancrazi, Laura; Maffei, Margherita; Institute of Food Science CNR, Avellino ; Ratto, G. Michele; Costa, Mario

    2010-07-23

    Despite ERK1 and ERK2 were considered interchangeable isoforms for a long time, their roles are now emerging as only partially overlapping. We recently reported that the nucleocytoplasmic trafficking of GFP-tagged ERK1 is slower than that of ERK2, this difference being caused by a unique domain of ERK1 located at its N-terminus (ERK1-Nt). In the present report we further investigated this issue by asking which were the specific aminoacids involved in such process. By photobleaching strategy, we demonstrated that ERK1-Nt is a domain capable to slow down the nucleocytoplasmic shuttling rate even of a small cargo protein. ERK1-Nt was then dissected into three regions as follows: 1 (aa 1-9), 2 (aa 10-29) and 3, (aa 30-39) that were deleted or mutated at specific sites. Dynamic imaging assessment of the role played by each region in determining the shuttling rate revealed that: region 1 has no significant role, region 2 and specific aminoacids of region 3 (V{sub 31}, K{sub 33,} P{sub 36}) are critical, but singularly do not totally account for the difference in the shuttling rate between ERK1 and 2. Finally, we demonstrated that the nucleocytoplasmic shuttling rate of a passively diffusing protein (mRED) is inversely related to ERK1-Nt-GFP concentrations inside the cell, thus suggesting that ERK1-Nt-GFP occupies the nuclear pore perhaps because of an important affinity of ERK1-Nt for nucleoporins. In conclusion, ERK1-Nt is a domain able per se to confer a slower shuttling rate to a cargo protein. Specific regions within this domain were identified as responsible for this biophysical property.

  8. Vesicles from pH-regulated reversible gemini amino-acid surfactants as nanocapsules for delivery.

    PubMed

    Lv, Jing; Qiao, Weihong; Li, Zongshi

    2016-10-01

    Reversible transition from micelles to vesicles by regulating pH were realized by gemini amino-acid surfactants N,N'-dialkyl-N,N'-diacetate ethylenediamine. Measurement results of ζ-potential at different pH and DLS at varying solvents revealed that the protonation between H(+) and double NCH2COO(-) groups (generating NH(+)CH2COO(-)), expressed as pKa1 and pKa2, is the key driving force to control the aggregation behaviors of gemini surfactant molecule. Effect of pH on the bilayer structure was studied in detail by using steady-state fluorescence spectroscopy of hydrophobic pyrene and Coumarin 153 (C153) respectively and fluorescence resonance energy transfer (FRET) from C153 to Rhodamine 6G (R6G). Various pH-regulated and pH-reversible self-assemblies were obtained in one surfactant system. Vitamin D3 was encapsulated in vesicle bilayers to form nano-VD3-capsules as VD3 supplement agent for health care products. By using the electrostatic attraction between Ca(2+) and double -COO(-) groups, nano-VD3-capsules with Ca(2+) coated outermost layers were prepared as a formulation for VD3 and calcium co-supplement agent. DLS and TEM were performed to check stability and morphology of the nano-capsules. It is concluded that the pH-regulated gemini amino-acid surfactants can be used to construct colloidal systems for delivering hydrophobic drugs or nutritions without lipids at human physiological pH level. PMID:27419647

  9. Cytotoxicity and cellular uptake of ZnS:Mn nanocrystals biofunctionalized with chitosan and aminoacids

    NASA Astrophysics Data System (ADS)

    Sajimol Augustine, M.; Anas, Abdulaziz; Das, Ani V.; Sreekanth, S.; Jayalekshmi, S.

    2015-02-01

    Highly luminescent, manganese doped, zinc sulphide (ZnS:Mn) nanocrystals biofunctionalized with chitosan and various aminoacids such as L-citrulline, L-lysine, L-arginine, L-serine, L-histidine and glycine were synthesized by chemical capping co-precipitation method at room temperature, which is a simple and cost effective technique. The synthesized nanocrystals were structurally characterized by TEM, XRD, EDXS and FT-IR spectroscopy techniques. They possess high colloidal stability with strong orange red photoluminescence emission at 598 nm. The intensity of orange red emission has been observed to be maximum in L-citrulline capped ZnS:Mn nanocrystals in which the emission at 420 nm is effectively quenched by surface passivation due to capping. Taking into consideration the prospects of these highly luminescent, bio-compatible ZnS:Mn nanocrystals in bio-imaging applications, cytotoxicity studies were conducted to identify the capping combination which would accomplish minimum toxic effects. ZnS:Mn nanocrystals biofunctionalized with chitosan, L-citrulline, glycine, L-artginine, L-serine and L-histidine showed least toxicity up to 10 nM concentrations in mouse fibroblast L929 cells, which further confirms their cytocompatibility. Also the ZnS:Mn nanocrystals biofunctionalized with L-arginine showed maximum uptake in in vitro studies carried out in human embryonic kidney cells, HEK-293T, which shows the significant role of this particular amino acid in fetoplacental nutrition. The present study highlights the suitability of aminoacid conjugated ZnS:Mn nanocrystals, as promising candidates for biomedical applications.

  10. An improved GRACE monthly gravity field solution by modeling the non-conservative acceleration and attitude observation errors

    NASA Astrophysics Data System (ADS)

    Chen, Qiujie; Shen, Yunzhong; Chen, Wu; Zhang, Xingfu; Hsu, Houze

    2016-02-01

    The main contribution of this study is to improve the GRACE gravity field solution by taking errors of non-conservative acceleration and attitude observations into account. Unlike previous studies, the errors of the attitude and non-conservative acceleration data, and gravity field parameters, as well as accelerometer biases are estimated by means of weighted least squares adjustment. Then we compute a new time series of monthly gravity field models complete to degree and order 60 covering the period Jan. 2003 to Dec. 2012 from the twin GRACE satellites' data. The derived GRACE solution (called Tongji-GRACE02) is compared in terms of geoid degree variances and temporal mass changes with the other GRACE solutions, namely CSR RL05, GFZ RL05a, and JPL RL05. The results show that (1) the global mass signals of Tongji-GRACE02 are generally consistent with those of CSR RL05, GFZ RL05a, and JPL RL05; (2) compared to CSR RL05, the noise of Tongji-GRACE02 is reduced by about 21 % over ocean when only using 300 km Gaussian smoothing, and 60 % or more over deserts (Australia, Kalahari, Karakum and Thar) without using Gaussian smoothing and decorrelation filtering; and (3) for all examples, the noise reductions are more significant than signal reductions, no matter whether smoothing and filtering are applied or not. The comparison with GLDAS data supports that the signals of Tongji-GRACE02 over St. Lawrence River basin are close to those from CSR RL05, GFZ RL05a and JPL RL05, while the GLDAS result shows the best agreement with the Tongji-GRACE02 result.

  11. An improved GRACE monthly gravity field solution by modeling the non-conservative acceleration and attitude observation errors

    NASA Astrophysics Data System (ADS)

    Chen, Qiujie; Shen, Yunzhong; Chen, Wu; Zhang, Xingfu; Hsu, Houze

    2016-06-01

    The main contribution of this study is to improve the GRACE gravity field solution by taking errors of non-conservative acceleration and attitude observations into account. Unlike previous studies, the errors of the attitude and non-conservative acceleration data, and gravity field parameters, as well as accelerometer biases are estimated by means of weighted least squares adjustment. Then we compute a new time series of monthly gravity field models complete to degree and order 60 covering the period Jan. 2003 to Dec. 2012 from the twin GRACE satellites' data. The derived GRACE solution (called Tongji-GRACE02) is compared in terms of geoid degree variances and temporal mass changes with the other GRACE solutions, namely CSR RL05, GFZ RL05a, and JPL RL05. The results show that (1) the global mass signals of Tongji-GRACE02 are generally consistent with those of CSR RL05, GFZ RL05a, and JPL RL05; (2) compared to CSR RL05, the noise of Tongji-GRACE02 is reduced by about 21 % over ocean when only using 300 km Gaussian smoothing, and 60 % or more over deserts (Australia, Kalahari, Karakum and Thar) without using Gaussian smoothing and decorrelation filtering; and (3) for all examples, the noise reductions are more significant than signal reductions, no matter whether smoothing and filtering are applied or not. The comparison with GLDAS data supports that the signals of Tongji-GRACE02 over St. Lawrence River basin are close to those from CSR RL05, GFZ RL05a and JPL RL05, while the GLDAS result shows the best agreement with the Tongji-GRACE02 result.

  12. Sensory Substitution

    NASA Astrophysics Data System (ADS)

    Verrillo, Ronald T.

    The idea that the cutaneous surface may be employed as a substitute for the eyes and ears is by no means a modern notion. Although the sense of touch has long been considered as a surrogate for both the visual and auditory modalities, the focus of this chapter will be on the efforts to develop a tactile substitute for hearing, especially that of human speech. The visual system is our primary means of processing information about environmental space such as orientation, distance, direction and size. It is much less effective in making temporal discriminations. The auditory system is unparalleled in processing information that involves rapid sequences of temporal events, such as speech and music. The tactile sense is capable of processing both spatial and temporal information although not as effective in either domain as the eye or the ear.

  13. Photochemical abiotic synthesis of amino-acid precursors from simulated planetary atmospheres by vacuum ultraviolet light

    SciTech Connect

    Takahashi, Jun-ichi; Masuda, Hitomi; Kaneko, Takeo; Kobayashi, Kensei; Saito, Takeshi; Hosokawa, Teruo

    2005-07-15

    For the purpose of investigating the photon energy dependence of the photoinduced abiotic synthesis of organic molecules, gas mixtures that simulate typical planetary atmospheres, including a carbon source (CO or CH{sub 4}), a nitrogen source (N{sub 2} or NH{sub 3}), and H{sub 2}O, were irradiated with synchrotron radiation through a vacuum-ultraviolet transmitting window. Three kinds of window material, fused silica, synthetic quartz, and MgF{sub 2}, were used as a high-energy-cutting filter, whose absorption-edge energies are 6.4, 8.1, and 10.5 eV, respectively. Three types of gas mixture, Titan-type (CH{sub 4}-N{sub 2}-H{sub 2}O), comet-type (CO-NH{sub 3}-H{sub 2}O), and primitive-Earth-type (CO-N{sub 2}-H{sub 2}O), were irradiated with vacuum-ultraviolet photons in the three energy ranges. After the irradiation, amino-acid formation yields in the acid-hydrolyzed solution of the product were measured with a high-performance liquid chromatograph method. From the Titan- and comet-type mixtures, amino acids were detected by irradiation with photons lower than 8.1 eV. For both mixtures, the averaged quantum yields of glycine generation in the photon energy region of 7-10.5 eV were of the order of 10{sup -5}, which was larger by about one order than that in the region 5-8 eV. On the other hand, from the primitive-Earth-type mixture, amino-acid formation was difficult to detect even with irradiation as high as 10.5 eV, even though amino acids were generated in comparable yields from the Titan- and comet-type mixtures by irradiation with soft x rays or proton beam, whose energies are much higher. These results suggest that the vacuum ultraviolet light is a more effective energy source for the generation of the precursors of bioorganic compounds in extraterrestrial environments than in primitive-Earth atmosphere.

  14. Photochemical abiotic synthesis of amino-acid precursors from simulated planetary atmospheres by vacuum ultraviolet light

    NASA Astrophysics Data System (ADS)

    Takahashi, Jun-Ichi; Masuda, Hitomi; Kaneko, Takeo; Kobayashi, Kensei; Saito, Takeshi; Hosokawa, Teruo

    2005-07-01

    For the purpose of investigating the photon energy dependence of the photoinduced abiotic synthesis of organic molecules, gas mixtures that simulate typical planetary atmospheres, including a carbon source (CO or CH4), a nitrogen source (N2 or NH3), and H2O, were irradiated with synchrotron radiation through a vacuum-ultraviolet transmitting window. Three kinds of window material, fused silica, synthetic quartz, and MgF2, were used as a high-energy-cutting filter, whose absorption-edge energies are 6.4, 8.1, and 10.5 eV, respectively. Three types of gas mixture, Titan-type (CH4-N2-H2O), comet-type (CO-NH3-H2O), and primitive-Earth-type (CO-N2-H2O), were irradiated with vacuum-ultraviolet photons in the three energy ranges. After the irradiation, amino-acid formation yields in the acid-hydrolyzed solution of the product were measured with a high-performance liquid chromatograph method. From the Titan- and comet-type mixtures, amino acids were detected by irradiation with photons lower than 8.1 eV. For both mixtures, the averaged quantum yields of glycine generation in the photon energy region of 7-10.5 eV were of the order of 10-5, which was larger by about one order than that in the region 5-8 eV. On the other hand, from the primitive-Earth-type mixture, amino-acid formation was difficult to detect even with irradiation as high as 10.5 eV, even though amino acids were generated in comparable yields from the Titan- and comet-type mixtures by irradiation with soft x rays or proton beam, whose energies are much higher. These results suggest that the vacuum ultraviolet light is a more effective energy source for the generation of the precursors of bioorganic compounds in extraterrestrial environments than in primitive-Earth atmosphere.

  15. Protein structure designability: The consequences of amino-acid alphabet and the underlying energy model

    NASA Astrophysics Data System (ADS)

    Buchler, Nicolas Emile G.

    2001-11-01

    It has been noted by scientists that certain native, protein structures occur more frequently than others in the Protein Data Bank. A variety of models have been developed to explain this phenomenon by considering protein structure "designability". A protein structure is more designable if a larger fraction of all possible sequences can fold into it. Such highly-designable structures are more likely to have been found and maintained through the process of evolution hence they are likely to be over-represented. Proteins are biopolymers and the key to designability lies with understanding the thermodynamic constraints of how a biologically relevant protein sequence folds into a native protein structure. We begin by discussing protein folding in the context of free energy landscapes and phase transitions. The role of protein evolution, critical transitions, such as "freezing" into the native state ( Tf), collapse into molten globules (Ttheta), and glassy phase transitions (Tg), folding-funnels, and free energy landscape measures is a well studied subject of protein folding both computationally and theoretically. In particular, the relationship between folding funnels and relevant phase transition temperatures (T f, Tg) can be related to free energy landscape measures, such as foldability F and energy gap Delta. Using the Random Energy Model, we analytically demonstrate the statistical relationship between F , Delta. Using simplified models of protein structure and interactions, we have explored the relationship between protein structure designability, foldability, interaction parameters, and amino-acid alphabet. We shed new light on which structures are expected to be highly designable, for which types of energy models (solvation or pair-contact), and why these structures are designable. Moreover, we can also understand why free energy landscape measures, such as foldability F and energy gap Delta, must be correlated to protein structure designability. We further

  16. Non-conservative characteristics of fluorescent tracers help to assess in-situ transport and attenuation of pesticides

    NASA Astrophysics Data System (ADS)

    Lange, Jens; Payraudeau, Sylvain; Imfeld, Gwenaël

    2016-04-01

    Traditionally, hydrological tracers are selected to behave as conservatively as possible, since most applications aim to investigate the transport of water or conservative solutes. Non-conservative tracer behavior is regarded as a limitation. However, the environmental behavior of organic pesticides is strictly non-conservative as their fate is affected by various processes, including sorption, photolysis and biochemical transformation in various environmental compartments. If tracers are used to study pesticides under these conditions, we believe that a paradigm shift is necessary: only a tracer that is affected by similar attenuation processes can realistically reproduce the overall behavior of a target pesticide. We present here two examples from two different environmental compartments: (i) agricultural soils and (ii) wetland systems. In both studies two organic fluorescent tracers (uranine, UR and sulforhodamine-B, SRB) and the salt tracer bromide (BR) were applied together with the chloroacetanilide herbicide S-metolachlor (S-MET). On an agricultural field, plot experiments were conducted under artificial and natural rainfall conditions. The use of BR overestimated both slow leaching and fast preferential transport of S-MET in the unsaturated zone, while UR/SRB were more realistic markers. Under artificial conditions, recovery rates of BR in a tile drain were twice as high as UR and one order of magnitude higher than SRB. Under natural conditions, BR concentrations in surface soils (0-1 cm) displayed larger variances during wetting and drying periods than UR, SRB and S-MET. BR also leached deeper (below 5 cm) than S-MET in the soil column. After 70 days, characteristic fluorescent peaks of UR and SRB gradually decreased in soil samples, while a new peak increased in another spectrum, which suggests the production of a potential transformation product. In two artificial wetland systems the impact of hydrological conditions (batch versus continuous-flow) on

  17. Evidence for non-conservative current-induced forces in the breaking of Au and Pt atomic chains

    PubMed Central

    Sabater, Carlos; Untiedt, Carlos

    2015-01-01

    Summary This experimental work aims at probing current-induced forces at the atomic scale. Specifically it addresses predictions in recent work regarding the appearance of run-away modes as a result of a combined effect of the non-conservative wind force and a ‘Berry force’. The systems we consider here are atomic chains of Au and Pt atoms, for which we investigate the distribution of break down voltage values. We observe two distinct modes of breaking for Au atomic chains. The breaking at high voltage appears to behave as expected for regular break down by thermal excitation due to Joule heating. However, there is a low-voltage breaking mode that has characteristics expected for the mechanism of current-induced forces. Although a full comparison would require more detailed information on the individual atomic configurations, the systems we consider are very similar to those considered in recent model calculations and the comparison between experiment and theory is very encouraging for the interpretation we propose. PMID:26734525

  18. Partitioning of amino-acid analogues in a five-slab membrane model

    SciTech Connect

    Sengupta, D; Smith, Jeremy C; Ullmann, G. Matthias

    2008-09-01

    The positional preferences of the twenty amino-acid residues in a phospholipid bilayer are investigated by calculating the solvation free energy of the corresponding side chain analogues using a five-slab continuum electrostatic model. The side-chain analogues of the aromatic residues tryptophan and tyrosine are found to partition in the head-group region, due to compensation between the increase of the non-polar component of the solvation free energy at the boundary with the aqueous region and the decrease in the electrostatic component. The side chain analogue of phenylalanine differs from the other aromatic molecules by being able to partition in both the head-group region and the membrane core. This finding is consistent with experimental findings of the position of phenylalanine in membrane helices. Interestingly, the charged side-chain analogues of arginine and lysine are shown to prefer the head-group region in an orientation that allows the charged moiety to interact with the aqueous layer. The orientation adopted is similar to the 'snorkelling' effect seen in lysine and arginine residues in membrane helices. In contrast, the preference of the charged side-chain analogues of histidine (protonated) and aspartate (deprotonated) for the aqueous layer is shown to be due to a steep decrease in the electrostatic component of the solvation free energy at the boundary to the aqueous region. The calculations allow an understanding of the origins of side chain positioning in membranes and are thus useful in understanding membrane-protein:lipid thermodynamics.

  19. Extended longevity and survivorship during amino-acid starvation in a Drosophila Sir2 mutant heterozygote.

    PubMed

    Slade, Jennifer D; Staveley, Brian E

    2016-05-01

    The regulation of energy homeostasis is pivotal to survive periods of inadequate nutrition. A combination of intricate pathways and proteins are responsible for maximizing longevity during such conditions. The sirtuin deacetylase Sir2 is well conserved from single-celled yeast to mammals, and it controls a number of downstream targets that are active during periods of extreme stress. Overexpression of Sir2 has been established to enhance survival of a number of model organisms undergoing calorie restriction, during which insulin receptor signalling (IRS) is reduced, a condition that itself can enhance survivorship during starvation. Increased Sir2 expression and reduced IRS result in an increase in the activity of the transcription factor foxo, an advantageous activation during stress but lethal when overly active. We have found that a lowered gene dosage of Sir2, in mutant heterozygotes, can extend normal longevity and greatly augment survivorship during amino-acid starvation in Drosophila. Additionally, these mutants, in either heterozygous or homozygous form, do not appear to have any disadvantageous effects upon development or cell growth of the organism unlike IRS mutants. These results may advance the understanding of the biological response to starvation and allow for the development of a model organism to mimic the ability of individuals to tolerate nutrient deprivation. PMID:27074822

  20. Substrate specificity and transport mechanism of amino-acid transceptor Slimfast from Aedes aegypti

    PubMed Central

    Boudko, Dmitri Y.; Tsujimoto, Hitoshi; Rodriguez, Stacy D.; Meleshkevitch, Ella A.; Price, David P.; Drake, Lisa L.; Hansen, Immo A.

    2015-01-01

    Anautogenous mosquitoes depend on vertebrate blood as nutrient source for their eggs. A highly efficient set of membrane transporters mediates the massive movement of nutrient amino acids between mosquito tissues after a blood meal. Here we report the characterization of the amino-acid transporter Slimfast (Slif) from the yellow-fever mosquito Aedes aegypti using codon-optimized heterologous expression. Slif is a well-known component of the target-of-rapamycin signalling pathway and fat body nutrient sensor, but its substrate specificity and transport mechanism were unknown. We found that Slif transports essential cationic and neutral amino acids with preference for arginine. It has an unusual dual-affinity mechanism with only the high affinity being Na+ dependent. Tissue-specific expression and blood meal-dependent regulation of Slif are consistent with conveyance of essential amino acids from gut to fat body. Slif represents a novel transport system and type of transceptor for sensing and transporting essential amino acids during mosquito reproduction. PMID:26449545

  1. Substrate specificity and transport mechanism of amino-acid transceptor Slimfast from Aedes aegypti.

    PubMed

    Boudko, Dmitri Y; Tsujimoto, Hitoshi; Rodriguez, Stacy D; Meleshkevitch, Ella A; Price, David P; Drake, Lisa L; Hansen, Immo A

    2015-01-01

    Anautogenous mosquitoes depend on vertebrate blood as nutrient source for their eggs. A highly efficient set of membrane transporters mediates the massive movement of nutrient amino acids between mosquito tissues after a blood meal. Here we report the characterization of the amino-acid transporter Slimfast (Slif) from the yellow-fever mosquito Aedes aegypti using codon-optimized heterologous expression. Slif is a well-known component of the target-of-rapamycin signalling pathway and fat body nutrient sensor, but its substrate specificity and transport mechanism were unknown. We found that Slif transports essential cationic and neutral amino acids with preference for arginine. It has an unusual dual-affinity mechanism with only the high affinity being Na(+) dependent. Tissue-specific expression and blood meal-dependent regulation of Slif are consistent with conveyance of essential amino acids from gut to fat body. Slif represents a novel transport system and type of transceptor for sensing and transporting essential amino acids during mosquito reproduction. PMID:26449545

  2. Structure and expression of the Drosophila ubiquitin-80-amino-acid fusion-protein gene.

    PubMed Central

    Barrio, R; del Arco, A; Cabrera, H L; Arribas, C

    1994-01-01

    In the fruitfly Drosophila, as in all eukaryotes examined so far, some ubiquitin-coding sequences appear fused to unrelated open reading frames. Two of these fusion genes have been previously described (the homologues of UBI1-UBI2 and UBI4 in yeast), and we report here the organization and expression of a third one, the DUb80 gene (the homologue of UBI3 in yeast). This gene encodes a ubiquitin monomer fused to an 80-amino-acid extension which is homologous with the ribosomal protein encoded by the UB13 gene. The 5' regulatory region of DUb80 shares common features with another ubiquitin fusion gene, DUb52, and with the ribosomal protein genes of Drosophila, Xenopus and mouse. We also find helix-loop-helix protein-binding sequences (E-boxes). The DUb80 gene is transcribed to a 0.9 kb mRNA which is particularly abundant under conditions of high protein synthesis, such as in ovaries and exponentially growing cells. Images Figure 3 Figure 4 PMID:8068011

  3. L-Aminoacid Oxidase from Bothrops leucurus Venom Induces Nephrotoxicity via Apoptosis and Necrosis

    PubMed Central

    Morais, Isabel C. O.; Pereira, Gustavo J. S.; Orzáez, M.; Jorge, Roberta J. B.; Bincoletto, Claudia; Toyama, Marcos H.; Monteiro, Helena S. A.; Smaili, Soraya S.; Pérez-Payá, Enrique; Martins, Alice M. C.

    2015-01-01

    Acute renal failure is a common complication caused by Bothrops viper envenomation. In this study, the nefrotoxicity of a main component of B. leucurus venom called L-aminoacid oxidase (LAAO-Bl) was evaluated by using tubular epithelial cell lines MDCK and HK-2 and perfused kidney from rats. LAAO-Bl exhibited cytotoxicity, inducing apoptosis and necrosis in MDCK and HK-2 cell lines in a concentration-dependent manner. MDCK apoptosis induction was accompanied by Ca2+ release from the endoplasmic reticulum, reactive oxygen species (ROS) generation and mitochondrial dysfunction with enhanced expression of Bax protein levels. LAAO-Bl induced caspase-3 and caspase-7 activation in both cell lines. LAAO-Bl (10 μg/mL) exerts significant effects on the isolated kidney perfusion increasing perfusion pressure and urinary flow and decreasing the glomerular filtration rate and sodium, potassium and chloride tubular transport. Taken together our results suggest that LAAO-Bl is responsible for the nephrotoxicity observed in the envenomation by snakebites. Moreover, the cytotoxic of LAAO-Bl to renal epithelial cells might be responsible, at least in part, for the nephrotoxicity observed in isolated kidney. PMID:26193352

  4. Multicultural Challenges in Educational Policies within a Non-Conservative Scenario: The Case of the Emerging Reforms in Higher Education in Brazil

    ERIC Educational Resources Information Center

    Canen, Ana

    2005-01-01

    The article discusses the extent to which multiculturalism has had an impact in the emerging reforms in higher education in Brazil, against the backdrop of the rise of a new non-Conservative, Labour-oriented government whose political agenda is marked by a discursive stand against conservatism, neo-liberalism and neocolonialism. Building on a…

  5. Vitreous Substitutes.

    PubMed

    Foster, William Joseph

    2008-04-01

    Modern vitreoretinal surgery is a young science. While tremendous developments have occurred in instrument design and technique since Machemer first described vitrectomy surgery in 1973[1], the application of advanced materials concepts to the development of intra-ocular compounds is a particularly exciting area of research. To date, the development of vitreous substitutes has played a significant role in enabling the dramatic and progressive improvement in surgical outcome, but perhaps no other area of research has the potential to further improve the treatment of retinal detachment and other retinal disorders. While prior research has focused solely upon the ability of a compound to re-attach the retina, future research should seek to enable the surgeon to inhibit the development of proliferative vitreoretinopathy and re-detachment, the integration of stem-cell therapies with surgical retina, long-term delivery of medications to the posterior segment, and the promotion of more rapid and complete visual rehabilitation. PMID:19343097

  6. Improving amino-acid identification, fit and C(alpha) prediction using the Simplex method in automated model building.

    PubMed

    Romo, Tod D; Sacchettini, James C; Ioerger, Thomas R

    2006-11-01

    Automated methods for protein model building in X-ray crystallography typically use a two-phased approach that involves first modeling the protein backbone followed by building in the side chains. The latter phase requires the identification of the amino-acid side-chain type as well as fitting of the side-chain model into the observed electron density. While mistakes in identification of individual side chains are common for a number of reasons, sequence alignment can sometimes be used to correct errors by mapping fragments into the true (expected) amino-acid sequence and exploiting contiguity constraints among neighbors. However, side chains cannot always be confidently aligned; this depends on having sufficient accuracy in the initial calls. The recognition of amino-acid side-chains based on the surrounding pattern of electron density, whether by features, density correlation or free atoms, can be sensitive to inaccuracies in the coordinates of the predicted backbone C(alpha) atoms to which they are anchored. By incorporating a Nelder-Mead Simplex search into the side-chain identification and model-building routines of TEXTAL, it is demonstrated that this form of residue-by-residue rigid-body real-space refinement (in which the C(alpha) itself is allowed to shift) can improve the initial accuracy of side-chain selection by over 25% on average (from 25% average identity to 32% on a test set of five representative proteins, without corrections by sequence alignment). This improvement in amino-acid selection accuracy in TEXTAL is often sufficient to bring the pairwise amino-acid identity of chains in the model out of the so-called ;twilight zone' for sequence-alignment methods. When coupled with sequence alignment, use of the Simplex search yielded improvements in side-chain accuracy on average by over 13 percentage points (from 64 to 77%) and up to 38 percentage points (from 40 to 78%) in one case compared with using sequence alignment alone. PMID:17057345

  7. [Adaptation to the availability of essential amino-acids: role of GCN2/eIF2α/ATF4 pathway].

    PubMed

    Fafournoux, Pierre; Averous, Julien; Bruhat, Alain; Carraro, Valérie; Jousse, Céline; Maurin, Anne-Catherine; Mesclon, Florent; Parry, Laurent

    2015-01-01

    In mammals, metabolic adaptations are required to overcome nutritional deprivation in amino-acids/proteins as well as episodes of malnutrition. GCN2 protein kinase, which phosphorylates the α subunit of the translation initiation factor eIF2, is a sensor of amino-acid(s) deficiencies. On one hand, this review briefly describes the main features of amino-acid metabolism. On the other hand, it describes the role of GCN2 in regulating numerous physiological functions. PMID:27021050

  8. Nucleophilic Aromatic Substitution.

    ERIC Educational Resources Information Center

    Avila, Walter B.; And Others

    1990-01-01

    Described is a microscale organic chemistry experiment which demonstrates one feasible route in preparing ortho-substituted benzoic acids and provides an example of nucleophilic aromatic substitution chemistry. Experimental procedures and instructor notes for this activity are provided. (CW)

  9. Synthesis and characterization of heteroleptic copper and zinc complexes with saccharinate and aminoacids. Evaluation of SOD-like activity of the copper complexes.

    PubMed

    Santi, Eduardo; Viera, Inés; Mombrú, Alvaro; Castiglioni, Jorge; Baran, Enrique J; Torre, María H

    2011-12-01

    Five new copper and zinc heteroleptic complexes with saccharin and aminoacids with general stoichiometry Na(2)[M(sac)(2)(aa)(2)].nH(2)O (M denotes Cu or Zn, sac the saccharinate ion, and aa the aminoacids) were synthesized and characterized by elemental and thermogravimetric analysis, conductimetric measurements and IR, Raman and UV-vis spectroscopies. In all the complexes, copper and zinc ions coordinated with the aminoacids through the terminal amine and carboxylate residues and with saccharin through the heterocyclic nitrogen atom. Besides, the superoxide dismutase-like activity of the heteroleptic copper complexes was evaluated and compared with the homoleptic copper amino acid complexes with the aim to observe the influence of the saccharin coordination. PMID:21336583

  10. Induced europium CPL for the selective signalling of phosphorylated amino-acids and O-phosphorylated hexapeptides.

    PubMed

    Neil, Emily R; Fox, Mark A; Pal, Robert; Parker, David

    2016-05-17

    Two bright, europium(iii) complexes based on an achiral heptadentate triazacyclononane ligand bearing two strongly absorbing chromophores have been evaluated for the selective emission and CPL signalling of various chiral O-phosphono-anions. Binding of O-phosphono-Ser and Thr gives rise to a strong induced CPL signature and a favoured Δ complex configuration is adopted. A similarly large induced CPL signal arises when [Eu·](2+) binds to lysophosphatidic acid (LPA), where the strong binding (log K 5.25 (295 K)) in methanol allowed its detection over the range 5 to 40 μM. Strong and chemoselective binding to the phosphorylated amino-acid residues was also observed with a set of four structurally related hexapeptides: in one case, the sign of the gem value in the ΔJ = 1 transition allowed differentiation between the binding to O-P-Ser and O-P-Tyr residues. PMID:27109001

  11. The delta EEG (sleep)-inducing peptide (DSIP). XI. Amino-acid analysis, sequence, synthesis and activity of the nonapeptide.

    PubMed

    Schoenenberger, G A; Maier, P F; Tobler, H J; Wilson, K; Monnier, M

    1978-09-01

    A peptide which induces slow-wave EEG (sleep) after intraventricular infusion into the brain has been isolated from the extracorporeal dialysate of cerebral venous blood in rabbits submitted to hypnogenic electrical stimulation of the intralaminar thalamic area. It was shown by amino-acid analysis and sequence determination to be Trp-Ala-Gly-Gly-Asp-Ala-Ser-Gly-Glu and named "Delta Sleep-Inducing Peptide" (DSIP). This compound was synthesized as well as 5 possible metabolic products (1--8, 2--9, 2--8, 1--4 and 5--9), 2 nonapeptide analogues (with one and two amino-acids exchanged) and a related tripeptide (Trp-Ser-Glu). All 9 synthetic peptides were infused intraventricularly in rabbits (6 nmol/kg in 0.05 ml of CSF-like solution over 3.5 min) and tested under double-blind conditions. A total of 61 rabbits including controls were used. The EEG from the frontal neocortex and the limbic archicortex were subjected to direct fast-Fourier transformation and analyzed by an 1108 computer system. A highly specific delta and spindle EEG-enhancing effect of the synthetic DSIP could be demonstrated. The mean increase of EEG delta activity reached 35% in the neocortex and limbic cortex as compared to control animals receiving CSF-like solution or any of the other 8 peptides. The final chemical characterization of the synthetic DSIP revealed that only the pure alpha-aspartyl peptide is highly active in contrast to its beta-Asp isomer. A neurohumoral modulating and programming activity was suggested. PMID:568769

  12. Amino-acid uptake by mussels, Mytilus edulis, from natural sea water in a flow-through system

    NASA Astrophysics Data System (ADS)

    Siebers, D.; Winkler, A.

    1984-03-01

    Natural Wadden Sea water taken from the North Sea (island of Sylt) was pumped at rates of 150 and 300 l h-1 through a 4 l plexiglass tube mounted on a wooden tripod on the beach. The tube was densely filled with numerous cleaned mussels, Mytilus edulis. HPLC analysis of sea water showed that total dissolved amino acids are patchily distributed, varying by 100 % within 15 min, though proportions of individual amino acids were remarkably constant. Total amino-acid concentrations were 1528±669 nM (N=3) in October 1983 and 1198±597 nM (N=7) in July 1984. Samples taken at the entrance and the outlet of the experimental mussel bed revealed that the mussels had taken up 29 to 66 % of the amino acids dissolved in sea water. Uptake was observed for all amino acids detected in the chromatograms. 78 % of uptake resulted from the 5 most concentrated amino acids: serine, alanine, glycine/threonine, ornithine, aspartic acid. The nutritional profit obtained from uptake of dissolved amino acids amounted to 12 % (N=5, range 5 23 %, flow rate 150 l h-1) and to 24 % (N=3, range 13 38 %, flow rate 300 l h-1) of metabolic rate. The present data suggest that amino-acid concentration predominantly determines the magnitude of the nutritional profit obtained from uptake, and to a smaller extent the flow rate. These findings are in contrast to results of previous studies on Asterias rubens, interacting in small-volume closed systems with the natural bacterial sea water flora (Siebers, 1982). In these experiments, bacteria, due to rapid uptake, outcompeted the sea stars in absorption of dissolved amino acids. The present results suggest that bivalve mussels, can, due to their large gill surface areas and the great amounts of water pumped through their mantle cavity, successfully compete with bacteria in uptake of dissolved organic matter. Mussels, therefore, suggestedly play an important role in cycling dissolved organic matter.

  13. 40 CFR 721.8780 - Substituted pyridine azo substituted phenyl.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Substituted pyridine azo substituted... Specific Chemical Substances § 721.8780 Substituted pyridine azo substituted phenyl. (a) Chemical substance... substituted pyridine azo substituted phenyl (PMNs P-96-767 and P-96-773) are subject to reporting under...

  14. 40 CFR 721.8780 - Substituted pyridine azo substituted phenyl.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Substituted pyridine azo substituted... Specific Chemical Substances § 721.8780 Substituted pyridine azo substituted phenyl. (a) Chemical substance... substituted pyridine azo substituted phenyl (PMNs P-96-767 and P-96-773) are subject to reporting under...

  15. 40 CFR 721.8780 - Substituted pyridine azo substituted phenyl.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Substituted pyridine azo substituted... Specific Chemical Substances § 721.8780 Substituted pyridine azo substituted phenyl. (a) Chemical substance... substituted pyridine azo substituted phenyl (PMNs P-96-767 and P-96-773) are subject to reporting under...

  16. 40 CFR 721.8780 - Substituted pyridine azo substituted phenyl.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Substituted pyridine azo substituted... Specific Chemical Substances § 721.8780 Substituted pyridine azo substituted phenyl. (a) Chemical substance... substituted pyridine azo substituted phenyl (PMNs P-96-767 and P-96-773) are subject to reporting under...

  17. 40 CFR 721.8780 - Substituted pyridine azo substituted phenyl.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Substituted pyridine azo substituted... Specific Chemical Substances § 721.8780 Substituted pyridine azo substituted phenyl. (a) Chemical substance... substituted pyridine azo substituted phenyl (PMNs P-96-767 and P-96-773) are subject to reporting under...

  18. Theory of Metastable State Relaxation in a Gravitational Field for Non-Critical Binary Systems with Non-Conserved Order Parameter

    NASA Technical Reports Server (NTRS)

    Izmailov, Alexander F.; Myerson, Allan S.

    1993-01-01

    A new mathematical ansatz is developed for solution of the time-dependent Ginzburg-Landau nonlinear partial differential equation describing metastable state relaxation in binary (solute+solvent) non-critical solutions with non-conserved scalar order parameter in presence of a gravitational field. It has been demonstrated analytically that in such systems metastability initiates heterogeneous solute redistribution which results in the formation of a non-equilibrium singly-periodic spatial solute structure in the new solute-rich phase. The critical radius of nucleation and the induction time in these systems are gravity-dependent. It has also been proved that metastable state relaxation in vertical columns of supersaturated non-critical binary solutions leads to formation of the solute concentration gradient. Analytical expression for this concentration gradient is found and analysed. It is concluded that gravity can initiate phase separation (nucleation or spinodal decomposition).

  19. Managing Substitute Teaching.

    ERIC Educational Resources Information Center

    Jones, Kevin R.

    1999-01-01

    This news brief presents information on managing substitute teaching. The information is based on issues discussed at a summit meeting which included public school administrators and personnel directors from around the nation. The main topics of concern focused around four core components related to the management of substitute teaching:…

  20. Apple Aminoacid Profile and Yeast Strains in the Formation of Fusel Alcohols and Esters in Cider Production.

    PubMed

    Eleutério Dos Santos, Caroline Mongruel; Pietrowski, Giovana de Arruda Moura; Braga, Cíntia Maia; Rossi, Márcio José; Ninow, Jorge; Machado Dos Santos, Tâmisa Pires; Wosiacki, Gilvan; Jorge, Regina Maria Matos; Nogueira, Alessandro

    2015-06-01

    The amino acid profile in dessert apple must and its effect on the synthesis of fusel alcohols and esters in cider were established by instrumental analysis. The amino acid profile was performed in nine apple musts. Two apple musts with high (>150 mg/L) and low (<75 mg/L) nitrogen content, and four enological yeast strains, were used in cider fermentation. The aspartic acid, asparagine and glutamic acid amino acids were the majority in all the apple juices, representing 57.10% to 81.95%. These three amino acids provided a high consumption (>90%) during fermentation in all the ciders. Principal component analysis (PCA) explained 81.42% of data variability and the separation of three groups for the analyzed samples was verified. The ciders manufactured with low nitrogen content showed sluggish fermentation and around 50% less content of volatile compounds (independent of the yeast strain used), which were mainly 3-methyl-1-butanol (isoamyl alcohol) and esters. However, in the presence of amino acids (asparagine, aspartic acid, glutamic acid and alanine) there was a greater differentiation between the yeasts in the production of fusel alcohols and ethyl esters. High contents of these aminoacids in dessert apple musts are essential for the production of fusel alcohols and most of esters by aromatic yeasts during cider fermentation. PMID:25920613

  1. 40 CFR 721.981 - Substituted naphtholoazo-substituted naphthalenyl-substituted azonaphthol chromium complex.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... naphthalenyl-substituted azonaphthol chromium complex. 721.981 Section 721.981 Protection of Environment...-substituted naphthalenyl-substituted azonaphthol chromium complex. (a) Chemical substance and significant new... naphtholoazo-substituted naphthalenyl-substituted azonaphthol chromium complex (PMN P-93-1631) is subject...

  2. 40 CFR 721.981 - Substituted naphtholoazo-substituted naphthalenyl-substituted azonaphthol chromium complex.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... naphthalenyl-substituted azonaphthol chromium complex. 721.981 Section 721.981 Protection of Environment...-substituted naphthalenyl-substituted azonaphthol chromium complex. (a) Chemical substance and significant new... naphtholoazo-substituted naphthalenyl-substituted azonaphthol chromium complex (PMN P-93-1631) is subject...

  3. 40 CFR 721.981 - Substituted naphtholoazo-substituted naphthalenyl-substituted azonaphthol chromium complex.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... naphthalenyl-substituted azonaphthol chromium complex. 721.981 Section 721.981 Protection of Environment...-substituted naphthalenyl-substituted azonaphthol chromium complex. (a) Chemical substance and significant new... naphtholoazo-substituted naphthalenyl-substituted azonaphthol chromium complex (PMN P-93-1631) is subject...

  4. 40 CFR 721.981 - Substituted naphtholoazo-substituted naphthalenyl-substituted azonaphthol chromium complex.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... naphthalenyl-substituted azonaphthol chromium complex. 721.981 Section 721.981 Protection of Environment...-substituted naphthalenyl-substituted azonaphthol chromium complex. (a) Chemical substance and significant new... naphtholoazo-substituted naphthalenyl-substituted azonaphthol chromium complex (PMN P-93-1631) is subject...

  5. 40 CFR 721.981 - Substituted naphtholoazo-substituted naphthalenyl-substituted azonaphthol chromium complex.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... naphthalenyl-substituted azonaphthol chromium complex. 721.981 Section 721.981 Protection of Environment...-substituted naphthalenyl-substituted azonaphthol chromium complex. (a) Chemical substance and significant new... naphtholoazo-substituted naphthalenyl-substituted azonaphthol chromium complex (PMN P-93-1631) is subject...

  6. Co-occurrence of analogous enzymes determines evolution of a novel (βα)8-isomerase sub-family after non-conserved mutations in flexible loop.

    PubMed

    Verduzco-Castro, Ernesto A; Michalska, Karolina; Endres, Michael; Juárez-Vazquez, Ana L; Noda-García, Lianet; Chang, Changsoo; Henry, Christopher S; Babnigg, Gyorgy; Joachimiak, Andrzej; Barona-Gómez, Francisco

    2016-05-01

    We investigate the evolution of co-occurring analogous enzymes involved in L-tryptophan and L-histidine biosynthesis in Actinobacteria Phylogenetic analysis of trpF homologues, a missing gene in certain clades of this lineage whose absence is complemented by a dual-substrate HisA homologue, termed PriA, found that they fall into three categories: (i) trpF-1, an L-tryptophan biosynthetic gene horizontally acquired by certain Corynebacterium species; (ii) trpF-2, a paralogue known to be involved in synthesizing a pyrrolopyrrole moiety and (iii) trpF-3, a variable non-conserved orthologue of trpF-1 We previously investigated the effect of trpF-1 upon the evolution of PriA substrate specificity, but nothing is known about the relationship between trpF-3 and priA After in vitro steady-state enzyme kinetics we found that trpF-3 encodes a phosphoribosyl anthranilate isomerase. However, mutation of this gene in Streptomyces sviceus did not lead to auxothrophy, as expected from the biosynthetic role of trpF-1 Biochemical characterization of a dozen co-occurring TrpF-2 or TrpF-3, with PriA homologues, explained the prototrophic phenotype, and unveiled an enzyme activity trade-off between TrpF and PriA. X-ray structural analysis suggests that the function of these PriA homologues is mediated by non-conserved mutations in the flexible L5 loop, which may be responsible for different substrate affinities. Thus, the PriA homologues that co-occur with TrpF-3 represent a novel enzyme family, termed PriB, which evolved in response to PRA isomerase activity. The characterization of co-occurring enzymes provides insights into the influence of functional redundancy on the evolution of enzyme function, which could be useful for enzyme functional annotation. PMID:26929404

  7. A direct Arbitrary-Lagrangian-Eulerian ADER-WENO finite volume scheme on unstructured tetrahedral meshes for conservative and non-conservative hyperbolic systems in 3D

    NASA Astrophysics Data System (ADS)

    Boscheri, Walter; Dumbser, Michael

    2014-10-01

    In this paper we present a new family of high order accurate Arbitrary-Lagrangian-Eulerian (ALE) one-step ADER-WENO finite volume schemes for the solution of nonlinear systems of conservative and non-conservative hyperbolic partial differential equations with stiff source terms on moving tetrahedral meshes in three space dimensions. A WENO reconstruction technique is used to achieve high order of accuracy in space, while an element-local space-time Discontinuous Galerkin finite element predictor on moving curved meshes is used to obtain a high order accurate one-step time discretization. Within the space-time predictor the physical element is mapped onto a reference element using a high order isoparametric approach, where the space-time basis and test functions are given by the Lagrange interpolation polynomials passing through a predefined set of space-time nodes. Since our algorithm is cell-centered, the final mesh motion is computed by using a suitable node solver algorithm. A rezoning step as well as a flattener strategy are used in some of the test problems to avoid mesh tangling or excessive element deformations that may occur when the computation involves strong shocks or shear waves. The ALE algorithm presented in this article belongs to the so-called direct ALE methods because the final Lagrangian finite volume scheme is based directly on a space-time conservation formulation of the governing PDE system, with the rezoned geometry taken already into account during the computation of the fluxes. We apply our new high order unstructured ALE schemes to the 3D Euler equations of compressible gas dynamics, for which a set of classical numerical test problems has been solved and for which convergence rates up to sixth order of accuracy in space and time have been obtained. We furthermore consider the equations of classical ideal magnetohydrodynamics (MHD) as well as the non-conservative seven-equation Baer-Nunziato model of compressible multi-phase flows with

  8. Sugar substitutes during pregnancy

    PubMed Central

    Pope, Eliza; Koren, Gideon; Bozzo, Pina

    2014-01-01

    Abstract Question I have a pregnant patient who regularly consumes sugar substitutes and she asked me if continuing their use would affect her pregnancy or child. What should I tell her, and are there certain options that are better for use during pregnancy? Answer Although more research is required to fully determine the effects of in utero exposure to sugar substitutes, the available data do not suggest adverse effects in pregnancy. However, it is recommended that sugar substitutes be consumed in moderate amounts, adhering to the acceptable daily intake standards set by regulatory agencies. PMID:25392440

  9. The 30-Amino-Acid Deletion in the Nsp2 of Highly Pathogenic Porcine Reproductive and Respiratory Syndrome Virus Emerging in China Is Not Related to Its Virulence▿

    PubMed Central

    Zhou, Lei; Zhang, Jialong; Zeng, Jingwen; Yin, Shuoyan; Li, Yanhua; Zheng, Linying; Guo, Xin; Ge, Xinna; Yang, Hanchun

    2009-01-01

    During the past 2 years, an atypical clinical outbreak, caused by a highly pathogenic porcine reproductive and respiratory syndrome virus (PRRSV) with a unique 30-amino-acid deletion in its Nsp2-coding region, was pandemic in China. In this study, we generated four full-length infectious cDNA clones: a clone of the highly virulent PRRSV strain JXwn06 (pWSK-JXwn), a clone of the low-virulence PRRSV strain HB-1/3.9 (pWSK-HB-1/3.9), a chimeric clone in which the Nsp2 region containing the 30-amino-acid deletion was replaced by the corresponding region of the low-virulence PRRSV strain HB-1/3.9 (pWSK-JXwn-HB1nsp2), and a mutated HB-1/3.9 clone with the same deletion in Nsp2 as JXwn06 (pWSK-HB1-ND30). We also investigated the pathogenicities of the rescued viruses (designated RvJXwn, RvJXwn-HB1nsp2, RvHB-1/3.9, and RvHB1-ND30, respectively) in specific-pathogen-free piglets in order to determine the role of the 30-amino-acid deletion in the virulence of the highly pathogenic PRRSV. All the rescued viruses could replicate stably in MARC-145 cells. Our findings indicated that RvJXwn-HB1nsp2 retained high virulence for piglets, like RvJXwn and the parental virus JXwn06, although the survival time of piglets infected with RvJXwn-HB1nsp2 was obviously prolonged. RvHB1-ND30 exhibited low virulence for piglets, like RvHB-1/3.9 and the parental virus HB-1/3.9. Therefore, we conclude that the 30-amino-acid deletion is not related to the virulence of the highly pathogenic PRRSV emerging in China. PMID:19244318

  10. Response of Fe-S cluster assembly machinery of Escherichia coli to mechanical stress in a model of amino-acid crystal fermentation.

    PubMed

    Okutani, Satoshi; Iwai, Takayoshi; Iwatani, Shintaro; Matsuno, Kiyoshi; Takahashi, Yasuhiro; Hase, Toshiharu

    2015-09-01

    During amino-acid crystal fermentation, mechanical stress on bacterial cells caused by crystal collision often impacts negatively on bacterial growth and amino-acid production. When Escherichia coli cells were cultivated under mechanical stress of polyvinyl chloride particles as a model of the crystal fermentation, activities of iron-sulfur (Fe-S) cluster-containing enzymes were apparently decreased. Based on an assumption that function of Fe-S cluster assembly machinery would be elevated to recover the enzyme activities in such stressed cells, we analyzed levels of various components of Fe-S cluster assembly machinery by western blotting. It was found that the expression of HscA, a chaperon component of the machinery, was up-regulated and that shorter forms of HscA with the N-terminal region truncated were accumulated, suggesting an important role of HscA against the mechanical stress. An overexpression of HscA gene in E. coli cells gave a positive effect on rescue of the stress-induced decrease of the activity of Fe-S cluster-containing enzyme. These results may provide a new strategy to alleviate the mechanical stress during the amino-acid crystal fermentation. PMID:25682519

  11. A New Pro-Prodrug Aminoacid-Based for Trans-Ferulic Acid and Silybin Intestinal Release

    PubMed Central

    Trombino, Sonia; Ferrarelli, Teresa; Cassano, Roberta

    2014-01-01

    The aim of this work was the preparation and characterization of a pro-prodrug able to simultaneously transport silybin, a drug possessing various pharmacological effects, and trans-ferulic acid, a known antioxidant. More specifically, l-phenylalanine-N-(4-hydroxy-3-methoxy-phenyl) prop-2-en-O-(2R,3R)-3,5,7-trihydroxy-2-((2R,3R)-3-(4-hydroxy-3-methoxyphenyl)-2-(hydroxymethyl)-2,3-dihydro-benzo-(1,4)-dioxin-6-yl)croman-4-one was synthesized by using the aminoacid l-phenylalanine (l-Phe) as carrier. Indeed, l-Phe is characterized by an intrinsic chemical reactivity due to the presence of an amino group, placed on the chiral center, and of a carboxylic group. The synthesis has been characterized first by adding silybin by means of carboxylic group and then, with the aim to confer antioxidant properties to this new carrier, by linking trans-ferulic acid to l-Phe via amino group. The so obtained derivative was then characterized by FT-IR, and 1H-NMR spectroscopies. Furthermore, its ability to inhibit lipid peroxidation induced by tert-butyl hydroperoxide in rat liver microsomes, was evaluated. The 1,1-diphenyl-2-picrylhydrazyl radical-scavenging effect, was also assessed. The release of silybin and trans-ferulic acid was determined in simulated gastric and intestinal fluids over the time. The results showed that the covalent bond between both (i) silybin; or (ii) trans-ferulic acid and the amino acid was degraded by enzymatic reactions. In addition, the pro-prodrug, showed strong antioxidant and scavenger activities. Due to these properties, this new pro-prodrug could be applied for the treatment of intestinal pathologies and it might improve the therapeutic potential of silybin which is strongly limited by its low solubility. PMID:25062426

  12. Plasma secretin concentration in anaesthetized pigs after intraduodenal glucose, fat, aminoacids, or meals with various pH.

    PubMed

    Fahrenkrug, J; Schaffalitzky de Muckadell, O B; Holst, J J

    1977-01-01

    The concentration of immunoreactive secretin in portal blood and the secretion from the exocrine pancreas were measured during intraduodenal infusion of isotonic or hypertonic saline, isotonic or hypertonic glucose, aminoacids, fat emulsion, or 0.1 mol X 1(-1) hydrochloric acid in 7 anaesthetized pigs. None of these substances, except hydrochloric acid, had any effect on plasma secretin concentration and pancreatic flow rate and bicarbonate output. Plasma secretin concentration rose significantly from 5.6 +/- 2.7 pmol X 1(-1) (mean +/- S.E.M.) to a peak value of 201.2 +/- 80.5 pmol X 1(-1) 15 min after infusion of hydrochloric acid. Pancreatic flow rate and bicarbonate output increased from 0.51 +/- 0.19 ml X h-1 (mean +/- S.E.M.) to 9.85 +/- 2.33 ml X h-1 and from 52 +/- 11 micronmol X h-1 to 1.004 +/- 290 micronmol X h-1, respectively. During intraduodenal introduction of meals with pH adjusted from 1.0 to 7.0 in 4 pigs amylase was secreted at all pH levels. However, only when pH of the meal was 1.0, resulting in an intraduodenal pH from 1.0 to 1.7 during the stimulation, was a significant increase in plasma secretin concentration and pancreatic flow rate observed from 5.5 +/- 2.8 pmol X 1(-1) (mean +/- S.E.M.) to 115.0 +/- 51.2 pmol X 1(-1) and from 0.20 +/- 0.08 ml X h-1 to 6.25 +/- 2.57 ml X h-1, respectively. PMID:17153

  13. Measurement scheme for a ground-state parity non-conserving (PNC) measurement in a cesium atomic beam via two-pathway coherent control

    NASA Astrophysics Data System (ADS)

    Choi, Jungu; Elliott, Dan; Elliott's Lab Team

    2016-05-01

    We present a detailed analysis of an experimental setup for parity non-conserving (PNC) measurements in a cesium atomic beam. We employ a parallel-plate transmission line (PPTL) structure and highly reflective cylindrical mirrors to form a microwave cavity resonator to excite the PNC transitions in the cesium hyperfine ground states. In addition, a variable external dc field is applied to observe the Stark-induced transition, which would interfere with the PNC transition as the dc field amplitude changes. Finally, strong Raman lasers are used to excite the ground hyperfine transition. The Raman fields interfere with the weak transitions, and by varying the phase difference between the Raman fields and the microwave fields, we would infer the weak transition amplitudes from the signal modulation. The experimental setup requires maintaining coherent phase relations between all fields, well-characterized dc and rf field patterns, the two co-propagating Raman lasers, and suppression of the magnetic dipole contribution. Our analysis of the field modes supported by the PPTL structure indicates that with a moderate rf power and a few tens of seconds of data collection time, the PNC measurement of less than 3% uncertainty would be feasible.

  14. Well-balanced high-order centred schemes for non-conservative hyperbolic systems. Applications to shallow water equations with fixed and mobile bed

    NASA Astrophysics Data System (ADS)

    Canestrelli, Alberto; Siviglia, Annunziato; Dumbser, Michael; Toro, Eleuterio F.

    2009-06-01

    This paper concerns the development of high-order accurate centred schemes for the numerical solution of one-dimensional hyperbolic systems containing non-conservative products and source terms. Combining the PRICE-T method developed in [Toro E, Siviglia A. PRICE: primitive centred schemes for hyperbolic system of equations. Int J Numer Methods Fluids 2003;42:1263-91] with the theoretical insights gained by the recently developed path-conservative schemes [Castro M, Gallardo J, Parés C. High-order finite volume schemes based on reconstruction of states for solving hyperbolic systems with nonconservative products applications to shallow-water systems. Math Comput 2006;75:1103-34; Parés C. Numerical methods for nonconservative hyperbolic systems: a theoretical framework. SIAM J Numer Anal 2006;44:300-21], we propose the new PRICE-C scheme that automatically reduces to a modified conservative FORCE scheme if the underlying PDE system is a conservation law. The resulting first-order accurate centred method is then extended to high order of accuracy in space and time via the ADER approach together with a WENO reconstruction technique. The well-balanced properties of the PRICE-C method are investigated for the shallow water equations. Finally, we apply the new scheme to the shallow water equations with fix bottom topography and with variable bottom solving an additional sediment transport equation.

  15. Substitution of anticonvulsant drugs

    PubMed Central

    Steinhoff, Bernhard J; Runge, Uwe; Witte, Otto W; Stefan, Hermann; Hufnagel, Andreas; Mayer, Thomas; Krämer, Günter

    2009-01-01

    Changing from branded drugs to generic alternatives, or between different generic formulations, is common practice aiming at reducing health care costs. It has been suggested that antiepileptic drugs (AEDs) should be exempt from substitution because of the potential negative consequences of adverse events and breakthrough seizures. Controlled data are lacking on the risk of substitution. However, retrospective data from large medical claims databases suggest that switching might be associated with increased use of AED and non-AED medications, and health care resources (including hospitalization). In addition, some anecdotal evidence from patients and health care providers’ surveys suggest a potentially negative impact of substitution. Well-controlled data are needed to assess the real risk associated with substitution, allowing health care professionals involved in the care of patients with epilepsy to make informed decisions. This paper reviews currently available literature, based on which the authors suggest that the decision to substitute should be made on an individual basis by the physician and an informed patient. Unendorsed or undisclosed substitution at the pharmacy level should be discouraged. PMID:19707254

  16. The substitutability of reinforcers

    PubMed Central

    Green, Leonard; Freed, Debra E.

    1993-01-01

    Substitutability is a construct borrowed from microeconomics that describes a continuum of possible interactions among the reinforcers in a given situation. Highly substitutable reinforcers, which occupy one end of the continuum, are readily traded for each other due to their functional similarity. Complementary reinforcers, at the other end of the continuum, tend to be consumed jointly in fairly rigid proportion, and therefore cannot be traded for one another except to achieve that proportion. At the center of the continuum are reinforcers that are independent with respect to each other; consumption of one has no influence on consumption of another. Psychological research and analyses in terms of substitutability employ standard operant conditioning paradigms in which humans and nonhumans choose between alternative reinforcers. The range of reinforcer interactions found in these studies is more readily accommodated and predicted when behavior-analytic models of choice consider issues of substitutability. New insights are gained into such areas as eating and drinking, electrical brain stimulation, temporal separation of choice alternatives, behavior therapy, drug use, and addictions. Moreover, the generalized matching law (Baum, 1974) gains greater explanatory power and comprehensiveness when measures of substitutability are included. PMID:16812696

  17. The substitutability of reinforcers.

    PubMed

    Green, Leonard; Freed, Debra E

    1993-07-01

    Substitutability is a construct borrowed from microeconomics that describes a continuum of possible interactions among the reinforcers in a given situation. Highly substitutable reinforcers, which occupy one end of the continuum, are readily traded for each other due to their functional similarity. Complementary reinforcers, at the other end of the continuum, tend to be consumed jointly in fairly rigid proportion, and therefore cannot be traded for one another except to achieve that proportion. At the center of the continuum are reinforcers that are independent with respect to each other; consumption of one has no influence on consumption of another. Psychological research and analyses in terms of substitutability employ standard operant conditioning paradigms in which humans and nonhumans choose between alternative reinforcers. The range of reinforcer interactions found in these studies is more readily accommodated and predicted when behavior-analytic models of choice consider issues of substitutability. New insights are gained into such areas as eating and drinking, electrical brain stimulation, temporal separation of choice alternatives, behavior therapy, drug use, and addictions. Moreover, the generalized matching law (Baum, 1974) gains greater explanatory power and comprehensiveness when measures of substitutability are included. PMID:16812696

  18. [Substitution therapy with diamorphine].

    PubMed

    Roy, Mandy; Bleich, Stefan; Hillemacher, Thomas

    2016-03-01

    After a long lead time the substitution with diamorphine was taken into the German catalogue of statutory health insurance in 2010. Currently about 570 patients are treated this way in 9 ambulances in Germany. The study phase as well as the clinical practice are showing the success of this therapy concerning physical and mental health of patients and their circumstances of social life. Thereby substitution with diamorphine is underlying very strict admission criteria regarding patients on the one hand and particular organizational requirements of the medical institution on the other hand. This article explains these criteria in detail as well as neurobiological information and clinical workflow is presented. Improvement of mandatory requirements could lead to a better reaching of patients who benefit from substitution with diamorphine. PMID:27029045

  19. Aryl substitution of pentacenes

    PubMed Central

    Waterloo, Andreas R; Sale, Anna-Chiara; Lehnherr, Dan; Hampel, Frank

    2014-01-01

    Summary A series of 11 new pentacene derivatives has been synthesized, with unsymmetrical substitution based on a trialkylsilylethynyl group at the 6-position and various aryl groups appended to the 13-position. The electronic and physical properties of the new pentacene chromophores have been analyzed by UV–vis spectroscopy (solution and thin films), thermoanalytical methods (DSC and TGA), cyclic voltammetry, as well as X-ray crystallography (for 8 derivatives). X-ray crystallography has been specifically used to study the influence of unsymmetrical substitution on the solid-state packing of the pentacene derivatives. The obtained results add to our ability to better predict substitution patterns that might be helpful for designing new semiconductors for use in solid-state devices. PMID:25161729

  20. [Delegation yes, substitution no!].

    PubMed

    Schroeder, A

    2014-08-01

    The aging of society leads on the one hand to increasing case numbers and on the other hand to a reduction in the number of physicians available for patient treatment. The delegation and substitution of medical duties as a tried and tested method is increasingly being recommended in order to compensate for the lack of physicians. The Berufsverband der Deutschen Urologen (BDU, Professional Association of German Urologists) supports the guiding principle of the Bundesärztekammer (Federal Medical Council) of "delegation yes, substitution no" and rejects a substitution of medical duties by non-medical academic health personnel. Against the background of the demographic changes, the increasing need for treatment and the current deficiency of junior physicians, a more extensive inclusion of well-qualified and experienced non-medical personnel by the delegation of medically responsible duties (medical scope of practice) can be an appropriate measure to maintain a good medical service in practices, hospitals and nursing homes. PMID:25047595

  1. 40 CFR 721.6920 - Butyl acrylate, polymer with substituted methyl styrene, methyl methacrylate, and substituted...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... substituted methyl styrene, methyl methacrylate, and substituted silane. 721.6920 Section 721.6920 Protection... acrylate, polymer with substituted methyl styrene, methyl methacrylate, and substituted silane. (a... butyl acrylate, polymer with substituted methyl styrene, methyl methacrylate, and substituted...

  2. 40 CFR 721.6920 - Butyl acrylate, polymer with substituted methyl styrene, methyl methacrylate, and substituted...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... substituted methyl styrene, methyl methacrylate, and substituted silane. 721.6920 Section 721.6920 Protection... acrylate, polymer with substituted methyl styrene, methyl methacrylate, and substituted silane. (a... butyl acrylate, polymer with substituted methyl styrene, methyl methacrylate, and substituted...

  3. 40 CFR 721.6920 - Butyl acrylate, polymer with substituted methyl styrene, methyl methacrylate, and substituted...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... substituted methyl styrene, methyl methacrylate, and substituted silane. 721.6920 Section 721.6920 Protection... acrylate, polymer with substituted methyl styrene, methyl methacrylate, and substituted silane. (a... butyl acrylate, polymer with substituted methyl styrene, methyl methacrylate, and substituted...

  4. Narcotic antagonists in drug dependence: pilot study showing enhancement of compliance with SYN-10, amino-acid precursors and enkephalinase inhibition therapy.

    PubMed

    Chen, Thomas J H; Blum, Kenneth; Payte, James T; Schoolfield, John; Hopper, David; Stanford, Mathew; Braverman, Eric R

    2004-01-01

    We decided to test the hypothesis that possibly by combining a narcotic antagonist and amino-acid therapy consisting of an enkephalinase inhibitor (D-phenylalanine) and neurotransmitter precursors (L-amino- acids) to promote neuronal dopamine release might enhance compliance in methadone patients rapidly detoxified with the narcotic antagonist Trexan (Dupont, Delaware). In this regard, Thanos et al. [J. Neurochem. 78 (2001) 1094] and associates found increases in the dopamine D2 receptors (DRD2) via adenoviral vector delivery of the DRD2 gene into the nucleus accumbens, significantly reduced both ethanol preference (43%) and alcohol intake (64%) of ethanol preferring rats, which recovered as the DRD2, returned to baseline levels. This DRD2 overexpression similarly produced significant reductions in ethanol non-preferring rats, in both alcohol preference (16%) and alcohol intake (75%). This work further suggests that high levels of DRD2 may be protective against alcohol abuse [JAMA 263 (1990) 2055; Arch, Gen. Psychiatr. 48 (1991) 648]. The DRD2 A1 allele has also been shown to associate with heroin addicts in a number of studies. In addition, other dopaminergic receptor gene polymorphisms have also associated with opioid dependence. For example, Kotler et al. [Mol. Phychiatr. 3 (1997) 251] showed that the 7 repeat allele of the DRD4 receptor is significantly overpresented in the opioid-dependent cohort and confers a relative risk of 2.46. This has been confirmed by Li et al. [Mol. Psychiatry 2 (1997) 413] for both the 5 and 7 repeat alleles in Han Chinese case control sample of heroin addicts. Similarly Duaux et al. [Mol. Psychiatry 3 (1998) 333] in French Heroin addicts, found a significant association with homozygotes alleles of the DRD3-Bal 1. A study from NIAAA, provided evidence which strongly suggests that DRD2 is a susceptibility gene for substance abusers across multiple populations (2003). Moreover, there are a number of studies utilizing amino-acid and

  5. The Age of Substitutability

    ERIC Educational Resources Information Center

    Goeller, H. E.; Weinberg, Alvin M.

    1976-01-01

    Dwindling mineral resources might cause a shift from nonrenewable resources to renewable resources and inexhaustible elements such as iron and aluminum. Alternative energy sources such as breeder, fusion, solar, and geothermal power must be developed for production and recycling of materials. Substitution and, hence, living standards ultimately…

  6. Performing Substitute Teaching

    ERIC Educational Resources Information Center

    Bletzer, Keith V.

    2010-01-01

    Formal education is both a right and an obligation bestowed on young people in most all nations of the world. Teachers (adults) and students (youth) form a co-present dyadic contract that must be maintained within the classroom. Substitute teachers fill a role in sustaining the integrity of this teacher-student link, whenever teachers are absent.…

  7. No cheap substitutes.

    PubMed

    Griffiths, Peter

    2016-06-15

    The Nuffield Trust report on reshaping the healthcare workforce was published last month. Its conclusions were widely reported as a recommendation to 'train up' nurses as a solution to junior doctor shortages, with support workers, in turn, substituting for registered nurses. PMID:27305238

  8. Nanoflakes of an aminoacid-based chiral coordination polymer: Synthesis, optical and electrochemical properties, and application in electrochemical sensing of H{sub 2}O{sub 2}

    SciTech Connect

    Zhou, Bo; Liang, Li-Mei; Yao, Jie

    2015-03-15

    Nanoflakes of an aminoacid-based chiral coordination polymer (CP), [Cu{sub 2}(tyr){sub 2}(bipy)]{sub n}, were synthesized successfully in the presence of surfactant, as evidenced by the XRD and SEM results. UV–vis absorption spectrometry and fluorescence spectrometry were used to investigate the optical properties of the CP, which was found to be mainly attributed to the ligands, while the forming of the CP caused only slight change. On the other hand, Cu(II) ions acted as electrocatalytic active sites of the CP, as evidenced by cyclic voltammetry. The CP also showed good performance in the electrochemical sensing of H{sub 2}O{sub 2}: sensitivity of 85.6 mA mol{sup −1} L cm{sup −2}, linear range of 1.0×10{sup −5}–7.69×10{sup −3} M, detection limit of 1.0×10{sup −5} M (S/N=3), and fast response in mere 5 s. - Graphical abstract: Nanoflakes of an aminoacid-based chiral coordination polymer (CP), [Cu{sub 2}(tyr){sub 2}(bipy)]{sub n}, were synthesized successfully and showed good performance in the electrochemical sensing of H{sub 2}O{sub 2}. - Highlights: • Synthesis of nanoflakes of an aminoacid-based chiral CP. • Optical and electrochemical properties resulting respectively from ligands and Cu{sup II}. • Good performance in enzyme-free electrochemical sensing of H{sub 2}O{sub 2}.

  9. Structure of LP2179, the first representative of Pfam family PF08866, suggests a new fold with a role in amino-acid metabolism

    SciTech Connect

    Bakolitsa, Constantina; Kumar, Abhinav; Carlton, Dennis; Miller, Mitchell D.; Krishna, S.Sri; Abdubek, Polat; Astakhova, Tamara; Axelrod, Herbert L.; Chiu, Hsiu-Ju; Clayton, Thomas; Deller, Marc C.; Duan, Lian; Elsliger, Marc-André; Feuerhelm, Julie; Grzechnik, Slawomir K.; Grant, Joanna C.; Han, Gye Won; Jaroszewski, Lukasz; Jin, Kevin K.; Klock, Heath E.; Knuth, Mark W.; Kozbial, Piotr; Marciano, David; McMullan, Daniel; Morse, Andrew T.; Nigoghossian, Edward; Okach, Linda; Oommachen, Silvya; Paulsen, Jessica; Reyes, Ron; Rife, Christopher L.; Tien, Henry J.; Trout, Christina V.; van den Bedem, Henry; Weekes, Dana; Xu, Qingping; Hodgson, Keith O.; Wooley, John; Deacon, Ashley M.; Godzik, Adam; Lesley, Scott A.; Wilson, Ian A.

    2011-08-17

    The structure of LP2179, a member of the PF08866 (DUF1831) family, suggests a novel {alpha} + {beta} fold comprising two {beta}-sheets packed against a single helix. A remote structural similarity to two other uncharacterized protein families specific to the Bacillus genus (PF08868 and PF08968), as well as to prokaryotic S-adenosylmethionine decarboxylases, is consistent with a role in amino-acid metabolism. Genomic neighborhood analysis of LP2179 supports this functional assignment, which might also then be extended to PF08868 and PF08968.

  10. The complete amino-acid sequence of anglerfish somatostatin-28 II. A new octacosapeptide containing the (Tyr7, Gly10) derivative of somatostatin-14 I.

    PubMed

    Morel, A; Chang, J Y; Cohen, P

    1984-09-17

    A new somatostatin-28 has been isolated from the Teleostean fish (Lophius piscatorius) Brockmann organs. Determination of its aminoacid sequence indicates that it corresponds to an octacosapeptide containing in its C-terminal end the Tyr-7 Gly-10 derivative of somatostatin-14 I. This structure is in agreement with the one predicted by Hobart et al. (Nature (1980) 288, 137-141) from a cDNA nucleotide sequence. It demonstrates that, since the corresponding somatostatin-14 II cannot be detected in this organ, S-28 II is a terminal product of prosomatostatin II processing in anglerfish pancreatic islets. PMID:6148264

  11. Protein Adhesion and Ion Substitution (on/in)to Minerals

    NASA Astrophysics Data System (ADS)

    Charlet, L.; Fernandez Martinez, A.; Chapron, Y.; Sahai, N.; Cuello, G.; Brendle, J.; Marichal, C.

    2008-12-01

    Arsenic and pathogenic prion protein-scrapie (PrPsc) are important contaminants which may soil and water for decades, unless they are removed by sorption. Two sorption mechanisms will be discussed, namely the organics (Prp and single aminoacid) adsorption on clay and the arsenic substitution in gypsum. The elucidation of these contrasted mechanisms will be shown to request complementary molecular-mechanical simulations with experimental spectroscopic investigations. As first example, structural studies performed at ILL/ESRF on As-doped gypsum (CaSO4 2H2O) using neutron and X-ray diffraction data and EXAFS were performed to determine how As fits into the bulk of gypsum structure. The combined Rietveld analysis of neutron and X-ray diffraction data shows an expansion of the unit cell volume proportional to the As concentration within the samples. to-sulfate substitution mechanisms were used as simulation starting hypotheses. DFT-based simulations (Mulliken analysis) were used to interpret charge distribution and to show that among the possible mechanisms, a sulphate substitution by either protonated, or fully deprotonated, arsenate ion, only the protonated arsenate substitution could best fit the EXAFS data. In the second example, we used Molecular Dynamics to understand the mechanism of strong binding of the pathogenic PrP peptide with clay mineral surfaces. We modeled only the infectious moiety, PrP92-138, of the whole PrPsc structure, with explicitly solvating water molecules in contact with the cleavage plane of pyrophillite, as a model for montmorillonite without any cationic substitution. Partial residual negative charges on the cleavage plane were balanced with K+ ions. The peptide anchored to the clay surface via up to 10 hydrogen bonds from lysine and histidine residues to oxygen atoms of the siloxane cavities, and a total adsorption energy of 3465 KJ.mol-1 was obtained. Our results were compared to the one obtained by chemical and thermal analysis, 23Na, 1H

  12. Amino-acid selective experiments on uniformly 13C and 15N labeled proteins by MAS NMR: Filtering of lysines and arginines

    NASA Astrophysics Data System (ADS)

    Jehle, Stefan; Rehbein, Kristina; Diehl, Anne; van Rossum, Barth-Jan

    2006-12-01

    Amino-acid selective magic-angle spinning (MAS) NMR experiments can aid the assignment of ambiguous cross-peaks in crowded spectra of solid proteins. In particular for larger proteins, data analysis can be hindered by severe resonance overlap. In such cases, filtering techniques may provide a good alternative to site-specific spin-labeling to obtain unambiguous assignments that can serve as starting points in the assignment procedure. In this paper we present a simple pulse sequence that allows selective excitation of arginine and lysine residues. To achieve this, we make use of a combination of specific cross-polarization for selective excitation [M. Baldus, A.T. Petkova, J. Herzfeld, R.G. Griffin, Cross polarization in the tilted frame: assignment and spectral simplification in heteronuclear spin systems, Mol. Phys. 95 (1998) 1197-1207.] and spin diffusion for transfer along the amino-acid side-chain. The selectivity of the filter is demonstrated with the excitation of lysine and arginine side-chain resonances in a uniformly 13C and 15N labeled protein preparation of the α-spectrin SH3 domain. It is shown that the filter can be applied as a building block in a 13C- 13C lysine-only correlation experiment.

  13. The WD protein Cpc2p is required for repression of Gcn4 protein activity in yeast in the absence of amino-acid starvation.

    PubMed

    Hoffmann, B; Mösch, H U; Sattlegger, E; Barthelmess, I B; Hinnebusch, A; Braus, G H

    1999-02-01

    The CPC2 gene of the budding yeast Saccharomyces cerevisiae encodes a G beta-like WD protein which is involved in regulating the activity of the general control activator Gcn4p. The CPC2 gene encodes a premRNA which is spliced and constitutively expressed in the presence or absence of amino acids. Loss of CPC2 gene function suppresses a deletion of the GCN2 gene encoding the general control sensor kinase, but not a deletion in the GCN4 gene. The resulting phenotype has resistance against amino-acid analogues. The Neurospora crassa cpc-2 and the rat RACK1 genes are homologues of CPC2 that complement the yeast cpc2 deletion. The cpc2 delta mutation leads to increased transcription of Gcn4p-dependent genes under non-starvation conditions without increasing GCN4 expression or the DNA binding activity of Gcn4p. Cpc2p-mediated transcriptional repression requires the Gcn4p transcriptional activator and a Gcn4p recognition element in the target promoter. Frameshift mutations resulting in a shortened G beta-like protein cause a different phenotype that has sensitivity against amino-acid analogues similar to a gcn2 deletion. Cpc2p seems to be part of an additional control of Gcn4p activity, independent of its translational regulation. PMID:10048025

  14. The 1.9 A Structure of the Branched-Chain Amino-Acid Transaminase (IlvE) from Mycobacterium tuberculosis

    SciTech Connect

    Tremblay, L.; Blanchard, J

    2009-01-01

    Unlike mammals, bacteria encode enzymes that synthesize branched-chain amino acids. The pyridoxal 5'-phosphate-dependent transaminase performs the final biosynthetic step in these pathways, converting keto acid precursors into {alpha}-amino acids. The branched-chain amino-acid transaminase from Mycobacterium tuberculosis (MtIlvE) has been crystallized and its structure has been solved at 1.9 {angstrom} resolution. The MtIlvE monomer is composed of two domains that interact to form the active site. The biologically active form of IlvE is a homodimer in which each monomer contributes a substrate-specificity loop to the partner molecule. Additional substrate selectivity may be imparted by a conserved N-terminal Phe30 residue, which has previously been observed to shield the active site in the type IV fold homodimer. The active site of MtIlvE contains density corresponding to bound PMP, which is likely to be a consequence of the presence of tryptone in the crystallization medium. Additionally, two cysteine residues are positioned at the dimer interface for disulfide-bond formation under oxidative conditions. It is unknown whether they are involved in any regulatory activities analogous to those of the human mitochondrial branched-chain amino-acid transaminase.

  15. Apoptotic Killing of Breast Cancer Cells by IgYs Produced Against a Small 21 Aminoacid Epitope of the Human TRAIL-2 Receptor.

    PubMed

    Amirijavid1, Shaghayegh; Entezari, Maliheh; Movafagh, Abolfazl; Hashemi, Mehrdad; Mosavi-Jarahi, Alireza; Dehghani, Hossein

    2016-01-01

    TRAIL, tumor necrosis factor (TNF)-related apoptosis-inducing ligand belongs to one of important cytokine superfamilIES, tumor necrosis factor (TNFα) . TRAIL-2 receptor agonists activate several cell signaling pathways in cells in different manners and could lead to apoptosis or necrosis. Agonistic egg yolk antibodies like IgY which have been developed in a selective manner could activate TRAIL death receptors such as TRAIL-2 (DR5) and thus apoptosis signaling. We here investigated induction of apoptosis in human breast cancer cells (MCF7 cell line) by an IgY produced against an 21 aminoacid epitope of the human TRAIL-2 receptor. As the first step a small peptide of 21 aminoacids choosen from the extracellular domain of DR5 protein was produced with a peptide synthesizer. After control assays and confirmation of the correct amino acid sequence, it was injected to hens immunized to achieve high affinity IgYs. At the next step, the produced IgYs were extracted and examined for specificity against DR5 protein by ELISA assay. Subsequently, the anticancer effect of such IgYs was determined by MTT assay in the MCF7 human breast cancer cell line. The produced peptides successfully immunized hens and the produced antibodies which accumulated in egg yolk specifically recognized the DR5 protein. IgYs exerted significant toxicity and killed MCF7 cells as shown by MTT assay. PMID:27165241

  16. Clinical applications of skin substitutes.

    PubMed

    Nyame, Theodore T; Chiang, H Abraham; Orgill, Dennis P

    2014-08-01

    A unique understanding of the components of mammalian skin has led to the development of numerous skin substitutes. These skin substitutes attempt to compensate for functional and physiologic deficits present in damaged tissue. Skin substitutes, when appropriately applied in optimized settings, offer a promising solution to difficult wound management. The body of literature on skin substitutes increases as the understanding of tissue engineering and molecular biology expands. Given the high cost of these products, future randomized large prospective studies are needed to guide the clinical applications of skin substitutes. PMID:25085091

  17. Methodologies in creating skin substitutes.

    PubMed

    Nicholas, Mathew N; Jeschke, Marc G; Amini-Nik, Saeid

    2016-09-01

    The creation of skin substitutes has significantly decreased morbidity and mortality of skin wounds. Although there are still a number of disadvantages of currently available skin substitutes, there has been a significant decline in research advances over the past several years in improving these skin substitutes. Clinically most skin substitutes used are acellular and do not use growth factors to assist wound healing, key areas of potential in this field of research. This article discusses the five necessary attributes of an ideal skin substitute. It comprehensively discusses the three major basic components of currently available skin substitutes: scaffold materials, growth factors, and cells, comparing and contrasting what has been used so far. It then examines a variety of techniques in how to incorporate these basic components together to act as a guide for further research in the field to create cellular skin substitutes with better clinical results. PMID:27154041

  18. 40 CFR 721.10034 - Substituted pyridine coupled with diazotized substituted nitrobenzonitrile, diazotized...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Substituted pyridine coupled with... Specific Chemical Substances § 721.10034 Substituted pyridine coupled with diazotized substituted... as substituted pyridine coupled with diazotized substituted nitrobenzonitrile, diazotized...

  19. 40 CFR 721.10034 - Substituted pyridine coupled with diazotized substituted nitrobenzonitrile, diazotized...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Substituted pyridine coupled with... Specific Chemical Substances § 721.10034 Substituted pyridine coupled with diazotized substituted... as substituted pyridine coupled with diazotized substituted nitrobenzonitrile, diazotized...

  20. Polyimides comprising substituted benzidines

    NASA Technical Reports Server (NTRS)

    Harris, Frank W. (Inventor)

    1991-01-01

    A new class of polyimides and copolyimides made from substituted benzidines and aromatic dianhydrides and other aromatic diamines. The polyimides obtained with said diamines are distinguished by excellent thermal, excellent solubility, excellent electrical properties such as very low dielectric constants, excellent clarity and mechanical properties making the polyimides ideally suited as coating materials for microelectronic apparatii, as membranes for selective molecular or gas separation, as fibers in molecular composites, as high tensile strength, high compression strength fibers, as film castable coatings, or as fabric components.

  1. Trifluoromethyl-substituted polymers

    NASA Technical Reports Server (NTRS)

    1993-01-01

    Current work sponsored by the grant at Southwest Texas State University is directed toward the synthesis and characterization of: (1) N-alkylated polyamides derived from o-fluorinated diacids; (2) highly fluorinated polyethers; (3) polyesters derived from 2-hydroxy-2-propyl substituted arenes and/or 2,5-difluoroterephthalic acid; and (4) silicon-containing fluoropolymers. Work during the period from 1 July to 31 Dec. 1993 focused primarily on items 3 and 4 and on the development of a phosphorus containing modification of '12F-PEK.'

  2. PAT4 levels control amino-acid sensitivity of rapamycin-resistant mTORC1 from the Golgi and affect clinical outcome in colorectal cancer

    PubMed Central

    Fan, S-J; Snell, C; Turley, H; Li, J-L; McCormick, R; Perera, S M W; Heublein, S; Kazi, S; Azad, A; Wilson, C; Harris, A L; Goberdhan, D C I

    2016-01-01

    Tumour cells can use strategies that make them resistant to nutrient deprivation to outcompete their neighbours. A key integrator of the cell's responses to starvation and other stresses is amino-acid-dependent mechanistic target of rapamycin complex 1 (mTORC1). Activation of mTORC1 on late endosomes and lysosomes is facilitated by amino-acid transporters within the solute-linked carrier 36 (SLC36) and SLC38 families. Here, we analyse the functions of SLC36 family member, SLC36A4, otherwise known as proton-assisted amino-acid transporter 4 (PAT4), in colorectal cancer. We show that independent of other major pathological factors, high PAT4 expression is associated with reduced relapse-free survival after colorectal cancer surgery. Consistent with this, PAT4 promotes HCT116 human colorectal cancer cell proliferation in culture and tumour growth in xenograft models. Inducible knockdown in HCT116 cells reveals that PAT4 regulates a form of mTORC1 with two distinct properties: first, it preferentially targets eukaryotic translation initiation factor 4E-binding protein 1 (4E-BP1), and second, it is resistant to rapamycin treatment. Furthermore, in HCT116 cells two non-essential amino acids, glutamine and serine, which are often rapidly metabolised by tumour cells, regulate rapamycin-resistant mTORC1 in a PAT4-dependent manner. Overexpressed PAT4 is also able to promote rapamycin resistance in human embryonic kidney-293 cells. PAT4 is predominantly associated with the Golgi apparatus in a range of cell types, and in situ proximity ligation analysis shows that PAT4 interacts with both mTORC1 and its regulator Rab1A on the Golgi. These findings, together with other studies, suggest that differentially localised intracellular amino-acid transporters contribute to the activation of alternate forms of mTORC1. Furthermore, our data predict that colorectal cancer cells with high PAT4 expression will be more resistant to depletion of serine and glutamine, allowing them to

  3. PAT4 levels control amino-acid sensitivity of rapamycin-resistant mTORC1 from the Golgi and affect clinical outcome in colorectal cancer.

    PubMed

    Fan, S-J; Snell, C; Turley, H; Li, J-L; McCormick, R; Perera, S M W; Heublein, S; Kazi, S; Azad, A; Wilson, C; Harris, A L; Goberdhan, D C I

    2016-06-01

    Tumour cells can use strategies that make them resistant to nutrient deprivation to outcompete their neighbours. A key integrator of the cell's responses to starvation and other stresses is amino-acid-dependent mechanistic target of rapamycin complex 1 (mTORC1). Activation of mTORC1 on late endosomes and lysosomes is facilitated by amino-acid transporters within the solute-linked carrier 36 (SLC36) and SLC38 families. Here, we analyse the functions of SLC36 family member, SLC36A4, otherwise known as proton-assisted amino-acid transporter 4 (PAT4), in colorectal cancer. We show that independent of other major pathological factors, high PAT4 expression is associated with reduced relapse-free survival after colorectal cancer surgery. Consistent with this, PAT4 promotes HCT116 human colorectal cancer cell proliferation in culture and tumour growth in xenograft models. Inducible knockdown in HCT116 cells reveals that PAT4 regulates a form of mTORC1 with two distinct properties: first, it preferentially targets eukaryotic translation initiation factor 4E-binding protein 1 (4E-BP1), and second, it is resistant to rapamycin treatment. Furthermore, in HCT116 cells two non-essential amino acids, glutamine and serine, which are often rapidly metabolised by tumour cells, regulate rapamycin-resistant mTORC1 in a PAT4-dependent manner. Overexpressed PAT4 is also able to promote rapamycin resistance in human embryonic kidney-293 cells. PAT4 is predominantly associated with the Golgi apparatus in a range of cell types, and in situ proximity ligation analysis shows that PAT4 interacts with both mTORC1 and its regulator Rab1A on the Golgi. These findings, together with other studies, suggest that differentially localised intracellular amino-acid transporters contribute to the activation of alternate forms of mTORC1. Furthermore, our data predict that colorectal cancer cells with high PAT4 expression will be more resistant to depletion of serine and glutamine, allowing them to

  4. Borate substituted ettringites

    SciTech Connect

    Csetenyi, L.J.; Glasser, F.P.

    1993-12-31

    The setting of cement is adversely affected by soluble borates. To reduce interference, the extent to which borate can be insolubilized has been investigated. One specific mechanism of insolubilization is by inclusion into ettringite. Ettringite, Ca{sub 6}Al{sub 2}(SO{sub 4}){sub 3}(OH){sub 12}{center_dot}26H{sub 2}O, is a normal and stable constituent of Portland cement. It has an open but non-zeolitic framework. Borate can substitute partially or fully for sulfate. Formation conditions, solubility and stability of borate ettringites, Ca{sub 6}Al{sub 2}(BO{sub 4}){sub 2-4}(OH,O){sub 12}{center_dot}26H{sub 2}O, are characterized using XRD, IR, DTA, and SEM. The potential durability of borate ettringites in a repository environment have been assessed by exposing it to Na-sulfate and Na-carbonate attack at different concentrations. Ion exchange occurs; back substitution of borate by sulfate is incomplete; high carbonate concentrations can, however, decompose borate ettringite. On heat treatment up to 85{degrees}C the crystalline morphology and the OH arrangement of the structure are altered, but the X-ray powder pattern, and hence its structural framework are largely unaffected. It is concluded that ettringite has potential to reduce the solubility of borate.

  5. Nanoflakes of an aminoacid-based chiral coordination polymer: Synthesis, optical and electrochemical properties, and application in electrochemical sensing of H2O2

    NASA Astrophysics Data System (ADS)

    Zhou, Bo; Liang, Li-Mei; Yao, Jie

    2015-03-01

    Nanoflakes of an aminoacid-based chiral coordination polymer (CP), [Cu2(tyr)2(bipy)]n, were synthesized successfully in the presence of surfactant, as evidenced by the XRD and SEM results. UV-vis absorption spectrometry and fluorescence spectrometry were used to investigate the optical properties of the CP, which was found to be mainly attributed to the ligands, while the forming of the CP caused only slight change. On the other hand, Cu(II) ions acted as electrocatalytic active sites of the CP, as evidenced by cyclic voltammetry. The CP also showed good performance in the electrochemical sensing of H2O2: sensitivity of 85.6 mA mol-1 L cm-2, linear range of 1.0×10-5-7.69×10-3 M, detection limit of 1.0×10-5 M (S/N=3), and fast response in mere 5 s.

  6. Explicit Substitutions and All That

    NASA Technical Reports Server (NTRS)

    Ayala-Rincon, Mauricio; Munoz, Cesar; Busnell, Dennis M. (Technical Monitor)

    2000-01-01

    Explicit substitution calculi are extensions of the Lambda-calculus where the substitution mechanism is internalized into the theory. This feature makes them suitable for implementation and theoretical study of logic-based tools such as strongly typed programming languages and proof assistant systems. In this paper we explore new developments on two of the most successful styles of explicit substitution calculi: the lambda(sigma)- and lambda(s(e))-calculi.

  7. Explicit Substitutions and All That

    NASA Technical Reports Server (NTRS)

    Ayala-Rincon, Mauricio; Munoz, Cesar

    2000-01-01

    Explicit substitution calculi are extensions of the lambda-calculus where the substitution mechanism is internalized into the theory. This feature makes them suitable for implementation and theoretical study of logic-based tools such as strongly typed programming languages and proof assistant systems. In this paper we explore new developments on two of the most successful styles of explicit substitution calculi: the lambda sigma- and lambda S(e)-calculi.

  8. Trifluoromethyl-substituted tetrathiafulvalenes

    PubMed Central

    Jeannin, Olivier; Barrière, Frédéric

    2015-01-01

    Summary A series of tetrathiafulvalenes functionalized with one or two trifluoromethyl electron-withdrawing groups (EWG) is obtained by phosphite coupling involving CF3-substituted 1,3-dithiole-2-one derivatives. The relative effects of the EWG such as CF3, CO2Me and CN on the TTF core were investigated from a combination of structural, electrochemical, spectrochemical and theoretical investigations. Electrochemical data confirm the good correlations between the first oxidation potential of the TTF derivatives and the σmeta Hammet parameter, thus in the order CO2Me < CF3 < CN, indicating that, in any case, the mesomeric effect of the substituents is limited. Besides, crystal structure determinations show that the deformation of the unsymmetrically substituted dithiole rings, when bearing one, or two different EWG, and attributed to the mesomeric effect of ester or nitrile groups, is not notably modified or counter-balanced by the introduction of a neighboring trifluoromethyl group. DFT calculations confirm these observations and also show that the low energy HOMO–LUMO absorption band found in nitrile or ester-substituted TTFs is not found in TTF-CF3, where, as in TTF itself, the low energy absorption band is essentially attributable to a HOMO→LUMO + 1 transition. Despite relatively high oxidation potentials, these donor molecules with CF3 EWG can be involved in charge transfer complexes or cation radical salts, as reported here for the CF3-subsituted EDT-TTF donor molecule. A neutral charge transfer complex with TCNQ, (EDT-TTF-CF3)2(TCNQ) was isolated and characterized through alternated stacks of EDT-TTF-CF3 dimers and TCNQ in the solid state. A radical cation salt of EDT-TTF-CF3 is also obtained upon electrocrystallisation in the presence of the FeCl4 − anion. In this salt, formulated as (EDT-TTF-CF3)(FeCl4), the (EDT-TTF-CF3)+• radical cations are associated two-by-two into centrosymmetric dyads with a strong pairing of the radical species in a singlet

  9. Trifluoromethyl-substituted tetrathiafulvalenes.

    PubMed

    Jeannin, Olivier; Barrière, Frédéric; Fourmigué, Marc

    2015-01-01

    A series of tetrathiafulvalenes functionalized with one or two trifluoromethyl electron-withdrawing groups (EWG) is obtained by phosphite coupling involving CF3-substituted 1,3-dithiole-2-one derivatives. The relative effects of the EWG such as CF3, CO2Me and CN on the TTF core were investigated from a combination of structural, electrochemical, spectrochemical and theoretical investigations. Electrochemical data confirm the good correlations between the first oxidation potential of the TTF derivatives and the σmeta Hammet parameter, thus in the order CO2Me < CF3 < CN, indicating that, in any case, the mesomeric effect of the substituents is limited. Besides, crystal structure determinations show that the deformation of the unsymmetrically substituted dithiole rings, when bearing one, or two different EWG, and attributed to the mesomeric effect of ester or nitrile groups, is not notably modified or counter-balanced by the introduction of a neighboring trifluoromethyl group. DFT calculations confirm these observations and also show that the low energy HOMO-LUMO absorption band found in nitrile or ester-substituted TTFs is not found in TTF-CF3, where, as in TTF itself, the low energy absorption band is essentially attributable to a HOMO→LUMO + 1 transition. Despite relatively high oxidation potentials, these donor molecules with CF3 EWG can be involved in charge transfer complexes or cation radical salts, as reported here for the CF3-subsituted EDT-TTF donor molecule. A neutral charge transfer complex with TCNQ, (EDT-TTF-CF3)2(TCNQ) was isolated and characterized through alternated stacks of EDT-TTF-CF3 dimers and TCNQ in the solid state. A radical cation salt of EDT-TTF-CF3 is also obtained upon electrocrystallisation in the presence of the FeCl4 (-) anion. In this salt, formulated as (EDT-TTF-CF3)(FeCl4), the (EDT-TTF-CF3)(+•) radical cations are associated two-by-two into centrosymmetric dyads with a strong pairing of the radical species in a singlet state

  10. Displacement, Substitution, Sublimation: A Bibliography.

    ERIC Educational Resources Information Center

    Pedrini, D. T.; Pedrini, Bonnie C.

    Sigmund Freund worked with the mechanisms of displacement, substitution, and sublimation. These mechanisms have many similarities and have been studied diagnostically and therapeutically. Displacement and substitution seem to fit in well with phobias, hysterias, somatiyations, prejudices, and scapegoating. Phobias, prejudices, and scapegoating…

  11. The Replacement of 10 Non-Conserved Residues in the Core Protein of JFH-1 Hepatitis C Virus Improves Its Assembly and Secretion

    PubMed Central

    Etienne, Loïc; Blanchard, Emmanuelle; Boyer, Audrey; Desvignes, Virginie; Gaillard, Julien; Meunier, Jean-Christophe; Roingeard, Philippe; Hourioux, Christophe

    2015-01-01

    Hepatitis C virus (HCV) assembly is still poorly understood. It is thought that trafficking of the HCV core protein to the lipid droplet (LD) surface is essential for its multimerization and association with newly synthesized HCV RNA to form the viral nucleocapsid. We carried out a mapping analysis of several complete HCV genomes of all genotypes, and found that the genotype 2 JFH-1 core protein contained 10 residues different from those of other genotypes. The replacement of these 10 residues of the JFH-1 strain sequence with the most conserved residues deduced from sequence alignments greatly increased virus production. Confocal microscopy of the modified JFH-1 strain in cell culture showed that the mutated JFH-1 core protein, C10M, was present mostly at the endoplasmic reticulum (ER) membrane, but not at the surface of the LDs, even though its trafficking to these organelles was possible. The non-structural 5A protein of HCV was also redirected to ER membranes and colocalized with the C10M core protein. Using a Semliki forest virus vector to overproduce core protein, we demonstrated that the C10M core protein was able to form HCV-like particles, unlike the native JFH-1 core protein. Thus, the substitution of a few selected residues in the JFH-1 core protein modified the subcellular distribution and assembly properties of the protein. These findings suggest that the early steps of HCV assembly occur at the ER membrane rather than at the LD surface. The C10M-JFH-1 strain will be a valuable tool for further studies of HCV morphogenesis. PMID:26339783

  12. A novel skew analysis reveals substitution asymmetries linked to genetic code GC-biases and PolIII a-subunit isoforms

    PubMed Central

    Apostolou-Karampelis, Konstantinos; Nikolaou, Christoforos; Almirantis, Yannis

    2016-01-01

    Strand biases reflect deviations from a null expectation of DNA evolution that assumes strand-symmetric substitution rates. Here, we present strong evidence that nearest-neighbour preferences are a strand-biased feature of bacterial genomes, indicating neighbour-dependent substitution asymmetries. To detect such asymmetries we introduce an alignment free index (relative abundance skews). The profiles of relative abundance skews along coding sequences can trace the phylogenetic relations of bacteria, suggesting that the patterns of neighbour-dependent substitution strand-biases are not common among different lineages, but are rather species-specific. Analysis of neighbour-dependent and codon-site skews sheds light on the origins of substitution asymmetries. Via a simple model we argue that the structure of the genetic code imposes position-dependent substitution strand-biases along coding sequences, as a response to GC mutation pressure. Thus, the organization of the genetic code per se can lead to an uneven distribution of nucleotides among different codon sites, even when requirements for specific codons and amino-acids are not accounted for. Moreover, our results suggest that strand-biases in replication fidelity of PolIII α-subunit induce substitution asymmetries, both neighbour-dependent and independent, on a genome scale. The role of DNA repair systems, such as transcription-coupled repair, is also considered. PMID:27345720

  13. How Do Substitute Teachers Substitute? An Empirical Study of Substitute-Teacher Labor Supply

    ERIC Educational Resources Information Center

    Gershenson, Seth

    2012-01-01

    This paper examines the daily labor supply of a potentially important, but often overlooked, source of instruction in U.S. public schools: substitute teachers. I estimate a sequential binary-choice model of substitute teachers' job-offer acceptance decisions using data on job offers made by a randomized automated calling system. Importantly, this…

  14. 40 CFR 721.10126 - Alkyl amino substituted triazine amino substituted benezenesulfonic acid reaction product with...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... substituted benezenesulfonic acid reaction product with naphthalenesulfonato azo substituted phenyl azo... CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.10126 Alkyl amino substituted triazine amino substituted benezenesulfonic acid reaction product with naphthalenesulfonato...

  15. 40 CFR 721.10126 - Alkyl amino substituted triazine amino substituted benezenesulfonic acid reaction product with...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... substituted benezenesulfonic acid reaction product with naphthalenesulfonato azo substituted phenyl azo... CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.10126 Alkyl amino substituted triazine amino substituted benezenesulfonic acid reaction product with naphthalenesulfonato...

  16. 40 CFR 721.3063 - Substituted phenyl azo substituted phenyl esters (generic name).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Substituted phenyl azo substituted... Significant New Uses for Specific Chemical Substances § 721.3063 Substituted phenyl azo substituted phenyl... chemical substances identified generically as substituted phenyl azo substituted phenyl esters (PMNs...

  17. 40 CFR 721.3063 - Substituted phenyl azo substituted phenyl esters (generic name).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Substituted phenyl azo substituted... Significant New Uses for Specific Chemical Substances § 721.3063 Substituted phenyl azo substituted phenyl... as substituted phenyl azo substituted phenyl esters (PMNs P-95-655, P-95-782 and P-95-871)...

  18. 40 CFR 721.3063 - Substituted phenyl azo substituted phenyl esters (generic name).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Substituted phenyl azo substituted... Significant New Uses for Specific Chemical Substances § 721.3063 Substituted phenyl azo substituted phenyl... chemical substances identified generically as substituted phenyl azo substituted phenyl esters (PMNs...

  19. DESIGNING ENVIRONMENTALLY BENIGN SOLVENT SUBSTITUTES

    EPA Science Inventory

    Since the signing of 1987 Montreal Protocol, reducing and eliminating the use of harmful solvents has become an internationally imminent environmental protection mission. Solvent substitution is an effective way to achieve this goal. The Program for Assisting the Replacement of...

  20. Nucleophilic Substitution by Benzodithioate Anions.

    ERIC Educational Resources Information Center

    Bonnans-Plaisance, Chantal; Gressier, Jean-Claude

    1988-01-01

    Describes a two-session experiment designed to provide a good illustration of, and to improve student knowledge of, the Grignard reaction and nucleophilic substitution. Discusses the procedure, experimental considerations, and conclusion of this experiment. (CW)

  1. The amino-acid sequence of the glucose/mannose-specific lectin isolated from Parkia platycephala seeds reveals three tandemly arranged jacalin-related domains.

    PubMed

    Mann, K; Farias, C M; Del Sol, F G; Santos, C F; Grangeiro, T B; Nagano, C S; Cavada, B S; Calvete, J J

    2001-08-01

    A mannose/glucose-specific lectin was isolated from seeds of Parkia platycephala, the most primitive subfamily of Leguminosae plants. The molecular mass of the purified lectin determined by mass spectrometry was 47 946 +/- 6 Da (by electrospray ionization) and 47 951 +/- 9 Da (by matrix-assisted laser-desoption ionization). The apparent molecular mass of the lectin in solutions of pH in the range 4.5-8.5 determined by analytical ultracentrifugation equilibrium sedimentation was 94 +/- 3 kDa, showing that the protein behaved as a non-pH-dependent dimer. The amino-acid sequence of the Parkia lectin was determined by Edman degradation of overlapping peptides. This is the first report of the primary structure of a Mimosoideae lectin. The protein contained a blocked N-terminus and a single, nonglycosylated polypeptide chain composed of three tandemly arranged homologous domains. Each of these domains shares sequence similarity with jacalin-related lectin monomers from Asteraceae, Convolvulaceae, Moraceae, Musaceae, Gramineae, and Fagaceae plant families. Based on this homology, we predict that each Parkia lectin repeat may display a beta prism fold similar to that observed in the crystal structure of the lectin from Helianthus tuberosus. The P. platycephala lectin also shows sequence similarity with stress- and pathogen-upregulated defence genes of a number of different plants, suggesting a common ancestry for jacalin-related lectins and inducible defence proteins. PMID:11502201

  2. Exploring the structure of the 100 amino-acid residue long N-terminus of the plant antenna protein CP29.

    PubMed

    Shabestari, Maryam Hashemi; Wolfs, Cor J A M; Spruijt, Ruud B; van Amerongen, Herbert; Huber, Martina

    2014-03-18

    The structure of the unusually long (∼100 amino-acid residues) N-terminal domain of the light-harvesting protein CP29 of plants is not defined in the crystal structure of this membrane protein. We studied the N-terminus using two electron paramagnetic resonance (EPR) approaches: the rotational diffusion of spin labels at 55 residues with continuous-wave EPR, and three sets of distances with a pulsed EPR method. The N-terminus is relatively structured. Five regions that differ considerably in their dynamics are identified. Two regions have low rotational diffusion, one of which shows α-helical character suggesting contact with the protein surface. This immobile part is flanked by two highly dynamic, unstructured regions (loops) that cover residues 10-22 and 82-91. These loops may be important for the interaction with other light-harvesting proteins. The region around residue 4 also has low rotational diffusion, presumably because it attaches noncovalently to the protein. This section is close to a phosphorylation site (Thr-6) in related proteins, such as those encoded by the Lhcb4.2 gene. Phosphorylation might influence the interaction with other antenna complexes, thereby regulating the supramolecular organization in the thylakoid membrane. PMID:24655510

  3. Exploring the Structure of the 100 Amino-Acid Residue Long N-Terminus of the Plant Antenna Protein CP29

    PubMed Central

    Shabestari, Maryam Hashemi; Wolfs, Cor J.A.M.; Spruijt, Ruud B.; van Amerongen, Herbert; Huber, Martina

    2014-01-01

    The structure of the unusually long (∼100 amino-acid residues) N-terminal domain of the light-harvesting protein CP29 of plants is not defined in the crystal structure of this membrane protein. We studied the N-terminus using two electron paramagnetic resonance (EPR) approaches: the rotational diffusion of spin labels at 55 residues with continuous-wave EPR, and three sets of distances with a pulsed EPR method. The N-terminus is relatively structured. Five regions that differ considerably in their dynamics are identified. Two regions have low rotational diffusion, one of which shows α-helical character suggesting contact with the protein surface. This immobile part is flanked by two highly dynamic, unstructured regions (loops) that cover residues 10–22 and 82–91. These loops may be important for the interaction with other light-harvesting proteins. The region around residue 4 also has low rotational diffusion, presumably because it attaches noncovalently to the protein. This section is close to a phosphorylation site (Thr-6) in related proteins, such as those encoded by the Lhcb4.2 gene. Phosphorylation might influence the interaction with other antenna complexes, thereby regulating the supramolecular organization in the thylakoid membrane. PMID:24655510

  4. Identification of new aminoacid amides containing the imidazo[2,1-b]benzothiazol-2-ylphenyl moiety as inhibitors of tumorigenesis by oncogenic Met signaling.

    PubMed

    Furlan, Alessandro; Colombo, Francesco; Kover, Andrea; Issaly, Nathalie; Tintori, Cristina; Angeli, Lucilla; Leroux, Vincent; Letard, Sébastien; Amat, Mercedes; Asses, Yasmine; Maigret, Bernard; Dubreuil, Patrice; Botta, Maurizio; Dono, Rosanna; Bosch, Joan; Piccolo, Oreste; Passarella, Daniele; Maina, Flavio

    2012-01-01

    The Met receptor tyrosine kinase is a promising target in anticancer therapies for its role during tumor evolution and resistance to treatment. It is characterized by an unusual structural plasticity as its active site accepts different inhibitor binding modes. Such feature can be exploited to identify distinct agents targeting tumor dependence and/or resistance by oncogenic Met. Here we report the identification of bioactive agents, featuring a new 4-(imidazo[2,1-b]benzothiazol-2-yl)phenyl moiety, targeting cancer cells dependent on oncogenic Met. One of these compounds (7c; Triflorcas) impairs survival, anchorage-independent growth, and in vivo tumorigenesis, without showing side effects. Our medicinal chemistry strategy was based on an in-house Met-focused library of aminoacid-amide derivatives enriched through structure-based computer modeling, taking into account the Met multiple-binding-mode feature. Altogether, our findings show how a rational structure-based drug design approach coupled to cell-based drug evaluation strategies can be applied in medicinal chemistry to identify new agents targeting a given oncogenic-dependency setting. PMID:22138308

  5. ERK7 is a negative regulator of protein secretion in response to amino-acid starvation by modulating Sec16 membrane association

    PubMed Central

    Zacharogianni, Margarita; Kondylis, Vangelis; Tang, Yang; Farhan, Hesso; Xanthakis, Despina; Fuchs, Florian; Boutros, Michael; Rabouille, Catherine

    2011-01-01

    RNAi screening for kinases regulating the functional organization of the early secretory pathway in Drosophila S2 cells has identified the atypical Mitotic-Associated Protein Kinase (MAPK) Extracellularly regulated kinase 7 (ERK7) as a new modulator. We found that ERK7 negatively regulates secretion in response to serum and amino-acid starvation, in both Drosophila and human cells. Under these conditions, ERK7 turnover through the proteasome is inhibited, and the resulting higher levels of this kinase lead to a modification in a site within the C-terminus of Sec16, a key ER exit site component. This post-translational modification elicits the cytoplasmic dispersion of Sec16 and the consequent disassembly of the ER exit sites, which in turn results in protein secretion inhibition. We found that ER exit site disassembly upon starvation is TOR complex 1 (TORC1) independent, showing that under nutrient stress conditions, cell growth is not only inhibited at the transcriptional and translational levels, but also independently at the level of secretion by inhibiting the membrane flow through the early secretory pathway. These results reveal the existence of new signalling circuits participating in the complex regulation of cell growth. PMID:21847093

  6. A High Load of Non-neutral Amino-Acid Polymorphisms Explains High Protein Diversity Despite Moderate Effective Population Size in a Marine Bivalve With Sweepstakes Reproduction

    PubMed Central

    Harrang, Estelle; Lapègue, Sylvie; Morga, Benjamin; Bierne, Nicolas

    2013-01-01

    Marine bivalves show among the greatest allozyme diversity ever reported in Eukaryotes, putting them historically at the heart of the neutralist−selectionist controversy on the maintenance of genetic variation. Although it is now acknowledged that this high diversity is most probably a simple consequence of a large population size, convincing support for this explanation would require a rigorous assessment of the silent nucleotide diversity in natural populations of marine bivalves, which has not yet been done. This study investigated DNA sequence polymorphism in a set of 37 nuclear loci in wild samples of the flat oyster Ostrea edulis. Silent diversity was found to be only moderate (0.7%), and there was no departure from demographic equilibrium under the Wright-Fisher model, suggesting that the effective population size might not be as large as might have been expected. In accordance with allozyme heterozygosity, nonsynonymous diversity was comparatively very high (0.3%), so that the nonsynonymous to silent diversity ratio reached a value rarely observed in any other organism. We estimated that one-quarter of amino acid-changing mutations behave as neutral in O. edulis, and as many as one-third are sufficiently weakly selected to segregate at low frequency in the polymorphism. Finally, we inferred that one oyster is expected to carry more than 4800 non-neutral alleles (or 4.2 cM−1). We conclude that a high load of segregating non-neutral amino-acid polymorphisms contributes to high protein diversity in O. edulis. The high fecundity of marine bivalves together with an unpredictable and highly variable success of reproduction and recruitment (sweepstakes reproduction) might produce a greater decoupling between Ne and N than in other organisms with lower fecundities, and we suggest this could explain why a higher segregating load could be maintained for a given silent mutation effective size. PMID:23390609

  7. 40 CFR 721.2577 - Copper complex of (substituted sulfonaphthyl azo substituted phenyl) disulfonaphthyl azo, amine...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Copper complex of (substituted... Copper complex of (substituted sulfonaphthyl azo substituted phenyl) disulfonaphthyl azo, amine salt... substances identified generically as copper complex of (substituted sulfonaphthyl azo substituted...

  8. 40 CFR 721.2577 - Copper complex of (substituted sulfonaphthyl azo substituted phenyl) disulfonaphthyl azo, amine...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Copper complex of (substituted... Copper complex of (substituted sulfonaphthyl azo substituted phenyl) disulfonaphthyl azo, amine salt... substances identified generically as copper complex of (substituted sulfonaphthyl azo substituted...

  9. 40 CFR 721.2577 - Copper complex of (substituted sulfonaphthyl azo substituted phenyl) disulfonaphthyl azo, amine...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Copper complex of (substituted... Copper complex of (substituted sulfonaphthyl azo substituted phenyl) disulfonaphthyl azo, amine salt... substances identified generically as copper complex of (substituted sulfonaphthyl azo substituted...

  10. 40 CFR 721.2577 - Copper complex of (substituted sulfonaphthyl azo substituted phenyl) disulfonaphthyl azo, amine...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Copper complex of (substituted... Copper complex of (substituted sulfonaphthyl azo substituted phenyl) disulfonaphthyl azo, amine salt... substances identified generically as copper complex of (substituted sulfonaphthyl azo substituted...

  11. 40 CFR 721.10126 - Alkyl amino substituted triazine amino substituted benezenesulfonic acid reaction product with...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... substituted benzenesulfonic acid copper compound (generic). 721.10126 Section 721.10126 Protection of... substituted phenyl azo substituted benzenesulfonic acid copper compound (generic). (a) Chemical substance and... substituted phenyl azo substituted benzenesulfonic acid copper compound (PMN P-06-689) is subject to...

  12. 40 CFR 721.10126 - Alkyl amino substituted triazine amino substituted benezenesulfonic acid reaction product with...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... substituted benzenesulfonic acid copper compound (generic). 721.10126 Section 721.10126 Protection of... substituted phenyl azo substituted benzenesulfonic acid copper compound (generic). (a) Chemical substance and... substituted phenyl azo substituted benzenesulfonic acid copper compound (PMN P-06-689) is subject to...

  13. 40 CFR 721.10126 - Alkyl amino substituted triazine amino substituted benezenesulfonic acid reaction product with...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... substituted benzenesulfonic acid copper compound (generic). 721.10126 Section 721.10126 Protection of... substituted phenyl azo substituted benzenesulfonic acid copper compound (generic). (a) Chemical substance and... substituted phenyl azo substituted benzenesulfonic acid copper compound (PMN P-06-689) is subject to...

  14. Magnesium substitution in brushite cements.

    PubMed

    Alkhraisat, Mohammad Hamdan; Cabrejos-Azama, Jatsue; Rodríguez, Carmen Rueda; Jerez, Luis Blanco; Cabarcos, Enrique López

    2013-01-01

    The use of magnesium-doped ceramics has been described to modify brushite cements and improve their biological behavior. However, few studies have analyzed the efficiency of this approach to induce magnesium substitution in brushite crystals. Mg-doped ceramics composed of Mg-substituted β-TCP, stanfieldite and/or farringtonite were reacted with primary monocalcium phosphate (MCP) in the presence of water. The cement setting reaction has resulted in the formation of brushite and newberyite within the cement matrix. Interestingly, the combination of SAED and EDX analyses of single crystal has indicated the occurrence of magnesium substitution within brushite crystals. Moreover, the effect of magnesium ions on the structure, and mechanical and setting properties of the new cements was characterized as well as the release of Ca(2+) and Mg(2+) ions. Further research would enhance the efficiency of the system to incorporate larger amounts of magnesium ions within brushite crystals. PMID:25428098

  15. Bone grafts and their substitutes.

    PubMed

    Fillingham, Y; Jacobs, J

    2016-01-01

    The continual cycle of bone formation and resorption is carried out by osteoblasts, osteocytes, and osteoclasts under the direction of the bone-signaling pathway. In certain situations the host cycle of bone repair is insufficient and requires the assistance of bone grafts and their substitutes. The fundamental properties of a bone graft are osteoconduction, osteoinduction, osteogenesis, and structural support. Options for bone grafting include autogenous and allograft bone and the various isolated or combined substitutes of calcium sulphate, calcium phosphate, tricalcium phosphate, and coralline hydroxyapatite. Not all bone grafts will have the same properties. As a result, understanding the requirements of the clinical situation and specific properties of the various types of bone grafts is necessary to identify the ideal graft. We present a review of the bone repair process and properties of bone grafts and their substitutes to help guide the clinician in the decision making process. PMID:26733632

  16. Substitution systems and nonextensive statistics

    NASA Astrophysics Data System (ADS)

    García-Morales, V.

    2015-12-01

    Substitution systems evolve in time by generating sequences of symbols from a finite alphabet: At a certain iteration step, the existing symbols are systematically replaced by blocks of Nk symbols also within the alphabet (with Nk, a natural number, being the length of the kth block of the substitution). The dynamics of these systems leads naturally to fractals and self-similarity. By using B-calculus (García-Morales, 2012) universal maps for deterministic substitution systems both of constant and non-constant length, are formulated in 1D. It is then shown how these systems can be put in direct correspondence with Tsallis entropy. A 'Second Law of Thermodynamics' is also proved for these systems in the asymptotic limit of large words.

  17. Unified optical symbolic substitution processor

    NASA Astrophysics Data System (ADS)

    Casasent, David P.

    1990-07-01

    Symbolic substitution operations can be realized optically on a correlator. This is a very attractive and efficient architecture for symbolic substitution. It allows parallel multichannel realization with a fixed set of filters (on film or easily realized on low space bandwidth product spatial light modulators) using space and frequency-multiplexing or sequential filters. All basic logic, numeric and morphological image processing functions can be achieved by symbolic substitution. Moreover, all operations are possible on one multifunctional optical processor. Morphological operations are felt to be essential for ATR and pattern recognition preprocessing in clutter. They greatly improve the role for optics by allowing the same optical architecture to be used for low, medium and high level vision.

  18. Resistance-induced antibiotic substitution.

    PubMed

    Howard, David H

    2004-06-01

    In many cases, physicians prescribe antibiotics without knowing whether an individual patient is infected with a susceptible or resistant pathogen. As the proportion of resistant organisms in a community increases, physicians substitute away from older-inexpensive drugs to newer, more expensive agents as first line therapy. This paper explores the implications of resistance-induced antibiotic substitution for epidemiological models to predict future resistance levels, efforts to measure the health care costs associated with resistance, and policies to improve physicians' antibiotic prescribing decisions. The extent of resistance-induced substitution in outpatient settings is documented using a data set consisting of observations on initial physician office visits for otitis media in the US controlling for new product introductions and price increases, per prescription antibiotic spending increased by 22% between 1980 and 1996, corresponding to a steep increase in resistance levels over the same period. PMID:15185388

  19. 40 CFR 721.10214 - Poly(oxyalkylenediyl),.alpha.-substituted carbomonocycle-.omega.-substituted carbomonocycle...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Poly(oxyalkylenediyl),.alpha... Poly(oxyalkylenediyl),.alpha.-substituted carbomonocycle-.omega.-substituted carbomonocycle (generic... identified generically as poly(oxyalkylenediyl),.alpha.-substituted...

  20. 40 CFR 721.10214 - Poly(oxyalkylenediyl),.alpha.-substituted carbomonocycle-.omega.-substituted carbomonocycle...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Poly(oxyalkylenediyl),.alpha... Poly(oxyalkylenediyl),.alpha.-substituted carbomonocycle-.omega.-substituted carbomonocycle (generic... identified generically as poly(oxyalkylenediyl),.alpha.-substituted...

  1. 40 CFR 721.10214 - Poly(oxyalkylenediyl),.alpha.-substituted carbomonocycle-.omega.-substituted carbomonocycle...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Poly(oxyalkylenediyl),.alpha... Poly(oxyalkylenediyl),.alpha.-substituted carbomonocycle-.omega.-substituted carbomonocycle (generic... identified generically as poly(oxyalkylenediyl),.alpha.-substituted...

  2. 40 CFR 721.10214 - Poly(oxyalkylenediyl),.alpha.-substituted carbomonocycle-.omega.-substituted carbomonocycle...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Poly(oxyalkylenediyl),.alpha... Poly(oxyalkylenediyl),.alpha.-substituted carbomonocycle-.omega.-substituted carbomonocycle (generic... identified generically as poly(oxyalkylenediyl),.alpha.-substituted...

  3. 'Vegetable' substitutes for diesel fuel

    SciTech Connect

    Not Available

    1981-07-22

    Research programs in the US, Brazil, South Africa and the Philippines on efforts to find a vegetable oil substitute for diesel fuel are reported. A narrowing price gap with diesel fuel and a favourable energy balance improve the prospects for such fuels. Much of the current work is centered on blends, rather than the use of the pure oil.

  4. 40 CFR 721.9100 - Substituted quinoline.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Substituted quinoline. 721.9100... Substances § 721.9100 Substituted quinoline. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as substituted quinoline (PMN P-93-1183)...

  5. 40 CFR 721.9100 - Substituted quinoline.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Substituted quinoline. 721.9100... Substances § 721.9100 Substituted quinoline. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as substituted quinoline (PMN P-93-1183)...

  6. 40 CFR 721.3360 - Substituted ethanolamine.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Substituted ethanolamine. 721.3360... Substances § 721.3360 Substituted ethanolamine. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as substituted ethanolamine (PMN P-91-490)...

  7. Ethynyl and substituted ethynyl-terminated polysulfones

    NASA Technical Reports Server (NTRS)

    Hergenrother, P. M. (Inventor)

    1984-01-01

    Ethynyl and substituted ethynyl-terminated polysulfones and a process for preparing the same are disclosed. These polysulfones are thermally cured to induce cross-linking and chain extension, producing a polymer system with improved solvent resistance and use temperature. Also disclosed are substituted 4-ethynylbenzoyl chlorides as precursors to the substituted ethynyl-terminated polysulfones and a process for preparing the same.

  8. Ethynyl and substituted ethynyl-terminated polysulfones

    NASA Technical Reports Server (NTRS)

    Hergenrother, P. M. (Inventor)

    1986-01-01

    Ethynyl and substituted ethynyl-terminated polysulfones and their synthesis are disclosed. These polysulfones are thermally cured to induce cross-linking and chain extension, producing a polymer system with improved solvent resistance and use temperatures. Also disclosed are substituted 4-ethynylbenzoyl chlorides as precursors to the substituted ethynyl-terminated polysulfones and a process for preparing the same.

  9. Permanent Teacher Preparation for Substitute Teachers.

    ERIC Educational Resources Information Center

    Hardman, Steve; Tippetts, Zachary

    2001-01-01

    Presents information about what should be communicated to substitute teachers and why it is important, focusing on the substitute teacher's role, classroom management tools, curriculum management, and preparing students for the substitute teacher by creating bridges that will help minimize the sense of separation students feel when they have a…

  10. 40 CFR 721.4280 - Substituted hydrazine.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Substituted hydrazine. 721.4280... Substances § 721.4280 Substituted hydrazine. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as substituted hydrazine (PMN P-90-594)...

  11. 40 CFR 721.4280 - Substituted hydrazine.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Substituted hydrazine. 721.4280... Substances § 721.4280 Substituted hydrazine. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as substituted hydrazine (PMN P-90-594)...

  12. 40 CFR 721.4280 - Substituted hydrazine.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Substituted hydrazine. 721.4280... Substances § 721.4280 Substituted hydrazine. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as substituted hydrazine (PMN P-90-594)...

  13. 40 CFR 721.4280 - Substituted hydrazine.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Substituted hydrazine. 721.4280... Substances § 721.4280 Substituted hydrazine. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as substituted hydrazine (PMN P-90-594)...

  14. 40 CFR 721.4280 - Substituted hydrazine.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Substituted hydrazine. 721.4280... Substances § 721.4280 Substituted hydrazine. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as substituted hydrazine (PMN P-90-594)...

  15. 40 CFR 721.5867 - Substituted phenol.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Substituted phenol. 721.5867 Section... Substances § 721.5867 Substituted phenol. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance generically identified as substituted phenol (PMNs P-89-1125,...

  16. 40 CFR 721.5867 - Substituted phenol.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Substituted phenol. 721.5867 Section... Substances § 721.5867 Substituted phenol. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance generically identified as substituted phenol (PMNs P-89-1125,...

  17. 40 CFR 721.5867 - Substituted phenol.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Substituted phenol. 721.5867 Section... Substances § 721.5867 Substituted phenol. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance generically identified as substituted phenol (PMNs P-89-1125,...

  18. 40 CFR 721.5867 - Substituted phenol.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Substituted phenol. 721.5867 Section... Substances § 721.5867 Substituted phenol. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance generically identified as substituted phenol (PMNs P-89-1125,...

  19. 40 CFR 721.5867 - Substituted phenol.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Substituted phenol. 721.5867 Section... Substances § 721.5867 Substituted phenol. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance generically identified as substituted phenol (PMNs P-89-1125,...

  20. 40 CFR 721.9820 - Substituted triazole.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Substituted triazole. 721.9820 Section... Substances § 721.9820 Substituted triazole. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance generically identified as a substituted triazole (PMN P-90-1731)...

  1. 40 CFR 721.9820 - Substituted triazole.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Substituted triazole. 721.9820 Section... Substances § 721.9820 Substituted triazole. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance generically identified as a substituted triazole (PMN P-90-1731)...

  2. 40 CFR 721.9820 - Substituted triazole.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Substituted triazole. 721.9820 Section... Substances § 721.9820 Substituted triazole. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance generically identified as a substituted triazole (PMN P-90-1731)...

  3. 40 CFR 721.9820 - Substituted triazole.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Substituted triazole. 721.9820 Section... Substances § 721.9820 Substituted triazole. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance generically identified as a substituted triazole (PMN P-90-1731)...

  4. 40 CFR 721.9820 - Substituted triazole.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Substituted triazole. 721.9820 Section... Substances § 721.9820 Substituted triazole. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance generically identified as a substituted triazole (PMN P-90-1731)...

  5. 24 CFR 221.252 - Substitute mortgagors.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 24 Housing and Urban Development 2 2010-04-01 2010-04-01 false Substitute mortgagors. 221.252... Cost Homes § 221.252 Substitute mortgagors. (a) Selling mortgagor. The mortgagee may effect the release... approval of a substitute mortgagor, as provided by this section. (b) Purchasing mortgagor. The...

  6. Substitutes for School Nurses in Illinois

    ERIC Educational Resources Information Center

    Vollinger, Linda Jeno; Bergren, Martha Dewey; Belmonte-Mann, Frances

    2011-01-01

    The purpose of this descriptive study was to explore utilization of nurse substitutes in the school setting in Illinois. The literature described personnel who staff the school health office in the absence of the school nurse and the barriers to obtaining nurse substitutes. There were no empirical studies conducted on school nurse substitutes in…

  7. Iridium-Catalyzed Allylic Substitution

    NASA Astrophysics Data System (ADS)

    Hartwig, John F.; Pouy, Mark J.

    Iridium-catalyzed asymmetric allylic substitution has become a valuable method to prepare products from the addition of nucleophiles at the more substituted carbon of an allyl unit. The most active and selective catalysts contain a phosphoramidite ligand possessing at least one arylethyl substituent on the nitrogen atom of the ligand. In these systems, the active catalyst is generated by a base-induced cyclometalation at the methyl group of this substituent to generate an iridium metalacycle bound by the COD ligand of the [Ir(COD)Cl]2 precursor and one additional labile dative ligand. Such complexes catalyze the reactions of linear allylic esters with alkylamines, arylamines, phenols, alcohols, imides, carbamates, ammonia, enolates and enolate equivalents, as well as typical stabilized carbon nucleophiles generated from malonates and cyanoesters. Iridium catalysts for enantioselective allylic substitution have also been generated from phosphorus ligands with substituents bound by heteroatoms, and an account of the studies of such systems, along with a description of the development of iridium catalysts is included.

  8. Resonant photodissociation in substituted benzenes

    NASA Astrophysics Data System (ADS)

    Scarborough, Tim; McAcy, Collin; Foote, David; Uiterwaal, Cornelis

    2011-05-01

    Cyclic aromatic molecules are abundant in organic chemistry, with a wide variety of applications, including pharmacology, pollution studies and genetic research. Among the simplest of these molecules is benzene (C6H6) , with many relevant molecules being benzene-like with a single atomic substitution. In such a substitution, the substituent determines a characteristic perturbation of the electronic structure of the molecule. We discuss the substitution of halogens into the ring (C6H5X), and its effects on the dynamics of ionization and dissociation of the molecule without the focal volume effect. In particular, using 800-nm, 50-fs laser pulses, we present results in the dissociation of fluorobenzene, chlorobenzene, bromobenzene and iodobenzene into the phenyl ring (C6H5) and the atomic halogen, and the subsequent ionization of these fragments. The impact of the ``heavy atom effect'' on a 1 (π , π*) -->3 (n , σ*) singlet-triplet intersystem crossing will be emphasized. Currently under investigation is whether such a dissociation can be treated as an effective source of the neutral substituent. This material is based upon work supported by the National Science Foundation under Grant No. PHY-0355235.

  9. 40 CFR 721.1555 - Substituted phenyl azo substituted benzenediazonium salt.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... benzenediazonium salt. 721.1555 Section 721.1555 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.1555 Substituted phenyl azo substituted benzenediazonium salt. (a... generically as a substituted phenyl azo substituted benzenediazonium salt (PMN P-92-652) is subject...

  10. 40 CFR 721.1555 - Substituted phenyl azo substituted benzenediazonium salt.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... benzenediazonium salt. 721.1555 Section 721.1555 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.1555 Substituted phenyl azo substituted benzenediazonium salt. (a... generically as a substituted phenyl azo substituted benzenediazonium salt (PMN P-92-652) is subject...

  11. 40 CFR 721.6920 - Butyl acrylate, polymer with substituted methyl styrene, methyl methacrylate, and substituted...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Butyl acrylate, polymer with... acrylate, polymer with substituted methyl styrene, methyl methacrylate, and substituted silane. (a... butyl acrylate, polymer with substituted methyl styrene, methyl methacrylate, and substituted...

  12. 40 CFR 721.1555 - Substituted phenyl azo substituted benzenediazonium salt.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... benzenediazonium salt. 721.1555 Section 721.1555 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.1555 Substituted phenyl azo substituted benzenediazonium salt. (a... generically as a substituted phenyl azo substituted benzenediazonium salt (PMN P-92-652) is subject...

  13. 40 CFR 721.9545 - Substituted phenyl azo substituted sulfocarbopolycle, sodium salt.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... sulfocarbopolycle, sodium salt. 721.9545 Section 721.9545 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.9545 Substituted phenyl azo substituted sulfocarbopolycle, sodium salt... identified generically as a substituted phenyl azo substituted sulfocarbopolycle, sodium salt (PMN...

  14. 40 CFR 721.9545 - Substituted phenyl azo substituted sulfocarbopolycle, sodium salt.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... sulfocarbopolycle, sodium salt. 721.9545 Section 721.9545 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.9545 Substituted phenyl azo substituted sulfocarbopolycle, sodium salt... identified generically as a substituted phenyl azo substituted sulfocarbopolycle, sodium salt (PMN...

  15. 40 CFR 721.9545 - Substituted phenyl azo substituted sulfocarbopolycle, sodium salt.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... sulfocarbopolycle, sodium salt. 721.9545 Section 721.9545 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.9545 Substituted phenyl azo substituted sulfocarbopolycle, sodium salt... identified generically as a substituted phenyl azo substituted sulfocarbopolycle, sodium salt (PMN...

  16. 40 CFR 721.9545 - Substituted phenyl azo substituted sulfocarbopolycle, sodium salt.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... sulfocarbopolycle, sodium salt. 721.9545 Section 721.9545 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.9545 Substituted phenyl azo substituted sulfocarbopolycle, sodium salt... identified generically as a substituted phenyl azo substituted sulfocarbopolycle, sodium salt (PMN...

  17. 40 CFR 721.9545 - Substituted phenyl azo substituted sulfocarbopolycle, sodium salt.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... sulfocarbopolycle, sodium salt. 721.9545 Section 721.9545 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.9545 Substituted phenyl azo substituted sulfocarbopolycle, sodium salt... identified generically as a substituted phenyl azo substituted sulfocarbopolycle, sodium salt (PMN...

  18. 40 CFR 721.1555 - Substituted phenyl azo substituted benzenediazonium salt.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... benzenediazonium salt. 721.1555 Section 721.1555 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.1555 Substituted phenyl azo substituted benzenediazonium salt. (a... generically as a substituted phenyl azo substituted benzenediazonium salt (PMN P-92-652) is subject...

  19. 40 CFR 721.1555 - Substituted phenyl azo substituted benzenediazonium salt.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... benzenediazonium salt. 721.1555 Section 721.1555 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.1555 Substituted phenyl azo substituted benzenediazonium salt. (a... generically as a substituted phenyl azo substituted benzenediazonium salt (PMN P-92-652) is subject...

  20. 40 CFR 721.6920 - Butyl acrylate, polymer with substituted methyl styrene, methyl methacrylate, and substituted...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Butyl acrylate, polymer with... acrylate, polymer with substituted methyl styrene, methyl methacrylate, and substituted silane. (a... butyl acrylate, polymer with substituted methyl styrene, methyl methacrylate, and substituted...

  1. The 213-amino-acid leucine-rich repeat region of the listeria monocytogenes InlB protein is sufficient for entry into mammalian cells, stimulation of PI 3-kinase and membrane ruffling.

    PubMed

    Braun, L; Nato, F; Payrastre, B; Mazié, J C; Cossart, P

    1999-10-01

    The Listeria monocytogenes InlB protein is a 630-amino-acid surface protein that mediates entry of the bacterium into a wide variety of cell types, including hepatocytes, fibroblasts and epithelial cells such as Vero, HEp-2 and HeLa cells. Invasion stimulates host proteins tyrosine phosphorylation, PI 3-kinase activity and rearrangements in the actin cytoskeleton. We previously showed that InlB is sufficient for entry of InlB-coated latex beads into cells and recent results indicate that purified InlB can stimulate PI 3-kinase activity and is thus the first bacterial agonist of this lipid kinase. In this study, we identified the region of InlB responsible for entry and stimulation of signal transduction events. Eight monoclonal antibodies directed against InlB were raised and, of those, five inhibited bacterial entry. These five antibodies recognized epitopes within the leucine-rich repeat (LRR) region and/or the inter-repeat (IR) region. InlB-staphylococcal protein A (SPA) fusion proteins and recombinant InlB derivatives were generated and tested for their capacity to mediate entry into cultured mammalian cells. All the InlB derivatives that carried the amino-terminal 213-amino-acid LRR region conferred invasiveness to the normally non-invasive bacterium L. innocua or to inert latex beads and the corresponding purified polypeptides inhibited bacterial entry. In addition, the 213-amino-acid LRR region was able to stimulate PI 3-kinase activity and changes in the actin cytoskeleton (membrane ruffling). These properties were not detected with purified internalin, another invasion protein of L. monocytogenes that displays LRRs similar to those of InlB. Taken together, these results show that the first 213 amino acids of InlB are critical for its specific properties. PMID:10540282

  2. Use This Test to Spruce Up Your Substitute Teacher Program.

    ERIC Educational Resources Information Center

    Sendor, Elizabeth

    1982-01-01

    Presents and interprets an 18-question test to determine how well a school's substitute teacher program functions. Topics covered include substitute teacher screening and preparation, lists of substitutes, lesson plans, staff and student evaluation of substitutes, substitutes' salaries, legal considerations, and making substitutes feel needed.…

  3. Sensory substitution as an artificially acquired synaesthesia.

    PubMed

    Ward, Jamie; Wright, Thomas

    2014-04-01

    In this review we explore the relationship between synaesthesia and sensory substitution and argue that sensory substitution does indeed show properties of synaesthesia. Both are associated with atypical perceptual experiences elicited by the processing of a qualitatively different stimulus to that which normally gives rise to that experience. In the most common forms of sensory substitution, perceptual processing of an auditory or tactile signal (which has been converted from a visual signal) is experienced as visual-like in addition to retaining auditory/tactile characteristics. We consider different lines of evidence that support, to varying degrees, the assumption that sensory substitution is associated with visual-like experiences. We then go on to analyse the key similarities and differences between sensory substitution and synaesthesia. Lastly, we propose two testable predictions: firstly that, in an expert user of a sensory substitution device, the substituting modality should not be lost. Secondly that stimulation within the substituting modality, but by means other than a sensory substitution device, should still produce sensation in the normally substituted modality. PMID:22885223

  4. Biologic and synthetic skin substitutes: An overview

    PubMed Central

    Halim, Ahmad Sukari; Khoo, Teng Lye; Mohd. Yussof, Shah Jumaat

    2010-01-01

    The current trend of burn wound care has shifted to more holistic approach of improvement in the long-term form and function of the healed burn wounds and quality of life. This has demanded the emergence of various skin substitutes in the management of acute burn injury as well as post burn reconstructions. Skin substitutes have important roles in the treatment of deep dermal and full thickness wounds of various aetiologies. At present, there is no ideal substitute in the market. Skin substitutes can be divided into two main classes, namely, biological and synthetic substitutes. The biological skin substitutes have a more intact extracellular matrix structure, while the synthetic skin substitutes can be synthesised on demand and can be modulated for specific purposes. Each class has its advantages and disadvantages. The biological skin substitutes may allow the construction of a more natural new dermis and allow excellent re-epithelialisation characteristics due to the presence of a basement membrane. Synthetic skin substitutes demonstrate the advantages of increase control over scaffold composition. The ultimate goal is to achieve an ideal skin substitute that provides an effective and scar-free wound healing. PMID:21321652

  5. Substituted Pyrrolo[2,3-d]pyrimidines as Cryptosporidium hominis Thymidylate Synthase Inhibitors

    PubMed Central

    Kumar, Vidya P.; Frey, Kathleen M.; Wang, Yiqiang; Jain, Hitesh K.; Gangjee, Aleem; Anderson, Karen S.

    2013-01-01

    Cryptosporidiosis, a gastrointestinal disease caused by a protozoan Cryptosporidium hominis is often fatal in immunocompromised individuals. There is little clinical data to show that the existing treatment by nitazoxanide and paromomycin is effective in immunocompromised individuals1, 2. Thymidylate synthase (TS) and dihydrofolate reductase (DHFR) are essential enzymes in the folate biosynthesis pathway and are well established as drug targets in cancer and malaria. A novel series of classical antifolates, 2-amino-4-oxo-5-substituted pyrrolo[2,3-d]pyrimidines have been evaluated as Cryptosporidium hominis thymidylate synthase (ChTS) inhibitors. Crystal structure in complex with the most potent compound, a 2’-chlorophenyl with a sulfur bridge with a Ki of 8.83 ± 0.67 nM is discussed in terms of several Van de Waals, hydrophobic and hydrogen bond interactions with the protein residues and the substrate analog 5-fluorodeoxyuridine monophosphate. Of these interactions, two interactions with the non-conserved residues (A287 and S290) offer an opportunity to develop ChTS specific inhibitors. Compound 6 serves as a lead compound for analog design and its crystal structure provides clues for the design of ChTS specific inhibitors. PMID:23927969

  6. Trends in substitution models of molecular evolution.

    PubMed

    Arenas, Miguel

    2015-01-01

    Substitution models of evolution describe the process of genetic variation through fixed mutations and constitute the basis of the evolutionary analysis at the molecular level. Almost 40 years after the development of first substitution models, highly sophisticated, and data-specific substitution models continue emerging with the aim of better mimicking real evolutionary processes. Here I describe current trends in substitution models of DNA, codon and amino acid sequence evolution, including advantages and pitfalls of the most popular models. The perspective concludes that despite the large number of currently available substitution models, further research is required for more realistic modeling, especially for DNA coding and amino acid data. Additionally, the development of more accurate complex models should be coupled with new implementations and improvements of methods and frameworks for substitution model selection and downstream evolutionary analysis. PMID:26579193

  7. Trends in substitution models of molecular evolution

    PubMed Central

    Arenas, Miguel

    2015-01-01

    Substitution models of evolution describe the process of genetic variation through fixed mutations and constitute the basis of the evolutionary analysis at the molecular level. Almost 40 years after the development of first substitution models, highly sophisticated, and data-specific substitution models continue emerging with the aim of better mimicking real evolutionary processes. Here I describe current trends in substitution models of DNA, codon and amino acid sequence evolution, including advantages and pitfalls of the most popular models. The perspective concludes that despite the large number of currently available substitution models, further research is required for more realistic modeling, especially for DNA coding and amino acid data. Additionally, the development of more accurate complex models should be coupled with new implementations and improvements of methods and frameworks for substitution model selection and downstream evolutionary analysis. PMID:26579193

  8. Formation of substituted oxa- and azarhodacyclobutanes.

    PubMed

    Dauth, Alexander; Rigling, Carla; Tsoung, Jennifer; Love, Jennifer A

    2013-12-01

    The preparation of substituted oxa- and azarhodacyclobutanes is reported. After exchange of ethylene with a variety of unsymmetrically and symmetrically substituted alkenes, the corresponding rhodium-olefin complexes were oxidized with H2O2 and PhINTs (Ts=p-toluenesulfonyl) to yield the substituted oxa- and azarhodacyclobutanes, respectively. Oxarhodacyclobutanes could be prepared with excellent selectivity for incorporation of the oxygen atom on the more substituted carbon atom of the alkene. At the same time, azarhodacyclobutanes showed good-to-excellent selectivity for heteroatom incorporation on the less substituted carbon. Furthermore, it was shown that steric modifications of the ancillary ligand have a significant influence on the selectivity of Rh-olefin complex formation as well as formation of the substituted azametallacycles. PMID:24307371

  9. Oncogenicity of L-type amino-acid transporter 1 (LAT1) revealed by targeted gene disruption in chicken DT40 cells: LAT1 is a promising molecular target for human cancer therapy

    SciTech Connect

    Ohkawa, Mayumi; Ohno, Yoshiya; Masuko, Kazue; Takeuchi, Akiko; Suda, Kentaro; Kubo, Akihiro; Kawahara, Rieko; Okazaki, Shogo; Tanaka, Toshiyuki; Saya, Hideyuki; Seki, Masayuki; Enomoto, Takemi; Yagi, Hideki; Hashimoto, Yoshiyuki; Masuko, Takashi

    2011-03-25

    Highlights: {yields} We established LAT1 amino-acid transporter-disrupted DT40 cells. {yields} LAT1-disrupted cells showed slow growth and lost the oncogenicity. {yields} siRNA and mAb inhibited human tumor growth in vitro and in vivo. {yields} LAT1 is a promising target molecule for cancer therapy. -- Abstract: L-type amino-acid transporter 1 (LAT1) is the first identified light chain of CD98 molecule, disulfide-linked to a heavy chain of CD98. Following cDNA cloning of chicken full-length LAT1, we have constructed targeting vectors for the disruption of chicken LAT1 gene from genomic DNA of chicken LAT1 consisting of 5.4 kb. We established five homozygous LAT1-disrupted (LAT1{sup -/-}) cell clones, derived from a heterozygous LAT1{sup +/-} clone of DT40 chicken B cell line. Reactivity of anti-chicken CD98hc monoclonal antibody (mAb) with LAT1{sup -/-} DT40 cells was markedly decreased compared with that of wild-type DT40 cells. All LAT1{sup -/-} cells were deficient in L-type amino-acid transporting activity, although alternative-splice variant but not full-length mRNA of LAT1 was detected in these cells. LAT1{sup -/-} DT40 clones showed outstandingly slow growth in liquid culture and decreased colony-formation capacity in soft agar compared with wild-type DT40 cells. Cell-cycle analyses indicated that LAT1{sup -/-} DT40 clones have prolonged cell-cycle phases compared with wild-type or LAT1{sup +/-} DT40 cells. Knockdown of human LAT1 by small interfering RNAs resulted in marked in vitro cell-growth inhibition of human cancer cells, and in vivo tumor growth of HeLa cells in athymic mice was significantly inhibited by anti-human LAT1 mAb. All these results indicate essential roles of LAT1 in the cell proliferation and occurrence of malignant phenotypes and that LAT1 is a promising candidate as a molecular target of human cancer therapy.

  10. 40 CFR 721.5340 - Substituted benzothiazole-azo-substituted benzoquinoline nickel complex (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...-substituted benzoquinoline nickel complex (generic). 721.5340 Section 721.5340 Protection of Environment...-substituted benzoquinoline nickel complex (generic). (a) Chemical substance and significant new uses subject...-substituted benzoquinoline nickel complex (PMN P-99-897) is subject to reporting under this section for...

  11. 40 CFR 721.5340 - Substituted benzothiazole-azo-substituted benzoquinoline nickel complex (generic).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...-substituted benzoquinoline nickel complex (generic). 721.5340 Section 721.5340 Protection of Environment...-substituted benzoquinoline nickel complex (generic). (a) Chemical substance and significant new uses subject...-substituted benzoquinoline nickel complex (PMN P-99-897) is subject to reporting under this section for...

  12. 40 CFR 721.5340 - Substituted benzothiazole-azo-substituted benzoquinoline nickel complex (generic).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...-substituted benzoquinoline nickel complex (generic). 721.5340 Section 721.5340 Protection of Environment...-substituted benzoquinoline nickel complex (generic). (a) Chemical substance and significant new uses subject...-substituted benzoquinoline nickel complex (PMN P-99-897) is subject to reporting under this section for...

  13. 40 CFR 721.5340 - Substituted benzothiazole-azo-substituted benzoquinoline nickel complex (generic).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...-substituted benzoquinoline nickel complex (generic). 721.5340 Section 721.5340 Protection of Environment...-substituted benzoquinoline nickel complex (generic). (a) Chemical substance and significant new uses subject...-substituted benzoquinoline nickel complex (PMN P-99-897) is subject to reporting under this section for...

  14. 40 CFR 721.5340 - Substituted benzothiazole-azo-substituted benzoquinoline nickel complex (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...-substituted benzoquinoline nickel complex (generic). 721.5340 Section 721.5340 Protection of Environment...-substituted benzoquinoline nickel complex (generic). (a) Chemical substance and significant new uses subject...-substituted benzoquinoline nickel complex (PMN P-99-897) is subject to reporting under this section for...

  15. 40 CFR 721.2577 - Copper complex of (substituted sulfonaphthyl azo substituted phenyl) disulfonaphthyl azo, amine...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Copper complex of (substituted... Copper complex of (substituted sulfonaphthyl azo substituted phenyl) disulfonaphthyl azo, amine salt... significant new uses subject to reporting. (1) The chemical substances identified generically as...

  16. 40 CFR 721.10497 - Substituted alkyl ester, hydrolysis products with silica and substituted silane (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... products with silica and substituted silane (generic). 721.10497 Section 721.10497 Protection of... ester, hydrolysis products with silica and substituted silane (generic). (a) Chemical substance and... alkyl ester, hydrolysis products with silica and substituted silane (PMNs P-06-276 and P-06-279)...

  17. 40 CFR 721.10497 - Substituted alkyl ester, hydrolysis products with silica and substituted silane (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... products with silica and substituted silane (generic). 721.10497 Section 721.10497 Protection of... ester, hydrolysis products with silica and substituted silane (generic). (a) Chemical substance and... alkyl ester, hydrolysis products with silica and substituted silane (PMNs P-06-276 and P-06-279)...

  18. 40 CFR Appendix D to Subpart G of... - Substitutes Subject to Use Restrictions and Unacceptable Substitutes

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Comments Electronics Cleaning w/CFC-113 and MCF HFC-4310mee Acceptable Subject to a 200 ppm time-weighted... Electronics Cleaning w/CFC-113 and MCF Perfluoropolyethers Perfluoropolyethers are acceptable substitutes for... that for PFCs. Unacceptable Substitutes End-use Substitute Decision Comments Electronics Cleaning...

  19. 40 CFR 721.323 - Substituted acrylamide.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... CONTROL ACT SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.323 Substituted acrylamide. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance generically identified as substituted acrylamide (PMN P-90-1687)...

  20. 40 CFR 721.323 - Substituted acrylamide.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... CONTROL ACT SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.323 Substituted acrylamide. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance generically identified as substituted acrylamide (PMN P-90-1687)...

  1. Substitute Teachers: Making Lost Days Count

    ERIC Educational Resources Information Center

    True, Charlene; Butler, Kyle; Sefton, Rachel

    2011-01-01

    As K-12 teachers and administrators grow increasingly concerned with issues of accountability, research-based methods, and intervention strategies, little discussion exists on the impact of substitute teachers in the classroom. In the rush to analyze test scores, are the days covered by substitute teachers even considered? Though districts are…

  2. Substitutes for Leadership: An Empirical Study.

    ERIC Educational Resources Information Center

    Howell, Jon P.; Dorfman, Peter W.

    The leadership substitutes hypothesis has been used to explain the occasional successes and frequent failures of leadership predictions. Three hypotheses were formulated to test the viability of the leadership substitutes concepts. Questionnaires were administered to hospital managers (N=63) and engineers (N=71). Instrumental and supportive leader…

  3. Carboranylmethylene-substituted phosphazenes and polymers thereof

    NASA Technical Reports Server (NTRS)

    Allcock, H. R.; Scopelianos, A. G. (Inventor)

    1984-01-01

    Carboranylmethylene-substituted cyclophosphazenes are described which can be thermally polymerized into carboranylmethylene-substituted phosphazene polymers. The polymers are useful as thermally stable coatings. Also, due to the characteristics of these polymers in acting as a ligand for transition metals, metalocarboranylmethylene phosphazene polymers are described which can act as immobilized catalyst systems, and are electrically conductive and superconductive.

  4. 40 CFR 721.323 - Substituted acrylamide.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Substituted acrylamide. 721.323 Section 721.323 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.323 Substituted acrylamide....

  5. Educators Take Another Look at Substitutes

    ERIC Educational Resources Information Center

    Zubrzycki, Jaclyn

    2012-01-01

    The mythology surrounding the substitute teacher is not a pretty one: Paper airplanes, lost learning, bullying. But as schools collect more information about teacher absenteeism and its consequences, districts and schools are exploring ways to professionalize substitute teaching--or experiment with alternative ways of coping with teacher absences.…

  6. Dimensions of Needs in Secondary Substitute Teaching.

    ERIC Educational Resources Information Center

    Dilanian, Seta Margo

    Following a brief review of research and literature regarding the needs of secondary school substitute teachers, suggestions for helping these teachers do an effective, professional job are offered. Research indicates that understanding of the subject matter along with understanding of various learning approaches enhances the substitute teacher's…

  7. Savvy Substitutions. Tricks of the Trade.

    ERIC Educational Resources Information Center

    Guhin, Paula

    2000-01-01

    Provides ideas for using throwaways and substitutions, such as homemade objects and everyday items, as art supplies and other resources in the art classroom. Throwaways and substitutions are a way to be environmentally caring, to extend meager supplies, and to supplement art budgets. (CMK)

  8. 24 CFR 235.206 - Substitute mortgagors.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 24 Housing and Urban Development 2 2010-04-01 2010-04-01 false Substitute mortgagors. 235.206... MORTGAGE INSURANCE AND ASSISTANCE PAYMENTS FOR HOME OWNERSHIP AND PROJECT REHABILITATION Contract Rights and Obligations-Homes for Lower Income Families § 235.206 Substitute mortgagors. (a) Selling...

  9. Substitute Your Way to a Real Job

    ERIC Educational Resources Information Center

    Stephens, Cathy

    2013-01-01

    For some, substitute teaching is a career choice. However, for the majority of new teachers, it is often a necessary gateway to landing a first job. Either way, it is a great way to sharpen one's skills. This article presents tips from principals, teachers, and human resource directors to make the most of the substitute teaching experience…

  10. 25 CFR 522.9 - Substitute approval.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 2 2010-04-01 2010-04-01 false Substitute approval. 522.9 Section 522.9 Indians NATIONAL INDIAN GAMING COMMISSION, DEPARTMENT OF THE INTERIOR APPROVAL OF CLASS II AND CLASS III ORDINANCES AND RESOLUTIONS SUBMISSION OF GAMING ORDINANCE OR RESOLUTION § 522.9 Substitute approval. If the Chairman fails...